SURFACE MARKERS VERSUS CLUSTERS FOR DETERMINING LOWER LIMB JOINT KINEMATICS IN SPRINT RUNNING

The purpose of this study was to compare lower limb joint angle time histories using surface markers and segmental clusters. An athlete completed three single leg standing trials whilst moving the joints of the free leg from maximum flexion to maximum extension followed by seven maximal sprint runs. Trials were tracked by a three-dimensional CODA system. For standing trials, mean timing differences were greatest in maximum extension at the ankle and hip (0.01 s). Angle differences ranged from 2° (knee flexion) to 11° (ankle extension). Timing differences in sprinting were greatest in extension (hip 0.03 s) with joint angle differences in maximum flexion and extension 7 & 9° (ankle), 3 & 6° (knee) and 23 & 4° (hip) respectively. When comparing results from surface markers and clusters, a good level of agreement was found in the continuous knee flexion-extension profile, and the discrete timings for all joints

Biomechanical evolution of the Tkachev on uneven bars in female gymnastics

The development of joint kinematics and kinetics is fundamental to the successful performance of complex flight skills in gymnastics bar routines. Biomechanical understanding of these skills can provide coaches and scientists with key information to make training safe and effective. The Tkachev is a complex and popular gymnastics skill with many different variations. Recently, a new version has been performed, which has become popular with elite female performers. This study examined the key biomechanical characteristics of this skill and contrasted these to the earlier versions reported. Elite female gymnasts (n = 5) were recorded and manually digitised using twin video cameras (50 Hz) at the 2007 World Gymnastics Championships. Three-dimensional (3D) DLT was used to reconstruct the real world coordinates. Individualised inertia characteristics were calculated and used to determine mass centre kinematics. Inverse dynamics analysis was used to calculate joint kinetics at the hips and shoulders from the known values at the toes. The results of this study showed an increased flight time and rotational capacity during the aerial phase for the toe-on Tkachev, as well as a more simple movement pattern and joint kinetic demand with single power impulses at the hips and shoulders compared with previous versions. The key finding of this study was that the toe-on version appeared to be less physically demanding than that the inward and outward techniques, and provide the opportunity to perform more complex aerial phase body positions. These results can help coaches to physically prepare their gymnasts and biomechanists in terms of understanding the demands of these skills

Simulation and Economic Modelling of a Floating Solar Photovoltaic (FSPV) System using PVSyst

This paper examines the economic feasibility of implementing a Floating Solar Photovoltaic (FSPV) system in a Philippine Lake using the PVsyst simulation tool. The study involved a detailed simulation of the FSPV system's performance, considering various environmental and technical parameters. Key aspects such as system configuration, energy yield, and financial metrics including payback period and net present value were analyzed. Results indicate that the FSPV system could significantly contribute to local energy needs while proving to be a financially viable investment due to substantial reductions in CO2 emissions and lower energy costs compared to traditional power sources. According to assessments and simulations performed using PVSyst software, the FSPV system would possess a capacity of 10 kWp, with an expected available energy output of 13,599 kWh per year and an expected energy consumption of 12,940 kWh per year. The economic modeling of the FSPV system revealed a relatively short payback period of 4.8 years, with a net present value of Php 741,732.00 and a substantial return on investment of 227.5%. The Levelized Cost of Energy (LCOE) was estimated at Php 6.18 per kWh. The study underscores the potential of FSPV systems to meet the renewable energy needs of isolated communities by leveraging local water bodies for solar installations

Current Trends, Advancements, and Challenges in Floating Solar Photovoltaic (FSPV) Systems for Off-Grid Applications: A Review

Increasing energy demands and the pursuit of sustainable and clean energy sources have intensified interest in Floating Solar Photovoltaic (FSPV) systems, particularly for off-grid applications. FSPV technology presents a strategic alternative for countries with limited land but ample water bodies, contributing to energy diversification and conservation of arable land. This paper provides a comprehensive technological trends, advancements, and challenges in the deployment of FSPV systems, drawing from an array of highly regarded publications and extensive patent searches via the Derwent Innovation database and various publications. While large-scale FSPV deployments have been successfully integrated with existing hydroelectric power plants and grid systems, the application of FSPV technology for local community use remains underexplored. The paper identifies the lack of comprehensive literature on stand-alone FSPV systems that include battery charging capabilities and integrated monitoring and control systems to mitigate environmental risks. Moreover, the paper discusses the economic, regulatory, technical, cultural, and environmental barriers to FSPV deployment. It suggests that continuous research and development, backed by supportive policy frameworks, are crucial for overcoming these challenges. The aim is to pave the way for resilient, community-centric FSPV installations that can withstand extreme weather and cater to localized energy needs

Missing safer sex strategies in HIV Prevention: A call for further research

Despite the efforts of educators, public health officials, and HIV/AIDS prevention experts, condom promotion has failed to stop the HIV epidemic in most of sub- Saharan Africa and most researchers and policy makers have focused on risk reductions for interventions for penetrative sex. We consider another HIV prevention option: female-to-male oral sex (fellatio). Extensive medical evidence indicates that fellatio is roughly as protective against HIV transmission as vaginal sex with a condom, and much safer than unprotected sex, but it is rarely emphasized in HIV prevention curricula. Moreover, available data on the practice of oral sex in Africa suggests that the practice is very rare compared to the practice in the United States. This paper reviews some of the existing evidence on the efficacy and prevalence of oral sex, discusses the potential of this safer sex strategy for mitigating the spread of HIV in Africa, and stresses the need for further research

Striatal dopamine D2 receptor binding of risperidone in schizophrenic patients as assessed by 123I-iodobenzamide SPECT: a comparative study with olanzapine

The aim of this investigation was to compare the degree of striatal dopamine-(D2) receptor blockade by two atypical antipsychotic drugs, risperidone and olanzapine. The percentage of D2 receptor occupancy during treatment was calculated by comparing the results of 123I-iodobenzamide SPECT with those from healthy control subjects. Twenty inpatients suffering from schizophrenia or schizoaffective psychosis according to DSM IV/ICD-10 criteria were treated with clinically recommended doses of risperidone and compared with 13 inpatients treated with up to 20 mg olanzapine. Neuroleptic dose and D2 receptor blockade correlated strongly for both risperidone (Pearson r = –0.86, p = 0.0001) and olanzapine (Pearson r = –0.77, p = 0.002). There was no significant difference between the D2 receptor occupancy of the two substances when given in the clinically recommended dose range (unpaired t-test, t= –0.112, p=0.911)

Fluvoxamine for aripiprazole-associated akathisia in patients with schizophrenia: a potential role of sigma-1 receptors

<p>Abstract</p> <p>Background</p> <p>Second-generation antipsychotic drugs have been reported to cause fewer incidences of extrapyramidal side effects (EPSs) than typical antipsychotic drugs, but adverse events such as akathisia have been observed even with atypical antipsychotic drugs. Although understanding of the pathophysiology of akathisia remains limited, it seems that a complex interplay of several neurotransmitter systems might play a role in its pathophysiology. The endoplasmic reticulum protein sigma-1 receptors are shown to regulate a number of neurotransmitter systems in the brain.</p> <p>Methods</p> <p>We report on two cases in which monotherapy of the selective serotonin reuptake inhibitor and sigma-1 receptor agonist fluvoxamine was effective in ameliorating the akathisia of patients with schizophrenia treated with the antipsychotic drug aripiprazole.</p> <p>Results</p> <p>The global score on the Barnes Akathisia Scale in the two patients with schizophrenia treated with aripiprazole decreased after fluvoxamine monotherapy.</p> <p>Conclusion</p> <p>Doctors may wish to consider fluvoxamine as an alternative approach in treating akathisia associated with antipsychotic drugs such as aripiprazole.</p

Ab initio simulations of the kinetic properties of the hydrogen monomer on graphene

The understanding of the kinetic properties of hydrogen (isotopes) adatoms on graphene is important in many fields. The kinetic properties of hydrogen-isotope (H, D and T) monomers were simulated using a composite method consisting of density functional theory, density functional perturbation theory and harmonic transition state theory. The kinetic changes of the magnetic property and the aromatic $\pi$ bond of the hydrogenated graphene during the desorption and diffusion of the hydrogen monomer was discussed. The vibrational zero-point energy corrections in the activation energies were found to be significant, ranging from 0.072 to 0.205 eV. The results obtained from quantum-mechanically modified harmonic transition state theory were compared with the ones obtained from classical-limit harmonic transition state theory over a wide temperature range. The phonon spectra of hydrogenated graphene were used to closely explain the (reversed) isotope effects in the prefactor, activation energy and jump frequency of the hydrogen monomer. The kinetic properties of the hydrogen-isotope monomers were simulated under conditions of annealing for 10 minutes and of heating at a constant rate (1.0 K/s). The isotope effect was observed; that is, a hydrogen monomer of lower mass is desorbed and diffuses more easily (with lower activation energies). The results presented herein are very similar to other reported experimental observations. This study of the kinetic properties of the hydrogen monomer and many other involved implicit mechanisms provides a better understanding of the interaction between hydrogen and graphene.Comment: Accepted by J. Phys. Chem.

Serotonergic Polymorphisms and Psychotic Disorders in Populations From North Spain

There is strong biological evidence relating alterations in the serotonergic system with mental disorders. These alterations may be originated at the DNA level by sequence mutations that alter the functioning of serotonin receptors and transporter. To test this hypothesis we investigated three genetic variants of the 5-HT2A receptor (-1438G/A, 102T/C and His452Tyr) and two variants of the serotonin transporter (a VNTR in the second intron and a 44 bp insertion/delition in the promoter region of the gene) in a clinical sample recruited in a human isolate and in surrounding areas in Northern Spain (N = 257) and in ethnically matched controls (N = 334). No clear association was found between 5-HT2A variants and psychosis. However, marginal associations were observed between the 5-HTT LPR and VNTR variants and psychosis (P < or = 0.05) indicating a minor contribution to psychosis of genetic alterations in this gene