bluuebunny/crossref_metadata_2025 huggingface dataset:
Post-disturbance dynamics of plant communities in a Mediterranean temporary pool (Western Morocco): Effects of disturbance size
Authors: Sahib Nargis , Rhazi Laïla , Grillas Patrick
Published: February 2011

Mediterranean temporary pools are frequently visited habitats where domestic livestock and wild herbivores generate numerous physical soil disturbances. Using two sizes of experimental plots (large, 1.20 m × 1.20 m; small, 0.3 m × 0.3 m), the effects of soil disturbances on vegetation dynamics and the vertical distribution of seeds were studied in one Moroccan temporary pool. Results show a very rapid regeneration of temporary wetland vegetation in disturbed plots. The speed of regeneration depends on the size of disturbance and hydrology. There was an almost complete return of vegetation to the reference state in the small disturbed plots by the end of the 1st year. This fast restoration was mainly due to seed banks, which play a key role in the resilience of pools to the different sizes of disturbances frequently generated by herbivores, but also to lateral colonization by perennials.
Spatial and temporal deposition of suberin during maturation of the onion root exodermis
Authors: Meyer Chris J. , Peterson Carol A. , Bernards Mark A.
Published: February 2011

Suberin is a complex biopolymer composed of a poly(aliphatic) domain (SPAD) and a poly(phenolic) domain (SPPD). Suberin is typically confined to specialized cell types including root exodermal cells, but its synthesis in a maturing exodermis is still not well understood. For the current work, Allium cepa roots were used as a model to analyze SPAD and SPPD synthesis in a maturing uniseriate exodermis. Roots were divided into four maturation zones based on their growth rate and the deposition of suberin lamellae in maturing exodermal cells. Exodermal and epidermal cell layers were separated from the underlying layers in each maturation zone, then soluble and insoluble suberin monomers were extracted chemically, and quantified and identified by gas chromatography – mass spectrometry. Temporal patterns for the synthesis of the SPAD, but not for the SPPD, were revealed upon resolution of the metabolite profiles. The composition of the soluble fraction was essentially unchanged as the exodermis matured. In contrast, the SPAD composition differed during maturation, mainly owing to significant increases in the deposition of C18:1 α,ω-dioic acid and ω-OH fatty acids. It is proposed that the exodermal maturation zones with their corresponding metabolite profiles be used as targets for the functional enzymatic characterization of suberin biosynthetic pathways.
Clonal and nonclonal genetic structure of subarctic black spruce (Picea mariana) populations in Yukon territory
Authors: Viktora Marios , Savidge Rodney A. , Rajora Om P.
Published: February 2011

Black spruce (Picea mariana) reproduces sexually from seeds and asexually by layering. There is a prevalent concept that clonal reproduction maintains populations of this species in the subarctic and arctic regions. We used microsatellite DNA markers of the nuclear genome to investigate the genetic structure of montane and subalpine black spruce populations from the Western Yukon Plateau in relation to this concept. Sixty individual trees at a minimum distance of 4 m from each other were sampled from each of four populations and individual trees were genotyped for eight microsatellite loci. Each of the 60 individuals from three montane pure black spruce populations growing on flat terrain at relatively low elevations had unique multilocus genotypes, indicating an absence of clonal structure in those populations. However, in an anthropologically undisturbed climax white spruce-dominated subalpine black spruce population on a northwest slope near Mount Nansen, the majority of the sampled individuals belonged to eight genetically distinct clones (genets). Clone size differed by altitude, the dominant genet being nearest the timberline–tundra ecotone. The results indicate that black spruce reproduction is variable and adaptive, being primarily sexual in flat-terrain montane populations previously subjected to fire disturbance, but mixed vegetative–sexual in the anthropogenically undisturbed subalpine population. This study is the first to employ molecular markers a priori to examine the mode of reproduction in natural black spruce populations.
Quantum equations from Brownian motion
Authors: Rajput B. S.
Published: February 2011

The Schrödinger free particle equation in 1+1 dimension describes second-order effects in ensembles of lattice random walks, in addition to its role in quantum mechanics, and its solutions represent the continuous limit of a property of ensembles of Brownian particles. In the present paper, the classical Schrödinger and Dirac equations have been derived from the Brownian motions of a particle, and it has been shown that the classical Schrödinger equation can be transformed into the usual Schrödinger quantum equation on applying the Heisenberg uncertainty principle between position and momentum, while the Dirac quantum equation follows from its classical counterpart on applying the Heisenberg uncertainty principle between energy and time, without applying any analytical continuation.
Generalization and extension of the angular density representation in neutron transport analysis
Authors: Harms Archie A.
Published: February 2011

A generalization of the angular density representation, designated by the acronym NPL, is formulated within the context of one-group neutron transport theory. The distinguishing feature of this formalism consists of the use of partial-range Legendre polynomials over arbitrary intervals of the angular variable. This NPL formalism is subsequently examined for its orthogonality and recurrence properties. It is further shown that several widely used solution methods of one-group neutron transport theory are but special cases of this more inclusive representation.An indication of the computational usefulness of this NPL representation is demonstrated by calculating the inverse diffusion length. Using a low-order approximation it is found that by a suitable choice of the angular segmentation, better numerical accuracy may be obtained in highly absorbing media when compared with alternative methods of comparable complexity.The NPL formalism may be viewed as a continuation of the analytical trend which led from the PL to the DPL formalism. Alternatively, it may be viewed as a natural consequence of the desirability to specify angular structures specifically adapted to problems of neutron transport involving highly varying angular densities. Deep neutron penetration calculations represent one such class of problems.
Decay of the O I λ5577 line in meteor wakes
Authors: Gault W. A.
Published: February 2011

Multiple-exposure spectra of six meteors showing the auroral green line of atomic oxygen have been measured photometrically. The decay of the green line is described in terms of two parameters which are given as functions of height. It is shown that the maximum intensity occurs after a measurable time interval, which varies from 0.3 s at 115 km to 0.06 s at 105 km and decreases further with decreasing height. The subsequent decay rate is close to the natural rate (1 s−1) of the 1S state above 110 km, but increases with decreasing height to 3 s−1 at 100 km. The height of the green-line emission is consistent with most previous measurements, and corresponds with the height of the atmospheric atomic oxygen layer. The observations do not show a correlation of green-line characteristics with geomagnetic activity. Various possible excitation and quenching mechanisms are discussed.
Backscatter currents from thin Ag films under bombardment by atomic projectiles
Authors: Wijngaarden A. van , Miremadi B. , Brimner E. J. , Bradford J. N.
Published: February 2011

Thin Ag films formed by vacuum deposition on a low Z backing material were irradiated by keV ion beams of 1H, 14N, and 40Ar. The backscatter current yield was measured with a collector plate, kept at a negative potential. For 1H, the backscatter yield increases rapidly with film thickness while for 40Ar projectiles, the yield arises mainly from a thin surface layer. The maximum depth contributing to the backscatter current yield is of the same order as the projected range in the target material. Arguments are presented that the depths involved in backscatter currents and in sputtering will be of comparable importance.
Input impedance approximations for small dipole and loop antennas near ground
Authors: Vogler L. E.
Published: February 2011

Approximate expressions for the input impedances of small vertical and horizontal dipole and loop antennas above a conducting ground plane are developed. The formulas give increasingly accurate impedance estimates as [Formula: see text], where N is the refractive index of the ground. A comparison with the exact solution for a specific case, [Formula: see text] and varying antenna heights, is given.
Hydrogen positions in potassium pentaborate tetrahydrate as determined by neutron diffraction
Authors: Ashmore J. P. , Petch H. E.
Published: February 2011

Neutron diffraction data obtained with single crystals of potassium pentaborate tetrahydrate have been analyzed using least squares methods. Apart from significant differences in the atomic coordinates of the hydrogen atoms, the structure is in agreement with recent X-ray work. The O—H distances in the hydroxyl groups are 1.012 ± 0.018 and 0.955 ± 0.020 Å. In contrast to the X-ray results, the geometry of the water molecule is normal for an inorganic hydrate with O—H distances of 0.954 ± 0.026 and 1.004 ± 0.018 Å and an H—O—H angle of 108 ± 2°.
Axial backscattering from an absorbing finite cone
Authors: Bowman John J.
Published: February 2011

The high-frequency, backscattering cross section for axial incidence on a highly absorbing, flat-based cone is obtained. The cone is assumed to obey an impedance boundary condition. The tip contribution is neglected, while the leading term in the base contribution is derived by means of wedge diffraction theory where the wedge has arbitrary face impedances. Surprisingly, the result is relatively simple.
Ferromagnetic resonance in iron whiskers
Authors: Kambersky V.
Published: February 2011

Results are reported for the line width of the ferromagnetic resonance in pure iron whiskers. Line widths were measured at 24.5, 35, and 73 GHz and at room temperature and 4.2 °K. An unsuccessful attempt was made to detect the antiresonance at ω = γB, where γ is the spectroscopic splitting factor of the electron spins in iron.
Raman spectra of CdF2 and PbF2
Authors: Krishnamurthy N. , Soots V.
Published: February 2011

The first-order Raman spectra of CdF2 and PbF2 have been recorded at 300, 77, and 4.2 °K. The spectrum in each case is a single line, arising from the triply degenerate F2g lattice mode. The observed frequency of this mode is 315 cm−1 in CdF2 and 257 cm−1 in PbF2. The frequencies shift slightly and the lines narrow considerably when the crystals are cooled. The Raman frequencies are used, together with previously known infrared and elastic data, to calculate the parameters of the rigid ion and the dipole shell models for these crystals.
STRUCTURE AND MAGNETIC PROPERTIES OF NANOSIZED Y2O3–Fe2O3 MIXTURE
Authors: JAAFAR ADNAN , AL-SAIE AHMED , BOUOUDINA MOHAMED
Published: February 2011

Mechanical alloying of a mixture of Fe2O3 and Y2O3 was used in order to produce a single nanocrystalline YFe2O4 phase. After milling the diffraction characteristic peaks become broader and their relative intensity is reduced due to the particles size reduction and accumulation of microstrains. Diffraction peaks related to Y2O3 phase disappeared. After annealing at 1200°C, new peaks appeared and identified as Y3Fe5O12 phase. Magnetic properties measurements reveal that after annealing, saturation magnetization increased dramatically compared to as milled powders. Moreover, the Y3Fe5O12 shows a superferromagnetic behavior, with Ms ≈ 22 emu/g , Hc ≈ 14.5 Oe , Mr ≈ 1.56 emu/g and a crystallites size around 151 nm.
THE EFFECTS OF OPFB SIZE ON THE MECHANICAL PROPERTIES OF OIL PALM FRUIT BUNCH FIBRE FILLED POLYPROPYLENE–CLAY NANOCOMPOSITES
Authors: KALAM ANIZAH , BERHAN MOHAMAD NOR , ISMAIL HANAFI
Published: February 2011

Oil palm fruit bunch (OPFB) fibre was used as filler in polypropylene–clay nanocomposite (PNC) to study its effect on the mechanical properties of OPFB filled PNC or hybrid polymer nanocomposite (HPNC). The OPFB size was varied at 250 μm, 180 μm, 125 μm and 100 μm. HPNC was prepared by compounding 20 wt.% of OPFB together with PNC. Tensile, flexural and impact test samples were injection moulded from the compounds according to ASTM standards. The experimental results showed that the increase of OPFB size in HPNC has increased the tensile and flexural moduli from 39% to 54% and 33% to 69%, respectively. Meanwhile, the tensile and flexural strengths increased as the OPFB size increases. The elongation at break and impact resistance were not affected by OPFB size. Scanning electron microscope result showed that the fracture surfaces of coarser OPFB filled polypropylene–clay nanocomposite has several mechanisms such as fibre pull-outs, fibre fracture and fibre delamination, whereas the PNC filled with finer OPFB exhibited ductile fracture.
SYNTHESIS AND CHARACTERIZATION OF MICROPOROUS SILICA-ALUMINA THIN FILMS
Authors: ABDALLAH CHERAITIA , HAMID SATHA , ANDRÉ AYRAL
Published: February 2011

Microporous silica-alumina thin films were prepared by a simple and robust sol-gel method. Tetraethoxysilane was mixed with an acidic alumina hydrosol. Urea was added for the preparation of the alumina hydrosol, for controlling the polycondensation of the mixed oxide network and also as porogen agent. Thin films were deposited by dip-coating on dense substrates.

IR and 27 Al NMR spectroscopic analyses showed that for Si/Al molar ratios up to 6/1, a homogeneous mixed oxide is obtained with a random distribution of Al and Si atoms in the oxide lattice based on tetrahedral units. The deposited layers are crack-free as demonstrated by scanning electron microscopy (SEM) observations. Their microporosity was investigated using ellipsoporosimetry (EP) with films supported on flat substrates.
THE STRUCTURE AND MAGNETIC PROPERTIES OF ZnCr2-xFexO4
Authors: AL-SAIE AHMED M.
Published: February 2011

ZnCr 1-x Fe x O 4 system (with x = 0, 0.5, 1, 1.5, and 2) at the nanoscale has been successfully synthesized by a simple combination of milling mixture of Zn , Cr , and Fe oxides precursors. X-ray diffraction and magnetic measurements were carried out on the as-milled powders. XRD pattern clearly shows that the mixed oxides are all nanosized. However, as Fe 2 O 3 increases the ZnCrFeO 4 phase becomes the main phase. However, magnetic measurements do not show any significance in saturation magnetization (Ms), only when the content of Fe becomes 50% and 0.75% the Ms increased drastically to 15.4 and 16.7 emu/g respectively. However, with Fe 75% He and Mr reduced abruptly to half of their values, showing a ferromagnetic behaviour with low He .
CHEMICALLY DEPOSITED HETEROJUNCTION SOLAR CELLS Pb(1-x)Cd(x)S(n)/Si(p)
Authors: ABDELHAMID OUNISSI , NADIA OUDDAI
Published: February 2011

The fimls of Pb (1-x) Cd (x) S have been prepared on glass substrates by chemical method. The optical study of transmission T(λ) and reflexion R(λ) spectra has enabled us to determine the compounds whose gap is close to 1.5 eV. The heterojunction is obtained by the chemical deposition of the Pb (1-x) Cd (x) S films grown on the p-type Silicon substrates (7 Ω cm). The preparation conditions of the ternary compound whose gap is 1.48 eV have been used to achieve the heterojunction Pb (1-x) Cd (x) S - n/Si - p , and we have studied the effect of thermal treatment on the prepared heterojunction. X-ray diffraction has been used to determine the variation of the crystalline parameter, the ratio of cadmium in the compound Pb (1-x) Cd (x) S and the dependence of the gap on the cadmium composition. C–V characteristics were examined to understand the average concentration of impurities in the compound Pb (1-x) Cd (x) S .
ELECTRONEGATIVITY EFFECTS ON THE BANDGAP BOWING CHARACTERS IN COMPOUND-SEMICONDUCTOR TERNARY ALLOYS
Authors: TIT NACIR , AMRANE NOUREDDINE , RESHAK ALI HUSSAIN
Published: February 2011

We present a theoretical investigation of the existence and origins of the bandgap bowing character in compound semiconductor alloys based on both the sp3s*-tight-binding (TB) method, which includes the spin–orbit coupling, and the first-principle Full-Potential Linear Augmented Plane Wave (FP-LAPW) technique. First, we compare the bandgap variation versus composition in the III–V direct-bandgap- GaAs -based ternary alloys, namely between the common-cation GaSb x As 1-x and the common-anion Ga 1-x In x As ternary alloys. The results show that the bowing behavior exists only in the common-cation (i.e., GaSbAs ) alloys as a result of an existing competition between the anion atoms ( Sb and As ) in trapping the electronic charge. The bowing parameter is found to be proportional to the electronegativity characters of the competing anions (i.e., χanion). The lack of such competition, in the case of common-anion alloys (i.e., GaInAs ), makes the bowing be just absent and the variation of the bandgap become close to linear. Second, we have made a clear contrast in the bowing characters between the common-cation III–V and the common-anion II–V ternary alloys by assessing the effect of anion electronegativity (as example, we consider the GaSb x As 1-x and CdSe x Te 1-x ternary alloys). The results show that the bowing character in the II–VI alloys is stronger than the one of III–V alloys as to be simultaneously proportional to the electronegativity of anions ([Formula: see text]) and to the electronegativity mismatch between them ([Formula: see text]). Finally, the excellent agreement between our theoretical results and recent photoluminescence data has further corroborated our claims.
WEHRL ENTROPY OF A MIXED STATE THREE-LEVEL ATOM INTERACTING WITH A CAVITY FIELD
Authors: ABDEL-KHALEK S. , HASSOUNI Y. , ABDEL-ATY M.
Published: February 2011

In this paper, the Wehrl entropy approach is discussed and compared with the quantum entanglement using a mixed-state three-level atom interacting with a cavity field. In the pure state case, the behavior of the atomic Wehrl entropy shows the same behavior of the entanglement due to the von-Neumann entropy, while the mixed state case gives the total correlation due to quantum mutual entropy. If the system is in an entangled state, the formalism can be used to quantify the entanglement as well as the total correlations.
Charge-Sensitive Infrared Phototransistors Developed in the Wavelength Range of 10–50 µm
Authors: Ueda Takeji , Soh Yuki , Nagai Naomi , Komiyama Susumu , Kubota Hiroshi
Published: February 2011

Charge-sensitive infrared phototransistors (CSIPs) have been developed in a wavelength range of 12 to 45 µm by using double-quantum-well GaAs/AlGaAs heterostructures. Important parameters for designing the devices are discussed. The detectors are operated at 4.2 K. Quantum efficiency is affected by the crystal quality, which is supposed to be primarily determined by the imperfection in barrier regions. The specific detectivity, substantially determined by the quantum efficiency, is in the range of D
* = 1012–1016 cm Hz1/2/W.
Electric Field Induced Carrier Sweep-Out in Tandem InGaN Multi-Quantum-Well Self-Pulsating Laser Diodes
Authors: Kawaguchi Yoshinobu , Tani Yoshihiko , Vaccaro Pablo O. , Ito Shigetoshi , Kawanishi Hidenori
Published: February 2011

Mechanisms of carrier sweep-out in tandem InGaN multiple-quantum-well self-pulsating laser diodes were investigated. Laser diodes showed self-pulsating characteristics without significant change in the light output–current (I–L) characteristics when an electric field high enough was established in the saturable absorber by the applied reverse bias. Improvements in the design of the band-energy profile allowed a substantial reduction in the bias required for self-pulsating operation. These results indicate that carrier lifetime can be controlled by the electric field in the saturable absorber and that band-energy profile engineering is effective for the reduction of carrier lifetime.
Simplified Boundary Modeling for Resonating Structures by Scattering Analysis
Authors: Thalmayr Florian , Hashimoto Ken-ya , Ueda Masanori , Omori Tatsuya , Yamaguchi Masatsune
Published: February 2011

In this paper, we discuss a simplified boundary modeling for numerical simulation of complex real resonator devices by prior scattering analysis. Appropriate boundary conditions are a crucial factor for accurate simulation of resonator devices. We propose to analyze the scattering of propagating eigenmodes at the substrate-to-membrane anchor of the resonating structure and show that model simplification is feasible, provided that the backscattered energy at the anchor/substrate boundary is small and the contribution of energy tunneling by evanescent modes is negligible. Exemplarily, we analyze the model of a film bulk acoustic resonator (FBAR).
Simultaneous Formation of Both Single- and Multi-Wall Carbon Nanotubes by Ultrasonic Spray Pyrolysis
Authors: Khatri Ishwor , Kishi Naoki , Zhang Jianhui , Soga Tetsuo , Jimbo Takashi
Published: February 2011

In this paper, we report the simultaneous formation of both single-walled carbon nanotubes (SWCNTs) and multi-wall carbon nanotubes (MWCNTs) in a reactor by ultrasonic spray pyrolysis. MWCNTs were formed at the center of the tube since catalyst particles accumulated on the substrates at the center agglomerate into a larger size. However, SWCNTs were formed downstream of the tube on desired substrates. Light transmission of the fluorine-doped tin oxide (FTO) substrate is reduced after SWCNT formation but returns to its initial state after ozone treatment.
Weighted Anisotropic Integral Representations of Holomorphic Functions in the Unit Ball of Cn
Authors: Karapetyan Arman
Published: February 2011

We obtain weighted integral representations for spaces of functions holomorphic in the unit ball Bn and belonging to area‐integrable weighted Lp‐classes with “anisotropic” weight function of the type , w = (w1, w2, …, wn) ∈ Bn. The corresponding kernels of these representations are estimated, written in an integral form, and even written out in an explicit form (for n = 2).
Porcine and Canine von Willebrand Factor and von Willebrand Disease: Hemostasis, Thrombosis, and Atherosclerosis Studies
Authors: Nichols Timothy C. , Bellinger Dwight A. , Merricks Elizabeth P. , Raymer Robin A. , Kloos Mark T. , DeFriess Natalie , Ragni Margaret V. , Griggs Thomas R.
Published: February 2011

Use of animal models of inherited and induced von Willebrand factor (VWF) deficiency continues to advance the knowledge of VWF-related diseases: von Willebrand disease (VWD), thrombotic thrombocytopenic purpura (TTP), and coronary artery thrombosis. First, in humans, pigs, and dogs, VWF is essential for normal hemostasis; without VWF bleeding events are severe and can be fatal. Second, the ADAMTS13 cleavage site is preserved in all three species suggesting all use this mechanism for normal VWF multimer processing and that all are susceptible to TTP when ADAMTS13 function is reduced. Third, while the role of VWF in atherogenesis is debated, arterial thrombosis complicating atherosclerosis appears to be VWF-dependent. The differences in the VWF gene and protein between humans, pigs, and dogs are relatively few but important to consider in the design of VWF-focused experiments. These homologies and differences are reviewed in detail and their implications for research projects are discussed. The current status of porcine and canine VWD are also reviewed as well as their potential role in future studies of VWF-related disorders of hemostasis and thrombosis.
CAREM Project Status
Authors: Magan H. Boado , Delmastro D. F. , Markiewicz M. , Lopasso E. , Diez F. , Giménez M. , Rauschert A. , Halpert S. , Chocrón M. , Dezzutti J. C. , Pirani H. , Balbi C. , Fittipaldi A. , Schlamp M. , Murmis G. M. , Lis H.
Published: February 2011

CAREM is a CNEA (Comisión Nacional de Energía Atómica) project. This project consists of the development, design, and construction of a small nuclear power plant. First, a prototype of an electrical output of about 27 MW, CAREM 25, will be built in order to validate the innovation of the CAREM concept and then developed to commercial version. After several years of development, the CAREM Project reached such a maturity level that the Argentine government decided on the construction of CAREM prototype. Several activities are ongoing with the purpose of obtaining the construction permit for the CAREM prototype.
The MRL/lpr Mouse Strain as a Model for Neuropsychiatric Systemic Lupus Erythematosus
Authors: Gulinello Maria , Putterman Chaim
Published: February 2011

To date, CNS disease and neuropsychiatric symptoms of systemic lupus erythematosus (NP-SLE) have been understudied compared to end-organ failure and peripheral pathology. In this review, we focus on a specific mouse model of lupus and the ways in which this model reflects some of the most common manifestations and potential mechanisms of human NP-SLE. The mouse MRL lymphoproliferation strain (a.k.a. MRL/lpr) spontaneously develops the hallmark serological markers and peripheral pathologies typifying lupus in addition to displaying the cognitive and affective dysfunction characteristic of NP-SLE, which may be among the earliest symptoms of lupus. We suggest that although NP-SLE may share common mechanisms with peripheral organ pathology in lupus, especially in the latter stages of the disease, the immunologically privileged nature of the CNS indicates that early manifestations of particularly mood disorders maybe derived from some unique mechanisms. These include altered cytokine profiles that can activate astrocytes, microglia, and alter neuronal function before dysregulation of the blood-brain barrier and development of clinical autoantibody titres.
Hodgkin Lymphoma at the Paediatric Oncology Unit of Gabriel Touré Teaching Hospital, Bamako, Mali: 5-Year Experience
Authors: Togo B. , Traoré F. , Togo A. P. , Traoré C. B. , Dumke K. , Diawara M. , Diakité A. A. , Sylla M. , Traoré-Dicko F. , Traoré B. , Sidibé T.
Published: February 2011

Introduction. The aim of this retrospective, unicentric study over 5 years is to describe the epidemiologic, pathologic, clinic and therapeutic aspects of children treated for Hodgkin lymphoma in our paediatric oncology unit.Patients and Methods. From January 2005 to December 2009, all children under 18 years of age, with Hodgkin lymphoma were included in this study. The treatment protocol was the GFAOP (Groupe Franco—Africain d'Oncologie Pédiatrique) Hodgkin lymphoma treatment protocol.Results. During the study period, 217 cancer cases were diagnosed in our centre. Of these cases, 7 were Hodgkin Lymphoma (LH) (0.04%). The mean age was 11.7 years. The sex-ratio was 6/1. 4% (5/7) of patients were stage IIB and 28.6% (2/7) stage IIIB of Ann-Arbor classification. There were 3 cases (42.8%) of sclero-nodular subtype, 2 cases (28.6%) of lymphocyte-rich classical HL subtype, 1 case (14.3%) of mixed cellularity and 1 case (14.3%) of lymphocyte depleted subtype. With a median followup of 37 months, 5 patients (71.4%) are alive, and 2 patients (28.6%) died.Conclusion. Broader multicentric studies are needed for more accurate data on this malignancy.
Thermodynamics of Two-Dimensional Electron Gas in a Magnetic Field
Authors: Nizhankovskii V. I.
Published: February 2011

Change of the chemical potential of electrons in a GaAs-AlxGa1−xAs heterojunction was measured in magnetic fields up to 6.5 T at several temperatures from 2.17 to 12.3 K. A thermodynamic equation of state of two-dimensional electron gas well describes the experimental results.
A Probability Approach to the Study on Uncertainty Effects onGamma Index Evaluations in Radiation Therapy
Authors: Cutanda Henríquez Francisco , Vargas Castrillón Silvia
Published: February 2011

Two datasets of points of known spatial positions and an associated absorbed dose value are often compared for quality assurance purposes in External Beam Radiation Therapy (EBRT). Some problems usually arise regarding the pass fail criterion to accept both datasets as close enough for practical purposes. Instances of this kind of comparisons are fluence or dose checks for intensity modulated radiation therapy, modelling of a treatment unit in a treatment planning system, and so forth. The gamma index is a figure of merit that can be obtained from both datasets; it is widely used, as well as other indices, as part of a comparison procedure. However, it is recognized that false negatives may take place (there are acceptable cases where a certain number of points do not pass the test) due in part to
computation and experimental uncertainty. This work utilizes mathematical methods to analyse comparisons, so that uncertainty can be taken into account. Therefore, false rejections due to uncertainty do not take place and there is no need to expand tolerances to take uncertainty into account. The methods provided are based on the rules of uncertainty propagation and help obtain rigorous pass/fail criteria, based on experimental information.
A Prospective Cohort Study on Overweight, Smoking, Alcohol Consumption, and Risk of Barrett's Esophagus
Authors: Steevens Jessie , Schouten Leo J. , Driessen Ann L.C. , Huysentruyt Clément J.R. , Keulemans Yolande C.A. , Goldbohm R. Alexandra , van den Brandt Piet A.
Published: February 2011

Background: Barrett's esophagus (BE) is a precursor lesion of esophageal adenocarcinoma. Besides gastroesophageal reflux, possible risk factors for BE include overweight, cigarette smoking, and alcohol consumption. Our objective was to study these associations by using prospective data.

Methods: The prospective Netherlands Cohort Study, initiated in 1986, consists of 120,852 men and women, aged 55 to 69 years at baseline. At baseline, all subjects completed a questionnaire on dietary habits and lifestyle. After 16.3 years of follow-up, 370 BE cases with specialized intestinal metaplasia and 3,866 subcohort members were available for case–cohort analysis. Cox proportional hazards models were used to calculate incidence rate ratios (RR) and 95% CIs.

Results: Body mass index (BMI) at baseline was associated with risk of BE in women [multivariable adjusted RR per 1 kg/m2, 1.07 (1.03–1.11)] but not in men [RR per 1 kg/m2, 0.99 (0.93–1.05)]. The association in women was not specifically due to abdominal overweight. Former cigarette smokers were at increased risk of BE (RR = 1.33, 95% CI: 1.00–1.77), but current smokers were not. Smoking duration showed a positive association with BE risk (Ptrend = 0.03). For alcohol consumption, the RR per 10 g ethanol/d was 0.95 (0.87–1.03).

Conclusions: Increased BMI was a risk factor for BE in women but not in men. Several aspects of cigarette smoking were positively associated with BE risk. Alcohol consumption was not associated with an increased risk of BE.

Impact: Future research should focus on risk factors both for development and for progression of BE to esophageal adenocarcinoma. Cancer Epidemiol Biomarkers Prev; 20(2); 345–58. ©2010 AACR.
Dietary Phytoestrogens and the Risk of Ovarian Cancer in the Women's Lifestyle and Health Cohort Study
Authors: Hedelin Maria , Löf Marie , Andersson Therese M.-L. , Adlercreutz Herman , Weiderpass Elisabete
Published: February 2011

Background: Dietary intake of phytoestrogens has been inversely associated to hormone-dependent cancers, such as prostate and breast cancers. Few studies have investigated the association between ovarian cancer and intake of phytoestrogens. We evaluated the associations between intake of phytoestrogens (isoflavonoids/lignans/coumestrol) and fiber (vegetable/cereal) and risk of ovarian cancer.

Methods: In 1991–1992 a prospective population-based cohort study among Swedish women was conducted, including 47,140 women with complete dietary questionnaire data. During follow-up until December 2007, 163 women developed invasive (n = 117) and borderline (n = 46) ovarian cancers. The median follow-up time was 16 years and total person year was 747,178. Cox proportional hazards models were conducted to estimate multivariate risk ratios, 95% CI for associations with risk of ovarian cancer.

Results: We found no association between intake of phytoestrogens or fiber and overall ovarian cancer risk. In addition, we found no statistically significant association between intake of specific food items rich in phytoestrogens (berries, nuts, beans/soy, and crisp or whole-grain bread) and ovarian cancer risk overall. Fiber and coumestrol was inversely associated with borderline ovarian cancer, but not with invasive ovarian cancer.

Conclusions: We found no association between intake of phytoestrogens or fiber and overall ovarian cancer risk.

Impact: Phytoestrogens do not play a major etiologic role in ovarian cancer, at least among women in this Swedish cohort with low bean/soy intake. However, our results of a difference in the effect of fiber or coumestrol between invasive and borderline ovarian cancer need to be evaluated in larger studies. Cancer Epidemiol Biomarkers Prev; 20(2); 308–17. ©2011 AACR.
Risk of a Second Breast Cancer Associated with Hormone-Receptor and HER2/neu Status of the First Breast Cancer
Authors: Bessonova Leona , Taylor Thomas H. , Mehta Rita S. , Zell Jason A. , Anton-Culver Hoda
Published: February 2011

Objectives: Hormone-receptor (HR) and HER2/neu-receptor (HER2) status of breast tumors are important indicators for targeted therapies. We examine the association of receptor status and risk for a second breast cancer.

Methods: We analyzed data on 106,331 women in the California Cancer Registry whose first cancer is locoregional invasive breast disease, diagnosed from 1999 through 2005, yielding 1,613 second primary breast cancers. Standardized incidence ratios (SIR) with 95% confidence intervals (CIs) were used to evaluate risk of second tumors, accounting for age at first diagnosis, duration at risk, and race/ethnicity.

Results: Among non-Hispanic whites, HR-positive first tumors signal a reduction in risk for second breast cancers (SIR = 0.83, 95% CI: 0.77–0.89) whereas HR-negative status signals elevated risk (SIR = 1.48, 95% CI: 1.29–1.70). Asian/Pacific Islanders, African Americans, and Hispanics are at elevated risk of second breast cancers regardless of HR status of the first tumor. Hispanics with HR-negative first tumors are at greater risk than those with HR-positive disease (HR−: SIR = 3.76, 95% CI: 2.97–4.71; HR+: SIR = 1.86, 95% CI: 1.56–2.20). HER2 status does not differentiate risk for second tumors in any group examined.

Conclusions: HR status of a first breast cancer is a marker for risk of a second breast cancer. HER2 status does not seem to be a marker of risk for a second breast cancer. Risk differences across race/ethnic groups by HR status suggest heterogeneity of breast cancers across race/ethnicity.

Impact: These data suggest that HR status may be helpful in shaping strategies to reduce risk of a second breast cancer, while HER2 status seems uninformative for this purpose. Cancer Epidemiol Biomarkers Prev; 20(2); 389–96. ©2011 AACR.
Differentiating between Aphasic and Nonaphasic Stroke Patients Using Semantic Verbal Fluency Measures with Administration Time of 30 Seconds
Authors: Kim HyangHee , Kim JungWan , Kim Deog Young , Heo JiHoe
Published: February 2011

Administration time of 1 min for semantic verbal fluency measures can be overly long and therefore bothersome for aphasic patients because they can often retrieve only a few items after a certain period of time. The purpose of this study was to determine whether an administration time of 30 s would be more efficient in differentiating among aphasics, nonaphasic stroke patients, and normal controls. The subjects were 53 stroke patients and 28 normal controls. They had to generate as many animal names as they could within a given time. The number of animal names is gradually diminished in three groups (p < 0.001) in each time frame, that is, during the entire 60 s, the initial 30 s, and the following 30 s. The reaction time (RT) measure indicated that the RT of the aphasic patients was significantly increased compared to those of the other two groups (p < 0.001). The most optimal cutoff scores that differentiated each group are presented. These results suggest that an administration time of 30 s has discriminative validity to differentiate between the two patient groups. This shorter administration time could make the test more efficient by reducing the burden on both examiners and aphasic patients.
Detection of Hidden Structures in Nonstationary Spike Trains
Authors: Takiyama Ken , Okada Masato
Published: February 2011

We propose an algorithm for simultaneously estimating state transitions among neural states and nonstationary firing rates using a switching state-space model (SSSM). This algorithm enables us to detect state transitions on the basis of not only discontinuous changes in mean firing rates but also discontinuous changes in the temporal profiles of firing rates (e.g., temporal correlation). We construct estimation and learning algorithms for a nongaussian SSSM, whose nongaussian property is caused by binary spike events. Local variational methods can transform the binary observation process into a quadratic form. The transformed observation process enables us to construct a variational Bayes algorithm that can determine the number of neural states based on automatic relevance determination. Additionally, our algorithm can estimate model parameters from single-trial data using a priori knowledge about state transitions and firing rates. Synthetic data analysis reveals that our algorithm has higher performance for estimating nonstationary firing rates than previous methods. The analysis also confirms that our algorithm can detect state transitions on the basis of discontinuous changes in temporal correlation, which are transitions that previous hidden Markov models could not detect. We also analyze neural data recorded from the medial temporal area. The statistically detected neural states probably coincide with transient and sustained states that have been detected heuristically. Estimated parameters suggest that our algorithm detects the state transitions on the basis of discontinuous changes in the temporal correlation of firing rates. These results suggest that our algorithm is advantageous in real-data analysis.
Divergence-Based Vector Quantization
Authors: Villmann Thomas , Haase Sven
Published: February 2011

Supervised and unsupervised vector quantization methods for classification and clustering traditionally use dissimilarities, frequently taken as Euclidean distances. In this article, we investigate the applicability of divergences instead, focusing on online learning. We deduce the mathematical fundamentals for its utilization in gradient-based online vector quantization algorithms. It bears on the generalized derivatives of the divergences known as Fréchet derivatives in functional analysis, which reduces in finite-dimensional problems to partial derivatives in a natural way. We demonstrate the application of this methodology for widely applied supervised and unsupervised online vector quantization schemes, including self-organizing maps, neural gas, and learning vector quantization. Additionally, principles for hyperparameter optimization and relevance learning for parameterized divergences in the case of supervised vector quantization are given to achieve improved classification accuracy.
Refinements of Universal Approximation Results for Deep Belief Networks and Restricted Boltzmann Machines
Authors: Montufar Guido , Ay Nihat
Published: February 2011

We improve recently published results about resources of restricted Boltzmann machines (RBM) and deep belief networks (DBN) required to make them universal approximators. We show that any distribution [Formula: see text] on the set [Formula: see text] of binary vectors of length [Formula: see text] can be arbitrarily well approximated by an RBM with [Formula: see text] hidden units, where [Formula: see text] is the minimal number of pairs of binary vectors differing in only one entry such that their union contains the support set of [Formula: see text]. In important cases this number is half the cardinality of the support set of [Formula: see text] (given in Le Roux & Bengio, 2008 ). We construct a DBN with [Formula: see text], hidden layers of width [Formula: see text] that is capable of approximating any distribution on [Formula: see text] arbitrarily well. This confirms a conjecture presented in Le Roux and Bengio ( 2010 ).
Revisiting Tests for Neglected Nonlinearity Using Artificial Neural Networks
Authors: Cho Jin Seo , Ishida Isao , White Halbert
Published: February 2011

Tests for regression neglected nonlinearity based on artificial neural networks (ANNs) have so far been studied by separately analyzing the two ways in which the null of regression linearity can hold. This implies that the asymptotic behavior of general ANN-based tests for neglected nonlinearity is still an open question. Here we analyze a convenient ANN-based quasi-likelihood ratio statistic for testing neglected nonlinearity, paying careful attention to both components of the null. We derive the asymptotic null distribution under each component separately and analyze their interaction. Somewhat remarkably, it turns out that the previously known asymptotic null distribution for the type 1 case still applies, but under somewhat stronger conditions than previously recognized. We present Monte Carlo experiments corroborating our theoretical results and showing that standard methods can yield misleading inference when our new, stronger regularity conditions are violated.
When sounds collide: the effect of anthropogenic noise on a breeding assemblage of frogs in Belize, Central America
Authors: Alloush Menemsha , Scofield Douglas , Marczak Susanne , Jones Robin , Kaiser Kristine , Oliva Mark , Narins Peter M. , Martineau Katherine
Published: February 2011

Many organisms depend on acoustic communication for myriad functions, and have evolved behaviours to minimize effects of naturally occurring acoustic interference. However, as habitats are subject to increased alteration, anthropogenic noise becomes unavoidable, and how animals overcome such interference is not well understood. In most ecosystems, only a subset of frog species is associated with disturbed habitats; the ability of these species to overcome exogenous noise suggests that habitat associations may be related to species' response to noise. We tested the hypothesis that frogs associated with largely undisturbed forest habitat would be less likely to increase call output in response to exogenous noise than would those associated with disturbed or open habitat. While this relationship was not significant, we found a slight trend supporting the hypothesis. We then asked whether anthropogenic noise affects chorus tenure at individual- or at chorus-levels. Male frogs exposed to anthropogenic noise decreased both the number of days present at the chorus and the nightly chorus duration relative to controls. Because females generally join choruses late at night to breed, the effects of noise shown here are likely to substantially decrease frog reproductive success; thus, the acoustic environment may play an important role in shaping population dynamics and in amphibian declines.
Giovanni Gioviano Pontano (1429–1503) on Astrology and Poetic Authority
Authors: Soranzo Matteo
Published: February 2011

L'articolo esamina per quale ragione Giovanni Gioviano Pontano (1429–1503) ha spiegato in termini di causalità astrologica l'origine della sua autorità poetica, con lo scopo di illustrare un elemento di continuità tra Medioevo e Umanesimo. I testi presi in esame sono il poema Urania (scritto nel 1475–1494; stampato nel 1505), il dialogo Actius (scritto nel 1495–1499; stampato nel 1507), il commento al Centiloquio pseudotolemaico (scritto nel 1477; stampato nel 1512) e il trattato De Rebus Coelestibus (scritto nel 1475–1495; stampato nel 1512). Si sostiene che l'approccio astrologico all'autorità poetica di Pontano deriva dalla sua interpretazione del primo aforisma del Centiloquio, e che questa scelta era dettata dal tentativo di mettere in questione la teoria del furor poetico di Marsilio Ficino, le cui opere stavano diventando sempre più diffuse nel contesto della Napoli Aragonese alla fine del Quattrocento.
‘The Business Had to March On’ De Arbeiderspers in Time of War
Authors: Doppenberg Frederike
Published: February 2011

During the Second World War the social-democratic publisher De Arbeiderspers [The Workers’ Press] was transferred into National Socialist hands. The National Socialists wanted to transform the party press of the SDAP, the social democratic party of the Netherlands, into a National Socialist platform. The publisher, however, had a secure circle of socialist customers whom the new management did not want to deter. This article is a study, based on a reconstruction of the list of publications during the period ’40 -’45, of how the National Socialist managers attempted to change the ideological foundation of De Arbeiderspers.
Publishing House Contact and Its Support for Authors in the Second World War
Authors: Kuitert Lisa
Published: February 2011

The name of publishing house Contact is associated with Anne Frank’s diary, of which Contact was the first publisher. In this article, Lisa Kuitert shows how Contact, established in 1933, operated during the Second World War. Although Contact was not a publisher for the resistance, both of its publishing directors, in various ways, supported authors who had been banned from publishing. The means also existed for them to do this because precisely in these five years, the publisher did well financially.
De Bezige Bij Resistance and Bibliography
Authors: Renders Hans
Published: February 2011

The Resistance publishing house De Bezige Bij [The Busy Bee] was financed with money earned with broadside verse and other special publications. This was such a lucrative business that there was even enough money left over to pay for large numbers of Jewish children to go into hiding. During the occupation the company built up a reputation as a left-wing publisher ‐ an image that needed to be maintained after the liberation, even though many of the works published by the post-war Bezige Bij were firmly in a different political camp.
Ernest Satow's Guides to Diplomatic Practice. From the First Edition in 1917 to the Sixth Edition (2009)
Authors: Schwietzke Joachim
Published: February 2011

The Guide to Diplomatic Practice by Ernest Satow is known as a respected work among several generations of diplomats and international lawyers in English speaking countries. The publication of a sixth edition in 2009 permits a comparison with the first edition of 1917 and with some of the subsequent editions.