1,041 research outputs found
The spatial and temporal characterisation of flooding within the floodplain wetland of the Nyl River, Limpopo Province, South Africa
The inundated area of a wetland is characterised by annual and interannual variability. This paper presents remotely-sensed imagery in order to better understand the spatial and temporal patterns of flooding within the floodplain wetland of the Nyl River, Limpopo Province. A detailed understanding of the hydrological characteristics of these flood events is essential in order to develop sustainable ecological and hydrological management plans for the area. From the results, flooding is shown to occur in 2 distinct phases. The initial phase is characterised by water ponding on the floodplain. The later phase is characterised by the input of water from tributaries to the north (e.g. Andriesspruit and Tobiasspriut) and southwest (e.g. Klein Nyl and Groot Nyl). This distinction may relate to the increasingly widespread practice of agricultural irrigation within adjacent tributary catchments. The methodology described in this study could yield valuable results when applied to other wetland systems in southern Africa.Keywords: Landsat, remote sensing, flood dynamics, floodplain wetlands, Nyl Rive
Physical activity and menopausal symptoms in women who have received menopause-inducing cancer treatments: results from the Women's Wellness After Cancer Program.
ObjectiveThis randomized controlled trial tested a digitally-delivered whole-of-lifestyle program for women previously treated for cancer. We investigated (1) associations between self-reported physical activity (PA) and menopausal symptoms and (2) if the intervention was associated with beneficial changes in PA and menopausal symptoms.MethodsWomen were randomized to intervention (nโ=โ142) or control (nโ=โ138). The intervention targeted lifestyle behavior including PA. Self-reported PA (International Physical Activity Questionnaire - Short Form) and menopausal symptom (Green Climacteric Scale, GCS) data were collected at baseline, with measures repeated at 12 weeks (end of intervention) and 24 weeks (to assess sustainability). Generalized estimating equation models explored associations between PA and GCS scores. Mixed-effects generalized equation models analyzed changes within and between groups in PA and GCS scores.ResultsTotal GCS scores were 1.83 (95% CI: 0.11-3.55) and 2.72 (95% CI: 1.12-4.33) points lower in women with medium and high levels of PA, respectively, than in women with low levels of PA. Total average GCS scores were 1.02 (0.21-2.26) and 1.61 (0.34-2.87) points lower in those undertaking moderate or vigorous intensity PA, respectively. Time spent walking, and performing moderate and vigorous PA were not different between intervention and control. The average GCS decrease of 0.66 points (95% CI: 0.03-1.29; p timeโ=โ0.03) over 24 weeks was not different between groups.ConclusionThis exploratory study established a stepwise association between moderate and vigorous PA and a lower total menopausal symptom score. The intervention did not appear to increase self-reported PA in women treated for early stage breast, reproductive, and blood cancers
Blocking of the B7-CD28 pathway increases the capacity of FasL<sup>+</sup> (CD95L<sup>+</sup>) dendritic cells to kill alloactivated T cells
Pressure dependent electronic properties of MgO polymorphs: A first-principles study of Compton profiles and autocorrelation functions
The first-principles periodic linear combination of atomic orbitals method
within the framework of density functional theory implemented in the CRYSTAL06
code has been applied to explore effect of pressure on the Compton profiles and
autocorrelation functions of MgO. Calculations are performed for the B1, B2,
B3, B4, B8_1 and h-MgO polymorphs of MgO to compute lattice constants and bulk
moduli. The isothermal enthalpy calculations predict that B4 to B8_1, h-MgO to
B8_1, B3 to B2, B4 to B2 and h-MgO to B2 transitions take place at 2, 9, 37, 42
and 64 GPa respectively. The high pressure transitions B8_1 to B2 and B1 to B2
are found to occur at 340 and 410 GPa respectively. The pressure dependent
changes are observed largely in the valence electrons Compton profiles whereas
core profiles are almost independent of the pressure in all MgO polymorphs.
Increase in pressure results in broadening of the valence Compton profiles. The
principal maxima in the second derivative of Compton profiles shifts towards
high momentum side in all structures. Reorganization of momentum density in the
B1 to B2 structural phase transition is seen in the first and second
derivatives before and after the transition pressure. Features of the
autocorrelation functions shift towards lower r side with increment in
pressure.Comment: 19 pages, 8 figures, accepted for publication in Journal of Materials
Scienc
Associations between cardiorespiratory fitness, physical activity and clustered cardiometabolic risk in children and adolescents: the HAPPY study
Clustering of cardiometabolic risk factors can occur during childhood and predisposes individuals to cardiometabolic disease. This study calculated clustered cardiometabolic risk in 100 children and adolescents aged 10-14ย years (59 girls) and explored differences according to cardiorespiratory fitness (CRF) levels and time spent at different physical activity (PA) intensities. CRF was determined using a maximal cycle ergometer test, and PA was assessed using accelerometry. A cardiometabolic risk score was computed as the sum of the standardised scores for waist circumference, blood pressure, total cholesterol/high-density lipoprotein ratio, triglycerides and glucose. Differences in clustered cardiometabolic risk between fit and unfit participants, according to previously proposed health-related threshold values, and between tertiles for PA subcomponents were assessed using ANCOVA. Clustered risk was significantly lower (pโ<โ0.001) in the fit group (mean 1.21โยฑโ3.42) compared to the unfit group (mean -0.74โยฑโ2.22), while no differences existed between tertiles for any subcomponent of PA. Conclusion These findings suggest that CRF may have an important cardioprotective role in children and adolescents and highlights the importance of promoting CRF in youth
Genetic Covariance Structure of Reading, Intelligence and Memory in Children
This study investigates the genetic relationship among reading performance, IQ, verbal and visuospatial working memory (WM) and short-term memory (STM) in a sample of 112, 9-year-old twin pairs and their older siblings. The relationship between reading performance and the other traits was explained by a common genetic factor for reading performance, IQ, WM and STM and a genetic factor that only influenced reading performance and verbal memory. Genetic variation explained 83% of the variation in reading performance; most of this genetic variance was explained by variation in IQ and memory performance. We hypothesize, based on these results, that children with reading problems possibly can be divided into three groups: (1) children low in IQ and with reading problems; (2) children with average IQ but a STM deficit and with reading problems; (3) children with low IQ and STM deficits; this group may experience more reading problems than the other two
Prostaglandin E2 Regulates AMPA Receptor Phosphorylation and Promotes Membrane Insertion in Preoptic Area Neurons and Glia during Sexual Differentiation
Sexual differentiation of the rodent brain is dependent upon the organizing actions of the steroid hormone, estradiol. In the preoptic area, a brain region critical for the expression of adult reproductive behavior, there are twice as many dendritic spine synapses per unit length on newborn male neurons compared to female neurons and this sex difference correlates with the expression of adult male copulatory behavior. The sex difference in the POA is achieved via estradiol's upregulation of the membrane-derived lipid signaling molecule prostaglandin E2 (PGE2); PGE2 is necessary and sufficient to masculinize both dendritic spine density and adult sexual behavior in rats. We have previously shown that PGE2 activates EP2 and EP4 receptors which increases protein kinase A (PKA) activity and that masculinized dendritic spine density and sex behavior are both dependent upon PKA as well as activation of AMPA type glutamate receptors. In the current experiments, we build upon this signaling cascade by determining that PGE2 induces phosphorylation of the AMPA receptor subunit, GluR1, which leads to increased AMPA receptor insertion at the membrane. Treating female pups on the day of birth with PGE2 induced the phosphorylation of GluR1 at the PKA-sensitive site within 2 hours of treatment, an effect that was blocked by co-administration of the PKA/AKAP inhibitor, HT31 with PGE2. Brief treatment of mixed neuronal/glial POA cultures with PGE2 or the cAMP/PKA stimulator, forskolin, increased membrane associated GluR1 in both neurons and glia. We speculate that PGE2 induced increases in AMPA receptor associated with the membrane underlies our previously observed increase in dendritic spine density and is a critical component in the masculinization of rodent sex behavior
The Frequency of Malaria Is Similar among Women Receiving either Lopinavir/Ritonavir or Nevirapine-based Antiretroviral Treatment
HIV protease inhibitors (PIs) show antimalarial activity in vitro and in animals. Whether this translates into a clinical benefit in HIV-infected patients residing in malaria-endemic regions is unknown. We studied the incidence of malaria, as defined by blood smear positivity or a positive Plasmodium falciparum histidine-rich protein 2 antigen test, among 444 HIV-infected women initiating antiretroviral treatment (ART) in the OCTANE trial (A5208; ClinicalTrials.gov: NCT00089505). Participants were randomized to treatment with PI-containing vs. PI-sparing ART, and were followed prospectively for โฅ48 weeks; 73% also received cotrimoxazole prophylaxis. PI-containing treatment was not associated with protection against malaria in this study population
Aging, working memory capacity and the proactive control of recollection:An event-related potential study
The present study investigated the role of working memory capacity (WMC) in the control of recollection in young and older adults. We used electroencephalographic event-related potentials (ERPs) to examine the effects of age and of individual differences in WMC on the ability to prioritize recollection according to current goals. Targets in a recognition exclusion task were words encoded using two alternative decisions. The left parietal ERP old/new effect was used as an electrophysiological index of recollection, and the selectivity of recollection measured in terms of the difference in its magnitude according to whether recognized items were targets or non-targets. Young adults with higher WMC showed greater recollection selectivity than those with lower WMC, while older adults showed nonselective recollection which did not vary with WMC. The data suggest that aging impairs the ability to engage cognitive control effectively to prioritize what will be recollected
Cisplatin-induced emesis: systematic review and meta-analysis of the ferret model and the effects of 5-HT3 receptor antagonists
PURPOSE: The ferret cisplatin emesis model has been used for ~30ย years and enabled identification of clinically used anti-emetics. We provide an objective assessment of this model including efficacy of 5-HT(3) receptor antagonists to assess its translational validity. METHODS: A systematic review identified available evidence and was used to perform meta-analyses. RESULTS: Of 182 potentially relevant publications, 115 reported cisplatin-induced emesis in ferrets and 68 were included in the analysis. The majority (nย =ย 53) used a 10ย mgย kg(โ1) dose to induce acute emesis, which peaked after 2ย h. More recent studies (nย =ย 11) also used 5ย mgย kg(โ1), which induced a biphasic response peaking at 12ย h and 48ย h. Overall, 5-HT(3) receptor antagonists reduced cisplatin (5ย mgย kg(โ1)) emesis by 68% (45โ91%) during the acute phase (day 1) and by 67% (48โ86%) and 53% (38โ68%, all Pย <ย 0.001), during the delayed phase (days 2, 3). In an analysis focused on the acute phase, the efficacy of ondansetron was dependent on the dosage and observation period but not on the dose of cisplatin. CONCLUSION: Our analysis enabled novel findings to be extracted from the literature including factors which may impact on the applicability of preclinical results to humans. It reveals that the efficacy of ondansetron is similar against low and high doses of cisplatin. Additionally, we showed that 5-HT(3) receptor antagonists have a similar efficacy during acute and delayed emesis, which provides a novel insight into the pharmacology of delayed emesis in the ferret
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