bluuebunny/crossref_metadata_2025 huggingface dataset:
Seasonal Reproductive Patterns of Pumpkinseed (Lepomis gibbosus) Populations with Varying Body Size Characteristics
Authors: Danylchuk Andy J. , Fox Michael G.
Published: June 2008

To assess the implications of reproduction on body size and the potential physiological constraint imposed by small body size on reproductive patterns, we examined seasonal nesting patterns and gonad allocation in six pumpkinseed (Lepomis gibbosus) populations exhibiting a range of adult body size characteristics, We found that the two populations exhibiting stunted adult body size initiated nesting activity 1-wk later and had nesting periods 3–7 wk longer than the other four populations. Mean adult body size showed a significant negative correlation with both length of spawning season and gonadosomatic index in the six populations. Within populations, smaller females matured later in the season than larger females. Our results suggest that small adult body size is associated with high reproductive effort and that variation in the timing of reproduction is a consequence of differences in energy reserves between small and large individuals. The extended spawning season of some populations may result in a higher cost of reproduction than that which would be predicted from gonad size alone. Small individuals forced by energy limitations to spawn late in the season are likely to produce offspring with lower survival rates, and their reproductive fitness should be discounted accordingly.
Sources of Variation in Growth of the European Eel (Anguilla anguilla) Estimated from Otoliths
Authors: Panfili Jacques , Ximénès Marie-Claude , Crivelli Alain J.
Published: June 2008

Tetracycline labelling of otoliths was used for studying the growth of the European eel (Anguilla anguilla), which has strong individual variability. Two groups of eels were injected with tetracycline and released into a natural pond (Camargue, south of France) in spring 1989 and in autumn 1989. The marginal growth of otoliths between marking (tetracycline mark) and capture (otolith margin) was measured for all fish sampled until spring 1990. Comparisons of otolith growth rates were made according to fish size, age, sex, and growth period (ANCOVA). The results showed a great variability. After 15 mo of growth, the mean growth in length (back-calculated) was 6.6 cm. The three main factors tested, age, sex, and seasonal growth period, had a significant effect on otolith growth and therefore on somatic growth, since the relation between fish length and that of the otolith is highly significant (r2 = 0.802). There was also a very significant effect of size at marking on otolith growth. It is difficult to rank qualitative importance of these various factors, even though there are no interactions among them. The best absolute growth in Mediterranean lagoons could be attained by 2-yr-old female fish growing in the summer months.
Growth Rate of 0+ Fish in Relation to Temperature, Body Size, and Food in Shallow Eutrophic Lake Tjeukemeer
Authors: Mooij W. M. , Lammens E. H. R. R. , Densen W. L. T. Van
Published: June 2008

The growth rate of young-of-the-year of the six most abundant fish species (smelt (Osmerus eperlanus), pikeperch (Stizostedion lucioperca), perch (Perca fluviatilis), ruffe (Gymnocephalus cernua), bream (Abramis brama), and roach (Rutilus rutilus)) in Lake Tjeukemeer was predicted from water temperature using the model [Formula: see text]. For each species the model parameters were estimated using data from approximately 120 field observations of body size over a period of 13 yr; about 94% of the variance in body size could be explained by the model. The growth rate was correlated with temperature for all planktivorous species, except smelt. The relationship between growth rate and temperature was also significant for piscivorous pikeperch but not for benthivorous ruffe. These conclusions were corroborated by comparing the unexplained sum of squares of the temperature growth model with that of a temperature-neutral, logistic growth model. The abundance of food was not related to the temperature-corrected growth rate of planktivorous fishes, except in one year during which food conditions were extremely poor. We concluded that in most years the growth rate of 0+ planktivorous fish was not food limited. For piscivorous pikeperch, however, the variation in growth rate could be explained by the higher availability of smelt in warmer years.
Metabolic Costs and Physiological Consequences of Acclimation to Aluminum in Juvenile Rainbow Trout (Oncorhynchus mykiss). 1: Acclimation Specificity, Resting Physiology, Feeding, and Growth
Authors: Wilson Rod W. , Bergman Harold L. , Wood Chris M.
Published: June 2008

Juvenile rainbow trout (Oncorhynchus mykiss, 5–13 g) became acclimated (i.e., increased their resistance to lethal Al levels, 162 μg∙L−1, pH 5.2) after only 5 d when exposed to sublethal AS (38 μg∙L−1) in acidified soft water (Na+ = 85, Ca2+ = 28 μEq∙L−1, pH 5.2). Acclimation was associated with reduced ionoregulatory and respiratory disturbances during lethal Al challenge and was maintained for at least 34 d. Acclimation was relatively specific to Al because no consistently improved resistance to lethal Cu (32 μg∙L−1, pH 5.2) was observed. Exposure to sublethal acid alone (pH 5.2) did not result in acclimation to lethal [H+] (pH 4.0) and caused a pronounced reduction in whole-body Na+and Cl−. Sublethal acid + Al resulted in a more rapid loss of ions than sublethal acid alone over the first 10 d, but both groups subsequently recovered ionoregulatory status after 34 d. Exposure to sublethal acid alone had a negligible effect on feeding or growth. However, growth was impaired by 29% in Al-exposed trout, primarily the result of reduced appetite during the first 10 d. Decreased growth must be considered one of the costs of acclimation during chronic sublethal exposure to Al.
A Likelihood Method for Estimating Pacific Salmon Escapement based on Fence Counts and Mark–Recapture Data
Authors: Labelle M.
Published: June 2008

Pacific salmon escapements in natural streams are often determined by conducting fence counts in conjunction with mark–recapture operations. Typical field conditions are characterized by protracted floods, undetected immigration, variation in sampling rates, mortality during the census periods, small sample sizes, and few successive recaptures. Closed population models tend to overestimate escapement under such conditions, and traditional open population models cannot always be relied on due to the lack of sufficient data. A likelihood-based estimation method was specifically designed for such conditions. A distinguishing feature of this model is that individual recapture histories are not required for parameter estimation. The model is also structured to incorporate ancillary data in the estimation process to improve the precision and accuracy of the estimates. The model is described in detail, and suggestions are made to facilitate its application. Constructed data sets resembling those obtained under field conditions were used to evaluate the performance of the model. The estimates generated with simulated data and actual field data were compared with those based on visual foot surveys and other mark–recapture models.
Identifying Habitat Associations of Marine Fishes Using Survey Data: An Application to the Northwest Atlantic
Authors: Perry R. Ian , Smith Stephen J.
Published: June 2008

We present an objective method for identifying associations between environmental (habitat) conditions and the distributions of marine fishes using survey data. The method tests the null hypothesis of a random association between fish distribution and habitat conditions. We apply this method to bottom depth, temperature, and salinity data and to the distributions of four groundfish species (yellowtail flounder (Pleuronectes ferruginens, previously Limanda ferruginea), haddock (Melanogrammus aeglefinus), silver hake (Merluccius bilinearis), and Atlantic cod (Gadus morhua)) from trawl surveys of the eastern Scotian Shelf (northwest Atlantic) conducted in winter/spring (March) and summer (July) 1979–84. Haddock and silver hake maintained similar temperatures in winter and summer by changing their depth distributions (temperature-keepers), with haddock generally at cooler temperatures than silver hake. Yellowtail flounder (a depth-keeper) maintained similar depths between seasons while tolerating a wide range of temperatures and salinities. Atlantic cod were not consistently associated with particular depths in either sprang or summer, and we were unable to distinguish between temperature or salinity as a single factor modifying their distributions, perhaps because of age-related effects. Identification of persistent habitat associations of marine fishes provides an opportunity to improve fisheries management procedures.
Zooplankton Biomass in the Southern Gulf of St. Lawrence: Spatial Patterns and the Influence of Freshwater Runoff
Authors: Lafontaine Yves De
Published: June 2008

The role of advection of freshwater input in Zooplankton distribution was evaluated from 16 surveys carried out in the southern Gulf of St. Lawrence during 1967–71. Biomass was structured according to two main patterns: large-scale gradients (> 150 km) over the entire area and mesoscafe (≈25 km) patches. Patterns exhibited seasonal and interannual variability without any sign of recurrence through time, unlike the spatial structure of surface water temperature and salinity which was typical of large-scale dispersion gradients resulting from the seasonal input of freshwater into the area. In most cases, overall distribution patterns of biomass and hydrographic variables were not significantly correlated, indicating that biomass patterns in the southern Gulf were not related to water mass characteristics and advection of freshwater runoff over the entire area. Although mesoscale patchiness was unrelated to hydrographic processes, patch size (≈25 km) was similar to estimates obtained for the northern Gulf and for other coastal shelf areas. Large-scale gradients in biomass may correspond to species changes in relation to the salinity gradient and/or topography and bathymetric features. I conclude that biomass alone is not an adequate predictor for monitoring changes and variability of Zooplankton in response to runoff variability.
Age- and Sex-Specific Survival of Northern Grand Bank Capelin (Mallotus villosus)
Authors: Shackell Nancy L. , Shelton Peter A. , Hoenig John M. , Carscadden James E.
Published: June 2008

Age-specific, sex-specific survival rates for immature and mature capelin (Mallotus villosus) were estimated by linear least-squares models, using abundance data derived from annual acoustic/trawl research surveys conducted from 1982 to 1990 on the northern Grand Bank. Survival estimates for age 2 immature fish were comparable between sexes (annual survival equals approximately 40%). Survival estimates for age 4 mature fish differed between sexes, with females having a higher (25–51%) average survival estimate than males (6%). Survival estimates for immature and mature age 3 fish were equivocal; immature males and females had comparable rates (30.3–32.3 and 15.2–26.6%, respectively) whereas a greater proportion of mature females (25–50%) survived than of mature males (2.5–13%). The stated ranges denote survival estimates including and excluding an influential data point, respectively. Higher average survival of mature females than of mature males may be a result of sex-specific behavior during beach spawning. The average annual contribution of surviving mature females to the total number of female spawners was estimated as 24–47%.
Impacts of Flounder Trawls on the Intertidal Habitat and Community of the Minas Basin, Bay of Fundy
Authors: Brylinsky Michael , Gibson Jamie , Gordon Jr. Donald C.
Published: June 2008

Four experimental trawls were made at highwater over the intertidal zone of the Minas Basin and the effects assessed when the tide was out to determine the physical and biological impacts of groundfish trawling on the benthos. The trawl doors made furrows 30–85 cm wide and up to 5 cm deep. The rollers compressed surficial sediments but did not scour a depression. The bridle caused no obvious disturbance. Door furrows and roller marks remained visible for 2–7 mo. No significant impacts were observed on either benthic diatoms or macrobenthos. The macrobenthos was dominated by polychaetes, some of which may have the ability to take evasive action as a trawl approaches. There were few molluscs, crustaceans, or echinoderms present; these taxa have been shown to be more susceptible to trawling damage in studies done elsewhere. Nematode numbers were initially depressed in the door furrows but did recover with time. It is not known whether nematodes were killed or displaced but the latter is thought more likely. Overall, the impacts in this particular environment are judged to be minor, especially since the intertidal sediments of the Minas Basin are already exposed to similar natural stresses imposed by storms and winter ice.
Relative Importance of Algae and Emergent Plant Litter to Freshwater Marsh Invertebrates
Authors: Campeau Suzanne , Murkin Henry R. , Titman Rodger D.
Published: June 2008

We test the hypotheses that (1) algae are a major food source for marsh invertebrates and (2) plant litter serves mainly as cover for invertebrates and a substrate for algal growth rather than as a direct source of nutrition. Twelve enclosures (5-m diameter) were deployed in May in a nutrient-poor marsh of the Interlake region of Manitoba, six of which were fertilized to increase algal levels. The hardstem bulrush (Scirpus lacustris glaucus) litter present was replaced with a nonnutritive artificial substrate in half of the fertilized and unfertilized enclosures. Dominant taxa of nektonic herbivores–detritivores increased in abundance and biomass following algae manipulations but were not affected by the replacement of plant litter with a nonnutritive substrate. Epiphytic herbivores–detritivores responded to changes in both detritus and algal food sources, the importance of each factor varying among taxa. Fertilization resulted in early peaks of emergence for chironomids. In the first weeks of the study, chironomid emergence was not affected by the replacement of plant litter with a non-nutritive substrate. In August, however, more chironomids emerged in the treatments where plant litter was provided when compared with the artificial litter treatments.
Spatial Autocorrelation and Assessment of Habitat–Abundance Relationships in Littoral Zone Fish
Authors: Hinch Scott G. , Somers Keith M. , Coliins Nicholas C.
Published: June 2008

Spatial autocorrelation, wherein intersite similarity is correlated with distance between sites, is a characteristic of most ecological studies spanning a large environmental range. If data are spatially autocorrelated, classical statistical techniques provide biased estimates of relationships between species attributes and environmental variables. We examined abundances of seven littoral fishes in 25 lakes that varied substantially in morphometry, chemistry, and elevation across central Ontario. Weak correlations were observed between abundances of particular species and environmental variables before correcting for spatial autocorrelation, and we hypothesized that correlations reflected species' habitat preferences. However, spatial autocorrelation existed in the abiotic and fish abundance datasets. Once large-scale geographic patterns (spatial autocorrelation) were removed using partial Mantel tests, correlations changed within and between datasets. A strong relationship emerged between abundances and lake elevation. By comparing patterns within geographically corrected data with those without correction, we identified particular species that exhibited spatially autocorrelated abundances. The geographic direction of spatial autocorrelation provided additional insights into environmental factors also correlating with species abundance. We recommend that ecologists examine both geographically corrected and noncorrected data when developing hypotheses to explain regional variation in species abundance.
Une méthode simple d'ajustement des clés taille/âge : application aux captures d'albacores (Thunnus albacares) de l'Atlantique Est
Authors: Gascuel Didier
Published: June 2008

An adjustment method for age–length keys is presented that incorporates yearly variability in cohort abundances. The method is based on two models (one for growth and the other for standard deviations of length versus age) and involves an iterative algorithm. The algorithm rapidly converges to stable results that yield, under some conditions, maximum likelihood estimates. It is also used to estimate parameters of the length standard deviation model. The method is applied to yellowfin tuna (Thunnus albacares) catches in the eastern Atlantic from 1975 to 1989. Monthly keys, adjusted to catches from the entire fishery, show a high annual variability. These keys are used for length–age conversion by gear type and 5 geographic squares. Compared with previous estimates based on the "slicing" method, catches by age are noticeably corrected; they show a greater temporal variability. The results show a low sensitivity to parameter estimates of the length standard deviation model. The adjustment method for age–length keys is compared with classical likelihood-based methods for the separation of mixtures of normal distributions; it fits particularly well under conditions of known growth, it offers the advantages of simplicity and adaptability, and importantly, it allows the use of particular growth models.
Estimation of Size Selectivity and Movement Rates from Mark–Recovery Data
Authors: Anganuzzi Alejandro , Hilborn Ray , Skalski John R.
Published: June 2008

Size selectivity, movement rates among spatial strata, and size-dependent mortality rates were estimated from mark–recovery data of Pacific halibut (Hippoglossus stenolepis). Growth rates, area- and time-specific fishing mortality on fully vulnerable individuals, and tag return rates were assumed known from other data. We obtained similar estimates from a model that considered movement to take place immediately after tagging and a model that assumed that movement takes place once each year. The inability to distinguish between one-time and annual movement is most likely due to the fact that tagged juveniles were not recovered until 3–5 yr later when they became vulnerable to the adult fishery.
Electromagnetic wave-guide experiments for detecting light-speed anisotropy
Authors: Sfarti A
Published: June 2008

The Mansouri–Sexl theory is a well known test of the theory of relativity. The main test theories of special relativity (SR) are named after their authors, Robertson (Rev. Mod. Phys. 21, 378 (1949)) and Mansouri and Sexl (Gen. Rel. Grav. 8, 497 (1977); 8, 515 (1977); and 8, 809 (1977)). These test theories can also be used to examine potential alternate theories to SR — such alternate theories predict particular values of the parameters of the test theory, which can easily be compared to values determined by experiments analyzed with the test theory. The existing experiments put rather strong experimental constraints on any alternative theory. Mansouri and Sexl promised an electromagnetic version of their theory, but for some reason that part was never delivered. In the following paper, we will construct the electromagnetic version and will demonstrate its application to constraining light-speed anisotropy. PACS No.: 03.30.+p
Theoretical calculations of energy spectra and g factors of Cr3+ doped KAl(MoO4)2 crystal
Authors: Zhou H -B , Zhang J -P , Wu F
Published: June 2008

With the strong-field scheme and trigonal bases, by diagonalizing the complete d3 energy matrix in a trigonally distorted cubic field, the energy spectra and wave functions of KAl(MoO4)2:Cr3+ are calculated. By using the wave functions obtained from the diagonalization of the complete energy matrix, the g factors of the ground state of KAl(MoO4)2:Cr3+ are evaluated. The calculated results are in good agreement with the optical-spectral and electron paramagnetic resonance experimental data.PACS Nos.: 71.70.Ch, 71.70.Ej, 75.10.Dg, 76.30Fc
On the effect of gravitational and hydrodynamic forces on particle motion in a quiescent fluid at high particle Reynolds numbers
Authors: Rostami M , Ardeshir A , Ahmadi G , Thomas P J
Published: June 2008

Trajectories of 5 and 10 mm metallic and plastic particles in a quiescent liquid during their sedimentation toward a plate were studied using experimental and numerical means, and the influence of gravity, drag, added mass, and history forces were evaluated. Variations of particle diameter and density allowed measurements at Reynolds numbers, based on the impact velocity, in the range of 1 000 to 13 000. A computer model was developed and the Lagrangian equation of particle motion was solved. The results showed that the combination of gravity, drag, and added mass forces are important for the simulation of the motion of small particles for the duration of their flight from the starting point to the wall impact, in the range of particle Reynolds numbers between 1000 and 5000. Comparison of the simulation results with the data showed that the predicted trajectories underestimated the experimental observations by about 1% to 4.3%. When the history force was included in the governing equation, however, excellent agreement between the measured and predicted particle trajectory was obtained. Experimental results for the motion of large particles showed oscillations in the time history of particle velocity when the particle Reynolds number was in the range of 3 000 to 13 000. Repeating the experiment, and averaging the data of a large number of experiments, yielded averaged curves for the particle velocity that did not show oscillatory values. In this case, good agreement between numerical and experimental data was observed. The study also shows that at high particle Reynolds numbers, the effect of the history force becomes negligibly small.PACS No.: 47.55kf
Atomistic simulation of phonon dispersion for body-centred cubic alkali metals
Authors: Xie Y , Zhang J -M
Published: June 2008

Atomistic simulations of phonon dispersion for body-centred cubic alkali metals were carried out using the modified analytic embedded atom potentials. The expressions for atomic force constants are derived, the cohesive energy and elastic constants are calculated, and the phonon dispersion curves of Li, Na, K, Rb, and Cs are calculated along five principal symmetry directions. The calculated results are in good agreement with the available experiments. For all of the five alkali metals, in the same direction, a similar phonon dispersion curve is obtained in spite of the successive phonon frequency decreases for Li, Na, K, Rb, and Cs, which may be related to the atom mass increases or the cohesive energy decreases. PACS Nos.: 63.20.Dj, 71.20.Dg, 31.15.Ct
Teleportation of unknown atomic entangled states via Greenberger–Horne–Zeilinger class states
Authors: Xiong K -W
Published: June 2008

A physical scheme for teleporting unknown atomic entangled states via three-atom non-maximally entangled states is proposed in cavity quantum electrodynamics. In this scheme, the Greenberger–Horne–Zeilinger class states are used as quantum channels. The most distinct feature of our scheme is that, not only the effects of the cavity decay and thermal field are eliminated, but also the teleportation and distillation procedure can be realized simultaneously.PACS Nos.: 03.67.Hk, 03.67.Pp
Hyperfine interactions in H2N
Authors: Brill A S
Published: June 2008

All of the hyperfine interactions associated with localized and delocalized electron spin in the four isotopes of the triatomic radical H2N are treated. With nuclear Zeeman energy included, the resulting magnetic-field-dependent nuclear spin states are used to calculate the energies and nuclear spin-state mixing of the nuclear levels and the corresponding hyperfine effects upon electron paramagnetic resonance (EPR) transition energies and nuclear state transition probabilities. In the absence of nuclear spin-state mixing there would be, for example, 10 EPR transitions in D2 15N and 15 in D2 14N, all ΔmI = 0 fully allowed. In the presence of mixing, there are 243 in D2 15N and 729 in D2 14N, with large differences in probability among transitions, many 0 or small. Because of numerous (at least partially allowed) transitions, spectra from isotopes of H2 N radicals are the superposition of signals at greatly different levels of saturation. In this report, EPR spectra from D2 15N models, with either N or 2D hyperfine interaction suppressed, are simulated as a function of microwave frequency and power × spin-lattice relaxation time product. A large range of microwave frequency (and, concomitantly, magnetic field strength) will be needed to evaluate the effect of the nuclear Zeeman energy. The experimental requirements for microwave power and low temperature (long spin-lattice relaxation rate) are quantified.PACS Nos.: 33.15.Pw, 33.35.+r, 33.25.+k
Heat transfer over an unsteady stretching surface with prescribed heat flux
Authors: Ishak A , Nazar R , Pop I
Published: June 2008

The unsteady laminar boundary-layer flow over a continuously stretching surface in a viscous and incompressible quiescent fluid is studied. The unsteadiness in the flow and temperature fields is caused by the time dependence of the stretching velocity and the surface heat flux. The nonlinear partial differential equations of continuity, momentum, and energy, with three independent variables, are reduced to nonlinear ordinary differential equations, before they are solved numerically by the Keller-box method. Comparison with available data from the open literature as well as the exact solution for the steady-state case of the present problem is made, and found to be in good agreement. Effects of the unsteadiness parameter and Prandtl number on the flow and heat transfer characteristics are thoroughly examined.PACS No.: 47.15.Cb
Factors affecting student drop out from the university introductory physics course, including the anomaly of the Ontario double cohort
Authors: Slavin A
Published: June 2008

The course drop-out rate is the fraction of students per year who drop a course after starting it. This statistic is important both as a measure of the difficulty or relevance of the course compared to others at a university, and as one indication of the success of measures taken to improve teaching. The drop-out rate of students from the first-year university physics course at Trent University increased from about 8% in the 1980s to over 20% in 1999, primarily under the same instructor, with the exception of the Ontario “double-cohort” years 2003–2004 and 2004–2005 when it plummeted to about 9% before rebounding in 2005–2006. A similar decrease in this rate for the double-cohort years has been observed at Brock University and the University of Guelph, and so was probably widespread. It is speculated that the main cause of the decrease for these two years was an improved work ethic of the double-cohort students. Possible causes of the steady increase in the drop-out rate from the 1980s to the present are discussed including high-school courses taken; gender balance; and grade inflation. The last of these combined with a dramatic increase in the percentage of high-school students continuing their education, appears to have resulted in weaker and less motivated students being admitted to university. Results are also given of a survey of recent first-year Trent University physics students for possible reasons for dropping out of the course: students who have not taken the final-year high-school physics course, do not live in residence, or do not work together on their assignments are much more likely to drop the course.

PACS No.: 01.40.gb
Structure, magnetic and electrical properties of Ln2/3Pb1/3MnO3 (Ln = La, Pr, Nd) films
Authors: Han L A , Chen C L
Published: June 2008

Ln2/3Pb1/3MnO3 (Ln = La, Pr, Nd) films deposited on single crystal LaAlO3 substrate were fabricated using the RF magnetron sputtering method. The X-ray diffraction results of bulk targets indicate that with the decrease of the average ion radius < rA >, the structure transits from the rhombohedral to the orthorhombic phase. The magnetic properties show that there is a transition from the ferromagnetic to the paramagnetic state with the increase in temperature, the Curie temperature reduces abruptly with the decrease of < rA >. The electrical properties show that films are in the metallic state, which can be fitted to the formula: ρ(T) = ρ0 + ρ1T2 + ρ2T4.5 at low temperatures and the insulator state, which can be fitted to the formula: ρ(T) = ρ0T exp(Ea/KBT) at higher temperature(T > TMI). The temperature range of the ferromagnetic metallic state becomes narrow with the decrease of < rA >. The phenomenon can be qualitatively and reasonably explained by the double-exchange model and Jahn–Teller effects. PACS Nos.: 75.47.Lx, 74.25.Ha, 75.47.–m, 75.30.Et
Singular point analysis of the Gaudin equations
Authors: Schmidt J R
Published: June 2008

The Gaudin equations, a set of conditions of integrability imposed on the coupling constants of a lattice spin model, are solved by singular point analysis and the Painleve’ test. The Gaudin equations are transformed into systems of differential equations. The subset that are similarity-invariant have two, one, or zero constants of the motion corresponding to elliptic, trigonometric and (or) hyperbolic, and rational solutions, respectively. All solutions can be found at least formally by this technique. All similarity-invariant solutions are odd functions. There exist solutions with regular, even parts whose squares sum to a constant.PACS Nos.: 02.30.Ik, 02.40.Xx, 03.65.Fd
Generation of a superposition of coherent states in a resonant cavity and its nonclassicality and decoherence
Authors: Ghosh A , Das P K
Published: June 2008

We discuss nonclassicality of a superposition of coherent states in terms of sub-Poissonian photon statistics as well as the negativity of the Wigner function. We derive an analytic expression for the Wigner function from which we find that the function has some negative region in phase space. We obtain a compact form of the Wigner function when decoherence occurs and study the effect of decoherence on the state. We demonstrate the behavior of the nonclassicality indicator.PACS Nos.: 42.50.Dv, 03.65.Yz
Expanded calculations of proton–neutron quasi-particle random phase approximation (pn-QRPA) electron capture rates on 55Co for presupernova and supernova physics
Authors: Nabi J -U , Sajjad M
Published: June 2008

Because of its abundance and its relatively high capture rates, 55Co is one of the key nuclide that can control the dynamics of core collapse of a massive star. Previously we introduced our microscopic calculations of capture rates on 55Co using the proton–neutron quasi-particle random phase approximation (pn-QRPA) theory. Here, we present for the first time an expanded calculation of the electron capture rates on 55Co on an extensive temperature-density scale. This type of scale is appropriate for interpolation purposes and of greater utility for simulation codes.PACS Nos.: 26.50.+x, 21.60.Jz, 23.40.–s, 27.40.+z
Probabilistic seismic stability analysis — a case study
Authors: Athanasiou-Grivas D.
Published: June 2008

A previously developed model is used to provide a probabilistic seismic stability analysis for a natural slope located near Slingerlands, New York. The safety of the slope is measured in terms of its probability of failure rather than the customary factor of safety.Three types of possible earthquake sources are investigated, namely, a point, a line, and an area source. The dependence on significant seismic parameters of the probability of failure of the slope is examined and the results are presented in a number of graphs and tables.On the basis of the results obtained in this study, it is concluded that (a) the present model is useful in assessing the reliability of soil slopes under both static and seismic conditions; and (b) the probability of failure of a soil slope is greatly affected by the type of earthquake source involved and the values of the seismic parameters that are associated with it.
Reinforced earth retaining walls under strip load
Authors: Kennedy John B. , Laba Jan T. , Mossaad Mostafa A.
Published: June 2008

An analysis is presented to estimate the forces mobilized in reinforced earth retaining walls when subjected to a surcharge strip load. An estimate of the maximum traction force in a rein forcing element is deduced by a modification of Terzaghi’s formula for the computation of the lateral pressure against a conventional rigid retaining wall. Furthermore, a simple distribution is proposed for the traction force in a reinforcing element, and in consequence, the force transmitted to the facing of the wall. Tests on a wall model substantiate and verify the theoretical results. A worked example on the analysis of a reinforced earth retaining wall subjected to a surcharge strip load is given.
Peat fabric and structure
Authors: Landva A. O. , Pheeney P. E.
Published: June 2008

The results of various index tests and standard and scanning electron microscope examinations of Sphagnum and sedge peats form the basis for an investigation of peat fabric and structure.The volumetric and gravimetric relationships of a moderately humified Sphagnum peat are examined in detail, and phase diagrams are constructed for two Sphagnum peats with different degrees of humification. Tentative phase diagrams for a sedge peat are also presented.A brief examination is made of existing classification systems and of some aspects of the formation of peats.
Contribution of amorphous material to properties of a laboratory-prepared soil
Authors: Yong R. N. , Sethi A. J. , Suzuki A.
Published: June 2008

The presence and the importance of amorphous material are becoming recognized in sensitive soils and have been documented in previous studies. In order to further appreciate the specific contributions and influences of the varying composition of amorphous material to a sensitive soil, it is necessary to obtain a soil system where the individual components can be rigorously controlled and subjected to proper scrutiny. To achieve this, the laboratory-prepared soils were obtained by mixing synthesized amorphous iron–silica mixed hydroxides of varying composition with silt-sized particles of primary materials such as quartz, feldspar, or hornblende.In this study the influence of water content and the amount and composition of amorphous material mixed with nonclay minerals on the resultant sensitivity and basic engineering parameters is investigated.The results indicate that Atterberg limits of the laboratory-prepared sensitive soils are dependent upon the composition of amorphous material and that the trends established are similar to those obtained in similar tests on natural sensitive clays obtained from St. Alban, Outardes, and Gatineau. Similarly, the increase in shear strength and soil suction upon aging of the prepared sensitive soil is dependent upon the composition or molar ratio Fe2O3/(Fe2O3 + SiO2) of amorphous material.
An approach for the determination of the preconsolidation pressure in sensitive clays
Authors: Leroueil S. , LeBihan J. P. , Tavenas F.
Published: June 2008

The present methods for the determination of the preconsolidation pressure of clays are time consuming and expensive. A new method is proposed in which the clay is loaded in a "one-stage loading" to an axial stress in excess of the estimated preconsolidation pressure. The preconsolidation pressure is determined from the observation of the pore pressure dissipation within a few hours. The theoretical basis of this method is also used to discuss the method of interpreting constant rate of strain and constant gradient oedometer tests.
ANALYSIS OF GENERALIZED OPTIMAL CURRENT LATTICE MODEL FOR TRAFFIC FLOW
Authors: ZHU WEN-XING , CHI EN-XIAN
Published: July 2008

A generalized optimal current lattice model (GOCLM) for traffic flow is proposed to describe the motion of the dynamical traffic flow with a consideration of multi-interaction of the front lattice sites. In order to verify the reasonability of the new model, the stability condition is obtained by the use of linear stability theory. The modified KdV (Korteweg–de Vries) equation is derived by the use of the nonlinear analysis method and the kink-antikink soliton solution is obtained near the critical point. The propagation velocities of density waves are calculated for different numbers of the front interactions. A numerical simulation is carried out to check out the performance of GOCLM for traffic flow. The simulation results show that GOCLM is better than the previous models in suppressing the traffic jams.
OPTICAL COHERENCE OF A SCALAR WAVE INFLUENCED BY FIRST-ORDER AND SECOND-ORDER STATISTICS OF ITS RANDOM PHASE
Authors: CHAPEAU-BLONDEAU FRANÇOIS , GINDRE DENIS , BARILLÉ RÉGIS , ROUSSEAU DAVID
Published: June 2008

We analyze a simple model of a scalar optical wave with partial coherence. The model is devised to describe the influence on the coherence of the wave, of the statistical properties of its random phase, including both the second-order statistics (phase correlation) — which is classic, but also the first-order statistics (phase distribution) — which is nonclassic. Expectedly, upon increasing the disorder of the fluctuating phase through a reduction of its correlation duration, the model shows that the coherence of the wave is always reduced. By contrast, upon increasing the disorder of the fluctuating phase through an increase of its dispersion, the model reveals that the coherence of the wave can sometimes be enhanced. This beneficial consequence of an increase in disorder is related to the phenomenon of stochastic resonance or improvement by noise in signal processing.
PULSE CLUSTERING UNDER AVALANCHE BREAKDOWN OF INTENTIONALLY DESIGNED SILICON MICROPLASMA
Authors: BARANOUSKI ALEH K.
Published: June 2008

Intentionally designed silicon microplasmas with breakdown voltage 10.4–10.8 V have been investigated. Avalanche pulse rate time dependence and Fano factor were measured to evidence the presence of time-clustering in the series of pulses. The two-level fluctuations of avalanche pulse rate were observed for diodes containing two charge multiplication regions. Probabilistic model for pulse rate fluctuations was introduced.
THE RELAXATION TIME AND THE CORRELATION FUNCTION FOR A LOGISTIC GROWTH SYSTEM DRIVEN BY COLORED CROSS-CORRELATION NOISES
Authors: WANG CAN-JUN , MEI DONG-CHENG
Published: June 2008

The associated relaxation time Tc and the normalized correlation function C(s) are investigated in the logistic growth system, which is used to describe a tumor cell growth process, driven by two Gaussian white noise sources and the correlation between the additive and multiplicative noise. The expression of Tc and C(s), which is the function of noise parameters (additive noise intensity α, multiplicative noise intensity D, correlation intensity λ and correlation time τ), is obtained by using the projection operator method. After introducing noise intensity ratio, a dimensionless parameter R = α/D, and performing the numerical computations, the two case are analyzed: (1) In the growth case, λ and τ play opposite roles on the Tc and the C(s). It must emphasize that there is a minimal evolution velocity to appear and the tumor cell numbers is hard to evolve from an arbitrary initial condition to the maximum. (2) In the decay case, λ and τ play same roles on the Tc and the C(s). There is a maximal evolution velocity to appear. The noises induce different responses of tumor cells between the growth and decay case.
ANALYSIS OF TIME REGIMES IN FIRE SEQUENCES OCCURRED IN PATAGONIA, ARGENTINA
Authors: GHERMANDI LUCIANA , DE TORRES CURTH MONICA , FRANZESE JORGELINA , TELESCA LUCIANO
Published: June 2008

Time regimes in fire data recorded from 1992 to 2007 in a fire vulnerable area of Patagonia (Argentina) were revealed by using the Allan Factor statistics. The obtained results show the presence of seasonal periodicities, superimposed to three time-scaling regimes, which characterize the point process of the fire sequence as a fractal time process with a rather high degree of time-clusterization of the events.
PECULIARITIES OF SCALING IN MODELS OF DUFFING OSCILLATOR UNDER ACTION OF KICKS WITH RANDOM MODULATION OF PARAMETERS
Authors: KUZNETSOV ALEXANDER P. , SEDOVA JULIA V.
Published: June 2008

We study noise influence on universal properties of period-doubling cascade in a well-defined model of periodically kicked nonlinear dissipative oscillator. Two approaches of noise adding are considered: (i) modulation of kick's amplitude and (ii) modulation of the interval between kicks. We then derive corresponding stochastic discrete one- and two-dimensional maps and provide a detailed study of the noise scaling properties of the Feigenbaum scenario and of the non-Feigenbaum tricritical case. Illustrations of bifurcations trees and Lyapunov exponent charts are given.
DIFFUSIVE TRANSPORT IN PERIODIC POTENTIALS: UNDERDAMPED DYNAMICS
Authors: Pavliotis G. A. , Vogiannou A.
Published: June 2008

In this paper we present a systematic and rigorous method for calculating the diffusion tensor for a Brownian particle moving in a periodic potential which is valid in arbitrary dimensions and for all values of the dissipation. We use this method to obtain an explicit formula for the diffusion coefficient in one dimension which is valid in the underdamped limit, and we also obtain higher order corrections to the Lifson-Jackson formula for the diffusion coefficient in the overdamped limit. A numerical method for calculating the diffusion coefficient is also developed and is shown to perform extremely well for all values of the dissipation.
Assessment of string tests strategy for an en route air traffic control system
Authors: O'Leary Jeff , Woodard Frederick , Srivastava Alok , Beidleman Denise S.
Published: July 2008

The Federal Aviation Administration (FAA) depends upon several highly available large and complex computer systems to support air traffic control operations. One of the FAA's major initiatives, the Ada based En-Route Automation Modernization (ERAM) program leverages and significantly expands upon previous developed systems. To determine the effectiveness of the string test implementation before full system level testing, the FAA performed an audit of the software requirements that were verified by string tests.

An industry standard approach was used to determine the number of Shalls to be inspected. Detailed evaluation using multiple software documents and test plans were compared to the string test results provided by the development contractor.

This paper presents details of the audit, its results and reconciliation of the data with the development contractor.

The approach to have selected software Shalls verified through the string test method versus full system test resulted in a cost savings of 50% of the cost of the selected software Shalls' full system test, by avoiding duplication of testing efforts.

The resulting high pass rate of the audit gave confidence in the development contractor's string test results and also demonstrated a high confidence level in the code, thus confirming the high quality of the Ada code effort.
Evaluation of static source code analyzers for avionics software development
Authors: Bartholomew Redge
Published: July 2008

This paper describes an evaluation of static source code analyzers. The purpose of the evaluation was to determine their adequacy for use in developing realtime embedded software for aviation electronics where the use of development tools and methods is controlled by a federal regulatory agency. It describes the motivation for the evaluation, results, and conclusions.
Logical foundation for static analysis
Authors: Saïdi Hassen
Published: July 2008

Static analysis has emerged in recent years as an indispensable tool in software verification. Unlike deductive approaches to program verification, static analysis can only prove simple properties. Moreover, the myriad of static analysis tools employ specific techniques that target specific properties of specific programs. Static analysis holds the promise of complete automation, scalability, and handling larger classes of properties and larger classes of systems, but a significant gap exists between such a goal and current static analysis tools. We argue that a logical foundation for static analysis allows the construction of more powerful static analysis tools that are provably correct, extensible, and interoperable, and can guarantee more complex properties of complex systems. We address these challenges by proposing a tool-bus architecture that allows the combination of several static analysis tools and methods. The combination is achieved at the logical level using decision procedures that implement combination of theories. We discuss the application of such ideas to binary program analysis in the context of intrusion detection and malware analysis.
Gem #1: Limited types in Ada 2005 --- limited aggregates
Authors: Duff Bob
Published: July 2008

Ada Gem #1 --- Ada 2005 allows construction of limited objects via aggregates, thus gaining the advantage of the full coverage rules, which was previously available only for non limited types.
Holographic algorithms
Authors: Cai Jin-Yi
Published: July 2008

Leslie Valiant recently proposed a theory of holographic algorithms. These novel algorithms achieve exponential speed-ups for certain computational problems compared to naive algorithms for the same problems. The methodology uses Pfaffians and (planar) perfect matchings as basic computational primitives, and attempts to create exponential cancellations in computation. In this article we survey this new theory of matchgate computations and holographic algorithms.
Unconventional Mechanisms of Protein Transport to the Cell Surface of Eukaryotic Cells
Authors: Nickel Walter , Seedorf Matthias
Published: June 2008

The classical secretion of soluble proteins and transport of integral membrane proteins to the cell surface require transit into and through the endoplasmic reticulum and the Golgi apparatus. Signal peptides or transmembrane domains target proteins for translocation into the lumen or insertion into the membrane of the endoplasmic reticulum, respectively. Here we discuss two mechanisms of unconventional protein targeting to plasma membranes, i.e., transport processes that are active in the absence of a functional Golgi system. We first focus on integral membrane proteins that are inserted into the endoplasmic reticulum but that, however, are transported to plasma membranes in a Golgi-independent manner. We then discuss soluble secretory proteins that are secreted from cells without any involvement of the endoplasmic reticulum and the Golgi apparatus.
Robust Design of Terminal ILC with H∞ Mixed Sensitivity Approach for a Thermoforming Oven
Authors: Gauthier Guy , Boulet Benoit
Published: June 2008

This paper presents a robust design approach for terminal iterative learning control (TILC). This robust design uses the H∞ mixed‐sensitivity technique. An industrial application is described where TILC is used to control the reheat phase of plastic sheets in a thermoforming oven. The TILC adjusts the heater temperature setpoints such that, at the end of the reheat cycle, the surface temperature map of the plastic sheet will converge to the desired one. Simulation results are included to show the effectiveness of the control law.