bluuebunny/crossref_metadata_2025 huggingface dataset:
Generic, Anthracene‐Based Hydrogel Crosslinkers for Photo‐controllable Drug Delivery
Authors: Wells Laura A. , Brook Michael A. , Sheardown Heather
Published: May 2011

Light‐responsive polymers with controllable, reversible crosslink mechanisms have the potential to create unique biomaterials with stimulus‐controlled swelling, degradation and diffusion properties useful in tissue engineering and drug delivery applications. Generic photodimerizing polyethylene glycol–anthracene macromolecules that may be grafted to various polymers to effectively control their crosslinking via a photodimerization mechanism have been developed. These generic crosslinkers were shown to effectively introduce photoresponsive properties into hyaluronate and alginate as model hydrophilic polymers. In vitro testing using human corneal epithelial cells was used to demonstrate cytocompatibility of the resulting photogels. The effective crosslinking density of the photogels could be increased resulting in a decrease in the release rate of small and large molecules from the photogels following exposure to 365 nm light. This tuneable crosslinking has the potential to manipulate the delivery rates of therapeutics resulting in control over treatment profiles and may lend itself to various applications, which may benefit from light induced changes in crosslinking.

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Local specific absorption rate control for parallel transmission by virtual observation points
Authors: Eichfelder Gabriele , Gebhardt Matthias
Published: May 2011

The supervision of local specific absorption rate (SAR) in parallel transmission applications in MRI is crucial. One existing approach is to use electromagnetic simulations including human anatomical models and to precalculate the electric field distributions of each individual channel. These can be superposed later with respect to certain combined excitations under investigation, and the local SAR distribution can be evaluated. Local SAR maxima can be obtained by exhaustive search over all investigated subvolumes of the body model. Practical challenges arise for the adequate handling and comparing of precalculated field distributions as long as the expected combined radiofrequency excitations are still undetermined. Worst‐case approximations for local SAR lead to significant radiofrequency pulse performance limitations. Optimizing local SAR in radiofrequency pulse design using constraints for each subvolume is impractical. A method is proposed to significantly reduce the complexity without restriction to particular radiofrequency excitations. By constructing several matrices, it becomes sufficient to consider only these so‐called Virtual Observation Points for an adequate, conservative estimation of the maximum local SAR. The applied techniques involve concepts of vector optimization as well as semidefinite programming. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.
Robust fat suppression at 3T in high‐resolution diffusion‐weighted single‐shot echo‐planar imaging of human brain
Authors: Sarlls Joelle E. , Pierpaoli Carlo , Talagala S. Lalith , Luh Wen‐Ming
Published: May 2011

Single‐shot echo‐planar imaging is the most common acquisition technique for whole‐brain diffusion tensor imaging (DTI) studies in vivo. Higher field MRI systems are readily available and advantageous for acquiring DTI due to increased signal. One of the practical issues for DTI with single‐shot echo‐planar imaging at high‐field is incomplete fat suppression resulting in a chemically shifted fat artifact within the brain image. Unsuppressed fat is especially detrimental in DTI because the diffusion coefficient of fat is two orders of magnitude lower than that of parenchyma, producing brighter appearing fat artifacts with greater diffusion weighting. In this work, several fat suppression techniques were tested alone and in combination with the goal of finding a method that provides robust fat suppression and can be used in high‐resolution single‐shot echo‐planar imaging DTI studies. Combination of chemical shift saturation with slice‐select gradient reversal within a dual‐spin‐echo diffusion preparation period was found to provide robust fat suppression at 3 T. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.
Determination of regional variations and reproducibility in in vivo 1H NMR spectroscopy of the rat brain at 16.4 T
Authors: Hong Sung‐Tak , Balla David Z. , Pohmann Rolf
Published: May 2011

In vivo 1H NMR spectroscopy was used to obtain the neurochemical profile in the posterior parts of the brain, the cerebellum and the medulla oblongata in comparison to the hippocampus and the thalamus. Using small voxel sizes between 16 and 32 μl to avoid partial volume effects, most metabolites demonstrated significant regional differences except acetate, γ‐aminobutyric acid, and phosphorylcholine. Noticeable regional differences in metabolite concentrations were the significant increase of total creatine in the cerebellum and the substantial decrease of taurine in thalamus and medulla oblongata. In particular, the glycine concentration in the medulla oblongata was determined to be 4.37 ± 0.68 μmol/g (Cramér‐Rao lower bounds 7%) and thus significantly higher than in the other regions, consistent with findings reported in both in vivo 1H NMR spectroscopy and in vitro biochemical assays. Intraindividual reproducibility and interindividual variability were investigated by acquiring spectra from the thalamus of the same rats in two sessions. No prominent influence on measurement session was observed in metabolite concentrations with coefficients of variations being below 20% in 16 metabolites. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.
Improving the Delivery of Global Tobacco Control
Authors: Bitton Asaf , Green Carol , Colbert James
Published: May 2011

Tobacco control must remain a critical global health priority given the growing burden of tobacco‐induced disease in the developing world. Insights from the emerging field of global health delivery suggest that tobacco control could be improved through a systematic, granular analysis of the processes through which it is promoted, implemented, and combated. Using this framework, a critical bottleneck to the delivery of proven health promotion emerges in the role that the tobacco industry plays in promoting tobacco use and blocking effective tobacco‐control policies. This “corporate bottleneck” can also be understood as a root cause of massive disease and suffering upon vulnerable populations worldwide, for the goal of maximizing corporate profit. Naming, understanding, and responding to this corporate bottleneck is crucial to the success of tobacco‐control policies. Three case studies of tobacco‐control policy–South Africa, the Framework Convention on Tobacco Control, and Uruguay–are presented to explore and understand the implications of this analysis. Mt Sinai J Med 78:382–393, 2011. © 2011 Mount Sinai School of Medicine
Role of Students in Global Health Delivery
Authors: Finch Thomas H. , Chae Sae‐Rom , Shafaee Maryam N. , Siegel Karen R. , Ali Mohammed K. , Tomei Rachelle , Panjabi Rajesh , Kishore Sandeep P.
Published: May 2011

What role do students have in global health activities? On one hand, students have much to offer, including innovative ideas, fresh knowledge and perspective, and inspiring energy. At the same time, students lack technical credentials and may drain resources from host communities. Here, we examine the dynamic, contemporary roles of students in global health activities, including health delivery. We focus on 3 themes that guide engagement: (1) fostering an enabling policy environment (eg, toward greater health equity); (2) understanding and working within the local context and governments' needs; and (3) leading bidirectional partnerships. We next study the implications of short‐term exposure and long‐term engagement programs. We conclude with 4 recommendations on how to better equip students to engage in the next frontier of global health education and future action. Mt Sinai J Med 78:373–381, 2011. © 2011 Mount Sinai School of Medicine
New Academic Partnerships in Global Health: Innovations at Mount Sinai School of Medicine
Authors: Landrigan Philip J. , Ripp Jonathan , Murphy Ramon J. C. , Claudio Luz , Jao Jennifer , Hexom Braden , Bloom Harrison G. , Shirazian Taraneh , Elahi Ebby , Koplan Jeffrey P.
Published: May 2011

Global health has become an increasingly important focus of education, research, and clinical service in North American universities and academic health centers. Today there are at least 49 academically based global health programs in the United States and Canada, as compared with only one in 1999. A new academic society, the Consortium of Universities for Global Health, was established in 2008 and has grown significantly. This sharp expansion reflects convergence of 3 factors: (1) rapidly growing student and faculty interest in global health; (2) growing realization–powerfully catalyzed by the acquired immune deficiency syndrome epidemic, the emergence of other new infections, climate change, and globalization–that health problems are interconnected, cross national borders, and are global in nature; and (3) rapid expansion in resources for global health. This article examines the evolution of the concept of global health and describes the driving forces that have accelerated interest in the field. It traces the development of global health programs in academic health centers in the United States. It presents a blueprint for a new school‐wide global health program at Mount Sinai School of Medicine. The mission of that program, Mount Sinai Global Health, is to enhance global health as an academic field of study within the Mount Sinai community and to improve the health of people around the world. Mount Sinai Global Health is uniting and building synergies among strong, existing global health programs within Mount Sinai; it is training the next generation of physicians and health scientists to be leaders in global health; it is making novel discoveries that translate into blueprints for improving health worldwide; and it builds on Mount Sinai's long and proud tradition of providing medical and surgical care in places where need is great and resources few. Mt Sinai J Med 78:471–483, 2011. © 2011 Mount Sinai School of Medicine
Cervical Cancer Screening in Low‐ and Middle‐Income Countries
Authors: Ditzian Lauren R. , David‐West Gizelka , Maza Mauricio , Hartmann Beatrix , Shirazian Taraneh , Cremer Miriam
Published: May 2011

Cervical cancer is a leading cause of death among women in the developing world. Conventional cytology‐based cervical cancer screening programs have been largely ineffectual at reducing the cervical cancer burden in low‐resource settings. In response, alternative strategies have been tested, such as visual inspection with acetic acid (VIA) screening and human papillomavirus (HPV) DNA‐based testing. This manuscript reviews literature addressing the programmatic approaches to implementing cervical cancer screening programs in low‐resource settings, highlighting the challenges, barriers, and successes related to the use of cytology, VIA, and HPV‐DNA based screening programs. Mt Sinai J Med 78:319–326, 2011 © 2011 Mount Sinai School of Medicine
Effects of mechanical force on crystalline structure of electrospun poly(1‐butene) membranes
Authors: Lee Yujin , Lee Jieun , Kimura Disuke , Kim Byoung‐Suhk , Koh Joonseok , Kim Ick‐Soo
Published: May 2011

Fibrous poly(1‐butene) membranes were prepared from solutions using mixed solvents via electrospinning. The electrospun fibrous poly(1‐butene) membranes were stretched at elongations of 8, 16 and 24%, respectively. Scanning electron microscopy and stress–strain analysis showed that the deformation was elastic at an elongation of 8%, while plastic deformation occurred above 16%. The crystalline transformation induced by mechanical stretching was investigated using wide‐angle X‐ray diffraction. The poly(1‐butene) membrane stretched at 24% exhibited decreased diffraction intensity at 2θ = 11.8° and 18.3°, corresponding to the (200) and (213) crystalline reflections, indicating that crystalline transformation from metastable form II to either stable form I or I′ occurred due to mechanical stretching. Copyright © 2011 Society of Chemical Industry
Polymer electrolyte membrane based on poly(ether sulfone) containing binaphthyl units with pendant perfluoroalkyl sulfonic acids
Authors: Nakagawa Taijiro , Nakabayashi Kazuhiro , Higashihara Tomoya , Ueda Mitsuru
Published: May 2011

A novel poly(ether sulfone) containing binaphthyl units with pendant perfluoroalkyl sulfonic acids (BNSH‐PSA) was developed for a polymer electrolyte membrane (PEM). The BNSH‐PSA was prepared by the aromatic nucleophilic substitution reaction of 1,1′‐binaphthyl‐4,4′‐diol and 4,4′‐dichlorodiphenylsulfone, followed by the bromination with bromine, and then the Ullman coupling reaction with potassium 1,1,2,2,‐tetrafluoro‐2‐(1,1,2,2‐tetrafluoro‐2‐iodoethoxy) ethanesulfonate (PSA‐K). The ion exchange capacity (IEC) of BNSH‐PSA was estimated to be 1.91 mequiv/g, which corresponded to full conversion to the perfluroalkyl sulfonic acids. The BNSH‐PSA membrane prepared by solution casting showed high oxidative and dimensional stability. High proton conductivity comparable to the Nafion 117 membrane was accomplished in the range of 30–95% relative humidity (RH) due to the high acidity of the perfluoroalkyl sulfonic acids. Furthermore, atomic force microscopic observation supported the formation of the phase‐separated structure that the hydrophilic domains were well dispersed and connected to each other. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Equilibrium statistics of weakly slip‐linked Gaussian polymer chains
Authors: Uneyama Takashi , Horio Kazushi
Published: May 2011

We calculate the free energy and the pressure of a weakly slip‐linked Gaussian polymer chains. We show that the equilibrium statistics of a slip‐linked system is different from one of the corresponding ideal chain system without any constraints by slip‐links. It is shown that the pressure of a slip‐linked system decreases compared with the ideal system, which implies that slip‐linked chains spontaneously form aggregated cluster‐like compact structures. These are qualitatively consistent with previous theoretical analyses or multichain simulations. We also show that repulsive potentials between chains, which have been phenomenologically utilized in simulations, can cancel the artificial pressure decrease. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011
KFC2: A knowledge‐based hot spot prediction method based on interface solvation, atomic density, and plasticity features
Authors: Zhu Xiaolei , Mitchell Julie C.
Published: May 2011

Hot spots constitute a small fraction of protein–protein interface residues, yet they account for a large fraction of the binding affinity. Based on our previous method (KFC), we present two new methods (KFC2a and KFC2b) that outperform other methods at hot spot prediction. A number of improvements were made in developing these new methods. First, we created a training data set that contained a similar number of hot spot and non‐hot spot residues. In addition, we generated 47 different features, and different numbers of features were used to train the models to avoid over‐fitting. Finally, two feature combinations were selected: One (used in KFC2a) is composed of eight features that are mainly related to solvent accessible surface area and local plasticity; the other (KFC2b) is composed of seven features, only two of which are identical to those used in KFC2a. The two models were built using support vector machines (SVM). The two KFC2 models were then tested on a mixed independent test set, and compared with other methods such as Robetta, FOLDEF, HotPoint, MINERVA, and KFC. KFC2a showed the highest predictive accuracy for hot spot residues (True Positive Rate: TPR = 0.85); however, the false positive rate was somewhat higher than for other models. KFC2b showed the best predictive accuracy for hot spot residues (True Positive Rate: TPR = 0.62) among all methods other than KFC2a, and the False Positive Rate (FPR = 0.15) was comparable with other highly predictive methods. Proteins 2011. © 2011 Wiley‐Liss, Inc.
Built‐in fields in stacked InGaN/GaN quantum dots
Authors: Schulz Stefan , O'Reilly Eoin P.
Published: May 2011

The built‐in potential ϕtot of an isolated and of three stacked lens‐shaped c‐plane In0.2Ga0.8N/GaN quantum dots (QDs) is calculated using a surface integral approach. There remains disagreement about the sign of the shear strain piezoelectric coefficient e15, with more recent analysis suggesting e15 < 0. We show that with e15 < 0, the potential ϕtot changes sign outside an isolated QD, in contrast to the case with e15 > 0. This behaviour affects ϕtot in a system of stacked QDs. For small barrier thicknesses between the QDs, the potential in the central QD is strongly reduced compared to an isolated QD, independent of the sign of e15. Using e15 < 0 and small barrier thicknesses, the potential in the remaining two QDs is also slightly reduced, while for larger barrier thicknesses almost no reduction is observed.
La0.7Sr0.3MnO3 thin films deposited by pulsed laser ablation for spintronic applications
Authors: Martino Maurizio , Cesaria Maura , Caricato Anna Paola , Maruccio Giuseppe , Cola Adriano , Farella Isabella
Published: May 2011

Among spintronic materials, mixed‐valence manganite La 0.7Sr0.3MnO3 (LSMO) is widely investigated due to its half‐metal nature. LSMO thin films were grown by pulsed laser deposition (PLD) onto amorphous silica substrates heated at nearly 600 °C. An ArF excimer laser was chosen to induce ablation due to its more energetic photons compared to the other quoted excimer laser sources. Different oxygen pressures were considered in order to study the influence of oxygen on the LSMO optical and electrical properties. In this respect, the visible transparency percentage of the deposited films is found good enough for spin‐OLED applications. The absorption coefficient shows an absorption band tunable as a function of the oxygen content. Its energetic location and evolution with the oxygen content demonstrate it originates from radiative transitions between the spin‐majority bands separated by the Jahn–Teller distortion. All of this lets relate the deposition oxygen pressure to the Mn3+ ion content in each film and interpret electrical data. The 200 and 100 nm thick samples exhibit weak metallic transport behavior at room temperature with a resistivity of 4.8 and 6.9 Ω cm, respectively. Concerning the resistivity response versus temperature, the measured low metal–insulator transition temperature (150 K) is related to the sample structural features as involved by the depositions. Two different transport mechanisms describe the conductivity regime of the deposited samples, namely the small polaron variable range hopping (VRH) and the Arrhenius law.
Diurnal cycle of precipitable water vapor over Spain
Authors: Ortiz de Galisteo J. P. , Cachorro V. , Toledano C. , Torres B. , Laulainen N. , Bennouna Y. , de Frutos A.
Published: May 2011

Knowledge of the diurnal cycle of precipitable water vapor (PWV) is very limited owing to the lack of data with sufficient temporal resolution. Currently, GPS receivers have proven to be a suitable technique to determine PWV diurnal variations. In this study, the annual and seasonal diurnal cycles of PWV have been obtained from GPS data for 10 locations over Spain. The minimum value of PWV is reached approximately at the same time at all the stations, ∼0430–0530 UTC, whereas the maximum is reached in the second half of the day, but with a larger dispersion of its occurrence between stations. The annual sub‐daily variability ranges from 0.41 to 1.35 mm (3–7%). The highest values are recorded at the stations on the Mediterranean coast, with a doubling of the values of the stations on the Atlantic coast or inland. The winter cycle is quite similar at all locations, whereas in summer local effects are felt strongly, making the diurnal cycle quite different between stations. The PWV mean diurnal cycle is strongest in summer and weakest in spring, with a sub‐daily variability of 1.34 and 0.66 mm respectively. Harmonic analysis shows that the first two harmonics can explain 97% of the variance. The diurnal (24 h) harmonic explains 85% of the variance, has mean amplitude of 0.40 mm, and the peak time is from early afternoon to evening. The semi‐diurnal (12 h) harmonic is weaker, with an amplitude of 0.13 mm, and peak time between 0400 and 1000 UTC. The diurnal cycle of temperature alone would be a proxy for PWV cycle during the night, but not during the daytime. The breeze regime is the main factor responsible for the phase lag between PWV and temperature cycles during daytime. No clear correlation between the daily cycle of precipitation and PWV has been found. Copyright © 2011 Royal Meteorological Society
Linear theory of the sea breeze in a thermal wind
Authors: Drobinski Philippe , Rotunno Richard , Dubos Thomas
Published: May 2011

This article investigates the linear dynamics of the sea breeze in an along‐shore thermal wind shear. The present analysis shows that the sea‐breeze circulation is tilted towards the slanted isentropes associated with the thermal wind. At a critical value of the thermal wind shear, the tilt of the sea‐breeze circulation becomes equal to the slope of the background isentropes. The present analysis also shows a spatial shift between the heating pattern and the sea‐breeze circulation. The present linear theory is then applied to interpret measurements made in the vicinity of New York City where there is a warm‐season synoptic southwesterly jet. It is compared with observations and past numerical simulations. Agreement is found with respect to the enhanced along‐coast wind that follows the tilted isentropes, the order of magnitude of the isentrope tilt and the clockwise rotating wind hodograph showing the jet maximum peaking at 1800 solar time. There is a disagreement between theory and observations on the phase lag between the jet maximum and the cross‐shore pressure gradient maximum. However, this disagreement can reasonably be attributed to either the angle made by the synoptic jet to the coastline and/or the presence of friction. The inland spatial shift of the breeze indicated by the theory might also be indirectly confirmed by the coastal inland wind observations of a larger diurnal amplitude for a stronger synoptic jet. Copyright © 2011 Royal Meteorological Society
Multichannel RRKM study on the mechanism and kinetics of the CH3Cl + OH reaction
Authors: Dehestani Maryam , Shojaie Fahimeh
Published: May 2011

The kinetics and mechanism of the reaction of OH with CH3Cl have been theoretically studied. The potential energy surface for each possible pathway has been investigated by the G2MP2 method. The rate constants for channels leading to several products have been calculated by multichannel‐Rice‐Ramsperger‐Kassel‐Marcus (RRKM) theory over a temperature range 200–2000 K. The results show the major channel is hydrogen abstraction mechanism. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012
Correlations of carbon isotope discrimination with element and ash contents in two Sabina evergreen trees in northwest China: patterns and implications
Authors: Zhang Youfu , Chen Tuo , Liu Guangxiu , Zhang Manxiao , An Lizhe , Chen Yingwu
Published: May 2011

Foliar carbon isotope discrimination (Δ) is widely used as an integrator of physiological plant responses to environmental change. However, the relationship between foliar Δ and mineral nutrient accumulation is still not well‐known. The foliar Δ, K, Ca, Mg, Si and ash contents of S. przewalskii Kom. (SP) and S. chinensis (Lin.) Ant. (SC), two over‐winter trees distributed on high altitude plateaux and lower altitude plains, respectively, were measured at monthly intervals over two years under the same growing conditions to examine the genetic and seasonal variation in foliar nutrient concentrations in relation to foliar Δ. The foliar Δ, Mg, K and ash contents were markedly lower in SP than in SC, and the foliar Si content was significantly higher in SP than SC, while the differences in Ca contents between the two Sabina trees were not significant. There was higher foliar Δ in winter than in summer for both Sabina trees. Close negative correlations of foliar Δ with K and Mg content, and significant positive correlations between foliar Δ and Si contents, were observed in SP but not in SC. Thus, higher water‐use efficiency of SP than of SC is related to higher Si and lower Mg and K contents that have positive effects on the reduction of transpiration rates or stomatal conductances. The results obtained by the present study will advance the understanding of the adaptive strategies of mineral nutrition and water use in harsh environments. Copyright © 2011 John Wiley & Sons, Ltd.
Identification of individual acids in a commercial sample of naphthenic acids from petroleum by two‐dimensional comprehensive gas chromatography/mass spectrometry
Authors: Rowland Steven J. , West Charles E. , Scarlett Alan G. , Jones David
Published: May 2011

The identification of most individual members of the complex mixtures of carboxylic acids found in petroleum (‘naphthenic acids’) has eluded chemists for over a century; they remain unresolved by conventional gas chromatographic methods. Recently, however, we successfully used two‐dimensional comprehensive gas chromatography/mass spectrometry to identify numerous individual diamondoid acids in the naphthenic acids of oil sands process water (OSPW). We have now applied the same methods to a study of a mixture of commercially available naphthenic acids originally refined from petroleum. The results confirm that OSPW and refined petroleum contain very different distributions of acids, as noted previously, although some of the diamondoid acids recently identified in OSPW were detectable in both. Rather, two‐dimensional comprehensive gas chromatography/time‐of‐flight mass spectrometry (GCxGC/ToF‐MS) of the methyl esters of the petroleum acids and of numerous acids synthesised for comparison showed that the former comprised mainly C8–18 straight‐chain, methyl‐branched, acyclic isoprenoid, cyclohexyl and isomeric octahydropentalene, perhydroindane and perhydronaphthalene (decalin) acids. Some of the latter bicyclic acids occurred as both the non‐alkyl‐substituted isomers and the bicyclic ethanoic and propanoic acids. Also present in minor quantities was a range of phenyl carboxylic and substituted phenyl alkanoic acids, and traces of non‐acids, including trimethylnaphthalenes, again identified by comparison with the synthesised compounds. These results represent some of the first identifications of multiple individual naphthenic acids in commercial mixtures originating from petroleum and provide a basis for future studies of the petroleum geochemistry, toxicities and environmental impacts of the acids. Furthermore, characterisation of the acids will be important for improving the understanding of the role of naphthenic acids in petroleum engineering, particularly for oil pipeline deposition problems. Copyright © 2011 John Wiley & Sons, Ltd.
Distributed cross‐layer optimization for wireless regional area network‐based cognitive radio networks
Authors: Guo Wenxuan , Huang Xinming
Published: May 2011

This paper presents a study of a cross‐layer design through joint optimization of spectrum allocation and power control for cognitive radio networks (CRNs). The spectrum of interest is divided into independent channels licensed to a set of primary users (PUs). The secondary users are activated only if the transmissions do not cause excessive interference to PUs. In particular, this paper studies the downlink channel assignment and power control in a CRN with the coexistence of PUs and secondary users. The objective was to maximize the total throughput of a CRN. A mathematical model is presented and subsequently formulated as a binary integer programming problem, which belongs to the class of non‐deterministic polynomial‐time hard problems. Subsequently, we develop a distributed algorithm to obtain sub‐optimal results with lower computational complexity. The distributed algorithm iteratively improves the network throughput, which consists of several modules including maximum power calculation, excluded channel sets recording, base station throughput estimation, base station sorting, and channel usage implementation. Through investigating the impacts of the different parameters, simulation results demonstrates that the distributed algorithm can achieve a better performance than two other schemes. Copyright © 2011 John Wiley & Sons, Ltd.
Understanding online groups through social media
Authors: Barbier Geoffrey , Tang Lei , Liu Huan
Published: May 2011

Multiple fields including sociology, anthropology, and business are interested in understanding group behavior. Applying data mining techniques to social media can help provide insights into group behavior and divulge a group's characteristics by identifying a group, developing a profile for a group, revealing the sentiment of a group, and detailing a group's composition. The ability to accomplish these tasks has practical business and scientific applications such as understanding customers better and providing new insights into influence propagation, as well as the ability to accurately categorize groups over time. This paper highlights some ongoing research efforts aiming at understanding groups through social media. © 2011 John Wiley & Sons, Inc. WIREs Data Mining Knowl Discov 2011 1 330–338 DOI: 10.1002/widm.37

This article is categorized under:

Algorithmic Development > Web Mining

Application Areas > Society and Culture

Fundamental Concepts of Data and Knowledge > Data Concepts

Fundamental Concepts of Data and Knowledge > Human Centricity and User Interaction
Acceptability of Prenatal Diagnosis by a Sample of Parents of Sickle Cell Anemia Patients in Cameroon (Sub‐Saharan Africa)
Authors: Wonkam Ambroise , Njamnshi Alfred K. , Mbanya Dora , Ngogang Jeanne , Zameyo Caryl , Angwafo Fru F.
Published: May 2011

Little is known about attitudes of parents of Sickle Cell Anemia patients in sub‐Saharan Africa regarding prenatal genetic diagnosis and termination of an affected pregnancy. In this study, structured face‐to‐face interviews were conducted with a sample of 130 parents in Cameroon that had at least one living child with Sickle Cell Anemia. The majority of participants lived in urban areas (89%), were female (80%), Christian (93%), married (60.2%) in monogamous households (81.1%), were employed (61.7%), and had at least a secondary or tertiary education (82%). The majority of parents accepted the principle of prenatal genetic diagnosis for Sickle Cell Anemia (89.8%) and termination of pregnancy (62.5%). Acceptance of the principle of pregnancy termination increased with unemployment (p < .01) and single marital status (p < .05). The results of this study suggest Cameroonian parents with children affected with Sickle Cell Anemia generally accept the principles of prenatal diagnosis and in some cases termination of a pregnancy affected with Sickle Cell Anemia. Additional findings, policy and practice implications, and research recommendations are presented.
Characteristics of Eutectic Compositions of Restructured Palm Oil Olein, Palm Kernel Oil and Their Mixtures
Authors: Gold Isona L. , Ukhun M. E. , Akoh C. C.
Published: May 2011

The physico‐chemical characteristics of blends of palm olein and palm kernel oil which were further modified by chemical interesterification were studied. The slip melting points of non‐interesterified blends were 19.7, 16.2, 14.5, 14.5 and 14.4 °C while those of the chemically interesterified blends were 17.7, 16.2, 19.8, 18.7 and 18.7 °C at 40, 30, 20, 10 and 0% palm kernel oil, respectively. Chemical interesterification lowered the solid fat content of the pure samples and blends across different temperatures except 90% palm olein at 15 °C where the solid fat content was higher than for non‐interesterified samples. Palm kernel oil, palm olein and their blends before and after chemical interesterification, crystallized mainly in the β′ form. However, chemical interesterification modified the microstructure from a combination of fat particles with void regions of crystalline materials to fat particles without regions of void crystalline materials. Palm olein and palm kernel oil blends are mainly used for food preparation in Nigeria. This study has shown that there are no significant differences in the physical and chemical properties of non‐chemically interesterified and chemically interesterified blends of palm olein and palm kernel oil. This implies that blending of palm olein and palm kernel oil without chemical interesterification can provide the fluidity desirable at ambient temperatures for food applications in the tropics.
Genetisch bedingte Entwicklungsstörungen der Genitalwege
Authors: Wieacker P. , Ledig S. , Bogdanova N.
Published: May 2011

Anomalien der Genitalwege können zu Sterilität und Infertilität führen. In dieser Übersicht werden Störungen der Müller- und Wolff-Strukturen, die für die Entwicklung der weiblichen und männlichen Genitalwege verantwortlich sind, diskutiert.
Genetische Ursachen der prämaturen Ovarialinsuffizienz und Ovardysgenesie
Authors: Ledig S. , Wieacker P.
Published: May 2011

Die prämature Ovarialinsuffizienz (POI) ist durch eine Amenorrhö vor dem 40. Lebensjahr und einen hypergonadotropen Hypogonadismus gekennzeichnet. Die Prävalenz für Frauen mit 40 Jahren liegt bei 1%. Die Ovardysgenesie, welche durch einen kompletten Follikelverlust vor der Geburt charakterisiert ist, kann als die schwerste Manifestation einer POI angesehen werden. Die POI tritt in der Mehrzahl isoliert auf, kann aber auch Teil einer syndromalen Erkrankung sein. Neben exogenen Faktoren kommen auch genetische Faktoren wie Chromosomenaberrationen, monogenetische Defekte und eine polygen-multifaktorielle Genese in Frage. Inzwischen sind mehr als 30 Gene bekannt, deren Mutationen zur POI führen. Dennoch ist in der Mehrzahl der Fälle die Ätiologie der POI weiterhin unbekannt.
Störungen der männlichen Gonadendifferenzierung
Authors: Wieacker P. , Ledig S.
Published: May 2011

Die XY-Gonadendysgenesie ist ein heterogenes Krankheitsbild und kann durch eine Entwicklungsstörung der Urogenitalleiste zur bipotenten Gonade oder durch eine Störung der bipotenten Gonade zum Hoden bedingt sein. Dementsprechend können Gene der frühen Gonadendifferenzierung wie WT1 und SF1 von solchen der Testis-Differenzierung wie SRY, SOX9, DMRT, DAX1, WNT4, DHH, CBX2, TSPYL1, ATRX und ARX unterschieden werden. Bei der kompletten XY-Gonadendysgenesie sind die Müller-Strukuren, aber keine Wolff-Strukturen vorhanden, und es besteht ein hypergonadotroper Hypogonadismus. Bei der partiellen XY-Gonadendysgenesie können Residuen von Müller- und Wolff-Strukturen sowie eine Virilisierung des äußeren Genitales vorhanden sein. In ungefähr einem Drittel der Fälle von XY-Gonadendysgenesie besteht eine syndromale Form, wobei Leitsymptome auf die zugrunde liegende Ursache hinweisen. Mutationen in Genen, die typischerweise zu syndromalen Formen der XY-Gonadendysgenesie führen, können allerdings auch eine nichtsyndromale Form hervorrufen.
Pervasive Cognitive Impairment in Acute Rehabilitation Inpatients Without Brain Injury
Authors: Woods Adam J. , Mark Victor W. , Pitts Anthony C. , Mennemeier Mark
Published: May 2011

Objective

To establish feasibility for the hypothesis that patients in acute rehabilitation who are hospitalized for disorders not known to involve cerebral injury can have significant cognitive impairment.

Design

A comparison of performances on neuropsychological tests between 2 samples of subjects: inpatients in an acute rehabilitation hospital without known cerebral disease and normal community‐dwelling persons.

Setting

Acute inpatient rehabilitation hospital.

Patients and Participants

Nineteen hospitalized patients without delirium who were screened for pre‐existing cerebral and psychiatric illness, dementia, and dependency in basic self‐care skills before hospitalization. Eighteen community‐dwelling persons who were not different in terms of age and education served as the control group.

Methods

Participants completed 10 commonly used neuropsychological tests of executive, language, and memory functions. Data were analyzed by using multivariate analysis of variance.

Main Outcome Measurements

Raw scores on the 10 neuropsychological tests.

Results

Hospitalized patients performed significantly worse on 9 of 10 tests than community‐dwelling participants. Older hospitalized participants had significantly greater cognitive impairment than younger hospitalized participants, which suggested increased susceptibility to effects of hospitalization on cognition.

Conclusions

Patients hospitalized without brain injury, and especially elderly patients, should be carefully monitored for cognitive deficits that may affect posthospitalization quality of living. Further research is needed to determine whether the cognitive deficits in such patients persist after discharge and affect functional independence, and to identify mechanisms for the deficits. Furthermore, the use of hospitalized participants without brain injury as control subjects in neuropsychological studies of brain injury should be balanced with an additional comparison group of matched, neurologically healthy, normal subjects who live in the community to control for cognitive impairments that are associated with acute hospitalization.
Periodicity of hermitianK-groups
Authors: Berrick A. J. , Karoubi M. , Østvær P. A.
Published: May 2011

Bott periodicity for the unitary and symplectic groups is fundamental to topologicalK-theory. Analogous to unitary topologicalK-theory, for algebraicK-groups with finite coefficients, similar results are consequences of the Milnor and Bloch-Kato conjectures, affirmed by Voevodsky, Rost and others. More generally, we prove that periodicity of the algebraicK-groups for any ring implies periodicity for the hermitianK-groups, analogous to orthogonal and symplectic topologicalK-theory.

The proofs use in an essential way higherKSC-theories, extending those of Anderson and Green. They also provide an upper bound for the higher hermitianK-groups in terms of higher algebraicK-groups.

We also relate periodicity to étale hermitianK-groups by proving a hermitian version of Thomason's étale descent theorem. The results are illustrated in detail for local fields, rings of integers in number fields, smooth complex algebraic varieties, rings of continuous functions on compact spaces, and group rings.
Corrigendum: C*-envelopes of tensor algebras for multivariable dynamics
Authors: Davidson Kenneth R. , Roydor Jean
Published: May 2011

There is an unfortunate error in Theorem 4.1 of our paper. However, the statement of the theorem remains true with a correct construction of adding a tail to enlarge the dynamical system.
Hippocampus, space, and memory
Authors: Olton David S. , Becker James T. , Handelmann Gail E.
Published: May 2011

We examine two different descriptions of the behavioral functions of the hippocampal system. One emphasizes spatially organized behaviors, especially those using cognitive maps. The other emphasizes memory, particularly working memory, a short-term memory that requires iexible stimulus-response associations and is highly susceptible to interference. The predictive value of the spatial and memory descriptions were evaluated by testing rats with damage to the hippocampal system in a series of experiments, independently manipulating the spatial and memory characteristics of a behavioral task. No dissociations were found when the spatial characteristics of the stimuli to be remembered were changed; lesions produced a similar deficit in both spatial and nonspatial test procedures, indicating that the hippocampus was similarly involved regardless of the spatial nature of the task. In contrast, a marked dissociation was found when the memory requirements were altered. Rats with lesions were able to perform accurately in tasks that could be solved exclusively on the basis of reference memory. They performed at chance levels and showed no signs of recovery even with extensive postoperative training in tasks that required working memory. In one experiment all the characteristics of the reference memory and working memory procedures were identical except the type of memory required. Consequently, the behavioral dissociation cannot be explained by differences in attention, motivation, response inhibition, or the type of stimuli to be remembered. As a result of these experiments we propose that the hippocampus is selectively involved in behaviors that require working memory, irrespective of the type of material (spatial or nonspatial) that is to be processed by that memory.
Neurolinguistics must be computational
Authors: Arbib Michael A. , Caplan David
Published: May 2011

We provide a threefold taxonomy of models in neurolinguistics: faculty models, which embrace the work of classical connectionists and holists and of such modern workers as Geschwind; process models, which are exemplified by the work of Luria, and which fractionate psycholinguistic tasks and ascribe the components to particular brain regions; and representational models, which use specific linguistic representations to build a psycholinguistic analysis of aphasic performance. We argue that further progress requires that neurolinguistics become more computational, using techniques from Artificial Intelligence to model the cooperative computation underlying language processing at a level of detail consonant with linguistic representations. Finally, we note that current neurolinguistics makes virtually no contact with the synapse-cell-circuit level of analysis characteristic of twentieth-century neuroscience. We suggest that the cooperative computation models we envisage provide the necessary intermediary between current neurolinguistic analysis and the utilization of the fruits of modern neuroanatomy, neurochemistry, and neurophysiology.
Précis ofUnified theories of cognition
Authors: Newell Allen
Published: May 2011

The book presents the case that cognitive science should turn its attention to developing theories of human cognition that cover the full range of human perceptual, cognitive, and action phenomena. Cognitive science has now produced a massive number of high-quality regularities with many microtheories that reveal important mechanisms. The need for integration is pressing and will continue to increase. Equally important, cognitive science now has the theoretical concepts and tools to support serious attempts at unified theories. The argument is made entirely by presenting an exemplar unified theory of cognition both to show what a real unified theory would be like and to provide convincing evidence that such theories are feasible. The exemplar is SOAR, a cognitive architecture, which is realized as a software system. After a detailed discussion of the architecture and its properties, with its relation to the constraints on cognition in the real world and to existing ideas in cognitive science, SOAR is used as theory for a wide range of cognitive phenomena: immediate responses (stimulus-response compatibility and the Sternberg phenomena); discrete motor skills (transcription typing); memory and learning (episodic memory and the acquisition of skill through practice); problem solving (cryptarithmetic puzzles and syllogistic reasoning); language (sentence verification and taking instructions); and development (transitions in the balance beam task). The treatments vary in depth and adequacy, but they clearly reveal a single, highly specific, operational theory that works over the entire range of human cognition, SOAR is presented as an exemplar unified theory, not as the sole candidate. Cognitive science is not ready yet for a single theory – there must be multiple attempts. But cognitive science must begin to work toward such unified theories.
A psychobiological theory of attachment
Authors: Kraemer Gary W.
Published: May 2011

This article describes a neurobiological basis for the “first attachment” of the primate infant to its caretaker. The infant normally internalizes a neurobiological “image” of the behavioral and emotional characteristics of its caregiver that later regulates important features of its brain function. Current models of sensorimotor analysis and its relation to emotion suggest that sensorimotor systems are also habit and memory systems, their functional status and lability regulated in part by biogenic amine systems. The intertwined development of neural and social functions can sometimes go awry. If the attachment process fails or the caregiver is incompetent, the infant may become socially dysfunctional. This helps explain the developmental psychopathology and later vulnerability to adult psychopathology that result from disruptions of social attachment.
Informal and formal home-care use among older adults in Europe: can cross-national differences be explained by societal context and composition?
Authors: SUANET BIANCA , VAN GROENOU MARJOLEIN BROESE , VAN TILBURG THEO
Published: May 2011

Cross-national comparisons employed welfare state classifications to explain differences in care use in the European older population. Yet these classifications do not cover all care-related societal characteristics and limit our understanding of which specific societal characteristics are most important. Using the Survey of Health, Ageing and Retirement (second wave, 2006–07), the effect of societal determinants relating to culture, welfare state context and socio-economic and demographic composition on informal and formal care use of older adults in 11 European countries was studied. Multinomial multi-level regression analyses showed that, in addition to individual determinants, societal determinants are salient for understanding care use. In countries with fewer home-based services, less residential care, more informal care support and women working full time, older adults are more likely to receive informal care only. Older adults are more likely to receive only formal home care or a combination of formal and informal care in countries with more extensive welfare state arrangements (i.e. more home-based services, higher pension generosity), whereas the odds of receiving a combination of informal and formal care are also larger in countries that specify a legal obligation to care for parents. We tentatively conclude that the incorporation of societal determinants rather than commonly used welfare state classifications results in more understanding of the societal conditions that determine older adults’ care use.
Commercial harvesting and regeneration of epiphytic macrolichen communities in the Western Ghats, India
Authors: MOLLEMAN LUCAS , BOEVE SIL , WOLF JAN , OOSTERMEIJER GERARD , DEVY SOUBADRA , GANESAN RENGAIAN
Published: May 2011

Non-timber forest products form a substantial contribution to the livelihood of many rural communities worldwide. In the Western Ghats, India, epiphytic macrolichens are harvested by Paliyan tribes to generate supplementary income. Paliyan tribes employ two harvesting methods: shallow harvesting, with a minimum of attached bark substratum, and deep harvesting, which exposes the sapwood. To evaluate the regeneration of the lichen community in terms of species diversity, abundance and composition, 320 bark samples of up to 50 cm2were collected from bark patches where lichens had been harvested previously, as shown by bark scars. Samples selected represented four host tree species, both harvesting methods and seven one-year intervals of time since harvesting. In each case, the field guide estimated sample age, and peer-testing proved these estimates to be reliable up to an age of seven years. Seven years after harvesting, the lichen community showed noteworthy regeneration capacity in terms of total lichen coverage and species richness. However, to assess the risk of local species loss in the long-term, any harvesting should include continuous monitoring of lichen species composition. Since shallow harvesting resulted in a swifter recovery of species abundance and richness compared with deep harvesting, harvesters should preferentially employ the shallow harvesting method.