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Limpets and barnacles are important components of intertidal assemblages worldwide. This study examines the effects of barnacles on the foraging behaviour of the limpet Patella vulgata, which is the main algal grazer in the North-west Atlantic. The behaviour of limpets on a vertical seawall on the Isle of Man (UK) was investigated using autonomous radio-telemetry, comparing their activity patterns on plots characterized by dense barnacle cover and plots from which the barnacles had been removed. Limpet behaviour was investigated at mid-shore level, but two different elevations were considered. This experiment revealed a significant effect of barnacle cover on the activity of P. vulgata. Limpets on smooth surfaces spent a greater proportion of total time active than did limpets on barnacles. Movement activity was also greater in areas that were lower down in the tidal range. In general, limpets were either predominantly active during diurnal high or nocturnal low tides and always avoided nocturnal high tides. Individuals on barnacles at the higher elevation concentrated their activity during nocturnal low water. All the other groups of limpets (smooth surfaces on the upper level and all individuals on the lower shore) had more excursions centred around daylight hours with an equal distribution of activity between periods of low and high water. Inter-individual variability was, however, pronounced.
The rocky shores of the north-east Atlantic have been long studied. Our focus is from Gibraltar to Norway plus the Azores and Iceland. Phylogeographic processes shape biogeographic patterns of biodiversity. Long-term and broadscale studies have shown the responses of biota to past climate fluctuations and more recent anthropogenic climate change. Inter- and intra-specific species interactions along sharp local environmental gradients shape distributions and community structure and hence ecosystem functioning. Shifts in domination by fucoids in shelter to barnacles/mussels in exposure are mediated by grazing by patellid limpets. Further south fucoids become increasingly rare, with species disappearing or restricted to estuarine refuges, caused by greater desiccation and grazing pressure. Mesoscale processes influence bottom-up nutrient forcing and larval supply, hence affecting species abundance and distribution, and can be proximate factors setting range edges (e.g., the English Channel, the Iberian Peninsula). Impacts of invasive non-native species are reviewed. Knowledge gaps such as the work on rockpools and host–parasite dynamics are also outlined.
The potential advantages of synchrotron sources for x-ray fluorescence analysis have been discussed by several authors. These advantages include high incident flux, tunable excitation energies using crystal monochromators, and reduction of scattered background due to polarization effects. Minimum detectable limits have both been calculated and measured, and have demonstrated the improvements that can be achieved vising synchrotron sources. In this paper we present results obtained using tunable, monochromatic excitation and a high resolution lithium-drifted silicon, Si(Li), spectrometer for the quantitative analysis of a variety of sample types. Our experiments were designed to investigate the advantages and limitations of tunable monochromatic excitation with respect to optimum sensitivity, accuracy, and elemental selectivity in energy dispersive x-ray fluorescence analysis.
X-ray microscopy is a field that has developed rapidly in recent years. Two different approaches have been used. Zone plates have been employed to produce focussed beams with sizes as low as 0.07 pm for x-ray energies below 1 keV. Images of biological materials and elemental maps for major and minor low Z have been produced using above and below absorption edge differences. At higher energies collimators and focussing mirrors have been used to make small diameter beams for excitation of characteristic K— or L-x rays of all elements in the periodic
Let Un be an n-dimensional unitary space with inner product (u, v). For vectors u1, . . . , ur ∊ Un, r ≤ n, let denote the Grassmann exterior product (4) of the ut; it is a vector in Um where m = nCr. If also , then is the determinant of the r X r matrix If A is a linear transformation of Un to itself, the rth compound of A is defined by
Let K be a commutative field, let GL(n, K) be the multiplicative group of all non-singular n × n matrices with elements from K, and let SL(n, K) be the subgroup of GL(n, K) consisting of all matrices in GL(n, K) with determinant one. We denote the determinant of matrix A by |A|, the identity matrix by In, the companion matrix of polynomial p(λ) by C(p(λ)), and the transpose of A by AT. The multiplicative group of nonzero elements in K is denoted by K*. We let GF(pn) denote the finite field having pn elements.
Limited research has suggested that higher lambing densities increase interference from foreign ewes at lambing which disrupts the ewe-lamb bond and compromises lamb survival. This may be particularly evident in mobs of twin-bearing ewes compared to single-bearing ewes because a greater number of lambs are born per day. Therefore, we hypothesised that; (i) decreasing the mob size of ewes at lambing has a greater impact on the survival of twin-born lambs than single-born lambs; (ii) the relationship between mob size and lamb survival can be explained by differences in the rate of interaction with foreign ewes and lambs at lambing; and (iii) ewes will utilise a limited area of the paddock at lambing and thus lambing density will be defined by the distribution of ewes in the paddock rather than the paddock area. Merino ewes were allocated into a 2×2 factorial combination of ewe pregnancy status (single- or twin-bearing) and mob size (high (n=130 ewes) or low (n=50 ewes)) on day 140 from the start of joining. Each treatment had two replicates excepting the low mob size for twins which had a third replicate. Ewes lambed at a stocking rate of 11 ewes/ha. Feed-on-offer during lambing exceeded 2400 kg dry matter (DM)/ha. Ewe-lamb behaviour was observed and dead lambs were autopsied over 11 days during the peak of lambing. The distribution of ewes in each paddock was recorded every 2 h during daylight hours by counting the number of ewes occupying 2500 m2 grids. The proportion of ewes and their newborn progeny which interacted with foreign ewes at lambing did not differ between the high and low mob sizes for single- (24.9% v. 20.8%) or twin-bearing ewes (14.3% v. 19.6%; P=0.74). Similarly, interaction with foreign lambs did not differ between the high and low mob sizes for single- (14.5% v. 25.2%) and twin-bearing ewes (34.5% v. 26.4%; P=0.44). The distribution of ewes within the paddock did not differ between treatments (P=0.95). On average, single-bearing ewes which lambed at the high and low mob sizes occupied 34% and 36% of the paddock during daylight hours, and the corresponding values for twin-bearing ewes were 40% and 43%. Survival of twin-born lambs was lower than single-born lambs (75.3% v. 87.9%; P<0.01), however, lamb survival was not influenced by mob size regardless of birth type. These results suggest that higher mob sizes may not compromise lamb survival when feed-on-offer during lambing exceeds 2400 kg DM/ha.
We investigated risk factors for severe acute lower respiratory infections (ALRI) among hospitalised children <2 years, with a focus on the interactions between virus and age. Statistical interactions between age and respiratory syncytial virus (RSV), influenza, adenovirus (ADV) and rhinovirus on the risk of ALRI outcomes were investigated. Of 1780 hospitalisations, 228 (12.8%) were admitted to the intensive care unit (ICU). The median (range) length of stay (LOS) in hospital was 3 (1–27) days. An increase of 1 month of age was associated with a decreased risk of ICU admission (rate ratio (RR) 0.94; 95% confidence intervals (CI) 0.91–0.98) and with a decrease in LOS (RR 0.96; 95% CI 0.95–0.97). Associations between RSV, influenza, ADV positivity and ICU admission and LOS were significantly modified by age. Children <5 months old were at the highest risk from RSV-associated severe outcomes, while children >8 months were at greater risk from influenza-associated ICU admissions and long hospital stay. Children with ADV had increased LOS across all ages. In the first 2 years of life, the effects of different viruses on ALRI severity varies with age. Our findings help to identify specific ages that would most benefit from virus-specific interventions such as vaccines and antivirals.
Background:ATP8A2 mutations have only recently been associated with human disease. We present the clinical features from the largest cohort of patients with this disorder reported to date. Methods: An observational study of 9 unreported and 2 previously reported patients with biallelic ATP8A2 mutations was carried out at multiple centres. Results: The mean age of the cohort was 9.4 years old (range: 2.5-28 yrs). All patients demonstrated developmental delay, severe hypotonia and movement disorders: chorea/choreoathetosis (100%), dystonia (27%) or facial dyskinesia (18%). Hypotonia was apparent at birth (70%) or before 6 months old (100%). Optic atrophy was observed in 75% of patients who had a funduscopic examination. MRI of the brain was normal for most patients with a small proportion showing mild cortical atrophy (30%), delayed myelination (20%) and/or hypoplastic optic nerves (20%). Epilepsy was seen in two older patients. Conclusions:ATP8A2 gene mutations have emerged as a cause of a novel phenotype characterized by developmental delay, severe hypotonia and hyperkinetic movement disorders. Optic atrophy is common and may only become apparent in the first few years of life, necessitating repeat ophthalmologic evaluation. Early recognition of the cardinal features of this condition will facilitate diagnosis of this disorder.
A combination of better management and genetic selection for good health and fertility would provide a more effective long term solution for economic loss due to diseases and poor fertility. This would also help to address public concerns about the use of medical treatment in milk production. A balance in the genetic improvement of health and fertility together with milk production could be achieved through their inclusion in national genetic selection indices, for which genetic parameters are needed. One of the main objectives of this study was to estimate genetic parameters for various disease and fertility traits in the UK dairy cattle population, using records from a national recording scheme run by Livestock Services UK Ltd. Genetic analysis of traits recorded as present or absent (binary traits; e.g. diseases) requires the use of non-linear threshold models, because linear models require normality assumptions (e.g., Gianola 1982). The other objective of this study was to estimate genetic parameters for binary disease and fertility traits based on threshold animal models and to compare results with those from linear animal models.
In ewe lambs, acceleration of growth and accumulation of both muscle and fat leads to earlier sexual maturity and better reproductive performance. The next stage in the development of this theme is to test whether these aspects of growth in young ewes affect milk production in their first lactation and the growth of their first progeny. We studied 75 young Merino ewes that had known phenotypic values for depth of eye muscle (EMD) and fat (FAT), and known Australian Sheep Breeding Values for post-weaning weight (PWT) and depths of eye muscle (PEMD) and fat (PFAT). They lambed for the first time at 1 year of age. Their lambs were weighed weekly from birth to weaning at 10 weeks to determine live weight gain and weaning weight. Progeny birth weight was positively associated with live weight gain and weaning weight (P<0.001). The PWT of the mothers was positively associated with birth weight (P<0.01), live weight gain and weaning weight of the progeny (P<0.05); however, these progeny traits were not influenced by EMD, FAT, PEMD, PFAT of the mothers (P>0.05). The PWT of the sire was positively associated with live weight gain (P<0.05) and weaning weight of the progeny (P<0.01). At around day 20 postpartum, we measured milk production and milk composition (fat, protein, lactose, total solids). Milk production was influenced positively by birth type (single or twin; P<0.05) and negatively by birth weight (P<0.05), but not by mother phenotype or genotype, sire genotype of the mother or the sex of the progeny (P>0.05). The concentrations of fat, protein, lactose and total solids in the milk were not affected by the phenotype or genotype of the mothers or of the sires of the mothers, or by the sex of the progeny (P>0.05). We conclude that selection of young Merino ewes for better growth, and more rapid accumulation of muscle and fat, will lead to progeny that are heavier at birth, grow faster and are heavier at weaning. Moreover, milk production and composition do not seem to be affected by the genetic merit of the mother for post-weaning live weight or PEMD or PFAT. Therefore, Merino ewes can lamb at 1 year of age without affecting the production objectives of the Merino sheep industry.
Ortles mountain (3905 m a.s.l.), South Tyrol, Italy, is the highest mountain of the Eastern European Alps, and its upper glacier, Alto dell’Ortles, presents a unique opportunity to obtain the first paleoenvironmental record from an ice core in this area. To study the suitability of this glacier as a drilling site, in 2009 we performed the first preliminary study of its glaciological characteristics at ˜3830 m a.s.l. The maximum thickness is ˜75 m, and lamination of the exposed ice layers is excellent down to bedrock. Firn and ice lenses were observed in a 10 m shallow core, and the firn/ice transition was below ˜24m. The seasonal chemical signal is clearly preserved only within the uppermost 2008 and 2009 snow/firn. A simple mass-balance model, the incipient ‘smoothing’ of the chemical record, and the observed ice lenses provide evidence that melting, infiltration and refreezing cycles occurred within the firn layers formed before 2008. Nevertheless, the mass balance of the upper part of Alto dell’Ortles was positive (˜800mma_1) during the last few years. We suggest that an environmental history is likely to be well preserved only within the ice layers formed before ˜1980, when summer air temperature was ˜2°C colder than today in this area. Clearly the continued warming trend predicted to occur over the next few decades, and the consequent increase in frequency and/or intensity of infiltration processes, will endanger the preservation of the glacial archive conserved in the deep ice layers of Ortles mountain.
Voyager discovered nine simple organic molecules in the atmosphere of Titan. Complex organic solids, called tholins, produced by irradiation of simulated Titanian atmosphere are consistent with measured properties of Titan from ultraviolet to microwave frequencies, and are the likely main constituents of the observed red aerosols. The tholins contain many of the organic building blocks central to life on Earth. At least 100 m and possibly kms thickness of complex organics have been produced on Titan during the age of the solar system, and may exist today as submarine deposits beneath an extensive ocean of simple hydrocarbons.
There is now evidence that at least some cometary nuclei are dark and red. Cometary ices prepared from combinations of CH4 with H2O and sometimes NH3 were irradiated at 77 K by corona discharge. CH4 - containing ice reddened and darkened at a dose ~1011 erg cm−2 over a period of ~1 hour. Upon evaporation of the now yellowish, irradiated ice, a slightly yellowish colored solid film remains on the walls of the container at room temperature. Transmission measurements of this organic film (called cometary tholin) were made from 0.2 μm to 50 μm wavelength. Strong UV absorption is seen from 0.45 μm to 0.2 μm. Above 0.45 μm, the spectrum remains flat to ~1.3 μm in the near infrared, except for a very small feature near 1.15 μm. A medium sized feature appears centered at 1.4 μm with shoulders at both sides and a nearby weaker feature at 1.52 μm. A strong feature appears at 1.9 μm accompanied by a smaller feature at 1.78 μm. in the region 2.5 μm to 50 μm, the infrared spectrum was taken by dispersing the film in a CsI matrix. Bands are found at 2.92(M), 3.36(S), 3.40(S), 3.46(M), 3.48(M), 5.75(M), 5.99(S), 6.21(M), 6.83(M), 7.30(S), 7.81(W), 8.89(M), 9.26(M), 20.00(W), 22.22(W), and 28.57(W) micrometers, suggesting complex organics including alkane, alkene, aldehyde, and carboxylic acid functional groups. These results are also relevant to UV and cosmic ray processing of interstellar grains, and to icy bodies in the outer solar system.
In the prevailing icy conglomerate model of the cometary nucleus, the outer surface is processed by galactic cosmic rays in the Oort cloud. Most ices composed of CH4, along with H2O and/or NH3, studied in our laboratory redden and darken upon charged particle irradiation from a high frequency corona discharge at 77 K. Spectral reflectance relative to a BaSO4 standard in the wavelength interval 0.39 μm to 0.70 μm was measured for incidence angle, i = 0° and emission angle, ε = −4°. CH4-containing ice at 77 K was modified at a dose ~1011 erg cm−2 over a period of ~1 hour. Progressive darkening followed continued irradiation. The ratio of the red to blue reflectance [R(λ = 0.70 μm)/R(λ = 0.40 μm)] changed from 0.9 to ~1.4. Using techniques of ellipsometric polarimetry, we are investigating the detailed optical properties (complex refractive index) of these ices before and after irradiation. These results may then be compared with the properties of cometary coma particles predicted by recent light scattering models to determine which classes of laboratory-produced materials best match the population of dark, reddish particles which seem to be prevalent in some cometary comae.
Arterial wall thickening, stimulated by low-grade systemic inflammation, underlies many cardiovascular events. As diet is a significant moderator of systemic inflammation, the dietary inflammatory index (DIITM) has recently been devised to assess the overall inflammatory potential of an individual’s diet. The primary objective of this study was to assess the association of the DII with common carotid artery–intima-media thickness (CCA–IMT) and carotid plaques. To substantiate the clinical importance of these findings we assessed the relationship of DII score with atherosclerotic vascular disease (ASVD)-related mortality, ischaemic cerebrovascular disease (CVA)-related mortality and ischaemic heart disease (IHD)-related mortality more. The study was conducted in Western Australian women aged over 70 years (n 1304). Dietary data derived from a validated FFQ (completed at baseline) were used to calculate a DII score for each individual. In multivariable-adjusted models, DII scores were associated with sub-clinical atherosclerosis: a 1 sd (2·13 units) higher DII score was associated with a 0·013-mm higher mean CCA–IMT (P=0·016) and a 0·016-mm higher maximum CCA–IMT (P=0·008), measured at 36 months. No relationship was seen between DII score and carotid plaque severity. There were 269 deaths during follow-up. High DII scores were positively associated with ASVD-related death (per sd, hazard ratio (HR): 1·36; 95 % CI 1·15, 1·60), CVA-related death (per sd, HR: 1·30; 95 % CI 1·00, 1·69) and IHD-related death (per sd, HR: 1·40; 95 % CI 1·13, 1·75). These results support the hypothesis that a pro-inflammatory diet increases systemic inflammation leading to development and progression of atherosclerosis and eventual ASVD-related death.
Our understanding of the complex relationship between schizophrenia symptomatology and etiological factors can be improved by studying brain-based correlates of schizophrenia. Research showed that impairments in value processing and executive functioning, which have been associated with prefrontal brain areas [particularly the medial orbitofrontal cortex (MOFC)], are linked to negative symptoms. Here we tested the hypothesis that MOFC thickness is associated with negative symptom severity.
This study included 1985 individuals with schizophrenia from 17 research groups around the world contributing to the ENIGMA Schizophrenia Working Group. Cortical thickness values were obtained from T1-weighted structural brain scans using FreeSurfer. A meta-analysis across sites was conducted over effect sizes from a model predicting cortical thickness by negative symptom score (harmonized Scale for the Assessment of Negative Symptoms or Positive and Negative Syndrome Scale scores).
Meta-analytical results showed that left, but not right, MOFC thickness was significantly associated with negative symptom severity (βstd = −0.075; p = 0.019) after accounting for age, gender, and site. This effect remained significant (p = 0.036) in a model including overall illness severity. Covarying for duration of illness, age of onset, antipsychotic medication or handedness weakened the association of negative symptoms with left MOFC thickness. As part of a secondary analysis including 10 other prefrontal regions further associations in the left lateral orbitofrontal gyrus and pars opercularis emerged.
Using an unusually large cohort and a meta-analytical approach, our findings point towards a link between prefrontal thinning and negative symptom severity in schizophrenia. This finding provides further insight into the relationship between structural brain abnormalities and negative symptoms in schizophrenia.
Gender equity is imperative to the attainment of healthy lives and wellbeing of all, and promoting gender equity in leadership in the health sector is an important part of this endeavour. This empirical research examines gender and leadership in the health sector, pooling learning from three complementary data sources: literature review, quantitative analysis of gender and leadership positions in global health organisations and qualitative life histories with health workers in Cambodia, Kenya and Zimbabwe. The findings highlight gender biases in leadership in global health, with women underrepresented. Gender roles, relations, norms and expectations shape progression and leadership at multiple levels. Increasing women's leadership within global health is an opportunity to further health system resilience and system responsiveness. We conclude with an agenda and tangible next steps of action for promoting women's leadership in health as a means to promote the global goals of achieving gender equity.
A 480 year record of the oxygen-isotope ratios, dust content, chemical species and net accumulation from ice cores drilled in 1989 90 on Dyer Plateau in the Antarctic Peninsula is presented. The continuous analyses of small (sub-annual) samples reveal well-preserved annual variations in both sulfate content and δ18O, thus allowing an excellent time-scale to be established.
This history reveals a recent pronounced warming in which the last two decades have been among the warmest in the last five centuries. Furthermore, unlike in East Antarctica, on Dyer Plateau conditions appear to have been fairly normal from AD 1500 to 1850 with cooler conditions from 1850 to 1930 and a warming trend dominating since 1930. Reconstructed annual layer thicknesses suggest an increase in net accumulation beginning early in the 19th century and continuing to the present. This intuitive conflict between increasing net accumulation and depleted δ18O (cooler climate) in the 19th century appears widespread in the peninsula region and challenges our understanding of the physical relationships among moisture sources, air temperatures and snow accumulation. The complex meteorological regime in the Antarctic Peninsula region complicates meaningful interpretation of proxy indicators and results in a strong imprint of local high-frequency processes upon the larger-scale climate picture.
Dietary advice is fundamental in the prevention and management of type 2 diabetes (T2DM). Advice is improved by individual assessment but existing methods are time-consuming and require expertise. We developed a twenty-five-item questionnaire, the UK Diabetes and Diet Questionnaire (UKDDQ), for quick assessment of an individual’s diet. The present study examined the UKDDQ’s repeatability and relative validity compared with 4 d food diaries.
The UKDDQ was completed twice with a median 3 d gap (interquartile range=1–7 d) between tests. A 4 d food diary was completed after the second UKDDQ. Diaries were analysed and food groups were mapped on to the UKDDQ. Absolute agreement between total scores was examined using intra-class correlation (ICC). Agreement for individual items was tested with Cohen’s weighted kappa (κw).
South West of England.
Adults (n 177, 50·3 % women) with, or at high risk for, T2DM; mean age 55·8 (sd 8·6) years, mean BMI 34·4 (sd 7·3) kg/m2; participants were 91 % White British.
The UKDDQ showed excellent repeatability (ICC=0·90 (0·82, 0·94)). For individual items, κw ranged from 0·43 (‘savoury pastries’) to 0·87 (‘vegetables’). Total scores from the UKDDQ and food diaries compared well (ICC=0·54 (0·27, 0·70)). Agreement for individual items varied and was good for ‘alcohol’ (κw=0·71) and ‘breakfast cereals’ (κw=0·70), with no agreement for ‘vegetables’ (κw=0·08) or ‘savoury pastries’ (κw=0·09).
The UKDDQ is a new British dietary questionnaire with excellent repeatability. Comparisons with food diaries found agreements similar to those for international dietary questionnaires currently in use. It targets foods and habits important in diabetes prevention and management.