Kinematic Study Research Articles

Tibial contact points cannot be used to determine internal-external axial rotation of the native tibiofemoral joint

BackgroundIn the study of tibiofemoral kinematics of the native knee, internal-external (IE) axial rotation is a motion of interest. Locations of contact by the femur on the tibia (termed tibial contact points) have been used to determine IE rotations but such rotations might not be useful due to large error. Hence, our objective was to determine whether tibial contact points are useful in quantifying IE rotations of the native knee. MethodFluoroscopic images of the native knee were analyzed from 25 subjects who performed a weight-bearing deep knee bend. For each subject, 3D bone + cartilage models were created. Following 3D model-to-2D image registration, anterior-posterior (AP) positions of the lowest points and the tibial contact points were computed for each femoral condyle at 0°, 30°, 60°, and 90° of flexion. IE rotations were the angles between lines connecting points in the medial and lateral tibial compartments at different flexion angles. ResultsBased on the lowest points, the tibia rotated internally on the femur primarily during the first 30° of flexion. In this range, mean internal tibial rotation based on tibial contact points was negligible but internal tibial rotation was significantly greater based on lowest points (0° vs 7°, p = 0.0002). At 90° of flexion, the difference was maintained (1.8° vs 8.3°, p = 0.0007). ConclusionWhile tibial contact points are useful in the study of wear of tibial inserts in total knee arthroplasty (TKA), tibial contact points considerably underestimate internal tibial rotation during flexion in the native knee and should not be used to quantify tibiofemoral kinematics.

JWST/NIRSpec insights into the circumnuclear region of Arp 220: A detailed kinematic study

The study of starburst and active galactic nuclei (AGN) feedback is crucial for understanding the regulation of star formation and the evolution of galaxies across cosmic time. Arp 220, the closest ultraluminous infrared galaxy (ULIRG), is in an advanced phase of a major merger with two distinct nuclei, and it shows evidence of multiphase (molecular, ionized, and neutral) and multiscale (from < 0.1 to > 5 kpc) outflows. Therefore, it represents an ideal system for investigating outflow mechanisms and feedback phenomena in detail. Using new JWST NIRSpec IFU observations, we investigated the spatially resolved gaseous (in both ionized and hot molecular phases) and stellar kinematics in the innermost 1 kpc. We decoupled the different gas kinematic components through multi-Gaussian fitting, identifying two multiphase outflows, each associated with one nucleus, with velocities up to $ We also resolved two counter-rotating discs around each nucleus embedded in a larger-scale rotational disk. We compute the total (including ionized, cold, and hot molecular) outflow mass ($ 10^7$ M$_ the mass rate ($ and the energetics ($ out for each nucleus, and we found that the ionized and hot molecular outflowing gas contribute around 2-30<!PCT!> of the total mass and the energy of the outflows, as inferred from the combination of multiwavelength information. We discuss the possible origin of the outflows, finding no compelling evidence to prefer a starburst- or AGN-driven scenario. Regardless of their nature, outflows in Arp 220 propagate in multiple directions from parsec to kiloparsec scales, potentially impacting a significant portion of the host galaxy. This contrasts with isolated systems where outflows typically follow a more collimated path or are limited to the central region of the galaxy and hence do not affect the interstellar medium throughout the entire galaxy. This study highlights the importance of investigating merging systems with multiwavelength facilities, including JWST/NIRSpec IFU, to obtain a comprehensive understanding of feedback mechanisms in galaxy evolution.

An in vivo three-dimensional, kinematics study of the cervical vertebrae under physiological loads in patients with cervical spondylosis

Background ContextStudies of in vivo kinematic differences between healthy individuals and those with cervical spondylosis (CS) have been reported, but only movements under non-physiological loads have been investigated. Differences in the in vivo, cervical kinematics between healthy individuals and those with CS are unknown. PurposeTo investigate the in vivo, cervical kinematics of patients with CS under physiological loads. Study DesignThis was a retrospective, case-controlled study that used three-dimensional (3D) to 3D registration techniques combined with conical beam computed tomography (CBCT) to investigate the cervical kinematics of patients with CS. Patient SampleTwenty individuals diagnosed with CS were selected for study participation and matched with 20 participants who did not have CS and were in good health. Outcome MeasuresPfirrmann grading,intervertebral range of motion(ROM), kinematics and cross-sectional area of posterior neck muscles(CAPNM). MethodsAll study participants underwent seven CBCT scans of their cervical vertebrae. The 3D segmental motion features of the vertebra in vivo were calculated using 3D-to-3D volume registration to overlay images of the vertebra at each functional position. The 3D range of motion (ROM) of each cervical segment was expressed with six degrees of freedom using Euler angles and translated onto a coordinate system. A kinematic subgroup analysis was conducted based on the severity of symptoms within the CS group, and differences in muscle volume between the CS and control groups were also evaluated. Project supported by the National Natural Science Foundation of China (Grant No. 81960408,82260445), Training plan for academic and technical leaders of major disciplines in Jiangxi Province(Grant No.20204BCJL22047), Clinical Cultivation Project of The First Affiliated Hospital of Nanchang University (Grant No.YFYLCYJPY 20220203).The authors declare no conflict of interest in preparing this article. ResultsThe CS group exhibited noticeable reductions in the primary rotational ROMs of left-right rotation at C4-C5, C5-C6, C6-C7, C4-C7, and C1-C7 compared to the controls. During left-right bending, there were no significant differences in the primary ROMs, coupled translations, or rotations between the two groups. However, compared to controls, the CS group had significantly lower primary ROMs for C4 C7, C1-C7 and C5-C6 during flexion-extension. During left-right rotation, the primary rotations and coupled lateral bending at C6-C7 were significantly increased in the mild CS group compared to the moderate CS group. In the mild CS group, the primary ROM of the C4-C5 and C5-C6 during flexion-extension was significantly greater than that of the moderate CS group. ConclusionsFor the first time, the in vivo 3D kinematics of the cervical spine during head movement under physiological load in CS individuals have been adequately described and compared with healthy cervical vertebrae, which can be used as a reference point for future studies. The application of CBCT helps to obtain accurate and precise movement information of CS patients and effectively enhance the evaluation results obtained from imaging information.

A kinematical study of the launching region of the blueshifted HH 46/47 outflow with SINFONI K-band observations

Studying outflows is important, as they may significantly contribute to angular momentum removal from a star-disc system and thus affect disc evolution and planet formation. To investigate the different outflow components, including the collimated jet, wide-angled molecular outflow, and outflow cavity, of the Class I HH 46/47 outflow system, we focused on their kinematics. We present near-infrared (NIR) K-band integral field observations of the blueshifted HH 46/47 outflow base obtained using VLT/SINFONI with an angular resolution of 0 Our analysis focuses on Fe ii H$_2$ 1–0 S(1), and Br-gamma emission. We employed a wavelength recalibration technique based on OH telluric lines in order to probe the kinematics of the wide-angled flow with an accuracy of sim 1 km s$^ $ - 3 km s$^ We confirmed a velocity gradient of sim 10 km s$^ $ transverse to the outflow direction in the wide-angled H$_2$ outflow cavity. We find that the H$_2$ cavity peaks at radial velocities of sim $-$15 km s$^ $ to $-$30 km s$^ $, and that the atomic jet peaks at $v_ rad $ sim $-$210 km s$^ $. The outflow exhibits a layered structure: The high-velocity Fe ii and Br-gamma jet is surrounded by a wide-angled H$_2$ outflow cavity that is in turn nested within the continuum emission and CO molecular outflow. The continuum emission and H$_2$ outflow cavity are asymmetric with respect to the jet axis. We propose that the origin of the asymmetries and the velocity gradient detected in the wide-angled H$_2$ cavity is due to a wide-angled outflow or successive jet bowshocks expanding into an inhomogeneous ambient medium or the presence of a secondary outflow. We eliminated outflow rotation as an exclusive origin of this velocity gradient due to large specific angular momenta values, $J(r)$ approx 3000 - 4000 km s$^ \,$au, calculated from 1 to 2 along the outflow and the fact that the sense of apparent rotation we detected is opposite to that of the CO envelope emission. The observations reveal the complexities inherent in outflow systems and the risk of attributing transverse velocity gradients solely to rotation.

UVIT Study of the MAgellanic Clouds (U-SMAC). II. A Far-UV Catalog of the Small Magellanic Cloud: Morphology and Kinematics of Young Stellar Population

The Small Magellanic Cloud (SMC) is an irregular dwarf galaxy that has recently undergone an interaction with the Large Magellanic Cloud. The young massive stars in the SMC formed in the disturbed low-metallicity environment are important targets in astrophysics. We present a catalog of ∼76,800 far-ultraviolet (FUV) sources toward the SMC detected using the Ultra Violet Imaging Telescope onboard AstroSat. We created an FUV catalog with ∼62,900 probable SMC members which predominantly comprise main-sequence, giant, and subgiant stars. We selected four young populations (Young 1, Young 2, Young 3, and Blue Loop (BL) stars) identified from the Gaia optical color–magnitude diagram to study the morphology and kinematics of the young SMC using this catalog. We detect a clumpy morphology with a broken bar, a shell-like structure, and the inner SMC Wing for the four stellar populations. The eastern region and the northeastern regions are mainly populated by Young 1, 2, and 3 stars. The central region predominantly has the Young 2 and 3 populations, whereas the SW has BL stars, and Young 2 and 3 stars. The 2D kinematic study using proper motion (PM) reveals that Young 2 and 3 populations show two kinematically distinct subpopulations with low and high PM dispersion, whereas the Young 1 and BL stars show two kinematically distinct populations with low dispersion. Our analysis points to a kinematic disturbance along the R.A. direction for stars younger than ∼150 Myr located in the eastern region, with no significant disturbance along the decl.

Kinematical signatures: Distinguishing between warps and radial flows

Increasing evidence shows that warped disks are common, challenging the methods used to model their velocity fields. Molecular line emission of these disks is characterized by a twisted pattern, similar to the signal from radial flows, complicating the study of warped disk kinematics. Previous attempts to model these features have encountered difficulties in distinguishing between the underlying kinematics of different disks. This study aims to advance gas kinematics modeling capabilities by extending the Extracting Disk Dynamics ( eddy ) package to include warped geometries and radial flows. We assess the performance of eddy in recovering input parameters for scenarios involving warps, radial flows, and combinations of the two. Additionally, we provide a basis to break the visual degeneracy between warped disks and radial flow, establishing a criterion to distinguish them. We extended the eddy package to handle warped geometries by including a parametric prescription of a warped disk and a ray-casting algorithm to account for the surface self-obscuration arising from the 3D to 2D projection. The effectiveness of the tool was tested using the radiative transfer code RADMC3D generating synthetic models for disks with radial flows, warped disks, and warped disks with radial flows. We demonstrate the efficacy of our tool in accurately recovering the geometrical parameters of systems, particularly in data with sufficient angular resolution. Importantly, we observe minimal impact from thermal noise levels typical in Atacama Large Millimeter/submillimeter Array (ALMA) observations. Furthermore, our findings reveal that fitting an incorrect model type produces characteristic residual signatures, which serve as kinematic criteria for disk classification. Characterizing gas kinematics requires careful consideration of twisted motions. While our model provides insights into disk geometries, caution is needed when interpreting parameters in regions with complex kinematics or low-resolution data. Future ALMA baseline observations should help clarify warped disk kinematics.

Analysis of the third class mechanism using the modeling method in the Mathcad software environment

Purpose. To carry out a kinematic analysis of a flat twelve-link hinged mechanism with three leading links, the basis of which is a structural group of links of the third class of the fourth order with rotational kinematic pairs, which is used in technological equipment. Methodology. The kinematic study of a flat complex mechanism of the third class with three leading links was performed using the mathematical modeling method in the Mathcad software environment. Findings. Using the method of mathematical modeling, the mechanism was presented in the form of free vectors built on its links, for which, taking into account the presence of three leading links, three vector contours were selected, which made it possible to draw up a system of vector equations of their closedness with further solving by a numerical method in the Mathcad software environment. The functions of the rotation angles of the mechanism links, their angular velocities and accelerations were obtained in analytical and graphical form depending on the rotation angle of the first driving crank of the mechanism, the calculation of the angular velocities and accelerations of all the driven links of the mechanism was performed. Originality. A sequence was developed and a kinematic study of a complex planar mechanism of the third class with three leading links was done, the basis of which is a structural group of links of the third class of the fourth order. Schematic modeling of the mechanism with three leading links was performed, a visualization schedule of its kinematic scheme was built, and a valid version of its assembly was obtained from many possible ones, for which the values of kinematic parameters of all its links were determined. Practical value. An analysis of the effect of the kinematic parameters of the three leading links of the third-class mechanism on the movement of the working body of the technological equipment was carried out. From the analysis of the obtained research results for the cycle of the mechanism the reason was found for the incomplete technological stoppage of the link, which should provide the working body of the machine for the required period of time. Recommendations of the elimination were made to identify the deficiency and proposals for the need to improve the drive of this equipment.

Acoustic Analysis of Spatiotemporal Variability in Children With Childhood Apraxia of Speech.

The purpose of this study was to investigate acoustic spatiotemporal variability in children with childhood apraxia of speech (CAS) compared to children with typical development (TD). Increased spatiotemporal variability in children with CAS relative to nonapraxic peers has been documented in multiple kinematic studies. To date, few studies have investigated spatiotemporal variability in CAS using an acoustic signal. Data were drawn from 10 children with CAS and 10 children with TD, ranging in age from 5;0 to 11;2 (years;months), who participated in an online study. All children with CAS had a verified diagnosis and showed at least five CAS features across at least two tasks, independently confirmed by two speech-language pathologists with expertise in CAS. Children repeated the sentences "Buy Bobby a puppy" (BBAP) and "Mom pets the puppy" (MPP) 10 times each. The acoustic spatiotemporal index (STI), calculated from the amplitude envelope, was used to investigate acoustic spatiotemporal variability. Using a regression analysis, we analyzed group differences in STI values while controlling for age and gender. Children with CAS did not produce enough usable tokens of BBAP to analyze. MPP revealed significantly higher acoustic STI values in children with CAS compared to children with TD. No significant effects were observed for age or gender. Acoustic data collected online without the use of specialized equipment yielded high-quality audio data from which amplitude envelope tracing could be reliably accomplished. This study adds to a growing body of empirical data indicating that children with CAS produce speech with more variable spatiotemporal control compared to children with TD. In addition to producing more variable speech, children with CAS were less consistently able to form productions free of phonetic errors. These findings also demonstrate the feasibility of using remote data collection to investigate acoustic spatiotemporal variability, which allows for the recruitment of larger samples of low-incidence populations. https://doi.org/10.23641/asha.26814883.

Observational signatures of circumbinary discs II: Kinematic signatures in velocity residuals

Abstract Kinematic studies of protoplanetary discs are a valuable method for uncovering hidden companions. In the first paper of this series, we presented five morphological and kinematic criteria that aid in asserting the binary nature of a protoplanetary disc. In this work we study the kinematic signatures of circumbinary discs in the residuals of their velocity maps. We show that Doppler-flips, spiral arms, eccentric gas motion, fast flows inside of the cavity, and vortex-like kinematic signatures are commonly observed. Unlike in the planetary mass companion case, Doppler-flips in circumbinary discs are not necessarily centred on a companion, and can extend towards the cavity edge. We then compare the kinematic signatures in our simulations with observations and see similarities to the Doppler-flip signal in HD 100546 and the vortex-like kinematic signatures in HD 142527. Our analysis also reveals kinematic evidence for binarity in several protoplantary disks typically regarded as circumstellar rather than circumbinary, including AB Aurigae and HD 100546.

REBELS-25: discovery of a dynamically cold disc galaxy at z = 7.31

ABSTRACT We present high-resolution ($\sim 0.14$ arcsec = 710 pc) Atacama Large Millimetre/submillimetre Array [C ii] 158 $\mu$m and dust continuum follow-up observations of REBELS-25, a [C ii]-luminous ($L_{\mathrm{[CII]}}=(1.7\pm 0.2)\times 10^9\, \mathrm{L_{\odot }}$) galaxy at redshift $z=7.3065\pm 0.0001$. These high-resolution, high signal-to-noise observations allow us to study the sub-kpc morphology and kinematics of this massive ($M_* = 8^{+4}_{-2} \times 10^9 \mathrm{{\rm M}_{\odot }}$) star-forming (SFR$_{\mathrm{UV+IR}} = 199^{+101}_{-63} \mathrm{{\rm M}_{\odot }} \mathrm{yr}^{-1}$) galaxy in the Epoch of Reionization. By modelling the kinematics with $^{\mathrm{3D}}$BAROLO, we find it has a low-velocity dispersion ($\bar{\sigma } = 33^{+9}_{-7}$ km s$^{-1}$) and a high ratio of ordered-to-random motion ($V_{\mathrm{rot, ~max}}/\bar{\sigma } = 11 ^{+6}_{-5}$), indicating that REBELS-25 is a dynamically cold disc. Additionally, we find that the [C ii] distribution is well fit by a near-exponential disc model, with a Sérsic index, n, of $1.3 \pm 0.2$, and we see tentative evidence of more complex non-axisymmetric structures suggestive of a bar in the [C ii] and dust continuum emission. By comparing to other high spatial resolution cold gas kinematic studies, we find that dynamically cold discs seem to be more common in the high-redshift Universe than expected based on prevailing galaxy formation theories, which typically predict more turbulent and dispersion-dominated galaxies in the early Universe as an outcome of merger activity, gas accretion, and more intense feedback. This higher degree of rotational support seems instead to be consistent with recent cosmological simulations that have highlighted the contrast between cold and warm ionized gas tracers, particularly for massive galaxies. We therefore show that dynamically settled disc galaxies can form as early as 700 Myr after the big bang

Didactical proposal for the study of rigid body kinematics using analytical, video-tracking, and simulated cases of a four-bar mechanism

This work used three methods (analytical, simulated, and video-tracking) to analyze the kinematics of a four-bar mechanism. The results obtained were shared and implemented in an engineering dynamics course at the university level to assess the impact of this exercise on motivation and understanding of the course topic. A survey was used to evaluate the exercise. The survey results showed that for the students, the implementation of different methods to tackle the same problem improved their understanding of the concepts and gave them other options for analyzing a mechanical system.

Extragalactic globular cluster near-infrared spectroscopy

Context. One way to constrain the evolutionary histories of galaxies is to analyse their stellar populations. In the local Universe, our understanding of the stellar population properties of galaxies has traditionally relied on the study of optical absorption and emission-line features. Aims. In order to overcome limitations intrinsic to this wavelength range, such as the age-metallicity degeneracy and the high sensitivity to dust reddening, we must use wavelength ranges beyond the optical. The near-infrared (NIR) offers a possibility to extract information on spectral signatures that are not as obvious in traditional optical bands. Moreover, with the current and forthcoming generation of instrumentation focusing on the NIR, it is mandatory to explore possibilities within this wavelength range for nearby-Universe galaxies. However, although the NIR shows great potential, we are only beginning to understand it. Widely used techniques such as a full spectral fitting and line strength indices need to be tested on systems that are as close to simple stellar populations as possible, and the result from the techniques need to be compared to the yields from a traditional optical analysis. Methods. We present a NIR spectral survey of extragalactic globular clusters (GCs). The set was composed of 21 GCs from the Centaurus A galaxy that were obtained with SOAR/TripleSpec4, which covered the ∼1.0–2.4 μm range with a spectral resolution (R = λ/Δλ) of 3500. These spectra cover Hβ equivalent widths between 0.98 Å and 4.32 Å, and [MgFe]′ between 0.24 Å and 3.76 Å. Results. This set was ideal for performing absorption band measurements and a full spectral fitting, and it can be used for kinematic studies and age and abundance measurements. With this library, we expect to be able to probe the capabilities of NIR models, as well as to further improve stellar population estimates for the GCs around the Centaurus A galaxy.

Flap and Wing Dynamics for a Light Sport Aircraft Analysis Using a Topological Model

This paper presents a more general method to study the dynamic behavior of a planar mechanism with joints. To do this, Graph Theory is used. A topological description is presented based on which a corresponding graph is attached to any mechanism. This method can be used for both kinematic and dynamic study in the same model, and many of the descriptors used in kinematic analysis can also be used for dynamic analysis. As a final result, the motion equations of the studied mechanical system can be obtained. An application is made to a flap and wing control system of a light sport aircraft. The graph associated with the mechanism first used to determine the field of velocities and accelerations of the mechanism elements is then used to obtain the motion equation for the control system. In this way, Graph Theory proves useful for the parallel study of both the kinematic and dynamic study of such problems.

Kinematic study of the orion complex: Analysing the young stellar clusters from big and small structures

Abstract In this work, we analysed young stellar clusters with spatial and kinematic coherence in the Orion star-forming complex. For this study, we selected a sample of pre-main sequence candidates using parallaxes, proper motions and positions on the colour-magnitude diagram. After applying a hierarchical clustering algorithm in the 5D parameter space provided by Gaia DR3, we divided the recovered clusters into two regimes: Big Structures and Small Structures, defined by the number of detected stars per cluster. In the first regime, we found 13 stellar groups distributed along the declination axis in the regions where there is a high density of stars. In the second regime, we recovered 34 clusters classified into two types: 14 as small groups completely independent from the larger structures, including four candidates of new clusters, and 12 classified as sub-structures embedded within five larger clusters. Additionally, radial velocity data from APOGEE-2 and GALAH DR3 was included to study the phase space in some regions of the Orion complex. From the Big Structure regime, we found evidence of a general expansion in the Orion OB1 association over a common centre, giving a clue about the dynamical effects the region is undergoing. Likewise, in the Small Structure regime, the projected kinematics shows the ballistic expansion in the λ Orionis association and the detection of likely events of clusters’ close encounters in the OB1 association.

Truncated cones from indenting a clamped disk.

When a simply supported thin disk is indented by a centrally applied point force, it buckles out-of-plane to form a shape dominated by two conical portions: a uniform region indenting against the support, interrupted by a smaller elevated portion detached from the support, altogether known as a "developable cone" or d-Cone. If a central circular region of the disk is clamped instead, then the buckling complexion changes markedly: The indenting region is interspersed with several detached and elevated cones, now "truncated," where their number depends on the clamping extent as well as the radius of the circular simple support. Studies of d-Cone kinematics often consider its shape as an analogous vertex, which forms by folding along hinge lines separating triangular facets. We extend this methodology by, first, showing that each truncated cone, or "t-Cone," operates as a pair of connected d-Cone vertices that fold synchronously and that their number, viz. distribution, around the indented disk stems from optimal "packaging" of the folded shape in the annular space between the clamping edge and support; furthermore, because our analysis presumes a geometrically dominant character, it captures the "saturated," i.e., final number of t-Cones, in experiments from a recent study. Our predictions agree rather well.

Predicting action type from visual perception: a kinematic study.

Predicting action type from visual perception: a kinematic study.

Neural correlates of bradykinesia in Parkinson’s disease: a kinematic and functional MRI study

Bradykinesia is defined as a “complex” of motor alterations including decreased movement amplitude and/or speed and tendency to reduce them with movement repetition (sequence effect). This study aimed at investigating the neural and kinematic correlates of bradykinesia during hand-tapping in people with Parkinson’s disease (pwPD) relative to healthy controls. Twenty-five pwPD and 25 age- and sex-matched healthy controls underwent brain functional MRI (fMRI) during a hand-tapping task: subjects alternatively opened and closed their right hand as fully and quickly as possible. Hand-tapping kinematic parameters were objectively measured during the fMRI task using an optical fibre glove. During the fMRI task, pwPD showed reduced hand-tapping amplitude (hypokinesia) and a greater sequence effect. PwPD relative to healthy controls showed a reduced activity of fronto-parietal areas, middle cingulum/supplementary motor area (SMA), parahippocampus, pallidum/thalamus and motor cerebellar areas. Moreover, pwPD showed an increased activity of brain cognitive areas such as superior temporal gyrus, posterior cingulum, and cerebellum crus I. The decreased activity of cerebellum IV–V–VI, vermis IV–V, inferior frontal gyrus, and cingulum/SMA correlated with hypokinesia and with the sequence effect. Interestingly, a reduced activity of areas involved in motor planning and timing correlated both with hypokinesia and with the sequence effect in pwPD. This study has the major strength of collecting objective motor parameters and brain activity simultaneously, providing a unique opportunity to investigate the neural correlates of the “bradykinesia complex”.

Standing Long Jump Performance Is Enhanced When Using an External as Well as Holistic Focus of Attention: A Kinematic Study.

Standing long jump is known as one of the important skills in the success of athletes in most sports. In addition, one of the most effective factors that can affect standing long jump distance and kinematics is the focus of attention used by the athlete. Therefore, the aim of the present study was to compare the effect of internal, external, and holistic focus of attention instructions on standing long jump performance and kinematics. The participants were 30 novices (all males; mean age = 21.70 ± 2.21 years; mean height = 175.73 ± 6.09 cm; and mean weight = 73.76 ± 11.77 kg) who performed 12 standing long jumps in four focus of attention conditions. Internal focus, external focus, holistic focus, and control conditions were implemented in a counterbalanced order. Jump distance and maximum knee flexion angle before take-off were recorded in all trials. The results showed that in relation to the standing long jump performance, the distance was similar in external and holistic focus conditions, and both were superior to internal or control conditions. There was no difference between control and internal focus of attention conditions. The results related to movement kinematics, however, did not report a difference between the maximum flexion angles before take-off. This study replicates the benefits of external and holistic focus instructions for jump distance, but this difference was not a product of different maximum knee flexion angles. It is suggested that coaches implement external and/or holistic focus cues to maximize athlete performance in jumping tasks.

An Example of Intracontinental Cross Faults Formation from the Vicinity of Karapınar (Konya – Central Anatolia)

Karapınar (Konya, Turkey) is located in the central part of the Anatolian micro-plate which is characterized by differently oriented Neogene–Quaternary horst – graben structures. The basement of the region is composed of Mesozoic–Paleogene rocks. In the various Neogene basins, Miocene–Pliocene sedimentary and volcanic rocks overlie the basement rocks and form the secondary rock units. The youngest units are Plio-Quaternary aged terrestrial sediments and volcanics. The main structure of the study area consists of WNW-ESE and NE-SW trending intersecting graben-horst structures and the normal faults forming them. The approximately WNWESE trending basins are filled with Miocene–Pliocene sediments, while the NE-SW trending basins are filled with Pliocene–Quaternary sediments. Kinematic studies show that the faults in the study area are developed in all directions and the distribution of the slicken lines indicates that there is multidirectional crustal extension. The principal stress axes obtained from all the kinematic data show that σ1 is nearly vertical, σ2 and σ3 are horizontal. If all faults are assumed to have been formed due to the same stress system, the study area is predominantly elongated in the NW-SE direction. However, detailed field observations and structural analyses indicate that the NE-SW trending fault systems are younger than the WNW-ESE trending faults. This indicates that firstly NNE-SSW and then NW-SE crustal extension developed in the study area respectively.

Gas-rich "ultra-diffuse" galaxies are consistent with the baryonic Tully-Fisher relation and with Milgromian dynamics

Some gas-rich ``ultra-diffuse'' galaxies (UDGs), which are extreme examples of low surface brightness (LSB) dwarf galaxies, have been reported to lack dark matter and to be offset from the baryonic Tully-Fisher relation (BTFR). If confirmed, these UDGs would represent a serious challenge for both Lambda CDM galaxy-formation models and Milgromian dynamics. Here I demonstrate that these conclusions are very dubious due to underestimated uncertainties on inclinations and/or distances. First, I show that UDGs are offset from the BTFR in the same way as usual face-on LSB dwarfs due to systematic biases at low inclinations. Next, I analyze the two UDGs with the best available rotation-curve data. The first (AGC\,242019) is ideally inclined for kinematic studies; MOND can fit the observed rotation curve with a distance of 12.5pm 0.6 Mpc, which is consistent with Virgocentric flow models. The second UDG (AGC\,114905) is close to face-on, so not ideal for kinematic studies; MOND can fit the observed rotation curve with a distance of 68pm 13 Mpc and inclination of circ circ $, which are consistent with existing data. In particular, I show that the disk inclination is more uncertain than previously estimated due to significant asymmetries (lopsidedness) in the stellar distribution. In conclusion, there is no strong evidence that gas-rich UDGs and gas-rich LSB dwarfs are distinct galaxy populations with different dynamical properties; instead, UDGs seem to be a subset of LSB dwarf galaxies biased toward face-on systems.