Features of Fast Neutrons in Dark Matter Searches

Diffractive scattering of "fast" or "high energy" neutrons, can give low energy nuclear recoils in the signal region for dark matter searches. We present a discussion using the 'black disc' model. This permits a simple and general, although approximate, description of this possible background. We note a number of its features. In particular there are mass number A dependent aspects which can be studied in setups where events on different nuclei are observable at the same time. These include the recoil energy distributions, and the A behavior of the cross section. We define a parameter $E^o_R$ which characterizes the recoil energy to be expected due to fast neutrons. It ranges from 100 keV on light nuclei to a few keV on heavy nuclei, and a general treatment is possible in terms of it, within the 'black disc' approximation. In addition, the presence of inelastic processes would be characteristic of fast neutrons.Comment: new version with numerous small corrections and clarifications. Improved figures and references. No essential changes in conten

Measuring the Temperature of a Mesoscopic Quantum Electron System by means of Single Electron Statistics

We measure the temperature of a mesoscopic system consisting of an ultra-dilute two dimensional electron gas at the $Si/SiO_2$ interface in a metal-oxide-semiconductor field effect transistor (MOSFET) quantum dot by means of the capture and emission of an electron in a point defect close to the interface. Contrarily to previous reports, we show that the capture and emission by point defects in Si n-MOSFETs can be temperature dependent down to 800 mK. As the finite quantum grand canonical ensemble model applies, the time domain charge fluctuation in the defect is used to determine the temperature of the few electron gas in the channel.Comment: 4 Figures (color

Entangling macroscopic diamonds at room temperature: Bounds on the continuous-spontaneous-localization parameters

A recent experiment [K. C. Lee et al., Science 334, 1253 (2011)] succeeded in detecting entanglement between two macroscopic specks of diamonds, separated by a macroscopic distance, at room temperature. This impressive results is a further confirmation of the validity of quantum theory in (at least parts of) the mesoscopic and macroscopic domain, and poses a challenge to collapse models, which predict a violation of the quantum superposition principle, which is the bigger the larger the system. We analyze the experiment in the light of such models. We will show that the bounds placed by experimental data are weaker than those coming from matter-wave interferometry and non-interferometric tests of collapse models.Comment: 7 pages, 3 figures, v2: close to the published version, LaTe

Financial maturity concepts with application to three hardwood timber stands

Timber is “financially mature” when its rate of value increase falls below what the landowner can earn in alternative investments that are comparable in duration, risk, liquidity, and other factors. The basic concept of financial maturity is simple, but in application it involves several very important, basic questions and issues

Ultrastructural aspects of two different mast cell populations in human healthy gingival tissue

The results of our recent microscopy studies clearly have demonstrated the constant presence of numerous metachromatic cells in healthy human gingival connective tissue. Despite the great number of studies on mast cell population in many human organs (lung, skin, uterus, and bowel), at the present time few are the studies regarding the morphostructural aspects of mast cells in the human gingiva. The aim of this study was to assess by transmission electron microscopy the presence of mast cells in the healthy human gingiva and to characterize the ultrastructural aspects of mast cells populations. 30 specimens of human gingival tissue were collected from 30 patients with informed consent. The samples were prepared for T.E.M. examination. In all the ultrathin sections observed we detected numerous and ubiquitarious mast cells. These exhibited several morphological types of cytoplasmic granules with characteristic subgranular architectural variety in shape and density. This allowed us to divide mast cells into two groups: cells with granules consisted of compact coiled scrolls, fine granular material and lattice - grating configuration, and cells containing granules with discrete scrolls formed by more concentric lamellae and particulate structure. The two ultrastructural aspects observed correspond to McTC and McT of the international literature. Therefore in the human gingival connective tissue, like in other organs, two types of mast cells are clearly present. Surprisingly, the human gingival tissue shows, like the lung, McT as the prevailing subpopulation, in contrast to the skin, uterus and gastrointestinal submucosa where McTC prevail. Dans le cadre d’une étude sur la population cellulaire du tissu conjonctif gingival humain nous avons constaté, en microscopie optique, la présence constante de nombreuses cellules metachromatiques. Pour définir la nature de telles cellules et pour en déterminer les aspects ultra-structuraux, nous avons étudié au microscope électronique à transmission 30 biopsies du tissu gingival humain, cliniquement sain. Dans tous les échantillons examinés nous avons observé de nombreux mastocytes dont le contenu granulaire nous est apparu caractérisé par un aspect « à particules » et « en rouleaux » ou bien, dans d’autres éléments cellulaires, par un aspect «en grillage». Les deux aspects ultrastructuraux décrits nous permettent de distinguer les mastocytes gingivaux en deux sous-populations, différentes comme l’ont confirmé plusieurs auteurs, selon la localisation anatomique, selon la structure intérieure et le contenu enzymatique des granules, et, enfin, selon la réaction à des substances sécrétagogues

Fireballs Loading and the Blast Wave Model of Gamma Ray Bursts

A simple function for the spectral power $P(\epsilon,t) \equiv \nu L(\nu)$ is proposed to model, with 9 parameters, the spectral and temporal evolution of the observed nonthermal synchrotron power flux from GRBs in the blast wave model. Here $\epsilon = h\nu/$m$_e$c$^2$ is the observed dimensionless photon energy and $t$ is the observing time. Assumptions and an issue of lack of self-consistency are spelled out. The spectra are found to be most sensitive to the baryon loading, expressed in terms of the initial bulk Lorentz factor $\Gamma_0$, and an equipartition term $q$ which is assumed to be constant in time and independent of $\Gamma_0$. Expressions are given for the peak spectral power $P_p(t) = P(\epsilon_p,t)$ at the photon energy $\epsilon = \epsilon_p(t)$ of the spectral power peak. A general rule is that the total fireball particle kinetic energy $E_0 \sim \Pi_0 t_d$, where $t_d \propto \Gamma_0^{-8/3}$ is the deceleration time scale and $\Pi_0 \equiv P(\epsilon_p,t_d) \propto \Gamma_0^{8/3}$ is the maximum measured bolometric power output in radiation, during which it is carried primarily by photons with energy ${\cal E}_0 = \epsilon_p(t_d) \propto q\Gamma_0^4$.Comment: 26 pages, including 4 figures, uses epsf.sty, rotate.sty; submitted to ApJ; revised version with extended introduction, redrawn figures, and correction

Response of CdWO4 crystal scintillator for few MeV ions and low energy electrons

The response of a CdWO4 crystal scintillator to protons, alpha particles, Li, C, O and Ti ions with energies in the range 1 - 10 MeV was measured. The non-proportionality of CdWO4 for low energy electrons (4 - 110 keV) was studied with the Compton Coincidence Technique. The energy dependence of the quenching factors for ions and the relative light yield for low energy electrons was calculated using a semi-empirical approach. Pulse-shape discrimination ability between gamma quanta, protons, alpha particles and ions was investigated.Comment: 20 pages, 8 figs, accepted in Nucl. Instrum. Meth.

Hida Scan in The Follow-Up of Biliary-Enteric Anastomoses

In order to assess the patency and function of biliary-enteric anastomoses performed in our Department of Surgery, 21 patients entered the following study, provided an informed consent was obtained. All the patients were affected by benign biliary tract diseases and underwent either Roux-en-Y hepaticojejunostomy (11 cases), or side-to-side choledochoduodenostomy (10 cases). The 21 patients were evaluated with Tc-99m-HIDA scanning at intervals of 20 days–36 months after the surgical procedure (mean 14 months). The images were obtained after intravenous injection of the radioactive medium (5 mCi) and the scans were taken at 1 min (1 frame/s), 3 min (1 frame/10 s), and 56 min (1 frame/2 min). The data were analyzed by a Digital PDP 11/34 Computer System. This method allowed us to assess each individual patient for the patency of the anastomosis and, by computer analysis, to build up a profile of the timing of the passage of the radioactive medium through the anastomosis; a delayed passage across the anastomosis was always pathological

Correlating densities of centrality and activities in cities : the cases of Bologna (IT) and Barcelona (ES)

This paper examines the relationship between street centrality and densities of commercial and service activities in cities. The aim is to verify whether a correlation exists and whether some 'secondary' activities, i.e. those scarcely specialized oriented to the general public and ordinary daily life, are more linked to street centrality than others. The metropolitan area of Barcelona (Spain) is investigated, and results are compared with those found in a previous work on the city of Bologna (Italy). Street centrality is calibrated in a multiple centrality assessment (MCA) model composed of multiple measures such as closeness, betweenness and straightness. Kernel density estimation (KDE) is used to transform data sets of centrality and activities to one scale unit for correlation analysis between them. Results indicate that retail and service activities in both Bologna and Barcelona tend to concentrate in areas with better centralities, and that secondary activities exhibit a higher correlation