bluuebunny/crossref_metadata_2025 huggingface dataset:
Reproductive ecology ofDryas integrifoliain the high Arctic semi-desert
Authors: Krannitz P. G.
Published: April 2008

Flowering and fruiting of Dryas integrifolia were studied at Igloolik and Pangnirtung to analyse the importance of variation in heliotropy and flower size to seed set and weight. In addition, peduncle elongation and seed plume length were also studied to analyse variation in seed dispersal characters. At both Igloolik and Pangnirtung, most Dryas flowers were not heliotropic throughout the course of the day, but in general, pointed towards the solar noon sun. Benefits to orienting toward the sun were warmer gynoecial temperatures, heavier seeds, and more insect visitation (though not percent seed set). Flowers varied in size from 1.2 to 2.7 cm in diameter and differed in size between plants. Even though larger flowers did not point towards the solar noon sun more than smaller flowers, they had heavier and proportionally more seeds. Variation in peduncle elongation suggests the potential for conservative dispersion when a flower has produced only a few propagules: flowers with fewer or no seeds had shorter stalks. Similarly, with good seed production, a bet hedging strategy is apparent: seeds located at the centre of the receptacle had much longer plumes than those at the perimeter of the seed head. All seed data were from Pangnirtung; the cold summer in 1986 at Igloolik resulted in a complete seed crop failure. Despite the adversity of the arctic climate, there are moderate summers during the lifetime of perennial plants such as D. integrifolia in which adaptations like those described in this study benefit the production of sexual offspring. Keywords: heliotropism, flower stalk elongation, basking insects, seed dispersal, insolation, bet hedging.
A comparison of the foliar nutrient status of elfinwood and symmetrically formed tall trees, Colorado Front Range, U.S.A.
Authors: Barrick Kenneth A. , Schoettle Anna W.
Published: April 2008

We tested the hypothesis of nutrient limitation in the trees of the alpine forest – tundra ecotone by comparing the foliar nutrient status of windsculpted elfinwood (also called krummholz) growing at the upper limit of tree success with symmetrically formed toll trees growing at the nearby timberline. The species investigated included Picea engelmannii (Parry) Engelmann, Abies lasiocarpa (Hooker) Nuttall, pinus flexilis james, and Pinus aristata Bailey. The foliar nutrient concentrations of the ecotone trees were similar to other healthy montane forests. Most of the significant differences in mean foliar nutrient concentrations between elfinwood and tall trees indicate lower concentrations in elfinwood trees. We found significantly lower mean phosphorus concentrations in Picea engelmannii and Abies lasiocarpa elfinwood compared with tall trees, but the mean nitrogen–phosphorus ratios were within the normal range. The foliar nutrient status of Pinus aristata elfinwood was similar to tall trees, while Pinus flexilis had considerably more significant differences in nutrient concentrations between the tree forms. Although there are many theoretical processes that could cause nutrient deficiencies at treeline, this study suggests that the elfinwood along the Colorado Front Range is not currently nutrient deficient. We discuss the potential differences in nutrient ecology between elfinwood and tall trees. Keywords: foliar nutrients, alpine ecotone, treeline, elfinwood, krummholz, conifer.
Tirisporella gen.nov., an ascomycete from the mangrove palm Nypa fruticans
Authors: Jones E. B. G. , Read S. J. , Moss S. T. , Alias Siti Alsysh , Hyde K. D.
Published: April 2008

Trisporella beccariana comb.nov. is redescribed from decomposing leaf petiole (or rachis) bases of Nypa fruticans recently collected in Malaysia and the Philippines. The superficial ascomata bear bitunicate asci with (3–)5(–7)-septate ascospores that are brown and verrucose, except for the prominent hyaline basal cell, and furnished with a distinctive apical appendage that arises from the spore wall. The ultrastructure of the fungus is contrasted with that of species of Corollospora and Corallicola, with particular reference to the mode of ascospore appendage formation. The species was originally described from a Sarawak collection as Sphaeria beccariana and later transferred to Melanomma and given the new name Melanomma cesatianum. Gibberidea nipae is a synonym. The recent collections were compared with type specimens. The fungus is not properly placed in Melanomma or Gibberidea or other known genera and a new genus Tirisporella is described. Keywords: Ascomycotina, ascospore appendage, mangrove fungus, taxonomy, ultrastracture.
Distribution of black spruce versus eastern larch along peatland gradients: relationship to relative stature, growth rate, and shade tolerance
Authors: Montague Timothy G. , Givnish Thomas J.
Published: April 2008

The relative abundance and performance of black spruce (Picea mariana) and eastern larch (Larix laricina) were quantified along fertility gradients in two peatlands in northern Wisconsin. We hypothesized that (i) the distribution of these two dominants should correspond to the portions of the gradient where each has an advantage in stature and (or) rate of height growth relative to its principal competitor; that (ii) larch should have a higher rate of height growth on wetter, more minerotrophic sites, based on the costs and benefits of its deciduous habit; and that (iii) spruce should be more shade tolerant and increase in abundance during succession. Our findings largely support these hypotheses, and (at the hydrologically stable site) provide the first circumstantial evidence for the competitive sorting of woody species along a natural gradient. The incongruity of interspecific differences in height and growth at one of the two sites is evidence for an historic change in the environment there, involving a shift in hydrology around 1925. Keywords: competitive sorting, deciduousness, evergreenness, Larix, Picea, Thuja.
Water pipe renewal using a multiobjective optimization approach
Authors: Nafi Amir , Werey Caty , Llerena Patrick
Published: April 2008

Water utilities ensure the delivery of water to consumers through a pressured network composed of several hydraulic components: reservoirs, pipes, valves, and pumps. A right maintenance policy that takes into consideration both technical and economic factors must be applied to enhance the hydraulic performance and reliability of the water network. With the help of a multiobjective approach based on a Pareto ranking and a modified genetic algorithm, we propose a decision support model that ensures the scheduling of pipe renewal according to available financial resources. The model is based on forecasting pipe failures and evaluating future maintenance costs. Two indexes are used to measure the hydraulic deficiency in the water network after a failure occurrence. They measure the undelivered water quantity and the number of unsupplied nodes when a considered pipe is unavailable during the peak demand period. Both indices permit classification of pipes and help identify critical ones. Feasible solutions are assessed according to economic and technical objectives. The model proposes solutions that enhance the reliability of a water distribution network and reduce failure occurrences, thus giving better satisfaction to consumers.
Experimental study on shear behavior of carbon-fiber-reinforced polymer reinforced concrete short beams without web reinforcement
Authors: Omeman Z. , Nehdi M. , El-Chabib H.
Published: April 2008

Recent literature emphasized the scarcity of information on the shear behavior of fiber-reinforced polymer (FRP) reinforced concrete short beams and the need to develop sufficient experimental data in this area. The present study responds to this need by conducting shear force testing on eight concrete short beams reinforced with carbon-fiber-reinforced polymer (CFRP) and four control concrete beams reinforced with steel. To ensure a shear failure, all tested beams were reinforced with only bottom longitudinal reinforcement and no web reinforcement was provided. The crack pattern, reinforcement strain, mode of failure, and shear strength and deflection of tested beams were studied. The influence of the shear span to effective depth ratio, a/d, beam effective depth, d, longitudinal reinforcement ratio, ρ, and concrete compressive strength, f ′con the shear behavior of CFRP-reinforced concrete short beams was examined. It was observed that the experimental parameters investigated had a significant effect on the shear strength and deflection of tested beams. It was also found that the strut-and-tie method more accurately predicts the shear strength of steel-reinforced concrete short beams than it does for similar CFRP-reinforced beams and, thus, needs to be modified to be applicable for reinforced concrete beams with FRP reinforcement.
Mechanical evaluation of asphalt–aggregate mixtures prepared with fly ash as a filler replacement
Authors: Tapkın Serkan
Published: April 2008

The objective of this study is to investigate the effect of fly ash as a filler replacement on the mechanical properties of asphalt–aggregate mixtures. Utilization of fly ash, which is the by-product of coal-fired power generation, is of great importance from an environmental and economical point of view. In this study, a dense bituminous mixture composed of calcareous aggregate was selected as the reference mixture. It was observed that there was a definite increase in Marshall stability and decrease in flow values, especially when calcareous filler was replaced by Soma-type fly ash, which was one of the three types of fly ashes used. The mechanical properties, namely elastic strain, elastic modulus, and permanent strain, of the asphalt mixtures were determined by carrying out fatigue tests with a UMATTA tester for three types of fly ashes, portland cement, lime, and control specimens. The changes in mechanical properties are important in the sense that they affect the behavior of asphalt concrete pavement under applied loads. This mechanism can be explained basically by bitumen extension. The fatigue life of fly ash specimens, especially Soma fly ash, was found to be considerably higher than that of calcareous filler specimens. Based on this study, it is demonstrated that fly ash can be used effectively in a dense-graded wearing course as a filler replacement.
Backcalculation of pavement layer moduli from falling weight deflectometer data using an artificial neural network
Authors: Sharma Sunil , Das Animesh
Published: April 2008

Efforts have been made in this paper to backcalculate the in situ elastic moduli of asphalt pavement from synthetically derived falling weight deflectometer (FWD) deflections at seven equidistant points. An artificial neural network (ANN) is used as a tool for backcalculation in this work. The ANN is observed to backcalculate layer moduli, both from normal as well as noisy deflection basins, with better accuracy compared with other software, namely, EVERCALC and ExPaS. EVERCALC is a backcalculation software downloaded from the Internet and ExPaS is a backcalculation algorithm developed in-house, based on a “search and expand” approach. Work have been extended further to develop ANN models that can predict a possible rigid layer at the bottom of the pavement and can directly predict the remaining life of the pavement without backcalculating the layer moduli. Finally, a reliability analysis is performed to quantify the performance of backcalculation using an ANN.
Seismic vulnerability assessment of multi-degree-of-freedom systems based on total input energy and momentary input energy responses
Authors: Vaseghi Amiri J. , Ghodrati Amiri G. , Ganjavi B.
Published: April 2008

In energy-based seismic evaluation and design, input energy as a seismic demand parameter and hysteretic energy are two important factors. Previous studies for seismic assessment and design based on energy approach have been generally limited to single-degree-of-freedom (SDOF) structures. The purpose of this paper is to find a suitable energy-based parameter for estimation of the damaging potential of ground motion in reinforced concrete frames of multi-degree-of-freedom (MDOF) systems. In this regard, 40 common reinforced concrete frames subjected to four different earthquakes have been analyzed. The results indicate that maximum momentary input energy is a more appropriate parameter than maximum total input energy for estimation of structural damage in short-duration earthquakes or those in which the major damage to structures happens within a short duration of ground motion. In addition, in earthquakes with a wide frequency range, the predominant period of ground motion in Fourier spectrum is shown to be the period corresponding to maximum input energy.
Shore-based photogrammetry of river ice
Authors: Bourgault Daniel
Published: April 2008

A simple and inexpensive method using a shore-based commercially available digital camera is developed to monitor river ice. The method was tested in a section of the St. Lawrence River, near Québec City, where tidal currents induce large changes in the ice distribution. It is shown that high resolution objective and quantitative information, such as the ice extent, spatiotemporal variability, and current fields, can be determined from the georectified images. The method proposed may provide an alternative to costly aerial surveys and other more sophisticated remote sensing techniques.
Integrated cost and schedule control in the Korean construction industry based on a modified work-packaging model
Authors: Kim Sangchul , Park Chanjeong , Lee Sangyoub , Son Jaeho
Published: April 2008

As a project control technique concept that provides a quantitative measure of schedule and cost information, the earned value (EV) model can evaluate work progress by identifying the potential delay and the cost overruns in a project, which is useful for controlling projects. The construction industry in Korea does not put this concept into practice, however, because it is poorly understood and because the construction practices in Korea are different from those in other industrialized countries. Most important is the fact that almost all the construction projects in Korea are controlled in accordance with the budget breakdown structure (BBS), which is less detailed than the cost breakdown structure (CBS), while those in the USA are managed through schedule control on the basis of the work breakdown structure (WBS). This is because most of the construction projects in Korea are generally contracted at a fixed price. This being the case, once the contract is awarded, the clients are no longer concerned with the cost of the project. This current construction practice based on the BBS rather than on the WBS has brought forth a limitation in terms of the use of the existing EV model in the domestic market. In this study, the EV model, which is suitable for the domestic market, is demonstrated. An integrated model of the WBS and CBS is then developed based on the modified work-packaging model. Finally, the developed model is integrated into the project management system (PMS) to verify its suitability and efficiency.
Dynamic testing of a corrugated steel arch bridge
Authors: Manko Zbigniew , Beben Damian
Published: April 2008

The paper presents the results and conclusions of dynamic load tests that were conducted on a highway bridge over the Gimån River in Sweden made of Super Cor corrugated steel plates (CSP), the first bridge of this type in Scandinavia. The critical speed magnitudes, dynamic coefficients, velocity vibration, and vibration frequency are determined in the paper. Conclusions drawn from the tests can be most helpful in the assessment of the behaviour of this type of corrugated plate – soil bridge. In consideration of the application of this type of structure in the case of small-to-medium span bridges, the conclusions from this research cannot yet be generalized to all types of such solutions. The application details with respect to all types of such bridge structures would require additional analysis (field and model tests and calculations) on the other types of soil–steel bridges.
Influence of transverse crack width on reinforcement corrosion initiation and propagation in mortar beams
Authors: Şahmaran Mustafa , Yaman İ. Özgür
Published: April 2008

This paper discusses the relationship between crack widths, chloride diffusivity, and corrosion rate of cracked mortar beams. Flexural loads are introduced to generate crack widths ranging from 29 to 390 µm. The specimens were subjected to accelerated corrosion by immersion in a 5% NaCl solution and a constant voltage of 12 V. In addition, salt ponding tests were conducted to determine the chloride ion transport properties. The results showed that as the crack width increased, the effective diffusion coefficient (corrosion initiation) and mass loss of steel reinforcing bars due to the accelerated corrosion (corrosion propagation) also increased. For crack widths less than about 135 µm, the effect of crack width on the effective diffusion coefficient and mass loss of steel reinforcing bars embedded in mortar specimens was found to be marginal when compared with the virgin specimens. Therefore, it was concluded that the effect of crack width on the corrosion initiation and propagation period was more pronounced when the crack width is greater than about 135 µm. Moreover, a significant amount of self-healing was observed for the cracks that have widths below 50 µm when subjected to the NaCl solution exposure.
Le biodiesel. I. Caractéristiques, atouts et limites — une synthèse
Authors: Nikiema J. , Heitz M.
Published: April 2008

Biodiesel, a fuel derived from animal or vegetable oil and fats, is presented in this paper. More specifically, its physico-chemical properties as well as the raw materials and existing standards are described. The advantages, limitations, and future of biodiesel are discussed. Biodiesel offers significant environmental advantages over petrodiesel: its combustion produces fewer atmospheric emissions of pollutants and greenhouse gases; in addition, it biodegrades easily and does not present a major risk during storage. On the other hand, the substitution of biodiesel for petrodiesel usually causes an increase in fuel consumption by engines. In addition, according to various estimates, the price of biodiesel is higher than that of petrodiesel. Nevertheless, biodiesel is easy to produce and, with the anticipated decline in stocks of fossil fuels, it constitutes an interesting substitute that should become increasingly used in the next decade.
Identical thermodynamical processes and the generalization of the Clausius inequality
Authors: Anacleto J , Ferreira J M , Anacleto A
Published: April 2008

We stress the advantages of heat and work reservoirs in the formalism of Thermodynamics and using an illustrative example show the need to reformulate the concepts of heat and work to avoid inconsistencies, namely, with regard to the Second Law. To deal with this problem, we use the concept of identical thermodynamical processes and obtain the condition for two such processes to be identical even when the system neighbourhood as a whole cannot be treated as a reservoir. The aforementioned concept is then applied to obtain a standardized definition of heat and work as well as a generalization of the well-known Clausius inequality. Finally, we return to the example given earlier to corroborate the effectiveness of our results.PACS Nos.: 05.70.–a, 44.90.+c, 65.40.Gr
Multiscale modeling of solids at the nanoscale: dynamic approach
Authors: Shiari B , Miller R E , Klug D D
Published: April 2008

One major class of multiscale models directly couples a region described with full atomistic detail to a surrounding region modeled using continuum concepts and finite element methods. Here, the development of a new dynamic approach to such coupled atomistic-continuum models is discussed with insight into the key ideas and features, with emphasis on fundamental difficulties involved in dynamic multiscale models. Simulations of nanoindentation in single crystals are performed to demonstrate the power of the developed method in capturing both long-range dislocation plasticity and short-range atomistic phenomena during single or cyclic loading without the computational cost of full atomistic simulations. The effects of several process variables are investigated, including system temperature and rate of indentation. The deformation mechanisms and the surface evaluation that occur during a series of single and cyclic indentation simulations are discussed. PACS Nos.: 81.07.–b or 73.22.–f
Note on magneto-hydrodynamic gravitational stability of a double fluids interface
Authors: Radwan Ahmed E , Dimian Mourad F
Published: April 2008

The magneto–gravitational stability of double-fluid interface is discussed. The pressure in the unperturbed state is not constant because the self-gravitating force is a long-range force. The dispersion relation is derived and discussed. The self-gravitating model is unstable in the symmetric mode m = 0 (m is the transverse wave number), while it is stable in all other states. The effects of the densities, the liquid-fluid radii ratios, and the electromagnetic force on the stability of the present model are identified for all wavelengths.PACS Nos.: 47.35.Tv, 47.65.–d, 04.40.–b
Free-forced convective boundary-layer flow of a biomagnetic fluid under the action of a localized magnetic field
Authors: Kafoussias N G , Tzirtzilakis E E , Raptis A
Published: April 2008

The problem of the two-dimensional steady and laminar free-forced convective boundary-layer flow of a biomagnetic fluid over a semi-infinite vertical plate, under the action of a localized magnetic field, is numerically studied. The dynamic viscosity of the biomagnetic fluid as well as its thermal conductivity is considered to be temperature-dependent whereas the magnetization of the fluid varies linearly with the magnetic field strength. The numerical solution of the coupled and nonlinear system of partial differential equations (resulting after the introduction of appropriate nondimensional variables) with boundary conditions describing the problem under consideration, is obtained by an efficient numerical technique based on the common finite difference method. Numerical calculations were carried out for the case of blood (Pr = 21) for different values of the dimensionless parameters entering into the problem, especially for the magnetic parameter Mn and the viscosity–temperature parameter Θr. The analysis of the obtained results, presented in figures, shows that the flow field is influenced by the application of the magnetic field, which could be interesting for medical and bioengineering applications. PACS Nos.: 44.20.+b, 44.25.+f, 44.27.+g, 47.15.Cb, 47.65.Cb, 47.63.–b, 47.90.+a
Charge and state population in dilute plasmas from beam-foil spectroscopy
Authors: Chantler C T
Published: April 2008

Beam-foil spectroscopy has a long history for determining charge state evolution, radiative decay lifetimes, spectral widths, and satellite structure. Many theoretical results predict a range of populations and state dependencies, but high resolution or a very large bandpass is normally required to test or investigate these. The current investigation has tested some key assumptions and models as applied to this relativistic regime, particularly for few-electron iron resonances and satellites. We conclude that there are two specific production mechanisms, one inside the target to low-n levels and one dominated by capture mechanisms at the exit of the foil, with particularly significant Rydberg cascades. Several systematics in high-precision measurements of these systems are discussed and quantified for the first time. The 2s–1s and 4f–2p satellites are explicitly investigated, and a dominant systematic is uncovered that is due to the variable location of spectral emission, downstream of the beam-foil target. PACS Nos.: 32.70.Jz, 34.10.+x, 52.20.Hv, 34.60.+z
Mansouri–Sexl framework for the high-speed Sagnac experiment
Authors: Sfarti Adrian
Published: April 2008

The Mansouri–Sexl theory is a well-known test theory of relativity. Mansouri and Sexl deal with a large number of experiments such as Michelson–Morley, Kennedy–Thorndike, Ives–Stilwell but leave out the very interesting Sagnac experiment. In the following paper we will argue for a novel way of detecting high-order effects in vacuo via an increased rotational speed re-enactment of the Sagnac experiment. We will show the presence of a large-value error term and will set the experimental conditions for detecting such a term. We will also show how the Saganac experiment can be used for the detection of light-speed anisotropy in the framework of the Mansouri–Sexl test theory. PACS No.: 03.30.+p
When a generalist becomes a specialist: patterns of red fox predation on roe deer fawns under contrasting conditions
Authors: Panzacchi M. , Linnell J. D.C. , Odden J. , Odden M. , Andersen R.
Published: April 2008

The red fox ( Vulpes vulpes (L., 1758)) functional response to roe deer ( Capreolus capreolus (L., 1758) fawn density was investigated in two Norwegian study areas characterized by a 26-fold difference in prey density and contrasting habitat characteristics. In the southern area, characterized by a fragmented agricultural landscape and high prey density, red fox consumption rates were closer to the specialist end in the specialist–generalist continuum of feeding habits. Conversely, in the northern area, dominated by boreal forest and with low prey density, the foxes displayed a type-III functional response typical of archetypal generalist predators. We suggest that differences in the predators’ feeding habits reflect differences in prey profitability, which was much higher in the southern area owing to higher prey density and to the openness of the landscape that both favour the hunting of roe deer fawns. Different functional responses produced different predation rates (25% for the southern area and 13% for the northern area) and different temporal patterns (highest predation risk for fawns born at the beginning or at the end of the birth season). Even though the understanding of a predator’s functional response is crucial for interpreting predation rates and patterns, much remains to be understood regarding its plasticity in different ecological settings. In the fawn–fox system, this might be the key factor in addressing unsolved questions regarding the adaptive value of reproductive synchrony as an antipredator strategy. Given the flexibility of the functional response and the resulting different impacts of predation with respect to birth synchrony, we suggest that reproductive synchrony evolved primarily in response to habitat seasonality and not as an antipredator strategy. Finally, our results contribute to the debate on the additive or compensatory nature of neonatal predation.
Dietary biomagnification of organochlorine contaminants in Alaskan polar bears
Authors: Bentzen T. W. , Follmann E. H. , Amstrup S. C. , York G. S. , Wooller M. J. , Muir D. C.G. , O’Hara T. M.
Published: April 2008

Concentrations of organochlorine contaminants in the adipose tissue of polar bears ( Ursus maritimus Phipps, 1774) vary throughout the Arctic. The range in concentrations has not been explained fully by bear age, sex, condition, location, or reproductive status. Dietary pathways expose polar bears to a variety of contaminant profiles and concentrations. Prey range from lower trophic level bowhead whales ( Balaena mysticetus L., 1758), one of the least contaminated marine mammals, to highly contaminated upper trophic level ringed seals ( Phoca hispida (Schreber, 1775)). We used δ15N and δ13C signatures to estimate the trophic status of 42 polar bears sampled along Alaska’s Beaufort Sea coast to determine the relationship between organochlorine concentration and trophic level. The δ15N values in the cellular portions of blood ranged from 18.2‰ to 20.7‰. We found strong positive relationships between concentrations of the most recalcitrant polychlorinated biphenyls (PCBs) and δ15N values in models incorporating age, lipid content, and δ13C value. Specifically these models accounted for 67% and 76% of the variation in PCB153 and oxychlordane concentration in male polar bears and 85% and 93% in females, respectively. These results are strong indicators of variation in diet and biomagnification of organochlorines among polar bears related to their sex, age, and trophic position.
MC1R variants correlate with thinhorn sheep colour cline but not individual colour
Authors: Loehr J. , Worley K. , Moe J. , Carey J. , Coltman D. W.
Published: April 2008

The melanocortin 1 receptor (MC1R) gene has provided a window on the evolution of colour polymorphisms. Recent studies have demonstrated associations between MC1R and melanism in a number of wildlife species. Thinhorn sheep ( Ovis dalli Nelson, 1884) are a possible species to test for association between MC1R polymorphisms and melanism. Across their range the pelage colour of thinhorn sheep intergrades between all white phenotypes to very dark phenotypes. Most thinhorn sheep are white; however, there is a 1200 km cline from light to dark sheep that occurs over three genetically distinct polymorphic populations. We sequenced the entire MC1R gene from 40 individuals across the range of thinhorn sheep. We found a single nucleotide polymorphism in MC1R at base pair position 921 that coincided with the geographic cline. However, at the individual level we found no relationship between individual melanism and genotype.
Effect of forest management on a rare habitat specialist, the Bicknell's Thrush (Catharus bicknelli)
Authors: Chisholm S. E. , Leonard M. L.
Published: April 2008

Forest dwelling birds with narrow habitat preferences may be vulnerable to habitat changes from forest management. The Bicknell’s Thrush ( Catharus bicknelli (Ridgway, 1882)), a rare habitat specialist, occupies dense regenerating forest, including stands managed for timber. However, little is known of the impact of various forestry practices on Bicknell’s Thrush abundance. The purpose of our study was to determine how Bicknell’s Thrush abundance varied across the stages of a managed forest and to determine if abundance was affected by precommercial thinning, a practice that reduces stem density. Bicknell’s Thrush was most abundant in stands that were regenerating after being clear-cut 11–13 years earlier and of sufficient height and stem density to undergo thinning. Thrush abundance declined following thinning and was positively related to the amount of unthinned area remaining in the stand. Over all stand types, thrush abundance increased with increasing elevation and with the density of stems between 5 and 10 cm in diameter, but decreased with increasing amounts of bare ground. The results of this study suggest that Bicknell’s Thrush may benefit from the early successional habitat associated with managed forests, but may be negatively affected by treatments such as precommercial thinning that reduce stem densities.
Population size, catchment area, and sex-influenced differences in autumn and spring swarming of the brown long-eared bat (Plecotus auritus)
Authors: Furmankiewicz J.
Published: April 2008

Swarming by bats is defined as intense autumnal flight activity in and near underground hibernation sites and is considered to be associated with mating, but this behaviour may also serve to allow bats to assess potential hibernacula. To test if swarms consist of resident bat populations from the surrounding area or transitional bat populations migrating between summer and winter areas, I measured activity patterns and the distribution of day roosts of swarming brown long-eared bats ( Plecotus auritus (L., 1758)) at two abandoned mines in southwestern Poland. Swarming occurred from mid-August to mid-October, and also in March and April. The maximum population of swarming bats was estimated to be about 500 individuals. The sex ratio was male-biased and was more skewed in spring than in autumn. Bats frequently travelled to the swarming site from day roosts as far away as 31.5 km. They usually stayed for several hours before returning to a day roost without visiting other hibernacula. Males roosted closer to the swarming site and visited it more frequently than females, consistent with increased mating attempts. My results suggest that swarming sites are hot spots for populations resident in the surrounding area. They likely play an important role in gene flow and facilitate mating among bats from spatially isolated populations.
Parasite-mediated allochthonous input: Do hairworms enhance subsidized predation of stream salmonids on crickets?
Authors: Sato T. , Arizono M. , Sone R. , Harada Y.
Published: April 2008

Energy and nutrients flow in diverse pathways across heterogeneous landscapes and tightly link the discrete food webs in local habitats. However, parasitism that enhances allochthonous resource input has not been previously documented. In a well-known example of parasite manipulation of host behaviour, crickets infected by mature hairworms (Nematomorpha) seek and jump into water when the worms reach the free-living stage. We found that a large number of trout (22%–61%), an aquatic predator, preyed on camel crickets (genera Diestrammena Brunner von Wattenwyl, 1888 and Tachycines Adelung, 1902) in September in five Japanese mountain streams where this host–parasite system exists. Trout (Kirikuchi charr, Salvelinus leucomaenis japonicus (Oshima, 1961); red-spotted masu salmon, Oncorhynchus masou ishikawae Jordan and McGregor, 1925) that preyed on crickets frequently ingested hairworms, whereas trout that did not prey on crickets did not ingest hairworms. Our results strongly suggest that hairworms enhance stream salmonid predation on camel crickets. This is the first documentation of parasitism enhancing allochthonous resource input in nature. Trout ingested a greater mass of crickets than other prey species in September, and this energy influx may play an important role in food-web dynamics in headwater streams.
Spatial and temporal patterns of territory use of male California sea lions (Zalophus californianus) in the Gulf of California, Mexico
Authors: Robertson Kathy L. , Runcorn C. W. , Young Julie K. , Gerber Leah R.
Published: April 2008

Little is known about the spatial distribution patterns of territory use throughout the breeding season and the potential influence of these patterns on male behavior and fitness for California sea lions ( Zalophus californianus (Lesson, 1828)). We used empirical data from behavioral observations to document the distribution of 1271 territories during the 2004–2006 breeding seasons at three breeding colonies in the Gulf of California, Mexico. Territories were depicted as circular objects and overlaid over one another in ArcINFO®, separated by island and year. Areas with consistent overlap in territory use were identified among years. Territory boundaries and locations were spatially distinct within breeding seasons and at each of the breeding colonies. Males occurring in these areas were partially influenced by island, year, territory size, number of females, aggressive interactions, and distance to nearest neighbor (best fitting model — AIC = 1273.09, ωi= 0.99). However, the best model only accounted for 30% of the variation, indicating that other variables are needed to explain the occurrence of these “hot spots”. Territory site selection, therefore, may be influenced by extrinsic factors under which female choice may be operating resembling a lek-like mating system.
Selection of lake habitats by waterbirds in the boreal transition zone of northeastern Alberta
Authors: Found C. , Webb S. M. , Boyce M. S.
Published: April 2008

We examined habitat characteristics associated with presence or absence of 16 waterbird species on 113 lakes during 2001–2006. We found that piscivorous species such as pelicans, loons, and mergansers were found on fish-bearing lakes, while birds that typically nest in emergent vegetation (e.g., coots, grebes) strongly preferred water bodies with moderate to high levels of emergent macrophytes. The presence of a riparian buffer was important for loons and several species of waterbird that nest on the backshore. Moderate to deep lake depth and high water clarity also were important for some species and likely associated with hunting habits and (or) fish availability. Breeding-occurrence models were developed for a few conspicuous species that could be sampled using aerial surveys. Surprisingly, changes in water levels were not important predictors for most species, and associations between waterbirds and high levels of recreational activity were unexpected. Common Loon ( Gavia immer (Brunnich, 1764)) and Great Blue Heron ( Ardea herodias L., 1758) were most sensitive to anthropogenic activities, with fewer of these species detected on lakes with more disturbed shorelines.
Causes and consequences of distribution patterns in a migratory songbird across its geographic range
Authors: Mattsson B. J. , Niemi G. J.
Published: April 2008

The ideal distribution hypothesis states that territorial animals identify habitats with ideal habitat suitability and alter their settlement patterns accordingly. This hypothesis assumes no cost of migrating to a more profitable patch once the current one becomes less profitable. Another underlying assumption is that individuals only use current information while deciding where to breed. To evaluate these assumptions and resultant alternative hypotheses, we studied Ovenbird ( Seiurus aurocapilla (L., 1766)) territories during 2000–2001 in six northern hardwood tracts within a landscape composed of wetlands, regenerating stands, small farms and roads. We incorporated data from our own study and from published studies across the Ovenbird geographic range, using an information-theoretic approach. Contrary to the ideal distribution hypothesis, Ovenbird territory density increased with upland openings, but density was similar across clearcut-edge-distance and forest-thinning categories. Relationships between reproduction and territory density were uncertain and therefore provided little evidence against the ideal free distribution hypothesis, but there was some evidence in favor of the alternative costly migration and ideal dominance hypotheses from the analysis of our own data and the meta-analysis, respectively. Finally, territories became denser when fecundity and pairing success were high during the previous year, and this supports the public information hypothesis. We recommend using measures of reproductive success in conjunction with territory density when assessing population status.
Effects of food restriction on growth, energy allocation, and sexual size dimorphism in Yarrow’s Spiny Lizard, Sceloporus jarrovii
Authors: Cox Robert M. , Barrett Michele M. , John-Alder Henry B.
Published: April 2008

Evolutionary biologists often view sexual size dimorphism (SSD) as a fixed genetic consequence of sexually antagonistic selection, but the actual magnitude of SSD may often be strongly dependent upon proximate environmental factors. Sexual differences in growth rate lead to male-biased SSD in wild populations of Yarrow’s Spiny Lizard ( Sceloporus jarrovii Cope, 1875), yet both sexes grow at similar rates under controlled laboratory conditions. We hypothesized that male-biased SSD in S. jarrovii reflects an obligatory sexual difference in energy allocation to growth versus competing functions, but that an ad libitum diet provides an energy surplus which overwhelms this sex-specific energetic trade-off. To test this hypothesis, we reared juveniles under high (3 crickets/d) and low (1 cricket/d) food availabilities. Food restriction dramatically reduced growth in both sexes but did not differentially affect growth of females relative to males. Food consumption did not differ between sexes, but males grew slightly faster than females at both levels of food availability, indicating a greater fractional allocation of available energy to growth. By contrast, females had larger fat bodies than did males, particularly under food restriction. This sexual difference in energy allocation to storage could explain the slightly higher growth rate of males relative to females.
SINGULAR FERMI SURFACES I: GENERAL POWER COUNTING AND HIGHER DIMENSIONAL CASES
Authors: FELDMAN JOEL , SALMHOFER MANFRED
Published: April 2008

We prove regularity properties of the self-energy, to all orders in perturbation theory, for systems with singular Fermi surfaces which contain Van Hove points where the gradient of the dispersion relation vanishes. In this paper, we show for spatial dimensions d ≥ 3 that despite the Van Hove singularity, the overlapping loop bounds we proved together with E. Trubowitz for regular non-nested Fermi surfaces [J. Stat. Phys.84 (1996) 1209–1336] still hold, provided that the Fermi surface satisfies a no-nesting condition. This implies that for a fixed interacting Fermi surface, the self-energy is a continuously differentiable function of frequency and momentum, so that the quasiparticle weight and the Fermi velocity remain close to their values in the noninteracting system to all orders in perturbation theory. In a companion paper, we treat the more singular two-dimensional case.
General Motors China versus Chery: Disputes Over Intellectual Property Rights
Authors: Liu Shengjun , Fernandez Juan Antonio
Published: April 2008

Chery, a Chinese domestic car maker, launched a new mini car model, the QQ in July 2003. This was several months earlier than the planned launch date for General Motor (GM)'s new mini car, the Chevrolet Spark. The QQ looked very similar to the Chevrolet Spark but was priced much cheaper. GM claimed that the Chery QQ was a knockoff of the Matiz, a model owned by GM Daewoo. To make matters worse for GM, Chery was aggressively expanding into other countries where GM had a presence. The case was tailored for illustrating the IPR challenges for multinationals to do business in China.
Amul India: A Social Development Enterprise
Authors: Chawla Harish
Published: April 2008

Amul initiated as an experiment in two villages, collecting 250 kg of milk per day. As the cooperative expanded its branches over the course of its 50-year journey, Amul boasts of more than six million kilograms of milk collection daily.

What had initiated as a process of liberation from the Dairy King, brought a revolutionary transformation across the country. This case provides a vivid example of how a cooperative can become the catalyst for social change and rural development. This case takes us through the journey of Amul, from its dawn period when it was attempting to take root, through its progression along the enterprise life stages and the associated challenges. Insights into the quality of leadership and the farmer/management relationships are its defining characteristic.

The Amul Model narrowed the gap between the producer and the consumer, connecting the dairy farmer to the consumer through its organic network. The success of this model ignited interest across India, where this model was replicated, in essence leading to the White Revolution. The case provides sufficient insights and learnings to develop a framework to comprehend the basic essence of a prosperous social enterprise — factors that make it successful. It is this learning that this case desires to impart to its readership, enhancing interest in this rather lively subject of social enterprises.
The Alang Ship-breaking Yard
Authors: Thomas Manoj T.
Published: April 2008

The case deals with the issue of environmental dumping in the poorer nations by more advanced nations. The trigger for the case is the sending back of the French naval ship Clemenceau from Indian coasts on the grounds that it contained prohibited environmentally hazardous materials like asbestos. The issue raised intense debates both in the public domain and the legal courts. Environmentalists, who brought the news in the public domain, sought legal intervention and argued in the public media. While the ship was sent back to France following the decision by France's highest administrative court, it raised questions about the entire ship breaking business. Alang, where the ship was initially supposed to be broken down, had seen an increase in business owing to the relatively cheap labour and less stringent environmental legislations compared to the established ship breaking centres in Europe and China. As poorer countries with even less regulated ship breaking centres, such as Bangladesh and Pakistan entered the fray, Alang had seen a decline in business. Ship breaking in Alang contributes to employment and the sending away of Clemenceau was seen by many supporters of ship breaking at Alang as lost opportunity for reviving the stagnating business at Alang. Others, however, saw it as an opportunity for Alang to improve environmental compliance and to introduce new technologies in ship breaking so that it can be sustainable in the long run. The case presents these different perspectives and tries to demonstrate the decision dilemma faced by a policy maker or regulator.
Human Resource Driven Turnaround at North Delhi Power Limited: Transition from a Public Utility to a Private Enterprise
Authors: Bhatnagar Jyotsna , Saini Debi
Published: April 2008

The case illustrates how a public sector utility entity with almost no human resource (HR) system in place went on the road of transformation and learning. The case documents areas of transformation from an archaic personnel architecture towards institutionalization of strategic HR system. From file maintenance to strategic partnership, the journey of HR along with top management support and line management involvement is mapped throughout the case. The establishment of a psychological contract acted as the foundation, resulting in commitment and faster adaptation to change. Organizational learning took roots with systemic changes starting from the external customer and later in the internal customer. The role of HR as a strategic partner in this transformation was exemplified as HR enjoyed voice and space at the board level of the organization. This case is useful for showing how internal change agents and the active partnership of HR can lead to greater commitment than compliance with top management directives.
INSIDER TRADING AND VOLUNTARY DISCLOSURE
Authors: GRÉGOIRE PHILIPPE
Published: April 2008

We set up a model to study the voluntary disclosure of information by insiders of publicly traded companies. We consider a trading framework as in [14] with many assets and one insider per asset. There is one discretionary liquidity trader who can allocate his trades across the different assets and many noise traders who trade with equal intensity in all assets. Before trade begins, insiders can disclose information in order to attract the discretionary liquidity trades. We show that if the level of noise trading is above a certain threshold, then there is an equilibrium where all insiders do not disclose any information. Below this threshold, equilibria are such that some information is always revealed by insiders. We also find that the greater the number of assets, the smaller the intensity of noise trading must be in order to induce insiders to disclose some information, and we find that insiders reveal all their information when the intensity of noise trading approaches zero.