2,625 research outputs found
FM-track: a fiducial marker tracking software for studying cell mechanics in a three-dimensional environment
Tracking the deformation of fiducial markers in the vicinity of living cells embedded in compliant synthetic or biological gels is a powerful means to study cell mechanics and mechanobiology in three-dimensional environments. However, current approaches to track and quantify three-dimensional (3D) fiducial marker displacements remain ad-hoc, can be difficult to implement, and may not produce reliable results. Herein, we present a compact software package entitled “FM-Track,” written in the popular Python language, to facilitate feature-based particle tracking tailored for 3D cell micromechanical environment studies. FM-Track contains functions for pre-processing images, running fiducial marker tracking, and post-processing and visualization. FM-Track can thus aid the study of cellular mechanics and mechanobiology by providing an extensible software platform to more reliably extract complex local 3D cell contractile information in transparent compliant gel systems.https://www.sciencedirect.com/science/article/pii/S2352711019303474Published versio
Automated Determination of Stellar Parameters from Simulated Dispersed Images for DIVA
We have assessed how well stellar parameters (T_eff, logg and [Fe/H]) can be
retrieved from low-resolution dispersed images to be obtained by the DIVA
satellite. Although DIVA is primarily an all-sky astrometric mission, it will
also obtain spectrophotometric information for about 13 million stars
(operational limiting magnitude V ~ 13.5 mag). Constructional studies foresee a
grating system yielding a dispersion of ~200nm/mm on the focal plane (first
spectral order). For astrometric reasons there will be no cross dispersion
which results in the overlapping of the first to third diffraction orders. The
one-dimensional, position related intensity function is called a DISPI
(DISPersed Intensity). We simulated DISPIS from synthetic spectra (...) for a
limited range of metallicites i.e. our results are for [Fe/H] in the range -0.3
to 1 dex. We show that there is no need to deconvolve these low resolution
signals in order to obtain basic stellar parameters. Using neural network
methods and by including simulated data of DIVA's UV telescope, we can
determine T_eff to an average accuracy of about 2% for DISPIS from stars with
2000 K < T_eff < 20000 K and visual magnitudes of V=13 mag (end of mission
data). logg can be determined for all temperatures with an accuracy better than
0.25 dex for magnitudes brighter than V=12 mag. For low temperature stars with
2000 K < T_eff < 5000 K and for metallicities in the range -0.3 to +1 dex a
determination of [Fe/H] is possible (to better than 0.2 dex) for these
magnitudes. Additionally we examined the effects of extinction E(B-V) on DISPIS
and found that it can be determined to better than 0.07 mag for magnitudes
brighter than V=14 mag if the UV information is included.Comment: 12 pages, 8 figures, Accepted for publication in A&
Self-consistent calculations of the electric giant dipole resonances in light and heavy mass nuclei
While bulk properties of stable nuclei are successfully reproduced by
mean-field theories employing effective interactions, the dependence of the
centroid energy of the electric giant dipole resonance on the nucleon number A
is not. This problem is cured by considering many-particle correlations beyond
mean-field theory, which we do within the "Quasiparticle Time Blocking
Approximation". The electric giant dipole resonances in O, Ca,
and Pb are calculated using two new Skyrme interactions.Comment: 4 pages, 4 figure
The Łojasiewicz exponent over a field of arbitrary characteristic
Let K be an algebraically closed field and let K((XQ)) denote the field
of generalized series with coefficients in K. We propose definitions of the local
Łojasiewicz exponent of F = ( f1, . . . , fm) ∈ K[[X, Y ]]m as well as of the
Łojasiewicz exponent at infinity of F = ( f1, . . . , fm) ∈ K[X, Y ]m, which generalize
the familiar case of K = C and F ∈ C{X, Y }m (resp. F ∈ C[X, Y ]m), see
Cha˛dzy´nski and Krasi´nski (In: Singularities, 1988; In: Singularities, 1988; Ann Polon
Math 67(3):297–301, 1997; Ann Polon Math 67(2):191–197, 1997), and prove some
basic properties of such numbers. Namely, we show that in both cases the exponent
is attained on a parametrization of a component of F (Theorems 6 and 7), thus being
a rational number. To this end, we define the notion of the Łojasiewicz pseudoexponent
of F ∈ (K((XQ))[Y ])m for which we give a description of all the generalized
series that extract the pseudoexponent, in terms of their jets. In particular, we show
that there exist only finitely many jets of generalized series giving the pseudoexponent
of F (Theorem 5). The main tool in the proofs is the algebraic version of Newton’s
Polygon Method. The results are illustrated with some explicit examples
S50-01 Depression and bipolar disorder: Is prevention of mania possible? Critical issues on diagnostic criteria
Diagnostic criteria for bipolar disorder in DSM IV require the occurrence of a manic or hypomanic episode. The scant appropriateness of these criteria compared with Kraepelin"s concept of manic depressive insanity has been repeatedly reported and the concept of bipolar spectrum has been proposed for more than 30 years. The negative consequences of pure adherence to operational diagnostic criteria on clinical needs are presented in terms of community epidemiology results and in terms of clinical evidences and the inadequate treatment of depressive and anxiety episodes and the risk of manic switch with antidepressant drugs are discussed.The epidemiological survey conducted in Sesto Fiorentino showed that depressive episodes in patients with subthreshold mania or hypomania were different from the clinical presentation of pure unipolar depressives episodes confirming not only the numeric impact but also qualitative differences between these groups of patients.Our clinical study where predictors of mania have been prospectively evaluated in a trans nosographic sample of outpatients demonstrated that aspects related to bipolarity predicted manic shift regardless of the diagnosis. DSM IV criteria seem not to be able to detect and describe a group of patients relevant both on epidemiological and on clinical level. These findings underline the need of a careful examination of patients treatment and validate the rule of further research in definition of mood disorders boundaries for prevention strategies
Étude des techniques de recommandation et de contextualisation pour la conception d'une application touristique mobile
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