Maximal Height Research Articles

PREDICTING MAXIMAL COUNTERMOVEMENT JUMP HEIGHT FROM UPRIGHT AND SQUAT POSITIONS HEAD TITLE: UPRIGHT AND SQUAT MAXIMUM JUMP HEIGHT PREDICTORS

Introduction. Countermovement jump is common in sport and testing and performed from various starting positions. Little is known about effective contributors to maximal countermovement jump height from various starting positions. Purpose and Objectives. Determine effective jump height predictors and effect of starting position on countermovement jump height. Applied Methodology. Forty-nine collegiate athletes performed maximal height countermovement jumps from upright and squatting positions with arm movement. Several variables were calculated from kinetic data. Correlation and regression determined variables related to and predictive of jump height in both conditions. Paired t-tests evaluated differences in jump height. Achieved Major Results. Upright condition jump height positively correlated with peak force and power, eccentric and concentric impulses, and countermovement depth. Jump height prediction included peak force and power, and eccentric and concentric impulses. Squat condition jump height positively correlated with peak force and power, mean rate of force development, force generated at the beginning of propulsion, and concentric impulse. Jump height prediction equation included mean rate of force development, force at the beginning of propulsion, and peak power. Jump height was higher in the upright condition. Conclusions. Higher jumps are achieved from the upright position. Peak force, peak power, and concentric and eccentric impulses best contribute to upright jump height. Mean rate of force development, force at the beginning of propulsion, and peak power best predicted squat jump height. Limitations. We did not restrict arm movement, to encourage natural motion. Depth was not controlled, rather advising a comfortable depth. Subjects were recruited from various collegiate sports. Practical implications. Maximal jump height from various positions may be achieved through efforts to maximize jump peak power and increase musculotendinous loading in sport-specific starting positions. Originality/Value. This is the first study to explore the predictors of upright and squat countermovement jumps. These results can guide jump performance training.

The Flattening Metallicity Gradient in the Milky Way’s Thin Disk

Abstract We calculate the ages, orbits and phase-space coordinates for a sample of ∼4 million LAMOST and Gaia stars. The ages are cross-matched and compared with values from two other popular age catalogs, which derive the ages using different methods. Of these ∼4 million stars, we select a sample of 1.3 million stars and investigate their radial metallicity gradients (as determined by orbital radii) as a function of their ages. This analysis is performed on various subsets of the data split by chemistry and orbital parameters. We find that commonly used selections for “thin disk” stars (such as low-α chemistry or vertically thin orbits) yield radial metallicity gradients that generally grow shallower for the oldest stars. We interpret this as a hallmark feature of radial migration (churning). Constraining our sample to very small orbital Z max (the maximal height of a star’s integrated orbit) makes this trend most pronounced. A chemistry-based “thin disk” selection of α-poor stars displays the same trend, but to a lesser extent. Intriguingly, we find that “thick disk” selections in chemistry and Z max reveal slightly positive radial metallicity gradients, which seem similar in magnitude at all ages. This may imply that the thick disk population is well mixed in age, but not in radius. This finding could help constrain conditions during the early epochs of Milky Way formation and shed light on processes such as the accretion and reaccretion of gases of different metallicities.

Lattice Paths With a First Return Decomposition Constrained by the Maximal Height of a Pattern

We consider the system of equations $A_k(x)=p(x)A_{k-1}(x)(q(x)+\sum_{i=0}^k A_i(x))$ for $k\geq r+1$ where $A_i(x)$, $0\leq i \leq r$, are some given functions and show how to obtain a close form for $A(x)=\sum_{k\geq 0}A_k(x)$. We apply this general result to the enumeration of certain subsets of Dyck, Motzkin, skew Dyck, and skew Motzkin paths, defined recursively according to the first return decomposition with a monotonically non-increasing condition relative to the maximal ordinate reached by an occurrence of a given pattern $\pi$.

MRI-based synthetic CT of the lumbar spine: Geometric measurements for surgery planning in comparison with CT

PurposeMRI is the imaging modality of choice for soft tissue-related spine disease. However, CT is superior to MRI in providing clear visualization of bony morphology. The purpose of this study is to test equivalency of MRI-based synthetic CT to conventional CT in quantitatively assessing bony morphology of the lumbar spine. MethodA prospective study with an equivalency design was performed. Adult patients who had undergone MRI and CT of the lumbar spine were included. Synthetic CT images were generated from MRI using a deep learning-based image synthesis method. Two readers independently measured pedicle width, spinal canal width, neuroforamen length, anterior and posterior vertebral body height, superior and inferior vertebral body length, superior and inferior vertebral body width, maximal disc height, lumbar curvature and spinous process length on synthetic CT and CT. The agreement among CT and synthetic CT was evaluated using equivalency statistical testing. ResultsThirty participants were included (14 men and 16 women, range 20–60 years). The measurements performed on synthetic CT of pedicle width, spinal canal width, vertebral body height, vertebral body width, vertebral body length and spinous process length were statistically equivalent to CT measurements at the considered margins. Excellent inter- and intra-reader reliability was found for both synthetic CT and CT. ConclusionsEquivalency of MRI-based synthetic CT to CT was demonstrated on geometrical measurements in the lumbar spine. In combination with the soft tissue information of the conventional MRI, this provides new possibilities in diagnosis and surgical planning without ionizing radiation.

Modelling and prevention of meshing interference in gear skiving of internal gears

Gear skiving is a highly productive process for machining of internal gears which are required in large quantity for electric mobility transmissions. Due to the complex kinematics of gear skiving, collisions of the tool and workpiece can occur during the process. Models exist to check for collisions of the tool shank or collisions in the tool run-out. While these models are sufficient for the process design of external gear skiving, at internal gears meshing interferences between tool and workpiece can appear outside the contact plane on the clearance face of the tool. To test for meshing interference requires comprehensive assessment of workpiece, tool and process kinematics. Currently, this is often done by time consuming CAD-simulation. In contrast, this paper presents an automated geometrical model for the analysis of meshing interference. The test for collisions is thereby performed along the whole height of the tool and especially includes constructive clearance angles and eccentric tool positions. The model is developed for user-friendly implementation and practical applications. The model for avoiding meshing interference in gear skiving is validated on two different process applications. In doing so, influences of the tool and process design on the interference situation are investigated, compared and discussed. Furthermore this new approach enables the prevention of meshing interference or tooth tip collisions in the early tool design by adjusting the process kinematics or the tool design itself. The maximal viable tool height can be quantified and recommendations for improving the clearance face situation are suggested.

Size Effect on the Reaction Rate of Surface Nanodroplets

Compartmentalizing reagents within small droplets is promising for highly efficient conversion and simplified procedures in many biphasic chemical reactions. In this work, surface nanodroplets (i.e., less than 100 nm in their maximal height) were employed to quantitatively understand the size effect on the chemical reaction rate of droplets. In our systems, a surface-active reactant in pure or binary nanodroplets reacted with the reactant in the bulk flow. Meanwhile, the product was removed from the droplet surface. The shrinkage rate of the nanodroplets was characterized by analyzing the lateral size as a function of time, where the droplet size was solely determined by the chemical reaction rate under a given flow condition for the transport of the reactant and the product. We found that the overall kinetics increases rapidly with the decrease in droplet’s lateral radius R, as dR/dt ∼ R–2. The faster increase in the concentration of the product in smaller droplets contributes to accelerating reaction kinetics. The enhancement of reaction rates from small droplet sizes was further confirmed when a nonreactive compound was present inside the droplets without reducing the concentrations of the reactant and the product on the droplet surface. The results of our study improve the understanding of chemical kinetics with droplets. Our findings highlight the effectiveness of small droplets for the design and control of enhanced chemical reactions in a broad range of applications.

Femoral plaque burden by ultrasound is a better indicator of significant coronary artery disease over ankle brachial index

The ankle-brachial index is a commonly used tool for identifying peripheral artery disease for cardiovascular risk stratification. An abnormal ankle-brachial index occurs only following extensive peripheral atherosclerosis occlusion, and thus has poor sensitivity for coronary atherosclerosis. There is a critical need for the development of tools that can detect risk prior to advanced stages of atherosclerosis. We sought to determine the sensitivity of femoral ultrasound for coronary artery disease. In this prospective, cross-sectional study, participants (n = 124) underwent ankle-brachial index measurement and femoral ultrasound for assessment of intima-media thickness, maximal plaque height, and total plaque area following coronary angiography. Receiver operating characteristic areas under the curve were plotted for identifying significant coronary artery disease (≥ 50% stenosis). Logistic regression was utilized to evaluate associations. 64% of participants had significant, angiography-confirmed coronary artery disease. Femoral ultrasound plaque area yielded the highest area under the curve for detecting significant coronary disease (area under the curve = 0.731). In contrast, an abnormal ankle-brachial index (≤ 0.90) produced an area under the curve of 0.568. Femoral ultrasound had a higher sensitivity (85%) than the ankle-brachial index (25%) for ruling out significant coronary artery disease. Both ankle-brachial index and femoral ultrasound have similar capacity to detect peripheral artery disease. Femoral ultrasound has a significantly greater discriminatory power than ankle-brachial index to detect clinically significant coronary artery disease. Ultrasound-captured femoral plaque burden directly delineates the extent of peripheral arterial disease and is better at ruling out significant coronary atherosclerosis than the ankle-brachial index.

Высокомасличная коллекция льна ФГБНУ ФНЦ ВНИИМК

The researches were conducted in the laboratory of oil flax breeding of the V.S. Pustovoit All-Russian Research Institute of Oil Crops, Krasnodar 2019– 2020. We studied the samples from the highly oleic collection of flax of the V.S. Pustovoit All-Russian Research Institute of Oil Crops in order to select the best ones for introduction into a breeding process to improve the existing varieties and develop new ones with a good combination of biological and economically valuable traits. The samples from our collection demonstrated variability by the general economically valuable and biological traits. Thus, difference in duration of a period emergence–maturing was from 10 to 12 days depending on year and weather conditions. Maximal plant height (63.3 сm) was noted in 2020, and minimal (38.0 cm) was similar in all years of the research. Seed yield per a plot varied from 32.5 to 112.5 g/m 2 in 2019 and from 30.0 to 175.0 g/m 2 in 2020. The highest yield (175.0 g/m2) was fixed in 2020, and minimal one (30.0 g/m2) was at the same level in all years of the research. The samples from the collection were differed by their oil content in seeds: from 44.6 to 48.7% in 2019 and from 44.8 to 49.3% in 2020. Variation of this trait by years was 4.1–4.5%, difference between years of the research was equal to 0.4%. The presence of variability in oil contents in seeds among samples from flax collection proves a possibility to conduct selections by this trait in all breeding nurseries of the laboratory. Thus, in 2020 we selected two samples with oil content in seeds more than 49.0%.

Cadaveric Study of Crista Fenestra: Revisited.

Objectives: Since there is great confusion in the literature about the anatomy and terms of the crista fenestra (CF) and the crista semilunaris, this paper is confined to the anatomy of the inferior margin of the round window (RW).Methods: This study was carried out on 20 cadaveric temporal bones. We measured the maximal height of the RW and the maximum height of the inferior bony edge of the RW, (termed CF type A), in this study. The ratio of the maximum height of CF type A to the maximum height of the RW was calculated. After drilling the CF type A, the scala tympani was visualized using a sialendoscope, and any bony projection in the inferior wall of the scala tympani just behind the round window membrane (RWM) was assessed and reported (termed CF B in this study).Results: We identified CF type A in 19/20 of cases (95%), and it was absent in only 1 case (5%). Its height ranged from 0.228 to 1.329 mm with an average of 0.604±0.347 mm. The percentage of CF type A to RW ranged from 19 to 75%, with an average of 42%. CF type B was present in only 2 specimens (10%).Conclusion: CF type A occupied a significant part of the RW in most specimens, and therefore its drilling was essential in a large percentage of cases. CF type B (inside the scala tympani) was present in 10% of the temporal bone samples, and curettage had to be done in these cases.

TAKE-OFF HIP EXTENSION ANGLE INFLUENCE ON THE TUCKED BACK SOMERSAULT PERFORMANCE

Back somersault is a basic element of gymnastics; its performance is strongly influenced by the take-off phase. The present work aimed to study how hip extension in the take-off of the tucked back somersault influences the velocity of rotation and the height of t h e somersault. To this end, we recorded a total of 60 somersaults by 4 gymnasts (i.e., 15 somersaults each). There were three groups of somersaults based on the instructions that were given to the gymnasts: no specific instruction, somersault as high as possible and rotate as fast as possible. The records were then analyzed in order to quantify the following variables: maximal height of the mass center and maximal body angular velocity during somersault, the hip angle and the knee angle at the take-off. Gymnasts seemed to be inclined to bend their knees rather than extend their hips in order to carry out the instruction.

On Hoffman’s t-values of maximal height and generators of multiple zeta values

We prove that any multiple t-value of maximal height (that is, all components of the index are greater than 1) can be written as a rational linear combination of multiple zeta values by using Glanois’s theorem. We also prove that each multiple zeta value is a $${\mathbb {Q}}$$ -linear combination of multiple t-values where all components of the index are 2 or 3. Further, we prove some results on multiple T-values, as conjectured by Kaneko–Tsumura.

Visual Scale as a Non-Invasive Method for Evaluation of Risk and Severity of Coronary Atherosclerosis.

Aim To evaluate quantitative and qualitative characteristics of atherosclerotic plaques (ASP) in carotid arteries (CA) and femoral arteries (FA) and to use these data for developing a visual scale (VS) for noninvasive diagnosis and determination of severity of coronary atherosclerosis.Material and methods This study included 216 patients (115 men and 101 women) aged 24 to 87 years (mean age, 61.5±10.73 years). All patients underwent coronary angiography (CAG) for detecting and determining severity of CA atherosclerosis and duplex scanning (DS) for detecting atherosclerosis of CA and FA.Results Analysis of ultrasound parameters of ASP in CA and FA showed that the maximal ASP height, moderate stenosis and maximal stenosis of the arterial bed had higher predictive values than other ultrasound parameters. These parameters were used for forming diagnostic complexes, on the basis of which two individual VSs for CA and FA were developed. Based on the high prognostic value of both scales, they were combined into one that was named VSCOMB. A ROC analysis determined cut-off points of the VSCOMB for diagnosis of CA atherosclerosis of various severity. VSCOMB scores >4 indicated pronounced CA atherosclerosis with sensitivity of 86.1 % and specificity of 87.5 % whereas VSCOMB scores ≤4 excluded it. Thus, VSCOMB score 0-1 indicated the absence of CA atherosclerosis; score 2-4 indicated the presence of subclinical CA atherosclerosis; and score >4 indicated severe CA atherosclerosis.Conclusion A VSCOMB was developed that includes a set of ultrasound parameters for CA and FA and is useful for noninvasive diagnosis of CA atherosclerosis of various severity. Simple and convenient use of VSCOMB allows it to be used at the screening stage to detect subclinical CA atherosclerosis and to prevent its progression.

Optimizing hydroponic culture media and NO3\u2212/NH4+ ratio for improving essential oil compositions of purple coneflower (Echinacea purpurea L.)

Medicinal plants represent a valuable commodity due to beneficial effects of their natural products on human health, prompting a need for finding a way to optimize/increase their production. In this study, a novel growing media with various perlite particle size and its mixture with peat moss was tested for hydroponic-based production of Echinacea purpurea medicinal plant under greenhouse conditions. The plant growth parameters such as plant height, total fresh leave weight, fresh root weight, total biomass, total chlorophyll, leaf area, and essential oil compositions were assessed. Perlite particle size in the growing media was varied from very coarse (more than 2 mm) to very fine (less than 0.5 mm), and the ratio between perlite and peat moss varied from 50:50 v/v to 30:70 v/v. In addition, two nitrate (NO3−) to ammonium (NH4+) ratios (90:10 and 70:30) were tested for each growing media. The medium containing very fine-grade perlite and 50:50 v/v perlite to peat moss ratio was found to be most optimal and beneficial for E. purpurea performance, resulting in maximal plant height, fresh and dry weight, leaf surface area, and chlorophyll content. It was also found that an increase in NO3−/NH4+ ratio caused a significant increase in plant growth parameters and increase the plant essential oil content. The major terpene hydrocarbons found in extract of E. purpurea with the best growth parameters were germacrene D (51%), myrcene (15%), α-pinene (12%), β-caryophyllene (11%), and 1-Pentadecene (4.4%), respectively. The percentages of these terpene hydrocarbons were increased by increasing of NO3−/NH4+ ratio. It can be concluded that decreasing the perlite particle size and increasing the NO3−/NH4+ ratio increased the plant growth parameters and essential oil compositions in E. purpurea.

Bijections Between Walks Inside a Triangular Domain and Motzkin Paths of Bounded Amplitude

This paper solves an open question of Mortimer and Prellberg asking for an explicit bijection between two families of walks. The first family is formed by what we name triangular walks, which are two-dimensional walks moving in six directions (0°, 60°, 120°, 180°, 240°, 300°) and confined within a triangle. The other family is comprised of two-colored Motzkin paths with bounded height, in which the horizontal steps may be forbidden at maximal height.
 We provide several new bijections. The first one is derived from a simple inductive proof, taking advantage of a 2n-to-one function from generic triangular walks to triangular walks only using directions 0°, 120°, 240°. The second is based on an extension of Mortimer and Prellberg's results to triangular walks starting not only at a corner of the triangle, but at any point inside it. It has a linear-time complexity and is in fact adjustable: by changing some set of parameters called a scaffolding, we obtain a wide range of different bijections.
 Finally, we extend our results to higher dimensions. In particular, by adapting the previous proofs, we discover an unexpected bijection between three-dimensional walks in a pyramid and two-dimensional simple walks confined in a bounded domain shaped like a waffle.

Photodynamic therapy as a treatment option for peripapillary pachychoroid syndrome: a pilot study.

To investigate the anatomical and functional results in eyes with peripapillary pachychoroid syndrome (PPS) undergoing photodynamic therapy (PDT). A total of 25 eyes from 23 patients with PPS treated with PDT were retrospectively evaluated in this multicentric study. Main outcome measure was the proportion of eyes that achieved treatment success, defined as a decrease in both subretinal fluid (SRF) height and central subfield thickness (CST), at 3 months after PDT compared to baseline. Secondary outcomes were the change in CST, SRF, and best-corrected visual acuity (BCVA) 3 months after treatment and predictive factors for treatment success. When available, data between 3 and 12 months were also reviewed. Treatment success was achieved in 16 eyes (64%). In the total cohort, CST decreased significantly from 356 ± 118 µm at baseline to 282 ± 90 µm and 270 ± 91 µm at 1 and 3 months, respectively (p < 0.001). Maximal SRF height decreased significantly from 102 ± 83 µm at baseline to 38 ± 46 µm and 32 ± 42 µm at 1 and 3 months, respectively (p < 0.001), and remained stable at month 6 (29 ± 44 µm) and month 12 (23 ± 35 µm). BCVA improved significantly from baseline to month 3 (p = 0.021). PDT can be considered an efficacious treatment option in patients with PPS. Prospective data with longer follow-up in a bigger cohort are needed in order to determine the optimal treatment algorithm in this relatively novel disease.

Chronic administration of caffeine alters acesulfame-K intake and features of fungiform taste buds in mice

The objective of this study was to investigate the effects of chronic administration of caffeine on the anatomical characteristics of taste buds, the expression level of taste receptor protein in mice, and preference for a palatable solution. We found that following a 21-day administration of caffeine, mice showed increased behavioural responses to sweet stimuli (acesulfame-K solution). Mirroring this behavioural change, chronic caffeine treatment evidently decreased the maximal cross-sectional area and height of the longitudinal axis of fungiform taste buds, the number of taste cells per fungiform taste bud, and the expression of G protein α-gustducin, while the expression of the sweet taste receptors T1R2 and T1R3 was reversed. Our findings demonstrate that chronic administration of caffeine has an impact on taste sensitivity and changes in taste bud features, which may contribute to the alteration of taste behaviour.

Histopathological analysis of the correlation between uveal melanomas and retinal tissue

AIM: To analyze the impacts of the shape of uveal melanoma on retinal structure. METHODS: Histopathological sections and clinical data from patients with uveal melanoma were retrospectively observed and analyzed, and key indicators including the tumor’s shape, size, height-to-base ratio, retinal thinning and retinal invasion were analyzed. RESULTS: The study included 102 patients (102 eyes) with a mean age of 45.6±12.4y, with 76 (75%) uveal melanomas showing the spindle cell type, 6 (6%) showing the epitheloid cell type, 16 (16%) showing the mixed cell type and 4 (4%) showing predominantly other cell types. Differentiated by tumor locations: 3 cases of ciliary body melanoma (2.9%), 28 cases of ciliary body and choroid melanoma (27.5%), 71 cases of choroid melanoma (69.6%). Retinal thinning was detected in 43 (43%) eyes and retinal invasion by the tumor cells in 86 (84%) eyes. Maximal tumor height ranged between 1.2 and 15.6 (mean: 8.3±3.6) mm, and mean maximal tumor base diameter was 17.3±6.5 (range: 4.8-31.2) mm. Mean R-value as ratio of tumor peak height to maximal tumor base diameter was 0.53±0.32. Mean R-value was significantly higher in the group with retinal thinning (n=43) than in the group without retinal thinning (n=59; 0.69±0.31 vs 0.42±0.27; P&lt;0.01). R-value was slightly, however statistically not significantly (P=0.09) higher in the group with retinal tumor invasion (n=86) than without retinal tumor invasion (n=16) (0.56±0.33 vs 0.41±0.25). CONCLUSION: A high R-value indicating a prominent tumor is associated with tissue thinning in the adjacent retina, and marginally significantly with intra-retinal tumor cell invasion. Shape of uveal melanomas’s corss section is of importance for the secondary involvement of the adjacent retina.

Prevalence and extent of mitral annular disjunction in structurally normal hearts: comprehensive 3D analysis using cardiac computed tomography.

Mitral annular disjunction is fibrous separation between the attachment of the posterior mitral leaflet and the basal left ventricular myocardium initially described in dissected hearts. Currently, it is commonly evaluated by echocardiography, and potential relationships with mitral valve prolapse and ventricular arrhythmia have been suggested. However, controversy remains as its prevalence and extent have not been fully elucidated in normal living subjects. Systolic datasets of cardiac computed tomography obtained from 98 patients (mean age, 69.1 ± 12.6 years; 81% men) with structurally normal hearts were assessed retrospectively. Circumferential extent of both mitral leaflets and disjunction was determined by rotating orthogonal multiplanar reconstruction images around the central axis of the mitral valvar orifice. Distribution angle within the circumference of the mitral valvar attachment and maximal height of disjunction were quantified. In total, 96.0% of patients demonstrated disjunction. Average distribution angles of the anterior and posterior mitral leaflets were 91.3 ± 9.4° and 269.8 ± 9.7°, respectively. Average distribution angle of the disjunction was 105.1 ± 49.2°, corresponding to 39.0 ± 18.2% of the entire posterior mitral valvar attachment. Median value of the maximal height of disjunction was 3.0 (1.5-7.0) mm. Distribution prevalence map of the disjunction revealed characteristic double peaks, with frequent sites of the disjunction located at the anterior to antero-lateral and inferior to infero-septal regions. Mitral annular disjunction is a rather common finding in the normal adult heart with bimodal distribution predominantly observed involving the P1 and P3 scallops of the posterior mitral leaflet.

Acacia gums new fractions and sparkling base wines: How their biochemical and structural properties impact foamability?

Foam is the first attribute observed when sparkling wine is served. Bentonite is essentially used to flocculate particles in sparkling base wines but can impair their foamability. Gums from Acacia senegal and Acacia seyal improved the foamability of different bentonite-treated base wines. Our main goal was to see how the supplementation with new fractions separated from Acacia gums by Ion Exchange Chromatography affected foamability of sparkling base wines, deepening the relation between foam behavior and characteristics of wine and gums. High molar mass fractions increased the maximal foam height and the foam height during the stability period in, respectively, 11 out and 8 out of 16 cases (69% and 50%, respectively). The properties of the supplementing gums fractions obtained by IEC and, although to a minor extent, the wine characteristics, affected positively and/or negatively the foam behavior. Wine foamability also depended on the relationship between wine and gums fractions properties.

Coating flows down a vertical fibre: towards the full Navier–Stokes problem

Abstract