70 research outputs found

    Determination of Biomechanical Differences Between Elite and Novice San Shou Female Athletes

    Get PDF
    Determining the key factors in athletic performance is important for developing the technique and strength of athletes. Many martial arts forms have been studied, but a relatively new form of martial arts competition, San Shou, has not been analyzed. The purpose of this study was to determine key attributes necessary in the development of the San Shou athlete, particularly in female participants. Six elite and six novice competitors performed 30 continuous repetitions of cyclic extension and flexion of the trunk segment, knee joints, and elbows joints at two velocities, 60°/second and 180°/second, using an isokinetic dynamometer. Variables of interest were maximum torque production, normalized torque (Nm/kg), fatigue indexes (average of three maximal forces in the first three cycles/average of maximal forces in the last three cycles), and rate of torque development (Nm/s). Results indicate significant differences between groups only during trunk flexion for maximum torque, normalized torque, and rate of force development, whereas differences between movement velocities were apparent for multiple variables at each anatomic region. These analyses assist in providing further information regarding the possible key factors in developing the San Shou female athlete. Further work is required to identify additional parameters in developing the San Shou athlete

    In situ synthesis of interlinked three-dimensional graphene foam/polyaniline nanorod supercapacitor

    Get PDF
    Three-dimensional (3-D) graphene foam/PANI nanorods were fabricated by hydrothermal treatment of graphene oxide (GO) solution and sequentially in-situ synthesis of PANI nanorods on the surface of graphene hydrogel. 3-D graphene foam was used as substrate for the growth of PANI nanorods and it increases the specific surface area as well as the double layer capacitance performance of the graphene foam/PANI nanorod composite. The length of the PANI nanorod is about 340 nm. PANI nanorods exhibited a short stick shape. These PANI nanorods agglomerate together and the growth orientation is anisotropic. The highest specific capacitance of 3-D graphene/PANI nanorod composite electrodes is 352 F g−1 at the scan rate of 10 mV s−1.Institute of Textiles and Clothin

    Past hybridization between two East Asian long-tailed tits (Aegithalos bonvaloti and A. fuliginosus)

    Get PDF
    Introduction: Incomplete lineage sorting and hybridization are two major nonexclusive causes of haplotype sharing between species. Distinguishing between these two processes is notoriously difficult as they can generate similar genetic signatures. Previous studies revealed that the mitochondrial DNA (mtDNA) differentiation between two East Asian long-tailed tits (Aegithalos bonvaloti and A. fuliginosus) was extremely low, even lower than intraspecific differentiation in some other long-tailed tits. Using a combination of multilocus and coalescent analyses, we explored the causes of the anomalous lack of mtDNA differentiation between the two species.Results: The mtDNA divergence between the two species was shallow, while the nuclear DNA (nuDNA) divergence was considerably deeper. The IMa analyses based on the mtDNA dataset suggested relatively high gene flow from A. fuliginosus to A. bonvaloti, while negligible gene flow in the opposite direction. In contrast to mtDNA, the migration rates at autosomal and Z-linked nuDNA loci were negligible or much lower. The NEWHYBRIDS analysis assigned all individuals except one to pure parental species with high posterior probability. The Bayesian skyline plot showed that both species underwent population expansions during the Last Glacial Maximum (LGM), and the ecological niche modelling suggested that their ranges overlapped more during the LGM than at present.Conclusions: We suggest that historical hybridization, in combination with selective sweep and/or genetic drift might be the main causes of the extremely low mtDNA differentiation between the two species. The hybridization probably occurred mainly between A. fuliginosus females and A. bonvaloti males. The LGM distribution expansion might have facilitated hybridization, while the post-LGM distribution contraction could have facilitated some mtDNA sorting. Ongoing hybridization between the two species might be very limited, but further studies with more samples from the contact zone are needed to test this conclusion

    Electromagnetic wave absorbing properties of aligned amorphous carbon nanotube/BaFe12O19 nanorod composite

    Get PDF
    Aligned amorphous carbon nanotube (AACNT)/BaFe12O19 nanorod (BNR) composite was prepared by chemical vapor deposition and ball-milling methods. Raman and XRD tests were performed to investigate the microstructures, and the microwave absorbing properties of the as prepared composite were characterized using a vector network analyzer. The experimental results indicated that the mean length of as-prepared ACNT arrays was about 24 μm and the average length of BNRs were about 50 nm. The maximum absorbing peak of AACNTs/BNR composite is −21.5 dB at the frequency of 9.3 GHz. The frequency bandwidth of the reflectivity loss below −10 dB is about 2.5 GHz. AACNTs have both features of amorphous CNTs which have multiple-reflective path inside the tube-wall and crystalline CNTs which have high conductivity.Institute of Textiles and Clothin

    An Unstructured Phylogeographic Pattern with Extensive Gene Flow in an Endemic Bird of South China: Collared Finchbill (Spizixos semitorques)

    Get PDF
    Recent phylogeographical studies indicated that glacial oscillations played a key role on the phylogeographic pattern of extant species. As most studies have previously been carried out on heavily ice-covered regions, such as in European and North American regions, potential effects of climatic oscillations on species that are distributed on ice-free regions are less known. To address this, we investigated the phylogeographic pattern of an avian species endemic to South China, which was not glaciated during the Pleistocene glaciations. By using 2142 bp mitochondrial DNA, we identified 89 haplotypes defined by 39 polymorphic sites. A combination of high haplotype diversity (0.786–1.00) and low nucleotide diversity (0.00132–0.00252) was detected among geographic populations. Explicit genetic divergence was observed between S. s. semitorques and S. s. cinereicapillus but not detected among geographic populations of S. s. semitorques. Divergence time of the two subspecies was dated back to 87 Kyr which is congruent with the interglacial MIS 5. A weak phylogeographic structure due to strong gene flow among geographic populations was identified in this species, suggesting complex topography of South China has not formed barriers for this species

    ALS-Associated E478G Mutation in Human OPTN (Optineurin) Promotes Inflammation and Induces Neuronal Cell Death

    Get PDF
    Amyotrophic Lateral Sclerosis (ALS) is a group of neurodegenerative disorders that featured with the death of motor neurons, which leads to loss of voluntary control on muscles. The etiologies vary among different subtypes of ALS, and no effective management or medication could be provided to the patients, with the underlying mechanisms incompletely understood yet. Mutations in human Optn (Optineurin), particularly E478G, have been found in many ALS patients. In this work, we report that NF-κB activity was increased in Optn knockout (Optn−/−) MEF (mouse embryonic fibroblast) cells expressing OPTN of different ALS-associated mutants especially E478G. Inflammation was significantly activated in mice infected with lenti-virus that allowed overexpression of OPTNE478G mutation in the motor cortex, with marked increase in the secretion of pro-inflammatory cytokines as well as neuronal cell death. Our work with both cell and animal models strongly suggested that anti-inflammation treatment could represent a powerful strategy to intervene into disease progression in ALS patients who possess the distinctive mutations in OPTN gene

    Hollow-structured NiCoP nanorods as high-performance electrodes for asymmetric supercapacitors

    Get PDF
    One-dimensional hollow-structured NiCoP nanorods are synthesized via Kirkendall effect resulting from different diffusion rates of Ni and Co ions at 350 °C, using NaH2PO2 as a phosphorization agent. Various techniques were used to study the formation mechanism of hollow NiCoP nanorods which structure and crystallinity could be effectively tuned by adjusting phosphorization time. Capacitance of NiCoP reaches 273.4 μAh cm−2 at a current density of 30 mA cm−2 with a rate retention of 85.6%. Specific capacitance of an asymmetric supercapacitor cell (ASC) where NiCoP sample was used together with activated carbon reached 264.6 μAh cm−2 at 2 mA cm−2 and decreased to 213.2 μAh cm−2 with current density rising to 30 mA cm−2. The ASC possesses quite high energy- and power densities, compared to previously reported results, which demonstrates applicability of hollow NiCoP nanorods for electrochemical energy storage

    Strategies to Manage Stress and Fatigue in Athletes

    No full text
    High level athletes frequently travel for competition, participate in heavy training loads, have dense competitive schedules, and have to manage pressure to perform. All of these are sources of stress and if not strategically managed could lead to fatigue, decreased performance, and increased risk for injury. The purpose of this review is to provide the reader scientifically based strategies to manage stress and promote performance. Specific attention will focus on the influence of travel, sleep, and training load

    Gravity Anomaly and Satellite Altimetry in the China Seas: Applications to Geodynamics

    No full text
    Satellite altimetry has become an operational remote sensing technique with important applications to geodynamics. In the present paper, ocean floor topography and tectonic detection in the deep earth are investigated using gravity anomalies from global gravity models and satellite altimetry corrected for waveform distortions. We compute the spherical harmonic degree components of the gravity anomaly from gravity models (up to degree 360), and use inverse the Vening Meinesz formula in the remove-restore procedure to obtain the residual gravity anomaly components higher than degree 360. This paper is intended to give a geodynamical analysis on the gravity anomaly components from the crust, upper mantle, and lower mantle. On this base, the geodynamics background and mechanism in an area of the China Seas (25°N ~ 42°N, 118°E ~ 130°E) are studied. The evidence shows gravity anomaly of different degree in the study area is mainly due to mass distribution of different depth, and the dynamical imbalance from the geopotential imbalance should be responsible for global dynamics activities, which change the lithosphere structure through mantle circulation

    Local farmers' perceptions of ecosystem services and disservices provided by the Black-necked Crane (Grus nigricollis) and their conservation implications

    No full text
    Incorporating local farmers' perceptions into conservation management has great significance because they have become the key stakeholders in wildlife conservation, especially that of waterbirds. The Black-necked Crane (Grus nigricollis) interacts closely with local farmers throughout its distribution, resulting in human–bird conflict. The evaluation of ecosystem services/disservices among local populations should help to address this relationship. We examined local farmers' perceptions of agreement with the ecosystem services and disservices provided by the Black-necked Crane in one of its large wintering sites by conducting semi-structured interviews with farmers around Caohai Wetland in Guizhou Province, China. The influences of socio-demographic variables, ecological knowledge, and attitude on farmers' agreement with ecosystem services and disservices were explored by generalized linear mixed models. Most of the farmers perceived a few benefits from the Black-necked Crane, whereas approximately one-third of them regarded the species as harmful. The most mentioned service was aesthetic value, followed by leisure and ecotourism, and therapeutic value, while crop consumption was the most commonly mentioned disservice. Their levels of agreement with services were associated with attitude and age, while those with disservices were determined by education attainment and household size. Local government and conservation organizations could use social media platforms, such as TikTok and WeChat, to convey information on the benefits or ecosystem services provided by the black-necked crane, and ecological compensation could be implemented to alleviate farmer–bird conflict. This study demonstrated the significance of the inclusion of local stakeholders and ecosystem service evaluation in conservation management. This framework can be applied to other protected species or ecosystems facing similar situations
    corecore