The Mass Function of Newly Formed Stars (Review)

The topic of the stellar "original mass function" has a nearly 50 year history,dating to the publication in 1955 of Salpeter's seminal paper. In this review I discuss the many more recent results that have emerged on the initial mass function (IMF), as it is now called, from studies over the last decade of resolved populations in star forming regions and young open clusters.Comment: 9 pages, 1 figure; to appear in "The Dense Instellar Medium in Galaxies -- 4'th Cologne-Bonn-Zermatt-Symposium" editted by S. Pfalzner, C. Kramer, C. Straubmeier and A. Heithausen, Springer-Verlag (2004

Cause and Effectors: whole genome comparisons reveal shared but rapidly evolving effector sets among host-specific plant-castrating fungi

International audienceWord Count: 240 16 17 Text Word Count: 6,466 1

Advancing in the estimation of effective recharge and its propagation in karst aquifers by combining soil moisture observations and the natural responses of springs. An example from Southern Spain.

Improving our comprehension of infiltration processes in karst systems is crucial for a better adaptation to the global change regarding water resources availability and management. In this work, the effective recharge under different meteorological conditions and its transfer along the vertically distributed compartments of a geologically complex karst aquifer in southern Spain have been evaluated. Continuous records of soil moisture and temperature values (at 5 and 10 cm depth and the soil-rock transition -average depth of 28 cm-) have been combined with hourly hydrodynamic and hydrothermal responses recorded at two springs with a marked influence of the unsaturated zone (UZ) and the saturated zone (SZ), respectively. Most rainfalls generate soil moisture signal in the shallowest probes. However, a mean increase of soil water content of 10.5% in summer (from background values of 2.5%) and 6.1% in autumn-winter (from 9.6%) at the soil-rock interface were needed to produce hydrodynamic responses in the system: first in the spring related to the UZ, with a time delay of 4-9 hours after moisture peaks, and then (14-18 hours) in the spring draining the SZ, but only during autumn-winter recharge events. In addition, recharge caused decreases (up to 0.9°C) in the temperature of the water drained by the first spring, while lagged rises (up to 0.6°C) occurred in the second outlet. Transmission of the input signal would be favoured by stronger karstification, but the presence of inter-bedded detrital formations in the lithological sequence of the aquifer (partially confined in the SE border) filter and buffer groundwater flows before being drained by the spring related to the SZ. These findings will help to assess thresholds for effective infiltration and to predict groundwater recharge in karst aquifers under different climate change scenarios.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

On the universal outcome of star-formation: Is there a link between stars and brown-dwarfs?

(abridged) The recent evidence obtained by Briceno et al. that star-formation in Taurus-Auriga (TA) may be producing significantly fewer brown dwarfs (BDs) per star than the ONC is investigated by setting up a realistic model stellar plus BD population and explicitly taking into account a high binary proportion and dynamical evolution in the TA groups and the ONC. The Briceno result is reproduced almost exactly despite an identical IMF in both systems because many BD-BD and star-BD binaries are disrupted in the ONC thus freeing BDs, while the TA groups remain unevolved dynamically. However, the resulting populations do not have the correct star-star, star-BD and expecially BD-BD binary properties, even if a variable BD IMF is allowed for. The conclusion is therefore that BDs need to be added as a separate population which has its own binary properties. Such an extra population can have various origins which are briefly discussed in this contribution but more fully in an associated paper.Comment: MNRAS, accepted, 23 pages, 14 figures, LaTeX, two references adde

Are There Age Spreads in Star Forming Regions?

A luminosity spread at a given effective temperature is ubiquitously seen in the Hertzsprung-Russell (HR) diagrams of young star forming regions and often interpreted in terms of a prolonged period (>=10 Myr) of star formation. I review the evidence that the observed luminosity spreads are genuine and not caused by astrophysical sources of scatter. I then address whether the luminosity spreads necessarily imply large age spreads, by comparing HR diagram ages with ages from independent clocks such as stellar rotation rate, the presence of circumstellar material and lithium depletion. I argue that whilst there probably is a true luminosity dispersion, there is little evidence to support age spreads larger than a few Myr. This paradox could be resolved by brief periods of rapid accretion during the class I pre main-sequence phase.Comment: To appear in the proceedings of JENAM10: Star Clusters in the Era of Large Surveys, 8 page

Quantum-Well Infrared Photodetector (QWIP) Focal Plane Assembly

A paper describes the Thermal Infrared Sensor (TIRS), a QWIP-based instrument intended to supplement the Operational Land Imager (OLI) for the Landsat Data Continuity Mission (LDCM). The TIRS instrument is a far-infrared imager operating in the pushbroom mode with two IR channels: 10.8 and 12 microns. The focal plane will contain three 640x512 QWIP arrays mounted on a silicon substrate. The silicon substrate is a custom-fabricated carrier board with a single layer of aluminum interconnects. The general fabrication process starts with a 4-in. (approx.10-cm) diameter silicon wafer. The wafer is oxidized, a single substrate contact is etched, and aluminum is deposited, patterned, and alloyed. This technology development is aimed at incorporating three large-format infrared detecting arrays based on GaAs QWIP technology onto a common focal plane with precision alignment of all three arrays. This focal plane must survive the rigors of flight qualification and operate at a temperature of 43 K (-230 C) for five years while orbiting the Earth. The challenges presented include ensuring thermal compatibility among all the components, designing and building a compact, somewhat modular system and ensuring alignment to very tight levels. The multi-array focal plane integrated onto a single silicon substrate is a new application of both QWIP array development and silicon wafer scale integration. The Invar-based assembly has been tested to ensure thermal reliability

Swift/BAT detection of hard X-rays from Tycho's Supernova Remnant: Evidence for Titanium-44

We report Swift/BAT survey observations of the Tycho's supernova remnant, performed over a period of 104 months since the mission's launch. The remnant is detected with high significance (>10 sigma) below 50 keV. We detect significant hard X-ray emission in the 60-85 keV band, above the continuum level predicted by a simple synchrotron model. The location of the observed excess is consistent with line emission from radioactive Titanium-44, so far reported only for Type II supernova explosions. We discuss the implications of these results in the context of the galactic supernova rate, and nucleosynthesis in Type Ia supernova.Comment: 5 pages, 4 figures, accepted for publication in ApJ

Practitioner Review: Assessment and treatment of body dysmorphic disorder in young people

Body dysmorphic disorder (BDD) is a relatively common and highly impairing mental disorder that is strikingly underdiagnosed and undertreated in Child and Adolescent Mental Health Services (CAMHS). The only clinical guidelines for the management of BDD in youth were published nearly 20 years ago, when empirical knowledge was sparse. Fortunately, there has been a surge in research into BDD over the last 10 years, shedding important insights into the phenomenology, epidemiology, assessment and treatment of the disorder in young people. This review aimed to provide an overview of recent research developments of relevance to clinicians and healthcare policymakers. We summarise key findings regarding the epidemiology of BDD in youth, which indicate that the disorder usually develops during teenage years and affects approximately 2% of adolescents at any one point in time. We provide an overview of aetiological research, highlighting that BDD arises from an interplay between genetic and environmental influences. We then focus on screening and assessment strategies, arguing that these are crucial to promote detection and diagnosis of this under-recognised condition. Additionally, we summarise the recommended treatment approaches for BDD in youth, namely cognitive behaviour therapy with or without selective serotonin reuptake inhibitors. The review concludes by highlighting key knowledge gaps and priorities for future research including, but not limited to, better understanding aetiological factors, long-term consequences and treatment