Effects of 8-weeks of stable vs unstable surface destabilizing training on shot outcome in elite golfers (Efectos de 8 semanas de entrenamiento desestabilizador en superficies estables vs inestables sobre el resultado de los golpes en golfistas de élite)

Purpose: This research aimed to compare the effect of two intervention programs using stable or unstable surfaces on speed and hitting distance in golf stroke/swing. Methods: Twenty-five elite golfers (19.20 ± 1.77 years, height = 181.12 ± 4 cm, body mass = 75.35 ± 5.83; kg, BMI = 22.71 ± 1.76 kg.m2, handicap: 2.49 ± 2.56) were randomly assigned to two different 8-week training programs based on unstable surface (n = 12) or stable surface training (n=13). Measurements of carry distance and club head speed were performed using the Trackman Golf® system, with each participant executing five swings and obtaining the average and best distance. Results: No significant changes (p< 0.05) in the club head speed or carry distance were found after the intervention in the stable surface or the unstable surface training group. Conclusions: The proposed intervention using instability surfaces does not provide any additional benefit to training on stable surfaces in the specific performance of the stroke in elite golfers. Resumen. Objetivo: Esta investigación tuvo como objetivo comparar el efecto de dos programas de intervención que utilizan superficies estables o inestables sobre la velocidad y la distancia de golpeo en el golpeo/swing de golf. Métodos: Veinticinco golfistas de élite (19,20 ± 1,77 años, altura = 181,12 ± 4 cm, peso corporal = 75,35 ± 5,83; kg, IMC = 22,71 ± 1,76 kg.m2, hándicap: 2,49 ± 2,56) fueron asignados aleatoriamente a dos programas de entrenamiento diferentes de 8 semanas de duración basados en superficies inestables (n = 12) o en superficies estables (n = 13). Las mediciones de la distancia de golpeo y la velocidad de la cabeza del palo se realizaron con el sistema Trackman Golf®, ejecutando cada participante cinco swings y obteniendo la media y la mejor distancia. Resultados: No se encontraron cambios significativos (p< 0,05) en la velocidad de la cabeza del palo ni en la distancia de golpeo después de la intervención en el grupo de entrenamiento en superficie estable o en el de superficie inestable. Conclusiones: La intervención propuesta utilizando superficies de inestabilidad no aporta ningún beneficio adicional al entrenamiento en superficies estables en el rendimiento específico del golpe en golfistas de élite.

Additive Manufacturing of Tungsten Carbide Surfaces with Extreme Wear Resistivity

Steel surfaces have been coated with Co-based tungsten carbide (WC) in an additive printing process. This process leads to compact and extremely mechanically stable surfaces. We performed tribological measurements using WC counter bodies under dry conditions and severe mechanical load. Low coefficients of friction, even for rough surfaces, were found and the resulting wear rates were extraordinarily small, even when compared to high-quality PVD film with a similar composition. These findings suggest a wide field of application for this novel preparation process for wear-resistive surfaces.

ℤ3-actions on Horikawa surfaces

Minimal algebraic surfaces of general type [Formula: see text] such that [Formula: see text] are called Horikawa surfaces. In this note, [Formula: see text]-actions on Horikawa surfaces are studied. The main result states that given an admissible pair [Formula: see text] such that [Formula: see text], all the connected components of Gieseker’s moduli space [Formula: see text] contain surfaces admitting a [Formula: see text]-action. On the other hand, the examples considered allow us to produce normal stable surfaces that do not admit a [Formula: see text]-Gorenstein smoothing. This is illustrated by constructing non-smoothable normal surfaces in the KSBA-compactification [Formula: see text] of Gieseker’s moduli space [Formula: see text] for every admissible pair [Formula: see text] such that [Formula: see text]. Furthermore, the surfaces constructed belong to connected components of [Formula: see text] without canonical models.

I-surfaces with one T-singularity

We classify normal stable surfaces with $$K_X^2 = 1$$ K X 2 = 1 , $$p_g = 2$$ p g = 2 and $$q=0$$ q = 0 with a unique singular point which is a non-canonical T-singularity, thus exhibiting two divisors in the main component and a new irreducible component of the moduli space of stable surfaces $${{\overline{{{\mathfrak {M}}}}}}_{1,3}$$ M ¯ 1 , 3 .

Autonomous Repeat Image Feature Tracking (autoRIFT) and Its Application for Tracking Ice Displacement

In this paper, we build on past efforts with regard to the implementation of an efficient feature tracking algorithm for the mass processing of satellite images. This generic open-source feature tracking routine can be applied to any type of imagery to measure sub-pixel displacements between images. The routine consists of a feature tracking module (autoRIFT) that enhances computational efficiency and a geocoding module (Geogrid) that mitigates problems found in existing geocoding algorithms. When applied to satellite imagery, autoRIFT can run on a grid in the native image coordinates (such as radar or map) and, when used in conjunction with the Geogrid module, on a user-defined grid in geographic Cartesian coordinates such as Universal Transverse Mercator or Polar Stereographic. To validate the efficiency and accuracy of this approach, we demonstrate its use for tracking ice motion by using ESA’s Sentinel-1A/B radar data (seven pairs) and NASA’s Landsat-8 optical data (seven pairs) collected over Greenland’s Jakobshavn Isbræ glacier in 2017. Feature-tracked velocity errors are characterized over stable surfaces, where the best Sentinel-1A/B pair with a 6 day separation has errors in X/Y of 12 m/year or 39 m/year, compared to 22 m/year or 31 m/year for Landsat-8 with a 16-day separation. Different error sources for radar and optical image pairs are investigated, where the seasonal variation and the error dependence on the temporal baseline are analyzed. Estimated velocities were compared with reference velocities derived from DLR’s TanDEM-X SAR/InSAR data over the fast-moving glacier outlet, where Sentinel-1 results agree within 4% compared to 3–7% for Landsat-8. A comprehensive apples-to-apples comparison is made with regard to runtime and accuracy between multiple implementations of the proposed routine and the widely-used “dense ampcor" program from NASA/JPL’s ISCE software. autoRIFT is shown to provide two orders of magnitude of runtime improvement with a 20% improvement in accuracy.

Morphological evolution of carbonated hydroxyapatite to faceted nanorods through intermediate states

On the conversion of a parent calcite nanocrystal, thin low-crystalline nanosheets of carbonated hydroxyapatite are initially grown via the dissolution–reprecipitation route and then evolve into faceted rods covered with stable surfaces.

A Stable Biotin-Streptavidin Surface Enables Multiplex, Label-Free Protein Detection by Aptamer and Aptamer-Protein Arrays Using Arrayed Imaging Reflectometry

While label-free multiplex sensor technology enables “mixing and matching” of different capture molecules in principle, in practice this has been rarely (if ever) demonstrated. To fill this gap, we developed protocols for the preparation of mixed aptamer-protein arrays on the arrayed imaging reflectometry (AIR) sensing platform using streptavidin as a common attachment point for both biotinylated proteins and aptamers. Doing so required overcoming the noted instability of dried streptavidin monolayers on surfaces. After characterizing this degradation, stable surfaces were obtained using a commercial microarray product. Microarraying through the layer of stabilizer then provided mixed aptamer-antibody arrays. We demonstrate that sensor arrays prepared in this manner are suitable for several probes (thrombin and TGF-β1 aptamers; avi-tagged protein) and targets.

Temporary analysis of land use changes in Pine and mixed forests in Mexico

Objective: to evaluate the changes in land use that occurred in Pine and mixed forests, at the national level during the period 2001 to 2013.Design/Methodology/Approach: layers of Land Use and Vegetation (Sp. equ. USV) of Series II (from 2001) and V (from 2013) of the Instituto Nacional de Estadística y Geografía, scale 1: 250,000 were used. Different categories of vegetation under study were reclassified and homogenized for both covers. Rates of change and indicators of transitions were estimated for the spatial-temporary analysis: surfaces of estimated losses and gains, indices of persistence, exchanges and net changes; also, indices of gain and loss to persistence.Results: the rate of negative change for primary forests (Pine and mixed) ranges from 0.80 to 1.84. It was observed that 120 047 km2 (57.72%) were stable surfaces. However, 36 986 km2 (18.00%) were losses, 14 369 km2 gains and 28 738 km2 (14.00%) between categories. It was observed from 2001 to 2013 that 13.69% of the area corresponding to primary forests which existed in 2001 became part of secondary vegetation in 2013.Study limitations/Implications: in order to observe the influence of other categories, it would be important to incorporate more classes throughout the study to be analyzed globally in the system throughout the country.Findings/Conclusions: The persistence of the coverage of primary forests is important to design conservation policies