Substitution-Newton-Raphson method applied to the modeling of a vapour compression refrigeration system using different representations of the thermodynamic properties of R-134a

This paper gives a detailed presentation of the Substitution-Newton-Raphson method, suitable for large sparse non-linear systems. It combines the Successive Substitution method and the Newton-Raphson method in such way as to take the best advantages of both, keeping the convergence features of the Newton-Raphson with the low requirements of memory and time of the Successive Substitution schemes. The large system is solved employing few effective variables, using the greatest possible part of the model equations in substitution fashion to fix the remaining variables, but maintaining the convergence characteristics of the Newton-Raphson. The methodology is exemplified through a simple algebraic system, and applied to a simple thermodynamic, mechanical and heat transfer modeling of a single-stage vapor compression refrigeration system. Three distinct approaches for reproducing the thermodynamic properties of the refrigerant R-134a are compared: the linear interpolation from tabulated data, the use of polynomial fitted curves and the use of functions derived from the Helmholtz free energy.

Intergenerational representations of schistosomiasis in endemic area, Jaboticatubas, Minas Gerais

The analysis of the intergenerational process of disease/health representations constitutes a requisite for the construction of projects and health education interventions. The objective of this work is to describe the meaning attributed to schistosomiasis in the family context. Twenty-one residents of an endemic area were interviewed. The interviews were submitted to content analysis. The results demonstrated different representations of the disease by the children, parents and grandparents. This paper discusses the differences in these representations and its impact in schistosomiasis control programs.

Social Representations Of Violence Against Rural Women: Unveiling Senses In Multiple Views

We analyze the social representations of violence against women from the perspective of city managers, professionals and health workers in rural settings of the southern half of Rio Grande do Sul. The study has a qualitative approach and adds a theoretical/methodological perspective of social representations. The data were generated by means of the associative method, question-stimulus of words and expressions emergence. The analysis of word association was performed with EVOC software, considering frequency and order of association with inducing terms. Participants recognize violence against women as gender destination that induces consent, resignation, guilt and fear, and results in naturalization and trivialization of this social phenomenon. We highlight the need to produce ruptures in established and traditional forms of health care, in the conservative and stereotypical views of violence, favoring access to friendly service and avoiding the reproduction of gender inequalities.


The representations of adolescents about gynecological consultation

Objective: To analyze the social representation of adolescents about gynecological consultation and the influence of those in searching for consultations. Method: Qualitative descriptive study based on the Social Representations Theory, conducted with 50 adolescents in their last year of middle school. The data was collected between April and May of 2010 by Evocations and a Focal Group. The software EVOC and contextual analysis were used in the data treatment. Results: The elements fear and constraint, constant in the central nucleus, can justify the low frequency of adolescents in consultations. The term embarrassment in the peripheral system reinforce current sociocultural norms, while prevention, associated with learning about sex and clarifying doubts, allows to envision an educative function. Obtained testimonies in the focal groups exemplify and reinforce those findings. Conclusion: For an effective health education, professionals, including nurses, need to clarify the youth individually and collectively about their rights to privacy, secrecy, in addition to focus the gynecological consultation as a promotion measure to sexual and reproductive health.

In the context of a daycare center: nursing and their representations of child care as an educational act

This study aimed to analyze the social representations in the professionals of technical staff, who work with children at USP daycare centers. Eight professionals of the nursing field underwent a semi-structured interview. The interviews were recorded and transcribed in their entirety and the content of the discourse was subjected to thematic-categorical analysis. The categories were transformed into variables and processed by the software Classification Hiérarchique Classificatoire et Cohésitive (CHIC®) and analyzed by the hierarchical similarity tree. The results indicate that actions to promote health are reported as educational and transformative, in which health care gains new meaning through contextualized conceptions in the field of child education. We conclude that professionals attribute new meanings to their practices in the health care environment of daycare centers as their representations shifts from the logic of the biomedical field to a logic of educational care. In this sense, they perceive themselves as being challenged to establish an interaction with the children in terms of their activities related to the promotion of health and in an educational act.

Mental ill health in the elderly: medical students’ social representations in the United Kingdom

Objective This study aims to explore medical students’ social representations of mental ill health in older adults. Method It comprises an exploratory and qualitative investigation based on the theory of social representations. Two focus groups with pre-clinical medics (group 1, N=4; group 2, N=4) and 10 individual interviews with clinical medical students were conducted. Thematic analysis at a latent level explored meanings and differences between groups. Results Three overarching themes reflect participants’ representations of mental health problems in later life – mental ill health in old age, polarisation of care, and challenges to care. Primary health care appears as an important strategy to overcome barriers to mental health care in the community. Nevertheless, disqualifying representations, stigma and organization of services constitute the main challenges to quality mental health care in later life. Conclusion This paper highlights the need to address cultural and organizational barriers to promote quality care.

Central nervous system involvement in Chagas' disease: an updating

A review was made of the available literature on central nervous system (CNS) involvement in Chagas' disease. Thirty-one works concerning the acute nervous form and 17 others dealing with the chronic nervous form, all presenting neuropathologic studies, were critically analysed. Based on this analysis, an attempt was made to establish the possible natural history of CNS involvement in Chagas' disease. Among others, the following facts stand out: 1) the initial, acute phase of Trypanosoma cruzi infection is usually asymptomatic and subclinical; 2) only a small percentage of cases develop encephalitis in the acute phase of Chagas' disease; 3) the symptomatic acute forms accompanied by chagasic encephalitis are grave, with death ensuing in virtually all cases as a result of the brain lesions per se or of acute chagasic myocarditis, this being usually intense and always present; 4) individuals with the asymptomatic acute form and with the mild symptomatic acute form probably have no CNS infection or, in some cases, they may have discrete encephalitis in sparse foci. In the latter case, regression of the lesions may be total, or residual inflammatory nodules of relative insignificance may persist. Thus, no anatomical basis exists that might characterize the existence of a chronic nervous form of Chagas' disease; 5) reactivation of the CNS infection in the chronic form of Chagas' disease is uncommon and occurs only in immunosuppressed patients.

Candida esophagitis: species distribution and risk factors for infection

Although Candida albicans is the main cause of fungal esophagitis, other species such as C. tropicalis, C. krusei and C. stellatoidea have also been implicated. Several studies have identified risk factors for C. albicans esophagitis. However, data for non-C. albicans species is still sparse. The aim of this study was to determine the etiology of Candida esophagitis in our medical centre over an 18-month period. Additionally, we aimed to investigate predisposing conditions for esophageal candidosis caused by different Candida species. A total of 21,248 upper gastroscopies were performed in Santa Casa Complexo Hospitalar between January 2005 and July 2006. The prevalence of Candida esophagitis was 0.74% (n = 158). C. albicans caused the vast majority of infections (96.2%), followed by C. tropicalis (2.5%), C. lusitaniae (0.6%) and C. glabrata (0.6%). There were 81 women (51.3%) and 77 men (48.7%). No case of mixed infection occurred. Concomitant oral candidosis was documented for 10.8% (n = 17). Most of cases (55.1%) involved outpatients. Around one fifth of patients in our cohort had no identifiable risk factors for esophageal candidosis (20.8%). Since nearly all infections were caused by C. albicans we were not able to determine risk factors for esophagitis caused by other Candida species.

Ocular lesions in gerbils (Meriones unguiculatus) infected with low larval burden of Toxocara canis: observations using indirect binocular ophthalmoscopy

To study the frequency of ocular lesions in 30 gerbils infected with 100 embryonated eggs of Toxocara canis, indirect binocular ophthalmoscopy was performed 3, 10, 17, 24, 31 and 38 days after infection. All the animals presented larvae in the tissues and 80% presented ocular lesions. Hemorrhagic foci in the choroid and retina were present in 92% of the animals with ocular lesions. Retinal exudative lesions, vitreous lesions, vasculitis and retinal detachment were less frequent. Mobile larvae or larval tracks were observed in four (13.3%) animals. Histological examination confirmed the ophthalmoscopic observations, showing that the lesions were focal and sparse. In one animal, there was a larva in the retina, without inflammatory reaction around it. The results demonstrated that gerbils presented frequent ocular lesions after infection with Toxocara canis, even when infected with a small number of embryonated eggs. The lesions observed were focal, consisting mainly of hemorrhages with signs of reabsorption or inflammation in different segments of eye, and differing from the granulomatous lesions described in ocular larva migrans in humans.