Identification of a lineage of multipotent hematopoietic progenitors

All multipotent hematopoietic progenitors in C57BL-Thy-1.1 bone marrow are divided among three subpopulations of Thy-1.1^(lo) Sca-1^+ Lin^(-/lo) c-kit^+ cells: long-term reconstituting Mac-1^-CD4^-c-kit^+ cells and transiently reconstituting Mac-1^(lo)CD4^-or Mac-1^(lo) CD4^(lo) cells. This study shows that the same populations, with similar functional activities, exist in mice whose hematopoietic systems were reconstituted by hematopoietic stem cells after lethal irradiation. We demonstrate that these populations form a lineage of multipotent progenitors from long-term self-renewing stem cells to the most mature multipotent progenitor population. In reconstituted mice, Mac-1- CD4^-c-kit^+ cells gave rise to Mac-1^(lo)CD4^- cells, which gave rise to Mac-1^(lo)CD4^(lo) cells. Mac-1^- CD4^-c-kit^+ cells had long-term self-renewal potential, with each cell being capable of giving rise to more than 10^4 functionally similar Mac-1^-CD4^-c-kit^+ cells. At least half of Mac-1^(lo)CD4^- cells had transient self-renewal potential, detected in the spleen 7 days after reconstitution. Mac-1^(lo)CD4^(lo) cells did not have detectable self-renewal potential. The identification of a lineage of multipotent progenitors provides an important tool for identifying genes that regulate self-renewal and lineage commitment

The roots of "Western European societal evolution". A concept of Europe by Jenő Szűcs

Jenő Szűcs wrote his essay entitled Sketch on the three regions of Europe in the early 1980s in Hungary. During these years, a historically well-argued opinion emphasising a substantial difference between Central European and Eastern European societies was warmly received in various circles of the political opposition. In a wider European perspective Szűcs used the old “liberty topos” which claims that the history of Europe is no other than the fulfillment of liberty. In his Sketch, Szűcs does not only concentrate on questions concerning the Middle Ages in Western Europe. Yet it is this stream of thought which brought a new perspective to explaining European history. His picture of the Middle Ages represents well that there is a way to integrate all typical Western motifs of post-war self-definition into a single theory. Mainly, the “liberty motif”, as a sign of “Europeanism” – in the interpretation of Bibó’s concept, Anglo-saxon Marxists and Weber’s social theory –, developed from medieval concepts of state and society and from an analysis of economic and social structures. Szűcs’s historical aspect was a typical intellectual product of the 1980s: this was the time when a few Central European historians started to outline non-Marxist aspects of social theory and categories of modernisation theories, but concealing them with Marxist terminology

Modeling assignment and production planning for medium wheel loaders : medium bank robotic welders

This project focused on the modeling assignments and production planning for the medium wheel loaders for Caterpillar. The purpose behind this project was to study and evaluate in detail the possible modeling combinations to optimize the current resources on the medium wheel loaders in the robotic welding cell. Through time studies, changes in the modeling assignments, and a study of the flow of material through the robotic welders, several alternatives were determined. The project team used three deciding factors: robot utilization, labor utilization, and annual cost savings. Alternative one had the smallest decrease in robot utilization, the highest labor utilization under 85%, and the largest annual cost savings. Thus, the modeling assignment changes as well as the preparatory station changes resulting from alternative 1 are what the project team recommends for implementation

Effect of the near surface layer for the microseismic monitoring – 2D modelling

Microseismic monitoring is usually used to map hydraulic fracture or stress changes in the reservoir, which is stimulated (Maxwell et al. 2010, Duncan & Eisner 2010). Examining the wave traveling through the reservoir can provide many important information on medium properties (Grechka et al. 2011) and can be used either to assess the stimulated reservoir or improve microseismic imagining. Microseismic monitoring network can be deployed either on surface or in borehole. Noise level observed on the surface network is usually 10 times higher than one observed in the receivers placed in borehole but still the detection the microseismic events by the surface array is possible (Eisner et al. 2010). In this study, we present the results of the synthetic modeling to show qualitatively and quantitatively the influence of the near-surface layer and the effect of the attenuation in this layer for the assessment of the strength of the signal recorded by receivers placed on the surface or just below it. For the purpose of this research, authors performed 2D seismic modeling using Tesseral software. We performed several different models, each of them in two variants. First variant included the impact of the impedance contrast of the near surface layer; in the second variant we suppressed that effect. Layer composition in models differed both in number and their properties (velocity and quality factor). In each model, we used one type of source located in 3 different places. Monitoring array was vertical and constrained with 100 geophones. First receiver was placed on the surface, and the spacing between phones was 1m. Data obtained with this procedure were then analyzed using Matlab software. For each model, we compered the relative amplitudes of the different events in both variants, and then assessed the impact of the impedance contrast in the near surface layer. Performed modeling proved that the influence of the near surface layer is significant. We observe that the amplitude ratio between the first receivers in two variants of each model ranges from 1.5 to almost 2, regardless of the depth of the source. Signal enhancement is the function of the impedance contrast, and does not depend on the attenuation in the near surface layer. However, attenuation does not influence the enhancement of the signal, very low quality factor in the shallow layers highly influences the strength of the arriving waves

Comparison of solutions for microseismic focal mechanism estimation

One of the major advantages of microseismic data, recorded during hydraulic fracturing of prospective shale intervals is ability to use both P and S wave in the analysis, not only to determine epicentral locations of events but also to describe source itself. The information about the mechanisms of located microseismic events allows better understanding of in situ stress and strain conditions and the local subsurface geomechanical properties and forces (Kamei et al. 2015). As Duncan stated in his work, a proper characterization of the observed events mechanisms is the key to understand radiation pattern of the signals in the investigated area (Duncan & Eisner 2010). Moreover, an understanding of the nature of the rock failure supports reservoir simulation models and stimulated reservoir volume estimates (Kratz & Thorton 2016). Proper assessment of event strike, dip and rake provides the geometry of the fracture plane assuming double couple focal mechanism, while full moment tensor inversion provides information about shear and tensile nature of the calculated mechanisms. The common method to obtain reliable focal mechanisms of observed microseismic events is decomposing of the full moment tensor. Seismic moment tensor is powerful tool which provides a general mathematical solution of sources that can be used to distinguish between various types of microseismic events. The method comes to reliably estimation of the six independent components of a full moment tensor by lestsquares inversion (Eaton & Forouhideh 2010). The motivation for this analysis was to determine microseismic focal mechanisms based on P – wave peak amplitude, P and S – waves peak amplitudes and S – wave peak amplitude only to estimate the differences and uncertainties between these three different solutions. Furthermore authors decided to check how the mechanisms changes with different geometries of downhole monitoring array. In this study only synthetic data computed in MiVu GeoTomo software using raytracing method and simple layered velocity model were used. The mentioned velocity model was constructed based on well logs data delivered by PGNiG from measurements done in Northern Poland where active exploration of shale gas takes place. In this analysis authors focused only on double couple (DC) and compensated linear vector dipole (CLVD) mechanisms which are two most common types of microseismic focal mechanisms occur during hydraulic fracturing of shale deposits. Performed analysis proved that the best and most consistent results with the lowest uncertainties reflected in the condition number parameter can be obtained by using both P and S peak amplitudes