Identification of a Likely Radio Counterpart of the Rapid Burster

We have identified a likely radio counterpart to the low-mass X-ray binary MXB 1730-335 (the Rapid Burster). The counterpart has shown 8.4 GHz radio on/off behavior correlated with the X-ray on/off behavior as observed by the RXTE/ASM during six VLA observations. The probability of an unrelated, randomly varying background source duplicating this behavior is 1-3% depending on the correlation time scale. The location of the radio source is RA 17h 33m 24.61s; Dec -33d 23' 19.8" (J2000), +/- 0.1". We do not detect 8.4 GHz radio emission coincident with type II (accretion-driven) X-ray bursts. The ratio of radio to X-ray emission during such bursts is constrained to be below the ratio observed during X-ray persistent emission at the 2.9-sigma level. Synchrotron bubble models of the radio emission can provide a reasonable fit to the full data set, collected over several outbursts, assuming that the radio evolution is the same from outburst to outburst, but given the physical constraints the emission is more likely to be due to ~hour-long radio flares such as have been observed from the X-ray binary GRS 1915+105.Comment: 28 pages, 4 figures; accepted for publication in ApJ (no changes

Identification of a Likely Radio Counterpart to the Rapid Burster

We have identified a likely radio counterpart to the low-mass X-ray binary MXB 1730-335 (the Rapid Burster). The counterpart has shown 8.4 GHz radio on/off behavior correlated with the X-ray on/off behavior as observed by the RXTE/ASM during six VLA observations. The probability of an unrelated, randomly varying background source duplicating this behavior is 1%-3% depending on the correlation timescale. The location of the radio source is R.A. 17^h33^m24^s.61, decl. -33°23'19".8 (J2000), ±0".1. We do not detect 8.4 GHz radio emission coincident with type II (accretion-driven) X-ray bursts. The ratio of radio to X-ray emission during such bursts is constrained to be below the ratio observed during X-ray-persistent emission at the 2.9 σ level. Synchrotron bubble models of the radio emission can provide a reasonable fit to the full data set, collected over several outbursts, assuming that the radio evolution is the same from outburst to outburst but given the physical constraints the emission is more likely to be due to ~1 hr radio flares such as have been observed from the X-ray binary GRS 1915+105

Discovery of potent kisspeptin antagonists delineate physiological mechanisms of gonadotropin regulation

Neurons that produce gonadotropin-releasing hormone (GnRH) are the final common pathway by which the brain regulates reproduction. GnRH neurons are regulated by an afferent network of kisspeptin-producing neurons. Kisspeptin binds to its cognate receptor on GnRH neurons and stimulates their activity, which in turn provides an obligatory signal for GnRH secretion—thus gating down-stream events supporting reproduction. We have developed kisspeptin antagonists to facilitate the direct determination of the role of kisspeptin neurons in the neuroendocrine regulation of reproduction. In vitro and in vivo studies of analogues of kisspeptin-10 with amino substitutions have identified several potent and specific antagonists. A selected antagonist was shown to inhibit the firing of GnRH neurons in the brain of the mouse and to reduce pulsatile GnRH secretion in female pubertal monkeys; the later supporting a key role of kisspeptin in puberty onset. This analogue also inhibited the kisspeptin-induced release of luteinizing hormone (LH) in rats and mice and blocked the post-castration rise in LH in sheep, rats and mice, suggesting that kisspeptin neurons mediate the negative feedback effect of sex steroids on gonadotropin secretion in mammals. The development of kisspeptin antagonists provides a valuable tool for investigating the physiological and pathophysiological roles of kisspeptin in the regulation of reproduction and could offer a unique therapeutic agent for treating hormone-dependent disorders of reproduction, including precocious puberty, endometriosis, and metastatic prostate cancer

Sexual Orientation and Household Decision Making: Same-Sex Couples' Balance of Power and Labor Supply Choices

I estimate how intra-household bargaining affects gay and lesbian couples' labor supplies, investigating their similarity to heterosexual decision-making, in a collective household framework. Data from the 2000 US Census show that couples of all types exhibit a significant response to bargaining power shifts, as measured by differences between partners in age or non-labor income. In gay, lesbian, and heterosexual cohabiting couples, a relatively young or rich partner has more bargaining power and hence supplies less labor, the opposite holding for his/her mate. Married couples value the older spouse instead, or the richer. No effects are found for same-sex roommates

Technology Transfer in the Non-Traded Sector as a Means to Combat Global Warming

The paper considers a situation where two countries - the North and the South - use a non-traded polluting input to produce the goods for final consumption. The North is more efficient in both, production and abatement processes. The study compares the effects of the transfer of abatement technology by the North to the South under autarky with the free trade situation, assuming that the North pre-commits to an international protocol to keep the global pollution under a fixed level. The conditions under which either full or partial technology is transferred in autarky are determined. It is shown that under free trade no such transfer is possible. With trade even though the North wants a complete transfer of technology, the South refuses it

Technology Diffusion, Abatement Cost and Transboundary Pollution

This paper studies countries' incentives to develop advanced pollution abatement technology when technology may spillover across countries and pollution abatement is a global public good. We are motivated in part by the problem of global warming: a solution to this involves providing a global public good, and will surely require the development and implementation of new technologies. We show that at the Nash equilibrium of a simultaneous-move game with R&D investment and emission abatement, whether the free rider effect prevails and under-investment and excess emissions occur depends on the degree of technology spillovers and the effect of R&D on the marginal abatement costs. There are cases in which, contrary to conventional wisdom, Nash equilibrium investments in emissions reductions exceed the first-best case

The Relationship between Environmental Efficiency and Manufacturing Firm's Growth

This paper investigates the empirical link between emission intensity and economic growth, using a very large data set of 61,219 Italian manufacturing firms over the period 2000-2004. As a measure of lagged environmental performance (efficiency) at firm level we exploit NAMEA sector for CO2, NOx, SOx data over 1990-1999. The paper tests the extent to which (past) environmental efficiency/intensity, which is driven by structural features and firm strategic actions, including responses to policies, influences firms growth. Our results show, first, a typical trade off generally appearing for the three core environmental emissions we analyse: lower environmentally efficiency in the recent past allows higher degrees of freedom to firms and relax the constraints for growth, at least in this short/medium term scenario. Nevertheless, the size of the estimated coefficients is not large. Trade offs are significant for two emission indicators out of two, but quite negligible in terms of impacts, besides the case of CO2. For example, growth is reduced by far less than 0.1% in association to a 1% increase of environmental efficiency. In addition, non-linearity seems to characterise the economic growth-environmental performance relationship. Signals of inverted U shape appear: this may be a signal that both firm strategies and recent policy efforts are affecting the dynamic relationship between environmental efficiency and economic productivity, turning it from an usual trade off to a possible joint complementary/co-dynamics

Platelets generated from human embryonic stem cells are functional in vitro and in the microcirculation of living mice

Platelets play an essential role in hemostasis and atherothrombosis. Owing to their short storage time, there is constant demand for this life-saving blood component. In this study, we report that it is feasible to generate functional megakaryocytes and platelets from human embryonic stem cells (hESCs) on a large scale. Differential-interference contrast and electron microscopy analyses showed that ultrastructural and morphological features of hESC-derived platelets were indistinguishable from those of normal blood platelets. In functional assays, hESC-derived platelets responded to thrombin stimulation, formed microaggregates, and facilitated clot formation/retraction in vitro. Live cell microscopy demonstrated that hESC-platelets formed lamellipodia and filopodia in response to thrombin activation, and tethered to each other as observed in normal blood. Using real-time intravital imaging with high-speed video microscopy, we have also shown that hESC-derived platelets contribute to developing thrombi at sites of laser-induced vascular injury in mice, providing the first evidence for in vivo functionality of hESC-derived platelets. These results represent an important step toward generating an unlimited supply of platelets for transfusion. Since platelets contain no genetic material, they are ideal candidates for early clinical translation involving human pluripotent stem cells

A Meaningful U.S. Cap-and-Trade System to Address Climate Change

There is growing impetus for a domestic U.S. climate policy that can provide meaningful reductions in emissions of CO2 and other greenhouse gases. In this article, I propose and analyze a scientifically sound, economically rational, and politically feasible approach for the United States to reduce its contributions to the increase in atmospheric concentrations of greenhouse gases. The proposal features an up-stream, economy-wide CO2 cap-and-trade system which implements a gradual trajectory of emissions reductions over time, and includes mechanisms to reduce cost uncertainty. I compare the proposed system with frequently discussed alternatives. In addition, I describe common objections to a cap-and-trade approach to the problem, and provide responses to these objections