1,938 research outputs found
Dozens of virtual impactor orbits eliminated by the EURONEAR VIMP DECam data mining project
Massive data mining of image archives observed with large etendue facilities
represents a great opportunity for orbital amelioration of poorly known virtual
impactor asteroids (VIs). There are more than 1000 VIs known today; most of
them have very short observed arcs and many are considered lost as they became
extremely faint soon after discovery. We aim to improve the orbits of VIs and
eliminate their status by data mining the existing image archives. Within the
European Near Earth Asteroids Research (EURONEAR) project, we developed the
Virtual Impactor search using Mega-Precovery (VIMP) software endowed with a
very effective (fast and accurate) algorithm to predict apparitions of
candidate pairs for subsequent guided human search. Considering a simple
geometric model, the VIMP algorithm searches for any possible intersection in
space and time between the positional uncertainty of any VI and the bounding
sky projection of any image archive. We applied VIMP to mine the data of 451914
Blanco/DECam images observed between 12 Sep 2012 and 11 Jul 2019, identifying
212 VIs that possibly fall into 1286 candidate images leading to either
precovery or recovery events. Following a careful search of candidate images,
we recovered and measured 54 VIs in 183 DECam images. About 4000 impact orbits
were eliminated from both lists, 27 VIs were removed from at least one list,
while 14 objects were eliminated from both lists. The faintest detections were
around V~24.0, while the majority fall between 21<V<23. The minimal orbital
intersection distances remains constant for 67% detections, increasing for
eight objects and decreasing for 10 objects. Most eliminated VIs had short
initial arcs of less than 5 days. Some unexpected photometric discovery has
emerged regarding the rotation period of 2018 DB, based on the close inspection
of longer trailed VIs and the measurement of their fluxes along the trails.Comment: Accepted for publication in Astronomy & Astrophysics (27 July 2020
More Than 1700 Years of Word Equations
Geometry and Diophantine equations have been ever-present in mathematics.
Diophantus of Alexandria was born in the 3rd century (as far as we know), but a
systematic mathematical study of word equations began only in the 20th century.
So, the title of the present article does not seem to be justified at all.
However, a linear Diophantine equation can be viewed as a special case of a
system of word equations over a unary alphabet, and, more importantly, a word
equation can be viewed as a special case of a Diophantine equation. Hence, the
problem WordEquations: "Is a given word equation solvable?" is intimately
related to Hilbert's 10th problem on the solvability of Diophantine equations.
This became clear to the Russian school of mathematics at the latest in the mid
1960s, after which a systematic study of that relation began.
Here, we review some recent developments which led to an amazingly simple
decision procedure for WordEquations, and to the description of the set of all
solutions as an EDT0L language.Comment: The paper will appear as an invited address in the LNCS proceedings
of CAI 2015, Stuttgart, Germany, September 1 - 4, 201
Computing with cells: membrane systems - some complexity issues.
Membrane computing is a branch of natural computing which abstracts computing models from the structure and the functioning of the living cell. The main ingredients of membrane systems, called P systems, are (i) the membrane structure, which consists of a hierarchical arrangements of membranes which delimit compartments where (ii) multisets of symbols, called objects, evolve according to (iii) sets of rules which are localised and associated with compartments. By using the rules in a nondeterministic/deterministic maximally parallel manner, transitions between the system configurations can be obtained. A sequence of transitions is a computation of how the system is evolving. Various ways of controlling the transfer of objects from one membrane to another and applying the rules, as well as possibilities to dissolve, divide or create membranes have been studied. Membrane systems have a great potential for implementing massively concurrent systems in an efficient way that would allow us to solve currently intractable problems once future biotechnology gives way to a practical bio-realization. In this paper we survey some interesting and fundamental complexity issues such as universality vs. nonuniversality, determinism vs. nondeterminism, membrane and alphabet size hierarchies, characterizations of context-sensitive languages and other language classes and various notions of parallelism
Méthodes de remaillage parallèle pour le calcul intensif de structures industrielles
International audienceCe travail aborde la problématique de l'adaptation de maillage parallèle au cours de calculs de structures par éléments finis résolus par des méthodes de décomposition de domaine sans recou-vrement. L'objectif est de disposer d'algorithmes permettant d'orchestrer efficacement des phases de remaillage séquentiel appliquées à des sous-domaines distincts dans un contexte distribué, en restant au-tant que possible agnostique aux outils et bibliothèques logicielles sous-jacents. Deux algorithmes sont présentés et leurs performances illustrées sur la base d'un cas métier à géométrie simplifiée
Механизмы внутристентового рестеноза анализируемые путём коронарной ангиографии и внутрикоронарной ультрасонографии
Although the coronary angiography remains a proven method of in-stent restenosis assessment, intracoronary ultrasound (IVUS) is underlined as
a method of better coronary lesion indices evaluation. This study was aimed as an attempt at relevant in-stent restenosis mechanisms estimation via
concomitant using of IVUS and coronary angiography. These exams were applied to 47 patients having 54 bare metallic and eluting stents. Obtained
results indicated different mechanisms of restenosis development in bare metallic and eluting stents. The neointima hyperplasia and negative artery
remodeling in metallic stent restenosis are more expressed. Likewise, the IVUS method appears as a feasible tool of the coronary plaque area determination
and guiding of stent implantation during angioplasty. The last aspect is especially important in the case of coronary artery diameter less than 3 mm.Хотя коронарная ангиография продолжает оставаться апробированным методом выявления внутристентового рестеноза, внутрикоронарная
ультрасонография (IVUS) выделяется как метод лучшего определения показателей коронарных поражений. С целью анализа механизмов
развития рестеноза эти два метода были использованы на 47 больных, имеющих 54 имплантированных металлических и фармакологических
стентов. Полученные данные показывают наличие различных механизмов развития рестеноза металлических и фармакологических стентов.
Гиперплазия неоинтимы и негативное ремоделирование артерии более выражены в металлических стентах. Метод IVUS представляется
достоверным способом определения размеров коронарной бляшки и контроля имплантации стента, особенно, когда диаметр коронарной
артерии меньше 3 мм
The options for diagnosis and treatment of occlusive colon tumors
Clinica Chirurgie ”Sf.Arhanghel Mihail”, Catedra chirurgie nr.1 ”N.Anestiadi”, USMF “Nicolae Testemițanu”, Chișinău,
Republica Moldova, Al XII-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova cu participare internațională 23-25 septembrie 2015Introducere: Ocluzia intestinală acută (OIA) reprezintă manifestarea clinică tardivă a cancerului de colon. Necesitatea stabilirii
diagnosticului preoperator este discutabilă.
Material și metode: Studiul retrospectiv a cuprins 156 pacienți cu tumori colonice spitalizați în perioada 1998-2015. Bărbați –
67, de sex femenin – 89. A dominat vîrsta peste 60 de ani în mai mult de 60%. Manifestările clinice (dureri, vome, absența
tranzitului intestinal, balonare) și paraclinice – radiografia abdomenului pe gol cu nivele hidroaerice, au dedus sindromul de OIA
în 60 cazuri. Irigoscopia – bloc intestinal (38 cazuri) și fibrocolonoscopia (21 cazuri) orientează diagnosticul etiologic în alte 59
cazuri. Indicațiile operatorii: pentru OIA cînd durerile și distensia se accentuează după tratamentul de reechilibrare și aspirație
nazogastrică au fost operați 36 pacienți; pentru OIA și tumoare abdominală palpabilă plus semne peritoneale și leucocitoză s-a
intervenit în 11 cazuri; OIA cu nivel hidroaeric mai mare de 10 cm, distensia accentuată și pericolul de perforație diastatică de
cec a impus intervenția în 13 cazuri. Aceste situații au dictat și rapiditatea intervenției operatorii – 39 pacienți au fost operați în
primele 24 ore; 21 cazuri – în 24-48 ore; iar în peste 48 ore – 59 bolnavi.
Rezultate: Operații radicale s-au efectuat în 108 cazuri (90,7%), cu restabilirea primară a tranzitului – în 55 cazuri (51%).
Mortalitatea postoperatorie – 18 cazuri (15,1%). Histopatologic: adenocarcinom – în 16 cazuri cu metastaze la distanță, inclusiv
canceromatoză – 6 cazuri. Neoperați – 37 cazuri.
Concluzii: Indicațiile pentru tratamentul chirurgical de urgență în ocluziile intestinale acute continue să persiste în arsenalul
terapeutic, chiar și în condițiile unui diagnostic neelucidat preoperator. Depistarea intraoperatorie a cancerului ocluziv impune
înlăturarea acestuia, restabilirea tractului digestiv reieșind din condițiile locale și generale.Introduction: Acute intestinal obstruction (AIO) of the colon represents a late clinic of the colon cancer. The need for the
preoperative diagnosis is questionable.
Material and methods: The retrospective study included 156 patients, 67 – men and 89 – women with colon tumors,
hospitalized in the period of 1998-2015. In more than 60% of the cases the patients were aged over 60 years. The clinical
manifestations (pain, vomiting, lack of bowel movements, bloating) and the paraclinic ones – the empty stomach radiography
with air-liquid levels deduced AIO syndrome in 60 cases. The barium enema – intestinal obstruction (38 cases) and
fibrocolonoscopy (21 cases) orients the etiologic diagnosis in other 59 cases. Operative indications: for AIO when the pain and
the distension increase after the rebalancing treatment and nasogastric suction – 36 cases were operated; for AIO and palpable
tumor as well as peritoneal signs and leukocytosis – 11 cases were operated; for AIO with air-liquid levels bigger than 10 cm,
the emphasized distension and persisting danger of diastatic perforation of the caecum – required interventions in 13 cases.
These situations have imposed the rapidity of the surgical intervention: 39 patients were operated within the first 24 hours; 21
cases – within 24-48 hours; and 59 patients – after more than 48 hours.
Results: Radical operations were carried out in 108 cases (90.7%) with the primary restoration of the transit in 55 cases (51%).
Postoperative mortality – 18 cases (15.1%). Histologic result: adenocarcinoma – in 16 cases with the remote metastasis,
including canceromatosis – in 6 cases. There were 37 inoperable cases.
Conclusions: The indications for emergency surgical treatment of acute intestinal occlusions continue to persist in the
therapeutic arsenal, even in cases of unclear preoperative diagnosis. The intraoperative detection of occlusive cancer requires
its removal, and the restoring of the digestive tract based on the local and general conditions
Prototype tests for the ALICE TRD
A Transition Radiation Detector (TRD) has been designed to improve the
electron identification and trigger capability of the ALICE experiment at the
Large Hadron Collider (LHC) at CERN. We present results from tests of a
prototype of the TRD concerning pion rejection for different methods of
analysis over a momentum range from 0.7 to 2 GeV/c. We investigate the
performance of different radiator types, composed of foils, fibres and foams.Comment: Presented at the IEEE Nuclear Science Symposium and Medical Imaging
Conference, Lyon, October 15-20, 2000 (accepted for publication in IEEE TNS),
Latex (IEEEtran.cls), 7 pages, 11 eps figure
Multiple current sheets in a double auroral oval observed from the MAGION-2 and MAGION-3 satellites
Aspects of the population morbidity in some regions of the Republic of Moldova
General Hygiene Department, Nicolae Testemitsanu State University of Medicine and Pharmacy, National Centre of Public Health, Chisinau, the Republic of MoldovaBackground: The health of the Moldovan population requires special attention, due to direct and indirect biological, environmental, behavioural and health factors. Material and methods: We studied population morbidity from the following localities: town Cupcini, village Bratuseni, village Ruseni (Edinet district); town Vadul lui Voda, town Cricova, village Condrita (municipality Chisinău); village Rosu, village Moscovei, village Huluboaia (Cahul district). Statistical data were taken from the statistical report No 12, for the period from 2012 to 2014. Results: Morbidity analysis showed that the overall prevalence of increased average values was recorded in the village Bratuseni, Edinet district – 16119.0±247.70/000. In town Vadul lui Voda, Cricova, village Condriţa (municipality Chisinau), overall prevalence values ranged within 6967.0±813.0 – 8721.3±375.90/000. Meanwhile, village Rosu, village Moscovei, village Huluboaia (Cahul district), mean values of overall prevalence were included within 2379.8±574.8 and 3219.8±152.70/000. Analysis of the general incidence emphasized that the community in the North recorded mean values within 1370.5±0.7 – 11162.4±190.40/000, localities in the center and south - 1877.8±246.3 – 3149.0±187.80/000 and respectively 899.3±95.0 – 1244.8±339.80/000. Conclusions: Population morbidity was growing during 2012-2014. Prevalence of diseases of the circulatory, digestive and urogenital systems was higher in central areas and the osteoarticular system diseases – in northern communities. The incidence of cardiovascular, urogenital and osteoarticular diseases was higher in cities from North, and digestive system diseases – in central areas
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