Aquatic insects and benthic diatoms: A history of biotic relationships in freshwater ecosystems

The most important environmental characteristic in streams is flow. Due to the force of water current, most ecological processes and taxonomic richness in streams mainly occur in the riverbed. Benthic algae (mainly diatoms) and benthic macroinvertebrates (mainly aquatic insects) are among the most important groups in running water biodiversity, but relatively few studies have investigated their complex relationships. Here, we review the multifaceted interactions between these two important groups of lotic organisms. As the consumption of benthic algae, especially diatoms, was one of the earliest and most common trophic habits among aquatic insects, they then had to adapt to the particular habitat occupied by the algae. The environmental needs of diatoms have morphologically and behaviorally shaped their scrapers, leading to impressive evolutionary convergences between even very distant groups. Other less evident interactions are represented by the importance of insects, both in preimaginal and adult stages, in diatom dispersion. In addition, the top-down control of diatoms by their grazers contributes to their spatial organization and functional composition within the periphyton. Indeed, relationships between aquatic insects and diatoms are an important topic of study, scarcely investigated, the onset of which, hundreds of millions of years ago, has profoundly influenced the evolution of stream biological communities

Strain-controlled fatigue loading of an additively manufactured AISI 316L steel: Cyclic plasticity model and strain–life curve with a comparison to the wrought material

Low cycle fatigue (LCF) regime was experimentally studied for a 316L steel additively manufactured by laser-powder bed fusion (L-PBF), a material widely used in sectors that require a reliable durability analysis. Material cyclic elastoplastic behavior is described by the Chaboche–Voce combined plasticity model, which displayed a great degree of accuracy. The fatigue life was modeled by both invoking the Manson–Coffin curve and other simplified models derived from static properties of the material; some of which showed remarkably good accuracy. A quantitative comparison with a wrought-processed 316L steel displayed a markedly different cyclic elastoplastic response but comparable fatigue strengths

Experimental and Numerical Investigation of Hot Extruded Inconel 718

Inconel 718 is a widely used superalloy, due to its unique corrosion resistance and mechanical strength properties at very high temperatures. Hot metal extrusion is the most widely used forming technique, if the manufacturing of slender components is required. As the current scientific literature does not comprehensively cover the fundamental aspects related to the process–structure relationships, in the present work, a combined numerical and experimental approach is employed. A finite element (FE) model was established to answer three key questions: (1) predicting the required extrusion force at different extrusion speeds; (2) evaluating the influence of the main processing parameters on the formation of surface cracks using the normalized Cockcroft Latham’s (nCL) damage criterion; and (3) quantitatively assessing the amount of recrystallized microstructure through Avrami’s equation. For the sake of modeling validation, several experimental investigations were carried out under different processing conditions. Particularly, it was found that the higher the initial temperature of the billet, the lower the extrusion force, although a trade-off must be sought to avoid the formation of surface cracks occurring at excessive temperatures, while limiting the required extrusion payload. The extrusion speed also plays a relevant role. Similarly to the role of the temperature, an optimal extrusion speed value must be identified to minimize the possibility of surface crack formation (high speeds) and to minimize the melting of intergranular niobium carbides (low speeds)

Characterization of chenopodin isoforms from quinoa seeds and assessment of their potential anti-inflammatory activity in Caco-2 cells

Several food-derived molecules, including proteins and peptides, can show bioactivities toward the promotion of well-being and disease prevention in humans. There is still a lack of information about the potential effects on immune and inflammatory responses in mammalian cells following the ingestion of seed storage proteins. This study, for the first time, describes the potential immunomodulation capacity of chenopodin, the major protein component of quinoa seeds. After characterizing the molecular features of the purified protein, we were able to separate two different forms of chenopodin, indicated as LcC (Low charge Chenopodin, 30% of total chenopodin) and HcC (High charge Chenopodin, 70% of total chenopodin). The biological effects of LcC and HcC were investigated by measuring NF-\u3baB activation and IL-8 expression studies in undifferentiated Caco-2 cells. Inflammation was elicited using IL-1\u3b2. The results indicate that LcC and HcC show potential anti-inflammatory activities in an intestinal cell model, and that the proteins can act differently, depending on their structural features. Furthermore, the molecular mechanisms of action and the structural/functional relationships of the protein at the basis of the observed bioactivity were investigated using in silico analyses and structural predictions

Microstructure and residual stress evolution during cyclic elastoplastic deformation of AISI316L fabricated via laser powder bed fusion

In metal additive manufacturing (MAM), microstructural properties such as texture, residual stresses, and dislocation density have emerged as key factors ruling the resulting mechanical performances. In this study, cylindrical AISI 316L specimens, fabricated with laser powder bed fusion (LPBF), were tested under cyclic elastoplastic (EP) deformation using a constant strain amplitude to highlight the evolution of residual stresses (RS), dislocation density and texture with increasing number of EP cycles, N, across the hardening-softening (H–S) transition stage, in the attempt to find correlations between relevant microstructural parameters and macroscopic properties. The structural and microstructural analysis is carried out through whole powder pattern modeling (WPPM) of neutron diffraction (ND) data and Electron Back-Scattering Diffraction (EBSD) analysis. The H–S transition is found to occur within 7–9 cycles, with RS fading out already after 5 cycles. Across the H–S transition, the trend of the maximum tensile stress correlates closely with the trend of WPPM-calculated total dislocation density, suggesting a major role of dislocations’ characteristics in the evolution of macroscopic mechanical properties. EBSD analysis reveals the rearrangement of geometrically necessary dislocations (GND) into cellular structures, and moderate grain refinement, which are deemed to be responsible for the quick fading of RS in the very early stage of EP loading. ND-based texture analysis reveals a (220) preferential orientation retained throughout the EP tests but with orientation density functions (ODFs) changing non-monotonically with N, suggesting preliminary partial randomization of grains around the deformation axis followed by the recovery of crystallographic anisotropy and more localized ODFs

Seismic activity in the Pollino region (Basilicata-Calabria border)

The Pollino region and the whole Calabria-Lucania border are known for the absence of destructive (M>6) historical earthquakes. This lack of historical seismicity is noticeable in the analysis of Southern Apennines and Calabria earthquake history (Rovida et al., 2011). At the same time, paleoseismological studies found evidence for significant active faulting (Cinti et al., 1997; Michetti et al., 1997) pointing to the Pollino area as a seismic gap. Instrumental seismicity in the region is characterized by the occurrence of seismic sequences, one of the most significant in the last decades is the Mercure seismic sequence, Mw 5.6 in September 1998 (Brozzetti et al., 2008). For this reason, the sequence started in 2010 raised a big concern in the population and local authorities. INGV is following the evolution of the sequence since its beginning, in March 2010, increasing the seismic monitoring and planning several activities and projects. The area was proposed by INGV to DPC (Dipartimento di Protezione Civile nazionale) for inclusion in the projects to be carried out in the present INGV-DPC agreement. This project has just started and will try to provide better constraints to the active tectonics and fault identification of the region. In this paper we describe what INGV is doing to understand better the tectonics of the region using microseismicity, and try to offer some cue to the discussion about the seismogenic faults in the area.Published5-92T. Tettonica attivaN/A or not JCRope

The Unified Method: I Non-Linearizable Problems on the Half-Line

Boundary value problems for integrable nonlinear evolution PDEs formulated on the half-line can be analyzed by the unified method introduced by one of the authors and used extensively in the literature. The implementation of this general method to this particular class of problems yields the solution in terms of the unique solution of a matrix Riemann-Hilbert problem formulated in the complex $k$-plane (the Fourier plane), which has a jump matrix with explicit $(x,t)$-dependence involving four scalar functions of $k$, called spectral functions. Two of these functions depend on the initial data, whereas the other two depend on all boundary values. The most difficult step of the new method is the characterization of the latter two spectral functions in terms of the given initial and boundary data, i.e. the elimination of the unknown boundary values. For certain boundary conditions, called linearizable, this can be achieved simply using algebraic manipulations. Here, we present an effective characterization of the spectral functions in terms of the given initial and boundary data for the general case of non-linearizable boundary conditions. This characterization is based on the analysis of the so-called global relation, on the analysis of the equations obtained from the global relation via certain transformations leaving the dispersion relation of the associated linearized PDE invariant, and on the computation of the large $k$ asymptotics of the eigenfunctions defining the relevant spectral functions.Comment: 39 page

Nonlinear interfacial waves in a constant-vorticity planar flow over variable depth

Exact Lagrangian in compact form is derived for planar internal waves in a two-fluid system with a relatively small density jump (the Boussinesq limit taking place in real oceanic conditions), in the presence of a background shear current of constant vorticity, and over arbitrary bottom profile. Long-wave asymptotic approximations of higher orders are derived from the exact Hamiltonian functional in a remarkably simple way, for two different parametrizations of the interface shape.Comment: revtex, 4.5 pages, minor corrections, summary added, accepted to JETP Letter

Cama de frango como substrato para a produção de biogás após diferentes períodos de estocagem.

RESUMO: Na avicultura a cama de frango é produzida sazonalmente, em função do modo de produção. Para obter energia do biogás por meio da biodigestão da cama de frango, de forma contínua, o armazenamento do resíduo pode ser uma solução. Ensaios de Potencial Bioquímico de Metano (BMP) foram utilizados neste trabalho para estimar a capacidade de produção de biogás e metano da cama de frango removida após o sexto lote de reutilização e a diferentes tempos de armazenamento após a coleta, assim, verificar a viabilidade de utilização da cama de frango como um substrato em unidade produtora de biogás. A produção de biogás e metano, nas amostras em diferentes períodos de armazenamento, foi comparada: antes de armazenar 245 LN biogas.kgSV adic-1 e 159 LN CH4.kgSV adic-11, seis meses com 252 LN biogas.kgSV adic-1 e 160 LN CH4.kgSV adic-1 e um ano 209 LN biogas.kgSV adic-1 e 117 LNCH4.kgSV adic-1, demonstrando que o período de armazenamento é caracterizado por uma relativa perda do conteúdo de matéria orgânica após um ano, contudo, não há diferença significativa entre a produção de biogás e metano após seis meses armazenada e antes de armazenar. Verificou-se a viabilidade da estocagem de cama de frango do sexto lote de reutilização, no período de seis meses, sem perda significativa de matéria orgânica para a conversão em biogás e metano. ABSTRACT: In poultry litter is produced seasonally due to production mode. To get energy from biogas through the bio digestion of poultry litter, continuously, the storage of the residue can be a solution. Biochemical Methane Potential (BMP) assays were used in this study to estimate the production of biogas and methane poultry litter removed after the sixth lot of reuse and in different storage times after collect, so check the feasibility of use poultry litter as a feedstock in biogas producer unit. The production of biogas and methane in the samples in different periods of storage was compared: before storage 245 LN biogas.kgVS add-1 E 159 LN C H4 kg SV add-1, six months with 252 LN biogas.kgVS add-1 e 160 LN C H4 kg SV add-1 and a year 209 LN biogas.kgVS add-1 and one year 117 LN C H4 kg SV add-1, demonstrating that the storage period is characterized by a relative loss of content of organic matter after a year, however there's no significant difference between the production of biogas and methane in six months storaged and before storage . It was verified the viability of storage of poultry litter of the sixth lot of reuse, in the six-month period, without significant loss of organic matter for conversion to biogas and methane