Descent Angle Research Articles

Predicting Vaginal Delivery Success: Role of Intrapartum Transperineal Ultrasound Angle of Descent at a Single Center.

BACKGROUND Assessment of labor progress via digital vaginal examination is subjective, while intrapartum transperineal ultrasonography is deemed more objective and effective. The angle of descent (AoD) is a reliable intrapartum transperineal ultrasound parameter with minimal inter-observer and intra-observer errors. This study compared intrapartum transperineal ultrasonography with digital vaginal examination in evaluating the angle of descent for vaginal delivery selection in 70 women. MATERIAL AND METHODS This cross-sectional study was conducted at Dr. Mohammad Hoesin Hospital Palembang in Indonesia, using a consecutive sampling method to measure AoD of 70 patients at admission and every 2 h during labor progression. Patients were monitored until childbirth, and outcomes of successful vaginal or cesarean delivery were reported. A diagnostic test determined the optimal AoD for predicting successful vaginal delivery and its predictive value. RESULTS The study included 70 patients with a mean age of 28.29±6.09 years and a body mass index of 30.59±3.49 kg/m². Among them, 29 (41%) had successful vaginal deliveries. Adequate contraction frequency at admission was strongly associated with successful vaginal delivery (P<0.001). The optimal AoD for predicting successful vaginal delivery was 94.5°, with an area under the curve of 0.567 (95% CI 0.425-0.710), sensitivity of 84.2%, specificity of 45.7%, and accuracy of 54.3%. CONCLUSIONS Intrapartum transperineal ultrasonography for measuring AoD can be a valuable adjunct in labor management. Further investigations are needed to validate the optimal AoD in Indonesian pregnant women.

Global prediction and analysis for helicopter noise footprint based on acoustic modes.

Aiming to address the significant external noise produced by helicopter rotors, an integrated process based on acoustic modes has been developed for predicting the global noise footprint. The proposed method has the advantages of global prediction, analysis, and low computational costs. The key steps involve constructing an acoustic modal database and efficient prediction of noise footprint. First, the global noise model is utilized to map the time-domain sound pressure to amplitudes and coefficients in the acoustic modal domain. Acoustic mode coefficients representing various flight states are systematically cataloged in the database. Subsequently, the coefficients are extracted based on the characteristic parameters of trajectory elements, allowing for the evaluation of noise radiation in the acoustic modal domain. To investigate the impact of descent angle and advance ratio on the noise footprint, a simulation study is conducted in the forward and approach flight with an AS350 helicopter. Results indicated that, for a region with 1800 observers, the computational time of the developed approach requires only one-fifth of the time compared to the traditional Rotorcraft Noise Model method. This remarkable reduction in computation time, along with the global predictive capability, supports the practicality of efficient noise footprint assessment in both military and civilian contexts.

Case study based on ball trajectory and motion analysis of international long-drive distance golf player

This study aimed to measure the ball trajectory, club face control, and body movements of a long-drive distance golf player (LDP) who excels in international competitions. The participant randomly executed 10 shots of three trajectory types—straight, draw, and fade—using a driver in an indoor facility. The results indicated that the fade shot exhibited a significantly longer ball carry distance (S: 329.7 ± 31.7, D: 301.8 ± 30.6, F: 345.7 ± 18.4 yards). The offline distance also showed a significant increase (S: 3.6 ± 37.3, D: −12.0 ± 26.4, F: 30.8 ± 42.2 yards) for the fade shot. If shots exceeding the 60-yard width of the offline distance resulting in invalid attempts were counted, there were 2 of 10 attempts for straight, 0 of 10 attempts for draw, and 4 of 10 attempts for fade. Analysis of the ball trajectory of draw shots revealed a statistically significant trend towards lower peak height and descent angle. In all three trajectories, there were no significant differences observed in ball speed (S: 189.3±6.3, D: 192.1±5.0, F: 193.3±4.1 mph) and club head speed (S: 137.2 ± 1.6, D: 137.0 ± 1.2, F: 137.7 ± 2.2 mph). For the draw shots, the club path exhibited in-to-out trajectory, moving the club face, and the face angle was open during the ball impact. It is evident that even in golf players aiming for the maximum distance in a single shot, club head speed and grip speed tend to remain relatively constant. The findings indicate that the LDP executes precise movement and face control tailored to the three ball trajectories, demonstrating sophisticated motor control.

Prediction of Failure to Progress after Labor Induction: A Multivariable Model Using Pelvic Ultrasound and Clinical Data.

Objective: Labor induction is one of the leading causes of obstetric admission. This study aimed to create a simple model for predicting failure to progress after labor induction using pelvic ultrasound and clinical data. Material and Methods: A group of 387 singleton pregnant women at term with unruptured amniotic membranes admitted for labor induction were included in an observational prospective study. Clinical and ultrasonographic variables were collected at admission prior to the onset of contractions, and labor data were collected after delivery. Multivariable logistic regression analysis was applied to create several models to predict cesarean section due to failure to progress. Afterward, the most accurate and reproducible model was selected according to the lowest Akaike Information Criteria (AIC) with a high area under the curve (AUC). Results: Plausible parameters for explaining failure to progress were initially obtained from univariable analysis. With them, several multivariable analyses were evaluated. Those parameters with the highest reproducibility included maternal age (p < 0.05), parity (p < 0.0001), fetal gender (p < 0.05), EFW centile (p < 0.01), cervical length (p < 0.01), and posterior occiput position (p < 0.001), but the angle of descent was disregarded. This model obtained an AIC of 318.3 and an AUC of 0.81 (95% CI 0.76-0.86, p < 0.0001) with detection rates of 24% and 37% for FPRs of 5% and 10%. Conclusions: A simplified clinical and sonographic model may guide the management of pregnancies undergoing labor induction, favoring individualized patient management.

Research on the Aerodynamic Characteristics of the Relationship between Lift-to-drag Ratio and Wing Shape of Gliders

A glider is a special type of aircraft without a power unit, which relies on the lift of airflow to resist weight. The characteristics of a glider are essential to its flight performance, which includes aspect ratio, sweepback, and taper ratio. Proper design of the wing shape can help achieve good performance, so research on these elements can be helpful. This paper aims to calculate the relationship between the aspect ratio and lift-drag coefficient which affects the performance of gliders. By calculation, this paper found out that high aspect ratio aircraft could generate more lift force and was optimum in designing gliders. Then an experiment with a paper plane was designed to show the impact of aspect ratio on glider performance. Then a paper airplane experiment was designed, and the changes in different aspect ratios were achieved by reshaping the wings of the paper airplane, while flight performance was estimated by the lift drag coefficient and descent angle of the glider. After data collection, calculation and analysis, different flight routes were recorded, and based on this, the lift drag coefficient and descent angle were calculated. The experimental results indicate that aspect ratio is one but not the only factor affecting the flight performance of gliders. Through theoretical analysis and experiments, this study verifies the basic mechanism of the influence of wing shape, especially aspect ratio, on glider flight, providing new ideas for improving glider performance.

A Fuzzy-Based System for Autonomous Unmanned Aerial Vehicle Ship Deck Landing.

This paper introduces a fuzzy logic-based autonomous ship deck landing system for fixed-wing unmanned aerial vehicles (UAVs). The ship is assumed to maintain a constant course and speed. The aim of this fuzzy logic landing model is to simplify the task of landing UAVs on moving ships in challenging maritime conditions, relieving operators from this demanding task. The designed UAV ship deck landing model is based on a fuzzy logic system (FLS), which comprises three interconnected subsystems (speed, lateral motion, and altitude components). Each subsystem consists of three inputs and one output incorporating various fuzzy rules to account for external factors during ship deck landings. Specifically, the FLS receives five inputs: the range from the deck, the relative wind direction and speed, the airspeed, and the UAV's flight altitude. The FLS outputs provide data on the speed of the UAV relative to the ship's velocity, the bank angle (BA), and the angle of descent (AOD) of the UAV. The performance of the designed intelligent ship deck landing system was evaluated using the standard configuration of MATLAB Fuzzy Toolbox.

Time- and Energy-Saving Potentials of Efficient Urban Air Mobility Airspace Structures

Novel electric propulsion technology has given rise to thinking about urban air mobility in a new way with its expected high degree of operational flexibility. The designs of electric vertical takeoff and landing configurations are determined by their mission profile, which we found to be oversimplified at many points in the current scientific literature. There is a gap of understanding in how mission profiles impact travel time and energy demand. In this paper, we review various mission designs, formulate a five-segment flight profile (including vertical ascent, climb, cruise, descent, and vertical approach), and apply it on a fleet level of up to 200,000 urban air mobility trips. The demand data originate from the Upper Bavaria region study, OBUAM. In a sensitivity study, we vary the cruise altitude, the height of the vertical flight segments, and the climb and descent angles for two vehicle configurations: a fixed-wing tilt-rotor concept, and a multicopter concept. The main findings for the fixed-wing concept are that the height of the vertical flight segments and the cruise altitude should be as low as possible, and small climb angles (below 7 deg) should be avoided. The multicopter concept, however, is penalized by fast forward flight while being comparatively insensitive to both the cruise altitude and height of the vertical flight segments. Furthermore, we found a tradeoff between time- and energy-optimal flights with the a energy-optimized climb/descent angle at around 10 deg.

강하각 유지를 위한 강하율 산정 연구

강하각 유지를 위한 강하율 산정 연구

Theoretical aspects of the increase in the efficiency of sowing grain crops in resource-saving technologies

The paper presents theoretical studies of the aspects of increasing efficiency of sowing during the implementation of resource-saving technologies, which allow determining the speed of the seed at any time of its movement along the curvilinear section of the distributor and at the moment it leaves the surface of the distributor. The main factors influencing the distance and trajectory of the flight of seeds, taking into account the arch of the under-shoulder space, were identified. Graphical dependences of the flight distance of the seed on its speed when leaving the distributor surface, on the angle of the seed descent from the distributor and on the installation height of the seed distributor above the soil surface were plotted. The analysis of dependences allowed concluding that in order to obtain the greatest flight distance of seeds in the under-shoulder space, it is necessary to have the maximum installation height of the seed distributor and the speed of the seeds when leaving its surface. The angle of descent of seeds from the curved part of the distributor should tend to zero with the horizontal axis, subject to the condition of the absence of their impacts on the internal elements of a coulter. These graphic dependencies allow determining the numerical values of the specified parameters for blade coulters with different design characteristics.

Justification choice parameters material input receiving and distributing device in the horizontal type air grain cleaning machine

The paper presents studies to determine the angle of inclination of the surface from the coefficient of friction for organic glass in an air grain cleaning machine. Earlier studies of the physico-mechanical properties of grain seeds have shown that for steel, the angle of descent of wheat is 36.2 – 37 degrees at a humidity of 15%-16%.

Optimization Efficiency of the Aircraft Wing of Cessna 172 Skyhawk by Absorbent Adverse Pressure Using Tangential Suction Slot Without Vacuum Device

Efficiency of a wing is sufficient at stall angle of attack and breakdown by effecting turbulent flow intensity on upper wing surface which is destroyed the airflow pattern and generated adverse pressure, backflow airstream and forward transition separation point movement closely to the leading edge of the wing. To enhancement a wing efficiency factor at high angle of attacks in this research is using partially sucking adverse pressure to delay the separation point to control the backflow rate and expelling it through the wing tips ends using tangential suction slot channel without using any mechanical means depending on differential static pressure between adverse pressure and the static pressure generated on both win tips ends. Numerical CFD analysis has been managed the case study of the effect suction slot channel located on the upper wing surface at (70%) of the wing chord from the leading edge as a proposed modified wing model of the Cessna 172 Skyhawk half wing at angle of attacks (10°, 12°, 14°, 16°, 18°, 20°, 22°, 24°). The analysis study was conducted at stall speed (90 km/hr.) without flaps where it is equal (25 m/sec). The results of the analytical shows at the range of angle of attacks were chosen between (10° to 24°), lift coefficient CL increased (3.757%), drag coefficient CD is decreased (0.530%) and the wing efficiency lift to drag ratio Δ(CL/CD) is increased to (5.712%) while Δ(CD/CL) is decreased to (5.231%) which these parameters reflected to enhancement the wing to reduce required power at the minimum speed, increase angle of climb and decrease angle of descent reduce landing distance with high angle of attacks.

Investigating a Computational Explanation of the Black Hole Illusion

ABSTRACT Objective We investigated the role of Perrone’s algorithm in the Black Hole Illusion (BHI). After analyzing the algorithm and identifying two of its predictions, we empirically tested them with two on-line experiments. Background In 1983, Perrone proved that in daylight conditions it is possible to compute the descent angle using a ratio of retinal distances corresponding to the runway and surrounding context. Using the algorithm in nighttime conditions, with just the visible runway, pilots would overestimate the descent angle, leading to the BHI. Method Mathematical analysis indicates the algorithm predicts a large BHI; perhaps too large if there are no mitigating factors. As Perrone noted, the BHI illusion magnitude should be affected by runway width; we also found that some conditions predict a reverse BHI (pilots should underestimate their descent angle). In our experiments, participants observed a cockpit view of a runway during five seconds of steady approach. In a subsequent still image, participants indicated where they believed the plane would land if it continued its flight path. We measured the accuracy of the landing positions for various runway widths and various background contexts. Results The experiments did not show a BHI for any conditions; so the experiments do not validate the model predictions. Conclusion Based on our analyses, Perrone’s algorithm does not provide an adequate explanation of the Black Hole Illusion.

The Black Hole Illusion: Theory and Tests

The Black Hole Illusion (BHI) is a nighttime aviation landing illusion that occurs when only the runway is visible to pilots. With this illusion, pilots overestimate their descent angle, which causes them to overestimate their height, compensate by flying lower, and crash into the ground. Perrone (1983) proved that, in daylight conditions, it is possible to compute the descent angle using a ratio of retinal distances of the runway. He also showed that using a modified algorithm, which applies in nighttime conditions with just the visible runway, pilots would overestimate the descent angle, ultimately leading to the BHI. We quantitatively analyzed Perrone’s algorithm to determine whether it is a viable explanation for the BHI. Our analysis finds that, if Perrone’s algorithm was a complete explanation of the BHI, pilots would sometimes crash planes nearly half a kilometer before the start of the runway, which is much larger than what has been observed. To further investigate the role of Perrone’s algorithm, we derived and tested two additional predictions. First, we quantified an observation made by Perrone that the BHI illusion magnitude should be affected by the runway width. Second, we discovered that some conditions of runway width and length predict a reverse BHI such that pilots should underestimate their angle of descent and compensate by flying higher (and landing later) than is necessary. We are empirically testing our predictions with an on-line experiment using simulated landing flight paths. Participants observe a cockpit view of a runway during five seconds of approach. In a subsequent still image, the participant indicates where they believe the plane will land if it continues on its flight path. We measure the accuracy of landing positions for various runway widths/lengths and for various background contexts: Black, green, and textured grass.

Fetal head descent assessed by transabdominal ultrasound: a prospective observational study

Determining fetal head descent, expressed as fetal head station and engagement is an essential part of monitoring progression in labor. Assessing fetal head station is based on the distal part of the fetal skull, whereas assessing engagement is based on the proximal part. Prerequisites for assisted vaginal birth are that the fetal head should be engaged and its lowermost part at or below the level of the ischial spines. The part of the fetal head above the pelvic inlet reflects the true descent of the largest diameter of the skull. In molded (reshaped) fetal heads, the leading bony part of the skull may be below the ischial spines while the largest diameter of the fetal skull still remains above the pelvic inlet. An attempt at assisted vaginal birth in such a situation would be associated with risks. Therefore, the vaginal or transperineal assessments of station should be supplemented with a transabdominal examination. We suggest a method for the assessment of fetal head descent with transabdominal ultrasound. To investigate the correlation between transabdominal and transperineal assessment of fetal head descent, and to study fetal head shape at different labor stages and head positions. Women with term singleton cephalic pregnancies admitted to the labor ward for induction of labor or in spontaneous labor, at the Cairo University Hospital and Oslo University Hospital from December 2019 to December 2020 were included. Fetal head descent was assessed with transabdominal ultrasound as the suprapubic descent angle between a longitudinal line through the symphysis pubis and a line from the upper part of the symphysis pubis extending tangentially to the fetal skull. We compared measurements with transperineally assessed angle of progression and investigated interobserver agreement. We also measured the part of fetal head above and below the symphysis pubis at different labor stages. The study population comprised 123 women, of whom 19 (15%) were examined before induction of labor, 8 (7%) in the latent phase, 52 (42%) in the active first stage and 44 (36%) in the second stage. The suprapubic descent angle and the angle of progression could be measured in all cases. The correlation between the transabdominal and transperineal measurements was-0.90 (95% confidence interval,-0.86 to-0.93). Interobserver agreement was examined in 30 women and the intraclass correlation coefficient was 0.98 (95% confidence interval, 0.95-0.99). The limits of agreement were from-9.5 to 7.8 degrees. The fetal head was more elongated in occiput posterior position than in non-occiput posterior positions in the second stage of labor. We present a novel method of examining fetal head descent by assessing the proximal part of the fetal skull with transabdominal ultrasound. The correlation with transperineal ultrasound measurements was strong, especially early in labor. The fetal head was elongated in the occiput posterior position during the second stage of labor.

Leg rings impact the diving performance of a foot‐propelled diver

Leg rings are frequently used to mark aquatic birds in order to identify individuals, and study population dynamics and migration patterns, with the proviso being that the rings should not affect the birds. The effects of tags and rings are of particular interest in diving birds because any change in body shape could impact swimming efficiency and costs, as water is almost a thousand times denser than air. We attached tri‐axial accelerometers to both ringed and unringed breeding Imperial Shags Leucocarbo atriceps to assess dive performance based on descent angle, descent rate, power stroke rate, power stroke peak acceleration amplitude and Vectorial Dynamic Body Acceleration (VeDBA) as a proxy for energy expenditure. Ringed birds, especially females, had a higher foot‐stroke amplitude than unringed animals. In addition, the overall efficiency of the ringed individuals, as expressed by the descent rate per unit VeDBA, was compromised (by 3.5% in females and 4.3% in males) compared with unringed birds. We conclude that leg rings change the diving performance of Imperial Shags, although the effect is small and may not affect reproductive success. However, given that birds are typically ringed for life, we urge researchers to be particularly careful about the potential cumulative effect of attaching leg rings to foot‐propelled diving species.

Levator plate descent angle in pelvic floor disorders.

The levator plate descent angle (LPDA) quantifies the levator plate position with reference to the pubic bone and perineal body at rest. Unfortunately, research on this notable new parameter is lacking, but it is clear that levator ani deficiency (LAD) will undermine the fundamental role of the levator ani muscle (LAM) in organ support. The aim of this study was to establish the relationship between the LPDA and LAD in patients with pelvic floor disorders. This retrospective study was conducted at Seoul Songdo Hospital, Korea between August 2019 and August 2020 on women with symptoms of pelvic floor disorder such as urinary incontinence, constipation, and fecal incontinence. In all cases, three-dimensional pelvic floor ultrasound was performed for LAD scoring, minimal levator hiatus, and LPDA evaluation. We evaluated LAD using a scoring system that graded levator injury according to the insertion point of each subdivision scored unilaterally. For the entire LAM group, a cumulative LAD score that ranged between 0 and 18 was possible. Scores were categorized as mild (0-6 points), moderate (7-12 points), and severe (13-18 points) deficiency RESULTS: A total of 93 patients were included in the study (mean age 65.89 ± 11.12 [range, 34-86] years). Thirteen participants had mild LAD scores (14.0%), 42 had moderate LAD scores (45.2%), and 38 had severe LAD scores (40.9%). There was a significant difference in mean age (59.23 ± 12.55years vs. 64.43 ± 10.03 vs. 69.79 ± 10.55years, p = 0.005) and mean parity (1.85 ± 0.90 vs 2.48 ± 1.15 vs 2.76 ± 1.10, p = 0.038) of patients between groups. There was also a significant difference in the mean Wexner incontinence score (7.14 ± 3.63 vs 7.24 ± 5.76 vs 11.41 ± 5.54, p = 0.028) and in the mean fecal incontinence quality of life (FIQOL) score (12.91 ± 3.11 vs 14.10 ± 3.87 vs 10.41 ± 3.65, p = 0.014). The mean value of the LPDA in the group with mild LAD scores was 14.65° (SD ± 3.54) and in the group with moderate LAD scores was 9.66° (SD ± 3.36). In the group with severe LAD scores, the mean LPDA was 1.83° (SD ± 4.71). The mean value for minimal levator hiatus (MLH) area in the mild LAD score group was 14.16cm2 (SD ± 2.72), that in the moderate LAD score group was 15.82cm2 (SD ± 2.30), and that in the severe LAD score group was 17.99cm2 (SD ± 2.81). There were significant differences between the three groups both in decreasing LPDA (p < 0.001) and increasing MLH (p < 0.001). There was a negative correlation between the LAD score and LPDA and the Pearson correlation coefficient was -0.528 (moderate correlation). There was a positive correlation between the LAD score and MLH, and the Pearson correlation coefficient was 0.303 (weak correlation). The LAD score and LPDA have a moderate negative correlation. In patients with severe pelvic floor symptoms and extensive LAM injury, high LAD scores and low LPDA results were confirmed. In the treatment of patients with pelvic floor disorders, the LPDA seems to be a very useful parameter in determining the severity of structural defects.

Domestic egg-laying hens, Gallus gallus domesticus, do not modulate flapping flight performance in response to wing condition.

Wild birds modulate wing and whole-body kinematics to adjust their flight patterns and trajectories when wing loading increases flight power requirements. Domestic chickens (Gallus gallus domesticus) in backyards and farms exhibit feather loss, naturally high wing loading, and limited flight capabilities. Yet, housing chickens in aviaries requires birds to navigate three-dimensional spaces to access resources. To understand the impact of feather loss on laying hens' flight capabilities, we symmetrically clipped the primary and secondary feathers before measuring wing and whole-body kinematics during descent from a 1.5 m platform. We expected birds to compensate for increased wing loading by increasing wingbeat frequency, amplitude and angular velocity. Otherwise, we expected to observe an increase in descent velocity and angle and an increase in vertical acceleration. Feather clipping had a significant effect on descent velocity, descent angle and horizontal acceleration. Half-clipped hens had lower descent velocity and angle than full-clipped hens, and unclipped hens had the highest horizontal acceleration. All hens landed with a velocity two to three times greater than in bird species that are adept fliers. Our results suggest that intact laying hens operate at the maximal power output supported by their anatomy and are at the limit of their ability to control flight trajectory.

Obstructed Defecation Symptom Severity and Degree of Rectal Hypermobility and Folding Detected by Dynamic Ultrasound.

We used dynamic pelvic floor ultrasound to investigate the relationship between obstructed defecation symptom (ODS) severity and the degree of rectal hypermobility/folding. In this retrospective study, women who presented with ODS from October 2017 to January 2019 and underwent an interview, pelvic examination, and pelvic floor ultrasound were recruited. Patients were diagnosed with abdominal constipation, dyssynergia, or pelvic constipation. Pelvic constipation patients were categorized based on their reported frequency of incomplete emptying of stool (<50% or ≥50% of bowel movements) representing mild and severe ODS, respectively. Using dynamic ultrasound, rectal hypermobility was quantified via rectovaginal septum length at rest and Valsalva and its compression ratio, where shorter lengths and larger compression ratios are indicative of increased rectal hypermobility. One hundred twenty-one patients (41 with abdominal constipation, 7 with dyssynergia, and 73 with pelvic constipation) were included. Compression ratios were higher in women with severe versus mild ODS (17.36 ± 16.89 vs 36.38 ± 25.82, P = 0.0039). The risk of having severe symptoms was 4 times greater (odds ratio = 4.2, 95% confidence interval = 1.4 to 12.6, P = 0.01) among those with a high compression ratio (≥20%) after controlling for age, body mass index, and levator plate descent angle. Incomplete emptying was weakly, positively, linearly correlated with rectal hypermobility/folding (r = -0.2724, -0.3767 to 0.3922, and P = 0.0197, 0.0010, 0.0006, respectively). Women with more severe ODS experienced more rectal hypermobility/folding as measured via dynamic ultrasound-a cheaper, effective alternative to magnetic resonance defecography for evaluation of obstructed defecation.

Enhanced flight performance in non-uniformly flexible wings

The flexibility of biological propulsors such as wings and fins is believed to contribute to the higher performance of flying and swimming animals compared with their engineered peers. Flexibility seems to follow a universal design rule that induces bending patterns at about one-third from the distal tip of the propulsor’s span. However, the aerodynamic mechanisms that shaped this convergent design and the potential improvement in performance are not well understood. Here, we analyse the effect of heterogeneous flexibility on the flight performance (range and descent angle) of passively tumbling wings. Using experiments, numerical simulations, and scaling analysis, we demonstrate that spanwise tip flexibility that follows this empirical rule leads to improved flight performance. Improvement in flight range seems to be related to flutter-induced drag reduction. This mechanism is independent of the wing’s auto-rotation and represents a more general trait of wings with non-uniform tip flexibility.

Transperineal ultrasound of fetal head progression in prolonged labor: women\u2019s acceptance and ability to predict the mode of delivery

BackgroundDigital transvaginal examination of fetal head progression is subjective evaluation with many limitations. Using ultrasound (US) in the assessment of labor progression in prolonged labor is the current trend to predict the mode of delivery. The study intends to evaluate the women’s acceptance to the transperineal ultrasound (TPUS) compared with digital transvaginal examination, and its ability to predict the mode of delivery in prolonged labor. We included 28 pregnant ladies in a prolonged active phase of first or second stages of labor and followed them till delivery. TPUS was used to measure the fetal head–perineum distance (FHPD) and the angle of fetal head descent.ResultsOf the 28 participants, 53.5% of them delivered vaginally and 46.5% by Cesarean section (CS). All pregnant ladies described the TPUS as more convenient and less painful than digital vaginal examination. Cervical dilatation was negatively correlated with FHPD, and positively correlated with angle of fetal head descent. Both FHPD and angle of fetal head descent had a strong significant negative correlation. Using a cutoff value of 115° for the angle of fetal head descent, the positive predictive value (PPV) of vaginal delivery was 87%; using a cutoff value of 4.2 cm for FHPD, the PPV for vaginal delivery was 85%.ConclusionTPUS is more convenient, more accepted, and less painful than digital vaginal examination. Angle of head descent and FHPD are reliable predictors of the mode of delivery in prolonged labor.