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-

Construction of the Façade Systems. Production and Assembly Procedures 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 productive and constructive contents. The work is determined in the form of a knowledge and design concept tool for the construction of advanced façade systems, used for the realization of multiple types of envelope. The book is configured in a cognitive and operative form, with the aim of providing researchers, technicians and professionals with the contents to proceed with the analysis, design and constitution of façade systems with the aid of the components, materials and assembly methods typical of the advanced and experimental contemporary scenario. Moreover, the work goes into detail on how to form, connect and plan for the construction of the advanced façade systems, specifying itself as a manual text to provide guidelines for professionals in charge of design, production and construction. The work involves the building characters of the envelopes with respect to both the range series (determined by the basic profiles) and the customized or “outside system” components. The scenario under consideration accommodates, in the range series, the types of envelopes transferred by complex, large-scale interventions, with the inclusion of appropriate tools and accessories aimed at widespread use: therefore, the components are proposed in the form of “integrated” elements, characterized by “specialization” processes. Then, the contemporary experimental production observes the application of the archetypal and tectonic properties of envelope systems and the hybridization of established façade typologies through the use of profiles and frames of different material, mechanical and connective invoice. The study deals with the main building elements and technical interfaces, explaining the anchoring structures and their connections to the load-bearing structures, examining the criteria for the assembly between the mullion and transom profiles. The study of the façade systems focuses on the methods of collecting and draining rainwater, considering the execution of the sealing and the criteria of vapour pressure compensation and drainage for glass enclosures. The analysis of framing is completed with an explanation of the methods of mechanical and structural fastening of the enclosures, noting the criteria for pressure and structural silicone assembly. In particular, the text examines the technical interfaces of the main advanced envelope systems with respect to the functional, constructive and applicative coordination procedures of the mullions and transoms framing, 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 technical and manual character of the book is also expressed through the analysis of the functional and application procedures of the gaskets with respect to the façade systems in order to prevent the transmission of air and water loads: the analysis focuses on the connections between the framing and the enclosure elements of the envelope, in accordance with the compensation of height differences in order to guarantee impermeability, airtightness and insulation. The study observes and investigates the types of framing elements in which the gaskets are inserted, emphasizing the specific function with respect to the connection interfaces. Then, the study examines the assembly and interface conditions between elements of different composition and production within the façade systems: in particular, the examination of the technical interfaces involves the development and application of sealants, based on the loads exerted on the jointing devices, in order to fulfil the requirements of sealing and tightness with respect to mechanical, thermal and hygrometric, water, air and wind stresses. Moreover, the study of the envelope systems examines the methodologies directed towards fulfilling the requirements with respect to the actions caused by fire loads, considering the contents related to both components and connections and fixing surfaces. The design study involves the specific sections of separation with respect to the fire compartments: this is to limit the propagation of a fire originating inside the building, the fire of a façade and its propagation, the fall of the façade elements

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