Fusion PET-CT imaging of neurolymphomatosis

In a patient suffering from peripheral neuropathy due to neurolymphomatosis, fused PET-CT imaging, performed on a novel in-line PET-CT system, showed multiple small nodular lesions extending along the peripheral nerves corresponding to an early relapse of a transformed B-cell non-Hodgkin's lymphom

Rituximab-EPOCH, an effective salvage therapy for relapsed, refractory or transformed B-cell lymphomas: results of a phase II study

Background: Relapsed or refractory diffuse large B-cell and mantle-cell lymphoma have a poor prognosis. The EPOCH regimen and rituximab monotherapy have demonstrated activity as salvage therapies. Because of their non-overlapping toxicity, we evaluated their combination as salvage therapy in a phase II study. Patients and methods: Patients with relapsed or refractory CD20-positive large B-cell and mantle-cell lymphoma were offered treatment with rituximab 375 mg/m2 intravenously (i.v.) on day 1, doxorubicin 15 mg/m2 as a continuous i.v. infusion on days 2-4, etoposide 65 mg/m2 as a continuous i.v. infusion on days 2-4, vincristine 0.5 mg as a continuous i.v. infusion on days 2-4, cyclophosphamide 750 mg/m2 i.v. on day 5 and prednisone 60 mg/m2 orally on days 1-14. Results: Fifty patients, with a median age of 56 years (range 23-72), entered the study. Twenty-five had primary diffuse large B-cell lymphoma, 18 transformed large B-cell lymphoma and seven mantle-cell lymphoma. The median number of prior chemotherapy regimens was 1.7 (range one to four). The median number of treatment cycles was four (range one to six). Possible treatment-related death occurred in two patients. Objective responses were obtained in 68% of patients (28% complete responses, 40% partial responses). Nineteen patients received consolidating high-dose chemotherapy with autologous stem-cell transplantation. The median follow-up was 33 months. Three patients developed a secondary myelodysplastic syndrome. The median overall survival was 17.9 months; the projected overall survival at 1, 2 and 3 years was 66, 42 and 35%, respectively. The median event-free survival was 11.8 months; the projected event-free survival at 1, 2 and 3 years was 50, 30 and 26%, respectively. Conclusion: The rituximab-EPOCH regimen is effective and well tolerated, even in extensively pretreated patients with relapsed or refractory large B-cell lymphoma and mantle-cell lymphom

Chemical diversity of gas in distant galaxies: The metal and dust enrichment and variations within absorbing galaxies

The chemical composition of gas in galaxies can be measured in detail from absorption spectroscopy. By studying gas in galaxies in this way, it is possible to investigate the small and faint galaxies, which are the most numerous in the universe. In particular, the chemical distribution of gas in absorbing systems gives us insight into cycles of gas in and around galaxies. Here we study chemical enrichment within 64 Damped Lyman-alpha Absorption (DLA) systems between $1.7 < z < 4.2$. We use high-resolution spectra from VLT/UVES to infer dust depletion from relative abundances of several metals. We perform a component-by-component analysis within DLAs, and characterise variations in their chemical enrichment. Unlike hydrogen, the metal columns can be characterised for individual components. We use them to derive the dust depletion ([Zn/Fe]fit), as an indicator for chemical enrichment. We find that some DLAs are chemically diverse within themselves, with [Zn/Fe]fit ranging up to 0.62 dex within a single system. This suggests that absorbing gas within these galaxies is chemically diverse. Although we do not find a clear trend of decreasing dust depletion with redshift, we do see that the most chemically enriched systems are at lower redshifts. We also observe evidence for dust-poor components at all redshifts, which may be due to the accretion of pristine gas onto galaxies. We combine the chemical and kinematic properties of the individual gas components and observe potential signatures of infalling gas, with low depletion at velocities below $\sim$100km/s, and outflows, with high depletion and velocities of $\sim$600km/s. We find over-abundances of alpha-elements (an enhancement of $\sim$0.3dex) and under-abundances of Mn in several components, which is likely a signature of core-collapse SNe nucleosythesis in the ISM. We observe these effects mostly at lower levels of chemical enrichment.Comment: 56 pages, 99 figures, Accepted for publication in A&A, Abstract abridged for arXi

Why are aggregate equity payouts pro-cyclical?

We use two general equilibrium models to explain why changes in the external economic environment result in pro-cyclical aggregate dividend payout behavior. Both models that we consider endogenize low elasticity of investment. The first model incorporates capital adjustment costs, while the second one assumes that risk-averse managers maximize their own objective function rather than shareholder wealth. We show that, while both models generate pro-cyclical aggregate dividends, a feature consistent with the observed business-cycle pattern of payouts from well-diversified portfolios, the second model provides a more likely explanation for this effect. Our findings emphasize the importance of incorporating agency conflicts when considering the relationship between the external economic environment and the financial behavior of businesses

Quantifying Collaboration Quality in Face-to-Face Classroom Settings Using MMLA

Producción CientíficaThe estimation of collaboration quality using manual observation and coding is a tedious and difficult task. Researchers have proposed the automation of this process by estimation into few categories (e.g., high vs. low collaboration). However, such categorical estimation lacks in depth and actionability, which can be critical for practitioners. We present a case study that evaluates the feasibility of quantifying collaboration quality and its multiple sub-dimensions (e.g., collaboration flow) in an authentic classroom setting. We collected multimodal data (audio and logs) from two groups collaborating face-to-face and in a collaborative writing task. The paper describes our exploration of different machine learning models and compares their performance with that of human coders, in the task of estimating collaboration quality along a continuum. Our results show that it is feasible to quantitatively estimate collaboration quality and its sub-dimensions, even from simple features of audio and log data, using machine learning. These findings open possibilities for in-depth automated quantification of collaboration quality, and the use of more advanced features and algorithms to get their performance closer to that of human coders.European Union via the European Regional Development Fund and in the context of CEITER and Next-Lab (Horizon 2020 Research and Innovation Programme, grant agreements no. 669074 and 731685)Junta de Castilla y León (Project VA257P18)Ministerio de Ciencia, Innovación y Universidades (Project TIN2017-85179-C3-2-R

Dust depletion of of metals from local to distant galaxies II: Cosmic dust-to-metal ratio and dust composition

The evolution of the cosmic dust content and the cycle between metals and dust in the interstellar medium (ISM) play a fundamental role in galaxy evolution. The chemical enrichment of the Universe can be traced through the evolution of the dust-to-metals ratio (DTM) and the dust-to-gas ratio (DTG) with metallicity. We use a novel method to determine mass estimates of the DTM, DTG and dust composition based on our previous measurements of the depletion of metals in different environments (the Milky Way, the Magellanic Clouds, and damped Lyman-$\alpha$ absorbers, DLAs, toward quasars and towards gamma-ray bursts, GRBs), which were calculated from the relative abundances of metals in the ISM through absorption-line spectroscopy column densities observed mainly from VLT/UVES and X-shooter, and HST/STIS. We derive the dust extinction from the estimated dust depletion ($A_{V, \rm depl}$) and compare with the $A_{V}$ from extinction. We find that the DTM and DTG ratios increase with metallicity and with the dust tracer [Zn/Fe]. This suggests that grain growth in the ISM is a dominant process of dust production. The increasing trend of the DTM and DTG with metallicity is in good agreement with a dust production and evolution model. Our data suggest that the stellar dust yield is much lower than the metal yield and thus that the overall amount of dust in the warm neutral medium that is produced by stars is much lower. We find that $A_{V,\rm depl}$ is overall lower than $A_{V, \rm ext}$ for the Milky Way and a few Magellanic Clouds lines of sight, a discrepancy that is likely related to the presence of carbonaceous dust. We show that the main elements that contribute to the dust composition are, O, Fe, Si, Mg, C, S, Ni and Al for all the environments. Abundances at low dust regimes suggest the presence of pyroxene and metallic iron in dust.Comment: Accepted for publication in A&A. Abstract abridge

Analytic frameworks for assessing dialogic argumentation in online learning environments

Over the last decade, researchers have developed sophisticated online learning environments to support students engaging in argumentation. This review first considers the range of functionalities incorporated within these online environments. The review then presents five categories of analytic frameworks focusing on (1) formal argumentation structure, (2) normative quality, (3) nature and function of contributions within the dialog, (4) epistemic nature of reasoning, and (5) patterns and trajectories of participant interaction. Example analytic frameworks from each category are presented in detail rich enough to illustrate their nature and structure. This rich detail is intended to facilitate researchers’ identification of possible frameworks to draw upon in developing or adopting analytic methods for their own work. Each framework is applied to a shared segment of student dialog to facilitate this illustration and comparison process. Synthetic discussions of each category consider the frameworks in light of the underlying theoretical perspectives on argumentation, pedagogical goals, and online environmental structures. Ultimately the review underscores the diversity of perspectives represented in this research, the importance of clearly specifying theoretical and environmental commitments throughout the process of developing or adopting an analytic framework, and the role of analytic frameworks in the future development of online learning environments for argumentation

Towards virtual histology with X-ray grating interferometry

Breast cancer is the most common type of cancer worldwide. Diagnosing breast cancer relies on clinical examination, imaging and biopsy. A core-needle biopsy enables a morphological and biochemical characterization of the cancer and is considered the gold standard for breast cancer diagnosis. A histopathological examination uses high-resolution microscopes with outstanding contrast in the 2D plane, but the spatial resolution in the third, Z-direction, is reduced. In the present paper, we propose two high-resolution table-top systems for phase-contrast X-ray tomography of soft-tissue samples. The first system implements a classical Talbot-Lau interferometer and allows to perform ex-vivo imaging of human breast samples with a voxel size of 5.57 μm. The second system with a comparable voxel size relies on a Sigray MAAST X-ray source with structured anode. For the first time, we demonstrate the applicability of the latter to perform X-ray imaging of human breast specimens with ductal carcinoma in-situ. We assessed image quality of both setups and compared it to histology. We showed that both setups made it possible to target internal features of breast specimens with better resolution and contrast than previously achieved, demonstrating that grating-based phase-contrast X-ray CT could be a complementary tool for clinical histopathology

Short-term memory for emotional faces in dysphoria

The study aimed to determine if the memory bias for negative faces previously demonstrated in depression and dysphoria generalises from long- to short-term memory. A total of 29 dysphoric (DP) and22 non-dysphoric (ND) participants were presented with a series of faces and asked to identify the emotion portrayed (happiness, sadness, anger, or neutral affect). Following a delay, four faces were presented (the original plus three distractors) and participants were asked to identify the target face. Half of the trials assessed memory for facial emotion, and the remaining trials examined memory for facial identity. At encoding, no group differences were apparent. At memory testing, relative to ND participants, DP participants exhibited impaired memory for all types of facial emotion and for facial identity when the faces featured happiness, anger, or neutral affect, but not sadness. DP participants exhibited impaired identity memory for happy faces relative to angry, sad, and neutral, whereas ND participants exhibited enhanced facial identity memory when faces were angry. In general, memory for faces was not related to performance at encoding. However, in DP participants only, memory for sad faces was related to sadness recognition at encoding. The results suggest that the negative memory bias for faces in dysphoria does not generalise from long- to short-term memory