Accelerometers and simple algorithms identify activity budgets and body orientation in African elephants Loxodonta africana

Accelerometers can be used to monitor animal behavior remotely, but validation is required for each species. Previously, we showed that accelerometer data in collars could be used to identify specific behaviors in African elephants Loxodonta africana, using complex analytical methods. Here, we show that simple methods can also be used to identify elephant activity levels and body orientation. Subjects were 6 African elephants: 3 at Disney’s Animal Kingdom®, Florida, USA, and 3 in Samburu-Laikipia, Kenya. Each elephant wore a collar containing a tri-axial accelerometer positioned on top of the neck. Simultaneous video recordings allowed validation of accelerometer data against observed behavior. The standard deviation of the total acceleration was shown to be a valid measure of dynamic acceleration, differentiating activity levels associated with resting, feeding, bathing, walking, and rapid walking. The mean of the total acceleration was shown to be a valid measure of static acceleration, and indicated upright and recumbent orientations. Simulations showed how accuracy was affected by sample rate, number of axes examined, and analysis window lengths. Based on 34 continuous 24 h acceleration streams, the 6 elephants exhibited an average of 2.5 h of overnight recumbence associated with minimal movement, indicating sleep. Daily activity budgets exhibited periods of minimal activity (e.g. resting, 17%), low activity (e.g. feeding, 68%), medium activity (e.g. walking, 13%), and high activity (e.g. rapid walking, 2%). Kenyan elephants were slightly more active and exhibited less restful recumbence compared to zoo elephants. Accelerometers in elephant collars can detect activity levels that are associated with specific behaviors, and can detect body orientation as a proxy for sleep

Contrasting surface velocities between lake- and land-terminating glaciers in the Himalayan region

This research has been supported by the Swiss National Science Foundation (grant no. IZLCZ2_169979/1) and the Strategic Priority Research Program of Chinese Academy of Sciences (grant no. XDA20100300). Bert Wouters has been supported by NWO VIDI (grant no. 016.Vidi.171.063).Meltwater from Himalayan glaciers sustains the flow of rivers such as the Ganges and Brahmaputra on which over half a billion people depend for day-to-day needs. Upstream areas are likely to be affected substantially by climate change, and changes in the magnitude and timing of meltwater supply are expected to occur in coming decades. About 10 % of the Himalayan glacier population terminates into proglacial lakes, and such lake-terminating glaciers are known to exhibit higher-than-average total mass losses. However, relatively little is known about the mechanisms driving exacerbated ice loss from lake-terminating glaciers in the Himalaya. Here we examine a composite (2017–2019) glacier surface velocity dataset, derived from Sentinel 2 imagery, covering central and eastern Himalayan glaciers larger than 3 km2. We find that centre flow line velocities of lake-terminating glaciers (N = 70; umedian: 18.83 m yr−1; IQR – interquartile range – uncertainty estimate: 18.55–19.06 m yr−1) are on average more than double those of land-terminating glaciers (N = 249; umedian: 8.24 m yr−1; IQR uncertainty estimate: 8.17–8.35 m yr−1) and show substantially more heterogeneity than land-terminating glaciers around glacier termini. We attribute this large heterogeneity to the varying influence of lakes on glacier dynamics, resulting in differential rates of dynamic thinning, which causes about half of the lake-terminating glacier population to accelerate towards the glacier termini. Numerical ice-flow model experiments show that changes in the force balance at the glacier termini are likely to play a key role in accelerating the glacier flow at the front, with variations in basal friction only being of modest importance. The expansion of current glacial lakes and the formation of new meltwater bodies will influence the dynamics of an increasing number of Himalayan glaciers in the future, and these factors should be carefully considered in regional projections.Publisher PDFPeer reviewe

Stability and BPS branes

We define the concept of Pi-stability, a generalization of mu-stability of vector bundles, and argue that it characterizes N=1 supersymmetric brane configurations and BPS states in very general string theory compactifications with N=2 supersymmetry in four dimensions.Comment: harvmac, 18 p

The spectrum of BPS branes on a noncompact Calabi-Yau

We begin the study of the spectrum of BPS branes and its variation on lines of marginal stability on O_P^2(-3), a Calabi-Yau ALE space asymptotic to C^3/Z_3. We show how to get the complete spectrum near the large volume limit and near the orbifold point, and find a striking similarity between the descriptions of holomorphic bundles and BPS branes in these two limits. We use these results to develop a general picture of the spectrum. We also suggest a generalization of some of the ideas to the quintic Calabi-Yau.Comment: harvmac, 45 pp. (v2: added references

The BPS Spectrum of N=2 SU(N) SYM and Parton Branes

We apply ideas that have appeared in the study of D-branes on Calabi-Yau compactifications to the derivation of the BPS spectrum of field theories. In particular, we identify an orbifold point whose fractional branes can be thought of as ``partons'' of the BPS spectrum of N=2 pure SU(N) SYM. We derive the BPS spectrum and lines of marginal stability branes near that orbifold, and compare our results with the spectrum of the field theories.Comment: 29 pages, 4 figures, includes package diagrams.tex by Paul Taylo

The utility of the REM latency test in psychiatric diagnosis: A study of 81 depressed outpatients

To examine the utility of the REM (rapid eye movement) latency test in identifying outpatient primary depressions, 81 consecutive referrals to a sleep disorders center were evaluated in a phenomenologic, sleep polygraphic, and psychometric study. Modified Feighner (St. Louis) diagnoses were definite primary depression (n=19), probable primary depression (n=30), depression chronologically secondary to preexisting psychiatric disorders (n=19), and nonaffective psychiatric disorder (n=13). There were 18 nonpsychiatric controls. REM latency less than 70 minutes on 2 consecutive nights detected 62% of primary depressions, discriminating them from the other diagnostic groups with 88% specificity. There were no false positives among controls. These data provided a 90% confidence for the diagnosis of primary depression in this outpatient sample. Requiring 2 consecutive nights of shortened REM latency appears to improve significantly the specificity of a test previously considered to have high sensitivity but relatively low specificity for depressive disorders.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23905/1/0000148.pd

REM density in the differential diagnosis of psychiatric from medical-neurologic disorders: A replication

The discriminatory power of rapid eye movement (REM) density in 61 outpatients with medical, neurologic, and psychiatric disorders and 8 noncase controls was assessed. REM density was significantly lower in a group of patients with medical-neurologic disease as compared with psychiatric and control subjects without evidence for such disease. Furthermore, low scores discriminated depressions occurring in the context of somatic disease when compared with those in the absence of such disease. The differences between groups were not accounted for by age or sex. The cutoff REM density score of 12.56, based on the 99% lower confidence limit of the noncase controls, provided the highest sensitivity (0.82) without loss of specificity (0.80). It was concluded that REM density may have merit as a general measure of diffuse central nervous system pathology, whether primary or secondary to widespread systemic disease. The findings of Kupfer's group are upheld and extended to a broader medical and neuropsychiatric population than in the original Pittsburgh study.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24174/1/0000433.pd

A sedge plant as the source of Kangaroo Island propolis rich in prenylated p-coumarate ester and stilbenes

AbstractPropolis samples from Kangaroo Island, South Australia, were investigated for chemical constituents using high-field nuclear magnetic resonance spectral profiling. A type of propolis was found containing a high proportion of prenylated hydroxystilbenes. Subsequently, the botanical origin of this type of propolis was identified using a beehive propolis depletion method and analysis of flora. Ligurian honey bees, Apis mellifera ligustica Spinola, were found to produce propolis from resin exuded by the Australian native sedge plant Lepidosperma sp. Montebello (Cyperaceae). The plants, commonly known as sword sedge, were found to have resin that matched with the propolis samples identified as the most abundant propolis type on the island containing C- and O-prenylated tetrahydroxystilbenes (pTHOS) in addition to a small amount of prenylated p-coumarate. The isolation of five pTHOS not previously characterized are reported: (E)-4-(3-methyl-2-buten-1-yl)-3,4′,5-trihydroxy-3′-methoxystilbene, (E)-2,4-bis(3-methyl-2-buten-1-yl)-3,3′,4′,5-tetrahydroxystilbene, (E)-2-(3-methyl-2-buten-1-yl)-3-(3-methyl-2-butenyloxy)-3′,4′,5-trihydroxystilbene, (E)-2,6-bis(3-methyl-2-buten-1-yl)-3,3′,5,5′-tetrahydroxystilbene and (E)-2,6-bis(3-methyl-2-buten-1-yl)-3,4′,5-trihydroxy-3′-methoxystilbene. A National Cancer Institute 60 human cell line anticancer screen of three of these compounds showed growth inhibitory activity. The large Australasian genus Lepidosperma is identified as a valuable resource for the isolation of substances with medicinal potential

Remarks on quiver gauge theories from open topological string theory

We study effective quiver gauge theories arising from a stack of D3-branes on certain Calabi-Yau singularities. Our point of view is a first principle approach via open topological string theory. This means that we construct the natural A-infinity-structure of open string amplitudes in the associated D-brane category. Then we show that it precisely reproduces the results of the method of brane tilings, without having to resort to any effective field theory computations. In particular, we prove a general and simple formula for effective superpotentials

Isospin Multiplet Structure in Ultra--Heavy Fermion Bound States

The coupled Bethe--Salpeter bound state equations for a $Q\bar Q$ system, where $Q=(U,D)$ is a degenerate, fourth generation, super--heavy quark doublet, are solved in several ladder approximation models. The exchanges of gluon, Higgs and Goldstone modes in the standard model are calculated in the ultra--heavy quark limit where weak $\gamma, W^\pm$ and $Z^0$ contributions are negligible. A natural $I=0$ and $I=1$ multiplet pattern is found, with large splittings occuring between the different weak iso--spin states when $M_Q$, the quark masses, are larger than values in the range $0.4 TeV<M_Q<0.8 TeV$, depending on which model is used. Consideration of ultra--heavy quark lifetime constraints and $U-D$ mass splitting constraints are reviewed to establish the plausibility of lifetime and mass degeneracy requirements assumed for this paper.Comment: 20 pages, 7 figures (hard copy available upon request), report# KU-HEP-93-2