30 research outputs found

    Behavioral changes in mice caused by Toxoplasma gondii invasion of brain

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    Toxoplasma gondii, a protozoan parasite, is capable of infecting a broad range of intermediate warm-blooded hosts including humans. The parasite undergoes sexual reproduction resulting in genetic variability only in the intestine of the definitive host (a member of the cat family). The parasite seems to be capable of altering the natural behavior of the host to favor its transmission in the environment. The aim of this study was to evaluate the number of parasite cysts formed in the hippocampus and amygdala of experimentally infected mice as these regions are involved in defense behaviors control and emotion processing, and to assess the influence of the infection on mice behavior. The obtained results revealed the presence of parasite cysts both in the hippocampus and the amygdala of infected mice; however, no clear region-dependent distribution was observed. Furthermore, infected mice showed significantly diminished exploratory activity described by climbing and rearing, smaller preference for the central, more exposed part of the OF arena and engaged in less grooming behavior compared to uninfected controls

    Vaccines against toxoplasma gondii : challenges and opportunities

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    Development of vaccines against Toxoplasma gondii infection in humans is of high priority, given the high burden of disease in some areas of the world like South America, and the lack of effective drugs with few adverse effects. Rodent models have been used in research on vaccines against T. gondii over the past decades. However, regardless of the vaccine construct, the vaccines have not been able to induce protective immunity when the organism is challenged with T. gondii, either directly or via a vector. Only a few live, attenuated T. gondii strains used for immunization have been able to confer protective immunity, which is measured by a lack of tissue cysts after challenge. Furthermore, challenge with low virulence strains, especially strains with genotype II, will probably be insufficient to provide protection against the more virulent T. gondii strains, such as those with genotypes I or II, or those genotypes from South America not belonging to genotype I, II or III. Future studies should use animal models besides rodents, and challenges should be performed with at least one genotype II T. gondii and one of the more virulent genotypes. Endpoints like maternal-foetal transmission and prevention of eye disease are important in addition to the traditional endpoint of survival or reduction in numbers of brain cysts after challenge

    Detailed geomorphological map of Narwiański National Park with its buffer zone in scale 1:25000

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    As GIS is becoming more and more popular and available for its users it finds new implementation in many fields of knowledge and areas of life and business. It is now used in government, research Institutes, Universities and by private companies. Geographic Information System stand by remote sensing is more often used in monitoring and researching Environment. Testing GIS and remote sensing to actualize and preparing maps gave very good effects. That was the reason for using this solution for shape researching and creating geomorphological maps. The purpose of research was to create detailed geomorphological map of Narew National Park and its buffer zone in scale 1:25 000 using remote sensing (spectroscopy images), GIS programs, available maps and fi eld research carried out in the National Park. Narew National Park is located in Podlaskie Voivodeship, in North-Eastern Poland, traversed by the Narew River. The total area of the Park is 73.5 square kilometres of which only 20.57 km² is state-owned. Narew National Park was created in 1996. The area covered by the park is the Upper Narew Valley, a very swampy area. The methodology of map preparation was composed from 3 stages: Stage 1 – introductory geomorphologic sketch Stage 2 – preparing geomorphologic map in scale 1:25000 Stage 3 – Composition of map – preparing for printing The methodology of research didn’t include stereographic images. The alternative solution was interpretation of mosaic of spectroscopy images putted on DTM with 10 times superiority. Superiority was essential because height differences on the research area are rather small (only 50 m between the highest and the lowest point). The interpretation of boundaries between forms was carried out on DTM products, which were: hypsometric map, slopes and shaded relief. New solution was also the usage of color infrared images which was until this research used only in investigating plants and their diseases and also in hydrology. Interesting solution was the development of photointerpretaion key in which 3-D images were used (generated from DTM). This was great opportunity to visualize shape and spatial relation between geomorphologic forms. It was also very helpful in stating the origin of the forms. What is more authors examined new form of presenting geomorphologic content. The impression of mallable picture was achieved by putting geomorphological map on the image of slopes, generated from DTM. After the research few conclusions were made. 1. Color infrared images are very useful in relief exploration, mainly because: convex form, in which water table is deeper, are brighter on the satellite image than concave forms, in which water table is lower, emphasis of the shadow is very useful for distinguishing excavation, the absorption of infra-red radiation by water caused that every water body is very well seen, for example water in Narew riverbed, oxbow lake and other lakes. 2. DTM and maps which can be generated from it can replace topographic map and long and expensive terrain studies. 3. GIS offers programs which are useful not only in map preparation but also in the process of its composition. Literature studies and presented research lead to the statement that relief of researched area was formed in the close of Wolstonian Stage (in Polish: Zlodowacenie Środkowopolskie) and it was denudated in latest time of Pleistocene and Holocene

    Studies on carbon exchange in grassland areas

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    The paper presents the preliminary results of the task in the framework of ongoing project FINEGRASS “Effect of climatic changes on grassland growth, its water conditions and biomass” funded by the Polish-Norwegian Research Programme. The objective of this task is the assessment of carbon exchange in grassland areas using in-situ and remote sensing data. Grasslands are very sensitive ecosystem where significant changes of the carbon balance occur under different climate change, where grasslands either sequestrate or become the sources of carbon. The study was conducted in the years 2014–2015 at Wielkopolska Region, Biebrza River Valley, and Pieniny Mountains test sites, that cover three following grassland types: lowland non–valley, lowland valley, and mountainous. The paper presents in-situ and microwave and optical satellite observations to quantify relationships between soil-vegetation parameters that influence spatial and temporal variability of carbon fluxes over these areas. The next step of the study is the application of satellite data acquired in optical and microwave spectrum to develop method for the assessment of carbon fluxes

    Biophysical Parameters Assessed from Microwaveand Optical Data

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    The study has been carried out at Biebrza Wetlands situated in the N-E part of Poland, a NATURA 2000 and Ramsar Convention test site in 2003-2009. It is one of the largest in Europe natural rich biotope with the large amount of unique species of flora and important zone for nesting and wintering for fauna. Data from microwave and optical satellite images and soil-vegetation ground measurements were analyzed to develop methods for monitoring and mapping biophysical parameters. Satellite data applied for the study included: ENVISAT.ASAR, ENVISAT.MERIS, ALOS.PALSAR, ALOS.AVNIR-2, and NOAA.AVHRR data. Optical images were used for classification of wetlands communities and calculation of vegetation index NDVI. Also, latent heat flux has been calculated using NOAA.AVHRR data and meteorological data. Microwave images acquired in different modes (ASAR IS2 and IS6, ALPSR.FBD) and polarizations (HH, HV, VV) were used for assessment and mapping of Leaf Area Index (LAI) and soil moisture (SM) for every habitat classified from optical images. Backscattering coefficient calculated from ALOS.PALSAR HV and ENVISAT.ASAR IS6 VV was applied for assessment of vegetation bio-parameters. Backscattering coefficient calculated from ALOS.PALSAR.FBD HH and ENVISAT.ASAR HH IS2 was used for SM assessment. The study was conducted in the framework of ESA PECS project No 98101 and ESA PI projects: C1P.7389 and AOALO.3742

    Modeling of net ecosystem exchange (nee) at wetlands applying remote sensing

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    W artykule przedstawiono wyniki badań nad modelowaniem wymiany netto ekosystemu (NEE – ang. Net Ecosystem Exchange) bagiennego na przykładzie doliny Biebrzy z wykorzystaniem zdjęć satelitarnych i danych z pomiarów naziemnych z lat 2011–2015. Przeprowadzono szczegółową analizę zastosowania zdjęć optycznych i radarowych do uzyskania charakterystyk roślinno-wilgotnościowych wpływających na wymianę węgla. W wyniku przeprowadzonych analiz opracowano modele szacowania NEE, w których zastosowano opracowane na podstawie danych satelitarnych następujące parametry: wilgotność gleby (WG), zawartość wody w roślinach (WR). Do analizy WG i WR został zastosowany współczynnik wstecznego rozpraszania (σº) obliczony z sygnału zarejestrowanego w zakresie mikrofalowym przez urządzenia SAR (ang. Synthetic Aperture Radar) dla różnych polaryzacji fal. Prace badawcze zmierzające do określenia wielkości wymiany węgla oraz jego zróżnicowania przestrzennego i czasowego, przeprowadzone z uwzględnieniem informacji o pokrywie roślinnej i wilgotności gleby uzyskanych z danych satelitarnych, są ważne dla monitorowania ekosystemów bagiennych.The article presents results of the study on modeling Net Ecosystem Exchange (NEE) in the wetland ecosystem using remote sensing and in-situ data. The study has been conducted in Biebrza Valley for the years 2011–2015. The analysis of application of optical and microwave images for the assessment of vegetation-moisture conditions influenced carbon exchange has been performed. The impact of soil moisture and type of vegetation habitat on CO2 flux in wetland ecosystems has been analyzed to develop NEE models. Soil moisture (WG) and vegetation water content (WR) have been correlated with backscattering coefficient (σº) calculated from the signal registered by microwave satellites in different wave polarization. The research was focused on the assessment of carbon balance in time and space taking into account vegetation cover and soil moisture derived from satellite data. The research is important for monitoring wetland ecosystem
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