bluuebunny/crossref_metadata_2025 huggingface dataset:
Pulverized-Coal-Fired Gasifier for Production of Carbon Monoxide and Hydrogen
Authors: Grossman P. R. , Curtis R. W.
Published: July 2022

This paper describes a pilot-plant pulverized-coal gasifier installed at the Morgantown Station of the Bureau of Mines and a semicommercial gasifier of similar design installed at the E. I. du Pont de Nemours & Company, Inc., Belle, West Virginia. A brief summary of the operating data obtained from these two units is presented and material requirements are given for this method of coal gasification. A large size unit of this design is now under construction and will go into operation next year. This will be the first commercial application of the process in this country. Details of the design that provide for handling of coal ash of widely varying fusing temperatures are given in an effort to point out those features which have contributed to continuous uninterrupted operation. Included also is a discussion of heat flow within the gasification unit to illustrate the factors involved in obtaining an economical process.
Characteristics of a Vaporizing Combustor for Aviation Gas Turbines
Authors: Pouchot W. D. , Hamm J. R.
Published: July 2022

An annular vaporizing-type combustor for an aviation gas turbine is described and its performance and operational characteristics are given. Test results show that the level of combustion efficiency at high altitudes is high and nearly constant over a wide range of fuel-air ratios. The other performance and the operational characteristics of the combustor have been found to be satisfactory. The outstanding advantage of the vaporizing combustor was its short length relative to a liquid-injection combustor developed for the same application.
Coefficients of Float-Type Variable-Area Flowmeters
Authors: Head V. P.
Published: July 2022

A uniform method of correlating flow data for all float-type variable-area meters is presented. Curves correlating the results of 73 calibrations of rotameters in ½-in. to 2-in. sizes and suitable for general flow calculation purposes are presented. Installation influences are discussed. A theoretical equation combining energy and momentum considerations is presented and compared with available data for incompressible flow.
Survey of Experimental Determinations of Heat Capacity of Ten Technically Important Gases
Authors: Masi Joseph F.
Published: July 2022

All of the literature reports of determinations of heat capacity of gases in the period 1925–1952, inclusive, are reviewed, and those pertaining to any of the ten gases—air, NH3, CO2, CO, H2, CH4 NO, N2, O2, and H2O—are tabulated. The four direct and six indirect methods used in these measurements are described briefly. By means of graphs, the reported results for several of the gases are compared with values calculated from molecular data and an equation of state. There is included a table of the most recent values of heat capacity at 1 atm for the ten gases.
Synthesis of the Four-Bar Mechanism When the Position of Two Members Is Prescribed
Authors: Shaffer B. W. , Cochin I.
Published: July 2022

The four-bar mechanism is analyzed, and a differential equation is derived which tells whether or not it is possible to find a particular design in which the position of the driver and follower are related by a prescribed function during the entire range of operation. If there is such a mechanism, the length required for each of the links may be found by substituting into the appropriate equations, also derived in this paper.
Control-System Behavior Expressed as a Deviation Ratio
Authors: Janssen J. M. L.
Published: July 2022

In order to bridge the gap between process-control practice and modern control theory, an attempt is made to reduce this theory to its bare essentials. A simple picture is drawn of what control does and how it does it, use being made of the familiar concepts of resonance and damping. Thus a theoretical background is provided for commonsense judgments on control quality and controller settings. The picture given is applicable to both feedback and feedforward control.
Experimental Flight Methods for Evaluating Frequency-Response Characteristics of Aircraft
Authors: Smith G. A. , Triplett W. C.
Published: July 2022

This paper deals mainly with methods and techniques for obtaining airplane frequency-response characteristics from transient flight measurements. After a review of the basic airplane equations of motion, the theoretical transfer function which defines the “short-period” pitch response to an elevator deflection is derived. A numerical example is used to illustrate the evaluation of an analytical transfer function from a graphical frequency response by a method which involves the use of graphical aids in conjunction with an analog computer. Finally, the effects of variations in flight speed and altitude on the airplane response are considered.
Hong–Ou–Mandel sensing via superradiant coupling of discrete fluorescent emitters
Authors: Shugayev Roman , Lu Ping , Duan Yuhua , Buric Michael
Published: July 2022

The Hong–Ou–Mandel (HOM) effect is a fascinating quantum phenomenon that defies classical explanation. Traditionally, remote nonlinear sources have been used to achieve coincident photons at the HOM beam splitter. Here, we suggest that the coincident emission source required for HOM interference can be created locally using superradiant near field coupled emitters positioned across the beam splitter gap. We show that sensitivity to permittivity changes in the beam splitter gap, and corresponding Fisher information can be substantially enhanced with HOM photon detection. Subsequently, we outline several strategies for integration of superradiant emitters with practical sensor systems. Taken together, these findings should pave a way for a wide array of near field HOM quantum sensors and novel quantum devices.
Electromagnetically induced transparency based Rydberg-atom sensor for traceable voltage measurements
Authors: Holloway Christopher L. , Prajapati Nikunjkumar , Sherman Jeffery A. , Rüfenacht Alain , Artusio-Glimpse Alexandra B. , Simons Matthew T. , Robinson Amy K. , La Mantia David S. , Norrgard Eric B.
Published: July 2022

We investigate the Stark shift in Rydberg rubidium atoms through electromagnetically induced transparency for the measurement of direct current (dc) and 60 Hz alternating current (ac) voltages. This technique has direct application to the calibration of voltage measurement instrumentation. We present experimental results for different atomic states that allow for dc and ac voltage measurements ranging from 0 to 12 V. While the state-of-the-art method for realizing the volt, the Josephson voltage standard, is significantly more accurate, the Rydberg atom-based method presented here has the potential to be a calibration standard with more favorable size, weight, power, and cost. We discuss the steps necessary to develop the Rydberg atom-based voltage measurement as a complementary method for dissemination of the voltage scale directly to the end user and discuss sources of uncertainties for these types of experiments.
Four decades of near-field acoustic holography
Authors: Fernandez-Grande Efren
Published: July 2022

The Reflections series takes a look back on historical articles from The Journal of the Acoustical Society of America that have had a significant impact on the science and practice of acoustics.
Teaching an advanced undergraduate acoustics laboratory without a laboratory: Course developments enabling teaching during the COVID-19 pandemic
Authors: Kumon Ronald E.
Published: July 2022

This paper describes ongoing developments to an advanced laboratory course at Kettering University, which is targeted to students in engineering and engineering physics and emphasizes theoretical, computational, and experimental components in the context of airborne acoustics and modal testing [cf. D. A. Russell and D. O. Ludwigsen, J. Acoust. Soc. Am. 131, 2515–2524 (2012)]. These developments have included a transition to electronic laboratory notebooks and cloud-based computing resources, incorporation of updated hardware and software, and creation and testing of a multiple-choice assessment instrument for the course. When Kettering University suddenly shifted to exclusively remote teaching in March 2020 due to the COVID-19 pandemic, many of these changes proved to be essential for enabling rapid adaptation to a situation in which a laboratory was not available for the course. Laboratory activities were rewritten by crowdsourcing archived data, videos were incorporated to illustrate dynamic phenomena, and computer simulations were used to retain student interactivity. The comparison of multiple measures, including the assessment instrument, team-based grades on project papers, and individual grades on final exams, indicates that most students were successful at learning the course material and adapting to work on team-based projects in the midst of challenging remote learning conditions.
Sound source localization using multiple ad hoc distributed microphone arrays
Authors: Hahmann Manuel , Fernandez-Grande Efren , Gunawan Henrry , Gerstoft Peter
Published: July 2022

Sound source localization is crucial for communication and sound scene analysis. This study uses direction-of-arrival estimates of multiple ad hoc distributed microphone arrays to localize sound sources in a room. An affine mapping between the independent array estimates and the source coordinates is derived from a set of calibration points. Experiments show that the affine model is sufficient to locate a source and can be calibrated to physical dimensions. A projection of the local array estimates increases localization accuracy, particularly further away from the calibrated region. Localization tests in three dimensions compare the affine approach to a nonlinear neural network.
Context effects in perception of vowels differentiated by F1 are not influenced by variability in talkers' mean F1 or F3
Authors: Mills Hannah E. , Shorey Anya E. , Theodore Rachel M. , Stilp Christian E.
Published: July 2022

Spectral properties of earlier sounds (context) influence recognition of later sounds (target). Acoustic variability in context stimuli can disrupt this process. When mean fundamental frequencies (f0’s) of preceding context sentences were highly variable across trials, shifts in target vowel categorization [due to spectral contrast effects (SCEs)] were smaller than when sentence mean f0’s were less variable; when sentences were rearranged to exhibit high or low variability in mean first formant frequencies (F1) in a given block, SCE magnitudes were equivalent [Assgari, Theodore, and Stilp (2019) J. Acoust. Soc. Am. 145(3), 1443–1454]. However, since sentences were originally chosen based on variability in mean f0, stimuli underrepresented the extent to which mean F1 could vary. Here, target vowels (/ɪ/-/ɛ/) were categorized following context sentences that varied substantially in mean F1 (experiment 1) or mean F3 (experiment 2) with variability in mean f0 held constant. In experiment 1, SCE magnitudes were equivalent whether context sentences had high or low variability in mean F1; the same pattern was observed in experiment 2 for new sentences with high or low variability in mean F3. Variability in some acoustic properties (mean f0) can be more perceptually consequential than others (mean F1, mean F3), but these results may be task-dependent.
The effect of the stratopause on the structure of the infrasound signal from the August 4, 2020, Beirut explosion
Authors: Popov O. E. , Mishenin A. A. , Kulichkov S. N. , Chunchuzov I. P. , Perepelkin V. G. , Ceranna L.
Published: July 2022

The influence of wind velocity and temperature stratification in the upper stratosphere on the waveform of the infrasound signal received at a distance of 2398 km from the epicenter of the powerful explosion in Beirut that occurred on August 4, 2020 is studied using ray trace and pseudo-differential parabolic equation (PDPE) methods. Given a high temporal variability of the wind velocity in the stratopause predicted by the European Centre for Medium-Range Weather Forecasts model, it is assumed that within the stratopause layer, the increase in effective sound speed with increasing height is very small, on the order of 1 m/s. When modeling propagation of the signal from the explosion, the presence of a fine-scale layered structure of wind velocity and temperature in the real atmosphere was also taken into account. Accounting for the scattering of infrasound by strongly anisotropic (layered) inhomogeneities of the effective sound speed allowed us to explain the appearance of “fast” stratospheric arrivals, their time durations, the time period between successive arrivals (about 110 s), and the waveform of the entire observed signal.
The Nonintuitive Contributions of Individual Quadriceps Muscles to Patellar Tracking
Authors: Han Seong-won , Sawatsky Andrew , Herzog Walter
Published: July 2022

The purpose of this study was to quantify the contribution of the individual quadriceps muscles to patellar tracking. The individual and/or combined quadriceps muscles were activated in rabbits (n = 6) during computer-controlled flexion/extension of the knee. Three-dimensional patellar tracking was measured for the vastus lateralis, vastus medialis, and rectus femoris when activated alone and when activated simultaneously at different frequencies, producing a range of knee extensor torques. Patellar tracking changed substantially as a function of knee extensor torque and differed between muscles. Specifically, when all quadriceps muscles were activated simultaneously, the patella shifted more medially and proximally and rotated and tilted more medially compared with when vastus lateralis and rectus femoris were activated alone (P < .05), whereas vastus medialis activation alone produced a similar tracking pattern to that observed when all quadriceps muscles were activated simultaneously. Furthermore, patellar tracking for a given muscle condition shifted more medially and proximally and rotated and tilted more medially with increasing knee extensor torques across the entire range of knee joint angles. The authors conclude that patellar tracking depends crucially on knee extensor force/torque and that vastus medialis affects patellar tracking in a distinctly different way than vastus lateralis and rectus femoris, which produce similar tracking patterns.
Validation of a Follow-Through Developmental Sequence for the Overarm Throw for Force in University Students
Authors: Beseler Bradley , Mesagno Christopher , Spittle Michael , Johnson Nicola F. , Harvey Jack , Talpey Scott , Plumb Mandy S.
Published: July 2022

Background: The purpose of this study was to examine the effect of the follow-through on thrown ball velocity, potentially justifying inclusion of the follow-through in Roberton’s five critical components. Method: Seventy-eight University students participated in the overarm, dominant hand, throwing task, which involved throwing a standard tennis ball with maximum force three times. Each throw was filmed by two cameras placed behind and to the open side of the thrower to assess the throwing technique. The velocity of the throws was recorded with a radar gun. Results: Results indicated that, after accounting for the effects of gender, age, and throwing experience, there was a significant effect of follow-through level on throw velocity. Analysis of covariance also revealed a significant gender effect, with males throwing significantly faster than females. Results indicated the follow-through had the second largest impact on thrown ball velocity of all six components. Discussion: These findings provide preliminary support that the follow-through should be added to Roberton’s developmental levels. The inclusion of the follow-through component could assist teachers and coaches to facilitate learner and athlete development and could also improve the accuracy of throwing development assessment.
The key micronutrient copper orchestrates broad-spectrum virus resistance in rice
Authors: Yao Shengze , Kang Jinrui , Guo Ge , Yang Zhirui , Huang Yu , Lan Ying , Zhou Tong , Wang Liying , Wei Chunhong , Xu Zhihong , Li Yi
Published: July 2022

Copper is a critical regulator of plant growth and development. However, the mechanisms by which copper responds to virus invasion are unclear. We previously showed that SPL9-mediated transcriptional activation of
miR528
adds a previously unidentified regulatory layer to the established ARGONAUTE (AGO18)–miR528–
L-ascorbate oxidase
(
AO
) antiviral defense. Here, we report that rice promotes copper accumulation in shoots by inducing copper transporter genes, including
HMA5
and
COPT
, to counteract viral infection. Copper suppresses the transcriptional activation of
miR528
by inhibiting the protein level of SPL9, thus alleviating miR528-mediated cleavage of
AO
transcripts to strengthen the antiviral response. Loss-of-function mutations in
HMA5
,
COPT1
, and
COPT5
caused a significant reduction in copper accumulation and plant viral resistance because of the increased SPL9-mediated
miR528
transcription. Gain in viral susceptibility was mitigated when
SPL9
was mutated in the
hma5
mutant background. Our study elucidates the molecular mechanisms and regulatory networks of copper homeostasis and the SPL9-miR528-AO antiviral pathway.
Risks of mining to salmonid-bearing watersheds
Authors: Sergeant Christopher J. , Sexton Erin K. , Moore Jonathan W. , Westwood Alana R. , Nagorski Sonia A. , Ebersole Joseph L. , Chambers David M. , O’Neal Sarah L. , Malison Rachel L. , Hauer F. Richard , Whited Diane C. , Weitz Jill , Caldwell Jackie , Capito Marissa , Connor Mark , Frissell Christopher A. , Knox Greg , Lowery Erin D. , Macnair Randal , Marlatt Vicki , McIntyre Jenifer K. , McPhee Megan V. , Skuce Nikki
Published: July 2022

Mining provides resources for people but can pose risks to ecosystems that support cultural keystone species. Our synthesis reviews relevant aspects of mining operations, describes the ecology of salmonid-bearing watersheds in northwestern North America, and compiles the impacts of metal and coal extraction on salmonids and their habitat. We conservatively estimate that this region encompasses nearly 4000 past producing mines, with present-day operations ranging from small placer sites to massive open-pit projects that annually mine more than 118 million metric tons of earth. Despite impact assessments that are intended to evaluate risk and inform mitigation, mines continue to harm salmonid-bearing watersheds via pathways such as toxic contaminants, stream channel burial, and flow regime alteration. To better maintain watershed processes that benefit salmonids, we highlight key windows during the mining governance life cycle for science to guide policy by more accurately accounting for stressor complexity, cumulative effects, and future environmental change.
Study of the Coherence and Entanglement of Macroscopic Quantum Interfering Alternatives
Authors: Bogdanov Yu. I. , Bogdanova N. A. , Fastovets D. V. , Lukichev V. F.
Published: July 2022

An approach has been proposed to calculate the coherence and interference characteristics of macroscopic quantum systems. A general method of the analysis of two-particle quantum systems based on the Schmidt decomposition has been presented to analyze quantum entanglement between the system and environment, as well as the coherence of interfering alternatives. Simple relations have been obtained between the coherence, interference visibility, and Schmidt number. The developed method has been applied to multimode quantum states of Schrödinger’s cat.
Effect of a brief dietary counselling intervention on emergency department cardiac chest pain presentations
Authors: Murphy Ronan , Al Rasheed Ahmed , Keaver Laura
Published: July 2022

Introduction

15% of all presentations to our emergency department last year were chest pain related. This presented an opportunity to evaluate the impact of a brief physician counselling intervention on patient-reported changes in cardio-protective foodstuff intake.

Methods

This is a prospective non-randomised before and after comparison study without controls, conducted between an emergency department presentation and a scheduled follow-up visit at a cardiac diagnostics department. Participants were recruited between February and March 2021. The selected dietary components for inclusion after review of the literature were green leafy vegetables, other coloured vegetables, wholegrains, legumes and fruits. A food frequency questionnaire was completed by patients before and after a physician counselling intervention aided by a dietary infographic. Additionally, using the transtheoretical model for health behaviour change, we assessed each patient’s evolution during the study.

Results

38 patients were recruited. For patients with total baseline consumptions of five or fewer per day, there was an increase in cardioprotective foodstuff intakes (z=−2.784 p<0.005 effect size 0.39). Corresponding to this, there was a participant shift observed towards theactionandmaintenancephases of behaviour change from thecontemplationandpreparationphases.

Discussion

We demonstrated a statistically significant change with moderate effect size using a simple infographic, coupled with brief physician counselling, to promote increased intake of cardioprotective foodstuffs by patients with poor baseline intakes (<5 cardio-protective foods per day) and known modifiable risk factors for ischaemic heart disease.

Conclusion

Diet is one arm in the prevention of cardiovascular disease that is often neglected by physicians. This study found that a brief dietary counselling intervention applied in an emergency department setting, administered by non-nutritionists can have a role in changing patient dietary behaviour.
Association of periodic fasting with lower severity of COVID-19 outcomes in the SARS-CoV-2 prevaccine era: an observational cohort from the INSPIRE registry
Authors: Horne Benjamin D , May Heidi T , Muhlestein Joseph B , Le Viet T , Bair Tami L , Knowlton Kirk U , Anderson Jeffrey L
Published: July 2022

Objectives

Intermittent fasting boosts some host defence mechanisms while modulating the inflammatory response. Lower-frequency fasting is associated with greater survival and lower risk from COVID-19-related comorbidities. This study evaluated associations of periodic fasting with COVID-19 severity and, secondarily, initial infection by SARS-CoV-2.

Design

Prospective longitudinal observational cohort study.

Setting

Single-centre secondary care facility in Salt Lake City, Utah, USA with follow-up across a 24-hospital integrated healthcare system.

Participants

Patients enrolled in the INSPIRE registry in 2013–2020 were studied for the primary outcome if they tested positive for SARS-CoV-2 during March 2020 to February 2021 (n=205) or, for the secondary outcome, if they had any SARS-CoV-2 test result (n=1524).

Interventions

No treatment assignments were made; individuals reported their personal history of routine periodic fasting across their life span.

Main outcome measures

A composite of mortality or hospitalisation was the primary outcome and evaluated by Cox regression through February 2021 with multivariable analyses considering 36 covariables. The secondary outcome was whether a patient tested positive for SARS-CoV-2.

Results

Subjects engaging in periodic fasting (n=73, 35.6%) did so for 40.4±20.6 years (max: 81.9 years) prior to COVID-19 diagnosis. The composite outcome occurred in 11.0% of periodic fasters and 28.8% of non-fasters (p=0.013), with HR=0.61 (95% CI 0.42 to 0.90) favouring fasting. Multivariable analyses confirmed this association. Other predictors of hospitalisation/mortality were age, Hispanic ethnicity, prior MI, prior TIA and renal failure, with trends for race, smoking, hyperlipidaemia, coronary disease, diabetes, heart failure and anxiety, but not alcohol use. In secondary analysis, COVID-19 was diagnosed in 14.3% of fasters and 13.0% of non-fasters (p=0.51).

Conclusions

Routine periodic fasting was associated with a lower risk of hospitalisation or mortality in patients with COVID-19. Fasting may be a complementary therapy to vaccination that could provide immune support and hyperinflammation control during and beyond the pandemic.

Trial registration

Clinicaltrials.gov,NCT02450006(the INSPIRE registry).
Integrating hepatitis B care and treatment with existing HIV services is possible: cost of integrated HIV and hepatitis B treatment in a low-resource setting: a cross-sectional hospital-based cost-minimisation assessment
Authors: Ejalu David Livingstone , Mutyoba Joan N , Wandera Claude , Seremba Emmanuel , Kambugu Andrew , Muganzi Alex , Beyagira Racheal , Amandua Jacinto , Mugagga Kaggwa , Easterbrook Philippa , Ocama Ponsiano
Published: July 2022

Background

Hepatitis B and HIV care share health system challenges in the implementation of primary prevention, screening, early linkage to care, monitoring of therapeutic success and long-term medication adherence.

Setting

Arua regional referral hospital (RRH) and Koboko district hospital (DH), the West Nile region of Uganda.

Design

A cross-sectional hospital-based cost minimisation study from the providers’ perspective considers financial costs to measure the amount of money spent on resources used in the stand-alone and integrated pathways.

Data sources

Clinic inputs and procurement invoices, budgetary documents, open market information and expert opinion. Data were extracted from 3121 files of HIV and hepatitis B virus (HBV) monoinfected patients from the two study sites.

Objective

To estimate provider costs associated with running an integrated HBV and HIV clinical pathway for patients on lifelong treatment in low-resource setting in Uganda.

Outcome measures

The annual cost per patient was simulated based on the total amount of resources spent for all the expected number of patient visits to the facility for HBV or HIV care per year.

Results

Findings showed that Arua hospital had a higher cost per patient in both clinics than did Koboko Hospital. The cost per HBV patient was US$163.59 in Arua and US$145.76 in Koboko while the cost per HIV patient was US$176.52 in Arua and US$173.23 in Koboko. The integration resulted in a total saving of US$36.73 per patient per year in Arua RRH and US$17.5 in Koboko DH.

Conclusion

The application of the integrated Pathway in HIV and HBV patient management could improve hospital cost efficiency compared with operating stand-alone clinics.
Implementing delirium screening in the emergency department: a quality improvement project
Authors: Martin Louise , Lyons Marian , Patton Andrew , O Driscoll Maighread , McLoughlin Kara , Hannon Evelyn , Deasy Conor
Published: July 2022

Introduction

Delirium is a serious medical condition that is common in older adults in acute settings. Clinical practice guidelines recommend that all older patients in acute care settings should be screened for delirium using standardised outcome measures.

Problem

In our institution, an audit showed that only 16% of older adults presenting to the emergency department were screened for delirium. The goal of this project was to increase the number of patients being screened for delirium using Lean Six Sigma (LSS) methodology and tools and a multidisciplinary approach.

Method

A multidisciplinary team in the emergency department used LSS tools and methodology over a 12-week period to first identify why patients were not being screened for delirium using root cause analysis and second to implement a multifaceted intervention including education, audits and feedback, documentation changes and team huddles. An audit was performed at the 11th week of the project to measure how many patients were being screened for delirium post project intervention.

Results

Results at 5 weeks post intervention (11th week of project) showed that the percentage of patients being screened for delirium had increased from 16% to 82%. A follow-up audit at 17 weeks post intervention showed a further improvement in delirium screening to 92%.

Conclusion

Applying LSS tools and methodology resulted in a healthcare quality improvement. Delirium screening in an emergency department can be improved through multifaceted interventions including education, documentation changes and team huddle changes.
Attrition and associated factors among children living with HIV at a tertiary hospital in Eritrea: a retrospective cohort analysis
Authors: Mengistu Samuel Tekle , Ghebremeskel Ghirmay Ghebrekidan , Rezene Aron , Idris Mahmud Mohammed , Tikue Tsegereda Gebrehiwot , Hamida Mohammed Elfatih , Achila Oliver Okoth
Published: July 2022

Background

Reducing attrition in paediatric HIV-positive patients using combined antiretroviral therapy (cART) programmes in sub-Saharan Africa is a challenge. This study explored the rates and predictors of attrition in children started on cART in Asmara, Eritrea.

Methods

This was a retrospective cohort study using data from all paediatric patients on cART between 2005 and 2020, conducted at the Orotta National Referral and Teaching Hospital. Kaplan-Meier estimates of the likelihood of attrition and multivariate Cox proportional hazards models were used to assess the factors associated with attrition. All p values were two sided and p<0.05 was considered statistically significant.

Results

The study enrolled 710 participants with 374 boys (52.7%) and 336 girls (47.3%). After 5364 person-years’ (PY) follow-up, attrition occurred in 172 (24.2%) patients: 65 (9.2%) died and 107 (15.1%) were lost to follow-up (LTFU). The crude incidence rate of attrition was 3.2 events/100 PY, mortality rate was 2.7/100 PY and LTFU was 1.2/100 PY. The independent predictors of attrition included male sex (adjusted HR (AHR)=1.6, 95% CI: 1 to 2.4), residence outside Zoba Maekel (AHR=1.5, 95% CI: 1 to 2.3), later enrolment years (2010–2015: AHR=3.2, 95% CI: 1.9 to 5.3; >2015: AHR=6.1, 95% CI: 3 to 12.2), WHO body mass index-for-age z-score <−2 (AHR=1.4, 95% CI: 0.9 to 2.1), advanced HIV disease (WHO III or IV) at enrolment (AHR=2.2, 95% CI: 1.2 to 3.9), and initiation of zidovudine+lamivudine or other cART backbones (unadjusted HR (UHR)=2, 95% CI: 1.2 to 3.2). In contrast, a reduced likelihood of attrition was observed in children with a record of cART changes (UHR=0.2, 95% CI: 0.15 to 0.4).

Conclusion

A low incidence of attrition was observed in this study. However, the high mortality rate in the first 24 months of treatment and late presentation are concerning. Therefore, data-driven interventions for improving programme quality and outcomes should be prioritised.
Quadratic metric-affine gravity: solving for the affine-connection
Authors: Iosifidis Damianos
Published: July 2022

We consider the most general 11 parameter parity even quadratic Metric-Affine Theory whose action consists of the usual Einstein–Hilbert plus the 11 quadratic terms in torsion, non-metricity as well as their mixing. By following a certain procedure and using a simple trick we are able to find the unique solution of the affine connection in terms of an arbitrary hypermomentum. Given a fairly general non-degeneracy condition our result provides the exact form of the affine connection for all types of matter. Subsequently we compute the forms of torsion and non-metricity in terms of their sources (hypermomentum tensor) and also express the metric field equations in effectively Einstein’s GR with modified source terms that depend on the hypermomentum and its derivatives. We show that in the absence of matter the Theory always reduces to GR. Finally we generalize our result and find the form of the connection for a wider class of quadratic Theories.
Weak supersymmetric su(N|1) quantum systems
Authors: Smilga Andrei
Published: July 2022

In this paper, we present several examples of supersymmetric quantum mechanical systems with weak superalgebra [Formula: see text]. One of them is the weak [Formula: see text] oscillator. It has a singlet ground state, [Formula: see text] degenerate states at the first excited level, etc. Starting from the level [Formula: see text], the system has complete supersymmetric multiplets at each level involving [Formula: see text] degenerate states. Due to the fact that the supermultiplets are not complete for [Formula: see text], the Witten index represents a nontrivial function of [Formula: see text].

This system can be deformed with keeping the algebra intact. The index is invariant under such deformation. The deformed system is not exactly solved, but the invariance of the index implies that the energies of the states at the first [Formula: see text] levels of the spectrum are not shifted, and we are dealing with a quasi-exactly solvable system.

Another system represents a weak generalization of the superconformal mechanics with [Formula: see text] complex supercharges. Also in this case, starting from a certain energy, the spectrum involves only complete supersymmetric [Formula: see text]-plets. (There also exist normalizable states with lower energies, but they do not have normalizable superpartners. To keep supersymmetry, we have to eliminate these states.)
Effects of rotating frames of reference and Cornell-type potential on modified quantum oscillator field in magnetic cosmic string space–time
Authors: Ahmed Faizuddin
Published: July 2022

In this paper, a relativistic quantum oscillator model analog to the Dirac oscillator under the effects of a uniform rotating frame of reference in a five-dimensional magnetic cosmic string space–time subject to a Cornell-type scalar potential is analyzed. We discuss the influences of topological defects, the magnetic flux, and the scalar potential on the eigenvalue solution of the wave equation. We see that the presence of uniform rotating frame causes the perturbation of the energy spectrum around [Formula: see text] and observe the Sagnac-type effect. Furthermore, we show that the energy eigenvalue depends on the geometric quantum phase which gives rise to the gravitational analog of the Aharonov–Bohm effect.
VIX Implied Volatility as a Time-Invariant, Stationary Assessor of Market Nervousness/Uncertainty
Authors: Ronn Ehud I.
Published: July 2022

Financial markets serve numerous roles, amongst them of course is the uncoerced exchange of securities. In addition to that role, they serve a very useful function of conveying to market observers the information about the future, with the challenge being our ability to elicit and interpret that information. This paper addresses that latter function regarding the option markets which provide the value for the VIX 30-day implied volatility on the S&P 500 Market Index. It is demonstrated that the peak values of VIX during Persian Gulf I (1990–1991) and Persian Gulf II (2003) were nearly identical. The VIX measure is then computed during the crises of 2008–2009, 2020 and 2022. Critically, this paper demonstrates the valuable informational content provided by the “term structure of VIX”, the set of cross-sectional implied volatilities observed with different times to expiration.
On the primitivity of the AES-128 key-schedule
Authors: Aragona Riccardo , Civino Roberto , Volta Francesca Dalla
Published: July 2022

The key-scheduling algorithm in the AES is the component responsible for selecting from the master key the sequence of round keys to be xor-ed to the partially encrypted state at each iteration. We consider here the group [Formula: see text] generated by the action of the AES-128 key-scheduling operation, and we prove that the smallest group containing [Formula: see text] and all the translations of the message space is primitive. As a consequence, we obtain that no linear partition of the message space can be invariant under its action.
Grothendieck groups of purely infinite simple Leavitt path algebras for punctured power graphs of finite groups
Authors: Das Sumanta , Sen M. K. , Maity S. K.
Published: July 2022

In [S. Das, M. K. Sen and S. K. Maity, Leavitt path algebras for power graphs of finite groups, J. Algebra Appl., doi:10.1142/S0219498822502097], we studied several algebraic properties of Leavitt path algebra of the directed power graph [Formula: see text] and also of the directed punctured power graph [Formula: see text] of a finite group [Formula: see text]. In this paper, we compute the Grothendieck group of purely infinite simple Leavitt path algebra of the directed punctured power graph of a finite group.
A generalization of graded prime hyperideals over graded multiplicative hyperrings
Authors: Ghiasvand P. , Raeisi M. , Mirvakili S.
Published: July 2022

Let [Formula: see text] be a group with identity [Formula: see text] and [Formula: see text] be a graded multiplicative hyperring. In this paper, we introduce and study the notion of graded [Formula: see text]-absorbing hyperideals of [Formula: see text] as a generalization of prime hyperideals. Many properties, examples and characterizations of graded [Formula: see text]-absorbing hyperideals of [Formula: see text] are introduced. Moreover, we investigate the behavior of this structure under homogeneous components, graded hyperring homomorphisms, Cartesian product and fundamental relations. We consider the fundamental relation [Formula: see text] on [Formula: see text] as the smallest equivalence relation such that the quotient [Formula: see text] is a ring. Also, we show that if [Formula: see text] is a graded hyperring, then [Formula: see text] is a graded ring.
Numerical Simulations of Lightning Strikes to Carbon Fiber Reinforced Polymers Using a Multi-Variable Approach
Authors: Lendrum Peter A. , Ye Lin , Chang Li , Yang Richard Chunhui
Published: July 2022

Carbon fiber-reinforced polymer (CFRP) composite materials are being employed widely in the manufacturing of next-generation aircraft because of their superior mechanical properties compared to those of metallic-based materials. Owing to growing interest in CFRP materials from large commercial and military aircraft manufacturers, such as Boeing and Airbus, research that investigates lightning strikes and associated damage is of paramount importance, as the fiber-polymer composite is highly resistive to electrical current. The high resistivity of traditional CFRP materials means that they are susceptible to extreme damage caused by the Joule effect, also known as resistive heating. The aim of the study presented in this paper is to determine and quantify the effectiveness of a developed multi-variable pyrolysis approach to model the transient material degradation during a lightning strike event. The study employs the finite element method (FEM) in the form of a coupled thermal–electrical analysis in conjunction with a user subroutine available in Abaqus. A parametric study was conducted to compare three different peak current values (20[Formula: see text]kA, 30[Formula: see text]kA and 40[Formula: see text]kA) based on a model that utilized pyrolysis-dependent material constituents as well as a novel model for specific heat capacity. The study also included a heat transfer step for a cool-down process. The results obtained from the model developed have strong agreement with the surface damage area and depth of damage compared with those from experimental analysis in literature.
How Light Polarizations Affect the Localized Surface Plasmon Resonance of Asymmetric Palladium Nanostructures
Authors: El Samad Samaya , Marhaba Salem
Published: July 2022

Divers spectroscopy techniques and advances imaging are elucidated when employing light in a controlled manner. One of the features of the light focusing fields is the localized surface plasmon resonance (LSPR). In this paper, we study the LSPRs for different arrangements of palladium (Pd) nanostructures with respect to light polarization in the visible and near-infrared regions. The extinction cross-section spectrum of asymmetric nanostructures is measured using far field spectroscopy technique and is calculated using Finite Element Method (FEM). The spectra of the nanostructures various arrangements recorded from the two methods are in very good agreement. Depending on the light polarization, the nanostructures produce strong plasmonic coupling. This is represented by the induction of dipole and quadrupole LSPR modes. A clear enhancement of the extinction spectrum has been evidenced by increasing the number of particles of nanostructures. The main advantage of the transition metallic nanostructures of different arrangements lies in the generation of a highly enhanced electromagnetic field accompanied by a redshift of LSPR spectrum that can be exploited in diverse applications.
Performance Evaluation of SAW-Based Hydrogen Gas Sensors with Different IDT Geometries
Authors: Harathi Nimmala , Subramanian Kavitha , Sarkar Argha , Selvarajan Rajakumar
Published: July 2022

This paper presents the performance of three different micro-electro mechanical systems (MEMS)-based surface acoustic wave (SAW) devices for sensing hydrogen gas. All three devices, namely, Device 1, Device 2 and Device 3, were constructed with the same dimensions but with varying geometries. The devices were simulated using COMSOL Multiphysics and various analyses such as deflection, electric potential, frequency shift with respect to the concentration of hydrogen gas, total capacitance of interdigital transducers (IDTs) and sensitivity were performed using finite element modeling. The devices were constructed with a lithium-niobate piezoelectric substrate and a ZnO sensing layer. The performance of MEMS-based SAW devices can be improved by doping with nanomaterials. The devices were tested with hydrogen gas at concentration from 10[Formula: see text]ppm to 100[Formula: see text]ppm. Owing to the mass loading effect, Device 3 exhibited maximum sensitivity and a close approximation of the simulated results with the theoretical results.
Synthesis and Gelling Performances of 4-Biphenylcarboxy Protected Dipeptide
Authors: Murmu Purnima A , Chowdhury Srayoshi Roy , Haldar Debasish
Published: July 2022

In this paper, we have designed and synthesized a terminally protected dipeptide Ala-Phe 2 with 4-biphenylcarboxy protecting group at the N-terminus and methyl ester protecting group at C-terminus. Interestingly, the dipeptide formed organogel in different aromatic solvents such as benzene, toluene, xylene, chlorobenzene and 1,2-dichlorobenzene. However, the dipeptide fails to form gel in hexane, EtOAc, DCM, acetonitrile, MeOH, EtOH, diesel and kerosene under same condition. From X-ray crystallography, the peptide 1, 4-biphenylcarboxy protected alanine self-assembled through intermolecular hydrogen bonding and [Formula: see text]–[Formula: see text] stacking interactions to parallel sheet like structure however that fails to form organogel under same condition. The minimum gelation concentration (MGC) of the terminally protected dipeptide for toluene is 8[Formula: see text]mg/mL. From rheology study, the storage modulus of the organogel was approximately an order of magnitude larger than the loss modulus, which indicates the elastic nature of the gel. FE-SEM images of the xerogel exhibit twisted fiber morphology and a danse fiber network that entangled and encapsulated solvents to form orgenogel.
VAR Analysis on the Relationship between Consumer Price Index, Real Interest and Exchange Rate: The Case of Turkey
Authors: Sünbül Ersin
Published: July 2022

The study aims to examine the relationships between variables from different perspectives by using Turkey’s Real exchange rate (TL/USD), Real interest rate and Consumer price index data. Data from 2012M7 to 2021M12 were used in the study. In order to examine the relationships between the variables, seasonality tests and stationarity studies, which are among the time series analysis methods, were performed. Then, the model was estimated within the scope of VAR Analysis, the compatibility of the model with the real data was checked, the validity and reliability tests of the model were made and the residuals were examined. Inter-variable Impact Response Function and Variance Decomposition statistics are discussed for the model that meets all assumptions. The use of current data in the study and the use of graphics for qualitative evaluation contributed to the literature. As a result of this study, it has been determined that the consumer price index moves independently of other variables, and there is a limited relationship between exchange rate and real interest in every respect. In the first part of the study, the introduction and the theoretical framework are discussed. In the second part, the literature is examined, and in the third part, the methods and applications used in the study are given. The last part is the conclusion and discussion.
Oil Transport Following theDeepwater HorizonBlowout
Authors: Boufadel Michel C. , Özgökmen Tamay , Socolofsky Scott A. , Kourafalou Vassiliki H. , Liu Ruixue , Lee Kenneth
Published: July 2022

The Deepwater Horizon oil spill in the Gulf of Mexico in 2010 was the largest in US history, covering more than 1,000 km of shorelines and causing losses that exceeded $50 billion. While oil transformation processes are understood at the laboratory scale, the extent of the Deepwater Horizon spill made it challenging to integrate these processes in the field. This review tracks the Deepwater Horizon oil during its journey from the Mississippi Canyon block 252 (MC252) wellhead, first discussing the formation of the oil and gas plume and the ensuing oil droplet size distribution, then focusing on the behavior of the oil on the water surface with and without waves. It then reports on massive drifter experiments in the Gulf of Mexico and the impact of the Mississippi River on the oil transport. Finally, it concludes by addressing the formation of oil–particle aggregates. Although physical processes lend themselves to numerical modeling, we attempted to elucidate them without using advanced modeling, as our goal is to enhance communication among scientists, engineers, and other entities interested in oil spills.
From the Editor: The Next Generation
Authors: Kelly Rob
Published: July 2022

Sorry, Star Trek fans, the TV series is not the topic of interest here. Instead, the starting of the fourth decade of Interface calls for not only looking back, but also looking forward. I looked back in the Spring 2022 editorial, with a sneak peek of the future of an all-digital Interface. I am happy to note that the print-on-demand option has already been a big hit for those with the continued desire for a tactile reading experience, not to mention the best-looking covers for displays on coffee tables worldwide. Now is the time to look forward and start involving the next generation of members across all the activities of the Society.
Websites/Podcasts of Note - Summer 2022
Authors: Suroviec Alice H.
Published: July 2022

Websites and Podcasts of Note suggested for you by Alice Suroviec
A Recommendation Model for College English Digital Teaching Resources Using Collaborative Filtering and Few-Shot Learning Technology
Authors: Li Juan
Published: July 2022

This study designs and implements a digital English instructional resource management recommendation system based on collaborative filtering technology based on CF research and the construction of digital English instructional resources. This study designs the system with B/S structure combined with hierarchical design architecture, plans the overall design goal, architecture design, compilation structure, and key technologies, and designs and implements the system’s core modules on the basis of fully analysing the functional and nonfunctional requirements of personalized educational resource recommendation system. Furthermore, the traditional CF has been improved to address scalability, data sparseness, and user cold start in the recommendation process. The evaluation results show that this algorithm has a recall rate of 96.37% and a system resource recommendation accuracy rate of 95.31%, both of which are higher than the traditional method’s 6.37%. This algorithm can overcome the drawbacks of traditional algorithms, improve recommendation accuracy, and efficiently provide high-quality English teaching resources. Educators and students will be more likely to find high-quality digital English instructional resources if they use the instructional resource system proposed in this study.