bluuebunny/crossref_metadata_2025 huggingface dataset:
Damping of Heat Exchanger Tubes in Two-Phase Flow: Review and Design Guidelines
Authors: Pettigrew M. J. , Taylor C. E.
Published: December 2004

Two-phase flow exists in many shell-and-tube heat exchangers such as condensers, evaporators, and nuclear steam generators. Some knowledge on tube damping mechanisms is required to avoid flow-induced vibration problems. This paper outlines the development of a semi-empirical model to formulate damping of heat exchanger tube bundles in two-phase cross flow. The formulation is based on information available in the literature and on the results of recently completed experiments. The compilation of a database and the formulation of a design guideline are outlined in this paper. The effects of several parameters such as flow velocity, void fraction, confinement, flow regime and fluid properties are discussed. These parameters are taken into consideration in the formulation of a practical design guideline.
Prediction of Failure Behavior for Nuclear Piping Using Curved Wide-Plate Test
Authors: Huh Nam-Su , Kim Yun-Jae , Choi Jae-Boong , Kim Young-Jin , Pyo Chang-Ryul
Published: December 2004

One important element of the Leak-Before-Break analysis of nuclear piping is how to determine relevant fracture toughness (or the J-resistance curve) for nonlinear fracture mechanics analysis. The practice to use fracture toughness from a standard C(T) specimen is known to often give conservative estimates of toughness. To improve the accuracy of predicting piping failure, this paper proposes a new method to determine fracture toughness using a nonstandard testing specimen, curved wide-plate in tension. To show validity of the proposed curved wide-plate test, the J-resistance curve from the full-scale pipe test is compared with that from the curved wide-plate test and that from C(T) specimen. It is shown that the J-resistance curve from the curved wide-plate tension test is similar to, but that from the C(T) specimen is lower than, the J-resistance curve from the full-scale pipe test. Further validation is performed by investigating crack-tip constraint conditions via detailed three-dimensional finite element analyses, which shows that the crack-tip constraint condition in the curved wide-plate tension specimen is indeed similar to that in the full-scale pipe under bending.
Design Criterion of Fatigue Analysis on Plastic Basis by ASME Boiler and Pressure Vessel Code
Authors: Kalnins Arturs , Dowling Norman E.
Published: December 2004

The paper investigates the current rules for fatigue analysis on plastic basis of the ASME Boiler and Pressure Vessel Code. It addresses the question: When these rules are used for a vessel or component, is it designed with respect to crack initiation or failure? Using available fatigue test data, the question is answered for blunt double-notch plate specimens made of AISI 4340 steel. When the rules are applied to these specimens, it is found that they are designed with respect to the initiation of a crack of a certain length that decreases as the strain range increases. The plate specimens are not designed with respect to failure. It is concluded that for geometries that exhibit a strain range gradient away from the surface, the number of cycles allowed by the current rules includes the initiation phase but not the propagation phase of a fatigue crack. If this result is unsatisfactory, new rules have to be written.
Characterization of the Novel
Fusobacterium nucleatum
Plasmid pKH9 and Evidence of an Addiction System
Authors: Bachrach Gilad , Haake Susan Kinder , Glick Alon , Hazan Ronen , Naor Ronit , Andersen Roxanna N. , Kolenbrander Paul E.
Published: December 2004

Fusobacterium nucleatum
is an important oral anaerobic pathogen involved in periodontal and systemic infections. Studies of the molecular mechanisms involved in fusobacterial virulence and adhesion have been limited by lack of systems for efficient genetic manipulation. Plasmids were isolated from eight strains of
F. nucleatum
. The smallest plasmid, pKH9 (4,975 bp), was characterized and used to create new vectors for fusobacterial genetic manipulation. DNA sequence analysis of pKH9 revealed an open reading frame (ORF) encoding a putative autonomous rolling circle replication protein (Rep), an ORF predicted to encode a protein homologous to members of the FtsK/SpoIIIE cell division-DNA segregation protein family, and an operon encoding a putative toxin-antitoxin plasmid addiction system (
txf-axf
). Deletion analysis localized the pKH9 replication region in a 0.96-kbp fragment. The pKH9
rep
gene is not present in this fragment, suggesting that pKH9 can replicate in fusobacteria independently of the Rep protein. A pKH9-based, compact
Escherichia coli-F. nucleatum
shuttle plasmid was constructed and found to be compatible with a previously described pFN1-based fusobacterial shuttle plasmid. Deletion of the pKH9 putative addiction system (
txf-axf
) reduced plasmid stability in fusobacteria, indicating its addiction properties and suggesting it to be the first plasmid addiction system described for fusobacteria. pKH9, its genetic elements, and its shuttle plasmid derivatives can serve as useful tools for investigating fusobacterial properties important in biofilm ecology and pathogenesis.
Protocol for Specific Isolation of Virulent Strains of
Vibrio vulnificus
Serovar E (Biotype 2) from Environmental Samples
Authors: Sanjuán Eva , Amaro Carmen
Published: December 2004

The eel pathogen
Vibrio vulnificus
biotype 2 comprises at least three serovars, with serovar E being the only one involved in both epizootics of eel vibriosis and sporadic cases of human infections. The virulent strains of this serovar (VSE) have only been recovered from clinical (mainly eel tissue) sources. The main objective of this work was to design and validate a new protocol for VSE-specific isolation from environmental samples. The key element of the new protocol is the broth used for the first step (saline eel serum broth [SEB]), which contains eel serum as a nutritive and selective component. This approach takes advantage of the ability of VSE cells to grow in eel serum and thus to separate themselves from the pool of competitors. The growth yield in SEB after 8 h of incubation was 1,000 times higher for VSE strains than for their putative competitors (including biotype 1 strains of the species). The selective and differential agar
Vibrio vulnificus
medium (VVM) was selected from five selective media for the second step because it gave the highest plating efficiency not only for the VSE group but also for other
V. vulnificus
groups, including biotype 3. The entire protocol was validated by field studies, with alkaline peptone water plus VVM as a control.
V. vulnificus
was isolated by both protocols, but serovar E was only recovered by the new method described here. All selected serovar E isolates were identified as VSE since they were virulent for both eels and iron-overloaded mice and resisted the bactericidal action of eel and iron-overloaded human sera. In conclusion, this new protocol is a suitable method for the isolation of VSE strains from environmental samples and is recommended for epidemiological studies of the pathogenic serovar E.
Synthesis of Novel Lipids in
Saccharomyces cerevisiae
by Heterologous Expression of an Unspecific Bacterial Acyltransferase
Authors: Kalscheuer Rainer , Luftmann Heinrich , Steinbüchel Alexander
Published: December 2004

The bifunctional wax ester synthase/acyl-coenzyme A:diacylglycerol acyltransferase (WS/DGAT) is the key enzyme in storage lipid accumulation in the gram-negative bacterium
Acinetobacter calcoaceticus
ADP1, mediating wax ester, and to a lesser extent, triacylglycerol (TAG) biosynthesis.
Saccharomyces cerevisiae
accumulates TAGs and steryl esters as storage lipids. Four genes encoding a DGAT (Dga1p), a phospholipid:diacylglycerol acyltransferase (Lro1p) and two acyl-coenzyme A:sterol acyltransferases (ASATs) (Are1p and Are2p) are involved in the final esterification steps in TAG and steryl ester biosynthesis in this yeast. In the quadruple mutant strain
S. cerevisiae
H1246, the disruption of
DGA1
,
LRO1
,
ARE1
, and
ARE2
leads to an inability to synthesize storage lipids. Heterologous expression of WS/DGAT from
A. calcoaceticus
ADP1 in
S. cerevisiae
H1246 restored TAG but not steryl ester biosynthesis, although high levels of ASAT activity could be demonstrated for WS/DGAT expressed in
Escherichia coli
XL1-Blue in radiometric in vitro assays with cholesterol and ergosterol as substrates. In addition to TAG synthesis, heterologous expression of WS/DGAT in
S. cerevisiae
H1246 resulted also in the accumulation of fatty acid ethyl esters as well as fatty acid isoamyl esters. In vitro studies confirmed that WS/DGAT is capable of utilizing a broad range of alcohols as substrates comprising long-chain fatty alcohols like hexadecanol as well as short-chain alcohols like ethanol or isoamyl alcohol. This study demonstrated the highly unspecific acyltransferase activity of WS/DGAT from
A. calcoaceticus
ADP1, indicating the broad biocatalytic potential of this enzyme for biotechnological production of a large variety of lipids in vivo in prokaryotic as well as eukaryotic expression hosts.
Allelic Diversity and Population Structure inOenococcus oenias Determined from Sequence Analysis of Housekeeping Genes
Authors: de las Rivas Blanca , Marcobal Ángela , Muñoz Rosario
Published: December 2004

Oenococcus oeniis the organism of choice for promoting malolactic fermentation in wine. The population biology ofO. oeniis poorly understood and remains unclear. For a better understanding of the mode of genetic variation within this species, we investigated by using multilocus sequence typing (MLST) with thegyrB,pgm,ddl,recP, andmleAgenes the genetic diversity and genetic relationships among 18O. oenistrains isolated in various years from wines of the United States, France, Germany, Spain, and Italy. These strains have also been characterized by ribotyping and restriction fragment length polymorphism (RFLP) analysis of the PCR-amplified 16S-23S rRNA gene intergenic spacer region (ISR). Ribotyping grouped the strains into two groups; however, the RFLP analysis of the ISRs showed no differences in the strains analyzed. In contrast, MLST in oenococci had a good discriminatory ability, and we have found a higher genetic diversity than indicated by ribotyping analysis. All sequence types were represented by a single strain, and all the strains could be distinguished from each other because they had unique combinations of alleles. Strains assumed to be identical showed the same sequence type. Phylogenetic analyses indicated a panmictic population structure inO. oeni. Sequences were analyzed for evidence of recombination by split decomposition analysis and analysis of clustered polymorphisms. All results indicated that recombination plays a major role in creating the genetic heterogeneity ofO. oeni. A low standardized index of association value indicated that theO. oenigenes analyzed are close to linkage equilibrium. This study constitutes the first step in the development of an MLST method forO. oeniand the first example of the application of MLST to a nonpathogenic food production bacteria.
Characterization of a Novel Amylolytic Enzyme Encoded by a Gene from a Soil-Derived Metagenomic Library
Authors: Yun Jiae , Kang Seowon , Park Sulhee , Yoon Hyunjin , Kim Myo-Jeong , Heu Sunggi , Ryu Sangyeol
Published: December 2004

It has been estimated that less than 1% of the microorganisms in nature can be cultivated by conventional techniques. Thus, the classical approach of isolating enzymes from pure cultures allows the analysis of only a subset of the total naturally occurring microbiota in environmental samples enriched in microorganisms. To isolate useful microbial enzymes from uncultured soil microorganisms, a metagenome was isolated from soil samples, and a metagenomic library was constructed by using the pUC19 vector. The library was screened for amylase activity, and one clone from among approximately 30,000 recombinant
Escherichia coli
clones showed amylase activity. Sequencing of the clone revealed a novel amylolytic enzyme expressed from a novel gene. The putative amylase gene (
amyM
) was overexpressed and purified for characterization. Optimal conditions for the enzyme activity of the AmyM protein were 42°C and pH 9.0; Ca
2+
stabilized the activity. The amylase hydrolyzed soluble starch and cyclodextrins to produce high levels of maltose and hydrolyzed pullulan to panose. The enzyme showed a high transglycosylation activity, making α-(1, 4) linkages exclusively. The hydrolysis and transglycosylation properties of AmyM suggest that it has novel characteristics and can be regarded as an intermediate type of maltogenic amylase, α-amylase, and 4-α-glucanotransferase.
Molecular and Genetic Characterization of Propionicin F, a Bacteriocin fromPropionibacterium freudenreichii
Authors: Brede Dag Anders , Faye Therese , Johnsborg Ola , Ødegård Inger , Nes Ingolf F. , Holo Helge
Published: December 2004

This work describes the purification and characterization of propionicin F, the first bacteriocin isolated fromPropionibacterium freudenreichii. The bacteriocin has a bactericidal activity and is only active against strains ofP. freudenreichii. Propionicin F appears to be formed through a processing pathway new to bacteriocins. The mass of the purified bacteriocin was determined by mass spectrometry, and the N-terminal amino acid sequence was determined by Edman degradation. Sequencing ofpcfA, the bacteriocin structural gene, revealed that propionicin F corresponds to a 43-amino-acid peptide in the central part of a 255-amino-acid open reading frame, suggesting that mature propionicin F is excised from the probacteriocin by N- and C-terminal proteolytic modifications. DNA sequencing and Northern blot hybridizations revealed thatpcfAis cotranscribed with genes encoding a putative proline peptidase and a protein from the radicalS-adenosylmethionine family. A gene encoding an ABC transporter was also identified in close proximity to the bacteriocin structural gene. The potential role of these genes in propionicin F maturation and secretion is discussed.
In Vivo
31
P Nuclear Magnetic Resonance Investigation of Tellurite Toxicity in
Escherichia coli
Authors: Lohmeier-Vogel Elke M. , Ung Shiela , Turner Raymond J.
Published: December 2004

Here we compare the physiological state of
Escherichia coli
exposed to tellurite or selenite by using the noninvasive technique of phosphorus-31 nuclear magnetic resonance (NMR) spectroscopy. We studied glucose-fed
Escherichia coli
HB101 cells containing either a normal pUC8 plasmid with no tellurite resistance determinants present or the pTWT100 plasmid which contains the resistance determinants
tehAB
. No differences could be observed in intracellular ATP levels, the presence or absence of a transmembrane pH gradient, or the levels of phosphorylated glycolytic intermediates when resistant cells were studied by
31
P NMR in the presence or absence of tellurite. In the sensitive strain, we observed that the transmembrane pH gradient was dissipated and intracellular ATP levels were rapidly depleted upon exposure to tellurite. Only the level of phosphorylated glycolytic intermediates remained the same as observed with resistant cells. Upon exposure to selenite, no differences could be observed by
31
P NMR between resistant and sensitive strains, suggesting that the routes for selenite and tellurite reduction within the cells differ significantly, since only tellurite is able to collapse the transmembrane pH gradient and lower ATP levels in sensitive cells. The presence of the resistance determinant
tehAB
, by an as yet unidentified detoxification event, protects the cells from uncoupling by tellurite.
Milk Contamination and Resistance to Processing Conditions Determine the Fate of
Lactococcus lactis
Bacteriophages in Dairies
Authors: Madera Carmen , Monjardín Cristina , Suárez Juan E.
Published: December 2004

Milk contamination by phages, the susceptibility of the phages to pasteurization, and the high levels of resistance to phage infection of starter strains condition the evolution dynamics of phage populations in dairy environments. Approximately 10% (83 of 900) of raw milk samples contained phages of the quasi-species c2 (72%), 936 (24%), and P335 (4%). However, 936 phages were isolated from 20 of 24 (85%) whey samples, while c2 was detected in only one (4%) of these samples. This switch may have been due to the higher susceptibility of c2 to pasteurization (936-like phages were found to be approximately 35 times more resistant than c2 strains to treatment of contaminated milk in a plate heat exchanger at 72°C for 15 s). The restriction patterns of 936-like phages isolated from milk and whey were different, indicating that survival to pasteurization does not result in direct contamination of the dairy environment. The main alternative source of phages (commercial bacterial starters) does not appear to significantly contribute to phage contamination. Twenty-four strains isolated from nine starter formulations were generally resistant to phage infection, and very small progeny were generated upon induction of the lytic cycle of resident prophages. Thus, we postulate that a continuous supply of contaminated milk, followed by pasteurization, creates a factory environment rich in diverse 936 phage strains. This equilibrium would be broken if a particular starter strain turned out to be susceptible to infection by one of these 936-like phages, which, as a consequence, became prevalent.
Integral Strategy for Evaluation of Fecal Indicator Performance in Bird-Influenced Saline Inland Waters
Authors: Kirschner Alexander K. T. , Zechmeister Thomas C. , Kavka Gerhard G. , Beiwl Christian , Herzig Alois , Mach Robert L. , Farnleitner Andreas H.
Published: December 2004

Wild birds are an important nonpoint source of fecal contamination of surface waters, but their contribution to fecal pollution is mostly difficult to estimate. Thus, to evaluate the relation between feces production and input of fecal indicator bacteria (FIB) into aquatic environments by wild waterfowl, we introduced a new holistic approach for evaluating the performance of FIB in six shallow saline habitats. For this, we monitored bird abundance, fecal pellet production, and the abundance of FIB concomitantly with a set of environmental variables over a 9-month period. For estimating fecal pellet production, a new protocol of fecal pellet counting was introduced, which was called fecal taxation (FTX). We could show that, over the whole range of investigated habitats, bird abundance, FTX values, and FIB abundance were highly significantly correlated and could demonstrate the good applicability of the FTX as a meaningful surrogate parameter for recent bird abundances and fecal contamination by birds in shallow aquatic ecosystems. Presumptive enterococci (ENT) were an excellent surrogate parameter of recent fecal contamination in these saline environments for samples collected at biweekly to monthly sampling intervals while presumptive
Escherichia coli
and fecal coliforms (FC) were often undetectable. Significant negative correlations with salinity indicated that
E. coli
and FC survival was hampered by osmotic stress. Statistical analyses further revealed that fecal pollution-associated parameters represented one system component independent from other environmental variables and that, besides feces production, rainfall, total suspended solids (direct), and trophy (indirect) had significant positive effects on ENT concentrations. Our holistic approach of linking bird abundance, feces production, and FIB detection with environmental variables may serve as a powerful model for application to other aquatic ecosystems.
Detection of Pathogenic
Vibrio
spp. in Shellfish by Using Multiplex PCR and DNA Microarrays
Authors: Panicker Gitika , Call Douglas R. , Krug Melissa J. , Bej Asim K.
Published: December 2004

This study describes the development of a gene-specific DNA microarray coupled with multiplex PCR for the comprehensive detection of pathogenic vibrios that are natural inhabitants of warm coastal waters and shellfish. Multiplex PCR with
vvh
and
viuB
for
Vibrio vulnificus
, with
ompU
,
toxR
,
tcpI
, and
hlyA
for
V. cholerae
, and with
tlh
,
tdh
,
trh
, and open reading frame 8 for
V. parahaemolyticus
helped to ensure that total and pathogenic strains, including subtypes of the three
Vibrio
spp., could be detected and discriminated. For DNA microarrays, oligonucleotide probes for these targeted genes were deposited onto epoxysilane-derivatized, 12-well, Teflon-masked slides by using a MicroGrid II arrayer. Amplified PCR products were hybridized to arrays at 50°C and detected by using tyramide signal amplification with Alexa Fluor 546 fluorescent dye. Slides were imaged by using an arrayWoRx scanner. The detection sensitivity for pure cultures without enrichment was 10
2
to 10
3
CFU/ml, and the specificity was 100%. However, 5 h of sample enrichment followed by DNA extraction with Instagene matrix and multiplex PCR with microarray hybridization resulted in the detection of 1 CFU in 1 g of oyster tissue homogenate. Thus, enrichment of the bacterial pathogens permitted higher sensitivity in compliance with the Interstate Shellfish Sanitation Conference guideline. Application of the DNA microarray methodology to natural oysters revealed the presence of
V. vulnificus
(100%) and
V. parahaemolyticus
(83%). However,
V. cholerae
was not detected in natural oysters. An assay involving a combination of multiplex PCR and DNA microarray hybridization would help to ensure rapid and accurate detection of pathogenic vibrios in shellfish, thereby improving the microbiological safety of shellfish for consumers.
Construction and Characterization of a Highly Efficient
Francisella
Shuttle Plasmid
Authors: Maier Tamara M. , Havig Andrea , Casey Monika , Nano Francis E. , Frank Dara W. , Zahrt Thomas C.
Published: December 2004

Francisella tularensis
is a facultative intracellular pathogen that infects a wide variety of mammals and causes tularemia in humans. It is recognized as a potential agent of bioterrorism due to its low infectious dose and multiple routes of transmission. To date, genetic manipulation in
Francisella
spp. has been limited due to the inefficiency of DNA transformation, the relative lack of useful selective markers, and the lack of stably replicating plasmids. Therefore, the goal of this study was to develop an enhanced shuttle plasmid that could be utilized for a variety of genetic procedures in both
Francisella
and
Escherichia coli
. A hybrid plasmid, pFNLTP1, was isolated that was transformed by electroporation at frequencies of >1 × 10
7
CFU μg of DNA
−1
in
F. tularensis
LVS,
Francisella novicida
U112, and
E. coli
DH5α. Furthermore, this plasmid was stably maintained in
F. tularensis
LVS after passage in the absence of antibiotic selection in vitro and after 3 days of growth in J774A.1 macrophages. Importantly,
F. tularensis
LVS derivatives carrying pFNLTP1 were unaltered in their growth characteristics in laboratory medium and macrophages compared to wild-type LVS. We also constructed derivatives of pFNLTP1 containing expanded multiple cloning sites or temperature-sensitive mutations that failed to allow plasmid replication in
F. tularensis
LVS at the nonpermissive temperature. In addition, the utility of pFNLTP1 as a vehicle for gene expression, as well as complementation, was demonstrated. In summary, we describe construction of a
Francisella
shuttle plasmid that is transformed at high efficiency, is stably maintained, and does not alter the growth of
Francisella
in macrophages. This new tool should significantly enhance genetic manipulation and characterization of
F. tularensis
and other
Francisella
biotypes.
Genotypes of
Cryptosporidium
Species Infecting Fur-Bearing Mammals Differ from Those of Species Infecting Humans
Authors: Zhou Ling , Fayer Ronald , Trout James M. , Ryan Una M. , Schaefer Frank W. , Xiao Lihua
Published: December 2004

Of 471 specimens examined from foxes, raccoons, muskrats, otters, and beavers living in wetlands adjacent to the Chesapeake Bay, 36 were positive for five types of
Cryptosporidium
, including the
C. canis
dog and fox genotypes,
Cryptosporidium
muskrat genotypes I and II, and
Cryptosporidium
skunk genotype. Thus, fur-bearing mammals in watersheds excreted host-adapted
Cryptosporidium
oocysts that are not known to be of significant public health importance.
Is there an Aboriginal bioethic?
Authors: Garvey G , Towney P , McPhee J R , Little M , Kerridge I H
Published: December 2004

It is well recognised that medicine manifests social and cultural values and that the institution of healthcare cannot be structurally disengaged from the sociopolitical processes that create such values. As with many other indigenous peoples, Aboriginal Australians have a lower heath status than the rest of the community and frequently experience the effects of prejudice and racism in many aspects of their lives. In this paper the authors highlight values and ethical convictions that may be held by Aboriginal peoples in order to explore how health practitioners can engage Aboriginal patients in a manner that is more appropriate. In doing so the authors consider how the ethics, values, and beliefs of the dominant white Australian culture have framed the treatment and delivery of services that Aboriginal people receive, and whether sufficient effort has been made to understand or acknowledge the different ethical predispositions that form the traditions and identity of Aboriginal Australia(ns).
The battering of informed consent
Authors: Kottow M
Published: December 2004

Autonomy has been hailed as the foremost principle of bioethics, and yet patients’ decisions and research subjects’ voluntary participation are being subjected to frequent restrictions. It has been argued that patient care is best served by a limited form of paternalism because the doctor is better qualified to take critical decisions than the patient, who is distracted by illness. The revival of paternalism is unwarranted on two grounds: firstly, because prejudging that the sick are not fully autonomous is a biased and unsubstantial view; secondly, because the technical knowledge of healthcare professionals does not include the ethical qualifications and prerogative to decide for others.

Clinical research settings are even more prone to erode subjects’ autonomy than clinical settings because of the tendency and temptation to resort to such practices as shading the truth when consent to participation is sought, or waiving consent altogether when research is done in emergency settings.

Instead of supporting such dubious practices with unconvincing arguments, it would seem to be the task of bioethics to insist on reinforcing autonomy.
Willingness to donate: an interview study before liver transplantation
Authors: Walter M , Papachristou C , Danzer G , Klapp B F , Frommer J
Published: December 2004

Objectives:The introduction of the living donation in organ transplantation introduces important new psychological conflicts and ethical questions in the transplantation process. Operation related risks, as well as dependencies in the family structure, generate considerable pressure on potential donors. The aim of the study was to reconstruct the determinants of willingness to donate before transplantation.

Methods:Evaluation of 20 taped and transcribed interviews oriented to current approaches in qualitative interview research. The approach used is based on grounded theory, qualitative content analysis, and the concept of the ideal type.

Results:Before surgery, “openly motivated” donors push for an operation, leaving no room for ambivalence in the evaluation process. They idealise the relationship with the recipient, and link their donation with the individual—partly in subconscious expectations and wishes. In contrast, “openly ambivalent” donors formulate their anxieties and express arguments against donation.

Conclusions:Statements that claim ambivalence towards donation or utterance of arguments against donation indicate earlier coercion. Before transplantation, potential donors should have the opportunity to discuss their emotional situation to help their decision making process.
EXPERIMENTAL ANALYSIS OF SOME VARIANTS OF VOGEL'S APPROXIMATION METHOD
Authors: MATHIRAJAN M. , MEENAKSHI B.
Published: December 2004

This paper presents a variant of Vogel's approximation method (VAM) for transportation problems. The importance of determining efficient solutions for large sized transportation problems is borne out by many practical problems in industries, the military, etc. With this motivation, a few variants of VAM incorporating the total opportunity cost (TOC) concept were investigated to obtain fast and efficient solutions. Computational experiments were carried out to evaluate these variants of VAM. The quality of solutions indicates that the basic version of the VAM coupled with total opportunity cost (called the VAM–TOC) yields a very efficient initial solution. In these experiments, on an average, about 20% of the time the VAM–TOC approach yielded the optimal solution and about 80% of the time it yielded a solution very close to optimal (0.5% loss of optimality). The CPU time required for the problem instances tested was very small (on an average, less than 10 s on a 200 MHz Pentium machine with 64 MB RAM).
STUDY ON UNCONVENTIONAL SUPERCONDUCTORS VIA ANGLE-RESOLVED SPECIFIC HEAT
Authors: PARK TUSON , SALAMON M. B.
Published: December 2004

The gap function in unconventional superconductors may vanish at points or lines in momentum space, permitting electronic excitations, termed "nodal quasiparticles", to exist at temperatures well below the superconducting transition. In the vortex phase, the presence of nodal quasiparticles should be directly observable through the variation of the heat capacity with the angle between a magnetic field and the location of the zeroes of the gap. The heat capacity of candidate nonmagnetic unconventional superconductors Lu ( Y ) Ni 2 B 2 C were found to exhibit fourfold oscillations with field angle, the first such observation. The observed angular variations are in quantitative agreement with theory, confirming that quasiparticles are created via Doppler shifts at nodes along <100>. Anomalous disorder effects have been also observed in the field-angle-dependent heat capacity Cp(α). In a slightly disordered sample, anomalous secondary minima along <110> appeared for μ0H>1 T , leading to an eightfold pattern. The coexistence of an anisotropic superconducting gap and nonlocal effects is shown to drive the anomalous behavior. These results demonstrate that field-angle-dependent heat capacity can be a powerful tool in probing the momentum-space gap structure in unconventional superconductors such as high-Tc cuprates, heavy fermions, borocarbides, etc.
FORCE GENERATION DUE TO FLUCTUATIONS OF MEDIA AND BOUNDARIES
Authors: GOLESTANIAN RAMIN
Published: December 2004

In a fluctuating medium, whether of quantum, thermal, or non-thermal origins, an interaction is induced between external objects that modify the fluctuations. These interactions can appear in a vast variety of systems, leading to a plethora of interesting phenomena. Notable examples of these include:

1. like-charge attraction in the presence of multivalent counterions;

2. Ludwig–Soret effect in charged colloids;

3. mass renormalization of moving defects in a phononic background and moving metallic objects in electromagnetic quantum vacuum;

4. dissipation due to motion-induced radiation.

Another related class of problems corresponds to stirring the media by dynamic deformations of the embedded bodies and benefiting from the back-reaction of the stirred media for force generation, such as force generation in swimming. The fluctuation-induced forces are statistical in nature, and this could make their measurements very difficult, because the actual value of the force might deviate most of the time from the predicted average value.
GEOMETRIC TRANSPORT ALONG CIRCULAR ORBITS IN STATIONARY AXISYMMETRIC SPACETIMES
Authors: BINI DONATO , CHERUBINI CHRISTIAN , CRUCIANI GIANLUCA , JANTZEN ROBERT T.
Published: December 2004

Parallel transport along circular orbits in orthogonally transitive stationary axisymmetric spacetimes is described explicitly relative to Lie transport in terms of the electric and magnetic parts of the induced connection. The influence of both the gravito-electromagnetic fields associated with the zero angular momentum observers and of the Frenet–Serret parameters of these orbits as a function of their angular velocity is seen on the behavior of parallel transport through its representation as a parameter-dependent Lorentz transformation between these two inner-product preserving transports which is generated by the induced connection. This extends the analysis of parallel transport in the equatorial plane of the Kerr spacetime to the entire spacetime outside the black hole horizon, and helps give an intuitive picture of how competing "central attraction forces" and centripetal accelerations contribute with gravitomagnetic effects to explain the behavior of the 4-acceleration of circular orbits in that spacetime.
CLIFFORD VALUED DIFFERENTIAL FORMS, AND SOME ISSUES IN GRAVITATION, ELECTROMAGNETISM AND "UNIFIED" THEORIES
Authors: RODRIGUES W. A. , CAPELAS DE OLIVEIRA E.
Published: December 2004

In this paper we show how to describe the general theory of a linear metric compatible connection with the theory of Clifford valued differential forms. This is done by realizing that for each spacetime point the Lie algebra of Clifford bivectors is isomorphic to the Lie algebra of [Formula: see text]. In that way the pullback of the linear connection under a local trivialization of the bundle (i.e., a choice of gauge) is represented by a Clifford valued 1-form. That observation makes it possible to realize immediately that Einstein's gravitational theory can be formulated in a way which is similar to a [Formula: see text] gauge theory. Such a theory is compared with other interesting mathematical formulations of Einstein's theory, and particularly with a supposedly "unified" field theory of gravitation and electromagnetism proposed by M. Sachs. We show that his identification of Maxwell equations within his formalism is not a valid one. Also, taking profit of the mathematical methods introduced in the paper we investigate a very polemical issue in Einstein gravitational theory, namely the problem of the 'energy–momentum' conservation. We show that many statements appearing in the literature are confusing or even wrong.
STOCHASTIC VERSIONS OF HARTMAN–GROBMAN THEOREMS
Authors: COAYLA-TERAN EDSON A. , RUFFINO PAULO R. C.
Published: December 2004

We present versions of Hartman–Grobman theorems for random dynamical systems (RDS) in the discrete case. We use the same random norm like in Wanner [14], but instead of using difference equations, we perform an appropriate generalization of the deterministic arguments in an adequate space of measurable homeomorphisms to extend the results in [14] with weaker hypotheses (integrability instead of boundedness) and simpler arguments.
QUANTIFYING PREDICTABILITY IN A SIMPLE MODEL WITH COMPLEX FEATURES
Authors: CAI DAVID , HAVEN KYLE , MAJDA ANDREW J.
Published: December 2004

Here, Kaplan–Yorke type maps are utilized as simplified models to assess new strategies for quantifying predictability through information theory. These models give rise to a wide variety of "climate" distributions from nearly Gaussian to highly non-Gaussian. For complex models, it is almost impossible to compute proposed theoretical measures of predictability directly and alternative methods of estimation must be utilized. Due to the simplicity of the proposed model, accurate approximations of predictability can be computed and compared to various estimation techniques. A recently proposed method for finding a lower bound estimate of the predictability is outlined in the context of the model. Estimates of this type are computed and evaluated for a long-term climate prediction scenario. The factors that control the predictability for this scenario are determined using an ensemble of ensembles approach. In addition, the lower bound estimates are used as a means of assessing the utility of a Gaussian approximation strategy.
SIMULATION-BASED DECISION SUPPORT FOR MANUFACTURING SYSTEM LIFE CYCLE MANAGEMENT
Authors: DE VIN LEO J. , NG AMOS H. C. , OSCARSSON JAN
Published: December 2004

Previous research has highlighted the role of virtual engineering tools in the development of manufacturing machinery systems. Simulation models created for this purpose can potentially be used to provide support for other tasks, such as operational planning and service and maintenance. This requires that the simulation models can be fed with historic data as well as with snapshot data. Furthermore, the models must be able to communicate with other business software. The paper describes how simulation models can be used for operational production planning and for service and maintenance support. Benefits include a better possibility to verify production plans and the possibility to monitor and service manufacturing machinery from remote locations. Furthermore, the expanded and continuously updated models provide a good tool to study the effect of, for instance, planned new product introduction in existing manufacturing systems. The paper also presents directions for future research. One ambition is to add AI tools to the system so as to develop a semi-autonomous system for decision support.
R&D ACTIVITIES IN KOREA ON VIRTUAL MANUFACTURING
Authors: KIM BO HYUN , CHOI BYOUNG KYU , CHOI BYUNG-WOOK
Published: December 2004

The most prominent trends in manufacturing are in terms of setting up globally distributed manufacturing facilities, a move towards mass customization, and initiatives focused on enabling reduction in time to market. Manufacturing industry responds to these trends by adopting new concepts such as Virtual Manufacturing (VM), Digital Manufacturing and an Extended Enterprise. VM, especially, plays a key role in realizing the next generation manufacturing system for the 21st century. Korean industry has introduced commercial VM solutions for constructing application examples and optimizing some parts of the business process. To review the current status of VM R&D and application activities and to make a human network for VM activity in Korea, the 1st VM Workshop was held on May 30, 2003, in Seoul. This paper introduces the major outcomes from the Workshop and discusses the future prospect of the VM activity.
A PRACTICAL FRAMEWORK TO EVALUATE AND SELECT ROBOTS FOR ASSEMBLY OPERATIONS
Authors: GHRAYEB OMAR , PHOJANAMONGKOLKIJ NIPA , MARCELLUS RICHARD , ZHAO WAYNE
Published: December 2004

In robot assembly operations, the assembly cycle time is not linearly proportional to the maximum speed of the robot. Therefore, if the decision-maker wants to select and evaluate robots with respect to a specific assembly work, it is necessary to use the assembly cycle time to replace the maximum speed as an attribute in the evaluation process. This paper presents a methodology that uses assembly cycle time as an evaluation attribute instead of using robots' maximum speed. The resulting robot ranking is more realistic because the evaluation process considers the assembly jobs under consideration. Three computational examples are presented to support this conclusion.
WAVELETS AND STATISTICAL TECHNIQUES FOR DATA ANALYSIS IN A MOCK-UP HIGH-LEVEL WASTE STORAGE EXPERIMENT
Authors: CAÑAMÓN I. , ELORZA F. J. , MANGIN A. , MARTÍN P. L. , RODRÍGUEZ R.
Published: December 2004

This work analyzes the physical processes occurring in the Mock-up test of the FEBEX I and II projects. FEBEX I and II is an European research project (1996–2004) led by ENRESA, that has financial support from the European Commission. This experiment is based in two large-scale heating tests ("in-situ" test and "Mock-up" test) simulating a radioactive waste repository, and tries to analyze the thermo-hydro-mechanical (THM) processes that could eventually happen in this kind of repositories.

The main objectives of this study have been the following: to identify the physical processes occurring in the Mock-up experiment and to characterize them quantitatively; to understand the nature and consequences of several incidents happening in the Mock-up during the heating phase; and, finally, to analyze the data reliability of the sensors measurements and to predict possible failures.

The analysis techniques used in this work are both statistical (time series correlation and spectral analysis, wavelets analysis, matching pursuit analysis) and non-statistical (spatial distribution analysis of data). These methods aim to establish the existing relationships between several data series registered in the experiment, corresponding to the measured parameters, and to characterize on time and frequency the non-stationary response of the series. A better understanding of the main THM processes affecting the engineered barriers used for the isolation of the radioactive waste is then available with the results obtained from those analyses.
ACCURATE SIGNAL ESTIMATION NEAR DISCONTINUITIES
Authors: DOWNIE T. R.
Published: December 2004

Wavelet thresholding is an effective method for noise reduction of a wide class of naturally occurring signals. However, bias near to a discontinuity and Gibbs phenomenon are a drawback in wavelet thresholding. The extent to which this is a problem is investigated. The Haar wavelet basis is good at approximating discontinuities, but is bad at approximating other signal artefacts. A method of detecting jumps in a signal is developed that uses non-decimated Haar wavelet coefficients. This is designed to be used in conjunction with most existing thresholding methods.

A detailed simulation study is carried out and results show that when discontinuities are present a substantial reduction in bias can be obtained, leading to a corresponding reduction in mean square error.
TRANSLATION INVARIANT DECONVOLUTION IN A PERIODIC SETTING
Authors: DONOHO DAVID L. , RAIMONDO MARC E.
Published: December 2004

Deconvolution of a noisy signal in a periodic band-limited wavelet basis exhibits visual artifacts in the neighbourhood of discontinuities. This phenomenon is similar to that appearing in denoising with compactly-supported wavelet transforms and can be reduced by "cycle spinning" as in Coifman and Donoho [3]. In this paper we present an algorithm which "cycle-spins" a periodic band-limited wavelet estimator over all circulant shifts in O(n( log (n))2) steps. Our approach is based on a mathematical idea and takes full advantage of the Fast Fourier Transform. A particular feature of our algorithm is to bounce from the Fourier domain (where deconvolution is performed) to the wavelet domain (where denoising is performed). For both smooth and boxcar convolutions observed in white noise, we illustrate the visual and numerical performances of our algorithm in an extensive simulation study of the [Formula: see text] estimator recently proposed by Johnstone, Kerkyacharian, Picard, and Raimondo [8]. All figures presented here are reproducible using the [Formula: see text] software package.
QUANTUM COMPUTER: AN APPLIANCE FOR PLAYING MARKET GAMES
Authors: PIOTROWSKI EDWARD W. , SŁADKOWSKI JAN
Published: December 2004

Recent developments in quantum computation and quantum information theory allow one to extend the scope of game theory for the quantum world. The authors have recently proposed a quantum description of financial market in terms of quantum game theory. This paper contains an analysis of such markets that shows that there are advantages to be gained from using quantum computers and quantum strategies.
Melatonin enhances leptin expression by rat adipocytes in the presence of insulin
Authors: Alonso-Vale Maria Isabel Cardoso , Andreotti Sandra , Peres Sidney Barnabé , Anhê Gabriel Forato , das Neves Borges-Silva Cristina , Neto José Cipolla , Lima Fabio Bessa
Published: December 2004

Leptin and melatonin play an important role in the regulation of body mass and energy balance. Both hormones show a circadian rhythm, with increasing values at night. In addition, melatonin receptors were recently described in adipocytes, where leptin is synthesized. Here, we investigated the influence of melatonin and its interaction with insulin and dexamethasone on leptin expression. Isolated rat adipocytes were incubated with melatonin (1 nM) alone or in combination with insulin (5 nM) and/or dexamethasone (7 nM) for 6 h. Melatonin or insulin alone did not affect leptin expression, but together they increased it by 120%. Dexamethasone increased leptin mRNA content (105%), and this effect was not enhanced by melatonin. Simultaneous treatment with the three hormones provoked a further increase in leptin release (250%) and leptin mRNA (100%). Melatonin prevented the forskolin-induced inhibition (95%) of leptin expression. In addition, melatonin's ability to stimulate leptin release (in the presence of insulin) was completely blocked by pertussis toxin and luzindole. To gain further insight into the molecular basis of melatonin and insulin synergism, the insulin-signaling pathway was investigated. Melatonin increased the insulin-induced insulin receptor-β tyrosine phosphorylation, which led to an increased serine phosphorylation of the downstream convergent protein Akt. We concluded that melatonin interacts with insulin and upregulates insulin-stimulated leptin expression. These effects are caused by melatonin binding to the pertussis toxin-sensitive Giprotein-coupled membrane receptor (MT1subtype) and the cross talk with insulin, since insulin receptor and its convergent target Akt are coactivated by melatonin.
CRH stimulation of corticosteroids production in melanocytes is mediated by ACTH
Authors: Slominski Andrzej , Zbytek Blazej , Szczesniewski Andrzej , Semak Igor , Kaminski Jan , Sweatman Trevor , Wortsman Jacobo
Published: December 2004

The response to systemic stress is organized along the hypothalamic-pituitary-adrenal axis (HPA), whereas the response to a peripheral stress (solar radiation) is mediated by epidermal melanocytes (cells of neural crest origin) responsible for the pigmentary reaction. Melanocytes express proopiomelanocortin (POMC), corticotropin-releasing hormone (CRH), and CRH receptor-1 (CRH-R1) and can produce corticosterone. In the present study, incubation of normal epidermal melanocytes with CRH was found to trigger a functional cascade structured hierarchically and arranged along the same algorithm as in the HPA axis: CRH activation of CRH-R1 stimulated cAMP accumulation and increased POMC gene expression and production of ACTH. CRH and ACTH also enhanced production of cortisol and corticosterone, and cortisol production was also stimulated by progesterone. The chemical identity of the cortisol was confirmed by liquid chromatography-mass spectrometry without mass spectrometry-mass spectrometry analyses. POMC gene silencing abolished the stimulatory effect of CRH on corticosteroid synthesis, indicating that this is indirect and mediated via production of ACTH. Thus the melanocyte response to CRH is highly organized along the same functional hierarchy as the HPA axis. This pattern demonstrates the fractal nature of the response to stress with similar activation sequence at the single-cell and whole body levels.