bluuebunny/crossref_metadata_2025 huggingface dataset:
Eine Normierungsstudie eines modifizierten Trail Making Tests im deutschsprachigen Raum
Authors: Rodewald Katlehn , Bartolovic Marina , Debelak Rudolf , Aschenbrenner Steffen , Weisbrod Matthias , Roesch-Ely Daniela
Published: March 2012

Der Trail Making Test (TMT) ist ein international weit verbreitetes Verfahren, das z. B. zur Untersuchung von Patienten mit erworbenen Hirnschädigungen eingesetzt wird. Die Performanz im TMT wird mit unterschiedlichen neuropsychologischen Domänen, wie z. B. Aufmerksamkeit und Exekutivfunktionen, in Verbindung gebracht. Trotz der häufigen Anwendung im klinischen Alltag liegen bisher keine deutschsprachigen Normen für einen umfassenden Altersrange vor. Die vorliegende Untersuchung hat daher den Einfluss von Alter und Bildung auf die Bearbeitungszeit im TMT bei deutschsprachigen Erwachsenen im Alter zwischen 18 und 85 Jahren erfasst und analysiert. Ausschlusskriterien bildeten neurologische oder psychiatrische Erkrankungen, die Beeinträchtigung des Blickfeldes bzw. der Sehfähigkeit, die motorische Beeinträchtigung der Arme und Hände sowie Drogen- oder Alkoholmissbrauch. Die Stichprobe ist in vier Altersgruppen aufgeteilt: 18 – 34 Jahre (n = 148), 35 – 49 Jahre (n = 111), 50 – 64 Jahre (n = 93) und 65 – 84 Jahre (n = 53). Hinsichtlich der Bildung wurden zwei Gruppen gebildet: niedriges bis mittleres Bildungsniveau ( ≤ 12 Jahre formale Bildung) und höheres Bildungsniveau ( ≥ 12 Jahre formale Bildung). Signifikante Korrelationen zwischen den demografischen Variablen und den Bearbeitungszeiten im TMT-A bzw. TMT-B zeigen, dass sowohl Alter als auch Bildung mit der Leistung im TMT korrelieren (p < .01). Post hoc Analysen machen deutlich, dass sich dabei alle Altersgruppen voneinander unterscheiden. Die Ergebnisse für die Bearbeitungszeit stehen in Einklang mit früheren Normierungsstudien, die ebenfalls Alter und Bildung als die bedeutsamsten Moderatoren für die Leistung im TMT identifiziert hatten.
Klinisch-neuropsychologischer Fallbericht: A. T. B.
Authors: Kringler Wolfgang
Published: March 2012

Der Fallbericht beschreibt die Situation einer jungen Studentin nach schwerem Schädel-Hirn-Trauma und die lebensentscheidende Bedeutung, die dem neuropsychologischen Bericht zukommt. Während eines Rehabilitationsaufenthaltes wurden neuropsychologische Befunde dokumentiert, die im Entlassungsbericht zu einem Abraten von der Fortsetzung ihres Pharmaziestudiums und der Darstellung einer schwer beeinträchtigen Person führten. Auf Initiative der Familie wurde eine Zweitmeinung eingeholt, die sich von der vorhergehenden Einschätzung deutlich unterschied. Nicht mit erhobenem Zeigefinger, sondern unter Ausbildungs- sowie ethischen Gesichtspunkten soll die Notwendigkeit zu hoher Sorgfaltsleistung, Nützlichkeit und Professionalität bei der neuropsychologischen Diagnostik und Therapie dargestellt werden.
Arc‐continent collision and orocline formation: Closing of the Central American seaway
Authors: Montes Camilo , Bayona G. , Cardona A. , Buchs D. M. , Silva C. A. , Morón S. , Hoyos N. , Ramírez D. A. , Jaramillo C. A. , Valencia V.
Published: March 2012

Closure of the Central American seaway was a local tectonic event with potentially global biotic and environmental repercussions. We report geochronological (six U/Pb LA‐ICP‐MS zircon ages) and geochemical (19 XRF and ICP‐MS analyses) data from the Isthmus of Panama that allow definition of a distinctive succession of plateau sequences to subduction‐related protoarc to arc volcaniclastic rocks intruded by Late Cretaceous to middle Eocene intermediate plutonic rocks (67.6 ± 1.4 Ma to 41.1 ± 0.7 Ma). Paleomagnetic analyses (24 sites, 192 cores) in this same belt reveal large counterclockwise vertical‐axis rotations (70.9° ± 6.7°), and moderate clockwise rotations (between 40° ± 4.1° and 56.2° ± 11.1°) on either side of an east‐west trending fault at the apex of the Isthmus (Rio Gatun Fault), consistent with Isthmus curvature. An Oligocene‐Miocene arc crosscuts the older, deformed and segmented arc sequences, and shows no significant vertical‐axis rotation or deformation. There are three main stages of deformation: 1) left‐lateral, strike‐slip offset of the arc (∼100 km), and counterclockwise vertical‐axis rotation of western arc segments between 38 and 28 Ma; 2) clockwise rotation of central arc segments between 28 and 25 Ma; and 3) orocline tightening after 25 Ma. When this reconstruction is placed in a global plate tectonic framework, and published exhumation data is added, the Central American seaway disappears at 15 Ma, suggesting that by the time of northern hemisphere glaciation, deep‐water circulation had long been severed in Central America.
Momentum budget of the migrating diurnal tide in the Whole Atmosphere Community Climate Model at vernal equinox
Authors: Lu X. , Liu H.‐L. , Liu A. Z. , Yue J. , McInerney J. M. , Li Z.
Published: March 2012

The momentum budget of the migrating diurnal tide (DW1) at the vernal equinox is studied using the Whole Atmosphere Community Climate Model, version 4 (WACCM4). Classical tidal theory provides an appropriate first‐order prediction of the DW1 structure, while gravity wave (GW) forcing and advection are the two most dominant terms in the momentum equation that account for the discrepancies between classical tidal theory and the calculation based on the full primitive equations. It differs from the conclusion by McLandress (2002a) that the parameterized GW effect is substantially weaker than advection terms based on the Canadian Middle Atmosphere Model (CMAM). In the region where DW1 maintains a large amplitude, GW forcing in the wave breaking region always damps DW1 and advances its phase. The linear advection largely determined by the latitudinal shear of the zonal mean zonal wind makes a dominant contribution to the phase change of DW1 in the zonal wind compared to the GW forcing and nonlinear advection. However, nonlinear advection is more important than GW forcing and linear advection in modulating the amplitude and phase of DW1 in the meridional wind. The DW1 amplitudes in temperature and winds are smaller than the TIMED observations, suggesting that GW forcing is overestimated in the WACCM4 and results in a large damping of DW1.
President's message: We must remain committed to scientific integrity
Authors: McPhaden Michael
Published: March 2012

During the third week of February our global community of Earth and space scientists witnessed the shocking fall from grace of an accomplished AGU member who betrayed the principles of scientific integrity. In doing so he compromised AGU's credibility as a scientific society, weakened the public's trust in scientists, and produced fresh fuel for the unproductive and seemingly endless ideological firestorm surrounding the reality of the Earth's changing climate. Peter Gleick resigned as chair of AGU's Task Force on Scientific Ethics on 16 February, prior to admitting in a blog post that he obtained documents from the Heartland Institute under false pretenses. His transgression cannot be condoned, regardless of his motives. It is a tragedy that requires us to stop and reflect on what we value as scientists and how we want to be perceived by the public. Here are a few things that come immediately to mind:
AGU honors 79 geophysicists during 2011 awards cycle
Authors: Paredes Beth
Published: March 2012

At the 2011 Fall Meeting, AGU honored 79 esteemed geophysicists for their landmark achievements and transformational discoveries, highlighting those who have pioneered new frontiers of scientific knowledge with dedication, commitment, and leadership. Sixty individuals widely recognized as experts in their fields of research were honored as the 2011 class of AGU Fellows. These scientists, who share a lifelong commitment to understanding how the world works and are dedicated to making it a better place, were nominated by their colleagues for spurring major paradigm shifts and innovating breakthrough discoveries in Earth and space sciences. Six Union awardees received recognition for their vision and leadership, for furthering education in the Earth and space sciences, and for outstanding and sustained achievements in science journalism. In addition, AGU presented its inaugural Climate Communication Prize, for outstanding contributions to scientific literacy and public awareness about the urgent problem of climate change.
Middle and high school students shine
Authors: Asher Pranoti , Saltzman Jennifer
Published: March 2012

Middle and high school students participating in after‐school and summer research experiences in the Earth and space sciences are invited to participate in AGU's Bright Students Training as Research Scientists (Bright STaRS) program. The Bright STaRS program provides a dedicated forum for these students to present their research results to the scientific community at AGU's Fall Meeting, where they can also learn about exciting research, education, and career opportunities in the Earth and space sciences. Last year's program included 33 abstracts from middle and high school students involved with the Stanford University School of Earth Sciences; Raising Interest in Science and Engineering summer internship program sponsored by the Office of Science Outreach at Stanford; Lawrence Hall of Science at the University of California, Berkeley; the University of California, Santa Cruz; California Academy of Science; San Francisco State University; the University of Arizona; and the National Oceanic and Atmospheric Administration's Gulf of the Farallones National Marine Sanctuary. Their work spanned a variety of topics ranging from structural geology and paleontology to environmental geology and polar science. Nearly 100 Bright STaRS students presented their research posters on Thursday morning (8 December) of the Fall Meeting and had a chance to interact with scientists, AGU staff, and other meeting attendees.
Families learn what it's like to be a geoscientist astronaut
Authors: Adamec Bethany Holm
Published: March 2012

Astronaut and AGU member Andrew Feustel delivered the 2011 Public Lecture on Sunday, 4 December. Feustel gave a fun and engaging talk full of amazing photos about his two space missions: STS‐125, during which he and his fellow crew members extended the life of the Hubble Space Telescope, and STS‐134, the space shuttleEndeavour's final mission, which delivered the Alpha Magnetic Spectrometer (AMS) to the International Space Station (ISS). AMS is a state‐of‐ the‐art instrument designed to study matter and the origin and structure of the universe. RegularEos readers will remember a July 2011 article aboutEos in space, complete with a photo of an issue of Eos floating in front of the ISS window (Eos, 92(28), 236, doi:10.1029/2011EO2800 08). As the enthusiastic AGU member who took that issue into space, Feustel spoke from the unique perspective of someone who was trained in the geosciences before becoming an astronaut. Thus, he discussed the role of astronauts as explorers of Earth from space as well as the importance of geological observations on the Moon and the exploration of the cosmos. To thank him for his dedication, AGU president Mike McPhaden joined more than 160 other attendees at the Public Lecture and presented Feustel with a framed picture of the article featuring Eos in space.
Editors and author resource centers actively used by attendees
Authors: Major Barbara
Published: March 2012

At the 2011 Fall Meeting, as in previous years, the Editors Resource Center located on the second floor of Moscone West was buzzing with activity: editors talking with other editors, collaborating with associate editors, speaking with authors, and meeting with students. In addition, several editors took part in “Meet the Editor” informal sessions, a new feature introduced for the 2011 meeting to strengthen the partnership between authors and editors. The map “Where are you from?” (see photo), outside the Editors Resource Center, drew the attention of many attendees who were eager to place their colored dots on the map. The Author Resource Center, located in the AGU Marketplace, became a hub for AGU veteran authors and potential authors alike. Staff were there to answer both editorial and technical questions, especially the most frequent one: What happens after my paper is accepted? The running slideshow that described all aspects of the AGU publications program sparked a myriad of questions, which AGU staff were happy to answer.
AGU donors and supporting members play role at Fall Meeting
Authors: Berwager Brent
Published: March 2012

More than 1800 of AGU's top donors attended the 2011 Fall Meeting, and many of them sought refuge in the newly improved donor lounges. To quietly recognize supporting members, the lounges offered quiet space to relax between sessions, enjoy refreshments, meet with other donors, or work. Supporting members and AGU donors of all levels played a bigger role than ever at the Fall Meeting. Through the generous support of longtime members and AGU supporters Bruce Tsurutani and Olga Verkhoglyadova, the Space Weather and Nonlinear Waves and Processes Prize was announced at the meeting and will be awarded for the first time at the 2013 Fall Meeting.
Tracking meltwater retention in Greenland
Authors: Balcerak Ernie
Published: March 2012

In Greenland, surface melt has increased significantly in area and intensity in recent years. Melting has increased in the accumulation area, normally a region of snow accumulation. This increase in meltwater can affect the ice sheet's mass balance and ice flow dynamics. When melt occurs on the surface, meltwater may trickle down through snow a short distance vertically and then refreeze, forming thin ice layers, it may penetrate underlying snow and create pools, or it may migrate horizontally and become runoff. The fate of meltwater is not well understood because the processes of meltwater infiltration into an ice sheet have not been well measured.
Live-cell visualization of transmembrane protein oligomerization and membrane fusion using two-fragment haptoEGFP methodology
Authors: Quinn Derek J. , McFerran Neil V. , Nelson John , Duprex W. Paul
Published: March 2012

Protein interactions play key roles throughout all subcellular compartments. In the present paper, we report the visualization of protein interactions throughout living mammalian cells using two oligomerizing MV (measles virus) transmembrane glycoproteins, the H (haemagglutinin) and the F (fusion) glycoproteins, which mediate MV entry into permissive cells. BiFC (bimolecular fluorescence complementation) has been used to examine the dimerization of these viral glycoproteins. The H glycoprotein is a type II membrane-receptor-binding homodimeric glycoprotein and the F glycoprotein is a type I disulfide-linked membrane glycoprotein which homotrimerizes. Together they co-operate to allow the enveloped virus to enter a cell by fusing the viral and cellular membranes. We generated a pair of chimaeric H glycoproteins linked to complementary fragments of EGFP (enhanced green fluorescent protein) – haptoEGFPs – which, on association, generate fluorescence. Homodimerization of H glycoproteins specifically drives this association, leading to the generation of a fluorescent signal in the ER (endoplasmic reticulum), the Golgi and at the plasma membrane. Similarly, the generation of a pair of corresponding F glycoprotein–haptoEGFP chimaeras also produced a comparable fluorescent signal. Co-expression of H and F glycoprotein chimaeras linked to complementary haptoEGFPs led to the formation of fluorescent fusion complexes at the cell surface which retained their biological activity as evidenced by cell-to-cell fusion.
Diagnostic evaluation of a synthetic peptide derived from a novel antigen B subunit as related to other available peptides and native antigens used for serology of cystic hydatidosis
Authors: BARBIERI MARIELA , FERNÁNDEZ VERÓNICA , GONZÁLEZ GUALBERTO , LUACES VICTOR MARTINEZ , NIETO ALBERTO
Published: March 2012

A synthetic peptide (GU4) derived from an antigen B (AgB) subunit was serologically compared with crude antigen (HCFA); immunopurified AgB and antigen 5 (Ag5), and two other synthetic peptides, for diagnosis of human cystic hydatidosis. GU4 was derived from the sequence of AgB/2, the novel AgB subunit described by us. The other two peptides: 65 (AgB mimotope) and 89–122 (Ag5 mimotope), were described by others. Antigens B and 5 showed higher diagnostic sensitivity than corresponding peptides. All sera reacting with peptides 89–122 and GU4 also reacted with 65. The latter provided three to four times higher sensitivity than the former two peptides, but 30% lower specificity. The diagnostic efficiency of AgB (82%) was higher than those of Ag5 (74%) and HCFA (71%). Interestingly, 89–122 only reacted with hydatid sera, some of which did not react with AgB. Considering positive those reacting with 89–122 or AgB, sensitivity increases from 77% (with AgB) to 82% (combined), while specificity is the same as with AgB (86%). Our results suggest that hydatid serology may be improved by: a) combining several defined antigens (including synthetic peptides), b) design of new E. granulosus‐specific mimotopes, which react with the false negative sera (16/90; 18%).
Thickness-dependent magnetization reversal behavior of lithographic IrMn/Fe ring structures
Authors: Hou Yu-feng , Krishnan Kannan M.
Published: March 2012

We systematically studied the effect of exchange bias (EB) on the magnetization reversal behavior in lithographic IrMn/Fe rings and their unbiased Fe counterparts, with the thickness of the Fe layer, tFe, varying from 10 to 80 nm. For unbiased and exchange biased rings, an evolution in the shape of the hysteresis loop from single-step to double-step is observed as tFe increases. However, for EB rings, this transition happens at larger thickness, which is attributed to the uniaxial anisotropy induced by exchange bias in the Fe layer. The strength of the magnetic anisotropy induced by exchange bias is investigated by fitting the angular dependence of the exchange bias field Heb at different Fe thickness.
Manipulations of vibrating micro magnetic particle chains
Authors: Li Yan-Hom , Sheu Shih-Tsung , Pai Jay-Min , Chen Ching-Yao
Published: March 2012

We investigate the motion of a micro-chain consisting of several magnetic particles. The chain is firstly formed by a uniform directional field, and then manipulated by a vibrating field. We demonstrate where the chain appears to display distinct behaviors, from rigid body vibrations, bending distortions to breaking failures, by increasing either the chain’s length or vibrating amplitude. In addition, the vibrating chain can be successfully driven forward, mimicking a micro-swimmer by connecting particles of different sizes.
Exchange bias effect of Ge1−xMnxTe with antiferromagnetic MnTe and MnO materials
Authors: Lim S. T. , Hui Lu , Bi J. F. , Liew T. , Teo K. L.
Published: March 2012

We have performed exchange biasing of ferromagnetic GeMnTe by an either MnTe or MnO antiferromagnetic overlayer. In the case of GeMnTe/MnTe bilayer, we have observed only an enhancement of coercivity. While in GeMnTe/MnO bilayer, both the hysteresis loop-shift and enhancement of the coercivity are exhibited. The Curie temperature (Tc) and the blocking temperature (TB) of GeMnTe/MnO bilayer are 60 and 20 K, respectively as compared to the Tc ∼ 95 K of a GeMnTe single layer.
Structural, magnetic, and electron transport properties of MnBi:Fe thin films
Authors: Kharel P. , Li X. Z. , Shah V. R. , Al-Aqtash N. , Tarawneh K. , Sabirianov R. F. , Skomski R. , Sellmyer D. J.
Published: March 2012

The structural, magnetic, and electron transport properties of Mn55−xFexBi45 (x = 0, 2, 4, 5, 8, 11, 13, 16) films prepared by multilayer deposition and annealing using e-beam evaporation have been investigated. Fe doping has produced a significant change in the magnetic properties of the samples including the decrease in saturation magnetization and magnetocrystalline anisotropy and increase in coercivity. Although the magnetization shows a smooth decrease with increasing Fe concentration, the coercivity jumps abruptly from 8.5 kOe to 22 kOe as Fe content changes from 4% to 5%, but the change in coercivity is small as the concentration goes beyond 5%. The temperature dependence of resistivity shows that the samples with low Fe concentration (≤4%) are metallic, but the resistivity increases unexpectedly as the concentration reaches 5%, where the resistance increases with decreasing temperature below 300 K. First-principle calculations suggest that the observed magnetic properties can be understood as the consequences of competing ferromagnetic and antiferromagnetic exchange interactions between the interstitial atom and the rest of the MnBi lattice.
Spin-bias modulated Kondo effect in an interacting quantum dot
Authors: Li Yuan , Jalil M. B. A. , Tan Seng Ghee
Published: March 2012

We investigate the transport properties of an interacting quantum dot modulated by spin bias by means of the Keldysh nonequilibrium Green’s function method. The charge and spin differential conductance (Gc and Gs, respectively) are calculated for three kinds of spin-bias configurations. Our calculations show the presence of conductance plateaus and steps in Gc and Kondo peaks in Gs. These conductance characteristics may be explained by considering the Kondo peaks in the density of states. By analyzing the different spin and charge conductance at low temperature, one can characterize the configuration and magnitude of spin accumulation in the leads.
Giant magnetocaloric effect of Mn0.92Ba0.08As thin film grown on Al2O3(0001) substrate
Authors: Duc Dung Dang , Anh Tuan Duong , Van Thiet Duong , Shin Yooleemi , Cho Sunglae
Published: March 2012

The epitaxial Mn0.92Ba0.08As thin film was grown on Al2O3(0001) substrate by molecular beam epitaxy. The Curie temperature (TC) around 350 K was enhanced with the addition of Ba, compared to that of bulk MnAs (TC ∼ 318 K). We have observed the linear resistivity versus the square of temperature and high negative magnetoresistance near Curie temperature. Moreover, the giant magnetocaloric effect was found with maximum magnetic entropy change, 65 J/kgK, around room temperature at 5 T.
Tuning the magnetic ground state in LixNi(2-x)O2
Authors: Sow Chanchal , Kumar P. S. Anil
Published: March 2012

The experimental determination of the magnetic ground state of triangular lattice anti-ferromagnet LiNiO2 is an intriguing problem as the system is prone to be Li deficient. We have been successful in preparing nearly stoichiometric LiNiO2 showing an anti-ferromagnetic ground state with an ordering temperature ∼12 K. As the Li deficiency increases the sample exhibits spin glass behavior evidenced by a shift in the spin glass freezing temperature as a function of frequency in the ac susceptibility studies. As the Li deficiency crosses a critical limit, the sample becomes ferromagnetic in nature. We are able to tune the ferromagnetic transition temperature up to 240 K by varying the Li content. Finally, we have constructed a magnetic phase diagram.
Stabilization of input impedance for wireless power supply circuit
Authors: Misawa Takahiro , Sato Tadakuni , Takura Tetsuya , Sato Fumihiro , Matsuki Hidetoshi
Published: March 2012

A wireless power supply transmits electrical energy from a power source to a load without the use of a connecting wire. There are a number of wireless power supply techniques including electromagnetic induction, electromagnetic radiation, and electrical conduction. Here, we have investigated methods that use electromagnetic induction. Typically, for electromagnetic induction, we assume that the load resistance will fluctuate during battery charging due to variations in the battery voltage. Therefore, to stabilize the electrical power supply, a steady input impedance of the transmission circuit is preferable such that the influence of load resistance fluctuations is minimized. To this end, we suggest a “series-parallel resonant circuit” for the transmission circuit that has this characteristic.
The Volleben effect in magnetic superconductors Dy1–xYxRh4B4 (x = 0.2, 0.3, 0.4, and 0.6)
Authors: Dmitriev V. M. , Terekhov A. V. , Zaleski A. , Khatsko E. N. , Kalinin P. S. , Rykova A. I. , Gurevich A. M. , Glagolev S. A. , Khlybov E. P. , Kostyleva I. E. , Lachenkov S. A.
Published: March 2012

The Volleben effect (“paramagnetic” Meissner effect) was revealed for the first time while measuring the temperature dependence of magnetic moments of Dy1–xYxRh4B4 (x = 0.2, 0.3, 0.4, 0.6) in magnetic fields 1–20 Oe. The effect decreases with increasing magnetic field strength, and at fields below 1 Oe a diamagnetic signal appears. The ferromagnetism of Dy atoms supposedly plays an essential role in the appearance of paramagnetic signal at temperatures below the superconducting transition temperature.
Bias-enhanced nucleation and growth processes for improving the electron field emission properties of diamond films
Authors: Teng Kuang-Yau , Chen Huang-Chin , Tzeng Gaung-Chin , Tang Chen-Yau , Cheng Hsiu-Fung , Lin I-Nan
Published: March 2012

The evolution of diamond films in bias-enhanced-nucleation (BEN) and bias-enhanced-growth (BEG) processes was systematically investigated. While the BEN process can efficiently form diamond nuclei on the Si substrates, BEG with large enough applied field (> –400 V) and for sufficiently long periods (>60 min) was needed to develop proper granular structure for the diamond films so as to enhance the electron field emission (EFE) properties of the films. For the films BEG under −400 V for 60 min (after BEN for 10 min), the EFE process can be turned on at a field as small as 3.6 V/μm, attaining a EFE current density as large as 325 μA/cm2 at an applied field of 15 V/μm. Such an EFE behavior is even better than that of the ultrananocrystalline diamond films grown in CH4/Ar plasma. Transmission electron microscopic examination reveals that the prime factor enhancing the EFE properties of these films is the induction of the nano-graphite filaments along the thickness of the films that facilitates the transport of electrons through the films.
Magnetic fluid dynamics in a rotating magnetic field
Authors: Yoshida T. , Enpuku K. , Dieckhoff J. , Schilling M. , Ludwig F.
Published: March 2012

The dynamics of a magnetic fluid in a rotating magnetic field in the presence of thermal noise were studied by performing numerical simulations based on the Fokker-Planck equation. We first clarified the dynamic properties by numerical simulation such as the frequency dependence of the fluid magnetization, the field-dependent relaxation time, and the M-H curve in a rotating magnetic field. Using the simulation results, we modified an existing analytical model and obtained an empirical expression to quantitatively describe the particle dynamics. The simulation results were compared with experimental results in a rotating magnetic field. The frequency dependence of the magnetization of the magnetic fluid was measured over the linear and nonlinear regions. In order to make a quantitative comparison, the hydrodynamic and effective core size distributions were independently estimated from measurements of the ac susceptibility and the M-H curve. The phase lag and amplitude in a rotating magnetic field obtained from our simulation agreed well with the experimental results.
Acoustic spin pumping: Direct generation of spin currents from sound waves in Pt/Y3Fe5O12 hybrid structures
Authors: Uchida K. , Adachi H. , An T. , Nakayama H. , Toda M. , Hillebrands B. , Maekawa S. , Saitoh E.
Published: March 2012

Using a Pt/Y3Fe5O12 (YIG) hybrid structure attached to a piezoelectric actuator, we demonstrate the generation of spin currents from sound waves. This “acoustic spin pumping” (ASP) is caused by the sound wave generated by the piezoelectric actuator, which then modulates the distribution function of magnons in the YIG layer and results in a pure-spin-current injection into the Pt layer across the Pt/YIG interface. In the Pt layer, this injected spin current is converted into an electric voltage due to the inverse spin-Hall effect (ISHE). The ISHE induced by the ASP is detected by measuring a voltage in the Pt layer at the piezoelectric resonance frequency of the actuator coupled with the Pt/YIG system. The frequency-dependent measurements enable us to separate the ASP-induced signals from extrinsic heating effects. Our model calculation based on the linear response theory provides us with a qualitative and quantitative understanding of the ASP in the Pt/YIG system.
Physical limits of pure superparamagnetic Fe3O4 nanoparticles for a local hyperthermia agent in nanomedicine
Authors: Jeun Minhong , Lee Sanghoon , Kyeong Kang Jae , Tomitaka Asahi , Wook Kang Keon , Il Kim Young , Takemura Yasushi , Chung Kyung-Won , Kwak Jiyeon , Bae Seongtae
Published: March 2012

Magnetic and AC magnetically induced heating characteristics of Fe3O4 nanoparticles (IONs) with different mean diameters, d, systematically controlled from 4.2 to 22.5 nm were investigated to explore the physical relationship between magnetic phase and specific loss power (SLP) for hyperthermia agent applications. It was experimentally confirmed that the IONs had three magnetic phases and correspondingly different SLP characteristics depending on the particle sizes. Furthermore, it was demonstrated that pure superparamagnetic phase IONs (d < 9.8 nm) showed insufficient SLPs critically limiting for hyperthermia applications due to smaller AC hysteresis loss power (Néel relaxation loss power) originated from lower out-of-phase magnetic susceptibility.
Site-controlled InP/GaInP quantum dots emitting single photons in the red spectral range
Authors: Baumann Vasilij , Stumpf Florian , Schneider Christian , Kremling Stefan , Worschech Lukas , Forchel Alfred , Höfling Sven , Kamp Martin
Published: March 2012

We report on site-controlled growth of InP/GaInP quantum dots (QDs) on GaAs substrates. The QD nucleation sites are defined by shallow nanoholes etched into a GaInP layer. Optimized growth conditions allow us to realize QD arrays with excellent long range ordering on nanohole periods as large as 1.25 µm. Single QD lines with an average linewidth of 553 µeV and best values below 200 µeV are observed. Photoluminescence spectroscopy reveals excitonic and biexcitonic emission in the wavelength range of about 670 nm (1.85 eV) with an exciton-biexciton splitting of 1.8 meV. Second-order photon-autocorrelation measurements show clear single photon emission with g(2)(0) = 0.13 ± 0.01.
Formation of the yttrium/germanium interface: Fermi-level pinning and intermixing at room temperature
Authors: Liu Z. Q. , Chim W. K. , Chiam S. Y. , Pan J. S. , Ng C. M.
Published: March 2012

Understanding interfacial phenomena is crucial for precise control in the growth of materials for advanced semiconductor devices. A systematic in situ coverage dependent study is conducted to study the Schottky barrier evolution and chemical reactions at the yttrium/germanium interface. Adatom-induced band bending is present in the early growth stages while metal-induced gap states resulted in strong Fermi level pinning at larger yttrium (Y) thicknesses. Furthermore, significant intermixing occurs at 3 Å thickness of Y and saturates at 17 Å of Y. The underlying mechanism behind this self-limiting intermixing is well-described by a combination of chemical bond and metal-induced weakening theories. The implications of our findings on device performance are discussed.
Mass detection by means of the vibrating nanomechanical resonators
Authors: Stachiv I. , Fedorchenko A. I. , Chen Y.-L.
Published: March 2012

We present a theoretical analysis of the vibrating resonator in cantilever and bridge configurations operating as ultrasensitive mass sensors. An exact solution of the problem has been obtained. For the small mass ratio, the asymptotic solutions (which relate the frequency shift, mass ratio, and position of the attached particle) have been derived. It has been shown that the mass and position of the attached particle for the cantilever configuration can be unambiguously resolved by the use of three consecutive resonant frequencies. For the bridge configuration, the particle mass can be deduced by using only two measured resonant frequencies.
Band-filling dependence of thermoelectric properties in B20-type CoGe
Authors: Kanazawa N. , Onose Y. , Shiomi Y. , Ishiwata S. , Tokura Y.
Published: March 2012

We have synthesized B20-type Co1−xFexGe and Co1−yNiyGe by a high-pressure method and investigated the band-filling dependence of thermoelectric properties. CoGe shows a large figure of merit (ZT≈0.11) due to its low resistivity and large negative Seebeck coefficient (S) (-82μV/K) at 300 K. The sign-crossover of S is observed with increasing Fe concentration. The Boltzmann transport model can explain semi-quantitatively the experimental results, from which we conclude that the large positive or negative S originates from the asymmetric band structure composed of the Dirac cone and the flat band with sharp bends around the Fermi energy.
Correlated conductivity and work function changes in epitaxial graphene
Authors: Nomani Md. W. K. , Shields V. , Tompa G. , Sbrockey N. , Spencer M. G. , Webb R. A. , Koley G.
Published: March 2012

Correlation between conductance and surface work function (SWF) changes caused by molecular adsorption on epitaxial graphene on both faces of 6 H-SiC has been investigated. The SWF and conductance changes, explained on the basis of graphene band diagram, indicate C-face multilayer and Si-face few layer graphene behave as p and n-type sensing layers, respectively. A quantitative model correlating conductance and SWF changes has been proposed within the framework of Boltzmann transport theory. Our results further indicate that for epitaxial graphene, the charge interaction by the adsorbed molecules and related work function changes can be strongly influenced by the SiC substrate.
Photoresponse in epitaxial graphene with asymmetric metal contacts
Authors: Sevak Singh Ram , Nalla Venkatram , Chen Wei , Ji Wei , Wee Andrew T. S.
Published: March 2012

We report photoresponse observations in epitaxial graphene (EG) devices with asymmetric metals (Au, Al) contacted in planar Au/EG/Al device format. The transient photocurrent measurements on the zero-bias device show photocurrent maxima at the Au/EG contact and minima at the EG/Al contact. This observed significant difference between the two types of junctions is responsible for the overall efficient device photoresponse. We have also found that the number of EG layers influences the photocurrent magnitude and response time regardless of incident photon energy or intensity. An external photoresponsivity (or efficiency) of ∼31.3 mA W−1 is achieved with a biased Au/EG/Al photodetector at excitation wavelength of 632.8 nm.
When Soft Spaces Harden: The EU Strategy for the Baltic Sea Region
Authors: Metzger Jonathan , Schmitt Peter
Published: March 2012

This paper investigates the first ever so-called ‘macroregional strategy’ developed under the aegis of the European Commission: the European Union Strategy for the Baltic Sea Region (EUSBSR). Through a drawing together of elements of actor-network theory and regionalization theory, it is argued that the adoption of the EUSBSR can be seen as a milestone within a wider process towards Baltic Sea regionalization, whereby the Baltic Sea region is increasingly ‘solidified’ through the positioning of the European Commission as a spokesperson for the interests of the region. It is further suggested that, if not seriously contested, the possible acceptance of the European Commission as a designated regional spokesperson might be a crucial step in a process whereby the soft space of the Baltic Sea Region may gradually become more formalized. Nonetheless, caution must be taken so as not to confuse degrees of formal institutional fixity with degrees of durability.
Activity Spaces and the Measurement of Clustering and Exposure: A Case Study of Linguistic Groups in Montreal
Authors: Farber Steven , Páez Antonio , Morency Catherine
Published: March 2012

Population segregation measurement is a topic of broad interest in the social sciences. In this paper we draw from recent advances in the spatial analysis literature to derive individualized measures of clustering and exposure. Recent research on accessibility has seen a shift from place-based measures to person-based ones. Similarly, the notion of residential clustering and exposure patterns, while typically related to the distribution of population in zonal systems, can be modified to account for heterogeneous experiences of urban space. In particular, at the individual level, the degree of clustering and exposure is related to personal mobility and the individual experience of space. In this paper we turn to the question of whether individuals belonging to different groups and living in different areas of a city observe differences in their clustering and exposure to population groups over space. The proposed procedure is applied empirically to the case of Montreal to explore how native English speakers of various levels of mobility experience exposure.
Tales from the Road: Reflections on Power and Disciplining within the Academy
Authors: Hammett Daniel
Published: March 2012

The postdoctoral fellowship has become an increasingly integral part of the young academic's career development and is commonly recognised as beneficial to universities' research cultures and publication profiles. However, there has been relatively little critical reflection on the postdoctoral experience. Through a self-reflexive autobiographical account of postdoctoral positionality I explore negotiations of the disciplining practices of the academy. In so doing, I consider competing understandings of the role(s) of postdoctoral fellows, the negotiations of differing academic cultures, and the ways in which forces of reproduction and initiation into the academy perpetuate the transgressive position of the postdoctoral fellow. The argument is made that postdoctoral fellows, particularly international fellows, are continually reinscribed as, simultaneously, an insider and outsider in the academic system, located in a double bind of absence which also offers a privileged moment through which to engage with and work across assumed divisions in the spaces and practices of knowledge production.
Structure of a type III secretion needle at 7-Å resolution provides insights into its assembly and signaling mechanisms
Authors: Fujii Takashi , Cheung Martin , Blanco Amandine , Kato Takayuki , Blocker Ariel J. , Namba Keiichi
Published: March 2012

Type III secretion systems of Gram-negative bacteria form injection devices that deliver effector proteins into eukaryotic cells during infection. They span both bacterial membranes and the extracellular space to connect with the host cell plasma membrane. Their extracellular portion is a needle-like, hollow tube that serves as a secretion conduit for effector proteins. The needle of
Shigella flexneri
is approximately 50-nm long and 7-nm thick and is made by the helical assembly of one protein, MxiH. We provide a 7-Å resolution 3D image reconstruction of the
Shigella
needle by electron cryomicroscopy, which resolves α-helices and a β-hairpin that has never been observed in the crystal and solution structures of needle proteins, including MxiH. An atomic model of the needle based on the 3D-density map, in comparison with that of the bacterial-flagellar filament, provides insights into how such a thin tubular structure is stably assembled by intricate intermolecular interactions. The map also illuminates how the needle-length control protein functions as a ruler within the central channel during export of MxiH for assembly at the distal end of the needle, and how the secretion-activation signal may be transduced through a conformational change of the needle upon host-cell contact.
Magnaporthe oryzae
, the blast pathogen: current status and options for its control.
Authors: Maciel J. L. N.
Published: March 2012

Blast disease is one of the major constraints for food production in the world, affecting many crops of agricultural importance. Wheat blast, since it was first report in the mid-1980s, has been responsible for considerable damage on the wheat fields in several South American countries such as Brazil, Bolivia and Paraguay. Rice blast disease has often been considered as a model for studies on plant-pathogen interactions. Loss of the avirulence gene
AVR-CO39
and mutations on the AVR-Pita are significant examples associated with this interaction. The first example is related to the adaptation of
Magnaporthe oryzae
to the rice crop and the second to the breakdown in cultivar resistance. A large number of genes (about 80 so far) with complete resistance to rice blast have been described, and 13 of them have been cloned. These results, involving avirulence and resistance genes, are important for understanding the biological mechanisms of interaction between pathogen and host, in considering finding strategies to control the disease. There is great concern about the potential spread of the wheat blast pathogen to locations where this disease does not currently occur. There are some wheat-producing regions in the world where wheat blast has not been reported so far, but which have climatic conditions very similar to the regions in South America where wheat blast attacks quite frequently. This situation, in a scenario of climate change, is concerning and demands research action.
The potential of geostatistics and geographic information systems in pest eradication.
Authors: Alves M. de C. , Pozza E. A. , Silva F. M. da , Carvalho L. G. de , Sanches L. , Oliveira M. S. de
Published: March 2012

Complex environmental and agricultural problems require geomatics solutions and soft computing applications that combine knowledge, techniques and methodologies from different sources, for decision-support improvement. It has been even more necessary to use those methodologies in order to optimize resources for environmental impact assessments and to reduce costs in quality control programmes. Thus, this work aims to provide topics about recent developments and initiatives related to environmental and agricultural solutions supported by geographic information systems (GIS) and geostatistics methods. A spatial analysis approach enabled the detection of spatial variation in infestations of pest organisms in the field, indicating the possibility of developing strategies to provide more effective control, less environmental impact and sustainability of the agro-ecosystem, consistent with the philosophy of integrated pest management and precision agriculture.
Consequences of Stocking Headwater Impoundments on Native Populations of Brook Trout in Tributaries
Authors: Humston Robert , Bezold Kelly A. , Adkins Nathaniel D. , Elsey Ryan J. , Huss Jessica , Meekins Brent A. , Cabe Paul R. , King Timothy L.
Published: March 2012

Understanding the impact of hatchery supplementation on the genetics of wild fish populations is important for designing and evaluating ecologically sound stocking practices. For species such as brook trout Salvelinus fontinalis, which are a high priority for conservation and restoration in their native range, understanding the potential impacts of stocking on the functional diversity of wild populations is critical. We sought to determine whether brook trout stocked in low-order reservoirs colonize impoundment feeder streams and if they naturally reproduce and interbreed with established native populations in these tributaries. Analysis of microsatellite DNA allowed us to distinguish hatchery-origin brook trout and putative native strains among tributaries of three stocked reservoirs and one unstocked stream. Hatchery-origin fish were found in tributaries of all stocked reservoirs, mixed with native populations; none were found in an unstocked reference stream that supported wild brook trout. Age-1 brook trout genetically matching a known hatchery strain were found in tributaries of stocked reservoirs, although none of this age were stocked, suggesting that stocked trout have successfully reproduced in these streams. Assignment tests indicated that 4 of the 98 brook trout collected from mixed stocked–native streams were probably hybrids (∼4.1%; 95% confidence interval = 1.3–10.0%). These results suggest that to date the direct impacts of stocking on the genetics of these native populations have been limited but that indirect impacts through competition or similar interactions may still be occurring.

Received January 24, 2011; accepted October 13, 2011
High technology start-up innovation and the role of guanxi: an explorative study in China from an institutional perspective
Authors: Liu Yipeng , Woywode Michael , Xing Yijun
Published: March 2012

This study explores the influences of institutions on high technology start-up innovation in China by taking into account both formal and informal institutions. Our research settings are two high technology parks in Wuxi and Shanghai, respectively. Drawing upon the theoretical lenses of North’s institutional framework and the guanxi literature, we propose an integrative framework to help understand the factors influencing high technology start-up innovation in China. By contrasting different formal institutional settings in Wuxi and Shanghai (in particular, local government interventions), our study shows the positive effect played by local government on innovation and the overarching influence of guanxi. Based on a qualitative research method, nine in-depth semi-structured interviews with the CEOs of high technology start-ups were conducted between August 2009 and September 2010. Additional interviews with government officials and managers of government-owned venture capital funds were performed. We offer evidence to support the dual influence of formal and informal institutions (guanxi). International guanxi triggers government intervention, which in turn facilitates the acquisition of local guanxi. As a multidimensional construct, guanxi has a positive influence on high technology start-up innovation. We contribute to the understanding of the effect of institutions on high technology start-up innovation by disentangling formal and informal institutions. Furthermore, government intervention may have a positive impact on high technology start-up innovation in China, which might shed some light on development in other emerging economies.
Theoretical and experimental study of particle trajectories for nonlinear water waves propagating on a sloping bottom
Authors: Chen Yang-Yih , Li Meng-Syue , Hsu Hung-Chu , Ng Chiu-On
Published: March 2012

A third-order asymptotic solution in Lagrangian description for nonlinear water waves propagating over a sloping beach is derived. The particle trajectories are obtained as a function of the nonlinear ordering parameter
ε
and the bottom slope
α
to the third order of perturbation. A new relationship between the wave velocity and the motions of particles at the free surface profile in the waves propagating on the sloping bottom is also determined directly in the complete Lagrangian framework. This solution enables the description of wave shoaling in the direction of wave propagation from deep to shallow water, as well as the successive deformation of wave profiles and water particle trajectories prior to breaking. A series of experiments are conducted to investigate the particle trajectories of nonlinear water waves propagating over a sloping bottom. It is shown that the present third-order asymptotic solution agrees very well with the experiments.
Equivalence of weak formulations of the steady water waves equations
Authors: Varvaruca Eugen , Zarnescu Arghir
Published: March 2012

We prove the equivalence of three weak formulations of the steady water waves equations, namely: the velocity formulation, the stream function formulation and the Dubreil-Jacotin formulation, under weak Hölder regularity assumptions on their solutions.