Online Learning with Adversaries: A Differential-Inclusion Analysis

We introduce an observation-matrix-based framework for fully asynchronous online Federated Learning (FL) with adversaries. In this work, we demonstrate its effectiveness in estimating the mean of a random vector. Our main result is that the proposed algorithm almost surely converges to the desired mean $\mu.$ This makes ours the first asynchronous FL method to have an a.s. convergence guarantee in the presence of adversaries. We derive this convergence using a novel differential-inclusion-based two-timescale analysis. Two other highlights of our proof include (a) the use of a novel Lyapunov function to show that $\mu$ is the unique global attractor for our algorithm's limiting dynamics, and (b) the use of martingale and stopping-time theory to show that our algorithm's iterates are almost surely bounded.Comment: 6 pages, 2 figure

Does Momentum Help? A Sample Complexity Analysis

Momentum methods are popularly used in accelerating stochastic iterative methods. Although a fair amount of literature is dedicated to momentum in stochastic optimisation, there are limited results that quantify the benefits of using heavy ball momentum in the specific case of stochastic approximation algorithms. We first show that the convergence rate with optimal step size does not improve when momentum is used (under some assumptions). Secondly, to quantify the behaviour in the initial phase we analyse the sample complexity of iterates with and without momentum. We show that the sample complexity bound for SA without momentum is $\tilde{\mathcal{O}}(\frac{1}{\alpha\lambda_{min}(A)})$ while for SA with momentum is $\tilde{\mathcal{O}}(\frac{1}{\sqrt{\alpha\lambda_{min}(A)}})$, where $\alpha$ is the step size and $\lambda_{min}(A)$ is the smallest eigenvalue of the driving matrix $A$. Although the sample complexity bound for SA with momentum is better for small enough $\alpha$, it turns out that for optimal choice of $\alpha$ in the two cases, the sample complexity bounds are of the same order

Malin and laforin are essential components of a protein complex that protects cells from thermal stress

The heat-shock response is a conserved cellular process characterized by the induction of a unique group of proteins known as heat-shock proteins. One of the primary triggers for this response, at least in mammals, is heat-shock factor 1 (HSF1) – a transcription factor that activates the transcription of heat-shock genes and confers protection against stress-induced cell death. In the present study, we investigated the role of the phosphatase laforin and the ubiquitin ligase malin in the HSF1-mediated heat-shock response. Laforin and malin are defective in Lafora disease (LD), a neurodegenerative disorder associated with epileptic seizures. Using cellular models, we demonstrate that these two proteins, as a functional complex with the co-chaperone CHIP, translocate to the nucleus upon heat shock and that all the three members of this complex are required for full protection against heat-shock-induced cell death. We show further that laforin and malin interact with HSF1 and contribute to its activation during stress by an unknown mechanism. HSF1 is also required for the heat-induced nuclear translocation of laforin and malin. This study demonstrates that laforin and malin are key regulators of HSF1 and that defects in the HSF1-mediated stress response pathway might underlie some of the pathological symptoms in LD

A case study of an adverse drug reaction caused by long term use of proton pump inhibitors

Proton pump inhibitors (PPI) are the class of drugs used to treat a wide variety of disorders related to the stomach's acid production. Although it is considered safe for short term use, reports revealed that many serious life-threatening adverse reactions occurred from long term use. Here we report a case of hypomagnesemia and hypocalcemia induced by long-term use of PPIs in a patient with crest syndrome. From his past history, it was revealed that he was on pantoprazole 40 mg for more than 3 months. While he was admitted here for other complaints, we were able to discover that he had hypomagnesemia defined by low magnesium level of 1.3 mg/dL. As a consequence, he also showed signs of hypocalcemia with a low calcium level of 7 mg/dL. A peculiar complaint seen in this patient was three episodes of supraventricular tachycardia which is the most common cardiac manifestations of hypomagnesemia. As a conclusion, hypomagnesemia can sometimes be asymptomatic and cause unspecific and serious manifestations such as asthenia, paresthesia’s, seizures, arrhythmias, and cardiac arrest. Hence routine monitoring of serum magnesium and calcium levels should be made mandatory in practice for patients on long term use of PPI. Besides, it should be kept in mind that interchanging PPI class with histamine 2 receptor antagonist or fitful use of PPI may not cause hypomagnesemia

Simultaneous expression of regulatory genes associated with specific drought‐adaptive traits improves drought adaptation in peanut

Adaptation of crops to drought-prone rain-fed conditions can be achieved by improving plant traits such as efficient water mining (by superior root characters) and cellular-level tolerance mechanisms. Pyramiding these drought-adaptive traits by simultaneous expression of genes regulating drought-adaptive mechanisms has phenomenal relevance in improving stress tolerance. In this study, we provide evidence that peanut transgenic plants expressing Alfalfa zinc finger 1 (Alfin1), a root growth-associated transcription factor gene, Pennisetum glaucum heat-shock factor (PgHSF4) and Pea DNA helicase (PDH45) involved in protein turnover and protection showed improved tolerance, higher growth and productivity under drought stress conditions. Stable integration of all the transgenes was noticed in transgenic lines. The transgenic lines showed higher root growth, cooler crop canopy air temperature difference (less CCATD) and higher relative water content (RWC) under drought stress. Low proline levels in transgenic lines substantiate the maintenance of higher water status. The survival and recovery of transgenic lines was significantly higher under gradual moisture stress conditions with higher biomass. Transgenic lines also showed significant tolerance to ethrel-induced senescence and methyl viologen-induced oxidative stress. Several stress-responsive genes such as heat-shock proteins (HSPs), RING box protein-1 (RBX1), Aldose reductase, late embryogenesis abundant-5 (LEA5) and proline-rich protein-2 (PRP2), a gene involved in root growth, showed enhanced expression under stress in transgenic lines. Thus, the simultaneous expression of regulatory genes contributing for drought-adaptive traits can improve crop adaptation and productivity under water-limited conditions

Assessment of Mitochondrial Dysfunction in Lungs from Rats Exposed to Hyperoxia and the Efficacy of Duroquinone

Dissipation of mitochondrial membrane potential (ΔΨm) is a hallmark of mitochondrial dysfunction. The objective of this thesis was to use a previously developed experimental-computational approach to estimate tissue ΔΨm in intact lungs of rats exposed to hyperoxia, and to evaluate the ability of duroquinone (DQ) to reverse any hyperoxia-induced depolarization of lung Ψm. Rats were exposed to hyperoxia (\u3e95% O2) or normoxia (room air) for 48 hrs, after which lungs were excised and connected to a ventilation-perfusion system. The experimental protocol consisted of measuring the concentration of the fluorescent dye rhodamine 6G (R6G) during three single-pass phases: loading, washing, and uncoupling, in which the lungs were perfused with and without R6G, and with the mitochondrial uncoupler FCCP, respectively. For normoxic lungs, the protocol was repeated with 1) rotenone (complex I inhibitor), 2) rotenone and either DQ or its vehicle (DMSO), and 3) rotenone, glutathione (GSH), and either DQ or DMSO added to the perfusate. Hyperoxic lungs were studied with and without DQ and GSH added to the perfusate. Computational modeling was used to estimate lung ΔΨm from R6G data. The results show that rat exposure to hyperoxia caused a partial depolarization (-38 mV) of lung ΔΨm, and complex I inhibition depolarized lung ΔΨm by -90 mV. Results also demonstrate the efficacy of DQ to fully reverse both rotenone-induced and hyperoxia-induced lung ΔΨm depolarization. This study demonstrates hyperoxia-induced ΔΨm depolarization in intact lungs, and the utility of this approach for assessing the impact of potential therapies such as exogenous quinones that target mitochondria in intact lung

Online Learning with Adversaries: A Differential Inclusion Analysis

We consider the measurement model Y = AX, where X and, hence, Y are random variables and A is an a priori known tall matrix. At each time instance, a sample of one of Y 's coordinates is available, and the goal is to estimate µ := E[X] via these samples. However, the challenge is that a small but unknown subset of Y 's coordinates are controlled by adversaries with infinite power: they can return any real number each time they are queried for a sample. For such an adversarial setting, we propose the first asynchronous online algorithm that converges to µ almost surely. We prove this result using a novel differential inclusion based two-timescale analysis. Two key highlights of our proof include: (a) the use of a novel Lyapunov function for showing that µ is the unique global attractor for our algorithm's limiting dynamics, and (b) the use of martingale and stopping time theory to show that our algorithm's iterates are almost surely bounded

Prevalence of prescribing antacids in children treated under general anaesthesia: A retrospective cohort study

Background: There are a few instances of dental problems in children that can't be handled effectively in the clinic and should be treated in the hospital setup under general anesthesia and the patients are prescribed painkillers and antacids as postoperative medications. Children treated under general anesthesia are common in pediatric dentistry but prescription of antacids is not very common. Aim: To find the Prevalence of prescribing antacids in children treated under general anaesthesia. Materials and Methods: The study was done in private dental college and hospitals, Chennai India. Patient records were reviewed and the data of 300 patients between September 2020 and February 2021were analyzed. Total sample data was 73 and was minimized by inclusion of all available data. Collected Data were analyzed using SPSS statistical software. Data analysis done using chi-square test and p-value was set as 0.05 as level of significance. Results: According to the findings of this research, Among 73 children treated under General anesthesia, 32% had antacid prescribed, while 68% were not prescribed with antacids .while 11-18 years were the most prescribed with antacids than other groups. Conclusion: 32% of the children treated under general anaesthesia were prescribed antacids