Firm Ground Research Articles

Seismic retrofit of low‐rise steel buildings in Canada using rocking steel braced frames

SummaryThis article examines the use of rocking steel braced frames for the retrofit of existing seismically deficient steel building structures. Rocking is also used to achieve superior seismic performance to reduce repair costs and disruption time after earthquakes. The study focuses on low‐rise buildings for which re‐centring is solely provided by gravity loads rather than added post‐tensioning elements. Friction energy dissipative (ED) devices are used to control drifts. The system is applied to 2‐storey and 3‐storey structures located in 2 seismically active regions of Canada. Firm ground and soft soil conditions are considered. The seismic performance of the retrofit scheme is evaluated using nonlinear dynamic analysis and ASCE 41‐13. For all structures, rocking permits to achieve immediate occupancy performance under 2% in 50 years seismic hazard if the braces and their connections at the building's top storeys are strengthened to resist amplified forces due to higher mode response. Base shears are also increased due to higher modes. Impact at column bases upon rocking induces magnified column forces and vertical response in the gravity system. Friction ED is found more effective for drift control than systems with ring springs or bars yielding in tension. Drifts are sufficiently small to achieve position retention performance for most nonstructural components. Horizontal accelerations are generally lower than predicted from ASCE 41 for regular nonrocking structures. Vertical accelerations in the gravity framing directly connected to the rocking frame are however higher than those predicted for ordinary structures. Vertical ground motions have limited effect on frame response.

Nodal superconvergence of the local discontinuous Galerkin method for singularly perturbed problems

Abstract In this paper, a superconvergence of order ( ln N ∕ N ) 2 k + 1 for the numerical traces of the LDG approximation to a one dimensional singularly perturbed convection–diffusion–reaction problem is proved. The LDG method is applied on a Shishkin mesh with 2 N elements, and we use polynomials of degree at most k on each element. This result puts the numerical finding reported in Xie and Zhang (2007), Xie et al. (2009) on firm mathematical ground.

Musical Harmony in the Xunzi and the Lüshi Chunqiu: Different Implications of Musical Harmony Resulting from Their Dissimilar Approaches to the Concept of Resonance between Sound and Qi

This article discusses two interpretations of musical harmony around the 3rd century BCE based on the Xunzi 荀子 and the Lushi Chunqiu 呂氏春秋 (Annals of Mr. Lu), comparing the concepts of resonance between sound and qi 氣 in each interpretation. The Xunzi supports the moral influence of the sage kings’ music where ethical resonance between sound and bodily qi serves as firm ground for musical harmony begetting social harmony. In contrast, the Lushi Chunqiu advocates the idea of physical resonance between sound and cosmic qi whereby musical harmony acts as a contributor to cosmic harmony. In discussing resonance between sound and qi, the Xunzi restricts its scope to the human realm while the Lushi Chunqiu extends it more broadly to the cosmic realm, which indicates that humans foster cosmic harmony. This broader perspective is an adequate reflection of the germinating idea of a resonant correlation between the human and cosmic realms.

RESILIENCE V DISKURZU O NÁRODNÍ BEZPEČNOSTI

The concept of "resilience" has turned into a powerful principle and a discursive tool in the fields of national and international security. To illustrate the growth of "resilience" in strategic discourse of some of the most powerful actors of the North Atlantic area, the article is divided in two parts. The first part analyzes the national security discourse of two major powers in the region, namely Great Britain and the United States. Using the timeframe of 2010-2015, the prominence of resilience is traced in a set of strategic documents. The second part elevates the level of analysis to the two most relevant international organizations - NATO and the EU. The objective of this part is to discuss the remarkable surge of resilience discourse, which gained a firm ground throughout 2016. The paper, therefore, explores the appeal of resilience for states as well as for international organizations, without drawing a causal relation between the two. It also highlights how resilience has played a powerful role as a value and a principle, as well as a desired end state, against a backdrop of complex and hybrid threats to both national and international security.

The Promotion and Protection Human Rights under Vietnam’s Civil Law

This article analyzes and assesses Vietnam’s civil law for the promotion and protection human rights, the successes and limitations of their implementation in practice. The research findings show that over the past years, the Civil Code has laid a firm ground for remarkable successes in the promotion and protection human rights, especially, not only of Vietnamese but also foreigners living and working in Vietnam. The code is deemed compliant with international human rights conventions, laws and practices. In the Civil Code, however, there remain some certain limitations. For example a number of provisions of the current Civil Code fail to meet the human rights legislation or do not really create favourable conditions for the promotion and protection human rights in the economic and social domains. Our objective aims to outline the theoretical bases and analyze, assess regulations on human rights provided for in the Civil Code of Vietnam at present, thence proposing some solutions for improving legal regulations and contributing to ensure human rights in the legal system of Vietnam in general and in the Civil Code in particular.

Plantar Exteroceptive Inefficiency causes an asynergic use ofplantar and visual afferents for postural control: Best means of remediation.

IntroductionSome subjects have difficulty to integrate both visual and plantar inputs, showing at the same time a “postural blindness” and a Plantar Exteroceptive Inefficiency (PEI). The former corresponds to a better stability eyes closed (EC) than eyes open (EO), while the latter is defined as a better stability on foam than on firm ground. Clinical studies reported that a manipulation of either plantar or visual input could affect the weight of both cues in postural control, suggesting interdependence in their use. The purpose of the experiment is to characterize the PEI phenomenon better and see if such synergy can be objectified.MethodsWe recruited 48 subjects (25 ± 3.3 years) and assessed their balance with a force platform, EO, EC, at 40 or 200 cm, on firm ground, Dépron® foam, Dynachoc® foam, or on a 3 mm‐thick Anterior Bar AB®. We assessed their sensorial preferences through their PQ and RQ.ResultsThe main results are that there normally exists a synergy in the use of plantar and visual afferents, but only at 40 cm and in the absence of PEI.ConclusionsPlantar Exteroceptive Inefficiency interferes with the role of vision in postural control, its effects are distance specific, are better revealed by Dépron® foam and the AB® improves posture but does not solve visual‐podal asynergy. These results also have clinical interests as they indicate the best way in terms of distance and choice of foam to diagnostic PEI. Finally, they suggest restricting the use of the AB®, commonly employed. These findings can be useful for clinicians concerned with foot, eye, and posture.

The invertebrate trace fossil Labyrintichnus in the Late Triassic red beds of the Argana Basin (Western High Atlas Mountains, Morocco)

Labyrintichnus terrerensis Uchman and Álvaro, 2000, a cylindrical, intrastratal, passively filled trace fossil composed of irregular nets and branched galleries, so far known from Miocene marginal lacustrine clastic sediments, was found in Carnian alluvial-plain sediments of the Argana Basin, Morocco. This is the oldest occurrence of this rarely reported trace fossil. Associated tetrapod footprints and invertebrate trace fossils (Diplopodichnus, Scoyenia, Spongeliomorpha, Taenidium, cf. Helminthoidichnites, and others) point to the Scoyenia ichnofacies typical of inundated and desiccating sediments. Co-occurring current-ripples, mudcracks and raindrop imprints confirm this interpretation. The trace fossils reflect changing consistency from softground (cf. Helminthoidichnites; Diplopodichnus) to firm ground (e.g., Spongeliomorpha). Beside beetles and their larvae, fly larvae are considered as possible tracemakers of shallow Labyrintichnus terrerensis on the basis of similarities to recent burrows.

Euclidean bridge to the relativistic constituent quark model

${\bf Background}$ Knowledge of nucleon structure is today ever more of a precision science, with heightened theoretical and experimental activity expected in coming years. At the same time, a persistent gap lingers between theoretical approaches grounded in Euclidean methods (e.g., lattice QCD, Dyson-Schwinger Equations [DSEs]) as opposed to traditional Minkowski field theories (such as light-front constituent quark models). ${\bf Purpose}$ Seeking to bridge these complementary worldviews, we explore the potential of a Euclidean constituent quark model (ECQM). This formalism enables us to study the gluonic dressing of the quark-level axial-vector vertex, which we undertake as a test of the framework. ${\bf Method}$ To access its indispensable elements with a minimum of inessential detail, we develop our ECQM using the simplified quark $+$ scalar diquark picture of the nucleon. We construct a hyperspherical formalism involving polynomial expansions of diquark propagators to marry our ECQM with the results of Bethe-Salpeter Equation (BSE) analyses, and constrain model parameters by fitting electromagnetic form factor data. ${\bf Results}$ From this formalism, we define and compute a new quantity --- the Euclidean density function (EDF) --- an object that characterizes the nucleon's various charge distributions as functions of the quark's Euclidean momentum. Applying this technology and incorporating information from BSE analyses, we find the dressing effect on the proton's axial-singlet charge to be small in magnitude and consistent with zero. ${\bf Conclusions}$ The scalar quark $+$ diquark ECQM is a step toward a realistic quark model in Euclidean space, and urges additional refinements. The small size we obtain for the impact of the dressed vertex on the axial-singlet charge suggests that models without this effect are on firm ground to neglect it.

Divided differences in noncommutative geometry: Rearrangement Lemma, functional calculus and expansional formula

We state a generalization of the Connes–Tretkoff–Moscovici Rearrangement Lemma and give a surprisingly simple (almost trivial) proof of it. Secondly, we put on a firm ground the multivariable functional calculus used implicitly in the Rearrangement Lemma and elsewhere in the recent modular curvature paper by Connes and Moscovici [3]. Furthermore, we show that the fantastic formulas connecting the one and two variable modular functions of loc. cit. are just examples of the plenty recursion formulas which can be derived from the calculus of divided differences. We show that the functions derived from the main integral occurring in the Rearrangement Lemma can be expressed in terms of divided differences of the Logarithm, generalizing the “modified Logarithm” of Connes–Tretkoff [4]. Finally, we show that several expansion formulas related to the Magnus expansion [13] have a conceptual explanation in terms of a multivariable functional calculus applied to divided differences.

Pietro Daniel Omodeo (Editor). Duncan Liddel (1561–1613): Networks of Polymathy and the Northern European Renaissance. With Karin Friedrich. (Scientific and Learned Cultures and Their Institutions, 17.) xii + 322 pp., figs., bibl., index. Leiden/Boston: Brill, 2016. €135 (cloth).

Pietro Daniel Omodeo (Editor). <i>Duncan Liddel (1561–1613): Networks of Polymathy and the Northern European Renaissance</i>. With Karin Friedrich. (Scientific and Learned Cultures and Their Institutions, 17.) xii + 322 pp., figs., bibl., index. Leiden/Boston: Brill, 2016. €135 (cloth).

Cavalcanti en el París errante

París fue por mucho tiempo la gran metrópoli moderna. En los años veinte del siglo pasado también fue el centro de las vanguardias artísticas e intelectuales. Por sus calles deambularon, entre otros, Walter Benjamin, Baudelaire y Gyula Halász (Brassaï), quienes encontraron en el placer de vagar por la ciudad una experiencia y una forma de exploración estética, que también descubrió en su momento el movimiento dadá. En ese placer, tal vez sin saberlo, continuaron con una tradición que ya había iniciado Gérald de Nerval en el siglo XIX en lo que él denominó “promenade nocturne”. Pues bien, esta misma idea se percibe en el filme Rien que les heures (1926) de Alberto Cavalcanti. Allí se muestran, desde la perspectiva del inmigrante, dos ciudades que se contraponen, pero que necesariamente son indisociables, pues las dos son inevitablemente París. Por un lado, se encuentra la moderna y glamorosa París que se asienta sobre suelo firme, a la arivière del Sena, como paisaje perfecto para los boulevards, las grandes avenidas y les cafés en donde aún departían dandies acompañados de hermosas mesdemoiselles. Pero, por el otro, se muestra otra que convivía al margen y donde aún vagaban los hoy desaparecidos chiffonniers o el encantador flâneur, a quien también le cantó Baudelaire. Estos personajes, junto con prostituées, bandits et marins, entre muchos otros, habitaban estas calles que conformaban un mundo en el que vivían, vagaban, luchaban, se enamoraban y morían, tal vez bajo la mirada impávida de la metrópoli normalizada, pero siempre condescendiente o, si se quiere, alcahueta de la otra ciudad que aquí denomino: el París errante.

Nonempirical Calculation of Superconducting Transition Temperatures in Light-Element Superconductors.

Recent progress in the fully nonempirical calculation of the superconducting transition temperature (Tc ) is reviewed. Especially, this study focuses on three representative light-element high-Tc superconductors, i.e., elemental Li, sulfur hydrides, and alkali-doped fullerides. Here, it is discussed how crucial it is to develop the beyond Migdal-Eliashberg (ME) methods. For Li, a scheme of superconducting density functional theory for the plasmon mechanism is formulated and it is found that Tc is dramatically enhanced by considering the frequency dependence of the screened Coulomb interaction. For sulfur hydrides, it is essential to go beyond not only the static approximation for the screened Coulomb interaction, but also the constant density-of-states approximation for electrons, the harmonic approximation for phonons, and the Migdal approximation for the electron-phonon vertex, all of which have been employed in the standard ME calculation. It is also shown that the feedback effect in the self-consistent calculation of the self-energy and the zero point motion considerably affect the calculation of Tc . For alkali-doped fullerides, the interplay between electron-phonon coupling and electron correlations becomes more nontrivial. It has been demonstrated that the combination of density functional theory and dynamical mean field theory with the ab initio downfolding scheme for electron-phonon coupled systems works successfully. This study not only reproduces the experimental phase diagram but also obtains a unified view of the high-Tc superconductivity and the Mott-Hubbard transition in the fullerides. The results for these high-Tc superconductors will provide a firm ground for future materials design of new superconductors.

Effects of gait training on sand on improving the walking ability of patients with chronic stroke: a randomized controlled trial

[Purpose] This study examines how difference in sandy ground between firm ground influences the effects of gait training in patients with chronic stroke. [Subjects and Methods] A total of 28 patients with chronic stroke were evenly divided into experimental and control groups. Initial evaluation of the subjects was conducted by Timed Up & Go (TUG) and 6-Minute Walking Test (6MWT). Each patient in both groups received daily, 30-minute gait training on sandy ground and firm ground, five times each week, for a total of six weeks, after which reevaluation was conducted. [Results] In TUG, both groups showed significant improvement after the intervention. In 6MWT, only the experimental group achieved significantly increased distance after the intervention. However, there was no between-group difference. Improvement in dynamic balancing ability depends on repeated gait training rather than differences in the ground environment. However, gait endurance showed a difference depending on the types of ground, regardless of repeated gait training. [Conclusion] This can be attributed to the fact that gait training on sand requires use of more diverse muscles. Hence, we can confirm the potential of sand as a new material for training ground when attempting to improve walking ability, particularly gait endurance, among patients with chronic stroke.

Suspension of Phenomenological Judgement of Scientific Naivety

The article addresses the negative judgements on natural sciences, however persistent and frequent they may be, found scattered in the philosophical texts of the two founding fathers of phenomenology, Edmund Husserl and Martin Heidegger. It first presents these harsh views and then, by assuming the phenomenological method, advocated by both philosophers, endeavours to suspend these judgements in favour of a phenomenologically more adequate description of the scientific comportment, trying to do justice to its non-philosophical excellence. The basic claim of the treatise is that Husserl's and Heidegger's criticisms should only be understood in the defensive sense of procuring a firm and safe ground for theoretical comportment, 'bios theoretikos'. Such an approach, however, begs for a phenomenological description of the intrinsic excellence of science, which might be phenomenologically most accurately understood as most rigorous practical comportment, as 'bios praktikos'.

Different soccer stud configurations effect on running and cutting movements

The purpose of this study was to test for differences in performance and injury risks between three different outsole configuration soccer shoes on natural turf. A total of 14 experienced soccer players participated in the tests. Participants were asked to complete tasks of straight-ahead running and 45° left sidestep cutting respectively at the speed of 5.0±0.2 m/s on natural turf. They selected soccer shoes with firm ground design (FG), artificial ground design (AG) and turf cleats (TF) randomly. During 45° cut, FG showed significantly smaller peak knee flexion and greater abduction angles than TF. FG showed significant greater peak horizontal ground reaction force (GRF) and average required traction ratio compared with AG and TF. FG may offer a performance benefit on artificial turf compared to AG and TF on natural turf. However, increased knee valgus angle and decreased knee flexion angle of FG may increase knee loading and risk of anterior cruciate ligament (ACL) injury. Higher vertical average loading rate and excessive plantar pressure of FG may also resulted in calluses observed in plantar skin, forefoot pain or even metatarsal stress fracture. In summary, FG would enhance athletic performance on natural turf, but also may undertake higher risks of non-contact injuries compared with AG and TF.

Early growth of camu-camu plants with nitrogen fertili- zation through fertirrigation

The objective of this study was to evaluate the effect of different doses of nitrogen (N), applied via fertirrigation, on the initial growth components of the camu-camu plants. It was conducted with the use of a randomized block experimental design with 5 treatments: 0; 40; 80; 120 and 160 kg ha-1 of N, eight replicates and seven plants per experimental parcel. The experiment lasted for a period of 270 days. The diameter of stem (mm) and the height of the plant (cm) were evaluated every 30 days and the number of branches and total length of branches (cm) were evaluated every 90 days. At the end of the experiment, chlorophyll a index, dry mass of the leaves (g), dry mass of the branches (g), dry mass of the roots (g), total dry mass (g), and the Dickson Quality Index (DQI) were evaluated. According to the results, camu-camu plants that did not receive nitrogen fertilization had a lower initial growth and the doses of N significantly influenced all parameters evaluated in the camu-camu plants, including parameters from a linear and a quadratic model. The dose of 123 kg ha-1 of N, applied via fertirrigation, produced better quality camu-camu plants. Furthermore, greater doses caused depressive effects on growth of camu-camu plants in the first year of cultivation in firm ground conditions and the indirect measurement of chlorophyll a index in camu-camu plants was suitable for the assessment of nutritional status in relation to N.

Caracterización de la geomorfología costera y sus coberturas vegetales asociadas, a través de sensores remotos en la bahía de Buenaventura, Valle del Cauca

La presente investigación comprendida entre La Bocana y Punta Limones, en el municipio de Buenaventura (Valle del Cauca), describe las características geomorfológicas y de cobertura vegetal a lo largo de 95.61 km de la costa Pacífica de Colombia, utilizando el sensoramiento remoto a través de la técnica de Light Detection and Ranging–LiDAR aerotransportada e imágenes satelitales y de sus productos. Geomorfológicamente, el territorio está repartido casi que equitativamente entre planicies costeras y colinas, siendo un poco mayor el área de las planicies costeras con un 53.06 % del área total estudiada (5637.56 ha), que a su vez se constituyen por planos y llanuras con vegetación halófita, planos de inundación, plataformas intermareales no vegetadas, y en menor proporción de lagunas costeras y playas. Sobre las dos primeras geoformas predomina el manglar y sobre la última predominan las herbáceas de playa. Las colinas y lomas (46.93 %) también se hacen presentes con los bosques densos altos de tierra firme y los helechales no inundables. En general, para el área de estudio, la cobertura vegetal que más abunda es el bosque denso alto de tierra firme con un 44.94 % (3690.47 ha), seguido por el manglar con 37.65 % (3092.54 ha). La idea de relacionar las características geomorfológicas con las coberturas vegetales surge de la necesidad de contar con herramientas geográficas para el ordenamiento y manejo de la costa Pacífica.

Local amplification and subsoil structure at a difficult site: Understanding site effects from different measurements

We present a detailed site effects study at a site (TYF) close to the Thermaikos gulf coast in Thessaloniki, northern Greece. Different types of data recorded by different instruments are analyzed. Empirical amplification is estimated using spectral ratios relative to a reference station (SSR) and horizontal to vertical spectral ratios (HVSR) using earthquake data. In addition, seismic noise records from different arrays were analyzed using HVSR. Our results show that earthquake data SSR fails for our data. The reason is the poor signal to noise ratio of our records. Better results were obtained using HVSR for earthquake data. Seismic noise HVSR were not useful due to the particular soil profile at TYF, with the exception of HVSR of seismic noise recorded in one of our arrays that were able to reflect a significant change in the coast line at our site. Although amplification at site TYF is relatively small, it is large enough to originate a difference of one intensity unit relative to firm ground motion. Amplification at TYF is caused by a deep soil structure (over 350m in depth) and therefore cannot be captured using measures like Vs30.

The influence of different soccer cleat type on kinetic, kinematic and neuromuscular ankle variables in artificial turf

Lateral ankle sprain is the most prevalent injury in soccer athletes. Enhanced by the variety of soccer cleats and by increased use of artificial turf, the interaction between the ground and the footwear has taken high importance as a lateral ankle sprain risk factor. The higher incidence of injuries in the second half of the match reflects the need of studying this interaction during tasks involving muscle fatigue. To evaluate the influence of different soccer cleats on kinetic, kinematic and neuromuscular ankle variables in artificial turf under two conditions: with and without fatigue of lateral ankle dynamic stabilizers. Study design: Experimental study within-subjects design. Twenty-four healthy athletes participated in this study. All subjects performed three sets of five medial-lateral unipodal jumps, each one with one of three models of cleats (Turf, Hard and Firm ground) on two conditions: with and without fatigue induced by the isokinetic dynamometer. The electromyographic activity of long and short peroneal heads, ground reaction forces and the movement of the rear-foot were collected and used to calculate kinematic (ankle eversion/inversion, centre of pressure displacement and velocity), kinetic (loading rate of the ground reaction forces) and neuromuscular variables (activation time of peroneal muscles). With the exception of decreased peroneal activation time with the Hard ground model (without fatigue vs. with fatigue), no statistically significant differences were identified in the ankle variables, between cleats, neither between the two evaluated conditions. In healthy soccer athletes, the contributor variables for ankle sprain were not influenced by the kind of soccer cleat in a functional test on a third generation artificial turf.

The motion aftereffect as a universal phenomenon in sensory systems involved in spatial orientation. III. Aftereffect of motion adaptation in the somatosensory and vestibular systems

The motion aftereffect may be considered as a consequence of visual illusions of self-motion (vection) and the persistence of sensory information processing. There is ample experimental evidence indicating a uniformity of mechanisms that underlie motion aftereffects in different modalities based on the principle of motion detectors. Currently, there is firm ground to believe that the motion aftereffect is intrinsic to all sensory systems involved in spatial orientation, that motion adaptation in one sensory system elicits changes in another one, and that such adaptation is of great adaptive importance for spatial orientation and motion of an organism. This review seeks to substantiate these ideas.