Structure fractals and para-quaternionic geometry

It is well known that starting with real structure, the Cayley-Dickson process gives complex, quaternionic, and octonionic (Cayley) structures related to the Adolf Hurwitz composition formula for dimensions $p = 2, 4$ and $8$, respectively, but the procedure fails for $p = 16$ in the sense that the composition formula involves no more a triple of quadratic forms of the same dimension; the other two dimensions are $n = 2^7$. Instead, Ławrynowicz and Suzuki (2001) have considered graded fractal bundles of the flower type related to complex and Pauli structures and, in relation to the iteration process $p \to p + 2 \to p + 4 \to ...$, they have constructed $2^4$-dimensional “bipetals” for $p = 9$ and $2^7$-dimensional “bisepals” for $p = 13$. The objects constructed appear to have an interesting property of periodicity related to the gradating function on the fractal diagonal interpreted as the “pistil” and a family of pairs of segments parallel to the diagonal and equidistant from it, interpreted as the “stamens”. The first named author, M. Nowak-Kepczyk, and S. Marchiafava (2006, 2009a, b) gave an effective, explicit determination of the periods and expressed them in terms of complex and quaternionic structures, thus showing the quaternionic background of that periodicity. In contrast to earlier results, the fractal bundle flower structure, in particular petals, sepals, pistils, and stamens are not introduced ab initio; they are quoted a posteriori, when they are fully motivated. Physical concepts of dual and conjugate objects as well as of antiparticles led us to extend the periodicity theorem to structure fractals in para-quaternionic formulation, applying some results in this direction by the second named author. The paper is concluded by outlining some applications

Subspaces of a para-quaternionic Hermitian vector space

Let $(\tilde Q,g)$ be a para-quaternionic Hermitian structure on the real vector space $V$. By referring to the tensorial presentation $(V, \tilde{Q},g) \simeq (H^2 \otimes E^{2n}, \mathfrak{sl}(H),\omega^H \otimes \omega^E)$, we give an explicit description, from an affine and metric point of view, of main classes of subspaces of $V$ which are invariantly defined with respect to the structure group of $\tilde{Q}$ and $(\tilde{Q},g)$ respectively

Local degradation of selectively oxidized AlGaAs/AlAs distributed Bragg reflectors in lateral-injection vertical-cavity surface-emitting lasers

We show the local degradation of a selectively oxidized top distributed Bragg reflector (DBR) in a lateral-junction vertical-cavity surface-emitting laser (LJ-VCSEL) working at room temperature in continuous-wave operation. The measurements were carried out by a scanning microluminescence system used in reflection mode. The injection of a few milliamps in continuous-wave operation at room temperature in the LJ-VCSEL induces damage both in the DBRs and in the active area. The submicron resolution maps of the reflected laser intensity, recorded from the top surface of the LJ-VCSEL, show a strong local change in the top DBR reflectivity before and after current injection. The μ-photoluminescence map, recorded after the device failure, shows that the radiative recombination is strongly decreased in the damaged area of the device

A review of the enabling methodologies for knowledge discovery from smart grids data

The large-scale deployment of pervasive sensors and decentralized computing in modern smart grids is expected to exponentially increase the volume of data exchanged by power system applications. In this context, the research for scalable and flexible methodologies aimed at supporting rapid decisions in a data rich, but information limited environment represents a relevant issue to address. To this aim, this paper investigates the role of Knowledge Discovery from massive Datasets in smart grid computing, exploring its various application fields by considering the power system stakeholder available data and knowledge extraction needs. In particular, the aim of this paper is dual. In the first part, the authors summarize the most recent activities developed in this field by the Task Force on “Enabling Paradigms for High-Performance Computing in Wide Area Monitoring Protective and Control Systems” of the IEEE PSOPE Technologies and Innovation Subcommittee. Differently, in the second part, the authors propose the development of a data-driven forecasting methodology, which is modeled by considering the fundamental principles of Knowledge Discovery Process data workflow. Furthermore, the described methodology is applied to solve the load forecasting problem for a complex user case, in order to emphasize the potential role of knowledge discovery in supporting post processing analysis in data-rich environments, as feedback for the improvement of the forecasting performances

Glucosylceramidase Mass and Subcellular Localization Are Modulated by Cholesterol in Niemann-Pick Disease Type C

Niemann-Pick disease type C (NPC) is characterized by the accumulation of cholesterol and sphingolipids in the late endosomal/lysosomal compartment. The mechanism by which the concentration of sphingolipids such as glucosylceramide is increased in this disease is poorly understood. We have found that, in NPC fibroblasts, the cholesterol storage affects the stability of glucosylceramidase (GCase), decreasing its mass and activity; a reduction of cholesterol raises the level of GCase to nearly normal values. GCase is activated and stabilized by saposin C (Sap C) and anionic phospholipids. Here we show by immunofluorescence microscopy that in normal fibroblasts, GCase, Sap C, and lysobisphosphatidic acid (LBPA), the most abundant anionic phospholipid in the endolysosomal system, reside in the same intracellular vesicular structures. In contrast, the colocalization of GCase, Sap C, and LBPA is markedly impaired in NPC fibroblasts but can be re-established by cholesterol depletion. These data show for the first time that the level of cholesterol modulates the interaction of GCase with its protein and lipid activators, namely Sap C and LBPA, regulating the GCase activity and stability

Do Lifestyle Interventions before Gastric Bypass Prevent Weight Regain after Surgery? A Five-Year Longitudinal Study

It is unclear whether weight loss (WL) achieved by means of lifestyle interventions (LSIs) before bariatric surgery (BS) can improve long-term WL outcomes after surgery. We aimed to assess the impact of a structured LSI on WL% after gastric bypass (GBP). Two groups of patients were selected from a large cohort of participants with obesity who underwent GBP surgery at Santa Maria Nuova Hospital (Reggio Emilia, Italy). The groups were categorized as those who have or have not received LSI prior to GBP. The LSI group included 91 participants (cases) compared to 123 participants (controls) in the non-LSI group. WL% was measured at follow-up times of 1, 3, 6, 12, 24, 36, 48, and 60 months. The LSI group achieved a clinically significant WL% (-7.5%) before BS, and at the time of surgery, the two groups had similar body weights and demographic statuses. At all points, until the 24-month follow-up, the two groups displayed similar WLs%. With regard to the longer follow-ups, the LSI group maintained weight loss until the last timepoint (60 months), whereas the non-LSI group experienced weight regain at 36, 48, and 60 months. In a real-world context, a structured behavioral LSI prior to GBP seems to prevent longer-term weight regain

The secretion and maturation of prosaposin and procathepsin D are blocked in embryonic neural progenitor cells

The notion that prosaposin (Prosap) is likely involved in brain development and regeneration led us to explore its expression in stem/progenitor neural cells and its fate after cell differentiation. The expression of procathepsin-cathepsin D (proCath-Cath D), an endoprotease that plays an important role in the processing and sorting of Prosap, has been concomitantly examined. Our data evidenced that in embryonic human neural progenitor cells (eHNPCs) intact and high molecular weight intermediate forms of Prosap and intermediate forms of Cath D accumulated inside the cells, while the formation of saposins and mature Cath D was impaired. Furthermore, neither Prosap nor proCath D were secreted from eHNPCs. The block of the processing and secretion shared by Prosap and proCath D was overcome during the course of differentiation of eHNPCs into a mixed population of astrocytes and neuronal cells. Upon differentiation, large amounts of Prosap and proCath D were secreted from the cells, while saposins and mature Cath D were produced inside the cells. The dramatic accumulation of Prosap (an antiapoptotic factor) and reduction of mature Cath D (a proapoptotic factor) in the undifferentiated eHNPCs most likely play a role in the molecular mechanisms regulating the resistance to apoptotic signals of these cells and might represent a critically important issue in HNPCs biology. © 2008 Elsevier B.V. All rights reserved

Cyclic Peptoids as Mycotoxin Mimics: An Exploration of Their Structural and Biological Properties

Cyclic peptoids have recently emerged as important examples of peptidomimetics for their interesting complexing properties and innate ability to permeate biological barriers. In the present contribution, experimental and theoretical data evidence the intricate conformational and stereochemical properties of five novel hexameric peptoids decorated with N-isopropyl, N-isobutyl, and N-benzyl substituents. Complexation studies by NMR, in the presence of sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (NaTFPB), theoretical calculations, and single-crystal X-ray analyses indicate that the conformationally stable host/guest metal adducts display architectural ordering comparable to that of the enniatins and beauvericin mycotoxins. Similarly to the natural depsipeptides, the synthetic oligolactam analogues show a correlation between ion transport abilities in artificial liposomes and cytotoxic activity on human cancer cell lines. The reported results demonstrate that the versatile cyclic peptoid scaffold, for its remarkable conformational and complexing properties, can morphologically mimic related natural products and elicit powerful biological activities

L’insediamento a bifacciali di Guado San Nicola (Monteroduni, Molise, Italia)

La monografia rappresenta un compendio di lavori specialistici sul sito paleolitico di Guado San Nicola a Monteroduni (Molise, Italia), oggetto di ricerche sistematiche ed indagini interdisciplinari inaugurate nell’area a partire dal 2000 dall'Università degli Studi di Ferrara. Il sito, ascrivibile al MIS 10/11, costituisce un tassello importante nell’ambito della ricostruzione del quadro del popolamento umano della penisola italiana e dell’intero bacino del Mediterraneo, alla luce delle considerazioni crono-stratigrafiche, della ricchezza della documentazione e della presenza di elementi innovativi dal punto di vista culturale quali la padronanza del metodo Levallois e l’uso di percussori in palchi di cervo