bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling of Thermal Stresses and Thermal Cracking During Heating of Large Ingots
Authors: Alam M. K. , Goetz R. L. , Semiatin S. L.
Published: February 2008

The development of temperature gradients and thermal stresses during the heating of large ingots has been investigated with special reference to the selection of heating schedules for brittle intermetallic materials such as titanium aluminides. A 1-D analytical (series) solution for radial temperature transients was used in conjunction with an elasticity analysis to determine the maximum thermal stresses that would be generated during ingot heating. The temperature gradients and stresses were seen to be strongly dependent on Fourier and Biot Numbers. In addition, finite element method simulations incorporating end effects and variations of thermal and elastic properties with temperature were performed and compared to the analytical results. Comparison of the predicated thermal stresses and actual ingot heating observations suggest that cracking is controlled by a maximum normal stress criterion.
Assessment of Tool Wear in Milling Using Acoustic Emission Detected by a Fiber-Optic Interferometer
Authors: Carolan T. A. , Hand D. P. , Barton J. S. , Jones J. D. C. , Wilkinson P. , Reuben R. L.
Published: February 2008

Acoustic emission (AE) has previously been shown to be a useful technique in monitoring the state of wear of cutting tools. The piezo-electric transducers conventionally used for AE detection are contacting devices with a limited bandwidth. This paper describes the use of a robust fiber optic interferometer for the in-process measurement of AE during the face milling of annealed En24 steel to provide tool wear information via analysis of the rms AE signal. The interferometer displayed an improved diagnostic capability over a conventional piezoelectric sensor due to its advantages of being non-contacting, broadband with a flat frequency response to displacement, and providing absolute calibration.
Dual-Sensor Based Robotic Deburring
Authors: Bone G. M. , Elbestawi M. A.
Published: February 2008

New results quantifying the performance of a vision and force sensor based robotic deburring system at high feedrates and on stainless steel parts are presented. The performance with stainless steel is similar to that achieved with mild steel due to adaptation of the process model. Increasing the feedrate from 25 mm/s to 50 mm/s did not greatly affect deburring performance and could be used to reduce cycle time. The dual-sensor approach is shown to be 14 times more reliable than a single sensor solution. The overall accuracy of the system is ±30 μm for straight edged parts, and ±60 μm for 2-d edged parts with geometry similar to those tested.
Accurate Robot Motion-Time Model of Start/Stop Point-to-Point Operations
Authors: Wang Ching-Cheng
Published: February 2008

An accurate robot motion-time (ARM-Time) model is explored to be used in predicting, with an unprecedented accuracy, the motion time of start/stop point-to-point operations. Unlike the existing motion-time models observing only the velocity feedback controller’s target profile, the ARM-Time model adequately characterizes the motion time function of position and velocity feedback robots. The ARM-Time model has been applied to predict motion times of the IBM 7547, IBM 7545 and PUMA 560 industrial robots. The comparison of predicted and measured motion times reveals a less than 1 percent prediction error for the IBM 7547 and IBM 7545 robots, and about 0.3 percent for the PUMA 560 robot.
A Digraphic Approach for Dimensional Chain Identification in Design and Manufacturing
Authors: Ji P. , Fuh J. Y. H. , Ahluwalia R. S.
Published: February 2008

In order to determine working dimensions and tolerances of a process plan, a tolerance chart is often employed. Dimensional chain identification is a necessary step in the tolerance charting procedures. This paper presents a digraphic representation for the tolerance chart. Two directed trees are generated from working dimensions, blueprint dimensions and stock removals of the tolerance chart. These trees are then used to identify dimensional chains in order to find the relationships among the design and manufacturing dimensions. Furthermore, the concept of a reverse dimensional chain is introduced. The reverse dimensional chains can also be identified from the directed trees. The relationship between the forward and reverse dimensional chains is also discussed. Finally, the applications of dimensional chains to the determination of the working dimensions and tolerances are briefly described.
An Evaluation of Chip Separation Criteria for the FEM Simulation of Machining
Authors: Huang J. M. , Black J. T.
Published: February 2008

Different chip separation criteria for the FEM simulation of machining were examined. Criterion based on distance between the tool tip and the node located immediately ahead, criterion based on maximum shear stress in the element ahead of the tool tip, criterion based on average maximum shear stress in the shear plane, and criterion based on a combination of distance and stress were investigated. Under conditions of smooth separation of chip from workpiece, simulation results showed that, during steady-state cutting, the type of chip separation criteria did not greatly affect chip geometry, nor distributions of stress and strain. The magnitude of the chip separation criteria also did not significantly affect chip geometry and distributions of stress in the chip but it did affect the chip separation process, distributions of stress in the machined surface, and distributions of effective plastic strain both in the chip and in the machined surface. During the initiation of cutting, neither the geometrical nor physical criteria simulate the machining process correctly. A combination of geometric and physical criteria was also recommended in this study.
Central Bursting and Optimal Die Profile for Axisymmetric Extrusion
Authors: Venkata Reddy N. , Dixit P. M. , Lal G. K.
Published: February 2008

A simple criterion for predicting the initiation of central burst in extrusion is proposed. The geometric conditions to avoid central bursting are predicted by using the proposed criterion under various process conditions and material properties. The optimal die profiles which minimize the extrusion power are also obtained for various process conditions. The mixed (pressure-velocity) formulation is used along with the Householder method to solve the resulting equations. It is shown that the optimal die profiles satisfy the conditions for prevention of central burst. The predictions based on the proposed criterion are in good agreement with the experimental observations and are in conformity with the results published earlier.
BOLD Responses Reflecting Dopaminergic Signals in the Human Ventral Tegmental Area
Authors: D'Ardenne Kimberlee , McClure Samuel M. , Nystrom Leigh E. , Cohen Jonathan D.
Published: February 2008

Current theories hypothesize that dopamine neuronal firing encodes reward prediction errors. Although studies in nonhuman species provide direct support for this theory, functional magnetic resonance imaging (fMRI) studies in humans have focused on brain areas targeted by dopamine neurons [ventral striatum (VStr)] rather than on brainstem dopaminergic nuclei [ventral tegmental area (VTA) and substantia nigra]. We used fMRI tailored to directly image the brainstem. When primary rewards were used in an experiment, the VTA blood oxygen level–dependent (BOLD) response reflected a positive reward prediction error, whereas the VStr encoded positive and negative reward prediction errors. When monetary gains and losses were used, VTA BOLD responses reflected positive reward prediction errors modulated by the probability of winning. We detected no significant VTA BOLD response to nonrewarding events.
Quantum Critical Electron Systems: The Uncharted Sign Worlds
Authors: Zaanen J.
Published: February 2008

Phases of classical matter, such as solids and liquids, are ruled by emergence principles that are well understood. Although the same principles govern forms of quantum matter that have no secrets for physicists, such as the superfluids, having to deal with fermions and the associated Fermi sign problem shatters this analogy. This Perspective addresses the Fermion sign problem and describes experiments on metals undergoing quantum phase transitions exhibiting scale-invariant electronic behavior, a description of which is at odds with established quantum theory.
Detection of
Histoplasma capsulatum
Antigenuria by Ultrafiltration of Samples with False-Negative Results
Authors: Egan Lindsey , Connolly Patricia A. , Fuller Deanna , Davis Thomas E. , Witt John , Knox Kenneth S. , Hage Chadi A. , Wheat L. Joseph
Published: February 2008

Patients with histoplasmosis may test falsely negative for
Histoplasma capsulatum
antigenuria. In some cases antigen is present at levels below the assay's detection limit, and ultrafiltration could improve sensitivity. Antigen was detected following ultrafiltration in 73.8% of falsely negative specimens versus 2% of controls. Ultrafiltration improved sensitivity with a small reduction in specificity.
Lagos Bat Virus in Kenya
Authors: Kuzmin Ivan V. , Niezgoda Michael , Franka Richard , Agwanda Bernard , Markotter Wanda , Beagley Janet C. , Urazova Olga Y. , Breiman Robert F. , Rupprecht Charles E.
Published: February 2008

During lyssavirus surveillance, 1,221 bats of at least 30 species were collected from 25 locations in Kenya. One isolate of
Lagos bat virus
(LBV) was obtained from a dead
Eidolon helvum
fruit bat. The virus was most similar phylogenetically to LBV isolates from Senegal (1985) and from France (imported from Togo or Egypt; 1999), sharing with these viruses 100% nucleoprotein identity and 99.8 to 100% glycoprotein identity. This genome conservancy across space and time suggests that LBV is well adapted to its natural host species and that populations of reservoir hosts in eastern and western Africa have sufficient interactions to share pathogens. High virus concentrations, in addition to being detected in the brain, were detected in the salivary glands and tongue and in an oral swab, suggesting that LBV is transmitted in the saliva. In other extraneural organs, the virus was generally associated with innervations and ganglia. The presence of infectious virus in the reproductive tract and in a vaginal swab implies an alternative opportunity for transmission. The isolate was pathogenic for laboratory mice by the intracerebral and intramuscular routes. Serologic screening demonstrated the presence of LBV-neutralizing antibodies in
E. helvum
and
Rousettus aegyptiacus
fruit bats. In different colonies the seroprevalence ranged from 40 to 67% and 29 to 46% for
E. helvum
and
R. aegyptiacus
, respectively. Nested reverse transcription-PCR did not reveal the presence of viral RNA in oral swabs of bats in the absence of brain infection. Several large bat roosts were identified in areas of dense human populations, raising public health concerns for the potential of lyssavirus infection.
Infectious Spleen and Kidney Necrosis Virus ORF48R Functions as a New Viral Vascular Endothelial Growth Factor
Authors: Wang Zi-Liang , Xu Xiao-Peng , He Bai-Liang , Weng Shao-Ping , Xiao Jia , Wang Li , Lin Ting , Liu Xi , Wang Qing , Yu Xiao-Qiang , He Jian-Guo
Published: February 2008

Infectious spleen and kidney necrosis virus
(ISKNV) causes a pandemic and serious disease in fish. Infection by ISKNV causes epidermal lesions, in which petechial hemorrhages and abdominal edema are prominent features. ISKNV ORF48R contains a domain similar to that of the platelet-derived growth factor and vascular endothelial growth factor (VEGF) families of proteins. ISKNV ORF48R showed higher similarity to the VEGFs encoded by
Megalocytivirus
and
Parapoxvirus
than to those encoded in fish and mammals. We used zebrafish as a model and constructed a recombinant plasmid containing the DNA sequence of ISKNV ORF48R to study ISKNV infection. The plasmid was microinjected into zebrafish embryos at the one-cell stage. Overexpression of the ISKNV ORF48R gene results in pericardial edema and dilation at the tail region of zebrafish embryos, suggesting that ISKNV ORF48R induces vascular permeability. ISKNV ORF48R is also able to stimulate a striking expression of
flk1
in the zebrafish dorsal aorta and the axial vein. Furthermore, ISKNV ORF48R, while cooperating with zebrafish VEGF
121
, can stimulate more striking expression of
flk1
than can either ISKNV ORF48R or zebrafish VEGF
121
alone. However, decreased expression of FLK-1 by gene knockdown results in the disappearance of pericardial edema and dilation at the tail region of zebrafish embryos induced by overexpression of ISKNV ORF48R in the early stages of embryonic development.
Identification of the oriI-Binding Site of Poliovirus 3C Protein by Nuclear Magnetic Resonance Spectroscopy
Authors: Amero C. D. , Arnold J. J. , Moustafa I. M. , Cameron C. E. , Foster M. P.
Published: February 2008

Replication of picornaviral genomes requires recognition of at least three
cis
-acting replication elements: oriL, oriI, and oriR. Although these elements lack an obvious consensus sequence or structure, they are all recognized by the virus-encoded 3C protein. We have studied the poliovirus 3C-oriI interaction in order to begin to decipher the code of RNA recognition by picornaviral 3C proteins. oriI is a stem-loop structure that serves as the template for uridylylation of the peptide primer VPg by the viral RNA-dependent RNA polymerase. In this report, we have used nuclear magnetic resonance (NMR) techniques to study 3C alone and in complex with two single-stranded RNA oligonucleotides derived from the oriI stem. The
1
H-
15
N spectra of 3C recorded in the presence of these RNAs revealed site-specific chemical shift perturbations. Residues that exhibit significant perturbations are primarily localized in the amino terminus and in a highly conserved loop between residues 81 and 89. In general, the RNA-binding site defined in this study is consistent with predictions based on biochemical and mutagenesis studies. Although some residues implicated in RNA binding by previous studies are perturbed in the 3C-RNA complex reported here, many are unique. These studies provide unique site-specific insight into residues of 3C that interact with RNA and set the stage for detailed structural investigation of the 3C-RNA complex by NMR. Interpretation of our results in the context of an intact oriI provides insight into the architecture of the picornavirus VPg uridylylation complex.
Hantavirus Causing Hemorrhagic Fever with Renal Syndrome Enters from the Apical Surface and Requires Decay-Accelerating Factor (DAF/CD55)
Authors: Krautkrämer Ellen , Zeier Martin
Published: February 2008

The Old World hantaviruses, members of the familyBunyaviridae, cause hemorrhagic fever with renal syndrome (HFRS). Transmission to humans occurs via inhalation of aerosols contaminated with the excreta of infected rodents. The viral antigen is detectable in dendritic cells, macrophages, lymphocytes, and, most importantly, microvascular endothelial cells. However, the site and detailed mechanism of entry of HFRS-causing hantaviruses in polarized epithelial cells have not yet been defined. Therefore, this study focused on the entry of the pathogenic hantaviruses Hantaan and Puumala into African green monkey kidney epithelial cells and primary human endothelial cells. The polarized epithelial and endothelial cells were found to be susceptible to hantavirus infection exclusively from the apical surface. Treatment with phosphatidylinositol-specific phospholipase C, which removes glycosylphosphatidylinositol (GPI)-anchored proteins from the cell surface, protects cells from infection, indicating that hantaviruses require a GPI-anchored protein as a cofactor for entry. Decay-accelerating factor (DAF)/CD55 is a GPI-anchored protein of the complement regulatory system and serves as a receptor for attachment to the apical cell surface for a number of viruses. Infection was reduced by the pretreatment of hantaviral particles with human recombinant DAF. Moreover, the treatment of permissive cells with DAF-specific antibody blocked infection. These results demonstrate that the Old World hantaviruses Hantaan and Puumala enter polarized target cells from the apical site and that DAF is a critical cofactor for infection.
Kaposi's Sarcoma-Associated Herpesvirus Latent Gene vFLIP Inhibits Viral Lytic Replication through NF-κB-Mediated Suppression of the AP-1 Pathway: a Novel Mechanism of Virus Control of Latency
Authors: Ye Feng-Chun , Zhou Fu-Chun , Xie Jian-Ping , Kang Tao , Greene Whitney , Kuhne Kurt , Lei Xiu-Fen , Li Qui-Hua , Gao Shou-Jiang
Published: February 2008

Kaposi's sarcoma-associated herpesvirus (KSHV) latency is central to the evasion of host immune surveillances and induction of KSHV-related malignancies. The mechanism of KSHV latency remains unclear. Here, we show that the KSHV latent gene vFLIP promotes viral latency by inhibiting viral lytic replication. vFLIP suppresses the AP-1 pathway, which is essential for KSHV lytic replication, by activating the NF-κB pathway. Thus, by manipulating two convergent cellular pathways, vFLIP regulates both cell survival and KSHV lytic replication to promote viral latency. These results also indicate that the effect of the NF-κB pathway on KSHV replication is determined by the status of the AP-1 pathway and hence provide a mechanistic explanation for the contradictory role of the NF-κB pathway in KSHV replication. Since the NF-κB pathway is commonly activated during infection of gammaherpesviruses, these findings might have general implications for the control of gammaherpesviral latency.
Enumeration and Functional Evaluation of Virus-Specific CD4
+
and CD8
+
T Cells in Lymphoid and Peripheral Sites of Coxsackievirus B3 Infection
Authors: Kemball Christopher C. , Harkins Stephanie , Whitton J. Lindsay
Published: February 2008

Previous studies have suggested that coxsackievirus B (CVB) activates CD8
+
T cells in vivo, but the extent of this activation and the antigen specificity of the CD8
+
T cells remain uncertain. Furthermore, CVB-induced CD4
+
T-cell responses have not been carefully investigated. Herein, we evaluate CD8
+
and CD4
+
T-cell responses both in a secondary lymphoid organ (spleen) and in peripheral tissues (heart and pancreas), using a recombinant CVB3 (rCVB3.6) that encodes well-characterized CD8
+
and CD4
+
T-cell epitopes. Despite reaching high levels in vivo, rCVB3.6 failed to trigger a marked expansion of CD8
+
or CD4
+
T cells, and T-cell activation was surprisingly limited. Furthermore, epitope-specific effector functions could not be detected using highly sensitive in vivo and ex vivo assays. Moreover, major histocompatibility complex (MHC) class I tetramer analysis indicated that our inability to detect CVB3-specific CD8
+
T-cell responses could not be explained by the cells being dysfunctional. In contrast to naïve T cells, epitope-specific memory CD8
+
and CD4
+
T cells proliferated markedly, indicating that both of the rCVB3.6-encoded epitopes were presented by their respective MHC molecules in vivo. These data are consistent with the observation that several CVB3 proteins can limit the presentation of viral epitopes on the surface of infected cells and suggest that the level of MHC/peptide complex is sufficient to trigger memory but not naïve T cells. Finally, our findings have implications for the biological significance of cross-priming, a process thought by some to be important for the induction of antiviral CD8
+
T-cell responses.
NP, PB1, and PB2 Viral Genes Contribute to Altered Replication of H5N1 Avian Influenza Viruses in Chickens
Authors: Wasilenko Jamie L. , Lee Chang Won , Sarmento Luciana , Spackman Erica , Kapczynski Darrell R. , Suarez David L. , Pantin-Jackwood Mary J.
Published: February 2008

The virulence determinants for highly pathogenic avian influenza viruses (AIVs) are considered multigenic, although the best characterized virulence factor is the hemagglutinin (HA) cleavage site. The capability of influenza viruses to reassort gene segments is one potential way for new viruses to emerge with different virulence characteristics. To evaluate the role of other gene segments in virulence, we used reverse genetics to generate two H5N1 recombinant viruses with differing pathogenicity in chickens. Single-gene reassortants were used to determine which viral genes contribute to the altered virulence. Exchange of the PB1, PB2, and NP genes impacted replication of the reassortant viruses while also affecting the expression of specific host genes. Disruption of the parental virus' functional polymerase complexes by exchanging PB1 or PB2 genes decreased viral replication in tissues and consequently the pathogenicity of the viruses. In contrast, exchanging the NP gene greatly increased viral replication and expanded tissue tropism, thus resulting in decreased mean death times. Infection with the NP reassortant virus also resulted in the upregulation of gamma interferon and inducible nitric oxide synthase gene expression. In addition to the impact of PB1, PB2, and NP on viral replication, the HA, NS, and M genes also contributed to the pathogenesis of the reassortant viruses. While the pathogenesis of AIVs in chickens is clearly dependent on the interaction of multiple gene products, we have shown that single-gene reassortment events are sufficient to alter the virulence of AIVs in chickens.
Sediments of ice-dammed, self-draining Ape Lake, British Columbia
Authors: Gilbert Robert , Desloges Joseph R.
Published: February 2008

The glacier damming Ape Lake has withdrawn from its Neoglacial terminal moraines in the lake since early in this century at an average rate of 15 m/a. As a result, the first known drainings of Ape Lake occurred in October 1984 and August 1986. In each event, about 54% of the volume of the lake was lost through a tunnel in the damming glacier. Most of the remaining water was held in the deep basin of the lake behind partially breached Neoglacial terminal moraines. As the glaciers have withdrawn, the character of the sediments has changed. Sediments in the deep basin of the lake are varved, but the grain size, especially of the summer deposits, has decreased and rates of sedimentation have decreased from about 4 mm/a to less than 2 mm/a. In shallow water, deposition of varved sediments has given way to the deposition of massive sediments at rates of less than 1 mm/a. Ice-rafted debris is rare in deep water, despite the presence of calving bergs.During and following the first draining, significant subaerial erosion occurred as a result of the event itself, the drawdown and steepened gradients, and the action of waves on the exposed sediments as the lake refilled. In proximal areas, distinct deposits within the normal winter deposits are recognised. In deep water, deposition of massive, highly underconsolidated, fine-grained sediments occurred. Organic debris released from shallow deposits by erosion has become concentrated in both shallow- and deep-water sediments. Within a year of the first draining, sediment loads in the lake water were returning to normal.
Subsurface in situ stress magnitudes from oil-well drilling records: an example from the Venture area, offshore eastern Canada
Authors: Ervine W. B. , Bell J. S.
Published: February 2008

This report describes a method of obtaining information on in situ stress magnitudes at depth in sedimentary basins by using information gathered while drilling oil wells. If we assume that one of the principal stresses is vertical at a well site, principal stress magnitudes can be estimated in the following manner. Sv is equated with overburden load, which is obtained by integrating density log records. SHmin is equated with leak-off test pressures measured over short open-hole intervals and also from selected initial feed-rate pressures. SHmax is derived from the equation SHmax = 2P1 − P0, where P1 is the leak-off pressure or the initial feed-rate pressure, and P0 is the fluid pressure over a specified depth interval. This relationship is a simplified approximation of Hubbert and Willis' well-known equation Pb = T + 3SHmin − SHmax − P0, describing hydraulic fracturing around a borehole.Using this approach, stress magnitudes were estimated for 44 depth intervals in four wells drilled over the Venture structure on the Scotian Shelf, offshore eastern Canada. The information obtained between subsea depths of 815 and 5783 m provides a consistent record and points to a stress regime where SHmax > Sv > SHmin. At approximately 6000 m, Sv and SHmin may become equal. Inferred stress magnitudes in the upper 3000 m are comparable to those measured in clastic rocks in western Canada.
Albedo model for shallow prairie snow covers
Authors: Gray D. M. , Landine P. G.
Published: February 2008

A model for simulating the decrease in albedo of melting prairie snow covers is presented. Its application for calculating net radiation and establishing the time of melt is demonstrated. It is expected the routine will find use in operational systems for synthesizing and forecasting streamflow runoff from snowmelt.The model is based on point and aerial observations of incoming and reflected global radiation taken from February 1 to the end of ablation of the seasonal snow cover, over a 14 year period, in the open grassland area of western Canada. For complete snow covers not subject to frequent melt events, the albedo-depletion curve is approximated by three line segments of constant slope describing the periods of (1) premelt—the months preceding the occurrence of "active" melt; (2) melt—the period of rapid ablation that leads to the disappearance of the seasonal snow cover, and (3) postmelt—the days following melt.An algorithm of the model is developed and procedures for defining the start of melt and albedo depletion from daily inputs of net radiation, maximum air temperature, and snow-cover and snowfall depths are described. Data are presented that demon strate close agreement between simulated and measured albedo-depletion curves for "deep" (depth > 25 cm) and "shallow" (depth ≤25 cm) snow covers. The mean difference between simulated and measured albedo on 74 days of melt over 7 years of record was calculated to be −0.0007 with a standard deviation of 0.17.The model is applied for calculating daily net radiation during the melt period. This analysis makes use of an empirical relationship to estimate net radiation from the clear-sky insolation, sunshine hours, and simulated albedo. Comparison of the differences between simulated and measured values for 62 days of melt gave a mean and standard deviation of 0.49 and 2.05 MJ/(m2∙d), respectively.
Late Ordovician sand-wave complexes on Anticosti Island, Quebec: a marine tidal embayment?
Authors: Long D. G. F. , Copper Paul
Published: February 2008

Laterally discontinuous, mixed carbonate–siliciclastic sandstones in the upper Vaureal and lower Ellis Bay formations of Anticosti Island were deposited on an equatorial carbonate ramp with a slope of less than 1°. The 10–18 m thick sandstones are interpreted as subaqueous sand-wave complexes analogous to detached parts of modern shoreface-connected sand ridges. These record storm-enhanced, tidal modification of a northerly derived shoal retreat massif that may have formed in response to recovery from global sea-level lowstands in the Late Ordovician (Ashgill: late Rawtheyan – Hirnantian). The sand-wave complexes formed within a tidal embayment that was confined by the Precambrian Shield to the north and northwest by rising tectonic highlands of the Humber Zone in Newfoundland to the east, and by active tectonic highlands in the Quebec Appalachians (Gaspésie) to the south. Paleocurrent distributions, parallel to the western margins of the Strait of Belle Isle, suggest that the north end of the embayment was closed in Late Ordovician time. Low-diversity faunas within the sand units consist mostly of sowerbyellid, strophomenid, and rhynchonellid brachiopods, bivalves, gastropods, large aulacerid stromatoporoids, and large, domed favositid corals. These "sandy fades" faunas belong to communities significantly different from those found in the laterally interfingering and overlying carbonates and shales, suggesting that the sand waves played an important role in local community modification.
Lithostratigraphie et dynamique glaciaires au Wisconsinien, île d'Anticosti, golfe du Saint-Laurent
Authors: St-Pierre Luc , Gwyn Q. H. J. , Dubois J. M. M.
Published: February 2008

The Laurentide Ice Sheet deposited three tills on Anticosti Island. The oldest, the Rivière à la Patate Till, was formed by southeastward-flowing ice as determined from till fabrics. The till has an estimated age of 85 000 years BP based on the aminoacid racemization of shell fragments in overlying marine sediments. Thus it is probably Early Wisconsinan in age. The Middle Wisconsinan Rivière Jupiter Till and the Late Wisconsinan Île d'Anticosti Till are the result of the southwest-flowing Laurentide ice. The ice flowed without restriction though without accomplishing deep erosion of the bedrock, as indicated by glaciotectonic structures and till fabrics. However, striated blocks and pebbles in the tills reveal that basal shearing occurred. The ice limit in the Gulf of St. Lawrence from about 36 000 years BP onwards was located along the south coast of the island. This was the result of active calving at the margin of the relatively slow moving ice sheet. During retreat of the ice sheet, an ice cap became isolated on the island. It appears to have remained active in the western part of the island, where it formed the Sainte-Marie Moraine on the south, west, and north coasts, but was less active in the eastern part of the island, where a loose, sandy, but rare till (the Sainte-Marie Till) is the only proof of its activity. Deeper water in the eastern end of the Jacques-Cartier Strait, north of the island, accelerated ice calving and thus probably reduced the ice dynamic in the eastern part of the island. The names of tills used here are proposed as formal nomenclature.
On the inorganic character of Halichondrites graphitiferus Matthew, a supposed sponge from the Precambrian of Saint John, New Brunswick
Authors: Miller Randall F.
Published: February 2008

Discovery of the holotype of Halichondrites graphitiferus Matthew in the collections of the New Brunswick Museum made it necessary to reexamine its affinity to the Porifera as first described by G. F. Matthew in 1890. Since its publication, the organic nature of H. graphitiferus has been questioned; however, the holotype has not been accessible until recent organization of the museum's collections. Examination of the holotype suggests the "spicules," described by Matthew from the Precambrian Green Head Group of Saint John, New Brunswick, are more likely a combination of scratches on the surface of the graphite and cleavage demonstrated by the mineral. Other "spicules" from Musquash Harbour, New Brunswick, are of a similar nature.
The Pontiac problem, Quebec–Ontario, in the light of gravity data
Authors: Kalliokoski J.
Published: February 2008

A belt of Archean quartzose metasedimentary gneisses with minor mafic volcanic rocks (the Pontiac Group) lies south of the Blake River and older Archean mafic volcanic rocks of the Abitibi Greenstone Belt, and is separated from them by the Larder Lake – Cadillac Break. To the west of the Pontiac Group, on strike, is the Archean Larder Lake Group of turbidite conglomerate, argillite, limestone, and iron formation with abundant mafic flows and intrusions. These strata also lie south of the Larder Lake – Cadillac Break and south of the Blake River and older Archean mafic volcanic rocks. The western contact between the Pontiac and Larder Lake groups is covered by a narrow north–south strip of Proterozoic Cobalt sedimentary rocks. On the basis of gravity work that compares the Bouguer gravity anomaly gradient across the Cadillac Break with that across the west margin of the Pontiac Group, it is proposed that the Larder Lake and Pontiac groups are separated by a north–south fault and that the Pontiac Group represents a lithologically distinct uplifted block. The Pontiac block may be an Archean terrane.
2.2 Ga age of zircons in three occurrences of Upper Proterozoic clastic rocks of the northern Cassiar terrane, Yukon and British Columbia
Authors: Erdmer P. , Baadsgaard H.
Published: February 2008

Analyses of detrital zircons from three occurrences of Upper Proterozoic clastic rocks of the northern Cassiar terrane in Yukon and northern British Columbia yield a U–Pb age of 2224 ± 22 Ma. The zircons apparently belong to a single population similar in age to zircons in stratigraphically equivalent rocks of the southern Cassiar terrane and to zircons in rocks in the Yukon–Tanana terrane of Alaska. A source terrane or area of the required age and extent has not yet been identified.
IDENTIFYING THE CONTRIBUTIONS OF UNIVERSAL EXTRA DIMENSIONS IN THE HIGGS SECTOR AT LINEAR e+e- COLLIDERS
Authors: DATTA ANINDYA , RAI SANTOSH KUMAR
Published: February 2008

We study the dilepton–dijet signal in the dominant Higgs production channel at a linear e+e- collider. We estimate the effects of universal extra dimension (UED) by a simple analysis of the cross-sections. The heavy Kaluza–Klein excitations of the Standard Model fields in UED can significantly alter the decay properties of the Higgs boson to loop-driven final states. We show that by taking a simple ratio between cross-sections of two different final states this difference can be very easily highlighted.
SHIFT CHARACTERISTICS OF Ni ION DISTRIBUTION IN Y-123 SUPERCONDUCTORS
Authors: LI PINGLIN , CHEN ZHENBANG , LI SHUNFANG , LU HEQIANG , ZHANG JIE , GAO LIMING
Published: February 2008

In Ni -doped YBCO systems, Ni ions have been generally thought to enter Cu (2) sites; in fact, the relevant arguments never ceased in the past decade, because various experimental results have not achieved a definite and consistent conclusion. The present paper systemically investigates YBa 2 Cu 3-x Ni x O 7-δ(x = 0~0.4) cuprates with X-ray diffraction, positron annihilation technique, and simulated calculations. The results show that Ni ions enter Cu (2) sites at the low-doped concentration, as the concentration increases, a certain proportion of Ni ions begin to enter the Cu (1) sites until the appearance of the impurity phase.
Process-centered review of object oriented software development methodologies
Authors: Ramsin Raman , Paige Richard F.
Published: February 2008

We provide a detailed review of existing object-oriented software development methodologies, focusing on their development processes. The review aims at laying bare their core philosophies, processes, and internal activities. This is done by using a process-centered template for summarizing the methodologies, highlighting the activities prescribed in the methodology while describing the modeling languages used (mainly diagrams and tables) as secondary to the activities. The descriptions produced using this template aim not to offer a critique on the methodologies and processes, but instead provide an abstract and structured description in a way that facilitates their elaborate analysis for the purposes of improving understanding, and making it easier to tailor, select, and evaluate the processes.
Rate-distortion optimized streaming of fine-grained scalable video sequences
Authors: Hefeeda Mohamed , Hsu Cheng-Hsin
Published: February 2008

We present optimal schemes for allocating bits of fine-grained scalable video sequences among multiple senders streaming to a single receiver. This allocation problem is critical in optimizing the perceived quality in peer-to-peer and distributed multi-server streaming environments. Senders in such environments are heterogeneous in their outgoing bandwidth and they hold different portions of the video stream. We first formulate and optimally solve the problem for individual frames, then we generalize to the multiple frame case. Specifically, we formulate the allocation problem as an optimization problem, which is nonlinear in general. We use rate-distortion models in the formulation to achieve the minimum distortion in the rendered video, constrained by the outgoing bandwidth of senders, availability of video data at senders, and incoming bandwidth of receiver. We show how the adopted rate-distortion models transform the nonlinear problem to an integer linear programming (ILP) problem. We then design a simple rounding scheme that transforms the ILP problem to a linear programming (LP) one, which can be solved efficiently using common optimization techniques such as the Simplex method. We prove that our rounding scheme always produces a feasible solution, and the solution is within a negligible margin from the optimal solution. We also propose a new algorithm (FGSAssign) for the single-frame allocation problem that runs in
O
(
n
log
n
) steps, where
n
is the number of senders. We prove that FGSAssign is optimal. Furthermore, we propose a heuristic algorithm (mFGSAssign) that produces near-optimal solutions for the multiple-frame case, and runs an order of magnitude faster than the optimal one. Because of its short running time, mFGSAssign can be used in real time. Our experimental study validates our analytical analysis and shows the effectiveness of our allocation algorithms in improving the video quality.
Video quality estimation in wireless IP networks
Authors: Babich Fulvio , D'orlando Marco , Vatta Francesca
Published: February 2008

This article proposes three methods to estimate the distortion deriving from packet losses in wireless video communication. The proposed methods take into account the short-term properties of the encoded video sequences. A suitable set of functions is adopted to model the distortion envelope resulting from multiple losses. The estimated performance is compared with the actual distortion, evaluated by decoding the received sequence with a properly designed decoder. Numerical results confirm the accuracy of the proposed models in approximating the actual Mean Square Error (MSE) for a wide range of loss rates. Some applications of the proposed algorithms are presented.
Optimization of interactive visual-similarity-based search
Authors: Nguyen Giang Phuong , Worring Marcel
Published: February 2008

At one end of the spectrum, research in interactive content-based retrieval concentrates on machine learning methods for effective use of relevance feedback. On the other end, the information visualization community focuses on effective methods for conveying information to the user. What is lacking is research considering the information visualization and interactive retrieval as truly integrated parts of one content-based search system. In such an integrated system, there are many degrees of freedom like the similarity function, the number of images to display, the image size, different visualization modes, and possible feedback modes. To base the optimal values for all of those on user studies is unfeasible. We therefore develop search scenarios in which tasks and user actions are simulated. From there, the proposed scheme is optimized based on objective constraints and evaluation criteria. In such a manner, the degrees of freedom are reduced and the remaining degrees can be evaluated in user studies. In this article, we present a system that integrates advanced similarity based visualization with active learning. We have performed extensive experimentation on interactive category search with different image collections. The results using the proposed simulation scheme show that indeed the use of advanced visualization and active learning pays off in all of these datasets.
Managing for innovation
Authors: Glass Robert L.
Published: February 2008

People versus process? Watts Humphrey says it's people
and
process.
Patterns, symmetry, and symmetry breaking
Authors: Zhao Liping
Published: February 2008

Explaining software patterns by breaking the symmetry created by programming languages.
Costs and benefits of XBRL adoption
Authors: Pinsker Robert , Li Shaomin
Published: February 2008

Financial reporting via XBRL is a low-cost method for increasing transparency and compliance while potentially decreasing a firm's cost of capital.
Niobe
Authors: Maccormick John , Thekkath Chandramohan A. , Jager Marcus , Roomp Kristof , Zhou Lidong , Peterson Ryan
Published: February 2008

The task of consistently and reliably replicating data is fundamental in distributed systems, and numerous existing protocols are able to achieve such replication efficiently. When called on to build a large-scale enterprise storage system with built-in replication, we were therefore surprised to discover that no existing protocols met our requirements. As a result, we designed and deployed a new replication protocol called
Niobe
. Niobe is in the primary-backup family of protocols, and shares many similarities with other protocols in this family. But we believe Niobe is significantly more
practical
for large-scale enterprise storage than previously published protocols. In particular, Niobe is simple, flexible, has rigorously proven yet simply stated consistency guarantees, and exhibits excellent performance. Niobe has been deployed as the backend for a commercial Internet service; its consistency properties have been proved formally from first principles, and further verified using the TLA + specification language. We describe the protocol itself, the system built to deploy it, and some of our experiences in doing so.
RIPPS
Authors: Mano Chad D. , Blaich Andrew , Liao Qi , Jiang Yingxin , Cieslak David A. , Salyers David C. , Striegel Aaron
Published: February 2008

Wireless network access has become an integral part of computing both at home and at the workplace. The convenience of wireless network access at work may be extremely beneficial to employees, but can be a burden to network security personnel. This burden is magnified by the threat of inexpensive wireless access points being installed in a network without the knowledge of network administrators. These devices, termed Rogue Wireless Access Points, may allow a malicious outsider to access valuable network resources, including confidential communication and other stored data. For this reason, wireless connectivity detection is an essential capability, but remains a difficult problem. We present a method of detecting wireless hosts using a local RTT metric and a novel packet payload slicing technique. The local RTT metric provides the means to identify physical transmission media while packet payload slicing conditions network traffic to enhance the accuracy of the detections. Most importantly, the packet payload slicing method is transparent to both clients and servers and does not require direct communication between the monitoring system and monitored hosts.
Verifying Completeness of Relational Query Answers from Online Servers
Authors: Pang Hweehwa , Tan Kian-Lee
Published: February 2008

The number of successful attacks on the Internet shows that it is very difficult to guarantee the security of online servers over extended periods of time. A breached server that is not detected in time may return incorrect query answers to users. In this article, we introduce authentication schemes for users to verify that their query answers from an online server are complete (i.e., no qualifying tuples are omitted) and authentic (i.e., all the result values are legitimate). We introduce a scheme that supports range selection, projection as well as primary key-foreign key join queries on relational databases. We also present authentication schemes for single- and multi-attribute range aggregate queries. The schemes complement access control mechanisms that rewrite queries dynamically, and are computationally secure. We have implemented the proposed schemes, and experiment results showed that they are practical and feasible schemes with low overheads.
A systems analysis of systems integration
Authors: Schaefer Robert
Published: February 2008

Most if not all complex issues stated as problems intended to result in new systems may be analyzed using
systems decomposition
and then constructed by
synthesis
. Systems decomposition starts with a complex problem that may or may not be obviously solvable and deconstructs that problem into smaller more tractable problems that
can
be solved. Construction by synthesis treats the smaller solutions as building blocks. The key practical advantage to synthesis is that it permits concurrency of construction. The subsystems may be developed and tested independently in isolation. Not until integration will subsystems need to be brought together. Decomposition and synthesis are the
ideal
in theory. In practice there can be any number of problems. Potentially the most fatal of flaws can occur during decomposition where errors in abstraction lead to over-idealization of subsystem independence. Over-idealization leads to under-specification, that what is presumed to be independent is not. Once errors in subsystem specification are made, independent development ensures that undetected dependencies will remain undetected. Subsystem dependencies are hidden time bombs, dormant until the subsystems are brought together for systems integration. In systems integration the latent dependencies interact and
explode
in a manner most combinatorial. The term often used to describe the excitation of dormant dependencies is "emergent behavior". Emergent behavior is but one factor that plagues the integration of large software intensive systems. There have been few published analyses or case studies dedicated to systems integration, in particular analyses deemed useful as "lessons learned" for others to follow. This paper takes a hesitant first step, not towards a "lessons learned" but towards the meta, an estimation of the boundaries of what it might take before one can provide a useful "lessons learned".
More expressive market models and the future of combinatorial auctions
Authors: Golovin Daniel
Published: February 2008

Research on auctions and other engineered markets is undergoing a renaissance, spurred by the growth of computing power and communication networks, and the new opportunities for social and economic interaction that they enable. Previous research has been applied to good effect, perhaps most famously by search engines to allocate advertising space in keyword auctions. Other case studies of combinatorial auctions being used in practice can be found in the book of Cramton et al. [Cramton et al. 2006]. Despite these success stories, there is much more to do. In this letter, I will give my opinion as to the ultimate determinants of how successful research on engineered markets can be, with implications for where the community can focus attention to maximize its impact. I will use [Golovin 2007] to illustrate initial progress in the direction I have in mind.
Introduction
Authors: Hemaspaandra Lane A.
Published: February 2008

Warmest thanks to Arnaud and Malika both for making available here their work with Clemens and especially for sharing their moving memories of Clemens, the extreme beauty of whose research will via the literature remain forever available to all.
A simple proof of the polylog counting ability of first-order logic
Authors: Durand Arnaud , Lautemann Clemens , More Malika
Published: February 2008

The counting ability of weak formalisms (e.g., determining the number of 1's in a string of length
N
) is of interest as a measure of their expressive power, and also resorts to complexity-theoretic motivations: the more we can count the closer we get to real computing power. The question was investigated in several papers in complexity theory and in weak arithmetic around 1985. In each case, the considered formalism (AC
0
-circuits, first-order logic, Δ
0
) was shown to be able to count up to a polylogarithmic number. An essential part of the proofs is the construction of a 1-1 mapping from a small subset of {0, ...,
N
- 1} into a small initial segment. In each case the expressibility of this mapping depends on some strong argument (group-theoretic device or prime number theorem) or intricate construction. We present a coding device based on a collision-free hashing technique, leading to a completely elementary proof.