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Cognitive impairment is a core feature of psychotic disorders, but the profile of impairment across adulthood, particularly in African-American populations, remains unclear.
Using cross-sectional data from a case–control study of African-American adults with affective (n = 59) and nonaffective (n = 68) psychotic disorders, we examined cognitive functioning between early and middle adulthood (ages 20–60) on measures of general cognitive ability, language, abstract reasoning, processing speed, executive function, verbal memory, and working memory.
Both affective and nonaffective psychosis patients showed substantial and widespread cognitive impairments. However, comparison of cognitive functioning between controls and psychosis groups throughout early (ages 20–40) and middle (ages 40–60) adulthood also revealed age-associated group differences. During early adulthood, the nonaffective psychosis group showed increasing impairments with age on measures of general cognitive ability and executive function, while the affective psychosis group showed increasing impairment on a measure of language ability. Impairments on other cognitive measures remained mostly stable, although decreasing impairments on measures of processing speed, memory and working memory were also observed.
These findings suggest similarities, but also differences in the profile of cognitive dysfunction in adults with affective and nonaffective psychotic disorders. Both affective and nonaffective patients showed substantial and relatively stable impairments across adulthood. The nonaffective group also showed increasing impairments with age in general and executive functions, and the affective group showed an increasing impairment in verbal functions, possibly suggesting different underlying etiopathogenic mechanisms.
The earliest phases of star formation are characterised by intense mass accretion from the circumstellar disk to the central star. One group of young stellar objects, the FU Orionis-type stars exhibit accretion rate peaks accompanied by bright eruptions. The occurance of these outbursts might solve the luminosity problem of protostars, play a key role in accumulating the final star mass, and have a significant effect on the parameters of the envelope and the disk. In the framework of the Structured Accretion Disks ERC project, we are conducting a systematic investigation of these sources with millimeter interferometry to examine whether they represent normal young stars in exceptional times or they are unusual objects. Our results show that FU Orionis-type stars can be similar to both Class I and Class II systems and may be in a special evolutionary phase between the two classes with their infall-driven episodic eruptions being the main driving force of the transition.
In battery systems, a solid electrolyte interphase (SEI) is formed through electrolyte reaction on an electrode surface. The formation of SEI can have both positive and negative effects on electrochemistry. The initial formation of the layer protects the electrode from further reactivity, which can improve both shelf and cycle life. However, if the layer continues to form, it can impede charge transfer, which increases cell resistance and limits cycle life. The role of SEI is particularly important when studying conversion electrodes, since phase transformations which unveil new electroactive surfaces during reduction/oxidation can facilitate electrolyte decomposition. This manuscript highlights recent developments in the understanding and control of SEI formation for magnetite (Fe3O4) conversion electrodes through electrolyte and electrode modification.
Atomic force microscopy is employed to study the structural changes in the morphology and physical characteristics of asphaltene aggregates as a function of temperature. The exotic fractal structure obtained by evaporation-driven asphaltene aggregates shows an interesting dynamics for a large range of temperatures from 25°C to 80°C. The changes in the topography, surface potential and adhesion are unnoticeable until 70°C. However, a significant change in the dynamics and material properties is displayed in the range of 70°C - 80°C, during which the aspahltene aggregates acquire ‘liquid-like’ mobility and fuse together. This behaviour is attributed to the transition from the pure amorphous phase to a crystalline liquid phase which occurs at approximately 70°C as shown by using Differential Scanning Calorimetry (DSC). Additionally, the charged nature of asphaltenes and bitumen is also explored using kelvin probe microscopy. Such observations can lead to the development of a rational approach to the fundamental understanding of asphaltene aggregation dynamics and may help in devising novel techniques for the handling and separation of asphaltene aggregates using dielectrophoretic methods.
Understanding the growth dynamics of fine roots and their contribution to soil organic carbon and nutrient pools is crucial for estimating ecosystem carbon and nutrient cycling and how these are influenced by climate change. Rubber is cultivated in more than 10 million hectare globally and the area under rubber cultivation is fast expanding due to socio-economic reasons, apart from the importance given to this species for eco-restoration of degraded lands. An experiment was conducted to quantify fine root production, fine root turnover and carbon and nutrient cycling through fine roots in rubber plantations with different soil nutrient status and rainfall pattern. Fine root production was estimated by sequential coring and ingrowth core methods. Fine root decomposition was determined by the litter bag technique. Carbon and nutrient contents in fine roots were determined and their turnover was computed. Fine root biomass in the top 0–7.5-cm soil layer showed significant seasonal fluctuation and the fluctuations were particularly wide during the transition period from the dry season to the rainy season. Fine root production estimated by the different methods was significantly higher at the lower fertility site and during the higher soil moisture stress year. Fine root turnover ranged from 1.04 to 2.29 year−1. Root carbon and nutrient status showed seasonal variation and lower status was observed during the rainy season. The annual recycling of C, N, P, K, Ca and Mg through fine roots ranged from 590 to 1758, 30 to 85, 3 to 12, 13 to 31, 11 to 35 and 6 to 13 kg ha−1, respectively. Substantial quantities of carbon and nutrients were recycled annually in rubber plantations through fine roots. When soil moisture and nutrient stress were more severe, fine root production, turnover and carbon and nutrient recycling through fine roots were higher.
The ability to efficiently harvest heat as a source of sustainable energy would make a significant contribution to reducing our current reliance on fossil fuels. Waste heat sources, such as those produced in industrial processes or through geothermal activity, are extensive, often continuous, and at present severely underutilised. Thermoelectrochemical cells offer an alternative design to the traditional semiconductor-based thermoelectric devices and offer thepromise of continuous and cheap operation at moderate temperatures, low maintenance and with no carbon emissions. They utilise two electrodes, held at different temperatures, separated by an electrolyte containing a redox couple. It is the temperature dependence of the electrochemical redox potential that generates the potential difference across the device as a result of the appliedtemperature difference. The magnitude of this redox potential temperature dependence is given by the Seebeck coefficient, Se. Until recently, research into thermoelectrochemical cells had primarily focused on aqueous media, predominantly with the Fe(CN)63-/4- redox couple. However, the good thermal and electrochemical stability, non-volatility and non-flammability ofmany ionic liquids make them promising alternative electrolytes for these devices. The use of ionic liquid (IL) electrolytes offers potential advantages that include increased thermoelectrochemical device efficiencies and lifetimes and the ability to utilise low temperature (often “waste”) heat sources in the 100 – 200 °C temperature range. Here we discuss our research into the use of the Fe(CN)63-/4- redox couple in protic IL electrolytes, with different amounts of added water, in a thermoelectrochemical device with platinum and single walled carbon nanotube (SWNT) electrodes.
In this work we propose the Bardeen-Petterson effect as the precession mechanism of the jet precession in NGC 1275. To check if this is true we have estimated the angular momentum ratio and the aligment timescale predict by the theory and compared with the numerical results presented in the literature. We were able to explain the precession period assuming an accretion disk with column surface density in the form of a power law with exponent 0.6 < s < 0.7 and a black hole rotation with a spin of 0.23 < a∗<0.4.
Several galaxy clusters are known to present multiple and misaligned pairs of cavities seen in X-rays, as well as twisted kiloparsec-scale jets at radio wavelengths. It suggests that the AGN precessing jets play a role in the formation of the misaligned bubbles. Also, X-ray spectra reveal that typically these systems are also able to supress cooling flows, predicted theoretically. The absence of cooling flows in galaxy clusters has been a mistery for many years since numerical simulations and analytical studies suggest that AGN jets are highly energetic, but are unable to redistribute it at all directions. We performed 3D hydrodynamical simulations of the interaction between a precessing AGN jet and the warm intracluster medium plasma, in which dynamics is coupled to a NFW dark matter gravitational potential. Radiative cooling has been taken into account and the cooling flow problem was studied. We found that precession is responsible for multiple pairs of bubbles, as observed. The misaligned bubbles rise up to scales of tens of kiloparsecs, where the thermal energy released by the jets are redistributed. After ~150 Myrs, the temperature of the gas within the cavities is kept of order of ~107 K, while the denser plasma of the intracluster medium at the central regions reaches T ~ 105 K. The existence of multiple bubbles, at diferent directions, results in an integrated temperature along the line of sight much larger than the simulations of non-precessing jets. This result is in agreement with the observations. The simulations reveal that the cooling flows cessed ~50–70 Myr after the AGN jets are started.
In combinatorial optimization, a popular approach to NP-hard problems is the design of approximation algorithms. These algorithms typically run in polynomial time and are guaranteed to produce a solution which is within a known multiplicative factor of optimal. Unfortunately, the known factor is often known to be large in pathological instances. Conventional wisdom holds that, in practice, approximation algorithms will produce solutions closer to optimal than their proven guarantees. In this paper, we use the rigorous-analysis-of-heuristics framework to investigate this conventional wisdom.
We analyse the performance of three related approximation algorithms for the uncapacitated facility location problem (from Jain, Mahdian, Markakis, Saberi and Vazirani (2003) and Mahdian, Ye and Zhang (2002)) when each is applied to an instances created by placing n points uniformly at random in the unit square. We find that, with high probability, these 3 algorithms do not find asymptotically optimal solutions, and, also with high probability, a simple plane partitioning heuristic does find an asymptotically optimal solution.
We study a dynamically evolving random graph which adds vertices and edges using preferential attachment and is ‘attacked by an adversary’. At time t, we add a new vertex xt and m random edges incident with xt, where m is constant. The neighbours of xt are chosen with probability proportional to degree. After adding the edges, the adversary is allowed to delete vertices. The only constraint on the adversarial deletions is that the total number of vertices deleted by time n must be no larger than δn, where δ is a constant. We show that if δ is sufficiently small and m is sufficiently large then with high probability at time n the generated graph has a component of size at least n/30.
The Charity Commission website lists in excess of 100 equine charities (Charity Commission, 2003) and this figure does not include those whose annual income is under £1,000. The size and nature of equine related charities varies enormously. In 2002 the top 6 equine charities (listed below) had a combined income of £40m and were responsible for rescuing approximately 600 horses, ponies and donkeys (Peplow, 2003).
International League for the Protection of Horses
Home of Rest for Horses
The Donkey Sanctuary
Horse and Pony Protection Association
Whilst these larger charities have grown organically over the years, many smaller charities are failing to survive and are in some situations having to be ‘rescued’ themselves by their larger counterparts. The public, consisting of present and potential donors, are offered a vast choice of charities to support. Philanthropic behaviour has at best stagnated in recent years (Sargeant & Lee, 2002).
The equine passport legislation is a comparatively new scheme that requires all horses to have a passport by 28th February 2005 (Defra, 2004). The equine passport is thought to have had a major impact on the industry in the United Kingdom, however the extent of this is, as yet, unknown due to the lack of current research. The UK Government hopes that the passport scheme will monitor horses that have been treated with medication and guarantee that they are not slaughtered for human consumption (Frank, 2003, Defra, 2004). Whilst the scheme originated from European food safety legislation (Ellis, 2003), the UK Government believes that there are other benefits attached to the equine passport, such as gaining comprehensive records about the equine population in the UK, which is crucial information required for epidemiological reasons (Mellor et al., 1999). The information will provide a denominator for the assessment of disease rates, and which areas of the country may be under threat.
Herbal medicines are used in the horse to treat disease and help sustain optimum health within the body (Fleming, 2002). The popularity of complementary alternative medicines (CAM) in humans, such as herbal medicine, is continually growing across the United Kingdom (Ernst and White, 2000) and worldwide (Maclennon et al., 2003). The ability of alternative medicine to provide relief of specific symptoms to ailments is thought to be a major factor contributing to the rise of CAM (Pascoe, 2002). Much research has been conducted assessing the market for herbal products in humans, but little has been done on equine herbal products. Research by Astin (1998) suggests that a significant predictor of CAM use in humans is the buyers’ level of education; at least 50 % of respondents using CAM had degrees. A higher level of education allowed buyers to gain an understanding of the use of CAM and how it works.
To describe the selection and modification of an appropriate diet score to assess diet quality in early old age.
Design and setting
Cross-sectional analyses of the Boyd Orr cohort – a long-term follow-up of men and women whose families took part in a survey of diet and health in pre-war Britain. Dietary data were obtained from a 113-item food-frequency questionnaire. A nine-item Healthy Diet Indicator (HDI) developed by Huijbregts and colleagues was identified from the literature and modified because some dietary variables were unavailable and to accord more closely with recommendations of the UK Committee on Medical Aspects of Food Policy.
In total, 1475 traced, surviving cohort members aged 60 years and over.
Modification resulted in a 12-item Healthy Diet Score (HDS). We found that about half the variation in the HDS was explained by variation in the HDI (r = 0.71). There was, however, little misclassification of subjects (<10%) into extreme thirds of the distribution by the HDS compared with the HDI. Items of the score most strongly correlated with overall score were saturated fat (r = −0.57), red meat (r = −0.46), dietary fibre (r = 0.58), fruit and vegetables (r = 0.54) and percentage energy from carbohydrates (r = 0.51). Modifying existing items had greater impact on agreement between HDI and HDS than the addition of new items.
The selection and modification of diet scores is more complicated than often assumed. Furthermore, modest changes to an existing score can produce a score that is different from the original, and although it was not possible to test this issue, it may no longer predict subsequent health experience.