859 research outputs found
Electrodeposited CoNiFeP soft-magnetic films for high-frequency applications
peer-reviewedWe have studied the influence of P and of plating current density on static/dynamic magnetic and electrical properties of CoNiFe high moment alloy. We found that morphology, electrical and magnetic properties of films with P content up to 10 at. % are quite different from those of pure CoNiFe. CoNiFeP morphology consists of a structure made of isolated islands with sizes varying between 10 and 50 Όm. We indirectly obtained resistivity in this structure by using high-frequency magnetic measurements. Film composition is weakly dependent on plating current density for values larger than 10 mA cm-2. Coercivities increase up to 6400 A m-1 and magnetization saturation is reduced to 1.0 T in CoNiFeP films. The most remarkable effect of P addition to CoNiFe is the increase of resistivity over two order of magnitude with values of 5.2 x10[power]-5Ωm compared to 2.4 x10[power]-7Ωm of pure CoNiFe.We also found that the ferromagnetic resonance of CoNiFeP alloy is 3 GHz for sample with 10 at. % P and a performance factor (BF) of ~4x10[power]5 Ts-1, which is a better performance than bulk ferrite
Drift-free humanoid state estimation fusing kinematic, inertial and LIDAR sensing
This paper describes an algorithm for the probabilistic fusion of sensor data from a variety of modalities (inertial, kinematic and LIDAR) to produce a single consistent position estimate for a walking humanoid. Of specific interest is our approach for continuous LIDAR-based localization which
maintains reliable drift-free alignment to a prior map using a Gaussian Particle Filter. This module can be bootstrapped by constructing the map on-the-fly and performs robustly in a variety of challenging field situations. We also discuss a two-tier estimation hierarchy which preserves registration to this map and other objects in the robotâs vicinity while also contributing to direct low-level control of a Boston Dynamics Atlas robot. Extensive experimental demonstrations illustrate how the approach can enable the humanoid to walk over uneven terrain without stopping (for tens of minutes), which would otherwise not be possible. We characterize the performance of the estimator for each sensor modality and discuss the
computational requirements.United States. Air Force Research Laboratory (Award FA8750-12-1-0321
WISP genes are members of the connective tissue growth factor family that are up-regulated in Wnt-1-transformed cells and aberrantly expressed in human colon tumors
Wnt family members are critical to many developmental processes, and components of the Wnt signaling pathway have been linked to tumorigenesis in familial and sporadic colon carcinomas. Here we report the identification of two genes, WISP-1 and WISP-2, that are up-regulated in the mouse mammary epithelial cell line C57MG transformed by Wnt-1, but not by Wnt-4. Together with a third related gene, WISP-3, these proteins define a subfamily of the connective tissue growth factor family. Two distinct systems demonstrated WISP induction to be associated with the expression of Wnt-1. These included (i) C57MG cells infected with a Wnt-1 retroviral vector or expressing Wnt-1 under the control of a tetracyline repressible promoter, and (ii) Wnt-1 transgenic mice. The WISP-1 gene was localized to human chromosome 8q24.1-8q24.3. WISP-1 genomic DNA was amplified in colon cancer cell lines and in human colon tumors and its RNA overexpressed (2- to >30-fold) in 84% of the tumors examined compared with patient-matched normal mucosa. WISP-3 mapped to chromosome 6q22-6q23 and also was overexpressed (4- to >40-fold) in 63% of the colon tumors analyzed. In contrast, WISP-2 mapped to human chromosome 20q12-20q13 and its DNA was amplified, but RNA expression was reduced (2- to >30-fold) in 79% of the tumors. These results suggest that the WISP genes may be downstream of Wnt-1 signaling and that aberrant levels of WISP expression in colon cancer may play a role in colon tumorigenesis
Signals of Bose Einstein condensation and Fermi quenching in the decay of hot nuclear systems
We report experimental signals of Bose-Einstein condensation in the decay of
hot Ca projectile-like sources produced in mid-peripheral collisions at
sub-Fermi energies. The experimental setup, constituted by the coupling of the
INDRA 4 detector array to the forward angle VAMOS magnetic spectrometer,
allowed us to reconstruct the mass, charge and excitation energy of the
decaying hot projectile-like sources. Furthermore, by means of quantum
fluctuation analysis techniques, temperatures and mean volumes per particle "as
seen by" bosons and fermions separately are correlated to the excitation energy
of the reconstructed system. The obtained results are consistent with the
production of dilute mixed (bosons/fermions) systems, where bosons experience a
smaller volume as compared to the surrounding fermionic gas. Our findings
recall similar phenomena observed in the study of boson condensates in atomic
traps.Comment: Submitted to Phys. Rev. Lett. (december 2014
Fragment properties of fragmenting heavy nuclei produced in central and semi-peripheral collisions
Fragment properties of hot fragmenting sources of similar sizes produced in
central and semi-peripheral collisions are compared in the excitation energy
range 5-10 AMeV. For semi-peripheral collisions a method for selecting compact
quasi-projectiles sources in velocity space similar to those of fused systems
(central collisions) is proposed. The two major results are related to
collective energy. The weak radial collective energy observed for
quasi-projectile sources is shown to originate from thermal pressure only. The
larger fragment multiplicity observed for fused systems and their more
symmetric fragmentation are related to the extra radial collective energy due
to expansion following a compression phase during central collisions. A first
attempt to locate where the different sources break in the phase diagram is
proposed.Comment: 23 pages submitted to NP
Bimodality: a possible experimental signature of the liquid-gas phase transition of nuclear matter
We have observed a bimodal behaviour of the distribution of the asymmetry
between the charges of the two heaviest products resulting from the decay of
the quasi-projectile released in binary Xe+Sn and Au+Au collisions from 60 to
100 MeV/u. Event sorting has been achieved through the transverse energy of
light charged particles emitted on the quasi-target side, thus avoiding
artificial correlations between the bimodality signal and the sorting variable.
Bimodality is observed for intermediate impact parameters for which the
quasi-projectile is identified. A simulation shows that the deexcitation step
rather than the geometry of the collision appears responsible for the bimodal
behaviour. The influence of mid-rapidity emission has been verified. The two
bumps of the bimodal distribution correspond to different excitation energies
and similar temperatures. It is also shown that it is possible to correlate the
bimodality signal with a change in the distribution of the heaviest fragment
charge and a peak in potential energy fluctuations. All together, this set of
data is coherent with what would be expected in a finite system if the
corresponding system in the thermodynamic limit exhibits a first order phase
transition.Comment: 30 pages, 31 figure
Changes in Natural Foxp3+Treg but Not Mucosally-Imprinted CD62LnegCD38+Foxp3+Treg in the Circulation of Celiac Disease Patients
Background:Celiac disease (CD) is an intestinal inflammation driven by gluten-reactive CD4+ T cells. Due to lack of selective markers it has not been determined whether defects in inducible regulatory T cell (Treg) differentiation are associated with CD. This is of importance as changes in numbers of induced Treg could be indicative of defects in mucosal tolerance development in CD. Recently, we have shown that, after encounter of retinoic acid during differentiation, circulating gut-imprinted T cells express CD62LnegCD38+. Using this new phenotype, we now determined whether alterations occur in the frequency of natural CD62L+Foxp3+ Treg or mucosally-imprinted CD62LnegCD38+Foxp3+ Treg in peripheral blood of CD patients. In particular, we compared pediatric CD, aiming to select for disease at onset, with adult CD.Methods:Cell surface markers, intracellular Foxp3 and Helios were determined by flow cytometry. Foxp3 expression was also detected by immunohistochemistry in duodenal tissue of CD patients.Results:In children, the percentages of peripheral blood CD4+Foxp3+ Treg were comparable between CD patients and healthy age-matched controls. Differentiation between natural and mucosally-imprinted Treg on the basis of CD62L and CD38 did not uncover differences in Foxp3. In adult patients on gluten-free diet and in refractory CD increased percentages of circulating natural CD62L+Foxp3+ Treg, but normal mucosally-imprinted CD62LnegCD38+Foxp3+ Treg frequencies were observed.Conclusions:Our data exclude that significant numeric deficiency of mucosally-imprinted or natural Foxp3+ Treg explains exuberant effector responses in CD. Changes in natural Foxp3+ Treg occur in a subset of adult patients on a gluten-free diet and in refractory CD patients
Multifragmentation threshold in ^{93}Nb+{nat}Mg collisions at 30 MeV/nucleon
We analyzed the on reaction at 30 MeV/nucleon in the aim
of disentangling binary sequential decay and multifragmentation decay close to
the energy threshold, i.e. MeV/nucleon. Using the backtracing
technique applied to the statistical models GEMINI and SMM we reconstruct
simulated charge, mass and excitation energy distributions and compare them to
the experimental ones. We show that data are better described by SMM than by
GEMINI in agreement with the fact that multifragmentation is responsible for
fragment production at excitation energies around 3 MeV/nucleon.Comment: 16 pages, 12 figures, 5 tables Soumis \`a Nuclear Physics
Multifragmentation process for different mass asymmetry in the entrance channel around the Fermi energy
The influence of the entrance channel asymmetry upon the fragmentation
process is addressed by studying heavy-ion induced reactions around the Fermi
energy. The data have been recorded with the INDRA 4pi array. An event
selection method called the Principal Component Analysis is presented and
discussed. It is applied for the selection of central events and furthermore to
multifragmentation of single source events. The selected subsets of data are
compared to the Statistical Multifragmentation Model (SMM) to check the
equilibrium hypothesis and get the source characteristics. Experimental
comparisons show the evidence of a decoupling between thermal and compresional
(radial flow) degrees of freedom in such nuclear systems.Comment: 28 pages, 15 figures, article sumitted to Nuclear Physics
Yield scaling, size hierarchy and fluctuations of observables in fragmentation of excited heavy nuclei
Multifragmentation properties measured with INDRA are studied for single
sources produced in Xe+Sn reactions in the incident energy range 32-50 A MeV
and quasiprojectiles from Au+Au collisions at 80 A MeV. A comparison for both
types of sources is presented concerning Fisher scaling, Zipf law, fragment
size and fluctuation observables. A Fisher scaling is observed for all the
data. The pseudo-critical energies extracted from the Fisher scaling are
consistent between Xe+Sn central collisions and Au quasi-projectiles. In the
latter case it also corresponds to the energy region at which fluctuations are
maximal. The critical energies deduced from the Zipf analysis are higher than
those from the Fisher analysis.Comment: 30 pages, accepted for publication in Nuclear Physics A, references
correcte
- âŠ