University of Colorado Boulder

About: University of Colorado Boulder is a education organization based out in Boulder, Colorado, United States. It is known for research contribution in the topics: Population & Galaxy. The organization has 48794 authors who have published 115151 publications receiving 5387328 citations. The organization is also known as: CU Boulder & UCB.

Spectroscopy Made Easy: A New Tool for Fitting Observations with Synthetic Spectra

Abstract: We describe a new software package that may be used to determine stellar and atomic parameters by matching observed spectra with synthetic spectra generated from parameterized atmospheres. A nonlinear least squares algorithm is used to solve for any subset of allowed parameters, which include atomic data (loggf and van der Waals damping constants), model atmosphere specications (Te ,l og g), elemental abundances, and radial, turbulent, and rotational velocities. LTE synthesis software handles discontiguous spectral intervals and complex atomic blends. As a demonstration, we t 26 Fe I lines in the NSO Solar Atlas (Kurucz et al. 1984), determining various solar and atomic parameters.

Medial prefrontal cortex determines how stressor controllability affects behavior and dorsal raphe nucleus.

Abstract: The degree of behavioral control that an organism has over a stressor is a potent modulator of the stressor's impact; uncontrollable stressors produce numerous outcomes that do not occur if the stressor is controllable. Research on controllability has focused on brainstem nuclei such as the dorsal raphe nucleus (DRN). Here we find that the infralimbic and prelimbic regions of the ventral medial prefrontal cortex (mPFCv) in rats detect whether a stressor is under the organism's control. When a stressor is controllable, stress-induced activation of the DRN is inhibited by the mPFCv, and the behavioral sequelae of uncontrollable stress are blocked. This suggests a new function for the mPFCv and implies that the presence of control inhibits stress-induced neural activity in brainstem nuclei, in contrast to the prevalent view that such activity is induced by a lack of control.

Recent contributions of glaciers and ice caps to sea level rise

Abstract: Satellite measurements of Earth’s gravity field show that the mass loss of glaciers and ice caps contributed to sea level rise by approximately 0.4 millimetres per year between 2003 and 2010. The extent to which mass loss from ice-covered land areas contributes to sea-level rise is not known accurately, in part because previous global estimates use different techniques for glaciers, ice caps and ice sheets. The Gravity Recovery and Climate Experiment (GRACE) satellite has provided monthly measurements of the global gravity field since 2002. Using GRACE data, Jacob et al. assess regional mass loss between 2003 and 2010, and conclude that mass loss from ice-covered land areas contributed almost 1.5 mm per year to the sea-level rise. Estimated mass loss from the high mountains of Asia was negligible, in contrast to some other reports. Glaciers and ice caps (GICs) are important contributors to present-day global mean sea level rise1,2,3,4. Most previous global mass balance estimates for GICs rely on extrapolation of sparse mass balance measurements1,2,4 representing only a small fraction of the GIC area, leaving their overall contribution to sea level rise unclear. Here we show that GICs, excluding the Greenland and Antarctic peripheral GICs, lost mass at a rate of 148 ± 30 Gt yr−1 from January 2003 to December 2010, contributing 0.41 ± 0.08 mm yr−1 to sea level rise. Our results are based on a global, simultaneous inversion of monthly GRACE-derived satellite gravity fields, from which we calculate the mass change over all ice-covered regions greater in area than 100 km2. The GIC rate for 2003–2010 is about 30 per cent smaller than the previous mass balance estimate that most closely matches our study period2. The high mountains of Asia, in particular, show a mass loss of only 4 ± 20 Gt yr−1 for 2003–2010, compared with 47–55 Gt yr−1 in previously published estimates2,5. For completeness, we also estimate that the Greenland and Antarctic ice sheets, including their peripheral GICs, contributed 1.06 ± 0.19 mm yr−1 to sea level rise over the same time period. The total contribution to sea level rise from all ice-covered regions is thus 1.48 ± 0.26 mm −1, which agrees well with independent estimates of sea level rise originating from land ice loss and other terrestrial sources6.