Planar ion trap (retarding potential analyzer) experiment for atmosphere explorer

The retarding potential analyzer and drift meter were carried aboard all three Atmosphere Explorer spacecraft. These instruments measure the total thermal ion concentration and temperature, the bulk thermal ion velocity vector and some limited properties of the relative abundance of H(+), He(+), O(+) and molecular ions. These instruments functioned with no internal failures on all the spacecraft. On AE-E there existed some evidence for external surface contamination that damaged the integrity of the RPA sweep grids. This led to some difficulties in data reduction and interpretation that did not prove to be a disastrous problem. The AE-D spacecraft functioned for only a few months before it re-entered. During this time the satellite suffered from a nutation about the spin axis of about + or - 2 deg. This 2 deg modulation was superimposed upon the ion drift meter horizontal ion arrival angle output requiring the employment of filtering techniques to retrieve the real data

Ion Drift Meter for Dynamics Explorer

The ion drift meter for Dynamics Explorer B is discussed. It measures two mutually perpendicular angles of arrival of thermal ions with respect to the sensor look directions. These angles lie in the vertical and horizontal planes and may be thought of as pitch and yaw in the conventional aerodynamic sense. The components of the ion drift velocity along vertical and horizontal axes through the spacecraft body are derived to first order from knowledge of the spacecraft velocity vector and more accurately with additional knowledge of the component of ion drift along the sensor look direction

Farm poultry houses

Good growth of poultry and heavy egg production depend to a large extent upon the proper housing of the stock. This bulletin sets forth the essentials of a good house for Iowa in brief form and then offers working plans of three houses that embody these essentials. The first consideration in building a poultry house is its location. It is of greatest importance to select a site having well-drained soil as will be explained later. It is next important to have a convenient location. The poultry house may be nearer the residence than the live stock barns and as women have a large share in the management of the flock on the average farm, it should be so located. It is undesirable to build the poultry house near granaries, cribs, or barns which may furnish a harbor for rats and other vermin which prey on poultry. A sunny location well sheltered from the north winds is highly desirable whenever it is possible to obtain it without sacrificing good ground drainage

Calibration of liquid argon and neon detectors with 83Krm^{83}Kr^m

We report results from tests of $^{83}$Kr$^{\mathrm{m}}$, as a calibration source in liquid argon and liquid neon. $^{83}$Kr$^{\mathrm{m}}$ atoms are produced in the decay of $^{83}$Rb, and a clear $^{83}$Kr$^{\mathrm{m}}$ scintillation peak at 41.5 keV appears in both liquids when filling our detector through a piece of zeolite coated with $^{83}$Rb. Based on this scintillation peak, we observe 6.0 photoelectrons/keV in liquid argon with a resolution of 6% ($\sigma$/E) and 3.0 photoelectrons/keV in liquid neon with a resolution of 19% ($\sigma$/E). The observed peak intensity subsequently decays with the $^{83}$Kr$^{\mathrm{m}}$ half-life after stopping the fill, and we find evidence that the spatial location of $^{83}$Kr$^{\mathrm{m}}$ atoms in the chamber can be resolved. $^{83}$Kr$^{\mathrm{m}}$ will be a useful calibration source for liquid argon and neon dark matter and solar neutrino detectors.Comment: 7 pages, 12 figure

Direct WIMP identification: Physics performance of a segmented noble-liquid target immersed in a Gd-doped water veto

We evaluate background rejection capabilities and physics performance of a detector composed of two diverse elements: a sensitive target (filled with one or two species of liquefied noble gasses) and an active veto (made of Gd-doped ultra-pure water). A GEANT4 simulation shows that for a direct WIMP search, this device can reduce the neutron background to O(1) event per year per tonne of material. Our calculation shows that an exposure of one tonne $\times$ year will suffice to exclude spin-independent WIMP-nucleon cross sections ranging from $10^{-9}$ pb to $10^{-10}$ pb.Comment: 17 pages, 5 figures. Version accepted for publication in JCA

Importance of molecular cell biology investigations in human medicine in the story of the Hutchinson-Gilford progeria syndrome

Ranged among laminopathies, Hutchinson–Gilford progeria syndrome is a syndrome that involves premature aging, leading usually to death at the age between 10 to 14 years predominatly due to a myocardial infarction or a stroke. In the lecture I shall overview the importance of molecular cell biology investigations that led to the discovery of the basic mechanism standing behind this rare syndrome. The genetic basis in most cases is a mutation at the nucleotide position 1824 of the lamin A gene. At this position, cytosine is substituted for thymine so that a cryptic splice site within the precursor mRNA for lamin A is generated. This results in a production of abnormal lamin A, termed progerin, its presence in cells having a deleterious dominant effect. Depending on the cell type and tissue, progerin induces a pleiotropy of defects that vary in different tissues. The present endeavour how to challenge this terrible disease will be also mentioned

Curvature-coupling dependence of membrane protein diffusion coefficients

We consider the lateral diffusion of a protein interacting with the curvature of the membrane. The interaction energy is minimized if the particle is at a membrane position with a certain curvature that agrees with the spontaneous curvature of the particle. We employ stochastic simulations that take into account both the thermal fluctuations of the membrane and the diffusive behavior of the particle. In this study we neglect the influence of the particle on the membrane dynamics, thus the membrane dynamics agrees with that of a freely fluctuating membrane. Overall, we find that this curvature-coupling substantially enhances the diffusion coefficient. We compare the ratio of the projected or measured diffusion coefficient and the free intramembrane diffusion coefficient, which is a parameter of the simulations, with analytical results that rely on several approximations. We find that the simulations always lead to a somewhat smaller diffusion coefficient than our analytical approach. A detailed study of the correlations of the forces acting on the particle indicates that the diffusing inclusion tries to follow favorable positions on the membrane, such that forces along the trajectory are on average smaller than they would be for random particle positions.Comment: 16 pages, 8 figure

Observation of the Dependence of Scintillation from Nuclear Recoils in Liquid Argon on Drift Field

We have exposed a dual-phase Liquid Argon Time Projection Chamber (LAr-TPC) to a low energy pulsed narrowband neutron beam, produced at the Notre Dame Institute for Structure and Nuclear Astrophysics to study the scintillation light yield of recoiling nuclei in a LAr-TPC. A liquid scintillation counter was arranged to detect and identify neutrons scattered in the LAr-TPC target and to select the energy of the recoiling nuclei. We report the observation of a significant dependence on drift field of liquid argon scintillation from nuclear recoils of 11 keV. This observation is important because, to date, estimates of the sensitivity of noble liquid TPC dark matter searches are based on the assumption that electric field has only a small effect on the light yield from nuclear recoils.Comment: v3 updated to reflect published version, including a set of plots for 49.9 keV dat