1,944 research outputs found
First Observation of the Hadronic Transition ΄(4S)âηhb(1P) and New Measurement of the hb(1P) and ηb(1S) Parameters
Using a sample of 771.6Ă106 ΄΄(4S) decays collected by the Belle experiment at the KEKB e+eâ collider, we observe, for the first time, the transition ΄(4S)âηhb(1P) with the branching fraction B[΄(4S)âηhb(1P)]=(2.18±0.11±0.18)Ă10â3 and we measure the hb(1P) mass Mhb(1P)=(9899.3±0.4±1.0)ââMeV/c2, corresponding to the hyperfine (HF) splitting ÎMHF(1P)=(0.6±0.4±1.0)ââMeV/c2. Using the transition hb(1P)âγηb(1S), we measure the ηb(1S) mass Mηb(1S)=(9400.7±1.7±1.6)ââMeV/c2, corresponding to ÎMHF(1S)=(59.6±1.7±1.6)ââMeV/c2, the ηb(1S) width Îηb(1S)=(8+6â5±5)ââMeV/c2 and the branching fraction B[hb(1P)âγηb(1S)]=(56±8±4)%
X-ray fluorescence analysis of trace elements in silicate rocks using fused glass discs
X-ray fluorescence analysis of twelve trace elements in silicate rocks (V, Cr, Co, Ni, Rb, Sr, Y, Zr, Nb, Ba, La, Ce) was carried out by using fused glass discs prepared by mixing 0.700 g of powder rock samples with 3.150 g of lithium tetraborate and 3.150 g of lithium metaborate. The method was calibrated using one hundred and twenty-one in-house rock standards and the accuracy was tested using sixteen international rock standards. The errors range from 3 to 10% for abundances ranging from 0 to 2300 ppm. Overall, the quality of the analytical data obtained by the proposed method is similar to that one obtained by processing powder pellets. Since the samples prepared through this technique allows the determination of major elements too, with a high degree of accuracy, the proposed methodology is characterized by an excellent ratio of analytical quality and operating time
Automated taxonomy building by adopting discriminant and characteristic capabilities
Taxonomies are becoming essential in several fields, playing an important role in a large number of applications, particularly for specific domains. Taxonomies provide efficient tools to people by organizing a huge amount of information into a small hierarchical structure. Taxonomies were originally built by hand, but nowadays the technology permits to produce a vast amount of information. Consequently, recent research activities have been focused on automated taxonomy generation. In this paper, we propose a novel approach for automatically build a taxonomy, starting from a set of categories. We deem that, in a hierarchical structure, each node should intuitively be represented with proper meaningful and discriminant features, instead of considering a fixed feature space. Our proposal relies on two metrics able to identify the most meaningful features. Our conjecture is that a feature could significantly change its discriminant power (hence, its role) along the taxonomy levels. Hence, we devise a greedy algorithm able to build a taxonomy by identifying the meaningful terms for each level. We perform preliminary experiments that give rise to the usefulness of the proposed approach
Calibration of XRF data on silicate rocks using chemicals as in-house standards
X-ray fluorescence (XRF) is an accurate, rapid spectroscopic technique for chemical element determinations on rock samples. The aim of this research was to evaluate a calibration method based on the use of suitable mixtures of chemicals. X-ray fluorescence analysis of major elements (Na, Mg, Al, Si, K, Ca, Fe) was carried out using sample-lithium borate fusion mixtures (with a 1:9 sample/borate dilution). The accuracy of the proposed calibration method was tested on twenty-four international rock standards. Results are in good or excellent agreement with the literature recommended value
Inclusive study of bottomonium production in association with an η meson in e+eâ annihilations near ΄(5S)
We study bottomonium production in association with an η meson in e+eâ annihilations near the ΄(5S), at a center of mass energy of sâ=10.866GeV. The results are based on the 121.4fbâ1 data sample collected by the Belle experiment at the asymmetric energy KEKB collider. Only the η meson is reconstructed and the missing-mass spectrum of η candidates is investigated. We observe the e+eââη΄J(1D) process and find evidence for the e+eââη΄(2S) process, while no significant signals of ΄(1S), hb(1P), nor hb(2P) are found. Cross sections for the studied processes are reported
A fast and user-friendly software for quantitative chemical analysis through XRF
X-ray fluorescence (XRF) spectroscopy is a technique widely used for the study and
conservation of cultural heritage materials. A Microsoft Excel spreadsheet to determine major
(Na, Mg, Al, Si, K, Ca, Fe) and minor (P, Ti, Mn) elements in rocks and other materials by
XRF is presented. The code is based on the analytical method proposed a few decades ago by
Franzini et al., which is based on the algorithm: Ci = Ii â
ÎŁKi,j Cj, where Ci is the concentration
(expressed as wt%) of the chemical element âiâ, Ii is the intensity of the characteristic line, Cj is
the concentration of interfering elements, and Ki,j are experimental coefficients that account for
the matrix effects (absorption and enhancement). Ki,j have the dimension of mass absorption
coefficients and they may be calculated from a set of N reference samples using multivariate
regression methods. The algorithm proposed by these authors is particularly suitable for
processing samples prepared in the form of pressed powders. The Microsoft Excel spreadsheet
allows you to: a) choose a set of reference samples (international or interlaboratory standards);
b) evaluate the expected matrix effects on the basis of the XRF total mass absorption
coefficients; c) calculate the correction coefficients Ki,j through multivariable regression; d)
calculate the analytical accuracy and graphically represent the results; e) choose five samples
(monitors) for the correction of instrumental drift. Based on these steps, the software allows
you to: i) enter the analytical intensities of major and minor elements measured on the monitors
and on unknown samples (the loss on ignition must be determined separately); ii) calculate the
correction of the instrumental drift; iii) determine the concentration of elements and express
them as wt%
Aggiornamenti sulle infezioni da protozoi negli ovini della Sardegna
The aim of the present study was to deepened knowledge on epidemiology and taxonomy of Cryptosporidiosis, Sarcocystosis and Giardiosis in Sardinian dairy sheep.
Cryptosporidiosis was evaluated with microscopical and biomolecular methods in faecal samples from three different categories of sheep (lambs, pregnant sheep, post-partum sheep). Oocysts were found in 10.1% of examined animals, in 16.4% of lambs, in 7.2% of pregnant sheep and in 6.6% of post-partum sheep. Molecular characterization revealed the presence of two different species, Cryptosporidium parvum and C. ubiquitum. Within C. parvum were found the subtypes IIaA15G2R1 and IIdA20G1 while the subtype XIIa was isolated for C. ubiquitum.
Giardiosis was evaluated in the same sheep population, and Giardia cyst were microscopically detected in 6.6% of monitored farms, only in lambs. Molecular characterization of samples allow to identify the Assemblage AI of Giardia duodenalis.
Sarcosporidiosis was investigated with a cross sectional study on macroscopic and microscopic sarcocysts in Sardinian sheep at abattoirs. Macroscopic Sarcocystis spp. were found in 23.3% of examined muscles. Two different morphotypes were identified: large oval cysts, identified as Sarcocystis gigantea by molecular characterization, and slender fusiform cysts, identified as S. medusiformis. Microscopic cysts were detected in 77.7% of examined heart samples, molecular analysis allow to identify the species S. tenella (95.5%) and S. arieticanis (17.8%)
Spin effects in Bottomonium at Belle
Spin effects have a dominant role in the understanding of the dynamic of the Bottomonium system, both in the transitions and in the correlation among light hadrons being produced in their annihilation. Naively we expect a suppression of the transitions with spin flipping terms, but recent results on h transitions from i(4S) and i(5S) challenge this approach. The most recent results from Belle on this field will help to clarify the role of the spin in the modeling of the singleand two-meson transitions. Besides this the Belle collaboration is performing an extensive series of studies on baryon production in bottomonium decays, meant to address the two-baryon correlation in i(1S) annihilation and the precise measurement of hyperon inclusive production rates in e + e collision. The search for the long sought H dibaryon is part of this effort
Panchina Calcarenite: A Building Material from Tuscany Coast
The âPanchinaâ calcarenite widely outcrops along the Tuscan coastline from Livorno
to Baratti (western Tuscany). It is a stone, highly porous with medium sized grains rich in
organogenic carbonate fragments, mainly consisting in shells of bivalves, gastropods, and
echinoderms visible to the naked eye or by using a lens. In the framework of the ongoing research
on the building stones and mortars used throughout the Middle Ages in and surrounding the
Pisaâs city (western Tuscany), this study focuses on the determination of the main physical and
mechanical properties of âPanchinaâ stone samples from Livorno coast (Tuscany, Italy). The
âPanchinaâ stone is no longer quarried and data is collected from unweathered rocks sampled
from currently accessible outcrops. The data collected on twenty-eightsamples from six outcrops
of the Tuscan coast showed that the analysed specimens are made up of abundant calcite,
subordinate quartz and feldspars, and traces of phyllosilicates. The analysed samples are
characterized by medium-high porosity, highly variable water absorption by both capillarity and
total immersion at atmospheric pressure, low uniaxial compressive resistance. Thanks to the
good physical and mechanical properties that characterize the stone, the âPanchinaâ calcarenite
is easy to work and extensively used in the necropolis of the Gulf of Baratti since Etruscan times
and, in medieval times, in various public and religious buildings in the city of Pisa
- âŠ