Sensible heat loss from Muskoxen (Ovibos moschatus) feeding in winter: small calves are not at a thermal disadvantage compared with adult cows

Muskoxen (Ovibos moschatus) are large (\u3e200 kg adult body mass) mammalian herbivores that overwinter in the polar regions. Calves are around one-third the body mass of mature females and may be expected to suffer greater thermal stresses in winter compared with adults because the ratio of surface area to volume (SA : vol) is much greater for calves than for adults. We found that during feeding bouts, when animals are fully exposed to environmental conditions, calves did lose sensible (dry) heat more readily than adults (W m(-2)) in still air conditions. However, calves and cows lost less than 2%-6% of their estimated daily digestible energy intake as conductive, convective, and radiant heat losses accumulated during feeding bouts. More important, calves did not lose relatively more heat than larger adults in terms of sensible losses as part of their daily energy intake. Coat surface temperatures were only 2 degrees-5 degrees C above ambient even when air temperature fell to -40 degrees C. Body temperatures recorded deep within the ear canal near the tympanum fluctuated in both cows and calves. Muskoxen combine peripheral heterothermy and an exceptional winter coat to minimize sensible heat loss in winter. These mechanisms appear to have circumvented some of the thermal problems normally associated with a high SA : vol ratio in calves, which reflects the strong selection to conserve energy in winter

Inverse monoids and immersions of 2-complexes

It is well known that under mild conditions on a connected topological space $\mathcal X$, connected covers of $\mathcal X$ may be classified via conjugacy classes of subgroups of the fundamental group of $\mathcal X$. In this paper, we extend these results to the study of immersions into 2-dimensional CW-complexes. An immersion $f : {\mathcal D} \rightarrow \mathcal C$ between CW-complexes is a cellular map such that each point $y \in {\mathcal D}$ has a neighborhood $U$ that is mapped homeomorphically onto $f(U)$ by $f$. In order to classify immersions into a 2-dimensional CW-complex $\mathcal C$, we need to replace the fundamental group of $\mathcal C$ by an appropriate inverse monoid. We show how conjugacy classes of the closed inverse submonoids of this inverse monoid may be used to classify connected immersions into the complex

Cross-Identification of Stars with Unknown Proper Motions

The cross-identification of sources in separate catalogs is one of the most basic tasks in observational astronomy. It is, however, surprisingly difficult and generally ill-defined. Recently Budav\'ari & Szalay (2008) formulated the problem in the realm of probability theory, and laid down the statistical foundations of an extensible methodology. In this paper, we apply their Bayesian approach to stars that, we know, can move measurably on the sky, with detectable proper motion, and show how to associate their observations. We study models on a sample of stars in the Sloan Digital Sky Survey, which allow for an unknown proper motion per object, and demonstrate the improvements over the analytic static model. Our models and conclusions are directly applicable to upcoming surveys such as PanSTARRS, the Dark Energy Survey, Sky Mapper, and the LSST, whose data sets will contain hundreds of millions of stars observed multiple times over several years.Comment: 10 pages, 5 figure

Using Focus Groups to Assess Educational Programming Needs in Forestry

Extension professionals are continually faced with the challenge of effectively communicating relevant information to an ever-evolving audience with diverse interests. Using focus group data, this article highlights specific educational programming needs of nonindustrial private forest landowners (NIPFs) in Mississippi. Findings indicate NIPFs are more likely to adopt new ideas if educational programming is tailored to their specific needs, consequently indicating the need to group the audience by their interests. Data also emphasize the importance of employing new technology as means for communicating more efficiently

Regular obstructed categories and TQFT

A proposal of the concept of $n$-regular obstructed categories is given. The corresponding regularity conditions for mappings, morphisms and related structures in categories are considered. An n-regular TQFT is introduced. It is shown the connection of time reversibility with the regularity.Comment: 22 pages in Latex. To be published in J. Math. Phy

The role and safety of endobronchial ultrasound-guided transbronchial needle aspiration in the diagnosis and management of infected bronchogenic mediastinal cysts in adults

Bronchogenic and other duplication cysts are congenital abnormalities that can present at any age including adulthood years. They are usually asymptomatic and discovered incidentally on radiological imaging of the chest. They are commonly treated by surgical resection. Recently, endobronchial ultrasound has been used to assist in diagnosis when radiologic imaging is not definitive. Endobronchial ultrasound has been used rarely to drain infected cysts, a rare complication of the bronchogenic cyst. We present a unique case of an infected large bronchogenic cyst treated with endobronchial ultrasound drainage combined with conservative medical therapy. We also review the scarce available literature describing such an approach and its potential complications and add recommendations based on our experience in managing these anomalies

A Detailed Model Atmosphere Analysis of Cool White Dwarfs in the Sloan Digital Sky Survey

We present optical spectroscopy and near-infrared photometry of 126 cool white dwarfs in the Sloan Digital Sky Survey (SDSS). Our sample includes high proper motion targets selected using the SDSS and USNO-B astrometry and a dozen previously known ultracool white dwarf candidates. Our optical spectroscopic observations demonstrate that a clean selection of large samples of cool white dwarfs in the SDSS (and the SkyMapper, Pan-STARRS, and the Large Synoptic Survey Telescope datasets) is possible using a reduced proper motion diagram and a tangential velocity cut-off (depending on the proper motion accuracy) of 30 km/s. Our near-infrared observations reveal eight new stars with significant absorption. We use the optical and near-infrared photometry to perform a detailed model atmosphere analysis. More than 80% of the stars in our sample are consistent with either pure hydrogen or pure helium atmospheres. However, the eight stars with significant infrared absorption and the majority of the previously known ultracool white dwarf candidates are best explained with mixed hydrogen and helium atmosphere models. The age distribution of our sample is consistent with a Galactic disk age of 8 Gyr. A few ultracool white dwarfs may be as old as 12-13 Gyr, but our models have problems matching the spectral energy distributions of these objects. There are only two halo white dwarf candidates in our sample. However, trigonometric parallax observations are required for accurate mass and age determinations and to confirm their membership in the halo.Comment: ApJ Supplements, in pres

Classical Structures Based on Unitaries

Starting from the observation that distinct notions of copying have arisen in different categorical fields (logic and computation, contrasted with quantum mechanics) this paper addresses the question of when, or whether, they may coincide. Provided all definitions are strict in the categorical sense, we show that this can never be the case. However, allowing for the defining axioms to be taken up to canonical isomorphism, a close connection between the classical structures of categorical quantum mechanics, and the categorical property of self-similarity familiar from logical and computational models becomes apparent. The required canonical isomorphisms are non-trivial, and mix both typed (multi-object) and untyped (single-object) tensors and structural isomorphisms; we give coherence results that justify this approach. We then give a class of examples where distinct self-similar structures at an object determine distinct matrix representations of arrows, in the same way as classical structures determine matrix representations in Hilbert space. We also give analogues of familiar notions from linear algebra in this setting such as changes of basis, and diagonalisation.Comment: 24 pages,7 diagram

Identification of A-colored Stars and Structure in the Halo of the Milky Way from SDSS Commissioning Data

A sample of 4208 objects with magnitude 15 < g* < 22 and colors of main sequence A stars has been selected from 370 square degrees of Sloan Digital Sky Survey (SDSS) commissioning observations. The data is from two long, narrow stripes, each with an opening angle of greater than 60 deg, at Galactic latitudes 36 < abs(b) < 63 on the celestial equator. An examination of the sample's distribution shows that these stars trace considerable substructure in the halo. Large overdensities of A-colored stars in the North at (l,b,R) = (350, 50, 46 kpc) and in the South at (157, -58, 33 kpc) and extending over tens of degrees are present in the halo of the Milky Way. Using photometry to separate the stars by surface gravity, both structures are shown to contain a sequence of low surface gravity stars consistent with identification as a blue horizontal branch (BHB). Both structures also contain a population of high surface gravity stars two magnitudes fainter than the BHB stars, consistent with their identification as blue stragglers (BSs). From the numbers of detected BHB stars, lower limits to the implied mass of the structures are 6x10^6 M_sun and 2x10^6 M_sun. The fact that two such large clumps have been detected in a survey of only 1% of the sky indicates that such structures are not uncommon in the halo. Simple spheroidal parameters are fit to a complete sample of the remaining unclumped BHB stars and yield (at r < 40 kpc) a fit to a halo distribution with flattening (c/a = 0.65+/-0.2) and a density falloff exponent of alpha = -3.2+/-0.3.Comment: AASTeX v5_0, 26 pages, 1 table, 20 figures, ApJ accepte