3,844 research outputs found

    Low frequency creep in CoNiFe films

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    The results of an investigation of domain wall motion excited by slow rise-time, bipolar, hard-axis pulses in vacuum deposited CoNiFe films 1500A to 2000A thick are presented. The results are consistent with those of comparable NiFe films in spite of large differences in film properties. The present low frequency creep data together with previously published results in this and other laboratories can be accounted for by a model which requires that the wall structure change usually associated with low frequency creep be predominately a gyromagnetic process. The correctness of this model is reinforced by the observation that the wall coercive force, the planar wall mobility, and the occurrence of an abrupt wall structure change are the only properties closely correlated to the creep displacement characteristics of a planar wall in low dispersion films

    Practical guidance for applying the ADNEX model from the IOTA group to discriminate between different subtypes of adnexal tumors.

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    All gynecologists are faced with ovarian tumors on a regular basis, and the accurate preoperative diagnosis of these masses is important because appropriate management depends on the type of tumor. Recently, the International Ovarian Tumor Analysis (IOTA) consortium published the Assessment of Different NEoplasias in the adneXa (ADNEX) model, the first risk model that differentiates between benign and four types of malignant ovarian tumors: borderline, stage I cancer, stage II-IV cancer, and secondary metastatic cancer. This approach is novel compared to existing tools that only differentiate between benign and malignant tumors, and therefore questions may arise on how ADNEX can be used in clinical practice. In the present paper, we first provide an in-depth discussion about the predictors used in ADNEX and the ability for risk prediction with different tumor histologies. Furthermore, we formulate suggestions about the selection and interpretation of risk cut-offs for patient stratification and choice of appropriate clinical management. This is illustrated with a few example patients. We cannot propose a generally applicable algorithm with fixed cut-offs, because (as with any risk model) this depends on the specific clinical setting in which the model will be used. Nevertheless, this paper provides a guidance on how the ADNEX model may be adopted into clinical practice

    The Long and Winding Road: Archiving and Re-Using Qualitative Data from 12 Research Projects Spanning 16 Years

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    We describe a pilot project designed to assess the feasibility of re-use across 12 diverse qualitative datasets related to Human Immunodeficiency Virus (HIV) in the UK, from research projects undertaken between 1997 and 2013 – an approach which is chronically underused. First, we consider the sweeping biomedical changes and imperatives relating to HIV in this time frame, offering a rationale for data re-use at this point in the epidemic. We then reflexively situate the processes and procedures we devised for this study with reference to relevant methodological literature. Hammersley’s and Leonelli’s contributions have been particularly instructive through this process, and following their lead, we conclude with further considerations for those undertaking qualitative data re-use, reflecting on the extent to which qualitative data re-use as a practice requires attention to both the given and the constructed aspects of data when assembled as evidence

    Single-Crystal-to-Single-Crystal Transformation of a Novel 2-Fold Interpenetrated Cadmium-Organic Framework with Trimesate and 1,2-Bis(4-pyridyl)ethane into the Thermally Desolvated Form Which Exhibits Liquid and Gas Sorption Properties

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    A novel 2-fold interpenetrated pillared cadmium metal organic framework namely [Cd(HBTC)-BPE](n)center dot nDMF has been synthesized using 1,3,5-benzenetricarboxylic acid and 1,2-bis(4-pyridyl)ethane (BPE). This compound has been desolvated and subjected to various liquids and gases for sorption studies. Structures of the assynthesized (1) desolvated (2) and resolvated in benzene (3) have been determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis IR spectra, and thermogravimetric/differential scanning calorimetry analysis. Single crystal X-ray analysis revealed a 2-fold interpenetrated, three-dimensional (3D) framework which exhibits a 3,5-connected network with the Schlafli symbol of [(6(3))(6(9).8) and hms topology. Compound I exhibits a temperature-induced single-crystal-to-single-crystal (SC SC) transformation upon the release of N,N'-dimethylformamide molecules forming compound 2 (stable up to 300 C). SC SC transformation is also observed when it is immersed in benzene, chloroform, 1,4dioxane, and tetrahydrofuran. The uptake of different solvent molecules was analyzed, and desolvated samples selectively adsorb benzene, chloroform, 1,4-dioxane, and THF molecules over other selected polar solvents. Gas (N-2, CO2, and N2O) sorption experiments were also performed and the structure showed 2.5% N-2 4.5% CO2, and 3.4% N2O absorption by mass at room temperature and moderate gas pressures (similar to 10 bar)

    Generalized Interpolation Material Point Approach to High Melting Explosive with Cavities Under Shock

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    Criterion for contacting is critically important for the Generalized Interpolation Material Point(GIMP) method. We present an improved criterion by adding a switching function. With the method dynamical response of high melting explosive(HMX) with cavities under shock is investigated. The physical model used in the present work is an elastic-to-plastic and thermal-dynamical model with Mie-Gr\"uneissen equation of state. We mainly concern the influence of various parameters, including the impacting velocity vv, cavity size RR, etc, to the dynamical and thermodynamical behaviors of the material. For the colliding of two bodies with a cavity in each, a secondary impacting is observed. Correspondingly, the separation distance DD of the two bodies has a maximum value DmaxD_{\max} in between the initial and second impacts. When the initial impacting velocity vv is not large enough, the cavity collapses in a nearly symmetric fashion, the maximum separation distance DmaxD_{\max} increases with vv. When the initial shock wave is strong enough to collapse the cavity asymmetrically along the shock direction, the variation of DmaxD_{\max} with vv does not show monotonic behavior. Our numerical results show clear indication that the existence of cavities in explosive helps the creation of ``hot spots''.Comment: Figs.2,4,7,11 in JPG format; Accepted for publication in J. Phys. D: Applied Physic

    Multi-level Trainable Segmentation for Measuring Gestational and Yolk Sacs from Ultrasound Images

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    As a non-hazardous and non-invasive approach to medical diagnostic imaging, ultrasound serves as an ideal candidate for tracking and monitoring pregnancy development. One critical assessment during the first trimester of the pregnancy is the size measurements of the Gestation Sac (GS) and the Yolk Sac (YS) from ultrasound images. Such measurements tend to give a strong indication on the viability of the pregnancy. This paper proposes a novel multi-level trainable segmentation method to achieve three objectives in the following order: (1) segmenting and measuring the GS, (2) automatically identifying the stage of pregnancy, and (3) segmenting and measuring the YS. The first level segmentation employs a trainable segmentation technique based on the histogram of oriented gradients to segment the GS and estimate its size. This is then followed by an automatic identification of the pregnancy stage based on histogram analysis of the content of the segmented GS. The second level segmentation is used after that to detect the YS and extract its relevant size measurements. A trained neural network classifier is employed to perform the segmentation at both levels. The effectiveness of the proposed solution has been evaluated by comparing the automatic size measurements of the GS and YS against the ones obtained gynaecologist. Experimental results on 199 ultrasound images demonstrate the effectiveness of the proposal in producing accurate measurements as well as identifying the correct stage of pregnancy

    Three-dimensional structure of an immunoglobulin light-chain dimer with amyloidogenic properties

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    The X-ray structure of an immunoglobulin light-chain dimer isolated from the urine as a 'Bence-Jones protein' from a patient with multiple myeloma and amyloidosis (Sea) was determined at 1.94 Angstrom resolution and refined to R and R-free factors of 0.22 and 0.25, respectively. This 'amyloidogenic' protein crystallized in the orthorhombic P2(1)2(1)2(1) space group with unit-cell parameters a=48.28, b=83.32, c=112.59 Angstrom as determined at 100 K. In the vital organs (heart and kidneys), the equivalent of the urinary protein produced fibrillar amyloid deposits which were fatal to the patient. Compared with the amyloidogenic Mcg light-chain dimer, the Sea protein was highly soluble in aqueous solutions and only crystallized at concentrations approaching 100 mg ml(-1). Both the Sea and Mcg proteins packed into crystals in highly ordered arrangements typical of strongly diffracting crystals of immunoglobulin fragments. Overall similarities and significant differences in the three-dimensional structures and crystalline properties are discussed for the Sea and Mcg Bence-Jones proteins, which together provide a generalized model of abnormalities present in lambda chains, facilitating a better understanding of amyloidosis of light-chain origin (AL)

    The VANDELS survey: Dust attenuation in star-forming galaxies at z=34\mathbf{z=3-4}

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    We present the results of a new study of dust attenuation at redshifts 3<z<43 < z < 4 based on a sample of 236236 star-forming galaxies from the VANDELS spectroscopic survey. Motivated by results from the First Billion Years (FiBY) simulation project, we argue that the intrinsic spectral energy distributions (SEDs) of star-forming galaxies at these redshifts have a self-similar shape across the mass range 8.28.2 \leq log(M/M)10.6(M_{\star}/M_{\odot}) \leq 10.6 probed by our sample. Using FiBY data, we construct a set of intrinsic SED templates which incorporate both detailed star formation and chemical abundance histories, and a variety of stellar population synthesis (SPS) model assumptions. With this set of intrinsic SEDs, we present a novel approach for directly recovering the shape and normalization of the dust attenuation curve. We find, across all of the intrinsic templates considered, that the average attenuation curve for star-forming galaxies at z3.5z\simeq3.5 is similar in shape to the commonly-adopted Calzetti starburst law, with an average total-to-selective attenuation ratio of RV=4.18±0.29R_{V}=4.18\pm0.29. We show that the optical attenuation (AVA_V) versus stellar mass (MM_{\star}) relation predicted using our method is consistent with recent ALMA observations of galaxies at 2<z<32<z<3 in the \emph{Hubble} \emph{Ultra} \emph{Deep} \emph{Field} (HUDF), as well as empirical AVMA_V - M_{\star} relations predicted by a Calzetti-like law. Our results, combined with other literature data, suggest that the AVMA_V - M_{\star} relation does not evolve over the redshift range 0<z<50<z<5, at least for galaxies with log(M/M)9.5(M_{\star}/M_{\odot}) \gtrsim 9.5. Finally, we present tentative evidence which suggests that the attenuation curve may become steeper at log(M/M)9.0(M_{\star}/M_{\odot}) \lesssim 9.0.Comment: 16 pages, 12 figures, accepted for publication in MNRA

    The VANDELS survey: Dust attenuation in star-forming galaxies at z=34\mathbf{z=3-4}

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    We present the results of a new study of dust attenuation at redshifts 3<z<43 < z < 4 based on a sample of 236236 star-forming galaxies from the VANDELS spectroscopic survey. Motivated by results from the First Billion Years (FiBY) simulation project, we argue that the intrinsic spectral energy distributions (SEDs) of star-forming galaxies at these redshifts have a self-similar shape across the mass range 8.28.2 \leq log(M/M)10.6(M_{\star}/M_{\odot}) \leq 10.6 probed by our sample. Using FiBY data, we construct a set of intrinsic SED templates which incorporate both detailed star formation and chemical abundance histories, and a variety of stellar population synthesis (SPS) model assumptions. With this set of intrinsic SEDs, we present a novel approach for directly recovering the shape and normalization of the dust attenuation curve. We find, across all of the intrinsic templates considered, that the average attenuation curve for star-forming galaxies at z3.5z\simeq3.5 is similar in shape to the commonly-adopted Calzetti starburst law, with an average total-to-selective attenuation ratio of RV=4.18±0.29R_{V}=4.18\pm0.29. We show that the optical attenuation (AVA_V) versus stellar mass (MM_{\star}) relation predicted using our method is consistent with recent ALMA observations of galaxies at 2<z<32<z<3 in the \emph{Hubble} \emph{Ultra} \emph{Deep} \emph{Field} (HUDF), as well as empirical AVMA_V - M_{\star} relations predicted by a Calzetti-like law. Our results, combined with other literature data, suggest that the AVMA_V - M_{\star} relation does not evolve over the redshift range 0<z<50<z<5, at least for galaxies with log(M/M)9.5(M_{\star}/M_{\odot}) \gtrsim 9.5. Finally, we present tentative evidence which suggests that the attenuation curve may become steeper at log(M/M)9.0(M_{\star}/M_{\odot}) \lesssim 9.0.Comment: 16 pages, 12 figures, accepted for publication in MNRA

    Modelling environmental drivers of black band disease outbreaks in populations of foliose corals in the genus Montipora

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    Seawater temperature anomalies associated with warming climate have been linked to increases in coral disease outbreaks that have contributed to coral reef declines globally. However, little is known about how seasonal scale variations in environmental factors influence disease dynamics at the level of individual coral colonies. In this study, we applied a multi-state Markov model (MSM) to investigate the dynamics of black band disease (BBD) developing from apparently healthy corals and/or a precursor-stage, termed `cyanobacterial patches' (CP), in relation to seasonal variation in light and seawater temperature at two reef sites around Pelorus Island in the central sector of the Great Barrier Reef. The model predicted that the proportion of colonies transitioning from BBD to Healthy states within three months was appro)dmately 57%, but 5.6% of BBD cases resulted in whole colony mortality. According to our modelling, healthy coral colonies were more susceptible to BBD during summer months when light levels were at their maxima and seawater temperatures were either rising 0r at their maxima. In contrast, CP mostly occurred during spring, when both light and seawater temperatures were rising. This suggests that environmental drivers for healthy coral colonies transitioning into a Cl' state are different from those driving transitions into BBD. Our model predicts that (1) the transition from healthy to CP state is best explained by increasing light, (2) the transition between Healthy to BBD occurs more frequently from early to late summer, (3) 20% of CP infected corals developed BBD, although light and temperature appeared to have limited impact on this state transition, and (4) the number of transitions from Healthy to BBD differed significantly between the two study sites, potentially reflecting differences in localised wave action regimes
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