Recent benthic foraminiferal distribution and related environmental factors in Ezcurra Inlet, King George Island, Antarctica

This investigation attempts to determine which environmental parameters of the bottom water and sediment control recent foraminifera fauna at Ezcurra Inlet (King George Island, Antarctica), using data collected during four summers (2002/03, 2003/04, 2004/05 and 2006/07). The study revealed that Ezcurra Inlet contain typical Antarctic foraminifera fauna with three distinct assemblages and few differences in environmental parameters. The species Bolivina pseudopunctata, Fursenkoina fusiformis, Portatrochammina antarctica, and Adercotryma glomerata were abundant in the samples. An elevated abundance, richness and diversity were common at the entrance of the inlet at depths greater than 55 m, where the inlet was characterized by low temperatures and muddy sand. In the inner part of the inlet (depth 30-55 m), richness and diversity were low and the most significant species were Cassidulinoides parkerianus, C. porrectus, and Psammosphaera fusca. Shallow waters showed low values of richness and abundance and high temperatures coupled with coarser sediment. In areas with high suspended matter concentrations and pH values associated with low salinity the most representative species were Hippocrepinella hirudinea and Hemisphaerammina bradyi.

Microfacies and sequence stratigraphy of the Amapa Formation, Late Paleocene to Early Eocene, Foz do Amazonas Basin, Brazil

On the basis of thin-section studies of cuttings and a core from two wells in the Amapa Formation of the Foz do Amazonas Basin, five main microfacies have been recognized within three stratigraphic sequences deposited during the Late Paleocene to Early Eocene. The facies are: 1) Ranikothalia grainstone to packstone facies; 2) ooidal grainstone to packstone facies; 3) larger foraminiferal and red algal grainstone to packstone facies; 4) Amphistegina and Helicostegina packstone facies; and 5) green algal and small benthic foraminiferal grainstone to packstone facies, divisible locally into a green algal and the miliolid foraminiferal subfacies and a green algal and small rotaliine foraminiferal subfacies. The lowermost sequence (Si) was deposited in the Late Paleocene-Early Eocene (biozone LF1, equivalent to P3-P6?) and includes rudaceous grainstones and packstones with large specimens of Ranikothalia bermudezi representative of the mid- and inner ramp. The intermediate and uppermost sequences (S2 and S3) display well-developed lowstand deposits formed at the end of the Late Paleocene (upper biozone LF1) and beginning of the Early Eocene (biozone LF2) on the inner ramp (larger foraminiferal and red algal grainstone to packstone facies), in lagoons (green algal and small benthic foraminiferal facies) and as shoals (ooidal facies) or banks (Amphistegina and Helicostegina facies). Depth and oceanic influence were the main controls on the distribution of these microfacies. Stratal stacking patterns evident within these sequences may well have been related to sea level changes postulated for the Late Paleocene and Early Eocene. During this time, the Amapa Formation was dominated by cyclic sedimentation on a gently sloping ramp. Environmental and ecological stress brought about by sea level change at the end of the biozone LF1 led to the extinction of the larger foraminifera (Ranikothalia bermudezi). (c) 2009 Elsevier B.V. All rights reserved.

ICHTHYOPLANKTON DISTRIBUTION AND ABUNDANCE IN THE NORTHERN TODOS OS SANTOS AND CAMAMU BAYS, BAHIA STATE - BRAZIL

The occurrence, distribution and abundance of ichthyoplankton in Todos os Santos and Camamu Bays were analyzed based on four samplings (winter 2003, summer 2003, winter 2004 and summer 2005). Samples were obtained by surface horizontal hauls, using a 200-mu m mesh conical-cylinder plankton net. The distribution and abundance of eggs indicate a remarkable seasonal and annual variation of spawning activity in the region, especially when the two summer campaigns are compared. In summer 2003 the highest quantitative values were recorded, especially for Camamu, where the maximum reached 106.56 eggs.m(-3), with an overall average of 43.46 eggs.m(-3) for the two areas. In summer 2005 values were relatively low, the overall average being 3.49 eggs.m(-3). The larval taxonomic composition is characterized by the predominance of gobiids, with small variation from summer to winter. Considering all the campaigns and samplings undertaken in both areas, larvae of 11 families were identified: Engraulidae, Clupeidae, Mugilidae, Atherinopsidae, Hemiramphidae, Syngnathidae, Blenniidae, Carangidae, Gobiidae, Achiridae and Tetraodontidae.

Accurate ab initio potential energy surfaces for the (3)A '' and (3)A ' electronic states of the O(P-3) plus HBr system

In this work, we report the construction of potential energy surfaces for the (3)A '' and (3)A' states of the system O(P-3) + HBr. These surfaces are based on extensive ab initio calculations employing the MRCI+Q/CBS+SO level of theory. The complete basis set energies were estimated from extrapolation of MRCI+Q/aug-cc-VnZ(-PP) (n = Q, 5) results and corrections due to spin-orbit effects obtained at the CASSCF/aug-cc-pVTZ(-PP) level of theory. These energies, calculated over a region of the configuration space relevant to the study of the reaction O(P-3) + HBr -> OH + Br, were used to generate functions based on the many-body expansion. The three-body potentials were interpolated using the reproducing kernel Hilbert space method. The resulting surface for the (3)A '' electronic state contains van der Waals minima on the entrance and exit channels and a transition state 6.55 kcal/mol higher than the reactants. This barrier height was then scaled to reproduce the value of 5.01 kcal/mol, which was estimated from coupled cluster benchmark calculations performed to include high-order and core-valence correlation, as well as scalar relativistic effects. The (3)A' surface was also scaled, based on the fact that in the collinear saddle point geometry these two electronic states are degenerate. The vibrationally adiabatic barrier heights are 3.44 kcal/mol for the (3)A '' and 4.16 kcal/mol for the (3)A' state. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4705428]

Reproductive migration and population dynamics of the blue crab Callinectes danae in an estuary in southeastern Brazil

Portunid crabs are an important resource in estuaries, and require appropriate management to guarantee their long-term availability. We investigated the population dynamics and reproduction of Callinectes danae in the Estuarine-Bay Complex of Sao Vicente, Sao Paulo, Brazil, to provide basic biological information for public policies for the management of this fishery. Monthly samples were obtained from March 2007 to February 2008 on eight transects, four in the estuary and four in the bay. A total of 2261 specimens (403 males, 1288 females, of which 570 were ovigerous) were collected. Males were significantly larger than females, and the size-frequency distribution was unimodal for males, females and ovigerous females. The sex ratio was nearly always skewed toward females (M:F - 1:4.6). C. danae showed seasonal-continuous reproduction, with high reproductive activity in the warmer season. C. danae breeds in the estuarine-bay complex, with males and juvenile females concentrated in the estuary. After copulation, fertilized females migrate to the estuary entrance and the bay, where ovigerous females are commonly found spawning in high-salinity areas. Therefore, to manage this important economic resource, both the estuary and the bay should be considered for protection, but special attention should be given to the estuary entrance during the summer months, when ovigerous females concentrate.

Is the domestic dog becoming an abundant species in the Atlantic forest? A study case in southeastern Brazil

The Brazilian Atlantic forest has been reduced to a small fraction of its original area, with most remaining fragments being small and surrounded by anthropogenic matrices. This degree of disturbance, together with the increasing sprawl of cities towards the rural zone, greatly facilitates the entrance of domestic animals into these remnants. We used camera traps to compare the abundances of the domestic dog with a similarly sized native carnivore, the ocelot, in a 957-ha reserve of the Brazilian Atlantic forest in a landscape largely composed by pastures and agriculture. The dog was the most recorded species among all 17 mammal species "captured" by the cameras. Dog abundance (32-38 dogs) and density (0.812-1.813 dogs/km(2)) were significantly higher than that of the ocelot (n=2 ocelots; density=0.158-0.347 ocelots/km(2)). Although our result is restricted to a single study site, it is supported by an increasing number of recent studies, which have detected dogs inside other Atlantic forest reserves. Our study suggests, therefore, that this invasion might be more widespread than generally thought. The presence of the domestic dog is a threat to native fauna and constitutes an important edge effect of human presence at the rural zone.

Redox Control of 20S Proteasome Gating

The proteasome is the primary contributor in intracellular proteolysis. Oxidized or unstructured proteins can be degraded via a ubiquitin-and ATP-independent process by the free 20S proteasome (20SPT). The mechanism by which these proteins enter the catalytic chamber is not understood thus far, although the 20SPT gating conformation is considered to be an important barrier to allowing proteins free entrance. We have previously shown that S-glutathiolation of the 20SPT is a post-translational modification affecting the proteasomal activities. Aims: The goal of this work was to investigate the mechanism that regulates 20SPT activity, which includes the identification of the Cys residues prone to S-glutathiolation. Results: Modulation of 20SPT activity by proteasome gating is at least partially due to the S-glutathiolation of specific Cys residues. The gate was open when the 20SPT was S-glutathiolated, whereas following treatment with high concentrations of dithiothreitol, the gate was closed. S-glutathiolated 20SPT was more effective at degrading both oxidized and partially unfolded proteins than its reduced form. Only 2 out of 28 Cys were observed to be S-glutathiolated in the proteasomal alpha 5 subunit of yeast cells grown to the stationary phase in glucose-containing medium. Innovation: We demonstrate a redox post-translational regulatory mechanism controlling 20SPT activity. Conclusion: S-glutathiolation is a post-translational modification that triggers gate opening and thereby activates the proteolytic activities of free 20SPT. This process appears to be an important regulatory mechanism to intensify the removal of oxidized or unstructured proteins in stressful situations by a process independent of ubiquitination and ATP consumption. Antioxid. Redox Signal. 16, 1183-1194.

Disentangling social networks from spatiotemporal dynamics: the temporal structure of a dolphin society

Social networks are static illustrations of dynamic societies, within which social interactions are constantly changing. Fundamental sources of variation include ranging behaviour and temporal demographic changes. Spatiotemporal dynamics can favour or limit opportunities for individuals to interact, and then a network may not essentially represent social processes. We examined whether a social network can embed such nonsocial effects in its topology, whereby emerging modules depict spatially or temporally segregated individuals. To this end, we applied a combination of spatial, temporal and demographic analyses to a long-term study of the association patterns of Guiana dolphins, Sotalia guianensis. We found that association patterns are organized into a modular social network. Space use was unlikely to reflect these modules, since dolphins' ranging behaviour clearly overlapped. However, a temporal demographic turnover, caused by the exit/entrance of individuals (most likely emigration/immigration), defined three modules of associations occurring at different times. Although this factor could mask real social processes, we identified the temporal scale that allowed us to account for these demographic effects. By looking within this turnover period (32 months), we assessed fission-fusion dynamics of the poorly known social organization of Guiana dolphins. We highlight that spatiotemporal dynamics can strongly influence the structure of social networks. Our findings show that hypothetical social units can emerge due to the temporal opportunities for individuals to interact. Therefore, a thorough search for a satisfactory spatiotemporal scale that removes such nonsocial noise is critical when analysing a social system. (C) 2012 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

Private and Public Dental Care in the City of Sao Paulo in the First Decade of the XXI Century

Two concomitant movements occur in the first decade of the XXI century within the private and public dental services in Brazil: the entrance of oral health on the agenda of political priorities of the federal government and the vigorous growth of additional dental care. We analyzed the occurrence of these phenomena in the city of Sao Paulo, by seeking information in official documents and electronic databases in the Municipality of Sao Paulo, the Ministry of Health and National Health Agency (ANS), and also in scientific literature. During the studied period - January 2000 to December 2009 - and with basis on indicators such as coverage of First Consultation Program and Dental coverage Population Potential, percentages were found that characterize low public assistance and a situation far short of the constitutional principle of universal access to dental care. The growing number of beneficiaries of additional services through exclusively dental coverage insurance plans and other types of private insurance plans in the same period was significant, accounting for a major expansion of population coverage in this mode of care. It was found that, compared to the overall national framework, the city of Sao Paulo offers poor access to public dental care, with reduced supply of services to adults and aged people. Furthermore, considering the limitations of market additional services to provide dental care to all Brazilians, it reinforces the need for continuity and expansion of Brasil Sorridente, which is the programmatic expression of the National Oral Health Politics.

The Nuss procedure made safer: an effective and simple sternal elevation manoeuvre

The Nuss procedure requires the creation of a substernal tunnel for bar positioning. This is a manoeuvre that can be dangerous, and cardiac perforation has occurred in a few cases. Our purpose was to describe two technical modifications that enable the prevention of these fatal complications. A series of 25 patients with pectus excavatum were treated with a modification of the Nuss procedure that included the entrance in the left haemithorax first, and the use of the retractor to lift the sternum, with the consequent lowering displacement of the heart. These modified techniques have certain advantages: (i) the narrow anterior mediastinum between the sternum and the pericardial sac is expanded by pulling up the sternum; (ii) the thoracoscopic visualization of the tip of the introducer during tunnel creation is improved; (iii) the rubbing of the introducer against the pericardium is minimized; (iv) the exit path of the introducer can be guided by the surgeon's finger and (v) haemostasis and integrity of the pericardial sac can be more easily confirmed. We observed that with these manoeuvres, the risk of pericardial sac and cardiac injury can be markedly reduced.

Modeling the Emergence of Circadian Rhythms in a Clock Neuron Network

Circadian rhythms in pacemaker cells persist for weeks in constant darkness, while in other types of cells the molecular oscillations that underlie circadian rhythms damp rapidly under the same conditions. Although much progress has been made in understanding the biochemical and cellular basis of circadian rhythms, the mechanisms leading to damped or self-sustained oscillations remain largely unknown. There exist many mathematical models that reproduce the circadian rhythms in the case of a single cell of the Drosophila fly. However, not much is known about the mechanisms leading to coherent circadian oscillation in clock neuron networks. In this work we have implemented a model for a network of interacting clock neurons to describe the emergence (or damping) of circadian rhythms in Drosophila fly, in the absence of zeitgebers. Our model consists of an array of pacemakers that interact through the modulation of some parameters by a network feedback. The individual pacemakers are described by a well-known biochemical model for circadian oscillation, to which we have added degradation of PER protein by light and multiplicative noise. The network feedback is the PER protein level averaged over the whole network. In particular, we have investigated the effect of modulation of the parameters associated with (i) the control of net entrance of PER into the nucleus and (ii) the non-photic degradation of PER. Our results indicate that the modulation of PER entrance into the nucleus allows the synchronization of clock neurons, leading to coherent circadian oscillations under constant dark condition. On the other hand, the modulation of non-photic degradation cannot reset the phases of individual clocks subjected to intrinsic biochemical noise.

Lithium in M 67: From the main sequence to the red giant branch

Context. Lithium abundances in open clusters are a very effective probe of mixing processes, and their study can help us to understand the large depletion of lithium that occurs in the Sun. Owing to its age and metallicity, the open cluster M 67 is especially interesting on this respect. Many studies of lithium abundances in M 67 have been performed, but a homogeneous global analysis of lithium in stars from subsolar masses and extending to the most massive members, has yet to be accomplished for a large sample based on high-quality spectra. Aims. We test our non-standard models, which were calibrated using the Sun with observational data. Methods. We collect literature data to analyze, for the first time in a homogeneous way, the non-local thermal equilibrium lithium abundances of all observed single stars in M 67 more massive than similar to 0.9 M-circle dot. Our grid of evolutionary models is computed assuming a non-standard mixing at metallicity [Fe/H] = 0.01, using the Toulouse-Geneva evolution code. Our analysis starts from the entrance into the zero-age main-sequence. Results. Lithium in M 67 is a tight function of mass for stars more massive than the Sun, apart from a few outliers. A plateau in lithium abundances is observed for turn-off stars. Both less massive (M >= 1.10 M-circle dot) and more massive (M >= 1.28 M-circle dot) stars are more depleted than those in the plateau. There is a significant scatter in lithium abundances for any given mass M <= 1.1 M-circle dot. Conclusions. Our models qualitatively reproduce most of the features described above, although the predicted depletion of lithium is 0.45 dex smaller than observed for masses in the plateau region, i.e. between 1.1 and 1.28 solar masses. More work is clearly needed to accurately reproduce the observations. Despite hints that chromospheric activity and rotation play a role in lithium depletion, no firm conclusion can be drawn with the presently available data.

The role of wax and resin in the nestmate recognition system of a stingless bee, Tetragonisca angustula

Recent research has shown that entrance guards of the stingless bee Tetragonisca angustula make less errors in distinguishing nestmates from non-nestmates than all other bee species studied to date, but how they achieve this is unknown. We performed four experiments to investigate nestmate recognition by entrance guards in T. angustula. We first investigated the effect of colony odours on acceptance. Nestmates that acquired odour from non-nestmate workers were 63% more likely to be rejected while the acceptance rate of non-nestmates treated with nestmate odour increased by only 7%. We further hypothesised that guards standing on the wax entrance tube might use the tube as an odour referent. However, our findings showed that there was no difference in the acceptance of non-nestmates by guards standing on their own colony's entrance tube versus the non-nestmate's entrance tube. Moreover, treatment of bees with nestmate and non-nestmate resin or wax had a negative effect on acceptance rates of up to 65%, regardless of the origin of the wax or resin. The role of resin as a source of recognition cues was further investigated by unidirectionally transferring resin stores between colonies. Acceptance rates of nestmates declined by 37% for hives that donated resin, contrasting with resin donor hives where acceptance of non-nestmates increased by 21%. Overall, our results confirm the accuracy of nestmate recognition in T. angustula and reject the hypothesis that this high level of accuracy is due to the use of the wax entrance tubes as a referent for colony odour. Our findings also suggest that odours directly acquired from resin serve no primary function as nestmate recognition cues. The lack of consistency among colonies plus the complex results of the third and fourth experiments highlight the need for further research on the role of nest materials and cuticular profiles in understanding nestmate recognition in T. angustula.

Limitations of Neoseiulus baraki and Proctolaelaps bickleyi as control agents of Aceria guerreronis

Several predatory mites have been found in association with the coconut mite, Aceria guerreronis Keifer, in northeast Brazil. However, the latter still causes damage to coconut in that region. The objectives of this work were to compare the frequencies of occurrence of Neoseiulus (Phytoseiidae) and Proctolaelaps (Melicharidae) species on standing and aborted coconuts in coastal Pernambuco State, northeast Brazil and to analyze their possible limitations as control agents of the coconut mite, based on evaluations of the restrictions they may have to access the microhabitat inhabited by the pest and their functional and reproductive responses to increasing densities of the latter. Neoseiulus baraki (Athias-Henriot) was found mostly on standing coconuts whereas Proctolaelaps bickleyi (Bram) was found mostly on aborted coconuts. Measurements of the entrance to the microhabitat occupied by the coconut mite, between the bracts and the subjacent fruit surface, showed that this different pattern of predator prevalence could be related to predator sizes, although other environmental factors could not be disregarded. Progressively higher predation rate of N. baraki was observed up to an experimental density that corresponded to 1,200 coconut mites per fruit, which is close to the average number determined in northeast Brazil, reducing slightly afterwards. Predation rate of P. bickleyi reduced consistently but slightly with increasing prey densities, but in absolute values, rates were always much higher than determined for N. baraki. The excessively high killing capacity of P. bickleyi, probably related to its high feeding requirement, may be detrimental in terms of stability. In fact, such high requirement for food suggests that P. bickleyi might not have a strong relation with the coconut mite and that the latter may not be its main food source under natural conditions. It is concluded that body sizes of both predators and the exceedingly high feeding requirement of P. bickleyi may limit their performance as control agents of the coconut mite.

A morphologically specialized soldier caste improves colony defense in a neotropical eusocial bee

Division of labor among workers is common in insect societies and is thought to be important in their ecological success. In most species, division of labor is based on age (temporal castes), but workers in some ants and termites show morphological specialization for particular tasks (physical castes). Large-headed soldier ants and termites are well-known examples of this specialization. However, until now there has been no equivalent example of physical worker subcastes in social bees or wasps. Here we provide evidence for a physical soldier subcaste in a bee. In the neotropical stingless bee Tetragonisca angustula, nest defense is performed by two groups of guards, one hovering near the nest entrance and the other standing on the wax entrance tube. We show that both types of guards are 30% heavier than foragers and of different shape; foragers have relatively larger heads, whereas guards have larger legs. Low variation within each subcaste results in negligible size overlap between guards and foragers, further indicating that they are distinct physical castes. In addition, workers that remove garbage from the nest are of intermediate size, suggesting that they might represent another unrecognized caste. Guards or soldiers are reared in low but sufficient numbers (1-2% of emerging workers), considering that <1% usually perform this task. When challenged by the obligate robber bee Lestrimelitta limao, an important natural enemy, larger workers were able to fight for longer before being defeated by the much larger robber. This discovery opens up opportunities for the comparative study of physical castes in social insects, including the question of why soldiers appear to be so much rarer in bees than in ants or termites.