bluuebunny/crossref_metadata_2025 huggingface dataset:
A queueing system with multiple service time distributions
Authors: Harris Carl M.
Published: May 2007

This paper explores a modification of the output discipline for the Poisson input, exponential output, single channel, first‐come, first‐served queueing system. Instead, the service time distribution of customers beginning service when alone in the system is considered different from that governing service times of all other customers. More specifically, the service times of lone customers are governed by a one parameter gamma distribution, while the service times of all other customers are exponentially ajstributed. The generating function for the steady‐state probsbilities, nj = Pr { j customers in system at an arbitrary point of departure}, of the imbedded chain, {Xn/Xn = number in system after nth customer is serviced}, is obtained, and the steady‐state probabilities, themselves, are found in closed form.
Bounds on parallel‐processing of queues with multiple‐phase jobs
Authors: Coffman E. G.
Published: May 2007

Currently, both the hardware and software designs of many large computing systems aim at improved system performance through exploitation of parallelism in multiprocessor systems. In studying these systems, mathematical modelling and analysis constitute an important step towards providing design tools that can be used in building such systems. With this view the present paper describes a queueing model of a multiprocessor system operating in a job‐shop environment in which arriving jobs consist of a random number of segments (sub‐jobs). Two service disciplines are considered: one assumes that the sub‐jobs of a given job are capable of parallel operation on different processors while the other assumes that the same sub‐jobs must be operated in a strictly serial sequ'snce. The results (in particular, the mean number in the system and waiting time in queue) obtained for these two disciplines are shown to be bounds for more general job structures.
Congestion analysis of a computer core storage system
Authors: Chang W.
Published: May 2007

This paper studies the congestion problems of the computer core storage units. The principle of storage request interleaving is briefly discussed as means of increasing thruput. An analytic model is proposed to analyze the core storage system with a two‐way interleaving feature. The model, an approximation to the physical system, is an extension of a queueing model with bulk service considered by Bailey in Ref. [1].
The many‐product cargo loading problem
Authors: Pruzan Peter Mark , Jackson J. T. Ross
Published: May 2007

An algorithm, based upon dynamic programming, is developed for a class of fixed‐cost cargo loading problems. The problems can be formulated as integer programming problems, but cannot be efficiently solved as such because of computational difficulties. The algorithm developed has proved to be very efficient in an actual operations research study involving over 500 different cargo items, more than 40 possible stops and several types of transportation vehicles. A numerical illustration is provided.
Optimal scheduling of objects in circulating systems
Authors: Wridman Donald R.
Published: May 2007

A “circulating system” is a finite collection of objects, each of which is oscillaling between two states. The prototype system is that of ships on patrcl,each subject to a quasi‐regular “duty‐service” cycle. There are various restrictions on the time spent in either state by an object and on the number of objects in a state at any one time. Schedules are sought in which the total number in one state is as large and as constant as possible. The maximal average number in one state is calculated, and a necessary and sufficient condition is given for a schedule to achieve it. Procedures are developed for constructing a schedule which achieves the maximal average in the most constant manner.
More ado about economic order quantities (EOQ)
Authors: Presutti Victor J. , Trepp Richard C.
Published: May 2007

This paper is concerned with the determination of explicit expressions for economic order quantities and reorder levels, such that the cost of ordering and holding inventory is minimized for specific backorder constraints. Holding costs are applied either to inventory position or on‐hand inventory, and the backorder constraint is considered in terms of the total number of backorders per year or the average number of backorders at any point in time. Through the substitution of a new probability density function in place of the normal p.d.f., explicit expressions are determined for the economic order quantities and the reorder points. The resulting economic order quantities are independent of all backorder constraints. It is also concluded that under certain conditions, the minimization of ordering costs and inventory holding costs (applied to inventory position), subject to a backorder constraint, is equivalent in terms of reorder levels to minimization of the safety level dollar investment subject to the same backorder constraint.
The relationship between decision variables and penalty cost parameter in (Q, R) inventory models
Authors: Kaplan Alan J.
Published: May 2007

This paper is concerned with the optimum decision variables found using order quantity, reorder point (Q, R) inventory models. It examines whether the optimum variables (Q* and R*) are necessarily monotonic functions of the backorder cost parameter (or equivalently of the performance objective). For a general class of models it is proved that R* must increase as the performance objective is raised, and an inequality condition is derived which governs how Q* will change. Probability distributions of lead time demand are cited or found for which Q* increases, Q* decreases, and Q* is independent of increases in performance objectives or backorder cost parameter.
Getting things started
Authors: Gardiner Frederick G.
Published: May 2007

Toronto metropolitan area, with 13 communities, made no progress until planned as a single unit.
How cities may grow
Authors: Nixon John H.
Published: May 2007

Efforts of urban areas to meet local economic problems play vital role in national program.
Working for freedom
Authors: Reichler Oxie
Published: May 2007

The spirit of liberty leads torch‐bearing men, women to give of themselves in public service.
The states must plan
Authors: Martin James W.
Published: May 2007

Tragic failures in past seen showing need to provide intelligently for growth, change.
Power of rural vote
Authors: Eisenberg Ralph
Published: May 2007

Reapportionments made after 1960 census show little improvement in strength of urban areas.
Simple finite element‐based computation of distance functions in unstructured grids
Authors: Elias Renato N. , Martins Marcos A. D. , Coutinho Alvaro L. G. A.
Published: May 2007

A distance field is a representation of the closest distance from a point to a given surface. Distance fields are widely used in applications ranging from computer vision, physics and computer graphics and have been the subject of research of many authors in the last decade. Most of the methods for computing distance fields are devoted to Cartesian grids while little attention has been paid to unstructured grids. Finite element methods are well known for their ability to deal with partial differential equations in unstructured grids. Therefore, we propose an extension of the fast marching method for computing a distance field in a finite element context employing the element interpolation to hold the Eikonal property (∥∇φ∥ = 1). A simple algorithm to develop the computations is also presented and its efficiency demonstrated through various unstructured grid examples. We observed that the presented algorithm has processing times proportional to the number of mesh nodes. Copyright © 2007 John Wiley & Sons, Ltd.
Hydrophobic guar gum derivatives prepared by controlled grafting processes
Authors: Bahamdan Ahmad , Daly William H.
Published: May 2007

Introduction of polyalkoxyalkyleneamide grafts to guar gum produces a new water soluble guar derivative. Modification of either guar gum or hydroxyopropyl guar is achieved in a three‐step process: carboxymethylation with sodium chloroacetate, esterification with dimethyl sulfate (DMS) and amidation with a series of polyalkoxyalkyleneamines. The process was followed using infrared spectroscopy; the grafted guar derivatives were characterized using 1H NMR. A series of hydroxypropyl guar (HPR) derivatives with degrees of carboxymethylations ranging from 0.2–0.3 were modified with polyalkoxyalkyleneamines with molecular weights ranging from 300 to 3000. The ratio of oxypropylene to oxoethylene units in the polyalkoxyalkyleneamines was varied from 9/1 to 8/58 to adjust the hydrophobicity of the grafts. Aqueous solutions of the graft copolymers exhibit viscosities one to two orders of magnitude lower than the corresponding solutions of the parent guar gum. Copyright © 2007 John Wiley & Sons, Ltd.
Hydrophobic guar gum derivatives prepared by controlled grafting processes–Part II: rheological and degradation properties toward fracturing fluids applications
Authors: Bahamdan Ahmad , Daly William H.
Published: May 2007

Introduction of polyalkoxyalkyleneamide grafts to guar gum produces new water soluble guar derivatives as described in an earlier publication.10 In this paper, the rhelogical behavior of these products was explored in more detail at 25 and 65°C. In addition, the viscosity was measured at high temperatures (90 and 120°C) and pressure (150 psi) to partially simulate the down hole conditions of oil wells. Upon treatment with zirconium lactate, the cross‐linked hydrophobically‐modified CMG derivatives exhibited better high‐temperature stability and higher gel viscosities than the corresponding CMHPG derivatives. The cross‐linked gel viscosities indicate that gels will be capable of supporting a high proppant carrying capacity. To facilitate removal of the gels from the formation, the hydrophobically modified derivatives were treated with an enzyme breaker system which produced fragments capable of producing stable emulsions when extracted with toluene. Thus, the clean up process will be enhanced by emulsification of the gel fragments produced by the gel hydrolysis. The low viscosities of the linear derivatives, the rapid formation of high viscosity gels upon cross‐linking and generation of emulsifiers during the gel removal suggest that these new derivatives are good candidates for fracturing fluid applications. Copyright © 2007 John Wiley & Sons, Ltd.
On the testing, characterization, and evaluation of PV inverters and dynamic MPPT performance under real varying operating conditions
Authors: Sanchis Pablo , López Jesús , Ursúa Alfredo , Gubía Eugenio , Marroyo Luis
Published: May 2007

The increasing number of photovoltaic inverters that are coming on to the PV market stresses the need to carry out a dynamic characterization of these elements and their maximum power point tracking (MPPT) algorithms under real operating conditions. In order to make these conditions repeatable at the laboratory, PV array simulators are used. However, actual simulators, including the commercial simulators, recreate only a single or small set of PV array characteristic curves in which quite commonly theoretical calculations are included in order to simulate irradiance and temperature artificial variations. This is far from being a recreation of the real and long dynamic behavior of a PV array or generator. The testing and evaluation of the performance of PV inverters and MPPT algorithms has to be carried out when the PV system moves dynamically according to real operating conditions, including processes such as rapidly changing atmospheric conditions, partial shadows, dawn, and nightfall. This paper tries to contribute to the analysis of this problem by means of an electronic system that both measures the real evolution of the characteristic curves of PV arrays at outdoor operation and then recreates them at the laboratory to test PV inverters. This way the equipment can highlight the different performances of PV inverters and MPPT techniques when they operate under real operating conditions. As an example, two commercial inverters are tested and analyzed under the recreated behavior of a PV generator during 2 singular days that include processes of partial shading and fast irradiance variations. Copyright © 2007 John Wiley & Sons, Ltd.
8% Efficient thin‐film polycrystalline‐silicon solar cells based on aluminum‐ induced crystallization and thermal CVD
Authors: Gordon I. , Carnel L. , Van Gestel D. , Beaucarne G. , Poortmans J.
Published: May 2007

A considerable cost reduction could be achieved in photovoltaics if efficient solar cells could be made from polycrystalline‐silicon (pc‐Si) thin films on inexpensive substrates. We recently showed promising solar cell results using pc‐Si layers obtained by aluminum‐induced crystallization (AIC) of amorphous silicon in combination with thermal chemical vapor deposition (CVD). To obtain highly efficient pc‐Si solar cells, however, the material quality has to be optimized and cell processes different from those applied for standard bulk‐Si solar cells have to be developed. In this work, we present the different process steps that we recently developed to enhance the efficiency of pc‐Si solar cells on alumina substrates made by AIC in combination with thermal CVD. Our present pc‐Si solar cell process yields cells in substrate configuration with efficiencies so far of up to 8·0%. Spin‐on oxides are used to smoothen the alumina substrate surface to enhance the electronic quality of the absorber layers. The cells have heterojunction emitters consisting of thin a‐Si layers that yield much higherVocvalues than classical diffused emitters. Base and emitter contacts are on top of the cell in interdigitated finger patterns, leading to fill factors above 70%. The front surface of the cells is plasma textured to increase the current density. Our present pc‐Si solar cell efficiency of 8% together with the fast progression that we have made over the last few years indicate the large potential of pc‐Si solar cells based on the AIC seed layer approach. Copyright © 2007 John Wiley & Sons, Ltd.
Voltage dependent photocurrent collection in CdTe/CdS solar cells
Authors: Hegedus Steven , Desai Darshini , Thompson Chris
Published: May 2007

The voltage dependence of the photocurrent JL(V) of CdTe/CdS solar cells has been characterized by separating the forward current from the photocurrent at several illumination intensities. JL(V) reduces the fill factor (FF) of typical cells by 10–15 points, the open circuit voltage (VOC) by 20–50 mV, and the efficiency by 2–4 points. Eliminating the effect of JL(V) establishes superposition between light and dark J(V) curves for some cells. Two models for voltage dependent collection give reasonable fits to the data: (1) a single carrier Hecht model developed for drift collection in p‐i‐n solar cells in which fitting yields a parameter consistent with lifetimes of 10−9 s as measured by others; or (2) the standard depletion region and bulk diffusion length model fits almost as well. The simple Hecht‐like drift collection model for photocurrent gives very good agreement to J(V) curves measured under AM1·5 light on CdTe/CdS solar cells with FF from 53% to 70%, CdTe thickness from 1·8 to 7·0 µm, in initial and stressed states. Accelerated thermal and bias stressing increases JL(V) losses as does insufficient Cu. This method provides a new metric for tracking device performance, characterizes transport in the high field depletion region, and quantifies a significant FF loss in CdTe solar cells. Copyright © 2007 John Wiley & Sons, Ltd.
Theory and experiments on the back side reflectance of silicon wafer solar cells
Authors: Kray Daniel , Hermle Martin , Glunz Stefan W.
Published: May 2007

New passivation layers for the back side of silicon solar cells have to show high performance in terms of electrical passivation as well as high internal reflectivity. This optical performance is often shown as values for the back side reflectance Rb which describes the rear internal reflection. In this paper, we investigate in detail the meaning of this single‐value parameter, its correct determination and the use in one‐dimensional simulations with PC1D. The free‐carrier‐absorption (FCA) as non‐carrier‐generating absorption channel is analyzed for solar cells with varying thickness. We apply the optical analysis to samples with different thickness, silicon oxide layer thickness, rear side topography as well as passivation layers (SiO2, SiNx, SiC and stack systems). Additionally, the optical influence of the laser‐fired contacts (LFC) process is experimentally investigated. Finally, we show that with correct parameters, the one‐dimensional simulation of very thin silicon solar cells can successfully be performed. Copyright © 2007 John Wiley & Sons, Ltd.
Natural products that have been used commercially as crop protection agents
Authors: Copping Leonard G , Duke Stephen O
Published: May 2007

Many compounds derived from living organisms have found a use in crop protection. These compounds have formed the basis of chemical synthesis programmes to derive new chemical products; they have been used to identify new biochemical modes of action that can be exploited by industry‐led discovery programmes; some have been used as starting materials for semi‐synthetic derivatives; and many have been used or continue to be used directly as crop protection agents. This review examines only those compounds derived from living organisms that are currently used as pesticides. Plant growth regulators and semiochemicals have been excluded from the review, as have living organisms that exert their effects by the production of biologically active secondary metabolites. Copyright © 2007 Society of Chemical Industry
Development of a potent and selective GPR7 (NPBW1) agonist: a systematic structure–activity study of neuropeptide B
Authors: Kanesaka Maki , Matsuda Masao , Hirano Atsushi , Tanaka Kenichi , Kanatani Akio , Tokita Shigeru
Published: May 2007

Neuropeptide B (NPB) has been recently identified as an endogenous ligand for GPR7 (NPBW1) and GPR8 (NPBW2) and has been shown to possess a relatively high selectivity for GPR7. In order to identify useful experimental tools to address physiological roles of GPR7, we synthesized a series of NPB analogs based on modification of an unbrominated form of 23 amino acids with amidated C‐terminal, Br(−)NPB‐23‐NH2. We confirmed that truncation of the N‐terminal Trp residue resulted in almost complete loss of the binding affinity of NPB for GPR7 and GPR8, supporting the special importance of this residue for binding. Br(−)NPB‐23‐NH2 analogs in which each amino acid in positions 4, 5, 7, 8, 9, 10, 12 and 21 was replaced with alanine or glycine exhibited potent binding affinity comparable to the parent peptide. In contrast, replacement of Tyr11 with alanine reduced the binding affinity for both GPR7 and GPR8 four fold. Of particular interest, several NPB analogs in which the consecutive amino acids from Pro4 to Val13 were replaced with several units of 5‐aminovaleric acid (Ava) linkers retained their potent affinity for GPR7. Furthermore, these Ava‐substituted NPB analogs exhibited potent agonistic activities for GPR7 expressed in HEK293 cells. Among the Ava‐substituted NPB analogs, analog 15 (Ava‐5) and 17 (Ava‐3) exhibited potency comparable to the parent peptide for GPR7 with significantly reduced activity for GPR8, resulting in high selectivity for GPR7. These highly potent and selective NPB analogs may be useful pharmacological tools to investigate the physiological and pharmacological roles of GPR7. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd.
Characterization of the branched antimicrobial peptide M6 by analyzing its mechanism of action and in vivo toxicity
Authors: Pini Alessandro , Giuliani Andrea , Falciani Chiara , Fabbrini Monica , Pileri Silvia , Lelli Barbara , Bracci Luisa
Published: May 2007

We analyzed functional activity of the antimicrobial peptide M6 in vitro and in vivo. The peptide was identified by our group by phage library selection, rational modification and synthesis in a tetrabranched form (Pini et al., Antimicrob. Agents Chemother. 2005; 49: 2665–72). We found that it binds lipopolysaccharide, causes perforation of cell membranes without destroying external cell morphology and strongly binds DNA. The latter feature suggests that it could inhibit metabolic pathways, blocking DNA replication and/or transcription. We also observed that M6 does not stimulate humoral immune response when repeatedly administered to animals. We also analyzed M6 toxicity when administered to animals by intraperitoneal or by intravenous injection, determining a preliminary LD50 (125 and 37.5 mg/kg, respectively), which suggested that M6 could be used in vivo. These features make the antimicrobial branched peptide M6 a promising candidate for the development of a new antibacterial drug. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd.
Conformation–activity relationship of peptide T and new pseudocyclic hexapeptide analogs
Authors: D'ursi Annamaria , Caliendo Giuseppe , Perissutti Elisa , Santagada Vincenzo , Severino Beatrice , Albrizio Stefania , Bifulco Giuseppe , Spisani Susanna , Temussi Piero A.
Published: May 2007

Peptide T (ASTTTNYT), a segment corresponding to residues 185–192 of gp120, the coat protein of HIV, has several important biological properties in vitro that have stimulated the search for simpler and possibly more active analogs. We have previously shown that pseudocyclic hexapeptide analogs containing the central residues of peptide T retain considerable chemotactic activity. We have now extended the design of this type of analogs to peptides containing different aromatic residues and/or Ser in lieu of Thr. The complex conformation‐activity relationship of these analogs called for a reexamination of the basic conformational tendencies of peptide T itself. Here, we present an exhaustive NMR conformational study of peptide T in different media. Peptide T assumes a γ‐turn in aqueous mixtures of ethylene glycol, a type‐IV β‐turn conformation in aqueous mixtures of DMF, and a type‐II β‐turn conformation in aqueous mixtures of DMSO. The preferred conformations for the analogs were derived from modeling, starting from the preferred conformations of peptide T. The best models derived from the γ‐turn conformation of peptide T are those of peptides XII (DSNYSR), XIII (ETNYTK) and XVI (ESNYSR). The best models derived from the type‐IV β‐turn conformation of peptide T are those of peptides XIV (KTTNYE) and XV (DSSNYR). No low‐energy models could be derived starting from the type‐II β‐turn conformation of peptide T. The analogs with the most favored conformations are also the most active in the chemotactic test. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd.
Prophylactic effect of flaxseed oil against radiation‐induced hepatotoxicity in mice
Authors: Bhatia A. L. , Sharma Avadhesh , Patni Shikha , Sharma Antim Lata
Published: May 2007

Flaxseed (linseed, Linum usitatissimum, Linaceae) is widely used for its edible oil in many parts of the world. The present study investigates the radioprotective and antioxidative potential of flaxseed oil (FO). Swiss albino mice were administered FO orally once daily for 15 consecutive days, then exposed to a single dose of 5 Gy of gamma radiation. Lipid peroxide, reduced glutathione and total protein were estimated in the liver. Aspartate aminotransferase (AST), alanine aminotransferase (ALT), acid and alkaline phosphatase estimations in serum were also carried out. Radiation‐induced increases in the levels of lipid peroxidation (LPO), AST, ALT and acid phosphatase were significantly ameliorated by flaxseed oil pretreatment, and radiation‐induced depletion in the level of glutathione (GSH) and alkaline phosphatase activities was significantly inhibited by flaxseed oil administration. The lifespan was increased in the flaxseed oil treated irradiated mice in comparison with their respective control mice, with survival data showing an LD50/30 (lethal dose for 50% of animals after 30 days) of 7.1 and 10 Gy for control and FO treated irradiated mice, respectively, and produced a dose reduction factor for flaxseed oil (DRF) of 1.40. Radiation‐induced deficits in body and organ weight were significantly reduced or prevented in flaxseed oil pretreated mice. The protection afforded by flaxseed oil may be attributed to the constituents of the oil, which include omega‐3 essential fatty acids and phytoestrogenic lignans, which appear to play an important role in free radical scavenging and singlet oxygen quenching. The study does not rule out the possibility of a prophylactic potential of flaxseed oil against radiation‐induced degenerative changes in liver. Copyright © 2007 John Wiley & Sons, Ltd.
Design in nonlinear mixed effects models: Optimization using the Fedorov–Wynn algorithm and power of the Wald test for binary covariates
Authors: Retout Sylvie , Comets Emmanuelle , Samson Adeline , Mentré France
Published: May 2007

We extend the methodology for designs evaluation and optimization in nonlinear mixed effects models with an illustration of the decrease of human immunodeficiency virus viral load after antiretroviral treatment initiation described by a bi‐exponential model. We first show the relevance of the predicted standard errors (SEs) given by the computation of the population Fisher information matrix using the R function PFIM, in comparison to those computed with the stochastic approximation expectation–maximization algorithm, implemented in the Monolix software. We then highlight the usefulness of the Fedorov–Wynn (FW) algorithm for designs optimization compared to the Simplex algorithm. From the predicted SE of PFIM, we compute the predicted power of the Wald test to detect a treatment effect as well as the number of subjects needed to achieve a given power. Using the FW algorithm, we investigate the influence of the design on the power and show that, for optimized designs with the same total number of samples, the power increases when the number of subjects increases and the number of samples per subject decreases. A simulation study is also performed with the nlme function of R to confirm this result and show the relevance of the predicted powers compared to those observed by simulation. Copyright © 2007 John Wiley & Sons, Ltd.
Micro‐XRF excitation in an SEM
Authors: Haschke M. , Eggert F. , Elam W. T.
Published: May 2007

Electron microscopes are often used for position‐sensitive elemental analysis of non‐homogeneous material by electron‐probe‐micro‐analysis (EPMA). Due to the high spectral background, this method is limited in sensitivity. The availability of x‐ray optics allows the generation of focussed x‐ray beams with spot sizes in the micrometer range. The x‐ray excited spectra have a better peak‐to‐background ratio and, therefore, a higher sensitivity. Further, the excitation efficiency for both electrons and photons varies with the atomic number. Therefore, light elements can be analysed better with electron excitation. The combination of analytical results from electron and x‐ray excitation, therefore, should improve the accuracy of quantification. The paper presents a µ‐XRF excitation unit for scanning electron microscopes (SEMs) and describes the quantification model that is prepared for this device. The quantification is performed for few samples. These results show that the standardless quantification give a good accuracy. Especially in case of presence of light elements like C, O or N in the matrix, the XRF results can be improved by consideration of results from EPMA. Copyright © 2007 John Wiley & Sons, Ltd.
Preparation of substituted 5,6‐dihydro‐4H‐1,3‐oxazines from olefins
Authors: Foglia T. A. , Gregory L. M. , Barr P. A. , Maerker G.
Published: May 2007

The 5,6‐dihydro‐4H‐1,3‐oxazine derivatives of methyl oleate and related compounds have been prepared. These novel six‐membered heterocyclic compounds were obtained by the condensation of N‐hydroxymethyl or N‐chloromethylbenzamide with methyl oleate or its derivatives. These reactions can be regarded as 1,4‐dipolar addition reactions.
Hydrogenation of triple bonds to double bonds in conjugated methyl octadecadiynoate and methyl santalbate
Authors: Morris S. G. , Magidman P. , Herb S. F.
Published: May 2007

A study was made of the noncatalytic hydrogenation of acetylenic bonds in fatty esters tocis double bonds using various metals in different solvent systems. The best results were obtained with 15% propanol in water using iron. The yields ofcis double bonds for the nonconjugated diynoate and monoynoate ranged from 90% to 99% and for the conjugated diynoate the yields ranged from 56% to 77%. In the reduction of methyl santalbate to a conjugated diene, the yields were ca. 85%.
Conjugated hydrogenation of triglyceride oil containing conjugated acid
Authors: Chakrabarty M. M. , Bhattacharyya D. , Basu A. K.
Published: May 2007

Conjugated hydrogenation of tung oil (fatty acid composition: elaeostearic 57.0%, linoleic 25.8%, oleic 11.2% and saturated 6.0%) has been investigated to ascertain the influence of hydrogen donors, namely primary and secondary alcohols, on rate and selectivity under different operating conditions. 2‐Propanol, in general, reflects faster rate and greater degree of reduction but less selectivity towards the reduction of unsaturated acids than ethanol, when tung oil is treated at 200 C, 225 C and 250 C with 2% Ni (optimum catalyst level) and theoretical as well as 100% excess of theoretical amount of the two hydrogen donors to ensure complete hydrogenation of the oil. The rate and degree of reduction with ethanol are less influenced by its amount and amount of catalyst, but with 2‐propanol these depend considerably on both the amount of hydrogen donor and amount of catalyst. During conjugated hydrogenation of tung oil, deposition of gel‐like mass in minor amount occurs only at the wall of the reaction vessel. This is evidently due to polymerization of the conjugated trienoic acid.
Isomers of monoethylenic fatty acids in some partially hydrogenated marine oils
Authors: Conacher H. B. S. , Page B. D. , Chadha R. K.
Published: May 2007

An analytical study of the monoethylenic isomers in commercial samples of partially hydrogenated herring, whale and seal oils is presented. The results show that with hydrogenated herring oil there is a slight decline in monoenetrans content from 37% in C16 through to 32% in C22. With both whale and seal oils, monoenetrans contents were constant at 54% and 59%, respectively, throughout all chain lengths. In general thecis andtrans positional isomers from hydrogenated whale and seal oils were more scattered than those from hydrogenated herring oil; however in each oil the majorcis isomers of each chainlength were indicative of originalcis fatty acid isomers in the raw oils.
Legal frameworks and key concepts regulating diversion and treatment of mentally disordered offenders in european union member states
Authors: Dressing Harald , Salize Hans Joachim , Gordon Harvey
Published: May 2007

Background

There is only limited research on the various legal regulations governing assessment, placement and treatment of mentally ill offenders in European Union member states (EU-member states).

Aims

To provide a structured description and cross-boundary comparison of legal frameworks regulating diversion and treatment of mentally disordered offenders in EU-member states before the extension in May 2004. A special focus is on the concept of criminal responsibility.

Method

information on legislation and practice concerning the assessment, placement and treatment of mentally ill offenders was gathered by means of a detailed, structured questionnaire which was filled in by national experts.

Results

The legal regulations relevant for forensic psychiatry in EU-member states are outlined. Definitions of mental disorders given within these acts are introduced and compared with ICD-10 diagnoses. Finally the application of the concept of criminal responsibility by the law and in routine practice is presented.

Conclusion

Legal frameworks for the processing and placement of mentally disordered offenders varied markedly across EU-member states. Since May 2004 the European Union has expanded to 25 member states and in January 2007 it will reach 27. With increasing mobility across Europe, the need for increasing trans-national co-operation is becoming apparent in which great variation in legal tradition pertains.
Non-pharmacological treatment of psychiatrists in addition to the prescribing of an antidepressant drug
Authors: Linden M. , Dierkes W. , Munz T.
Published: May 2007

Background

Guidelines for the treatment of depression regularly emphasize that pharmacotherapy of depression should be accompanied by supportive counseling and other psychotherapeutic interventions. It is unknown which role psychiatrists in routine care give to such verbal therapies.

Methods

in a drug utilization study of venlafaxine, psychiatrists in private practice and in hospitals were asked to tell what non-pharmacological therapies they saw as an important part of the treatment of the present depressive episode. Additionally patient characteristics, treatment variables, setting characteristics and physician characteristics were assessed.

Results

Psychiatrists reported some kind of verbal therapies in 19.0% of outpatients and 36.8% of inpatients. Verbal therapies were reported more often for younger patients, who got more double diagnoses and were more severely ill. Patients with verbal therapies got more psychotropic medication. in the inpatient setting verbal therapies were related to generally more treatment overall and a higher rate of treatment response. in both treatment settings verbal therapies were related to lower rates of discontinuation of the antidepressant.

Conclusion

Verbal interactions are part of any patient–physician encounter and should be theory guided as part of the therapeutic process in the treatment of depressive disorders. Under this assumption the rate of patients for which psychiatrists reported some kind of verbal therapy as explicit part of their treatment could be higher. More research is needed on patient guidance, counseling and supportive psychotherapy in psychiatry.
N‐Acetylaspartic acid promotes oxidative stress in cerebral cortex of rats
Authors: Pederzolli Carolina D. , Mescka Caroline P. , Scapin Fernanda , Rockenbach Francieli J. , Sgaravatti Ângela M. , Sgarbi Mirian B. , Wyse Angela T.S. , Wannmacher Clóvis M.D. , Wajner Moacir , Dutra‐Filho Carlos S.
Published: May 2007

N‐Acetylaspartic acid accumulates in Canavan Disease, a severe leukodystrophy characterized by swelling and spongy degeneration of the white matter of the brain. This inherited metabolic disease, caused by deficiency of the enzyme aspartoacylase, is clinically characterized by severe mental retardation, hypotonia and macrocephaly, and also generalized tonic and clonic type seizures in about half of the patients. Considering that the mechanisms of brain damage in this disease remain not fully understood, in the present study we investigated whether oxidative stress is elicited by N‐acetylaspartic acid. The in vitro effect of N‐acetylaspartic acid (10–80 mM) was studied on oxidative stress parameters: total radical‐trapping antioxidant potential (TRAP), total antioxidant reactivity (TAR), chemiluminescence, thiobarbituric acid‐reactive substances (TBA‐RS), reduced glutathione content, sufhydryl content and carbonyl content in the cerebral cortex of 14‐day‐old rats. The effect of the acute administration of N‐acetylaspartic acid (0.1–0.6 mmol/g body weight) was studied on TRAP, TAR, carbonyl content, chemiluminescence and TBA‐RS. TRAP, TAR, reduced glutathione content and sulfhydryl content were significantly reduced, while chemiluminescence, TBA‐RS and carbonyl content were significantly enhanced by N‐acetylaspartic acid in vitro. The enhancement in TBA‐RS promoted by N‐acetylaspartic acid was completely prevented by ascorbic acid plus Trolox, and partially prevented by glutathione and dithiothreitol. The acute administration of N‐acetylaspartic acid also significantly reduced TRAP and TAR, and significantly enhanced carbonyl content, chemiluminescence and TBA‐RS. Our results indicate that N‐acetylaspartic acid promotes oxidative stress by stimulating lipid peroxidation, protein oxidation and by decreasing non‐enzymatic antioxidant defenses in rat brain. This could be another pathophysiological mechanism involved in Canavan Disease.
Ground vibrations produced by rock motions and debris flows
Authors: Huang Ching‐Jer , Yin Hsiao‐Yuen , Chen Chao‐Yi , Yeh Chih‐Hui , Wang Chin‐Lun
Published: May 2007

In this study we compare ground vibrations generated by various rocks and debris flows at the same channel to explore the origin of ground vibrations caused by debris flows. In field experiments we identified the ground vibrations caused by motions of individual rocks. Ground vibrations were detected by geophones and analyzed in the time‐frequency domains. We found that ground vibrations caused by individual rocks were 10–150 Hz and that larger stones generate ground vibrations with lower peak frequencies. A sphere‐packing model of granular rocks was used to estimate the propagation speed of ground vibrations. This was found to be underestimated when compared with our experimental data. The signal decay rate was obtained under the assumption that ground vibrations propagate as exponentially attenuating cylindrical waves. Ground vibrations produced by a debris flow at Ai‐Yu‐Zi Creek, Nan‐Tou, Taiwan, on 2 July 2004 revealed that the debris flow forefront produced vibrations lower than 50 Hz and ranged between 50 and 100 Hz after the front had passed. When the main front was closest to the sensor, the frequency spectrum covered a wide range, from 10 to 250 Hz. The mean velocity of the debris flow front was 13.3 m/s. Frequencies of ground vibrations caused by individual rocks are within the frequency range of ground vibrations captured during the debris flow, confirming that one of the main sources of ground vibration caused by debris flows is the interaction of rocks or boulders with the channel bed.
Solar corona–induced fluctuations on spacecraft signal amplitude observed during solar superior conjunctions of the Cassini spacecraft
Authors: Morabito David D.
Published: May 2007

During the superior solar conjunctions of interplanetary spacecraft, the emitted radio signals undergo increased amplitude scintillation, phase scintillation, and spectral broadening due to the intervening charged particles of the solar corona. The magnitude of these parameters generally increases as the angle between the spacecraft and the center of the Sun (Sun‐Earth probe (SEP) angle) decreases as observed by the tracking station on Earth. During periods of quiescent background, the scintillation and spectral broadening measurements of spacecraft in the ecliptic follow well‐defined trends of established models as a function of SEP angle and link frequency. The amplitude data acquired from the Cassini solar superior conjunctions of May 2000 and June 2001 during the maximum of Solar Cycle 23 were analyzed. The X band (8.4 GHz) and Ka band (32 GHz) scintillation measurements from the signal amplitude, the autocorrelation function of the amplitude, and the histogram of the amplitude samples acquired during quiescent periods were found to be consistent with models based on previous studies with other wavelengths. Amplitude autocorrelation functions of the signal amplitude yield information on the limiting scale sizes of the charged‐particle blobs which constitute the solar corona. Evidence for very fast fluctuations at X band (∼3 ms) was observed at SEP angles near 0.6°. The histograms of the open‐loop receiver amplitude samples were found to be consistent with the Rice distribution. The transition from strong to weak scintillation at Ka band was clearly captured in a Cassini 2001 solar conjunction pass that occurred near an SEP angle of 0.6° (2.3 RS) as was expected for this frequency. The existing scintillation models were validated for Ka band, which is planned as a link frequency for deep space communications for upcoming missions. These results from this study are useful in providing information on solar activity on spacecraft signals at both X band and Ka band, which can be used to develop telecommunication strategies during solar superior conjunctions of planetary spacecraft.
Source of whistler emissions at the dayside magnetopause
Authors: Vaivads A. , Santolík O. , Stenberg G. , André M. , Owen C. J. , Canu P. , Dunlop M.
Published: May 2007

Observations of whistler emissions are common in the magnetosphere near the dayside magnetopause. We show that one of the major source regions for these emissions is magnetic field minima that form along magnetic flux tubes at high latitudes. Using multispacecraft Cluster observations we experimentally confirm for the first time the existence of the magnetic field minima at high latitudes and we show that whistler emissions propagate away from the magnetic field minima. The strongest whistler emissions are observed on the magnetospheric flux tubes that are newly opened due to the magnetic reconnection. These flux tubes still have a density of magnetospheric plasma, but part of the high energy magnetospheric electrons have already been lost from the flux tubes. The partial loss of high energy electrons most probably causes anisotropy in electron distributions at high energies which should be the source of whistler emissions. Whistler emissions on opened flux tubes disappear as soon as the plasma density of flux tubes increases due to the entering of magnetosheath ions. We speculate that whistler emissions can most probably be used to trace the dynamics of the first opened field lines and thus the dynamics of magnetic reconnection sites.
Factors controlling CO2 exchange on timescales from hourly to decadal at Harvard Forest
Authors: Urbanski S. , Barford C. , Wofsy S. , Kucharik C. , Pyle E. , Budney J. , McKain K. , Fitzjarrald D. , Czikowsky M. , Munger J. W.
Published: May 2007

We analyzed 13 years (1992−2004) of CO2 flux data, biometry, and meteorology from a mixed deciduous forest in central Massachusetts. Annual net uptake of CO2 ranged from 1.0 to 4.7 Mg‐C ha−1yr−1, with an average of 2.5 Mg‐C ha−1yr−1. Uptake rates increased systematically, nearly doubling over the period despite forest age of 75–110 years; there were parallel increases in midsummer photosynthetic capacity at high light level (21.5−31.5 μmole m−2s−1), woody biomass (101−115 Mg‐C ha−1 from 1993−2005, mostly due to growth of one species, red oak), and peak leaf area index (4.5−5.5 from 1998–2005). The long‐term trends were interrupted in 1998 by sharp declines in photosynthetic capacity, net ecosystem exchange (NEE) of CO2, and other parameters, with recovery over the next 3 years. The observations were compared to empirical functions giving the mean responses to temperature and light, and to a terrestrial ecosystem model (IBIS2). Variations in gross ecosystem exchange of CO2 (GEE) and NEE on hourly to monthly timescales were represented well as prompt responses to the environment, but interannual variations and long‐term trends were not. IBIS2 simulated mean annual NEE, but greatly overpredicted the amplitude of the seasonal cycle and did not predict the decadal trend. The drivers of interannual and decadal changes in NEE are long‐term increases in tree biomass, successional change in forest composition, and disturbance events, processes not well represented in current models.
Identification of organic matter sources in sulfidic late Holocene Antarctic fjord sediments from fossil rDNA sequence analysis
Authors: Coolen Marco J. L. , Volkman John K. , Abbas Ben , Muyzer Gerard , Schouten Stefan , Sinninghe Damsté Jaap S.
Published: May 2007

The 18S ribosomal DNA (rDNA) isolated from sulfidic Holocene sediments and particulate organic matter in the water column of the stratified Small Meromictic Basin (SMB) in Ellis Fjord (eastern Antarctica) was analyzed to identify possible biological sources of organic matter. Previous work had shown that the sediments contained numerous diatom frustules and high contents of a highly branched isoprenoid (HBI) C25:2 alkene (which is a specific biomarker of certain species of the diatom genera Navicula, Haslea, Pleurosigma, or Rhizosolenia), so we focused our search on preserved fossil 18S rDNA of diatoms using sensitive polymerase chain reaction (PCR) approaches. We did not find diatom‐derived fossil 18S rDNA using general eukaryotic primers, and even when we used primers selective for diatom 18S rDNA, we only identified a Chaetoceros phylotype, which is known to form cysts in the SMB but is not a likely source of the C25:2 HBI. When we used PCR/denaturing gradient gel electrophoresis methods specific to phylotypes within the HBI‐biosynthesizing genera, we were able to identify three phylotypes in the sediments related to HBI‐producing strains of the genera Haslea and Navicula. The ancient DNA data thus provided a limited, but valuable, view of the diversity of late Holocene primary producers with a particular bias to specific components of the biota that were better preserved such as the Chaetoceros cysts. This use of paleogenetics also revealed unexpected possible sources of organic matter such as novel stramenopiles for which no specific lipid biomarkers are known and thus would not have been identified based on traditional lipid stratigraphy alone.
Characteristics of cirrus clouds from ICESat/GLAS observations
Authors: Eguchi Nawo , Yokota Tatsuya , Inoue Gen
Published: May 2007

Cloud observations from the Geoscience Laser Altimeter System (GLAS) revealed characteristics of cirrus clouds in boreal autumn 2003. The vertical distribution of the central altitude of cirrus peaks 2 km below the climatological tropopause, which is 14.5 km in the tropics and 9.5 km in the northern midlatitudes. The mean location of the peak in deep convection is north of the Equator (7.5°N) but the top of zonally averaged cirrus is almost constant at 14.5 km in the tropics. This suggests that the height of tropical cirrus is closely linked to anvil cirrus from deep convection and lower temperatures in the tropopause symmetric with respect to the Equator. Cirrus clouds in the midlatitudes have a greater optical depth than those at other latitudes. The zonally averaged thickness of cirrus is about 1.6 km regardless of latitude.
Possible evidence for a double crossing phase transition in D″ beneath Central America from inversion of seismic waveforms
Authors: Kawai Kenji , Takeuchi Nozomu , Geller Robert J. , Fuji Nobuaki
Published: May 2007

We invert seismic body‐wave waveform data for the vertical dependence of (isotropic) shear‐velocity in the D″ layer beneath Central America, using the transverse components of relatively long period broadband waveforms (20–200 s) as data. Our models suggest that the S‐velocity increase in D″ may be localized in the zone from 100–200 km above the core‐mantle boundary (CMB), while the S‐velocity does not significantly deviate from PREM in the zone from 0–100 km above the CMB. This suggests the possible existence of a double crossing (a reverse phase transition from post‐perovskite back to perovskite) at a depth of 100 km above the CMB. Resolution tests indicate that our methods and data can resolve the vertical velocity profile within D″, and that the lower half of D″ is especially well resolved.