bluuebunny/crossref_metadata_2025 huggingface dataset:
Liver Xenografts for the Treatment of Acute Liver Failure: Clinical and Experimental Experience and Remaining Immunologic Barriers
Authors: Hara Hidetaka , Gridelli Bruno , Lin Yih Jyh , Marcos Amadeo , Cooper David K. C.
Published: March 2008

A critical element restricting the application of liver transplantation is the shortage of human deceased donor organs. Xenotransplantation using pig organs might be a solution to this shortage. Although the problems that still require resolution include the immunologic barrier, the potential risk of transferring infectious agents with the transplanted organ, and uncertainty about whether the transplanted organ will function satisfactorily in the human environment, recent progress in the genetic manipulation of pigs has led to the prospect that clinical xenografting, at least as a bridge to allotransplantation, may be possible in the foreseeable future. Experience with clinical auxiliary and orthotopic liver xenotransplantation and experimental liver xenotransplantation in nonhuman primate and other large animal models is reviewed, and the remaining immunologic problems are discussed. Evidence suggests that, in patients with hepatic failure, the pig liver may be less susceptible to antibody-mediated injury than other pig organs, such as the heart or kidney. Pig Kupffer cells and other macrophages will recognize and phagocytose primate red blood cells, but this problem should be overcome by pretransplant depletion of macrophages from the organ-source pig. From the evidence currently available, it does not seem unduly optimistic to anticipate that a liver from an α1,3-galactosyltransferase gene-knockout pig would survive at least long enough to function as a successful bridge to allotransplantation.
Cationic Polyrotaxanes Effectively Inhibit Uptake via Carnitine/Organic Cationic Transporters without Cytotoxicity
Authors: Utsunomiya Hideto , Katoono Ryo , Yui Nobuhiko , Sugiura Tomoko , Kubo Yoshiyuki , Kato Yukio , Tsuji Akira
Published: March 2008

We examined the inhibitory effect of cationic polyrotaxanes, which consist ofα‐cyclodextrins threaded on a poly(ethylene glycol) (PEG) chain, on the activity of the intestinal carnitine/organic cation transporter, OCTN2, in OCTN2 gene‐transfected HEK293/PDZK1 cells. The cationic polyrotaxanes effectively inhibited the OCTN2‐mediated carnitine transport. Polyrotaxanes with a longer PEG chain exhibited a greater inhibitory effect, possibly owing to multivalent interactions with binding sites on OCTN2. These cationic polyrotaxanes were far less cytotoxic than conventional polycations, and are therefore interesting candidates as low‐toxicity inhibitors of cation transport at cell surfaces.

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pH‐Switchable Complexation between Double Hydrophilic Heteroarm Star Copolymers and a Cationic Block Polyelectrolyte
Authors: Ge Zhishen , Xu Jian , Wu Danlu , Narain Ravin , Liu Shiyong
Published: March 2008

Double hydrophilic heteroarm star copolymers of poly(methacrylic acid) (PMAA) and poly(ethylene oxide) (PEO) were synthesized via atom‐transfer radical polymerization (ATRP) using the “in‐out” method. The synthesis consisted of three steps. Namely, ATRP was applied to the preparation of a star macroinitiator with PEO arms and a cross‐linked core resulting from the polymerization of divinylbenzene (DVB) in the first step, chain extension with tert‐butyl methacrylate (tBMA) under ATRP conditions, and subsequent hydrolysis of the tert‐butyl groups afforded (PEO)n‐PDVB‐(PMAA)n heteroarm star copolymers with a cross‐linked microgel core. This novel type of double hydrophilic heteroarm star copolymer can be considered as unimolecular micelles with hybrid coronas. The star copolymers exhibited pH‐dependent solubility in water, being soluble at high pH and insoluble at low pH, due to the formation of hydrogen‐bonded complexes between the PEO and PMAA arms. A mixed solution of the heteroarm star copolymer and a PEO‐b‐PQDMA diblock copolymer, where PQDMA is poly(2‐(dimethylamino)ethyl methacrylate) fully quaternized with methyl iodide, remained stable in the whole pH range, and exhibited an intriguing pH‐switchable complexation behavior accompanied with structural rearrangement.

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Regression of symptoms after selective iron chelation therapy in a case of neurodegeneration with brain iron accumulation
Authors: Forni Gian Luca , Balocco Manuela , Cremonesi Laura , Abbruzzese Giovanni , Parodi Roberto Carlo , Marchese Roberta
Published: March 2008

We report the results of iron chelating treatment with deferiprone in a 61‐year‐old woman with signs and symptoms of neurodegeneration with brain iron accumulation (NBIA). After 6 months of therapy the patient's gait had improved and a reduction in the incidence of choreic dyskinesias was observed. Her gait returned to normal after an additional 2 months of therapy, at which time there was a further reduction in involuntary movements and a partial resolution of the blepharospasm. © 2008 Movement Disorder Society
The Self‐report Standardized Assessment of Personality‐abbreviated Scale: Preliminary results of a brief screening test for personality disorders
Authors: Germans Sara , Van Heck Guus L. , Moran Paul , Hodiamont Paul P.G.
Published: March 2008

Objective The internal consistency, test–retest reliability and validity of the Self‐report Standardized Assessment of Personality‐abbreviated Scale (SAPAS‐SR) as a screening instrument for personality disorders were studied in a random sample of 195 Dutch psychiatric outpatients, using the Structured Clinical Interviews for DSM‐IV Personality Disorders (SCID‐II) as a gold standard.

Method All patients completed a self‐report version of the SAPAS. One week later, they were interviewed with the SCID‐II. Two weeks later, the SAPAS‐SR was re‐administered.

Results According to the SCID‐II, 97 patients (50%) were suffering from a personality disorder. The SAPAS‐SR correctly classified 81% of all participants. Sensitivity (0.83) and specificity (0.80) were slightly lower compared with the original English version. This difference may be explained by the lower prevalence and severity of personality disorders in the study population.

Conclusion The results provide evidence for the usefulness of the SAPAS as a self‐administered instrument for screening personality disorders in clinical populations. Copyright © 2008 John Wiley & Sons, Ltd.
Oleum and Chlorosulfonic acid spill tests—preliminary field data for model validation
Authors: Dharmavaram S.
Published: March 2008

Oleums are mixtures of sulfur trioxide in sulfuric acid and are produced in several strengths. Chlorosulfonic acid (CSA) is formed by reacting sulfur trioxide with hydrochloric acid (HCl). These chemicals are used as sulfating and sulfonating agents in many applications. When accidentally released from vessels or pipes, they react instantaneously with water available from all sources like atmosphere, concrete, soil, and so forth, to form a fine acid mist that disperses downwind, based on atmospheric conditions. Unlike most other chemicals, the vaporization of sulfur trioxide from oleum spills depends not just on its partial pressure, but a variety of conditions. Complex chemical reaction and heat generation that occur in the liquid phase determine the amount of sulfur trioxide released above a pool of liquid. The sulfur trioxide or CSA vapors then react instantaneously with the moisture in the atmosphere generating sulfuric acid and/or HCl and heat. Water and/or foam are used effectively in mitigating oleum and CSA spills. However, very limited laboratory or field data are currently available that describe the complex behavior of these chemicals. Several theoretical models have been developed to predict the vaporization and dispersion of the chemical upon loss of containment. These models and methods have not been validated. In this article, details are provided on field tests conducted in Nevada in 2003 and 2006 for spills of 65% oleum and CSA. A description of the spill mitigation, field measurement methods, and some preliminary results are included. © 2008 American Institute of Chemical Engineers Process Saf Prog, 2008
Local stray fields and magnetization reversal process of the FePrB sintered magnets
Authors: Sazonov S. N.
Published: March 2008

The Erratum contains minor technical corrections on pages 3827 and 3829 of the article by S. N. Sazonov [phys. stat. sol. (a) 203, 3824 (2006)]. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Liquid phase epitaxy of GaN on MOCVD GaN/sapphire and HVPE free‐standing substrates under high nitrogen pressure
Authors: Bockowski M. , Strak P. , Kempisty P. , Grzegory I. , Lucznik B. , Krukowski S. , Porowski S.
Published: March 2008

Results of liquid phase epitaxy of GaN on MOCVD sapphire/GaN and HVPE free‐standing GaN substrates by high pressure solution method are presented. The finite element calculation using experimentally measured temperatures is used for modeling the convective transport in the liquid gallium. The influence of a baffle and thermal conductivity of the various seeds for convection in liquid metal is analyzed in details. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth of single crystalline GaN from chlorine‐free gas phase
Authors: Rost H.‐J. , Siche D. , Böttcher K. , Gogova D. , Fornari R.
Published: March 2008

This work is focused on the development of GaN bulk growth to overcome some limits of the established HVPE method. Evaporated Ga is transported by a carrier gas to the substrate where it reacts with atomic nitrogen from the ammonia decomposition to form GaN at temperatures of 1000–1200°C and pressures of 200–800 hPa. To prove the methods potential, 1 mm thick polycrystalline layers were deposited on the substrate holder with rates up to 50 µmh‐1. Numerical simulations of temperature‐, flow‐ and concentration field of the gas species were used to optimize crucible geometry and growth regime. It was experimentally found that in addition to temperature, total pressure and ammonia flow other parameters like source composition; crucible material and flow conditions near the substrate may affect seeding, growth rate and layer quality. First epitaxial layers up to 280 µm thickness were successfully grown on different bulk and template substrates. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ultra‐thin InGaN photodetectors for standing wave interferometry
Authors: Hauguth‐Frank S. , Lebedev V. , Büchner H.‐J. , Jäger G. , Ambacher O.
Published: March 2008

In this work, we report on the fabrication as well as on the structural and optoelectronical characterisation of ultra‐thin In‐rich InxGa1–xN (0.56 < x < 1) metal‐semiconductor‐metal photodetectors designed for standing wave intensity profile measurements at the wavelength of He‐Ne laser. In particular, In0.64Ga0.36N/GaN structures have shown a short time response close to the RC time constant of ∼0.6 μs at low fields, with transparency of more than 77%. Structural analysis of InB0.64BGaB0.36BN layer showed no phase separation phenomena. However, a large biaxial strain and a gradient in the In content along the c‐axis have been observed driven by enormous biaxial strain in the heterostructure. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
MOVPE growth and investigation of AlInN/AlN multiple quantum wells
Authors: Mauder C. , Khoshroo L. Rahimzadeh , Rzheutski M. V. , Lutsenko E. V. , Yablonskii G. , Kozlovsky V. I. , Woitok J. , Dikme Y. , Heuken M. , Kalisch H. , Jansen R. H.
Published: March 2008

We report about the MOVPE growth and characterisation of Al0.90In0.10N single layers and multiple quantum well structures (MQW) containing 8 periods of Al0.90In0.10N/AlN quantum wells. All samples show good quality in high‐resolution X‐ray diffractometry (HRXRD) evaluation, superlattice fringes up to the 2nd order can be seen for the MQW sample. In optical transmission experiments, an absorption edge for the Al0.90In0.10N single layer is detected at 4.9 eV. Due to the low intensity of emission and limited sensitivity of our setup in this spectral region, photoluminescence (PL) emission above 4 eV is only visible for the MQW sample. Both PL and cathodoluminescence (CL) measurements show an emission peak at longer wavelength for the Al0.90In0.10N/AlN MQW sample. When increasing the excitation current density in CL, the emission at lower wavelength is clearly enhanced, while it is slightly reduced at higher wavelength. We believe this to be a saturation effect of a defect‐related emission. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
GaN/AlN free‐standing nanowires grown by molecular beam epitaxy
Authors: Tchernycheva M. , Sartel C. , Cirlin G. , Travers L. , Patriarche G. , Largeau L. , Mauguin O. , Harmand J.‐C. , Dang Le Si , Renard J. , Gayral B. , Nevou L. , Julien F.
Published: March 2008

We report on the growth, structural and optical properties of GaN/AlN free standing NWs. The NW lateral growth rate was investigated using thin AlN marker layers. The lateral growth is found to be homogeneous along the NW axis. Its rate can be tuned from ∼1% to ∼10% of the axial growth rate by changing III/V flux ratio. The resulting axial and lateral heterostructures were studied by micro‐photoluminescence and micro‐cathodoluminescence, which revealed sharp (several meV broad) emission lines. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Band gap and effective electron mass of cubic InN
Authors: Schley P. , Napierala C. , Goldhahn R. , Gobsch G. , Schörmann J. , As D. J. , Lischka K. , Feneberg M. , Thonke K. , Fuchs F. , Bechstedt F.
Published: March 2008

We succeeded in growing single crystalline c‐InN films on 3C‐SiC substrate with a c‐GaN buffer layer by MBE. Spectroscopic ellipsometry is applied in order to determine the complex dielectric function for cubic InN from mid‐infrared into the visible spectral region. The high electron densities above 1019 cm–3 cause pronounced Burstein‐Moss shifts at the gap. Taking into account the non‐parabolicity and the filling of the conduction band, data analysis yields renormalized band edges between 0.430 and 0.455 eV. Including carrier‐induced band‐gap renormalization we estimate a zero‐density band gap of ∼0.596eV for c‐InNwith a corresponding effective electron mass of 0.041m0 at the Γ point of the Brillouin zone. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The chemical ecology of crucifers and their fungal pathogens: Boosting plant defenses and inhibiting pathogen invasion
Authors: Pedras M. Soledade C.
Published: March 2008

Fungal plant diseases can cause very substantial yield losses in crucifer crops such as rapeseed and canola, or vegetables such as cabbage and broccoli. To devise sustainable methods to prevent and deter crucifer pathogens, the chemical interaction between crucifers and their fungi is under intense investigation. Crucifers produce complex blends of secondary metabolites with diverse ecological roles that include protection against microbial pathogens and other pests. The secondary metabolites involved in crucifer defense, namely phytoalexins and phytoanticipins, and their metabolism by fungal pathogens indicate that some fungi produce different enzymes to detoxify these metabolites and that some fungal detoxifying enzymes are rather specific. Chemical synthesis and screening of phytoalexin analogue libraries using cultures of fungal pathogens, as well as protein extracts, have shown that such detoxification reactions can be inhibited and that some inhibitors are strongly antifungal. Overall results of current work show the feasibility of using selective inhibitors of fungal detoxifying enzymes, i.e., paldoxins, to protect plants by boosting their chemical defenses. © 2008 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 8: 109–115; 2008: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20140
XRF analysis of chromite‐rich samples—another look at powder briquettes
Authors: Merkle R. K. W. , Sunder Raju P. V. , Loubser M.
Published: March 2008

Chromite‐rich samples are notoriously difficult to analyze by XRF spectrometry because of the low solubility of chromium in lithium borate fluxes. Our evaluation of the suitability to use powder briquettes of micronized samples implies that reasonable results can be obtained, but critical awareness of the questions behind the analyses and the possible shortcomings of data reduction procedures are required. Copyright © 2008 John Wiley & Sons, Ltd.
Spectroscopic evidence for the existence of an obligate pre‐fibrillar oligomer during glucagon fibrillation
Authors: Christensen Peter Astrup , Pedersen Jesper Søndergaard , Christiansen Gunna , Otzen Daniel Erik
Published: March 2008

The 29‐residue peptide hormone glucagon has been used as a model system for the study of amyloid‐like fibrils. Atomic force microscopy (AFM) studies have detected putative oligomeric species during this lag phase, but this has not been confirmed by any spectroscopic technique. Here we use an attached pyrene group to detect association (excimer formation) between individual glucagon molecules. Our data show that excimer formation precedes fibrillation both at different pHs and with sulfate, and support our original proposal that glucagon fibril formation is preceded by oligomer formation. We suggest that pyrene‐labelling may be a useful way to monitor oligomer formation during protein fibrillation.
The Head Nurse
Authors: Walker Marion
Published: March 2008

THE HEAD NURSE by Jean Barrett, 397 pages, New York, Appleton‐Century‐Crofts, Division of Meredith Publishing Company, 1962. Price: $4.95.
Fractures & Orthopedic Surgery for Nurses & Physiotherapists
Authors: Skalitzky Barbara
Published: March 2008

Arthur Naybr Ch.M., M.B., MSc. (Shef.), F.R.C.S. (Eng.), F.R.C.S. (Edin.), FRACTURES & ORTHOPEDIC SURGERY FOR NURSES & PHYSIOTHERAPISTS, Fifth Edition, 1964, The Williams and Wilkins Company, Baltimore, 362 pages, Price $6.50.
The Operattng Room Techntcian
Authors: Metzger Ruth
Published: March 2008

Sister Mary Louise C.C., R.N., B.S.N. Ed., The Operattng Room Techntcian, 1965, The C. V. Mosby Co., St. Louis, 275 pages. $6.85.
Emergency and Disaster Nursing
Authors: Tighe Isabella
Published: March 2008

Robert F. Mahoney, Emergency And Disaster Nursing, 1965, the Macmillan Company, New York, 228 pages, Price $4.95.
Historical and Experimental Approaches to Modern Resuscitation
Authors: Rogers Caroline
Published: March 2008

John W. Pearson B.M. (Oxon.), Historical And Experimental Approaches to Modern Resuscitation, 1965, Charles C. Thomas, Springfield, Illinois, 106 pages, Price $6.50
Reconstruction Surgery and Traumatology
Authors: O'Keefe Margaret
Published: March 2008

Reconstruction Surgery and Traumatology, Vol. 10 by E. Morscher, M.D., S. Karger, Basel, Switzerland, 104 pages. Price $9.35.
Psychiatric Complications of Heart Transplants
Authors: Lunde Donald T.
Published: March 2008

As the psychiatric consultant to a cardiac transplant team, this author faced a unique challenge. He discusses the factors involved in the psychiatric screening of potential candidates for the operation and describes the preoperative and postoperative psychiatric complications observed among nine patients who have received heart transplants at his medical center. As surgery progresses in the direction of organ replacement, he concludes, psychiatrists must prepare to meet the increasing need for their services in this area.
The Patient in Surgery: A Guide for Nurses
Authors: Slavens Myra Kay
Published: March 2008

THE PATIENT IN SURGERY: A GUIDE FOR NURSES George D. LeMaitre, M.D., and Janet A. Finnegan, R.N., M.S., 399 pages, Philadelphia and London, W. B. Saunders Company, 1965. Price $4.95.
Report from Headquarters
Authors: Bales John K.
Published: March 2008

In this, the first of a two‐part report, AORN's new Executive Director tells briefly of his background and explains what brought him to AORN. In the December JOURNAL, Mr. Bales will explain how he has reorganized National Headquarters in order to accomplish the short and long‐range goals being developed now for AORN.
Quality of life of Turkish patients with depression in Ankara and in Berlin
Authors: Iren Akbiyik D. , Berksun O.E. , Sumbuloglu V. , Sentürk V. , Priebe S.
Published: March 2008

Background and Objectives

Quality of life (QOL) of immigrant groups with mental disorders should be compared with similar patients in the country of origin. Therefore, this study evaluated the QOL in Turkish patients who were in treatment because of depressive disorders in Ankara and Berlin.

Subjects and Methods

Patients with depressive disorders were recruited from services in Ankara and Berlin. The same researcher interviewed all patients and assessed socio-demographic characteristics, symptomatology, psychiatric diagnosis and QOL.

Results

QOL of patients in Ankara was significantly higher than that of patients in Berlin. Satisfaction with specific life domains also showed significant differences between the two groups. Factors positively associated with QoL in Berlin were marital status, shorter duration of marriage, fewer occupants per household, a relaxed religious attitude, being informed about the illness by the physician, and lower levels of symptoms. In Ankara, only initial help seeking behavior and level of depressive symptoms were associated with QOL.

Conclusion

QOL of Turkish patients with depression in Berlin appears lower than that of similar patients in Ankara. Different factors may influence QOL of Turkish patients with depression living in the place of origin and having emigrated to Germany.
Mental health, health care utilisation of migrants in Europe
Authors: Lindert J. , Schouler-Ocak M. , Heinz A. , Priebe S.
Published: March 2008

Background

Migration during the 1990s has been high and has been characterised by new migrations. Migration has been a key force in the demographic changes of the European population. Due to the different condition of migration in Europe, variables related to mental health of migrants are: motivation for migration, living conditions in the home and in the host country.

Aims

To give an overview on (i) prevalence of mental disorders; suicide; alcohol and drug abuse; (ii) access to mental health and psychosocial care facilities of migrants in the European region, and (iii) utilisation of health and psychosocial institution of these migrants.

Methods

Non-system review of the literature concerning mental health disorders of migrants and their access to and their consumption of health care and psychosocial services in Europe.

Results

It is impossible to consider “migrants” as a homogeneous group concerning the risk for mental illness. The literature showed (i) mental health differs between migrant groups, (ii) access to psychosocial care facilities is influenced by the legal frame of the host country; (iii) mental health and consumption of care facilities is shaped by migrants used patterns of help-seeking and by the legal frame of the host country.

Conclusion

Data on migrant's mental health is scarce. Longitudinal studies are needed to describe mental health adjusting for life conditions in Europe to identify those factors which imply an increased risk of psychiatric disorders and influence help seeking for psychosocial care. In many European countries migrants fall outside the existing health and social services, particularly asylum seekers and undocumented immigrants.
Working with the cultural formulation in therapy
Authors: Borra R.
Published: March 2008

The Cultural Formulation of Diagnosis, put away in the Appendix IX in the DSM-IV, was developed during the preparation of the DSMIV by the NIMH group Culture and Diagnosis, a group of international cultural experts to make the manual more culturally sensitive. The Cultural Formulation supplements the nomothetic or standardized diagnostic ratings of the DSM with an ideographic statement, emphasizing the patient's personal experience and the corresponding cultural reference group(s). In the Netherlands the Cultural Formulation proved to be a very useful and innovative instrument to make the diagnostic process and treatment more culturally sensitive. Aim of this article is to give more publicity to this model also in the rest of Europe.
Temporal variation of non-ideal plumes with sudden reductions in buoyancy flux
Authors: SCASE M. M. , CAULFIELD C. P. , DALZIEL S. B.
Published: March 2008

We model the behaviour of isolated sources of finite radius and volume flux which experience a sudden drop in buoyancy flux, generalizing the previous theory presented in Scase et al. (J. Fluid Mech., vol. 563, 2006, p. 443). In particular, we consider the problem of the source of an established plume suddenly increasing in area to provide a much wider plume source. Our calculations predict that, while our model remains applicable, the plume never fully pinches off into individual rising thermals.

We report the results of a large number of experiments, which provide an ensemble to compare to theoretical predictions. We find that provided the source conditions are weakened in such a way that the well-known entrainment assumption remains valid, the established plume is not observed to pinch off into individual thermals. Further, not only is pinch-off not observed in the ensemble of experiments, it cannot be observed in any of the individual experiments. We consider both the temporal evolution of the plume profile and a concentration of passive tracer, and show that our model predictions compare well with our experimental observations.
Absolute instability in axisymmetric wakes: compressible and density variation effects
Authors: MELIGA PHILIPPE , SIPP DENIS , CHOMAZ JEAN-MARC
Published: March 2008

Lesshafft & Huerre (Phys. Fluids, 2007; vol. 19, 024102) have recently studied the transition from convective to absolute instability in hot round jets, for which absolute instability is led by axisymmetric perturbations and enhanced when lowering the jet density. The present paper analyses similarly the counterpart problem of wake flows, and establishes that absolute instability is then led by a large-scale helical wake mode favoured when the wake is denser than the surrounding fluid. This generalizes to variable density and compressible wakes the results of Monkewitz (J. Fluid Mech. vol 192, 1988, p. 561). Furthermore, we show that in a particular range of density ratios, the large-scale helical wake mode can become absolutely unstable by increasing only the Mach number up to high subsonic values. This possibility of an absolute instability triggered by an increase of the Mach number is opposite to the behaviour previously described in shear flows such as plane mixing layers and axisymmetric jets. A physical interpretation based on the action of the baroclinic torque is proposed. An axisymmetric short-scale mode, similar to that observed in plane mixing layers, leads the transition in light wakes, but the corresponding configurations require large counterflow for the instability to be absolute.

These results suggest that the low-frequency oscillation present in afterbody wakes may be due to a nonlinear global mode triggered by a local absolute instability, since the azimuthal wavenumber and absolute frequency of the helical wake mode agree qualitatively with observations.
Lateral dispersion in random cylinder arrays at high Reynolds number
Authors: TANINO YUKIE , NEPF HEIDI M.
Published: March 2008

Laser-induced fluorescence was used to measure the lateral dispersion of passive solute in random arrays of rigid, emergent cylinders of solid volume fraction φ=0.010–0.35. Such densities correspond to those observed in aquatic plant canopies and complement those in packed beds of spheres, where φ≥0.5. This paper focuses on pore Reynolds numbers greater thanRes=250, for which our laboratory experiments demonstrate that the spatially averaged turbulence intensity andKyy/(Upd), the lateral dispersion coefficient normalized by the mean velocity in the fluid volume,Up, and the cylinder diameter,d, are independent ofRes. First,Kyy/(Upd) increases rapidly with φ from φ =0 to φ=0.031. Then,Kyy/(Upd) decreases from φ=0.031 to φ=0.20. Finally,Kyy/(Upd) increases again, more gradually, from φ=0.20 to φ=0.35. These observations are accurately described by the linear superposition of the proposed model of turbulent diffusion and existing models of dispersion due to the spatially heterogeneous velocity field that arises from the presence of the cylinders. The contribution from turbulent diffusion scales with the mean turbulence intensity, the characteristic length scale of turbulent mixing and the effective porosity. From a balance between the production of turbulent kinetic energy by the cylinder wakes and its viscous dissipation, the mean turbulence intensity for a given cylinder diameter and cylinder density is predicted to be a function of the form drag coefficient and the integral length scalelt. We propose and experimentally verify thatlt=min{d, 〈sn〉A}, where 〈sn〉Ais the average surface-to-surface distance between a cylinder in the array and its nearest neighbour. We farther propose that only turbulent eddies with mixing length scale greater thandcontribute significantly to net lateral dispersion, and that neighbouring cylinder centres must be farther thanr* from each other for the pore space between them to contain such eddies. If the integral length scale and the length scale for mixing are equal, thenr*=2d. Our laboratory data agree well with predictions based on this definition ofr*.
Stability limits of unsteady open capillary channel flow
Authors: GRAH ALEKSANDER , HAAKE DENNIS , ROSENDAHL UWE , KLATTE JÖRG , DREYER MICHAEL E.
Published: March 2008

This paper is concerned with steady and unsteady flow rate limitations in open capillary channels under low-gravity conditions. Capillary channels are widely used in Space technology for liquid transportation and positioning, e.g. in fuel tanks and life support systems. The channel observed in this work consists of two parallel plates bounded by free liquid surfaces along the open sides. The capillary forces of the free surfaces prevent leaking of the liquid and gas ingestion into the flow.

In the case of steady stable flow the capillary pressure balances the differential pressure between the liquid and the surrounding constant-pressure gas phase. Increasing the flow rate in small steps causes a decrease of the liquid pressure. A maximum steady flow rate is achieved when the flow rate exceeds a certain limit leading to a collapse of the free surfaces due to the choking effect. In the case of unsteady flow additional dynamic effects take place due to flow rate transition and liquid acceleration. The maximum flow rate is smaller than in the case of steady flow. On the other hand, the choking effect does not necessarily cause surface collapse and stable temporarily choked flow is possible under certain circumstances.

To determine the limiting volumetric flow rate and stable flow dynamic properties, a new stability theory for both steady and unsteady flow is introduced. Subcritical and supercritical (choked) flow regimes are defined. Stability criteria are formulated for each flow type. The steady (subcritical) criterion corresponds to the speed index defined by the limiting longitudinal small-amplitude wave speed, similar to the Mach number. The unsteady (supercritical) criterion for choked flow is defined by a new characteristic number, the dynamic index. It is based on pressure balances and reaches unity at the stability limit.

The unsteady model based on the Bernoulli equation and the mass balance equation is solved numerically for perfectly wetting incompressible liquids. The unsteady model and the stability theory are verified by comparison to results of a sounding rocket experiment (TEXUS 41) on capillary channel flows launched in December 2005 from ESRANGE in north Sweden. For a clear overview of subcritical, supercritical, and unstable flow, parametric studies and stability diagrams are shown and compared to experimental observations.
Onset of wall-attached convection in a rotating fluid layer in the presence of a vertical magnetic field
Authors: SÁNCHEZ-ÁLVAREZ J. J. , DEL ARCO E. CRESPO , BUSSE F. H.
Published: March 2008

A horizontal fluid layer heated from below and rotating about a vertical axis in the presence of a vertical magnetic field is considered. From earlier work it is known that the onset of convection in a rotating layer usually occurs in the form of travelling waves attached to the vertical sidewalls of the layer. It is found that this behaviour persists when a vertical magnetic field is applied. When the Elsasser number Λ is kept constant and the sidewall is thermally insulating the critical Rayleigh number Rc increases in proportion to the rotation rate described by the square root of the Taylor number, τ. This asymptotic relationship is found for an electrically highly conducting sidewall as well as for an electrically insulating one. At fixed rotation rate for Q≫τ, Rc grows in proportion to Q when the sidewall is electrically highly conducting, and in proportion to Q3/4 when the sidewall is electrically insulating. Here Q is the Chandrasekhar number which is a measure of the magnetic energy density, and a thermally insulating sidewall has been assumed. Of particular interest is the possibility that the magnetic field counteracts the stabilizing influence of rotation on the onset of sidewall convection in the case of thermally insulating sidewalls. When the sidewall is thermally highly conducting, Rc for the sidewall mode grows in proportion to τ4/3. This asymptotic behaviour is found for both cases of electrical boundary conditions, but it no longer precedes the onset of bulk convection for Λ ≳ 1.
Mental–physical co-morbidity and its relationship with disability: results from the World Mental Health Surveys
Authors: Scott K. M. , Von Korff M. , Alonso J. , Angermeyer M. C. , Bromet E. , Fayyad J. , de Girolamo G. , Demyttenaere K. , Gasquet I. , Gureje O. , Haro J. M. , He Y. , Kessler R. C. , Levinson D. , Medina Mora M. E. , Oakley Browne M. , Ormel J. , Posada-Villa J. , Watanabe M. , Williams D.
Published: March 2008

Background

The relationship between mental and physical disorders is well established, but there is less consensus as to the nature of their joint association with disability, in part because additive and interactive models of co-morbidity have not always been clearly differentiated in prior research.

Method

Eighteen general population surveys were carried out among adults as part of the World Mental Health (WMH) Survey Initiative (n=42 697). DSM-IV disorders were assessed using face-to-face interviews with the Composite International Diagnostic Interview (CIDI 3.0). Chronic physical conditions (arthritis, heart disease, respiratory disease, chronic back/neck pain, chronic headache, and diabetes) were ascertained using a standard checklist. Severe disability was defined as on or above the 90th percentile of the WMH version of the World Health Organization Disability Assessment Schedule (WHODAS-II).

Results

The odds of severe disability among those with both mental disorder and each of the physical conditions (with the exception of heart disease) were significantly greater than the sum of the odds of the single conditions. The evidence for synergy was model dependent: it was observed in the additive interaction models but not in models assessing multiplicative interactions. Mental disorders were more likely to be associated with severe disability than were the chronic physical conditions.

Conclusions

This first cross-national study of the joint effect of mental and physical conditions on the probability of severe disability finds that co-morbidity exerts modest synergistic effects. Clinicians need to accord both mental and physical conditions equal priority, in order for co-morbidity to be adequately managed and disability reduced.
The prevalence of premenstrual dysphoric disorder in a randomly selected group of urban and rural women
Authors: Gehlert S. , Song I. H. , Chang C.-H. , Hartlage S. A.
Published: March 2008

Background

Premenstrual dysphoric disorder (PMDD) was included as a provisional diagnostic category in the appendices of Diagnostic and Statistical Manual of Mental Disorders (DSM)-III-R (then called late luteal phase dysphoric disorder) and remained as an appendix in DSM-IV. Our study aimed to determine the prevalence of PMDD using all four DSM-IV research diagnostic criteria in a representative sample of women of reproductive age in the United States.

Method

Data were collected in the homes of women between the ages of 13 and 55 years in two urban and two rural sites using a random sampling procedure developed by the National Opinion Research Center. Women completed daily symptom questionnaires and provided urine specimens each day for two consecutive ovulatory menstrual cycles (ovulation was estimated for women taking oral contraceptives) and were screened for psychiatric disorders by trained interviewers. Symptoms were counted toward a diagnosis of PMDD if they worsened significantly during the late luteal week during two consecutive ovulatory menstrual cycles, occurred on days in which women reported marked interference with functioning, and were not due to another mental disorder.

Results

In the final analysis, 1246 women who had had at least one menstrual cycle and were neither naturally nor surgically menopausal nor pregnant were selected. Of the women in the study, 1.3% met criteria for the diagnosis as defined in DSM-IV.

Conclusions

The prevalence of PMDD is considerably lower than DSM-IV estimates and all but one of the estimates obtained from previous studies when all DSM-IV diagnostic criteria are considered. We suggest a new process for diagnosing PMDD based on our findings.
Students' assessments of music learning experiences from kindergarten to university
Authors: Ruismäki Heikki , Tereska Tarja
Published: March 2008

This article reports on a retrospective study of Finnish pre-service elementary teachers' assessments of their musical experiences in nursery school and elementary and secondary school and real-time study of their experiences in teacher training. The participants (N = 590) had received musical instruction in five age groups (4–6 years, 7–12 years, 13–15 years, 16–19 years, 20–25 years). The assessments were most positive in the 4–6 years group and thereafter declined until puberty in the 13–15 years group. A change in a positive direction was perceived in the 16–19 years group and also in the 20–25 years group (during teacher training). Gender differences were statistically significant except during upper secondary school. The most enjoyable activities in formal music education were singing and playing; music theory was experienced most negatively.
The impact of educators' skills and training on the delivery of music in the learning area Arts and Culture within two districts of the Gauteng province of South Africa
Authors: Klopper Christopher
Published: March 2008

This article is the documentation of a sub-research question of a larger empirical study that employed quantitative methods to identify variables that are impacting on the delivery of music in the learning area Arts and Culture in South Africa extrapolated from questionnaires. Analysis of the data revealed that educators lack specialisation in music and have limited training in any of the art forms. Significant relationships were established between the educator and involvement in music activities within and outside of the school environment.
Gas hydrate dissociation in sediments: Pressure‐temperature evolution
Authors: Kwon Tae‐Hyuk , Cho Gye‐Chun , Santamarina J. Carlos
Published: March 2008

Hydrate‐bearing sediments may destabilize spontaneously as part of geological processes, unavoidably during petroleum drilling/production operations or intentionally as part of gas extraction from the hydrate itself. In all cases, high pore fluid pressure generation is anticipated during hydrate dissociation. A comprehensive formulation is derived for the prediction of fluid pressure evolution in hydrate‐bearing sediments subjected to thermal stimulation without mass transfer. The formulation considers pressure‐ and temperature‐dependent volume changes in all phases, effective stress‐controlled sediment compressibility, capillarity, and the relative solubilities of fluids. Salient implications are explored through parametric studies. The model properly reproduces experimental data, including the PT evolution along the phase boundary during dissociation and the effect of capillarity. Pore fluid pressure generation is proportional to the initial hydrate fraction and the sediment bulk stiffness; is inversely proportional to the initial gas fraction and gas solubility; and is limited by changes in effective stress that cause the failure of the sediment. When the sediment stiffness is high, the generated pore pressure reflects thermal and pressure changes in water, hydrate, and mineral densities. Comparative analyses for CO2 and CH4 highlight the role of gas solubility in excess pore fluid pressure generation. Dissociation in small pores experiences melting point depression due to changes in water activity, and lower pore fluid pressure generation due to the higher gas pressure in small gas bubbles. Capillarity effects may be disregarded in silts and sands, when hydrates are present in nodules and lenses and when the sediment experiences hydraulic fracture.
Spectral properties of acoustic gravity wave turbulence
Authors: Shaikh Dastgeer , Shukla Padma K. , Stenflo Lennart
Published: March 2008

The nonlinear turbulent interactions between acoustic gravity waves are investigated using two‐dimensional nonlinear fluid simulations. The acoustic gravity waves consist of velocity and density perturbations and propagate across the density gradients in the vertical direction in the Earth's atmosphere. We find that the coupled two component model exhibits generation of large‐scale velocity potential flows along the vertical direction, while the density perturbations relax toward an isotropic random distribution. The characteristic turbulent spectrum associated with the system has a Kolmogorov‐like feature and tends to relax toward a k−5/3 spectrum, where k is a typical wave number. The cross field diffusion associated with the velocity potential grows linearly and saturates in the nonlinear phase.
Spatial and temporal variation of rainfall over New Zealand
Authors: Sansom John , Thompson Craig S.
Published: March 2008

A hidden semi‐Markov model (HSMM) was applied to high temporal resolution rain rate data, and, after determining a transition structure for all of New Zealand, the model's parameters from fits at about 90 sites were mapped. The addition of bogus sites was required before a verification gave an acceptable result for some annual statistics over a 0.1° by 0.1° (i.e., about 10 km) spaced grid. Synthetic rainfall series were generated at each of the grid points, and various aspects of rainfall climatology were mapped. The rainfall process can be viewed as a succession of precipitation events which individually break down into a succession of episodes of either rain type precipitation (i.e., large spatial scale and persistent) or shower type precipitation (i.e., small‐scale and short lived). The synthetic data sets showed that most rainfall events consist of a single shower and the rest rarely consist of more than two interchanges between rain and showers. These interchanges take place between periods of rain and showers centered at the higher end of the range of rain rates, and the transition from rain to showers is about three times more likely than that from showers to rain. The area with the highest probabilities for these transitions is the Southern Alps in the west of the South Island of New Zealand.
Salinity of the Eocene Arctic Ocean from oxygen isotope analysis of fish bone carbonate
Authors: Waddell Lindsey M. , Moore Theodore C.
Published: March 2008

Stable isotope analysis was performed on the structural carbonate of fish bone apatite from early and early middle Eocene samples (∼55 to ∼45 Ma) recently recovered from the Lomonosov Ridge by Integrated Ocean Drilling Program Expedition 302 (the Arctic Coring Expedition). Theδ18O values of the Eocene samples ranged from −6.84‰ to −2.96‰ Vienna Peedee belemnite, with a mean value of −4.89‰, compared to 2.77‰ for a Miocene sample in the overlying section. An average salinity of 21 to 25‰ was calculated for the Eocene Arctic, compared to 35‰ for the Miocene, with lower salinities during the Paleocene Eocene thermal maximum, theAzollaevent at ∼48.7 Ma, and a third previously unidentified event at ∼47.6 Ma. At theAzollaevent, where the organic carbon content of the sediment reaches a maximum, a positiveδ13C excursion was observed, indicating unusually high productivity in the surface waters.
Cyclicity in the middle Eocene central Arctic Ocean sediment record: Orbital forcing and environmental response
Authors: Sangiorgi Francesca , van Soelen Els E. , Spofforth David J. A. , Pälike Heiko , Stickley Catherine E. , St. John Kristen , Koç Nalan , Schouten Stefan , Sinninghe Damsté Jaap S. , Brinkhuis Henk
Published: March 2008

Continuous X‐ray fluorescence scanning of middle Eocene (∼46 Ma) core M0002A‐55X (∼236–241 m composite depth), recovered during Integrated Ocean Drilling Program Expedition 302, revealed a strong cyclical signal in some major and trace geochemical elements. We performed a multiproxy study of the same core, which included organic geochemical, sedimentological, and biological parameters, and integrated our results with available geochemical and physical properties data. The target was to look for cyclicity in the several proxies, investigate their frequency, and understand the environmental response to the potential forcing. Results indicate that a higher terrigenous component corresponds to lower organic carbon concentration, smaller contributions by angiosperm pollen and spores, organic‐walled dinoflagellate cysts, and chrysophyte cysts (lower productivity, shorter growing season for flowering plants, and lower stratification) but higher contributions by bisaccate pollen and diatoms (drier conditions on land, more marine conditions) and higher terrigenous sand (ice‐rafted debris (IRD)). Our investigation shows that physical proxy parameters hold cyclicity with periods of about 50 and 100 cm and that these frequency components are compatible with a Milankovitch‐type orbital forcing, representing precession and obliquity, respectively. The longer 100 cm cyclicity is also present in the biological (pollen, dinoflagellate cysts, and siliceous microfossils) and in the sedimentological (IRD) proxies. The environmental signal derived from the integrated multiproxy analysis suggests that in an enclosed Arctic Ocean at time of ice (sea ice and glacial ice) initiation the biological proxies responded more strongly to growing season length/darkness, whereas the terrigenous components, directly driven by sea ice and/or glacial ice formation and extent, responded more directly to seasonal insolation.