189 research outputs found

    Post‐activation potentiation: is there an optimal training volume and intensity to Induce improvements in vertical jump ability in highly‐trained subjects?

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    The aim of this study was to compare the acute effects of performing half squats (HSs) with different loading intensities (1, 3, and 5 repetitions maximum [RM], and 60% 1RM) and a different number of sets (1, 2, and 3) on the countermovement jump (CMJ) performance of 18 highly‐trained male subjects. Participants were submitted to four experimental conditions (1RM, 3RM, 5RM, and 60% 1RM) in randomized order. The CMJ was assessed before and after each set. Differences in CMJ performance between the distinct experimental conditions and individual responses in CMJ performance induced by the different protocols were analyzed via the magnitude‐based inference method. Overall, significant improvements were detected in individual CMJ heights after each activation protocol. It can be concluded that the use of 1 to 3 sets of HSs performed at moderate‐to‐high loads may be an effective strategy to improve jump performance in highly‐trained subjects. Nonetheless, despite the high efficiency of the protocols tested here, coaches and researchers are strongly encouraged to perform individualized assessments within the proposed range of loads and sets, to find optimal and tailored post‐activation potentiation protocols

    Post-activation potentiation: is there an optimal training volume and intensity to induce improvements in vertical jump ability in highly-trained subjects?

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    The aim of this study was to compare the acute effects of performing half squats (HSs) with different loading intensities (1, 3, and 5 repetitions maximum [RM], and 60% 1RM) and a different number of sets (1, 2, and 3) on the countermovement jump (CMJ) performance of 18 highly-trained male subjects. Participants were submitted to four experimental conditions (1RM, 3RM, 5RM, and 60% 1RM) in randomized order. The CMJ was assessed before and after each set. Differences in CMJ performance between the distinct experimental conditions and individual responses in CMJ performance induced by the different protocols were analyzed via the magnitude-based inference method. Overall, significant improvements were detected in individual CMJ heights after each activation protocol. It can be concluded that the use of 1 to 3 sets of HSs performed at moderate-to-high loads may be an effective strategy to improve jump performance in highly-trained subjects. Nevertheless, despite the high efficiency of the protocols tested here, coaches and researchers are strongly encouraged to perform individualized assessments within the proposed range of loads and sets, to find optimal and tailored post-activation potentiation protocols

    Primary debulking surgery versus primary neoadjuvant chemotherapy for high grade advanced stage ovarian cancer: Comparison of survivals

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    The aim of the study was to analyze the overall survival (OS) and progression free survival (PFS) of patients with high grade and advanced stage epithelial ovarian cancer (EOC) with at least 60 months of follow-up treated in a single gynecologic oncology institute. We compared primary debulking surgery (PDS) versus neoadjuvant chemotherapy plus interval debulking surgery (NACT + IDS) stratifying data based on residual disease with the intent to identify the rationale for therapeutic option decision and the role of laparoscopic evaluation of resectability for that intention. This is observational retrospective study on consecutive patients with diagnosis of high grade and International Federation of Gynecology and Obstetrics (FIGO) stage III/IV EOC referred to our center between January 2008 and May 2012. We selected only patients with a follow-up of at least 60 months. Primary endpoint was to compare PDS versus NACT + IDS in term of progression free survival (PFS) and overall survival (OS). Secondary endpoints were PFS and OS stratifying data according to residual disease after surgery in patients receiving PDS versus NACT + IDS. Finally, through Cox hazards models, we tested the prognostic value of different variables (patient age at diagnosis, residual disease after debulking, American Society of Anesthesiologists (ASA) stage, number of adjuvant-chemotherapy cycles) for predicting OS. A total number of 157 patients were included in data analysis. Comparing PDS arm (108 patients) and NACT + IDS arm (49 patients) we found no significant differences in term of OS (41.3 versus 34.5 months, respectively) and PFS (17.3 versus 18.3 months, respectively). According to residual disease we found no significant differences in term of OS between NACT + IDS patients with residual disease = 0 and PDS patients with residual disease = 0 or residual disease = 1, as well as no significant differences in PFS were found comparing NACT + IDS patients with residual disease = 0 and PDS patients with residual disease = 0; contrarily, median PFS resulted significantly lower in PDS patients receiving optimal debulking (residual disease = 1) in comparison to NACT + IDS patients receiving complete debulking (residual disease = 0). PDS arm was affected by a significant higher rate of severe post-operative complications (grade 3 and 4). Diagnostic laparoscopy before surgery was significantly associated with complete debulking. We confirm previous findings concerning the non-superiority of NACT + IDS compared to PDS for the treatment of EOC, even if NACT + IDS treatment was associated with significant lower rate of post-operative complications. On the other hand, selecting patients for NACT + IDS, based on laparoscopic evaluation of resectabilty prolongs the PFS and does not worse the OS compared to the patients not completely debulked with PDS

    Muon content of ultra-high-energy air showers: Yakutsk data versus simulations

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    We analyse a sample of 33 extensive air showers (EAS) with estimated primary energies above 2\cdot 10^{19} eV and high-quality muon data recorded by the Yakutsk EAS array. We compare, event-by-event, the observed muon density to that expected from CORSIKA simulations for primary protons and iron, using SIBYLL and EPOS hadronic interaction models. The study suggests the presence of two distinct hadronic components, ``light'' and ``heavy''. Simulations with EPOS are in a good agreement with the expected composition in which the light component corresponds to protons and the heavy component to iron-like nuclei. With SYBILL, simulated muon densities for iron primaries are a factor of \sim 1.5 less than those observed for the heavy component, for the same electromagnetic signal. Assuming two-component proton-iron composition and the EPOS model, the fraction of protons with energies E>10^{19} eV is 0.52^{+0.19}_{-0.20} at 95% confidence level.Comment: 8 pages, 3 figures; v2: replaced with journal versio

    Time-Frequency Analysis of Chemosensory Event-Related Potentials to Characterize the Cortical Representation of Odors in Humans

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    BACKGROUND: The recording of olfactory and trigeminal chemosensory event-related potentials (ERPs) has been proposed as an objective and non-invasive technique to study the cortical processing of odors in humans. Until now, the responses have been characterized mainly using across-trial averaging in the time domain. Unfortunately, chemosensory ERPs, in particular, olfactory ERPs, exhibit a relatively low signal-to-noise ratio. Hence, although the technique is increasingly used in basic research as well as in clinical practice to evaluate people suffering from olfactory disorders, its current clinical relevance remains very limited. Here, we used a time-frequency analysis based on the wavelet transform to reveal EEG responses that are not strictly phase-locked to onset of the chemosensory stimulus. We hypothesized that this approach would significantly enhance the signal-to-noise ratio of the EEG responses to chemosensory stimulation because, as compared to conventional time-domain averaging, (1) it is less sensitive to temporal jitter and (2) it can reveal non phase-locked EEG responses such as event-related synchronization and desynchronization. METHODOLOGY/PRINCIPAL FINDINGS: EEG responses to selective trigeminal and olfactory stimulation were recorded in 11 normosmic subjects. A Morlet wavelet was used to characterize the elicited responses in the time-frequency domain. We found that this approach markedly improved the signal-to-noise ratio of the obtained EEG responses, in particular, following olfactory stimulation. Furthermore, the approach allowed characterizing non phase-locked components that could not be identified using conventional time-domain averaging. CONCLUSION/SIGNIFICANCE: By providing a more robust and complete view of how odors are represented in the human brain, our approach could constitute the basis for a robust tool to study olfaction, both for basic research and clinicians

    The Human Operculo-Insular Cortex Is Pain-Preferentially but Not Pain-Exclusively Activated by Trigeminal and Olfactory Stimuli

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    Increasing evidence about the central nervous representation of pain in the brain suggests that the operculo-insular cortex is a crucial part of the pain matrix. The pain-specificity of a brain region may be tested by administering nociceptive stimuli while controlling for unspecific activations by administering non-nociceptive stimuli. We applied this paradigm to nasal chemosensation, delivering trigeminal or olfactory stimuli, to verify the pain-specificity of the operculo-insular cortex. In detail, brain activations due to intranasal stimulation induced by non-nociceptive olfactory stimuli of hydrogen sulfide (5 ppm) or vanillin (0.8 ppm) were used to mask brain activations due to somatosensory, clearly nociceptive trigeminal stimulations with gaseous carbon dioxide (75% v/v). Functional magnetic resonance (fMRI) images were recorded from 12 healthy volunteers in a 3T head scanner during stimulus administration using an event-related design. We found that significantly more activations following nociceptive than non-nociceptive stimuli were localized bilaterally in two restricted clusters in the brain containing the primary and secondary somatosensory areas and the insular cortices consistent with the operculo-insular cortex. However, these activations completely disappeared when eliminating activations associated with the administration of olfactory stimuli, which were small but measurable. While the present experiments verify that the operculo-insular cortex plays a role in the processing of nociceptive input, they also show that it is not a pain-exclusive brain region and allow, in the experimental context, for the interpretation that the operculo-insular cortex splay a major role in the detection of and responding to salient events, whether or not these events are nociceptive or painful

    Atmospheric effects on extensive air showers observed with the Surface Detector of the Pierre Auger Observatory

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    Atmospheric parameters, such as pressure (P), temperature (T) and density, affect the development of extensive air showers initiated by energetic cosmic rays. We have studied the impact of atmospheric variations on extensive air showers by means of the surface detector of the Pierre Auger Observatory. The rate of events shows a ~10% seasonal modulation and ~2% diurnal one. We find that the observed behaviour is explained by a model including the effects associated with the variations of pressure and density. The former affects the longitudinal development of air showers while the latter influences the Moliere radius and hence the lateral distribution of the shower particles. The model is validated with full simulations of extensive air showers using atmospheric profiles measured at the site of the Pierre Auger Observatory.Comment: 24 pages, 9 figures, accepted for publication in Astroparticle Physic

    Assessing Implicit Odor Localization in Humans Using a Cross-Modal Spatial Cueing Paradigm

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    Navigation based on chemosensory information is one of the most important skills in the animal kingdom. Studies on odor localization suggest that humans have lost this ability. However, the experimental approaches used so far were limited to explicit judgements, which might ignore a residual ability for directional smelling on an implicit level without conscious appraisal.A novel cueing paradigm was developed in order to determine whether an implicit ability for directional smelling exists. Participants performed a visual two-alternative forced choice task in which the target was preceded either by a side-congruent or a side-incongruent olfactory spatial cue. An explicit odor localization task was implemented in a second experiment.No effect of cue congruency on mean reaction times could be found. However, a time by condition interaction emerged, with significantly slower responses to congruently compared to incongruently cued targets at the beginning of the experiment. This cueing effect gradually disappeared throughout the course of the experiment. In addition, participants performed at chance level in the explicit odor localization task, thus confirming the results of previous research.The implicit cueing task suggests the existence of spatial information processing in the olfactory system. Response slowing after a side-congruent olfactory cue is interpreted as a cross-modal attentional interference effect. In addition, habituation might have led to a gradual disappearance of the cueing effect. It is concluded that under immobile conditions with passive monorhinal stimulation, humans are unable to explicitly determine the location of a pure odorant. Implicitly, however, odor localization seems to exert an influence on human behaviour. To our knowledge, these data are the first to show implicit effects of odor localization on overt human behaviour and thus support the hypothesis of residual directional smelling in humans

    An integrated ultrasound curriculum (iUSC) for medical students: 4-year experience

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    A review of the development and implementation of a 4-year medical student integrated ultrasound curriculum is presented. Multiple teaching and assessment modalities are discussed as well as results from testing and student surveys. Lessons learned while establishing the curriculum are summarized. It is concluded that ultrasound is a well received, valuable teaching tool across all 4 years of medical school, and students learn ultrasound well, and they feel their ultrasound experience enhances their medical education
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