This study investigated the 30-days altitude training (2500 m, LHTH-live and training high) on hematological responses and aerobic-anaerobic performances parameters of high-level Paralympic athletes. ...Aerobic capacity was assessed by 3000 m run, and anaerobic variables (velocity, force and mechanical power) by a maximal 30-s semi-tethered running test (AO30). These assessments were carried out at low altitude before (PRE) and after LHTH (5-6 and 15-16 days, POST1 and POST2, respectively). During LHTH, hematological analyzes were performed on days 1, 12, 20 and 30. After LHTH, aerobic performance decreased 1.7% in POST1, but showed an amazing increase in POST2 (15.4 s reduction in the 3000 m test, 2.8%). Regarding anaerobic parameters, athletes showed a reduction in velocity, force and power in POST1, but velocity and power returned to their initial conditions in POST2. In addition, all participants had higher hemoglobin (Hb) values at the end of LHTH (30 days), but at POST2 these results were close to those of PRE. The centrality metrics obtained by complex networks (pondered degree, pagerank and betweenness) in the PRE and POST2 scenarios highlighted hemoglobin, hematocrit (Hct) and minimum force, velocity and power, suggesting these variables on the way to increasing endurance performance. The Jaccard's distance metrics showed dissimilarity between the PRE and POST2 graphs, and Hb and Hct as more prominent nodes for all centrality metrics. These results indicate that adaptive process from LHTH was highlighted by the complex networks, which can help understanding the better aerobic performance at low altitude after 16 days in Paralympic athletes.
This study investigates particle size reduction and interparticle agglomeration in clear and milky quartz ground in a planetary ball mill for up to 32 h. Particle size distribution and specific ...surface area were assessed using laser scattering and nitrogen physisorption methods. The heterogeneity in size distribution was calculated using the Rosin-Rammler equation. The onset of agglomeration occurred earlier for clear quartz (4 h) than for milky quartz (16 h). The resistance of the agglomerates formed with clear quartz debris against alkaline dissolution was stronger. These differences were discussed considering the population of ultrafine particles, the line broadening of X-ray diffraction patterns and the paramagnetic centers measured by EPR spectroscopy. The increase in peroxy center concentration occurred simultaneously with the onset of agglomeration. Since no difference was found in hardness and fracture toughness, the lower grinding rates of milky quartz was explained by the higher fracture strength of its polycrystalline microtexture.
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•Use of dry planetary ball milling to describe size reduction and agglomeration in quartz.•Particle size distribution and grinding rate depend on quartz petrographic properties.•Clear quartz fragments agglomerate earlier than polycrystalline milky quartz debris.•Assessment of structural and surface changes by X-ray diffraction and EPR spectroscopy.•Agglomeration onset and rise-up of peroxy center concentration happens simultaneously.
The effect of ultrafine dry grinding for up to 1920 min in a planetary ball mill at 300 rpm on size distribution, particle agglomeration and bulk structural changes in a dolomite-rich (CaMg(CO3)2) ...rock was studied. The size and shape of the ground particles were characterized by laser scattering and scanning electron microscopy (SEM) respectively. The uniformity index of the size distribution evaluated using the Rosin-Rammler equation showed that the apparent grinding limit was reached after 480 min. Differential- and thermo-gravimetric (DTA-TG) analyses showed that the decomposition temperature of magnesite (MgCO3) was affected to a far greater extent by the input energy of grinding than that of calcite (CaCO3). The activation energy of the total decomposition decreased for the aliquots ground above 480 min. This behavior was explained by the storage of extensive lattice distortions in dolomite crystal structure evaluated by X ray line profile analysis of major diffracting peaks. The infrared (IR) bands related to the bending (877 cm−1) and stretching (1418 cm−1) vibrations of the anionic CO32– groups increased with the particle size decreasing as well as being sensitive to particle coarsening caused by agglomeration. Coupled to morphological and Rosin-Rammler size distribution analyses, IR data confirmed extensive agglomeration above 480 min. The transformation between calcite and aragonite polymorphs was also noticed in those aliquots ground for periods ≥480 min. The bulk structural changes documented here were useful to show that the inversion from the breakage to the agglomeration regime observed in dolostone powder system is directly associated with the change in the energy relaxation mechanism inside the dolomite grains.
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•A dolomite-rich rock was ground for up to 32 h in a planetary ball mill•Particle size distribution and crystal regularity were investigated by different methods•Grinding limit, agglomeration and bulk structural changes occurred after 480 min•Extensive lattice distortions in dolomite explained changes in thermal decomposition•Brittle fracture – plastic flow transition was identified in ultrafine grinding of dolostone
The purpose of the current study was to investigate the relationship between alternative anaerobic capacity method (MAODALT) and a 30-s all-out tethered running test. Fourteen male recreational ...endurance runners underwent a graded exercise test, a supramaximal exhaustive effort and a 30-s all-out test on different days, interspaced by 48h. After verification of data normality (Shapiro-Wilk test), the Pearson's correlation test was used to verify the association between the anaerobic estimates from the MAODALT and the 30-s all-out tethered running outputs. Absolute MAODALT was correlated with mean power (r = 0.58; P = 0.03), total work (r = 0.57; P = 0.03), and mean force (r = 0.79; P = 0.001). In addition, energy from the glycolytic pathway (ELa-) was correlated with mean power (r = 0.58; P = 0.03). Significant correlations were also found at each 5s interval between absolute MAODALT and force values (r between 0.75 and 0.84), and between force values and ELa- (r between 0.73 to 0.80). In conclusion, the associations between absolute MAODALT and the mechanical outputs from the 30-s all-out tethered running test evidenced the importance of the anaerobic capacity for maintaining force during the course of time in short efforts.
This study's aims to verify the energy expenditure, metabolic distress and usefulness to evaluate the anaerobic constructs for different all-out durations in running efforts. Twelve active male ...underwent four testing sessions, one for familiarization and three performing one all-out (AO) tethered running sprint lasting 30s, 20s or 10s. Oxygen consumption, excess post exercise oxygen consumption, and lactate production were retained to analyse metabolic function, together with mechanical power and work as performance parameters. Paired results were compared via one-way ANOVA for repeated measures (Tukey-HSD post-hoc), effect sizes and ICC for absolute agreement. Statistical significance was accepted at p ≤ 0.05. Despite total and energy expenditure from oxidative pathway being significantly higher for longer durations (p < 0.001; ES > 0.7), glycolytic energy expenditure presented an agreement between AO30s and AO20s (ICC-A = 0.63*), while the paired comparisons to AO10s have presented significant differences (p < 0.01; ES > 1.0). Phosphagen energy expenditure were similar between all-out durations (p = 0.12; ICC-A = 0.62*; ES < 0.5). Maximum mechanical power was higher in AO10s than in AO30s (p = 0.03; ES = 0.6), not being different between AO10s and AO20s (p = 0.67; ICC-A = 0.88*; ES = 0.2) and between AO20s and AO30s (p = 0.18; ICC-A = 0.56*; ES = 0.4). In addition, agreement between work in the first ten seconds was confirmed via ICC only between AO10s and AO20s (p = 0.50; ICC-A = 0.86*; ES = 0.3), but not for the other paired comparisons (p < 0.1; ICC < 0.45; ES > 0.5). AO20s is a better alternative to estimate anaerobic power and capacity in one single test, with similar oxidative demand than AO30s.
This study was divided into two complementary parts. In Part 1, we proposed a novel paddle strokes analysis based on the force signal from a 30-s all-out tethered test; and compared these results ...with video recordings. In Part 2, we investigated the relationship between force data from the same test with paddle stroke results from both methods. Eleven male elite slalom kayakers (Brazilian national team) were evaluated. The tethered test was conducted for force parameters analysis (peak-force, mean-force, impulse). Video recording analysis was conducted, and the performed strokes (V.NumberPaddle) was counted and frequency (V.FrequencyPaddle) calculated by the V.NumberPaddle divided by 30 (i.e. total time of test). The new method consisted of performed strokes and frequency achievement from a load cell force signal analysis (S.NumberPaddle and S.FrequencyPaddle, respectively). Paired test-t did not show difference between methods results, but significant correlations were only obtained for the number of paddle strokes. Force parameters were only correlated with S.NumberPaddle and S.FrequencyPaddle. Overall, considering the theoretical and practical application, we propose that the new method should be used as an alternative to the video recording.
Introduction
Paediatric HIV follow‐up is challenging, and treatment indicators are markedly far from Joint United Nations Programme on HIV/AIDS (UNAIDS) goals. In this study, we describe the 2019 ...Brazilian HIV cascade according to age categories and sociodemographic variables and address temporal trends between 2009 and 2019.
Methods
We obtained data from the Brazilian Ministry of Health monitoring database. Cascade outcomes included retention in care, antiretroviral use, and viral suppression. We assessed the effect of age on timely initiation of antiretroviral treatment (ART; initiation with CD4+ T‐cell count ≥350 cells/mm3 or a first ART dispensation ≤30 days after the first CD4+ T‐cell measurement) and detectable HIV viral load (>50 copies/mL) in univariable and multivariable analysis adjusted for sex, race, and social vulnerability index (SVI). Temporal trends in timely ART initiation and viral suppression were evaluated graphically.
Results
Among 771 774 people living with HIV, those in the youngest age categories had poorer indicators in the care cascade. Those in younger age groups, those with higher SVI, and those declaring Black and native Brazilian race/ethnicity had higher odds of having detectable viral load and delayed ART initiation. Although children living with HIV tend to start ART with higher CD4+ T‐cell counts, time–series analysis suggests that improvements in treatment indicators seen in the adult population are not observed in the paediatric population.
Conclusion
Our results highlight the challenges faced by children and adolescents living with HIV in achieving UNAIDS goals. Lower access to ART among children is a central barrier to improved paediatric care.
The purpose of the study was to investigate if the 3-min all-out test (3MT) is valid for obtaining critical power intensity (CP) and the amount of work that can be performed above CP (W') on ...non-motorized treadmills in tethered running. Eight physically active individuals (24 ± 3 years; 78.3 ± 8.7 kg; 179 ± 5 cm; 9.0 ± 2.5% body fat) performed four different efforts at constant intensity to exhaustion in order to determine CP and W'. The mechanical power values obtained were subsequently plotted with their corresponding time to exhaustion (limit time) for application of three mathematical models: power hyperbolic versus time limit (Hyp), linear power versus 1/time (P vs 1/t) and linear work versus time limit (Ԏ vs t). The 3MT test was carried out on the last day to determine end power (EP) and anaerobic capacity (WEP) using this methodology. EP value of 181.7 ± 52 was similar (p = 0.486) to 178.2 ± 61 (CP Hyp), 191.4 ± 55 (Ԏ vs t) and 188.3 ± 55 (P vs 1/t). WEP value of 17.9 ± 4.8 was not similar (p = 0.000) to 50.2 ± 15.3 (CP Hyp), 44.8 ± 8.7 (Ԏ vs t) and 45.5 ± 8.4 (P vs 1/t). Positive results (r = 0.78-0.98 and ICC = 0.88-0.99) of Pearson correlation and intraclass correlation (ICC-absolute agreement) were found for aerobic applications of conventional CP and 3MT. For anaerobic data, only the three models of conventional CP were correlated (r = 0.76-0.93); however, W' from the three models was not correlated with WEP (r = 0.37-0.52). The results of this study suggest that 3MT in tethered running on non-motorized treadmills is a valid test for estimating CP aerobic parameters in a single day of application but not anaerobic parameters of W'.
Hermit crabs finding themselves in a trapped shell face a critical decision that will require an assessment of the benefits of abandonment against the increased risks of predation and desiccation. ...This study investigates factors that influence the rate of shell abandoning by common intertidal hermit crabs. We firstly established that the mud inhabitant, Pagurus criniticornis, exhibits a greater tendency to abandon shells when compared to its neighbors Pagurus brevidactylus and Clibanarius antillensis. We subsequently conducted a series of experiments on this species to assess the relative influence of (1) gastropod shell type, (2) shell adequacy, (3) shell condition, (4) olfactory attractants, (5) previous experience, and (6) shell acclimatization. P. criniticornis abandoned very small shells faster than optimal (well-fitting) specimens and damaged shells faster and more completely than intact specimens. Crabs exposed to olfactory cues (Cerithium atratum) were 15% more likely to abandon their shells than unexposed individuals. Similarly, individuals that had undergone previous abandonment experience and those given longer acclimatization periods (30 vs. 2 days) showed rates of abandonment that were 18 and 28% greater than contrasting treatments. The results can be used to aid our understanding of motivational behavior in invertebrates and other animals that inhabit temporary or ephemeral shelters.
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