A Contracting, Turbulent, Starless Core in the Serpens Cluster

We present combined single-dish and interferometric CS(2--1) and N2H+(1--0) observations of a compact core in the NW region of the Serpens molecular cloud. The core is starless according to observations from optical to millimeter wavelengths and its lines have turbulent widths and ``infall asymmetry''. Line profile modeling indicates supersonic inward motions v_in>0.34 km/s over an extended region L>12000AU. The high infall speed and large extent exceeds the predictions of most thermal ambipolar diffusion models and points to a more dynamical process for core formation. A short (dynamic) timescale, ~1e5 yr=L/v_in, is also suggested by the low N2H+ abundance ~1e-10.Comment: 11 pages including 2 figures. Accepted for publication in the Astrophysical Journal Letter

1,10-Phenanthrolin-1-ium 2-carb­oxy-4,5-dichloro­benzoate

In the structure of the 1:1 proton-transfer compound of 1,10-phenanthroline with 4,5-dichloro­phthalic acid, C12H9N2 +·C8H3Cl2O4 −, determined at 130 K, the 1,10-phenanthrolinium cation and the hydrogen 4,5-dichloro­phthalate anion associate through a single N—H⋯Ocarbox­yl hydrogen bond giving discrete units which have no extension except through a number of weak cation C—H⋯Oanion associations and weak cation–anion aromatic ring π–π inter­actions [minimum centroid–centroid separation = 3.6815 (12) Å]. The anions are essentially planar "[maximum deviation 0.214 (1) Å (a carboxyl O)] with the syn-related H atom of the carboxyl group, forming a short intra­molecular O—H⋯Ocarbox­yl hydrogen bond

2-Carboxy­quinolinium–2,4,6-trinitro­benzene­sulfonate–quinolinium-2-carboxyl­ate (1/1/1)

The structure of the title adduct compound, C10H8NO2 +·C6H2N3O9S−·C10H7NO2, from the reaction of 2,4,6-trinitro­benzene­sulfonic acid (picrylsulfonic acid) with quinoline-2-carboxylic acid (quinaldic acid) in 2-propanol–water, has been determined at 130 (2) K. The cation and the adduct species form a twisted cyclic hydrogen-bonded R 2 2(10) pseudo-dimer which is extended into a one-dimensional chain structure through short head-to-tail carboxylic acid O—H⋯Ocarbox­yl associations [O⋯O = 2.4711 (19) Å]. The picrylsulfonate anions are attached peripherally by single N—H⋯Osulfonate hydrogen bonds [N⋯O = 2.8643 (19) Å]

4-Chloro­anilinium 2-carb­oxy-4,5-dichloro­benzoate

The structure of the 1:1 proton-transfer compound of 4-chloro­aniline with 4,5-dichloro­phthalic acid (DCPA), viz. C6H7ClN+·C8H3Cl2O4 −, has been determined at 130 K. The non-planar hydrogen phthalate anions and the 4-chloro­anilinium cations form two-dimensional O—H⋯O and N—H⋯O hydrogen-bonded substructures which have no peripheral extension. Between the sheets there are weak π–π associations between alternating cation–anion aromatic ring systems [shortest centroid–centroid separation = 3.735 (4) Å]

Diagnostic accuracy of digital photography and image analysis for the measurement of foot conformation in the horse

Experimental studies have shown that foot conformation influences the forces experienced by the distal limb (Riemersma et al. 1996; Wilson et al. 1998; Willemen et al. 1999; Eliashar et al. 2004). Although some clinical studies have highlighted the importance of foot conformation as a risk factor for musculoskeletal injury (Kane et al. 1998; Anderson et al. 2004), this has not been a universal finding (Weller et al. 2006c). Clearly more information from large, well designed, prospective studies is needed to elucidate further the relationship between foot conformation and injury. This information would help to guide veterinary surgeons and farriers in the trimming and shoeing of horses’ feet, a practice carried out regularly (usually every 4-8 weeks) during the animal’s life. In order to further investigate this relationship, a tool capable of accurately, precisely and practicably collecting suitable objective data, ideally at relatively low cost, is necessary. The variability introduced by image acquisition and subsequent analysis using digital image processing software of digital photographs of the foot has not been quantified. Similarly the level of agreement between objective measurements of foot conformation made from digital photography and digital radiography is unknown. The objectives of this project were to assess the precision, accuracy and practicability of the entire process of obtaining measurements of horses’ feet using digital photography and the digital image processing software (Metron-PX™). For the precision study (prospective in vivo randomised clinical measurement study) lateral digital photographs of shod Thoroughbred racehorses were obtained twice by two veterinary surgeons working independently (Image Acquisition - IAc). Each photograph was independently analysed by the two veterinary surgeons masked to the origin of the images on two occasions using Metron-PX™ (Image Analysis - IAn). Measurements generated by the software were compared within and between operators of the software for self and non-self acquired photographs. Intra- and inter-operator agreement indices (AIs) and 95% limits of agreement (LOA) were calculated for each measurement for the IAn process alone and for the combined IAc + IAn processes for self and non-self acquired images respectively. For the accuracy study (method comparison study) measurements obtained from lateral digital photographs (index test), as in the precision study, were compared with those obtained from lateromedial radiographs (reference standard). Agreement indices (AIs) and 95% limits of agreement were calculated for each measurement. The results of the precision study identified excellent mean intra- and inter-operator AIs for the IAn process alone ( 0.90 for all measurements). The mean intra- and inter-operator AIs for the combined IAc + IAn processes were 0.89 for all measurements with similar AIs obtained regardless of whether or not the individual whom acquired the images also analysed them. The 95% limits of agreement for hoof angle, heel height/ toe height% and coronary band angle for all comparisons were all within target values. The results of the accuracy study identified mean AIs that were 0.89 for all measurements. The 95% limits of agreement for heel height/ toe height% and coronary band angle were within target values. Overall, there was excellent precision both within and between operators of the measurement process for both the image analysis process alone and the combined image acquisition and analysis processes. When the described technique is used results are comparable irrespective of whether the person whom acquired the images also analyses them. Excellent accuracy was also identified between the photographic and radiographic measurements, especially for heel height/ toe height% and coronary band angle, suggesting that these two methods may be used interchangeably for these measurements of foot conformation in the horse. The clinical relevance of these findings is that the processes described for obtaining objective measurements of foot conformation from digital photographs and digital image processing software Metron-PX™ is practicable and produces highly precise measurements regardless of whether the same operator performs both image acquisition and analysis. Photographic measurements of heel height/ toe height% and coronary band angle closely approximate radiographic measurements such that the two techniques may be used interchangeably. Thus, digital photography and image analysis have applications in the field of clinical telemedicine and would be particularly useful to a large prospective multi-centre study investigating the relationship between foot conformation and musculoskeletal injury

Surface chemistry of hydrazine on Pt(111)

Elever vid vuxenutbildningen har rätt till stöd i form av extra anpassningar. Däremot finns det inga krav på dokumentation i form åtgärdsprogram. Hur arbetar man inom vuxenutbildningen med de elever som är i behov av utökat stöd i matematik? Avsikten med studien är att undersöka hur man kan fånga upp och dokumentera arbetet med elever i behov av utökat stöd i matematik vid vuxenutbildningen.   För att uppnå studiens syfte valdes aktionsforskning som metod och teori. Intervjuer, diskussioner och reflektion tillsammans med de undervisande lärarna har legat till grund för den cykliska processen och analysen enligt Kurt Lewins teori. I aktionerna utarbetades en strategisk handlingsplan, vilken slutligen bestod av elevenkäter, intervjuguide samt användandet av matematisk kartläggning. Utifrån det gjordes en strukturerad dokumentation av arbetet med extra anpassningar. Det utarbetade arbetssättet möjliggjorde för lärare, men även för rektor, att få en överblick av det arbete som görs och det gav förutsättningar att kunna följa upp och utvärdera arbetet med extra anpassningar. Därav kan den strategiska handlingsplanen ses som en viktig del i det systematiska kvalitetsarbetet vid vuxenutbildningen

Reconstructing the massive black hole cosmic history through gravitational waves

The massive black holes we observe in galaxies today are the natural end-product of a complex evolutionary path, in which black holes seeded in proto-galaxies at high redshift grow through cosmic history via a sequence of mergers and accretion episodes. Electromagnetic observations probe a small subset of the population of massive black holes (namely, those that are active or those that are very close to us), but planned space-based gravitational-wave observatories such as the Laser Interferometer Space Antenna (LISA) can measure the parameters of ``electromagnetically invisible'' massive black holes out to high redshift. In this paper we introduce a Bayesian framework to analyze the information that can be gathered from a set of such measurements. Our goal is to connect a set of massive black hole binary merger observations to the underlying model of massive black hole formation. In other words, given a set of observed massive black hole coalescences, we assess what information can be extracted about the underlying massive black hole population model. For concreteness we consider ten specific models of massive black hole formation, chosen to probe four important (and largely unconstrained) aspects of the input physics used in structure formation simulations: seed formation, metallicity ``feedback'', accretion efficiency and accretion geometry. For the first time we allow for the possibility of ``model mixing'', by drawing the observed population from some combination of the ``pure'' models that have been simulated. A Bayesian analysis allows us to recover a posterior probability distribution for the ``mixing parameters'' that characterize the fractions of each model represented in the observed distribution. Our work shows that LISA has enormous potential to probe the underlying physics of structure formation.Comment: 24 pages, 16 figures, submitted to Phys. Rev.

FoxP2 isoforms delineate spatiotemporal transcriptional networks for vocal learning in the zebra finch.

Human speech is one of the few examples of vocal learning among mammals yet ~half of avian species exhibit this ability. Its neurogenetic basis is largely unknown beyond a shared requirement for FoxP2 in both humans and zebra finches. We manipulated FoxP2 isoforms in Area X, a song-specific region of the avian striatopallidum analogous to human anterior striatum, during a critical period for song development. We delineate, for the first time, unique contributions of each isoform to vocal learning. Weighted gene coexpression network analysis of RNA-seq data revealed gene modules correlated to singing, learning, or vocal variability. Coexpression related to singing was found in juvenile and adult Area X whereas coexpression correlated to learning was unique to juveniles. The confluence of learning and singing coexpression in juvenile Area X may underscore molecular processes that drive vocal learning in young zebra finches and, by analogy, humans

Control theory for principled heap sizing

We propose a new, principled approach to adaptive heap sizing based on control theory. We review current state-of-the-art heap sizing mechanisms, as deployed in Jikes RVM and HotSpot. We then formulate heap sizing as a control problem, apply and tune a standard controller algorithm, and evaluate its performance on a set of well-known benchmarks. We find our controller adapts the heap size more responsively than existing mechanisms. This responsiveness allows tighter virtual machine memory footprints while preserving target application throughput, which is ideal for both embedded and utility computing domains. In short, we argue that formal, systematic approaches to memory management should be replacing ad-hoc heuristics as the discipline matures. Control-theoretic heap sizing is one such systematic approach