4,328 research outputs found
Algebraic Topology of Calabi-Yau Threefolds in Toric Varieties
We compute the integral homology (including torsion), the topological
K-theory, and the Hodge structure on cohomology of Calabi-Yau threefold
hypersurfaces and complete intersections in Gorenstein toric Fano varieties.
The methods are purely topological
Downward shortwave surface irradiance from 17 sites for the FIRE/SRB Wisconsin experiment
A field experiment was conducted in Wisconsin during Oct. to Nov. 1986 for purposes of both intensive cirrus cloud measurments and SRB algorithm validation activities. The cirrus cloud measurements were part of the FIRE. Tables are presented which show data from 17 sites in the First ISCCP (International Satellite Cloud Climatology Project) Regional Experiment/Surface Radiation Budget (FIRE/SRB) Wisconsin experiment region. A discussion of intercomparison results and calibration inconsistencies is also included
Masses of Neutron Stars in High-Mass X-ray Binaries with Optical Astrometry
Determining the type of matter that is inside a neutron star (NS) has been a
long-standing goal of astrophysics. Despite this, most of the NS equations of
state (EOS) that predict maximum masses in the range 1.4-2.8 solar masses are
still viable. Most of the precise NS mass measurements that have been made to
date show values close to 1.4 solar masses, but a reliable measurement of an
over-massive NS would constrain the EOS possibilities. Here, we investigate how
optical astrometry at the microarcsecond level can be used to map out the
orbits of High-Mass X-ray Binaries (HMXBs), leading to tight constraints on NS
masses. While previous studies by Unwin and co-workers and Tomsick and
co-workers discuss the fact that the future Space Interferometry Mission should
be capable of making such measurements, the current work describes detailed
simulations for 6 HMXB systems, including predicted constraints on all orbital
parameters. We find that the direct NS masses can be measured to an accuracy of
2.5% (1-sigma) in the best case (X Per), to 6.5% for Vela X-1, and to 10% for
two other HMXBs.Comment: 8 pages, Accepted by Ap
Towards an Improved High Resolution Global Long-Term Solar Resource Database
This paper presents an overview of an ongoing project to develop and deliver a solar mapping processing system to the National Renewable Energy Laboratory (NREL) using the data sets that are planned for production at the National Climatic Data Center (NCDC). NCDC will be producing a long-term radiance and cloud property data set covering the globe every three hours at an approximate resolution of 10 x 10 km. NASA, the originators of the Surface meteorology and Solar Energy web portal are collaborating with SUNY-Albany to develop the production system and solar algorithms. The initial result will be a global long-term solar resource data set spanning over 25 years. The ultimate goal of the project is to also deliver this data set and production system to NREL for continual production. The project will also assess the impact of providing these new data to several NREL solar decision support tools
Links between dissipation, intermittency, and helicity in the GOY model revisited
High-resolution simulations within the GOY shell model are used to study
various scaling relations for turbulence. A power-law relation between the
second-order intermittency correction and the crossover from the inertial to
the dissipation range is confirmed. Evidence is found for the intermediate
viscous dissipation range proposed by Frisch and Vergassola. It is emphasized
that insufficient dissipation-range resolution systematically drives the energy
spectrum towards statistical-mechanical equipartition. In fully resolved
simulations the inertial-range scaling exponents depend on both model
parameters; in particular, there is no evidence that the conservation of a
helicity-like quantity leads to universal exponents.Comment: 24 pages, 13 figures; submitted to Physica
‘Instead of fetching flowers, the youths brought in flakes of snow’: exploring extreme weather history through English parish registers
Parish registers provide organized, dated and located population data and as such, are routinely among the most frequently consulted documents within the holdings of county record offices and archives. Throughout history, extreme weather has had significant impacts on the church, its congregation, and local landscape. It is for these reasons that extreme weather events have been deemed worthy of official note by authors of many registers. Although isolated entries have been used as supporting evidence for the occurrence of a number of historic extreme weather events, the information that parish registers contain relating to weather history has not been studied in its own right. Parish register narratives add new events to existing chronologies of extreme weather events and contribute to our understanding of their impacts at the local level. As public and well used documents they also function to keep the memory of particular events alive. The examples in this paper cover a wide range of weather types, places, and time periods, also enabling recording practice to be explored. Finally, as the number of digitized registers increases, we highlight the risks of weather narratives being obscured, and reflect on how the weather history contained within might be systematically captured
Tanzania's reptile biodiversity : Distribution, threats and climate change vulnerability
Assessments of biodiversity patterns and threats among African reptiles have lagged behind those of other vertebrate groups and regions. We report the first systematic assessment of the distribution, threat status, and climate change vulnerability for the reptiles of Tanzania. A total of 321 reptile species (including 90 Tanzanian endemics) were assessed using the global standard IUCN Red List methodology and 274 species were also assessed using the IUCN guidelines for climate change vulnerability. Patterns of species richness and threat assessment confirm the conservation importance of the Eastern Arc Mountains, as previously demonstrated for birds, mammals and amphibians. Lowland forests and savannah-woodland habitats also support important reptile assemblages. Protected area gap analysis shows that 116 species have less than 20% of their distribution ranges protected, among which 12 are unprotected, eight species are threatened and 54 are vulnerable to climate change. Tanzania's northern margins and drier central corridor support high numbers of climate vulnerable reptile species, together with the eastern African coastal forests and the region between Lake Victoria and Rwanda. This paper fills a major gap in our understanding of the distribution and threats facing Tanzania's reptiles, and demonstrates more broadly that the explicit integration of climate change vulnerability in Red Listing criteria may revise spatial priorities for conservation
Profiles of physical, emotional and psychosocial wellbeing in the Lothian birth cohort 1936
<p>Abstract</p> <p>Background</p> <p>Physical, emotional, and psychosocial wellbeing are important domains of function. The aims of this study were to explore the existence of separable groups among 70-year olds with scores representing physical function, perceived quality of life, and emotional wellbeing, and to characterise any resulting groups using demographic, personality, cognition, health and lifestyle variables.</p> <p>Methods</p> <p>We used latent class analysis (LCA) to identify possible groups.</p> <p>Results</p> <p>Results suggested there were 5 groups. These included High (n = 515, 47.2% of the sample), Average (n = 417, 38.3%), and Poor Wellbeing (n = 37, 3.4%) groups. The two other groups had contrasting patterns of wellbeing: one group scored relatively well on physical function, but low on emotional wellbeing (Good Fitness/ Low Spirits,n = 60, 5.5%), whereas the other group showed low physical function but relatively well emotional wellbeing (Low Fitness/Good Spirits, n = 62, 5.7%). Salient characteristics that distinguished all the groups included smoking and drinking behaviours, personality, and illness.</p> <p>Conclusions</p> <p>Despite there being some evidence of these groups, the results also support a largely one-dimensional construct of wellbeing in old age—for the domains assessed here—though with some evidence that some individuals have uneven profiles.</p
- …
