Controlled collisions of a single atom and ion guided by movable trapping potentials

We consider a system composed of a trapped atom and a trapped ion. The ion charge induces in the atom an electric dipole moment, which attracts it with an r^{-4} dependence at large distances. In the regime considered here, the characteristic range of the atom-ion interaction is comparable or larger than the characteristic size of the trapping potential, which excludes the application of the contact pseudopotential. The short-range part of the interaction is described in the framework of quantum-defect theory, by introducing some short-range parameters, which can be related to the s-wave scattering length. When the separation between traps is changed we observe trap-induced shape resonances between molecular bound states and vibrational states of the external trapping potential. Our analysis is extended to quasi-one-dimensional geometries, when the scattering exhibit confinement-induced resonances, similar to the ones studied before for short-range interactions. For quasi-one-dimensional systems we investigate the effects of coupling between the center of mass and relative motion, which occurs for different trapping frequencies of atom and ion traps. Finally, we show how the two types of resonances can be employed for quantum state control and spectroscopy of atom-ion molecules.Comment: 17 pages, 16 figure

Micromechanics of sea urchin spines

The endoskeletal structure of the Sea Urchin, Centrostephanus rodgersii, has numerous long spines whose known functions include locomotion, sensing, and protection against predators. These spines have a remarkable internal microstructure and are made of single-crystal calcite. A finite-element model of the spine's unique porous structure, based on micro-computed tomography (microCT) and incorporating anisotropic material properties, was developed to study its response to mechanical loading. Simulations show that high stress concentrations occur at certain points in the spine's architecture; brittle cracking would likely initiate in these regions. These analyses demonstrate that the organization of single-crystal calcite in the unique, intricate morphology of the sea urchin spine results in a strong, stiff and lightweight structure that enhances its strength despite the brittleness of its constituent material

Protecting wound edges from infection using an Alexis wound retractor

Wstęp. Zakażenia ran operacyjnych towarzyszą ludzkości od zarania dziejów. Przez wieki były jedną z głównych przyczyn zgonów. Pomimo rozwoju wielu dziedzin życia, postęp w ich leczeniu nastąpił faktycznie w ciągu ostatnich stu siedemdziesięciu lat. Niemniej jednak problem zakażeń ran operacyjnych jest nadal aktualny pomimo szerokiego zastosowania działań profilaktycznych. Uważa się, że ilość tego rodzaju zakażeń jest jednym z najistotniej-szych wyznaczników rozwoju medycyny. Autorzy założyli, że zastosowanie jednorazowego retraktora ran Alexis zmniejszy ilość zakażeń ran operacyjnych, w szczególności u chorych wysokiego ryzyka. Materiał i metoda. W celu rozwiązania problemu badawczego zastosowano metodę badań reprezentacyjnych, a jako narzędzie badawcze posłużył arkusz analizy dokumentów. Autorzy przyjęli, że badanie będzie wiarygodne, gdy ryzyko zakażenia rany operacyjnej będzie odpowiednio duże. Chorzy, spełniający założone kryteria, zostali zakwalifikowani do dwóch losowo z kompletowanych grup. Obie grupy liczyły po 15 osób, przy czym wiek grupy badanej wahał się pomiędzy 54-83 lat, zaś grupy kontrolnej 57-86 lat. W grupie badanej stosowano retraktor, w grupie kontrolnej nie. Rana operacyjna była oceniana w trakcie hospitalizacji pacjenta codziennie, a po wy-pisaniu z oddziału okresowo do 30-ego dnia po operacji. W przypadku pojawienia się infekcji w ranie, została ona potwierdzona bada-niem mikrobiologicznym. Wyniki i wnioski. W oparciu o analizę wyników badań można stwierdzić, że u chorych z grupy podwyższonego ryzyka zastosowanie retraktora ran operacyjnych Alexis zmniejsza prawdopodobieństwo zakażenia rany operacyjnej, a skuteczna mechaniczna protekcja rany operacyjnej powinna stać się stałym elementem działań profilaktycznych zmierzających do ograniczenia ilości zakażeń ran operacyjny.Introduction. The infections of surgical wounds have been very much around since the beginnings of mankind. For ages they have been one of the predominant causes of death. Despite the fact that many aspects of life have undergone rapid developments, the progress in surgical wound treatment emerged during the last 170 years. Nevertheless, the problem of surgical wound infection is still a threat even despite many preventive actions. It is widely acknowledged that the number of those infections is one of the most crucial indicator of the development of medicine. The author has assumed that the use of a disposable Alexis wound retractor is going to decrease the number of surgical infections, especially among high-risk patients. The material and the method. In order to solve the research problem, the sampling procedure method was used. The research instrument was document analysis worksheet. The authors assumed that the re-search would be more credible if the risk of surgical wound infection is high enough. The patients who met the criteria were divided randomly into two groups. Both groups had 15 people; their ages varied from 54 to 83 in the sample group and from 57 to 86 in the control group. The retractor was used in the sample group and not in the control group. The surgical wounds were assessed each day while the patient stayed at the hospital, and after that periodically until 30 days after the operation. If the wound started showing indications of an infection, a microbiological test was run to confirm it. The results and conclusions. Judging by the analysis of the research results, one can conclude that the use of an Alexis surgical wound retractor on high-risk patients decreases the probability of a wound infection and the effective mechanical protection of surgical wounds should become a constant element of preventive actions aimed at limiting the number of surgical wound infections

Specific problems of nursing patients suffering from Mayer-Rokitansky-Küster-Hauser syndrome

W pracy przedstawiono opis przypadku chorej z zespołem Mayera-Rokitansky'ego-Küstera-Hausera. Scharakteryzowano czynniki etiologiczne, obraz kliniczny, diagnostykę i metody leczenia. Szczególną uwagę zwrócono na specyficzne problemy pielęgnacyjne osób z tym zespołem.Introduction. This paper presents a case description of a woman suffering from Mayer-Rokitansky-Küster-Hauser Syndrome. The etiological factors, the clinical presentation as well as the diagnostics and methods of treatment were scrutinized in this paper. Special attention was devoted to specific problems of nursing patients suffering from that syndrome

First-order coherence versus entanglement in a nano-mechanical cavity

The coherence and correlation properties of effective bosonic modes of a nano-mechanical cavity composed of an oscillating mirror and containing an optical lattice of regularly trapped atoms are studied. The system is modeled as a three-mode system, two orthogonal polariton modes representing the coupled optical lattice and the cavity mode, and one mechanical mode representing the oscillating mirror. We examine separately the cases of two-mode and three-mode interactions which are distinguished by a suitable tuning of the mechanical mode to the polariton mode frequencies. In the two-mode case, we find that the occurrence of entanglement between one of the polariton modes and the mechanical mode is highly sensitive to the presence of the first-order coherence between the modes. In particular, the creation of the first-order coherence among the modes is achieved at the expense of entanglement between the modes. In the three-mode case, we show that no entanglement is created between the independent polariton modes if both modes are coupled to the mechanical mode by the parametric interaction. There is no entanglement between the polaritons even if the oscillating mirror is damped by a squeezed vacuum field. The interaction creates the first-order coherence between the polaritons and the degree of coherence can, in principle, be as large as unity. This demonstrates that the oscillating mirror can establish the first-order coherence between two independent thermal modes. A further analysis shows that two independent thermal modes can be made entangled in the system only when one of the modes is coupled to the intermediate mode by a parametric interaction and the other is coupled by a linear-mixing interaction.Comment: Published versio

A missing link? Maintaining support for the European polity after the Russian invasion of Ukraine

Recent research argues that external threats like war spur EU polity formation (Kelemen & McNamara, 2022). One key mechanism of this process is public support for policy responses designed by policymakers. However, like the ‘rally-round-the-flag’ effect (Mueller, 1970), public support wanes over time and we decompose this decrease into two elements: salience and polarisation at the domestic level for national and European policies in both soft and hard security (aid and sanctions). We show that while salience can sustain public support for European policy innovations, polarisation about national and (unexpectedly) European policies accelerates its decline. We thus qualify the story of EU polity formation through external security crises

Atrial fibrillation in the practice of medical rescue teams : the analysis of the selected epidemiological features

Wstęp. Migotanie przedsionków jest schorzeniem o niejednolitej etiologii oraz zróżnicowanym obrazie klinicznym. Stanowi jedno z wyzwań współczesnego Systemu Ratownictwa Medycznego. Celem pracy była analiza wybranych danych epidemiologicznych pacjentów z migotaniem przedsionków, u których interweniowały zespoły ratownictwa medycznego. Materiał i metodyka. Badaniami objęto 147 chorych (88 kobiet i 59 mężczyzn) w wieku od 22 do 97 lat (średnia 72,49 lat) z migotaniem przedsionków. Wyniki. Migotanie przedsionków częściej występowało u kobiet niż u mężczyzn (61% vs 39%). Średnia wieku kobiet była wyższa od średniej wieku mężczyzn (74,3 lat vs 69,72 lat). Najwięcej interwencji medycznych dotyczyło pacjentów w grupie wiekowej 70-79 lat. Wnioski. Migotanie przedsionków wykazuje sezonowość występowania, najwięcej przypadków dotyczy okresu zimowego oraz godzin porannych. Częstość występowania migotania przedsionków wzrasta wraz z wiekiem i najczęściej dotyczy kobiet.Introduction. Atrial fibrillation is a condition of heterogeneous aetiology and diversified clinical presentation. It is one of the challenges the medical rescue system has to face. The purpose of the paper was to analyse selected epidemiological data of patients suffering from atrial fibrillation who required the intervention of a medical rescue team. The material and methods. The research was conducted on 147 patients (88 women and 59 men) aged from 22 to 97 (the average age being 72,49 years of age) suffering from atrial fibrillation. The results. Atrial fibrillation is more common is the case of women (61% vs. 39%). The average age of women was higher than that of men (74,3 vs. 69,72). The greatest number of medical interventions was observed in the age group of 70 to 79 years of age. Conclusions. The occurrence of atrial fibrillation was observed to be time-specific, with the majority of the cases occurring during winter and in the morning. The frequency of atrial fibrillation occurrence increases with age and is more common is the case of women

Analytical solutions for the dynamics of two trapped interacting ultracold atoms

We discuss exact solutions of the Schroedinger equation for the system of two ultracold atoms confined in an axially symmetric harmonic potential. We investigate different geometries of the trapping potential, in particular we study the properties of eigenenergies and eigenfunctions for quasi-one- and quasi-two-dimensional traps. We show that the quasi-one- and the quasi-two-dimensional regimes for two atoms can be already realized in the traps with moderately large (or small) ratios of the trapping frequencies in the axial and the transverse directions. Finally, we apply our theory to Feshbach resonances for trapped atoms. Introducing in our description an energy-dependent scattering length we calculate analytically the eigenenergies for two trapped atoms in the presence of a Feshbach resonance.Comment: RevTeX, 15 pages, 15 figure