2,906 research outputs found
Sedimentation and Vegetation Colonization in Shah Tours Gully after Rehabilitation, Kilimanjaro, Tanzania
The Shah Tours gully, rehabilitated under the auspices of the project on Reducing Land Degradation in the Highlands of Kilimanjaro Region, is showing signs of recovery, only one year after rehabilitation. Check dams of stone and wire gabions, and sandbags, measuring 1.0 m high filled up with sediments at a rate of approximately 10.9 t ha-1 yr-1. Considering that the average depth of gully is 3.0 m, it is projected that it will take 2 more years for sediments to fill up the gully, if more layers of check dams are added to the existing ones. With respect to colonization by vegetation, there is 100% cover mainly by herbaceous layer (grasses and herbs), but also some shrubs and trees in the gully bed, which was rocky and devoid of plants before rehabilitation. These results will be crucial in planning for other gully-rehabilitation works in the Kilimanjaro region. Keywords Kilimanjaro ecosystem, land degradation, soil loss, rehabilitation, sediment deposition, vegetation colonizatio
Calibrated BOLD using direct measurement of changes in venous oxygenation
Calibration of the BOLD signal is potentially of great value in providing a closer measure of the underlying changes in brain function related to neuronal activity than the BOLD signal alone, but current approaches rely on an assumed relationship between cerebral blood volume (CBV) and cerebral blood flow (CBF). This is poorly characterised in humans and does not reflect the predominantly venous nature of BOLD contrast, whilst this relationship may vary across brain regions and depend on the structure of the local vascular bed. This work demonstrates a new approach to BOLD calibration which does not require an assumption about the relationship between cerebral blood volume and cerebral blood flow. This method involves repeating the same stimulus both at normoxia and hyperoxia, using hyperoxic BOLD contrast to estimate the relative changes in venous blood oxygenation and venous CBV. To do this the effect of hyperoxia on venous blood oxygenation has to be calculated, which requires an estimate of basal oxygen extraction fraction, and this can be estimated from the phase as an alternative to using a literature estimate. Additional measurement of the relative change in CBF, combined with the blood oxygenation change can be used to calculate the relative change in CMRO2 due to the stimulus. CMRO2 changes of 18 ± 8% in response to a motor task were measured without requiring the assumption of a CBV/CBF coupling relationship, and are in agreement with previous approaches
The psychological-type profile of clergywomen in ordained local ministry in the Church of England : pioneers or custodians?
This study employs psychological-type theory to compare the psychological profile of 144 clergywomen serving in ordained local ministry in the Church of England alongside the established profile of 237 professional mobile clergywomen serving in the Church of England published by Francis, Craig, Whinney, Tilley, and Slater. The data found no significant differences between these two groups of clergywomen in terms of orientations (introversion and extraversion) or in terms of the judging process (thinking and feeling). In terms of the perceiving process, there was a significantly higher proportion of sensing types among those serving in ordained local ministry (70% compared with 35%). In terms of the attitudes, there was a significantly higher proportion of judging types among those serving in ordained local ministry (83% compared with 65%). The combined sensing judging (SJ) temperament accounted for 65% of the clergywomen serving in ordained local ministry, compared with 29% of the clergywomen serving in professional mobile ministry in the earlier study. It is argued that the SJ temperament characterises a custodian style of ministry
Applying the behaviour change technique (BCT) taxonomy v1: a study of coder training.
Behaviour Change Technique Taxonomy v1 (BCTTv1) has been used to detect active ingredients of interventions. The purpose of this study was to evaluate effectiveness of user training in improving reliable, valid and confident application of BCTTv1 to code BCTs in intervention descriptions. One hundred sixty-one trainees (109 in workshops and 52 in group tutorials) were trained to code frequent BCTs. The following measures were taken before and after training: (i) inter-coder agreement, (ii) trainee agreement with expert consensus, (iii) confidence ratings and (iv) coding competence. Coding was assessed for 12 BCTs (workshops) and for 17 BCTs (tutorials). Trainees completed a course evaluation. Methods improved agreement with expert consensus (p < .05) but not inter-coder agreement (p = .08, p = .57, respectively) and increased confidence for BCTs assessed (both p < .05). Methods were as effective as one another at improving coding competence (p = .55). Training was evaluated positively. The training improved agreement with expert consensus, confidence for BCTs assessed, coding competence but not inter-coder agreement. This varied according to BCT.This work was carried out as part of the Behavior Change Technique Taxonomy project funded by the Medical Research Council via its Methodology panel [G0901474/1].This is the accepted manuscript version. The final publication is available from Springer at http://link.springer.com/article/10.1007%2Fs13142-014-0290-
Merleau-Ponty and neuroaesthetics: Two approaches to performance and technology
This is an Author's Accepted Manuscript of an article published in Digital Creativity, 23(3-4), 225 - 238, 2012. Copyright @ 2012 Taylor & Francis, available online at: http://www.tandfonline.com/10.1080/14626268.2012.709941.Assisted by the rapid growth of digital technology, which has enhanced its ambitions, performance is an increasingly popular area of artistic practice. This article seeks to contextualise this within two methodologically divergent yet complimentary intellectual tendencies. The first is the work of the philosopher Merleau-Ponty, who recognised that our experience of the world has an inescapably ‘embodied’ quality, not reducible to mental accounts, which can be vicariously extended through specific instrumentation. The second is the developing field of neuroaesthetics; that is, neurological research directed towards the analysis, in brain-functional terms, of our experiences of objects and events which are culturally deemed to be of artistic significance. I will argue that both these contexts offer promising approaches to interpreting developments in contemporary performance, which has achieved critical recognition without much antecedent theoretical support
7 tesla FMRI reveals systematic functional organization for binocular disparity in dorsal visual cortex.
The binocular disparity between the views of the world registered by the left and right eyes provides a powerful signal about the depth structure of the environment. Despite increasing knowledge of the cortical areas that process disparity from animal models, comparatively little is known about the local architecture of stereoscopic processing in the human brain. Here, we take advantage of the high spatial specificity and image contrast offered by 7 tesla fMRI to test for systematic organization of disparity representations in the human brain. Participants viewed random dot stereogram stimuli depicting different depth positions while we recorded fMRI responses from dorsomedial visual cortex. We repeated measurements across three separate imaging sessions. Using a series of computational modeling approaches, we report three main advances in understanding disparity organization in the human brain. First, we show that disparity preferences are clustered and that this organization persists across imaging sessions, particularly in area V3A. Second, we observe differences between the local distribution of voxel responses in early and dorsomedial visual areas, suggesting different cortical organization. Third, using modeling of voxel responses, we show that higher dorsal areas (V3A, V3B/KO) have properties that are characteristic of human depth judgments: a simple model that uses tuning parameters estimated from fMRI data captures known variations in human psychophysical performance. Together, these findings indicate that human dorsal visual cortex contains selective cortical structures for disparity that may support the neural computations that underlie depth perception.This work wassupported by the European Community’s Seventh Framework Programme FP7/2007-2013 (Grant
PITN-GA- 2011-290011), the Japan Society for the Promotion of Science (JSPS KAKENHI Grant 26870911), and the
Wellcome Trust (Grant 095183/Z/10/Z).This is the final version of the article. It was originally published in the Journal of Neuroscience, 18 February 2015, 35(7): 3056-3072; doi: 10.1523/JNEUROSCI.3047-14.2015
Diabetes in Old Male Offspring of Rat Dams Fed a Reduced Protein Diet
Restricted fetal growth is associated with increased
risk for the future development of Type 2 diabetes in
humans. The study aim was to assess the glucose tolerance
of old (seventeen months) male rats, which
were growth restricted in early life due to maternal
protein restriction during gestation and lactation. Rat
mothers were fed diets containing either 20% or 8%
protein and all offspring weaned onto a standard rat
diet. In old-age fasting plasma glucose concentrations
were significantly higher in the low protein offspring:
8.4 (1.3)mmol/l v. 5.3 (1.3)mmol/l (p = 0.005),
Areas under the curves were increased by 67% for
glucose (p = 0.01) and 81% for insulin (p = 0.01) in
these rats in intravenous glucose tolerance tests, suggesting
(a degree of) insulin resistance. These results
show that early growth retardation due to maternal
protein restriction leads to the development of diabetes
in old male rat offspring. The diabetes is predominantly
associated with insulin resistance
Evaluation of 2D Imaging Schemes for Pulsed Arterial Spin Labeling of the Human Kidney Cortex
Purpose A number of imaging readout schemes have been proposed for renal arterial spin labelling (ASL) to quantify kidney cortex perfusion, including gradient echo based methods of balanced fast field echo (bFFE) and gradient-echo echo-planar imaging (GE-EPI), or spin echo based schemes of spin-echo echo planar imaging (SE-EPI) and turbo spin-echo (TSE). Here, we compare these 2D imaging schemes to evaluate the optimal imaging scheme for pulsed ASL (PASL) assessment of human kidney cortex perfusion at 3 T.MethodsTen healthy volunteers with normal renal function were scanned using each 2D multislice imaging scheme, in combination with a respiratory triggered FAIR (flow-sensitive alternating inversion recovery) ASL scheme on a 3T Philips Achieva scanner. All volunteers returned for a second identical scan session within two weeks of the first scan session. Comparisons were made between the imaging schemes in terms of perfusion weighted image (PWI) signal-to-noise ratio (SNR) and perfusion quantification, temporal SNR (tSNR), spatial coverage, and repeatability.Results:For each imaging scheme, renal cortex perfusion was calculated (bFFE: 276 ± 29 ml/100g/min, GE-EPI: 222 ± 18 ml/100g/min, SE-EPI: 201 ± 36 ml/100g/min, TSE: 200 ± 20 ml/100g/min). Perfusion was found to be higher for GE based readouts compared to SE based readouts, with significantly higher measured perfusion for the bFFE readout compared to all other schemes (P < 0.05), attributed to the greater vascular signal present. Despite the PWI-SNR being significantly lower for SE-EPI compared to all other schemes (P < 0.05), the SE-EPI readout gave the highest tSNR and was found to be the most reproducible scheme for the assessment of kidney cortex, with a CoV of 17.2%, whilst minimizing variability of the perfusion weighted signal across slices for whole kidney perfusion assessment.ConclusionFor the assessment of kidney cortex perfusion using 2D readout schemes, SE-EPI provides optimal tSNR, minimal variability across slices and repeatable data acquired in a short scan time with low specific absorption rate
The impact of the resident duty hour regulations on surgical patients’ perceptions of care
Implementation of the 2003 Accreditation Council for Graduate Medical Education (ACGME) resident duty-hour regulations and access to publicly reported patient satisfaction measures have challenged administrators and clinicians to balance resident’s educational experience, patient care quality, and patients’ satisfaction and perceptions. A pre-post retrospective study design investigated association between implementation of ACGME regulations and patient satisfaction/perceptions using multinomial logistic regressions. The sample consisted of all surgical inpatients (July 2001 – June 2005), who responded to surveys at an academic medical center. Patients gave lower ratings for physician interactions (patient-physician interaction time, clinical updates, and courtesy) following the implementation of post-duty hour regulations. While the odds of patients rating “below good” post-implementation for physician survey questions (i.e., related to time spent, kept informed, and friendliness/ courtesy) were higher (i.e., 1.25 to 1.3) as compared to odds of rating “very good”, the overall rating of quality care improved post-implementation. This difference could be due to increased interaction of patients with other hospital personnel. To improve patient satisfactions and in turn their perceptions, initiatives such as workload balancing, hand-off protocols, patient communication, and interactive training for care providers are recommended. Finally, residency programs and institutions need to develop strategies for implementation of current and future ACGME duty hour regulations so as to balance patient safety, patient perceptions, and resident well-being
Quantitative assessment of renal structural and functional changes in chronic kidney disease using multi-parametric magnetic resonance imaging
BACKGROUND:Multi-parametric magnetic resonance imaging (MRI) provides the potential for a more comprehensive non-invasive assessment of organ structure and function than individual MRI measures, but has not previously been comprehensively evaluated in chronic kidney disease (CKD).METHODS:We performed multi-parametric renal MRI in persons with CKD (n = 22, 61 ± 24 years) who had a renal biopsy and measured glomerular filtration rate (mGFR), and matched healthy volunteers (HV) (n = 22, 61 ± 25 years). Longitudinal relaxation time (T1), diffusion-weighted imaging, renal blood flow (phase contrast MRI), cortical perfusion (arterial spin labelling) and blood-oxygen-level-dependent relaxation rate (R2*) were evaluated.RESULTS:MRI evidenced excellent reproducibility in CKD (coefficient of variation
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