bluuebunny/crossref_metadata_2025 huggingface dataset:
Honeybee colony collapse due to Nosema ceranae in professional apiaries
Authors: Higes Mariano , Martín‐Hernández Raquel , Garrido‐Bailón Encarna , González‐Porto Amelia V. , García‐Palencia Pilar , Meana Aranzazu , Del Nozal María J. , Mayo R. , Bernal José L.
Published: February 2009

Honeybee colony collapse is a sanitary and ecological worldwide problem. The features of this syndrome are an unexplained disappearance of adult bees, a lack of brood attention, reduced colony strength, and heavy winter mortality without any previous evident pathological disturbances. To date there has not been a consensus about its origins. This report describes the clinical features of two professional bee‐keepers affecting by this syndrome. Anamnesis, clinical examination and analyses support that the depopulation in both cases was due to the infection by Nosema ceranae (Microsporidia), an emerging pathogen of Apis mellifera. No other significant pathogens or pesticides (neonicotinoids) were detected and the bees had not been foraging in corn or sunflower crops. The treatment with fumagillin avoided the loss of surviving weak colonies. This is the first case report of honeybee colony collapse due to N. ceranae in professional apiaries in field conditions reported worldwide.
Reporting ethical matters in The Journal of Physiology: standards and advice
Authors: Drummond Gordon B.
Published: February 2009

Reporting of ethical matters in The Journal is very important. To advise and assist authors, particularly those who may be less familiar with the legislation in the UK, this article sets out the basic principles and methods that should be used and provides many key web sources of information. It addresses the structure of regulations, and introduces the concept of research governance. The UK law is summarized. Advice is given on the format and description of experiments, and common problems addressed. Aspects of human studies are addressed. Ethical considerations of publication such as authorship and originality, and problems such as plagiarism and fabrication are described. Updates will be published regularly.
Gas-phase structure and relative stability of proton-bound homo- and heterochiral clusters of tetra-amide macrocycles with amines
Authors: Fraschetti Caterina , Pierini Marco , Villani Claudio , Gasparrini Francesco , Filippi Antonello , Speranza Maurizio
Published: February 2009

The structure, stability, and CID pattern of proton-bound homochiral and heterochiral complexes, formed in the gas phase by the combination of two molecules of a chiral macrocyclic tetra-amide and an amine B, i.e. CH3NH2, (CH3)2NH, or (S)-(–)-1-phenylethylamine, have been examined by ESI-ITMS-CID mass spectrometry. With B = CH3NH2, the CID pattern is characterized by the predominant loss of B, accompanied by a much less extensive release of one tetra-amide molecule. With (S)-(–)-1-phenylethylamine, loss of a tetra-amide molecule efficiently competes with loss of B. Finally, with (CH3)2NH, loss of a tetra-amide molecule predominates over loss of B. No appreciable isotope and chiral guest configuration effects have been detected in the fragmentation of the homochiral complexes. A distinct configurational effect has been appreciated in the CID of the homo- and the heterochiral complexes with all amines used. The results of this study have been discussed in the light of semi-empirical computational evidence. The differences in the CID patterns of the homo- and the heterochiral complexes have been rationalized in terms of structural factors and of the basicity of amine B.
Gaseous Ni+ complexes with BINOL derivatives and chiral esters in the gas phase: an experimental and theoretical investigation
Authors: Novara Francesca R. , Zhang Xinhao , Schröder Detlef , Schwarz Helmut
Published: February 2009

The gas-phase behavior of monocationic Ni(II) complexes that contain as building blocks optically pure BINOL derivatives and two chiral hydroxy esters is investigated by means of electrospray ionization (ESI) mass spectrometry. Upon collision-induced dissociation (CID), the complexes containing ethyl 2-hydroxypropionate (ethyl lactate) only lose the ester ligand. The complexes bearing ethyl 3-hydroxybutyrate instead either lose the ester ligands or undergo bond activation followed by elimination of the corresponding β-ketoester (ethyl acetylacetate) as revealed by deuterium labeling. Comparison of the results obtained for com- plexes with different chiralities reveals the operation of a significant stereochemical effect (SE) in the gas-phase dehydrogenation of ethyl 3-hydroxybutyrate by gaseous [(BINOLato)Ni]+ ions. Instead, no substantial differences in the CID patterns for the complexes bearing the ester-substituted BINOL derivative are found. The results provide insights into the gas-phase coordination of metal cations by BINOL derivatives and into the molecular features, which are responsible for gas-phase enantioselective processes. Additional mechanistic aspects are disclosed by exploratory calculations employing density functional theory using the B3LYP method.
Preferential formation of homochiral silver(I) complexes upon coordination of two aza[6]helicene ligands to Ag+ ions
Authors: Míšek Jiří , Tichý Miloš , Stará Irena G. , Starý Ivo , Schröder Detlef
Published: February 2009

By means of selective deuterium labeling of 1-aza[6]helicene combined with resolution of the enantiomers, chiral discrimination in silver(I)-bound dimers of the type [LAgL′]+ is probed by electrospray mass spectrometry. The analysis of the results reveals a pronounced preference for the formation of homochiral dimers (P,P and M,M, respectively) over the statistically preferred heterochiral variant (P,M), which is fully consistent with previous data about the formation of homochiral dimers in the condensed phase. Further, competitive experiments with mixtures of 1- and 2-aza[6]helicene suggest a largely preferred coordination of 1-aza[6]helicene to the silver(I) cation.
Diastereoisomeric proton-bound complexes of 1,5-diaza-cis-decalin in the gas phase
Authors: Roithová Jana
Published: February 2009

Diastereoisomeric proton-bound complexes of 1,5-diaza-cis-decalin (1) with butan-2-amine (2) are studied by means of the DFT calculations and mass spectrometry. The calculations reveal that 2 is bound via proton to only one nitrogen atom of the bicyclic base 1. The homochiral complex is favored by about 4 kJ/mol over the heterochiral complex. For a more loosely bound ion-pair complex [(1H)I(2H)]+ of the protonated bases 1 and 2 with an iodine counterion the energy difference drops to about 2 kJ/mol. Chiral effects in the formation of [(1)H(2)]+ are studied by the collision-induced dissociation of [(1H)I(2H)]+ generated by the electrospray ionization of the solution of [1·Cu(OH)I] and 2 in acetonitrile. The dominant fragmentation of [(1H)I(2H)]+ leads to 1·H+ and 2·HI, which is at small collision energies accompanied by the elimination of HI leading to the desired [(1)H(2)]+ ion. The chiral effect of 1.2 is determined in favor for the formation of the homochiral complex [(1)H(2)]+.
ANALYTICAL CHARACTERIZATION AND MODELING OF SHIELDED TEST STRUCTURES FOR RF-CMOS
Authors: TORRES-RIOS EMMANUEL , TORRES-TORRES REYDEZEL , MURPHY-ARTEAGA ROBERTO , GUTIÉRREZ-D EDMUNDO A.
Published: February 2009

A new modeling and parameter extraction methodology to represent the parasitic effects associated with shielded test structures is presented in this paper. This methodology allows to accurately account for the undesired effects introduced by the test fixture when measuring on-wafer devices at high frequencies. Since the proposed models are based on the physical effects associated with the structure, the obtained parameters allow the identification of the most important parasitic components, which lead to potential measurement uncertainty when characterizing high-frequency devices. The proposed methodology is applied to structures fabricated on different metal levels in order to point out the advantages and disadvantages in each case. The validity of the modeling and characterization methodology is verified by achieving excellent agreement between simulations and experimental data up to 50 GHz.
GERMANIUM ON SAPPHIRE
Authors: GAMBLE H.S. , BAINE P.T. , WADSWORTH H. , LOW Y.H. , RAINEY P.V. , RUDDELL F.H. , ARMSTRONG B.M. , McNEILL D.W. , MITCHELL S.J.N.
Published: February 2009

This paper explores the potential of germanium on sapphire (GeOS) wafers as a universal substrate for System on a Chip (SOC), mm wave integrated circuits (MMICs) and optical imagers. Ge has a lattice constant close to that of GaAs enabling epitaxial growth. Ge , GaAs and sapphire have relatively close temperature coefficients of expansion (TCE), enabling them to be combined without stress problems. Sapphire is transparent over the range 0.17 to 5.5 μm and has a very low loss tangent (α) for frequencies up to 72 GHz. Ge bonding to sapphire substrates has been investigated with regard to micro-voids and electrical quality of the Ge back interface. The advantages of a sapphire substrate for integrated inductors, coplanar waveguides and crosstalk suppression are also highlighted. MOS transistors have been fabricated on GeOS substrates, produced by the Smart-cut process, to illustrate the compatibility of the substrate with device processing.
SINGLE EVENT EFFECTS IN THE NANO ERA
Authors: ALLES M. L. , MASSENGILL L. W. , SCHRIMPF R. D. , WELLER R. A. , GALLOWAY K. F.
Published: February 2009

Scaling of complementary metal oxide semiconductor (CMOS) technologies to the sub-100 nm dimension regime increase the sensitivity to pervasive terrestrial radiation. Diminishing levels of charge associated with information in electronic circuits, interactions of multiple transistors due to tight packing densities, and high circuit clock speeds make single event effects (SEE) a reliability consideration for advanced electronics. The trend to adapt and apply commercial IC processes for space and defense applications has provided a catalyst to the development of infrastructure for analysis and mitigation that can be leveraged for advanced commercial electronic devices. In particular, modeling and simulation, leveraging the dramatic reduction in computing cost and increase in computing power, can be used to analyze the response of electronics to radiation, to develop and evaluate mitigation approaches, and to calculate the frequency of problematic events for target applications and environments.
NANOCOMPONENTS: A DESIGNER'S POINT OF VIEW
Authors: FANET HERVÉ
Published: February 2009

This paper gives a system designer's point of view regarding the emergence of the many new devices that are being considered as possible replacement of the Metal Oxyde Semiconductor Field effect transistor. The first part is a tentative to define criteria for the systemability of nanodevices. The second part is a short overview of the evolution of information processing systems. The third part is a more specific study of the demultiplexing and fault tolerance problems.
SILICON SPINTRONICS
Authors: APPELBAUM IAN
Published: February 2009

Recent advances in successful operation of silicon-based devices where transport is dependent on electron magnetic moment, or "spin", could provide a future alternative to CMOS for logic processing. The basics of this spin electronics (Spintronics) technology are discussed and the specific methods necessary for application to silicon are described. Fundamental measurements of spin polarization and spin precession are demonstrated.
NANO CHARACTERIZATION OF MATERIALS
Authors: SCHRODER DIETER K.
Published: February 2009

Material characterization is challenged by continuously decreasing device dimensions placing significant demands on characterization instruments and measurement interpretation. Numerous techniques exist and a few are highlighted here. Some of these have existed for a long time, while others have only emerged from the laboratory recently. Generally they are more user-friendly and have reasonable turn-around times. The trend in many techniques is clearly toward characterization of smaller dimensions. Among the myriad of characterization techniques in use today, I will discuss recent advances in transmission electron microscopy (TEM), electron holography, magnetic exchange force microscopy (MExFM), atom probe ion field ion microscopy, and X-ray tomography. They have made significant advances in the last few years and in some cases have produced very impressive results. For example, TEM is now able to generate images with 0.05 nm resolution, allowing display of individual atoms. MExFM in conjunction with magnetic fields has demonstrated vertical resolution of 0.0015 nm. Helium ion microscopy is also highlighted because it contributes a new application of ion beams, which had been largely the domain of Rutherford backscattering. Progress in developing further advances in nm dimensional characterization will, no doubt, continue to satisfy the demand for such measurements in the future.
LARGE AREA NANOSCALE PATTERNING BY INTERFEROMETRIC LITHOGRAPHY – NANOPHOTONICS AND NANOFLUIDICS
Authors: BRUECK S. R. J.
Published: February 2009

Interferometric lithography offers a facile, inexpensive, large-area fabrication capability for the formation of large areas of nanoscale periodic features. A self-aligned frequency doubling process to a 22-nm half-pitch is demonstrated. Many investigations of nanoscale phenomena require large-area samples, both for scientific investigations and certainly for ultimate large-scale applications. The utility of interferometric lithography is demonstrated to applications in nanophotonics and nanofluidics. For nanophotonics, metamaterial fabrication, negative index metamaterials and plasmonic applications are discussed. Two approaches to the fabrication of nanofluidic structures: etching and oxidation of silicon substrates, and colloidal deposition of silica nanoparticles to form porous walls and roofs followed by calcination to remove the photoresist and sinter the particles. These later structures have evident biomimetic functionality.
CYCLOTRON RESONANCE VANISHING EFFECT AND THz DETECTION
Authors: CHEBOTAREV ANDREY , CHEBOTAREVA GALINA
Published: February 2009

Experimental measurements of photoresistivity under terahertz (THz) radiation in low magnetic fields at conditions of cyclotron resonance (CR) in two-dimensional electron system (2DES) of GaAs / AlGaAs nanostructures are presented and discussed. We report the experimental discovery of "CR-vanishing effect" (CRV) in GaAs / AlGaAs heterostructures with high mobility as a well-defined gap on CR-line that is independent on incident THz power. Our analysis shows that the CRV may appear in systems with well correlated state of 2D electrons such as plasma waves and others. Fundamental nature of these correlated states of electrons in 2DES is discussed. Future THz detectors utilizing the new correlated states in 2DES may expand horizons for supersensitive detection in sub-THz and THz frequencies ranges.
TERAHERTZ QUANTUM CASCADE LASERS AND REAL-TIME T-RAYS IMAGING AT VIDEO RATE
Authors: HU Q.
Published: February 2009

We report our development of terahertz (THz) quantum-cascade lasers with record performance. Using those high-power lasers as the illumination sources and a focal-plane array camera, we are able to perform real-time THz imaging at video rate.
PROPOSAL OF NOVEL STRUCTURE LIGHT EMITTING DEVICES CONSISTING OF InN/GaN MQWs WITH ULTRATHIN InN WELLS IN GaN MATRIX
Authors: YOSHIKAWA AKIHIKO , CHE SONG-BEK
Published: February 2009

Novel structure light emitting diodes (LEDs) made of InN / GaN multiple quantum wells (MQWs) are proposed and demonstrated. The MQWs consisted of very fine and narrow 1 monolayer (ML)-thick InN wells embedded in GaN matrix, which were successfully fabricated by radio-frequency molecular beam epitaxy. The thickness of InN wells can be fractional ML and/or two MLs depending on the growth conditions, resulting in different wavelength light emissions from deep violet to blue. Epitaxy processes for the MQWs fabrication are very unique on the basis of the self-ordering and coherent growth mode for atomically flat ~1 ML InN well deposition on GaN template. It is shown that the epitaxy temperature for 1 ML InN wells can be much higher than the highest epitaxy temperature of thick InN layer due to the effects of GaN matrix. Bright electroluminescence (EL) emission is observed at 418 nm at room temperature in LEDs fabricated by the MQWs. Further it is confirmed that the quantum confined Stark effect (QCSE) in InN wells is remarkably reduced due to the effects with using ultimately thin InN wells as active layers, resulting an extremely small blue shift in the EL peak wavelengths for two orders different injection current levels.
RECENT DEVELOPMENTS IN BROADBAND TERAHERTZ SPECTROSCOPY
Authors: KARPOWICZ NICHOLAS , DAI JIANMING , ZHANG X.-C. , ZHANG LIANGLIANG , ZHANG CUNLIN
Published: February 2009

Terahertz time-domain measurements using air as the emission and detection medium are shown to enable broadband spectroscopy with continuous coverage of the entire terahertz band, from 0.1 to over 10 THz. It is shown that the unique properties of using a gaseous medium allow for excellent phase matching without interruptions from crystalline phonon modes or antenna resonant structures from conventional solid state emitters and sensors, allowing the full bandwidth of the laser pulse to be used. It is also shown that the limiting factor on the system bandwidth is the temporal profile of the probe pulse used for detection, and how modification of this profile can further enhance the detection bandwidth.
CMOS EIGHT-TRANSISTOR MEMORY CELL FOR LOW-DYNAMIC-POWER HIGH-SPEED EMBEDDED SRAM
Authors: ABDEL-HAFEEZ SALEH M. , MATALKAH ANAS S.
Published: February 2009

Embedded SRAM design with high noise margin between read and write, low power, low supply voltages, and high speed become essential features in VLSI embedded applications. The complete embedded SRAM design of self-timing synchronization is proposed based on the CMOS eight-transistor (8T-Cell) memory cell circuit. The cell is based on the traditional six-transistor (6T-Cell) cross-coupled invertors with the addition of two NMOS transistors for separate read buffer circuit. The read buffer structure is based on pre-charging the read bit-line during the low value of read clock and evaluating the read bit-line during the high value of read clock, thereby maintaining one active line per column and eliminating the use of traditional sense amplifier with all its synchronization schemes. The simulation results show that the embedded SRAM of size 128-bit × 128-bit is operating at a maximum frequency of 200 MHz for Write and Read clock cycles with 1.62 V power supply, and measures a total average power consumption of 22.60 mW. All simulation results were conducted on 0.18 μm TSMC single poly and three layers of metals measuring a cell area of 2.2 × 3.0 μ m 2. The circuit is not meant to replace the SRAM with 6T-Cell transistor structure; however, it is attractive for applications related to high density with automation road-map design, such as graphic and network processor chips. In these applications, memory sizes are introduced in many different irregular geometries and uses all over the chip with storage sizes less than 20 k-bit, in addition, it is susceptible to large substrate noise as well as large coupling wire routing.
MULTI-FREQUENCY APPROACH TO FAULT DICTIONARY OF LINEAR ANALOG FAULT DIAGNOSIS
Authors: SARAT CHANDRA BABU N. , PRASAD V. C. , VENU MADHAVA RAO S. P. , LAL KISHORE K.
Published: February 2009

An efficient method to eliminate redundant frequencies present in one of the existing multi-frequency methods for analog fault diagnosis is proposed in this paper. First the two-dimensional fault dictionary is constructed where entries are gain signatures of all faults and frequencies. The faults belonging to the same quantization levels are numbered sequentially and a frequency that has an ambiguity set with the highest number faults is eliminated after verifying that there are no repetitions after the deletion of this frequency. In this manner, all frequencies are examined for deletion. Finally the test frequencies, which cannot be deleted, remain resulting in a minimal set of test frequencies of a network to isolate a given set of faults.

Another method proposes a technique, which generates more number of frequencies to isolate all the faults, if the test frequencies generated using the existing methods are not sufficient.
DYNAMIC VOLTAGE SCALING CONTINUOUS ADAPTIVE-SIZE CELL DESIGN TECHNIQUE
Authors: KIROLOS SAMI , MASSOUD YEHIA
Published: February 2009

In this paper, we present an adaptive circuit design that is capable of increasing the effective size-ratio of combinational logic gates to extend the balanced operation in the subthreshold region as well as to maintain high performance at the nominal VDD. We optimize the sizes of the PMOS transistors in the pull-up network for minimum power dissipation and propagation delay over a wide range of supply voltage. In addition to the minimized energy operation, the dynamically adjustable gate size-ratio allows the gate to preserve a symmetric voltage transfer characteristic at both normal supply and subthreshold operation, which translates to maximized noise margins. Simulation results show that up to 70.9% reduction in the energy can be achieved for a ring oscillator, as compared to the fixed size design capable of operating under supply voltage in the range of 75 mV to 1.2 V. For designs working under dynamic voltage scaling schemes, our technique presents a very effective and efficient solution for balanced minimum energy operation in the subthreshold region while preserving high performance at the nominal supply voltage.
AN ELECTRONICALLY TUNABLE OSCILLATOR USING A SINGLE ACTIVE DEVICE AND TWO CAPACITORS
Authors: KOKSAL M. , SAGBAS M. , SEDEF H.
Published: February 2009

A novel resistorless oscillator is presented. The proposed structure enjoys electronic tunability property with minimum number of active and passive components. This oscillator uses a current-mode (CM) active device and has properties of current mode circuits. The validity of the proposed circuit is verified by experimental results.
A NEW GENETIC DESIGN FOR ERROR CORRECTING CODE FOR POWER MINIMIZATION
Authors: LEE HEESUNG , KIM EUNTAI
Published: February 2009

Error correcting codes (ECCs) are commonly used as a protection against the soft errors. Single error correcting and double error detecting (SEC–DED) codes are generally used for this purpose. Such circuits are widely used in industry in all types of memory, including caches and embedded memory. In this paper, a new genetic design for ECC is proposed to perform SEC–DED in the memory check circuit. The design is aimed at finding the implementation of ECC which consumes minimal power. We formulate the ECC design into a permutable optimization problem and employ special genetic operators appropriate for this formulation. Experiments are performed to demonstrate the performance of the proposed method.
NEW MULTIPLE FRAME MOTION COMPENSATED INTERPOLATION ALGORITHM FOR FRAME RATE UP-CONVERSION
Authors: XUE ZHUO , LOO KOK-KEONG , COSMAS JOHN , YIP PIK-YEE
Published: February 2009

In this paper, a new frame rate up-conversion (FRC) using Backward Multiple Reference Frame Motion (BMRF) compensated interpolation (MCI) algorithm is proposed. The BMRF algorithm has been compared with two most common MCI methods, Temporal Linear (TLIN) and Bidirectional MCI (BID) used in FRC, in the aspect of PSNR, perceptual quality, and computational complexity. The simulation results clearly showed that BMRF presented a trade-off solution between computation and interpolation quality. By using simple weighted frame interpolation between multiple frames, it reduced computation rapidly while keeping similar interpolation quality when compared to the BID method. The simplicity of the BMRF algorithm made it suitable for either software or hardware implementation essential for real-time FRC applications.
AR LATTICE ℓ-STEP AHEAD OUTPUT UNCERTAINTY PREDICTION SCHEME WITH UNCERTAINTY INTERVALS
Authors: NIKOLAKOPOULOS GEORGE , TZES ANTHONY
Published: February 2009

In this paper, a lattice ℓ-step ahead output uncertainty prediction algorithm is presented. The proposed prediction scheme is applicable to linear, stable, auto-regressive (AR) systems. The uncertainty predictors utilize the structure of the lattice filters. Subject to the saturation limits of the excitation signal, the measurement of the system output, and the a priori bounds of the reflection coefficients, the set of the feasible predicted output variables is computed. The suggested scheme is recursively computed over an ℓ-step ahead future time window, while the prediction uncertainty intervals are similarly computed over the lattice stages, regarding the forward and the backward prediction errors. Simulation results are presented that prove the efficacy of the employed lattice uncertainty predictors.
HISTORY AND PROGRESS OF THE TOW–THOMAS BIQUADRATIC FILTER PART II: OTRA, CCII, AND DVCC REALIZATIONS
Authors: SOLIMAN AHMED M.
Published: February 2009

The realization of the Tow–Thomas (TT) circuit using the Operational Transresistance Amplifier (OTRA) is reviewed. The circuit employs two OTRA, and all passive elements are floating as the original Tow–Thomas circuit. The Current Conveyor (CCII) TT circuits are reviewed next. The progress in the realization of the TT circuit using CCII is demonstrated clearly by summarizing eight different circuits. One of the circuits has the advantage of very high input impedance using all grounded resistors and capacitors. The Differential Voltage Current Conveyor (DVCC) as the active building block in realizing the TT circuit is also considered. Finally, current mode TT circuits using balanced output CCII are summarized. Top Spice (level 49), simulation results using technology SCN 05 feature size 0.5 μm from MOSIS vendor: AGILENT are included to demonstrate the magnitude and phase frequency response of the TT circuits. Additional simulation results for the total power dissipation, total harmonic distortion, intermodulation IM3, input and output referred noise spectral densities are also included for comparison purposes.
A 1.7-ns ACCESS TIME SRAM USING VARIABLE BULK BIAS WORDLINE-CONTROLLED TRANSISTORS
Authors: WANG CHUA-CHIN , SUNG GANG-NENG , HUANG CHI-CHUN , LEE CHING-LI , CHEN TIAN-HAU , LIN WUN-JI , HU RON
Published: February 2009

The design of a 1.7-ns access time prototype CMOS SRAM is presented. The threshold voltages of the wordline-controlled transistors (WCT) of the proposed memory cells are dynamically variable to achieve high-speed and low-power operations. When the cell is in the read or write (R/W) mode, the VTH of the wordline-controlled transistors is pulled low by increasing the bulk bias such that the drain current will be increased. By contrast, if it is idle in a standby mode, the bulk bias will be reduced by short-circuiting to a ground voltage to subside the leakage current. The highest operating clock rate of the proposed SRAM is measured to be 667 MHz. Moreover, the proposed memory cell possess high stability, the static noise margin is close to 635 mV given the worst case (75°C, FF model, VDD = 1.6 V ).
SUPERIMPOSED TRAINING-BASED CHANNEL ESTIMATION FOR MIMO-MB-OFDM UWB SYSTEMS
Authors: YANG QINGHAI , ZHU HUAMIN , KWAK KYUNG SUP
Published: February 2009

A novel channel estimation scheme based on superimposed training is proposed for multiple-input multiple-output multi-band orthogonal frequency division multiplexing ultra-wideband systems. The optimal training symbols are derived with respect to the least-square channel estimate mean square error. Simulation shows that the proposed scheme benefits much higher effective data throughput over the conventional method.
CREATING INDEPENDENT ADVOCATES FOR ENTREPRENEURS WITHIN GOVERNMENT: SOME REFLECTIONS ON THE SMALL BUSINESS COMMISSIONER MODEL
Authors: SCHAPER MICHAEL T.
Published: February 2009

This paper provides a critical overview of a recent attempt to create an independent statutory "voice" for small enterprises within the formal government bureaucracy in one Australian jurisdiction. It discusses the creation and eighteen months of activity of the Small Business Commissioner of the Australian Capital Territory.

In 2003 the ACT government foreshadowed that, as part of its strategy to create the most small-business-friendly location in Australia, it would establish a Small Business Commissioner as a statutory appointment. The Legislative Assembly passed the Small Business Commissioner Act in 2004 and activity began in March 2005.

The key activities of the Commissioner have been to examine small business complaints about ACT government agencies; to promote the use of mediation and/or other alternative dispute resolution tools for the settlement of disputes between small enterprises and other businesses; to provide independent advice to the Territory government about laws, regulations and policies that may affect small firms; to oversee the introduction of small business service charters within government agencies; and to establish a more "business friendly" service culture within ACT government agencies.

On one hand, it is clear that a Commissioner role has a potentially significant strategic importance for small and medium-sized enterprises, principally through the provision of independent commentary, pushing for red tape and regulatory reduction, and by providing mediation services and investigative functions. However, there are also some current problems with the role. These include potential overlap with other regulatory and investigative bodies; lack of formal compulsive powers; its dependence on political support for its effectiveness; insufficient resources; and the nature of the relationship it has with other government entities.
LEGITIMATING CHARACTERISTICS AND FIRM EMERGENCE
Authors: TORNIKOSKI ERNO T.
Published: February 2009

Most of the organizational theories take the existence of organizations for granted. Thus, attempts to understand success and failure at the nascent firm stage have often been conducted without an underlying theory to explain why some nascent firms succeed in becoming new firms while others do not. This study proposes that institutional theory offers an explanatory framework to explain firm emergence. Specifically, we argue that nascent firm becomes new firm thanks to resource endowments. The reliance on legitimating characteristics will grant a nascent firm an access to critical resources necessary for its emergence. We explore these ideas empirically and find support for our basic arguments.
FAMILY BUSINESS SUCCESSION: EVOLUTIONARY ECONOMICS APPROACH
Authors: KANSIKAS JUHA , KUHMONEN TUOMAS
Published: February 2009

This study analyses family business continuity from founder generation to the 2nd generation in terms of succession in the context of evolutionary economics. Two literature bases; family business succession and evolutionary thinking in organisational and economic change, are reviewed and combined to provide insights to understand the nature of family business succession. Operation of the key evolutionary forces — variation, selection, retention and struggle — in family business succession are illustrated. Regarding variation, there is a concern for understanding the importance of having enough diversity within the family firm, since this diversity of routines and competences comprises the pool of variation from which to select when the environment changes. With regards to selection, there is a concern for understanding the risk of selection bias easily rooted in the family firm culture: are some variations favoured in the selection of operating, investment and search routines because of family relations, emotions and values, including decisions on who will succeed and who will own the firm in the future. Elaboration and investigation of these concepts may help to identify special characteristics of the "family firm species" that are either beneficial or risky for the survival in the evolutionary struggle.
RESPONSIBLE ENTREPRENEURS: THE NETWORK EFFECTS
Authors: DRNOVSEK MATEJA , ZORN OTMAR , MARTINCIC MARJANA
Published: February 2009

By drawing from the social network literature, this research analyses relationships between strong and weak ties and network's benefits for personal success of entrepreneurs. The empirical analysis is context-based within a specific network where such multiplex ties are embedded. In particular, networks of entrepreneurs who adhere to socially responsible behaviour through activities in the Rotary International Organisation are examined. Prior research into entrepreneurship has shown the varying benefits of strong and weak ties for personal success. The aim of this study is to develop a conceptual model of strong and weak ties related benefits and their contribution to personal success to empirically test it within a specific network context. We identified the Rotary International Organisation as such a network. The findings of this study indicate that engaging in socially responsible behaviours through organised attempts, such as the Rotary International network, brings significant benefits for the personal success of entrepreneurs. The implications of our empirical analysis indicate that the socially responsible behaviour of entrepreneurs can be motivated through network enhanced joint values such as adherence to high ethical standards in doing business and advancement of an international fellowship of business and professional people.
PRELIMINARY VALIDATION OF MRI-BASED MODELING FOR EVALUATION OF JOINT MECHANICS
Authors: Thoomukuntla Bhaskar R. , Mciff Terence E. , Ateshian Gerard A. , Bilgen Mehmet , Toby E. Bruce , Fischer Kenneth J.
Published: February 2009

The objective of this study was to perform preliminary validation of MRI-based joint contact modeling methodology in the radiocarpal joints by comparison with the results of invasive radiocarpal contact measurements in three cadaver experiments. For each experiment, either Pressurex film or a Tekscan sensor was placed into the radiocarpal joints during a simulated grasp. Computer models were based on magnetic resonance imaging (MRI) of the cadaver specimens without load as well as on images acquired with the same loading used for the direct measurements. Geometric surface models of the radius, scaphoid, and lunate (including cartilage) were constructed from the images acquired without load. The carpal bone motions from the unloaded to the loaded state were determined using three-dimensional (3D) voxel image registration. Cartilage thickness was assumed to be uniform at 1.0 mm with an effective compressive modulus of 4 MPa. Resulting data included peak contact pressure, contact area, and contact force in the radioscaphoid and radiolunate joints. Contact area was also measured directly from MR images acquired with load and compared to model data. Qualitatively, there was good correspondence between the MRI-based model data and experimental data, with consistent relative size, shape, and location of radioscaphoid and radiolunate contact areas. Quantitative comparison of model and experimental data was reasonable, but less consistent. Contact area from the MRI-based model was always similar to the contact area measured directly from the MR images. With additional experiments, we believe that MRI-based joint contact modeling will soon be fully validated in the radiocarpal joints.
HEIGHT AND RADIOGRAPHIC OSTEOARTHRITIS: AN EPIDEMIOLOGIC ASSESSMENT — SHORT COMMUNICATION
Authors: Wilder Frances Vaughn , Leaverton Paul E. , Rogers Matthew W.
Published: February 2009

Purpose: To epidemiologically assess the gender-specific relationship between height and radiographic osteoarthritis (OA) of the knee, hand, foot, and cervical spine. Methods: Data collected from men (N = 1090) and women (N = 2441) aged 40 years and older participating in the Clearwater Osteoarthritis Study (1988–current) were used (N = 3531). Physical exams including radiographs were conducted. The Kellgren and Lawrence ordinal scale was used to determine evidence of radiographic OA. Results: There is a modest, albeit consistent, increase in OA prevalence among shorter-stature study subjects at all four sites in women and at two sites in men (hands and cervical spine). Our adjusted findings suggest that shorter stature is a risk factor for OA for the hands, feet, and cervical spine, with odds ratios varying between 1.25 and 1.82. After adjusting for body mass index and age, this relationship maintained statistical significance among women for hand OA. (OR = 1.57; p = 0.0001) and feet OA (OR = 1.41; p - value = 0.009). Curiously, no significant association was indicated between height and knee OA for either gender. Conclusions: Shorter stature appears to be associated with an elevated risk of OA, but particularly so for women. Future epidemiologic studies examining this relationship can offer insight into skeletal growth and development knowledge, thus further elucidating the etiology of OA.
BRIDGE INTEGRITY ASSESSMENT BY CONTINUOUS WAVELET TRANSFORMS
Authors: ALVANDI A. , BASTIEN J. , GRÉGOIRE E. , JOLIN M.
Published: February 2009

The potential of continuous wavelet transforms for damage assessment of existing bridges is investigated herein. Different types of continuous wavelet transforms have been under investigation and the most effective ones have been introduced in a toolbox to automate the damage assessment procedure. In this paper, the performance of the wavelet approach and the influence of different parameters in the damage assessment procedures are studied through two examples: a simply supported beam and a three-span concrete bridge. Applying the wavelet transforms to a structure's static and/or dynamic response showed promising results with regard to localization of structural modification or damage. This paper underlines the high sensitivity of the wavelet analysis to damage intensity and its ability to be applied directly to the damaged data. These key characteristics could lead to this approach becoming one of the best for structural health monitoring of existing bridges in the near future.
ANALYTICAL AND EXPERIMENTAL STUDIES ON 400 kV S/C PORTAL-TYPE GUYED TOWERS
Authors: PRASAD RAO N. , MOHAN S. J. , ROKADE R. P. , BALA GOPAL R.
Published: February 2009

The experimental and analytical behavior of 400 kV S/C portal-type guyed towers under different loading conditions is presented. The portal-type tower essentially consists of two masts extending outward in the transverse direction from the beam level to the ground. In addition, two sets of guys connected at the ground level project outward along the longitudinal axes and converge in the transverse axes. The experimental behavior of the guyed tower is compared with the results of finite element analysis. The 400 kV portal-type guyed towers with III and IVI type insulator strings are analyzed using finite element software. Full scale tower test results are verified through comparison with the results of the finite element analysis. The initial prestress in the guys is allowed to vary from 5% to 15% in the finite element modeling. The effect of prestress variation of the guys on the tower behavior is also studied.
FLEXURAL INSTABILITY OF VISCOELASTIC SPINNING CYLINDERS PARTIALLY FILLED WITH LIQUID
Authors: FIROUZ-ABADI R. D. , HADDADPOUR H.
Published: February 2009

This paper deals with the determination of free vibration characteristics and instability conditions of flexible spinning cylinders partially filled with fluid. Using the linearized Navier–Stokes equations for the incompressible, inviscid flow, a 2D model is developed for fluid motion at each section of the cylinder. The forces exerted on the cylinder wall as a result of the fluid motion are calculated as functions of lateral acceleration of the cylinder axis in the Laplace domain. Applying the Hamilton principle, the governing equations of flexural motion of the cylinder are derived and then combined with the equations describing the fluid forces to obtain the coupled field equations of the structural motion and the liquid sloshing dynamics. Using the obtained model, the free vibration and the stability conditions of the cylinder as well as the effect of material viscoelasticity on the stability boundaries are examined. The results of the stability analysis are presented for a number of examples, and some conclusions are outlined.
ACTIVE MULTIPLE TUNED MASS DAMPERS FOR REDUCTION OF UNDESIRABLE OSCILLATIONS OF STRUCTURES UNDER WIND LOADS
Authors: LI CHUNXIANG , HAN BINGKANG , ZHANG JINGYI , QU YAN , LI JINHUA
Published: February 2009

Active multiple tuned mass dampers (AMTMDs) consisting of several active tuned mass dampers (ATMDs) with uniform distribution of natural frequencies have been proposed for vibration mitigation of structures under wind loads. In this regard, the optimum parameter criterion is defined as the minimization of the root-mean-square (RMS) displacement and acceleration responses of the structure with the AMTMD. Meanwhile, the effectiveness criterion is defined as the ratio of the minimum RMS displacement and RMS acceleration of the structure with the AMTMD to those without the devices, respectively referred to as the displacement and acceleration reduction factors (DRF and ARF). With these two criteria, the influences of the selective parameters on the effectiveness and robustness of the devices for vibration control under wind loads are studied. In addition, the stroke of the AMTMD is examined by quantitatively assessing the RMS displacement of each ATMD. Results indicate that in comparison with a single ATMD, the AMTMD can cause more reduction in the displacement and acceleration responses of the structure under wind loads. The stroke of the AMTMD is greater based on the ARF than the DRF criterion. In particular, the simulation results in the time domain confirm that by resorting to the AMTMD, a large control force can indeed be decentralized into many smaller control forces without losing the level of response reduction.
PASSIVE RESPONSE CONTROL SYSTEMS FOR SEISMIC RESPONSE REDUCTION: A STATE-OF-THE-ART REVIEW
Authors: PARULEKAR Y. M. , REDDY G. R.
Published: February 2009

Research and development of seismic response control devices has gained prime importance recently, due to an increased number of devastating earthquakes. Passive control systems are now accepted all over the world and hence research in this area is continuing to develop reliable, efficient and cost effective devices along with constitutive modeling. This paper begins with qualitative description and comparison of passive, active and semiactive control systems. Further, it mentions advantages of passive control systems over the others. A detailed literature review of passive devices is then provided which includes the historical development of the devices, their dynamic behavior, testing of these devices incorporated in the structural models and their analytical formulations. The pros and cons of these devices in retrofitting of structures and their first and recent applications in a wide variety of structures are also discussed. The passive response control systems that are discussed include viscoelastic dampers, yielding dampers, viscous dampers, friction dampers, tuned mass dampers, tuned liquid dampers, tuned liquid column dampers, superelastic dampers, like shape memory alloy dampers and base isolators.
ELASTIC BUCKLING OF THIN-WALLED CYLINDERS UNDER WIND LOADING: AN EXPERIMENTAL STUDY
Authors: PIRCHER MARTIN , LECHNER BERNHARD , TRUTNOVSKY HELMUT
Published: February 2009

Thin-walled cylindrical structures have been found to display three distinctly different stability failure modes under wind loading, depending on their geometric and material properties. In low cylinders the radial compression at the meridian facing the wind causes a buckling mode similar to that for cylinders under constant radial compression, while very long cylinders display a failure mode characterized by buckling in the lower third of the structure at the side which faces away from the wind. The failure of medium height cylinders is characterized by a number of horizontal, ripple-like buckles in an area around the upper half of the meridian which faces the wind. In an ongoing experimental study, a series of small-scale specimens with a wide range of geometric parameters is being tested in a wind tunnel. To the knowledge of the authors, this is the first time that the particular buckling mode for medium height cylinders has been documented in an experiment. The present paper gives a summary of the results gained from this study so far and compares them qualitatively to those of a previous numerical study.
COUNTING OF OLIGOMERS IN SEQUENCES GENERATED BY MARKOV CHAINS FOR DNA MOTIF DISCOVERY
Authors: SHAN GAO , ZHENG WEI-MOU
Published: February 2009

By means of the technique of the imbedded Markov chain, an efficient algorithm is proposed to exactly calculate first, second moments of word counts and the probability for a word to occur at least once in random texts generated by a Markov chain. A generating function is introduced directly from the imbedded Markov chain to derive asymptotic approximations for the problem. Two Z-scores, one based on the number of sequences with hits and the other on the total number of word hits in a set of sequences, are examined for discovery of motifs on a set of promoter sequences extracted from A. thaliana genome. Source code is available at .
CAN COMPLEX CELLULAR PROCESSES BE GOVERNED BY SIMPLE LINEAR RULES?
Authors: SELVARAJOO KUMAR , TOMITA MASARU , TSUCHIYA MASA
Published: February 2009

Complex living systems have shown remarkably well-orchestrated, self-organized, robust, and stable behavior under a wide range of perturbations. However, despite the recent generation of high-throughput experimental datasets, basic cellular processes such as division, differentiation, and apoptosis still remain elusive. One of the key reasons is the lack of understanding of the governing principles of complex living systems. Here, we have reviewed the success of perturbation–response approaches, where without the requirement of detailed in vivo physiological parameters, the analysis of temporal concentration or activation response unravels biological network features such as causal relationships of reactant species, regulatory motifs, etc. Our review shows that simple linear rules govern the response behavior of biological networks in an ensemble of cells. It is daunting to know why such simplicity could hold in a complex heterogeneous environment. Provided physical reasons can be explained for these phenomena, major advancement in the understanding of basic cellular processes could be achieved.