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1. Self-reported and biometrically measured hot flashes in relation to ambient temperature and humidity.

   Sievert, Lynnette L; Shreyer, Sofiya S; Brown, Daniel E. (December 2022, Menopause)

   Self-reported and biometrically measured hot flashes in relation to ambient temperature and humidity Lynnette L. Sievert, PhD1, Sofiya Shreyer, MA,1 Daniel E. Brown, PhD2 1Anthropology, UMass Amherst, MA; 2Anthropology, University of Hawaii at Hilo, HI Objective: Warm ambient temperatures provoke hot flashes in the laboratory, but outside the laboratory the temperature to hot flash relationship is less consistent. A study in Bangladesh and London found that temperature and humidity at 12:00 and 18:00 were not associated with self-reported or biometrically measured hot flashes. However, in Spain and three South American countries, higher temperatures and humidities were associated with more frequent and problematic hot flashes. The study reported here differs from previous work in that we asked women to carry an ambulatory temperature and humidity monitor while wearing an ambulatory hot flash monitor. The purpose of this study was to examine the relationship between concurrent temperature, humidity, and hot flash experience. We hypothesized more frequent hot flashes with higher ambient temperatures. Design: Women aged 45 to 55 years were drawn from western Massachusetts for an ongoing cross-sectional study (n=195) from October through April (2019-2023). Exclusion criteria included use of medications that dampen hot flashes. Hot flashes were queried with a semi-structured questionnaire: During the past two weeks, have you been bothered by hot flashes (not at all, a little, somewhat, a lot)? Currently, how often do they occur (from less than 1/month to 5+ times/day, scored 0-8)? Hot flashes were also assessed by sternal skin conductance using a Biolog ambulatory hot flash monitor (3991x/1-SCL, UFI, Morro Bay, CA). Subjective hot flashes during the 24-hour study period were recorded with buttons on the hot flash monitor. Ambient temperature and humidity were continuously recorded with the GSP-6 Temperature and Humidity Data Logger Recorder (Elitech Technology, San Jose, CA). Menopausal status was categorized as pre-, peri- (change in cycle length >6 days) and post- (absence of menses for 12 months). Univariate relationships between temperature (maximum, minimum, mean), humidity (maximum, minimum, mean), and hot flashes (yes/no) were examined by t-tests. Temperature, humidity, and hot flash bothersomeness were examined by ANOVA. Pearson correlations were used to evaluate temperature, humidity, and hot flash frequencies (from the questionnaire and Biolog monitor). Logistic regression was also applied to examine temperature and humidity measures in relation to hot flashes while adjusting for menopausal status. Results: Mean ambient temperatures ranged from 16.3 to 30.1oC (mean 24.5oC, s.d. 2.8); mean humidities ranged from 18.9 to 68.6% (mean 40.8%, s.d. 9.2). Minimum temperature was positively associated with minimum (r=0.508, p<0.001) and mean (r=0.316, p<0.001) measures of humidity. Hot flash bothersomeness was described as not at all (31%), a little (23%), somewhat (23%), and a lot (24%). In univariate analyses, maximum, minimum, and mean temperatures and humidity levels were not associated with hot flashes (yes/no) or with the bothersomeness of hot flashes. Temperature measures were not correlated with current frequency of hot flashes or with the frequency of objective or subjective hot flashes during the study period. However, the current frequency of hot flashes was negatively correlated with minimum (r=-0.205, p<0.01) and mean (r=-0.196, p<0.01) levels of humidity, so that as humidity levels increased, the likelihood of hot flashes decreased. Although participants were keen to wear the monitor for 24-hours, the Biolog monitor quit during 38% of the studies. In the majority of cases, participants restarted the monitor. Compared to monitors that continued to function, monitors that quit were more likely to be worn when minimum temperatures were lower (mean 6.8oC vs. 8.9 oC, p=0.03), minimum humidity levels were lower (mean 17.2% vs. 22.6%, p<0.001), and mean humidity levels were lower (mean 37.2% vs. 43.0%, p<0.001). Conclusion: The hypothesized positive relationship between temperature and hot flashes was not supported. Instead, as humidity levels increased, the likelihood of hot flashes decreased. This preliminary study will be followed by syncing of the temperature, humidity, and hot flash data in order to study how changes in temperature and/or humidity may provoke hot flashes. Funding: NSF Grant #BCS-1848330 

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2. Plasmonic Photoelectrochemistry: In View of Hot Carriers

   https://doi.org/10.1002/adma.202006654  

   Zhang, Yuchao; Guo, Wenxiao; Zhang, Yunlu; Wei, Wei_David (May 2021, Advanced Materials)

   Abstract Utilizing plasmon‐generated hot carriers to drive chemical reactions has emerged as a popular topic in solar photocatalysis. However, a complete description of the underlying mechanism of hot‐carrier transfer in photochemical processes remains elusive, particularly for those involving hot holes. Photoelectrochemistry enables to localize hot holes on photoanodes and hot electrons on photocathodes and thus offers an approach to separately explore the hole‐transfer dynamics and electron‐transfer dynamics. This review summarizes a comprehensive understanding of both hot‐hole and hot‐electron transfers from photoelectrochemical studies on plasmonic electrodes. Additionally, working principles and applications of spectroelectrochemistry are discussed for plasmonic materials. It is concluded that photoelectrochemistry provides a powerful toolbox to gain mechanistic insights into plasmonic photocatalysis. 

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3. Evidence for the Late Arrival of Hot Jupiters in Systems with High Host-star Obliquities

   https://doi.org/10.3847/1538-3881/ac69ef  

   Hamer, Jacob H.; Schlaufman, Kevin C. (June 2022, The Astronomical Journal)

   Abstract It has been shown that hot Jupiters systems with massive, hot stellar primaries exhibit a wide range of stellar obliquities. On the other hand, hot Jupiter systems with low-mass, cool primaries often have stellar obliquities close to zero. Efficient tidal interactions between hot Jupiters and the convective envelopes present in lower-mass main-sequence stars have been a popular explanation for these observations. If this explanation is accurate, then aligned systems should be older than misaligned systems. Likewise, the convective envelope mass of a hot Jupiter’s host star should be an effective predictor of its obliquity. We derive homogeneous stellar parameters—including convective envelope masses—for hot Jupiter host stars with high-quality sky-projected obliquity inferences. Using a thin-disk stellar population’s Galactic velocity dispersion as a relative age proxy, we find that hot Jupiter host stars with larger-than-median obliquities are older than hot Jupiter host stars with smaller-than-median obliquities. The relative age difference between the two populations is larger for hot Jupiter host stars with smaller-than-median fractional convective envelope masses and is significant at the 3.6σlevel. We identify stellar mass, not convective envelope mass, as the best predictor of stellar obliquity in hot Jupiter systems. The best explanation for these observations is that many hot Jupiters in misaligned systems arrived in the close proximity of their host stars long after their parent protoplanetary disks dissipated. The dependence of observed age offset on convective envelope mass suggests that tidal realignment contributes to the population of aligned hot Jupiters orbiting stars with convective envelopes. 

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4. More Distinct Dry and Humid Heat in a Warming World

   https://doi.org/10.1029/2024EF005770  

   Coffel, Ethan D (June 2025, Earth's Future)

   The impacts of extreme heat events depend on the concurrent humidity level. Hot and dry conditions harm crops and vegetation, while hot and humid conditions are particularly dangerous for human health. Whether a place tends to experience heat waves that are hot and dry, hot and wet, or both, depends on the local correlation between temperature and humidity. This paper uses reanalysis, observational data, and climate models to show that the global temperature‐humidity correlation has steadily declined since 1981 at a somewhat faster rate than climate models simulate. This decline in the temperature‐humidity correlation has occurred because humidity is increasing less quickly (or decreasing) on days with high dry‐bulb temperatures as compared to days with high wet‐bulb temperatures. The relative drying of hot and dry days is associated with those days warming faster than hot and humid days. Overall, the decline in the temperature‐humidity correlation has exacerbated the risk from hot and dry conditions while slightly slowing increases in hot and humid conditions. 

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5. Data Center Waste Heat Reuse: An Investment Analysis

   https://doi.org/10.1115/1.4067444  

   Khalid, Rehan; Wemhoff, Aaron P; Khuc, Mai; Nayar, Ajay J; Schon, Steven (February 2025, ASME Journal of Engineering for Sustainable Buildings and Cities)

   Abstract A thermo-economic analysis (TEA) of a novel cooling and enhanced heat recovery (CEHR) system for data centers (DCs) is presented. Three financial metrics (net present value—NPV, return on investment—ROI, and payback period—PP) are calculated for hot and chilled water generation. Hot water generation uses vapor recompression to produce water at approximately 75 °C. Chilled water generation builds upon the hot water generation scenario by feeding the hot water stream into an absorption chiller. Without considering the additional costs for connecting the infrastructure with the customer, a payback period shorter than 2 years is found for a hot water generation system for a base case assuming a 10-MW data center (DC) in Philadelphia, PA, when carbon (reduction) credits are included. Chilled water generation is found to be economically unfavorable in this location. Sensitivities of economics to data center power, hot water versus chilled water generation, geographic region, and carbon credits are evaluated for five additional global locations in Europe and Asia. The economies of scale enable favorable payback periods for integrating hot water generation for facilities beyond 7 MW. Hot water generation is especially favorable in Singapore when replacing natural gas-based heating or hot water heat pumps. 

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