bluuebunny/crossref_metadata_2025_split huggingface dataset:
Normal morphometry of fetal posterior fossa at midtrimester: brainstem–tentorium angle and brainstem–vermis angle
Authors: Ghi Tullio , Contro Elena , De Musso Francesca , Farina Antonio , Conturso Roberto , Bonasoni Paola , Salsi Ginevra , Youssef Aly , Rizzo Nicola , Pilu Gianluigi 
Published: April 2012

ABSTRACTObjectiveTo standardize the evaluation of normal tentorium insertion and normal rotation of the cerebellar vermis over the brainstem, using two novel measurements: the brainstem–tentorium angle (BT angle) and the brainstem–vermis angle (BV angle). We also aimed to test the reproducibility of these measurements.MethodsProspective observational study including normal fetuses at routine anomaly scan with confirmed normal follow‐up. Three‐dimensional volumes of the fetal head were acquired starting from standard trans‐cerebellar views. In the sagittal plane, obtained by multiplanar reconstruction, the angle between the brainstem and the tentorium insertion in the fetal skull, and between the brainstem and the lower edge of the vermis were measured twice by two independent operators. Intraobserver and interobserver variations were calculated.ResultsEighty cases were included. The estimated BT and BV angles lie in a wide interval among normal midtrimester fetuses with a median value (min–max) of 25.65 (20.13–47.39) and 9.29 (3.87–19.36) respectively. Intraobserver and interobserver variation were good for both measurements.ConclusionThe BT and BV angle may be of help in assessing the fetal posterior fossa at midgestation and gives a standardized and reproducible measurement of normal tentorium insertion and normal rotation of the cerebellar vermis over the brainstem. © 2012 John Wiley & Sons, Ltd.
Straddling Two Geographic Regions: the Impact of Place of Origin and Destination on Return Migration Intentions in China
Authors: Piotrowski Martin , Tong Yuying 
Published: April 2012

ABSTRACTUsing data from a destination sample of labour migrants (N = 1,100) from China's Pearl River Delta, we develop and empirically evaluate a model of return migration intentions over multiple time horizons. We argue that return migration involves a complex decision‐making process whereby migrants, who are situated in a trans‐region social space spanning migration origin and destination areas, are influenced by economic and non‐economic factors in these distinct settings. Migrants weight the value of factors in both geographic regions and have shifting ideas about their future settlement. Results show that both economic and non‐economic factors operate in two distinct geographic spaces. Economic factors related to destination earning ability operate mainly in short time horizons. Also, migrants are sensitive to the economic situation of the origin household. Non‐economic factors related to child's location at origin and the migrants' living situation at destination are also significant, especially over long time horizons. Copyright © 2012 John Wiley & Sons, Ltd.
Laser driven dynamics of a quantum dot coupled to phonons: Dependence of the reappearance of Rabi rotations on the pulse length and shape
Authors: Vagov A. , Glässl M. , Croitoru M. D. , Axt V. M. , Machnikowski P. , Kuhn T. 
Published: April 2012

AbstractWe study the dynamics of a semiconductor quantum dot coupled to phonons and laser light in the limit of strong electronic confinement. Using real time path integrals our numerical results are nonperturbative with respect to both, the carrier‐light and the carrier‐phonon coupling. As it is known the damping of Rabi rotations is a non‐monotonic function of the pulse area.Here, we analyze how pulse parameters affect the resulting decay‐reappearance of Rabi rotations, which arises from the resonant nature of carrier‐phonon coupling. For longer pulses, the maximal reduction of the amplitude of Rabi rotations is shifted to higher pulse areas. In addition, for Gaussian pulses the reappearance rate is significantly reduced compared to rectangular profiles. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electron correlation effects on multimode Peierls distortion in the two‐dimensional electron‐lattice system
Authors: Matsumoto Yuki , Terai Akira 
Published: April 2012

AbstractThe electron correlation effects on the multimode Peierls (MMP) state in the Peierls Hubbard model on the two‐dimensional square lattice with the half‐filled electronic band is investigated, taking account of the on‐site interaction (U) and the nearest neighbor interaction (V), by using the variational Monte Carlo method based on the Gutzwiller wave function.The Peierls distortion amplitude is enhanced as U is increased, showing the first‐order phase transition from the MMP state to the antiferromagnetic state. The Peierls distortion amplitude is also enhanced by V. The first‐order phase transition from the MMP state to the charge‐ordered state occurs at a critical value of V. There is no coexistence of the Peierls distortion and the charge order. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Improvements to elementary children's epistemic understanding from sustained argumentation
Authors: Ryu Suna , Sandoval William A. 
Published: April 2012

AbstractThe aim of this study was to assess whether and how a sustained instructional focus on argumentation might improve children's understanding and application of key epistemic criteria for scientific arguments. These criteria include the articulation of clear, coherent causal claims, and the explicit justification of such claims with appropriate evidence. We show a mixed‐age class of 8–10‐year‐old children improved in their ability to both construct and evaluate arguments, especially in the ways they met evidentiary criteria. We locate these improvements in their classroom's development of a number of norms for “good arguments'' that focused on evidentiary standards. We summarize how students' appropriation of specific norms around showing evidence and justifying evidentiary relations produced these outcomes. We frame these findings in terms of their implications for promoting argumentation in classrooms, children's capacities for engaging in such argumentation, and in relation to the development of informed views about the nature of professional science. © 2012 Wiley Periodicals, Inc. Sci Ed 96:488–526, 2012
Model predictive control of a wind turbine using short‐term wind field predictions
Authors: Spencer Martin D. , Stol Karl A. , Unsworth Charles P. , Cater John E. , Norris Stuart E. 
Published: April 2012

ABSTRACTAs wind turbines become larger and hence more flexible, the design of advanced controllers to mitigate fatigue damage and optimise power capture is becoming increasingly important. The majority of the existing literature focuses on feedback controllers that use measurements from the turbine itself and possibly an estimate or measurement of the current local wind profile. This work investigates a predictive controller that can use short‐term predictions about the approaching wind field to improve performance by compensating for measurement and actuation delays.Simulations are carried out using the FAST aeroelastic design code modelling the NREL 5 MW reference turbine, and controllers are designed for both above rated and below rated wind conditions using model predictive control. Tests are conducted in various wind conditions and with different future wind information available. It is shown that in above rated wind conditions, significant fatigue load reductions are possible compared with a controller that knows only the current wind profile. However, this is very much dependent on the speed of the pitch actuator response and the wind conditions. In below rated wind conditions, the goals of power capture and fatigue load control were considered separately. It was found that power capture could only be improved using wind predictions if the wind speed changed rapidly during the simulation and that fatigue loads were not consistently reduced when wind predictions were available, indicating that wind predictions are of limited benefit in below rated wind conditions. Copyright © 2012 John Wiley & Sons, Ltd.
Biological Evolution on Display: an Approach to Evolutionary Issues Through a Museum
Authors: Falchetti Elisabetta M. 
Published: April 2012

AbstractBiological museums can promote interest in evolution and contribute to its understanding. Modern exhibitions generally emphasize the main concepts of evolutionary theory: biodiversity and adaptation. In 2009 at the Zoological Museum of Rome, to celebrate Charles Darwin, a pilot didactic project was carried out for schools and the general public in order to involve people in evolutionary issues, to stimulate interest and at constructing knowledge about evolution. An exhibition consisting of exhibits and laboratory settings was created. The thematic contexts of the exhibition and the practical experiences were aimed at facing some epistemological obstacles that influence the understanding of evolution and at constructing some “framing concepts” that, on the contrary, could facilitate it. The communicative and didactic strategies were all participative and interactive, based on the personal questioning and restructuring of preexisting knowledge. Behaviors, conversations, and comments by the participants were monitored in order to record any possible change of ideas, interests, attitudes, and learning.
China’s Megacities: Risks, Opportunities and Environmental Health
Authors: Jahn Heiko J. 
Published: April 2012

Einleitung
Megastädte in China befinden sich im Wandel, geprägt durch rasantes ökonomisches und Bevölkerungswachstum. Die Regier- und Steuerbarkeit sind beeinträchtigt und infrastrukturelle Maßnahmen, z.B. zum Schutz der Umwelt, können nicht in gleichem Maße mithalten. Umweltverschmutzung mit substantiellen Gesundheitsgefährdungen ist die Folge. Gesetze/Bestimmungen zum Umweltschutz sollten auf allen Ebenen (Zentralregierung bis Stadteilebene) umgesetzt werden, um die Stadtgesundheit zu verbessern.
Gastroesophageal reflux disease and tympanoplasty surgical outcome: is there a relationship?
Authors: Habesoglu T E , Habesoglu M , Kalaycik C , Tek A , Surmeli M , Egeli E 
Published: April 2012

AbstractObjective:To investigate the possible clinical relationship between gastroesophageal reflux disease and the type one tympanoplasty surgical outcomes of adults with chronic otitis media, by using a simple, cost-effective, reliable questionnaire and physical findings.Methods:Fifty-two of 147 patients undergoing type one tympanoplasty were studied. Gastroesophageal reflux disease symptoms were evaluated using the Frequency Scale for the Symptoms of Gastroesophageal Reflux Disease questionnaire. Laryngoscopic physical findings of laryngopharyngeal reflux were evaluated using the Reflux Finding Score. A successful outcome was defined as an intact tympanic membrane. Correlations between the two assessment tool results and the patient's surgical success were calculated.Results:The gastroesophageal reflux disease questionnaire score was significantly higher in patients with unsuccessful tympanic membrane closure (group one) than in patients with successful closure (group two) (p < 0.05). The Reflux Finding Score was also significantly higher in group one than group two (p < 0.05). There was a significant positive relationship between the gastroesophageal reflux disease questionnaire score and the Reflux Finding Score (p < 0.01).Conclusion:Gastroesophageal reflux disease may be a significant prognostic factor for tympanoplasty failure. Therefore, reflux investigation may be important during the treatment of chronic otitis media, and positive cases may need reflux treatment as well as ear disease treatment.
Self-injected petawatt laser-driven plasma electron acceleration in 1017 cm−3 plasma
Authors: WANG X. , ZGADZAJ R. , YI S. A. , KHUDIK V. , HENDERSON W. , FAZEL N. , CHANG Y.-Y. , KORZEKWA R. , TSAI H.-E. , PAI C.-H. , LI Z. , GAUL E. , MARTINEZ M. , DYER G. , QUEVEDO H. , BERNSTEIN A. , DONOVAN M. , SHVETS G. , DITMIRE T. , DOWNER M. C. 
Published: April 2012

AbstractWe report production of a self-injected, collimated (8 mrad divergence), 600 pC bunch of electrons with energies up to 350 MeV from a petawatt laser-driven plasma accelerator in a plasma of electron density ne = 1017 cm−3, an order of magnitude lower than previous self-injected laser-plasma accelerators. The energy of the focused drive laser pulse (150 J, 150 fs) was distributed over several hot spots. Simulations show that these hot spots remained independent over a 5 cm interaction length, and produced weakly nonlinear plasma wakes without bubble formation capable of accelerating pre-heated (~1 MeV) plasma electrons up to the observed energies. The required pre-heating is attributed tentatively to pre-pulse interactions with the plasma.
Technology developments for a large-format heterodyne MMIC array at W-band
Authors: Sieth Matthew , Church Sarah , Lau Judy M. , Voll Patricia , Gaier Todd , Kangaslahti Pekka , Samoska Lorene , Soria Mary , Cleary Kieran , Gawande Rohit , Readhead Anthony C.S. , Reeves Rodrigo , Harris Andrew , Neilson Jeffrey , Tantawi Sami , Van Winkle Dan 
Published: April 2012

We report on the development of W-band (75–110 GHz) heterodyne receiver technology for large-format astronomical arrays. The receiver system is designed to be both mass producible, so that the designs could be scaled to thousands of receiver elements, and modular. Most of the receiver functionality is integrated into compact monolithic microwave integrated circuit (MMIC) amplifier-based multichip modules. The MMIC modules include a chain of InP MMIC low-noise amplifiers, coupled-line bandpass filters, and sub-harmonic Schottky diode mixers. The receiver signals will be routed to and from the MMIC modules on a multilayer high-frequency laminate, which includes splitters, amplifiers, and frequency triplers. A prototype MMIC module has exhibited a band-averaged noise temperature of 41 K from 82 to 100 GHz and a gain of 29 dB at 15 K, which is the state-of-the-art for heterodyne multichip modules.
U.S. and USSR to cooperate on auroral studies
Authors: Anonymous  
Published: April 2012

A joint U.S.‐USSR scientific program will study the structure and form of auroral ‘substorms.’ The NSF has granted $24,600 to the University of Alaska, College, to permit the university's Geophysical Institute to carry out the U.S. portion of the program The Geophysical Institute will cooperate with the Institute of the Physics of the Earth (IPE) of the Academy of Sciences of the USSR in the program.Auroral substorms are magnetic storms that occur throughout the earth's outer atmosphere at high latitudes. They cause radio blackouts, clutter on radar, and brilliant displays of the aurora borealis.
IAU Symposium
Authors: Anonymous  
Published: April 2012

The International Astronomical Union Symposium No. 47, ‘The Moon,’ will be held March 22–26, 1971 at The School of Physics, University of Newcastle upon Tyne, England.Sessions will be devoted to the following fundamental areas of lunar science: the figure of the moon, magnetic fields and the moon, age and evolution of the lunar surface, thermal and electrical properties of lunar rocks and solid state physics, internal constitution and physiochemical processes in the interior, origin and motion of the moon, and mineralogy and petrology of lunar rocks.
Lockheed electronics gets earth resources contract
Authors: Anonymous  
Published: April 2012

An $800.000 NASA Manned Spacecraft Center contract to provide scientific and technical support services for the Earth Resources Laboratory has been awarded to Lockheed Electronics Co., Inc.Lockheed will assist the laboratory, which is located at NASA's Mississippi Test Facility in Bay St. Louis, in developing applications for information acquired from Gemini and Apollo missions, aircraft and ground stations, plus data to be obtained from future programs such as Earth Resources Technology Satellites (ERTS) and the manned Skylab.
Measuring coastal wave energy
Authors: Anonymous  
Published: April 2012

Development of a long‐term measure of unidirectional effective coastal wave energy has been conducted by W.F. Tanner and F.W. Stapor of the Florida State University Geology Department. Previously, coastal wave energy was measured directly, on a short‐term basis (thereby including non‐effective components, which make up 99% or more of the total), or was estimated from various rules‐of‐thumb.Stapor used bathymetric charts to compartmentalize selected reaches of low‐to‐moderate energy sandy coast, and to determine the volume of sand eroded and deposited in each compartment. Leakage was relatively slight.
Data Center for EROS Program
Authors: Anonymous  
Published: April 2012

A significant step forward for the Department of the Interior's EROS (Earth Resources Observation Systems) program—directed by the U.S. Geological Survey was announced recently. Interior Secretary Rogers C.B. Morton said that an architect‐engineer contract for an EROS Data Center, to be located in the vicinity of Sioux Falls, South Dakota, has been successfully negotiated. Total cost of the center is estimated at $4.8 million, and is scheduled for completion in mid‐1972.‘The Center at Sioux Falls,’ Secretary Morton said, ‘will be a key installation in the use of remote‐sensor data obtained from aircraft and spacecraft for purposes of resources and environmental surveys. Under the management of the Geological Survey, it will be a central repository where data will be received and processed.
Modeling techniques in water resources systems
Authors: Anonymous  
Published: April 2012

An International Symposium on Modeling Techniques in Water Resources Systems will be held in Ottawa, Ontario, Canada, May 9–12, 1972. The symposium will bring together international experts from all disciplines involved with the development and application of mathematical modeling techniques to the planning, operation, and management of water resources systems.Approximately 70% of the papers will be invited; the rest will be unsolicited. Participation in the symposium will be by invitation only. For further information concerning the symposium write Asit K. Biswas, Chairman, Organizing Committee, International Symposium on Modeling Techniques in Water Resources Sector, Department of Fisheries and Forestry, Ottawa, Ontario, Canada.
Gordon Research Conferences
Authors: Anonymous  
Published: April 2012

The Gordon Research Conferences, international symposia on significant developments in the most active areas of basic research, will hold seventy sessions this summer. Scheduled to open June 14, the conferences will be held at seven sites in New Hampshire and Wisconsin and will continue through September 3.The meetings, each devoted exclusively to a single subject, are limited to about 100 participants and last one week each. More than 7000 scientists will participate this year from the U.S. and abroad.
Rheology of the mantle
Authors: O'Connell Richard J. 
Published: April 2012

There have been two main avenues of investigation of the rheology of the mantle: theoretical and laboratory studies of the mechanical behavior of solids and direct estimates obtained by comparing geologic observations with model calculations in which rheological parameters are the principal variables. Studies of large‐scale mantle flow, such as convection, might also put some constraints on mantle rheology, although at the present better knowledge of the rheology is needed to specify suitable models for investigation.The main advances of the last 4 years in our understanding of mantle rheology have been in the realization that the lower mantle may be less resistant to creep than was previously believed and in the realization and preliminary investigation of the complexities of the convection problem.
Research in physics at Aberdeen
Authors: Anonymous  
Published: April 2012

Aberdeen University in Aberdeen, Scotland, attempts to make the most of the advantages it has in special competence and in geographical situation, while minimizing the disadvantages incurred from a peripheral position among British universities. They are weak in research student numbers but for individual research students this has the compensating advantage that he is likely to receive more careful supervision from senior staff than if he were working in a large team. Additionally, while heavy expenditure on large‐scale apparatus such as particle accelerators would be impracticable, the department is well equipped, notably in workshop and electronics services; and the university library is strong.The main research effort is in pure physics but there is considerable emphasis also on geophysics and radio astronomy.
DSDP scientists discover how Panama Isthmus was formed
Authors: Anonymous  
Published: April 2012

Recent findings by the Deep Sea Drilling Project explaining how the Isthmus of Panama was formed were announced at the AGU Annual Meeting in April by Tjeerd H. van Andel and G. Ross Heath of Oregon State University's Department of Oceanography as one of the principal results of Leg 16 of the Deep Sea Drilling Project. The cruise began in Cristobal, Panama, on February 5 and ended in Honolulu, Hawaii, on March 30.During the first part of drilling vessel Glomar Challenger's sixteenth cruise, the shipboard scientists tested a hypothesis developed recently at Oregon State University and Lamont‐Doherty Geological Observatory of Columbia University. On the basis of geophysical observations, this hypothesis suggests that 10 to 15 million years ago an ocean ridge extended eastward from the present position of the Galapagos Islands. This ridge split lengthwise as a rift zone grew from the eastern end. The southern half remained at its position near the equator while the northern half broke in several pieces that began a slow drift northward in response to thermal currents deep in the earth.
Unique radar system used for mapping uncharted regions in South America
Authors: Anonymous  
Published: April 2012

A sophisticated airborne radar system that can ‘see’ at night and through clouds is being used by the Aero Service Division of Litton Industries to map and create photo‐like images of uncharted jungle regions of South America.An aerial search for natural resources over 80,000 square miles of the cloud‐covered Orinoco basin in Venezuela using a Side‐Looking Airborne Radar (SLAR) system installed aboard a high‐altitude jetliner is being conducted by Litton Aero Service in association with Goodyear Aerospace Corp. Plans for a second SLAR survey will begin in May and cover 600,000 square miles of the Brazilian Amazon basin, an area onefifth the size of the United States. This project will be conducted in association with LASA, Brazil's leading civil engineering and resources firm. The two contracts amount to about $6.5 million.
New method aimed at detecting nickel
Authors: Anonymous  
Published: April 2012

A new method that can be used to detect nickel and other elements in the earth's crust, and possibly on the ocean floor and on the surface of other planets, has been revealed by scientists of the U.S. Geological Survey.USGS physicist and project leader Frank Senftle, reported results from USGS laboratory experiments in which radiation signals given off by nickel under neutron bombardment were quickly identified. Senftle and other USGS scientists are working with D. Duffey (University of Maryland) and P. Wiggins (U.S. Naval Academy). They are using an unconventional neutron activation technique ‘which appears to be more sensitive than ordinary neutron activation for some elements.’