Experimental Potentials for the XΣ+2 and AΠ2 States of NaHe

Experimental potentials for the XΣ+2 and AΠ2 states of the NaHe molecule are presented. The potentials are generated from the temperature dependence of the red wing of the Na resonance line perturbed by He. For the AΠ2 state an unexpectedly large value is obtained for De=480(50) cm−1at Re=4.4(2)a0. The physical basis for this result, which indicates an important role for the internal structure of the rare gas in determining the repulsive part of the alkali-rare-gas interaction, is discussed

Grope metrics on the knot concordance set

To a special type of grope embedded in 4-space, that we call a branchsymmetric grope, we associate a length function for each real number q ≥ 1. This gives rise to a family of pseudo-metrics d q , refining the slice genus metric, on the set of concordance classes of knots, as the infimum of the length function taken over all possible grope concordances between two knots. We investigate the properties of these metrics. The main theorem is that the topology induced by this metric on the knot concordance set is not discrete for all q > 1. The analogous statement for links also holds for q = 1. In addition we translate much previous work on knot concordance into distance statements. In particular, we show that winding number zero satellite operators are contractions in many cases, and we give lower bounds on our metrics arising from knot signatures and higher order signatures. This gives further evidence in favor of the conjecture that the knot concordance group has a fractal structure

Complete characterization of ultrashort pulse sources at 1550 nm

This paper reviews the use of frequency-resolved optical gating (FROG) to characterize mode-locked lasers producing ultrashort pulses suitable for high-capacity optical communications systems at wavelengths around 1550 nm, Second harmonic generation (SHG) FROG is used to characterize pulses from a passively mode-locked erbium-doped fiber laser, and both single-mode and dual-mode gain-switched semiconductor lasers. The compression of gain-switched pulses in dispersion compensating fiber is also studied using SHG-FROG, allowing optimal compression conditions to be determined without a priori assumptions about pulse characteristics. We also describe a fiber-based FROG geometry exploiting cross-phase modulation and show that it is ideally suited to pulse characterization at optical communications wavelengths. This technique has been used to characterize picosecond pulses with energy as low as 24 pJ, giving results in excellent agreement with SHG-FROG characterization, and without any temporal ambiguity in the retrieved puls

The Ursinus Weekly, March 18, 1940

Board elects Nicholas T. Barry new Ursinus Weekly editor • Weiland to edit 1941 Ruby ; Dubuque is business manager • Law and morals Goodrich\u27s subject • Candidates listed for April elections • C.A. Kulp talks on old-age security • Jr. ticket committee explains special price • Snyder sets April 2 for spring Lantern issue • Members of faculty quizzed in poll express sentiments on third term • 21-year voting age favored by students • Party is planned for conference week-end • I.R.C. quizzed on current events; will admit members • Committee heads are selected for women\u27s May Day pageant • Hal Moyer chosen honorary basketball captain for season • Ursinus players on all-star quintets • Infield and outfield candidates report • Dorm battlers vie Wednesday in gym • Frosh won five of twelve games • John DeBold wins conference trophy • Undefeated Temple beaten by co-eds • Conference committee secures two speakers • Vespers speaker points way to achieve true personality • Temple professor to address pre-medical society Tuesdayhttps://digitalcommons.ursinus.edu/weekly/1838/thumbnail.jp

A SUSTAINABLE APPROACH TO THE CONTROL OF PATHOGENS: THE FATE OF STREPTOCOCCI IN EQUINE COMPOST.

Streptococcus equi subspecies equi (S. equi), causes the potentially fatal respiratory disease called “strangles” in horses, while the closely related Streptococcus equi subspecies zooepidemicus (S. zooepidemicus) causes potentially fatal infections in humans. A study was undertaken to determine the survival of these two organisms in equine compost. Compost piles of equine bedding and feed waste were inoculated with 10 x 1010 c.f.u. of S. zooepidemicus and samples taken at 48, 96, 168 and 336 hours relative to samples placed in the pile at 0 hours. No Streptococci were isolated at 48 hours or subsequent time-points. Next, S. equi was similarly inoculated into equine compost, with samples taken at 2, 4, 8, 12, 24, 48, 168 and 336 hours later. No Streptococci were isolated at any time-point. To rule out killing of S. equi by microflora in equine waste, samples of soiled bedding, both autoclaved and un-autoclaved (with water added to match autoclaved moisture) were inoculated with 10 x 1010 c.f.u. of S. zooepidemicus and sampled at 0, 6, 12, 24, 48, 72, 120, 168 and 264 hours. In autoclaved bedding, S. zooepidemicus was isolated from 0 – 120 hours, but replaced by other flora at 264 hours. In un-autoclaved samples, Streptococci were not present after 48 hours. A repeated trial with S. equi yielded similar results. This data suggest that microbial activity of equine waste bedding may eliminate streptococci within 24 - 48 hours, indicating that normal microflora may provide sustainable methods for the control of human and animal pathogens

A SUSTAINABLE APPROACH TO THE CONTROL OF PATHOGENS: THE FATE OF STREPTOCOCCI IN EQUINE COMPOST.

Streptococcus equi subspecies equi (S. equi), causes the potentially fatal respiratory disease called “strangles” in horses, while the closely related Streptococcus equi subspecies zooepidemicus (S. zooepidemicus) causes potentially fatal infections in humans. A study was undertaken to determine the survival of these two organisms in equine compost. Compost piles of equine bedding and feed waste were inoculated with 10 x 1010 c.f.u. of S. zooepidemicus and samples taken at 48, 96, 168 and 336 hours relative to samples placed in the pile at 0 hours. No Streptococci were isolated at 48 hours or subsequent time-points. Next, S. equi was similarly inoculated into equine compost, with samples taken at 2, 4, 8, 12, 24, 48, 168 and 336 hours later. No Streptococci were isolated at any time-point. To rule out killing of S. equi by microflora in equine waste, samples of soiled bedding, both autoclaved and un-autoclaved (with water added to match autoclaved moisture) were inoculated with 10 x 1010 c.f.u. of S. zooepidemicus and sampled at 0, 6, 12, 24, 48, 72, 120, 168 and 264 hours. In autoclaved bedding, S. zooepidemicus was isolated from 0 – 120 hours, but replaced by other flora at 264 hours. In un-autoclaved samples, Streptococci were not present after 48 hours. A repeated trial with S. equi yielded similar results. This data suggest that microbial activity of equine waste bedding may eliminate streptococci within 24 - 48 hours, indicating that normal microflora may provide sustainable methods for the control of human and animal pathogens

Cell Division Resets Polarity and Motility for the Bacterium Myxococcus xanthus

Links between cell division and other cellular processes are poorly understood. It is difficult to simultaneously examine division and function in most cell types. Most of the research probing aspects of cell division has experimented with stationary or immobilized cells or distinctly asymmetrical cells. Here we took an alternative approach by examining cell division events within motile groups of cells growing on solid medium by time-lapse microscopy. A total of 558 cell divisions were identified among approximately 12,000 cells. We found an interconnection of division, motility, and polarity in the bacterium Myxococcus xanthus. For every division event, motile cells stop moving to divide. Progeny cells of binary fission subsequently move in opposing directions. This behavior involves M. xanthus Frz proteins that regulate M. xanthus motility reversals but is independent of type IV pilus “S motility.” The inheritance of opposing polarity is correlated with the distribution of the G protein RomR within these dividing cells. The constriction at the point of division limits the intracellular distribution of RomR. Thus, the asymmetric distribution of RomR at the parent cell poles becomes mirrored at new poles initiated at the site of division

Six-minute walk distance after coronary artery bypass grafting compared with medical therapy in ischaemic cardiomyopathy

Background: In patients with ischaemic left ventricular dysfunction, coronary artery bypass surgery (CABG) may decrease mortality, but it is not known whether CABG improves functional capacity. Objective: To determine whether CABG compared with medical therapy alone (MED) increases 6 min walk distance in patients with ischaemic left ventricular dysfunction and coronary artery disease amenable to revascularisation. Methods: The Surgical Treatment in Ischemic Heart disease trial randomised 1212 patients with ischaemic left ventricular dysfunction to CABG or MED. A 6 min walk distance test was performed both at baseline and at least one follow-up assessment at 4, 12, 24 and/or 36 months in 409 patients randomised to CABG and 466 to MED. Change in 6 min walk distance between baseline and follow-up were compared by treatment allocation. Results: 6 min walk distance at baseline for CABG was mean 340±117 m and for MED 339±118 m. Change in walk distance from baseline was similar for CABG and MED groups at 4 months (mean +38 vs +28 m), 12 months (+47 vs +36 m), 24 months (+31 vs +34 m) and 36 months (−7 vs +7 m), P>0.10 for all. Change in walk distance between CABG and MED groups over all assessments was also similar after adjusting for covariates and imputation for missing values (+8 m, 95% CI −7 to 23 m, P=0.29). Results were consistent for subgroups defined by angina, New York Heart Association class ≥3, left ventricular ejection fraction, baseline walk distance and geographic region. Conclusion: In patients with ischaemic left ventricular dysfunction CABG compared with MED alone is known to reduce mortality but is unlikely to result in a clinically significant improvement in functional capacity

Conservation systematics of the shield-backed trapdoor spiders of the nigrum-group (Mygalomorphae, idiopidae, idiosoma): Integrative taxonomy reveals a diverse and threatened fauna from south-western Australia [dataset]

Supplementary material from: Rix MG, Huey JA, Cooper SJB, Austin AD, Harvey MS (2018) Conservation systematics of the shield-backed trapdoor spiders of the nigrum-group (Mygalomorphae, Idiopidae, Idiosoma): integrative taxonomy reveals a diverse and threatened fauna from south-western Australia. ZooKeys 756: 1-121. https://doi.org/10.3897/zookeys.756.24397 Supplementary material 1: Atlas of morphology : Explanation note: Atlas of morphology for shield-backed trapdoor spiders of the Idiosoma nigrum-group, illustrating a representative selection of male specimens for each species, in five standard views. Supplementary material 2: GenBank data : Explanation note: Spreadsheet of specimens sequenced for the molecular analyses, with associated collection data and GenBank accession numbers. Supplementary material 3: COI dataset : Explanation note: Nexus file of the aligned COI dataset for 82 taxa. Supplementary material 4: FULL dataset : Explanation note: Nexus file of the aligned FULL dataset for 82 taxa. Supplementary material 5: COI p-distances : Explanation note: Spreadsheet with matrix of COI p-distances for 61 sequenced specimens of Idiosoma in the nigrum-group, along with a summary of mean inter- and intra-specific p-distances

Supplemental Feeding for Ecotourism Reverses Diel Activity and Alters Movement Patterns and Spatial Distribution of the Southern Stingray, \u3cem\u3eDasyatis americana\u3c/em\u3e

Southern stingrays, Dasyatis americana, have been provided supplemental food in ecotourism operations at Stingray City Sandbar (SCS), Grand Cayman since 1986, with this site becoming one of the world’s most famous and heavily visited marine wildlife interaction venues. Given expansion of marine wildlife interactive tourism worldwide, there are questions about the effects of such activities on the focal species and their ecosystems. We used a combination of acoustic telemetry and tag-recapture efforts to test the hypothesis that human-sourced supplemental feeding has altered stingray activity patterns and habitat use at SCS relative to wild animals at control sites. Secondarily, we also qualitatively estimated the population size of stingrays supporting this major ecotourism venue. Tag-recapture data indicated that a population of at least 164 stingrays, over 80% female, utilized the small area at SCS for prolonged periods of time. Examination of comparative movements of mature female stingrays at SCS and control sites revealed strong differences between the two groups: The fed animals demonstrated a notable inversion of diel activity, being constantly active during the day with little movement at night compared to the nocturnally active wild stingrays; The fed stingrays utilized significantly (