4,317 research outputs found
Excitation Spectrum and Correlation Functions of the Z_3-Chiral Potts Quantum Spin Chain
We study the excitation spectrum and the correlation functions of the Z_3-
chiral Potts model in the massive high-temperature phase using perturbation
expansions and numerical diagonalization. We are mainly interested in results
for general chiral angles but we consider also the superintegrable case. For
the parameter values considered, we find that the band structure of the low-
lying part of the excitation spectrum has the form expected from a
quasiparticle picture with two fundamental particles. Studying the N-dependence
of the spectrum, we confirm the stability of the second fundamental particle in
a limited range of the momentum, even when its energy becomes so high that it
lies very high up among the multiparticle scattering states. This is not a
phenomenon restricted to the superintegrable line. Calculating a
non-translationally invariant correlation function, we give evidence that it is
oscillating. Within our numerical accuracy we find a relation between the
oscillation length and the dip position of the momentum dispersion of the
lightest particle which seems to be quite independent of the chiral angles.Comment: 19 pages + 6 PostScript figures (LaTeX); BONN-TH-94-2
Analysis of side writing asymmetry
The side writing asymmetry of a recording head was investigated using an overwrite configuration that enhances the edge effects. The track profiles of the overwrite patterns were measured for analyzing the side writing performance of the head. Magnetic force microscope (MFM) images of the overwrite patterns were studied using fast Fourier transforms (FFT), and they confirmed the profiling results. We measured weak edge effects at good pole alignment. The experiments were performed with metal evaporated (ME) and metal particle (MP) tapes having magnetic layers between 50 and 300 nm
Thermodynamics of the 3-State Potts Spin Chain
We demonstrate the relation of the infrared anomaly of conformal field theory
with entropy considerations of finite temperature thermodynamics for the
3-state Potts chain. We compute the free energy and compute the low temperature
specific heat for both the ferromagnetic and anti-ferromagnetic spin chains,
and find the central charges for both.Comment: 18 pages, LaTex. Preprint # ITP-SB-92-60. References added and first
section expande
Analyticity and Integrabiity in the Chiral Potts Model
We study the perturbation theory for the general non-integrable chiral Potts
model depending on two chiral angles and a strength parameter and show how the
analyticity of the ground state energy and correlation functions dramatically
increases when the angles and the strength parameter satisfy the integrability
condition. We further specialize to the superintegrable case and verify that a
sum rule is obeyed.Comment: 31 pages in harvmac including 9 tables, several misprints eliminate
model as effective Hamiltonian for generalized Hubbard models with broken -symmetry
We consider the limit of strong Coulomb attraction for generalized Hubbard
models with -symmetry. In this limit these models are equivalent to the
ferromagnetic spin-1/2 Heisenberg quantum spin chain. In order to study the
behaviour of the superconducting phase in the electronic model under
perturbations which break the -symmetry we investigate the ground state
of the ferromagnetic non-critical -chain in the sector with fixed
magnetization. It turns out to be a large bound state of magnons. We find
that the perturbations considered here lead to the disappearance of the
off-diagonal longe-range order.Comment: Results of previous version are generalized, new title, references
added. 10 pages, Latex, no figure
Detection and Quantification of Grass and Olea Airborne Pollen Allergens in Outdoor Air Samples and its Correlation with Pollen Counts
Detection and Quantification of Grass and Olea Airborne Pollen Allergens in Outdoor Air Samples and its Correlation with Pollen Counts
R Ferro1*, R Ribeiro1*, MR Martins1,2, AT Caldeira1,3, E Caeiro6, CM Antunes1,5
& R Brandão2,4 and the HIALINE working group7
1Dep. of Chemistry, University of Evora, Portugal;
2Mediterranean Inst. Crop and Environment Sciences, Univ.Evora, Portugal;
3Centro Química, University of Évora, Portugal;
4Dep. Biology, University of Evora;
5Center for NeuroSciences and Cell Biology-University of Coimbra, Portugal;
6Soc.Portuguesa Alergol.Imunologia Clínica , Portugal
7 M. Thibaudon, France, M. Smith, United Kingdom, C. Galan, Spain R. Albertini, Italy, L. Grewling, Poland, G. Reese, Germany, A. Rantio-Lehtimäki, Finland, S. Jäger and U. Berger, Austria, M. Sofiev, Finland, I. Sauliene, Lithuania, L. Cecchi, Italy
Presenting author: [email protected] tel: +351 266760889
Introduction: Allergic respiratory diseases broken out after an exposure to airborne pollen, as asthma and allergic rhinitis, are deeply increasing and they represent one of the major public health problems nowadays, affecting about 40% of European population. In Portugal, grass and Olea europaea pollen are certainly one of the main sources of athmospheric aeroallergens and as such, one of the main causes of respiratory allergy.
For these reasons, it is useful the development of new strategies for prevention and treatment of these pathologies. The execution of aerobiological analysis including pollen calendars and/or immunoassays for the detection and quantification of allergens which could forecast the allergenic potential of the athmosphere are quite relevant since they would contribute to develop prevention measures of allergic respiratory diseases. The aim of this study was to evaluate the putative correlation between the concentration of some of the major allergens of and with their pollen counts.
Methodology: On a meteorological platform at the town center of Evora (south Portugal), ambient air was sampled at 800L/min with a Chemvol high-volume cascade impactor equipped with stages PM>10µm, 10 µm>PM>2.5µm. The polyurethane impacting substrate was extracted with 0.1M NH4HCO3, pH8.1, supplemented with 0.1% BSA. The major pollen allergens from grass Phleum p 5 and olive Ole e 1 were determined with allergen specific ELISA´s. Airborne pollen of and Olea europaea simultaneously monitored with a Burkard Seven Day Recording Volumetric Spore Trap* , between the 30th of April and the 8th of July of 2009. Both samplers were placed side-by-side with air input at the same level.
Results: During the pollen season of 2009, high values of grass pollen were recorded between May 2th and June 1 th. It was also observed that the air content of Phl p5 or Ole e1 aeroallergens were directly correlated with airborne pollen counts of Poaceae and Oleaceae, respectively.
Conclusions: These results suggest that the directly quantification of aeroallergens may contribute, together with pollen counts of air samples, to define the allergic risk with higher precision.
Acknowledgments: This study is integrated in the european project HIALINE (Executive Agency for Health and Consumers under grant agreement No 2008 11 07
Completeness of the Bethe Ansatz solution of the open XXZ chain with nondiagonal boundary terms
A Bethe Ansatz solution of the open spin-1/2 XXZ quantum spin chain with
nondiagonal boundary terms has recently been proposed. Using a numerical
procedure developed by McCoy et al., we find significant evidence that this
solution can yield the complete set of eigenvalues for generic values of the
bulk and boundary parameters satisfying one linear relation. Moreover, our
results suggest that this solution is practical for investigating the ground
state of this model in the thermodynamic limit.Comment: 15 pages, LaTeX; amssymb, amsmath, no figures, 5 tables; v2 contains
an additional footnote and a "Note Added"; v3 contains an Addendu
Risk factors of overweight and obesity among preschool children with different ethnic background
partially_open5noIn this study, we evaluated the risk factors associated with overweight and obesity in 2,640 preschool children in Italy taking into account the ethnic background of the parents. Height and weight were measured and BMI was calculated. Personal and lifestyle data for the children (birth weight, type of breastfeeding, sleep duration, skipping breakfast, snacking, physical activity) and parents (ethnicity, educational level, occupation, weight, height) were collected by means of a questionnaire. Italian and Other European children generally showed the highest percentage of normal weight, while the other ethnic groups presented a greater imbalance. Overweight and obesity were high in African males, who also presented high birth weight. Breastfeeding was most common, although formula feeding was significantly higher in Italians than in immigrants. Immigrants, particularly males, tended to skip breakfast more than Italians. Physical activity was significantly higher in Italians than in immigrants. In the parents, underweight was particularly high in Italian and Other mothers. African parents had high rates of overweight and obesity and a low educational level. The most common profession was worker for the fathers and housewife for the mothers, with the exception of Italians in which clerical work prevailed. Multiple linear regression analysis showed that the BMI of children was closely related to the BMI of the parents and the birth weight. Hence, these are the most informative parameters in preventing obesity.openToselli S; Zaccagni L; Celenza F; Albertini A; Gualdi-Russo EToselli, S; Zaccagni, Luciana; Celenza, F; Albertini, A; Gualdi, Emanuel
Predictive value of hematological and phenotypical parameters on postchemotherapy leukocyte recovery
Background: Grade IV chemotherapy toxicity is defined as absolute neutrophil count <500/μL. The nadir is considered as the lowest neutrophil number following chemotherapy, and generally is not expected before the 7th day from the start of chemotherapy. The usual prophylactic dose of rHu-G-CSF (Filgrastim) is 300 μg/day, starting 24-48 h after chemotherapy until hematological recovery. However, individual patient response is largely variable, so that rHu-G-CSF doses can be different. The aim of this study was to verify if peripheral blood automated flow cytochemistry and flow cytometry analysis may be helpful in predicting the individual response and saving rHu-G-CSF. Methods: During Grade IV neutropenia, blood counts from 30 cancer patients were analyzed daily by ADVIA 120 automated flow cytochemistry analyzer and by Facscalibur flow cytometer till the nadir. "Large unstained cells" (LUCs), myeloperoxidase index (MPXI), blasts, and various cell subpopulations in the peripheral blood were studied. At nadir rHu-G-CSF was started and 81 chemotherapy cycles were analyzed. Cycles were stratified according to their number and to two dose-levels of rHuG-CSF needed to recovery (300-600 vs. 900-1200 μg) and analyzed in relation to mean values of MPXI and mean absolute number of LUCs in the nadir phase. The linear regressions of LUCs % over time in relation to two dose-levels of rHu-G-CSF and uni-multivariate analysis of lymphocyte subpopulations, CD34+ cells, MPXI, and blasts were also performed. Results: In the nadir phase, the increase of MPXI above the upper limit of normality (>10; median 27.7), characterized a slow hematological recovery. MPXI levels were directly related to the cycle number and inversely related to the absolute number of LUCs and CD34 +/CD45+ cells. A faster hematological recovery was associated with a higher LUC increase per day (0.56% vs. 0.25%), higher blast (median 36.7/μL vs. 19.5/μL) and CD34+/CD45+ cell (median 2.2/μL vs. 0.82/μL) counts. Conclusions: Our study showed that some biological indicators such as MPXI, LUCs, blasts, and CD34 +/CD45+ cells may be of clinical relevance in predicting individual hematological response to rHu-G-CSF. Special attention should be paid when nadir MPXI exceeds the upper limit of normality because the hematological recovery may be delayed. © 2009 Clinical Cytometry Society
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