A periodically active pulsar giving insight into magnetospheric physics

PSR B1931+24 (J1933+2421) behaves as an ordinary isolated radio pulsar during active phases that are 5 to 10 days long. However, when the radio emission ceases, it switches off in less than 10 seconds and remains undetectable for the next 25 to 35 days, then switches on again. This pattern repeats quasi-periodically. The origin of this behavior is unclear. Even more remarkably, the pulsar rotation slows down 50% faster when it is on than when it is off. This indicates a massive increase in magnetospheric currents when the pulsar switches on, proving that pulsar wind plays a substantial role in pulsar spin-down. This allows us, for the first time, to estimate the magnetospheric currents in a pulsar magnetosphere during the occurrence of radio emission.     

Girdling and the reduction in shoot xylem sap concentrations of cytokinins and gibberellins in peach

The effects of girdling at the beginning of pit hardening on peach shoot xylem sap cytoki- nin and gibberellin concentrations were studied. Girdling at the beginning of growth stage II of fruit development significantly reduced xylem sap concentration of zeatin-type cytokinins, gibberellin A, and/or gibberellin A3. Girdling also reduced shoot growth, both internodal length and node number, for about eight weeks after girdling until the girdle had healed over. The results support the hypothesis that reduced shoot growth is caused by reduced xylem transported, root supplied, promotive growth substances.     

Transformation of a star into a planet in a millisecond pulsar binary

Millisecond pulsars are thought to be neutron stars that have been spun-up by accretion of matter from a binary companion. Although most are in binary systems, some 30% are solitary, and their origin is therefore mysterious. PSR J1719-1438, a 5.7-millisecond pulsar, was detected in a recent survey with the Parkes 64-meter radio telescope. We show that this pulsar is in a binary system with an orbital period of 2.2 hours. The mass of its companion is near that of Jupiter, but its minimum density of 23 grams per cubic centimeter suggests that it may be an ultralow-mass carbon white dwarf. This system may thus have once been an ultracompact low-mass x-ray binary, where the companion narrowly avoided complete destruction.     

Multispecies fisheries management and conservation: tactical applications using models of intermediate complexity

Stakeholders increasingly expect ecosystem assessments as part of advice on fisheries management. Quantitative models to support fisheries decision‐making may be either strategic (‘big picture’, direction‐setting and contextual) or tactical (focused on management actions on short timescales), with some strategic models informing the development of tactical models. We describe and review ‘Models of Intermediate Complexity for Ecosystem assessments’ (MICE) that have a tactical focus, including use as ecosystem assessment tools. MICE are context‐ and question‐driven and limit complexity by restricting the focus to those components of the ecosystem needed to address the main effects of the management question under consideration. Stakeholder participation and dialogue is an integral part of this process. MICE estimate parameters through fitting to data, use statistical diagnostic tools to evaluate model performance and account for a broad range of uncertainties. These models therefore address many of the impediments to greater use of ecosystem models in strategic and particularly tactical decision‐making for marine resource management and conservation. MICE are capable of producing outputs that could be used for tactical decision‐making, but our summary of existing models suggests this has not occurred in any meaningful way to date. We use a model of the pelagic ecosystem in the Coral Sea and a linked catchment and ocean model of the Gulf of Carpentaria, Australia, to illustrate how MICE can be constructed. We summarize the major advantages of the approach, indicate opportunities for the development of further applications and identify the major challenges to broad adoption of the approach.     

A Rapid Method for Quantitation of Insoluble Polymeric Proteins in Flour

The baking properties of several genotypes of U.S. hard wheats grown in state nurseries for the Wheat Quality Council (WQC) were analyzed by the Hard Winter Wheat Quality Laboratory. Flours (250 mg) from each individual line and location were extracted three times with 50% 1- propanol (1 mL) for 5 min each. Samples were vortexed continually during extraction. This method was effective in removing most monomeric proteins. Negligible detectable protein was found in the third extract. Significant amounts of polymeric glutenin were also extracted. Pellets were oven-dried (130°C) for 1 hr and analyzed for protein content using nitrogen combustion analysis. Protein remaining in the pellet consisted mainly of polymeric protein. The amount of gliadin and soluble polymeric protein could also be measured by separating the supernatant by size-exclusion chromatography. Good correlations between dough strength parameters and amounts of pellet protein and the relative amount of pellet protein (pellet protein/flour protein) were found for all samples. This procedure was simple and rapid, with the potential of analyzing large numbers of samples per day with good reproducibility.     

Community economies in Monsoon Asia: Keywords and key reflections

A diversity of place‐based community economic practices that enact ethical interdependence has long enabled livelihoods in Monsoon Asia. Managed either democratically or coercively, these culturally inflected practices have survived the rise of a cash economy, albeit in modified form, sometimes being co‐opted to state projects. In the modern development imaginary, these practices have been positioned as ‘traditional’, ‘rural’ and largely superseded. But if we read against the grain of modernisation, a largely hidden geography of community economic practices emerges. This paper introduces the project of documenting keywords of place‐based community economies in Monsoon Asia. It extends Raymond William’s cultural analysis of keywords into a non‐western context and situates this discursive approach within a material semiotic framing. The paper has been collaboratively written with co‐researchers across Southeast Asia and represents an experimental mode of scholarship that aims to advance a post‐development agenda.     

Growth performance of piglets during the first two weeks of lactation affects the development of the intestinal microbiota

The aim of this study was to evaluate the effect of newborn piglet weight gain during the first 2 weeks of lactation on the luminal and mucosal microbiota of the ileum and colon. The microbiota from high‐weight‐gain (HWG) and low‐weight‐gain (LWG) 2‐week‐old piglets was characterized by amplicon length heterogeneity PCR (LH‐PCR) and compared using diversity indices and multivariate statistical analyses. At birth, LWG piglets weighted in average 0.26 kg less than HWG piglets (p = .002). The weight difference between LWG and HWG piglets increased with time and reached 2.1 kg after 16 days of lactation (p < .0001). Based on these growth performance differences, estimated colostrum and milk intake was greater in HWG than in LWG piglets (p < .0001). Analysis of the LH‐PCR data of the microbiota using non‐metric multidimensional scaling (NMS) and blocked multiresponse permutation procedure (MRBP) revealed that the microbiota of the HWG and LWG piglets tended to differ in ileal mucosa (p = .097) and differed in colonic lumen (p = .024). The microbiota of HWG piglets had higher levels of Bacteroidetes, Bacteroides and Ruminoccocaceae, and lower proportions of Actinobacillus porcinus and Lactobacillus amylovorus when compared with those of LWG piglets. As the weight gain of nursing piglets is highly correlated with the amount of ingested colostrum and milk, the results strongly suggest that colostrum and milk intake in the first 2 weeks of life influenced the development of the gut microbiota.     

Moving riparian management guidelines towards a natural disturbance model: An example using boreal riparian and shoreline forest bird communities

Forest harvesting strategies that approximate natural disturbances have been proposed as a means of maintaining natural species’ diversity and richness in the boreal forests of North America. Natural disturbances impact shoreline forests and upland areas at similar rates. However, shoreline forests are generally protected from harvest through the retention of treed buffer strips. We examined bird community responses to forest management guidelines intended to approximate shoreline forest fires by comparing bird community structure in early (1–4 years) post-burned and harvested boreal riparian habitats and the adjacent shoreline forest. We sampled riparian areas with adjacent: (1) burned merchantable shoreline forest (n = 21), (2) burned non-merchantable shoreline forest (n = 29), (3) 10 m treed buffer with 25% retention in the next 30 m (n = 18), and (4) 30 m treed buffer (n = 21). Only minor differences were detected in riparian species’ abundance and bird community composition between treatments with greater differences in these parameters occurring between post-fire and post-harvest upland bird communities. Indicators of all merchantable treatments were dominated by upland species with open-habitat species and habitat generalists being typical upland indicator species of burned merchantable habitats and forest specialists typical upland indicators of harvested treatments. Riparian species indicative of burned riparian habitats were Common Yellowthroat (Geothlypis trichas), Le Conte’s Sparrow (Ammodramus leconteii) and Eastern Kingbird (Tyrannus tyrannus) and indicators of 30 m buffers were Alder Flycatcher (Empidonax alnorum) and Wilson’s Warbler (Wilsonia pusilla). Multivariate Redundancy Analysis (RDA) of the overall (riparian and upland birds) community showed greater divergence than RDA with only riparian species suggesting less effect of fire and forestry on riparian birds than on upland birds. Higher natural range of variability (NRV) of overall post-fire bird communities compared to post-harvest communities emphasizes that harvesting guidelines currently do not achieve this level of variability. However, lack of a large negative effect on common riparian species in the first 4 years post-disturbance allows for the exploration of alternative shoreline forest management that better incorporates bird community composition of post-fire riparian areas and shoreline forests.