Transverse momentum versus multiplicity fluctuations in high-energy nuclear collisions

We discuss recently measured event-by-event fluctuations of transverse momentum and of multiplicity in relativistic heavy-ion collisions. It is shown that the non-monotonic behavior of the p_T-fluctuations as a function of collision centrality can be fully explained by the observed non-monotonic multiplicity fluctuations. A possible mechanism responsible for the multiplicity fluctuations is also considered.Comment: 5 pages, 3 figures, revised & extended, to appear in Phys. Rev.

Thermodynamics of MHD flows with axial symmetry

We present strategies based upon extremization principles, in the case of the axisymmetric equations of magnetohydrodynamics (MHD). We study the equilibrium shape by using a minimum energy principle under the constraints of the MHD axisymmetric equations. We also propose a numerical algorithm based on a maximum energy dissipation principle to compute in a consistent way the equilibrium states. Then, we develop the statistical mechanics of such flows and recover the same equilibrium states giving a justification of the minimum energy principle. We find that fluctuations obey a Gaussian shape and we make the link between the conservation of the Casimirs on the coarse-grained scale and the process of energy dissipation

Availability of long-acting and permanent family-planning methods leads to increase in use in conflict-affected northern Uganda: evidence from cross-sectional baseline and endline cluster surveys

Humanitarian assistance standards require specific attention to address the reproductive health (RH) needs of conflict-affected populations. Despite these internationally recognised standards, access to RH services is still often compromised in war. We assessed the effectiveness of our programme in northern Uganda to provide family planning (FP) services through mobile outreach and public health centre strengthening. Baseline (n=905) and endline (n=873) cross-sectional surveys using a multistage cluster sampling design were conducted in the catchment areas of four public health centres in 2007 and 2010. Current use of any modern FP method increased from 7.1% to 22.6% (adjusted odds ratio [OR] 3.34 [95% confidence interval (CI) 2.27–4.92]); current use of long-acting and permanent methods increased from 1.2% to 9.8% (adjusted OR 9.45 [95%CI 3.99–22.39]). The proportion of women with unmet need for FP decreased from 52.1% to 35.7%. This study demonstrates that when comprehensive FP services are provided among conflict-affected populations, women will choose to use them. The combination of mobile teams and health systems strengthening can make a full range of methods quickly available while supporting the health system to continue to provide those services in challenging and resource-constrained settings

Irreversible Performance of a Quantum Harmonic Heat Engine

The unavoidable irreversible losses of power in a heat engine are found to be of quantum origin. Following thermodynamic tradition a model quantum heat engine operating by the Otto cycle is analyzed. The working medium of the model is composed of an ensemble of harmonic oscillators. A link is established between the quantum observables and thermodynamical variables based on the concept of canonical invariance. These quantum variables are sufficient to determine the state of the system and with it all thermodynamical variables. Conditions for optimal work, power and entropy production show that maximum power is a compromise between the quasistatic limit of adiabatic following on the compression and expansion branches and a sudden limit of very short time allocation to these branches. At high temperatures and quasistatic operating conditions the efficiency at maximum power coincides with the endoreversible result. The optimal compression ratio varies from the square root of the temperature ratio in the quasistatic limit where their reversibility is dominated by heat conductance to the temperature ratio to the power of 1/4 in the sudden limit when the irreversibility is dominated by friction. When the engine deviates from adiabatic conditions the performance is subject to friction. The origin of this friction can be traced to the noncommutability of the kinetic and potential energy of the working medium.Comment: 25 pages, 7 figures. Revision added explicit heat-transfer expression and extended the discussion on the quantum origin of frictio

Relativistic Klein-Gordon charge effects by information-theoretic measures

The charge spreading of ground and excited states of Klein-Gordon particles moving in a Coulomb potential is quantitatively analyzed by means of the ordinary moments and the Heisenberg measure as well as by use of the most relevant information-theoretic measures of global (Shannon entropic power) and local (Fisher's information) types. The dependence of these complementary quantities on the nuclear charge Z and the quantum numbers characterizing the physical states is carefully discussed. The comparison of the relativistic Klein-Gordon and non-relativistic Schrodinger values is made. The non-relativistic limits at large principal quantum number n and for small values of Z are also reached.Comment: Accepted in New Journal of Physic

RNA sequencing supports distinct reactive oxygen species-mediated pathways of apoptosis by high and low size mass fractions of Bay leaf (Lauris nobilis) in HT-29 cells

Anti-proliferative and pro-apoptotic effects of Bay leaf (Laurus nobilis) in mammalian cancer and HT-29 adenocarcinoma cells have been previously attributed to effects of polyphenolic and essential oil chemical species. Recently, we demonstrated differentiated growth-regulating effects of high (HFBL) versus low molecular mass (LFBL) aqueous fractions of bay leaf and now confirm by comparative effects on gene expression, that HFBL and LFBL suppress HT-29 growth by distinct mechanisms. Induction of intra-cellular lesions including DNA strand breakage by extra-cellular HFBL, invoked the hypothesis that iron-mediated reactive oxygen species with capacity to penetrate cell membrane, were responsible for HFBL-mediated effects, supported by equivalent effects of HFBL in combination with γ radiation. Activities of HFBL and LFBL were interpreted to reflect differentiated responses to iron-mediated reactive oxygen species (ROS), occurring either outside or inside cells. In the presence of LFBL, apoptotic death was relatively delayed compared with HFBL. ROS production by LFBL mediated p53-dependent apoptosis and recovery was suppressed by promoting G1/S phase arrest and failure of cellular tight junctions. In comparison, intra-cellular anti-oxidant protection exerted by LFBL was absent for extra-cellular HFBL (likely polysaccharide-rich), which potentiated more rapid apoptosis by producing DNA double strand breaks. Differentiated effects on expression of genes regulating ROS defense and chromatic condensation by LFBL versus HFBL, were observed. The results support ferrous iron in cell culture systems and potentially in vivo, can invoke different extra-cellular versus intra-cellular ROS-mediated chemistries, that may be regulated by exogenous, including dietary species

Differential Effects of Antibiotic Therapy on the Structure and Function of Human Gut Microbiota

The human intestinal microbiota performs many essential functions for the host. Antimicrobial agents, such as antibiotics (AB), are also known to disturb microbial community equilibrium, thereby having an impact on human physiology. While an increasing number of studies investigate the effects of AB usage on changes in human gut microbiota biodiversity, its functional effects are still poorly understood. We performed a follow-up study to explore the effect of ABs with different modes of action on human gut microbiota composition and function. Four individuals were treated with different antibiotics and samples were taken before, during and after the AB course for all of them. Changes in the total and in the active (growing) microbiota as well as the functional changes were addressed by 16S rRNA gene and metagenomic 454-based pyrosequencing approaches. We have found that the class of antibiotic, particularly its antimicrobial effect and mode of action, played an important role in modulating the gut microbiota composition and function. Furthermore, analysis of the resistome suggested that oscillatory dynamics are not only due to antibiotic-target resistance, but also to fluctuations in the surviving bacterial community. Our results indicated that the effect of AB on the human gut microbiota relates to the interaction of several factors, principally the properties of the antimicrobial agent, and the structure, functions and resistance genes of the microbial community

Organization, Evolution, Cognition and Dynamic Capabilities

Using insights from ‘embodied cognition’ and a resulting ‘cognitive theory of the firm’, I aim to contribute to the further development of evolutionary theory of organizations, in the specification of organizations as ‘interactors’ that carry organizational competencies as ‘replicators’, within industries as ‘populations’. Especially, I analyze how, if at all, ‘dynamic capabilities’ can be fitted into evolutionary theory. I propose that the prime purpose of an organization is to serve as a cognitive ‘focusing device’. Here, cognition has a wide meaning, including perception, interpretation, sense making, and value judgements. I analyse how this yields organizations as cohesive wholes, and differences within and between industries. I propose the following sources of variation: replication in communication, novel combinations of existing knowledge, and a path of discovery by which exploitation leads to exploration. These yield a proposal for dynamic capabilities. I discuss in what sense, and to what extent these sources of variation are ‘blind’, as postulated in evolutionary theory.

The enchanted snake and the forbidden fruit: the ayahuasca ‘fairy tale’ tourist

This ethnographic study increases our understanding of Westerners seeking genuine fairy tale experiences of magic, transformation and enchantment within South American psychedelic ayahuasca tourism. Examining 63 tourists, this study shows how vision-based spirit sensegivers facilitate individuals in exorcising demons, to make sense of themselves as spiritual beings within an enchanted universe. However, and with this potion quickly wearing off upon returning to the West, tourists feel abandoned by their spirits, and disconnected from the fairy lands. Coupled with not wanting to re-experience intense inner tensions from stepping in and out of a fairy tale, further tourism is rejected. As such, ayahuasca tourism becomes a ‘forgotten’ fairy tale, rarely told