Search

We present the Living Swift- XRT Point Source (LSXPS) catalogue and real-time transient detector. This system allows us for the first time to carry out low-latency searches for new transient X-ray events fainter than those available to the current generation of wide-field imagers, and report their detection in near real time. Previously, such events could only be found in delayed searches, e.g. of archival data; our low-latency analysis now enables rapid and ongoing follow-up of these events, enabling the probing of time-scales previously inaccessible. The LSXPS is, uniquely among X-ray catalogues, updated in near real time, making this the first up-to-date record of the point sources detected by a sensitive X-ray telescope: the Swift X-ray Telescope. The associated upper limit calculator likewise makes use of all available data allowing contemporary upper limits to be rapidly produced on demand. These facilities, which enable the low-latency transient system, are also fully available to the community, providing a powerful resource for time-domain and multimessenger astrophysics. [ABSTRACT FROM AUTHOR]

This Account summarizes our recent work on rhodium-catalyzed allylic alkylation reactions with nitrile-stabilized carbanions. Despite the challenges associated with employing nitrile-stabilized nucleophiles in transition-metal-catalyzed reactions, we have developed enantiospecific and enantioselective allylic alkylation reactions. Notably, these novel reactions permit expedient and selective access to an array of acyclic ternary and quaternary stereogenic centers present in important biologically active and functional molecules. 1 Introduction 2 Enantiospecific Allylic Alkylation Reactions with Nitrile-Stabilized Anions 3 Enantioselective Allylic Alkylation Reactions with Nitrile-Stabilized Anions 4 Conclusion [ABSTRACT FROM AUTHOR]

The Neil Gehrels Swift Observatory followed up 18 gravitational wave (GW) triggers from the LIGO/Virgo collaboration during the O3 observing run in 2019/2020, performing approximately 6500 pointings in total. Of these events, four were finally classified (if real) as binary black hole (BH) triggers, six as binary neutron star (NS) events, two each of NSBH and Mass Gap triggers, one an unmodelled (Burst) trigger, and the remaining three were subsequently retracted. Thus far, four of these O3 triggers have been formally confirmed as real gravitational wave events. While no likely electromagnetic counterparts to any of these GW events have been identified in the X-ray data (to an average upper limit of 3.60 × 10−12 erg cm−2 s−1 over 0.3–10 keV), or at other wavelengths, we present a summary of all the Swift -XRT observations performed during O3, together with typical upper limits for each trigger observed. The majority of X-ray sources detected during O3 were previously uncatalogued; while some of these will be new (transient) sources, others are simply too faint to have been detected by earlier survey missions such as ROSAT. The all-sky survey currently being performed by eROSITA will be a very useful comparison for future observing runs, reducing the number of apparent candidate X-ray counterparts by up to 95 per cent. [ABSTRACT FROM AUTHOR]

To demarcate the limits of experimental knowledge, we probe the limits of what might be called an experiment. By appeal to examples of scientific practice from astrophysics and analogue gravity, we demonstrate that the reliability of knowledge regarding certain phenomena gained from an experiment is not circumscribed by the manipulability or accessibility of the target phenomena. Rather, the limits of experimental knowledge are set by the extent to which strategies for what we call 'inductive triangulation' are available: that is, the validation of the mode of inductive reasoning involved in the source-target inference via appeal to one or more distinct and independent modes of inductive reasoning. When such strategies are able to partially mitigate reasonable doubt, we can take a theory regarding the phenomena to be well supported by experiment. When such strategies are able to fully mitigate reasonable doubt, we can take a theory regarding the phenomena to be established by experiment. There are good reasons to expect the next generation of analogue experiments to provide genuine knowledge of unmanipulable and inaccessible phenomena such that the relevant theories can be understood as well supported. [ABSTRACT FROM AUTHOR]

Background: Worldwide, snakebite envenomations total ~2.7 million reported cases annually with ~100,000 fatalities. Since 2009, snakebite envenomation has intermittently been classified as a very important ‘neglected tropical disease’ by the World Health Organisation. Despite this emerging awareness, limited efforts have been geared towards addressing the serious public health implications of snakebites, particularly in sub-Saharan Africa, where baseline epidemiological and ecological data remain incomplete. Due to poverty as well as limited infrastructure and public health facilities, people in rural Africa, including Ghana, often have no other choice than to seek treatment from traditional medical practitioners (TMPs). The African ‘snakebite crisis’ is highlighted here using regionally representative complementary data from a community-based epidemiological and ecological study in the savanna zone of northern Ghana. Methodology and findings: Our baseline study involved two data collection methods in the Savelugu-Nanton District (in 2019 the district was separated into Savelugu and Nanton districts) in northern Ghana, comprising a cross-sectional study of 1,000 residents and 24 TMPs between December 2008 and May 2009. Semi-structured interviews, as well as collection of retrospective snakebite and concurrent rainfall records from the Savelugu-Nanton District Hospital and Ghana Meteorological Authority respectively over 10-years (1999–2008) were used in the study. Variables tested included demography, human activity patterns, seasonality, snake ecology and clinical reports. Complementary data showed higher snakebite prevalence during the rainy season, and a hump-shaped correlation between rainfall intensity and snakebite incidences. Almost 6% of respondents had experienced a personal snakebite, whereas ~60% of respondents had witnessed a total of 799 snakebite cases. Out of a total of 857 reported snakebite cases, 24 (~2.8%) died. The highest snakebite prevalence was recorded for males in the age group 15–44 years during farming activities, with most bites occurring in the leg/foot region. The highest snakebite rate was within farmlands, most severe bites frequently caused by the Carpet viper (Echis ocellatus). Conclusion: The relatively high community-based prevalence of ~6%, and case fatality ratio of ~3%, indicate that snakebites represent an important public health risk in northern Ghana. Based on the high number of respondents and long recording period, we believe these data truly reflect the general situation in the rural northern savanna zone of Ghana and West Africa at large. We recommend increased efforts from both local and international health authorities to address the current snakebite health crisis generally compromising livelihoods and productivity of rural farming communities in West Africa. [ABSTRACT FROM AUTHOR]

A sensing principle, operating regime, and composition range are identified for force sensing with Galfenol alloys. Magnetization measurements of Fe79.1Ga20.9 and Fe81.6Ga18.4 are performed under applied magnetic field at constant stress. Stress-dependent, linear regions with negligible hysteresis are observed in the Fe79.1Ga20.9 sample over a large range of fields and stresses, for which an analytic model for unbiased loops is formulated. Similar regions are observed in the Fe81.6Ga18.4 sample, with a more limited stress and field range. The small signal operating regime (small in field, not in stress) centered about zero magnetic field is particularly advantageous because in this regime there is no observable hysteresis, since the magnetization process occurs by domain rotation only. The measurements and model show that in this region the susceptibility of Fe79.1Ga20.9 is more sensitive to stress (owing to a significantly lower fourth-order anisotropy constant) with only a small reduction in the saturation magnetization and magnetostriction as compared to Fe81.6Ga18.4. For force sensing, these results suggest the use of Galfenol with an ideal Ga content in the range of 19-22 at. % in which a small, positive fourth-order anisotropy constant is obtained, though in this composition range the magnetostriction is sacrificed. [ABSTRACT FROM AUTHOR]

We present a discrete energy-averaged model for the nonlinear and hysteretic relation of magnetization and strain to magnetic field and stress. Analytic expressions from energy minimization describe three-dimensional rotations of domains about easy crystal directions in regions where domain rotation is the dominant process and provide a means for direct calculation of magnetic anisotropy constants. The anhysteretic material behavior due to the combined effect of domain rotation and domain wall motion is described with an energy weighted average while the hysteretic material behavior is described with an evolution equation for the domain volume fractions. As a result of using a finite set of locally defined energy expressions rather than a single globally defined expression, the model is 100 times faster than previous energy weighting models and is accurate for materials with any magnetocrystalline anisotropy. The model is used to interpret magnetization and strain measurements of <100> oriented Fe79.1Ga20.9 and Fe81.5Ga18.5 as well as <110> oriented Fe81.6Ga18.4. [ABSTRACT FROM AUTHOR]

The growth of pentacene thin films for applications in thin-film transistors and other organic electronic devices results in a variety of extended structural defects including dislocations, grain boundaries, and stacking faults. We have used scanning tunneling microscopy (STM) to probe the molecular-scale structure of grain boundaries and stacking faults in a pentacene thin film on a Si (001) surface modified with styrene. Styrene/Si (001) substrates produce pentacene films that are structurally similar to those grown on insulating substrates, but which are sufficiently smooth and conductive for STM studies. STM images show two types of grain boundaries: in-plane high-angle tilt grain boundaries at the junctions between pentacene islands, and twist boundaries between molecular layers. Segments of the tilt grain boundaries are faceted along low-energy crystallographic directions. Stacking faults are found in the plane of individual pentacene grains. Two rows of molecules near the stacking fault are shifted along the surface normal by 60 pm. Electronically relevant trap states may thus be associated with stacking faults in pentacene thin films. [ABSTRACT FROM AUTHOR]

A fully coupled, nonlinear model is presented that characterizes the three-dimensional (3D) strain and magnetization response to magnetic field at constant stress in cubic magnetostrictive materials. A multiscale thermodynamic approach is taken which accounts for nonlinear anisotropy, material texture, and hysteresis effects. The model is validated with measurements of textured polycrystalline Galfenol. The model provides an efficient framework for characterization, design, and control of Galfenol (Fe–Ga) devices with 3D functionality subjected to combined magnetic field and stress loading. [ABSTRACT FROM AUTHOR]

The manipulation of strain in micromachined silicon structures presents an opportunity in the control of surface processes in epitaxial growth. With appropriate fabrication techniques, the magnitude, crystallographic direction, and symmetry of the strain at a Si surface can be precisely controlled with this strategy. Synchrotron x-ray microdiffraction techniques allow simultaneous independent measurements of the strain and bending in these structures and serve to calibrate the fabrication process. Bending is the dominant source of strain in a microfabricated Si bridge loaded at its ends by silicon nitride thin films that we have used as a strained substrate in studies of Ge epitaxial growth. The total strain difference between the top and bottom of the bent bridge exceeds 10-3 in present structures and can potentially be increased in optimized devices. These micromachined substrates complement other methods for producing strained silicon and silicon- germanium structures for improved electrical device performance and for fundamental studies of epitaxial growth. [ABSTRACT FROM AUTHOR]

When plasma immersion ion implantation is performed in the condensable plasma stream produced by a cathodic vacuum arc, deposition as well as implantation usually occurs. In this article we describe a method of achieving pure implantation by orienting the substrate so that it is shadowed from the plasma beam. Implantation depth profiles measured in glassy carbon and CR39 polymer using Rutherford backscattering are compared to illustrate the effectiveness of the technique for conducting and insulating substrates. Charging of the insulating substrate was found to cause a reduction in implantation depth compared to a conducting substrate. The depth profiles in glassy carbon were comparable to those achieved by conventional extracted ion beam implantation. Implantation of magnesium into hydroxyapatite and alumina was carried out to improve the bone cell adhesion onto these materials for prosthetic applications. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Highlights • A simple CAR salience 'shape' measure informed by secretory process is proposed. • It summarizes potency of secretion rate rise to and fall from peak. • It reflects amplitude of ultradian wave, possibly an important HPA feedback signal. • It discriminates seasonal affective disorder and control cases significantly better than AUCi. Abstract Pulsatile ultradian secretion of cortisol, rarely studied in salivary data, has functional importance in hypothalamic pituitary adrenal (HPA) axis regulation. The first daily ultradian episode, the cortisol awakening response (CAR), was examined in healthy adults, in 5-min secretion rates of salivary cortisol from electronically monitored awakening time to 1.25 h. Aggregated rates revealed a cubic trend, with wave-length of almost exactly 1 h, as predicted from known ultradian periodicity. Peak secretion rate occurred 20-min post-awakening. Peak (20-min) to trough (59-min) amplitude (PTA) expressed a salient signal shape. Rates rose steeply to and from peak, and major secretion was packaged into a few 5-min intervals, inconsistent with normal or uniform distribution of 5-min rates, but consistent with known pulsatile cortisol delivery. Null hypotheses asserting normal or uniform distributions were rejected. Maximal rates overwhelmingly occurred before and minimal rates after 30-mins, with degree of extremity at each polarity significantly positively correlated. To demonstrate utility and reliability of PTA estimation in a clinically relevant domain, re- analyses of a previously published study were conducted. Data from only three saliva samples were used, given importance of cost considerations for many CAR researchers. Difference between mean rates before and after 30-min yielded a simple salience index, highly correlated with PTA derived from full 5-min interval data. CAR salience performed significantly better than traditional AUCi magnitude in discriminating control cases (higher inferred amplitude) and cases with Seasonal Affective Disorder (lower inferred amplitude). Evidence suggested that low AUCi may be more sensitive in identifying within-subject changes (e.g. more depressed mood in winter among SAD cases) and low CAR salience better at revealing enduring between-subjects associations (e.g. underlying disorder vulnerability). Since both PTA salience and AUCi magnitude can be analysed and compared using exactly the same data from the same commonly used saliva sampling points, further research is warranted into the importance of individual differences in patterns of cortisol delivery, not just how much is delivered. [ABSTRACT FROM AUTHOR]

When a thin viscous film dewets from a solid substrate, the liquid forms a characteristic rim near the contact line as the contact line retracts. The shape of the rim and also the retraction rate vary strongly with the amount of slip that occurs at the liquid-solid substrate. If the slip length is very large compared to the thickness of the film, extensional stresses dominate the shear stresses, and the film evolution can be modeled by a thin-film model similar to the ones that occur in freely suspended films, with a correction from the viscous friction due to the large but finite slip. Asymptotic investigation of this model reveals that the rim has an amazingly rich asymptotic structure that moreover changes as the solution passes through four distinct time regimes. This paper continues previous work that focused on the first of these regimes [P. L. Evans, J. R. King, and A. Müunch, Appl. Math. Res. Express. AMRX, 2006 (2006), 25262]. The structure of the solution is analyzed in detail via matched asymptotics and then the predictions for the contact line and profile evolution are compared with numerical results. [ABSTRACT FROM AUTHOR]

Examines the compaction, distribution and chemical bonding of tungsten-implanted glassy carbon. Microstructure of glassy carbon; Effect of ion implantation on the resistance of glassy carbon; Rutherford backscattering spectrometry for various tungsten doses.

Focuses on a study which examined the transport of majority carriers across the potential barriers found at grain boundaries in semiconductors. Transport processes that were considered; Observation about boundary transport; Details of a numerical calculations for a given barrier height with a range of bulk doping levels; Evaluation of a deconvolution scheme to determine defect-state densities.

Describes a vacuum arc centrifuge (VAC) which produces a rapidly rotating metal plasma column by means of the Lorentz force between the arc current and an applied axial magnetic field. Types of sample analysis employed in the studies of mass separation in VAC; Components of VAC; Techniques employed to analyze the samples which were deposited on strips of aluminum foil in the plasma stream; Similarities of the copper/zinc system to that of aluminum/titanium.

Presents a study that examined the effects of hydrogen plasma erosion of glassy carbon implanted with tungsten. Use of Raman measurements; Background on glassy carbon; Role of tungsten in the inhibition of hydrogen plasma erosion.

A rhodium-catalyzed carbocyclization reaction of alkynylidenecyclopropanes with carbon monoxide to prepare bicyclohexa-2,5-dienones is described. This protocol offers convenient access to doubly conjugated cyclic enones and is tolerant of functionalized alkynes and cyclopropanes. Furthermore, a photochemical rearrangement of a bicyclohexa-2,5-dienone facilitates the construction of a highly functionalized bicyclopentenone containing two contiguous stereogenic centres, which represents a versatile intermediate for target directed synthesis. [ABSTRACT FROM AUTHOR]

The dawn of the gravitational-wave (GW) era has sparked a greatly renewed interest into possible links between sources of high-energy radiation and GWs. The most luminous high-energy sources--gammaray bursts (GRBs)--have long been considered as very likely sources of GWs, particularly from shortduration GRBs, which are thought to originate from the merger of two compact objects such as binary neutron stars and a neutron star-black hole binary. In this paper, we discuss: (i) the high-energy emission from short-duration GRBs; (ii) what other sources of high-energy radiation may be observed from binary mergers; and (iii) how searches for highenergy electromagnetic counterparts to GW events are performed with current space facilities. While current high-energy facilities, such as Swift and Fermi, play a crucial role in the search for electromagnetic counterparts, new spacemissions will greatly enhance our capabilities for joint observations. We discuss why such facilities, which incorporate new technology that enables very wide-field X-ray imaging, are required if we are to truly exploit the multi-messenger era. [ABSTRACT FROM AUTHOR]

The article offers information on research about conducting ultraviolet and x-ray observations by Swift and the Nuclear Spectroscopic Telescope Array of the electromagnetic counterpart called EM170817 of the binary neutron star merger and gravitational waves called GW170817. Other information is presented about gravitational wave astrophysics.

Ni, Co, and iron-rich FeNi films were grown onto n-GaAs (011) substrates using electrodeposition from metal sulfate solutions, at room temperature, with a current density of 3.5 mA/cm[SUP2]at a pH of 2.5. The structure of Ni film is found to be fcc with a (111) preferred orientation, whereas Co films show a mixed fcc and hcp structure that is confirmed by x-ray diffraction and transmission electron microscopy data. The structure of iron-rich (>90%) FeNi films remains unclear at the moment. The films show a well-defined, in-plane, uniaxial anisotropy with the easy axis along the [011] GaAs direction for Ni, and [01&sline;1] GaAs direction for Co and FeNi films (i.e., anisotropy rotated by 90° compared to Ni). Co films maintain their anisotropy even for large thicknesses (>250 nm) and so does Ni (up to 90 nm). Surprisingly, thin Ni films exhibit a larger H[SUBK] value(950 Oe) than what would be expected from a purely crystalline anisotropy. This effect is ascribed to internal stresses in the as-deposited films. [ABSTRACT FROM AUTHOR]

Using x-ray submicrobeam, we spatially mapped the strain in epitaxial La[sub l-χ]Sr[sub χ]MnO[sub 3] films grown on SrTiO[sub 3](001) bicrystal substrates. Our results show that there is an elastic strain gradient at the artificial grain boundary, which decays over a length scale of ∼1 µm. The tensile strain at the interior of the grain—due to the lattice mismatch between La[sub l-χ]Sr[sub χ]MnO[sub 3] and SrTiO[sub 3]—relaxes as the film nears the grain boundary, yielding a grain boundary lattice constant which approaches the value of that in bulk La[sub l-χ]Sr[sub χ]MnO[sub 3]. [ABSTRACT FROM AUTHOR]

We report on the detection of a bright, short, structured X-ray burst coming from the supernova remnant RCW 103 on 2016 June 22 caught by the Swift/Burst Alert Telescope (BAT) monitor, and on the follow-up campaign made with Swift/X-ray Telescope, Swift/UV/Optical Telescope, and the optical/near-infrared (NIR) Gamma-Ray burst Optical and Near-infrared Detector. The characteristics of this flash, such as duration and spectral shape, are consistent with typical short bursts observed from soft gamma repeaters. The BAT error circle at 68 per cent confidence range encloses the point-like X-ray source at the centre of the nebula, 1E 161348-5055. Its nature has been long debated due to a periodicity of 6.67 h in X-rays, which could indicate either an extremely slow pulsating neutron star, or the orbital period of a very compact X-ray binary system. We found that 20 min before the BAT trigger, the soft X-ray emission of 1E 161348-5055 was a factor of ~100 higher than measured 2 yr earlier, indicating that an outburst had already started. By comparing the spectral and timing characteristics of the source in the 2 yr before the outburst and after the BAT event, we find that, besides a change in luminosity and spectral shape, also the 6.67 h pulsed profile has significantly changed with a clear phase shift with respect to its low-flux profile. The UV/optical/NIR observations did not reveal any counterpart at the position of 1E 161348-5055. Based on these findings, we associate the BAT burst with 1E 161348-5055, we classify it as a magnetar, and pinpoint the 6.67 h periodicity as the magnetar spin period. [ABSTRACT FROM AUTHOR]

A highly enantioselective rhodium-catalyzed allylic alkylation of prochiral α,α-disubstituted aldehyde enolates with allyl benzoate is described. This protocol provides a novel approach for the synthesis of acyclic quaternary carbon stereogenic centers and it represents the first example of the direct enantioselective alkylation of an aldehyde enolate per se. The versatility of the α-quaternary aldehyde products is demonstrated through their conversion to a variety of useful motifs applicable to target-directed synthesis. Finally, mechanistic studies indicate that high levels of asymmetric induction are achieved from a mixture of prochiral (E)- and (Z)-enolates, which provides an exciting development for this type of transformation. [ABSTRACT FROM AUTHOR]

Wood composites undergo irreversible thickness swelling and strength losses when they are exposed to water, and there is strong interest in developing cost-effective solutions to this problem. We hypothesised that a composite with more adhesive connections in theZ-(thickness)-direction would be less susceptible to thickness swelling. We test this hypothesis using a model composite consisting of perforated veneer that allowed a polyurethane adhesive to create cross-links in theZ-direction. Model composite specimens were submerged in water, air-dried and their irreversible thickness swelling and surface topography were measured.Z-direction cross-links significantly reduced the thickness swelling of both yellow cedar and white spruce specimens, but the inter-connected adhesive network retained its integrity better in spruce than in cedar specimens. Further research is needed to develop practical ways of creatingZ-direction cross-links in composites that resemble commercial products, and also to evaluate the effects they have on the mechanical properties of composites. [ABSTRACT FROM AUTHOR]

During its first observing run, in late 2015, the advanced Laser Interferometer Gravitationalwave Observatory facility announced three gravitational wave (GW) triggers to electromagnetic follow-up partners. Two of these have since been confirmed as being of astrophysical origin: both are binary black hole mergers at ~500 Mpc; the other trigger was later found not to be astrophysical. In this paper, we report on the Swift follow-up observations of the second and third triggers, including details of 21 X-ray sources detected; none of which can be associated with the GW event. We also consider the challenges that the next GW observing run will bring as the sensitivity and hence typical distance of GW events will increase. We discuss how to effectively use galaxy catalogues to prioritize areas for follow-up, especially in the presence of distance estimates from the GW data. We also consider two galaxy catalogues and suggest that the high completeness at larger distances of the 2MASS Photometric Redshift catalogue makes it very well suited to optimize Swift follow-up observations. [ABSTRACT FROM AUTHOR]

The temporary silicon-tethered ring-closing metathesis of chiral non-racemic allylic and homoallylic alcohols affords unsymmetrical Z-configured trisubstituted olefins that readily undergo stereoselective hydroboration and dihydroxylation to provide a novel approach to masked polypropionate and polyol fragments present in an array of biologically important natural products. For example, this strategy provides a convenient method for the construction of polyol fragments relevant to the secondary metabolites amphidinol 3 and lophodiol A, which have antifungal and cytotoxic activity, respectively. [ABSTRACT FROM AUTHOR]

Provides information on a study that presented data demonstrating the effect that cavity length, and thus Q loss, has upon quantum well heterostructure edge-emitting laser diodes that are reduced to microcavity thickness. Details on the fabrication of the edge-emitting lasers; Results and discussion on the study.

Introduction Self-determination theory postulates that the three basic psychological needs of autonomy, competence and relatedness have to be satisfied for students to achieve intrinsic motivation and internalisation of autonomous self-regulation towards academic activities. Consequently, the influence of the clinical teaching environment becomes crucial when satisfying these needs, particularly when promoting or diminishing students' intrinsic motivation. The aim of this study was to describe and understand how clinical teachers encourage intrinsic motivation in undergraduate dental students based on the three basic psychological needs described by the self-determination theory. Methods A qualitative case study approach was adopted, and data were collected through semistructured interviews with nine experienced undergraduate clinical teachers of one dental school in Santiago, Chile. Interview transcripts were analysed by two independent reviewers using a general inductive approach. Findings Several themes emerged outlining teaching strategies and behaviours. These themes included the control of external motivators; gradual transference of responsibility; identification and encouragement of personal interests; timely and constructive feedback; delivery of a vicarious learning experience; teamwork, team discussion, and presence of a safe environment, amongst others. Overall, teachers stressed the relevance of empowering, supporting and building a horizontal relationship with students. Conclusions Our findings regarding dental education expand on the research outcomes from other health professions about how teachers may support students to internalise behaviours. An autonomy-supportive environment may lead students to value and engage in academic activities and eventually foster the use of an autonomy-supportive style to motivate their patients. [ABSTRACT FROM AUTHOR]

We hypothesise that end-grain (transverse) wood surfaces will erode less during natural weathering than side-grain (radial and tangential longitudinal) surfaces. Douglas fir samples were exposed to 10 000 hours of weathering, and confocal profilometry was used to measure depth of erosion of the different planar surfaces. End-grain eroded less than side-grain, but the difference in erosion of end-grain and radial surfaces was only statistically significant if voids in end-grain created by checks were excluded from erosion measurements. Tangential surfaces were the most susceptible to erosion, due in part to the presence of lens-shaped voids caused by erosion of ray tissues. Erosion of earlywood was greater than that of latewood, particularly for end-grain. Erosion of earlywood is caused by thinning of cell walls in combination with transverse and longitudinal micro-checking, which creates loosely bonded cell wall fragments at weathered wood surfaces. We conclude that end-grain erodes less than side-grain surfaces when exposed to weathering, but differences in erosion of these planar surfaces is affected by checking, which complicates measurement of the erosion of wood using confocal profilometry. We discuss this issue, and describe the practical implications of our findings for the use of wooden posts as boundary markers for mining leases. [ABSTRACT FROM PUBLISHER]

This paper reviews the effects of incising on the checking of wood. I describe the early research that led to the development and widespread adoption of incising technology as a way of ensuring that preservatives penetrate impermeable woods more deeply and evenly. The terms checking, cracking and splitting are defined and the important effects of checking on the performance of different wood products are described. The review then focusses on the effects of incising on the checking of wood. I describe the effects of incising on the development of drying and weathering checks in railway sleepers (ties), poles, posts and structural and appearance-grade timber. I describe the mechanisms that are responsible for the positive effects of incising on checking and conclude the review by summarising the effects of incising on the checking of wood, and suggesting how the technology may diffuse and evolve in the future. [ABSTRACT FROM PUBLISHER]

One of the most exciting near-term prospects in physics is the potential discovery of gravitational waves by the Advanced LIGO and Virgo detectors. To maximize both the confidence of the detection and the science return, it is essential to identify an electromagnetic counterpart. This is not trivial, as the events are expected to be poorly localized, particularly in the near-term, with error regions covering hundreds or even thousands of square degrees. In this paper, we discuss the prospects for finding an X-ray counterpart to a gravitational wave trigger with the Swift X-ray Telescope, using the assumption that the trigger is caused by a binary neutron star merger which also produces a short gamma-ray burst. We show that it is beneficial to target galaxies within theGWerror region, highlighting the need for substantially complete galaxy catalogues out to distances of 300 Mpc. We also show that nearby, on-axis short GRBs are either extremely rare, or are systematically less luminous than those detected to date. We consider the prospects for detecting afterglow emission from an off-axis GRB which triggered the GW facilities, finding that the detectability, and the best time to look, are strongly dependent on the characteristics of the burst such as circumburst density and our viewing angle. [ABSTRACT FROM AUTHOR]

High strength low alloy steels are characterised by predominantly ferritic microstructures, strengthened by grain boundary and precipitation strengthening. Both of these strengthening mechanisms traditionally arise from the niobium addition. Increasing the niobium addition would theoretically increase strength. However, increasing niobium content above ~ 0.04 wt.% is not recommended in industrial practice due to narrowing of the annealing process window. Two novel grades exhibiting different additions of titanium and vanadium in place of the traditional niobium addition were investigated. Sensitivity to annealing linespeed and soak temperature was investigated to conclude whether a practically achievable process window exists and moreover, to conclude whether proof strength in excess of 420 MPa could be achieved while satisfying the maximum ultimate tensile strength and minimum total elongation specifications of CEN Grade HC420LA under European Standard EN 10268:2006. One of the two novel grades, exhibiting higher manganese and vanadium contents, met the minimum proof strength target, while almost satisfying the maximum ultimate tensile strength and minimum total elongation specifications. However, the annealed microstructure was found to be partially recrystallised, which is not recommended in industrial practice. Moreover, sensitivity to annealing linespeed and soak temperature was considered too great to obtain a practically achievable process window. [ABSTRACT FROM AUTHOR]

National efforts to reduce energy dependency on fossil fuels have prompted examination of macrotidal nearshore sites around the United Kingdom (UK) for potential tidal stream resource development. A number of prospective tidal energy sites have been identified, but the local hydrodynamics of these sites are often poorly understood. Tidal energy developers rely on detailed characterisation of tidal energy sites prior to device installation and field trials. Although first-order appraisals may make macrotidal tidal straits appear attractive for development, detailed, site-specific hydrodynamic and bathymetric surveys are important for determining site suitability for tidal stream turbine (TST) installation. Understanding the ways in which coastal features affect tidal velocities at potential TST development sites will improve identification and analysis of physical constraints on tidal energy development. This paper presents and examines tidal velocity data measured in Ramsey Sound (Pembrokeshire, Wales, UK), an energetic macrotidal strait, which will soon host Wales' first TST demonstration project. While maximum tidal velocities in the strait during peak spring flood exceed 3 m s −1 , the northern portion of Ramsey Sound exhibits a marked flood-dominated tidal asymmetry. Furthermore, local bathymetric features affect flow fields that are spatially heterogeneous in three dimensions, patterns that depth-averaged velocity data (measured and modelled) tend to mask. Depth-averaging can therefore have a significant effect on power estimations. Analysis of physical and hydrodynamic characteristics in Ramsey Sound, including tidal velocities across the swept area of the pilot TST, variations in the stream flow with depth, estimated power output, water depth and bed slope, suggests that the spatial and temporal variability in the flow field may render much of Ramsey Sound unsuitable for tidal power extraction. Although the resource potential depends on velocity and bathymetric conditions that are fundamentally local, many prospective tidal energy sites are subject to similar physical and hydrodynamic constraints. Results of this study can help inform site selection in these complicated, highly dynamic macrotidal environments. In order to fully characterise the structure of the tidal currents, these data should be supplemented with 3-D modelling, particularly in areas subject to a highly irregular bathymetry and complicated tidal regime. [ABSTRACT FROM AUTHOR]

Describes the case of a male patient in whom the majority of features present are in keeping with a diagnosis of Alstrom's syndrome. Patient's mild mental retardation and a 47XXY karyotype; Localization of the genetic defect in Alstrom's syndrome; Determination of whether the association with the Kleinfelters karyotype.

Although there is considerable evidence that individual differences in language development are highly heritable, there have been few genome-wide scans to locate genes associated with the trait. Previous analyses of language impairment have yielded replicable evidence for linkage to regions on chromosomes 16q, 19q, 13q (within lab) and at 13q (between labs). Here we report the first linkage study to screen the continuum of language ability, from normal to disordered, as found in the general population. 383 children from 147 sib-ships (214 sib-pairs) were genotyped on the Illumina® Linkage IVb Marker Panel using three composite language-related phenotypes and a measure of phonological memory ( PM). Two regions (10q23.33; 13q33.3) yielded genome-wide significant peaks for linkage with PM. A peak suggestive of linkage was also found at 17q12 for the overall language composite. This study presents two novel genetic loci for the study of language development and disorders, but fails to replicate findings by previous groups. Possible reasons for this are discussed. [ABSTRACT FROM AUTHOR]

A direct and highly enantioselective rhodium-catalyzed allylic alkylation of allyl benzoate with asubstituted benzyl nitrile pronucleophiles is described. This simple protocol provides a new approach toward the synthesis of acyclic quaternary carbon stereogenic centers and provides the first example of the direct asymmetric alkylation of a nitrile anion. The synthetic utility of the nitrile products is amply demonstrated through conversion to various functional groups and the synthesis of a bioactive aryl piperazine in an expeditious four-step sequence. [ABSTRACT FROM AUTHOR]

Between 2011 March and 2014 August Swift responded to 20 triggers from the IceCube neutrino observatory, observing the IceCube 50 per cent confidence error circle in X-rays, typically within 5 h of the trigger. No confirmed counterpart has been detected. We describe the Swift follow-up strategy and data analysis and present the results of the campaign. We discuss the challenges of distinguishing the X-ray counterpart to a neutrino trigger from serendipitous uncatalogued X-ray sources in the error circle, and consider the implications of our results for future strategies for multimessenger astronomy, with particular reference to the follow-up of gravitational wave triggers from the advanced-era detectors. [ABSTRACT FROM AUTHOR]

The development of the stereoselective rhodium-catalyzed [(3+2)+2] carbocyclization of alkynylidenecyclopropanes (ACPs) with substituted allenes is described. This work demonstrates that activated and unactivated allenes preferentially undergo carbometalation at the distal terminus to generate tri- and tetrasubstituted exocyclic olefins with a neutral rhodium catalyst. In addition, this method provides a strategy for the total synthesis of the guaiane family of sesquiterpenes, which are not directly accessible using alkynes as exogenous π-components. Finally, the preparation of the bicyclo[5.4.0]undecane ring system using a homologated ACP tether serves to further illustrate the versatility of this approach. [ABSTRACT FROM AUTHOR]

The development of the stereoselective rhodium-catalyzed [(3+2)+2] carbocyclization of alkynylidenecyclopropanes (ACPs) with substituted allenes is described. This work demonstrates that activated and unactivated allenes preferentially undergo carbometalation at the distal terminus to generate tri- and tetrasubstituted exocyclic olefins with a neutral rhodium catalyst. In addition, this method provides a strategy for the total synthesis of the guaiane family of sesquiterpenes, which are not directly accessible using alkynes as exogenous π-components. Finally, the preparation of the bicyclo[5.4.0]undecane ring system using a homologated ACP tether serves to further illustrate the versatility of this approach. [ABSTRACT FROM AUTHOR]

We present the first follow-up study of the transiting system WASP-41 after its discovery in 2011. The main goal of this paper is to refine the physical parameters of the system and search for possible signs of transit timing variations. The observations used for analysis were taken from the public archive of the Exoplanet Transit Database (ETD). Assuming three different limb darkening laws, we found the best-fitting model and redetermined parameters of the system. Although system parameters obtained in this study were found to be in good agreement with the discovery study, the planetary radius determined here is notably smaller, namely 1.12+0.06 -0.07 RJup. The Safronov number Θ = 0.071 ± 0.002 and equilibrium temperature Teq = 1271 ± 50 K were also determined. Both values indicate that the planet WASP-41b belongs to Class I of transiting planets. No significant transit timing variations were detected. (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

GRB 130925A was an unusual gamma ray burst (GRB), consisting of three distinct episodes of high-energy emission spanning ∼20 ks, making it a member of the proposed category of ‘ultralong’ bursts. It was also unusual in that its late-time X-ray emission observed by Swift was very soft, and showed a strong hard-to-soft spectral evolution with time. This evolution, rarely seen in GRB afterglows, can be well modelled as the dust-scattered echo of the prompt emission, with stringent limits on the contribution from the normal afterglow (i.e. external shock) emission. We consider and reject the possibility that GRB 130925A was some form of tidal disruption event, and instead show that if the circumburst density around GRB 130925A is low, the long duration of the burst and faint external shock emission are naturally explained. Indeed, we suggest that the ultralong GRBs as a class can be explained as those with low circumburst densities, such that the deceleration time (at which point the material ejected from the nascent black hole is decelerated by the circumburst medium) is ∼20 ks, as opposed to a few hundred seconds for the normal long GRBs. The increased deceleration radius means that more of the ejected shells can interact before reaching the external shock, naturally explaining both the increased duration of GRB 130925A, the duration of its prompt pulses, and the fainter-than-normal afterglow. [ABSTRACT FROM PUBLISHER]

Thedevelopment of the rhodium-catalyzed [(3+2)+1] carbocyclizationreaction of alkynylidenecyclopropanes with carbonmonoxide to construct polysubstituted phenols is described. This workoffers a convenient method for the selective formation of tetra- andpentasubstituted phenols, which provide important intermediates fortarget directed synthesis. Finally, the ability to regiospecificallyfunctionalize the phenols using conventional methods further illustratesthe utility of this process. [ABSTRACT FROM AUTHOR]

We report the facile and efficient metal-free metathesis reaction of C-chiral allylic sulfilimines with aryl isocyanates. This process facilitates the room temperature construction of an array of chiral nonracemic allylic isocyanates, which are versatile intermediates for the construction of unsymmetrical ureas, carbamates, thiocarbamates and amides. Furthermore, the sulfilimine/ isocyanate metathesis reaction with 4,4'-methylene diphenyl diisocyanate (4,4'-MDI) circumvents harsh reaction conditions and/or hazardous reagents employed with more classical methods for the preparation of this important functional group. [ABSTRACT FROM AUTHOR]

We have developed a competitor-based RT-PCR technique which will detect and quantitate the CBFbeta/MYH11 transcripts associated with inv(16)(q22;p13) and have used it to study presentation and follow-up samples of acute myeloid leukaemia (AML). The levels of the leukaemia-specific transcripts are expressed as a ratio to a ubiquitously expressed mRNA species (Abl) which controls for RNA degradation. This technique has been applied to 75 consecutive patients presenting with either de novo AML or tMDS; 6/75 patients analysed were positive for the inv(16), all were confirmed by conventional cytogenetics. The inv(16) has a strong association with M4Eo, but we found only 2/6-positive patients to have this diagnosis (two patients with M2, one patient M1 and one patient had MDS). At presentation the levels of CBFbeta/MYH11 transcripts were 0.1-10/Abl transcript (mean 3.3/Abl transcript). Seventeen follow-up samples were available on 5/6 of these patients, and on two further patients in whom stored material was available. Following the first cycle of chemotherapy the level of transcripts was at least 10(-2) lower (0.1-10 x 10(-2)/abl transcript) than their presentation sample. Subsequent samples on these patients when in remission gave transcript levels in the range (1.0 x 10(-4) - 2 x 10(-3)/abl transcript), and three long-term follow-up samples were negative. We have developed a quantitative test which opens the possibility of predicting relapse by detecting changes in the numbers of leukaemia-specific transcripts. [ABSTRACT FROM AUTHOR]