Uncoupling between cerebral perfusion and oxygenation during incremental exercise in an athlete with postconcussion syndrome: a case report

High‐intensity exercise may pose a risk to patients with postconcussion syndrome (PCS) when symptomatic during exertion. The case of a paralympic athlete with PCS who experienced a succession of convulsion‐awakening periods and reported a marked increase in postconcussion symptoms after undergoing a graded symptom‐limited aerobic exercise protocol is presented. Potential mechanisms of cerebrovascular function failure are then discussed

The physiological burden of the 6-minute walk test compared with cardiopulmonary exercise stress test in patients with severe aortic atenosis

Background Management of aortic stenosis (AS) relies on symptoms. Exercise testing is recommended for asymptomatic patients with significant AS but is often experienced as forbidding and/or technically unrealistic for patients who are often frail, deconditioned, and intimidated by the exercise test. We compared the physiological burden assessed with gas exchange assessments to gauge and respiratory exchange ratio (RER) of a 6-minute walk test (6MWT) to a cardiopulmonary exercise stress test (CPET) in patients with severe AS. peak oxygen utilization Methods Adults with equivocal symptoms and severe AS (1-aortic valve area [AVA] ≤ 1.0 cm2 or AVA index ≤ 0.6 cm2/m2, 2-peak aortic jet velocity ≥ 4.0 m/sec, 3-mean transvalvular pressure gradient ≥ 40 mm Hg by rest or dobutamine stress echocardiography, or 4-aortic valve calcification ≥ 1200 in women or ≥ 2000 AU in men) were studied. All participants completed both a 6MWT and symptom-limited progressive bicycle exercise testing. Breath-by-breath gas analysis and 12-lead electrocardiography were completed during 6MWT and CPET. Results: Eleven patients were studied. Patients walked on average 330 ± 75 m during the 6MWT and achieved a maximal workload of 48 ± 14 watts during the CPET. During the 6MWT, peak maximal oxygen uptake (O2peak) was 12.8 ± 2.5 vs 10.8 ± 4.2 mL/kg/min during the CPET. Respiratory exchange ratio exceeded 1.1 in both the 6MWT and CPET indicating similarly high exertion. Compared with the CPET, a larger proportion of the 6MWT was performed at a high intensity level (78% ± 28% vs 33% ± 24% at > 85% V̇O2peak; P = 0.004). Conclusions The 6MWT with breath-by-breath gas analysis was well tolerated and able to achieve a physiological intense RER and O2peak that are similar to symptom-limited CPET in patients with severe AS.Introduction La prise en charge de la sténose aortique (SA) dépend des symptômes. L’épreuve d’effort est recommandée aux patients asymptomatiques qui ont une SA significative, mais elle est souvent perçue comme dangereuse et/ou théoriquement irréaliste chez ces patients qui sont souvent fragiles, en mauvaise forme et craintifs par l’épreuve d’effort. Nous avons comparé le fardeau physiologique calculé par la consommation maximale de l’oxygène (O2max) et le quotient respiratoire (QR) d’un test de marche de 6 minutes (TM6) et d'une épreuve d’effort maximal chez des patients avec une SA sévère. Méthodes Tous les patients présentaient une SA symptomatique et sévère (1-aire valvulaire aortique [AVA] ≤ 1,0 cm2 ouAVA ≤ 0,6 cm2/m2, 2-une vélocité maximale du flux aortique ≥ 4,0 m/sec, 3-un gradient de pression transvalvulaire moyen ≥ 40 mmHg au repos ou à l’échocardiographie à l’effort sous dobutamine ou 4-une calcification valvulaire aortique (AU) ≥ 1200 chez les femmes ou ≥ 2000 AU chez les hommes). Les participants ont effectué un TM6 et une ’épreuve d’effort maximal de type rampe sur vélo. L’analyse des échanges gazeux respiration par respiration et un électrocardiogramme à 12 dérivations ont été effectués durant le TM6 et l'épreuve d'effort maximal. Résultats Un total de 11 patients ont participé à l'étude. Les patients ont marché en moyenne 330 ± 75 m durant le TM6 et ont atteint une charge de travail maximale de 48 ± 14 watts durant l’épreuve d'effort maximal. Durant le TM6, le O2max était de 12,8 ± 2,5 vs 10,8 ± 4,2 ml/kg/min durant l’épreuve d'effort maximal. Le QR était supérieur à 1,1 au TM6 ainsi qu'à l’épreuve d'effort maximal. Comparativement à l’épreuve d'effort maximal, un pourcentage plus important au TM6 a été réalisée à une intensité élevée (78 % ± 28 % vs 33 % ± 24 % à > 85 % V̇O2max; P = 0,004). Conclusions Le TM6 avec mesure directe des échanges gazeux était bien toléré et susceptible d’atteindre des valeurs physiologiques d'intensité élevée pour le QR et le O2max. Les valeurs atteintes au TM6 étaient semblables à celles de l'épreuve d'effort maximal chez les patients avec une SA sévère

IMPROVED METHODS FOR CHARACTERIZING INDUSTRIES IN REGIONAL ECONOMICS

This dissertation consists of three separate papers each of which merges the concepts of industrial organization, economic accounts, and regional economics. The first paper develops and implements a technique for eliminating aggregation bias in input-output accounts and reduces overall bias in the associated regional models based on such accounts. By regressing an industrial sectors’ intermediate material inputs of production on their labor inputs, a list of labor coefficients is obtained. Those labor coefficients are then applied to an industrial sectors’ constituent 6-digit industry labor inputs, provided by the Bureau of Labor Statistics. This process estimates a 6-digit industry’s intermediate material inputs and effectively disaggregates the parent sector.The second paper analyzes when central place theory and applied gravity models predict inconsistent trade patterns to one another. By creating a measure of the discrepancy between the central place trade pattern and the gravity model trade pattern we can isolate regions within a geographical space that minimize the discrepancy. The regions that are isolated from the larger geographical space act as functional economic areas that are modestly consistent with both the central place theories of industry location and gravity trade models. Because the regions describe an economic geography rather than a political or geological geography they are more appropriate for conducting economic activity analysis.The third and final paper looks at the increasing returns to scale that firms within an industry receive from agglomerating, or co-locating, in a particular region. Current research on the topic has struggled to isolate the sources of the increasing returns for various industries because the potential sources all results in a similar functional representation. This problem is often referred to as an issue of Marshallian equivalence. This research provides insight into this issue by looking at industries that are deagglomeration and monitoring how the returns to scale of labor productivity evolve over time

An economic model of wineries and enotourism

This paper uses a theoretical model to analyze the interaction between general wine sales and enotourism since many wineries sell wine through wine tours as well as wine to non-tourists. We assume that consumers of wine tours, or enotourists, are wine connoisseurs whereas naive wine drinkers drive non-tourism sales. In our model, enotourists use wine tours to judge the quality of the wine, which forms a reputation that is then used by naive wine consumers. We show that wineries may want to decrease (increase) the price of wine via enotourism if their quality is higher (lower) than expected. We analyze this under both exogenous and endogenous quality. We also show that if wineries share a collective reputation, then minimum quality standards can benefit all wineries. Keywords: Wine, Enotourism, Collective reputatio

COURBE INTRINSEQUE DE LA GLACE EN COMPRESSION

Les résultats présentés dans cet article ont été obtenus à partir d'essais effectués sur des échantillons de glace de différentes origines (glace d'eau douce, glace d'iceberg et glace légèrement saline). Les échantillons ont été testés à taux de déformation constant. Certains ont été soumis à une pression de confinement pouvant atteindre 70 MPa. Les résultats ont été analysés de manière à formuler une courbe intrinsèque appropriée à la glace. L'avantage principal de cette nouvelle formulation réside dans le fait qu'elle prévoit le changement de phase de la glace en fonction de la pression hydrostatique exercée sur l'échantillon.This paper presents some information obtained from tests performed on fresh water, iceberg and low salinity granular ice. The testing program included constant strain rate uniaxial compression tests and constant strain rate confined compression tests. Maximum confining pressure reached 70 MPa. The results from the constant strain rate tests have been analysed in order to formulate a proper yield surface criterion for ice. The advantage of this new formulation lies in its ability to consider the hydrostatic pressure at which ice changes to water

Odessa Sub-area Potato Production & Processing Impacts Under an Irrigation-Water Shortage

The Odessa Sub-area lies in the second, and uncompleted, region of Washington’s Columbia Basin Water Project. Water used for irrigation in the region is currently pumped from as deep as 700 feet, and water access is steadily declining. We measure the economic losses to the potato producing region that would result from further reducing access to water for crop irrigation in the Columbia Basin. Estimated costs are adjusted for the gains in wheat production that would result as affected growers transition their land into the next best non-irrigated crop alternative in the region. Then, we move beyond the standard contribution analysis by looking not only at the net losses in production, but potential forward linked losses from potato processing plant closures

Biophysical Climate Risks and Economic Impacts for Washington State

The Washington State 2021-23 Operating Budget ESSB 5092 Sec 606(23)) funded the University of Washington Climate Impacts Group (CIG) to “provide an updated climate risk assessment designed to inform future updates to the statewide climate resilience strategy.” The UW CIG, with Washington State University IMPACT Center, compiled information on two science-based elements of climate risk: Biophysical Impacts: Projections of the magnitude and timing of changes in the climate and climate-related hazards. Expected climate changes are mapped for Washington State, summarized by county, and presented in an interactive web application for local governments and state agencies, Climate Mapping for a Resilient Washington. Economic Impacts: Case studies of the economic consequences of three key biophysical impacts — extreme heat, wildfire, drought —for the economy in Washington. This assessment of future changes in the climate and climate-related hazards, with associated economic consequences, can inform state and local plans for climate resilience and prioritization of funding for risk-reduction activities.State of Washingto