A simple and fast method for estimating bat roost locations

Bats play a pivotal role in pest control, pollination and seed dispersal. Despite their ecological significance, locating bat roosts remains a challenging task for ecologists. Traditional field surveys are time-consuming, expensive and may disturb sensitive bat populations. In this article, we combine data from static audio detectors with a bat movement model to facilitate the detection of bat roosts. Crucially, our technique not only provides a point prediction for the most likely location of a bat roost, but because of the algorithm's speed, it can be applied over an entire landscape, resulting in a likelihood map, which provides optimal searching regions. To illustrate the success of the algorithm and highlight limitations, we apply our technique to greater horseshoe bat (Rhinolophus ferrumequinum) acoustic data acquired from six surveys from four different UK locations and over six different times in the year. Furthermore, we investigate what happens to the accuracy of our predictions in the case that the roost is not contained within the area spanned by the detectors. This innovative approach to searching rural environments holds the potential to greatly reduce the labour required for roost finding, and, hence, enhance the conservation efforts of bat populations and their habitats.

Bat Motion can be Described by Leap Frogging

We present models of bat motion derived from radio-tracking data collected over 14 nights. The data presents an initial dispersal period and a return to roost period. Although a simple diffusion model fits the initial dispersal motion we show that simple convection cannot provide a description of the bats returning to their roost. By extending our model to include non-autonomous parameters, or a leap frogging form of motion, where bats on the exterior move back first, we find we are able to accurately capture the bat's motion. We discuss ways of distinguishing between the two movement descriptions and, finally, consider how the different motion descriptions would impact a bat's hunting strategy.

Burden and cost of inpatient care for HIV-positive paediatric patients--status in the Cape Town metropole during the second week of March 1999. Paediatric HIV Census Group

OBJECTIVE

To determine the burden of the HIV epidemic on paediatric inpatient facilities in the teaching hospitals of the Cape metropole and tributaries to these hospitals.

SETTING

Second- and third-level hospitals.

METHOD

During the second week of March 1999 a multicentre collaborative census was performed of all paediatric beds in the teaching hospitals of Cape Town and all facilities draining to and from them.

RESULTS

One hundred and six HIV-infected patients were identified from a total of 1,264 beds. Thirty-nine children were in second-level beds or in a long-term residential facility. Fifty-six children were in second-level beds designated for acute care, and occupied 12% of all such beds. Ten children were in beds designated for the care of tuberculosis. Thirty-two (56%) of the acute admissions were for gastro-enteritis, and 13 (23%) were for pneumonia. In 10 children (18% of all admissions) recognised complications of HIV infection were direct causes of admission. For 29 children (35% of all admissions) the current admission was the first; the remainder had had a mean of 2.4 previous admissions. Fourteen children (25%) had received oxygen, and 26 (46%) had received intravenous therapy. Mean lifetime hospitalisation cost per infected child was calculated to be R19,712. The projected cost of a local initiative to reduce mother-to-child transmission is between R8,326 and R10,806 per vertical infection prevented.

CONCLUSION

The inpatient burden of HIV-infected children in Cape Town reflects an early stage of the epidemic. Compared with projected lifetime hospitalisation cost for infected children, an intervention to reduce vertical transmission cost would be cost effective.

Transition from paediatric to adult care for persons with cystic fibrosis: patient and parent perspectives

OBJECTIVES

To gauge the perspectives of adolescents and adults with cystic fibrosis (CF) and their parents regarding the transition from paediatric to adult-oriented health care.

METHODS

Cross-sectional survey using an anonymous, semi-structured questionnaire. The study population consisted of adolescents and adults attending a paediatric and an adult CF clinic in Cape Town, South Africa and their parents.

RESULTS

Forty-seven of the 61 subjects completed the questionnaire (response rate 77%). Autonomy in health care was 'extremely important' to most persons with CF. Transfer at the age of 16-18 years of age was the preferred option for most respondents. Whereas over 80% of parents felt their children needed more CF-related information, only 38% of adolescents expressed this need (P < 0.05). Adolescents also reported little need for general health information. More than 80% of respondents were 'unsure' about transfer. Over 90% felt that a transition clinic would be useful. As viewed by the respondents, its main purpose would be to provide information about the adult clinic and an opportunity to meet the CF doctor in the adult clinic.

CONCLUSION

There are significant concerns about the transition process in this population. Given the expressed need for autonomy and a transition clinic, the basis for a smoother transition in the future has been laid.

Informed consent--a survey of doctors' practices in South Africa

OBJECTIVE

To examine doctors' practices with regard to informed consent.

DESIGN

Cross-sectional, descriptive survey.

PARTICIPANTS AND SETTING

All full-time consultants and registrars in the Departments of Medicine, Obstetrics and Gynaecology, Paediatrics and Child Health, Paediatric Surgery and Surgery at the University of Cape Town were included. The overall response rate was 63% (160/254).

MEASUREMENT

Data were collected by means of self-administered, semi-structured questionnaires.

RESULTS

Most doctors (79%) felt it was their responsibility to ensure that patients and parents were fully informed about diagnostic and therapeutic interventions. Many (62%) supported a patient-centred standard for determining the type and amount of information to disclose. Doctors disclose most of the legally required information except for information about alternative forms of treatment and remote serious risks. They almost never provide information on medical costs. The most common reasons for not obtaining informed consent were the doctors' tendency to 'tell' patients/parents what they intend doing and their belief that patients/parents expect doctors to know what is medically best for them. Language, inadequate communication skills and lack of time were, surprisingly, seldom viewed as obstacles to the obtaining of informed consent. Findings were independent of discipline (medical or surgical) and doctors' status (consultant or registrar). Doctors who treat children were significantly less likely to obtain consent for certain interventions.

CONCLUSION

Doctors meet many, but not all, of the legal requirements for informed consent. The findings question whether informed consent as envisioned by the law exists in reality. Cross-cultural research is needed to clarify patients' and parents' expectations of informed consent.

Bed use in the medical wards of Red Cross War Memorial Children's Hospital, Cape Town

OBJECTIVE

To determine extent of appropriate (medically necessary) and inappropriate bed use and level of care (LOC) needed by patients admitted to hospital.

DESIGN

A cross-sectional, descriptive survey.

SETTING

Medical wards of Red Cross War Memorial Children's Hospital (RCCH), a teaching hospital of the University of Cape Town.

MEASUREMENT AND RESULTS

A 25% sample of beds was selected randomly each day for 12 consecutive days during September-October 1990. Data were collected using a questionnaire based on the Pediatric Appropriateness Evaluation Protocol and the Delay Tool. A subjective measure of LOC was developed. Questionnaires were completed for 171 admissions and 365 patient days; 98% of admissions and 79.5% of patient days were medically justified, and 49% of admissions needed tertiary care. The remaining 51% could have been treated by general paediatricians (17%) or medical officers (32%) in community hospitals. Of delays (unnecessary patient days) 62% were hospital-related, 20% were family-related and 18% were related to inadequate lower level institutional care and outpatient services.

CONCLUSION

RCCH is functioning as a general, specialist and super-specialist hospital. Its future role as a tertiary referral centre will depend on adequate provision of community-based care. Further cost-benefit research is needed to address areas of inappropriate bed use identified in this study.