bluuebunny/crossref_metadata_2025_split huggingface dataset:
High Order Accuracy in the Solution of Partial Differential Equations by Resistor Networks
Authors: Landau H. G. 
Published: June 2021

Abstract
In the practical solution of partial differential equations, very high accuracy is sometimes needed, particularly when the derivatives of the solution are the quantities in which we are interested. A procedure is given here for obtaining this high accuracy by a combined numerical and electric resistor-network method. The equation is first solved approximately on the resistor network; then the residuals in the corresponding finite-difference equation are evaluated numerically. These residuals are used as current inputs to the nodes of the network to obtain a correction to the first solution. If the errors in the first solution (including both experimental and lumping errors) are of the order of a few per cent, then the errors in the corrected solution will be of the order of a few hundredths of 1 per cent. The method makes possible accurate solutions without very stringent requirements on the precision of the resistors and other components of the electric circuit.
Reflection of an Acoustic Step Wave From an Elastic Cylinder
Authors: Skalak Richard , Friedman M. B. 
Published: June 2021

Abstract
An elastic cylinder, circular in section and infinite in length, is considered in an infinite acoustic fluid. The object of this paper is the determination of the reflected and diffracted pressure fields at large distances resulting from a plane step wave of pressure impinging on the cylinder and moving in a direction normal to the axis of the cylinder. A formal solution is obtained for the general case of an elastic cylinder. Numerical results are computed for rigid, fixed cylinders, and for rigid, floating cylinders. Two different methods are used to achieve results in the different ranges of time which are of interest. A short time approximation is developed by the use of a double integral-transform method. A mode approach and a single integral transform are used for later times. The results show that the reflected pulse decays quickly, within a time on the order of the transit time of the original wave across the cylinder.
Torsion and Flexure of Slender Solid Sections
Authors: Carter W. J. 
Published: June 2021

Abstract
The solution of the torsion problem for a slender rectangular section has been made previously by approximate methods based on the Prandtl membrane analogy. In this paper approximate methods are employed in the solution of both the torsion and flexural shear problem for slender sections having a variety of shapes, most of them being doubly symmetric. Solutions obtained in this manner are compared with exact solutions, when these are available, and otherwise with solutions obtained by relaxation. It is shown that approximate methods provide an adequate solution for elements such as compressor-turbine blades when pretwist and taper can be neglected. Some attention is given to the problem of elastic-plastic torsion and elastic-plastic flexural shear of slender sections.
Displacement Discontinuity in the Elastic Half-Space
Authors: Rongved Leif , Frasier J. T. 
Published: June 2021

Abstract
The displacement generated by an arbitrary displacement discontinuity over a plane bounded area in a semi-infinite, isotropic, elastic solid is determined. The solution is given in terms of integrals over the area of discontinuity. As an example, the case of a constant displacement discontinuity over a rectangular area parallel to the boundary is worked out in closed form.
Torsion of Cylindrical and Prismatic Bars in the Presence of Steady Creep
Authors: Patel S. A. , Venkatraman B. , Hodge P. G. 
Published: June 2021

Abstract
This paper is concerned with the steady creep behavior of cylindrical and prismatic bars in which the deformations are caused by pure torsion. The creep problem is first reduced to one in nonlinear elasticity by means of the elastic analog. The elastic analysis is then carried out by means of the principles of minimum energies. These principles yield upper and lower bounds on the angle of twist. Closed-form solutions also are presented for some cross sections.
Unbalanced Inertia Forces in Slider-Crank Mechanisms of Large Eccentricity
Authors: Mewes Ernst 
Published: June 2021

Abstract
An analysis of the various harmonic orders of the inertia forces in offset slider-crank mechanisms is presented. The formulas given here are valid for all practical values of eccentricity ratio (ratio of offset to length of connecting rod) and crank to connecting rod ratio. The influence of the latter ratio on the force components is evaluated with infinite series, whereas such is not the case for the eccentricity ratio. Rules for the full or partial balance of harmonic components of the first or any other single order are given.
Ducted Fan Design Theory
Authors: Van Niekerk C. G. 
Published: June 2021

Abstract
A theory is outlined by means of which it is possible to design ducted fans directly and without having to choose any parameters in an arbitrary fashion. Optimum sizes and fan speeds are theoretically determined. The design of two fans, one having inlet guide vanes and the other of the low slip-stream-rotation type having NPL straighteners and often used in wind tunnels, are considered by way of example. While achieving a considerable degree of rationality, the theory introduces a concept of annulus efficiency that is still of an empirical nature. The empiricism is due to a present lack of knowledge about three-dimensional fan losses, and suggests further investigation.
Natural Forcing Functions in Nonlinear Systems
Authors: Harvey T. J. 
Published: June 2021

Abstract
The response of nonlinear, second-order systems is examined from a new point of view which greatly simplifies presentation of the usual frequency-response diagrams. The use of “natural” forcing functions results in a general equation relating the maximum amplitude of the applied force to the maximum amplitude of the restoring force. The relationship is found to be a function of the ratio of the period of free oscillation to the period of the forcing function. The results apply for any second-order system without damping and with a nonlinear (or linear) restoring force. The special cases of a linear system and of Duffing’s equation are considered to illustrate similarities as well as differences between treatment of linear and nonlinear frequency-response problems.
Kinematic Drift of Single-Axis Gyroscopes
Authors: Cannon R. H. 
Published: June 2021

Abstract
A gyroscope can incur steady drift by kinematically rectifying angular vibrations of the platform on which it is mounted. The phenomenon, for an unrestrained single-degree-of-freedom gyro, results from oscillatory precession of the gyro momentum vector from its nominal spatial orientation, so that it senses platform motions about axes other than the one it is controlling. The magnitude of the drift can be accurately predicted and the vibration climate of the platform restricted accordingly. Quantitative experimental verification is presented.
Coupled Vibrations of Thin-Walled Beams of Open Cross Section
Authors: Gere J. M. , Lin Y. K. 
Published: June 2021

Abstract
The determination of coupled frequencies of free vibration for beams of nonsymmetric, open cross section is discussed in this paper. Beams with various end conditions, including simple supports, fixed ends and a cantilever, are considered. Results of both exact and approximate analyses are presented. For practical use, a simple approximate formula for determining frequencies of vibration for beams with any end conditions is given. The accuracy of the approximate formula is shown by comparison with results obtained by the exact method. The exact calculations were carried out on an IBM 605 Card Programmed Calculator.
Contact Stresses Under Combined Pressure and Twist
Authors: Hetényi M. , McDonald P. H. 
Published: June 2021

Abstract
An analytical solution is presented for the case when an elastic sphere is pressed against an elastic half-space and twisted until complete slip occurs. Formulas are derived for the stress and displacement components, their evaluation is illustrated by numerical examples, and comparisons are made with the results of photoelastic tests. These tests also furnished an experimental verification of the assumption that the tangential-surface traction is proportional at every point to the normal pressure within the sliding-contact area, the proportionality constant being the coefficient of friction.
A Theory of Elastic, Plastic, and Creep Deformations of an Initially Isotropic Material Showing Anisotropic Strain-Hardening, Creep Recovery, and Secondary Creep
Authors: Besseling J. F. 
Published: June 2021

Abstract
Stress-strain relations are given for an initially isotropic material, which is macroscopically homogeneous, but inhomogeneous on a microscopic scale. An element of volume is considered to be composed of various portions, which can be represented by subelements showing secondary creep and isotropic work-hardening in plastic deformation. If the condition is imposed that all subelements of an element of volume are subjected to the same total strain, it is demonstrated that the inelastic stress-strain relations of the material show anisotropic strain-hardening, creep recovery, and primary and secondary creep due to the nonuniform energy dissipation in deformation of the sub-elements. Only quasi-static deformations under isothermal conditions are considered. The theory is restricted to small total strains.
A Fresh Test of the Epstein Equations for Cylinders
Authors: Kennard E. H. 
Published: June 2021

Abstract
Objections that have been raised against Epstein’s equations of motion for uniform cylindrical shells and the author’s extensions and conclusions from them are considered. A direct proof is offered that the equations must hold, and further reasons are given for believing that they can be used in practice, at least as a basis for obtaining rationally founded approximations.
Progressive myoclonic epilepsy due to rare mitochondrial ND6 mutation, m.14487T>C
Authors: Khoo Anthony , Naidu Saadnah , Wijayendran Surapi Bhairavi , Merve Ashirwad , Bremner Fion , Sidhu Meneka Kaur 
Published: June 2021

IntroductionMitochondrial diseases exhibit wide phenotypic heterogeneity, and can present as progressive myoclonic epilepsy.SummaryWe report a case of adult-onset drug-resistant epilepsy, cortical myoclonus and bilateral optic neuropathies due to m.14487T>C, a rare mitochondrial gene mutation identified on whole-genome sequencing. This mutation, which affects the NADH dehydrogenase 6 (ND6) subunit of the mitochondrial respiratory chain, is most commonly implicated in cases of infantile-onset Leigh syndrome, although a broader phenotypic spectrum including migraine with aura and progressive myoclonic epilepsy have been described. Serial MRI scans over a 2-year period demonstrated the interval development of bihemispheric stroke-like lesions. Giant somatosensory evoked potentials and short-duration myoclonic jerks with craniocaudal spread on surface electromyography were consistent with cortical myoclonus. Optical coherence tomography showed bilateral symmetric thinning of the nerve fibre layer in the papillomacular bundles.ConclusionWhole-genome sequencing can help to provide a definitive diagnosis for mitochondrial disease and should be considered in situations where clinical suspicion remains high despite normal genetic panels or muscle histopathology. Mitochondrial disease can present as adult-onset progressive myoclonic epilepsy, and bilateral optic neuropathies can be a striking feature of ND6 mitochondrial gene mutations. In our case, severe cortical myoclonus affecting speech and swallowing remained highly drug-resistant, however, symptomatic benefit was derived from targeted onabotulinum toxin A injections.
Cancer Treatment Helpline: a retrospective study of the NHS Tayside experience
Authors: Trip Ilse , George Sherie , Thomson Micheal , Petty Russell D , Baxter Mark A 
Published: June 2021

BackgroundTreatment-related toxicity and delays in the management of this toxicity can impact the outcomes of patient with cancer. In Scotland, a national cancer helpline was established to provide triage assessment for patients receiving systemic anticancer therapy (SACT) in an attempt to minimise delays in toxicity management. In this article, we describe the use and impact of the helpline in our region over the last 5 years.MethodsPatients who contacted the NHS Tayside cancer helpline between 1 January 2016 and 31 December 2020 were retrospectively identified. Patient demographics as well as the reason and outcome of each call was recorded. A descriptive analysis was performed.Results6562 individual patients received SACT and 8385 calls were recorded during the time period. Median age of callers was 63 years (range 17–98) and 59.2% were women. Use of the helpline increased by 83.6% between 2016 and 2020, driven by an increase in in-hours calls. 41% of calls required review by a healthcare professional only, 24% required review and admission and the remaining 35% telephone advice only. The majority of cases (85%) were either assessed or advised solely by oncology. The proportional use of general practitioner services has decreased.ConclusionsThe helpline provides a way for patients to report symptoms directly to their clinical team and receive appropriate specialist advice at an early stage. We demonstrate that most of these calls can be managed solely by our oncology team. This system can reduce pressure on other parts of the local health system.
Reduced rate of postpartum readmissions among homeless compared with non-homeless women in New York: a population-based study using serial, cross-sectional data
Authors: Sakai-Bizmark Rie , Kumamaru Hiraku , Estevez Dennys , Neman Sophia , Bedel Lauren E M , Mena Laurie A , Marr Emily H , Ross Michael G 
Published: June 2021

ObjectiveTo assess differences in rates of postpartum hospitalisations among homeless women compared with non-homeless women.DesignCross-sectional secondary analysis of readmissions and emergency department (ED) utilisation among postpartum women using hierarchical regression models adjusted for age, race/ethnicity, insurance type during delivery, delivery length of stay, maternal comorbidity index score, other pregnancy complications, neonatal complications, caesarean delivery, year fixed effect and a birth hospital random effect.SettingNew York statewide inpatient and emergency department databases (2009–2014).Participants82 820 and 1 026 965 postpartum homeless and non-homeless women, respectively.Main outcome measuresPostpartum readmissions (primary outcome) and postpartum ED visits (secondary outcome) within 6 weeks after discharge date from delivery hospitalisation.ResultsHomeless women had lower rates of both postpartum readmissions (risk-adjusted rates: 1.4% vs 1.6%; adjusted OR (aOR) 0.87, 95% CI 0.75 to 1.00, p=0.048) and ED visits than non-homeless women (risk-adjusted rates: 8.1% vs 9.5%; aOR 0.83, 95% CI 0.77 to 0.90, p<0.001). A sensitivity analysis stratifying the non-homeless population by income quartile revealed significantly lower hospitalisation rates of homeless women compared with housed women in the lowest income quartile. These results were surprising due to the trend of postpartum hospitalisation rates increasing as income levels decreased.ConclusionsTwo factors likely led to lower rates of hospital readmissions among homeless women. First, barriers including lack of transportation, payment or childcare could have impeded access to postpartum inpatient and emergency care. Second, given New York State’s extensive safety net, discharge planning such as respite and sober living housing may have provided access to outpatient care and quality of life, preventing adverse health events. Additional research using outpatient data and patient perspectives is needed to recognise how the factors affect postpartum health among homeless women. These findings could aid in lowering readmissions of the housed postpartum population.
Ticagrelor or Prasugrel in Patients With Acute Coronary Syndrome Undergoing Complex Percutaneous Coronary Intervention
Authors: Coughlan J.J. , Aytekin Alp , Ndrepepa Gjin , Schüpke Stefanie , Bernlochner Isabell , Mayer Katharina , Neumann Franz Josef , Menichelli Maurizio , Richardt Gert , Wöhrle Jochen , Witzenbichler Bernhard , Gewalt Senta , Xhepa Erion , Kufner Sebastian , Sager Hendrik B. , Joner Michael , Ibrahim Tareq , Fusaro Massimiliano , Laugwitz Karl Ludwig , Schunkert Heribert , Kastrati Adnan , Cassese Salvatore 
Published: June 2021

Background:
The comparative efficacy and safety of ticagrelor and prasugrel in patients with acute coronary syndrome undergoing complex percutaneous coronary intervention (PCI) has not been defined.

Methods:
This post hoc analysis included all patients with acute coronary syndrome treated with PCI and randomized to either ticagrelor or prasugrel in the ISAR-REACT 5 trial (Intracoronary Stenting and Antithrombotic Regimen: Rapid Early Action for Coronary Treatment). Complex PCI was defined as at least one of the following: multivessel PCI, ≥3 stents implanted, ≥3 lesions treated, and total stented length >60 mm. The primary efficacy end point was the composite of all-cause death, myocardial infarction, or stroke; the safety end point was Bleeding Academic Research Consortium types 3 to 5 bleeding. Outcomes were assessed out to 12 months after randomization.

Results:

Among the 3377 patients treated with PCI in the ISAR-REACT 5 trial, 1429 underwent complex PCI (ticagrelor, N=696 and prasugrel, N=733) and 1948 underwent noncomplex PCI (ticagrelor, N=980 and prasugrel, N=968). There was no interaction between PCI complexity, assignment to either ticagrelor or prasugrel, and the primary efficacy or safety end points (
P
for interaction: ≥0.13). In the complex PCI group, the primary efficacy end point (11.0% versus 9.2%, hazard ratio: 1.19 [0.85–1.66],
P
=0.303) and the safety end point (5.2% versus 6.1%, hazard ratio: 0.83 [0.53–1.31],
P
=0.419) were not statistically different in patients receiving either ticagrelor or prasugrel. In the noncomplex PCI group, the primary efficacy end point occurred more frequently in patients assigned to ticagrelor as compared to prasugrel (8.9% versus 5.5%, hazard ratio: 1.66 [1.18–2.34],
P
=0.004) without significant difference in terms of the safety end point (5.4% versus 4.1%, hazard ratio: 1.41 [0.92–2.17],
P
=0.110).

Conclusions:
In patients with acute coronary syndrome, PCI complexity does not influence the comparative efficacy and safety of ticagrelor and prasugrel. The observed comparable performance of ticagrelor and prasugrel in patients with acute coronary syndrome undergoing complex PCI requires further confirmation.

Registration:

URL:
https://www.clinicaltrials.gov
; Unique identifier: NCT01944800.
Characterisation of the complete mitochondrial genome of the insect-parasitic nematode Heterorhabditis bacteriophora: an idiosyncratic gene order and the presence of multiple long non-coding regions
Authors: Regeai Sassia Omar , Fitzpatrick David A. , Burnell Ann M. , Kakouli-Duarte Thomais 
Published: June 2021

Summary
We present here the complete mtDNA genome (mitogenome) of Heterorhabditis bacteriophora, an important biological control agent of soil-dwelling insect pests in agriculture and horticulture. This is the first description of a mitogenome for a member of the family Heterorhabditidae. The genome contains the typical chromadorean complement of 12 protein-coding genes, 22 tRNA genes and two rRNA genes. All genes are transcribed in the same direction and have a nucleotide composition high in A and T. For the entire genome, the nucleotide contents are 47.02% (T), 28.81% (A), 16.10% (G), 8.08% (C) and 75.83% (AT). Heterorhabditis bacteriophora has a unique, idiosyncratic gene arrangement. It differs from that of Caenorhabditis elegans in having a block of seven genes: trnQ-trnF-cytb-trnL1-cox3-trnT-nad4 translocated to a position between nad3 and nad5, as well as having a change in the position of the four tRNA block gene cluster, trnC-trnM-trnD-trnG, where trnC and trnM have switched places and trnD and trnG have translocated between nad4 and nad5 genes. The H. bacteriophora mitogenome is 18 128 bp long, and thus is ca 4 kb larger than the mitogenomes of most chromadoreans. This relatively large genome is due to the presence of five non-coding regions (NCR): NCR1 (114 bp), NCR2 (159 bp), NCR3 (498 bp), NCR4 (1917 bp) and NCR5 (2154 bp), which make up 26.7% of the genome. The NCR5 had the highest A + T content of 83.47% indicating that this region is the likely AT-rich control region. The complete 498 bp NCR3 sequence is duplicated in NCR4 and in NCR5 (the putative AT-rich control region). Such an organisation has not been reported previously in nematode mtDNA.
An Archaeological Investigation of Laloi East Molluscs Site at Kpone, Ghana
Authors: Biveridge Fritz 
Published: June 2021

Abstract
This article is a report of an archaeological investigation of the Laloi East Molluscs Site at Kpone, Greater Accra Region, Ghana. Although radiometric dates for this shell midden are currently unavailable, we believe that Laloi East dates to the Later Stone Age. If so, this site would be one of only two LSA sites in Ghana found and excavated along the coast rather than in the forested interior. This article examines shellfish exploitation and other major subsistence strategies of the population that settled the site in the past. The principal cultural materials recovered from the excavations comprised large quantities of molluscs’ remains belonging to a variety of species, other faunal remains, pottery, palm kernel nuts, charcoal, stone slabs, and lithic tools. The combined evidence indicates that molluscs’ exploitation was the principal subsistence strategy of the settlers, undertaken alongside hunting, trapping, herding and the gathering of edible botanical resources such as palm fruits.
The Role of Low-Level Flow Direction on Tropical Cyclone Intensity Changes in a Moderate-Sheared Environment
Authors: Lee Tsung-Yung , Wu Chun-Chieh , Rios-Berrios Rosimar 
Published: June 2021

AbstractThe impact of low-level flow (LLF) direction on the intensification of intense tropical cyclones under moderate deep-layer shear is investigated based on idealized numerical experiments. The background flow profiles are constructed by varying the LLF direction with the same moderate deep-layer shear. When the maximum surface wind speed of the simulation without background flow reaches 70 kt (36 m s−1), the background flow profiles are imposed. After a weakening period in the first 12 h, the members with upshear-left-pointing LLF (fast-intensifying group) intensify faster between 12 and 24 h than those members (slow-intensifying group) with downshear-right-pointing LLF. The fast-intensifying group experiences earlier development of inner-core structures after 12 h, such as potential vorticity below the midtroposphere, upper-level warm core, eyewall axisymmetrization, and radial moist entropy gradient, while the inner-core features of the slow-intensifying group remain relatively weak and asymmetric. The FI group experiences smaller tilt increase and stronger midlevel PV ring development. The upshear-left convection during 6–12 h is responsible for the earlier development of the inner core by reducing ventilation, providing axisymmetric heating, and benefiting the eyewall development. The LLF of the fast-intensifying group enhances surface heat fluxes in the downshear side, resulting in higher energy supply to the upshear-left convection from the boundary layer. In all, this study provides new insights on the impact of LLF direction on intense storms under moderate shear by modulating the surface heat fluxes and eyewall convection.