bluuebunny/crossref_metadata_2025 huggingface dataset:
Socioeconomic Vulnerability and Adaptation to Environmental Risk: A Case Study of Climate Change and Flooding in Bangladesh
Authors: Brouwer Roy , Akter Sonia , Brander Luke , Haque Enamul
Published: May 2007

In this article we investigate the complex relationship between environmental risk, poverty, and vulnerability in a case study carried out in one of the poorest and most flood‐prone countries in the world, focusing on household and community vulnerability and adaptive coping mechanisms. Based upon the steadily growing amount of literature in this field we develop and test our own analytical model. In a large‐scale household survey carried out in southeast Bangladesh, we ask almost 700 floodplain residents living without any flood protection along the River Meghna about their flood risk exposure, flood problems, flood damage, and coping mechanisms. Novel in our study is the explicit testing of the effectiveness of adaptive coping strategies to reduce flood damage costs. We show that, households with lower income and less access to productive natural assets face higher exposure to risk of flooding. Disparity in income and asset distribution at community level furthermore tends to be higher at higher risk exposure levels, implying that individually vulnerable households are also collectively more vulnerable. Regarding the identification of coping mechanisms to deal with flood events, we look at both the ex ante household level preparedness for flood events and the ex post availability of community‐level support and disaster relief. We find somewhat paradoxically that the people that face the highest risk of flooding are the least well prepared, both in terms of household‐level ex ante preparedness and community‐level ex post flood relief.
Some Limitations of Aggregate Exposure Metrics
Authors: Cox Louis Anthony (Tony) , Popken Douglas A.
Published: May 2007

Aggregate exposure metrics based on sums or weighted averages of component exposures are widely used in risk assessments of complex mixtures, such as asbestos‐associated dusts and fibers. Allowed exposure levels based on total particle or fiber counts and estimated ambient concentrations of such mixtures may be used to make costly risk‐management decisions intended to protect human health and to remediate hazardous environments. We show that, in general, aggregate exposure information alone may be inherently unable to guide rational risk‐management decisions when the components of the mixture differ significantly in potency and when the percentage compositions of the mixture exposures differ significantly across locations. Under these conditions, which are not uncommon in practice, aggregate exposure metrics may be “worse than useless,” in that risk‐management decisions based on them are less effective than decisions that ignore the aggregate exposure information and select risk‐management actions at random. The potential practical significance of these results is illustrated by a case study of 27 exposure scenarios in El Dorado Hills, California, where applying an aggregate unit risk factor (from EPA's IRIS database) to aggregate exposure metrics produces average risk estimates about 25 times greater—and of uncertain predictive validity—compared to risk estimates based on specific components of the mixture that have been hypothesized to pose risks of human lung cancer and mesothelioma.
Bootstrap Estimation of Benchmark Doses and Confidence Limits with Clustered Quantal Data
Authors: Zhu Yiliang , Wang Tao , Jelsovsky Jenny Z.H.
Published: May 2007

The benchmark dose (BMD) is an exposure level that would induce a small risk increase (BMR level) above the background. The BMD approach to deriving a reference dose for risk assessment of noncancer effects is advantageous in that the estimate of BMD is not restricted to experimental doses and utilizes most available dose‐response information. To quantify statistical uncertainty of a BMD estimate, we often calculate and report its lower confidence limit (i.e., BMDL), and may even consider it as a more conservative alternative to BMD itself. Computation of BMDL may involve normal confidence limits to BMD in conjunction with the delta method. Therefore, factors, such as small sample size and nonlinearity in model parameters, can affect the performance of the delta method BMDL, and alternative methods are useful. In this article, we propose a bootstrap method to estimate BMDL utilizing a scheme that consists of a resampling of residuals after model fitting and a one‐step formula for parameter estimation. We illustrate the method with clustered binary data from developmental toxicity experiments. Our analysis shows that with moderately elevated dose‐response data, the distribution of BMD estimator tends to be left‐skewed and bootstrap BMDL s are smaller than the delta method BMDL s on average, hence quantifying risk more conservatively. Statistically, the bootstrap BMDL quantifies the uncertainty of the true BMD more honestly than the delta method BMDL as its coverage probability is closer to the nominal level than that of delta method BMDL. We find that BMD and BMDL estimates are generally insensitive to model choices provided that the models fit the data comparably well near the region of BMD. Our analysis also suggests that, in the presence of a significant and moderately strong dose‐response relationship, the developmental toxicity experiments under the standard protocol support dose‐response assessment at 5% BMR for BMD and 95% confidence level for BMDL.
Capital Allocation for Insurance Companies—What Good IS IT?
Authors: Gründl Helmut , Schmeiser Hato
Published: May 2007

Abstract

In their 2001 Journal of Risk and Insurance article, Stewart C. Myers and James A. Read Jr. propose to use a specific capital allocation method for pricing insurance contracts. We show that in their model framework no capital allocation to lines of business is needed for pricing insurance contracts. In the case of having to cover frictional costs, the suggested allocation method may even lead to inappropriate insurance prices. Beside the purpose of pricing insurance contracts, capital allocation methods proposed in the literature and used in insurance practice are typically intended to help derive capital budgeting decisions in insurance companies, such as expanding or contracting lines of business. We also show that net present value analyses provide better capital budgeting decisions than capital allocation in general.
Financial Distress in Australian General Insurers
Authors: Sharpe Ian G. , Stadnik Andrei
Published: May 2007

Abstract

We develop and test a statistical model to identify Australian general insurers experiencing financial distress over the 1999–2001 period. Using a logit model and two measures of financial distress we are able to predict, with reasonable confidence, the insurers more likely to be distressed. They are generally small and have low return on assets and cession ratios. Relative to holdings of liquid assets they have high levels of property and reinsurance assets, and low levels of equity holdings. They also write more overseas business, and less motor insurance and long‐tailed insurance lines, relative to fire and household insurance.
The Jakobid Flagellates: Structural Features of Jakoba, Reclinomonas and Histiona and Implications for the Early Diversification of Eukaryotes
Authors: O'KELLY CHARLES J.
Published: May 2007

ABSTRACT. Jakobid flagellates are small, free‐living, bacterivorous heterotrophs, with similar morphology, asexual reproduction, and nucleocytoplasmic ultrastructural features at interphase and during cell division. Jakoba is typified by aloricate trophic cells, each containing a branched mitochondrion with prominent nucleoids and flattened cristae. Reclinomonas and Histiona are characterized by loricate trophic cells, each with an unbranched mitochondrion without prominent nucleoids or otherwise differentiated regions and bearing tubular cristae. An undescribed genus is typified by aloricate cells, each with an unbranched mitochondrion bearing discoidal cristae. I propose, on the basis of cytoskeletal architecture and other structural and developmental features, that jakobids are ancestral mitochondrial protists, sister taxa to the amitochondnal retortamonads and ancestral to diverse lineages of mitochondrial eukaryotes. Application of different classification paradigms produces different family‐level taxonomies for jakobids.
Sol–Gel Preparation and Characterization of Lithium Disilicate Glass–Ceramic
Authors: Zhang T Bo , Easteal Allan J. , Edmonds Neil R. , Bhattacharyya Debes
Published: May 2007

A sol–gel process is described for preparation of crystalline lithium disilicate (Li2Si2O5) from tetraethylorthosilicate and lithium ethoxide. The glass network structure and crystallinity resulting from heat treatment at temperatures from 150° to 900°C were investigated by nuclear magnetic resonance, X‐ray diffraction, and differential scanning calorimetry/thermogravimetric analysis. Q3 structural units (SiO4 tetrahedra with three bridging oxygen atoms) formed in the amorphous gel at a low temperature (≤150°C) persist to elevated temperature (≤500°C) and directly transform to crystalline Li2Si2O5 at about 550°C. The heating schedule slightly affects the crystalline phase transformation.
Nitridation of Silica Characterized by High‐Energy X‐Ray Diffraction Technique
Authors: Wakihara Toru , Yamakawa Tomohiro , Tatami Junichi , Komeya Katsutoshi , Meguro Takeshi , Kohara Shinji
Published: May 2007

The structure of amorphous silicon oxynitride formed under nitridation conditions using ammonia gas, before the onset of silicon nitride crystallization, is determined employing high‐energy X‐ray diffraction (HEXRD) technique. The derived real‐space function suggests that smaller ring structures, especially 3R and 4R (R: ring), which are the dominant rings in crystalline silicon nitride, are not major species in amorphous silicon oxynitride, and form in the latter part of the silicon nitride crystallization.
Solid Solubility and Thermal Expansion in a LaPO4–YPO4System
Authors: Mogilevsky P. , Boakye E. E. , Hay R. S.
Published: May 2007

The composition and lattice parameters of co‐precipitated (La0.3Y0.7) orthophosphate were studied using X‐ray diffraction (XRD), transmission electron microscopy (TEM), and energy dispersive X‐ray spectroscopy (EDX). The results indicate that the as‐precipitated powder consists of single‐phase (La0.3Y0.7PO4·H2O) rhabdophane nanoparticles. Heat treatment at 950°C caused the decomposition of rhabdophane into a (La1−xYx)PO4monazite solid solution and YPO4xenotime. The solid solubility of Y in LaPO4monazite from 1000° to 1600°C was studied using XRD, TEM, and EDX. The implications of the findings for controlling the coefficient of thermal expansion of the prospective two‐phase monazite–xenotime fiber coatings for ceramic composites applications are discussed.
Competencies of genetic nursing practise in Japan: A comparison between basic and advanced levels
Authors: ARIMORI Naoko , NAKAGOMI Satoko , MIZOGUCHI Michiko , MORITA Minako , ANDO Hiroto , MORI Akiko , HORIUCHI Shigeko , HOLZEMER William L.
Published: May 2007

Aim:  The purpose of this study was to identify the competencies of genetic nursing practise required for general and genetic nurses.

Methods:  We conducted a four‐stage survey using a Delphi process. We conducted an interview with 27 nurses who were involved in genetics‐related care and extracted 89 items in seven categories. In the second survey, we mailed a questionnaire to 20 experts in genetics. In the third and fourth surveys, we asked 491 health‐care providers, including nurses and physicians, who were involved in genetics‐related care and agreed to participate in the study at 113 institutions in 40 prefectures. The respondents were asked to choose one of three options in each of 89 items: “A: General nurse’s role”, “B: Genetic nurse’s role”, and “C: Not appropriate as the nurse’s role”. The data were collected from August 2000 to March 2001. There were 295 final subjects, and the response rate was 60%.

Results:  The competencies required for general nurses were identified as “living support”, “psychological support”, and “identification of the client’s wishes”, while those required for genetic nurses were “provision and exchange of accurate genetic information”, “referral to and collaboration with other organisations”, and “client support to understand disease.”

Conclusions:  These results suggest a direction for genetic nursing curricula. It is our challenge to incorporate genetics into the education programming.
RELATIONSHIP BETWEEN TASTE AND CHEWING PATTERNS OF VISCO‐ELASTIC MODEL FOODS
Authors: ALFONSO MATILDE , NEYRAUD ERIC , BLANC OLIVIER , PEYRON MARIE AGNES , DRANSFIELD ERIC
Published: May 2007

The jaw movements and muscular activity of masticatory muscles of five assessors, having bitterness thresholds about 8 μM quinine in water, were monitored throughout chewing of similar strength gelatin gels containing 0, 40, 70 or 100 μM quinine. Gel bitterness ratings were not related to sensory texture which was 78kN/m2 by shear test. On average, 100 μM quinine gels were as bitter as 7 to 30 μM quinine in water, depending on the assessor. Chewing patterns were not affected by concentration of quinine in the gels. During mastication of acceptable gels, there appears to be no feedback from taste to the motor control of mastication. In gels of the same consistency and the same concentration of quinine, assessors who chewed more rated higher for bitterness. The implications for mimicking mastication by machine and the training of assessors for solid foods are discussed.
Congressional Ethics: The Fox and the Henhouse1
Authors: Patten Joseph N.
Published: May 2007

Members of Congress have conflicting responsibilities between advancing the public's interest while advocating for the private interests of constituents. This research examines the association between political corruption and the increased devotion to constituent casework. It creates a congressional corruption matrix that gives rise to four types of political corruption illuminated through descriptions of the Abscam Scandal, the Duke Cunningham Scandal, the Keating Five Scandal, and the Jack Abramoff Scandal. It makes a distinction between individual and institutional forms of corruption and differentiates between personal gain and career advancing varieties of corruption. This article contends that Congress is disinclined to enact and enforce substantive reforms in career advancing forms of corruption because of a shared institutional value in expanding politically beneficial activities.
Partisan Bias in the Electoral College: Cheap States and Wasted Votes1
Authors: Ardoin Phillip J. , Parsons Bryan M.
Published: May 2007

This article dissects the sources of partisan bias in the institutional structure of the U.S. electoral college. Conventional wisdom and results of recent presidential elections suggest that the electoral college is biased in favor of the Republican Party. While previous empirical studies have challenged this conventional wisdom, George Bush's 2000 electoral college victory revived this debate. Our research provides a direct analysis of the multiple sources of bias within the electoral college and examines their individual impact on each party's electoral fortunes over the last eleven elections (1964‐2004) with particular attention on the 2000 and 2004 presidential elections. Our results are in line with previous analyses indicating no significant bias within the electoral college. We conclude that parties and their presidential candidates are rational political actors who utilize sophisticated campaign strategies which allow them to efficiently employ their resources and limit any institutional disadvantages they may face.
Buyer's Remorse: The Relationship between Local Economic Circumstances and Special District Policies
Authors: Bauroth Nicholas
Published: May 2007

Burns argues that the creation of local governments is not a politically neutral act. From the 1950s through the 1980s, many governments in the United States were incorporated to provide publicly funded infrastructure for private developments and reduce the tax burdens of manufacturers. Although it is unclear whether or not the factors necessary for the formation of special districts had any impact upon subsequent district policies in either 1972, 1982, or 1992. Using U.S. Bureau of the Census data sets, I demonstrate that manufacturers maintained their influence over municipality‐sized special districts, but not county‐sized districts. The study also finds that private development had some impact upon the policies of county‐sized districts as did the racial composition of those counties. Finally, state statutes restricting local governmental behavior had a strong effect upon the policies of both county‐sized and municipal‐sized districts for most periods under examination.
5

kWe

LPG Hydrogen Generator for Polymer Electrolyte Fuel Cells: Momentum-Based Modeling of an Autothermal Reformer
Authors: Cipitì F. , Recupero V. , Pino L. , Vita A. , Laganà M.
Published: May 2007

This paper presents a two-dimensional model to describe the gas flow in an integrated reactor, developed at the CNR-ITAE Institute, and aimed to design a βeta5kWe hydrogen generator, named HYGen II, to integrate with polymer electrolyte fuel cells (PEFCs) for residential applications. The model is able to simulate velocity profiles in order to investigate the reactor geometrical key parameters. The unit can convert light hydrocarbons (methane, propane, LPG, butane) into a hydrogen rich mixture. The processing unit consists of an innovative integrated dual bed reactor, filled with pellet catalysts: a proprietary Pt∕CeO2 autothermal reforming (ATR) and a commercial intermediate temperature water gas shift (ITWS). For the last clean-up step, a single-stage preferential oxidation (PROX) process has been adopted. Moreover, an automation system to monitor operating conditions and control plant equipment has been designed.
CFD
Study of Heat Transfer in a Spark-Ignition Engine Combustion
Chamber
Authors: Noori A.
R. , Rashidi M.
Published: May 2007

The objective of this study is the thermal investigation of a typical spark-ignition (SI) engine combustion chamber with particular focus in determination of the locations where the heat flux and heat transfer coefficient are highest. This subject is an important key for some design purposes especially thermal loading of the piston and cylinder head. To this end, CFD simulation using the KIVA-3V CFD code on a PC platform for flow, combustion, and heat transfer in a typical SI engine has been performed. Some results including the temporal variation of the area-averaged heat flux and heat transfer coefficient on the piston, combustion chamber, and cylinder wall are presented. Moreover, the temporal variation of the local heat transfer coefficient and heat flux along a centerline on the piston as well as a few locations on the combustion chamber wall are shown. The investigation reveals that during the combustion period, the heat flux and heat transfer coefficient vary substantially in space and time due to the transient nature of the flame propagation. For example, during the early stages of the flame impingement on the wall, the heat flux undergoes a rapid increase by as much as around 10 times the preimpingement level. In other words, the initial rise of the heat flux at any location is related to the time of the flame arrival at that location.
Radiative Properties of MoO3 and Al Nanopowders From Light-Scattering Measurements
Authors: Begley S. M. , Brewster M. Q.
Published: May 2007

The combustion behavior of nanometer-scale energetic materials is much different than micron size or larger materials. Burning rates up to 950 m∕s have been reported for a thermite composition of nanosized aluminum and molybdenum trioxide. The energy transport mechanisms in the reactive wave are still uncertain. The relative contribution of radiation has not yet been quantified. To do so analytically requires dependent scattering theory, which has not yet been fully developed. Radiative properties for nanoaluminum and nanomolybdenum-trioxide were obtained experimentally by comparing light scattering measurements on a one-dimensional slab of powder with multiple-scattering simulations using Monte Carlo and discrete ordinate methods. The equivalent isotropic-scattering extinction coefficient for close-packed molybdenum trioxide (MoO3) nanopowder was found to be 5900±450cm−1; the equivalent isotropic-scattering albedo was 0.97±0.035. Aluminum (Al), which proved to be more difficult to work with, had an albedo of 0.35 and 0.38 from two tests. The radiative conductivity based on the MoO3 results is two orders of magnitude less than the diffusive thermal conductivity, indicating that radiation is not a dominant heat transfer mode for the reactive wave propagation of nanothermites under optically thick conditions.
Transfer From a Droplet at High Peclet Numbers With Heat Generation: Interior Problem
Authors: Souccar Adham , Oliver Douglas L.
Published: May 2007

Transient heat transfer from a droplet with heat generation is investigated. It is assumed that the bulk of the thermal resistance resides in the droplet. Two cases were investigated: low Peclet flows and very high Peclet flows. As expected, it was found that the temperature rise due to the heat generation was less for high Peclet flows. In addition, the temperature profile responds more quickly for high Peclet flows. This analysis is also applicable for mass transfer with a zero-order reaction.
Parameters Affecting the Performance of a Residential-Scale Stationary Fuel Cell System
Authors: Davis Mark W. , Fanney A. Hunter , LaBarre Michael J. , Henderson Kenneth R. , Dougherty Brian P.
Published: May 2007

Researchers at the National Institute of Standards and Technology have measured the performance of a residential fuel cell system when subjected to various environmental and load conditions. The system, which uses natural gas as its source fuel, is capable of generating electrical power at three nominal power levels (2.5, 4.0, and 5.0kW) while providing thermal energy for user-supplied loads. Testing was conducted to determine the influence of ambient temperature, relative humidity, electrical load, and thermal load on system performance. Steady-state and transient tests were conducted. The steady-state tests were performed in accordance with the American Society of Mechanical Engineering Fuel Cell Power Systems Performance Test Code (PTC-50) for fuel cell power systems. The results of the investigation are being used to develop a proposed rating procedure for residential fuel cell units.
Optimum Battery Size for Fuel Cell Hybrid Electric Vehicle— Part I
Authors: Sundström Olle , Stefanopoulou Anna
Published: May 2007

This study explores different hybridization levels of a midsized vehicle powered by a polymer electrolyte membrane fuel cell stack. The energy buffer considered is a lead-acid-type battery. The effects of the battery size on the overall energy losses for different drive cycles are determined when dynamic programming determines the optimal current drawn from the fuel cell system. The different hybridization levels are explored for two cases: (i) when the battery is only used to decouple the fuel cell system from the voltage and current demands from the traction motor to allow the fuel cell system to operate as close to optimally as possible and (ii) when regenerative braking is included in the vehicle with different efficiencies. The optimal power-split policies are analyzed to quantify all the energy losses and their paths in an effort to clarify the hybridization needs for a fuel cell vehicle. Results show that without any regenerative braking, hybridization will not decrease fuel consumption unless the vehicle is driving in a mild drive cycle (city drive with low speeds). However, when the efficiency of the regenerative braking increases, the fuel consumption (total energy losses) can be significantly lowered by choosing an optimal battery size.
Deleterious effects of short-term, high-intensity exercise on immune function: evidence from leucocyte mitochondrial alterations and apoptosis
Authors: Tuan T-C , Hsu T-G , Fong M-C , Hsu C-F , Tsai K K C , Lee C-Y , Kong C-W
Published: May 2007

Background:

Although moderate exercise can benefit health, acute and vigorous exercise may have the opposite effect. Strenuous exercise can induce alterations in the physiology and viability of circulating leucocytes, which have a causal relationship with exercise-induced immune distress.

Objectives:

To investigate the use of mitochondrial transmembrane potential (MTP), a functional marker of the energy and viability status of leucocytes, for monitoring the immunomodulating effects of short-term, high-intensity exercise.

Methods:

12 healthy volunteers with a mean Vo2maxof 70.4 ml/kg/min carried out 3 consecutive days of high-intensity exercise (85% of Vo2maxfor 30 min every day). Blood samples were collected at multiple time points immediately before and after each exercise session and at 24 and 72 h after the completion of exercise. Leucocyte MTP, apoptosis and circulatory inflammation markers were measured by flow cytometry and enzyme-linked immunosorbent assays.

Results:

MTP of peripheral blood leucocytes had declined immediately after the first exercise session and remained subnormal 24 h later. It did not normalise until 72 h after exercise. The sequential changes in MTP were consistent among the three leucocyte subpopulations (polymorphonuclear neutrophils, lymphocytes and monocytes) and were significant (p<0.05). Leucocytes displayed a gradual and incremental change in their propensity for apoptosis during and after exercise. Similarly, plasma concentrations of tumour necrosis factor-α and soluble Fas ligand were raised during the exercise sessions and had not normalised by 72 h after the completion of exercise. Correlation between changes in leucocyte MTP and plasma concentrations of tumour necrosis factor-α and soluble Fas ligand was variable, but significant for polymorphonuclear neutrophils and lymphocytes (p<0.05).

Conclusions:

Short-term, high-intensity exercise can lead to a significant and prolonged dysfunction of the mitochondrial energy status of peripheral blood leucocytes, which is accompanied by an increased propensity for apoptosis and raised pro-inflammatory mediators. These results support the immunosuppressive effects of excessive exercise and suggest that MTP is a useful marker of these effects.
Expression ofCaPTC7is developmentally regulated during serum-induced morphogenesis in the human fungal pathogen Candida albicans
Authors: Wang Jihong , Yan Zhihui , Shen Shi-Hsiang , Whiteway Malcolm , Jiang Linghuo
Published: May 2007

Type 2C protein phosphatases (PP2C) represent a diversified protein phosphatase family and play various roles in cells. We previously identified and characterized a novel PP2C phosphatase encoded by the CaPTC7 gene in the human fungal pathogen Candida albicans . The CaPtc7p has 365 amino acids with a PP2C core domain at the C terminus and an additional 116-residue N-terminal sequence containing a mitochondrion-targeting sequence. Here, we show that CaPtc7p is indeed localized in the mitochondrion, the only eukaryotic PP2C phosphatase that has been directly shown to reside in the mitochondrion, suggesting its potential role in the regulation of mitochondrial physiology. Furthermore, we show that the expression of CaPTC7 at both transcriptional and protein levels is developmentally regulated during the serum-induced morphogenesis of C. albicans cells. However, disruption of the two alleles of CaPTC7 does not affect cell viability or filamentous development in C. albicans.
SPIKING NEURALPSYSTEMS: AN EARLY SURVEY
Authors: PĂUN GHEORGHE , PÉREZ-JIMÉNEZ MARIO J. , SALOMAA ARTO
Published: May 2007

Spiking neural P systems were introduced in the end of the year 2005, in the aim of incorporating in membrane computing the idea of working with unique objects ("spikes"), encoding the information in the time elapsed between consecutive spikes sent from a cell/neuron to another cell/neuron. More than one dozen of papers where written in the meantime, clarifying many of the basic properties of these devices, especially related to their computing power.

The present paper quickly surveys the basic ideas and the basic results, presenting a complete to-date bibliography, and also giving a completing result related to the normal forms possible for spiking neural P systems: we prove that the indegree of such systems (the maximal number of incoming synapses of neurons) can be bounded by 2 without losing the computational completeness.

A series of research topics and open problems are formulated.
PROCEDURES FOR COMPUTING THE MAXIMUM WITH DNA
Authors: FUJIWARA AKIHIRO , KAMIO SATOSHI , TAKEHARA AKIKO
Published: May 2007

In recent works for high performance computing, computation with DNA strands, that is, DNA computing, has considerable attention as one of non-silicon based computing. In this paper, we propose three procedures for computing the maximum of n binary numbers of m bits, which are represented with O(mn) DNA strands. The first procedure computes the maximum of the binary numbers in O(m) steps using O(n) kinds of DNA strands. The second and third procedures also compute the maximum in O( log n) and O(1) steps using O(mn) and O(mn2) kinds of DNA strands, respectively.
INTERACTION OF ELECTRON AND NUCLEAR SPINS IN QUANTUM WELLS
Authors: MURAKI KOJI , KUMADA NORIO , HIRAYAMA YOSHIRO
Published: May 2007

We describe our resistively detected nuclear-spin relaxation measurements on bilayer electron systems in double quantum wells. The measurements were carried out to study the compressible-incompressible transition at total filling factor νtot = 1 and the canted antiferromagnetic order and its Goldstone mode predicted for νtot = 2. The data demonstrate how nuclear-spin relaxation can shed light on spin/pseudospin order and associated phase transitions that may not be visible through conventional transport or optical measurements.
EDGE STATES AND TRAJECTORIES IN QUANTUM DOTS: PROBING THE QUANTUM-CLASSICAL TRANSITION
Authors: FERRY D. K. , AKIS R. , BIRD J. P.
Published: May 2007

Edge states have been a backbone of our understanding of the experimental basis of the quantum Hall effect for quite some time. Interestingly, this comprises a quantum system with well defined currents and particle trajectories. The role of trajectories in quantum mechanics has been a problematic question of interpretation for quite some time, and the open quantum dot is a natural system in which to probe this question. Contrary to early speculation, a set of well defined quantum states survives in the open quantum dot. These states are the pointer states and provide a transition into the classical states that can be found in these structures. These states provide resonances, which are observable as oscillatory behavior in the magnetoconductance of the dots. But, they have well defined current directions within the dots. Consequently, one expects trajectories to be a property of these states as well. As one crosses from the low to the high field regime, quite steady trajectories and consequent wave functions can easily be identified and examined. In this talk, we review the current understanding and the support for the decoherence theory.
QUANTUM DOTS BASED ON PARABOLIC QUANTUM WELLS: IMPORTANCE OF ELECTRONIC CORRELATIONS
Authors: IHN THOMAS , ELLENBERGER CHRISTOPH , ENSSLIN KLAUS , YANNOULEAS CONSTANTINE , LANDMAN UZI , DRISCOLL DAN C. , GOSSARD ART C.
Published: May 2007

We present measurements and theoretical interpretation of the magnetic field dependent excitation spectra of a two-electron quantum dot. The quantum dot is based on an Al x Ga 1-x As parabolic quantum well with effective g⋆-factor close to zero. Results of tunneling spectroscopy of the four lowest states are compared to exact diagonalization calculations and a generalized Heitler–London approximation and good agreement is found. Electronic correlations, associated with the formation of an H 2-type Wigner molecule, turn out to be very important in this system.
POTENTIAL IMAGING IN QUANTUM HALL DEVICES BY OPTICAL FIBER BASED POCKELS MEASUREMENT
Authors: DOHI M. , YONAMINE R. , OTO K. , MURO K.
Published: May 2007

We have developed an optical-fiber-based Hall potential imaging system using the Pockels effect in GaAs/AlGaAs two dimensional electron systems (2DES) in the quantum Hall regime to investigate current distributions. The mapping of the Hall potential shows the current concentration at the bulk region of 2DES samples, where the critical current depends on the channel width sub-linearly. We report in detail the experimental techniques of the imaging system operating in high magnetic fields.
HIGH MAGNETIC FIELD STUDY OF 2D ELECTRON GAS IN AlP
Authors: SEMTSIV M. P. , DRESSLER S. , MASSELINK W. T. , GOIRAN M. , RYLKOV V. V. , GALIBERT J. , LÉOTIN J.
Published: May 2007

We investigate the properties of quasi-two-dimensional electrons in AlP quantum wells by measuring cyclotron resonance, quantum Hall effect, and Shubnikov de Haas oscillations in modulation-doped AlP - GaP type-II quantum wells. We find that in wide AlP wells, the lowest conduction band states are in the Xx and Xy valleys transverse to the growth direction, that the valley degeneracy of this state is gv=2, and that the cyclotron effective mass [Formula: see text]. These results indicate that the biaxial compressive strain resulting from the lattice mismatch of AlP quantum well with respect to the GaP substrate and barrier layers causes the longitudinal Xz valley to be lifted above the transverse Xx and Xy valleys. Further, the two-fold degeneracy of the Xx and Xy valleys indicates that the conduction band minimum in AlP is located exactly at the X-point of the Brillouin zone.
A GALLERY OF CHUA ATTRACTORS: PART III
Authors: BILOTTA ELEONORA , STRANGES FAUSTO , PANTANO PIETRO
Published: May 2007

The visualization of patterns related to chaos is a challenge for those who are part of today's dynamical systems community, especially when we consider the aim of providing users with the ability to visually analyze and explore large, complex datasets related to chaos. Thus visualization could be considered a useful element in the discovery of unexpected relationships and dependencies that may exist inside the domain of chaos, both in the phase and the parameter spaces. In the second part of "A Gallery of Chua attractors", we presented an overview of forms which can only be produced by the physical circuit. In Part III, we illustrate the variety and beauty of the strange attractors produced by the dimensionless version of the system. As in our earlier work, we have used ad hoc methods, such as bifurcation maps and software tools, allowing rapid exploration of parameter space. Applying these techniques, we show how it is possible, starting from attractors described in the literature, to find new families of patterns, with a special focus on the cognitive side of information seeking and on qualitative processes of change in chaos, thus demonstrating that traditional categories of chaos exploration need to be renewed.

After a brief introduction to dimensionless equations for Chua's oscillator, we show 150 attractors, which we represent using three-dimensional images, time series and FFT diagrams. For the most important patterns, we also report Lyapunov exponents. To show the position of dimensionless attractors in parameter space, we use parallel coordinate techniques that facilitate the visualization of high dimensional spaces. We use Principal Components Analysis (PCA) and Mahalanobis Distance to provide additional tools for the exploration and visualization of the structure of the parameter space.
SYNCHRONIZATION AND DESYNCHRONIZATION IN A DELAYED DISCRETE NEURAL NETWORK
Authors: PENG MINGSHU , YUAN YUAN
Published: May 2007

In this paper, we consider a delayed discrete neural network of two identical neurons with excitory interactions. After investigating the stability of the given system, we establish a new scheme, and use the scheme to analyze the possible bifurcations occurring in the model. The process from its stable equilibrium to its multiple periodic patterns is explored clearly. A clarification for the asymptotically synchronous/asynchronous regions of such a system with ℤ2 symmetry is included.
COMPUTING TWO-DIMENSIONAL GLOBAL INVARIANT MANIFOLDS IN SLOW–FAST SYSTEMS
Authors: ENGLAND J. P. , KRAUSKOPF B. , OSINGA H. M.
Published: May 2007

We present the GLOBALIZEBVP algorithm for the computation of two-dimensional stable and unstable manifolds of a vector field. Specifically, we use the collocation routines of AUTO to solve boundary problems that are used during the computation to find the next approximate geodesic level set on the manifold. The resulting implementation is numerically very stable and well suited for systems with multiple time scales. This is illustrated with the test-case examples of the Lorenz and Chua systems, and with a slow–fast model of a somatotroph cell.
SECURE TROPOS: A SECURITY-ORIENTED EXTENSION OF THE TROPOS METHODOLOGY
Authors: MOURATIDIS HARALAMBOS , GIORGINI PAOLO
Published: May 2007

Although security plays an important role in the development of multiagent systems, a careful analysis of software development processes shows that the definition of security requirements is, usually considered after the design of the system. One of the reasons is the fact that agent oriented software engineering methodologies have not integrated security concerns throughout their developing stages. The integration of security concerns during the whole range of the development stages can help in the development of more secure multiagent systems. In this paper we introduce extensions to the Tropos methodology to enable it to model security concerns throughout the whole development process. A description of the new concepts and modelling activities is given together with a discussion on how these concepts and modelling activities are integrated to the current stages of Tropos. A real life case study from the health and social care sector is used to illustrate the approach.
d-Lactic acid-induced neurotoxicity in a calf model
Authors: Abeysekara Saman , Naylor Jonathan M. , Wassef Andrew W. A. , Isak Ulyana , Zello Gordon A.
Published: May 2007

-Lactic acidosis (DAC) occurs as a complication of short-bowel syndrome in humans and in a variety of other gastrointestinal disorders in monogastrics and ruminants. DAC is associated with signs of impaired central nervous system (CNS) function including ataxia and coma. The objective of this experiment was to determine whether either acidification of nervous tissue or d-lactic acid is responsible for decreased neurological function. Eight Holstein calves (32 ± 11 days, 70 ± 10 kg) were surgically catheterized with indwelling intravenous jugular and atlanto-occipital space cerebrospinal fluid (CSF) catheters and infused for 6 h in random order with isomolar dl-lactic acid (dl-LA), l-lactic acid (l-LA), hydrochloric acid (HCl), or saline. dl-LA induced ataxia after 4 h of infusion and produced the greatest obtunding of CNS function (at 7 h, score 8.0 ± 0.4), whereas the other infusions caused neither ataxia nor scores over 1.5 ( P < 0.01 from dl-LA). dl-LA induced significantly less acidemia than HCl (at 6 h pH 7.13 ± 0.06 and 7.00 ± 0.04, base excess −16 ± 1 and −23 ± 3 mmol/l, bicarbonate 11 ± 1 and 8 ± 1 mmol/l respectively, all P < 0.01) but greater than l-LA and saline ( P < 0.01). CSF changes followed a similar but less pronounced pattern. Although HCl infusion produced a severe acidemia and CSF acidosis, only minor effects on neurological function were evident suggesting that d-lactate has a direct neurotoxic effect that is independent of acidosis. Conversely, l-LA produced only minor neurological changes.
The Reliability of Nipple Aspirate and Ductal Lavage in Women at Increased Risk for Breast Cancer—a Potential Tool for Breast Cancer Risk Assessment and Biomarker Evaluation
Authors: Visvanathan K. , Santor D. , Ali S.Z. , Brewster A. , Arnold A. , Armstrong D.K. , Davidson N.E. , Helzlsouer K.J.
Published: May 2007

Purpose: Ductal lavage, a technique used to sample epithelial cells from breast ducts, has potential use in risk assessment and biomarker evaluation among women at increased risk for breast cancer. However, little is known about the reliability of the procedure.

Methods: We evaluated the reliability of nipple aspirate (NAF) and ductal lavage at two time points 6 months apart in women at increased risk for breast cancer. Eligible women had a 5-year Gail risk ≥1.66% or lifetime risk of >20%, and/or a family history or personal history of breast cancer. All ducts that produced NAF were cannulated. The κ statistic was used to evaluate reliability of NAF production, cellular yield, and cytologic diagnosis.

Results: Sixty-nine women (mean age, 47 years) were enrolled over 35 months. Forty-seven returned for a second visit. At baseline, 65% of premenopausal and 41% of postmenopausal women produced NAF (P = 0.05), of which 72% underwent successful lavage of at least one duct. Samples of inadequate cellular material for diagnosis were significantly more likely in postmenopausal women than in premenopausal women (P = 0.04). Of the women who returned for a second visit, 18 of 24 who produced NAF had at least one duct successfully cannulated. Twenty-four ducts in 14 women were lavaged twice. Among these ducts, cellular yield for the two time points was inconsistent (κ = 0.33 ± 0.13), and only fair cytologic agreement was observed (κ = 0.32 ± 0.15). Ductal lavage was associated with moderate discomfort.

Conclusion: Currently, the use of ductal lavage is limited by technical challenges in duct cannulation, inconsistent NAF production, a high rate of inadequate cellular material for diagnosis, fair cytologic reproducibility, and low participant return rates. (Cancer Epidemiol Biomarkers Prev 2007;16(5):950–55)
Building a United Front: Aligning the Agendas for Tobacco Control, Lung Cancer Research, and Policy
Authors: Gritz Ellen R. , Sarna Linda , Dresler Carolyn , Healton Cheryl G.
Published: May 2007

Our society bears a tremendous public health burden from tobacco-related disability and death, particularly in the realm of cancer. Yet research in lung cancer and other tobacco-related diseases research is dramatically underfunded when compared to the number of people affected. Persuading policy makers to increase funding for tobacco-related research, treatment, and policy initiatives will require considerable cooperation among the researchers, clinicians, and advocates who focus on tobacco control and those who concentrate on tobacco-related disease. Traditionally, these groups have battled over resources, expending precious energy competing for scarce funding. We propose a new way forward: these forces should come together in support of a common agenda that includes both increased tobacco control efforts and additional funding for disease-related research and treatment. Speaking with a unified voice in support of a full continuum of tobacco-related policy initiatives would significantly increase the size and influence of the coalition working to address this public health epidemic. Working together offers our nation the best chance of significantly reducing the scourge of disease and death caused by tobacco use. (Cancer Epidemiol Biomarkers Prev 2007;16(5):859–63)
Can Modulation of Mammary Gland Development by Dietary Factors Support Breast Cancer Prevention?
Authors: Wärri Anni M. , Saarinen Niina M. , Mäkelä Sari I.
Published: May 2007

Breast cancer continues to be a major challenge for public health, since it is the most common cancer of women in the Western world, and its prevalence is still increasing. In order to achieve better results in the prevention and treatment of breast cancer it is crucial to identify the mechanisms behind its initiation, i.e. the changes and deviations that have occurred in the mammary gland growth. It has long been known that a woman’s reproductive history is the strongest breast cancer risk factor if genetic background and age are excluded. The reproductive hormones, and the timing of events leading to changes in these hormones, and consequently, in the mammary gland, are the most important players. However, it has become obvious that dietary components may also contribute to breast cancer risk through their effects on the mammary gland. The past few years have added important information to our knowledge of the mechanisms behind breast cancer initiation at the level of target cells (mammary stem cells) and gene expression (genetic ‘fingerprint’ associated with persistent pregnancy-induced protection against breast cancer), as well as of the effects of certain dietary factors (steroid action modulators). These results and their links to breast cancer initiation and progression will be discussed.
Postural Sway during Dual Tasks in Young and Elderly Adults
Authors: Prado Janina M. , Stoffregen Thomas A. , Duarte Marcos
Published: May 2007

Background: Previous studies have shown that healthy young adults are able to decrease their standing postural sway when an additional postural visual task, such as reading, is performed. Objective: In this study, we investigated postural sway during dual tasks in young and elderly adults. Methods: Twelve healthy active elderly adults (aged 65–75 years) and 12 healthy young adults (aged 22–39 years) participated in the study. The subjects performed different visual tasks while standing on a force plate. We varied the nature of the visual tasks (looking at a blank target versus a visual search task) and the distance of visual targets (near versus far). Center of pressure displacement obtained from the force plate data and kinematics of body segments obtained from a video analysis system were investigated. Results: Both groups presented significantly larger postural sway in the mediolateral direction during the eyes-closed condition as compared with the eyes-open condition. In the anteroposterior direction, this effect was observed only for the elderly group. Both groups had the same percentage correct in counting letters, but the elderly adults were significantly slower as compared with the young adults. The amplitude of postural sway was greater for the elderly adults than for the young adults in all conditions. However, both the young and the elderly adults exhibited significant reductions in sway during performance of the search task relative to sway during viewing of a blank target. The sway was also reduced for both groups during viewing a near target when compared to a distant target. Conclusions: The results suggest that, despite the overall increase in postural sway with aging, subtle integration of visual information by the postural control system is not affected by aging. The present results support the idea that dual tasks do not necessarily lead to an increase in postural sway. This effect, found here in elderly adults, raises questions about widely held views in which age-related changes in postural sway are related to competition between postural control and other activities for central processing resources.