1,503 research outputs found
Maximal Sobolev regularity for solutions of elliptic equations in infinite dimensional Banach spaces endowed with a weighted Gaussian measure
Let be a separable Banach space endowed with a non-degenerate centered
Gaussian measure . The associated Cameron-Martin space is denoted by .
Let , where is a sufficiently regular weight and
is a convex and continuous function. In this paper
we are interested in the regularity of the weak solutions of elliptic
equations of the type where , and is the self-adjoint operator associated with the
quadratic form \[(\psi,\varphi)\mapsto
\int_X\left\langle\nabla_H\psi,\nabla_H\varphi\right\rangle_Hd\nu\qquad\psi,\varphi\in
W^{1,2}(X,\nu).\
Typing Context-Dependent Behavioural Variation
Context Oriented Programming (COP) concerns the ability of programs to adapt
to changes in their running environment. A number of programming languages
endowed with COP constructs and features have been developed. However, some
foundational issues remain unclear. This paper proposes adopting static
analysis techniques to reason on and predict how programs adapt their
behaviour. We introduce a core functional language, ContextML, equipped with
COP primitives for manipulating contexts and for programming behavioural
variations. In particular, we specify the dispatching mechanism, used to select
the program fragments to be executed in the current active context. Besides the
dynamic semantics we present an annotated type system. It guarantees that the
well-typed programs adapt to any context, i.e. the dispatching mechanism always
succeeds at run-time.Comment: In Proceedings PLACES 2012, arXiv:1302.579
Very Large PoreMesoporous Bioactive Silicate Glasses: Comparison of Behavior toward Classical Mesoporous Bioactive Glasses in Terms of Drug Loading/Release and Bioactivity
Abstract: Considering the increase in patients who suffer from osteoporosis and the bone defects
that occur in these patients, bone tissue regeneration is a promising option to solve this problem. To
achieve a synergistic effect between the synthesis of a proper structure and bioactive/pharmaceutical
activity, ions with a physiological effect can be added to silica structures, such as Ca2+, thanks to its
bioactive behavior, and Ga3+ for its antibacterial and anticancer action. In this work, the synthesis
of large pore mesoporous silica (LPMS), potential bioactive glasses containing Ca2+ and Ga3+, has
been studied. Corresponding structures, in terms of composition, have been synthesized following
the Sol-Gel EISA (Evaporation Induced Self-Assembly) process (obtaining Classical Mesoporous
Silica, MS). Pore structure characterization of LPMSs and MSs has been performed using N2 adsorption/
desorption and Hg-porosimetry, showing the presence of pores for LPMSs in the range of
20–60 and 200–600 nm. Nisin, a polycyclic antibacterial peptide, has been used for load tests. The
load and release tests performed highlight a higher loading and releasing, doubled for LPMSs if compared
to MSs. To confirm the maintenance of the structure of LPMSs and their mechanical strength
and resistance, scanning electron microscopy images were acquired before and after release tests. Ca
and Ga release in SBF has been studied through inductively coupled plasma—optical emission spectroscopy
(ICP-OES), showing a particularly high release of these ions performed with LPMSs. The
bioactive behavior of Ca-containing structures has been confirmed using FT-IR (Fourier-transform
infrared spectroscopy), SEM-EDS (Scanning Electron Microscope-Energy Dispersive Spectroscopy),
and X-ray powder diffraction (XRDP). In conclusion, LPMSs showed better loading and releasing
properties compared with classical MS and better release in terms of active ions. In addition, it has
also been demonstrated that LPMSs have bioactive behavior (a well-known characteristic of MSs)
Very large pores mesoporous silica as new candidate for delivery of big therapeutics molecules, such as pharmaceutical peptides
The synthesis of a scaffold that can accommodate big molecules with a pharmaceutical role
is important to shield them and maintain their biological activity. In this field, silica particles with
large pores (LPMS) are innovative supports. Large pores allow for the loading of bioactive molecules
inside the structure and contemporarily their stabilization and protection. These purposes cannot be
achieved using classical mesoporous silica (MS, pore size 2–5 nm), because their pores are not big
enough and pore blocking occurs. LPMSs with different porous structures are synthesized starting
from an acidic water solution of tetraethyl orthosilicate reacting with pore agents (Pluronic® F127
and mesitylene), performing hydrothermal and microwave-assisted reactions. Time and surfactant
optimization were performed. Loading tests were conducted using Nisin as a reference molecule
(polycyclic antibacterial peptide, with dimensions of 4–6 nm); UV-Vis analyses on loading solutions
were performed. For LPMSs, a significantly higher loading efficiency (LE%) was registered. Other
analyses (Elemental Analysis, Thermogravimetric Analysis and UV-Vis) confirmed the presence of
Nisin in all the structures and its stability when loaded on them. LPMSs showed a lower decrease
in specific surface area if compared to MS; in terms of the difference in LE% between samples, it is
explained considering the filling of pores for LPMSs, a phenomenon that is not allowed for MSs.
Release studies in simulated body fluid highlight, only for LPMSs, a controlled release, considering
the longer time scale of release. Scanning Electron Microscopy images acquired before and after
release tests shows the LPMSs’ maintenance of the structure, demonstrating strength and mechanical
resistance of structures. In conclusion, LPMSs were synthesized, performing time and surfactant
optimization. LPMSs showed better loading and releasing properties with respect to classical MS. All collected data confirm a pore blocking for MS and an in-pore loading for LPMS
Neutrino current in a gravitational plane wave collision background
The behaviour of a massless Dirac field on a general spacetime background
representing two colliding gravitational plane waves is discussed in the
Newman-Penrose formalism. The geometrical properties of the neutrino current
are analysed and explicit results are given for the special Ferrari-Ibanez
solution.Comment: 17 pages, 6 Postscript figures, accepted by International Journal of
Modern Physics
Test particle motion in a gravitational plane wave collision background
Test particle geodesic motion is analysed in detail for the background
spacetimes of the degenerate Ferrari-Ibanez colliding gravitational wave
solutions. Killing vectors have been used to reduce the equations of motion to
a first order system of differential equations which have been integrated
numerically. The associated constants of the motion have also been used to
match the geodesics as they cross over the boundary between the single plane
wave and interaction zones.Comment: 11 pages, 6 Postscript figure
Eliciting the Double-edged Impact of Digitalisation: a Case Study in Rural Areas
Designing systems that account for sustainability concerns demands for a
better understanding of the \textit{impact} that digital technology
interventions can have on a certain socio-technical context. However, limited
studies are available about the elicitation of impact-related information from
stakeholders, and strategies are particularly needed to elicit possible
long-term effects, including \textit{negative} ones, that go beyond the planned
system goals.
This paper reports a case study about the impact of digitalisation in remote
mountain areas, in the context of a system for ordinary land management and
hydro-geological risk control. The elicitation process was based on interviews
and workshops. In the initial phase, past and present impacts were identified.
In a second phase, future impacts were forecasted through the discussion of two
alternative scenarios: a dystopic, technology-intensive one, and a
technology-balanced one. The approach was particularly effective in identifying
negative impacts.
Among them, we highlight the higher stress due to the excess of connectivity,
the partial reduction of decision-making abilities, and the risk of
marginalisation for certain types of stakeholders. The study posits that before
the elicitation of system goals, requirements engineers need to identify the
socio-economic impacts of ICT technologies included in the system, as negative
effects need to be properly mitigated. Our study contributes to the literature
with: a set of impacts specific to the case, which can apply to similar
contexts; an effective approach for impact elicitation; and a list of lessons
learned from the experience.Comment: Accepted to IEEE RE 2023, International Conference on Requirements
Engineering, 10 pages plus 2 pages of reference
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