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1.
J Glob Health ; 14: 04136, 2024 Jun 28.
Article in English | MEDLINE | ID: mdl-38940275

ABSTRACT

Background: There is minimal data on the number of adolescents in sub-Saharan Africa (SSA) with elevated blood pressure (BP) at increased risk of future cardiovascular events. Combining country-specific population data with data derived from two previously conducted meta-analyses (one African-specific, one based on international cohorts), we sought to address this knowledge deficit. Methods: We used meta-analysis data from 37 926 adolescents participating in 36 contemporary SSA studies to generate sex-specific proportions of adolescents aged 10-14 and 15-19 years with elevated BP. The estimates were applied to the 2021 World Bank population data for each country in SSA. We then applied the rate of cardiovascular events attributable to elevated BP levels, derived from a meta-analysis of 17 observational, longitudinal cohort studies comprising 4.5 million young adults (non-African), to determine the excess number of cardiovascular events linked to hypertension among those aged 15-19 years transitioning to adulthood. Results: The estimated prevalence of elevated BP among male and female adolescents aged 10-14 years living in SSA was 7.2% (95% confidence interval (CI) = 4.9-9.9) and 6.9% (95% CI = 4.7-9.5), respectively, which increased to 13.0% (95% CI = 10.6-15.6) and 12.5% (95% CI = 10.4-15.3) among male and female adolescents aged 15-19 years, respectively. Consequently, we estimate that 13.6/138.0 million (95% CI = 10.4-17.3) male and 12.9/135.7 million (95% CI = 9.83-16.3) female adolescents living in SSA have elevated BP. Among the estimated 16.1 million adolescents aged 15-19 years with elevated BP approaching adulthood, the projected excess in cardiovascular events attributable to hypertension (vs normotension) is 201 000 (95% CI = 115 000-322 000) to 503 000 (95% CI = 286 000-805 000) over the next 10-25 years. Conclusions: Based on the best available data, we estimate that 26.5 million adolescents living in SSA have elevated BP. If left undetected and untreated among those approaching adulthood (those aged 15-19 years), they will experience >0.5 million excess cardiovascular events associated with persistently elevated BP within the next 25 years. Registration: PROSPERO: CRD42022297948.


Subject(s)
Hypertension , Humans , Adolescent , Africa South of the Sahara/epidemiology , Hypertension/epidemiology , Male , Female , Child , Young Adult , Prevalence , Cardiovascular Diseases/epidemiology , Cost of Illness
2.
Sci Robot ; 9(91): eadk3925, 2024 Jun 12.
Article in English | MEDLINE | ID: mdl-38865475

ABSTRACT

Electrotactile stimulus is a form of sensory substitution in which an electrical signal is perceived as a mechanical sensation. The electrotactile effect could, in principle, recapitulate a range of tactile experience by selective activation of nerve endings. However, the method has been plagued by inconsistency, galvanic reactions, pain and desensitization, and unwanted stimulation of nontactile nerves. Here, we describe how a soft conductive block copolymer, a stretchable layout, and concentric electrodes, along with psychophysical thresholding, can circumvent these shortcomings. These purpose-designed materials, device layouts, and calibration techniques make it possible to generate accurate and reproducible sensations across a cohort of 10 human participants and to do so at ultralow currents (≥6 microamperes) without pain or desensitization. This material, form factor, and psychophysical approach could be useful for haptic devices and as a tool for activation of the peripheral nervous system.


Subject(s)
Elastomers , Electric Conductivity , Psychophysics , Touch , Humans , Touch/physiology , Adult , Female , Male , Equipment Design , Electric Stimulation , Young Adult , Polymers , Electrodes , Calibration , Touch Perception/physiology
3.
Appl Opt ; 63(12): 3359-3365, 2024 Apr 20.
Article in English | MEDLINE | ID: mdl-38856488

ABSTRACT

Single-line-defect (W1) photonic crystal waveguides hold significant promise for various applications in integrated photonics due to their ability to induce slow light across wide photonic band ranges. Ensuring the manufacturing reliability of these devices is paramount for their practical implementation, as they tend to be highly sensitive to fabrication deviations. In this study, we investigated the manufacturing reliability of photonic crystal waveguides fabricated at the Albany Nanotech Complex foundry by comparing the consistency of band-edge locations and group indices across 14 chips. We also provide FIB images of the fabricated photonic crystals allowing an analysis of the sidewall quality of the holes.

4.
Ann Hepatol ; 29(4): 101510, 2024.
Article in English | MEDLINE | ID: mdl-38714224

ABSTRACT

INTRODUCTION AND OBJECTIVES: Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease worldwide and can progress to non-alcoholic steatohepatitis (NASH) and, ultimately, cirrhosis. Clostridioides difficile is the most common nosocomial cause of diarrhea and is associated with worse clinical outcomes in other liver diseases, including cirrhosis, but has not been extensively evaluated in concomitant NAFLD/NASH. MATERIALS AND METHODS: We conducted a retrospective cohort study using the National Inpatient Sample database from 2015 to 2017. Patients with a diagnosis of CDI, NAFLD, and NASH were identified using International Classification of Diseases (Tenth Revision) codes. The outcomes of our study include length of stay, hospitalization cost, mortality, and predictors of mortality. RESULTS: The CDI and NASH cohort had a higher degree of comorbidity burden and prevalence of peptic ulcer disease, congestive heart failure, diabetes mellitus, and cirrhosis. Patients with NASH and CDI had a significantly higher mortality rate compared to the CDI only cohort (mortality, 7.11 % vs. 6.36 %; P = 0.042). Patients with CDI and NASH were at increased risk for liver-related complications, acute kidney injury, and septic shock (P < 0.001) compared to patients with CDI only. Older age, intestinal complications, pneumonia, sepsis and septic shock, and liver failure conferred an increased risk of mortality among the CDI and NASH cohort. CONCLUSIONS: Patients with NASH had a higher rate of liver-related complications, progression to septic shock, and mortality rate following CDI infection compared to the CDI only cohort.


Subject(s)
Clostridium Infections , Non-alcoholic Fatty Liver Disease , Humans , Non-alcoholic Fatty Liver Disease/mortality , Non-alcoholic Fatty Liver Disease/epidemiology , Non-alcoholic Fatty Liver Disease/complications , Male , Female , Retrospective Studies , Risk Factors , Middle Aged , Clostridium Infections/mortality , Clostridium Infections/epidemiology , Clostridium Infections/diagnosis , Aged , Clostridioides difficile , United States/epidemiology , Databases, Factual , Length of Stay/statistics & numerical data , Adult , Comorbidity , Hospital Costs , Risk Assessment
5.
JACC Basic Transl Sci ; 9(3): 322-338, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38559631

ABSTRACT

This study evaluates the effectiveness of myocardial matrix (MM) hydrogels in mitigating negative right ventricular (RV) remodeling in a rat model of RV heart failure. The goal was to assess whether a hydrogel derived from either the right or left ventricle could promote cardiac repair. Injured rat right ventricles were injected with either RV-or left ventricular-derived MM hydrogels. Both hydrogels improved RV function and morphology and reduced negative remodeling. This study supports the potential of injectable biomaterial therapies for treating RV heart failure.

6.
Access Microbiol ; 6(2)2024.
Article in English | MEDLINE | ID: mdl-38482357

ABSTRACT

Severe acute respiratory syndrome (SARS) coronavirus 2 (SARS-CoV-2) is a novel human coronavirus that was identified in 2019. SARS-CoV-2 infection results in an acute, severe respiratory disease called coronavirus disease 2019 (COVID-19). The emergence and rapid spread of SARS-CoV-2 has led to a global public health crisis, which continues to affect populations across the globe. Real time reverse transcription polymerase chain reaction (rRT-PCR) is the reference standard test for COVID-19 diagnosis. Serological tests are valuable tools for serosurveillance programs and establishing correlates of protection from disease. This study evaluated the performance of one in-house enzyme linked immunosorbent assay (ELISA) utilizing the pre-fusion stabilized ectodomain of SARS-CoV-2 spike (S), two commercially available chemiluminescence assays Ortho VITROS Immunodiagnostic Products Anti-SARS-CoV-2 Total Reagent Pack and Abbott SARS-CoV-2 IgG assay and one commercially available Surrogate Virus Neutralization Test (sVNT), GenScript USA Inc., cPass SARS-CoV-2 Neutralization Antibody Detection Kit for the detection of SARS-CoV-2 specific antibodies. Using a panel of rRT-PCR confirmed COVID-19 patients' sera and a negative control group as a reference standard, all three immunoassays demonstrated high comparable positivity rates and low discordant rates. All three immunoassays were highly sensitive with estimated sensitivities ranging from 95.4-96.6 %. ROC curve analysis indicated that all three immunoassays had high diagnostic accuracies with area under the curve (AUC) values ranging from 0.9698 to 0.9807. High positive correlation was demonstrated among the conventional microneutralization test (MNT) titers and the sVNT inhibition percent values. Our study indicates that independent evaluations are necessary to optimize the overall utility and the interpretation of the results of serological tests. Overall, we demonstrate that all serological tests evaluated in this study are suitable for the detection of SARS-CoV-2 antibodies.

7.
Chem Sci ; 15(12): 4510-4518, 2024 Mar 20.
Article in English | MEDLINE | ID: mdl-38516096

ABSTRACT

Superlattice formation afforded by metal halide perovskite nanocrystals has been a phenomenon of interest due to the high structural order induced in these self-assemblies, an order that is influenced by the surface chemistry and particle morphology of the starting building block material. In this work, we report on the formation of superlattices from aluminum oxide shelled CsPbBr3 perovskite nanocrystals where the oxide shell is grown by colloidal atomic layer deposition. We demonstrate that the structural stability of these superlattices is preserved over 25 days in an inert atmosphere and that colloidal atomic layer deposition on colloidal perovskite nanocrystals yields structural protection and an enhancement in photoluminescence quantum yields and radiative lifetimes as opposed to gas phase atomic layer deposition on pre-assembled superlattices or excess capping group addition. Structural analyses found that shelling resulted in smaller nanocrystals that form uniform supercrystals. These effects are in addition to the increasingly static capping group chemistry initiated where oleic acid is installed as a capping ligand directly on aluminum oxide. Together, these factors lead to fundamental observations that may influence future superlattice assembly design.

8.
Clin Liver Dis ; 28(2): 209-224, 2024 05.
Article in English | MEDLINE | ID: mdl-38548434

ABSTRACT

Hepatic encephalopathy (HE) is a neuropsychiatric syndrome that is observed primarily in patients with liver disease. The pathophysiology is complex and involves many factors including ammonia toxicity, dysregulation of central nervous system activity, and excess inflammatory cytokines. Symptoms of HE range from subclinical to debilitating. HE can be difficult to treat and represents a large burden to patients, their caregivers, and the health-care system because of associated resource utilization. This review article provides an overview of the current understanding of the pathophysiology behind HE and where the current research and treatments are pointing toward.


Subject(s)
Hepatic Encephalopathy , Humans , Hepatic Encephalopathy/etiology , Hepatic Encephalopathy/therapy , Hepatic Encephalopathy/diagnosis , Central Nervous System , Ammonia
9.
Cell Rep ; 43(4): 113971, 2024 Apr 23.
Article in English | MEDLINE | ID: mdl-38537644

ABSTRACT

Sorghum bicolor is among the most important cereals globally and a staple crop for smallholder farmers in sub-Saharan Africa. Approximately 20% of sorghum yield is lost annually in Africa due to infestation with the root parasitic weed Striga hermonthica. Existing Striga management strategies are not singularly effective and integrated approaches are needed. Here, we demonstrate the functional potential of the soil microbiome to suppress Striga infection in sorghum. We associate this suppression with microbiome-mediated induction of root endodermal suberization and aerenchyma formation and with depletion of haustorium-inducing factors, compounds required for the initial stages of Striga infection. We further identify specific bacterial taxa that trigger the observed Striga-suppressive traits. Collectively, our study describes the importance of the soil microbiome in the early stages of root infection by Striga and pinpoints mechanisms of Striga suppression. These findings open avenues to broaden the effectiveness of integrated Striga management practices.


Subject(s)
Microbiota , Plant Roots , Soil Microbiology , Sorghum , Striga , Sorghum/microbiology , Sorghum/metabolism , Striga/physiology , Plant Roots/microbiology , Plant Roots/metabolism , Plant Roots/parasitology , Metabolome , Plant Diseases/microbiology , Plant Diseases/parasitology
10.
Article in English | MEDLINE | ID: mdl-38442225

ABSTRACT

Background: Current rates of reported pediatric femoral hernias remain exceedingly low, with their incidence reported to be <1%. The mainstay of repair has traditionally been through an open approach, and pediatric surgeons remain reluctant to repair otherwise. Owing to its rarity, consensus regarding management remains absent. Because of this, we present a scoping review on the use of laparoscopy and minimally invasive techniques to repair pediatric femoral hernias. Methods: A scoping literature review was performed using PubMed, Embase, Scopus, and Web of Science for related articles (keywords). Full-text articles and abstracts were then reviewed for relevance using inclusion and exclusion criteria with data extracted from each piece. Results: The search identified 268 articles published from 1992 to 2023. Eleven articles met our inclusion criteria. After reviewing their content, a total of 87 patients were identified. Of these, 42 laparoscopic repairs were reported. Three primary laparoscopic surgical techniques were described, with no recurrence reported. Conclusion: Laparoscopy remains a viable tool in diagnosing and managing femoral hernias. Various technically feasible options for laparoscopy and minimally invasive techniques have been described with excellent results and limited recurrence. However, given the quality of the data, further studies are needed to investigate the long-term durability of such repairs.

11.
J Thorac Dis ; 16(1): 450-456, 2024 Jan 30.
Article in English | MEDLINE | ID: mdl-38410559

ABSTRACT

Background: Radial probe endobronchial ultrasound (R-EBUS) is often utilized in guided bronchoscopy for the diagnosis of peripheral pulmonary lesions. R-EBUS probe positioning has been shown to correlate with diagnostic yield, but overall diagnostic yield with this technology has been inconsistent across the published literature. Currently there is no standardization for R-EBUS image interpretation, which may result in variability in grading concentricity of lesions and subsequently procedure performance. This was a survey-based study evaluating variability among practicing pulmonologists in R-EBUS image interpretation. Methods: R-EBUS images from peripheral bronchoscopy cases were sent to 10 practicing Interventional Pulmonologists at two different time points (baseline and 3 months). Participants were asked to grade the images as concentric, eccentric, or no image. Cohen's Kappa-coefficient was calculated for inter- and intra-observer variability. Results: A total of 100 R-EBUS images were included in the survey. There was 100% participation with complete survey responses from all 10 participants. Overall kappa-statistic for inter-observer variability for Survey 1 and 2 was 0.496 and 0.477 respectively. Overall kappa-statistic for intra-observer variability between the two surveys was 0.803. Conclusions: There is significant variability between pulmonologists when characterizing R-EBUS images. However, there is strong intra-rater agreement from each participant between surveys. A standardized approach and grading system for radial EBUS patterns may improve inter-observer variability in order to optimize our clinical use and research efforts in the field.

13.
Perception ; 53(1): 17-30, 2024 Jan.
Article in English | MEDLINE | ID: mdl-37859336

ABSTRACT

Everyday experiences suggest that a container, such as a box of cereal, can convey pertinent information about the nature and quantity of its content. This study investigated how well people can judge large quantities of objects in a container through haptic perception. Stimuli consisted of plastic drinking straws cut to "small" (1.5 cm) or "big" (4.5 cm) pieces contained in plastic food containers. Participants performed both a magnitude estimation of the number of objects and a direct estimation of the proportion of the container perceived to be filled with objects. Overall, participants demonstrated considerable accuracy for both tasks and irrespective of the size of the content. Post-experiment interviews revealed three potential strategies. Participants either focused on the container's contents, the excess space in the container, or the perceived weight of the container (content).


Subject(s)
Touch Perception , Touch , Humans
14.
Arch Peru Cardiol Cir Cardiovasc ; 4(3): 118-121, 2023.
Article in English | MEDLINE | ID: mdl-38046232

ABSTRACT

Candida endocarditis is a severe disease associated with high mortality rates. Candida parapsilosis is frequently identified as the causative pathogen in intravenous drug users and is commonly associated with nosocomial infections, primarily due to its ability to form biofilms on catheters or other foreign bodies. Here, we present a rare case of Candida parapsilosis endocarditis affecting the native tricuspid valve in a 35-year-old male patient with end-stage chronic kidney disease (Stage V), who had a suspected fungal infection related to the left cervical catheter. The patient received treatment with caspofungin and underwent excision of a verrucous tumor on the tricuspid valve. Despite encountering postoperative complications, the patient was discharged on fluconazole treatment and scheduled for follow-up. Candida endocarditis poses a clinical challenge that necessitates a multidisciplinary approach and tailored management due to its infrequent occurrence and higher mortality rate compared to bacterial endocarditis.


La endocarditis por Candida es una enfermedad grave asociada con tasas de mortalidad elevadas. Candida parapsilosis se identifica con frecuencia como un patógeno que afecta usuarios de drogas intravenosas y está comúnmente relacionada con infecciones nosocomiales, principalmente debido a su capacidad para formar biopelículas en catéteres u otros cuerpos extraños. Se presenta un caso inusual de endocarditis por Candida parapsilosis que afecta la válvula tricúspide nativa en un paciente masculino de 35 años con enfermedad renal crónica en etapa terminal (Etapa V), quien tenía una sospecha de infección fúngica relacionada con el catéter cervical izquierdo. El paciente recibió tratamiento con caspofungina y se sometió a la extirpación de un tumor verrugoso en la válvula tricúspide. A pesar de enfrentar complicaciones posoperatorias, el paciente fue dado de alta con tratamiento de fluconazol y se programó un seguimiento. La endocarditis por Candida presenta un desafío clínico que requiere un enfoque multidisciplinario y un manejo personalizado debido a su ocurrencia infrecuente y una tasa de mortalidad más alta en comparación con la endocarditis bacteriana.

15.
Cureus ; 15(11): e49432, 2023 Nov.
Article in English | MEDLINE | ID: mdl-38152812

ABSTRACT

BACKGROUND:  The incidence of colorectal cancer (CRC) in patients younger than 50 has been rising over the last several decades, accounting for up to 25% of total cases. Despite the screening age recently being lowered to 45, a significant proportion of cases would still arise at younger ages prior to screening. Nonfamilial early-onset CRC remains a particular concern. Identification of risk factors and clinical features in this age group is needed to improve detection. METHODS: In this retrospective cohort analysis using claims data from the Truven Health MarketScan® Commercial Claims insurance database from 2007 to 2017, patients were identified with colon and rectal cancer, compared across three age groups (ages 18-40, 40-50, and >50), and analyzed for risk factors and clinical features. RESULTS: Female sex was more prevalent in the younger age group compared to age >50 (54% and 51.9% vs. 49.6%), with little change noted between rectal cancer age groups by sex. A higher percentage of younger patients were in the obese age groups compared with older groups for colon cancer, particularly the morbidly obese with BMI >40 (24.94%, 25.75%, and 21.34% in the three age groups). Abdominal pain was a common presenting symptom identified in the age groups <50 compared with age >50 (25% and 19% vs. 14%), along with hematochezia, weight loss, and anemia. CONCLUSIONS: Morbid obesity and female sex may be important risk factors among patients with early-onset CRC. The presence of abdominal pain was more common among the early-onset CRC cohort.

16.
World J Hepatol ; 15(10): 1164-1169, 2023 Oct 27.
Article in English | MEDLINE | ID: mdl-37970616

ABSTRACT

BACKGROUND: Inflammatory pseudotumor (IPT) is a rare and benign lesion that mimics malignancy and can develop in any part of the body. The pathophysiology and etiology of these quasineoplastic lesions remain unclear. CASE SUMMARY: We report a case of a 65-year-old male who presented with fevers, night sweats, and unintentional weight loss following an influenza infection and was found to have multiple hepatic IPT's following an extensive work up. CONCLUSION: Our case highlights the importance of considering hepatic IPT's in the differential in a patient who presents with symptoms and imaging findings mimicking malignancy shortly following a viral infection.

17.
J Am Chem Soc ; 145(46): 25401-25410, 2023 Nov 22.
Article in English | MEDLINE | ID: mdl-37948677

ABSTRACT

Nanosized particles of liquid metals are emerging materials that hold promise for applications spanning from microelectronics to catalysis. Yet, knowledge of their chemical reactivity is largely unknown. Here, we study the reactivity of liquid Ga and Cu nanoparticles under the application of a cathodic voltage. We discover that the applied voltage and the spatial proximity of these two particle precursors dictate the reaction outcome. In particular, we find that a gradual voltage ramp is crucial to reduce the native oxide skin of gallium and enable reactive wetting between the Ga and Cu nanoparticles; instead, a voltage step causes dewetting between the two. We determine that the use of liquid Ga/Cu nanodimer precursors, which consist of an oxide-covered Ga domain interfaced with a metallic Cu domain, provides a more uniform mixing and results in more homogeneous reaction products compared to a physical mixture of Ga and Cu NPs. Having learned this, we obtain CuGa2 alloys or solid@liquid CuGa2@Ga core@shell nanoparticles by tuning the stoichiometry of Ga and Cu in the nanodimer precursors. These products reveal an interesting complementarity of thermal and voltage-driven syntheses to expand the compositional range of bimetallic NPs. Finally, we extend the voltage-driven synthesis to the combination of Ga with other elements (Ag, Sn, Co, and W). By rationalizing the impact of the native skin reduction rate, the wetting properties, and the chemical reactivity between Ga and other metals on the results of such voltage-driven chemical manipulation, we define the criteria to predict the outcome of this reaction and set the ground for future studies targeting various applications for multielement nanomaterials based on liquid Ga.

18.
Cureus ; 15(9): e44714, 2023 Sep.
Article in English | MEDLINE | ID: mdl-37809179

ABSTRACT

Background and objective Wilson's disease (WD) is a rare autosomal recessive disease caused by mutations in the ATP7B gene, leading to impairment in copper excretion and subsequent accumulation primarily in the liver and brain. There is scarce data in the literature on the outcomes and cost burden of WD. In light of this, we aimed to assess outcomes, mortality rates, and costs associated with WD patients and their management in the United States (US). Methods We conducted a retrospective cohort study based on data in the National Inpatient Sample (NIS) database from 2007 to 2017. A total of 17,713 patients with a diagnosis of WD were identified using the International Classification of Diseases, Ninth or Tenth Revision (ICD-9/10) codes. Bivariate analyses were performed using t-tests for continuous variables and Pearson's chi-square tests for categorical variables, where two-sided p-values <0.05 were considered statistically significant. Results The majority of the 17,713 identified patients were female. The mean age of the WD cohort was 49 years. WD patients had a higher prevalence of Kayser-Fleischer rings, neuropsychiatric symptoms, and liver-related complications including acute hepatitis, liver failure, portal hypertension, and cirrhosis. Peptic ulcer disease, connective tissue disease, and hemolytic anemia were significantly more common in the WD cohort. Compared to the non-WD cohort, the WD cohort had a significantly higher mortality rate, longer length of stay (LOS), and increased hospitalization costs (p<0.0001). A higher proportion of patients who had undergone orthotopic liver transplantation (OLTx) were in the 18-34 and 35-44-year-old subgroups. On the contrary, the highest proportion of patients with WD who had not undergone OLTx were in the 55-89-year-old subgroup. WD patients who had undergone OLTx had a lower degree of comorbidities, decreased mortality rate, and shorter LOS (all p<0.0001) compared to WD patients who had not undergone OLTx. Conclusion Based on our findings, patients with WD had a higher LOS, mean hospitalization costs, and mortality rate compared to the non-WD cohort. Mortality rate and LOS were significantly lower in WD patients who had undergone OLTx.

19.
SSM Popul Health ; 24: 101511, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37711359

ABSTRACT

Stakeholders need data on health and drivers of health parsed to the boundaries of essential policy-relevant geographies. US Congressional Districts are an example of a policy-relevant geography which generally lack health data. One strategy to generate Congressional District heath data metric estimates is to aggregate estimates from other geographies, for example, from counties or census tracts to Congressional Districts. Doing so requires several methodological decisions. We refine a method to aggregate health metric estimates from one geography to another, using a population weighted approach. The method's accuracy is evaluated by comparing three aggregated metric estimates to metric estimates from the US Census American Community Survey for the same years: Broadband Access, High School Completion, and Unemployment. We then conducted four sensitivity analyses testing: the effect of aggregating counts vs. percentages; impacts of component geography size and data missingness; and extent of population overlap between component and target geographies. Aggregated estimates were very similar to estimates for identical metrics drawn directly from the data source. Sensitivity analyses suggest the following best practices for Congressional district-based metrics: utilizing smaller, more plentiful geographies like census tracts as opposed to larger, less plentiful geographies like counties, despite potential for less stable estimates in smaller geographies; favoring geographies with higher percentage population overlap.

20.
Phys Rev Lett ; 131(11): 111004, 2023 Sep 15.
Article in English | MEDLINE | ID: mdl-37774289

ABSTRACT

Axions can be copiously produced in localized regions of neutron star magnetospheres where the ambient plasma is unable to efficiently screen the induced electric field. As these axions stream away from the neutron star they can resonantly transition into photons, generating a large broadband contribution to the neutron star's intrinsic radio flux. In this Letter, we develop a comprehensive end-to-end framework to model this process from the initial production of axions to the final detection of radio photons, and derive constraints on the axion-photon coupling, g_{aγγ}, using observations of 27 nearby pulsars. We study the modeling uncertainty in the sourced axion spectrum by comparing predictions from 2.5 dimensional particle-in-cell simulations with those derived using a semianalytic model; these results show remarkable agreement, leading to constraints on the axion-photon coupling that typically differ by a factor of no more than ∼2. The limits presented here are the strongest to date for axion masses 10^{-8} eV≲m_{a}≲10^{-5} eV, and crucially do not rely on the assumption that axions are dark matter.

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