Josephson array of mesoscopic objects. Modulation of system properties through the chemical potential

The phase diagram of a two-dimensional Josephson array of mesoscopic objects is examined. Quantum fluctuations in both the modulus and phase of the superconducting order parameter are taken into account within a lattice boson Hubbard model. Modulating the average occupation number $n_0$ of the sites in the system leads to changes in the state of the array, and the character of these changes depends significantly on the region of the phase diagram being examined. In the region where there are large quantum fluctuations in the phase of the superconducting order parameter, variation of the chemical potential causes oscillations with alternating superconducting (superfluid) and normal states of the array. On the other hand, in the region where the bosons interact weakly, the properties of the system depend monotonically on $n_0$. Lowering the temperature and increasing the particle interaction force lead to a reduction in the width of the region of variation in $n_0$ within which the system properties depend weakly on the average occupation number. The phase diagram of the array is obtained by mapping this quantum system onto a classical two-dimensional XY model with a renormalized Josephson coupling constant and is consistent with our quantum Path-Integral Monte Carlo calculations.Comment: 12 pages, 8 Postscript figure

High-precision measurements of krypton and xenon isotopes with a new static-mode quadrupole ion trap mass spectrometer

Measuring the abundance and isotopic composition of noble gases in planetary atmospheres can answer fundamental questions in cosmochemistry and comparative planetology. However, noble gases are rare elements, a feature making their measurement challenging even on Earth. Furthermore, in space applications, power consumption, volume and mass constraints on spacecraft instrument accommodations require the development of compact innovative instruments able to meet the engineering requirements of the mission while still meeting the science requirements. Here we demonstrate the ability of the quadrupole ion trap mass spectrometer (QITMS) developed at the Jet Propulsion Laboratory (Caltech, Pasadena) to measure low quantities of heavy noble gases (Kr, Xe) in static operating mode and in the absence of a buffer gas such as helium. The sensitivity reaches 10^(13) cps Torr^(−1) (about 10^(11) cps Pa^(−1)) of gas (Kr or Xe). The instrument is able to measure gas in static mode for extended periods of time (up to 48 h) enabling the acquisition of thousands of isotope ratios per measurement. Errors on isotope ratios follow predictions of the counting statistics and the instrument provides reproducible results over several days of measurements. For example, 1.7 × 10^(−10) Torr (2.3 × 10^(−8) Pa) of Kr measured continuously for 7 hours yielded a 0.6‰ precision on the ^(86)Kr/^(84)Kr ratio. Measurements of terrestrial and extraterrestrial samples reproduce values from the literature. A compact instrument based upon the QITMS design would have a sensitivity high enough to reach the precision on isotope ratios (e.g. better than 1% for ^(129,131–136)Xe/^(130)Xe ratios) necessary for a scientific payload measuring noble gases collected in the Venus atmosphere

Об одном достаточном условии нерегулярности языков

The article deals with a proof of one sufficient condition for the irregularity of languages. This condition is related to the properties of certain relations on the set of natural numbers, namely relations possessing the property, referred to as strong separability. In turn, this property is related to the possibility of decomposition of an arithmetic vector space into a direct sum of subspaces. We specify languages in some finite alphabet through the properties of a vector that shows the number of occurrences of each letter of the alphabet in the language words and is called the word distribution vector in the word. The main result of the paper is the proof of the theorem according to which a language given in such a way that the vector of distribution of letters in each word of the language belongs to a strongly separable relation on the set of natural numbers is not regular. Such an approach to the proof of irregularity is based on the Myhill-Nerode theorem known in the theory of formal languages, according to which the necessary and sufficient condition for the regularity of a language consists in the finiteness of the index of some equivalence relation defined by the language.The article gives a definition of a strongly separable relation on the set of natural numbers and examines examples of such relations. Also describes a construction covering a considerably wide class of strongly separable relations and connected with decomposition of the even-dimensional vector space into a direct sum of subspaces of the same dimension. Gives the proof of the lemma to assert an availability of an infinite sequence of vectors, any two terms of which are pairwise disjoint, i.e. one belongs to some strongly separable relation, and the other does not. Based on this lemma, there is a proof of the main theorem on the irregularity of a language defined by a strongly separable relation.This result sheds additional light on the effectiveness of regularity / irregularity analysis tools based on the Myhill-Neroud theorem. In addition, the proved theorem and analysis of some examples of strongly separable relations allows us to establish non-trivial connections between the theory of formal languages and the theory of linear spaces, which, as analysis of sources shows, is relevant.In terms of development of the obtained results, the problem of the general characteristic of strongly separable relations is of interest, as well as the analysis of other properties of numerical sets that are important from the point of view of regularity / irregularity analysis of languages.Данная статья посвящена доказательству одного достаточного условия нерегулярности языков. Это условие связано со свойствами некоторых отношений на множестве натуральных чисел, а именно отношений, обладающих свойством, названное сильной отделимостью. В свою очередь, это свойство связано с возможностью разложения арифметического векторного пространства в прямую сумму подпространств. Мы задаем языки в некотором конечном алфавите через свойства вектора, показывающего числа вхождений каждой буквы алфавита в слова языка и называемого вектором распределения букв в слове. Основной результат статьи состоит в доказательстве теоремы, согласно которой язык, задаваемый таким образом, что вектор распределения букв в каждом слове языка принадлежит сильно отделимому отношению на множестве натуральных чисел, нерегулярен. Такой подход к доказательству нерегулярности основан на известной в теории формальных языков теореме Майхилла-Нероуда, согласно которой необходимое и достаточное условие регулярности языка состоит в конечности индекса некоторого отношения эквивалентности, определяемого языком.В статье дается определение сильно отделимого отношения на множестве натуральных чисел и рассматриваются примеры таких отношений. Дается также описание конструкции, покрывающей весьма широкий класс сильно отделимых отношений и связанной с разложением векторного пространства четной размерности в прямую сумму подпространств одинаковой размерности. Доказывается лемма, утверждающая существование бесконечной последовательности векторов, любые два члена которой попарно дизъюнктны, т.е. один принадлежит некоторому сильно отделимому отношению, а другой нет. На основании этой леммы доказывается основная теорема о нерегулярности языка, определяемым сильно отделимым отношением.Этот результат проливает дополнительный свет на эффективность инструментов анализа регулярности/нерегулярности языков, базирующихся на теореме Майхилла-Нероуда. Кроме того, доказанная теорема и анализ некоторых примеров сильно отделимых отношений позволяет установить нетривиальные связи между теорией формальных языков и теорией линейных пространств, что, как показывает анализ источников, является актуальной проблематикой.В плане развития полученных результатов интерес представляет задача общей характеристики сильно отделимых отношений, а также анализ других свойств числовых множеств, важных с точки зрения анализа регулярности/нерегулярности языков

Influence of vesicourethral segment reconstruction techniques in radical prostatectomy on urinary continence: evaluation of immediate and long-term outcomes

Introduction. Currently, various methods and modifications of radical prostatectomy (RP) have been developed and tested, aimed at preventing and minimizing the development of urinary incontinence (UI). However, UI remains an urgent problem in patients who undergo RP, especially at the early follow-up stages.Objective. To evaluate and compare the effectiveness of modified reconstructive techniques for vesicourethral anastomosis in radical prostatectomy for the prevention of urinary incontinence with respect to the standard technique at different follow-up periods.Materials and methods. Design: single-centre, clinical, simple, comparative, parallel-group study with retrospective and prospective material evaluation, conducted in 2017 – 2022. Patients: men with verified prostate cancer cT1a – 2cN0 – xM0 without decompensated comorbidities. Age: 45 – 78 years. Retrospective part — group (G) 1: 90 patients who underwent non-nerve-sparing open retropubic RP with a "classic" vesicourethral anastomosis (VUA). Prospective part — G2: 46 patients who underwent similar surgery with modified VUA in two variations: without and with prostatic urethra-sparing — G2a (n = 25) and G2b (n = 21), respectively. Initial examination: standard preoperative laboratory and instrumental examination, assessment of lower urinary tract symptoms (LUTS) using the IPSS-QoL questionnaire. Follow-up examination: objective evaluation of UI according to established criteria and subjective assessment using the ICIQ-SF questionnaire, tracking the dynamics of LUTS using IPSS-QoL. Follow-up periods: 0-point (after catheter removal), 1, 3, 6, and 12 months (exit-point); the dynamics of recovery of urinary continence (UC) was determined monthly. Statistical analysis: Statistica ver.10.0 (StatSoft Inc., Tulsa, OK, USA) using non-parametric methods (CL p < 0.05 at a = 0.05)Results. Preoperative demographic, questionnaire and instrumental statistics did not differ (p > 0.05) between the groups, confirming the homogeneity of the samples. After RP, the urethral catheter was removed in a period of 7 to 21 days. There was no difference (p > 0.05) in the duration of drainage between the groups. Total urinary continence (TUC) immediately after catheter removal was detected in G1, G2a and G2b in 20.0%, 44.0% and 57.1% of cases, respectively. Subsequent objective monitoring of UC recovery from 1 month showed differences (p < 0.001) between the groups in the dynamics of rehabilitation during the year. The improvement in UC over the one-year follow-up period was cumulatively achieved in G1, G2a and G2b in 48.9%, 44.0% and 33.3% of cases, respectively. Total UI persisted in G1 and G2a by month 12 in 22.2% and 8.0% of patients, respectively, and was not detected in G2b. The severity of UI by the end of the follow-up according to the ICIQ-SF data was the most pronounced (p < 0.001) in patients from G1. TUC-patients in all groups from 1 month showed a marked decrease in the severity of obstructive and irritative LUTS and improved quality of life, with no differences (0.157 < p < 0.390) in IPSS-QoL values between groups.Conclusions. The use of modified VUA reconstruction techniques made it possible, compared with the standard one, to achieve high continence rates in patients both immediately after the removal of the urethral catheter and at subsequent follow-up periods, without the formation of severe iatrogenic obstruction. Prostatic urethra-sparing modification is the most effective technique that provided the rehabilitation of UI to a complete and/or social level in all patients within a year after surgery

Quantum effects on the BKT phase transition of two-dimensional Josephson arrays

The phase diagram of two dimensional Josephson arrays is studied by means of the mapping to the quantum XY model. The quantum effects onto the thermodynamics of the system can be evaluated with quantitative accuracy by a semiclassical method, the {\em pure-quantum self-consistent harmonic approximation}, and those of dissipation can be included in the same framework by the Caldeira-Leggett model. Within this scheme, the critical temperature of the superconductor-to-insulator transition, which is a Berezinskii-Kosterlitz-Thouless one, can be calculated in an extremely easy way as a function of the quantum coupling and of the dissipation mechanism. Previous quantum Monte Carlo results for the same model appear to be rather inaccurate, while the comparison with experimental data leads to conclude that the commonly assumed model is not suitable to describe in detail the real system.Comment: 4 pages, 2 figures, to be published in Phys. Rev.

Vimentin is a novel AKT1 target mediating motility and invasion.

The PI3K/AKT signaling pathway is aberrant in a wide variety of cancers. Downstream effectors of AKT are involved in survival, growth and metabolic-related pathways. In contrast, contradictory data relating to AKT effects on cell motility and invasion, crucial prometastatic processes, have been reported pointing to a potential cell type and isoform type-specific AKT-driven function. By implication, study of AKT signaling should optimally be conducted in an appropriate intracellular environment. Prognosis in soft-tissue sarcoma (STS), the aggressive malignancies of mesenchymal origin, is poor, reflecting our modest ability to control metastasis, an effort hampered by lack of insight into molecular mechanisms driving STS progression and dissemination. We examined the impact of the cancer progression-relevant AKT pathway on the mesenchymal tumor cell internal milieu. We demonstrate that AKT1 activation induces STS cell motility and invasiveness at least partially through a novel interaction with the intermediate filament vimentin (Vim). The binding of AKT (tail region) to Vim (head region) results in Vim Ser39 phosphorylation enhancing the ability of Vim to induce motility and invasion while protecting Vim from caspase-induced proteolysis. Moreover, vimentin phosphorylation was shown to enhance tumor and metastasis growth in vivo. Insights into this mesenchymal-related molecular mechanism may facilitate the development of critically lacking therapeutic options for these devastating malignancies

Heterotopic Gastric Mucosa in Cervical Oesophagus: Clinical Observations

Aim. Description of the endoscopic and clinical traits of heterotopic gastric mucosa (HGM) observed in cervical oesophagus.Key points. HGM in proximal oesophagus can be asymptomatic or have various clinical manifestations. A 40-yo female patient consulted a gastroenterologist with complaints of cough and globus sensation. For several years she was visiting an otorhinolaryngologist and psychotherapist, with therapy ineffective. Esophagogastroduodenoscopy (EGDS) at the last visit revealed several foci of HGM in cervical oesophagus of 1.2 x 0.8 cm maximal size. The patient was prescribed a combined prokinetic — proton pump inhibitor therapy, which relieved the symptoms. EGDS in a 21-yo patient without active complaints revealed a 2 cm-wide HGM of 4/5 cervical oesophageal lining with acidproducing zones.Conclusion. Two different scenarios of cervical oesophageal HGM are described, the first one manifested with laryngopharyngeal reflux, and the second devoid of clinical manifestations despite a large heterotopic site

Esophageal Lichen Planus as a Cause of Dysphagia: Literature Review and Clinical Observation

Aim: to analyze the literature data, and to raise awareness of doctors of various specialties about the methods of diagnosis and treatment of esophageal lichen planus (ELP).Key points. In a 67-year-old female patient with complaints of difficulty swallowing solid food and weight loss, esophagogastroduodenoscopy revealed subcompensated stenosis of the middle third of the esophagus and signs of fibrinous esophagitis. Based on the characteristics of the endoscopic picture and the detection of apoptotic Ciwatt bodies in esophageal biopsies, a diagnosis of ELP was established. Treatment with glucocorticosteroids led to relief of symptoms and positive endoscopic dynamics. ELP is rare and the least studied, data on this disease in the literature are presented mainly in the form of clinical observations and analysis of series of cases. Typical clinical manifestations include dysphagia and odynophagia. Despite the low prevalence, ELP can be associated with serious complications: stenosis and esophageal squamous cell carcinoma. Endoscopic examination reveals characteristic signs in the esophagus: swelling, thickening and increased vulnerability of the mucosa, often with fibrin, formation of membranes and strictures. The histological picture is represented by epithelial dyskeratosis with exfoliation, lichenoid lymphocytic infiltration. The most specific histological sign is the presence of apoptotic Civatte bodies. Recommendations for the treatment of ELP are limited to the results of a series of clinical observations and include the prescription of systemic corticosteroids. The issue of supportive therapy is the least studied.Conclusion. Analysis of the literature data and the clinical case demonstrate that lichen planus of the esophagus is one of the rare causes of dysphagia. Characteristic endoscopic and histological signs are key for the diagnosis. The management of patients with esophageal lichen planus is insufficiently defined and today includes taking of glucocorticosteroids, endoscopic dilation of stricture and dynamic endoscopic observation, given the high risk of squamous cell carcinoma in this category of patients

Correlation functions near Modulated and Rough Surfaces

In a system with long-ranged correlations, the behavior of correlation functions is sensitive to the presence of a boundary. We show that surface deformations strongly modify this behavior as compared to a flat surface. The modified near surface correlations can be measured by scattering probes. To determine these correlations, we develop a perturbative calculation in the deformations in height from a flat surface. Detailed results are given for a regularly patterned surface, as well as for a self-affinely rough surface with roughness exponent $\zeta$. By combining this perturbative calculation in height deformations with the field-theoretic renormalization group approach, we also estimate the values of critical exponents governing the behavior of the decay of correlation functions near a self-affinely rough surface. We find that for the interacting theory, a large enough $\zeta$ can lead to novel surface critical behavior. We also provide scaling relations between roughness induced critical exponents for thermodynamic surface quantities.Comment: 31 pages, 2 figure

Public political narratives: developing a neglected source through the exploratory case of Russia in the Putin-Medvedev era

The place of narrative in political science is an issue that resurfaces with regularity, usually focusing on the questions of generalisability, evidence and causality which lie at the heart of the discipline. Most such debate concerns the use of narrative by political scientists. Far less attention has been devoted to the use of narrative by political actors, despite its relative ubiquity. Even where such attention has been given, it concentrates less on the narrative per se, and more on its performance and impact. However, the nature of public political narratives means that analysis of them facilitates a holistic understanding of their narrators' politics. A public political narrative consists of a sequential account given by political actors connecting selected, specific developments so as to impose a desired order on them. Taking contemporary Russia as an exploratory case, narrative analysis draws out the motivations, world view and inconsistencies within the Putin-Medvedev regime. Recurring motifs and symbols identify the regime's political priorities, explaining policy choices and revealing future concerns. Narrative has a predictive aspect, identifying likely policy responses to unexpected events. Narratives capture time, and shifts in their temporalities indicate changes in self-conceptualisation and political priorities. Temporal appropriations include or exclude particular agential and causal explanations. The relationship between their plots and subplots represents a political signalling process. Public political narratives provide temporally and spatially specific exceptionalist accounts, but their combinatory quality also facilitates comparative analysis. The approach essayed here provides methodological generalisability, arguing that the neglect of public political narratives merits correcting