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Observations of the martian atmosphere with the mars climate sounder
The Mars Climate Sounder (MCS) has obtained measurements of the Martian atmosphere for one Mars year. Onboard the Mars Reconnaissance Orbiter (MRO), MCS continues to acquire high vertical resolution profiles of temperature, dust, condensates of CO2 and H2O, and water vapor by observing the limb of the atmosphere from the surface to 80 km in the spectral intervals 0.3 – 3 ?m and 11.5 – 45 ?m [1]. This paper describes the investigation and introduces some of the observations being studied by the MCS science team. Other presentations by the team at this workshop will describe in greater detail results of ongoing research using MCS data
Main-belt comets in the Palomar Transient Factory survey – I. The search for extendedness
Cometary activity in main-belt asteroids probes the ice content of these objects and provides clues to the history of volatiles in the inner Solar system. We search the Palomar Transient Factory survey to derive upper limits on the population size of active main-belt comets (MBCs). From data collected from 2009 March through 2012 July, we extracted ∼2 million observations of ∼220 thousand known main-belt objects (40 per cent of the known population, down to ∼1-km diameter) and discovered 626 new objects in multinight linked detections. We formally quantify the ‘extendedness’ of a small-body observation, account for systematic variation in this metric (e.g. due to on-sky motion) and evaluate this method's robustness in identifying cometary activity using observations of 115 comets, including two known candidate MBCs and six newly discovered non-MBCs (two of which were originally designated as asteroids by other surveys). We demonstrate a 66 per cent detection efficiency with respect to the extendedness distribution of the 115 sampled comets, and a 100 per cent detection efficiency with respect to extendedness levels greater than or equal to those we observed in the known candidate MBCs P/2010 R2 (La Sagra) and P/2006 VW_(139). Using a log-constant prior, we infer 95 per cent confidence upper limits of 33 and 22 active MBCs (per million main-belt asteroids down to ∼1-km diameter), for detection efficiencies of 66 and 100 per cent, respectively. In a follow-up to this morphological search, we will perform a photometric (disc-integrated brightening) search for MBCs
Science with a wide-field UV transient explorer
The time-variable electromagnetic sky has been well-explored at a wide range
of wavelengths. Numerous high-energy space missions take advantage of the dark
Gamma-ray and X-ray sky and utilize very wide field detectors to provide almost
continuous monitoring of the entire celestial sphere. In visible light, new
wide-field ground-based surveys cover wide patches of sky with ever decreasing
cadence, progressing from monthly-weekly time scale surveys to sub-night
sampling. In the radio, new powerful instrumentation offers unprecedented
sensitivity over wide fields of view, with pathfinder experiments for even more
ambitious programs underway. In contrast, the ultra-violet (UV) variable sky is
relatively poorly explored, even though it offers exciting scientific
prospects. Here, we review the potential scientific impact of a wide-field UV
survey on the study of explosive and other transient events, as well as known
classes of variable objects, such as active galactic nuclei and variable stars.
We quantify our predictions using a fiducial set of observational parameters
which are similar to those envisaged for the proposed ULTRASAT mission. We show
that such a mission would be able to revolutionize our knowledge about massive
star explosions by measuring the early UV emission from hundreds of events,
revealing key physical parameters of the exploding progenitor stars. Such a
mission would also detect the UV emission from many tens of tidal-disruption
events of stars by super massive black holes at galactic nuclei and enable a
measurement of the rate of such events. The overlap of such a wide-field UV
mission with existing and planned gravitational-wave and high-energy neutrino
telescopes makes it especially timely
Asteroid rotation periods from the Palomar Transient Factory survey
The Palomar Transient Factory (PTF) is a synoptic survey designed to explore
the transient and variable sky in a wide variety of cadences. We use PTF
observations of fields that were observed multiple times (>=10) per night, for
several nights, to find asteroids, construct their lightcurves and measure
their rotation periods. Here we describe the pipeline we use to achieve these
goals and present the results from the first four (overlapping) PTF fields
analyzed as part of this program. These fields, which cover an area of 21
deg^2, were observed on four nights with a cadence of ~20 min. Our pipeline was
able to detect 624 asteroids, of which 145 (~20%) were previously unknown. We
present high quality rotation periods for 88 main-belt asteroids and possible
period or lower limit on the period for an additional 85 asteroids. For the
remaining 451 asteroids, we present lower limits on their photometric
amplitudes. Three of the asteroids have lightcurves that are characteristic of
binary asteroids. We estimate that implementing our search for all existing
high-cadence PTF data will provide rotation periods for about 10,000 asteroids
mainly in the magnitude range ~14 to ~20.Comment: 16 pages, 11 figures, 6 tables + Supplementary Material. Accepted for
publication in MNRA
Cluster Performance reconsidered: Structure, Linkages and Paths in the German Biotechnology Industry, 1996-2003
This paper addresses the evolution of biotechnology clusters in Germany between 1996 and 2003, paying particular attention to their respective composition in terms of venture capital, basic science institutions and biotechnology firms. Drawing upon the significance of co-location of "money and ideas", the literature stressing the importance of a cluster's openness and external linkages, and the path dependency debate, the paper aims to analyse how certain cluster characteristics correspond with its overall performance. After identifying different cluster types, we investigate their internal and external interconnectivity in comparative manner and draw on changes in cluster composition. Our results indicate that the structure, i.e. to which group the cluster belongs, and the openness towards external knowledge flows deliver merely unsystematic indications with regard to a cluster's overall success. Its ability to change composition towards a more balanced ratio of science and capital over time, on the other hand, turns out as a key explanatory factor. Hence, the dynamic perspective proves effective illuminating cluster growth and performance, where our explorative findings provide a promising avenue for further evolutionary research
The Earthlike Shoreline Morphology of Titan's Ontario Lacus
Ontario Lacus' shoreline features include Earth-like rivers, deltas and flooded topography. Ontario is a dynamic lake, similar in many ways to terrestrial lakes, with active shoreline processes
Detailed stratigraphy and bed thickness of the Mars north and south polar layered deposits
The Mars polar layered deposits (PLD) likely hold an extensive record of recent climate during a period of high-amplitude orbit and obliquity cycles. Previous work has detected limited evidence for orbital signatures within PLD stratigraphy, but data from the High Resolution Imaging Science Experiment (HiRISE) permit renewed analysis of PLD stratigraphy at sub-meter scale. Topography derived from HiRISE images using stereogrammetry resolves beds previously detectable only as alternating light and dark bands in visible images. We utilize these data to measure the thickness of individual beds within the PLD, corrected for non-horizontal bed orientation. Stratigraphic columns and bed thickness profiles are presented for two sites within the NPLD, and show several sets of finely bedded units 1–2 m thick; isolated marker beds 3–4 m thick; and undifferentiated sections. Bed thickness measurements for three sites within the SPLD exhibit only one bed type based on albedo and morphology, and bed thicknesses have a larger mean and variance compared to measurements for the NPLD. Power spectra of brightness and slope derived along the measured stratigraphic sections confirm the regularity of NPLD fine bed thickness, and the lack of a dominant SPLD bed thickness. The regularity of fine bed thickness of the NPLD is consistent with quasiperiodic bed formation, albeit with unknown temporal period; the SPLD thickness measurements show no such regularity
The present state of research into industrial clusters and districts. Content analysis of material published 1997-2006
[EN] The aim of this work is to help gain a better understanding of the research conducted on territorial agglomerations of firms at a multidisciplinary level. To this end, an analysis was performed of the contents of the most significant scientific literature on economics, management, planning and development, urban studies and geography published over the period 1997-2006. From the results, a database of 142 papers from 43 journals was then elaborated. An analysis of these works reveals the level of development of the main lines of research in this field and, consequently, makes it possible to detect the topics that require greater attention and that can be the object of future research for researchers and academics. The main conclusions include the growing number of studies conducted on the subject in recent years, as well as a greater predominance of empirical research over conceptual work, and the existence of a significant change in the topics or lines of research throughout the period under study. © 2012 Copyright Taylor and Francis Group, LLC.This research was financed by the Spanish Ministry of Education and Science, National R&D & Innovation Plan 2007–2010, under the project entitled “El Distrito Industrial: el impacto del Capital Social sobre la Gestio´n de la Cadena de Suministro” (The Industrial District: the impact of Social Capital on the management of the Supply Chain) (SEJ2007- 62876/ECON).Martinez-Fernandez, M.; Capó Vicedo, J.; Vallet-Bellmunt, T. (2012). The present state of research into industrial clusters and districts. Content analysis of material published 1997-2006. European Planning Studies. 20(2):281-304. doi:10.1080/09654313.2012.650906S28130420
Polar methane accumulation and rainstorms on Titan from simulations of the methane cycle
Ras Inhibition Induces Insulin Sensitivity and Glucose Uptake
BACKGROUND: Reduced glucose uptake due to insulin resistance is a pivotal mechanism in the pathogenesis of type 2 diabetes. It is also associated with increased inflammation. Ras inhibition downregulates inflammation in various experimental models. The aim of this study was to examine the effect of Ras inhibition on insulin sensitivity and glucose uptake, as well as its influence on type 2 diabetes development. METHODS AND FINDINGS: The effect of Ras inhibition on glucose uptake was examined both in vitro and in vivo. Ras was inhibited in cells transfected with a dominant-negative form of Ras or by 5-fluoro-farnesylthiosalicylic acid (F-FTS), a small-molecule Ras inhibitor. The involvement of IκB and NF-κB in Ras-inhibited glucose uptake was investigated by immunoblotting. High fat (HF)-induced diabetic mice were treated with F-FTS to test the effect of Ras inhibition on induction of hyperglycemia. Each of the Ras-inhibitory modes resulted in increased glucose uptake, whether in insulin-resistant C2C12 myotubes in vitro or in HF-induced diabetic mice in vivo. Ras inhibition also caused increased IκB expression accompanied by decreased expression of NF-κB . In fat-induced diabetic mice treated daily with F-FTS, both the incidence of hyperglycemia and the levels of serum insulin were significantly decreased. CONCLUSIONS: Inhibition of Ras apparently induces a state of heightened insulin sensitization both in vitro and in vivo. Ras inhibition should therefore be considered as an approach worth testing for the treatment of type 2 diabetes
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