fNIRS neuroimaging in olfactory research: A systematic literature review

There are a number of key features which make olfaction difficult to study; subjective processes of odor detection, discrimination and identification, and individualistic odor hedonic perception and associated odor memories. In this systematic review we explore the role functional near-infrared spectroscopy (fNIRS) has played in understanding olfactory perception in humans. fNIRS is an optical neuroimaging technique able to measure changes in brain hemodynamics and oxygenation related to neural electrical activity. Adhering to PRISMA guidelines, results of this search found that generally the majority of studies involving healthy adult subjects observed increased activity in response to odors. Other population types were also observed, such as infants, individuals with autism, attention deficit hyperactivity disorder (ADHD), post-traumatic stress disorder (PTSD), mild cognitive impairment (MCI) and dysosmia. fNIRS coverage heavily favored the prefrontal cortex, temporal and parietal regions. This review finds that odor induced cortical activation is dependent on multiple factors, such as odorant type, gender and population type. This review also finds that there is room for improvement in areas such as participant diversity, use of wearable fNIRS systems, physiological monitoring and multi-distance channels

Local and nonlocal solvable structures in ODEs reduction

Solvable structures, likewise solvable algebras of local symmetries, can be used to integrate scalar ODEs by quadratures. Solvable structures, however, are particularly suitable for the integration of ODEs with a lack of local symmetries. In fact, under regularity assumptions, any given ODE always admits solvable structures even though finding them in general could be a very difficult task. In practice a noteworthy simplification may come by computing solvable structures which are adapted to some admitted symmetry algebra. In this paper we consider solvable structures adapted to local and nonlocal symmetry algebras of any order (i.e., classical and higher). In particular we introduce the notion of nonlocal solvable structure

Few cycle pulse propagation

We present a comprehensive framework for treating the nonlinear interaction of few-cycle pulses using an envelope description that goes beyond the traditional SVEA method. This is applied to a range of simulations that demonstrate how the effect of a $\chi^{(2)}$ nonlinearity differs between the many-cycle and few-cycle cases. Our approach, which includes diffraction, dispersion, multiple fields, and a wide range of nonlinearities, builds upon the work of Brabec and Krausz[1] and Porras[2]. No approximations are made until the final stage when a particular problem is considered. The original version (v1) of this arXiv paper is close to the published Phys.Rev.A. version, and much smaller in size.Comment: 9 pages, 14 figure

On the relation between standard and μ\mu-symmetries for PDEs

We give a geometrical interpretation of the notion of $\mu$-prolongations of vector fields and of the related concept of $\mu$-symmetry for partial differential equations (extending to PDEs the notion of $\lambda$-symmetry for ODEs). We give in particular a result concerning the relationship between $\mu$-symmetries and standard exact symmetries. The notion is also extended to the case of conditional and partial symmetries, and we analyze the relation between local $\mu$-symmetries and nonlocal standard symmetries.Comment: 25 pages, no figures, latex. to be published in J. Phys.

Adherence to Mediterranean diet, physical activity level, and severity of periodontitis: Results from a university-based cross-sectional study

Background: The aim of this study was to evaluate the association between adherence to Mediterranean diet (MD) and physical activity (PA) level with the periodontal status of a University-based cohort of individuals. Methods: A total of 235 individuals were included in the study. MD adherence and PA level were registered through validated questionnaires, together with a full periodontal examination. Crude and adjusted odds ratios (ORs) [95% confidence interval] were calculated to evaluate the association between MD adherence, PA level, and periodontitis severity. A final logistic multivariate regression model was built to evaluate the impact of the combination between low MD adherence and low PA level on the prevalence of Stage III/IV periodontitis. Results: The adjusted ORs for Stage III/IV periodontitis were 1.65 [0.84 to 3.28; P = 0.42] for low PA and 5.63 [3.21 to 9.84; P = 0.00] for low MD adherence. The final logistic multivariate regression model resulted in OR = 10.23 [4.01, 26.09; P = 0.00] of having Stage III/IV periodontitis in individuals with low MD adherence and low PA. Conclusions: Individuals conducting a lifestyle characterized by the combination of low MD adherence and lack of regular exercise had 10 times the odds to have severe forms of periodontitis. © 2022 The Author

Beach monitoring and morphological response in the presence of coastal defense strategies at riccione (Italy)

The coastal area at Riccione, in the southern Emilia-Romagna littoral region, is exposed to erosive processes, which are expected to be enhanced by climate change. The beach, mostly composed of fine sand, is maintained through various defense strategies, including frequent nourishment interventions for balancing the sediment deficit and other experimental solutions for reducing coastal erosion. Artificial reshaping of the beach and \u201ccommon practices\u201d in the sediment management redefine the beach morphology and the sediment redistribution almost continuously. These activities overlap each other and with the coastal dynamics, and this makes it very difficult to evaluate their effectiveness, as well as the role of natural processes on the beach morphological evolution. Topo-bathymetric and sedimentological monitoring of the beach has been carried out on a regular basis since 2000 by the Regional Agency for Prevention, Environment and Energy of Emilia-Romagna (Arpae). Further monitoring of the emerged and submerged beach has been carried out in 2019\u20132021 in the framework of the research project STIMARE, focusing on innovative strategies for coastal monitoring in relation with erosion risk. The aim of this study is to assess the coastal behavior at the interannual/seasonal scale in the southern coastal stretch of Riccione, where the adopted coastal defense strategies and management actions mostly control the morphological variations in the emerged and submerged beach besides the wave and current regime. The topo-bathymetric variations and erosion/accretion patterns provided by multitemporal monitoring have been related to natural processes and to anthropogenic activities. The morphological variations have been also assessed in volumetric terms in the different subzones of the beach, with the aim of better understanding the onshore/offshore sediment exchange in relation with nourishments and in the presence of protection structures. The effectiveness of the adopted interventions to combat erosion, and to cope with future climate change-related impacts, appears not fully successful in the presence of an overall sediment deficit at the coast. This demonstrates the need for repeated monitoring of the emerged and submerged beach in such a critical setting

Nonlocal aspects of λ\lambda-symmetries and ODEs reduction

A reduction method of ODEs not possessing Lie point symmetries makes use of the so called $\lambda$-symmetries (C. Muriel and J. L. Romero, \emph{IMA J. Appl. Math.} \textbf{66}, 111-125, 2001). The notion of covering for an ODE $\mathcal{Y}$ is used here to recover $\lambda$-symmetries of $\mathcal{Y}$ as nonlocal symmetries. In this framework, by embedding $\mathcal{Y}$ into a suitable system $\mathcal{Y}^{\prime}$ determined by the function $\lambda$, any $\lambda$-symmetry of $\mathcal{Y}$ can be recovered by a local symmetry of $\mathcal{Y}^{\prime}$. As a consequence, the reduction method of Muriel and Romero follows from the standard method of reduction by differential invariants applied to $\mathcal{Y}^{\prime}$.Comment: 13 page

Symmetries of the Dirac operators associated with covariantly constant Killing-Yano tensors

The continuous and discrete symmetries of the Dirac-type operators produced by particular Killing-Yano tensors are studied in manifolds of arbitrary dimensions. The Killing-Yano tensors considered are covariantly constant and realize certain square roots of the metric tensor. Such a Killing-Yano tensor produces simultaneously a Dirac-type operator and the generator of a one-parameter Lie group connecting this operator with the standard Dirac one. The Dirac operators are related among themselves through continuous or discrete transformations. It is shown that the groups of the continuous symmetry can be only U(1) and SU(2), specific to (hyper-)Kahler spaces, but arising even in cases when the requirements for these special geometries are not fulfilled. The discrete symmetries are also studied obtaining the discrete groups Z_4 and Q. The briefly presented examples are the Euclidean Taub-NUT space and the Minkowski spacetime.Comment: 27 pages, latex, no figures, final version to be published in Class. Quantum Gravit

Towards the theory of integrable hyperbolic equations of third order

The examples are considered of integrable hyperbolic equations of third order with two independent variables. In particular, an equation is found which admits as evolutionary symmetries the Krichever--Novikov equation and the modified Landau--Lifshitz system. The problem of choice of dynamical variables for the hyperbolic equations is discussed.Comment: 22