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In recent decades, economic activity has become increasingly concentrated in major global metropolises. Yet, the rise of working from home threatens this dominance of cities. Using multiple high-frequency datasets on spending, commuting, migration, and housing, we provide global evidence that remote work has dispersed economic activity away from city centers. We label this the "Donut Effect," which is much larger and more persistent in cities with high levels of remote work. Using detailed household microdata from the United States, we show that three-fifths of households that left city centers in big cities moved to the suburbs of the same city. This is likely explained by the rise of hybrid work, in which employees still commute to the office a few days a week. The enduring popularity of hybrid work into 2024 suggests that the Donut Effect will persist while also leaving broader metropolitan areas intact.
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Ciudades , Humanos , Estados Unidos , Vivienda/economía , Teletrabajo , Población Urbana , Transportes , Empleo/estadística & datos numéricosRESUMEN
Molybdenum disulfide (MoS2 ) is a promising candidate for electronic and optoelectronic applications. However, its application in light harvesting has been limited in part due to crystal defects, often related to small crystallite sizes, which diminish charge separation and transfer. Here we demonstrate a surface-engineering strategy for 2D MoS2 to improve its photoelectrochemical properties. Chemically exfoliated large-area MoS2 thin films were interfaced with eight molecules from three porphyrin families: zinc(II)-, gallium(III)-, iron(III)-centered, and metal-free protoporphyrinâ IX (ZnPP, GaPP, FePP, H2 PP); metal-free and zinc(II) tetra-(N-methyl-4-pyridyl)porphyrin (H2 T4, ZnT4); and metal-free and zinc(II) tetraphenylporphyrin (H2 TPP, ZnTPP). We found that the photocurrents from MoS2 films under visible-light illumination are strongly dependent on the interfacial molecules and that the photocurrent enhancement is closely correlated with the highest occupied molecular orbital (HOMO) levels of the porphyrins, which suppress the recombination of electron-hole pairs in the photoexcited MoS2 films. A maximum tenfold increase was observed for MoS2 functionalized with ZnPP compared with pristine MoS2 films, whereas ZnT4-functionalized MoS2 demonstrated small increases in photocurrent. The application of bias voltage on MoS2 films can further promote photocurrent enhancements and control current directions. Our results suggest a facile route to render 2D MoS2 films useful for potential high-performance light-harvesting applications.
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BACKGROUND: The endocannabinoid system is active in nervous and immune cells and involves the expression of two cannabinoid receptor genes (CB1 and CB2), along with endogenous endocannabinoid ligands, 2-arachidonoyl glycerol (2-AG) and arachidonoyl ethanolamide (anandamide), and their synthetic enzymes. Cannabidiol (CBD) is a non-intoxicating exogenous cannabinoid agonist derived from plants that, at high doses, has received FDA approval as an anticonvulsant for epileptic seizures, and at low doses is marketed as a food-grade supplement for improved mental health, sleep quality, and immunological function. At present, the predominance of published CBD clinical research has focused on ameliorative or disease-specific intervention, with few trials investigating CBD effects in healthy populations. METHODS: This clinical study aimed to investigate the effects of 8 weeks of 50 mg oral CBD on mental health, sleep quantity and quality, and immune cell function in healthy, college-aged individuals. Twenty-eight participants (average age 25.9 ± 6.1 y) were randomized to receive either daily oral capsules of 50 mg of CBD (CB, n = 14) or a calorie-matched placebo (CN, n = 14). Participants completed pre- and post-intervention assessments, including anthropometric measurements, mental health surveys, sleep analysis, and immunological function assessments. RESULTS: After completing the 8-week intervention, there were no significant changes in body weight and BMI (CN: 1.09 ± 0.89%: CB: 1.41 ± 1.07%), or body fat percentage (CN: 9.01 ± 7.51%: CB: 8.57 ± 7.81%), respectively (values are % change pre to post, p > 0.05). There were also no significant differences between CB and CN groups with respect to mental health measures, sleep quantity, or circulating immunophenotype as a result of the intervention. However, the CB group experienced significant improvements in sleep quality measured objectively using a sleep questionnaire (p = 0.0023) and enhanced Natural Killer (NK) immune cell function assessed in situ (p = 0.0125). CONCLUSIONS: Eight weeks of daily 50 mg CBD may improve sleep quality, and NK immunosurveillance in healthy, younger adults.
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Cannabidiol , Adulto , Humanos , Adulto Joven , Cannabidiol/farmacología , Endocannabinoides , Calidad del Sueño , Suplementos DietéticosRESUMEN
BACKGROUND: There is a lack of research on the effects of cannabidiol (CBD) on health-related fitness, physical activity, cognitive health, psychological wellbeing, and concentrations of C-reactive protein (CRP) in healthy individuals. CBD has potential anti-inflammatory and neuroprotective effects. METHODS: This study aimed to investigate the effects of 8 weeks of CBD on the above-mentioned measures in healthy individuals. Forty-eight participants were randomized into two groups receiving either oral capsules of 50 mg of CBD or a calorie-matched placebo daily. Participants completed pre- and post-intervention assessments, including blood draws, body composition, fitness, physical activity, and self-reported surveys. RESULTS: There were no significant differences between groups regarding body composition, aerobic fitness, muscular strength, physical activity, cognitive health, psychological wellbeing, and resting CRP concentrations. However, the placebo group experienced a decline in mean peak power and relative peak power compared to the CBD group. CONCLUSIONS: The results suggest that 8 weeks of CBD supplementation may prevent declines in anaerobic fitness over time. However, long-term CBD supplementation may not be beneficial for altering measures of health-related fitness, mental health, and inflammation in healthy individuals.
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Cannabidiol , Humanos , Adulto , Cannabidiol/farmacología , Inflamación/tratamiento farmacológico , Método Doble Ciego , Estado de SaludRESUMEN
Curcumin may improve athletic performance through a reduction in inflammation following exercise and improve mental states of well-being. The purpose of this investigation was to explore the effects of a 14 day HIIT intervention and oral supplementation with Longvida® optimized curcumin on athletic performance, lactate response, and well-being. Sixteen males and twenty females participated in a double-blinded, randomized, placebo-controlled trial to explore the effects of Longvida(R) optimized curcumin (1.0 g/day) and or a placebo (PLA) taken daily during a 14 day HIIT protocol. Participants were randomized into two groups, then evaluated in three groups, curcumin-fast (CURF), curcumin-slow (CURS) and placebo. Curcumin-fast and curcumin-slow were separated by their 16.1 km cycling time trial performance (TT) with CURF and CURS determined by a TT <30 min and >30 min at the pre intervention time point, respectively. Cycling time-trial performance, blood lactate response, and well-being assessments were determined at pre and post 14 day HIIT intervention time points. Blood lactate was recorded at baseline, 8.01 km, 15.1 km, and 1 min post, and 4 min post of the pre and post intervention TT. Following the internvetion, CONP and CURS experienced with 8.15% and 5.04% improvements in TT performance times, while CURF experienced a 0.57% improvement in TT performance time. No changes were observed with respect to other measures. When curcumin is taken daily in conjunction with 14 days of HIIT on a cycle ergometer, cycling performance in either well trained or more recreationally trained athletes is not impaired. Although the improvements in TT performance were not stasticially significant, they are noteworthy.