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High-Intensity Exercise in Hypoxia - Beneficial Aspects and Potential Drawbacks

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Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889454068 Year: Pages: 169 DOI: 10.3389/978-2-88945-406-8 Language: English
Publisher: Frontiers Media SA
Subject: Science (General) --- Physiology
Added to DOAB on : 2018-11-16 17:17:57
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In the past, ‘traditional’ moderate-intensity continuous training (60-75% peak heart rate) was the type of physical activity most frequently recommended for both athletes and clinical populations (cf. American College of Sports Medicine guidelines). However, growing evidence indicates that high-intensity interval training (80-100% peak heart rate) could actually be associated with larger cardiorespiratory fitness and metabolic function benefits and, thereby, physical performance gains for athletes. Similarly, recent data in obese and hypertensive individuals indicate that various mechanisms – further improvement in endothelial function, reductions in sympathetic neural activity, or in arterial stiffness – might be involved in the larger cardiovascular protective effects associated with training at high exercise intensities. Concerning hypoxic training, similar trends have been observed from ‘traditional’ prolonged altitude sojourns (‘Live High Train High’ or ‘Live High Train Low’), which result in increased hemoglobin mass and blood carrying capacity. Recent innovative ‘Live Low Train High’ methods (‘Resistance Training in Hypoxia’ or ‘Repeated Sprint Training in Hypoxia’) have resulted in peripheral adaptations, such as hypertrophy or delay in muscle fatigue. Other interventions inducing peripheral hypoxia, such as vascular occlusion during endurance/resistance training or remote ischemic preconditioning (i.e. succession of ischemia/reperfusion episodes), have been proposed as methods for improving subsequent exercise performance or altitude tolerance (e.g. reduced severity of acute-mountain sickness symptoms). Postulated mechanisms behind these metabolic, neuro-humoral, hemodynamics, and systemic adaptations include stimulation of nitric oxide synthase, increase in anti-oxidant enzymes, and down-regulation of pro-inflammatory cytokines, although the amount of evidence is not yet significant enough. Improved O2 delivery/utilization conferred by hypoxic training interventions might also be effective in preventing and treating cardiovascular diseases, as well as contributing to improve exercise tolerance and health status of patients. For example, in obese subjects, combining exercise with hypoxic exposure enhances the negative energy balance, which further reduces weight and improves cardio-metabolic health. In hypertensive patients, the larger lowering of blood pressure through the endothelial nitric oxide synthase pathway and the associated compensatory vasodilation is taken to reflect the superiority of exercising in hypoxia compared to normoxia. A hypoxic stimulus, in addition to exercise at high vs. moderate intensity, has the potential to further ameliorate various aspects of the vascular function, as observed in healthy populations. This may have clinical implications for the reduction of cardiovascular risks. Key open questions are therefore of interest for patients suffering from chronic vascular or cellular hypoxia (e.g. work-rest or ischemia/reperfusion intermittent pattern; exercise intensity; hypoxic severity and exposure duration; type of hypoxia (normobaric vs. hypobaric); health risks; magnitude and maintenance of the benefits). Outside any potential beneficial effects of exercising in O2-deprived environments, there may also be long-term adverse consequences of chronic intermittent severe hypoxia. Sleep apnea syndrome, for instance, leads to oxidative stress and the production of reactive oxygen species, and ultimately systemic inflammation. Postulated pathophysiological changes associated with intermittent hypoxic exposure include alteration in baroreflex activity, increase in pulmonary arterial pressure and hematocrit, changes in heart structure and function, and an alteration in endothelial-dependent vasodilation in cerebral and muscular arteries. There is a need to explore the combination of exercising in hypoxia and association of hypertension, developmental defects, neuro-pathological and neuro-cognitive deficits, enhanced susceptibility to oxidative injury, and possibly increased myocardial and cerebral infarction in individuals sensitive to hypoxic stress. The aim of this Research Topic is to shed more light on the transcriptional, vascular, hemodynamics, neuro-humoral, and systemic consequences of training at high intensities under various hypoxic conditions.

Neonatal Screening for Critical Congenital Heart Defects

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ISBN: 9783039210480 / 9783039210497 Year: Pages: 98 DOI: 10.3390/books978-3-03921-049-7 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Social Sciences --- Sociology
Added to DOAB on : 2019-06-26 08:44:06
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Critical congenital heart defects (CCHDs) are potentially life-threatening malformations that remain a significant cause of neonatal mortality and morbidity. Failure to diagnose these conditions shortly after birth may result in acute cardiovascular collapse and death. The identification of CCHDs by routine newborn clinical examination is routine in many countries, but consistently misses over a third of cases, and, although antenatal ultrasound screening can be very effective in early diagnosis, the provision and accuracy of ultrasound screening is highly variable. As most CCHDs present with mild cyanosis (hypoxaemia), which is frequently clinically undetectable, pulse oximetry is a rapid, simple, painless method of accurately identifying hypoxaemia, which has gained popularity as a screen for CCHD. This Special Issue of the International Journal of Neonatal Screening, devoted to ""Neonatal Screening for Critical Congenital Heart Defects (CCHDs)"", will consider the evidence for CCHD screening with pulse oximetry, the acceptability and cost-effectiveness of this intervention, the additional non-cardiac conditions which it may also identify, and international experiences of introducing CCHD screening across the globe.

The Close Linkage between Nutrition and Environment through Biodiversity and Sustainability: Local Foods, Traditional Recipes and Sustainable Diets

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ISBN: 9783039213832 / 9783039213849 Year: Pages: 216 DOI: 10.3390/books978-3-03921-384-9 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General) --- Biology --- Nutrition and Food Sciences
Added to DOAB on : 2019-12-09 11:49:16
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The Close Linkage between Nutrition and Environment through Biodiversity and Sustainability: Local Foods, Traditional Recipes, and Sustainable Diets” is focused on the close correlation between the potential benefits and “functional role” of food and territory, and it includes papers on the characterization of local foods and traditional recipes as well as on the promotion of traditional dietary patterns and sustainable diets.

Keywords

Italian garlic --- carbohydrates --- fructans --- dietary fibre --- soluble sugars --- cultivar --- environmental conditions --- agave sap --- actinomycetes --- anticancer activity --- saponins --- metabolomics --- ecosystem goods and services --- environmental sustainability --- livelihood needs --- Schinziophyton rautanenii --- Southern Africa --- sustainable development goals --- sustainable diets --- alkaloids --- antimicrobial activity --- germplasm --- Klebsiella --- landraces --- lupanine --- Pseudomonas --- varieties --- traditional food --- antimicrobial --- bioassay --- PIRG --- fractions --- consumer culture theory --- post millennials --- cheese --- loyalty --- Cyprus --- traditional food --- traditional sausages --- conventional sausages --- traditional hams --- conventional hams --- traditional meat products --- pork --- fatty acids --- mountain --- sustainability --- altitude --- food --- health --- FTIR-ATR --- traditional Italian recipes --- chemometrics --- PCA --- Olea europaea L. --- olive oil --- geographical origin --- processing system --- harvesting time --- olive oil quality --- fatty acid composition --- sensorial evaluation --- consumer preferences --- agro-ecology biodiversity --- climate resilience --- health --- local foods --- bioactive components --- traditional recipes --- traditional dietary patterns --- edible plants --- Mediterranean --- innovative gastronomy --- tetraploid wheat --- metallomics --- macronutrients --- micronutrients --- plants adaptability --- Provolone del Monaco --- traditional foods --- biodiversity --- sustainability --- nutritional composition --- bioactive components --- typical/local foods --- environmental and socio-demographic factors --- traditional recipes --- sustainable diets --- traditional dietary patterns --- Food Composition Databases

Drones for Biodiversity Conservation and Ecological Monitoring

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ISBN: 9783039219803 / 9783039219810 Year: Pages: 176 DOI: 10.3390/books978-3-03921-981-0 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General)
Added to DOAB on : 2020-01-07 09:08:26
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Unmanned aerial vehicles (UAV) have already become an affordable and cost-efficient tool to quickly map a targeted area for many emerging applications in the arena of ecological monitoring and biodiversity conservation. Managers, owners, companies, and scientists are using professional drones equipped with high-resolution visible, multispectral, or thermal cameras to assess the state of ecosystems, the effect of disturbances, or the dynamics and changes within biological communities inter alia. We are now at a tipping point on the use of drones for these type of applications over natural areas. UAV missions are increasing but most of them are testing applicability. It is time now to move to frequent revisiting missions, aiding in the retrieval of important biophysical parameters in ecosystems or mapping species distributions. This Special Issue shows UAV applications contributing to a better understanding of biodiversity and ecosystem status, threats, changes, and trends. It documents the enhancement of knowledge in ecological integrity parameters mapping, long-term ecological monitoring based on drones, mapping of alien species spread and distribution, upscaling ecological variables from drone to satellite images: methods and approaches, rapid risk and disturbance assessment using drones, mapping albedo with UAVs, wildlife tracking, bird colony and chimpanzee nest mapping, habitat mapping and monitoring, and a review on drones for conservation in protected areas.

Remote Sensing of Leaf Area Index (LAI) and Other Vegetation Parameters

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ISBN: 9783039212392 / 9783039212408 Year: Pages: 334 DOI: 10.3390/books978-3-03921-240-8 Language: eng
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General)
Added to DOAB on : 2019-12-09 11:49:15
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Monitoring of vegetation structure and functioning is critical to modeling terrestrial ecosystems and energy cycles. In particular, leaf area index (LAI) is an important structural property of vegetation used in many land surface vegetation, climate, and crop production models. Canopy structure (LAI, fCover, plant height, and biomass) and biochemical parameters (leaf pigmentation and water content) directly influence the radiative transfer process of sunlight in vegetation, determining the amount of radiation measured by passive sensors in the visible and infrared portions of the electromagnetic spectrum. Optical remote sensing (RS) methods build relationships exploiting in situ measurements and/or as outputs of physical canopy radiative transfer models. The increased availability of passive (radar and LiDAR) RS data has fostered their use in many applications for the analysis of land surface properties and processes, thanks also to their insensitivity to weather conditions and the capability to exploit rich structural and textural information. Data fusion and multi-sensor integration techniques are pressing topics to fully exploit the information conveyed by both optical and microwave bands.

Keywords

conifer forest --- leaf area index --- smartphone-based method --- canopy gap fraction --- terrestrial laser scanning --- forest inventory --- density-based clustering --- forest aboveground biomass --- root biomass --- tree heights --- GLAS --- artificial neural network --- allometric scaling and resource limitation --- structure from motion (SfM) --- 3D point cloud --- remote sensing --- local maxima --- fixed tree window size --- managed temperate coniferous forests --- point cloud --- spectral information --- structure from motion (SfM) --- unmanned aerial vehicle (UAV) --- chlorophyll fluorescence (ChlF) --- drought --- Mediterranean --- photochemical reflectance index (PRI) --- photosynthesis --- R690/R630 --- recovery --- BAAPA --- remote sensing --- household survey --- forest --- farm types --- automated classification --- sampling design --- adaptive threshold --- over and understory cover --- LAI --- leaf area index --- EPIC --- simulation --- satellite --- MODIS --- biomass --- evaluation --- southern U.S. forests --- VIIRS --- leaf area index (LAI) --- Fraction of Photosynthetically Active Radiation absorbed by vegetation (FPAR) --- MODIS --- consistency --- uncertainty --- evaluation --- downscaling --- Pléiades imagery --- unmanned aerial vehicle --- stem volume estimation --- remote sensing --- clumping index --- leaf area index --- trunk --- terrestrial LiDAR --- HemiView --- forest above ground biomass (AGB) --- polarization coherence tomography (PCT) --- P-band PolInSAR --- tomographic profiles --- canopy closure --- global positioning system --- hemispherical sky-oriented photo --- signal attenuation --- geographic information system --- digital aerial photograph --- aboveground biomass --- leaf area index --- photogrammetric point cloud --- recursive feature elimination --- machine-learning --- forest degradation --- multisource remote sensing --- modelling aboveground biomass --- random forest --- Brazilian Amazon --- validation --- phenology --- NDVI --- LAI --- spectral analyses --- European beech --- altitude --- forests biomass --- remote sensing --- REDD+ --- random forest --- Tanzania --- RapidEye

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