Explore the vast range of titles available.

Restoration programs require long-term monitoring and assessment of vegetation growth and productivity. Remote sensing technology is considered to be one of the most powerful technologies for assessing vegetation. However, several limitations have been observed with regard to the use of satellite imagery, especially in drylands, due to the special structure of desert plants. Therefore, this study was conducted in Kuwait’s Al Abdali protected area, which is dominated by a Rhanterium epapposum community. This work aimed to determine whether Unmanned Aerial Vehicle (UAV) multispectral imagery could eliminate the challenges associated with satellite imagery by examining the vegetation indices and classification methods for very high multispectral resolution imagery using UAVs. The results showed that the transformed difference vegetation index (TDVI) performed better with arid shrubs and grasses than did the normalized difference vegetation index (NDVI). It was found that the NDVI underestimated the vegetation coverage, especially in locations with high vegetation coverage. It was also found that Support Vector Machine (SVM) and Maximum Likelihood (ML) classifiers demonstrated a higher accuracy, with a significant overall accuracy of 93% and a kappa coefficient of 0.89. Therefore, we concluded that SVM and ML are the best classifiers for assessing desert vegetation and the use of UAVs with multispectral sensors can eliminate some of the major limitations associated with satellite imagery, particularly when dealing with tiny plants such as native desert vegetation. We also believe that these methods are suitable for the purpose of assessing vegetation coverage to support revegetation and restoration programs.

Exposure to acute bouts of whole body vibration (WBV), which can be employed as a novel form of exercise, has been reported to increase local skeletal muscle blood flow. However, the mechanism for this effect remains unclear. Therefore, this research aimed to explore the mechanism that would explain the effect of vibration on the peripheral cardiovascular function. Initially, the aim was to investigate the potential mechanism of the effect of WBV on the systemic blood flow, since there are currently no studies reporting any systemic effects of WBV on blood flow. The results did not demonstrate any systemic effects on blood flow (i.e. forearm blood flow) in response to acute unloaded and loaded squats with WBV. It was concluded that it was difficult to identify the effects of vibration on systemic cardiovascular function because, most likely due to the higher exercise intensity, skeletal muscle activation resulted in a decrement in blood flow from a distal site (i.e. forearm) to the main site (i.e. lower limb). Through the development of experimental methods involving applying vibration passively to the lower limbs, which avoids any influence of direct skeletal muscle activation and focuses solely on the mechanism inducing effects, it was demonstrated that ankle systolic blood pressure and ankle brachial pressure index substantially decreased in the post-vibration period. It was concluded that vibration has a direct effect on the peripheral cardiovascular function via increased vasodilatation; however, the mechanism underlying this effect remained unresolved. The effects of different durations of passive vibration on the peripheral circulation were also investigated and the results demonstrated that a longer duration of passive vibration (i.e. 8 minutes) resulted in a significantly higher lower leg blood flow during the recovery period than a shorter duration (i.e. 1, 2 and 4 minutes) of passive vibration. These data provide evidence for a greater effect of WBV occurring with a longer duration on the peripheral cardiovascular function, caused by the vasodilatation response throughout the recovery period. However, there might be a minimum effect of skeletal muscle activation occurring with a longer duration of passive vibration that leads to a direct response to localised heating. Furthermore, the thesis attempted to distinguish the effects of passive vibration on skeletal muscle activation from those on the peripheral vascular system. An experiment was designed in which passive vibration was applied with and without circulatory occlusion, to examine whether there was any underlying skeletal muscle activation. It was found that vibration with intact circulation produces more heat than the control, no vibration and occlusion, and occlusion plus vibration conditions. These effects were reflected by the higher skin temperature observed during exposure to vibration, and continuing into recovery. These data provide evidence that passive vibration does not appear to induce an increase in muscle activity. The data also suggest that the mechanism of the rise in skin temperature in response to passive vibration exposure is due to a vasodilatation that occurred in the lower limb via inducing an increase in shear stress at the blood vessels wall and led to an increase in circulating blood flow during exposure that continues into recovery. Overall, the results obtained demonstrate that vasodilatation occurs during and after vibration exposure and appears to be a process that is independent of skeletal muscle activation. It is postulated that the stimulus is a direct effect on the blood vessels via inducing an increase in shear stress that results in an increased vasodilatation, thereby increasing blood flow. Hence, these observations demonstrate that vibration stimulus has a direct effect on the muscle vascular bed as a primary effect and that there is no carry over effect into the systemic circulation. Thus, the results of this thesis indicate that vibration induced enhancement in the peripheral circulation could be using as a training stimulus and also could have a beneficial effect in assisting recovery routines from exertion.

Weight-management camp interventions for obese children are effective for short-term weight loss. However, there is little evidence indicating how gains made with such interventions can be maintained in the longer term. The present prospective cohort study investigated effectiveness of an intervention consisting of a weight-management camp followed by weekly lifestyle education sessions. Obese children from eight Qatari schools participated in the intervention from Jan 27 to May 20, 2015. It started with a 2 week weight-management camp involving physical and social activities, lifestyle learning, and dietary control. Participants then attended school as usual for 3 weeks. Ten, weekly after-school club sessions were then held, each lasting 2 h, involving further lifestyle education and engagement of participants’ parents, with the aim of encouraging consolidation of learning that had taken place at the camp, and continuation of healthy behaviours. A control group of obese children from the same Qatari schools received no intervention. The primary outcome variable was body-mass index SD scores (BMI SDS). Wilcoxon signed rank tests were used to assess changes in BMI SDS. Informed consent was obtained from participants and their parents. Ethics approval was granted by the Qatar University Institutional Review Board. 56 children (42 girls) aged 9–13 years (mean 10·9, SD 1·1) took part in the intervention. BMI SDS ranged from 1·17 to 4·00 (mean 2·51, SD 0·62). The control group consisted of 37 children (27 girls) aged 8–12 years (mean 10·3, SD 1·1) with BMI SDS 1·40–3·98 (2·78, 0·43). Between the start of camp and the end of the clubs, there was no significant change in control group BMI SDS (mean −0·004, SD 0·29; p=0·784), but significant reduction in the intervention group BMI SDS (−0·10, 0·20; p=0·0003). Significant BMI SDS reduction occurred for the intervention group during weight-management camp (−0·13, 0·12; p<0·0001) and after-school club (−0·12, 0·19; p<0·0001) stages; significant BMI SDS increase occurred between these stages (0·15, 0·16; p<0·0001). This small-sample study suggests that weekly lifestyle education sessions can be effective in helping to sustain weight-loss achievements from more intensive childhood obesity interventions. Half of the intervention group achieved an overall BMI SDS reduction of at least 0·10, which has been shown to be associated with important reductions in insulin and total cholesterol. This research was supported by the National Priorities Research Program Qatar Foundation (grant X-036-3–01).

The purpose of this study is to assess how subjective evaluation (heartburn, dysphagia, quality of life, and satisfaction) correlates with objective data after Heller myotomy and Dor fundoplication for achalasia. A total of 53 consecutive patients with achalasia undergoing laparoscopic Heller myotomy and Dor fundoplication were studied prospectively. Subjective evaluation was done preop and postop using the Gastroesophageal Reflux Disease Health-Related Quality of Life instrument (GERD-HRQL; 0 = best, 45 = worse), 4-point dysphagia and heartburn scales (0 = best, 3 = worst), patient satisfaction scale (0 = very satisfied, 5 = incapacitated), and the SF-12 general health-related quality-of-life score. At 3 months postop, patients were asked to undergo objective evaluation with 24-h pH testing, manometry, and endoscopy. Data are expressed as median (interquartile range) and analyzed by Wilcoxon signed rank test or Mann-Whitney U test. Forty-nine patients were more than 3 months postsurgery. Comparing preop to postop, improvements were found in dysphagia [3 (2-3) to 0 (0-1)], heartburn [1 (0-2) to 0 (0-1)], GERD-HRQL [13.5 (6.3-22.5) to 2 (0-5)], satisfaction [3 (3-4) to 1 (0-1)], and SF-12 mental component summary [46 (37-56) to 58 (50-59)] and physical component summary [46 (36-53) to 55 (48-56)] scores (p < 0.0001 for all). Thirty-eight patients (78%) agreed to undergo objective testing, and complete data were available for 32 (65%). Four of 32 patients (12.5%) had evidence of reflux based on 24-h pH testing. Of nine patients with GERD-HRQL >5, only two had positive pH test (22%). Of 23 patients with GERD-HRQL <5, two had positive pH test (7%). Of four tested patients with moderate to severe heartburn, two had an abnormal pH test. There was no significant relationship between GERD-HRQL score and pH test results. Lower esophageal sphincter pressure (LESP) decreased from 24 (16-35) to 13 mmHg (11-17) (p < 0.001). There was no relationship between dysphagia score and postop absolute LESP or a decrease in LESP after operation. Laparoscopic Heller myotomy and Dor fundoplication is an effective treatment for achalasia. Subjective evaluation can document patient satisfaction and health-related quality of life but does not accurately reflect postop reflux. Twenty-four-hour pH study is required to accurately assess reflux disease.

Although pneumoperitoneum (PP) decreases renal blood flow, it remains unclear whether this impacts renal function. Our aim was to characterize the effects of PP on renal perfusion and function using two fluid strategies for intravenous fluid administration. Twelve 30-kg pigs were randomized into two groups: maintenance (3 cc/kg/h of normal saline (NS)) and bolus (15 cc/kg/h + 20 cc/kg NaCl bolus prior to induction of PP). Pigs were studied in a blinded fashion for 30 min prior, 60 min during, and 30 min after release of 15 mmHg CO(2) PP. Cardiac output (CO) and stroke volume (SV) were measured using an esophageal Doppler probe, renal cortical perfusion (RCP) was measured with a laser Doppler probe on the right kidney, and renal function was measured using the fractional excretion of sodium (FeNa) and urine output. Statistical analysis was performed with area-under-the-curve (AUC) analysis and analysis of variance AUC analysis revealed moderate effect size for CO (0.416) and small effect size for SV (0.366) and RCP (0.363), with decreases seen in the control group but not the bolus group. During PP, urine output increased in the bolus group (p = 0.04) but not in the control group; there was no difference in FeNa in either group. Aggressive fluid hydration during CO(2) PP of 15 mmHg preserves CO, SV, and RCP while increasing urine output. No effect on renal function as measured by FeNa was observed in either group.