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Background and objectives: There are very limited data on the rate of urinary tract infections (UTI), bacteremia, and meningitis in preterm infants with fever. Many of the studies on the incidence of these infections excluded preterm infants. This study compared the rate of these infections in preterm infants born at 32-36 weeks to term infants born at 37-42 weeks. Methods: A multicenter observational cohort study was conducted to evaluate rates of UTI, bacteremia, and meningitis in term and preterm infants 8-60 days of age with a diagnosis of fever from 2016 through 2022 using encounter data from children's hospitals in the Pediatric Health Information System. Results: There were 19 507 total febrile infants identified, of which 2162 were preterm and 17 345 were term. Preterm infants had a lower rate of UTI than term infants (1.8% confidence interval [CI] [1.3-2.5] vs 3.0% CI [2.7-3.2], P = .001). Preterm and term infants did not have statistically different rates of bacteremia (1.5% CI [1.3-1.7] vs 1.2% CI [0.8-1.8], P = .44) or meningitis (0.16% CI [0.1-0.2] vs 0.05% CI [0-0.2], P = .36). Conclusions: There was no difference in the rate of bacteremia or meningitis between term and preterm infants in a large multicenter cohort of febrile infants. Preterm infants had a lower rate of UTI than term infants. This is the first multicenter study to compare UTI, bacteremia, and meningitis between term and preterm febrile infants. [ABSTRACT FROM AUTHOR]

In natural environments, fluid density and viscosity can be affected by spatial and temporal variations of solute concentration, for example, due to saltwater intrusion in coastal aquifers, leachate infiltration from waste disposal sites, and upconing of saline water from deep aquifers. Potentially unstable situations may arise in which a dense fluid overlies a less dense fluid. This situation can produce instabilities manifested by dense plume fingers moving vertically downwards counterbalanced by vertical upward flow of the less dense fluid. The resulting free convection increases solute transport rates over large distances and times relative to constant-density flow. Unstable brine flow is further complicated if the porous medium is variably saturated. The results from a laboratory experiment of variably saturated variable-density flow and solute transport from Simmons et al. (2002) are used as the physical basis to define a new mathematical benchmark. This benchmark aims at realistically reproducing the experimental fingering patterns. Random hydraulic conductivity fields were used in the simulations as a numerical perturbation method to realistically mimic the observed dense plume fingering. The HydroGeoSphere code coupled with PEST are used to calibrate the parameter set that defines the benchmark. A grid convergence analysis is performed to obtain the adequate spatial and temporal discretizations. The new mathematical benchmark is useful for model comparison and testing of variably saturated variable-density flow in porous media. Simmons CT, Pierini ML, Hutson JL (2002) Laboratory investigation of variable-density flow and solute transport in unsaturated–saturated porous media. Transp Porous Media. 47(2): 215–244, 10.1023/A:1015568724369. [ABSTRACT FROM AUTHOR]

4 Subregular linguistics for empirical analysis The previous two sections show that subregular linguistics is a much more empirical enterprise than is common for work rooted in formal grammar. Avcu & Rhodes discuss how formal grammar in general and subregular linguistics in particular enable researchers to connect the findings of theoretical linguistics to questions of psycho- and neurolinguistics, for example via artificial language learning experiments. In my target paper I Subregular linguistics: Bridging theoretical linguistics and formal grammar i I argued that theoretical linguistics and formal grammar, despite major differences in methodology, have a lot to offer to each other, and that the recently emerged subfield of I subregular linguistics i provides a conduit for knowledge transfer between the two. At the very heart of subregular linguistics as an empirical enterprise at the intersection of theoretical linguistics and formal grammar are two claims. A lot more could be said here about specific methodological points: why using the term I stipulative i (Chaves & Putnam p. 222) is a category mistake when talking about formal complexity results, how subregular linguistics engages with I-language and not E-language ([8]), how formal grammar has ways to quantify the trade-off between expressive adequacy and descriptive elegance ([38]), or why subregular linguistics would be an insightful enterprise even if some patterns may not be subregular at all. [Extracted from the article]

Subregular linguistics is a fairly new approach that seeks a deeper understanding of language by combining the rigor of formal grammar with the empirical sophistication of theoretical linguistics. The approach started in phonology but has since branched out to morphology and even syntax, unearthing unexpected parallels between these three domains of language. In this paper, I argue based on these results that subregular linguistics has a lot to offer to both fields. Subregular linguistics may be the ideal conduit for knowledge transfer between these two communities. [ABSTRACT FROM AUTHOR]

We argue that the collinear 4-point probe is unsuitable for measuring in-plane and through-plane electrical conductivity of graphite-polymer composite plates, and strongly recommend the 4-wire Kelvin measurement system with parallel block electrodes. Regarding the latter, we report the effect of applied pressure on the cell resistance and determine the offset resistance in the measurement system at 69 bar by extrapolating the cell resistance for a series of graphite monoliths of different thicknesses to zero thickness. We show that the fringe field effect increases the conductance of the cell, and ipso facto the conductance of the sample plate, when the cross-sectional area of the sample plate exceeds that of the block electrodes. An evaluation of the measurement uncertainty of the through-plane electrical conductivity, shows that the uncertainty of the through-plane resistance of the two gas diffusion layers (carbon fibre mat) and their interfacial contact resistance with the sample and electrodes whilst under compression (collectively referred to here as the 'offset resistance') is the major contributor. This article complements the US Fuel Cell Council's protocol 05-160 and the Keithley White Paper (No. 2399) in establishing an effective measurement procedure to enable a more reliable comparison of conductivity data. [Display omitted] • Collinear 4-point probe is shown to be unsuitable for graphite-polymer composites. • 4-wire Kelvin measurement system with block electrodes is shown to be viable. • Fringe field effect increases cell conductance when sample to probe area ratio >1. • Offset resistance found by extrapolating cell resistance to zero sample thickness. • Uncertainty of offset resistance is a major contributor to measurement uncertainty. [ABSTRACT FROM AUTHOR]

Histone methylation is required for the establishment and maintenance of gene expression patterns that determine cellular identity, and its perturbation often leads to aberrant development and disease. Recruitment of histone methyltransferases (HMTs) to gene regulatory elements (GREs) of developmental genes is important for the correct activation and silencing of these genes, but the drivers of this recruitment are largely unknown. Here we propose that lineage-instructive transcription factors (Lin-TFs) act as general recruiters of HMT complexes to cell type-specific GREs through protein–protein interactions. We also postulate that the specificity of these interactions is dictated by Lin-TF post-translational modifications (PTMs), which act as a 'transcription factor code' that can determine the directionality of cell fate decisions during differentiation and development. Lineage-instructive transcription factors (Lin-TFs) are able to drive cell fate changes by binding to sequence-specific motifs in gene regulatory elements (GREs). Histone methyltransferases (HMTs) decorate histones at different GREs in different cell types throughout development, regulating lineage-restricted gene activation and silencing. Several mechanisms for HMT recruitment to lineage-specific GREs have been described, but there is no clear consensus in the field. Time-resolved analysis shows that transcription factor binding often precedes histone modification changes in the neighboring nucleosomes. Lin-TFs can interact with HMT complexes. Lin-TFs are targets of a large number of modifying enzymes. Some of the resulting PTMs have been reported to modulate interactions of Lin-TFs with other proteins. [ABSTRACT FROM AUTHOR]

Pipe leakage from defect subsurface gravity sewer pipe networks potentially contaminates soil and groundwater. In recent times, an increasing number of numerical pipe leakage models incorporating pipe flow, saturated-unsaturated flow in the subsurface, and exchange fluxes from and to leaky pipes have been developed. Numerical benchmarks are required in order to demonstrate result accuracy of these models. The present technical note represents a novel numerical benchmark of the pipe leakage problem describing pipe water exfiltration into horizontal unsaturated-saturated soil. The present benchmark enables to test the accurate calculation of the spatial potential distribution in the soil, which is affected by the water level in the leaky pipe. The derivation of an analytical solution for stationary pipe water exfiltration into a horizontal aquifer and a conceptual model for the setup of a corresponding numerical model is shown. Results of the analytical model are reproduced using the numerical leakage model OGS-HE. [ABSTRACT FROM AUTHOR]

A significant volume of an aquifer along the coastline in the German Bight is salinized by seawater intrusion. The mean sea-level rise (MSLR) is expected to continue in the future due to global climatic change, subsequently degrading the fresh groundwater resources. To impede further salinization in the future, a solution is proposed based on weir construction in an existing canal hydraulically connected to the aquifer. The effect is twofold: (1) the elevated groundwater level can upgrade present fresh groundwater resources by shifting the saltwater–freshwater interface position further seaward, or by inhibiting its landward movement, and (2) the inland water level can be elevated, expanding surface water ponds. A fully coupled three-dimensional numerical surface-subsurface model (a modified HydroGeoSphere code) was used to simulate the effects of variable weir construction heights under different MSLR rates, and to quantify the gain of aquifer freshwater volume and loss of usable land due to surface ponding. Construction of a higher weir increases the desalinized aquifer volume and decreases the newly salinized aquifer volume under future MSLR. A minimum height of a weir was determined under a certain MSLR rate to maintain the present freshwater resource. Both weir construction and MSLR can cause the loss of land usage. Computed loss-gain ratio curves can be utilized to determine the optimal weir height, meeting the economic requirements of coastal land management under future MSLR. [ABSTRACT FROM AUTHOR]

• Stormwater pipe flow-soil-groundwater (GW) flow model applied on urban catchm. scale. • Impact of pipe leakage on urban GW is investigated under dry and rain conditions. • GW infiltr. in pipes may be as large as GW recharge and may reduce GW levels by meters. • Temporal distribution of a rain event has no effect on pipe leakage. In urban stormwater pipe networks, pipe leakage may lead to reduction of groundwater recharge, to significant reduction of groundwater levels, and to subsurface contamination. In the present study, stormwater pipe leakage is simulated in a case study representing an urban catchment using the coupled groundwater-pipe network flow model OGS-HE. This model includes pipe flow, variably saturated subsurface flow and exchange fluxes to and from leaky pipes. The study area is a typical northern German urban catchment with a stormwater pipe network which is located partly below and above groundwater. The successful calibration of a groundwater model is shown. Based on the calibrated groundwater model, stormwater pipe leakage for pipe networks of different ages and different pipe defect sizes is investigated for dry-weather flow conditions and rainfall conditions. It is shown that standard defects with a size of 10 - 4 m2 per m pipe can result in a groundwater infiltration into the leaky pipe network, which is in the order of annual groundwater recharge. The same standard defect size leads to a reduction of local groundwater levels by several meters. Rain events of increasing return period reduce groundwater infiltration into leaky pipes and increase stormwater exfiltration from leaky pipes, while the temporal distribution of a rain event has no effect on stormwater leakage. [ABSTRACT FROM AUTHOR]

Highlights • Introduction of Lagrangean particle based transport of contaminants. • Transport path prediction of point source pollution in surface water and sewer system. • Pollution storage on surface is an important factor to contaminant dynamics. • Variation of pollutant injection time or location results in different contamination pattern. Abstract A Lagrangean particle based transport model is introduced to calculate the potential contamination paths of solutes in drainage water in an urban area during a pluvial flood event. The necessity to capture the complexity of a surface runoff model and the coupling of pipe and surface are investigated. Results show that fully coupled hydrodynamic models are needed for a good representation of transport paths and breakthrough curves of contaminant concentration in drainage water. An analysis for time variation of a single location spill event is performed that shows a high variability in solute spreading depending on the spill relative to the rainfall characteristics. [ABSTRACT FROM AUTHOR]

We present the design for a double-sided cooling of a thin-disk laser crystal using transparent, convex-shaped heat spreaders. The thermal contact between laser crystal and heat spreaders is established without bonding by solely applying an axial compressive force. A model of the contact behavior taking into account the deformation of the surfaces of the heat spreaders due to bending under mechanical loading is presented. The scope and accuracy of the modeling is verified by numerical simulations using the finite-element method. Based on the modeling, an exemplary design of the heat spreader which has been used for the first experimental demonstration of this concept is carried out. Based on the model, an almost ideal scalability of the heat transfer coefficient is predicted. [ABSTRACT FROM AUTHOR]

The article discusses implications of the Court of Justice of the European Union (CJEU's) Coty judment for vertical online restrictions. It mentions that the European Union (EU) competition law principles that apply to selective distribution systems have been enforced primarily by national competition authorities since the 2004 decentralization of EU competition law enforcement.

In urban water pipe networks, pipe leakage may lead to subsurface contamination or to reduced waste water treatment efficiency. The quantification of pipe leakage is challenging due to inaccessibility and unknown hydraulic properties of the soil. A novel physically-based model for three-dimensional numerical simulation of pipe leakage in variably saturated soil is presented. We describe the newly implemented coupling between the pipe flow simulator HYSTEM-EXTRAN and the groundwater flow simulator OpenGeoSys and its validation. We further describe a novel upscaling of leakage using transfer functions derived from numerical simulations. This upscaling enables the simulation of numerous pipe defects with the benefit of reduced computation times. Finally, we investigate the response of leakage to different time-dependent pipe flow events and conclude that larger pipe flow volume and duration lead to larger leakage while the peak position in time has a small effect on leakage. [ABSTRACT FROM AUTHOR]

Application of numerical models is a common method to assess groundwater resources. The versatility of these models allows consideration of different levels of complexity, but the accuracy of the outcomes hinges upon a proper description of the system behaviour. In seawater intrusion assessment, the implementation of the sea-side boundary condition is of particular importance. We evaluate the influence of the slope of the sea-side boundary on the simulation results of seawater intrusion in a freshwater aquifer by employing a series of slope variations together with a sensitivity analysis by varying additional sensitive parameters (freshwater inflow and longitudinal and transverse dispersivities). Model results reveal a multi-dimensional dependence of the investigated variables with an increasing relevance of the sea-side boundary slope for seawater intrusion (decrease of up to 32%), submarine groundwater discharge zone (reduction of up to 55%), and turnover times (increase of up to 730%) with increasing freshwater inflow or dispersivity values. [ABSTRACT FROM AUTHOR]

This study investigates free thermal convection in heterogeneous porous media and its dependency on grid discretization. Heterogeneous hydraulic conductivity fields are described with a geostatistical approach. Numerical experiments are carried out with the heterogeneous thermal Elder problem. Results are evaluated qualitatively and quantitatively. Key results show that (1) grid convergence for thermal variable-density flow simulations in heterogeneous porous media can be achieved, (2) the degree and structure of a heterogeneous hydraulic conductivity field significantly affect thermal convective flow patterns, (3) steady-state heat distribution depends on the hydraulic conductivity field rather than on thermal conductivity, (4) more variant log hydraulic conductivity fields result in an increase of the heat flux, of the heat stored, and of the upwelling length of thermal plume fingers, (5) an increase in the horizontal correlation length of the log hydraulic conductivity field leads to an increase of the heat stored and the upwelling length, but it does not affect the heat flux, and (6) an increase in the mean of the log hydraulic conductivity field leads to an increase of the heat flux, of the heat stored, and of the upwelling length. [ABSTRACT FROM AUTHOR]

Density-driven, haline free convection in fractured porous rock is studied in a 3-dimensional numerical model to evaluate the onset and interdependence of intra- and interfracture convection. When the rock matrix allows for solute diffusion, the most likely mode of convection in a regular fracture circuit is interfracture convection along the circuit such that regular fracture circuits can be modeled in a reduced dimensionality (2D) model. The critical Rayleigh number for the onset of interfracture convection in a regular fracture circuit is determined to be half of the critical Rayleigh number for convection in a single vertical fracture. In more complex fracture networks, vertical “dead-end fractures” and additional fracture intersections complicate convective patterns. Combined inter- and intrafracture convection is possible, such that convection is hard to predict. [ABSTRACT FROM AUTHOR]

Unstable density-driven groundwater flow and solute transport (i.e., free convection) leads to spatiotemporal variations in pressure. Specific storage ( So) indicates the capability of a confined aquifer to release or store groundwater associated with a pressure change. Although So is known to dampen pressure propagation, So has been implicitly assumed to have a negligible impact on the unstable free convective process in prior studies. This work explores the effect of So on both the classic onset criterion and the fingering process using numerical models. Results show that the classic onset criterion is applicable when So is smaller than 10-1 m-1. Results also demonstrate that So does not play a significant role in the free convective fingering process unless it is greater than 10-3 m-1. For most practical purposes in hydrogeology (large Rayleigh number and small So), the implicit assumption of small or zero So is appropriate. [ABSTRACT FROM AUTHOR]

Numerical simulations in porous media with complex geometries such as fracture networks require irregular meshes with a large number of nodes. Discrete fracture models solve the flow and transport equations with the common node approach. These equations are usually solved simultaneously using common nodes, which increases the computational time as the number of nodes increases. Moreover, the mesh element size at fracture-matrix interfaces need to be further refined, increasing the total number of nodes and computational cost. The main objective of this paper is to efficiently model fracture networks. Therefore we: (i) modify a mesh generator algorithm to generate high-quality meshes for fracture networks where mesh refinement close to the fractures is allowed and (ii) investigate the possibility of reducing the required simulation time by reducing the number of total nodes by removing some fractures from a fracture network. Using a two-dimensional simulation domain of a fractured porous medium under saturated conditions with variable-density flow, we consider 3 statistically equivalent fracture networks embedded in a porous medium containing 50 fractures each with constant aperture. A simplified fracture network is obtained by finding the shortest path in each cluster between the 1st type boundary condition for transport and minimum points in each cluster, where a cluster is defined as all interconnected fractures with at least one fracture intersecting the contaminant source boundary condition. We compare results in terms of penetration depth of the 0.50 isochlore and the contaminant mass. This simplification strategy reduces computational times by up to 36%, while keeping the generated error below 20% both for the penetration depth of the 0.50 isochlore and for the contaminant mass. A sensitivity analysis is performed whereby the free diffusion coefficient, the matrix freshwater permeability, the porosity and the maximum density are modified. Based on these results, the proposed simplification strategy can estimate the penetration depth and the solute mass inside the domain for a wide range of parameter values, saving up to 58% of the CPU time. [ABSTRACT FROM AUTHOR]

Climate change is expected to induce sea level rise in the German Bight, which is part of the North Sea, Germany. Climate change may also modify river discharge of the river Weser flowing into the German Bight, which will alter both pressure and salinity distributions in the river Weser estuary. To study the long-term interaction between sea level rise, discharge variations, a storm surge and coastal aquifer flow dynamics, a 3D seawater intrusion model was designed using the fully coupled surface–subsurface numerical model HydroGeoSphere. The model simulates the coastal aquifer as an integral system considering complexities such as variable-density flow, variably saturated flow, irregular boundary conditions, irregular land surface and anthropogenic structures (e.g., dyke, drainage canals, water gates). The simulated steady-state groundwater flow of the year 2009 is calibrated using PEST. In addition, four climate change scenarios are simulated based on the calibrated model: (i) sea level rise of 1 m, (ii) the salinity of the seaside boundary increases by 4 PSU (Practical Salinity Units), (iii) the salinity of the seaside boundary decreases by 12 PSU, and (iv) a storm surge with partial dyke failure. Under scenarios (i) and (iv), the salinized area expands several kilometers further inland during several years. Natural remediation can take up to 20 years. However, sudden short-term salinity changes in the river Weser estuary do not influence the salinized area in the coastal aquifer. The obtained results are useful for coastal engineering practices and drinking water resource management. [ABSTRACT FROM AUTHOR]

Flow under variable-density conditions is widespread, occurring in geothermal reservoirs, at waste disposal sites or due to saltwater intrusion. The migration of dense plumes typically results in the formation of vertical plume fingers which are known to be triggered by material heterogeneity or by variations in source concentration that causes the density variation. Using a numerical groundwater model, six perturbation methods are tested under saturated and unsaturated flow conditions to mimic heterogeneity and concentration variations on the pore scale in order to realistically generate dense fingers. A laboratory-scale sand tank experiment is numerically simulated, and the perturbation methods are evaluated by comparing plume fingers obtained from the laboratory experiment with numerically simulated fingers. Dense plume fingering for saturated flow can best be reproduced with a spatially random, time-constant perturbation of the solute source. For unsaturated flow, a spatially and temporally random noise of solute concentration or a random conductivity field adequately simulate plume fingering. [ABSTRACT FROM AUTHOR]

The effect of fracture network geometry on free convection in fractured rock is studied using numerical simulations. We examine the structural properties of fracture networks that control the onset and strength of free convection and the patterns of density-dependent flow. Applicability of the equivalent porous medium approach (EPM) is also tested, and recommendations are given, for which situations the EPM approach is valid. To date, the structural properties of fracture networks that determine free convective flow are examined only in few, predominantly simplified regular fracture networks. We consider fracture networks containing continuous, discontinuous, orthogonal and/or inclined discrete fractures embedded in a low-permeability rock matrix. The results indicate that bulk permeability is not adequate to infer the occurrence and magnitude of free convection in fractured rock. Fracture networks can inhibit or promote convection depending on the fracture network geometry. Continuous fracture circuits are the crucial geometrical feature of fracture networks, because large continuous fracture circuits with a large vertical extent promote convection. The likelihood of continuous fracture circuits and thus of free convection increases with increasing fracture density and fracture length, but individual fracture locations may result in great deviances in strength of convection between statistically equivalent fracture networks such that prediction remains subject to large uncertainty. [ABSTRACT FROM AUTHOR]

• Selection of an ensemble of dynamic velocities and water levels from a database of pre-calculated scenarios using a nearest neighbour approach. • Introduction and analysis of four metrics for precipitation pattern to be used as an indicator for similarity in the nearest neighbour approach. • Guidelines for finding significant locations for error analysis of an ensemble of pre-calculated dynamic velocities and water levels. • Transport path analysis of point source injection in surface water and sewer system flow to analyse the similarity of different velocity fields in an urban catchment. • Indication of the important role of the response time of a sewer system in a metric for similarity of rainfall patterns to predict the resulting velocities. Urban flood warning systems need fast response times between the rainfall forecast and the flood alarm. Flood forecasts from physically based numerical models usually need much computation time. Flood forecasts based on databases from previous events or pre-simulated events can speed up the process of decision making. This work introduces and compares four distance metrics for temporal rainfall patterns used in a nearest neighbour based forecast system for dynamic water levels and velocities during pluvial floods. The system uses a database of 960 pre-calculated flood events. The performance of each metric is evaluated by analysis of time-series of flow variables. For the error quantification,a procedure to find a small number of representative locations in an urban catchment is described. A new approach to quantify the similarity of dynamic flow fields is introduced, which makes use of particle transport tracking. The four distance metrics are tested on forecast for four exemplary pluvial flood events resulting from rainfall of durations between 15 and 50 min and return-periods between 10 and 100 years. The best metric is based on the temporal precipitation pattern and takes the response time of the drainage system into account. If the pattern has a very short duration, a simpler characterisation-metric can be used, which takes the total volume, peak intensity and peak position into account. [ABSTRACT FROM AUTHOR]

• Cut-off wall can prevent lateral and vertical seawater intrusion. • Cut-off wall does not slow down the post-inundation recovery of freshwater storage in early stage. • Cut-off wall slows down the average recovery in high permeability islands. Freshwater lenses (FWL) underneath islands are often unique freshwater resources. Constructing cut-off walls in coastal islands to increase the FWL size has been proposed and tested effective. Meanwhile, seawater inundation induced by ocean surges on low-lying islands can cause the vertical intrusion of saltwater and salinization of FWL. Constructing cut-off walls can influence the post-inundation recovery once the FWL is salinized during the inundation. This influence has not been investigated and considered when discussing the feasibility of cut-off walls. In this study, we numerically simulated an ocean-surge inundation on a 2D, vertically oriented island constructed with a cut-off wall, using a coupled surface–subsurface approach. We varied the aquifer permeability and the depth of the cut-off wall. The effect of the cut-off wall on FWL was quantitatively assessed in terms of FWL volume and flushing time. The results show that the cut-off wall can significantly increase the volume of FWL, confirming previous studies, especially when it is constructed in high-permeability (>10−10.5 m2) islands and deeper. In addition, the cut-off wall can significantly reduce seawater infiltration by up to 40% during the inundation. Therefore, the recovery tends to be accelerated in the early stage, and in islands of low & intermediate permeability. However, the average recovery in high-permeability islands can be slowed down, because the cut-off wall reclaims larger and deeper space that is harder for flushing. As a first attempt to assess the feasibility of the cut-off wall construction from the perspective of FWL recovery, our study is important for the management of freshwater on islands facing the risk of ocean-surge inundation. [ABSTRACT FROM AUTHOR]

A method for determining the complete higher-order scattering matrix of an acoustic discontinuity is developed. The method is demonstrated for a right-angled waveguide bend, and the magnitude and phase of the reflection and transmission coefficients are extracted precisely. The procedure is straightforward and based on the solutions to the Helmholtz equation by the finite element method (FEM). The consistency of the scattering coefficients found by this method is verified by their properties of symmetry, and their accuracy is established by the conservation of energy. The reliability of the new technique is further proved by means of an arbitrary sound source and by comparing the direct FEM response to the reflection matrix calculation. Some features of the scattering matrix as a function of frequency are surprising, such as the steps and reversion of the phase evolution or the complete loss of transmission of the incoming wave. The methodology detailed in this paper can be extended to other multiport junctions, such as T-junctions or size discontinuities in ducts. [ABSTRACT FROM AUTHOR]

Abstract: Coastal aquifers are complex hydrologic systems because many physical processes interact: (i) variably saturated flow, (ii) spatial–temporal fluid density variations, (iii) tidal fluctuations, (iv) storm surges overtopping dykes, and (v) surface runoff of storm water. The HydroGeoSphere model is used to numerically simulate coastal flow dynamics, assuming a fully coupled surface–subsurface approach, accounting for all processes listed above. The diffusive wave approximation of the St. Venant equation is used to describe surface flow. Surface flow and salt transport are fully coupled with subsurficial variably saturated, variable-density flow and salt transport through mathematical terms that represent exchange of fluid mass and solute mass, respectively. Tides and storm surges induce a time-variant head that is applied to nodes of the surface domain. The approach is applied to real cases of tide and storm surge events. Tide simulation results confirm the existence of a recirculating zone, forming beneath the upper part of the intertidal zone. By monitoring the exchange fluid flux rates through the beach, it was found that the major inflow to the aquifer takes place at the upper part of the intertidal zone, which explains the formation of the recirculating zone. The recirculating zone is forming particularly during rising tide. Results from a storm surge simulation show that plume fingers develop below the flooded land surface. Natural remediation by seaward flowing freshwater is relatively slow, such that reducing the salt concentration in the aquifer down to drinking water standards takes up to 10years. [Copyright &y& Elsevier]

The hematopoietic stem cell (HSC) compartment is heterogeneous, yet our understanding of the identities of different HSC subtypes is limited. Here we show that platelet integrin CD41 (aIIb), currently thought to only transiently mark fetal HSCs, is expressed on an adult HSC subtype that accumulates with age. CD41+ HSCs were largely quiescent and exhibited myeloerythroid and megakaryocyte gene priming, governed by Gata1, whereas CD41- HSCs were more proliferative and exhibited lymphoid gene priming. When isolated without the use of blocking antibodies, CD41+ HSCs possessed long-term repopulation capacity on serial transplantations and showed a marked myeloid bias compared with CD41-HSCs, which yielded a more lymphoid-biased progeny. CD41-knockout (KO) mice displayed multilineage hematopoietic defects coupled with decreased quiescence and survival of HSCs, suggesting that CD41 is functionally relevant for HSC maintenance and hematopoietic homeostasis. Transplantation experiments indicated that CD41-KO-associated defects are long-term transplantable, HSC-derived and, in part, mediated through the loss of platelet mass leading to decreases in HSC exposure to important platelet released cytokines, such as transforming growth factor β1. In summary, our data provide a novel marker to identify a myeloid-biased HSC subtype that becomes prevalent with age and highlights the dogma of HSC regulation by their progeny. [ABSTRACT FROM AUTHOR]

Abstract: The automatic non-iterative second-order time-stepping scheme based on the temporal truncation error proposed by Kavetski et al. [Kavetski D, Binning P, Sloan SW. Non-iterative time-stepping schemes with adaptive truncation error control for the solution of Richards equation. Water Resour Res 2002;38(10):1211, http://dx.doi.org/10.1029/2001WR000720.] is implemented into the code of the HydroGeoSphere model. This time-stepping scheme is applied for the first time to the low-Rayleigh-number thermal Elder problem of free convection in porous media [van Reeuwijk M, Mathias SA, Simmons CT, Ward JD. Insights from a pseudospectral approach to the Elder problem. Water Resour Res 2009;45:W04416, http://dx.doi.org/10.1029/2008WR007421.], and to the solutal [Shikaze SG, Sudicky EA, Schwartz FW. Density-dependent solute transport in discretely-fractured geological media: is prediction possible? J Contam Hydrol 1998;34:273–91] problem of free convection in fractured-porous media. Numerical simulations demonstrate that the proposed scheme efficiently limits the temporal truncation error to a user-defined tolerance by controlling the time-step size. The non-iterative second-order time-stepping scheme can be applied to (i) thermal and solutal variable-density flow problems, (ii) linear and non-linear density functions, and (iii) problems including porous and fractured-porous media. [Copyright &y& Elsevier]

Background and purpose Metaphyseal anchored short-stem hip implants were designed to improve load transmission and preserve femoral bone stock. Until now, only few outcome data have been available and migration studies are one of the few ways of obtaining data that are predictive of implant survival. We therefore evaluated a metaphyseal anchored short-stem hip implant by Ein Bild Roentgen Analyse femoral component analysis (EBRA-FCA). Patients and methods First, the EBRA-FCA method was validated for the short-stem hip implant. Then 80 of the first 100 consecutive implants were evaluated after at least 2 years. Clinical assessment was performed using the WOMAC and the UCLA score. Results After 2.7 (2.0-4.2), years none of the implants had been revised and by that time the stems had subsided by a mean of 0.7 mm (SD 1.8) (95% CI: 0.3-1.1). Of the 80 implants, 78 were stable after 2 years, with 74 being primary stable and 4 showing secondary stabilization after initial subsidence. Continuous migration was seen in only 2 patients. The clinical outcome showed good results with a mean WOMAC of 11 (SD 13) and a mean UCLA score of 7.3 (SD 2.0). [OK?] Interpretation The metaphyseal anchored short-stem hip implant showed good functional results and a high degree of stability after 2 years. The outcome is comparable to that of clinically proven conventional hip implants and if the results are confirmed by long-term studies, short-stem hip arthroplasty might be an alternative for young patients requiring hip replacement. [ABSTRACT FROM AUTHOR]

Motivation The compartmentalization of biochemical reactions, involved in the activation of gene expression in the eukaryotic nucleus, leads to the formation of membraneless bodies through liquid–liquid phase separation. These formations, called transcriptional condensates, appear to play important roles in gene regulation as they are assembled through the association of multiple enhancer regions in 3D genomic space. To date, we are still lacking efficient computational methodologies to identify the regions responsible for the formation of such condensates, based on genomic and conformational data. Results In this work, we present SEGCOND, a computational framework aiming to highlight genomic regions involved in the formation of transcriptional condensates. SEGCOND is flexible in combining multiple genomic datasets related to enhancer activity and chromatin accessibility, to perform a genome segmentation. It then uses this segmentation for the detection of highly transcriptionally active regions of the genome. At a final step, and through the integration of Hi-C data, it identifies regions of putative transcriptional condensates (PTCs) as genomic domains where multiple enhancer elements coalesce in 3D space. SEGCOND identifies a subset of enhancer segments with increased transcriptional activity. PTCs are also found to significantly overlap highly interconnected enhancer elements and super enhancers obtained through two independent approaches. Application of SEGCOND on data from a well-defined system of B-cell to macrophage transdifferentiation leads to the identification of previously unreported genes with a likely role in the process. Availability and implementation Source code and details for the implementation of SEGCOND is available at https://github.com/AntonisK95/SEGCOND Supplementary information Supplementary data are available at Bioinformatics online. [ABSTRACT FROM AUTHOR]

Abstract: Grid convergence in space and time of variable-density flow in fractured-porous rock is systematically assessed. Convergence of the flow simulation is attained using both uniform and adaptive time-stepping. This contrasts to variable-density flow in unfractured porous media where grid convergence variable-density flow problems is almost never achieved. At high discretization levels, the number of fingers in fractured-porous rock is no longer influenced by spatial–temporal grid discretization, which is not the case in unfractured porous media. However, similar to unfractured porous media, the number of fingers in fractured-porous media varies at low discretization levels. Simulated convective pattern and penetration depth of the dense plume in fractured rock depend more on spatial discretization than on temporal discretization. The appropriate spatial–temporal grid is then used to examine some aspects of mixed convection in fractured-porous rock, characterized by the mixed convection number M. The critical mixed convection number M c =46 represents the transition between forced and free convection in fractured porous media, which is much higher than M c =1 in unfractured porous media. Thus, for mixed convective flow problems, the value of M c is not a sufficient indicator to predict the convective mode (free convection–forced convection), and the presence of vertical fractures must be included in the prediction of convective flow modes. [Copyright &y& Elsevier]

Summary: The HydroGeoSphere model is further developed and used to investigate the effects of viscosity, capillarity and grid spacing on thermal variable-density flow. Under saturated and unsaturated flow conditions, the flow dynamics significantly depends on the viscosity assumption (constant vs. variable), where downwelling regions (constant viscosity) become upwelling regions (temperature-dependent variable viscosity). Capillarity does not change the location of downwelling and upwelling regions. Capillarity can significantly alter the flow dynamics in the way that the water table acts as a “lid” to flow, and it diverts a thermal plume laterally. Significance of capillarity increases with increasing soil moisture. Thermal convective flow is highly sensitive to spatial discretization. While the flow dynamics remains to be a function of grid level, spatial discretization Δx =Δz =1m appears to be appropriate to simulate unsaturated variable-density flow and heat transfer in porous media because estimated errors have asymptotically reached a minimum. [ABSTRACT FROM AUTHOR]

The ability to produce stem cells by induced pluripotency (iPS reprogramming) has rekindled an interest in earlier studies showing that transcription factors can directly convert specialized cells from one lineage to another. Lineage reprogramming has become a powerful tool to study cell fate choice during differentiation, akin to inducing mutations for the discovery of gene functions. The lessons learnt provide a rubric for how cells may be manipulated for therapeutic purposes. [ABSTRACT FROM AUTHOR]

Abstract: A test case has been developed for three-dimensional simulations of variable-density flow and solute transport in discretely-fractured porous media. The simulation domain is a low-permeability porous matrix cube containing a single non-planar fracture. The initial solute concentration is zero everywhere. A constant solute concentration is assigned to the top of the domain, which increases near-top fluid density and induces downward density-driven flow. The test case is therefore comparable to downwelling of a dense brine below a saline disposal basin or a waste repository. Numerous fingers and distinct convection cells develop early in the fracture but the fingers later coalesce and convection becomes less apparent. To help test other variable-density flow and transport models, results of the test case are presented both qualitatively (concentration contours and velocity fields) and quantitatively (penetration depth, mass flux, total mass stored, maximum fracture and matrix velocity). [Copyright &y& Elsevier]

This article examines the required spatial discretization perpendicular to the fracture-matrix interface (FMI) for numerical simulation of solute transport in discretely fractured porous media. The discrete-fracture, finite-element model HydroGeoSphere ( Therrien et al. 2005 ) and a discrete-fracture implementation of MT3DMS ( Zheng 1990 ) were used to model solute transport in a single fracture, and the results were compared to the analytical solution of Tang et al. (1981) . To match analytical results on the relatively short timescales simulated in this study, very fine grid spacing perpendicular to the FMI of the scale of the fracture aperture is necessary if advection and/or dispersion in the fracture is high compared to diffusion in the matrix. The requirement of such extremely fine spatial discretization has not been previously reported in the literature. In cases of high matrix diffusion, matching the analytical results is achieved with larger grid spacing at the FMI. Cases where matrix diffusion is lower can employ a larger grid multiplier moving away from the FMI. The very fine spatial discretization identified in this study for cases of low matrix diffusion may limit the applicability of numerical discrete-fracture models in such cases. [ABSTRACT FROM AUTHOR]

Recent research suggests that lymphoid progenitors in the bone marrow comprise a heterogeneous cell population. This population first loses megakaryocyte/erythroid, and then granulocyte/macrophage, potential before committing to lymphoid lineages. B and T cells can originate by way of different pathways that appear to be used with varying frequencies in the animal. In the bone marrow, B cell specification and commitment is driven by the concerted action of transcription factors and IL-7 signaling. In the thymus, multipotent progenitors become committed to the T-cell lineage through the action of Notch1. The activated intracellular form of Notch1 suppresses transcription factors that can instruct myeloid cell fates, thereby directly coupling extracellular signaling with changes in transcriptional networks. In conclusion, although a lot is known about B and T cell commitment, more work needs to be done to clarify the earliest steps in lymphoid specification. [Copyright &y& Elsevier]

Summary: A 3D numerical model has been developed to solve coupled fluid flow, heat and single-species reactive mass transport with variable fluid density and viscosity. We focus on a single reaction between quartz and its aqueous form silica. The fluid density and viscosity and the dissolution rate constant, equilibrium constant and activity coefficient are calculated as a function of the concentrations of major ions and temperature. Reaction and flow parameters, such as mineral surface area and permeability, are updated at the end of each time step with explicitly calculated reaction rates. Adaptive time stepping is used to increase or decrease the time step size according to the rate of temporal variation of the solution to prevent physically unrealistic results. The time step size depends on maximum changes in matrix porosity and/or fracture aperture. The model is verified against existing analytical solutions of heat transfer and reactive transport in fractured porous media. The complexity of the model formulation allows studying chemical reactions and variable-density flow in a more realistic way than done previously. The newly developed model has been used to simulate illustrative examples of coupled thermohaline flow and reactive transport in fractured porous media. Simulations indicate that thermohaline (double-diffusive) transport impacts both buoyancy-driven flow and chemical reactions. Hot zones correspond to upwelling and to quartz dissolution while in cooler zones, the plume sinks and silica precipitates. The silica concentration is inversely proportional to salinity in high-salinity regions and proportional to temperature in low-salinity regions. Density contrasts are generally small and fractures do not act like preferential pathways but contribute to transverse dispersion of the plume. Results of a long-term (100 years) simulation indicate that the coexistence of dissolution and precipitation leads to self-sealing of fractures. Salt mass fluxes through fractures decrease significantly due to major fracture aperture reduction in the precipitation zone. The system is the most sensitive to temperature because it impacts both the dissolution kinetics (Arrhenius equation) and the quartz solubility. The system is least sensitive to quartz surface area in the fracture because the volumetric fraction of a fracture is small compared to the volumetric fraction of the porous matrix. [Copyright &y& Elsevier]

Abstract: Numerical simulations of variable-density flow and solute transport have been conducted to investigate dense plume migration for various configurations of 2D fracture networks. For orthogonal fractures, simulations demonstrate that dispersive mixing in fractures with small aperture does not stabilize vertical plume migration in fractures with large aperture. Simulations in non-orthogonal 2D fracture networks indicate that convection cells form and that they overlap both the porous matrix and fractures. Thus, transport rates in convection cells depend on matrix and fracture flow properties. A series of simulations in statistically equivalent networks of fractures with irregular orientation show that the migration of a dense plume is highly sensitive to the geometry of the network. If fractures in a random network are connected equidistantly to the solute source, few equidistantly distributed fractures favor density-driven transport. On the other hand, numerous fractures have a stabilizing effect, especially if diffusive transport rates are high. A sensitivity analysis for a network with few equidistantly distributed fractures shows that low fracture aperture, low matrix permeability and high matrix porosity impede density-driven transport because these parameters reduce groundwater flow velocities in both the matrix and the fractures. Enhanced molecular diffusion slows down density-driven transport because it favors solute diffusion from the fractures into the low-permeability porous matrix where groundwater velocities are smaller. For the configurations tested, variable-density flow and solute transport are most sensitive to the permeability and porosity of the matrix, which are properties that can be determined more accurately than the geometry and hydraulic properties of the fracture network, which have a smaller impact on density-driven transport. [Copyright &y& Elsevier]

To investigate the physical mechanism of the saturation process in Cr4+ :YAG crystals we solved the three coupled rate equations which describe the saturable absorber. We experimentally verified this model using two lasers with nanosecond pulses and continuous-wave radiation. We used crystalline and ceramic Cr4+-doped YAG saturable absorbers with various initial transmissions. The ratio between the ground and the excited-state absorption cross section at 1064 nm was measured to be between 3.8 ± 0.2 and 4.7 ± 0.2 for crystalline and 3.6 ± 0.1 for ceramic Cr4+ :YAG. The ratio between the above named cross sections at 1047 nm was found to be 6.2 ± 0.2 for both crystalline and ceramic Cr4+ :YAG. With these results the ground-state and the excited-state absorption cross sections at 1047 nm were calculated to be (9.55 ± 0.01) × 10-19 cm2 and (1.54 ± 0.03) × 10-19 cm2, respectively. [ABSTRACT FROM AUTHOR]

Abstract: Variations in fluid density can greatly affect fluid flow and solute transport in the subsurface. Heterogeneities such as fractures play a major role for the migration of variable-density fluids. Earlier modeling studies of density effects in fractured media were restricted to orthogonal fracture networks, consisting of only vertical and horizontal fractures. The present study addresses the phenomenon of 3D variable-density flow and transport in fractured porous media, where fractures of an arbitrary incline can occur. A general formulation of the body force vector is derived, which accounts for variable-density flow and transport in fractures of any orientation. Simulation results are presented that show the verification of the new model formulation, for the porous matrix and for inclined fractures. Simulations of variable-density flow and solute transport are then conducted for a single fracture, embedded in a porous matrix. The simulations show that density-driven flow in the fracture causes convective flow within the porous matrix and that the high-permeability fracture acts as a barrier for convection. Other simulations were run to investigate the influence of fracture incline on plume migration. Finally, tabular data of the tracer breakthrough curve in the inclined fracture is given to facilitate the verification of other codes. [Copyright &y& Elsevier]

without adaptive optics high-power lasers suffer either from poor beam quality or limited power ranges. A laser can be forced to operate on its stability limit by self-adaptive overcompensation resulting in constant and good beam quality over a large power range. With this technique, the brightness of a Nd:YAG laser was increased by almost an order of magnitude despite highly aber-rated thermal lens in the laser rod. [ABSTRACT FROM AUTHOR]

Hematopoietic cells have been reported to convert into a number of non-hematopoietic cells types after transplantation/injury. Here, we have used a lineage tracing approach to determine whether hematopoietic plasticity is relevant for the normal development of hepatocytes and endothelial cells, both of which develop in close association with blood cells. Two mouse models were analyzed: vav ancestry mice, in which essentially all hematopoietic cells, including stem cells, irreversibly express yellow fluorescent protein (YFP); and lysozyme ancestry mice, in which all macrophages, as well as a small subset of all other non-myeloid hematopoietic cells, are labeled. Both lines were found to contain YFP+ hepatocytes at similar frequencies, indicating that macrophage to hepatocyte contributions occur in unperturbed mice. However, the YFP+ hepatocytes never formed clusters larger than three cells, suggesting a postnatal origin. In addition, the frequency of these cells was very low (∼1 in 75,000) and only increased two- to threefold after acute liver injury. Analysis of the two mouse models revealed no evidence for a hematopoietic origin of endothelial cells, showing that definitive HSCs do not function as hemangioblasts during normal development. Using endothelial cells and hepatocytes as paradigms, our study indicates that hematopoietic cells are tightly restricted in their differentiation potential during mouse embryo development and that hematopoietic plasticity plays at best a minor role in adult organ maintenance and regeneration. [ABSTRACT FROM AUTHOR]

A dielectric graded-phase mirror was developed to change the intensity distribution of the fundamental mode in an Nd:YAG laser resonator to a top-hat profile. A super-Gaussian mode of the sixth order was generated by means of a graded-phase mirror with a simple ring-shaped phase step on a spherical reflector. The depth of the ring on the mirror was 90 nm. The graded- phase mirror was manufactured with an ordinary vapor deposition technique using an appropriate mask. Laser experiments with CW and repetitively pulsed diode-laser pumping were performed and compared. Slope efficiencies up to 19% were achieved. The experimental results are in excellent agreement with the theory. [ABSTRACT FROM AUTHOR]

A consistent derivation of a system of vector coupled-mode (VCM) equations for parallel dielectric waveguides is presented and compared with earlier versions of the improved coupled-mode theory (ICMT). As a validity test, it is shown that the effectively scalar transverse electric and transverse magnetic (TM) coupled-mode (CM) equations are direct limits of our full VCM formulation. In particular, our formulation does not lead to the fundamental error found with earlier coupled-mode theories (CMTs) in a case of TM fields. Functional equations of our VCMT are consistent with Maxwell's equations and lead to higher precision. They can be applied to complicated arrays of strongly coupled parallel dielectric waveguides with true vectorial behavior. [ABSTRACT FROM AUTHOR]

Presents a self-adjusting compensation scheme for thermally induced lenses of high-power solid-state lasers. Significance of diode-pumped lasers to industrial applications; Requirements of the compensating element and its influence on resonator; Implications of the proposed compensating element and resonator model design for enhancing constant beam parameters.

Highlights the use of a rotating ball inlet in the design of an on-line matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS). Use of a capillary to deliver a matrix and analyte solution to the surface of a rotating ball; Preliminary results from flow injection analysis; Limitation of the MALDI-MS method; Improvements needed for the system.

We report on the characterization and first laser operation of ceramic Yb:LuScO3 in a thin-disk oscillator. The optical performance achieved with a ceramic Yb:LuScO3 disk is compared to the one obtained with an existing ceramic Yb:Lu2O3 disk for reference. The characterization covers the measurement of the fluorescence spectra, the fluorescence lifetimes, and nomarsky imaging. The investigation on the laser operation covers the measurement of resonator losses, output powers, and thermal behavior during continuous-wave operation in a multimode thin-disk oscillator. An average output power of 149 W and a slope efficiency of 51.8% were achieved with the ceramic Yb:LuScO3 disk which reached a maximum surface temperature of about 150 °C. At the same temperature level, a disk made of the already established ceramic Yb:Lu2O3 delivered 957 W of output power with a slope efficiency of 75.7%. [ABSTRACT FROM AUTHOR]