A numerical table of Lommel functions with two imaginary arguments

Numerical table of Lommel functions with two imaginary argument

A mini-array for large air showers

A mini-array that utilizes the Linsley effect is proposed for the measurement of large air showers. An estimate of the detectable shower rates for various shower sizes is made. Details of the detection and data collection systems are also described

The distribution and function of the ATP-sensitive potassium channel subunit Kir6.1 in cardiac and skeletal muscle cell lines.

ATP-sensitive potassium channels (KAtp) are present in the plasma membrane of a number of tissues but are also present on endomembranes such as the endoplasmic reticulum (ER) and mitochondria. They are involved in a number of physiological and pathophysiological processes and form a link between cellular metabolism and membrane excitability. Ischaemic preconditioning describes the phenomenon in which a short period of ischaemia protects against a more prolonged one. The ability of potassium channel openers such as pinacidil and nicorandil can mimic this phenomenon, with inhibitors such as glibenclamide to abolish this response, led to the suggestion that the final effector in this process was the sarcolemmal Katp channel as it was able to shorten the cardiac action potential reducing the energy requirements of the cell. However, a number of pharmacological observations were not compatible with this hypothesis as diazoxide, which does not activate the sarcolemmal channel, was able to mimic preconditioning. The focus of research then turned to the potential involvement of a KAtp channel present in the mitochondrial inner membrane called the mitoKArp channel. The molecular identification of this channel would be important and there is controversial evidence to suggest that Kiro.l may be a major component of the mitoKATP channel. I examined the hypothesis that the localisation of Kir6.1 is functionally significant in cardiac and skeletal muscle because it generates important K+ flux in intracellular membranes such as the ER and perhaps mitochondria. Co-localisation studies showed that transfected Kiro.l was located in the ER with a small but significant proportion in mitochondria. However, Kir6.1 was ER retained and not trafficked to the plasma membrane when co-expressed with its regulatory subunit, the sulphonylurea receptor SUR1. Immunofluorescent staining also detected the presence of endogenous Kir6.1 in these cell lines using antibodies specific to Kir6.1. The distribution of Kir6.1 suggests that it may play a role in reactive oxygen species (ROS) production, calcium (Ca) handling in the ER and perhaps cellular respiration in mitochondria. ROS production is often associated with KAtp channel opening and protection against cell death at reperfusion. My results showed that diazoxide induced ROS production in C2C12, HepG2 and HEK293 cell lines with glibenclamide abolishing this effect. However, in the absence of Kir6.1, the same response was still observed. This suggests that Kir6.1 is not involved in the mechanism that is responsible for ROS production. The functional role of KAtp channels were also examined in mitochondria by measuring flavoprotein and NADH autofluorescence, an index of mitochondrial redox state and mitochondrial membrane potential (Au/m) in C2C12 cells and rat ventricular myocytes. In myocytes, flavoprotein oxidation increased when cells were treated with 3-nitroproprionic acid (3-NPA) and diazoxide. Glibenclamide did not reverse this effect. However, this phenomenon was absent in C2C12 cells. Given these observations, 3-NPA and diazoxide did not affect the Avj/m in C2C12 cells whereas glibenclamide caused mitochondrial depolarisation. The Aij/m could not be measured in myocytes. A large proportion of Kir6.1 resides in the ER and I examined whether Kir6.1 would alter ATP-induced Ca2+ transients. Upon ATP stimulation, C2C12 cells released Ca2+ from internal stores via the P2Y purinergic signalling pathway. The use of dominant negatives (DN) for Kir6.1 showed that ATP-induced Ca2+ transients were affected by the absence of Kir6.1. However, on closer inspection it was revealed that the presence of eGFP to identify transfected cells seriously perturbed the Fura-2 signal. In conclusion, the KAtp sensitive channel subunit Kir6.1 is predominantly distributed in the ER with a small but significant proportion in mitochondria. I also report that pharmacological compounds such as diazoxide and glibenclamide are not always truly 'selective' for the activation and inhibition of KAtp channels. I have not identified a specific role for Kir6.1 but my data suggests that Kir6.1 is not part of the mitoKATp channel and Kir6.1 is not involved in ROS production and mitochondrial function but it may still have a role in Ca2+ handling

Structural balance emerges and explains performance in risky decision-making.

Polarization affects many forms of social organization. A key issue focuses on which affective relationships are prone to change and how their change relates to performance. In this study, we analyze a financial institutional over a two-year period that employed 66 day traders, focusing on links between changes in affective relations and trading performance. Traders' affective relations were inferred from their IMs (>2 million messages) and trading performance was measured from profit and loss statements (>1 million trades). Here, we find that triads of relationships, the building blocks of larger social structures, have a propensity towards affective balance, but one unbalanced configuration resists change. Further, balance is positively related to performance. Traders with balanced networks have the "hot hand", showing streaks of high performance. Research implications focus on how changes in polarization relate to performance and polarized states can depolarize

Stellar Populations in the Phoenix Dwarf (dIrr/dSph) Galaxy as Observed by HST/WFPC2

We present HST/WFPC2 photometry of the central regions of the Phoenix dwarf. Accurate photometry allows us to: 1) confirm the existence of the horizontal branch previously detected by ground-based observations, and use it to determine a distance to Phoenix, 2) clearly detect the existence of multiple ages in the stellar population of Phoenix, 3) determine a mean metallicity of the old red giant branch stars in Phoenix, and suggest that Phoenix has evolved chemically over its lifetime, 4) extract a rough star formation history for the central regions which suggests that Phoenix has been forming stars roughly continuously over its entire lifetime.Comment: Accepted by AJ, 22 pages including 6 figures + 1 figure in JPEG forma

Information and Particle Physics

Information measures for relativistic quantum spinors are constructed to satisfy various postulated properties such as normalisation invariance and positivity. Those measures are then used to motivate generalised Lagrangians meant to probe shorter distance physics within the maximum uncertainty framework. The modified evolution equations that follow are necessarily nonlinear and simultaneously violate Lorentz invariance, supporting previous heuristic arguments linking quantum nonlinearity with Lorentz violation. The nonlinear equations also break discrete symmetries. We discuss the implications of our results for physics in the neutrino sector and cosmology

The Ratio of Total to Selective Extinction Toward Baade's Window

We measure the ratio of total to selective extinction, R_{VI}=A_V/E(V-I), toward Baade's Window by comparing the VIK colors of 132 Baade's Window G and K giants from Tiede, Frogel, & Terndrup with the solar-neighborhood (V-I),(V-K) relation from Bessell & Brett. We find R_{VI}=2.283 +/- 0.016, and show that our measurement has no significant dependence on stellar type from G0 to K4. Adjusting the Paczynski et al. determination of the centroid of the dereddened Baade's Window clump for this revised value of $R_{VI}$, we find I_{0,RC}=14.43 and (V-I)_{0,RC}=1.058. This implies a distance to the Baade's Window clump of d_{BW} = 8.63 +/- 0.16 kpc, where the error bar takes account of statistical but not systematic uncertainties.Comment: 8 pages, 1 figure, submitted to Ap

Proximity fingerprint of s+- superconductivity

We suggest a straightforward and unambiguous test to identify possible opposite signs of superconducting order parameter in different bands proposed for iron-based superconductors (s+- state). We consider proximity effect in a weakly coupled sandwich composed of a s+- superconductor and thin layer of s-wave superconductor. In such system the s-wave order parameter is coupled differently with different s+- gaps and it typically aligns with one of these gaps. This forces the other s+- gap to be anti-aligned with the s-wave gap. In such situation the aligned band induces a peak in the s-wave density of states (DoS), while the anti-aligned band induces a dip. Observation of such contact-induced negative feature in the s-wave DoS would provide a definite proof for s+- superconductivity.Comment: 4 pages, one figur