Memory Aware Synapses: Learning what (not) to forget

Humans can learn in a continuous manner. Old rarely utilized knowledge can be overwritten by new incoming information while important, frequently used knowledge is prevented from being erased. In artificial learning systems, lifelong learning so far has focused mainly on accumulating knowledge over tasks and overcoming catastrophic forgetting. In this paper, we argue that, given the limited model capacity and the unlimited new information to be learned, knowledge has to be preserved or erased selectively. Inspired by neuroplasticity, we propose a novel approach for lifelong learning, coined Memory Aware Synapses (MAS). It computes the importance of the parameters of a neural network in an unsupervised and online manner. Given a new sample which is fed to the network, MAS accumulates an importance measure for each parameter of the network, based on how sensitive the predicted output function is to a change in this parameter. When learning a new task, changes to important parameters can then be penalized, effectively preventing important knowledge related to previous tasks from being overwritten. Further, we show an interesting connection between a local version of our method and Hebb's rule,which is a model for the learning process in the brain. We test our method on a sequence of object recognition tasks and on the challenging problem of learning an embedding for predicting $$ triplets. We show state-of-the-art performance and, for the first time, the ability to adapt the importance of the parameters based on unlabeled data towards what the network needs (not) to forget, which may vary depending on test conditions.Comment: ECCV 201

Biochemical activities of lactose-derived prebiotics — a review

In the dairy industry different types of prebiotics, such galacto-oligosaccharide, lactulose, lactosucrose, tagatose, lactitol, lactobiono- and glucono-δ-lactone are synthesized through different chemical and biochemical reactions (hydrolysis, transgalactosylation, isomerization, fructosyl-transfer, reduction, and oxidation) as well as microbial fermentation processes using raw whey or isolated lactose as feedstock. Lactose-derived prebiotics have several functional and nutritional values. The biochemical activities of lactose-based prebiotics are expressed in the presence of probiotics (lactic acid bacteria, yeasts, Bacillus spp.). Galacto-oligosaccharide and lactosucrose reduce the risk of bowel disorder (diarrhea), inflammatory bowel disease (ulcerative colitis and crohn’s disease), and colon cancer. Galacto-oligosaccharide helps colonic absorption of minerals (iron, magnesium and calcium) and prevents osteoporosis. Lactulose, galacto-oligosaccharide, and lactitol promote laxative activity. Furthermore, lactulose may decrease the risk of hepatic encephalopathy. Prebiotics have low calorific value and glycemic index. Galacto-oligosaccharide and tagatose reduce the risks of hyperglycemia (Type 2 diabetes) and low density lipid (lipoprotein) accumulation in blood stream. Moreover, prebiotics improve immunomodulation, which reduces the risk of respiratory infection and allergies. This review describes unique biochemical mechanisms of several types of lactose-derived prebiotics

Low fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) diet improves symptoms in adults suffering from irritable bowel syndrome (IBS) compared to standard IBS diet: A meta-analysis of clinical studies

BACKGROUND: Irritable bowel syndrome (IBS) and functional digestive tract disorders, e.g. functional bloating, carbohydrate maldigestion and intolerances, are very common disorders frequently causing significant symptoms that challenge health care systems. A low Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols (FODMAP) diet is one of the possible therapeutic approaches for decreasing abdominal symptoms and improving quality of life. OBJECTIVES: We aimed to meta-analyze data on the therapeutic effect of a low-FODMAP diet on symptoms of IBS and quality of life and compare its effectiveness to a regular, standard IBS diet with high FODMAP content, using a common scoring system, the IBS Symptom Severity Score (IBS-SSS). METHODS: A systematic literature search was conducted in PubMed, EMBASE and the Cochrane Library as well as in the references in a recent meta-analysis. Adult patients diagnosed with IBS according to the Rome II, Rome III, Rome IV or NICE criteria were included in the analysis. STATISTICAL METHODS: Mean differences with 95% confidence intervals were calculated from studies that contained means, standard deviation (SD) or mean differences and SD of differences and p-values. A random effect model was used because of the heterogeneity (Q test (chi2) and I2 indicator). A p-value of less than 0.05 was chosen to indicate a significant difference. RESULTS: The literature search yielded 902 publications, but only 10 were eligible for our meta-analysis. Both regular and low-FODMAP diets proved to be effective in IBS, but post-diet IBS-SSS values were significantly lower (p = 0.002) in the low-FODMAP group. The low-FODMAP diet showed a correlation with the improvement of general symptoms (by IBS-SSS) in patients with IBS. CONCLUSIONS: This meta-analysis provides high-grade evidence of an improved general symptom score among patients with irritable bowel syndrome who have maintained a low-FODMAP diet compared to those on a traditional IBS diet, therefore showing its superiority to regular IBS dietary therapy. These data suggest that a low-FODMAP diet with dietitian control can be a candidate for first-line therapeutic modality in IBS. Because of a lack of data, well-planned randomized controlled studies are needed to ascertain the correlation between improvement of separate key IBS symptoms and the effect of a low-FODMAP diet

Quantitative susceptibility mapping for characterization of intraplaque hemorrhage and calcification in carotid atherosclerotic disease

Background: Carotid artery intraplaque hemorrhage (IPH), an unstable component of atherosclerosis, is associated with an increased risk of stroke. Purpose: To investigate quantitative susceptibility mapping (QSM) as a tool for the evaluation of IPH and calcification in vivo. Study Type: Prospective. Population: Ten healthy volunteers and 15 patients. Field Strength/Sequence: 3.0T Susceptibility‐weighted imaging (SWI), magnetization‐prepared rapid acquisition with gradient echo (MP‐RAGE), T1‐weighted sampling perfection with application of optimized contrasts using different flip angle evolution (T1‐SPACE), T2‐weighted turbo spin‐echo (T2WI), and time‐of‐flight (TOF) sequences. Assessment: The vessel wall area of the carotid artery was measured with QSM and compared with T1‐SPACE on healthy volunteers. Four radiologists, blinded to clinical history and patient identity, determined the presence and area of IPH on MP‐RAGE and QSM, as well as the area of calcification on T1‐SPACE and QSM. Statistical Tests: Bland–Altman analysis, Pearson correlation coefficients, linear regression analyses were performed to evaluate the concordance of area measurements. Cohen's kappa (κ) was analyzed to determine the agreement between IPH detections. The paired t ‐test was used to compare the group differences. Results: In 423 matched slices, 20.1% (85/423) and 19.6% (83/423) were detected to have IPH on MP‐RAGE and QSM, respectively. IPH detection by QSM and MP‐RAGE showed good agreement (κ = 0.822, P   Data Conclusion: QSM is a novel imaging tool for the identification of IPH in patients with carotid atherosclerosis and enables differentiation of IPH and calcification. Evidence Level: 1. Technical Efficacy: Stage 1.</p