Reproductive strategy of a non-annual rivulid in a perennial wetland

ABSTRACT Atlantirivulus riograndensis (Costa & Lanés, 2009) is a fish registered to the basin of Patos lagoon and the adjacent coastal plains in southern states of Rio Grande do Sul and Santa Catarina, Brazil, found in shallow water courses with that have large quantities of aquatic vegetation and forest edges. The objective of this study was to investigate the reproductive strategy and tactics of this species including the sex ratio, the length at first maturity, spawning type, fecundity and the possible associations among reproduction and abiotic factors. Sampling of specimens occurred in perennial wetlands within the Banhado dos Pachecos wildlife refuge, in the city of Viamão, state of Rio Grande do Sul, Brazil, which is a conservation unit that belongs to an area of environmental protection in the Pampa Biome. The capture of 30 A. riograndensis specimens per month occurred from January to December of 2012. A total of 188 females and 172 males were captured and the total sex ratio was 1:1 in the sampled population. Sexual maturity of the species occurs after 13.59 and 11.92 mm (SL) for females and males, respectively. Both a multiple spawning and a long reproductive period (since August to March) were confirmed by the presence of post-ovulatory follicles that were observed through histological analysis and the values of the gonadosomatic index in females considered spawning capable. The average absolute fecundity of the species is of 19.33 (± 6.18) vitellogenic oocytes in mature ovaries. No significant relationship was found between mean GSI and the abiotic data. Reproductive tactics presented by A. riograndensis indicate a species with an opportunistic reproductive strategy, following the pattern of other species of the Rivulidae family.

Bidding at sequential first-price auctions with(out) supply uncertainty: a laboratory analysis

We report on a series of experiments that test the effects of an uncertain supply on the formation of bids and prices in sequential first-price auctions with private-independent values and unit-demands. Supply is assumed uncertain when buyers do not know the exact number of units to be sold (i.e., the length of the sequence). Although we observe a non-monotone behavior when supply is certain and an important overbidding, the data qualitatively support our price trend predictions and the risk neutral Nash equilibrium model of bidding for the last stage of a sequence, whether supply is certain or not. Our study shows that behavior in these markets changes significantly with the presence of an uncertain supply, and that it can be explained by assuming that bidders formulate pessimistic beliefs about the occurrence of another stage.

Observations on two biological races of Schistosoma mansoni

A comparative study of the BH strain of Schistosoma mansoni from Belo Horizonte, Minas Gerais state, infective to Biomphalaria glabrata from the same locality, and the SJ strain from São José dos Campos, São Paulo state, infective to B. tenagophila from the latter locality, showed the following differences: 1. Length of adult worms and size of eggs significantly larger in the BH strain. 2. Higher infection rates in the B. glabrata-BH strain association than in the B. tenagophila-SJ strain association, following exposure of each snail to 1 or 10 miracidia. 3.Longer prepatent period (from penetration of miracidium to first shedding of cercariae) in the B. tenagophila-SJ strain association. 4. Infection of both Biomphalaria species when exposed to hybrid miracidia from crosses between the two strains, at lower levels than those resulting from exposure of each snail species to miracidia of the pure sympatric strain. (Both Biomphalaria populations are practically refractory to infection with the allopatric strain). These results are interpreted as pointing to a better host-parasite adjustment in the B. glabrata-BH strain association than in the B. tenagophila-SJ association. The interfertility between the two strains, which produced viable hybrids infective to both Biomphalaria species, supports the conclusion that the observed differences are merely intraspecific, and that the two strains may be considered distinct biological races of Schistosoma mansoni.

Features of reproduction in laboratory-reared Aedes fluviatilis (Lutz, 1904) (Diptera: Culicidae)

Observations were made on 100 female Aedes fluviatilis (Lutz) maintained individually from the first blood meal onwards and allowed one blood meal during each oviposition cycle, 5% dextrose solution been supplied throughout life. The average length of live was 49.9 ± 17.8 days; the logarithm of the mortality rate increased proportionately to physiological age. The insects took an average of 7.3 ± 3.2 blood meals and produced a mean of 7.9 ± 3.7 clutches of eggs. There was a progressive decrease, proportional to advancing physiological age, in the mean numbers of eggs laid in successive oviposition cycles, in the intervals between blood feeding oviposition, and in the numbers of larvae that hatched. Delayed oviposition, transient sterility and a total loss of fertility were also recorded.

On the complexity of the Whitehead minimization problem

The Whitehead minimization problem consists in finding a minimum size element in the automorphic orbit of a word, a cyclic word or a finitely generated subgroup in a finite rank free group. We give the first fully polynomial algorithm to solve this problem, that is, an algorithm that is polynomial both in the length of the input word and in the rank of the free group. Earlier algorithms had an exponential dependency in the rank of the free group. It follows that the primitivity problem – to decide whether a word is an element of some basis of the free group – and the free factor problem can also be solved in polynomial time.

Surviving Sepsis Campaign: international guidelines for management of severe sepsis and septic shock: 2008.

OBJECTIVE: To provide an update to the original Surviving Sepsis Campaign clinical management guidelines, "Surviving Sepsis Campaign Guidelines for Management of Severe Sepsis and Septic Shock," published in 2004. DESIGN: Modified Delphi method with a consensus conference of 55 international experts, several subsequent meetings of subgroups and key individuals, teleconferences, and electronic-based discussion among subgroups and among the entire committee. This process was conducted independently of any industry funding. METHODS: We used the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) system to guide assessment of quality of evidence from high (A) to very low (D) and to determine the strength of recommendations. A strong recommendation (1) indicates that an intervention's desirable effects clearly outweigh its undesirable effects (risk, burden, cost) or clearly do not. Weak recommendations (2) indicate that the tradeoff between desirable and undesirable effects is less clear. The grade of strong or weak is considered of greater clinical importance than a difference in letter level of quality of evidence. In areas without complete agreement, a formal process of resolution was developed and applied. Recommendations are grouped into those directly targeting severe sepsis, recommendations targeting general care of the critically ill patient that are considered high priority in severe sepsis, and pediatric considerations. RESULTS: Key recommendations, listed by category, include early goal-directed resuscitation of the septic patient during the first 6 hrs after recognition (1C); blood cultures before antibiotic therapy (1C); imaging studies performed promptly to confirm potential source of infection (1C); administration of broad-spectrum antibiotic therapy within 1 hr of diagnosis of septic shock (1B) and severe sepsis without septic shock (1D); reassessment of antibiotic therapy with microbiology and clinical data to narrow coverage, when appropriate (1C); a usual 7-10 days of antibiotic therapy guided by clinical response (1D); source control with attention to the balance of risks and benefits of the chosen method (1C); administration of either crystalloid or colloid fluid resuscitation (1B); fluid challenge to restore mean circulating filling pressure (1C); reduction in rate of fluid administration with rising filing pressures and no improvement in tissue perfusion (1D); vasopressor preference for norepinephrine or dopamine to maintain an initial target of mean arterial pressure > or = 65 mm Hg (1C); dobutamine inotropic therapy when cardiac output remains low despite fluid resuscitation and combined inotropic/vasopressor therapy (1C); stress-dose steroid therapy given only in septic shock after blood pressure is identified to be poorly responsive to fluid and vasopressor therapy (2C); recombinant activated protein C in patients with severe sepsis and clinical assessment of high risk for death (2B except 2C for postoperative patients). In the absence of tissue hypoperfusion, coronary artery disease, or acute hemorrhage, target a hemoglobin of 7-9 g/dL (1B); a low tidal volume (1B) and limitation of inspiratory plateau pressure strategy (1C) for acute lung injury (ALI)/acute respiratory distress syndrome (ARDS); application of at least a minimal amount of positive end-expiratory pressure in acute lung injury (1C); head of bed elevation in mechanically ventilated patients unless contraindicated (1B); avoiding routine use of pulmonary artery catheters in ALI/ARDS (1A); to decrease days of mechanical ventilation and ICU length of stay, a conservative fluid strategy for patients with established ALI/ARDS who are not in shock (1C); protocols for weaning and sedation/analgesia (1B); using either intermittent bolus sedation or continuous infusion sedation with daily interruptions or lightening (1B); avoidance of neuromuscular blockers, if at all possible (1B); institution of glycemic control (1B), targeting a blood glucose < 150 mg/dL after initial stabilization (2C); equivalency of continuous veno-veno hemofiltration or intermittent hemodialysis (2B); prophylaxis for deep vein thrombosis (1A); use of stress ulcer prophylaxis to prevent upper gastrointestinal bleeding using H2 blockers (1A) or proton pump inhibitors (1B); and consideration of limitation of support where appropriate (1D). Recommendations specific to pediatric severe sepsis include greater use of physical examination therapeutic end points (2C); dopamine as the first drug of choice for hypotension (2C); steroids only in children with suspected or proven adrenal insufficiency (2C); and a recommendation against the use of recombinant activated protein C in children (1B). CONCLUSIONS: There was strong agreement among a large cohort of international experts regarding many level 1 recommendations for the best current care of patients with severe sepsis. Evidenced-based recommendations regarding the acute management of sepsis and septic shock are the first step toward improved outcomes for this important group of critically ill patients.

Reproducibility of free-breathing cardiovascular magnetic resonance coronary angiography.

OBJECTIVE: Contemporary free-breathing non contrast enhanced cardiovascular magnetic resonance angiography (CMRA) was qualitatively and quantitatively evaluated to ascertain the reproducibility of the method for coronary artery luminal dimension measurements. SUBJECTS AND METHODS: Twenty-two healthy volunteers (mean age 32 +/- 7 years, 12 males) without coronary artery disease were imaged at 2 centers (1 each in Europe and North America) using navigator-gated and corrected SSFP CMRA on a commercial whole body 1.5T System. Repeat images of right (RCA, n = 21), left anterior descending (LAD, n = 14) and left circumflex (LCX, n = 14) coronary arteries were obtained in separate sessions using identical scan protocol and imaging parameters. True visible vessel length, signal-to-noise (SNR), contrast-to-noise ratios (CNR) and the average luminal diameter over the first 4 cm of the vessel were measured. Intra-observer, inter-observer and inter-scan reproducibility of coronary artery luminal diameter were determined using Pearson's correlation, Bland-Altman analysis and intraclass correlation coefficients (ICC). RESULTS: CNR, SNR and the mean length of the RCA, LAD and LCX imaged for original and repeat scans were not significantly different (all p > 0.30). There was a high degree of intra-observer, inter-observer and inter-scan agreements for RCA, LAD and LCX luminal diameter respectively on Bland-Altman and ICC analysis (ICC's for RCA: 0.98. 0.98 and 0.86; LAD: 0.89, 0.89 and 0.63; LCX: 0.95, 0.94 and 0.79). CONCLUSION: In a 2-center study, we demonstrate that free-breathing 3D SSFP CMRA can visualize long continuous segments of coronary vessels with highly reproducible measurements of luminal diameter.

The relationship between subjective experiences during first use of tobacco and cannabis and the effect of the substance experienced first.

INTRODUCTION: We examined the positive and negative subjective feelings associated with initial tobacco and cannabis use as well as the role of these experiences in regular use. Additionally, we investigated the effect of the first substance experienced on initial subjective experiences and later regular use. METHODS: Baseline data from a representative sample of young Swiss men were obtained from an ongoing Cohort Study on Substance Use Risk Factors, which includes 2,321 lifetime tobacco and cannabis users. We assessed the age of first tobacco and cannabis use along with the subjective experiences associated with initial use. Additionally, subjective experiences related to regular use of both substances were analyzed. RESULTS: The initial subjective experiences were divided into positive and negative for each substance, and we found that the feelings associated with first use of tobacco and cannabis were similar. Moreover, the participants who used cannabis before tobacco reported fewer negative experiences associated with first tobacco use, whereas the participants who initially used tobacco reported more negative experiences related to first cannabis use. Also, we identified that regular use was encouraged by positive experiences and that negative experiences were more adverse for regular use of cannabis compared with tobacco. CONCLUSIONS: Taken together, these results indicate that similar subjective experiences were associated with the first use of tobacco and cannabis. Also, the use of cannabis before tobacco, which occurred in only a minority of users, had the potential to enhance the effects of initial tobacco use.

Visualisation of human rad52 protein and its complexes with hRad51 and DNA.

The human Rad52 protein stimulates joint molecule formation by hRad51, a homologue of Escherichia coli RecA protein. Electron microscopic analysis of hRad52 shows that it self-associates to form ring structures with a diameter of approximately 10 nm. Each ring contains a hole at its centre. hRad52 binds to single and double-stranded DNA. In the ssDNA-hRad52 complexes, hRad52 was distributed along the length of the DNA, which exhibited a characteristic "beads on a string" appearance. At higher concentrations of hRad52, "super-rings" (approximately 30 nm) were observed and the ssDNA was collapsed upon itself. In contrast, in dsDNA-hRad52 complexes, some regions of the DNA remained protein-free while others, containing hRad52, interacted to form large protein-DNA networks. Saturating concentrations of hRad51 displaced hRad52 from ssDNA, whereas dsDNA-Rad52 complexes (networks) were more resistant to hRad51 invasion and nucleoprotein filament formation. When Rad52-Rad51-DNA complexes were probed with gold-conjugated hRad52 antibodies, the presence of globular hRad52 structures within the Rad51 nucleoprotein filament was observed. These data provide the first direct visualisation of protein-DNA complexes formed by the human Rad51 and Rad52 recombination/repair proteins.

Low-frequency drug-resistant HIV-1 and risk of virological failure to first-line NNRTI-based ART: a multicohort European case-control study using centralized ultrasensitive 454 pyrosequencing.

OBJECTIVES: It is still debated if pre-existing minority drug-resistant HIV-1 variants (MVs) affect the virological outcomes of first-line NNRTI-containing ART. METHODS: This Europe-wide case-control study included ART-naive subjects infected with drug-susceptible HIV-1 as revealed by population sequencing, who achieved virological suppression on first-line ART including one NNRTI. Cases experienced virological failure and controls were subjects from the same cohort whose viraemia remained suppressed at a matched time since initiation of ART. Blinded, centralized 454 pyrosequencing with parallel bioinformatic analysis in two laboratories was used to identify MVs in the 1%-25% frequency range. ORs of virological failure according to MV detection were estimated by logistic regression. RESULTS: Two hundred and sixty samples (76 cases and 184 controls), mostly subtype B (73.5%), were used for the analysis. Identical MVs were detected in the two laboratories. 31.6% of cases and 16.8% of controls harboured pre-existing MVs. Detection of at least one MV versus no MVs was associated with an increased risk of virological failure (OR = 2.75, 95% CI = 1.35-5.60, P = 0.005); similar associations were observed for at least one MV versus no NRTI MVs (OR = 2.27, 95% CI = 0.76-6.77, P = 0.140) and at least one MV versus no NNRTI MVs (OR = 2.41, 95% CI = 1.12-5.18, P = 0.024). A dose-effect relationship between virological failure and mutational load was found. CONCLUSIONS: Pre-existing MVs more than double the risk of virological failure to first-line NNRTI-based ART.

Ecological aspects of nematode parasites of introduced salmonids from Valdivia river basin, Chile

Between 1986 and 1987 fishes distributed among the following species introduced in Chile, and from different sectors of the Valdivia river basin (39º30' - 40º00', 73º30' - 71º45'W), were examined: 348 Salmo trutta, 242 Salmo gairdneri, 24 Cyprinus carpio and 52 Gambusia affinis holbrooki. The presence of Camallanus corderoi and Contracaecum sp. in S. gairdneri and of C. corderoi in S. trutta is recorded in Chile for the first time. Cyprinus carpio and G. a. holbrooki did not present infections by nematodes. The prevalence and mean intensity of the infections by nematodes presented significant differences among some sectors of the Valdivia river basin. In general, the prevalence and intensity of the infections by C. corderoi were greater than those by Contracaecum sp. The infections in S. gairdneri were higher than in S. trutta. The sex of the hosts had no influence on the prevalence and intensity of the infections by both nematodes. The length of the hosts did have an influence, except in the case of the infections by Contracaecum sp. in S, gairdneri. The infrapopulations of both nematode species showed over dispersion in most cases. The diet of the examined salmonids suggests that they would become infected principally throught the consuption of autochthonous fishes.

In vivo differentiation of Trypanosoma cruzi - 1. Experimental evidence of the influence of vector species on metacyclogenesis

Vector species has not hitherto been studied as influencing metacyclogenesis of Trypanosoma cruzi, while the role of the parasite strain has been frequently stressed as of dominant importance in this process. In order to fill this gap in our knowledge, metacyclogenesis was monitored in nine triatomine species. The first part of this paper presents photographs of the main and intermediate parasite stages in each vector species studied. In the second part of the study the proportional distribution of all these forms, as seen in Giemsa stained smears is summarized, thus providing an opportunity to analyze both: the length of time between the ingestion of the blood trypomastigotes and the appearance of metacyclic forms and the rates of developmental stages leading to these latter. The most remarkable observation was that metacyclogenesis rates in vivo appear to be vector dependent, reaching 50 in Rhodnius neglectus, 37 in its congener R. prolixus and being dramatically lower in the majority of Triatoma species (5 in T. sordida, 3 in T. brasiliensis and 0 in T. pseudomaculata) at the 120th day of infection. These observations suggest that through screening of different vector species it is possible to find some that are capable of minimizing or maximizing metacyclic production.

FOXC2 controls formation and maturation of lymphatic collecting vessels through cooperation with NFATc1.

The mechanisms of blood vessel maturation into distinct parts of the blood vasculature such as arteries, veins, and capillaries have been the subject of intense investigation over recent years. In contrast, our knowledge of lymphatic vessel maturation is still fragmentary. In this study, we provide a molecular and morphological characterization of the major steps in the maturation of the primary lymphatic capillary plexus into collecting lymphatic vessels during development and show that forkhead transcription factor Foxc2 controls this process. We further identify transcription factor NFATc1 as a novel regulator of lymphatic development and describe a previously unsuspected link between NFATc1 and Foxc2 in the regulation of lymphatic maturation. We also provide a genome-wide map of FOXC2-binding sites in lymphatic endothelial cells, identify a novel consensus FOXC2 sequence, and show that NFATc1 physically interacts with FOXC2-binding enhancers. As damage to collecting vessels is a major cause of lymphatic dysfunction in humans, our results suggest that FOXC2 and NFATc1 are potential targets for therapeutic intervention.

Nematode parasites of Brazilian piciformes birds: a general survey with description of Procyrnea anterovulvata n. sp. (Habronematoidea, Habronematidae)

Thirty species of nematodes recovered from Piciformes hosts are reported. Procyrnea anterovulvata n. sp. from Chelidoptera tenebrosa brasiliensis is described and compared to P. colaptes and P. pileata. The considered morphometric parameters are mainly related to the ratio between length of the body/distance of the vulva to the anterior end. It is approximately 1:0.5 in P. colaptes and P. pileata compared to 1:0.1 in the new species. The male of Synhimantus (Dispharynx) crassissima is described for the first time. Thelazia (Thelaziella) spizaeti is revalidated and new records are reported for some species.

Description of the Immature Stages of Anopheles (Nyssorhynchus) rondoni (Neiva & Pinto) (Diptera: Culicidae)

The larval and pupal stages of Anopheles (Nyssorhynchus) rondoni (Neiva and Pinto) (Albimanus Section) are fully described and illustrated for the first time. The larval stage is similar to An. (Nys.) strodei Root. It can be recognized by the following combination of characters: clypeal index, 1.6-2.9; single, aciculate setae 2,3-C; seta 3-C 0.5-0.7 the length of 2-C; setae 1,2-P rarely sharing a common tubercle; seta 1-P with narrow leaflets. The pupal stage is distinguished from other Nyssorhynchus by having setae 1-IV-VII and 5-V-VII branched. Only minor variation was found in setal counts between specimens from Peixoto de Azevedo, State of Mato Grosso and Bocaina, State of São Paulo, Brazil