Exploration via Elliptical Episodic Bonuses

In recent years, a number of reinforcement learning (RL) methods have been proposed to explore complex environments which differ across episodes. In this work, we show that the effectiveness of these methods critically relies on a count-based episodic term in their exploration bonus. As a result, despite their success in relatively simple, noise-free settings, these methods fall short in more realistic scenarios where the state space is vast and prone to noise. To address this limitation, we introduce Exploration via Elliptical Episodic Bonuses (E3B), a new method which extends count-based episodic bonuses to continuous state spaces and encourages an agent to explore states that are diverse under a learned embedding within each episode. The embedding is learned using an inverse dynamics model in order to capture controllable aspects of the environment. Our method sets a new state-of-the-art across 16 challenging tasks from the MiniHack suite, without requiring task-specific inductive biases. E3B also matches existing methods on sparse reward, pixel-based Vizdoom environments, and outperforms existing methods in reward-free exploration on Habitat, demonstrating that it can scale to high-dimensional pixel-based observations and realistic environments

The NetHack learning environment

Progress in Reinforcement Learning (RL) algorithms goes hand-in-hand with the development of challenging environments that test the limits of current methods. While existing RL environments are either sufficiently complex or based on fast simulation, they are rarely both. Here, we present the NetHack Learning Environment (NLE), a scalable, procedurally generated, stochastic, rich, and challenging environment for RL research based on the popular single-player terminal-based roguelike game, NetHack. We argue that NetHack is sufficiently complex to drive long-term research on problems such as exploration, planning, skill acquisition, and language-conditioned RL, while dramatically reducing the computational resources required to gather a large amount of experience. We compare NLE and its task suite to existing alternatives, and discuss why it is an ideal medium for testing the robustness and systematic generalization of RL agents. We demonstrate empirical success for early stages of the game using a distributed Deep RL baseline and Random Network Distillation exploration, alongside qualitative analysis of various agents trained in the environment. NLE is open source and available at https://github.com/facebookresearch/nle

Optimizing surgical techniques in extra-anatomical ilio-femoral bypasses

Scopul lucrării. Bypass-ul extraanatomic ilio-femural crossover este o procedura chirurgicala utilizată pentru revascularizarea segmentului aorto-femural, când intervențiile endovasculare nu sunt posibile, iar aplicarea unui bypass aorto sau ilio-femural este dificilă sau chiar imposibilă din cauza condițiilor tehnice sau a stării pacientului. Scopul este studierea rezultatelor precoce și tardive pentru favorizarea unor schimbări și implementarea unor gesturi tehnice în aplicarea bypass-urilor crossover ilio-femural, pentru a crea o geometrie cât mai fiziologică ce poate oferi o soluție durabilă pe termen lung. Materiale și metode. Pe parcursul anilor 2001-2022 au fost efectuate 142 bypass-uri crossover ilio-femurale. Rezultate. În perioada postoperatorie a fost un singur deces și s-au efectuat 3 amputații. Au fost analizate duplex scanările și CT angiografiile în primele 12 luni postoperatorii, pentru aprecierea altor leziuni aterosclerotice, care ar necesita revascularizare deschisă s-au endovasculară atît in bazinul recipient cât și cel donator. Totodată, a fost apreciata poziția și forma bypass-ului ce a dus la folosirea ulterioară a unor noi procedee tehnice ce diferă de cele descrise anterior. Concluzii. Optimizarea tehnicilor chirurgicale creând o geometrie cât mai fiziologică, excluderea maximală a angulărilor stenozante ale grefei poate oferi bypass-ului extraanatomic crossover ilio-femural o durabilitate îndelungată. Acest lucru poate favoriza creșterea frecvenței indicațiilor la folosirea bypass-urilor crossover ilio-femural.Aim of study. The extra-anatomic ilio-femoral crossover bypass is a surgical procedure used for revascularizing the aorto-femoral segment when endovascular interventions are not possible, and when applying an aorto- or ilio-femoral bypass is difficult or even impossible due to technical conditions or the patient's condition. The aim was to study the early and late outcomes to promote changes and implement technical gestures in the application of ilio-femoral crossover bypasses, aiming to create a more physiological geometry that can provide a durable long-term solution. Materials and methods. Between 2001 and 2022, a total of 142 ilio-femoral crossover bypasses were performed. Results. There was one death and three amputations in the postoperative period. Duplex scans and CT angiography were analyzed in the first 12 months postoperatively to assess other atherosclerotic lesions that would require open or endovascular revascularization in both the recipient and donor areas. Additionally, the position and shape of the bypass were evaluated, leading to the subsequent use of new technical procedures that differ from those previously described. Conclusions. Optimizing surgical techniques by creating a more physiological geometry and minimizing stenotic angles of the graft can provide the extra-anatomic ilio-femoral crossover bypass with long-lasting durability. This may increase the frequency of indications for using ilio-femoral crossover bypasses

Resection of a juxtarenal aneurysm complicated by rupture. Clinical case

Caz clinic. Se prezintă un caz clinic de tratament chirurgical soldat cu succes al unui anevrism de aortă juxtarenal complicat cu ruptură al unui pacient de 76 ani. Boala a debutat de 3 zile cu dureri puternice în regiunea lombară, cu iradiere în abdomen. Internat în spitalul orășenesc, unde la CT angiografie s-a depistat un anevrism al aortei abdominale complicat cu ruptură in spațiul retroperitoneal. Pacientul a fost transferat în SCR ,,T. Moșneaga” operat în mod urgent. La laparotomie xifopubiană s-a depistat circa un litru de lichid sero-sangvinolent, anevrism juxtarenal cu hematom retroperitoneal. După clamparea aortei suprarenale s-a efectuat rezecția anevrismului rupt, cu protezare aorto-femurală pe dreapta și iliacă pe stânga. Perioada postoperatorie fără complicații. Externat la a 11-a zi în stare satisfăcătoare. CT angiografie de control peste 6 luni- proteza aortală funcțională, fără alte patologii. Concluzie. În cazul anevrismelor aortei abdominale complicate cu ruptură, care nu pot fi rezolvate endovascular din diferite motive (anatomie nepotrivită, lipsa utilajului necesar la moment etc) este necesar tratamentul chirurgical deschis în mod urgent. Posedarea metodelor deschise nu trebuie exclusă din arsenalul chirurgului vascular.Clinical case. We present a clinical case of a successful surgical treatment of a ruptured juxtarenal aortic aneurysm in a 76-year-old patient. The disease started three days ago with severe pain in the lower back, radiating to the abdomen. The patient was transferred to the local hospital, where a CT angiography revealed an abdominal aortic aneurysm complicated by retroperitoneal rupture. The patient was urgently transferred to the "T. Moșneaga'' Intensive Care Unit for surgery. Xipho-pubic laparotomy revealed approximately one liter of serosanguinous fluid, a juxtarenal aneurysm with a retroperitoneal hematoma. After clamping the suprarenal aorta, resection of the ruptured aneurysm was performed, followed by aortic-femoral grafting on the right side and iliac grafting on the left side. The postoperative period was uneventful. The patient was discharged in satisfactory condition on the 11th day. A follow-up CT angiography after 6 months showed a functional aortic graft without any other pathologies. Conclusions. In cases of abdominal aortic aneurysms complicated by rupture, which cannot be resolved endovascularly due to various reasons (inappropriate anatomy, lack of necessary equipment at the moment, etc.), urgent open surgical treatment is necessary. Proficiency in open surgical techniques should not be excluded from the vascular surgeon's armamentarium

Pathological elongation of the internal carotid artery: surgical treatment and immediate postoperative results

Scopul lucrării. În structura cauzelor dezvoltării insuficienței cerebrovasculare, elongarea patologică a arterei carotide interne ocupă locul 2, după afectarea aterosclerotică. Prevalența dolicoarteriopatiei la populația generală se estimează a fi de la 10 la 40 %, iar de la 16% până la 56 % din pacienți au în anamnestic deficit neurologic tranzitor sau permanent. Scopul lucrării este optimizarea tehnicilor chirurgicale și aprecierea eficienței postoperatorii imediate la pacienții cu elongare patologică a arterei carotide interne. Materiale și metode. Studiul efectuat reprezintă o analiză retrospectivă a 243 pacienți, tratați în cadrul IMSP SCR ,,Timofei Moșneaga”, secția de Chirurgie Vasculară în perioada 2002-2022. Rezultate. La pacienții supuși studiului s-a efectuat 258 intervenții chirurgicale. Rezultatele imediate au fost: la 230 pacienți (89.14 %) a dispărut simptomatologia preoperatorie, AVC ischemic s-a înregistrat la 1 pacient, sindrom coronarian acut sau deces nu s-a înregistrat la nici un pacient din lotul studiat. Concluzii. Luând în considerare rata mică de complicații periprocedurale precum și eficacitatea postoperatorie imediată evidentă, putem spune că intervenția chirurgicală în tratamentul elongărilor patologice ale arterelor carotide interne reprezintă o metoda sigură și eficientă pentru prevenirea accidentelor vasculare cerebrale acute și îmbunătățirea calității vieții pacienților.Aim of study. Among the causes contributing to the development of cerebrovascular insufficiency, pathological elongation of the internal carotid artery ranks second after atherosclerotic involvement. The prevalence of dolichoarteriopathy in the general population is estimated to range from 10% to 40%, and between 16% and 56% of patients have a history of transient or permanent neurological deficits. The aim of this study was to optimize surgical techniques and assess immediate postoperative efficacy in patients with pathological elongation of the internal carotid artery. Materials and methods. This study represents a retrospective analysis of 243 patients treated at the State Medical and Pharmaceutical University "Timofei Moșneaga", Department of Vascular Surgery, between 2002 and 2022. Results. A total of 258 surgical interventions were performed in the study group. The immediate results were as follows: symptomatology disappeared in 230 patients (89.14%), one patient experienced an ischemic stroke, and no cases of acute coronary syndrome or death were recorded among the studied patients. Conclusions. Considering the low rate of periprocedural complications and the evident immediate postoperative effectiveness, it can be concluded that surgical intervention for the treatment of pathological elongation of the internal carotid artery is a safe and efficient method for preventing acute cerebrovascular accidents and improving the quality of life for patients

Evidence of West Nile virus (WNV) circulation in wild birds and WNV RNA negativity in mosquitoes of the Danube Delta Biosphere Reserve, Romania, 2016

West Nile virus (WNV) is a zoonotic flavivirus whose transmission cycle in nature includes wild birds as amplifying hosts and ornithophilic mosquito vectors. Bridge vectors can transmit WNV to mammal species potentially causing West Nile Fever. Wild bird migration is a mode of WNV introduction into new areas. The Danube Delta Biosphere Reserve (DDBR) is a major stopover of wild birds migrating between Europe and Africa. The aim of this study was to investigate the presence of WNV in the DDBR during the 2016 transmission season in wild birds and mosquitoes. Blood from 68 wild birds (nine different species) trapped at four different locations was analyzed by competitive ELISA and Virus Neutralization Test (VNT), revealing positive results in 8/68 (11.8%) of the wild birds by ELISA of which six samples (three from juvenile birds) were confirmed seropositive by VNT. Mosquitoes (n = 6523, 5 genera) were trapped with CDC Mini Light traps at two locations and in one location resting mosquitoes were caught. The presence of WNV RNA was tested in 134 pools by reverse transcription quantitative PCR (RT-qPCR). None of the pools was positive for WNV-specific RNA. Based on the obtained results, WNV was circulating in the DDBR during 2016

A Machine Learning Trainable Model to Assess the Accuracy of Probabilistic Record Linkage

Record linkage (RL) is the process of identifying and linking data that relates to the same physical entity across multiple heterogeneous data sources. Deterministic linkage methods rely on the presence of common uniquely identifying attributes across all sources while probabilistic approaches use non-unique attributes and calculates similarity indexes for pair wise comparisons. A key component of record linkage is accuracy assessment — the process of manually verifying and validating matched pairs to further refine linkage parameters and increase its overall effectiveness. This process however is time-consuming and impractical when applied to large administrative data sources where millions of records must be linked. Additionally, it is potentially biased as the gold standard used is often the reviewer’s intuition. In this paper, we present an approach for assessing and refining the accuracy of probabilistic linkage based on different supervised machine learning methods (decision trees, naïve Bayes, logistic regression, random forest, linear support vector machines and gradient boosted trees). We used data sets extracted from huge Brazilian socioeconomic and public health care data sources. These models were evaluated using receiver operating characteristic plots, sensitivity, specificity and positive predictive values collected from a 10-fold cross-validation method. Results show that logistic regression outperforms other classifiers and enables the creation of a generalized, very accurate model to validate linkage results

Insights from the NeurIPS 2021 NetHack Challenge

In this report, we summarize the takeaways from the first NeurIPS 2021 NetHack Challenge. Participants were tasked with developing a program or agent that can win (i.e., ‘ascend’ in) the popular dungeon-crawler game of NetHack by interacting with the NetHack Learning Environment (NLE), a scalable, procedurally generated, and challenging Gym environment for reinforcement learning (RL). The challenge showcased community-driven progress in AI with many diverse approaches significantly beating the previously best results on NetHack. Furthermore, it served as a direct comparison between neural (e.g., deep RL) and symbolic AI, as well as hybrid systems, demonstrating that on NetHack symbolic bots currently outperform deep RL by a large margin. Lastly, no agent got close to winning the game, illustrating NetHack’s suitability as a long-term benchmark for AI research

Carotid-brachial bypass in severe upper limb ischemia

Scopul lucrării. În ocluziile axului arterial subclavio-axilar cu ischemie severă a membrului superior s-ar impune folosirea metodelor endovasculare sau aplicarea unui bypass ortotop. În cazul imposibilității din motive tehnice sau stării pacientului drept alternativă servește bypass-ul carotido-brahial. Scopul studiului este aprecierea posibilității utilizării bypass-ului extraanatomic carotido-brahial în revascularizarea membrului superior în ischemia severă. Materiale și metode. Studiul cuprinde 5 pacienți cu ocluzia axului subclavio-axilar cu ischemie severă a membrului superior, dintre care 3 cu ocluzie acută pe fondal de stenoze aterosclerotice, la care intervenția inițială de trombectomie (embolectomie) a eșuat, un pacient cu tromboza anevrismului a. subclaviculare și un pacient cu ocluzie aterosclerotică de gradul IV cu gangrena degetului II, la care intervenția endovasculară a eșuat. La toți pacienții s-a aplicat un bypass carotido-brahial cu grefon safen intern inversat. Grefele au fost amplasate suprafascial supraclavicular. Rezultate. La toți 5 pacienți ischemia a cedat complet. La 4 din ei s-a restabilit pulsul distal. La pacientul cu ateroscleroză cronică de gradul IV, cu afectarea concomitentă a arterelor antebrațului, pulsul s-a restabilit la bifurcația arterei brahiale. La acest pacient s-a efectuat amputația degetului. Complicații nu s-au înregistrat. Incomodități subiective din cauza amplasării suprafasciale și supraclaviculare a bypass-urilor deasemenea n-au fost înregistrate. Concluzii. Bypass-urile carotido-brahiale localizate suprafascial și supraclavicular servesc o alternativă a bypass-urilor ortotope inclusiv în cazurile eșecurilor sau contraindicațiilor metodelor endovasculare.Aim of study. In cases of occlusion of the subclavian-axillary arterial axis with severe upper limb ischemia, the use of endovascular methods or the application of an orthotopic bypass may be necessary. In case of technical impossibility or patient condition, carotidbrachial bypass serves as an alternative. The objective of the study is to evaluate the possibility of using extra-anatomic carotidbrachial bypass for revascularization of the upper limb in severe ischemia Materials and methods. The study includes 5 patients with occlusion of the subclavian-axillary axis and severe upper limb ischemia, of which 3 had acute occlusion due to atherosclerotic stenosis, with initial thrombectomy (embolectomy) being unsuccessful. One patient had subclavian artery aneurysm thrombosis, and one patient had grade IV atherosclerotic occlusion with gangrene of the second digit, in whom endovascular intervention was unsuccessful. Carotid-brachial bypass with an inverted internal saphenous vein graft was performed in all patients. The grafts were placed in a suprafascial supraclavicular position. Results. Complete resolution of ischemia was achieved in all 5 patients. Distal pulses were restored in 4 of them. In the patient with chronic grade IV atherosclerosis and concomitant involvement of the forearm arteries, the pulse was restored at the brachial artery bifurcation. Digit amputation was performed in this patient. No complications were recorded, and there were no subjective discomforts related to the suprafascial and supraclavicular placement of the bypasses. Conclusions. Suprafascial and supraclavicular carotid-brachial bypasses serve as an alternative to orthotopic bypasses, including in cases of failure or contraindications to endovascular methods