Studies on the Fc receptor bearing cells in a transplanted methylcholanthrene induced mouse fibrosarcoma.

The presence of Fc receptors on the surface of cell suspensions obtained from a transplanted isogeneic methylcholanthrene induced murine fibrosarcoma has been investigated by determining the capacity of such cells to form rosettes with antibody coated SRBC. These studies indicate that a large percentage of cells in the tumour had Fc receptors on their surface. The proportion of such cells was increased by reducing the number of cells transplanted, by administering cyclophosphamide to the host, and on occasions by the i.p. injection of C. parvum. It was largely unaffected by the route of tumour cell transplantation or by T cell depletion of the host before transplantation but appeared to decline in older (i.e. larger) tumours. Both phagocytic and non-phagocytic cells had Fc receptors on their surface. The phagocytic population appeared to be affected most by procedures which altered the overall percentage of Fc receptor bearing cells. The Fc receptor bearing tumour cells were separated from those devoid of Fc receptors on the basis of their adherent properties. Upon transplantation to isogeneic hosts both populations gave rise to tumours containing a high percentage of Fc receptor bearing cells. These studies suggest that many of the Fc receptor bearing cells in our tumour are probably infiltrating cells of host origin. Their significance in relation to tumour growth remains to be established

Cancellation of the collisional frequency shift in caesium fountain clocks

We have observed that the collisional frequency shift in primary caesium fountain clocks varies with the clock state population composition and, in particular, is zero for a given fraction of the |F = 4, mF = 0> atoms, depending on the initial cloud parameters. We present a theoretical model explaining our observations. The possibility of the collisional shift cancellation implies an improvement in the performance of caesium fountain standards and a simplification in their operation. Our results also have implications for test operation of fountains at multiple pi/2 pulse areas

Guiding of cold atoms by a red-detuned laser beam of moderate power

We report measurements on the guiding of cold $^{87}$Rb atoms from a magneto-optical trap by a continuous light beam over a vertical distance of 6.5 mm. For moderate laser power ($<$85 mW) we are able to capture around 40% of the cold atoms. Although the guide is red-detuned, the optical scattering rate at this detuning ($\approx$70 GHz) is acceptably low. For lower detuning ($<$30 GHz) a larger fraction was guided but radiation pressure starts to push the atoms upward, effectively lowering the acceleration due to gravity. The measured guided fraction agrees well with an analytical model.Comment: final version, 6 pages, incl. 6 figure

A quantum point contact for neutral atoms

We show that the conductance of neutral atoms through a tightly confining waveguide constriction is quantized in units of lambda_dB^2/pi, where lambda_dB is the de Broglie wavelength of the incident atoms. Such a constriction forms the atom analogue of an electron quantum point contact and is an example of quantum transport of neutral atoms in an aperiodic system. We present a practical constriction geometry that can be realized using a microfabricated magnetic waveguide, and discuss how a pair of such constrictions can be used to study the quantum statistics of weakly interacting gases in small traps.Comment: 5 pages with 3 figures. To appear in Phys. Rev. Let

Evaluating and Minimizing Distributed Cavity Phase Errors in Atomic Clocks

We perform 3D finite element calculations of the fields in microwave cavities and analyze the distributed cavity phase errors of atomic clocks that they produce. The fields of cylindrical cavities are treated as an azimuthal Fourier series. Each of the lowest components produces clock errors with unique characteristics that must be assessed to establish a clock's accuracy. We describe the errors and how to evaluate them. We prove that sharp structures in the cavity do not produce large frequency errors, even at moderately high powers, provided the atomic density varies slowly. We model the amplitude and phase imbalances of the feeds. For larger couplings, these can lead to increased phase errors. We show that phase imbalances produce a novel distributed cavity phase error that depends on the cavity detuning. We also design improved cavities by optimizing the geometry and tuning the mode spectrum so that there are negligible phase variations, allowing this source of systematic error to be dramatically reduced.Comment: To appear in Metrologi

Measuring the stability of fundamental constants with a network of clocks

The detection of variations of fundamental constants of the Standard Model would provide us with compelling evidence of new physics, and could lift the veil on the nature of dark matter and dark energy. In this work, we discuss how a network of atomic and molecular clocks can be used to look for such variations with unprecedented sensitivity over a wide range of time scales. This is precisely the goal of the recently launched QSNET project: A network of clocks for measuring the stability of fundamental constants. QSNET will include state-of-the-art atomic clocks, but will also develop next-generation molecular and highly charged ion clocks with enhanced sensitivity to variations of fundamental constants. We describe the technological and scientific aims of QSNET and evaluate its expected performance. We show that in the range of parameters probed by QSNET, either we will discover new physics, or we will impose new constraints on violations of fundamental symmetries and a range of theories beyond the Standard Model, including dark matter and dark energy models

The resource-based orientation in decision making process of public medical entities – the results of empirical research

Niniejszy artykuł skupia się na wykorzystaniu podejścia zasobowego w zarządzaniu organizacją publiczną na przykładzie publicznych podmiotów leczniczych. W pierwszej części przedstawiono rozważania teoretyczne będące podstawą prowadzonych badań. Druga część pracy prezentuje wyniki badań empirycznych – identyfikację orientacji strategicznej publicznych podmiotów leczniczych.Present article focuses on the use of resource-based view in the public organization management, setting out an example of public medical entities. The first part of the article shows theoretical basis for conducted research. The second part of the article presents the results of empirical research – the identification of strategic orientation of public medical entities

The decion-making process in public organizatinos – proposed research method

Due to the importance of decision-making for the success of public organizations, the following article focuses on proposing the research method for the subject in question. The first part of the paper contains theoretical considerations regarding making decisions in public organizations. The second part proposes a research method of decision-making called reconstruction of decision-making process.Ze względu na znaczenie procesu podejmowania decyzji dla sukcesu organizacji publicznych niniejszy artykuł skupia się na propozycji metody badawczej przedmiotowego procesu. W pierwszej części artykułu zawarto rozważania teoretyczne dotyczące decydowania w organizacjach publicznych. Druga część zawiera propozycję wykorzystania tzw. rekonstrukcji procesu decyzyjnego do analizy procesu podejmowania decyzji w organizacjach publicznych

The characteristic of the environment of public organizations

Jedną z istotnych determinant sukcesu organizacji publicznej jest otoczenie, w którym funkcjonuje. Współczesne otoczenie organizacji charakteryzuje się dużą turbulentnością, co zmusza menedżerów publicznych do poszukiwania nowych narzędzi i metod zarządzania. Ze względu na znaczenie otoczenia dla sukcesu organizacji niniejszy artykuł koncentruje się na charakterystyce otoczenia organizacji publicznych.One of the important determinants of the success of a public organization is the environment in which it operates. Nowadays, the environment of public organization could be characterized by a large turbulence. The turbulence of the environment forces public managers to search for new tools and methods of management. Because of the importance of the environment for the success of the organization, this article focuses on the characteristics of the environment of public organizations

The identification of strategic orientation of public medical entities in relation to volatility of their environment

W warunkach rosnącej turbulencji otoczenia organizacje publiczne zmuszone są do poszukiwania nowych strategii działania. Jedną z nich jest proponowane w literaturze wykorzystanie podejścia zasobowego. Artykuł przedstawia wyniki badań przeprowadzonych wśród publicznych podmiotów leczniczych, których celem było zidentyfikowanie orientacji strategicznej organizacji i odniesienie jej do zmienności otoczenia oraz efektywności. Otrzymane wyniki wskazują, że pomimo dominacji orientacji zasobowej nie przekłada się ona na wyższą efektywność organizacji.The volatility of the environment forces public organizations to look for new strategies. One of the proposed in the literature strategy is resourcebased strategy. The article presents the results of research conducted among public medical entities. The goal of conducted research was to identify the strategic orientation of the organizations and referred it to the volatility of their environment and efficiency. The results show that the dominance of the resource orientation does not translate into higher efficiency of the organization