(Table 1) Stratigraphic occurrence and fossil content of fossiliferous horizons in southern north Victoria Land

In contrast to the adjacent parts of the Transantarctic Mountains, the Mesozoic macrofossil record of north Victoria Land remains poorly documented. During the Ninth German Antarctic North Victoria Land Expedition (GANOVEX IX 2005/2006) twelve fossil sites in southern north Victoria Land were discovered and sampled. Fossils from the Triassic to Early Jurassic Section Peak Formation were collected from Archambault Ridge, Anderton Glacier, Skinner Ridge, Timber Peak, Vulcan Hills, Runaway Hills, Section Peak and Shafer Peak. These localities have yielded abundant fossil wood and compressions of horsetails, ferns, and seed ferns. In addition, several beetle elytra were found at Timber Peak. Fossil localities of the overlying Shafer Peak Formation and Exposure Hill-type deposits occur at Shafer Peak and in the Mount Carson area, and have yielded various trace fossils, permineralized wood, leaf compressions, and conchostracans. Two newly discovered fossil sites are associated with the late Early Jurassic Kirkpatrick lava flows. Upright-standing tree trunks have been recorded at Suture Bench, and highly fossiliferous sedimentary interbeds occur at the southwestern end of the Mesa Range. Of special interest is the exquisite fossil preservation at some of the sites. Compression fossils from Timber Peak and Shafer Peak contain well-preserved cuticles, which is very rare in the Antarctic. An Early Jurassic permineralized deposit at Mount Carson contains structurally preserved ferns. Furthermore, the arthropod fossils from sedimentary interbeds at the Mesa Range are preserved in minute detail, including antennae and limb spines of a blattid insect.

Estudio de la variación del contenido de humedad en el Pinus pinaster Ait. por medio de la técnica no destructiva del georradar / Assessment of the variation of the moisture content in the Pinus pinaster Ait using the non destructive gpr technique

La variación en el contenido de humedad (CH) tiene una influencia significativa tanto en las propiedades físico- químicas de la madera, como en sus propiedades electromagnéticas y por tanto afecta a las características de la propagación de las ondas. En concreto, en este trabajo se estudia la capacidad del georradar (GR) empleando una antena de 1.6GHz de frecuencia central para registrar las variaciones que se producen en la velocidad y en la amplitud de las ondas electromagnéticas cuando se propagan en unas viguetas de madera de Pinus pinaster Ait de uso estructural cuyo CH va disminuyendo. Se ha comprobado como cuando el CH descendía la velocidad de propagación y las amplitudes, tanto de la onda directa como de la reflejada aumentaba. Los altos factores de correlación encontrados demuestran que el GR es una técnica capaz de evaluar, de forma no destructiva, el CH de la madera de uso estructural. The moisture content variations in wood have a significant influence in wood?s physicochemical properties, as well as in its electromagnetic properties and to specific effects upon waves? characteristics. In particular, this paper focuses on the analysis of the Ground-penetrating Radar?s (GPR) using an antenna of 1.6 GHz central frequency capacity to register the velocity and the amplitude of the electromagnetic waves? variation during the drying process of Pinus pinaster Ait timber joists. The results showed that when timber MC descended, the propagation velocity and amplitude of both the direct and the reflected wave increased. The high correlation found between the variables studied demonstrates GPR efficiency and the innovative application of this technique as a non-destructive evaluation tool for timber structures, particularly when studying its moisture content.

Influence of road noise disturbances on black vulture nesting area: Case of "Cabeza de Hierro" state in Spanish Mediterranean Central Mountain

The real and potential road influence on soundscape is considered a relevant management aspect that can assess the negative effects of massive visitants on such sensitive species -that have been living for centuries in the area-. As a first approach to the study of human disturbances sound impact, acoustic engineering tools allow us to model noise pollution caused by the main road that crosses the state ?Cabeza de Hierro? (M-604). For these preliminary results we use the French method XPS 31-133, recommend at EU level. Noise emission levels in black vulture nesting area are analyzed to understand the influence of human activities on rural areas and road management on biodiversity conservation. This approach develops a useful tool to make compatible the public enjoyment of forest services such as recreation or landscape scenary, the conservation of biodiversity as well as a suitable social and economic activity level ?timber and firewood harvesting, industry?- at the region.

The flexibility matrix o timber composite beams with a discrete connection system

This work presents a method for the analysis of timber composite beams which considers the slip in the connection system, based on assembling the flexibility matrix of the whole structure. This method is based on one proposed by Tommola and Jutila (2001). This paper extends the method to the case of a gap between two pieces with an arbitrary location at the first connector, which notably broadens its practical application. The addition of the gap makes it possible to model a cracked zone in concrete topping, as well as the case in which forming produces the gap. The consideration of induced stresses due to changes in temperature and moisture content is also described, while the concept of equivalent eccentricity is generalized. This method has important advantages in connection with the current European Standard EN 1995-1-1: 2004, as it is able to deal with any type of load, variable section, discrete and non-regular connection systems, a gap between the two pieces, and variations in temperature and moisture content. Although it could be applied to any structural system, it is specially suited for the case of simple supported and continuous beams. Working examples are presented at the end, showing that the arrangement of the connection notably modifies shear force distribution. A first interpretation of the results is made on the basis of the strut and tie theory. The examples prove that the use of EC-5 is unsafe when, as a rule of thumb, the strut or compression field between the support and the first connector is at an angle with the axis of the beam of less than 60º.

Use of calculus of variations to determine the shape of hovering rotors of minimum power and its application to micro air vehicles

In this paper, calculus of variations and combined blade element and momentum theory (BEMT) are used to demonstrate that, in hover, when neither root nor tip losses are considered; the rotor, which minimizes the total power (MPR), generates an induced velocity that varies linearly along the blade span. The angle of attack of every blade element is constant and equal to its optimum value. The traditional ideal twist (ITR) and optimum (OR) rotors are revisited in the context of this variational framework. Two more optimum rotors are obtained considering root and tip losses, the ORL, and the MPRL. A comparison between these five rotors is presented and discussed. The MPR and MPRL present a remarkable saving of power for low values of both thrust coefficient and maximum aerodynamic efficiency. The result obtained can be exploited to improve the aerodynamic behaviour of rotary wing micro air vehicles (MAV). A comparison with experimental results obtained from the literature is presented.

Geographical cataloguing of earthen architecture in Soria, Spain

This paper discusses the most relevant earth construction techniques that have been employed in the province of Soria (Spain). The objectives of the research are, first, to locate and catalogue each building techniques with earth within the geographic regions and environmental units and their relation to physical and human environment. Then, the second aim is analyze these techniques and characterize them in terms of material, components and construction processes. Three types are studied: the construction of rammed-earth walls, adobe masonry and timber frame filled with adobe.

Consideration of tip speed limitations in preliminary analysis of minimum COE wind turbines

A relation between Cost Of Energy, COE, maximum allowed tip speed, and rated wind speed, is obtained for wind turbines with a given goal rated power. The wind regime is characterised by the corresponding parameters of the probability density function of wind speed. The non-dimensional characteristics of the rotor: number of blades, the blade radial distributions of local solidity, twist angle, and airfoil type, play the role of parameters in the mentioned relation. The COE is estimated using a cost model commonly used by the designers. This cost model requires basic design data such as the rotor radius and the ratio between the hub height and the rotor radius. Certain design options, DO, related to the technology of the power plant, tower and blades are also required as inputs. The function obtained for the COE can be explored to �nd those values of rotor radius that give rise to minimum cost of energy for a given wind regime as the tip speed limitation changes. The analysis reveals that iso-COE lines evolve parallel to iso-radius lines for large values of limit tip speed but that this is not the case for small values of the tip speed limits. It is concluded that, as the tip speed limit decreases, the optimum decision for keeping minimum COE values can be: a) reducing the rotor radius for places with high weibull scale parameter or b) increasing the rotor radius for places with low weibull scale parameter

The effect of moisture content on nondestructive probing measurements

When assessing existing timber structures it is not possible to obtain density as the ratio mass/volume, so nondestructive probing methods are used to predict density. As in other nondestructive techniques, moisture content influences measurements. The goal of this paper is to study the influence of timber moisture content on two nondestructive probing techniques (penetration resistance and pullout resistance). 25 large cross section specimens of laricio pine from Spain were measured. The moisture content ranged from 65.1% to 8.3%. Penetration depth decreases and screw withdrawal strength increases when moisture content decreases below the fiber saturation point. There are lineal tendencies in both techniques. No moisture content influence was found in measures above fiber saturation point.

The Assessment of Total Energy Expenditure During a 14-day 'In-Season' Period of Professional Rugby League Players Using the Doubly Labelled Water Method

Peer reviewed

Torsional rigidity of single actin filaments and actin–actin bond breaking force under torsion measured directly by in vitro micromanipulation

Knowledge of the elastic properties of actin filaments is crucial for considering its role in muscle contraction, cellular motile events, and formation of cell shape. The stiffness of actin filaments in the directions of stretching and bending has been determined. In this study, we have directly determined the torsional rigidity and breaking force of single actin filaments by measuring the rotational Brownian motion and tensile strength using optical tweezers and microneedles, respectively. Rotational angular fluctuations of filaments supplied the torsional rigidity as (8.0 ± 1.2) × 10−26 Nm2. This value is similar to that deduced from the longitudinal rigidity, assuming the actin filament to be a homogeneous rod. The breaking force of the actin–actin bond was measured while twisting a filament through various angles using microneedles. The breaking force decreased greatly under twist, e.g., from 600–320 pN when filaments were turned through 90°, independent of the rotational direction. Our results indicate that an actin filament exhibits comparable flexibility in the rotational and longitudinal directions, but breaks more easily under torsional load.

Twist grain boundaries in three-dimensional lamellar Turing structures

Steady spatial self-organization of three-dimensional chemical reaction-diffusion systems is discussed with the emphasis put on the possible defects that may alter the Turing patterns. It is shown that one of the stable defects of a three-dimensional lamellar Turing structure is a twist grain boundary embedding a Scherk minimal surface.

The mating-type and pathogenicity locus of the fungus Ustilago hordei spans a 500-kb region

The fungal pathogen Ustilago hordei causes the covered smut disease of barley and oats. Mating and pathogenicity in this fungus are controlled by the MAT locus, which contains two distinct gene complexes, a and b. In this study, we tagged the a and b regions with the recognition sequence for the restriction enzyme I-SceI and determined that the distance between the complexes is 500 kb in a MAT-1 strain and 430 kb in a MAT-2 strain. Characterization of the organization of the known genes within the a and b gene complexes provided evidence for nonhomology and sequence inversion between MAT-1 and MAT-2. Antibiotic-resistance markers also were used to tag the a gene complex in MAT-1 strains (phleomycin) and the b gene complex in MAT-2 strains (hygromycin). Crosses were performed with these strains and progeny resistant to both antibiotics were recovered at a very low frequency, suggesting that recombination is suppressed within the MAT region. Overall, the chromosome homologues carrying the MAT locus of U. hordei share features with primitive sex chromosomes, with the added twist that the MAT locus also controls pathogenicity.

Torsional directed walks, entropic elasticity, and DNA twist stiffness

DNA and other biopolymers differ from classical polymers because of their torsional stiffness. This property changes the statistical character of their conformations under tension from a classical random walk to a problem we call the “torsional directed walk.” Motivated by a recent experiment on single lambda-DNA molecules [Strick, T. R., Allemand, J.-F., Bensimon, D., Bensimon, A. & Croquette, V. (1996) Science 271, 1835–1837], we formulate the torsional directed walk problem and solve it analytically in the appropriate force regime. Our technique affords a direct physical determination of the microscopic twist stiffness C and twist-stretch coupling D relevant for DNA functionality. The theory quantitatively fits existing experimental data for relative extension as a function of overtwist over a wide range of applied force; fitting to the experimental data yields the numerical values C = 120 nm and D = 50 nm. Future experiments will refine these values. We also predict that the phenomenon of reduction of effective twist stiffness by bend fluctuations should be testable in future single-molecule experiments, and we give its analytic form.