298 research outputs found
Mathematics self-confidence and the "prepayment effect" in riskless choices
We extend the analysis of a riskless choice experiment reported recently by Hochman et al. (2014). Participants select from among sets of standard playing cards valued by a simple formula. In some sessions, participants are given a prepayment associated with some of the cards, which need not be the earnings-maximizing ones. Hochman et al. find that participants choose an earnings-maximizing card less frequently when another card is prepaid. We replicate this result under the original instructions, but not with instructions which explain the payment process more explicitly. Participants who state they do not consider themselves good at mathematics make earnings-maximizing choices much less frequently overall, but those who express self-confidence in mathematics drive the treatment effect. The results suggest that even when comparisons among choices require only simple quantitative reasoning steps, market designers and regulators may need to pay close attention to how the terms of offers are expressed, explained, and implemented
Large fluctuations of the nonlinearities in isotropic turbulence. Anisotropic filtering analysis
Using a Navier–Stokes isotropic turbulent field numerically simulated in a box with a discretization of
10243 (Biferale et al., 2005), we show that the probability of having a stretching–tilting larger than a
few times the local enstrophy is low. By using an anisotropic kind of filter in the Fourier space, where
wavenumbers that have at least one component below a threshold or inside a range are removed, we
analyze these survival statistics when the large, the small inertial or the small inertial and dissipation
scales are filtered out. By considering a flow obtained by randomizing the phases of the Fourier modes,
and applying our filtering techniques, we identified clearly the properties attributable to turbulence.
It can be observed that, in the unfiltered isotropic Navier–Stokes field, the probability of the ratio
(|ω·∇U|/|ω|2) being higher than a given threshold is higher than in the fields where the large scales were
filtered out. At the same time, it is lower than in the fields where the small inertial and dissipation range
of scales is filtered out. This is basically due to the suppression of compact structures in the ranges that
have been filtered in different ways. The partial removal of the background of filaments and sheets does
not have a first order effect on these statistics. These results are discussed in the light of a hypothesized
relation between vortical filaments, sheets and blobs in physical space and in Fourier space. The study
in fact can be viewed as a kind of test for this idea and tries to highlight its limits. We conclude that a
qualitative relation in physical space and in Fourier space can be supposed to exist for blobs only. That is
for the near isotropic structures which are sufficiently described by a single spatial scale and do not suffer
from the disambiguation problem as filaments and sheets do.
Information is also given on the filtering effect on statistics concerning the inclination of the strain rate
tensor eigenvectors with respect to vorticity. In all filtered ranges, eigenvector 2 reduces its alignment,
while eigenvector 3 reduces its misalignment. All filters increase the gap between the most extensional
eigenvalue ⟨λ1⟩ and the intermediate one ⟨λ2⟩ and the gap between this last ⟨λ2⟩ and the contractile
eigenvalue ⟨λ3⟩. When the large scales are missing, the modulus of the eigenvalue 1 becomes nearly
equal to that of the eigenvalue 3, similarly to the modulus of the associated components of the enstrophy
production
Romanesque and territory. The construction materials of Sardinian medieval churches: new approaches to the valorization, conservation and restoration
This paper is intended to illustrate a multidisciplinary research project devoted to the study of the constructive materials of the Romanesque churches in Sardinia during the “Giudicati” period (11th -13th centuries). The project focuses on the relationship between a selection of monuments and their territory, both from a historical-architectural perspective and from a more modern perspective addressing future restoration works. The methodologies of the traditional art-historical research (study of bibliographic, epigraphic and archival sources, formal reading of artifacts) are flanked by new technologies: digital surveys executed with a 3D laser-scanner, analyses of the materials (stones, mortars, bricks) with different instrumental methods: X-ray fluorescence (XRF) and inductively coupled mass spectrometry (ICP-MS) for chemical composition, X-ray diffractometer (XRD) to determine the alteration phases (e.g., soluble salts), optical microscopy and electronic (SEM) to study textures, mineral assemblages and microstructures, termogravimetric/differential scanning, calorimetric analysis (TG/DTA) for the composition of the binder mortars.
This multidisciplinary approach allows the achieving of important results in an archaeometric context: 1) from a historical point of view, with the possible identification of ancient traffics, trade routes, sources of raw materials, construction phases, wall textures; 2) from a conservative point of view, by studying chemical and physical weathering processes of stone materials compatible for replacement in case of future restoration works.
Sardinian Romanesque architectural heritage is particularly remarkable: about 200 churches of different types and sizes, with the almost exclusive use of cut stones. Bi- or poly-chromy, deriving from the use of different building materials, characterizes many of these monuments, becoming also a vehicle for political and cultural meanings. The paper will present some case studies aimed to illustrate the progress of the project and the results achieved
Boschi vetusti e riserve forestali nel Veneto: patrimoni di biodiversita\u300
Vengono sintetizzate le criticita\u300 emergenti legate alle dinamiche di cambiamento della biodiversita\u300 nelle foreste del Veneto anche esaminando i dati delle politiche forestali degli ultimi decenni e delle trasformazioni di boschi e foreste di montagna, collina e pianura conseguenti all\u2019abbandono colturale e ad iniziative locali di contrasto alle alterazioni del paesaggio forestale, di miglioramento ambientale ed estetico e di difesa della biodiversita\u300 forestale e naturalistica dei territori del Veneto.
Seppur in un confronto europeo l'Italia e\u300 forse uno degli stati piu\u300 virtuosi nella gestione del patrimonio boschivo, sia in termini di risparmio di biomassa (35% di prelievo sull'incremento contro la media europea di oltre 60%) che per modalita\u300 di prelievo (e\u300 uno dei pochi stati dove il taglio a raso e\u300 vietato e, a differenza di molti paesi europei, non ammette l'imboschimento con specie esotiche), in questo approfondimento vengono esaminati gli scenari possibili di riferimento per una programmazione piu\u300 mirata, incisiva ed innovativa delle politiche di tutela della biodiversita\u300 forestale del Veneto, guardando ad alcune esperienze europee volte alla tutela e valorizzazione dei boschi antichi o vetusti.
Boschi e foreste si stanno espandendo nel Veneto anche in pianura: ma questo trend e\u300 frutto dell\u2019abbandono colturale e/o conseguenza di una programmazione territoriale adeguata? Si propongono linee guida per iniziative locali di contrasto alla banalizzazione estetica ed ambientale del paesaggio e per contro di miglioramento della difesa della biodiversita\u300 forestale e naturalistica dei territori del Veneto partendo dalla tutela del patrimonio genetico dei \u201cboschi vetusti\u201d
PCSK9 Expression in Epicardial Adipose Tissue : Molecular Association with Local Tissue Inflammation
Epicardial adipose tissue (EAT) has the unique property to release mediators that nourish the heart in healthy conditions, an effect that becomes detrimental when volume expands and proinflammatory cytokines start to be produced. Proprotein convertase subtilisin/kexin type 9 (PCSK9), a proinflammatory mediator involved in atherosclerosis, is also produced by visceral fat. Due to the correlation of inflammation with PCSK9 and EAT enlargement, we evaluated whether PCSK9 was expressed in EAT and associated with EAT inflammation and volume. EAT samples were isolated during surgery. EAT thickness was measured by echocardiography. A microarray was used to explore EAT transcriptoma. The PCSK9 protein levels were measured by Western Blot in EAT and ELISA in plasma. PCSK9 was expressed at both the gene and protein levels in EAT. We found a positive association with EAT thickness and local proinflammatory mediators, in particular, chemokines for monocytes and lymphocytes. No association was found with the circulating PCSK9 level. The expression of PCSK9 in EAT argues that PCSK9 is part of the EAT secretome and EAT inflammation is associated with local PCSK9 expression, regardless of circulating PCSK9 levels. Whether reducing EAT inflammation or PCSK9 local levels may have beneficial effects on EAT metabolism and cardiovascular risk needs further investigations
Heterogeneity in Preferences towards Complexity
We analyze lottery-choice data in a way that separately estimates the effects of risk aversion and complexity aversion. Complexity is represented by the number of different outcomes in the lottery. A finite mixture random effects model is estimated which assumes that a proportion of the population are complexity-neutral. We find that around 33% of the population are complexity-neutral, around 50% complexity-averse, and the remaining 17% are complexity-loving. Subjects who do react to complexity appear to have a bias towards complexity aversion at the start of the experiment, but complexity aversion reduces with experience, to the extent that the average subject is (almost) complexity-neutral by the end of the experiment. Complexity aversion is found to increase with age and to be higher for non-UK students than for UK students. We also find some evidence that, when evaluating complex lotteries, subjects perceive probabilities in accordance with Prospective Reference Theory
Inattentive Consumers in Markets for Services
In an experiment on markets for services, we find that consumers are likely to stick to default tariffs and achieve suboptimal outcomes. We find that inattention to the task of choosing a better tariff is likely to be a substantial problem in addition to any task and tariff complexity effect. The institutional setup on which we primarily model our experiment is the UK electricity and gas markets, and our conclusion is that the new measures by the UK regulator Ofgem to improve consumer outcomes are likely to be of limited impact
Defective dystrophic thymus determines degenerative changes in skeletal muscle.
In Duchenne muscular dystrophy (DMD), sarcolemma fragility and myofiber necrosis produce cellular debris that attract inflammatory cells. Macrophages and T-lymphocytes infiltrate muscles in response to damage-associated molecular pattern signalling and the release of TNF-α, TGF-β and interleukins prevent skeletal muscle improvement from the inflammation. This immunological scenario was extended by the discovery of a specific response to muscle antigens and a role for regulatory T cells (Tregs) in muscle regeneration. Normally, autoimmunity is avoided by autoreactive T-lymphocyte deletion within thymus, while in the periphery Tregs monitor effector T-cells escaping from central regulatory control. Here, we report impairment of thymus architecture of mdx mice together with decreased expression of ghrelin, autophagy dysfunction and AIRE down-regulation. Transplantation of dystrophic thymus in recipient nude mice determine the up-regulation of inflammatory/fibrotic markers, marked metabolic breakdown that leads to muscle atrophy and loss of force. These results indicate that involution of dystrophic thymus exacerbates muscular dystrophy by altering central immune tolerance
Congruent responses of vascular plant and ant communities to pastoral land-use abandonment in mountain areas throughout different biogeographic regions
On reminder effects, drop-outs and dominance: evidence from an online experiment on charitable giving
We present the results of an experiment that (a) shows the usefulness of screening out drop-outs and (b) tests whether different methods of payment and reminder intervals affect charitable giving. Following a lab session, participants could make online donations to charity for a total duration of three months. Our procedure justifying the exclusion of drop-outs consists in requiring participants to collect payments in person flexibly and as known in advance and as highlighted to them later. Our interpretation is that participants who failed to collect their positive payments under these circumstances are likely not to satisfy dominance. If we restrict the sample to subjects who did not drop out, but not otherwise, reminders significantly increase the overall amount of charitable giving. We also find that weekly reminders are no more effective than monthly reminders in increasing charitable giving, and that, in our three months duration experiment, standing orders do not increase giving relative to one-off donations
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