Design considerations for a GaAs nipi doping superlattice solar cell

A new GaAs nipi doping superlattice solar cell structure is presented, which holds promise for high efficiency coupled with very high radiation tolerance. The structure has all contacts on the unilluminated side. Design constraints are presented which this structure must satisfy in order to exhibit high efficiency and high radiation tolerance. The results of self-consistent quantum mechanical calculations are presented which show that a viable design of this cell would include relatively thick n and p layers which are fairly heavily doped

Multimedia Service Learning Partnerships

Goal: I would like to share the success of working with 30 different nonprofit, community, and campus organizations with senior electronic news and sports majors. At a time where every student has to really stand out at job interviews, a service learning project that incorporates everything they have learned in their curriculum can take them to the next level by engaging them in the community they are about to serve. Rationale: Following the tornado that devastated Tuscaloosa on April 27, 2011, I witnessed nonprofits who were held hostage by the web companies that hosted their content. They couldn\u27t make changes quickly to inform people how to help others, and they turned to social media as their fastest communication tool. I felt it was important to teach them how to control their own destiny when it came to communication in today\u27s media landscape by having my students show them how to use the skills they\u27ve learned. How It Works: For a semester, seniors partner with a nonprofit/community/campus organization where students work on a new media marketing plan. They research, interview, and investigate the real-world situation for the organization to determine the target audience they are trying to reach, the problems they are trying to solve, and the issues that need to be tackled to help them with communication and increasing their reach and leads to help the organization. Then they create media projects using photos, social media, apps, videos, and audio and create a website with a new media marketing strategy to help with the real-world situation. These are traditional broadcast news students who know how to shoot and frame subjects to industry standards, interview people for soundbites, and edit video in a short form. The New Media course presented a unique opportunity to involve students in the community while they learned how to build nonprofit brands. Results: In the last four years, nearly 100 students have worked with over 30 clients (i.e. Tuscaloosa Arts, PARA First Tee, Foster Grandparents Program, Arts \u27N Autism) in the community. Three of these projects were recognized with awards. Forest Lake, focused on the rebuilding of one of Tuscaloosa\u27s hardest hit areas and how the area was coming back two years later, won first place in the 2013 international BEA Festival of Media Arts small interactive multimedia competition. Miracle League of Tuscaloosa, which highlights the baseball league for children with physical and mental disabilities, won in the 2014 International BEA Festival of Media Arts small interactive multimedia competition. The Alberta History website project was awarded a $4,500 seed grant to enhance the website and spread the word to help people realize the sense of community they have in a city that\u27s also rebuilding from the tornado. In addition, elements from these projects have been presented at conferences, including the annual international BEA conference and the SPJ/RTDNA\u27s national conference, to help faculty from around the world learn how to include community involvement in their classes

Fake News? A Survey on Video News Releases and their Implications on Journalistic Ethics, Independence and Credibility of Broadcast News

The traditional lines between journalism and public relations are now intertwined and public relations practitioners have an influential role on the content consumers see every day in newspapers and on news broadcasts. This survey looked at video news releases and their implications about journalists’ ethics, integrity, independence and credibility. 533 participants from three different populations (average viewers, communication college students, and journalists) responded to a 54-question survey that employed two predictors (i) level of experience and (ii) years of journalism experience. The results indicated that average viewers found the use of video news releases (VNRs) more unethical than journalists and communication students, although experienced journalists believed VNR use is having an impact on journalistic independence in news. Implications are discussed

Long Duration X-Ray Flash and X-Ray Rich Gamma Ray Burst from Low Mass Population III Star

Recent numerical simulations suggest that Population III (Pop III) stars were born with masses not larger than $\sim 100 M_{\odot}$ but typically $\sim 40M_{\odot}$. By self-consistently considering the jet generation and propagation in the envelope of these low mass Pop III stars, we find that a Pop III blue super giant star has the possibility to raise a gamma-ray burst (GRB) even though it keeps a massive hydrogen envelope. We evaluate observational characters of Pop III GRBs and predict that Pop III GRBs have the duration of $\sim 10^5$ sec in the observer frame and the peak luminosity of $\sim 5 \times 10^{50} {\rm erg} {\rm sec}^{-1}$. Assuming that the $E_p-L_p$ (or $E_p-E_{\gamma, \rm iso}$) correlation holds for Pop III GRBs, we find that the spectrum peak energy falls $\sim$ a few keV (or $\sim 100$ keV) in the observer frame. We discuss the detectability of Pop III GRBs by future satellite missions such as EXIST and Lobster. If the $E_p-E_{\gamma, \rm iso}$ correlation holds, we have the possibility to detect Pop III GRBs at $z \sim 9$ as long duration X-ray rich GRBs by EXIST. On the other hand, if the $E_p-L_p$ correlation holds, we have the possibility to detect Pop III GRBs up to $z \sim 19$ as long duration X-ray flashes by Lobster.Comment: 27 pages, 7 figures, Accepted to the Astrophysical Journa

Probabilistic Evaluation of Drought in CMIP6 Simulations

As droughts have widespread social and ecological impacts, it is critical to develop long-term adaptation and mitigation strategies to reduce drought vulnerability. Climate models are important in quantifying drought changes. Here, we assess the ability of 285 CMIP6 historical simulations, from 17 models, to reproduce drought duration and severity in three observational data sets using the Standardized Precipitation Index (SPI). We used summary statistics beyond the mean and standard deviation, and devised a novel probabilistic framework, based on the Hellinger distance, to quantify the difference between observed and simulated drought characteristics. Results show that many simulations have less than error in reproducing the observed drought summary statistics. The hypothesis that simulations and observations are described by the same distribution cannot be rejected for more than of the grids based on our distance framework. No single model stood out as demonstrating consistently better performance over large regions of the globe. The variance in drought statistics among the simulations is higher in the tropics compared to other latitudinal zones. Though the models capture the characteristics of dry spells well, there is considerable bias in low precipitation values. Good model performance in terms of SPI does not imply good performance in simulating low precipitation. Our study emphasizes the need to probabilistically evaluate climate model simulations in order to both pinpoint model weaknesses and identify a subset of best-performing models that are useful for impact assessments

Understanding the Impact of Belzutifan on Treatment Strategies for Patients with VHL

Belzutifan was recently approved for the management of Von Hippel–Lindau disease (VHL). Given the morbidity of recurrent treatment, systemic therapy to reduce or eliminate the need for surgery has been long-awaited. Herein, we sought to gain insight about future utilization by surveying VHL  experts in the United States. A survey developed by members of the VHL Alliance (VHLA) Clinical Advisory Council was distributed to kidney cancer providers at VHLA and National Comprehensive Cancer Network (NCCN) centers. Surveys were administered on a secure web-based platform. A total of 60 respondents from 29 institutions participated. Urologists (50%) and medical oncologists (43%) represented the majority of participants. The majority (98%) of respondents anticipated that belzutifan’s approval would signifi-cantly change the current treatment landscape. Most reported that therapy should be continuous (76%). There was a difference in willingness to prescribe belzutifan by specialty (38% of urologists vs 91% of medical oncologists (P = 0.02). In individuals with renal tumors <3 cm, 36% would still recommend surveillance, while 36% would initiate belzutifan to prevent growth. In those with multifocal renal lesions and growth of a solitary tumor on belzutifan, 50% would proceed with only treatment of that site. In conclusion, VHL kidney cancer specialists anticipate a paradigm shift with the approval of belzutifan. Provider roles may change with movement away from surgical management. Opinions on treatment indications, such as when to initiate therapy and how to best salvage, vary widely and collaborative efforts among experts may assist in the development of clinical guidelines

The Perils of Regridding: Examples Using a Global Precipitation Dataset

Canada First Research Excellence Fund’s Global Water Futures program, the Natural Sciences and Engineering Research Council of Canada, the Canada Research Chairs program, and the Pacific Institute for Mathematical StudiesPeer ReviewedGridded precipitation datasets are used in many applications such as the analysis of climate variability/change and hydrological modeling. Regridding precipitation datasets is common for model coupling (e.g., coupling atmospheric and hydrological models) or comparing different models and datasets. However, regridding can considerably alter precipitation statistics. In this global analysis, the effects of regridding a precipitation dataset are emphasized using three regridding methods (first-order conservative, bilinear, and distance-weighted averaging). The differences between the original and regridded dataset are substantial and greatest at high quantiles. Differences of 46 and 0.13 mm are noted in high (0.95) and low (0.05) quantiles, respectively. The impacts of regridding vary spatially for land and oceanic regions; there are substantial differences at high quantiles in tropical land regions, and at low quantiles in polar regions. These impacts are approximately the same for different regridding methods. The differences increase with the size of the grid at higher quantiles and vice versa for low quantiles. As the grid resolution increases, the difference between original and regridded data declines, yet the shift size dominates for high quantiles for which the differences are higher. While regridding is often necessary to use gridded precipitation datasets, it should be used with great caution for fine resolutions (e.g., daily and subdaily), because it can severely alter the statistical properties of precipitation, specifically at high and low quantiles

Photon Pair Generation in Silicon Micro-Ring Resonator with Reverse Bias Enhancement

Photon sources are fundamental components for any quantum photonic technology. The ability to generate high count-rate and low-noise correlated photon pairs via spontaneous parametric down-conversion using bulk crystals has been the cornerstone of modern quantum optics. However, future practical quantum technologies will require a scalable integration approach, and waveguide-based photon sources with high-count rate and low-noise characteristics will be an essential part of chip-based quantum technologies. Here, we demonstrate photon pair generation through spontaneous four-wave mixing in a silicon micro-ring resonator, reporting a maximum coincidence-to-accidental (CAR) ratio of 602 (+-) 37, and a maximum photon pair generation rate of 123 MHz (+-) 11 KHz. To overcome free-carrier related performance degradations we have investigated reverse biased p-i-n structures, demonstrating an improvement in the pair generation rate by a factor of up to 2, with negligible impact on CAR.Comment: 5 pages, 3 figure