511 research outputs found
Regional White Matter Atrophy Correlates with Spike Activity in Encephalopathy Related to Status Epilepticus During Slow Sleep (ESES) After Early Thalamic Lesions
Encephalopathy related to Status Epilepticus during slow Sleep (ESES) is an age-related, epileptic syndrome, which associates cognitive/behavioral disturbances with a peculiar pattern of spike activity. One promising line of research is the study of ESES in cases of early thalamic lesions. We studied 7 ESES patients with unilateral thalamic lesions using magnetic resonance imaging to assess regional white matter (WM) and thalamic nuclei volume differences, and long-term electroencephalogram recordings to localize the epileptogenic cortex. N170 event-related potentials were used to demonstrate the dysfunctional character of the WM abnormalities. Diffusion-weighted images in a subset of 4 patients were used to parcellate the thalamus and evaluate volume asymmetries, based on cortical connectivity. Large WM regional atrophy in the hemisphere with the thalamic lesion was associated with both cortical dysfunction and epileptic activity. A correlation was demonstrated between lesions in the pulvinar and the mediodorsal thalamic nuclei and WM atrophy of the corresponding cortical projection areas. We propose that these abnormalities are due to the widespread structural disconnection produced by the thalamic lesions associated to a yet unknown age-dependent factor. Further exploration of WM regional atrophy association with the spike activity in other etiologies could lend support to the cortical disconnection role in ESES genesis.info:eu-repo/semantics/publishedVersio
A null biogeographic test for assessing ecological niche evolution
AIMS: Quantification of the degree to which ecological niches change over evolutionary timescales is important for deepening our understanding of evolutionary and ecological processes.
Phylogenetic niche conservatism (PNC) is when closely related species differ less ecologically than expected by chance, whereas Phylogenetic Niche Divergence (PND) is when closely related species differ more ecologically than expected by chance. We present a new null model to test for PNC and PND (the RTR significance test), which we combine with a novel metric for quantifying niche overlap
LOCATION: Europe, North America and Madagascar.
METHODS: The RTR null model comprises many thousands of replicates generated by randomly translocating and rotating the set of occurrence records for two populations (e.g.,sister species) while maintaining the spatial configuration between all occurrences within each replicate. For each replicate we calculate niche overlap as the proportion of the combined niche breadth that is shared by the two species, averaged over n environmental dimensions.
This approach enables us to test whether the observed niche overlap is more or less than expected by chance given the environmental conditions present in the study area. We test the performance of our approach in comparison to other methods using both simulated and real case scenarios, including crested newts in Europe, pocket gophers in North America, and lemurs in Madagascar.
RESULTS: We find that our measure of niche overlap performs better than other metrics in an artificial simulation scenario, and we find evidence for both PNC and PND in our case studies for Europe, North America and Madagascar. Our results demonstrate that both the RTR significance test and the novel metric of niche overlap are consistent with evolutionary theory and are suitable methods to test for PNC and PND.
MAIN CONCLUSIONS:
We make available scripts to implement the RTR test and metric of niche overlap, and expect that the methods will prove useful for addressing a broad set of questions relating to ecological niche evolution and speciation, particularly for restricted-range species for which few known occurrence records are available
Sorteio intradomiciliar em inquéritos de saúde
OBJETIVO : Comparar a eficiência e a acurácia de delineamentos de amostragem com e sem sorteio intradomiciliar em inquéritos de saúde. MÉTODOS : Com base nos dados de um inquérito realizado na Baixada Santista, SP, entre 2006 e 2007, foram retiradas 1.000 amostras sob cada um dos delineamentos e, em cada amostra, foram obtidas estimativas para pessoas de 18 a 59 anos de idade e de 18 anos e mais. Sob o primeiro, foram sorteados 40 setores censitários, 12 domicílios por setor e uma pessoa por domicílio. Na análise, os dados foram ponderados pelo número de adultos residentes nos domicílios. Sob o segundo, foram sorteados 40 setores, seis domicílios por setor para o grupo de 18 a 59 anos de idade e cinco ou seis domicílios para o grupo de 18 anos e mais. Não houve sorteio dentro do domicílio. Medidas de precisão e de vício das estimativas de proporção para 11 indicadores foram calculadas nos dois conjuntos finais das amostras selecionadas para os dois tipos de delineamentos. Estes foram comparados por meio das medidas relativas: coeficiente de variação, razão vício/média, razão vício/erro padrão e erro quadrático médio relativo. O custo foi comparado considerando custo básico por pessoa, custo por domicílio e números de pessoas e domicílios. RESULTADOS : Os vícios mostraram-se desprezíveis nos dois delineamentos. A precisão foi maior para o delineamento sem sorteio e o custo foi menor. CONCLUSÕES : O delineamento sem sorteio intradomicilar mostrou-se superior em termos de eficiência e acurácia, devendo ser a opção preferencial do pesquisador. O sorteio de moradores deve ser adotado quando houver razões referentes ao objeto de estudo que possam levar à introdução de vícios nas respostas dos entrevistados no caso de vários moradores responderem ao questionário proposto
Functions, organization and etiology. A reply to Artiga and Martinez
International audienceWe reply to Artiga and Martinez's claim according to which the organizational account of cross-generation functions implies a backward looking interpretation of etiology, just as standard etiological theories of function do. We argue that Artiga and Martinez's claim stems from a fundamental misunderstanding about the notion of " closure " , on which the organizational account relies. In particular, they incorrectly assume that the system, which is relevant for ascribing cross-generation organizational function, is the lineage. In contrast, we recall that organizational closure refers to a relational description of a network of mutual dependencies, abstracted from time, in which production relations are irrelevant. From an organizational perspective, ascribing a function to an entity means locating it in the abstract system that realizes closure. In particular, the position of each entity within the relational system conveys an etiological explanation of its existence, because of its dependence on the effects exerted by other entities subject to closure. Because of the abstract relational nature of closure, we maintain that the organizational account of functions does not endorse a backward looking interpretation of etiology. As a consequence, it does not fall prey of epiphenomenalism
Delivery of a Chlamydial Adhesin N-PmpC Subunit Vaccine to the Ocular Mucosa Using Particulate Carriers
Trachoma, caused by the intracellular bacterium Chlamydia trachomatis (Ct), remains the world's leading preventable infectious cause of blindness. Recent attempts to develop effective vaccines rely on modified chlamydial antigen delivery platforms. As the mechanisms engaged in the pathology of the disease are not fully understood, designing a subunit vaccine specific to chlamydial antigens could improve safety for human use. We propose the delivery of chlamydia-specific antigens to the ocular mucosa using particulate carriers, bacterial ghosts (BGs). We therefore characterized humoral and cellular immune responses after conjunctival and subcutaneous immunization with a N-terminal portion (amino acid 1-893) of the chlamydial polymorphic membrane protein C (PmpC) of Ct serovar B, expressed in probiotic Escherichia coli Nissle 1917 bacterial ghosts (EcN BGs) in BALB/cmice. Three immunizations were performed at two-week intervals, and the immune responses were evaluated two weeks after the final immunization in mice. In a guinea pig model of ocular infection animals were immunized in the same manner as the mice, and protection against challenge was assessed two weeks after the last immunization. N-PmpC was successfully expressed within BGs and delivery to the ocularmucosa was well tolerated without signs of inflammation. N-PmpC- specific mucosal IgA levels in tears yielded significantly increased levels in the group immunized via the conjunctiva compared with the subcutaneously immunized mice. Immunization with N-PmpC EcN BGs via both immunization routes prompted the establishment of an N-PmpC-specific IFN gamma immune response. Immunization via the conjunctiva resulted in a decrease in intensity of the transitional inflammatory reaction in conjunctiva of challenged guinea pigs compared with subcutaneously and non-immunized animals. The delivery of the chlamydial subunit vaccine to the ocular mucosa using a particulate carrier, such as BGs, induced both humoral and cellular immune responses. Further investigations are needed to improve the immunization scheme and dosage
Adherence to anti-hypertensive treatment within a chronic disease management program: A longitudinal, retrospective study
Objective This study assessed pharmacological treatment adherence using the Morisky-Green Test and identified related variables. Method A longitudinal and retrospective study examined 283 patients with hypertension (62.5% women, 73.4 [10.9] years old) who were being monitored by a chronic disease management program for 17 months between 2011 and 2012. Nurses performed all the actions of the program, which consisted of advice via telephone and periodic home visits based on the risk stratification of the patients. Results A significant increase in treatment adherence (25.1% vs. 85.5%) and a decrease in blood pressure were observed (p<0.05). Patients with hypertension and chronic renal failure as well as those treated using angiotensin-converting enzyme inhibitors were the most adherent (p<0.05). Patients with hypertension who received angiotensin receptor blockers were less adherent (p<0.05). Conclusions Strategies such as nurse-performed chronic disease management can increase adherence to anti-hypertensive treatment and therefore contribute to the control of blood pressure, minimizing the morbidity profiles of patients with hypertension
The genomes of two key bumblebee species with primitive eusocial organization
Background: The shift from solitary to social behavior is one of the major evolutionary transitions. Primitively eusocial bumblebees are uniquely placed to illuminate the evolution of highly eusocial insect societies. Bumblebees are also invaluable natural and agricultural pollinators, and there is widespread concern over recent population declines in some species. High-quality genomic data will inform key aspects of bumblebee biology, including susceptibility to implicated population viability threats. Results: We report the high quality draft genome sequences of Bombus terrestris and Bombus impatiens, two ecologically dominant bumblebees and widely utilized study species. Comparing these new genomes to those of the highly eusocial honeybee Apis mellifera and other Hymenoptera, we identify deeply conserved similarities, as well as novelties key to the biology of these organisms. Some honeybee genome features thought to underpin advanced eusociality are also present in bumblebees, indicating an earlier evolution in the bee lineage. Xenobiotic detoxification and immune genes are similarly depauperate in bumblebees and honeybees, and multiple categories of genes linked to social organization, including development and behavior, show high conservation. Key differences identified include a bias in bumblebee chemoreception towards gustation from olfaction, and striking differences in microRNAs, potentially responsible for gene regulation underlying social and other traits. Conclusions: These two bumblebee genomes provide a foundation for post-genomic research on these key pollinators and insect societies. Overall, gene repertoires suggest that the route to advanced eusociality in bees was mediated by many small changes in many genes and processes, and not by notable expansion or depauperation
PHLEBOTOMINE FAUNA (DIPTERA: PSYCHODIDAE) IN AN AREA OF FISHING TOURISM IN CENTRAL-WESTERN BRAZIL
The aim of this study was to identify behavioral aspects of the sandfly fauna of a fishing tourism area in the municipality of Bonito (MS). Monthly captures were undertaken from December 2009 to November 2010, using automatic CDC type light traps, from 18h00 to 06h00, in a forested area, a savannah area, peridomiciles and animal shelters near peridomiciliary areas. Nyssomyia whitmani was the most frequent out of a total of 6,699 specimens collected, belonging to 16 species, followed by Psathyromyia bigeniculata and Lutzomyia longipalpis, found in all the environments investigated, though in their greatest numbers in the animal shelters. Ny. whitmani exhibited its highest frequencies during the dry months, coincident with the fishing season, when the risk of transmission of cutaneous leishmaniasis for tourists and inhabitants increases. Noteworthy was the finding of two species naturally infected by flagellates: Ny. whitmani and Pa. bigeniculata. The local population and visiting tourists should be warned of the threat posed by leishmaniasis and the health authorities alerted to the need for adopting environmental sanitary measures, especially regarding such animal shelters as they seem to provide favorable conditions to the proliferation, maintenance and breeding opportunities of phlebotomines
"A convenient truth": air travel passengers' willingness to pay to offset their CO2 emissions
Several economic reviews demonstrate the substantial costs related to climate
change and consequently call for early action. These reviews, however, have been limited
to measuring ‘objective’ risks and expected material damage related to climate change. The
‘subjective’ perceived risk of climate change and society’s willingness to pay (WTP) to
avoid these risks are expected to provide an important additional motivation for direct
action. We investigate whether and why air travel passengers—an increasingly important
source of greenhouse gas emissions—are supportive of measures that increase the cost of
their travel based on the polluter pays principle and compensate the damage caused by their
flight. Compared to the results of the few previous studies that have elicited WTP estimates
for climate policy more generally, our results appear to be at the lower end of the scale,
while a comparison to estimates of the social cost of carbon shows that the average WTP
estimate in this study is close to the estimated marginal damage cost. Although significant
differences are found between travellers from Europe, North America, Asia and the rest of
the world, we show that there exists a substantial demand for climate change mitigation
action. The positive risk premium over and above the expected property damage cost
assessments should be accounted for more explicitly in economic reviews as it will add to
the burden of proof of direct action. Measurements of passenger WTP will help policy
makers to design effective financial instruments aimed at discouraging climate-unfriendly
travel activities as well as to generate funds for the measures directed at climate change
mitigation and adaptation. Based on stated WTP by travellers to offset their greenhouse gas
emissions, funds in the order of magnitude of €23 billion could be generated annually to
finance climate change mitigation activities
HIV-1 Promotes Intake of Leishmania Parasites by Enhancing Phosphatidylserine-Mediated, CD91/LRP-1-Dependent Phagocytosis in Human Macrophages
Over the past decade, the number of reported human immunodeficiency virus type-1 (HIV-1)/Leishmania co-infections has risen dramatically, particularly in regions where both diseases are endemic. Although it is known that HIV-1 infection leads to an increase in susceptibility to Leishmania infection and leishmaniasis relapse, little remains known on how HIV-1 contributes to Leishmania parasitaemia. Both pathogens infect human macrophages, and the intracellular growth of Leishmania is increased by HIV-1 in co-infected cultures. We now report that uninfected bystander cells, not macrophages productively infected with HIV-1, account for enhanced phagocytosis and higher multiplication of Leishmania parasites. This effect can be driven by HIV-1 Tat protein and transforming growth factor-beta (TGF-β). Furthermore, we show for the first time that HIV-1 infection increases surface expression of phosphatidylserine receptor CD91/LRP-1 on human macrophages, thereby leading to a Leishmania uptake by uninfected bystander cells in HIV-1-infected macrophage populations. The more important internalization of parasites is due to interactions between the scavenger receptor CD91/LRP-1 and phosphatidylserine residues exposed at the surface of Leishmania. We determined also that enhanced CD91/LRP-1 surface expression occurs rapidly following HIV-1 infection, and is triggered by the activation of extracellular TGF-β. Thus, these results establish an intricate link between HIV-1 infection, Tat, surface CD91/LRP-1, TGF-β, and enhanced Leishmania phosphatidylserine-mediated phagocytosis
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