Direct comparison of the task-dependent discharge of M1 in hand space and muscle space.

Since its introduction in the early 1980s, the concept of a "preferred direction" for neuronal discharge has proven to be a powerful means of studying motor areas of the brain. In the current paper, we introduce the concept of a "muscle-space"-preferred direction (PD(M)) that is analogous to the familiar hand-space-preferred direction (PD(H)). PD(M) reflects the similarity between the discharge of a given neuron and the activity of each muscle in much the way that PD(H) reflects the similarity of discharge with motion along each of the three Cartesian coordinate axes. We used PD(M) to analyze the data recorded from neurons in the primary motor cortex (M1) of three different monkeys. The monkeys performed center-out movements within two different cubical workspaces centered either to the left or right of the monkey's shoulder while we simultaneously recorded neuronal discharge, muscle activity, and limb orientation. We calculated preferred directions in both hand space and muscle space, and computed the angles between these vectors under a variety of conditions. PDs for different neurons were broadly distributed throughout both hand space and muscle space, but the muscle-space vectors appeared to form clusters of functionally similar neurons. In general, repeated estimates of PD(M) were more stable over time than were similar estimates of PD(H). Likewise, there was less change in PD(M) than in PD(H) for data recorded from the two different workspaces. However, although a majority of neurons had this muscle-like property, a significant minority was more stable in Cartesian hand space, reflecting a heterogeneity of function within M1.

Prevalence, nature, severity and correlates of postpartum depressive symptoms in Vietnam.

OBJECTIVE: To examine depressive symptomatology in women after childbirth in Ho Chi Minh City, Vietnam. DESIGN: A cross sectional survey. SETTING: Hung Vuong Obstetrics and Gynaecology Hospital and the Maternal, Child Health and Family Planning Center of Ho Chi Minh City, Vietnam. POPULATION: Mothers of infants aged +/- six weeks attending well-baby clinics. METHOD: Participants were recruited consecutively in the postnatal wards and invited to take part in the study at the first clinic visit. Individual structured interviews about health and social circumstances, including the Edinburgh Postnatal Depression Scale (EPDS) were administered during clinic visits. The interview schedule was translated into Vietnamese, back translated for verification and piloted. Interviewers were specifically trained members of staff of the two centres. MAIN OUTCOME MEASURES: EPDS scores and responses to structured questions about specific and non-specific symptoms. RESULTS: Of 506 women who participated, 166 (33%) had EPDS scores in the clinical range of > 12 and 99 (19%) acknowledged suicidal ideation. In a forward stepwise logistic regression analysis, 77% of cases with EPDS scores > 12 were correctly classified in a model which included unwelcome pregnancy, lack of a permanent job, < 30 days complete rest after childbirth, an unsettled baby, not being given special foods, avoiding proscribed foods and being unable to confide in their husbands. CONCLUSION: Depressive symptomatology is more prevalent among parturient women in Ho Chi Minh City, Vietnam than reported rates in developed countries and is at present unrecognised.

Prediction of muscle activity by populations of sequentially recorded primary motor cortex neurons.

We have adopted an analysis that produces a post hoc prediction of the time course of electromyogram (EMG) activity from the discharge of ensembles of neurons recorded sequentially from the primary motor cortex (M1) of a monkey. Over several recording sessions, we collected data from 50 M1 neurons and several distal forelimb muscles during a stereotyped precision grip task. Ensemble averages were constructed from 5 to 10 trials for each neuron and EMG signal. We used multiple linear regression on randomly chosen subsets of these neurons to find the best fit between the neuronal and EMG data. The fixed delay between neuronal and EMG signals that yielded the largest coefficient of determination (R(2)) between predicted and actual EMG was 50 ms. R(2) averaged 0.83 for ensembles composed of 15 neurons. If, instead, each neuronal signal was delayed by the time of its peak cross-correlation with the EMG signal, R(2) increased to 0.88. Using all 50 neurons, R(2) under these conditions averaged nearly 0.97. A similar analysis was conducted with signals recorded during both a power grip and a precision grip task. Quality of the fit dropped dramatically when parameters from the precision grip for a given set of neurons were used to fit data recorded during the power grip. However, when a single set of regression parameters was used to fit a combination of the two tasks, the quality of the fits decreased by <10% from that of a single task.

Health technologies for the developing world. Promoting self-reliance through improving local procurement and manufacturing capabilities.

To reduce their dependency on donors or the international currency costs of essential health care products, developing countries are building or improving capability for local manufacturing or competitive international procurement. Through long-term strategic planning, public/private partnerships, collaboration with firms in industrialized nations, and farsighted donor policies, the capacity for alternative supply can be increased in stages from importation through local processing and packaging to full production and multiproduct enterprises.

Medicare Physician Payment Reform: implications for nurse practitioners.

In January 1992, the federal government implemented a package of physician payment reforms for use in the Medicare program. Among these reforms is a resource-based fee schedule that replaces the customary, prevailing, and reasonable (CPR) method of payment that has been used since Medicare's inception. This article describes the recommendations of the Physician Payment Review Commission, a Congressional advisory group, concerning the implications of the resource-based fee schedule on nurse practitioners and other non-physician practitioners. Absent changes in current law, services provided by nurse practitioners will be paid based on the same formulas that were used under CPR. This author advises that these payment formulas be revised to reflect the differences in resource costs borne by physicians and nonphysicians. Furthermore, revisions to the payment formulas should be made in the near future before the Medicare fee schedule and the rules governing its use are adopted by other public (e.g., Medicaid) and private payers.

Relationship between condom strength and failure during use.

The relationship between condom strength and failure during use was examined in six volunteers using artificially deteriorated condoms. Samples of each condom set exposed to ultraviolet light for three to eleven hours were tested for strength by air burst procedures. The remaining condoms were used by volunteers protected from pregnancy by other means. Burst pressure fell to 35% and burst volume to 17% of untreated levels after six hours of ultraviolet exposure. A maximum mean breakage rate during use of 30% was obtained at this time, although individuals experienced breakage rates up to 70% at this stage of deterioration. No failures occurred during use until condoms had deteriorated by more than 25%. Conclusions were: 1) that burst test parameters can effectively and sensitively measure changes in condom strength, 2) that condoms produced to western industrial standards carry a wide margin of strength over and above the minimum required for effective use, 3) that stored condoms should not necessarily be thrown out if they are uniform in strength but fall below original acceptance standards.

PIP: The relationship between condom strength and failure during use was examined in 6 volunteers using artificially deteriorated condoms. Samples of each condom set exposed to ultraviolet light for 3-11 hours were tested for strength by airburst procedures. The remaining ones were used by volunteers protected from pregnancy by other means. Burst pressure fell to 35% and burst volume to 17% of untreated levels after 6 hours of ultraviolet exposure. A maximum mean breakage rate during use of 30% was obtained at this stage of deterioration. No failures occurred during use until condoms had deteriorated by more than 25%. Conclusions were: 1) that burst test parameters can effectively and sensitively measure changes in condom strength; 2) that condoms produced to western industrial standards carry a wide margin of strength over and above the minimum required for effective use; and 3) that stored condoms need not be thrown out if they are uniform in strength but fall below original acceptance standards.

Advances in sterilization equipment.

From the array of sterilization procedures that are safe, simple and effective, the service provider must select procedures that fit his or her logistical criteria, which include the cost and maintenance of equipment, availability of supplies, and training of the requisite personnel. In this paper, these criteria are discussed for each of the various sterilization procedures. Information about female sterilization equipment for conventional postpartum laparotomy, minilaparotomy, colpotomy, laparoscopy, and culdoscopy is presented, together with facts about the related tubal occlusion techniques. The standard ligation techniques for male sterilization are compared with the newer electrocoagulation and thermocoagulation methods. A variety of methods for both female and male sterilization that are in the research stage are also mentioned. It is concluded that, from a programmatic point of view, vasectomy and postpartum ligation via laparotomy are the optimal sterilization procedures. For women who have not recently been pregnant, minilaparotomy with a standard tubal ligation technique is recommended, except in large teaching hospitals where laparoscopy can be performed efficiently.