To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure firstname.lastname@example.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Forty years ago, Knut Fladmark (1979) argued that the Pacific Coast offered a viable alternative to the ice-free corridor model for the initial peopling of the Americas—one of the first to support a “coastal migration theory” that remained marginal for decades. Today, the pre-Clovis occupation at the Monte Verde site is widely accepted, several other pre-Clovis sites are well documented, investigations of terminal Pleistocene subaerial and submerged Pacific Coast landscapes have increased, and multiple lines of evidence are helping decode the nature of early human dispersals into the Americas. Misconceptions remain, however, about the state of knowledge, productivity, and deglaciation chronology of Pleistocene coastlines and possible technological connections around the Pacific Rim. We review current evidence for several significant clusters of early Pacific Coast archaeological sites in North and South America that include sites as old or older than Clovis. We argue that stemmed points, foliate points, and crescents (lunates) found around the Pacific Rim may corroborate genomic studies that support an early Pacific Coast dispersal route into the Americas. Still, much remains to be learned about the Pleistocene colonization of the Americas, and multiple working hypotheses are warranted.
Background: Focal cortical dysplasias (FCDs) are congenital structural abnormalities of the brain, and represent the most common cause of medication-resistant focal epilepsy in children and adults. Recent studies have shown that somatic mutations (i.e. mutations arising in the embryo) in mTOR pathway genes underlie some FCD cases. Specific therapies targeting the mTOR pathway are available. However, testing for somatic mTOR pathway mutations in FCD tissue is not performed on a clinical basis, and the contribution of such mutations to the pathogenesis of FCD remains unknown. Aim: To investigate the feasibility of screening for somatic mutations in resected FCD tissue and determine the proportion and spatial distribution of FCDs which are due to low-level somatic mTOR pathway mutations. Methods: We performed ultra-deep sequencing of 13 mTOR pathway genes using a custom HaloPlexHS target enrichment kit (Agilent Technologies) in 16 resected histologically-confirmed FCD specimens. Results: We identified causal variants in 62.5% (10/16) of patients at an alternate allele frequency of 0.75–33.7%. The spatial mutation frequency correlated with the FCD lesion’s size and severity. Conclusions: Screening FCD tissue using a custom panel results in a high yield, and should be considered clinically given the important potential implications regarding surgical resection, medical management and genetic counselling.
We assessed whether paternal demographic, anthropometric and clinical factors influence the risk of an infant being born large-for-gestational-age (LGA). We examined the data on 3659 fathers of term offspring (including 662 LGA infants) born to primiparous women from Screening for Pregnancy Endpoints (SCOPE). LGA was defined as birth weight >90th centile as per INTERGROWTH 21st standards, with reference group being infants ⩽90th centile. Associations between paternal factors and likelihood of an LGA infant were examined using univariable and multivariable models. Men who fathered LGA babies were 180 g heavier at birth (P<0.001) and were more likely to have been born macrosomic (P<0.001) than those whose infants were not LGA. Fathers of LGA infants were 2.1 cm taller (P<0.001), 2.8 kg heavier (P<0.001) and had similar body mass index (BMI). In multivariable models, increasing paternal birth weight and height were independently associated with greater odds of having an LGA infant, irrespective of maternal factors. One unit increase in paternal BMI was associated with 2.9% greater odds of having an LGA boy but not girl; however, this association disappeared after adjustment for maternal BMI. There were no associations between paternal demographic factors or clinical history and infant LGA. In conclusion, fathers who were heavier at birth and were taller were more likely to have an LGA infant, but maternal BMI had a dominant influence on LGA.
The Joint Commission Centre for Transforming Healthcare's Web-based Targeted Solutions Tool (TST) for improving hand hygiene was implemented to elucidate contributing factors to low compliance rates of hand hygiene. Monitoring of compliance was done by trained unknown and known observers and rates of hospital-acquired infections were tracked and correlated against the changes in hand hygiene compliance. In total, 5669 of hand hygiene observations were recorded by the secret observers. The compliance rate increased from 75·4% at baseline (May–August 2014) to 88·6% during the intervention (13 months) and the control periods (P < 0·0001). Reductions in healthcare-associated infection rates were recorded for Clostridium difficle infections from 7·95 (CI 0·8937–28·72) to 1·84 (CI 0·02411–10·26) infections per 10 000 patient-days (P = 0·23), central line-associated blood-stream infections from 5·9 (CI 1·194–17·36) to 2·9 (0·7856–7·475) per 1000 device days (P = 0·37) and catheter-associated urinary tract infections from 5·941 (CI 1·194–17·36) to 0 per 1000 device days (P = 0·42). The top contributing factors for non-compliance were: improper use of gloves, hands full of supplies or medications and frequent entry or exit in isolation areas. We conclude that the application of TST allows healthcare organisations to improve hand hygiene compliance and to identify the factors contributing to non-compliance.
For the last four years we have been engaged on a program to look for intrinsic variations in the Microwave Background Radiation (MBR) at the Owens Valley Radio Observatory (OVRO). We summarize here the results of this continuing search.
We report here an example of a series of computer simulations of the formation of disk galaxies, including a standard cold dark matter component, gas, and star formation, which result in objects which closely resemble observed giant galaxies, with a population of long-lived dwarf satellites which contain little or no non–baryonic dark matter.
Ammonia was searched in the direction of 46 sources placed in the southern hemisphere where H2CO or H2O was detected previously. Observations were carried out at Itapetinga Radio Observatory, Atibaia, Brazil using a 13.7 m paraboloid. The receiver used for these observations had a K-band ruby travelling wave maser as a preamplifier and the system temperature ranged from 250 to 300K. All sources were observed at least twice, each observation lasting for 30 minutes. The filter bank used consisted of 47 contiguous channels with 100 kHz bandwidth. Results are presented on Table 1 — Positive results and Table 2 — Negative results.
We have monitored the 610 MHz flux density of 21 pulsars on a daily basis for five years. The flux density time series for these pulsars range from nearly constant for the most distant and heavily scattered pulsars to rapidly varying, saturated time series for more nearby pulsars. The measured stability of the flux density from the most distant pulsars (variations less than 5%) implies that the average radio emission from pulsars, before it has been affected by propagation through the ISM, is constant in strength over five years. The flux variations for 12 of the pulsars are consistent with a Kolmogorov turbulence spectrum over a range of more than three orders of magnitude in scattering strength, with no detectable presence of an inner scale (si ≥ 107cm). The flux variations are greater than predicted by this model for five pulsars – including the Crab and Vela – but this group is consistent with a Kolmogorov spectrum and an inner scale of ∼ 1010cm.
The ratio of ground-state densities Ro ≡ N (13CO) / N (C18O) has been used to infer physical and chemical conditions in giant molecular clouds (Wannier et al. 1976) and dark clouds (Mahoney et al. 1976; Langer et al. 1979). In dark clouds Ro is found to vary from values near the terrestrial ratio [13C] [16O] / [12C] [18O] ∼ 5 at positions of high extinction to values ∼20 at positions of low extinction. In this paper we present high-resolution J = 1 → 0 spectra of CO, 13CO, and C18O at positions of high extinction in TMC-2, L134, and L134N. The C18O lines have non-Gaussian wings and are ∼ half as wide as the 13CO lines. We find that RO must vary across the line, from a minimum of R0 ∼ 4 at the peak of the C18O line to a maximum of RO ∼ 10 in the wings, unless the 13CO line has peak opacity ∼5. The variation of RO with position and with velocity is consistent with models of clouds which have a dense core with low velocity-dispersion and low fractionation, and a rarefied envelope with high velocity-dispersion and high fractionation.
There is limited evidence on the acceptability, feasibility and cost-effectiveness of task-sharing interventions to narrow the treatment gap for mental disorders in sub-Saharan Africa. The purpose of this article is to describe the rationale, aims and methods of the Africa Focus on Intervention Research for Mental health (AFFIRM) collaborative research hub. AFFIRM is investigating strategies for narrowing the treatment gap for mental disorders in sub-Saharan Africa in four areas. First, it is assessing the feasibility, acceptability and cost-effectiveness of task-sharing interventions by conducting randomised controlled trials in Ethiopia and South Africa. The AFFIRM Task-sharing for the Care of Severe mental disorders (TaSCS) trial in Ethiopia aims to determine the acceptability, affordability, effectiveness and sustainability of mental health care for people with severe mental disorder delivered by trained and supervised non-specialist, primary health care workers compared with an existing psychiatric nurse-led service. The AFFIRM trial in South Africa aims to determine the cost-effectiveness of a task-sharing counselling intervention for maternal depression, delivered by non-specialist community health workers, and to examine factors influencing the implementation of the intervention and future scale up. Second, AFFIRM is building individual and institutional capacity for intervention research in sub-Saharan Africa by providing fellowship and mentorship programmes for candidates in Ethiopia, Ghana, Malawi, Uganda and Zimbabwe. Each year five Fellowships are awarded (one to each country) to attend the MPhil in Public Mental Health, a joint postgraduate programme at the University of Cape Town and Stellenbosch University. AFFIRM also offers short courses in intervention research, and supports PhD students attached to the trials in Ethiopia and South Africa. Third, AFFIRM is collaborating with other regional National Institute of Mental Health funded hubs in Latin America, sub-Saharan Africa and south Asia, by designing and executing shared research projects related to task-sharing and narrowing the treatment gap. Finally, it is establishing a network of collaboration between researchers, non-governmental organisations and government agencies that facilitates the translation of research knowledge into policy and practice. This article describes the developmental process of this multi-site approach, and provides a narrative of challenges and opportunities that have arisen during the early phases. Crucial to the long-term sustainability of this work is the nurturing and sustaining of partnerships between African mental health researchers, policy makers, practitioners and international collaborators.
The number of pediatric antimicrobial stewardship programs (ASPs) is increasing and program evaluation is a key component to improve efficiency and enhance stewardship strategies.
To determine the antimicrobials and diagnoses most strongly associated with a recommendation provided by a well-established pediatric ASP.
DESIGN AND SETTING
Retrospective cohort study from March 3, 2008, to March 2, 2013, of all ASP reviews performed at a free-standing pediatric hospital.
ASP recommendations were classified as follows: stop therapy, modify therapy, optimize therapy, or consult infectious diseases. A multinomial distribution model to determine the probability of each ASP recommendation category was performed on the basis of the specific antimicrobial agent or disease category. A logistic model was used to determine the odds of recommendation disagreement by the prescribing clinician.
The ASP made 2,317 recommendations: stop therapy (45%), modify therapy (26%), optimize therapy (19%), or consult infectious diseases (10%). Third-generation cephalosporins (0.20) were the antimicrobials with the highest predictive probability of an ASP recommendation whereas linezolid (0.05) had the lowest probability. Community-acquired pneumonia (0.26) was the diagnosis with the highest predictive probability of an ASP recommendation whereas fever/neutropenia (0.04) had the lowest probability. Disagreement with ASP recommendations by the prescribing clinician occurred 22% of the time, most commonly involving community-acquired pneumonia and ear/nose/throat infections.
Evaluation of our pediatric ASP identified specific clinical diagnoses and antimicrobials associated with an increased likelihood of an ASP recommendation. Focused interventions targeting these high-yield areas may result in increased program efficiency and efficacy.
Sea-level rise during the late Pleistocene and early Holocene inundated nearshore areas in many parts of the world, producing drastic changes in local ecosystems and obscuring significant portions of the archeological record. Although global forces are at play, the effects of sea-level rise are highly localized due to variability in glacial isostatic adjustment (GIA) effects. Interpretations of coastal paleoecology and archeology require reliable estimates of ancient shorelines that account for GIA effects. Here we build on previous models for California's Northern Channel Islands, producing more accurate late Pleistocene and Holocene paleogeographic reconstructions adjusted for regional GIA variability. This region has contributed significantly to our understanding of early New World coastal foragers. Sea level that was about 80-85 m lower than present at the time of the first known human occupation brought about a landscape and ecology substantially different than today. During the late Pleistocene, large tracts of coastal lowlands were exposed, while a colder, wetter climate and fluctuating marine conditions interacted with rapidly evolving littoral environments. At the close of the Pleistocene and start of the Holocene, people in coastal California faced shrinking land, intertidal, and subtidal zones, with important implications for resource availability and distribution.
The Bench 19 Bonebed at Bentiaba, Angola, is a unique concentration of marine vertebrates preserving six species of mosasaurs in sediments best correlated by magnetostratigraphy to chron C32n.1n between 71.4 and 71.64 Ma. The bonebed formed at a paleolatitude near 24°S, with an Atlantic width at that latitude approximating 2700 km, roughly half that of the current width. The locality lies on an uncharacteristically narrow continental shelf near transform faults that controlled the coastal outline of Africa in the formation of the South Atlantic Ocean. Biostratigraphic change through the Bentiaba section indicates that the accumulation occurred in an ecological time dimension within the 240 ky bin delimited by chron 32n.1n. The fauna occurs in a 10 m sand unit in the Mocuio Formation with bones and partial skeletons concentrated in, but not limited to, the basal 1–2 m. The sediment entombing the fossils is an immature feldspathic sand shown by detrital zircon ages to be derived from nearby granitic shield rocks. Specimens do not appear to have a strong preferred orientation and they are not concentrated in a strand line. Stable oxygen isotope analysis of associated bivalve shells indicates a water temperature of 18.5°C. The bonebed is clearly mixed with scattered dinosaur and pterosaur elements in a marine assemblage. Gut contents, scavenging marks and associated shed shark teeth in the Bench 19 Fauna indicate biological association and attrition due to feeding activities. The ecological diversity of mosasaur species is shown by tooth and body-size disparity and by δ13C analysis of tooth enamel, which indicate a variety of foraging areas and dietary niches. The Bench 19 Fauna was formed in arid latitudes along a coastal desert similar to that of modern Namibia on a narrow, tectonically controlled continental shelf, in shallow waters below wave base. The area was used as a foraging ground for diverse species, including molluscivorus Globidens phosphaticus, small species expected near the coast, abundant Prognathodon kianda, which fed on other mosasaurs at Bench 19, and species that may have been transient and opportunistic feeders in the area.
The behavior of H in p-GaN(Mg) at temperatures >400°C is modeled by using energies and vibration frequencies from density-functional theory to parameterize transport and reaction equations. Predictions agree semiquantitatively with experiment for the solubility, uptake, and release of the H when account is taken of a surface barrier.
We have used ion channeling to examine the lattice configuration of deuterium in Mg doped GaN grown by MOCVD. The deuterium is introduced by exposure to gas phase or ECR plasmas. A density functional approach including lattice relaxation, was used to calculate total energies for various locations and charge states of hydrogen in the wurtzite Mg doped GaN lattice. Results of channeling measurements are compared with channeling simulations for hydrogen at lattice locations predicted by density functional theory.
In this work, we investigate the structural properties of (GaIn)(AsN)/GaAs multiplequantum wells (MQW) grown at low temperature by metalorganic vapour phase epitaxy. The structural properties, in particular the In- and N-incorporation, the lattice strain (strain modulation), the structural perfection of the metastable (GaIn)(AsN) material system and the structural quality of the (GaIn)(AsN)/GaAs interfaces are investigated by means of high-resolution x-ray diffraction, transmission electron microscopy (TEM), and secondary ion mass spectrometry. We demonstrate that (GaIn)(AsN) layers of high structural quality can be fabricated up to lattice mismatches of 4%. Our experiments reveal that N and In atoms are localized in the quaternary material and no evidences of In-segregation or N-interdiffusion could be found. TEM analyses reveal a low defect density in the highly strained layers, but no clustering or interface undulation could be detected. High-resolution TEM images show that (GaIn)(AsN)/GaAs interfaces are slightly rougher than GaAs/(GaIn)(AsN) ones.
Photoluminescence (PL) spectra were measured at room temperature for GaN quantum wells (QWs) with Al0.8Ga0.2N barriers, which were grown by atmospheric-pressure metal organic chemical vapor deposition (MOCVD). The thickness of the GaN QW layers was systematically varied from one monolayer to four monolayers. We clearly observed a PL peak at a wavelength as short as 247 nm (5.03 eV) from one monolayer-thick QWs. The effective confinement energy is as large as 1.63 eV.
We have investigated the high-pressure high-temperature annealing of Mg/P-implanted GaN films using visible and ultraviolet (UV) micro-Raman spectroscopy. The results illustrate the use of Raman spectroscopy to monitor processing of GaN where fast feedback is required. The structural quality and the stress in ion-implanted GaN films was monitored in a 40nm-thin surface layer of the sample as well as averaged over the sample layer thickness. We find the nearly full recovery of the crystalline quality of ion-implanted GaN films after annealing at 1400-1500°C under nitrogen overpressures of 1.5GPa. No significant degradation effects occurred in the GaN surface layer during the annealing. The high nitrogen overpressures proved very effective in preventing the nitrogen out-diffusion from the GaN surface. Stress introduced during the annealing was monitored. Raman spectra of ion-implanted GaN films were investigated at different temperatures and excitation wavelengths to study the GaN phonon density of states.