Propagating and evanescent internal waves in a deep ocean model

We present experimental and computational studies of the propagation of internal waves in a stratified fluid with an exponential density profile that models the deep ocean. The buoyancy frequency profile $N(z)$ (proportional to the square root of the density gradient) varies smoothly by more than an order of magnitude over the fluid depth, as is common in the deep ocean. The nonuniform stratification is characterized by a turning depth $z_c$, where $N(z_c)$ is equal to the wave frequency $\omega$ and $N(z < z_c) < \omega$. Internal waves reflect from the turning depth and become evanescent below the turning depth. The energy flux below the turning depth is shown to decay exponentially with a decay constant given by $k_c$, which is the horizontal wavenumber at the turning depth. The viscous decay of the vertical velocity amplitude of the incoming and reflected waves above the turning depth agree within a few percent with a previously untested theory for a fluid of arbitrary stratification [Kistovich and Chashechkin, J. App. Mech. Tech. Phys. 39, 729-737 (1998)].Comment: 13 pages, 4 figures, 4 table

Isocurvature fluctuations in the effective Newton's constant

We present a new isocurvature mode present in scalar-tensor theories of gravity that corresponds to a regular growing solution in which the energy of the relativistic degrees of freedom and the scalar field that regulates the gravitational strength compensate during the radiation dominated epoch on scales much larger than the Hubble radius. We study this isocurvature mode and its impact on anisotropies of the cosmic microwave background for the simplest scalar-tensor theory, i.e. the extended Jordan-Brans-Dicke gravity, in which the scalar field also drives the acceleration of the Universe. We use Planck data to constrain the amplitude of this isocurvature mode in the case of fixed correlation with the adiabatic mode and we show how this mode could be generated in a simple two field inflation model.Comment: Version updated to match published version. No changes in the result

Identification of the het-r vegetative incompatibility gene of Podospora anserina as a member of the fast evolving HNWD gene family

In fungi, vegetative incompatibility is a conspecific non-self recognition mechanism that restricts formation of viable heterokaryons when incompatible alleles of specific het loci interact. In Podospora anserina, three non-allelic incompatibility systems have been genetically defined involving interactions between het-c and het-d, het-c and het-e, het-r and het-v. het-d and het-e are paralogues belonging to the HNWD gene family that encode proteins of the STAND class. HET-D and HET-E proteins comprise an N-terminal HET effector domain, a central GTP binding site and a C-terminal WD repeat domain constituted of tandem repeats of highly conserved WD40 repeat units that define the specificity of alleles during incompatibility. The WD40 repeat units of the members of this HNWD family are undergoing concerted evolution. By combining genetic analysis and gain of function experiments, we demonstrate that an additional member of this family, HNWD2, corresponds to the het-r non-allelic incompatibility gene. As for het-d and het-e, allele specificity at the het-r locus is determined by the WD repeat domain. Natural isolates show allelic variation for het-

Executive Design of the Façade Systems. Typologies and Technologies of the Advanced Building Envelopes

The study, developed inside the experimental laboratory Material Balance Research within the Architecture, Built Environment and Construction Engineering-ABC Department at the Politecnico di Milano, examines the advanced façade systems according to the constitutive and typological characters, as well as the functional and applicative requirements such as the expressive, constructive and interactive criteria towards the environmental, perceptive and energy conditions. The work involves to examine the typological and technological constitution of the principal advanced façade systems in the contemporary design and experimental scenario, proposing itself as a knowledge and operational tool currently lacking in the technical literature of the sector at an international level. The work considers the field of advanced façade systems in a scientific way, constituting a support for the study and the executive design. Compared to the pre-existing literature on envelope systems, the work investigates in detail, in an analytical form, the constitution of the components on a typological and geometrical, functional and constructive level, on the basis of the documents and knowledges acquired from the essential contemporary production and construction references. At the same time, the work is configured in manual form as a reference for understanding and application with respect to traditional and complex façade systems. The study is aimed at researchers, designers and, in general, operators in the field of the advanced façade systems, considering that the level of composition of the work is directed at experts in the specific matter, who require a tool of a high explanatory and operational level. This is not a basic text, but a work that goes beyond the literature expressed on the subject at an architectural, descriptive or narrative level. The main topics concern the technological determination of lightweight prefabricated external curtain wall envelopes, according to the development of façade components, also considering multi-material relationships and specialized layering. The thematic in-depth study focuses on structural, connection and interface references related to the functional and application requirements articulated with respect to the main advanced curtain wall types. For each main type of façade, the work provides explanations and scientific information for investigating and designing the advanced façades according to the characteristics of the mullions and transoms façade system (stick system), of the structural sealant glazing façade system, of the unit façade system, of the suspended façade system and of the double skin façade system. The explanation is made with the aid of analytical insights into the physical, connective and interface constitution, supported by details and documents acquired from the advanced production and construction sectors. The book is envisaged to become the first work in a series of texts on the technical and scientific study of the advanced façade systems, planning to deal, in the future, with the contents related to the building site and construction phases, the specific constitution of the production methods, and an in-depth study of the enclosure and cladding materials. The book, intended as a basis for scientific, academy and professional study, is proposed as a useful tool within university courses, specialized and master’s courses, as well as a support for the preparation of expert technicians in the field of façade systems

Morphological and molecular identification of a strain of the unicellular green alga Dunaliella sp. isolated from Tarquinia Salterns

1 - Algae of the genus Dunaliella are among the most studied micro-algae. They are used for the production of feed, for nutritional reinforcement as a vitamin A precursor and for pharmaceuticals and fine chemicals. 2 - The current taxonomy of the genus is based on morphological and physiological attributes including the ability of some species to grow over wide salinity ranges and at extreme salinities, as well as the accumulation of high levels of â-carotene. The taxonomic status of the genus Dunaliella involves some uncertainty, moreover it is very difficult to compare results from different authors, owing to uncertainty on names and species. 3 - In this work, we compare morphological and molecular analysis to characterize a strain of Dunaliella isolated from Tarquinia salt ponds. Samples of natural populations of the unicellular green alga, were collected at various times during the study period to detail the vegetative motile cells and the different stages of its life cycle microscopically. The ITS1 and ITS2 regions were used for the molecular identification analysis. Conserved oligonucleotides of 18S rDNAs (MA3) and speciesspecific primers (DSs), designed from variable sequences, were used to corroborate the identification. 4 - Blast results indicated that our sequences matched at the 100% level with Dunaliella salina Teod reported in Gen Bank. Consequently, based on comparative cell morphology and molecular analysis, the new Dunaliella isolate from Tarquinia salt ponds was classified as D. salina

Measurement of angular momentum transport in turbulent flow between independently rotating cylinders

We present measurements of the angular momentum flux (torque) in Taylor-Couette flow of water between independently rotating cylinders for all regions of the \(\Omega_1, \Omega_2\) parameter space at high Reynolds numbers, where $\Omega_1$ \(\Omega_2\) is the inner (outer) cylinder angular velocity. We find that the Rossby number Ro = \(\Omega_1 - \Omega_2\)/\Omega_2 fully determines the state and torque $G$ as compared to G(Ro = \infty) \equiv \Gi. The ratio G/\Gi is a linear function of $Ro^{-1}$ in four sections of the parameter space. For flows with radially-increasing angular momentum, our measured torques greatly exceed those of previous experiments [Ji \textit{et al.}, Nature, \textbf{444}, 343 (2006)], but agree with the analysis of Richard and Zahn [Astron. Astrophys., \textbf{347}, 734 (1999)].Comment: 4 pages, 4 figures, to appear in Physical Review Letter

No more time to stay ‘single’ in the detection of Anisakis pegreffii, A. simplex (s. s.) and hybridization events between them: a multi-marker nuclear genotyping approach

A multi-marker nuclear genotyping approach was performed on larval and adult specimens of Anisakis spp. (N = 689) collected from fish and cetaceans in allopatric and sympatric areas of the two species Anisakis pegreffii and Anisakis simplex (s. s.), in order to: (1) identify specimens belonging to the parental taxa by using nuclear markers (allozymes loci) and sequence analysis of a new diagnostic nuclear DNA locus (i.e. partial sequence of the EF1 α−1 nDNA region) and (2) recognize hybrid categories. According to the Bayesian clustering algorithms, based on those markers, most of the individuals (N = 678) were identified as the parental species [i.e. A. pegreffii or A. simplex (s. s.)], whereas a smaller portion (N = 11) were recognized as F1 hybrids. Discordant results were obtained when using the polymerase chain reaction–restriction fragment length polymorphisms (PCR–RFLPs) of the internal transcribed spacer (ITS) ribosomal DNA (rDNA) on the same specimens, which indicated the occurrence of a large number of ‘hybrids’ both in sympatry and allopatry. These findings raise the question of possible misidentification of specimens belonging to the two parental Anisakis and their hybrid categories derived from the application of that single marker (i.e. PCR–RFLPs analysis of the ITS of rDNA). Finally, Bayesian clustering, using allozymes and EF1 α−1 nDNA markers, has demonstrated that hybridization between A. pegreffii and A. simplex (s. s.) is a contemporary phenomenon in sympatric areas, while no introgressive hybridization takes place between the two species

A parametric-assisted method for 3D generation of as-built BIM models for the built heritage

The paper outlines a parametric-assisted method for the 3D reconstruction and creation of BIM models for the built heritage. The research implements the emerging paradigms of open sourcing, cloud computing and interoperability, employing low-cost technologies (digital photogrammetry) and open source software (Grasshopper for Rhinoceros) which can ease the accessibility to a potential reuse of heritage, typically requiring high specialists and expensive equipment. The research examines the abandoned Albergo Diurno “Venezia” in Milan, heritage with a unique architectural value – a blend of Liberty and Art Deco styles. The process of 3D reconstruction of the ceiling is described. Custom algorithms have been developed to automatically rebuild the complex and irregular geometry from mesh, towards the creation of a NURBS-based 3D model. It is shown how the proposed methodology can streamline the process of data elaboration by reducing arbitrary operations and improve accuracy to preserve geometric irregularities. The associative model allows the automatic improvement in the model definition when more precise input data is feeding the algorithm, offering the opportunity to relate the precision of BIM models in accordance with the needed level of detail (LOD)