Temporary Emigration Of Female Weddell Seals Prior To First Reproduction

Temporary emigration (TE) from a breeding site is common in some colonial-breeding species, but implications are poorly understood because TE is difficult to quantify. We used capture-mark-recapture models and a dataset of 5450 female Weddell seals (Leptonychotes weddellii) born in Erebus Bay, Antarctica to investigate sources of variation in TE rates and evaluate possible implications for recruitment. Temporary emigration rates and recruitment rates were state- and age-dependent and annually variable. For seals that attended reproductive colonies the previous year, mean TE rates decreased from 0.98 (sd = 0.02) at age 1 to 0.15 (sd = 0.16) at age 8, whereas mean recruitment rates increased from 0.06 (sd = 0.03) at age 5 to 0.52 (sd= 0.16) at age 10. Seals that did not attend reproductive colonies the previous year had greater TE rates and lower recruitment rates than seals that did attend colonies, but the confidence interval for the effect of TE on recruitment included zero. Our results suggest that 1) motivation to emigrate varies temporally depending on environmental conditions, 2) as seals grow older they have increased motivation to attend reproductive colonies even before they are ready to recruit, and 3) some seals appear to always be more likely than others to emigrate. We suspect that TE may allow seals to buffer variability in survival rates

Environmental Variation and Cohort Effects in an Antarctic Predator

Understanding the potential influence of environmental variation experienced by animals during early stages of development on their subsequent demographic performance can contribute to our understanding of population processes and aid in predicting impacts of global climate change on ecosystem functioning. Using data from 4,178 tagged female Weddell seal pups born into 20 different cohorts, and 30 years of observations of the tagged seals, we evaluated the hypothesis that environmental conditions experienced by young seals, either indirectly through maternal effects and/or directly during the initial period of juvenile nutritional independence, have long-term effects on individual demographic performance. We documented an approximately 3-fold difference in the proportion of each cohort that returned to the pupping colonies and produced a pup within the first 10 years after birth. We found only weak evidence for a correlation between annual environmental conditions during the juvenile-independence period and cohort recruitment probability. Instead, the data strongly supported an association between cohort recruitment probability and the regional extent of sea ice experienced by the mother during the winter the pup was in utero. We suggest that inter-annual variation in winter sea-ice extent influences the foraging success of pregnant seals by moderating the regional abundance of competing predators that cannot occupy areas of consolidated sea ice, and by directly influencing the abundance of mid-trophic prey species that are sea-ice obligates. We hypothesize that this environmentally-induced variation in maternal nutrition dictates the extent of maternal energetic investment in offspring, resulting in cohort variation in mean size of pups at weaning which, in turn, contributes to an individual?s phenotype and its ultimate fitness. These linkages between sea ice and trophic dynamics, combined with demonstrated and predicted changes in the duration and extent of sea ice associated with climate change, suggest significant alterations in Antarctic marine ecosystems in the future

The Ursinus Weekly, February 12, 1951

New high set by B-list group as 106 qualify • Y schedules chats, conducts retreat • Paynter-Keller production scores hit in Curtain Club group presentation • Play contest in progress; May Day heads named • Alumna to speak at girls\u27 Color Day program Thursday • Eight enter Ursinus for Spring term • Forum to feature Indian editor at next session • Speak Easy title of Ruby show • TV auditions slated • 3 graduate school test dates released • Ursinus to enter competition in intercollegiate bridge • Dr. Miller to give IRC summary of Department of State conferences attended in recent weeks • Washington trip planned by PAC • Meistersingers give concert • Editorial: Attend forums? • Senior class discusses Ruby and after-game record dance • Red Cross to organize • Juniors discuss bands • French Club to present dance Wednesday night in music studio • Thespians to discuss play • Dictionary of Folklore and Legend includes work of Dr. Phillips on Pennsylvania Dutch • Behind-scenes Dean handles transcripts, records dating from 1873, in routine work • Men reveal resignation toward draft situation • Alumnae back and Duryea\u27s got \u27em; Grads return in role of preceptresses • Coach Seeders drives Bruins toward coveted Middle Atlantic championship • Grizzlies win and lose in non-league contests • Bears edge Blue Hens for loop lead, 62-60 • Mermaids triumph over Drexel, 35-22 • Belles bag first over Bryn Mawr • Brodbeck I & II, Stine lead • Dr. Baker chooses poetry of A. E. Housman for readinghttps://digitalcommons.ursinus.edu/weekly/1558/thumbnail.jp

The Ursinus Weekly, February 12, 1951

New high set by B-list group as 106 qualify • Y schedules chats, conducts retreat • Paynter-Keller production scores hit in Curtain Club group presentation • Play contest in progress; May Day heads named • Alumna to speak at girls\u27 Color Day program Thursday • Eight enter Ursinus for Spring term • Forum to feature Indian editor at next session • Speak Easy title of Ruby show • TV auditions slated • 3 graduate school test dates released • Ursinus to enter competition in intercollegiate bridge • Dr. Miller to give IRC summary of Department of State conferences attended in recent weeks • Washington trip planned by PAC • Meistersingers give concert • Editorial: Attend forums? • Senior class discusses Ruby and after-game record dance • Red Cross to organize • Juniors discuss bands • French Club to present dance Wednesday night in music studio • Thespians to discuss play • Dictionary of Folklore and Legend includes work of Dr. Phillips on Pennsylvania Dutch • Behind-scenes Dean handles transcripts, records dating from 1873, in routine work • Men reveal resignation toward draft situation • Alumnae back and Duryea\u27s got \u27em; Grads return in role of preceptresses • Coach Seeders drives Bruins toward coveted Middle Atlantic championship • Grizzlies win and lose in non-league contests • Bears edge Blue Hens for loop lead, 62-60 • Mermaids triumph over Drexel, 35-22 • Belles bag first over Bryn Mawr • Brodbeck I & II, Stine lead • Dr. Baker chooses poetry of A. E. Housman for readinghttps://digitalcommons.ursinus.edu/weekly/1558/thumbnail.jp

Universality of the excess number of clusters and the crossing probability function in three-dimensional percolation

Extensive Monte-Carlo simulations were performed to evaluate the excess number of clusters and the crossing probability function for three-dimensional percolation on the simple cubic (s.c.), face-centered cubic (f.c.c.), and body-centered cubic (b.c.c.) lattices. Systems L x L x L' with L' >> L were studied for both bond (s.c., f.c.c., b.c.c.) and site (f.c.c.) percolation. The excess number of clusters $\tilde {b}$ per unit length was confirmed to be a universal quantity with a value $\tilde {b} \approx 0.412$. Likewise, the critical crossing probability in the L' direction, with periodic boundary conditions in the L x L plane, was found to follow a universal exponential decay as a function of r = L'/L for large r. Simulations were also carried out to find new precise values of the critical thresholds for site percolation on the f.c.c. and b.c.c. lattices, yielding $p_c(f.c.c.)= 0.199 236 5 \pm 0.000 001 0$, $p_c(b.c.c.)= 0.245 961 5\pm 0.000 001 0$.Comment: 14 pages, 7 figures, LaTeX, submitted to J. Phys. A: Math. Gen, added references, corrected typo

The ‘‘ICE’’ Study: Feasibility of Inexpensive Commercial Coolers on Mobile EMS Units

Introduction: Prehospital postresuscitation induced hypothermia (IH) has been shown to reduce neurological complications in comatose cardiac-arrest survivors. Retrofitting ambulances to include equipment appropriate to initiate hypothermia, such as refrigeration units for cooled saline, is expensive. The objective of this nonhuman subject research study was to determine if inexpensive, commercially available coolers could, in conjunction with five reusable ice packs, keep two 1 L bags of precooled 0.9% normal saline solution (NSS) at or below 48C for an average shift of eight to 12 hours in a real-world environment, on board in-service Emergency Medical Service (EMS) units, over varying weather conditions in all seasons. Methods: The coolers were chosen based on availability and affordability from two nationally available brands: The Igloo MaxxCold (Igloo Products Corp., Katy, Texas USA) and Coleman (The Coleman Company, Wichita, Kansas USA). Both are 8.5 liter (nine-quart) coolers that were chosen because they adequately held two 1 L bags of saline solution, along with the reusable ice packs designated in the study design, and were small enough for ease of placement on ambulances. Initial testing of the coolers was conducted in a controlled environment. Thereafter, each EMS unit was responsible to cool the saline to less than 48C prior to shift. Data were collected by emergency medical technicians, paramedics, and resident physicians working in seven different ambulance squads. Data analysis was performed using repeated measurements recorded over a 12-hour period from 19 individual coolers and were summarized by individual time points using descriptive statistics. Results: Initial testing determined that the coolers maintained temperatures of 48C for 12 hours in a controlled environment. On the ambulances, results based on the repeated measurements over time revealed that the saline solution samples as defined in the protocol, remained consistently below 48C for 12 hours. Utilizing the lower bound of the 2- sided 95% exact binomial confidence intervals, there was less than a five percent chance that saline samples could not be maintained below 48C for 12 hours, even during the summer months. Conclusions: Simple, commercially available coolers can maintain two 1 L bags of 0.9% NSS at 48C for 12 hours in ambulances in varying environmental conditions. This suggests that EMS agencies could inexpensively initiate prehospital IH in appropriate cases

The Factory and The Beehive I. Rotation Periods For Low-Mass Stars in Praesepe

Stellar rotation periods measured from single-age populations are critical for investigating how stellar angular momentum content evolves over time, how that evolution depends on mass, and how rotation influences the stellar dynamo and the magnetically heated chromosphere and corona. We report rotation periods for 40 late-K to mid-M stars members of the nearby, rich, intermediate-age (~600 Myr) open cluster Praesepe. These rotation periods were derived from ~200 observations taken by the Palomar Transient Factory of four cluster fields from 2010 February to May. Our measurements indicate that Praesepe's mass-period relation transitions from a well-defined singular relation to a more scattered distribution of both fast and slow rotators at ~0.6 Msun. The location of this transition is broadly consistent with expectations based on observations of younger clusters and the assumption that stellar-spin down is the dominant mechanism influencing angular momentum evolution at 600 Myr. However, a comparison to data recently published for the Hyades, assumed to be coeval to Praesepe, indicates that the divergence from a singular mass-period relation occurs at different characteristic masses, strengthening the finding that Praesepe is the younger of the two clusters. We also use previously published relations describing the evolution of rotation periods as a function of color and mass to evolve the sample of Praesepe periods in time. Comparing the resulting predictions to periods measured in M35 and NGC 2516 (~150 Myr) and for kinematically selected young and old field star populations suggests that stellar spin-down may progress more slowly than described by these relations.Comment: To appear in the ApJ. 18 pages, 12 figures; version with higher resolution figures available at http://www.astro.columbia.edu/~marcel/papers/praesepe.pdf. Paper title inspired by local news; see http://tinyurl.com/redhone

Near and Mid-IR Photometry of the Pleiades, and a New List of Substellar Candidate Members

We make use of new near and mid-IR photometry of the Pleiades cluster in order to help identify proposed cluster members. We also use the new photometry with previously published photometry to define the single-star main sequence locus at the age of the Pleiades in a variety of color-magnitude planes. The new near and mid-IR photometry extend effectively two magnitudes deeper than the 2MASS All-Sky Point Source catalog, and hence allow us to select a new set of candidate very low mass and sub-stellar mass members of the Pleiades in the central square degree of the cluster. We identify 42 new candidate members fainter than Ks =14 (corresponding to 0.1 Mo). These candidate members should eventually allow a better estimate of the cluster mass function to be made down to of order 0.04 solar masses. We also use new IRAC data, in particular the images obtained at 8 um, in order to comment briefly on interstellar dust in and near the Pleiades. We confirm, as expected, that -- with one exception -- a sample of low mass stars recently identified as having 24 um excesses due to debris disks do not have significant excesses at IRAC wavelengths. However, evidence is also presented that several of the Pleiades high mass stars are found to be impacting with local condensations of the molecular cloud that is passing through the Pleiades at the current epoch.Comment: Accepted to ApJS; data tables and embedded-figure version available at http://spider.ipac.caltech.edu/staff/stauffer/pleiades07