Massive Quiescent Cores in Orion. -- II. Core Mass Function

We have surveyed submillimeter continuum emission from relatively quiescent regions in the Orion molecular cloud to determine how the core mass function in a high mass star forming region compares to the stellar initial mass function. Such studies are important for understanding the evolution of cores to stars, and for comparison to formation processes in high and low mass star forming regions. We used the SHARC II camera on the Caltech Submillimeter Observatory telescope to obtain 350 \micron data having angular resolution of about 9 arcsec, which corresponds to 0.02 pc at the distance of Orion. Our analysis combining dust continuum and spectral line data defines a sample of 51 Orion molecular cores with masses ranging from 0.1 \Ms to 46 \Ms and a mean mass of 9.8 \Ms, which is one order of magnitude higher than the value found in typical low mass star forming regions, such as Taurus. The majority of these cores cannot be supported by thermal pressure or turbulence, and are probably supercritical.They are thus likely precursors of protostars. The core mass function for the Orion quiescent cores can be fitted by a power law with an index equal to -0.85$\pm$0.21. This is significantly flatter than the Salpeter initial mass function and is also flatter than the core mass function found in low and intermediate star forming regions. Thus, it is likely that environmental processes play a role in shaping the stellar IMF later in the evolution of dense cores and the formation of stars in such regions.Comment: 30 pages, 10 figures, accepted by Ap

Comparative study of Cl₂, Cl₂/O₂, and Cl₂/N₂ inductively coupled plasma processes for etching of high-aspect-ratio photonic-crystal holes in InP

An extensive investigation has been performed on inductively coupled plasmaetching of InP. An important motivation for this work is the fabrication of high-aspect-ratio holes for photonic crystals. The essential chemistry is based on Cl₂ with the addition of N₂ or O₂ for sidewall passivation. The influence of different process parameters such as gas flows, temperature,pressure, ion energy, and inductively coupled plasma power on the hole geometry is presented. It is concluded that photonic crystals can be etched with Cl₂ only; however, temperature and pressure control is critical. Adding passivation gases largely broadens the window in the parameter space for hole etching. Most importantly, etching of narrow holes can be carried out at higher temperatures where the etching is mass limited and spontaneous etching of InP by Cl₂ occurs.Part of this research is supported by NanoNed, a technology program of the Dutch Ministry of Economic Affairs

Motor ability in children treated for idiopathic clubfoot. A controlled pilot study

<p>Abstract</p> <p>Background</p> <p>To study motor ability at seven years of age in children treated for idiopathic clubfoot and its relation to clubfoot laterality, foot status and the amount of surgery performed.</p> <p>Methods</p> <p>Twenty children (mean age 7.5 years, SD 3.2 months) from a consecutive birth cohort from our hospital catchments area (300.000 inhabitants from southern Sweden) were assessed with the Movement Assessment Battery for Children (MABC) and the Clubfoot Assessment Protocol (CAP).</p> <p>Results</p> <p>Compared to typically developing children an increased prevalence of motor impairment was found regarding both the total score for MABC (p < 0.05) and the subtest ABC-Ball skills (p < 0.05). No relationship was found between the child's actual foot status, laterality or the extent of foot surgery with the motor ability as measured with MABC. Only the CAP item "one-leg stand" correlated significantly with the MABC (rs = -0.53, p = 0.02).</p> <p>Conclusions</p> <p>Children with idiopathic clubfoot appear to have an increased risk of motor activity limitations and it is possible that other factors, independent of the clinical status, might be involved. The ability to keep balance on one leg may be a sufficient tool for determining which children in the orthopedic setting should be more thoroughly evaluated regarding their neuromotor functioning.</p

The Anomalous Infrared Emission of Abell 58

We present a new model to explain the excess in mid and near infrared emission of the central, hydrogen poor dust knot in the planetary nebula (PN) Abell 58. Current models disagree with ISO measurement because they apply an average grain size and equilibrium conditions only. We investigate grain size distributions and temperature fluctuations affecting infrared emission using a new radiative transfer code and discuss in detail the conditions requiring an extension of the classical description. The peculiar infrared emission of V605 Aql, the central dust knot in Abell 58, has been modeled with our code. V605 Aql is of special interest as it is one of only three stars ever observed to move from the evolutionary track of a central PN star back to the post-AGB state.Comment: 17 pages, 4 figures; accepted and to be published in Ap

Benchmarking Crimes: An Emerging Threat in Systems Security

Properly benchmarking a system is a difficult and intricate task. Unfortunately, even a seemingly innocuous benchmarking mistake can compromise the guarantees provided by a given systems security defense and also put its reproducibility and comparability at risk. This threat is particularly insidious as it is generally not a result of malice and can easily go undetected by both authors and reviewers. Moreover, as modern defenses often trade off security for performance in an attempt to find an ideal design point in the performance-security space, the damage caused by benchmarking mistakes is increasingly worrisome. To analyze the magnitude of the phenomenon, we identify a set of 22 "benchmarking crimes" that threaten the validity of systems security evaluations and perform a survey of 50 defense papers published in top venues. To ensure the validity of our results, we perform the complete survey twice, with two independent readers. We find only a very small number of disagreements between readers, showing that our assessment of benchmarking crimes is highly reproducible. We show that benchmarking crimes are widespread even in papers published at tier-1 venues. We find that tier-1 papers commit an average of five benchmarking crimes and we find only a single paper in our sample that committed no benchmarking crimes. Moreover, we find that the scale of the problem is constant over time, suggesting that the community is not yet addressing it despite the problem being now more relevant than ever. This threatens the scientific process, which relies on reproducibility and comparability to ensure that published research advances the state of the art. We hope to raise awareness of these issues and provide recommendations to improve benchmarking quality and safeguard the scientific process in our community. Computer Systems, Imagery and Medi

Constraints on new interactions from neutron scattering experiments

Constraints for the constants of hypothetical Yukawa-type corrections to the Newtonian gravitational potential are obtained from analysis of neutron scattering experiments. Restrictions are obtained for the interaction range between 10^{-12} and 10^{-7} cm, where Casimir force experiments and atomic force microscopy are not sensitive. Experimental limits are obtained also for non-electromagnetic inverse power law neutron-nucleus potential. Some possibilities are discussed to strengthen these constraints.Comment: 18 pages, 3 figure

Validity and responsiveness of the Clubfoot Assessment Protocol (CAP). A methodological study

BACKGROUND: The Clubfoot Assessment Protocol (CAP) is a multi dimensional instrument designed for longitudinal follow up of the clubfoot deformity during growth. Item reliability has shown to be sufficient. In this article the CAP's validity and responsiveness is studied using the Dimeglio classification scoring as a gold standard. METHODS: Thirty-two children with 45 congenital clubfeet were assessed prospectively and consecutively at ages of new-born, one, two, four months and two years of age. For convergent/divergent construct validity the Spearman's correlation coefficients were calculated. Discriminate validity was evaluated by studying the scores in bilateral clubfeet. The floor-ceiling effects at baseline (untreated clubfeet) and at two years of age (treated clubfeet) were evaluated. Responsiveness was evaluated by using effect sizes (ES) and by calculating if significant changes (Wilcoxons signed test) had occurred between the different measurement occasions. RESULTS: High to moderate significant correlation were found between CAP mobility I and morphology and the Dimeglio scores (r(s )= 0.77 and 0.44 respectively). Low correlation was found between CAP muscle function, mobility II and motion quality and the Dimeglio scoring system (r(s )= 0.20, 0.09 and 0.06 respectively). Of 13 children with bilateral clubfeet, 11 showed different CAP mobility I scores between right and left foot at baseline (untreated) compared with 5 with the Dimeglio score. At the other assessment occasions the CAP mobility I continued to show higher discrimination ability than the Dimeglio. No floor effects and low ceiling effects were found in the untreated clubfeet for both instruments. High ceiling effects were found in the CAP for the treated children and low for the Dimeglio. Responsiveness was good. ES from untreated to treated ranged from 0.80 to 4.35 for the CAP subgroups and was 4.68 for the Dimeglio. The first four treatment months, the CAP mobility I had generally higher ES compared with the Dimeglio. CONCLUSION: The Clubfoot Assessment Protocol shows in this study good validity and responsiveness. The CAP is more responsive when severity ranges between mild – moderate to severe, while the Dimeglio focuses more on the extremes. The ability to discriminate between different mobility status of the right and left foot in bilaterally affected children in this population was higher compared with the Dimeglio score implicating a better sensitivity for the CAP

Infrared Emission from Interstellar Dust. I. Stochastic Heating of Small Grains

We present a method for calculating the infrared emission from a population of dust grains heated by starlight, including very small grains for which stochastic heating by starlight photons results in high temperature transients. Because state-to-state transition rates are generally unavailable for complex molecules, we consider model PAH, graphitic, and silicate grains with realistic vibrational mode spectra and realistic radiative properties. The vibrational density of states is used in a statistical-mechanical description of the emission process. Unlike previous treatments, our approach fully incorporates multiphoton heating effects, important for large grains or strong radiation fields. We discuss how the "temperature" of the grain is related to its vibrational energy. By comparing with an "exact" statistical calculation of the emission process, we determine the conditions under which the "thermal" and the "continuous cooling" approximations can be used to calculate the emission spectrum. We present results for the infrared emission spectra of PAH grains of various sizes heated by starlight. We show how the relative strengths of the 6.2, 7.7, and 11.3um features depend on grain size, starlight spectrum and intensity, and grain charging conditions. We show results for grains in the "cold neutral medium", "warm ionized medium", and representative conditions in photodissociation regions. Our model results are compared to observed ratios of emission features for reflection nebulae and photodissociation regions, the Milky Way, normal spiral galaxies, and starburst galaxies.Comment: Submitted to ApJ. 42 pages, 18 figures, Late

The clubfoot assessment protocol (CAP); description and reliability of a structured multi-level instrument for follow-up

BACKGROUND: In most clubfoot studies, the outcome instruments used are designed to evaluate classification or long-term cross-sectional results. Variables deal mainly with factors on body function/structure level. Wide scorings intervals and total sum scores increase the risk that important changes and information are not detected. Studies of the reliability, validity and responsiveness of these instruments are sparse. The lack of an instrument for longitudinal follow-up led the investigators to develop the Clubfoot Assessment Protocol (CAP). The aim of this article is to introduce and describe the CAP and evaluate the items inter- and intra reliability in relation to patient age. METHODS: The CAP was created from 22 items divided between body function/structure (three subgroups) and activity (one subgroup) levels according to the International Classification of Function, Disability and Health (ICF). The focus is on item and subgroup development. Two experienced examiners assessed 69 clubfeet in 48 children who had a median age of 2.1 years (range, 0 to 6.7 years). Both treated and untreated feet with different grades of severity were included. Three age groups were constructed for studying the influence of age on reliability. The intra- rater study included 32 feet in 20 children who had a median age of 2.5 years (range, 4 months to 6.8 years). The Unweighted Kappa statistics, percentage observer agreement, and amount of categories defined how reliability was to be interpreted. RESULTS: The inter-rater reliability was assessed as moderate to good for all but one item. Eighteen items had kappa values > 0.40. Three items varied from 0.35 to 0.38. The mean percentage observed agreement was 82% (range, 62 to 95%). Different age groups showed sufficient agreement. Intra- rater; all items had kappa values > 0.40 [range, 0.54 to 1.00] and a mean percentage agreement of 89.5%. Categories varied from 3 to 5. CONCLUSION: The CAP contains more detailed information than previous protocols. It is a multi-dimensional observer administered standardized measurement instrument with the focus on item and subgroup level. It can be used with sufficient reliability, independent of age, during the first seven years of childhood by examiners with good clinical experience. A few items showed low reliability, partly dependent on the child's age and /or varying professional backgrounds between the examiners. These items should be interpreted with caution, until further studies have confirmed the validity and sensitivity of the instrument

Prophylactic treatment of migraine; the patient's view, a qualitative study

Contains fulltext : 109202.pdf (publisher's version ) (Open Access)BACKGROUND: Prophylactic treatment is an important but under-utilised option for the management of migraine. Patients and physicians appear to have reservations about initiating this treatment option. This paper explores the opinions, motives and expectations of patients regarding prophylactic migraine therapy. METHODS: A qualitative focus group study in general practice in the Netherlands with twenty patients recruited from urban and rural general practices. Three focus group meetings were held with 6-7 migraine patients per group (2 female and 1 male group). All participants were migraine patients according to the IHS (International Headache Society); 9 had experience with prophylactic medication. The focus group meetings were analysed using a general thematic analysis. RESULTS: For patients several distinguished factors count when making a decision on prophylactic treatment. The decision of a patient on prophylactic medication is depending on experience and perspectives, grouped into five categories, namely the context of being active or passive in taking the initiative to start prophylaxis; assessing the advantages and disadvantages of prophylaxis; satisfaction with current migraine treatment; the relationship with the physician and the feeling to be heard; and previous steps taken to prevent migraine. CONCLUSION: In addition to the functional impact of migraine, the decision to start prophylaxis is based on a complex of considerations from the patient's perspective (e.g. perceived burden of migraine, expected benefits or disadvantages, interaction with relatives, colleagues and physician). Therefore, when advising migraine patients about prophylaxis, their opinions should be taken into account. Patients need to be open to advice and information and intervention have to be offered at an appropriate moment in the course of migraine