10 research outputs found

    Artificial gauge potentials for neutral atoms

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    When a neutral atom moves in a properly designed laser field, its center-of-mass motion may mimic the dynamics of a charged particle in a magnetic field, with the emergence of a Lorentz-like force. In this Colloquium we present the physical principles at the basis of this artificial (synthetic) magnetism and relate the corresponding Aharonov-Bohm phase to the Berry's phase that emerges when the atom follows adiabatically one of its dressed states. We also discuss some manifestations of artificial magnetism for a cold quantum gas, in particular in terms of vortex nucleation. We then generalise our analysis to the simulation of non-Abelian gauge potentials and present some striking consequences, such as the emergence of an effective spin-orbit coupling. We address both the case of bulk gases and discrete systems, where atoms are trapped in an optical lattice.Comment: Accepted for publication in Reviews of Modern Physics (Colloquium

    Range of validity of the Hammett equation: acidity of substituted ethynylbenzenes

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    Acidities of 19 meta- and para-substituted ethynylbenzenes were calculated at the B3LYP/6-311+G( d, p) level and correlated within the framework of the Hammett equation with the calculated acidities of equally substituted benzoic acids. The substituent effects were decomposed in terms of isodesmic reactions into those operating in the anions and in the uncharged molecules. Characteristic deviations from the Hammett equation were found for para-substituents, both for acceptors and donors; the former can be interpreted by the resonance formula only with an electron sextet. With reference to the series of ionization reactions investigated previously, it was possible to reinvestigate the validity of the Hammett equation on the basis of calculated reaction energies using a more homogeneous data set than had been ever accessible from the experimental reactivities. The equation was fulfilled for all meta-substituents with a higher accuracy than commonly attainable with the experimental data. When para-substituents were included, deviations occurred according to the character of the functional group: When this group was an acceptor, the donor substituents showed deviations and vice versa. Another series of reactions proceeding between uncharged groups bonded directly on the benzene ring was investigated in the same way: The Hammett equation held with a similar precision, although its original range of validity was surpassed. The properties of a set of common substituents were investigated by principal component analysis and cluster analysis. There is a fundamental difference between uniform acceptors and more discriminated donors but clustering is not so strong to depreciate common statistical analysis

    Logit Model for Estimating Non-Profit Organizations’ Financial Status as a Part of Non-Profit Financial Management

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    The non-profit sector plays an important role in the American and European continents, as non-profit organizations support the development of civil society and help people in need. However, most non-profit organizations (NPO) are financially dependent on various donors from the private sector. Nowadays, non-profit organizations focus on improving their non-profit financial management. This research aims to assess the financial status of Slovak non-profit organizations, using binary logistic regression. The initial sample includes 351 Slovak NPOs, which are divided into a training and test sub-sample. The data were obtained from Amadeus, FinStat, the Ministry of Finance of the Slovak Republic, and the Ministry of Interior of the Slovak Republic. The logit model shows that the significant variables are equity ratio, debt ratio, operating margin, and type of NPO using the statistical–analytical program IBM SPSS 25. The model also implies that non-profit organizations should focus on the revenue structure and revenues from the sale of products. The prediction model correctly classifies 97.03% of NPOs in the training sub-sample and 96.61% of NPOs in the test sub-sample. Moreover, more than 70% of vulnerable NPOs are correctly classified

    The Impact of an Environmental Way of Customer’s Thinking on a Range of Choice from Transport Routes in Maritime Transport

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    The paper deals with the impact that an environmental way of thinking has on shipping and transport company customers regarding their preferences in choosing a transport route. Nowadays, maritime transport plays a very important role mainly in transoceanic container transport. It also deals with the statistics focused on container shipping, especially between North America and Europe. These statistics contribute to a general description of the development of container shipping on the route that is applicated in this case study. The significant impact of this kind of transport also reflects the estimation of the future development of container transport on the selected transport route. In this view, the least square method is used in this paper. This method can present the trend of development according to statistics. Thanks to these materials, this paper estimates a slight increase of the number of containers transported between North America and Europe in the near future. This increase will have a certain effect on the environment. Thus, as part of their business policy of sustainability and environment protection, customers will prefer a mode of transport and transport routes featuring a smaller effect on the environment in the future. The relevance of such a change in preferences in planning transport routes for the customer is reflected in the case study presented in this paper. So, one part of this paper is also dedicated to information about the impact of maritime transport on the environment. This part also explains the impact according to different studies that have been published in the last few years. The main contribution of this paper is also to point out the importance of this factor for the preferences of customers via the multi-criteria decision method. Using a multi-criteria decision method, it outlines how the factor of the impact on the environment can significantly change the offer made by a transport or shipping company, and thus how it represents a key element of whether the customer would prefer the given offer or focus on a competitor’s offer

    The Impact of an Environmental Way of Customer’s Thinking on a Range of Choice from Transport Routes in Maritime Transport

    No full text
    The paper deals with the impact that an environmental way of thinking has on shipping and transport company customers regarding their preferences in choosing a transport route. Nowadays, maritime transport plays a very important role mainly in transoceanic container transport. It also deals with the statistics focused on container shipping, especially between North America and Europe. These statistics contribute to a general description of the development of container shipping on the route that is applicated in this case study. The significant impact of this kind of transport also reflects the estimation of the future development of container transport on the selected transport route. In this view, the least square method is used in this paper. This method can present the trend of development according to statistics. Thanks to these materials, this paper estimates a slight increase of the number of containers transported between North America and Europe in the near future. This increase will have a certain effect on the environment. Thus, as part of their business policy of sustainability and environment protection, customers will prefer a mode of transport and transport routes featuring a smaller effect on the environment in the future. The relevance of such a change in preferences in planning transport routes for the customer is reflected in the case study presented in this paper. So, one part of this paper is also dedicated to information about the impact of maritime transport on the environment. This part also explains the impact according to different studies that have been published in the last few years. The main contribution of this paper is also to point out the importance of this factor for the preferences of customers via the multi-criteria decision method. Using a multi-criteria decision method, it outlines how the factor of the impact on the environment can significantly change the offer made by a transport or shipping company, and thus how it represents a key element of whether the customer would prefer the given offer or focus on a competitor’s offer

    Perceptions of transmission of body weight and telemonitoring in patients with heart failure?

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    Chronic heart failure (HF) is associated with a high burden of morbidity and mortality and with reduced quality of life. New techniques such as telemonitoring (TM) have recently been introduced in the care of patients with HF in order to improve outcomes. TM is defined as sending data from the patients’ home to healthcare professionals. Most studies have focussed on endpoints such as morbidity and mortality, and relatively little attention has been paid to patients’ perceptions of TM. Therefore, the aim of this study was to explore and describe patients’ perceptions of transmission of body weight (BW) and TM, regularly accomplished from patients’ homes to an HF clinic. An explorative design with a phenomenographic approach was used, and semi-structured interviews were conducted with a maximum variation sampling of 20 participants. The findings are described in five metaphoric categories that were assigned and used as a description: the habitual patient, the concerned patient, the technical patient, the secure patient, and the self-caring patient. The conclusions were that the transmission of BW made the patients active in their own care and increased self-care activities. In clinical care, concerns for deterioration in HF as well as the reliability of the TM system should be considered. Future research may focus on healthcare professionals and their perceptions of transmission of BW and TM in the care of patients with HF

    Oxygen targets and 6-month outcome after out of hospital cardiac arrest: a pre-planned sub-analysis of the targeted hypothermia versus targeted normothermia after Out-of-Hospital Cardiac Arrest (TTM2) trial

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    International audienceAbstract Background Optimal oxygen targets in patients resuscitated after cardiac arrest are uncertain. The primary aim of this study was to describe the values of partial pressure of oxygen values (PaO 2 ) and the episodes of hypoxemia and hyperoxemia occurring within the first 72 h of mechanical ventilation in out of hospital cardiac arrest (OHCA) patients. The secondary aim was to evaluate the association of PaO 2 with patients’ outcome. Methods Preplanned secondary analysis of the targeted hypothermia versus targeted normothermia after OHCA (TTM2) trial. Arterial blood gases values were collected from randomization every 4 h for the first 32 h, and then, every 8 h until day 3. Hypoxemia was defined as PaO 2  300 mmHg. Mortality and poor neurological outcome (defined according to modified Rankin scale) were collected at 6 months. Results 1418 patients were included in the analysis. The mean age was 64 ± 14 years, and 292 patients (20.6%) were female. 24.9% of patients had at least one episode of hypoxemia, and 7.6% of patients had at least one episode of severe hyperoxemia. Both hypoxemia and hyperoxemia were independently associated with 6-month mortality, but not with poor neurological outcome. The best cutoff point associated with 6-month mortality for hypoxemia was 69 mmHg (Risk Ratio, RR = 1.009, 95% CI 0.93–1.09), and for hyperoxemia was 195 mmHg (RR = 1.006, 95% CI 0.95–1.06). The time exposure, i.e., the area under the curve (PaO 2 -AUC), for hyperoxemia was significantly associated with mortality ( p = 0.003). Conclusions In OHCA patients, both hypoxemia and hyperoxemia are associated with 6-months mortality, with an effect mediated by the timing exposure to high values of oxygen. Precise titration of oxygen levels should be considered in this group of patients. Trial registration : clinicaltrials.gov NCT02908308 , Registered September 20, 2016

    Ventilatory settings in the initial 72 h and their association with outcome in out-of-hospital cardiac arrest patients: a preplanned secondary analysis of the targeted hypothermia versus targeted normothermia after out-of-hospital cardiac arrest (TTM2) trial

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