Size of National Assemblies: The Classic Derivation of the Cube-Root Law is Conceptually Flawed

For half a century, the analysis of the size of national assemblies was dominated by the famous cube-root relation with the population. However, a revisitation of that historical work with a physicist’s approach reveals basic conceptual problems that fatally undermine its conclusions. Furthermore, the assembly size evaluation exceeds the accuracy of all power equations, which cannot be reliably used for political analysis.

Dynamic and energetic constraints on the modality and position of the intertropical convergence zone in an aquaplanet

<p>The tropical zonal-mean precipitation distribution can vary between single and double peaks, which are associated with intertropical convergence zones (ITCZs). Here, the meridional modality and the sensitivity to hemispherically-asymmetric heating of tropical precipitation is studied in an idealized GCM with parameterized wind-driven ocean energy transport (OET). In the idealized model, transitions from unimodal to bimodal distributions are driven by equatorial ocean upwelling and cooling which inhibits equatorial precipitation. For sufficiently strong cooling, the circulation bifurcates to anti-Hadley circulation (AHC) in the deep tropics, with a descending branch near the equator and off-equatorial double ITCZs. The intensity of the AHC is limited by a negative feedback: the AHC drives westerly surface winds which balance the easterly stress (and hence equatorial upwelling) required for its maintenance. The modality of the precipitation affects the response to asymmetric heating: For weak ocean stratification, OET damps shifts of the tropical precipitation centroid but amplifies shifts of precipitation peaks. For strong ocean stratification, which leads to double ITCZs, asymmetric heating leads to relative intensification of the ITCZ in the warming hemisphere, but the positions of the double ITCZs are insensitive to changes in the asymmetric heating and ocean stratification. The dynamic feedbacks of the coupled system damp the slope of the atmospheric energy transport (AET) near the equator. This justifies a cubic root relation between the cross-equatorial AET and the position of the ITCZ, which captures migrations of the ITCZ significantly better than the commonly-used linear relation.</p>

Integrable Matrix Product States from boundary integrability

We consider integrable Matrix Product States (MPS) in integrable spin chains and show that they correspond to “operator valued” solutions of the so-called twisted Boundary Yang-Baxter (or reflection) equation. We argue that the integrability condition is equivalent to a new linear intertwiner relation, which we call the “square root relation”, because it involves half of the steps of the reflection equation. It is then shown that the square root relation leads to the full Boundary Yang-Baxter equations. We provide explicit solutions in a number of cases characterized by special symmetries. These correspond to the “symmetric pairs” (SU(N),SO(N)) and (SO(N),SO(D)\otimes⊗SO(N-D)), where in each pair the first and second elements are the symmetry groups of the spin chain and the integrable state, respectively. These solutions can be considered as explicit representations of the corresponding twisted Yangians, that are new in a number of cases. Examples include certain concrete MPS relevant for the computation of one-point functions in defect AdS/CFT.

Biophysical insight into mechanisms of sonoporation

This study presents a unique approach to understanding the biophysical mechanisms of ultrasound-triggered cell membrane disruption (i.e., sonoporation). We report direct correlations between ultrasound-stimulated encapsulated microbubble oscillation physics and the resulting cellular membrane permeability by simultaneous microscopy of these two processes over their intrinsic physical timescales (microseconds for microbubble dynamics and seconds to minutes for local macromolecule uptake and cell membrane reorganization). We show that there exists a microbubble oscillation-induced shear-stress threshold, on the order of kilopascals, beyond which endothelial cellular membrane permeability increases. The shear-stress threshold exhibits an inverse square-root relation to the number of oscillation cycles and an approximately linear dependence on ultrasound frequency from 0.5 to 2 MHz. Further, via real-time 3D confocal microscopy measurements, our data provide evidence that a sonoporation event directly results in the immediate generation of membrane pores through both apical and basal cell membrane layers that reseal along their lateral area (resealing time of ∼<2 min). Finally, we demonstrate the potential for sonoporation to indirectly initiate prolonged, intercellular gaps between adjacent, confluent cells (∼>30–60 min). This real-time microscopic approach has provided insight into both the physical, cavitation-based mechanisms of sonoporation and the biophysical, cell-membrane–based mechanisms by which microbubble acoustic behaviors cause acute and sustained enhancement of cellular and vascular permeability.

Evaluation of Impacted Mandibular Third Molars by Panoramic Radiography

Objective. The study was to evaluate impacted mandibular third molars (IM3M) for their angulation, level of eruption, third molar space and relation of inferior alveolar canal with their roots. Methods. Total 988 IM3M were studied in 578 individuals of age 18 years and above, dividing them into three groups i.e. symptomatic, asymptomatic and radiographic only. Individuals were also divided according to age, sex and side of IM3M (right or left). Panoramic radiographs were obtained after written consent and traced. ℵ2-test was applied to check inter-group and intra-group significance. Result. Out of 578 individuals 307 (53.11%) were males and 271 (46.89%) females. Maximum number of IM3M were in 18-27 years age group (398 i.e. 68.89%). Out of 988 IM3M, 39.93% were vertically placed. 61.84% IM3M were found at level A. Class II (79.65%) was the most common relation for third molar space. Notching (12.55%) was most common true inferior alveolar canal and IM3M root relation whereas superimposed (41.80%) was most common false inferior alveolar canal and IM3M root relation. For all the criteria significant inter-group difference was found (considering P<.05) and intra-group difference was non significant. Conclusion and significance. Panoramic radiographs can be used as reliable investigation for evaluation of IM3M.

Corner Shaping by Barrel Finishing

Corner shaping is a necessary operation in manufacturing of most mechanical components. Edge radiusing is the principal way to reduce stress concentration in components like gear, crank shaft, ball bearing, to permit assembly and disassembly of parts, to avoid local damage and to reduce the possibility of hurting the operators. Often precise values of corner radius are specified in component design. Deterministic operations such as chipping, plastic deformation and non traditional ones such as electro discharge machining, abrasive jet deburring are well established technology. Yet, sometimes, it results not economic or even impossible to perform these operations due to the complicated part geometry, difficulty in part clamping and tool path, large number of parts to be produced. Barrel finishing is technique able to improve the roughness of parts of complicated shape by means of a soft mechanical action over the surface performed by abrasive media. The main features of this technology is that the parts do not need to be fixed. Radiusing is, in turn, a potential application area for barrel finishing which has been investigated in this paper. Experimental tests were conducted on finished specimens with sharp corners in order to achieve information about corner radius evolution as a function of the time for different set parameters. The radius values have been assessed by analyzing the acquired profiles with a proprietary fitting procedure. It has been found a square root relation between radius and working time and, by assessing the influence of single parameter, a radiusing model has been proposed.

COMPORTAMENTO DE GENÓTIPOS DE ALGODÃO HERBÁCEO EM FUNÇÃO DA SALINIDADE DO SOLO.

COMPORTAMENTO DE GENÓTIPOS DE ALGODÃO HERBÁCEO EM FUNÇÃO DA SALINIDADE DO SOLO. Sérgio Oliveira Pinto de QueirozDoutorando, Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola, Departamento de Água e Solos, Campinas, SP, CEP 13093.970,Cx. Postal 6011, tel.: (019) 3788 1029, fax: (019) 3788 1010.Leonardo Theodoro BüllProfessor Titular, D. Sc., Departamento de Recursos Naturais, Faculdade de Ciências Agronômicas, Universidade Estadual Paulista, Fazenda Experimental Lageado, Botucatu, SP, CEP 18603 970, Cx. Postal 237, telefax: (14)6802 7169. 1 RESUMO O objetivo do presente estudo foi avaliar algumas variáveis fisiológicas de cinco cultivares de algodão (Gossypium hirsutum, L.) expostos à condições salino-sódicas do solo e a influência específica do sódio sobre os cultivares ACALA 1, PRECOCE 1, IAC 19, IAC 20 e EPAMIG 4.O experimento foi conduzido em casa de vegetação, sendo utilizados vasos plásticos com 8,5 kg de terra, nos quais foi aplicado NaCl, em quantidades suficientes para aumentar o nível de condutividade elétrica de 0 para 8, 16 e 24 dS. m-1 a 25º C. Em cada vaso foram aplicados 150 mg kg-1 de fósforo, além de solução nutritiva contendo 30 mg kg-1 de N e 40 mg kg-1 de K aos 15, 30 e 45 dias e semanalmente os vasos receberam solução diluída de micronutrientes.Os parâmetros fisiológicos avaliados foram altura de plantas, produção de matéria seca, relação parte aérea/raiz, área foliar, teor de clorofila, potencial de água na folha, índice refratométrico e teor relativo de água nas folhas.Os resultados evidenciaram que a elevação na concentração de sódio na solução do solo, reduziu a altura das plantas, a produção de matéria seca e a área foliar de todos os cultivares de algodão. UNITERMOS: algodão, cultivares, salinidade, sódio, fisiologia. QUEIROZ, S.O.P., BÜLL, L.T. BEHAVIOR OF GENOTYPES OF HERBACEOUS COTTON IN FUNCTION OF THE SALINITY OF SOIL 2 ABSTRACT The objective of this research was to study some physiologic variables of five cotton cultivars (Gossypium hirsutum, L.) exposed to saline-sodic soil conditions and the specific influence of sodium on cultivars Acala 1, Precoce 1, IAC 19, IAC 20 and EPAMIG 4.The experiment was conductes at greenhouse. The soil air-dried (8.5 kg) was packed in plastic vase, in which NaCl was applied to reach different electric conductivity (8, 16 and 24 dS . m -1). In all vases were applied 150 mg.kg-1 of P, besides nutritious solution contends 30 mg.kg-1 of N and 40 mg.kg-1 of K (KCl) to the 15, 30 and 45 days. Also it was applied diluted micronutrient solution weekly.The evaluated physiologic variables were: height of plant, dry matter production, shoot/root relation, leaf area, chlorophyll content, water potential in leaf, refratometric index and relative water content in leaves.The results showed increase jon the concentration of sodium in the soil solution, reduction of the plants height, dry matter production and leaf area in all cotton cultivars. KEYWORDS: cotton, cultivars, salinity, sodium, physiology.

Multiplicity of Solar-Type Stars

A systematic search for binaries in a sample of 123 bright field stars of types F3-G2 IV or V is described. Combination of the results for 25 newly discovered spectroscopic binaries with those of 21 spectroscopic, 23 visual, and 25 common-proper-motion pairs previously known brings to 88 the total number of companions identified in the sample. The distribution of the 88 periods shows a single maximum; the median period is 14 years.The frequencies of singles: doubles: triples: quadruples are found to be 42: 46: 9: 2. Less than half of the stars are thus observed to be single. Estimates of the completeness of this search lead to a determination of the number of systems missed and to a determination of their secondary masses.Analysis of the secondary-mass distributions, observed and predicted from completeness estimates, indicates the existence of two types of binaries.For systems with periods less than about 100 years, the distribution of secondaries varies with the cube-root of the secondary mass. These systems must be the result of fission. Two-thirds of their primaries have companions of stellar mass. Extrapolation of the cube-root relation implies that the remaining one-third of the primaries have non-stellar secondaries, i.e., close companions whose masses are less than 0.07 solar masses.For systems with periods larger than roughly 100 years the distribution of secondaries follows that given by the van Rhijn function. They must be the result of condensations that contracted separately but are bound gravitationally. Roughly three-fourths of all primaries in the sample have such distant companions, all of which are likely to be themselves close fission-systems. Evidently single stars are rare among solar-type dwarfs.

Properties of Action Potentials from Insect Motor Nerve Fibres

1. The properties of nerve action potentials in small insect motor nerves were studied using extracellular recording electrodes. 2. A length of nerve was lifted out of solution and recordings were made with respect to the solution either from an intact nerve (triphasic recording) or from near a cut end of the nerve (monophasic recording). 3. In a cockroach nerve, the number of spontaneously active fibres was small enough that corresponding nerve fibres could be identified in each preparation by their action potential amplitude and their pattern of activity. Under controlled conditions, the absolute amplitudes of either monophasic or triphasic records were reproducible and could be used to calculate fibre diameter. The calculations were confirmed from histological sections of the nerve. 4. Conduction velocity varied approximately as the 0.78 power of fibre diameter in a cockroach nerve and as 0.7 power of fibre diameter in a locust nerve. These values are considerably larger than the square root relation predicted if membrane properties are independent of fibre diameter. 5. Membrane properties probably vary with fibre diameter since the action potential duration increases dramatically for fibres below 5 µ in diameter. 6. For the cockroach nerve systematic structural differences between fibres of different sizes are also seen with the electron microscope and the relation of these to the functional differences is considered.