Variable targeting and reduction in large vector autoregressions with applications to workforce indicators.

We develop statistical tools for time series analysis of large multivariate datasets, when a few core series are of principal interest and there are many potential auxiliary predictive variables. The methodology, based on Vector Autoregressions (VAR), handles the case where unrestricted fitting is precluded by a large number of series and a huge parameter space. In particular, we adopt a forecast error criterion and use Granger-causality tests in a sequential manner to build a VAR model that targets the main variables. This approach affects variable reduction (or equivalently, sparsity restrictions) in a computationally fast way that remains feasible for large dimensions. The search for the best model results in a VAR, fitted with a selection of supporting series, that has the best possible forecast performance with respect to the core variables. We apply the statistical methodology to model real Gross Domestic Product and the national Unemployment Rate, two time series widely monitored by economists and policy-makers, based on a large set of Quarterly Workforce Indicators comprising various major sectors of the economy and different measures of labor market conditions.

Understanding the barriers to clubfoot treatment adherence in Uganda: a rapid ethnographic study.

PURPOSE: The Ponseti method has been demonstrated to be an effective, low-technology method of correcting congenital clubfoot. The purpose of this paper is to identify barriers to adherence to the Ponseti method of clubfoot treatment in Uganda. Understanding of barriers underlies successful and culturally appropriate approaches to program implementation. METHOD: A qualitative study (rapid ethnographic study), using semi-structured interviews, focus groups and observation, was conducted. Interviews were conducted with parents of children with clubfoot (42), adults with clubfoot (2), community leaders (40), traditional healers (39) and practitioners treating clubfoot (38). Some 48 focus groups (24 male, 24 female) were conducted with general community members to ascertain their opinions on the potential barriers. The data was collected by a team of researchers in 8 districts of Uganda over the period of one month. It was then coded manually by the researchers and sorted into themes. RESULTS: The barriers to adherence were classified into 6 themes: (i) problems with programmatic resource availability and regional differences, (ii) distance to treatment site, (iii) poverty, (iv) lack of paternal support, (v) caregiver's other responsibilities, and (vi) challenges of the treatment process. A number of factors that were helpful for encouraging adherence were also identified: (i) outreach and follow-up services, (ii) counselling/caregiver-practitioner partnership, (iii) family harmony and solidarity, and (iv) receiving quality care. CONCLUSIONS: Our study highlights the barriers to adherence in the treatment of clubfoot, as well as factors that could be helpful for overcoming these barriers. This information provides health planners with knowledge to assist them in meeting the needs of the population and implementing effective and appropriate awareness and treatment programs for clubfoot in Uganda.

Ontogenetic change in relative performance of allozyme genotypes influences detection of heterosis in the earthworm Eisenia andrei.

The effect of ontogeny on relationships between allozyme genotypes and fresh weight was measured weekly throughout the life history of the earthworm Eisenia andrei to test the hypothesis that there is an ontogenetic component to variation in such relationships. Two of six allozyme loci showed a significant increase in apparent heterosis with ontogeny, while one locus showed a significant decrease in apparent heterosis. Three loci showed a significant decrease in the performance of common homozygotes with ontogeny. Patterns of relative genotypic performance varied among loci, but the cumulative effect was an increase in apparent allozyme heterosis later in ontogeny coinciding with a series of positive relationships between multilocus heterozygosity and fresh weight. The results could not be used to determine whether these patterns were caused by selection acting on the loci directly or on loci tightly linked to allozyme loci. However, because the same individuals were used throughout this study and thus allele frequencies and heterozygote deficiency were constant, the presence of both ontogenetic effects and differences in such patterns among loci is not compatible with a general inbreeding effect. Examining relative genotypic performance repetitively using the same individuals through ontogeny or in different environments is a very powerful experimental design for testing the effects of inbreeding or other populational factors.

Extinction-colonization dynamics structure genetic variation of spotted sunfish (Lepomis punctatus) in the Florida Everglades.

The population genetics of aquatic animals in the Florida Everglades may be strongly influenced by extinction and colonization dynamics. We combined analyses of allozyme and microsatellite loci to test the hypothesis that two levels of population structure are present for spotted sunfish (Pisces: Centrarchidae: Lepomis punctatus) inhabiting the Everglades. We hypothesized that annual cycles of marsh dry-down increase local-scale genetic variation through a process of local extinction and colonization; we hypothesized that barriers to gene flow by levee/canal systems create a second, regional level of genetic variation. In 1996 and 1997, we sampled spotted sunfish from 11 Everglades sites that were distributed in three regions separated by levees. We documented patterns of genetic variation at 7 polymorphic allozyme loci and 5 polymorphic microsatellite loci. Most genetic variation was present among local populations, according to both types of genetic markers. Furthermore, samples from marsh sites were heterogeneous, while those from canals were not. These data supported our hypothesis that dry-down events and local population dynamics in the marsh have a significant effect on population genetic structure of spotted sunfish. We found no support for our hypothesis that water-management structures superimpose a second level of genetic structure on this species, possibly because canals obscure historical structure by facilitating gene flow or because the complete canal system has been in place for fewer than 20 generations of this species. Our data suggests a continent-island (canal-marsh) structure of populations with high gene flow among regions and recurrent mixing in marshes from canal and creek habitats.

To do or not to do: desirability and consistency mediate judgements of regret.

In 4 studies, the authors demonstrated that when errors associated with action were inconsistent with decision nakers' orientation, they were undesirable and produced more regret than did errors associated with inaction. Conversely, when errors associated with action were consistent with decision makers' orientation. they were desirable and produced less regret than did errors associated with inaction. Desirability and consistency mediated this relationship, independent of mutability. These results were obtained when judgments and decisions to act or not act were made in close temporal proximity to one another as well as when participants reflected on their past decisions. The authors provide an analysis of when counterfactuals would and would not be expected to mediate judgments of normality and regret.

Heterosis in two closely related species of earthworm (Eisenia fetida and E. andrei).

The importance of heterosis, and in particular allozyme-associated heterosis, in natural populations remains unclear. Much of the scepticism that surrounds allozyme-associated heterosis comes from inconsistent and unreliable detection of the relationship. Thus, evaluating the genetic mechanisms that may cause allozyme-associated heterosis in natural populations has proven difficult. The most prevalent hypotheses that have been put forward to explain the genetic basis of heterosis are the general dominance and the local overdominance hypotheses. A factorial crossing design was used to survey eight polymorphic allozyme loci in the parent and offspring generations of two species of earthworms in order to evaluate possible mechanisms of allozyme-associated heterosis for growth rate. Significant heritable variation for growth rate was detected only within a single cross. Allozyme-associated heterosis for growth rate was detected only within this cross. This relationship did not persist after the effects of interfamily variation were removed. These results indicate that simple heritability of a fitness-related trait may be necessary for predictive power and repeatability of allozyme-associated heterosis, and that the allozyme-associated heterosis detected in this study was the result of general dominant genetic effects.

Voice rehabilitation practices among head and neck surgeons.

Voice rehabilitation practices among head and neck surgeons were surveyed to determine the proportional contribution of various methods of speech support and the impact of recent developments in this field. Of the 400 head and neck surgeons contacted, 212 (53%) responded and 196 provided data. Noninvasive methods of speech support continue to predominate in this country. Esophageal speech is used by all surgeons in some of their patients. The introduction of tracheoesophageal puncture techniques for prosthetic placement has added a new dimension to speech rehabilitation and is used almost 30% of the time by those who use it (88% of surgeons surveyed). The proportional use of the most common methods of speech support is almost identical between head and neck surgeons of a general surgical background and otolaryngologists. The incidence of total failures to achieve voice rehabilitation is less than 10%.

Acetic acid vapor levels associated with facial prosthetics.

The use of Silastic Medical Adhesive Type A in the fabrication of facial prostheses may cause health hazards to the patient and the operator because of acetic acid emissions. Caution must be exercised to remove acetic acid vapors from the air and unliberated acetic acid from material applied directly to the skin.

Infection in the patient receiving chemotherapy for cancer: oral considerations.

Because of the various factors associated with the disease process and its treatment, the patient receiving chemotherapy for cancer is highly susceptible to infection, and infection accounts for approximately 70% of patient fatalities. When potential sources of infection are considered in the patient receiving chemotherapy for cancer, the mouth provides ideal conditions for microbial growth, particularly in the debilitated patient, and is a portal of entry for contamination of the lungs, the digestive tract, and the circulatory system. These patients are more susceptible to oral infection because of alteration of oral flora toward greater pathogenicity and impairment of host-defense mechanisms. Oral/dental management of the patient receiving chemotherapy for cancer will enhance the general health and comfort of the patient and will prevent or reduce oral complications including mucositis and local and systemic infection.