Comparing dynamics: deep neural networks versus glassy systems

We analyze numerically the training dynamics of deep neural networks (DNN) by using methods developed in statistical physics of glassy systems. The two main issues we address are (1) the complexity of the loss landscape and of the dynamics within it, and (2) to what extent DNNs share similarities with glassy systems. Our findings, obtained for different architectures and datasets, suggest that during the training process the dynamics slows down because of an increasingly large number of flat directions. At large limes, when the loss is approaching zero, the system diffuses at the bottom of the landscape. Despite some similarities with the dynamics of mean-field glassy systems, in particular, the absence of barrier crossing, we find distinctive dynamical behaviors in the two cases, showing that the statistical properties of the corresponding loss and energy landscapes arc different. In contrast, when the network is under-parametrized we observe a typical glassy behavior, thus suggesting the existence of different phases depending on whether the network is under-parametrized or over-parametrized

Ethnobotany in the Nepal Himalaya

<p>Abstract</p> <p>Background</p> <p>Indigenous knowledge has become recognized worldwide not only because of its intrinsic value but also because it has a potential instrumental value to science and conservation. In Nepal, the indigenous knowledge of useful and medicinal plants has roots in the remote past.</p> <p>Methods</p> <p>The present study reviews the indigenous knowledge and use of plant resources of the Nepal Himalayas along the altitudinal and longitudinal gradient. A total of 264 studies focusing on ethnobotany, ethnomedicine and diversity of medicinal and aromatic plants, carried out between 1979 and 2006 were consulted for the present analysis. In order to cross check and verify the data, seven districts of west Nepal were visited in four field campaigns.</p> <p>Results</p> <p>In contrast to an average of 21–28% ethnobotanically/ethnomedicinally important plants reported for Nepal, the present study found that up to about 55% of the flora of the study region had medicinal value. This indicates a vast amount of undocumented knowledge about important plant species that needs to be explored and documented. The richness of medicinal plants decreased with increasing altitude but the percentage of plants used as medicine steadily increased with increasing altitude. This was due to preferences given to herbal remedies in high altitude areas and a combination of having no alternative choices, poverty and trust in the effectiveness of folklore herbal remedies.</p> <p>Conclusion</p> <p>Indigenous knowledge systems are culturally valued and scientifically important. Strengthening the wise use and conservation of indigenous knowledge of useful plants may benefit and improve the living standard of poor people.</p

Outcomes After TIPS for Ascites and Variceal Bleeding in a Contemporary Era—An ALTA Group Study

IntroductionAdvances in transjugular intrahepatic portosystemic shunt (TIPS) technology have led to expanded use. We sought to characterize contemporary outcomes of TIPS by common indications.MethodsThis was a multicenter, retrospective cohort study using data from the Advancing Liver Therapeutic Approaches study group among adults with cirrhosis who underwent TIPS for ascites/hepatic hydrothorax (ascites/HH) or variceal bleeding (2010-2015). Adjusted competing risk analysis was used to assess post-TIPS mortality or liver transplantation (LT).ResultsAmong 1,129 TIPS recipients, 58% received TIPS for ascites/HH and 42% for variceal bleeding. In patients who underwent TIPS for ascites/HH, the subdistribution hazard ratio (sHR) for death was similar across all Model for End-Stage Liver Disease Sodium (MELD-Na) categories with an increasing sHR with rising MELD-Na. In patients with TIPS for variceal bleeding, MELD-Na ≥20 was associated with increased hazard for death, whereas MELD-Na ≥22 was associated with LT. In a multivariate analysis, serum creatinine was most significantly associated with death (sHR 1.2 per mg/dL, 95% confidence interval [CI] 1.04-1.4 and 1.37, 95% CI 1.08-1.73 in ascites/HH and variceal bleeding, respectively). Bilirubin and international normalized ratio were most associated with LT in ascites/HH (sHR 1.23, 95% CI 1.15-1.3; sHR 2.99, 95% CI 1.76-5.1, respectively) compared with only bilirubin in variceal bleeding (sHR 1.06, 95% CI 1.00-1.13).DiscussionMELD-Na has differing relationships with patient outcomes dependent on TIPS indication. These data provide new insights into contemporary predictors of outcomes after TIPS

Nonalcoholic Fatty Liver Disease and Diabetes Mellitus Are Associated With Post-Transjugular Intrahepatic Portosystemic Shunt Renal Dysfunction: An Advancing Liver Therapeutic Approaches Group Study.

Transjugular intrahepatic portosystemic shunt (TIPS) is an effective intervention for portal hypertensive complications, but its effect on renal function is not well characterized. Here we describe renal function and characteristics associated with renal dysfunction at 30 days post-TIPS. Adults with cirrhosis who underwent TIPS at 9 hospitals in the United States from 2010 to 2015 were included. We defined "post-TIPS renal dysfunction" as a change in estimated glomerular filtration rate (ΔeGFR) ≤-15 and eGFR&nbsp;≤&nbsp;60&nbsp;mL/min/1.73&nbsp;m2 or new renal replacement therapy (RRT) at day 30. We identified the characteristics associated with post-TIPS renal dysfunction by logistic regression and evaluated survival using adjusted competing risk regressions. Of the 673 patients, the median age was 57 years, 38% of the patients were female, 26% had diabetes mellitus, and the median MELD-Na was 17. After 30 days post-TIPS, 66 (10%) had renal dysfunction, of which 23 (35%) required new RRT. Patients with post-TIPS renal dysfunction, compared with those with stable renal function, were more likely to have nonalcoholic fatty liver disease (NAFLD; 33% versus 17%; P&nbsp;=&nbsp;0.01) and comorbid diabetes mellitus (42% versus 24%; P&nbsp;=&nbsp;0.001). Multivariate logistic regressions showed NAFLD (odds ratio [OR], 2.04; 95% confidence interval [CI], 1.00-4.17; P&nbsp;=&nbsp;0.05), serum sodium (Na; OR, 1.06 per mEq/L; 95% CI, 1.01-1.12; P&nbsp;=&nbsp;0.03), and diabetes mellitus (OR, 2.04; 95% CI, 1.16-3.61; P&nbsp;=&nbsp;0.01) were associated with post-TIPS renal dysfunction. Competing risk regressions showed that those with post-TIPS renal dysfunction were at a higher subhazard of death (subhazard ratio, 1.74; 95% CI, 1.18-2.56; P&nbsp;=&nbsp;0.01). In this large, multicenter cohort, we found NAFLD, diabetes mellitus, and baseline Na associated with post-TIPS renal dysfunction. This study suggests that patients with NAFLD and diabetes mellitus undergoing TIPS evaluation may require additional attention to cardiac and renal comorbidities before proceeding with the procedure