bluuebunny/crossref_metadata_2025_split huggingface dataset:
Not just a methane source: Amazonian floodplain sediments harbour a high diversity of methanotrophs with different metabolic capabilities
Authors: Gontijo Júlia B. , Paula Fabiana S. , Venturini Andressa M. , Yoshiura Caio A. , Borges Clovis D. , Moura José Mauro S. , Bohannan Brendan J.M. , Nüsslein Klaus , Rodrigues Jorge L. Mazza , Tsai Siu M. 
Published: April 2021

AbstractThe Amazonian floodplain forests are dynamic ecosystems of great importance for the regional hydrological and biogeochemical cycles and function as a significant CH4 source contributing to the global carbon balance. Unique geochemical factors may drive the microbial community composition and, consequently, affect CH4 emissions across floodplain areas. Here, we report the in situ composition of CH4 cycling microbial communities in Amazonian floodplain sediments. We considered how abiotic factors may affect the microbial community composition and, more specifically, CH4 cycling groups. We collected sediment samples during wet and dry seasons from three different types of floodplain forests, along with upland forest soil samples, from the Eastern Amazon, Brazil. We used high‐resolution sequencing of archaeal and bacterial 16S rRNA genes combined with real‐time PCR to quantify Archaea and Bacteria, as well as key functional genes indicative of the presence of methanogenic (mcrA) and methanotrophic (pmoA) microorganisms. Methanogens were found to be present in high abundance in floodplain sediments, and they seem to resist the dramatic environmental changes between flooded and nonflooded conditions. Methanotrophs known to use different pathways to oxidise CH4 were detected, including anaerobic archaeal and bacterial taxa, indicating that a wide metabolic diversity may be harboured in this highly variable environment. The floodplain environmental variability, which is affected by the river origin, drives not only the sediment chemistry but also the composition of the microbial communities. These environmental changes seem also to affect the pools of methanotrophs occupying distinct niches. Understanding these shifts in the methanotrophic communities could improve our comprehension of the CH4 emissions in the region.
Development and validation of a novel microfluidic device for the manipulation of skeletal muscle microvascular blood flow in vivo
Authors: Russell McEvoy Gaylene M. , Shogan Hamza , Sové Richard J. , Fraser Graham M. 
Published: April 2021

AbstractObjectiveTo develop and validate a novel liquid microfluidic approach to deliver drugs to microscale regions of tissue while simultaneously allowing for visualization and quantification of microvascular blood flow.MethodsMicrofluidic devices were fabricated using soft lithographic techniques, molded in polydimethylsiloxane, and bound to a coverslip with a 600 × 300 μm micro‐outlet. Sprague‐Dawley rats, anesthetized with pentobarbital, were instrumented to monitor systemic parameters. The extensor digitorum longus muscle was dissected, externalized, and reflected across the device mounted on the stage of an inverted microscope. Doses (10−8 to 10−3 M) of adenosine triphosphate (ATP), acetylcholine, and phenylephrine (PE) were administered to the muscle via perfusion through the device. Microvascular blood flow directly overlying the micro‐outlet was recorded at multiple focal depths. Red blood cell (RBC) velocity, supply rate, and hematocrit were measured from recordings.ResultsATP significantly increased RBC velocity and supply rate. Increasing concentrations of PE caused a decrease in RBC velocity and supply rate. Perfusion changes were restricted to areas directly overlying the micro‐outlet and within 500 μm.ConclusionsThis novel microfluidic device allows for a controlled delivery of dissolved substances to constrained regions of microvasculature while simultaneously allowing for visualization and measurement of blood flow within discrete vessels and networks.
Evaluating the current condition of a threatened marine mammal population: Estimating northern sea otter (Enhydra lutris kenyoni) abundance in southwest Alaska
Authors: Beatty William S. , St. Martin Michelle , Wilson Ryan R. 
Published: April 2021

AbstractWe estimated density and abundance of the threatened southwest Alaska distinct population segment of northern sea otters (Enhydra lutris kenyoni) in two management units. We conducted aerial surveys in Bristol Bay and South Alaska Peninsula management units in 2016, and modeled sea otter density and abundance with Bayesian hierarchical distance sampling models and spatial environmental covariates (depth, distance to shore, depth × distance to shore). Spatial environmental covariates substantially impacted sea otter group density in both management units, but effects sizes differed between the two management units. Abundance (9,733 otters, 95% CrI 6,412–17,819) and density (0.82 otters/km2, 95% CrI 0.54–1.49) estimates for Bristol Bay indicated a moderate population size. In contrast, abundance (546 otters, 95% CrI 322–879) and density (0.06 otters/km2, 95% CrI 0.03–0.09) estimates indicated a relatively low population size in South Alaska Peninsula. Overall, our results highlight the importance of accounting for the detection process in monitoring at‐risk species to reduce the uncertainty associated with making conclusions about population declines.
Comparison of perceptions and barriers to mobilization in critical care: A comparison of nursing staff and physiotherapists—A single‐site service evaluation
Authors: Lewis Megan , Cumming Luke , Twose Paul 
Published: April 2021

AbstractBackgroundMobilization is a key component in the recovery of those admitted to critical care. However, previous research has demonstrated challenges in the implementation of mobilization within critical care, including staff knowledge, attitudes, and behaviours.AimThe aim of the current study was to explore the perceived barriers and limitations to mobilization from the perspective of nursing staff, and to compare these with physiotherapists.Study DesignSingle‐site service evaluation utilizing the patient mobilizations attitudes and beliefs survey for ICU and locally developed barriers to rehabilitation questionnaire.ResultsAbout 135 participants (126 nurses and 9 physiotherapists) were invited to anonymously complete the questionnaires (either paper or electronic), with a response rate of 73.0% (n = 92) for nursing staff and 100% for physiotherapists. Nursing staff reported significantly higher perceived barriers to rehabilitation on both questionnaires when compared with physiotherapy staff, which was not associated with years of experience within critical care. Behavioural barriers were most frequent in both professions which included items such as time availability and presence of perceived contra‐indications to mobilization.ConclusionNursing staff reported greater perceived barriers to rehabilitation when compared with physiotherapists. Further quality improvement projects are now required to reduce these barriers and assist the implementation of mobilization as part of the rehabilitation process.Relevance to Clinical PracticeRehabilitation is an essential element of practice within critical care. Understanding the system, local and personal barriers will allow for improvement projects to enhance the delivery of care and improve clinical outcomes.
Adherence to the CONSORT statement and extension for nonpharmacological treatments in randomized controlled trials of bariatric surgery: A systematic survey
Authors: Liu Meilu , Chen Jianrong , Wu Qingni , Zhu Weifeng , Zhou Xu 
Published: April 2021

SummaryReporting is critical for establishing the value of randomized controlled trials (RCTs). This study evaluated the adherence of bariatric surgery RCT reporting to the CONsolidated Standards Of Reporting Trials (CONSORT) statement 2010 and its 2017 extension for non‐pharmacologic treatments (NPT extension). We identified all RCTs comparing bariatric surgery with conservational therapy or alternative bariatric surgery up to June 30, 2020. Reporting quality was assessed using criteria developed from the CONSORT statement and the NPT extension and scored as a percentage. The factors associated with reporting quality were explored by univariate and multivariate analysis. In total, 102 RCTs of bariatric surgery were included. The median scores according to the CONSORT statement and NPT extension were 63.3 and 26.8 of a maximum possible 100, respectively. Two‐thirds of NPT extension items were reported in less than 25% of the RCTs. The median score improved over time for the CONSORT statement but not the NPT extension. A higher CONSORT score was associated with publication in core clinical journals, protocol registration, and funding. No factors associated with the NPT extension score were identified. Substantial efforts are warranted from authors, journals, registration platforms, and funders to overcome the flaws in the reporting of bariatric surgery RCTs.
1984: A Love Letter
Authors: Dotson Kristie 
Published: April 2021

AbstractDear Kris,I know you will read this letter if it ever manages to get to you. You like reading.I’m not sure what you’ll think of it though. I just know I had to make this attempt to talk to you about the summer of 1984.There are some things you and I come to know in the summer of 1984 that will take us 35 years to learn to talk about. They were not an easy 35 years. And I want to help change that.
Phylogeny and divergence dating of the ladybird beetle tribe Coccinellini Latreille (Coleoptera: Coccinellidae: Coccinellinae)
Authors: Nattier Romain , Michel‐Salzat Alice , Almeida Lucia M. , Chifflet‐Belle Pascaline , Magro Alexandra , Salazar Karen , Kergoat Gael J. 
Published: April 2021

AbstractWe reconstruct a comprehensively sampled molecular phylogeny for the second most species‐rich tribe of the ladybird beetle family Coccinellidae, the charismatic Coccinellini. We analysed a dataset consisting of five nuclear and three mitochondrial gene fragments from 150 taxa to provide a detailed phylogeny and estimates of historical divergence times using Bayesian relaxed clocks and primary fossil calibrations and an assessment of the evolution of feeding habits. The results of phylogenetic analyses provide strong support for the monophyly of the tribe Coccinellini, highlight the existence of four major clades and most sampled Coccinellini genera (30 out of 34) were recovered monophyletic. Our dating analyses suggest an Early Cretaceous origin for Coccinellidae atca. 140 millions years ago (Ma) and a Late Cretaceous origin for the tribe Coccinellini atca. 83.8 Ma. Ancestral character state estimation of feeding habits highlights a high level of phylogenetic niche conservatism on aphids and indicates that the most common recent ancestor of Coccinellini likely also fed on aphids. Our reconstruction of feeding habits and assessment of the aphid fossil record suggests that the diversification of Coccinellini paralleled that of Aphididae, although with substantial variation in host‐breadth and the tendency for a few specialized lineages towards non‐aphid feeding.
Fatigue Under Combined Pulsating Stresses
Authors: Majors H. , Mills B. D. , MacGregor C. W. 
Published: April 2021

Abstract
A special combined stress pulsator is described which was used to subject thin-walled cylindrical tubes to various ratios of combined (in phase) pulsating stresses. The material investigated was annealed SAE-1020 steel. Stress ratios in both the (+, +) and the (+, −) quadrants were applied. In addition, tension tests and uniaxial completely reversed rotating bending fatigue tests were made in the axial and tangential directions to study the anisotropy of the material. The combined stress-fatigue tests agreed best with the distortion-energy theory of strength.
Press-Forging Thin Sections: Effect of Friction, Area, and Thickness on Pressures Required
Authors: Schroeder William , Webster D. A. 
Published: April 2021

Abstract
The application of press forging to parts with thin sections is desirable in many instances. It is generally recognized that in forging such parts, the pressure required may be very high. That this high pressure required is due to friction has been reported; however, very little specific information on the effects of friction, area, and thickness is available. The results of this analysis resemble, in some respects, those presented in an analysis of forces required in rolling by Nadai.
The Dynamic Response of a Simple Elastic System to Antisymmetric Forcing Functions Characteristic of Airplanes in Unsymmetric Landing Impact
Authors: Woodson Joseph B. 
Published: April 2021

Abstract
This paper presents an analysis of the dynamic response of an undamped mechanical system with one degree of freedom subjected to disturbances which are described by antisymmetric forcing functions. The analysis was undertaken to throw light on the effect on the vibration of the wings caused by unsymmetric landing impact of an airplane. Two types of disturbances are considered; a full-sine-wave pulse, and a pulse which is the difference between two overlapping half sine waves. The results are presented in the form of dynamic-response curves and dynamic-response-factor curves. The numerically greatest dynamic-response factors, approximately 3.24 and −3.26, resulted for a full-sine-wave pulse disturbance with a ratio of duration of impact to natural period, Ti/T ≅ 1.11. When Ti/T is in the neighborhood of 1, the first positive peak of dynamic response is numerically less than the negative and positive peaks which follow it. For much of the range, the positive and negative dynamic-response factors are numerically approximately equal. The analysis was confined to values of Ti/T between 0.33 and 12. As Ti/T increases without limit, the positive and negative dynamic-response factors tend to 1 and −1, respectively.
Relation of Experiments to Mathematical Theories of Plasticity
Authors: Drucker D. C. 
Published: April 2021

Abstract
Several classes of mathematical theories of plasticity for work-hardening materials are surveyed and their advantages, disadvantages, and agreement with experiment discussed. Consideration is given to the proper correlation of tests on thin-walled tubes subjected to tension, torsion, and internal pressure in fixed but arbitrary ratio. The continuing debate between octahedral-shearing-stress and maximum-shearing-stress criteria of plastic deformation is re-examined and the more general alternatives are restated. Through an analysis of Osgood’s experimental results, it is made apparent that the more general point of view is required for the best correlation. A series of experiments are outlined which make the distinction between the various criteria of loading or deformation very large instead of just a few per cent as in previous work. In the evaluation of present mathematical theories it is shown that incremental-strain theories avoid obvious drawbacks of the so-called deformation type of theory. The concept of isotropic work hardening, assumed in practically all stress-strain relations, is explored and generalized. Strong limitations indicated by the Bauschinger effect, which cannot appear properly in such theories, are pointed out.
Bending Vibration of a Rotating Blade Vibrating in the Plane of Rotation
Authors: Sutherland R. L. 
Published: April 2021

Abstract
An analysis is developed for the uncoupled bending vibration of a rotating blade which is vibrating in the plane of rotation. The numerical method used permits the determination of any mode of vibration by a series of tabular calculations. Expressions are found for relative amplitudes of deflection, moment, and shear along the blade. A wedge-shaped steel blade is taken as an example, and the natural frequency and relative amplitudes of deflections, moments, and shears are found for: (a) non-rotating vibration; (b) vibration perpendicular to the plane of rotation; and (c) vibration in the plane of rotation, using for (a) and (b) the analysis developed by Myklestad (1).
Beam-Vibration Analysis With the Electric-Analog Computer
Authors: McCann G. D. , MacNeal R. H. 
Published: April 2021

Abstract
The authors have developed a true dynamic analogy which has been used with the Cal Tech electric-analog computer for the rapid and accurate solution of both steady-state and transient beam problems. This analogy has been found well suited to the study of beams having several coupled degrees of freedom, including torsion, simple bending, and bending in a plane. Damping and effects such as rotary inertia may be handled readily. The analogy may also be used in the study of systems involving combined beams and “lumped-constant” elements.
Introduction to the Comprex
Authors: Barry F. W. 
Published: April 2021

Abstract
This paper describes the construction and operation of a comprex, or pressure exchanger, together with its application to a gas-turbine cycle. A simple analysis is also developed, which is intended to indicate the performance characteristics of a comprex. This analysis shows that the pressure ratio, relative gas flow, and the ratio of the temperature of the leaving gas to that of the entering air are all functions of scavenging velocity and of the nature of the compression and expansion processes (as is shown graphically). Some irreversibility is found to be essential to the useful operation of a comprex. Finally, formulas for the major dimensions of a comprex are presented.
Holzer Method for Forced-Damped Torsional Vibrations
Authors: Spaetgens T. W. 
Published: April 2021

Abstract
The forced and resonant-vibration characteristics of a torsional system are easily enough determined by the well-known Holzer methods, in the case where the only major damping influences available in the system are those of the prime-mover itself, or of the propeller, in the case of a propeller-propulsion system. Where a damper exists within the system, the classic solution confines itself to the determination of the resonant-vibration characteristics under optimum damping conditions, and utilizes the principle of energy balance in conjunction with an equivalent system. The problem of forced vibration in a system having a damper is not susceptible, however, to such simple treatment regardless of whether or not the damping is optimum. This paper outlines an exact method, whereby both the forced- and the resonant-vibration characteristics of a viscously damped system may be calculated for any existing damping condition, optimum or otherwise, and which utilizes the ever-popular Holzer form.
On Plastic Flow and Vibrations
Authors: Thorne C. J. 
Published: April 2021

Abstract
A general solution is given for the behavior in the linear case of a mechanical model proposed and used by Henry Eyring and others. Four examples are worked in detail. In particular, the steady-state solution for the deflection in periodic vibrations is given in terms of the material constants for any frequency. The transients are given in detail for the three possible cases and inequalities are given to determine which case a particular problem is.
Flow of Heated Gases
Authors: Thompson A. S. 
Published: April 2021

Abstract
The purpose of this investigation was to find a convenient method for correlating the variables involved in the transfer of heat from the wall of a passage to a gas moving at high velocity in the passage. A graphical design method has been developed, using the Reynolds analogy between heat transfer and friction, for one-dimensional flow in a passage of variable area, and with variable wall temperature.
Some Experiments on the Interaction of Shock Waves With Boundary Layers on a Flat Plate
Authors: Barry F. W. , Shapiro A. H. , Neumann E. P. 
Published: April 2021

Abstract
Experimental results are presented in the form of schlieren and interferometer photographs showing the interaction of oblique shocks with laminar and turbulent boundary layers on a flat plate in a supersonic stream. The effects of variations in shock intensity and boundary-layer thickness were studied through a Mach number range of 2.0 to 2.5. A greater variety of shock boundary-layer interactions was discovered than had hitherto been suspected. The nature of the interaction was found not to be solely dependent upon whether the boundary layer is laminar or turbulent. A laminar layer proved to be more greatly affected by an incident oblique shock than a turbulent layer. With relatively intense shocks the boundary layer was influenced far upstream of the point of incidence. Injection of a high-speed air stream into a turbulent boundary layer altered significantly the manner of reflection of an incident shock.
On One-Term Approximations of Forced Nonharmonic Vibrations
Authors: Schwesinger G. 
Published: April 2021

Abstract
Steady forced vibrations of harmonically excited nonlinear systems deviate from a sinusoidal wave form, the magnitude of the deviation depending upon the frequency of the exciting force and the nature of the system concerned. Approximations by simple harmonic solutions suggested so far are either restricted to special vibration problems or generally fail to provide the desired accuracy without giving account of the errors committed. An improved general method is proposed and demonstrated, yielding the best accuracy attainable with harmonic solutions. This method, furthermore, gives the approximate root mean square of the error and thus allows for establishing dependable limits for its applicability.
Bending Vibrations of a Pipe Line Containing Flowing Fluid
Authors: Ashley Holt , Haviland George 
Published: April 2021

Abstract
Free vibrations and forced motions due to cross winds may both create important problems in the design of pipe lines supported above ground. An analytic investigation, based on simple beam theory, shows that the flow of fluid in such a pipe line produces marked damping tendencies and thus may reduce the severity of loading encountered. The time dependence of the fundamental mode of a simply supported pipe line is calculated for a number of mass-flow rates, the damping being observed to increase rapidly and the frequency to remain nearly constant over the practically important range. A method is outlined for studying forced vibration, higher modes, and other end conditions. Finally the problem is discussed in terms of traveling waves on an “infinite” unsupported pipe line.
Thermoelastic Stress Around a Cylindrical Inclusion of Elliptic Cross Section
Authors: Mindlin Raymond D. , Cooper Hilda L. 
Published: April 2021

Abstract
The two-dimensional equations of thermoelasticity are solved for the case of a uniform temperature change of an infinite medium containing a cylindrical inclusion of elliptic cross section. The problem is treated as one of plane strain in elliptic co-ordinates, and the solution is given in closed form. Formulas and curves are given for the maximum values of various components of stress at the interface between the inclusion and the surrounding medium.
Torsion of a Circular Shaft With a Number of Longitudinal Notches
Authors: Ōkubo H. 
Published: April 2021

Abstract
The object of this paper is to find a solution for the torsion problem of a circular shaft with a number of longitudinal semicircular notches. By using elementary functions the author has been able to simplify the numerical calculations in contrast to previous work in similar cases by other writers.