Higher-Order Spectral Clustering for Geometric Graphs

The present paper is devoted to clustering geometric graphs. While the standard spectral clustering is often not effective for geometric graphs, we present an effective generalization, which we call higher-order spectral clustering. It resembles in concept the classical spectral clustering method but uses for partitioning the eigenvector associated with a higher-order eigenvalue. We establish the weak consistency of this algorithm for a wide class of geometric graphs which we call Soft Geometric Block Model. A small adjustment of the algorithm provides strong consistency. We also show that our method is effective in numerical experiments even for graphs of modest size.Comment: 23 pages, 6 figure

Biopharmaceutical and pharmacokinetic aspects of statins used in the treatment of hyperlipidemia

Universitatea de Stat de Medicină şi Farmacie “Nicolae Testemiţanu” din Republica MoldovaIntroducere. Conform statisticilor OMS, bolile cardiovasculare reprezintă principala cauză a mortalităţii. Datele statistice arată că aproximativ 17 milioane de oameni, anual, decedează din cauza acestor afecţiuni. Pentru controlul acestor maladii, în prezent, sunt implimentate măsuri ce includ micşorarea nivelului de lipide de densitate joasă (LDL) şi a colesterolului, fapt ce previne apariţia aterosclerozei şi ulterior a complicaţiilor ei. Scopul lucrării. Evaluarea din punct de vedere biofarmaceutic şi farmacocinetic a slatinelor, utilizate în medicaţia hiperlipidemiilor. Material şi metode. Studiul analitic al bazelor de date şi reviul conceptual, comparativ al statisticilor şi literaturii naţionale şi internaţionale de specialitate. Rezultate. Conform clasificării ATC statinele sunt inhibitori selectivi de hidroximetil glutaril-CoA reductază. După proprietăţile fizico-chimice, statinele sunt pulberi insolubile în apă, cu masa moleculară între 400 şi 500 Da, denotă o permeabilitate şi absorbţie bună în mediul gastric şi joasă în intestin şi sânge, iar conform sistemului de clasificare biofarmaceutic, statinele se referă la clasa II (permeabilitate înaltă şi solubilitate joasă). în Nomenclatorul de Stat al Medicamentelor sunt înregistrate următoarele statine: atorvastatina, simvastatina, rosuvastatina, lovastatina, fluvastatina, preparate sub formă farmaceutică de comprimat. Biodisponibilitatea statinelor variază între 5-30%, sunt metabolizate extensiv la trecerea pasajului hepatic, dând naştere la metaboliţi activi; legarea de proteinele plasmatice este în proporţie de 90-98%. Timpul de înjumătăţire este de 1-4 ore, cu excepţia atorvastatinei (20 ore). Eliminarea preponderent are loc prin secreţie biliară, în urma tratamentului cu statine se constată reducerea colesterolului total cu 16-46%, LDL colesterolului cu 22­ 63%, a trigliceridelor cu 10-37% şi o creştere a valorilor de HDL colesterolul cu 2-14%. Concluzii. Statinele reprezintă o medicaţie de elecţie în hiperlipidemii asociate cu hipercolesterolemie.Introduction. According to WHO statistics, cardiovascular diseases are the leading cause of mortality. Statistics show that about 17 million people, every year, die due to these illnesses. Nowadays, for heart diseases control, are implemented measures which include lowering LDL and cholesterol levels, in order to prevent the occurrence of atherosclerosis and subsequently it complications. The aim of the study. Biopharmaceutical and pharmacokinetic evaluation of statins, used in the treatment of hyperlipidemia. Material and methods. Analytical study of databases, national and international scientific literature, conceptcomparative and statistics reviews. Results. According to the ATC classification, statins are selective inhibitors of hydroxymethylglutaryl-CoA reductase. As stated by physical-chemical properties, statins are water insoluble powders, with molecular weight between 400 and 500 Da, possess a good permeability and absorption in gastric media and low absorption in intestine and blood. Statins refer to the 2nd class of the Biopharmaceutical Classification System (low solubility and high permeability). The statins registered in the State Nomenclature of Drugs are: atrovastatin, simvastatin, rosuvastatin, lovastatin, fluvastatin, provided as compressed pharmaceutical formulations. The bioavailability of statins varies between 5-30%, statins are metabolized extensively by first pass effect, giving rise to active metabolites. Plasma protein binding is in a proportion of 90-98%. The half-life ranges from 1 to 4 hours, with the exception of atorvastatin (20 hours). Statins and their metabolites are eliminated mainly by biliary excretion. After administration of statins, a reduction of total cholesterol by 16-46%, LDL cholesterol by 22-63%, triglycerides by 10­ 37% and an increase of HDL cholesterol up to 2-14%, is recorded. Conclusions. Statins are first-choice medications in hyperlipidemia associated with hypercholesterolemia

Diagnosing and Augmenting Feature Representations in Correctional Inverse Reinforcement Learning

Robots have been increasingly better at doing tasks for humans by learning from their feedback, but still often suffer from model misalignment due to missing or incorrectly learned features. When the features the robot needs to learn to perform its task are missing or do not generalize well to new settings, the robot will not be able to learn the task the human wants and, even worse, may learn a completely different and undesired behavior. Prior work shows how the robot can detect when its representation is missing some feature and can, thus, ask the human to be taught about the new feature; however, these works do not differentiate between features that are completely missing and those that exist but do not generalize to new environments. In the latter case, the robot would detect misalignment and simply learn a new feature, leading to an arbitrarily growing feature representation that can, in turn, lead to spurious correlations and incorrect learning down the line. In this work, we propose separating the two sources of misalignment: we propose a framework for determining whether a feature the robot needs is incorrectly learned and does not generalize to new environment setups vs. is entirely missing from the robot's representation. Once we detect the source of error, we show how the human can initiate the realignment process for the model: if the feature is missing, we follow prior work for learning new features; however, if the feature exists but does not generalize, we use data augmentation to expand its training and, thus, complete the correction. We demonstrate the proposed approach in experiments with a simulated 7DoF robot manipulator and physical human corrections.Comment: 8 pages, 4 figure

RESPON POTENSIAL MEMBRAN SEL TELUR IKAN NILA (Oreochromis niloticus) AKIBAT TERKONTAMINASI TIMBAL (Pb)

Sel telur ikan nila memberikan respon yang berbeda-beda ketika diberikan variasi konsentrasi bahan pencemar timbal (Pb). Penelitian ini menggunakan mikroelektroda yang dihubungkan ke Picoscope untuk mengukur nilai potensial membran sel telur ikan nila. Hasil penelitian  menunjukkan bahwa sel telur ikan nila yang tercemar Pb akan menyebabkan terjadinya perubahan potensial membran sel. Konsentrasi Pb yang diberikan terdiri dari enam variasi yaitu 0 0,02ppm ; 0,03ppm; 0,05ppm; 0,1 ppm ; 0,5ppm; dan 1ppm. Telur ikan nila yang terpapar Pb dengan konsentrasi tertinggi 1ppm menyebabkan sel mengalami penurunan potensial membran yang signifikan yaitu -7,77 mV. Pada titik ini, sel telur ikan nila mengalami penurunan potensial membran hingga mengalami kematian sel

Optimizarea metodelor de hemostază şi adrenării vezicii urinare în adenomectomia transvezicală. Aspect economic

Summary Due to the appearance of a space for drainage between Foley’s catheter, tubs and urethra the proposed method of adenomectomy operation permits a better and adequate drainage of the bladder adenoma’s site. By this the post-surgical hospital treatment decreased considerably. Introducere. Hemostaza intraoperatorie şi drenarea căilor urinare este un moment principial, cu posibile consecinţe în perioada postoperatorie imediată şi în cea tardivă: hemoragii întra- şi postoperatorii, apariţia stricturilor uretrale, volumul medicaţiei aplicate şi durata aflării pacientului în staţionar. Material şi metodă. Metoda pentru hemostază, drenarea vezicii urinare (VU) şi a lojei adenomului de prostată (AP), a fost propusă pe 23.01.2001 de medicul B. Ipatii (inovaţia Nr. 695/15). Studiul de evaluare a metodei a fost realizat pe un lot de 200 pacienţi cu adenom de prostată, trataţi în Clinica Urologie IMSP SCM „Sfânta Treime”, Chişinău. Din numărul total de pacienţi, 100 au fost operaţi prin metoda clasică, iar 100 prin procedeul propus de noi. Metoda constă în următoarele: după enucleerea bim anuală a adenom ului şi hem ostază corespunzătoare, se perfectează revizia lojei pentru înlăturarea ţesutului restant. Porţiunile ambundent sângerânde se suturează cu catgut. Dacă loja este de dimensiuni mari, se suturează cu catgut mucoasă-mucoasă pentru a fi micşorată şi a permite cateterului Foley (CF) asigurarea hemostazei mecanice. Paralel cu CF, se instalează suplimentar un tub de perfuzie ce este fixat cu suturi de capron scoase prin VU la abdomen. VU se suturează ermetic. Astfel se formează un spaţiu între CF, tub şi mucoasa uretrei, ceea ce permite o drenare mai adecvată a lojei adenomului, a VU şi a uretrei, fapt ce permite ameliorarea evacuării cheagurilor de sânge, a ţesuturilor necrotizate, detritului. Catereul Foley şi tubul se menţine în uretră 7-9 zile, ceea ce permite instituirea unui lavaj, în caz de hemoragie. Rezultate şi concluzii. In urma aplicării metodei propuse nu au fost semnalate hemoragii majore cu tamponada vezicii urinare, stări febrile sau frisoane; nu au fost necesare hemotransfuzii. Vindecarea plăgii s-a realizat „per primam”, fără formarea de fistule urinare. La extragerea drenajului uretral micţiile au fost libere. Studiul efectuat retrospectiv referitor la durata de spitalizare postoperatorie a pacienţilor a demonstrat o eficacitate superioară a metodei propuse, în comparaţie cu metoda clasică. Astfel, în lotul I, durata medie de aflare a pacienţilor în spital a costituit 20,5 zile. In lotul II (perioada 2000-2004), pentru bolnavii operaţi prin metoda noastră, durata tratamentului în staţionar a constituit 11,3 zile. In concluzie, putem afirma că aspectul economic al metodei propuse este evident şi necesită studii suplimentare

Teaching Robots to Span the Space of Functional Expressive Motion

Our goal is to enable robots to perform functional tasks in emotive ways, be it in response to their users' emotional states, or expressive of their confidence levels. Prior work has proposed learning independent cost functions from user feedback for each target emotion, so that the robot may optimize it alongside task and environment specific objectives for any situation it encounters. However, this approach is inefficient when modeling multiple emotions and unable to generalize to new ones. In this work, we leverage the fact that emotions are not independent of each other: they are related through a latent space of Valence-Arousal-Dominance (VAD). Our key idea is to learn a model for how trajectories map onto VAD with user labels. Considering the distance between a trajectory's mapping and a target VAD allows this single model to represent cost functions for all emotions. As a result 1) all user feedback can contribute to learning about every emotion; 2) the robot can generate trajectories for any emotion in the space instead of only a few predefined ones; and 3) the robot can respond emotively to user-generated natural language by mapping it to a target VAD. We introduce a method that interactively learns to map trajectories to this latent space and test it in simulation and in a user study. In experiments, we use a simple vacuum robot as well as the Cassie biped

Diagnosis, Feedback, Adaptation: A Human-in-the-Loop Framework for Test-Time Policy Adaptation

Policies often fail due to distribution shift -- changes in the state and reward that occur when a policy is deployed in new environments. Data augmentation can increase robustness by making the model invariant to task-irrelevant changes in the agent's observation. However, designers don't know which concepts are irrelevant a priori, especially when different end users have different preferences about how the task is performed. We propose an interactive framework to leverage feedback directly from the user to identify personalized task-irrelevant concepts. Our key idea is to generate counterfactual demonstrations that allow users to quickly identify possible task-relevant and irrelevant concepts. The knowledge of task-irrelevant concepts is then used to perform data augmentation and thus obtain a policy adapted to personalized user objectives. We present experiments validating our framework on discrete and continuous control tasks with real human users. Our method (1) enables users to better understand agent failure, (2) reduces the number of demonstrations required for fine-tuning, and (3) aligns the agent to individual user task preferences.Comment: International Conference on Machine Learning (ICML) 202