Studies on the fisheries and biology of Oreochromis urolepsis (Pisces: Cichilidae) in the Mtera resorvoir (Tanzania)

The fisheries and some aspects of the biology of Oreochromis urolepsis of the Mtera Reservoir (Tanzania) were examined in August 2002. It was observed that there was no proper management of the reservoir\'s fisheries. Beach seine fishing dominated the fishery. Nearly all the O. urolepsis caught by this type of gear were juveniles. The number of fish caught by the beach seines was very high, some times up to 4,000 fish per haul. The beach seines also destroy the spawning sites for the tilapias. Mean total lengths of O. urolepsis caught in gillnets of legal mesh sizes (ranging from 88 mm and 114 mm), ranged between 22.0 cm and 27 cm. Their mean weights were between 236 g and 433 g. Most of the fish caught were sexually immature. Ninety three per cent of the fish from the 88 mm gillnets were immature, while only 28% of those caught in the 114 mm mesh nets were mature. The smallest mature female had a total length of 24.0 cm. O. urolepsis is a very fecund tilapiine species. A female weighing 450 g was found to contain about 3250 eggs. It was also found that the species is a phytoplankton feeder, taking in diatoms, green and blue green algae. Tanzania Journal of Science Vol. 30 (2) 2004: pp. 33-4

Transmissable Cancer in Tasmanian Devil (Sacrophilus harrisii) and Canine Animal Populations Explained through Immune System Downregulation in Immunocompetent Hosts

Transmissible cancer has been shown to occur in the Tasmanian Devil as well as canine animal populations, known as Devil Facial Tumor Disease (DFTD) and Canine Transmissible Venereal Tumor (CTVT), respectively. Both malignancies show remarkable ability to be transmitted as allografts into hosts. How DFTD, as well as CTVT, avoid detection by immunocompetent hosts is of particular interest as these malignancies are rarely seen in nature. Both transmissible cancers show the ability to downregulate the host immune system enabling proliferation. DFTD is characterized by epigenetic modifications of ?2m , TAP1, TAP2, and MHC DNA promoter regions; crucial proteins required in detection and surveillance of foreign material. Downregulation in DFTD may be achieved by altering the activity of histone deacetylases. DFTD has caused widespread destruction of devil populations placing the species on the brink of extinction. CTVT consists of a proliferative phase during which the tumor evades immune detection, allowing it to proliferate; as well as a regressive phase where hosts show the ability to mount an effective immune response. Alteration of TGF-? signaling in CTVT likely impedes the antigen processing capabilities of canine hosts in addition to hindering the ability of natural killer cells to detect immune system downregulation. Immunosuppressive cytokines such as CXCL7 may contribute to a favorable microenvironment enabling the proliferation of CTVT. When viewed from an evolutionary paradigm both DFTD as well as CTVT may conform to a model of host-parasite co-evolution first put forth by J.B.S. Haldane. Furthermore, certain genetic characteristics such as genetically active transposons in CTVT and chromosome rearrangements in DFTD have been shown to play important roles in promoting survival of both transmissible cancers. Understanding the mode of transmission for these transmissible cancers may shed light on mechanisms for human malignancies, in addition to serving as a paradigm for treatment in the future

Limnological studies of the pelagic zone of Lake Tanganyika at Kigoma, Tanzania.

Some limnological parameters and chlorophyll a were determined for twelve months at a pelagic station near Kigoma. Temperatures ranged between 25.7 ºC and 27.3 ºC at the surface, and 24.1 oC and 24.7 oC at100 m. Thermal stratification persisted throughout the year with the thermocline oscillating between 15 m in October and 60 m in May. Dissolved oxygen concentrations were high at the surface, ranging between 6.59 mg l-1 and 8.15 mg l-1, while at 100 m the concentrations ranged from less than 0.20 mg l-1 to 1.94 mg l-1. Nitrate-nitrogen concentrations in surface water ranged between 26 µg N l-1 in May and 74 µg N l-1in December. Nitrate -nitrogen concentrations generally increased with depth to 80 m, after which they decreased. Soluble reactive phosphorus concentrations in the photosynthetic zone were always very low, ranging between 0.30 µg P l-1 and 4.0 µg P l-1. The concentrations increased with depth. Total phosphorus concentrations in the surface water were also low, ranging between 2.0 µg P l-1 in March and 12.0 µg P l-1 in August. The concentrations increased with depth. Chlorophyll a concentrations were generally low throughout the year, except for October and April-May when high concentrations were found. In October the mean concentration was 4.52 µg Chl a l-1, while January had the lowest concentrations with a mean of 0.36 µg Chl a l-1. Chlorophyll a concentrations decreased with depth. Tanzania Journal of Science Vol. 32 (2) 2006: pp. 23-3

Generative Methods, Meta-learning, and Meta-heuristics for Robust Cyber Defense

Cyberspace is the digital communications network that supports the internet of battlefield things (IoBT), the model by which defense-centric sensors, computers, actuators and humans are digitally connected. A secure IoBT infrastructure facilitates real time implementation of the observe, orient, decide, act (OODA) loop across distributed subsystems. Successful hacking efforts by cyber criminals and strategic adversaries suggest that cyber systems such as the IoBT are not secure. Three lines of effort demonstrate a path towards a more robust IoBT. First, a baseline data set of enterprise cyber network traffic was collected and modelled with generative methods allowing the generation of realistic, synthetic cyber data. Next, adversarial examples of cyber packets were algorithmically crafted to fool network intrusion detection systems while maintaining packet functionality. Finally, a framework is presented that uses meta-learning to combine the predictive power of various weak models. This resulted in a meta-model that outperforms all baseline classifiers with respect to overall accuracy of packets, and adversarial example detection rate. The National Defense Strategy underscores cybersecurity as an imperative to defend the homeland and maintain a military advantage in the information age. This research provides both academic perspective and applied techniques to to further the cybersecurity posture of the Department of Defense into the information age

Comparative Analysis of Non-Infrastructural Impacts of Floods Case Study: 2011 And 2014 Floods in Dar Es Salaam

This study compared and analysed the non -infrastructural impacts of 2011 and 2014 floods disaster in Dar es Salaam. This study area particularly involved the 15 wards in Dar es Salaam. Both qualitative and quantitative data were collected using different data collection methods.  The variety of data collection methods were used in this study in which qualitative data were collected through physical investigation/observation including visual inspections of damaged. Questionnaire was conducted to the affected households. Interview was conducted to the ward executive officers (WEOs) and district disaster focal point officer.  Consultation was conducted to the disaster management stakeholder. The findings of this study based on non-infrastructural impacts that occurred in 2011 and 2014 floods include death, damage to property mostly houses. Social impacts include disruption of social service such as school, water system and hospital. Environmental impacts include water and air pollution, destruction of ecosystem. Economic impacts such as the cost for rebuilding, medical treatment, food and shelter. Health impacts include eruption of diseases such as malaria, respiratory disease, and cholera.  The non-infrastructural impacts that are related to floods include death, property damage, economic, social, health, environment and safety and security.  The 2014 flood was more severe as it caused great impacts on infrastructures, economy, social services and environment. Due to lack of awareness, training and preparedness, the 2011 floods also caused great impacts in life and properties. Also, the response authorities did not respond accordingly. The study recommends that areas prone to flood should be mapped and the awareness of people on disaster risks should be created so as to reduce the occurrence of the impacts. Keywords: Non-infrastructural impacts; Flooding and Floods risks; Disaster; Coping strategies

Trends of Avicennia marina Productivity as Influenced by Climatic Seasons: A Case Study of Mbweni Mangrove Forest Ecosystem

Avicennia marina (Forsk.) Vierh. is a salt tolerant plant that grows in the saline environment along the coastline. A study was carried out at Mbweni Mangrove Forests aimed at evaluating the effects of different climatic seasons on the productivity, growth, survival and spread of A. marina. A. marina litter falls were collected in nine litter traps set randomly at different stands of the mangrove forest where A. marina occupied at a density of 0.10 individual/m2. Monthly collected litter were sorted into separate components, i.e. leaves, stems and seeds, weighed, recorded and mean weight values were calculated. From the litter, Sodium ions were determined by using Atomic Absorption Spectrophotometer method while Chlorine ions were determined by Ion Chromatography method. In leaf litter accumulation, the highest production was found in September with a mean weight of 78.53g/m2. For Sodium and Chlorine ions, the mean concentration started to rise during the dry season of June to September. Lowest leaf litter mean values were recorded in April with a mean weight of 7.23g/m2 and the concentration of Sodium and Chlorine ions was found lower during the wet season of April and May. For the propagule organs, data were recorded for only three months in which the highest accumulation was found in April with a mean value of 19.3g/m2. During wet season in the month of April, high rates of propagules accumulation with dispersal was accelerated by water runoff leading to establishment of new colonies. For the duration of dry season (June to August) the soils had extreme salinity due to low rainfall. The inorganic ions, sodium (Na) and Chlorine (Cl) started to accumulate in the plant in order to maintain the homeostatic control, turgor pressure and osmotic adjustment. Accumulation of these ions and salts resulted to high productivity of leaf litter in September as a means of removing excess ions and unwanted salts. This was facilitated by strong wind that finally brought short rains in the month of November that also resulted to new vegetation. From this study, it can be concluded that varying climatic seasons has effects to A. marina productivity, growth and survival in the salt stressed environment, indicating that mangroves have a salt tolerant characteristics.Key words: Avicennia marina, propagule organs, productivity, leaf litter, salinity

A formação de oficiais nas Forças Armadas de Moçambique

O trabalho tem por objectivo elaborar um modelo de formação para os oficiais das Forças Armadas de Moçambique, coerente, exequível, racional e rendível, a partir da caracterização do actual modelo. A visão é melhorar cada vez mais a formação conjunta para os três Ramos através de um tronco comum, e uma prática dispersa nos Ramos através das Escolas Práticas comuns nos Ramos, ou seja: a formação inicial de nível de licenciatura/mestrado é feita na Academia Militar, seguido de cursos de promoção a Capitão na Escola Prática do Ramo para as Armas e na Escola Prática de Serviços comum a todos os Ramos, e finalmente os cursos de promoção a oficial superior, estado-maior (específico e conjunto/combinado), Comando e Direcção de tropas e o de oficial general no futuro Instituto de Estudos Superiores Militares de Moçambique. Para o efeito, será feito um levantamento das necessidades de oficiais a partir da actual estrutura orgânica de modo a recomendar ao Departamento de Doutrina e Formação Militar, à Academia Militar, à Escola Prática de Serviços, às Escolas Práticas dos Ramos a Instituto de Estudos Superiores Militares um plano de formação, para responder ao preenchimento da estrutura orgânica num horizonte temporal de 5, 10 e 20 anos, a partir das necessidades reais de cada Ramo. Posteriormente, será efectuado um estudo da situação demográfica, dos recursos materiais, equipamentos, infra-estruturas, orçamento e definição de políticas com vista a sensibilizar quem de direito, questionar, analisar no sentido de sobre o processo de formação acelerado de oficiais, para num prazo de 20 anos possamos substituir todos os níveis de Comando e Direcção de tropas, detidos actualmente por oficiais sem formação adequada para o lugar/posto. Para procurar dar resposta à questão central, o estudo foi estruturado em seis capítulos: Introdução, caracterização do actual modelo de formação, desafios e vulnerabilidades, impacto da formação, modelo adequado, e conclusões e recomendações. Finalmente, e com base no Protocolo de Bolonha, o estudo abordará a introdução na Academia Militar de Nampula de competências para conferir o grau de Mestrado, Pós-graduação e Doutoramento no futuro Instituto de Estudos Superiores Militares. Abstract: The following study has, as main point the construction of a new Mozambique Officer´s education model- coherent, practicable, rational and profitable - based on the present model. The aim is to improve the three services of the armed forces joint education system through a centralized body generated through the Practical Schools that are common to all the services. This means an initial education taking place in the Military Academy at graduate/master degree, followed by Captain’s Promotion Courses at Branches and Services Practical Schools common to all the Services and, finally, the Senior Officer´s Promotion Course, Staff Officer´s Course (joint and specific to each Service), Troops Leadership and Promotion to General Officer Courses in the future at the Mozambique Staff College (Instituto de Estudos Superiores Militares). For this purpose, taking into account the present military structure, the number of Officers needed will be raised, in order to recommend the Military Formation and Doctrine Department, the Military Academy, the Services Practical School, the Army Branches Practical Schools and the Staff College with an education plan in order to fulfill the military structure within a 5, 10 and 20 years’ timeframe, having into consideration what the Services need. After that, it will take place a study about the demographic situation, the material and equipment resources, infrastructures, budget and definition of the policies in order to provide awareness to who is in charge, questioning and analyze in order to provide a solution for, in a 20 years’ timeframe, through an accelerated Officers education plan, being able to replace all the Commander´s levels, presently occupied by Officers without the proper education level. In order to search for an answer to the main question, the study was organized on six chapters: an introduction, a characterization of the present formation model, the challenges and vulnerabilities, the formation impact on the Officers carrier development and progression, an Officers education model to be implemented, and conclusions and recommendations. Finally, taking into account the Bologna Protocol, the study will address the introduction of competencies in the Nampula Military Academy to confer a masters degree and in the future Staff College (Instituto de Estudos Superiores Militares) a PhD

El desafío de la enseñanza de robótica en las instituciones educativas

This article pretends to develop the innovation in teaching strategies focused in learning based on problems and development of computational thought. From the educational point of view, programming enables not only the activation of a wide variety of learning styles, it commits students to consider various problem-solving aspects: deciding about the problem nature, selecting a representation that helps solving it and monitoring their own thoughts and solving-strategies. To understand and problematize knowledge related to technological context it is not enough to know, name or be in frequent contact with technological devices. Technology functioning logic is not revealed in its mere use. Solving problems with computational thought resources may become in an excellent tool to acquire the habit of facing problems in a rigorous and systematic way, even when a computer (or similar device) is not used to solve them. The inclusion of robotics teaching in all the provinces in our country starts within the Federal Bureau of Education, where a plan of digital education is proposed and agreed. In that way, programming and robotic, are two areas that are already being worked on framed on a digital literacy process.The relationship and practice of the LBP methodological strategy and the development of computational thought are raised. Even though the federal implementation framework is approached through programs such as Learning Connected, it is considered that educational robotics is not exclusively about teachers teaching robotics, but about the technological resource being used to generate competencies such as autonomy, initiative, responsibility, creativity, teamwork, self-esteem and interest towards research.El presente artículo pretende desarrollar la innovación en las estrategias de enseñanza focalizando en el Aprendizaje basado en Problema y el desarrollo del pensamiento computacional. Desde el punto de vista educativo, la programación posibilita no solo activar una amplia variedad de estilos de aprendizaje, compromete a los estudiantes en la consideración de varios aspectos para la solución de problemas: decidir sobre la naturaleza del problema, seleccionar una representación que ayude a resolverlo y monitorear sus pensamientos y estrategias de solución enmarcada en la educación digital. Para comprender y problematizar los saberes vinculados al contexto tecnológico no alcanza con conocer o estar en constante contacto con dispositivos tecnológicos. Solucionar problemas con los recursos del pensamiento computacional puede convertirse en una excelente herramienta para enfrentar problemas de manera rigurosa y sistemática, aun, cuando no se utilice una computadora (o recurso tecnológico similar) para solucionarlo. Es importante destacar que tanto el significado de la robótica como el abordaje de su integración en el ámbito educativo tienen un sentido histórico ya que la robótica educativa se propuso como recurso para el aprendizaje de las ciencias, incluyendo aspectos relacionados con la mecánica, en una sociedad en la cual los robots tenían una presencia significativa en la ciencia ficción y escasa en el mundo real. En los últimos años, la robótica emergió asociada a circuitos digitales y, en muchos casos, a la inteligencia artificial, mientras que ganó protagonismo y relevancia en distintos ámbitos del desarrollo social y económico. Por esta razón, y en relación con su trascendencia en la cultura digital, se propone a la robótica como objeto de estudio en sí misma, particularmente en sus aspectos ligados a los sistemas digitales de control y automatización, estrechamente vinculados a la programación. Un aspecto fundamental de la comunicación con robots es el lenguaje no verbal, que se está perfeccionando para mejorar la interacción con las personas. El desafío de la enseñanza de robótica en las instituciones educativas 30 Los nuevos dispositivos consideran la interacción que promueve un intercambio en el cual los dispositivos interactúan estableciendo una comunicación. Actualmente se estudian los modos comunicacionales que se establecen en las aulas a partir del lenguaje y el pensamiento computacional que se logra utilizando la programación. Se plantea la relación y puesta en práctica de la estrategia metodológica del ABP y el desarrollo del pensamiento computacional.O presente artígo pretende desenvolver a inovação em estratégicas de ensinamento focalizando na Aprendizagem em base no Problema e em desenvolvimento de pensamento computacional. Desde um ponto de vista educativo, a programação possibilita não somente ativar uma amplia variedade de estilos de aprendizagem, compromete aos estudantes em considerar vários aspectos para a solução dos problemas: dizer sobre a natureza do problema, seleccionar uma representação que ajuda a resolverlo e monitorar seus próprios pensamentos e estratégias de solução.Para comprender e problematizar os saberes vinculados ao contexto tecnológico não alcança conhecer , nomear ou estar em constante contato com dispositivos tecnológicos. As lógicas de funcionamento de tecnologia não se revelam com seu mero uso. Solucionar problemas com os recursos de pensamento computacional pode converterse em uma excelente ferramenta para adquirir o costume de enfrentar problemas de maneira rigorosa e sistemática, ainda mais cuando não se utiliza um computador (ou recurso tecnológico similar) para soluciona-lo. A incorporação de ensinamento da Robótica em todas as províncias do nosso país surge núcleo do Conselho Federal de Educação, onde se propõem e acorda avançar em um plano de educação digital. De ese modo, a programação e a robótica, duas áreas em que já se trabalha enquadrada em um processo de alfabetização digital. Se expõem a relação e põem em prática na estratégia metodológica da ABP e o desenvolvimento do pensamento computacional. Se bem abordamos o marco federal da implementação através dos programas como Aprender Conectados, consideramos que a robótica educativa não se trata exclusivamente de que o docente ensine robótica, se não de que utiliza este recurso tecnológico para generar competências como: a autonomía, a iniciativa, a responsabilidade, a criatividade, o trabalho em equipe, a autoestima e o interesse pela investigação

LAS PRÁCTICAS DE GESTIÓN DIRECTIVA EN LA EDUCACIÓN RURAL SECUNDARIA EN LA NUEVA NORMALIDAD.

This article describes the emergence of a new organizational model of rural schools in the Province of Santa Fe, Secondary  Rural Nuclei that are configured based on territorial groupings in the framework of the compulsory Secondary Level sanctioned by Law 26.206. In this new organization, tensions arise between the exercise of traditional management practices, the new reconfigurations and the health emergency. The importance of management is recognized, where the actions that drive  institutional improvement in the context of pandemic and post-pandemic are nested. A reflective contribution is made to redefine management practices that guide the improvement of secondary schools in rural contexts, in view of the challenges of the new normal.El presente artículo describe el surgimiento de un nuevo modelo organizativo de escuela rural en la provincia de Santa Fe,  núcleos rurales secundarios que se configuran sobre la base de los agrupamientos territoriales en el marco de la obligatoriedad del Nivel Secundario sancionada por la Ley 26.206. En esta nueva organización se producen tensiones entre el ejercicio de las prácticas de gestión tradicionales, las nuevas reconfiguraciones y la emergencia sanitaria. Se reconoce la importancia de la gestión donde anidan las acciones que motorizan la mejora institucional en contexto de pandemia y pospandemia. Se realiza un aporte reflexivo que resignifica las prácticas de gestión que orientan la mejora de la escuela  secundaria en contexto rural, con atención a los desafíos de la nueva normalidad.Este artigo descreve a emergência de um novo modelo organizacional de escolas rurais na Província de Santa Fé, Centros Secundários Rurais que se configuram a partir de grupos territoriais no âmbito do Nível Secundário Compulsório sancionado pela Lei 26.206. Nessa nova organização, surgem tensões entre o exercício das práticas tradicionais de gestão, as novas reconfigurações e a emergência sanitária. É reconhecida a importância da gestão, a partir da qual são tomadas ações que promovam a melhoria institucional no contexto da pandemia e pós-pandemia. Uma contribuição ponderada foi feita pararedefinir as práticas de gestão que orientam a melhoria das escolas secundárias em contextos rurais, diante dos desafios da nova normalidade. &nbsp