bluuebunny/crossref_metadata_2025_split huggingface dataset:
Smooth Estimation of a Lifetime Distribution with Competing Risks by Using Regular Interval Observations: Application to Cocoa Fruits Growth
Authors: Soh Patrice Takam , Nguéma Eugène-Patrice Ndong , Gwet Henri , Ndoumbè-Nkeng Michel 
Published: September 2013

SummaryIn the estimation of a lifetime distribution from regular interval-censored data with an additional censoring variable, we focus on the case where (contrary to the actuarial method) both events (interest and censorship) can occur on a given individual in the same interval and, thus, are observed simultaneously. Specifically, we consider a population where individuals pass through a finite number of successive stages during their growth and are threatened by a disease. First, we estimate the lifetime and time-to-disease distributions in each developmental stage from such censored data. Using data that were recorded on a cohort of individuals followed over a long period of time, we propose a non-parametric, yet continuously differentiable and piecewise quadratic polynomial, estimator for the survival function of each of these distributions. We applied it to estimate, from weekly field observations in Mbankomo (Cameroon), the lifetime and time-to-disease distributions of cocoa fruits in each of their three developmental stages before maturity. It is found that on average a healthy cocoa fruit spends only 212 weeks in its first stage (cherelle), compared with nearly 9 weeks as a young pod and 712 weeks as an adult pod. In a second phase, however, adapting our methodology to competing risks estimation, we observed that, owing to the severe rate of attacks, the fruits' effective lifetime expectancy in farmland is much shorter. Indeed, in that part of Cameroon, the cumulative risk of an attack on cocoa fruits in farmland, especially by pod rot disease, far outweighs their chances of reaching maturity.
Initiation of Dialysis Should be Timely: Neither Early Nor Late
Authors: Mehrotra Rajnish , Rivara Matthew , Himmelfarb Jonathan 
Published: September 2013

AbstractOver the last decade, individuals with end‐stage renal disease (ESRD) in the United States are starting maintenance dialysis therapy at progressively higher estimated glomerular filtration rate (eGFR). Moreover, several observational studies have demonstrated an association of a higher risk of death with higher serum creatinine‐based estimates of GFR at the time of initiation of dialysis. In contrast, studies in which renal function has been measured by timed urinary collection show either a lower risk of death or no significant association with higher GFR at the time of initiation of dialysis. There are numerous potential sources of bias in such observational studies, particularly in those that use serum creatinine‐based eGFR. The only randomized controlled clinical trial to have examined this question did not demonstrate either benefit or harm with initiation of dialysis at higher level of renal function. Thus, the data to date suggest that eGFR should not be the sole consideration when assessing the need for initiating maintenance dialysis in patients with advanced chronic kidney disease. Given the high societal costs of starting renal replacement therapy earlier in the course of the disease, these considerations also suggest that dialysis can be safely be postponed in otherwise asymptomatic individuals with advanced chronic kidney disease. By the same token, dialysis should not be denied to individuals who could clearly benefit from renal replacement therapy simply because the GFR is too high (viz., volume overload, refractory hyperkalemia). Finally, there is a compelling need to reexamine the symptoms that could be attributed to uremia and clearly improve upon initiation of dialysis to better guide clinical decision‐making.
Fast Censored Linear Regression
Authors: Huang Yijian 
Published: September 2013

ABSTRACTWeighted log‐rank estimating function has become a standard estimation method for the censored linear regression model, or the accelerated failure time model. Well established statistically, the estimator defined as a consistent root has, however, rather poor computational properties because the estimating function is neither continuous nor, in general, monotone. We propose a computationally efficient estimator through an asymptotics‐guided Newton algorithm, in which censored quantile regression methods are tailored to yield an initial consistent estimate and a consistent derivative estimate of the limiting estimating function. We also develop fast interval estimation with a new proposal for sandwich variance estimation. The proposed estimator is asymptotically equivalent to the consistent root estimator and barely distinguishable in samples of practical size. However, computation time is typically reduced by two to three orders of magnitude for point estimation alone. Illustrations with clinical applications are provided.
Texture‐dependent motion signals in primate middle temporal area
Authors: Gharaei Saba , Tailby Chris , Solomon Selina S. , Solomon Samuel G. 
Published: September 2013

Key points
The receptive fields of neurons in the middle temporal (MT) area of primate visual cortex are an important stage in motion analysis. Some neurons in MT (pattern cells) can signal motion independent of contour orientation, but others (component cells) cannot; there is no systematic account of how responses in area MT depend on the spatial structure of images.
We measured the extracellular response of neurons in area MT of anaesthetised marmoset monkeys to synthetic textures and natural images.
Direction tuning of pattern cells was broad and largely stable against variation in spatial texture. Direction tuning of component cells was narrower than that of pattern cells when spatial textures contained few orientations, but tuning was not stable against variation in spatial texture.
Response variability in all neurons was lower for rich spatial texture.
Pattern and component cells may provide parallel analyses for motion vision.
Abstract  Neurons in the middle temporal (MT) area of primate cortex provide an important stage in the analysis of visual motion. For simple stimuli such as bars and plaids some neurons in area MT – pattern cells – seem to signal motion independent of contour orientation, but many neurons – component cells – do not. Why area MT supports both types of receptive field is unclear. To address this we made extracellular recordings from single units in area MT of anaesthetised marmoset monkeys and examined responses to two‐dimensional images with a large range of orientations and spatial frequencies. Component and pattern cell response remained distinct during presentation of these complex spatial textures. Direction tuning curves were sharpest in component cells when a texture contained a narrow range of orientations, but were similar across all neurons for textures containing all orientations. Response magnitude of pattern cells, but not component cells, increased with the spatial bandwidth of the texture. In addition, response variability in all neurons was reduced when the stimulus was rich in spatial texture. Fisher information analysis showed that component cells provide more informative responses than pattern cells when a texture contains a narrow range of orientations, but pattern cells had more informative responses for broadband textures. Component cells and pattern cells may therefore coexist because they provide complementary and parallel motion signals.
Are skeletal muscle FNDC5 gene expression and irisin release regulated by exercise and related to health?
Authors: Pekkala Satu , Wiklund Petri K. , Hulmi Juha J. , Ahtiainen Juha P. , Horttanainen Mia , Pöllänen Eija , Mäkelä Kari A. , Kainulainen Heikki , Häkkinen Keijo , Nyman Kai , Alén Markku , Herzig Karl‐Heinz , Cheng Sulin 
Published: September 2013

Key points
Contradictory findings have been reported concerning the function of irisin and its precursor gene, skeletal muscle FNDC5, in energy homeostasis and metabolic health, and the associated regulatory role of exercise and PGC‐1α.
We analysed the effects of different short‐ and long‐term exercise regimens on muscle FNDC5 and PGC‐1α, and serum irisin, and studied the associations of irisin and FNDC5 with health parameters.
FNDC5 and serum irisin did not change after acute aerobic, long‐term endurance training or endurance training combined with resistance exercise (RE) training, or associate with metabolic disturbances. A single RE bout increased FNDC5 mRNA in young, but not older men (27 vs. 62 years). Changes in PGC‐1α or serum irisin were not consistently accompanied by changes in FNDC5.
Our data suggest that the effects of exercise on FNDC5 and irisin are not consistent, and that their role in health is questionable. Moreover, the regulatory mechanisms should be studied further.
Abstract  Recently, contradictory findings have been reported concerning the function of irisin and its precursor gene, skeletal muscle FNDC5, in energy homeostasis, and the associated regulatory role of exercise and PGC‐1α. We therefore evaluated whether muscle FNDC5 mRNA and serum irisin are exercise responsive and whether PGC‐1α expression is associated with FNDC5 expression. The male subjects in the study performed single exercises: (1) 1 h low‐intensity aerobic exercise (AE) (middle‐aged, n= 17), (2) a heavy‐intensity resistance exercise (RE) bout (young n= 10, older n= 11) (27 vs. 62 years), (3) long‐term 21 weeks endurance exercise (EE) training alone (twice a week, middle‐aged, n= 9), or (4) combined EE and RE training (both twice a week, middle‐aged, n= 9). Skeletal muscle mRNA expression was analysed by quantitative PCR and serum irisin by ELISA. No significant changes were observed in skeletal muscle PGC‐1α, FNDC5 and serum irisin after AE, EE training or combined EE + RE training. However, a single RE bout increased PGC‐1α by 4‐fold in young and by 2‐fold in older men, while FNDC5 mRNA only increased in young men post‐RE, by 1.4‐fold. Changes in PGC‐1α or serum irisin were not consistently accompanied by changes in FNDC5. In conclusion, for the most part, neither longer‐term nor single exercise markedly increases skeletal muscle FNDC5 expression or serum irisin. Therefore their changes in response to exercise are probably random and not consistent excluding the confirmation of any definitive link between exercise and FNDC5 expression and irisin release in humans. Moreover, irisin and FNDC5 were not associated with glucose tolerance and being overweight, or with metabolic disturbances, respectively. Finally, factor(s) other than PGC‐1α and transcription may regulate FNDC5 expression.
Culture-Negative Prosthetic Valve Endocarditis with Concomitant Septicemia Due to a Nontoxigenic Corynebacterium diphtheriae Biotype Gravis Isolate in a Patient with Multiple Risk Factors
Authors: Clinton Lani Kai , Bankowski Matthew J. , Shimasaki Teppei , Sae-Ow Wichit , Whelen A. Christian , O'Connor Norman , Kim Wesley , Young Royden 
Published: September 2013

ABSTRACTA 54-year-old female with a prosthetic mitral valve presented with a 3-day history of dizziness, subjective fever, and chills. Blood cultures were positive for a pleomorphic Gram-positive rod. Initial phenotypic testing could only support the identification of aCorynebacteriumspecies. Nucleic acid sequencing (16S rRNA) and matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) were conclusive forCorynebacterium diphtheriae. Definitive phenotypic testing classified the strain as nontoxigenicC. diphtheriaebiotype Gravis.
Atomic Structure of Cucumber Necrosis Virus and the Role of the Capsid in Vector Transmission
Authors: Li Ming , Kakani Kishore , Katpally Umesh , Johnson Sharnice , Rochon D'Ann , Smith Thomas J. 
Published: September 2013

ABSTRACT

Cucumber Necrosis Virus
(CNV) is a member of the genus
Tombusvirus
and has a monopartite positive-sense RNA genome packaged in a T=3 icosahedral particle. CNV is transmitted in nature via zoospores of the fungus
Olpidium bornovanus
. CNV undergoes a conformational change upon binding to the zoospore that is required for transmission, and specific polysaccharides on the zoospore surface have been implicated in binding. To better understand this transmission process, we have determined the atomic structure of CNV. As expected, being a member of the
Tombusvirus
genus, the core structure of CNV is highly similar to that of
Tomato bushy stunt virus
(TBSV), with major differences lying on the exposed loops. Also, as was seen with TBSV, CNV appears to have a calcium binding site between the subunits around the quasi-3-fold axes. However, unlike TBSV, there appears to be a novel zinc binding site within the β annulus formed by the N termini of the three C subunits at the icosahedral 3-fold axes. Two of the mutations causing defective transmission map immediately around this zinc binding site. The other mutations causing defective transmission and particle formation are mapped onto the CNV structure, and it is likely that a number of the mutations affect zoospore transmission by affecting conformational transitions rather than directly affecting receptor binding.
The stages of extrication: a prospective study
Authors: Nutbeam Tim , Fenwick Rob , Hobson Charles , Holland Vikki , Palmer Michael 
Published: September 2013

BackgroundMany patients will require extrication following a motor vehicle collision (MVC). Little information exists on the time taken for the various stages of extrication.ObjectiveTo report the time taken for the various stages of extrication.MethodsA prospective, observational study carried out in the West Midland Fire Service's metropolitan area. Time points related to extrication were collected ‘live’ by two-way radio broadcast. Any missing data were actively gathered by fire control within 1 h of completion of extrication. This paper reports an interim analysis conducted after 1 year of data collection following a 3-month run-in and training period: data were analysed from 1 January 2011 to 31 December 2011 inclusive.ResultsDuring the study period 228 incidents were identified. Seventy-nine were excluded as they met the predetermined exclusion criteria or had incomplete data collection. This left 158 extrications that were suitable for analysis. The median time for extrication was 30 min, IQR 24–38 min.ConclusionsIn patients requiring extrication following an MVC a median time of 8 min is typically required before initial limited patient assessment and intervention. A further 22 min is typically required before full extrication. Prehospital personnel should be aware of these times when planning their approach to a trapped patient.
SPARSE APPROXIMATION AND FIT OF INTRADAY LOAD CURVES IN A HIGH DIMENSIONAL FRAMEWORK
Authors: MOUGEOT MATHILDE , PICARD DOMINIQUE , TRIBOULEY KARINE , LEFIEUX VINCENT , MAILLARD-TEYSSIER LAURENCE 
Published: September 2013

An important perspective in electric consumption obviously is the forecasting. A crucial step in the forecasting process is the modeling. It is commonly admitted that many variables are influential for the prediction in this context. On the other hand, a prediction, to be robust and efficient, has necessarily to rely on a small number of well chosen predictors. We are typically in a situation where sparse multidimensional modeling can bring an essential input, and this paper is an attempt to prove it. In this perspective, we shall address the question of providing a sparse representation of the intraday load curves, with good approximation properties. One difficulty is that we have here a large set of potential predictors among climate variables and shape "patterns", and even if high dimensional sparse methods have clearly as objective to select among a large number of covariates, they are especially efficient when the predictors are not too correlated. So our task is twofold: first we need to operate a preselection of the predictors, and then use an appropriate sparse method. The first part and especially when shape patterns are concerned is not simple. We solve this aspect using a pre-processing in three steps process. We first provide a sparse modeling of the intraday load curves as functions of the time. Then, using the sparse representation of each load curve, we define clusters of consumption, which yield finally typical profiles, the group centroids or patterns of consumption. Then we investigate the modeling of the intraday load curves using both exogenous climate variables and endogenous consumption variables as previously designed. We exhibit, as a result, sparse models relying just on few variables and also characterized by very good approximation performances. We end by explaining how sparse approximation is a first step towards clustering. The sparse approximation is here obtained by performing a robust and simple algorithm, LOLA, presented at the end of the paper.
Repeated inversion and collapse in the Late Cretaceous–Cenozoic northern Vøring Basin, offshore Norway
Authors: Lundin Erik R. , Doré Anthony G. , Rønning Kristin , Kyrkjebø Rune 
Published: September 2013

The Norwegian Atlantic margin, although frequently described as passive, has seen several significant and highly variable deformation events prior to and after early Cenozoic break-up. This chronology is strongly exemplified in the northern Vøring Basin, where deformation resulted in significant vertical motions, including deep erosion and sediment reworking.
Post-break-up compressional deformation is well documented in the NE Atlantic margins, and is represented in the north Vøring Basin by the Vema and Naglfar domes. A prominent Maastrichtian–Paleocene pre-break-up phase of compression inverted the northern prolongation of the latest Turonian Vigrid Syncline. This syncline was the fairway for the approximately 1 km-thick Santonian–Campanian Nise Formation sandstone, shed from NE Greenland and/or the western Barents Sea margin. The inversion focused on the Vigrid Syncline axis, forming an anticline here referred to as the Vema–Nyk Anticline. The anticline may have been a major trap but was breached by erosion prior to collapse due to Late Paleocene extension. The remnant eastern half of the anticline is the Nyk High. The associated flanking syncline, the Någrind Syncline, also remains preserved. The collapsed side of the anticline is the Hel Graben, which itself was inverted in the Middle Miocene time forming the Naglfar and Vema domes.
More speculatively, the development of the Vigrid Syncline and its bounding structural highs, the Gjallar Ridge and Utgard High, may also represent folds, marking the onset of compressional buckling in the mid-Norwegian–NE Greenland rift system.
The repeated compressional deformation, as well as the extensional collapse, was focused on the area subjected to Early Cretaceous hyperextension. Compressional buckling under relatively low stress levels is proposed to have been due to significant lithosphere weakening caused by the hyperextension, whereby both high attenuation of the crystalline crust and serpentinization of the upper mantle contribute to the weakening. The Late Cenozoic compression post-dated the hyperextension by approximately 110 Ma, which suggests that the weakening is long-lived and that lithosphere has not been strengthened significantly through time.
Decomposing combinatorial auctions and set packing problems
Authors: Gottlob Georg , Greco Gianluigi 
Published: September 2013

Combinatorial auctions allow bidders to bid on bundles of items rather than just on single items. The winner determination problem in combinatorial auctions is the problem of determining the allocation of items to bidders such that the sum of the accepted bid prices is maximized. This problem is equivalent to the well-known maximum-weight set packing problem. Even though these problems are NP-hard in general, they can be solved in polynomial time on instances whose associated item graphs have bounded treewidth (called structured item graphs). However, the tractability of determining whether for a given problem instance a structured item graph of fixed treewidth exists (and if so, computing one efficiently) was an open problem.
In this article, we solve this problem by proving that deciding the existence of structured item graphs is computationally intractable, even for treewidth 3. Motivated by this unfavorable complexity result, we investigate other structural restrictions, and we show that the notion of hypertree decomposition, a well-studied measure of hypergraph cyclicity, turns out to be most useful here. Indeed, we show that the winner determination problem is solvable in polynomial time on instances whose dual auction hypergraphs have bounded hypertree width. Our solution method is based on encoding winner determination via a constraint satisfaction optimization problem and on exhibiting an algorithm to solve this latter problem efficiently for such structurally restricted instances. The class of tractable instances identified by our approach, while being efficiently recognizable, properly contains the class of instances having a structured item graph. Moreover, on the larger class, our method solves winner determination with the same asymptotic complexity as the best algorithm proposed in the literature for the subclass of structured item graphs. Hypertree decompositions can equally profitably be applied to the maximum-weight independent set problem, which is the dual problem of maximum-weight set packing.
Numerical Solution for IVP in Volterra Type Linear Integrodifferential Equations System
Authors: Ghomanjani F. , Kılıçman A. , Effati S. 
Published: September 2013

A method is proposed to determine the numerical solution of system of linear Volterra integrodifferential equations (IDEs) by using Bezier curves. The Bezier curves are chosen as piecewise polynomials of degreen, and Bezier curves are determined on[t0, tf ]by n+1control points. The efficiency and applicability of the presented method are illustrated by some numerical examples.
Cyr61 is a target for heparin in reducing MV3 melanoma cell adhesion and migration via the integrin VLA-4
Authors: Schütze Norbert , Jüngel Eva , Blaheta Roman , Naggi Annamaria , Torri Giangiacomo , Schmitz Patrick , Gerber Ursula , Bendas Gerd 
Published: September 2013

SummaryThe integrin VLA-4 is important for the metastatic dissemination of melanoma cells. We could recently show that heparin can block VLA-4 binding, which contributes, next to blocking P-and L-selectin, to the understanding of antimetastatic activities of heparin. The matricellular ligand Cyr61, secreted by numerous tumours, is responsible for increased tumourigenicity and metastasis. This has been attributed to Cyr61 binding to, and thus activating integrins. However, a VLA-4/Cyr61 axis has not yet been reported. Since Cyr61 possesses heparin binding capabilities, Cyr61 can be supposed as potential target for heparin to indirectly interfere with integrin functions. The present in vitro studies address (i) the existence of a Cyr61/VLA-4 axis and (ii) the functional relevance of heparin interference via Cyr61. The C-terminal module III of Cyr61 could be exposed as nanomolar affine binding site for VLA-4. A shRNA-based knockdown of Cyr61 in MV3 human melanoma cells reduced VLA-4-mediated cell binding to VCAM-1, migration on fibronectin, and integrin signalling functions significantly. Using a biosensor approach we provide insight into heparin interference with this process. The low-molecular-weight heparin tinzaparin, but not the pentasaccharide fondaparinux, binds module IV of Cyr61 with micromolar affinity. But tinzaparin cannot interfere with Cyr61 accumulation onto syndecan-4, indicating different Cyr61 binding sites for heparin and other GAGs. Nonetheless, tinzaparin affects the VLA-4 binding and signalling functions selectively via Cyr61 already at very low concentration most likely by blocking the cellular secreted free Cyr61. This study emphasises Cyr61 as promising, and hitherto not considered target for heparin to selectively influence integrin functions.