Star Cluster Formation and Disruption Time-Scales - II. Evolution of the Star Cluster System in M82's Fossil Starburst

ABRIDGED: We obtain new age and mass estimates for the star clusters in M82's fossil starburst region B, based on improved fitting methods. Our new age estimates confirm the peak in the age histogram attributed to the last tidal encounter with M81; we find a peak formation epoch at slightly older ages than previously published, log(t_peak / yr) = 9.04, with a Gaussian sigma of Delta log(t_width) = 0.273. Cluster disruption has removed a large fraction of the older clusters. Adopting the expression for the cluster disruption time-scale of t_dis(M)= t_dis^4 (M/10^4 Msun)^gamma with gamma = 0.62 (Paper I), we find that the ratios between the real cluster formation rates in the pre-burst phase (log(t/yr) <= 9.4), the burst-phase (8.4 < log(t/yr) < 9.4) and the post-burst phase (log(t/yr) <= 8.4) are about 1:2:1/40. The mass distribution of the clusters formed during the burst shows a turnover at log(M_cl/Msun) ~ 5.3 which is not caused by selection effects. This distribution can be explained by cluster formation with an initial power-law mass function of slope alpha=2 up to a maximum cluster mass of M_max = 3 x 10^6 Msun, and cluster disruption with a normalisation time-scale t_dis^4 / t_burst = (3.0 +/- 0.3) x 10^{-2}. For a burst age of 1 x 10^9 yr, we find that the disruption time-scale of a cluster of 10^4 Msun is t_dis^4 ~ 3 x 10^7 years, with an uncertainty of approximately a factor of two. This is the shortest disruption time-scale known in any galaxy.Comment: 14 pages including 8 postscript figures; accepted for publication in MNRA

An Empirical Analysis of Determinants of Commercial and Industrial Electricity Consumption

The present empirical study focuses on identifying key economic factors and other conditions that have influenced the per customer commercial and industrial consumption of electricity in the U.S. during recent years. Unlike most previous studies, this study uses a state-level panel data set for the period 2002 through 2005. The three panel two-stage least squares (P2SLS) estimates provided in this study imply that per customer commercial and industrial electricity consumption is an increasing function of the annual number of cooling degree days, per capita real disposable income (a de facto “control” variable), and the peak summer electricity generating capacity. Furthermore, per customer commercial and industrial electricity consumption is a decreasing function of the average real unit price of electricity to commercial and industrial enterprises

Recent Evidence on Residential Electricity Consumption Determinants: A Panel Two-Stage Least Squares Analysis, 2001-2005

This empirical study seeks to provide evidence identifying key factors that have influenced per residential customer electricity consumption in the U.S. during recent years. This empirical analysis takes the form of P2SLS (panel two-stage least squares) estimations. State-level data are adopted for the five-year period from 2001 through 2005. The P2SLS findings indicate that the annual consumption of electricity per residential customer is an increasing function of the annual number of cooling degree days, real per capita personal disposable income, and the real unit price of natural gas. Annual per residential customer electricity consumption is also found to be a decreasing function of the real unit price of electricity and the extent of usage of natural gas for residential heating, as well as the degree to which each state has pursued energy efficiency policies. Finally, said consumption is also found to be positively a function of a control variable measuring peak summer electricity generating capacity

An Empirical Analysis of Determinants of Commercial and Industrial Electricity Consumption

The present empirical study focuses on identifying key economic factors and other conditions that have influenced the per customer commercial and industrial consumption of electricity in the U.S. during recent years. Unlike most previous studies, this study uses a state-level panel data set for the period 2002 through 2005. The three panel two-stage least squares (P2SLS) estimates provided in this study imply that per customer commercial and industrial electricity consumption is an increasing function of the annual number of cooling degree days, per capita real disposable income (a de facto “control” variable), and the peak summer electricity generating capacity. Furthermore, per customer commercial and industrial electricity consumption is a decreasing function of the average real unit price of electricity to commercial and industrial enterprises

Increasing impacts of extreme droughts on vegetation productivity under climate change

Terrestrial gross primary production (GPP) is the basis of vegetation growth and food production globally1 and plays a critical role in regulating atmospheric CO2 through its impact on ecosystem carbon balance. Even though higher CO2 concentrations in future decades can increase GPP2, low soil water availability, heat stress and disturbances associated with droughts could reduce the benefits of such CO2 fertilization. Here we analysed outputs of 13 Earth system models to show an increasingly stronger impact on GPP by extreme droughts than by mild and moderate droughts over the twenty-first century. Due to a dramatic increase in the frequency of extreme droughts, the magnitude of globally averaged reductions in GPP associated with extreme droughts was projected to be nearly tripled by the last quarter of this century (2075–2099) relative to that of the historical period (1850–1999) under both high and intermediate GHG emission scenarios. By contrast, the magnitude of GPP reductions associated with mild and moderate droughts was not projected to increase substantially. Our analysis indicates a high risk of extreme droughts to the global carbon cycle with atmospheric warming; however, this risk can be potentially mitigated by positive anomalies of GPP associated with favourable environmental conditions

One Year Follow-up of a Randomized, Double-Blind, Placebo-Controlled Trial of Percutaneous Peripheral Nerve Stimulation for Chronic Neuropathic Pain Following Amputation

Abstract INTRODUCTION Over 85% of patients experience residual limb (RLP) and/or phantom limb (PLP) pain following amputation. Peripheral nerve stimulation (PNS) is a non-opioid approach to relieve postamputation neuropathic pain. A recent multicenter, randomized, double-blind, placebo-controlled study using a novel percutaneous PNS system demonstrated clinically and statistically significant improvements in pain and pain interference with PNS compared to placebo (Gilmore et al, 2019). This work presents prospective 1-yr follow-up to assess durability of pain relief and functional improvements. METHODS Over 85% of patients experience residual limb (RLP) and/or phantom limb (PLP) pain following amputation. Peripheral nerve stimulation (PNS) is a non-opioid approach to relieve post-amputation neuropathic pain. A recent multicenter, randomized, double-blind, placebo-controlled study using a novel percutaneous PNS system demonstrated clinically and statistically significant improvements in pain and pain interference with PNS compared to placebo (Gilmore et al, 2019). This work presents prospective one-year follow-up to assess durability of pain relief and functional improvements. RESULTS A significantly greater proportion of subjects who completed the 12-mo visit reported&nbsp;=&nbsp;50% pain relief on the BPI-SF (5/8, 63%; average pain relief&nbsp;=&nbsp;73% among responders) compared to the placebo group at the time of crossover (0/14, 0%, P&nbsp;=&nbsp;.003; average pain relief&nbsp;=&nbsp;23%). A majority of subjects also reported&nbsp;=&nbsp;50% reductions in pain interference at 12 mo (5/8, 63%). Two of 13 (15%) subjects in the placebo group reported sustained improvements in pain interference (P&nbsp;=&nbsp;.06). Average reduction in pain interference among responders in the PNS group was 87%. CONCLUSION This work suggests that PNS delivered over 60 d may provide clinically significant and enduring pain relief, enabling improved function and potentially reducing the need for a permanently implanted system

InGaP/GaAsHBTsにおける表面欠陥の及ぼす信頼性の問題

電気通信大学200

A Giant Outburst at Millimeter Wavelengths in the Orion Nebula

BIMA observations of the Orion nebula discovered a giant flare from a young star previously undetected at millimeter wavelengths. The star briefly became the brightest compact object in the nebula at 86 GHz. Its flux density increased by more than a factor of 5 on a timescale of hours, to a peak of 160 mJy. This is one of the most luminous stellar radio flares ever observed. Remarkably, the Chandra X-ray observatory was in the midst of a deep integration of the Orion nebula at the time of the BIMA discovery; the source's X-ray flux increased by a factor of 10 approximately 2 days before the radio detection. Follow-up radio observations with the VLA and BIMA showed that the source decayed on a timescale of days, then flared again several times over the next 70 days, although never as brightly as during the discovery. Circular polarization was detected at 15, 22, and 43 GHz, indicating that the emission mechanism was cyclotron. VLBA observations 9 days after the initial flare yield a brightness temperature Tb > 5 x 10^7 K at 15 GHz. Infrared spectroscopy indicates the source is a K5V star with faint Br gamma emission, suggesting that it is a weak-line T Tauri object. Zeeman splitting measurements in the infrared spectrum find B ~ 2.6 +/- 1.0 kG. The flare is an extreme example of magnetic activity associated with a young stellar object. These data suggest that short observations obtained with ALMA will uncover hundreds of flaring young stellar objects in the Orion region.Comment: 29 pages, 7 figures, accepted for publication in Ap

Increasing impacts of extreme droughts on vegetation productivity under climate change

Terrestrial gross primary production (GPP) is the basis of vegetation growth and food production globally1 and plays a critical role in regulating atmospheric CO2 through its impact on ecosystem carbon balance. Even though higher CO2 concentrations in future decades can increase GPP2, low soil water availability, heat stress and disturbances associated with droughts could reduce the benefits of such CO2 fertilization. Here we analysed outputs of 13 Earth system models to show an increasingly stronger impact on GPP by extreme droughts than by mild and moderate droughts over the twenty-first century. Due to a dramatic increase in the frequency of extreme droughts, the magnitude of globally averaged reductions in GPP associated with extreme droughts was projected to be nearly tripled by the last quarter of this century (2075–2099) relative to that of the historical period (1850–1999) under both high and intermediate GHG emission scenarios. By contrast, the magnitude of GPP reductions associated with mild and moderate droughts was not projected to increase substantially. Our analysis indicates a high risk of extreme droughts to the global carbon cycle with atmospheric warming; however, this risk can be potentially mitigated by positive anomalies of GPP associated with favourable environmental conditions