13,231 research outputs found
Is acting prosocially beneficial for the credit market?
This article argues that behaving prosocially implies more transparent information during the negotiation process of a financial contract and more cooperation among the parties to respect the terms of the contract. For this reason this work considers interest rate on loans and insolvency rate functions of prosocial behaviour along with the traditional socio-economic and financial collaterals. The context of study is Italy and the analysis is developed at a cross-regional level. We collect data from the two reports on âRelatives and Safety Netâ produced by the Italian Centre Bureau of Statistics (ISTAT) in 1998 and 2003 and from the reports on âRegional Economicsâ produced by the Bank of Italy in the same years. A two-period panel model shows two interesting outcomes. Firstly, regions with a higher proportion of prosocial individuals report lower interest rates on loans and insolvency rates. Secondly, when we include the efficiency of legal enforcement, evidence supports the idea that a more efficient legal framework can act as a more reliable transmission mechanism of institutional norms and facilitate the internalisation of social norms
The usefulness of c-Kit in the immunohistochemical assessment of melanocytic lesions
C-Kit (CD117), the receptor for the stem cell factor, a growth factor for melanocyte migra- tion and proliferation, has shown differential immunostaining in various benign and malig- nant melanocytic lesions. The purpose of this study is to compare c-Kit immunostaining in benign nevi and in primary and metastatic malignant melanomas, to determine whether c-Kit can aid in the differential diagnosis of these lesions. c-Kit immunostaining was per- formed in 60 cases of pigmented lesions, including 39 benign nevi (5 blue nevi, 5 intra- dermal nevi, 3 junctional nevi, 15 cases of pri- mary compound nevus, 11 cases of Spitz nevus), 18 cases of primary malignant melanoma and 3 cases of metastatic melanoma. The vast majority of nevi and melanomas examined in this study were posi- tive for c-Kit, with minimal differences between benign and malignant lesions. C-Kit cytoplasmatic immunoreactivity in the intraepidermal proliferating nevus cells, was detected in benign pigmented lesions as well as in malignant melanoma, increasing with the age of patients (P=0.007) in both groups. The patientâs age at presentation appeared to be the variable able to cluster benign and malignant pigmented lesions. The percentage of c-Kit positive intraepidermal nevus cells was better associated with age despite other vari- ables (P=0.014). The intensity and percentage of c-Kit positivity in the proliferating nevus cells in the dermis was significantly increased in malignant melanocytic lesions (P=0.015 and P=0.008) compared to benign lesions (compound melanocytic nevi, Spitz nevi, intradermal nevi, blue nevi). Immunostaning for c-Kit in metastatic melanomas was nega- tive. Interestingly in two cases of melanoma occurring on a pre-existent nevus, the melanoma tumor cells showed strong cytoplas- matic and membranous positivity for c-kit, in contrast with the absence of any immunoreac- tivity in pre-existent intradermal nevus cells. C-Kit does not appear to be a strong immuno- histochemical marker for distinguishing melanoma from melanocytic nevi, if we consid- er c-Kit expression in intraepidermal prolifer- ating cells. The c-Kit expression in proliferat- ing melanocytes in the dermis could help in the differential diagnosis between a superfi- cial spreading melanoma (with dermis inva- sion) and a compound nevus or an intradermal nevus. Finally, c-Kit could be a good diagnostic tool for distinguishing benign compound nevi from malignant melanocytic lesions with der- mis invasion and to differentiate metastatic melanoma from primary melanoma
GRB 970228 Within the EMBH Model
We consider the gamma-ray burst of 1997 February 28 (GRB 970228) within the
ElectroMagnetic Black Hole (EMBH) model. We first determine the value of the
two free parameters that characterize energetically the GRB phenomenon in the
EMBH model, that is to say the dyadosphere energy,
ergs, and the baryonic remnant mass in units of ,
. Having in this way estimated the
energy emitted during the beam-target phase, we evaluate the role of the
InterStellar Medium (ISM) number density (n) and of the ratio between the effective emitting area and the total surface area of the GRB
source, in reproducing the observed profiles of the GRB 970228 prompt emission
and X-ray (2-10 keV energy band) afterglow. The importance of the ISM
distribution three-dimensional treatment around the central black hole is also
stressed in this analysis.Comment: 4 pages, 1 figure, to appear in the Proceedings of the Los Alamos
"Gamma Ray Burst Symposium" in Santa Fe, New Mexico, September 8-12 2003 (AIP
Conf. Ser.), CHAPTER: GRB Connection to Supernova
Elliptic CMB Sky
The ellipticity of the anisotropy spots of the Cosmic Microwave Background
measured by the Wilkinson Microwave Anisotropy Probe (WMAP) has been studied.
We find an average ellipticity of about 2, confirming with a far larger
statistics similar results found first for the COBE-DMR CMB maps, and then for
the BOOMERanG CMB maps. There are no preferred directions for the obliquity of
the anisotropy spots. The average ellipticity is independent of temperature
threshold and is present on scales both smaller and larger than the horizon at
the last scattering. The measured ellipticity characteristics are consistent
with being the effect of geodesics mixing occurring in an hyperbolic Universe,
and can mark the emergence of CMB ellipticity as a new observable constant
describing the Universe. There is no way of simulating this effect. Therefore
we cannot exclude that the observed behavior of the measured ellipticity can
result from a trivial topology in the popular flat -CDM model, or from
a non-trivial topology.Comment: 10 pages, 5 figures, the version to appear in Mod.Phys.Lett.
Glassy magnetic behavior and correlation length in nanogranular Fe-oxide and Au/Fe-oxide samples
In nanoscale magnetic systems, the possible coexistence of structural disorder and competing magnetic interactionsmay determine the appearance of a glassy magnetic behavior, implying the onset of a low-temperature disordered collective state of frozen magnetic moments. This phenomenology is the object of an intense research activity, stimulated by a fundamental scientific interest and by the need to clarify how disordered magnetism effects may affect the performance of magnetic devices (e.g., sensors and data storage media). We report the results of a magnetic study that aims to broaden the basic knowledge of glassy magnetic systems and concerns the comparison between two samples, prepared by a polyol method. The first can be described as a nanogranular spinel Fe-oxide phase composed of ultrafine nanocrystallites (size of the order of 1 nm); in the second, the Fe-oxide phase incorporated non-magnetic Au nanoparticles (10-20 nm in size). In both samples, the Fe-oxide phase exhibits a glassy magnetic behavior and the nanocrystallite moments undergo a very similar freezing process. However, in the frozen regime, the Au/Fe-oxide composite sample is magnetically softer. This effect is explained by considering that the Au nanoparticles constitute physical constraints that limit the length of magnetic correlation between the frozen Fe-oxide moments
ATLAS RPC Quality Assurance results at INFN Lecce
The main results of the quality assurance tests performed on the Resistive
Plate Chamber used by the ATLAS experiment at LHC as muon trigger chambers are
reported and discussed.
Since July 2004, about 270 RPC units has been certified at INFN Lecce site
and delivered to CERN, for being integrated in the final muon station of the
ATLAS barrel region.
We show the key RPC characteristics which qualify the performance of this
detector technology as muon trigger chamber in the harsh LHC enviroments.
These are dark current, chamber efficiency, noise rate, gas volume
tomography, and gas leakage.Comment: Comments: 6 pages, 1 table, 9 figures Proceedings of XXV Physics in
Collision-Prague, Czech Republic, 6-9 July 200
Immunoreactivity for alpha-smooth muscle actin characterizes a potentially aggressive subgroup of little basal cell carcinomas
Basal cell carcinoma (BCC) is a very common malignant skin tumor that rarely metastatizes, but is often locally aggressive. Several factors, like large size (more than 3 cm), exposure to ultraviolet rays, histological variants, level of infiltration and perineural or perivascular invasion, are associated with a more aggressive clinical course. These morphological features seem to be more determinant in mideface localized BCC, which frequently show a significantly higher recurrence rate. An immunohistochemical profile, characterized by reactivity of tumor cells for p53, Ki67 and alpha-SMA has been associated with a more aggressive behaviour in large BCCs. The aim of this study was to verify if also little (<3 cm) basal cell carcinomas can express immunohistochemical markers typical for an aggressive behaviour
Unanswered Questions in the Electroweak Theory
This article is devoted to the status of the electroweak theory on the eve of
experimentation at CERN's Large Hadron Collider. A compact summary of the logic
and structure of the electroweak theory precedes an examination of what
experimental tests have established so far. The outstanding unconfirmed
prediction of the electroweak theory is the existence of the Higgs boson, a
weakly interacting spin-zero particle that is the agent of electroweak symmetry
breaking, the giver of mass to the weak gauge bosons, the quarks, and the
leptons. General arguments imply that the Higgs boson or other new physics is
required on the TeV energy scale. Indirect constraints from global analyses of
electroweak measurements suggest that the mass of the standard-model Higgs
boson is less than 200 GeV. Once its mass is assumed, the properties of the
Higgs boson follow from the electroweak theory, and these inform the search for
the Higgs boson. Alternative mechanisms for electroweak symmetry breaking are
reviewed, and the importance of electroweak symmetry breaking is illuminated by
considering a world without a specific mechanism to hide the electroweak
symmetry.
For all its triumphs, the electroweak theory has many shortcomings. . . .Comment: 31 pages, 20 figures; prepared for Annual Review of Nuclear and
Particle Science (minor changes
WMAP confirming the ellipticity in BOOMERanG and COBE CMB maps
The recent study of BOOMERanG 150 GHz Cosmic Microwave Background (CMB)
radiation maps have detected ellipticity of the temperature anisotropy spots
independent on the temperature threshold. The effect has been found for spots
up to several degrees in size, where the biases of the ellipticity estimator
and of the noise are small. To check the effect, now we have studied, with the
same algorithm and in the same sky region, the WMAP maps. We find ellipticity
of the same average value also in WMAP maps, despite of the different
sensitivity of the two experiments to low multipoles. Large spot elongations
had been detected also for the COBE-DMR maps. If this effect is due to geodesic
mixing and hence due to non precisely zero curvature of the hyperbolic
Universe, it can be linked to the origin of WMAP low multipoles anomaly.Comment: More explanations and two references adde
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