The evolution of the mass-metallicity relation in SDSS galaxies uncovered by astropaleontology

We have obtained the mass-metallicity (M-Z) relation at different lookback times for the same set of galaxies from the Sloan Digital Sky Survey, using the stellar metallicities estimated with our spectral synthesis code STARLIGHT. We have found that this relation steepens and spans a wider range in both mass and metallicity at higher redshifts. We have modelled the time evolution of stellar metallicity with a closed-box chemical evolution model, for galaxies of different types and masses. Our results suggest that the M-Z relation for galaxies with present-day stellar masses down to 10(10) M(circle dot) is mainly driven by the history of star formation and not by inflows or outflows.

Comparative range use by three Atlantic Forest understorey bird species in relation to forest fragmentation

In this paper, we report on range use patterns of birds in relation to tropical forest fragmentation. Between 2003 and 2005, three understorey passerine species were radio-tracked in five locations of a fragmented and in two locations of a contiguous forest landscape on the Atlantic Plateau of Sao Paulo in south-eastern Brazil. Standardized ten-day home ranges of 55 individuals were used to determine influences of landscape pattern, season, species, sex and age. In addition, total observed home ranges of 76 individuals were reported as minimum measures of spatial requirements of the species. Further, seasonal home ranges of recaptured individuals were compared to examine site fidelity. Chiroxiphia caudata, but not Pyriglena leucoptera or Sclerurus scansor, used home ranges more than twice as large in the fragmented versus contiguous forest. Home range sizes of C. caudata differed in relation to sex, age, breeding status and season. Seasonal home ranges greatly overlapped in both C. caudata and in S. scansor. Our results suggest that one response by some forest bird species to habitat fragmentation entails enlarging their home ranges to include several habitat fragments, whereas more habitat-sensitive species remain restricted to larger forest patches.

Relation of pretreatment sequence diversity in NS5A region of HCV genotype 1 with immune response between pegylated-INF/ribavirin therapy outcomes

Hepatitis C virus (HCV) infection frequently persists despite substantial virus-specific immune responses and the combination of pegylated interferon (INF)-alpha and ribavirin therapy. Major histocompatibility complex class I restricted CD8+ T cells are responsible for the control of viraemia in HCV infection, and several studies suggest protection against viral infection associated with specific HLAs. The reason for low rates of sustained viral response (SVR) in HCV patients remains unknown. Escape mutations in response to cytotoxic T lymphocyte are widely described; however, its influence in the treatment outcome is ill understood. Here, we investigate the differences in CD8 epitopes frequencies from the Los Alamos database between groups of patients that showed distinct response to pegylated alpha-INF with ribavirin therapy and test evidence of natural selection on the virus in those who failed treatment, using five maximum likelihood evolutionary models from PAML package. The group of sustained virological responders showed three epitopes with frequencies higher than Non-responders group, all had statistical support, and we observed evidence of selection pressure in the last group. No escape mutation was observed. Interestingly, the epitope VLSDFKTWL was 100% conserved in SVR group. These results suggest that the response to treatment can be explained by the increase in immune pressure, induced by interferon therapy, and the presence of those epitopes may represent an important factor in determining the outcome of therapy.

Araucaria forest dynamics in relation to fire frequency in southern Brazil based on fossil and modern pollen dataf

To elucidate the relationship between forest dynamics and fire frequency pollen percentages and charcoal amounts from a 120 cm long peat core and from samples of modern pollen rain were collected along a transect. The study site in southern Brazil is characterized by a species-rich mosaic of grassland-Araucaria forest. It is of crucial importance for management strategies for conservation to understand the development and maintenance of these vegetation mosaics including their sharp forest-grassland boundaries. During the late Holocene, considerable changes occurred in the area. From Anno Domini (AD) 1360 to 1410, the area was dominated by Campos (grassland) vegetation and fire was very common. From AD 1410 to 1500, Araucaria forest expanded and fire was less frequent. From AD 1500 to 1580, Campos grassland spread and the Araucaria forest ceased its development, apparently due to the increase of fire. From AD 1580 to 1935, after a decrease in fire frequency, Araucaria forest expanded again. From AD 1935 to the present, the Araucaria forest expanded while the Campos area decreased. Fire was very rare in this period. The results indicate a strong interaction of forest expansion, forming a mosaic of Campos and Araucaria forest, and the frequency of fire during the past 600 years. A possible collapse of the indigenous population following the post-Colombian colonization in southern Brazil after about AD 1550 may have caused a great reduction of fire frequency. The introduction of cattle (probably after AD 1780) and the resulting decrease of fire frequency might be the reason for forest expansion. Fire is probably the most important factor controlling the dynamics of the forest-grassland mosaics and the formation of sharp borders between these two vegetation types. (C) 2010 Elsevier B.V. All rights reserved.

The relation between action, predictability and temporal contiguity in temporal binding

Previous studies have documented a subjective temporal attraction between actions and their effects. This finding, named intentional binding, is thought to be the result of a cognitive function that links actions to their consequences. Although several studies have tried to outline the necessary and sufficient conditions for intentional binding, a quantitative comparison between the roles of temporal contiguity, predictability and voluntary action and the evaluation of their interactions is difficult due to the high variability of the temporal binding measurements. In the present study, we used a novel methodology to investigate the properties of intentional binding. Subjects judged whether an auditory stimulus, which could either be triggered by a voluntary finger lift or be presented after a visual temporal marker unrelated to any action, was presented synchronously with a reference stimulus. In three experiments, the predictability, the interval between action and consequence and the presence of action itself were manipulated. The results indicate that (1) action is a necessary condition for temporal binding; (2) a fixed interval between the two events is not sufficient to cause the effect and (3) only in the presence of voluntary action do temporal predictability and contiguity play a significant role in modulating the effect.These findings are discussed in the context of the relationship between intentional binding and temporal expectation. (C) 2010 Elsevier B.V. All rights reserved.

Relation of genetic phylogeny and geographical distance of tick-borne encephalitis virus in central Europe

Tick-borne encephalitis virus (TBEV) is the most important arboviral agent causing disease of the central nervous system in central Europe. In this study, 61 TBEV E gene sequences derived from 48 isolates from the Czech Republic, and four isolates and nine TBEV strains detected in ticks from Germany, covering more than half a century from 1954 to 2009, were sequenced and subjected to phylogenetic and Bayesian phylodynamic analysis to determine the phylogeography of TBEV in central Europe. The general Eurasian continental east-to-west pattern of the spread of TBEV was confirmed at the regional level but is interlaced with spreading that arises because of local geography and anthropogenic influence. This spread is reflected by the disease pattern in the Czech Republic that has been observed since 1991. The overall evolutionary rate was estimated to be approximately 8x10(-4) substitutions per nucleotide per year. The analysis of the TBEV E genes of 11 strains isolated at one natural focus in Zd`ar Kaplice proved for the first time that TBEV is indeed subject to local evolution.

An analytical relation between entropy production and quantum Lyapunov exponents for Gaussian bipartite systems

We study and compare the information loss of a large class of Gaussian bipartite systems. It includes the usual Caldeira-Leggett-type model as well as Anosov models ( parametric oscillators, the inverted oscillator environment, etc), which exhibit instability, one of the most important characteristics of chaotic systems. We establish a rigorous connection between the quantum Lyapunov exponents and coherence loss, and show that in the case of unstable environments coherence loss is completely determined by the upper quantum Lyapunov exponent, a behavior which is more universal than that of the Caldeira-Leggett-type model.

Culture-area relation in Axelrod`s model for culture dissemination

Axelrod`s model for culture dissemination offers a nontrivial answer to the question of why there is cultural diversity given that people`s beliefs have a tendency to become more similar to each other`s as they interact repeatedly. The answer depends on the two control parameters of the model, namely, the number F of cultural features that characterize each agent, and the number q of traits that each feature can take on, as well as on the size A of the territory or, equivalently, on the number of interacting agents. Here, we investigate the dependence of the number C of distinct coexisting cultures on the area A in Axelrod`s model, the culture-area relationship, through extensive Monte Carlo simulations. We find a non-monotonous culture-area relation, for which the number of cultures decreases when the area grows beyond a certain size, provided that q is smaller than a threshold value q (c) = q (c) (F) and F a parts per thousand yen 3. In the limit of infinite area, this threshold value signals the onset of a discontinuous transition between a globalized regime marked by a uniform culture (C = 1), and a completely polarized regime where all C = q (F) possible cultures coexist. Otherwise, the culture-area relation exhibits the typical behavior of the species-area relation, i.e., a monotonically increasing curve the slope of which is steep at first and steadily levels off at some maximum diversity value.

Relation between sedimentary framework and hydrogeology in the Guarani Aquifer System in Sao Paulo state, Brazil

This paper presents the results of a new investigation of the Guarani Aquifer System (SAG) in Sao Paulo state. New data were acquired about sedimentary framework, flow pattern, and hydrogeochemistry. The flow direction in the north of the state is towards the southwest and not towards the west as expected previously. This is linked to the absence of SAG outcrop in the northeast of Sao Paulo state. Both the underlying Piramboia Formation and the overlying Botucatu Formation possess high porosity (18.9% and 19.5%, respectively), which was not modified significantly by diagenetic changes. Investigation of sediments confirmed a zone of chalcedony cement close to the SAG outcrop and a zone of calcite cement in the deep confined zone. The main events in the SAG post-sedimentary history were: (1) adhesion of ferrugineous coatings on grains, (2) infiltration of clays in eodiagenetic stage, (3) regeneration of coatings with formation of smectites, (4) authigenic overgrowth of quartz and K-feldspar in advanced eodiagenetic stage, (5) bitumen cementation of Piramboia Formation in mesodiagenetic stage, (6) cementation by calcite in mesodiagenetic and telodiagenetic stages in Piramboia Formation, (7) formation of secondary porosity by dissolution of unstable minerals after appearance of hydraulic gradient and penetration of the meteoric water caused by the uplift of the Serra do Mar coastal range in the Late Cretaceous, (8) authigenesis of kaolinite and amorphous silica in unconfined zone of the SAG and cation exchange coupled with the dissolution of calcite at the transition between unconfined and confined zone, and (9) authigenesis of analcime in the confined SAG zone. The last two processes are still under operation. The deep zone of the SAG comprises an alkaline pH, Na-HCO(3) groundwater type with old water and enriched delta(13)C values (<-3.9), which evolved from a neutral pH, Ca-HCO(3) groundwater type with young water and depleted delta(13)C values (>-18.8) close to the SAG outcrop. This is consistent with a conceptual geochemical model of the SAG, suggesting dissolution of calcite driven by cation exchange, which occurs at a relatively narrow front recently moving downgradient at much slower rate compared to groundwater flow. More depleted values of delta(18)O in the deep confined zone close to the Parana River compared to values of relative recent recharged water indicate recharge occur during a period of cold climate. The SAG is a ""storage-dominated"" type of aquifer which has to be managed properly to avoid its overexploitation. (C) 2011 Elsevier Ltd. All rights reserved.

Palaeodrainage on Marajo Island, northern Brazil, in relation to Holocene relative sea-level dynamics

A large area in northeastern Marajo Island, northern Brazil, has been characterized geomorphologically, applying information acquired from Landsat imagery. This study was combined with detailed sedimentologic analysis of continuous cores, which provided a record of depositional settings developed in this area through the Holocene. The results revealed well-preserved, meandering to anastomosed drainage networks of wide palaeochannels that were superimposed by a narrower palaeochannel system. In both cases, the sedimentary record consists of sands, heterolithic deposits and muds, locally rich in plant debris. The strata are organized into fining upward successions that reach approximately 18 m thick in the wide channels and 4 m thick in the narrow channels. Sedimentary features suggestive of a coastal location for the wider palaeochannels and reworking of sediments by tidal currents include the prevalence of well to moderately sorted, rounded to sub-rounded, fine- to medium-grained sands displaying foreset packages separated by mud couplets, suggestive of tidal cycles. The data presented herein point to a rise in relative sea level reaching the Lake Arari area during the early to late/mid Holocene. This event was followed by a relative sea level drop. Tectonics seem to have contributed to an overall lowering in relative sea level in the study area since the mid-Holocene, which does not follow the same pattern recorded in other areas along the northern Brazilian coast.

Holocene fires in East Amazonia (Caraja`s), new evidences, chronology and relation with paleoclimate

Past studies have evidenced the presence of charcoal in soils and lacustrine sediments of Amazonia region and suggested occurrences of widespread fires during the Middle Holocene. However, the available records do not indicate the changes in fire regime with enough time resolution. We quantified charcoal fragments in lacustrine sediments in a lake of North Carajas plateau in East Amazonia (5 degrees 50`-6 degrees 35`S and 49 degrees 30`-52 degrees 00`W). The charcoal quantification was compared to other sediment proxies, allowing a connection between paleofires and climate changes. Large variations in sediment characteristics led to distinct stages of sedimentation. From 11,800 (base of CSN 93/4) to 4750 cal yr B.P., low accumulation rates of organic matter are observed. Between 7600 cal yr B.P. (base of CSN 93/3 core) and 4750 cal yr B.P., this initial phase of sedimentation is characterized by low chlorophyll derivate accumulation rates and high accumulation rates of Botryococcus braunii, an alga resistant to episodic drought. The first phase of sedimentation would therefore correspond to, a low take level and a drier climate than today. Large biomass burning events occurred between 7450 cal yr B.P. and 4750 cal yr B.P., as indicated by the high charcoal particle concentration. From 4750 cal yr B.P. to 2800 cal yr B.P., accumulation rates of charcoal particles decreased, and the accumulation rate of chlorophyll derivate was low. From 2800 cal yr B.P. to 1300 cal yr B.P., the charcoal accumulation rates reached their lowest values in the core and a rapid increase in lacustrine production is evidenced by the increase in chlorophyll derivates and carbon accumulation rate. From 1300 cal yr B.P. to the last century, the charcoal accumulation rates increased. During the most recent period, the record is characterized by high accumulation rates of chlorophyll derivates while the charcoal particle accumulation rate decreased. This region is still unaffected by the current increase of anthropogenic fires. (c) 2007 Elsevier B.V. All rights reserved.

A simple relation between the Leimkuhler curve and the mean residual life

In this paper, a simple relation between the Leimkuhler curve and the mean residual life is established. The result is illustrated with several models commonly used in informetrics, such as exponential, Pareto and lognormal. Finally, relationships with some other reliability concepts are also presented. (C) 2010 Elsevier Ltd. All rights reserved.

Characterization of a beta-1,3-glucanase active in the alkaline midgut of Spodoptera frugiperda larvae and its relation to beta-glucan-binding proteins

Spodoptera frugiperda beta-1,3-glucanase (SLam) was purified from larval midgut. It has a molecular mass of 37.5 kDa, an alkaline optimum pH of 9.0, is active against beta-1,3-glucan (laminarin), but cannot hydrolyze yeast beta-1,3-1,6-glucan or other polysaccharides. The enzyme is an endoglucanase with low processivity (0.4), and is not inhibited by high concentrations of substrate. In contrast to other digestive beta-1,3-glucanases from insects, SLam is unable to lyse Saccharomyces cerevisae cells. The cDNA encoding SLam was cloned and sequenced, showing that the protein belongs to glycosyl hydrolase family 16 as other insect glucanases and glucan-binding proteins. Multiple sequence alignment of beta-1,3-glucanases and beta-glucan-binding protein supports the assumption that the beta-1,3-glucanase gene duplicated in the ancestor of mollusks and arthropods. One copy originated the derived beta-1,3-glucanases by the loss of an extended N-terminal region and the beta-glucan-binding proteins by the loss of the catalytic residues. SLam homology modeling suggests that E228 may affect the ionization of the catalytic residues, thus displacing the enzyme pH optimum. SLam antiserum reacts with a single protein in the insect midgut. Immunocytolocalization shows that the enzyme is present in secretory vesicles and glycocalyx from columnar cells. (C) 2010 Elsevier Ltd. All rights reserved.

Kvinnors erfarenheter av amningstidens längd i relation till vårdtidens längd : En retrospektiv studie

Syftet med denna studie var att undersöka nyblivna mödrars uppfattning av amningstidens längd och vårdtidens längd relaterat till bakgrundsvariablerna ålder, utbildning och paritet. Datainsamlingen skedde under hösten 2000 och våren 2001. Insamlat material infördes i det statistiska programmet Stat View. Materialet bearbetades därefter i olika statistiska test som t-test, korrelations test och Chi-två test. Resultatet för den exklusiva amningen visar att kvinnor som är högutbildade och omföderskor ammar längre än de lågutbildade och förstföderskor. Den totala amningstiden påverkas av moderns ålder och utbildning. Av de 250 informanterna som deltog i studien uppger endast 53 procent att de är nöjda med amningen. Det framkommer också att förstföderskor och ju äldre kvinnan är desto längre stannar hon på BB. Utbildningsnivån har däremot ingen inverkan på hur länge kvinnorna är kvar på BB. Det mest anmärkningsvärda är att det inte finns något samband mellan vårdtidens längd och amningstidens längd då flera äldre och färskare studier från Sverige, USA och Australien har påpekat att ett sådant samband existerar.

Pojkar spelar fotboll och flickor hoppar hage : En undersökning av kön och genus och dess relation till skolan

Uppsatsens första syfte är att utreda begreppen kön och genus. Vad kan dessa omdebatterade begrepp ha för olika betydelse? Uppsatsen andra syfte är att, med hjälp av en liten studie, ge exempel på hur en undersökning av kön och genus i skolan kan se ut. Studien tar sin utgångspunkt i På lika villkor, ett jämställdhetsprojekt som startade i Falu kommun 1994. Påverkar lärarens deltagande i projektet elevernas sätt att vara i förhållande till genus? Svaret blir både nej och ja.