bluuebunny/crossref_metadata_2025 huggingface dataset:
Minority recruitment into the genetic counseling profession
Authors: Smith Stephanie C. , Warren Nancy Steinberg , Misra Lavanya
Published: January 2005

In the past, genetic counseling training programs have had an abundance of applicants for the number of slots available. They have, however, had a very limited pool of minority applicants. At the June 1992 meeting of the genetic counseling training programs directors the topic of minority recruitment was explored. The resources and recommendations that resulted from this discussion can be used by other medical training programs.
Amniocentesis in sociocultural perspective
Authors: Rapp Rayna
Published: January 2005

This article reports on an anthropological investigation of the social impact and cultural meaning of amniocentesis conducted in New York City, illustrating how class differences, as well as sociocultural diversity, deeply affect pregnant women's acceptance, rejection, and interpretation of prenatal testing. The article also suggests the importance of recognizing how counselors' cultural backgrounds and styles affect patient‐counselor communications.
Implications of human genome research: Impact on graduate education in genetic counseling
Authors: Biesecker Barbara Bowles , Vockley Catherine Walsh , Conover Elizabeth
Published: January 2005

A conference of genetic counseling and clinical nurse specialist graduate program directors was hosted by the National Society of Genetic Counselors and funded by the Ethical, Legal, and Social Implications Program of the National Center for Human Genome Research in June 1992. One aspect of the conference addressed implications of the Human Genome Initiative for graduate education in genetic counseling. Within this paper, the topics of human variation and diversity, genetic discrimination, issues in non‐directiveness, and genetic screening and policy development are reviewed and recommendations made for graduate curricula development and enhancement. In addition, suggestions are included for practicing genetic counselors.
Chlorhexidine Gluconate: An Ideal Scolicidal Agent in the Treatment of Intraperitoneal Hydatidosis?
Authors: Puryan Kenan , Karadayi Kursat , Topcu Omer , Canbay Emel , Sumer Zeynep , Turan Mustafa , Karayalcin Kaan , Sen Metin
Published: January 2005

Hydatid disease is a parasitic disease that is treated primarily by surgery. The most important complication of surgical treatment is spillage of the contents of the cyst, leading to secondary dissemination. In this study, the effect of chlorhexidine gluconate (Chx‐Glu) was investigated in the treatment of experimental intraperitoneal hydatidosis (IPH). IPH was reproduced in 100 Wistar albino rats by inoculation with 1 ml of a suspension contained approximately 1500 viable protoscolices of Echinococcus granulosus following determination of scolicidal activity of chlorhexidine gluconate in vitro. Five minutes after protoscolex inoculation, 5 ml of the scolicidal solution was instilled into the peritoneal cavity: 0.9% NaCl (control group), 4.0% Chx‐Glu, 0.4% Chx‐Glu, and 0.04% Chx‐Glu. After 6 months of follow‐up, the rats were sacrificed, and the number of isolated cysts, peroperative and postoperative deaths, and toxicity were evaluated. Cyst formation did not occur in any of the Chx‐Glu groups compared to the control group (p < 0.05), whereas it was detected in all of the control rats. In addition, to 4.0% Chx‐Glu was found to be more toxic and to cause a high mortality rate compared to the 0.4% and 0.04% Chx‐Glu groups and the control group (p < 0.05). Chx‐Glu 0.04% was found to be the most potent, nontoxic agent; it is easily available, inexpensive, and highly potent in a short period of time at the low concentration. Chx‐Glu 0.04% can be used safely in the treatment of intraperitoneal hydatidosis and hydatid cyst.
Surgical Treatment of Hurthle Cell Tumors of the Thyroid
Authors: Chao Tzu‐Chieh , Lin Jen‐Der , Chen Miin‐Fu
Published: January 2005

Hurthle cell tumors are relatively rare thyroid tumors and their management and prognosis is controversial. We retrospectively review 135 Hurthle cell adenomas and 28 Hurthle cell carcinomas of the thyroid surgically treated at our institute. No significant difference was found between the adenoma and carcinoma groups in patient age, gender, and tumor size. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of fine‐needle aspiration cytology (FNAC) in detecting malignancy were 87.5%, 19.3%, 31.2%, 18.6%, and 88.0%. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of frozen section in detecting malignancy of the thyroid gland were 40.0%, 100.0%, 92.9%, 100.0%, and 92.0%. Most of the adenomas were treated with procedures no less invasive than lobectomy/isthmusectomy. Meanwhile, most of the carcinoma patients underwent total thyroidectomy. Operative morbidity occurred in six patients (3.8%), including transient recurrent laryngeal nerve palsy in three patients, damage to the external branch of the superior laryngeal nerve in two patients, and transient hypocalcemia in one patient. No recurrence of Hurthle cell adenomas was noted. Five adenoma patients died of causes unrelated to their Hurthle cell tumors, but no carcinoma patients died during the follow‐up period. In conclusion, clinical factors and FNAC are not helpful in the differentiation between adenoma and carcinoma. Unilateral Hurthle cell adenoma can be treated by lobectomy/isthmusectomy, and Hurthle cell carcinoma can be treated by total thyroidectomy with minimal operative morbidity.
Marlex Mesh Prefix Plug Hernioplasty Retrospective Analysis of 865 Operations
Authors: Pikoulis Emmanouil , Daskalakis Panayiotis , Psallidas Nicholaos , Karavokyros Ioannis , Stathoulopolos Athanasios , Godevenos Dimitrios , Leppaniemi Ari , Tsatsoulis Panayiotis
Published: January 2005

For 5 years (January 1998 to November 2002) our department has applied the Marlex Mesh Perfix Plug hernioplasty. This article demonstrates the experience gained in operative and postoperative aspects, costs, and outcome along with the results of a follow‐up analysis. Altogether, 801 patients (749 males, 52 females) were operated on Sixty‐four males had bilateral groin hernias, so the total number of hernioplasties amounted to 865. A total of 19 hernias were recurrent, 297 were direct, 545 were indirect or scrotal (or both) 21 were femoral, and 2 were Spigelian. Fifty‐three operations were performed on an emergency basis. Preoperative routine use of antibiotics was minimized throughout the years. Operating time fluctuated from 20 to 25 min (30‐40 minutes for recurrent hernias), and the postoperative hospital stay was 28 hours (6‐72) hours. The complication rate was 5% and the recurrence rate less than 1%. Early patient mobilization and return to everyday activities (1‐2 weeks) was encouraged. The follow‐up of 95% of the patient population lasted 12 to 60 months and was performed at 1 week, 1 month, 1 year, and yearly thereafter. The technique demonstrates less overall postoperative pain, discomfort, and complications combined with a remarkably low recurrence rate. The rapid rehabilitation with great patient comfort and decreased operating room time, resulting in lower financial costs, have led us nowadays to repair all types of inguinal hernias, femoral and recurrent ones, using this technique.
Microhabitat segregation in larvae of six species of coastal tiger beetles in Japan
Authors: Satoh Aya , Hori Michio
Published: January 2005

Two to four species of tiger beetles co‐occur in coastal habitats of Japan. We have already demonstrated that co‐occurring species exhibit interspecific size differences in adult mandible length, suggesting food resource partitioning with respect to prey size. In the present study, we investigated the larval microhabitats of six coastal species to examine whether spatial segregation occurs during the larval stage. The larvae of each species were found in specific microhabitats: Cicindelalewisii occurred at tidal flats, Abroscelis anchoralis at beaches, Chaetodera laetescripta at coastal dunes, and Lophyridia angulata at riverbanks in estuaries. Larvae of two congeners occurred in very different microhabitats: Callytron inspecularis at reed beds formed in tidal flats in estuaries and C. yuasai either in rock crevices, where the soil had built up, or at clay cliffs. These larval microhabitats differed among species in terms of vegetation cover, salinity, and soil texture. The larvae of four species (C. lewisii, A. anchoralis, C. inspecularis, and C. yuasai) were found at sites exposed to seawater, suggesting a tolerance to salinity. Additionally, we found differences in adult limb proportion among species. These differences seemed to be adapted to soil types in the larval microhabitats. Finally, we discuss the patterns of species assemblage of coastal tiger beetles in terms of habitat selection associated with microhabitat specificity during the larval stage and interspecific interaction associated with adult mandible size.
Calmodulin interacts with the cytoplasmic tails of the parathyroid hormone 1 receptor and a sub‐set of class b G‐protein coupled receptors
Authors: Mahon Matthew J. , Shimada Masako
Published: January 2005

Parathyroid hormone (PTH) binds to its receptor (PTH 1 receptor, PTH1R) and activates multiple pathways. The PTH1R, a class b GPCR, contains consensus calmodulin‐binding motifs. The PTH1R cytoplasmic tail interacts with calmodulin in a calcium‐dependent manner via the basic 1‐5‐8‐14 motif. Calcium‐dependent calmodulin interactions with the cytoplasmic tails of receptors for PTH 2, vasoactive intestinal peptide, pituitary adenylate cyclase activating peptide, corticotropin releasing hormone, calcitonin, and the glucagon‐like peptides 1 and 2 are demonstrated. The cytoplasmic tails of the secretin receptor and the growth hormone releasing hormone receptor either interact poorly or not at all with calmodulin, respectively. Fluphenazine, a calmodulin antagonist, enhances PTH‐mediated accumulation of total inositol phosphates, suggesting that calmodulin regulates signaling via phospholipase C.
Structural organization of the twin‐arginine translocation system in Streptomyces lividans
Authors: Keersmaeker Sophie De , Mellaert Lieve Van , Schaerlaekens Kristien , Dessel Wesley Van , Vrancken Kristof , Lammertyn Elke , Anné Jozef , Geukens Nick
Published: January 2005

The twin‐arginine translocation (Tat) system exports folded proteins across bacterial cytoplasmic membranes. Recently, genes encoding TatA, TatB and TatC homologues were identified in Streptomyces lividans and the functionality of the Tat pathway was demonstrated. Here, we have examined the localization and structural organization of the Tat components in S. lividans. Interestingly, besides being membrane‐associated proteins, S. lividans TatA and TatB were also detected in the cytoplasm. TatC could only be detected in isolated membrane fractions. Whereas all TatC was found to be stably inserted in the membrane, part of membrane‐associated TatA and TatB could be extracted following high salt, sodium carbonate or urea treatment suggesting a more loose association with the membrane. Finally, we have analyzed Tat complexes that could be purified from an S. lividans TatABC overproducing strain. From the cytoplasmic membrane, two types of high molecular mass Tat complexes could be isolated having a similar composition as those isolated from Escherichia coli. In the cytoplasm, TatA and TatB were detected as monomer or as homo‐oligomeric complexes.
Modulation of Alzheimer's pathology by cerebro‐ventricular grafting of hybridoma cells expressing antibodies against Aβ in vivo
Authors: Gaugler Meret N.M. , Tracy Jay , Kuhnle Katrin , Crameri Arames , Nitsch Roger M. , Mohajeri M. Hasan
Published: January 2005

Accumulation in brain of the β‐amyloid peptide (Aβ) is considered as crucial pathogenic event causing Alzheimer's disease (AD). Anti‐Aβ immune therapy is a powerful means for Aβ clearance from the brain. We recently showed that intravenous injections of anti‐Aβ antibodies led to reduction, elevation or no change in brain Aβ42 concentrations of an AD mouse model. We report here, in a second passive immunization protocol, a different bioactivity of same antibodies to alter brain Aβ42 concentrations. Comparing the bioactivity of anti‐Aβ antibodies in these two passive immunization paradigms underscores the potential of immune therapy for AD treatment and suggests that both the epitope recognized by the antibody and the mode of antibody administration are crucial for its biological activity.
Models for explaining the homeopathic healing process: a historical and critical account of principles central to homeopathy
Authors: Wilson J. , Guajardo G.
Published: January 2005

The success of Homeopathy in curing many diseases has been a serious challenge to science. Nineteenth century explanations for the healing process of Homeopathy cannot withstand the scrutiny of modern science and need to be abandoned or modified. The surviving propositions are discussed. A biocybernetic model with multilevels of electromagnetic feedback loops offers a hope of explaining the healing process. This model, its explanation of the healing process and experimental support are elaborated.
General practitioners and classical homeopaths treatment models for asthma and allergy
Authors: Rieper J. , Launsø L.
Published: January 2005

Complementary and alternative treatment (CAT) is increasingly popular with patients and health-care providers. In the western societies an increasing number of patients with asthma and allergy combine conventional and CAT. But health-care providers knowledge about the different treatment models applied within the conventional health care system and alternative treatment is generally poor. ‘Treatment model’ includes understanding of disease, diagnostic approach, treatment methods and expected effects of treatment. Different treatment models represent different social constructions of understanding. We present a conceptualization of general practitioners’ (GPs) and classic homeopaths’ (CHs) perceptions of their treatment models in patients with asthma and allergy. This is a first phase of a research project conducted in Denmark to study prerequisites for bridge building between conventional and alternative therapists.

The research questions were: How do the GPs and the CHs describe their treatment models for asthma and allergy? What are the differences and similarities between the treatment models? Is there a logical connection between the components of the GPs and CHs treatment models?

Six GPs and 11 CHs participated in semi-structured interviews. The main difference is in the GPs and CHs descriptions of the purpose of treatment. Similarities are found in the perception of a successful treatment. Both the GPs and the CHs experience treatment effects to be dependent on contextual conditions. Differences and similarities between treatment models are discussed in relation to potential bridge building between conventional and alternative health care.
Patients’ assessments of the effectiveness of homeopathic care in Norway: A prospective observational multicentre outcome study
Authors: Lüdtke R , Steinsbekk A
Published: January 2005

Objective: To evaluate the patient reported effects of homeopathic care 6 months after first consultations.

Methods: Prospective uncontrolled observational multicentre outcome study. All patients visiting 80 homeopaths all over Norway for the first time in eight different time periods from 1996 to 1998 were approached. Patients wrote down their main complaint and scored its impact on daily living on a 100 mm Visual Analogue Scale (VAS) at the first consultation. Six months later they were asked to score again. The homeopaths recorded treatments given for up to two follow-up consultations.

Main outcome measure: Predefined as a reduction of at least 10 mm in the VAS score between the first consultation and follow-up.

Result: Patients 1097 were recruited, 654 completed the follow-up questionnaire. The main complaint improved by at least 10 mm on the VAS for 71% (95% confidence interval 67–74%) of patients. The average reduction was 32 mm (95% CI 30–35 mm). Fifty-one per cent (95% CI 48–55%) of the patients had an improvement in their general well being of more than 10 mm. The mean reduction in the whole group was 14 mm (95% CI 12–16 mm). The proportion of patients using conventional medication reduced from 39% to 16%. Regression analysis showed that lower age and higher baseline score were predictors of better outcome.

Conclusion: In this study, seven out of ten patients visiting a Norwegian homeopath reported a meaningful improvement in their main complaint 6 months after the initial consultation.
The Lichen Flora and Habitats of the Syowa Region, Continental Antarctica
Authors: Inoue M.
Published: January 2005

The lichen flora and habitats in the Syowa region of continental Antarctica were surveyed. The distribution patterns of lichens appear to reflect habitat salinity, derived from wind-blown sea spray. Some halotolerant species are established in saline habitats where snow dunes are well developed. Snow and ice ameliorate the salinity of the habitat and provide a major source of moisture for lichens. Wind-borne drift snow carried by katabatic winds or occasional snow showers also provide the source of moisture to lichens growing on dry rock habitats in the Syowa region.
The Lichen Genus Caloplaca in Polar Regions
Authors: SøChting Ulrik , Olech‡ Maria
Published: January 2005

Extensive material of Caloplacafrom Arctic and Antarctic regions has been critically examined. A list of 49 species is presented for Arctic regions. They are presumed to have a more or less circumpolar distribution. Twenty-two species are listed from the Antarctic region, but about ten more, probably undescribed species, are present there. About one-third of the species in the Antarctic region are bipolar or widespread in cold regions; these include mainly terricolous and muscicolous species and none of them are maritime. It is assumed that migration of the bipolar or cosmopolitan species has taken place along the Andean mountain chain, whereas the maritime polar species have evolved separately in the two hemispheres. The Caloplaca species of the Antarctic region are provisionally assigned to the following distribution types: continental Antarctic, western Antarctic, insul-Antarctic and sub-Antarctic. Caloplaca exsecuta, C. saxicola and C. phaeocarpella are recorded as new to the Antarctic region. Caloplaca johnstonii (Dodge) Søchting & Olech, comb, nov., is established as the correct name of C. tenuis Øvstedal.
Spatial Pattern in Communities of Crustose Saxicolous Lichens
Authors: Dale M. R. T.
Published: January 2005

This paper describes two versions of a new method for detecting and examining spatial pattern in communities of crustose saxicolous lichens. One version is based only on the shapes of the lichen thalli and the second on the identity of their species. These methods are useful for examining the spatial structure of a lichen community for the presence of anisotropy, the phenomenon of having different scales of pattern in different directions. If present, the nature of the anisotropy has implications for our understanding of the processes that give rise to spatial pattern. Preliminary results from communities in the Canadian Rockies suggest that while individual species show some evidence of anisotropy, when all species are considered together, or when only the shapes of the thalli and their boundaries are considered, anisotropy is reduced or absent.
Exposure and Nutrients As Delimiters of Lichen Communities in Continental Antarctica
Authors: Hovenden M.J. , Seppelt R.D.
Published: January 2005

Lichens dominate the terrestrial vegetation of the ice-free regions of continental Antarctica. Vegetation patterns were studied in the Windmill Islands Oasis, Wilkes Land, continental Antarctica, in relation to edaphic features to elucidate the factors that govern lichen distribution and abundance. Vegetation was studied on a low rounded knoll on Clark Peninsula some 3 km North East of the present Casey station. Substratum nutrient levels vary considerably across the knoll due to the presence of an abandoned penguin rookery on the crest and the uneven topography provides both sheltered and exposed sites. Along a 130 m-long transect crossing the knoll from South to North, a total of 25 species of lichen and one moss were identified, the vegetation being dominated by Umbilicaria decussata, Pseudephebe minuscula, Usnea sphacelata and U. antarctica. TWINSPAN analysis of species distributions identified six sociations, the distribution of which were related to substratum structure and chemistry. Several species were restricted to nutrient-rich zones while late-lying snow restricted all species to varying degrees.
Intraspecific Variations of Morphology and Physiology of Temperate to Arctic Populations of Cetraria Nivalis
Authors: Schipperges B. , Kappen L. , Sonesson M.
Published: January 2005

Five populations of the circumpolar Arctic-alpine lichen species Cetraria nivalis were sampled along a latitudinal gradient from the temperate to the Arctic climatic zone. The populations were compared with respect to their CO2 exchange, water relations and morphology/anatomy. Provenances from places along this latitudinal gradient were transplanted in 1983/84 to a site near the Scientific Research Station in Abisko, to see whether they are identical with plastic acclimation ability or whether they represent different ecotypes. The five populations represent two major geographical groups, a ‘southern’ and a ‘northern’ one, with respect to some morphological and anatomical features, chlorophyll content and water relations. The transplanted C. nivalis provenances showed a tendency towards increasing net photosynthetic rates with origin in the higher latitudes. The CO2 exchange response of the native populations was the reverse of this tendency although CO2 exchange was in general flexible. It is concluded that the investigated C. nivalis populations were different ecotypes because of genetic differences and a distinct seasonal plasticity. The ecotypes are interpreted as a result of isolation in different refugia during the Pleistocene.
Computations for nonlinear force driven plasma blocks by picosecond laser pulses for fusion
Authors: CANG Y. , OSMAN F. , HORA H. , ZHANG J. , BADZIAK J. , WOLOWSKI J. , JUNGWIRTH K. , ROHLENA K. , ULLSCHMIED J.
Published: January 2005

The concept of the fast ignitor for laser fusion has led to some modifications in applying petawatt-picosecond (PW-ps) laser-produced high intensity particle beams to ignite deuterium-tritium (DT) fuel. Some very anomalous measurements of ion emission from targets irradiated by picosecond laser pulses led to the development of a skin depth interaction scheme where a defined control of prepulses is necessary. Based on these experimental facts, we have applied a one-dimensional two-fluid hydrodynamic code to understand how the nonlinear ponderomotive force generates two plasma blocks, one moving against the laser light (ablation) and the other moving into the target. This compressed block produces an ion current density of above 10$^{11}$ A cm$^{-2}$ and an ion energy of about 100 keV. This may be a rather promising option to use PW-ps laser pulses for igniting fusion in solid density DT fuel, realizing very high gain controlled fusion reactions.
Surrealism and Quantum Mechanics: Dispersal and Fragmentation in Art, Life, and Physics
Authors: Parkinson Gavin
Published: January 2005

Argument

By the time the members of the Surrealist group had fled Paris and dispersed at the beginning of World War II, they had taken account of quantum mechanics and were seeking various ways of assimilating its findings into Surrealist theory. This can be detected in writings issuing from the Surrealist milieu as early as the late 1920s. However, while writers and thinkers outside the field of physics swiftly expressed their awareness of the epistemological crisis brought about by quantum mechanics, Surrealism's artists began to conscript the concepts and imagery of modern physics into their work only at the end of the 1930s. Focusing on two “second generation” Surrealist painters, the Chilean Roberto Matta and the Viennese Wolfgang Paalen, this article discusses the peculiar difficulties faced by artists in finding a language for the “new reality” revealed by the physicists, and argues that the relocation of Surrealism in a discursive field which includes quantum physics discloses the rationale behind its artists' shift to a semi-abstract language.
Explosive Propositions: Artists React to the Atomic Age
Authors: Petersen Stephen
Published: January 2005

Argument

“How should a modern artist react to the atomic age?” Time magazine posed this question in 1952 to open a review of an exhibition of paintings inspired by the “explosion of the atomic bomb” and by the “discovery of nuclear energy.” The energetic paintings of the Italian Spatial Movement were, according to Time, “almost as explosive as the bomb itself.” “Explosiveness” was a defining feature of much 1950s art, whose main impulse, gestural abstraction, has previously been understood as the urgent expression of the artist's subjectivity. This paper argues that explosiveness in art can also be seen as an “expression” of the realities of the nuclear era. Postwar artists were ambivalent about the explosive forces, both liberating and devastating, that lay within the atom. Toward the end of the 1950s, no longer content merely to represent atomic disintegration, some artists went so far as to propose the outright self-destruction of the work of art as the only fitting means of expression in the atomic age.

One must – and this is not an exaggeration – keep in mind that we are living in the atomic age, where everything material and physical could disappear from one day to another, to be replaced by nothing but the ultimate abstraction imaginable.

– Yves Klein 1958 (Klein 1973, 10)
PULMONARY HYPOPLASIA: WILL ANTENATAL PREDICTION REMAIN AN ELUSIVE GOAL?
Authors: BYRD LOUISE , BULLEN PHILIP
Published: January 2005

Preterm delivery occurs in less than 10% of pregnancies but accounts for more than 70% of all neonatal deaths. Approximately one third of preterm deliveries are associated with preterm prelabour amniorrhexis. In those with infection, labour frequently ensues and survival depends on gestational age at amniorrhexis. In those without infection the pregnancy continues and death is then dependent on the development of pulmonary hypoplasia (PH).
Global inter‐annual gravity changes from GRACE: Early results
Authors: Andersen Ole B. , Hinderer Jacques
Published: January 2005

Fifteen monthly gravity field solutions from the GRACE twin satellites launched more than two years ago have been studied to estimate gravity field changes between 2002 and 2003.The results demonstrate that GRACE is capable of capturing the changes in ground water on inter‐annual scales with an accuracy of 0.4 μGal corresponding to 9 mm water thickness on spatial scales longer than 1300 km. Four of the most widely used global hydrological models have been investigated for their spatial comparison with GRACE observations of inter‐annual gravity field variations due to changes in continental water storage. The Global Land Data Assimilation System model has a spatial correlation coefficient with GRACE observations of 0.65 over the northern hemisphere. This demonstrates that the observed gravity field changes on these scales are largely related to changes in continental water storage.
The effect of rotation on the mesoscale energy cascade in the free atmosphere
Authors: Lindborg Erik
Published: January 2005

A set of numerical simulations of the full Boussinesq equations including system rotation is carried out, in order to fully solve the problem of the origin of the k−5/3 mesoscale wave number energy spectra measured in the free atmosphere. In a companion paper (E. Lindborg, The energy cascade in a strongly stratified fluid, submitted to Journal of Fluid Mechanics, 2005, hereinafter referred to as Lindborg, submitted manuscript, 2005) it is shown that such a spectrum can arise as a result of a special type of forward energy cascade seen in the limit of strong stratification. In this letter we study the effect of rotation on such an energy cascade and show that it can prevail in the presence of system rotation as long as the Rossby number is above a critical value, which is determined to Rocrit ≈ 0.1.
Warm winter spells in the Swiss Alps: Strong heat waves in a cold season? A study focusing on climate observations at the Saentis high mountain site
Authors: Beniston Martin
Published: January 2005

Investigations conducted for several Swiss mountain climatological sites, and in particular the Saentis high mountain site at 2,500 m above sea level, show that positive temperature anomalies during the winter season currently exceed those of all other seasons. These “heat waves” exhibit daily maximum temperature anomalies sometimes in excess of 16°C, and are observed to have increased substantially since the late 1960s. These events are related to the North Atlantic Oscillation (NAO) that exerts significant controls on snow cover and surface‐atmosphere temperature feedbacks in the alpine region. A glimpse to the future is provided for the period 2071–2100, based on regional climate model simulations which suggest that warm winter spells may increase by 30%. The impacts of such events, particularly in terms of snow and water availability and the mountain economies that depend on these resources, need to be incorporated into future strategic resource and economic planning in the Alps.
Multi‐model trends in East African rainfall associated with increased CO2
Authors: McHugh Maurice J.
Published: January 2005

Nineteen coupled ocean‐atmosphere general circulation models participating in the Coupled Model Intercomparison Program (CMIP) were used to analyze future rainfall conditions over East Africa under enhanced CO2 conditions. 80 year control runs of these models indicated that four models produced mean annual rainfall distributions closely resembling climatological means and all four models had normalized root mean square errors well within the bounds of observed variability. East African (10°N–20°S, 25°–50°E) rainfall data from transient 80 year experiments which featured CO2 increases of 1% per year were compared with 80 year control simulations. Results indicate enhanced annual and seasonal rainfall rates, and increased extreme wet period frequency. These results indicate that East Africa may face a future in which mosquito‐borne diseases such as malaria and Rift Valley fever proliferate resulting from increased CO2.
Electron density profiles in the equatorial E region ionosphere derived from a bistatic coherent scatter radar experiment in Perú
Authors: Shume E. B. , Hysell D. L. , Chau J. L.
Published: January 2005

A new bistatic radar system has been developed at the Jicamarca Radio Observatory. The system is a permanent addition to the facility designed to monitor electron density profiles in the equatorial electrojet region using a coherent scatter radar technique that utilizes the Faraday rotation of the scattered signal. A series of radar experiments has been conducted at Jicamarca since March, 2004. In this report, representative E region electron density profiles of the equatorial ionosphere are presented. We compare our electron density estimates with: theoretical electron densities derived from the Chapman production function, electron densities measured by rocket experiments, the International Reference Ionosphere (IRI‐2001) model, and peak electron density estimates from the Jicamarca Digisonde. Overall, the radar measured density profiles have magnitudes and shapes comparable to the electron density estimators mentioned above. However, the measured and IRI‐2001 model density profiles disagree significantly below the E region peak.
Generation mechanism of electrostatic waves in the upstream and shock transition regions of quasi‐parallel shocks
Authors: Matsumoto H. , Iwata M. , Sugiyama T.
Published: January 2005

Primarily, one‐dimensional full‐particle electromagnetic simulations supplemented by a two‐dimensional simulation are performed to investigate the excitation processes of electrostatic waves in quasi‐parallel shocks. The characteristic waves are ion acoustic, ion beam‐mode, and upper‐hybrid waves. In the upstream region, only ion beam‐mode electrostatic waves are excited by the reflected ion beam running almost parallel to the ambient magnetic field. We find that the ion beam‐mode waves evolve into electrostatic solitary waves (ESW) for an appropriate ion beam velocity. The evolution of the ion beam‐mode to ESW is most clearly observed in the simulation when the ambient magnetic field is taken to be parallel to the ion beam direction. We confirm that the ion beam‐mode waves are excited only in the direction parallel to the ambient magnetic field. In the shock transition region (STR) the simulation results show that upper‐hybrid waves are excited on the upstream side of the STR by the reflected ion beam running almost perpendicular to the ambient magnetic field. In the STR region a large‐amplitude and quasi‐monochromatic oblique whistler wave is also excited. On the downstream side of the STR, ion acoustic waves are excited. The mechanism of the excitation of the ion acoustic wave is the current‐driven instability. This instability is generated by the velocity difference between ions and electrons due to electron acceleration in the shock potential. Of these three types of waves, the ion acoustic waves scatter electrons most effectively and contribute to the electron heating processes in the shock region.
Determination of temporal and spatial characteristics of atmospheric gravity waves combining cross‐spectral analysis and wavelet transformation
Authors: Lu Chungu , Koch Steven , Wang Ning
Published: January 2005

In combining cross‐spectral analysis and wavelet transformation we demonstrate how temporal and spatial characteristics of atmospheric gravity waves can be extracted from observed winds and potential temperature. Applying this method to aircraft observational data, we are able to reconstruct a spectrum of high‐frequency monochromatic gravity waves, which demonstrate many localized features such as wave growth, dissipation, and interaction.
Absorbing Aerosol Index: Sensitivity analysis, application to GOME and comparison with TOMS
Authors: de Graaf M. , Stammes P. , Torres O. , Koelemeijer R. B. A.
Published: January 2005

The Absorbing Aerosol Index (AAI) was investigated and used to analyze GOME data and compare it to TOMS data. The physical interpretation of the AAI was studied with an extensive theoretical sensitivity analysis. The dependence of the method on a number of atmospheric, surface, and aerosol properties was studied using a numerical radiative transfer model. It was found to be sensitive to absorbing aerosols with wavelength‐dependent refractive indices and to elevated absorbing aerosols, both with wavelength‐dependent and wavelength‐independent (gray) refractive indices. It was found to be insensitive to clouds, while small size scattering aerosols yield negative values. AAIs were calculated from GOME data for the period July 1995 to December 2000 and compared to TOMS AAI data. In a part of this period, July 1995 to October 1996, no TOMS observations were available, and the GOME data can be used to supplement the TOMS data set. The GOME AAI corresponds very well with known absorbing aerosol events. It suffers from lower spatial resolution and less frequent temporal coverage as compared to TOMS, but is useful as an independent data source of global aerosol measurements.
Comparison of two‐dimensional and three‐dimensional simulations of dense nonaqueous phase liquids (DNAPLs): Migration and entrapment in a nonuniform permeability field
Authors: Christ John A. , Lemke Lawrence D. , Abriola Linda M.
Published: January 2005

The influence of reduced dimensionality (two‐dimensional (2‐D) versus 3‐D) on predictions of dense nonaqueous phase liquid (DNAPL) infiltration and entrapment in statistically homogeneous, nonuniform permeability fields was investigated using the University of Texas Chemical Compositional Simulator (UTCHEM), a 3‐D numerical multiphase simulator. Hysteretic capillary pressure–saturation and relative permeability relationships implemented in UTCHEM were benchmarked against those of another lab‐tested simulator, the Michigan‐Vertical and Lateral Organic Redistribution (M‐VALOR). Simulation of a tetrachloroethene spill in 16 field‐scale aquifer realizations generated DNAPL saturation distributions with approximately equivalent distribution metrics in two and three dimensions, with 2‐D simulations generally resulting in slightly higher maximum saturations and increased vertical spreading. Variability in 2‐D and 3‐D distribution metrics across the set of realizations was shown to be correlated at a significance level of 95–99%. Neither spill volume nor release rate appeared to affect these conclusions. Variability in the permeability field did affect spreading metrics by increasing the horizontal spreading in 3‐D more than in 2‐D in more heterogeneous media simulations. The assumption of isotropic horizontal spatial statistics resulted, on average, in symmetric 3‐D saturation distribution metrics in the horizontal directions. The practical implication of this study is that for statistically homogeneous, nonuniform aquifers, 2‐D simulations of saturation distributions are good approximations to those obtained in 3‐D. However, additional work will be needed to explore the influence of dimensionality on simulated DNAPL dissolution.
Ab initio studies of a water layer at transition metal surfaces
Authors: Vassilev Peter , van Santen Rutger A. , Koper Marc T. M.
Published: January 2005

This paper presents a detailed study of a water adlayer adsorbed on Pt(111) and Rh(111) surfaces using periodic density functional theory methods. The interaction between the metal surface and the water molecules is assessed from molecular dynamics simulation data and single point electronic structure calculations of selected configurations. It is argued that the electron bands around the Fermi level of the metal substrate extend over the water adlayer. As a consequence in the presence of the water layer the surface as a whole still maintains its metallic conductivity—a result of a crucial importance for understanding the process of electron transfer through the water/metal interface and electrochemical reactions in particular. Our results also indicate that there exists a weak bond between the hydrogen of the water and the Rh metal atoms as opposed to the widespread (classical) models based on purely repulsive interaction. This suggests that the commonly used classical interactions potentials adopted for large scale molecular dynamics simulations of water/metal interfaces may need revision. Two adsorption models of water on transition metals with the OH bonds pointing towards or away of the surface are also examined. It is shown that due to the very close values of their adsorption energies one should consider the real structure of water on the surface as a mixture of these simple “up” and “down” models. A model for the structure of the adsorbed water layer on Rh(111) is proposed in terms of statistical averages from molecular dynamics simulations.
Density of localized electronic states in a-Se from electron time-of-flight photocurrent measurements
Authors: Koughia K. , Shakoor Z. , Kasap S. O. , Marshall J. M.
Published: January 2005

Electron time-of-flight transient photocurrents have been investigated in stabilized a-Se as a function of electric field, annealing, aging (relaxation), and alloying with As and doping with Cl.

The distribution of localized states (DOS) in stabilized a-Se has been investigated by comparing the measured and calculated transient photocurrents. The samples were prepared by conventional vacuum deposition techniques. The theoretical analysis of multiple-trapping transport has been done by the discretization of a continuous DOS and the use of Laplace transform formalism. The resulting DOS has distinct features: A first peak at ∼0.30eV below Ec with an amplitude ∼1017eV−1cm−3, a second small peak (or shoulder) at 0.45–0.50 eV below Ec with an amplitude 1014–1015eV−1cm−3, and deep states with an integral concentration 1011–1014cm−3 lying below 0.65 eV, whose exact distribution could not be resolved over the time scale of present experiments. The influence of doping, aging, annealing, and substrate temperature on the DOS distribution has been investigated. The doping with Cl does not affect the amplitudes of the first and second peaks while the concentration of deep states increases dramatically. The alloying with As reduces the density of deep states and seems to increase the amplitude of first and second peaks. The aging substantially reduces the deep states density and the amplitude of the second peak while the amplitude of the first one remains practically unchanged. The results have been interpreted primarily in terms of thermodynamic and intrinsic structural defects in the chalcogenide glass structure.
Calculation of the entropy and free energy by the hypothetical scanning Monte Carlo method: Application to peptides
Authors: Cheluvaraja Srinath , Meirovitch Hagai
Published: January 2005

A new approach, the hypothetical scanning Monte Carlo (HSMC), for calculating the absolute entropy, S, and free energy, F, has been introduced recently and applied first to fluids (argon and water) and later to peptides. In this paper the method is further developed for peptide chains in vacuum. S is calculated from a given MC sample by reconstructing each sample conformation i step-by-step, i.e., calculating transition probabilities (TPs) for the dihedral and bond angles and fixing the related atoms at their positions. At step k of the process the chain’s coordinates that have already been determined are kept fixed (the “frozen past”) and TP(k) is obtained from a MC simulation of the “future” part of the chain whose TPs as yet have not been determined; when the process is completed the contribution of conformation i to the entropy is, Si∼−ln Πk TP(k). In a recent paper we studied polyglycine chains, modeled by the AMBER force field with constant bond lengths and bond angles (the rigid model). Decaglycine [(Gly)10] was studied in the helical, extended, and hairpin microstates, while (Gly)16 was treated only in the first two microstates. In this paper the samples are increased and restudied, (Gly)16 is also investigated in the hairpin microstate, and for (Gly)10 approximations are tested where only part of the future is considered for calculating the TPs. We calculate upper and lower bounds for F and demonstrate that like for fluids, F can be obtained from multiple reconstructions of a single conformation. We also test a more realistic model of (Gly)10 where the bond angles are allowed to move (the flexible model). Very accurate results for S and F are obtained which are compared to results obtained by the quasiharmonic approximation and the local states method. Thus, differences in entropy and free energy between the three microstates are obtained within errors of 0.1–0.3 kcal/mol. The HSMC method can be applied to a macromolecule with any degree of flexibility, ranging from local fluctuations to a random coil. The present results demonstrate that the difference in stability, ΔFmn=Fm−Fn between significantly different microstates m and n, can be obtained from two simulations only without the need to resort to thermodynamic integration. Our long-term goal is to extend this method to any peptide and apply it to a peptide immersed in a box with explicit water.
Time-dependent quantum mechanical wave packet study of the He+H2+(v,j)→HeH++H reaction
Authors: Panda Aditya Narayan , Sathyamurthy N.
Published: January 2005

A detailed three-dimensional time-dependent quantum dynamical study of the He+H2+(v=0–3,j=0)→HeH++H reaction is reported for different vibrational v states of H2+ in its ground rotational (j=0) state over a range of translational Etrans energies on an accurate ab initio potential energy surface published by Palmieri et al. Plots of reaction probability as a function of total energy E reveal a large number of oscillations indicating the presence of a number of reactive scattering resonances. When averaged over total angular momentum J, some of the oscillations survive, indicating that they may be amenable to experimental observation. A comparison of our present results with our earlier results on the McLaughlin–Thompson–Joseph–Sathyamurthy surface and the experimental results from different research groups reveal a good deal of agreement as well as some discrepancies between theory and experiment at the level of state-selected gas phase dynamics.
A study of the phase behavior of a simple model of chiral molecules and enantiomeric mixtures
Authors: Cao M. , Monson P. A.
Published: January 2005

We present a study of the solid-fluid and solid-solid phase equilibrium for molecular models representative of chiral molecules and enantiomeric mixtures. The models consist of four hard sphere interaction sites of different diameters in a tetrahedral arrangement with the fifth hard sphere interaction site at the center of the tetrahedron. The volumetric properties and free energies of the pure enantiomers and binary mixtures were calculated in both fluid and solid phases using isobaric Monte Carlo simulations. The models exhibit essentially ideal solution behavior in the fluid phase with little chiral discrimination. In the solid phase the effects of chirality are much greater. Solid-fluid phase behavior involving the pure enantiomer solids and also racemic compounds was calculated. The calculations indicate that, depending on the relative sizes of the hard sphere interaction sites, packing effects alone can be sufficient to stabilize a racemic compound with respect to the pure enantiomer solids.
Temperature-dependent electroluminescence spectra of poly(phenylene-vinylene) derivatives-based polymer light-emitting diodes
Authors: Wantz G. , Hirsch L. , Huby N. , Vignau L. , Barrière A. S. , Parneix J. P.
Published: January 2005

This study reports on the temperature dependence of electroluminescence spectra of polymer light-emitting diodes based on poly[2,5-bis(3′,7′-dimethyl-octyloxy)1,4-phenylene-vinylene] and poly[2-methoxy-5(2′-ethyl-hexoxy)1,4-phenylene-vinylene]. Temperatures from 80to350K were investigated. A vibronic structure of electroluminescence spectra has been observed. The electroluminescence spectra were then fitted with multiple Gaussian peaks. A blueshift of the zero-phonon line has been reported with increasing temperature, while the full width at half maximum of electroluminescence peaks increased. We propose a model of thermally activated statistic occupation of excited states to fully describe the experimental data. Finally, these electroluminescence changes with temperature only imply a negligible variation of the emitted color.
A highly stabilized hydrogenated amorphous silicon film having very low hydrogen concentration and an improved Si bond network
Authors: Shimizu Satoshi , Kondo Michio , Matsuda Akihisa
Published: January 2005

A highly stabilized hydrogenated amorphous silicon film was developed using a triode deposition system in which a mesh was installed between cathode and substrate in a plasma-enhanced chemical vapor deposition system. The hydrogen concentrations of the resulting films are very low compared with those of conventional films prepared at the same substrate temperature. It was observed that light-soaking stability of the obtained film is promising, which is confirmed by measuring a neutral spin density as well as an I-V characteristic of a Schottky diode. Reduction of densities of higher silane radicals during film growth is an important factor for controlling degradation.