Low Holocene level (7700 to 3650 years ago) of Lake Titicaca (Bolivia)

Les premiers résultats des analyses sédimentologiques et paléontologiques de deux échantillons de sédiments du lac Titicaca indiquent que entre 7700 et 3650 ans B.P. le niveau lacustre pouvait descendre jusqu'à 50 m. au dessous du niveau actue

Prevalência da exposição ao fumo ambiental do tabaco em casa e do tabagismo na população Portuguesa – o estudo INAsma

ResumoIntroduçãoNeste estudo, pretendemos: 1) estimar a prevalência, na população portuguesa, da exposição ao fumo ambiental do tabaco em casa; 2) estimar a prevalência de tabagismo em Portugal; 3) identificar as características sociais e pessoais associadas ao tabagismo ou à exposição ao fumo ambiental do tabaco.MétodosEstudo transversal consistindo na aplicação, à população, a nível nacional, de questionário telefónico. Completaram a entrevista 6 003 indivíduos. A exposição ao fumo ambiental do tabaco em casa foi definida como a exposição, em casa, ao fumo do tabaco de, pelo menos, um fumador atual. Por fumador entendeu-se um indivíduo com ≥ 15 anos que fumou, pelo menos, um cigarro por dia durante um período de um ano; um fumador atual fumou no último mês.ResultadosReferiram exposição ao fumo ambiental do tabaco em casa 26,6% dos participantes (IC 95%: 25,5-27,7). Viver num agregado familiar constituído por ≥ 4 pessoas (OR=2,31; IC 95%: [1,81-2,96]), ser fumador atual (OR=7,29; IC 95%: [5,74-9,26]) ou ter asma atual (OR=2,06; IC 95%: [1,45-2,94]) associaram-se positivamente à exposição ao fumo ambiental do tabaco. Na análise estratificada por sexo, o efeito da asma atual manteve-se apenas nas mulheres.Atualmente, 19,0% (IC 95%: 18,0-20,0) da população portuguesa é fumadora e 17,2% (IC 95%: 16,2-18,2) são ex-fumadores. A prevalência de fumadores atuais é mais elevada nos homens do que nas mulheres (26,5 versus 12,2%, p<0,001). A probabilidade de ser um fumador atual foi maior nos homens, nas pessoas mais instruídas e nos indivíduos expostos, em casa, ao fumo ambiental do tabaco. Na análise estratificada por sexo, o efeito da escolaridade manteve-se apenas nas mulheres.ConclusãoA exposição ao fumo ambiental do tabaco em casa foi mais elevada do que a anteriormente publicada. Crianças/adolescentes e doentes com asma podem ter um risco de exposição ambiental mais elevado. Este estudo apoia uma tendência decrescente da prevalência de tabagismo nos homens portugueses, mas uma tendência crescente nas mulheres.AbstractBackgroundWe aimed to: 1) estimate the prevalence of exposure to environmental tobacco smoke (ETS) at home in the Portuguese population; 2) estimate tobacco smoking prevalence in Portugal; 3) identify social and personal characteristics associated with smoking or exposure to ETS.MethodsNationwide, cross-sectional, population-based telephone survey. Overall, 6003 individuals completed the interview. ETS exposure at home was defined as exposure to at least one current smoker at home. A smoker was defined as someone with 15 years or older, smoking at least 1 cigarette per day during a year; a current smoker (CS) smoked in the last month.ResultsExposure to ETS at home was reported by 26.6% (95%CI 25.5-27.7) of the participants. Living in households with ≥4 persons (OR=2.31; 95%CI[1.81-2.96]), being a current smoker (OR=7.29; 95%CI[5.74-9.26]) or having current asthma (OR=2.06; 95%CI[1.45-2.94]) were factors positively associated with ETS exposure. When analyzed by gender, the effect of current asthma was only relevant to females.Currently 19.0% (95%CI 18.0-20.0) of the Portuguese population smokes tobacco and 17.2% (95%CI 16.2-18.2) are ex-smokers. CS prevalence is higher in males than females (26.5%versus 12.2%, p<0,001). The odds of being a CS were higher for males, the more educated, and those exposed to ETS at home. When analyzed by gender, school education only affected females.ConclusionExposure to ETS at home was higher than previously reported. Children/adolescents and asthma patients may have a higher risk of exposure. This report endorses a decreasing trend in the prevalence of tobacco smoking in Portuguese males, but a tendency to increase in females

Integrated Assessment of CO2-Induced Acidification Lethal and Sub-Lethal Effects on Tropical Mussels Perna perna

Leakages of CO2 capture and storage systems from the seabed are able to cause significant adverse biological effects in marine species. Adult mussels were exposed to different CO2 enrichment scenarios (pH from 8.3 to 6.0) for 96 h, and endpoints (lysosomal membrane deterioration, lipid peroxidation and primary damages in DNA) were assessed. Mortality and reduced health status can occur after short exposure of the tropical mussel Perna perna to pH levels lower than 7.5. Results pointed out cytogenotoxic effects in the hemolymph and gills after 48 and 96 h of exposure, respectively. These findings should be considered when environmental monitoring approaches are performed in tropical marine areas employing CCS strategie

Embedding a Native State into a Random Heteropolymer Model: The Dynamic Approach

We study a random heteropolymer model with Langevin dynamics, in the supersymmetric formulation. Employing a procedure similar to one that has been used in static calculations, we construct an ensemble in which the affinity of the system for a native state is controlled by a "selection temperature" T0. In the limit of high T0, the model reduces to a random heteropolymer, while for T0-->0 the system is forced into the native state. Within the Gaussian variational approach that we employed previously for the random heteropolymer, we explore the phases of the system for large and small T0. For large T0, the system exhibits a (dynamical) spin glass phase, like that found for the random heteropolymer, below a temperature Tg. For small T0, we find an ordered phase, characterized by a nonzero overlap with the native state, below a temperature Tn \propto 1/T0 > Tg. However, the random-globule phase remains locally stable below Tn, down to the dynamical glass transition at Tg. Thus, in this model, folding is rapid for temperatures between Tg and Tn, but below Tg the system can get trapped in conformations uncorrelated with the native state. At a lower temperature, the ordered phase can also undergo a dynamical glass transition, splitting into substates separated by large barriers.Comment: 19 pages, revtex, 6 figure

From Linear to Nonlinear Response in Spin Glasses: Importance of Mean-Field-Theory Predictions

Deviations from spin-glass linear response in a single crystal Cu:Mn 1.5 at % are studied for a wide range of changes in magnetic field, $\Delta H$. Three quantities, the difference $TRM-(MFC-ZFC)$, the effective waiting time, $t_{w}^{eff}$, and the difference $TRM(t_{w})-TRM(t_{w}=0)$ are examined in our analysis. Three regimes of spin-glass behavior are observed as $\Delta H$ increases. Lines in the $(T,\Delta H)$ plane, corresponding to ``weak'' and ``strong'' violations of linear response under a change in magnetic field, are shown to have the same functional form as the de Almeida-Thouless critical line. Our results demonstrate the existence of a fundamental link between static and dynamic properties of spin glasses, predicted by the mean-field theory of aging phenomena.Comment: 9 pages, 10 figure

Structural glass on a lattice in the limit of infinite dimensions

We construct a mean field theory for the lattice model of a structural glass and solve it using the replica method and one step replica symmetry breaking ansatz; this theory becomes exact in the limit of infinite dimensions. Analyzing stability of this solution we conclude that the metastable states remain uncorrelated in a finite temperature range below the transition, but become correlated at sufficiently low temperature. We find dynamic and thermodynamic transition temperatures as functions of the density and construct a full thermodynamic description of a typical physical process in which the system gets trapped in one metastable state when cooled below vitrification temperature. We find that for such physical process the entropy and pressure at the glass transition are continuous across the transition while their temperature derivatives have jumps.Comment: 4 pages, 2 figure

Replica Symmetry Breaking Instability in the 2D XY model in a random field

We study the 2D vortex-free XY model in a random field, a model for randomly pinned flux lines in a plane. We construct controlled RG recursion relations which allow for replica symmetry breaking (RSB). The fixed point previously found by Cardy and Ostlund in the glass phase $T<T_c$ is {\it unstable} to RSB. The susceptibility $\chi$ associated to infinitesimal RSB perturbation in the high-temperature phase is found to diverge as $\chi \propto (T-T_c)^{-\gamma}$ when $T \rightarrow T_c^{+}$. This provides analytical evidence that RSB occurs in finite dimensional models. The physical consequences for the glass phase are discussed.Comment: 8 pages, REVTeX, LPTENS-94/2

The Neuroprotective Action of Amidated-Kyotorphin on Amyloid β Peptide-Induced Alzheimer’s Disease Pathophysiology

Kyotorphin (KTP, l-tyrosyl-l-arginine) is an endogenous dipeptide initially described to have analgesic properties. Recently, KTP was suggested to be an endogenous neuroprotective agent, namely for Alzheimer’s disease (AD). In fact, KTP levels were shown to be decreased in the cerebrospinal fluid of patients with AD, and recent data showed that intracerebroventricular (i.c.v.) injection of KTP ameliorates memory impairments in a sporadic rat model of AD. However, this administration route is far from being a suitable therapeutic strategy. Here, we evaluated if the blood-brain permeant KTP-derivative, KTP-NH2, when systemically administered, would be effective in preventing memory deficits in a sporadic AD animal model and if so, which would be the synaptic correlates of that action. The sporadic AD model was induced in male Wistar rats through i.c.v. injection of amyloid β peptide (Aβ). Animals were treated for 20 days with KTP-NH2 (32.3 mg/kg, intraperitoneally (i.p.), starting at day 3 after Aβ administration) before memory testing (Novel object recognition (NOR) and Y-maze (YM) tests). Animals were then sacrificed, and markers for gliosis were assessed by immunohistochemistry and Western blot analysis. Synaptic correlates were assessed by evaluating theta-burst induced long term potentiation (LTP) of field excitatory synaptic potentials (fEPSPs) recorded from hippocampal slices and cortical spine density analysis. In the absence of KTP-NH2 treatment, Aβ-injected rats had clear memory deficits, as assessed through NOR or YM tests. Importantly, these memory deficits were absent in Aβ-injected rats that had been treated with KTP-NH2, which scored in memory tests as control (sham i.c.v. injected) rats. No signs of gliosis could be detected at the end of the treatment in any group of animals. LTP magnitude was significantly impaired in hippocampal slices that had been incubated with Aβ oligomers (200 nM) in the absence of KTP-NH2. Co-incubation with KTP-NH2 (50 nM) rescued LTP toward control values. Similarly, Aβ caused a significant decrease in spine density in cortical neuronal cultures, and this was prevented by co-incubation with KTP-NH2 (50 nM). In conclusion, the present data demonstrate that i.p. KTP-NH2 treatment counteracts Aβ-induced memory impairments in an AD sporadic model, possibly through the rescuing of synaptic plasticity mechanisms.publishersversionpublishe

Exploring the genomic diversity of black yeasts and relatives (Chaetothyriales, Ascomycota)

The order Chaetothyriales (Pezizomycotina, Ascomycetes) harbours obligatorily melanised fungi and includes numerous etiologic agents of chromoblastomycosis, phaeohyphomycosis and other diseases of vertebrate hosts. Diseases range from mild cutaneous to fatal cerebral or disseminated infections and affect humans and cold-blooded animals globally. In addition, Chaetothyriales comprise species with aquatic, rock-inhabiting, ant-associated, and mycoparasitic life-styles, as well as species that tolerate toxic compounds, suggesting a high degree of versatile extremotolerance. To understand their biology and divergent niche occupation, we sequenced and annotated a set of 23 genomes of main the human opportunists within the Chaetothyriales as well as related environmental species. Our analyses included fungi with diverse life-styles, namely opportunistic pathogens and closely related saprobes, to identify genomic adaptations related to pathogenesis. Furthermore, ecological preferences of Chaetothyriales were analysed, in conjuncture with the order-level phylogeny based on conserved ribosomal genes. General characteristics, phylogenomic relationships, transposable elements, sex-related genes, protein family evolution, genes related to protein degradation (MEROPS), carbohydrate-active enzymes (CAZymes), melanin synthesis and secondary metabolism were investigated and compared between species. Genome assemblies varied from 25.81 Mb (Capronia coronata) to 43.03 Mb (Cladophialophora immunda). The bantiana-clade contained the highest number of predicted genes (12,817 on average) as well as larger genomes. We found a low content of mobile elements, with DNA transposons from Tc1/Mariner superfamily being the most abundant across analysed species. Additionally, we identified a reduction of carbohydrate degrading enzymes, specifically many of the Glycosyl Hydrolase (GH) class, while most of the Pectin Lyase (PL) genes were lost in etiological agents of chromoblastomycosis and phaeohyphomycosis. An expansion was found in protein degrading peptidase enzyme families S12 (serine-type D-Ala-D-Ala carboxypeptidases) and M38 (isoaspartyl dipeptidases). Based on genomic information, a wide range of abilities of melanin biosynthesis was revealed; genes related to metabolically distinct DHN, DOPA and pyomelanin pathways were identified. The MAT (MAting Type) locus and other sex-related genes were recognized in all 23 black fungi. Members of the asexual genera Fonsecaea and Cladophialophora appear to be heterothallic with a single copy of either MAT-1-1 or MAT-1-2 in each individual. All Capronia species are homothallic as both MAT1-1 and MAT 1-2 genes were found in each single genome. The genomic synteny of the MAT-locus flanking genes (SLA2-APN2-COX13) is not conserved in black fungi as is commonly observed in Eurotiomycetes, indicating a unique genomic context for MAT in those species. The heterokaryon (het) genes expansion associated with the low selective pressure at the MAT-locus suggests that a parasexual cycle may play an important role in generating diversity among those fungi