2,323 research outputs found
Swordtail Fry Attend to Chemical and Visual Cues in Detecting Predators and Conspecifics
Predation pressure and energy requirements present particularly salient opposing selective pressures on young fish. Thus, fry are expected to possess sophisticated means of detecting predators and resources. Here we tested the hypotheses that fry of the swordtail fish Xiphophorus birchmanni use chemical and visual cues in detection of predators and conspecifics. To test these hypotheses we presented young (<7 day-old) fry with combinations of visual and chemical stimuli from adult conspecifics and predators. We found that exposure to predator odors resulted in shoal tightening similar to that observed when fry were presented with visual cues alone. In trials with conspecific stimuli, fry were particularly attracted to adult conspecifics when presented simultaneous visual and chemical stimuli compared to the visual stimulus alone. These results show that fry attend to the odors of adult conspecifics, whose presence in a particular area may signal the location of resources as well as an absence of predators. This is one of the first studies to show that such young fish use chemical and visual cues in predator detection and in interactions with conspecifics. Previous research in X. birchmanni has shown that anthropogenic alteration of the chemical environment disrupts intraspecific chemical communication among adults; we suggest that because fry use the same chemosensory pathways to detect predators and conspecifics, alteration of the chemical environment may critically disrupt predator and resource detection
Recommended from our members
Comparison of 5-year progression of retinitis pigmentosa involving the posterior pole among siblings by means of SD-OCT: a retrospective study
The blockchain technology promises to transform finance, money and evengovernments. However, analyses of blockchain applicability and robustness typicallyfocus on isolated systems whose actors contribute mainly by running the consensusalgorithm. Here, we highlight the importance of considering trustless platformswithin the broader ecosystem that includes social and communication networks. Asan example, we analyse the flash-crash observed on 21st June 2017 in the Ethereumplatform and show that a major phenomenon of social coordination led to acatastrophic cascade of events across several interconnected systems. We proposethe concept of “emergent centralisation” to describe situations where a single systembecomes critically important for the functioning of the whole ecosystem, and arguethat such situations are likely to become more and more frequent in interconnectedsocio-technical systems. We anticipate that the systemic approach we propose willhave implications for future assessments of trustless systems and call for the attentionof policy-makers on the fragility of our interconnected and rapidly changing world
Cardiac CT and MRI guide surgery in impending left ventricular rupture after acute myocardial infarction
We report the case of a 67 year-old patient who presented with worsening chest pain and shortness of breath, four days post acute myocardial infarction. Contrast enhanced computed tomography of the chest ruled out a pulmonary embolus but revealed an unexpected small subepicardial aneurysm (SEA) in the lateral left ventricular wall which was confirmed on cardiac magnetic resonance imaging. Intraoperative palpation of the left lateral wall was guided by the cardiac MRI and CT findings and confirmed the presence of focally thinned and weakened myocardium, covered by epicardial fat. An aneurysmorrhaphy was subsequently performed in addition to coronary bypass surgery and a mitral valve repair. The patient was discharged home on post operative day eight in good condition and is feeling well 2 years after surgery
ACUTE KIDNEY INJURY CAUSED BY Crotalus AND Bothrops SNAKE VENOM: A REVIEW OF EPIDEMIOLOGY, CLINICAL MANIFESTATIONS AND TREATMENT
SUMMARY Ophidic accidents are an important public health problem due to their incidence, morbidity and mortality. An increasing number of cases have been registered in Brazil in the last few years. Several studies point to the importance of knowing the clinical complications and adequate approach in these accidents. However, knowledge about the risk factors is not enough and there are an increasing number of deaths due to these accidents in Brazil. In this context, acute kidney injury (AKI) appears as one of the main causes of death and consequences for these victims, which are mainly young males working in rural areas. Snakes of the Bothrops and Crotalus genera are the main responsible for renal involvement in ophidic accidents in South America. The present study is a literature review of AKI caused by Bothrops and Crotalus snake venom regarding diverse characteristics, emphasizing the most appropriate therapeutic approach for these cases. Recent studies have been carried out searching for complementary therapies for the treatment of ophidic accidents, including the use of lipoic acid, simvastatin and allopurinol. Some plants, such as Apocynaceae, Lamiaceae and Rubiaceae seem to have a beneficial role in the treatment of this type of envenomation. Future studies will certainly find new therapeutic measures for ophidic accidents
Balanço e análise da sustentabilidade energética na produção orgânica de hortaliças.
Os insumos e serviços utilizados na produção vegetal representam custo energético. Dependendo desses fatores e das produtividades obtidas, a conversão da produção em energia determinará a eficiência energética do sistema. A agricultura orgânica somente atingirá a missão de preservação ambiental se tiver comprovada sustentabilidade energética. Neste trabalho, objetivou-se caracterizar os balanços energéticos dos cultivos orgânicos e analisar sua sustentabilidade, em comparação aos sistemas convencionais. Monitoraram-se campos de produção de dez culturas, de 1991 a 2000 em Domingos Martins-ES. Os dados do sistema convencional foram obtidos pelas médias dos coeficientes técnicos da região. Quantificaram-se os coeficientes técnicos, convertendo suas grandezas físicas em equivalentes energéticos, expressos em kcal. O sistema orgânico gastou 4.571.159 kcal ha-1 e apresentou 12.696.712 kcal ha-1 de energia inserida na colheita, mostrando balanço médio de 2,78. Esse valor foi similar ao obtido no sistema convencional (1,93). As participações dos componentes nos gastos do sistema orgânico foram embalagem (35,8%), composto orgânico (17,2%), irrigação (12,6%), sementes/mudas (12,4%) e mão-de-obra (11,0%), serviços mecânicos (5,0%) e frete (4,5%). Se os custos com embalagens fossem eliminados, os gastos do sistema orgânico seriam reduzidos para 2.930.113 kcal ha-1, aumentando sua eficiência. A maioria dos cultivos orgânicos pode ser considerada sustentável em transformação de energia, com balanços superiores a 1,00 e produção média diária de 80.421 kcal ha-1 por dia, superior à necessidade mínima de 58.064 kcal ha-1
Phylogenetic relationships within Chamaecrista sect. Xerocalyx (Leguminosae, Caesalpinioideae) inferred from the cpDNA trnE-trnT intergenic spacer and nrDNA ITS sequences
Chamaecrista belongs to subtribe Cassiinae (Caesalpinioideae), and it comprises over 330 species, divided into six sections. The section Xerocalyx has been subjected to a profound taxonomic shuffling over the years. Therefore, we conducted a phylogenetic analysis using a cpDNA trnE-trnT intergenic spacer and nrDNA ITS/5.8S sequences from Cassiinae taxa, in an attempt to elucidate the relationships within this section from Chamaecrista. The tree topology was congruent between the two data sets studied in which the monophyly of the genus Chamaecrista was strongly supported. Our analyses reinforce that new sectional boundaries must be defined in the Chamaecrista genus, especially the inclusion of sections Caliciopsis and Xerocalyx in sect. Chamaecrista, considered here paraphyletic. The section Xerocalyx was strongly supported as monophyletic; however, the current data did not show C. ramosa (microphyllous) and C. desvauxii (macrophyllous) and their respective varieties in distinct clades, suggesting that speciation events are still ongoing in these specimens
Genome of the Avirulent Human-Infective Trypanosome—Trypanosoma rangeli
Background: Trypanosoma rangeli is a hemoflagellate protozoan parasite infecting humans and other wild and domestic mammals across Central and South America. It does not cause human disease, but it can be mistaken for the etiologic agent of Chagas disease, Trypanosoma cruzi. We have sequenced the T. rangeli genome to provide new tools for elucidating the distinct and intriguing biology of this species and the key pathways related to interaction with its arthropod and mammalian hosts. Methodology/Principal Findings: The T. rangeli haploid genome is ,24 Mb in length, and is the smallest and least repetitive trypanosomatid genome sequenced thus far. This parasite genome has shorter subtelomeric sequences compared to those of T. cruzi and T. brucei; displays intraspecific karyotype variability and lacks minichromosomes. Of the predicted 7,613 protein coding sequences, functional annotations could be determined for 2,415, while 5,043 are hypothetical proteins, some with evidence of protein expression. 7,101 genes (93%) are shared with other trypanosomatids that infect humans. An ortholog of the dcl2 gene involved in the T. brucei RNAi pathway was found in T. rangeli, but the RNAi machinery is non-functional since the other genes in this pathway are pseudogenized. T. rangeli is highly susceptible to oxidative stress, a phenotype that may be explained by a smaller number of anti-oxidant defense enzymes and heatshock proteins. Conclusions/Significance: Phylogenetic comparison of nuclear and mitochondrial genes indicates that T. rangeli and T. cruzi are equidistant from T. brucei. In addition to revealing new aspects of trypanosome co-evolution within the vertebrate and invertebrate hosts, comparative genomic analysis with pathogenic trypanosomatids provides valuable new information that can be further explored with the aim of developing better diagnostic tools and/or therapeutic targets
Workloads and strain process in Community Health Agents
ABSTRACT OBJECTIVE To identify the workloads present in the work activities of community health agents (CHAs) and the resulting strain processes. METHOD A descriptive, exploratory, cross-sectional and quantitative study conducted with 137 CHAs. Data were collected through a questionnaire and interview guided by the health surveillance software called SIMOSTE (Health Monitoring System of Nursing Workers), following the ethical codes of the current law. RESULTS In total, were identified 140 workloads involved in 122 strain processes, represented by the occurrence of health problems of the CHAs. The mechanical (55.00%) and biological (16.43%) loads stood out. The most common strain processes were the external causes of morbidity and mortality (62.31%) and diseases of the musculoskeletal system and connective tissue (10.66%). CONCLUSION From the identified overloads, it became evident that all workloads are present in the work process of CHAs, highlighting the mechanical load, represented mainly by external causes of morbidity and mortality that are related to occupational accidents
- …