Polarized synchrotron emission in quiescent black hole X-ray transients

We present near-infrared polarimetric observations of the black hole X-ray binaries Swift J1357.2-0933 and A0620-00. In both sources, recent studies have demonstrated the presence of variable infrared synchrotron emission in quiescence, most likely from weak compact jets. For Swift J1357.2-0933 we find that the synchrotron emission is polarized at a level of 8.0 +- 2.5 per cent (a 3.2 sigma detection of intrinsic polarization). The mean magnitude and rms variability of the flux (fractional rms of 19-24 per cent in K_s-band) agree with previous observations. These properties imply a continuously launched (stable on long timescales), highly variable (on short timescales) jet in the Swift J1357.2-0933 system in quiescence, which has a moderately tangled magnetic field close to the base of the jet. We find that for A0620-00, there are likely to be three components to the optical-infrared polarization; interstellar dust along the line of sight, scattering within the system, and an additional source that changes the polarization position angle in the reddest (H and K_s) wave-bands. We interpret this as a stronger contribution of synchrotron emission, and by subtracting the line-of-sight polarization, we measure an excess of ~ 1.25 +- 0.28 per cent polarization and a position angle of the magnetic field vector that is consistent with being parallel with the axis of the resolved radio jet. These results imply that weak jets in low luminosity accreting systems have magnetic fields which possess similarly tangled fields compared to the more luminous, hard state jets in X-ray binaries.Comment: Accepted to MNRA

Alien Registration- Fraser, David M. (Lewiston, Androscoggin County)

https://digitalmaine.com/alien_docs/29756/thumbnail.jp

Robotic Astronomy with the Faulkes Telescopes and Las Cumbres Observatory Global Telescope

We present results from ongoing science projects conducted by members of the Faulkes Telescope (FT) team and Las Cumbres Observatory Global Telescope (LCOGT). Many of these projects incorporate observations carried out and analysed by FT users, comprising amateur astronomers and schools. We also discuss plans for the further development of the LCOGT network.Comment: 8 pages, 2 figures, conference proceedings from "Workshop on Robotic Autonomous Observatories", held at Malaga, Spain from 18-21 May 2009, acccepted for publication in Advances in Astronom

Micrococcal Nuclease Does Not Substantially Bias Nucleosome Mapping

We have mapped sequence-directed nucleosome positioning on genomic DNA molecules using high-throughput sequencing. Chromatins, prepared by reconstitution with either chicken or frog histones, were separately digested to mononucleosomes using either micrococcal nuclease (MNase) or caspase-activated DNase (CAD). Both enzymes preferentially cleave internucleosomal (linker) DNA, although they do so by markedly different mechanisms. MNase has hitherto been very widely used to map nucleosomes, although concerns have been raised over its potential to introduce bias. Having identified the locations and quantified the strength of both the chicken or frog histone octamer binding sites on each DNA, the results obtained with the two enzymes were compared using a variety of criteria. Both enzymes displayed sequence specificity in their preferred cleavage sites, although the nature of this selectivity was distinct for the two enzymes. In addition, nucleosomes produced by CAD nuclease are 8–10 bp longer than those produced with MNase, with the CAD cleavage sites tending to be 4–5 bp further out from the nucleosomal dyad than the corresponding MNase cleavage sites. Despite these notable differences in cleavage behaviour, the two nucleases identified essentially equivalent patterns of nucleosome positioning sites on each of the DNAs tested, an observation that was independent of the histone type. These results indicate that biases in nucleosome positioning data collected using MNase are, under our conditions, not significant

Continued monitoring of LMXBs with the Faulkes Telescopes

The Faulkes Telescope Project is an educational and research arm of the Las Cumbres Observatory Global Telescope Network (LCOGTN). It has two 2-metre robotic telescopes, located at Haleakala on Maui (FT North) and Siding Spring in Australia (FT South). It is planned for these telescopes to be complemented by a research network of eighteen 1-metre telescopes, along with an educational network of twenty-eight 0.4-metre telescopes, providing 24 hour coverage of both northern and southern hemispheres. We have been conducting a monitoring project of 13 low-mass X-ray binaries (LMXBs) using FT North since early 2006. The introduction of FT South has allowed us to extend this to monitor a total of 30 LMXBs (see target list, Section 4). New instrumentation will allow us to expand this project to include both infrared wavelengths (z and y band) and spectroscopy. Brighter targets (~ 16 - 18 mag.) are imaged weekly in V, R and i’ bands (SNR ~ 50), while fainter ones (> 18 mag.) are observed only in i’ band (SNR ~ 20). We alter this cadence in response to our own analysis or Astronomers Telegrams (ATels)

Vocal Response of Piglets to Weaning: Effect of Piglet Age

Piglets vocalize a great deal during the first few days after weaning. The aim of this experiment was to determine if the calls given by piglets vary in response to one factor thought to influence post-weaning adaptation: weaning age. In 22 litters, each containing a minimum of 9 piglets, 3 piglets were weaned under identical conditions at 3, 4 and 5 weeks of age. Vocalizations and weight gain were monitored for the week after weaning. The number of calls produced by piglets of all three ages declined from an average of 8.2 calls/min per piglet on the day of weaning to only 1.6 calls/min 4 days later. Overall, piglets weaned at younger ages called more (P \u3c 0.001): piglets weaned at 3 weeks produced an average of 3.6 calls/min during the week after weaning, while those weaned at 4 and 5 weeks produced 2.9 and 2.3 calls/min respectively. The average frequency of the calls also fell (P \u3c 0.001), from 441 Hz for piglets weaned at 3 weeks of age to 384 Hz for those weaned at 5 weeks. These results suggest that vocalizations can be useful for monitoring post-weaning adaptation in piglets

Calling by Domestic Piglets: Reliable Signals of Need?

Two manipulations were performed on domestic piglets to determine whether differences in calling during periods of separation from the mother can indicate differences in need. In both cases, the aim was to manipulate the piglet\u27s need for the sow\u27s attention. In the first manipulation a \u27thriving\u27 piglet (i.e. the piglet with the heaviest weight and most rapid weight gain) and a \u27non-thriving\u27 one (lightest and slowest weight gain) were selected from each of 15 litters. The two piglets were removed from the sow and litter and recorded for 13 min in separate isolated enclosures. For the second manipulation, two piglets of intermediate weight and weight gain were selected from each of the same 15 litters, and were removed from the sow during nursing under one of two conditions. The \u27unfed\u27 piglet was removed just before the milk ejection and the \u27fed\u27 one just after receiving milk. Both were recorded as in the first manipulation. \u27Non-thriving\u27 and \u27unfed\u27 piglets called more and used more high-frequency calls, longer calls, and calls that rose more in frequency than their \u27thriving\u27 and \u27fed\u27 litter-mates. By means of a playback experiment, the assumption that sows respond to these piglet calls was tested. Sows were more likely to vocalize and approach the loudspeaker during playback of the piglet isolation calls than during playback of white noise. It is argued that if a piglet\u27s calls provide reliable information about its need for the sow\u27s resources, then this calling can be used as a measure of its welfare. These results are consistent with theoretical models of honest signalling

Partial Tooth-Clipping of Suckling Pigs: Effects on Neonatal Competition and Facial Injuries

Piglets are born with fully erupted ‘needle teeth’ which are used in competition for access to teats. Producers often clip these teeth to the gum line soon after birth to avoid any resulting facial lacerations, but this clipping can itself lead to injury or infection. Two experiments investigated the effects on facial injury and piglet performance of the potentially less damaging practice of ‘partial clipping’ whereby only the distal third of the tooth is removed. In Experiment 1, teeth were (1) partially clipped, (2) fully clipped to the gum line, or (3) left intact. All piglets of a litter received one treatment on one side of the mouth and a different treatment on the other side, with the three treatments balanced over the two sides in different litters. Facial lesions, scored separately for the two sides of the face at 3, 7, and 14 days, were negligible on the side facing either partially clipped or fully clipped teeth, but lesions on the side facing intact teeth were significantly greater (P \u3c 0.02). In Experiment 2, some piglets in each of 22 litters had their teeth partially clipped, fully clipped, or left intact. In the first week after birth, piglets with fully clipped teeth gained the least (132 ± 6 g/day), those with partially clipped teeth were intermediate (144 ± 7), and those with intact teeth gained the most (154 ± 7; P \u3c 0.02). There was no significant effect of treatment on later weight gain, the number of piglet deaths, or piglet suckling position (anterior to posterior). Thus, teeth that were partially clipped appeared to have a slight effect in competition among litter-mates, but caused little injury to other piglets

The Road Effect Zone GIS Model

The numerous effects roads have on the surrounding environment were investigated and geographically modeled. Several of these effects were then isolated and looked at in greater detail, developing a model that represents the various interactions between a road and the surrounding region. These road effects could be expressed in a GIS (geographic information system) environment, based on user-inputs. A traffic noise model was used to estimate the extent and intensity of this road effect. Environmental attributes were also summarized within the traffic noise effect zone as an example of evaluation of road effects useful during early transportation planning. The model was designed to be a proof-of-concept of a standalone tool for environmental and transportation planners in local and state agencies