Effect of turbidity on the foraging success of Glossogobius callidus (Teleostei: Gobiidae)
- Parkinson, Matthew C, Booth, Anthony J
- Authors: Parkinson, Matthew C , Booth, Anthony J
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124375 , vital:35600 , https://doi.org/10.2989/16085914.2011.589120
- Description: Particles suspended in water attenuate the light that passes through it via absorption or scattering (Utne-Palm 2002). For example, whereas algae absorb specific wavelengths of light necessary for photosynthesis, inorganic suspensoids tend to scatter light (Radke and Gaupisch 2005). This results in lowered ambient light levels and reduces the visual acuity of aquatic organisms. From a fish’s perspective, an increase in water turbidity has the potential to alter visually-mediated reproductive behaviours (Järvenpää and Lindström 2004), predator avoidance (Meager et al. 2006) and foraging success negatively (Utne-Palm 2002, Rowe et al. 2003, Sweka and Hartman 2003, Stuart-Smith et al. 2004). The foraging success of various fish species was affected by increased turbidity through decreasing predator–prey encounter rates (Sweka and Hartman 2003) and through decreasing visual acuity whereby the distance at which prey are visually detected is reduced (Utne-Palm 2002).
- Full Text:
- Date Issued: 2011
- Authors: Parkinson, Matthew C , Booth, Anthony J
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124375 , vital:35600 , https://doi.org/10.2989/16085914.2011.589120
- Description: Particles suspended in water attenuate the light that passes through it via absorption or scattering (Utne-Palm 2002). For example, whereas algae absorb specific wavelengths of light necessary for photosynthesis, inorganic suspensoids tend to scatter light (Radke and Gaupisch 2005). This results in lowered ambient light levels and reduces the visual acuity of aquatic organisms. From a fish’s perspective, an increase in water turbidity has the potential to alter visually-mediated reproductive behaviours (Järvenpää and Lindström 2004), predator avoidance (Meager et al. 2006) and foraging success negatively (Utne-Palm 2002, Rowe et al. 2003, Sweka and Hartman 2003, Stuart-Smith et al. 2004). The foraging success of various fish species was affected by increased turbidity through decreasing predator–prey encounter rates (Sweka and Hartman 2003) and through decreasing visual acuity whereby the distance at which prey are visually detected is reduced (Utne-Palm 2002).
- Full Text:
- Date Issued: 2011
Bandwidth management and monitoring for community networks
- Irwin, Barry V W, Siebörger, Ingrid, Wells, Daniel
- Authors: Irwin, Barry V W , Siebörger, Ingrid , Wells, Daniel
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428040 , vital:72482 , https://www.researchgate.net/profile/Ingrid-Sieboerger/publication/265121154_Bandwidth_management_and_monitoring_for_community_networks/links/5e538b85458515072db7a686/Bandwidth-management-and-monitoring-for-community-networks.pdf
- Description: This paper describes a custom-built system to replace existing routing solutions within an identified community network. The community net-work in question shares a VSAT Internet connection to provide Internet access to a number of schools and their surrounding communities. This connection provides a limited resource which needs to be managed in order to ensure equitable use by members of the community. The community network originally lacked any form of bandwidth manage-ment or monitoring which often resulted in unfair use and abuse. The solution implemented is based on a client-server architecture. The Community Access Points (CAPs) are the client components which are located at each school; providing the computers and servers with ac-cess to the rest of the community network and the Internet. These nodes also perform a number of monitoring tasks for the computers at the schools. The server component is the Access Concentrator (AC) and connects the CAPs together using encrypted and authenticated PPPoE tunnels. The AC performs several additional monitoring func-tions, both on the individual links and on the upstream Internet connec-tion. The AC provides a means of effectively and centrally managing and allocating Internet bandwidth between the schools. The system that was developed has a number of features, including Quality of Service adjustments limiting network usage and fairly billing each school for their Internet use. The system provides an effective means for sharing bandwidth between users in a community network.
- Full Text:
- Date Issued: 2010
- Authors: Irwin, Barry V W , Siebörger, Ingrid , Wells, Daniel
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/428040 , vital:72482 , https://www.researchgate.net/profile/Ingrid-Sieboerger/publication/265121154_Bandwidth_management_and_monitoring_for_community_networks/links/5e538b85458515072db7a686/Bandwidth-management-and-monitoring-for-community-networks.pdf
- Description: This paper describes a custom-built system to replace existing routing solutions within an identified community network. The community net-work in question shares a VSAT Internet connection to provide Internet access to a number of schools and their surrounding communities. This connection provides a limited resource which needs to be managed in order to ensure equitable use by members of the community. The community network originally lacked any form of bandwidth manage-ment or monitoring which often resulted in unfair use and abuse. The solution implemented is based on a client-server architecture. The Community Access Points (CAPs) are the client components which are located at each school; providing the computers and servers with ac-cess to the rest of the community network and the Internet. These nodes also perform a number of monitoring tasks for the computers at the schools. The server component is the Access Concentrator (AC) and connects the CAPs together using encrypted and authenticated PPPoE tunnels. The AC performs several additional monitoring func-tions, both on the individual links and on the upstream Internet connec-tion. The AC provides a means of effectively and centrally managing and allocating Internet bandwidth between the schools. The system that was developed has a number of features, including Quality of Service adjustments limiting network usage and fairly billing each school for their Internet use. The system provides an effective means for sharing bandwidth between users in a community network.
- Full Text:
- Date Issued: 2010
Data classification for artificial intelligence construct training to aid in network incident identification using network telescope data
- Cowie, Bradley, Irwin, Barry V W
- Authors: Cowie, Bradley , Irwin, Barry V W
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430125 , vital:72667 , https://doi.org/10.1145/1899503.1899544
- Description: This paper considers the complexities involved in obtaining training da-ta for use by artificial intelligence constructs to identify potential network incidents using passive network telescope data. While a large amount of data obtained from network telescopes exists, this data is not current-ly marked for known incidents. Problems related to this marking process include the accuracy of the markings, the validity of the original data and the time involved. In an attempt to solve these issues two methods of training data generation are considered namely; manual identification and automated generation. The manual technique considers heuristics for finding network incidents while the automated technique considers building simulated data sets using existing models of virus propagation and malicious activity. An example artificial intelligence system is then constructed using these marked datasets.
- Full Text:
- Date Issued: 2010
- Authors: Cowie, Bradley , Irwin, Barry V W
- Date: 2010
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/430125 , vital:72667 , https://doi.org/10.1145/1899503.1899544
- Description: This paper considers the complexities involved in obtaining training da-ta for use by artificial intelligence constructs to identify potential network incidents using passive network telescope data. While a large amount of data obtained from network telescopes exists, this data is not current-ly marked for known incidents. Problems related to this marking process include the accuracy of the markings, the validity of the original data and the time involved. In an attempt to solve these issues two methods of training data generation are considered namely; manual identification and automated generation. The manual technique considers heuristics for finding network incidents while the automated technique considers building simulated data sets using existing models of virus propagation and malicious activity. An example artificial intelligence system is then constructed using these marked datasets.
- Full Text:
- Date Issued: 2010
Hipper redacted:
- Authors: Jamal, Ashraf
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147902 , vital:38683 , DOI: 10.1080/02560046.2010.511888
- Description: The work of contemporary South African artist, mark Hipper, has been dogged by controversy.
- Full Text:
- Date Issued: 2010
- Authors: Jamal, Ashraf
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/147902 , vital:38683 , DOI: 10.1080/02560046.2010.511888
- Description: The work of contemporary South African artist, mark Hipper, has been dogged by controversy.
- Full Text:
- Date Issued: 2010
Promoting entrepreneurship in agriculture in the Eastern Cape:
- Antrobus, Geoffrey G, Fraser, Gavin C G
- Authors: Antrobus, Geoffrey G , Fraser, Gavin C G
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143067 , vital:38198 , DOI: 10.1080/03031853.1994.9524779
- Description: Selected cases in developing entrepreneurship in small-scale subsistence and commercial agriculture in the Eastern Cape are examined, including the provision of marketing facilities, the training programme of the Africa Cooperative Action Trust (ACAT) in Ciskei, government sponsored irrigation projects and the farmer support programme. An attempt is made to draw general conclusions about the necessary ingredients for successful entrepreneurship and the formulation of proposals for further promoting entrepreneurship in agriculture in South Africa.
- Full Text:
- Date Issued: 2010
- Authors: Antrobus, Geoffrey G , Fraser, Gavin C G
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/143067 , vital:38198 , DOI: 10.1080/03031853.1994.9524779
- Description: Selected cases in developing entrepreneurship in small-scale subsistence and commercial agriculture in the Eastern Cape are examined, including the provision of marketing facilities, the training programme of the Africa Cooperative Action Trust (ACAT) in Ciskei, government sponsored irrigation projects and the farmer support programme. An attempt is made to draw general conclusions about the necessary ingredients for successful entrepreneurship and the formulation of proposals for further promoting entrepreneurship in agriculture in South Africa.
- Full Text:
- Date Issued: 2010
Rhodes University 2010 Graduation Ceremonies Address
- Authors: Badat, Saleem
- Date: 2010
- Language: English
- Type: text
- Identifier: vital:7586 , http://hdl.handle.net/10962/d1006577
- Description: From introduction: Most of you who are graduating were born in the late 1980s, a period of great turbulence and social conflict. This was, however, also a time of great optimism for it was clear that apartheid tyranny could no longer continue and had to give way to a new social order. We must take immense pride in the imagination, creativity, ingenuity and courage that we displayed as a people to rid ourselves of tyranny and to fashion our democracy. You are a generation that has been, thankfully, largely spared the horrors, brutality and injustices of apartheid. You are the first generation with the opportunity of living in a society founded on a democratic Constitution that proclaims the commitment to human dignity, the achievement of equality, and the advancement of non-sexism and non-racialism and the human rights and freedoms that are contained in our Bill of Rights.
- Full Text:
- Date Issued: 2010
- Authors: Badat, Saleem
- Date: 2010
- Language: English
- Type: text
- Identifier: vital:7586 , http://hdl.handle.net/10962/d1006577
- Description: From introduction: Most of you who are graduating were born in the late 1980s, a period of great turbulence and social conflict. This was, however, also a time of great optimism for it was clear that apartheid tyranny could no longer continue and had to give way to a new social order. We must take immense pride in the imagination, creativity, ingenuity and courage that we displayed as a people to rid ourselves of tyranny and to fashion our democracy. You are a generation that has been, thankfully, largely spared the horrors, brutality and injustices of apartheid. You are the first generation with the opportunity of living in a society founded on a democratic Constitution that proclaims the commitment to human dignity, the achievement of equality, and the advancement of non-sexism and non-racialism and the human rights and freedoms that are contained in our Bill of Rights.
- Full Text:
- Date Issued: 2010
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