Local perceptions of environmental changes in fishing communities of southwest Madagascar:
- Authors: Lemahieu, Anne , Scott, Lucy E P , Malherbe, Willem , Mahatante, Paubert T , Randrianarimanana, José V , Aswani, Shankar
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/145370 , vital:38432 , DOI: 10.1016/j.ocecoaman.2018.06.012
- Description: Southwest Madagascar is a region that is significantly impacted upon by climate change. As in a lot of developing countries, the livelihoods of many communities in this region are dependent on fishing. This makes these communities particularly vulnerable to climate-related changes. We conducted a survey in two coastal fishing communities in the Toliara Province, Ambola and Ambotsibotsike. Using a free listing exercise, semi-structured interviews and focus group methods, we documented local perceptions of environmental changes and responses to changes. Results were compared, taking into account the differences in the degree of remoteness, market exposure and religiosity. Time periods that respondents reported as having had a high degree of change were compared to time periods of historical records of cyclones occurring in Toliara Province.
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Low symmetric metallophthalocyanine modified electrode via click chemistry for simultaneous detection of heavy metals
- Authors: Fomo, Gertrude , Nwaji, Njemuwa , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/187914 , vital:44709 , xlink:href="https://doi.org/10.1016/j.jelechem.2018.02.016"
- Description: Beside different methods and materials used to develop electrochemical sensors, the modification of the electrode using click reaction based on metallophthalocyanine (MPc) compounds are shown to improve the stability and sensitivity of the sensor. This work reported the development of electrochemical sensor for mercury (II), Lead (II), copper (II) and cadmium (II) ions detection based on the synthesized novel low symmetry alkyne terminated cobalt Phthalocyanine (CoPc) derivative. Differential pulse stripping voltammetry (DPSV) technique was employed for the first time in simultaneous determination of trace levels of the above metal ions using modified glassy carbon electrode (GCE) via click chemistry. Under the optimum experimental conditions, the anodic peak current is proportional to the concentrations of metal ions over a wide range of 0 to 0.1 mM with nanolevel detection limit of 81.94, 327.71, 55.87 and 347.06 nM and the sensitivity of 866.23 ± 5.48, 215.82 ± 2.16, 1979.48 ± 11.47 and 204.50 ± 1.10 μA/mM for Hg(II), Cu(II), Pb(II) and Cd(II), respectively. The selectivity of the clicked-CoPc modified GCE toward Hg(II), Cu(II), Pb(II), Cd(II) present no interference from these metals ions. The fabricated electrochemical sensor exhibited very good electrochemical properties such as good reproducibility, stability, reusability and is suitable for the detection of heavy metal ions in tap water in our laboratory.
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LRP1 is required for novobiocin-mediated fibronectin turnover:
- Authors: Boel, Natasha M-E , Hunter, Morgan C , Edkins, Adrienne L
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/164896 , vital:41182 , DOI: 10.1038/s41598-018-29531-2
- Description: Fibronectin (FN) plays a major role in the stability and organization of the extracellular matrix (ECM). We have previously demonstrated that FN interacts directly with Hsp90, as well as showing that the Hsp90 inhibitor novobiocin results in FN turnover via a receptor mediated process. However, the receptor involved has not been previously identified. LRP1 is a ubiquitous receptor responsible for the internalisation of numerous ligands that binds both Hsp90 and FN, and therefore we investigated whether LRP1 was involved in novobiocin-mediated FN turnover.
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Major security incidents since 2014: an African perspective
- Authors: Van Heerden, Renier , Von Solms, Sune , Vorster, Johannes
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68291 , vital:29234 , https://ieeexplore.ieee.org/abstract/document/8417326/
- Description: Publisher version , The integration of technology in the modern society provides many benefits, but with increased connectivity comes increased risk where governments, businesses and individuals are vulnerable to a variety of cyber-attacks. Many of the large information security attacks of the last decade can be seen as an attack on 'foreign” systems or individuals when viewed from an African perspective, with no direct impact on an individual in Africa. However, information security experts in Africa states that although some of these attacks might not have had a direct impact of the African individual, but never the less should not be ignored as it does indirectly influence the African individual. The experts state that even if the individuals or businesses are not directly influenced by an attack, it should not be ignored as similar attacks might influence them in the future. They emphasise that these attacks should improve their cybersecurity awareness and behaviour, in order to prevent similar attacks from impacting them.
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Mapping the field of Higher Education Research using PhD examination reports
- Authors: McKenna, Sioux , Quinn, Lynn , Vorster, Jo-Anne
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66669 , vital:28979 , ISSN 1469-8366 , https://doi.org/10.1080/07294360.2018.1428178
- Description: Pre-print , The PhD is the highest formal qualification and signifies a scholar’s rite of passage as a legitimate contributor of new knowledge in a field. Examiner reports make claims about what is legitimate in a thesis and what is not and thus articulate the organising principles through which participation in a field is measured. The authors analysed 39 examiners’ reports on 13 PhDs produced over a five-year period by scholars from the Higher Education Research doctoral studies programme at Rhodes University in South Africa. Drawing on aspects of Karl Maton’s Legitimation Code Theory (LCT), this study uses the dimensions of LCT:Specialisation and LCT:Semantics to explore what kinds of knowledge, skills and procedures and what kinds of knowers are validated in the field of Higher Education Research through the examination process. The study found that despite concerns in the literature about the a-theoretical nature of the Higher Education Studies field, examiners valued high-level theoretical and meta-theoretical engagement as well as methodological rigour. In addition, examiners prized the ability to demonstrate a strong ideological position, to use a clear doctoral voice, and to recognise the axiological drive of the field. The analysis showed that examiners were interested in strong contextualisation of the problem-spaces in higher education in South Africa but also commented positively on candidates’ ability to move from troubling an issue within its context to being able to abstract findings so as to contribute to the field as a whole.
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Marine resource management and conservation in the Anthropocene
- Authors: Aswani, Shankar , Basurto, Xavier , Ferse, Sebastian , Glaser, Marion , Campbell, Lisa , Cinner, Joshua E , Dalton, Tracey , Jenkins, Lekelia D , Miller, Marc L , Pollnac, Richard , McGill University , Christie, Patrick
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124987 , vital:35716 , https://doi.10.1017/S0376892917000431
- Description: Because the Anthropocene by definition is an epoch during which environmental change is largely anthropogenic and driven by social, economic, psychological and political forces, environmental social scientists can effectively analyse human behaviour and knowledge systems in this context. In this subject review, we summarize key ways in which the environmental social sciences can better inform fisheries management policy and practice and marine conservation in the Anthropocene. We argue that environmental social scientists are particularly well positioned to synergize research to fill the gaps between: (1) local behaviours/needs/worldviews and marine resource management and biological conservation concerns; and (2) large-scale drivers of planetary environmental change (globalization, affluence, technological change, etc.) and local cognitive, socioeconomic, cultural and historical processes that shape human behaviour in the marine environment. To illustrate this, we synthesize the roles of various environmental social science disciplines in better understanding the interaction between humans and tropical marine ecosystems in developing nations where issues arising from human–coastal interactions are particularly pronounced. We focus on: (1) the application of the environmental social sciences in marine resource management and conservation; (2) the development of ‘new’ socially equitable marine conservation; (3) repopulating the seascape; (4) incorporating multi-scale dynamics of marine social–ecological systems; and (5) envisioning the future of marine resource management and conservation for producing policies and projects for comprehensive and successful resource management and conservation in the Anthropocene.
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Mbeki's African Renaissance Vision as Reflected in isiXhosa Written Poetry: 2005–2011
- Authors: Mona, Godfrey V , Kaschula, Russell H
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/174705 , vital:42502 , ttps://doi.org/10.1080/18186874.2018.1457616
- Description: IsiXhosa literary critics have not yet interrogated literature that was produced during and after the tenure of Thabo Mvuyelwa Mbeki as deputy president and president of the Republic of South Africa in order to study the impact of his African Renaissance doctrine. This article analyses poetry that was produced from 2005 to 2011. The content of the isiXhosa written poetry is profoundly influenced by the context of former President Mbeki's African Renaissance philosophy, its implementation structures and philosophy of self-confidence and self-reliance. The selected poems analysed and interpreted in this article suggest that Mbeki's legacy of the African Renaissance empowered poets to develop a narrative that advances the building of a regenerated South African nation and the African continent.
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Mechanisms and indicators for assessing the impact of biofuel feedstock production on ecosystem services
- Authors: Gasparatos, Alexandros , Romeu-Dalmau, Carla , von Maltitz, Graham P , Johnson, Francis X , Shackleton, Charlie M , Jarzebski, Marcin P , Jumbe, Charles , Ochieng, Caroline , Mudombi, Shakespear , Nyambane, Anne , Willis, Katherine J
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/181368 , vital:43727 , xlink:href="https://doi.org/10.1016/j.biombioe.2018.01.024"
- Description: Biofuel feedstock production can be a significant driver of landscape modification, ecosystem change and biodiversity loss. There is growing body of literature that shows how biofuel landscapes provide various ecosystem services (e.g., feedstock for fuel, carbon sequestration) and compromise other ecosystem services (e.g., food, freshwater services). These effects are context-specific and depend largely on prior land use conditions and feedstock production practices. Changes in the flow of ecosystem services due to the conversion of natural and agricultural areas can have ripple effects on human wellbeing. Despite some recent attempts to apply to biofuel settings concepts and methods rooted in the ecosystem services literature, this is the exception rather than the rule within both the biofuel and the ecosystem services research communities. This paper synthesizes the current knowledge about the impact of biofuels on ecosystem services. It focuses especially on the feedstock production phase and outlines the main mechanisms through which landscape conversion affects the provisions of ecosystem services. It proposes conceptually coherent indicators to reflect these mechanisms and offers a critical discussion of key issues at the interface of biofuels and ecosystem services.
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Metabolic activity throughout early development of dusky kob Argyrosomus japonicus (Sciaenidae)
- Authors: Edworthy, Carla , James, Nicola C , Erasmus, B , Kemp, J O G , Kaiser, Horst , Potts, Warren M
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125159 , vital:35737 , https://doi.10.2989/1814232x.2018.1441907
- Description: Metabolism quantifies the energy-consuming activities of an organism (Nelson 2016) and is used as an indication of how organisms partition energy resources to activities that allow them to survive, grow and reproduce (Post and Lee 1996). The metabolic profile, which is a composition of the various metabolic rates of an individual, therefore gives an indication of the efficiency of energy transformation and allocation (Fry 1971; Brown et al. 2004). McKenzie et al. (2016) suggested that an organism’s physiology contributes towards its ability to survive under specific environmental conditions. As a result, physiological condition can be a reflection of the performance and fitness of an organism (Pörtner 2010). When combined with information on changing environmental conditions, physiological information can provide insight into species- and community-level responses (Pörtner and Farrell 2008). These kinds of data have served numerous ecological applications, including resource management, conservation (McKenzie et al. 2016) and climate-change assessments (Pörtner and Farrell 2008).
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MODE-TASK: Large-scale protein motion tools
- Authors: Ross, Caroline J , Nizami, B , Glenister, M , Amamuddy, Olivier S , Atilgan, Ali R , Atilgan, Canan , Tastan Bishop, Özlem
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125206 , vital:35746 , http://dx.doi.org/10.1101/217505
- Description: Conventional analysis of molecular dynamics (MD) trajectories may not identify global motions of macromolecules. Normal Mode Analysis (NMA) and Principle Component Analysis (PCA) are two popular methods to quantify large-scale motions, and find the “essential motions”; and have been applied to problems such as drug resistant mutations (Nizami et al., 2016) and viral capsid expansion (Hsieh et al., 2016). MODE-TASK is an array of tools to analyse and compare protein dynamics obtained from MD simulations and/or coarse grained elastic network models. Users may perform standard PCA, kernel and incremental PCA (IPCA). Data reduction techniques (Multidimensional Scaling (MDS) and t-Distributed Stochastics Neighbor Embedding (t-SNE)) are implemented. Users may analyse normal modes by constructing elastic network models (ENMs) of a protein complex. A novel coarse graining approach extends its application to large biological assemblies.
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Modulation of human Hsp90α conformational dynamics by allosteric ligand interaction at the c-terminal domain:
- Authors: Penkler, David L , Tastan Bishop, Özlem
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/148402 , vital:38736 , DOI: 10.1101/386755
- Description: Recent years have seen heat shock protein 90 kDa (Hsp90) attract significant interest as a viable drug target, particularly for cancer. To date, designed inhibitors that target the ATPase domain demonstrate potent anti-proliferative effects, but have failed clinical trials due to high levels of associated toxicity. To circumvent this, the focus has shifted away from the ATPase domain. One option involves modulation of the protein through allosteric activation/inhibition. Here, we propose a novel approach: we use previously obtained information via residue perturbation scanning coupled with dynamic residue network analysis to identify allosteric drug targeting sites for inhibitor docking.
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More than just fields: Reframing deagrarianisation in landscapes and livelihoods
- Authors: Hebinck, Paul , Mtati, Nosiseko , Shackleton, Charlie M
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180322 , vital:43353 , xlink:href="https://doi.org/10.1016/j.jrurstud.2018.01.004"
- Description: This paper discusses the emergent properties of deagrarianisation processes in two villages in the central Eastern Cape, South Africa. The claim of is that much of the deagrarianisation literature and debate does not acknowledge the importance of landscapes and the interaction between their constituent elements, notably people, forests, grasslands, fields, grazing lands, open spaces, built environments and homesteads, all of which contribute to shaping and, in turn, are shaped by livelihoods. Conceptualising a landscape as a spatial entity and associated assemblage of practices, discourses and history, this paper dissects the landscape in terms of land uses for residential and cultural purposes, growing, grazing and gathering. These land use categories together represent the rural domain to which the villagers are attached as a place and a home. Their use of the land is not necessarily oriented to fully exploring its productive potential. The article explores the transformation from a productive landscape to one which largely hinges on consumption. The blurring of boundaries between the formally designated land use categories signifies the transformations occurring in many of the rural areas in the former homelands of South Africa.
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Morphological, genetic and biological characterisation of a novel alphabaculovirus isolated from Cryptophlebia peltastica (Lepidoptera: Tortricidae)
- Authors: Marsberg, Tamryn , Jukes, Michael , Krejmer-Rabalska, Martyna , Rabalski, Lukasz , Knox, Caroline , Moore, Sean D , Hill, Martin P , Szewczyk, Boguslaw
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/419330 , vital:71635 , xlink:href="https://doi.org/10.1016/j.jip.2018.08.006"
- Description: Cryptophlebia peltastica is an agricultural pest of litchis and macadamias in South Africa with phytosanitary status for certain markets. Current control methods rely on chemical, cultural and classical biological control. However, a microbial control option has not been developed. An Alphabaculovirus from C. peltastica was recovered from a laboratory reared colony and morphologically characterised by transmission electron microscopy (TEM). Analysis of occlusion bodies indicated a single NPV (SNPV) varying in size from 421 to 1263 nm. PCR amplification and sequencing of the polh gene region using universal primers followed by BLAST analysis revealed a 93% similarity to a partial polh gene sequence from Epinotia granitalis NPV. Further genetic characterisation involving single restriction endonuclease (REN) digestion of genomic DNA was carried out to generate profiles for comparison against other baculovirus species and potential new isolates of the same virus. The complete genome of the virus was sequenced, assembled and analysed for a more comprehensive genetic analysis. The genome was 115 728 base pairs (bp) in length with a GC content of 37.2%. A total of 126 open reading frames (ORFs) were identified with minimal overlap and no preference in orientation. Bioassays were used to determine the virulence of the NPV against C. peltastica. The NPV was virulent against C. peltastica with an LC50 value of 6.46 × 103 OBs/ml and an LC90 value of 2.46 × 105 OBs/ml, and time mortality ranging between 76.32 h and 93.49 h. This is the first study to describe the isolation and genetic characterisation of a novel SNPV from C. peltastica, which has potential for development into a biopesticide for the control of this pest in South Africa.
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Navigating Multiple Tensions for Engaged Praxis in a Complex Social-Ecological System
- Authors: Cockburn, Jessica J , Palmer, Carolyn G , Biggs, Harry , Rosenberg, Eureta
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/127886 , vital:36052 , https://doi.org/10.3390/land7040129
- Description: Recently, the 33-year journey of the Southern African Journal of Environmental Education (SAJEE) was the subject of reflection during an Open Access Publishing week convened by Rhodes University Library Services. Two former and current editors-in-chief shared the SAJEE’s story of publishing ‘from the margins into the centre’. In the early 1990s, the Journal was mailed to the Environmental Education Association of Southern Africa (EEASA) membership from the foyer of the Rhodes Education Department (which had the floor space for stuffing and stacking A4 envelopes). In the first decade of this century, the Journal arrived at a symbolic ‘centre’ with digital distribution, first on the EEASA website and then from the Open Access platform provided by African Journals Online (AJOL). The digital move was vital for sustained and increased distribution in a time of shrinking budgets and growing costs. The results, shared with the EEASA Council earlier this year, were nothing short of spectacular: In March 2017, the SAJEE received more than 1 250 article downloads (www.ajol.info/index.php/sajee), and the number of downloads have stayed above 500 each month subsequently (Figure 1). Views and downloads are recorded around the world including,
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New thiazolidine-2,4-dione derivatives combined with organometallic ferrocene: Synthesis, structure and antiparasitic activity
- Authors: Oderinlo, Ogunyemi O , Tukulula, Matshawandile , Isaacs, Michelle , Taylor, Dale , Smith, Vincent J , Khanye, Setshaba D , Hoppe, Heinrich C
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/122978 , vital:35382 , https://doi.org/10.1002/aoc.4385
- Description: Favourable physicochemical properties of an organometallic ferrocene and antiplasmodial potency of compounds containing the thiazolidine‐2,4‐dione framework (TZD‐4) prompted us to explore compounds containing both the thiazolidine‐2,4‐dione core and the ferrocenyl unit with the primary aim of identifying compounds with promising antiprotozoal activities. Thus, a new series of rationally designed ferrocene‐based thiazolidine‐2,4‐dione derivatives, containing a selection of secondary cyclic amines, was synthesised and fully characterised using standard spectroscopic techniques. The resulting compounds were screened for their antiplasmodial and antitrypanosomal activities against both the chloroquine‐resistant (Dd2) strain of Plasmodium falciparum and the Nagana Trypanosoma brucei brucei 427. The general trend that emerged indicated that the target compounds were more selective towards T. b. brucei compared to the P. falciparum parasite. Moreover, the analogues bearing methylpiperazine (8a) and piperidine (8b) rings were more active against T. b. brucei compared to hit compound TZD‐4. Except compound 8b, which appeared promising, none of the synthesised compounds showed better activity than TZD‐4 against the P. falciparum parasite. All the synthesised compounds were non‐toxic and often showed >90% viability of the HeLa cell line screened.
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Niq Mhlongo told us# FeesMustFall, or why the surface matters in Dog Eat Dog:
- Authors: Dass, Minesh
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/142609 , vital:38095 , DOI: 10.4314/eia.v45i3.6
- Description: In this paper, I investigate some of the reasons for the relative paucity of scholarly attention given to Niq Mhlongo’s debut novel, Dog Eat Dog. I argue that this text anticipates and articulates themes that are vital to contemporary South African culture generally, and to the academic space of the university specifically. For this reason, I contend that it is a work worthy of consideration, both because of its unusual form (it is a novel of ordeal rather than a Bildungsroman), and its prescient depiction of issues to do with institutional racism and academic exclusion – subjects which were central during the student-led protests on South African campuses in 2015 and 2016. A principal thesis of this article is that one of the reasons for literary study’s unwillingness to engage with the novel is the discipline’s predisposition to a hermeneutics of suspicion, a method of analysis that I show is unsuited to Mhlongo’s text. Instead, I argue for the use of surface reading as a valid and appropriate praxis given the form and the content of Dog Eat Dog.
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NMR structural elucidation of channaine, an unusual alkaloid from Sceletium tortuosum:
- Authors: Veale, Clinton G L , Chen, Weiyang , Chaudhary, Sushil , Kituyi, Sarah N , Isaacs, Michelle , Hoppe, Heinrich C , Edkins, Adrienne L , Combrinck, Sandra , Mehari, Bewketu , Viljoen, Alvaro
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/164345 , vital:41110 , DOI: 10.1016/j.phytol.2017.11.018
- Description: Chemical interrogation of the Sceletium genus and Amaryllidaceae family of plants has yielded a diverse array of aryl-hydroindole containing alkaloids. Included in this class is channaine, which was tentatively identified, without comprehensive structural elucidation from Sceletium tortuosum in 1957. Following its isolation from S. strictum, the structure of channaine was eventually resolved by X-ray crystallographic analysis, which revealed an unusual cage-like ring structure at the interface of two aryl-hydroindole subunits. However, since this report in 1978, channaine has not re-appeared in the literature. In this letter, the full NMR characterisation of channaine, isolated from S. tortuosum collected from St Helena in the Western Cape Province of South Africa, is reported for the first time.
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No evidence for association between APOL1 kidney disease risk alleles and Human African Trypanosomiasis in two Ugandan populations:
- Authors: Kimuda, Magambo P , Noyes, Harry , Mulindwa, Julius , Enyaru, John , Alibu, Vincent P , Sidibe, Issa , Mumba Ngoyi, Dieuodonne , Hertz-Fowler, Christiane , MacLeod, Annette , Tastan Bishop, Özlem , Matovu, Enock
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/162924 , vital:40997 , https://doi.org/10.1371/journal.pntd.0006300
- Description: Human African trypanosomiasis (HAT) manifests as an acute form caused by Trypanosoma brucei rhodesiense (Tbr) and a chronic form caused by Trypanosoma brucei gambiense (Tbg). Previous studies have suggested a host genetic role in infection outcomes, particularly for APOL1. We have undertaken candidate gene association studies (CGAS) in a Ugandan Tbr and a Tbg HAT endemic area, to determine whether polymorphisms in IL10, IL8, IL4, HLAG, TNFA, TNX4LB, IL6, IFNG, MIF, APOL1, HLAA, IL1B, IL4R, IL12B, IL12R, HP, HPR, and CFH have a role in HAT.
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Nontimber forest products as ecological and biocultural keystone species
- Authors: Shackleton, Charlie M , Ticktin, Tamara , Cunningham, Anthony B
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/180388 , vital:43359 , xlink:href="https://doi.org/10.5751/ES-10469-230422"
- Description: Nontimber forests products (NTFPs) are the mainstay of rural livelihoods and local economies the world over. As such they are of interest to a wide disciplinary range of researchers and development and government agencies seeking to promote livelihoods, incomes, and ecologically sustainable practices. With the attention on the various human uses of NTFPs, their role and networks in the broader biological communities in which they are located are frequently overlooked. Harvesting of many NTFPs has effects not only at the organism and population scales, but also on co-occurring species, some of which may also be NTFPs. Thus, reduction or loss of one NTFP population or species in a specific area may have cascade effects on other NTFP species, including those used for cultural purposes. We illustrate the little appreciated importance of NTFPs in broader ecological and social systems by assessing and illustrating the importance of NTFP species as ecological or biocultural keystones in providing regulating and supporting ecological services to other species and cultural services to people. We present a number of examples where NTFP species act as keystones in ecological and cultural systems, including food, pollination and dispersal, animal health, nutrients, shelter and protection, and cultural symbolism, most of which have not been considered by NTFP researchers and practitioners. From these examples we distill six propositions regarding NTFPs and discuss the value of recognizing some NTFPs as biocultural keystones to acknowledge and highlight their roles at broader scales.
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Novel nano-dyad of homoleptic sandwich-type phthalocyanines with nitrogen doped graphene quantum dots for nonlinear optics
- Authors: Oluwole, David O , Nwaji, Njemuwa , Nene, Lindokuhle C , Mokone, Lesedi , Dube, Edith , Nyokong, Tebello
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/233386 , vital:50086 , xlink:href="https://doi.org/10.1039/C8NJ01707G"
- Description: The syntheses of neodymium(III) 2,9,16,23-tetrakis-(2,6-di-tert-butyl-4-methylphenoxy)phthalocyanine (2), bis europium(III) 2,9,16,23-tetrakis-(2,6-di-tert-butyl-4-methylphenoxy)phthalocyanine (3), bis dysprosium(III) 2,9,16,23-tetrakis-(2,6-di-tert-butyl-4-methylphenoxy)phthalocyanine (4) and their conjugated analogues with nitrogen doped quantum dots (NGQDs) are reported herein. The optical nonlinearity of the sandwich-type phthalocyanine complexes and their conjugates with NGQDs were studied in dimethyl sulfoxide using the open aperture Z-scan technique at an excitation wavelength of 532 nm with a 10 ns pulse. The nonlinear absorption coefficient (βeff) value of the samples ranges from 15 cm GW−1 to 89.6 cm GW−1. Complex 4 and its conjugates afforded a strong optical limiting behaviour compared to the other samples. These fabricated complexes and their conjugates with NGQDs could serve as a plausible nonlinear optical (NLO) material due to their fascinating NLO properties.
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