417 research outputs found
The Effects of Drought on Foraging Habitat Selection of Breeding Wood Storks in Coastal Georgia
Foraging habitat use by Wood Storks (Mycteria americana) during the breeding season was studied for three coastal colonies during a drought year and compared to habitat use during normal rainfall years. Information on the distribution of wetland habitat types was derived using U.S. Fish and Wildlife Service National Wetland In- ventory (NWI) data within a Geographic Information System (GIS). Foraging locations were obtained by following storks from their colonies in a fixed-winged aircraft. Differences in hydrologic condition and, the resulting prey availability in coastal zone freshwater wetlands greatly affected foraging habitat use and breeding success of the three stork colonies. In 1997 (dry), although the foraging range of each colony did not differ from wetter years, storks used estuarine foraging habitats much more extensively. Breeding success (fledged young/nest) in 1997 was less than half the success of the wetter years. Palustrine (freshwater) wetlands seem very important to storks breed- ing along the Georgia coast. During dry years, estuarine wetlands, by themselves, do not appear to be able to support the breeding population of storks in this region. Reasons why these productive wetlands do not provide sufficient resources for successful breeding are unclear, but could include limitations to only two foraging periods (low tides) in a 24-hr period
The Effects of Drought on Foraging Habitat Selection of Breeding Wood Storks in Coastal Georgia
Foraging habitat use by Wood Storks (Mycteria americana) during the breeding season was studied for three coastal colonies during a drought year and compared to habitat use during normal rainfall years. Information on the distribution of wetland habitat types was derived using U.S. Fish and Wildlife Service National Wetland In- ventory (NWI) data within a Geographic Information System (GIS). Foraging locations were obtained by following storks from their colonies in a fixed-winged aircraft. Differences in hydrologic condition and, the resulting prey availability in coastal zone freshwater wetlands greatly affected foraging habitat use and breeding success of the three stork colonies. In 1997 (dry), although the foraging range of each colony did not differ from wetter years, storks used estuarine foraging habitats much more extensively. Breeding success (fledged young/nest) in 1997 was less than half the success of the wetter years. Palustrine (freshwater) wetlands seem very important to storks breed- ing along the Georgia coast. During dry years, estuarine wetlands, by themselves, do not appear to be able to support the breeding population of storks in this region. Reasons why these productive wetlands do not provide sufficient resources for successful breeding are unclear, but could include limitations to only two foraging periods (low tides) in a 24-hr period
A Space-Time Orbifold: A Toy Model for a Cosmological Singularity
We explore bosonic strings and Type II superstrings in the simplest time
dependent backgrounds, namely orbifolds of Minkowski space by time reversal and
some spatial reflections. We show that there are no negative norm physical
excitations. However, the contributions of negative norm virtual states to
quantum loops do not cancel, showing that a ghost-free gauge cannot be chosen.
The spectrum includes a twisted sector, with strings confined to a ``conical''
singularity which is localized in time. Since these localized strings are not
visible to asymptotic observers, interesting issues arise regarding unitarity
of the S-matrix for scattering of propagating states. The partition function of
our model is modular invariant, and for the superstring, the zero momentum
dilaton tadpole vanishes. Many of the issues we study will be generic to
time-dependent cosmological backgrounds with singularities localized in time,
and we derive some general lessons about quantizing strings on such spaces.Comment: 21 pages, 2 figure
Harvard Law School Lambda Second Annual Gay and Lesbian Legal Advocacy Conference: âDonât Ask, Donât Tellâ
Researching digital inequalities in childrenâs play with technology in South Africa
This paper reports on the South African findings from an international mixed methods study between the LEGO Foundation, Dubit and the Universities of Sheffield (England) and Cape Town (South Africa) on young childrenâs learning with digital technology. The findings of the study, the first of its kind in South Africa, show the consistency of qualities and experience of play, but also reveal socio-economic, linguistic, ethnic, gender and racial inequalities in the play environments of both groups of 3â11-year-olds. Yet, despite these structural inequalities, the play ecologies of children in resource-constrained environments show their creativity within the digital/non-digital environment. The paper discusses some of the analytical tools used and the geo-political issues raised, and considers these in conjunction with selected data. We conclude that the different socio-cultural conditions and geo-political realities offer new insights about the role global education research can play in helping combat structural inequalities in resource-constrained environments
Brexit and the everyday politics of emotion: methodological lessons from history
The 2016 European Union referendum campaign has been depicted as a battle between âheadsâ and âheartsâ, reason and emotion. Votersâ propensity to trust their feelings over expert knowledge has sparked debate about the future of democratic politics in what is increasingly believed to be an âage of emotionâ. In this article, we argue that we can learn from the ways that historians have approached the study of emotions and everyday politics to help us make sense of this present moment. Drawing on William Reddyâs concept of âemotional regimesâ, we analyse the position of emotion in qualitative, âeveryday narrativesâ about the 2016 European Union referendum. Using new evidence from the Mass Observation Archive, we argue that while reason and emotion are inextricable facets of political decision-making, citizens themselves understand the two processes as distinct and competing
Intentional Weight Loss and Dose Reductions of Anti-Diabetic Medications â A Retrospective Cohort Study
BACKGROUND AND AIM: Intentional weight loss, primarily by improving insulin resistance, is known to decrease the need for anti-diabetic medications. In this study, we assess the magnitude of weight loss that resulted in dose reductions or discontinuation of anti-diabetic medications in overweight or obese patients with type 2 diabetes (DM) undergoing weight loss treatment. METHODS: Case records of 50 overweight or obese patients with DM who successfully decreased dosage or discontinued diabetes medications after losing weight via attendance at two University-based, outpatient weight management centers were analyzed. Follow-up visits, weight reduction interventions, and decisions for dose reductions or discontinuation of medications were individualized to patient needs by the treating physician. RESULTS: Mean starting BMI was 35 kg/m(2), mean age 53.4 years, and 58% were male. All 50 used at least one anti-diabetic medication (30 metformin, 39 sulfonylureas, 31 insulin, 21 sitagliptin) to manage blood sugar. Mean duration of follow-up was 30.2 months. Mean weight loss was 10.8 ± 4.1 kgs (11.1% of initial body weight ± 4.7%). 22/50 patients (44%) discontinued anti-diabetes medications (14 sulfonylureas [36%], 7 insulin [23%], 4 sitagliptin [19%]). The mean percentage weight loss achieved at the point of successful discontinuation of medication was 11.2% ± 3.5% (14% for sulphonylureas, 11% for insulin, and 7.1% for sitagliptin). Mean percentage weight loss of 5.6% ± 2.8% (5.1% for sulphonylureas, 4.3% for insulin, and 7.1% for sitagliptin) was required for initial dose reduction. For every 5% weight loss, predicted dose reductions were sulphonylureas, 39%; insulin, 42%; and any anti-diabetic medications, 49%. CONCLUSION: Among overweight or obese patients with type 2 diabetes, intentional weight loss of 7-14% was typically required for full discontinuation of at least one anti-diabetic medication. Discontinuation of insulin was achieved at a mean weight reduction of 11% of initial body weight
HST/COS Observations of Thirteen New He II Quasars
The full reionization of intergalactic helium was a major event in the
history of the IGM, and UV observations of the He II Gunn-Peterson trough allow
us to characterize the end of this process at z~3. Due to intervening hydrogen
absorption, quasars allowing such study are rare, with only 33 known in the
literature, and most of those are very recent discoveries. We expand on our
previous discovery work, and present 13 new He II quasars with redshifts 2.82 <
z < 3.77, here selected with ~80% efficiency, and including several that are
much brighter than the vast majority of those previously known. This is the
largest sample of uniformly observed He II quasars covering such a broad
redshift range, and they show evidence of IGM opacity increasing with redshift,
as expected for the helium reionization epoch. No evidence of He II Ly{\alpha}
quasar emission is seen in individual or averaged spectra, posing a problem for
standard models of the broad line region. The current rapid advance in the
study of He II quasars has been greatly facilitated by the Cosmic Origins
Spectrograph on HST, and we discuss the instrumental and other subtleties that
must be taken into account in IGM He II observations.Comment: AJ accepted; 14 pages, 7 figure
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A novel 3D imaging system for strawberry phenotyping
Accurate and quantitative phenotypic data in plant breeding programmes is vital in breeding to assess the performance of genotypes and to make selections. Traditional strawberry phenotyping relies on the human eye to assess most external fruit quality attributes, which is time-consuming and subjective. 3D imaging is a promising high-throughput technique that allows multiple external fruit quality attributes to be measured simultaneously. A low cost multi-view stereo (MVS) imaging system was developed, which captured data from 360° around a target strawberry fruit. A 3D point cloud of the sample was derived and analysed with custom-developed software to estimate berry height, length, width, volume, calyx size, colour and achene number. Analysis of these traits in 100 fruits showed good concordance with manual assessment methods. This study demonstrates the feasibility of an MVS based 3D imaging system for the rapid and quantitative phenotyping of seven agronomically important external strawberry traits. With further improvement, this method could be applied in strawberry breeding programmes as a cost effective phenotyping technique
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