bluuebunny/crossref_metadata_2025 huggingface dataset:
DANGEROUS REPUTATIONS: CHARIOTEERS AND MAGIC IN FOURTH-CENTURY ROME
Authors: LEE-STECUM PARSHIA
Published: September 2006

Roman charioteers had a reputation, and not just for living fast and dying young. Nor was their reputation solely based on the glamour of their occupation, although it is clear that some charioteers could achieve something approaching celebrity status. Roman charioteers (by which I mean charioteers throughout the ancient Roman world) had a reputation of a rather darker stripe. The violence of their occupation, reflected and enhanced by the riotous violence of their supporters, contributed to the perception of charioteers in general as rough, uncouth characters. The gulf between some charioteers' celebrity and their slave status did much to encourage this brutal reputation in the Roman mind.
p53 expression, Ki-67 status, and cell density have no prognostic significance in glioblastomas treated with radio-chemotherapy
Authors: Gross M.W. , Nashwan K. , Mennel H.-D. , Engenhart-Cabillic R.
Published: September 2006

Purpose: To identify subgroups in glioblastoma multiforme (GBM) with different susceptibilities to radio-chemotherapy by p53 protein and Ki-67 expression.

Patients and Methods: Thirty-one patients with primary GBM underwent a combined radio-chemotherapy with topotecan. Percentage of cells expressing p53 protein and Ki-67 antigen was determined immunohistochemically. Additionally, the cell density within the tumour tissue was measured.

Results: Median percentages of p53 and Ki-67 expressing cells were 4.3% (range = 0–28%) and 12.0% (range = 0–28%), respectively. Dividing the cases into two groups by high or low p53 protein 1-year disease-free survival rates were 13.3% and 23.6%. High or low Ki-67 expression showed one-year disease-free survival rates of 18.8% and 17.1%. Neither p53 nor Ki-67 expression showed a significant correlation with disease-free survival or overall survival. Median cell density was 252 cells/field (range = 42–595). 1-year disease-free survival rates were 14.5% and 21.7% in high and low cell density group, respectively. A significant correlation with progression-free survival was observed, whereas the stratification into two groups revealed no significance. Cell density showed a significant inverse correlation with p53 and Ki-67 immunopositivity.

Conclusion:p53 protein and Ki-67 expression seem to be inappropriate for the estimation of prognosis in patients receiving a combined radio-chemotherapy with topotecan.
Attitudes toward euthanasia and physician assisted suicide: A survey among medical students, oncology clinicians, and palliative care specialists
Authors: MARINI M.C. , NEUENSCHWANDER H. , STIEFEL F.
Published: September 2006

Objective: The aim of this study was to compare the results of surveys about attitudes toward euthanasia and related issues that was conducted among palliative care specialists, health care professionals of a cancer center, and first- and second-year medical students.

Methods: By means of an anonymous questionnaire with different hypothetical scenarios concerning physician assisted suicide (PAS) and related issues, 726 members of the Swiss Association for Palliative Care (SAPC), 148 health care professionals of the Institute of Oncology of Italian speaking Switzerland (IOSI), and 140 medical students of the University of Fribourg, Switzerland, were surveyed.

Results: Among palliative care specialists a decreasing number supported PAS, direct active euthanasia (DAE), DAE for psychiatric patients, DAE in incompetent patients, and life terminating acts without explicit request (LAWER). Professionals of the cancer center were more in favor of DAE and PAS than palliative care specialists, but less in favor than medical students.

Significance of results: Significant variations among different professionals exist in attitudes toward euthanasia. The hypothesis that familiarity with the care of severely ill and dying patients is an important underlying factor explaining variance has been confirmed by these surveys.
The impact of a breathlessness intervention service (BIS) on the lives of patients with intractable dyspnea: A qualitative phase 1 study
Authors: BOOTH SARA , FARQUHAR MORAG , GYSELS MARJOLEIN , BAUSEWEIN CLAUDIA , HIGGINSON IRENE J.
Published: September 2006

Objective:Disabling breathlessness is the most common symptom of advanced cardiopulmonary disease. It is usually intractable, even when patients receive maximal medical therapy for their underlying condition. A pilot study was undertaken to evaluate a newly formed palliative Breathlessness Intervention Service (BIS).

Methods:The methodology followed the Medical Research Council's Framework for the Evaluation of Complex Interventions (Phase I). Qualitative interviews were completed with patients and relatives who had used the service and clinicians who had referred to it. The focus of the interviews was the participants' experience of using BIS.

Results:Patients valued the positive educational approach taken to breathlessness, emphasizing what was possible rather than what had been lost. Non-pharmacological strategies, especially the hand-held fan and exercises, were rated very helpful and new to patients. Participants reiterated that breathlessness was frightening and isolating, exacerbating the disability it caused: the easy access to advice and flexibility of BIS helped to alleviate this. Participants wanted a written record of the advice given. Carers welcomed the focus on their needs. Clinicians valued sharing the management of patients with an intractable problem.

Significance of results:This Phase I study has helped to remodel the service rapidly by uncovering the aspects of BIS that users find most valuable and areas that need change or improvement. The BIS needs to provide written information, to reinforce and extend contacts with other agencies to build on support it already provides for patients and carers, and extend its flexibility and accessibility. Providing a “drop-in” service and continuing education after the initial program of contacts is completed could be a useful service development, warranting further evaluation. A qualitative methodology involving service users and referrers can help to shape service development rapidly.
Delirium: The clinical concept
Authors: MACLEOD A.D. (SANDY)
Published: September 2006

Delirium is a common syndrome complicating terminal illness. It is underrecognized partly because it is a difficult clinical concept. Consciousness, awareness, alertness, arousal, awakeness, vigilance, and attention are some of the terms used to describe the deficits occurring in delirium. Though interconnected, they are often loosely defined. Alertness is the primary impairment, and attentional deficits are objective clinical indices of the cognitive impairments of delirium. Simple bedside assessments of delirium are considered. The “deliriant” threshold and the symptomatic fluctuations of delirium are important concepts in the understanding of delirium. Jackson's conceptualization of the nervous system is relevant to delirium. Raising the deliriant threshold by multicomponent interventions is the intent of the palliative management of terminal delirium.
Identity Exploration and Commitment of Albanian Youth as a Function of Social Opportunity Structure
Authors: Orgocka Aida , Jovanovic Jasna
Published: September 2006

This study examined how social opportunity structure influences identity exploration and commitment of Albanian high school students. A total of 258 students completed a questionnaire that gauged their identity exploration and commitment in three domains: education, occupation, and family. ANOVA results indicated that, overall, students scored highest in exploration in the domain of education and in commitment in the domain of family. Students' exploration and commitment were linked to gender. Albanian female students scored higher than male students in exploration and commitment regarding education and family. Perceived work opportunities in Albania or abroad also significantly moderated participants' exploration in the domain of education and were associated with commitment in education and occupation. As one of the first studies to explore Albanian youth's identity development in relation to social opportunity structure, findings are discussed in light of furthering the field of Albanian adolescent and youth development.
Foreign Language Proficiency and Working Memory Capacity
Authors: van den Noort Maurits W.M.L. , Bosch Peggy , Hugdahl Kenneth
Published: September 2006

In this study, the hypothesis that working memory capacity interacts with (foreign) language proficiency was tested on multilinguals, who were native (L1) Dutch speakers, were fluent in their second (L2) language, German, and had recently started the acquisition of their third (L3) language, Norwegian. So far, the results of second-language studies on simple and complex working-memory tasks are mixed. In previous second-language studies, however, languages that belong to different linguistic groups were used. The question arises whether the interaction between working memory capacity and language proficiency is language-specific. In our multilingualism study we, therefore, controlled for this. Both simple (digit-span) and complex working-memory tasks (reading-span task and letter-number ordering) were used. The general results show that differences in performance between L1, L2, and L3 can be found on both simple and complex working-memory tasks, supporting the working memory capacity interaction hypothesis.
GeroPsychology
Authors: Fernández-Ballesteros Rocío
Published: September 2006

Europe is the oldest continent in the world; in the year 2000, about 17% of Europeans (EU-15) were older than 65, and projections say that in the year 2025 one-fourth of the European population will have reached this age. Nevertheless, the threat to the population is not aging but disability; although life expectancy at birth is about 80, the expected number of years with disability runs from 5.7 to 7.2 years ( WHO, 2002 ). The United Nations recently approved the II International Plan of Action on Aging (MIPAA, UN, 2002) with special recommendation for the European region. This situation is highly demanding both for the science of psychology and for European psychologists. This article introduces a set of research programs - linked with the three priority directions of the MIPAA - as examples of how psychology is one of the disciplines calling for improved quality of life and well-being in old age and, therefore, GeroPsychology as an applied field should be consolidated in the next decades.
Personality and Intelligence
Authors: Chamorro-Premuzic Tomas , Furnham Adrian , Petrides Konstantinos
Published: September 2006

This paper explores the relationship between Eysenckian personality, as operationalized by the Eysenck Personality Profiler (EPP), and verbal and numerical ability. A total of 118 (87 female) working adults participated in the study. Bivariate correlations showed that numerical ability was negatively associated with Caution, whereas verbal ability was negatively associated with Neuroticism, Introversion, and Dissimulation. Two hierarchical regressions showed that the EPP variables (primarily Dissimulation) were significant predictors of verbal, but not Numerical ability, accounting for 30% of the total variance. Theoretical and applied implications for the personality-intelligence interface are discussed, particularly in regards to Chamorro-Premuzic and Furnham's (2004) intellectual competence model.
Psychological Adjustment of Melanoma Survivors
Authors: Hamama-Raz Y. , Solomon Z.
Published: September 2006

The study examines the contributions of hardiness, attachment style, and cognitive appraisal to the psychological adjustment of 300 survivors of malignant melanoma: The findings show that the survivors' adjustment is by far better predicted by their personal resources and cognitive appraisal than by their sociodemographic features (with the exception of marital status) and features of their illness. Of all the variables, their adjustment was best predicted by their attachment style, with secure attachment making for greater well-being and less distress. These findings add to the ample evidence that personal resources help persons to cope with stressful or traumatic events.
Predicting the temperature dependence of microbial respiration in soil: A continental‐scale analysis
Authors: Fierer Noah , Colman Benjamin P. , Schimel Joshua P. , Jackson Robert B.
Published: September 2006

The production of CO2 by soil microorganisms is an important component of the global carbon cycle, and its temperature sensitivity is poorly constrained in global models. To improve our understanding of the factors controlling the temperature dependence of soil microbial respiration, we analyzed the temperature sensitivity of labile soil organic carbon decomposition for 77 soils collected from a wide array of ecosystem types. Across all of the soils, the average Q10 value (the factor by which decomposition rates increase for a 10°C increase in temperature) was 3.0, but the range in Q10 values was substantial (2.2 to 4.6). A large percentage (45%) of the variation in Q10 values could be explained by the relative rate of microbial respiration per unit organic C, an analog for C quality. This result provides support for the “carbon quality‐temperature” hypothesis that directly links the temperature dependence of microbial decomposition and the biochemical recalcitrance of soil organic carbon. A smaller percentage (17%) of the variability in Q10 values could be explained by the mean monthly temperature at the time of sampling, suggesting that microbial communities may adapt to the antecedent temperature regime. By showing that the Q10 of microbial respiration in soil is largely predictable under standardized incubation conditions, this work increases our understanding of the temperature sensitivity of labile soil organic carbon stores.
Simultaneous mesosphere‐lower thermosphere and thermospheric F region observations using middle and upper atmosphere radar
Authors: Balan N. , Kawamura S. , Nakamura T. , Yamamoto M. , Fukao S. , Oliver W. L. , Hagan M. E. , Aylward A. D. , Alleyne H.
Published: September 2006

Simultaneous MLT (mesosphere‐lower thermosphere) and thermospheric F region (upper thermosphere and ionosphere together) observations conducted using the middle and upper atmosphere (MU) radar (35°N, 136°E) in alternate meteor and incoherent scatter modes in October 2000 and March 2001 are presented. The continuous observations, each lasting more than a week, provide simultaneous zonal and meridional wind velocities at MLT altitudes (80–95 km), meridional wind velocity in the upper thermosphere (220–450 km), and electron density and peak height in the ionosphere with a time resolution of 1.5 hours. The data seem to suggest that the upper atmospheric regions could be dynamically coupled through mean winds, tides, and waves. Diurnal (24‐hour) and semidiurnal (12‐hour) tides and waves of periods 16–20 hours and 35–55 hours coexist at MLT and upper thermosphere altitudes, and the waves become stronger than tides at mesopause (≈88 km) in both October and March. The data in these equinoctial months also show large differences in mean winds, tides, and waves in the MLT region. The amplitudes and phases of the 24‐hour and 12‐hour tides at MLT altitudes are compared with those predicted by the global scale wave model (GSWM). The model qualitatively predicts the observed growth of the tides with altitude but does not predict the 12‐hour tide becoming stronger than the 24‐hour tide at altitudes above mesopause in October.
Plasma wave source location using CLUSTER as a spherical wave telescope
Authors: Constantinescu O. D. , Glassmeier K.‐H. , Motschmann U. , Treumann R. A. , Fornaçon K.‐H. , Fränz M.
Published: September 2006

The use of sensor arrays in space opens up the possibility to investigate the source location of plasma waves. In order to do so, we generalize the wave telescope technique to use spherical waves instead of plane waves. The new tool determines the center of the wavefronts locally measured by the sensor array. This virtual source can be related with the position of the source generating the detected waves provided the wave propagation mode and medium properties are known. Moreover, the motion of the source region can be derived, as well as its basic geometrical characteristics. In this work we give the theoretical background for the new tool and examples of location analysis based on synthetic data. An example based on CLUSTER magnetic field data in the dayside magnetosheath reveals a virtual source region elongated in the magnetic field direction, moving with the plasma flow in the vicinity of the spacecraft configuration.
Two‐dimensional ageostrophic secondary circulation at ocean fronts due to vertical mixing and large‐scale deformation
Authors: Nagai T. , Tandon A. , Rudnick D. L.
Published: September 2006

Ageostrophic secondary circulation (ASC) in frontal data sets have been previously diagnosed using only adiabatic versions of Omega equations. This study includes the effect of vertical mixing on such diagnostics. Modified quasi‐geostrophic and semigeostrophic balance equations are examined for the existing Azores front data sets and idealized fronts in the presence of diabatic vertical mixing as well as a large‐scale deformation field. The relevant dimensionless parameter representing the relative importance of large‐scale deformation and vertical mixing is the inverse of the Ekman number based on the deformation rate (αH2/Ao), where α is large‐scale deformation rate, H is vertical scale of the front, and Ao is the maximum vertical eddy viscosity; when this parameter is smaller than O(102), the influence of vertical mixing may be important. Other relevant parameters include Burger number, Bu, and Prandtl number, Pr. The vertical velocity in ASCs caused by diabatic mixing in all diagnostics solutions except for large Bu cases shows good agreement with the Garrett‐Loder scaling. The structure of ASCs is found to be sensitive to Pr. The diagnostics of ASCs for the Azores front data set indicates that the vertical mixing intensifies the ASC in the upper ocean (∼100 m) and should not be neglected, when the large‐scale deformation rate, α, is O(10−6 s−1) or smaller. The magnitude of vertical velocity in ASCs due to mixing contributions reaches ∼O(10 m d−1) with downwelling on the dense side and upwelling on the less dense side of Azores front.
Gravity waves and momentum fluxes in the mesosphere and lower thermosphere using 430 MHz dual‐beam measurements at Arecibo: 1. Measurements, methods, and gravity waves
Authors: Janches Diego , Fritts David C. , Riggin Dennis M. , Sulzer Michael P. , Gonzalez Sixto
Published: September 2006

We report here and in a companion paper by Fritts et al. (2006a) on a new use of the UHF radar at the Arecibo Observatory in Puerto Rico. We have employed the 430 MHz radar for incoherent scatter measurements of radial wind spectra at altitudes from ∼71 to 95 km using the Gregorian and line‐feed antennas to define beam angles inclined 15° to the east and west of zenith. We find that the two beams define radial velocities with sufficient accuracy to characterize both the gravity waves and the momentum fluxes due to these waves over the majority of the observed altitude range during daylight hours. The characteristics of the gravity waves inferred from these measurements include (1) vertical scales ranging from ∼2 to 20 km, (2) downward phase progression of the dominant gravity waves up to ∼5 ms−1, and (3) vertical wave number spectra having slopes near a value (−3) expected for saturated gravity waves. Gravity wave frequency spectra and momentum fluxes are addressed in the companion paper.
Gravity waves and momentum fluxes in the mesosphere and lower thermosphere using 430 MHz dual‐beam measurements at Arecibo: 2. Frequency spectra, momentum fluxes, and variability
Authors: Fritts David C. , Janches Diego , Riggin Dennis M. , Stockwell Robert G. , Sulzer Michael P. , Gonzalez Sixto
Published: September 2006

Janches et al. (2006) described a new dual‐beam use of the 430 MHz incoherent scatter radar at the Arecibo Observatory in Puerto Rico. We found the technique to define the radial wind field in the mesosphere and lower thermosphere with sufficient accuracy to characterize gravity waves occurring at high frequencies and small spatial scales over an extended altitude range. The coplanar, dual‐beam experiment was also designed to test the ability of the system to measure gravity wave momentum fluxes and their frequency distributions, and we report here on those results. Initial measurements were of limited duration and necessarily represent a case study, but they demonstrate the value of such measurements for studies of GW variability and large‐scale interactions. Radial velocity variances reveal preferential eastward propagation for most intervals and altitudes, with the greatest propagation bias at lower altitudes and later times on 11 September when strong westward mean winds favor strong gravity filtering. The momentum fluxes observed during this experiment had ∼50‐min averages that were often near zero, occasionally achieved amplitudes of ∼20 to 50 m2s−2, displayed significant consistency in altitude, and exhibited an approximate anticorrelation with the zonal wind field in cases with significant momentum fluxes. Frequency spectra defined the major contributions to the momentum fluxes, while S transforms were employed to examine the temporal variability of the GWs and momentum fluxes in greater detail.
Polar stratospheric ice cloud above Spitsbergen
Authors: Maturilli Marion , Dörnbrack Andreas
Published: September 2006

Within the extremely cold and stable polar vortex of winter 2004–2005 a polar stratospheric ice cloud was observed from Ny‐Ålesund (Spitsbergen) on 26 January 2005. The observation of a cloud with backscatter ratios up to 23 and volume depolarization larger than 50% is unique in our 15 year ground‐based lidar data record. Simultaneous balloon‐borne water vapor measurements indicate the presence of mesoscale ice clouds nearby. Normally, low horizontal wind speeds inside the inner vortex prevent vertical wave propagation. However, the rare coincidence of different meteorological processes occurring during a poleward‐breaking Rossby wave event caused favorable conditions for the vertical propagation of mountain waves excited by the flow past Spitsbergen. Detailed meteorological analysis shows that the ice particle formation processes on 26 January 2005 were most likely provoked by mesoscale stratospheric temperature anomalies, leading to a local reduction in water vapor.
NeXtYZ: Three‐dimensional electron density inversion for dynasonde ionograms
Authors: Zabotin N. A. , Wright J. W. , Zhbankov G. A.
Published: September 2006

The problem of electron density inversion of digital ionograms is reconsidered from the viewpoints of new possibilities and of modern requirements. The data processing system of an advanced ionosonde (the dynasonde) provides accurate measurements not only of echo group range but also of direction of arrival, among other physical parameters, thus yielding the three‐dimensional distribution of apparent echolocations in each ionogram recording. An iterative ray‐tracing approach is described here to recover the parameters of a quite sophisticated three‐dimensional (so‐called wedge‐stratified ionosphere) model of the local electron density distribution, characterizing its actual vertical Ne(h) profile together with horizontal gradients and general tilts. The power of a contemporary PC is sufficient to accomplish this analysis quickly. This approach is implemented in the algorithm introduced here, is named “NeXtYZ,” and is pronounced “next wise.”
Predicting Solar Cycle 24 and beyond
Authors: Clilverd Mark A. , Clarke Ellen , Ulich Thomas , Rishbeth Henry , Jarvis Martin J.
Published: September 2006

We use a model for sunspot number using low‐frequency solar oscillations, with periods 22, 53, 88, 106, 213, and 420 years modulating the 11‐year Schwabe cycle, to predict the peak sunspot number of cycle 24 and for future cycles, including the period around 2100 A.D. We extend the earlier work of Damon and Jirikowic (1992) by adding a further long‐period component of 420 years. Typically, the standard deviation between the model and the peak sunspot number in each solar cycle from 1750 to 1970 is ±34. The peak sunspot prediction for cycles 21, 22, and 23 agree with the observed sunspot activity levels within the error estimate. Our peak sunspot prediction for cycle 24 is significantly smaller than cycle 23, with peak sunspot numbers predicted to be 42 ± 34. These predictions suggest that a period of quiet solar activity is expected, lasting until ∼2030, with less disruption to satellite orbits, satellite lifetimes, and power distribution grids and lower risk of spacecraft failures and radiation dose to astronauts. Our model also predicts a recovery during the middle of the century to more typical solar activity cycles with peak sunspot numbers around 120. Eventually, the superposition of the minimum phase of the 105‐ and 420‐year cycles just after 2100 leads to another period of significantly quieter solar conditions. This lends some support to the prediction of low solar activity in 2100 made by Clilverd et al. (2003).
Probabilistic modeling of eruptive activity at Etna volcano using InSAR surface displacements and ATSR thermal radiance
Authors: Patrick M. R. , Frazer L. N. , Brooks B. A.
Published: September 2006

Satellite monitoring offers a powerful means to regularly characterize the mechanical and thermal states of active volcanoes. Satellite‐measured surface inflation and radiant heat flux reflect the pressurization and discharge, respectively, of a magmatic system, suggesting that studying these parameters together may help in better understanding future eruptive activity. We incorporate InSAR surface displacement data and ATSR thermal radiance data into a probabilistic model for activity at Etna volcano in 1996–2000, when surface deformation and thermal radiance appeared to be related in a periodic fashion. The probabilistic approach addresses both the magnitude and timing of eruptive events, based upon a simple physical model of eruptions as renewal processes. We anticipate that this approach could serve as a framework for probabilistic assessment in eruption scenarios with persistent activity and multiple monitoring datastreams.
Self‐formed bedrock channels
Authors: Wobus Cameron W. , Tucker Gregory E. , Anderson Robert S.
Published: September 2006

An effective physics‐based rule for the evolution of bedrock channel cross sections is required for quantitative modeling of the roles of climate, tectonics, and sediment supply in setting bedrock longitudinal profiles and landscape form. Here we propose a modeling strategy in which the spatial pattern of erosion rates in a channel cross section is calculated, allowing exploration of the origin of the channel cross‐sectional profile, and of the dependence of channel width on flow discharge and channel slope. Our approach reproduces many of the scaling relationships observed in natural systems, including power‐law width‐discharge (W∼Q0.4) and width‐slope (W∼S−0.2) relationships. Models of channel cross‐sections linked in series and subject to varying rock uplift (baselevel lowering) rates produce concave‐up longitudinal profiles with power‐law slope‐uplift (S∼B1.31) and width‐uplift (W∼B−0.24) relationships. Our modeling strategy can easily be adapted to handle i) better representations of erosional processes, ii) better approximations of the flow structure, and iii) the role of non‐uniform sediment mantling of the bed.
Abrupt climatic events during the last glacial‐interglacial transition in Alaska
Authors: Hu Feng Sheng , Nelson David M. , Clarke Gina H. , Rühland Kathleen M. , Huang Yongsong , Kaufman Darrell S. , Smol John P.
Published: September 2006

Evidence is mounting that abrupt climatic shifts occurred during the last glacial‐interglacial transition (LGIT) in the North Atlantic and other regions. However, few high‐resolution climatic records of the LGIT exist from the high latitudes of the North Pacific rim. We analyzed lake sediments from southwestern Alaska for biogenic silica, organic carbon, organic nitrogen, diatom assemblages, and compound‐specific hydrogen isotopes. Results reveal climatic changes coincident with the Younger Dryas, Intra‐Allerød Cold Period, and Pre‐Boreal Oscillation. However, major discrepancies exist in the paleoclimate patterns of the Bølling‐Allerød interstadial between our data and the GISP2 δ18O record from Greenland, and causes are uncertain. These data suggest that the North Pacific and North Atlantic experienced similar reversals during climatic warming of the LGIT but that the Bølling‐Allerød cooling trend in the GISP2 δ18O record is probably not a hemispheric or global pattern.
Quantification and hemispheric asymmetry of low‐latitude geomagnetic disturbances caused by solar wind pressure enhancements
Authors: Huang Chao‐Song , Yumoto Kiyohumi
Published: September 2006

The solar wind dynamic pressure has significant influence on the magnetic field of the Earth. When the magnetosphere is compressed by a solar wind pressure enhancement, the dayside magnetopause current is enhanced, resulting in an increase in the magnetic field inside the magnetosphere and on the ground. In this paper we present the statistical results of low‐latitude geomagnetic disturbances caused by solar wind pressure enhancements under different interplanetary magnetic field (IMF) orientations, including northward, southward, and fluctuating IMF. One of the prominent features of the geomagnetic disturbances revealed in this study is the hemispheric asymmetry and its seasonal dependence. Geomagnetic disturbances in the Northern Hemisphere summer are in general larger than those found simultaneously in the Southern Hemisphere and are smaller in the Northern Hemisphere winter than in the corresponding southern stations. The ratio of the average geomagnetic disturbance at magnetic latitude 36°S to that at magnetic latitude 36°N in winter is 1.36 for northward IMF, 1.64 for fluctuating IMF, and 1.79 for southward IMF. The corresponding ratio at 24° magnetic latitude is 1.49, 1.64, and 2.0, respectively. We suggest that the hemispheric asymmetry is caused by the tilt of the Earth's magnetic axis. Our statistics includes a large data set (160 cases in total), and we derive an empirical formula between the solar wind pressure enhancement and geomagnetic disturbances: ΔH = k( − ), where ΔH is the change of the low‐latitude geomagnetic field and measured with nT, Psw is the solar wind pressure and measured with nPa, and k is a constant. The value of k depends on seasons and is 18.4 if all data are included.
Tidal dynamics in channels: Single channels
Authors: Souza A. J. , Hill A. E.
Published: September 2006

Intricate networks of tidal channels such as are found in fjordic, barrier island and branching estuarine systems are often at risk from contaminant inputs and can be important as spawning grounds or migration pathways for marine organisms. These intricate systems are rarely spatially resolved in regional‐scale numerical tidal models, and the setting up of a specific detailed numerical model for the purpose of rapidly assessing the likely tidal behavior of such geometrically complex systems carries a high overhead. As a first step we describe a simple, not published before, algorithm, which permits rapid assessment of the linear tidal dynamics in a single tidal channel. The method will be extended to channel networks in a companion article. The method needs only a minimum of input data, namely, (1) the forcing tidal elevation amplitude and phase at the entrances of the channel directly exposed to the open sea and (2) the length and depth of the channel. The performance of the method is tested against observations in the Menai Straits, UK, by applying the case of a single channel forced at either end with friction.
Nonequilibrium self-organization phenomena in active Langmuir monolayers
Authors: Shibata Tatsuo , Mikhailov Alexander S.
Published: September 2006

Langmuir monomolecular layers, formed by amphiphilic molecules at liquid-air interfaces and containing a fraction of chiral molecules, are theoretically investigated. These monolayers can be brought out of thermal equilibrium by applying a gradient of small molecules across the interface, resulting in the leakage flow. We show that, when splay coupling between the orientation field and the local concentration of chiral molecules in the monolayer is taken into account, this nonequilibrium soft matter system can show complex wave behavior, including the development of target wave patterns, spiral waves, and dense regions filled with inwardly propagating waves.
A multichord soft x-ray diagnostic for electron temperature profile measurements in RFX-mod
Authors: Bonomo F. , Franz P. , Murari A. , Gadani G. , Alfier A. , Pasqualotto R.
Published: September 2006

We report on the design and first results obtained with a multichord diagnostic for the measurement of the electron temperature profiles in RFX-mod. The diagnostic consists of four groups of five photodiodes each, measuring the soft x-ray plasma emissivity through four pinholes. Each pinhole houses a beryllium filter with different thickness. The 20 lines of sight defined by the diodes and the pinholes, emanating from the same porthole and looking at the same poloidal section, are coupled two by two. This results in a fan of ten pairs of chords covering the outboard section of the RFX-mod plasma. The double-foil technique applied to each pair of chords allows for the estimation of the electron temperature. The spatial resolution of the diagnostic permits to detect detailed features of the electron temperature profiles with a high time accuracy: the several kilohertz bandwidth electronic system allows for following in time the plasma dynamic evolution. Comparisons of the estimated Te with the Thomson scattering diagnostic and with the on-axis multifoil spectrometer are also reported.
Determination of the high pressure elasticity of cobalt from measured interfacial acoustic wave velocities
Authors: Crowhurst J. C. , Antonangeli D. , Brown J. M. , Goncharov A. F. , Farber D. L. , Aracne C. M.
Published: September 2006

We have used impulsive stimulated light scattering to measure the velocity of an acoustic wave propagating along the interface formed by a cobalt single crystal in contact with liquid helium to a pressure of 10GPa. We have combined the measured velocities with x-ray diffraction data of cobalt under compression to obtain the elastic tensor elements c44 and c66, and with lower precision c11, c12, and c13. We further show that using published inelastic x-ray scattering results for c33 the associated uncertainties of c11, c12, and c13 are substantially reduced.
Spatial transfer function for the beam emission spectroscopy diagnostic on DIII-D
Authors: Shafer M. W. , Fonck R. J. , McKee G. R. , Schlossberg D. J.
Published: September 2006

The spatial transfer function for the beam emission spectroscopy (BES) diagnostic is critical to quantitatively interpret local density fluctuation measurements. A three-dimensional geometrical calculation of the spatial transfer function is presented for the upgraded BES diagnostic on DIII-D to determine its spatial resolution and wave-number sensitivity. The spatial transfer function calculation for the BES system on DIII-D incorporates the high speed (f∕2) collection optics, an optical fiber bundle, neutral beam-sight line geometry, the neutral beam cross-section intensity profile, magnetic field pitch angle, as well as atomic physics of the finite atomic transition time of the collisionally excited beam atoms. The resulting imaged volumes for each BES channel typically have ∼1–2cm radial and poloidal resolutions. In addition, the viewing volume is nominally aligned along a magnetic field line to minimize spatial smearing of the field-aligned turbulent eddies. This calculation is crucial for performing the proper deconvolution of measured signals to determine correlation lengths and wave-number spectra of the measured density fluctuations, and is also required for applying synthetic diagnostics to nonlinear turbulence simulation codes (e.g., GYRO) to relate code output to measured signals.
Focusing, in-chamber spectrometer triplet for high resolution measurements on the Sandia Z facility
Authors: Wenger D. F. , Sinars D. B. , Rochau G. A. , Bailey J. E. , Porter J. L. , Faenov A. Ya. , Pikuz T. A. , Pikuz S. A.
Published: September 2006

An early prototype of a focusing spectrometer with one-dimensional (1D) spatial resolution (FSSR) instrument was previously developed for use in the vacuum chamber of the Sandia Z facility [Sinars et al., J. Quant. Spectrosc. Radiat. Transf. 99, 595 (2006)]. This instrument used a single, spherically bent crystal to measure time-integrated Ar spectra from 0.295–0.378nm with λ∕Δλ>2000 and a 1D axial spatial resolution of ∼50μm. We present the design of a final version of this instrument that improves the shielding, can be aligned more accurately, and uses three crystals instead of one. The last change enables coverage of multiple spectral ranges if different crystals are used, or multiple times if identical crystals and time-gated detectors are used. We also present results from initial prototyping tests on the Z facility using two crystals in a time-integrated mode.
Analysis of multifrequency interferometry in a cylindrical plasma
Authors: Kraft D. J. , Bengtson Roger D. , Breizman B. N. , Chavers D. G. , Dobson C. C. , Jones J. E. , Jacobson V. T.
Published: September 2006

A microwave interferometer operating simultaneously at 70, 90, and 110GHz is used to measure line integrated electron density in a plasma column in the VX-20 experiment. Interferometer beam sizes are a significant part of the plasma radius at some locations. We model the wave propagation through the plasma using a scalar wave approximation with assumptions of a Gaussian beam profile and plasma spatial profile. The phase shifts obtained from this model are compared with standard thin beam calculations and experimental data.
Magnetic resonance imaging of chemical waves in porous media
Authors: Taylor Annette F. , Britton Melanie M.
Published: September 2006

Magnetic resonance imaging (MRI) provides a powerful tool for the investigation of chemical structures in optically opaque porous media, in which chemical concentration gradients can be visualized, and diffusion and flow properties are simultaneously determined. In this paper we give an overview of the MRI technique and review theory and experiments on the formation of chemical waves in a tubular packed bed reactor upon the addition of a nonlinear chemical reaction. MR images are presented of reaction-diffusion waves propagating in the three-dimensional (3D) network of channels in the reactor, and the 3D structure of stationary concentration patterns formed via the flow-distributed oscillation mechanism is demonstrated to reflect the local hydrodynamics in the packed bed. Possible future directions regarding the influence of heterogeneities on transport and reaction are discussed.
Comparison of the three tokamak plasma tomography methods for high spatial resolution and fast calculation
Authors: Kim Junghee , Lee Seung Hun , Choe W.
Published: September 2006

High spatial resolution tomographic reconstructions with several thousand pixels were performed by three different reconstruction algorithms. To overcome the increased ill posedness due to the use of a large number of pixels, the fast maximum entropy method (MEM) and the Phillips-Tikhonov method were used without any biasing information. The developed spatially resolved fast tomography codes were tested with the KSTAR plasma-like emissivity phantom and the TCV soft x-ray data. The reconstruction results were compared with those by the minimum Fisher information method, and these three methods shows the reliable reconstruction results. Speedup of the calculation was attempted by implementing the parallel computing technique via MATHLINK in the fast MEM code written in the MATHEMATICA language. The calculation speed of the fast MEM code was improved by about ten times without loss of accuracy despite the large number of pixels (2700 and 3500pixels).
Microchameleons: Nonlinear chemical microsystems for amplification and sensing
Authors: Bishop K. J. M. , Gray T. P. , Fialkowski M. , Grzybowski B. A.
Published: September 2006

In biological systems, the coupling of nonlinear biochemical kinetics and molecular transport enables functional sensing and “signal” amplification across many length scales. Drawing on biological inspiration, we describe how artificial reaction-diffusion (RD) microsystems can provide a basis for sensing applications, capable of amplifying micro- and nanoscopic events into macroscopic visual readouts. The RD applications reviewed here are based on a novel experimental technique, WETS for Wet Stamping, which offers unprecedented control over RD processes in microscopic and complex geometries. It is discussed how RD can be used to sense subtle differences in the thickness and/or absorptivity of thin absorptive films, amplify macromolecular phase transitions, detect the presence and quality of self-assembled monolayers, and provide dynamic spatiotemporal readouts of chemical “metabolites.”
Strange nonchaotic attractors in Harper maps
Authors: Haro Àlex , Puig Joaquim
Published: September 2006

We study the existence of strange nonchaotic attractors (SNA) in the family of Harper maps. We prove that for a set of parameters of positive measure, the map possesses a SNA. However, the set is nowhere dense. By changing the parameter arbitrarily small amounts, the attractor is a smooth curve and not a SNA.
Rupture force changes between the third strand and the double strand within an oligonucleotide-directed triplex in the presence of intercalative molecules
Authors: Ling Liansheng , Butt Hans-Jürgen , Berger Rüdiger
Published: September 2006

The rupture force changes to separate the third strand from the duplex within an oligonucleotide-directed triplex (triplex DNA) were measured in the presence of small DNA binding molecules by means of atomic force spectroscopy. Rupture force histograms revealed a rupture force of 44.3±0.4pN to separate the third strand from duplex DNA in pure buffer solution at a rupture velocity of 400nm∕s. In 30μM of Ru(bipy)2(dppz)2+ buffer solution an increase of rupture force to 57±2.2pN was observed. For 30μM Ru(phen)2(dppz)2+ a rupture force of 65.1±3.9pN was determined. These results show that both intercalative molecules increase the stability of triplex DNA significantly.
Menger sponge-like fractal body created by a novel template method
Authors: Mayama H. , Tsujii K.
Published: September 2006

We have established experimental strategies on how to create a Menger sponge-like fractal body and how to control its fractal dimension. The essence was to utilize alkylketene dimer (AKD), which spontaneously forms super-water-repellent fractal surface. We prepared “fractal AKD particles” with fractal surface structure as templates of pores in fractal body. The fractal body was synthesized by filling the remained space between the packed template particles with a tetramethyl orthosilicate solution, solidifying it by the sol-gel process, and removing the template by calcinations. We have succeeded in systematically creating fractal bodies of silica with different cross-sectional fractal dimensions Dcs=1.87, 1.84, and 1.80 using “fractal template particles” compressed under the ratio=1.0, 2.0, and 3.0, respectively. We also discussed the possibilities of their fractal geometries in comparison with mathematical models. We concluded that the created fractal bodies were close to a Menger sponge and its modified one. Our experimental strategy allows us to design fractality of porous materials.
Phase space quantum mechanics - Direct
Authors: Nasiri S. , Sobouti Y. , Taati F.
Published: September 2006

Conventional approach to quantum mechanics in phase space, (q,p), is to take the operator based quantum mechanics of Schrödinger, or an equivalent, and assign a c-number function in phase space to it. We propose to begin with a higher level of abstraction, in which the independence and the symmetric role of q and p is maintained throughout, and at once arrive at phase space state functions. Upon reduction to the q- or p-space the proposed formalism gives the conventional quantum mechanics, however, with a definite rule for ordering of factors of noncommuting observables. Further conceptual and practical merits of the formalism are demonstrated throughout the text.
Charge injection and tunneling mechanism of solid state reaction silicon nanocrystal film
Authors: Lau H. W. , Tan O. K. , Trigg D. A.
Published: September 2006

Solid state reaction silicon nanocrystals (Si nc’s) of an average size of 10nm have been synthesized. Charge transport characteristics have been investigated as a function of temperature and voltage. From 305to400K, it is found that space-charge-limited current (SCLC), with an exponential distribution of trapping states, dominates the conduction mechanism. High resolution transmission electron microscope images indicate that microscopic structural defects, such as dislocations, are present in this solid state reaction Si nc. These defects are a possible source of trapping states as described in the SCLC model. Using this model, a trap density of Nt=1.46×1018cm−3 and a characteristic trap temperature Tt=2057K can be extracted. The trap density is two orders of magnitude greater than the Si nc density, showing that the structural defects in Si nc, such as dislocations and grain boundaries, are capable of trapping more carriers in a single solid state reaction Si nc.
Resonant and nonresonant patterns in forced oscillators
Authors: Marts Bradley , Hagberg Aric , Meron Ehud , Lin Anna L.
Published: September 2006

Uniform oscillations in spatially extended systems resonate with temporal periodic forcing within the Arnold tongues of single forced oscillators. The Arnold tongues are wedge-like domains in the parameter space spanned by the forcing amplitude and frequency, within which the oscillator’s frequency is locked to a fraction of the forcing frequency. Spatial patterning can modify these domains. We describe here two pattern formation mechanisms affecting frequency locking at half the forcing frequency. The mechanisms are associated with phase-front instabilities and a Turing-like instability of the rest state. Our studies combine experiments on the ruthenium catalyzed light-sensitive Belousov-Zhabotinsky reaction forced by periodic illumination, and numerical and analytical studies of two model systems, the FitzHugh-Nagumo model and the complex Ginzburg-Landau equation, with additional terms describing periodic forcing.
Multimegawatt peak-power, single-transverse-mode operation of a 100μm core diameter, Yb-doped rodlike photonic crystal fiber amplifier
Authors: Brooks Christopher D. , Di Teodoro Fabio
Published: September 2006

The authors report on the performance of an Yb-doped, 100μm core rodlike photonic crystal fiber (PCF) used as the final amplifier in a gain-staged master-oscillator/power-amplifier source. From the PCF, they obtained 1-ns-long pulses of energy in excess of 4.3mJ, peak/average power ∼4.5MW∕42W, and spectral linewidth ∼20GHz. The PCF emitted a beam exhibiting near-Gaussian, single-transverse-mode profile of M2∼1.3.