7,119 research outputs found
East salt sparingly - sprinkle, don\u27t shake!
The salt-blood pressure hypothesis states that an excessive salt intake leads to an increase in blood pressure in genetically susceptible persons and, if high intake is maintained long term, ultimately leads to sustained hypertension. It is estimated that about 3.3 million South Africans (12.6% and 16.3% of adult men and women, respectively) are hypertensive. However, not all subjects within a particular population respond equally to exposure to high-salt diets. Methods to identify those who are \u27salt sensitive\u27 remain in the research domain; therefore a population approach to the restriction of dietary salt intake is warranted. The message to \u27eat salt sparingly\u27 will not interfere with the current nutritional and legal requirements regarding iodation of table salt. A salt intake as low as 5 g per day would provide an adequate amount of iodine, provided the salt is sufficiently iodated. Dietary factors other than sodium which have been shown to influence blood pressure include potassium, magnesium, calcium and alcohol. The \u27Dietary Approaches to Stop Hypertension\u27 (DASH) randomised controlled trial found that subjects fed a diet rich in fruit and vegetables for 8 weeks significantly reduced both systolic and diastolic blood pressure, compared with subjects on a typical American control diet. A \u27combination\u27 diet, rich in fruit, vegetables and low-fat dairy products, and with a reduced saturated and total fat intake, resulted in an even greater reduction in blood pressure. Translated into a practical diet, this information suggests a daily diet that includes large amounts of fruit and vegetables, a moderate intake of low-fat dairy products, lean meat and chicken, and a prudent alcohol intake. Salt should be used sparingly, if at all, at the table and in the preparation of meals, and the intake of processed foods high in salt should be limited. This would result in a reduction in intake from an average of around 9 g salt to about 6 g salt per day, which is the current USA recommendation. These blood pressure-related recommendations incorporate many of the various foodbased dietary guidelines, emphasising that the recommendations are congruent and mutually substantiative
Performance of three-photon PET imaging: Monte Carlo simulations
We have recently introduced the idea of making use of three-photon positron
annihilations in positron emission tomography. In this paper the basic
characteristics of the three-gamma imaging in PET are studied by means of Monte
Carlo simulations and analytical computations. Two typical configurations of
human and small animal scanners are considered. Three-photon imaging requires
high energy resolution detectors. Parameters currently attainable by CdZnTe
semiconductor detectors, the technology of choice for the future development of
radiation imaging, are assumed. Spatial resolution is calculated as a function
of detector energy resolution and size, position in the field of view, scanner
size, and the energies of the three gamma annihilation photons. Possible ways
to improve the spatial resolution obtained for nominal parameters: 1.5 cm and
3.2 mm FWHM for human and small animal scanners, respectively, are indicated.
Counting rates of true and random three-photon events for typical human and
small animal scanning configurations are assessed. A simple formula for minimum
size of lesions detectable in the three-gamma based images is derived.
Depending on the contrast and total number of registered counts, lesions of a
few mm size for human and sub mm for small animal scanners can be detected
Do red deer stags (Cervus elaphus) use roar fundamental frequency (F0) to assess rivals?
It is well established that in humans, male voices are disproportionately lower pitched than female voices, and recent studies suggest that this dimorphism in fundamental frequency (F0) results from both intrasexual (male competition) and intersexual (female mate choice) selection for lower pitched voices in men. However, comparative investigations indicate that sexual dimorphism in F0 is not universal in terrestrial mammals. In the highly polygynous and sexually dimorphic Scottish red deer Cervus elaphus scoticus, more successful males give sexually-selected calls (roars) with higher minimum F0s, suggesting that high, rather than low F0s advertise quality in this subspecies. While playback experiments demonstrated that oestrous females prefer higher pitched roars, the potential role of roar F0 in male competition remains untested. Here we examined the response of rutting red deer stags to playbacks of re-synthesized male roars with different median F0s. Our results show that stags’ responses (latencies and durations of attention, vocal and approach responses) were not affected by the F0 of the roar. This suggests that intrasexual selection is unlikely to strongly influence the evolution of roar F0 in Scottish red deer stags, and illustrates how the F0 of terrestrial mammal vocal sexual signals may be subject to different selection pressures across species. Further investigations on species characterized by different F0 profiles are needed to provide a comparative background for evolutionary interpretations of sex differences in mammalian vocalizations
Aging with Elevated Autistic Traits: Cognitive Functioning Among Older Adults with the Broad Autism Phenotype
Background: Little is known about the impact of aging with autism spectrum disorder (ASD) on cognition. As a first step in addressing this gap in our knowledge, the current study examined cognitive functioning among older adults with elevated, but subclinical levels of autistic traits (i.e., the Broad Autism Phenotype; BAP) compared to older adults without the BAP.
Method: Forty older adults (aged 60-91, M=73 years) were recruited and classified as meeting criteria for the BAP (n=20) or not (control older adults, COA; n=20). Different components of executive function as well as episodic memory were measured using standardized performance-based neuropsychological assessments in addition to a self-report questionnaire of executive function difficulties.
Results: Despite no differences in age, sex ratio, educational history or IQ, the BAP group demonstrated poorer performance on measures of executive function and episodic memory compared to the COA group. The BAP group also self-reported more executive function difficulties in everyday settings. Moreover, differences in working memory and attentional shifting were maintained after accounting for the influences of IQ and both depression and anxiety symptoms.
Conclusions: These findings suggest that aging with the BAP confers additional risk to cognitive function for older adults. As the BAP forms a bridge in the continuum from typical to atypical levels of autistic traits, these findings suggest that individuals with ASD might also incur cognitive costs as they age into older adulthood
Social Support and Links to Quality of Life Among Middle and Older Age Autistic Adults
Social support has a positive impact on quality of life (QoL) in neurotypical older adults and young autistic adults, but the association for older autistic adults is unclear. Autistic adults (n=388; mean age=40-83 years) were recruited via Simons Powering Autism Research for Knowledge research match. Participants completed questionnaires online querying demographic information, depression and anxiety symptomatology, QoL (Physical, Psychological, Social, Environmental, Autism-specific) and social support (instrumental, subjective and social interactions). Regression analyses examined whether different aspects of social support explained the variance in each domain of QoL. A significant proportion of the variance (36-58%) in QoL was explained. Subjective social support significantly contributed to the models for all aspects of QoL; Physical and Psychological QoL were also explained by social interactions, whereas Social, Environmental and Autism-specific QoL were additionally explained by instrumental support. Social support is an important contributor to the QoL of middle-aged and older autistic adults, after accounting for demographic factors and depression. Further studies are required to understand whether age-related changes in social support and QoL are the same for autistic as non-autistic older adults in order to identify and implement appropriate support
Zero range potential for particles interacting via Coulomb potential: application to electron positron annihilation
The zero range potential is constructed for a system of two particles
interacting via the Coulomb potential. The singular part of the asymptote of
the wave function at the origin which is caused by the common effect of the
zero range potential singularity and of the Coulomb potential is explicitly
calculated by using the Lippmann-Schwinger type integral equation. The singular
pseudo potential is constructed from the requirement that it enforces the
solution to the Coulomb Schr\"odinger equation to possess the calculated
asymptotic behavior at the origin. This pseudo potential is then used for
constructing a model of the imaginary absorbing potential which allows to treat
the annihilation process in positron electron collisions on the basis of the
non relativistic Schr\"odinger equation. The functional form of the pseudo
potential constructed in this paper is analogous to the well known
Fermi-Breit-Huang pseudo potential. The generalization of the optical theorem
on the case of the imaginary absorbing potential in presence of the Coulomb
force is given in terms of the partial wave series
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Grass silage particle size when fed with or without maize silage alters performance, reticular pH and metabolism of Holstein-Friesian dairy cows
The particle size of the forage has been proposed as a key factor to ensure a healthy rumen function and maintain dairy cow performance, but little work has been conducted on ryegrass silage (GS). To determine the effect of chop length of GS and GS:maize silage (MS) ratio on the performance, reticular pH, metabolism and eating behaviour of dairy cows, 16 multiparous Holstein-Friesian cows were used in a 4×4 Latin square design with four periods each of 28-days duration. Ryegrass was harvested and ensiled at two mean chop lengths (short and long) and included at two ratios of GS:MS (100:0 or 40:60 dry matter (DM) basis). The forages were fed in mixed rations to produce four isonitrogenous and isoenergetic diets: long chop GS, short chop GS, long chop GS and MS and short chop GS and MS. The DM intake (DMI) was 3.2 kg/day higher (P<0.001) when cows were fed the MS than the GS-based diets. The short chop length GS also resulted in a 0.9 kg/day DM higher (P<0.05) DMI compared with the long chop length. When fed the GS:MS-based diets, cows produced 2.4 kg/day more (P<0.001) milk than when fed diets containing GS only. There was an interaction (P<0.05) between chop length and forage ratio for milk yield, with a short chop length GS increasing yield in cows fed GS but not MS-based diets. An interaction for DM and organic matter digestibility was also observed (P<0.05), where a short chop length GS increased digestibility in cows when fed the GS-based diets but had little effect when fed the MS-based diet. When fed the MS-based diets, cows spent longer at reticular pH levels below pH 6.2 and pH 6.5 (P<0.01), but chop length had little effect. Cows when fed the MS-based diets had a higher (P<0.05) milk fat concentration of C18 : 2n-6 and total polyunsaturated fatty acids compared with when fed the GS only diets. In conclusion, GS chop length had little effect on reticular pH, but a longer chop length reduced DMI and milk yield but had little effect on milk fat yield. Including MS reduced reticular pH, but increased DMI and milk performance irrespective of the GS chop length
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