bluuebunny/crossref_metadata_2025 huggingface dataset:
A Numerical Study of the Response of Building Components to Heating in a Fire
Authors: Holve D. J. , Kanury A. M.
Published: October 2009

This paper addresses the problem of fire resistance of building systems. A numerical parametric study is performed to find the influence of various physical and chemical parameters on the thermochemical response of wood, gypsum, and wood-under-gypsum walls subjected to a simulated fire on the front face. It is found that: (i) the thermal radiation terms are important in the exposure boundary condition; (ii) the pyrolysis kinetic detail required to design fire-resistive walls is minimal; and (iii) the earlier dimensional and approximate analyses are in agreement with the present numerical results. These results suggest use of a simple analytical relationship to describe and correlate the ASTM E-119 fire endurance test data.
Effect of Laminarization and Retransition on Heat Transfer for Low Reynolds Number Flow Through a Converging to Constant Area Duct
Authors: Tanaka H. , Kawamura H. , Tateno A. , Hatamiya S.
Published: October 2009

A fully developed turbulent air flow between two parallel plates with the spacing of 15 mm was accelerated through a linearly converging passage of 200 mm in length, from which it flowed into a parallel-plate channel again. A foil heater was fastened on one wall surface over the entire channel, and local heat-transfer coefficient distribution was measured over the channel Reynolds number range of 5000 to 14,000 and also the slope of the accelerating section between 2/200 mm/mm and 10/200 mm/mm. (The acceleration parameter K ranged between 1.4 × 10−6 and 2 × 10−5.) The Nusselt number at the outlet of the accelerating section was considerably lower than in the initial fully turbulent state, suggesting laminarization of the flow. The measured Nusselt number continued to decrease in the first part of the downstream parallel-plate section to a minimum and then began to increase sharply, suggesting reversion to turbulent flow. Heat transfer along the parallel-converging-parallel plate system was reproduced fairly satisfactorily by applying a k-kL model of turbulence.
View Factors in Radiation Between Two Parallel Oriented Cylinders of Finite Lengths
Authors: Juul N. H.
Published: October 2009

A simple double-integral expression for the diffuse radiation view factor, F12, between two parallel cylinders of finite lengths is derived. No closed-form solution appears possible except for the limiting case of infinite long cylinders for which an analytical expression for the view factor F12∞ is derived by applying the crossed string method. The accuracies of the line source approximations are evaluated, and the regions for which they are accurate to one percentage or better are identified. The view factor F12 between two opposing cylinders of equal length is computed by numerical integration and normalized by F12∞. The results are presented. Analytical expressions, which approximate the view factors between two opposite cylinders of finite length, are derived and their accuracy is evaluated over a useful parameter range. The range of their applications corresponds approximately to that for the line source approximation. This result is expected, because the errors are caused in part by blockage of radiation which is similar.
Heat Convection in Annular Type Crevices
Authors: Yao Shi-chune , Hung Ying-Huei
Published: October 2009

The laminar flow and heat convection in annular type crevices of various eccentricities and inclinations are analyzed. The annulus is heated by hot flowing fluid at the inside of the inner tube. The flow field is calculated using creeping flow approximation of boundary layer theory. The thermal field is studied two-dimensionally in terms of the local bulk mean temperature of the fluid. Calculation is performed numerically but in nondimensional form. It is observed that the angle of inclination influences the flow and heat transfer significantly, especially when the eccentricity is severe. When the angle of inclination increases, the flow rate is reduced, the bulk mean temperature at the exit of crevice increases, and the averaged heat-transfer coefficient in crevice decreases. Comparisons are made with respect to the results of concentric annulus.
Corrugated-Duct Heat Transfer, Pressure Drop, and Flow Visualization
Authors: O’Brien J. E. , Sparrow E. M.
Published: October 2009

Experiments were performed to determine forced convection heat-transfer coefficients and friction factors for flow in a corrugated duct. The corrugation angle was 30 deg and the interwall spacing was equal to the corrugation height. The Reynolds number, based on the duct hydraulic diameter, ranged from 1500 to 25,000, and the Prandtl number ranged from 4 to 8 (water). Flow visualization, using the oil-lampblack technique, revealed a highly complex flow pattern, including large zones of recirculation adjacent to the rearward-facing corrugation facets. Nusselt numbers in the periodic fully developed regime, when correlated, resulted in a Reynolds-number dependence of Re0.614 and a Prandtl-number dependence of Pr0.34. The enhancement of heat transfer as compared to a conventional parallel-plate channel was about a factor of 2.5. Friction factors obtained from measured axial pressure distributions were virtually independent of the Reynolds number and equal to 0.57, a value appreciably greater than that for unidirectional duct flows.
Multidimensional Numerical Modeling of Heat Exchangers
Authors: Sha W. T. , Yang C. I. , Kao T. T. , Cho S. M.
Published: October 2009

A comprehensive, multidimensional, thermal-hydraulic model is developed for the analysis of shell-and-tube heat exchangers for liquid metal services. For the shellside fluid, the conservation equations of mass, momentum and energy for continuum fluids are modified using the concept of porosity, surface permeability and distributed resistance to account for the blockage effects due to the presence of heat transfer tubes, flow baffles/shrouds, the support plates, etc. On the tubeside, the heat transfer tubes are connected in parallel between the inlet and outlet plenums, and tubeside flow distribution is calculated based on the plenum-to-plenum pressure difference being equal for all tubes. It is assumed that the fluid remains single-phased on the shell side and may undergo phase-change on the tube side, thereby simulating the conditions of Liquid Metal Fast Breeder Reactor (LMFBR) intermediate heat exchangers (IHX) and steam generators (SG). The analytical model predictions are compared with three sets of test data (one for IHX and two for SG) and favorable results are obtained, thus providing a limited validation of the model.
Laminar Wavy-Film Flow: Part II, Condensation and Evaporation
Authors: Hirshburg R. I. , Florschuetz L. W.
Published: October 2009

The Nusselt theory for laminar film condensation or evaporation is shown to significantly underpredict existing experimental data because of the presence of waves on the liquid-vapor interface. A heat transfer model is presented which incorporates the results of a previously developed hydrodynamic wavy-film model (Part I). Results based on the model for both local and mean Nusselt numbers are shown to be consistent with available experimental data, and to satisfactorily account for the deviation of the data from the classical Nusselt theory.
The Effect of Noncondensible Gases on Bubble Condensation in an Immiscible Liquid
Authors: Jacobs H. R. , Major B. H.
Published: October 2009

A numerical study of the collapse of a bubble in a three-component, three-phase system is presented. The heat transfer is modeled using a quasi-steady integral boundary layer approach while the concentration profiles of noncondensibles are determined by solving the transient diffusion equation. It is shown that the experimentally determined collapse of small bubbles (between 1-mm and 3-mm initial radius) agrees with the model, while larger bubbles, which deform during their early history, are better described by a uniformly distributed noncondensible model.
Measurements of Natural Convection Across Tilted Rectangular Enclosures of Aspect Ratio 0.1 and 0.2
Authors: Wirtz R. A. , Righi J. , Zirilli F.
Published: October 2009

Laboratory experiments with water are reported for the range 108<RaH<5×109 where the enclosure tilt angle, φ, is varied from zero (sideways heating) to 90 deg (heating from below). Shadowgraph observations show that the flow regime studied extends from laminar at φ=0 and lower RaH, to turbulent at φ>0 and high RaH. At φ≲72 deg the convection consists of a peripheral boundary layer which closely follows the enclosure boundaries. At φ≳72 deg the flow axis rotates 90 deg. Convection consists of a single transverse roll with axis oriented upslope of the heated wall. While the average heat transfer is found to be maximum at 50 deg <φ<60 deg, its variation with φ is small. A single correlation equation may be used to predict the average Nusselt number over all angles. The correlation proposed predicts the average Nusselt number with an r.m.s. deviation of ± 10 percent.
MK-7009, a Potent and Selective Inhibitor of Hepatitis C Virus NS3/4A Protease
Authors: Liverton Nigel J. , Carroll Steven S. , DiMuzio Jillian , Fandozzi Christine , Graham Donald J. , Hazuda Daria , Holloway M. Katherine , Ludmerer Steven W. , McCauley John A. , McIntyre Charles J. , Olsen David B. , Rudd Michael T. , Stahlhut Mark , Vacca Joseph P.
Published: October 2009

The administration of hepatitis C virus (HCV) NS3/4A protease inhibitors to patients with chronic HCV infections has demonstrated that they have dramatic antiviral effects and that compounds acting via this mechanism are likely to form a key component of future anti-HCV therapy. We report here on the preclinical profile of MK-7009, an inhibitor of genotype 1a and 1b proteases at subnanomolar concentrations with modestly shifted potency against genotype 2a and 2b proteases at low nanomolar concentrations. Potent activity was also observed in a cell-based HCV replicon assay in the presence of added human serum (50%). In multiple species evaluated in preclinical studies, the MK-7009 concentrations in the liver were maintained at a significant multiple of the cell-based replicon 50% effective concentration over 12 to 24 h following the administration of moderate oral doses (5 to 10 mg per kg of body weight). MK-7009 also had excellent selectivity against both a range of human proteases and a broad panel of pharmacologically relevant ion channels, receptors, and enzymes. On the basis of this favorable profile, MK-7009 was selected for clinical development and is currently being evaluated in controlled clinical trials with both healthy volunteers and HCV-infected patients.
Pharmacokinetics of Artemether-Lumefantrine and Artesunate-Amodiaquine in Children in Kampala, Uganda
Authors: Mwesigwa Julia , Parikh Sunil , McGee Bryan , German Polina , Drysdale Troy , Kalyango Joan N. , Clark Tamara D. , Dorsey Grant , Lindegardh Niklas , Annerberg Anna , Rosenthal Philip J. , Kamya Moses R. , Aweeka Francesca
Published: October 2009

The World Health Organization recommends the use of artemisinin-based combination therapies (ACTs) for the treatment of uncomplicated malaria. The two most widely adopted ACT regimens are artemether (AR)-lumefantrine (LR) (the combination is abbreviated AL) and amodiaquine (AQ)-artesunate (AS). Pharmacokinetic (PK) data informing the optimum dosing of these drug regimens is limited, especially in children. We evaluated PK parameters in Ugandan children aged 5 to 13 years with uncomplicated malaria treated with AL (
n
= 20) or AQ-AS (
n
= 21), with intensive venous sampling occurring at 0, 2, 4, 8, 24, and 120 h following administration of the last dose of 3-day regimens of AL (twice daily) or AQ-AS (once daily). AS achieved an estimated maximum concentration in plasma (
C
max
) of 51 ng/ml and an area under the concentration-time curve from time zero to infinity (AUC
0-∞
) of 113 ng·h/ml; and its active metabolite, dihydroartemisinin (DHA), achieved a geometric mean
C
max
of 473 ng/ml and an AUC
0-∞
of 1,404 ng·h/ml. AR-DHA exhibited a
C
max
of 34/119 ng/ml and an AUC
0-∞
of 168/382 ng·h/ml, respectively. For LR,
C
max
and AUC
0-∞
were 6,757 ng/ml and 210 μg·h/ml, respectively. For AQ and its active metabolite, desethylamodiaquine (DEAQ), the
C
max
s were 5.2 ng/ml and 235 ng/ml, respectively, and the AUC
0-∞
s were 39.3 ng·h/ml and 148 μg·h/ml, respectively. Comparison of the findings of the present study to previously published data for adults suggests that the level of exposure to LR is lower in children than in adults and that the level of AQ-DEAQ exposure is similar in children and adults. For the artemisinin derivatives, differences between children and adults were variable and drug specific. The PK results generated for children must be considered to optimize the dosing strategies for these widely utilized ACT regimens.
In Vivo Activities of Recombinant Divercin V41 and Its Structural Variants against
Listeria monocytogenes
Authors: Rihakova Jitka , Cappelier Jean-Michel , Hue Isabelle , Demnerova Katerina , Fédérighi Michel , Prévost Hervé , Drider Djamel
Published: October 2009

Recombinant divercin RV41 (DvnRV41) and its structural variants were used in this study to assess their antilisterial activities in vivo in mice challenged intravenously with
Listeria monocytogenes
EGDe. Treatment with DvnRV41 before and after infection permitted a conclusion as to the capacities of this peptide to retain activity and reduce growth of
L. monocytogenes
EGDe. Moreover, the use of structural variants for the first time in vivo and the reductions of their activities confirmed the importance of certain amino acids in antilisterial activity.
Inducible APOBEC3G-Vif Double Stable Cell Line as a High-Throughput Screening Platform To Identify Antiviral Compounds
Authors: Nowotny Boris , Schneider Thomas , Pradel Gabriele , Schirmeister Tanja , Rethwilm Axel , Kirschner Marc
Published: October 2009

Inhibition of the interaction of the human cytidine-deaminase APOBEC3G (A3G) with the human immunodeficiency virus (HIV) type 1-specific viral infectivity factor (Vif) represents a novel therapeutic approach in which a cellular factor with potent antiviral activity (A3G) plays a key role. In HIV-infected cells, the interaction of Vif with A3G leads to the subsequent degradation of A3G by the 26S proteasome via the ubiquitin pathway and to the loss of antiviral activity. To establish a stable and convenient cellular testing platform for the high-throughput screening of potential antiviral compound libraries, we engineered a double transgenic cell line constitutively expressing an enhanced yellow fluorescent protein expressor (EYFP-A3G) fusion as well as a Tet-Off controllable Vif protein. With this cell line, we were able to measure precisely the Vif-induced degradation of A3G in the presence of potential antiviral compounds in an easy-to-handle, robust, and practical high-throughput multiwell plate format with an excellent screening window coefficient (
Z
factor) of 0.67.
Efficacy of Posaconazole in a Murine Disseminated Infection by
Can
dida tropicalis
Authors: Mariné Marçal , Pastor F. Javier , Guarro Josep
Published: October 2009

We evaluated the efficacy of posaconazole against
Candida tropicalis
in a systemic infection model with immunosuppressed mice. Posaconazole at 50 mg/kg of body weight/day prolonged the survival of mice and reduced the fungal tissue burden of mice infected with any of the five strains tested, with the exception of one strain that had a high MIC against this drug. Our results demonstrate the efficacy of posaconazole in the treatment of invasive murine infection caused by
C. tropicalis
.
Requirement for Formin-Induced Actin Polymerization during Spread of
Shigella flexneri
Authors: Heindl Jason E. , Saran Indrani , Yi Chae-ryun , Lesser Cammie F. , Goldberg Marcia B.
Published: October 2009

Actin polymerization in the cytosol and at the plasma membrane is locally regulated by actin nucleators. Several microbial pathogens exploit cellular actin polymerization to spread through tissue. The movement of the enteric pathogen
Shigella flexneri
, both within the cell body and from cell to cell, depends on actin polymerization. During intercellular spread, actin polymerization at the bacterial surface generates protrusions of the plasma membrane, which are engulfed by adjacent cells. In the cell body, polymerization of actin by
Shigella
spp. is dependent on N-WASP activation of the Arp2/Arp3 complex. Here we demonstrate that, in contrast, efficient protrusion formation and intercellular spread depend on actin polymerization that involves activation of the Diaphanous formin Dia. While the
Shigella
virulence protein IpgB2 can bind and activate Dia1 (N. M. Alto et al., Cell
124:
133-145, 2006), its absence does not result in a detectable defect in Dia-dependent protrusion formation or spread. The dependence on the activation of Dia during
S. flexneri
infection contrasts with the inhibition of this pathway observed during vaccinia virus infection.
Mycobacterium lepraeActively Modulates the Cytokine Response in Naïve Human Monocytes
Authors: Sinsimer Daniel , Fallows Dorothy , Peixoto Blas , Krahenbuhl James , Kaplan Gilla , Manca Claudia
Published: October 2009

Leprosy is a chronic but treatable infectious disease caused by the intracellular pathogenMycobacterium leprae. Host immunity toM. lepraedetermines the diversity of clinical manifestations seen in patients, from tuberculoid leprosy with robust production of Th1-type cytokines to lepromatous disease, characterized by elevated levels of Th2-type cytokines and a suboptimal proinflammatory response. Previous reports have indicated thatM. lepraeis a poor activator of macrophages and dendritic cells in vitro. To understand whetherM. lepraefails to elicit an optimal Th1 immune response or actively interferes with its induction, we have examined the early interactions betweenM. lepraeand monocytes from healthy human donors. We found that, in naïve monocytes,M. lepraeinduced high levels of the negative regulatory molecules MCP-1 and interleukin-1 (IL-1) receptor antagonist (IL-1Ra), while suppressing IL-6 production through phosphoinositide-3 kinase (PI3K)-dependent mechanisms. In addition, low levels of proinflammatory cytokines were observed in association with reduced activation of nuclear factor-κB (NF-κB) and delayed activation of IL-1β-converting enzyme, ICE (caspase-1), in monocytes stimulated withM. lepraecompared withMycobacterium bovisBCG stimulation. Interestingly, although in itself a weak stimulator of cytokines,M. lepraeprimed the cells for increased production of tumor necrosis factor alpha and IL-10 in response to a strongly inducing secondary stimulus. Taken together, our results suggest thatM. lepraeplays an active role to control the release of cytokines from monocytes by providing both positive and negative regulatory signals via multiple signaling pathways involving PI3K, NF-κB, and caspase-1.
Gillnet Selectivity and a Model for Capture Probabilities for a Stunted Brown Trout (Salmo trutta) Population
Authors: Borgstrøm Reidar , Plahte Erik
Published: October 2009

The gillnet selectivities for a lacustrine population of allopatric brown trout (Salmo trutta) were estimated directly, using maximum girth as the parameter for fish size. A model for capture probabilities separating the processes of encountering the net and being retained in case of an encounter was developed. Swimming distances and retention probabilities were estimated from the model. Size selectivities decreased with increasing mesh size and fish size. This was explained by decreasing swimming distances with increasing fish size. The retention probabilities are consistent with a geometrical similarity hypothesis. Serious errors in the assessment of population size structure by gillnetting may arise when variations in swimming distances are not accounted for.
Changes in Maturity, Plasma Sex Steroid Levels, Hepatic Mixed-Function Oxygenase Activity, and the Presence of External Lesions in Lake Whitefish (Coregonus clupeaformis) Exposed to Bleached Kraft Mill Effluent
Authors: Munkittrick K. R. , McMaster M. E. , Portt C. B. , Kraak G. J. Van Der , Smith I. R. , Dixon D. G.
Published: October 2009

Lake whitefish (Coregonus clupeaformis) exposed to primary treated bleached kraft mill effluent (BKME) had reduced gonadal development and increased liver size relative to two reference populations. These results parallel our previous work on the white sucker (Catostomus commersoni) exposed to BKME at the same Lake Superior site. More detailed studies conducted in 1990, after the installation of an aeration stabilization basin at the pulp mill, found that lake whitefish exhibited reduced gonad sizes, delayed age to maturation, decreased levels of the plasma sex steroids testosterone and 17β-estradiol, and elevated hepatic mixed-function oxygenase (MFO) activity. Liver size was smaller following operation of the secondary treatment system. More than 20% of the lake whitefish collected at the BKME site in 1990 exhibited lateral, slash-like lesions which penetrated the body cavity. Histological examination revealed no evidence of an infectious etiology, and the wounds could not be accounted for by known causes. Similar lesions were found in 1991 near a second BKME discharge.
Dynamics of Energy Storage in a Freshwater Predator (Nephelopsis obscura) following Winter Stresses
Authors: Reddy D. C. , Dratnal Emil , Davies Ronald W.
Published: October 2009

Two groups of Nephelopsis obscura were maintained under identical conditions (20 °C, 100% dissolved oxygen, 12 h light: 12 h dark regime, ad libitum food) from post-hatchling size (10–11 mg) to sexual maturity (500–700 mg). One group (winter N. obscura) had overwintered in the field and degrown to 10–11 mg, while the other group (summer N. obscura) had hatched in the laboratory. The winter N. obscura at post-hatchling size had significantly lower accumulations of total lipid (3.9%), total protein (50.7%), free amino acids (1.6%), and glycogen (3.4%) than summer leeches, indicating that winter stresses (low water temperatures, low dissolved oxygen, restricted prey availability) had reduced energy stores and caused degrowth. The cryoprotective glycerol concentration, however, was significantly higher (1.9%) in winter leeches. At or just prior to sexual maturity, both winter and summer leeches showed decreases in total protein, glycogen, and total lipid which were attributed to the increased energetic demands of gametogenesis and maturation. The effects of, and compensation for, winter stresses were evident throughout the development of the winter leeches which exhibited enhanced energy allocation to storage compared with summer leeches.
Ruffe, Gymnocephalus cernuus: Newly Introduced in North America
Authors: Pratt Dennis M. , Blust William H. , Selgeby James H.
Published: October 2009

The Eurasian ruffe, Gymnocephalus cernuus, was collected from the lower St. Louis River, Lake Superior's westernmost tributary, in late summer 1987. This is the first known occurrence of the ruffe in North America. The likely vector for this species was ballast water of a transoceanic vessel dumped into the international port of Duluth-Superior located on the lower end of the St. Louis River. The ruffe is increasing in abundance and expanding its range into other tributaries and nearshore areas of Lake Superior.
Reliability of Selection Curves Obtained from Trouser Trawl or Alternate Haul Experiments
Authors: Cadigan N. G. , Millar R. B.
Published: October 2009

This study presents simulation results from a comparison of three methods for estimating selection curves from selectivity trials where the experimental codend of a trawl is fished in conjunction with a "control" (small mesh) codend. Methods 1 and 2 are based on the traditional approach of fitting selection curves to the so-called "proportion retained," the ratio of experimental codend to control codend catch, at each length class. Method 3 fits to the proportion of the total (control codend plus experimental codend) catch of each length class that is from the experimental codend. The traditional approaches exhibited considerable bias and consistently overestimated the 50% retention length and selection range. This partly explains why, in the published literature, trouser trawl experiments typically give higher estimates of the 50% retention length than covered codend experiments. Method 3 displayed little or no bias and always had lowest mean square error of the three methods. It is shown that the 50% retention length and selection range estimated by method 3 are approximately normally distributed for modest sample sizes.
Use of a Binomial–Normal Functional Model to Demonstrate that the Sex and Age Composition of Pacific Hake (Merluccius productus) Aggregations Affects Estimates of Mean Lengths-at-Age
Authors: Smith Barry D. , Saunders Mark W. , McFarlane Gordon A.
Published: October 2009

We present statistical evidence that estimates of mean length-at-age from a single aggregation of Pacific hake (Merluccius productus) are unlikely to represent those for the entire local population because fish length varies with age and sex, and fish aggregations are probably structured by fish size. We present series of simple linear relationships between estimates of mean length-at-age from hake sample sets and both the proportion of males and the proportions-at-age in those sample sets. To determine these relationships, we developed a likelihood-based model which incorporated model and sampling uncertainty in estimates of mean lengths-at-age, and sampling uncertainty in the estimated proportions of males or proportions-at-age. The results show that if fish length varies with sex or age, then the mean lengths-at-age estimated from a single sample set will be predictably, although perhaps modestly, influenced by the age and sex composition of the sample set. Thus, estimates of population mean lengths-at-age, and other sex–age–size statistics of fish that form aggregations, should be based on the premise that an aggregation of fish, not an individual fish, is the basic sampling unit.
Assessment of the Impact of Heavy Metals on Benthic Communities at the Clinch River (Virginia): Evaluation of an Index of Community Sensitivity
Authors: Clements William H. , Cherry Donald S. , Hassel John H. Van
Published: October 2009

Benthic communities (sampled once annually from 1986 to 1989) at stations impacted by copper and zinc were characterized by reduced species richness, reduced abundance, and a shift in community composition from sensitive to tolerant taxa. Benthic community structure varied annually due to fluctuations in stream discharge and improvements in water quality. Sensitivity of 13 dominant taxa to Cu was measured in outdoor experimental streams by exposing organisms to Cu (25 μg/L) for 10 d. Sensitivities (si), defined as proportioned reduction in abundance in treated streams relative to controls, ranged from 1.00 for several species of Ephemeroptera that were completely eliminated to −0.14 for taxa that increased in treated streams (Chironomidae: Orthocladiini). An index of community sensitivity (ICS) based on siand relative abundance of dominant taxa (pi) was developed for the Clinch River. The ICS was highly sensitive to heavy metals and useful for distinguishing reference and impacted stations. There was good agreement between the ICS and other community-level approaches in identifying impacted stations. We suggest that specific ICS values, based on siestimates of dominant taxa within a region, may be employed to predict the degree of metal impact in other streams within that region.
Factors Affecting Sampling Variability of Freshwater Periphyton and the Power of Periphyton Studies
Authors: Morin Antoine , Cattaneo Antonella
Published: October 2009

Estimates of periphyton abundance, biomass (as biovolume, chlorophyll, dry mass, or ash-free dry mass), and production were reanalyzed to examine the effect of the mean value, sampler size, type of substratum, and habitat on the variance of these estimates. There were strong relationships between the variance and the mean for all variables considered. Variability per sampling unit increased with sampler size for all variables except production and biovolume, which were both unaffected. Chlorophyll estimates were significantly less variable on artificial than on natural substrata, but this trend was not confirmed by other variables. For biovolume, the trend was reversed. Habitat affects periphyton variability only for some variables: production was more variable in streams than in lakes whereas chlorophyll was less variable in artificial streams than in any other habitat. Although periphyton tends to be less patchy than benthos, detection of small differences still requires a very intense sampling effort. Since the median replication is 3–10 in most published studies, only large differences can be detected with 95% probability, from twofold for the most precise variable (biovolume) to eightfold for the less precise variable (dry mass). Our ability to detect patterns in periphyton ecology is thus very limited.
Changes in the Olfactory Function of Atlantic Salmon, Salmo salar, in the Course of Smoltification
Authors: Morin Pierre-Philippe , Døving Kjell B.
Published: October 2009

Electrophysiological responses were recorded from the surface of the rostromedial and rostrolateral regions of the right olfactory bulb of Atlantic salmon, Salmo salar, during stimulation of the olfactory epithelium with different concentrations of L-alanine and taurocholate. Fish exposed to taurocholate prior to testing were compared with nonexposed fish. The results revealed significant week-to-week differences in olfactory activity in nonexposed fish, with two peaks in activity of similar magnitude. The first peak occurred at the beginning of smoltification, when olfactory sensitivity reached its maximum (low response threshold). The second peak occurred after smoltification, when sensitivity was roughly 10 times lower (higher response threshold) than during the first peak. Fish exposed to taurocholate prior to testing did not exhibit these peaks in olfactory activity. Marked changes in the spatial distribution of the electrophysiological response to L-alanine and taurocholate occurred throughout the smoltification process in nonexposed fish. The two peaks in olfactory activity that we identified coincide with two peaks in odor learning (Morin et al. 1989. Can. J. Fish. Aquat. Sci. 46: 122–130, 131–136); the first coincides with a unique capacity for odor memory and is apparently a neural manifestation of a sensitive period for olfactory imprinting in Atlantic salmon.
Historic Changes in Lake Michigan Zooplankton Community Structure: The 1960s Revisited with Implications for Top-Down Control
Authors: Evans Marlene S.
Published: October 2009

Recent changes in the Lake Michigan ecosystem provide a benchmark against which to reevaluate historic data. During the 1960s, the alewife (Alosa pseudoharengus) population exploded and then crashed. Offshore zoo-plankton data for the summers of 1954, 1966, and 1968 provided evidence that variations in alewife abundance had a major effect on zooplankton community structure. Based on these observations, other researchers have hypothesized that increased and decreased phytoplankton abundances during the 1960s as recorded at the Chicago water filtration plant were due to top-down effects rather than to phosphorus loading. This argument is reevaluated using two approaches. First, from the relationship between interannual variability in alewife and zooplankton species abundance during the summers of 1954, 1966, 1968, 1977, 1982, and 1984–87, I conclude that the effects of alewife predation on zooplankton community structure during the 1960s are less clear then originally proposed. Second, from estimates of Daphnia spp. grazing rates, considerations of the source of the long-term phytoplankton data used to support the top-down argument, regional differences in phytoplankton, zooplankton and alewife abundance trends, and historic water clarity observations, I conclude that existing data are insufficient to support the top-down argument that long-term trends in phytoplankton abundance were primarily affected by fluctuations in alewife abundance.
MECHANISM AND ENERGY RANDOM ANALYSIS OF TRAIN DERAILMENT ON RAILWAY BRIDGES
Authors: XIANG J. , ZENG Q. Y.
Published: October 2009

In this paper, the mechanism of train derailment on bridge is developed by applying the system dynamics stability concepts. The theory of energy random analysis for train derailment on bridge is put forward. The contents of the theory are as follows: (1) establishing vibration equation set for the train–bridge system; (2) determining exciting source of transverse vibration of the system; (3) method of energy random analysis of transverse vibration of the system; (4) geometric rules of derailment; (5) calculation of the whole process of train derailment on bridge; (6) criteria of energy increment for judging train derailment on bridge. Finally, three cases concerning train derailment on bridges are treated that coincide with actual conditions. Some main conclusions obtained are: (1) insufficient transversal rigidity of bridge is the reason causing train derailment on bridge and (2) enhancing transversal rigidity of bridge is the main preventive measure against train derailment on bridge.
PHYSICAL PARAMETER IDENTIFICATION OF AN RC FRAME STRUCTURE ON ELASTIC FOUNDATION
Authors: ZHOU YUN , YI WEI-JIAN
Published: October 2009

In this paper, the simple genetic algorithm (SGA) is improved by combining with the simulated annealing algorithm (SAA) for the parameter identification of a reinforced concrete (RC) frame on elastic foundation. SGA adopts parallel search strategy, which is based on the concept of "survival of the fittest" in optimization while SAA adopts a serial form and the process is endowed with time-variety probable jumping property so that local optimization could be prevented. The global searching ability is developed by combining the two methods and the new algorithm is named genetic annealing hybrid algorithm (GAHA). Modal experiments were carried out on a four-storey RC frame structural model with isolated embedded footings in laboratory. The measured natural frequencies and mode shapes have been utilized to identify the physical parameters of the frame by the proposed method. Four cases of concrete elastic modulus and foundation dynamic shear modulus are identified, and the results are compared with the usual sensitivity methods (SM). By model updating, the results show that the elastic modulus of concrete increases with respect to the storey. The identified elastic modulus of the concrete is generally larger than that found by compressive testing because the dynamic modulus of concrete is larger than the static modulus of concrete. The identified soil dynamic shear modulus also increases with the storey since the soil property depends on the pressure exerted on the soil. It is also shown that the identified results by GAHA are better than that of SM.
DAMAGE DETECTION OF RC SLABS USING NONLINEAR VIBRATION FEATURES
Authors: ZHU XINQUN , HAO HONG
Published: October 2009

Studied herein are the signatures of nonlinear vibration characteristics of damaged reinforced concrete structures using the wavelet transform (WT). A two-span RC slab built in 2003 was tested to failure in the laboratory. Vibration measurements were carried out at various stages of structural damage. The vibration frequencies, mode shapes, and damping ratios at each loading stage were extracted and analyzed. It is found that the vibration frequencies are not sensitive to small damages, but are good indicators when damage is severe. The dynamic responses are also analyzed in the time–frequency domain by WT and the skeleton curve is constructed to describe the nonlinear characteristics in the reinforced concrete structures. The results show that the skeleton curves are good indicators of damage in the reinforced concrete structures because they are more sensitive to small damages than vibration frequencies.
STATIC AND DYNAMIC PERFORMANCE EVALUATION OF A PRE-STRESSED CONCRETE BRIDGE THROUGH FIELD TESTING AND MONITORING
Authors: CAI C. S. , ARAUJO M. , NAIR A. , SHI X.
Published: October 2009

This paper presents field tests performed on a slab-on-girder pre-stressed concrete bridge. The bridge was tested under static loading, crawling loading, and dynamic loading. A full three-dimensional finite element prediction under both static and dynamic loadings was carried out and the results were compared with the field measurements. While acoustic emission (AE) monitoring of bridge structures is not a new vista, the method has not been fully exploited in bridge monitoring. Though numerous quantitative methods have been proposed, they have not yet developed to be useful for actual field tests of bridges. Therefore, in this study, an attempt was made to use the intensity analysis technique for damage quantification using the AE method.
STRUCTURAL DAMAGE IDENTIFICATION USING A GLOBAL OPTIMIZATION TECHNIQUE
Authors: BAYISSA W. L. , HARITOS N.
Published: October 2009

This paper presents a two-stage, vibration-based structural damage detection, localization, and severity estimation using an adaptive simulated annealing (ASA) global optimization technique. First, a "damage-sensitive" response parameter that has a strong physical relationship with structural physical properties is presented for detection and localization of structural damage using a nonmodel-based damage identification approach. Secondly, an ASA optimization algorithm is employed to estimate structural damage severity via minimization of a cost-function expressed in terms of the scalar distance between the "damage-sensitive" response parameter determined from a potentially damaged structure and that computed from a finite element model of the undamaged structure. The significance of this study is that the method can be used for damage detection, localization, and estimation of damage severity in two stages and can be applied to input-output as well as output-only damage identification problems. Finally, the proposed technique is demonstrated on simulated data obtained from a simply supported reinforced concrete beam and experimental modal data obtained from the I-40 Bridge.
APPLICATIONS OF THE ŁOJASIEWICZ–SIMON, GRADIENT INEQUALITY TO GRADIENT-LIKE EVOLUTION EQUATIONS
Authors: CHILL RALPH , HARAUX ALAIN , JENDOUBI MOHAMED ALI
Published: October 2009

We prove convergence to equilibrium of global and bounded solutions of gradient-like evolution equations. Our abstract results are illustrated by several examples in finite and infinite dimensions.
LARGE AND BOUNDED SOLUTIONS FOR A CLASS OF NONLINEAR SCHRÖDINGER STATIONARY SYSTEMS
Authors: GHANMI ABDEJABBAR , MÂAGLI HABIB , RĂDULESCU VICENŢIU , ZEDDINI NOUREDDINE
Published: October 2009

In the present paper, we are concerned with entire radially symmetric solutions of nonlinear Schrödinger elliptic systems in anisotropic media. In terms of the growth of the variable potential functions, we establish conditions such that the solutions are either bounded or blow up at infinity.
POSITIVITY OF GREEN'S FUNCTIONS TO VOLTERRA INTEGRAL AND HIGHER ORDER INTEGRO-DIFFERENTIAL EQUATIONS
Authors: GIL' M. I.
Published: October 2009

We consider Volterra integral equations and arbitrary order integro-differential equations. We establish positivity conditions and two-sided estimates for Green's functions. These results are then applied to obtain stability and positivity conditions for equations with nonlinear causal mappings (operators) and linear integro-differential parts. Such equations include differential, difference, differential-delay, integro-differential and other traditional equations.
Enabling Self‐Organization in Embedded Systems with Reconfigurable Hardware
Authors: Bobda Christophe , Cheng Kevin , Mühlbauer Felix , Drechsler Klaus , Schulte Jan , Murr Dominik , Tanougast Camel
Published: October 2009

We present a methodology based on self‐organization to manage resources in networked embedded systems based on reconfigurable hardware. Two points are detailed in this paper, the monitoring system used to analyse the system and the Local Marketplaces Global Symbiosis (LMGS) concept defined for self‐organization of dynamically reconfigurable nodes.
Effect of Physical Activity and Obesity on Type 2 Diabetes in a Middle-Aged Population
Authors: Ansari Rashid M.
Published: October 2009

Background. The physical activity has been associated with a reduced risk of type 2 diabetes. The aim of this study was to examine the effect of physical activities such as occupational, household and daily lifestyle activities and obesity on the prevalence of type 2 diabetes in middle-aged population.Methods. All people (n= 2053), aged 45–64 years were selected for this study from the large sample of population-based cross-sectional data collected in the 1990–1994 by National Health Survey of Pakistan. The participants completed in-person interviews at baseline; the overall response rate was 92.6%. The Cox proportional hazards model was used to estimate the risk of developing the type 2 diabetes.Results. Stair climbing was found to be inversely associated with the risk of diabetes and cycling was also associated with a reduced risk of type 2 diabetes (; 95% CI 0.68–1.00, ). The relationship between physical activity and reduced risk of diabetes adjusted for age and body mass index was statistically significant only in women ().Conclusions. This study provides an incentive that physical activity in leisure-time exercise or daily activity reduces the risk of type 2 diabetes in a high-risk population.
YSZ‐Based Oxygen Sensors and the Use of Nanomaterials: A Review from Classical Models to Current Trends
Authors: López-Gándara Carlos , Ramos Francisco M. , Cirera Albert
Published: October 2009

This work reviews physicochemical models on the operation and the response of potentiometric oxygen gas sensors based on ion‐conducting electrolytes. The aim for describing the electric response and some properties like response time, ionic conductivity, catalytic activity, or gas selectivity of these devices has led to the development of some models in the last decades. These models have provided information on relations between the response of the sensors, their design and fabrications process, and some morphological properties, like grain size of the electrolyte, diffusion on protective layers, or density of three‐phase boundary points in the measuring electrodes. Current trends on improving catalysis, gas selectivity, and activation energy for ion conducting by using nanomaterials are described as well.
Influence of Overt Diabetes Mellitus on Cyclosporine Pharmacokinetics in a Canine Model
Authors: Alkharfy Khalid M.
Published: October 2009

Background/Aims. Diabetic patients usually require more medications than their nondiabetic counterparts. This work examined the effect of hyperglycemia on the pharmacokinetic properties of cyclosporine in a diabetic dog model.Main Methods. Diabetes was induced using a streptozotocin/alloxan combination and verified by measuring the serum glucose level. Cyclosporine was administered as a bolus intravenous dose of 5 mg/kg, and blood samples were collected at different time points for determining drug concentrations and biochemical analyses.Results. Diabetic dogs showed a significant increase in total body clearance of cyclosporine compared to healthy controls (0.457 L versus 0.201 L , ) and a decrease in its biological half-life (9.32 hours versus 22.56 hours, ). In addition, diabetic animals exhibited a higher total cholesterol ( mmol/L and  mmol/L; ) as well as more serum low density lipoproteins ( mmol/L versus  mmol/L; ).Conclusion. Overt diabetes alters cyclosporine disposition by modulating its clearance. Abnormalities in the lipid profile, among other factors, may contribute to the accelerated metabolic degradation of cyclosporine under hyperglycemic conditions.
The Use of a Meckel's Diverticulum in the Creation of an Orthotopic Neobladder in Case of a Short MesoIleum: A Case Report
Authors: Van Haute Wim , Ghysel Christophe , Van Oyen Peter
Published: October 2009

A 72-year-old patient was treated in our department for an invasive bladder TCC by cystoprostatectomy with the intention to create an orthotopic neobladder. During surgery it appeared to be impossible to mobilize part of the preterminal ileum into the small pelvis to make an anastomosis with the urethral stump. However, incidentally, a Meckel's diverticulum of about 8 cm was found on the preterminal ileum which could easily be mobilized onto the urethral stump. The intestinal insertion of the diverticulum served as the lowest point of the pouch. Above the diverticulum, we created a modified Studer-pouch. No major postoperative complications occurred and during the follow-up period of more than 12 months micturition was good.
[Retracted] Multi‐Agent Systems in Control Engineering: A Survey
Authors: Daneshfar Fatemeh , Bevrani Hassan
Published: October 2009

This paper presents a survey on multi‐agent system (MAS) capabilities in control engineering applications. It describes essential concepts of multi‐agent systems that are related to the control systems and presents an overview on the most important control engineering issues which MAS can be explored. Most important technical aspects in MAS implementation and development in engineering environment are also explained. Design methodologies, standards, tools, and supporting technologies to provide an effective MAS‐based control design are addressed and a discussion on important related standards and protocols is given. Finally, some comments and new perspectives for design and implementation of agent‐based control systems are presented.
Hyers‐Ulam Stability of Nonhomogeneous Linear Differential Equations of Second Order
Authors: Li Yongjin , Shen Yan
Published: October 2009

The aim of this paper is to prove the stability in the sense of Hyers‐Ulam of differential equation of second order y′′ + p(x)y′ + q(x)y + r(x) = 0. That is, if f is an approximate solution of the equation y′′ + p(x)y′ + q(x)y + r(x) = 0, then there exists an exact solution of the equation near to f.
An Order on Subsets of Cone Metric Spaces and Fixed Points of Set-Valued Contractions
Authors: Asadi M. , Soleimani H. , Vaezpour S. M.
Published: October 2009

In this paper at first we introduce a new order on the subsets of cone metric spaces then, using this definition, we simplify the proof of fixed point theorems for contractive set-valued maps, omit the assumption of normality, and obtain some generalization of results.
Protective Effect of Melatonin Against Mitomycin C‐Induced Genotoxic Damage in Peripheral Blood of Rats
Authors: Ortega-Gutiérrez S. , López-Vicente M. , Lostalé F. , Fuentes-Broto L. , Martínez-Ballarín E. , García J. J.
Published: October 2009

Mitomycin C (MMC) generates free radicals when metabolized. We investigated the effect of melatonin against MMC‐induced genotoxicity in polychromatic erythrocytes and MMC‐induced lipid peroxidation in brain and liver homogenates. Rats (N= 36) were classified into 4 groups: control, melatonin, MMC, and MMC + melatonin. Melatonin and MMC doses of 10 mg/kg and 2 mg/kg, respectively, were injected intraperitoneally. Peripheral blood samples were collected at 0, 24, 48, 72, and 96 hours posttreatment and homogenates were obtained at 96 hours posttreatment. The number of micronucleated polychromatic erythrocytes (MN‐PCE) per 1000 PCE was used as a genotoxic marker. Malondialdehyde (MDA) plus 4‐hydroxyalkenal (4‐HDA) levels were used as an index of lipid peroxidation. The MMC group showed a significant increase in MN‐PCE at 24, 48, 72, and 96 hours that was significantly reduced with melatonin begin coadministrated. No significant differences were found in lipid peroxidation. Our results indicate that MMC‐induced genotoxicity can be reduced by melatonin.