Effect of permissive dehydration on induction and decay of heat acclimation, and temperate exercise performance

Purpose: It has been suggested that dehydration is an independent stimulus for heat 32 acclimation (HA), possibly through influencing fluid-regulation mechanisms and increasing 33 plasma volume (PV) expansion. There is also some evidence that HA may be ergogenic in 34 temperate conditions and that this may be linked to PV expansion. We investigated: i) the 35 influence of dehydration on the time-course of acquisition and decay of HA; ii) whether 36 dehydration augmented any ergogenic benefits in temperate conditions, particularly those related to PV expansion. Methods: Eight males (VO2max: 56.9(7.2) mL·kg-1 ·min-1 37 ) undertook 38 two HA programmes (balanced cross-over design), once drinking to maintain euhydration 39 (HAEu) and once with restricted fluid-intake (HADe). Days 1, 6, 11 and 18 were 60 min exercise- 40 heat stress tests (HST [40°C; 50%RH]), days 2-5 and 7-10 were 90 min, isothermal-strain 41 (Tre~38.5°C), exercise-heat sessions. Performance parameters (VO2max, lactate threshold, 42 efficiency, peak power output [PPO]) were determined pre and post HA by graded exercise test 43 (22°C; 55 %RH). Results: During isothermal-strain sessions hypohydration was achieved in 44 HADe and euhydration maintained in HAEu (average body mass loss -2.71(0.82)% vs. - 45 0.56(0.73)%, P<0.001), but aldosterone concentration, power output and cardiovascular strain 46 were unaffected by dehydration. HA was evident on day 6 (reduced end-exercise Tre [- 0.30°C(0.27)] and exercise heart rate [-12(15) beats.min-1 47 ], increased PV [+7.2(6.4)%] and sweat-loss [+0.25(0.22) L.hr-1 48 ], P<0.05) with some further adaptations on day 11 (further reduced end-exercise Tre [-0.25(0.19)°C] and exercise heart rate [-3(9) beats.min-1 49 ], P<0.05). 50 These adaptations were not notably affected by dehydration and were generally maintained 7- 51 days post HA. Performance parameters were unchanged, apart from increased PPO (+16(20) 52 W, irrespective of condition). Conclusions: When thermal-strain is matched, permissive 53 dehydration which induces a mild, transient, hypohydration does not affect the acquisition and 54 decay of HA, or endurance performance parameters. Irrespective of hydration, trained 55 individuals require >5 days to optimise HA

Incidence of sleep disorders in patients with Alzheimer disease

Objetivo: Determinar a incidência de distúrbios do sono em seguimento de 1 a 4 anos em pacientes com demência diagnosticada na primeira consulta, além de analisar características demográfcas e comorbidades associadas. Métodos: Cento e vinte e dois idosos com 60 anos ou mais e com o diagnóstico de demência (Alzheimer e outras) foram seguidos em um centro de referência geriátrico para demência. O protocolo clínico incluiu entrevista com o paciente e o cuidador, exame físico, laboratorial e de imagem. Os critérios para diagnóstico dos distúrbios do sono incluíram queixa de insônia pelo paciente ou cuidador utilizando o item sobre comportamentos noturnos do Inventário Neuropsiquiátrico. Resultados: A densidade de incidência de distúrbios do sono foi de 18,7/100 pessoas/ano. O risco de desenvolver distúrbios do sono no primeiro e quarto anos de seguimento foi de 9,8% e 50,9%, respectivamente. Análise multivariada de Cox revelou que o nível educacional menor que 8 anos e a presença de agressividade na primeira consulta foram fatores preditores independentes para desenvolver distúrbios do sono no seguimento, aumentando o risco em 3,1 (IC95%: 1,30-9,22) e 2,1 (IC95%: 1,16-4,17) vezes, respectivamente. Conclusão: A incidência de distúrbios do sono em pacientes dementes foi elevada e, neste estudo, particularmente associada ao baixo nível educacional e à agressividade na admissão. ____________________________________________________________________________________ ABSTRACTObjective: To determine the incidence of sleep disorder at a follow-up examination from 1 to 4 years, in demented patients diagnosed at frst visit, besides analyzing associated demographic and comorbidities characteristics. Methods: A total of 122 elderly patients aged 60 years or older and diagnosed with dementia (Alzheimer and other) were followed in a reference geriatric center for dementia. The clinical protocols included interviews with patient and caregiver, complete physical examination, laboratory and imaging tests. Criteria for the diagnosis of sleep disorder included complain of insomnia from the patient or caregiver using the Neuropsychiatric Inventory nighttime. Results: The incidence density of sleep disorder among dements was 18.7/100 person/years. The risk of developing sleep disorder within the frst and fourth years of follow-up was 9.8% and 50.9%, respectively. Multivariate Cox regression analysis revealed that educational level less than 8 years and report of aggressiveness at baseline were an independent predictor of sleep disorder, increased risk in 3.1 (95%CI: 1.30-9.22) and 2.1 times (95%CI: 1.16-4.17), respectively. Conclusion: The incidence of sleep disorder in demented patients was elevated, and was particularly associated to low educational level and aggressiveness at admission

Electronics Shielding and Reliability Design Tools

It is well known that electronics placement in large-scale human-rated systems provides opportunity to optimize electronics shielding through materials choice and geometric arrangement. For example, several hundred single event upsets (SEUs) occur within the Shuttle avionic computers during a typical mission. An order of magnitude larger SEU rate would occur without careful placement in the Shuttle design. These results used basic physics models (linear energy transfer (LET), track structure, Auger recombination) combined with limited SEU cross section measurements allowing accurate evaluation of target fragment contributions to Shuttle avionics memory upsets. Electronics shielding design on human-rated systems provides opportunity to minimize radiation impact on critical and non-critical electronic systems. Implementation of shielding design tools requires adequate methods for evaluation of design layouts, guiding qualification testing, and an adequate follow-up on final design evaluation including results from a systems/device testing program tailored to meet design requirements

Development of an Extra-vehicular (EVA) Infrared (IR) Camera Inspection System

Designed to fulfill a critical inspection need for the Space Shuttle Program, the EVA IR Camera System can detect crack and subsurface defects in the Reinforced Carbon-Carbon (RCC) sections of the Space Shuttle s Thermal Protection System (TPS). The EVA IR Camera performs this detection by taking advantage of the natural thermal gradients induced in the RCC by solar flux and thermal emission from the Earth. This instrument is a compact, low-mass, low-power solution (1.2cm3, 1.5kg, 5.0W) for TPS inspection that exceeds existing requirements for feature detection. Taking advantage of ground-based IR thermography techniques, the EVA IR Camera System provides the Space Shuttle program with a solution that can be accommodated by the existing inspection system. The EVA IR Camera System augments the visible and laser inspection systems and finds cracks and subsurface damage that is not measurable by the other sensors, and thus fills a critical gap in the Space Shuttle s inspection needs. This paper discusses the on-orbit RCC inspection measurement concept and requirements, and then presents a detailed description of the EVA IR Camera System design

Reliability-Based Electronics Shielding Design Tools

Shielding design on large human-rated systems allows minimization of radiation impact on electronic systems. Shielding design tools require adequate methods for evaluation of design layouts, guiding qualification testing, and adequate follow-up on final design evaluation

Empreendedorismo feminino: um estudo exploratório sobre a perspetiva de mulheres brasileiras empreendedoras em Portugal

O empreendedorismo foi, durante muito tempo, relacionado apenas com o universo masculino e só depois da década de 70 é que se começou a investigar também as mulheres empreendedoras. A grande maioria dos estudos encontrados centram-se em comparações entre homens e mulheres empreendedores/as, bem como nas motivações que fazem as mulheres empreender e as dificuldades e limitações que elas encontram ao procurar empreender. Além disso, percebe-se a pouca investigação existente sobre outros assuntos que perpassam as mulheres empreendedoras, sendo ainda menor a investigação com mulheres empreendedoras imigrantes. É a partir deste facto que a presente investigação se tornou pertinente: investigar as mulheres brasileiras que estão a empreender em Portugal. Então, procurou-se conhecer os motivos que as fizeram empreender, descrever as maiores dificuldades e identificar os processos psicossociológicos mais salientes. Foi desenvolvido um guião semiestruturado, utilizado na realização de 13 entrevistas a mulheres brasileiras empreendedoras em Portugal, com idades entre os 20 e os 48 anos. Os resultados revelaram cinco grandes temas, centrados: nas motivações que perpassam as mulheres a empreender; nas adversidades que estas empreendedoras enfrentam; no ser imigrante; no ser empreendedora; e no ser mulher. Em geral, percebe-se que as participantes iniciaram o empreendimento por uma realização pessoal. As dificuldades destacadas foram a pandemia da Covid-19 e as diferenças culturais existentes entre Brasil e Portugal. Mas estas são mulheres fortes e resilientes, e mesmo que o facto de ser imigrante e ser mulher infira no empreendimento, elas procuram sempre o melhor para a sua empresa e para os/as clientes.Entrepreneurship was, for a long time, related only to the male universe and it was only after the 1970s that women entrepreneurs also began to be investigated. Most of the studies found focus on comparisons between men and women entrepreneurs, as well as on the motivations that make women entrepreneurs and the difficulties and limitations they encounter when seeking to become entrepreneurs. Furthermore, it is noticeable how little research there is on other subjects that permeate women entrepreneurs, and there is even less research on immigrant women entrepreneurs. It is based on this fact that the present research became pertinent: to investigate Brazilian women who are entrepreneurs in Portugal. To this end, we sought to know the reasons that made them become entrepreneurs, describe their biggest difficulties, and identify the psychosociological processes most prominent in them. A semi-structured script was developed and used in 13 interviews with Brazilian women entrepreneurs in Portugal, aged between 20 and 48 years old. The results revealed five major themes: the motivations that drive women to become entrepreneurs; the adversities that these entrepreneurs face; being an immigrant; being an entrepreneur; and being a woman. In general, it is perceived that the participants started the enterprise for personal fulfillment. The difficulties highlighted were the Covid-19 Pandemic and the cultural differences between Brazil and Portugal. They are strong and resilient women, and even though being an immigrant and being a woman influences the enterprise, they always seek the best for their company and for the clients

O golpe do Estado Novo (1937)

Bibliografia: p. 189

The effects of single versus twice daily short term heat acclimation on heat strain and 3000 m running performance in hot, humid conditions

Endurance performances are impaired under conditions of elevated heat stress. Short term heat acclimation (STHA) over 4-6 days can evoke rapid adaptation, which mitigate decrements in performance and alleviate heat strain. This study investigated the efficacy of twice daily heat acclimation (TDHA) compared to single session per day heat acclimation (SDHA) and normothermic training, at inducing heat acclimation phenotype and its impact upon running performance in hot, humid conditions.Twenty one, moderately trained males were matched and assigned to three groups; SDHA (mean±SD) (peak oxygen consumption [V˙O2peak] 45.8±6.1 mL kg-1 min-1, body mass 81.3±16.0 kg, stature 182±3 cm), TDHA (46.1±7.0 mL kg-1 min-1, 80.1±11.9 kg, 178±4 cm) or control (CON) (47.1±3.5 mL kg-1 min-1, 78.6±16.7 kg, 178±4 cm). Interventions consisted of 45 min cycling at 50% V˙O2peak, once daily for 4d (SDHA) and twice daily for 2d (TDHA), in 35 °C, 60% relative humidity (RH), and once daily for 4 days (CON) in 21 °C, 40% RH. Participants completed a pre- and post-intervention 5 km treadmill run trial in 30 °C, 60% RH, where the first 2 km were fixed at 40% V˙O2peak and the final 3 km was self-paced.No statistically significant interaction effects occurred within- or between-groups over the 2-4 days intervention. While within-group differences were found in physiological and perceptual measures during the fixed intensity trial post-intervention, they did not statistically differ between-groups. Similarly, TDHA (-36±34 s [+3.5%]) and SDHA (-26±28 s [+2.8%]) groups improved 3 km performances (p=0.35), but did not differ from CON (-6±44 s [+0.6%]).This is the first study to investigate the effects of HA twice daily and compare it with traditional single session per day STHA. These STHA protocols may have the ability to induce partial adaptive responses to heat stress and possibly enhance performance in environmentally challenging conditions, however, future development is warranted to optimise the administration to provide a potent stimuli for heat adaptation in athletic and military personnel within a rapid regime

Hydration and blood volume effects on human thermoregulation in the heat: Space applications

Astronauts exposed to prolonged weightlessness will experience deconditioning, dehydration, and hypovolemia which all adversely affect thermoregulation. These thermoregulatory problems can be minimized by several countermeasures that manipulate body water and vascular volumes. USARIEM scientists have extensively studied dehydration effects and several possible countermeasures including hyperhydration, plasma and erythrocyte volume expansion. This paper reviews USARIEM research into these areas

Heat and Hypoxic Acclimation Increase Monocyte Heat Shock Protein 72 but Do Not Attenuate Inflammation following Hypoxic Exercise

Acclimation to heat or hypoxic stress activates the heat shock response and accumulation of cytoprotective heat shock proteins (HSPs). By inhibiting the NF-κB pathway HSP72 can preserve epithelial function and reduce systemic inflammation. The aim of this study was to determine the time course of mHSP72 accumulation during acclimation, and to assess intestinal barrier damage and systemic inflammation following hypoxic exercise. Three groups completed 10 × 60-min acclimation sessions (50% normoxic VO2peak) in control (n = 7; 18°C, 35% RH), hypoxic (n = 7; FiO2 = 0.14, 18°C, 35% RH), or hot (n = 7; 40°C, 25% RH) conditions. Tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), interleukin 10 (IL-10), and intestinal fatty acid binding protein (I-FABP) were determined at rest and following a cycling normoxic stress test (NST; ~2 weeks before acclimation), pre-acclimation hypoxic stress test (HST1; FiO2 = 0.14, both at 50% normoxic VO2peak; ~1 week before acclimation) and post-acclimation HST (48 h; HST2). Monocyte HSP72 (mHSP72) was determined before and after exercise on day 1, 3, 5, 6, and 10 of acclimation. Accumulation of basal mHSP72 was evident from day 5 (p &lt; 0.05) of heat acclimation and increased further on day 6 (p &lt; 0.01), and day 10 (p &lt; 0.01). In contrast, basal mHSP72 was elevated on the final day of hypoxic acclimation (p &lt; 0.05). Following the NST, plasma TNF-α (–0.11 ± 0.27 ng.mL−1), IL-6 (+0.62 ± 0.67 ng.mL−1) IL-10 (+1.09 ± 9.06 ng.mL−1) and I-FABP (+37.6 ± 112.8 pg.mL−1) exhibited minimal change. After HST1, IL-6 (+3.87 ± 2.56 ng.mL−1), IL-10 (+26.15 ± 26.06 ng.mL−1) and I-FABP (+183.7 ± 182.1 pg.mL−1) were elevated (p &lt; 0.01), whereas TNF-α was unaltered (+0.08 ± 1.27; p &gt; 0.05). A similar trend was observed after HST2, with IL-6 (+3.09 ± 1.30 ng.mL−1), IL-10 (+23.22 ± 21.67 ng.mL−1) and I-FABP (+145.9 ±123.2 pg.mL−1) increased from rest. Heat acclimation induces mHSP72 accumulation earlier and at a greater magnitude compared to matched work hypoxic acclimation, however neither acclimation regime attenuated the systemic cytokine response or intestinal damage following acute exercise in hypoxia