Polarization vision and its role in biological signaling

Visual pigments, the molecules in photoreceptors that initiate the process of vision, are inherently dichroic, differentially absorbing light according to its axis of polarization. Many animals have taken advantage of this property to build receptor systems capable of analyzing the polarization of incoming light, as polarized light is abundant in natural scenes (commonly being produced by scattering or reflection). Such polarization sensitivity has long been associated with behavioral tasks like orientation or navigation. However, only recently have we become aware that it can be incorporated into a high-level visual perception akin to color vision, permitting segmentation of a viewed scene into regions that differ in their polarization. By analogy to color vision, we call this capacity polarization vision. It is apparently used for tasks like those that color vision specializes in: contrast enhancement, camouflage breaking, object recognition, and signal detection and discrimination. While color is very useful in terrestrial or shallow-water environments, it is an unreliable cue deeper in water due to the spectral modification of light as it travels through water of various depths or of varying optical quality. Here, polarization vision has special utility and consequently has evolved in numerous marine species, as well as at least one terrestrial animal. In this review, we consider recent findings concerning polarization vision and its significance in biological signaling.

Presentation and mechanisms of concussion in professional Rugby League football

The present study prospectively recorded the circumstances, incidence, mechanisms, injury detection and presentation of concussion in Rugby League. Forty-three consecutive concussions were recorded over three competitive seasons in 175 professional Rugby League players. Data showed (i) the incidence of concussion ranged from 5.9 to 9.8 injuries/1000 player hours across grades - except when age-group players were mismatched (18.4); (ii) 'head-high tackles' accounted for a significant number of concussions; (iii) concussion rarely involved a loss of consciousness with the most common indicators of concussion being amnesia, headache and unsteadiness, with the mechanism of injury often missed; and (iv) concussion often occurs concurrently with other injuries. Concussion (including repeated episodes) is a common injury in Rugby League. Systematic mental status questioning is warranted whenever concussion is suspected. Coaches, trainers and players need more education in the recognition and management of concussion. Stricter penalties for illegal 'head-high' tackling are strongly recommended.

Facial Palsy After Blunt Trauma and Without Facial Bone Fracture

A 14-year-old patient had a low-energy facial blunt trauma that evolved to right facial paralysis caused by parotid hematoma with parotid salivary gland lesion. Computed tomography and angiography demonstrated intraparotid collection without pseudoaneurysm and without radiologic signs of fracture in the face. The patient was treated with serial punctures for hematoma deflation, resolving with regression and complete remission of facial paralysis, with no late sequela. The authors discuss the relationship between facial nerve traumatic injuries associated or not with the presence of facial fractures, emphasizing the importance of early recognition and appropriate treatment of such cases.

The awareness of chronic fatigue syndrome: A comparative study in Brazil and the United Kingdom

Objective: While in many Western affluent countries there is widespread awareness of chronic fatigue syndrome (CFS), also known as myalgic encephalomyelitis (ME), little is known about the awareness of CFS/ME in low- and middle-income countries. We compared the awareness of CFS in Brazil and the United Kingdom. Methods: Recognition and knowledge of CFS were assessed among 120 Brazilian specialist doctors in two major university hospitals using a typical case vignette of CFS. We also surveyed 3914 and 2435 consecutive attenders in Brazilian and British primary care clinics, respectively, concerning their awareness of CFS. Results: When given a typical case vignette of CFS, only 30.8% [95% confidence interval (CI), 22.7-39.9%] of Brazilian specialist doctors mentioned chronic fatigue or CFS as a possible diagnosis, a proportion substantially lower than that observed in Western affluent countries. Similarly, only 16.2% (95% CI, 15.1-17.4%) of Brazilian primary care attenders were aware of CFS, in contrast to 55.1% (95% CI, 53.1-57.1%) of their British counterparts (P <.001). This difference remained highly significant after controlling for patients` sociodemographic and socioeconomic characteristics (P <.001). Conclusions: The awareness of CFS was substantially lower in Brazil than the United Kingdom. The observed difference may influence patients` help-seeking behavior and both doctors` and patients` beliefs and attitudes in relation to fatigue-related syndromes. Attempts to promote the awareness of CFS should be considered in Brazil, but careful plans are required to ensure the delivery of sound evidence-based information. (c) 2008 Elsevier Inc. All rights reserved.

Effects of sex hormonal levels and phases of the menstrual cycle in the processing of emotional faces

Several neuropsychiatry disorders have shown a sexual dimorphism in their incidence, symptom profile and therapeutic response. A better understanding of the impact of sex hormones in emotional processing sexual dimorphism could bring tight to this important clinical finding. Some studies have provided evidence of sex differences in the identification of emotional faces, however, results are inconsistent and such inconsistency could be related to the lack of experimental control of the sex hormone status of participants. More recently, a few studies evaluated the modulation of facial emotion recognition by the phase of the menstrual cycle and sex hormones, however, none of them directly compared these results with a group of men. We evaluated the accuracy of facial emotion recognition in 40 healthy volunteers. Eleven women were assigned to early follicular group, nine women to the ovulatory group and 10 women to luteal group, depending on the phase of menstrual cycle, and a group of 10 men were also evaluated. Estrogen, progesterone and testosterone levels were assessed. The performance of the groups in the identification of emotional faces varied depending on the emotion. Early follicular group were more accurate to perceive angry faces than all other groups. Sadness was more accurately recognized by early follicular group than by luteal group and regarding the recognition of fearful faces a trend to a better performance and a significantly higher accuracy was observed, respectively, in the early follicular group and in the ovulatory group, in comparison to men. In women, estrogen negatively correlated to the accuracy in perception of angry mate faces. Our results indicate sex hormones to be implicated in a sexual dimorphism in facial emotion recognition, and highlight the importance of estrogen specifically in the recognition of negative emotions such as sadness, anger and fear. (C) 2009 Elsevier Ltd. All rights reserved.

Mental evolution and development: Evidence for secondary representation in children, great apes, and other animals

Recent interest in the development and evolution of theory of mind has provided a wealth of information about representational skills in both children and animals, According to J, Perrier (1991), children begin to entertain secondary representations in the 2nd year of life. This advance manifests in their passing hidden displacement tasks, engaging in pretense and means-ends reasoning, interpreting external representations, displaying mirror self-recognition and empathic behavior, and showing an early understanding of mind and imitation. New data show a cluster of mental accomplishments in great apes that is very similar to that observed in 2-year-old humans. It is suggested that it is most parsimonious to assume that this cognitive profile is of homologous origin and that great apes possess secondary representational capacity. Evidence from animals other than apes is scant. This analysis leads to a number of predictions for future research.

Effects of temporal association on recognition memory

The influence of temporal association on the representation and recognition of objects was investigated. Observers were shown sequences of novel faces in which the identity of the face changed as the head rotated. As a result, observers showed a tendency to treat the views as if they were of the same person. Additional experiments revealed that this was only true if the training sequences depicted head rotations rather than jumbled views: in other words, the sequence had to be spatially as well as temporally smooth. Results suggest that we are continuously associating views of objects to support later recognition, and that we do so not only on the basis of the physical similarity, but also the correlated appearance in time of the objects.

E-cadherin homophilic ligation directly signals through Rac and phosphatidylinositol 3-kinase to regulate adhesive contacts

Classical cadherins mediate cell recognition and cohesion in many tissues of the body. It is increasingly apparent that dynamic cadherin contacts play key roles during morphogenesis and that a range of cell signals are activated as cells form contacts with one another. It has been difficult, however, to determine whether these signals represent direct downstream consequences of cadherin ligation or are juxtacrine signals that are activated when cadherin adhesion brings cell surfaces together but are not direct downstream targets of cadherin signaling. In this study, we used a functional cadherin ligand (hE/Fc) to directly test whether E-cadherin ligation regulates phosphatidylinositol 3-kinase (PI 3-kinase) and Rac signaling. We report that homophilic cadherin ligation recruits Rae to nascent adhesive contacts and specifically stimulates Rae signaling. Adhesion to hE/Fc also recruits PI 3-kinase to the cadherin complex, leading to the production of phosphatidylinositol 3,4,5-trisphosphate in nascent cadherin contacts. Rae activation involved an early phase, which was PI 3-kinase-independent, and a later amplification phase, which was inhibited by wortmannin. PI 3-kinase and Rae activity were necessary for productive adhesive contacts to form following initial homophilic ligation. We conclude that E-cadherin is a cellular receptor that is activated upon homophilic ligation to signal through PI 3-kinase and Rae. We propose that a key function of these cadherin-activated signals is to control adhesive contacts, probably via regulation of the actin cytoskeleton, which ultimately serves to mediate adhesive cell-cell recognition.

Synthesis and structural analysis of the N-terminal domain of the thyroid hormone-binding protein transthyretin

Transthyretin (TTR) is a 55 kDa protein responsible for the transport of thyroid hormones and retinol in human serum. Misfolded forms of the protein are implicated in the amyloid diseases familial amyloidotic polyneuropathy and senile systemic amyloidosis. Its folding properties and stabilization by ligands are of current interest due to their importance in understanding and combating these diseases. To assist in such studies we developed a method for the solid phase synthesis of the monomeric unit of a TTR analogue and its folding to form a functional 55 kDa tetramer. The monomeric unit of the protein was chemically synthesized in three parts, comprising amino acid residues 151, 5499 and 102127, and ligated using chemoselective thioether ligation chemistry. The synthetic protein was folded and assembled to a tetrameric structure in the presence of the TTRs native ligand, thyroxine, as shown by gel filtration chromatography, native gel electrophoresis, TTR antibody recognition and thyroid hormone binding. In the current study the solution structure of the first of these fragment peptides, TTR(151) is examined to determine its intrinsic propensity to form beta-sheet structure, potentially involved in amyloid fibril formation by TTR. Despite the presence of extensive beta-structure in the native form of the protein, the Nterminal fragment adopts an essentially random coil conformation in solution.

Alcohol and other drug use disorders among older-aged people

In Australia people aged 65 years or older currently comprise 12.1% of the population. This has been estimated to rise to 24.2% by 2051. Until recently there has been relatively little research on alcohol and other drug use disorders among these individuals but, given the ageing population, this issue is likely to become of increasing importance and prominence. Epidemiological research shows a strong age-related decline in the prevalence of alcohol and other drug use disorders with age. Possible reasons for this include: age-related declines in the use and misuse of alcohol and other drugs; increased mortality among those with a lifetime history of alcohol and other drug use disorders; historical differences in exposure to and use of alcohol and other drugs. Despite the age-related decline in the prevalence of these disorders, they do still occur among those aged 65 years or older and, given historical changes in exposure to and use of illicit drugs, it likely that the prevalence of these disorders among older-aged individuals will rise. Specific issues faced by older-aged individuals with alcohol and other drug use problems are discussed. These include: interactions with prescribed medications, under-recognition and treatment of alcohol and drug problems, unintentional injury and social isolation. Finally, a brief discussion of treatment issues is provided.

The medicine and epidemiology of bovine respiratory disease in feedlots

Bovine Respiratory Disease (BRD) results from a complex, multifactorial interaction of stressors, animal susceptibility, and respiratory pathogens. The infectious agents associated with BRD are ubiquitous among cattle populations. Typically, one or a combination of stressors are necessary to initiate BRD. Prevention of BRD should, therefore, address management procedures to minimise stressors. Administration of vaccines against BRD agents may help reduce the incidence of BRD but is unlikely to eliminate the condition. The effectiveness of antimicrobials in the treatment of BIRD depends primarily on early recognition and treatment. The use of antioxidant vitamins, minerals or other agents in the prevention and treatment of BRD warrants further research.

Performance management framework: the fit between PM framework adopted in Portuguese local government and the Otley’s framework

Purpose/objectives: This paper seeks to investigate whether performance management (PM) framework adopted in Portuguese local government (PLG) fit the Otley’s PM framework (1999). In particularly, the research questions are (1) whether PM framework adopted in PLG (SIADAP) fit the Otley´s framework, and (2) how local politicians (aldermen) see the operation of performance management systems (PMS) in PLG (focusing on the goal-setting process and incentive and reward structures). Theoretical positioning/contributions: With this paper we intend to contribute to literature on how the Otley’s PM framework can guide empirical research about the operation of PMS. In particular, the paper contributes to understand the fit between PMS implemented in PLG and the Otley´s PM framework. The analysis of this fit can be a good contribution to understand if PMS are used in PLG as a management tool or as a strategic response to external pressures (based on interviews conducted to aldermen). We believe that the Otley’s PM framework, as well as the extended PM framework presented by Ferreira and Otley (2009), can provide a useful research tool to understand the operation of PMS in PLG. Research method: The first research question is the central issue in this paper and is analyzed based on the main reforms introduced by Portuguese government on PM of public organizations (like municipalities). On the other hand, interviews conducted on three larger Portuguese municipalities (Oporto, Braga, and Matosinhos) show how aldermen see the operation of PMS in PLG, highlighting the goals setting process with targets associated and the existing of incentive and reward structures linked with performance. Findings: Generally we find that formal and regulated PM frameworks in PLG fit the main issues of the Otley’s PM framework. However, regarding the aldermen perceptions about PMS in practice we find a gap between theory and practice, especially regarding difficulties associated with the lack of a culture of goals and targets setting and the lack of incentive and reward structures linked with performance.

Earnings management and economic crises in the brazilian capital market

The 2008 economic crisis challenged accounting, either demanding recognition and measurement criteria well adjusted to this scenario or even questioning its ability to inform appropriately entities' financial situation before the crisis occurred. So, our purpose was to verify if during economic crises listed companies in the Brazilian capital market tended to adopt earnings management (EM) practices. Our sample consisted in 3,772 firm-years observations, in 13 years - 1997 to 2009. We developed regression models considering discretionary accruals as EM proxy (dependent variable), crisis as a macroeconomic factor (dummy variable of interest), ROA, market-to-book, size, leverage, foreign direct investment (FDI) and sector as control variables. Different for previous EM studies two approaches were used in data panel regression models and multiple crises were observed simultaneously. Statistics tests revealed a significant relation between economic crisis and EM practices concerning listed companies in Brazil in both approaches used.

Motivations and management factors of volunteer work in nonprofit organisations: a literature review

The objective of this paper is to review and discuss the literature about volunteers’ motivations to donate their time to NPOs and the management factors that can influence volunteer work. Firstly, the paper illustrates and compares the different types of motivation followed by a presentation of a typology that organises the volunteers’ motivations into four types: (i) altruism, (ii) belonging, (iii) ego and social recognition and (iv) development and learning. Secondly we discuss the key management factors in volunteering: recruitment, training and rewarding. Finally, we present four gaps in the literature that justify the scope for further research: (i) omission of differences between motivations related to volunteers’ "Attraction" versus "Retention"; (ii) focus of the research on the USA, UK and Australia context; (iii) absence of comparative analyses that relate motivations by NPO types and (iv) comprehension of how management factors (recruitment, training and rewarding) influence volunteers’ satisfaction and retention.

Diffuse liver disease classification from ultrasound surface characterization, clinical and laboratorial data

In this work liver contour is semi-automatically segmented and quantified in order to help the identification and diagnosis of diffuse liver disease. The features extracted from the liver contour are jointly used with clinical and laboratorial data in the staging process. The classification results of a support vector machine, a Bayesian and a k-nearest neighbor classifier are compared. A population of 88 patients at five different stages of diffuse liver disease and a leave-one-out cross-validation strategy are used in the classification process. The best results are obtained using the k-nearest neighbor classifier, with an overall accuracy of 80.68%. The good performance of the proposed method shows a reliable indicator that can improve the information in the staging of diffuse liver disease.