862 research outputs found
Correlation Clustering with Adaptive Similarity Queries
In correlation clustering, we are given objects together with a binary
similarity score between each pair of them. The goal is to partition the
objects into clusters so to minimise the disagreements with the scores. In this
work we investigate correlation clustering as an active learning problem: each
similarity score can be learned by making a query, and the goal is to minimise
both the disagreements and the total number of queries. On the one hand, we
describe simple active learning algorithms, which provably achieve an almost
optimal trade-off while giving cluster recovery guarantees, and we test them on
different datasets. On the other hand, we prove information-theoretical bounds
on the number of queries necessary to guarantee a prescribed disagreement
bound. These results give a rich characterization of the trade-off between
queries and clustering error
Just another roll of the dice: a socially creative initiative to assure Roma housing in North Western Italy
This chapter concerns how social innovation relates to the social production of space. Usually, the scholarly literature on local welfare, social work, and ‘social cohesion’ at the urban level mostly fails to consider the relevance of space. The spatial dimension of a socially creative strategy is constituted in physical and symbolic boundaries, in the built environment, in situated objects and relationships. Space can significantly contribute to stigma and exclusion, notably in segregated places. In fact, space performs: it has social effects on people’s opportunities and on their self-esteem . Nonetheless the space is itself a social product; it is the object of strategies. Most social innovators invest in space, trying to shape it, to modify it, to make it more inclusive. They aim to use it as a lever for social innovation. Some such innovations use art as a tool to produce change in the spatial configuration for deprived groups. In this chapter we observe a case of a socially creative strategy in which a par- ticularly difficult housing problem was solved thanks to a holistic approach to the production of space. More specifically, we observed how a network of NGOs was able to manage a situation of housing exclusion for some highly stigmatized roma families. Yet the true character of this social innovation lay precisely at the level of the production of space. The main problem that the network sought to address was the issue of segregation that housing for roma usually reproduces. Welfare provisions for roma in Italy are traditionally part of the problem they are supposed to solve: they maintain segregation and fail to support roma inclusion in broader urban life. This network therefore decided to design a project and implement it in a very collab- orative way. They did not provide a specialized shelter for evicted roma people, or for roma housing emergencies; rather, they invented a participative path within the Turin metropolitan area to produce a space that could also, but not exclusively, welcome Roma families, without labelling them and without separating them from the wider local community
Influence of the listening context on the perceived realism of binaural recordings
Binaural recordings and audio are becoming an interesting resource for composers, live performances and augmented reality. This paper focuses on the acceptance and the perceived quality by the audience of such spatial recordings. We present the results of a preliminary study of psychoacoustic perception where N=26 listeners had to report on the realism and the quality of different couples of sounds taken from two different rooms with peculiar reverb. Sounds are recorded with a self-made dummy head. The stimuli are grouped into classes with respects to some characteristics highlighted as potentially important for the task. Listening condition is fixed with headphones. Participants are divided into musically trained and naive subjects. Results show that there exists differences between the two groups of participants and that the “semantic relevance” of a sound plays a central role
The effects of vent location, event scale and time forecasts on pyroclastic density current hazard maps at Campi Flegrei caldera (Italy)
This study presents a new method for producing long-term hazard maps for pyroclastic
density currents (PDC) originating at Campi Flegrei caldera. Such method is based on
a doubly stochastic approach and is able to combine the uncertainty assessments on
the spatial location of the volcanic vent, the size of the flow and the expected time of
such an event. The results are obtained by using a Monte Carlo approach and adopting
a simplified invasion model based on the box model integral approximation. Temporal
assessments are modeled through a Cox-type process including self-excitement effects,
based on the eruptive record of the last 15 kyr.Mean and percentilemaps of PDC invasion
probability are produced, exploring their sensitivity to some sources of uncertainty and to
the effects of the dependence between PDC scales and the caldera sector where they
originated. Conditional maps representative of PDC originating inside limited zones of the
caldera, or of PDC with a limited range of scales are also produced. Finally, the effect of
assuming different time windows for the hazard estimates is explored, also including the
potential occurrence of a sequence of multiple events. Assuming that the last eruption
of Monte Nuovo (A.D. 1538) marked the beginning of a new epoch of activity similar to
the previous ones, results of the statistical analysis indicate a mean probability of PDC
invasion above 5% in the next 50 years on almost the entire caldera (with a probability
peak of 25% in the central part of the caldera). In contrast, probability values reduce
by a factor of about 3 if the entire eruptive record is considered over the last 15 kyr, i.e.,
including both eruptive epochs and quiescent periods
Type I Collagen and Strontium-Containing Mesoporous Glass Particles as Hybrid Material for 3D Printing of Bone-Like Materials
Bone tissue engineering offers an alternative promising solution to treat a large number of
bone injuries with special focus on pathological conditions, such as osteoporosis. In this scenario,
the bone tissue regeneration may be promoted using bioactive and biomimetic materials able to
direct cell response, while the desired scaffold architecture can be tailored by means of 3D printing
technologies. In this context, our study aimed to develop a hybrid bioactive material suitable for 3D
printing of scaffolds mimicking the natural composition and structure of healthy bone. Type I collagen
and strontium-containing mesoporous bioactive glasses were combined to obtain suspensions able
to perform a sol-gel transition under physiological conditions. Field emission scanning electron
microscopy (FESEM) analyses confirmed the formation of fibrous nanostructures homogeneously
embedding inorganic particles, whereas bioactivity studies demonstrated the large calcium phosphate
deposition. The high-water content promoted the strontium ion release from the embedded glass
particles, potentially enhancing the osteogenic behaviour of the composite. Furthermore, the
suspension printability was assessed by means of rheological studies and preliminary extrusion tests,
showing shear thinning and fast material recovery upon deposition. In conclusion, the reported
results suggest that promising hybrid systems suitable for 3D printing of bioactive scaffolds for bone
tissue engineering have been developed
Correlation Clustering with Adaptive Similarity Queries
In correlation clustering, we are given n objects together with a binary similarity
score between each pair of them. The goal is to partition the objects into clusters
so to minimise the disagreements with the scores. In this work we investigate
correlation clustering as an active learning problem: each similarity score can be
learned by making a query, and the goal is to minimise both the disagreements
and the total number of queries. On the one hand, we describe simple active
learning algorithms, which provably achieve an almost optimal trade-off while
giving cluster recovery guarantees, and we test them on different datasets. On the
other hand, we prove information-theoretical bounds on the number of queries
necessary to guarantee a prescribed disagreement bound. These results give a rich
characterization of the trade-off between queries and clustering erro
COX-1 Inhibitors: Beyond Structure Toward Therapy
Biosynthesis of prostaglandins from arachidonic acid (AA) is catalyzed by cyclooxygenase (COX), which exists as COX-1 and COX-2. AA is in turn released from the cell membrane upon neopathological stimuli. COX inhibitors interfere in this catalytic and disease onset process. The recent prominent discovery involvements of COX-1 are mainly in cancer and inflammation. Five classes of COX-1 inhibitors are known up to now and this classification is based on chemical features of both synthetic compounds and substances from natural sources. Physicochemical interactions identification between such molecules and COX-1 active site was achieved through X-ray, mutagenesis experiments, specific assays and docking investigations, as well as through a pharmacometric predictive model building. All these insights allowed the design of new highly selective COX-1 inhibitors to be tested into those disease models in which COX-1 is involved. Particularly, COX-1 is expressed at high levels in the early to advanced stages of human epithelial ovarian cancer, and it also seems to play a pivotal role in cancer progression. The refinement of COX-1 selective inhibitor structure has progressed to the stage that some of the inhibitors described in this review could be considered as promising active principle ingredients of drugs and hence part of specific therapeutic protocols. This review aims to outline achievements, in the last 5 years, dealing with the identification of highly selective synthetic and from plant extracts COX-1 inhibitors and their theranostic use in neuroinflammation and ovarian cancer. Their gastrotoxic effect is also discussed
The oncogenic role of circPVT1 in head and neck squamous cell carcinoma is mediated through the mutant p53/YAP/TEAD transcription-competent complex
Background: Circular RNAs are a class of endogenous RNAs with various functions in eukaryotic cells. Worthy of note, circular RNAs play a critical role in cancer. Currently, nothing is known about their role in head and neck squamous cell carcinoma (HNSCC). The identification of circular RNAs in HNSCC might become useful for diagnostic and therapeutic strategies in HNSCC.
Results: Using samples from 115 HNSCC patients, we find that circPVT1 is over-expressed in tumors compared to matched non-tumoral tissues, with particular enrichment in patients with TP53 mutations. circPVT1 up-and down-regulation determine, respectively, an increase and a reduction of the malignant phenotype in HNSCC cell lines. We show that circPVT1 expression is transcriptionally enhanced by the mut-p53/YAP/TEAD complex. circPVT1 acts as an oncogene modulating the expression of miR-497-5p and genes involved in the control of cell proliferation.
Conclusions: This study shows the oncogenic role of circPVT1 in HNSCC, extending current knowledge about the role of circular RNAs in cancer
Enhancement of radiosensitivity by the novel anticancer quinolone derivative vosaroxin in preclinical glioblastoma models
Purpose: Glioblastoma multiforme (GBM) is the most aggressive brain tumor. The activity of vosaroxin, a first-in-class anticancer quinolone derivative that intercalates DNA and inhibits topoisomerase II, was investigated in GBM preclinical models as a single agent and combined with radiotherapy (RT). Results: Vosaroxin showed antitumor activity in clonogenic survival assays, with IC50 of 10-100 nM, and demonstrated radiosensitization. Combined treatments exhibited significantly higher γH2Ax levels compared with controls. In xenograft models, vosaroxin reduced tumor growth and showed enhanced activity with RT; vosaroxin/RT combined was more effective than temozolomide/RT. Vosaroxin/ RT triggered rapid and massive cell death with characteristics of necrosis. A minor proportion of treated cells underwent caspase-dependent apoptosis, in agreement with in vitro results. Vosaroxin/RT inhibited RT-induced autophagy, increasing necrosis. This was associated with increased recruitment of granulocytes, monocytes, and undifferentiated bone marrow-derived lymphoid cells. Pharmacokinetic analyses revealed adequate blood-brain penetration of vosaroxin. Vosaroxin/RT increased disease-free survival (DFS) and overall survival (OS) significantly compared with RT, vosaroxin alone, temozolomide, and temozolomide/RT in the U251-luciferase orthotopic model. Materials and Methods: Cellular, molecular, and antiproliferative effects of vosaroxin alone or combined with RT were evaluated in 13 GBM cell lines. Tumor growth delay was determined in U87MG, U251, and T98G xenograft mouse models. (DFS) and (OS) were assessed in orthotopic intrabrain models using luciferasetransfected U251 cells by bioluminescence and magnetic resonance imaging. Conclusions: Vosaroxin demonstrated significant activity in vitro and in vivo in GBM models, and showed additive/synergistic activity when combined with RT in O6- methylguanine methyltransferase-negative and -positive cell lines
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