bluuebunny/crossref_metadata_2025 huggingface dataset:
STUDY OF BIOTIC EVOLUTIONARY MECHANISMS BASED ON THE MULTI-AGENT PARRONDO'S GAMES
Authors: YE YE , XIE NENG-GANG , WANG LIN-GANG , MENG RUI , CEN YU-WAN
Published: March 2012

The paper tries to explain the biological evolutionary mechanism based on Parrondo's games. The multi-agent Parrondo's games proposed include game A and game B. Game A, a zero-sum game, reflects the interactive relationship of competition or cooperation between individuals. A two-dimensional lattice network is used to represents the spatial carrier of interactive relationship. Game B, a negative-sum game, reflects the environmental effect on survival evolution of individuals. Three patterns which are based on individual survival states, on historical experience and on neighbors' environment are adopted to represent the mechanisms. The simulation results show that: (1) A zero-sum game (game A) and a losing game (game B) combined could produce a winning result. Improvement of the average fitness of the population represents the essence that Parrondo's paradox is counterintuitive. The special structure of game B reflects the ratcheting effect that natural environment has on biological evolution where both competition and cooperation are successful evolution directions. (2) The ratcheting effect of the environment-based pattern is the strongest. In the course of biological evolution, neighbors' environment usually uses an efficient mechanism to guide the evolution. Just because of the neighbors' environment-based guidance, a coevolution model is formed where individuals compose the population which composes the community and the community composes the ecosystem which composes the biosphere. (3) Competition can raise the average fitness of the population. Therefore, competition may be an adaptive behavior on the population level. (4) Research to-date has shown that the necessary condition of producing cooperation is that the cost is less than profit. While the results in this paper show that a zero-sum game can also give rise to cooperation, which can bring about positive gain for the whole population.
APPLICATION OF EMPIRICAL MODE DECOMPOSITION COMBINED WITH k-NEAREST NEIGHBORS APPROACH IN FINANCIAL TIME SERIES FORECASTING
Authors: LIN AIJING , SHANG PENGJIAN , FENG GUOCHEN , ZHONG BO
Published: March 2012

The purpose of this paper is to forecast the daily closing prices of stock markets based on the past sequences. In this paper, keeping in mind the recent trends and the limitations of previous researches, we proposed a new technique, called empirical mode decomposition combined with k-nearest neighbors (EMD–KNN) method, in forecasting the stock index. EMD–KNN takes the advantages of the KNN and EMD. To demonstrate that our EMD–KNN method is robust, we used the new technique to forecast four stock index time series at a specific time. Detailed experiments are implemented for both of the proposed forecasting models, in which EMD–KNN, KNN method and ARIMA are compared. The results demonstrate that the proposed EMD–KNN model is more successful than KNN method and ARIMA in predicting the stock closing prices.
THE CENTER OF THE CATEGORY OF BIMODULES AND DESCENT DATA FOR NONCOMMUTATIVE RINGS
Authors: AGORE A. L. , CAENEPEEL S. , MILITARU G.
Published: March 2012

Let A be an algebra over a commutative ring k. We compute the center of the category of A-bimodules. There are six isomorphic descriptions: the center equals the weak center, and can be described as categories of noncommutative descent data, comodules over the Sweedler canonical A-coring, Yetter–Drinfeld type modules or modules with a flat connection from noncommutative differential geometry. All six isomorphic categories are braided monoidal categories: in particular, the category of comodules over the Sweedler canonical A-coring A ⊗ A is braided monoidal. We provide several applications: for instance, if A is finitely generated projective over k then the category of left End k(A)-modules is braided monoidal and we give an explicit description of the braiding in terms of the finite dual basis of A. As another application, new families of solutions for the quantum Yang–Baxter equation are constructed: they are canonical maps Ω associated to any right comodule over the Sweedler canonical coring A ⊗ A and satisfy the condition Ω3 = Ω. Explicit examples are provided.
PURE PROJECTIVITY AND PURE INJECTIVITY OVER FORMAL TRIANGULAR MATRIX RINGS
Authors: HAGHANY A. , MAZROOEI M. , VEDADI M. R.
Published: March 2012

Over a formal triangular matrix ring we study pure injective, pure projective and locally coherent modules. Some applications are then given, in particular the (J-)coherence of the ring [Formula: see text] is characterized whenever BM is flat.
PROJECTIVE SPECIAL LINEAR GROUPS PSL4(q) ARE DETERMINED BY THE SET OF THEIR CHARACTER DEGREES
Authors: NGUYEN HUNG NGOC , TONG-VIET HUNG P. , WAKEFIELD THOMAS P.
Published: March 2012

Let G be a finite group and let cd (G) be the set of all irreducible complex character degrees of G. It was conjectured by Huppert in Illinois J. Math.44 (2000) that, for every non-abelian finite simple group H, if cd (G) = cd (H) then G ≅ H × A for some abelian group A. In this paper, we confirm the conjecture for the family of projective special linear groups PSL 4(q) with q ≥ 13.
AN IMPROVEMENT OF A BOUND OF GREEN
Authors: NIROOMAND PEYMAN , RUSSO FRANCESCO G.
Published: March 2012

A p-group G of order pn (p prime, n ≥ 1) satisfies a classic Green's bound log p |M(G)| ≤ ½n(n - 1) on the order of the Schur multiplier M(G) of G. Ellis and Wiegold sharpened this restriction, proving that log p |M(G)| ≤ ½(d - 1)(n + m), where |G′| = pm(m ≥ 1) and d is the minimal number of generators of G. The first author has recently shown that log p |M(G)| ≤ ½(n + m - 2)(n - m - 1) + 1, improving not only Green's bound, but several other inequalities on |M(G)| in literature. Our main results deal with estimations with respect to the bound of Ellis and Wiegold.
AN INFINITE SYSTEM OF HYPERCOMPLEX NUMBERS
Authors: SUNDHEIM PAUL
Published: March 2012

A system of hypercomplex numbers is defined for each dimension that is a power of 2. In each of these dimensions, the numbers are associative and commutative but their advantages lie in the ease of multiplication, how closely their properties mirror the properties of the complex numbers in 2 dimensions as well as the location and properties of the zero divisors. In addition, the basis forms a group under multiplication providing a multiplication table that relates all of the roots of –1 and real and non-real roots of 1.
TWISTED DRINFELD DOUBLES AND REPRESENTATIONS OF A HOPF ALGEBRA
Authors: BAI LI , WANG SHUANHONG
Published: March 2012

In this paper, we consider a class of non-commutative and non-cocommutative Hopf algebras Hp(α, q, m) and then show that these Hopf algebras can be realized as a quantum double of certain Hopf algebras with respect to Hopf skew pairings (Ap(q, m), Bp(q, m), τα). Furthermore, using the Hopf skew pairing with appropriate group homomorphisms: ϕ : π → Aut (Ap(q, m)) and ψ : π → Aut (Bp(q, m)), we construct a twisted Drinfeld double D(Ap(q, m), Bp(q, m), τ; ϕ, ψ) which is a Turaev [Formula: see text]-coalgebra, where the group [Formula: see text] is a twisted semi-direct square of a group π. Then we obtain its quasi-triangular Turaev [Formula: see text]-coalgebra structure. We also study irreducible representations of Hp(1, q, m) and construct a corresponding R-matrix. Finally, we introduce the notion of a left Yetter–Drinfeld category over a Turaev group coalgebra and show that such a category is a Turaev braided group category by a direct proof, without center construction. As an application, we consider the case of the quasi-triangular Turaev [Formula: see text]-coalgebra structure on our twisted Drinfeld double.
BALINSKY–NOVIKOV SUPERALGEBRAS AND SOME INFINITE-DIMENSIONAL LIE SUPERALGEBRAS
Authors: PEI YUFENG , BAI CHENGMING
Published: March 2012

In this paper, we recall the Balinsky–Novikov (BN) superalgebras and revisit the approach of constructing an infinite-dimensional Lie superalgebra by a kind of affinization of a BN superalgebra. As an example, we give an explicit construction of Beltrami and Green–Schwarz–Witten (GSW) algebras from two isomorphic BN superalgebras, respectively, which proves that they are isomorphic as a direct consequence. Moreover, we consider the central extensions of the infinite-dimensional Lie superalgebras induced from BN superalgebras through certain bilinear forms on their corresponding BN superalgebras.
ON IRREDUCIBLE FACTORS OF POLYNOMIALS OVER COMPLETE FIELDS
Authors: KHANDUJA SUDESH K. , KUMAR SANJEEV
Published: March 2012

Let (K, v) be a complete rank-1 valued field. In this paper, we extend classical Hensel's Lemma to residually transcendental prolongations of v to a simple transcendental extension K(x) and apply it to prove a generalization of Dedekind's theorem regarding splitting of primes in algebraic number fields. We also deduce an irreducibility criterion for polynomials over rank-1 valued fields which extends already known generalizations of Schönemann Irreducibility Criterion for such fields. A refinement of Generalized Akira criterion proved in Khanduja and Khassa [Manuscripta Math.134(1–2) (2010) 215–224] is also obtained as a corollary of the main result.
ON SEXTIC TRINOMIALS WITH GALOIS GROUP C6, S3 OR C3 × S3
Authors: BROWN STEPHEN C. , SPEARMAN BLAIR K. , YANG QIDUAN
Published: March 2012

We characterize irreducible trinomials x6 + Ax + B with coefficients in a number field K which have Galois group C6, S3 or C3 × S3. This characterization relates these trinomials to the K-rational points on a genus 2 curve. We determine these trinomials explicitly in the case K = ℚ.
PRIMITIVE CENTRAL IDEMPOTENTS OF RATIONAL GROUP ALGEBRAS
Authors: JANSSENS GEOFFREY
Published: March 2012

We give a description of the primitive central idempotents of the rational group algebra ℚG of a finite group G. Such a description is already investigated by Jespers, Olteanu and del Río, but some unknown scalars are involved. Our description also gives answers to their questions.
UNITARY REPRESENTATIONS FOR THE SCHRÖDINGER–VIRASORO LIE ALGEBRA
Authors: ZHANG XIUFU , TAN SHAOBIN
Published: March 2012

In this paper, conjugate-linear anti-involutions and unitary Harish-Chandra modules over the Schrödinger–Virasoro algebra are studied. It is proved that there are only two classes conjugate-linear anti-involutions over the Schrödinger–Virasoro algebra. The main result of this paper is that a unitary Harish-Chandra module over the Schrödinger–Virasoro algebra is simply a unitary Harish-Chandra module over the Virasoro algebra.
COLORED QUIVERS OF TYPE A AND THE CELL-GROWTH PROBLEM
Authors: TORKILDSEN HERMUND ANDRÉ
Published: March 2012

We use a geometric description of m-cluster categories of Dynkin type A to count the number of colored quivers in the m-mutation class of quivers of Dynkin type A. This is related to angulations of polygons and the cell-growth problem.
PRESENTATIONS AND MODULE BASES OF INTEGER-VALUED POLYNOMIAL RINGS
Authors: ELLIOTT JESSE
Published: March 2012

Let D be an integral domain with quotient field K. For any set X, the ring Int (DX) of integer-valued polynomials onDX is the set of all polynomials f ∈ K[X] such that f(DX) ⊆ D. Using the t-closure operation on fractional ideals, we find for any set X a D-algebra presentation of Int (DX) by generators and relations for a large class of domains D, including any unique factorization domain D, and more generally any Krull domain D such that Int (D) has a regular basis, that is, a D-module basis consisting of exactly one polynomial of each degree. As a corollary we find for all such domains D an intrinsic characterization of the D-algebras that are isomorphic to a quotient of Int (DX) for some set X. We also generalize the well-known result that a Krull domain D has a regular basis if and only if the Pólya–Ostrowski group of D (that is, the subgroup of the class group of D generated by the images of the factorial ideals of D) is trivial, if and only if the product of the height one prime ideals of finite norm q is principal for every q.
ON QUANTIZED GENERALIZED INTERSECTION MATRIX ALGEBRAS ASSOCIATED TO 2-FOLD AFFINIZATION OF CARTAN MATRICES
Authors: LV RUI , TAN YOUJUN
Published: March 2012

Let A[2] be the generalized intersection matrix (gim for short) given by the 2-fold affinization of a Cartan matrix of ADE type and [Formula: see text] its covering matrix. We show that the quantized gim algebra given by A[2] is isomorphic to a right coideal subalgebra of the quantized enveloping algebra associated to [Formula: see text], which is a quantum analogue of S. Berman's theorem on involutory subalgebras.
AN IDEAL THEORETIC APPROACH TO COMPLETE PARTITE ZERO-DIVISOR GRAPHS OF POSETS
Authors: ALIZADEH M. , MAIMANI H. R. , POURNAKI M. R. , YASSEMI S.
Published: March 2012

In this paper, we characterize complete partite zero-divisor graphs of posets via the ideals of the posets. In particular, for complete bipartite zero-divisor graphs, we give a characterization based on the prime ideals of the posets.
MATERIAL ELEMENT MODEL AND DISSIPATIVE PROCESSES FOR FERRIMAGNETIC CRYSTALS WITH A NON-EUCLIDEAN STRUCTURE
Authors: DOLFIN MARINA , FRANCAVIGLIA MAURO , RESTUCCIA LILIANA
Published: March 2012

In a previous paper we outlined a geometric model for the thermodynamical description of ferrimagnetic crystals with a non-Euclidean structure. Applying a geometrization technique based on a model for magnetizable deformable media earlier introduced by Maugin, starting from an appropriate dynamical system on the fiber bundle of processes for simple material elements of these media, the expressions of the entropy function and the entropy 1-form were obtained. In this contribution we deepen the study of this geometrical model. We give a detailed description of the media under consideration, we introduce the transformation induced by the process and, applying the closure conditions for the entropy 1-form, we work out the necessary conditions for the existence of the entropy function. The derivation of the entropy 1-form is the starting point to introduce an extended thermodynamical phase space. Finally, from the exploitation of the Clausius–Duhem inequality, we derive, using Maugin's techniques, the residual dissipation inequality and the heat equation in the first and second form.
DYNAMICS IN NON-COMMUTATIVE SPACES AND GENERALIZATIONS
Authors: MARTINA LUIGI
Published: March 2012

Resorting to the Lagrange–Souriau 2-form formalism, a wide class of systems are derived in non-commuting and/or non-canonical variables, nor the Darboux theorem can be helpful, because of the gauge character of all phase-space variables. As a paradigmatic example, the motion of a charged particle in a magnetic monopole field in the presence of a momentum space monopole is considered.
A FAMILY OF GENERALIZED KAC–MOODY ALGEBRAS AND DEFORMATION OF MODULAR FORMS
Authors: KIM HENRY H. , LEE KYU-HWAN
Published: March 2012

We develop an analogue of Gindikin–Karpelevich formula for a family of generalized Kac–Moody algebras, attached to Borcherds–Cartan matrices consisting of only one positive entry in the diagonal. As an application, we obtain a deformation of Fourier coefficients of modular forms such as the modular j-function and Ramanujan τ-function.
ON THE CRITICAL NUMBER OF FINITE GROUPS OF ORDER pq
Authors: WANG Q. H. , ZHUANG J. J.
Published: March 2012

Let G be a finite group and S be a subset of G\{0}. We call S an additive basis of G if every element of G can be expressed as a sum over a non-empty subset in some order. Let cr (G) be the smallest integer t such that every subset of G\{0} of cardinality t forms an additive basis of G. In this paper, we determine cr (G) for all groups G of order pq, where p, q are primes.
THE DYNAMICAL BEHAVIOR OF NON-SMOOTH SYSTEM WITH IMPULSIVE CONTROL STRATEGIES
Authors: TAN YUAN-SHUN , LIANG JU-HUA , TANG SAN-YI
Published: March 2012

Non-smooth system including impulsive strategies at both fixed and unfixed times are analyzed. For the model with fixed impulsive effects, the global stability of pest eradication periodic solution and the dominance of dynamic behavior are investigated. This indicates that the model with fixed moments has the potential to protect the natural enemies from extinction, but under some conditions may also serve to extinction of the pest. The second model is constructed according to the practices of IPM, that is, when the pest population reaches the economic injury level, a combination of biological, cultural, and chemical tactics that reduce pests to tolerable levels is used. Numerical investigations imply that there are several different types of periodic solutions and their maximum amplitudes are always less than the given economic threshold. The results also show that the time series at which the IPM strategies are applied are quite complex, which means that the application and realization of IPM in practice are very difficult.
ELECTRONIC, MAGNETIC, AND MECHANICAL PROPERTIES OF LINE-DEFECT EMBEDDED GRAPHENE NANORIBBONS: A FIRST-PRINCIPLES STUDY
Authors: GUAN ZHAOYONG , WU XIAOJUN , LI QUNXIANG
Published: March 2012

We use first-principles method to investigate the electronic, magnetic, and mechanical properties of graphene nanoribbons (GNRs) with extended line defect. Particular attention has been placed on zigzag GNR with 5-8-5 line defect and armchair GNR with 4-8 line defect. The results show that the band gaps of GNRs can be effectively tuned by line defect, which depend on both their widths and the position of defect. The line-defect embedded GNRs are either metals or semiconductor with markedly reduced band gap. The band-gap reduction is attributed to the defect-induced impurity states. In particular, the metallic line-defect embedded zigzag GNRs are ferromagnetic at ground state, while those semiconducting ones are antiferromagnetic. Upon the line-defect embedded armchair GNRs, the band gaps vary periodically with the increasing widths. Our results imply the potential applications of line-defect embedded GNRs at nanoscale electronics.
COMPUTATIONAL SIMULATIONS OF NANOSTRUCTURED SOLAR CELLS
Authors: WANG BAOMIN , GAO TONGCHUAN , LEU PAUL W.
Published: March 2012

Simulation methods are vital to the development of next-generation solar cells such as plasmonic, organic, nanophotonic, and semiconductor nanostructure solar cells. Simulations are predictive of material properties such that they may be used to rapidly screen new materials and understand the physical mechanisms of enhanced performance. They can be used to guide experiments or to help understand results obtained in experiments. In this paper, we review simulation methods for modeling the classical optical and electronic transport properties of nanostructured solar cells. We discuss different techniques for light trapping with an emphasis on silicon nanostructures and silicon thin films integrated with nanophotonics and plasmonics.
Sialadenoma Papilliferum: Clinical Misdiagnosis with a Histological Decree
Authors: Anuradha A. , Ram Prasad V. V. S. , Kashyap Bina , Srinivas Vijay
Published: March 2012

Sialadenoma papilliferum is a rare salivary gland tumor clinically resembling papilloma originating probably from the excretory duct. It is characterized by a biphasic growth pattern of exophytic squamous component and endophytic glandular component. We report a rare case of sialadenoma papilliferum in the floor of the mouth with epithelial dysplasia with pertinent review of literature. The present case highlights the importance of keeping sialadenoma papilliferum as a differential diagnosis of exophytic papilliferous oral lesions and the need to explore the etiology and malignant potential of the tumor.
Simple Modification of Karl-Fischer Titration Method for Determination of Water Content in Colored Samples
Authors: Tavčar Eva , Turk Erika , Kreft Samo
Published: March 2012

The most commonly used technique for water content determination is Karl-Fischer titration with electrometric detection, requiring specialized equipment. When appropriate equipment is not available, the method can be performed through visual detection of a titration endpoint, which does not enable an analysis of colored samples. Here, we developed a method with spectrophotometric detection of a titration endpoint, appropriate for moisture determination of colored samples. The reaction takes place in a sealed 4 ml cuvette. Detection is performed at 520 nm. Titration endpoint is determined from the graph of absorbance plotted against titration volume. The method has appropriate reproducibility (), accuracy, and linearity ().
The Effect of Path and Beginning Time of Ascending on Incidence of Acute Mountain Sickness around Mount Damavand in Iran (5671 m)
Authors: Alizadeh Reza , Ziaee Vahid , Frooghifard Lotf-Ali , Mansournia Mohammad-Ali , Aghsaeifard Ziba
Published: March 2012

Background. This study was designed to evaluate the incidence of acute mountain sickness (AMS) occurring on different climbing routes on Mount Damavand and the effect of beginning time of ascent in Iranian trekkers.Methods. This study was a descriptive cohort investigation, performed in summer 2007. All trekkers who ascended Mount Damavand from northern, western, eastern, and southern paths and passed 4200 m altitude were included in the study. Two questionnaires were completed for each trekker (personal information and Lake Louise score questionnaire). Multiple logistic regression analysis was used to explore the independent predicting variables for AMS.Results. Overall incidence rate of AMS was 53.6%. This rate was the highest in south route (61.5%) (P<0.001). There was no difference in the incidence of AMS on other paths. AMS history, AMS history on Damavand, the beginning time of climbing, sleeping at 4200 m altitude, and home altitude had significant effect on AMS incidence, but by multiple logistic regression analysis south route and AMS history on Mount Damavand had positive effect on incidence of AMS (P=0.019andP<0.001).Conclusion. The path and the beginning time of ascent can affect incidence of AMS. The risk of occurrence of AMS was 1.9 times as large for trekkers who ascended from southern route.
The Impact of Herbal Drug Use on Adverse Drug Reaction Profiles of Patients on Antiretroviral Therapy in Zimbabwe
Authors: Mudzviti Tinashe , Maponga Charles C. , Khoza Star , Ma Qing , Morse Gene D.
Published: March 2012

Background. The main objective was to determine the impact of herbal drug use on adverse drug reactions in patients on antiretroviral therapy (ART).Methodology. Patients receiving first-line ART from the national roll-out program participated in this cross-sectional study. Participants were interviewed and a data collection sheet was used to collect information from the corresponding medical record.Results. The majority (98.2%) of participants were using at least one herbal drug together with ART. The most common herbal remedies used wereAllium Sativum(72.7%),Bidens pilosa(66.0%),Eucalyptus globulus(52.3%),Moringa oleifera(44.1%),Lippia javanica(36.3%), andPeltoforum africanum(34.3%). Two indigenous herbs,Musakavakadzi(OR=0.25; 95% CI 0.076–0.828) andPeltoforum africanum(OR=0.495; 95% CI 0.292–0.839) reduced the occurrence of adverse drug events.Conclusions. The use of herbal drugs is high in the HIV-infected population and there is need for pharmacovigilance programs to recognize the role they play in altering ADR profiles.
Deep Level Saturation Spectroscopy
Authors: Gavryushin Vladimir
Published: March 2012

We review the “Deep Level Saturation Spectroscopy” (DLSS) as the nonlinear method to study the deep local defects in semiconductors. The essence of a method is determined by the processes of sufficiently strong laser modulation (up to saturation) of quasistationar two-step absorption of the probe light via deep levels (DLs). DLSS is based on nonequilibrium processes of the optically induced population changes for deep levels which lead to the changes in an impurity absorption. This method allows us the separation of the spectral contributions from different deep centers (even in the case of their full spectral overlap), on the basis of the difference of their optical activity (photon capture cross-sections) and of their electroactivity difference (carriers capture coefficients). As shown, DLSS is allowed to determine directly the main set of phenomenological parameters (cross-sections, concentration, bound energy, etc.) for deep local defects, their content and energy position in the band gap. Some important aspects of DLSS were shown also: the possibility to connect directly the measured data to the local centers which are participating in radiative recombination, and also the possibility to study directly the phonon relaxation processes in the localized states of deep defects.
Role of in Asthma and Nonasthmatic Eosinophilic Bronchitis
Authors: Sastre Beatriz , del Pozo Victoria
Published: March 2012

Eosinophilic bronchitis is a common cause of chronic cough, which like asthma is characterized by sputum eosinophilia, but unlike asthma there is no variable airflow obstruction or airway hyperresponsiveness. Several studies suggest that prostaglandins may play an important role in orchestrating interactions between different cells in several inflammatory diseases such as asthma. PGE2is important because of the multiplicity of its effects on immune response in respiratory diseases; however, respiratory system appears to be unique in that PGE2has beneficial effects. We described that the difference in airway function observed in patients with eosinophilic bronchitis and asthma could be due to differences in PGE2production. PGE2present in induced sputum supernatant from NAEB patients decreases BSMC proliferation, probably due to simultaneous stimulation of EP2 and EP4 receptors with inhibitory activity. This protective effect of PGE2may not only be the result of a direct action exerted on airway smooth-muscle proliferation but may also be attributable to the other anti-inflammatory actions.
Unprotected Sex with Injecting Drug Users among Iranian Female Sex Workers: Unhide HIV Risk Study
Authors: Ahmadi Khodabakhsh , Rezazade Majid , Nafarie Mohammad , Moazen Babak , Yarmohmmadi Vasel Mosaieb , Assari Shervin
Published: March 2012

Purpose. To assess the prevalence and associated factors of unprotected sex with injecting drug users (IDUs) among a sample of female sex workers (FSWs) in Iran.Methods. This cross-sectional study included 144 FSWs who were interviewed as a part of Unhide HIV Risk Study, a national behavioral survey focusing on various high-risk populations, including IDUs, FSWs, and Men who have Sex with Men (MSMs) in 2009. The survey was conducted in eight provinces in Iran using respondent-driven sampling. Participants’ sociodemographic status, HIV knowledge, and HIV attitude were analyzed via logistic regression to determine the predictors of unprotected sex with IDU(s) during the past month.Results. Nineteen percent of FSWs reported at least one occasion of unprotected sex with IDU(s) in the month preceding the study. Higher educational level (OR=−0.653, 95%CI=-1.192to −0.115), perceived HIV risk (OR=−1.047, 95%CI=-2.076to −0.019), and perceived family intimacy during childhood (OR=−1.104, 95%CI=-1.957to −0.251) were all independently associated with lower odds of having unprotected sex with IDU(s) in the month preceding the study. Age, marital status, living condition, HIV knowledge, and perceived behavioral control did not affect the odds of FSWs having sex with IDUs.Conclusion. Perceived HIV risk, which is a modifiable factor, seems to be a promising target for harm reduction interventions amongst Iranian female sex workers. Data presented here may aid in reducing or eliminating the role of sex workers as a bridge for HIV transmission from IDUs to the general population in Iran.
Synthesis, Growth, and Electrical Transport Properties of Pure and -Doped Triglycine Sulphate Crystal
Authors: Khanum Farhana , Podder Jiban
Published: March 2012

Pure triglycine sulphate (TGS) and LiSO4-doped TGS crystals were grown from aqueous solution by natural evaporation method. The grown crystals were characterized by UV-vis spectroscopy, electrical conductivity () measurement, dielectric studies, microhardness, and thermogravimetry/differential thermal analysis. Pure TGS and LiSO4-doped TGS crystals were found highly transparent and full faced. The direct current conductivity is found to increase with temperature as well as dopant concentrations. Curie temperature remains the same for pure and doped crystals, but dielectric constant and dielectric loss increase with dopant concentration. The Vicker’s microhardness of the LiSO4-doped TGS crystals along (001) face is found higher than that of pure TGS crystals. Etching studies illustrate the quality of the doped crystal. The experimental results evidence the suitability of the grown crystal for optoelectronic applications.
Cadmium and Zinc Concentration in Grain of Durum Wheat in Relation to Phosphorus Fertilization, Crop Sequence and Tillage Management
Authors: Gao Xiaopeng , Grant Cynthia A.
Published: March 2012

Field experiments were conducted at two locations in Manitoba, Canada, to determine the effect of crop rotation, phosphorus (P) fertilization and tillage on grain yield and grain concentrations of Cd and Zn in durum wheat (Triticum durumL.). Compared to conventional tillage (CT), reduced tillage (RT) management decreased grain Cd and increased grain yield and grain Zn in half of the site-years. The type of preceding crops of spring wheat-flax or canola-flax had little influence. Rate and timing of P application had little effect on grain Cd, but increasing P rate tended to decrease grain Zn. No interactive effect was detected among tested factors. Grain Zn was not related to grain Cd, but positively to other nutrients such as Fe, Mn, P, Ca, K, and Mg. Both grain Zn and Fe correlated positively with grain protein content, suggesting protein may represent a sink for micronutrients. The study suggested that the tillage management may have beneficial effects on both grain yield and quality. Phosphorus fertilizer can remain available for subsequent crops and high annual inputs in the crop sequence may decrease crop grain Zn. Understanding the environment is important in determining the impact of agricultural management on agronomic and nutrient traits.
Chemical Integration of Myrmecophilous Guests inAphaenogasterAnt Nests
Authors: Lenoir Alain , Chalon Quentin , Carvajal Ana , Ruel Camille , Barroso Ángel , Lackner Tomáš , Boulay Raphaël
Published: March 2012

Social insect nests provide a safe and favourable shelter to many guests and parasites. InAphaenogaster senilisnests many guests are tolerated. Among them we studied the chemical integration of two myrmecophile beetles,Sternocoelis hispanus(Coleoptera: Histeridae) andChitosa nigrita(Coleoptera: Staphylinidae), and a silverfish. Silverfishes bear low quantities of the host hydrocarbons (chemical insignificance), acquired probably passively, and they do not match the colony odour. Both beetle species use chemical mimicry to be accepted; they have the same specific cuticular hydrocarbon profile as their host. They also match the ant colony odour, but they keep some specificity and can be recognised by the ants as a different element.Sternocoelisare always adopted in other conspecific colonies ofA. seniliswith different delays. They are adopted in the twin speciesA. ibericabut never inA. simonelliiorA. subterranea. They are readopted easily into their mother colony after an isolation of different durations until one month. After isolation they keep their hydrocarbons quantity, showing that they are able to synthesize them. Nevertheless, their profile diverges from the host colony, indicating that they adjust it in contact with the hosts. This had never been demonstrated before in myrmecophile beetles. We suggest that the chemical mimicry ofSternocoelisis the result of a coevolution withA. seniliswith a possible cleaning symbiosis.
Vascular Occlusion or Not during Liver Resection: The Continuing Story
Authors: Hoekstra Lisette T. , van Trigt Jessica D. , Reiniers Megan J. , Busch Oliver R. , Gouma Dirk J. , van Gulik Thomas M.
Published: March 2012

Background: Vascular occlusion can be applied during liver resection to reduce blood loss. Herein, we provide an update of the current evidence concerning vascular occlusion. Methods: A systematic literature search was conducted to review the effects of liver in- and outflow occlusion techniques during liver resection, focusing on blood loss and hepatic ischemia-reperfusion injury. Results: The Pringle maneuver (PM) is effective in controlling blood loss; however, there is no indication for routine vascular clamping during hepatic resection in uncomplicated patients. During complex resections and in patients with abnormal liver parenchyma, the intermittent PM is preferred over continuous clamping. Total hepatic vascular exclusion (THVE) is indicated only in resection of tumors involving the inferior caval vein or the caval hepatic junction. THVE can be applied with the preservation of caval vein flow. This mode of selective hepatic vascular exclusion results in less blood loss in combination with the PM. Conclusion: If clamping is necessary during complex resections or in abnormal liver parenchyma, intermittent PM is advised. THVE or selective hepatic vascular exclusion may be considered in tumors involving the inferior caval vein or the caval hepatic junction. There is no evidence supporting the use of ischemic preconditioning, maintenance of a low central venous pressure or of pharmacological interventions during liver resection.
Posthepatectomy Bile Leakage: How to Manage
Authors: Hoekstra Lisette T. , van Gulik Thomas M. , Gouma Dirk J. , Busch Oliver R.
Published: March 2012

Background: Biliary leakage after liver resection continues to be reported. Management of bile leakage has changed in recent years, with nowadays non-surgical procedures as the preferred treatment. Methods: Biliary leakage and management were assessed in 381 patients who underwent liver resection between January 2005 and April 2011. Results: The overall rate of biliary leakage after liver resection was 5.0%, with a higher incidence in patients who had undergone concomitant hepaticojejunostomy (HJ; 13.6 vs. 3.2%). Hospital stay (p = 0.047), major resections (p = 0.018), operation time (p = 0.011), and relaparotomy (p = 0.002) were risk factors for postoperative bile leakage. Multivariate analysis identified relaparotomy as an independent factor (OR 4.216, p = 0.034). Bile leakage in patients without HJ (n = 10) was managed in 6 patients by percutaneous transhepatic biliary drainage (PTD), and in 3 patients by endoscopic drainage. One patient was treated surgically. All patients with an HJ and postoperative bile leakage (n = 9) underwent PTD. Conclusion: The incidence of posthepatectomy biliary leakage has decreased over time, while PTD and endoscopic stenting are effective treatment modalities. PTD is the treatment of choice in bile leakage after resection combined with HJ.
Laparoscopic Liver Resection: Is There a Learning Curve?
Authors: Robinson Stuart M. , Hui Kei Y. , Amer Aimen , Manas Derek M. , White Steve A.
Published: March 2012

Background: Laparoscopic liver resection (LLR) is becoming an accepted treatment option for resecting both benign and malignant tumours. However, it is critical that the laparoscopic approach does not compromise the technical quality of the liver resection. The aim of this paper was to review the learning curve of LLR in a specialist HPB unit. Methods: A prospective database was searched to identify patients undergoing LLR over a 4-year period. To assess the effect of the learning curve on outcome, the series was evaluated during two eras – early versus late. Results: Fifty-one (27 males, median age 68 years) patients were identified with 37 having LLR. The most common indication was for colorectal liver metastases, and the most common procedure was a non-anatomical metastectomy. Changes in management decisions (n = 14) occurred more frequently during the first era (9 vs. 5; p > 0.05). More patients underwent right hepatectomy in the late group (3 vs. 1; p < 0.05). There did not appear to be any difference in duration of surgery for laparoscopic left lateral resection between the eras (200 vs. 240 min; p > 0.05) which probably reflected trainees performing more operations during the late era. Left hepatectomy was most commonly performed in the early era compared to more right hepatectomies during the late era. Conclusion: LLR is associated with a learning curve, but once this has been overcome it can be safely utilised in the management of malignant liver lesions even for major resections, surgical training and simultaneous resections.
Identification of Directed Influence: Granger Causality, Kullback-Leibler Divergence, and Complexity
Authors: Seghouane Abd-Krim , Amari Shun-ichi
Published: March 2012

Detecting and characterizing causal interdependencies and couplings between different activated brain areas from functional neuroimage time series measurements of their activity constitutes a significant step toward understanding the process of brain functions. In this letter, we make the simple point that all current statistics used to make inferences about directed influences in functional neuroimage time series are variants of the same underlying quantity. This includes directed transfer entropy, transinformation, Kullback-Leibler formulations, conditional mutual information, and Granger causality. Crucially, in the case of autoregressive modeling, the underlying quantity is the likelihood ratio that compares models with and without directed influences from the past when modeling the influence of one time series on another. This framework is also used to derive the relation between these measures of directed influence and the complexity or the order of directed influence. These results provide a framework for unifying the Kullback-Leibler divergence, Granger causality, and the complexity of directed influence.
Dynamic State and Parameter Estimation Applied to Neuromorphic Systems
Authors: Neftci Emre Ozgur , Toth Bryan , Indiveri Giacomo , Abarbanel Henry D. I.
Published: March 2012

Neuroscientists often propose detailed computational models to probe the properties of the neural systems they study. With the advent of neuromorphic engineering, there is an increasing number of hardware electronic analogs of biological neural systems being proposed as well. However, for both biological and hardware systems, it is often difficult to estimate the parameters of the model so that they are meaningful to the experimental system under study, especially when these models involve a large number of states and parameters that cannot be simultaneously measured. We have developed a procedure to solve this problem in the context of interacting neural populations using a recently developed dynamic state and parameter estimation (DSPE) technique. This technique uses synchronization as a tool for dynamically coupling experimentally measured data to its corresponding model to determine its parameters and internal state variables. Typically experimental data are obtained from the biological neural system and the model is simulated in software; here we show that this technique is also efficient in validating proposed network models for neuromorphic spike-based very large-scale integration (VLSI) chips and that it is able to systematically extract network parameters such as synaptic weights, time constants, and other variables that are not accessible by direct observation. Our results suggest that this method can become a very useful tool for model-based identification and configuration of neuromorphic multichip VLSI systems.
Neural Information Processing with Feedback Modulations
Authors: Zhang Wenhao , Wu Si
Published: March 2012

Descending feedback connections, together with ascending feedforward ones, are the indispensable parts of the sensory pathways in the central nervous system. This study investigates the potential roles of feedback interactions in neural information processing. We consider a two-layer continuous attractor neural network (CANN), in which neurons in the first layer receive feedback inputs from those in the second one. By utilizing the intrinsic property of a CANN, we use a projection method to reduce the dimensionality of the network dynamics significantly. The simplified dynamics allows us to elucidate the effects of feedback modulation analytically. We find that positive feedback enhances the stability of the network state, leading to an improved population decoding performance, whereas negative feedback increases the mobility of the network state, inducing spontaneously moving bumps. For strong, negative feedback interaction, the network response to a moving stimulus can lead the actual stimulus position, achieving an anticipative behavior. The biological implications of these findings are discussed. The simulation results agree well with our theoretical analysis.
Simple Deterministically Constructed Cycle Reservoirs with Regular Jumps
Authors: Rodan Ali , Tiňo Peter
Published: March 2012

A new class of state-space models, reservoir models, with a fixed state transition structure (the “reservoir”) and an adaptable readout from the state space, has recently emerged as a way for time series processing and modeling. Echo state network (ESN) is one of the simplest, yet powerful, reservoir models. ESN models are generally constructed in a randomized manner. In our previous study (Rodan & Tiňo, 2011 ), we showed that a very simple, cyclic, deterministically generated reservoir can yield performance competitive with standard ESN. In this contribution, we extend our previous study in three aspects. First, we introduce a novel simple deterministic reservoir model, cycle reservoir with jumps (CRJ), with highly constrained weight values, that has superior performance to standard ESN on a variety of temporal tasks of different origin and characteristics. Second, we elaborate on the possible link between reservoir characterizations, such as eigenvalue distribution of the reservoir matrix or pseudo-Lyapunov exponent of the input-driven reservoir dynamics, and the model performance. It has been suggested that a uniform coverage of the unit disk by such eigenvalues can lead to superior model performance. We show that despite highly constrained eigenvalue distribution, CRJ consistently outperforms ESN (which has much more uniform eigenvalue coverage of the unit disk). Also, unlike in the case of ESN, pseudo-Lyapunov exponents of the selected optimal CRJ models are consistently negative. Third, we present a new framework for determining the short-term memory capacity of linear reservoir models to a high degree of precision. Using the framework, we study the effect of shortcut connections in the CRJ reservoir topology on its memory capacity.
Conditional Association
Authors: Seth Sohan , Príncipe José C.
Published: March 2012

Estimating conditional dependence between two random variables given the knowledge of a third random variable is essential in neuroscientific applications to understand the causal architecture of a distributed network. However, existing methods of assessing conditional dependence, such as the conditional mutual information, are computationally expensive, involve free parameters, and are difficult to understand in the context of realizations. In this letter, we discuss a novel approach to this problem and develop a computationally simple and parameter-free estimator. The difference between the proposed approach and the existing ones is that the former expresses conditional dependence in terms of a finite set of realizations, whereas the latter use random variables, which are not available in practice. We call this approach conditional association, since it is based on a generalization of the concept of association to arbitrary metric spaces. We also discuss a novel and computationally efficient approach of generating surrogate data for evaluating the significance of the acquired association value.
The View from the Tower of Crossing Sails: Ji Yun's Female Informants
Authors: Huntington Rania
Published: March 2012

This paper explores the role of women as alleged sources for Qing dynasty zhiguai (tales of the strange) collections, particularly Ji Yun's (1724-1805) Yuewei caotang biji (Jottings from the Cottage of Close Scrutiny). Tracing circulation of narratives across both single-sex and mixed-sex networks sheds light on those networks, and on shared or divergent lore and interpretations as tales are cooperatively assembled. The absence or presence of female narrators or listeners in tales focused on women's behavior also reveals differing articulations of vice and virtue.
Making 'Opposite-sex Love' in Print: Discourse and Discord in Linglong Women's Pictorial Magazine, 1931-1937
Authors: Wang Gary
Published: March 2012

This is a case study that examines desire and its regulation in the Shanghai magazine publication Linglong of the 1930s. It highlights representational tensions in the construction of heteronormative marriage, a regulatory measure that contained the prospects of female autonomy during a period of flux. The study uses an integrated, or “horizontal,” method of reading, which regards journal issues as collectively authored texts and emphasizes the spatial relation and interplay of printed content. Writings and images are referred to as integral aspects of representation to illustrate the ways in which heteronormativity is covertly challenged at the same time that same-sex love and the rejection of marriage are forcefully stigmatized. A special focus of the analysis is an examination of how the valorization of heterosexual love is matched by vociferous attacks on men and idealizations of female bonds, which are at times valued over relations with men. Insinuations of alternative sensibilities and desires are also highlighted, especially the magazine's celebration of masculine women in images.
Courtship Communication in Meadow Katydids: Female Preference for Large Male Vibrations
Authors: de Luca Paul , Morris Glenn
Published: March 2012

Males of the katydid Conocephalus nigropleurum (Orthoptera: Tettigoniidae) shake their body to produce a substrate-borne vibratory signal in the context of courtship and mate attraction. We measured the physical parameters of this tremulation signal and then tested its effectiveness in eliciting taxis by virgin females. We also investigated the role of these vibrations in the choices made by females of larger males as mates. A search for correlations between male weight and vibratory signal parameters revealed a strong negative relationship to inter-pulse interval (ipi). In two-choice playback experiments females oriented towards tremulation vibration when it was the only vibration stimulus provided. In further playback experiments females also distinguished conspecific tremulation from a control vibration. When offered simultaneous presentations of tremulation signals that differed in ipi, females moved toward the stimulus with the shorter ipi indicative of a larger male. This is the first study to demonstrate that tremulation signalling by male katydids encodes critical information on body size, and that females discriminate among different vibratory signals in favour of those indicating a larger male.