79 research outputs found
Dispersal Behavior and Connectivity of Red-cockaded Woodpeckers in the North Carolina Sandhills
Human activities are degrading natural ecosystems globally, thus eroding biological diversity and reducing wildlife populations. One prominent example is the Red-cockaded woodpecker (Picoides borealis) which is a federally endangered, cooperative breeding species endemic to highly-fragmented longleaf pine (Pinus palustris) forests in the southeastern United States. The persistence of P. borealis is dependent upon managing longleaf pine forests to facilitate prospecting and dispersal movements and thus connecting populations. My overall research objective was to interrelate spatial environmental data and animal movement behaviors in order to evaluate P. borealis habitat connectivity. First, I developed a novel method to empirically estimate and validate landscape resistance surfaces using mark-recapture and radio-telemetry data. I then applied this method to determine how prospecting movements were influenced by both environmental and conspecific cues during forays. The detail prospecting and dispersal data was then combined with detailed data on forest structure to estimate habitat connectivity across the landscape. Finally, I evaluate if P. borealis connectivity is positively impacted by private landowners involvement in a voluntary incentive-based agreement. My results illustrated with an empirically-derived resistance surface that P. borealis are influenced by subtle changes in vegetation structure and land-use activities. The resistance surface successfully predicted most of the short-distance dispersal events. In addition, prospecting individuals' are cueing into environmental characteristics between breeding sites and complex social dynamics at potential breeding sites. When the network model was correlated with observed dispersal events, the abrupt transition from highly connected to disconnected territories provides insight into habitat connectivity within and between habitat patches. This approach showed that highly connected territories reside within managed areas of continuous forest but territories on private properties are isolated from managed lands and each other by agriculture or development. However, voluntary incentive-based conservation programs on private land are increasing the connectivity of P. borealis populations by managing and restoring habitat on private property.Doctor of Philosoph
Use of Prosody and Information Structure in High Functioning Adults with Autism in Relation to Language Ability
Abnormal prosody is a striking feature of the speech of those with Autism spectrum disorder (ASD), but previous reports suggest large variability among those with ASD. Here we show that part of this heterogeneity can be explained by level of language functioning. We recorded semi-spontaneous but controlled conversations in adults with and without ASD and measured features related to pitch and duration to determine (1) general use of prosodic features, (2) prosodic use in relation to marking information structure, specifically, the emphasis of new information in a sentence (focus) as opposed to information already given in the conversational context (topic), and (3) the relation between prosodic use and level of language functioning. We found that, compared to typical adults, those with ASD with high language functioning generally used a larger pitch range than controls but did not mark information structure, whereas those with moderate language functioning generally used a smaller pitch range than controls but marked information structure appropriately to a large extent. Both impaired general prosodic use and impaired marking of information structure would be expected to seriously impact social communication and thereby lead to increased difficulty in personal domains, such as making and keeping friendships, and in professional domains, such as competing for employment opportunities
Experimental Passage of St. Louis Encephalitis Virus In Vivo in Mosquitoes and Chickens Reveals Evolutionarily Significant Virus Characteristics
St. Louis encephalitis virus (SLEV; Flaviviridae, flavivirus) was the major cause of epidemic flaviviral encephalitis in the U.S. prior to the introduction of West Nile virus (WNV) in 1999. However, outbreaks of SLEV have been significantly more limited then WNV in terms of levels of activity and geographic dispersal. One possible explanation for these variable levels of activity is that differences in the potential for each virus to adapt to its host cycle exist. The need for arboviruses to replicate in disparate hosts is thought to result in constraints on both evolution and host-specific adaptation. If cycling is the cause of genetic stability observed in nature and arboviruses lack host specialization, then sequential passage should result in both the accumulation of mutations and specialized viruses better suited for replication in that host. Previous studies suggest that WNV and SLEV differ in capacity for both genetic change and host specialization, and in the costs each accrues from specializing. In an attempt to clarify how selective pressures contribute to epidemiological patterns of WNV and SLEV, we evaluated mutant spectra size, consensus genetic change, and phenotypic changes for SLEV in vivo following 20 sequential passages via inoculation in either Culex pipiens mosquitoes or chickens. Results demonstrate that the capacity for genetic change is large for SLEV and that the size of the mutant spectrum is host-dependent using our passage methodology. Despite this, a general lack of consensus change resulted from passage in either host, a result that contrasts with the idea that constraints on evolution in nature result from host cycling alone. Results also suggest that a high level of adaptation to both hosts already exists, despite host cycling. A strain significantly more infectious in chickens did emerge from one lineage of chicken passage, yet other lineages and all mosquito passage strains did not display measurable host-specific fitness gains. In addition, increased infectivity in chickens did not decrease infectivity in mosquitoes, which further contrasts the concept of fitness trade-offs for arboviruses
Physical activity and depression in adolescents: cross-sectional findings from the ALSPAC cohort
Purpose: Few studies have examined the association between physical activity (PA), measured objectively, and adolescent depressive symptoms. The aim of this study was to determine whether there is an association between objective measures of PA (total PA and time spent in moderate and vigorous PA (MVPA)) and adolescent depressive symptoms.
Methods: Data on 2,951 adolescents participating in ALSPAC were used. Depressive symptoms were measured using the self-report Mood and Feelings Questionnaire (MFQ) (short version). Measures of PA were based on accelerometry. The association between PA and MFQ scores was modelled using ordinal regression. Results: Adolescents who were more physically active (total PA or minutes of MVPA) had a reduced odds of depressive symptoms [ORadj total PA (tertiles): medium 0.82 (95% CI: 0.69, 0.97); high 0.69 (95% CI: 0.57, 0.83)]; ORadj per 15 min MVPA: 0.92 (95% CI: 0.86, 0.98). In a multivariable model including both total PA and the percentage of time spent in MVPA, total PA was associated with depressive symptoms (ORadj total PA (tertiles): medium 0.82 (95% CI: 0.70, 0.98); high 0.70 (95% CI: 0.58, 0.85) but the percentage of time spent in MVPA was not independently associated with depressive symptoms [ORadj MVPA (tertiles) medium 1.05 (95% CI: 0.88, 1.24), high 0.91 (95% CI: 0.77, 1.09)]. Conclusions: The total amount of PA undertaken was associated with adolescent depressive symptoms, but the amount of time spent in MVPA, once total PA was accounted for, was not. If confirmed in longitudinal studies and randomised controlled trials, this would have important implications for public health messages.Nicola J. Wiles, Anne M. Haase, Debbie A. Lawlor, Andy Ness, Glyn Lewi
Adjunctive rifampicin for Staphylococcus aureus bacteraemia (ARREST): a multicentre, randomised, double-blind, placebo-controlled trial.
BACKGROUND: Staphylococcus aureus bacteraemia is a common cause of severe community-acquired and hospital-acquired infection worldwide. We tested the hypothesis that adjunctive rifampicin would reduce bacteriologically confirmed treatment failure or disease recurrence, or death, by enhancing early S aureus killing, sterilising infected foci and blood faster, and reducing risks of dissemination and metastatic infection. METHODS: In this multicentre, randomised, double-blind, placebo-controlled trial, adults (≥18 years) with S aureus bacteraemia who had received ≤96 h of active antibiotic therapy were recruited from 29 UK hospitals. Patients were randomly assigned (1:1) via a computer-generated sequential randomisation list to receive 2 weeks of adjunctive rifampicin (600 mg or 900 mg per day according to weight, oral or intravenous) versus identical placebo, together with standard antibiotic therapy. Randomisation was stratified by centre. Patients, investigators, and those caring for the patients were masked to group allocation. The primary outcome was time to bacteriologically confirmed treatment failure or disease recurrence, or death (all-cause), from randomisation to 12 weeks, adjudicated by an independent review committee masked to the treatment. Analysis was intention to treat. This trial was registered, number ISRCTN37666216, and is closed to new participants. FINDINGS: Between Dec 10, 2012, and Oct 25, 2016, 758 eligible participants were randomly assigned: 370 to rifampicin and 388 to placebo. 485 (64%) participants had community-acquired S aureus infections, and 132 (17%) had nosocomial S aureus infections. 47 (6%) had meticillin-resistant infections. 301 (40%) participants had an initial deep infection focus. Standard antibiotics were given for 29 (IQR 18-45) days; 619 (82%) participants received flucloxacillin. By week 12, 62 (17%) of participants who received rifampicin versus 71 (18%) who received placebo experienced treatment failure or disease recurrence, or died (absolute risk difference -1·4%, 95% CI -7·0 to 4·3; hazard ratio 0·96, 0·68-1·35, p=0·81). From randomisation to 12 weeks, no evidence of differences in serious (p=0·17) or grade 3-4 (p=0·36) adverse events were observed; however, 63 (17%) participants in the rifampicin group versus 39 (10%) in the placebo group had antibiotic or trial drug-modifying adverse events (p=0·004), and 24 (6%) versus six (2%) had drug interactions (p=0·0005). INTERPRETATION: Adjunctive rifampicin provided no overall benefit over standard antibiotic therapy in adults with S aureus bacteraemia. FUNDING: UK National Institute for Health Research Health Technology Assessment
Avoiding ecosystem and social impacts of hydropower, wind, and solar in Southern Africas low-carbon electricity system.
Fatalism and its role in post cardiac surgery depression
Depression following cardiac surgery is more common than appreciated and can adversely impact length of stay, recovery, and quality of life. The purpose of this study was to identify those at increased risk of developing post-operative depression and to intervene early to decrease the mortality and morbidity associated with post-operative depression. This study prospectively analyzed various patient characteristics, socio-economic factors, and fatalism to determine their relationship to post-operative depression. If a correlation was identified, then pre-operative intervention could be initiated to mitigate the adverse effects of depression on recovery. Consecutive patients scheduled for coronary bypass or valve surgery were screened for inclusion in the study. Patients under the age of 40, those with pre-existing depression, and patients needing reoperation were excluded. One hundred twenty-five patients who met criteria were followed over a 12-week period. Baseline data relating to heart surgery (Euroscore), socio-economic demographics, depression score (PHQ9), and a fatalism scale were collected. Follow-up assessments for depression occurred at 6 weeks and at 12 weeks post-surgery. Data were collected by chart review and direct face-to-face interviews, and were analyzed utilizing SAS software. Eighty-four men and 41 women met the inclusion criteria. One hundred fourteen (91%) completed follow-up at 6 weeks, and 105 (84%) completed the follow-up at 12 weeks. The mean fatalism score was 49.4 (22-88), and the mean depression score was 4.0(0-11). Fatalism, Euroscore, baseline PHQ-9 score, gender, race, marital status, education level, church membership, and diabetes explained 22% of the variability in PHQ-9 scores at both 6 and 12 weeks. However, this was not significant (p=> 0.05). Fatalism was found to be associated with depression, but socio-demographic factors explained more variability in depression at 6 weeks and 12 weeks. Further studies to identify other determinants of postoperative depression are warranted. The results suggest that pre-operative interventions to limit subsequent depression should be explored
Energy Sprawl Is the Largest Driver of Land Use Change in United States
<div><p>Energy production in the United States for domestic use and export is predicted to rise 27% by 2040. We quantify projected energy sprawl (new land required for energy production) in the United States through 2040. Over 200,000 km<sup>2</sup> of additional land area will be directly impacted by energy development. When spacing requirements are included, over 800,000 km<sup>2</sup> of additional land area will be affected by energy development, an area greater than the size of Texas. This pace of development in the United States is more than double the historic rate of urban and residential development, which has been the greatest driver of conversion in the United States since 1970, and is higher than projections for future land use change from residential development or agriculture. New technology now places 1.3 million km<sup>2</sup> that had not previously experienced oil and gas development at risk of development for unconventional oil and gas. Renewable energy production can be sustained indefinitely on the same land base, while extractive energy must continually drill and mine new areas to sustain production. We calculated the number of years required for fossil energy production to expand to cover the same area as renewables, if both were to produce the same amount of energy each year. The land required for coal production would grow to equal or exceed that of wind, solar and geothermal energy within 2–31 years. In contrast, it would take hundreds of years for oil production to have the same energy sprawl as biofuels. Meeting energy demands while conserving nature will require increased energy conservation, in addition to distributed renewable energy and appropriate siting and mitigation.</p></div
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