bluuebunny/crossref_metadata_2025 huggingface dataset:
Cardiac magnetic resonance imaging predicts cardiac catheter findings for great artery stenosis in children with congenital cardiac disease
Authors: Oswal Nilesh , Sullivan Ian , Khambadkone Sachin , Taylor Andrew M. , Hughes Marina L.
Published: August 2011

Objective

To assess the cardiac catheterisation findings of all children in whom cardiac magnetic resonance imaging found great artery stenosis.

Methods

We conducted a retrospective analysis of all 45 consecutive children with congenital cardiac disease who were undergoing cardiac catheterisation for intervention on cardiac magnetic resonance-defined great vessel stenosis, between January, 2006 and August, 2008.

Results

Following cardiac magnetic resonance, 60 significant great vessel stenoses were identified and referred to cardiac catheterisation for intervention. All patients were catheterised within a median and interquartile range of 84 and 4–149 days, respectively, of cardiac magnetic resonance. At cardiac catheterisation, the children were aged 11.5 years – with an interquartile range of 3.8–16.9 years – and weighed 34 kilograms – with an interquartile range of 15–56 kilograms. Comparing cardiac magnetic resonance and cardiac catheterisation findings, 53 (88%) findings were concordant and seven were discordant. In six of seven (86%) discordant observations, cardiac magnetic resonance defined moderate–severe great vessel stenosis – involving three branch pulmonary arteries and three aortas. This was not confirmed by cardiac catheterisation, which revealed mild stenoses and haemodynamic gradients insufficient for intervention. In one patient, a mild, proximal right pulmonary artery narrowing was found at cardiac catheterisation, which was not mentioned in the cardiac magnetic resonance report. There was no difference between discordant and concordant groups on the basis of patient age, weight, interval between cardiac magnetic resonance and cardiac catheterisation, or type of lesion.

Conclusion

Invasive assessment confirmed cardiac magnetic resonance-diagnosed great vessel stenosis in the majority of this cohort. The predominant discordant finding was lower catherisation gradient than predicted by morphologic and functional cardiac magnetic resonance assessment. Flow volume diversion – for example, unilateral pulmonary artery stenosis – and anaesthetic effects may account for some differences. Prospective refinement of cardiac magnetic resonance and interventional data may further improve the validity of non-invasive imaging thresholds for intervention.
Individual Therapy Attrition Rates in a Low-Intensity Service: A Comparison of Cognitive Behavioural and Person-Centred Therapies and the Impact of Deprivation
Authors: Grant Karra , McMeekin Elizabeth , Jamieson Ruth , Fairfull Alexandra , Miller Chris , White Jim
Published: August 2011

Background: This paper looks at attrition in relation to deprivation and type of therapy – CBT or person-centred counselling. Method: Case notes of all those referred in a 4-month period (n = 497) were assessed for those who failed to opt-in; those who opted-in but failed to attend first appointment and those who attended first appointment but subsequently dropped-out. Results: Significant numbers failed to opt-in, attend first appointment or dropped out during therapy. There were no differences between CBT and PCT. Those from the most deprived areas were less likely to opt-in. Conclusions: We need to develop better approaches to attracting and maintaining contact with individuals complaining of common mental health problems.
Can ‘boost’ be avoided in pre-invasive and early breast cancer with free surgical margins after breast conservation surgery and irradiation?
Authors: Ampil Federico L. , Chu Quyen , Caldito Gloria , Li Benjamin D.L. , Burton Gary V. , Kim Roger H.
Published: August 2011

Guidelines concerning early stage breast cancer do not clearly recommend tumour bed boost dose after breast conserving surgery and irradiation when the resection margins are negative. Because the number of these patients is expected to increase, we evaluated the results of our treatment scheme in which the additional tumour bed dose was omitted. One hundred consecutive individuals with ductal carcinoma in-situ or stage I or II cancer of the breast were identified for this retrospective analysis. The observed ipsilateral breast tumour recurrence and 10-year disease-free survival rates were 4% and 91% respectively. Univariate analysis indicated that triple receptor negative tumour is the most independent prognostic risk factor. In conclusion, the observed low rate of local recurrence and many long-term survivors in this study seem to legitimize the omission of the tumour bed boost dose after whole breast irradiation in women with early carcinoma of the breast and free breast conserving surgical margins.
Using reference values to assess environmental sustainability of dairy farms
Authors: Acosta-Alba I. , Corson M.S. , van der Werf H.M.G. , Leterme P.
Published: August 2011

One challenge for the environmental assessment of agricultural systems is to progress from estimating whether one farming system has fewer impacts than another to estimating whether or not it can be considered environmentally sustainable. To this end, we developed reference values (RVs) of farm emissions or energy use per hectare that defined hypothetical sustainability thresholds in each of three impact categories: climate change, water-quality degradation and non-renewable energy use. We applied one RV per category to the potential impacts (estimated by life-cycle assessment) of 45 French dairy farms to identify farms below RVs in each impact category and then evaluated their management and production characteristics. Seventeen of the 45 farms lie below at least one of the three RVs. Groups of farms below RVs had a higher percentage of organic farms, larger mean usable agricultural area, longer mean pasture residence time and lower mean inputs of concentrate feed and nitrogen than those above the same RVs. In consequence, the groups below RVs also tended to have lower mean milk production per cow and per hectare. All milk production systems can move toward environmental sustainability even though, according to production mode and intensity, some potential impacts are easier to reduce than others. Most farms were unable to attain the lowest RVs, suggesting that policy-makers may need to consider less ambitious RVs for existing agricultural systems. Otherwise, the distance between normative RVs and indicator values of dairy farms suggest that production and consumption of agricultural products will need to change if sustainability goals do not.
Maternal and paternal psychopathology increases risk of offspring ADHD equally
Authors: Lindblad F. , Weitoft G. Ringbäck , Hjern A.
Published: August 2011

Background.

Parental psychopathology may increase the risk of attention-deficit hyperactivity disorder (ADHD) in the offspring. The aim of this study was to analyze if/how gender influences the association between parental psychiatric/addictive disorders and ADHD medication in the offspring.

Methods.

Register study in national birth cohorts of 1.1 million 6–19-year-olds. In this population, 7960 individuals with ADHD medication were identified in the Swedish Prescribed Drug Register during 2006. Data on parental psychiatric/addictive disorders and suicide death were obtained through linkages to national registers. Logistic regression was used for analyses with multiple adjustments for socio-economic, regional and demographic confounders.

Results.

Parental diagnosis related to illicit drugs was associated with the highest odds ratios (ORs) of ADHD medication (OR: ~3.5–4), followed by suicide attempt/death (OR: ~ 3–3.5), alcohol (OR:~2.5–3), affective disorder (OR: ~ 2.5) and psychosis (OR: ~ 2–2.5). The ORs were of similar magnitudes for maternal and paternal psychopathology and did not vary by the gender of the offspring. Adjusting for social characteristics decreased the ORs substantially and in the same way regarding fathers' and mothers' possible influence on the risk of ADHD in children.

Conclusions.

Neither parental nor offspring gender seems to influence the link between parental addictive/psychiatric disorder and offspring ADHD.
Tide model accuracy in the Amundsen Sea, Antarctica, from radar interferometry observations of ice shelf motion
Authors: McMillan M. , Shepherd A. , Nienow P. , Leeson A.
Published: August 2011

This study assesses the accuracy of tide model predictions in the Amundsen Sea sector of West Antarctica. Tide model accuracy in this region is poorly constrained, yet tide models contribute to simulations of ocean heat transfer and to the removal of tidal signals from satellite observations of ice shelves. We use two satellite‐based interferometric synthetic aperture radar (InSAR) methods to measure the tidal motion of the Dotson Ice Shelf at multiple epochs: a single‐difference technique that measures tidal displacement and a double‐difference technique that measures changes in tidal displacement. We use these observations to evaluate predictions from three tide models (TPXO7.1, CATS2008a_opt, and FES2004). All three models perform comparably well, exhibiting root‐mean‐square deviations from the observations of ∼9 cm (single‐difference technique) and ∼10 cm (double‐difference technique). Care should be taken in generalizing these error statistics because (1) the Dotson Ice Shelf experiences relatively small semidiurnal tides and (2) our observations are not sensitive to all tidal constituents. An error analysis of our InSAR‐based methods indicates measurement errors of 7 and 4 cm for the single‐ and double‐difference techniques, respectively. A model‐based correction for the effect of fluctuations in atmospheric pressure yields an ∼6% improvement in the agreement between tide model predictions and observations. This study suggests that tide model accuracy in the Amundsen Sea is comparable to other Antarctic regions where tide models are better constrained. These methods can be used to evaluate tide models in other remote Antarctic waters.
Astronomical forcing and chronology of the early Toarcian (Early Jurassic) oceanic anoxic event in Yorkshire, UK
Authors: Kemp David B. , Coe Angela L. , Cohen Anthony S. , Weedon Graham P.
Published: August 2011

During the early Toarcian (∼183 Ma ago), a high rate of organic carbon burial globally over a brief interval of time has led to the recognition of a major oceanic anoxic event (OAE). A pronounced negative excursion in the carbon‐isotope composition of marine organic matter, marine carbonate and terrestrial plant material is a key feature of this event but the precise timescale and cause(s) of this isotopic anomaly are debated. Associated with the negative carbon‐isotope excursion is evidence for a coeval rise in seawater palaeotemperature, an increase in continental weathering rates, and the mass extinction of marine invertebrate species. The early Toarcian OAE provides evidence for the Earth's response during rapid climate change, and critical to our understanding of the event is a high‐resolution timescale that allows us to quantify the rates, duration and lead/lag times of environmental processes. In this study, we present 2743 new high‐resolution organic carbon, sulphur and carbonate concentration data from samples of well‐preserved organic‐rich mudrocks spanning the early Toarcian OAE in Yorkshire, UK. We have used these data to document the geochemical changes and significantly extend and refine the astronomical timescale across this event. Our detailed analysis of the relationship between astronomical forcing and carbon isotope changes in both Yorkshire and a section from Peniche, Portugal, indicates that astronomical forcing paced the timing of major shifts in δ13C and hence climate in both sections. Our analyses also demonstrate that there was a marked increase in the relative strength of astronomical forcing recorded at the onset of the OAE, and that the recorded nature of astronomical forcing changed during the event. Both the Yorkshire and Peniche cyclostratigraphies suggest that one astronomical forcing parameter paced environmental change through the δ13C event, and that this parameter was obliquity or precession.
Detecting cycles in stratigraphic data: Spectral analysis in the presence of red noise
Authors: Vaughan S. , Bailey R. J. , Smith D. G.
Published: August 2011

We discuss the detection of cyclic signals in stratigraphic ‘time series’ using spectral methods. The dominant source of variance in the stratigraphic record is red noise, which greatly complicates the process of searching for weak periodic signals. We highlight two issues that are more significant than generally appreciated. The first is the lack of a correction for ‘multiple tests’ – many independent frequencies are examined for periods but using a significance test appropriate for examination of a single frequency. The second problem is the poor choice of null hypothesis used to model the spectrum of non‐periodic variations. Stratigraphers commonly assume the noise is a first‐order autoregressive process – the AR(1) model – which in practice often gives a very poor match to real data; a fact that goes largely unnoticed because model checking is rarely performed. These problems have the effect of raising the number of false positives far above the expected rate, to the extent that the literature on spatial stratigraphic cycles is dominated by false positives. In turn these will distort the construction of astronomically calibrated timescales, lead to inflated estimates of the physical significance of deterministic forcing of the climate and depositional processes in the pre‐Neogene, and may even bias models of solar system dynamics on very long timescales. We make suggestions for controlling the false positive rate, and emphasize the value of Monte Carlo simulations to validate and calibrate analysis methods.
Calibratability and its impact on configuration design for the LOFAR and SKA phased array radio telescopes
Authors: Wijnholds S. J. , Bregman J. D. , van Ardenne A.
Published: August 2011

The Low Frequency Array (LOFAR) is a synthesis radio telescope covering the 10–240 MHz range. LOFAR is the first operational pathfinder to the Square Kilometre Array (SKA), a future radio telescope envisaged to be at least an order of magnitude more sensitive than current instruments. LOFAR exploits the same hierarchical beamforming structure as envisaged for the SKA phased array systems. In this paper, we describe the system requirements imposed by calibratability, i.e., the ability to perform a proper self‐calibration of the instrument, for the low frequency regime. We derive requirements on station size, aperture efficiency and side lobe level. We also discuss the impact of the polarimetric response of the stations. We discuss the LOFAR design choices made to satisfy these requirements and indicate their implications for SKA phased array systems. This demonstrates that calibratability imposes requirements complementary to those based on imaging requirements and that self‐calibratability has a significant impact on configuration design considerations.
Geological slip rates along the North Anatolian Fault in the Marmara region
Authors: Gasperini Luca , Polonia Alina , Çağatay M. Namık , Bortoluzzi Giovanni , Ferrante Valentina
Published: August 2011

Reliable piercing points on both sides of the Sea of Marmara enabled us to obtain an estimate of the slip‐rate over time scales of 10–15 ka on different fault strands of the North Anatolian Fault (NAF) system. We analyzed geomorphic features in the gulfs of Izmit, Gemlik (Sea of Marmara) and Saros (NE Aegean Sea), which were passively displaced by the NAF strands after their abandonment related to the post‐glacial sea level rise. Results for the main northern strand, consistently similar on both sides of the Marmara pull‐apart, are in the order of 10 mm/yr, about one half of that expected from geodetic measurements and accepted plate‐tectonic models. In the southern branch of the NAF, the estimated rate of ∼4 mm/yr is only slightly higher than that given by geodetic models. Our findings have implications for both neo‐tectonic reconstructions of the submerged portion of the NAF system, and fault interactions and seismic hazard estimates in the Marmara region. They suggest that, either the total Anatolia/Eurasia plate motion is more diffuse than previously reported, or geodetic data are not representative of the geological time‐scale deformations. Moreover, they suggest that a significant amount of stress is accommodated along the southern strand of the NAF system, on which the last large (M ≈ 7) earthquakes dates back to 1419, 1855 and 1863 AD.
The mRNA export factor Npl3 mediates the nuclear export of large ribosomal subunits
Authors: Hackmann Alexandra , Gross Thomas , Baierlein Claudia , Krebber Heike
Published: August 2011

The nuclear export of large ribonucleoparticles is complex and requires specific transport factors. Messenger RNAs are exported through the RNA‐binding protein Npl3 and the interacting export receptor Mex67. Export of large ribosomal subunits also requires Mex67; however, in this case, Mex67 binds directly to the 5S ribosomal RNA (rRNA) and does not require the Npl3 adaptor. Here, we have discovered a new function of Npl3 in mediating the export of pre‐60S ribosomal subunit independently of Mex67. Npl3 interacts with the 25S rRNA, ribosomal and ribosome‐associated proteins, as well as with the nuclear pore complex. Mutations in NPL3 lead to export defects of the large subunit and genetic interactions with other pre‐60S export factors.
Control over stress induces plasticity of individual prefrontal cortical neurons: A conductance-based neural simulation
Authors: Varela Juan , Wang Jungang , Varnell Andrew , Cooper Donald
Published: August 2011

Behavioral control over stressful stimuli induces resilience to future conditions when control is lacking. The medial prefrontal cortex(mPFC) is a critically important brain region required for plasticity of stress resilience. We found that control over stress induces plasticity of the intrinsic voltage-gated conductances of pyramidal neurons in the PFC. To gain insight into the underlying biophysical mechanisms of this plasticity we used the conductance- based neural simulation software tool, NEURON, to model the increase in membrane excitability associated with resilience to stress. A ball and stick multicompartment conductance-based model was used to realistically fit passive and active data traces from prototypical pyramidal neurons in neurons in rats with control over tail shock stress and those lacking control. The results indicate that the plasticity of membrane excitability associated with control over stress can be attributed to an increase in Na+ and Ca2+ T-type conductances and an increase in the leak conductance. Using simulated dendritic synaptic inputs we observed an increase in excitatory postsynaptic summation and amplification resulting in elevated action potential output. This realistic simulation suggests that control over stress enhances the output of the PFC and offers specific testable hypotheses to guide future electrophysiological mechanistic studies in animal models of resilience and vulnerability to stress.
Exploring The Hidden Realms Of Global Biodiversity: Interesting Endophytic Yeast Flora From Floral Ovaries
Authors: Kamat Nandkumar , Saudagar Shweta
Published: August 2011

Soil is considered the ultimate reservoir of all the microbiota and specifically the yeasts. However their association with different plant organs and at different developmental stages is not fully explored. Although about 1000 yeast species have been identified, exploration of various microhabitats such as plant storage organs, flowers, nectar, and tree sap is expected to yield a large number of novel species, including interesting endophytic yeasts(Carlos & Gabor, 2006). Angiosperms are considered the most diverse group of the plant kingdom comprising of about 250,000 species (Kenrick, 1999). As part of an exhaustive exploration of yeasts associated with angiosperm flowers, specific attention was paid to floral ovaries to detect the presence of endophytic yeast flora. A total of 52 flower species belonging to 25 families were sampled and screened for endophytic yeasts. Altogether ten viable yeast strains were obtained from seven flower species.
Ionization effects on the partitioning behavior of food and beverage aroma compounds between aqueous phases and air and organic matrices
Authors: Rayne Sierra , Forest Kaya
Published: August 2011

Aroma compounds in the Flavornet database were screened for ionizable functional groups such as carboxylic acids, aliphatic and aromatic amines, phenols, alcohols, and thiols. Of the 738 aroma compounds listed in this database, 101 molecules have ionizable moieties with estimated monomeric aqueous pK~a~ values ranging between 1.75 and 10.97. pH dependent effective air/water partitioning coefficients (K~aw,eff~) and n-octanol/water partitioning coefficients (D~ow~) were estimated for all ionizable aroma compounds over the pH range from 0 to 14. The ionizable aroma compounds display a broad range of K~aw,eff~ (1.8 × 10^-23^ to 6.1 atm M^-1^) and log D~ow~ (-6.2 to +7.2 units) values. For many aroma compounds, pH dependent ionization will have a significant effect on the K~aw,eff~ and D~ow~, leading to variations in these physico-chemical properties by up to 11 orders of magnitude over the composite pH range of common foods and beverages. Changes in food and beverage pH affect not only the relative contributions of neutral versus charged forms of ionizable aroma compounds (which directly affects analyte volatility and olfactory reception), but also partitioning between freely dissolved and sorbed forms of the analyte in solution (which indirectly affects analyte volatility).
The Horizontal and Stepped Osteotomy Technique for Mandibular Reconstruction Using Fibular Free Flap
Authors: Aleid Wesam , Jones Keith , Laugharne David
Published: August 2011

The mandible is an important component of the orofacial skeleton, and resection of part of the mandible as part of head and neck oncological procedures can have dramatic impact on both function and cosmesis. In this article, we describe a new technique in the resection osteotomy and flap fixation that improves the stability and aesthetic outcome of the reconstruction. The mandibular resection is performed utilizing a horizontal osteotomy above the mandibular angle on one side and a stepped body or angle osteotomy on the other side. Our technique is unique as it allows flexibility in adjusting the chin point projection to give the best possible aesthetic outcome; it allows more bone-to-bone contact, which increases the stability; it reduces rotation; and it allows for use of miniplate fixation, facilitating future rehabilitation with implants. We have been using this technique with great success in our hospital, and we recommend its use for its improved flexibility, stability, and aesthetic outcome.
An Aesthetically Possible Alternative Approach for Craniomaxillofacial Trauma: The “Pretrichial Incision”
Authors: Massarelli Olindo , Gobbi Roberta , Soma Damiano , Raho Maria Teresa , Tullio Antonio
Published: August 2011

Frontal sinus and supraorbital rim fractures are common in facial trauma patients. Coronal incision is the standard approach for surgical management of these injuries. Nevertheless, with this incision, complications can occur as wide scars and alopecia. Because surgical repair of fronto-orbital fractures is often indicated for aesthetic reasons, surgical incision might be an “aesthetic incision.” So we have adopted the pretrichial incision, already used in brow-lift and foreheadplasty but never described in craniomaxillofacial trauma surgery. Nineteen upper-third facial trauma patients were treated: five cases were approached via an existing laceration, four cases via a coronal incision, and 10 cases via a unilateral zigzag pretrichial incision. To assess the postsurgical scar, the Patient and Observer Scar Assessment Scale was used and the scar's width was measured. In all cases, a wide surgical field was obtained to perform correct fracture reduction. Unlike straight or stealth coronal incisions, with pretrichial incision no wide scar or alopecia was registered. We think that pretrichial incision is an aesthetically reasonable alternative to the standard coronal approach for craniomaxillofacial trauma patients.
Magnetite used to monitor functioning of human lung
Authors: Saar Robert A.
Published: August 2011

A new technique for monitoring lung contamination and function has been reported by David Cohen of the Francis Bitter National Magnet Laboratory (MIT). The diagnostic handle is magnetite dust, which normally occurs in such low levels in the lungs as to be measurable only in a magnetically shielded room with sophisticated apparatus. Higher amounts of magnetite dust in the lungs can be seen, though, even with a relatively simple and inexpensive flux-gate magnetometer.
The unity of physics
Authors: Amaldi Edoardo
Published: August 2011

What is the “unity of physics” and how far can it be accomplished? Before considering these questions let us look at a wider problem—the unification of all the sciences. This is itself a special case of an even wider question, the unification of all human knowledge, which I cannot dwell on here. The term “unification of the sciences” usually refers to a unification of the results obtained in the sciences; the problem of coordinating the scattered and immense body of specialized findings into a systematic whole is a real one and cannot be neglected. It includes a comparison of the methods and results of cosmology, geology, physics, biology, behavioral science, history and the social sciences in different ages. But first of all it implies a unification of scientific language. Some difficulties in science, even within a specialized discipline, arise because one cannot be sure whether two scientists speak about the same or different problems or whether they state the same or different opinions in their different scientific languages.
Exploring phase transformations with neutron scattering
Authors: Axe John D. , Shirane Gen
Published: August 2011

Phase transformations have for many years intrigued physicists as dramatic and yet subtle phenomena for study. In the early 1960's came the belated realization that there exists a particularly simple mechanism responsible for a certain class of structural transformations in solids. This mechanism involves an instability in a mode of vibration of the solid; that is, a “soft phonon” (one of low energy) is said to “condense” into the lattice to cause the phase transformation. The process is susceptible to experimental study even in complex structures and has given us a handle on the dynamics of this cooperative phenonenon. Here we will discuss such phase transformations, which have come to be called “displacive transformations,” and what can be learned about them by inelastic neutron-scattering experiments.
A theory of competitive running
Authors: Keller Joseph B.
Published: August 2011

World records for running provide data of physiological significance. In this article, I shall provide a theory of running that is simple enough to be analyzed and yet allows one to determine certain physiological parameters from the records. The theory, which is based on Newton's second law and the calculus of variations, also provides an optimum strategy for running a race.
Evidence accumulates for a black hole in Cygnus X-1
Authors: Lubkin Gloria B.
Published: August 2011

Within the past year many observers have become convinced that Cygnus X-1 contains a black hole. The most recent evidence, reported at the December meeting of the American Astronomical Society in Tucson, is from an x-ray detector aboard a rocket; a group at the Goddard Space Flight Center reported seeing millisecond variations in intensity, suggesting a compact object. Other recent evidence has come from observations with the 61-cm telescope at the Lick Observatory and from a group at University College London, who have an x-ray telescope aboard the Copernicus satellite. As the evidence has mounted, so has the excitement. However, there are many holdouts taking a wait-and-see attitude.
Nuclear-magnetism studies at Saclay
Authors: Lubkin Gloria B.
Published: August 2011

A unique research effort at Saclay, headed by Anatole Abragam, is using the method of dynamic nuclear polarization to study nuclear ferromagnetism and antiferromagnetism and to observe so-called pseudomagnetism. The experiments on nuclear ferromagnetism and antiferromagnetism have yielded spin temperatures of a microdegree Kelvin or lower, achieving a record low temperature duly recorded in the “Guinness Book of World Records.”
Two papers propose laser-induced fission
Authors: Lubkin Gloria B.
Published: August 2011

Over the past two years interest has been mounting over the idea of using a laser to compress a pellet and cause thermonuclear fusion (PHYSICS TODAY, August 1972, page 17 and August 1973, page 46). Now two papers, one from the Lebedev Institute and one from the University of Nevada, propose using a laser to compress a pellet of uranium and cause fission. Such an arrangement could be used to make a miniature fission reactor, an intense neutron source, a particle accelerator or a very intense magnetic field, the authors say.
Copyrighting physics journals
Authors: Koch H. William
Published: August 2011

Changes in the manner of publishing and disseminating physics information have been coming faster and faster during the last decade or so, and with them they have brought an increasingly urgent need for changes in copyrighting procedures and practices. Every user of American Institute of Physics and its member societies’ journals is bound to be affected in some way, as will be the authors contributing to the journals, when journal copyright ambiguities and inconsistencies are clarified. Will the individual physicist, or his library, be able to continue purchasing primary journals and secondary-information products at fair market prices—or will he be subsidizing the commercial use of these products in some other form, or in some other country? Will the one quarter of all AIP society members who (according to one count) themselves contribute, as authors, to the physics literature at some time or other be completely clear as to their rights to protect the scientific integrity of their own published works? Or will they find that questions concerning the re-use of their works dissolve into a fog of international disagreements?.
Why the sky is dark at night
Authors: Harrison Edward R.
Published: August 2011

Let us imagine that stars similar to the Sun are uniformly distributed in an infinite and static universe. Edmund Halley in 1720, J. P. Loys de Chéseaux in 1744, and H. Wilhelm M. Olbers in 1823 showed this seemingly reasonable 16th and 17th century model of the universe leads to a remarkable paradox. For whatever direction we look in the sky our line of sight eventually intercepts a star, and the whole sky should therefore be ablaze with light as bright as the Sun. This startling disagreement between theory and observation is nowadays referred to as “Olbers's paradox.”
Diffusion-influenced ligand binding to buried sites in macromolecules and transmembrane channels
Authors: Berezhkovskii Alexander M. , Szabo Attila , Zhou Huan-Xiang
Published: August 2011

We consider diffusion-influenced binding to a buried binding site that is connected to the surface by a narrow tunnel. Under the single assumption of an equilibrium distribution of ligands over the tunnel cross section, we reduce the calculation of the time-dependent rate coefficient to the solution of a one-dimensional diffusion equation with appropriate boundary conditions. We obtain a simple analytical expression for the steady-state rate that depends on the potential of mean force in the tunnel and the diffusion-controlled rate of binding to the tunnel entrance. Potential applications of our theory include substrate binding to a buried active site of an enzyme and permeant ion binding to an internal site in a transmembrane channel.
Wetting of bulk metallic glass forming liquids on metals and ceramics
Authors: Ding Shiyan , Kong Jian , Schroers Jan
Published: August 2011

Contact wetting angle of Pd43Ni10Cu27P20, Pt57.5Cu14.7Ni5.3P22.5, Au49Ag5.5Pd2.3Cu26.9Si16.3, and Zr57Nb5Cu15.4Ni12.6Al10 bulk metallic glass forming alloys have been determined on materials that are used in micro and nano fabrication. Employing the sessile drop technique at a temperature above the corresponding melting temperatures, three kinds of wetting behaviors are observed, spanning from θ ≈ 140°, over neutral wetting, θ ≈ 80°, to almost complete wetting, θ < 5°. The origin for complete wetting is the formation of an interface phase promoting wetting. Estimations of the contact wetting angles are presented for temperatures in the supercooled liquid region where micro and nano fabrication is typically carried out. Consequences of the observed wetting behaviors for nanoforming are discussed.
Some Hamiltonian models of friction
Authors: Fröhlich Jürg , Gang Zhou , Soffer Avy
Published: August 2011

Mathematical results on a model describing the motion of a tracer particle through a non-interacting Bose-Einstein condensate are described. In the limit of a very dense gas and for a very large particle mass, the dynamics of the coupled system is determined by classical nonlinear Hamiltonian equations of motion. The particle's motion exhibits deceleration corresponding to friction with memory caused by the emission of Cerenkov radiation of gapless modes into the gas. A more general class of models involving interacting Bose gases will be studied in forthcoming papers.
Frequency hopping due to acousto-electric interaction in ZnO based surface acoustic wave oscillator
Authors: Dasgupta Daipayan , Sreenivas K.
Published: August 2011

A 36 MHz surface acoustic wave delay line based oscillator has been used to study the effect of acousto-electric interaction due to photo generated charge carriers in rf sputtered ZnO film under UV illumination (λ = 365 nm, 20–100 μW/cm2). Design aspects for developing a delay line based SAW oscillator are specified. The observed linear downshift in frequency (2.2 to 19.0 kHz) with varying UV intensity (20–100 μW/cm2) is related to the fractional velocity change due to acousto-electric interaction. UV illumination level of 100 μW/cm2 leads to a characteristic frequency hopping behavior arising due to a change in the oscillation criteria, and is attributed to the complex interplay between the increased attenuation and velocity shift.
A branched luminescent multinuclear platinum(II) complex
Authors: Yang Hui , Xu S. J. , Tao Chi-Hang , Yam Vivian Wing-Wah , Zhang Jie
Published: August 2011

Nonlinear optical properties of luminescent multinuclear platinum(II) complex of branched alkynyls in benzene solution are investigated at room temperature by using two-photon fluorescence (TPF) technique. It is found that the material shows unusual nonlinear optical characteristics under the excitation of near infrared femtosecond laser pulses. The self-focusing of laser beam energy during propagation of the laser pulses in the sample with large nonlinear coefficient for the refractive index is observed. Based on this phenomenon, a new method for measuring the nonlinear coefficient and two-photon absorption cross section of materials is proposed.
The pulsrodon in 2+1-dimensional magneto-gasdynamics: Hamiltonian structure and integrability
Authors: Rogers C. , Schief W. K.
Published: August 2011

An elliptic vortex-type ansatz introduced into a 2+1-dimensional system governing rotating homentropic magneto-gasdynamics with a parabolic gas law is shown to lead to a finite-dimensional nonlinear dynamical system which admits exact analytical solution in terms of an elliptic function and integral representation. The dynamical system is demonstrated to be Hamiltonian and equivalent to the stationary reduction of the integrable nonlinear Schrödinger equation coupled with a Steen-Ermakov-Pinney equation. A novel magneto-gasdynamic analogue of the pulsrodon of shallow water f-plane theory is isolated thereby. Confined and time-periodic magneto-gasdynamic flows are constructed explicitly.
Three-dimensional broadband and high-directivity lens antenna made of metamaterials
Authors: Chen Xi , Feng Ma Hui , Ying Zou Xia , Xiang Jiang Wei , Jun Cui Tie
Published: August 2011

We present the theoretical modeling and prototype demonstration of a three-dimensional broadband, low-loss, dual-polarization, and high-directivity lens antenna using gradient index (GRIN) metamaterials, which is composed of multi-layer microstrip square-ring arrays. The elements of metamaterials, closed square-ring units of variable sizes, are distributed on the planar substrate to satisfy the radial gradient index function and the axial impedance matching layer configuration of the lens. The gradient-index metamaterials are designed to transform the spherical wave-front into the planar wave-front and to minimize the reflection loss. A prototype lens antenna, which consists of a metal conical horn and the gradient-index lens, are simulated, constructed, and measured. The resemblance of simulation and measurement results shows that the prototype lens antenna maintains low return loss and high directivity on the whole X-band (from 8 GHz to 12 GHz). Compared to the traditional horn antenna, the metamaterial GRIN lens antenna has much superior performance—for instance, the gain increases by 6 dBi at 12 GHz. These results demonstrate the feasibility of such a light weight slab metamaterial lens for broadband and high-directivity antenna applications, such as in radar and communication systems. We have used the lens antennas in the measurements of a three-dimensional invisibility cloak due to the high directivity.
Void evolution in polycarbonate at elevated temperatures
Authors: Chen Y. H. , Feng Chou Kuo , Li C. L. , Lee Sanboh
Published: August 2011

The void evolution in polycarbonate (PC) at elevated temperatures was investigated. Internal cylindrical cracks and voids were induced in PC by Nd-YAG laser irradiation. During the annealing at temperatures of 177–197 °C, the spherical void grows to a maximum size, which then decreases, and is finally leveling off. A model of void evolution based on the evaporation and condensation mechanisms for growth and shrinkage is proposed. The theoretical predictions are in good agreement with the experimental data. The activation energies of evaporation and condensation processes are determined to be 477.31 and 611.49 kJ/mol, respectively.
Photonic crystal cavity with one-way rotating state and its coupling with photonic crystal waveguide
Authors: Wang Zhuoyuan , Shen Linfang , Zhang Xianmin , Wang Yigang , Yu Zaihe , Zheng Xiaodong
Published: August 2011

A photonic crystal (PhC) cavity formed by a closed interface between a dielectric PhC and a magnetooptical (MO) material PhC is proposed and analyzed theoretically. It is shown that such a cavity can support one-way rotating modes and thus the modal fields at different frequencies have a similar pattern. The loss effect of MO material is taken into consideration for the solution of quality-factors for the cavity. The coupling between a cavity with one-way state and a PhC waveguide is also studied through numerical simulations. Simulation results show that cavity mode only interacts with the waveguide mode propagating in a particular direction. This work paves the way to control waveguide-cavity interaction.
An LIF characterization of supersonic BO (X2Σ+) and CN (X2Σ+) radical sources for crossed beam studies
Authors: Maksyutenko Pavlo , Parker Dorian S. N. , Zhang Fangtong , Kaiser Ralf I.
Published: August 2011

Various ablation sources generating supersonic boron monoxide (BO; X2Σ+) radical beams utilizing oxygen (O2), carbon dioxide (CO2), methanol (CH3OH), and water (H2O) as seeding gases were characterized in a crossed molecular beams setup by mass resolved time-of-flight spectroscopy and spectroscopically via laser induced fluorescence. Intensities of the sources as well as rovibrational energy distributions were analyzed. The molecular oxygen source was found to produce excessive amount of an unwanted BO2 byproduct. Internal vibrational energy of boron monoxide generated in the water and methanol sources was too high to be considered for the study of dynamics of ground state radicals. The best combination of intensity, purity, and low internal energy was found in the carbon dioxide source to generate boron monoxide. We successfully tested the boron monoxide (BO; X2Σ+) radical beam source in crossed beams reactions with acetylene (C2H2) and ethylene (C2H4). The source was also compared with supersonic beams of the isoelectronic cyano (CN; X2Σ+) radical.
Note: Demonstration of an external-cavity diode laser system immune to current and temperature fluctuations
Authors: Miao Xinyu , Yin Longfei , Zhuang Wei , Luo Bin , Dang Anhong , Chen Jingbiao , Guo Hong
Published: August 2011

We demonstrate an external-cavity laser system using an anti-reflection coated laser diode as gain medium with about 60 nm fluorescence spectrum, and a Rb Faraday anomalous dispersion optical filter (FADOF) as frequency-selecting element with a transmission bandwidth of 1.3 GHz. With \documentclass[12pt]{minimal}\begin{document}$\rm{6.4\%}$\end{document}6.4% optical feedback, a single stable longitudinal mode is obtained with a linewidth of 69 kHz. The wavelength of this laser is operating within the center of the highest transmission peak of FADOF over a diode current range from 55 mA to 142 mA and a diode temperature range from 15 °C to 35 °C, thus it is immune to the fluctuations of current and temperature.
Development of a real time monitor and multivariate method for long term diagnostics of atmospheric pressure dielectric barrier discharges: Application to He, He/N2, and He/O2 discharges
Authors: O’Connor N. , Milosavljević V. , Daniels S.
Published: August 2011

In this paper we present the development and application of a real time atmospheric pressure discharge monitoring diagnostic. The software based diagnostic is designed to extract latent electrical and optical information associated with the operation of an atmospheric pressure dielectric barrier discharge (APDBD) over long time scales. Given that little is known about long term temporal effects in such discharges, the diagnostic methodology is applied to the monitoring of an APDBD in helium and helium with both 0.1% nitrogen and 0.1% oxygen gas admixtures over periods of tens of minutes. Given the large datasets associated with the experiments, it is shown that this process is much expedited through the novel application of multivariate correlations between the electrical and optical parameters of the corresponding chemistries which, in turn, facilitates comparisons between each individual chemistry also. The results of these studies show that the electrical and optical parameters of the discharge in helium and upon the addition of gas admixtures evolve over time scales far longer than the gas residence time and have been compared to current modelling works. It is envisaged that the diagnostic together with the application of multivariate correlations will be applied to rapid system identification and prototyping in both experimental and industrial APDBD systems in the future.
Suppression of ferromagnetism and metal-like conductivity in lightly Fe-doped SrRuO3
Authors: Fan Jiyu , Liao Sicheng , Wang Wenqin , Zhang Lei , Tong Wei , Ling Langsheng , Hong Bo , Shi Yangguang , Zhu Yan , Hu Dazhi , Pi Li , Zhang Yuheng
Published: August 2011

The magnetic and electronic transport properties of the lightly doped SrRu1-xFexO3 (x ≤ 0.15) have been studied. All the samples show a paramagnetic-ferromagnetic phase transition and hysteresis effect. With the increase of Fe, the temperature of magnetic phase transition decreases but coercive field increases indicting the existence of antiferromagnetic interaction and magnetic-crystalline anisotropy. In low temperature, all the doping samples exhibit an insulating behavior while metal feature appears only at x ≤ 0.10 samples. The induced disorder suppresses the itinerant property of Ru 4d electron due to Fe random occupation. As a result, the ferromagnetism is weakened and metal-insulator transition is suppressed.
The performance and relationship among range-separated schemes for density functional theory
Authors: Nguyen Kiet A. , Day Paul N. , Pachter Ruth
Published: August 2011

The performance and relationship among different range-separated (RS) hybrid functional schemes are examined using the Coulomb-attenuating method (CAM) with different values for the fractions of exact Hartree-Fock (HF) exchange (α), long-range HF (β), and a range-separation parameter (μ), where the cases of α + β = 1 and α + β = 0 were designated as CA and CA0, respectively. Attenuated PBE exchange-correlation functionals with α = 0.20 and μ = 0.20 (CA-PBE) and α = 0.25 and μ = 0.11 (CA0-PBE) are closely related to the LRC-ωPBEh and HSE functionals, respectively. Time-dependent density functional theory calculations were carried out for a number of classes of molecules with varying degrees of charge-transfer (CT) character to provide an assessment of the accuracy of excitation energies from the CA functionals and a number of other functionals with different exchange hole models. Functionals that provided reasonable estimates for local and short-range CT transitions were found to give large errors for long-range CT excitations. In contrast, functionals that afforded accurate long-range CT excitation energies significantly overestimated energies for short-range CT and local transitions. The effects of exchange hole models and parameters developed for RS functionals for CT excitations were analyzed in detail. The comparative analysis across compound classes provides a useful benchmark for CT excitations.
Charge carrier extraction dynamics for organic field effect transistor structures
Authors: Chang Hsiu-Chuang , Paul Ruden P. , Liang Yan , Daniel Frisbie C.
Published: August 2011

We present experimental data and a model for charge carrier extraction from the channel of a device structure resembling an organic field effect transistor. The initially accumulated channel is depleted by a sudden change of the gate voltage. The measured discharge current transient decreases either as a power law or exponentially if the final state of the channel is completely or partially depleted, respectively. The extraction process is modeled with a capacitor/resistor circuit with a time-dependent resistance that increases with decreasing channel carrier density. Analytical and numerical results are discussed and compared with the experimental data.
The application of fixed hydrophobic patterns for confinement of aqueous solutions in proteomic microarrays
Authors: Li Y. , McKenna E. O. , Parkes W. , Pitt A. R. , Walton A. J.
Published: August 2011

A protein microarray hybridisation system has been implemented by employing patterned hydrophobic thin films on hydrophilic substrates as a means of confinement for aqueous samples. This approach has the ability to handle, and keep separate, small sample volumes of just a few microlitres. In addition, the system is more straightforward to use than the existing multi-well gasket solution. The paper describes the fabrication method and the system is demonstrated for a model protein microarray assay.