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During 1990 we surveyed the southern sky using a multi-beam receiver at frequencies of 4850 and 843 MHz. The half-power beamwidths were 4 and 25 arcmin respectively. The finished surveys cover the declination range between +10 and −90 degrees declination, essentially complete in right ascension, an area of 7.30 steradians. Preliminary analysis of the 4850 MHz data indicates that we will achieve a five sigma flux density limit of about 30 mJy. We estimate that we will find between 80 000 and 90 000 new sources above this limit. This is a revised version of the paper presented at the Regional Meeting by the first four authors; the surveys now have been completed.
Non-typhoidal Salmonella are an important but poorly characterized cause of paediatric diarrhoea in developing countries. We conducted a hospital-based case-control study in children aged <5 years in Ho Chi Minh City to define the epidemiology and examine risk factors associated with Salmonella diarrhoeal infections. From 1419 diarrhoea cases and 571 controls enrolled between 2009 and 2010, 77 (5·4%) diarrhoea cases were stool culture-positive for non-typhoidal Salmonella. Salmonella patients were more likely to be younger than controls (median age 10 and 12 months, respectively) [odds ratio (OR) 0·97; 95% confidence interval (CI) 0·94–0·99], to report a recent diarrhoeal contact (8·1% cases, 1·8% controls; OR 5·98, 95% CI 1·8–20·4) and to live in a household with >2 children (cases 20·8%, controls 10·2%; OR 2·32, 95% CI 1·2–4·7). Our findings indicate that Salmonella are an important cause of paediatric gastroenteritis in this setting and we suggest that transmission may occur through direct human contact in the home.
In people with bulimic eating disorders, exposure to high-calorie foods can result in increases in food craving, raised subjective stress and salivary cortisol concentrations. This cue-induced food craving can be reduced by repetitive transcranial magnetic stimulation (rTMS). We investigated whether rTMS has a similar effect on salivary cortisol concentrations, a measure of hypothalamic–pituitary–adrenal axis (HPAA) activity.
We enrolled twenty-two female participants who took part in a double-blind randomized sham-controlled trial on the effects of rTMS on food craving. Per group, eleven participants were randomized to the real or sham rTMS condition. The intervention consisted of one session of high-frequency rTMS delivered to the left dorsolateral prefrontal cortex (DLPFC). Salivary cortisol concentrations were assessed at four time points throughout the 90-min trial. To investigate differences in post-rTMS concentrations between the real and sham rTMS groups, a random-effects model including the pre-rTMS cortisol concentrations as covariates was used.
Salivary cortisol concentrations following real rTMS were significantly lower compared with those following sham rTMS. In this sample, there was also a trend for real rTMS to reduce food craving more than sham rTMS.
These results suggest that rTMS applied to the left DLPFC alters HPAA activity in people with a bulimic disorder.
The UK was one of few European countries to document a substantial wave of pandemic (H1N1) 2009 influenza in summer 2009. The First Few Hundred (FF100) project ran from April–June 2009 gathering information on early laboratory-confirmed cases across the UK. In total, 392 confirmed cases were followed up. Children were predominantly affected (median age 15 years, IQR 10–27). Symptoms were mild and similar to seasonal influenza, with the exception of diarrhoea, which was reported by 27%. Eleven per cent of all cases had an underlying medical condition, similar to the general population. The majority (92%) were treated with antiviral drugs with 12% reporting adverse effects, mainly nausea and other gastrointestinal complaints. Duration of illness was significantly shorter when antivirals were given within 48 h of onset (median 5 vs. 9 days, P=0·01). No patients died, although 14 were hospitalized, of whom three required mechanical ventilation. The FF100 identified key clinical and epidemiological characteristics of infection with this novel virus in near real-time.
Largely because of the influence of Moffitt's useful distinction between adolescence-limited and life-course persistent antisocial behavior, it has become increasingly common to view problem behavior that makes its first appearance in adolescence as developmentally normative. This study prospectively examined the lives of individuals in the NICHD Study of Early Child Care and Youth Development whose patterns of antisocial behavior varied with respect to age of onset and stability from kindergarten through age 15. Consistent with past research, early-onset, persistently deviant youth experienced more contextual adversity and evinced higher levels of intraindividual disadvantages than their peers from infancy through midadolescence. However, relative to youth who never showed significantly elevated antisocial behavior through age 15, children who showed antisocial behavior primarily in adolescence also were more disadvantaged from infancy forward, as were youth who only demonstrated significant externalizing problems in childhood. Findings generally replicated across sex and did not vary as a function of whether antisocial behavior groups were defined using T-scores normed within sex or identified using an empirically driven grouping method applied to raw data.
Studies of patients with anorexia nervosa (AN) have shown that they do not perform well in set-shifting tasks but little is known about the neurobiological correlates of this aspect of executive function. The aim of this study was to measure serum brain-derived neurotrophic factor (BDNF) and to establish whether set-shifting difficulties are present in people with current AN and in those recovered from AN, and whether serum BDNF concentrations are correlated with set-shifting ability.
Serum BDNF concentrations were measured in 29 women with current AN (AN group), 18 women who had recovered from AN (ANRec group) and 28 age-matched healthy controls (HC group). Set-shifting was measured using the Wisconsin Card Sorting Test (WCST). Eating-related psychopathology and depressive, anxiety and obsessive–compulsive symptomatology were evaluated using the Eating Disorder Examination Questionnaire (EDEQ), the Hospital Anxiety and Depression Scale (HADS), and the Maudsley Obsessive–Compulsive Inventory (MOCI) respectively.
Serum BDNF concentrations (mean±s.d.) were significantly lower in the AN group (11.7±4.9 ng/ml) compared to the HC group (15.1±5.5 ng/ml, p=0.04) and also compared to the ANRec group (17.6±4.8 ng/ml, p=0.001). The AN group made significantly more errors (total and perseverative) in the WCST relative to the HC group. There was no significant correlation between serum BDNF concentrations and performance on the WCST.
Serum BDNF may be a biological marker for eating-related psychopathology and of recovery in AN. Longitudinal studies are needed to explore possible associations between serum BDNF concentrations, illness and recovery and neuropsychological traits.
Attentional difficulties reported in individuals with anorexia nervosa (AN) may be due to preferential processing of disease-salient stimuli at a pre-attentive or at a conscious level or to a general problem in attention. Attentional difficulties may be associated with duration of illness.
Female participants with AN (restricting subtype; n=24) and healthy comparison women (n=24) were randomly allocated to subliminal or supraliminal exposure to visual stimuli (food, neutral and aversive images) while performing the 1-back and 2-back working-memory tasks.
Participants with AN made fewer errors than the healthy comparison group in the subliminal condition but significantly more errors in the supraliminal condition [condition×group interaction, F(1, 44)=6.82, p<0.01]: this was irrespective of stimulus type (food, neutral and aversive) and task (1-back or 2-back). The total number of errors made correlated positively with the duration of the AN for both the 1-back task (rs=0.46, p<0.05) and for the 2-back task (rs=0.53, p<0.01).
Decreased ability to concentrate in the presence of explicit distracters is a feature of AN and is associated with longer duration of illness. This phenomenon could be addressed in psychological interventions.
We examined the serological characteristics of 774 invasive meningococcal isolates collected through an active laboratory-based surveillance system in Scotland from 1994 to 1999. Of these, 72–73% of isolates were tested for susceptibility to several antimicrobial agents. Meningococci with high-level resistance to sulphadiazine had a prevalence of 10% and incidence of 0·22 per 100000 population. High-level resistance to penicillin and other antibiotics was not detected. The prevalence of moderate penicillin resistant meningococci was 8·3%. There was no increase in moderate penicillin resistant meningococcal isolates during the study period, but there were temporal and geographic variations. The estimated incidence of moderate penicillin resistant meningococci was 0·15 per 100000 population. High and low incidence of moderate penicillin resistant meningococci appeared to correlate with the number of doses of penicillin prescribed in some geographic locations. The majority of moderate penicillin resistant isolates belonged to serogroups B (52·2%) and C (39·2%). However, the prevalence of moderate penicillin resistance in serogroup W135 was substantially higher (51·7%) than serogroups B (7·8%) and C (7·6%). Serogroup W135 accounted for a higher proportion of moderate penicillin resistance (8·7%) than disease (1%). There was no predominant penicillin resistant serotype/subtype within any serogroup. Constant surveillance is necessary to monitor the emergence and spread of resistance and to guide appropriate public health interventions in preventing drug resistant meningococci.
InAs/AlGaAs quantum dot infrared photodetectors based on bound-to-bound intraband transitions in undoped InAs quantum dots are reported. AlGaAs blocking layers were employed to achieve low dark current. The photoresponse peaked at 6.2 μm. At 77 K and –0.7 V bias the responsivity was 14 mA/W and the detectivtiy, D*, was 1010 cmHz1/2/W.
Material interaction during integration of tungsten gate stack for 1 Gb DRAM was investigated by Transition Electron Microscopy (TEM), X-ray Diffraction analysis (XRD) and Auger Electron Spectroscopy (AES). During selective side-wall oxidation tungsten gate conductor undergoes a structural transformation. The transformation results in the reduction of tungsten crystal lattice spacing, re-crystallization of tungsten and/or growth of grains. During a highly selective oxidation process, a relatively small but noticeable amount of oxygen was incorporated into the tungsten layer. The incorporation of oxygen is attributed to the formation of a stable WO x (x<2) composite.
We have studied the effects of nitridation on the leakage current of thin (7-8 nm) gate or tunnel oxides. A polarity dependence of the tunneling current has been found this behavior is related to the presence of a thin silicon oxynitride layer at the SiO2/Si-substrate interface. The oxynitride layer lowers the tunneling current when electrons are injected from the interface where the oxynitride is located (substrate injection). The current flowing across the oxide when electrons are injected from the opposite interface (gate injection) is not influenced by the oxynitride. The increase of nitrogen concentration leads to a decrease of the tunneling current for substrate electron injection.
The Σ5 (31O)/ symmetric tilt grain boundary (STGB) in the face centered cubic (FCC) metal aluminum with 1at% copper has been studied. The model grain boundary has been fabricated by ultra-high vacuum diffusion bonding of alloy single crystals. The segregation of the copper has been encouraged by annealing the sample after bonding at 200 °C. TEM samples of this FCCmaterial were prepared with a new low voltage ion mill under very low angles.
The atomic structure of the Σ5(310)/ STGB for this system was modeled with electronic structure calculations. These theoretical calculations of the interface structure indicate that the Cu atoms segregate to distinct sites at the interface. High resolution electron microscopy (HRTEM) and analytical electron microscopy including electron energy spectroscopic imaging and X-ray energy dispersive spectrometry have been used to explore the segregation to the grain boundary. The HRTEM images and the analytical measurements were performed using different kinds of microscopes, including a Philips CM300 FEG equipped with an imaging energy filter. The amount of the segregated species at the interface was quantified in a preliminary way. To determine the atomic positions of the segregated atoms at the interface, HRTEM coupled with image simulation and a first attempt of a holographic reconstruction from a through-focal series have been used.
The dominant factor in determining the atomic structure of grain boundaries is the crystal structure of the material, e.g. FCC vs. BCC. However, for a given crystal structure, the structure of grain boundaries can be influenced by electronic effects unique to the element comprising the crystal. Understanding and modeling the influence of electronic structure on defect structures is a key ingredient for successful atomistic simulations of materials with more complicated crystal structures than FCC. We have found that grain boundary structure is a critical test for interatomic potentials. To that end, we have fabricated the nominally identical Σ5 (310)/ symmetric tilt grain boundary in three different BCC metals (Nb, Mo, and Ta) by diffusion bonding precisely oriented single crystals. The structure of these boundaries have been determined by high resolution transmission electron microscopy. The boundaries have been found to have different atomic structures. The structures of these boundaries have been modeled with atomistic simulations using inter-atomic potentials incorporating angularly dependent d–state interactions, as obtained from Model Generalized Pseudopotential Theory. We report here new experimental and theoretical results for Ta
The speed with which tracks form as a result of trampling on exposed ground surfaces in Antarctica was investigated in the McMurdo Sound and Dry Valleys regions, by a simple treading experiment. Distinct tracks formed with fewer than 20 foot passes — as measured by stone cover, surface soil exposure, and track width — and they continued to develop with increasing traffic levels. Track development was rapid and most obvious on sandy gravel soils with a pebbly desert pavement, but slower and less distinct on soils with an extensive cover of surface boulders.
The persistence of human impact from ground disturbances, which occurred up to 30 years previously, when pits were dug during field science investigations, was assessed using a range of previously defined criteria. Recently disturbed sites, where some action had been taken to restore the site immediately after disturbance, showed the least overall impact. Impacts persisted longer at sites where no restoration had been undertaken, but the remaining impact varied with factors such as exposure to wind and the age of the land surface. These results demonstrate the fragility of Antarctic soil surfaces and the terrestrial environment, as well as the long time-scales for recovery of Antarctic ground-surface disturbances.
A finite group G is efficient if it has a presentation on n generators and n + m relations, where m is the minimal number of generators of the Schur multiplier M (G)of G. The deficiency of a presentation of G is r–n, where r is the number of relations and n the number of generators. The deficiency of G, def G, is the minimum deficiency over all finite presentations of G. Thus a group is efficient if def G = m. Both the problem of efficiency and the converse problem of inefficiency have received considerable attention recently; see for example , ,  and .
There are strong moral overtones associated with eating behaviour
with this goes the
contemporary assumption that anyone can choose their shape and weight if
they try hard
enough. Arguably, it is this false gospel that has led to the recent
increase in bulimia nervosa (BN).
Women struggling to attain an idealized shape have drastically to subvert
their bodies' homeostatic
mechanisms: the battle is rarely won and eventually, the victim turns for
to escape the scars
and trauma. On the other hand, the shimmering vision of anorexia nervosa
(AN) appears to support the myth.
A constant depth scratch test (CDST) has been recently developed to quantify the shear strength of film-substrate interfaces. This test is capable of measuring interfacial adhesion as a function of position on the sample surface during a continuous scratch. Unlike many of the currently available tests which are applicable to a limited array of materials systems, or are experimentally complex, this test is quite versatile, and is relatively straightforward to conduct and interpret because of the constant depth geometry. The theoretical basis and the experimental set-up for the test have been previously presented. In this paper, extensions of the theoretical formulation to account for different debonding behaviors of different film-substrate systems are discussed. Experimental results generated with a number of systems, including chromium on glass, gold on aluminum nitride, gold on aluminum nitride with a chromium inter-layer, and polycrystalline diamond on aluminum nitride are presented.
Soils and the underlying permafrost from undisturbed sites and sites that had been disturbed by construction activities at Marble Point and Pram Point in the McMurdo Sound region were sampled from excavated pits and drill cores. Gravimetric moisture (ice) contents and particle size distribution were determined. Volumetric moisture contents were calculated from these results. At undisturbed sites soil moisture contents within the active layer (to c. 60 cm depth) were low and ranged from 0.5% by weight at the soil surface to 10% above the permafrost. The permafrost was generally completely saturated with ice, but sometimes contained considerable excess ice, with ice contents rising as high as 80% by volume. At disturbed sites, soil moisture contents within the active layer were similar to those of the undisturbed sites (generally <10% by weight) but within the permafrost, moisture contents were lower and less variable than in the undisturbed sites, rarely exceeding 20% by weight. The release of considerable quantities of water from the permafrost as a result of land disturbance during construction activities caused stream flows, soil shrinkage, land slumping and salinisation, resulting in significant permanent environmental damage. At Marble Point there has been no significant re-establishment of icy permafrost in the disturbed soils in the 30 years since land disturbance occurred.
A set of simple criteria for visual assessment of the effects of low-intensity fieldwork in ice-free areas of Antarctica was developed. These criteria were tested by using them to examine the impact of soil science investigations, both immediately and some time after disturbance, at Marble Point and at Cape Evans, on the shores of McMurdo Sound, Antarctica. The use of these criteria showed that for some types of impacts there had been a marked recovery of the surface with time, ranging from 22 months to 30 years. This was apparently due to repeated freeze and thaw of the soil surface and, to a lesser extent, to the influence of wind, which had partly or completely obliterated some of the earlier disturbances. More durable features remained, while deeper surface impressions, such as old soil inspection pits and vehicle tracks, showed little recovery after more than 30 years. Some biological colonisation of areas disturbed 30 years previously was occurring.