bluuebunny/crossref_metadata_2025 huggingface dataset:
VANET Modelling and Statistical Properties of Connectivity in Urban Environment
Authors: Thuan Duong Hien , Cuu Ho Van , Do Hung Ngoc
Published: May 2016

This paper proposes a new approach for modelling Vehicular Ad Hoc Networks (VANETs) based on stochastic geometry and point processes, where road systems are modelled as random lines process and vehicle’s locations on a road are linear Poisson point processes. We derive some functions, which show the connectivity properties of VANETs under the impact of fading and path loss, that can be used for large vehicular networks analysis.
Jamming Impact on the Performance of MIMO Space Time Block Coding Systems over Multi-path Fading Channel
Authors: Shaheen Ehab M. , Samir Mohamed
Published: May 2016

The combined effect of broad/partial band jamming on the analysis performance of multi-input/multi-output (MIMO) space time block coding (STBC) systems over Rayleigh fading channel is often neglected in the literature. To this end, this paper investigates the impact of different kinds of jamming on the performance of MIMO STBC systems. Closed form expressions for the bit error probability (BEP) of the performance of binary phase shift keying (BPSK) STBC communication system over Rayleigh fading channel under the impact of both partial band and broad-band jamming for different number of transmitting and receiving antennas are presented. Computer simulations are provided to validate the theoretical developments. It has been found that the performance of such systems is severely deteriorated in the presence of strong jamming power (with a signal to jamming power ratio less than − 10dB) and the worst scenario occurs in the presence of broad-band jamming.
NetFPGA Based OpenFlow Switch Extension for Energy Saving in Data Centers
Authors: Vu Tran Hoang , Thanh Tran , Trong Vu Quang , Nam Pham Ngoc , Thanh Nguyen Huu
Published: May 2016

The increasing demand for data centers in both scale and size has led to huge energy consumption. The cost and environmental impact of data centers increases due to large amounts of carbon emissions. One solution to this problem is to intelligently control the power consumption of switches used in data centers. This paper proposes an extension to OpenFlow switches to support different power saving modes. The extension includes defining new messages in the OpenFlow protocol stack and designing an OpenFlow Switch Controller (OSC) that is able to turn on/off switches and disable/enable ports. To prove the soundness of the proposed extension, the functions of an OSC has been integrated in a NetFPGA based OpenFlow switch used in the ECODANE framework. The results presented in this paper can also be used by the OpenFlow compliant switches manufacturer or by power aware research community.
On the Double Doppler Effect Generated by Scatterer Motion
Authors: Pham Viet-Ha , Taieb Mohamed Haj , Chouinard Jean-Yves , Roy Sébastien , Huynh Huu-Tue
Published: May 2016

In a time-varying transmission channel, the received signals are subject to frequency shifts due to the Doppler effect. The Doppler frequency is dependent on the carrier frequency and channel variation rate. In a fixed wireless channel, the channel variations are caused by scatterer motion. In this paper, we investigate analytically the Doppler effects generated by scatterer motion under different scatterer velocity distributions using the ring-of-scatterers geometric model. The proposed model considers Doppler frequency components caused by scatterer mobility to both received and reflected signals at each scatterer, and therefore is called the double Doppler model. The analytical curves are compared and statistically tested with several measurement results published in the literature. At low scatterer speeds, e.g., generated by moving foliage, the exponential velocity distribution is an appropriate model to describe the time-varying nature of the fixed wireless channels. The curve fitting results also show that our analytical model better approaches the empirical curves than the single Doppler model does. However, further investigation is still needed to find a suitable scatterer velocity distribution that closely describes the double Doppler effect in fast-variation fixed wireless channels, e.g., caused by passing vehicles.
Chaotic Compressed Sensing and Its Application to Magnetic Resonance Imaging
Authors: Linh-Trung Nguyen , Minh-Chinh Truong , Tran-Duc Tan , Le Ha Vu , Do Minh Ngoc
Published: May 2016

Fast image acquisition in magnetic resonance imaging (MRI) is important, due to the need to find ways that help relieve patient’s stress during MRI scans. Methods for fast MRI have been proposed, most notably among them are pMRI (parallel MRI), SWIFT (SWeep Imaging with Fourier Transformation), and compressed sensing (CS) based MRI. Although it promises to significantly reduce acquisition time, applying CS to MRI leads to difficulties with hardware design because of the randomness nature of the measurement matrix used by the conventional CS methods. In this paper, we propose a novel method that combines the above-mentioned three approaches for fast MRI by designing a compound measurement matrix from a series of single measurement matrices corresponding to pMRI, SWIFT, and CS. In our method, the CS measurement matrix is designed to be deterministic via chaotic systems. This chaotic compressed sensing (CCS) measurement matrix, while retaining most features of the random CS matrix, is simpler to realize in hardware. Several compound measurement matrices have been constructed and examined in this work, including CCS-MRI, CCS-pMRI, CCS-SWIFT, and CCS-pSWIFT. Simulation results showed that the proposed method allows an increase in the speed of the MRI acquisition process while not compromising the quality of the acquired MR images.
An Improved White Space Prediction Algorithm for Cognitive Radio Systems
Authors: Phong Nguyen Huu , Bao Vo Nguyen Quoc , Huynh Huu-Tue
Published: May 2016

Cognitive radio (CR) is a promising technology to enhance the current low usage of limited frequency resources. TV white space (TVWS) - TV bands at a particular time in a particular geographic area that are not being used by licensed services - is perceived as the most suitable frequency bands for CR. This paper proposes a new prediction TVWS algorithm for CR systems based on the ITU 1546.1 and the Okumura-Hata models. The proposed algorithm is verified with the data of 22 provinces in the South of Vietnam. The numerical results confirm the advantage of the proposed algorithm as well as the possibility of TVWS CR networks.
Group Scheduling for MultiChannel in OBS Networks
Authors: Quoc Nguyen Hong , Nhat Vo Viet Minh , Son Nguyen Hoang
Published: May 2016

Group scheduling is a scheduling operation of optical burst switching networks in which the burst header packets arriving in each timeslot will schedule their following bursts simultaneously. There have been many proposals for group scheduling (such as OBS-GS, MWIS-OS and LGS), but they consider mainly to schedule the arriving bursts which have the same wavelength on an output data channel. Another suggestion is GreedyOPT which considers the group scheduling for multichannel with the support of full wavelength converters, but it is not optimal. This article proposes another approach of group scheduling which is more optimal and has a linear complexity.
An Adaptive Bandwidth Notch Filter for GNSS Narrowband Interference Mitigation
Authors: Nguyen Tu Thi-Thanh , La The Vinh , Ta Tung Hai , Nguyen Hoang-Lan Thi , Motella Beatrice
Published: May 2016

The low level of received signals power makes Global Navigation Satellite Systems (GNSS) receivers vulnerable to many classes of disturbing signals. Among them, narrow band interference (NBI) might cause serious receiver performance degradation. Cancellation of NBI can be implemented by using notch filters (NF), which are controlled by two parameters: the notch frequency, which specifies the band center, and the notch bandwidth, which defines the spectrum area to be removed. The literature on the topic focuses on adapting the notch frequency, without estimating the filter bandwidth. This paper proposes a method able to determine both the notch parameters, optimizing the interference suppression. The performance analysis shows a good improvement by using the adaptive bandwidth notch filter.
Performance Analysis of Adaptive Modulation for Distributed Switch-and-Stay Combining with Single Relay
Authors: Bao Vo Nguyen Quoc , Thanh Tran Thien , Do-Hong Tuan
Published: May 2016

In this paper we present our investigation of the performance of a distributed switch-and-stay scheme and a solution for low-complexity cooperative relaying under adaptive transmission. We are able to derive the closed-form expressions of the occurrence probability, the outage probability, the bit error probability, and the achievable spectral efficiency of the proposed scheme for Rayleigh fading channels. Simulations are performed to verify the analytic results. It is shown that, by applying adaptive modulation, the achievable spectral efficiency of the system is improved significantly, and the proposed scheme achieves the same spectral efficiency as compared to that of the incremental relaying but with a lower relay activation time.
Development of Rural Entrepreneurship through SHGS: An Empirical Study
Authors: Khan Mohd. Arshad
Published: May 2016

Entrepreneurship has been gaining greater significance at international stage under changing economic scenario. Indian economy is on the threshold of accelerated economic growth driven by entrepreneurship. The present study is an attempt to find out impact of microfinance through SHGs in development of rural entrepreneurship. The study shows that though microfinance through SHGs have helped in promotion of rural entrepreneurship but there are various problems which the rural enterprises are currently facing like insufficient transportation and storage services, lack of quality control measures, non-availability of right type of raw material, difficulty in selection of products, poor linkage with selling bodies, small scale of production, lack of trained workers and improper communication with other developmental agencies and most importantly long and complicated procedures to avail financial help. All these factors are restricting the rural enterprises from reaching their full potential. Activity wise analysis of the respondents suggests that selected SHG members are mainly involved in activities which require lesser amount of forward and backward linkages. The activities requiring more linkages and service inputs have not been successful to that extent.
Advertising Appeals and Purchase Intentions: An Empirical Study
Authors: Kumar Alok , Pathak Pramod
Published: May 2016

The world of advertising appeals is fascinating. Although not much research has been done in our country on the subject, yet this finds place in almost all advertising endeavours in our country. One important aspect is to know whether such ad appeals do influence the purchase intention of a consumer. The paper covers a primary study, involving such an aspect where few statistical tools have been used to come to a certain conclusion
Effectiveness of Fund Management at Local Government Bodies in Nepal
Authors: Paudel Narayan Prasad
Published: May 2016

The study has examined the effectiveness of fund management at local government bodies in Nepal. Many problems could be observed at the local level government units, in terms of management of fund, lack of capacity, lack of elected representatives at grassroots level, political transition, lack of capacity to use information, and weak institutional mechanism. The study reports that the data on fund utilization should be easily available and comprehensible to the general public so that people can extract data, compare them, analyze them, and use them as per their needs. The study further highlights that the government need to focus on adequacy of the fund, proper mechanism of budget spent, and enhancing the efficiency of financial planning and budgetary process at the local level. To upgrade the credibility of the budget at the local and central government units, some measures need to be considered, for example efficiency of Municipality in delivery of service need to be strengthened, level of development work need to be visible enough.
Consumer Buying Perception and Preferences towards Organized Retailing: An Empirical Analysis of Shopping Malls in Lucknow
Authors: Pandey Krishan Kant , Bhatla Neeta
Published: May 2016

Retail industry in India, being one of the largest retail industries in the world in terms of growth, provides goods and services to a large number of people from various strata of society. Retail sector also supports to create huge employment opportunities for the young generation as new form of organized retail sector has emerged within the retail industry. The objective of this paper is to examine the activities in which consumers engage in malls and why the mall culture is gaining acceptance among consumers. The paper focuses on the factors (specially demographic and social) which influence the shopping at malls in Lucknow. Another objective of study is to understand consumer behavior towards shopping malls and also to find out the consumer’s satisfaction level from shopping malls. The study finds that consumers prefer shopping, eating at food courts, window shopping and entertainment in the form of movies at multiplexes or video game parlors in malls. Consumers prefer the air conditioned environment(shopping ambiance), availability of several product categories under one roof, quality of service, car parking facilities, convenience of shopping and the confidence that the store-owner is not cheating in context of mall. So, the retail industry in India must take concrete steps to withstand the growing global competition in market.
Finite element modeling and experimental verification of lightweight steel floor vibration
Authors: Park Je-Woo , Ha Tae-Hyu , Kim Hongjin
Published: May 2016

Due to the lack of design standard and the difficulty of analysis, the floor vibration analysis of lightweight steel floors has received less attention than the analysis of typical floor structures. In this paper, the finite element model for lightweight steel floors is presented utilizing the rigid link and realistic support restraints. The rigid rink is used to solve the problem of difference in the centroid of beam, joist, and flooring material and to guarantee the same behavior of those members. Two different support restraints, all fixed restraint and mixture of fixed and released restraint, are used in the analysis. The finite element model is verified through the human impact loading test of the full-scale light-weight steel floors that have different joist condition and middle beam. The finite element analysis results indicate that the different joists having same moment of inertia yield similar natural frequencies, while the test results of full-scale floors show that the floor with the closed shaped joists yields higher natural frequency than the floor with open shaped joists. The test results also indicate that the finite element analysis using the mixture of fixed and released support restraint yields closer natural frequencies to those of actual floors.
Seismic behavior characteristic of high damping rubber bearing through shaking table test
Authors: Oh Ju , Jang Changhwan , Kim Jin Ho
Published: May 2016

We investigated a high damping rubber bearing (HDRB) that mitigates damage to buildings and bridges from earthquakes. An HDRB can bear large loads for long periods of time and is capable of large deformations during an earthquake. The characteristics of the HDRB considered in this research include a very high damping capacity, with an equivalent damping factor of more than 15 % for a large earthquake. Moreover, we examined various dependency properties such as compressive stress, frequency, and repeated loading. To evaluate seismic isolation with an HDRB on several earthquake waves, we performed a shaking table test. In this test, deck acceleration was measured by accelerometers. Shear forces on piers were surveyed by using load cells. Furthermore, the seismic capacity of an isolated system with an HDRB was compared with a non-isolated system through shaking table tests. The results show that deck acceleration and shear force were relatively reduced by the HDRB.
Research on aerodynamic noise of the high-speed transportation based on experiment and simulation
Authors: Tang Zhi , Liu Zhi-hui , Wang Qian , Li Zhen
Published: May 2016

By means of the switch inside the numerical model, the small-scale pulsation on the near wall is simulated by URANS method. Areas away from the wall are adjusted to the sub grid scale (SGS) models automatically, which is simulated for the vortex movement by LES method. Via the automatically adjustable method in accordance with local grids, not only the advantage concerning the small computation amount of URANS method can be shown in the boundary layer, but also the large-scale vortex movement can be simulated in the areas away from the wall. Firstly, based on the mentioned method, aerodynamic characteristics of the high-speed transportation in the near field are calculated numerically. As shown from the corresponding result, due to the sudden structural changes of nose tip and bogies, their surface pressures are larger. Therefore, the numerical optimization of the aerodynamic characteristics for the high-speed transportation can be conducted from this aspect. Secondly, based on the results of aerodynamic characteristics, the near-field and far-field aerodynamic noises of the high-speed transportation are also calculated. The near-field radiation noise is larger near the noise tip and bogies, while the far-field noise is greater near the ground. Finally, the calculation results of the near-field and far-field for the high-speed transportation are verified by experiments, and they are consistent with each other. As a result, the numerical model established in the paper is reliable.
Bifurcation and chaos for electromechanical coupling torsional vibration in rolling mill system driven by DC motor
Authors: Liu Haoran , Liu Jinjie , Liu Fei , Zhu Zhanlong , Wang Kun , Liu Shuang
Published: May 2016

Bifurcation and chaos for electromechanical coupling torsional vibration in rolling mill system driven by DC motor is studied in this paper. Considering the electromechanical devices under unsaturated magnetic circuit, the dynamical equation of electromechanical coupling vibration in rolling mill drive system is deduced by using the dissipation Lagrange equation. The equivalent low-dimensional bifurcation equation, which can reveal the influence of system parameters on the nonlinear dynamic characteristics, is obtained by reducing the dimensionality system using the method of Lyapunov-Schmidt reduction, and the static bifurcation characteristic is analyzed by using the singularity theory. The torsional rigidity of rotating shaft and harmonic excitation are chosen as the bifurcation parameters. Finally, the simulation is carried out with actual parameters, the bifurcation diagram, Poincare map and the maximum Lyapunov exponent are also given, which show the influence of bifurcation parameters on the chaotic motions of the system.
Aerodynamic characteristics of multiple flapping wing configurations
Authors: Shen Yuan , Cai Hongming
Published: May 2016

Natural flyers and man-made MAVs generally use multiple flapping wing configurations. To understand the aerodynamic performance, three different flapping configurations: single wing, tandem wings, and biplane wings are numerically simulated by a URANS solver coupled with an overset grid method. Moreover, effect of kinematics including oscillating frequency, angle of attack and wing to tail distance are detailed investigated. Results show that the wing-tail interaction significantly benefits the thrust generation when the wings are tandem arranged. Additionally, the tandem arrangement is the most efficiency configuration when applied with high frequencies. Biplane wings model has the most inefficiency propulsive performance, nevertheless it can provide an extensive aerodynamic force. With the increasing AOA, biplane has the largest critical angle from thrust to drag. Wing-tail interaction becomes weaker when the tail is mounted further from the flapping wings. The present of the tail in tandem model bring more benefits compared with the tail in biplane model. The tail in biplane model is only functional for flight control when applied with a non-zero angle of attack.
Effect of sink flow on dual-valve electro-hydraulic excitation system
Authors: Meng Zhen , Wu Chuan-yu , Ni Jing
Published: May 2016

In this study, the main goal is to investigate the displacement gain characteristics of novel dual-valve Electro-Hydraulic Excitation system (EHES). Relative to conventional system, the dual-valve system can improve the amplitude range, but the range is always affected by some nonlinear factors. In order to analysis on the issue, a nonlinear mathematical model of dual-valve EHES is established based on Bernoulli and classical electro-hydraulic servo equation. Then, the results of numerical simulations by using of the MATLAB/Simulink software are compared with experimental results. Simulation and experimental results show that the sink flow mainly influences on the flow dynamic characteristics of dual-valve EHES. Because of that, dual-valve EHES only can improve 50 %-70 % of displacement within 5 to 50 Hz of excitation frequency and 45 %-80 % of displacement amplitude within 20 % to 100 % of command value.
Free vibration of thick annular sector plate on Pasternak foundation with general boundary conditions
Authors: Liu Huimin , Liu Fanming , Bai Haoran , Yang Ranbing
Published: May 2016

In this paper, the free vibration of the thick annular sector plate on Pasternak foundation with general boundary conditions is presented by using the three-dimensional elasticity theory and the improved Fourier series method. The displacements of the thick annular sector plate are expanded to be the three-dimensional (3-D) Fourier cosine series supplemented with several auxiliary functions to eliminate all the relevant discontinuities of the displacements and their derivatives at the edges with general boundary conditions. This method can be universally applied to any kinds of classical boundaries, elastic boundaries and the combinations of both boundaries without any special change in the solution procedure. The excellent accuracy and reliability of the current solutions are demonstrated by numerical examples and comparison of the present results with those available in the literature. Furthermore, numerous new results for thick annular sector plates on Pasternak foundation with general elastic restrains are presented. In addition, comprehensive studies on the effects of the elastic restraint parameters, geometric parameters and elastic foundation coefficients are also reported.
A two-step method composed of wavelet transform and model updating method for multiple damage diagnosis in beams
Authors: Abbasnia Reza , Mirzaei Borhan , Yousefbeik Seyedmohamadmahdi
Published: May 2016

In the present study, a two-step approach comprised of wavelet transform and model updating method for multiple structural damage localization and quantification in beams is proposed. The first step is commenced with applying wavelet transform to axial components of mode shapes so as to predict where the damages are located. During this step, wavelet transform might mistakenly detect a number of elements as impaired due to both sampling interval and middle support effect. In the next step, by defining a damage sensitive objective function consisting of natural frequencies and mode shapes, damage intensities at predicted locations will be computed via model updating method employing ECBO (Enhanced Colliding Bodies Optimization) algorithm. The problem with mistakenly predicted damaged locations will be addressed by reported damage intensities during the second step. The present study also indicates that this two-step method greatly assists in reducing the number of variables during model updating process leading to more precise results. Three numerical examples with multiple damages and noisy modal data are studied in order to guarantee the efficacy of the method. Moreover, one numerical example is solved with a number of other Meta-Heuristic algorithms including GA (Genetic Algorithm), CSS (Charged System Search), Pattern Search and Cuckoo algorithm whose results are compared to ECBO algorithm with the intention of ensuring the veracity of ECBO results. The results vividly demonstrate that this method is highly efficient even in the presence of noise.
The effect of various design codes and dynamic magnification on buildings with torsional irregularity
Authors: Lee Kwang-Ho , Jeong Seong-Hoon , Han Seongwoo , Kim Kang Su
Published: May 2016

Seismic provisions have utilized design eccentricities to reduce planar irregularities in lateral stiffness of buildings. In calculating a design eccentricity, the torsional amplification factor may be applied either to accidental eccentricity or to both inherent and accidental eccentricities according to design codes. In this paper, different code provisions and their impact on torsional responses of buildings are investigated using example buildings with various aspect ratios and inherent eccentricities. It was found that the design eccentricity in KBC-2009 using torsional amplification factor for only accidental eccentricity reflects the dynamic magnification more accurately than that in KBC-2006 using this factor for both inherent and accidental eccentricity. And dynamic magnification of a torsionally imbalanced building is affected by the size of seismic design force of response spectrum analysis than design eccentricity of equivalent static analysis in KBC-2009. In other words, design eccentricity including torsional amplification factor in KBC-2009 do not reflect the dynamic magnification accurately.
Dynamic characteristics of rotor system and rub-impact fault feature research based on casing acceleration
Authors: Wang N. F. , Jiang D. X. , Han T.
Published: May 2016

Aimed at the vibration of whole aero-engine, a coupled dynamic model of rotor-ball bearing-stator of aero-engine is built. By means of the lumped mass method, taking into account the nonlinear rub-impact, bearing failure force and deformation of the casing, the dynamic equation of the system containing typical rub-impact is derived. The response of the system under different conditions is obtained by using the fourth order Runge-Kutta numerical integration algorithm. By adopting the finite element analysis software ANSYS, the finite element model of the rotor shaft is established and the first six-order natural frequencies of the rotor system are acquired. Taking advantage of the parameters of the signal in time domain and frequency domain, frequency characteristics are extracted as the fault features. The single-point rubbing experiment is carried out in the test rig, and the working speed is higher than the first critical speed, so the rotor shaft is flexible rotor. By the methods of spectrum and cepstrum analysis, the rub-impact characteristics of the casing vibration acceleration time series data are analyzed. The results show that the casing vibration acceleration has obvious impact characteristics; the impact frequency is equal to the product of rotating frequency and number of the blades; the impact frequency component and its multiple-frequencies are demonstrated in the frequency spectrum; the strength of impact is modulated by the rotating frequency, so that there are families of side bands on impact frequency and both sides of frequency doubling, and the interval of sideband equals the rotating frequency. The frequency components of the rotating frequency and its frequency doubling are clearly shown in the cepstrum. By comparing the simulation and experiment, the rubbing characteristics found out in this paper has enough accuracy.
Investigation of effect of acoustic field to coagulation of particles in air flow
Authors: Čereška A. , Tetsman I. , Maskeliūnas R. , Grinbergienė I. , Paškevičius P.
Published: May 2016

In the paper theoretical and experimental investigations of the effect of acoustic field to coagulation of particles in air flow are presented. For the conduction of experimental investigations, a special experimental setup with measurement devices was designed and used. Principle of operation of the proposed experimental setup is presented and the method of conduction of experimental investigations is described. Investigations of effectiveness of coagulation of rigid particles of very small diameter have been performed and dependencies from the sound pressure of the acoustic field and its frequency were investigated. For excitation of the acoustic field two sound generators were used: piezoelectric and aeroacoustic. As a result of the performed investigations it was determined that with the increase of the frequency of acoustic excitation velocity of coagulation of particles increases when the diameter of the particles does not exceed 1 μm. For the most effective coagulation of the particles having the diameter up to 1 μm ultrasonic frequency is required. For the particles with the diameter larger than 1 μm frequency lower than ultrasonic is required. Dependencies of velocity of coagulation of particles from the frequency of acoustic signal and from its amplitude were determined. Initial granulometric constituent parts were compared with the constituent parts obtained after the experimental investigations.
Signal intensity dynamics of malignant lymphoma in diffusion-weighted magnetic resonance imaging compared to positron emission tomography
Authors: Bliūdžius Rytis , Dobrovolskienė Laima , Basevičius Algidas , Veikutis Vincentas , Juškevičius Matas , Oberauskas Vaidas
Published: May 2016

This article discusses a study performed with an aim to determine the usefulness of diffusion-weighted MRI in pre-treatment assessment and evaluation of chemotherapy response of mediastinal lesions of malignant lymphoma by analysing signal intensity, accumulation of contrast agent and changes in values of ADC. Comparing the results of PET/CT and DW-MRI was another goal of this study. We reviewed data of 21 patients that underwent treatment during years 2013-2014 at the Hospital of Lithuanian University of Health Sciences Kaunas Clinics and had DW-MRI and PET/CT scans carried out. For all patients the diagnosis of malignant lymphoma in mediastinal lymph nodes was confirmed histological. Whether the lymphoma was in active state was determined by PET/CT or histological data. In MRI scans, signal intensity and ADC values were evaluated, while in PET/CT maximum and average standardized uptake values were assessed. Patients underwent chemotherapy and follow up scans were performed to evaluate response. In total, 25 PET/CT and 50 DW-MRI scans were analysed. We found statistically significant difference of values of ADC in active and inactive states of malignant lymphoma of mediastinal lymph nodes. In follow up tests, performed during 2 years after treatment, a tendency of decreasing ADC values over time was seen when chemotherapy was successful and no relapse was observed. Among the reviewed cases, DW-MRI had slightly worse specificity than PET/CT in differentiation of malignant and benign changes in lymph nodes.
Water and modernization styles: measuring territorial knowledge based on water management policies in Santiago de Querétaro (Mexico)
Authors: Mesa Aníbal , Luna-Soria Hugo , Castilla José Luis
Published: May 2016

This paper explores the relation that the inhabitants of an urban space, in this case the city of Querétaro, Mexico, establish with the water supply system. In particular, it seeks to understand the way in which the supply-side policies are configuring the relation that subjects keep with the territory around them. For this purpose, four variables (educational level, land value, housing legal status and development goals) are crossed with the existing knowledge about the water supply system, paying special attention to the differences among different city areas. The final goal is to understand how water modernization policies are affecting the links between subjects and territories. The results express that in the areas where those policies are more deeply consolidated, the links with territory are weaker, generating weakness in the ability to articulate management alternatives. Another weakness lies in the ability to create a much more active role of the subjects in their relation with water and its management as a basic resource.
A critical review of groundwater utilization and management in China's inland water shortage areas
Authors: Dou Xiangsheng
Published: May 2016

Groundwater, as an important store of freshwater, plays a more critical role in sustaining the ecosystem and enhancing human adaptation to changing climate than surface water. In particular, it can store large volumes of water to naturally buffer the pressure of water shortage against seasonal changes in rainfall. However, groundwater itself is also vulnerable to climate change, showing a great change in hydrologic cycle. Therefore, effective groundwater management has a strategic importance for China's water security. At present, China is facing a groundwater crisis because of the dual effects of natural and anthropogenic factors. Many new ideas and solutions have been given in previous studies on groundwater utilization and management. This paper vividly captures these studies. The paper summarizes groundwater properties and the situation of groundwater development and utilization. The paper also reports challenges, strategies and policies in groundwater sustainability.
Rapid Lateral Extraction of Otoliths that Maintains the Integrity of Fish Product to Improve Access to Catches and Reduce Potential Sampling Biases
Authors: Wakefield Corey B. , Boddington Dion K. , Newman Stephen J.
Published: May 2016

The capacity to sample otoliths of fish from commercial, recreational, artisanal or subsistence catches can be constrained if the dissection process results in alterations to their external appearance and thus reduces its value and/or shelf life. There can also be significant biases incorporated into the collection of otolith samples if access is only granted relative to the size of the fish (i.e. if smaller fish are sold whole). To reduce such limitations, we herein describe a rapid and simple method of lateral otolith extraction that maintains the integrity of the fish product, and thus reduces potential biases in sample collection for age structure data. Representative sampling is an important consideration for the collection of age structure data when it is intended to be used in fisheries stock assessments.
Research Data Sharing and Reuse Practices of Academic Faculty Researchers: A Study of the Virginia Tech Data Landscape
Authors: Shen Yi
Published: May 2016

This paper presents the results of a research data assessment and landscape study in the institutional context of Virginia Tech to determine the data sharing and reuse practices of academic faculty researchers. Through mapping the level of user engagement in â€œopenness of data,â€ â€œopenness of methodologies and workflows,â€ and â€œreuse of existing data,â€ this study contributes to the current knowledge in data sharing and open access, and supports the strategic development of institutional data stewardship. Asking faculty researchers to self-reflect sharing and reuse from both data producersâ€™ and data usersâ€™ perspectives, the study reveals a significant gap between the rather limited sharing activities and the highly perceived reuse or repurpose values regarding data, indicating that potential values of data for future research are lost right after the original work is done. The localized and sporadic data management and documentation practices of researchers also contribute to the obstacles they themselves often encounter when reusing existing data.Â
AMPK Activation by Metformin Suppresses Abnormal Extracellular Matrix Remodeling in Adipose Tissue and Ameliorates Insulin Resistance in Obesity
Authors: Luo Ting , Nocon Allison , Fry Jessica , Sherban Alex , Rui Xianliang , Jiang Bingbing , Xu X. Julia , Han Jingyan , Yan Yun , Yang Qin , Li Qifu , Zang Mengwei
Published: May 2016

Fibrosis is emerging as a hallmark of metabolically dysregulated white adipose tissue (WAT) in obesity. Although adipose tissue fibrosis impairs adipocyte plasticity, little is known about how aberrant extracellular matrix (ECM) remodeling of WAT is initiated during the development of obesity. Here we show that treatment with the antidiabetic drug metformin inhibits excessive ECM deposition in WAT of ob/ob mice and mice with diet-induced obesity, as evidenced by decreased collagen deposition surrounding adipocytes and expression of fibrotic genes including the collagen cross-linking regulator LOX. Inhibition of interstitial fibrosis by metformin is likely attributable to the activation of AMPK and the suppression of transforming growth factor-β1 (TGF-β1)/Smad3 signaling, leading to enhanced systemic insulin sensitivity. The ability of metformin to repress TGF-β1-induced fibrogenesis is abolished by the dominant negative AMPK in primary cells from the stromal vascular fraction. TGF-β1-induced insulin resistance is suppressed by AMPK agonists and the constitutively active AMPK in 3T3L1 adipocytes. In omental fat depots of obese humans, interstitial fibrosis is also associated with AMPK inactivation, TGF-β1/Smad3 induction, aberrant ECM production, myofibroblast activation, and adipocyte apoptosis. Collectively, integrated AMPK activation and TGF-β1/Smad3 inhibition may provide a potential therapeutic approach to maintain ECM flexibility and combat chronically uncontrolled adipose tissue expansion in obesity.
Cerebrovascular Safety of Sulfonylureas: The Role of KATP Channels in Neuroprotection and the Risk of Stroke in Patients With Type 2 Diabetes
Authors: Liu Rui , Wang Haitao , Xu Baofeng , Chen Wenliang , Turlova Ekaterina , Dong Nan , Sun Christopher L.F. , Lu Yangqingqin , Fu Hanhui , Shi Ranran , Barszczyk Andrew , Yang Dongzi , Jin Tianru , Mannucci Edoardo , Feng Zhong-Ping , Sun Hong-Shuo
Published: May 2016

Sulfonylureas are ATP-sensitive potassium (KATP) channel blockers commonly used in the treatment of type 2 diabetes mellitus (T2DM). Activation of KATP channels plays a neuroprotective role in ischemia; thus, whether sulfonylureas affect the outcomes of stroke in patients with T2DM needs to be further studied. In our study, streptozotocin (STZ)-induced diabetic mice subjected to transient middle cerebral artery occlusion (MCAO) showed larger areas of brain damage and poorer behavioral outcomes. Blocking the KATP channel by tolbutamide increased neuronal injury induced by oxygen-glucose deprivation (OGD) in vitro and permanent MCAO (pMCAO) in vivo. Activating the KATP channel by diazoxide reduced the effects of both the OGD and pMCAO. Western blot analysis in STZ mouse brains indicated an early increase in protein levels of N-methyl-d-aspartate receptor 2B and postsynaptic density protein-95, followed by a decrease in phosphorylation of glycogen synthase kinase 3β. Our systematic meta-analysis indicated that patients with T2DM treated with sulfonylureas had a higher odds ratio for stroke morbidity than those who received comparator drugs. Taken together, these results suggest that sulfonylurea treatment in patients with T2DM may inhibit the neuroprotective effects of KATP channels and increase the risk of stroke.
Differential Roles of Insulin and IGF-1 Receptors in Adipose Tissue Development and Function
Authors: Boucher Jeremie , Softic Samir , El Ouaamari Abdelfattah , Krumpoch Megan T. , Kleinridders Andre , Kulkarni Rohit N. , O’Neill Brian T. , Kahn C. Ronald
Published: May 2016

To determine the roles of insulin and insulin-like growth factor 1 (IGF-1) action in adipose tissue, we created mice lacking the insulin receptor (IR), IGF-1 receptor (IGF1R), or both using Cre-recombinase driven by the adiponectin promoter. Mice lacking IGF1R only (F-IGFRKO) had a ∼25% reduction in white adipose tissue (WAT) and brown adipose tissue (BAT), whereas mice lacking both IR and IGF1R (F-IR/IGFRKO) showed an almost complete absence of WAT and BAT. Interestingly, mice lacking only the IR (F-IRKO) had a 95% reduction in WAT, but a paradoxical 50% increase in BAT with accumulation of large unilocular lipid droplets. Both F-IRKO and F-IR/IGFRKO mice were unable to maintain body temperature in the cold and developed severe diabetes, ectopic lipid accumulation in liver and muscle, and pancreatic islet hyperplasia. Leptin treatment normalized blood glucose levels in both groups. Glucose levels also improved spontaneously by 1 year of age, despite sustained lipodystrophy and insulin resistance. Thus, loss of IR is sufficient to disrupt white fat formation, but not brown fat formation and/or maintenance, although it is required for normal BAT function and temperature homeostasis. IGF1R has only a modest contribution to both WAT and BAT formation and function.
Human Type 1 Diabetes Is Characterized by an Early, Marked, Sustained, and Islet-Selective Loss of Sympathetic Nerves
Authors: Mundinger Thomas O. , Mei Qi , Foulis Alan K. , Fligner Corinne L. , Hull Rebecca L. , Taborsky Gerald J.
Published: May 2016

In humans, the glucagon response to moderate-to-marked insulin-induced hypoglycemia (IIH) is largely mediated by the autonomic nervous system. Because this glucagon response is impaired early in type 1 diabetes, we sought to determine if these patients, like animal models of autoimmune diabetes, have an early and severe loss of islet sympathetic nerves. We also tested whether this nerve loss is a permanent feature of type 1 diabetes, is islet-selective, and is not seen in type 2 diabetes. To do so, we quantified pancreatic islet and exocrine sympathetic nerve fiber area from autopsy samples of patients with type 1 or 2 diabetes and control subjects without diabetes. Our central finding is that patients with either very recent onset (<2 weeks) or long duration (>10 years) of type 1 diabetes have a severe loss of islet sympathetic nerves (Δ = −88% and Δ = −79%, respectively). In contrast, patients with type 2 diabetes lose no islet sympathetic nerves. There is no loss of exocrine sympathetic nerves in either type 1 or type 2 diabetes. We conclude that patients with type 1, but not type 2, diabetes have an early, marked, sustained, and islet-selective loss of sympathetic nerves, one that may impair their glucagon response to IIH.
Heterogeneous Contribution of Insulin Sensitivity and Secretion Defects to Gestational Diabetes Mellitus
Authors: Powe Camille E. , Allard Catherine , Battista Marie-Claude , Doyon Myriam , Bouchard Luigi , Ecker Jeffrey L. , Perron Patrice , Florez Jose C. , Thadhani Ravi , Hivert Marie-France
Published: May 2016

OBJECTIVE

To characterize physiologic subtypes of gestational diabetes mellitus (GDM).

RESEARCH DESIGN AND METHODS

Insulin sensitivity and secretion were estimated in 809 women at 24–30 weeks' gestation, using oral glucose tolerance test–based indices. In women with GDM (8.3%), defects in insulin sensitivity or secretion were defined below the 25th percentile in women with normal glucose tolerance (NGT). GDM subtypes were defined based on the defect(s) present.

RESULTS

Relative to women with NGT, women with predominant insulin sensitivity defects (51% of GDM) had higher BMI and fasting glucose, larger infants (birth weight z score 0.57 [−0.01 to 1.37] vs. 0.03 [−0.53 to 0.52], P = 0.001), and greater risk of GDM-associated adverse outcomes (57.6 vs. 28.2%, P = 0.003); differences were independent of BMI. Women with predominant insulin secretion defects (30% of GDM) had BMI, fasting glucose, infant birth weights, and risk of adverse outcomes similar to those in women with NGT.

CONCLUSIONS

Heterogeneity of physiologic processes underlying hyperglycemia exists among women with GDM. GDM with impaired insulin sensitivity confers a greater risk of adverse outcomes.
Cognitive Dysfunction: Part and Parcel of the Diabetic Foot
Authors: Natovich Rachel , Kushnir Talma , Harman-Boehm Ilana , Margalit Daniella , Siev-Ner Itzhak , Tsalichin Daniel , Volkov Ilia , Giveon Shmuel , Rubin-Asher Deborah , Cukierman-Yaffe Tali
Published: May 2016

OBJECTIVE

The presence of a foot ulcer increases the self-treatment burden imposed on the individual with diabetes. Additionally, this condition increases the cognitive demands needed for adherence to medical recommendations. A potential gap could exist between medical recommendations and the individual’s ability to implement them. Hence, the goal of this study was to examine whether the cognitive profile of people with diabetic foot ulcers differs from that of people with diabetes without this complication.

RESEARCH DESIGN AND METHODS

This was a case-control study. Ninety-nine individuals with diabetic foot ulcers (case patients) and 95 individuals with type 2 diabetes (control subjects) (age range 45–75 years), who were matched for diabetes duration and sex, underwent extensive neuropsychological evaluation using a NeuroTrax computerized battery, digit symbol, and verbal fluency tests. A global cognitive score after standardization for age and education was computed as well as scores in the following six cognitive domains: memory, executive function, reaction time, attention, psychomotor abilities, and estimated premorbid cognition.

RESULTS

Individuals with diabetic foot ulcers had significantly (P < 0.001) lower cognitive scores than individuals with diabetes without this complication, in all tested cognitive domains, excluding estimated premorbid cognition. Individuals with diabetic foot ulcers demonstrated a significant difference between precognitive and current cognitive abilities, as opposed to the nonsignificant difference among control subjects. The differences persisted in multivariable analysis after adjusting for depression and smoking.

CONCLUSIONS

Individuals with diabetic foot ulcers were found to possess fewer cognitive resources than individuals with diabetes without this complication. Thus, they appear to face more self-treatment challenges, while possessing significantly fewer cognitive resources.
Carbohydrate Content in the GDM Diet: Two Views: View 2: Low-Carbohydrate Diets Should Remain the Initial Therapy for Gestational Diabetes
Authors: Mulla Wadia R.
Published: May 2016

IN BRIEF The appropriate dietary intervention for gestational diabetes mellitus (GDM) is not clear. Traditionally, a low-carbohydrate diet has been prescribed. Recently, there has been a movement to prescribe a diet higher in nutrient-dense carbohydrate as the initial treatment for GDM. At this time, there is insufficient outcome data to support this type of diet.
Oral Medications for Diabetes in Pregnancy: Use in a Rural Population
Authors: Thorkelson Shelley Jayne , Anderson Kristi R.
Published: May 2016

IN BRIEF The oral agents glyburide and metformin are both recommended by many professional societies for the treatment of gestational diabetes mellitus (GDM). Both therapeutic modalities have published safety and efficacy data, but there remains much debate among experts. Providers need a clear treatment plan for GDM based on a predictable level of clinical success in obtaining treatment goals. The proper selection of ideal candidates is paramount in achieving clinical success with the use of these medications in the treatment of GDM. This article presents clinical strategies for using oral agents in the management of GDM based on a pragmatic approach taken in a group of rural Native American women.
Pediatric Surgical Oncology in Bangladesh: Incidence and Prevalence (Global & Bangladesh)
Authors: Hasina Kaniz
Published: May 2016

Abstract not availableJ. Paediatr. Surg. Bangladesh 5(2): 37-39, 2014 (July)