Dispersion Measurements Research Articles

Fast as Potoroo: Radio continuum detection of a bow-shock pulsar wind nebula powered by pulsar J1638–4713

Abstract We report the discovery of a bow-shock pulsar wind nebula (PWN), named Potoroo, and the detection of a young pulsar J1638 $-$ 4713 that powers the nebula. We present a radio continuum study of the PWN based on 20-cm observations obtained from the Australian Square Kilometre Array Pathfinder (ASKAP) and MeerKAT. PSR J1638 $-$ 4713 was identified using Parkes radio telescope observations at frequencies above 3 GHz. The pulsar has the second-highest dispersion measure of all known radio pulsars (1 553 pc cm $^{-3}$ ), a spin period of 65.74 ms and a spin-down luminosity of $\dot{E}=6.1\times10^{36}$ erg s $^{-1}$ . The PWN has a cometary morphology and one of the greatest projected lengths among all the observed pulsar radio tails, measuring over 21 pc for an assumed distance of 10 kpc. The remarkably long tail and atypically steep radio spectral index are attributed to the interplay of a supernova reverse shock and the PWN. The originating supernova remnant is not known so far. We estimated the pulsar kick velocity to be in the range of 1 000–2 000 km s $^{-1}$ for ages between 23 and 10 kyr. The X-ray counterpart found in Chandra data, CXOU J163802.6 $-$ 471358, shows the same tail morphology as the radio source but is shorter by a factor of 10. The peak of the X-ray emission is offset from the peak of the radio total intensity (Stokes $\rm I$ ) emission by approximately 4.7 $^{\prime\prime}$ , but coincides well with circularly polarised (Stokes $\rm V$ ) emission. No infrared counterpart was found.

Color tunable luminescence in ThO2:Er3+,Yb3+ nanocrystals: a promising new platform for upconversion.

Lanthanide-doped luminescent nanoparticles are an appealing system for many applications in the area of biomedical, solar cell, thermometry, anti-counterfeiting, etc. due to their sensitivity, reliability, high photochemical stability, and high optical transparency in the visible-NIR range. A color-tunable upconversion-luminescence (UCL) in a new low phonon energy ThO2 host based on modulating sensitizer concentration has been realized in this work and it may work as a potential candidate to replace corrosive and toxic fluoride based hosts in the future. Er3+-Yb3+ co-doped thoria nanoparticles were prepared using a gel combustion route and their structural and luminescence properties were determined as a function of the Yb3+ concentration. Phonon dispersion measurements have established the dynamic structural stability of the thoria nanoparticles. Density functional theory (DFT) was used to calculate the defect formation energy, highlighting the feasibility of dual ion (Er3+ and Yb3+) doping in thoria. The morphology and average size of the doped thoria was studied using high resolution transmission electron microscopy (HRTEM), and any defects evolving as a result of aliovalent doping were probed using positron annihilation lifetime spectroscopy (PALS). With 980 nm laser excitation, the nanothoria emits green and near-red light. A significant enhancement of the red-to-green intensity ratio of Er3+ ions in nanothoria was observed with an increase in Yb3+ concentration which resulted in beautiful color tunability from green to yellow light in going from lower (up to ∼5 mol%) to higher (10 and 15 mol%) Yb3+ concentration. The power dependence and the dynamics of the upconverted emission confirm the existence of two-photon upconversion processes for the green and red emissions.

Africa's Crustal Architecture Inferred From Probabilistic and Perturbational Inversion of Ambient Noise: ADAMA

AbstractAfrica's continental crust hosts a variety of geologic terrains and is crucial for understanding the evolution of its longest‐lived cratons. However, few of its seismological models are yet to incorporate the largest continent‐wide noise dispersion data sets. Here, we report on new insights into Africa's crustal architecture obtained using a new data set and model assessment product, ADAMA, which comprises a large ensemble of short‐period surface wave dispersion measurements: 5–40 s. We construct a continent‐wide model of Africa's Crust Evaluated with ADAMA's Rayleigh Phase maps (ACE‐ADAMA‐RP). Dispersion maps, and uncertainties, are obtained with a probabilistic approach. This model update, and a crustal taxonomy derived from unsupervised machine learning, reveals that the architecture of Africa's crust can be classified into two main types: primitive (C1: faster velocities with little gradients) and modified (C2–C4: slower velocities in the shallow crust with more pronounced gradients). The Archean shields are “primitive,” showing little variation or secular evolution. The basins, orogens, and continental margins are “modified” and retain imprints of surface deformation. The crustal taxonomy is obtained without a‐priori geological information and differs from previous classification schemes. While most of our reported features are robust, probabilistic modeling suggests caution in the quantitative interpretations where illumination is compromised by low‐quality measurements, sparse coverage or both. Future extension of our approach to other complementary seismological and geophysical data sets—for example, multimode earthquake dispersion, receiver functions, gravity, and mineral physics, will enable continent‐wide lithospheric modeling that extends resolution to the upper mantle.

Direct observation of split-mode exciton-polaritons in a single MoS2 nanotube.

A single nanotube synthesized from a transition metal dichalcogenide (TMDC) exhibits strong exciton resonances and, in addition, can support optical whispering gallery modes. This combination is promising for observing exciton-polaritons without an external cavity. However, traditional energy-momentum-resolved detection methods are unsuitable for this tiny object. Instead, we propose to use split optical modes in a twisted nanotube with the flattened cross-section, where a gradually decreasing gap between the opposite walls leads to a change in mode energy, similar to the effect of the barrier width on the eigenenergies in the double-well potential. Using micro-reflectance spectroscopy, we investigated the rich pattern of polariton branches in single MoS2 tubes with both variable and constant gaps. Observed Rabi splitting in the 40-60 meV range is comparable to that for a MoS2 monolayer in a microcavity. Our results, based on the polariton dispersion measurements and polariton dynamics analysis, present a single TMDC nanotube as a perfect polaritonic structure for nanophotonics.

Prevalence of Diabetes, Hypertension and Obesity among Doctors and Nurses in Universal College of Medical Sciences, Bhairahawa, Nepal

INTRODUCTION Hypertension (HTN) and diabetes mellitus (DM) both are rapidly emerging as public health problems in developing countries. Hypertension is the leading cause of cardiovascular disease and is also a major cause of disability, causing an estimated 13% of all deaths in the world. Diabetes mellitus, hypertension and obesity are very strongly associated with cardiovascular diseases all over the world. MATERIAL AND METHODS A cross sectional study was done among the doctors and nurse working in UCMS teaching hospital from Sep, 2020 to Feb, 2021. A total of 138 doctors and nurses were selected using a simple random sampling technique. Descriptive statistical analysis was used for the calculation of central tendency and dispersion measures. Chi- Square test was applied for categorical predictors and P value of less than 0.05 was considered as statistically significant. RESULTS Doctors formed 47 % while nurses formed 53% of the study population. Prevalence of hypertension was found to be 18% among doctors and 7% among nurses. Prevalence of diabetes mellitus was found to be 6% among doctors and 8% among nurses. Prevalence of obesity was found to be 47% among doctors and 48% among nurses. The overall prevalence of hypertension, diabetes mellitus and obesity was the order of 25%, 14% and 95% respectively. CONCLUSION These findings provide important information on prevalence of hypertension, diabetes mellitus and obesity along with its associ- ated risk factors among doctors and nurses working in UCMS teaching hospital. Preventive health measures like low fat diet, physical activity, cessation of smoking, control of alcohol and various strategies are needed for the prevention of these cardio-vascular disease among doctors and nurses working at UCMS teaching hospital.

The Essence of High-Tech Warfare in the Organizational and Institutional Security Theory of State Administration

At the turn of the 20th and 21st centuries, fundamental changes occurred in the field of international security. The world community faced fundamentally new challenges and threats. In many regions of the world, interstate rivalry was observed, which led to the outbreak of local wars and military conflicts, which mostly took the form of armed confrontation. Technological progress, the presence of significant military power, the demonstration of determination and its use transformed social relations into more conflictual ones. Gradually, more and more countries of the world are involved in local wars and military conflicts. In this context, it should be noted that the intensity and scale of hostilities during the last thirty years, which took place in different corners of the globe, testify to the growth of dynamic changes in the situation in the combat zone during the use of international coalition forces. At the same time, the strict implementation of the requirements for stable, continuous, operational and covert management of troops during their performance of combat missions prompts the world's leading countries to develop and implement new concepts of information networks and systems. It should be noted that future wars will depend on high-tech intelligence. The priority is to identify the enemy first, before he notices you; blind the enemy's sensors, be it drones or satellites; and disrupt their means and data channels, whether through cyberattacks, electronic warfare, or old-fashioned firepower. Armies will have to develop new forms and methods of application, relying on mobility, dispersion, camouflage and deception measures. Large armies that fail to invest in new technology or develop new doctrine will be overwhelmed by smaller ones that do. "We have to recognize that the old concepts of fighting large tank battles on European land are over," said Boris Johnson, the UK's prime minister, in November 2021. "There are other, more important things in which we should invest. Cyber technologies, this will be the war of the future." Three months later, Russia invaded Ukraine. So, the work defines the problem of incomplete compliance of the current state and readiness of the security and defense sector with regard to the requirements of effective countermeasures against threats to national security and their neutralization, the task of improving this activity, regarding the creation of unified management and communication systems, and horizontal connections are defined connections of these systems and electronic communication networks, which in the future will undoubtedly affect the safe functioning of the national segment of cyberspace.

Workplace learning tendencies of university librarians: A gender perspective

This article reveals the workplace learning tendencies of librarians working in state universities in Turkey in terms of gender variable. Workplace learning tendencies of librarians were categorized under three headings: interests and needs for learning, learning styles and obstacles encountered in learning processes. The research was conducted by comparison type relational survey model. In the data collection stage, a 5-point scale questionnaire consisting of 30 statements with proven validity and reliability was used. Through SPSS 22.0 program, central tendency and dispersion measures were applied in the analysis of the data process. The research population consisted of 525 librarians working in state universities in Turkey. From this population, 245 librarians were reached through simple random sampling method. The findings of the study show that compared to male librarians, female librarians think that librarianship requires continuous learning. Furthermore, while female librarians are willing to receive in-service training on professional and technological innovations, male employees tend to maintain these processes in self-directed and heutagogical approaches, and they prefer to receive in-service training in the fields of personal development and actuality. Finally, female employees state that they allocate less time for learning processes in the workplace than male employees due to the workload and obstacles they face in the workplace. The fact that the number of female librarians is higher than that of male librarians did not create any change in the context of gender. Researchers suggest applying workplace learning tendencies questionnaire to different occupational groups for future studies. This study is multidisciplinary research that deals with librarians' workplace learning in the framework of gender differences. It is anticipated that this research will contribute to the literature, since there are few studies in which the librarianship profession is handled by different disciplines.

Comparison between anthropometric measurements and indices to evaluate general and abdominal obesity, Colombia ENSIN 2015

Introduction. Excess weight represents a problem in the adult population, has increased in recent years and is associated with noncommunicable diseases. Objectives. To make comparisons between anthropometric measurements and indices and to evaluate their relationship with individual and sociodemographic variables to generate information on the use of the main measurements in the evaluation of general and abdominal obesity as indicators of cardiovascular risk. Materials and methods. Secondary analysis of the ENSIN survey for Colombia with data collected between 2015 and 2016, the 2005 Population and Housing Census of the Departamento Administrativo Nacional de Estadística (DANE) was used as a sampling frame. The sample was 44,202 households with 151,343 people aged 0 to 64 years; 70,315 records of adult population were selected for this analysis. Proportions, confidence intervals, measures of central tendency and dispersion were calculated. Results. The means of body mass index (BMI) and waist-height index were higher than the cutoff point in both sexes, while the means of waist circumference were below the cutoff point for men and higher for women (p<0.05). The prevalence of obesity by BMI was 17.5%, while abdominal obesity by waist circumference and waist-height index of 50.2% and 62.6% respectively. Conclusions. Abdominal obesity regardless of the indicator used, is about 3 times higher than general obesity by BMI and waist-height index identifies more people, especially men, with abdominal obesity compared to waist circumference.

MODERN NUMERICAL METHODS OF ANALYSIS OF STATISTICAL DATA IN THE SCHOOL COURSE

Mathematical modelling of practical statistical problems is a current topic in the school course, related to the development of various approaches and methods of modern solutions to many practical problems. The purpose of mathematical statistics is the development of methods of statistical observation and the collection and analysis of statistical data. The given article shows several numerical methods for studying mathematical statistics in the school course: measurements of central tendency, measurements of position, measurements of dispersion. Measures of central tendency indicate the “center” of the data along a number line and are usually reported as values representing the data. There are three common measures of central tendency: the arithmetic mean, the median, and the mode. Position metrics represent the three most basic positions in a list of numeric data, ordered from smallest to largest: start, end, and middle. In addition to these, the most common measures of position, quartiles and percentages, are also presented. Measures of dispersion show the degree to which the data are spread out. Among the measures of dispersion of the statistic, the rank, interquartile range, and standard deviation are presented. The practice of solving statistical problems serves to develop the skills of using probabilistic statistical concepts and methods at school, so the work presents the brief content of each method, calculation formulas, and examples.

Reduced resting beat-to-beat blood pressure variability in females with relapsing-remitting multiple sclerosis

BackgroundRelapsing-remitting multiple sclerosis (RRMS) is a demyelinating disease of the central nervous system and cardiovascular autonomic dysfunction has been well documented in this population. The sympathetic nervous system contributes to beat-to-beat blood pressure regulation primarily by baroreflex control of the peripheral vasculature which may be impaired in females with RRMS. Even at rest, attenuated sympathetic control of vasomotor tone may result in large and frequent blood pressure excursions (i.e., greater blood pressure variability). Therefore, the primary purpose of this investigation was to test the following hypotheses; (1) females with RRMS have augmented beat-to-beat blood pressure variability compared to healthy controls and (2) reduced sympathetic baroreflex sensitivity in females with RRMS is related to augmented blood pressure variability. MethodsElectrocardiogram and beat-to-beat blood pressure were continuously recorded during 8–10 min of supine rest in 26 females with clinically definite RRMS and 24 sex-, age- and BMI- matched healthy controls. Muscle sympathetic nerve activity (MSNA) was recorded in a subset of participants (MS, n = 15; CON, n = 14). Traditional statistical measurements of dispersions were used to index beat-to-beat blood pressure variability. Spontaneous sympathetic baroreflex sensitivity was quantified by sorting diastolic blood pressures into 3 mmHg bins and calculating MSNA burst incidence within each bin. Weighted linear regression was then used to account for the number of cardiac cycles in each bin and calculate slopes. Spontaneous cardiac baroreflex sensitivity was determined using the sequence method. ResultsGroups had similar resting mean arterial pressure (MAP), systolic blood pressure (SBP), diastolic blood pressure (DBP), MSNA burst frequency and MSNA burst incidence (All P > 0.05). The standard deviation and interquartile range of MAP, SBP and DBP were less in females with RRMS compared to healthy controls (All P < 0.05). There were no between groups differences in sympathetic baroreflex sensitivity or cardiac baroreflex sensitivity (Both P > 0.05) and baroreflex sensitivity measures were not related to any indices of blood pressure variability (Both P > 0.05). ConclusionThese data suggest that females with RRMS have reduced beat-to-beat blood pressure variability. However, this does not appear to be related to changes in sympathetic or cardiac baroreflex sensitivity.

Macular Alterations in Patients with Chronic Diseases in Queretaro

Background: Visual health problems and chronic-degenerative diseases have a significant impact on the Mexican population. Macular alterations are the third worldwide cause of moderate to severe visual disability. The timely detection of macular alterations and the control of chronic-degenerative diseases allow stopping or prolonging their progress, giving better visual health and quality of life. Objective: To determine the association between the main chronic degenerative diseases and macular alterations. Methods: A comparative cross-sectional observational study was carried out in patients over 60 years of age assigned to UMF 16. The selection of participants was carried out in a non-probabilistic manner. The Amsler grid test was applied as a screening to detect macular alterations, and clinical, metabolic and sociodemographic variables were also measured. For the statistical analysis we used descriptive statistics with measures of central tendency and dispersion; in the inferential analysis, Chi-Square Test, odds ratio and ANOVA were used. Results: A total of 112 patients were analyzed. The frequency of macular alterations in the right eye was 25%; and the same for the left eye. The total frequency of macular alterations was 36%. When analyzing the four groups we found the following results for qualitative variables: sex, p 0.58; education, p 0.27; CKD stage, p 0.22; smoking, p 0.22; dyslipidemia, p 0.64; obesity, p 0.72; and macular alterations, p 0.11. In the quantitative variables we find: age, p 0.1; creatinine, p 0.4; GFR, p 0.055; glucose, p 0.001; systolic pressure, p 0.04; and diastolic pressure, p 0.6.

Level of knowledge about contraception and prevention of sexually transmitted diseases among students of the Medical School of the Universidad Abierta Interamericana - Sede Rosario (Argentina), year 2023

Introduction: Sexually transmitted diseases (STDs) constitute an important public health problem worldwide, being condoms the fundamental weapon for protection against STDs.Objective: To describe the level of knowledge about contraception and prevention of sexually transmitted diseases of students from 1st to 3rd year of medical school at the Universidad Abierta Interamericana - Rosario campus in the year 2023.Materials and methods: Quantitative, observational, descriptive, cross-sectional and retrospective study, carried out at the Universidad Abierta Interamericana (UAI), Rosario, Argentina, from December 2022 to May 2023. The population consisted of students studying from the first to the third year in the first four-month period of the Medical School. The data collection instrument consisted of a survey consisting of 21 questions on contraception and STDs. The variables were summarized through measures of central position (mean) and measures of dispersion (range and standard deviation) and expressed in absolute and relative frequency. Results: A total of 70 students were analyzed of which 77% (n=54) were female and 23% (n=16) were male. The mean age was 24.6 ± 5.02 years. Sixty-four percent (n=45) belonged to the third year of medicine, 29% (n=20) to the second year and 7% (n=5) to the first year. The mean score obtained was 16.75 ± 2.01 points. Seventy-six percent had a high level of knowledge and 24% medium. The population under 25 years of age had better knowledge than the population over 25 years of age. Similarly, women and third year students have better levels of knowledge. In relation to the function, choice, classification and form of use of contraceptive methods, the students had an average of 8 ± 0.98 correct answers, which represents a high level of knowledge about contraception. Regarding the concept, form of transmission, signs and symptoms, diagnosis, treatment, complications and preventive measures of STDs the students had on average 8.73 ± 1.49 correct answers, representing a medium level of knowledge about STDs.Conclusions: Of the 70 UAI medical students surveyed, there was a higher participation of women under 25 years of age. Of these students, 76% had a high level of knowledge about contraception and STDs

Frequency of self-medication in students of the Medical School of the Universidad Abierta Interamericana, Rosario (Argentina) in the year 2023

Introduction: Self-medication is the use of medications on one's own initiative without medical prescription, treatment supervision, or diagnosis. Although in some cases it may be convenient to treat minor symptoms, irresponsible self-medication can lead to serious health consequences.Objective: To describe the frequency of self-medication in students of the Medical School of the Universidad Abierta Interamericana (UAI) - Rosario campus in the year 2023. Materials and methods: A quantitative, observational, descriptive, cross-sectional, retrospective, retrospective study was carried out at the UAI, Rosario, Argentina, from January to June 2023. The population consisted of 2nd and 5th year students of the 1st semester of the Medical School. The data collection instrument consisted of an anonymous, voluntary, self-administered survey consisting of 6 multiple-choice questions. The variables were summarized through measures of central position (mean) and measures of dispersion (range and standard deviation) and were expressed in absolute and relative frequency.Results: A total of 53 students were surveyed, of which 72% (n=38) were female and 28% (n=15) were male. The mean age was 28.58 ± 6.59 years (min: 20; max: 43). Fifty-seven percent (n=30) belonged to the fifth year of medicine and 43% (n=23) to the second year. Of these, 81% reported that the reason for self-medication was to have learned that the drug was useful for the reason for its use. The main illnesses that motivated self-medication were headache (94%), muscle pain (70%), flu (66%) and fever (64%). The types of self-medicated drugs reported were analgesics (91%), anti-influenza (66%), anti-inflammatory drugs (66%), antacids (53%), antibiotics (42%) and vitamins (34%). Ninety-eight percent stated that they had acquired medicines from pharmacies without a prescription, 26% from family medicine cabinets and 23% from relatives or friends, respectively Conclusions: It was found that all of the medical students surveyed had self-medicated at some point in their lives, with headache being the most common cause. The students reported using analgesics, anti-flu, anti-inflammatory, antacids, antibiotics and vitamins for self-medication

Level of knowledge about carbon monoxide poisoning and its prevention among students of the Medical School of the Universidad Abierta Interamericana of the city of Rosario (Argentina) in the year 2023

Introduction: Carbon monoxide (CO) poisoning is a medical emergency that, if not adequately treated, can cause neurological sequelae and even death of the patient. However, its recognition is difficult due to the fact that CO is a colorless and odorless gas and that its symptoms are non-specific and can be confused with other pathologies.Objective: To describe the level of knowledge about CO poisoning and its prevention among students in the 1st, 2nd, 3rd and 4th YEAR (1st four-month period) of the Medical School of the Universidad Abierta Interamericana (UAI) - Rosario campus in the year 2023.Materials and methods: Quantitative, observational, descriptive, cross-sectional and retrospective study. It was carried out at the UAI Rosario campus. The population consisted of students in their 1st, 2nd, 3rd and 4th year, all of them in their 1st four-month period of the UAI Medical School. The sampling was non-probabilistic by convenience. The data collection instrument consisted of an anonymous, voluntary and self-administered survey consisting of 24 questions aimed at identifying the knowledge of medical students regarding CO poisoning, its causes, symptoms, action and prevention. The variables were analyzed through absolute and relative percentage frequencies and summarized through measures of central position: mean, and measures of dispersion: standard deviation.Results: A total of 85 students were surveyed, of whom 66% were female and 34% male, with a mean age of 26.43 ± 5.86 years (min: 18; max: 43). 36% were in their first year of high school. Thirty-six percent were in their second year of medical school, 26% in their fourth year, 20% in their third year and 18% in their first year. The mean score was 13.87 ± 4.07 points (min. 5; max. 22). Fifty-six percent of the medical students surveyed presented a medium level of knowledge about CO poisoning, 32% a high level and 12% a low level.Conclusions: 56% of the surveyed medical students presented a medium level of knowledge about the causes, symptoms, methods of action and prevention of CO poisoning. Among the symptoms of CO poisoning recognized by the students were headache, fainting, nausea, vomiting, fatigue, blurred vision, confusion and difficulty breathing.

Level of knowledge on first aid in case of an accident at home of parents and/or guardians of children attending the Community Center Nº 14 of the City of Rosario, Year 2022

Introduction: First aid responds to a need in today's society and its knowledge has health, political and economic impact effects, since the subsequent evolution depends on its adequate performance and in many occasions the victim's life can be saved.Objective: To describe the level of knowledge that parents and representatives have about first aid in the event of an accident at home.Materials and Methods: A quantitative, descriptive, cross-sectional and prospective study was conducted in the Avellaneda Oeste neighborhood of Community Center Nº 14 from April 2022 to October 2022. The variables analyzed were age, sex, educational level, marital status, occupation, knowledge. The variables were analyzed through absolute and relative percentage frequencies and summarized through central position measures: mean, median and mode and non-central position measures: quartiles 1 and 3 and dispersion measures: range and standard deviation.Results: A total of 79 parents and representatives were surveyed, 77 female (97%) and 2 male (3%), with an average age of 29 ± 7.35 years (min 18, max.45). 94% were from Argentina and 6% were foreigners (2 from Bolivia, 2 from Haiti and Peru). 48% had primary education, 23% secondary, 17% technical, 11% none and 1% university. 68% were married and 32% were single. Of these, 18% were housewives, 13% full-time and part-time employees respectively, 15% students, 23% self-employed, and 19% unemployed. The most frequent accidents that occurred were cuts or injuries 90%, 86% falls and blows, 49% burns, 23% choking and drowning, 17% poisoning and 14% convulsions. 56% had a medium level of knowledge, 38% low and 6% high.Conclusions: The parents and representatives surveyed have a medium level of knowledge regarding first aid in case of accidents at home. The most frequent accidents reported were cuts, wounds, falls, blows and burns

Simultaneous Measurement of Group Refractive Index Dispersion and Thickness of Fused Silica Using a Scanning White Light Interferometer.

In this study, we simultaneously measured the group refractive index dispersion and thickness of fused silica using a scanning white light interferometer on a spectral range from 800 to 1050 nm. A delay error correction was performed using a He-Ne laser. The accuracy of the measured group refractive index dispersion of fused silica, when compared to the temperature-dependent Sellmeier equation, is within 4 × 10-5.

Measurement of Vertical Dispersion and Pollution Impact of Artificial Light at Night in Urban Environment

Excessive artificial light disrupts our lives and poses health risks. In mixed-use urban areas, commercial lighting conflicts with residential activities. Vertical towers exacerbate the issue, as lower-level lighting affects higher-level occupants, and more research is needed to understand the vertical dispersion of light and its impact on sleep disturbance. This work offers a simple mathematical model for height dependence of illuminance in an urban building. It correlates basic measurements to reduce the values of the Exponent (n) and Linear (Coeff2) coefficients in a standard power-law curve. The collection of only a few data points can help to investigate the extent of the lighting spread at various floors of the building. Even with the complex lighting environment in Hong Kong, the methodology is exercised in 8 sample buildings from 4 different neighbourhoods to show the insights from the testing results. The heights of the studied buildings range from 3 to 18 stories, and they are for residential and mixed use. While the average measured illuminance at the street level was between 37 lx and 303 lx for the 4 neighbourhoods, the average illuminance across building heights was 14 lx to 247 lx. The existence of multiple light sources on building facades disrupts the simple inverse-square relationship with a single light source. The power n values range from approximately -1.7 to -0.8, while the Coeff2 values range from 61 to 7603 for the measured buildings. These variations indicate deviations from the assumption of a single source and suggest higher luminance and the presence of light sources at higher heights. With the simple inverse-square relationship, the proposed methodology can help to determine the height where the recommended limit can be met given the light situation at the street level.

A novel primitive cubic Al-Fe-Si phase in an Al-0.5Fe-0.2Si (wt.%) alloy

We report the identification of a new ternary Al-Fe-Si phase synthesized by arc-melting. Energy dispersive X-ray spectroscopy measurements show an homogeneous chemical distribution within the intermetallic grain with an overall stoichiometry equal to Al81.0Fe13.6Si5.4 (at.%). Atomically resolved High-Angle Annular Dark Field images collected along the [001] zone-axis are consistent with a cubic structure with an unit cell parameter close to 8.9 Å. Using microdiffraction analysis, it was possible to explore the zero-order Laue zone (ZOLZ) and first-order Laue zone (FOLZ) . This electron diffraction characterization leads to the conclusion that the Al81.0Fe13.6Si5.4 (at.%) crystallizes in the Pm3̄ space group.

Statistical perspectives on the ripple index from a case study of aeolian megaripples

The ripple index (RI) is a common metric in the study of bedforms. In this work we review the application of RI to aeolian megaripples and perform a statistical analysis of field measurements. The research highlights ambiguity in how RI is calculated and used to describe and infer bedform morphometry. The statistical analysis demonstrates that although the prevailing application of RI encourages an interpretation as a deterministic quantity, it is in fact a stochastic variable with large variance and several use cases. RI can be used as an individual descriptive statistic, an aggregated descriptive statistic, or a linear predictor. We develop a simple linear model to investigate the notion of a representative RI value for megaripples. We find a value of 17.3 as a linear predictor for individual megaripples and a value of 17.6 as a linear predictor for aggregated megaripples, but show that the large variance observed in megaripple morphology mean that interpreting these values as representative of all megaripples can be misleading. This empirical finding of large variance in megaripple RI values aligns with recent work showing that megaripples are highly variable bedforms. Broadly, we recommend that all research involving RI should use it in an appropriate individual or aggregated data context and present these data with measures of dispersion.

Forecasting constraints on the baryon mass fraction in the IGM from fast radio bursts and type Ia supernovae

Fast Radio Bursts (FRBs) are millisecond transient radio events with a high energy. By identifying the origin of the burst, it is possible to measure the redshift of the host galaxy, which can be used to constrain cosmological and astrophysical parameters and test aspects of fundamental physics when combined with the dispersion measure (DM). However, some factors limit the cosmological application of FRBs: (i) the poor modelling of the fluctuations in the DM due to spatial variation in the cosmic electrons density; (ii) the fact that the fraction of baryon mass in the intergalactic medium (fIGM\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$f_{IGM}$$\\end{document}) is degenerated with some cosmological parameters; (iii) the limited knowledge about host galaxy contribution (DMhost\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$DM_{host}$$\\end{document}). In this work, we investigate the impact of different redshift distribution models of FRBs to constrain the baryon fraction in the IGM and host galaxy contribution. We use a cosmological model-independent method developed in previous work Lemos (EPJC 83:138, 2023) to perform the analysis and combine simulated FRB data from Monte Carlo simulation and supernovae data. We assume four distribution models for the FRBs: gamma-ray bursts (GRB), star formation rate (SFR), uniform and equidistant (ED). Also, we consider samples with N=15,30,100\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$N = 15, 30, 100$$\\end{document} and 500 points and different values of the fluctuations of electron density in the DM, δ=0,100,200,400,230z\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\delta = 0, 100, 200, 400, 230\\sqrt{z}$$\\end{document} pc/cm3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{3}$$\\end{document}. Our analysis shows that all the distribution models present consistent results within 2σ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$2\\sigma $$\\end{document} for the free parameters fIGM\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$f_{IGM}$$\\end{document} and DMhost,0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$DM_{host,0}$$\\end{document} and highlights the crucial role of DM fluctuations in obtaining more precise measurements.