145 research outputs found
New phase structure of the Nambu -- Jona - Lasinio model at nonzero chemical potential
It is shown that in the Nambu -- Jona - Lasinio model at nonzero chemical
potential there are two different massive phases with spontaneously broken
chiral symmetry. In one of them particle density is identically zero, in
another phase it is not equal to zero. The transition between phases is a phase
transition of the second order.Comment: 8 pages, LaTeX, no figures
Formation of the internal structure of solids under severe action
On the example of a particular problem, the theory of vacancies, a new form
of kinetic equations symmetrically incorporation the internal and free energies
has been derived. The dynamical nature of irreversible phenomena at formation
and motion of defects (dislocations) has been analyzed by a computer
experiment. The obtained particular results are extended into a thermodynamic
identity involving the law of conservation of energy at interaction with an
environment (the 1st law of thermodynamics) and the law of energy
transformation into internal degree of freedom (relaxation). The identity is
compared with the analogous Jarzynski identity. The approach is illustrated by
simulation of processes during severe plastic deformation, the Rybin kinetic
equation for this case has been derived.Comment: 9 pages, 5 figure
Notes on the Third Law of Thermodynamics.I
We analyze some aspects of the third law of thermodynamics. We first review
both the entropic version (N) and the unattainability version (U) and the
relation occurring between them. Then, we heuristically interpret (N) as a
continuity boundary condition for thermodynamics at the boundary T=0 of the
thermodynamic domain. On a rigorous mathematical footing, we discuss the third
law both in Carath\'eodory's approach and in Gibbs' one. Carath\'eodory's
approach is fundamental in order to understand the nature of the surface T=0.
In fact, in this approach, under suitable mathematical conditions, T=0 appears
as a leaf of the foliation of the thermodynamic manifold associated with the
non-singular integrable Pfaffian form . Being a leaf, it cannot
intersect any other leaf const. of the foliation. We show that (N) is
equivalent to the requirement that T=0 is a leaf. In Gibbs' approach, the
peculiar nature of T=0 appears to be less evident because the existence of the
entropy is a postulate; nevertheless, it is still possible to conclude that the
lowest value of the entropy has to belong to the boundary of the convex set
where the function is defined.Comment: 29 pages, 2 figures; RevTex fil
The crystal growth and properties of novel magnetic double molybdate RbFe(MoO) with mixed Fe/Festates and 1D negative thermal expansion
Single crystals of new compound RbFe(MoO) were successfully grown by the flux method, and their crystal structure was determined using the X-ray single-crystal diffraction technique. The XRD analysis showed that the compound crystallizes in the monoclinic space group P21/m, with unit cell parameters a = 6.8987(4), b = 21.2912(12) and c = 8.6833(5) Å, β = 102.1896(18)°, V = 1246.66(12) Å, Z (molecule number in the unit cell) = 2, R-factor (reliability factor) = 0.0166, and T = 293(2) K. Raman spectra were collected on the single crystal to show the local symmetry of MoO tetrahedra, after the confirmation of crystal composition using energy dispersive X-ray spectroscopy (EDS). The polycrystalline samples were synthesized by a solid-state reaction in the Ar atmosphere; the particle size and thermal stability were investigated by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) analyses. The compound decomposes above 1073 K in an Ar atmosphere with the formation of Fe(III) molybdate. The thermal expansion coefficient along the c direction has the value α = −1.3 ppm K over the temperature range of 298–473 K. Magnetic measurements revealed two maxima in the magnetization below 20 K, and paramagnetic behavior above 50 K with the calculated paramagnetic moment of 12.7 μB per formula unit is in good agreement with the presence of Fe and Fe in the high-spin (HS) state. The electronic structure of RbFe5(MoO4)7 is comparatively evaluated using X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations
ПРОДЛЁННЫЙ СБРОС ВОЗДУХА ПОСЛЕ ЛОБЭКТОМИИ У БОЛЬНЫХ РАКОМ ЛЕГКОГО
Background. Air-leak after lung resection is a common complication occurring in 30–50 % of patients immediately after surgery. The prolonged air-leak (PAL) is a serious problem if it lasts more than 5 days after lung surgery with the reported incidence of 15 %. Despite the progress in thoracic surgery including energy-based vessel-sealing devices and digital drainage systems, there is no universal agreement on the optimal treatment of patients with prolonged air-leaks. The aim of the study: to improve postoperative outcomes in patients with PAL by optimization of postoperative treatment algorithm. Material and methods. Treatment outcomes were analyzed in 194 patients, who underwent lobectomy for non-small cell lung cancer in 2017–2018. results. The prolonged air-leak was detected in 19 (9.8 %) patients after. The average time interval between surgery and development of this complication was 3.4 days. There was no mortality in our series. The median postoperative hospital stay was 8.7 days in patients with non-complicated postoperative period and 14.8 days in patients with PAL. Based on our own experience and practice we have developed and implemented an algorithm of the management of patients with PAL. Conclusion. The treatment of patients with PAL should be based on multidisciplinary approach providing safety of the patients after major lung resection. Each case with PAL should be discussed individually to achieve better results.Актуальность. Недостаточность аэростаза после резекции легкого является распространённым осложнением, которое встречается у 30–50 % больных в течение первых суток послеоперационного периода. Под продленным сбросом воздуха (ПСВ) понимают его поступление по дренажам более 5 сут. Частота ПСВ достигает 15 %. Несмотря на прогресс торакальной хирургии, включающий внедрение новейших сшивающих аппаратов и энергетических инструментов, интеллектуальных систем дренирования плевральной полости, различных методов плевродеза, стандартного подхода в лечении данного осложнения не существует. Наличие продленного сброса воздуха по дренажам ухудшает течение послеоперационного периода и способно вызвать фатальные осложнения. Цель исследования – улучшение непосредственных результатов лобэктомий у больных раком легкого за счёт оптимизации послеоперационного периода при развитии продленного сброса воздуха. Материал и методы. Проведен анализ результатов лечения 194 пациентов, которым была выполнена лобэктомия с систематической ипсилатеральной лимфодиссекцией в 2017–18 гг. Результаты. В исследование включено 19 (9,8 %) пациентов с недостаточностью аэростаза. Летальности не было. Средний интервал между операцией и развитием осложнения составил 3,4 дня. Средний койко-день у пациентов с неосложненным послеоперационным периодом – 8,7 сут, у больных с ПСВ – 14,8 сут. На основании анализа результатов исследования и данных других клиник разработан собственный алгоритм лечения пациентов с длительным поступлением воздуха по дренажам, который применяется в повседневнойпрактике. Заключение. Лечение больных с продлённым сбросом воздуха имеет мультидисциплинарный характер и обеспечивает приемлемый результат. Каждый случай ПСВ в послеоперационном периоде должен рассматриваться индивидуально, так как в настоящее время нет единого стандартизированного алгоритма ведения данных пациентов.
Identity Leadership, Employee Burnout and the Mediating Role of Team Identification: Evidence from the Global Identity Leadership Development Project
Do leaders who build a sense of shared social identity in their teams thereby protect them from the adverse effects of workplace stress? This is a question that the present paper explores by testing the hypothesis that identity leadership contributes to stronger team identification among employees and, through this, is associated with reduced burnout. We tested this model with unique datasets from the Global Identity Leadership Development (GILD) project with participants from all inhabited continents. We compared two datasets from 2016/2017 (n = 5290; 20 countries) and 2020/2021 (n = 7294; 28 countries) and found very similar levels of identity leadership, team identification and burnout across the five years. An inspection of the 2020/2021 data at the onset of and later in the COVID-19 pandemic showed stable identity leadership levels and slightly higher levels of both burnout and team identification. Supporting our hypotheses, we found almost identical indirect effects (2016/2017, b = −0.132; 2020/2021, b = −0.133) across the five-year span in both datasets. Using a subset of n = 111 German participants surveyed over two waves, we found the indirect effect confirmed over time with identity leadership (at T1) predicting team identification and, in turn, burnout, three months later. Finally, we explored whether there could be a “too-much-of-a-good-thing” effect for identity leadership. Speaking against this, we found a u-shaped quadratic effect whereby ratings of identity leadership at the upper end of the distribution were related to even stronger team identification and a stronger indirect effect on reduced burnout
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