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Study Unit (study + unit)

Distribution by Scientific Domains
Life Sciences60%
Medical Sciences40%

Selected Abstracts

The relationship between local and regional diatom richness is mediated by the local and regional environment

GLOBAL ECOLOGY, Issue 3 2009
Sophia I. Passy
ABSTRACT Aim, In this continental study, species richness at local (LSR) and regional (RSR) scales was correlated and examined as a function of stream (local) and watershed (regional) environment in an effort to elucidate what factors control diatom biodiversity across scales. Location, Conterminous United States. Methods, Data on diatom richness, stream conditions and watershed properties were generated by the US Geological Survey. In the present investigation, RSR was estimated as the total diatom richness in a hydrologic study unit and, together with stream and watershed characteristics, was included in stepwise multiple regressions of LSR. The unique and shared contributions of RSR, stream and watershed environment to the explained variance in LSR were determined by variance partitioning. RSR was regressed against stream and basin features averaged per study unit. Results, LSR responded most strongly to variability in stream manganese concentration and RSR. Other predictors included stream discharge and iron concentration, soil organic matter content and fertilization, and proportions of open water, barren land and forest in the watershed. Variance partitioning revealed that RSR had the lowest independent contribution to explained variance in LSR. Multiple regressions identified average stream iron concentration as the most important predictor of RSR. Main conclusions, Local micronutrient concentration was the major predictor of LSR, followed by RSR. Since average micronutrient supply in the region was the chief determinant of RSR, it is proposed that micronutrients had both a direct effect on LSR and an indirect effect through RSR. The same argument is extended to watershed features with an impact on stream trophic status, because of their substantial contributions to the explained variance in both LSR and RSR. Considering that the major proportion of LSR variance explained by RSR originated from the covariance of RSR with stream and watershed properties, it is concluded that the LSR,RSR relationship was mediated by the local and regional environment. [source]

Diversity of Interactions: A Metric for Studies of Biodiversity

BIOTROPICA, Issue 3 2010
Lee A. Dyer
ABSTRACT Multitrophic interactions play key roles in the origin and maintenance of species diversity, and the study of these interactions has contributed to important theoretical advances in ecology and evolutionary biology. Nevertheless, most biodiversity inventories focus on static species lists, and prominent theories of diversity still ignore trophic interactions. The lack of a simple interaction metric that is analogous to species richness is one reason why diversity of interactions is not examined as a response or predictor variable in diversity studies. Using plant,herbivore,enemy trophic chains as an example, we develop a simple metric of diversity in which richness, diversity indices (e.g., Simpson's 1/D), and rarefaction diversity are calculated with links as the basic unit rather than species. Interactions include all two-link (herbivore,plant and enemy,herbivore) and three-link (enemy,herbivore,plant) chains found in a study unit. This metric is different from other indices, such as traditional diversity measures, connectivity and interaction diversity in food-web studies, and the diversity of interaction index in behavioral studies, and it is easier to compute. Using this approach to studying diversity provides novel insight into debates about neutrality and correlations between diversity, stability, productivity, and ecosystem services. Abstract in Spanish is available at http://www.blackwell-synergy.com/loi/btp [source]

Evaluation of NOC Measures in Home Care Nursing Practice

INTERNATIONAL JOURNAL OF NURSING TERMINOLOGIES AND CLASSIFICATION, Issue 2003
Gail M. Keenan
PURPOSE To evaluate the reliability, validity, usefulness, and sensitivity of 89 NOC outcomes in two Visiting Nurse Associations in Michigan. METHODS Of a total 190 NOC outcomes 89 were assigned for testing. Interrater reliability and criterion validity were assessed a total of 50 times per outcome (on 50 different patients) across the study units. The total number of times the reliability and validity were assessed for each of the 89 measures studied ranged from 5,45. Three RN research assistants (RNRAs) oversaw and participated in data collection with the help of 15 clinicians. Convenience sampling was used to identify subjects. A roster of outcomes to be studied was maintained and matched with patient conditions whenever possible until the quota of outcomes assigned had been evaluated. Clinicians and RNRAs independently rated the outcomes and indicators applicable to the patient. NANDA diagnoses, NIC interventions, and medical diagnoses were recorded. FINDINGS A total of 258 patients (mean age 62) enrolled; 60% were women, 23% were from minority groups, and 78% had no college degree. Thirty-six of the 89 NOC measures were designated "clinically useful." The 10 outcomes with the highest interrater reliability were Caregiver Home Care Readiness; Caregiver Stressors; Caregiving Endurance Potential; Infection Status; Mobility Level; Safety Status: Physical Injury; Self-Care: Activities of Daily Living; Self-Care: Bathing; Self-Care: Hygiene; and Wound Healing: Secondary Intention. Criterion measurement and repeated ratings provided evidence to support the validity and sensitivity of the NOC outcomes. Evidence also suggested that NOC label level ratings could be a feasible, reliable, and valid method of evaluating nursing outcomes under actual use. For some measures, adjustments in the scales and anchors are needed to enhance reliability. For others, it may be unrealistic to reliably score in one encounter, thus scoring should be deferred until the clinician has adequate knowledge of the patient. CONCLUSIONS Continued study and refinement that are coordinated and integrated systematically strongly recommended. Comprehensive study in an automated system with a controlled format will increase the efficiency of future studies. [source]

Effective assessment of use of sitters by nurses in inpatient care settings

JOURNAL OF ADVANCED NURSING, Issue 2 2008
Huey-Ming Tzeng
Abstract Title.,Effective assessment of use of sitters by nurses in inpatient care settings Aim., This paper is a report of the evaluation of the impact of adopting the Patient Attendant Assessment Tool (PAAT) on nurses' requests for sitters, use of restraints, and falls and fall injury rates. Background., Staffing should be the primary issue in eliminating risks of patient falls during hospital stays. Method., Data were collected in two acute adult medical units of a Michigan hospital from August 2005 to February 2007. Data from three sources were merged for analyses: (1) study units' monthly reports; (2) quarterly reports of the National Database of Nursing Quality Indicators and (3) PAAT reports collected from October 2006 to February 2007. The primary outcome variables were the use of sitters, number of restraints ordered and fall and fall injury rates. Independent t -tests and correlation analyses were used for data analyses. The data before and after adopting this tool were compared using independent t -tests. Findings., The PAAT helped improve the fill/request rates for sitters. The use of soft limb holders decreased after adoption of this tool. The results also showed that if the number of sitter requests was higher, the total number of restraints would be lower but the total fall rate would be higher. Conclusion., Hospitals should include a tool similar to the PAAT in guidelines related to provision of constant observation or use of sitters. Further investigations of the optimum combination of staffing patterns and infrastructure are needed to promote safer hospital stays. [source]