2,313 research outputs found
Multidimensional persistent homology is stable
Multidimensional persistence studies topological features of shapes by
analyzing the lower level sets of vector-valued functions. The rank invariant
completely determines the multidimensional analogue of persistent homology
groups. We prove that multidimensional rank invariants are stable with respect
to function perturbations. More precisely, we construct a distance between rank
invariants such that small changes of the function imply only small changes of
the rank invariant. This result can be obtained by assuming the function to be
just continuous. Multidimensional stability opens the way to a stable shape
comparison methodology based on multidimensional persistence.Comment: 14 pages, 3 figure
A Multi-Criteria Analysis for the Evaluation of Social Housing Proposals: from the Analytic Hierarchy Process (AHP) to the Analytic Network Process (ANP)
Social housing requires appropriate evaluation models of projects, considering them from multiple perspectives: architectural, technical, environmental, economic, financial, paying particular attention to social aspects. The study proposes the use of a multi criteria evaluation model, based on the hierarchical (AHP) and network (ANP) analysis, as support in decision-making to guide practitioners and policy on the choice among alternative interventions. These methods allow to consider the overall effect of projects on urban system and the different points of view of those concerned, in an integrated and participatory approach. Interesting research perspectives concern the application of these evaluation approaches to case studies related to neighborhoods in which urban planning provides for social housing. The analysis will address the recent proposals for social housing in the city of Pescara (Italy), and in particular the urban transformation that is expected to achieve by means of the Integrated Urban Development Programme on the south-west of the city, whose regeneration was started by the Community Programme Urban 2. Un’Analisi Multi Criteri per la Valutazione delle Proposte di Housing Sociale: dall’Analytic Hierarchy Process (AHP) all’Analytic Network Process (ANP)I modelli insediativi di social housing richiedono idonei strumenti valutativi degli interventi immobiliari, considerandoli da molteplici punti di vista: architettonici, urbanistici, ambientali, economici, finanziari, con particolare attenzione agli aspetti sociali. Lo studio propone l’impiego di un modello valutativo multicriteri basato sull’analisi gerarchica (AHP) e a rete (ANP), come supporto ai processi decisionali riguardanti la scelta tra interventi alternativi di edilizia residenziale sociale, considerando il loro effetto complessivo sul sistema urbano secondo un approccio integrato e partecipativo.Parole Chiave: analisi multicriteri, edilizia residenziale sociale sostenibile, strutturazione del problema decisional
Tumbled Identities: Negotiating Invisible Disabilities and Sexual Orientation
Produced by The Center on Disability Studies, University of Hawai'i at Manoa, Honolulu, Hawai'i, The Frank Sawyer School of Management, Suffolk University, Boston, Massachusetts, and The School of Social Sciences, The University of of Texas at Dallas, Richardson, Texas for The Society for Disability Studies
Open University vs. Consorzio Nettuno: An Institutional Analysis of Two Technology Enabled Higher Educational Systems
Assuming a rational perspective, the adoption and development of a new organisational technology can be viewed as a way to achieve an higher level of efficiency by finding the best way to fully exploit its potential. In other words, one might sustain that since organisations do initially ignore how to best deal with an innovative technology, they engage in a trial and error learning process that finally leads to the x-efficiency frontier. Once this knowledge is achieved, it will probably be spread around by external agents (e.g. consultants) enabling an imitative process. Thus in the long run all organisations will make almost the same efficient use of a mature organisational technology. In this paper we tried to explore how the same technology (eLearning) has been adopted by two diverse educational organisations. The patterns of development have been studied across time to verify if a progressive convergence has occurred. Results are providing some useful insights on what variables must be paid attention to when transferring a technological organisational innovation in a different settin
Betti numbers in multidimensional persistent homology are stable functions
Multidimensional persistence mostly studies topological features of shapes by analyzing the lower level sets of vector-valued functions, called filtering functions.
As is well known, in the case of scalar-valued filtering functions, persistent homology groups can be studied through their persistent Betti numbers, i.e. the dimensions
of the images of the homomorphisms induced by the inclusions of lower level sets into each other. Whenever such inclusions exist for lower level sets of vector-valued
filtering functions, we can consider the multidimensional analogue of persistent Betti numbers. Varying the lower level sets, we get that persistent Betti numbers can be
seen as functions taking pairs of vectors to the set of non-negative integers. In this paper we prove stability of multidimensional persistent Betti numbers. More precisely,
we prove that small changes of the vector-valued filtering functions imply only small changes of persistent Betti numbers functions. This result can be obtained by assuming
the filtering functions to be just continuous. Multidimensional stability opens the way to a stable shape comparison methodology based on multidimensional persistence. In order to obtain our stability theorem, some other new results are proved for continuous filtering functions. They concern the finiteness of persistent Betti numbers for vector-valued filtering functions, and the representation via persistence diagrams of persistent Betti numbers, as well as their stability, in the case of scalar-valued filtering functions. Finally, from the stability of multidimensional persistent Betti numbers we obtain a lower bound for the natural pseudo-distance
SPIRAL: a Novel Biologically-Inspired Algorithm for Gas/Odor Source Localization in an Indoor Environment with no Strong Airflow
Profiles of VGF peptides in the rat brain and their modulations after Phencyclidine treatment
From the VGF precursor protein originate several low molecular weight peptides, whose distribution in the brain and blood circulation is not entirely known. Among the VGF peptides, those containing the N-terminus portion were altered in the cerebro-spinal fluid (CSF) and hypothalamus of schizophrenia patients. "Hence, we aimed to better investigate the involvement of the VGF peptides in schizophrenia by studying their localization in the brain regions relevant for the disease, and revealing their possible modulations in response to certain neuronal alterations occurring in schizophrenia". We produced antibodies against different VGF peptides encompassing the N-terminus, but also C-terminus-, TLQP-, GGGE- peptide sequences, and the so named NERP-3 and -4. These antibodies were used to carry out specific ELISA and immunolocalization studies while mass spectrometry (MS) analysis was also performed to recognize the intact brain VGF fragments. We used a schizophrenia rat model, in which alterations in the prepulse inhibition (PPI) of the acoustic startle response occurred after PCP treatment. In normal rats, all the VGF peptides studied were distributed in the brain areas examined including hypothalamus, prefrontal cortex, hippocampus, accumbens and amygdaloid nuclei and also in the plasma. By liquid chromatography-high resolution mass, we identified different intact VGF peptide fragments, including those encompassing the N-terminus and the NERPs. PCP treatment caused behavioral changes that closely mimic schizophrenia, estimated by us as a disruption of PPI of the acoustic startle response. The PCP treatment also induced selective changes in the VGF peptide levels within certain brain areas. Indeed, an increase in VGF C-terminus and TLQP peptides was revealed in the prefrontal cortex (p < 0.01) where they were localized within parvoalbumin and tyrosine hydroxylase (TH) containing neurons, respectively. Conversely, in the nucleus accumbens, PCP treatment produced a down-regulation in the levels of VGF C-terminus-, N-terminus- and GGGE- peptides (p < 0.01), expressed in GABAergic- (C-terminus/GGGE) and somatostatin- (N-terminus) neurons. These results confirm that VGF peptides are widely distributed in the brain and modulated in specific areas involved in schizophreni
A randomized comparison trial of two and four-step approaches to teaching Cardio-Pulmonary Reanimation
Background and aim of the work: The treatment of cardiac arrest in an extra-hospital environment improves with the increase in the number of people able to establish an early Cardio-Pulmonary Reanimation (CPR). The main aim of the study was to assess the validity of the two-step method in case of prolonged CPR. Methods: A randomized comparison study was conducted in the University Nursing School of a Northern Italian town, during the 2015/16 academic year, among 60 students, to teach them CPR techniques, through two different teaching methods (4-step and the 2-step of CPR training). The effectiveness of the maneuvers performed on mannequins equipped with skill-meter was verified. Results: Our study did not highlight any significant difference between the two methods of CPR training. The comparison between the two methods regarding their efficacy in practical teaching of CPR, highlighted by this study, proved the validity of both the 4-minute continuous method (1st method) and the 30:2 method (2nd method). Conclusions: The results of the study showed no differences between the 2-step and the 4-step methods, in the effectiveness of cardiac massage. The correct execution of chest compressions during a CPR is the key to increase the patient’s chances of rescue. Research has shown that any interruption in the execution of chest compressions, leads to a progressive reduction of the effectiveness of cardiac massage, with negative consequences on the prognosis of the patient undergoing at CPR
Morphology of extrafloral nectaries of Ailanthus altissima (Mill.) Swingle (Simaroubaceae)
Background and Purpose: Ailanthus altissima (Mill.) Swingle (Tree of Heaven) is a highly invasive, widespread, and widely investigated plant species native to the broader area of China. Extrafloral nectaries are major components of the A. altissima secretory system, but the knowledge of their morphology and role in the tree\u27s physiology is limited. This research aims to explore the morphology of extrafloral nectaries, compare it to previous findings, and discuss their possible role and function.
Materials and Methods: Extrafloral nectaries on leaves have been monitored through different phases of leaf development, from June to August 2015 and 2022. The nectaries\u27 morphology was investigated using Zeiss Axioscope 5 and BOECO BSZ-405 light microscopes, and FEG QUANTA 250 FEI scanning electron microscope, operating at 7 kV and pressure of 60–100 Pa, without samples pretreatment.
Results: Our investigation revealed the absence of earlier reported pores or ducts on the top of the glands. However, it supports one of the first, systematical investigations of A. altissima extrafloral nectaries conducted in Croatia a century ago, which was until recently forgotten by history. We evaluated our findings against prior theories and assessed the nectaries\u27 potential role and purpose in disposing surplus sugars.
Conclusions: The nectar in A. altissima is not secreted via an opening on the leaves but rather through epidermal tissue tearing
467 Update on supra-annular sizing of transcatheter aortic valve prostheses in raphe-type bicuspid aortic valve disease according to the LIRA method
Abstract
Aims
Transcatheter Aortic Valve Replacement (TAVR) in patients with bicuspid aortic valve (BAV) still represents a challenge due to the peculiar anatomy and the lack of consensus for the optimal CT scan sizing method for prosthesis selection. Recent evidences have shown that transcatheter heart valve (THV) anchoring in BAV patients might occur at the raphe-level, known as the LIRA (Level of Implantation at the RAphe) plane. Furthermore, a novel supra-annular sizing method based on the measurement of the perimeter at the raphe-level (LIRA-method) was shown to be safe and effective in 20 consecutive BAV patients with severe aortic stenosis. The purpose of this study was to confirm the safety and the efficacy of the LIRA method in a larger study population.
Methods and results
the LIRA plane method was applied to all consecutive patients with raphe-type BAV disease between November 2018 to September 2021 in our centre. We prospectively sized TAVI prosthesis according to the manufacture recommendations on the basis of baseline CT scan perimeters at the LIRA plane. Post-procedural device success, defined according to Valve Academic Research Consortium-2 (VARC-2) criteria, was evaluated in the overall cohort. Forty-four patients were identified as having a raphe-type BAV disease at pre-TAVI CT scans. Mean patient age was 80 ± 6.2 years and 74% were males; median Society of Thoracic Surgeons (STS) predicted risk of mortality score was 4.3 (3.0–6.5). Three different BAV anatomies (36 patients with BAV type 1 with calcific raphe, 5 patients with BAV type 1 with fibrotic raphe, and 3 patients with BAV type 2) were implanted with different types of TAVI prostheses (6 Acurate Neo 2,16 Acurate Neo, 21 Core Valve Evolut R/Pro , 1 Lotus) sized prospectively according to the LIRA plane method. In all patients, there was a significant discrepancy between LIRA and virtual basal ring (VBR) measurements with LIRA plane perimeter smaller than VBR perimeter (mean perimeter LIRA 73.1 ± 8.3 mm vs. mean perimeter VBR 81.5 ± 6.6 mm; P < 0.001). The prostheses were sized according to the manufacture recommendations on the basis of the LIRA plane perimeter (diameter prosthesis implanted/diameter prosthesis according to LIRA plane = 1) (DPI/DP LIRA = 1) and significantly downsized according to the VBR perimeter (DPI/DP VBR 0.89; P < 0.001). The median prosthesis size was 25 mm (23–27). Pre-dilatation was frequently performed (86%) with a median balloon size of 20 mm (18–22), whereas post-dilatation was applied in 27% of the cases with a median balloon size of 23 mm (20–26). The LIRA plane method appeared to be highly successful (100% VARC-2 device success) with no procedural mortality, no valve migration, residual trivial/mild paravalvular leak with no cases of moderate-severe regurgitation and low transprosthetic gradient (residual mean gradient of 8.3 ± 3.5 mmHg) with no cases of mean gradient >20 mmHg pre-discharge. The rate of new pacemaker implantation was 9%.
Conclusions
Supra-annular sizing according to the LIRA plane method confirmed to be safe with a high device success in a larger study population. The application of the LIRA plane method might optimize TAVI prosthesis sizing in patients with raphe-type BAV disease
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