julilili42/papers huggingface dataset:
Longitudinal Data Analysis of Symptom Score Trajectories Using Linear Mixed Models in a Clinical Trial
2013-10-31

In clinical trials, longitudinal data are often analyzed using T-tests, anovas or ancovas instead of the more powerful linear mixed models. The purpose of this paper is to demonstrate how the more sophisticated linear mixed models according to the approach of Singer and Willett, which allows special insight into the behaviour of the data, can be used in clinical trials. Individual trajectories of PANNS-MNS Scores from a controlled clinical trial were used to demonstrate all the steps needed for an analysis of longitudinal data. The model is built step by step, model assumptions are checked, time-variant and time-invariant factors are included and the results are interpreted. The unique needs of a clinical trial, such as the calculation of effect sizes or of an appropriate sample size, are taken into account. Finally, a flow chart is presented that would serve as an instruction tool for the analysis of longitudinal data in clinical trials.
GRAVITATIONAL-REDSHIFT PROPORTIONAL SIZE INCREASE IN RINDLER METRIC
2013-10-31

The recently described gravitational-redshift proportional size change implicit in the Schwarzschild metric of general relativity and in the equivalence principle, is demonstrated geometrically in the Rindler metric. The result automatically carries over to general relativity (global constancy of c). Implications regarding terrestrial collision experiments, metrology, cosmology and unified physics are pointed out.
Reversal Learning and Associative Memory Impairments in a BACHD Rat Model for Huntington Disease
2013-11-01

Chorea and psychiatric symptoms are hallmarks of Huntington disease (HD), a neurodegenerative disorder, genetically characterized by the presence of expanded CAG repeats (>35) in the Huntingtin (HTT) gene. HD patients present psychiatric symptoms prior to the onset of motor symptoms and we recently found a similar emergence of non motor and motor deficits in BACHD rats carrying the human full length mutated HTT (97 CAG-CAA repeats). We evaluated cognitive performance in reversal learning and associative memory tests in different age cohorts of BACHD rats. Male wild type (WT) and transgenic (TG) rats between 2 and 12 months of age were tested. Learning and strategy shifting were assessed in a cross-maze test. Associative memory was evaluated in different fear conditioning paradigms (context, delay and trace). The possible confound of a fear conditioning phenotype by altered sensitivity to a 'painful' stimulus was assessed in a flinch-jump test. In the cross maze, 6 months old TG rats showed a mild impairment in reversal learning. In the fear conditioning tasks, 4, 6 and 12 months old TG rats showed a marked reduction in contextual fear conditioning. In addition, TG rats showed impaired delay conditioning (9 months) and trace fear conditioning (3 months). This phenotype was unlikely to be affected by a change in 'pain' sensitivity as WT and TG rats showed no difference in their threshold response in the flinch-jump test. Our results suggest that BACHD rats have a profound associative memory deficit and, possibly, a deficit in reversal learning as assessed in a cross maze task. The time course for the emergence of these symptoms (i.e., before the occurrence of motor symptoms) in this rat model for HD appears similar to the time course in patients. These data suggest that BACHD rats may be a useful model for preclinical drug discovery.
Effect of r1 and r2 relaxivity of gadolinium‐based contrast agents on the T1‐weighted MR signal at increasing magnetic field strengths
2013-11-01

Most contrast agents for magnetic respnance imaging (MRI) are gadolinium‐based T 1 shortening agents. At increasing magnetic field strengths their r 1 relaxivity tends to decrease while the r 2 relaxivity increases. In parallel, at high fields the tissue T 1 times increase and may mitigate the loss in contrast enhancement in T 1 ‐weighted images owing to improved background suppression. In the present work we explored the MR signal for T 1 ‐weighted spoiled gradient echo MRI sequences by simulations at three magnetic field strengths: 3, 7 and 9.4 T. The maximal available contrast enhancement (maxCE) was evaluated in absolute terms with the purpose of assessing how much of the full, underlying magnetization can be exploited, for a wide range of compound properties ( r 1 , 2–45 m m −1 s −1 ; r 2 / r 1 , 1.2–30). Despite the theoretically predicted loss in r 1 relaxivity at high fields, the same maxCE can be obtained as at low fields if the r 2 / r 1 ratio remains unchanged, albeit at the cost of a longer sequence repetition time and 1.5–2 times higher administered doses. For a fixed maximum tissue concentration, there is an optimum field‐dependent value for the r 1 relaxivity that yields the greatest maxCE. If the upper bound for the gadolinium concentration is 2 m m , the greatest maxCE is found for compounds with a r 2 / r 1 ratio of 1.2 and an r 1 relaxivity of 20.5 m m −1 s −1 at 3 T, 18 m m −1 s −1 at 7 T and 16.5 m m −1 s −1 at 9.4 T. For compounds that do not change their r 1 relaxivity or r 2 / r 1 ratios, the necessary dose can be reduced by 10–15% owing to the improved background suppression at higher fields. Copyright © 2013 John Wiley &amp; Sons, Ltd.
Complex Roles of Inflammasomes in Carcinogenesis
2013-11-01

The central role of chronic inflammation in the promotion of tumor growth is supported by a broad range of experimental and clinical evidence. However, the molecular mechanisms converting transient inflammatory tissue reactions into a tumor-promoting microenvironment remain largely elusive. Because inflammasomes have been shown to regulate the proinflammatory cytokines interleukin 1β (IL-1β) and IL-18, they have been implicated in the relationship between tumor genesis/progression and inflammation. For instance, many cancers have been directly linked to inflammasome-mediated sterile inflammation, where a blockade of IL-1β and IL-18 has been shown to inhibit tumor growth. On the other hand, inflammasome activation also has potent antitumorigenic effects, where malignant precursor cells are eliminated through pyroptotic cell death. Indeed, inflammasome activity can even increase the efficacy of certain chemotherapies. Here, we review the current understanding on the complex and sometimes contradictory role of inflammasomes in carcinogenesis.
Efficient onbard RGBD-SLAM for autonomous MAVs
2013-11-01

We present a computationally inexpensive RGBD-SLAM solution taylored to the application on autonomous MAVs, which enables our MAV to fly in an unknown environment and create a map of its surroundings completely autonomously, with all computations running on its onboard computer. We achieve this by implementing efficient methods for both tracking its current location with respect to a heavily processed previously seen RGBD image (keyframe) and efficient relative registration of a set of keyframes using bundle adjustment with depth constraints as a front-end for pose graph optimization. We prove the accuracy and efficiency of our system based on a public benchmark dataset and demonstrate that the proposed method enables our quadrotor to fly autonomously.
Analysis of Vegetation and Soil Patterns using Hyperspectral Remote Sensing, EMI, and Gamma‐Ray Measurements
2013-11-01

The identification of spatial and temporal patterns of soil properties and moisture structures is an important challenge in environmental and soil monitoring as well as for soil landscape model approaches. This work examines the use of hyperspectral remote sensing techniques for quantifying geophysical parameters from the hyperspectral reflectance of the vegetation canopy. These can be used as proxies of the underlying soil and soil water conditions. Different spectral index derivatives, single band reflectance, and spectral indices from the airborne hyperspectral sensor AISA were quantified and tested in univariate and multivariate regression models for their correlation with geophysical measurements with electromagnetic induction (EMI) and gamma‐ray spectrometry. The best univariate models for predicting electrical conductivity based on spectral information were based on the vertical dipole of an EM38DD with an R 2 = 0.54 with the spectral index Normalized Pigments Reflectance Index (NPCI) as well as for the horizontal dipole of an EM38DD with an R 2 = 0.65 with the spectral index NPCI. For predicting soil characteristics measured with gamma‐ray spectrometry we received the best model results for γTh with an R 2 = 0.55 with the spectral index NPCI and γK with an R 2 = 0.44 with the spectral index Triangular Vegetation Index (TVI) and NPCI. The combination of variables including the geographical elevation was tested as the input for a multivariate regression analysis. For EMI and gamma‐ray measurements, the “elevation” was found to be the most predictive variable and an integration of spectral indices into the elevation‐based model led to only a slight improvement in the predictive power for EMI. An improvement could be made to explain the variance of gamma‐ray measurement signals by combining elevation and spectral information.
Phosphate Release Kinetics in Calcareous Grassland and Forest Soils in Response to H+Addition
2013-11-01

Phosphate release kinetics in soils are of global interest because sustainable plant nutrition with phosphate will be a major concern in the future. Dissolution of phosphate-containing minerals induced by a changing rhizosphere equilibrium through proton input is one important mechanism that releases phosphate into bioavailable forms. Our objectives were (i) to determine phosphate release kinetics during H+ addition in calcareous soils of the Schwäbische Alb, Germany, and to assess the influence of (ii) land-use type (grassland vs. forest) and (iii) management intensity on reactive phosphate pools and phosphate release rate constants during H+ addition. Phosphate release kinetics were characterized by a large fast-reacting phosphatepool, which could be attributed to poorly-crystalline calcium phosphates, and a small slow-reacting phosphate pool probably originating from carbonate-bearing hydroxylapatite. Both reactive phosphate pools—as well as total phosphate concentrations (TP) in soil—were greater in grassland than in forest soils. In organically fertilized grassland soils, concentrations of released phosphate were higher than in unfertilized soils, likely because organic fertilizers contain poorly-crystalline phosphate compounds which are further converted into sparingly soluble phosphate forms. Because of an enriched slow-reacting phosphate pool, mown pastures were characterized by a more continuous slow phosphate release reaction in contrast to clear biphasic phosphate release patterns in meadows. Consequently, managing phosphate release kinetics via management measures is a valuable tool to evaluate longer-term P availability in soil in the context of finite rock phosphate reserves on earth.
Analysis of Cooperative Awareness Message rates in VANETs
2013-11-01

To support applications for environment perception in Vehicular Ad-Hoc Networks (VANETs), vehicles send Cooperative Awareness Messages (CAMs) via wireless broadcast to inform other vehicles about their status. Each message received by a vehicle is processed by several application modules that run on hardware with limited resources whose capacity is not yet defined. Therefore, the received rate of CAMs is a crucial input for the development of series VANET products. In this paper, we quantify the received rate of CAMs and show that it can be high even for a low fraction of vehicles generating CAMs. We simulate road traffic in typical highway scenarios and estimate sent CAM rates. We introduce the notion of relative channel load and present a new approximative channel model to determine a vehicle's message reception probability. We use that model to simulate a vehicle's received CAM rates and propose a simple approximation formula.
Effect of metallo-β-lactamase production and multidrug resistance on clinical outcomes in patients with Pseudomonas aeruginosabloodstream infection: a retrospective cohort study
2013-11-01

Medication with appropriate antimicrobial agents at any time during the course of infection remains the key for improving clinical outcomes in patients with P. aeruginosa BSI and should be combined with a strict implementation of routine infection control measures.
SPH‐based simulation of multi‐material asteroid collisions
2013-11-01

Abstract We give a brief introduction to smoothed particle hydrodynamics methods for continuum mechanics. Specifically, we present our 3D SPH code to simulate and analyze collisions of asteroids consisting of two types of material: basaltic rock and ice. We consider effects like brittle failure, fragmentation, and merging in different impact scenarios. After validating our code against previously published results we present first collision results based on measured values for the Weibull flaw distribution parameters of basalt. (© 2013 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)
Decentralized Task Assignment and Centralized Contracting: On the Optimal Allocation of Authority
2013-11-01

ABSTRACT To provide efficient incentives, the three components of an incentive system (i.e., performance measurement, rewards, and the allocation of decision rights) need to be balanced against each other. In practice, the authority to decide on these components is frequently distributed across hierarchical levels, thus requiring adjusting centralized decisions with regard to decentralized authority. This paper investigates the centralized design of incentive contracts when decision authority, with respect to the allocation of tasks, is delegated to lower hierarchical levels. It provides an analysis of the optimal allocation of authority (i.e., “who should be the boss”) and considers the interdependencies between organizational design choices and the design of optimal incentives.
Failed sperm development as a reproductive isolating barrier between species
2013-11-01

SUMMARY Hybrid male sterility is a common reproductive isolating barrier between species. Yet, little is known about the actual developmental causes of this phenomenon, especially in naturally hybridizing species. We sought to evaluate the developmental causes of hybrid male sterility, using spadefoot toads as our study system. Plains spadefoot toads ( Spea bombifrons ) and Mexican spadefoot toads ( S. multiplicata ) hybridize where they co‐occur in the southwestern USA. Hybrids are viable, but hybrid males suffer reduced fertility. We compared testes size and developmental stages of sperm cell maturation between hybrid males and males of each species. We found that testes of hybrid males did not differ in mean size from pure‐species males. However, hybrids showed a greater range of within‐individual variation in testes size than pure‐species males. Moreover, although hybrids produced similar numbers of early stage sperm cells, hybrids produced significantly fewer mature spermatozoids than pure‐species males. Interestingly, an introgressed individual produced numbers of live sperm comparable to pure‐species males, but the majority of these sperm cells were abnormally shaped and non‐motile. These results indicate that hybrid incompatibilities in late sperm development serve as a reproductive isolating barrier between species. The nature of this breakdown highlights the possibilities that hybrid males may vary in fertility and that fertility could possibly be recovered in introgressed males.
In vivo visualization of single native pancreatic islets in the mouse
2013-11-01

The purpose of this study was to investigate the potential of a novel targeted contrast agent (CA) for the in vivo visualization of single native pancreatic islets, the sites of insulin production, in the pancreas of mice using magnetic resonance imaging (MRI). The CA for intravenous administration was composed of the β ‐cell‐specific single‐chain antibody fragment, SCA B1, and ferromagnetic carbon‐coated cobalt nanoparticles. MRI experiments were performed at 7, 9.4 and 16.4 T in excised organs (pancreas, liver, kidney, spleen), at 7 T in mice fixed in formalin and at 9.4 and 16.4 T in living mice. Image contrast in untreated control animals was compared with images from mice treated with unspecific and specific CA. For the validation of MRI results, selected pancreases were subjected to immunohistochemical staining and numerical contrast simulations were performed. Ex vivo results and the outcome of immunohistochemistry suggest that islets are marked only by the CA containing SCA B1. Strong accumulation of particles was found also in other investigated organs owing to the uptake by the reticuloendothelial system, but the contrast in the MR images is clearly distinguishable from the islet specific contrast in pancreases and numerical predictions. In vivo experiments based on averaged dynamic sampling with 66 × 66 × 100 μm 3 and triggered acquisition with 90 × 90 × 200 μm 3 nominal resolution resulted in similar particle contrast to in in vitro measurements. The newly developed CA and MRI strategies have the potential to be used for studying mouse diabetes models by visualizing single native pancreatic islets. Copyright © 2013 John Wiley &amp; Sons, Ltd.
Volitional regulation of the supplementary motor area with fMRI-BCI neurofeedback in Parkinson's disease: A pilot study
2013-11-01

It is hypothesized that a dysfunction of the supplementary motor area (SMA), secondary to a deficit of the nigrostriatal dopamine system, partially contributes to the symptomatology of Parkinson's disease (PD), i.e., akinesia. In this pilot study we investigated the effect of real-time fMRI neurofeedback based volitional up-regulation of the SMA on hand motor performance of one PD patient and 3 healthy volunteers. The effect of learned self-regulation was evaluated with speeded, bimanual, sequenced button-pressing trials, assessed immediately after each baseline and up-regulation block. Our pilot results indicate that volitional up-regulation of SMA is accompanied by slowing of sequenced button presses.
Simultaneous vs. sequential and unipolar vs. multipolar stimulation in retinal prostheses
2013-11-01

A computational model for research on retinal implants is presented. In this model, the electric field produced by a multi-electrode array in a uniform retina is calculated. It is shown how this model can be used to answer questions as to cross talk of activated electrodes, bunching of field lines in monopole and dipole activation, sequential stimulation, multipolar stimulation, etc. The model is equally applicable to epiretinal, subretinal, and suprachoroidal vision implants.
Mapping UHF RFID tags with a mobile robot using a 3D sensor model
2013-11-01

Recently, researchers showed growing interest in utilizing UHF Radio-Frequency Identification (RFID) technology for localizing tagged items with mobile robots in industrial scenarios. In this paper we present a novel three-dimensional (3D) probability sensor model of RFID antennas in the context of mapping passive RFID tags with mobile robots. The proposed 3D sensor model characterizes both detection rates and received signal strength (RSS). Compared to 2D-sensor model based approaches, the 3D model gains a higher mapping accuracy for 2D position estimation. Specially, with this sensor model, we are able to localize the tags in 3D by integrating the measurements from a pair of RFID antennas mounted at different heights of the robot. Furthermore, by integrating negative information (i.e., non-detections), the 3D mapping accuracy can be improved. Additionally, we utilize KLD-sampling to reduce the number of particles for our specific application, so that our algorithm can be performed online. Indoor experiments with a Scitos G5 robot demonstrate the effectiveness of our approach. We also provide the datasets of this work for download.
Freezing in it-clefts
2013-11-01

Freezing is the cover term for the restriction on extraction from constituents in a derived position. The traditional Freezing cases are illustrated here with topicalization in (1a), heavy-NP shift in (1b), and extraposition in (1c).
Movement related cortical potentials change after EEG-BMI rehabilitation in chronic stroke
2013-11-01

Movement related cortical potentials (MRCPs) have been studied for many years and proposed as reliable and immediate indicators of cortical reorganizations in motor learning and after stroke. It has been reported that decrease in amplitude and later onset of MRCPs reflect less mental effort and shorter planning time during a motor task. In this study MRCPs preceding hand movements in severe chronic stroke were investigated in an EEG screening paradigm (patients performed hand open and close for paretic and healthy hand) before and after a one-month online-EEG-Brain-Machine-Interface neurorehabilitation intervention coupled with physiotherapy. Five severely impaired (no residual finger extension) chronic stoke patients were enrolled in the study. We observed that MRCPs peak amplitude over Cz during paretic hand movement attempts decreased significantly after compared to before intervention. Furthermore, MRCP onset was significantly later over central regions during paretic hand movements after compared to before intervention. There were no significant pre-post differences during healthy hand movements. Our results suggest that our patients needed less mental effort and shorter planning time after intervention. We demonstrated for the first time significant MRCP changes after a neurorehabilitation intervention (BMI + physiotherapy) in severe chronic stroke patients.
Similar, but still different: how US multinational companies in Germany and Switzerland use host‐country training and skill practices
2013-11-01

Abstract We examine in how far US subsidiaries in G ermany and S witzerland display characteristics of a strategic fit with their host country and mostly find support for our predictions. Subsequently we determine each subsidiary's host‐country fit and test for within country differences in using local training and skill practices. We find the extent of continuing vocational education and training and the extent to which training on the job is important to vary with host‐country fit in G ermany, while in S witzerland, as predicted, we find no such relations.
Perception of spectrally degraded reflexives and pronouns by children
2013-11-01

Speech perception skills in cochlear-implant users are often measured with simple speech materials. In children, it is crucial to fully characterize linguistic development, and this requires linguistically more meaningful materials. The authors propose using the comprehension of reflexives and pronouns, as these specific skills are acquired at different ages. According to the literature, normal-hearing children show adult-like comprehension of reflexives at age 5, while their comprehension of pronouns only reaches adult-like levels around age 10. To provide normative data, a group of younger children (5 to 8 yrs old), older children (10 and 11 yrs old), and adults were tested under conditions without or with spectral degradation, which simulated cochlear-implant speech transmission with four and eight channels. The results without degradation confirmed the different ages of acquisition of reflexives and pronouns. Adding spectral degradation reduced overall performance; however, it did not change the general pattern observed with non-degraded speech. This finding confirms that these linguistic milestones can also be measured with cochlear-implanted children, despite the reduced quality of sound transmission. Thus, the results of the study have implications for clinical practice, as they could contribute to setting realistic expectations and therapeutic goals for children who receive a cochlear implant.