Electromagnetic follow-up of gravitational wave transient signal candidates

Pioneering efforts aiming at the development of multi-messenger gravitational wave and electromagnetic astronomy have been made. An electromagnetic observation follow-up program of candidate gravitational wave events has been performed (Dec 17 2009 to Jan 8 2010 and Sep 4 to Oct 20 2010) during the recent runs of the LIGO and Virgo gravitational wave detectors. It involved ground-based and space electromagnetic facilities observing the sky at optical, X-ray and radio wavelengths. The joint gravitational wave and electromagnetic observation study requires the development of specific image analysis procedures able to discriminate the possible electromagnetic counterpart of gravitational wave triggers from contaminant/background events. The paper presents an overview of the electromagnetic follow-up program and the image analysis procedures.Comment: Proceedings of the 12th International Conference on "Topics in Astroparticle and Underground Physics" (TAUP 2011), Munich, September 2011 (to appear in IoP Journal of Physics: Conference Series

Localizing gravitational wave sources with optical telescopes and combining electromagnetic and gravitational wave data

Neutron star binaries, which are among the most promising sources for the direct detection of gravitational waves (GW) by ground based detectors, are also potential electromagnetic (EM) emitters. Gravitational waves will provide a new window to observe these events and hopefully give us glimpses of new astrophysics. In this paper, we discuss how EM information of these events can considerably improve GW parameter estimation both in terms of accuracy and computational power requirement. And then in return how GW sky localization can help EM astronomers in follow-up studies of sources which did not yield any prompt emission. We discuss how both EM source information and GW source localization can be used in a framework of multi-messenger astronomy. We illustrate how the large error regions in GW sky localizations can be handled in conducting optical astronomy in the advance detector era. We show some preliminary results in the context of an array of optical telescopes called BlackGEM, dedicated for optical follow-up of GW triggers, that is being constructed in La Silla, Chile and is expected to operate concurrent to the advanced GW detectors.Comment: 8 pages, 8 figures, Proceeding for Sant Cugat Forum for Astrophysic

An all-sky search algorithm for continuous gravitational waves from spinning neutron stars in binary systems

Rapidly spinning neutron stars with non-axisymmetric mass distributions are expected to generate quasi-monochromatic continuous gravitational waves. While many searches for unknown, isolated spinning neutron stars have been carried out, there have been no previous searches for unknown sources in binary systems. Since current search methods for unknown, isolated neutron stars are already computationally limited, expanding the parameter space searched to include binary systems is a formidable challenge. We present a new hierarchical binary search method called TwoSpect, which exploits the periodic orbital modulations of the continuous waves by searching for patterns in doubly Fourier-transformed data. We will describe the TwoSpect search pipeline, including its mitigation of detector noise variations and corrections for Doppler frequency modulation caused by changing detector velocity. Tests on Gaussian noise and on a set of simulated signals will be presented.Comment: 22 pages, 10 figures, 1 table, Submitted to Classical and Quantum Gravit

Metagenomic approaches reveal differences in genetic diversity and relative abundance of nitrifying bacteria and archaea in contrasting soils

The abundance and phylogenetic diversity of functional genes involved in nitrification were assessed in Rothamsted soils under contrasting management regimes - permanent bare fallow, grassland and arable (wheat) cultivation maintained for more than 50 years. Metagenome and metatranscriptome analysis indicated that nitrite oxidizing bacteria (NOB) were more abundant than ammonia oxidizing archaea (AOA) and bacteria (AOB) in all soils. The most abundant AOA and AOB in the metagenomes were, respectively, Nitrososphaera and Ca. Nitrososcosmicus (family Nitrososphaeraceae) and Nitrosospira and Nitrosomonas (family Nitrosomonadaceae). The most abundant NOB were Nitrospira including the comammox species Nitrospira inopinata, Ca. N. nitrificans and Ca. N. nitrosa. Anammox bacteria were also detected. Nitrospira and the AOA Nitrososphaeraceae showed most transcriptional activity in arable soil. Similar numbers of sequences were assigned to the amoA genes of AOA and AOB, highest in the arable soil metagenome and metatranscriptome. The AOB amoA reads included those from comammox Nitrospira clades A and B, in addition to Nitrosomonadaceae. Nitrification potential assessed in soils amended or not with DCD (an inhibitor of AOB but not AOA) was highest in arable soils and lower in all soil microcosm assays containing DCD, indicating AOB were responsible for oxidizing ammonium fertilizer added to these soils

Train Like an Astronaut Educational Outreach

In an effort to reduce the incidence of childhood obesity, the National Aeronautics and Space Administration (NASA), capitalizing on the theme of human spaceflight developed two educational outreach programs for children ages 8-12. To motivate young "fit explorers," the Train Like an Astronaut National (TLA) program and the Mission X: Train Like an Astronaut International Fitness Challenge (MX) were created. Based on the astronauts' physical training, these programs consist of activities developed by educators and experts in the areas of space life sciences and fitness. These Activities address components of physical fitness. The educational content hopes to promote students to pursue careers in science, technology, engineering, and math (STEM) fields. At the national level, in partnership with First Lady Michelle Obama's Let?s Move! Initiative, the TLA program consists of 10 physical and 2 educational activities. The program encourages families, schools, and communities to work collaboratively in order to reinforce in children and their families the importance of healthy lifestyle habits In contrast, the MX challenge is a cooperative outreach program involving numerous space agencies and other international partner institutions. During the six-week period, teams of students from around the world are challenged to improve their physical fitness and collectively accumulate points by completing 18 core activities. During the 2011 pilot year, a t otal of 137 teams and more than 4,000 students from 12 countries participated in the event. MX will be implemented within 24 countries during the 2012 challenge. It is projected that 7,000 children will "train like an astronaut"

Nasal carriage of Staphylococcus aureus in dairy sheep.

International audienceThe purpose of this study was to assess the prevalence of Staphylococcus aureus nasal carriage of dairy sheep in farms producing cheeses manufactured with raw ewe's milk. The study showed that 29% of ewes carried S. aureus in their nares. The genetic diversity of the 136 isolates recovered from the anterior nares of the ewes, from the ambient air of the milking parlour and from cheeses was investigated using pulsed-field gel electrophoresis (PFGE) of DNA SmaI digests. The genotyping results showed that 75 out of 106 isolates recovered from nasal carriage in dairy sheep belonged to a dominant pattern (previously named OV) and a genetically related pattern (named OV'). The same profile (OV or OV') was found in the ambient air and cheeses, suggesting a continuum between isolates within these different compartments

Calibration of the LIGO displacement actuators via laser frequency modulation

We present a frequency modulation technique for calibration of the displacement actuators of the LIGO 4-km-long interferometric gravitational-wave detectors. With the interferometer locked in a single-arm configuration, we modulate the frequency of the laser light, creating an effective length variation that we calibrate by measuring the amplitude of the frequency modulation. By simultaneously driving the voice coil actuators that control the length of the arm cavity, we calibrate the voice coil actuation coefficient with an estimated 1-sigma uncertainty of less than one percent. This technique enables a force-free, single-step actuator calibration using a displacement fiducial that is fundamentally different from those employed in other calibration methods.Comment: 10 pages, 5 figures, submitted to Classical and Quantum Gravit

Synthesis of block copolymers of varying architecture through suppression of transesterification during coordinated anionic ring opening polymerization

Well-defined di-and triblock copolymers consisting of ε-caprolactone (CL), L-lactide (LA), and trimethylene carbonate (TMC) were synthesized via "PLA first route" in coordinated anionic ring opening polymerization/copolymerization (CAROP) with tin (II) octoate as catalyst. The desired block structure was preserved by use of protective additive α-methylstyrene by preventing the transesterification side-reactions. MALDI-TOF analysis revealed that the protection mechanism is associated with α-methylstyrene and tin (II) octoate complexation. Additionally, it was shown that use of α-methylstyrene in ring opening polymerization allowed the formation of polyesters with high molar mass

Recreational Marijuana Laws and Junk Food Consumption: Evidence Using Border Analysis and Retail Sales Data

We use retail scanner data on purchases of high calorie food to study the link between recreational marijuana laws (RMLs) and consumption of high calorie food. To do this we exploit differences in the timing of introduction of marijuana laws among states and find that they are complements. Specifically, in counties located in RML states, monthly sales of high calorie food increased by 3.1 percent for ice cream, 4.1 for cookies, and 5.3 percent for chips. Results are robust to including placebo effective dates for RMLs in treated states as well as when using synthetic control methods as an alternative methodology