2,319 research outputs found
Accessing the nucleon transverse structure in inclusive deep inelastic scattering
We revisit the standard analysis of inclusive Deep Inelastic Scattering off
nucleons taking into account the fact that on-shell quarks cannot be present in
the final state, but they rather decay into hadrons - a process that can be
described in terms of suitable "jet" correlators. As a consequence, a spin-flip
term associated with the invariant mass of the produced hadrons is generated
non perturbatively and couples to the target's transversity distribution
function. In inclusive cross sections, this provides an hitherto neglected and
large contribution to the twist-3 part of the g2 structure function, that can
explain the discrepancy between recent calculations and fits of this quantity.
It also provides an extension of the Burkhardt-Cottingham sum rule, putting
constraints on the small-x behavior of the transversity function, as well as an
extension of the Efremov-Teryaev-Leader sum rule, suggesting a novel way to
measure the tensor charge of the proton.Comment: 10 pages, 3 figures. Extended discussion on small-x transversity
asymptotics. References adde
What can we learn from the breaking of the Wandzura-Wilczek relation?
We review the study the Wandzura-Wilczek relation for the structure function
g_2, with a particular attention on the connection with the framework of
Transverse Momentum Dependent factorization. We emphasize that the relation is
broken by two distinct twist-3 terms. In the light of these findings, we
clarify what can be deduced from the available experimental data on g_2, which
indicate a breaking of the order 20-40%, and how to individually measure the
twist-3 terms.Comment: Talk given by Alberto Accardi at "Spin structure at long distances,"
Jefferson Lab, March 12-13 200
Nuove testimonianze sul popolamento rurale nell’ager Mediolanensis. L’impianto rustico di Melzo, Cascina Mascheroni
During recent excavations for the construction of a methane pipeline in the territory of the municipality of Melzo, north-east of Milan, a small Roman structure was discovered. It probably had functional use and was part of a larger rural settlement, not identified by archaeological investigations. The discovery constitutes new evidence of Roman rural construction in the territory of ancient Mediolanum.Nel corso di recenti scavi per la realizzazione di un metanodotto nel territorio del comune di Melzo, a nord-est di Milano, è stato messo in luce un piccolo impianto di epoca romana, a probabile destinazione funzionale, verosimilmente parte di un insediamento rustico più ampio, non identificato dalle indagini archeologiche. La scoperta costituisce una nuova testimonianza relativa all’edilizia rurale romana nel territorio dell’antica Mediolanum
Asymmetries involving dihadron fragmentation functions: from DIS to e+e- annihilation
Using a model calculation of dihadron fragmentation functions, we fit the
spin asymmetry recently extracted by HERMES for the semi-inclusive pion pair
production in deep-inelastic scattering on a transversely polarized proton
target. By evolving the obtained dihadron fragmentation functions, we make
predictions for the correlation of the angular distributions of two pion pairs
produced in electron-positron annihilations at BELLE kinematics. Our study
shows that the combination of two-hadron inclusive deep-inelastic scattering
and electron-positron annihilation measurements can provide a valid alternative
to Collins effect for the extraction of the quark transversity distribution in
the nucleon.Comment: 11 pages, RevTeX style, 6 figures in eps forma
Scavi e ricerche a Calvatone romana: il “Quartiere degli Artigiani” (scavi 2005 - 2007)
The archaeological excavations – organized by the University of Milano in the years 2005-2007 – in the vicus of Calvatone-Bedriacum brought to the identification of a large building probably used to productive function and for this reason called “Craftsmen Quarter”. The excavations, still in progress, have found few small rooms, with no rich ornament, probably shops or stores.Le campagne di scavo condotte negli anni 2005-2007 nel vicus di Calvatone-Bedriacum dalla missione dell’Università degli Studi di Milano hanno portato all’individuazione di un vasto impianto edilizio probabilmente destinato a svolgere funzioni produttive e perciò ribattezzato “Quartiere degli Artigiani”. Gli scavi, ancora in corso, hanno finora messo in luce una serie di ambienti di modeste dimensioni, privi di finiture di lusso, forse utilizzati come botteghe o magazzini
Multiple biomarkers responses in Prochilodus lineatus allowed assessing changes in the water quality of Salado River basin (Santa Fe, Argentina)
This field study assessed water quality of Salado River basin by using a set of 2 biomarkers in the fish Prochilodus lineatus. Multiple biomarkers were measured, 3 including morphological indexes (condition factor, liver somatic index), hematological 4 (red and white blood cells) and biochemical (glucose, total protein and cholinesterase 5 activity) parameters. Besides, detoxication and oxidative stress markers (antioxidant 6 enzymes, lipid peroxidation) were measured in liver, gills and kidney. Despite water 7 quality assessment did not show marked differences among sites, biomarkers responses 8 indicate that fish are living under stressful environmental conditions. According to 9 multivariate analysis glucose, glutathione S-transferase activity, lipid peroxidation 10 levels and the count of white blood cells are key biomarkers to contribute to 11 discrimination of sites. So, we suggest use those biomarkers in future monitoring of 12 freshwater aquatic systems. 1 This field study assessed water quality of Salado River basin by using a set of 2 biomarkers in the fish Prochilodus lineatus. Multiple biomarkers were measured, 3 including morphological indexes (condition factor, liver somatic index), hematological 4 (red and white blood cells) and biochemical (glucose, total protein and cholinesterase 5 activity) parameters. Besides, detoxication and oxidative stress markers (antioxidant 6 enzymes, lipid peroxidation) were measured in liver, gills and kidney. Despite water 7 quality assessment did not show marked differences among sites, biomarkers responses 8 indicate that fish are living under stressful environmental conditions. According to 9 multivariate analysis glucose, glutathione S-transferase activity, lipid peroxidation 10 levels and the count of white blood cells are key biomarkers to contribute to 11 discrimination of sites. So, we suggest use those biomarkers in future monitoring of 12 freshwater aquatic systems.Fil: Cazenave, Jimena. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Santa Fe. Instituto Nacional de LimnologĂa. Universidad Nacional del Litoral. Instituto Nacional de LimnologĂa; ArgentinaFil: Bacchetta, Carla. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Santa Fe. Instituto Nacional de LimnologĂa. Universidad Nacional del Litoral. Instituto Nacional de LimnologĂa; ArgentinaFil: Parma, Maria Julieta E.. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Santa Fe. Instituto Nacional de LimnologĂa. Universidad Nacional del Litoral. Instituto Nacional de LimnologĂa; ArgentinaFil: Scarabotti, Pablo Augusto. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Santa Fe. Instituto Nacional de LimnologĂa. Universidad Nacional del Litoral. Instituto Nacional de LimnologĂa; ArgentinaFil: Wunderlin, Daniel Alberto. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico CĂłrdoba. Centro de Investigaciones en BioquĂmica ClĂnica e InmunologĂa; Argentin
Quark fragmentation as a probe of dynamical mass generation
We address the propagation and hadronization of a struck quark by studying
the gauge invariance of the color-averaged cut quark propagator, and by
relating this to the single inclusive quark fragmentation correlator by means
of new sum rules. Using suitable Wilson lines, we provide a gauge-invariant
definition for the mass of the color-averaged dressed quark and decompose this
into the sum of a current and an interaction-dependent component. The latter,
which we argue is an order parameter for dynamical chiral symmetry breaking,
also appears in the sum rule for the twist-3 fragmentation
function, providing a specific experimental way to probe the dynamical
generation of mass in Quantum Chromo Dynamics.Comment: published versio
Clinical heterogeneity and diagnostic delay of autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy syndrome
n/
Red Listing plants under full national responsibility: Extinction risk and threats in the vascular flora endemic to Italy
Taxa endemic to a country are key elements for setting national conservation priorities and for driving conservation
strategies, since their persistence is entirely dependent on national policy. We applied the IUCN Red
List categories to all Italian endemic vascular plants (1340 taxa) to assess their current risk of extinction and to
highlight their major threats. Our results revealed that six taxa are already extinct and that 22.4% (300 taxa) are
threatened with extinction, while 18.4% (247; especially belonging to apomictic groups) have been categorized
as Data Deficient. Italian endemic vascular plants are primarily threatened by natural habitat modification due
to agriculture, residential and tourism development. Taxa occurring in coastal areas and lowlands, where anthropogenic
impacts and habitat destruction are concentrated, display the greatest population decline and extinction.
The national network of protected areas could be considered effective in protecting endemic-rich areas (ERAs) and endemic taxa, but ineffective in protecting narrow endemic-rich areas (NERAs), accordingly changes
to the existing network may increase the effectiveness of protection. For the first time in the Mediterranean Basin
biodiversity hotspot, we present a comprehensive extinction assessment for endemic plants under the full responsibility
of a single country. This would provide an important step towards the prioritization and conservation
of threatened endemic flora at Italian, European, and Mediterranean level. A successful conservation
strategy of the Italian endemic vascular flora should implement the protected area system, solve some taxonomical
criticism in poorly known genera, and should rely on monitoring threatened species, and on developing
species-specific action plans
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