The shifting shelf task: a new, non-verbal measure for attentional set shifting.

Attentional set shifting is a core ingredient of cognition, allowing for fast adaptation to changes in the environment. How this skill compares between humans and other primates is not well known. We examined performance of 3- to 5-year-old children and chimpanzees on a new attentional set shifting task. We presented participants with two shelves holding the same set of four boxes. To choose the correct box on each shelf, one has to switch attention depending on which shelf one is currently presented with. Experiment 1 (forty-six 3- to 5-year olds, predominantly European White) established content validity, showing that the majority of errors were specific switching mistakes indicating failure to shift attention. Experiment 2 (one hundred and seventy-eight 3- to 6-year olds, predominantly European White) showed that older children made fewer mistakes, but if mistakes were made, a larger proportion were switching mistakes rather than 'random' errors. Experiment 3 (52 chimpanzees) established suitability of the task for non-human great apes and showed that chimpanzees' performance was comparable to the performance of 3- and 4-year olds, but worse than 5-year olds. These results suggest that chimpanzees and young children share attentional set shifting capacities, but that there are unique changes in the human lineage from 5 years of age.

Nanostructure of Edge Dislocations in a Smectic-C* Liquid Crystal.

We report on the first direct nanoscale imaging of elementary edge dislocations in a thermotropic smectic-C* liquid crystal with the Burgers vector equal to one smectic layer spacing d. We find two different types of dislocation profiles. In the dislocation of type A, the layers deformations lack mirror symmetry with respect to the plane perpendicular to the Burgers vector; the dislocation core size is on the order of d. In the dislocation of type S, the core is strongly anisotropic, extending along the Burgers vector over distances much larger (by a factor of 4) than d. The difference is attributed to a different orientation of the molecular tilt plane with respect to the dislocation's axis; the asymmetric layers distortions are observed when the molecular tilt plane is perpendicular to the axis and the split S core is observed when the molecules are tilted along the line.

Effectiveness of out-patient based acute heart failure care: a pilot randomised controlled trial.

OBJECTIVES: Acute heart failure (AHF) hospitalisation is associated with 10% mortality. Outpatient based management (OPM) of AHF appeared effective in observational studies. We conducted a pilot randomised controlled trial (RCT) comparing OPM with standard inpatient care (IPM). METHODS: We randomised patients with AHF, considered to need IV diuretic treatment for ≥2 days, to IPM or OPM. We recorded all-cause mortality, and the number of days alive and out-of-hospital (DAOH). Quality of life, mental well-being and Hope scores were assessed. Mean NHS cost savings and 95% central range (CR) were calculated from bootstrap analysis. Follow-up: 60 days. RESULTS: Eleven patients were randomised to IPM and 13 to OPM. There was no statistically significant difference in all-cause mortality during the index episode (1/11 vs 0/13) and up to 60 days follow-up (2/11 vs 2/13) [p = .86]. The OPM group accrued more DAOH {47 [36,51] vs 59 [41,60], p = .13}. Two patients randomised to IPM (vs 6 OPM) were readmitted [p = .31]. Hope scores increased more with OPM within 30 days but dropped to lower levels than IPM by 60 days. More out-patients had increased total well-being scores by 60 days (p = .04). OPM was associated with mean cost savings of £2658 (95% CR 460-4857) per patient. CONCLUSIONS: Patients with acute HF randomised to OPM accrued more days alive out of hospital (albeit not statistically significantly in this small pilot study). OPM is favoured by patients and carers and is associated with improved mental well-being and cost savings.

Smectic-C*alpha phase with two coexistent helical pitch values and a first-order smectic-C*alpha to smectic-C* transition.

Previous results from Kundu using dielectric relaxation have suggested a reentrant antiferroelectric-ferroelectric-antiferroelectric transition in the compound LN36. Our comprehensive studies of this compound using differential optical reflectivity, nonadiabatic scanning calorimetry, null transmission ellipsometry, and resonant x-ray diffraction show that in fact LN36 exhibits the usual phase sequence for chiral smectic liquid crystals: SmA*-SmC*alpha-SmC*-SmC*FI1-SmC*A . Moreover, the SmC*alpha-SmC* transition is a first-order transition, characterized by a discontinuous change in the helical pitch. At temperatures just above the SmC*alpha-SmC* transition, two different values for the helical pitch are simultaneously observed for the first time.

Distribution of fatty and fibrous plaques in young human coronary arteries.

We have correlated atheromatous plaque distribution with vessel geometry in coronary arteries from subjects dying of non-cardiovascular causes under 40 years of age. After standardised preparation, the area, and circumferential and longitudinal position of each plaque, were measured in the major coronary arteries. Of 41 sets of vessels, two were free of disease. In the remainder, total plaque area varied from 8 to 586 mm2. Half the cases showed fatty plaques only, and half showed both fatty and fibrous plaques. We analysed the distribution of plaques in those vessels affected only by very early fatty disease. In all vessels, plaques were concentrated proximally, but in the left anterior descending and circumflex branches the wall close to the flow-divider was spared. Circumferential distribution was also not random. In the right coronary artery, lesions were concentrated on the inner wall of the major curvature. In the left anterior descending branch, lesions spiralled anticlockwise from the orifice. We suggest that local mechanical factors may determine these patterns.

Dielectric relaxation behavior of a liquid crystal showing an unusual type of antiferroelectric-ferroelectric-antiferroelectric phase sequence.

The temperature and frequency dependent dielectric relaxation behavior of a liquid crystalline (S)-(+)-1-methylheptyl 4-[2-(4-alkoxyphenyl) thiophene-5-carbonylthiooxy] benzoate system is reported. Interesting successive antiferroelectric-ferroelectric-antiferroelectric (AF-FE-AF) phase transitions are observed in this system resembling the successive phase transitions observed in crystalline Rochelle salt. The smectic-C* (SmC*) to AF1 phase transition (around 103.0 degrees C) is first order in nature, predicted from the use of Orihara and Ishibashi theory. It is also found that a contribution of the ferroelectric SmC* phase ordering penetrates even in the antiferroelectric AF1 (SmC(*)(A)) and AF2 (SmC(*)(A)) phases very close to the SmC*-AF1 and SmC*-AF2 phase boundaries (critical regions). It is suggested that this type of mixing of AF and FE phases might cause surface induced ferroelectric- or ferroelectric-type ordering near the AF-FE phase transitions. A soft mode with Debye-type dispersion was observed in the SmA phase. The thermal behaviors of dielectric dispersion, absorption, and dielectric strength in different phases are also reported and discussed.

Interlayer structures of the chiral smectic liquid crystal phases revealed by resonant X-ray scattering.

The structures of the liquid crystalline chiral subphases exhibited by several materials containing either a selenium or sulphur atom have been investigated using a resonant x-ray scattering technique. This technique provides a unique structural probe for the ferroelectric, ferrielectric, antiferroelectric, and SmC(*)(alpha) phases. An analysis of the scattering features allows the structural models of the different subphases to be distinguished, in addition to providing a measurement of the helical pitch. This paper reports resonant scattering features in the antiferroelectric hexatic phase, the three- and four-layer intermediate phases, the antiferroelectric and ferroelectric phases and the SmC(*)(alpha) phase. The helicoidal pitch has been measured from the scattering peaks in the four-layer intermediate phase as well as in the antiferroelectric and ferroelectric phases. In the SmC(*)(alpha) phase, an investigation into the helical structure has revealed a pitch ranging from 5 to 54 layers in different materials. Further, a strong resonant scattering signal has been observed in mixtures of a selenium containing material with as much as 90% nonresonant material.

Pyroelectric properties of an antiferroelectric liquid crystal.

The effects of temperature and applied voltage on the pyroelectric properties of an antiferroelectric liquid crystal are given. It has been found that the pyroelectric signal depends strongly on the bias voltage across the sample. The pyroelectric signal behaviour is interpreted with the aid of spontaneous polarization data and good agreement is found between the results from the pyroelectric and polarization techniques. The spontaneous polarization of the sample exhibits the temperature- and field-induced `Devil's staircase' behaviour, as predicted by the Ising model.

If at first you don't succeed... Studies of ontogeny shed light on the cognitive demands of habitual tool use.

Many species use tools, but the mechanisms underpinning the behaviour differ between species and even among individuals within species, depending on the variants performed. When considering tool use 'as adaptation', an important first step is to understand the contribution made by fixed phenotypes as compared to flexible mechanisms, for instance learning. Social learning of tool use is sometimes inferred based on variation between populations of the same species but this approach is questionable. Specifically, alternative explanations cannot be ruled out because population differences are also driven by genetic and/or environmental factors. To better understand the mechanisms underlying routine but non-universal (i.e. habitual) tool use, we suggest focusing on the ontogeny of tool use and individual variation within populations. For example, if tool-using competence emerges late during ontogeny and improves with practice or varies with exposure to social cues, then a role for learning can be inferred. Experimental studies help identify the cognitive and developmental mechanisms used when tools are used to solve problems. The mechanisms underlying the route to tool-use acquisition have important consequences for our understanding of the accumulation in technological skill complexity over the life course of an individual, across generations and over evolutionary time.

Patients to people.

The ideas discussed in this paper are derived from a longitudinal study of student nurse socialization. The emergent views of a cohort of student nurses were explored by the researcher, over a period of 3 years, utilizing the approach referred to as grounded theory. 'Patients to people' represents a continuum of changing perceptions about those whom the students were nursing. It seemed that the cohort had to move along this continuum in order for them to be able to empathize with those they nursed. In the context of the students' changing perceptions, several things were of significance. For example, encounters with individuals who failed to demonstrate the passive and compliant attitude associated with 'typical patients', such as children, challenged the cohort's thinking about those they nursed. During their training the students matured as both nurses and adults and this was also important, as was their recognition of their own 'personhood'. The cohort's emergent views suggested that there was a reciprocity between the way they viewed themselves and the perceptions they held about those they nursed. Such findings are important to people involved in preparing individuals to enter the caring professions. However, it should be noted that the experiences described in this study represent those of 'traditionally' trained rather than of Project 2000 students. The names used to describe people involved in this research are pseudonyms.

Conducting a longitudinal study: an unsanitized account.

Sanitized accounts of research add little to the literature describing 'how' research is actually 'done'. This paper explores issues which emerged during the course of a longitudinal study which described the experiences of a cohort of 23 student nurses during their 3-year training for registration as general nurses in the United Kingdom. The approach used was that of grounded theory. The students' changing perspectives were collected by the researcher utilizing participant observation and unstructured interview in various clinical settings. In recognition of the fact that this is a 'reflexive' account it is written in the first person. Issues addressed include my 'immersion' in the research process, my relationship with the students, the challenges which derive from researching in a shifting context and the use of grounded theory within the context of the study. (All the names of students involved in the study are pseudonyms.)

Crossing the boundaries--experiences of neophyte nurses.

Boundaries exist that dictate socially acceptable degrees of bodily exposure and touch. Certain groups, for example nurses, appear to undertake emotionally charged work where they are called upon to cross these boundaries. This paper relates the experience of a student nurse cohort as they 'crossed the boundaries'. The students' views were collected by participant observation and interview, and analysed by employing grounded theory. Since the study was longitudinal the findings reflect how the neophytes' views changed with the passage of time. Early in their course students found giving intimate care stressful, while caring for those of the opposite sex created particular difficulties. Both male and female students developed coping strategies, for example 'ways of seeing' those they nursed. Students maintained that the nature of their work led others to view them in certain ways. In some instances female students might be seen as sexually available by men for whom they cared; however, with experience they dealt effectively with sexual advances. The cohort considered that wearing a uniform on the one hand protected and legitimized them in crossing boundaries, but on the other it signalled their occupation to others which on occasions was something they might wish to conceal. These findings provide insights into the notion of crossing social boundaries, an area which warrants further investigation, since it involves an important aspect of caring. (Names of students cited in this paper are pseudonyms.)

Measles vaccination in severely malnourished Sudanese children.

The clinical and serological responses to attenuated measles virus vaccine were compared in 35 severely malnourished and 35 well-nourished children. A third group of severely malnourished children, who received an injection of vitamin B12, served as controls. The children were observed for three weeks following vaccination. Paired sera were collected from each child before and after administration of the vaccine or vitamin B12 and measles antibody titres were estimated using HAI technique. The malnourished children who received measles vaccine developed higher fever of longer duration and had more lower respiratory tract disease than the other two groups but had fewer skin rashes than the well-nourished group. Sero-conversion rates were 96% had 92.6% in the malnourished and well-nourished vaccinated children, respectively. Antibody titres were lower in children who had marasmic/kwashiorkor than in the marasmic children.

Serum immunoglobulin levels in normal Sudanese children.

Immunoglobulin levels were estimated in 138 infants, of whom 33 were normal newborn and 105 were healthy infants one to 24 months of age. Most of the newborn were delivered after a normal pregnancy. In all the infants relatively high levels of cord IgM were found. Similarly, relatively high levels of IgA were found in cord blood in 72% of the subjects studied. Physiological hypogammaglobulinaemia was not found in the early months of life. Adult levels of IgM were developed by six months of age while 36% of the adult levels of IgA and 57% of the adult levels of IgG were reached by two years of age.

Landsat and limnologically derived water quality data: A perspective.

Fixed station sampling is the conventional method used to obtain data on the median water quality of reservoirs. A major source of uncertainty associated with this technique is that water quality at the fixed stations may not be representative of the ambient water quality in the reservoir at the time of sampling. This problem is particularly relevant for water quality variables such as chlorophyll, which have a markedly patchy spatial distribution. The use of Landsat reflectance data to estimate median chlorophyll concentrations in Roodeplaat Dam was investigated. A linear polynomial regression model for estimating chlorophyll concentrations from Landsat reflectance data, was firstly calibrated with chlorophyll concentration data obtained by sampling seven fixed stations on the reservoir at the time of the satellite overflight to produce an individual calibration. Secondly, the model was calibrated with a pooled set of sampled data obtained from five separate overflights, to obtain a generalised calibration.It was found that median chlorophyll concentrations determined from Landsat-derived data were similar to median chlorophyll concentrations estimated from fixed station data. However, the range of chlorophyll concentrations in the reservoir estimated from Landsat data was considerably larger than that estimated from fixed station data. Landsat derived estimates of chlorophyll concentrations have the added advantage of providing information on the spatial distribution of chlorophyll in the reservoir.

Clinical experience with endothelin receptor antagonists in chronic heart failure.

Both ET(A) selective and dual, ET(A/B), receptor antagonists have favourable short- and longer-term haemodynamic actions in patients with acute and chronic heart failure. Their effect on neurohumoral measures is not yet fully determined. Two moderately large, medium-duration studies have examined the effect of dual ET(A/B) receptor antagonists on clinical status, reaching conflicting conclusions. One large scale, long-term, morbidity mortality evaluation is underway with bosentan.

Proteinuria in Sudanese children.

One thousand, eight hundred and forty-six apparently healthy nursery and school children living in the Khartoum area and belonging to different socio-economic classes were studied. Nine hundred and thirty-seven were boys, 909 girls. Their ages ranged from three to 16 years. N-multistix strips were used to test for proteinuria and haematuria, the former being also checked by the sulphosalicylic acid test. Children with proteinuria of 1+ or more were further investigated by examining their urinary sediment for abnormal deposits and by testing for orthostatic proteinuria using day and night specimens of urine with specific gravity of 1.018 or more. Children who had no proteins on orthostatic testing were rescreened for proteinuria 10-14 days after the initial screening. The prevalence rate for proteinuria was 7.2% with no significant difference between boys and girls. In both sexes the prevalence rate increased significantly with age but was not influenced by the socio-economic status. Of the children with proteinuria, haematuria occurred in 27% and abnormal urinary deposits in 14.8%. Orthostatic testing showed a negative result for proteins in 44%, orthostatic proteinuria in 40%, of whom a third had either abnormal urinary sediments or haematuria, and continuous proteinuria in 15.6% of whom the majority had abnormal deposits.

The contractile state of cat and dog heart in relation to the interval between beats.

We induced atrioventricular dissociation and initiated ventricular pacing in intact dogs and isolated cat hearts. Left ventricular pressure, its time derivative (dP/t), and action potentials were recorded. When a test pulse was introduced at varying intervals after a period of steady pacing, an optimum contractile response was obtained at an average interval of 720 msec. A similar optimum interval was obtained after pacing at various frequencies and after paired pulse stimulation but was shortened to 560 msec after infusion of epinephrine. The magnitude of the optimum contractile response increased with an increase in the frequency of prior pacing which was accompanied by an increase in the time the cell membrane was depolarized. The optimum contractile response following paired pulse stimulation was greater than that following regular pacing, with the same number of stimuli per minute and the same time of membrane depolarization. The results are explicable in terms of intracellular calcium ion recirculation with separate compartments for release to and uptake from the contractile proteins. A negative feedback control of Ca2+ inflow to the cell by intracellular Ca2+ content is postulated to explain the effect of paired pulse stimulation and shortening of action potential duration following an increase in regular pacing frequency.

Fetal immune response following maternal diphtheria during early pregnancy.

A pregnant Sudanese woman contracted pharyngeal diphtheria during the first trimester of gestation. She had a severe diphtheritic toxaemia and paralysis of all four limbs but made a full recovery from these manifestations. Pregnancy, apart from vaginal bleeding, was not interrupted. At term she was delivered of a female baby who was physically normal but had a very high level of IgA in cord blood. Diphtheria in adults is a rare disease and the occurrence of diphtheria in a pregnant woman has not, as yet, been reported. Accordingly it is not known how fetal growth and development progress in the presence of diphtheria toxin in the maternal circulation. Similarly the effects on fetal immune responses of an acute maternal infection like diphtheria occurring in early pregnancy are not known.