The Chevron Bunionectomy for Moderate to Severe Deformity: Effects of Varying Procedural Factors in Hallux Valgus Correction

With growing popularity of minimally invasive surgery, the Chevron bunionectomy has been investigated for use in moderate to severe hallux valgus. This study investigates procedural components of lateral release, fixation, and 2nd digit procedures to evaluate effects on outcome. 109 out of 325 patients of a distal Chevron osteotomy with a minimum preoperative IMA of 15° completed the phone survey rating satisfaction and pain levels. Patients were contacted an average of 5.2 years postoperatively. 83% of patients reported being extremely to very satisfied with their outcome. Only 9 patients complained of current foot pain greater than or equal to 5 on a scale from 0 to 10 (with 0 being no pain). Intermetatarsal angle improved by an average of 7.2 degrees from 17.0 degrees preoperatively to 9.2 degrees postoperatively. Hallux valgus angle improved on average 20.5 degrees from 33.9 degrees preoperatively to 13.4 degrees postoperatively. Potential effects of risk factors on patient outcomes were also studied. No impacts of health history or 2nd digit procedures were found on patient satisfaction, pain levels, or radiographical improvement. However, surgeries including a lateral release were found to significantly improve IMA correction (p\u3c.01). No preference radiographically was discovered between open lateral release (OLR) and transarticular release (TAC). A higher rate of patients reported their satisfaction level of none to moderate for TAC (33%) than those without a release (17%) or OLR (12%). All measures comparing fixation methods proved unremarkable excluding a higher occurrence of K wire removal (40%) versus removal for bioabsorbable pins (10%). No cases of deep vein thrombosis or avascular necrosis were reported. Further studies investigating the differences between release types and frequency of implant removal are recommended

Effect of Cultural Strategies and Application Technologies on Weed Control in Flooded and Furrow-Irrigated Rice

Weed control is a major problem that rice (Oryza sativa L.) producers face in the Mid-south every growing season. Restricted use of some rice herbicides has also highlighted the need for more research to be conducted on cultural weed control strategies and application technologies in rice. The aim of these studies was to evaluate rice weed control using various rice row widths, bed widths (irrigation-furrow spacing), rice cultivar selection, and nozzle type selection. Three field experiments were conducted in 2021 and 2022 across four sites at Lonoke, AR, Pine Tree, AR, Rohwer, AR, and Stoneville, MS. In experiment one, as row width increased, barnyardgrass [Echinochloa crus-galli (L.) Beauv.] density increased. Barnyardgrass density increased by 120% in the 38-cm row width compared to the narrowest 13-cm row width at the preflood rice stage. Rice canopy coverage was reduced in the wider row widths early-season allowing increased barnyardgrass escapes. The hybrid cultivars resulted in a lower barnyardgrass density at the preharvest stage and higher grain yields than the inbred cultivars. Row width did not affect rice yield, indicating wider row widths could be feasible agronomically, but additional weed management efforts would be needed. The standard row width (19-cm) and hybrid cultivars would be recommended because growers would not need to purchase new equipment while maintaining weed management efforts and grain yields. In experiment two, similar results were observed that as rice row width increased, barnyardgrass density increased and rice canopy coverage decreased. The smallest droplet size-producing nozzle (XR) provided greater weed control throughout the study but is more prone to drift. Dual-fan nozzles (AITTJ60 and TTI60) had variable weed control impacts; however, they did have increased deposits on water-sensitive cards compared to single-fan counterparts (AIXR and TTI) indicating there may be potential for dual-fan nozzles to enhance weed control efforts. In conclusion, a narrower row width (e.g., 19-cm or less) and a smaller droplet size producing nozzle (XR), when drift is not a concern, are the most optimal for barnyardgrass control in a flooded rice system. In experiment three, any of the bed widths tested (76-, 97-, and 152-cm) could be used for maintaining effective weed control and yield in a furrow-irrigated rice system. The widest bed width of 152 cm had a slight increase in barnyardgrass density in the early rice life cycle but by harvest, panicle density did not differ from the narrower bed widths. Conversely, a decrease in barnyardgrass seed production was observed as the bed width increased. Similar rice canopy coverage and yields occurred between all three bed widths. The 13-cm row width had the lowest preflood barnyardgrass density, preharvest panicle count, and barnyardgrass seed production. No effect of row width was observed on rice canopy coverage; however, the 13-cm row width produced the greatest rice yield. The 13-cm row width may be the optimum row width option in furrow-irrigated rice paired with the 152-cm bed width to optimize weed management, particularly barnyardgrass seed production, while maintaining rice growth and yield

Effect of Cultural Strategies and Application Technologies on Weed Control in Flooded and Furrow-Irrigated Rice

Weed control is a major problem that rice (Oryza sativa L.) producers face in the Mid-south every growing season. Restricted use of some rice herbicides has also highlighted the need for more research to be conducted on cultural weed control strategies and application technologies in rice. The aim of these studies was to evaluate rice weed control using various rice row widths, bed widths (irrigation-furrow spacing), rice cultivar selection, and nozzle type selection. Three field experiments were conducted in 2021 and 2022 across four sites at Lonoke, AR, Pine Tree, AR, Rohwer, AR, and Stoneville, MS. In experiment one, as row width increased, barnyardgrass [Echinochloa crus-galli (L.) Beauv.] density increased. Barnyardgrass density increased by 120% in the 38-cm row width compared to the narrowest 13-cm row width at the preflood rice stage. Rice canopy coverage was reduced in the wider row widths early-season allowing increased barnyardgrass escapes. The hybrid cultivars resulted in a lower barnyardgrass density at the preharvest stage and higher grain yields than the inbred cultivars. Row width did not affect rice yield, indicating wider row widths could be feasible agronomically, but additional weed management efforts would be needed. The standard row width (19-cm) and hybrid cultivars would be recommended because growers would not need to purchase new equipment while maintaining weed management efforts and grain yields. In experiment two, similar results were observed that as rice row width increased, barnyardgrass density increased and rice canopy coverage decreased. The smallest droplet size-producing nozzle (XR) provided greater weed control throughout the study but is more prone to drift. Dual-fan nozzles (AITTJ60 and TTI60) had variable weed control impacts; however, they did have increased deposits on water-sensitive cards compared to single-fan counterparts (AIXR and TTI) indicating there may be potential for dual-fan nozzles to enhance weed control efforts. In conclusion, a narrower row width (e.g., 19-cm or less) and a smaller droplet size producing nozzle (XR), when drift is not a concern, are the most optimal for barnyardgrass control in a flooded rice system. In experiment three, any of the bed widths tested (76-, 97-, and 152-cm) could be used for maintaining effective weed control and yield in a furrow-irrigated rice system. The widest bed width of 152 cm had a slight increase in barnyardgrass density in the early rice life cycle but by harvest, panicle density did not differ from the narrower bed widths. Conversely, a decrease in barnyardgrass seed production was observed as the bed width increased. Similar rice canopy coverage and yields occurred between all three bed widths. The 13-cm row width had the lowest preflood barnyardgrass density, preharvest panicle count, and barnyardgrass seed production. No effect of row width was observed on rice canopy coverage; however, the 13-cm row width produced the greatest rice yield. The 13-cm row width may be the optimum row width option in furrow-irrigated rice paired with the 152-cm bed width to optimize weed management, particularly barnyardgrass seed production, while maintaining rice growth and yield

The Theory of Functional Connections: A Journey from Theory to Application

The Theory of Functional Connections (TFC) is a general methodology for functional interpolation that can embed a set of user-specified linear constraints. The functionals derived from this method, called "constrained expressions," analytically satisfy the imposed constraints and can be leveraged to transform constrained optimization problems to unconstrained ones. By simplifying the optimization problem, this technique has been shown to produce a numerical scheme that is faster, more accurate, and robust to poor initialization. The content of this dissertation details the complete development of the Theory of Functional Connections. First, the seminal paper on the Theory of Functional Connections is discussed and motivates the discovery of a more general formulation of the constrained expressions. Leveraging this formulation, a rigorous structure of the constrained expression is produced with associated mathematical definitions, claims, and proofs. Furthermore, the second part of this dissertation explains how this technique can be used to solve ordinary differential equations providing a wide variety of examples compared to the state-of-the-art. The final part of this work focuses on unitizing the techniques and algorithms produced in the prior sections to explore the feasibility of using the Theory of Functional Connections to solve real-time optimal control problems, namely optimal landing problems

Effects of Dietary Sodium Intake on Blood Flow Regulation During Exercise in Salt Resistant Individuals

PURPOSE: Dietary sodium intake guidelines is ≤2,300 mg/day, yet is exceeded by 90% of Americans. This study examined the impact of a high sodium diet on blood flow regulation during exercise. METHODS: Six males (25 ± 2 years) consumed dietary sodium intake guidelines for two weeks, with one week salt-capsule supplemented (HS: 6,900 mg/day of sodium) and the other week placebo-capsule supplemented (LS: 2,300 mg/day of sodium). At the end of each week, peripheral hemodynamic measurements [blood flow (BF), shear rate (SR), and flow mediated dilation (FMD)/SR)] of the brachial and superficial femoral artery were taken during handgrip (HG) and plantar flexion (PF) exercise, respectively. Each exercise workload was 3 minutes and progressed by 8 kilograms until exhaustion. RESULTS: There were no differences between LS and HS in blood pressure (82 ± 4 v 80 ± 5 mmHg; p = 0.3) or heart rate (56 ± 6 v 59 ± 10 bpm; p = 0.4). HG and PF exercise increased BF, SR, and FMD/SR across workload (p \u3c 0.03 for all), but no difference between diets (p \u3e 0.05 for all). CONCLUSION: Despite previous reports that HS impairs resting vascular function, this study revealed that peripheral vascular function and blood flow regulation during exercise is not impacted by a HS diet.https://scholarscompass.vcu.edu/gradposters/1082/thumbnail.jp

The Effects of a High Fat Meal on Blood Flow Regulation during Arm Exercise

A diet high in saturated fats results in endothelial dysfunction and can lead to atherosclerosis, a precursor to cardiovascular disease. Exercise training is a potent stimulus though to mitigate the negative effects of a high saturated fat diet; however, it is unclear how high-saturated fat meal (HSFM) consumption impacts blood flow regulation during a single exercise session. PURPOSE: This study sought to examine the impact of a single HSFM on peripheral vascular function during an acute upper limb exercise bout. METHODS: Ten young healthy individuals completed two sessions of progressive handgrip exercise. Subjects either consumed a HSFM (0.84 g of fat/kg of body weight) 4 hours prior or remained fasted before the exercise bout. Progressive rhythmic handgrip exercise (6kg, 12kg, 18kg) was performed for 3 minutes per stage at rate of 1 Hz. The brachial artery (BA) diameter and blood velocity was obtained using Doppler Ultrasound (GE Logiq e) and BA blood flow was calculated with these values. RESULTS: BA blood flow and flow mediated dilation (normalized for shear rate) during the handgrip exercise significant increased from baseline in all workloads, but no differences were revealed in response to the HSFM consumption. CONCLUSION: Progressive handgrip exercise augmented BA blood flow and flow mediated dilation in both testing days; however, there was no significant differences following the HSFM consumption. This suggests that upper limb blood flow regulation during exercise is unaltered by a high fat meal in young healthy individuals.https://scholarscompass.vcu.edu/gradposters/1060/thumbnail.jp

Deltas in arid environments

© The Author(s), 2021. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Day, J., Goodman, R., Chen, Z., Hunter, R., Giosan, L., & Wang, Y. Deltas in arid environments. Water, 13(12), (2021): 1677, https://doi.org/10.3390/w13121677.Due to increasing water use, diversion and salinization, along with subsidence and sea-level rise, deltas in arid regions are shrinking worldwide. Some of the most ecologically important arid deltas include the Colorado, Indus, Nile, and Tigris-Euphrates. The primary stressors vary globally, but these deltas are threatened by increased salinization, water storage and diversion, eutrophication, and wetland loss. In order to make these deltas sustainable over time, some water flow, including seasonal flooding, needs to be re-established. Positive impacts have been seen in the Colorado River delta after flows to the delta were increased. In addition to increasing freshwater flow, collaboration among stakeholders and active management are necessary. For the Nile River, cooperation among different nations in the Nile drainage basin is important. River flow into the Tigris-Euphrates River delta has been affected by politics and civil strife in the Middle East, but some flow has been re-allocated to the delta. Studies commissioned for the Indus River delta recommended re-establishment of some monthly water flow to maintain the river channel and to fight saltwater intrusion. However, accelerating climate impacts, socio-political conflicts, and growing populations suggest a dire future for arid deltas.This research received no external funding

Atmospheric parameters and rotational velocities for a sample of Galactic B-type supergiants

High resolution optical spectra of 57 Galactic B-type supergiant stars have been analyzed to determine their rotational and macroturbulent velocities. In addition, their atmospheric parameters (effective temperature, surface gravity and microturbulent velocity) and surface nitrogen abundances have been estimated using a non-LTE grid of model atmospheres. Comparisons of the projected rotational velocities have been made with the predictions of stellar evolutionary models and in general good agreement was found. However for a small number of targets, their observed rotational velocities were significantly larger than predicted, although their nitrogen abundances were consistent with the rest of the sample. We conclude that binarity may have played a role in generating their large rotational velocities. No correlation was found between nitrogen abundances and the current projected rotational velocities. However a correlation was found with the inferred projected rotational velocities of the main sequence precursors of our supergiant sample. This correlation is again in agreement with the predictions of single star evolutionary models that incorporate rotational mixing. The origin of the macroturbulent and microturbulent velocity fields is discussed and our results support previous theoretical studies that link the former to sub-photospheric convection and the latter to non-radial gravity mode oscillations. In addition, we have attempted to identify differential rotation in our most rapidly rotating targets.Comment: Submitted to MNRAS, 16 page