5,803 research outputs found
Recommended from our members
Protein fluorescence of nicotinamide nucleotide-dependent dehydrogenases
Electrophysiological Assessment of Primary Cortical Neurons Genetically Engineered using Iron Oxide Nanoparticles
The development of safe technologies to genetically modify neurons is of great interest in regenerative neurology, for both translational and basic science applications. Such approaches have conventionally been heavily reliant on viral transduction methods, which have safety and production limitations. Magnetofection (magnet-assisted gene transfer using iron oxide nanoparticles as vectors) has emerged as a highly promising non-viral alternative for safe and reproducible genetic modification of neurons. Despite the high potential of this technology, there is an important gap in our knowledge of the safety of this approach, namely, whether it alters neuronal function in adverse ways, such as by altering neuronal excitability and signaling. We have investigated the effects of magnetofection in primary cortical neurons by examining neuronal excitability using the whole cell patch clamp technique. We found no evidence that magnetofection alters the voltage-dependent sodium and potassium ionic currents that underpin excitability. Our study provides important new data supporting magnetofection as a safe technology for bioengineering of neuronal cell populations
Tightness for a stochastic Allen--Cahn equation
We study an Allen-Cahn equation perturbed by a multiplicative stochastic
noise which is white in time and correlated in space. Formally this equation
approximates a stochastically forced mean curvature flow. We derive uniform
energy bounds and prove tightness of of solutions in the sharp interface limit,
and show convergence to phase-indicator functions.Comment: 27 pages, final Version to appear in "Stochastic Partial Differential
Equations: Analysis and Computations". In Version 4, Proposition 6.3 is new.
It replaces and simplifies the old propositions 6.4-6.
On the dynamics of WKB wave functions whose phase are weak KAM solutions of H-J equation
In the framework of toroidal Pseudodifferential operators on the flat torus
we begin by proving the closure under
composition for the class of Weyl operators with
simbols . Subsequently, we
consider when where and we exhibit the toroidal version of the
equation for the Wigner transform of the solution of the Schr\"odinger
equation. Moreover, we prove the convergence (in a weak sense) of the Wigner
transform of the solution of the Schr\"odinger equation to the solution of the
Liouville equation on written in the measure sense.
These results are applied to the study of some WKB type wave functions in the
Sobolev space with phase functions in the class
of Lipschitz continuous weak KAM solutions (of positive and negative type) of
the Hamilton-Jacobi equation for with , and to the study of the
backward and forward time propagation of the related Wigner measures supported
on the graph of
MAGELLAN/M2FS SPECTROSCOPY of the RETICULUM 2 DWARF SPHEROIDAL GALAXY
© 2015. The American Astronomical Society. All rights reserved.We present results from spectroscopic observations with the Michigan/Magellan Fiber System (M2FS) of 182 stellar targets along the line of sight (LOS) to the newly discovered "ultrafaint" object Reticulum 2 (Ret 2). For 37 of these targets, the spectra are sufficient to provide simultaneous estimates of LOS velocity (νlos, median random error δνlos= 1.4 km s-1), effective temperature (Teff, Δ Teff K), surface gravity (loh g, δlog g = 0.63 dex), and iron abundance ([Fe/H], δ[Fe/H] = 0.47 dex). We use these results to confirm 17 stars as members of Ret 2. From the member sample we estimate a velocity dispersion of σνlos = 3.60.7+1.0km s-1 about a mean of 〈νlos〉 = 64.3-1.2+1.2 km s-1 in the solar rest frame ( ∼ -90.9 km s-1 in the Galactic rest frame), and a metallicity dispersion of σ [Fe/H] = 0.49-0.140.19 dex about a mean of 〈 [Fe/H]〉= -2.58-0.33+0.34. These estimates marginalize over possible velocity and metallicity gradients, which are consistent with zero. Our results place Ret 2 on chemodynamical scaling relations followed by the Milky Way's dwarf-galactic satellites. Under assumptions of dynamic equilibrium and negligible contamination from binary stars - both of which must be checked with deeper imaging and repeat spectroscopic observations - the estimated velocity dispersion suggests a dynamical mass of M(Rh)≈5Rhσνlos;2/(2G) = 2.4-0.8+1.4 × 105 M⊙enclosed within projected halflight radius Rh ∼32 pc, with mass-to-light ratio ≈2M (Rh)/LV = 467-168+286in solar units
MAGELLAN/M2FS SPECTROSCOPY of the RETICULUM 2 DWARF SPHEROIDAL GALAXY
We present results from spectroscopic observations with the Michigan/Magellan
Fiber System (M2FS) of 182 stellar targets along the line of sight to the
newly-discovered `ultrafaint' object Reticulum 2 (Ret 2). For 38 of these
targets, the spectra are sufficient to provide simultaneous estimates of
line-of-sight velocity (, median random error km s), effective temperature (, K), surface gravity (, dex) and
iron abundance ([Fe/H], dex). We use these
results to confirm 18 stars as members of Ret 2. From the member sample we
estimate a velocity dispersion of km
s about a mean of km
s in the solar rest frame ( km s in the Galactic rest
frame), and a metallicity dispersion of dex about a mean of . These estimates marginalize over possible
velocity and metallicity gradients, which are consistent with zero. Our results
place Ret 2 on chemodynamical scaling relations followed by the Milky Way's
dwarf-galactic satellites. Under assumptions of dynamic equilibrium and
negligible contamination from binary stars---both of which must be checked with
deeper imaging and repeat spectroscopic observations---the estimated velocity
dispersion suggests a dynamical mass of
enclosed within projected halflight radius pc, with
mass-to-light ratio in
solar units
Controls on the spatial distribution of natural pipe outlets in heavily degraded blanket peat
Natural soil pipes are recognised as a common geomorphological feature in many peatlands, and they can discharge large quantities of water and sediment. However, little is known about their morphological characteristics in heavily degraded peat systems. This paper presents a survey of pipe outlets in which the frequency and extent of natural soil pipes are measured across a heavily gullied blanket peat catchment in the Peak District of northern England. Over a stream length of 7.71 km we determined the occurrence and size of 346 pipe outlets, and found a mean frequency of 22.8 km−1 gully bank. Topographic position was an important control on the size and depth of pipe outlets. Aspect had a large influence on pipe outlet frequency, with southwest and west- facing gully banks hosting more than 43% of identified pipe outlets. Pipe outlets on streambanks with signs of headward retreat were significantly larger and closer to the peat surface compared to pipe outlets that issued onto uniform streambank edges. We suggest that larger pipe frequencies are observed on gully banks that are more susceptible to desiccation cracking, and propose that future peatland restoration works could prioritise mitigating against pipe formation by revegetating and reprofiling south and west facing gully banks
Things change: Women’s and men’s marital disruption dynamics in Italy during a time of social transformations, 1970-2003
We study women’s and men’s marital disruption in Italy between 1970 and 2003. By applying an event-history analysis to the 2003 Italian variant of the Generations and Gender Survey we found that the spread of marital disruption started among middle-highly educated women. Then in recent years it appears that less educated women have also been able to dissolve their unhappy unions. Overall we can see the beginning of a reversed educational gradient from positive to negative. In contrast the trend in men’s marital disruption risk appears as a change over time common to all educational groups, although with persisting educational differentials.determinants, educational differences, event history analysis, gender difference, Italy, marital disruption
Existence, uniqueness and structure of second order absolute minimisers
Let ⊆ Rn be a bounded open C1,1 set. In this paper we prove the existence
of a unique second order absolute minimiser u∞ of the functional
E∞(u, O) := F(·, u)L∞(O), O ⊆ measurable,
with prescribed boundary conditions for u and Du on ∂ and under natural assumptions
on F. We also show that u∞ is partially smooth and there exists a harmonic
function f∞ ∈ L1() such that
F(x, u∞(x)) = e∞ sgn
f∞(x)
for all x ∈ { f∞ = 0}, where e∞ is the infimum of the global energy
Energy solutions to one-dimensional singular parabolic problems with data are viscosity solutions
We study one-dimensional very singular parabolic equations with periodic
boundary conditions and initial data in , which is the energy space. We
show existence of solutions in this energy space and then we prove that they
are viscosity solutions in the sense of Giga-Giga.Comment: 15 page
- …