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In the original publication of this article, the title was printed as “Four Preceramic Points Newly Discovered in Belize: A Comment on Stemp et al. (1996:279–299).” The article has been updated to the correct title. The authors apologize for this error.
The discovery of the first electromagnetic counterpart to a gravitational wave signal has generated follow-up observations by over 50 facilities world-wide, ushering in the new era of multi-messenger astronomy. In this paper, we present follow-up observations of the gravitational wave event GW170817 and its electromagnetic counterpart SSS17a/DLT17ck (IAU label AT2017gfo) by 14 Australian telescopes and partner observatories as part of Australian-based and Australian-led research programs. We report early- to late-time multi-wavelength observations, including optical imaging and spectroscopy, mid-infrared imaging, radio imaging, and searches for fast radio bursts. Our optical spectra reveal that the transient source emission cooled from approximately 6 400 K to 2 100 K over a 7-d period and produced no significant optical emission lines. The spectral profiles, cooling rate, and photometric light curves are consistent with the expected outburst and subsequent processes of a binary neutron star merger. Star formation in the host galaxy probably ceased at least a Gyr ago, although there is evidence for a galaxy merger. Binary pulsars with short (100 Myr) decay times are therefore unlikely progenitors, but pulsars like PSR B1534+12 with its 2.7 Gyr coalescence time could produce such a merger. The displacement (~2.2 kpc) of the binary star system from the centre of the main galaxy is not unusual for stars in the host galaxy or stars originating in the merging galaxy, and therefore any constraints on the kick velocity imparted to the progenitor are poor.
Stemp et al. (2016) published data on 81 preceramic (Archaic) points from Belize, Central America. In this comment, we report four more chipped chert bifaces recently recovered in Belize (Figure 1). Based on metrics (Table 1), technology, and style, three are classified as Lowe and one as a Sawmill point (Kelly 1993; Lohse et al. 2006; Stemp et al. 2016).
Radiocarbon dating using charcoal and bone collagen, two standards of archaeological chronology, can be difficult to impossible in environments where natural burning is common and bone does not preserve well. In such settings, charcoal ages cannot always be trusted and collagen is unavailable. Calcined bone can be a viable alternative medium in these situations but it has rarely been exploited in the Americas. One area that could benefit from its use is the forested Pacific Northwest. We compare calcined bone ages with charcoal and/or collagen dates from individual features or discrete cultural strata in 10 Washington, Oregon, Idaho, and British Columbia sites dating between 9000 and 100 B.P. Resulting radiocarbon age estimates based on calcined bone closely match those based on charcoal and/or collagen in nearly all cases. We obtained calcined bone dates from three additional Holocene-aged sites that had not previously produced accurate results, obtaining findings consistent with estimates based on cross dating. Preserving well where all other organic media of cultural origin are lost or unreliable, calcined bone holds promise for dating sites in conifer forests and other acidic soil settings, and can allow researchers to refine archaeological sequences that have long defied accurate chronometric analysis.
The Numeniini is a tribe of 13 wader species (Scolopacidae, Charadriiformes) of which seven are Near Threatened or globally threatened, including two Critically Endangered. To help inform conservation management and policy responses, we present the results of an expert assessment of the threats that members of this taxonomic group face across migratory flyways. Most threats are increasing in intensity, particularly in non-breeding areas, where habitat loss resulting from residential and commercial development, aquaculture, mining, transport, disturbance, problematic invasive species, pollution and climate change were regarded as having the greatest detrimental impact. Fewer threats (mining, disturbance, problematic native species and climate change) were identified as widely affecting breeding areas. Numeniini populations face the greatest number of non-breeding threats in the East Asian-Australasian Flyway, especially those associated with coastal reclamation; related threats were also identified across the Central and Atlantic Americas, and East Atlantic flyways. Threats on the breeding grounds were greatest in Central and Atlantic Americas, East Atlantic and West Asian flyways. Three priority actions were associated with monitoring and research: to monitor breeding population trends (which for species breeding in remote areas may best be achieved through surveys at key non-breeding sites), to deploy tracking technologies to identify migratory connectivity, and to monitor land-cover change across breeding and non-breeding areas. Two priority actions were focused on conservation and policy responses: to identify and effectively protect key non-breeding sites across all flyways (particularly in the East Asian- Australasian Flyway), and to implement successful conservation interventions at a sufficient scale across human-dominated landscapes for species’ recovery to be achieved. If implemented urgently, these measures in combination have the potential to alter the current population declines of many Numeniini species and provide a template for the conservation of other groups of threatened species.
New paediatric cardiology trainees are required to rapidly assimilate knowledge and gain clinical skills to which they have limited or no exposure during residency. The Pediatric Cardiology Fellowship Boot Camp (PCBC) at Boston Children’s Hospital was designed to provide incoming fellows with an intensive exposure to congenital cardiac pathology and a broad overview of major areas of paediatric cardiology practice.
The PCBC curriculum was designed by core faculty in cardiac pathology, echocardiography, electrophysiology, interventional cardiology, exercise physiology, and cardiac intensive care. Individual faculty contributed learning objectives, which were refined by fellowship directors and used to build a programme of didactics, hands-on/simulation-based activities, and self-guided learning opportunities.
A total of 16 incoming fellows participated in the 4-week boot camp, with no concurrent clinical responsibilities, over 2 years. On the basis of pre- and post-PCBC surveys, 80% of trainees strongly agreed that they felt more prepared for clinical responsibilities, and a similar percentage felt that PCBC should be offered to future incoming fellows. Fellows showed significant increase in their confidence in all specific knowledge and skills related to the learning objectives. Fellows rated hands-on learning experiences and simulation-based exercises most highly.
We describe a novel 4-week-long boot camp designed to expose incoming paediatric cardiology fellows to the broad spectrum of knowledge and skills required for the practice of paediatric cardiology. The experience increased trainee confidence and sense of preparedness to begin fellowship-related responsibilities. Given that highly interactive activities were rated most highly, boot camps in paediatric cardiology should strongly emphasise these elements.
This paper analyzes in detail the role of environmental and economic shocks in the migration of the 1930s. The 1940 US Census of Population asked every inhabitant where they lived five years earlier, a unique source for understanding migration flows and networks. Earlier research documented migrant origins and destinations, but we will show how short-term and annual weather conditions at sending locations in the 1930s explain those flows, and how they operated through agricultural success. Beyond demographic data, we use data about temperature and precipitation, plus data about agricultural production from the agricultural census. The widely known migration literature for the 1930s describes an era of relatively low migration, with much of the migration that did occur radiating outward from the Dust Bowl region and the cotton South. Our work about the complete United States will provide a fuller examination of migration in this socially and economically important era.
The Dark Energy Survey is undertaking an observational programme imaging 1/4 of the southern hemisphere sky with unprecedented photometric accuracy. In the process of observing millions of faint stars and galaxies to constrain the parameters of the dark energy equation of state, the Dark Energy Survey will obtain pre-discovery images of the regions surrounding an estimated 100 gamma-ray bursts over 5 yr. Once gamma-ray bursts are detected by, e.g., the Swift satellite, the DES data will be extremely useful for follow-up observations by the transient astronomy community. We describe a recently-commissioned suite of software that listens continuously for automated notices of gamma-ray burst activity, collates information from archival DES data, and disseminates relevant data products back to the community in near-real-time. Of particular importance are the opportunities that non-public DES data provide for relative photometry of the optical counterparts of gamma-ray bursts, as well as for identifying key characteristics (e.g., photometric redshifts) of potential gamma-ray burst host galaxies. We provide the functional details of the DESAlert software, and its data products, and we show sample results from the application of DESAlert to numerous previously detected gamma-ray bursts, including the possible identification of several heretofore unknown gamma-ray burst hosts.
Healthcare provider hands are an important source of intraoperative bacterial transmission events associated with postoperative infection development.
To explore the efficacy of a novel hand hygiene improvement system leveraging provider proximity and individual and group performance feedback in reducing 30-day postoperative healthcare-associated infections via increased provider hourly hand decontamination events.
Randomized, prospective study.
Dartmouth-Hitchcock Medical Center in New Hampshire and UMass Memorial Medical Center in Massachusetts.
Patients undergoing surgery.
Operating room environments were randomly assigned to usual intraoperative hand hygiene or to a personalized, body-worn hand hygiene system. Anesthesia and circulating nurse provider hourly hand decontamination events were continuously monitored and reported. All patients were followed prospectively for the development of 30-day postoperative healthcare-associated infections.
A total of 3,256 operating room environments and patients (1,620 control and 1,636 treatment) were enrolled. The mean (SD) provider hand decontamination event rate achieved was 4.3 (2.9) events per hour, an approximate 8-fold increase in hand decontamination events above that of conventional wall-mounted devices (0.57 events/hour); P<.001. Use of the hand hygiene system was not associated with a reduction in healthcare-associated infections (odds ratio, 1.07 [95% CI, 0.82–1.40], P=.626).
The hand hygiene system evaluated in this study increased the frequency of hand decontamination events without reducing 30-day postoperative healthcare-associated infections. Future work is indicated to optimize the efficacy of this hand hygiene improvement strategy.
HIV prevalence in China is less than one per cent, but the absolute number of people living with HIV/AIDS is large and growing. Given the limited scope of any potential cure for HIV, prevention plays a crucial role in controlling the epidemic. This paper examines the evolution of HIV awareness among women in China between 1997 and 2005. A regression decomposition analysis technique was used to disentangle the two main components driving a change in HIV awareness. The results show that HIV awareness has increased over time in China. The gaps between groups are narrowing over time and lower HIV awareness groups are catching up with the higher awareness groups. In 2005 education remained one of the main factors associated with HIV awareness, the other main factors being ethnicity, exposure to TV and newspapers. The increases in HIV awareness observed between 1997 and 2001 are similar between groups of women with different demographic characteristics, whereas between 2003 and 2005 increases are more pronounced among specific groups of women such as women from rural areas, women from Western parts of the country, women who belong to ethnic minorities and those with no education or with only primary education. The results suggest that the main driver of the observed change in HIV awareness over time in China is change in the environment such as in political commitment, interventions and campaigns rather than change in population structure.
The advent of aberration correction for transmission electron microscopy has transformed atomic resolution imaging into a nearly routine technique for structural analysis. Now an emerging frontier in electron microscopy is the development of in situ capabilities to observe reactions at atomic resolution in real time and within realistic environments. Here we present a new in situ gas cell holder that is designed for compatibility with a wide variety of sample type (i.e., dimpled 3-mm discs, standard mesh grids, various types of focused ion beam lamellae attached to half grids). Its capabilities include localized heating and precise control of the gas pressure and composition while simultaneously allowing atomic resolution imaging at ambient pressure. The results show that 0.25-nm lattice fringes are directly visible for nanoparticles imaged at ambient pressure with gas path lengths up to 20 μm. Additionally, we quantitatively demonstrate that while the attainable contrast and resolution decrease with increasing pressure and gas path length, resolutions better than 0.2 nm should be accessible at ambient pressure with gas path lengths less than the 15 μm utilized for these experiments.