bluuebunny/crossref_metadata_2025 huggingface dataset:
Growth and survival patterns of Cardiocrinum cordatum var. glehnii (Liliaceae) based on a 13-year monitoring study: Life history characteristics of a monocarpic perennial herb
Authors: Araki Kiwako , Shimatani Kenichiro , Nishizawa Miyuki , Yoshizane Tomoko , Ohara Masashi
Published: August 2010

Based on 13 years of monitoring, the fates of individuals and contributions of size and age to demography through the life-history from seedling to flower were investigated in a monocarpic perennial herb, Cardiocrinum cordatum (Thunb.) Makino var. glehnii (F. Schmidt) H. Hara. Of 6155 seedlings, 5264 (85.5%) and 852 (13.8%) plants died at the seedling and one-leaf stage during the 13 years, respectively. Twelve individuals (0.40%) at the three- to seven-leaf stage reproduced after vegetative growth for 7–11 years, and all of them always showed constant positive growth patterns. Significant differences of sizes were detected between surviving and non-surviving individuals in earlier years at the one- and two-leaf stages. Logistic regression models showed that the survival and stage-increase probabilities increased until 5-years-old but decreased over 6-years-old, suggesting the significance of aging effects. At the four-leaf stage, the flowering probability increased with size, while it increased with leaf-stage but not size at greater stages. Individual growth models then suggested that many plants grew moderately: not only slow-growing but also rapidly-growing individuals tended to die within 7 years. Our study clarified three aspects of the life-history of C. cordatum: longevity of about a decade, constantly positive growth to flowering, and aging effects on growth and survival.
Designing marine reserves to reduce bycatch of mobile species: a case study using juvenile red snapper (Lutjanus campechanus)
Authors: Diamond Sandra L. , Kleisner Kristin M. , Duursma Daisy Englert , Wang Yuning
Published: August 2010

Marine reserves have not been widely used to conserve mobile species because species abundance levels can be highly variable over space and time. Here we explore the potential for marine reserves to reduce bycatch of mobile species using red snapper ( Lutjanus campechanus ) as a case study. Bycatch in Gulf of Mexico shrimp trawls is a major source of juvenile red snapper mortality, and marine reserves may be mandated if bycatch reduction targets are not met. Using geographic information system (GIS) analyses of fishery-independent data, we investigated whether red snapper juveniles concentrate in “hot spots” and examined the trade-offs between abundance within hot spots (intensity) and predictability over time (persistence). These trade-offs allow fishery managers to tailor marine reserves to meet specific conservation goals. For red snapper, hot spots were primarily located around the 30 m isobath, with hot spots spread along the Texas coast in fall and clustered around the Texas–Louisiana border in summer. Increased intensity of hot spots led to lower persistence due to the smaller spatial area of higher intensity hot spots. Hot spots moved annually but generally persisted in the same locations over time, indicating that marine reserves could reduce red snapper bycatch. This approach provides a foundation for making informed decisions about design and placement of reserves for mobile species.
Analytical solution for electron and lattice site temperatures due to laser-induced non-equilibrium energy transport in metals
Authors: Al-Theeb Hind M. , Yilbas Bekir S.
Published: August 2010

The present study describes the modeling of short-pulse laser heating of gold and copper materials. The energy transport due to a laser short pulse is formulated using the electron kinetic theory approach. Electron and lattice temperature distributions inside the substrate material during the laser short pulse are formulated analytically. In the analysis, the Laplace transformation technique is used. The results obtained from the analytical solutions are compared with numerical predictions and experimental data. It is found that the results obtained from the numerical and analytical solutions for temperature distributions are in good agreement with the experimental data.
Charged Dirac particle crossing a gravitational electromagnetic sandwich wave
Authors: Al-Badawi A. , abu Shayeb M. Kheare
Published: August 2010

The problem of a charged Dirac particle crossing a gravitational electromagnetic wave of finite duration in general relativity is considered in this paper. The set of equations representing the Dirac equation in the Newman–Penrose formalism is solved exactly. It is shown that the Dirac particle crossing such a wave emerges with amplified energy.
Local symmetry and Z-scan analysis of ZnSe/Eu3+ doped sol–gel silica hosts
Authors: Mathew Siby , Arun Kumar K. V. , Sudarsanakumar C. , Nampoori V. P.N. , Unnikrishnan N. V.
Published: August 2010

Vibrational state side-band spectral analysis of silica matrices, doped with ZnSe/Eu3+ ions, associated with the excitation transition 7F0→5D2 is used to analyze the local asymmetry of the rare earth ions in the glass host. The large inhomogeneous linewidth for the ZnSe co-doped samples indicates the wide distribution of the Eu3+ ions in the matrix and is related to the flexibility of the local glass network. The fluorescence spectra reveal that the intensity of the characteristic emission of europium increases considerably in the presence of ZnSe particles. This phenomenon can be explained by the energy transfer resulting from electron–hole recombination in the ZnSe to the rare earth ion. Nonlinear optical absorption of the sample is also investigated at a wavelength of 532 nm, using open aperture Z-scan technique. The sample exhibits reversible saturable absorption (RSA), which is found to depend on excitation fluence. RSA is due to the enhanced absorption resulting from the electron dynamics in nano-crystallites.
A tutorial on the precessional behaviour of hydrogen nuclei in external magnetic fields
Authors: Stafford Randall B. , Lauzon M. Louis , Sabati Mohammad , Frayne Richard , Thompson Robert I.
Published: August 2010

The purpose of this tutorial is to derive the precessional characteristics of the magnetic moments of hydrogen nuclei in the presence of a constant external magnetic field using the Dirac bra-ket formulation of quantum mechanics (QM). This behaviour has many applications, most notably in nuclear magnetic resonance (NMR) and magnetic resonance (MR) imaging. Many NMR and MR imaging textbooks claim that the QM expectation value of the magnetic moment of a proton in a magnetic field reduces to the classical picture of a precessing magnetic dipole. This paper validates this conclusion by reducing the cumbersome QM integrals using Dirac notation and matrix algebra, and then comparing this result with the classical picture. It illustrates the connections between the quantum and classical pictures and demonstrates quantitatively how they differ and how they are similar. This tutorial targets students and researchers interested in the fundamental physics behind the MR phenomenon and assumes that the reader has a basic understanding of QM. This may be helpful for undergraduate QM students learning about spin angular momentum and Dirac notation.
An independent-quark model calculation for radiative decay widths of mesons in static and beyond static approximation
Authors: Jena S. N. , Muni H. H. , Mohapatra P. K. , Panda P.
Published: August 2010

We perform a static calculation of decay widths for radiative transitions of mesons within the conventional picture of photon emission by a confined quark and (or) antiquark. As the calculation based on the moderate momentum transfer allows some amount of uncertainty to creep into the model predictions, we further apply the model for a more realistic calculation beyond the static approximation, taking into account some momentum-dependent effects due to the recoil of the daughter meson. The results obtained for the decay widths of radiative transitions of light mesons are improved and are in good agreement with the experimental values. The predictions on the decay rates of heavy mesons are also affected and are comparable with those of other model predictions.
Pionic contribution to relativistic Fermi liquid parameters
Authors: Pal Kausik
Published: August 2010

We calculate pionic contribution to the relativistic Fermi liquid parameters (RFLPs) using a chiral effective Lagrangian. The RFLPs so determined are then used to calculate chemical potential, exchange and nuclear symmetry energies due to πN interaction. We also evaluate two loop ring diagrams involving σ, ω, and π meson exchanges and compare results with what one obtains from the relativistic Fermi liquid theory (RFLT).
Sampling gap fraction and size for estimating leaf area and clumping indices from hemispherical photographs
Authors: Gonsamo Alemu , Walter Jean-Michel N. , Pellikka Petri
Published: August 2010

Hemispherical photography is becoming a popular technique for gap fraction measurements to characterize biophysical parameters and solar radiation in plant canopies. One of the crucial steps in the measurement of canopy gap fraction using hemispherical photography is determining the resolution of the sampling grid. In this work, the effects of varying resolutions of sampling grids by modifying the angle widths of zenithal annuli and azimuthal sectors were evaluated for leaf area and clumping indices computations. Sensitivity analysis was performed to test these effects using artificial photographs simulating ideal canopies with varying leaf area index and aggregation levels of foliage elements. Contrasting forest types, including natural tropical cloud forest and exotic plantations, were tested as real canopies. Results indicate that leaf area and clumping indices estimates are significantly affected by the variation of sampling grids. A new approach to solve the problem of null-gap segments, obscured completely by foliage, is proposed. However, the determination of optimal combinations of zenithal annuli and azimuthal sector angular widths that suit all canopy types remains a difficult practical problem that is often overlooked. Finally, theoretically sound gap fraction and size sampling regions were demonstrated for reliable estimates of canopy biophysical parameters.
Contributions of harvest slash to maintaining downed woody debris in selection-managed forests
Authors: Vanderwel Mark C. , Thorpe Hilary C. , Caspersen John P.
Published: August 2010

Harvest slash can represent a major source of downed woody debris (DWD) in selection-managed forests. In this study, we analyze the volume, cover, size distribution, and decay-class distribution of DWD input by selection harvesting in central Ontario, Canada. Selection harvesting input 23.9 m3 DWD·ha–1 (0.013 m2 DWD·m–2), with cut basal area explaining 46% and 30% of the respective within-stand variation in cover and volume, respectively. The size distribution of the slash was similar to that of DWD in permanent sample plots (including old-growth stands and stands that have not been recently harvested), countering a common assumption that harvesting inputs only small-sized material. Harvest-origin DWD was bimodally distributed across decay classes, with the first peak (decay class 1) associated with fresh harvest slash and a second smaller peak (decay class 3) likely representing dead trees and branches that were felled or broken during harvest operations. A matrix projection model showed that slash can maintain DWD levels in managed, uneven-aged stands comparable with those in unmanaged stands, but the mean decay class increases steadily over a 20-year period after harvest. Our results underline the importance of harvest inputs for maintaining DWD pools in selection-managed forests and provide baseline information against which to compare forests managed with higher utilization standards.
Tree-ring evidence of larch sawfly outbreaks in western Labrador, Canada
Authors: Nishimura Peter H. , Laroque Colin P.
Published: August 2010

As many insect outbreak reconstructions are typically based on targeted single-site sampling, researchers have often been limited in their ability to draw conclusions about regional trends as opposed to local trends in the data. The results of this paper demonstrate the value of a systematic sampling design when studying spatio-temporal processes that can vary greatly within large continuous areas of forest. Many single-site research programs have been conducted to reconstruct the history of larch sawfly ( Pristiphora erichsonii Htg.) outbreaks in the eastern boreal region of North America. However, no such research has yet been conducted in the region of Labrador. In an attempt to illustrate the strength of a systematic gridded sampling protocol over a single-site study, we sampled a 12-site grid in western Labrador. Dominant and codominant species were sampled at each grid point, resulting in 24 master chronologies. Six eastern larch ( Larix laricina (Du Roi) K. Koch) chronologies (host) and a regional black spruce ( Picea mariana (Mill.) Britton, Sterns, Poggenb.) chronology (nonhost) were used to establish a host–nonhost analysis of past sawfly outbreaks on a regional scale. Both regional and localized larch sawfly outbreaks were identified, but in general, larch sawfly outbreaks in western Labrador appeared to be spatially synchronous and regional in scale.
Breeding against dothistroma needle blight of radiata pine in Australia
Authors: Ivković Miloš , Baltunis Brian , Gapare Washington , Sasse Jo , Dutkowski Gregory , Elms Stephen , Wu Harry
Published: August 2010

Pine needle blight, caused by Dothistroma septosporum (Dorog.) M. Morelet, is one of the most serious foliar diseases of Pinus spp. in Australia and New Zealand. In 16 Pinus radiata (D.Don.) progeny trials in northeastern Victoria, Australia, Dothistroma-caused defoliation varied widely among trials and assessment years, ranging from 5% to 65%. The estimated narrow sense heritability ranged from nonsignificant to as high as 0.69 with a median of 0.36. Spatial autocorrelation of residuals accounted for a significant proportion of residual variance, and that increased heritability estimates. Genetic correlation between defoliation scores at an early age and growth at a later age was negative with a median value of –0.39. Phenotypic correlation between defoliation and survival was low and negative with a median value of –0.11. Economic analyses indicated that at sites with a high risk of infection, the effect of reducing defoliation on profitability was comparable with that of increasing growth at sites free from infection. The genetic parameters and economic impacts of Dothistroma were used to derive selection indices and include resistance to defoliation into the current breeding objective for radiata pine.
Effect of growth suppression and release on strength and specific gravity of yellow-poplar
Authors: Mettanurak Thammarat , Zink-Sharp Audrey , Copenheaver Carolyn A. , Zedaker Shepard M.
Published: August 2010

Compression tests and specific gravity analyses were conducted to investigate the impacts of growth suppression and growth release on wood quality in yellow-poplar ( Liriodendron tulipifera L.). Growth ring widths in 23 increment cores were determined and the years of minimum suppression and maximum release were identified based on a modified radial growth averaging technique. Three specimens (1 mm × 1 mm × 4 mm) from both minimum suppression and maximum release years were prepared from each increment core. Data analysis using paired-samples t tests revealed that the mean ultimate crushing stress of the maximum release years was significantly higher than that of the minimum suppression years, yet the mean specific gravity was not significantly different. Even though there was no statistical difference in specific gravity for the two growth conditions studied, the ultimate crushing stress was statistically higher for the release growth specimens. This finding provides support for the concept that growth rate can have an added effect on strength properties that is not entirely captured by specific gravity. Thus, to improve wood quality in yellow-poplar stands, forest managers might consider increasing the likelihood of periods of growth release by controlling the competition experienced by the trees.
Determinants and modeling of specific dynamic action for the Common Garter Snake (Thamnophis sirtalis)
Authors: Bessler Scott M. , Stubblefield Mary C. , Ultsch G. R. , Secor Stephen M.
Published: August 2010

Specific dynamic action (SDA), the cumulative energy expended on digestion and assimilation, can contribute significantly to individual daily energy expenditure (DEE). The Common Garter Snake (Thamnophis sirtalis (L., 1758)) is a widely distributed generalist predator that could experience considerable variation in SDA and hence the contribution of SDA to DEE. We examined the effects of meal size, meal type, and body temperature on the postprandial metabolic response and SDA of the Eastern Garter Snake ( Thamnophis sirtalis sirtalis (L., 1758)) and generated predictive models of SDA based on meal size, body mass, and body temperature, and separately based on meal energy. Postprandial peak in oxygen consumption, duration of significantly elevated oxygen consumption, and SDA increased with increasing meal size (5%–45% of body mass). Postprandial metabolic response digesting six different equal-size prey items varied significantly; vertebrate prey generated larger SDA responses than soft-bodied invertebrates. Increases in experimental temperature (15–35 °C) yielded a matched increase in postprandial peak in oxygen consumption and decrease in digestive duration. For a 1-month hypothetical feeding history for an adult T. sirtalis, the cumulative predicted SDA varied by 4.5% among the three models (minimal, intermediate, and maximal intake of prey) and averaged 8%, 22%, and 38% of DEE, respectively.
LEARNING EYE VERGENCE CONTROL FROM A DISTRIBUTED DISPARITY REPRESENTATION
Authors: CHUMERIN NIKOLAY , GIBALDI AGOSTINO , SABATINI SILVIO P. , VAN HULLE MARC M.
Published: August 2010

We present two neural models for vergence angle control of a robotic head, a simplified and a more complex one. Both models work in a closed-loop manner and do not rely on explicitly computed disparity, but extract the desired vergence angle from the post-processed response of a population of disparity tuned complex cells, the actual gaze direction and the actual vergence angle. The first model assumes that the gaze direction of the robotic head is orthogonal to its baseline and the stimulus is a frontoparallel plane orthogonal to the gaze direction. The second model goes beyond these assumptions, and operates reliably in the general case where all restrictions on the orientation of the gaze, as well as the stimulus position, type and orientation, are dropped.
COUPLED SINGULAR VALUE DECOMPOSITION OF A CROSS-COVARIANCE MATRIX
Authors: KAISER ALEXANDER , SCHENCK WOLFRAM , MÖLLER RALF
Published: August 2010

We derive coupled on-line learning rules for the singular value decomposition (SVD) of a cross-covariance matrix. In coupled SVD rules, the singular value is estimated alongside the singular vectors, and the effective learning rates for the singular vector rules are influenced by the singular value estimates. In addition, we use a first-order approximation of Gram-Schmidt orthonormalization as decorrelation method for the estimation of multiple singular vectors and singular values. Experiments on synthetic data show that coupled learning rules converge faster than Hebbian learning rules and that the first-order approximation of Gram-Schmidt orthonormalization produces more precise estimates and better orthonormality than the standard deflation method.
BOUNCING UNIVERSE AND PHANTOM CROSSING IN MODIFIED GRAVITY AND ITS RECONSTRUCTION
Authors: FARAJOLLAHI HOSSEIN , MILANI FARZAD
Published: August 2010

In this paper we consider FRW cosmology in modified gravity which contains arbitrary functions f(ϕ). It is shown that the bouncing solution appears in the model whereas the equation of state (EoS) parameter crosses the phantom divider. The reconstruction of the model is also investigated with the aim to reconstruct the arbitrary functions and variables of the model.
EXACT SOLUTION OF DIRAC EQUATION FOR MIE-TYPE POTENTIAL BY USING THE NIKIFOROV–UVAROV METHOD UNDER THE PSEUDOSPIN AND SPIN SYMMETRY LIMIT
Authors: HAMZAVI M. , HASSANABADI H. , RAJABI A. A.
Published: August 2010

Dirac equation is solved for Mie-type potential. The energy spectra and the corresponding wave functions are investigated with pseudospin and spin symmetry. The Nikiforov–Uvarov method is used to obtain an analytical solution of the Dirac equation and closed forms of energy eigenvalues are obtained for any spin-orbit coupling term κ. We also present some numerical results of Dirac particles for the well-known Kratzer–Fues and modified Kratzer potentials which are Mie-type potential.
QUANTIFICATION AND THE UNDERLYING MECHANISM OF SKIN THERMAL DAMAGE: A REVIEW
Authors: XU F. , WANG P. F. , LIN M. , LU T. J. , NG E. Y. K.
Published: August 2010

Skin thermal damage is the most common thermal trauma in civilian and military communities. Besides, advances in laser, microwave, and similar technologies have led to recent developments of thermal treatments for diseases involving skin tissue aiming at inducing damage precisely within targeted tissue structures without affecting the surrounding healthy tissue. Pain sensation accompanying thermal damage is also a serious problem for burn patients. Therefore, it is of great importance to quantify the thermal damage in skin tissue. In this review, we detail the progress of the state-of-the-art mathematical models and experimental methods for the quantification of thermal damage (both heat damage and cold damage) and the general development of thermal treatments in tissue engineering. This could enable better understanding of the underlying mechanisms of skin thermal damage and the optimization of clinical thermal therapies.
EFFECTS OF THE WALL STRESS–STRAIN NONLINEARITY AND VISCOELASTICITY IN A STENTED VESSEL
Authors: KOL G. R. , NTCHANTCHO R. , WOAFO P.
Published: August 2010

In this work, we study the behavior of the outflow of an incompressible viscous Newtonian fluid in large vessels with the presence of a stent having a nonlinear stress–strain relation. Here, we present a mathematical approach that allows us to get analytical solutions of the bidimensional flow in elastic stented vessel proportional to the mean axial flow. Thereafter, the one-dimensional (1D) model is obtained by averaging the two-dimensional (2D) incompressible Navier–Stokes equations over the radius of the vessel. We use the perturbative approach to solve the 1D approximation finally obtained, which helps to deduce the results of the final analytical solutions. The numerical simulation then helps to evaluate the effects of the stiffness, the nonlinearity of the wall, and the viscoelasticity of the stented vessel. We show that the increase of stiffness and nonlinearity of the stented vessel cause the distortions to the level of the swelling zones of prosthesis that contributes to reduce the life span of the stent and damages of the wall.
A NUMERICAL SIMULATION OF CARDIAC ELECTRIC ACTIVITY IN LV BASED ON MONO-DOMAIN MODEL
Authors: RATHISH KUMAR B. V. , PATHAK S. K. , SANGWAN VIVEK , NIGAM MOHIT , MURTHY S. K.
Published: August 2010

Heterogeneities of ionic current expression and electrophysiological characteristics exist within the mammalian ventricle wall and are assumed to be the result of regional differences in myocardial membrane ionic current densities. This work describes computational approaches of modeling the cardiac cellular excitability and electrical activity propagation in the spatially inhomogeneous ventricular tissue. A three-dimensional (3D) unsteady Rogers model with one gating variable has been considered for simulating the cardiac electrical activity. Based on the paradigm of domain decomposition a 3D finite element scheme has been developed and implemented using PETSc Library under MPI environment. The numerical simulations are carried out on IBM SP3 machine. The computational studies provide insight into the underlying mechanisms during the normal and pathological cardiac excitation.
RaPTEX
Authors: Lim Jun Bum , Jang Beakcheol , Yoon Suyoung , Sichitiu Mihail L. , Dean Alexander G.
Published: August 2010

Advances in microprocessors, memory, and radio technology have enabled the emergence of embedded systems that rely on communication systems to exchange information and coordinate their activities in spatially distributed applications. However, developing embedded communication systems that satisfy specific application requirements is a challenge due to the many tradeoffs imposed by different choices of underlying protocols and their parameters. Furthermore, evaluating the correctness and performance of the design and implementation before deploying it is a nontrivial task due to the complexity of the resulting system. This article presents the design and implementation of RaPTEX, a rapid prototyping tool for embedded communication systems, especially well suited for wireless sensor networks (WSNs), consisting of three major subsystems: a toolbox, an analytical performance estimation framework, and an emulation environment. We use a hierarchical approach in the design of the toolbox to facilitate the composition of the network stack. For fast exploration of the tradeoff space at design time, we build an analytical performance estimation model for energy consumption, delay, and throughput. For realistic performance evaluation, we design and implement a hybrid, accurate, yet scalable, emulation environment. Through three use cases, we study the tradeoff space for different protocols and topologies, and highlight the benefits of using RaPTEX for designing and evaluating embedded communication systems for WSNs.
Stabilizing trust and reputation for self-stabilizing efficient hosts in spite of byzantine guests
Authors: Dolev Shlomi , Yagel Reuven
Published: August 2010

This work presents a general and complete method to protect a system against possible malicious programs. We provide concepts for building a system that can automatically recover from an arbitrary state including even one in which a Byzantine execution of one or more programs repeatedly attempts to corrupt the system state. Preservation of a guest execution is guaranteed as long as the guest respects a predefined contract, while efficiency is improved by using stabilizing reputation. We augment a provable self-stabilizing host operating system implementation with a contract-enforcement framework example.
Scalable concurrent hash tables via relativistic programming
Authors: Triplett Josh , McKenney Paul E. , Walpole Jonathan
Published: August 2010

This paper presents a novel concurrent hash table implementation which supports wait-free, near-linearly scalable lookup, even in the presence of concurrent modifications. In particular, this hash table implementation supports concurrent moves of hash table elements between buckets, for purposes such as renames.

Implementation of this algorithm in the Linux kernel demonstrates its performance and scalability. Benchmarks on a 64-way POWER system showed a 6x scalability improvement versus fine-grained locking, and a 1.5x improvement versus the current state of the art in Linux.

To achieve these scalability improvements, the hash table implementation uses a new concurrent programming technique known as
relativistic programming
. This approach uses a copy-based update strategy to allow readers and writers to run concurrently without conflicts, avoiding many of the non-scalable costs of synchronization, inter-processor communication, and cache coherence. New techniques such as the proposed hash-table move algorithm allow readers to tolerate the resulting weak memory-ordering behavior that arises from allowing one version of a structure to be read concurrently with updates to a different version of the same structure. Relativistic programming techniques provide performance and scalability advantages over traditional synchronization, as demonstrated through several benchmarks.
Connecting the dots
Authors: Roda Giovanna
Published: August 2010

Symbolic Computation is an area of computer science that after 20 years of initial research had its acme in the mid-1980s, when its many new algorithms were made available in "math systems for the masses" like Mathematica and Maple. Computational algebra and computational logic are the two main pillars on which this discipline is based.

Currently, the field experiences a new blossom by the integration and combination of new numeric, algebraic, geometric and logic algorithms made available in new, interactive and easy-to-use versions of these systems combined with web services. Spectacular new applications are reported in areas so different as elementary particle physics, cryptography, and automated software generation. One of the most outstanding outcomes of Symbolic Computation is the recently born Wolfram Alpha system, fully programmed in Mathematical.

The goal of this writing is to remind the Information Retrieval community of the chances and capabilities offered by Symbolic Computation.
Event and map content personalisation in a mobile and context-aware-environment
Authors: Bierig Ralf
Published: August 2010

Effective methods for information access are of the greatest importance for our modern lives -- particularly with respect to handheld devices. Personalisation is one such method which models a user's characteristics to deliver content more focused to the user's needs. The emerging area of sophisticated mobile computing devices has started to inspire new forms of personalised systems that include aspects of the person's contextual environment. This thesis seeks to understand the role of personalisation and context, to evaluate the effectiveness of context for content personalisation and to investigate the event and map content domain for mobile usage. The work presented in this thesis has three parts.

The
first part
is a user experiment on context that investigated the contextual attributes of time, location and interest, with respect to participants' perception of their usefulness. Results show highly dynamic and interconnected effects of context on participants' usefulness ratings.

In the
second part
, these results were applied to create a predictive model of context that was related to attribution theory and then combined with an information retrieval score to create a weighted personalisation model.

In the
third part
of this work, the personalisation model was applied in a mobile experiment. Participants solved situational search tasks using a (i) non-personalized and a (ii) personalized mobile information system, and rating entertainment events based on usefulness. Results showed that the personalised system delivered about 20% more useful content to the mobile user than the non-personalised system, with some indication for reduced search effort in terms of time and the amount of queries per task.

The work presented provides evidence for the promising potential of context to facilitate personalised information delivery to users of mobile devices. Overall, it serves as an example of an investigation into the effectiveness of context from multiple angles and provides a potential link to some of the aspects of psychology as a potential source for a deeper understanding of contextual processes in humans.
The absence of LPA receptor 2 reduces the tumorigenesis by ApcMin mutation in the intestine
Authors: Lin Songbai , Lee Sei-Jung , Shim Hyunsuk , Chun Jerold , Yun C. Chris
Published: August 2010

Lysophosphatidic acid (LPA) is a lipid mediator that mediates several effects that promote cancer progress. The LPA receptor type 2 (LPA2) expression is often elevated in several types of cancers, including colorectal cancer (CRC). In this study, we investigated the role of LPA2 in the development of intestinal adenomas by comparing Apc Min/+ mice with Apc Min/+ /Lpar2 −/− mice. There were 50% fewer intestinal adenomas in Apc Min/+ /Lpar2 −/− mice than Apc Min/+ mice. Smaller-size adenomas (<1 mm) were found at higher frequencies in Apc Min/+ /Lpar2 −/− mice compared with Apc Min/+ mice at the two age groups examined. The expression level of LPA2 correlated with increased size of intestinal adenomas. Reduced tumor multiplicity and size in Apc Min/+ /Lpar2 −/− mice correlated with decreased proliferation of intestinal epithelial cells. Apc Min/+ /Lpar2 −/− mice showed an increased level of apoptosis, suggesting that LPA2-mediated signaling stimulates intestinal tumor development and progress by regulating both cell proliferation and survival. In addition, the expression levels of Krüpple-like factor 5 (KLF5), β-catenin, cyclin D1, c-Myc, and hypoxia-inducible factor-1α (HIF-1α) were significantly altered in Apc Min/+ /Lpar2 −/− mice compared with Apc Min/+ mice. In vitro studies using HCT116 cells showed that LPA induced cyclin D1, c-Myc, and HIF-1α expression, which was attenuated by knockdown of LPA2. In summary, intestinal tumor initiated by Apc mutations is altered by LPA2-mediated signaling, which regulates tumor growth and survival by altering multiple targets.
Nucleus raphé pallidus participates in midbrain-medullary cardiovascular sympathoinhibition during electroacupuncture
Authors: Li Peng , Tjen-A-Looi Stephanie C. , Longhurst John C.
Published: August 2010

We have shown that electroacupuncture (EA) inhibits sympathoexcitatory rostral ventrolateral medulla (rVLM) neurons and reflex responses following activation of a long-loop pathway in the arcuate nucleus and ventrolateral periaqueductal gray (vlPAG). Additionally, EA at P 5–6 acupoints (overlying the median nerve) activates serotonin-containing neurons in the nucleus raphé pallidus (NRP), which, in turn, inhibit rVLM neurons. Although direct projections from the vlPAG to the rVLM exist, it is uncertain whether an indirect pathway through the NRP serves an important role in vlPAG-rVLM cardiovascular modulation. Therefore, the splanchnic nerve (SN) was stimulated to induce cardiovascular sympathoexcitatory reflexes, and EA was applied at P 5–6 acupoints in α-chloralose-anesthetized cats. A single-barreled recording electrode was inserted into the NRP or rVLM. Microinjection of dl-homocysteic acid (DLH) into the vlPAG increased the NRP neuronal response to SN stimulation (5 ± 1 to 12 ± 2 spikes/30 stim). Likewise, EA at P 5–6 for 30 min increased the NRP response to SN stimulation (3 ± 1 to 10 ± 2 spikes/30 stim), an effect that could be blocked by microinjection of kynurenic acid (KYN) into the caudal vlPAG. Furthermore, the reflex increase in blood pressure induced by application of bradykinin to the gallbladder and the rVLM cardiovascular presympathetic neuronal response to SN stimulation was inhibited by injection of DLH into the vlPAG, a response that was reversed by injection of KYN into the NRP. These results indicate that EA activates the vlPAG, which excites the NRP to, in turn, inhibit rVLM presympathetic neurons and reflex cardiovascular sympathoexcitatory responses.
PGC-1α increases PDH content but does not change acute PDH regulation in mouse skeletal muscle
Authors: Kiilerich Kristian , Adser Helle , Jakobsen Anne H. , Pedersen Per A. , Hardie D. Grahame , Wojtaszewski Jorgen F. P. , Pilegaard Henriette
Published: August 2010

The aim of this study was to test whether the transcriptional coactivator peroxisome proliferator-activated receptor (PPAR)-γ coactivator (PGC)1α regulates the content of pyruvate dehydrogenase (PDH)-E1α and influences PDH activity through regulation of pyruvate dehydrogenase kinase-4 (PDK4) expression and subsequently PDH phosphorylation. PGC-1α whole body knockout (KO), muscle-specific PGC-1α overexpressing mice (MCK PGC-1α), and littermate wild-type (WT) mice underwent two interventions known to affect PDH. Quadriceps muscles were removed from fed and 24-h fasted mice as well as at 6 h of recovery after 1-h running and from mice that did not run acutely. PDH-E1α protein content and PDH-E1α phosphorylation were lower in PGC-1α KO and higher in MCK PGC-1α mice at rest, but, while MCK PGC-1α had higher PDK4 protein content, KO of PGC-1α had no effect on PDK4 protein content. The differences in phosphorylation partly vanished when expressing phosphorylation relative to the PDH-E1α content with only a maintained elevated phosphorylation in MCK PGC-1α mice. Fasting upregulated PDK4 protein in PGC-1α KO, MCK PGC-1α and WT mice, but this was not consistently associated with increased PDH-E1α phosphorylation. Downregulation of the activity of PDH in the active form (PDHa) at 6-h recovery from exercise in both the PGC-1α KO and MCK PGC-1α mice and the association between PDH-E1α phosphorylation and PDHa activity in PGC-1α KO mice indicate that PGC-1α is not required for these responses. In conclusion, PGC-1α regulates PDH-E1α protein content in parallel with mitochondrial oxidative proteins, but does not seem to influence PDH regulation in mouse skeletal muscle in response to fasting and in recovery from exercise.
Adding a statin to a combination of ACE inhibitor and ARB normalizes proteinuria in experimental diabetes, which translates into full renoprotection
Authors: Zoja Carla , Corna Daniela , Gagliardini Elena , Conti Sara , Arnaboldi Lorenzo , Benigni Ariela , Remuzzi Giuseppe
Published: August 2010

The capacity of renin-angiotensin system (RAS) inhibitors to delay progression of diabetic nephropathy depends on the time at which therapy is started. A multimodal intervention is required to afford renoprotection in overt diabetic nephropathy. Here we assessed the effects of maximal RAS inhibition by angiotensin-converting enzyme (ACE) inhibitor plus angiotensin II type 1 receptor blocker (ARB) in combination with statin in rats with overt diabetic nephropathy. Uninephrectomized rats made diabetic by streptozotocin were orally treated from 4 (when proteinuria and renal lesions had developed) to 8 mo with vehicle, lisinopril plus candesartan, lisinopril plus candesartan plus rosuvastatin, or rosuvastatin alone. Systolic blood pressure increased in diabetic rats and was significantly lowered by combined therapies. Dual RAS blockade significantly reduced proteinuria compared with vehicle. Addition of statin further lowered proteinuria to control levels. Glomerulosclerosis was ameliorated by RAS inhibitors or statin, and regression was achieved by the addition of statin. Loss of podocytes of diabetic rats was limited by ACE inhibitor plus ARB while normalized by the three drugs. Defective nephrin expression of diabetes was increased by dual RAS blockade or statin and restored by the triple therapy. Tubular damage, interstitial inflammation, and expression of the fibrotic markers transforming growth factor (TGF)-β1 and phosphorylated Smad 2/3 in tubuli were significantly reduced by the triple regimen. These data suggest a strategy to target proteinuria to try to achieve regression of renal disease in diabetic patients who do not fully benefit from RAS inhibition alone.
Cytoglobin, a novel globin, plays an antifibrotic role in the kidney
Authors: Mimura Imari , Nangaku Masaomi , Nishi Hiroshi , Inagi Reiko , Tanaka Tetsuhiro , Fujita Toshiro
Published: August 2010

Cytoglobin (Cygb), a novel member of the globin superfamily, is expressed by fibroblasts in various organs. However, its function remains unknown. Because of its localization, we speculated that a biological role of Cygb may be related to fibrogenesis. To clarify the role of Cygb in kidney fibrosis, we employed the remnant kidney model in rats. Immunohistochemical analysis showed an increase in Cygb expression in parallel with disease progression. To investigate the functional consequence of Cygb upregulation, we established transgenic rats overexpressing rat Cygb. Overexpression of Cygb improved histological injury, preserved renal function, and ameliorated fibrosis, as estimated by the accumulation of collagen I and IV as well as Masson trichrome staining. These protective effects of Cygb were associated with a decrease in nitrotyrosine deposition in the kidney and urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG) excretion as a marker of oxidative stress. We also performed in vitro studies utilizing a rat kidney fibroblast cell line transiently overexpressing Cygb, an inducible kidney cell transfected with Cygb, and primary cultured fibroblasts isolated from the kidneys of the transgenic rats. These different experimental systems consistently showed that Cygb inhibited collagen synthesis. Furthermore, mutant disruption of heme in Cygb that impaired its antioxidant properties led to the loss of antifibrotic effects, suggesting that Cygb reduces fibrosis via a radical scavenging function. In conclusion, we showed that Cygb plays an important role in protection of the kidney against fibrosis via the amelioration of oxidative stress both in vitro and in vivo. Cygb might represent a good therapeutic target in chronic kidney disease.
Ca2+-Dependent and Na+-Dependent K+ Conductances Contribute to a Slow AHP in Thalamic Paraventricular Nucleus Neurons: A Novel Target for Orexin Receptors
Authors: Zhang Li , Kolaj Miloslav , Renaud Leo P.
Published: August 2010

Thalamic paraventricular nucleus (PVT) neurons exhibit a postburst apamin-resistant slow afterhyperpolarization (sAHP) that is unique to midline thalamus, displays activity dependence, and is abolished in tetrodotoxin. Analysis of the underlying s IAHP confirmed a requirement for Ca2+ influx with contributions from P/Q-, N-, L-, and R subtype channels, a reversal potential near EK+ and a significant reduction by UCL-2077, barium or TEA, consistent with a role for KCa channels. s IAHP was significantly reduced by activation of either the cAMP or the protein kinase C (PKC) signaling pathway. Further analysis of the sAHP revealed an activity-dependent but Ca2+-independent component that was reduced in high [K+]o and blockable after Na+ substitution with Li+ or in the presence of quinidine, suggesting a role for KNa channels. The Ca2+-independent sAHP component was selectively reduced by activation of the PKC signaling pathway. The sAHP contributed to spike frequency adaptation, which was sensitive to activation of either cAMP or PKC signaling pathways and, near the peak of membrane hyperpolarization, was sufficient to cause de-inactivation of low threshold T-Type Ca2+ channels, thus promoting burst firing. PVT neurons are densely innervated by orexin-immunoreactive fibers, and depolarized by exogenously applied orexins. We now report that orexin A significantly reduced both Ca2+-dependent and -independent s IAHP, and spike frequency adaptation. Furthermore orexin A-induced s IAHP inhibition was mediated through activation of PKC but not PKA. Collectively, these observations suggest that KCa and KNa channels have a role in a sAHP that contributes to spike frequency adaptation and neuronal excitability in PVT neurons and that the sAHP is a novel target for modulation by the arousal- and feeding-promoting orexin neuropeptides.
Endogenous Inhibition of the Trigeminally Evoked Neurotransmission to Cardiac Vagal Neurons by Muscarinic Acetylcholine Receptors
Authors: Gorini C. , Philbin K. , Bateman R. , Mendelowitz D.
Published: August 2010

Stimulation of the nasal mucosa by airborne irritants or water evokes a pronounced bradycardia accompanied by peripheral vasoconstriction and apnea. The dive response, which includes the trigeminocardiac reflex, is among the most powerful autonomic responses. These responses slow the heart rate and reduce myocardial oxygen consumption. Although normally cardioprotective, exaggeration of this reflex can be detrimental and has been implicated in cardiorespiratory diseases, including sudden infant death syndrome (SIDS). An essential component of the diving response and trigeminocardiac reflex is activation of the parasympathetic cardiac vagal neurons (CVNs) in the nucleus ambiguus that control heart rate. This study examined the involvement of cholinergic receptors in trigeminally evoked excitatory postsynaptic currents in CVNs in an in vitro preparation from rats. CVNs were identified using a retrograde tracer injected into the fat pads at the base of the heart. Application of the acetylcholinesterase inhibitor neostigmine significantly decreased the amplitude of glutamatergic neurotransmission to CVNs on stimulation of trigeminal fibers. Whereas nicotine did not have any effect on the glutamatergic responses, the muscarinic acetylcholine receptor (mAChR) agonist bethanechol significantly decreased the excitatory neurotransmission. Atropine, an mAChR antagonist, facilitated these responses indicating this trigeminally evoked brain stem pathway in vitro is endogenously inhibited by mAChRs. Tropicamide, an m4 mAChR antagonist, prevented the inhibitory action of the muscarinic agonist bethanechol. These results indicate that the glutamatergic synaptic neurotransmission in the trigeminally evoked pathway to CVNs is endogenously inhibited in vitro by m4 mAChRs.
BDNF Evokes Release of Endogenous Cannabinoids at Layer 2/3 Inhibitory Synapses in the Neocortex
Authors: Lemtiri-Chlieh Fouad , Levine Eric S.
Published: August 2010

The neurotrophin brain-derived neurotrophic factor (BDNF) is a potent regulator of inhibitory synaptic transmission, although the locus of this effect and the underlying mechanisms are controversial. We explored a potential interaction between BDNF and endogenous cannabinoid (endocannabinoid) signaling because activation of type 1 cannabinoid (CB1) receptors potently regulates γ-aminobutyric acid (GABA) release and both trkB tyrosine kinase receptors and CB1 receptors are highly expressed at synapses in neocortical layer 2/3. Here, we found that the effects of BDNF at inhibitory cortical synapses are mediated by the release of endocannabinoids acting retrogradely at presynaptic CB1 receptors. Specifically, acute application of BDNF rapidly reduced the amplitude of inhibitory postsynaptic currents (IPSCs) via postsynaptic trkB receptor activation because intracellular delivery of the tyrosine kinase inhibitor K252a completely blocked the BDNF effect. Although triggered by postsynaptic trkB activation, BDNF exposure decreased presynaptic release probability, as evidenced by increases in the paired-pulse ratio and coefficient of variation of evoked responses. In addition, BDNF decreased the frequency but not the amplitude of action potential–independent miniature IPSCs and BDNF did not alter the postsynaptic response to locally applied GABA. These results suggest that BDNF induces the release of a retrograde messenger from the postsynaptic cell that regulates presynaptic neurotransmitter release. Consistent with a role for endocannabinoids as the retrograde signal, the effect of BDNF on IPSCs was blocked by CB1 receptor antagonists and was occluded by a cannabinoid receptor agonist. Furthermore, inhibiting endocannabinoid synthesis or transport also disrupted the BDNF effect, implicating postsynaptic endocannabinoid release triggered by BDNF.