The resistible effects of Coulomb interaction on nucleus-vapor phase coexistence

We explore the effects of Coulomb interaction upon the nuclear liquid vapor phase transition. Because large nuclei (A>60) are metastable objects, phases, phase coexistence, and phase transitions cannot be defined with any generality and the analogy to liquid vapor is ill-posed for these heavy systems. However, it is possible to account for the Coulomb interaction in the decay rates and obtain the coexistence phase diagram for the corresponding uncharged system.Comment: 5 pages, 5 figure

Modeling a Slicer Mirror Using Zemax User-Defined Surface

A slicer mirror is a complex surface composed by many tilted and decentered mirrors sub-surfaces. The major difficulty to model such a complex surface is the large number of parameters used to define it. The Zemax's multi-configuration mode is usually used to specify each parameters (tilts, curvatures, decenters) for each mirror sub-surface which are then considered independently. Otherwise making use of the User-Defined Surface (UDS-DLL) Zemax capability, we are able to consider the set of sub-surfaces as a whole surface. In this paper, we present such a UDS-DLL tool comparing its performance with those of the classical multi-configuration mode. In particular, we explore the use of UDS-DLL to investigate the cross-talk due to the diffraction on the slicer array mirrors which has been a burden task when using multi-configuration mode.Comment: Submitted to the proceedings of the Durham Integral Field Spectroscopy Workshop July 4th-8th 200

Compound nuclear decay and the liquid to vapor phase transition: a physical picture

Analyses of multifragmentation in terms of the Fisher droplet model (FDM) and the associated construction of a nuclear phase diagram bring forth the problem of the actual existence of the nuclear vapor phase and the meaning of its associated pressure. We present here a physical picture of fragment production from excited nuclei that solves this problem and establishes the relationship between the FDM and the standard compound nucleus decay rate for rare particles emitted in first-chance decay. The compound thermal emission picture is formally equivalent to a FDM-like equilibrium description and avoids the problem of the vapor while also explaining the observation of Boltzmann-like distribution of emission times. In this picture a simple Fermi gas thermometric relation is naturally justified and verified in the fragment yields and time scales. Low energy compound nucleus fragment yields scale according to the FDM and lead to an estimate of the infinite symmetric nuclear matter critical temperature between 18 and 27 MeV depending on the choice of the surface energy coefficient of nuclear matter.Comment: Five page two column pages, four figures, submitted to Phys. Rev.

New Wrinkles on an Old Model: Correlation Between Liquid Drop Parameters and Curvature Term

The relationship between the volume and surface energy coefficients in the liquid drop A^{-1/3} expansion of nuclear masses is discussed. The volume and surface coefficients in the liquid drop expansion share the same physical origin and their physical connection is used to extend the expansion with a curvature term. A possible generalization of the Wigner term is also suggested. This connection between coefficients is used to fit the experimental nuclear masses. The excellent fit obtained with a smaller number of parameters validates the assumed physical connection.Comment: 6 pages, 2 figure

Exploring supply chain finance along different supply chain stages: a case-based research in the agri-food industry

PurposeSince 2008's financial crisis, attention toward supply chain finance (SCF) has increased. However, most research investigates SCF considering single supply chain (SC) stages or buyer-supplier dyads and focuses on a single SCF solution. It is important to see how different solutions are adopted at different SC stages, by actors with different financing needs. This study aims to analyze SCF at different SC stages, to understand why different solutions are implemented at different SC stages and the contingency factors (regulation, SC stage, product category and size) influencing their adoption. Design/methodology/approachThe paper is based on multiple exploratory case studies in the Italian agri-food industry, considering firms distributed at different SC stages and adopting multiple SCF solutions. The paper exploits a contingent approach (Sousa and Voss, 2008) to analyze how contingent factors influence SCF adoption at different SC stages. FindingsFindings explain how and why different SC stages (producer, cooperative, processor and retailer) implement different SCF solutions (reverse factoring, dynamic discounting, inventory finance and Minibond), describing contingency variables' impact on their adoption. Originality/valueTo the best of the authors' knowledge, the research is original in its description of SCF at different SC stages, considering different SC actors' drivers and barriers, and questioning the importance of a coordinated approach in SCF adoption along an entire SC. Moreover, the paper adopts a contingent approach, contributing to SCF research, seldomly based on theoretical lenses

The reproductive system of Opisthogonimus philodryadum (West, 1896) (Digenea)

O sistema reprodutor do adulto de Opisthogonimus philodryadum(West, 1896) foi estudado anatomica e histologicamente ao microscópio. Esta análise mostra que o canal de Laurer, metratermo, cirro e duto ejaculatório possuem um epitélio aprofundado. 0 metratermo e a franja citoplasmática do cirro ou tectum tem uma camada esclerótica diferenciada, semelhante em aspecto e cor às dos espinhos do tegumento do animal

TSPAN5 IS A KEY PLAYER IN DENDRITIC SPINES FORMATION AND AMPA RECEPTORS RECYCLING

TSPAN5 is a brain enriched protein member of the tetraspanin superfamily, a group of transmembrane proteins some of which have been shown to fundamentally regulate the development of mammalian nervous system. This class of proteins presents the peculiar ability to clusterize forming specialized membrane region called Tetraspanin Enriched Microdomains (TEMs) where they can accumulate other proteins. We found that in developing neurons TSPAN5 was mainly present at the surface membrane while it was concentrated in an intracellular compartment in the postsynapse of mature neurons. We hypothesized that these different localisations could be due to different functions. To deepen the first function of the protein, we knocked down the expression of the protein and found that this led to a dramatic reduction in the number of dendritic spines. We, thus, hypothesized that TSPAN5, through the formation of TEMs, could be responsible of dendritic spines formation. We observed in differential lysis of developing rat hippocampal neurons that two proteins, fundamental for dendritic spines formation, Neuroligin-1 and GluA2 AMPA receptor subunit, were associated with TSPAN5 TEMs. We found that the knockdown of TSPAN5 led to increased mobility of Neuroligin-1 and GluA2 AMPA receptors suggesting the loss of clusterization typical of the first moments of spines formation. To understand the second function of TSPAN5 we identified AP-4 complex as an interactor of the C-terminal intracellular tail of TSPAN5. This complex is known to act on AMPARs trafficking through direct binding of Stargazin, an AMPARs auxiliary subunit. We observed that the knockdown of TSPAN5, carried out after the majority of the synaptogenesis was occurred, caused a strong decrease in surface and total level of GluA2. Different evidences suggested an involvement of TSPAN5 in vesicular transport of GluA2 and we demonstrated that TSPAN5 was necessary for the correct recycling of this receptor. These results highlight multiple roles of TSPAN5 in the regulation of both synapse formation and synaptic functioning in mammalian brain through two distinct mechanisms of action

Classification of life by the mechanism of genome size evolution

The classification of life should be based upon the fundamental mechanism in the evolution of life. We found that the global relationships among species should be circular phylogeny, which is quite different from the common sense based upon phylogenetic trees. The genealogical circles can be observed clearly according to the analysis of protein length distributions of contemporary species. Thus, we suggest that domains can be defined by distinguished phylogenetic circles, which are global and stable characteristics of living systems. The mechanism in genome size evolution has been clarified; hence main component questions on C-value enigma can be explained. According to the correlations and quasi-periodicity of protein length distributions, we can also classify life into three domains.Comment: 53 pages, 9 figures, 2 table

Simulation of cellular irradiation with the CENBG microbeam line using GEANT4

Light-ion microbeams provide a unique opportunity to irradiate biological samples at the cellular level and to investigate radiobiological effects at low doses of high LET ionising radiation. Since 1998 a single-ion irradiation facility has been developed on the focused horizontal microbeam line of the CENBG 3.5 MV Van de Graaff accelerator. This setup delivers in air single protons and alpha particles of a few MeV onto cultured cells, with a spatial resolution of a few microns, allowing subcellular targeting. In this paper, we present results from the use of the GEANT4 toolkit to simulate cellular irradiation with the CENBG microbeam line, from the entrance to the microprobe up to the cellular medium.Comment: 6 pages, 8 figures, presented at the 2003 IEEE-NSS conference, Portland, OR, USA, October 20-24, 200