Analysis of Extended Partial Least Squares for Monitoring Large-Scale Processes

This paper theoretically analysis the recently proposed "Extended Partial Least Squares" (EPLS) algorithm. After pointing out some conceptual deficiencies, a revised algorithm is introduced that covers the middle ground between Partial Least Squares and Principal Component Analysis. It maximises a covariance criterion between a cause and an effect variable set (partial least squares) and allows a complete reconstruction of the recorded data (principal component analysis). The new and conceptually simpler EPLS algorithm has successfully been applied in detecting and diagnosing various fault conditions, where the original EPLS algorithm did only offer fault detection.

CaII K interstellar observations towards early-type disc and halo stars

We present high-resolution (R = lambda/Deltalambda similar to 40 000) Ca II K interstellar observations (lambda(air) = 3933.66Angstrom) towards 88 mainly B-type stars, of which 74 are taken from the Edinburgh-Cape or Palomar-Green surveys, and 81 have > 25degrees. The majority of the data come from previously existing spectroscopy, although also included are 18 new observations of stars with echelle spectra taken with UVES on the Very Large Telescope UT2 (Kueyen). Some 49 of the sample stars have distance estimates above the Galactic plane (z) greater than or equal to 1 kpc, and are thus good probes of the halo interstellar medium. Of the 362 interstellar Ca K components that we detect, 75 (21 per cent) have absolute values of their LSR velocity values exceeding 40 km s(-1). In terms of the deviation velocity for the sightlines with distance estimates, 46/273 (17 per cent) of components have velocity values exceeding those predicted by standard Galactic rotation by more than 40 km s(-1). Combining this data set with previous observations, we find that the median value of the reduced equivalent width (REW) of stars with z greater than or equal to 1 kpc (EW x sin ) is similar to 115 mAngstrom (n = 80), similar to that observed in extragalactic sightlines by Bowen. Using data of all z distances, the REW at infinity is found to be similar to 130 mAngstrom, with the scaleheight (1) of the Ca II K column density distribution being;z 800 pc (n = 196) and reduced column density at infinity of log[N(Ca II K) cm(-2)] similar to 12.24. This implies that similar to30 per cent of Ca II K absorption occurs at distances exceeding similar to1 kpc. For nine sightlines, with distance exceeding 1 kpc and with a companion object within 5degrees, we find that all but two have values of Ca II reduced equivalent width the same to within similar to20 per cent, when the REW of the nearest object is extrapolated to the distance of the further of the pair, and assuming 1 = 800 pc. For 29 of our sightlines with z greater than or equal to 1 kpc and a H I detection from the Leiden-Dwingeloo survey (beamsize of 0.5degrees), we find log(N(Ca II K)IN(H I)) ranging from -7.4 to - 8.4. Values of the Ca II K abundance relative to neutral hydrogen (log[N(Ca II K) cm(-2)] - log[N(H I) cm(-2)]) are found to be more than similar to0.5 dex higher in stars with distances exceeding approximate to100 pc, when compared with the (log[N(Ca II K) cm(-2)] -log[N(H-tot) cm(-2)]) values found in nearby sightlines such as those in Wakker & Mathis (2000). Finally, stellar Ca II K equivalent widths of the sample are determined for 26 objects.

Power-law behaviour, heterogeneity, and trend chasing

Long-range dependence in volatility is one of the most prominent examples in financial market research involving universal power laws. Its characterization has recently spurred attempts to provide some explanations of the underlying mechanism. This paper contributes to this recent line of research by analyzing a simple market fraction asset pricing model with two types of traders---fundamentalists who trade on the price deviation from estimated fundamental value and trend followers whose conditional mean and variance of the trend are updated through a geometric learning process. Our analysis shows that agent heterogeneity, risk-adjusted trend chasing through the geometric learning process, and the interplay of noisy fundamental and demand processes and the underlying deterministic dynamics can be the source of power-law distributed fluctuations. In particular, the noisy demand plays an important role in the generation of insignificant autocorrelations (ACs) on returns, while the significant decaying AC patterns of the absolute returns and squared returns are more influenced by the noisy fundamental process. A statistical analysis based on Monte Carlo simulations is conducted to characterize the decay rate. Realistic estimates of the power-law decay indices and the (FI)GARCH parameters are presented.

Are gatekeepers to renal services referring patients equitably?

Objective: Patients with chronic kidney disease (CKD) benefit from specialist interventions to retard progression of renal failure and prevent cardiovascular events. Certain patient groups have poor access to specialist renal services when dialysis is required. This study used a population-based laboratory database to investigate access to and timeliness of referral to renal specialists relatively early in the course of the disease.

Methods: All tests for serum creatinine and haemoglobin (Hb) A1c in Northern Ireland in a two-year period (2001 and 2002) were retrieved for 345,441 adults. Of these, 16,856 patients had at least one serum creatinine level above 150 µmol/L in 2001 not deemed to be due to acute renal failure (crude prevalence 1.42%). This cohort was followed until the end of 2002 and the differences in the time to referral to a specialist were assessed using Cox's proportional hazards regression.

Results: Diabetic patients, older patients and those living in deprived areas were significantly more likely to have serum creatinine testing, compared with non-diabetic, younger and those living in more affluent areas. Delays in referral to renal specialists for patients with raised serum creatinine levels were significantly shorter among diabetic patients, women, younger individuals, those living in rural areas, those living close to renal centres and those living in deprived areas. Overall, only 19% of diabetic patients and 6% of non-diabetic patients who had CKD had seen a renal specialist within 12 months of their index creatinine test.

Conclusion: Contrary to other diseases, disadvantaged patients do not seem to be under-investigated for renal disease compared with their more affluent neighbours and are generally referred earlier for specialist assessment. However, the absolute rate of timely specialist assessment is low. Recent changes in referral criteria for CKD will result in more referrals and will have serious resource implications. Opportunities for health gain among patients with declining renal function are being missed, particularly among the old and those living furthest from specialist centres.

Absolute single and multiple charge exchange cross sections for highly charged C, O, and Ne ions on H2O, CO, and CO2

Reported herein are measured absolute single, double, and triple charge exchange (CE) cross sections for the highly charged ions (HCIs) Cq+ (q=5,6), Oq+ (q=6,7,8), and Neq+ (q=7,8) colliding with the molecular species H2O, CO, and CO2. Present data can be applied to interpreting observations of x-ray emissions from comets as they interact with the solar wind. As such, the ion impact energies of 7.0q keV (1.62–3.06 keV/amu) are representative of the fast solar wind, and data at 1.5q keV for O6+ (0.56 keV/amu) on CO and CO2 and 3.5q keV for O5+ (1.09 keV/amu) on CO provide checks of the energy dependence of the cross sections at intermediate and typical slow solar wind velocities. The HCIs are generated within a 14 GHz electron cyclotron resonance ion source. Absolute CE measurements are made using a retarding potential energy analyzer, with measurement of the target gas cell pressure and incident and final ion currents. Trends in the cross sections are discussed in light of the classical overbarrier model (OBM), extended OBM, and with recent results of the classical trajectory Monte Carlo theory.

Densities and Derived Thermodynamic Properties of Imidazolium-, Pyridinium-, Pyrrolidinium-, and Piperidinium-Based Ionic Liquids

In the present work, experimental density measurements are reported along with the derived thermodynamic properties, such as the isothermal compressibility (?T), the isobaric expansivity (ap), and the thermal pressure coefficient (?v) for imidazolium-, pyridinium-, pyrrolidinium-, and piperidinium-based ionic liquids (ILs), namely, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate [C2mim][CF3SO3], 3-methyl-1-propylpyridinium bis(trifluoromethylsulfonyl)imide [C3mpy][NTf2], 1-methyl-1-propylpyrrolidinium bis(trifluoromethylsulfonyl)imide [C3mpyr][NTf2], 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide [C4mpyr][NTf2], and 1-methyl-1-propylpiperidinium bis(trifluoromethylsulfonyl)imide [C3mpip][NTf2] in the pressure (0.10 <P/MPa <35.00) and temperature (293.15 <T/K <393.15) domains. These ILs were chosen to provide an understanding of the influence of the cation and anion on the properties under study. Experimental densities are correlated with the Tait equation with an average absolute relative deviation (AARD) better than 0.02 %. It is shown that experimental densities are in good agreement with the densities obtained by the predictive method previously proposed by us.