Line Spring Model and Its Applications to Part-Through Crack Problems in Plates and Shells

The line spring model is described and extended to cover the problem of interaction of multiple internal and surface cracks in plates and shells. The shape functions for various related crack geometries obtained from the plane strain solution and the results of some multiple crack problems are presented. The problems considered include coplanar surface cracks on the same or opposite sides of a plate, nonsymmetrically located coplanar internal elliptic cracks, and in a very limited way the surface and corner cracks in a plate of finite width and a surface crack in a cylindrical shell with fixed end

Axis formation in annual killifish: Nodal coordinates morphogenesis in absence of Huluwa prepatterning

Axis formation in fish and amphibians is initiated by a prepattern of maternal gene products in the blastula. The embryogenesis of annual killifish challenges prepatterning models because blastomeres disperse and then re-aggregate to form the germ layers and body axes. This dispersion-aggregation process prompts the question how axis determinants such as Huluwa and germ layer inducers such as Nodal function in annual killifish. Here we show in Nothobranchius furzeri that huluwa, the factor thought to break symmetry by stabilizing β-catenin, is a non-functional pseudogene. Nuclear β-catenin is not selectively stabilized on one side of the blastula but accumulates in cells forming the incipient aggregate. Inhibition of Nodal signaling blocks aggregation and disrupts coordinated cell migration, establishing a novel role for this signaling pathway. These results reveal a surprising departure from classic mechanisms of axis formation: canonical Huluwa-mediated prepatterning is dispensable and Nodal coordinates morphogenesis. One Sentence Summary Axis formation in annual killifish relies on Nodal to coordinate cell migration and is independent of Huluwa-mediated prepatterning

Eddy genesis and manipulation in plane laminar shear flow

Eddy formation and presence in a plane laminar shear flow configuration consisting of two infinitely long plates orientated parallel to each other is investigated theoretically. The upper plate, which is planar, drives the flow; the lower one has a sinusoidal profile and is fixed. The governing equations are solved via a full finite element formulation for the general case and semi-analytically at the Stokes flow limit. The effects of varying geometry (involving changes in the mean plate separation or the amplitude and wavelength of the lower plate) and inertia are explored separately. For Stokes flow and varying geometry, excellent agreement between the two methods of solution is found. Of particular interest with regard to the flow structure is the importance of the clearance that exists between the upper plate and the tops of the corrugations forming the lower one. When the clearance is large, an eddy is only present at sufficiently large amplitudes or small wavelengths. However, as the plate clearance is reduced, a critical value is found which triggers the formation of an eddy in an otherwise fully attached flow for any finite amplitude and arbitrarily large wavelength. This is a precursor to the primary eddy to be expected in the lid-driven cavity flow which is formed in the limit of zero clearance between the plates. The influence of the flow driving mechanism is assessed by comparison with corresponding solutions for the case of gravity-driven fluid films flowing over an undulating substrate. When inertia is present, the flow generally becomes asymmetrical. However, it is found that for large mean plate separations the flow local to the lower plate becomes effectively decoupled from the inertia dominated overlying flow if the wavelength of the lower plate is sufficiently small. In such cases the local flow retains its symmetry. A local Reynolds number based on the wavelength is shown to be useful in characterising these large-gap flows. As the mean plate separation is reduced, the form of the asymmetry caused by inertia changes, and becomes strongly dependent on the plate separation. For lower plate wavelengths which do not exhibit a cinematically induced secondary eddy, an inertially induced secondary eddy can be created if the mean plate separation is sufficiently small and the global Reynolds number sufficiently large

The Bathypelagic Biome of the Atlantic Ocean: Character and Ecological Discreteness of the Fish Fauna

Recent global synthetic analyses have revealed that marine taxonomic inventories are far from complete, nowhere more so than in the deep-pelagic ocean. At over a billion km3, it is the largest biome on Earth, yet only a tiny fraction of the biogeographic records include the bathypelagic fauna. This data gap served as the impetus for recent deepwater surveys, many of which have altered our perceptions of pelagic ecosystems. Here we examine data from four deep-pelagic (0-5000+ m) sampling programs in the Atlantic (60°N-25°S) in order to assess the character of bathypelagic fish communities with respect to faunal distinctiveness and ecological connectivity. Regions studied include the Gulf of Mexico, Sargasso 702 Sea, eastern North/South Atlantic, and mid-North Atlantic. Quantitative analyses give contrasting pictures with respect to faunal composition and ecosystem operation. The discreteness of the bathypelagic zone is exhibited faunistically by the suite of ―holobathypelagic‖ species found only below 1000 m, most of which are highly modified morphologically. Geometric abundance class analyses reveal that the character of relative species abundance distributions between the meso- and bathypelagic zones is fundamentally dissimilar; the former exhibit a much higher proportion of common species, while the latter exhibit a much higher percentage of rarer species. From a community energetics perspective, however, the bathy- and mesopelagic zones are highly interconnected. Approximately 70% of fish species collected below 1000 m are also found in the mesopelagic zone, and in the far North Atlantic, are also found in the epipelagial. These species comprised 66 to \u3e90% of individuals collected below 1000 m in the regions sampled. In the mid-North Atlantic, these species contribute to the unexpected water-column biomass maximum observed between 1500-2300 m. Thus, the ―transient‖ taxa (primarily mesopelagic migrators and spanner taxa) add considerably to the ichthyofaunal diversity of the world ocean below 1000 m, and appear to be the vectors that support the diverse array of holobathypelagic fishes whose taxonomic composition is dominated by piscivores. Data from the four regions studied suggests that classic pelagic biogeographic boundaries do not apply to bathypelagic realm, as shared species are the rule rather than the exception. Last, cumulative species curves suggest we are far from understanding the true complexity of the bathypelagic zone

Interactions in the 2x2x2 factorial randomised clinical STEPCARE trial and the potential effects on conclusions : a protocol for a simulation study

Background: Randomised clinical trials with a factorial design may assess the effects of multiple interventions in the same population. Factorial trials are carried out under the assumption that the trial interventions have no interactions on outcomes. Here, we present a protocol for a simulation study investigating the consequences of different levels of interactions between the trial interventions on outcomes for the future 2x2x2 factorial designed randomised clinical Sedation, TEmperature, and Pressure after Cardiac Arrest and REsuscitation (STEPCARE) trial in comatose patients after out-of-hospital cardiac arrest. Methods: By simulating a multisite trial with 50 sites and 3278 participants, and a presumed six-month all- cause mortality of 60% in the control population, we will investigate the validity of the trial results with different levels of interaction effects on the outcome. The primary simulation outcome of the study is the risks of type-1 and type-2 errors in the simulated scenarios, i.e. at what level of interaction is the desired alpha and beta level exceeded. When keeping the overall risk of type-1 errors Discussion: This protocol for a simulation study will inform the design of a 2x2x2 factorial randomised clinical trial of how potential interactions between the assessed interventions might affect conclusions. Protocolising this simulation study is important to ensure valid and unbiased results.Peer reviewe

Segmental Mean Square Displacement: Field-Cycling ¹H Relaxometry vs Neutron Scattering

© 2016 American Chemical Society.Proton (1H) field-cycling (FC) NMR relaxometry is applied to monitor the crossover in the segmental subdiffusion from the Rouse to the constrained Rouse regime in an entangled linear polymer melt. The method probes the dispersion of the spin-lattice relaxation rate R1(ω). Via Fourier transformation the segmental mean square displacement 〈r2(t)〉 is calculated from the intermolecular relaxation contribution R1inter(ω) to the total 1H spin-lattice relaxation dispersion R1(ω). As an example we chose poly(ethylene propylene) (M = 200k), and R1inter(ω) is singled out by performing an isotope dilution experiment. The 〈r2(t)〉 data obtained by FC NMR is directly compared to such of neutron scattering (NS) available from the literature. Because of different experimental time windows the NS data is converted to a reference temperature assuming frequency-temperature superposition. Absolute agreement is revealed between FC NMR and NS. The data on 〈r2(t)〉 confirm the predictions of the tube-reptation model; i.e., the crossover from Rouse regime to constraint Rouse regime is identified, and the tube diameter is estimated to d ≈ (4.6 ± 0.2) nm. Thus, 1H FC NMR has established itself as an alternative route to access subdiffusion

Dynamics of a paradigmatic linear polymer: A proton field-cycling NMR relaxometry study on poly(ethylene-propylene)

© 2016 American Chemical Society.The dynamics of melts of linear poly(ethylene-alt-propylene) (PEP) of different molar masses (M) is investigated by 1H field-cycling (FC) NMR relaxometry. Employing a commercial and a home-built relaxometer the spin-lattice relaxation rate R1(ω) is measured in the frequency range of 200 Hz to 30 MHz and the temperature range of 200-400 K. Transforming the FC NMR relaxation data to the susceptibility representation and applying frequency-temperature superposition, master curves for the dipolar correlation function CDD(t/τα) (containing intra- and intermolecular contributions) are constructed which extend up to six decades in amplitude and eight in time. Here, τα is the time scale of the structural (α-) relaxation, which is obtained over several decades. Comparison with previously reported FC data for polybutadiene (PB) discloses very similar CDD(t). Depending on M, all the five relaxation regimes of a polymer melt are covered: in addition to the α-process (0) and the terminal relaxation (IV), which are immanent to all liquids, three polymer-specific power-law regimes (Rouse, I; constraint Rouse, II; and reptation, III) are found, i.e. CDD(t) ∝ t-ϵ. The corresponding exponents (ϵI-III) are close to those predicted by the tube-reptation (TR) model for the segmental translation. In contrast to previous interpretation the intermolecular relaxation dominates CDD(t), in particular in regime II and beyond. The decomposition into intra- (mediated by segmental reorientation) and intermolecular relaxation (mediated by segmental translation) via isotope dilution experiments yields Cinter(t) = Ctrans(t) ∝ t-0.28±0.05 concerning PEP and Cinter(t) ∝ t-0.30±0.05 concerning PB for regime II (high-M limit). For the reorientational correlation function Cintra(t) = C2(t) ∝ t-0.50±0.05 (PEP) and C2(t) ∝ t-0.45±0.05 (PB) are obtained. These exponents ϵIIintra are at variance with ϵIITR = 0.25 predicted by the TR model. The fact that translation conforms to the TR model, while reorientation does not, now confirmed for the two polymers PEP and PB, challenges de Gennes' return-to-origin hypothesis which assumes strong translational-rotational coupling in the TR model

Organic selenium supplementation increased selenium concentrations in ewe and newborn lamb blood and in slaughter lamb meat compared to inorganic selenium supplementation

Background Selenium is part of the antioxidant defence system in animals and humans. The available selenium concentration in soil is low in many regions of the world. The purpose of this study was to evaluate the effect of organic versus inorganic selenium supplementation on selenium status of ewes, their lambs, and slaughter lambs. Methods Ewes on four organic farms were allocated five or six to 18 pens. The ewes were given either 20 mg/kg inorganic selenium as sodium selenite or organic selenium as selenized nonviable yeast supplementation for the two last months of pregnancy. Stipulated selenium concentrations in the rations were below 0.40 mg/kg dry matter. In addition 20 male lambs were given supplements from November until they were slaughtered in March. Silage, hay, concentrates, and individual ewe blood samples were taken before and after the mineral supplementation period, and blood samples were taken from the newborn lambs. Blood samples from ewes and lambs in the same pens were pooled. Muscle samples were taken from slaughter lambs in March. Selenium concentrations were determined by atomic absorption spectrometry with a hydride generator system. In the ANOVA model, selenium concentration was the continuous response variable, and selenium source and farm were the nominal effect variables. Two-sample t-test was used to compare selenium concentrations in muscle samples from the slaughtered lambs that received either organic or inorganic selenium supplements. Results In all ewe pens the whole blood selenium concentrations increased during the experimental period. In addition, ewe pens that received organic selenium had significantly higher whole blood selenium concentrations (mean 0.28 μg/g) than ewe pens that received inorganic selenium (mean 0.24 μg/g). Most prominent, however, was the difference in their lambs; whole blood mean selenium concentration in lambs from mothers that received organic selenium (mean 0.27 μg/g) was 30% higher than in lambs from mothers that received inorganic selenium (mean 0.21 μg/g). Slaughter lambs that received organic selenium had 50% higher meat selenium concentrations (mean 0.12 mg/kg wet weight) than lambs that received inorganic selenium (mean 0.08 mg/kg wet weight). Conclusion Organic selenium supplementation gave higher selenium concentration in ewe and newborn lamb blood and slaughter lamb meat than inorganic selenium supplementation

Rehabilitation Needs, Service Provision, and Costs in the First Year Following Traumatic Injuries: Protocol for a Prospective Cohort Study

Background: Traumatic injuries, defined as physical injuries with sudden onset, are a major public health problem worldwide. There is a paucity of knowledge regarding rehabilitation needs and service provision for patients with moderate and major trauma, even if rehabilitation research on a spectrum of specific injuries is available. Objective: This study aims to describe the prevalence of rehabilitation needs, the provided services, and functional outcomes across all age groups, levels of injury severity, and geographical regions in the first year after trauma. Direct and indirect costs of rehabilitation provision will also be assessed. The overarching aim is to better understand where to target future efforts. Methods: This is a population-based prospective follow-up study. It encompasses patients of all ages with moderate and severe acute traumatic injury (New Injury Severity Score >9) admitted to the regional trauma centers in southeastern and northern Norway over a 1-year period (2020). Sociodemographic and injury data will be collected. Upon hospital discharge, rehabilitation physicians estimate rehabilitation needs. Rehabilitation needs are assessed by the Rehabilitation Complexity Scale Extended–Trauma (RCS E–Trauma; specialized inpatient rehabilitation), Needs and Provision Complexity Scale (NPCS; community-based rehabilitation and health care service delivery), and Family Needs Questionnaire–Pediatric Version (FNQ-P). Patients, family caregivers, or both will complete questionnaires at 6- and 12-month follow-ups, which are supplemented by telephone interviews. Data on functioning and disability, mental health, health-related quality of life measured by the EuroQol Questionnaire (EQ-5D), and needs and provision of rehabilitation and health care services are collected by validated outcome measures. Unmet needs are represented by the discrepancies between the estimates of the RCS E–Trauma and NPCS at the time of a patient’s discharge and the rehabilitation services the patient has actually received. Formal service provision (including admission to inpatient- or outpatient-based rehabilitation), informal care, and associated costs will be collected. Results: The project was funded in December 2018 and approved by the Regional Committee for Medical and Health Research Ethics in October 2019. Inclusion of patients began at Oslo University Hospital on January 1, 2020, and at the University Hospital of North Norway on February 1, 2020. As of February 2021, we have enrolled 612 patients, and for 286 patients the 6-month follow-up has been completed. Papers will be drafted for publication throughout 2021 and 2022. Conclusions: This study will improve our understanding of existing service provision, the gaps between needs and services, and the associated costs for treating patients with moderate and major trauma. This may guide the improvement of rehabilitation and health care resource planning and allocation