bluuebunny/crossref_metadata_2025 huggingface dataset:
APPLICATION OF EMPIRICAL MODE DECOMPOSITION (EMD) FOR AUTOMATED DETECTION OF EPILEPSY USING EEG SIGNALS
Authors: MARTIS ROSHAN JOY , ACHARYA U. RAJENDRA , TAN JEN HONG , PETZNICK ANDREA , YANTI RATNA , CHUA CHUA KUANG , NG E. Y. K. , TONG LOUIS
Published: September 2012

Epilepsy is a global disease with considerable incidence due to recurrent unprovoked seizures. These seizures can be noninvasively diagnosed using electroencephalogram (EEG), a measure of neuronal electrical activity in brain recorded along scalp. EEG is highly nonlinear, nonstationary and non-Gaussian in nature. Nonlinear adaptive models such as empirical mode decomposition (EMD) provide intuitive understanding of information present in these signals. In this study a novel methodology is proposed to automatically classify EEG of normal, inter-ictal and ictal subjects using EMD decomposition. EEG decomposition using EMD yields few intrinsic mode functions (IMF), which are amplitude and frequency modulated (AM and FM) waves. Hilbert transform of these IMF provides AM and FM frequencies. Features such as spectral peaks, spectral entropy and spectral energy in each IMF are extracted and fed to decision tree classifier for automated diagnosis. In this work, we have compared the performance of classification using two types of decision trees (i) classification and regression tree (CART) and (ii) C4.5. We have obtained the highest average accuracy of 95.33%, average sensitivity of 98%, and average specificity of 97% using C4.5 decision tree classifier. The developed methodology is ready for clinical validation on large databases and can be deployed for mass screening.
GENERALIZED PRESENTATIONS OF INFINITE GROUPS, IN PARTICULAR OF Aut(Fω)
Authors: BOGOPOLSKI OLEG , SINGHOF WILHELM
Published: September 2012

We develop a theory of generalized presentations of groups and give a generalized presentation of the automorphism group of the free group of countable rank, Aut (Fω).
AN EXAMPLE OF A SUBGROUP SEPARABLE BUT NOT CONJUGACY SEPARABLE GROUP
Authors: CHAGAS S. C. , DE OLIVEIRA K. S. , ZALESSKII P. A.
Published: September 2012

We give an example of a conjugacy separable, but not subgroup separable group. It is an adaptation of an example of Tavgen and the third author from [Closed orbits and finite approximability with respect to conjugacy of free amalgamated products, Math. Notes58 (1995) 1042–1048] to a theorem of Raptis [On finiteness conditions of certain graphs of groups, Internat. J. Algebra Comput.5 (1995) 719–724].
EFFICIENT ALGORITHMS FOR HIGHLY COMPRESSED DATA: THE WORD PROBLEM IN HIGMAN'S GROUP IS IN P
Authors: DIEKERT VOLKER , LAUN JÜRN , USHAKOV ALEXANDER
Published: September 2012

Power circuits are data structures which support efficient algorithms for highly compressed integers. Using this new data structure it has been shown recently by Myasnikov, Ushakov and Won that the Word Problem of the one-relator Baumslag group is in P. Before that the best known upper bound was non-elementary. In the present paper we provide new results for power circuits and we give new applications in algorithmic algebra and algorithmic group theory: (1) We define a modified reduction procedure on power circuits which runs in quadratic time, thereby improving the known cubic time complexity. The improvement is crucial for our other results. (2) We improve the complexity of the Word Problem for the Baumslag group to cubic time, thereby providing the first practical algorithm for that problem. (The algorithm has been implemented and is available in the CRAG library.) (3) The main result is that the Word Problem of Higman's group is decidable in polynomial time. The situation for Higman's group is more complicated than for the Baumslag group and forced us to advance the theory of power circuits.
THE TRAVELING SALESMAN PROBLEM FOR LINES AND RAYS IN THE PLANE
Authors: DUMITRESCU ADRIAN
Published: September 2012

In the Euclidean TSP with neighborhoods (TSPN), we are given a collection of n regions (neighborhoods) and we seek a shortest tour that visits each region. In the path variant, we seek a shortest path that visits each region. We present several linear-time approximation algorithms with improved ratios for these problems for two cases of neighborhoods that are (infinite) lines, and respectively, (half-infinite) rays. Along the way we derive a tight bound on the minimum perimeter of a rectangle enclosing an open curve of length L.
NEW ICA ALGORITHMS BASED ON SPECIAL LINEAR GROUP
Authors: TAN HANG , HUANG XIANHE , TANG YING , TAN HUACHUN
Published: September 2012

Unlike the traditional independent component analysis (ICA) algorithms and some recently emerging linear ICA algorithms that search for solutions in the space of general matrices or orthogonal matrices, in this paper we propose two new methods which only search for solutions in the space of the matrices with unitary determinant and without whitening. The new algorithms are based on the special linear group SL(n). In order to achieve our target, we first provide a representation theory for any matrix in SL(n), which only simply uses the product of multiple exponentials of traceless matrices. Based on the matrix representation theory, two novel ICA algorithms are developed along with simple analysis on their equilibrium points. Moreover, we apply our methods to the classical problem of signal separation. The experimental results indicate that the superior convergence of our proposed algorithms, which can be expected as two viable alternatives to the ICA algorithms available in publications.
Digging for drug facts
Authors: Savage Neil
Published: September 2012

With the right approach, data mining can discover unexpected side effects and drug interactions.
The foresight saga, redux
Authors: Neumann Peter G.
Published: September 2012

Short-term thinking is the enemy of the long-term future.
Future Tense: Fermi's paradox and the end of the universe
Authors: Landis Geoffrey A.
Published: September 2012

From the intersection of computational science and technological speculation, with boundaries limited only by our ability to imagine what could be.

How to colonize the galaxy, one electron spin state at a time.
User-level data center tomography
Authors: Twigg Neil Alexander , Fayed Marwan , Perkins Colin , Pezaros Dimitrios , Tso Posco
Published: September 2012

Measurement and inference in data centers present a set of opportunities and challenges distinct from the Internet domain. Existing toolsets may be perturbed or be mislead by issues related to virtualization. Yet, while equally confronted by scale, data centers are relatively homogenous and symmetric. We believe these may be attributes to be exploited. However, data is required to better evaluate our hypotheses. Therefore, we introduce our efforts to gather data using a single framework from which we can launch tests of our choosing. Our observations reinforce recent claims, but indicate changes in the network. They also reveal additional obfuscations stemming from virtualization.
Vitamin C for your smartphone
Authors: Wählisch Matthias , Trapp Sebastian , Schiller Jochen , Jochheim Benjamin , Nolte Theodor , Schmidt Thomas C. , Ugus Osman , Westhoff Dirk , Kutscher Martin , Küster Matthias , Keil Christian , Schönfelder Jochen
Published: September 2012

Smartphones are popular attack targets, but usually too weak in applying common protection concepts. SKIMS designs and implements a cooperative, cross-layer security system for mobile devices. Detection mechanisms as well as a proactive and reactive defense of attacks are core components of this project. In this demo, we show a comprehensive proof-of-concept of our approaches, which include entropy-based malware detection, a mobile honeypot, and spontaneous, socio-inspired trust establishment.
MultiNet
Authors: Brown Anthony , Mortier Richard , Rodden Tom
Published: September 2012

This demo presents
MultiNet
, a novel method for joining devices to a domestic Wi-Fi network. MultiNet dynamically reconfigures the network to accept each device, rather than configuring each device to fit the network as is the norm. It does so by assuming that each device is pre-configured with a cryptographically generated WPA2 network SSID/passphrase pair, and then providing a lightweight interaction through which the user creates a new network for each device. This approach makes securely adding devices to a wireless network straightforward without compromising security or burdening the user, and maintaining backward compatibility with existing deployed standards and protocols.

The demo deploys a MultiNet Access Point (AP) and a number of Wi-Fi enabled consumer devices to allow viewers to dynamically construct and deconstruct the network via the MultiNet controller currently implemented as an app on an Android phone (Figure 1). The code for MultiNet is publicly available under open-source licenses.
Supporting network evolution and incremental deployment with XIA
Authors: Grandl Robert , Han Dongsu , Lee Suk-Bok , Lim Hyeontaek , Machado Michel , Mukerjee Matthew , Naylor David
Published: September 2012

eXpressive Internet Architecture (XIA) [1] is an architecture that natively supports multiple communication types and allows networks to evolve their abstractions and functionality to accommodate new styles of communication over time. XIA embeds an elegant mechanism for handling unforeseen communication types for legacy routers.

In this demonstration, we show that XIA overcomes three key barriers in network evolution (outlined below) by (1) allowing end-hosts and applications to start using new communication types (e.g., service and content) before the network supports them, (2) ensuring that upgrading a subset of routers to support new functionalities immediately benefits applications, and (3) using the same mechanisms we employ for 1 and 2 to incrementally deploy XIA in IP networks.
Fs-PGBR
Authors: Mineraud Julien , Balasubramaniam Sasitharan , Kangasharju Jussi , Donnelly William
Published: September 2012

This paper proposes an improved version of a fully distributed routing protocol, that is applicable for cloud computing infrastructure. Simulation results shows the protocol is ideal for discovering cloud services in a scalable manner with minimum latency.
Optimizing cost and performance for content multihoming
Authors: Liu Hongqiang Harry , Wang Ye , Yang Yang Richard , Wang Hao , Tian Chen
Published: September 2012

Many large content publishers use multiple content distribution networks to deliver their content, and many commercial systems have become available to help a broader set of content publishers to benefit from using multiple distribution networks, which we refer to as
content multihoming
. In this paper, we conduct the first systematic study on optimizing content multihoming, by introducing novel algorithms to optimize both performance and cost for content multihoming. In particular, we design a novel, efficient algorithm to compute assignments of content objects to content distribution networks for content publishers, considering both cost and performance. We also design a novel, lightweight client adaptation algorithm executing at individual content viewers to achieve scalable, fine-grained, fast online adaptation to optimize the quality of experience (QoE) for individual viewers. We prove the optimality of our optimization algorithms and conduct systematic, extensive evaluations, using real charging data, content viewer demands, and performance data, to demonstrate the effectiveness of our algorithms. We show that our content multihoming algorithms reduce publishing cost by up to 40%. Our client algorithm executing in browsers reduces viewer QoE degradation by 51%.
Inferring who-is-who in the Twitter social network
Authors: Sharma Naveen Kumar , Ghosh Saptarshi , Benevenuto Fabricio , Ganguly Niloy , Gummadi Krishna
Published: September 2012

In this paper, we design and evaluate a novel who-is-who service for inferring attributes that characterize individual Twitter users. Our methodology exploits the Lists feature, which allows a user to group other users who tend to tweet on a topic that is of interest to her, and follow their collective tweets. Our key insight is that the List meta-data (names and descriptions) provides valuable semantic cues about who the users included in the Lists are, including their topics of expertise and how they are perceived by the public. Thus, we can infer a user's expertise by analyzing the meta-data of crowdsourced Lists that contain the user. We show that our methodology can accurately and comprehensively infer attributes of millions of Twitter users, including a vast majority of Twitter's influential users (based on ranking metrics like number of followers). Our work provides a foundation for building better search and recommendation services on Twitter.
BMP4 is a novel paracrine inhibitor of liver regeneration
Authors: Do Nhue , Zhao Rong , Ray Kevin , Ho Karen , Dib Martin , Ren Xianghui , Kuzontkoski Paula , Terwilliger Ernest , Karp Seth J.
Published: September 2012

Transforming growth factor (TGF)-β family members exert strong effects on restoration of liver mass after injury. Bone morphogenetic proteins (BMPs) are members of the TGF-β family and are found in the liver, suggesting that these proteins may play a role in liver regeneration. We examined BMP signaling in the liver during hepatectomy. We found that BMP4 is constitutively expressed in the peribiliary stroma and endothelial cells of the liver and that expression is decreased after hepatectomy. Mice driven to maintain BMP4 expression in the liver display inhibited hepatocyte proliferation and restoration of liver mass after hepatectomy, suggesting that reduced BMP4 is necessary for normal regeneration. Consistent with this finding, hepatocyte-specific deletion of the BMP receptor activin receptor-like kinase 3 (Alk3) enhances regeneration and reduces phosphorylation of SMAD1/5/8, a transducer of BMP signaling. In contrast to experiments in wild-type mice, maintaining BMP4 levels has no effect on liver regeneration in hepatocyte-specific Alk3 null mice, providing evidence that BMP4 signals through Alk3 to inhibit liver regeneration. Consistent with these findings, the BMP4 antagonist Noggin enhances regeneration. Furthermore, high-dose BMP4 inhibits proliferation of primary hepatocytes and HepG2 cells in culture. These findings elucidate a new, potentially clinically relevant paradigm in which a constitutively expressed paracrine inhibitory factor plays a critical role in liver regeneration.
Linking tumor-associated macrophages, inflammation, and intestinal tumorigenesis: role of MCP-1
Authors: McClellan Jamie L. , Davis J. Mark , Steiner Jennifer L. , Enos Reilly T. , Jung Seung H. , Carson James A. , Pena Maria M. , Carnevale Kevin A. , Berger Franklin G. , Murphy E. Angela
Published: September 2012

Tumor-associated macrophages are associated with poor prognosis in certain cancers. Monocyte chemoattractant protein 1 (MCP-1) is thought to be the most important chemokine for recruitment of macrophages to the tumor microenvironment. However, its role on tumorigenesis in a genetic mouse model of colon cancer has not been explored. We examined the role of MCP-1 on tumor-associated macrophages, inflammation, and intestinal tumorigenesis. Male Apc Min/+, Apc Min/+/MCP-1−/− or wild-type mice were euthanized at 18 wk of age and intestines were analyzed for polyp burden, apoptosis, proliferation, β-catenin, macrophage number and phenotype, markers for cytotoxic T lymphocytes and regulatory T cells, and inflammatory mediators. MCP-1 deficiency decreased overall polyp number by 20% and specifically large polyp number by 45% ( P < 0.05). This was consistent with an increase in apoptotic cells ( P < 0.05), but there was no change detected in proliferation or β-catenin. MCP-1 deficiency decreased F4/80-positive cells in both the polyp tissue and surrounding intestinal tissue ( P < 0.05) as well as expression of markers associated with M1 (IL-12 and IL-23) and M2 macrophages (IL-13, CD206, TGF-β, and CCL17) ( P < 0.05). MCP-1 knockout was also associated with increased cytotoxic T lymphocytes and decreased regulatory T cells ( P < 0.05). In addition, MCP-1−/− offset the increased mRNA expression of IL-1β and IL-6 in intestinal tissue and IL-1β and TNF-α in polyp tissue ( P < 0.05), and prevented the decrease in SOCS1 expression ( P < 0.05). We demonstrate that MCP-1 is an important mediator of tumor growth and immune regulation that may serve as an important biomarker and/or therapeutic target in colon cancer.
Cardiac sympathetic imaging withmIBG in cirrhosis and portal hypertension: relation to autonomic and cardiac function
Authors: Møller Søren , Mortensen Christian , Bendtsen Flemming , Jensen Lars T. , Gøtze Jens P. , Madsen Jan L.
Published: September 2012

Autonomic and cardiac dysfunction is frequent in cirrhosis and includes increased sympathetic nervous activity, impaired heart rate variability (HRV), and baroreflex sensitivity (BRS). Quantified123I-metaiodobenzylguanidine ( mIBG) scintigraphy reflects cardiac noradrenaline uptake, and in patients with cardiac failure it predicts outcome. In this study, we aimed to investigate cardiac sympathetic neuronal function in cirrhosis by mIBG scintigraphy in relation to cardiovascular function. Ten patients with alcoholic cirrhosis and 10 age- and sex-matched healthy controls participated in the study. Heart/mediastinum (H/M) ratios of mIBG uptake were calculated 15 and 230 min after intravenous injection of mIBG. Furthermore, washout rate (WOR) of mIBG was calculated. The patients underwent a liver vein catheterization with determination of splanchnic and systemic hemodynamics and measurement of HRV and BRS. mIBG-scintigraphy revealed significantly increased WOR in patients with cirrhosis compared with controls ( P < 0.005), whereas H/M uptakes were equal in the groups. Forty percent of the patients had reduced uptake of mIBG in the infero-lateral segment of the left ventricle. WOR correlated significantly with central circulation time, an estimate of central hypovolemia ( r = −0.64, P < 0.05) and frequency-corrected QTFinterval ( r = 0.71, P = 0.01). Patients with cirrhosis had significantly decreased HRV and BRS correlating with indicators of abnormal cathecholamine uptake by mIBG although the catecholamine level was normal in the patients. In conclusion, in alcoholic cirrhosis, mIBG scintigraphy reveals autonomic dysfunction and impaired myocardial distribution of sympathetic nervous activity. It is associated to indicators of central hypovolemia, QT interval, and decreased HRV and BRS. Measurement of myocardial catecholamine uptake by mIBG may add important information on autonomic and cardiac dysfunction in cirrhosis.
Tissue remodeling in eosinophilic esophagitis
Authors: Cheng Edaire , Souza Rhonda F. , Spechler Stuart J.
Published: September 2012

Eosinophilic esophagitis (EoE) is a recently recognized, immune-mediated disease characterized clinically by symptoms of esophageal dysfunction and histologically by eosinophil-predominant inflammation. The chronic esophageal eosinophilia of EoE is associated with tissue remodeling that includes epithelial hyperplasia, subepithelial fibrosis, and hypertrophy of esophageal smooth muscle. This remodeling causes the esophageal rings and strictures that frequently complicate EoE and underlies the mucosal fragility that predisposes to painful mucosal tears in the EoE esophagus. The pathogenesis of tissue remodeling in EoE is not completely understood, but emerging studies suggest that secretory products of eosinophils and mast cells, as well as cytokines produced by other inflammatory cells, epithelial cells, and stromal cells in the esophagus, all contribute to the process. Interleukin (IL)-4 and IL-13, Th2 cytokines overproduced in allergic disorders, have direct profibrotic and remodeling effects in EoE. The EoE esophagus exhibits increased expression of transforming growth factor (TGF)-β1, which is a potent activator of fibroblasts and a strong inducer of epithelial-mesenchymal transition. In addition, IL-4, IL-13, and TGF-β all have a role in regulating periostin, an extracellular matrix protein that might influence remodeling by acting as a ligand for integrins, by its effects on eosinophils or by activating fibrogenic genes in the esophagus. Presently, few treatments have been shown to affect the tissue remodeling that causes EoE complications. This report reviews the potential roles of fibroblasts, eosinophils, mast cells, and profibrotic cytokines in esophageal remodeling in EoE and identifies potential targets for future therapies that might prevent EoE complications.
Sustained high-altitude hypoxia increases cerebral oxygen metabolism
Authors: Smith Zachary M. , Krizay Erin , Guo Jia , Shin David D. , Scadeng Miriam , Dubowitz David J.
Published: September 2012

Acute mountain sickness (AMS) is a common condition occurring within hours of rapid exposure to high altitude. Despite its frequent occurrence, the pathophysiological mechanisms that underlie the condition remain poorly understood. We investigated the role of cerebral oxygen metabolism (CMRO2) in AMS. The purpose of this study was to test 1) if CMRO2 changes in response to hypoxia, and 2) if there is a difference in how individuals adapt to oxygen metabolic changes that may determine who develops AMS and who does not. Twenty-six normal human subjects were recruited into two groups based on Lake Louise AMS score (LLS): those with no AMS (LLS ≤ 2), and those with unambiguous AMS (LLS ≥ 5). [Subjects with intermediate scores (LLS 3–4) were not included.] CMRO2 was calculated from cerebral blood flow and arterial-venous difference in O2 content. Cerebral blood flow was measured using arterial spin labeling MRI; venous O2 saturation was calculated from the MRI of transverse relaxation in the superior sagittal sinus. Arterial O2 saturation was measured via pulse oximeter. Measurements were made during normoxia and after 2-day high-altitude exposure at 3,800 m. In all subjects, CMRO2 increased with sustained high-altitude hypoxia [1.54 (0.37) to 1.82 (0.49) μmol·g−1·min−1, n = 26, P = 0.045]. There was no significant difference in CMRO2 between AMS and no-AMS groups. End-tidal Pco2 was significantly reduced during hypoxia. Low arterial Pco2 is known to increase neural excitability, and we hypothesize that the low arterial Pco2 resulting from ventilatory acclimatization causes the observed increase in CMRO2.
Respiratory timing and variability during sleep in children with sleep-disordered breathing
Authors: Immanuel Sarah A. , Pamula Yvonne , Kohler Mark , Martin James , Kennedy Declan , Kabir Muammar M. , Saint David A. , Baumert Mathias
Published: September 2012

Sleep-disordered breathing (SDB) in children is assessed by quantification of hypopnea and apnea events. Little is known, however, about respiratory timing and breath-to-breath variability during sleep. The aim of this study was to investigate respiratory parameters across sleep stages in children with SDB before and after treatment compared with healthy children. Overnight polysomnography (PSG) was conducted in 40 children with SDB prior to and 6 mo following adenotonsillectomy. For comparison, a control group of 40 healthy sex- and age-matched children underwent two PSGs at equivalent time points but without intervention. The following variables were measured breath by breath during obstruction-free periods in stage 2 nonrapid eye movement (NREM), stage 4 NREM, and REM sleep: inspiratory time (Ti), expiratory time (Te), total time (Ttotal), inspiratory duty cycle (DC; =Ti/Ttotal), respiratory frequency (fR), and SD of the parameters Ti, Te, fR, and DC. Variability in waveform morphology was also computed using the residue of respiratory patterns. The severity of SDB was relatively mild in the study cohort (obstructive apnea hypopnea index: baseline, 5.1 ± 9.4 vs. 0.1 ± 0.2, P < 0.001; follow-up, 0.3 ± 0.3 vs. 0.8 ± 1.0, P < 0.01). Compared with healthy controls, children with SDB showed significantly longer Ti and Te and a lower fR at the baseline study. These differences were not significant after adenotonsillectomy. Sleep stages were associated with significant differences in all of the respiratory measures in both groups of children. In conclusion, children with relatively mild SDB showed prolonged inspiration and expiration indicative of chronic narrowing of the upper airway. Treatment of SDB normalizes respiratory timing. Documentation of these parameters may aid in both understanding and management of children with SDB.
The effects of phosphate and acidosis on regulated thin-filament velocity in an in vitro motility assay
Authors: Debold Edward P. , Longyear Thomas J. , Turner Matthew A.
Published: September 2012

Muscle fatigue from intense contractile activity is thought to result, in large part, from the accumulation of inorganic phosphate (Pi) and hydrogen ions (H+) acting to directly inhibit the function of the contractile proteins; however, the molecular basis of this process remain unclear. We used an in vitro motility assay and determined the effects of elevated H+and Pion the ability of myosin to bind to and translocate regulated actin filaments (RTF) to gain novel insights into the molecular basis of fatigue. At saturating Ca++, acidosis depressed regulated filament velocity ( VRTF) by ∼90% (6.2 ± 0.3 vs. 0.5 ± 0.2 μm/s at pH 7.4 and 6.5, respectively). However, the addition of 30 mM Picaused VRTFto increase fivefold, from 0.5 ± 0.2 to 2.6 ± 0.3 μm/s at pH 6.5. Similarly, at all subsaturating Ca++levels, acidosis slowed VRTF, but the addition of Pisignificantly attenuated this effect. We also manipulated the [ADP] in addition to the [Pi] to probe which specific step(s) of cross-bridge cycle of myosin is affected by elevated H+. The findings are consistent with acidosis slowing the isomerization step between two actomyosin ADP-bound states. Because the state before this isomerization is most vulnerable to Pirebinding, and the associated detachment from actin, this finding may also explain the Pi-induced enhancement of VRTFat low pH. These results therefore may provide a molecular basis for a significant portion of the loss of shortening velocity and possibly muscular power during fatigue.
Effects of endurance exercise training, metformin, and their combination on adipose tissue leptin and IL-10 secretion in OLETF rats
Authors: Jenkins Nathan T. , Padilla Jaume , Arce-Esquivel Arturo A. , Bayless David S. , Martin Jeffrey S. , Leidy Heather J. , Booth Frank W. , Rector R. Scott , Laughlin M. Harold
Published: September 2012

Adipose tissue inflammation plays a role in cardiovascular (CV) and metabolic diseases associated with obesity, insulin resistance, and type 2 diabetes mellitus (T2DM). The interactive effects of exercise training and metformin, two first-line T2DM treatments, on adipose tissue inflammation are not known. Using the hyperphagic, obese, insulin-resistant Otsuka Long-Evans Tokushima Fatty (OLETF) rat model, we tested the hypothesis that treadmill training, metformin, or a combination of these reduces the secretion of proinflammatory cytokines from adipose tissue. Compared with Long-Evans Tokushima Otsuka (LETO) control rats (L-Sed), sedentary OLETF (O-Sed) animals secreted significantly greater amounts of leptin from retroperitoneal adipose tissue. Conversely, secretion of interleukin (IL)-10 by O-Sed adipose tissue was lower than that in L-Sed animals. Examination of leptin and IL-10 secretion from adipose tissue in OLETF groups treated with endurance exercise training (O-EndEx), metformin treatment (O-Met), and a combination of these (O-E+M) from 20 to 32 wk of age indicated that 1) leptin secretion from adipose tissue was reduced in O-Met and O-E+M, but not O-EndEx animals; 2) adipose tissue IL-10 secretion was increased in O-EndEx and O-E+M but not in O-Met animals; and 3) only the combined treatment (O-E+M) displayed both a reduction in leptin secretion and an increase in IL-10 secretion. Leptin and IL-10 concentrations in adipose tissue–conditioned buffers were correlated with their plasma concentrations, adipocyte diameters, and total adiposity. Overall, this study indicates that exercise training and metformin have additive influences on adipose tissue secretion and plasma concentrations of leptin and IL-10.
Effects of aerobic and/or resistance training on body mass and fat mass in overweight or obese adults
Authors: Willis Leslie H. , Slentz Cris A. , Bateman Lori A. , Shields A. Tamlyn , Piner Lucy W. , Bales Connie W. , Houmard Joseph A. , Kraus William E.
Published: September 2012

Recent guidelines on exercise for weight loss and weight maintenance include resistance training as part of the exercise prescription. Yet few studies have compared the effects of similar amounts of aerobic and resistance training on body mass and fat mass in overweight adults. STRRIDE AT/RT, a randomized trial, compared aerobic training, resistance training, and a combination of the two to determine the optimal mode of exercise for obesity reduction. Participants were 119 sedentary, overweight or obese adults who were randomized to one of three 8-mo exercise protocols: 1) RT: resistance training, 2) AT: aerobic training, and 3) AT/RT: aerobic and resistance training (combination of AT and RT). Primary outcomes included total body mass, fat mass, and lean body mass. The AT and AT/RT groups reduced total body mass and fat mass more than RT ( P < 0.05), but they were not different from each other. RT and AT/RT increased lean body mass more than AT ( P < 0.05). While requiring double the time commitment, a program of combined AT and RT did not result in significantly more fat mass or body mass reductions over AT alone. Balancing time commitments against health benefits, it appears that AT is the optimal mode of exercise for reducing fat mass and body mass, while a program including RT is needed for increasing lean mass in middle-aged, overweight/obese individuals.
Validity of combining heart rate and uniaxial acceleration to measure free-living physical activity energy expenditure in young men
Authors: Villars C. , Bergouignan A. , Dugas J. , Antoun E. , Schoeller D. A. , Roth H. , Maingon A. C. , Lefai E. , Blanc S. , Simon C.
Published: September 2012

Combining accelerometry (ACC) with heart rate (HR) monitoring is thought to improve activity energy expenditure (AEE) estimations compared with ACC alone to evaluate the validity of ACC and HR used alone or combined. The purpose of this study was to estimate AEE in free-living conditions compared with doubly labeled water (DLW). Ten-day free-living AEE was measured by a DLW protocol in 35 18- to 55-yr-old men (11 lean active; 12 lean sedentary; 12 overweight sedentary) wearing an Actiheart (combining ACC and HR) and a RT3 accelerometer. AEE was estimated using group or individual calibration of the HR/AEE relationship, based on an exercise-tolerance test. In a subset ( n = 21), AEE changes (ΔAEE) were measured after 1 mo of detraining (active subjects) or an 8-wk training (sedentary subjects). Actiheart-combined ACC/HR estimates were more accurate than estimates from HR or ACC alone. Accuracy of the Actiheart group-calibrated ACC/HR estimates was modest [intraclass correlation coefficient (ICC) = 0.62], with no bias but high root mean square error (RMSE) and limits of agreement (LOA). The mean bias of the estimates was reduced by one-third, like RMSE and LOA, by individual calibration (ICC = 0.81). Contrasting with group-calibrated estimates, the Actiheart individual-calibrated ACC/HR estimates explained 40% of the variance of the DLW-ΔAEE (ICC = 0.63). This study supports a good level of agreement between the Actiheart ACC/HR estimates and DLW-measured AEE in lean and overweight men with varying fitness levels. Individual calibration of the HR/AEE relationship is necessary for AEE estimations at an individual level rather than at group scale and for ΔAEE evaluation.
Frequency distribution of causal connectivity in rat sensorimotor network: resting-state fMRI analyses
Authors: Shim Woo H. , Baek Kwangyeol , Kim Jeong Kon , Chae Yongwook , Suh Ji-Yeon , Rosen Bruce R. , Jeong Jaeseung , Kim Young R.
Published: September 2012

Resting-state functional MRI (fMRI) has emerged as an important method for assessing neural networks, enabling extensive connectivity analyses between multiple brain regions. Among the analysis techniques proposed, partial directed coherence (PDC) provides a promising tool to unveil causal connectivity networks in the frequency domain. Using the MRI time series obtained from the rat sensorimotor system, we applied PDC analysis to determine the frequency-dependent causality networks. In particular, we compared in vivo and postmortem conditions to establish the statistical significance of directional PDC values. Our results demonstrate that two distinctive frequency populations drive the causality networks in rat; significant, high-frequency causal connections clustered in the range of 0.2–0.4 Hz, and the frequently documented low-frequency connections <0.15 Hz. Frequency-dependence and directionality of the causal connection are characteristic between sensorimotor regions, implying the functional role of frequency bands to transport specific resting-state signals. In particular, whereas both intra- and interhemispheric causal connections between heterologous sensorimotor regions are robust over all frequency levels, the bilaterally homologous regions are interhemispherically linked mostly via low-frequency components. We also discovered a significant, frequency-independent, unidirectional connection from motor cortex to thalamus, indicating dominant cortical inputs to the thalamus in the absence of external stimuli. Additionally, to address factors underlying the measurement error, we performed signal simulations and revealed that the interactive MRI system noise alone is a likely source of the inaccurate PDC values. This work demonstrates technical basis for the PDC analysis of resting-state fMRI time series and the presence of frequency-dependent causality networks in the sensorimotor system.
Effects of spatiotemporal stimulus properties on spike timing correlations in owl monkey primary somatosensory cortex
Authors: Reed Jamie L. , Pouget Pierre , Qi Hui-Xin , Zhou Zhiyi , Bernard Melanie R. , Burish Mark J. , Kaas Jon H.
Published: September 2012

The correlated discharges of cortical neurons in primary somatosensory cortex are a potential source of information about somatosensory stimuli. One aspect of neuronal correlations that has not been well studied is how the spatiotemporal properties of tactile stimuli affect the presence and magnitude of correlations. We presented single- and dual-point stimuli with varying spatiotemporal relationships to the hands of three anesthetized owl monkeys and recorded neuronal activity from 100-electrode arrays implanted in primary somatosensory cortex. Correlation magnitudes derived from joint peristimulus time histogram (JPSTH) analysis of single neuron pairs were used to determine the level of spike timing correlations under selected spatiotemporal stimulus conditions. Correlated activities between neuron pairs were commonly observed, and the proportions of correlated pairs tended to decrease with distance between the recorded neurons. Distance between stimulus sites also affected correlations. When stimuli were presented simultaneously at two sites, ∼37% of the recorded neuron pairs showed significant correlations when adjacent phalanges were stimulated, and ∼21% of the pairs were significantly correlated when nonadjacent digits were stimulated. Spatial proximity of paired stimuli also increased the average correlation magnitude. Stimulus onset asynchronies in the paired stimuli had small effects on the correlation magnitude. These results show that correlated discharges between neurons at the first level of cortical processing provide information about the relative locations of two stimuli on the hand.
Coding of digit displacement by cell spiking and network oscillations in the monkey sensorimotor cortex
Authors: Witham Claire L. , Baker Stuart N.
Published: September 2012

β-Band oscillations occur in motor and somatosensory cortices and muscle activity. Oscillations appear most strongly after movements, suggesting that they may represent or probe the limb's final sensory state. We tested this idea by training two macaque monkeys to perform a finger flexion to one of four displacements, which was then held for 2 s without visual feedback of absolute displacement. Local field potential (LFP) and single unit spiking were recorded from the rostral and caudal primary motor cortex and parietal areas 3a, 3b, 2, and 5. Information theoretic analysis determined how well unit firing rate or the power of LFP oscillations coded finger displacement. All areas encoded significant information about finger displacement after the movement into target, both in β-band (∼20 Hz) oscillatory activity and unit firing rate. On average, the information carried by unit firing was greater (0.07 bits) and peaked earlier (0.73 s after peak velocity) than that by LFP β-oscillations (0.05 bits and 0.95 s). However, there was considerable heterogeneity among units: some cells did not encode maximal information until midway through the holding phase. In 30% of cells, information in rate lagged information in LFP oscillations recorded at the same site. Finger displacement may be represented in the cortex in multiple ways. Coding the digit configuration immediately after a movement probably relies on nonoscillatory feedback, or efference copy. With increasing delay after movement cessation, oscillatory processing may also play a part.
Neural coding of taste by simultaneously recorded cells in the nucleus of the solitary tract of the rat
Authors: Rosen Andrew M. , Di Lorenzo Patricia M.
Published: September 2012

The nucleus of the solitary tract (NTS) receives input from taste buds on the rostral tongue from the chorda tympani (CT) nerve. How this input is processed by the NTS was the subject of the present investigation. Here we used tetrodes to record from pairs or small groups of NTS cells as they responded to taste stimuli or electrical stimulation of the CT nerve in urethane-anesthetized rats. Once a pair (or small group) of NTS cells were isolated and identified as showing an evoked response to CT nerve stimulation, taste stimuli were presented in separate trials. Tastants consisted of 0.1 M NaCl, 0.01 M HCl, 0.01 M quinine HCl, and 0.5 M sucrose. Responses to various patterns of CT stimulation were then recorded. Functional connections among simultaneously recorded NTS cells were implied from analysis of cross-correlation functions of spike trains. We identified four groups of cells, not all of which responded to taste, with staggered latencies of response to CT nerve stimulation, ranging from ∼3 to 35 ms in ∼8- to 12-ms increments. Analyses of putative functional connectivity along with latencies of CT-evoked responses suggested that CT input arrives at the NTS in pulses or waves, each of which activates recurrent excitatory connections among NTS cells. These actions may amplify the incoming signal and refine its temporal pattern.
Choice ball: a response interface for two-choice psychometric discrimination in head-fixed mice
Authors: Sanders Joshua I. , Kepecs Adam
Published: September 2012

The mouse is an important model system for investigating the neural circuits mediating behavior. Because of advances in imaging and optogenetic methods, head-fixed mouse preparations provide an unparalleled opportunity to observe and control neural circuits. To investigate how neural circuits produce behavior, these methods need to be paired with equally well-controlled and monitored behavioral paradigms. Here, we introduce the choice ball, a response device that enables two-alternative forced-choice (2AFC) tasks in head-fixed mice based on the readout of lateral paw movements. We demonstrate the advantages of the choice ball by training mice in the random-click task, a two-choice auditory discrimination behavior. For each trial, mice listened to binaural streams of Poisson-distributed clicks and were required to roll the choice ball laterally toward the side with the greater click rate. In this assay, mice performed hundreds of trials per session with accuracy ranging from 95% for easy stimuli (large interaural click-rate contrast) to near chance level for low-contrast stimuli. We also show, using the record of individual paw strokes, that mice often reverse decisions they have already initiated and that decision reversals correlate with improved performance. The choice ball enables head-fixed 2AFC paradigms, facilitating the circuit-level analysis of sensory processing, decision making, and motor control in mice.
Lateralization in intrinsic functional connectivity of the temporoparietal junction with salience- and attention-related brain networks
Authors: Kucyi Aaron , Hodaie Mojgan , Davis Karen D.
Published: September 2012

Neuroimaging studies have demonstrated that the right temporoparietal junction (TPJ) is activated during detection of salient stimuli, including pain, in the sensory environment. Right TPJ damage more often produces spatial neglect than left TPJ damage. We recently reported a right lateralized system of white matter connectivity of the TPJ. However, lateralization in intrinsic TPJ functional connectivity during a task/stimuli-independent state has not been fully characterized. Here we used resting-state functional MRI in healthy humans to compare the functional connectivity of right and left TPJ with salience- and attention-related brain networks. Independent components analysis revealed that both right and left TPJ were functionally connected with a network that included the anterior insula, dorsolateral prefrontal cortex (PFC), and mid-cingulate cortex, considered to be the salience/ventral attention network. Dual regression revealed this network was more strongly connected with right TPJ than left TPJ. Seed-based functional connectivity analysis showed 1) negative connectivity the TPJ bilaterally with the “default mode network”; 2) positive connectivity of TPJ bilaterally with the salience/ventral attention network; 3) stronger connectivity between right TPJ compared with left TPJ with regions within the salience/ventral attention network and mid-insula, S2, and temporal/parietal opercula (implicated in pain); and 4) stronger connectivity of left TPJ compared with right TPJ with the “executive control network,” including the dorsomedial/medial PFC, inferior frontal gyrus, and cerebellum (crus I/II). Our findings build on classic lesion and neuroimaging studies, demonstrating a complex spatial network organization of lateralization in TPJ functional connectivity in the absence of an overt stimulus.
Working with memory: evidence for a role for the medial prefrontal cortex in performance monitoring during spatial delayed alternation
Authors: Horst Nicole K. , Laubach Mark
Published: September 2012

Neuronal spike activity was recorded in the medial prefrontal cortex (mPFC) as rats performed an operant spatial delayed alternation task. The sensitivities of neurons to choice, outcome, and temporal information-related aspects of the task were examined. About one-third of neurons were sensitive to the location of delayed responding while animals were at one of two spatially distinct response ports. However, many fewer neurons (<10%) maintained choice information over the delay, each exhibiting persistent differences in firing rates for only a portion of the delay. Another third of cells encoded information about behavioral outcomes, and some of these neurons (>20% of all cells) fired at distinct rates in advance of correct and incorrect responses (i.e., prospective encoding of outcome). Other cells were sensitive to reward-related feedback stimuli (>20%), the outcome of the preceding trial (retrospective encoding, 5–10%), and/or the time since a trial was last performed (10–20%). An anatomical analysis of the recording sites found that cells that were sensitive to choice, temporal, and outcome information were commingled within the middle layers of the mPFC. Together, our results suggest that spatial processing is only part of what drives mPFC neurons to become active during spatial working memory tasks. We propose that the primary role of mPFC in these tasks is to monitor behavioral performance by encoding information about recent trial outcomes to guide expectations and responses on the current trial. By encoding these variables, the mPFC is able to exert control over action and ensure that tasks are performed effectively and efficiently.
Is Evolution of Mating Preferences Inevitable? Random Mating in the Multisex System ofTetrahymena thermophila
Authors: Phadke Sujal S. , Cooper Lauren , Zufall Rebecca A.
Published: September 2012

Ciliate mating systems are highly diversified, providing unique opportunities to study sexual differentiation and its implications for mating dynamics. Many species of ciliates have multiple (>2) sexes. More sexes may mean more choice and an opportunity for evolution of preferential mating. We asked if the multiple sexes of the ciliateTetrahymena thermophilamate preferentially among each other. We quantified pairing frequencies among four sexes ofT. thermophilausing experiments that allowed the sexes to compete as mating partners. We found that all sexes mated equally frequently among each other, that is, we found no evidence of preferential mating with respect to sex. This suggests that the “mate choice” in this ciliate is binary, between whether to form a pair or not and, in this regard, sex facilitates only self-/non-self-distinction. Thus, presence of multiple sexes does not necessarily result in the evolution of mating bias, which could decrease the maximum amount of mating that would otherwise be possible in a population. Our result of random mating verifies a key assumption in the theoretical model of sex ratio evolution inT. thermophila. Investigation into molecular differences between the sexes will be necessary to reveal the mechanistic basis of random mating among them.
UvrD Participation in Nucleotide Excision Repair Is Required for the Recovery of DNA Synthesis following UV-Induced Damage inEscherichia coli
Authors: Newton Kelley N. , Courcelle Charmain T. , Courcelle Justin
Published: September 2012

UvrD is a DNA helicase that participates in nucleotide excision repair and several replication-associated processes, including methyl-directed mismatch repair and recombination. UvrD is capable of displacing oligonucleotides from synthetic forked DNA structuresin vitroand is essential for viability in the absence of Rep, a helicase associated with processing replication forks. These observations have led others to propose that UvrD may promote fork regression and facilitate resetting of the replication fork following arrest. However, the molecular activity of UvrD at replication forksin vivohas not been directly examined. In this study, we characterized the role UvrD has in processing and restoring replication forks following arrest by UV-induced DNA damage. We show that UvrD is required for DNA synthesis to recover. However, in the absence of UvrD, the displacement and partial degradation of the nascent DNA at the arrested fork occur normally. In addition, damage-induced replication intermediates persist and accumulate inuvrDmutants in a manner that is similar to that observed in other nucleotide excision repair mutants. These data indicate that, following arrest by DNA damage, UvrD is not required to catalyze fork regressionin vivoand suggest that the failure ofuvrDmutants to restore DNA synthesis following UV-induced arrest relates to its role in nucleotide excision repair.