bluuebunny/crossref_metadata_2025_split huggingface dataset:
Robust estimation of conditional variance of time series using density power divergences
Authors: Park Jin‐Hong , Sriram T. N. 
Published: March 2017

AbstractSuppose Zt is the square of a time series Yt whose conditional mean is zero. We do not specify a model for Yt, but assume that there exists a p×1 parameter vector Φ such that the conditional distribution of Zt|Zt−1 is the same as that of
, where Zt−1=(Zt−1,…,Zt−p)T for some lag p⩾1. Consequently, the conditional variance of Yt is some function of
. To estimate Φ, we propose a robust estimation methodology based on density power divergences (DPD) indexed by a tuning parameter α∈[0,1], which yields a continuum of estimators,
, where α controls the trade‐off between robustness and efficiency of the DPD estimators. For each α,
is shown to be strongly consistent. We develop data‐dependent criteria for the selection of optimal α and lag p in practice. We illustrate the usefulness of our DPD methodology via simulation studies for ARCH‐type models, where the errors are drawn from a gross‐error contamination model and the conditional variance is a linear and/or nonlinear function of
. Furthermore, we analyze the Chicago Board Options Exchange Dow Jones volatility index data and show that our DPD approach yields viable models for the conditional variance, which are as good as, or superior to, ARCH/GARCH models and two other divergence‐based models in terms of in‐sample and out‐of‐sample forecasts.
Tuning face perception with electrical stimulation of the fusiform gyrus
Authors: Keller Corey J. , Davidesco Ido , Megevand Pierre , Lado Fred A. , Malach Rafael , Mehta Ashesh D. 
Published: March 2017

AbstractThe fusiform gyrus (FG) is an important node in the face processing network, but knowledge of its causal role in face perception is currently limited. Recent work demonstrated that high frequency stimulation applied to the FG distorts the perception of faces in human subjects (Parvizi et al. []: J Neurosci 32:14915–14920). However, the timing of this process in the FG relative to stimulus onset and the spatial extent of FG's role in face perception are unknown. Here, we investigate the causal role of the FG in face perception by applying precise, event‐related electrical stimulation (ES) to higher order visual areas including the FG in six human subjects undergoing intracranial monitoring for epilepsy. We compared the effects of single brief (100 μs) electrical pulses to the FG and non‐face‐selective visual areas on the speed and accuracy of detecting distorted faces. Brief ES applied to face‐selective sites did not affect accuracy but significantly increased the reaction time (RT) of detecting face distortions. Importantly, RT was altered only when ES was applied 100ms after visual onset and in face‐selective but not place‐selective sites. Furthermore, ES applied to face‐selective areas decreased the amplitude of visual evoked potentials and high gamma power over this time window. Together, these results suggest that ES of face‐selective regions within a critical time window induces a delay in face perception. These findings support a temporally and spatially specific causal role of face‐selective areas and signify an important link between electrophysiology and behavior in face perception. Hum Brain Mapp 38:2830–2842, 2017. © 2017 Wiley Periodicals, Inc.
Attenuated intrinsic connectivity within cognitive control network among individuals with remitted depression: Temporal stability and association with negative cognitive styles
Authors: Stange Jonathan P. , Bessette Katie L. , Jenkins Lisanne M. , Peters Amy T. , Feldhaus Claudia , Crane Natania A. , Ajilore Olusola , Jacobs Rachel H. , Watkins Edward R. , Langenecker Scott A. 
Published: March 2017

AbstractMany individuals with major depressive disorder (MDD) experience cognitive dysfunction including impaired cognitive control and negative cognitive styles. Functional connectivity magnetic resonance imaging studies of individuals with current MDD have documented altered resting‐state connectivity within the default‐mode network and across networks. However, no studies to date have evaluated the extent to which impaired connectivity within the cognitive control network (CCN) may be present in remitted MDD (rMDD), nor have studies examined the temporal stability of such attenuation over time. This represents a major gap in understanding stable, trait‐like depression risk phenotypes. In this study, resting‐state functional connectivity data were collected from 52 unmedicated young adults with rMDD and 47 demographically matched healthy controls, using three bilateral seeds in the CCN (dorsolateral prefrontal cortex, inferior parietal lobule, and dorsal anterior cingulate cortex). Mean connectivity within the entire CCN was attenuated among individuals with rMDD, was stable and reliable over time, and was most pronounced with the right dorsolateral prefrontal cortex and right inferior parietal lobule, results that were corroborated by supplemental independent component analysis. Attenuated connectivity in rMDD appeared to be specific to the CCN as opposed to representing attenuated within‐network coherence in other networks (e.g., default‐mode, salience). In addition, attenuated connectivity within the CCN mediated relationships between rMDD status and cognitive risk factors for depression, including ruminative brooding, pessimistic attributional style, and negative automatic thoughts. Given that these cognitive markers are known predictors of relapse, these results suggest that attenuated connectivity within the CCN could represent a biomarker for trait phenotypes of depression risk. Hum Brain Mapp 38:2939–2954, 2017. © 2017 Wiley Periodicals, Inc.
Spatio‐angular consistent construction of neonatal diffusion MRI atlases
Authors: Saghafi Behrouz , Kim Jaeil , Chen Geng , Shi Feng , Lin Weili , Yap Pew‐Thian , Shen Dinggang 
Published: March 2017

AbstractAtlases constructed using diffusion‐weighted imaging are important tools for studying human brain development. Atlas construction is in general a two‐step process involving spatial registration and fusion of individual images. The focus of most studies so far has been on improving the accuracy of registration while image fusion is commonly performed using simple averaging, often resulting in fuzzy atlases. In this article, we propose a patch‐based method for diffusion‐weighted (DW) atlas construction. Unlike other atlases that are based on the diffusion tensor model, our atlas is model‐free and generated directly from the diffusion‐weighted images. Instead of independently generating an atlas for each gradient direction and hence neglecting angular image correlation, we propose to construct the atlas by jointly considering DW images of neighboring gradient directions. We employ a group regularization framework where local patches of angularly neighboring images are constrained for consistent spatio‐angular atlas reconstruction. Experimental results confirm that our atlas, constructed for neonatal data, reveals more structural details with higher fractional anisotropy than the atlas generated without angular consistency as well as the average atlas. Also the normalization of test subjects to the proposed atlas results in better alignment of brain structures.Hum Brain Mapp 38:3175–3189, 2017. ©2017 Wiley Periodicals, Inc.
The functional architectures of addition and subtraction: Network discovery using fMRI and DCM
Authors: Yang Yang , Zhong Ning , Friston Karl , Imamura Kazuyuki , Lu Shengfu , Li Mi , Zhou Haiyan , Wang Haiyuan , Li Kuncheng , Hu Bin 
Published: March 2017

AbstractThe neuronal mechanisms underlying arithmetic calculations are not well understood but the differences between mental addition and subtraction could be particularly revealing. Using fMRI and dynamic causal modeling (DCM), this study aimed to identify the distinct neuronal architectures engaged by the cognitive processes of simple addition and subtraction. Our results revealed significantly greater activation during subtraction in regions along the dorsal pathway, including the left inferior frontal gyrus (IFG), middle portion of dorsolateral prefrontal cortex (mDLPFC), and supplementary motor area (SMA), compared with addition. Subsequent analysis of the underlying changes in connectivity – with DCM – revealed a common circuit processing basic (numeric) attributes and the retrieval of arithmetic facts. However, DCM showed that addition was more likely to engage (numeric) retrieval‐based circuits in the left hemisphere, while subtraction tended to draw on (magnitude) processing in bilateral parietal cortex, especially the right intraparietal sulcus (IPS). Our findings endorse previous hypotheses about the differences in strategic implementation, dominant hemisphere, and the neuronal circuits underlying addition and subtraction. Moreover, for simple arithmetic, our connectivity results suggest that subtraction calls on more complex processing than addition: auxiliary phonological, visual, and motor processes, for representing numbers, were engaged by subtraction, relative to addition. Hum Brain Mapp 38:3210–3225, 2017. © 2017 Wiley Periodicals, Inc.
Comparing functional MRI protocols for small, iron‐rich basal ganglia nuclei such as the subthalamic nucleus at 7 T and 3 T
Authors: de Hollander Gilles , Keuken Max C. , van der Zwaag Wietske , Forstmann Birte U. , Trampel Robert 
Published: March 2017

AbstractThe basal ganglia (BG) form a network of subcortical nuclei. Functional magnetic resonance imaging (fMRI) in the BG could provide insight in its functioning and the underlying mechanisms of Deep Brain Stimulation (DBS). However, fMRI of the BG with high specificity is challenging, because the nuclei are small and variable in their anatomical location. High resolution fMRI at field strengths of 7 Tesla (T) could help resolve these challenges to some extent. A set of MR protocols was developed for functional imaging of the BG nuclei at 3 T and 7 T. The protocols were validated using a stop‐signal reaction task (Logan et al. []: J Exp Psychol: Human Percept Perform 10:276–291). Compared with sub‐millimeter 7 T fMRI protocols aimed at cortex, a reduction of echo time and spatial resolution was strictly necessary to obtain robust Blood Oxygen Level Dependent (BOLD) sensitivity in the BG. An fMRI protocol at 3 T with identical resolution to the 7 T showed no robust BOLD sensitivity in any of the BG nuclei. The results suggest that the subthalamic nucleus, as well as the substantia nigra, red nucleus, and the internal and external parts of the globus pallidus show increased activation in failed stop trials compared with successful stop and go trials. Hum Brain Mapp 38:3226–3248, 2017. © 2017 Wiley Periodicals, Inc.
Abnormal frontoparietal synaptic gain mediating the P300 in patients with psychotic disorder and their unaffected relatives
Authors: Díez Álvaro , Ranlund Siri , Pinotsis Dimitris , Calafato Stella , Shaikh Madiha , Hall Mei‐Hua , Walshe Muriel , Nevado Ángel , Friston Karl J. , Adams Rick A. , Bramon Elvira 
Published: March 2017

AbstractThe “dysconnection hypothesis” of psychosis suggests that a disruption of functional integration underlies cognitive deficits and clinical symptoms. Impairments in the P300 potential are well documented in psychosis. Intrinsic (self‐)connectivity in a frontoparietal cortical hierarchy during a P300 experiment was investigated. Dynamic Causal Modeling was used to estimate how evoked activity results from the dynamics of coupled neural populations and how neural coupling changes with the experimental factors. Twenty‐four patients with psychotic disorder, twenty‐four unaffected relatives, and twenty‐five controls underwent EEG recordings during an auditory oddball paradigm. Sixteen frontoparietal network models (including primary auditory, superior parietal, and superior frontal sources) were analyzed and an optimal model of neural coupling, explaining diagnosis and genetic risk effects, as well as their interactions with task condition were identified. The winning model included changes in connectivity at all three hierarchical levels. Patients showed decreased self‐inhibition—that is, increased cortical excitability—in left superior frontal gyrus across task conditions, compared with unaffected participants. Relatives had similar increases in excitability in left superior frontal and right superior parietal sources, and a reversal of the normal synaptic gain changes in response to targets relative to standard tones. It was confirmed that both subjects with psychotic disorder and their relatives show a context‐independent loss of synaptic gain control at the highest hierarchy levels. The relatives also showed abnormal gain modulation responses to task‐relevant stimuli. These may be caused by NMDA‐receptor and/or GABAergic pathologies that change the excitability of superficial pyramidal cells and may be a potential biological marker for psychosis. Hum Brain Mapp 38:3262–3276, 2017. © 2017 Wiley Periodicals, Inc.
A Dynamic Estimation of Obesity Using Nhanes Data: A Pseudo‐Panel Approach
Authors: Saksena Michelle , Maldonado Norman 
Published: March 2017

SummaryIn this analysis, we examine the effect of wages on obesity by constructing pseudo‐panels to conduct a dynamic estimation of Grossman's human capital model. The results indicate that wages have an increasing effect on obesity status. After accounting for past health status, the protective effect of wages commonly disseminated in the literature reverses on obesity status. The results may also indicate possible asymmetric consumption behavior between foods/nutrients that improve diet quality versus those that degrade it. Individuals may be more keen to adhere to prophylactic diet strategies that abate consumption of unhealthy food/nutrients rather than measures which increase healthy nutrient consumption. Additionally, wages have an increasing effect on overall total calories consumed. These findings suggest that higher wage earners may focus their diet efforts on reducing consumption of specific nutrients but compensate by overconsuming other types of nutrients increasing overall calorie intake. Copyright © 2017 John Wiley & Sons, Ltd.
Comparison of the safety of electrotome, Harmonic scalpel, and LigaSure for management of thyroid surgery
Authors: Yang Xiaodong , Cao Jian , Yan Yichao , Liu Fangfang , Li Tao , Han Long , Ye Chunxiang , Zheng Shuying , Wang Shan , Ye Yingjiang , Jiang Kewei 
Published: March 2017

ABSTRACTBackgroundEnergy‐based surgical devices, including electrotome, the Harmonic scalpel, and LigaSure, have been widely applied in thyroid surgery, although a comparison of their safety and efficacy has not been reported yet. In this study, we investigated the feasibility of using hemostatic energy‐based surgical devices during thyroid surgery in a canine model.MethodsTwenty‐four beagle dogs were randomly divided into the following groups: electrotome (30 kW), electrotome (15 kW), the Harmonic scalpel (output level 3), and LigaSure (middle gear). The hemostatic devices were applied on the thyroid surface for 3 seconds and then near the recurrent laryngeal nerve (RLN; distance of 5 mm, 3 mm, or 1 mm) for 3 seconds. Evoked electromyography (EMG) amplitudes were recorded by intraoperative neuromonitoring (IONM). Acute microstructural morphological damage to thyroid tissues and the RLN were evaluated immediately after the procedure by light and electron microscopy.ResultsElectrotome caused a significant decrease in evoked EMG amplitudes when applied at a vertical distance of 1 mm from the RLN, both at 30 kW (1046 ± 404.3 μV vs 153 ± 245.5 μV; p < .001) and 15 kW (1197 ± 589.2 μV vs 986.3 ± 797.3 μV; p = .037), compared with those evoked under normal conditions. Furthermore, distinct acute microstructural morphological changes of the RLNs were observed by light and electron microscopy. However, no significant functional or histological changes were induced by the electrotome at a vertical distance of 5 mm or 3 mm from the RLN. The Harmonic scalpel and LigaSure induced neither marked changes in evoked EMG amplitudes when applied at vertical distances of 5 mm, 3 mm, or 1 mm (all p > .05) nor microstructural morphological changes in the RLNs. The electrotome (15 kW) caused more serious thermal damage to thyroid tissues than that caused by either the Harmonic scalpel or LigaSure (thermal damaged depth: 0.951 ± 0.061 vs 0.756 ± 0.074, p < .001; 0.951 ± 0.061 vs 0.724 ± 0.116, p < .001). Nevertheless, there were no differences between the Harmonic scalpel and LigaSure groups (p = .435).ConclusionLigaSure and the Harmonic scalpel might be safer than electrotome when used in thyroid operations. LigaSure generates less heat than the Harmonic scalpel and electrotome. © 2017 Wiley Periodicals, Inc. Head Neck 39: 1078–1085, 2017
Appointing and Remunerating Insolvency Practitioners in Japan: The Roles of Japanese Courts
Authors: Steele Stacey 
Published: March 2017

AbstractJapanese courts play an important role in appointing and remunerating insolvency practitioners. This article examines the roles of courts on the basis of academic and practitioner literature, judicial decisions and interviews with practitioners and former and current judicial officers. First, the article focuses on the methods used to appoint practitioners and the evolution of the system at the Tokyo District Court, Japan's busiest insolvency jurisdiction. Second, the article examines the courts' roles in reviewing and setting practitioners' remuneration through another case study from the Tokyo District Court. Practices trialled and developed in Tokyo are often adapted for local purposes around Japan. The article argues that the courts' involvement has helped to keep the cost of resolving corporate insolvency in Japan down. The review and setting of remuneration deserves particular attention with the increasing prevalence of pre‐packaged and informal restructuring that prima facie appears to allow for greater freedom to set remuneration as between the practitioner and debtor‐client. The article uses a case study to demonstrate that pre‐packaged restructuring is still influenced by the court, however, arguing that the relationship between the court and practitioners remains important. Finally, the article suggests that changes in Japanese insolvency practice and external factors may require the courts and the profession to revisit approaches to appointing and remunerating practitioners. Copyright © 2017 INSOL International and John Wiley & Sons, Ltd.
Asiaticoside hinders the invasive growth of keloid fibroblasts through inhibition of the GDF‐9/MAPK/Smad pathway
Authors: Wu Xin , Bian Difei , Dou Yannong , Gong Zhunan , Tan Qian , Xia Yufeng , Dai Yue 
Published: March 2017

AbstractHigher expression of growth differentiation factor‐9 (GDF‐9) in keloids compared with hypertrophic scars and normal skin tissues has been reported recently. The present study was performed to investigate the role of GDF‐9 in keloid pathogenesis, and to elucidate its implication for asiaticoside in the keloid management. The data showed that GDF‐9 could enhance the proliferation, migration, and invasion of keloid fibroblasts (KFs), while it only slightly elevated collagen expression, indicating that the effect of GDF‐9 was opposite to that of TGF‐β1. The bioactivity difference between GDF‐9 and TGF‐β1 could be explained by the different phosphorylated sites on the downstream Smad2/3. Moreover, asiaticoside could inhibit GDF‐9‐induced activation of MAPKs and Smad pathway in KFs. In conclusion, GDF‐9 enhanced the invasive growth of KFs, which was achieved by phosphorylation of Smad 2/3 at the linker region through activation of MAPKs pathway. Asiaticoside hindered the invasive growth of KFs by inhibiting the GDF‐9/MAPK/Smad pathway.
Effect of temperature on lysosomal enzyme activity during preparation and storage of dried blood spots
Authors: Supriya Manjunath , De Tanima , Christopher Rita 
Published: March 2017

BackgroundThe use of dried blood spots (DBS) for the assay of lysosomal enzymes has facilitated the implementation of pilot studies for newborn screening for lysosomal storage disorders in various developed countries. The aim of the study was to determine the influence of ambient temperature during DBS preparation and storage on lysosomal enzyme activity in a developing, tropical country.MethodsBlood samples from 12 healthy subjects collected on a S&S 903 filter paper were dried and stored at different temperatures for different periods of time. Activities of five lysosomal enzymes (acid α‐glucosidase, acid α‐galactosidase, acid β‐glucocerebrosidase, acid sphingomyelinase, and galactocerebrosidase) were determined by tandem mass spectrometric and fluorimetric (acid α‐glucosidase and acid β‐glucocerebrosidase only) assays.ResultsThe mean activities of all five enzymes decreased significantly when DBS was dried at temperatures above 24°C (P<.0001). DBS stored at 4°C, 24°C, 30°C, 37°C, and 45°C for 10 days and more, also showed significant reduction in activities of all five enzymes (P<.0001).ConclusionThe results highlight the importance of maintaining the correct ambient temperature during DBS preparation and storage to avoid false positive results when screening for lysosomal storage disorders.
The effect of microwave on the interaction of flavour compounds with G‐actin from grass carp (Catenopharyngodon idella)
Authors: Lou Xiaowei , Yang Qiuli , Sun Yangying , Pan Daodong , Cao Jinxuan 
Published: March 2017

AbstractBACKGROUNDIn order to investigate the influence of non‐thermal effects of microwaves on the flavour of fish and meat products, the G‐actin of grass carp in ice baths was exposed to different microwave powers (0, 100, 300 or 500 W); the surface hydrophobicity, sulfhydryl contents, secondary structures and adsorption capacity of G‐actin to ketones were determined.RESULTSAs microwave power increased from 0 to 300 W, the surface hydrophobicity, total and reactive sulfhydryls increased; α‐helix, β‐sheet and random coil fractions turned into β‐turn fractions. As microwave power increased from 300 to 500 W, however, hydrophobicity and sulfhydryl contents decreased; β‐turn and random coil fractions turned into α‐helix and β‐sheet fractions. The tendencies of adsorbed capacity of ketones were similar to hydrophobicity and sulfhydryl contents.CONCLUSIONThe increased adsorbing of ketones could be attributed to the unfolding of secondary structures by revealing new binding sites, including thiol groups and hydrophobic binding sites. The decreased binding capacity was related to the refolding and aggregation of protein. The results suggested that microwave powers had obvious effects on the flavour retention and proteins structures in muscle foods. © 2017 Society of Chemical Industry