462 research outputs found
Trace element analysis provides insight into the diets of early Late Miocene ungulates from the Rudabánya II locality (Hungary)
The early Late Miocene vertebrate locality of Rudabánya II (R. II) in northeastern Hungary preserves an abundance of forest-adapted ungulate species. To better understand the ecological relationships within this ancient ecosystem, we used analysis of enamel strontium/calcium (Sr/Ca) ratios to infer dietary preferences. The goals of the analysis were to: i) determine whether these ungulate species specialized in specific plants or plant parts; ii) discern whether the Sr/Ca ratios support what was previously suggested about the ecology of these species; and iii) evaluate the factors that may have acted to promote coexistence within this diverse community of predominantly browsing herbivores. Results show significant differences in the diets of the sampled species. The highest Sr/Ca ratios were displayed by the suids Parachleuastochoerus kretzoii [B1] and Propotamochoerus palaeochoerus implying a preference for Sr-rich underground plant parts. Elevated Sr/Ca ratios yielded by the cervid Lucentia aff. pierensis and equid Hippotherium intrans are indicative of intermediate feeding. The bovid Miotragocerus sp. showed higher Sr/Ca ratios than the gomphothere Tetralophodon longirostris, which is incongruent with morphological and stable isotope data, and suggested browsing by both taxa. This finding is likely the result of a difference in digestive physiology (ruminant vs. monogastric) rather than a difference in dietary behaviour. The lowest Sr/Ca ratios were displayed by the traguild Dorcatherium naui and moschid Micromeryx flourensianussuggesting a preference for Sr-poor fruits. Resource specialization and partitioning within the local environment likely acted to decrease interspecific competition and promote coexistence within the diverse ungulate community at R. II
A ducted wind turbine simulation model for building simulation
Power production is shifting away from centralized generation plants to production of heat and power at the point of demand. A technology that may play a part in this shift is the ducted wind turbine (DWT). The emergence of small building integrated micro turbines opens up the possibility of utilizing the differential pressures occurring around buildings for local power production. This paper describes work to develop and test a simple mathematical model of a ducted wind turbine and its integration within a building simulation tool. A case study in which the simulation model will be used to analyse of the likely power output from a building incorporating ducted wind turbines within the façade is also presented
Drivers of grassland loss in Hungary during the post-socialist transformation (1987–1999)
The increase in the speed of land-cover change experienced worldwide is becoming a growing
concern. Major socio-economic transitions, such as the breakdown of socialism in Europe, may
lead to particularly high rates of landscape transformations. In this paper we examined the loss of semi-natural grasslands in Hungary between 1987 and 1999. We studied the relationship between 9
potential driving forces and the fate of grasslands using logistic GLMs.
Grassland loss was found to be very high (1.31 % per year), which is far higher than either before
or after this period. The most influential predictors of grassland loss were environmental and
landscape characteristics (soil type, area of remnant grassland patches), and the socio-economic context (distance to paved road, and nearest settlement, human population density). Several
processes and relationships can only be understood from a historical perspective (e.g. large extent
of afforestation, strong decrease of soil water table). Grassland loss during the study period
emerged as a consequence of survival strategies of individual farmers seeking adaptation to the
changing environmental and socio-economic conditions, and not urbanization and agricultural intensification which are the main underlying drivers for the ongoing landscape transformations in
most parts of the developed world.
Though globalization increasingly influences local land use decisions , reconstructing and
modelling recent landscape changes cannot be done without a proper understanding of local history
and culture. Our analysis shows the importance of large-area yet high resolution landscape change research, which may reveal unexpected patterns of land cover change, undetected at coarser scales
Methods of interception of voice communication
Bakalářská práce porovnává dostupné metody odposlechu a možnosti ochrany informací a soukromí.
V první části se zabývá právními předpisy, které člověka v České republice
proti odposlechu chrání a jaká práva odposlech zasáhne, v případě nelegálního využití.
Další část je věnována zvoleným odposlechům, kde jsou pospány jednotlivé metody odposlechů a jejich technologické parametry. Cílem této části je porovnat techniky
a technologie používané k odposlechu hlasové komunikace a její finanční náročnost.
Dále má práce popisuje zásady obranné technické prohlídky, která pomáhá
při odhalování nelegálních odposlechů. Část práce se věnuje předpokládanému vývoji odposlechu a rizikům spojenými s nevědomostmi.compares available eavesdropping methods and options
for information and privacy protection. The first part deals with legal regulations protecting individuals against eavesdropping in the Czech Republic and outlines the rights that eavesdropping may affect in case of illegal use. The subsequent section focuses on selected eavesdropping techniques, detailing their technological parameters. The aim of this part
is to compare the techniques and technologies used for eavesdropping on voice communication and their financial requirements. Furthermore, the thesis describes
the principles of defensive technical inspections, which aid in detecting illegal eavesdropping activities. A portion of the work addresses the anticipated development
of eavesdropping methods and associated risks arising from unawareness.060 - Katedra bezpečnostních služebdobř
A Holistic Landscape Description Reveals That Landscape Configuration Changes More over Time than Composition: Implications for Landscape Ecology Studies
International audienceBackground: Space-for-time substitution—that is, the assumption that spatial variations of a system can explain and predict the effect of temporal variations—is widely used in ecology. However, it is questionable whether it can validly be used to explain changes in biodiversity over time in response to land-cover changes.Hypothesis: ere, we hypothesize that different temporal vs spatial trajectories of landscape composition and configuration may limit space-for-time substitution in landscape ecology. Land-cover conversion changes not just the surface areas given over to particular types of land cover, but also affects isolation, patch size and heterogeneity. This means that a small change in land cover over time may have only minor repercussions on landscape composition but potentially major consequences for landscape configuration.Methods: sing land-cover maps of the Paris region for 1982 and 2003, we made a holistic description of the landscape disentangling landscape composition from configuration. After controlling for spatial variations, we analyzed and compared the amplitudes of changes in landscape composition and configuration over time.Results: For comparable spatial variations, landscape configuration varied more than twice as much as composition over time. Temporal changes in composition and configuration were not always spatially matched.Significance: The fact that landscape composition and configuration do not vary equally in space and time calls into question the use of space-for-time substitution in landscape ecology studies. The instability of landscapes over time appears to be attributable to configurational changes in the main. This may go some way to explaining why the landscape variables that account for changes over time in biodiversity are not the same ones that account for the spatial distribution of biodiversity
Hypsodonty, horses, and the spread of C 4 grasses during the middle Miocene in southern California
ABSTRACT Background: C 4 grasses were not abundant in North America during the middle Miocene (c. 15 Ma). They did not become abundant until around 7 Ma. One can analyse stable carbon (
High variability within pet foods prevents the identification of native species in pet cats' diets using isotopic evaluation
Domestic cats preying on wildlife is a frequent conservation concern but typical approaches for assessing impacts rely on owner reports of prey returned home, which can be biased by inaccurate reporting or by cats consuming prey instead of bringing it home. Isotopes offer an alternative way to quantify broad differences in animal diets. By obtaining samples of pet food from cat owners we predicted that we would have high power to identify cats feeding on wild birds or mammals, given that pet food is thought to have higher C isotope values, due to the pervasive use of corn and/or corn by-products as food ingredients, than native prey. We worked with citizen scientists to quantify the isotopes of 202 cat hair samples and 239 pet food samples from the US and UK. We also characterized the isotopes of 11 likely native prey species from the southeastern US and used mixing models to assess the diet of 47 cats from the same region. Variation in C and N isotope values for cat food was very high, even within the same brand/flavor, suggesting that pet food manufacturers use a wide range of ingredients, and that these may change over time. Cat food and cat hair from the UK had lower C values than the US, presumably reflecting differences in the amount of corn used in the food chains of the two countries. This high variation in pet food reduced our ability to classify cats as hunters of native prey, such that only 43% of the animals could be confidently assigned. If feral or free ranging cats were considered, this uncertainty would be even higher as pet food types would be unknown. Our results question the general assumption that anthropogenic foods always have high C isotope values, because of the high variability we documented within one product type (cat food) and between countries (US vs. UK), and emphasize the need to test a variety of standards before making conclusions from isotope ecology studies
Vulvodynia is not created equally: empirical classification of women with vulvodynia
Background: Vulvodynia classification is based on the sensory dimensions of pain and does not include psychological factors associated with the pain experience and treatment outcomes. Previous work has shown that individuals with chronic pain can be classified into subgroups based on pain sensitivity, psychological distress, mood, and symptom severity. Objective: The aim of this study was to identify distinct subgroups of women with vulvodynia enrolled in the National Vulvodynia Registry. We hypothesized that women with vulvodynia can be clustered into subgroups based on distress and pain sensitivity. Design: A cross-sectional study. Methods: We conducted an exploratory hierarchical agglomerative cluster analysis using Ward’s cluster method and squared Euclidean distances to identify unique subgroups based on baseline psychological distress and pain sensitivity. The variables included the catastrophizing subscale of the Coping Strategies Questionnaire, the Beck Depression Inventory, the State Trait Anxiety Index-Trait scale, McGill Pain Questionnaire-Affective subscale, and vulvar and pelvic muscle pressure pain sensitivity. Subjects: Eight sites enrolled women who presented with vaginal or vulval pain of at least 3-month duration. Results: Two distinct subgroups, high pain sensitivity with high distress (n=27) and low pain sensitivity with low distress (n=100), emerged from the cluster analysis. Validation indicated that subgroups differed in terms of clinical pain intensity, sensory aspects of pain, and intercourse pain. Conclusion: Empirical classification indicates that unique subgroups exist in women with vulvodynia. Providers should be aware of the heterogeneity of this condition with respect to pain-related distress and pain sensitivity
Effects of Global Warming on Ancient Mammalian Communities and Their Environments
Current global warming affects the composition and dynamics of mammalian communities and can increase extinction risk; however, long-term effects of warming on mammals are less understood. Dietary reconstructions inferred from stable isotopes of fossil herbivorous mammalian tooth enamel document environmental and climatic changes in ancient ecosystems, including C(3)/C(4) transitions and relative seasonality.Here, we use stable carbon and oxygen isotopes preserved in fossil teeth to document the magnitude of mammalian dietary shifts and ancient floral change during geologically documented glacial and interglacial periods during the Pliocene (approximately 1.9 million years ago) and Pleistocene (approximately 1.3 million years ago) in Florida. Stable isotope data demonstrate increased aridity, increased C(4) grass consumption, inter-faunal dietary partitioning, increased isotopic niche breadth of mixed feeders, niche partitioning of phylogenetically similar taxa, and differences in relative seasonality with warming.Our data show that global warming resulted in dramatic vegetation and dietary changes even at lower latitudes (approximately 28 degrees N). Our results also question the use of models that predict the long term decline and extinction of species based on the assumption that niches are conserved over time. These findings have immediate relevance to clarifying possible biotic responses to current global warming in modern ecosystems
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