Significant Curvature Research Articles

CURVATURE OF THE SPECTRAL ENERGY DISTRIBUTIONS OF BLAZARS

The SED of blazars show significant curvature. In this paper, we study the curvature properties for a large sample of Fermi/LAT bright blazars based on quasi-simultaneous SED. Both SEDs of synchrotron and inverse Compton (IC) components are fitted by a log-parabolic law in log_v-log_vfv diagram. The second-degree term of log-parabola measures the curvature of SED. We find a statistically significant correlation between synchrotron peak frequency and its curvature. This result is in agreement with the theoretical prediction, and confirms previous studies, which dealt with single source with various epoch observations or a small sample. If a broken power-law is employed to fit the SED, the difference between the two spectral indexes (alpha2-alpha1) can be considered as a "surrogate" of the SED curvature. We collect spectral parameters of a sample blazars from literature, and find a correlation between the synchrotron peak frequency and the spectral difference. We do not find a significant correlation between the IC peak frequency and its curvature, which may be caused by complicated seed photon field. It is also found that the synchrotron curvatures are on average larger than that of IC curvatures, and there is no correlation between these two parameters. As suggested by previous works in literature, both the log-parabolic law of SED and above correlation can be explained by statistical and/or stochastic particle accelerations. Stochastic particle acceleration predicts a different slope of the correlation from that of statistical one, and our result seems favor stochastic acceleration mechanisms and emission processes. Some of other evidences also seem to support that the electron energy distribution (and/or synchrotron SED) may be log-parabolic, which include SED modeling, particle acceleration simulation, and comparisons between some predictions and empirical relations/correlations.

THE BROAD-BAND X-RAY SPECTRUM OF IC 4329A FROM A JOINTNuSTAR/SUZAKUOBSERVATION

We have obtained a deep, simultaneous observation of the bright, nearby Seyfert galaxy IC 4329A with Suzaku and NuSTAR. Through a detailed spectral analysis, we are able to robustly separate the continuum, absorption and distant reflection components in the spectrum. The absorbing column is found to be modest at $N_H = 6 \times 10^{21}$ cm$^2$, and does not introduce any significant curvature in the Fe K band. We are able to place a strong constraint on the presence of a broadened Fe K{\alpha} line: $E = 6.46^{+0.08}_{-0.07}$ keV rest frame with ${\sigma} = 0.33^{+0.08}_{-0.07}$ keV and $EW = 34^{+8}_{-7}$ eV, though we are not able to constrain any of the parameters of a relativistic reflection model. These results highlight the range in broad Fe K{\alpha} line strengths observed in nearby, bright AGN (roughly an order of magnitude), and imply a corresponding range in the physical properties of the inner accretion disk in these sources. We have also updated our previously reported measurement of the high-energy cutoff of the hard X-ray emission using both observatories rather than just NuSTAR alone: $E_{cut} = 186 \pm 14$ keV. This high-energy cutoff acts as a proxy for the temperature of the coronal electron plasma, enabling us to further separate this parameter from the optical depth of the plasma and to update our results for these parameters as well. We derive $kT = 50^{+6}_{-3}$ keV with ${\tau} = 2.34^{+0.16}_{-0.11}$ using a spherical geometry, $kT = 61 \pm 1$ keV with ${\tau} = 0.68 \pm 0.02$ for a slab geometry, with both having an equivalent goodness-of-fit.

Dynamics of continental accretion

Subduction zones become congested when they try to consume buoyant, exotic crust. The accretionary mountain belts (orogens) that form at these convergent plate margins have been the principal sites of lateral continental growth through Earth's history. Modern examples of accretionary margins are the North American Cordilleras and southwest Pacific subduction zones. The geologic record contains abundant accretionary orogens, such as the Tasmanides, along the eastern margin of the supercontinent Gondwana, and the Altaïdes, which formed on the southern margin of Laurasia. In modern and ancient examples of long-lived accretionary orogens, the overriding plate is subjected to episodes of crustal extension and back-arc basin development, often related to subduction rollback and transient episodes of orogenesis and crustal shortening, coincident with accretion of exotic crust. Here we present three-dimensional dynamic models that show how accretionary margins evolve from the initial collision, through a period of plate margin instability, to re-establishment of a stable convergent margin. The models illustrate how significant curvature of the orogenic system develops, as well as the mechanism for tectonic escape of the back-arc region. The complexity of the morphology and the evolution of the system are caused by lateral rollback of a tightly arcuate trench migrating parallel to the plate boundary and orthogonally to the convergence direction. We find geological and geophysical evidence for this process in the Tasmanides of eastern Australia, and infer that this is a recurrent and global phenomenon.

Upper critical field ofNaFe1−xCoxAs superconductors

The upper critical field of NaFe$_{1-x}$Co$_x$As was measured from $x=0$ to $x=0.08$, with the magnetic field applied parallel ($H_{\rm c2}^\parallel$) and normal ($H_{\rm c2}^\perp$) to the planes. The data were fitted using one-band and two-band models. The orbital and paramagnetic components of the upper critical field were extracted for $H_{\rm c2}^\parallel$, which we find to to be strongly dominated by paramagnetic pair-breaking. In the parent compound the paramagnetic limit is equal to the value expected by BCS theory. However, substitution of Fe by Co leads to an enhancement above the BCS limit by a factor of approximately 1.6. In the over-doped region, we observe a significant convex curvature in $H_{\rm c2}^\perp$ at low temperatures, which we attribute to the two-band nature of the superconductivity and the asymmetry between the two bands. Additionally, we discuss the behavior of critical field anisotropy, coherence length $\xi$, and the penetration depth $\lambda$.

Penile Sonoelastography for the Localization of a Non-Palpable, Non-Sonographically Visualized Lesion in a Patient with Penile Curvature from Peyronie's Disease

Sonoelastography is an emerging ultrasound-based technique that allows characterization of tissue stiffness. The aim of this report is to present a case of significant penile curvature with a non-palpable, non-sonographically visualized plaque that was demonstrable with sonoelastography. A 60-year-old male presented with significant left penile curvature during erections. The penis was evaluated with physical exam followed by B-mode and color Doppler ultrasound. No evidence of plaque was identified with these modalities. Shear wave sonoelastography was pursued to further characterize the patient's Peyronie's disease. An area of increased tissue stiffness that correlated with the site of maximum curvature was identified with shear wave sonoelastography and used to target intralesional injection therapy. Sonoelastography provides an additional way to characterize, localize, and deliver therapy to a lesion in patients with Peyronie's disease and is particularly useful when palpation and B-mode ultrasonography have failed to demonstrate a plaque.

A new correction method serving to eliminate the parabola effect of flatbed scanners used in radiochromic film dosimetry

The purpose of this study is the correction of the lateral scanner artifact, i.e., the effect that, on a large homogeneously exposed EBT3 film, a flatbed scanner measures different optical densities at different positions along the x axis, the axis parallel to the elongated light source. At constant dose, the measured optical density profiles along this axis have a parabolic shape with significant dose dependent curvature. Therefore, the effect is shortly called the parabola effect. The objective of the algorithm developed in this study is to correct for the parabola effect. Any optical density measured at given position x is transformed into the equivalent optical density c at the apex of the parabola and then converted into the corresponding dose via the calibration of c versus dose. For the present study EBT3 films and an Epson 10000XL scanner including transparency unit were used for the analysis of the parabola effect. The films were irradiated with 6 MV photons from an Elekta Synergy accelerator in a RW3 slab phantom. In order to quantify the effect, ten film pieces with doses graded from 0 to 20.9 Gy were sequentially scanned at eight positions along the x axis and at six positions along the z axis (the movement direction of the light source) both for the portrait and landscape film orientations. In order to test the effectiveness of the new correction algorithm, the dose profiles of an open square field and an IMRT plan were measured by EBT3 films and compared with ionization chamber and ionization chamber array measurement. The parabola effect has been numerically studied over the whole measuring field of the Epson 10000XL scanner for doses up to 20.9 Gy and for both film orientations. The presented algorithm transforms any optical density at position x into the equivalent optical density that would be measured at the same dose at the apex of the parabola. This correction method has been validated up to doses of 5.2 Gy all over the scanner bed with 2D dose distributions of an open square photon field and an IMRT distribution. The algorithm presented in this study quantifies and corrects the parabola effect of EBT3 films scanned in commonly used commercial flatbed scanners at doses up to 5.2 Gy. It is easy to implement, and no additional work steps are necessary in daily routine film dosimetry.

Solving a bottleneck in animal models of Peyronie's disease.

Peyronie's disease is characterized by the formation of a fibrous plaque in the tunica albuginea (TA) of the penis. It is a benign condition of unclear etiology, resulting in deformities such as curvature, indentation or shortening. The disease has been shown to be prevalent, especially in older men, and affects quality of life, principally through pain during erection, erectile dysfunction and associated psychological impact. Medical treatment options are limited in number and efficacy for Peyronie's disease; leaving surgery as the only efficacious options for most patients. Development of novel therapeutic approaches is hampered by lack of reproducible, inexpensive and consistent animal models which mirror the clinical aspects of the disease, most importantly curvature formation and ossification. Previous models used injections of transforming growth factor-beta1 or fibrin2 and surgical trauma to TA;3 however, neither significant curvature nor ossification was achieved. Repeated administration of transforming growth factor-beta is required to achieve significant curvature.4 Tsk genetic mouse has achieved curvature and cartilage formation,5 but is an expensive model and the fibrosis is not limited to TA. In the manuscript ‘Tunica albuginea allograft: a new model of LaPeyronie's disease with penile curvature and subtunical ossification’ published on Asian Journal of Andrology, Ferretti et al.6 demonstrated that allograft TA transplantation in rats can achieve both significant curvature and some signs of ossification. Importantly the authors performed experiments in a temporal fashion, investigating various parameters at different time points (1, 3, 7 and 12 weeks) after allografting. By doing so, they were able to show that TA allografting was able to cause curvature and elastic fiber loss as early as 1 week after the operation, while erectile dysfunction was observed only at 12th week. Curvature and elastic fiber loss was stable for 12 weeks. These results may suggest that the curvature can be simply due to disruption of normal morphology of the TA during tissue resection and grafting, not necessarily due to inflammatory processes triggered by the allograft. However, the authors’ observation that ‘…when the grafted tunica was rejected from the corpus cavernosum, a new tunica appeared underneath the allograft. This new tunica, however, was rebuilt in an irregular fashion with disappearance of the two original layers organization (external longitudinal and internal circular). Cartilage-like areas were also seen in 30% of the cases with lacunae chambers and matrix material which fills space between lacunae’ is extremely important as it suggests that ossification may be triggered in the newly formed TA in an inflammatory microenvironment. Obviously, further temporal analysis of this phenomenon (i.e., longer than 12 weeks) will be essential to understand how inflammation can lead to ossification in a disorganized TA tissue. The perfect animal model of Peyronie's disease may not be here yet, but Ferretti et al. should be commended for their detailed temporal analysis and their very important observation which may lead to further basic science research as well as further development of this model. COMPETING INTERESTS The authors declare that they have no competing interests.

Using transient and steady-state SEA to assess potential errors in the measurement of structure-borne sound power input from machinery on coupled reception plates

Isolated reception plates provide an engineering approach to quantify the structure-borne sound power input from machinery through the measurement of the spatial-average velocity level and structural reverberation times. For applications in building acoustics there are practical and economic reasons to consider using coupled reception plates formed by solid heavyweight walls or floors that are structurally coupled to other building elements. This paper uses transient and steady-state statistical energy analysis to investigate how the errors depend upon the building structure to which the coupled reception plate is connected. It is shown that the problem is twofold. Firstly, in the low- and mid-frequency ranges, the steady-state velocity level on the coupled reception plate is increased by energy returning from other coupled plates. Secondly, the structural decays on the coupled reception plate have significant curvature due to returning energy; hence short evaluation ranges are needed to minimise the error when determining the total loss factor. This leads to a problematic situation where the coupled reception plate appears to give the correct answer due to the error in the energy cancelling out the error in the total loss factor. The latter error can be minimised using short evaluation ranges for the structural reverberation time.

Influence of firing time and framework thickness on veneered Y-TZP discs curvature

ObjectivesThe objective of the present work was to study the curvature of very thinly, veneered Y-TZP discs of different framework thicknesses submitted to different firing times. MethodsFifteen 20-mm-wide Y-TZP discs were produced in three different thicknesses: 0.75, 1, 1.5mm. One disc from each group was left unveneered while the others were layered with a 0.1mm veneering ceramic layer. All discs underwent five firing cycles for a total cumulative firing time of 30min, 1, 2, 5 and 10h at 900°C. The curvature profile was measured using a profilometer after the veneering process and after each firing cycle respectively. A fitted curve was then used to estimate the, curvature radius. The coefficient of thermal expansion (CTE) measurements were taken on veneering, ceramic and Y-TZP beam samples that underwent the same firing schedule. Those data were used to calculate the curvature generated by CTE variations over firing time. ResultsAll bilayered samples exhibited a curvature that increased over firing time inversely to framework thickness. However non-veneered samples did not exhibit any curvature modification. SignificanceThe results of the present study reveal that even a very thin veneer layer (0.1mm) can induce a significant curvature of Y-TZP discs. The dilatometric results showed that Tg and CTE, variations are not sufficient to explain this curvature. A chemical-induced zirconia volume, augmentation located at the framework sub-surface near the interface could explain the sample, curvature and its increase with firing time.

First Report of Pepper Fruit Rot Caused by Fusarium concentricum in China.

Pepper (Capsicum annuum L.) is an important vegetable crop worldwide. Some Fusarium species can cause pepper fruit rot, leading to significant yield losses of pepper production and, for some Fusarium species, potential risk of mycotoxin contamination. A total of 106 diseased pepper fruit samples were collected from various pepper cultivars from seven provinces (Gansu, Hainan, Heilongjiang, Hunan, Shandong, Shanghai, and Zhejiang) in China during the 2012 growing season, where pepper production occurs on approximately 25,000 ha. Pepper fruit rot symptom incidence ranged from 5 to 20% in individual fields. Symptomatic fruit tissue was surface-sterilized in 0.1% HgCl2 for 1 min, dipped in 70% ethanol for 30 s, then rinsed in sterilized distilled water three times, dried, and plated in 90 mm diameter petri dishes containing potato dextrose agar (PDA). After incubation for 5 days at 28°C in the dark, putative Fusarium colonies were purified by single-sporing. Forty-three Fusarium strains were isolated and identified to species as described previously (1,2). Morphological characteristics of one strain were identical to those of F. concentricum. Aerial mycelium was reddish-white with an average growth rate of 4.2 to 4.3 mm/day at 25°C in the dark on PDA. Pigments in the agar were formed in alternating red and orange concentric rings. Microconidia were 0- to 1-septate, mostly 0-septate, and oval, obovoid to allantoid. Macroconidia were relatively slender with no significant curvature, 3- to 5-septate, with a beaked apical cell and a foot-shaped basal cell. To confirm the species identity, the partial TEF gene sequence (646 bp) was amplified and sequenced (GenBank Accession No. KC816735). A BLASTn search with TEF gene sequences in NCBI and the Fusarium ID databases revealed 99.7 and 100% sequence identity, respectively, to known TEF sequences of F. concentricum. Thus, both morphological and molecular criteria supported identification of the strain as F. concentricum. This strain was deposited as Accession MUCL 54697 (http://bccm.belspo.be/about/mucl.php). Pathogenicity of the strain was confirmed by inoculating 10 wounded, mature pepper fruits that had been harvested 70 days after planting the cultivar Zhongjiao-5 with a conidial suspension (1 × 106 spores/ml), as described previously (3). A control treatment consisted of inoculating 10 pepper fruits of the same cultivar with sterilized distilled water. The fruit were incubated at 25°C in a moist chamber, and the experiment was repeated independently in triplicate. Initially, green to dark brown lesions were observed on the outer surface of inoculated fruit. Typical soft-rot symptoms and lesions were observed on the inner wall when the fruit were cut open 10 days post-inoculation. Some infected seeds in the fruits were grayish-black and covered by mycelium, similar to the original fruit symptoms observed at the sampling sites. The control fruit remained healthy after 10 days of incubation. The same fungus was isolated from the inoculated infected fruit using the method described above, but no fungal growth was observed from the control fruit. To our knowledge, this is the first report of F. concentricum causing a pepper fruit rot.

Urethral advancement in hypospadias with a distal division of the corpus spongiosum: Outcome in 158 cases

ObjectiveOutcome of urethral mobilization and advancement (Koff procedure) in hypospadias with a distal division of the corpus spongiosum and redo cases with distal urethral failure. Materials and methodsFrom January 1999 to November 2012, 158 children with a distal hypospadias (115 primary cases and 43 redo cases) underwent surgical repair using the Koff technique with a median age at surgery of 21 months (range, 12–217 months). ResultsMean follow-up was 19 months (median, 14 months). Thirty patients (19%) presented with a complication (13.9% in primary cases and 32.5% in redo surgery) mostly at the beginning of our experience. Meatal stenosis was the most common one (3.5% in primary case, 6% overall). Ventral curvature (>10°), which is considered as a possible long-term iatrogenic complication of the Koff procedure, was not found in patients with fully grown penis except in one redo patient who had, retrospectively, an inadequate indication for this type of repair. Of 158 patients, 33 reached the age of puberty (>14 years old) with a mean follow-up of 34 months, only one presented with a significant ventral curvature. ConclusionUrethral mobilization and advancement is a reasonable alternative for anterior hypospadias and distal fistula repair in selected cases. It has two major advantages compared to other techniques: it avoids any urethroplasty with non-urethral tissue and eliminates dysplastic tissues located beyond the division of the corpus spongiosum, which may not grow at the same pace as the rest of the penis. Significant iatrogenic curvature in fully grown penis is not supported by this series.

A new formulation to study in-plane vibration of curved carbon nanotubes conveying viscous fluid

Shortly after the discovery of carbon nanotubes (CNTs), the existence of differently shaped CNTs other than straight ones was predicted theoretically. Recently photomicrographic images show that CNTs are not actually straight but have significant curvature. This aspect was mostly neglected in previous studies on CNTs’ dynamic behavior. In this paper a new formulation governing the in-plane motion of curved CNTs conveying viscous fluid is derived to study their in-plane free vibration. In this formulation the fluid is considered to be viscous and the size effects of nanotubes are also taken into consideration through nonlocal elasticity theory. In this study CNT is modeled as a hollow cylindrical tube and the moving fluid inside is modeled as a plug flow characterized by its mass density, viscosity, and mean velocity. The new formulation is used to study the vibration and instability characteristics of curved and wavy carbon nanotubes. Using finite element analysis it is shown that the nonlocal parameter, the viscosity of fluid, and also the curvature have considerable effects on the natural frequency and critical flow velocity of carbon nanotubes. Also the effect of boundary conditions on natural frequency and critical flow velocity is studied.

Total scattering analysis of cation coordination and vacancy pair distribution in Yb substituted δ-Bi2O3

Reverse Monte Carlo (RMC) modelling of neutron total scattering data, combined with conventional Rietveld analysis of x-ray and neutron data, has been used to describe the cation coordination environments and vacancy pair distribution in the oxide ion conducting electrolyte Bi3YbO6. The thermal variation of the cubic fluorite unit cell volume, monitored by variable temperature x-ray and neutron experiments, reveals significant curvature, which is explained by changes in the oxide ion distribution. There is a significant increase in tetrahedral oxide ion vacancy concentration relative to δ-Bi2O3, due to the creation of Frenkel defects associated with the Yb3+ cation. The tetrahedral oxide ion vacancy concentration increases from room temperature to 800 ° C, but little change is observed in the vacancy pair distribution with temperature. The vacancy pair distributions at both temperatures are consistent with a favouring of 〈100〉 vacancy pairs.

Solar energetic particle drifts in the Parker spiral

Drifts in the Parker spiral interplanetary magnetic field are known to be an important component in the propagation of galactic cosmic rays, while they are thought to be negligible for solar energetic particles (SEPs). As a result, they have so far been ignored in SEP propagation modeling and data analysis. We examine drift velocities in the Parker spiral within single particle first‐order adiabatic theory, in a local coordinate system with an axis parallel to the magnetic field. We show that, in the presence of scattering in interplanetary space, protons at the high end of the SEP energy range experience significant gradient and curvature drift. In the scatter‐free case, drift due to magnetic field curvature is present. The magnitude of drift velocity increases by more than an order of magnitude at high heliographic latitudes compared to near the ecliptic; it has a strong dependence on radial distance r from the Sun, reaching a maximum at r∼1 AU at low heliolatitudes and r∼10 AU at high heliolatitudes. Due to the mass over charge dependence of drift velocities, the effect of drift for partially ionized SEP heavy ions is stronger than for protons. Drift is therefore likely to be a considerable source of cross‐field transport for high‐energy SEPs.

Hydrophobicity and geometry: Water at curved graphitic-like surfaces and within model pores in self-assembled monolayers

In this work we perform molecular dynamics simulations of water in contact with simple model hydrophobic surfaces and pores in order to test the role of local geometry on hydrophobicity. Specifically, we study different quantities like orientational ordering, density fluctuations and water residence times (autocorrelation functions) around graphene sheets, at the exterior of single-walled carbon nanotubes, at alkane-like self-assembled monolayers (SAMs) and at pores of different sizes carved in such SAMs. We show that in the case of the convex graphitic-like surfaces, the cuvature does not affect the local hydrophobicity. However, significant curvature dependence will be made evident for the concave surfaces of the pores carved in the SAMs. The geometrically induced dehydration that occurs as the pore size reaches the subnanometric regime might be operative in realistic settings like protein binding sites which require water remotion upon ligand binding.

DNA phosphate crowding correlates with protein cationic side chain density and helical curvature in protein/DNA crystal structures

Sequence-specific binding of proteins to their DNA targets involves a complex spectrum of processes that often induce DNA conformational variation in the bound complex. The forces imposed by protein binding that cause the helical deformations are intimately interrelated and difficult to parse or rank in importance. To investigate the role of electrostatics in helical deformation, we quantified the relationship between protein cationic residue density (Cpc) and DNA phosphate crowding (Cpp). The correlation between Cpc and Cpp was then calculated for a subset of 58 high resolution protein–DNA crystal structures. Those structures containing strong Cpc/Cpp correlation (>±0.25) were likely to contain DNA helical curvature. Further, the correlation factor sign predicted the direction of helical curvature with positive (16 structures) and negative (seven structures) correlation containing concave (DNA curved toward protein) and convex (DNA curved away from protein) curvature, respectively. Protein–DNA complexes without significant Cpc/Cpp (36 structures) correlation (-0.25<0<0.25) tended to contain DNA without significant curvature. Interestingly, concave and convex complexes also include more arginine and lysine phosphate contacts, respectively, whereas linear complexes included essentially equivalent numbers of Lys/Arg phosphate contacts. Together, these findings suggest an important role for electrostatic interactions in protein–DNA complexes involving helical curvature.

Experimental design optimization for electrochemical removal of gentamicin: toxicity evaluation and degradation pathway

Electrochemical degradation of gentamicin was achieved using a laboratory scale electrochemical reactor by optimizing pH, current density and treatment time. A two step statistical optimization was performed as per factorial design and center composite design (CCD). A Pareto chart was used for selecting statistically significant effects and an analysis of variance (ANOVA) table indicated significant curvature. Thus adding additional experimental runs improved the model fitting through a second order model. Maximum degradation was predicted at a pH of 6.7, 70 A m(-2) and 45 min. The experimental data fitted well through a reduced quadratic model with R(2) equal to 0.945. The toxicity of degradation products as determined by disc diffusion assay employing Pseudomonas aeruginosa strain was found to be reduced by 55%. The degradation pathway of gentamicin was studied using mass spectral (MS) analysis. Pure gentamicin showed a molecular ion peak at m/z 478 ([M + 1](+)), and after addition of NaCl as electrolyte, the mass peak was observed at m/z 523. After 15 min of electrochemical treatment, a new peak appeared at m/z 316 due to the loss of one pyran moiety. After 45 min of electrochemical treatment, another peak appeared at m/z of 478 due to loss of two Na(+) from gentamicin.

Les malformations congénitales du pénis

Congenital abnormalities of the penis are usually diagnosed at birth and pose aesthetic and functional problems sometimes requiring surgical management. A literature review was conducted on Medline considering the articles listed until January 2012. Hypospadias is the most common malformation (1 in 250 boys. Familial forms: 7%). The causes remain hypothetical but the doubling of the incidence in 30 years could be linked to fetal exposure to endocrine disruptors "estrogen-like" used in the food industry in particular. Surgical treatment is usually intended to improve the aesthetic appearance but sometimes, in case of significant curvature or posterior meatus, necessary for normal sexual life and fertility. Other malformations (epispades, buried penis, transpositions, twists and preputial abnormalities) as well as management for functional or aesthetic consequences of these malformations in adulthood require complex surgical care in a specialized environment. The improvement of surgical techniques and pediatric anesthesia allows an early and effective specialized surgical approach of penile malformations. Management of sequelae in adulthood must be discussed and requires experience of surgical techniques on pediatric and adult penis.

Upper critical magnetic field of KxFe2−ySe2and Eu0.5K0.5Fe2As2single crystals

The $H\ensuremath{-}T$ phase diagrams of single crystalline electron-doped ${\text{K}}_{0.83}{\text{Fe}}_{1.83}{\text{Se}}_{2}$ (KFS1), ${\text{K}}_{0.8}{\text{Fe}}_{2}{\text{Se}}_{2}$ (KFS2) and hole-doped ${\text{Eu}}_{0.5}{\text{K}}_{0.5}{\text{Fe}}_{2}{\text{As}}_{2}$ (EKFA) have been deduced from tunnel diode oscillator-based contactless measurements in pulsed magnetic fields up to $57\phantom{\rule{4.pt}{0ex}}\text{T}$ for the interplane ($H\ensuremath{\parallel}c$) and in-plane ($H\ensuremath{\parallel}ab$) directions. The temperature dependence of the upper critical magnetic field ${H}_{c2}(T)$ relevant to EFKA is accounted for by Pauli model including an anisotropic Pauli paramagnetic contribution (${\ensuremath{\mu}}_{B}{H}_{p}=114\phantom{\rule{4.pt}{0ex}}\text{T}$ for $H\ensuremath{\parallel}ab$ and $86\phantom{\rule{4.pt}{0ex}}\text{T}$ for $H\ensuremath{\parallel}c$). This is also the case of KFS1 and KFS2 for $H\ensuremath{\parallel}ab$ whereas a significant upward curvature, accounted for by a two-gap model, is observed for $H\ensuremath{\parallel}c$. Despite the presence of antiferromagnetic lattice order within the superconducting state of the studied compounds, no influence of magnetic ordering on the temperature dependence of ${H}_{c2}(T)$ is observed.

On the application of Weibull analysis to experimentally determined single fibre strength distributions

The application of Weibull theory to the analysis of experimental data obtained from the tensile testing of reinforcement fibres is widespread in composites research and development. One basic assumption implicit in the use of Weibull analysis is that all values of fibre strength described by any set of unimodal or multimodal Weibull parameters are accessible experimentally. However, this is not the case, as a minimum level of fibre strength is necessary in order to be able to isolate, prepare and test any fibre. In this paper the consequences of this experimental limitation are explored in terms of the commonly applied Weibull graphical analysis method. It is demonstrated that this can result in significant curvature in a standard Weibull plot at the low strength end of the data. Furthermore, at low sampling numbers this effect can be misinterpreted as evidence of multiple defect populations. The phenomenon significantly affects the values of the Weibull parameters obtained from the graphical analysis and also from the average strength versus gauge length analysis. The presence of this lower limit presents a serious challenge to those wishing to support conclusions on the physics and mechanics of fibre fracture from Weibull analysis of single fibre tensile data.