Specific heat and high-temperature series of lattice models: interpolation scheme and examples on quantum spin systems in one and two dimensions

We have developed a new method for evaluating the specific heat of lattice spin systems. It is based on the knowledge of high-temperature series expansions, the total entropy of the system and the low-temperature expected behavior of the specific heat as well as the ground-state energy. By the choice of an appropriate variable (entropy as a function of energy), a stable interpolation scheme between low and high temperature is performed. Contrary to previous methods, the constraint that the total entropy is log(2S+1) for a spin S on each site is automatically satisfied. We present some applications to quantum spin models on one- and two- dimensional lattices. Remarkably, in most cases, a good accuracy is obtained down to zero temperature.Comment: 10 pages (RevTeX 4) including 11 eps figures. To appear in Phys. Rev.

Low temperature expansion for the 3-d Ising Model

We compute the weak coupling expansion for the energy of the three dimensional Ising model through 48 excited bonds. We also compute the magnetization through 40 excited bonds. This was achieved via a recursive enumeration of states of fixed energy on a set of finite lattices. We use a linear combination of lattices with a generalization of helical boundary conditions to eliminate finite volume effects.Comment: 10 pages, IASSNS-HEP-92/42, BNL-4767

Evaluation of the ESBL-coding plasmids transmissibility in E. coli isolated from ambulatory patient's urina

Representatives of the Enterobacteriaceae family are the main causative agents of urinary tract infections. Escherichia coli can exhibit resistance to [beta] -lactam antibiotics by synthesizing ESBL (extended spectrum [beta]-lactamases). CTX-M [beta] -lactamases are the dominant group of ESBL. In this paper, we investigated the ability of E. coli urinary isolates to transmit resistance genes within the plasmid. An analysis of the effectiveness of conjugation has shown that E. coli strains producing ESBL are capable of transferring resistance genes to a recipient bacterium at a high frequency

Series studies of the Potts model. I: The simple cubic Ising model

The finite lattice method of series expansion is generalised to the $q$-state Potts model on the simple cubic lattice. It is found that the computational effort grows exponentially with the square of the number of series terms obtained, unlike two-dimensional lattices where the computational requirements grow exponentially with the number of terms. For the Ising ($q=2$) case we have extended low-temperature series for the partition functions, magnetisation and zero-field susceptibility to $u^{26}$ from $u^{20}$. The high-temperature series for the zero-field partition function is extended from $v^{18}$ to $v^{22}$. Subsequent analysis gives critical exponents in agreement with those from field theory.Comment: submitted to J. Phys. A: Math. Gen. Uses preprint.sty: included. 24 page

Recording electrical activity from the brain of behaving octopus

: Octopuses, which are among the most intelligent invertebrates,1,2,3,4 have no skeleton and eight flexible arms whose sensory and motor activities are at once autonomous and coordinated by a complex central nervous system.5,6,7,8 The octopus brain contains a very large number of neurons, organized into numerous distinct lobes, the functions of which have been proposed based largely on the results of lesioning experiments.9,10,11,12,13 In other species, linking brain activity to behavior is done by implanting electrodes and directly correlating electrical activity with observed animal behavior. However, because the octopus lacks any hard structure to which recording equipment can be anchored, and because it uses its eight flexible arms to remove any foreign object attached to the outside of its body, in vivo recording of electrical activity from untethered, behaving octopuses has thus far not been possible. Here, we describe a novel technique for inserting a portable data logger into the octopus and implanting electrodes into the vertical lobe system, such that brain activity can be recorded for up to 12 h from unanesthetized, untethered octopuses and can be synchronized with simultaneous video recordings of behavior. In the brain activity, we identified several distinct patterns that appeared consistently in all animals. While some resemble activity patterns in mammalian neural tissue, others, such as episodes of 2 Hz, large amplitude oscillations, have not been reported. By providing an experimental platform for recording brain activity in behaving octopuses, our study is a critical step toward understanding how the brain controls behavior in these remarkable animals

Foundation and empire : a critique of Hardt and Negri

In this article, Thompson complements recent critiques of Hardt and Negri's Empire (see Finn Bowring in Capital and Class, no. 83) using the tools of labour process theory to critique the political economy of Empire, and to note its unfortunate similarities to conventional theories of the knowledge economy

Impact of the council of europe resolution on quality and safety assurance requirements for medicinal products prepared in pharmacies for the special needs of patients

Introduction and objective: The regulation of pharmacy preparations, especially for standards for quality assurance and safety, is not harmonised across Europe and falls under the national competencies of individual states. There are concerns about quality control and safety for the medicinal products made in pharmacies, which is widespread in European countries. There are, however, good reasons to continue this practice, which is able to tailor preparations to the specific needs of a particular patient or patient group and to provide a supplementary source of supply when an industrially manufactured product, which is authorised for marketing is not available or when there are temporary shortages of licensed medicines. In seeking to provide guidelines for legislation and acting on the advice of an expert group dealing in pharmaceutical practices, the Committee of Ministers of the Council of Europe passed a resolution in 2011. The Council of Europe Resolution provides authorities and pharmacists with the means to reinforce safety measures for medicinal products prepared in pharmacies and to harmonise quality assurance and safety standards. It dealt with aspects of pharmacy preparation such as quality standards for preparation and distribution, marketing authorisation, product dossiers, labelling, reporting, and safety. In 2013 and 2014 the Committee of Experts carried out a survey to evaluate the impact of the resolution within a cross section of member states,Methods: In the resolution of 2011 the member states were recommended to adapt their legislation in line with its provisions. The survey that was carried out in 2013 and 2014 followed the recommendations in the reso-lution. A questionnaire was made and sent to across section of member states.Results: Among the member states involved, the results of this survey show a clear commitment to imple-ment the recommendations of the resolution.Conclusions: This report presents the results of the survey with a discussion of outstanding issues

The synaptic ribbon is critical for sound encoding at high rates and with temporal precision.

We studied the role of the synaptic ribbon for sound encoding at the synapses between inner hair cells (IHCs) and spiral ganglion neurons (SGNs) in mice lacking RIBEYE (RBEKO/KO). Electron and immunofluorescence microscopy revealed a lack of synaptic ribbons and an assembly of several small active zones (AZs) at each synaptic contact. Spontaneous and sound-evoked firing rates of SGNs and their compound action potential were reduced, indicating impaired transmission at ribbonless IHC-SGN synapses. The temporal precision of sound encoding was impaired and the recovery of SGN-firing from adaptation indicated slowed synaptic vesicle (SV) replenishment. Activation of Ca2+-channels was shifted to more depolarized potentials and exocytosis was reduced for weak depolarizations. Presynaptic Ca2+-signals showed a broader spread, compatible with the altered Ca2+-channel clustering observed by super-resolution immunofluorescence microscopy. We postulate that RIBEYE disruption is partially compensated by multi-AZ organization. The remaining synaptic deficit indicates ribbon function in SV-replenishment and Ca2+-channel regulation

Kondo Effect in a Metal with Correlated Conduction Electrons: Diagrammatic Approach

We study the low-temperature behavior of a magnetic impurity which is weakly coupled to correlated conduction electrons. To account for conduction electron interactions a diagrammatic approach in the frame of the 1/N expansion is developed. The method allows us to study various consequences of the conduction electron correlations for the ground state and the low-energy excitations. We analyse the characteristic energy scale in the limit of weak conduction electron interactions. Results are reported for static properties (impurity valence, charge susceptibility, magnetic susceptibility, and specific heat) in the low-temperature limit.Comment: 16 pages, 9 figure

Low Temperature Expansions for Potts Models

On simple cubic lattices, we compute low temperature series expansions for the energy, magnetization and susceptibility of the three-state Potts model in D=2 and D=3 to 45 and 39 excited bonds respectively, and the eight-state Potts model in D=2 to 25 excited bonds. We use a recursive procedure which enumerates states explicitly. We analyze the series using Dlog Pade analysis and inhomogeneous differential approximants.Comment: (17 pages + 8 figures