bluuebunny/crossref_metadata_2025 huggingface dataset:
The Response of the Southern Hemisphere Atmospheric Circulation to an Enhanced Greenhouse Gas Forcing
Authors: Brandefelt Jenny , Källén Erland
Published: November 2004

The response of the atmospheric circulation to an enhanced radiative greenhouse gas forcing is investigated. It has been proposed that the response of the climate system to an enhanced forcing projects directly onto the preexisting natural modes of variability. An evaluation of this possibility and in particular of the implications of unchanged flow regimes is performed with a focus on the Southern Hemisphere extratropical atmospheric circulation. Low-pass-filtered mean sea level pressure and geopotential height at 500 and 200 hPa from a transient integration with a coupled global climate model is used.

The response to an enhanced forcing projects strongly onto the leading modes of present-day variability, in agreement with other studies. However, the spatial patterns of the leading modes are changed in response to enhanced forcing. The first and second modes of interweekly variability are the Pacific–South American modes, zonal wavenumber-3 wave trains from the central Pacific to the southern Atlantic. In response to the enhanced forcing, the spatial patterns of these modes change, and the wave train extends along a circumpolar path with amplitude also in the Eastern Hemisphere. This change in the spatial patterns is associated with a strengthening of the waveguide for barotropic Rossby waves.
The Theory of Ice Nucleation by Heterogeneous Freezing of Deliquescent Mixed CCN. Part I: Critical Radius, Energy, and Nucleation Rate
Authors: Khvorostyanov Vitaly I. , Curry Judith A.
Published: November 2004

This paper extends previous work on the theory of heterogenous ice nucleation. The goals of this analysis are to explain empirical observations of ice nucleation and to provide a suitable framework for modeling and parameterizing the ice nucleation process in cloud-scale and large-scale atmospheric models. Considered are the processes of heterogeneous freezing of deliquescent mixed cloud condensation nuclei that may serve as ice nuclei, and the properties of an ice germ critical radius, energy, and nucleation rate of ice crystals are examined as functions of temperature and supersaturation. Expressions for nucleation in a polydisperse aerosol for the deliquescence-freezing mode are developed. Equations are derived for the threshold and critical saturation ratios as functions of temperature and nucleation rate, and for the threshold and critical temperatures as functions of saturation ratio. Equivalence of the new formulation for the freezing point depression with traditional expressions is shown and the concepts of the effective temperature and supercooling are introduced. These new formulations are used in a companion paper for simulations of ice nucleation using a cloud parcel model.
Small-Scale Mixing, Large-Scale Advection, and Stratospheric Tracer Distributions
Authors: Vanneste J.
Published: November 2004

The vertical mixing of tracers in the stratosphere is mainly due to patches of three-dimensional turbulence, which are highly intermittent in time and space. A simple heuristic model of this form of mixing is developed and employed to examine the effect of small-scale mixing on passive stratospheric tracers. The model is based on random-walk ideas, and it leads to an analog of the usual advection–diffusion equation in which the diffusion operator is replaced by a convolution operator taking the intermittency of the mixing into account. In its simplest form, this operator is defined by two parameters; these are estimated from midlatitude lower-stratospheric balloon data using a stochastic model of turbulent patches.

The behavior of tracer distributions in some idealized flows shows how intermittency makes mixing less effective in damping the small-scale tracer fluctuations that arise through differential advection. This has consequences for stratospheric tracer distributions, which are demonstrated using numerical simulations based on observed stratospheric winds. Specifically, the new model of mixing leads to a horizontal tracer spectrum that is shallower, and closer to a k−2 power law, than the spectrum obtained with a diffusive parameterization of mixing. The horizontal scale below which intermittent mixing differs significantly from diffusion is estimated to be 15 km or so; remarkably, this coincides with the dissipative scale below which dissipation by small-scale mixing is crucial for tracer evolution.
Dynamics of 2-Day Equatorial Waves
Authors: Haertel Patrick T. , Kiladis George N.
Published: November 2004

The dynamics of the 2-day wave, a type of convectively coupled disturbance that frequents the equatorial western Pacific, is examined using observations and a linear primitive equation model. A statistical composite of the wave's kinematic and thermodynamic structure is presented. It is shown that 1) the wave's wind and temperature perturbations can be modeled as linear responses to convective heating and cooling, and 2) the bulk of the wave's dynamical and convective structure can be represented with two vertical modes. The observations and model results suggest that the 2-day wave is an n = 1 westward-propagating inertio–gravity wave with a shallow equivalent depth (14 m) that results from the partial cancelation of adiabatic temperature changes due to vertical motion by convective heating and cooling.
Influence of Early Winter Upward Wave Activity Flux on Midwinter Circulation in the Stratosphere and Troposphere
Authors: Karpetchko Alexei , Nikulin Grigory
Published: November 2004

Using NCEP–NCAR reanalysis data the authors show that the November–December averaged stratospheric eddy heat flux is strongly anticorrelated with the January–February averaged eddy heat flux in the midlatitude stratosphere and troposphere. This finding further emphasizes differences between early and midwinter stratospheric wave flux behavior, which has recently been found in long-term variations. Analysis suggests that the intraseasonal anticorrelation of stratospheric heat fluxes results from changes in the upward wave propagation in the troposphere. Stronger (weaker) upward wave fluxes in early winter lead to weaker (stronger) upward wave fluxes from the troposphere during midwinter. Also, enhanced equatorward wave refraction during midwinter (due to the stronger polar night jet) is associated with weak heat flux in the early winter. It is suggested that the effect of enhanced midwinter upward wave flux from the troposphere in the years with weak early winter heat flux overcompensates the effect of increased equatorward wave refraction in midwinter, leading to a net increase of midwinter upward wave fluxes into the stratosphere.
A study into the educational needs of children's hospice doctors: a descriptive quantitative and qualitative survey
Authors: Amery Justin , Lapwood Susie
Published: November 2004

Objectives: To identify and explore the educational needs of children's hospice doctors in England. Design: A descriptive quantitative and qualitative survey. Setting: Children's hospices in England. Participants: All children's hospice doctors (n=55) in England were approached, and 35 (65%) consented. Interventions: A questionnaire designed to survey doctors' self-assessed educational competencies (confidence and perceived need for training) in subject areas derived from analysis of existing children's palliative care literature. Educational diaries used prospectively in practice to identify areas of unmet educational need. Main outcome measures: Self-perceived confidence and usefulness scores for each subject area. An analysis of support, education and training needs deriving from educational diaries and one-to-one interviews. Results: Confidence and usefulness scores suggest that respondents would most value support, education and training in the management of emergencies, symptoms and physical disease. Educational diary analysis revealed that respondents would most value support, education and training in communication skills, team-working skills, and personal coping strategies. Conclusions: There is a disparity between educational needs as derived from self-rated competencies and from educational diary keeping; suggesting that Children's hospice doctors may not be fully aware of their own educational, support and training needs. Self-rated competencies emphasise the value of education in craft or clinical skills; whereas personal diary keeping emphasises the value of education in intrapersonal and interpersonal skills such as communication, team-working and personal coping skills. The current curricula and educational resources need to acknowledge that interpersonal and intrapersonal competencies are as important as clinical competencies. While the study looks particularly at the educational needs of children's hospice doctors, readers may feel that the findings are of relevance to all specialities and disciplines.
Hammers and nails: a report
Authors: Sugden C J , Laird B JA
Published: November 2004

A case report where parathyroid bone disease simulates bone metastases. Subsequent treatment of underlying hyperparathyroidism causes a marked improvement in bone disease, leading to a review of the initial diagnosis.
A survey of the perspectives of specialist palliative care providers in the UK of inpatient respite
Authors: Payne S , Ingleton C , Scott G , Steele K , Nolan M , Carey I
Published: November 2004

One of the major reasons for admission of patients to hospital in late stage disease is the inability of carers to continue to provide care at home. Specialist palliative care services have typically admitted patients for acute symptom control, terminal care and respite care to benefit them and their carers. This paper reports the results of a cross-sectional survey of inpatient respite care provision provided by specialist palliative care services and hospices in the UK. A structured questionnaire was mailed to 242 clinical services managers listed in the Hospice Information Directory in 2003. A 69% response rate was achieved. The questionnaire explored the nature of respite services, their purpose, organization, delivery and examined definitions used. The analysis indicated that 80% of the sample provided inpatient respite care. Most inpatient respite admissions were planned, of fixed duration (7–14 days) and were intended to benefit patients and carers. There was some evidence that respite provision was regarded as a lower priority than admissions for symptom control and terminal care, and that patients' needs were prioritized over those of carers. Only 10% of services conducted regular, routine audit, with very few seeking the views of service users. Findings suggest that carers' needs and wishes are not prioritized by specialist palliative care services offering inpatient respite, which may mean that they find it difficult to maintain their caregiving roles over longer disease trajectories or in the face of overwhelming demands.
Attitudes and experiences of Oregon hospice nurses and social workers regarding assisted suicide
Authors: Miller Lois L , Harvath Theresa A , Ganzini Linda , Goy Elizabeth R , Delorit Molly A , Jackson Ann
Published: November 2004

Background: When the Oregon Death with Dignity Act (ODDA) legalizing physician assisted suicide was enacted into law in 1997, Oregon hospice clinicians were uncertain how involved they would be with patients who wanted this option. However, 86% of the 171 persons in Oregon who have died by lethal prescription were enrolled in hospice programmes. Method: A mailed questionnaire was sent to all hospice nurses and social workers in Oregon in 2001 (n = 573) to assess their attitudes about legalized assisted suicide and interactions with patients concerning this issue. Responses from 306 nurses and 85 social workers are included in this report. Findings: Almost two-thirds of respondents reported that at least one patient had discussed assisted suicide as a potential option in the past year. Social workers were generally more supportive of both the ODDA and of patients choosing assisted suicide compared to nurses. Twenty-two per cent of all respondents were not comfortable discussing assisted suicide with patients. Ninety-five per cent of both groups, however, favoured hospice policies that would allow a patient to choose assisted suicide while enrolled in hospice and allow hospice clinicians to continue to provide care. Interpretations: Nurses and social workers in hospices and other settings can expect to encounter patient questions about physician-assisted suicide, whether legalized or not, and must be prepared to have these discussions. Most hospice professionals in Oregon do not believe that assisted suicide and hospice enrolment are mutually exclusive alternatives.
Patrick Geddes, Lewis Mumford and Jean Gottmann: divisions over ‘megalopol is’
Authors: Baigent Elizabeth
Published: November 2004

The term ‘megalopolis’, meaning a large city, was in use in the general press by the 1820s: its occurrence in the scholarly press largely reflects use in the twentieth century by Patrick Geddes and Lewis Mumford to denote an overlarge city doomed to destruction, and by Jean Gottmann to denote a large and highly connected urban region, notably that in the northeastern USA. Gottmann's definition dominates dictionaries of geography, but is ignored outside the discipline. The Oxford English dictionary is urged to recognize Gottmann's (and hence geographers') usage: compilers of geographical dictionaries are urged to revise their definitions.
Synthesis and Formation Mechanism of Silver Nanowires by a Templateless and Seedless Method
Authors: Zhao Qitao , Qiu Jianrong , Zhao Chongjun , Hou Lisong , Zhu Congshan
Published: November 2004

Silver nanowires in large quantities can be obtained through a simple method in the absence of a surfactant or polymer and without addition of external seeding nanocrystallites. A plausible mechanism was proposed to elucidate the formation mechanism of silver nanowires based on TEM studies.
Bloodless removal of varicose veins - a new technique
Authors: Lorenz D , Kullich W , Redtenbacher M , Weissenhofer W
Published: November 2004

Objective: To describe the use of a novel electric vein stripper (EVS) for use in patients with varicosities of the greater saphenous vein and tributaries.

Methods: In addition to standard procedures as performed in varicose veins of the lower limb, an EVS, powered by a standard high frequency electrocoagulation generator (HF), is introduced. The application of this new EVS makes it possible to avoid tearing of the structures of the subcutaneous tissue surrounding the greater saphenous vein, leaving the channel of the vein blood dry.

Results: A preliminary study including two groups of patients - 20 in the Babcock group and 24 in the EVS group - resulted in significantly reduced pain and discomfort. An added benefit for the patients was the fact that postoperative compression bandages were not needed.

Conclusions: Application of EVS can prevent bruising and haematomas in vein stripping can be avoided.
Effect of seasonal variations on the emergence of deep venous thrombosis of the lower extremity
Authors: Yetkin U , Karabay Ö , Önol H
Published: November 2004

Objective: We aimed to determine the role of seasonal and meteorological variations in the incidence of lower extremity deep venous thrombosis (DVT).

Methods: A total of 296 patients with DVT for the first time were admitted to the Cardiovascular Surgery Clinic of the Alsancak State Hospital during the four-year period between January 1999 and December 2002. Of these cases, 151 were women (51%) and the average age was 58.8 years. We investigated the effect of each month and season on the onset of acute symptoms of DVT. Meteorological data were also compared during the onset of disease.

Results: We found that DVT frequency significantly increased during the six-month period between October and March, particularly on the coldest winter days and when atmospheric pressure was low.

Conclusions: Lower extremity DVT significantly correlates with meteorological variables such as cold temperatures and low atmospheric pressure. Further multicentric prospective studies are necessary to determine the extent of these effects.
Long-term treatment of chronic venous insufficiency of the leg with micronized purified flavonoid fraction in the primary care setting of India
Authors: Pinjala R K , Abraham T K , Chadha S K , Hai A A , Hussain S A , Moulik A K , Nagori L F , Nayak G , Patel M D , Sen G , Shetty S V , Sinha K N
Published: November 2004

Objective: This study investigates whether micronized purified flavonoid fraction (MPFF) is effective and acceptable without compression or surgical intervention for the management of chronic venous insufficiency of the leg (CVIL) in the primary care setting of a tropical country such as India.

Methods: A prospective observational study on patients with early CVIL drawn from the clinical practice of randomly selected physicians distributed across India. Patients received MPFF 1000 mg/day for six months without compression stockings or surgery. The primary outcome was a change in their CEAP (clinical, aetiological, anatomical, pathophysiological) classification of CVIL severity. Secondary outcomes were changes in leg oedema, symptom intensity and quality of life.

Results: Of the 308 patients recruited by 72 physicians, 166 (53.9%, 95% confidence interval (CI) 48.3-59.5) had regression in the CEAP severity stage. Mean leg circumference in those with oedema decreased by 2 cm (95% CI 1.7-2.3, P <0.05). Patient-assessed mean percentage decrease in symptom intensity was 32.3 for cramps (28.9-35.7, P <0.01); 32.4 for heaviness (29.8-35.7, P <0.01); 28.2 for pain (25.6-30.8, P <0.01); and 21.5 for swelling (18.7-24.3, P <0.01). Quality of life improved by 21.7% (16.9-26.5, P <0.01) in the physical domains, 25.9% (20.8-31.0, P <0.01) in the social domains, and 19.2% (14.7-23.7, P <0.01) in the psychological domains.

Conclusions: When used alone, MPFF was effective and acceptable for the management of CVIL in primary care. This may be useful in tropical climates where compliance with compression stockings is poor and access to surgery limited.
Pharmacy-based assessment of adherence to HAART predicts virologic and immunologic treatment response and clinical progression to AIDS and death
Authors: Kitahata Mari M , Reed Shelby D , Dillingham Peter W , Van Rompaey Stephen E , Young Alicia A , Harrington Robert D , Holmes King K
Published: November 2004

Although adherence to HAART at a level above 95% has been associated with optimal viral suppression, the impact of different levels of adherence on long-term clinical outcomes has not been determined. We used an objective pharmacy-based measure to examine the association between three levels of adherence to HAART and disease progression among a population-based cohort of HIV-infected patients attending an urban HIV specialty clinic. Higher levels of adherence to HAART were significantly associated with longer time to virologic failure ( P < 0.001), greater increase in CD4 cell count ( P = 0.04), and lower risk of progression to clinical AIDS or death ( P < 0.007). After controlling for other factors, patients with low adherence had over five times the risk of disease progression than patients with moderate adherence ( P = 0.007) or patients with high adherence ( P = 0.001). There was no significant difference in the risk of progression between patients with moderate and high levels of adherence ( P > 0.2). Patients who progressed to AIDS or death had significantly higher viral loads ( P = 0.01) and lower CD4 cell counts ( P = 0.03) than patients who experienced virologic failure, but did not progress.
Chlamydial infection in women along the US–Mexico border
Authors: Baldwin S B , Djambazov B , Papenfuss M , Abrahamsen M , Denman C , Guernsey de Zapien J , Ortega L , Navarro Henze J L , Hunter J , Rojas M , García F , Giuliano A R
Published: November 2004

Few studies have reported on sexually transmitted infections at the US–Mexico border, so the prevalence of Chlamydia trachomatis in this population remains uncertain. This binational project investigated the prevalence of, and risk factors for, C. trachomatis among women along the Arizona, US–Sonora, Mexico border.

Women who self-referred for routine gynaecological care were invited to complete an interviewer-administered questionnaire and to undergo a Pap smear, C. trachomatis test, and HPV test. In 2270 women, C. trachomatis prevalence overall was 8.2% as measured by hybrid capture and 2.6% by enzyme immunoassay. Infection was associated with young age, a history of new sexual partner(s) in the previous three months, HPV infection, and proximity of clinic to the international border. Antibiotic use in the previous 30 days was associated with decreased odds of infection.

Women in Arizona–Sonora border communities are at increased risk for C. trachomatis infection compared to women attending clinics in non-border locations.
Problems with change in R2 as applied to theory of reasoned action research
Authors: Trafimow David
Published: November 2004

The paradigm of choice for theory of reasoned action research seems to depend largely on the notion of change in variance accounted for (ΔR2) as new independent variables are added to a multiple regression equation. If adding a particular independent variable of interest increases the variance in the dependent variable that can be accounted for by the list of independent variables, then the research is deemed to be ‘successful’, and the researcher is considered to have made a convincing argument about the importance of the new variable. In contrast to this trend, I present arguments that suggest serious problems with the paradigm, and conclude that studies on attitude‐behaviour relations would advance the field of psychology to a far greater extent if researchers abandoned it.
The Mozart effect: Tracking the evolution of a scientific legend
Authors: Bangerter Adrian , Heath Chip
Published: November 2004

Theories of the diffusion of ideas in social psychology converge on the assumption that shared beliefs (e.g., social representations, rumours and legends) propagate because they address the needs or concerns of social groups. But little empirical research exists demonstrating this link. We report three media studies of the diffusion of a scientific legend as a particular kind of shared belief. We studied the Mozart effect (ME), the idea that listening to classical music enhances intelligence. Study 1 showed that the ME elicited more persistent media attention than other science reports and this attention increased when the ME was manifested in events outside of science. Study 2 suggested that diffusion of the ME may have responded to varying levels of collective anxiety. Study 3 demonstrated how the content of the ME evolved during diffusion. The results provide evidence for the functionality of diffusion of ideas and initial elements for a model of the emergence and evolution of scientific legends.
Dielectric Response in Strongly Disordered Materials: Analytic Approaches
Authors: Schulz M. , Dietrich Wolfgang , Maass P.
Published: November 2004

Interacting dipolar centers at frozen random positions are known to provide a microscopic mechanism for strong non-Debye behavior in the dielectric response. In particular, it has been shown previously by kinetic Monte Carlo simulation that nearly constant dielectric loss spectra emerge from random dipolar lattice gas models. Here we discuss analytic or semi-analytic theories that allow us to treat such complex models that involve structural randomness and electrostatic interactions. After a brief review of a dynamic pair approximation we present a scaling theory which is based on the observation that relaxation of a selected dipole is dominated by the interaction with its closest neighbor. Finally, some first steps in a new, field-theoretic approach are outlined.
Ion Dynamics in Mixed Alkali Borate Glasses
Authors: Cramer Cornelia , Gao Yong , Brunklaus Sabine , Ratai Eva
Published: November 2004

Frequency-dependent conductivities are a valuable tool for studying the ion dynamics on different time scales, the latter being determined by the inverse of the experimental frequency. Therefore, wide range conductivity spectra probe the transition from elementary steps of the ionic movement to macroscopic transport. We have studied the ion dynamics in mixed alkali borate glasses where we have systematically varied the total and the relative ion concentration. The glass system under investigation isy[xLi2O · (1−x) Na2O] · (1−y) B2O3withx= 0.0, 0.2, 0.4, 0.6, 0.8, 1.0 andy= 0.1, 0.2, 0.3. The conductivity spectra can be formally divided into a low-frequency and a high-frequency regime. In the low-frequency regime the conductivities of all glasses show a transition from their dc values into a dispersive regime where the conductivity is found to increase continuously with frequency, tending towards a linear frequency dependence at sufficiently low temperatures. The conductivity spectra can be described by the MIGRATION concept developed by Funke. We discuss the spectral shape of the conductivity spectra and its implications for the ion transport. In addition, we report on a new mixed alkali effect occurring in the high-frequency regime of the ac conductivity. From our results we conclude that apart from a low-frequency contribution to the conductivity which is linked to ion hopping sequencess, there is an additional contribution involving localized motions of both the mobile ions and the glassy network.
Preliminary Biomass Characterization in a Sequencing Batch Biofilm Reactor
Authors: Di Iaconi Claudio , Ramadori Roberto , Lopez Antonio , Passino Roberto
Published: November 2004

The paper reports the results of an investigation aimed to evaluate the influence of hydrodynamic conditions on physical and biochemical characteristics of granular sludge obtained in a SBBR system. Biomass density resulted very high, i.e. 70‐125 gTSS/Lbiomass, and this permitted to achieve a biomass concentration such high as 17‐45 gTSS/Lbed. An appropriate equation proved that the pressure loss, an easily measurable parameter, can be used for biomass porosity measurement and indirect assessment of biomass concentration in the biofilter. As for biomass biochemical characterisation, the EPS (Extracellular Polymeric Substances) content was rather low (5‐7 % of the total organic matter) and mostly made up of proteins whereas the cellular protein content, a parameter frequently used as an indicator of microorganisms activity, was high (30‐60 % of total organic matter).
Identification of Levoglucosan and Related Steroisomers in Fog Water as a Biomass Combustion Tracer by ESI‐MS/MS
Authors: Palma Pierangela , Cappiello Achille , de Simoni Elisa , Mangani Filippo , Trufelli Helga , Decesari Stefano , Facchini Maria Cristina , Fuzzi Sandro
Published: November 2004

A conspicuous fraction of the water soluble organic compounds (WSOC) in fog and fine aerosol samples is composed by monosaccharide anhydrides, such as levoglucosan and its stereoisomers, galactosan and mannosan. Levoglucosan is produced exclusively during wood combustion processes, making it a very useful tracer for plant combustion emissions in the atmosphere. This paper describes a new experimental approach, based on electrospray‐tandem mass spectrometry (ESIMS/ MS), for the identification of levoglucosan in fog water samples. The analytical method proposed allows to identify the specific sugar anhydrides directly in the liquid phase without the need of any derivatization process.
Validation of LC/MS Electrospray Ionisation Method for the Estimation of Ursodiol in Human Plasma and ITS Application in Bioequivalence STUDY
Authors: Sundd Singh Sonu , Shah Hiten , Gupta Sapna , Jain Manish , Sharma Kuldeep , Patel Harshvardhan , Shah Bhavin , Thakkar Purav , Patel Nimesh , Shah Ruchy , Bhushan Lohary Braj
Published: November 2004

A novel High Performance Liquid Chromatography — electrospray mass spectrometric method has been developed for the estimation of Ursodiol (Ursodeoxycholic acid)‐a bile acid, in human plasma using Ornidazole as internal standard. The methodology involved solid phase extraction of the analyte from human plasma matrix. The chromatographic separation was achieved within seven minutes by an isocratic mobile phase containing 1.0 mM ammonium acetate and Acetonitrile (65: 35, v/v), flowing through XTerra MS C18, 100 × 2.1, 3.5 μm analytical column, at a flow rate of 0.2 ml/min. Ion signals were measured in negative mode for Ursodiol and internal standard at m/z 391.3 and 278.1, respectively. A detailed validation of the method was performed as per USFDA guidelines and the standard curves were found to be linear in the range 50.0 ng/ml to 3000.0 ng/ml with the mean correlation coefficient more than 0.99. The absolute recovery was more than 54.90 % for Ursodiol and 76.51 % for internal standard. Ursodiol was stable for sixty‐nine days at −70 °C and for eight hours at ambient temperature. After extraction from plasma, the reconstituted samples of Ursodiol were stable in autosampler at 10 °C for forty‐eight hours. Upon subjecting to three freeze thaw cycles, there was no change in the recovery of the analyte. The integrity of the plasma samples remained unaffected even upon four‐fold dilution with drug free human plasma. The method was simple, specific, sensitive, precise, accurate and suitable for bioequivalence and pharmacokinetic studies. It was successfully applied to the pilot bioequivalence study of Ursodiol in male human subjects.
Cover Picture: Locked Nucleic Acids and Intercalating Nucleic Acids in the Design of Easily Denaturing Nucleic Acids: Thermal Stability Studies (ChemBioChem 12/2004)
Authors: Filichev Vyacheslav V. , Christensen Ulf B. , Pedersen Erik B. , Babu B. Ravindra , Wengel Jesper
Published: November 2004

The cover picture shows fully modified locked nucleic acids (LNAs, orange) and intercalating nucleic acids (INAs®, red) with several insertions of (R)‐1‐O‐(1‐pyrenylmethyl)glycerol, both displaying higher binding affinity to native DNA (white) than to each other. In their full paper on p. 1673 ff, E. B. Pedersen et al. describe the design of easily denaturing nucleic acid duplexes using complementary LNAs and INAs, and how the combined use of these chemically modified nucleic acids can solve the problem of "quenching" due to complementary strands of duplexes or hairpins that otherwise limit their use for DNA targeting.
What do we know about apolipoprotein E and the prevention of cardiovascular disease?
Authors: Tan Chee‐Eng , Tai E. Shyong
Published: November 2004

Apolipoprotein E (ApoE) serves as a ligand for low‐density lipoprotein (LDL) receptor and LDL receptor–related protein and plays an important role in the clearance of triglyceride‐rich lipoproteins. The links between ApoE and cardiovascular disease has been shown in animal models and numerous epidemiological studies. Deletion of the APOE gene in mice resulted in high plasma cholesterol and spontaneous atherosclerosis. Atheroma formation in APOE‐deficient mice can be prevented by expression of ApoE through various genetic transfer techniques. These effects may be independent of the effect on cholesterol levels, suggesting a direct antiatherogenic effect of ApoE. In humans, the APOE genotypes are important determinants of LDL‐C and were highest in subjects with the ϵ4 allele, intermediate in ϵ3 subjects, and lowest in ϵ2 subjects. Targeting APOE expression or ApoE levels represents an attractive means of reversing or preventing atherosclerosis. Infusion of recombinant adenovirus containing ApoE, intramuscular injection of plasmid vector encoding for APOE3 cDNA, or infusion of recombinant ApoE in animal models have all resulted in reduction in cholesterol and prevention of atherosclerosis. The use of peptide models of ApoE in animals has also shown some potential in reducing atherosclerosis. However, the short half‐lives of recombinant ApoE or its peptide models are a limitation to their usefulness. New modalities for drug delivery that allow sustained delivery of ApoE, such as the multivesicular liposome depot‐delivery system (DepoFoam) may pave the way for the use of ApoE as a means of therapy in atherosclerosis prevention. Interactions between APOE genotypes and response to lipid‐lowering therapy is another area of focus when considering the role of ApoE in the prevention of atherosclerosis. Drug Dev. Res. 62:200–206, 2004. © 2004 Wiley‐Liss, Inc.
Pharmacogenomics of the p53 tumor suppressor and its role in cancer chemoresistance
Authors: Liu Suxing , Bishop W. Robert , Dasmahapatra Bimal , Wang Yaolin
Published: November 2004

Drug resistance remains a key obstacle to successful cancer treatment. The implementation of pharmacogenomics is widely proclaimed as a route to revolutionize the face of cancer therapy. Here we discuss the pharmacogenomics of the p53 tumor suppressor and its role in cancer chemosensitivity. It has been proposed that p53 has a profound impact on the response to chemotherapy and participates in development of drug resistance in tumor cells. This is based on the dual role of p53 as a guardian of genome integrity and as a key mediator of apoptosis. Alterations of the p53 gene occur in approximately 50% of human cancer, and human tumor cells retaining wild‐type p53 often have epigenetic defects in the p53 pathway. Extensive mechanistic studies of drug action suggest that virtually all cancer cells have a dysfunctional p53 system (including p53 and its associated proteins, both upstream regulators and downstream targets). Various experimental approaches to correct the p53 pathway defects in tumor cells are discussed. Many studies have correlated p53 status with prognosis and therapy response in tumors. However, the impact of p53 status on drug resistance of tumors is still controversial. The impact of p53 on chemosensitivity is complex and multifactorial, depending on the genotypic/phenotypic context of the cell. Recent technological achievements have fostered a renewed interest in pharmacogenomics of p53 and its association with drug response. These include high‐throughput tissue microarray analysis of p53 protein expression, single nucleotide polymorphism genotyping of the p53 gene, and gene expression profiling to identify the gene signature of p53‐associated chemoresistance. Knowledge from pharmacogenomic studies will provide an opportunity for improvements in drug efficacy through effective stratification of patients, and early identification of those individuals most likely to respond effectively to a specific therapy. Drug Dev. Res. 62:254–272, 2004. © 2004 Wiley‐Liss, Inc.
Aus der Arbeit der Sachverständigenausschüsse: SVA A “Betontechnologie”
Authors: Efes Yakut
Published: November 2004

Bericht über die Arbeit des SVA “Betontechnologie” A: “Grundsatzfragen” in den Jahren 2002 bis 2004
Incorporating uncertainty in chemical process design for environmental risk assessment
Authors: Vasquez Victor R. , Whiting Wallace B.
Published: November 2004

The effects of uncertainty in thermophysical properties on the evaluation of the environmental performance is demonstrated with a chemical process to recover toluene and ethyl acetate by absorption from a gaseous waste stream of a cellophane production plant. In this case study, the environmental performance is defined as the estimation of the volatile organic compounds (VOCs) and total emissions of the plant and of several environmental risk indexes. We found that estimations of VOCs are very sensitive to uncertainty in thermophysical properties such as infinite‐dilution activity coefficients, and vapor pressures (through uncertain temperature variations). Additionally, we concluded that calculation of the total emissions can be very sensitive to fuel content factors such as those used to estimate greenhouse gases. This can have such an impact on the emission calculations that a detailed model of the given chemical process might not be required for the estimation of the total emissions. In other words, a simpler process flowsheet model can perform the same task just as well, with the results within the variations caused by uncertainty in the thermophysical properties. We demonstrate a Monte Carlo approach that allows the detection of such uncertainty characteristics in a design, providing a rational basis for prediction of the associated environmental risks. This procedure also enables the deconvolution of various sources of uncertainty, and the estimation of physical property uncertainty through a similarity approach. We concluded that our framework can be used to enhance decision making by uncovering uncertainties and sensitivities in chemical process simulation. © 2004 American Institute of Chemical Engineers Environ Prog, 2004
Cache replacement policies for P2P file sharing protocols
Authors: Wierzbicki Adam , Leibowitz Nathaniel , Ripeanu Matei , Woźniak Rafał
Published: November 2004

Peer‐to‐peer (P2P) file‐sharing applications generate a large part of today's Internet traffic. The large volume of this traffic (thus high potential caching benefits) and the large cache sizes required (thus non‐trivial costs associated with caching) only underline that efficient cache replacement policies are important in this case. File popularity in P2P file‐sharing networks does not follow Zipf's law and several additional characteristics set the generated traffic apart from well‐studied Web traffic. All this lead us to conduct a focused study of efficient cache management policies for P2P file‐sharing traffic. This paper uses real‐world traces and trace driven simulations to compare traditional cache replacement policies and new policies that exploit characteristics of the P2P file‐sharing traffic generated by applications using FastTrack protocol. Copyright © 2004 AEI
Experimental analysis of the impact of peer‐to‐peer applications on traffic in commercial IP networks
Authors: Ben Azzouna Nadia , Guillemin Fabrice
Published: November 2004

To evaluate the impact of peer‐to‐peer (P2P) applications on traffic in wide area networks, we analyze measurements from a high speed IP backbone link carrying TCP traffic towards several ADSL areas. The first observations are that the prevalent part of traffic is due to P2P applications (almost 80% of total traffic) and that the usage of network becomes symmetric in the sense that customers are not only clients but also servers. This latter point is observed by the significant proportion of long flows mainly composed of ACK segments. When analyzing the bit rate created by long flows, it turns out that the TCP connections due to P2P applications have a rather small bit rate and that there is no evidence for long range dependence. These facts are intimately related to the way P2P protocols are running. We separately analyze signaling traffic and data traffic. It turns out that by adopting a suitable level of aggregation, global traffic can be described by means of usual tele‐traffic models based on M/G/∞ queues with Weibullian service times. Copyright © 2004 AEI
An analytic model for the behavior of arbitrary peer‐to‐peer networks
Authors: Schollmeier Rüdiger , Schollmeier Gero
Published: November 2004

We present an analytic approach to better understand and design peer‐to‐peer (P2P) networks, which are becoming increasingly important, as they contribute an amount of traffic often dominating the total traffic in the internet even today. We start from a graph theoretical approach for infinite random networks and enhance that to include the effects of a finite network. Our approach is valid for an arbitrary degree distribution in the network and thus avoids the need for extensive simulation, which would otherwise be required to evaluate the performance of a specific P2P protocol. Our analytic approach can thus be used for improved tailoring of P2P communication as well as to minimize the often excessive signaling traffic. Copyright © 2004 AEI
Forecasting futures returns in the presence of price limits
Authors: Harel Arie , Harpaz Giora , Yagil Joseph
Published: November 2004

In a futures market with a daily price‐limit rule, trading occurs only at prices within limits determined by the previous day's settlement price. Price limits are set in dollars but can be expressed as return limits. When the daily return limit is triggered, the true equilibrium futures return (and price) is unobservable. In such a market, investors may suffer from information loss if the return “moves the limit.” Assuming normally distributed futures returns with unknown means but known volatilities, we develop a Bayesian forecasting model in the presence of return limits and provide some numerical predictions. Our innovation is the derivation of the predictive density for futures returns in the presence of return limits. © 2005 Wiley Periodicals, Inc. Jrl Fut Mark 25:199–210, 2005
Traders' strategic behavior in an index options market
Authors: Shik Eom Kyong , Buhm Hahn Sang
Published: November 2004

We analyze traders' strategic behavior in an index options market, examining the relationships among expected duration, frequency of trades, trade size, and time to maturity using a modified ACD model. Using intraday data at‐the‐money put and call options, we obtain the following results: (1) Frequency of trades contains more information about future option price volatility than does trade size. This may result from institutional or large traders who have issued naked options using the delta‐neutral strategy to hedge those options. This also suggests that informed traders use their informational advantage little by little, rather than all at once. (2) Option volatility increases as the maturity date approaches, contradicting the prediction of the Black‐Scholes model. (3) The duration of the previous interval has a persistent effect on expected duration of the current interval. (4) For the estimation of the modified ACD model, the standardized distribution of duration is Weibull with γ < 1, not exponential. (5) The duration in the options market exhibits an inverse U‐shaped diurnal pattern, much like that of the U.S. stock market. However, unlike in the U.S. stock market, the index options duration becomes much shorter right before lunch hour (12:00 pm). © 2005 Wiley Periodicals, Inc. Jrl Fut Mark 25:105–133, 2005
Incorporating topographic variability into a simple regional snowmelt model
Authors: Sloan W. T. , Kilsby C. G. , Lunn R.
Published: November 2004

General circulation models (GCMs), or stand‐alone models that are forced by the output from GCMs, are increasingly being used to simulate the interactions between snow cover, snowmelt, climate and water resources. The variation in snowpack extent, and hence albedo, through time in a cell is likely to be substantial, especially in mid‐latitude mountainous regions. As a consequence, the energy budget simulation by a GCM relies on a realistic representation of snowpack extent. Similarly, from a water resource perspective, the spatial extent of the pack is key in predicting meltwater discharges into rivers. In this paper a simple computationally efficient regional snow model has been developed, which is based on a degree‐day approach and simulates the fraction of the model domain covered by snow, the spatially averaged melt rate and the mean snowpack depth. Computational efficiency is achieved through a novel spatial averaging procedure, which relies on the assumptions that precipitation and temperature scale linearly with elevation and that the distribution of elevations in the domain can be modelled by a continuous function. The resulting spatially averaged model is compared with both observations of the duration of snow cover throughout Austria and with results from a distributed model based on the same underlying assumptions but applied at a fine spatial resolution. The new spatially averaged model successfully simulated the seasonal snow duration observations and reproduced the daily dynamics of snow cover extent, the spatially averaged melt rate and mean pack depth simulated by the distributed model. It, therefore, offers a computationally efficient and easily applied alternative to the current crop of regional snow models. Copyright © 2004 John Wiley & Sons, Ltd.
Hydrological model sensitivity to parameter and radar rainfall estimation uncertainty
Authors: Hossain Faisal , Anagnostou Emmanouil N. , Dinku Tufa , Borga Marco
Published: November 2004

Radar estimates of rainfall are being increasingly applied to flood forecasting applications. Errors are inherent both in the process of estimating rainfall from radar and in the modelling of the rainfall–runoff transformation. The study aims at building a framework for the assessment of uncertainty that is consistent with the limitations of the model and data available and that allows a direct quantitative comparison between model predictions obtained by using radar and raingauge rainfall inputs. The study uses radar data from a mountainous region in northern Italy where complex topography amplifies radar errors due to radar beam occlusion and variability of precipitation with height. These errors, together with other error sources, are adjusted by applying a radar rainfall estimation algorithm. Radar rainfall estimates, adjusted and not, are used as an input to TOPMODEL for flood simulation over the Posina catchment (116 km2). Hydrological model parameter uncertainty is explicitly accounted for by use of the GLUE (Generalized Likelihood Uncertainty Estimation). Statistics are proposed to evaluate both the wideness of the uncertainty limits and the percentage of observations which fall within the uncertainty bounds. Results show the critical importance of proper adjustment of radar estimates and the use of radar estimates as close to ground as possible. Uncertainties affecting runoff predictions from adjusted radar data are close to those obtained by using a dense raingauge network, at least for the lowest radar observations available. Copyright © 2004 John Wiley & Sons, Ltd.
Complex wavelets for extended depth‐of‐field: A new method for the fusion of multichannel microscopy images
Authors: Forster Brigitte , Van De Ville Dimitri , Berent Jesse , Sage Daniel , Unser Michael
Published: November 2004

Microscopy imaging often suffers from limited depth‐of‐field. However, the specimen can be “optically sectioned” by moving the object along the optical axis. Then different areas appear in focus in different images. Extended depth‐of‐field is a fusion algorithm that combines those images into one single sharp composite. One promising method is based on the wavelet transform. Here, we show how the wavelet‐based image fusion technique can be improved and easily extended to multichannel data. First, we propose the use of complex‐valued wavelet bases, which seem to outperform traditional real‐valued wavelet transforms. Second, we introduce a way to apply this technique for multichannel images that suppresses artifacts and does not introduce false colors, an important requirement for multichannel optical microscopy imaging. We evaluate our method on simulated image stacks and give results relevant to biological imaging. Microsc. Res. Tech. 65:33–42, 2004. © 2004 Wiley‐Liss, Inc.