bluuebunny/crossref_metadata_2025 huggingface dataset:
Pattern of flow around filter-feeding structures of immature Simulium bivittatum Malloch (Diptera: Simuliidae) and Isonychia campestris McDunnough (Ephemeroptera: Oligoneuriidae)
Authors: Braimah Stephen A.
Published: April 2008

Filter feeding in immatures of Simulium bivittatum and Isonychia campestris is characterized by low Reynolds number (Re) (i.e., Re = 0.02–3.9). Scaled-up models of portions of filters towed through Canola oil revealed that capture of small particles occurs in the viscous boundary layer closest to the ray. Adhesion of such particles is enhanced by the reduction of velocity in the viscous layer with consequent increase in time for transit of particles in the filters. There was very little flow between adjacent rays of filters of larvae of S. bivittatum up to Re value of 0.49 (real life equivalent of 10.0 cm/s) and Re of 1.39 (17.5 cm/s) for nymphs of I. campestris because of boundary layer thickness. Microtrichia of S. bivittatum functioned as a virtually solid wall with no flow between adjacent microtrichia up to Re of 3.98 (80.0 cm/s) and for I. campestris up to Re of 7.79 (100.0 cm/s).
Differential habitat use and sexual segregation in the Central Arctic caribou herd
Authors: Jakimchuk R. D. , Ferguson S. H. , Sopuck L. G.
Published: April 2008

Distribution of the Central Arctic caribou herd is characterized by segregation of the sexes and different habitat preferences by male and female caribou over most of the annual cycle. During all periods except late winter and postcalving, females showed a more northern distribution than did males. Females used riparian habitats less than availability and were generally farther from major river valleys than expected during all seasons except late winter. In contrast, males preferred riparian habitats from late winter to calving and were generally found closer to river valleys than were females from late winter to August dispersal. During the spring and calving periods near the coast females preferred sedge meadow and used riparian habitat less than availability whereas males preferred riparian and tussock tundra and used sedge meadow less than availability. It is theorized that sexual segregation and differential habitat use reflect predator avoidance strategies of females with calves and optimal foraging by adult males.
Correlates and consequences of coloniality in great blue herons
Authors: Simpson Keith , Smith James N. M. , Kelsall John P.
Published: April 2008

Sixty percent of the breeding great blue herons (Ardea herodias) in a colony at Pender Harbour, British Columbia, were individually marked to test three hypotheses concerning the benefits of colonial breeding. (i) Most herons fed near the site of the colony, but neighbours or members of a pair did not tend to choose adjacent feeding sites, as predicted by the information center hypothesis. Food supply was predictably distributed in time and space, and birds that did most of their feeding outside Pender Harbour bred less successfully than locally feeding birds. (ii) Nests that failed because of predation were nearer to the edge of the colony in 1978 but not in 1979. The colony was abandoned in 1980 after 2 years of high predation. Predation may, therefore, select for colonial breeding in herons, but heavy predation may force colony abandonment. (iii) Most herons chose new nest sites and new mates each year. The colony site may therefore serve as an assembly site for mate finding. Mate finding and avoidance of predation are therefore more likely to explain coloniality in great blue herons than are advantages associated with finding food.
The flight directionality of honeybees foraging on real and artificial inflorescences
Authors: Kipp Larry R.
Published: April 2008

An examination of the flight directionality, the change in direction between arrival and departure, of Apis mellifera (Apidae) workers foraging on artificial inflorescences and on inflorescences of Echinops sphaerocephalus L. (Compositae) is reported. Thirty-seven circular, artificial inflorescences, each with three feeding tubes separated by 120° located on the perimeter were used. At the beginning of each visit all tubes contained 2 ± 0.2 μL of 1.2 M sucrose solution. Bees locating the tubes would probe one or more of them, then depart to another artificial inflorescence and repeat the foraging sequence. Changes in flight directionality were generated during within-inflorescence locomotion and not after feeding had ceased. Directionalities of bees that circled a second time around these inflorescences were indistinguishable from bees departing the same locations prior to completing a single cycle. Hence, the directionality of bees visiting tubes in the sequence 1-2-3-1, 1-2-3-1-2, or 1-2-3-1-2-3 were indistinguishable from the directionality of bees visiting tubes in the sequence 1, 1-2, or 1-2-3, respectively. The direction faced by bees while probing the final tube or floret (last-faced direction) was most often the departure direction; thereafter, bees flew ahead to the nearest inflorescence. An energetic analysis of the artificial inflorescence study showed that directionality was independent of nectar uptake rates. The experiment using real inflorescences, some of which had been enriched with ca. 10 μL of 1.2 M sucrose solution, confirmed that directionality was generated during within-inflorescence locomotion and that the last-faced directon was the most frequent departure direction; furthermore, changes between the last-faced and departure directions were independent of nectar uptake. Evident in the search pattern of honeybees were the following: (i) a forward-moving tendency while on inflorescences, (ii) a departure decision, (iii) departure in the last-faced direction, and (iv) minimum deviation from the last-faced direction when flying directly to the next inflorescence. Although bees tend to move in a forward-facing direction during all movement phases, the floral architecture facilitates or induces turning. The extent of the turn is limited by the bees decision to depart. It is concluded that directionality is an epiphenomenon resulting from interactions among floral architecture, bee locomotion, floral nectar content, and the bee's departure decision. Memory of the arrival direction is not required.
Distribution and abundance of tintinnids in the Quoddy Region of the Bay of Fundy
Authors: Middlebrook K. , Emerson C. W. , Roff J. C. , Lynn D. H.
Published: April 2008

The seasonal cycle of tintinnid species compositions, numerical abundance, and average lorica oral diameter was examined along a nearshore–offshore transect in the Quoddy Region of the Bay of Fundy. Among 27 species identified, Stenosemella nivalis was most abundant. Highest abundances of tintinnids were observed near the surface; hyaline forms dominated near the surface while agglutinated forms were predominant in subsurface waters. Maximum abundances of 1.8 × 108 and 9.0 × 106 cells/m2 were observed at near- and off-shore stations, respectively, in summer. Hyaline tintinnids were more numerous in midsummer and at the offshore site, possibly because of the necessity of a sedimentary phase in the life cycle of agglutinated forms. The seasonal decrease in the lorica oral diameter of tintinnids was paralleled by a decrease in average cell volume of phytoplankton. Annual tintinnid productivity was estimated as 250 kJ/m2 in Passamaquoddy Bay (nearshore) and total productivity from May to October was 34 kj/m2 in the lower Bay of Fundy (offshore). We conclude that tintinnid ciliates are an important trophic intermediate in the planktonic food web because of their high productivity and their ability to feed on the small, highly productive phytoplankton.
Variation in weight and composition of Red-winged Blackbird eggs
Authors: Muma Katherine E. , Ankney C. Davison
Published: April 2008

To investigate variation in egg weight and composition we collected and analyzed 38 Red-winged Blackbird (Agelaius phoeniceus) eggs. The composition of Red-winged Blackbird eggs was very similar to that reported for Brown-headed Cowbird (Molothrus ater) eggs. Egg weight is a good predictor of total energy (kJ) in blackbird eggs as those two variables were highly correlated (r2 = 0.66). Weight of Red-winged Blackbird eggs did not change over the breeding season.
Species richness and abundance of Pselaphidae (Coleoptera) in old-growth and 40-year-old forests in New Hampshire
Authors: Chandler Donald S.
Published: April 2008

Species richness and abundance of Pselaphidae, the ant-like litter beetles, are compared between two mixed deciduous–conifer forest sites: one old growth, and the other cut in 1944–1945. Comparisons were based on forest litter samples and flight intercept trap collections obtained through the season. Twelve species were collected at the old-growth site, and nine at the cut site. The pselaphid fauna of the sites is compared using coefficient of community and percent similarity. The coefficient of community is similar at both sites based on litter samples, while the percent similarity is low in leaf litter samples and moderate in rotten wood samples. Rotten wood species were at similar densities within a habitat at both sites, but were more numerous in flight intercept traps at the old-growth site because of the greater amount of rotting wood available. Flight activity is suspected to be tied to optimum weather conditions when adults seek their patchily distributed habitat. Eutyphlus schmitti could be used as an indicator species for undisturbed forests in the Northeast. Maximum species richness for Pselaphidae is probably reached after the forest achieves a steady state in biomass accumulation, a period of 100–120 years after clear-cutting operations.
A comparative morphological study of the Stutzzelle (support cell) in the phylum Acanthocephala
Authors: Gee Randall J.
Published: April 2008

The location and structure of the Stutzzelle is reconstructed, using light microscopy, in 12 species representing the three classes of the phylum Acanthocephala, using serial transverse, sagittal, and longitudinal sections of adult worms. A basic pattern with three different variations, one for each class, is described along with family and generic variations in the Eoacanthocephala and Paleacanthocephala. The association of the Stutzzelle with the apical and neck sense organs in those species with these organs is described. Its absence from one species without neck and apical sense organs is discussed. The variable number of nuclei in the Stutzzelle in the three classes is described with the Eoacanthocephala having a binucleate, the Paleacanthocephala, a tri- or bi-nucleate, and the Archiacanthocepala, a pentanucleate Stutzzelle. The apical sense organs in the Archiacanthocephala, especially double apical sense organs in Moniliformis moniliformis, and the absence of apical sense organs in the Eoacanthocephala and Paleacanthocephala are described. The location of the Stutzzelle on the inner surface of the dorsal wall of the proboscis receptacle is described in the Eoacanthocephala and Paleacanthocephala. The location of the Stutzzelle in the Archiacanthocephala is redescribed as dorsal instead of ventral, making the location consistent in the phylum Acanthocephala.
Abomasal nematodes from three Norwegian wild reindeer populations
Authors: Bye Karstein
Published: April 2008

Three separate populations of wild reindeer (Rangifer tarandus tarandus L.) in Norway were examined for the presence of abomasal nematodes. The following six species were recorded: Ostertagia grühneri, Skrjabinagia arctica, Trichostrongylus axei, Teladorsagia circumcincta, Teladorsagia davtiani, and Nematodirus tarandi. Ostertagia grühneri dominated both in prevalence and intensity of infection. Teladorsagia davtiani occurred in only one of the populations investigated, and N. tarandi was found in calves only. Reindeer and sheep grazed the same areas, but no evidence of transfer of parasites from sheep to reindeer was found. All 72 adult reindeer and 10 calves examined during February–April harboured adult abomasal nematodes. The mean intensity of abomasal nematodes was highest in the population with the highest density of reindeer. Reindeer from this population were in poor physical condition. The influence of abomasal nematodes on life-history parameters of the host population is discussed.
A study of the behavior of Dall's porpoise (Phocoenoides dalli) in the Johnstone Strait, British Columbia
Authors: Jefferson Thomas A.
Published: April 2008

The behavior of Dall's porpoise was studied in the western Johnstone Strait, British Columbia, during the summer of 1984. Observations and theodolite trackings were made from a cliff-top observation point on West Cracroft Island. Dall's porpoise was the second most common marine mammal in the study area, being seen on 63% of the days, and it was reported to be a year-round resident of the Strait. Three types of surfacing behavior were observed, with slow rolling occurring in 97% of the sightings. Swimming speed of slow rolling porpoises was 5.1 ± 0.83 (SD) km/h (n = 18). Dives during travel averaged 35.9 ± 26.52 (SD) s (n = 10). Deep vertical dives lasted 2 to 4 min for adults and up to 2 min for calves, and were presumed to be associated with feeding. Westward movement predominated. Dall's porpoises usually showed no obvious reaction to resident killer whales, but apparently swimming speed increases when killer whales are within 2 km. Group sizes ranged from one to over five animals (mean size = 2.6 ± 1.05 (SD), n = 68). Groups that included calves tended to be larger than adult-only groups. Neither direction of travel nor time of day were significantly related to group size. The population appears to contain a high percentage of cow–calf pairs, and this suggests that the study area may be used as a calving area during the summer.
Winter food habits and foraging behaviour of fishers (Martes pennanti) and martens (Martes americana) in southeastern Manitoba
Authors: Raine R. Michael
Published: April 2008

A tracking study of fishers, Martes pennanti, and American pine martens, Martes americana, conducted over two winters in southeastern Manitoba showed that both species preyed heavily on snowshoe hares, Lepus americanus, during a period of hare abundance. Fishers had an 84.3% frequency occurrence (n = 159) of hares in their scats, while martens had a frequency occurrence of 58.9% (n = 107). Martens had a higher frequency of microtincs and red squirrels, Tamiasciurus hudsonicus, in their diets than did fishers. This difference was reflected in the foraging behaviour of the two species, with martens exhibiting more subnivean and arboreal behaviour than fishers.
First report of Loma sp. (Microsporida) in juvenile coho salmon (Oncorhynchus kisutch) from Vancouver Island, British Columbia
Authors: Magor Brad G.
Published: April 2008

A species of Loma Morrison and Sprague, 1981 (Microsporida) was found in gills of smolt of Oncorhynchus kisutch from a hatchery on Vancouver Island, British Columbia. Prevalence of cysts was 28%. Maximum intensity was 84 cysts per fish. Histopathologic response of gills to cysts was minimal and localized where observed. This is the first report of a species of Loma in wild or captive fishes in western Canadian waters. The significance of its presence here is considered in light of a recent Loma epizootic in Alaska.
Coyote adult–pup interactions in the first 3 months
Authors: Fentress J. C. , Ryon J. , McLeod P. J.
Published: April 2008

We examined the distribution of aggressive and affiliative interactions between four adult coyotes (two females and two males) and a litter of pups, 1 to 3 months of age. While most interactions were affiliative, encounter types were distributed differently among different adult–pup group pairs, with significant main effects plus two- and three-way statistical interactions involving (i) individual adults, (ii) initiator, and (iii) quality of encounters. From the outset of our study, pups treated adults differently, even though the total number of interactions with different adults was similar. The most marked differences were between the mother and nulliparous female, with the former being highly affiliative and the latter highly aggressive. The males were mostly affiliative. In spite of the aggressive initiations and rebuffs by the nulliparous female, the pups persisted in their affiliative initiations towards her. These data reflect important socialization processes and contextual factors that may contribute to patterns of group organization observed in the field.
Complex Genetics of Obesity in Mouse Models
Authors: Pomp Daniel , Nehrenberg Derrick , Estrada-Smith Daria
Published: April 2008

Traits related to energy balance and obesity are exceptionally complex, with varying contributions of genetic susceptibility and interacting environmental factors. The use of mouse models has been a powerful driving force in understanding the genetic architecture of polygenic traits such as obesity. However, the use of mouse models for analysis of complex traits is at an important crossroad. Genome-wide association studies in humans are now leading to direct identification of obesity genes. In this review, we focus on three areas representing the current and future roles of mouse models regarding genetics of complex obesity. First, we summarize increasingly powerful ways to harness the strength of mouse models for discovery of genes affecting polygenic obesity. Second, we examine the status of using a systems biology approach to dissect the genetic architecture of obesity. And third, we explore the effects of recent findings indicating increasing levels of complexity in the nature of variation underlying, and the heritability of, complex traits such as obesity.
Functional interaction of regulatory factors with the Pgc-1α promoter in response to exercise by in vivo imaging
Authors: Akimoto Takayuki , Li Ping , Yan Zhen
Published: April 2008

Real-time optical bioluminescence imaging is a powerful tool for studies of gene regulation in living animals. To elucidate exercise-induced signaling/transcriptional control of the peroxisome proliferator-activated receptor-γ coactivator-1α ( Pgc-1α) gene in skeletal muscle, we combined this technology with electric pulse-mediated gene transfer to cotransfect the Pgc-1α reporter gene with plasmid DNA encoding mutant/deletion forms of putative regulatory factors and, thereby, assess the responsiveness of the promoter to skeletal muscle contraction. We show that each of the myocyte enhancer factor 2 sites on the Pgc-1α promoter is required for contractile activity-induced Pgc-1α transcription. The responsiveness of the Pgc-1α promoter to contractile activity could be completely blocked by overexpression of the dominant-negative form of activating transcription factor 2 (ATF2), the signaling-resistant form of histone deacetylase (HDAC) 5 (HDAC5), or protein kinase D (PKD), but not by HDAC4. These findings provide in vivo evidence for functional interactions between PKD/HDAC5 and ATF2 regulatory factors and the Pgc-1α gene in adult skeletal muscle.
Substance P enhances NF-κB transactivation and chemokine response in murine macrophages via ERK1/2 and p38 MAPK signaling pathways
Authors: Sun Jia , Ramnath Raina Devi , Zhi Liang , Tamizhselvi Ramasamy , Bhatia Madhav
Published: April 2008

The neuropeptide substance P (SP), as a major mediator of neuroimmunomodulatory activity, modulates diverse functions of immune cells, including macrophages. In the current study, we focused on the yet uncertain role of SP in enhancing the inducible/inflammatory chemokine response of macrophages and the signaling mechanism involved. We studied the effect on the murine monocyte/macrophage cell line RAW 264.7 as well as isolated primary macrophages. Our data show that SP, at nanomolar concentrations, elicited selective chemokine production from murine macrophages. Among the chemokines examined, macrophage inflammatory protein-2 and monocyte chemoattractant protein-1 are two major chemokines that were synthesized by macrophages in response to SP. Furthermore, SP treatment strongly induced the classic pathway of IκB-dependent NF-κB activation and enhanced DNA binding as well as transactivation activity of the transcription factor. SP-evoked transcriptional induction of chemokines was specific, since it was blocked by treatment with selective neurokinin-1 receptor antagonists. Moreover, SP stimulation of macrophages activated the ERK1/2 and p38 MAPK but not JNKs. Blockade of these two MAPK pathways with specific inhibitors abolished SP-elicited nuclear translocation of phosphorylated NF-κB p65 and NF-κB-driven chemokine production, suggesting that the two MAPKs lie in the signaling pathways leading to the chemokine response. Collectively, our data demonstrate that SP enhances selective inflammatory chemokine production by murine macrophages via ERK/p38 MAPK-mediated NF-κB activation.
Mechanism of estrogen-mediated intestinal protection following trauma-hemorrhage: p38 MAPK-dependent upregulation of HO-1
Authors: Hsu Jun-Te , Kan Wen-Hong , Hsieh Chi-Hsun , Choudhry Mashkoor A. , Schwacha Martin G. , Bland Kirby I. , Chaudry Irshad H.
Published: April 2008

p38 MAPK has been reported to regulate the inflammatory response in various cell types via extracellular stimuli. p38 MAPK activation also results in the induction of heme oxygenase (HO)-1, which exerts potent anti-inflammatory effects. Although studies have shown that 17β-estradiol (E2) prevented organ dysfunction following trauma-hemorrhage, it remains unknown whether p38 MAPK/HO-1 plays any role in E2-mediated attenuation of intestinal injury under those conditions. To study this, male rats underwent trauma-hemorrhage (mean blood pressure ∼40 mmHg for 90 min) followed by fluid resuscitation. At the onset of resuscitation, rats were treated with vehicle, E2(1 mg/kg body wt), the p38 MAPK inhibitor SB-203580 (2 mg/kg body wt) or E2plus SB-203580. Two hours thereafter, intestinal myeloperoxidase (MPO) activity and lactate, TNF-α, IL-6, ICAM-1, cytokine-induced neutrophil chemoattractant (CINC)-1, and macrophage inflammatory protein (MIP)-2 levels were measured. Intestinal p38 MAPK and HO-1 protein levels were also determined. Trauma-hemorrhage led to an increase in intestinal MPO activity and lactate, TNF-α, IL-6, ICAM-1, CINC-1, and MIP-2 levels. This was accompanied with a decrease in intestinal p38 MAPK activity and increase in HO-1 expression. Administration of E2normalized all the above parameters except HO-1, which was further increased following trauma-hemorrhage. Administration of SB-203580 with E2abolished the E2-mediated restoration of the above parameters as well as the increase in intestinal HO-1 expression following trauma-hemorrhage. These results suggest that the p38 MAPK/HO-1 pathway plays a critical role in mediating the salutary effects of E2on shock-induced intestinal injury.
Src regulates cell cycle protein expression and renal epithelial cell proliferation via PI3K/Akt signaling-dependent and -independent mechanisms
Authors: Xing Jingping , Zhang Zhu , Mao Haiping , Schnellmann Rick G. , Zhuang Shougang
Published: April 2008

Our recent studies showed that Src family kinases (SFKs) are important mediators of proliferation in renal proximal tubular cells (RPTC). In this study, we elucidate the signaling mechanisms that mediate SFK regulation of cell proliferation and cycle protein expression, and identify the SFK member responsible for these responses in a mouse RPTC line. Akt, a target of phosphoinositide-3-kinase (PI3K), and ERK1/2 were constitutively phosphorylated in RPTC cultured in the presence of serum. While treatment of cells with PP1, a specific SFK inhibitor, completely blocked phosphorylation of ERK1/2 and Akt, only inhibition of PI3K/Akt resulted in decreased RPTC proliferation. Incubation of cells with PP1 decreased cyclin D1 expression, decreased p27 and p57 phosphorylation, and increased p27 and p57 expression, two cyclin-dependent kinase inhibitors. Inhibition of the PI3K pathway decreased expression of cyclin D1 without altering expression of p27 and p57. In contrast, PP1 and PI3K inhibition had no effect on cyclin E and p21. Although RPTC expressed Src, Fyn, and Lyn, only siRNA-mediated knockdown of Src decreased RPTC proliferation, decreased cyclin D1 expression, and increased p27 and p57 expression. These data reveal that Src is a crucial mediator of RPTC proliferation and Src-mediated proliferation is associated with PI3K-dependent upregulation of cyclin D1 and PI3K-independent downregulation of p27 and p57.
Variability in Velocity Profiles During Free-Air Whisking Behavior of Unrestrained Rats
Authors: Towal R. Blythe , Hartmann Mitra J. Z.
Published: April 2008

During exploratory behaviors, the velocity of an organism's sensory surfaces can have a pronounced effect on the incoming flow of sensory information. In this study, we quantified variability in the velocity profiles of rat whisking during natural exploratory behavior that included head rotations. A wide continuum of profiles was observed, including monotonic, delayed, and reversing velocities during protractions and retractions. Three alternative hypotheses for the function of the variable velocity profiles were tested: 1) that they produce bilateral asymmetry specifically correlated with rotational head velocity, 2) that they serve to generate bilaterally asymmetric and/or asynchronous whisker movements independent of head velocity, and 3) that the different profiles—despite increasing variability in instantaneous velocity—reduce variability in the average whisking velocity. Our results favor the third hypothesis and do not support the first two. Specifically, the velocity variability within a whisk can be observed as a shift in the phase of the maximum velocity. We discuss the implications of these results for the control of whisker motion, horizontal object localization, and processing in the thalamus and cortex of the rat vibrissal system.
Mycoplasma genitalium Lipoproteins Induce Human Monocytic Cell Expression of Proinflammatory Cytokines and Apoptosis by Activating Nuclear Factor κB
Authors: Wu Yimou , Qiu Hong , Zeng Yanhua , You Xiaoxing , Deng Zhongliang , Yu Minjun , Zhu Cuiming
Published: April 2008

This study was designed to investigate the molecular mechanisms responsible for the induction of proinflammatory cytokines gene expression and apoptosis in human monocytic cell line THP‐1 stimulated by lipoproteins (LPs) prepared from Mycoplasma genitalium. Cultured cells were stimulated with M. genitalium LP to analyze the production of proinflammatory cytokines and expression of their mRNA by ELISA and RT‐PCR, respectively. Cell apoptosis was also detected by Annexin V‐FITC‐propidium iodide (PI) staining and acridine orange (AO)‐ethidium bromide (EB) staining. The DNA‐binding activity of nuclear factor‐κB (NF‐κB) was assessed by electrophoretic mobility shift assay (EMSA). Results showed that LP stimulated THP‐1 cells to produce tumor necrosis factor‐α (TNF‐α), interleukin‐1β (IL‐1β), and IL‐6 in a dose‐dependent manner. The mRNA levels were also upregulated in response to LP stimulation. LPs were also found to increase the DNA‐binding activity of NF‐κB, a possible mechanism for the induction of cytokine mRNA expression and the cell apoptosis. These effects were abrogated by PDTC, an inhibitor of NF‐κB. Our results indicate that M. genitalium‐derived LP may be an important etiological factor of certain diseases due to the ability of LP to produce proinflammatory cytokines and induction of apoptosis, which is probably mediated through the activation of NF‐κB.
Farthest Points and Subdifferential in p‐Normed Spaces
Authors: Hejazian S. , Niknam A. , Shadkam S.
Published: April 2008

We study the farthest point mapping in a p‐normed space X in virtue of subdifferential
of r(x) = sup{∥x−z∥p : z ∈ M}, where M is a weakly sequentially compact
subset of X. We show that the set of all points in X which have farthest point in M contains
a dense Gδ subset of X.
Routing in Vehicular Networks: Feasibility, Modeling, and Security
Authors: Broustis Ioannis , Faloutsos Michalis
Published: April 2008

Vehicular networks are sets of surface transportation systems that have the ability to communicate with each other. There are several possible network architectures to organize their in-vehicle computing systems. Potential schemes may include vehicle-to-vehicle ad hoc networks, wired backbone with wireless last hops, or hybrid architectures using vehicle-to-vehicle communications to augment roadside communication infrastructures. Some special properties of
these networks, such as high mobility, network partitioning, and constrained topology, differentiate them from other types of wireless networks. We provide an in-depth discussion on the important studies related to architectural design and routing for such networks. Moreover, we discuss the major security concerns appearing in vehicular networks.
FFT Analysis of a Series Loaded Resonant Converter-Based Power Supply for Pulsed Power Applications
Authors: Jadeja R. B. , Kanitkar S. A. , Shyam Anurag
Published: April 2008

An impulse power supply has been designed, simulated, and tested in order to feed the primary of a high-frequency transformer. Pulse power system has been widely used for plasma applications. The operational principle of the pulse power system is that the energy from the input source is stored in the capacitor bank device through a dc-dc converter. Then, when a discharging signal is given, the stored energy is released to the load. The new family of ZCS converters is suitable for high-power applications using insulated gate bipolar transistors (IGBTs). The power converter can achieve zero switching with the aid of high-frequency transformer. The device is capable of charging a 0.1 μF capacitor up to 5 kV which accounts for a charging power of 5 kJ/s. The novel control algorithm is achieved which eminently considers the nonlinear control characteristics of impulse power supply. The required charging voltage, together with the constraint on the charging time, translates into a required maximum power of 10 kW reduced in this initial version to 5 kW. The difficulty to reliably control such a power at the high-voltage side practically forbids any approach featuring a more or less stabilized DC high-voltage to be generated from a conventional 50 Hz transformer through rectification.
Inflammatory Breast Diseases during Lactation: Health Effects on the Newborn—A Literature Review
Authors: Wöckel Achim , Abou-Dakn Michael , Beggel Anna , Arck Petra
Published: April 2008

Breastfeeding‐associated inflammatory breast diseases appear especially during the first twelve weeks postpartum and are the most common reason for early cessation of breastfeeding. It also becomes increasingly evident that these inflammatory mammary diseases are triggered or perpetuated in a large part by psychosocial stress. Immunological processes taking place during this cascade in the mammary gland and consequences for the breastfeed newborn are mostly yet unknown. This review summarizes insights from studies on modulation of cytokine levels in breast milk during inflammatory processes like milk stasis and mastitis systematically. It also gives an overview on possible pathological effects, which these cytokine changes in the breast milk might have on the newborn.
TiO2 Films for Self‐Detection and Decontamination
Authors: Skubal Laura R. , McArthur Alan L. , Newville Matthew
Published: April 2008

Methods that rapidly detect, characterize, quantify, and decontaminate surfaces are essential following chemical or biological incidents. Our work focused on developing a “smart” surface, one that monitors itself and the overlying atmosphere and triggers a decontamination step when surface contamination is detected. Titanium dioxide was used to coat a ceramic surface containing skeletal impregnated platinum electrodes. The electrical resistance of the surface became altered by the introduction of a contaminant into the overlying atmosphere and its chemisorption to the surface. This change in resistance in turn initiated illumination by an external ultraviolet lamp to induce photocatalytic oxidation of the sorbed contaminant. Film resistance was concentration‐dependent, allowing self‐decontamination to be triggered at set pollutant levels. Preliminary results suggest that advanced surfaces and films can be developed to identify contaminant type and concentration and to initiate photocatalytic decontamination to meet regulatory or safety standards.
Genomics of Sorghum
Authors: Paterson Andrew H.
Published: April 2008

Sorghum (Sorghum bicolor (L.) Moench) is a subject of plant genomics research based on its importance as one of the world's leading cereal crops, a biofuels crop of high and growing importance, a progenitor of one of the world's most noxious weeds, and a botanical model for many tropical grasses with complex genomes. A rich history of genome analysis, culminating in the recent complete sequencing of the genome of a leading inbred, provides a foundation for invigorating progress toward relating sorghum genes to their functions. Further characterization of the genomes other than Saccharinae cereals may shed light on mechanisms, levels, and patterns of evolution of genome size and structure, laying the foundation for further study of sugarcane and other economically important members of the group.
Robust Stability and Stability Radius for Variational Control Systems
Authors: Sasu Bogdan
Published: April 2008

We consider an integral variational control system on a Banach space X and we study the connections between its uniform exponential stability and the (I(ℝ+, X), O(ℝ+, X)) stability, where I and O are Banach function spaces. We identify the viable classes of input spaces and output spaces related to the exponential stability of systems and provide optimization techniques with respect to the input space. We analyze the robustness of exponential stability in the presence of structured perturbations. We deduce general estimations for the lower bound of the stability radius of a variational control system in terms of input‐output operators acting on translation‐invariant spaces. We apply the main results at the study of the exponential stability of nonautonomous systems and analyze in the nonautonomous case the robustness of this asymptotic property.
A Gameplay Definition through Videogame Classification
Authors: Djaouti Damien , Alvarez Julian , Jessel Jean-Pierre , Methel Gilles , Molinier Pierre
Published: April 2008

This paper is part of an experimental approach aimed to
raise a videogames classification. Being inspired by the methodology that Propp used
for the classification of Russian fairy tales, we have identified recurrent diagrams within rules
of videogames, that we called “Gameplay Bricks”. The combinations of
these different bricks should allow us to represent a classification of all videogames in
accordance with their rules. In this article, we will study the nature of these bricks, especially the link they seem to have with two types of game rules: the rules that allow the player to “manipulate” the elements of the game, and the rules defining the “goal” of the game. This study will lead to an hypothesis about the nature of gameplay.
Numerical Analysis of Flow Field in Generator End‐Winding Region
Authors: Tong Wei
Published: April 2008

Cooling in an end‐winding region of a high‐powered, large‐sized generator still remains a challenge today because of a number of factors: a larger number of parts/components with irregular geometries, complexity in cooling flow paths, flow splitting and mixing, and interactions between rotor‐induced rotating flows and nonrotating flows from stationary sections. One of the key challenges is to model cooling flows passing through armature bars, which are made up of bundles of strands of insulated copper wires and are bent oppositely to cross each other.
This work succeeded in modeling a complex generator end‐winding region with great efforts to simplify the model by treating the armature bar region as a porous medium. The flow and pressure fields at the end‐winding region were investigated numerically using an axial symmetric computational fluid dynamics (CFD) model. Based on the analysis, the cooling flow rate at each flow branch (rotor‐stator gap, rotor subslot, outside space block, and small ventilation holes to the heat exchanger) was determined, and the high‐pressure gradient zones were identified. The CFD results have been successfully used to optimize the flow path configuration for improving the generator operation performance, and the control of the cooling flow, as well as minimizing windage losses and flow‐introduced noises.
Sliding Mode Control of Uncertain Neutral Stochastic Systems with Multiple Delays
Authors: Chen Dilan , Zhang Weidong
Published: April 2008

This paper is concerned with the sliding mode control for uncertain
stochastic neutral systems with multiple delays. A switching surface is
adopted first. Then, by means of linear matrix inequalities (LMIs), a sufficient
condition is derived to ensure the global stochastic stability of the
stochastic system in the sliding mode for all admissible uncertainties. The synthesized
sliding mode controller guarantees the existence of the sliding mode.
Comparison between Galileo CBOC Candidates and BOC(1,1) in Terms of Detection Performance
Authors: Dovis Fabio , Lo Presti Letizia , Fantino Maurizio , Mulassano Paolo , Godet Jérémie
Published: April 2008

Many scientific activities within the navigation field have been focused on the analysis of innovative modulations for both GPS L1C and Galileo E1 OS, after the 2004 agreement between United States and European Commission on the development of GPS and Galileo. The joint effort by scientists of both parties has been focused on the multiplexed binary offset carrier (MBOC) which is defined on the basis of its spectrum, and in this sense different time waveforms can be selected as possible modulation candidates. The goal of this paper is to present the detection performance of the composite BOC implementation of an MBOC signal in terms of detection and false alarm probabilities. A comparison among the CBOC and BOC(1,1) modulations is also presented to show how the CBOC solution, designed to have excellent tracking performance and multipath rejection capabilities, does not limit the acquisition process.
Investing in Lead-Time Variability Reduction in a Quality-Adjusted Inventory Model with Finite-Range Stochastic Lead-Time
Authors: Nasri Farrokh , Paknejad Javad , Affisco John
Published: April 2008

We study the impact of the efforts aimed at reducing the lead-time variability in a quality-adjusted stochastic inventory model. We assume that each lot contains a random number of defective units. More specifically, a logarithmic investment function is used that allows investment to be made to reduce lead-time variability. Explicit results for the optimal values of decision variables as well as optimal value of the variance of lead-time are obtained. A series of numerical exercises is presented to demonstrate the use of the models developed in this paper. Initially the lead-time variance reduction model (LTVR) is compared to the quality-adjusted model (QA) for different values of initial lead-time over uniformly distributed lead-time intervals from one to seven weeks. In all cases where investment is warranted, investment in lead-time reduction results in reduced lot sizes, variances, and total inventory costs. Further, both the reduction in lot-size and lead-time variance increase as the lead-time interval increases. Similar results are obtained when lead-time follows a truncated normal distribution. The impact of proportion of defective items was also examined for the uniform case resulting in the finding that the total inventory related costs of investing in lead-time variance reduction decrease significantly as the proportion defective decreases. Finally, the results of sensitivity analysis relating to proportion defective, interest rate, and setup cost show the lead-time variance reduction model to be quite robust and representative of practice.
International Standard Problems and Small Break Loss-of-Coolant Accident (SBLOCA)
Authors: Aksan N.
Published: April 2008

Best-estimate thermal-hydraulic system codes are widely used to perform safety and licensing analyses of nuclear power plants and also used in the design of advance reactors. Evaluation of the capabilities and the performance of these codes can be accomplished by comparing the code predictions with measured experimental data obtained on different test facilities. OECD/NEA Committee on the Safety of Nuclear Installations (CSNI) has promoted, over the last twenty-nine years, some forty-eight international standard problems (ISPs). These ISPs were performed in different fields as in-vessel thermal-hydraulic behaviour, fuel behaviour under accident conditions, fission product release and transport, core/concrete interactions, hydrogen distribution and mixing, containment thermal-hydraulic behaviour. 80% of these ISPs were related to the working domain of principal working group no.2 on coolant system behaviour (PWG2) and were one of the major PWG2 activities for many years. A global review and synthesis on the contribution that ISPs have made to address nuclear reactor safety issues was initiated by CSNI-PWG2 and an overview on the subject of small break LOCA ISPs is given in this paper based on a report prepared by a writing group. In addition, the relevance of small break LOCA in a PWR with relation to nuclear reactor safety and the reorientation of the reactor safety program after TMI-2 accident are shortly summarized. The experiments in four integral test facilities, LOBI, SPES, BETHSY, ROSA IV/LSTF and the recorded data during a steam generator tube rupture transient in the DOEL-2 PWR (Belgium) were the basis of the five small break LOCA related ISP exercises, which deal with the phenomenon typical of small break LOCAs in Western design PWRs. Some lessons learned from these small break LOCA ISPs are identified in relation to code deficiencies and capabilities, progress in the code capabilities, possibility of scaling, and various additional aspects. ISPs are providing unique material and benefits for some safety-related issues.
Influence of RollingTemperature on the PerfectionDegree of RecrystallizationCube Texture in Nickel
Authors: Sokolov B. K. , Gervasyeva I. V. , Rodionov D. P. , Khlebnikova Yu. V. , Stepanova I. N. , Dolgih D. V.
Published: April 2008

The effect of the rolling temperature on the deformation texture and the perfection
degree of a cube texture in pure‐nickel thin tape were investigated. The kinetics of
primary recrystallization was studied on samples that had undergone rolling at different
temperatures and the temperature of the onset of secondary recrystallization was
determined. Regularities of the structure formation in the samples are discussed. It is
established that the cube texture with the maximum sharpness is produced in the samples
rolled at room temperature.
Equatorial Convectively Coupled Waves in a Simple Multicloud Model
Authors: Khouider Boualem , Majda Andrew J.
Published: April 2008

Linear stability results for the multicloud model recently developed by the authors on an equatorial beta plane are presented here. The linearized equations, about a realistic radiative–convective equilibrium (RCE) are projected in the meridional direction via a Galerkin truncation procedure based on the parabolic cylinder functions. In a suitable parameter regime, the multicloud model exhibits convectively coupled Kelvin, M = 0 eastward (Yanai), and M = 1 westward inertia–gravity waves, unstable at the synoptic scales in agreement with the outgoing longwave radiation (OLR) spectral peaks observed by Wheeler and Kiladis. The horizontal wave structure and vertical wavenumber of the unstable waves qualitatively match those of the rotating equatorial shallow water waves but with a reduced phase speed, as in the observations. More importantly, they exhibit the same self-similar front-to-rear vertical tilt in the zonal winds, temperature, and heating fields as observed by Kiladis and colleagues. Similar to the case without rotation (from earlier work) a wave life cycle is identified, once again demonstrating the crucial role, played by congestus clouds and moisture, of preconditioning and moistening prior to deep convection and of triggering and maintaining the instability. When the troposphere is excessively dry, the convective wave instability fades out and an instability of low-frequency modes moving in both eastward and westward directions takes place. The eigenstructure of the low-frequency modes projects heavily on the congestus and moisture components and exhibits a quadruple vortex configuration reminiscent of Rossby waves with strong meridional convergence of warm and moist air toward the equatorial belt, suggesting a moistening and preconditioning role resembling the congestus standing mode seen in the case without rotation.
Structural and Intensity Changes of Hurricane Bret (1999). Part I: Environmental Influences
Authors: Lowag Alexander , Black Michael L. , Eastin Matthew D.
Published: April 2008

Hurricane Bret underwent a rapid intensification (RI) and subsequent weakening between 1200 UTC 21 August and 1200 UTC 22 August 1999 before it made landfall on the Texas coast 12 h later. Its minimum sea level pressure fell 35 hPa from 979 to 944 hPa within 24 h. During this period, aircraft of the National Oceanic and Atmospheric Administration (NOAA) flew several research missions that sampled the environment and inner core of the storm. These datasets are combined with gridded data from the National Centers for Environmental Prediction (NCEP) Global Model and the NCEP–National Center for Atmospheric Research (NCAR) reanalyses to document Bret’s atmospheric and oceanic environment as well as their relation to the observed structural and intensity changes. Bret’s RI was linked to movement over a warm ocean eddy and high sea surface temperatures (SSTs) in the Gulf of Mexico coupled with a concurrent decrease in vertical wind shear. SSTs at the beginning of the storm’s RI were approximately 29°C and steadily increased to 30°C as it moved to the north. The vertical wind shear relaxed to less than 10 kt during this time. Mean values of oceanic heat content (OHC) beneath the storm were about 20% higher at the beginning of the RI period than 6 h prior. The subsequent weakening was linked to the cooling of near-coastal shelf waters (to between 25° and 26°C) by prestorm mixing combined with an increase in vertical wind shear. The available observations suggest no intrusion of dry air into the circulation core contributed to the intensity evolution. Sensitivity studies with the Statistical Hurricane Intensity Prediction Scheme (SHIPS) model were conducted to quantitatively describe the influence of environmental conditions on the intensity forecast. Four different cases with modified vertical wind shear and/or SSTs were studied. Differences between the four cases were relatively small because of the model design, but the greatest intensity changes resulted for much cooler prescribed SSTs. The results of this study underscore the importance of OHC and vertical wind shear as significant factors during RIs; however, internal dynamical processes appear to play a more critical role when a favorable environment is present.
Teacher Learning: the Key to Educational Reform
Authors: Lieberman Ann , Pointer Mace Désirée H.
Published: April 2008

This letter to the next president of the United States recommends the transformation of teacher in-service learning as a powerful means of education reform. Too often, professional development is perceived by teachers as being idiosyncratic and irrelevant. The authors recommend a reconceptualization of professional learning for practicing teachers, in which educators are involved in learning communities, these communities evolve over time, and they revolve around norms of openness, scholarly rigor, and collaborative construction of professional knowledge. The authors describe three such environments of professional learning—the National Writing Project, the Carnegie Academy for the Scholarship of Teaching and Learning, and the Quest Project for Signature Pedagogies in Teacher Education—and recommend that the incoming chief executive should capitalize on the strengths of such programs and extend them to many more teachers nationwide.