995 research outputs found
Circular product design. A multiple loops life cycle design approach for the circular economy
The circular economy is a high priority subject of discussion in the current political and academic contexts; however, practical approaches in relevant disciplines like design are in need of development. This article proposes a conceptual framework for circular product design, based on four multiple loops strategies: (I) design to slow the loops, (II) design to close the loops, (III) design for bio-inspired loops, and (IV) design for bio-based loops. Recent literature, notably on life cycle design strategies, the circular economy conceptual model and the European Commission’s Circular Economy Package, is reviewed and product design cases illustrating each of the proposed are analysed. The article argues that different ‘circular’ approaches centred upon the life cycle design phases can provide practical guiding strategies during the design process and thus promote sustainable design solutions for the circular economy within the United Nation’s sustainable development goals
Wound Healing. Therapeutics
As feridas crónicas representam um problema grave de saúde pública e uma das causas de grande consumo de recursos em saúde. Recentes avanços no conhecimento do mecanismo de cicatrização levaram ao desenvolvimento de novos tratamentos. Definir o papel e eficácia destes novos tratamentos é o próximo passo.
Os autores procuraram neste trabalho abordar algumas terapêuticas, que não terapia compressiva e material de penso, na cicatrização de feridas crónicas
Popular matchings with two-sided preferences and one-sided ties
We are given a bipartite graph where each vertex has a
preference list ranking its neighbors: in particular, every ranks its
neighbors in a strict order of preference, whereas the preference lists of may contain ties. A matching is popular if there is no matching
such that the number of vertices that prefer to exceeds the number of
vertices that prefer to~. We show that the problem of deciding whether
admits a popular matching or not is NP-hard. This is the case even when
every either has a strict preference list or puts all its neighbors
into a single tie. In contrast, we show that the problem becomes polynomially
solvable in the case when each puts all its neighbors into a single
tie. That is, all neighbors of are tied in 's list and desires to be
matched to any of them. Our main result is an algorithm (where ) for the popular matching problem in this model. Note that this model
is quite different from the model where vertices in have no preferences and
do not care whether they are matched or not.Comment: A shortened version of this paper has appeared at ICALP 201
Exploiting graphlet decomposition to explain the structure of complex networks: the GHuST framework
The characterization of topology is crucial in understanding network evolution and behavior. This paper presents an innovative approach, the GHuST framework to describe complex-network topology from graphlet decomposition. This new framework exploits the local information provided by graphlets to give a global explanation of network topology. The GHuST framework is comprised of 12 metrics that analyze how 2- and 3-node graphlets shape the structure of networks. The main strengths of the GHuST framework are enhanced topological description, size independence, and computational simplicity. It allows for straight comparison among different networks disregarding their size. It also reduces the complexity of graphlet counting, since it does not use 4- and 5-node graphlets. The application of the novel framework to a large set of networks shows that it can classify networks of distinct nature based on their topological properties. To ease network classification and enhance the graphical representation of them, we reduce the 12 dimensions to their main principal components. Furthermore, the 12 dimensions are easily interpretable. This enables the connection between complex-network analyses and diverse real applications
L-functions with large analytic rank and abelian varieties with large algebraic rank over function fields
The goal of this paper is to explain how a simple but apparently new fact of
linear algebra together with the cohomological interpretation of L-functions
allows one to produce many examples of L-functions over function fields
vanishing to high order at the center point of their functional equation. The
main application is that for every prime p and every integer g>0 there are
absolutely simple abelian varieties of dimension g over Fp(t) for which the BSD
conjecture holds and which have arbitrarily large rank.Comment: To appear in Inventiones Mathematica
Beyond deficit-based models of learners' cognition: Interpreting engineering students' difficulties with sense-making in terms of fine-grained epistemological and conceptual dynamics
Researchers have argued against deficit-based explanations of students'
troubles with mathematical sense-making, pointing instead to factors such as
epistemology: students' beliefs about knowledge and learning can hinder them
from activating and integrating productive knowledge they have. In this case
study of an engineering major solving problems (about content from his
introductory physics course) during a clinical interview, we show that "Jim"
has all the mathematical and conceptual knowledge he would need to solve a
hydrostatic pressure problem that we posed to him. But he reaches and sticks
with an incorrect answer that violates common sense. We argue that his lack of
mathematical sense-making-specifically, translating and reconciling between
mathematical and everyday/common-sense reasoning-stems in part from his
epistemological views, i.e., his views about the nature of knowledge and
learning. He regards mathematical equations as much more trustworthy than
everyday reasoning, and he does not view mathematical equations as expressing
meaning that tractably connects to common sense. For these reasons, he does not
view reconciling between common sense and mathematical formalism as either
necessary or plausible to accomplish. We, however, avoid a potential "deficit
trap"-substituting an epistemological deficit for a concepts/skills deficit-by
incorporating multiple, context-dependent epistemological stances into Jim's
cognitive dynamics. We argue that Jim's epistemological stance contains
productive seeds that instructors could build upon to support Jim's
mathematical sense-making: He does see common-sense as connected to formalism
(though not always tractably so) and in some circumstances this connection is
both salient and valued.Comment: Submitted to the Journal of Engineering Educatio
Metal-ion zeolites obtained by chemical and mechanochemical methods as Fenton-like catalysts for health applications
One of the critical steps for the development and health applications of inorganic nanoparticles is to exhibit high efficiency without inducing toxicity. In this work, metal-ion zeolites were developed to be used as Fenton-like catalysts for health applications. ZSM-5 and BEA zeolites were modified through chemical and mechanochemical methods to obtain nanomaterials with tuned particle size and texture. Characterization data showed that the modified materials kept the crystal structure although some textural modifications occurred. Upon Mn2+loading, the catalytic behavior was evaluated by Fenton-like reaction using physiological and mild acidic conditions (37 ºC, pH=7.4 and 6.4 and 50 M H2O2), since these conditions are relevant to various pathological environments. MnBEA series showed the best results by Fenton-like reactions, revealing the great potential of metal-zeolite nanomaterials for health applications.V.I. and A.R.B. thank for the PhD grants, UI/BD/152219/2021 and SFRH/BD/141058/2018, respectively. ASM thanks FCT for the Assistant Researcher contract CEECIND/01371/2017 (Embrace Project). This work was supported by FCT (Foundation for Science and Technology, Portugal) by the projects: UIDB/00100/2020. UIDP/00100/2020 and LA/P/0056/2020, CQ/UM (UID/QUI/0686/2020), CEB (UIDB/04469/2020) and LABBELS (LA/P/0029/2020), and Instituto Politécnico de Lisboa (IPL) through Project IPL/2022/ZeoMed ISEL.info:eu-repo/semantics/publishedVersio
Pancreatic panniculitis: a cutaneous manifestation of acute pancreatitis
Pancreatic panniculitis is a rare disease in which necrosis of fat in the panniculus and other distant foci occurs in the setting of pancreatic diseases; these diseases include acute and chronic pancreatitis, pancreatic carcinoma, pseudocyst, and other pancreatic diseases. This malady is manifested as tender erythematous nodules on the legs, buttock, or trunk. Histopathologically, it shows the pathognomonic findings of focal subcutaneous fat necrosis and ghost-like anucleated cells with a thick shadowy wall. We herein report a case of fatal pancreatic panniculitis that was associated with acute pancreatitis in a 50-yr-old man. He presented with a 3-week history of multiple tender skin nodules, abdominal pain and distension. Laboratory and radiologic findings revealed acute pancreatitis, and skin biopsy showed pancreatic panniculitis. Despite intensive medical care, he died of multi-organ failure 3 weeks after presentation
Leprosy and rheumatoid arthritis: consequence or association?
Leprosy or Hansen's disease is a chronic granulomatous infectious disease caused by Mycobacterium leprae with a high prevalence in some developing countries however, it is rarely seen in non-endemic regions. Arthritis has been described in all types of Hansen's disease. Chronic arthritis is known to exist even in paucibacillary forms, resolved or treated disease and in patients without reaction, suggesting a perpetuated inflammatory process. In these cases leprosy can mimic some autoimmune diseases such as rheumatoid arthritis. When a patient with a history of leprosy presents with a symmetric, distal, polyarthritis the diagnosis may not be linear. Possibly it is a rheumatoid-like leprous arthritis with M leprae acting as the trigger element for the chronic process or it is an overlap condition, with a concomitant rheumatoid arthritis? A case report of a patient with a chronic inflammatory arthritis with 10 years of evolution is presented. The differential diagnosis between leprous and rheumatoid arthritis is discussed
O(1/N_f) Corrections to the Thirring Model in 2<d<4
The Thirring model, that is, a relativistic field theory of fermions with a
contact interaction between vector currents, is studied for dimensionalities
2<d<4 using the 1/N_f expansion, where N_f is the number of fermion species.
The model is found to have no ultraviolet divergences at leading order provided
a regularization respecting current conservation is used. Explicit O(1/N_f)
corrections are computed, and the model shown to be renormalizable at this
order in the massless limit; renormalizability appears to hold to all orders
due to a special case of Weinberg's theorem. This implies there is a universal
amplitude for four particle scattering in the asymptotic regime. Comparisons
are made with both the Gross-Neveu model and QED.Comment: 22 pages in plain TeX, with 7 figs included using psfig.tex (Minor
conceptual changes - algebra unaffected
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