Cortical feedback loops bind distributed representations of working memory

Working memory—the brain’s ability to internalize information and use it flexibly to guide behaviour—is an essential component of cognition. Although activity related to working memory has been observed in several brain regions, how neural populations actually represent working memory and the mechanisms by which this activity is maintained remain unclear. Here we describe the neural implementation of visual working memory in mice alternating between a delayed non-match-to-sample task and a simple discrimination task that does not require working memory but has identical stimulus, movement and reward statistics. Transient optogenetic inactivations revealed that distributed areas of the neocortex were required selectively for the maintenance of working memory. Population activity in visual area AM and premotor area M2 during the delay period was dominated by orderly low-dimensional dynamics that were, however, independent of working memory. Instead, working memory representations were embedded in high-dimensional population activity, present in both cortical areas, persisted throughout the inter-stimulus delay period, and predicted behavioural responses during the working memory task. To test whether the distributed nature of working memory was dependent on reciprocal interactions between cortical regions, we silenced one cortical area (AM or M2) while recording the feedback it received from the other. Transient inactivation of either area led to the selective disruption of inter-areal communication of working memory. Therefore, reciprocally interconnected cortical areas maintain bound high-dimensional representations of working memory

КОСМОГОНІЧНІ МІФИ ДАВНІХ СКАНДИНАВІВ І СЛОВЯН: СПІЛЬНЕ І ВІДМІННЕ

У цій статті показані спільні і відміні риси у космогонічних міфах давніх скандинавів і слов’ян. У статті показано тих, хто виступав творцями світу в міфології давніх скандинавів і слов’ян. Показано місце, де відбувався процес творення, а також спосіб, який був використаний творцями (In this article showing common features and the abolition of cosmogonic myths of the ancient Scandinavians and Slavs. The article depicts those who were the creators of the world in the mythology of the ancient Scandinavians and Slavs. A place, where the process of creation took place and also the method that was used by creators

First experience in off pump coronary artery bypass grafting of anterior descending artery via inferior mini-sternotomy

Spitalul Internaţional “Medpark”, Chişinău, Republica Moldova, Al XII-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova cu participare internațională 23-25 septembrie 2015Introducere: În prezent pontajul coronarian pe o singură arteră reprezintă o raritate. Cardiologia intervenţională rezolvă marea majoritate a cazurilor cu afectarea patului coronarian cu o singură limitare – afectarea ostială a arterei descendente anterioare (ADA). Pentru pontajul coronarian pe cord bătând (CB): artera toracică internă stângă (ATIS) anastomozată cu ADA, este cunoscut abordul toracic miniminvaziv. Acestui abord îi sunt valabile şi unele exigenţe deosebite: set de ustensile adaptate special pentru minitoracotomie, echipă polidisciplinară bine formată şi, desigur, experienţa chirurgului operator. O problemă actuală, pentru perioada postoperatorie, rămâne combaterea durerii postoperatorii. Scopul lucrării a fost implementarea abordului mini-invaziv în operaţiile pe CB. Material şi metode: Pe parcursul ultimilor 5 ani, operaţi pe CB prin sternotomie inferioară au fost 13 pacienţi (5 femei, 8 bărbaţi), vîrsta medie – 59,3 ani. Toţi pacienţii au prezentat o afectare monovasculară severă pe ADA, segmentul I ostial. Stabilizarea cordului și a arterei – efectuată cu ajutorul dispozitivului “Octopus 4”. Anastomoza ATIS-ADA – efectuată cu sutură Prolene 8/0. Rezultate: Perioada postoperatorie complicată cu hemoragie – 1 pacient, menajată conservativ. Durata medie a spitalizării a constituit 4,5 zile. În perioada precoce şi de lunga durată accese anginoase nu s-au înregistrat. Concluzii: Mini-sternotomia inferioară reprezintă un abord optim către ADA, cu expoziţie suficientă pentru prelevarea ATIS. Sindromul algic postoperator este minim, reconvalescenţa fizică este rapidă, amplituda mişcărilor în membre superioare – nelimitată.Introduction: Nowadays, a single artery bypass surgery is a rarity. Interventional cardiology solves most cases of affected coronary arteries, with a single limitation – ostial involvement of anterior descending coronary artery (ADCA). For beating-heart coronary bypass (BHCB): left internal thoracic artery (LITA) anastomosis with anterior descending artery is well known minimally invasive thoracic approach. But for this approach several special requirements should be met: set of tools specially adapted for mini-thoracotomy, well trained multidisciplinary team and the experience of surgeon. A current problem is combating of the postoperative pain. Aim of the study was the implementation of minimally invasive access in BHCB. Material and methods: During the last five years, 13 patients (5 women, 8 men) with mean age – 59.3 years were operated with BHCB. All patients presented a severe single vessel injury of ADCA in I ostial segment. Stabilization of the heart and artery was carried out with the device Octopus 4. The anastomosis between LITA-ADCA was performed with the Prolene 8/0 suture. Results: The postoperative period was complicated with hemorrhage in 1 patient, treated conservatively. The mean duration of hospitalization was 4.5 days. In early and long-term postoperative period relapses of heart angina were not registered. Conclusion: Lower mini-sternotomy is an optimal approach to ADCA, with sufficient exposition for harvesting LITA. Postoperative pain syndrome is minimal, physical recovering is fast, the amplitude of movements in upper limbs is unrestricted

Operaţiile plastice în corecţia valvulopatiilor mitrale

Intervenţiile reconstructive pe valva mitrală înregistrează o creştere tot mai rapidă. Răspândirea acestor operaţii a fost impulsionată de imperfecţiunile protezelor valvulare. Prioritatea plastiei mitrale faţă de protezare este evidentă. Ea asigură un prognostic favorabil de supravieţuire, permite păstrarea funcţiei contractile a ventriculului stâng, reduce complicaţiile infecţioase şi tromboembolice, se mic- şorează frecvenţa hemoragiilor în urma administrării anticoagulantelor. În acest studiu analizăm prima noastră experienţă de reconstrucţie a valvei mitrale la 66 de pacienţi. Au fost studiate cauzele apariţiei patologiei valvulare, tehnicile chirurgicale aplicate, precum şi rezultatele postoperatorii precoce şi tardive. În concluzie, menţionăm că efectuarea operaţiilor plastice impune, în primul rând, depistarea într-un stadiu precoce a afectării valvulare, până la instalarea modifi cărilor anatomice semnifi cative. Rezultatele precoce şi tardive obţinute sunt foarte bune, cea ce permite să extindem indicaţiile pentru operaţiile reconstructive pe valva mitrală

Конкурентоспособности продукции украинских предприятий в условиях глобализации мировой экономики

Дана стаття присвячена висвітленню питання конкурентоспроможності продукції з огляду на все більшу глобалізацію світової економіки. Розглянуто факторіальну оцінку конкурентоспроможності підприємства та запропоновано метод її підрахунку. Визначено методику розрахунку конкурентоспроможності продукції та окреслено головні етапи найбільш дієвого з них – методу відносних показників.This article is about competitiveness, it takes into account the increase in the globalization of the world economy. Here we examined the factorial assessment of the competitiveness of enterprises and offered the method of calculation of competitiveness. We determined the methodology for calculating the competitiveness of products and specify the main stages of the most effective of them – the method of the relative performance.Данная статья освещает вопросы конкурентоспособности продукции с учетом все большей глобализации мировой экономики. Рассмотрена факториальная оценка конкурентоспособности предприятия и предложен метод ее подсчета. Определена методика расчета конкурентоспособности продукции и намечены основные этапы наиболее действенного из них – метода относительных показателей

Реакторы с микротвэлами: гидродинамика проницаемых каналов насыпной сборки

The prospect of use of fuel in the form of micro particles (balls with a diameter about a millimeter formed by the fissile material and a protective cover to hold the radioactive fission products) in nuclear reactors is disclosed. It’s marked that flow ability, large specific surface of heat removal, extraordinary high resistance of micro fuel particles allow to design innovative safe reactors for various purpose: transportable, breeders, high-temperature, high neutron flux etc. It’s suggested to complete the active zone by bulk heat releasing assemblies. In them the advantages of spherical micro fuel particles and a coolant side supply to the bed through permeable distribution and branch channels are harmoniously combined in these assembles. It is presented the scheme of bulk assemblies and carried out the analysis of modeling of dynamics of a stream in permeable channels. It is shown that the mathematical description of liquid movement in such channels has ambiguity and discrepancy. To eliminate modeling shortcomings a new kinematic image of current in the permeable channels was offered. It was proposed instead of the existing one representing a jet to which particles of coolant were continuously joined or separated on the permeable wall. In the new interpretation the flow in the permeable channel is considered as turn of the stream at its simultaneous expansion or narrowing depending on there is outflow or inflow. On the base of this image the equation for determination of coolant pressure changing in the permeable channel is obtained; reaction of a stream for changing of flow rate increment is established, the tangent component of a velocity on a permeable wall is founded. Thereby the disadvantages of describing of coolant moving in the bulk assembles channels are eliminated. Permeable channels are used not only in nuclear reactors, but also in many other technological devices: catalytic reactors, heat exchangers, filters, collector and distributing systems. The obtained results can be used for designing other devices with permeable channels.Раскрыта перспектива использования в ядерных реакторах топлива в виде микротвэлов – шариков из делящегося материала диаметром порядка миллиметра, покрытых защитной оболочкой для удержания радиоактивных продуктов деления. Отмечено, что сыпучесть, большая удельная поверхность теплосъема, необычайно высокая стойкость микротвэлов позволяют на их базе проектировать инновационные безопасные реакторы различного целевого назначения (транспортабельные, бридеры, высокотемпературные, высокопоточные и т. д.). Предложена комплектация активной зоны реактора с насыпными тепловыделяющими сборками. В них гармонично сочетаются достоинства микротвэлов с преимуществами бокового подвода теплоносителя к топливному слою с помощью проницаемых распределительного и отводного каналов. Представлена схема насыпной сборки и проведен анализ моделирования динамики потока в проницаемых каналах. Показано, что существующее математическое описание движения теплоносителя в них отличается неоднозначностью и противоречивостью. Для устранения недостатков в моделировании построен новый кинематический образ течения в проницаемом канале взамен существующего, представляющего собой струю, к которой на проницаемой стенке непрерывно присоединяются или отделяются от нее частицы теплоносителя. Движение в проницаемом канале в новой трактовке рассматривается как поворот потока при одновременном его расширении или сужении в зависимости от того, происходит в канале отток или приток. На основании такого представления получено уравнение изменения давления теплоносителя в проницаемом канале, определена реакция потока на приращение расхода, описана величина касательной составляющей вектора скорости на проницаемой стенке, тем самым устранены недостатки описания движения теплоносителя в каналах насыпной сборки. Полученные результаты могут также использоваться при проектировании других технических устройств, содержащих проницаемые каналы

Consideration of uncertainty of information on load and generation values under daily reconfiguration of primary distribution network

Intelligent electric networks make it possible to remotely control switchings, thus preventing overloads and enhancing reliability of power supply to consumers. In the paper, the daily reconfiguration of a primary distribution network is considered as a means to reduce energy losses in the network. An algorithm applied for the reconfiguration is based on the methods of the theory of graphs and includes a high-speed program for load flow calculation. The research is focused on the impact of renewable generation and active demand with loads changing depending on daily variation in electricity price on the reduction in losses at reconfiguration. An algorithm is proposed to optimize load curves of load-controlled consumers. The calculation of probabilistic load flows is applied to assess the impact of the uncertainty of nodal power forecast on energy loss reduction at reconfiguration. The results of the research demonstrate the effectiveness of the proposed approaches, and are illustrated by a 33-node test distribution network

Papillary muscle sling as an adjunctive procedure for surgical left ventricular remodeling

IMSP, SCR, departamentul cardiochirurgie, Al XI-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova și cea de-a XXXIII-a Reuniune a Chirurgilor din Moldova „Iacomi-Răzeșu” 27-30 septembrie 2011Introducere: Remodelarea ventriculului stâng folosind metoda de aproximare a muşchilor papilari după tehnica Hvass ar putea crea o posibilitate de îmbunătățire a competenței valvei mitrale. Materiale şi metode: în studiu au fost incluşi 39 de pacienți la care a fost efectuată remodelarea ventriculului stâng după tehnica Hvass şi un caz de aproximare a muşchilor papilari a ventriculului drept. Vârsta medie a pacienților a fost de 54 ± 8 (39 - 66) ani; 35 de bărbați şi 5 femei. 33 de pacienți cu cardiopatie ishemică şi anevrism de ventricul stâng şi 7 pacienți cu valvulopatii de etiologie diversă. Toți pacienții cu insuficiență cardiacă NYHA III-IV, hipertensiune pulmonară (PSAP 50-70 mmHg), insuficiență mitrală gr.II-IV şi dilatarea inelului fibros a valvei mitrale (38-46 mm), distanța dintre muşchii papilari mai mare de 2,5 cm. Pentru aproximarea pilierilor la 31 (77,5%) s-a folosit o bucată de proteză vasculară Gor-Tex 4-0, la 6 (15%) pacienți s-a utilizat un segment din proteză vasculară Dacron şi la 3 (7,5%) pacienți s-a folosit segmente din venă autologă. Rezultate: În toate cazurile fracția de ejecție a crescut de la 39 ± 8% până la 49 ± 5% după intervenția chirurgicală. Volumul diastolic a ventriculului stâng a scăzut de la 254 ± 81 ml până la intervenție la 173 ± 40 ml după intervenție. S-a obținut o regresie a insuficienței valvei mitrale până la gradul I-II şi micşorarea diametrului inelului fibros până la 28,6 mm. După remodelarea ventriculului drept dimensiunea cavității a scăzut de la 40 mm la 28 mm. De asemenea, s-a practicat anuloplastia, care a asigurat competență completă a valvei tricuspide. Concluzii: Aproximarea muşchilor papilari (tehnica Hvass) pentru remodelarea ventricului stâng oferă beneficii prin scăderea volumului diastolic, îmbunătățirea considerabilă a coaptării valvei mitrale şi regresia insuficienței mitrale cu creşterea fracției de ejecție a ventriculului stâng.Introduction: Remodeling of left ventricle using papillary muscle approximation technique could create a possibility of improving mitral valve competence. Methods: We analyzed 40 cases of left ventricular remodeling according to Hvass technique and one case of right ventricle papillary muscle approximation. The average age of patients was 54 ± 8 (39-66) years, 35 men and 5 women. 33 patients had left ventricular aneurism and 7 - valvulopathies of diverse etiology. All the patients had NYHA III-IV, pulmonary hypertension (SPRV 50–70 mmHg), mitral insufficiency (II-IV gr.) and dilated mitral fibrous annulus (38 – 46 mm) and the distance between the papillary muscles more than 2.5 cm.To approximate the papillary muscle 31 (77.5%) had used a piece of Gor-Tex vascular prosthesis 4-0, 6 (15%) patients used a segment of the vascular prosthesis Dacron and 3 (7.5%) patients using autologous vein segments. Results: In all of patients ejection fraction increased from 39 ± 8% till 49 ± 5% after the surgery. Left ventricular diastolic volume decreased from 254 ± 81 ml before the intervention to 173 ± 40 ml after. There was obtained the regression of mitral valve insufficiency up to I – II grade and the decreasing of annulus fibrosis diameter to 28,6 mm. After right ventricular remodeling the cavity size dropped from 40 mm to 28 mm. Also was practiced annuloplasty, which assured complete tricuspid valve competence. Conclusions: Hvass technique with the approximation of papillary muscles for left ventricular remodeling offers benefits by decreasing its diastolic volume, considerable improvement of cooptation and regression of mitral regurgitation with increasing ejection fraction of ventricle

Myocardial revascularization on a beating heart

Department of Cardiac Surgery, Republican Hospital, Chisinau, the Republic of MoldovaBackground: Myocardial revascularization on a beating heart in case of the atherosclerotic affection of the coronory arteries. Material and methods: Retrospective analysis of 372 operations (myocardial revascularization without extracorporeal circulation) performed in 2002 October 2013. Results: In our study most patients were extubated within 24 hours. Mechanical ventilation of the lungs for more than 24 hours was required 11 patients (2.9%). Arrhythmias were 63 (17%) patients (atrial fibrillation – 56, atrial flutter – 7), that required additional administration of antiarrhythmic preparations to restore sinus rhythm, but in 11 cases was performed cardioversion. In the early postoperative period died 3 (0.8%) patients: 1 – acute renal failure, 1 – polyorganic failure, 1 – ventricular fibrillation. Conclusion: Off-pump coronary artery bypass (OPCAB) challenges the conventionalon-pump coronary artery bypass grafting (CABG) as the standardof surgical therapy for coronary disease. Conventional coronary bypass surgery is associated with substantialmorbidity caused by cardiopulmonary bypass. Conventional CABG has been performed with reproducible success, but complications cause significant morbidity and mortality. Some complications may be secondary to cardiopulmonary bypass (CPB) and include neurological dysfunction and a systemic inflammatory response syndrome ending in vital organ damage. Although OPCAB on a beating heart is an attractive alternative to conventional CABG on CPB, it also has drawbacks

The surgical tratment of ischemic mitral regurgitation (IMR)

Al XI-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova și cea de-a XXXIII-a Reuniune a Chirurgilor din Moldova „Iacomi-Răzeșu” 27-30 septembrie 2011IMI ca complicație a bolii coronariene este cauzată de o disfuncție papilar-anulară a VS, fapt determinat în stabilirea tacticii de tratament al acestor patologii. Scopul studiului este studierea mecanismului de dezvoltare a IMI, reevaluarea indicațiilor operatorii, aprecierea eficacității şi durabilității tehnicilor chirurgicale efectuate. Material şi metode: În lotul de studiu au fost incluşi 124 pacienți cu IMI, ca consecință a remodelării VS în urma ischemiei, infarctului miocardic suportat.În toate cazurile a fost efectuată revascularizarea miocardului. Simultan la 85 pacienți au suportat tehnici reconstructive pe valva mitrală, la 38 pacienți cu IMI până la gradul II patologia valvulară a fost neglijată.Rezultate: S-a constatat o strănsă legătură a mecanismului de apariție a IMI de localizarea zonelor de infarct miocardic, gradul de afectare a sfericității VS, prevalența dilatării inelului fibros mitral, deplasarea punctului de coaptare valvulară în urma tensionării muşchilor papilari.By- passul coronarian efectuat izolat nu a contribuit la regresia IMI de gardul II, iar în 25% de cazuri în perioada de lungă durată IMI a progresat, menținând o suprasolicitare de volum al VS.În 56 (69,1%) cazuri a fost aplicată o tehnică inovațională de annuloplastie mitrală cu 3 suturi cu o reducere spectaculoasă a gradului de regurgitare mediu de la 2,7±0,5 preoperator la 1,2±0,1 postoperator, asigurând o mobilitate fiziologică a cuspelor valvulare. În paralel, pentru a înlătura cauzele de manifestare a IMI, pacienții au necesitat rezecția aneurismului de VS în 25 (29,4%) cazuri şi aproximarea muşchilor papilari după HVass în 18 (21,2%) cazuri.Toate aceste proceduri au asigurat o restabilire anatomică şi funcțională a competenței valvulare şi în perioada de lungă durată. Concluzii: IMI poate fi considerată ca un marker al remodelării ventriculare în cardiopatia ischemică, iar neglijarea acestor regurgitații îşi lasă amprenta asupra letalității postoperatorii şi stabilității rezultatelor în perioada de lungă durată.IMR as a complication of ischemic heart disease is caused by the LV papillary-annular dysfunction - determining fact in establishing the further treatment tactics of these pathologies. Purpose: To study the developmental mechanism of IMR, reevaluation of surgical indications, appreciation of efficacy and durability of the surgical techniques. Material and methods: In the study field were included 124 patients with IMR, consequence of LV remodeling after ischemia and myocardial infarction.In all cases myocardial revascularization were performed. Simultaneously 85 patients underwent reconstructive techniques to the mitral valve. Among 38 patients with IMR till grade II, the valve pathology was neglected.Results: We observed a tight relation between mechanism of IMR appearance and myocardial infarction zone localization, LV sphericity affectation grade, prevalence of mitral fibrous ring dilatation and valve coaptation point displacement caused by papillary muscle tensioning. Isolated coronary by-pass did not contributed to regression of II grade IMR, and in 25% of cases during a long period, IMR has progressed, while maintaining the LV volume overload.In 56 (69.1%) of cases was applied an innovative technique for mitral annuloplasty with three sutures with a significant reduction of the average degree of regurgitation from 2.7 ± 0.5 preoperatively to 1.2 ± 0.1 postoperatively and ensuring physiological cusp mobility. In parallel, to remove the causes of the manifestation of IMR, patients required LV aneurysm resection in 25 (29.4%) cases and approximation of papillary muscles by Hvass procedure in 18 (21.2%) cases. All these procedures have provided an anatomical and functional restoration of valve competence in immediate and long-term period. Conclusion: IMR may be regarded as a marker of ventricular remodeling in ischemic heart disease and neglecting such of regurgitation influences upon the postoperative mortality rate and stability during long-term results