bluuebunny/crossref_metadata_2025 huggingface dataset:
Influenza Virus Sequence Feature Variant Type Analysis: Evidence of a Role for NS1 in Influenza Virus Host Range Restriction
Authors: Noronha Jyothi M. , Liu Mengya , Squires R. Burke , Pickett Brett E. , Hale Benjamin G. , Air Gillian M. , Galloway Summer E. , Takimoto Toru , Schmolke Mirco , Hunt Victoria , Klem Edward , García-Sastre Adolfo , McGee Monnie , Scheuermann Richard H.
Published: March 2012

Genetic drift of influenza virus genomic sequences occurs through the combined effects of sequence alterations introduced by a low-fidelity polymerase and the varying selective pressures experienced as the virus migrates through different host environments. While traditional phylogenetic analysis is useful in tracking the evolutionary heritage of these viruses, the specific genetic determinants that dictate important phenotypic characteristics are often difficult to discern within the complex genetic background arising through evolution. Here we describe a novel influenza virus sequence feature variant type (Flu-SFVT) approach, made available through the public Influenza Research Database resource (www.fludb.org), in which variant types (VTs) identified in defined influenza virus protein sequence features (SFs) are used for genotype-phenotype association studies. Since SFs have been defined for all influenza virus proteins based on known structural, functional, and immune epitope recognition properties, the Flu-SFVT approach allows the rapid identification of the molecular genetic determinants of important influenza virus characteristics and their connection to underlying biological functions. We demonstrate the use of the SFVT approach to obtain statistical evidence for effects of NS1 protein sequence variations in dictating influenza virus host range restriction.
Isolation and Characterization of a Novel Betacoronavirus Subgroup A Coronavirus, Rabbit Coronavirus HKU14, from Domestic Rabbits
Authors: Lau Susanna K. P. , Woo Patrick C. Y. , Yip Cyril C. Y. , Fan Rachel Y. Y. , Huang Yi , Wang Ming , Guo Rongtong , Lam Carol S. F. , Tsang Alan K. L. , Lai Kenneth K. Y. , Chan Kwok-Hung , Che Xiao-Yan , Zheng Bo-Jian , Yuen Kwok-Yung
Published: March 2012

We describe the isolation and characterization of a novelBetacoronavirussubgroup A coronavirus, rabbit coronavirus HKU14 (RbCoV HKU14), from domestic rabbits. The virus was detected in 11 (8.1%) of 136 rabbit fecal samples by reverse transcriptase PCR (RT-PCR), with a viral load of up to 108copies/ml. RbCoV HKU14 was able to replicate in HRT-18G and RK13 cells with cytopathic effects. Northern blotting confirmed the production of subgenomic mRNAs coding for the HE, S, NS5a, E, M, and N proteins. Subgenomic mRNA analysis revealed a transcription regulatory sequence, 5′-UCUAAAC-3′. Phylogenetic analysis showed that RbCoV HKU14 formed a distinct branch amongBetacoronavirussubgroup A coronaviruses, being most closely related to but separate from the speciesBetacoronavirus 1. A comparison of the conserved replicase domains showed that RbCoV HKU14 possessed <90% amino acid identities to most members ofBetacoronavirus 1in ADP-ribose 1″-phosphatase (ADRP) and nidoviral uridylate-specific endoribonuclease (NendoU), indicating that RbCoV HKU14 should represent a separate species. RbCoV HKU14 also possessed genomic features distinct from those of otherBetacoronavirussubgroup A coronaviruses, including a unique NS2a region with a variable number of small open reading frames (ORFs). Recombination analysis revealed possible recombination events during the evolution of RbCoV HKU14 and members ofBetacoronavirus 1, which may have occurred during cross-species transmission. Molecular clock analysis using RNA-dependent RNA polymerase (RdRp) genes dated the most recent common ancestor of RbCoV HKU14 to around 2002, suggesting that this virus has emerged relatively recently. Antibody against RbCoV was detected in 20 (67%) of 30 rabbit sera tested by an N-protein-based Western blot assay, whereas neutralizing antibody was detected in 1 of these 20 rabbits.
Barriers and bridges to infection prevention and control: results of a qualitative case study of a Netherlands' surgical unit
Authors: Backman Chantal , Marck Patricia B , Krogman Naomi , Taylor Geoff , Sales Anne , Bonten Marc J M , Gigengack-Baars Ada C M
Published: March 2012

Objectives

The objectives of the study are to observe the overall work environment including infection prevention and control (IP&C) practices on the target surgical unit; to analyse the policies and procedures in the hospital and unit environments; to analyse the barriers and bridges to IP&C that practitioners identify in visual narratives of their unit environment and to collect monthly specific IP&C-related anonymised data.

Design

In this qualitative case study analysis, a socio-ecological approach on health systems informed the research design and provided a framework to better understand the complexity of implementing effective IP&C.

Setting

The study was conducted on a surgical unit at a Netherlands' hospital that reported successful reductions in the prevalence of targeted multidrug-resistant organisms.

Methods

Research methods included unit observations (n=3), review of relevant policies and procedures, five practitioner-led photo walkabouts of the unit (n=7), three photo elicitation focus groups with practitioners (n=13) and the review of related IP&C data.

Results

The findings indicate some conditions and processes present that may influence the low prevalence of multidrug-resistant organisms, including the ‘search and destroy’ active surveillance strategy, low occupancy rates, a centralised bed cleaning system and the presence of an active grass roots Hygiene in Practice group, which engages practitioners in several ongoing activities to promote IP&C on the units.

Conclusions

Further research on the benefits of practitioner-led community of practices on IP&C practices such as the Hygiene in Practice group is also recommended. Additional case studies to compare theses practices with other acute care hospital around the world would be a valuable way to better understand what IP&C programmes are most effective in which contexts and for what reasons. Further data are available by contacting the primary author directly.
Foreign field hospitals after the 2010 Haiti earthquake: how good were we?
Authors: Gerdin Martin , Wladis Andreas , von Schreeb Johan
Published: March 2012

Objective

To assess the timing and activities of foreign field hospitals (FFH) deployed during the first month after the Haiti earthquake and to evaluate adherence to WHO/Pan American Health Organization (PAHO) guidelines. Results were compared with data from past sudden-onset disasters.

Methods

A systematic attempt was made to contact all relief actors within the health care sector involved in the 12 January through 12 February 2010 FFH deployment. This was done using an email-based questionnaire and a web survey. In addition, the authors undertook a literature review using PubMed and the Google search engine between March 2010 and May 2011. The authors contacted key informants and agencies identified by direct observations in the field by email or phone.

Results

A total of 44 FFH were identified. The first FFH was operational on day two post-earthquake. The number of FFH beds peaked at about 3300 on day 17 post-earthquake. During the first month, the authors estimate that FFH conducted no more than 12 000 major surgical operations. While 25% of the FFH adhered to either WHO/PAHO first essential deployment requirements, none followed both requirements of WHO/PAHO. Compared with the 2005 earthquake in Pakistan, twice as many FFH provided medical care, resulting in three times more FFH beds.

Conclusions

The present study suggests that more FFH were sent to Haiti than to any previous sudden-onset disasters, but due to lack of data and transparency it remains impossible to determine to what extent did the first wave of FFH do any good in Haiti.
Survey of trainee attitudes to preparation for and participation in the FCEM examination
Authors: Cooper Jamie G , Rutherford Elaine , Hamer Wayne
Published: March 2012

Introduction and aims

In the UK, specialist trainees in emergency medicine are required to pass the Fellowship of the College of Emergency Medicine (FCEM). This examination assesses clinical knowledge, attitudes and skills, management principles, critical appraisal, and the ability to search medical literature and synthesise information. The aims of this study were to ascertain what resources trainees felt were most valuable in preparation for the FCEM and to obtain trainee feedback on the running of the FCEM.

Methods

A questionnaire was developed in conjunction with the TSC into nine parts covering all aspects of preparation for and experience of sitting the FCEM. Email addresses of those trainees who had sat the FCEM examination in 2006 and 2007 were provided by the CEM and questionnaires were sent electronically to recipients. Responses were collated and analysed using Microsoft Excel.

Results

There was a response rate of 42% (86/203), of whom about three-quarters felt well prepared for the FCEM. The most highly valued resources for exam preparation were practice questions, private study and small group work. A yearly mock FCEM examination was felt to be important by those who had such access and local trainer involvement in exam preparation was perceived significant for success.

Conclusions

Training programmes should make sure that facilities and expertise are available at a local level to allow trainees to have access to everything that is considered important in order to pass the FCEM.
HIGH LEVEL OF ARSENIC REAFFIRMED FOR HUMAN HAIRS IN MONGOLIA
Authors: MURAO S. , SERA K. , TUMENBAYAR B. , SAIJAA N. , URAMGAA J.
Published: March 2012

We have analyzed the hair of inhabitant of a district in Mongolia where the arsenic contamination is doubted. The study area includes a village where the authors noticed possible arsenic contamination in 2004 (S. Murao, B. Tumenbayar, K. Sera, S. Futatsugawa and T. Waza, Finding of high level arsenic for Mongolian villagers' hair, Int. J. PIXE 14 (2004) 125–131). The investigation team visited each family, explained the purpose of visit, obtained their consent, and cut the untreated virgin hairs. The result reaffirmed high arsenic concentration, up to 11ppm, for most of the subjects. Since the arsenic anomaly in the study area is observed regardless the occupation, it is highly probable that the area is contaminated on a regional scale.
PECULIAR ANISOTROPIC STATIONARY SPHERICALLY SYMMETRIC SOLUTION OF EINSTEIN EQUATIONS
Authors: GALLO EMANUEL , MORESCHI OSVALDO M.
Published: March 2012

Motivated by studies on gravitational lenses, we present an exact solution of the field equations of general relativity, which is static and spherically symmetric, has no mass but has a nonvanishing spacelike components of the stress–energy–momentum tensor. In spite of its strange nature, this solution has nontrivial descriptions of gravitational effects. We show that the main aspects found in the dark matter phenomena can be satisfactorily described by this geometry. We comment on the relevance it could have to consider nonvanishing spacelike components of the stress–energy–momentum tensor ascribed to dark matter.
DYNEIN'S NETWORK OF CHEMOMECHANICAL MOTOR CYCLES
Authors: SHEN WEIBO , WANG ZIQING , WANG GUODONG
Published: March 2012

An eight-state network model of dynein's chemomechanical motor cycles is developed, in which the states of an effective single dynein head are represented by the number of ATP binding at the primary site and the number of ATP binding at other three secondary sites. The binding and unbinding of ATP, as well as the hydrolysis of ATP and the reverse process, are characterized by transition rates between certain states. Our results show that the stall force of dynein increases fast with ATP up to 1 mM ATP, beyond which it increases slowly to a saturated value, and that load and ATP concentration can adjust the step size of dynein, i.e., dynein can shift gears according to conditions. These results are in agreement with experiments [R. Mallik, B. C. Carter, S. A. Lex, S. J. King and S. P. Gross, Nature427, 649 (2004)].
INTELLIGENT POWER MANAGEMENT FOR EMBEDDED WI-FI DEVICES
Authors: HONG WEIYIN , KUANG XIN , SHEN JIANHUA , WEI TONGQUAN
Published: March 2012

With the increasing deployment of Wi-Fi devices in portable embedded systems, the low power design at system level has attracted considerable research attention in the recent past. In this paper, based on hardware features and software architecture of the embedded Wi-Fi devices, we focus on dynamic power management, dynamic frequency scaling, and their influences upon the system power and performance. We propose effective and realizable system power management solution and application modes under various application requirements, such as response, bandwidth, and speed. Experimental results show that the proposed solutions can achieve significant energy savings.
ADAPTIVE FAULT-TOLERANT TASK SCHEDULING FOR REAL-TIME ENERGY HARVESTING SYSTEMS
Authors: ZHU LINJIE , WEI TONGQUAN , CHEN XIAODAO , GUO YONGHE , HU SHIYAN
Published: March 2012

Fault tolerance and energy have become important design issues in multiprocessor system-on-chips (SoCs) with the technology scaling and the proliferation of battery-powered multiprocessor SoCs. This paper proposed an energy-efficient fault tolerance task allocation scheme for multiprocessor SoCs in real-time energy harvesting systems. The proposed fault-tolerance scheme is based on the principle of the primiary/backup task scheduling, and can tolerate at most one single transient fault. Extensive simulated experiment shows that the proposed scheme can save up to 30% energy consumption and reduce the miss ratio to about 8% in the presence of faults.
STOCHASTIC INFORMATION GRADIENT ALGORITHM WITH GENERALIZED GAUSSIAN DISTRIBUTION MODEL
Authors: CHEN BADONG , PRINCIPE JOSE C. , HU JINCHUN , ZHU YU
Published: March 2012

This paper presents a parameterized version of the stochastic information gradient (SIG) algorithm, in which the error distribution is modeled by generalized Gaussian density (GGD), with location, shape, and dispersion parameters. Compared with the kernel-based SIG (SIG-Kernel) algorithm, the GGD-based SIG (SIG-GGD) algorithm does not involve kernel width selection. If the error is zero-mean, the SIG-GGD algorithm will become the least mean p-power (LMP) algorithm with adaptive order and variable step-size. Due to its well matched density estimation and automatic switching capability, the proposed algorithm is favorably in line with existing algorithms.
PRIVACY-PRESERVING OLAP FOR ACCURATE ANSWER
Authors: ZHU YOUWEN , HUANG LIUSHENG , TAKAGI TSUYOSHI , ZHANG MINGWU
Published: March 2012

Recently, growing privacy concerns have received more and more attention and it becomes a significant topic on how to preserve private-sensitive information from being violated in distributed cooperative computation. In this paper, we first propose a novel-general privacy-preserving online analytical processing model based on secure multiparty computation. Then, based on the new model, two schemes to privacy-preserving count aggregate query over both horizontally partitioned data and vertically partitioned data are proposed. Additionally, we also propose several efficient subprotocols that serve as the basic secure buildings. Furthermore, we analyze correctness, security, communication cost, and computation complexity of our proposed protocols, and show that the new schemes are secure, having good linear complexity and that the query results are exactly accurate.
NONLINEAR OBSERVER FOR INDUCTION MOTOR TO IMPROVE EFFICIENCY AND DYNAMIC STABILITY ANALYSIS IN FOC METHOD
Authors: ALEMI-ROSTAMI M. , ABRISHAMIFAR ADIB
Published: March 2012

Control of induction motor due to its nonlinear property is one of the most popular research topics recently. Vector control based algorithms which are used for proper functioning estimate the rotor speed and magnetic flux. In many applications, flux and speed are estimated without using sensors. Thus, in these cases, it is necessary to obtain speed and flux by measuring voltage and current. In this paper, a nonlinear observer for estimating motor parameters based on Lyapunov function is presented. Using the Lyapunov theory, inputs regulating system and control system are earned which improve system performance. Simulation and experimental results are included to validate the effectiveness of the proposed control scheme under possible uncertainties and different reference trajectories. These results show the advantages of the proposed observer in control of induction motor transient performances. The merits of the proposed control system are also indicated comparing with a traditional optimal control system.
BIANCHI I SOLUTIONS OF EFFECTIVE QUADRATIC GRAVITY
Authors: MÜLLER DANIEL , DE DEUS JULIANO A.
Published: March 2012

It is believed that soon after the Planck time, Einstein's general relativity theory should be corrected to an effective quadratic theory. Numerical solutions for the anisotropic generalization of the Friedmann "flat" model E3 for this effective gravity are given. It must be emphasized that although numeric, these solutions are exact in the sense that they depend only on the precision of the machine. The solutions are identified asymptotically in a certain sense. It is found solutions which asymptote de Sitter space, Minkowski space and a singularity. This work is a generalization for nondiagonal spatial metrics of a previous result obtained by one of us and a collaborator for Bianchi I spaces.
CRYPTANALYSIS ON SECURE FRACTAL IMAGE CODING BASED ON FRACTAL PARAMETER ENCRYPTION
Authors: YUEN CHING-HUNG , WONG KWOK-WO
Published: March 2012

The vulnerabilities of the selective encryption scheme for fractal image coding proposed by Lian et al.1 are identified. By comparing multiple cipher-images of the same plain-image encrypted with different keys, the positions of unencrypted parameters in each encoded block are located. This allows the adversary to recover the encrypted depth of the quadtree by observing the length of each matched domain block. With this depth information and the unencrypted parameters, the adversary is able to reconstruct an intelligent image. Experimental results show that some standard test images can be successfully decoded and recognized by replacing the encrypted contrast scaling factor and brightness offset with specific values. Some remedial approaches are suggested to enhance the security of the scheme.
FIRST-PRINCIPLES STUDY OF THE ADSORPTION AND DIFFUSION OF O2 ON A Si(001) SURFACE
Authors: YANG CHUN , YANG CHONG , HUANG PING , LIANG XIAO QIN
Published: March 2012

We apply a first-principles molecular-dynamics method based on the density functional theory to calculate several initial configurations of an O2 molecule adsorbed on a Si(001) surface. The bonding processing, adsorption energy, dynamic track, and diffusion coefficient are investigated. The results indicate that the adsorption process may be divided into four stages: physical adsorption, chemical adsorption early stage, chemical adsorption late stage, and the superficial stable state. The Si=O structure, the Si–O–Si surface oxygen-bridge structure, and the Si–O–Si oxygen-bridge structure where oxygen atoms are inserted into the backbonds between the surface and the second layer of silicon atoms in the stable adsorption structures, are beneficial to the formation of the silica tetrahedral structure. We conclude that the remarkable difference between the diffusion coefficients during the physical adsorption stage leads to different diffusion paths, which results in the formation of two concomitant stable structures in the early process of silicon surface oxidation.
TWO DIPODAL PYRIDIN-PYRAZOL DERIVATIVES AS EFFICIENT INHIBITORS OF MILD STEEL CORROSION IN HCL SOLUTION — PART I: ELECTROCHEMICAL STUDY
Authors: CISSE M. B. , ZERGA B. , El KALAI F. , TOUHAMI M. EBN , SFAIRA M. , TALEB M. , HAMMOUTI B. , BENCHAT N. , EL KADIRI S. , BENJELLOUN A. TOUIMI
Published: March 2012

The effect of two pyridin-pyrazol derivatives, N-[(3,5-dimethyl-1H-pyrazol)methyl]pyridine-2-amine (TB5) and 5-bromo-N-[(3,5-dimethyl-1H-pyrazol)methyl]pyridine-2-amine (TB6), newly synthesized, on the corrosion of mild steel in 1.0 M HCl was investigated by weight-loss and various electrochemical techniques. Results obtained reveal that these pyridin-pyrazol derivatives perform excellently as corrosion inhibitors for mild steel in hydrochloric solution. Polarization curves showed that both TB5 and TB6 are mixed-type inhibitors in acidic medium. A kinetic study of steel in uninhibited and inhibited acid for TB6 was also achieved to provide suitable investigations on corrosion inhibition mechanism in 1.0 M HCl solution. The effect of concentration and temperature on the inhibiting efficiency has been examined. The thermodynamic parameters for both dissolution and adsorption processes were calculated and discussed for TB6. The adsorption of inhibitor TB6 on the mild steel surface obeys the Langmuir adsorption isotherm equation.
EFFECT OF ADDED TIP MASS ON THE NONLINEAR FLAPWISE AND CHORDWISE VIBRATION OF CANTILEVER COMPOSITE BEAM UNDER BASE EXCITATION
Authors: EFTEKHARI M. , MAHZOON M. , ZIAEI-RAD S.
Published: March 2012

In this paper, a comparative study is performed for a symmetrically laminated composite cantilever beam with and without a tip mass under harmonic base excitation. The base is subjected to both flapwise and chordwise excitations tuned to the primary resonances of the two directions and conditions of 2:1 autoparametric resonance. In the literature, the governing nonlinear equations of the same problem without tip mass have been derived using the extended Hamilton's principle. Extension is made in this study to include the effect of a tip mass on the response of the beam. The natural frequencies are obtained numerically using the diversity guided evolutionary algorithm (DGEA). Next, the multiple scales method is applied to determine the nonlinear response and stability of the system. A set of four first-order differential equations describing the modulation of the amplitudes and phases of interacting modes are derived for the perturbation analysis. For verification, the above equations are reduced to the special case of the cantilever beam without tip mass for comparison with existing results. Finally, the effect of the tip mass on the stability of the fixed points and on the amplitude of oscillation about the equilibrium points in both the frequency and force modulation responses is examined.
DIMENSION MODULES AND MODULAR LATTICES
Authors: DOMAGALSKA P. , PUCZYŁOWSKI E. R.
Published: March 2012

A module M is called a dimension module if the Goldie (uniform) dimension satisfies the formula u(A + B) + u(A ∩ B) = u(A) + u(B) for arbitrary submodules A, B of M. Dimension modules and related notions were studied by several authors. In this paper, we study them in a more general context of modular lattices with 0 to which the notion of dimension modules can be extended in an obvious way. Some constructions available in the lattice theory framework make it possible to identify several new aspects concerning the nature of dimension lattices and modules as well as to describe a number of related properties. In particular we find a lattice which can be used to test whether a given lattice or a module satisfies the studied properties. Most of the results are obtained for lattices and then they are applied to modules. However the examples are given, when possible, in the more restrictive case of modules.
THE NUMBER OF IDEMPOTENTS IN COMMUTATIVE GROUP RINGS
Authors: DANCHEV P. V.
Published: March 2012

Let R be a commutative unital ring of arbitrary characteristic and let G be a multiplicative Abelian group. For the group ring RG we completely calculate the number (finite or infinite) of its idempotents only in terms of R, G and their sections. This strengthens our previous results in Sarajevo J. Math. (2011) and Filomat (2012).
ON COREPRESENTATION OF HOPF π-COALGEBRAS
Authors: CHEN QUANGUO , WANG DINGGUO , NUERDANBIEKE BAITAKAZI
Published: March 2012

Let π be a group and H be a Hopf π-coalgebra. We investigate the criterion for the existence of a total integral of π-H-comodule algebra A in the setting of Hopf π-coalgebras, and prove that there exists a total integral θ = {θα : Hα → A} if and only if any representation of the pair (H, A) is injective in a functorial way, as a corepresentation of H, which generalizes the result invented by Doi in the ordinary Hopf algebra setting.
ON THE CLASSIFICATION OF CENTRALLY FINITE ALTERNATIVE DIVISION RINGS SATISFYING ALGEBRAIC CLOSURE CONDITIONS
Authors: GHILONI RICCARDO
Published: March 2012

In this paper, we prove that the rings of quaternions and of octonions over an arbitrary real closed field are algebraically closed in the sense of Eilenberg and Niven. As a consequence, we infer that some reasonable algebraic closure conditions, including the one of Eilenberg and Niven, are equivalent on the class of centrally finite alternative division rings. Furthermore, we classify centrally finite alternative division rings satisfying such equivalent algebraic closure conditions: up to isomorphism, they are either the algebraically closed fields or the rings of quaternions over real closed fields or the rings of octonions over real closed fields.
MAXIMUM NUMBER OF SOLUTIONS OF xq = x IN A FINITE NONCOMMUTATIVE ALGEBRA
Authors: CHINTALA VINEETH REDDY
Published: March 2012

We obtain a bound on the number of solutions of xq = x in a finite noncommutative algebra over a field with q elements. Furthermore, we completely characterize those rings for which this maximum number is attained.
SEMI-COMPLETE CROSSED MODULES OF LIE ALGEBRAS
Authors: AYTEKIN A. , CASAS J. M. , USLU E. Ö.
Published: March 2012

We investigate some sufficient and necessary conditions for (semi)-completeness of crossed modules in Lie algebras and we establish its relationships with the holomorphy of a crossed module. When we consider Lie algebras as crossed modules, then we recover the corresponding classical results for complete Lie algebras.
LIE SOLVABLE GROUP ALGEBRAS OF DERIVED LENGTH THREE IN CHARACTERISTIC THREE
Authors: CHANDRA HARISH , SAHAI MEENA
Published: March 2012

In this paper we provide a characterization of Lie solvable group algebras of derived length three over a field of characteristic three when G is a non-2-Engel group with abelian commutator subgroup.
COMMUTATIVE AUTOMORPHIC LOOPS OF ORDER p3
Authors: DE BARROS DYLENE AGDA SOUZA , GRISHKOV ALEXANDER , VOJTĚCHOVSKÝ PETR
Published: March 2012

A loop is said to be automorphic if its inner mappings are automorphisms. For a prime p, denote by [Formula: see text] the class of all 2-generated commutative automorphic loops Q possessing a central subloop Z ≅ ℤp such that Q/Z ≅ ℤp × ℤp. Upon describing the free 2-generated nilpotent class two commutative automorphic loop and the free 2-generated nilpotent class two commutative automorphic p-loop Fp in the variety of loops whose elements have order dividing p2 and whose associators have order dividing p, we show that every loop of [Formula: see text] is a quotient of Fp by a central subloop of order p3. The automorphism group of Fp induces an action of GL 2(p) on the three-dimensional subspaces of Z(Fp) ≅ (ℤp)4. The orbits of this action are in one-to-one correspondence with the isomorphism classes of loops from [Formula: see text]. We describe the orbits, and hence we classify the loops of [Formula: see text] up to isomorphism.

It is known that every commutative automorphic p-loop is nilpotent when p is odd, and that there is a unique commutative automorphic loop of order 8 with trivial center. Knowing [Formula: see text] up to isomorphism, we easily obtain a classification of commutative automorphic loops of order p3. There are precisely seven commutative automorphic loops of order p3 for every prime p, including the three abelian groups of order p3.
SYNTHESIS AND CHARACTERIZATION OF PLATE-LIKE TITANATE/COBALT BLUE PIGMENT COMPOSITES
Authors: YANG LU , LIU XIANGWEN , GOTO TAKAHIRO , YIN SHU , SATO TSUGIO
Published: March 2012

Plate-like titanate/cobalt blue pigment composite was successfully synthesized by mixing cobalt blue ( CoAl 2 O 4) pigment nanoparticles with plate-like lepidocrocite-type potassium lithium titanate ( K 0.8 Li 0.27 Ti 1.73 O 4, PLT) microparticles in water in order to improve the comfort and covering ability when applied on skin as cosmetics. PLT was synthesized by KCl flux method at 1000°C for 5 h using K 2 CO 3, Li 2 CO 3 and TiO 2 as starting materials, while CoAl 2 O 4 nanoparticle was synthesized by mixing Co ( NO 3)2 ⋅ 6 H 2 O and Al ( NO 3)3 ⋅ 9 H 2 O with the molar ratio of Co:Al 1:6 at pH 9 followed by calcination at 1000°C for 1 h. The morphology of the PLT/ CoAl 2 O 4 composite strongly depended on the solution pH. Since in a low pH solution, the surface of PLT was negatively charged, while that of cobalt blue was positively charged, CoAl 2 O 4 nanoparticles were homogenously coated on the surface of PLT by electrostatic attraction force. PLT/ CoAl 2 O 4 composites obtained showed nice feeling, high flickering pearlescent, excellent UV-shielding characteristic and novel blue color.
A SUFFICIENT CONDITION OF A POLYNOMIAL FISH POPULATION SYSTEM TO BE STABLE
Authors: LOUARTASSI YOUNES , EL MAZOUDI EL HOUSSINE , ELALAMI NOUREDDINE
Published: March 2012

In this paper, we use Lyapunov approach to study the stability of an exploited fish population system. The model considered is structured in n age classes and includes a nonlinear polynomial stock-recruitment relationship. Lyapunov candidate functions is investigated and sufficient conditions for global asymptotic stability of the studied polynomial system are proposed to allow computational implementation. The results obtained extend our previous study focusing on the solution to the same problem solved using other tools of control engineering. The advantage of the proposed approach is that the derived conditions proving the stability of the studied systems can be presented as in inequality in general and feasibility tests. The obtained results are tested by numerical examples.
New single crystal
40
Ar/
39
Ar ages improve time scale for deposition of the Omo Group, Omo–Turkana Basin, East Africa
Authors: McDougall Ian , Brown Francis H. , Vasconcelos Paulo M. , Cohen Benjamin E. , Thiede David S. , Buchanan Michael J.
Published: March 2012

Six tuffaceous beds within the Omo Group of the Omo–Turkana Basin have been dated using the
40
Ar/
39
Ar single crystal total fusion method on anorthoclase, yielding eruption ages. The Omo Group constitutes up to 800 m of subaerially exposed sediments surrounding Lake Turkana within the East African Rift system in northern Kenya and southern Ethiopia. Rhyolitic explosive eruptions produced tuffs and pumice clasts that are considered to have been deposited shortly after eruption. The new age data on feldspars from the pumice clasts range from 4.02 ± 0.04 Ma for the Naibar Tuff of the Koobi Fora Formation to 1.53 ± 0.02 Ma for Tuff K of the Shungura Formation. The Orange Tuff in the KBS Member of the Koobi Fora Formation was dated at 1.76 ± 0.03 Ma, providing good control in this part of the sequence where formerly there was a >200 ka gap. Data are consistent with earlier measurements and significantly improve age resolution within the Omo Group, which has yielded many vertebrate fossils, including hominin fossils comprising a number of species. We suggest new age estimates for a limited number of hominin specimens.

Supplementary material:

Eleven tables and nine figures are available at
www.geolsoc.org.uk/SUP18506
.
Lateral versus vertical emplacement in shallow-level intrusions? The Slieve Gullion Ring-complex revisited
Authors: Emeleus C. Henry , Troll Valentin R. , Chew David M. , Meade Fiona C.
Published: March 2012

Recent studies on shallow-level arcuate intrusions have identified numerous examples of horizontal mineral fabrics. These are commonly interpreted as reflecting considerable lateral flow during magma emplacement, thus querying established ‘semi-vertical’ ring-dyke models. We question the recent lateral emplacement model proposed for the Palaeocene Slieve Gullion Ring-complex, NE Ireland, where the absence of steep fabrics in parts of the ring-complex has been used to support a shallow, semi-horizontal sheet intrusion mechanism. We argue that such simple flow models cannot be applied to explosive ring-fissure eruptions and that fabric data alone do not warrant rejection of the ring-dyke model. Moreover, the apparent ‘absence of steep intrusive contacts’ along the intrusion’s perimeter is readdressed and we present numerous examples of outcrops (27) with steep-sided geometries. The Camlough Breccias are reinterpreted as the product of gas-driven tuffisites injected along the active ring-fault (rather than of purely tectonic origin). Crucially, the porphyritic microgranite and porphyritic rhyolite ring-dyke rocks exhibit geochemical and petrographic signatures of contamination by the geographically restricted Palaeozoic Newry granodiorite and are best explained through crustal interaction vertically beneath the ring-complex. Subsequently, these silicic magmas rose into ignimbrite feeders along a caldera ring-fault system that was emplaced into near-surface vent-filling breccias.
Sill morphology and comparison of brittle and non-brittle emplacement mechanisms
Authors: Schofield Nick J. , Brown David J. , Magee Craig , Stevenson Carl T.
Published: March 2012

Magmatic sheet intrusions contribute significantly to the upper crustal magma transport network. The emplacement mechanism of the magmatic sheets controls the final geometry of the intrusions and the characteristics of host rock deformation. Previous observations have highlighted the preponderance of brittle structures, associated with shallow-level sheet intrusions. However, recent studies have suggested that non-brittle host rock behaviour also occurs, particularly related to the formation of magma fingers during shallow-level sill intrusion. Here, we examine both brittle and non-brittle intrusion mechanisms and expand upon them with field observations from a series of widespread and variable magmatic systems. Non-brittle emplacement appears primarily associated with viscous flow of the host rock during intrusion and is therefore intimately linked to the contemporaneous host rock rheology as well as magma dynamics. Purely brittle and non-brittle emplacement processes are found to be end members with many intrusions containing evidence of both behaviours. Deriving the host rock characteristics is therefore important for discerning potential diagnostic intrusion indicators and intrusion geometries both within the field and in modelling. Incorporation of variable host material behaviours in numerical and analogue modelling, tuned using direct field observations, may consequently further our understanding of the controls on shallow-level intrusion.
Major early thrusting as a control on the Palaeoproterozoic evolution of the Lewisian Complex: evidence from the Outer Hebrides, NW Scotland
Authors: Mason Andrew J.
Published: March 2012

New structural, metamorphic and geochronological data suggest that the Lewisian Complex of the Outer Hebrides can be interpreted as a Proterozoic orogen in which a thrust sheet of juvenile arc material was driven over Archaean gneisses at an early stage. Incubation and loading of the underlying Archaean gneisses triggered prograde metamorphism and extensive ductile deformation with a strong gravitational flattening component combined with top-to-the-WNW transport. Large shear zones developed at this time are of local importance, but are not fundamental structural boundaries. The recognition of early orogenic thrusting followed by extensive ductile deformation shows a close resemblance to the sequence of events recognized within the Nagssugtoqidian orogen, with which the Lewisian Complex is correlated. As in the Nagssugtoqidian orogen, younger penetrative ductile deformation often masks the major structural boundaries formed by older thrusts.

Supplementary material:

Detailed structural and lithological maps of the Langavat Belt, and geochronological data and analytical methods description are available at
www.geolsoc.org.uk/SUP18515
.
Mid-Eocene renewal of magmatism in NW Scotland: the Loch Roag Dyke, Outer Hebrides
Authors: Faithfull J. W. , Timmerman M. J. , Upton B. G. J. , Rumsey M. S.
Published: March 2012

A monchquite dyke, in the vicinity of Loch Roag, Lewis, Outer Hebrides has an unusually enriched chemistry, and contains a unique assemblage of megacrysts and xenoliths from the lithosphere of the Hebridean craton. A
40
Ar/
39
Ar plateau age of 45.2 ± 0.2 Ma (2σ) of a phlogopite megacryst from the dyke overlaps an earlier reported K–Ar age, and confirms that the British Palaeogene Igneous Province extended into the Eocene. Similar late low-volume melts were erupted in the Eocene and Oligocene in West and East Greenland, suggesting that such late-stage magmatic rejuvenescence is a widespread feature across the North Atlantic Igneous Province.
Chronic nicotine induces hypoxia inducible factor-2α in perinatal rat adrenal chromaffin cells: role in transcriptional upregulation of KATP channel subunit Kir6.2
Authors: Salman Shaima , Brown Stephen T. , Nurse Colin A.
Published: March 2012

Fetal nicotine exposure causes impaired adrenal catecholamine secretion and increased neonatal mortality during acute hypoxic challenges. Both effects are attributable to upregulation of ATP-sensitive K+ channels (KATP channels) and can be rescued by pretreatment with the blocker, glibenclamide. Although use of in vitro models of primary and immortalized, fetal-derived rat adrenomedullary chromaffin cells (i.e., MAH cells) demonstrated the involvement of α7 nicotinic ACh receptor (nAChR) stimulation and the transcription factor, HIF-2α, the latter's role was unclear. Using Western blots, we show that chronic nicotine causes a progressive, time-dependent induction of HIF-2α in MAH cells that parallels the upregulation of KATP channel subunit, Kir6.2. Moreover, a common HIF target, VEGF mRNA, was also upregulated after chronic nicotine. All the above effects were prevented during co-incubation with α-bungarotoxin (100 nM), a specific α7 nAChR blocker, and were absent in HIF-2α-deficient MAH cells. Chromatin immunoprecipitation (ChIP) assays demonstrated binding of HIF-2α to a putative hypoxia response element in Kir6.2 gene promoter. Specificity of this signaling pathway was validated in adrenal glands from pups born to dams exposed to nicotine throughout gestation; the upregulation of both HIF-2α and Kir6.2 was confined to medullary, but not cortical, tissue. This study has uncovered a signaling pathway whereby a nonhypoxic stimulus (nicotine) promotes HIF-2α-mediated transcriptional upregulation of a novel target, Kir6.2 subunit. The data suggest that the HIF pathway may be involved in KATP channel-mediated neuroprotection during brain ischemia, and in the effects of chronic nicotine on ubiquitous brain α7 nAChR.
Functional Cftr in crypt epithelium of organotypic enteroid cultures from murine small intestine
Authors: Liu Jinghua , Walker Nancy M. , Cook Matthew T. , Ootani Akifumi , Clarke Lane L.
Published: March 2012

Physiological studies of intact crypt epithelium have been limited by problems of accessibility in vivo and dedifferentiation in standard primary culture. Investigations of murine intestinal stem cells have recently yielded a primary intestinal culture in three-dimensional gel suspension that recapitulates crypt structure and epithelial differentiation (Sato T, Vries RG, Snippert HJ, van de Wetering M, Barker N, Stange DE, Van Es JH, Abo A, Kujala P, Peters PJ, Clevers H. Nature 459: 262–265, 2009). We investigated the utility of murine intestinal crypt cultures (termed “enteroids”) for physiological studies of crypt epithelium by focusing on the transport activity of the cystic fibrosis transmembrane conductance regulator Cftr. Enteroids had multiple crypts with well-differentiated goblet and Paneth cells that degranulated on exposure to the muscarinic agonist carbachol. Modified growth medium provided a crypt proliferation rate, as measured by 5-ethynyl-2′-deoxyuridine labeling, which was similar to proliferation in vivo. Immunoblots demonstrated equivalent Cftr expression in comparisons of freshly isolated crypts with primary and passage 1 enteroids. Apparent enteroid differences in mRNA expression of other transporters were primarily associated with villous epithelial contamination of freshly isolated crypts. Microelectrode analysis revealed cAMP-stimulated membrane depolarization in enteroid epithelium from wild-type (WT) but not Cftr knockout (KO) mice. Morphological and microfluorimetric studies, respectively, demonstrated Cftr-dependent cell shrinkage and lower intracellular pH in WT enteroid epithelium in contrast to Cftr KO epithelium or WT epithelium treated with Cftr inhibitor 172. We conclude that crypt epithelium of murine enteroids exhibit Cftr expression and activity that recapitulates crypt epithelium in vivo. Enteroids provide a primary culture model that is suitable for physiological studies of regenerating crypt epithelium.
Mechanical loading induces the expression of a Pol I regulon at the onset of skeletal muscle hypertrophy
Authors: von Walden Ferdinand , Casagrande Vandre , Östlund Farrants Ann-Kristin , Nader Gustavo A.
Published: March 2012

The main goal of the present study was to investigate the regulation of ribosomal DNA (rDNA) gene transcription at the onset of skeletal muscle hypertrophy. Mice were subjected to functional overload of the plantaris by bilateral removal of the synergist muscles. Mechanical loading resulted in muscle hypertrophy with an increase in rRNA content. rDNA transcription, as determined by 45S pre-rRNA abundance, paralleled the increase in rRNA content and was consistent with the onset of the hypertrophic response. Increased transcription and protein expression of c-Myc and its downstream polymerase I (Pol I) regulon (POL1RB, TIF-1A, PAF53, TTF1, TAF1C) was also consistent with the increase in rRNA. Similarly, factors involved in rDNA transcription, such as the upstream binding factor and the Williams syndrome transcription factor, were induced by mechanical loading in a corresponding temporal fashion. Chromatin immunoprecipitation revealed that these factors, together with Pol I, were enriched at the rDNA promoter. This, in addition to an increase in histone H3 lysine 9 acetylation, demonstrates that mechanical loading regulates rRNA synthesis by inducing a gene expression program consisting of a Pol I regulon, together with accessory factors involved in transcription and chromatin remodeling at the rDNA promoter. Altogether, these data indicate that transcriptional and epigenetic mechanisms take place in the regulation of ribosome production at the onset of muscle hypertrophy.
Hypoxia activates nucleus tractus solitarii neurons projecting to the paraventricular nucleus of the hypothalamus
Authors: King T. Luise , Heesch Cheryl M. , Clark Catharine G. , Kline David D. , Hasser Eileen M.
Published: March 2012

Peripheral chemoreceptor afferent information is sent to the nucleus tractus solitarii (nTS), integrated, and relayed to other brain regions to alter cardiorespiratory function. The nTS projects to the hypothalamic paraventricular nucleus (PVN), but activation and phenotype of these projections during chemoreflex stimulation is unknown. We hypothesized that activation of PVN-projecting nTS neurons occurs primarily at high intensities of hypoxia. We assessed ventilation and cardiovascular parameters in response to increasing severities of hypoxia. Retrograde tracers were used to label nTS PVN-projecting neurons and, in some rats, rostral ventrolateral medulla (RVLM)-projecting neurons. Immunohistochemistry was performed to identify nTS cells that were activated (Fos-immunoreactive, Fos-IR), catecholaminergic, and GABAergic following hypoxia. Conscious rats underwent 3 h normoxia ( n = 4, 21% O2) or acute hypoxia (12, 10, or 8% O2; n = 5 each). Hypoxia increased ventilation and the number of Fos-IR nTS cells (21%, 13 ± 2; 12%, 58 ± 4; 10%, 166 ± 22; 8%, 186 ± 6). Fos expression after 10% O2was similar whether arterial pressure was allowed to decrease (−13 ± 1 mmHg) or was held constant. The percentage of PVN-projecting cells activated was intensity dependent, but contrary to our hypothesis, PVN-projecting nTS cells exhibiting Fos-IR were found at all hypoxic intensities. Notably, at all intensities of hypoxia, ∼75% of the activated PVN-projecting nTS neurons were catecholaminergic. Compared with RVLM-projecting cells, a greater percentage of PVN-projecting nTS cells was activated by 10% O2. Data suggest that increasing hypoxic intensity activates nTS PVN-projecting cells, especially catecholaminergic, PVN-projecting neurons. The nTS to PVN catecholaminergic pathway may be critical even at lower levels of chemoreflex activation and more important to cardiorespiratory responses than previously considered.
Dynamics of spatial frequency tuning in mouse visual cortex
Authors: Vreysen Samme , Zhang Bin , Chino Yuzo M. , Arckens Lutgarde , Van den Bergh Gert
Published: March 2012

Neuronal spatial frequency tuning in primary visual cortex (V1) substantially changes over time. In both primates and cats, a shift of the neuron's preferred spatial frequency has been observed from low frequencies early in the response to higher frequencies later in the response. In most cases, this shift is accompanied by a decreased tuning bandwidth. Recently, the mouse has gained attention as a suitable animal model to study the basic mechanisms of visual information processing, demonstrating similarities in basic neuronal response properties between rodents and highly visual mammals. Here we report the results of extracellular single-unit recordings in the anesthetized mouse where we analyzed the dynamics of spatial frequency tuning in V1 and the lateromedial area LM within the lateral extrastriate area V2L. We used a reverse-correlation technique to demonstrate that, as in monkeys and cats, the preferred spatial frequency of mouse V1 neurons shifted from low to higher frequencies later in the response. However, this was not correlated with a clear selectivity increase or enhanced suppression of responses to low spatial frequencies. These results suggest that the neuronal connections responsible for the temporal shift in spatial frequency tuning may considerably differ between mice and monkeys.
Synapse maturation is enhanced in the binocular region of the retinocollicular map prior to eye opening
Authors: Furman Moran , Crair Michael C.
Published: March 2012

In the developing visual system of mammals, retinal axons from the two eyes compete for postsynaptic partners. After eye opening, this process is regulated in part by homeostatically constrained competition for synaptic connectivity with target neurons. However, prior to eye opening, the functional and synaptic basis of binocular map development is unclear. To examine the role of binocular interactions during early stages of visual map development, we performed in vitro patch-clamp recordings from the superior colliculus (SC) of neonatal mice. Using newly designed slice preparations, we compared retinocollicular synapse development in the medial SC, which receives binocular input, and the lateral SC, which is predominantly monocular. Surprisingly, we found that at P6–7, when eye-specific segregation has just emerged, retinocollicular synapses were stronger and more mature and dendritic arbors were more elaborate in the medial than the lateral SC. Furthermore, monocular enucleation of the ipsilateral eye at P0 selectively reduced synaptic strength and dendritic branching in the medial SC and abolished the differences normally observed between the two slices at P6–7. This specifically implicates binocular interactions in the development of retinocollicular connectivity prior to eye opening. Our findings contrast with the predictions of a constrained-connectivity model of binocular map development and suggest instead that binocular competition prior to eye opening enhances retinocollicular synaptic strength and the morphological development of retino-recipient neurons.