Tripled yield in direct-drive laser fusion through statistical modelling.

Focusing laser light onto a very small target can produce the conditions for laboratory-scale nuclear fusion of hydrogen isotopes. The lack of accurate predictive models, which are essential for the design of high-performance laser-fusion experiments, is a major obstacle to achieving thermonuclear ignition. Here we report a statistical approach that was used to design and quantitatively predict the results of implosions of solid deuterium-tritium targets carried out with the 30-kilojoule OMEGA laser system, leading to tripling of the fusion yield to its highest value so far for direct-drive laser fusion. When scaled to the laser energies of the National Ignition Facility (1.9 megajoules), these targets are predicted to produce a fusion energy output of about 500 kilojoules-several times larger than the fusion yields currently achieved at that facility. This approach could guide the exploration of the vast parameter space of thermonuclear ignition conditions and enhance our understanding of laser-fusion physics.

Effect of Strongly Magnetized Electrons and Ions on Heat Flow and Symmetry of Inertial Fusion Implosions.

This Letter presents the first observation on how a strong, 500 kG, externally applied B field increases the mode-two asymmetry in shock-heated inertial fusion implosions. Using a direct-drive implosion with polar illumination and imposed field, we observed that magnetization produces a significant increase in the implosion oblateness (a 2.5× larger P2 amplitude in x-ray self-emission images) compared with reference experiments with identical drive but with no field applied. The implosions produce strongly magnetized electrons (ω_{e}τ_{e}≫1) and ions (ω_{i}τ_{i}>1) that, as shown using simulations, restrict the cross field heat flow necessary for lateral distribution of the laser and shock heating from the implosion pole to the waist, causing the enhanced mode-two shape.

Direct Measurements of DT Fuel Preheat from Hot Electrons in Direct-Drive Inertial Confinement Fusion.

Hot electrons generated by laser-plasma instabilities degrade the performance of laser-fusion implosions by preheating the DT fuel and reducing core compression. The hot-electron energy deposition in the DT fuel has been directly measured for the first time by comparing the hard x-ray signals between DT-layered and mass-equivalent ablator-only implosions. The electron energy deposition profile in the fuel is inferred through dedicated experiments using Cu-doped payloads of varying thickness. The measured preheat energy accurately explains the areal-density degradation observed in many OMEGA implosions. This technique can be used to assess the viability of the direct-drive approach to laser fusion with respect to the scaling of hot-electron preheat with laser energy.

Fast electron transport dynamics and energy deposition in magnetized, imploded cylindrical plasma.

Inertial confinement fusion approaches involve the creation of high-energy-density states through compression. High gain scenarios may be enabled by the beneficial heating from fast electrons produced with an intense laser and by energy containment with a high-strength magnetic field. Here, we report experimental measurements from a configuration integrating a magnetized, imploded cylindrical plasma and intense laser-driven electrons as well as multi-stage simulations that show fast electrons transport pathways at different times during the implosion and quantify their energy deposition contribution. The experiment consisted of a CH foam cylinder, inside an external coaxial magnetic field of 5 T, that was imploded using 36 OMEGA laser beams. Two-dimensional (2D) hydrodynamic modelling predicts the CH density reaches [Formula: see text], the temperature reaches 920 eV and the external B-field is amplified at maximum compression to 580 T. At pre-determined times during the compression, the intense OMEGA EP laser irradiated one end of the cylinder to accelerate relativistic electrons into the dense imploded plasma providing additional heating. The relativistic electron beam generation was simulated using a 2D particle-in-cell (PIC) code. Finally, three-dimensional hybrid-PIC simulations calculated the electron propagation and energy deposition inside the target and revealed the roles the compressed and self-generated B-fields play in transport. During a time window before the maximum compression time, the self-generated B-field on the compression front confines the injected electrons inside the target, increasing the temperature through Joule heating. For a stronger B-field seed of 20 T, the electrons are predicted to be guided into the compressed target and provide additional collisional heating. This article is part of a discussion meeting issue 'Prospects for high gain inertial fusion energy (part 2)'.

Lipoatrophic panniculitis in an adolescent.

Lipoatrophic panniculitis (LP) is a rare childhood panniculitis characterized by sclerotic, atrophic plaques on the extremities. We present a case of LP diagnosed during the inflammatory phase that was difficult to distinguish clinically from eosinophilic fasciitis. This report adds to the limited phenotypic spectrum of LP by differentiating the clinical features of disease activity from disease damage and highlighting the importance of biopsy in establishing a diagnosis.

Clinical, Imaging, and Pathologic Features of Conditions with Combined Esophageal and Cutaneous Manifestations.

A variety of clinically significant conditions can affect both the esophagus and the skin. Esophageal and cutaneous manifestations may directly reflect the underlying disease process, as in infections such as herpes simplex virus, bullous diseases such as epidermolysis bullosa and mucous membrane pemphigoid, connective tissue diseases such as systemic sclerosis, and inflammatory diseases such as lichen planus. Alternatively, esophageal and cutaneous findings may result from conditions that are closely associated with and potentially pathognomonic for but distinct from the underlying disease process, as in genetic diseases such as Cowden syndrome or paraneoplastic syndromes such as acrokeratosis paraneoplastica. Other diseases such as Crohn disease may have cutaneous manifestations that directly reflect the same underlying inflammatory process that affects the gastrointestinal tract or cutaneous manifestations that represent reactive or associated conditions distinct from the underlying inflammatory process. The cutaneous manifestations of disease may precede, coincide with, or follow the esophageal manifestations of disease. The authors present the characteristic clinical features and imaging findings associated with common and uncommon conditions that have esophageal and cutaneous manifestations. Each condition is presented with a brief overview, discussion of salient clinical and cutaneous manifestations, and description of the typical esophageal imaging findings, with particular attention to implications for diagnosis, prognosis, and treatment. Recognition of potential associations between cutaneous lesions and esophageal imaging findings is important for establishing a specific diagnosis or generating a meaningful differential diagnosis.

Gigabar spherical shock generation on the OMEGA laser.

This Letter presents the first experimental demonstration of the capability to launch shocks of several-hundred Mbar in spherical targets--a milestone for shock ignition [R. Betti et al., Phys. Rev. Lett. 98, 155001 (2007)]. Using the temporal delay between the launching of the strong shock at the outer surface of the spherical target and the time when the shock converges at the center, the shock-launching pressure can be inferred using radiation-hydrodynamic simulations. Peak ablation pressures exceeding 300 Mbar are inferred at absorbed laser intensities of ∼3×10(15) W/cm2. The shock strength is shown to be significantly enhanced by the coupling of suprathermal electrons with a total converted energy of up to 8% of the incident laser energy. At the end of the laser pulse, the shock pressure is estimated to exceed ∼1 Gbar because of convergence effects.

Enhanced relativistic-electron-beam energy loss in warm dense aluminum.

Energy loss in the transport of a beam of relativistic electrons in warm dense aluminum is measured in the regime of ultrahigh electron beam current density over 2×10^{11} A/cm^{2} (time averaged). The samples are heated by shock compression. Comparing to undriven cold solid targets, the roles of the different initial resistivity and of the transient resistivity (upon target heating during electron transport) are directly observable in the experimental data, and are reproduced by a comprehensive set of simulations describing the hydrodynamics of the shock compression and electron beam generation and transport. We measured a 19% increase in electron resistive energy loss in warm dense compared to cold solid samples of identical areal mass.

Faster scaling of auditory neurons in cortical areas relative to subcortical structures in primate brains.

Allometric studies in primates have shown that the cerebral cortex, cerebellum, and remaining brain structures increase in size as a linear function of their numbers of neurons and nonneuronal cells across primates. Whether such scaling rules also apply to functionally related structures such as those of the auditory system is unknown. Here, we investigate the scaling of brain structures in the auditory pathway of six primate species and the closely related tree shrew. Using the isotropic fractionator method to estimate the numbers of neurons and nonneuronal cells in the inferior colliculus, medial geniculate nucleus, and auditory cortex (Ac), we assessed how they scaled across species and examined the relative scaling relationships among them. As expected, each auditory structure scales in mass as a linear function of its number of neurons, with no significant changes in neuronal density across species. The Ac scales proportionately with the cerebral cortex as a whole, maintaining a relative mass of approximately 1% and a relative number of neurons of 0.7%. However, the Ac gains neurons faster than both subcortical structures examined. As a result, larger primate brains have increased ratios of cortical to subcortical neurons involved in processing auditory information.

Diversity and Career Goals of Graduating Allopathic Medical Students Pursuing Careers in Dermatology.

Importance: Dermatology is one of the least diverse specialties, while patients from minority racial and ethnic groups and other underserved populations continue to face numerous dermatology-specific health and health care access disparities in the US. Objectives: To examine the demographic characteristics and intended career goals of graduating US allopathic medical students pursuing careers in dermatology compared with those pursuing other specialties and whether these differ by sex, race and ethnicity, and/or sexual orientation. Design, Setting, and Participants: This secondary analysis of a repeated cross-sectional study included 58 077 graduating allopathic medical students using data from the 2016 to 2019 Association of American Medical Colleges Graduation Questionnaires. Main Outcomes and Measures: The proportion of female students, students from racial and ethnic groups underrepresented in medicine (URM), and sexual minority (SM) students pursuing dermatology vs pursuing other specialties. The proportions and multivariable-adjusted odds of intended career goals between students pursuing dermatology and those pursuing other specialties and by sex, race and ethnicity, and sexual orientation among students pursuing dermatology. Results: A total of 58 077 graduating students were included, with 28 489 (49.0%) female students, 8447 (14.5%) URM students, and 3641 (6.3%) SM students. Female students pursuing dermatology were less likely than female students pursuing other specialties to identify as URM (96 of 829 [11.6%] vs 4760 of 27 660 [17.2%]; P < .001) or SM (16 [1.9%] vs 1564 [5.7%]; P < .001). In multivariable-adjusted analyses, students pursuing dermatology compared with other specialties had decreased odds of intending to care for underserved populations (247 of 1350 [18.3%] vs 19 142 of 56 343 [34.0%]; adjusted odd ratio [aOR], 0.40; 95% CI, 0.35-0.47; P < .001), practice in underserved areas (172 [12.7%] vs 14 570 [25.9%]; aOR, 0.40; 95% CI, 0.34-0.47; P < .001), and practice public health (230 [17.0%] vs 17 028 [30.2%]; aOR, 0.44; 95% CI, 0.38-0.51; P < .001) but increased odds of pursuing research (874 [64.7%] vs 29 121 [51.7%]; aOR, 1.76; 95% CI, 1.57-1.97; P < .001) in their careers. Among students pursuing dermatology, female, URM, and SM identities were independently associated with increased odds of caring for underserved populations (eg, URM: aOR, 4.05; 95% CI, 2.83-5.80) and practicing public health (eg, SM: aOR, 2.55; 95% CI, 1.51-4.31). URM students compared with non-URM students pursuing dermatology had increased odds of intending to practice in underserved areas (aOR, 3.93; 95% CI, 2.66-5.80), and SM students compared with heterosexual students pursuing dermatology had increased odds of intending to become medical school faculty (aOR, 1.60; 95% CI, 1.01-2.57), to pursue administrative roles (aOR, 1.60; 95% CI, 1.01-2.59), and to conduct research (aOR, 1.73; 95% CI, 1.01-2.98). Conclusions and Relevance: The findings of this cross-sectional study suggest that diversity gaps continue to exist in the dermatology workforce pipeline. Efforts are needed to increase racial and ethnic and sexual orientation diversity and interest in careers focused on underserved care and public health among students pursuing dermatology.

Laser-direct-drive fusion target design with a high-Z gradient-density pusher shell.

Laser-direct-drive fusion target designs with solid deuterium-tritium (DT) fuel, a high-Z gradient-density pusher shell (GDPS), and a Au-coated foam layer have been investigated through both 1D and 2D radiation-hydrodynamic simulations. Compared with conventional low-Z ablators and DT-push-on-DT targets, these GDPS targets possess certain advantages of being instability-resistant implosions that can be high adiabat (α≥8) and low hot-spot and pusher-shell convergence (CR_{hs}≈22 and CR_{PS}≈17), and have a low implosion velocity (v_{imp}<3×10^{7}cm/s). Using symmetric drive with laser energies of 1.9 to 2.5MJ, 1D lilac simulations of these GDPS implosions can result in neutron yields corresponding to ≳50-MJ energy, even with reduced laser absorption due to the cross-beam energy transfer (CBET) effect. Two-dimensional draco simulations show that these GDPS targets can still ignite and deliver neutron yields from 4 to ∼10MJ even if CBET is present, while traditional DT-push-on-DT targets normally fail due to the CBET-induced reduction of ablation pressure. If CBET is mitigated, these GDPS targets are expected to produce neutron yields of >20MJ at a driven laser energy of ∼2MJ. The key factors behind the robust ignition and moderate energy gain of such GDPS implosions are as follows: (1) The high initial density of the high-Z pusher shell can be placed at a very high adiabat while the DT fuel is maintained at a relatively low-entropy state; therefore, such implosions can still provide enough compression ρR>1g/cm^{2} for sufficient confinement; (2) the high-Z layer significantly reduces heat-conduction loss from the hot spot since thermal conductivity scales as ∼1/Z; and (3) possible radiation trapping may offer an additional advantage for reducing energy loss from such high-Z targets.

Knowledge Retention and Clinical Skills Acquisition in Sexual and Gender Minority Health Curricula: A Systematic Review.

PURPOSE: To identify exemplary medical education curricula, operationalized as curricula evaluating knowledge retention and/or clinical skills acquisition, for health care for sexual and gender minoritized (SGM) individuals and individuals born with a difference in sex development (DSD). METHOD: The authors conducted a systematic review of the literature using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Searches were performed in PubMed/MEDLINE, The Cochrane Library, Web of Science, ERIC, Embase, PsycINFO, and the gray literature to identify studies that (1) pertained to undergraduate and/or graduate medical education, (2) addressed education on health care of SGM/DSD individuals, and (3) assessed knowledge retention and/or clinical skills acquisition in medical trainees. The final searches were run in March 2019 and rerun before final analyses in June and October 2020. RESULTS: Of 670 full-text articles reviewed, 7 met the inclusion criteria. Five of the 7 studies assessed trainee knowledge retention alone, 1 evaluated clinical skills acquisition alone, and 1 evaluated both outcomes. Studies covered education relevant to transgender health, endocrinology for patients born with DSDs, and HIV primary care. Only 1 study fully mapped to the Association of American Medical Colleges (AAMC) SGM/DSD competency recommendations. Six studies reported institutional funding and development support. No studies described teaching SGM/DSD health care for individuals with multiply minoritized identities or engaging the broader SGM/DSD community in medical education curriculum development and implementation. CONCLUSIONS: Curriculum development in SGM/DSD health care should target knowledge retention and clinical skills acquisition in line with AAMC competency recommendations. Knowledge and skill sets for responsible and equitable care are those that account for structures of power and oppression and cocreate curricula with people who are SGM and/or born with DSDs.

Demonstration of plasma mirror capability for the OMEGA Extended Performance laser system.

A plasma mirror platform was developed for the OMEGA-EP facility to redirect beams, thus enabling more flexible experimental configurations as well as a platform that can be used in the future to improve laser contrast. The plasma mirror reflected a short pulse focusing beam at 22.5° angle of incidence onto a 12.5 µm thick Cu foil, generating Bremsstrahlung and kα x rays, and accelerating ions and relativistic electrons. By measuring these secondary sources, the plasma mirror key performance metrics of integrated reflectivity and optical quality are inferred. It is shown that for a 5 ± 2 ps, 310 J laser pulse, the plasma mirror integrated reflectivity was 62 ± 13% at an operating fluence of 1670 J cm-2, and that the resultant short pulse driven particle acceleration and x-ray generation indicate that the on target intensity was 3.1 × 1018 W cm-2, which is indicative of a good post-plasma mirror interaction beam optical quality. By deriving the plasma mirror performance metrics from the secondary source scalings, it was simultaneously demonstrated that the plasma mirror is ready for adoption in short pulse particle acceleration and high energy photon generation experiments using the OMEGA-EP system.

Incidence and Factors Associated With Acne Among Transgender Patients Receiving Masculinizing Hormone Therapy.

Importance: Acne is a common condition among transgender patients receiving masculinizing hormone therapy (MHT), but the incident risk and predictors of developing acne in this population have not yet been studied on a large scale. Objective: To assess risk of acne among a large population of transgender patients receiving MHT and clinical risk factors for acne diagnosis. Design, Setting, and Participants: A retrospective cohort study that included 988 patients who started MHT between January 1, 2014, and December 31, 2017, with at least 1 year of follow-up was performed. Data analysis was conducted from September 1 to 15, 2019. Data were obtained using electronic health records from a community health center serving the sexual and gender minority community. The population included every patient who began receiving MHT during the study period who was aged 18 years or older at the time of MHT initiation and whose assigned sex at birth was female. Main Outcomes and Measures: The main outcome was acne defined by International Statistical Classification of Diseases, Tenth Revision, Clinical Modification codes for acne. Overall prevalence and incidence proportions over 2 years after initiation of MHT were calculated. Baseline demographic and clinical characteristics were collected at the time of MHT initiation. A series of univariate analyses for all factors was calculated to test for an association with acne diagnosis, followed by multivariate analyses to test for independent predictors. Results: For 988 patients (median age, 25.8 years; interquartile range, 20.8-28.2 years), there was an overall acne prevalence of 31.1% (n = 307). The 1-year post-MHT acne incidence proportion was 19.0% and the 2-year incidence proportion was 25.1%. A younger age at MHT initiation was associated with a higher likelihood of developing acne, with a median of 22.4 years (interquartile range, 19.7-25.6 years) among patients who developed acne vs 24.7 years (interquartile range, 21.3-29.4 years) among patients who did not (P = .002). Conclusions and Relevance: Acne is a common condition among transgender patients on MHT, with a prevalence increasing from 6.3% to 31.1% following MHT initiation. Patients aged 18 to 21 years appear to be the most likely to develop acne after MHT initiation.

Cellular scaling rules for primate spinal cords.

The spinal cord can be considered a major sensorimotor interface between the body and the brain. How does the spinal cord scale with body and brain mass, and how are its numbers of neurons related to the number of neurons in the brain across species of different body and brain sizes? Here we determine the cellular composition of the spinal cord in eight primate species and find that its number of neurons varies as a linear function of cord length, and accompanies body mass raised to an exponent close to 1/3. This relationship suggests that the extension, mass and number of neurons that compose the spinal cord are related to body length, rather than to body mass or surface. Moreover, we show that although brain mass increases linearly with cord mass, the number of neurons in the brain increases with the number of neurons in the spinal cord raised to the power of 1.7. This faster addition of neurons to the brain than to the spinal cord is consistent with current views on how larger brains add complexity to the processing of environmental and somatic information.

Health Insurance Coverage of Permanent Hair Removal in Transgender and Gender-Minority Patients.

Importance: Hair removal can be an essential component of the gender affirmation process for gender-minority (GM) patients whose outward appearance does not align with their gender identity. Objective: To examine the health insurance policies in the Affordable Care Act (ACA) marketplace and Medicaid policies for coverage of permanent hair removal for transgender and GM patients and to correlate the policies in each state with statewide protections of coverage for gender-affirming care. Design and Setting: Private health insurance policies available on the ACA marketplace and statewide Medicaid policies were examined in a cross-sectional study from September 1 to October 31, 2019, and January 17 to 30, 2020. Policies were assessed for coverage of permanent hair removal. Language concerning hair removal was found in each policy's medical or clinical coverage guidelines and separated into general categories. Main Outcomes and Measures: Logistic regression analyses were performed to compare Medicaid policies and ACA policies in states with and without transgender protections. Results: A total of 174 policies were analyzed, including 123 private insurance policies and 51 statewide Medicaid policies. Of these policies, 8 (4.6%) permitted the coverage of permanent hair removal without explicit restrictions. The remaining 166 policies (95.4%) broadly excluded or did not mention gender-affirming care; prohibited coverage of hair removal or did not mention it; or only permitted coverage of hair removal preoperatively for genital surgery. The ACA marketplace policies in states without transgender care protections were less likely to cover hair removal without restrictions than ACA policies in states with protections (2 of 85 policies [2.4%] in states without transgender care protections vs 5 of 38 policies [13.2%] in states with transgender care protections), and Medicaid policies were less likely to cover preoperative or nonsurgical hair removal compared with ACA policies (6 of 51 Medicaid policies [11.8%] vs 47 of 123 ACA policies [38.2%]). Conclusions and Relevance: Despite adoption of statewide restrictions on GM health care exclusions by several states, most Medicaid and ACA policies examined in this study did not cover permanent hair removal for transgender patients. Many GM patients seeking hair removal may be required to pay out-of-pocket costs, which could be a barrier for gender-affirming care.

Vaccine-Strain Herpes Zoster Ophthalmicus in a 14-month-old Boy Prompting an Immunodeficiency Workup: Case Report and Review of Vaccine-strain Herpes Zoster.

We present a case of herpes zoster ophthalmicus in an otherwise healthy 14-month-old male associated with vaccine-strain varicella-zoster virus 11 weeks after monovalent varicella vaccine administration. Herpes zoster ophthalmicus, especially in the setting of familial immunoglobulin A deficiency, prompted further immunologic workup. A high index of suspicion is necessary for timely diagnosis and treatment of vaccine-strain herpes zoster.