Reproducibility of experiments in recommender systems evaluation

© IFIP International Federation for Information Processing 2018 Published by Springer International Publishing AG 2018. All Rights Reserved. Recommender systems evaluation is usually based on predictive accuracy metrics with better scores meaning recommendations of higher quality. However, the comparison of results is becoming increasingly difficult, since there are different recommendation frameworks and different settings in the design and implementation of the experiments. Furthermore, there might be minor differences on algorithm implementation among the different frameworks. In this paper, we compare well known recommendation algorithms, using the same dataset, metrics and overall settings, the results of which point to result differences across frameworks with the exact same settings. Hence, we propose the use of standards that should be followed as guidelines to ensure the replication of experiments and the reproducibility of the results

Cold exposure and adipose nitric oxide and mast cells: influence on aorta contractility

Both nitric oxide (NO) and mast cells play important roles in adipose and vascular tissue biology. Chronic cold stress decreases the sensitivity of vascular smooth muscle to various contractile agents including norepinephrine (NE). In our previous cold exposure study we found that the contractile response of isolated rat aortas to NE was significantly reduced, and the number of rat aortic adventitial mast cells decreased. Histologically and functionally, white and brown adipose tissue (WAT and BAT) can be distinguished. Beyond its significance in energy store/release and heat production, adipose tissue secretes multiple signaling molecules that have endocrine and paracrine role in the regulation of vascular functions. The aims of the present study were to examine chronic cold exposure-induced alterations in (i) the concentration of NO released from selected regions of WAT and BAT in female and male rats, (ii) the histochemistry of white and brown adipose mast cells, and (iii) whether adipose-derived NO affects the contraction of isolated rat aorta to NE. Twelve females and 12 males Spraque-Dawley rats (150-200 g body weight) were used. The rats were exposed to a cold/freely moving stress for 2 hours each day for 5 consecutive days. At the end of cold exposure, the rats were sacrificed, and samples of thoracic aorta with associated periadventitial adipose tissue (tunica adiposa) were obtained. WAT and BAT were isolated from subcutaneous abdominal and interscapular areas, respectively. The concentration of NO was measured by capillary electrophoresis and mast cells were evaluated histochemically. The response of aorta smooth muscles to NE was recorded in the isolated organ bath. To determine whether adipose-derived NO affects aorta contraction to NE, cumulative dose response curves to NE (10-8-10-3 M) were obtained with or without isolated WAT/BAT suspended in the organ bath medium. In control animals, a gender-related significant difference in NO production in both WAT and BAT was found, NO levels being significantly higher in female than male rats. Data from the contractile response of isolated aorta to NE suggest that receptor affinity to NE is significantly different between female and male controls. Presence of BAT and WAT (isolated from cold-exposure animals) in the bath changed the response of aorta smooth muscle to NE. Displaying a gender dimorphism, BAT/WAT-derived NO, or other vasorelaxing factors, seem to reduce receptor density and/or affinity to NE. Adipose mast cell histochemistry also showed diversity in respect to subtype, gender, and cold exposure. Altogether, we found (i) a gender difference in adipose-released NO and in adipose mast cell histochemistry to cold exposure, and (ii) peripheral adipose tissues affect aortic contractile responses to NE likely by a NO-mediated pathway during cold exposure, suggesting that adipose tissue may limit cold-induced excessive vasoconstriction. Our ongoing study aims at the evaluation of whether aortic tunica adiposa itself could also contribute to this phenomenon.Adipobiology 2009; 1: 67-75

Morphological evaluation and clinical significance of the supracondylar process and supratrochlear foramen: an anatomic and radiological study

Background: In our literature review, we did not encounter any study examining the supracondylar process (SP) and the supratrochlear foramen (STF) with a three-dimensional (3D) reconstruction method. The present study aimed to evaluate SP and STF morphologically by employing the 3D reconstruction method and emphasize their clinical significance. Materials and methods: The research was carried out on dried human humeri of unknown sex and without pathological alterations. A total of 81 humeri (42 right, 39 left) were obtained from the Departments of Anatomy of Gazi University Faculty of Medicine and Lokman Hekim University Faculty of Medicine. The morphometric measurements of SP and STF were made with a digital vernier caliper. The computed tomography (CT) images acquired for radiological evaluation were analyzed with the 3D reconstruction method. Results: The narrower distal medullary canal widths of humeri with STF were found to be statistically significant. No statistically significant difference was found between the transverse diameters (TD), vertical diameters (VD), the distance of the medial edge to the medial epicondyle (ME), and the distance of the lateral edge to the lateral epicondyle (LE) of the supratrochlear foramen of the right and left humeri. Conclusions: The supracondylar process is often evaluated by mistake as a pathological condition of the bone, not as a normal anatomical variation. Knowing different shapes and dimensions, e.g., the TD and VD distance in which STF emerges, can assist in avoiding the misinterpretation of radiographs

Transition energy and lifetime for the ground state hyperfine splitting of high Z lithiumlike ions

The ground state hyperfine splitting values and the transition probabilities between the hyperfine structure components of high Z lithiumlike ions are calculated in the range $Z=49-83$. The relativistic, nuclear, QED and interelectronic interaction corrections are taken into account. It is found that the Bohr-Weisskopf effect can be eliminated in a combination of the hyperfine splitting values of the hydrogenlike and lithiumlike ions of an isotope. This gives a possibility for testing the QED effects in a combination of the strong electric and magnetic fields of the heavy nucleus. Using the experimental result for the $1s$ hyperfine splitting in ^{209}Bi^{82+}, the 2s hyperfine splitting in ^{209}Bi^{80+} is calculated to be \Delta E=0.7969(2) eV.Comment: The nuclear charge distribution correction \delta is corrected, 14 pages, Late

Variations in concerns reported on the Patient Concerns Inventory (PCI) in head and neck cancer patients from different health settings across the world

Background: The aim was to collate and contrast patient concerns from a range of different head and neck cancer follow-up clinics around the world. Also, we sought to explore the relationship, if any, between responses to the patient concerns inventory (PCI) and overall quality of life (QOL). Methods: Nineteen units participated with intention of including 100 patients per site as close to a consecutive series as possible in order to minimize selection bias. Results: There were 2136 patients with a median total number of PCI items selected of 5 (2-10). “Fear of the cancer returning” (39%) and “dry mouth” (37%) were most common. Twenty-five percent (524) reported less than good QOL. Conclusion: There was considerable variation between units in the number of items selected and in overall QOL, even after allowing for case-mix variables. There was a strong progressive association between the number of PCI items and QOL

Atomic Transport in Dense, Multi-Component Metallic Liquids

Pd43Ni10Cu27P0 has been investigated in its equilibrium liquid state with incoherent, inelastic neutron scattering. As compared to simple liquids, liquid PdNiCuP is characterized by a dense packing with a packing fraction above 0.5. The intermediate scattering function exhibits a fast relaxation process that precedes structural relaxation. Structural relaxation obeys a time-temperature superposition that extends over a temperature range of 540K. The mode-coupling theory of the liquid to glass transition (MCT) gives a consistent description of the dynamics which governs the mass transport in liquid PdNiCuP alloys. MCT scaling laws extrapolate to a critical temperature Tc at about 20% below the liquidus temperature. Diffusivities derived from the mean relaxation times compare well with Co diffusivities from recent tracer diffusion measurements and diffsuivities calculated from viscosity via the Stokes-Einstein relation. In contrast to simple metallic liquids, the atomic transport in dense, liquid PdNiCuP is characterized by a drastical slowing down of dynamics on cooling, a q^{-2} dependence of the mean relaxation times at intermediate q and a vanishing isotope effect as a result of a highly collective transport mechanism. At temperatures as high as 2Tc diffusion in liquid PdNiCuP is as fast as in simple liquids at the melting point. However, the difference in the underlying atomic transport mechanism indicates that the diffusion mechanism in liquids is not controlled by the value of the diffusivity but rather by that of the packing fraction