New type of half-metallic antiferromagnet: transition metal pnictides.

The electronic structures of transition metal pnictides ABX(2), where A and B are the transition metal elements and X = N, P, As, Sb, and Bi, with the total valence d-electron number of the transition metal ions being ten, are investigated in the framework of the first-principles KKR Green's function method. Some possible crystal structures such as NiAs-type, NaCl-type, chalcopyrite, zinc-blende, wurtzite, and MnP-type structures are assumed. Similarly to chalcogenides, a new type of spin-compensated half-metallic ferrimagnet is found for the case of nitrides. The stability and magnetic transition temperature of these nitrides indicate that they are good candidates for spintronics materials. For other cases of pnictides such as P, As, Sb, and Bi, the half-metallicity seems not to be realized.

First-principles KKR-CPA calculation of interactions between concentration fluctuations.

The aim of this work is to develop the method of calculating atomic interactions in metals and semiconductors on the basis of first-principles electronic structure calculation. A new method to calculate the atomic interactions in the framework of KKR-CPA is proposed. In this approach two specific atoms embedded in a CPA medium are considered and the effects of both electron-electron interactions and multiple scattering, which are neglected in the generalized perturbation method (GPM), are fully taken into account. The calculated atomic interactions show that these effects are important for alloys containing transition-metal alloys such as FeAl. On the other hand, in the case of AuCu, where the d states lie considerably below the Fermi level, the effects are less important.

Do women with tuberculosis have a lower likelihood of getting diagnosed? Prevalence and case detection of sputum smear positive pulmonary TB, a population-based study from Vietnam.

OBJECTIVE: The aim was to estimate the gender-specific prevalence of tuberculosis (TB) through screening. A further aim was to calculate case detection within the Vietnamese National TB program. STUDY DESIGN AND SETTING: A population-based survey of 35,832 adults was performed within an existing sociodemographic longitudinal study in Bavi district, northern Vietnam. Cases were identified by a screening question about prolonged cough and further diagnosed with sputum examination and a chest X-ray. RESULTS: The estimated prevalence of pulmonary TB among men was 90/100,000 (95% CI 45-135/100,000) and among women 110/100,000 (95% CI 63-157/100,000). Case detection in the district was estimated to 39% (95% CI 20-76%) among men and 12% (95% CI 6-26%) among women. CONCLUSION: TB prevalence was similar among men and women. Case detection among men and women was significantly lower than the reported national case detection of 80%, and there was a significant underdetection of female cases. These findings warrant actions, and emphasize the need to perform similar studies in different contexts.

Fear and social isolation as consequences of tuberculosis in VietNam: a gender analysis.

SETTING: The study was conducted in four districts in different regions of Vietnam. OBJECTIVE: To describe the socio-economic consequences of tuberculosis (TB) in Vietnam with special reference to gender differentials concerning social stigma and isolation. DESIGN: Sixteen focus group discussions were carried out with men and women, TB patients and non-TB participants. Data was analysed using modified grounded theory technique. RESULTS: Generally, the participants had good knowledge about TB. However, knowledge and practice were not closely related in the sense that most non-TB participants perceived that TB can be successfully cured, while patients were seriously shocked when they were told that they had TB. Male patients often worried about economic-related problems, while female patients worried about social consequences of the disease. Both in the family and the community, isolation could be subtle, but it could also be obvious and had a tendency to continue much longer than medically justified. CONCLUSION: Information on stigma and isolation due to TB and gender differences is important for understanding patient dynamics and its effects on the disease. Tuberculosis control programmes need better understanding of the gender differences in attitudes and beliefs to improve case-detection and treatment outcome.

Health-seeking behaviour of individuals with a cough of more than 3 weeks.

Sex inequalities can lead to poorer access to health care and delays to diagnosis of tuberculosis in women. In a population-based survey we assessed health-seeking behaviour in adults with long-term cough. The prevalence of cough was 1% (213) and 2% (279) in men and women, respectively. Women took more health-care actions than men, but chose less qualified providers and reported lower health expenditure per visit. Delay before seeking hospital treatment was longer for women (41 days) than men (19 days; p=0.04), and more men (27; 36%) than women (14; 14%; p=0.0006) reported giving a sputum sample at hospital. Sex-sensitive strategies for tuberculosis control are needed and should take into account sex differences in health-care seeking behaviour as well as a possible sex bias among health-care providers.

Gender and tuberculosis control: perspectives on health seeking behaviour among men and women in Vietnam.

This study explores the perspectives of tuberculosis patients on which factors influenced their health seeking behaviour, with special reference to gender differentials in terms of delays in health seeking. In 1996, a multi-disciplinary research team carried out 16 focus group discussions. The study was done in four districts in Vietnam, both in the south and north of the country and in urban and rural areas. Qualitative analysis of data was performed following general principles of modified grounded theory technique. Participants in the focus groups described three main factors as contributing to delay in health seeking. These were fear of social isolation, economic constraints and inadequate staff attitudes and poor quality of health services. A model illustrating different factors influencing health seeking was elaborated and served as a basis for discussion of the findings. The main factor contributing to delay among women was described as fear of social isolation from the family or the community. Stigma was described as closely related to contextual factors such as gender-roles, socio-economic status and level of education and seemed to be mediated via denial and concealment of tuberculosis diagnosis and disease, thus causing delay. The main factor contributing to delay among men was described as fear of individual costs of diagnosis and treatment. Staff attitudes and quality of health service facilities were described as not always corresponding to people's expectations of appropriate health services. Women saw themselves and were seen by others as being more sensitive than men to poor service conditions and staff attitudes. A typical feature of the described health seeking behaviour of men was that they neglected symptoms until the disease reached a serious stage, by which time they tended to go directly to public health services without first visiting private health practitioners. Women, on the other hand, were described as having a tendency to seek out private services and practice self-medication before seeking care at public services. In conclusion, there is a need for better understanding of behavioural factors and for developing strategies, that take these into account. Health workers need to better understand gender and social aspects of tuberculosis control, particularly aspects that influence the likelihood for achieving equity in diagnosis and cure.

Attitudes to compliance with tuberculosis treatment among women and men in Vietnam.

SETTING: A study carried out in 1996 in four districts representing south and north as well as urban and rural areas of Vietnam. OBJECTIVE: To explore gender differences in knowledge, beliefs and attitudes towards tuberculosis and its treatment, and how these factors influence patients' compliance with treatment. DESIGN: Sixteen focus group discussions were performed by a multi-disciplinary research team from Vietnam and Sweden. Analysis was performed using modified Grounded Theory technique, specifically evaluating gender differences. RESULTS: Women were believed to be more compliant than men. Insufficient knowledge and individual cost during treatment were reported as main obstacles to compliance among men (poor patient compliance), while sensitivity to interaction with health staff and stigma in society (poor health staff and system compliance) were reported as the main obstacles among women. CONCLUSIONS: It is time to adopt a more comprehensive and gender-sensitive approach to compliance, which incorporates patient compliance, doctor compliance and system compliance, in order to fully support individual patients in their efforts to comply with treatment.

Different tuberculosis in men and women: beliefs from focus groups in Vietnam.

After decades in decline, tuberculosis (TB) has been increasing worldwide. In 1993, the World Health Organisation declared TB a global emergency. Passive case-finding is an important part of TB control programmes, and this is strongly affected by people's perceptions and beliefs of TB and society's behaviour towards TB sufferers. The aim of this study was to describe the perceptions and beliefs of Vietnamese people regarding TB and its risk factors with special reference to differences between men and women. Sixteen focus group discussions (FGDs) were organised in four districts representing different regions in Vietnam and consisting of men and women, TB patients and non-TB participants. In general, participants had good knowledge of TB being a dangerous, contagious and infectious disease, caused by germs. However, traditional beliefs in different types of TB still exist, mainly among older people in rural areas, but also resorted to by other people once ill. Four main types of TB were reported: (1) 'Lao truyen' (hereditary TB), handed down from older generations to latter ones through 'family blood', regardless of sexes; (2) 'Lao luc' (physical TB), caused by hard work, more men affected; (3) 'Lao tam' (mental TB), caused by too much worrying-more women affected; and (4) 'Lao phoi' (lung TB), dangerous and caused by TB germs, transmitted through the respiratory system-more men affected. Other general risk factors were also mentioned. Men were perceived to get TB more often than women, as they were more exposed to risk factors during both work and leisure time. These traditional beliefs may contribute to long delays to TB diagnosis and increased social stigma and isolation of TB patients and their families due to erroneous beliefs in transmission routes. Our findings demonstrate areas where TB control programmes may be improved.

Longer delays in tuberculosis diagnosis among women in Vietnam.

SETTING: Study conducted in 23 randomly selected districts in four provinces of Vietnam. OBJECTIVE: To describe and compare health seeking behaviour between men and women and to measure delays in tuberculosis (TB) diagnosis. DESIGN: All patients (n = 1027) aged 15-49 years with new smear-positive pulmonary TB detected in the selected districts during 1996 were interviewed using a structured questionnaire. RESULTS: Mean total delay to TB diagnosis was 13.3 weeks (95% confidence interval [CI] 11.5, 15.1) for women and 11.4 weeks (95% CI 10.6, 12.2) for men, including a patient's delay of 7.9 weeks (95% CI 6.5, 9.3) and 7.6 weeks (95% CI 6.9, 8.3) respectively. Doctor's delay was significantly longer among women (5.4 weeks, 95% CI 4.2, 6.6) than among men (3.8 weeks, 95% CI 3.3, 4.3). Women did not start seeking care later than men, nor did they have a different health seeking pattern. Women visited more health care providers than men (1.7 and 1.5 providers, respectively, P = 0.02). CONCLUSION: Patient's delay is unacceptably long for both men and women. Women do not receive a diagnosis of TB by doctors or other health care providers as quickly as men once they seek health care. The reasons for this gender difference warrant further investigations.