366 research outputs found
Hadronic Total Cross-sections Through Soft Gluon Summation in Impact Parameter Space
The Bloch-Nordsieck model for the parton distribution of hadrons in impact
parameter space, constructed using soft gluon summation, is investigated in
detail.
Its dependence upon the infrared structure of the strong coupling constant
is discussed, both for finite as well as singular, but integrable,
. The formalism is applied to the prediction of total proton-proton
and proton-antiproton cross-sections, where screening, due to soft gluon
emission from the initial valence quarks, becomes evident.Comment: 20 pages, Latex2e, input FEYNMAN,12 postscipt figures. Submitted to
PR
Multiparametric Porous Silicon Sensors
We investigated the possibility of using several sensing parameters from porous silicon in order to improve gas selectivity. By fabricating porous silicon optical microcavities, three independent quantities can be measured, i.e. the electrical conductance, the photoluminescence intensity, and the wavelength of the optical resonance. We monitored the change of these three parameters as a function of NO2 (0.5-5 ppm), ethanol (300-15000 ppm) and relative humidity (0-100%). Preliminary results confirm that the examined species affect the parameters in a different way, both as a relative change and as dynamic
On the jet spectrum in nucleus-nucleus interactions
We derive the inclusive transverse spectrum of minijets in nuclear collisions
at very high energies by assuming that the nuclear S-matrix factorizes into a
product of elastic S-matrices for elementary partonic collisions. Interference
effects and, in particular, the contribution of loop diagrams are fully taken
into account in the derivation of the spectrum, which is shown to coincide with
the result earlier obtained by superposing the elementary interactions
incoherently. A quantitative analysis confirms that the deformation induced by
multiple collsions is a large effect at RHIC and LHC energies, for transverse
momenta ~ 20 GeV.Comment: text in LaTex, 4 figures in P
Soft gluon radiation and energy dependence of total hadronic cross-sections
An impact parameter representation for soft gluon radiation is applied to
obtain both the initial decrease of the total cross-section ()
for proton-proton collisions as well as the later rise of with
energy for both and . The non-perturbative soft part of the
eikonal includes only limited low energy gluon emission and leads to the
initial decrease in the proton-proton cross- section. On the other hand, the
rapid rise in the hard, perturbative jet part of the eikonal is tamed into the
experimentally observed mild increase by soft gluon radiation whose maximum
energy rises slowly with energy.Comment: 30 pages, 6 figures. Version accepted for publication in Physical
Review D. Additional section with explanatory material added making the paper
more self contained and two figures changed to have a complete summary of the
available accelerator dat
Total photoproduction cross-section at very high energy
In this paper we apply to photoproduction total cross-section a model we have
proposed for purely hadronic processes and which is based on QCD mini-jets and
soft gluon re-summation. We compare the predictions of our model with the HERA
data as well as with other models. For cosmic rays, our model predicts
substantially higher cross-sections at TeV energies than models based on
factorization but lower than models based on mini-jets alone, without soft
gluons. We discuss the origin of this difference.Comment: 13 pages, 9 figures. Accepted for publication in EPJC. Changes
concern added references, clarifications of the Soft Gluon Resummation method
used in the paper, and other changes requested by the Journal referee which
do not change the results of the original versio
A dimensional approach to the psychopathology of migrants: a cross-sectional matched sample study
Objectives
Moving to a foreign country, whether out of necessity, seeking refuge, opportunity or mere curiosity, makes the individual more vulnerable to mental disorders. Even in the same conditions, many factors contribute to make migrants more susceptible to this risk than the
natives. Among many, these include linguistic and cultural differences. Unfortunately, these differences lead to a higher frequency of ‘not otherwise specified’ diagnoses in this part of the population. This limitation can lead to greater difficulties in therapeutic choices and epidemiological assessments. This study aims to enhance the clinician’s resources by testing a
trans-diagnostic, dimensional, psychopathological approach in the assessment of a group of migrants and a control group of natives referred to a psychiatric outpatient service.
Methods
The two groups of patients were matched for gender, age, categorical diagnosis and level of clinical severity. The SVARAD scale was used for the dimensional assessment, diagnoses were assigned according to DSM IV-TR criteria.
Results
A total of n = 224 patients, including cases (n = 112) and controls (n = 112), were recruited and agreed to participate in the study. The dimensions somatization, obsessiveness, and activation showed a significant difference between groups (p = .018; .011; .004, respectively).
Given the same degree of severity and the same diagnosis, migrants with mental disorders showed less activation and greater somatization.
Conclusions
Cross-cultural aspects and language differences, as well as the same social status of “migrant”, are certainly implicated in these differences. By taking these dimensional aspects into
account, clinicians could achieve greater precision in the diagnostic process and determine a significant change in the care of this risk group
Charge Collection Dynamics of the ARCADIA Passive Pixel Arrays: Laser Characterization and TCAD Modeling
Monolithic Active Pixel Sensors (MAPS) represent one of the most promising technologies for the next generation of radiation detectors. The ARCADIA project aims at the development of Fully Depleted (FD) MAPS employing a production process compatible with a 110 nm commercial CMOS technology. The first engineering run of the project included matrices of active pixels with embedded analog and digital frontend electronics and passive test structures such as passive pixel arrays, MOS capacitors and backside diodes. Although the produced samples were already characterized from the electrical point of view, a thorough study of the charge collection dynamics of the passive pixel arrays was still missing. In this paper we show the results of the dynamic characterization of a group of passive pixel arrays with different pixel pitches (50, 25 and 10 μm) and different pixel layouts. The tested samples have been illuminated from the backside with an infrared and a red laser with wavelengths equal to 1,060 nm and 660 nm, respectively. The pixel arrays have been mounted on a custom readout PCB connected to an external amplifier with 1 GHz bandwidth and the signals have been acquired through a fast digital oscilloscope. We employed both focused and unfocused laser spots to evaluate the change in the measured signal as a function of the laser spot position and the average response of the pixel arrays. An excellent agreement has been demonstrated by comparing the measured signals with the results of transient TCAD simulations and a time for 50% charge collection of 7.8, 4.2 and 2.6 ns has been predicted and experimentally validated in pixels with 50, 25 and 10 μm pitch, respectively
Comparison of cerebellar grey matter alterations in bipolar and cerebellar patients: evidence from Voxel-based analysis
The aim of this study was to compare the patterns of cerebellar alterations associated with bipolar disease with those induced by the presence of cerebellar neurodegenerative pathologies to clarify the potential cerebellar contribution to bipolar affective disturbance. Twenty-nine patients affected by bipolar disorder, 32 subjects affected by cerebellar neurodegenerative pathologies, and 37 age-matched healthy subjects underwent a 3T MRI protocol. A voxel-based morphometry analysis was used to show similarities and differences in cerebellar grey matter (GM) loss between the groups. We found a pattern of GM cerebellar alterations in both bipolar and cerebellar groups that involved the anterior and posterior cerebellar regions (p = 0.05). The direct comparison between bipolar and cerebellar patients demonstrated a significant difference in GM loss in cerebellar neurodegenerative patients in the bilateral anterior and posterior motor cerebellar regions, such as lobules I-IV, V, VI, VIIIa, VIIIb, IX, VIIb and vermis VI, while a pattern of overlapping GM loss was evident in right lobule V, right crus I and bilateral crus II. Our findings showed, for the first time, common and different alteration patterns of specific cerebellar lobules in bipolar and neurodegenerative cerebellar patients, which allows us to hypothesize a cerebellar role in cognitive and mood dysregulation symptoms that characterize bipolar disorde
Forward Physics at the LHC (Elba 2010)
The papers review the main theoretical and experimental aspects of the
Forward Physics at the Large Hadron Collider
Theory of mind profile and cerebellar alterations in remitted bipolar disorder 1 and 2: a comparison study
The literature on social cognition abilities in bipolar disorder (BD) is controversial about the occurrence of theory of mind (ToM) alterations. In addition to other cerebral structures, such as the frontal and limbic areas, the processing of socially relevant stimuli has also been attributed to the cerebellum, which has been demonstrated to be involved in the abovementioned disorder. Nevertheless, the cerebellar contribution to ToM deficits in bipolar patients needs to be elucidated further. To this aim, two tests assessing different components of ToM were used to evaluate the ability to appreciate affective and mental states of others in 17 individuals with a diagnosis of BD type 1 (BD1) and 13 with BD type 2 (BD2), both in the euthymic phase, compared to healthy matched controls. Cerebellar grey matter (GM) volumes were extracted and compared between BD1 and controls and BD2 and controls by using voxel-based morphometry. The results showed that BD1 patients were compromised in the cognitive and advanced components of ToM, while the BD2 ToM profile resulted in a more widespread compromise, also involving affective and automatic components. Both overlapping and differing areas of cerebellar GM reduction were found. The two groups of patients presented a pattern of GM reduction in cerebellar portions that are known to be involved in the affective and social domains, such as the vermis and Crus I and Crus II. Interestingly, in both BD1 and BD2, positive correlations were detected between lower ToM scores and decreased volumes in the cerebellum. Overall, BD2 patients showed a more compromised ToM profile and greater cerebellar impairment than BD1 patients. The different pattern of structural abnormalities may account for the different ToM performances evidenced, thus leading to divergent profiles between BD1 and BD2
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