Choice of biodiversity index drives optimal fire management decisions.

Preservation of biodiversity is a central goal of conservation management, yet the conditions that promote persistence may differ for the species in the community. For systems subject to stochastic disturbances such as fire, understanding which management practices promote persistence for all species in a community is complex. Before deciding on the best course of action, an objective must be specified. Yet an overarching goal of species persistence can be specified into a measureable objective many different ways. We investigated four alternative management objectives for maximizing species persistence that use common biodiversity indices: (1) attaining the minimally acceptable mix of successional vegetation states to support species' relative abundances, (2) maximizing the arithmetic mean abundance of species, (3) maximizing the geometric mean abundance of species, and (4) minimizing the average extinction risk of species. We used stochastic dynamic programming to model successional changes in vegetation in the presence of both planned and unplanned fires, and utilize an extensive data set on the occurrence of birds, reptiles, and small mammals in different successional states in semiarid Australia. We investigated the influence the choice of objective function and taxonomic focus has on the optimal fire management recommendations. We also evaluated a recent hazard reduction policy to annually burn a fixed amount of the landscape and compare results to the optimal solution. The optimal management strategy to maximize species persistence over a 100-year period is predominantly to minimize wildfires. This is because the majority of species are more likely to occur in intermediate, and late successional vegetation. However the optimal solution showed sensitivity to the objective and the species included in the analysis. These results highlight the need for careful consideration when specifying an objective to represent overarching conservation goals. Using the extinction risk objective, we show that a policy to annually burn 5% of the landscape could increase the average probability of extinction for the modelled species by 7% over the next 100 years compared to the optimal management scenario.

Species distributions and area relationships.

The well-known species-area relationship is one of many scaling laws, or allometries, in ecology and biology that have received much attention over the years. We present a new derivation of this relationship based on Yule׳s theory of evolution of species. Using definitions of mutation rates, our analysis yields species-area exponents that are in close agreement with previously observed values.

Effects of exercise and lifestyle modification on fitness, insulin resistance, skeletal muscle oxidative phosphorylation and intramyocellular lipid content in obese children and adolescents.

BACKGROUND: Obesity is associated with poor fitness and adverse metabolic consequences in children. OBJECTIVE: To investigate how exercise and lifestyle modification may improve fitness and insulin sensitivity in this population. DESIGN AND SUBJECTS: Randomized controlled trial, 21 obese (body mass index ≥ 95% percentile) subjects, ages 10 to 17 years. METHODS: Subjects were given standardized healthful lifestyle advice for 8 weeks. In addition, they were randomized to an in-home supervised exercise intervention (n = 10) or control group (n = 11). MEASUREMENTS: Fasting laboratory studies (insulin, glucose, lipid profile) and assessments of fitness, body composition, skeletal muscle oxidative phosphorylation and intramyocellular lipid content (IMCL), were performed at baseline and study completion. RESULTS: Subjects were 13.0 ± 1.9 (standard deviation) years old, 72% female and 44% non-white. Exercise improved fitness (P = 0.03) and power (P = 0.01), and increased IMCL (P = 0.02). HOMA-IR decreased among all subjects in response to lifestyle modification advice (P = 0.01), regardless of exercise training assignment. In univariate analysis in all subjects, change in cardiovascular fitness was associated with change in HOMA-IR. In exploratory analyses, increased IMCL was associated with greater resting energy expenditure (r = 0.78, P = 0.005) and a decrease in fasting respiratory quotient (r = -0.70, P = 0.02) (n = 11). CONCLUSIONS: Change in fitness was found to be related to change in insulin resistance in response to lifestyle modification and exercise in obese children. IMCL increased with exercise in these obese children, which may reflect greater muscle lipid oxidative capacity.

Inferring extinction risks from sighting records.

Estimating the probability that a species is extinct based on historical sighting records is important when deciding how much effort and money to invest in conservation policies. The framework we offer is more general than others in the literature to date. Our formulation allows for definite and uncertain observations, and thus better accommodates the realities of sighting record quality. Typically, the probability of observing a species given it is extant/extinct is challenging to define, especially when the possibility of a false observation is included. As such, we assume that observation probabilities derive from a representative probability density function. We incorporate this randomness in two different ways ("quenched" versus "annealed") using a framework that is equivalent to a Bayes formulation. The two methods can lead to significantly different estimates for extinction. In the case of definite sightings only, we provide an explicit deterministic calculation (in which observation probabilities are point estimates). Furthermore, our formulation replicates previous work in certain limiting cases. In the case of uncertain sightings, we allow for the possibility of several independent observational types (specimen, photographs, etc.). The method is applied to the Caribbean monk seal, Monachus tropicalis (which has only definite sightings), and synthetic data, with uncertain sightings.

Circulating branched-chain amino acid concentrations are associated with obesity and future insulin resistance in children and adolescents.

UNLABELLED: What is already known about this subject Circulating concentrations of branched-chain amino acids (BCAAs) can affect carbohydrate metabolism in skeletal muscle, and therefore may alter insulin sensitivity. BCAAs are elevated in adults with diet-induced obesity, and are associated with their future risk of type 2 diabetes even after accounting for baseline clinical risk factors. What this study adds Increased concentrations of BCAAs are already present in young obese children and their metabolomic profiles are consistent with increased BCAA catabolism. Elevations in BCAAs in children are positively associated with insulin resistance measured 18 months later, independent of their initial body mass index. BACKGROUND: Branched-chain amino acid (BCAA) concentrations are elevated in response to overnutrition, and can affect both insulin sensitivity and secretion. Alterations in their metabolism may therefore play a role in the early pathogenesis of type 2 diabetes in overweight children. OBJECTIVE: To determine whether paediatric obesity is associated with elevations in fasting circulating concentrations of BCAAs (isoleucine, leucine and valine), and whether these elevations predict future insulin resistance. METHODS: Sixty-nine healthy subjects, ages 8-18 years, were enrolled as a cross-sectional cohort. A subset of subjects who were pre- or early-pubertal, ages 8-13 years, were enrolled in a prospective longitudinal cohort for 18 months (n = 17 with complete data). RESULTS: Elevations in the concentrations of BCAAs were significantly associated with body mass index (BMI) Z-score (Spearman's Rho 0.27, P = 0.03) in the cross-sectional cohort. In the subset of subjects that followed longitudinally, baseline BCAA concentrations were positively associated with homeostasis model assessment for insulin resistance measured 18 months later after controlling for baseline clinical factors including BMI Z-score, sex and pubertal stage (P = 0.046). CONCLUSIONS: Elevations in the concentrations of circulating BCAAs are significantly associated with obesity in children and adolescents, and may independently predict future insulin resistance.

Current transport across the pentacene/CVD-grown graphene interface for diode applications.

We investigate the electronic transport properties across the pentacene/graphene interface. Current transport across the pentacene/graphene interface is found to be strikingly different from transport across pentacene/HOPG and pentacene/Cu interfaces. At low voltages, diodes using graphene as a bottom electrode display Poole­Frenkel emission, while diodes with HOPG and Cu electrodes are dominated by thermionic emission. At high voltages conduction is dominated by Poole­Frenkel emission for all three junctions. We propose that current across these interfaces can be accurately modeled by a combination of thermionic and Poole­Frenkel emission. Results presented not only suggest that graphene provides low resistive contacts to pentacene where a flat-laying orientation of pentacene and transparent metal electrodes are desired but also provides further understanding of the physics at the organic semiconductor/graphene interface.

Low-voltage, low-power, organic light-emitting transistors for active matrix displays.

Intrinsic nonuniformity in the polycrystalline-silicon backplane transistors of active matrix organic light-emitting diode displays severely limits display size. Organic semiconductors might provide an alternative, but their mobility remains too low to be useful in the conventional thin-film transistor design. Here we demonstrate an organic channel light-emitting transistor operating at low voltage, with low power dissipation, and high aperture ratio, in the three primary colors. The high level of performance is enabled by a single-wall carbon nanotube network source electrode that permits integration of the drive transistor and the light emitter into an efficient single stacked device. The performance demonstrated is comparable to that of polycrystalline-silicon backplane transistor-driven display pixels.

Multiwall nanotubes can be stronger than single wall nanotubes and implications for nanocomposite design.

Molecular dynamics modeling shows that multiwall carbon nanotubes (MWCNTs) with sp;{3} interwall bonding have strengths exceeding those of single-wall carbon nanotubes (SWCNTs) containing the same size initial intrawall defect, and are far less sensitive to defect size. Thus, although processing methods used to increase interwall coupling also create intrawall defects, analyses here show that the strengthening effects and enhanced load transfer compensate for the creation of defects and make MWCNTs with interwall bonding preferable to SWCNTs as mechanical reinforcements in composites. These results are consistent with new experimental data and suggest a new design methodology for CNT-based composites.

Adolescent depression: important facts that matter.

PURPOSE: To determine if there are differences in adolescent depression using variables of age, gender, smoking, and alcohol use. METHODS: A comparative, descriptive survey design was used. The adolescents (N = 217) completed either the Beck Depression Inventory or the Children's Depression Inventory and a demographic questionnaire. FINDINGS: The 15- to 16-year-olds (p = .016), females (p = .003), and smokers (p = .001) scored significantly higher than the 12- to 14-year-olds on depression. The 15- to 16-year-olds who used alcohol were found to be twice as depressed as the nonusers (p = .002). No significant differences were found in the 17- to 19-year-old age group. CONCLUSIONS: This study confirmed depression increased with age, in females, and with smokers. Nurses are in a unique position to provide interventions to promote healthy lifestyles and reduce the likelihood of depression and alcohol and nicotine abuse in adolescents.

Childhood anger: so common, yet so misunderstood.

PURPOSE: To review findings of recent research studies on anger in children and adolescents, the outcomes of mishandled anger and interventions to promote appropriate anger management. SOURCE: Published literature. CONCLUSIONS: Anger may be a healthy or unhealthy response in children experiencing small frustrations or great injustices. Research findings vary and there is a need to clearly define anger and the correlates of anger in children and adolescents. In addition, there are limited studies on anger management strategies and their effectiveness that would assist healthcare professionals.

Keeping current: ten important information resources to help rehabilitation nurses.

Rehabilitation nurses have a professional responsibility to provide the most current and informed client care possible. As a result, they must keep up with the emerging healthcare delivery system of the 21st century. This article describes how nurses can get access to and use 10 information resources--namely, journals, books, pamphlets, indexes and on-line databases, conferences, continuing education, professional organizations, standards of practice of interest to nurses in rehabilitation nursing, and networking.

Perioperative nurses' guide to the library.

Nurses have a professional responsibility, both morally and ethically, to provide the most current and informed patient care possible. Nurses should maintain competence in nursing, exercise informed judgment, participate in activities that contribute to the ongoing development of their profession's body of knowledge, and participate in their profession's efforts to implement and improve standards of nursing care. Nurses should stay current with new information and share this information with coworkers to help disseminate new knowledge. Such practices help advance both the body of knowledge for perioperative nursing and the profession of nursing. Nurses are encouraged to make at least two visits each year to the library. During this time, they can take the opportunity to review current periodicals, recent publications, do a CINAHL search, and browse the Internet. Nurses need to be familiar with library resources, so go to the library. Share your findings with colleagues and students. Acquire the information-seeking skills that will best serve you and your patients in the twenty-first century.

Preterm infants and STRESS: a tool for the neonatal nurse.

Preterm infants are not physiologically or developmentally prepared for life outside the supportive environment of the mother's womb. Their response to stimuli is often immature and disorganized rather than adaptive. The Roy Adaptation Model's theory of an adaptive person may provide a framework for nurses to assess, plan, and evaluate nursing care for fragile preterm infants. The article examines actual and potential stressors of the premature infant; describes commonly observed disorganized, ineffective responses; and proposes a clinical tool (the STRESS tool: signs of stress, touch interventions, reduction of pain, environmental considerations, state, and stability) that nurses can use when caring for medically fragile infants.

Responding to Healthy People 2000: depression in our youth, common yet misunderstood.

Pediatric health care providers are concerned with the physical health, growth, and development of youth. The U.S. Public Health Service has recommended that children's mental status be reviewed during routine assessments, and the promotion of mental health is one of the priorities set by Healthy People 2000. Pediatric nurses must be able to assess mental status, including depression, in children and adolescents, and to identify pathology early. This paper presents an overview of depression, historical perspectives, risk factors, a developmental approach to assessment, common treatment regimens, and nursing implications for this mental health concern in children and adolescents.

Multi-species risk analysis, species evaluation and biodiversity conservation.

The multi-species conservation approaches starting from Vane-Wright et al. (1991) search for a biologically valid basis to evaluate biodiversity. Such evaluations can be used to optimize reserve boundaries so reserves contain a high level of biodiversity. However, these optimization procedures do not minimize the future loss of biodiversity. We provide a method that can be used to minimize the loss of biodiversity. The method integrates an evolutionary species evaluation with an ecological multi-species risk analysis to estimate the expected loss of phylogenetic diversity. A minimization of this loss will optimize the preservation of phylogenetic diversity.

Obstetric care and cesarean birth rates: a program to monitor quality of care.

OBJECTIVE: To study the quality of obstetric care in relation to rising cesarean rates, a Task Force was formed in New York state by the Department of Health and ACOG District II. The Task Force also included the Organization of Obstetric, Gynecologic, and Neonatal Nurses and the Hospital Association of New York State. The goals were to enhance hospitals' in-house review processes, standardize terminology, and improve the quality of care. A premise of the program was that if quality of care improved, cesarean rates would fall. METHODS: A Dictionary of Terms was developed to standardize clinical and diagnostic terminology. A two-tiered review process was instituted, using internal and external hospital reviews. A format for in-house review of obstetric care was developed and recommended to hospitals. External reviews were conducted at 24 hospitals during 1989-1990. Review teams, composed of obstetrician-gynecologists and obstetric nurses in active obstetric practice, assessed obstetric facilities, staffing, medical care, and the in-house review process. Contacts continued with the hospitals after site visits to follow up on implementation of recommendations. General recommendations to improve care, based on the overall program experience, were distributed to hospitals and physicians as part of educational efforts to improve quality of care. RESULTS: The state cesarean rate reversed. Statistics for 1989 and 1990 showed a stronger downward trend in reviewed hospitals than in non-reviewed hospitals. A survey of reviewed hospitals reported a positive response to the review process. CONCLUSION: A successful quality assurance program can be jointly developed by a state regulatory agency and a medical specialty society.

Illness in hemodialysis patients after exposure to chloramine contaminated dialysate.

In September 1987, patients at an outpatient dialysis center were exposed to chloramine contaminated dialysate when the carbon filter in a recently modified water treatment system failed. Forty-one patients required transfusion to treat the resultant hemolytic anemia. Epidemiologic investigation demonstrated that the mortality rate among dialysis center patients increased during the 5 months after chloramine exposure when compared with the 12 months before chloramine exposure, but no deaths could be attributed to the exposure. Chloramine is commonly used as a disinfectant in municipal water supplies, and has previously been reported to cause hemolytic anemia in patients undergoing dialysis. Hemodialysis centers in cities that use chloramine in water supplies must design water treatment systems with adequate means for removing chloramine and must monitor processed water closely to ensure that chloramine contamination does not occur. Dialysis centers that make changes in their water processing systems should evaluate all components of the system before changes are made, and must ensure that after modifications are made, processed water meets the standards set by the Association for Advancement of Medical Instrumentation.

Epidermolysis bullosa and aplasia cutis.

Recessive dystrophic epidermolysis bullosa with aplasia cutis occurring in a male infant is described. The association of these two rare conditions is reviewed. Reports of the concurrence of large areas of congenital absence of skin, particularly on the lower limbs, in patients with several different types of epidermolysis bullosa suggest that areas of congenital absence of skin in these patients are an initial manifestation of the bullous disease rather than a distinctive entity.