Chance Estimations for Detecting Gravitational Waves with LIGO/Virgo Associated with Gamma Ray Bursts

Short Gamma Ray Bursts (SGRB) are believed to originate from the merger of two compact objects. If this scenario is correct, SGRB will be accompanied by the emission of strong gravitational waves, detectable by current or planned GW detectors, such as LIGO and Virgo. No detection of a gravitational wave has been made up to date. In this paper I will use a set of SGRB with observed redshifts to fit a model describing the cumulative number of SGRB as a function of redshift, to determine the rate of such merger events in the nearby universe. These estimations will be used to make probability statements about detecting a gravitational wave associated with a short gamma ray burst during the latest science run of LIGO/Virgo. Chance estimations for the enhanced and advanced detectors will also be made, and a comparison between the rates deduced from this work will be compared to the existing literature.Comment: 17 pages, 8 figure

Economic Migration, Networks and Human Capital Transferability from the New European Borderlands. A Comparison of Five Eastern European Countries.

In the paper we use a unique new data set which has been collected in late 2006 in Armenia, Belarus, Georgia, Moldova and Ukraine to investigate the determinants for short term migration and its destination and duration patterns. Special attention is paid to the role played by personal networks to Eastern and Western destinations as well as investments into the transferability of human capital made by migrants prior to their stay abroad. We find that many determinants and migration patterns are quite similar across the CIS countries under consideration but exhibit some surprising differences to standard results from the migration literature, e.g. the prevalence of older migrants and the low importance of children in the migration decision process. Networks and human capital transferability are the main explaining factors for the migration and destination decision, a result proofing robust after correcting for endogeneity. We expect that migration is likely to grow in importance for some countries at the European Borderlands, as networks develop and the costs of migration decrease. However, our analysis reveals that fears of brain drain have little substance as the educational background of migrants is rather low. As a considerable number of migrants have invested into destination country specific human capital prior to migration, this improved human capital endowment can benefit both, migrants and the society of sending countries, alike. --Migration,human capital transferability,migration networks,cross-country study

Temporary Labour Migration and Welfare at the New European Fringe : A Comparison of Five Eastern European Countries

This paper investigates patterns and determinants of temporary labour migration in Armenia, Belarus, Georgia, Moldova and Ukraine after EU enlargement in 2004. Migration incidence, destination choices and migration determinants differ between poorer and better-off countries. Although broadly in line with general results from the migration literature, we observe some peculiarities like the high share of older migrants and a modest role of family obligations in the migration decision process. We find no indication of a brain drain related to temporary migration in sending regions as the educational background of migrants is rather low. Migration is used as household insurance against unemployment and is associated with lower incidence of poverty. This finding remains robust when attempting to reduce the potential omitted variable bias with an instrumental variable approach.Temporary migration, welfare, Eastern Europe, cross-country study

Temporary Labour Migration and Welfare at the New European Fringe: A Comparison of Five Eastern European Countries

This paper investigates patterns and determinants of temporary labour migration in Armenia, Belarus, Georgia, Moldova and Ukraine after EU enlargement in 2004. Migration incidence, destination choices and migration determinants differ between poorer and better-off countries. Although broadly in line with general results from the migration literature, we observe some peculiarities like the high share of older migrants and a modest role of family obligations in the migration decision process. We find no indication of a brain drain related to temporary migration in sending regions as the educational background of migrants is rather low. Migration is used as household insurance against unemployment and is associated with lower incidence of poverty. This finding remains robust when attempting to reduce the potential omitted variable bias with an instrumental variable approach.temporary migration, welfare, Eastern Europe, cross-country study

Outlook for detection of GW inspirals by GRB-triggered searches in the Advanced detector era

Short, hard gamma-ray bursts (GRBs) are believed to originate from the coalescence of two neutron stars (NSs) or a NS and a black hole (BH). If this scenario is correct, then short GRBs will be accompanied by the emission of strong gravitational waves (GWs), detectable by GW observatories such as LIGO, Virgo, KAGRA, and LIGO-India. As compared with blind, all-sky, all-time GW searches, externally triggered searches for GW counterparts to short GRBs have the advantages of both significantly reduced detection threshold due to known time and sky location and enhanced GW amplitude because of face-on orientation. Based on the distribution of signal-to-noise ratios in candidate compact binary coalescence events in the most recent joint LIGO-Virgo data, our analytic estimates, and our Monte Carlo simulations, we find an effective sensitive volume for GRB-triggered searches that is about 2 times greater than for an all-sky, all-time search. For NS-NS systems, a jet angle of 20 degrees, a gamma-ray satellite field of view of 10% of the sky, and priors with generally precessing spin, this doubles the number of NS-NS short-GRB and NS-BH short-GRB associations, to ~3-4% of all detections of NS-NSs and NS-BHs. We also investigate the power of tests for statistical excesses in lists of subthreshold events, and show that these are unlikely to reveal a subthreshold population until finding GW associations to short GRBs is already routine. Finally, we provide useful formulas for calculating the prior distribution of GW amplitudes from a compact binary coalescence, for a given GW detector network and given sky location.Comment: 14 pages, 4 figures, published in PRD; this version includes changes in final copyedited articl

Novel strategies to improve co-fermentation of pentoses with D-glucose by recombinant yeast strains in lignocellulosic hydrolysates

Economically feasible production of second-generation biofuels requires efficient co-fermentation of pentose and hexose sugars in lignocellulosic hydrolysates under very harsh conditions. Baker’s yeast is an excellent, traditionally used ethanol producer but is naturally not able to utilize pentoses. This is due to the lack of pentose-specific transporter proteins and enzymatic reactions. Thus, natural yeast strains must be modified by genetic engineering. Although the construction of various recombinant yeast strains able to ferment pentose sugars has been described during the last two decades, their rates of pentose utilization is still significantly lower than D-glucose fermentation. Moreover, pentoses are only fermented after D-glucose is exhausted, resulting in an uneconomical increase in the fermentation time. In this addendum, we discuss novel approaches to improve utilization of pentoses by development of specific transporters and substrate channeling in enzyme cascades. Addendum to: T Subtil, E Boles. Competition between pentoses and glucose during uptake and catabolism in recombinant Saccharomyces cerevisiae. Biotechnol Biofuels 2012; 5: 14 PMID: 22424089 DOI: 10.1186/1754-6834-5-1

GRB-triggered searches for gravitational waves in LIGO data

The LIGO gravitational wave detectors have recently reached their design sensitivity and finished a two-year science run. During this period one year of data with unprecedented sensitivity has been collected. I will briefly describe the status of the LIGO detectors and the overall quality of the most recent science run. I also will present results of a search for inspiral waveforms in gravitational wave data coincident with the short gamma ray burst detected on 1st February 2007, with its sky location error box overlapping a spiral arms of M31. No gravitational wave signals were detected and a binary merger in M31 can be excluded at the 99% confidence level.Comment: 5 pages, 3 figures, contributed talk, submitted to the proceedings of Gamma Ray Bursts 2007, Santa Fe, New Mexico, November 5-9 200