Ecto- and Endoparasites of the Texas Deermouse, Peromyscus attwateri and Eastern Woodrat, Neotoma floridana (Rodentia: Cricetidae) from Polk County, Arkansas

In Arkansas, the Texas deermouse (Peromyscus attwateri) occurs in the western part of the state where it is restricted to the uplands of the Interior Highlands. The eastern woodrat (Neotoma floridana) is found statewide but is less common in the Gulf Coastal Plain. Very little is known about the parasites of either rodent in Arkansas, especially helminths from P. attwateri at any locality within its range. Found in/on P. attwateri were a coccidian (Eimeria langbarteli), a tapeworm (Catenotaenia peromysci), a nematode (Syphacia peromysci), 2 ticks (Dermacenter variabilis and Ixodes scapularis), and 2 mites (Androlaelaps fahrenholzi and Leptotrombidium peromysci). Eastern woodrats harbored 3 nematodes (Eucoelus sp., Longistriata neotoma, and Trichurus neotomae), a larval bot fly (Cuterebra americana), and a flea (Orchopeas pennsylvanicus). We document 6 new host and 5 new distributional records for these parasites

Eimeria lancasterensis (Apicomplexa: Eimeriidae), Three Nematodes (Heligmosomoidea: Boehmiellidae, Heligmonellidae), and a Flea (Siphonaptera: Ceratophyllidae) from the Eastern Fox Squirrel, Sciurus niger (Rodentia: Sciuridae) in Arkansas

In Arkansas, the eastern fox squirrel (Sciurus niger) is a common inhabitant of the state. Although information is available on ectoparasites of this host in Arkansas, little is known about the endoparasites of this squirrel. A single specimen from Montgomery County was examined and found to harbor the following: a coccidian (Eimeria lancasterensis), three nematodes, Boehmiella wilsoni, Citellinema bifurcatum, and Sciurodendrium hassalli, and a flea, Orchopeas howardi. We document these nematodes from an Arkansas S. niger for the first time, and add mensural and molecular information on E. lancasterensis from this host

H3K36 Methylation Promotes Longevity by Enhancing Transcriptional Fidelity

Epigenetic mechanisms, including histone post-translational modifications, control longevity in diverse organisms. Relatedly, loss of proper transcriptional regulation on a global scale is an emerging phenomenon of shortened life span, but the specific mechanisms linking these observations remain to be uncovered. Here, we describe a life span screen in Saccharomyces cerevisiae that is designed to identify amino acid residues of histones that regulate yeast replicative aging. Our results reveal that lack of sustained histone H3K36 methylation is commensurate with increased cryptic transcription in a subset of genes in old cells and with shorter life span. In contrast, deletion of the K36me2/3 demethylase Rph1 increases H3K36me3 within these genes, suppresses cryptic transcript initiation, and extends life span. We show that this aging phenomenon is conserved, as cryptic transcription also increases in old worms. We propose that epigenetic misregulation in aging cells leads to loss of transcriptional precision that is detrimental to life span, and, importantly, this acceleration in aging can be reversed by restoring transcriptional fidelity

Upper limits on the strength of periodic gravitational waves from PSR J1939+2134

The first science run of the LIGO and GEO gravitational wave detectors presented the opportunity to test methods of searching for gravitational waves from known pulsars. Here we present new direct upper limits on the strength of waves from the pulsar PSR J1939+2134 using two independent analysis methods, one in the frequency domain using frequentist statistics and one in the time domain using Bayesian inference. Both methods show that the strain amplitude at Earth from this pulsar is less than a few times $10^{-22}$.Comment: 7 pages, 1 figure, to appear in the Proceedings of the 5th Edoardo Amaldi Conference on Gravitational Waves, Tirrenia, Pisa, Italy, 6-11 July 200

Improving the sensitivity to gravitational-wave sources by modifying the input-output optics of advanced interferometers

We study frequency dependent (FD) input-output schemes for signal-recycling interferometers, the baseline design of Advanced LIGO and the current configuration of GEO 600. Complementary to a recent proposal by Harms et al. to use FD input squeezing and ordinary homodyne detection, we explore a scheme which uses ordinary squeezed vacuum, but FD readout. Both schemes, which are sub-optimal among all possible input-output schemes, provide a global noise suppression by the power squeeze factor, while being realizable by using detuned Fabry-Perot cavities as input/output filters. At high frequencies, the two schemes are shown to be equivalent, while at low frequencies our scheme gives better performance than that of Harms et al., and is nearly fully optimal. We then study the sensitivity improvement achievable by these schemes in Advanced LIGO era (with 30-m filter cavities and current estimates of filter-mirror losses and thermal noise), for neutron star binary inspirals, and for narrowband GW sources such as low-mass X-ray binaries and known radio pulsars. Optical losses are shown to be a major obstacle for the actual implementation of these techniques in Advanced LIGO. On time scales of third-generation interferometers, like EURO/LIGO-III (~2012), with kilometer-scale filter cavities, a signal-recycling interferometer with the FD readout scheme explored in this paper can have performances comparable to existing proposals. [abridged]Comment: Figs. 9 and 12 corrected; Appendix added for narrowband data analysi

The medical student

The Medical Student was published from 1888-1921 by the students of Boston University School of Medicine

Protistan Diversity in the Arctic: A Case of Paleoclimate Shaping Modern Biodiversity?

The impact of climate on biodiversity is indisputable. Climate changes over geological time must have significantly influenced the evolution of biodiversity, ultimately leading to its present pattern. Here we consider the paleoclimate data record, inferring that present-day hot and cold environments should contain, respectively, the largest and the smallest diversity of ancestral lineages of microbial eukaryotes.We investigate this hypothesis by analyzing an original dataset of 18S rRNA gene sequences from Western Greenland in the Arctic, and data from the existing literature on 18S rRNA gene diversity in hydrothermal vent, temperate sediments, and anoxic water column communities. Unexpectedly, the community from the cold environment emerged as one of the richest observed to date in protistan species, and most diverse in ancestral lineages.This pattern is consistent with natural selection sweeps on aerobic non-psychrophilic microbial eukaryotes repeatedly caused by low temperatures and global anoxia of snowball Earth conditions. It implies that cold refuges persisted through the periods of greenhouse conditions, which agrees with some, although not all, current views on the extent of the past global cooling and warming events. We therefore identify cold environments as promising targets for microbial discovery