1,037 research outputs found
The Effects Of Phosphatidylserine On Reaction Time And Cognitive Function Following An Exercise Stress
Phosphatidylserine (PS) is an endogenously occurring phospholipid that has been shown to have cognition and mood enhancing properties in humans, possibly through its role as an enzyme co-factor in cellular signal transduction. Specifically, PS has been identified as activator of classical isoforms of protein kinase C, an enzyme known to be involved in the growth and differentiation of neural cells, and is therefore thought to play a role in the protection of neurons. The purpose of this study was to examine the effects of supplementation with PS and caffeine on measures of cognition, reaction time and mood prior to and following an exercise stress. Twenty, healthy, resistance trained males (17) and females (3) (mean ± SD; age: 22.75 ± 3.27 yrs; height: 177.03 ± 8.44cm; weight: 78.98 ± 11.24kg; body fat%: 14.28 ± 6.6), volunteered to participate in this randomized, double-blind, placebo-controlled study. Participants were assigned to a PS group (400mg/day PS; 100mg/day caffeine, N=9) or PL (16g/day Carbs, N=11) delivered in the form of 4 candy chews identical in size, shape and color. Subjects performed an acute bout of full body resistance exercise, prior to (T1) and following 14 days of supplementation (T2). Measures of reaction time (Dynavision® D2 Visuomotor Training Device), cognition (Serial Subtraction Test, SST), and mood (Profile of Mood States, POMS) were assessed immediately before and following resistance exercise in both T1 and T2. Data was analyzed using two-way ANCOVA and repeated measures ANOVA. Supplementation with 400mg PS and 100mg caffeine did not have a significant impact upon measures of reaction time or cognition between groups at baseline or following acute resistance exercise. However, there was a non-significant trend to the attenuation of fatigue iv between groups, following acute resistance exercise (p = 0.071). Interestingly, our data suggests that acute resistance exercise alone may improve cognitive function. Although more research is necessary regarding optimal dosage and supplementation duration, the current findings suggest that supplementation 400mg/day PS with 100mg/day caffeine may attenuate fatigue following acute resistance exercise. It is possible that the lack of significance may be the result of both an inhibition of the PS activated pathway and a withdrawal effect from caffeine
Interface morphology and Dzyaloshinskii-Moriya interaction in Pt/Co thin films
The interfacial morphology and the Dzyaloshinskii-Moriya interaction (DMI) have been investigated in thin films of perpendicularly-magnetised epitaxial Pt(30 A)/Co(7 A)/Pt(10 A) and Pt(30 A)/Co(7, 9, 11 A)/Ir20Mn80(20, 50 A). In Pt/Co/Pt, altering the substrate temperature during deposition of the top Co/Pt bilayer in the range of 100 C to 300 C formed a peak in total interfacial disorder with deposition temperature of 3.3 A at around 250 C. The coercivity increased from 230 +/- 60 Oe to 400 +/- 60 Oe whilst the anisotropy and saturation magnetisation stayed constant at 15.0 +/- 0.3 kOe and 90 +/- 10 microemu, respectively, when the substrate temperature at deposition was reduced in value. In contrast, the anisotropy increased with deposition temperature if either the substrate temperature was increased, or the deposition temperature of only the top Pt layer was varied, though not both simultaneously.
The bubble domain expansion technique was used to measure domain wall velocity with applied magnetic fields in various in-plane (IP) and out-of-plane (OOP) configurations. Of the three prominent creep models used, it was found that the most basic model fitted best. A moderate linear correlation was seen between DMI and the difference in disorder between the top and bottom Co interfaces, indicating that as the disorder in one interface increases, its contribution to DMI decreases, allowing the relative interface disorders to dictate the strength, and even sign, of the net DMI. The net DMI increased with increasing deposition temperature, also, showing that such a growth parameter can be used to fine-tune the DMI.
Using Pt/Co/Ir20Mn80 samples, the growth temperature and working pressure were optimised for DMI measurements. Samples with 50 A of IrMn, with exchange bias strengths up to 1000 Oe, showed a high density of small, rough domains forming during magnetisation reversal. Samples with 20 A of IrMn, so without exchange bias, produced well-formed bubble domains for Co thicknesses below 9 A, with a Voronoi-like network seen in an 11 A sample. Bubble domain expansion showed severely skewed velocity against IP field graphs, with behaviour at higher fields not predicted by current models, giving DMI constant values between -0.6 and -1.0 mJ/m^2
The Effect of Half Time Sports Drink Ingestion on Subsequent Half Performance in U16 Female Soccer Players during Consecutive Matches
The purpose of this study was to evaluate the effect of halftime sports drink ingestion on second half performance in U16 female soccer players using GPS technology. While 12 players initially took part in the study, only six players were included in the analysis (age, 15.97±0.45 years; height, 159.62±5.35cm; body mass, 54.87±4.25; body mass index, 21.58±2.10 kg·m-2). In a double-blinded study design, twelve U16 female soccer players were randomly assigned to two groups (carbohydrate- sports drink or placebo). During half time of each game, players were provided with 500 ml of a drink and consumed the same liquid at halftime during all games of the first weekend, with the opposite beverage consumed during friendly matches on a subsequent weekend. Absolute running distance, distance covered per minute, distance covered in each of six velocity categories, and game load were tracked using GPS/HR during 2 games on 2 consecutive weekends. Distance covered at walking speed was significantly higher for the sports drink group (F = 11.026; p= .007), specifically in the second half. Consequently, sports drink influenced distance covered at low-intensity running speed (F= 7.275; p= .021), while placebo group decreased distance covered in the second half comparing to first half, supplementation group increased from first to second half. There were no significant changes between groups for any other speed velocities variables. Despite the lack of significance found between groups, this study found a decrease in performance from first half to second half at fast running (F = 6.807; p= 0.024), and high intensity running speed (F = 19.648; p≤.001). No significant results were found at distance covered per minute. This study conclude that sports drink ingestion have no benefit in preventing deterioration in performance, and overall sports drink did not influence youth female soccer players performance throughout a weekend of game
‘Savage times come again’ : Morel, Wells, and the African Soldier, c.1885-1920
The African soldier trained in western combat was a figure of fear and revulsion in the late nineteenth and early twentieth centuries. My article examines representations of African soldiers in nonfictional writings by E.D. Morel about the Congo Free State (1885-1908), the same author’s reportage on African troops in post-First World War Germany, and H.G. Wells’s speculative fiction When the Sleeper Wakes (1899, 1910). In each text racist and anti-colonialist discourses converge in representing the African soldier as the henchman of corrupt imperialism. His alleged propensity for taboo crimes of cannibalism and rape are conceived as threats to white safety and indeed supremacy. By tracing Wells’s connections to the Congo reform campaign and situating his novel between two phases of Morel’s writing career, I interpret When the Sleeper Wakes as neither simply a reflection of past events in Africa or as a prediction of future ones in Europe. It is rather a transcultural text which reveals the impact of European culture upon the ‘Congo atrocities’, and the inscription of this controversy upon European popular cultural forms and social debates
The Effectiveness of Embedded Values Analysis Modules in Computer Science Education: An Empirical Study
Embedding ethics modules within computer science courses has become a popular
response to the growing recognition that CS programs need to better equip their
students to navigate the ethical dimensions of computing technologies like AI,
machine learning, and big data analytics. However, the popularity of this
approach has outpaced the evidence of its positive outcomes. To help close that
gap, this empirical study reports positive results from Northeastern's program
that embeds values analysis modules into CS courses. The resulting data suggest
that such modules have a positive effect on students' moral attitudes and that
students leave the modules believing they are more prepared to navigate the
ethical dimensions they will likely face in their eventual careers.
Importantly, these gains were accomplished at an institution without a
philosophy doctoral program, suggesting this strategy can be effectively
employed by a wider range of institutions than many have thought
Structural neuroimaging in preclinical dementia: From microstructural deficits and grey matter atrophy to macroscale connectomic changes.
The last decade has witnessed a proliferation of neuroimaging studies characterising brain changes associated with Alzheimer's disease (AD), where both widespread atrophy and 'signature' brain regions have been implicated. In parallel, a prolonged latency period has been established in AD, with abnormal cerebral changes beginning many years before symptom onset. This raises the possibility of early therapeutic intervention, even before symptoms, when treatments could have the greatest effect on disease-course modification. Two important prerequisites of this endeavour are (1) accurate characterisation or risk stratification and (2) monitoring of progression using neuroimaging outcomes as a surrogate biomarker in those without symptoms but who will develop AD, here referred to as preclinical AD. Structural neuroimaging modalities have been used to identify brain changes related to risk factors for AD, such as familial genetic mutations, risk genes (for example apolipoprotein epsilon-4 allele), and/or family history. In this review, we summarise structural imaging findings in preclinical AD. Overall, the literature suggests early vulnerability in characteristic regions, such as the medial temporal lobe structures and the precuneus, as well as white matter tracts in the fornix, cingulum and corpus callosum. We conclude that while structural markers are promising, more research and validation studies are needed before future secondary prevention trials can adopt structural imaging biomarkers as either stratification or surrogate biomarkers.This study was supported by the National Institute for Health Research (NIHR, RG64473), Cambridge Biomedical Research Centre and Biomedical Research Unit in Dementia, and the Alzheimer's Society. Elijah Mak was in the receipt of the Gates Cambridge studentship
Structural neuroimaging in preclinical dementia: From microstructural deficits and grey matter atrophy to macroscale connectomic changes.
The last decade has witnessed a proliferation of neuroimaging studies characterising brain changes associated with Alzheimer's disease (AD), where both widespread atrophy and 'signature' brain regions have been implicated. In parallel, a prolonged latency period has been established in AD, with abnormal cerebral changes beginning many years before symptom onset. This raises the possibility of early therapeutic intervention, even before symptoms, when treatments could have the greatest effect on disease-course modification. Two important prerequisites of this endeavour are (1) accurate characterisation or risk stratification and (2) monitoring of progression using neuroimaging outcomes as a surrogate biomarker in those without symptoms but who will develop AD, here referred to as preclinical AD. Structural neuroimaging modalities have been used to identify brain changes related to risk factors for AD, such as familial genetic mutations, risk genes (for example apolipoprotein epsilon-4 allele), and/or family history. In this review, we summarise structural imaging findings in preclinical AD. Overall, the literature suggests early vulnerability in characteristic regions, such as the medial temporal lobe structures and the precuneus, as well as white matter tracts in the fornix, cingulum and corpus callosum. We conclude that while structural markers are promising, more research and validation studies are needed before future secondary prevention trials can adopt structural imaging biomarkers as either stratification or surrogate biomarkers.This study was supported by the National Institute for Health Research (NIHR, RG64473), Cambridge Biomedical Research Centre and Biomedical Research Unit in Dementia, and the Alzheimer's Society. Elijah Mak was in the receipt of the Gates Cambridge studentship
Functional neuroimaging findings in healthy middle-aged adults at risk of Alzheimer's disease.
It is well established that the neurodegenerative process of Alzheimer's disease (AD) begins many years before symptom onset. This preclinical phase provides a crucial time-window for therapeutic intervention, though this requires biomarkers that could evaluate the efficacy of future disease-modification treatments in asymptomatic individuals. The last decade has witnessed a proliferation of studies characterizing the temporal sequence of the earliest functional and structural brain imaging changes in AD. These efforts have focused on studying individuals who are highly vulnerable to develop AD, such as those with familial genetic mutations, susceptibility genes (i.e. apolipoprotein epsilon-4 allele), and/or a positive family history of AD. In this paper, we review the rapidly growing literature of functional imaging changes in cognitively intact individuals who are middle-aged: positron emission tomography (PET) studies of amyloid deposition, glucose metabolism, as well as arterial spin labeling (ASL), task-dependent, resting-state functional magnetic resonance imaging (fMRI) and magnetic resonance spectroscopy (MRS) studies. The prevailing evidence points to early brain functional changes in the relative absence of cognitive impairment and structural atrophy, although there is marked variability in the directionality of the changes, which could, in turn, be related to antagonistic pleiotropy early in life. A common theme across studies relates to the spatial extent of these changes, most of which overlap with brain regions that are implicated in established AD. Notwithstanding several methodological caveats, functional imaging techniques could be preferentially sensitive to the earliest events of AD pathology prior to macroscopic grey matter loss and clinical manifestations of AD. We conclude that while these techniques have great potential to serve as biomarkers to identify at-risk individuals, more longitudinal studies with greater sample size and robust correction for multiple comparisons are still warranted to establish their utility.This study was supported by the National Institute for Health Research (NIHR, RG64473), Cambridge Biomedical Research Centre and Biomedical Research Unit in Dementia. Elijah Mak was in the receipt of the Gates Cambridge studentship
Low Energy Nuclear Reaction Aircraft- 2013 ARMD Seedling Fund Phase I Project
This report serves as the final written documentation for the Aeronautic Research Mission Directorate (ARMD) Seedling Fund's Low Energy Nuclear Reaction (LENR) Aircraft Phase I project. The findings presented include propulsion system concepts, synergistic missions, and aircraft concepts. LENR is a form of nuclear energy that potentially has over 4,000 times the energy density of chemical energy sources. It is not expected to have any harmful emissions or radiation which makes it extremely appealing. There is a lot of interest in LENR, but there are no proven theories. This report does not explore the feasibility of LENR. Instead, it assumes that a working system is available. A design space exploration shows that LENR can enable long range and high speed missions. Six propulsion concepts, six missions, and four aircraft concepts are presented. This report also includes discussion of several issues and concerns that were uncovered during the study and potential research areas to infuse LENR aircraft into NASA's aeronautics research
Developing the principles of chair based exercise for older people: a modified Delphi study
Background
Chair based exercise (CBE) is suggested to engage older people with compromised health and mobility in an accessible form of exercise. A systematic review looking at the benefits of CBE for older people identified a lack of clarity regarding a definition, delivery, purpose and benefits. This study aimed to utilise expert consensus to define CBE for older people and develop a core set of principles to guide practice and future research.
Methods
The framework for consensus was constructed through a team workshop identifying 42 statements within 7 domains. A four round electronic Delphi study with multi-disciplinary health care experts was undertaken. Statements were rated using a 5 point Likert scale of agreement and free text responses. A threshold of 70% agreement was used to determine consensus. Free text responses were analysed thematically. Between rounds a number of strategies (e.g., amended wording of statements, generation and removal of statements) were used to move towards consensus.
Results
16 experts agreed on 46 statements over four rounds of consultation (Round 1: 22 accepted, 3 removed, 5 new and 17 modified; Round 2: 16 accepted, 0 removed, 4 new and 6 modified; Round 3: 4 accepted, 2 removed, 0 new and 4 modified; Round 4: 4 accepted, 0 removed, 0 new, 0 modified).
Statements were accepted in all seven domains: the definition of CBE (5), intended users (3), potential benefits (8), structure (12), format (8), risk management (7) and evaluation (3).
The agreed definition of CBE had five components: 1. CBE is primarily a seated exercise programme; 2. The purpose of using a chair is to promote stability in both sitting and standing; 3. CBE should be considered as part of a continuum of exercise for frail older people where progression is encouraged; 4. CBE should be used flexibly to respond to the changing needs of frail older people; and 5. Where possible CBE should be used as a starting point to progress to standing programmes.
Conclusions
Consensus has been reached on a definition and a set of principles governing CBE for older people; this provides clarity for implementation and future research about CBE
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