bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamic multivariate mean residual life functions
Authors: Shaked Moshe , Shanthikumar J. George 
Published: April 2006

In this paper we introduce and study a dynamic notion of mean residual life (mrl) functions in the context of multivariate reliability theory. Basic properties of these functions are derived and their relationship to the multivariate conditional hazard rate functions is studied.A partial ordering, called the mrl ordering, of non-negative random vectors is introduced and its basic properties are presented. Its relationship to stochastic ordering and to other related orderings (such as hazard rate ordering) is pointed out. Using this ordering it is possible to introduce a weak notion of positive dependence of random lifetimes. Some properties of this positive dependence notion are given.Finally, using the mrl ordering, a dynamic notion of multivariate DMRL (decreasing mean residual life) is introduced and studied. The relationship of this multivariate DMRL notion to other notions of dynamic multivariate aging is highlighted in this paper.
L'intégrale du mouvement brownien
Authors: Lachal Aimé 
Published: April 2006

Let be the Brownian motion process starting at the origin, its primitive and Ut = (Xt+x + ty, Bt + y), , the associated bidimensional process starting from a point . In this paper we present an elementary procedure for re-deriving the formula of Lefebvre (1989) giving the Laplace–Fourier transform of the distribution of the couple (σ α, Uσa), as well as Lachal's (1991) formulae giving the explicit Laplace–Fourier transform of the law of the couple (σ ab, Uσab), where σ α and σ ab denote respectively the first hitting time of from the right and the first hitting time of the double-sided barrier by the process . This method, which unifies and considerably simplifies the proofs of these results, is in fact a ‘vectorial' extension of the classical technique of Darling and Siegert (1953). It rests on an essential observation (Lachal (1992)) of the Markovian character of the bidimensional process .Using the same procedure, we subsequently determine the Laplace–Fourier transform of the conjoint law of the quadruplet (σ α, Uσa, σb, Uσb).
On closed ring queueing networks
Authors: Bambos Nicholas 
Published: April 2006

In this paper we first study ring structured closed queueing networks with distinguishable jobs. Under assumptions of periodicity and ergodicity of the service times, essentially the most general, it is shown that the limits defining the average flows of the jobs exist almost surely, and methods for their estimation by simulation are given. However, it turns out that the values of the flows depend on the initial positions of the jobs, due to the emergence of distinct persistent blocking modes. The effect of these modes on the behavior of general networks with queueing loops is examined.For independent and identically distributed service times, conditions are specified for the network to asymptotically approach a steady state at large times.Finally, we study the special case of ring networks with indistinguishable items and stationary and ergodic service times. It is shown that as the number of jobs in the network increases towards infinity, the average circulation time converges to the maximum of the expectations of the service times.
Braess's paradox in a queueing network with state-dependent routing
Authors: Calvert Bruce , Solomon Wiremu , Ziedins Ilze 
Published: April 2006

We consider initially two parallel routes, each of two queues in tandem, with arriving customers choosing the route giving them the shortest expected time in the system, given the queue lengths at the customer's time of arrival. All interarrival and service times are exponential.We then augment this network to obtain a Wheatstone bridge, in which customers may cross from one route to the other between queues, again choosing the route giving the shortest expected time in the system, given the queue lengths ahead of them.We find that Braess's paradox can occur: namely in equilibrium the expected transit time in the augmented network, for some service rates, can be greater than in the initial network.
On a best-choice problem by dependent criteria
Authors: Gnedin Alexander V. 
Published: April 2006

We study the problem of maximizing the probability of stopping at an object which is best in at least one of a given set of criteria, using only stopping rules based on the knowledge of whether the current object is relatively best in each of the criteria. The asymptotic results for the case of independent criteria are shown to hold in certain cases where the componentwise maxima are, pairwise, either asymptotically independent or asymptotically full dependent.An example of the former is a random sample from a bivariate correlated normal distribution; thus our results settle a question posed recently by T. S. Ferguson.
Inspection times for stand-by units
Authors: Parmigiani Giovanni 
Published: April 2006

This paper studies optimal timing of inspections for units in cold stand-by. The problem is approached in continuous time. The policies developed adapt optimally to information provided by failures of the main unit and by ageing of both the standby and the main unit.Results include a general form for the optimal policy, consisting of a recursive relation between successive inspection times, and of a renewal-type integral equation to determine the value of the objective function for a given policy. Further results are derived for the case in which the failure densities describing the process are logconcave. Then the stopping rule is easily characterized. It is also shown that the interval between inspections decreases with time, and that the optimal schedule is unique. A binary search algorithm for finding the solution is outlined.
Isolation of Intestinal Brush‐Border Membranes
Authors: Cheeseman Chris I , O'Neill Debbie 
Published: April 2006

AbstractThis unit provides protocols for isolating intestinal brush‐border membranes from rat, pig, and cow. These membranes can be used for immunoblotting or other analytical techniques. They will also spontaneously form closed vesicles which allow for flux assays to be performed using rapid filtration techniques. Overall the isolation procedures take ∼3.5 hr. The resulting isolated membranes can be stored under liquid nitrogen or at −70°C for a week or more depending upon the species.
Isolation and Characterization of Exosomes from Cell Culture Supernatants and Biological Fluids
Authors: Théry Clotilde , Amigorena Sebastian , Raposo Graça , Clayton Aled 
Published: April 2006

AbstractExosomes are small membrane vesicles found in cell culture supernatants and in different biological fluids. Exosomes form in a particular population of endosomes, called multivesicular bodies (MVBs), by inward budding into the lumen of the compartment. Upon fusion of MVBs with the plasma membrane, these internal vesicles are secreted. Exosomes possess a defined set of membrane and cytosolic proteins. The physiological function of exosomes is still a matter of debate, but increasing results in various experimental systems suggest their involvement in multiple biological processes. Because both cell‐culture supernatants and biological fluids contain different types of lipid membranes, it is critical to perform high‐quality exosome purification. This unit describes different approaches for exosome purification from various sources, and discusses methods to evaluate the purity and homogeneity of the purified exosome preparations.
Assessing vertical resolution requirements for operational weather radar data quality
Authors: Mittermaier Marion P. , Illingworth Anthony J. , Hogan Robin J. 
Published: April 2006

AbstractHigh‐resolution, 0.28° beamwidth range‐height‐indicator (RHI) data are used to simulate the reflectivities measured at various ranges by an operational radar with a 1° beamwidth. It is found that the sampling is optimal when the elevation increments equal the beamwidth. Larger increments lead to an unacceptable loss of information. Copyright © 2006 Royal Meteorological Society
Increased expression of nuclear factor E2 p45‐related factor 2 (NRF2) in head and neck squamous cell carcinomas
Authors: Stacy Donnie R. , Ely Kim , Massion Pierre P. , Yarbrough Wendell G. , Hallahan Dennis E. , Sekhar Konjeti R. , Freeman Michael L. 
Published: April 2006

AbstractBackground.Head and neck squamous cell carcinoma (HNSCC) continues to cause significant morbidity and mortality. Overexpression of specific phase II gene products may represent an important biomarker. One regulator of phase II gene expression is the transcription factor nuclear factor E2 p45‐related factor 2 (Nrf2). Nrf2 expression was evaluated in HNSCC, to determine whether it might serve as a biomarker for early detection of disease.Methods.A tissue microarray was constructed of 141 HNSCC biopsy cores from 47 HNSCCs. In addition, histologically normal squamous mucosa was obtained from 7 patients. Protein expression was evaluated by immunohistochemistry.Results.Nrf2 expression was increased in 91.5% of tumors. Expression of thioredoxin, a Nrf2‐reguated gene product, was elevated in 75% of tumors. Keap1, which regulates the rate of Nrf2 ubiquitination and degradation, was relatively overexpressed in HNSCC compared with normal mucosa.Conclusions.Nrf2 expression may be a possible HNSCC candidate biomarker. © 2006 Wiley Periodicals, Inc. Head Neck, 2006
The use of riparian vegetated filter strips to reduce river sediment loads: an overestimated control measure?
Authors: Verstraeten Gert , Poesen Jean , Gillijns Katleen , Govers Gerard 
Published: April 2006

AbstractThe spatially distributed soil erosion and sediment delivery model WATEM/SEDEM was used to simulate the impact of riparian vegetated filter strips (RVFSs) on river sediment delivery at different spatial scales. For a field plot with a straight slope, sediment reduction by the RVFSs is comparable to results obtained through experimental set‐ups elsewhere (i.e. >70%). However, at the scale of an entire catchment, sediment reduction is much less (i.e. ±20%) due to (1) overland flow convergence, which reduces the sediment trapping efficiency of an RVFS, and (2) because part of the sediment bypasses the RVFSs through ditches, sewers and road surfaces. These results suggest that, at the catchment scale, RVFSs should be accompanied with other conservation techniques that are more appropriate for reducing river sediment loads, and that also reduce on‐site soil erosion. Copyright © 2006 John Wiley & Sons, Ltd.
Macroporous and nanofibrous polymer scaffolds and polymer/bone‐like apatite composite scaffolds generated by sugar spheres
Authors: Wei Guobao , Ma Peter X. 
Published: April 2006

AbstractScaffolds are crucial to tissue engineering/regeneration. In this work, a technique combining a unique phase‐separation process with a novel sugar sphere template leaching process has been developed to produce three‐dimensional scaffolds. The resulting scaffolds possess high porosities, well connected macropores, and nanofibrous pore walls. The technique advantageously controls macropore shape and size by sugar spheres, interpore opening size by assembly conditions (time and temperature of heat treatment), and pore wall morphology by phase‐separation parameters. The bioactivity of a macroporous and nanofibrous poly(L‐lactic acid) (PLLA) scaffold was demonstrated by the bone‐like apatite deposition throughout the scaffold in a simulated body fluid (SBF). Preincorporation of nanosized hydroxyapatite eliminated the induction period and facilitated the apatite growth in the SBF. Interestingly, the apatite growth primarily occurred on the surface of the pores (internal and external) but not the interior of the nanofibrous network away from the pore surface. It was also noticed that the macropore size did not affect the apatite growth rate, while the interpore opening size did. The compressive modulus also increased substantially when a continuous apatite layer was formed on the pore walls of the scaffold. The resulting composite scaffold mimics natural bone matrix with the combination of an organic phase (a polymer such as PLLA) and an inorganic apatite phase. The demonstrated bioactivity of apatite layer, together with well‐controlled macroporous and nanofibrous structures, makes the novel nanocomposite scaffolds desirable for bone tissue engineering. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Copolymers containing a spiro orthoester moiety that undergo no shrinkage during cationic crosslinking
Authors: Kume Makoto , Hirano Atsunori , Ochiai Bungo , Endo Takeshi 
Published: April 2006

AbstractA spiro orthoester with an exomethylene group (exoSOE) was radically copolymerized with acrylonitrile or vinyl acetate at several feed ratios to obtain the corresponding copolymers having spiro orthoester moieties in the side chain. The obtained copolymers could be crosslinked via the double ring‐opening polymerization of the spiro orthoester moieties in their side chain by a treatment with BF3OEt2. The volume changes upon the crosslinking of the copolymers were evaluated by density measurements with a micromeritics gas pycnometer. The copolymers experienced less than 1% volume expansion instead of volume shrinkage during typical cationic crosslinking, regardless of the copolymer compositions. Negligible shrinkage was observed during the thermal cationic crosslinking of a film cast from a nitrobenzene solution of the copolymers containing a benzylthiophenium salt as a thermally latent cationic initiator. The constantly low volume changes during the crosslinking of the copolymers from exoSOE probably depended on the almost zero volume change during the cationic polymerizations of spiro orthoester derivatives. This indicates that exoSOE is an effective monomer for crosslinkable polymers without volume changes. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3666–3673, 2006
A multidimensional scaling analysis of the techniques that physiotherapists use
Authors: Turner Patricia A , Whitfield T W Allan 
Published: April 2006

AbstractFollowing the essentially ‘hands‐on’ origin of the physiotherapy profession a century ago, the range of techniques available to practitioners has expanded considerably. While this expansion of techniques has been of research interest, the main focus has been upon individual techniques, thus neglecting the fundamental question of the use of techniques in combination. In addition, researchers have tended to treat the profession as homogeneous, thus overlooking possible differences in technique usage. Copyright © 1997 Whurr Publishers Ltd.
Manipulation and four‐probe analysis of nanowires in UHV by application of four tunneling microscope tips: a new method for the investigation of electrical transport through nanowires
Authors: Lin Xiao , He Xiaobo , Lu Junling , Gao Li , Huan Qing , Deng Zhitao , Cheng Zhihai , Shi Dongxia , Gao Hongjun 
Published: April 2006

AbstractThe electrical transport properties of nanosystems, including a few kinds of nanowires, have attracted much attention because of their potential application in nanoelectronics. However, the contact effect or impurities between the nanosystems and electrodes made it difficult to study the intrinsic I–V properties in previous measurements. Here, we present a manipulation and four‐terminal method electrical transport measurement of low‐dimensional systems using a new instrument consisting of a specially designed tunneling microscope with four tips that can be positioned independently in three dimensions. The electrical conductivities of zinc oxide (ZnO), perylene, gallium sesquioxide (Ga2O3), and cuprum‐7,7′,8,8′‐tetracyanoquinodimethane (Cu‐TCNQ) nanowires were obtained. Our results have shown that this technique is a powerful tool for studying the intrinsic transport properties of nanosystems. Copyright © 2006 John Wiley & Sons, Ltd.
Nanodissection, isolation, and PCR amplification of single DNA molecules
Authors: Lü Junhong , An Hongjie , Li Haikuo , Li Xueling , Wang Ying , Li Minqian , Zhang Yi , Hu Jun 
Published: April 2006

AbstractA unique technique for positioning, dissection, and isolation of single DNA molecules using atomic force microscopy (AFM) has been demonstrated. Full‐length genome DNA molecules were first deposited and stretched by a modified ‘Molecular Combing’ technique on a 3‐aminopropyl triethoxysilane‐coated mica substrate. A single DNA fragment was dissected from individual genome DNA strands with the AFM tip at the desired position, and then isolated (or picked up) after a special operation called ‘kneading’. All the operations including imaging, dissection, and isolation could be carried out with one tip. The isolated DNA fragment on the AFM tip could be successfully amplified by single‐molecule PCR. Some of the physical and chemical mechanisms are discussed. Copyright © 2006 John Wiley & Sons, Ltd.
A poset hierarchy
Authors: Džamonja Mirna , Thompson Katherine 
Published: April 2006

AbstractThis article extends a paper of Abraham and Bonnet which generalised the famous Hausdorff characterisation of the class of scattered linear orders. They gave an inductively defined hierarchy that characterised the class of scattered posets which do not have infinite incomparability antichains (i.e. have the FAC). We define a larger inductive hierarchy κℌ* which characterises the closure of the class of all κ-well-founded linear orders under inversions, lexicographic sums and FAC weakenings. This includes a broader class of “scattered” posets that we call κ-scattered. These posets cannot embed any order such that for every two subsets of size < κ, one being strictly less than the other, there is an element in between. If a linear order has this property and has size κ it is unique and called ℚ(κ). Partial orders such that for every a < b the set {x: a < x < b} has size ≥ κ are called weakly κ-dense, and posets that do not have a weakly κ-dense subset are called strongly κ-scattered. We prove that κℌ* includes all strongly κ-scattered FAC posets and is included in the class of all FAC κ-scattered posets. For κ = ℵ0 the notions of scattered and strongly scattered coincide and our hierarchy is exactly aug(ℌ) from the Abraham-Bonnet theorem.
Using MODIS and AERONET to Determine GCM Aerosol Size
Authors: Lesins Glen , Lohmann Ulrike 
Published: April 2006

Abstract
Aerosol size is still a poorly constrained quantity in general circulation models (GCMs). By using the modal radii of the coarse and fine mode retrieved from 103 stations in the Aerosol Robotic Network (AERONET) and the fine mode aerosol optical depth fraction derived from both the Moderate Resolute Imaging Spectroradiometer (MODIS) Terra and AERONET, a globally and monthly averaged aerosol size distribution dataset was computed assuming internally mixed aerosols. Different methods were employed in creating the size distribution datasets that were input to the ECHAM4 climate model giving a globally averaged aerosol optical depth (AOD) at 500 nm that ranged from 0.11 to 0.20 depending on the method. This translates into a globally averaged direct aerosol top-of-atmosphere forcing range from −1.6 to −3.9 W m−2. Reducing the uncertainty in the aerosol sizes is important when using AOD to validate models since mass burden errors can then be assumed to be the main AOD error source. This paper explores a procedure that can help achieve this goal.
Transit-Time Distributions in a Global Ocean Model
Authors: Peacock Synte , Maltrud Mathew 
Published: April 2006

Abstract
Results from a simulation of the ocean “transit-time distribution” (“TTD”) for global and regional ocean surface boundary conditions are presented based on a 5000-yr integration using the Parallel Ocean Program ocean general circulation model. The TTD describes the probability that water at a given interior point in the ocean was at some point on the ocean surface a given amount of time ago. It is shown that the spatial distribution of ocean TTDs can be understood in terms of conventional wisdom regarding time scales and pathways of the ventilated thermocline and the thermohaline circulation–driven deep-ocean circulation. The true mean age from the model (the first moment of the TTD) is demonstrated to be very large everywhere, because of very long-tailed distributions. Regional TTD distributions are presented for distinct surface boundary subregions, and it is shown how these can help in the interpretation of the global TTD. The spatial structure of each regional TTD is shown to become essentially the same at relatively long times. The form of the TTD at a given point in the ocean can be very simple, but some regions do exhibit more complicated multimodal distributions. The degree to which a simple functional approximation to the TTD is able to predict the spatial and temporal evolution of selected idealized tracers (for which interior sources and sinks are known or zero) with knowledge of only the tracer surface boundary condition is explored.
The Operational JMA Nonhydrostatic Mesoscale Model
Authors: Saito Kazuo , Fujita Tsukasa , Yamada Yoshinori , Ishida Jun-ichi , Kumagai Yukihiro , Aranami Kohei , Ohmori Shiro , Nagasawa Ryoji , Kumagai Saori , Muroi Chiashi , Kato Teruyuki , Eito Hisaki , Yamazaki Yosuke 
Published: April 2006

Abstract
An operational nonhydrostatic mesoscale model has been developed by the Numerical Prediction Division (NPD) of the Japan Meteorological Agency (JMA) in partnership with the Meteorological Research Institute (MRI). The model is based on the MRI/NPD unified nonhydrostatic model (MRI/NPD-NHM), while several modifications have been made for operational numerical weather prediction with a horizontal resolution of 10 km. A fourth-order advection scheme considering staggered grid configuration is implemented. The buoyancy term is directly evaluated from density perturbation. A time-splitting scheme for advection has been developed, where the low-order (second order) part of advection is modified in the latter half of the leapfrog time integration. Physical processes have also been revised, especially in the convective parameterization and PBL schemes. A turbulent kinetic energy (TKE) diagnostic scheme has been developed to overcome problems that arise to predict TKE. The model performance for mesoscale NWP has been verified by comparison with a former operational hydrostatic mesoscale model of JMA. It is found that the new nonhydrostatic mesoscale model outperforms the hydrostatic model in the prediction of synoptic fields and quantitative precipitation forecasts.
On the asymptotic distributions of maxima of trigonometric polynomials with random coefficients
Authors: Turkman K. F. , Walker A. M. 
Published: April 2006

Let {εt,t =1, 2, ···,n} be a sequence of mutually independent standard normal random variables. LetXn(λ) andYn(λ) be respectively the real and imaginary parts ofexpiλt, and let. It is shown that asntends to∞, the distribution functions of the normalized maxima of the processes {Xn(λ)}, (Yn(λ)}, {In(λ)} over the interval λ∈ [0,π] each converge to the extremal distribution function exp [–e–x], —∞ <x<∞.It is also shown that these results can be extended to the case where {εt} is a stationary Gaussian sequence with a moving-average representation.
A note on stochastic bounds for queueing networks
Authors: Tsoucas Pantelis , Walrand Jean 
Published: April 2006

Recently, Massey [1] proved that the vector of queue lengths of some queueing networks is stochastically dominated at any given time by that of a corresponding system of parallel M/M/l queues. This result is interesting, even though the bounds are generally quite conservative, in that the transient behavior of independent parallel M/M/l queues is considerably easier to analyze than that of a network.This note provides an alternative proof of a generalized form of that result.