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To understand the historical context of and relationships between, the characteristics of shots at goal and match outcome in the Australian Football League. Observational. Descriptive statistics of shots at goal were calculated and compared across 20 seasons. The location, type, and outcome of all shots at goal (n = 43,254), by all teams (2017–19 & 21), were compared with match outcome. The total number of shots per match and the accuracy of shots haven't changed in two decades. Most teams win by having more shots at goal (Wilcoxon-r effect size 0.63) than their opponent (i.e. “majority strategy”) and of these, the number of open shots (0.48) is slightly more important than set shots (0.43), followed by shot accuracy (0.29). However, some teams (14 %) win by taking fewer shots at goal from field locations with a higher likelihood of scoring a goal (i.e. “minority strategy”). Arc angle and shot type can be used to predict the outcome of a shot at goal with 60.3 % classification accuracy. The novel shot-outcome prediction model reported here provides a better opportunity to evaluate goal kicking performance of teams and players, because it accounts for the type and difficulty of the shot. Teams can evaluate the shot accuracy of their players more fairly, by accounting for shot location using the method reported here. Coaches can compare the two shot strategies identified and implement the one that suits the skill profile of their players and increase their likelihood of winning.

Purpose Hip resurfacing arthroplasty (HRA) is recommended for younger patients seeking higher levels of activity. However, femoroacetabular cup impingement (FACI) between the femoral neck and acetabular prosthesis remains a concern. This study aimed to determine the incidence, risk factors, and prognostic consequences of FACI after HRA. Methods This study included 242 HRAs performed at a single institution. Three types of implants with different cup articular arc angle (CAAA) values were used. FACI was defined as indentation or spur formation at the femoral neck corresponding to the ridge of the acetabular cup. Multivariate regression analyses were conducted to identify risk factors for FACI. Clinical outcomes were compared between groups with and without impingement. The mean follow-up duration was 12 years (range, 2‒19). Results FACI was identified in 87 out of 242 HRAs (36%). Multivariate regression analysis showed that FACI was associated with the use of implants with a greater CAAA ( P  < 0.001). At the latest evaluation, the mean Harris Hip Score (94 vs. 93; P  = 0.405) and the incidence of groin pain (16.1% vs. 14.8%; P  = 0.795) were similar between the groups with and without FACI. Implant survivorship free of any revision was 94.5% in the FACI group and 89.8% in the non-FACI group at 12 years (log-rank, P  = 0.165). Conclusion This study identified that the incidence of FACI after HRA was 36%. Implants with greater CAAA were associated with a higher risk of impingement. However, radiographic FACI was not associated with adverse clinical outcomes of HRA after a mean follow-up of 12 years.

Savonius wind turbine is a common vertical axis wind turbine which simply comprises two or three arc-type blades and can generate power under poor wind conditions. With the aim of increasing the turbine’s power efficiency, the effect of the blade arc angle on the performance of a typical two-bladed Savonius wind turbine is investigated with a transient computational fluid dynamics method. Simulations were based on the Reynolds Averaged Navier–Stokes equations, and the renormalization group k − ε turbulent model was utilized. The numerical method was validated with existing experimental data. The results indicate that the turbine with a blade arc angle of 160 ∘ generates the maximum power coefficient, 0.2836, which is 8.37% higher than that from a conventional Savonius turbine.

Flat foot is a postural deformity in which the plantar part of the foot is either completely or partially contacted with the ground. In recent clinical practices, X-ray radiographs have been introduced to detect flat feet because they are more affordable to many clinics than using specialized devices. This research aims to develop an automated model that detects flat foot cases and their severity levels from lateral foot X-ray images by measuring three different foot angles: the Arch Angle, Meary’s Angle, and the Calcaneal Inclination Angle. Since these angles are formed by connecting a set of points on the image, Template Matching is used to allocate a set of potential points for each angle, and then a classifier is used to select the points with the highest predicted likelihood to be the correct point. Inspired by literature, this research constructed and compared two models: a Convolutional Neural Network-based model and a Random Forest-based model. These models were trained on 8000 images and tested on 240 unseen cases. As a result, the highest overall accuracy rate was 93.13% achieved by the Random Forest model, with mean values for all foot types (normal foot, mild flat foot, and moderate flat foot) being: 93.38 precision, 92.56 recall, 96.46 specificity, 95.42 accuracy, and 92.90 F-Score. The main conclusions that were deduced from this research are: (1) Using transfer learning (VGG-16) as a feature-extractor-only, in addition to image augmentation, has greatly increased the overall accuracy rate. (2) Relying on three different foot angles shows more accurate estimations than measuring a single foot angle.

For Geosynchronous Earth Orbit (GEO) objects, space-based optical surveillance has advantages over regional ground surveillance in terms of both the timeliness and space coverage. However, space-based optical surveillance may only collect sparse and short orbit arcs, and thus make the autonomous arc association and orbit determination a challenge for new GEO objects without a priori orbit information. In this paper, a three-step approach tackling these two critical problems is proposed. First, under the near-circular orbit assumption, a multi-point optimal initial orbit determination (IOD) method is developed to improve the IOD convergence rate and the accuracy of the IOD solution with angles-only observations over a short arc. Second, the Lambert equation is applied to associate two independent short arcs in an attempt to improve accuracy of the single-arc IOD semi-major axis (SMA) with the use of virtual ranges between the optical sensor and GEO object. The key idea in the second step is to generate accurate ranges at observation epochs, which, along with the real angle data, are then used to achieve much improved SMA accuracy. The third step is basically the repeated application of the second step to three or more arcs. The high success rate of arc associations and accurate orbit determination using the proposed approach are demonstrated with simulated space-based angle data over short arcs, each being only 3 min. The results show that the proposed approach is able to determine the orbit of a new GEO at a three-dimensional accuracy of about 15 km from about 10 arcs, each having a length of about 3 min, thus achieving reliable cataloguing of uncatalogued GEO objects. The IOD and two-arc association methods are also tested with the real ground-based observations for both GEO and LEO objects of near-circular orbits, further validating the effectiveness of the proposed methods.

A mechanism to reduce the porosity by changing the arc angle during aluminum alloy welding was studied. Industrial computed tomography was used to scan the welds with different arc angles, and the scanned model was processed by a specific software package to obtain the digital size and position of weld pores. The forces acting on the pores in the molten pool explained the test results that the number of pores decreases and the average size increases. As the inclination angle of the arc increased, the vertical component that prevented the bubble from rising decreased, and the horizontal component that pushed the molten metal flow and promoted the nucleation and growth of the bubbles increased. A horizontal movement during the droplet transition as the arc inclination was produced, which was conducive to the growth and overflow of bubbles. The theoretical analysis and temperature field measured by a far-infrared with different torch angle showed that when the arc was tilted from 0, the shape of the molten pool changed from the circle to the ellipse. The long axis of the ellipse increased as the bevel angle of the arc increased. This showed that the molten metal existed a longer time for the bubbles to escape from the molten pool when the angle of the arc increased. The paper provides fundamental insights into a mechanism for porosity reduction during the welding of Al alloys.

Occult obstetric anal sphincter injuries (OASI) are frequently underdiagnosed after vaginal delivery and may contribute to long-term pelvic floor dysfunction. Maternal pelvic anatomy has been suggested to influence the risk of sphincter injury; however, the role of the subpubic arch angle remains insufficiently explored. This prospective observational study included 300 primiparous women aged 18–40 years who underwent vaginal delivery with mediolateral episiotomy. The subpubic arch angle was measured antenatally using transperineal ultrasonography. All participants underwent ultrasound evaluation of the anal sphincter before delivery to exclude pre-existing injuries. External anal sphincter integrity was reassessed 24 h postpartum to identify occult injuries. Associations between the subpubic arch angle, maternal and neonatal characteristics, and the presence of occult anal sphincter injury were analyzed. Receiver operating characteristic (ROC) analysis was performed to explore an exploratory threshold of the subpubic arch angle for descriptive and comparative purposes. Occult external anal sphincter injury was identified in 96 women (32.0%). Women with sphincter injury had a significantly narrower mean subpubic arch angle compared with those without injury (109.24 ± 11.29° vs. 112.79 ± 11.39°, p  = 0.012). Maternal height was also significantly lower in women with sphincter injury ( p  < 0.05). No significant associations were observed between occult sphincter injury and fetal biometric parameters, labor induction, or the duration of the second stage of labor. ROC analysis demonstrated limited discriminative ability of the subpubic arch angle (AUC = 0.587; 95% CI 0.518–0.656). Using an exploratory threshold of 111.55°, occult sphincter injury was more frequent among women with narrower subpubic arch angles ( p  = 0.003). In this prospective cohort of primiparous women, occult obstetric anal sphincter injuries were more closely associated with maternal and pelvic anatomical factors than with fetal characteristics. A narrower subpubic arch angle was associated with an increased risk of occult sphincter injury, although its standalone discriminative performance was limited. The subpubic arch angle may provide adjunctive anatomical information within a multifactorial risk assessment framework, rather than serving as an independent screening or diagnostic parameter. Larger prospective and multicenter studies are warranted to further clarify its clinical relevance.

Questions/purposes The aim of this study was to identify prognostic factors associated with a poor quality of reduction and their relationships. Methods Data from medical charts for all patients admitted with acetabular fractures operated by open reduction and internal fixation (ORIF) from 2005 to 2014 were extracted. A total of 156 patients with a mean age of 40.3 years were included. All patients were reviewed at six months of follow-up. The prognostic factors analyzed were clinical and radiological factors. A new radiological parameter was also studied: the scanographic roof-arc angle. Specific statistical analysis was performed using a logistic regression model. Results Using a multivariate analysis logistic regression model: roof impaction ( p  = 0.001; OR = 6.59; CI 95% [2.01–20.97]), transverse + posterior wall ( p  = 0.03, OR = 2.52; CI 95% [1.46–13.65]) and surgeons in training ( p  = 0.02; OR = 1.24; CI 95% [1.07–3.32]) were three independent prognostic factors. Lower values of medial and posterior scanographic roof-arc angle were associated with unsatisfactory reduction. A significant association between unsatisfactory reduction and posterior roof arc angle < 61° was found. Conclusions Three independent prognostic factors associated with a risk of unsatisfactory reduction in ORIF for acetabular fractures were identified: roof impaction, transverse + posterior wall fracture and surgeons in training. Scanographic roof-arc angle seems to be a new prognostic factor. Level of Evidence Level 4 retrospective study

This study investigated position dependence in planning target volume (PTV)‐based and robust optimization plans using full‐arc and partial‐arc volumetric modulated arc therapy (VMAT). The gantry angles at the periphery, intermediate, and center CTV positions were 181°–180° (full‐arc VMAT) and 181°–360° (partial‐arc VMAT). A PTV‐based optimization plan was defined by 5 mm margin expansion of the CTV to a PTV volume, on which the dose constraints were applied. The robust optimization plan consisted of a directly optimized dose to the CTV under a maximum‐uncertainties setup of 5 mm. The prescription dose was normalized to the CTV D99% (the minimum relative dose that covers 99% of the volume of the CTV) as an original plan. The isocenter was rigidly shifted at 1 mm intervals in the anterior‐posterior (A‐P), superior‐inferior (S‐I), and right‐left (R‐L) directions from the original position to the maximum‐uncertainties setup of 5 mm in the original plan, yielding recalculated dose distributions. It was found that for the intermediate and center positions, the uncertainties in the D99% doses to the CTV for all directions did not significantly differ when comparing the PTV‐based and robust optimization plans (P > 0.05). For the periphery position, uncertainties in the D99% doses to the CTV in the R‐L direction for the robust optimization plan were found to be lower than those in the PTV‐based optimization plan (P < 0.05). Our study demonstrated that a robust optimization plan's efficacy using partial‐arc VMAT depends on the periphery CTV position.

The arc torch angle greatly affected the deposition characteristics in the wire arc additive manufacturing (WAAM) process, and the relation between the droplet transition behavior and macrostructure morphology was unclear. This work researched the effect of torch angle on the formation accuracy, droplet transition behavior and the mechanical properties in the WAAM process on a ZL205A aluminum alloy. The results suggested that at the obtuse torch angle, part of the energy input was used to heat the existing molten pool, which was optimized for the longer solidification period of the molten pool. Therefore, the greater layer penetration depth at 100° resulted in the improved layer-by-layer combination ability. The obtuse torch angle was associated with the better formation accuracy on the sidewall surface due to the smaller impact on the molten pool, which was influenced by both the arc pressure and droplet impact force. The eliminated pores were optimized for the mechanical properties of depositions at a torch angle of 100°; thus, the tensile strength and elongation attained maximum values of 258.6 MPa and 17.1%, respectively. These aspects made WAAM an attractive mode for manufacturing large structural components on ZL205A aluminum alloy.