The Bose gas beyond mean field

We study a homogeneous Bose gas with purely repulsive forces. Using the Kac scaling of the binary potential we derive analytically the form of the thermodynamic functions of the gas for small but finite values of the scaling parameter in the low density regime. In this way we determine dominant corrections to the mean-field theory. It turns out that repulsive forces increase the pressure at fixed density and decrease the density at given chemical potential (the temperature is kept constant). They also flatten the Bose momentum distribution. However, the present analysis cannot be extended to the region where the mean-field theory predicts the appearence of condensate.Comment: 19 pages, 3 figure

The Lived Experience of Personnel Adversely Impacted by Toxic Leadership: A Phenomenological Study

The purpose of this qualitative phenomenological study was to understand the lived experience of personnel adversely impacted by toxic leadership. This topic is important to study because the harassment, bullying, and narcissistic behavior exhibited by toxic leaders and negative environments have severe adverse implications for personnel, such as reduced accomplishments, mental health, lack of trust, and overall wellbeing. In order to further understand the phenomenon, the following research questions guided the study: (a) What is the lived experience of personnel adversely impacted by toxic leadership? (b) How were the personnel impacted by the change in the culture and environment? (c) What was each person’s response to the change? (d) What was each person’s response to the toxic environment? The theory guiding this study was Weber’s leadership theory, which is where leaders can both positively and negatively impact subordinates. Social constructivism will be used to understand the participants’ lived experiences. The snowball sampling technique was used and resulted in 1,129 people completing the online survey and 29 people completing a semi-structured interview and submitting written statements of who they were before and after the lived. Pattern, theme, and content analysis was conducted to analyze the data. The research revealed that leadership, or what was defined as toxic leadership, was identified and prevalent in organizations by almost every single respondent. The narcissistic, harmful, and bullying behavior was normally followed by no response at all or support of the toxic manager by the organization. This resulted in further targeting by the toxic managers or followers and adversely impacted personnel’s short- and long-term mental, physical, and emotional health

Field induced stationary state for an accelerated tracer in a bath

Our interest goes to the behavior of a tracer particle, accelerated by a constant and uniform external field, when the energy injected by the field is redistributed through collision to a bath of unaccelerated particles. A non equilibrium steady state is thereby reached. Solutions of a generalized Boltzmann-Lorentz equation are analyzed analytically, in a versatile framework that embeds the majority of tracer-bath interactions discussed in the literature. These results --mostly derived for a one dimensional system-- are successfully confronted to those of three independent numerical simulation methods: a direct iterative solution, Gillespie algorithm, and the Direct Simulation Monte Carlo technique. We work out the diffusion properties as well as the velocity tails: large v, and either large -v, or v in the vicinity of its lower cutoff whenever the velocity distribution is bounded from below. Particular emphasis is put on the cold bath limit, with scatterers at rest, which plays a special role in our model.Comment: 20 pages, 6 figures v3:minor corrections in sec.III and added reference

Black hole masses from power density spectra: determinations and consequences

We analyze the scaling of the X-ray power density spectra with the mass of the black hole on the example of Cyg X-1 and Seyfert 1 galaxy NGC 5548. We show that the high frequency tail of the power density spectrum can be successfully used for determination of the black hole mass. We determine the masses of the black holes in 6 Broad Line Seyfert 1 galaxies, 5 Narrow Line Seyfert 1 galaxies and two QSOs using available power density spectra. The proposed scaling is clearly appropriate for other Seyfert galaxies and QSOs. In all but 1 normal Seyferts the resulting luminosity to the Eddington luminosity ratio is smaller than 0.15, with a source MCG -6-15-30 being an exception. The applicability of the same scaling to Narrow Line Seyfert 1 is less clear and there may be a systematic shift between the power spectra of NLS1 and S1 galaxies of the same mass, leading to underestimation of the black hole mass. However, both the method based on variability and the method based on spectral fitting show that those galaxies have relatively low masses and high luminosity to the Eddington luminosity ratio, supporting the view of those objects as analogs of galactic sources in their high/soft or very high state based on the overall spectral shape. Bulge masses of their host galaxies are similar to normal Seyfert galaxies so they do not follow the black hole mass-bulge mass relation for Seyfert galaxies, being evolutionary less advanced, as suggested by Mathur (2000). The bulge mass-black hole mass relation in our sample is consistent with being linear, with black hole to bulge ratio $\sim$ 0.03 %, similar to Wandel (1999) and Laor (1998, 2001) for low mass objects but significantly shifted from the relation of Magorrian et al. (1998) and McLure & Dunlop (2000).Comment: 11 pages, 7 figures, 1 table, accepted for publication in MNRA

Kinetic models of ion transport through a nanopore

Kinetic equations for the stationary state distribution function of ions moving through narrow pores are solved for a number of one-dimensional models of single ion transport. Ions move through pores of length $L$, under the action of a constant external field and of a concentration gradient. The interaction of single ions with the confining pore surface and with water molecules inside the pore are modelled by a Fokker-Planck term in the kinetic equation, or by uncorrelated collisions with thermalizing centres distributed along the pore. The temporary binding of ions to polar residues lining the pore is modelled by stopping traps or energy barriers. Analytic expressions for the stationary ion current through the pore are derived for several versions of the model, as functions of key physical parameters. In all cases, saturation of the current at high fields is predicted. Such simple models, for which results are analytic, may prove useful in the study of the current/voltage relations of ion channels through membranes

Exact Solution of Two-Species Ballistic Annihilation with General Pair-Reaction Probability

The reaction process $A+B->C$ is modelled for ballistic reactants on an infinite line with particle velocities $v_A=c$ and $v_B=-c$ and initially segregated conditions, i.e. all A particles to the left and all B particles to the right of the origin. Previous, models of ballistic annihilation have particles that always react on contact, i.e. pair-reaction probability $p=1$. The evolution of such systems are wholly determined by the initial distribution of particles and therefore do not have a stochastic dynamics. However, in this paper the generalisation is made to $p<1$, allowing particles to pass through each other without necessarily reacting. In this way, the A and B particle domains overlap to form a fluctuating, finite-sized reaction zone where the product C is created. Fluctuations are also included in the currents of A and B particles entering the overlap region, thereby inducing a stochastic motion of the reaction zone as a whole. These two types of fluctuations, in the reactions and particle currents, are characterised by the `intrinsic reaction rate', seen in a single system, and the `extrinsic reaction rate', seen in an average over many systems. The intrinsic and extrinsic behaviours are examined and compared to the case of isotropically diffusing reactants.Comment: 22 pages, 2 figures, typos correcte

Model of Enterpreneurship and Social-cultural and Market Orientation of Small Business Owners in Poland

In the development of SMEs in Poland crucial meaning is legislation, steadily adapted to EU regulations, especially to the European Charter for Small Enterprises. Research conducted in Poland by many authors provide data for doing so, to confirm the hypothesis that among small businesses a vital role in shaping their work situation did not continue to play the market mechanisms and orientations, but mainly socio-cultural factors.W rozwoju MŚP w Polsce podstawowe znaczenie mają również uregulowania prawne, systematycznie dostosowywane do regulacji unijnych, zwłaszcza zaś do Europejskiej Karty Małych Przedsiębiorstw. Badania prowadzone w Polsce przez wielu autorów dostarczają danych ku temu, by potwierdzić tezę, że wśród drobnych przedsiębiorców decydującą rolę w kształtowaniu ich sytuacji pracy odgrywają nadal nie mechanizmy i orientacje rynkowe, ale przede wszystkim czynniki społeczno-kulturowe

Psychological interventions countering misinformation in social media : a scoping review : research protocol

Introduction: Misinformation is a complex concept and its meaning can encompass several kinds of different phenomena. Liang Wu et el. consider a wide variety of online behavior as misinformation:1 unintentionally spreading false information, intentionally spreading false information, disseminating urban legends, sharing fake news, unverified information, and rumors, as well as crowdturfing, spamming, trolling, and propagating hate speech, or being involved in cyberbullying. The aim of this review is to address the following question: “What psychological interventions countering misinformation can be deployed on popular social media platforms (e.g. Twitter, Facebook)?". In order to address this question, we have designed a systematic scoping review procedure in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. 2,3 Effective measures of countering misinformation on social media are instrumental for facilitating and fostering reliable public conversation about political and social problems. Moreover, countering misinformation on social media platforms can be also considered a public health intervention, especially in the time of health emergencies, such as the COVID-19 pandemic. Methods and analysis: A scoping review is a modern, rigorous approach to synthesis science, developed among others by the Joanna Briggs Institute team. For data extractions, we plan to use the following databases: Embase, Scopus, and PubMed. For paper selection, eligibility criteria were defined