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We describe the design and deployment of GREENBURST, a commensal Fast Radio Burst (FRB) search system at the Green Bank Telescope. GREENBURST uses the dedicated L-band receiver tap to search over the 960–1 920 MHz frequency range for pulses with dispersion measures out to
. Due to its unique design, GREENBURST is capable of conducting searches for FRBs when the L-band receiver is not being used for scheduled observing. This makes it a sensitive single pixel detector capable of reaching deeper in the radio sky. While single pulses from Galactic pulsars and rotating radio transients will be detectable in our observations, and will form part of the database we archive, the primary goal is to detect and study FRBs. Based on recent determinations of the all-sky rate, we predict that the system will detect approximately one FRB for every 2–3 months of continuous operation. The high sensitivity of GREENBURST means that it will also be able to probe the slope of the FRB fluence distribution, which is currently uncertain in this observing band.
To determine accessibility of the primary healthcare system for patients with stroke recently discharged from hospital.
This project mapped retrospective patient location data and the location of primary healthcare services in the same region. Patient location data were from all patients with stroke (N = 1595: January 2011–January 2017) discharged from one metropolitan hospital to the local Primary Health Network. Geographic Information System technology was used to map the patient discharge locations and the spatial distribution of primary healthcare services (general practitioner, pharmacy, allied health) across the region. Road network data were used to measure the level of access from each patient’s discharge location to the services.
Access to primary healthcare services was variable. Areas with larger proportions of patients with stroke did not necessarily have good service access. With an increase in travel time, the number of services accessible to patients also increased. However, the spatial variation of access to services remained largely unchanged.
Access to primary healthcare services for patients with stroke varies spatially, with a trend towards relatively low levels of accessibility for many patients. There is an urgent need for future planning to consider geographical access to primary healthcare services for patients with stroke.
A better understanding of the relative importance of factors related to climate change and to changes associated with economic growth would serve to inform water policy and to focus scarce public resources on anticipated problems arising from distinct sources of changes in water demand. This article investigates the determinants of residential water consumption in Chile, a developing country that has seen noteworthy changes in incomes, household size, poverty rates and levels of urbanization, and which is projected to experience significant climatic but varied changes, depending on the region of the country. Panel data for 1998-2010 at the municipal level is used to analyze the sensitivity of residential water demand to climate and development-related factors. In the case of Chile, the effect on water consumption of these development-related changes is estimated to be several times that of the changes associated with climate projections for 50 to 80 years in the future.
In the United States, cannabis accessibility has continued to rise as the perception of its harmfulness has decreased. Only about 30% of regular cannabis users develop cannabis use disorder (CUD), but it is unclear if individuals who use cannabis regularly without ever developing CUD experience notable psychosocial impairment across the lifespan. Therefore, psychosocial functioning was compared across regular cannabis users with or without CUD and a non-user control group during adolescence (age 17; early risk) and young adulthood (ages 18–25; peak CUD prevalence).
Weekly cannabis users with CUD (n = 311), weekly users without CUD (n = 111), and non-users (n = 996) were identified in the Minnesota Twin Family Study. Groups were compared on alcohol and illicit drug use, psychiatric problems, personality, and social functioning at age 17 and from ages 18 to 25. Self-reported cannabis use and problem use were independently verified using co-twin informant report.
In both adolescence and young adulthood, non-CUD users reported significantly higher levels of substance use problems and externalizing behaviors than non-users, but lower levels than CUD users. High agreement between self- and co-twin informant reports confirmed the validity of self-reported cannabis use problems.
Even in the absence of CUD, regular cannabis use was associated with psychosocial impairment in adolescence and young adulthood. However, regular users with CUD endorsed especially high psychiatric comorbidity and psychosocial impairment. The need for early prevention and intervention – regardless of CUD status – was highlighted by the presence of these patterns in adolescence.
The Perth Astronomy Research Group (PARG), consisting of members from Curtin University of Technology, Perth Observatory and the University of Western Australia, is in the process of developing an automated supernova search system, using the 61-cm Lowell-Perth reflector, a CCD camera and an 80386-based computer for image analysis. Computer control of the telescope and dome, a liquid-nitrogen-cooled CCD camera, and modified VISTA image analysis software will be completed in late 1990, allowing initial semi-automatic searching of external galaxies, together with CCD photometry of flare stars and newly discovered supernovae. Full-scale automation will be introduced subsequently, in collaboration with the Berkeley group. This paper describes the project, and reports on its current status.
This essay analyzes the economic conditions associated with urban social disturbances in the United States in the 1960s. Using state-level data on the social disturbances in conjunction with census data from the Integrated Public Use Microdata Series, the analysis tests the relationship between measures of wage inequality and measures of social disorder. In conjunction with accounts of the unrest, the findings support the rising expectations hypothesis, an aspect of the relative deprivation view of racial violence. In particular, overall wage inequality is a significant factor in the disturbances. Also, although the residual or discrimination component of wage inequality and the human capital component are related to the disturbances in the same way, this relationship is stronger for the human capital component of inequality.
To investigate the feasibility and acceptability of using wearable cameras as a method to capture the opportunities for food and drink purchasing/consumption that young people encounter on their regular journeys to and from school.
A qualitative study using multiple data-collection methods including wearable cameras, global positioning system units, individual interviews, food and drink purchase and consumption diaries completed by participants over four days, and an audit of food outlets located within an 800 m Euclidean buffer zone around each school.
A community setting.
Twenty-two students (fourteen girls and eight boys) aged 13–15 years recruited from four secondary schools in two counties of England.
Wearable cameras offered a feasible and acceptable method for collecting food purchase and consumption data when used alongside traditional methods of data collection in a small number of teenagers. We found evidence of participants making deliberate choices about whether or not to purchase/consume food and drink on their journeys. These choices were influenced by priorities over money, friends, journey length, travel mode and ease of access to opportunities for purchase/consumption. Most food and drink items were purchased/consumed within an 800 m Euclidean buffer around school, with items commonly selected being high in energy, fat and sugar. Wearable camera images combined with interviews helped identify unreported items and misreporting errors.
Wearable camera images prompt detailed discussion and generate contextually specific information which could offer new insights and understanding around eating behaviour patterns. The feasibility of scaling up the use of these methods requires further empirical work.
Reactive ion etching of features down to 100 nm in linewidth in tungsten has been studied using an SF6 based chemistry. The studies were carried out in a PlasmaTherm 500 etcher operated at low pressure (2 mTorr) and power (100 mWatts/cm2). Key processing parameters have been identified to achieve the resolution and aspect ratio required for high contrast x-ray masks. The critical parameters include sample temperature, gas dilution and end point detection. However, even with all of these parameters optimized, additional sidewall passivation is required to obtain the necessary 6.5:1 aspect ratio. A novel method of achieving such passivation based on an intermittent etching process is described.
The glyme adducts of bis(1,1,1,5,5,5-hexafluoro-2,4-pentanedionate)barium, Ba(hfac)2•glyme, are frequently employed as precursors in the MOCVD fabrication of HTSC thin films. The physical properties of these precursors can be modified by changing the glyme ligand in the barium complex. In this study, gas phase concentrations of two barium complexes as a function of purge time and bubbler temperature have been examined by in-situ UV spectroscopy. Also presented are the details of a UV spectrophotometric-based feedback control system designed to maintain constant gas phase concentration of 2,2,6,6-tetramethyl-3,5-heptadionate (thd) precursors, Cu(thd)2 and Y(thd)3, during MOCVD growth of mixed metal oxide films.
Deforestation rates in South-East Asia are among the highest of any tropical region, with expansion of oil palm being one important factor. Despite this, few studies have investigated the impact of oil palm expansion on the arthropod fauna. We report here the first study on the impact of forest conversion to oil palm on overall arthropod abundance, biomass and composition. We compared arthropod abundance and biomass, collected from epiphytic bird's nest ferns, the canopy, and leaf litter between primary forest, logged forest and oil palm plantation. Epiphytes, canopy and litter all contained a lower abundance (epiphytes: 67.2%, canopy: 2.3% and litter: 77.1% reduction) and biomass (epiphytes: 87.5%, canopy: 37.9% and litter: 72.4% reduction) of arthropods in oil palm compared with primary forest. However, not all orders of arthropods showed the same level of decline, with some groups having higher abundance and biomass in oil palm, resulting in an altered community composition in the epiphytes and canopy in oil palm compared with forest. Our results show that forest conversion to oil palm impacts detrimentally on invertebrates in all compartments of the forest ecosystem.
Thomas M. Brooks, Center for Applied Biodiversity Science Conservation International, Washington,
Naamal De Silva, ICRAF – The World Agroforestry Centre, PO Box 35024 University of the Philippines, Los Baños, Laguna 4031, Philippines.,
Melizar V. Duya, Conservation International – Philippines 6 Maalalahanin St, Teacher's Village, Diliman, Quezon City, 1101 Philippines.,
Matt Foster, ICRAF – The World Agroforestry Centre University of the Philippines,
David Knox, ICRAF – The World Agroforestry Centre, PO Box 35024 University of the Philippines, Los Baños, Laguna 4031, Philippines.,
Penny Langhammer, ICRAF – The World Agroforestry Centre, PO Box 35024 University of the Philippines, Los Baños, Laguna 4031, Philippines.,
Marthy R. William, Conservation International – Indonesia Jl Pejaten Barat 16 A, Kemang, Jakarta – 12550, Indonesia.,
Blas Tabaranza, Haribon Foundation for the Conservation of Natural Resources, 4th Floor Fil-Garcia Tower, 140 Kalayaan Ave at Mayaman St Diliman, Quezon City, 1101 Philippines.
Biodiversity faces a crisis, with extinction rates approximately three orders of magnitude higher than those typical of the Earth's history (Pimm et al. 1995). This crisis has numerous negative consequences for humanity, including to economies, health, environmental services, and moral and spiritual well-being (Wilson 2002). The biodiversity crisis is particularly serious in Southeast Asia (Sodhi et al. 2004; Sodhi & Brook 2006), where wholesale extinctions are already in the process of unfolding (Brook et al. 2003). Among a large number of causes of these extinctions, the destruction of natural habitats is the most pervasive, affecting ~90% of all threatened species (Baillie et al. 2004). Given this, it is clear that the primary tactic necessary to stem the crisis is to safeguard sites of global biodiversity significance. This has received intergovernmental mandate, with, for example, the 188 parties to the Convention on Biological Diversity agreeing on a Programme of Work on Protected Areas (http://www.biodiv.org/programmes/cross-cutting/protected) to support the establishment and maintenance ‘of comprehensive, effectively managed, and ecologically representative national and regional systems of protected areas’ (Decision VII/28). However, this raises the question of how these sites can best be identified and delineated.
This chapter addresses this question. We begin by explaining the variety of factors that require consideration in the identification of those areas requiring site safeguard. Next, we show how the approach of identifying and delineating Key Biodiversity Areas (KBAs) emerges from these considerations. Finally, we discuss the issue of how KBAs can best be delineated.
Bird's nest ferns (Asplenium nidus complex) (Yatabe & Murakami 2003) are common epiphytes of the Old World tropics and house a high abundance of arthropods (Ellwood & Foster 2004). Through interception and retention of leaf litter (Paoletti et al. 1991, Piggott 1996, Richardson 1999), epiphytes interrupt litterfall dynamics (Clark et al. 1998, Nadkarni & Matelson 1991) and delay the return of nutrients to the forest floor (Nadkarni 1984). Precipitation percolating through the canopy as throughfall is enriched as nutrients are leached from plant surfaces (Levia & Frost 2006). Water flowing down the trunk of trees as stemflow is further enriched from prolonged contact and accumulated nutrient deposits on the trunk (Levia & Frost 2003, Liu et al. 2002). Epiphytes can alter stemflow nutrient concentrations by slowing water percolation and by nutrient uptake and release (Awasthi et al. 1995, Strigel et al. 1994).
The vascular endothelium is a dynamic and metabolically active organ with numerous functions, including regulation of the coagulation cascade and local blood flow, control of fluid passage into the media, and the regulation of cell migration through the vascular intima (1, 2). These many functions are reflected in the variety of molecules expressed at the cell surface and secreted by endothelial cells (ECs). The appearance of such molecules in measurable quantities in the blood allows indirect measurement of the status of the endothelium, which can exist in various different states: resting, activated, and/or dysfunctional. Stimulation of resting endothelium (e.g., by inflammatory cytokines) results in an activation state, characterized by the up regulation of various cell adhesion molecules and procoagulant molecules. Dysfunction can be thought of as an inability of the endothelium to carry out its normal physiological functions (2, 3).
The ideal test of endothelial function would be simple, quick, and inexpensive to perform, sensitive, endothelial specific, correlated with a known disease process, and deranged in a predictable way in disease processes. In other words, it would be a reliable surrogate marker for a specific endothelial disease process. In addition, the marker would be stable enough to measure reliably in the laboratory, yet also have sufficiently rapid turnover or short half-life to provide a meaningful measure of current endothelial status. These criteria effectively remove nitric oxide (NO) from a list of useful markers because it cannot be measured directly or in a simple manner in the laboratory.
Following the introduction of combination antiretroviral therapy, children vertically infected with the human immunodeficiency virus (HIV-1) living in the developed world are surviving into adult life. This paper reviews the neurodevelopmental outcomes of 62 consecutively-presenting children with HIV-1 infection diagnosed before 3 years of age (32 males, 30 females; median age at presentation 6mo). Neurological and developmental data are presented with immunological and virological responses to antiretroviral therapy. Fourteen children (22%) had abnormal neurological signs and 25 (40%) demonstrated significant developmental delay on standardized developmental assessments. Children presenting with more severe HIV-1 disease and immune compromise had significantly more abnormal neurological signs and developmental delays than children presenting with milder HIV-1 symptomatology. Immune function, control of HIV-1 viral replication, and growth parameters improved with antiretroviral therapy (median age at last follow-up 7y 3mo); however, abnormal neurological signs and significant gross motor difficulties persisted.
Spatial surveys of marine benthic habitats and biota based on the interpretation of acoustic data were carried out at two sites in the eastern English Channel each representing different scales of geographic area and intensity of survey. A small area (4×12 km) crossing the Hastings Shingle Bank was surveyed at a relatively high intensity (track spacing 400 m) and was nested within a larger area between Hastings and Dungeness (12×40 km), which was surveyed at a lower intensity (track spacing 2 km). Surveys were conducted with two acoustic ground discrimination systems (AGDS), RoxAnn and QTC-VIEW and the primary purpose of the investigation was to compare the performance of the two AGDS using a common approach to analysis of the different data outputs (E1 and E2 for RoxAnn and the Q eigenvectors from QTC-VIEW). Exploratory data analysis using variography indicated that interpolation between tracks was justified for the smaller site to create a complete coverage, but was limited to the creation of a digital image of the track data for the larger area. Grab and video sample data were available for supervised classification of the AGDS data and interpreted sidescan images for comparison with unsupervised classification. Both AGDS gave similar outputs, although RoxAnn consistently gave slightly better levels of performance than QTC-VIEW as measured using error matrices. Although the investigation was not designed to compare the performance of AGDS and sidescan, the outputs from AGDS were similar to the visual interpretation of the sidescan sonar data. It was concluded that despite the inherent limitations of AGDS, they may be suitable for providing distribution maps at a broad scale that can give a context for the interpretation of finer scale survey of smaller, nested areas.