98 research outputs found

    Morfometrijsko ispitivanje nabora crevne sluzokože šarana hranjenog različitom dodatnom hranom u poluintenzivnom sistemu

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    U poluintenzivnom sistemu gajenja šarana u poslednjoj deceniji dolazi do promena u vrsti dodatne hrane koje povećavaju održivost proizvodnje. Sa žitarica koje su se godinama koristile kao dodata hrana, sada se prelazi na peletiranu i ekstrudiranu hranu. Ova zamena uzrokuje i promene u fiziologiji varenja riba, a kao posledica se dešavaju morfološke promene na crevima. Najčešće se na organima za varenje riba gajenih u akvakulturi ne nalaze teže histopatološke promene, pa se pribegava kvantifikaciji i morfometriji histoloških parametara koje mogu da ukažu na odstupanja od normalne građe/funkcije. Metod evaluacije dužine crevnih nabora je korišćen u velikom broju studija koje su se bavile efektima različitih tipova hrane i/ili aditiva na crevo riba. Cilj rada je da se utvrdi efekat različitih tipova hrane (žitarice, peletirana, ekstrudirana hrana) na crevo šarana merenjem dužine crevnih nabora kod riba koje su gajene poluintenzivno. Dužina crevnih nabora je korelisana sa prirastom ribe. Kretanje dužine crevnih nabora po jezerima/vrsti dodate hrane je imalo pravilan tok (Fig. 1). Najkraći crevni nabori su izmereni kod riba hranjenih žitaricama. U sva tri jezera primetan je pad dužine nabora u junu. U ovom mesecu su vrednosti najmanje, manje čak i od inicijalnih na početku eksperimenta (u aprilu), kao i vrednosti dobijenih u maju. Od juna dužina nabora creva konstantno raste kod riba u svim jezerima, bez obzira na tip dodate hrane. Rezultati su pokazali visok stepen statistički značajne korelacije između mase tela ribe i dužine crevnih nabora u svim jezerima (Tab. 2). Ukoliko se posmatraju pojedinačna jezera, vrednosti se kreću između 0.82 kod riba hranjenih peletiranom hranom, preko 0.83 kod riba hranjenih žitaricama do 0.86 kod riba hranjenih ekstrudiranom hranom. Dužina crevnih nabora je koristan parametar u eksperimentima ishrane riba i često se primenjuje u proceni efekta određene hrane na crevo riba. Smanjenje dužine nabora može da ukaže na pojavu enteritisa, na nedovoljnu ishranu ili gladovanje. Naši rezultati pokazuju pozitivnu korelaciju između mase tela ribe i dužine crevnih nabora. Oni su u skladu i sa sličnim istraživanjima koja su sprovedena na drugim životinjskim vrstama, mahom na domaćim životinjama. Crevni nabori na početku eksperimenta ne rastu, čak pokazuju trend pada sve do juna meseca i to iako ribe pokazuju konstantan prirast u svim jezerima, što se objašnjava količinom prirodne hrane koja je u to doba najveća u jezerima. Naime, na osnovu analize prirodne hrane tokom ovog perioda možemo videti da postoji velika biomasa zooplanktona u toku aprila, maja i juna dok je zoobentos na niskom nivou u svim jezerima u toku celog eksperimenta i ne prelazi 10 g/m2. Ovo uzrokuje promene u načinu ishrane ribe od juna meseca. Do tada se šaran hranio uglavnom zooplanktonom, koga je bilo u izobilju, a nakon toga, početkom juna, zbog nedostatka prirodne hrane,riba počinje da sve više konzumira dodatu, što uzrokuje i povećanje dužine crevnih nabora, s obzirom da su pelete, kojom se ribe hrane voluminoznije i većih dimenzija od zooplanktona. Hranjenjem, ribe pune creva i samim tim ih i šire, što omogućava povećanje apsorpcione površine povećanjem dužine crevnih nabora. Ovaj fenomen u stvari predstavlja adaptaciju creva na različite tipove hrane kod riba. Naše istraživanje je pokazalo da praćenje histologije šarana može da ukaže kako se odvija proces varenja zavisno od dela sezone/razvoja zajednice zooplanktona, ali i vrste dodate hrane u poluintenzivnom sistemu

    Glandular trichomes on the leaves of Rosmarinus officinalis: Morphology, stereology and histochemistry

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    Stereological and histochernical analyses of the glandular trichomes on leaves of Rosmarinus officinalis were carried out using light and fluorescence microscopy. Non-glandular and two types of glandular trichomes - peltate and capitate - are described. The stereological method was used for estimating the volume density of epidermis, mesophyll, mechanical tissue, central cylinder, intercellular spaces and volume density of different types of glandular trichomes. The results showed that the volume density of adaxial epidermis was higher than abaxial epidermis. The volume density of peltate trichomes was higher than the volume density of capitate ones. The values obtained for number of peltate and capitate trichomes showed that the capitate trichomes type I were more numerous. The histochernical tests showed positive reactions to proteins and polysaccharides for both types of trichomes, while the phenolic substances were found only in peltate trichomes

    Impact of Plasmodium falciparum infection on the frequency of moderate to severe anaemia in children below 10 years of age in Gabon

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    BACKGROUND: Improving the understanding of childhood malarial anaemia may help in the design of appropriate management strategies. METHODS: A prospective observational study over a two-year period to assess the burden of anaemia and its relationship to Plasmodium falciparum infection and age was conducted in 8,195 febrile Gabonese children. RESULTS: The proportion of children with anaemia was 83.6% (n = 6830), higher in children between the ages of six and 23 months. Those under three years old were more likely to develop moderate to severe anaemia (68%). The prevalence of malaria was 42.7% and P. falciparum infection was more frequent in children aged 36-47 months (54.5%). The proportion of anaemic children increased with parasite density (p 60%), but was unrelated to P. falciparum parasitaemia. CONCLUSION: Malaria is one of the main risk factors for childhood anaemia which represents a public health problem in Gabon. The risk of severe malarial anaemia increases up the age of three years. Efforts to improve strategies for controlling anaemia and malaria are needed

    Population Status of a Cryptic Top Predator: An Island-Wide Assessment of Tigers in Sumatran Rainforests

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    Large carnivores living in tropical rainforests are under immense pressure from the rapid conversion of their habitat. In response, millions of dollars are spent on conserving these species. However, the cost-effectiveness of such investments is poorly understood and this is largely because the requisite population estimates are difficult to achieve at appropriate spatial scales for these secretive species. Here, we apply a robust detection/non-detection sampling technique to produce the first reliable population metric (occupancy) for a critically endangered large carnivore; the Sumatran tiger (Panthera tigris sumatrae). From 2007–2009, seven landscapes were surveyed through 13,511 km of transects in 394 grid cells (17×17 km). Tiger sign was detected in 206 cells, producing a naive estimate of 0.52. However, after controlling for an unequal detection probability (where p = 0.13±0.017; ±S.E.), the estimated tiger occupancy was 0.72±0.048. Whilst the Sumatra-wide survey results gives cause for optimism, a significant negative correlation between occupancy and recent deforestation was found. For example, the Northern Riau landscape had an average deforestation rate of 9.8%/yr and by far the lowest occupancy (0.33±0.055). Our results highlight the key tiger areas in need of protection and have led to one area (Leuser-Ulu Masen) being upgraded as a ‘global priority’ for wild tiger conservation. However, Sumatra has one of the highest global deforestation rates and the two largest tiger landscapes identified in this study will become highly fragmented if their respective proposed roads networks are approved. Thus, it is vital that the Indonesian government tackles these threats, e.g. through improved land-use planning, if it is to succeed in meeting its ambitious National Tiger Recovery Plan targets of doubling the number of Sumatran tigers by 2022

    Newcastle Disease Virus in Madagascar: Identification of an Original Genotype Possibly Deriving from a Died Out Ancestor of Genotype IV

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    In Madagascar, Newcastle disease (ND) has become enzootic after the first documented epizootics in 1946, with recurrent annual outbreaks causing mortality up to 40%. Four ND viruses recently isolated in Madagascar were genotypically and pathotypically characterised. By phylogenetic inference based on the F and HN genes, and also full-genome sequence analyses, the NDV Malagasy isolates form a cluster distant enough to constitute a new genotype hereby proposed as genotype XI. This new genotype is presumably deriving from an ancestor close to genotype IV introduced in the island probably more than 50 years ago. Our data show also that all the previously described neutralising epitopes are conserved between Malagasy and vaccine strains. However, the potential implication in vaccination failures of specific amino acid substitutions predominantly found on surface-exposed epitopes of F and HN proteins is discussed

    Genetic Characterization of Human T-Cell Lymphotropic Virus Type 1 in Mozambique: Transcontinental Lineages Drive the HTLV-1 Endemic

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    Human T-cell lymphotropic virus type 1 (HTLV-1) is the causative agent of Adult T-Cell Leukemia/Lymphoma (ATL), the Tropical Spastic Paraparesis/HTLV-1-associated Myelopathy (TSP/HAM) and other inflammatory diseases, including dermatitis, uveitis, and myositis. It is estimated that 2–8% of the infected persons will develop a HTLV-1-associated disease during their lifetimes, frequently TSP/HAM. Thus far, there is not a specific treatment to this progressive and chronic disease. HTLV-1 has means of three transmission: (i) from mother to child during prolonged breastfeeding, (ii) between sexual partners and (iii) through blood transfusion. HTLV-1 has been characterized in 7 subtypes and the geographical distribution and the clinical impact of this infection is not well known, mainly in African population. HTLV-1 is endemic in sub-Saharan Africa. Mozambique is a country of southeastern Africa where TSP/HAM cases were reported. Recently, our group estimated the HTLV prevalence among Mozambican blood donors as 0.9%. In this work we performed a genetic analysis of HTLV-1 in blood donors and HIV/HTLV co-infected patients from Maputo, Mozambique. Our results showed the presence of three HTLV-1 clusters within the Cosmopolitan/Transcontinental subtype/subgroup. The differential rates of HIV-1/HTLV-1 co-infection in the three HTLV-1 clusters demonstrated the dynamic of the two viruses and the need for implementation of control measures focusing on both retroviruses

    A people-centred perspective on climate change, environmental stress, and livelihood resilience in Bangladesh

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    The Ganges–Brahmaputra delta enables Bangladesh to sustain a dense population, but it also exposes people to natural hazards. This article presents findings from the Gibika project, which researches livelihood resilience in seven study sites across Bangladesh. This study aims to understand how people in the study sites build resilience against environmental stresses, such as cyclones, floods, riverbank erosion, and drought, and in what ways their strategies sometimes fail. The article applies a new methodology for studying people’s decision making in risk-prone environments: the personal Livelihood History interviews (N = 28). The findings show how environmental stress, shocks, and disturbances affect people’s livelihood resilience and why adaptation measures can be unsuccessful. Floods, riverbank erosion, and droughts cause damage to agricultural lands, crops, houses, and properties. People manage to adapt by modifying their agricultural practices, switching to alternative livelihoods, or using migration as an adaptive strategy. In the coastal study sites, cyclones are a severe hazard. The study reveals that when a cyclone approaches, people sometimes choose not to evacuate: they put their lives at risk to protect their livelihoods and properties. Future policy and adaptation planning must use lessons learned from people currently facing environmental stress and shocks
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