248 research outputs found
The prospect of rising in rank is key to long-term stability in Tibetan macaque society
One of the most fundamental questions in behavioural biology is why societies can persist for a long period of time. While researchers in animal behaviour have been hindered by a lack of an aggregate measure (such as social mobility) to quantify the dynamics of animal societies, researchers in social sciences have been challenged by the complexity and diversity of human societies. As a result, direct empirical evidence is still lacking for the hypothesized causal relationship between social mobility and social stability. Here we attempt to fill the void by examining a much simpler society in the Tibetan macaque (Macaca thibetana), which we have tracked for 30 consecutive years. By testing two group level hypotheses based on benefit-cost analysis and social stratification, we show the first quantitative evidence that an annual 2-to-1 stay/change ratio in the hierarchy with a 3-to-1 upward/downward ratio in intragenerational social mobility provides a substantive expected benefit for adult members to stay in the group and wait for their chances to advance. Furthermore, using a Markov transition matrix constructed from empirical data, we demonstrate that the 3-to-1 upward/downward ratio could lead to long-term structural stability in Tibetan macaque society
Reproductive biology of Thamnodynastes hypoconia (Serpentes: Dipsadidae) in Brazilian subtemperate wetlands
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New multiresponsive chromic soft materials: dynamic interconversion of short 2,7-dicyanomethylenecarbazole-based biradicaloid and the corresponding cyclophane tetramer
This work reports on a quinodimethane-type molecule, 2,7-dicyanomethylene-9-(2-ethylhexyl)carbazole (1), one of the shortest π-conjugated biradicaloids reported to be stable in solution under ambient conditions. This carbazole-based quinoidal precursor is able to form a macrocyclic σ-bonded tetramer (2). The resolved single-crystal X-ray structure of tetramer 2 shows that four molecules of 1 are linked together through four long (CN)2C−C(CN)2 bonds (1.631 Å) resulting from coupling of the unpaired electrons in biradicaloid 1. Dynamic interconversion between monomer 1 and cyclophane tetramer 2 is achieved by reversible cleavage and recovery of the four (CN)2C−C(CN)2 bonds upon soft external stimuli (light absorption, temperature and pressure), which is accompanied by significant color changes. These novel photo-, thermo-, and mechanochromic properties expand the versatility of π-conjugated biradicaloid compounds as novel functional materials that, in combination with spin chemistry and dynamic covalent chemistry, can be relevant in molecular machines, sensors, and switches
Evolution of the global inequality in greenhouse gases emissions using multidimensional generalized entropy measures.
Given the cumulative consequences of climate change, global concentration of greenhouse gases (GHGs) must be reduced; being inequality in per-capita emissions levels a problem to achieve a commitment by all countries. Thus, the evolution of carbon dioxide (CO2) emissions inequality has received special attention because CO2 is the most abundant GHG in the atmosphere. However, it is necessary to consider other gases to provide a real illustration of our starting point to achieve a multilateral agreement. In this paper, we study the evolution of global inequality in GHGs emissions during the period 1990–2011, considering the four main gases: CO2, methane (CH4), nitrous oxide (N2O) and fluorinated gases (F-gases). The data used in this analysis is taken from the World Resources Institute (2014) and the groups of countries are constructed according to the quantity of emissions that each country released into the atmosphere in the first year of study. For this purpose we use the multidimensional generalized entropy measures proposed by Maasoumi (1986)
that can be decomposable into the between- and within-group inequality components. The biggest fall in inequality is observed when we attach more weight to the emissions transfers between the most polluting countries and assume a low substitution degree among pollutants. Finally, some economic policy implications are commented.The authors thank the Ministerio de Economía y Competitividad (Project ECO2013-
48326-C2-2-P) and the Ministerio de Educación, Cultura y Deporte (FPU13/02155) for
the partial support of this work
Obstructive sleep apnea syndrome in children: Epidemiology, pathophysiology, diagnosis and sequelae
The prevalence of pediatric obstructive sleep apnea syndrome (OSAS) is approximately 3% in children. Adenotonsillar hypertrophy is the most common cause of OSAS in children, and obesity, hypotonic neuromuscular diseases, and craniofacial anomalies are other major risk factors. Snoring is the most common presenting complaint in children with OSAS, but the clinical presentation varies according to age. Agitated sleep with frequent postural changes, excessive sweating, or abnormal sleep positions such as hyperextension of neck or abnormal prone position may suggest a sleep-disordered breathing. Night terror, sleepwalking, and enuresis are frequently associated, during slow-wave sleep, with sleep-disordered breathing. Excessive daytime sleepiness becomes apparent in older children, whereas hyperactivity or inattention is usually predominant in younger children. Morning headache and poor appetite may also be present. As the cortical arousal threshold is higher in children, arousals are not easily developed and their sleep architectures are usually more conserved than those of adults. Untreated OSAS in children may result in various problems such as cognitive deficits, attention deficit/hyperactivity disorder, poor academic achievement, and emotional instability. Mild pulmonary hypertension is not uncommon. Rarely, cardiovascular complications such as cor pulmonale, heart failure, and systemic hypertension may develop in untreated cases. Failure to thrive and delayed development are serious problems in younger children with OSAS. Diagnosis of pediatric OSAS should be based on snoring, relevant history of sleep disruption, findings of any narrow or collapsible portions of upper airway, and confirmed by polysomnography. Early diagnosis of pediatric OSAS is critical to prevent complications with appropriate interventions
The Phospholipid Scramblases 1 and 4 Are Cellular Receptors for the Secretory Leukocyte Protease Inhibitor and Interact with CD4 at the Plasma Membrane
Secretory leukocyte protease inhibitor (SLPI) is secreted by epithelial cells in all the mucosal fluids such as saliva, cervical mucus, as well in the seminal liquid. At the physiological concentrations found in saliva, SLPI has a specific antiviral activity against HIV-1 that is related to the perturbation of the virus entry process at a stage posterior to the interaction of the viral surface glycoprotein with the CD4 receptor. Here, we confirm that recombinant SLPI is able to inhibit HIV-1 infection of primary T lymphocytes, and show that SLPI can also inhibit the transfer of HIV-1 virions from primary monocyte-derived dendritic cells to autologous T lymphocytes. At the molecular level, we show that SLPI is a ligand for the phospholipid scramblase 1 (PLSCR1) and PLSCR4, membrane proteins that are involved in the regulation of the movements of phospholipids between the inner and outer leaflets of the plasma membrane. Interestingly, we reveal that PLSCR1 and PLSCR4 also interact directly with the CD4 receptor at the cell surface of T lymphocytes. We find that the same region of the cytoplasmic domain of PLSCR1 is involved in the binding to CD4 and SLPI. Since SLPI was able to disrupt the association between PLSCR1 and CD4, our data suggest that SLPI inhibits HIV-1 infection by modulating the interaction of the CD4 receptor with PLSCRs. These interactions may constitute new targets for antiviral intervention
All's well that begins Wells: Celebrating 60 years of Animal Behaviour and 36 years of research on anuran social behaviour
The scientific study of frogs and toads as important systems in behavioural ecology traces its roots to an influential review published in this journal 36 years ago (Wells 1977a, ‘The social behaviour of anuran amphibians’, Animal Behaviour, 25, 666–693). In just 28 pages, Wells summarized the state of knowledge on important behaviours associated with anuran breeding and introduced an evolutionary framework ‘for understanding the relationship between social behaviour and ecology’ (page 666) that was largely lacking in earlier treatments of this group. Not only is Wells's review one of the most cited papers ever published in Animal Behaviour, it is also responsible for setting broad research agendas and shaping much of our current thinking on social behaviour in an entire order of vertebrates. As such, it is entirely appropriate that we honour Wells's review and its contributions to the study of animal behaviour in this inaugural essay celebrating 12 papers selected by the community as the most influential papers published in the 60-year history of Animal Behaviour. In our essay, we place Wells's review in historical context at the dawn of behavioural ecology, highlight the field's progress in answering some major research questions outlined in the review, and provide our own prospectus for future research on the social behaviour of anuran amphibians.
Highlights
► This essay celebrates Kent Wells's (1977, Animal Behaviour, 25, 666–693) paper, ‘The social behaviour of anuran amphibians’. ► We place the article in historical context and outline its major contributions. ► We discuss progress on anuran social behaviour since its publication in 1977. ► We provide our own prospectus on the future of anuran behavioural ecology
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