bluuebunny/crossref_metadata_2025 huggingface dataset:
Cryptic extinction of a common Pacific lizardEmoia impar(Squamata, Scincidae) from the Hawaiian Islands
Authors: Fisher Robert , Ineich Ivan
Published: March 2012

Most documented declines of tropical reptiles are of dramatic or enigmatic species. Declines of widespread species tend to be cryptic. The early (1900s) decline and extinction of the common Pacific skinkEmoia imparfrom the Hawaiian Islands is documented here through an assessment of literature, museum vouchers and recent fieldwork. This decline appears contemporaneous with the documented declines of invertebrates and birds across the Hawaiian Islands. A review of the plausible causal factors indicates that the spread of the introduced big-headed antPheidole megacephalais the most likely factor in this lizard decline. The introduction and spread of a similar skinkLampropholis delicataacross the islands appears to temporally follow the decline ofE. impar, although there is no evidence of competition between these species. It appears thatL. delicatais spreading to occupy the niche vacated by the extirpatedE. impar. Further confusion exists because the skinkE. cyanura, which is very similar in appearance toE. impar, appears to have been introduced to one site within a hotel on Kaua'i and persisted as a population at that site for approximately 2 decades (1970s–1990s) but is now also extirpated. This study highlights the cryptic nature of this early species extinction as evidence that current biogeographical patterns of non-charismatic or enigmatic reptiles across the Pacific may be the historical result of early widespread invasion by ants. Conservation and restoration activities for reptiles in the tropical Pacific should consider this possibility and evaluate all evidence prior to any implementation.
Programmed cell death in Giardia
Authors: BAGCHI SUSMITA , ONIKU ABRAHAM E. , TOPPING KATE , MAMHOUD ZAHRA N. , PAGET TIMOTHY A.
Published: March 2012

Programmed cell death (PCD) has been observed in many unicellular eukaryotes; however, in very few cases have the pathways been described. Recently the early divergent amitochondrial eukaryote Giardia has been included in this group. In this paper we investigate the processes of PCD in Giardia. We performed a bioinformatics survey of Giardia genomes to identify genes associated with PCD alongside traditional methods for studying apoptosis and autophagy. Analysis of Giardia genomes failed to highlight any genes involved in apoptotic-like PCD; however, we were able to induce apoptotic-like morphological changes in response to oxidative stress (H2O2) and drugs (metronidazole). In addition we did not detect caspase activity in induced cells. Interestingly, we did observe changes resembling autophagy when cells were starved (staining with MDC) and genome analysis revealed some key genes associated with autophagy such as TOR, ATG1 and ATG 16. In organisms such as Trichomonas vaginalis, Entamoeba histolytica and Blastocystis similar observations have been made but no genes have been identified. We propose that Giardia possess a pathway of autophagy and a form of apoptosis very different from the classical known mechanism; this may represent an early form of programmed cell death.
Cardiovascular morbidity, mortality and pharmacotherapy in patients with schizophrenia
Authors: Lahti M. , Tiihonen J. , Wildgust H. , Beary M. , Hodgson R. , Kajantie E. , Osmond C. , Räikkönen K. , Eriksson J.
Published: March 2012

Background

Patients with schizophrenia have excess cardiovascular morbidity and mortality. Previous studies suggest that this may be partly due to inadequate somatic treatment and care, such as non-optimal use of lipid-lowering and antihypertensive pharmacotherapy, but longitudinal studies on such aetiological pathways are scarce.

Method

We investigated the use of lipid-lowering and antihypertensive pharmacotherapy, and the risk of hospitalization for and death from coronary heart disease and stroke among patients with schizophrenia in a birth cohort of 12 939 subjects (Helsinki Birth Cohort Study). This cohort was followed for over 30 adult years by using national databases on cardio- and cerebrovascular hospitalizations and mortality and on reimbursement entitlements and use of drugs for treatment of hypertension, dyslipidaemia, coronary heart disease and diabetes.

Results

Individuals with schizophrenia had a higher risk of hospitalization for coronary heart disease [hazard ratio (HR) 1.65, 95% confidence interval (CI) 1.03–2.57], and mortality from this disease was markedly higher (HR 2.92, 95% CI 1.70–5.00), particularly among women (p=0.001 for women, p=0.008 for men). Women with schizophrenia had also marginally increased stroke mortality (p=0.06). However, patients with schizophrenia used less lipid-lowering (odds ratio 0.47, 95% CI 0.27–0.80) and antihypertensive drug treatment (HR 0.37, 95% CI 0.22–0.61).

Conclusions

In this longitudinal study, coronary heart disease morbidity was increased and coronary heart disease mortality markedly increased in patients, especially in women with schizophrenia. These patients nevertheless received less antihypertensive and lipid-lowering treatment.
Vessel Collision Frequency Estimation in the Singapore Strait
Authors: Weng Jinxian , Meng Qiang , Qu Xiaobo
Published: March 2012

This paper aims to estimate Vessel Collision Frequency in the Singapore Strait. This frequency is obtained as the product of the number of Vessel Conflicts and the causation probability using the real-time vessel movement data from the Lloyd's Marine Intelligence Unit (Lloyd's MIU) database. The results show that the container carriers have the highest Vessel Collision Frequency while Roll-On Roll-Off (RORO) and passenger ships have the lowest frequency. Tankers cause the highest head-on collision frequency. In the Singapore Strait, the most risky overtaking area is between longitudes 103°48′E and 104°12′E. The most risky head-on area is between longitudes 103°50′E and 104°00′E while the majority of crossing collisions occur between longitudes 103°50′E and 104°12′E. The Vessel Collision Frequency is found to be 1·75 per year in the traffic lanes. Currently, westbound traffic in the Strait is more risky than eastbound traffic (the number of westbound collisions in July was 0·0991 while the number of eastbound collisions was 0·0470). Furthermore, the estimated Vessel Collision Frequency during the day is less than that at night. The results of this paper could be beneficial for the Maritime and Port Authority of Singapore to further enhance the navigational safety strategies implemented in the Singapore Strait.
Collision Avoidance at Sea in the Mid-20th Century
Authors: Kemp John , Bechley Mike , Cockcroft Norman , Jurdzinski Mirosław , Thirslund Søren
Published: March 2012

In the middle years of the 20th Century, few merchant ships were fitted with radar and, on those that were, shipmasters often looked upon it as a distraction from a watchkeeper's proper duties rather than as a useful aid to navigation.

For shipmasters of that persuasion, the only place to keep watch was outside the wheelhouse on an exposed bridge wing; mostly the starboard wing because the COLREGS (‘Collision Regulations’ or, more properly, ‘The International Regulations for Preventing Collisions at Sea’) required us to give way to ships approaching from the starboard side. Well, the bridge wing was an attractive place to spend a few hours on a calm, tropical night, but it could be highly disagreeable and sometimes, I thought, actually dangerous, in a North Atlantic rainstorm.
An Autopilot Based on a Local Control Network Design for an Unmanned Surface Vehicle
Authors: Sharma SK , Naeem W , Sutton R
Published: March 2012

Over recent years, a number of marine autopilots designed using linear techniques have underperformed owing to their inability to cope with nonlinear vessel dynamics. To this end, a new design framework for the development of nonlinear autopilots is proposed. Local Control Networks (LCNs) can be used in the design of nonlinear control systems. In this paper, a LCN approach is taken in the design of a nonlinear autopilot for controlling the nonlinear yaw dynamics of an unmanned surface vehicle known as Springer. It is considered the approach is the first of its kind to be used in marine control systems design. Simulation results are presented and the performance of the nonlinear autopilot is compared with that of an existing Springer Linear Quadratic Gaussian (LQG) autopilot using standard system performance criteria. From the results it can be concluded the LCN autopilot out-performed that based on LQG techniques in terms of the selected criteria. Also it provided more energy saving control strategies and would thereby increase operational duration times for the vehicle during real-time missions.
Measurable Events Indexed by Trees
Authors: DODOS PANDELIS , KANELLOPOULOS VASSILIS , TYROS KONSTANTINOS
Published: March 2012

A tree T is said to be homogeneous if it is uniquely rooted and there exists an integer b ≥ 2, called the branching number of T, such that every t ∈ T has exactly b immediate successors. We study the behaviour of measurable events in probability spaces indexed by homogeneous trees.

Precisely, we show that for every integer b ≥ 2 and every integer n ≥ 1 there exists an integer q(b,n) with the following property. If T is a homogeneous tree with branching number b and {At:t ∈ T} is a family of measurable events in a probability space (Ω,Σ,μ) satisfying μ(At)≥ϵ>0 for every t ∈ T, then for every 0<θ<ϵ there exists a strong subtree S of T of infinite height, such that for every finite subset F of S of cardinality n ≥ 1 we have

In fact, we can take q(b,n)= ((2b−1)2n−1−1)·(2b−2)−1. A finite version of this result is also obtained.
Complicated Grief and Suicidality: The Impact of Subthreshold Mood Symptoms
Authors: Dell'Osso Liliana , Carmassi Claudia , Rucci Paola , Ciapparelli Antonio , Conversano Ciro , Marazziti Donatella
Published: March 2012

Introduction

The aim of the present study was to explore the relationship between subthreshold mood symptoms and suicidality in patients with complicated grief (CG).

Methods

Fifty patients with CG were included in the study and evaluated by the Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition Axis-I disorders, the Inventory of Complicated Grief, and the Mood Spectrum Self Report (MOODS-SR) lifetime version, to evaluate the subthreshold mood symptoms.

Results

Twenty-eight patients (56%) reported lifetime suicidal ideation and 11 patients (22%) reported suicide attempts. Subthreshold depressive and rhythmicity/vegetative functions items of the MOODS-SR were significantly associated with increased suicidal ideation and attempts, while subthreshold manic items were associated with suicidal ideation only. Relationships were confirmed after controlling for Axis-I disorders comorbidity.

Conclusion

The results of the present study suggest the usefulness of exploring lifetime subthreshold mood symptoms in CG patients, in order to promptly identify those who may be more prone to suicidality.
Induction of the plasticity-associated immediate early gene Arc by stress and hallucinogens: role of brain-derived neurotrophic factor
Authors: Benekareddy Madhurima , Nair Amrita R. , Dias Brian G. , Suri Deepika , Autry Anita E. , Monteggia Lisa M. , Vaidya Vidita A.
Published: March 2012

Exposure to stress and hallucinogens in adulthood evokes persistent alterations in neurocircuitry and emotional behaviour. The structural and functional changes induced by stress and hallucinogen exposure are thought to involve transcriptional alterations in specific effector immediate early genes. The immediate early gene, activity regulated cytoskeletal-associated protein (Arc), is important for both activity and experience dependent plasticity. We sought to examine whether trophic factor signalling through brain-derived neurotrophic factor (BDNF) contributes to the neocortical regulation of Arc mRNA in response to distinct stimuli such as immobilization stress and the hallucinogen 2,5-dimethoxy-4-iodoamphetamine (DOI). Acute exposure to either immobilization stress or DOI induced Arc mRNA levels within the neocortex. BDNF infusion into the neocortex led to a robust up-regulation of local Arc transcript expression. Further, baseline Arc mRNA expression in the neocortex was significantly decreased in inducible BDNF knockout mice with an adult-onset, forebrain specific BDNF loss. The induction of Arc mRNA levels in response to both acute immobilization stress or a single administration of DOI was significantly attenuated in the inducible BDNF knockout mice. Taken together, our results implicate trophic factor signalling through BDNF in the regulation of cortical Arc mRNA expression, both under baseline conditions and following stress and hallucinogen exposure. These findings suggest the possibility that the regulation of Arc expression via BDNF provides a molecular substrate for the structural and synaptic plasticity observed following stimuli such as stress and hallucinogens.
Geomorphic and exhumational response of the Central American Volcanic Arc to Cocos Ridge subduction
Authors: Morell Kristin D. , Kirby Eric , Fisher Donald M. , van Soest Matthijs
Published: March 2012

The timing of collision of the Cocos Ridge at the Middle America Trench remains one of the outstanding questions in the tectonic evolution of the Central American convergent margin. New analyses of the tectonic geomorphology of the Cordillera de Talamanca, the extinct volcanic arc inboard of the Cocos Ridge, coupled with low temperature thermochronometry data, provide insight into the cooling and erosional history of the arc from late Miocene to present. We identify a low‐relief surface at high elevation along the northeastern flanks of the range, which represents a relict erosional landscape cut across shallow plutonic rocks of the arc edifice. Longitudinal profiles of rivers on this surface are isolated from steep downstream sections by prominent knickzones that are interpreted to reflect a migrating wave of transient incision generated during differential rock uplift of the range. Reconstruction of pre‐incision profiles suggests that rock uplift during the growth of the Cordillera de Talamanca is no greater than ∼2 km. This inference is corroborated by results from our apatite (U‐Th)/He and apatite fission track analyses along an elevation transect on Mt. Chirripó, the highest mountain in the Cordillera de Talamanca. Low‐temperature cooling ages overlap significantly with published high‐temperature40Ar/39Ar ages; the combined results imply that rapid cooling in the late Miocene was related to secular cooling of a shallow pluton, rather than exhumation. Our results imply that rapid incision along downstream channel segments, differential rock uplift, and growth of the Talamanca as a bivergent orogenic wedge associated with the onset of Cocos Ridge subduction are relatively young characteristics of the range. A review of previously published radiometric ages and revised plate reconstructions for the late Miocene further suggest that the cessation of arc volcanism in both the Cordillera de Talamanca and the Cordillera Central of western Panama was coeval with the initiation of oblique subduction of the Nazca plate during the late Miocene. Thus, we conclude that the cessation of arc volcanism in the late Miocene (>5–8 Ma) and the onset of Cocos Ridge collision (<3 Ma) are separate events that reflect recent changes in the configuration of the plate boundary system.
An aerodynamic roughness length map derived from extended Martian rock abundance data
Authors: Hébrard E. , Listowski C. , Coll P. , Marticorena B. , Bergametti G. , Määttänen A. , Montmessin F. , Forget F.
Published: March 2012

Many boundary layer processes simulated within a Mars General Circulation Model (MGCM), including the description of the processes controlling dust rising from the Martian surface, are highly sensitive to the aerodynamic roughness length z0. On the basis of rock‐size frequency distributions inferred from different Martian landing sites and Earth analog sites, we have first established that lognormal‐modeled rock‐size frequency distributions are able to reproduce correctly the observed Martian rock populations. We have validated the hypothesis that the rock abundance ζ of a given area could be estimated at a first order from its thermophysical properties, namely its thermal inertia I and its albedo α. We have demonstrated the possibility of using rock abundance ζ to estimate the roughness density λ on Mars and to retrieve subsequently the aerodynamic roughness length by using semi‐empirical relationships based on terrestrial wind‐tunnel and field measurements. By combining our methodology with remote sensing measurements of the Thermal Emission Spectrometer aboard Mars Global Surveyor, we have derived a global map of the aeolian aerodynamic roughness length with a 1/8° × 1/8° resolution over the entire Martian surface. Contrary to what is often assumed, the Martian aeolian aerodynamic roughness length is spatially highly heterogeneous. At the fullest resolution, the Martian aerodynamic roughness length varies from 10−3 cm to 2.33 cm. About 84% of the Martian surface seems to be characterized by an aeolian aerodynamic roughness length value lower than 1 cm, the spatially uniform value that most of the MGCMs simulations have assumed recently. Since the aerodynamic roughness length z0 is a key parameter in deriving the erosion threshold wind velocities, we anticipate a significant impact of our findings on the efficiencies for lifting dust in future MGCMs.
Changing polar environments: Interdisciplinary challenges
Authors: Shepson Paul B. , Ariya Parisa A. , Deal Clara J. , Donaldson D. James , Douglas Thomas A. , Loose Brice , Maksym Ted , Matrai Patricia A. , Russell Lynn M. , Saenz Benjamin , Stefels Jacqueline , Steiner Nadja
Published: March 2012

In the past few decades, there has been enormous growth in scientific studies of physical, chemical, and biological interactions among reservoirs in polar regions. This has come, in part, as a result of a few significant discoveries: There is dramatic halogen chemistry that occurs on and above the sea ice in the springtime that destroys lower tropospheric ozone and mercury [Simpson et al., 2007; Steffen et al., 2008], the sunlit snowpack is very photochemically active [Grannas et al., 2007], biology as a source of organic compounds plays a pivotal role in these processes, and these processes are occurring in the context of rapidly changing polar regions under climate feedbacks that are as of yet not fully understood [Serreze and Barry, 2011]. Stimulated by the opportunities of the International Polar Year (IPY, 2007–2009), a number of large‐scale field studies in both polar environments have been undertaken, aimed at the study of the complex biotic and abiotic processes occurring in all phases (see Figure 1). Sea ice plays a critical role in polar environments: It is a highly reflective surface that interacts with radiation; it provides a habitat for mammals and micro‐organisms alike, thus playing a key role in polar trophic processes and elemental cycles; and it creates a saline environment for chemical processes that facilitate release of halogenated gases that contribute to the atmosphere's ability to photochemically cleanse itself in an otherwise low‐radiation environment. Ocean‐air and sea ice–air interfaces also produce aerosol particles that provide cloud condensation nuclei.
Outlining a strategic vision for terrestrial geodetic imaging
Authors: Phillips David A. , Oldow John S. , Walker J. Douglas
Published: March 2012

Charting the Future of Terrestrial Laser Scanning in the Earth Sciences and Related Fields; Boulder, Colorado, 17–19 October 2011 A workshop hosted by UNAVCO and funded by the U.S. National Science Foundation (NSF) brought together 80 participants representing a spectrum of research fields with the objective of outlining a strategic vision for the future of terrestrial geodetic imaging as applied to a broad range of research activities at all levels of the community. Earth science investigations increasingly require accurate representation of the Earth surface using three‐dimensional data capture, display, and analysis at a centimeter scale to quantitatively characterize and model complex processes. Recognizing this community need, researchers at several universities and UNAVCO established the NSF‐funded Interdisciplinary Alliance for Digital Field Data Acquisition and Exploration (INTERFACE) project to support a terrestrial laser scanning (TLS) instrument pool and data collection expertise now based at UNAVCO
Much of water used for irrigation comes from nonsustainable sources
Authors: Balcerak Ernie
Published: March 2012

Some of the water used for irrigation comes from renewable sources such as local precipitation, rivers, lakes, and renewable groundwater. But some comes from nonrenewable groundwater sources. Because water supply for irrigation is so essential to the world's food supply, it is important to quantify how much water comes from sustainable sources. Wada et al. conducted a global assessment of how much water used for irrigation comes from nonsustainable groundwater sources. The researchers used a global hydrological model to simulate the amount of water needed for optimal crop growth and the amount available from renewable sources. They combined this information with country‐level data on groundwater use to estimate the amount of groundwater used for irrigation that comes from nonrenewable sources.
On nitrogen fixation and preferential remineralization of phosphorus
Authors: Monteiro F. M. , Follows M. J.
Published: March 2012

Regional and global nitrogen fixation rates are often estimated from geochemical tracers related to N* (= NO3− − 16PO43−). However the patterns of this tracer reflect the influence of numerous processes including nitrogen fixation, denitrification, remineralization of organic matter, variable stoichiometry, atmospheric deposition and physical transport. Here we have used idealized models to illustrate how preferential remineralization of organic phosphorous may explain observed features of N* distribution in the North Atlantic Ocean, including a subsurface maximum and an increased temporal variability in the mid‐thermocline. If preferential remineralization of phosphorus is key in shaping the oceanic distribution of N*, published estimates of nitrogen fixation may be underestimating the marine nitrogen fixation rate by as much as a factor of three.
Diagnosing the influence of diabatic processes on the explosive deepening of extratropical cyclones
Authors: Fink Andreas H. , Pohle Susan , Pinto Joaquim G. , Knippertz Peter
Published: March 2012

A novel version of the classical surface pressure tendency equation (PTE) is applied to ERA‐Interim reanalysis data to quantitatively assess the contribution of diabatic processes to the deepening of extratropical cyclones relative to effects of temperature advection and vertical motions. The five cyclone cases selected, Lothar and Martin in December 1999, Kyrill in January 2007, Klaus in January 2009, and Xynthia in February 2010, all showed explosive deepening and brought considerable damage to parts of Europe. For Xynthia, Klaus and Lothar diabatic processes contribute more to the observed surface pressure fall than horizontal temperature advection during their respective explosive deepening phases, while Kyrill and Martin appear to be more baroclinically driven storms. The powerful new diagnostic tool presented here can easily be applied to large numbers of cyclones and will help to better understand the role of diabatic processes in future changes in extratropical storminess.
Recent geodetic unrest at Santorini Caldera, Greece
Authors: Newman Andrew V. , Stiros Stathis , Feng Lujia , Psimoulis Panos , Moschas Fanis , Saltogianni Vasso , Jiang Yan , Papazachos Costas , Panagiotopoulos Dimitris , Karagianni Eleni , Vamvakaris Domenikos
Published: March 2012

After approximately 60 years of seismic quiescence within Santorini caldera, in January 2011 the volcano reawakened with a significant seismic swarm and rapidly expanding radial deformation. The deformation is imaged by a dense network of 19 survey and 5 continuous GPS stations, showing that as of 21 January 2012, the volcano has extended laterally from a point inside the northern segment of the caldera by about 140 mm and is expanding at 180 mm/yr. A series of spherical source models show the source is not migrating significantly, but remains about 4 km depth and has expanded by 14 million m3since inflation began. A distributed sill model is also tested, which shows a possible N‐S elongation of the volumetric source. While observations of the current deformation sequence are unprecedented at Santorini, it is not certain that an eruption is imminent as other similar calderas have experienced comparable activity without eruption.
High frequency barotropic ocean variability observed by GRACE and satellite altimetry
Authors: Quinn Katherine J. , Ponte Rui M.
Published: March 2012

Previous theoretical and model‐based studies of the relationship between ocean bottom pressure (pb) and sea level (ζ) suggest primarily barotropic variability at mid to high latitudes for scales greater than a few hundred kilometers and periods less than a few months. We use 7‐day GRACE solutions and equivalent satellite altimetry maps, spatially smoothed over 750 km, to investigate the relation between pb and ζ. The observed fields are significantly coherent at high latitudes for periods of ∼14–180 days and mid latitudes for periods of ∼30–100 days. The admittance amplitude between observed pb and ζ is close to 1 for higher frequencies and drops off for lower frequencies. The results provide, for the first time, global observational evidence for the barotropic nature of large‐scale ocean variability at mid and high latitudes. We also demonstrate that GRACE data contain significant information over the oceans at periods <60 days, i.e., shorter than the nominal monthly time resolution.
A suggestion that two‐dimensional turbulence contributes to polar cap convection for Bz north
Authors: Kelley M. C. , Kim H.‐J.
Published: March 2012

Recently, a linear dependence has been found between the polar cap potential and the log of ULF power in the solar wind for Bz north. We argue here that this is very strong evidence that Alfvén waves propagating from the solar wind to the polar cap drive two‐dimensional turbulence in agreement with other work along these lines. In brief, two‐dimensional (2‐D) turbulence is characterized by an inverse cascade of energy from intermediate to large scales, eventually leading to two large counter‐rotating vortices filling the available volume and, we think, creating two of the four vortices in the Bz north polar cap. In this model, the Alfvén waves create velocity shear at the 500 or so kilometer scale associated with polar cap arcs. This energy/vorticity then inverse cascades to fill the polar cap.
Identifying reliable traits across laboratory mouse exploration arenas: A meta-analysis
Authors: Galsworthy Michael , Madani Rime , Lipp Hans-Peter
Published: March 2012

This study is a meta-analysis of 367 mice from a collection of behaviour neuroscience and behaviour genetic studies run in the same lab in Zurich, Switzerland. We employed correlation-based statistics to confirm and quantify consistencies in behaviour across the testing environments. All 367 mice ran exactly the same behavioural arenas: the light/dark box, the null maze, the open field arena, an emergence task and finally an object exploration task. We analysed consistency of three movement types across those arenas (resting, scanning, progressing), and their relative preference for three zones of the arenas (home, transition, exploration). Results were that 5/6 measures showed strong individual-differences consistency across the tests. Mean inter-arena correlations for these five measures ranged from +.12 to +.53. Unrotated principal component factor analysis (UPCFA) and Cronbach’s alpha measures showed these traits to be reliable and substantial (32-63% of variance across the five arenas). UPCFA loadings then indicate which tasks give the best information about these cross-task traits. One measure (that of time spent in “intermediate” zones) was not reliable across arenas. Conclusions centre on the use of individual differences research and behavioural batteries to revise understandings of what measures in one task predict for behaviour in others. Developing better behaviour measures also makes sound scientific and ethical sense.
Nuclear Magnetic Resonance
Authors: Swiezewska Ewa
Published: March 2012

As a spectroscopic method, nuclear magnetic resonance (NMR) has seen spectacular growth, both as a technique and in its applications. Today's applications of NMR span a wide range of scientific disciplines, from physics to biology to medicine. Each volume of Nuclear Magnetic Resonance comprises a combination of annual and biennial reports which together provide comprehensive coverage of the literature on this topic. This Specialist Periodical Report reflects the growing volume of published work involving NMR techniques and applications, in particular NMR of natural macromolecules, which is covered in two reports: NMR of Proteins and Nucleic Acids and NMR of Carbohydrates, Lipids and Membranes. In his foreword to the first volume, the then editor, Professor Robin Harris announced that the series would be a discussion on the phenomena of NMR and that articles will be critical surveys of the literature. This has certainly remained the case throughout the series, and in line with its predecessors, Volume 40 aims to provide a comprehensive coverage of the relevant NMR literature. For the current volume this relates to publications appearing between June 2009 and May 2010 (the nominal period of coverage in volume 1 was July 1970 to June 1971). Compared to the previous volume there are some new members of the reporting team. Theoretical Aspects of Spin-Spin Couplings are covered by J. Jazwinski, while E. Swiezewska and J.Wojcik provide an account of NMR of Carbohydrates, Lipids and Membranes.
Maxwell's equations and electromagnetic Lagrangian density in fractional form
Authors: Jaradat E. K. , Hijjawi R. S. , Khalifeh J. M.
Published: March 2012

The fractional form of the electromagnetic Lagrangian density is presented using the Riemann-Liouville fractional derivative. Agrawal procedure is employed to obtain Maxwell's equations in fractional form. The Hamilton equations of motion resulting from the electromagnetic Lagrangian density are obtained. Conserved quantities, such as energy density, momentum, and Poynting's vector, are also derived using fractional Noether's theorem.
Anomalous Hall effect in the Co-based Heusler compounds Co2FeSi and Co2FeAI
Authors: Imort I.-M. , Thomas P. , Reiss G. , Thomas A.
Published: March 2012

The anomalous Hall effect (AHE) in the Heusler compounds Co2FeSi and Co2FeAl is studied in dependence of the annealing temperature to achieve a general comprehension of its origin. We have demonstrated that the crystal quality affected by annealing processes is a significant control parameter to tune the electrical resistivity ρxx as well as the anomalous Hall resistivity ρahe. Analyzing the scaling behavior of ρahe in terms of ρxx points to a temperature-dependent skew scattering as the dominant mechanism in both Heusler compounds.
Magnetic properties of Sm5Fe17/Fe composite magnets produced by spark plasma sintering method
Authors: Saito Tetsuji , Miyoshi Hiroya
Published: March 2012

Mixtures of powdered Sm5Fe17 melt-spun ribbon and Fe powder were consolidated into bulk magnets by the spark plasma sintering (SPS) method. Although these bulk magnets consisted of the hard magnetic Sm5Fe17 and soft magnetic α-Fe phases, they had a smooth hysteresis loop and exhibited coercivity. Among the magnets studied, the Sm5Fe17/Fe composite magnet with 30%Fe showed a remanence of 94 emu/g with a coercivity of 2.9 kOe.
Spin-current switch based on vertical asymmetric double quantum dots containing single manganese
Authors: Qu Fanyao , Villegas-Lelovsky L. , Guassi Marcos R. , López-Richard V. , Marques G. E.
Published: March 2012

We propose a spin-current switch, which is composed of vertical asymmetric double quantum dots (DQD) containing single manganese, and subjected to an electric field along the growth direction. We demonstrate electrical tunability of charge and spin dependent interdot quantum couplings between two dots. Manipulation of individual Mn2+ spin and electrical control of spin-splitting depend strongly on the magnetic impurity position. By sweeping electrical field, the spin-splitting is reduced from its maximum value to zero for Mn2+ ion located inside one of the quantum dots. For Mn2+ ion inside the other quantum dot, however, the spin-splitting builds up from zero to its maximum value. Hence the spin-splitting may act as a fingerprint of spin- and charge-state of hole in single-Mn doped DQDs, and may also be used as the basis to construct a spin-current switch.
Structure and magnetic properties of FePt(001) graded films deposited on glass substrates
Authors: Yuan Fu-Te , Lin Yi-Hung , Mei J. K. , Hsu Jen-Hwa , Kuo P. C.
Published: March 2012

This study examines L10 FePt (001) hard magnetic films that were coated with a layer having graded perpendicular magnetic constant (Ku) and with a disordered FePt soft layer on glass substrates. The 5 nm-thick hard layer exhibits a clear (001) texture, large perpendicular magnetic anisotropy (PMA), and an island-like morphology with particle size of 15–25 nm. The deposition of the graded or soft layer with a thickness of 5–15 nm does not change the particle size. The graded and hard/soft samples both exhibit reduced out-of-plane coercivity (Hc⊥) but their reversal behaviors differ. Strong exchange coupling appears between the hard and graded layers, maintaining high PMA. However, hard/soft films exhibit weak coupling such that the film becomes in-plane anisotropic when the thickness of the soft layer exceeds 5 nm. The investigations of magnetic domain structures further reveal different magnetic coupling configurations between different types of films. The results herein are consistent with theoretical predictions and are useful for future graded media design.
Restoration the domain structure from magnetic force microscopy image
Authors: Wu Dongping , Lou Yuanfu , Wei Fulin , Wei Dan
Published: March 2012

This contribution gives an approximation method to calculate the stray field of the scanning plane from the magnetic force microscopy (MFM) force gradient image. Before calculation, a Butterworth low-pass filter has been used to remove a part of the noise of the image. The discrete Fourier transform (DFT) method has been used to calculate the magnetic potential of the film surface. It shows that the potential is not correct because the low-frequency noise has been enlarged. The approximation method gives a better result of the potential and proves that the MFM force gradient of the perpendicular component image also gives the perpendicular component of the stray field. Supposing that the distance between the tip and the sample is as small as near zero, the force gradient image also gives the magnetic charge distribution of the film surface. So if the orientation of the film from hysteresis loop is known, then the domain structure of the film can be determined. For perpendicular orientation, the absolution value of the perpendicular component of stray field gives the domain and domain wall position. For in-plane orientation, the absolution value of in-plane component of stray field gives the domain and domain wall position.
Abnormal magnetic behaviors and large magnetocaloric effect in MnPS3 nanoparticles
Authors: Zeng R. , Wang S. Q. , Du G. D. , Wang J. L. , Debnath J. C. , Shamba P. , Fang Z. Y. , Dou S. X.
Published: March 2012

A nanostructured honeycomb lattice consisting of MnPS3 nanoparticles synthesized via the ion-exchange technique was found to have restacked molecular layers stabilized by H2O insertion between the layers. Susceptibility (χ) and heat capacity measurements showed the absence of long range magnetic ordering, at least down to 2 K. However, the χ data showed that the system possesses a high effective Curie temperature, suggesting that the system is in a high spin lattice disordered state. Evaluation of the magnetocaloric effect indicates that the system has a large reversible magnetic-entropy change (−ΔSm) of 6.8 and 12.8 J/kg K and an adiabatic temperature change (ΔTad) of 3.8 K and 8 K at 2.85 K for magnetic field changes of 3 T and 9 T, respectively.
Neutron scattering measurements in RbMnF3: A test of spin-wave-region theories at low temperatures and critical behavior near TN
Authors: Bykovetz N. , Hoser A. , Klein J. , Lin C. L. , Seehra M. S.
Published: March 2012

With the discovery of magnetic ordering in RbMnF3, this unique antiferromagnetic system was recognized as a prime case for a test of conventional spin-wave theory (CSWT) because of its negligibly small anisotropy and its simple, cubic structure. CSWT predicts a simple T2 power-law fall-off of the sublattice magnetization. Yet to this day, no stringent tests have been made of this prediction. Seiden [(Phys. Lett. 28 A, 239 (1968)] deduced a T3 low-temperature behavior on the basis of antiferromagnetic resonance measurements, concluding that CSWT was not supported. We have recently carried out neutron scattering measurements of both single-crystal and powdered samples of RbMnF3 in order to test for CSWT, Seiden’s result, and two other more recent semiempirical spin-wave schemes, and we present an analysis of the results. Measurements in the critical regime gave values of the critical exponent β and of TN that are in agreement with previous measurements.
Ferromagnetic resonance properties of granular Co-Cr-Pt films measured by micro-fabricated coplanar waveguides
Authors: Kobayashi T. , Ishida N. , Sekiguchi K. , Nozaki Y.
Published: March 2012

Ferromagnetic resonance (FMR) spectroscopy of granular Co-Cr-Pt films has been studied by means of a vector network analyzer. Though the granular Co-Cr-Pt films have weak magnetic susceptibility, the structural optimization of a coplanar waveguide (CPW) enables the measurement of the weak FMR signal of granular Co-Cr-Pt films, which are a promising medium for magnetic recording. The observed FMR spectra are consistent with the Kittel formula. The optimization of the CPW is well established by our simple model, providing a method to explore the basic magnetic properties of a granular medium.
Anomalous magnetic ground state in PrSi evidenced by the magnetocaloric effect
Authors: Snyman J. L. , Strydom A. M.
Published: March 2012

Previous investigations into the physical properties of PrSi have shown this compound to order ferromagnetically at 54 K. However, the magnetic ground state has not yet been determined unambiguously. PrSi crystallizes in the orthorhombic FeB-type structure. Typically, the crystalline electric field (CEF) would uplift the degeneracy of the J=4 Pr3+ free-ion ground state multiplet, yielding nine (normally non-magnetic) singlets. It is known that magnetic order in such systems may be established via the admixture of two singlets into a doublet state, analogous to TmNi, which crystallizes in the same structure. From symmetry considerations, collinear ferromagnetically ordered moments should lie parallel to the crystallographic b-axis. However, neutron diffraction experiments have shown that the easy magnetic axis lies in the ac-plane. This is the first suggestion that the ground state in PrSi is not determined by the CEF alone. Here, we investigate the ground state properties of PrSi by analyzing its specific heat. A Schottky contribution associated with the thermal population of CEF-split energy levels is absent from the 4f-electron contribution to the specific heat and the magnetic configurational entropy points to a full nine-fold degenerate J=4 multiplet magnetic ground state. The strongest evidence for such a ground state is found when the magnetocaloric effect (MCE) in this system is considered. Furthermore, the MCE indicates the presence of a significant higher order exchange term in the magnetic Hamiltonian.
Steel stress monitoring sensor based on elasto-magnetic effect and using magneto-electric laminated composite
Authors: Duan Yuan-Feng , Zhang Ru , Zhao Yang , Wing Or Siu , Fan Ke-Qing , Tang Zhi-Feng
Published: March 2012

Monitoring of stresses in in-service steel structural components is challenging, but crucial to structural safety and health evaluation. Elasto-magnetic (EM) sensors are promising for stress monitoring of steel structural components, because of their great capabilities for actual stress measurement, noncontact monitoring, and long service life. However, the low sensitivity, low signal-to-noise ratio, slow response, and complicated installation of the EM sensors limit their application flexibility. This paper presents a steel stress monitoring sensor (SSMS) using a magneto-electric (ME) sensing unit to overcome the drawbacks intrinsic in the conventional EM sensors. The ME sensing unit is made of a ME-laminated composite of Terfenol-D magnetostrictive alloy and 0.7Pb_Mg1/3Nb2/3_O3−0.3PbTiO3 (PMN-PT) piezoelectric crystal. The theoretical analysis and experimental characterization conducted on the ME sensing unit show high sensitivity, real-time response, and good linearity. Stress monitoring of a steel bar under tension is implemented for the SSMS with a pulse excitation of magnetization. The results demonstrate that the SSMS is feasible for real-time stress monitoring of steel structural components with high sensitivity, fast response, and ease of installation.
Noise correlation in fundamental mode orthogonal fluxgate
Authors: Butta M. , Sasada I.
Published: March 2012

One of the key issues to reduce noise in a flux gate is the knowledge of how the noise is originated within the sensor. In this paper we measured the noise of an orthogonal flux gate operated in the fundamental mode in narrow regions of the magnetic wire used as a core, and we show how the correlation between the noise measured in two different sections drops when the distance between the sections is increased. This indicates that the noise is originated locally in the magnetic wire and then spread thought the wire due to its high permeability. This was confirmed by the measurement with a longer wire that yields higher correlation than those observed with shorter ones. Therefore, uncorrelated noise generated in sections of the wire far enough can be compensated. Finally, we show how the noise from two different wires is totally uncorrelated even if excited by the same current source, confirming that the noise is originated within the magnetic core. Such results can be used to design sensors with lower noise.
Magnetic properties of Dy-diffused Nd-Fe-B powder prepared by crystallization from amorphous state
Authors: Fukunaga Hirotoshi , Yamamoto Ikuo , Nakano Masaki , Yanai Takeshi
Published: March 2012

The method of enhancing coercivity of isotropic Nd-Fe-B flakes using simultaneous diffusion of Dy and crystallization from the amorphous state was also applied to Nd-Fe-B powders, in this study. Metal Dy coating was synthesized on amorphous Nd2.36Fe14B1.05 powders by the vapor deposition method, and the powders were crystallized by a flash annealing. Simultaneous diffusion of Dy from their surfaces using the crystallization enhanced the coercivity of isotropic Nd-Fe-B powders. The coercivity Hc increased and the remanence Mr decreased nearly linearly with the amount of Dy, and the coating of 4.5 wt.% Dy resulted in 25.3% increase in Hc and 6.5% decrease in Mr. The decrease in Mr of the Nd-Fe-B powders is nearly the same in magnitude to that previously reported for Nd2.36Fe14B1.05 flakes, which suggests that the method of Dy diffusion using crystallization from amorphous state is applicable to Nd-Fe-B amorphous powders as well as flakes. The energy-dispersive X-ray spectroscopy revealed that Dy coating is inhomogeneous, and a further enhancement in Hc is expected by improving the coating method.
Interface roughness induced asymmetric magnetic property in sputter-deposited Co/CoO/Co exchange coupled trilayers
Authors: Wang J. , Sannomiya T. , Shi J. , Nakamura Y.
Published: March 2012

The effect of interface roughness on magnetic properties of exchange coupled polycrystalline Co/CoO(tAF)/Co trilayers has been investigated by varying antiferromagnetic layer (CoO) thickness. It has been found that the upper CoO/Co interface becomes rougher with increasing CoO layer thickness, resulting in stronger exchange bias of the upper interface than the lower one. The interfacial exchange coupling is strengthened by the increase of defect-generated uncompensated antiferromagnetic spins; such spins form coupling with spins in the Co layer at the interface. As a result, the CoO layer thickness dependence of exchange bias is much enhanced for the upper Co layer. The transition from anisotropic magnetoresistance to isotropic magnetoresistance for the top Co layer has also been found. This could be attributed to the defects, probably partial thin oxide layers, between Co grains in the top Co layer that leads a switch from spin-orbit scattering related magnetoresistance to spin-dependent electron scattering dominated magnetoresistance.
Exchange stiffness in thin film Co alloys
Authors: Eyrich C. , Huttema W. , Arora M. , Montoya E. , Rashidi F. , Burrowes C. , Kardasz B. , Girt E. , Heinrich B. , Mryasov O. N. , From M. , Karis O.
Published: March 2012

The exchange stiffness (Aex) is one of the key parameters controlling magnetization reversal in magnetic materials. We used a method based on the spin spiral formation in two ferromagnetic films antiferromagnetically coupled across a non-magnetic spacer layer and Brillouin scattering to measure Aex for a series of Co1-δXδ (X = Cr, Ni, Ru, Pd, Pt) thin film alloys. The results show that Aex of Co alloys does not necessarily scale with Ms; Aex approximately decreases at the rate of 1.1%, 1.5%, 2.1%, 3.5%, and 5.6%, while Ms decreases at the rate of 1.1%, 0.5%, 1.1%, 3.7%, and 2.5% per addition of 1 at % of Pt, Ni, Pd, Cr, and Ru, respectively.
Magnetism and structure of anatase (Ti1−xVx)O2 films
Authors: Le Roy D. , Valloppilly S. , Skomski R. , Liou S.-H. , Sellmyer D. J.
Published: March 2012

Anatase TiO2 is known as a promising host material for a wide-gap ferromagnetic semiconductor as it is a good solvent for numerous transition-metal elements. We report on the structural and magnetic properties of epitaxially grown anatase (Ti1−xVx)O2 layers where x covers the whole range of solubility of V atoms in anatase TiO2 and beyond the solubility limit of 21%. We measured an average magnetic moment per vanadium as high as 1 µB with a magnetic percolation threshold of less than 6% which agrees with recent theoretical predictions. Interestingly, our results show a decrease of the average V magnetic moment as x increases throughout the solubility range. Anatase (Ti1−xVx)O2 is no longer present beyond the solubility limit, where the nonmagnetic VO2 phase forms and destroys the net magnetization.