X-ray Observations of XSS J12270-4859 in a New Low State: A Transformation to a Disk-Free Rotation-Powered Pulsar Binary

We present XMM-Newton and Chandra observations of the low-mass X-ray binary XSS J12270--4859, which experienced a dramatic decline in optical/X-ray brightness at the end of 2012, indicative of the disappearance of its accretion disk. In this new state, the system exhibits previously absent orbital-phase-dependent, large-amplitude X-ray modulations with a decline in flux at superior conjunction. The X-ray emission remains predominantly non-thermal but with an order of magnitude lower mean luminosity and significantly harder spectrum relative to the previous high flux state. This phenomenology is identical to the behavior of the radio millisecond pulsar binary PSR J1023+0038 in the absence of an accretion disk, where the X-ray emission is produced in an intra-binary shock driven by the pulsar wind. This further demonstrates that XSS J12270-4859 no longer has an accretion disk and has transformed to a full-fledged eclipsing "redback" system that hosts an active rotation-powered millisecond pulsar. There is no evidence for diffuse X-ray emission associated with the binary that may arise due to outflows or a wind nebula. An extended source situated 1.5' from XSS J12270--4859 is unlikely to be associated, and is probably a previously uncatalogued galaxy cluster.Comment: 8 pages, 6 figures; accepted for publication in the Astrophysical Journa

Development of PDT/PET theranostics: synthesis and biological evaluation of an ¹⁸F-radiolabeled water soluble porphyrin

Synthesis of the first water-soluble porphyrin radiolabeled with fluorine-18 is described: a new molecular theranostic agent which integrates the therapeutic selectivity of photodynamic therapy (PDT) with the imaging efficacy of positron emission tomography (PET). Generation of the theranostic was carried out through the conjugation of a cationic water-soluble porphyrin bearing an azide functionality to a fluorine-18 radiolabeled prosthetic bearing an alkyne functionality through click conjugation, with excellent yields obtained in both cold and hot synthesis. Biological evaluation of the synthesized structures shows the first example of an 18 F-radiolabeled porphyrin retaining photocytotoxicity following radiolabeling and demonstrable conjugate uptake and potential application as a radiotracer in vivo. The promising results gained from biological evaluation demonstrate the potential of this structure as a clinically relevant theranostic agent, offering exciting possibilities for the simultaneous imaging and photodynamic treatment of tumors

Forage from cropping systems as dry season supplements for sheep

Information on the utilisation of legume hays from an intercropping system as a feed supplement is limited. Three forage legume hays (Stylosanthes guianensis, Lablab purpureus and Aeschynomene histrix) were compared by feeding them as supplements for yearling West African Dwarf rams (LWt 18.0±2.2 kg) fed a basal diet of mature guinea grass (Panicum maximum). The performance of the rams was evaluated in a 60-day growth trial, using a completely randomised design with 6 rams per treatment. Organic matter digestibility and nitrogen retention were assessed in a separate trial using the same design; but with 4 animals per treatment. In the growth trial, rams supplemented with S. guianensis and A. histrix gained more weight (P<0.05) than those on the L. purpureus supplemented diet. Average total weight gains were 33.3, 13.2 and 31.2 g/d for S. guianensis-, L. purpureus- and A. histrix-supplemented diets, respectively. Organic matter digestibility was 643, 568 and 523 g/kg for S. guianensis-, A. histrix- and L. purpureus-supplemented groups, respectively. All treatments resulted in positive nitrogen balance. We concluded that feeding forage legumes from cereal-based cropping systems as a supplement can maintain liveweight in sheep and even achieve modest weight gains during the critical dry period when feed quality is poor

Knowledge Translation of Interprofessional Collaborative Patient-Centred Practice: The Working Together Project Experience

The Working Together (WT) project involved the design and delivery of an online learning resource for healthcare teams in long-term care (LTC) so that knowledge regarding interprofessional collaborative patient-centred practice (ICPCP) could be readily accessed and then transferred to the workplace. The purpose of this paper is to better understand the process of knowledge translation in continuing education for healthcare professionals by documenting our experiences using Lavis et al.’s (2003) organizing framework for knowledge transfer, and highlighting the impact this approach had on the design, development, delivery, and evaluation of the WT program. Fifty-nine pharmacists, physicians, nurses, and nurse practitioners from 17 LTC homes across Ontario, Canada participated in this project. The effectiveness of the knowledge translation of ICPCP through the WT project was evaluated using the Demand-Driven Learning Model (DDLM) evaluation tool (MacDonald, Breithaupt, Stodel, Farres, & Gabriel, 2002) to assess learners’ reactions to the learning resource. Data from quantitative pre-post surveys and qualitative interviews revealed that learners found using the WT online resource to be a satisfactory learning experience, obtained new knowledge and skills regarding ICPCP, transferred knowledge to the workplace, and reported that learning had a positive effect on the residents they cared for.Le projet Working Together (WT) comprend la conception et la production d’une ressource d’apprentissage en ligne pour les équipes de professionnels prodiguant des soins de santé de longue durée (SLD) afin que les connaissances relatives à la pratique interprofessionnelle en collaboration axée sur le patient (PICAP) puissent être facilement accessibles, puis transférées dans le milieu de travail. L’objectif de cet article est de mieux comprendre le processus d’application des connaissances dans la formation continue des professionnels de la santé en documentant notre expérience à l’aide de Lavis et coll. (2003), en établissant un cadre théorique pour le transfert des connaissances et en mettant en évidence l’incidence de cette approche sur la conception, le développement, la réalisation et l’évaluation du programme WT. Cinquante-neuf pharmaciens, médecins, infirmiers et infirmières, infirmiers et infirmières praticiens de 17 centres de SLD en Ontario, au Canada, ont participé à ce projet. L’efficacité de l’application des connaissances de la PICAP à l’échelle du projet WT a été évaluée à l’aide du modèle d’apprentissage axé sur la demande (DDLM) (MacDonald, Breithaupt, Stodel, Farres et Gabriel, 2002) afin de déterminer les réactions des apprenants à la ressource d’apprentissage. Des données tirées de prétest et de postest quantitatifs ainsi que d’entrevues qualitatives ont révélé que les apprenants étaient satisfaisants de l’expérience d’apprentissage que procure la ressource en ligne WT, qu’ils ont acquis de nouvelles connaissances et aptitudes concernant la PICAP et mis en application ces connaissances dans leur milieu de travail, et que l’apprentissage a eu un effet positif sur les pensionnaires dont ils prennent soin

How does iron interact with sporopollenin exine capsules? An X-ray absorption study including microfocus XANES and XRF imaging

Sporopollenin exine capsules (SECs) derived from plant spores and pollen grains have been proposed as adsorption, remediation and drug delivery agents. Despite many studies there is scant structural data available. This X-ray absorption investigation represents the first direct structural data on the interaction of metals with SECs and allows elucidation of their structure–property relationships. Fe K-edge XANES and EXAFS data have shown that the iron local environment in SECs (derived from Lycopodium clavatum) reacted with aqueous ferric chloride solutions is similar to that of ferrihydrite (FeOOH) and by implication ferritin. Fe Kα XRF micro-focus experiments show that there is a poor correlation between the iron distribution and the underlying SEC structure indicating that the SEC is coated in the FeOOH material. In contrast, the Fe Kα XRF micro-focus experiments on SECs reacted with aqueous ferrous chloride solutions show that there is a very high correlation between the iron distribution and the SEC structure, indicating a much more specific form of interaction of the iron with the SEC surface functional groups. Fe K-edge XANES and EXAFS data show that the FeII can be easily oxidised to give a structure similar to, but not identical to that in the FeIII case, and that even if anaerobic conditions are used there is still partial oxidation to FeIII

What Limits Fire? An Examination of Driver\u27s of Burnt Area in Southern Africa

The factors controlling the extent of fire in Africa south of the equator were investigated using moderate resolution (500 m) satellite-derived burned area maps and spatial data on the environmental factors thought to affect burnt area. A random forest regression tree procedure was used to determine the relative importance of each factor in explaining the burned area fraction and to address hypotheses concerned with human and climatic influences on the drivers of burnt area. The model explained 68% of the variance in burnt area. Tree cover, rainfall in the previous 2 years, and rainfall seasonality were the most important predictors. Human activities – represented by grazing, roads per unit area, population density, and cultivation fraction – were also shown to affect burnt area, but only in parts of the continent with specific climatic conditions, and often in ways counter to the prevailing wisdom that more human activity leads to more fire. The analysis found no indication that ignitions were limiting total burnt area on the continent, and most of the spatial variation was due to variation in fuel load and moisture. Split conditions from the regression tree identified (i) low rainfall regions, where fire is rare; (ii) regions where fire is under human control; and (iii) higher rainfall regions where burnt area is determined by rainfall seasonality. This study provides insights into the physical, climatic, and human drivers of fire and their relative importance across southern Africa, and represents the beginnings of a predictive framework for burnt area

Evidence of strong stabilizing effects on the evolution of boreoeutherian (Mammalia) dental proportions.

The dentition is an extremely important organ in mammals with variation in timing and sequence of eruption, crown morphology, and tooth size enabling a range of behavioral, dietary, and functional adaptations across the class. Within this suite of variable mammalian dental phenotypes, relative sizes of teeth reflect variation in the underlying genetic and developmental mechanisms. Two ratios of postcanine tooth lengths capture the relative size of premolars to molars (premolar-molar module, PMM), and among the three molars (molar module component, MMC), and are known to be heritable, independent of body size, and to vary significantly across primates. Here, we explore how these dental traits vary across mammals more broadly, focusing on terrestrial taxa in the clade of Boreoeutheria (Euarchontoglires and Laurasiatheria). We measured the postcanine teeth of N = 1,523 boreoeutherian mammals spanning six orders, 14 families, 36 genera, and 49 species to test hypotheses about associations between dental proportions and phylogenetic relatedness, diet, and life history in mammals. Boreoeutherian postcanine dental proportions sampled in this study carry conserved phylogenetic signal and are not associated with variation in diet. The incorporation of paleontological data provides further evidence that dental proportions may be slower to change than is dietary specialization. These results have implications for our understanding of dental variation and dietary adaptation in mammals

Comment on ``Measurement of the 3^3He mass diffusion coefficient in superfluid 4^4He over the 0.45--0.95 K temperature range

The role of 3He-3He collisions in our diffusion experiment is addressed and shown to not be relevant to the measurement of 3He diffusion against phonons in superfluid helium.Comment: Two pages, in Europhysics Letters forma

NuSTAR Observations of the Magnetar 1E 2259+586

We report on new broad band spectral and temporal observations of the magnetar 1E 2259+586, which is located in the supernova remnant CTB 109. Our data were obtained simultaneously with the Nuclear Spectroscopic Telescope Array (NuSTAR) and Swift, and cover the energy range from 0.5-79 keV. We present pulse profiles in various energy bands and compare them to previous RXTE results. The NuSTAR data show pulsations above 20 keV for the first time and we report evidence that one of the pulses in the double-peaked pulse profile shifts position with energy. The pulsed fraction of the magnetar is shown to increase strongly with energy. Our spectral analysis reveals that the soft X-ray spectrum is well characterized by an absorbed double-blackbody or blackbody plus power-law model in agreement with previous reports. Our new hard X-ray data, however, suggests that an additional component, such as a power-law, is needed to describe the NuSTAR and Swift spectrum. We also fit the data with the recently developed coronal outflow model by Beloborodov for hard X-ray emission from magnetars. The outflow from a ring on the magnetar surface is statistically preferred over outflow from a polar cap.Comment: 37 pages, 9 figures, corresponding author, [email protected]