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The Rapid ASKAP Continuum Survey (RACS) is the first large-area survey to be conducted with the full 36-antenna Australian Square Kilometre Array Pathfinder (ASKAP) telescope. RACS will provide a shallow model of the ASKAP sky that will aid the calibration of future deep ASKAP surveys. RACS will cover the whole sky visible from the ASKAP site in Western Australia and will cover the full ASKAP band of 700–1800 MHz. The RACS images are generally deeper than the existing NRAO VLA Sky Survey and Sydney University Molonglo Sky Survey radio surveys and have better spatial resolution. All RACS survey products will be public, including radio images (with
15 arcsec resolution) and catalogues of about three million source components with spectral index and polarisation information. In this paper, we present a description of the RACS survey and the first data release of 903 images covering the sky south of declination
made over a 288-MHz band centred at 887.5 MHz.
Breakthrough Listen is a 10-yr initiative to search for signatures of technologies created by extraterrestrial civilisations at radio and optical wavelengths. Here, we detail the digital data recording system deployed for Breakthrough Listen observations at the 64-m aperture CSIRO Parkes Telescope in New South Wales, Australia. The recording system currently implements two modes: a dual-polarisation, 1.125-GHz bandwidth mode for single-beam observations, and a 26-input, 308-MHz bandwidth mode for the 21-cm multibeam receiver. The system is also designed to support a 3-GHz single-beam mode for the forthcoming Parkes ultra-wideband feed. In this paper, we present details of the system architecture, provide an overview of hardware and software, and present initial performance results.
Credibility and trustworthiness are the bedrock upon which any science is built. The strength of these foundations has been increasingly questioned across the sciences as instances of research misconduct and mounting concerns over the prevalence of detrimental research practices have been identified. Consequently, the purpose of this article is to encourage our scientific community to positively and proactively engage in efforts that foster a healthy and robust industrial and organizational (I-O) psychology. We begin by advancing six defining principles that we believe reflect the values of robust science and offer criteria for evaluating proposed efforts to change scientific practices. Recognizing that the contemporary scientific enterprise is a complex and diverse network of actors and institutions, we then conclude by identifying 12 stakeholders who play important roles in achieving a culture of robust science in I-O psychology and offer recommendations for actions we can take as members of these groups to strengthen our science.
Human mesenchymal stem cells (MSCs) are the most intensely studied and clinically used adult stem cell type. Conventional long-term cultivation of MSCs as a monolayer is known to result in a reduction of their functionality and viability. In addition, large volumes of cell culture medium are required to obtain cell quantities needed for their clinical use. In this proof of concept study, we cultivated human MSCs within a three-dimensional nanofibrillar cellulose (NFC) hydrogel. We show that NFC is biocompatible with human MSCs, and represents a feasible approach to upscaling of their culture.
Although participating in community social programming is associated with positive physical and mental health outcomes for older adults, older men participate less often than women. Men's Sheds is a community programme used primarily by older men that originated in Australia and is well established there. The goal of the current study was to explore men's perceptions of the need for Men's Sheds and issues concerning access to them in Canada, a country with a small but growing Men's Sheds movement. We conducted focus groups with 64 men aged 55 years and older, including Men's Sheds members and men from the community who were unfamiliar with this programme, and analysed the data using the framework analytic approach. The data revealed two primary themes concerning: (a) the need for male-focused community programmes, including the sub-themes reducing isolation, forming friendships and engaging in continued learning; and (b) access to programmes, including the sub-themes points of contact, sustaining attendance and barriers. Findings suggest that in order to reduce the likelihood of isolation and increase opportunities for social engagement, exposure to the concept of male-focused programming should begin before retirement age. In addition, such programmes should be mindful of how they are branded and marketed in order to create spaces that are welcoming to new and diverse members.
Geologic archives show that the Earth was dustier during the last glacial period. One model suggests that increased gustiness (stronger, more frequent winds) enhanced dustiness. We tested this at Loveland, Iowa, one of the thickest deposits of last-glacial-age (Peoria) loess in the world. Based on K/Rb and Ba/Rb, loess was derived not only from glaciogenic sources of the Missouri River, but also distal loess from non-glacial sources in Nebraska. Optically stimulated luminescence (OSL) ages provide the first detailed chronology of Peoria Loess at Loveland. Deposition began after ~ 27 ka and continued until ~ 17 ka. OSL ages also indicate that mass accumulation rates (MARs) of loess were not constant. MARs were highest and grain size was coarsest during the time of middle Peoria Loess accretion, ~ 23 ka, when ~ 10 m of loess accumulated in no more than ~ 2000 yr and possibly much less. The timing of coarsest grain size and highest MAR, indicating strongest winds, coincides with a summer-insolation minimum at high latitudes in North America and the maximum southward extent of the Laurentide ice sheet. These observations suggest that increased dustiness during the last glacial period was driven largely by enhanced gustiness, forced by a steepened meridional temperature gradient.
The Australian Square Kilometre Array Pathfinder (ASKAP) will give us an unprecedented opportunity to investigate the transient sky at radio wavelengths. In this paper we present VAST, an ASKAP survey for Variables and Slow Transients. VAST will exploit the wide-field survey capabilities of ASKAP to enable the discovery and investigation of variable and transient phenomena from the local to the cosmological, including flare stars, intermittent pulsars, X-ray binaries, magnetars, extreme scattering events, interstellar scintillation, radio supernovae, and orphan afterglows of gamma-ray bursts. In addition, it will allow us to probe unexplored regions of parameter space where new classes of transient sources may be detected. In this paper we review the known radio transient and variable populations and the current results from blind radio surveys. We outline a comprehensive program based on a multi-tiered survey strategy to characterise the radio transient sky through detection and monitoring of transient and variable sources on the ASKAP imaging timescales of 5 s and greater. We also present an analysis of the expected source populations that we will be able to detect with VAST.
The 2005 articles by Stoltman et al. and Flannery et al. to which Neff et al. (this issue) have responded are not an indictment of instrumental neutron activation analysis (INAA) but, rather, of the way Blomster et al. (2005) misuse it and of the hyperbolic culture-historical claims they have made from their INAA results. It has long been acknowledged that INAA leads not to sources but to chemical composition groups. Based on composition groups derived from an extremely unsystematic collection of sherds from only seven localities, Blomster et al. claim that the Olmec received no carved gray or kaolin white pottery from other regions; they also claim that neighboring valleys in the Mexican highlands did not exchange such pottery with each other. Not only can one not leap directly from the elements in potsherds to such sweeping culture-historical conclusions, it is also the case that other lines of evidence (including petrographic analysis) have for 40+ years produced empirical evidence to the contrary. In the end, it was their commitment to an unfalsifiable model of Olmec superiority that led Blomster et al. to bypass the logic of archaeological inference.
Recent studies have revealed that calcium limitation of avian reproduction may be a widespread phenomenon, affecting both egg properties and chick development. The effect of calcium shortage on the final body size of fledglings is usually rather weak, possibly owing to compensatory growth. Achieving full skeletal size is not, however, a reliable indication of complete ossification and it is possible that chicks with similar tarsus lengths are in different stages of skeletal development. We hypothesized that measuring plasma activity of the bone alkaline phosphatase (ALP), a highly specific marker for bone calcification, may reveal subtle developmental differences in full-grown fledglings, having experienced different levels of calcium availability during growth. In two seasons, a number of pairs of great tit Parus major were provided with calcium-rich material during the nestling period, while others were not supplemented (controls). While no significant differences in size of fledglings were detected between groups, bone-ALP activity at the pre-fledging stage was lower in the calcium-provided nestlings than in the control nestlings. This may indicate that supplemented chicks had completed the rapid phase of bone formation, but this process was delayed in controls. Measuring ALP as a marker of skeletal development expands our knowledge of how delayed skeletal development of chicks can result in protraction of the nestling period, thereby reducing the breeding success of adult birds.
In the nearly 80 years since Skutch (1935) coined the term “helper-at-the-nest,” cooperative breeding has attracted considerable interest, to no small extent because helping to raise non-descendant young violates a primary tenet of Darwinian theory. This “paradox” of how cooperative breeding could have evolved and subsequently have been maintained was partially resolved first by Hamilton (1963), who introduced the concept of kin-selected benefits by individuals that assist in rearing related individuals other than their own offspring, and later by Brown (1978), Koenig and Pitelka (1981), and Emlen (1982a), who developed the hypothesis that cooperatively breeding species were constrained by specific habitat requirements that induced philopatry, thus setting the stage for helping behavior.
Here we focus on the contributions of field endocrinology to our proximate-level understanding of cooperative breeding. Given that hormones are involved in mediating virtually all aspects of an organism's life and affect functions as diverse as gut absorption, blood production, and reproductive and agonistic behaviors, we can expect that they will also play an important role in the various kinds of cooperative and competitive interactions characteristic of cooperative breeders.
Two endocrine axes are of primary interest here: the hypothalamo-pituitary-gonadal (HPG) axis and the hypothalamo–pituitary–adrenal (HPA) axis. The HPG axis consists of a region of the forebrain known as the hypothalamus, the pituitary that lies immediately below, and the gonads (Fig. 8.1). In response to stimulatory environmental or endogenous cues, the hypothalamus secretes gonadotropin-releasing hormone (GnRH).
Food availability is one of the most important determinants of successful reproduction in birds. In a previous study, it was shown that Florida scrub-jays Aphelocoma coerulescens maintained a third egg mass when supplemented with a high fat and high protein diet during pre-breeding, as opposed to birds that were not supplemented that laid third eggs markedly lighter in mass than first- and second-laid eggs. Increases in egg quality promote chick growth and survival in many avian species. In this study, scrub-jays were provided with supplements throughout the pre-laying and nestling periods of 2001 and 2002 to investigate whether diet quality influenced growth and survival of chicks. Fledging success and survival to independence of unsupplemented chicks were higher for 2002 compared with 2001 indicating that breeding conditions (e.g. natural food availability) for jays were probably improved in the former year. Consistent growth patterns were found during the first 11 days post-hatch between chicks on supplemented and those on unsupplemented territories. Of the three growth measures, only seventh primary feather growth tended to be greater for third-hatched chicks on supplemented territories compared with third-hatched chicks on control territories. Food supplementation influenced survival of chicks. Compared with chicks hatching on unsupplemented territories, fledging success of chicks hatching from second-laid eggs was significantly greater in 2001, but not in 2002. Chicks from third-laid eggs on supplemented territories also tended to survive better in 2001 compared with chicks from unsupplemented territories, but, again, no such effect was found in 2002. We conclude that food supplementation in the pre-laying and nestling periods results in little measurable improvement in chick growth. However, improvements were found in survival of chicks that may be mediated through improvements in egg quality, but also may be the result of changes in foraging strategies of provisioning birds on supplemented territories. Chicks on supplemented territories might be in better body condition than those on unsupplemented ones. Methods other than morphometrics may be required to detect elevations in body condition of chicks raised on supplemented territories.
Field-studies were conducted over two years to determine the area of influence and duration of interference of wild poinsettia in soybean. Soybean canopy width averaged across years was reduced approximately 10% beginning at 6 wk of interference for both the 0- to 10-and 10-to 20-cm distances from the weed. Soybean dry weights decreased from 14 to 38% within 20 cm of the weed for 12 through 18 wk of interference. In 1990, soybean yield within 10 cm of wild poinsettia was similar to distances of 10 to 20 and 20 to 40 cm, but was less than that for distances greater than 40 cm from the weed. Weed interference resulted in a 9.5% yield reduction in the 0- to 10-cm distance when compared with the 80-to 100-cm distance. In contrast, yield of soybean in 1991 growing within 10 cm of the weed was less than at greater distances, corresponding to an 18% yield reduction when compared with 80 to 100 cm. Differences in wild poinsettia dry weights when growing alone and when growing within the soybean row occurred after 6 and 8 wk of interference in 1990 and 1991, respectively. In 1991 when rainfall during the growing season was twice that of the previous year, canopy width and dry weight of wild poinsettia growing within the soybean row were reduced an average of 57 and 82%, respectively, compared with weeds growing alone.
Limited Reaction Processing (LRP) is a new technique which combines Rapid Thermal Processing (RTP) and Chemical Vapor Deposition (CVD). The added temperature control provided in rapid thermal processing enables the use of substrate temperature as a reaction switch. In addition, rapid thermal technology has been shown to provide other advantages for chemical vapor deposition of Si and III–V materials. Results are presented for group IV materials including epitaxial Si, SiGe alloys, SiO2 , and polysilicon. MOSFETs have been demonstrated and sensitive tests of interface quality are presented, paving the way for future bipolar transistor fabrication. III–V materials such as GaAs, AlGaAs, InGaAs have been grown. GaAs electron mobilities are the best reported for material grown using trimethylarsenic. As-ambient rapid thermal anneals of GaAs have also been performed.
Limited reaction processing (LRP), a new technique which provides precise control of thermally driven surface reactions, was used to grow multilayer structures composed of semiconductors and insulators. Results are presented for group IV-based materials including epitaxial Si, SiGe alloys, SiO2, and polysilicon. III–V materials such as GaAs, AlGaAs, and InGaAs have also been successfully grown. A number of diagnostic techniques were used to define the advantages and capabilities of LRP, including TEM, SIMS and AES. In addition, some preliminary device results are presented.
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