790 research outputs found
The flare origin of Forbush decreases not associated with solar flares on the visible hemisphere of the Sun
Investigations have shown that Forbush decreases (Fds) are produced by the propagation into the interplanetary space of a strong perturbation originating from a solar flare (Sf) accompanied by Type IV radioemission. As the front of the perturbation propagates into the interplanetary space, the region in which the galactic cosmic rays are modulated (Fd-modulated region) rotates westward with the Sun and is generally included between two boundary streams; therefore the Fds not associated with observed type IV Sfs (N.Ass.Fds) are likely to be produced by type IV Sfs occurred on the Sun's backside: these vents can be observed when the Earth crosses the corotating Western boundary of the modulated region
Anomalous short-term increases in the galactic cosmic ray intensity: Are they related to the interplanetary magnetic cloud-like structures?
Thirty-one short-term increases (time duration 24 hours and amplitude up to 5%) in the galactic cosmic ray intensity, occurring inside Forbush decreases events, have been identified over the period 1966 - 1977. These increases are highly anisotropic and occur after the compression region following the shock; the interplanetary medium is characterized by intense ( 10 nT) and higly fluctuating magnetic field B, high velocity, low density and temperature (flare ejecta piston?). These B-fluctuations seem to be ordered variations which could be representative of magnetic clouds. Also the large cosmic ray increase occurring on 17-18 September 1979, belongs to this category of events
Suggestions for improving the efficiency of ground-based neutron monitors for detecting solar neutrons
On the occasion of the June 3, 1982 intense gamma-ray solar flare a significant increase in counting rate due to solar neutrons was observed by the neutron monitors of Junsfraujoch and Lomnicky Stit located at middle latitudes and high altitudes. In spite of a larger detector employed and of the smaller solar zenith angle, the amplitude of the same event observed at Rome was much smaller and the statistical fluctuations of the salactic cosmic ray background higher than the ones registered at the two mountain stations, because of the greater atmospheric depth at which the Rome monitor is located. The effeciency for detecting a solar neutron event by a NM-64 monitor as a function of the Sun zenith angle, atmospheric depth and threshold rigidity of the station was studied
Effect of continuum couplings in fusion of halo Be on Pb around the Coulomb barrier
The effect of continuum couplings in the fusion of the halo nucleus Be
on Pb around the Coulomb barrier is studied using a three-body model
within a coupled discretised continuum channels (CDCC) formalism. We
investigate in particular the role of continuum-continuum couplings. These are
found to hinder total, complete and incomplete fusion processes. Couplings to
the projectile bound excited state redistribute the complete and
incomplete fusion cross sections, but the total fusion cross section remains
nearly constant. Results show that continuum-continuum couplings enhance the
irreversibility of breakup and reduce the flux that penetrates the Coulomb
barrier. Converged total fusion cross sections agree with the experimental ones
for energies around the Coulomb barrier, but underestimate those for energies
well above the Coulomb barrier.Comment: 15 pages, 7 figures, accepted in Phys. Rev.
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Detection and isolation of circulating tumor cells with single-cell resolution: A successful lab-on-a-chip device
This paper was presented at the 3rd Micro and Nano Flows Conference (MNF2011), which was held at the Makedonia Palace Hotel, Thessaloniki in Greece. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, Aristotle University of Thessaloniki, University of Thessaly, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute.This paper presents the unique features of DEPArray™ an automated system enabling image-based cell sorting with single-cell resolution and describes its potential application in the field of oncology
A Machine Learning Approach to Monitor the Emergence of Late Intrauterine Growth Restriction
Late intrauterine growth restriction (IUGR) is a fetal pathological condition characterized by chronic hypoxia secondary to placental insufficiency, resulting in an abnormal rate of fetal growth. This pathology has been associated with increased fetal and neonatal morbidity and mortality. In standard clinical practice, late IUGR diagnosis can only be suspected in the third trimester and ultimately confirmed at birth. This study presents a radial basis function support vector machine (RBF-SVM) classification based on quantitative features extracted from fetal heart rate (FHR) signals acquired using routine cardiotocography (CTG) in a population of 160 healthy and 102 late IUGR fetuses. First, the individual performance of each time, frequency, and nonlinear feature was tested. To improve the unsatisfactory results of univariate analysis we firstly adopted a Recursive Feature Elimination approach to select the best subset of FHR-based parameters contributing to the discrimination of healthy vs. late IUGR fetuses. A fine tuning of the RBF-SVM model parameters resulted in a satisfactory classification performance in the training set (accuracy 0.93, sensitivity 0.93, specificity 0.84). Comparable results were obtained when applying the model on a totally independent testing set. This investigation supports the use of a multivariate approach for the in utero identification of late IUGR condition based on quantitative FHR features encompassing different domains. The proposed model allows describing the relationships among features beyond the traditional linear approaches, thus improving the classification performance. This framework has the potential to be proposed as a screening tool for the identification of late IUGR fetuses
Breakup of F on Pb near the Coulomb barrier
Angular distributions of oxygen produced in the breakup of F incident
on a Pb target have been measured around the grazing angle at beam
energies of 98 and 120 MeV. The data are dominated by the proton stripping
mechanism and are well reproduced by dynamical calculations. The measured
breakup cross section is approximately a factor of 3 less than that of fusion
at 98 MeV. The influence of breakup on fusion is discussed.Comment: 7 pages, 8 figure
Fusion versus Breakup: Observation of Large Fusion Suppression for ^9Be + ^{208}Pb
Complete fusion excitation functions for Be + Pb have been
measured to high precision at near barrier energies. The experimental fusion
barrier distribution extracted from these data allows reliable prediction of
the expected complete fusion cross-sections. However, the measured
cross-sections are only 68% of those predicted. The large cross-sections
observed for incomplete fusion products support the interpretation that this
suppression of fusion is caused by Be breaking up into charged fragments
before reaching the fusion barrier. Implications for the fusion of radioactive
nuclei are discussed.Comment: RevTex, 11 pages, 2 postscript figures, to appear in PR
A vaccine using Anaplasma marginale subdominant type IV secretion system recombinant proteins was not protective against a virulent challenge
Anaplasma marginale is the most prevalent tick-borne livestock pathogen with worldwide distribution. Bovine anaplasmosis is a significant threat to cattle industry. Anaplasmosis outbreaks in endemic areas are prevented via vaccination with live A. centrale produced in splenectomized calves. Since A. centrale live vaccine can carry other pathogens and cause disease in adult cattle, research efforts are directed to develop safe recombinant subunit vaccines. Previous work found that the subdominant proteins of A. marginale type IV secretion system (T4SS) and the subdominant elongation factor-Tu (Ef-Tu) were involved in the protective immunity against the experimental challenge in cattle immunized with the A. marginale outer membrane (OM). This study evaluated the immunogenicity and protection conferred by recombinant VirB9.1, VirB9.2, VirB10, VirB11, and Ef-Tu proteins cloned and expressed in E. coli. Twenty steers were randomly clustered into four groups (G) of five animals each. Cattle from G1 and G2 were immunized with a mixture of 50 μg of each recombinant protein with Quil A® or Montanide™ adjuvants, respectively. Cattle from G3 and G4 (controls) were immunized with Quil A and Montanide adjuvants, respectively. Cattle received four immunizations at three-week intervals and were challenged with 107 A. marginale-parasitized erythrocytes 42 days after the fourth immunization. After challenge, all cattle showed clinical signs, with a significant drop of packed cell volume and a significant increase of parasitized erythrocytes (p<0.05), requiring treatment with oxytetracycline to prevent death. The levels of IgG2 induced in the immunized groups did not correlate with the observed lack of protection. Additional strategies are required to evaluate the role of these proteins and their potential utility in the development of effective vaccines.EEA RafaelaFil: Sarli, Macarena. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Novoa, María Belen. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Mazzucco, Matilde N. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; Argentina.Fil: Signorini, Marcelo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Echaide, Ignacio Eduardo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; Argentina.Fil: Echaide, Susana T. de. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; Argentina.Fil: Primo, María Evangelina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
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