The possible companions of young radio pulsars

We discuss the formation of pulsars with massive companions in eccentric orbits. We demonstrate that the probability for a non-recycled radio pulsar to have a white dwarf as a companion is comparable to that of having an old neutron star as a companion. Special emphasis is given to PSR B1820−11 and PSR B2303+46. Based on population synthesis calculations we argue that PSR B1820−11 and PSR B2303+46 could very well be accompanied by white dwarfs with mass ≳1.1 M_⊙. For PSR B1820−11, however, we cannot exclude the possibility that its companion is a main-sequence star with a mass between ∼0.7 M_⊙ and ∼5 M_⊙.     

The neighborhood council: Where ‘top-down’ engages with ‘bottom-up’

The paper examines the neighborhood council from the perspective of its contribution to town planning. Within the context of planning in Israel, two distinct models of neighborhood council and their relationship to the municipal planning administration in two different towns are considered. Their potential as a new arena of planning at the neighborhood level is evaluated, including the ability to mediate between ‘bottom-up’ and ‘top-down’ planning processes, and to offer a planning framework that combines local with professional knowledge.     

Numerical simulation of artificial ground freezing in a fluid-saturated rock mass with account for filtration and mechanical processes

This study is devoted to the numerical simulation of the artificial ground freezing process in a fluid-saturated rock mass of the potassium salt deposit. A coupled model of nonstationary thermal conductivity, filtration and thermo-poroelasticity, which takes into account dependence of the physical properties on temperature and pressure, is proposed on the basis of the accepted hypotheses. The considered area is a cylinder with a depth of 256 meters and diameter of 26.5 meters and includes 13 layers with different thermophysical and filtration properties. Numerical simulation was carried out by the finite-element method. It has been shown that substantial ice wall formation occurs non-uniformly along the layers. This can be connected with geometry of the freezing wells and with difference in physical properties. The average width of the ice wall in each layer was calculated. It was demonstrated that two toroidal convective cells induced by thermogravitational convection were created from the very beginning of the freezing process. The effect of the constant seepage flow on the ice wall formation was investigated. It was shown that the presence of the slow flow lead to the delay in ice wall closure. In case of the flow with a velocity of more than 30 mm per day, closure of the ice wall was not observed at all in the foreseeable time.     

Receiver function imaging in strongly laterally heterogeneous crust:Synthetic modeling of BOLIVAR data

We resolve a large (～20 km) discrepancy in Moho depth determined from PdS receiver functions (RFs) and from active source seismic profiling in the complex Caribbean-South American plate boundary zone in eastern Venezuela.As part of the BOLIVAR experiment 20 broadband stations were deployed along an active source profile to record teleseisms.Using the extremely heterogeneous crustal model obtained from active source data,we generated 2D finite-difference elastic wave synthetics and from them calculated recei...     

Sea Ice Dynamics Induced by External Stochastic Fluctuations

The influence of stochastic fluctuations in the atmosphere and in the ocean caused by different occasional phenomena (noises) on dynamic processes of sea ice growth with a mushy layer is studied. It is shown that atmospheric temperature variances substantially increase the sea ice thickness, whereas dispersion variations of turbulent flows in the ocean to a great extent decrease the ice content produced by false bottom evolution.     

Transiting exoplanets from the CoRoT space mission Resolving the nature of transit candidates for the LRa03 and SRa03 fields

CoRoT is a space telescope which aims at studying internal structure of stars and detecting extrasolar planets. We present here a list of transits detected in the light curves of stars observed by CoRoT in two fields in the anti-center direction: the LRa03 one observed during 148 days from 3 October 2009 to 1 March 2010 followed by the SRa03 one from the 5 March 2010 to the 29 March 2010 during 25 days. 5329 light curves for the LRa03 field and 4169 for the SRa03 field were analyzed by the detection team of CoRoT. Then some of the selected exoplanetary candidates have been followed up from the ground. In the LRa03 field, 19 exoplanet candidates have been found, 8?remain unsolved. No secured planet has been found yet. In the SRa03 field, there were 11 exoplanetary candidates among which 6 cases remain unsolved and 3 planets have been found: CoRoT-18b, CoRoT-19b, CoRoT-20b.     

Line-source multi-tracer test for assessing high groundwater velocity

Segmented line-source multi-tracer injection is suggested as an effective method for assessing groundwater velocities and flow directions in subsurfaces characterized by high water flux. Modifying the common techniques of injecting a tracer into a well became necessary after point-source natural and forced gradient tracer tests ended with no reliable information on the local groundwater flow. The tracer's line-source increases the likelihood of success of the test and could provide additional information regarding the lateral heterogeneity of the aquifer. In a field experiment conducted in the northwestern part on the Dead Sea coast, tracers were injected into an 8-m-long line injection system perpendicular to the assumed flow direction. The injection system was divided into four separate segments with four different tracers. An array of five boreholes located within a 10 × 10 m area downstream was used for monitoring the tracers' transport. Two dye tracers (uranine and Na naphthionate) were injected in a long pulse of several hours into two of the injection pipe segments. Two other tracers (Rhenium oxide and Gd-DTPA) were instantaneously injected into the other two segments. The tracers were detected 0.7 to 2.3 h after injection in four of the five observation wells, located 2.3 to 10 m away from the injection system. The groundwater velocity was determined to be ～80 to 170 m/d, based on the recoveries of the tracers. The groundwater flow direction was derived based on the arrival of the tracers and was found to be quite consistent with the apparent direction of the hydraulic gradient.     

Artificial neural network assisted Bayesian calibration of climate models

We demonstrate and validate a Bayesian approach to model calibration applicable to computationally expensive General Circulation Models (GCMs) that includes a posterior estimate of the intrinsic structural error of the model. Bayesian artificial neural networks (BANNs) are trained with output from a GCM and used as emulators of the full model to allow a computationally efficient Markov Chain Monte Carlo (MCMC) sampling of the posterior for the GCM parameters calibrated against seasonal climatologies of temperature, pressure, and humidity. We validate the methodology by calibrating to targets produced by a model run with added noise. We then demonstrate a calibration of five GCM parameters against an observational data set. The approach accounts for both parametric and structural uncertainties of the model as well as uncertainties associated with the observational calibration data. This enables the generation of statistically rigorous probabilistic forecasts for future climate states. All calibration experiments are performed with emulators trained using a maximum of one hundred model runs, in accord with typical resource restrictions imposed by computationally expensive models. We conclude by summarizing remaining issues to address in order to create a complete and validated operational methodology for objective calibration of computationally expensive models.     

A bulk theory of airflow over a mountain ridge allowing for a stable overlying atmosphere

A steady-state, one-dimensional, mesoscale, non-linear problem of the airflow over a mountain ridge is considered in the framework of the bulk theory in an attempt to develop a meteorological generalisation of the hydraulic problem formulated and solved previously by Houghton and Kasahara. In essence, only three modifications of their formulation are made in the present paper: (a) inversion strength is introduced and considered as an additional dependent variable; (b) the atmosphere above the flow is assumed to be stably stratified with a constant vertical potential temperature gradient; and (c) the condition requiring the flow to return to its initial state after descending and moving away from the ridge is removed.The problem is reduced to a transcendental algebraic equation, the solution of which describes all the possible types of flow, including a discontinuous one. A classification and meteorological criterion graphically presented in the form of a map is proposed for the realisation of each type of flow.If the ridge is higher than some threshold, a jump arises above the windward slope and propagates against the flow. As a result, the initial parameters change to new values for which a secondary steady-state solution exists. An iterative method has been developed to calculate these new initial parameters.The general features of the different types of flow, including those with a jump and secondary flows, are discussed. It is shown that if the ridge height exceeds some second threshold there are no solutions at all, which means that the flow is totally blocked. Concrete calculated examples are presented of all possible types of steady-state flows including secondary ones.It is shown that after introduction of these modifications, the hydraulic model of Houghton and Kasahara acquires more real meteorological meaning.     

Movement of lithospheric plates relative to subduction zones: Formation of marginal seas and active continental margins

Subduction zones with deep seismicity are believed to be associated with the descending branches of convective flows in the mantle and are subordinated to them. Therefore, the position of subduction zones can be considered as relatively fixed with respect to the steady-state system of convective flows. The lithospheric plate overhanging a subduction zone (as a rule of continental type) may:

1. (1) either move away from the subduction zone; or

2. (2) move onto it. In the first case extensional conditions originate behind the subduction zone and the new oceanic crust of back-arc basins forms. In the second case active Andean-type continental margins with thickening of the crust and lithosphere are observed.

Behind the majority of volcanic island-arcs, along the boundary with marginal-sea basins, independent shallow seismicity belts can be traced. They are parallel to the main seismicity belts coinciding with the Benioff zones. The seismicity belts frame island-arc microplates. Island-arc microplates are assumed to be a frame of reference to calculate relative movements of the consuming and overhanging plates. Using slip vector azimuths for shallow seismicity belts in the frontal parts of the Kurile, Japan, Izu-Bonin, Mariana and Tonga—Kermadec arcs, the position of the pole of rotation of the Pacific plate with respect to the western Pacific island-arc microplates was computed. Its coordinates are 66.1°N, 119.2°W. From the global closure of plate movements it has been determined that for the past 10 m.y. the Eurasian and Indian plates have been moving away from the Western Pacific island-arc system, both rotating clockwise, around poles at 31.1°N, 164.2°W and 1.3°S, 157.5°W, respectively. This provides for the opening of the back-arc basins. At the same time South America is moving onto the subduction zone at the rate of 4 cm/yr. Some “hot spots”, such as Hawaiian, Tibesti, and those of the South Atlantic, are moving relative to the island-arc system at a very low rate, viz. 0.5–0.7 cm/yr. Presumably, the western Pacific subduction zone and “hot spots” form a single frame of reference which can generally be used for the analysis of absolute motions.