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An electron microprobe analyzer shielded and modified to accept for analysis radioactive samples reading up to 100 R/hr is described. The following features will be illustrated and discussed: (1) biological shielding, (2) detector shielding, (3) sample transfer system, (4) remote sample loading and focusing system, (5) laboratory layout, and (6) experimental results.
In recent years, ethnoarchaeology and the use of ethnographic analogy have come under increasing criticism. Analogy seems necessary because, as post-industrial academics, archaeologists worry that they do not possess the knowledge necessary to interpret archaeological materials directly and thus must consult with coeval ‘premodern’ peoples to develop interpretive baselines. In this paper, we draw attention to a form of scholarly enquiry – 19th-century Bible customs books – that faced a similar challenge and used methodologies that parallel archaeology's use of ethnoarchaeological data. These were books written by missionaries who lived in Palestine for extended periods of time and studied Palestinian life to make sense of obscure elements of the biblical text, believing that life there had remained fundamentally unchanged for the past three thousand years. Using the Bible customs books as a kind of ‘cautionary tale’ typical of ethnoarchaeology, we argue that a consideration of this literature brings into focus some of the challenges faced by archaeologists’ use of analogy. Specifically, Bible customs books expose significant issues in how relations are conceptualized between archaeologists, others and ancients, and show how a strict empirical focus in ethnographic research can insulate key assumptions from critical scrutiny.
In Cameroon, there is a national programme engaged in the control of schistosomiasis and soil-transmitted helminthiasis. In certain locations, the programme is transitioning from morbidity control towards local interruption of parasite transmission. The volcanic crater lake villages of Barombi Mbo and Barombi Kotto are well-known transmission foci and are excellent context-specific locations to assess appropriate disease control interventions. Most recently they have served as exemplars of expanded access to deworming medications and increased environmental surveillance. In this paper, we review infection dynamics through time, beginning with data from 1953, and comment on the short- and long-term success of disease control. We show how intensification of local control is needed to push towards elimination and that further environmental surveillance, with targeted snail control, is needed to consolidate gains in preventive chemotherapy as well as empower local communities to take ownership of interventions.
Previous reports investigating adiposity and cognitive function in the population allude to a negative association, although the relationship in older adults is unclear. The aim of this study was to investigate the association of adiposity (BMI and waist:hip ratio (WHR)) with cognitive function in community-dwelling older adults (≥60 years). Participants included 5186 adults from the Trinity Ulster Department of Agriculture ageing cohort study. Neuropsychological assessment measures included the Mini-Mental State Examination (MMSE), Frontal Assessment Battery (FAB) and Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). Multi-variable linear regression models were used to assess the association between adiposity and cognitive function adjusting for insulin resistance, inflammation and cerebrovascular disease. The mean ages were 80·3 (sd 6·7), 71·0 (sd 7·3) and 70·2 (sd 6·3) years on the cognitive, bone and hypertensive cohorts, respectively. In the cognitive cohort, BMI was positively associated with immediate and delay memory, visuospatial/constructional ability, language and MMSE, and negatively with FAB (log-transformed), whereas WHR was negatively associated with attention. In the bone cohort, BMI was not associated with any cognitive domain, whereas WHR was negatively associated with visuospatial/constructional ability, attention and MMSE. In the hypertensive cohort, BMI was not associated with any cognitive domain, whereas WHR was negatively associated with immediate and delayed memory, visuospatial/constructional ability, language and MMSE and positively with FAB (log-transformed). In the cognitive and bone cohorts, the association of WHR and attention disappeared by further controlling for C-reactive protein and HbA1C. In this study of older adults, central adiposity was a stronger predictor of poor cognitive performance than BMI. Older adults could benefit from targeted public health strategies aimed at reducing obesity and obeseogenic risk factors to avoid/prevent/slow cognitive dysfunction.
The history of hill farming is traced from early times and the changes in practices described. The economic problems are analysed and the role of Government intervention has been outlined and assessed.
Research has created a basket of methods to exploit the potential of the ‘upland’ areas and these are discussed in relation to their up-take in practice and the role of the extension services in promotion.
The physical resources are briefly outlined and the contemporary economic development of the industry as influenced by the EEC and other agencies is discussed.
The impact of the demand for recreation, the need to conserve habitats and wildlife and the importance of rural amenity are examined in relation to upland agriculture and the several official organisations involved and proposals are offered. The conflicts in land use and the socio-economic problems of remote areas are discussed and appropriate policy initiatives are proposed.
22q11.2 deletion syndrome (22q11.2DS) is associated with high rates of neurodevelopmental disorder, however, the links between developmental coordination disorder (DCD), intellectual function and psychiatric disorder remain unexplored.
To establish the prevalence of indicative DCD in children with 22q11.2DS and examine associations with IQ, neurocognition and psychopathology.
Neurocognitive assessments and psychiatric interviews of 70 children with 22q11.2DS (mean age 11.2, s.d. = 2.2) and 32 control siblings (mean age 11.5, s.d. = 2.1) were carried out in their homes. Nine children with 22q11.2DS and indicative DCD were subsequently assessed in an occupational therapy clinic.
Indicative DCD was found in 57 (81.4%) children with 22q11.2DS compared with 2 (6.3%) control siblings (odds ratio (OR) = 36.7, P < 0.001). Eight of nine (89%) children with indicative DCD met DSM-5 criteria for DCD. Poorer coordination was associated with increased numbers of anxiety, (P < 0.001), attention-deficit hyperactivity disorder (ADHD) (P < 0.001) and autism-spectrum disorder (ASD) symptoms (P < 0.001) in children with 22q11.2DS. Furthermore, 100% of children with 22q11.2DS and ADHD had indicative DCD (20 of 20), as did 90% of children with anxiety disorder (17 of 19) and 96% of children who screened positive for ASD (22 of 23). The Developmental Coordination Disorder Questionnaire score was related to sustained attention (P = 0.006), even after history of epileptic fits (P = 0.006) and heart problems (P = 0.009) was taken into account.
Clinicians should be aware of the high risk of coordination difficulties in children with 22q11.2DS and its association with risk of mental disorder and specific neurocognitive deficits.
Far-UV photons (FUV, E < 13.6 eV) from hot massive stars regulate, or at least influence, the heating, ionization, and chemistry of most of the neutral interstellar medium (H i and H2 clouds). Investigating the interaction between FUV radiation and interstellar matter (molecules, atoms and grains) thus plays an important role in astrochemistry.
The Orion Bar, an interface region between the Orion A molecular cloud and the H ii region around the Trapezium cluster, is a textbook example of a strongly illuminated dense PDR (photodissociation region). The Bar is illuminated by a FUV field of a few 104 times the mean interstellar radiation field. Because of its proximity and nearly edge-on orientation, it provides a very good template to investigate the chemical content, structure, and dynamics of a strongly irradiated molecular cloud edge. We have used ALMA to mosaic a small field of the Bar where the critical transition from atomic to molecular gas takes place. These observations provide an unprecedented sharp view of this transition layer (≲ 1″ resolution or ≲ 414 AU). The resulting images (so far in the rotational emission of CO, HCO+, H13CO+, SO+, SO, and reactive ions SH+ and HOC+) show the small-scale structure in gas density and temperature, and the steep abundance gradients. The images reveal a pattern of high-density substructures, photo-ablative gas flows and instabilities at the edge of the molecular cloud. These first ALMA images thus show a more complex morphology than the classical clump/interclump static model of a PDR.
In order to quantify the chemical content in strongly FUV-irradiated gas, we have also used the IRAM-30 m telescope to carry out a complete line-survey of the illuminated edge of the Bar in the millimeter domain. Our observations reveal the presence of complex organic molecules (and precursors) that were not expected in such a harsh environment. In particular, we have reported the first detection of the unstable cis conformer of formic acid (HCOOH) in the ISM. The energy barrier to internal rotation (the conversion from trans to cis) is approximately 4827 cm−1 (≈7000 K). Hence, this detection is surprising. The low inferred trans-to-cis abundance ratio of 2.8±1.0 supports a photoswitching mechanism: a given conformer absorbs a FUV stellar photon that radiatively excites the molecule to electronic states above the interconversion barrier. Subsequent fluorescent decay leaves the molecule in a different conformer form. This mechanism, which we have specifically studied with ab initio quantum calculations, was not considered so far in astrochemistry although it can affect the structure of a variety of molecules in PDRs.
Silicon carbide dust grains are ubiquitous in circumstellar envelopes around C-rich AGB stars. However, the main gas-phase precursors leading to the formation of SiC dust have not yet been identified. To date, only three molecules containing an Si–C bond have been identified to have significant abundances in C-rich AGB stars: SiC2, SiC, and Si2C. The ring molecule SiC2 has been observed in a handful of evolved stars, while SiC and Si2C have only been detected in the C-star envelope IRC +10216. We aim to study how widespread and abundant SiC2, SiC, and Si2C are in envelopes around C-rich AGB stars and whether or not these species play an active role as gas-phase precursors of silicon carbide dust in the ejecta of carbon stars.
The molecular composition of the stellar outflows of AGB stars is determined by the stellar elemental carbon-to-oxygen abundance ratio, together with the physical circumstances in the innermost region of the outflow. Near the stellar surface, thermal equilibrium (TE) can be assumed. This leads to a certain molecular composition with a O- or C-rich signature. However, several molecular species have been detected that are not expected to be present in the inner region under the assumption of TE chemistry. As a solution to explain the presence of these unexpected species, non-equilibrium chemistry in the inner region of the outflow has been proposed. The outflows of AGB stars are generally not spherically symmetric or homogeneous, which influences the penetration of interstellar UV photons throughout the outflow. We investigate the effect of a clumpy, non-homogeneous outflow on the composition of the inner region by introducing a simple porosity formalism in our chemical model.
Planets form in disks around young stars. The planet formation process may start when the protostar and disk are still deeply embedded within their infalling envelope. However, unlike more evolved protoplanetary disks, the physical and chemical structure of these young embedded disks are still poorly constrained. We have analyzed ALMA data for 13CO, C18O and N2D+ to constrain the temperature structure, one of the critical unknowns, in the disk around L1527. The spatial distribution of 13CO and C18O, together with the kinetic temperature derived from the optically thick 13CO emission and the non-detection of N2D+, suggest that this disk is warm enough (≳ 20 K) to prevent CO freeze-out.
Results are presented from our ongoing studies of Titan using ALMA during the period 2012-2015, including a confirmation of the previous detection of vinyl cyanide (C2H3CN), as well as the first spatial map for this species on Titan. Simultaneous mapping of HC3N, CH3CN and C2H5CN reveal characteristic abundance patterns for each species that provide insight into their individual photochemical lifetimes, and help inform our understanding of Titan’s unique, time-variable atmospheric chemistry and global circulation. A time-sequence of HC3N maps covering 38 months reveals a dramatic change in the distribution of this gas consistent with high-altitude photochemical production followed by advection towards the southern (winter) pole, combined with rapid loss in the north after Titan’s 2009 seasonal equinox. The 2015 C2H3CN and C2H5CN maps show abundance peaks in Titan’s southern hemisphere, similar to those observed for the short-lived HC3N molecule. The longer-lived CH3CN, on the other hand, remains more concentrated in the north.
Parasite infection in young animals can affect host traits related to demographic processes such as survival and reproduction, and is therefore crucial to population viability. However, variation in infection among juvenile hosts is poorly understood. Experimental studies have indicated that effects of parasitism can vary with host sex, hatching order and hatch date, yet it remains unclear whether this is linked to differences in parasite burdens. We quantified gastrointestinal nematode burdens of wild juvenile European shags (Phalacrocorax aristotelis) using two in situ measures (endoscopy of live birds and necropsy of birds that died naturally) and one non-invasive proxy measure (fecal egg counts (FECs)). In situ methods revealed that almost all chicks were infected (98%), that infections established at an early age and that older chicks hosted more worms, but FECs underestimated prevalence. We found no strong evidence that burdens differed with host sex, rank or hatch date. Heavier chicks had higher burdens, demonstrating that the relationship between burdens and their costs is not straightforward. In situ measures of infection are therefore a valuable tool in building our understanding of the role that parasites play in the dynamics of structured natural populations.
Recent commentary has suggested that performance management (PM) is fundamentally “broken,” with negative feelings from managers and employees toward the process at an all-time high (Pulakos, Hanson, Arad, & Moye, 2015; Pulakos & O'Leary, 2011). In response, some high-profile organizations have decided to eliminate performance ratings altogether as a solution to the growing disenchantment. Adler et al. (2016) offer arguments both in support of and against eliminating performance ratings in organizations. Although both sides of the debate in the focal article make some strong arguments both for and against utilizing performance ratings in organizations, we believe there continue to be misunderstandings, mischaracterizations, and misinformation with respect to some of the measurement issues in PM. We offer the following commentary not to persuade readers to adopt one particular side over another but as a call to critically reconsider and reevaluate some of the assumptions underlying measurement issues in PM and to dispel some of the pervasive beliefs throughout the performance rating literature.
NGC 4945 is with D ~3-4 Mpc one of the nearest starburst galaxies known and a goldmine for molecular cloud research. A multi-line mm-wave study has been carried out towards its nuclear region with the Swedish-ESO Sub-millimetre Telescope (SEST). The study covers the frequency range from 82 GHz to 354 GHz and includes 80 transitions of 19 molecules, including rare isotope-bearing species. Applying a Large Velocity Gradient (LVG) code to the data, H2 densities and column densities of 22 molecular species are calculated. Many of these species indicate the presence of a prominent high density interstellar gas component characterized by nH2 ~105cm-3. Abundances of molecular species are calculated and compared with abundances observed toward the starburst galaxies NGC 253 and M 82 and galactic sources. Apparent is an ‘overabundance’ of HNC and CN in the nuclear environment of NGC 4945. NGC 4945 is the second known starburst galaxy with an HNC/HCN abundance ratio ≥1. Carbon, nitrogen, oxygen and sulfur isotope ratios are also determined. The data indicate that high 18O/17O, low 16O/18O and 14N/15N and perhaps also low 32S/34S ratios (6.4±0.3, 195±45, 105±25 and 13.5±2.5, respectively) are characteristic properties of a starburst environment in an advanced evolutionary stage.
We present the first measurement of the anisotropy parameter β using 3D kinematic information outside of the solar neighborhood. Our sample consists of 13 Milky Way halo stars with measured proper motions and radial velocities in the line of sight of M31. Proper motions were measured using deep, multi-epoch HST imaging, and radial velocities were measured from Keck II/DEIMOS spectra. We measure β = −0.3−0.9+0.4, which is consistent with isotropy, and inconsistent with measurements in the solar neighborhood. We suggest that this may be the kinematic signature of a relatively early, massive accretion event, or perhaps several such events.
The intensity ratios of HCO+/HCN and HNC/HCN (1-0) reveal the relative influence of star formation and active galactic nuclei (AGN) or black holes on the circum-nuclear gas of a galaxy, allowing the identification of X-ray dominated regions (XDRs) and Photon-dominated regions (PDRs). It is not always clear in the literature how this intensity ratio calculation has been, or should be performed. This paper discusses ratio calculation methods for interferometric data.