Effect of external fields in Axelrod's model of social dynamics

The study of the effects of spatially uniform fields on the steady-state properties of Axelrod's model has yielded plenty of counterintuitive results. Here, we reexamine the impact of this type of field for a selection of parameters such that the field-free steady state of the model is heterogeneous or multicultural. Analyses of both one- and two-dimensional versions of Axelrod's model indicate that the steady state remains heterogeneous regardless of the value of the field strength. Turning on the field leads to a discontinuous decrease on the number of cultural domains, which we argue is due to the instability of zero-field heterogeneous absorbing configurations. We find, however, that spatially nonuniform fields that implement a consensus rule among the neighborhood of the agents enforce homogenization. Although the overall effects of the fields are essentially the same irrespective of the dimensionality of the model, we argue that the dimensionality has a significant impact on the stability of the field-free homogeneous steady state.

Influence of Prey Size on the Capture of Social Wasps (Hymenoptera: Vespidae) by the Orb-Web Spider Nephilengys cruentata

The objective of the present study was to evaluate the plasticity of the hunting behavior of the spider Nephilengys cruentata (Araneae: Nephilidae) facing different species of social wasps. Considering that wasps can consume various species of spiders and that their poison can be used as defense against many predators, the effect of the corporal size of the prey was evaluated in the behavior of N. cruentata. Predation experiments were conducted using three species of social wasps of different sizes and the data registered in this research were compiled through annotations and filming of the hunting behavior of each spider, in relation to the offered prey. The results revealed that the size of the wasp and the sequential offer of prey change the hunting behavior of the spider, and prey of large size have high influence on this behavior.

A Spatial Propensity Score Matching Evaluation of the Social Impacts of Sugarcane Growing on Municipalities in Brazil

The expansion of sugarcane growing in Brazil, spurred particularly by increased demand for ethanol, has triggered the need to evaluate the economic, social, and environmental impacts of this process, both on the country as a whole and on the growing regions. Even though the balance of costs and benefits is positive from an overall standpoint, this may not be so in specific producing regions, due to negative externalities. The objective of this paper is to estimate the effect of growing sugarcane on the human development index (HDI) and its sub-indices in cane producing regions. In the literature on matching effects, this is interpreted as the effect of the treatment on the treated. Location effects are controlled by spatial econometric techniques, giving rise to the spatial propensity score matching model. The authors analyze 424 minimum comparable areas (MCAs) in the treatment group, compared with 907 MCAs in the control group. The results suggest that the presence of sugarcane growing in these areas is not relevant to determine their social conditions, whether for better or worse. It is thus likely that public policies, especially those focused directly on improving education, health, and income generation/distribution, have much more noticeable effects on the municipal HDI.

Late-onset social anxiety disorder following traumatic brain injury

Background: Neuropsychiatric sequelae are the predominant long-term disability after traumatic brain injury (TBI). This study reports a case of late-onset social anxiety disorder (SAD) following TBI. Case report: A patient that was spontaneous and extroverted up to 18-years-old started to exhibit significant social anxiety symptoms. These symptoms became progressively worse and he sought treatment at age 21. He had a previous history of traumatic brain injury (TBI) at age 17. Neuroimaging investigations (CT, SPECT and MRI) showed a bony protuberance on the left frontal bone, with mass effect on the left frontal lobe. He had no neurological signs or symptoms. The patient underwent neurosurgery with gross total resection of the lesion and the pathological examination was compatible with intradiploic haematoma. Conclusions: Psychiatric symptoms may be the only findings in the initial manifestation of slowly growing extra-axial space-occupying lesions that compress the frontal lobe from the outside. Focal neurological symptoms may occur only when the lesion becomes large. This case report underscores the need for careful exclusion of general medical conditions and TBI history in cases of late-onset SAD and may also contribute to the elucidation of the neurobiology of this disorder.

Does ragging play a role in medical student depression - Cause or effect?

Background: Medical students experience a lot of stress what may contribute to symptoms of depression. In this study we set out to look at the environmental factors which may be contributing in one medical school in Brazil. Methods: We assessed depressive symptoms using Beck's Depression Inventory in 465 and 267 medical students in 2001 and 2006 respectively. We explored possible social and environmental causes using qualitative data. Results: Nearly 15% scored above the cut off for depression in both the samples. Males in the pre-clinical stage in 2006 showed an increase in depressive symptoms than males in the same cycle in 2001 (aOR = 7.36 [95% CI = 0.85-63.5] p = 0.07). Qualitative data confirmed that factors such as ragging and low social involvement were correlated with depressive symptoms in pre-clinical stage males. Limitations: The sample size was small both for quantitative and qualitative aspects of the study. Conclusions: It appears that ragging plays an important role in the genesis of depressive symptoms in medical students. (C) 2012 Elsevier B.V. All rights reserved.

Relationship between body size and flying-related structures in Neotropical social wasps (Polistinae, Vespidae, Hymenoptera)

Body size influences wing shape and associated muscles in flying animals which is a conspicuous phenomenon in insects, given their wide range in body size. Despite the significance of this, to date, no detailed study has been conducted across a group of species with similar biology allowing a look at specific relationship between body size and flying structures. Neotropical social vespids are a model group to study this problem as they are strong predators that rely heavily on flight while exhibiting a wide range in body size. In this paper we describe the variation in both wing shape, as wing planform, and mesosoma muscle size along the body size gradient of the Neotropical social wasps and discuss the potential factors affecting these changes. Analyses of 56 species were conducted using geometric morphometrics for the wings and lineal morphometrics for the body; independent contrast method regressions were used to correct for the phylogenetic effect. Smaller vespid species exhibit rounded wings, veins that are more concentrated in the proximal region, larger stigmata and the mesosoma is proportionally larger than in larger species. Meanwhile, larger species have more elongated wings, more distally extended venation, smaller stigmata and a proportionally smaller mesosoma. The differences in wing shape and other traits could be related to differences in flight demands caused by smaller and larger body sizes. Species around the extremes of body size distribution may invest more in flight muscle mass than species of intermediate sizes.

Anxiolytic-like effect of oxytocin in the simulated public speaking test

Oxytocin (OT) is known to be involved in anxiety, as well as cardiovascular and hormonal regulation. The objective of this study was to assess the acute effect of intranasally administered OT on subjective states, as well as cardiovascular and endocrine parameters, in healthy volunteers (n = 14) performing a simulated public speaking test. OT or placebo was administered intranasally 50 min before the test. Assessments were made across time during the experimental session: (1) baseline (-30 min); (2) pre-test (-15 min); (3) anticipation of the speech (50 min); (4) during the speech (1:03 h), post-test time 1 (1:26 h), and post-test time 2 (1:46 h). Subjective states were evaluated by self-assessment scales. Cortisol serum and plasma adrenocorticotropic hormone (ACTH) were measured. Additionally, heart rate, blood pressure, skin conductance, and the number of spontaneous fluctuations in skin conductance were measured. Compared with placebo, OT reduced the Visual Analogue Mood Scale (VAMS) anxiety index during the pre-test phase only, while increasing sedation at the pre-test, anticipation, and speech phases. OT also lowered the skin conductance level at the pre-test, anticipation, speech, and post-test 2 phases. Other parameters evaluated were not significantly affected by OT. The present results show that OT reduces anticipatory anxiety, but does not affect public speaking fear, suggesting that this hormone has anxiolytic properties.

Desigualdade social e os estudos epidemiológicos: uma reflexão

Os indicadores sociais se tornaram imprescindíveis no elenco de variáveis dos estudos epidemiológicos a partir da constatação de que a determinação dos agravos à saúde é complexa e multidimensional. Nessa perspectiva, a desigualdade social vem ocupando destaque como um fator explicativo das condições de saúde das populações. O objetivo é discutir as diferentes concepções que norteiam a seleção dos indicadores utilizados nos estudos epidemiológicos e abordar os efeitos psicossociais nos seres humanos acarretados pela desigualdade social. Foi realizada uma revisão da literatura acerca dos estudos epidemiológicos que utilizaram os indicadores de desigualdade social e capital social para uma melhor compreensão dos problemas de saúde, bem como uma investigação no campo da sociologia e da psicologia social. De acordo com a pesquisa pode-se constatar que há controvérsias sobre o efeito da desigualdade social na saúde humana pelo fato desses indicadores serem baseados, majoritariamente, pela renda e capacidade de consumo dos indivíduos. Da mesma forma, os indicadores de capital social em nível cognitivo e estrutural são muito limitados para compreender o dinamismo das relações sociais. Nesse sentido, são necessários mais estudos para a construção de indicadores sociais que contemplem a complexidade das sociedades modernas.

An ecological economic interpretation of the Jevons effect

This article develops an ecological economic interpretation of the Jevons effect. Moreover, it is argued that under the neoclassical paradigm there are no elements with which to foresee the long-term existence of this phenomenon. The objective of these arguments is to demonstrate that the Jevons effect can be used to compare the ability of neoclassical and ecological economics describing the social appropriation of nature. This is elaborated in two steps. First, we show the importance of the thesis that the economy cannot be cut off from the biophysical materiality of what is produced to give consistency to the so-called Khazzoom-Brookes postulate. It is made clear that this supposition is exogenous to the neoclassical paradigm. Second, the supposition of the biophysical materiality of what is produced is utilized to make an ecological economic interpretation of the Jevons effect. Afterwards, a comparison is made between the neoclassical and the ecological economic perspectives. This comparison leads to the following conclusions: (i) the persistent presence of the Jevons effect in the long run is an anomaly in the neoclassical paradigm; (ii) the observation of the non-existence of the Jevons effect is a refutation of the supposition that economic growth and biophysical materiality are not separable, a central thesis defended by ecological economists. This situation makes possible to use the Jevons effect as a 'laboratory test' to compare the ability of neoclassical and ecological economic paradigms to describe the social appropriation of nature. (C) 20111 Elsevier B.V. All rights reserved.