bluuebunny/crossref_metadata_2025 huggingface dataset:
Vascular density is highest in the proximal region of the mouse prostate
Authors: Wang Gui‐Min , Kovalenko Bruce , Wilson E. Lynette , Moscatelli David
Published: April 2007

BACKGROUND

The proximal region of the prostatic ducts harbor the prostatic epithelial stem cells. As stem cell niches in other organs are highly vascularized, we determined if the proximal region is more highly vascularized than the remaining regions of the prostate. The effect of androgen on vascular density in the different prostatic regions was also examined.

METHODS

Sections from prostates were immunostained with antibodies to CD31, and the vascular density in proximal, intermediate, and distal regions was calculated by image analysis software. Vascular density was compared in prostates from castrated mice that received daily inoculations of testosterone or vehicle alone for 3 days. To examine the role of angiogenic factors in the response to androgen, some animals were also treated with soluble VEGF receptor‐2—Fc or Tie‐2—Fc fusion proteins, which inhibit the activities of VEGF and angiopoietins, respectively. The endothelial proliferative response to androgen was determined by double staining sections with antibodies to CD31 and Ki‐67.

RESULTS

In prostates from intact mice, vascular density was highest in the proximal region and lowest in the distal region. Administration of testosterone to castrated mice increased vascular density to the greatest extent in the distal and intermediate regions. The increase in vascular density required VEGF and the angiopoietins. Endothelial cell proliferation was less sensitive to androgen in the proximal region than the remainder of the prostate.

CONCLUSIONS

Vascular density is highest in the proximal region of the prostate, but the proximal vessels are less responsive to testosterone. Prostate 67: 968–975, 2007. © 2007 Wiley‐Liss, Inc.
Late fetal death in offspring and subsequent incidence of prostate cancer in fathers: The Jerusalem Perinatal Study cohort
Authors: Harlap S. , Friedlander Y. , Barchana M. , Calderon R. , Deutsch L. , Kleinhaus K.R. , Perrin M.C. , Tiram E. , Yanetz R. , Paltiel O.
Published: April 2007

BACKGROUND

Little is known of the causes of prostate cancer and few previous studies have investigated men's reproductive histories in relation to this disease. We sought to determine whether risk of prostate cancer was altered in men who had fathered stillborn offspring.

METHODS

We studied the incidence of prostate cancer (N = 252) in a cohort of 15,268 fathers followed for 28–41 years from the birth of a live offspring, whose wives participated in one of two separate surveys of outcomes of previous births. Proportional hazards models were used to estimate relative risks (RR) associated with previous stillbirths, controlling for changes in incidence over time, social and occupational factors.

RESULTS

The 543 men with one or more stillborn offspring experienced an increased risk of prostate cancer (adjusted RR = 1.87, 95% confidence interval = 1.17–3.00, P = 0.0095), compared to men without stillbirths. With one reported stillbirth, the RR was 1.68 (0.99–2.84); with two or more, the RR was 3.29 (1.22–8.88). Results were consistent in men whose wives were interviewed in 1965–1968 and 1974–1976. In 100 fathers with no male offspring and at least one stillbirth the RR was 4.04 (1.87–8.71, P = 0.0004).

CONCLUSIONS

These findings should be considered hypothesis‐generating and require confirmation in other studies. They suggest that stillbirth and prostate cancer may have shared environmental causes; alternatively, genetic susceptibility to prostate cancer might increase the risk of a stillbirth in offspring. Prostate 67: 989–998, 2007. © 2007 Wiley‐Liss, Inc.
Homoepitaxy of ZnO by pulsed‐laser deposition
Authors: von Wenckstern H. , Schmidt H. , Hanisch C. , Brandt M. , Czekalla C. , Benndorf G. , Biehne G. , Rahm A. , Hochmuth H. , Lorenz M. , Grundmann M.
Published: April 2007

ZnO thin films were grown homoepitaxially on O‐face ZnO single crystals by pulsed‐laser deposition. The ZnO substrates grown by the hydrothermal method were heat‐treated in oxygen ambient at 1000 °C for 2 h prior to deposition. After the thermal treatment the substrates show bilayer steps between 200–400 nm wide terraces and a considerably improved crystalline structure. Thin film surfaces exhibit closed loop spirals and show steps of c /2 or c. The FWHM of the (0002) rocking curve of the best sample is 29″. Similar to the substrates used, Al is contained in the thin films (<1014 cm–3) as photoluminescence (PL) and thermal admittance spectroscopy suggest. However, deep levels between 200 and 400 meV below the conduction band are the dominant donors at room temperature. Low temperature PL is dominated by (Al0,X) (I6, FWHM: 200 µeV) and extremely homogeneous (σ ≈ 1%).

magnified image

AFM amplitude error image (scale: 0–10 mV) of homoepitaxial PLD thin film grown at Tg ∼ 650 °C and p = 0.016 mbar. The step height is c (cf. Fig. 1f).

(© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A predicted new type of directional noncovalent interaction
Authors: Murray Jane S. , Lane Pat , Politzer Peter
Published: April 2007

The electrostatic potentials computed on the surfaces of a series of molecules R3X, where X is a Group V atom, show that some of these atoms have regions of positive potential on their outer surfaces, approximately on the extensions of the RX bonds. This suggests the likelihood of weak, directional noncovalent interactions between such atoms and nucleophiles, paralleling what has already been established for Groups VI and VII. The origins and relative strengths of the positive regions are explained in terms of the σ‐hole concept, supported by natural bond orbital analyses. MP2/6‐311++G(3df,2p) calculations confirm the formation of stable complexes between five such Group V molecules and the model nucleophile HCN. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Quantum chemical analysis of reaction paths in chorismate mutase: Conformational effects and electrostatic stabilization
Authors: Szefczyk Borys , Claeyssens Frederik , Mulholland Adrian J. , Sokalski W. Andrzej
Published: April 2007

We have performed a detailed, quantum chemical, decomposition analysis of the physical nature of key interactions in the model enzyme chorismate mutase (CM), for several active conformations produced by high level combined quantum mechanics/molecular mechanics (QM/MM) modeling. In opposition to our previous study, interactions between selected residues in the active site of CM were analysed along the whole reaction path, for several paths. The interaction energy is calculated up to Møller–Plesset second order level of theory and decomposed into physically meaningful components (electrostatic, exchange, delocalization, and electron correlation). This analysis shows, that the dominant interaction is differential stabilization by Arg90: this residue significantly stabilizes the transition state (TS) relative to the substrate in all the paths studied. Interactions in the active site of CM are dominated by the electrostatic component, whereas other components, for example electron correlation, are constant during reaction. Electrostatic effects alone are found to be responsible for lowering the barrier for reaction at the active site. Analysis of four reaction paths derived from QM/MM modeling shows that differences in the height of the barrier are due to differences in the electrostatic interactions of several weakly interacting residues. The influence of conformational effects, such as hydroxyl group rotation in the chorismate/TS, and the distance between Arg90 and the reacting chorismate, have also been analysed. The results show that specific conformations provide better activation barrier lowering. Even small changes in the conformation, like rotation of the hydroxyl group in chorismate (substrate), can significantly alter the activation barrier. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Vision‐aided inertial navigation for pin‐point landing using observations of mapped landmarks
Authors: Trawny Nikolas , Mourikis Anastasios I. , Roumeliotis Stergios I. , Johnson Andrew E. , Montgomery James F.
Published: April 2007

In this paper we describe an extended Kalman filter algorithm for estimating the pose and velocity of a spacecraft during entry, descent, and landing. The proposed estimator combines measurements of rotational velocity and acceleration from an inertial measurement unit (IMU) with observations ofa priorimapped landmarks, such as craters or other visual features, that exist on the surface of a planet. The tight coupling of inertial sensory information with visual cues results in accurate, robust state estimates available at a high bandwidth. The dimensions of the landing uncertainty ellipses achieved by the proposed algorithm are three orders of magnitude smaller than those possible when relying exclusively on IMU integration. Extensive experimental and simulation results are presented, which demonstrate the applicability of the algorithm on real‐world data and analyze the dependence of its accuracy on several system design parameters. © 2007 Wiley Periodicals, Inc.
Athlete: A cargo handling and manipulation robot for the moon
Authors: Wilcox Brian H. , Litwin Todd , Biesiadecki Jeff , Matthews Jaret , Heverly Matt , Morrison Jack , Townsend Julie , Ahmad Norman , Sirota Allen , Cooper Brian
Published: April 2007

A robotic vehicle called ATHLETE—the All‐Terrain Hex‐Limbed, Extra‐Terrestrial Explorer—is described, along with initial results of field tests of two prototype vehicles. This vehicle concept is capable of efficient rolling mobility on moderate terrain and walking mobility on extreme terrain. Each limb has a quick‐disconnect tool adapter so that it can perform general‐purpose handling, assembly, maintenance, and servicing tasks using any or all of the limbs. © 2007 Wiley Periodicals, Inc.
On the size of the algebraic difference of two random Cantor sets
Authors: Dekking Michel , Simon Károly
Published: April 2007

In this paper we consider some families of random Cantor sets on the line and investigate the question whether the condition that the sum of Hausdorff dimension is larger than one implies the existence of interior points in the difference set of two independent copies. We prove that this is the case for the so called Mandelbrot percolation. On the other hand the same is not always true if we apply a slightly more general construction of random Cantor sets. We also present a complete solution for the deterministic case. © 2007 Wiley Periodicals, Inc. Random Struct. Alg., 2008
The game chromatic number of random graphs
Authors: Bohman Tom , Frieze Alan , Sudakov Benny
Published: April 2007

Given a graph G and an integer k, two players take turns coloring the vertices of G one by one using k colors so that neighboring vertices get different colors. The first player wins iff at the end of the game all the vertices of G are colored. The game chromatic number χg(G) is the minimum k for which the first player has a winning strategy. In this study, we analyze the asymptotic behavior of this parameter for a random graph Gn,p. We show that with high probability, the game chromatic number of Gn,p is at least twice its chromatic number but, up to a multiplicative constant, has the same order of magnitude. We also study the game chromatic number of random bipartite graphs. © 2007 Wiley Periodicals, Inc. Random Struct. Alg., 2008
Statistical machine translation using hierarchical phrase alignment
Authors: Watanabe Taro , Imamura Kenji , Sumita Eiichiro , Okuno Hiroshi G.
Published: April 2007

The following three problems are known to exist with statistical machine translation. (1) the modeling problem involved in prescribing translation relations, (2) the problem of determining parameter settings from a text corpus of translations, and (3) the search problem involved in determining the output text (the translation) given a statistical model and an input text. In this paper we find alignments of translations using phrase‐based units in a hierarchical fashion with the intention of solving the above‐mentioned modeling and training problems with such hierarchical phrase alignments. As an initial method we perform chunking on the corpus on the basis of these hierarchical alignments, and create translation models using these chunks as translation units. Then, as a second method we convert the translation relations expressed in the hierarchical phrase alignments into correspondences in the translation model, and perform additional training having initialized the model parameters to values obtained from these relations. The results of experiments with Japanese‐to‐English translation show that both methods improve performance with the second method being particularly effective resulting in an increase in translation rate from 61.3% to 70.0%. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(6): 70–79, 2007; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/scj.20271
A method for evaluating answers by comparing semantic information in a question and answer interaction
Authors: Kunichika Hidenobu , Honda Minoru , Hirashima Tsukasa , Takeuchi Akira
Published: April 2007

In this paper we describe a method for evaluating the validity of answers to questions related to the surface contents of a story in English in order to appropriately ascertain the learner's comprehension state as part of a language learning tool. Since our interactive question and answer tool allows the input of free‐form answers written in natural language, it is necessary to judge the validity of an answer by comparing semantic information in the answer text to that present in the story. As well as identifying discrepancies in these sets of semantic information and checking for the appropriateness of insertions, omissions, and substitutions in the response, our evaluation method attempts to eliminate ambiguities in the natural language processing results. In this paper we also present the results of an investigation into the range of answers to which our response judgment method is applicable as a means of evaluating the method. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(7): 84– 97, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20432
Construction of a remote class support system with humanoid robot
Authors: Toriyama Tomoji , Sakoda Katsuyoshi , Nishihara Isao , Nakano Shizuo
Published: April 2007

Due to advances in network and information terminal device technologies and the development of larger and higher‐resolution display devices, it has become possible to teach classes remotely in a realistic and interactive manner using real‐time video transmission. However, there are times when communication is not sufficient due to constraints imposed by the characteristics of the media used between remote locations, and this is causing problems in presenting the lessons. In this paper, we discuss the results of a study of a method of solving the above problem by using a robot instead of the video image of the teacher, which has conventionally been used as the communication medium between remote locations. By having a humanoid robot in the classroom with the students, a system that allows teaching a class with a manageable extra operational load on the teacher at a remote location was constructed. We showed that the problems with a conventional remote class support system can be solved in a remote class taught using this system. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(6): 21–33, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20472 Copyright © 2004 Wiley Periodicals, Inc.
Navigation of mobile robot using location map of place cells and reinforcement learning
Authors: Tanaka Toshio , Nishida Kenji , Kurita Takio
Published: April 2007

It is known that the hippocampus of rats contains neural cells called “place cells.” Place cells are neural cells that respond selectively when the rat arrives at a particular place. This paper proposes a mobile robot navigation method that uses a place cell position map and reinforcement learning. First, the place cell position map is created by a neural gas using image data and position data from observation points. Next, routes between the place cells are established, and the path to the goal is learned using the actor– critic method, which is a type of reinforcement learning method. Numerical simulations demonstrate that the goal can be reached even if there are motion errors by moving the robot along the route. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(7): 65– 75, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20632
A fast algorithm for mining frequent ordered subtrees
Authors: Hido Shohei , Kawano Hiroyuki
Published: April 2007

In this research, the authors took up the problem of discovering frequent ordered subtree patterns in tree structured data sets, which is of note in the actively researched area of frequent partial structure mining for semistructured data. With conventional algorithms, nonredundant frequent candidate tree enumeration is performed using rightmost expansion, but a problem with that approach is the enumeration of a large number of infrequent candidate trees. Accordingly, the authors propose a right‐and‐left tree join in order for the efficient enumeration of frequent candidate trees, from small‐sized frequent trees to larger frequent candidate trees. Furthermore, the authors constructed AMIOT as an algorithm for discovering frequent ordered subtree patterns using the right‐and‐left tree join for candidate tree enumeration. A performance evaluation using artificial data and XML data indicated that AMIOT was 2.5 to 5 times faster than existing algorithms. © 2007 Wiley Periodicals, Inc. Syst Comp Jpn, 38(7): 34– 43, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20690
Language lateralization in monozygotic twins discordant and concordant for schizophrenia. A functional MRI pilot study
Authors: Spaniel Filip , Tintera Jaroslav , Hajek Tomas , Horacek Jiri , Dezortova Monika , Hajek Milan , Dockery Colleen , Kozeny Jiri , Höschl Cyril
Published: April 2007

Aim

Previous studies have suggested altered structural and functional asymmetry of the brain in schizophrenia.

Methods

Functional MRI was used to assess differences in cortical activation during a verbal task in Broca's area and its contralateral homologue in four pairs of right-handed monozygotic (MZ) twins discordant and concordant for schizophrenia with low and high familial loading for the illness and four healthy control MZ twin pairs.

Results

Pooled data from all subjects with schizophrenia showed increased activation in the right homologue of Broca's area in contrast to healthy individuals. Concordant twins (i.e. high familial loading group) showed prominent between co-twin differences in lateralization index within given region of interest. Intra-pair differences in lateralization index were significantly higher in concordant twins compared to the controls (0.69 ± 0.4 vs. 0.13 ± 0.13, P < 0.03), albeit no significant differences in the variable were shown between the discordant and control groups.

Conclusion

This study provides evidence of reduced cerebral dominance for language processing in patients with schizophrenia. The findings further suggest the need for additional research on relative proportion of genetic and environmental factors underlying deviations of functional asymmetry in schizophrenia.
Kinetic analysis of demetalation of bacteriochlorophyll c and e homologs purified from green sulfur photosynthetic bacteria
Authors: Saga Yoshitaka , Hirai Yuki , Tamiaki Hitoshi
Published: April 2007

Substituent‐dependent demetalation kinetics of natural bacteriochlorophyll (BChl) c and e homologs purified from two green sulfur photosynthetic bacteria was first studied. Separated BChl e homologs, which possessed a formyl group at the 7‐position of their chlorin macrocycles, exhibited a significantly slow removal of central magnesium to free‐base bacteriopheophytins in acidic aqueous acetone compared with the corresponding BChl c homologs, which possessed a methyl group at the 7‐position. Additional methyl groups at the 82‐position of both BChl c and e molecules had little effect on the demetalation kinetics.
A novel light‐ and heat‐responsive regulation of the groE transcription in the absence of HrcA or CIRCE in cyanobacteria
Authors: Kojima Kouji , Nakamoto Hitoshi
Published: April 2007

The inactivation of the hrcA gene resulted in de‐repression of the two CIRCE‐containing groE genes in a cyanobacterium Synechocystis sp. strain PCC6803, indicating that the CIRCE operator/HrcA repressor system operates in the cyanobacterium. We found that the groE expression in the hrcA mutant is greatly induced by heat and/or light. Removal of a K‐box containing and an N‐box containing region upstream of the groESL1 promoter abolished light‐induced transcription of a luxAB reporter gene fused with the groESL1 promoter. Similar sequences to the K‐box, GTTCGG‐NNAN‐CCNNAC, were also found upstream of the dnaK2 genes. A specific binding of a protein(s) to the N‐box, GATCTA, was detected by a gel mobility shift assay with using cell extracts. We propose that the cyanobacterial groEL expression is regulated by a putative positive mechanism mediated by these novel elements in addition to the HrcA/CIRCE system. The groEL2 genes from Synechococcus sp. strain PCC 7942 and Thermosynechococcus elongatus, which lack CIRCE, K‐box, and N‐box naturally, were also induced by heat and/or light, indicating that the control mechanism of the unique light‐responsive groE expression is highly diversified in cyanobacteria.
PRI‐Modeler: Extracting RNA structural elements from PDB files of protein–RNA complexes
Authors: Han Kyungsook , Nepal Chirag
Published: April 2007

A complete understanding of protein and RNA structures and their interactions is important for determining the binding sites in protein–RNA complexes. Computational approaches exist for identifying secondary structural elements in proteins from atomic coordinates. However, similar methods have not been developed for RNA, due in part to the very limited structural data so far available. We have developed a set of algorithms for extracting and visualizing secondary and tertiary structures of RNA and for analyzing protein–RNA complexes. These algorithms have been implemented in a web‐based program called PRI‐Modeler (protein–RNA interaction modeler). Given one or more protein data bank files of protein–RNA complexes, PRI‐Modeler analyzes the conformation of the RNA, calculates the hydrogen bond (H bond) and van der Waals interactions between amino acids and nucleotides, extracts secondary and tertiary RNA structure elements, and identifies the patterns of interactions between the proteins and RNAs. This paper presents PRI‐Modeler and its application to the hydrogen bond and van der Waals interactions in the most representative set of protein–RNA complexes. The analysis reveals several interesting interaction patterns at various levels. The information provided by PRI‐Modeler should prove useful for determining the binding sites in protein–RNA complexes. PRI‐Modeler is accessible at http://wilab.inha.ac.kr/primodeler/, and supplementary materials are available in the analysis results section at http://wilab.inha.ac.kr/primodeler/.
Glucose repression over Saccharomyces cerevisiae glycerol/H+ symporter gene STL1 is overcome by high temperature
Authors: Ferreira Célia , Lucas Cândida
Published: April 2007

High temperature promotes an improved activity of the Saccharomyces cerevisiae glycerol/H+ symporter encoded by STL1, which correlates well with Stl1p levels. This happens in both fermentable and respiratory metabolic growth conditions, though the induction in the latter is much higher. The relief of glucose repression by high temperature at the level of protein expression and activity (Stl1p) is reported for the first time. We reason that the glycerol internal levels fine‐tuning, under heat‐stress as in other physiological condition, can be achieved with the contribution of the tight regulation of the symporter.
Structural characterization of dimeric murine aminoacylase III
Authors: Ryazantsev Sergey , Abuladze Natalia , Newman Debra , Bondar Galyna , Kurtz Ira , Pushkin Alexander
Published: April 2007

Aminoacylase III (AAIII) plays an important role in deacetylation of acetylated amino acids and N‐acetylated S‐cysteine conjugates of halogenated alkenes and alkanes. AAIII, recently cloned from mouse kidney and partially characterized, is a mixture of tetramers and dimers. In the present work, AAIII dimers were purified and shown to be enzymatically active. Limited trypsinolysis showed two domains of ∼9 and 25 kDa. The three‐dimensional structure of the dimer was studied by electron microscopy of negative stained samples and by single‐particle reconstruction. A 16 Å resolution model of the AAIII dimer was created. It has an unusual, cage‐like, structure. A realistic AAIII tetramer model was built from two dimers.
Specificity of αA‐crystallin binding to destabilized mutants of βB1‐crystallin
Authors: Mchaourab Hassane S. , Kumar M. Satish , Koteiche Hanane A.
Published: April 2007

To elucidate the structural and energetic basis of attractive protein interactions in the aging lens, we investigated the binding of destabilized mutants of βB1‐crystallin to the lens chaperones, α‐crystallins. We show that the mutations enhance the binding affinity to αA‐ but not αB‐crystallin at physiological temperatures. Complex formation disrupts the dimer interface of βB1‐crystallin consistent with the binding of a monomer. Binding isotherms obtained at increasing concentrations of βB1‐crystallin deviate from a classic binding equilibrium and display cooperative‐like behavior. In the context of βB1‐crystallin unfolding equilibrium, these characteristics are reflective of the concentration‐dependent change in the population of a dimeric intermediate that has low affinity to αA‐crystallin. In the lens, where α‐crystallin binding sites are not regenerated, this may represent an added mechanism to maintain lens transparency.
Physical activity and cognitive functioning: Translating research to practice with a public health approach
Authors: Prohaska Thomas R. , Peters Karen E.
Published: April 2007

A growing body of research, from retrospective cross‐sectional studies to randomized clinical trials, suggests that physical activity among the elderly has positive effects on a wide range of physiologic systems and tissues, including the cardiovascular, immune, and endocrine systems, and even cognitive functioning. The latter is particularly relevant to the management of Alzheimer's disease and other forms of dementia. There is increasing support that the positive effects of physical activity on cognitive functioning have been obtained at the primary (cognitively healthy older adults), secondary (persons with some loss of cognitive functioning to mild cognitive impairment), and tertiary (older adults with significant cognitive impairment) prevention levels. However, there are several specific components and potential roles for physical activity in the field of cognitive health and functioning that have not been addressed. Moreover, we argue that a population‐based public health perspective is needed as efforts to investigate the physical activity/cognitive health relationship are developed and disseminated for large‐scale implementation. This perspective discusses some of the problems that might be faced when translating basic research findings into public health practice for cognitive impairment and/or dementia in older adults and addresses how some of these problems might be overcome.
Effects of physical activity on cognition, well‐being, and brain: Human interventions
Authors: Kramer Arthur F. , Erickson Kirk I.
Published: April 2007

This article provides a review of the human intervention literature that has examined the influence of fitness training on cognition, well‐being, brain structure, and brain function. Meta‐analyses of this literature, which are reviewed here, suggest robust effects of fitness training on cognition and well‐being. Although there are currently few human intervention studies that have examined fitness effects on human brain function and structure, the studies that have been conducted report promising results.
Inter‐organizational communication as a relational competency: Antecedents and performance outcomes in collaborative buyer–supplier relationships
Authors: Paulraj Antony , Lado Augustine A. , Chen Injazz J.
Published: April 2007

Inter‐organizational communication has been documented as a critical factor in promoting strategic collaboration among firms. In this paper, we seek to extend the stream of research in supply chain management by systematically investigating the antecedents and performance outcomes of inter‐organizational communication. Specifically, inter‐organizational communication is proposed as arelational competencythat may yield strategic advantages for supply chain partners. Using structural equation modeling, we empirically test a number of hypothesized relationships based on a sample of over 200 United States firms. Our results provide strong support for the notion of inter‐organizational communication as a relational competency that enhances buyers’ and suppliers’ performance. Implications for future research and practice are offered.
The ten commandments—or how the therapist can avoid delinquency
Authors: Berry Rowland
Published: April 2007

The author has been treating delinquent girls in a closed borstal for 12 years. From this experience he has derived certain rules of therapeutic behaviour which he expresses as the Ten Commandments. The Commandments are guide‐lines enabling the therapist to avoid behaviour which if the patient sees as false, will negate therapeutic efforts. In addition, having interviewed some 3000 borstal trainees, and treated a large proportion of these, the author makes some observations about unsatisfied dependency needs, the satisfaction of which is seen as a priority in residential treatment.
The adolescent and his parents: the parental crisis
Authors: Braconnier A. , Marcelli D.
Published: April 2007

We are concerned in this article with the reaction of parents to adolescents in crisis. This may be sufficient to create a parental crisis in response.

The psychodynamics of the process of adolescence have been described by many analysists. We note and illustrate psychodynamic factors in the parents of adolescents: possible incest, mourning over lost controls (a work of mourning in line with that of their adolescents), and a revival of the frustrations of their own youth.

Inadequate organisation of these factors by the parents can aggravate their adolescent's crisis. This leads us to include the parents as often as possible in the management of adolescents, both in the assessment and in our therapeutic endeavours.
Parent‐child role reversal and adolescent suicidal behaviour
Authors: Kerfoot Michael
Published: April 2007

This paper examines the concept of role reversal in relation to disordered parent‐child relationships. By the use of role analysis, the dynamics of role reversal are revealed and using original case material the author demonstrates how suicidal behaviour may be the ultimate response by the adolescent to the stress of being persistently cast in the “parent” role. Treatment methods focussing on the dysfunctional relationship are briefly described.
Binocular vision-based 3-D trajectory following for autonomous robotic manipulation
Authors: Chang Wen-Chung
Published: April 2007

Robotic manipulators that have interacted with uncalibrated environments typically have limited positioning and tracking capabilities, if control tasks cannot be appropriately encoded using available features in the environments. Specifically, to perform 3-D trajectory following operations employing binocular vision, it seems necessary to have a priori knowledge on pointwise correspondence information between two image planes. However, such an assumption cannot be made for any smooth 3-D trajectories. This paper describes how one might enhance autonomous robotic manipulation for 3-D trajectory following tasks using eye-to-hand binocular visual servoing. Based on a novel encoded error, an image-based feedback control law is proposed without assuming pointwise binocular correspondence information. The proposed control approach can guarantee task precision by employing only an approximately calibrated binocular vision system. The goal of the autonomous task is to drive a tool mounted on the end-effector of the robotic manipulator to follow a visually determined smooth 3-D target trajectory in desired speed with precision. The proposed control architecture is suitable for applications that require precise 3-D positioning and tracking in unknown environments. Our approach is successfully validated in a real task environment by performing experiments with an industrial robotic manipulator.
Charakteristika des Virtual Reality-Mediums als Determinanten der intermodalen Informationsintegration in einer hybriden Realität
Authors: Heineken Edgar , Schulte Frank P.
Published: April 2007

Zusammenfassung. In einer hybriden Realität kann Information aus der virtuellen Realität (VR) und Information aus der natürlichen Realität umso leichter integriert werden, je stärker das VR-Medium Präsenz erzeugt, d.h. je mehr es gestattet, Information aus der virtuellen Realität als ebenso ‘unvermittelt‘ zu erleben wie Information aus der natürlichen Realität. Zur Untersuchung dieses Zusammenhanges wird die Größengewichtstäuschung (GGT) herangezogen, wonach von zwei gleich schweren aber unterschiedlich großen Objekten das kleinere Objekt als schwerer beurteilt wird. Es wird erwartet, dass die Täuschung in einer hybriden Realität, in der die Versuchsteilnehmer/innen die Objekte in der VR sehen und gleichzeitig in der natürlichen Realität heben, umso größer ist, je mehr das VR-Medium für das Präsenz-Erleben relevante Bedingungen wie Abschirmung und sensorisches Feedback erfüllt. 60 Versuchsteilnehmer/innen beurteilten das Gewicht von insgesamt 15 unterschiedlich hohen und schweren Zylindern (drei Höhen, fünf Gewichte) nach der Größenverhältnisschätzmethode. Sie sahen die gehobenen Zylinder entweder in der natürlichen Realität, in einer von drei unterschiedlichen Head-Mounted-Display (HMD) Virtual Realities (mit unverzögerter Synchronisation von Bild und Kopfbewegung, mit verzögerter Synchronisation von Bild und Kopfbewegung, ohne Synchronisation von Bild und Kopfbewegung) oder in zwei unterschiedlichen Desktop-Virtual Realities (mit Abschirmung von visuellen Reizen aus der natürlichen Realität, ohne Abschirmung). Die psychophysischen Urteile zeigen, dass der Grad der GGT, quantifiziert durch den negativen Steigungskoeffizienten der linearen Abhängigkeit der Gewichtsurteile von der Höhe der Zylinder, in der HMD-Realität mit unverzögerter Synchronisation am höchsten ist. Die GGT wird als Verfahren zur Operationalisierung von Präsenz diskutiert.
Suspended sediment transport in an ephemeral stream following wildfire
Authors: Malmon Daniel V. , Reneau Steven L. , Katzman Danny , Lavine Alexis , Lyman Jared
Published: April 2007

We examine the impacts of a stand‐clearing wildfire on the characteristics and magnitude of suspended sediment transport in ephemeral streams draining the burn area. We report the results of a monitoring program that includes 2 years of data prior to the Cerro Grande fire in New Mexico, and 3 years of postfire data. Suspended sediment concentration (SSC) increased by about 2 orders of magnitude following the fire, and the proportion of silt and clay increased from 50% to 80%. For a given flow event, SSC is highest at the flood bore and decreases monotonically with time, a pattern evident in every flood sampled both before and after the fire. We propose that the accumulation of flow and wash load at the flow front is an inherent characteristic of ephemeral stream flows, due to amplified momentum losses at the flood bore. We present a new model for computing suspended sediment transport in ephemeral streams (in the presence or absence of wildfire) by relating SSC to the time following the arrival of the flood bore, rather than to instantaneous discharge. Using this model and a rainfall history, we estimate that in the 3 years following the fire, floods transported in suspension a mass equivalent to about 3 mm of landscape lowering across the burn area, 20% of this following a single rainstorm. We test the model by computing fine sediment delivery to a small reservoir in an adjacent watershed, where we have a detailed record of postfire sedimentation based on repeat surveys. Systematic discrepancies between modeled and measured sedimentation rates in the reservoir suggest rapid reductions in suspended sediment delivery in the first several years after the fire.
Falling atmospheric pressure as a trigger for methane ebullition from peatland
Authors: Tokida T. , Miyazaki T. , Mizoguchi M. , Nagata O. , Takakai F. , Kagemoto A. , Hatano R.
Published: April 2007

Peatlands are widely regarded as a significant source of atmospheric CH4, a potent greenhouse gas. At present, most of the information on environmental emissions of CH4 comes from infrequent, temporally discontinuous ground‐based flux measurements. Enormous efforts have been made to extrapolate measured emission rates to establish seasonal or annual averages using relevant biogeochemical factors, such as water table positions or peat temperatures, by assuming that the flux was stationary during a substantial nonsampling period. However, this assumption has not been explicitly verified, and little is known about the continuous variation of the CH4 flux in a timescale of individual flux measurement. In this study, we show an abrupt change in the CH4 emission rate associated with falling atmospheric pressure. We found that the CH4 flux can change by 2 orders of magnitude within a matter of tens of minutes owing to the release of free‐phase CH4 triggered by a drop in air pressure. The contribution of the ebullition to the total CH4 flux during the measurements was significant (50–64%). These results clearly indicated that field campaigns must be designed to cover this rapid temporal variability caused by ebullition, which may be especially important in intemperate weather. Process‐based CH4 emission models should also be modified to include air pressure as a key factor for the control of ebullient CH4 release from peatland.
Possible persistent ionization caused by giant blue jets
Authors: Lehtinen Nikolai G. , Inan Umran S.
Published: April 2007

We consider the possible production of persistent ionization at low altitudes (h ≤ 70 km) by giant blue jets (GBJ), using a new five constituent model of stratospheric/lower‐ionospheric chemistry. Results indicate substantial ionization at h < 50 km, which exhibits an initially rapid (few seconds) recovery due to electron attachment, followed by a long enduring recovery (>10 minutes) determined by the time scale of mutual neutralization of negative and positive ions. Such recovery signatures may be observable in subionospheric VLF data in the form of Early/fast events with long lasting recoveries. Analysis also indicates that electrons may sometimes be quickly (≲1 ms) removed by the dissociative attachment mechanism in the presence of a high electric field, while the negative and positive ions remain and persist for extended periods of time. In such cases, the initial rapid recovery may not be observable in VLF data due to its typical time resolution of ∼10 to 20 ms. In stratosphere (h ≲ 50 km) the ionization recovery is found to not be accurately described by a four‐constituent model proposed by Glukhov et al., (1992), hereinafter referred to as GPI, necessitating a fifth constituent, namely the heavy negative ions with high electron affinity (Nx−).
Understanding storm‐time ring current development through data‐model comparisons of a moderate storm
Authors: Zhang Jichun , Liemohn Michael W. , De Zeeuw Darren L. , Borovsky Joseph E. , Ridley Aaron J. , Toth Gabor , Sazykin Stanislav , Thomsen Michelle F. , Kozyra Janet U. , Gombosi Tamas I. , Wolf Richard A.
Published: April 2007

With three components, global magnetosphere (GM), inner magnetosphere (IM), and ionospheric electrodynamics (IE), in the Space Weather Modeling Framework (SWMF), the moderate storm on 19 May 2002 is globally simulated over a 24‐hour period that includes the sudden storm commencement (SSC), initial phase, and main phase of the storm. Simulation results are validated by comparison with in situ observations from Geotail, GOES 8, GOES 10, Polar, LANL MPA, and the Sym‐H and Dst indices. It is shown that the SWMF is reaching a sophistication level for allowing quantitative comparison with the observations. Major storm characteristics at the SSC, in the initial phase, and in the main phase are successfully reproduced. The simulated plasma parameters exhibit obvious dawn‐dusk asymmetries or symmetries in the ring current region: higher density near the dawn and higher temperature in the afternoon and premidnight sectors; the pressure is highest on the nightside and exhibits a near dawn‐dusk symmetry. In addition, it is found in this global modeling that the upstream solar wind/IMF conditions control the storm activity and an important plasma source of the ring current is in the solar wind. However, the ionospheric outflow can also affect the ring current development, especially in the main phase. Activity in the high‐latitude ionosphere is also produced reasonably well. However, the modeled cross polar cap potential drop (CPCP) in the Southern Hemisphere is almost always significantly larger than that in the Northern Hemisphere during the May storm.
Modeling the transport and optical properties of smoke aerosols from African savanna fires during the Southern African Regional Science Initiative campaign (SAFARI 2000)
Authors: Matichuk R. I. , Colarco P. R. , Smith J. A. , Toon O. B.
Published: April 2007

We investigate the transport and optical properties of smoke aerosols from southern Africa using an offline three‐dimensional aerosol transport model. We use Sun photometer retrieved particle size distributions and monthly mean satellite‐derived smoke emissions as input parameters. We find that using these observations in our model allows us to reproduce the measured optical properties collected during the Southern African Regional Science Initiative campaign (SAFARI 2000). In particular, we find day‐to‐day oscillations in the simulated aerosol optical thickness (AOT) similar to Aerosol Robotic Network (AERONET) retrievals, suggesting that variations in aerosol loading are controlled more by transport processes than fluctuations in smoke emissions. We also find that the simulated AOT, Ångström exponent, and single scattering albedo compare well to AERONET. The model and satellite observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Multiangle Imaging Spectroradiometer (MISR) also show that the dominant transport of smoke plumes over Africa was westward during September 2000. However, the satellite observations show higher AOT values than our model over the Atlantic Ocean. These higher values observed by the satellites may be a result of poor single scattering assumptions and the contamination by subpixel clouds in the retrievals. However, the monthly mean smoke emissions may also be too low, resulting in low simulated AOT values. We also find discrepancies between MODIS and MISR, which limit our ability to use the satellite data to validate our model. Our work suggests strategies for improving the treatment of smoke aerosols from African biomass burning in climate and microphysical models.
Time evolution of artificial electron heating in polar mesosphere summer echo layers
Authors: Havnes O. , Kassa M. , La Hoz C.
Published: April 2007

Artificial electron heating by the use of high‐energy transmitters can have a strong effect on the observed strength of the radar polar mesospheric summer echoes (PMSE). This heating can make PMSE go through a sequence where it nearly disappears as the heater is turned on and can also cause PMSE to overshoot its preheating strength by a large factor as the heater is switched off. Modeling the effect of heating on the PMSE scattering has shown that the form of the variation in PMSE intensity during the heater cycling is crucially dependent on the amount of electron heating and on the dust and plasma conditions. In the present paper we examine if and when the model assumption that the electron temperature Te stays constant during the heating after the first sudden rise when the heater is switched on is correct. We find that this is valid for low values of the ratio between the charge density of dust and electron charge density throughout the PMSE layer since dust has little effect on the electron density. However, when this ratio is not small compared to 1, so we have an electron bite‐out, the increased electron temperature and collision rate of electrons and dust particles can now lead to a significant reduction in the electron density. This will lead to a reduction in the absorption of heater wave energy in the bite‐out, and more wave energy will become available in its upper parts and in the PMSE above it where the electron temperature now will increase. This situation does, however, require that a substantial fraction of the heater wave energy reach the PMSE layer so that at least the lower parts of it are strongly heated.
Olympus Mons, Mars: Inferred changes in late Amazonian aged effusive activity from lava flow mapping of Mars Express High Resolution Stereo Camera data
Authors: Bleacher Jacob E. , Greeley Ronald , Williams David A. , Werner Stephanie C. , Hauber Ernst , Neukum Gerhard
Published: April 2007

Lava flow mapping was conducted on a north‐south transect of Olympus Mons using the European Space Agency's Mars Express High Resolution Stereo Camera (HRSC) image H0037. The HRSC image was coregistered to Mars Orbiter Laser Altimeter, Thermal Emission Imaging System, and Mars Orbiter Camera data, enabling lava flow structures to be differentiated and mapped consistently across the shield. Because different structures develop as a result of different effusive conditions, their abundance and distribution provide insight into the eruptive history of a shield volcano. Results show that lava channels are the dominant flow structure, whereas tabular sheets are most common beyond the basal scarp. A hummocky unit dominates the summit area and likely represents a combination of (1) volcanic lava flows, (2) pyroclastic deposits, (3) a dust mantle, and (4) frozen volatiles, all of which have been suggested to exist on Olympus Mons in the past. Lava fans are typically associated with lava tubes, indicating that they represent tube outbreaks as was previously suggested as one possible formation mechanism. No vents were identified, suggesting that major rift zones have not developed on the north or south flank. Younger channel‐fed flows typically embay older tube‐related flows, which they outnumber by a ratio of 5:1. Therefore Olympus Mons likely experienced a change in eruptive style from longer‐lived, stable, tube‐forming eruptions to shorter‐lived, less stable, channel‐forming eruptions in the late Amazonian. A similar trend exists for the Hawaiian volcanoes in which a decrease in the magma production rate drives a change to dominantly channel forming eruptions associated with increased shield age.