Avian thermoregulation in the heat: phylogenetic variation among avian orders in evaporative cooling capacity and heat tolerance
- Smit, Ben, Whitfield, Maxine C, Talbot, William A, Gerson, Alexander R, McKechnie, Andrew E, Wolf, Blair O
- Authors: Smit, Ben , Whitfield, Maxine C , Talbot, William A , Gerson, Alexander R , McKechnie, Andrew E , Wolf, Blair O
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/440517 , vital:73789 , https://doi.org/10.1242/jeb.174870
- Description: Little is known about the phylogenetic variation of avian evaporative cooling efficiency and heat tolerance in hot environments. We quantified thermoregulatory responses to high air temperature (Ta) in ∼100-g representatives of three orders, namely, the African cuckoo (Cuculus gularis, Cuculiformes), lilac-breasted roller (Coracias caudatus, Coraciiformes) and Burchell's starling (Lamprotornis australis, Passeriformes). All three species initiated respiratory mechanisms to increase evaporative heat dissipation when body temperature (Tb) approached 41.5°C in response to increasing Ta, with gular flutter observed in cuckoos and panting in rollers and starlings. Resting metabolic rate and evaporative water loss increased by quantitatively similar magnitudes in all three species, although maximum rates of evaporative water loss were proportionately lower in starlings. Evaporative cooling efficiency [defined as the ratio of evaporative heat loss (EHL) to metabolic heat production (MHP)] generally remained below 2.0 in cuckoos and starlings, but reached a maximum of ∼3.5 in rollers. The high value for rollers reveals a very efficient evaporative cooling mechanism, and is similar to EHL/MHP maxima for similarly sized columbids which very effectively dissipate heat via cutaneous evaporation. This unexpected phylogenetic variation among the orders tested in the physiological mechanisms of heat dissipation is an important step toward determining the evolution of heat tolerance traits in desert birds.
- Full Text:
- Date Issued: 2018
- Authors: Smit, Ben , Whitfield, Maxine C , Talbot, William A , Gerson, Alexander R , McKechnie, Andrew E , Wolf, Blair O
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/440517 , vital:73789 , https://doi.org/10.1242/jeb.174870
- Description: Little is known about the phylogenetic variation of avian evaporative cooling efficiency and heat tolerance in hot environments. We quantified thermoregulatory responses to high air temperature (Ta) in ∼100-g representatives of three orders, namely, the African cuckoo (Cuculus gularis, Cuculiformes), lilac-breasted roller (Coracias caudatus, Coraciiformes) and Burchell's starling (Lamprotornis australis, Passeriformes). All three species initiated respiratory mechanisms to increase evaporative heat dissipation when body temperature (Tb) approached 41.5°C in response to increasing Ta, with gular flutter observed in cuckoos and panting in rollers and starlings. Resting metabolic rate and evaporative water loss increased by quantitatively similar magnitudes in all three species, although maximum rates of evaporative water loss were proportionately lower in starlings. Evaporative cooling efficiency [defined as the ratio of evaporative heat loss (EHL) to metabolic heat production (MHP)] generally remained below 2.0 in cuckoos and starlings, but reached a maximum of ∼3.5 in rollers. The high value for rollers reveals a very efficient evaporative cooling mechanism, and is similar to EHL/MHP maxima for similarly sized columbids which very effectively dissipate heat via cutaneous evaporation. This unexpected phylogenetic variation among the orders tested in the physiological mechanisms of heat dissipation is an important step toward determining the evolution of heat tolerance traits in desert birds.
- Full Text:
- Date Issued: 2018
Expanding the SAR of Nontoxic Antiplasmodial Indolyl-3-ethanone Ethers and Thioethers:
- Lunga, Mayibongwe J, Chisango, Ruramai L, Weyers, Carli, Isaacs, Michelle, Taylor, Dale, Edkins, Adrienne L, Khanye, Setshaba D, Hoppe, Heinrich C, Veale, Clinton G L
- Authors: Lunga, Mayibongwe J , Chisango, Ruramai L , Weyers, Carli , Isaacs, Michelle , Taylor, Dale , Edkins, Adrienne L , Khanye, Setshaba D , Hoppe, Heinrich C , Veale, Clinton G L
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/164389 , vital:41114 , DOI: 10.1002/cmdc.201800235
- Description: Despite major strides in reducing Plasmodium falciparum infections, this parasite still accounts for roughly half a million annual deaths. This problem is compounded by the decreased efficacy of artemisinin combination therapies. Therefore, the development and optimisation of novel antimalarial chemotypes is critical. In this study, we describe our strategic approach to optimise a class of previously reported antimalarials, resulting in the discovery of 1-(5-chloro-1H-indol-3-yl)-2-[(4-cyanophenyl)thio]ethanone (13) and 1-(5-chloro-1H-indol-3-yl)-2-[(4-nitrophenyl)thio]ethanone (14), whose activity was equipotent to that of chloroquine against the P. falciparum 3D7 strain.
- Full Text:
- Date Issued: 2018
- Authors: Lunga, Mayibongwe J , Chisango, Ruramai L , Weyers, Carli , Isaacs, Michelle , Taylor, Dale , Edkins, Adrienne L , Khanye, Setshaba D , Hoppe, Heinrich C , Veale, Clinton G L
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/164389 , vital:41114 , DOI: 10.1002/cmdc.201800235
- Description: Despite major strides in reducing Plasmodium falciparum infections, this parasite still accounts for roughly half a million annual deaths. This problem is compounded by the decreased efficacy of artemisinin combination therapies. Therefore, the development and optimisation of novel antimalarial chemotypes is critical. In this study, we describe our strategic approach to optimise a class of previously reported antimalarials, resulting in the discovery of 1-(5-chloro-1H-indol-3-yl)-2-[(4-cyanophenyl)thio]ethanone (13) and 1-(5-chloro-1H-indol-3-yl)-2-[(4-nitrophenyl)thio]ethanone (14), whose activity was equipotent to that of chloroquine against the P. falciparum 3D7 strain.
- Full Text:
- Date Issued: 2018
Exploration and design of a synchronous message passing framework for a CPU-NPU heterogeneous architecture
- Pennefather, Sean, Bradshaw, Karen L, Irwin, Barry V W
- Authors: Pennefather, Sean , Bradshaw, Karen L , Irwin, Barry V W
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429537 , vital:72620 , https://ieeexplore.ieee.org/abstract/document/8425384
- Description: In this paper we present the development of a framework for communication between an NPU (network processing unit) and CPU through synchronous message passing that is compliant with the synchronous communication events of the CSP formalisms. This framework is designed to be used for passing generic information between application components operating on both architectures and is intended to operate in conjunction with existing datapaths present on the NPU which in turn are responsible for network traffic transmission. An investigation of different message passing topologies is covered before the proposed message passing fabric is presented. As a proof of concept, an initial implementation of the fabric is developed and tested to determine its viability and correctness. Through testing it is shown that the implemented framework operates as intended. However, it is noted the throughput of the exploratory implementation is not considered suitable for high-performance applications and further evaluation is required.
- Full Text:
- Date Issued: 2018
- Authors: Pennefather, Sean , Bradshaw, Karen L , Irwin, Barry V W
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429537 , vital:72620 , https://ieeexplore.ieee.org/abstract/document/8425384
- Description: In this paper we present the development of a framework for communication between an NPU (network processing unit) and CPU through synchronous message passing that is compliant with the synchronous communication events of the CSP formalisms. This framework is designed to be used for passing generic information between application components operating on both architectures and is intended to operate in conjunction with existing datapaths present on the NPU which in turn are responsible for network traffic transmission. An investigation of different message passing topologies is covered before the proposed message passing fabric is presented. As a proof of concept, an initial implementation of the fabric is developed and tested to determine its viability and correctness. Through testing it is shown that the implemented framework operates as intended. However, it is noted the throughput of the exploratory implementation is not considered suitable for high-performance applications and further evaluation is required.
- Full Text:
- Date Issued: 2018
Introduction: Blurring Boundaries
- Mnyaka, Phindezwa, Macleod, Catriona I
- Authors: Mnyaka, Phindezwa , Macleod, Catriona I
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434252 , vital:73042 , ISBN 978-3-319-74720-0 , https://link.springer.com/chapter/10.1007/978-3-319-74721-7_9
- Description: This chapter introduces the section on blurring boundaries in research. The chapters within this section unpack the ethical dilemmas that researchers negotiate when they find themselves stepping outside their roles as researchers in the field. Research encounters presuppose particular boundaries, depending on the methodology employed and the research questions posed. However, participants may identify researchers differently, compelling them to respond in unanticipated ways as possibly therapists, clinicians, interlocutors, and activists. Collectively, the authors of the chapters in this section explore the ethical implications of blurring such boundaries. They unpack the significance of various forms of intimacies that may emerge while undertaking research, how researchers are positioned as agents of social change, and how researchers negotiate their statuses as insiders and outsiders in fieldwork.
- Full Text:
- Date Issued: 2018
- Authors: Mnyaka, Phindezwa , Macleod, Catriona I
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , book chapter
- Identifier: http://hdl.handle.net/10962/434252 , vital:73042 , ISBN 978-3-319-74720-0 , https://link.springer.com/chapter/10.1007/978-3-319-74721-7_9
- Description: This chapter introduces the section on blurring boundaries in research. The chapters within this section unpack the ethical dilemmas that researchers negotiate when they find themselves stepping outside their roles as researchers in the field. Research encounters presuppose particular boundaries, depending on the methodology employed and the research questions posed. However, participants may identify researchers differently, compelling them to respond in unanticipated ways as possibly therapists, clinicians, interlocutors, and activists. Collectively, the authors of the chapters in this section explore the ethical implications of blurring such boundaries. They unpack the significance of various forms of intimacies that may emerge while undertaking research, how researchers are positioned as agents of social change, and how researchers negotiate their statuses as insiders and outsiders in fieldwork.
- Full Text:
- Date Issued: 2018
Purification and characterization of an amyloglucosidase from an ericoid mycorrhizal fungus (Leohumicola incrustata)
- Adeoyo, Olusegun R, Pletschke, Brett I, Dames, Joanna F
- Authors: Adeoyo, Olusegun R , Pletschke, Brett I , Dames, Joanna F
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/440405 , vital:73780 , https://doi.org/10.1186/s13568-018-0685-1
- Description: This study aimed to purify and characterize amyloglucosidase (AMG) from Leohumicola incrustata. AMG was purified to homogeneity from cell-free culture filtrate of an ERM fungus grown in a modified Melin–Norkrans liquid medium. The molecular mass of the AMG was estimated to be 101 kDa by combining the results of Sephadex G-100 gel filtration, sodium dodecyl sulphate–polyacrylamide gel electrophoresis, and zymography. The Km and kcat values were 0.38 mg mL−1 and 70 s−1, respectively, using soluble starch as a substrate. The enzyme was stable at 45 °C (pH 5.0), retaining over 65% activity after a pre-incubation period of 24 h. The metal inhibition profile of the AMG showed that Mn2+ and Ca2+ enhanced activity, while it was stable to metals ions, except a few (Al3+, Co2+, Hg2+ and Cd2+) that were inhibitory at a concentration higher than 5 mM. Thin layer chromatography revealed that only glucose was produced as the product of starch hydrolysis. The amylase from L. incrustata is a glucoamylase with promising characteristics such as temperature stability over an extended period, high substrate affinity and stability to a range of chemicals. Also, this study reports for the first time the possibility of using some culturable ERM fungi to produce enzymes for the bio-economy.
- Full Text:
- Date Issued: 2018
- Authors: Adeoyo, Olusegun R , Pletschke, Brett I , Dames, Joanna F
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/440405 , vital:73780 , https://doi.org/10.1186/s13568-018-0685-1
- Description: This study aimed to purify and characterize amyloglucosidase (AMG) from Leohumicola incrustata. AMG was purified to homogeneity from cell-free culture filtrate of an ERM fungus grown in a modified Melin–Norkrans liquid medium. The molecular mass of the AMG was estimated to be 101 kDa by combining the results of Sephadex G-100 gel filtration, sodium dodecyl sulphate–polyacrylamide gel electrophoresis, and zymography. The Km and kcat values were 0.38 mg mL−1 and 70 s−1, respectively, using soluble starch as a substrate. The enzyme was stable at 45 °C (pH 5.0), retaining over 65% activity after a pre-incubation period of 24 h. The metal inhibition profile of the AMG showed that Mn2+ and Ca2+ enhanced activity, while it was stable to metals ions, except a few (Al3+, Co2+, Hg2+ and Cd2+) that were inhibitory at a concentration higher than 5 mM. Thin layer chromatography revealed that only glucose was produced as the product of starch hydrolysis. The amylase from L. incrustata is a glucoamylase with promising characteristics such as temperature stability over an extended period, high substrate affinity and stability to a range of chemicals. Also, this study reports for the first time the possibility of using some culturable ERM fungi to produce enzymes for the bio-economy.
- Full Text:
- Date Issued: 2018
Seasonal physiological responses to heat in an alpine range-restricted bird: the Cape Rockjumper (Chaetops frenatus)
- Oswald, Krista N, Lee, Alan T K, Smit, Ben
- Authors: Oswald, Krista N , Lee, Alan T K , Smit, Ben
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441655 , vital:73904 , https://doi.org/10.1007/s10336-018-1582-8
- Description: Hot, dry summer conditions impose physiological stress on endotherms, yet we have a poor understanding of how endotherms seasonally adjust their costs of thermoregulation under hot conditions. We determined whether seasonal phenotypic plasticity in evaporative cooling capacity at high temperatures explained how the range-restricted Cape Rockjumper (Chaetops frenatus; hereafter ‘Rockjumper’), copes with hot and dry summer temperatures of the temperate mountain peaks of southwest South Africa. We measured evaporative water loss (EWL), resting metabolic rate (RMR), and body temperature at high air temperatures (30–42 °C) of individuals from a wild population of Rockjumpers during winter and summer (n = 11 winter, 4 females, 7 males; n = 10 summer, 6 females, 4 males). We found Rockjumper evaporative cooling in summer imposes higher EWL (i.e. greater water costs) compared to winter, although an accompanying lack of change in RMR resulted in increased summer cooling efficiency. These patterns are similar to those observed in species that inhabit regions where summer temperatures are routinely high but the species are not water stressed. Our findings indicate that avian seasonal physiological adjustments to heat can be diverse. Further seasonal studies on thermoregulation in response to heat will greatly improve our knowledge of the functional value of traits such as evaporative cooling efficiency and heat tolerance and how they contribute to the physiological stress organisms experience in heterogenous environments.
- Full Text:
- Date Issued: 2018
- Authors: Oswald, Krista N , Lee, Alan T K , Smit, Ben
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/441655 , vital:73904 , https://doi.org/10.1007/s10336-018-1582-8
- Description: Hot, dry summer conditions impose physiological stress on endotherms, yet we have a poor understanding of how endotherms seasonally adjust their costs of thermoregulation under hot conditions. We determined whether seasonal phenotypic plasticity in evaporative cooling capacity at high temperatures explained how the range-restricted Cape Rockjumper (Chaetops frenatus; hereafter ‘Rockjumper’), copes with hot and dry summer temperatures of the temperate mountain peaks of southwest South Africa. We measured evaporative water loss (EWL), resting metabolic rate (RMR), and body temperature at high air temperatures (30–42 °C) of individuals from a wild population of Rockjumpers during winter and summer (n = 11 winter, 4 females, 7 males; n = 10 summer, 6 females, 4 males). We found Rockjumper evaporative cooling in summer imposes higher EWL (i.e. greater water costs) compared to winter, although an accompanying lack of change in RMR resulted in increased summer cooling efficiency. These patterns are similar to those observed in species that inhabit regions where summer temperatures are routinely high but the species are not water stressed. Our findings indicate that avian seasonal physiological adjustments to heat can be diverse. Further seasonal studies on thermoregulation in response to heat will greatly improve our knowledge of the functional value of traits such as evaporative cooling efficiency and heat tolerance and how they contribute to the physiological stress organisms experience in heterogenous environments.
- Full Text:
- Date Issued: 2018
When an Editor Decides to Listen to a City: Heather Robertson, The Herald, and Nelson Mandela Bay
- Garman, Anthea, Malila, Vanessa
- Authors: Garman, Anthea , Malila, Vanessa
- Date: 2018
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/158427 , vital:40185 , ISBN 9781351664363
- Description: This book provides case studies, many incorporating in-depth interviews and surveys of journalists. It examines issues such as journalists’ attitudes toward their contributions to society; the impact of industry and technological changes; culture and minority issues in the newsroom and profession; the impact of censorship and self-censorship; and coping with psychological pressures and physical safety dilemmas. Its chapters also highlight journalists’ challenges in national and multinational contexts. International scholars, conducting research within a wide range of authoritarian, semi-democratic, and democratic systems, contributed to this examination of journalistic practices in the Arab World, Australia, Bangladesh, Bulgaria, China, Denmark, India, Kenya, Kyrgyzstan, Malaysia, Mexico, Russia, Samoa, South Africa, Taiwan, Turkey, and the United States.
- Full Text:
- Date Issued: 2018
- Authors: Garman, Anthea , Malila, Vanessa
- Date: 2018
- Language: English
- Type: text , book
- Identifier: http://hdl.handle.net/10962/158427 , vital:40185 , ISBN 9781351664363
- Description: This book provides case studies, many incorporating in-depth interviews and surveys of journalists. It examines issues such as journalists’ attitudes toward their contributions to society; the impact of industry and technological changes; culture and minority issues in the newsroom and profession; the impact of censorship and self-censorship; and coping with psychological pressures and physical safety dilemmas. Its chapters also highlight journalists’ challenges in national and multinational contexts. International scholars, conducting research within a wide range of authoritarian, semi-democratic, and democratic systems, contributed to this examination of journalistic practices in the Arab World, Australia, Bangladesh, Bulgaria, China, Denmark, India, Kenya, Kyrgyzstan, Malaysia, Mexico, Russia, Samoa, South Africa, Taiwan, Turkey, and the United States.
- Full Text:
- Date Issued: 2018
“Two loves that I have, of comfort and despair”: the drama and architecture of Shakespeare’s sonnets
- Authors: van Wyk Smith, Malvern
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/453963 , vital:75301 , https://doi.org/10.1080/10130950.2007.9674885
- Description: This essay was delivered as the annual Shakespeare Birthday Lecture of the Shakespeare Society of Southern Africa in Grahamstown in 2017. It argues that Shakespeare’s predisposition to recognise and develop the dramatic moment turned his initial interest in the normally static and contemplative sonnet into the components of something more like an oratorio of dramatic variations in sonnet form. The author focuses on four sonnets (18, 30, 116, 129) that stake out the thematic and structural range of the whole sequence, and discusses how the poet explores the compositional and indeed architectonic possibilities inherent in the principles and procedures of pursuing ‘variations on a theme’. The sonnets can thus be understood as an ambitious proto-baroque diptych, the two halves of which were to present an elaborate allegory of love versus lust, trust versus deceit, and innocence versus experience.
- Full Text:
- Date Issued: 2018
“Two loves that I have, of comfort and despair”: the drama and architecture of Shakespeare’s sonnets
- Authors: van Wyk Smith, Malvern
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/453963 , vital:75301 , https://doi.org/10.1080/10130950.2007.9674885
- Description: This essay was delivered as the annual Shakespeare Birthday Lecture of the Shakespeare Society of Southern Africa in Grahamstown in 2017. It argues that Shakespeare’s predisposition to recognise and develop the dramatic moment turned his initial interest in the normally static and contemplative sonnet into the components of something more like an oratorio of dramatic variations in sonnet form. The author focuses on four sonnets (18, 30, 116, 129) that stake out the thematic and structural range of the whole sequence, and discusses how the poet explores the compositional and indeed architectonic possibilities inherent in the principles and procedures of pursuing ‘variations on a theme’. The sonnets can thus be understood as an ambitious proto-baroque diptych, the two halves of which were to present an elaborate allegory of love versus lust, trust versus deceit, and innocence versus experience.
- Full Text:
- Date Issued: 2018
Addressing constraints in promoting wild edible plants’ utilization in household nutrition: case of the Congo Basin forest area
- Ngome, Precillia Ijang Tata, Shackleton, Charlie M, Degrande, Anne, Tieguhong, Julius Chupezi
- Authors: Ngome, Precillia Ijang Tata , Shackleton, Charlie M , Degrande, Anne , Tieguhong, Julius Chupezi
- Date: 2017
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/60822 , vital:27836 , DOI 10.1186/s40066-017-0097-5
- Description: It is worth raising the question, why are wild edible plants (WEPs) which are rich in diverse nutrients and widely abundant underutilized despite the increasing rate of undernourishment in poor regions? One reason is that their culinary uses are not quantified and standardized in nutrition surveys, and therefore, they are not properly included in household diet intensification and diversification across regions and cultures. Active steps are needed to bridge this gap. This paper outlines the constraints to including WEPs in nutritional surveys as the lack of standard ways of food identification of diverse WEPs, lack of specific food categorization and therefore difficult dissemination across regions and cultures. As a way forward, a functional categorization of 11 subgroups for WEPs is introduced and discussed. In labeling these sub-food groups, the paper advocates that more WEPs food items and culinary uses should be enlisted during household nutrition surveys. Food researchers could then capitalize these enlisted species and disseminate them to promote diverse food use of WEPs in other regions where they exist but are not utilized as food.
- Full Text:
- Date Issued: 2017
- Authors: Ngome, Precillia Ijang Tata , Shackleton, Charlie M , Degrande, Anne , Tieguhong, Julius Chupezi
- Date: 2017
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/60822 , vital:27836 , DOI 10.1186/s40066-017-0097-5
- Description: It is worth raising the question, why are wild edible plants (WEPs) which are rich in diverse nutrients and widely abundant underutilized despite the increasing rate of undernourishment in poor regions? One reason is that their culinary uses are not quantified and standardized in nutrition surveys, and therefore, they are not properly included in household diet intensification and diversification across regions and cultures. Active steps are needed to bridge this gap. This paper outlines the constraints to including WEPs in nutritional surveys as the lack of standard ways of food identification of diverse WEPs, lack of specific food categorization and therefore difficult dissemination across regions and cultures. As a way forward, a functional categorization of 11 subgroups for WEPs is introduced and discussed. In labeling these sub-food groups, the paper advocates that more WEPs food items and culinary uses should be enlisted during household nutrition surveys. Food researchers could then capitalize these enlisted species and disseminate them to promote diverse food use of WEPs in other regions where they exist but are not utilized as food.
- Full Text:
- Date Issued: 2017
Central obesity and normal-weight central obesity among adults attending healthcare facilities in Buffalo City Metropolitan Municipality, South Africa: a cross-sectional study
- Owolabi, Eyitayo Omolara, Ter Goon, Daniel, Adeniyi, Oladele Vincent
- Authors: Owolabi, Eyitayo Omolara , Ter Goon, Daniel , Adeniyi, Oladele Vincent
- Date: 2017
- Subjects: Buffalo City Metropolitan Municipality, South Africa Obesity Central obesity, Overall obesity, Waist circumference, Waist-to-hip ratio, Waist-to-height ratio, NICE BMI-WC composite index, Health risk, Abdominal obesity Computer File
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/5887 , vital:44664 , https://DOI10.1186/s41043-017-0133-x
- Description: Background Central obesity (CO) confers a significant threat on the cardio-metabolic health of individuals, independently of overall obesity. Disparities in the measures of fat distribution lead to misclassification of individuals who are at risk of cardio-metabolic diseases. This study sought to determine the prevalence and correlates of central obesity and normal-weight central obesity among adults attending selected healthcare facilities in Buffalo City Metropolitan Municipality (BCMM), South Africa, assess their health risk and examine the association between central obesity and cardio-metabolic diseases among adults with normal weight, measured by body mass index (BMI). Methods A cross-sectional survey of 998 adults was carried out at the three largest outpatient clinics in BCMM. Overall and central obesity were assessed using BMI, waist circumference (WC), waist-to-hip ratio (WHR) and waist-to-height ratio (WHTR). The WHO STEPwise questionnaire was used for data collection. Blood pressure and blood glucose were measured. Normal-weight central obesity was defined as CO among individuals with normal weight, as assessed by BMI. Health risk levels were assessed using the National Institute for Health and Clinical Excellence (NICE) BMI-WC composite index. Bivariate and multivariate analyses were used to determine the prevalence of CO, normal-weight central obesity and the predictors of CO. Results The mean age of participants was 42.6 (± 16.5) years. The prevalence of CO was 67.0, 58.0 and 71.0% by WC, WHR and WHTR, respectively. The prevalence of normal-weight central obesity was 26.9, 36.9 and 29.5% by WC, WHR and WHTR, respectively. About 41% of the participants had a very high health risk, 13% had increased risk or high risk and 33% had no health risk. Central obesity was significantly associated with hypertension but not associated with diabetes among those with normal weight (by BMI). Female sex, age over 30 years, marriage, secondary or tertiary level of education, non-smoking status, diabetes and hypertension significantly predicted central obesity among the study participants. Conclusion The prevalence of central obesity among the study participants is high, irrespective of the defining criteria. One in three adults of normal weight had central obesity. Body mass index should therefore not be used alone for clinical assessment by healthcare workers in the study setting.
- Full Text:
- Date Issued: 2017
- Authors: Owolabi, Eyitayo Omolara , Ter Goon, Daniel , Adeniyi, Oladele Vincent
- Date: 2017
- Subjects: Buffalo City Metropolitan Municipality, South Africa Obesity Central obesity, Overall obesity, Waist circumference, Waist-to-hip ratio, Waist-to-height ratio, NICE BMI-WC composite index, Health risk, Abdominal obesity Computer File
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/11260/5887 , vital:44664 , https://DOI10.1186/s41043-017-0133-x
- Description: Background Central obesity (CO) confers a significant threat on the cardio-metabolic health of individuals, independently of overall obesity. Disparities in the measures of fat distribution lead to misclassification of individuals who are at risk of cardio-metabolic diseases. This study sought to determine the prevalence and correlates of central obesity and normal-weight central obesity among adults attending selected healthcare facilities in Buffalo City Metropolitan Municipality (BCMM), South Africa, assess their health risk and examine the association between central obesity and cardio-metabolic diseases among adults with normal weight, measured by body mass index (BMI). Methods A cross-sectional survey of 998 adults was carried out at the three largest outpatient clinics in BCMM. Overall and central obesity were assessed using BMI, waist circumference (WC), waist-to-hip ratio (WHR) and waist-to-height ratio (WHTR). The WHO STEPwise questionnaire was used for data collection. Blood pressure and blood glucose were measured. Normal-weight central obesity was defined as CO among individuals with normal weight, as assessed by BMI. Health risk levels were assessed using the National Institute for Health and Clinical Excellence (NICE) BMI-WC composite index. Bivariate and multivariate analyses were used to determine the prevalence of CO, normal-weight central obesity and the predictors of CO. Results The mean age of participants was 42.6 (± 16.5) years. The prevalence of CO was 67.0, 58.0 and 71.0% by WC, WHR and WHTR, respectively. The prevalence of normal-weight central obesity was 26.9, 36.9 and 29.5% by WC, WHR and WHTR, respectively. About 41% of the participants had a very high health risk, 13% had increased risk or high risk and 33% had no health risk. Central obesity was significantly associated with hypertension but not associated with diabetes among those with normal weight (by BMI). Female sex, age over 30 years, marriage, secondary or tertiary level of education, non-smoking status, diabetes and hypertension significantly predicted central obesity among the study participants. Conclusion The prevalence of central obesity among the study participants is high, irrespective of the defining criteria. One in three adults of normal weight had central obesity. Body mass index should therefore not be used alone for clinical assessment by healthcare workers in the study setting.
- Full Text:
- Date Issued: 2017
Customary management as TURFs: social challenges and opportunities
- Authors: Aswani, Shankar
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145403 , vital:38435 , DOI: 10.5343/bms.2015.1084
- Description: There is a growing interest in working with customary management (CM) systems to effectively manage benthic resources and small-scale fisheries. The underlying notion is that CM institution as territorial use rights in fisheries (TURFs) can be sufficiently adaptive and dynamic to create the local incentives that are necessary for promoting sustainable fishing practices and marine conservation more generally in a given region. This paper reviews the social opportunities and challenges of working with CM systems as a form of TURF, particularly in Oceania. A key conclusion is that policy makers and managers not only need to recognize natural interconnectivity in any one marine space, but also consider the social interconnectivity of stakeholders that covers customary TURFs. Only by recognizing and working with the existing social networks that overlay any given marine territory can the operational principles of CM (as reviewed in this paper) be effectively deployed for achieving some kind of bioeconomic efficiency and creating an equitable rights-based fisheries management system.
- Full Text:
- Date Issued: 2017
- Authors: Aswani, Shankar
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145403 , vital:38435 , DOI: 10.5343/bms.2015.1084
- Description: There is a growing interest in working with customary management (CM) systems to effectively manage benthic resources and small-scale fisheries. The underlying notion is that CM institution as territorial use rights in fisheries (TURFs) can be sufficiently adaptive and dynamic to create the local incentives that are necessary for promoting sustainable fishing practices and marine conservation more generally in a given region. This paper reviews the social opportunities and challenges of working with CM systems as a form of TURF, particularly in Oceania. A key conclusion is that policy makers and managers not only need to recognize natural interconnectivity in any one marine space, but also consider the social interconnectivity of stakeholders that covers customary TURFs. Only by recognizing and working with the existing social networks that overlay any given marine territory can the operational principles of CM (as reviewed in this paper) be effectively deployed for achieving some kind of bioeconomic efficiency and creating an equitable rights-based fisheries management system.
- Full Text:
- Date Issued: 2017
Determination of species and instars of the larvae of the Afrotropical species of Thanatophilus Leach, 1817 (Coleoptera, Silphidae)
- Daniel, Claire A, Midgley, John M, Villet, Martin H
- Authors: Daniel, Claire A , Midgley, John M , Villet, Martin H
- Date: 2017
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/59682 , vital:27638 , doi: 10.3897/afrinvertebr.58.12966
- Description: Thanatophilus micans and T. mutilatus have significance for forensic entomology. Their larvae are therefore described and a key is provided for identifying the larvae of Afrotropical Silphidae based on morphological characters. It is shown that seven common species of Thanatophilus can be distinguished by a 360 bp mtDNA sequence from the cytochrome oxidase I gene.
- Full Text:
- Date Issued: 2017
- Authors: Daniel, Claire A , Midgley, John M , Villet, Martin H
- Date: 2017
- Language: English
- Type: article , text
- Identifier: http://hdl.handle.net/10962/59682 , vital:27638 , doi: 10.3897/afrinvertebr.58.12966
- Description: Thanatophilus micans and T. mutilatus have significance for forensic entomology. Their larvae are therefore described and a key is provided for identifying the larvae of Afrotropical Silphidae based on morphological characters. It is shown that seven common species of Thanatophilus can be distinguished by a 360 bp mtDNA sequence from the cytochrome oxidase I gene.
- Full Text:
- Date Issued: 2017
Land cover models to predict non-point nutrient inputs for selected biomes in South Africa
- Slaughter, Andrew R, Mantel, Sukhmani K
- Authors: Slaughter, Andrew R , Mantel, Sukhmani K
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438152 , vital:73439 , ISBN 1816-7950 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/3390.pdf
- Description: WQSAM is a practical water quality model for use in guiding southern African water quality management. However, the estimation of non-point nutrient inputs within WQSAM is uncertain, as it is achieved through a combination of calibration and expert knowledge. Non-point source loads can be correlated to particular land cover types. Although observed water quality data through which non-point source loads can be estimated are scarce, land cover databases exist covering the entire area of South Africa. To reduce the uncertainty associated with estimat-ing non-point source loads, this study describes a formal model to link the nutrient signatures of incremental flow to land cover. Study catch-ments incorporating the fynbos, grassland, savanna and thicket biomes were identified. Instream nutrients of 25 sites were modelled using WQSAM and calibrated against observed data. Multiple regression was used to investigate the relationships between the calibrated nutrient signatures of incremental flow from WQSAM and land cover within study sites. The regression models reflected greater non-point loads from cultivation-and urban-related land cover categories. The nutrient signatures of incremental flow obtained through the multiple regres-sions were consistent with those obtained through calibration of the WQSAM model at higher signature values, whereas discrepancies were evident at lower values. It is argued that this formal modelling ap-proach for linking land cover to nutrient signatures of incremental flow can be implemented for situations where it is known that there are strong non-point inputs of nutrients into a river reach. The statistical model presented in the current study could potentially be applied as an alternative to the water quality model as a relatively simple method to estimate non-point source loads of nutrients from tributary catchments in South Africa.
- Full Text:
- Date Issued: 2017
- Authors: Slaughter, Andrew R , Mantel, Sukhmani K
- Date: 2017
- Subjects: To be catalogued
- Language: English
- Type: text , report
- Identifier: http://hdl.handle.net/10962/438152 , vital:73439 , ISBN 1816-7950 , https://wrcwebsite.azurewebsites.net/wp-content/uploads/mdocs/3390.pdf
- Description: WQSAM is a practical water quality model for use in guiding southern African water quality management. However, the estimation of non-point nutrient inputs within WQSAM is uncertain, as it is achieved through a combination of calibration and expert knowledge. Non-point source loads can be correlated to particular land cover types. Although observed water quality data through which non-point source loads can be estimated are scarce, land cover databases exist covering the entire area of South Africa. To reduce the uncertainty associated with estimat-ing non-point source loads, this study describes a formal model to link the nutrient signatures of incremental flow to land cover. Study catch-ments incorporating the fynbos, grassland, savanna and thicket biomes were identified. Instream nutrients of 25 sites were modelled using WQSAM and calibrated against observed data. Multiple regression was used to investigate the relationships between the calibrated nutrient signatures of incremental flow from WQSAM and land cover within study sites. The regression models reflected greater non-point loads from cultivation-and urban-related land cover categories. The nutrient signatures of incremental flow obtained through the multiple regres-sions were consistent with those obtained through calibration of the WQSAM model at higher signature values, whereas discrepancies were evident at lower values. It is argued that this formal modelling ap-proach for linking land cover to nutrient signatures of incremental flow can be implemented for situations where it is known that there are strong non-point inputs of nutrients into a river reach. The statistical model presented in the current study could potentially be applied as an alternative to the water quality model as a relatively simple method to estimate non-point source loads of nutrients from tributary catchments in South Africa.
- Full Text:
- Date Issued: 2017
Phototransferred thermoluminescence of α-Al2O3: C: experimental results and empirical models
- Chithambo, Makaiko L, Seneza, Cleophace, Kalita, Jitumani M
- Authors: Chithambo, Makaiko L , Seneza, Cleophace , Kalita, Jitumani M
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/115681 , vital:34215 , https://doi.org/10.1016/j.radmeas.2017.08.009
- Description: The thermoluminescence glow curve of α-Al2O3:C consists of a prominent apparently-single peak and a number of weaker intensity secondary peaks. Phototransferred thermoluminescence (PTTL) from secondary glow peaks in α-Al2O3:C is reported. For completeness and to aid discussion, complementary results for the main peak are included. The problem studied is one of phototransferred thermoluminescence for a system of multiple acceptors and multiple donors. A TL glow curve recorded at 5 °C/s following irradiation to 0.5 Gy shows the main peak (labelled II) at 240 °C and two secondary peaks at 86 °C (peak I) and 360 °C (peak III). Peak I is reproduced under phototransfer after any preheating between 100 and 500 °C. Peak II is also reproduced as a PTTL peak after preheating to any temperature up to 800 °C. For the latter, the duration of preheating matters because if the sample is preheated at 800 °C for say, 6 min, PTTL is obtained but not when this is extended to say, 15 min. No PTTL was observed from peak III at all. A study of the time dependence of the PTTL intensity from peak III, following preheating that removes peaks I and II, shows that its electron trap acts as an acceptor when the duration of illumination to stimulate electrons from deep traps is brief but that when the illumination time is extended, the electron trap for peak III loses some of its trapped electrons to the shallower traps thus acting as a donor trap.
- Full Text: false
- Date Issued: 2017
- Authors: Chithambo, Makaiko L , Seneza, Cleophace , Kalita, Jitumani M
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/115681 , vital:34215 , https://doi.org/10.1016/j.radmeas.2017.08.009
- Description: The thermoluminescence glow curve of α-Al2O3:C consists of a prominent apparently-single peak and a number of weaker intensity secondary peaks. Phototransferred thermoluminescence (PTTL) from secondary glow peaks in α-Al2O3:C is reported. For completeness and to aid discussion, complementary results for the main peak are included. The problem studied is one of phototransferred thermoluminescence for a system of multiple acceptors and multiple donors. A TL glow curve recorded at 5 °C/s following irradiation to 0.5 Gy shows the main peak (labelled II) at 240 °C and two secondary peaks at 86 °C (peak I) and 360 °C (peak III). Peak I is reproduced under phototransfer after any preheating between 100 and 500 °C. Peak II is also reproduced as a PTTL peak after preheating to any temperature up to 800 °C. For the latter, the duration of preheating matters because if the sample is preheated at 800 °C for say, 6 min, PTTL is obtained but not when this is extended to say, 15 min. No PTTL was observed from peak III at all. A study of the time dependence of the PTTL intensity from peak III, following preheating that removes peaks I and II, shows that its electron trap acts as an acceptor when the duration of illumination to stimulate electrons from deep traps is brief but that when the illumination time is extended, the electron trap for peak III loses some of its trapped electrons to the shallower traps thus acting as a donor trap.
- Full Text: false
- Date Issued: 2017
Situating Africa: an alter-geopolitics of knowledge, or Chapungu rises
- Authors: Simbao, Ruth K
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146112 , vital:38496 , https://0-doi.org.wam.seals.ac.za/10.1162/AFAR_a_00340
- Description: This journal issue marks the beginning of a new partnership with African Arts as Rhodes University in Grahamstown, South Africa, joins the editorial consortium. As the National Research Foundation Chair in Geopolitics and the Arts of Africa, I will work with collaborators based largely on the African continent to produce one issue of African Arts per year. This first issue has grown out of conversations with artists, curators, and writers based in Uganda, Zimbabwe, and South Africa at a publishing workshop organized by Rhodes University, as well as an institutional collaboration with Makerere University in Uganda. It also includes a dialogue with colleagues in Tanzania, Zambia, Nigeria, Egypt, South Africa, Benin, the Democratic Republic of Congo, Zimbabwe, the US, Uganda, and Angola/Portugal. A core goal of our work is to significantly increase the participation of authors based on the African continent as a way of strengthening our discipline with a scholarly approach that takes seriously an alter-geopolitics of knowledge as a decolonial concept (Koopman 2011; Mignolo 2002).
- Full Text:
- Date Issued: 2017
- Authors: Simbao, Ruth K
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/146112 , vital:38496 , https://0-doi.org.wam.seals.ac.za/10.1162/AFAR_a_00340
- Description: This journal issue marks the beginning of a new partnership with African Arts as Rhodes University in Grahamstown, South Africa, joins the editorial consortium. As the National Research Foundation Chair in Geopolitics and the Arts of Africa, I will work with collaborators based largely on the African continent to produce one issue of African Arts per year. This first issue has grown out of conversations with artists, curators, and writers based in Uganda, Zimbabwe, and South Africa at a publishing workshop organized by Rhodes University, as well as an institutional collaboration with Makerere University in Uganda. It also includes a dialogue with colleagues in Tanzania, Zambia, Nigeria, Egypt, South Africa, Benin, the Democratic Republic of Congo, Zimbabwe, the US, Uganda, and Angola/Portugal. A core goal of our work is to significantly increase the participation of authors based on the African continent as a way of strengthening our discipline with a scholarly approach that takes seriously an alter-geopolitics of knowledge as a decolonial concept (Koopman 2011; Mignolo 2002).
- Full Text:
- Date Issued: 2017
A case study on the health risks related to flood disasters in South Africa
- Tandlich, Roman, Ncube, Mbonisi, Khamanga, Sandile M, Zuma, Bongumusa M
- Authors: Tandlich, Roman , Ncube, Mbonisi , Khamanga, Sandile M , Zuma, Bongumusa M
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/75917 , vital:30482 , DOI: 10.20965/jdr.2016.p0732
- Description: Floods occurred in the Ndlambe Local Municipality in South Africa in October 2012. During various stages of the post-disaster recovery, bacterial concentrations were measured in water and soil samples from the flood zone. All drinking water concentrations of E. coli were below 1–3 colony forming units per 100 millilitres (CFUs/100 mL). The flood waters contained between 46500 to more than 100000 CFUs/100 mL of E. coli. {The concentrations of Salmonella spp. in the flood waters varied from 5000 to 250000 CFUs/100 mL. The presumptive Vibrio spp. concentrations in flood waters ranged from 1000 to over 150000 CFUs/100 mL. {The soil concentrations for E. coli ranged from 1 to above 330 colony-forming units per 1 g of soil dry weight (CFUs/g). The soil concentrations of Salmonella spp. varied from below 1 to 22 CFUs/g. The estimated airborne fungal concentrations ranged from 16820 to 28540 colony-forming units per 1 cubic meter. An outbreak of an infectious disease was recorded among the volunteers who assisted with the post-disaster recovery. The likely bacterial causative agents included strains of Aeromonas spp. and Vibrio cholerae. Any human contact with either the contaminated flood waters or of flooded dwellings should only occur, if the individuals in questions are equipped with the full-body personal protective gear. Non-governmental stakeholders performed majority of the post-disaster recovery operations, as the local government could only cover 11% of the required costs. Applying sanitation funds to disaster recovery and increased use of the low-cost flood defence products in high risk areas could provide a solution for the future.
- Full Text: false
- Date Issued: 2016
- Authors: Tandlich, Roman , Ncube, Mbonisi , Khamanga, Sandile M , Zuma, Bongumusa M
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/75917 , vital:30482 , DOI: 10.20965/jdr.2016.p0732
- Description: Floods occurred in the Ndlambe Local Municipality in South Africa in October 2012. During various stages of the post-disaster recovery, bacterial concentrations were measured in water and soil samples from the flood zone. All drinking water concentrations of E. coli were below 1–3 colony forming units per 100 millilitres (CFUs/100 mL). The flood waters contained between 46500 to more than 100000 CFUs/100 mL of E. coli. {The concentrations of Salmonella spp. in the flood waters varied from 5000 to 250000 CFUs/100 mL. The presumptive Vibrio spp. concentrations in flood waters ranged from 1000 to over 150000 CFUs/100 mL. {The soil concentrations for E. coli ranged from 1 to above 330 colony-forming units per 1 g of soil dry weight (CFUs/g). The soil concentrations of Salmonella spp. varied from below 1 to 22 CFUs/g. The estimated airborne fungal concentrations ranged from 16820 to 28540 colony-forming units per 1 cubic meter. An outbreak of an infectious disease was recorded among the volunteers who assisted with the post-disaster recovery. The likely bacterial causative agents included strains of Aeromonas spp. and Vibrio cholerae. Any human contact with either the contaminated flood waters or of flooded dwellings should only occur, if the individuals in questions are equipped with the full-body personal protective gear. Non-governmental stakeholders performed majority of the post-disaster recovery operations, as the local government could only cover 11% of the required costs. Applying sanitation funds to disaster recovery and increased use of the low-cost flood defence products in high risk areas could provide a solution for the future.
- Full Text: false
- Date Issued: 2016
Binding and entry of a non-enveloped T=4 insect RNA virus is triggered by alkaline pH
- Penkler, David L, Jiwaji, Meesbah, Domitrovic, Tatiana, Short, James R, Johnson, John E, Dorrington, Rosemary A
- Authors: Penkler, David L , Jiwaji, Meesbah , Domitrovic, Tatiana , Short, James R , Johnson, John E , Dorrington, Rosemary A
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/65995 , vital:28875 , https://doi.org/10.1016/j.virol.2016.08.028
- Description: publisher version , Tetraviruses are small, non-enveloped, RNA viruses that exclusively infect lepidopteran insects. Their particles comprise 240 copies of a single capsid protein precursor (CP), which undergoes autoproteolytic cleavage during maturation. The molecular mechanisms of capsid assembly and maturation are well understood, but little is known about the viral infectious lifecycle due to a lack of tissue culture cell lines that are susceptible to tetravirus infection. We show here that binding and entry of the alphatetravirus, Helicoverpa armigera stunt virus (HaSV), is triggered by alkaline pH. At pH 9.0, wild-type HaSV virus particles undergo conformational changes that induce membrane-lytic activity and binding to Spodoptera frugiperda Sf9 cells. Binding is followed by entry and infection, with virus replication complexes detected by immunofluorescence microscopy within 2 h post-infection and the CP after 12 h. HaSV particles produced in S. frugiperda Sf9 cells are infectious. Helicoverpa armigera larval virus biofeed assays showed that pre-treatment with the V-ATPase inhibitor, Bafilomycin A1, resulted in a 50% decrease in larval mortality and stunting, while incubation of virus particles at pH 9.0 prior to infection restored infectivity. Together, these data show that HaSV, and likely other tetraviruses, requires the alkaline environment of the lepidopteran larval midgut for binding and entry into host cells.
- Full Text: false
- Date Issued: 2016
- Authors: Penkler, David L , Jiwaji, Meesbah , Domitrovic, Tatiana , Short, James R , Johnson, John E , Dorrington, Rosemary A
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/65995 , vital:28875 , https://doi.org/10.1016/j.virol.2016.08.028
- Description: publisher version , Tetraviruses are small, non-enveloped, RNA viruses that exclusively infect lepidopteran insects. Their particles comprise 240 copies of a single capsid protein precursor (CP), which undergoes autoproteolytic cleavage during maturation. The molecular mechanisms of capsid assembly and maturation are well understood, but little is known about the viral infectious lifecycle due to a lack of tissue culture cell lines that are susceptible to tetravirus infection. We show here that binding and entry of the alphatetravirus, Helicoverpa armigera stunt virus (HaSV), is triggered by alkaline pH. At pH 9.0, wild-type HaSV virus particles undergo conformational changes that induce membrane-lytic activity and binding to Spodoptera frugiperda Sf9 cells. Binding is followed by entry and infection, with virus replication complexes detected by immunofluorescence microscopy within 2 h post-infection and the CP after 12 h. HaSV particles produced in S. frugiperda Sf9 cells are infectious. Helicoverpa armigera larval virus biofeed assays showed that pre-treatment with the V-ATPase inhibitor, Bafilomycin A1, resulted in a 50% decrease in larval mortality and stunting, while incubation of virus particles at pH 9.0 prior to infection restored infectivity. Together, these data show that HaSV, and likely other tetraviruses, requires the alkaline environment of the lepidopteran larval midgut for binding and entry into host cells.
- Full Text: false
- Date Issued: 2016
Characterization and Analysis of NTP Amplifier Traffic
- Rudman, Lauren, Irwin, Barry V W
- Authors: Rudman, Lauren , Irwin, Barry V W
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429482 , vital:72616 , 10.23919/SAIEE.2016.8531542
- Description: Network Time Protocol based DDoS attacks saw a lot of popularity throughout 2014. This paper shows the characterization and analysis of two large datasets containing packets from NTP based DDoS attacks captured in South Africa. Using a series of Python based tools, the dataset is analysed according to specific parts of the packet headers. These include the source IP address and Time-to-Live (TTL) values. The analysis found the top source addresses and looked at the TTL values observed for each address. These TTL values can be used to calculate the probable operating system or DDoS attack tool used by an attacker. We found that each TTL value seen for an address can indicate the number of hosts attacking the address or indicate minor routing changes. The Time-to-Live values are then analysed as a whole to find the total number used throughout each attack. The most frequent TTL values are then found and show that the majority of them indicate the attackers are using an initial TTL of 255. This value can indicate the use of a certain DDoS tool that creates packets with that exact initial TTL. The TTL values are then put into groups that can show the number of IP addresses a group of hosts are targeting. The paper discusses our work with two brief case studies correlating observed data to real-world attacks, and the observable impact thereof.
- Full Text:
- Date Issued: 2016
- Authors: Rudman, Lauren , Irwin, Barry V W
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/429482 , vital:72616 , 10.23919/SAIEE.2016.8531542
- Description: Network Time Protocol based DDoS attacks saw a lot of popularity throughout 2014. This paper shows the characterization and analysis of two large datasets containing packets from NTP based DDoS attacks captured in South Africa. Using a series of Python based tools, the dataset is analysed according to specific parts of the packet headers. These include the source IP address and Time-to-Live (TTL) values. The analysis found the top source addresses and looked at the TTL values observed for each address. These TTL values can be used to calculate the probable operating system or DDoS attack tool used by an attacker. We found that each TTL value seen for an address can indicate the number of hosts attacking the address or indicate minor routing changes. The Time-to-Live values are then analysed as a whole to find the total number used throughout each attack. The most frequent TTL values are then found and show that the majority of them indicate the attackers are using an initial TTL of 255. This value can indicate the use of a certain DDoS tool that creates packets with that exact initial TTL. The TTL values are then put into groups that can show the number of IP addresses a group of hosts are targeting. The paper discusses our work with two brief case studies correlating observed data to real-world attacks, and the observable impact thereof.
- Full Text:
- Date Issued: 2016
Developmental and spatial variations in the diet signatures of hyperbenthic shrimp Nauticaris marionis at the Prince Edward Islands based on stable isotope ratios and fatty acid profiles
- Richoux, Nicole B, Allan, E Louise, Froneman, P William
- Authors: Richoux, Nicole B , Allan, E Louise , Froneman, P William
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67923 , vital:29169 , https://doi.org/10.1016/j.csr.2016.02.0131
- Description: Publisher version , The caridean shrimp Nauticaris marionis is an ecologically important species in the benthic community around the sub-Antarctic Prince Edward Islands (PEI) as it represents a key prey item for a variety of top predators breeding on the islands. We hypothesized that the diet of N. marionis shifts during its development, and that spatial variability in food availability results in differentiation in the diet signatures of specimens collected from various locations of the shelf waters around the PEI. Specimens were collected from nine stations (depth range 70 to 240 m) around the PEI at inter-island shelf (from west to east: upstream, between and downstream) and nearshore regions during austral autumn 2009. Stable isotope and fatty acid data both revealed spatial and developmental variations in the shrimp diet. Nearshore shrimp were more 13C-enriched than those from the inter-island region, suggesting increased kelp detritus entered the food web in the nearshore regions. The shrimp showed increases in δ13C and δ15N signatures (and trophic position) with an increase in body size, resulting in distinctions between size classes that reflected shifts in their trophic niche through development. The fatty acid profiles similarly indicated distinctions in diet with increased shrimp size (in the deep regions), and spatial variability was evident in relation to region and depth. All shrimp contained large proportions of polyunsaturated and essential fatty acids, indicating that the quality of food consumed was similar between regions despite the diet variability. Our results provide new dietary information about a key species operating near the base of the food web at the highly productive PEI, and show that there were no areas of enhanced nutrition available to the shrimp. As such, there was no nutritional advantage to shrimp inhabiting any specific region around the PEI.
- Full Text: false
- Date Issued: 2016
- Authors: Richoux, Nicole B , Allan, E Louise , Froneman, P William
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67923 , vital:29169 , https://doi.org/10.1016/j.csr.2016.02.0131
- Description: Publisher version , The caridean shrimp Nauticaris marionis is an ecologically important species in the benthic community around the sub-Antarctic Prince Edward Islands (PEI) as it represents a key prey item for a variety of top predators breeding on the islands. We hypothesized that the diet of N. marionis shifts during its development, and that spatial variability in food availability results in differentiation in the diet signatures of specimens collected from various locations of the shelf waters around the PEI. Specimens were collected from nine stations (depth range 70 to 240 m) around the PEI at inter-island shelf (from west to east: upstream, between and downstream) and nearshore regions during austral autumn 2009. Stable isotope and fatty acid data both revealed spatial and developmental variations in the shrimp diet. Nearshore shrimp were more 13C-enriched than those from the inter-island region, suggesting increased kelp detritus entered the food web in the nearshore regions. The shrimp showed increases in δ13C and δ15N signatures (and trophic position) with an increase in body size, resulting in distinctions between size classes that reflected shifts in their trophic niche through development. The fatty acid profiles similarly indicated distinctions in diet with increased shrimp size (in the deep regions), and spatial variability was evident in relation to region and depth. All shrimp contained large proportions of polyunsaturated and essential fatty acids, indicating that the quality of food consumed was similar between regions despite the diet variability. Our results provide new dietary information about a key species operating near the base of the food web at the highly productive PEI, and show that there were no areas of enhanced nutrition available to the shrimp. As such, there was no nutritional advantage to shrimp inhabiting any specific region around the PEI.
- Full Text: false
- Date Issued: 2016
Indolyl-3-ethanone-α-thioethers: a promising new class of non-toxic antimalarial agents
- Svogie, Archibald L, Isaacs, Michelle, Hoppe, Heinrich C, Khanye, Setshaba D, Veale, Clinton G L
- Authors: Svogie, Archibald L , Isaacs, Michelle , Hoppe, Heinrich C , Khanye, Setshaba D , Veale, Clinton G L
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66233 , vital:28920 , https://doi.org/10.1016/j.ejmech.2016.02.056
- Description: publisher version , The success of chemotherapeutics in easing the burden of malaria is under continuous threat from ever-evolving parasite resistance, including resistance to artemisinin combination therapies. Therefore, the discovery of new classes of antimalarials which inhibit new biological targets is imperative to controlling malaria. Accordingly, we report here the discovery of indolyl-3-ethanone-α-thioethers, a new class of antimalarial compounds with encouraging activity. Synthesis of a focused library of compounds revealed important insight into the SAR of this class of compounds, including critical information regarding the position and chemical nature of substituents on both the thiophenol and indole rings. This investigation ultimately led to the discovery of two hit compounds (16 and 27) which exhibited nano molar in vitro antimalarial activity coupled to no observable toxicity against a HeLa cell line.
- Full Text: false
- Date Issued: 2016
- Authors: Svogie, Archibald L , Isaacs, Michelle , Hoppe, Heinrich C , Khanye, Setshaba D , Veale, Clinton G L
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66233 , vital:28920 , https://doi.org/10.1016/j.ejmech.2016.02.056
- Description: publisher version , The success of chemotherapeutics in easing the burden of malaria is under continuous threat from ever-evolving parasite resistance, including resistance to artemisinin combination therapies. Therefore, the discovery of new classes of antimalarials which inhibit new biological targets is imperative to controlling malaria. Accordingly, we report here the discovery of indolyl-3-ethanone-α-thioethers, a new class of antimalarial compounds with encouraging activity. Synthesis of a focused library of compounds revealed important insight into the SAR of this class of compounds, including critical information regarding the position and chemical nature of substituents on both the thiophenol and indole rings. This investigation ultimately led to the discovery of two hit compounds (16 and 27) which exhibited nano molar in vitro antimalarial activity coupled to no observable toxicity against a HeLa cell line.
- Full Text: false
- Date Issued: 2016