Is Simple Better? Revisiting Non-linear Matrix Factorization for Learning Incomplete Ratings

Matrix factorization techniques have been widely used as a method for collaborative filtering for recommender systems. In recent times, different variants of deep learning algorithms have been explored in this setting to improve the task of making a personalized recommendation with user-item interaction data. The idea that the mapping between the latent user or item factors and the original features is highly nonlinear suggest that classical matrix factorization techniques are no longer sufficient. In this paper, we propose a multilayer nonlinear semi-nonnegative matrix factorization method, with the motivation that user-item interactions can be modeled more accurately using a linear combination of non-linear item features. Firstly, we learn latent factors for representations of users and items from the designed multilayer nonlinear Semi-NMF approach using explicit ratings. Secondly, the architecture built is compared with deep-learning algorithms like Restricted Boltzmann Machine and state-of-the-art Deep Matrix factorization techniques. By using both supervised rate prediction task and unsupervised clustering in latent item space, we demonstrate that our proposed approach achieves better generalization ability in prediction as well as comparable representation ability as deep matrix factorization in the clustering task.Comment: version

Simplifying Sparse Expert Recommendation by Revisiting Graph Diffusion

Community Question Answering (CQA) websites have become valuable knowledge repositories where individuals exchange information by asking and answering questions. With an ever-increasing number of questions and high migration of users in and out of communities, a key challenge is to design effective strategies for recommending experts for new questions. In this paper, we propose a simple graph-diffusion expert recommendation model for CQA, that can outperform state-of-the art deep learning representatives and collaborative models. Our proposed method learns users' expertise in the context of both semantic and temporal information to capture their changing interest and activity levels with time. Experiments on five real-world datasets from the Stack Exchange network demonstrate that our approach outperforms competitive baseline methods. Further, experiments on cold-start users (users with a limited historical record) show our model achieves an average of ~ 30% performance gain compared to the best baseline method

Clinico-radiological pattern of pulmonary tuberculosis with diabetes mellitus

Background: The link between diabetes mellitus and tuberculosis has been recognised for centuries. There is growing evidence that diabetes mellitus is an important risk factor for tuberculosis and might affect disease presentation and treatment response. The increase in burden of tuberculosis (TB) and diabetes mellitus (DM) is hitting certain Asian countries harder than other areas. In a global estimate, 15% of all TB cases could be attributable to DM, with 40% of those cases coming from India and China.Methods: It is a cross-sectional observational study with 50 TB patients with DM admitted in department of respiratory medicine Smt. B. K. Shah Medical Institute and Research Centre, Piparia, Waghodia, Vadodara, Gujarat, India total 6 months duration patients were included in the study (2015).Results: Total 50 cases were included in the study. The ratio of male: female was 7:3. Age group of 40 years and 60 years was high. Haemoptysis and weight loss were major complaints. There was a higher involvement of lower lung field (56%) as compared to upper lung field. Bilateral involvement was present in (18%). Cavitary lesions were present in (18%) cases and were more frequently confined to upper lung field (62%,5/9). Total 27 patients of pulmonary TB were first time detected with DM among them 20 patients had higher bacillary load (sputum >2+) and out of 27 newly detected DM patient 15 required insulin.Conclusions: Tuberculosis and DM have strong correlation and patients with diabetes mellitus has high probability of getting infected with tuberculosis

Comparison of the spatial QRS-T angle derived from digital ECGs recorded using conventional electrode placement with that derived from Mason-Likar electrode position

Background: The spatial QRS-T angle is ideally derived from orthogonal leads. We compared the spatial QRS-T angle derived from orthogonal leads reconstructed from digital 12-lead ECGs and from digital Holter ECGs recorded with the Mason-Likar (M-L) electrode positions. Methods and results: Orthogonal leads were constructed by the inverse Dower method and used to calculate spatial QRS-T angle by (1) a vector method and (2) a net amplitude method, in 100 volunteers. Spatial QRS-T angles from standard and M-L ECGs differed significantly (57° ± 18° vs 48° ± 20° respectively using net amplitude method and 53° ± 28° vs 48° ± 23° respectively by vector method; p < 0.001). Difference in amplitudes in leads V4–V6 was also observed between Holter and standard ECGs, probably due to a difference in electrical potential at the central terminal. Conclusion: Mean spatial QRS-T angles derived from standard and M-L lead systems differed by 5°–9°. Though statistically significant, these differences may not be clinically significant

ATORVASTATIN VS ROSUVASTATIN; FENOFIBRATE AS AN ADD ON: AN EXPLORATORY STUDY

Objective: Statins being the first choice drug for dyslipidaemia, the quest for better one among all has always been and still a question for research in the field of medicine. Objective­ The objective of our study was to find out the best statin among the two, Atorvastatin and Rosuvastatin, in terms of efficacy and safety; alone or in combination with Fenofibrate for the management of dyslipidaemia. Methods: This was an open label, randomized, parallel group, prospective comparative study, carried out in patients in two groups treated with Atorvastatin and Rosuvastatin (10mg each) for 6 weeks, after which Fenofibrate (67mg) was added as an add on therapy in either group for the next 4 weeks before and after treatment. Results: After the treatment, the TC, TG, LDL- C, HDL- C and Non HDL- C were comparable between two groups. The changes in the levels of TC were -15.90±5.16 (-8.53%) vs -20.70±4.83 (-11.32%) respectively in groups treated with Atorvastatin (group I) and Rosuvastatin (group II). Changes in TGs were -11.60±4.16 (-7.46%) vs -15.10±5.18 (-9.99%), respectively; change in LDL- C were -16.90±3.58 (-15.31%) vs -13.0±3.04 (-11.56%) respectively; change in HDL- C were +6.75±0.86 (+18.72%) vs +9.0±1.22 (+23.72%) respectively in each group; change in Non HDL- C were found to be -6.90±4.83 (-4.4%) vs -7.8±4.78 (-5.05%) respectively in groups I and II. After the addition of Fenofibrate (67mg) there were no significant changes in the different parameters of serum lipid profile. Conclusion: The result of our study suggests that Rosuvastatin (10mg) was more efficacious than Atorvastatin (10mg) in lipid lowering effect and HDL- C raising effect but should be used with great caution and care in patients with uncontrolled hyperglycaemia and in those with compromised hepatic status. Further addition of Fenofibrate (67mg) didn't make any significant difference in the result

Multithermal apparent damping of slow waves due to strands with a Gaussian temperature distribution

Context. Slow waves in solar coronal loops are strongly damped. The current theory of damping by thermal conduction cannot explain some observational features.\n Aims. We investigate the propagation of slow waves in a coronal loop built up from strands of different temperatures. \n Methods. We consider the loop to have a multithermal, Gaussian temperature distribution. The different propagation speeds in different strands lead to an multithermal apparent damping of the wave, similar to observational phase mixing. We use an analytical model to predict the damping length and propagation speed for the slow waves, including in imaging with filter telescopes. \n Results. We compare the damping length due to this multithermal apparent damping with damping due to thermal conduction and find that the multithermal apparent damping is more important for shorter period slow waves. We have found the influence of instrument filters on the wave's propagation speed and damping. This allows us to compare our analytical theory to forward models of numerical simulations. \n Conclusions. We find that our analytical model matches the numerical simulations very well. Moreover, we offer an outlook for using the slow wave properties to infer the loop's thermal properties.Comment: accepted for publication in Astronomy & Astrophysic

Electrophoretic Studies of Biologically Important Mixed Metal – Ascorbic Acid –Nitrilotriacetate Complexes

Quantitative indication of a complex formation comes from the estimation of the stability or formation constants characterizing the equilibria corresponding to the successive addition of ligands. The binary equilibria of metal (II) / (III)–ascorbic acid and also mixed equilibria metal (II) / (III)–ascorbic acid–NTA have been studied using ionophoretic technique. The stability constants of metal–ascorbic acid binary complexes are found to be 103.77, 102.47,102.27 and that of metal–ascorbic acid–NTA mixed complexes have been found to be 106.05, 105.93, 105.75, for Fe(III), Cu(II) and Co(II) complexes, respectively at 25 °C and ionic strength Ic = 0.1 mol dm–3 (HClO4). (doi: 10.5562/cca1778

Quantum dot photonic crystal detectors

In this paper we report the use of a photonic crystal resonant cavity to increase the quantum efficiency, detectivity (D*) and the background limited infrared photodetector (BLIP) temperature of a quantum dot detector. The photonic crystal is incorporated in InAs/InGaAs/GaAs dots-in-well (DWELL) detector using Electron beam lithography. From calibrated blackbody measurements, the conversion efficiency of the detector with the photonic crystal (DWELL-PC) is found to be 58.5% at -2.5 V while the control DWELL detectors have quantum efficiency of 7.6% at the same bias. We observed no significant reduction in the dark current of the photonic crystal devices compared to the normal structure. The generation-recombination limited D* at 77K with a 300K F1.7 background, is estimated to be 6 x 10^(10) cm Hz^(1/2)/W at -3V bias for the DWELL-PC which is a factor of 20 higher than that of the control sample. We also observed a 20% increase in the BLIP temperature for the DWELL-PCs