bluuebunny/crossref_metadata_2025_split huggingface dataset:
New bounds for the minimum eigenvalue of 𝓜-tensors
Authors: Zhao Jianxing , Sang Caili 
Published: March 2017

Abstract
A new lower bound and a new upper bound for the minimum eigenvalue of an 𝓜-tensor are obtained. It is proved that the new lower and upper bounds improve the corresponding bounds provided by He and Huang (J. Inequal. Appl., 2014, 2014, 114) and Zhao and Sang (J. Inequal. Appl., 2016, 2016, 268). Finally, two numerical examples are given to verify the theoretical results.
Learnheuristics: hybridizing metaheuristics with machine learning for optimization with dynamic inputs
Authors: Calvet Laura , Armas Jésica de , Masip David , Juan Angel A. 
Published: March 2017

AbstractThis paper reviews the existing literature on the combination of metaheuristics with machine learning methods and then introduces the concept of learnheuristics, a novel type of hybrid algorithms. Learnheuristics can be used to solve combinatorial optimization problems with dynamic inputs (COPDIs). In these COPDIs, the problem inputs (elements either located in the objective function or in the constraints set) are not fixed in advance as usual. On the contrary, they might vary in a predictable (non-random) way as the solution is partially built according to some heuristic-based iterative process. For instance, a consumer’s willingness to spend on a specific product might change as the availability of this product decreases and its price rises. Thus, these inputs might take different values depending on the current solution configuration. These variations in the inputs might require from a coordination between the learning mechanism and the metaheuristic algorithm: at each iteration, the learning method updates the inputs model used by the metaheuristic.
Design and Analysis of an Interconnected Suspension for a Small Off-Road Vehicle
Authors: Minaker Bruce P. , Yao Zheng 
Published: March 2017

Abstract
The paper describes the design and multibody dynamic analysis of a mechanically interconnected suspension, as applied to a small off-road vehicle. Interconnected suspensions use some sort of connection between the axles of a vehicle in order improve ride quality or vehicle handling. In principle, the connection may be hydraulic, pneumatic, or mechanical, but for installation in a typical passenger car, a mechanical connection would likely be impractical due to weight and complexity. In this paper, the vehicle in question is the University of Windsor SAE Baja off-road competition vehicle, and novel mechanical design is proposed. A multibody dynamic analysis is performed on the proposed design using the EoM open source multibody software developed by the University of Windsor Vehicle Dynamics and Control research group in order to assess any potential performance improvements.
Semi-Automatic Apparatus for Measuring Wetting Properties at High Temperatures
Authors: Bąkała Marcin , Wojciechowski Rafał , Sankowski Dominik , Rylski Adam 
Published: March 2017

Abstract
Determination of the physico-chemical interactions between liquid and solid substances is a key technological factor in many industrial processes in metallurgy, electronics or the aviation industry, where technological processes are based on soldering/brazing technologies. Understanding of the bonding process, reactions between materials and their dynamics enables to make research on new materials and joining technologies, as well as to optimise and compare the existing ones. The paper focuses on a wetting force measurement method and its practical implementation in a laboratory stand – an integrated platform for automatic wetting force measurement at high temperatures. As an example of using the laboratory stand, an analysis of Ag addition to Cu-based brazes, including measurement of the wetting force and the wetting angle, is presented.
Comparison of Time Warping Algorithms for Rail Vehicle Velocity Estimation in Low Speed Scenarios
Authors: Hensel Stefan , Marinov Marin B. 
Published: March 2017

Abstract
Precise measurement of rail vehicle velocities is an essential prerequisite for the implementation of modern train control systems and the improvement of transportation capacity and logistics. Novel eddy current sensor systems make it possible to estimate velocity by using cross-correlation techniques, which show a decline in precision in areas of high accelerations. This is due to signal distortions within the correlation interval. We propose to overcome these problems by employing algorithms from the field of dynamic programming. In this paper we evaluate the application of correlation optimized warping, an enhanced version of dynamic time warping algorithms, and compare it with the classical algorithm for estimating rail vehicle velocities in areas of high accelerations and decelerations.
MRI reduces variation of contouring for boost clinical target volume in breast cancer patients without surgical clips in the tumour bed
Authors: Al-Hammadi Noora , Caparrotti Palmira , Divakar Saju , Riyas Mohamed , Chandramouli Suparna Halsnad , Hammoud Rabih , Hayes Jillian , Mc Garry Maeve , Paloor Satheesh Prasad , Petric Primoz 
Published: March 2017

AbstractBackgroundOmitting the placement of clips inside tumour bed during breast cancer surgery poses a challenge for delineation of lumpectomy cavity clinical target volume (CTVLC). We aimed to quantify inter-observer variation and accuracy for CT- and MRI-based segmentation of CTVLCin patients without clips.Patients and methodsCT- and MRI-simulator images of 12 breast cancer patients, treated by breast conserving surgery and radiotherapy, were included in this study. Five radiation oncologists recorded the cavity visualization score (CVS) and delineated CTVLCon both modalities. Expert-consensus (EC) contours were delineated by a senior radiation oncologist, respecting opinions of all observers. Inter-observer volumetric variation and generalized conformity index (CIgen) were calculated. Deviations from EC contour were quantified by the accuracy index (AI) and inter-delineation distances (IDD).ResultsMean CVS was 3.88 +/− 0.99 and 3.05 +/− 1.07 for MRI and CT, respectively (p = 0.001). Mean volumes of CTVLCwere similar: 154 +/− 26 cm3on CT and 152 +/− 19 cm3on MRI. Mean CIgenand AI were superior for MRI when compared with CT (CIgen: 0.74 +/− 0.07 vs. 0.67 +/− 0.12, p = 0.007; AI: 0.81 +/− 0.04 vs. 0.76 +/− 0.07; p = 0.004). CIgenand AI increased with increasing CVS. Mean IDD was 3 mm +/− 1.5 mm and 3.6 mm +/− 2.3 mm for MRI and CT, respectively (p = 0.017).ConclusionsWhen compared with CT, MRI improved visualization of post-lumpectomy changes, reduced interobserver variation and improved the accuracy of CTVLCcontouring in patients without clips in the tumour bed. Further studies with bigger sample sizes are needed to confirm our findings.
Effects of Environmental Pollution on Fish: A Short Review
Authors: Khoshnood Zahra 
Published: March 2017

Abstract
Environmental contaminants, such as heavy metals and pesticides, are the most important toxic compounds of aquatic habitats. Heavy metals enter the aquatic environments via natural and anthropogenic pathways while the only source of pesticides is the anthropogenic usage of different types of pesticides including fungicide, insecticide and herbicide. Fish larvae and fingerlings are the most vulnerable life stages of fish which could be severely affected by pesticides as non-target organisms as well as by heavy metal pollution. The most important tissues affected by these pollutants are the gill, kidney and liver. Histopathological alterations of these vital organs could affect the survival rate, biological activities, osmoregulation, reproduction, buoyancy, etc., which finally could lead to failures in stock recruitment and population changes.
Disambiguating Praxis from Practice in Natural Resource Management: A Practical Space for Enhancing Experiential Learning in the Eastern Coast of Tanzania
Authors: Sabai Daniel 
Published: March 2017

Abstract
It is evident that practice and praxis have significantly contributed to knowledge generation in the Tanzanian coastal belt, especially where Integrated Coastal Management (ICM) programmes have been adopted and practiced such as Tanga, Dar es Salaam, Mtwara, Lindi, and the Coastal region (KICAMP, 2001; NICEMS, 2003). In spite of such learning evidences, users of generated natural resource data in the coastal area tend to employ practice and praxis interchangeably, conflating the two concepts together; leading to a situation where one may hardly ascribe generated knowledge appropriately to contexts that favour occurrence of each of the two constructs. The paper adopts ethnographic approach in a defined coastal case study to examine contexts and situations that signals “conflationˮ and it employs examples that may help readers of the article to disambiguate praxis from practice.
Working Memory Load Strengthens Reward Prediction Errors
Authors: Collins Anne G.E. , Ciullo Brittany , Frank Michael J. , Badre David 
Published: March 2017

Reinforcement learning (RL) in simple instrumental tasks is usually modeled as a monolithic process in which reward prediction errors (RPEs) are used to update expected values of choice options. This modeling ignores the different contributions of different memory and decision-making systems thought to contribute even to simple learning. In an fMRI experiment, we investigated how working memory (WM) and incremental RL processes interact to guide human learning. WM load was manipulated by varying the number of stimuli to be learned across blocks. Behavioral results and computational modeling confirmed that learning was best explained as a mixture of two mechanisms: a fast, capacity-limited, and delay-sensitive WM process together with slower RL. Model-based analysis of fMRI data showed that striatum and lateral prefrontal cortex were sensitive to RPE, as shown previously, but, critically, these signals were reduced when the learning problem was within capacity of WM. The degree of this neural interaction related to individual differences in the use of WM to guide behavioral learning. These results indicate that the two systems do not process information independently, but rather interact during learning.SIGNIFICANCE STATEMENTReinforcement learning (RL) theory has been remarkably productive at improving our understanding of instrumental learning as well as dopaminergic and striatal network function across many mammalian species. However, this neural network is only one contributor to human learning and other mechanisms such as prefrontal cortex working memory also play a key role. Our results also show that these other players interact with the dopaminergic RL system, interfering with its key computation of reward prediction errors.
Multivoxel Pattern Analysis Reveals 3D Place Information in the Human Hippocampus
Authors: Kim Misun , Jeffery Kate J. , Maguire Eleanor A. 
Published: March 2017

The spatial world is three dimensional (3D) and humans and other animals move both horizontally and vertically within it. Extant neuroscientific studies have typically investigated spatial navigation on a horizontal 2D plane, leaving much unknown about how 3D spatial information is represented in the brain. Specifically, horizontal and vertical information may be encoded in the same or different neural structures with equal or unequal sensitivity. Here, we investigated these possibilities using fMRI while participants were passively moved within a 3D lattice structure as if riding a rollercoaster. Multivoxel pattern analysis was used to test for the existence of information relating to where and in which direction participants were heading in this virtual environment. Behaviorally, participants had similarly accurate memory for vertical and horizontal locations and the right anterior hippocampus (HC) expressed place information that was sensitive to changes along both horizontal and vertical axes. This is suggestive of isotropic 3D place encoding. In contrast, participants indicated their heading direction faster and more accurately when they were heading in a tilted-up or tilted-down direction. This direction information was expressed in the right retrosplenial cortex and posterior HC and was only sensitive to vertical pitch, which could reflect the importance of the vertical (gravity) axis as a reference frame. Overall, our findings extend previous knowledge of how we represent the spatial world and navigate within it by taking into account the important third dimension.SIGNIFICANCE STATEMENTThe spatial world is 3D. We can move horizontally across surfaces, but also vertically, going up slopes or stairs. Little is known about how the brain supports representations of 3D space. A key question is whether horizontal and vertical information is equally well represented. Here, we measured fMRI response patterns while participants moved within a virtual 3D environment and found that the anterior hippocampus (HC) expressed location information that was sensitive to the vertical and horizontal axes. In contrast, information about heading direction, found in retrosplenial cortex and posterior HC, favored the vertical axis, perhaps due to gravity effects. These findings provide new insights into how we represent our spatial 3D world and navigate within it.
Prefrontal Cortex KCa2 Channels Regulate mGlu5-Dependent Plasticity and Extinction of Alcohol-Seeking Behavior
Authors: Cannady Reginald , McGonigal Justin T. , Newsom Ryan J. , Woodward John J. , Mulholland Patrick J. , Gass Justin T. 
Published: March 2017

Identifying novel treatments that facilitate extinction learning could enhance cue-exposure therapy and reduce high relapse rates in alcoholics. Activation of mGlu5receptors in the infralimbic prefrontal cortex (IL-PFC) facilitates learning during extinction of cue-conditioned alcohol-seeking behavior. Small-conductance calcium-activated potassium (KCa2) channels have also been implicated in extinction learning of fear memories, and mGlu5receptor activation can reduce KCa2 channel function. Using a combination of electrophysiological, pharmacological, and behavioral approaches, this study examined KCa2 channels as a novel target to facilitate extinction of alcohol-seeking behavior in rats. This study also explored related neuronal and synaptic mechanisms within the IL-PFC that underlie mGlu5-dependent enhancement of extinction learning. Using whole-cell patch-clamp electrophysiology, activation of mGlu5inex vivoslices significantly reduced KCa2 channel currents in layer V IL-PFC pyramidal neurons, confirming functional downregulation of KCa2 channel activity by mGlu5receptors. Additionally, positive modulation of KCa2 channels prevented mGlu5receptor-dependent facilitation of long-term potentiation in the IL-PFC. Systemic and intra-IL-PFC treatment with apamin (KCa2 channel allosteric inhibitor) significantly enhanced extinction of alcohol-seeking behavior across multiple extinction sessions, an effect that persisted for 3 weeks, but was not observed after apamin microinfusions into the prelimbic PFC. Positive modulation of IL-PFC KCa2 channels significantly attenuated mGlu5-dependent facilitation of alcohol cue-conditioned extinction learning. These data suggest that mGlu5-dependent facilitation of extinction learning and synaptic plasticity in the IL-PFC involves functional inhibition of KCa2 channels. Moreover, these findings demonstrate that KCa2 channels are a novel target to facilitate long-lasting extinction of alcohol-seeking behavior.SIGNIFICANCE STATEMENTAlcohol use disorder is a chronic relapsing disorder that is associated with compulsive alcohol-seeking behavior. One of the main causes of alcohol relapse is the craving caused by environmental cues that are associated with alcohol. These cues are formed by normal learning and memory principles, and the understanding of the brain mechanisms that help form these associations can lead to the development of drugs and/or behavior therapies that reduce the impact that these cues have on relapse in alcoholics.
STAT3 Controls the Long-Term Survival and Phenotype of Repair Schwann Cells during Nerve Regeneration
Authors: Benito Cristina , Davis Catherine M. , Gomez-Sanchez Jose A. , Turmaine Mark , Meijer Dies , Poli Valeria , Mirsky Rhona , Jessen Kristjan R. 
Published: March 2017

After nerve injury, Schwann cells convert to a phenotype specialized to promote repair. But during the slow process of axonal regrowth, these repair Schwann cells gradually lose their regeneration-supportive features and eventually die. Although this is a key reason for the frequent regeneration failures in humans, the transcriptional mechanisms that control long-term survival and phenotype of repair cells have not been studied, and the molecular signaling underlying their decline is obscure. We show, in mice, that Schwann cell STAT3 has a dual role. It supports the long-term survival of repair Schwann cells and is required for the maintenance of repair Schwann cell properties. In contrast, STAT3 is less important for the initial generation of repair Schwann cells after injury. In repair Schwann cells, we find that Schwann cell STAT3 activation by Tyr705 phosphorylation is sustained during long-term denervation. STAT3 is required for maintaining autocrine Schwann cell survival signaling, and inactivation of Schwann cell STAT3 results in a striking loss of repair cells from chronically denervated distal stumps. STAT3 inactivation also results in abnormal morphology of repair cells and regeneration tracks, and failure to sustain expression of repair cell markers, including Shh, GDNF, and BDNF. Because Schwann cell development proceeds normally without STAT3, the function of this factor appears restricted to Schwann cells after injury. This identification of transcriptional mechanisms that support long-term survival and differentiation of repair cells will help identify, and eventually correct, the failures that lead to the deterioration of this important cell population.SIGNIFICANCE STATEMENTAlthough injured peripheral nerves contain repair Schwann cells that provide signals and spatial clues for promoting regeneration, the clinical outcome after nerve damage is frequently poor. A key reason for this is that, during the slow growth of axons through the proximal parts of injured nerves repair, Schwann cells gradually lose regeneration-supporting features and eventually die. Identification of signals that sustain repair cells is therefore an important goal. We have found that in mice the transcription factor STAT3 protects these cells from death and contributes to maintaining the molecular and morphological repair phenotype that promotes axonal regeneration. Defining the molecular mechanisms that maintain repair Schwann cells is an essential step toward developing therapeutic strategies that improve nerve regeneration and functional recovery.
Distinct Actions of Voltage-Activated Ca2+Channel Block on Spontaneous Release at Excitatory and Inhibitory Central Synapses
Authors: Tsintsadze Timur , Williams Courtney L. , Weingarten Dennis J. , von Gersdorff Henrique , Smith Stephen M. 
Published: March 2017

At chemical synapses, voltage-activated calcium channels (VACCs) mediate Ca2+influx to trigger action potential-evoked neurotransmitter release. However, the mechanisms by which Ca2+regulates spontaneous transmission have not been fully determined. We have shown that VACCs are a major trigger of spontaneous release at neocortical inhibitory synapses but not at excitatory synapses, suggesting fundamental differences in spontaneous neurotransmission at GABAergic and glutamatergic synapses. Recently, VACC blockers were reported to reduce spontaneous release of glutamate and it was proposed that there was conservation of underlying mechanisms of neurotransmission at excitatory and inhibitory synapses. Furthermore, it was hypothesized that the different effects on excitatory and inhibitory synapses may have resulted from off-target actions of Cd2+, a nonselective VACC blocker, or other variations in experimental conditions. Here we report that in mouse neocortical neurons, selective and nonselective VACC blockers inhibit spontaneous release at inhibitory but not at excitatory terminals, and that this pattern is observed in culture and slice preparations as well as in synapses from acute slices of the auditory brainstem. The voltage dependence of Cd2+block of VACCs accounts for the apparent lower potency of Cd2+on spontaneous release of GABA than on VACC current amplitudes. Our findings indicate fundamental differences in the regulation of spontaneous release at inhibitory and excitatory synapses by stochastic VACC activity that extend beyond the cortex to the brainstem.SIGNIFICANCE STATEMENTPresynaptic Ca2+entry via voltage-activated calcium channels (VACCs) is the major trigger of action potential-evoked synaptic release. However, the role of VACCs in the regulation of spontaneous neurotransmitter release (in the absence of a synchronizing action potential) remains controversial. We show that spontaneous release is affected differently by VACCs at excitatory and inhibitory synapses. At inhibitory synapses, stochastic openings of VACCs trigger the majority of spontaneous release, whereas they do not affect spontaneous release at excitatory synapses. We find this pattern to be wide ranging, holding for large and small synapses in the neocortex and brainstem. These findings indicate fundamental differences of the Ca2+dependence of spontaneous release at excitatory and inhibitory synapses and heterogeneity of the mechanisms of release across the CNS.
The Effects of Obstructive Sleep Apnea Syndrome on the Dentate Gyrus and Learning and Memory in Children
Authors: Cha Jiook , Zea-Hernandez Johanna A. , Sin Sanghun , Graw-Panzer Katharina , Shifteh Keivan , Isasi Carmen R. , Wagshul Mark E. , Moran Eileen E. , Posner Jonathan , Zimmerman Molly E. , Arens Raanan 
Published: March 2017

Obstructive sleep apnea syndrome (OSAS) is associated with intermittent hypoxia and sleep loss. In children, impairments of cognitive function are important manifestations, but the underlying pathology is unknown. We hypothesized that OSAS would affect the dentate gyrus, a hippocampal subdivision essential to neurogenesis and cognition, and that this impact would further affect cognitive function in children. In children with OSAS (n= 11) and control subjects (n= 12; age and sex matched), we performed diffusion tensor imaging and structural MRI, polysomnography, and neuropsychological assessments. We found that OSAS was associated with decreased mean diffusivity of the left dentate gyrus (p= 0.002; false discovery rate corrected; adjusting for sex, age, and body mass index), showing a large effect size (partial η2= 0.491), but not with any other structural measures across the brain. Decreased dentate gyrus mean diffusivity correlated with a higher apnea hypopnea index (Spearman'sr= −0.50,p= 0.008) and a greater arousal index (r= −0.44,p= 0.017). OSAS did not significantly affect neuropsychological measures (pvalues >0.5); however, a lower verbal learning score correlated with lower dentate gyrus mean diffusivity (r= 0.54,p= 0.004). Path analysis demonstrated that dentate gyrus mean diffusivity mediates the impact of OSAS on verbal learning capacity. Finally, the diagnostic accuracy of a regression model based on dentate gyrus mean diffusivity reached 85.8% (cross validated). This study demonstrates a likely pathway of effects of OSAS on neurocognitive function in children, as well as potential utility of the dentate gyrus mean diffusivity as an early marker of brain pathology in children with OSAS.SIGNIFICANCE STATEMENTIn this study we investigate the relationships between dentate gyrus structure, hippocampus-dependent cognition, and obstructive sleep apnea syndrome (OSAS). We demonstrate lower mean diffusivity of the dentate gyrus in children with OSAS, which correlates with a lower verbal learning and memory score. This study provides new evidence of disrupted microstructure of the dentate gyrus in children with OSAS that may help explain some of the neurocognitive deficits described in these children.