191 research outputs found
Should Maine Develop a More Comprehensive Approach to Invasive Species Management
Currently the state of invasive species management in Maine seems to be very siloed with little interagency or organizational coordination or prioritization. To assess the current situation, a survey was created and sent to approximately 600 recipients (Appendix 1). Recipients included representatives from state, federal, non-profit and private organizations that are known actors in the invasive species community in Maine. The survey was also posted on the Maine Invasive Species Network listserv.12 There were 197 respondents which provides a significant but incomplete sample of the management efforts currently taking place in Maine. Respondents represented all potential affiliations involved in invasive species management (Figure 3). These respondents indicated they were concerned about all regions in Maine (Figure 4). The greatest concern is predictably for the most developed regions with over half concerned about Cumberland and York Counties (53%) and the least concern for Aroostook County (18%) (Figure 4). Additionally, respondents listed management of or concerns about species in all the major taxa groups in terrestrial, freshwater, and marine environment
The Predictive Relationship Between Psychological Capital and Academic Burnout in Postgraduate Students
Purpose: The purpose of this quantitative correlational study was to determine if, or to what extent, the composite and sub-composite categories of Psychological Capital (PsyCap) predict academic burnout in American postgraduate health science students at a university in the Southeastern United States. Methods: The variables of the study were measured by the Psychological Capital Questionnaire (PCQ-24) and the Maslach Burnout Inventory-Student Survey (MBI-SS). A convenience sampling method was used to collect data from the target population, which included a final sample of 90 health science postgraduate students. Results: A simple linear regression analysis revealed that PsyCap was a significant and negative predictor of academic burnout (F(1,88) = 12.00, p \u3c .001, R2 = 0.12; B = -0.28, t(88) = -3.46, p \u3c .001). Additionally, multiple linear regression analysis revealed that only one sub-category of PsyCap, labeled as Optimism, was a significant and negative predictor of academic burnout (F(4,85) = 5.17, p \u3c .001, R2= 0.20; B = -0.90, t(85) = -3.17, p = .002). Conclusion: The findings may be used by higher education instructors, advisors, and administrators in the United States to adopt policies, practices, programs, student advising, and student mentorship that foster PsyCap and Optimism development in students, which may mitigate the risks and consequences of academic burnout
Color matches in diseased eyes with good acuity: detection of deficits in cone optical density and in chromatic discrimination
Reduced foveal cone optical density in diseased eyes with normal acuity can affect color matches. Using field diameters of 1 ± , 2 ± , 4 ± , and 8 ± , we measured mean color-match midpoints and match widths in patients who had good acuity and who exhibited three categories of eye disease: hereditary macular degeneration (n 12), retinitis pigmentosa (n 19), and glaucoma (n 18). Results were compared with those for normal observers of comparable ages. Mean color-match midpoints were abnormal only for the population with hereditary macular degeneration, indicating a reduction in cone optical density in the central 4 ± . Mean color-match widths were enlarged for both hereditary macular degeneration and retinitis pigmentosa, a result consistent with a reduction in the number of foveal cones
Herschel observations of interstellar chloronium
Using the Herschel Space Observatory's Heterodyne Instrument for the
Far-Infrared (HIFI), we have observed para-chloronium (H2Cl+) toward six
sources in the Galaxy. We detected interstellar chloronium absorption in
foreground molecular clouds along the sight-lines to the bright submillimeter
continuum sources Sgr A (+50 km/s cloud) and W31C. Both the para-H2-35Cl+ and
para-H2-37Cl+ isotopologues were detected, through observations of their
1(11)-0(00) transitions at rest frequencies of 485.42 and 484.23 GHz,
respectively. For an assumed ortho-to-para ratio of 3, the observed optical
depths imply that chloronium accounts for ~ 4 - 12% of chlorine nuclei in the
gas phase. We detected interstellar chloronium emission from two sources in the
Orion Molecular Cloud 1: the Orion Bar photodissociation region and the Orion
South condensation. For an assumed ortho-to-para ratio of 3 for chloronium, the
observed emission line fluxes imply total beam-averaged column densities of ~
2.0E+13 cm-2 and ~ 1.2E+13 cm-2, respectively, for chloronium in these two
sources. We obtained upper limits on the para-H2-35Cl+ line strengths toward H2
Peak 1 in the Orion Molecular cloud and toward the massive young star AFGL
2591. The chloronium abundances inferred in this study are typically at least a
factor ~10 larger than the predictions of steady-state theoretical models for
the chemistry of interstellar molecules containing chlorine. Several
explanations for this discrepancy were investigated, but none has proven
satisfactory, and thus the large observed abundances of chloronium remain
puzzling.Comment: Accepted for publication in the Astrophysical Journa
Structural properties of discs and bulges of early-type galaxies
We have used the EFAR sample of galaxies to study the light distributions of
early-type galaxies. We decompose the 2D light distribution of the galaxies in
a flattened spheroidal component with a Sersic radial light profile and an
inclined disc component with an exponential light profile. We show that the
brightest, bulge dominated elliptical galaxies have a fairly broad distribution
in the Sersic profile shape parameter n_B, with a median of about 3.7 and a
sigma of ~0.9. Other galaxies have smaller n_B values, meaning that spheroids
are in general less concentrated than the n_B=4 de Vaucouleurs-law profile.
The results of our light decompositions are robust, even though without
kinematic information we cannot prove that the spheroids and discs are really
pressure- and rotation-supported stellar systems. If we assume that the
detected spheroids and discs are indeed separate components, we can draw the
following conclusions: 1) the spheroid and disc scale sizes are correlated; 2)
bulge-to-total luminosity ratios, bulge effective radii, and bulge n_B values
are all positively correlated; 3) the bivariate space density distribution of
elliptical galaxies in the (luminosity, scale size)-plane is well described by
a Schechter luminosity function in and a log-normal scale-size distribution at
a given luminosity; 4) at the brightest luminosities, the scale size
distribution of elliptical galaxies is similar to those of bright spiral
galaxies; at fainter luminosities the elliptical scale size distribution peaks
at distinctly smaller sizes than the spiral galaxy distribution; and 5) bulge
components of early-type galaxies are typically a factor 1.5 to 2.5 smaller
than the disks of spiral galaxies, while disc components of early-type galaxies
are typically twice as large as the discs of spiral galaxies. [abridged]Comment: 16 pages, 18 figures. Accepted for publication in the MNRA
Safety Assessment of Docosahexaenoic Acid in X-Linked Retinitis Pigmentosa: The 4-Year DHAX Trial
Citation: Hughbanks-Wheaton DK, Birch DG, Fish GE, et al. Safety assessment of docosahexaenoic acid in X-linked retinitis pigmentosa: the 4-year DHAX trial. Invest Ophthalmol Vis Sci. 2014;55:4958-4966. DOI: 10.1167/iovs.14-14437 PURPOSE. Docosahexaenoic acid (DHA) continues to be evaluated and recommended as treatment and prophylaxis for various diseases. We recently assessed efficacy of high-dose DHA supplementation to slow vision loss in patients with X-linked retinitis pigmentosa (XLRP) in a randomized clinical trial. Because DHA is a highly unsaturated fatty acid, it could serve as a target for free-radical induced oxidation, resulting in increased oxidative stress. Biosafety was monitored during the 4-year trial to determine whether DHA supplementation was associated with identifiable risks. METHODS. Males (n ¼ 78; 7-31 years) meeting entry criteria were enrolled. The modified intent-to-treat cohort (DHA ¼ 33; placebo ¼ 27) adhered to the protocol ‡ 1 year. Participants were randomized to an oral dose of 30 mg/kg/d DHA or placebo plus a daily multivitamin. Comprehensive metabolic analyses were assessed for group differences. Treatment-emergent adverse events including blood chemistry metabolites were recorded. RESULTS. By year 4, supplementation elevated plasma and red blood cell-DHA 4.4-and 3.6-fold, respectively, compared with the placebo group (P < 0.00001). Over the trial duration, no significant differences between DHA and placebo groups were found for vitamin A, vitamin E, platelet aggregation, antioxidant activity, lipoprotein cholesterol, or oxidized LDL levels (all P > 0.14). Adverse events were transient and not considered severe (e.g., gastrointestinal [GI] irritability, blood chemistry alterations). One participant was unable to tolerate persistent GI discomfort. CONCLUSIONS. Long-term, high-dose DHA supplementation to patients with XLRP was associated with limited safety risks in this 4-year trial. Nevertheless, GI symptoms should be monitored in all patients taking high dose DHA especially those with personal or family history of GI disturbances. (ClinicalTrials.gov number, NCT00100230.) Keywords: biosafety, fatty acids, adverse events R etinitis pigmentosa (RP) is a retinal degenerative disease characterized by night blindness and visual field constriction 1 with four underlying inheritance patterns. The X-linked form of RP (XLRP) is among the most severe with night blindness often detectable by age 5 years 2-4 and legal blindness by the second or third decade. Gene defects are known to cause retinal degeneration, yet factors such as environment, diet, stress, and/or metabolism may modify disease severity. Many patients with RP have lower plasma and red blood cell (RBC) levels of the n3 polyunsaturated fatty acid docosahexaenoic acid (DHA; 22:6n3) than normally-sighted controls. 5 Blood DHA was significantly correlated with age-adjusted ERG responses in XLRP such that patients with lower RBC-DHA tended to have lower ERG amplitudes. 6 These findings were similarly documented in approximately 70% of female XLRP carriers (Hoffman DR, et al. IOVS 1998;39:ARVO Abstract 725). A reduction in DHA biosynthesis was demonstrated in XLRP using stable isotopes to assess in vivo metabolism 7 suggesting that downregulation of hepatic D 5 desaturase may contribute to subnormal blood DHA levels. Thus, daily supplementation with DHA may bypass any decrease in DHA biosynthesis. Docosahexaenoic acid comprises 1% to 5% of membrane fatty acids in most human tissues; however, it is the most abundant fatty acid in the retina. 8 This n3 fatty acid can increase membrane fluidity and modify the mobility of vital proteins and activities of retinal enzymes, 9,10 promote photoreceptor differentiation, 11 and antiapoptotic activity. 12 The highly unsaturated nature of DHA makes it a potential target for free radical oxidative damage. Increased polyunsaturated fatty acid (PUFA) intake, particularly long-chain PUFAs (LCPUFAs; >18 carbons), may lead to elevated oxidative stress and subsequent membrane damage. 15 Numerous n3-supplementation studies report elevations in low-and highdensity lipoprotein (LDL and HDL)-cholesterol
Reinventing grounded theory: some questions about theory, ground and discovery
Grounded theory’s popularity persists after three decades of broad-ranging critique. In this article three problematic notions are discussed—‘theory,’ ‘ground’ and ‘discovery’—which linger in the continuing use and development of grounded theory procedures. It is argued that far from providing the epistemic security promised by grounded theory, these notions—embodied in continuing reinventions of grounded theory—constrain and distort qualitative inquiry, and that what is contrived is not in fact theory in any meaningful sense, that ‘ground’ is a misnomer when talking about interpretation and that what ultimately materializes following grounded theory procedures is less like discovery and more akin to invention. The procedures admittedly provide signposts for qualitative inquirers, but educational researchers should be wary, for the significance of interpretation, narrative and reflection can be undermined in the procedures of grounded theory
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Preliminary Assessment of Celecoxib and Microdiode Pulse Laser Treatment of Diabetic Macular Edema
Purpose: Inflammation may play an important role in the pathogenesis of diabetic macular edema, a major cause of vision loss in persons with diabetes. The purpose of this study was to evaluate combined antiinflammatory therapy and laser approaches for treating patients with diabetic macular edema. Methods: In this prospective, factorial, randomized, multicenter trial, we compared cyclo-oxygenase-2 inhibitor (celecoxib) with placebo and diode grid laser with standard Early Treatment Diabetic Retinopathy Study focal laser treatment in 86 participants with diabetic macular edema. The primary outcome is change in visual acuity of ≥15 letters from baseline, and the secondary outcomes include a 50% reduction in the retinal thickening of diabetic macular edema measured by optical coherence tomography and a 50% reduction in leakage severity on fluorescein angiography. Results: Visual acuity and retinal thickening data from >2 years of follow-up did not show evidence of differences between the medical and laser treatments. However, participants assigned to the celecoxib group were more likely to have a reduction in fluorescein leakage when compared with the placebo group (odds ratio = 3.6; P < 0.01). Conclusion: This short-term study did not find large visual function benefits of treatment with celecoxib or diode laser compared with those of standard laser treatment. A suggestive effect of celecoxib in reducing fluorescein leakage was observed
Floodwater farming, discontinuous ephemeral streams, and Puebloan abandonment in southwestern Colorado
Geoarchaeological study on the southern piedmont of Sleeping Ute Mountain in southwestern Colorado indicates the presence of discontinuous ephemeral streams that were the foci of episodic Puebloan occupation between A.D. 600s and 1280. Characterized by arroyos, discontinuous ephemeral streams contain alternating aggrading and degrading reaches and are well suited for ak chin floodwater agriculture. Episodic Puebloan abandonment of the southern piedmont correlates with periods of drought but does not appear to be linked to stream entrenchment. We question a priori assumptions of droughts correlated to stream entrenchment and urge caution in the use of drought-arroyo models for settlement shifts in alluvial flood plains without supporting stratigraphic or geomorphic evidence
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