2,184 research outputs found
Co-axial wet-spinning in 3D Bioprinting: state of the art and future perspective of microfluidic integration
Nowadays, 3D bioprinting technologies are rapidly emerging in the field of tissue engineering and regenerative medicine as effective tools enabling the fabrication of advanced tissue constructs that can recapitulate in vitro organ/tissue functions. Selecting the best strategy for bioink deposition is often challenging and time consuming process, as bioink properties-in the first instance, rheological and gelation-strongly influence the suitable paradigms for its deposition. In this short review, we critically discuss one of the available approaches used for bioprinting-namely co-axial wet-spinning extrusion. Such a deposition system, in fact, demonstrated to be promising in terms of printing resolution, shape fidelity and versatility when compared to other methods. An overview of the performances of co-axial technology in the deposition of cellularized hydrogel fibres is discussed, highlighting its main features. Furthermore, we show how this approach allows (i) to decouple the printing accuracy from bioink rheological behaviour-thus notably simplifying the development of new bioinks- A nd (ii) to build heterogeneous multi-materials and/or multicellular constructs that can better mimic the native tissues when combined with microfluidic systems. Finally, the ongoing challenges and the future perspectives for the ultimate fabrication of functional constructs for advanced research studies are highlighted. © 2018 IOP Publishing Ltd
Position Paper: On the Role of Abductive Reasoning in Semantic Image Segmentation
This position paper provides insights aiming at resolving the most pressing needs and issues of computer vision algorithms. Specifically, these problems relate to the scarcity of data, the inability of such algorithms to adapt to never-seen-before conditions, and the challenge of developing explainable and trustworthy algorithms.
This work proposes the incorporation of reasoning systems, and in particular of abductive reasoning, into image segmentation algorithms as a potential solution to the aforementioned issues
Thermodynamic precision of a chain of motors: the difference between phase and noise correlation
Inspired by recent experiments on fluctuations of the flagellar beating in
sperms and C. reinhardtii, we investigate the precision of phase fluctuations
in a system of nearest-neighbour-coupled molecular motors. We model the system
as a Kuramoto chain of oscillators with coupling constant and noisy
driving. The precision is a Fano-factor-like observable which obeys the
Thermodynamic Uncertainty Relation (TUR), that is an upper bound related to
dissipation. We first consider independent motor noises with diffusivity :
in this case the precision goes as , coherently with the behavior of
spatial order. The minimum observed precision is that of the uncoupled
oscillator , the maximum observed one is , saturating the
TUR bound. Then we consider driving noises which are spatially correlated, as
it may happen in the presence of some direct coupling between adjacent motors.
Such a spatial correlation in the noise does not reduce evidently the degree of
spatial correlation in the chain, but sensibly reduces the maximum attainable
precision , coherently with experimental observations. The limiting
behaviors of the precision, in the two opposite cases of negligible interaction
and strong interaction, are well reproduced by the precision of the single
chain site and the precision of the center of mass of the chain
with : both do not depend on the degree of
interaction in the chain, but decreases with the correlation length
of the motor noises.Comment: 7 pages, 7 figures, accepted on the Special Issue dedcated to
STATPHYS28 on the journal J. Stat. Mec
Epistemic Logic Programs: a study of some properties
Epistemic Logic Programs (ELPs), extend Answer Set Programming (ASP) with
epistemic operators. The semantics of such programs is provided in terms of
world views, which are sets of belief sets, i.e., syntactically, sets of sets
of atoms. Different semantic approaches propose different characterizations of
world views. Recent work has introduced semantic properties that should be met
by any semantics for ELPs, like the Epistemic Splitting Property, that, if
satisfied, allows to modularly compute world views in a bottom-up fashion,
analogously to ``traditional'' ASP. We analyze the possibility of changing the
perspective, shifting from a bottom-up to a top-down approach to splitting. We
propose a basic top-down approach, which we prove to be equivalent to the
bottom-up one. We then propose an extended approach, where our new definition:
(i) is provably applicable to many of the existing semantics; (ii) operates
similarly to ``traditional'' ASP; (iii) provably coincides under any semantics
with the bottom-up notion of splitting at least on the class of Epistemically
Stratified Programs (which are, intuitively, those where the use of epistemic
operators is stratified); (iv) better adheres to common ASP programming
methodology.Comment: Under consideration in Theory and Practice of Logic Programming
(TPLP
Multi-context systems in time
In this paper we consider how to enhance flexibility and generality in Multi-Context Systems (MCS) by considering that contexts can evolve over time, that bridge-rule application can be proactive (according to a context's specific choice), and not instantaneous but requiring an execution mechanism. We introduce bridge-rule patterns to make bridge-rules parametric w.r.t. the involved contexts
The effect of X-ray dust-scattering on a bright burst from the magnetar 1E 1547.0-5408
A bright burst, followed by an X-ray tail lasting ~10 ks, was detected during
an XMM-Newton observation of the magnetar 1E 1547.0-5408 carried out on 2009
February 3. The burst, also observed by SWIFT/BAT, had a spectrum well fit by
the sum of two blackbodies with temperatures of ~4 keV and 10 keV and a fluence
in the 0.3-150 keV energy range of ~1e-5 erg/cm2. The X-ray tail had a fluence
of ~4e-8 erg/cm2. Thanks to the knowledge of the distances and relative optical
depths of three dust clouds between us and 1E 1547.0-5408, we show that most of
the X-rays in the tail can be explained by dust scattering of the burst
emission, except for the first ~20-30 s. We point out that other X-ray tails
observed after strong magnetar bursts may contain a non-negligible contribution
due to dust scattering.Comment: 8 pages, 2 tables and 10 figures; accepted to publication in MNRA
Features of the Primordial Universe in f(R)-gravity as viewed in the Jordan frame
We analyze some relevant features of the primordial Universe as viewed in the
Jordan frame formulation of the f(R)-gravity, especially when the potential
term of the non-minimally coupled scalar field is negligible. We start
formulating the Hamiltonian picture in the Jordan frame, using the 3-metric
determinant as a basic variable and we outline that its conjugated momentum
appears linearly only in the scalar constraint. Then, we construct the basic
formalism to characterize the dynamics of a generic inhomogeneous cosmological
model and specialize it in order to describe behaviors of the Bianchi
Universes, both on a classical and a quantum regime. As a fundamental issue, we
demonstrate that, when the potential term of the additional scalar mode is
negligible near enough to the initial singularity, the Bianchi IX cosmology is
no longer affected by the chaotic behavior, typical in vacuum of the standard
Einsteinian dynamics. In fact, the presence of stable Kasner stability region
and its actractive character are properly characterized. Finally, we
investigate the canonical quantization of the Bianchi I model, using as time
variable the non-minimally coupled scalar field and showing that the existence
of a conserved current is outlined for the corresponding Wheeler-DeWitt
equation. The behavior of a localized wave-packet for the isotropic Universe is
also evolved, demonstrating that the singularity is still present in this
revised quantum dynamics.Comment: 20 pages, 8 figure
Psychosocial Interventions for the Enhancement of Psychological Resources among Dyslexic Adults: A Systematic Review
Dyslexic employees are likely to be more at risk of low levels of personal resources because of their cognitive makeup compared to their non-dyslexic counterparts. Low personal resources, in turn, may lead to low employability because of difficulties in positively facing transitions. This research aimed to systematically review evidence on interventions for improving psychological resources in dyslexic adults. We searched Scopus, ERIC EBSCOhost, PsycINFO, Social Science Citation Index Web of Science, and Universe up to May 2020. We also examined the reference lists of published studies. We included studies that compared any intervention format against no intervention, any other intervention considered as a comparator by the authors, or that had no control group. Participants were dyslexic adults aged minimum 18 years old. We included four studies with 278 participants. Studies were run in the UK, Sweden, and Finland. Two studies involved a control group, and two studies were observational. Interventions varied between studies in intensity, duration, and format (individual and small groups). Risk of bias was unclear for most risk criteria. Findings from this review show that there is initial evidence suggesting initiatives can be effective in supporting a set of personal resources, i.e., self-confidence, organization, time, and stress-management, which are important in allowing dyslexic adults\u2019 positive adjustment in the workplace. Yet, more studies are needed to improve outcome assessment and study design
RELATIVISMO MORAL NAS CIÊNCIAS SOCIAIS COMPREENDIDO A PARTIR DAS IDEIAS E PERSPECTIVAS DE KUHN A ARENDT
The present essay has the purpose of explaining, though the perspectives of six different thinkers and scientists, what is the philosophical idea of Moral Relativism within Social Sciences – with a special focus on International Relations –, how might it be useful in understanding its (philosophical) implications for future research, and what could be the possible alternatives. The thinkers and authors discussed are Thomas Kuhn, Hannah Arendt, Charles Wright Mills, Arnold Brecht, Kees Van Der Pijl and Jeppe Nicolaisen. Some of them don’t discuss directly about Moral Relativism, while others deal specifically with the theme. Ideas of what power and truth are also discussed. By the end of the essay it is affirmed how this philosophical idea was and is used by the elite to influence unconsciously the opinion and moral ideas for their own benefits, and to keep the status-quo.O presente ensaio tem por objetivo explicar, através das perspectivas de seis diferentes pensadores e cientistas, o que é a ideia filosófica de Relativismo Moral nas Ciências Sociais - com especial enfoque nas Relações Internacionais -, como pode ser útil a sua compreensão (filosófica), quais as implicações para pesquisas futuras, e quais poderiam ser as alternativas possÃveis. Os pensadores e autores discutidos são Thomas Kuhn, Hannah Arendt, Charles Wright Mills, Arnold Brecht, Kees Van Der Pijl e Jeppe Nicolaisen. Alguns deles não discutem diretamente sobre o Relativismo Moral, enquanto outros tratam especificamente do tema. Idéias sobre o que é poder e verdade também são discutidas. Ao final do ensaio afirma-se como essa ideia filosófica foi e ainda é utilizada pelas elites para influenciar inconscientemente a opinião e as ideias morais em seu próprio benefÃcio, ou seja para manter o status-quo
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