Developing Bayesian-based Confidence Bounds for Non-identically Distributed Observations using the Lyapunov Condition

The purpose of this paper is to establish a direct method for assessing the confidence in the detection and identification probabilities for segmented observations that are not identically distributed across assigned segments within a region. This paper arrives at easily computable confidence intervals by showing through mathematical analysis that: I. The probability of successful detection within each test segment can be characterized by a Beta distribution; II. The distribution of a weighted sum of independent but non-identically distributed sample means is asymptotically Normally distributed by the Lyapunov variant of the Central Limit Theorem, i.e., the approximation improves as the number of samples increases; III. Given that the distribution of the sample means convergences to a Normal distribution, the confidence intervals about the observed sample means for both the detection and identification probabilities can be determined in closed form for multiple target types. The motivation for this approach is the need to determine the exceedance probabilities to support a Systems Acceptance Test based on collected data

Transport and Magnetic Studies of New Mixed-Valence Compounds: K3Cu8Se6, KCu3Se2, K3Cu8Te6 and BaCuS3-x

New mixed-valent copper chalcogenides BaCuS3_x and K3Cu8X6 with X = Se or Te and KCu3Se2, with chemical patterns corresponding to the recently investigated K3Cu8S6 and KCu3S2, were synthesized. For these new samples the results of resistivity and magnetic susceptibility measurements are presented. For BaCuS3_x, K3Cu8Se6 and KCu3Se2 the metal—insulator transition is observed with the low temperature phase being metallic, which is untypical, whereas K3Cu8Te6 is a metal in the investigated temperature range. The temperature dependence of magnetic susceptibility of the studied samples testifies to their diamagnetic or weakly paramagnetic behaviour

Study of ultrathin Pt/Co/Pt trilayers modified by nanosecond XUV pulses from laser-driven plasma source

We have studied the structural mechanisms responsible for the magnetic reorientation between in-plane and out-of-plane magnetization in the (25 nm Pt)/(3 and 10 nm Co)/(3 nm Pt) trilayer systems irradiated with nanosecond XUV pulses generated with laser-driven gas-puff target plasma source of a narrow continuous spectrum peaked at wavelength of 11 nm. The thickness of individual layers, their density, chemical composition and irradiation-induced lateral strain were deduced from symmetric and asymmetric X-ray diffraction (XRD) patterns, grazing-incidence X-ray reflectometry (GIXR), grazing incidence X-ray fluorescence (GIXRF), extended X-ray absorption fine structure (EXAFS) and transmission electron microscopy (TEM) measurements. In the as grown samples we found, that the Pt buffer layers are relaxed and that the layer interfaces are sharp. As a result of a quasi-uniform irradiation of the samples, the XRD, EXAFS, GIXR and GIXRF data reveal the formation of two distinct layers composed of Pt1-xCox alloys with different Co concentrations, dependent on the thickness of the as grown magnetic Co film but with similar ∼1% lateral tensile residual strain. For smaller exposure dose (lower number of accumulated pulses) only partial interdiffusion at the interfaces takes place with the formation of a tri-layer composed of Co-Pt alloy sandwiched between thinned Pt layers, as revealed by TEM. The structural modifications are accompanied by magnetization changes, evidenced by means of magneto-optical microscopy. The difference in magnetic properties of the irradiated samples can be related to their modification in Pt1-xCox alloy composition, as the other parameters (lateral strain and alloy thickness) remain almost unchanged. The out-of-plane magnetization observed for the sample with initially 3 nm Co layer can be due to a significant reduction of demagnetization factor resulting from a lower Co concentration

The impact of traditional management on seasonal internal parasite burdens and productivity of indigenous Tswana goats in southern Botswana

Data collected monthly over a period of two years were live weight, packed cell volume (PCV), nematode faecal egg counts (FECs) and coccidial oocyst counts from faecal analyses for 100 mixed age (3-7 years) indigenous Tswana does. The aims of this experiment were to determine seasonal FECs and coccidial oocysts in these goats and quantify the relationships of these burdens to liveweight and PCV. FECs significantly ( P<0.05) varied with season, with the warmer seasons viz spring, summer and autumn having higher log (x+1) parasite burdens than the cooler winter, while seasonal trends for coccidial oocysts were not obvious. PCV was also significantly ( P<0.05) lower in the warmer seasons than winter. FECs and coccidial oocysts in all seasons were less than the mean log (x+1) of 3.3 inferred to reduce production in small stock. Correlation coefficients were strongly negative: -0.95 for FECs and liveweight and -0.84 for FECS and PCV, indicating that these worms had a negative impact on productivity. A further study should be conducted to quantify the effects of controlling these parasites during the warm seasons on productivity.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat v.9 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.Botswana College of Agricultur

Damage accumulation in thin ruthenium films induced by repetitive exposure to femtosecond XUV pulses below the single shot ablation threshold

The process of damage accumulation in thin ruthenium films exposed to multiple femtosecond XUV free electron laser FEL pulses below the critical angle of reflectance at the Free electron LASer facility in Hamburg FLASH was experimentally analyzed. The multi shot damage threshold is found to be lower than single shot damage threshold. Detailed analysis of the damage morphology and its dependence on irradiation conditions justifies the assumption that cavitation induced by the FEL pulse is the prime mechanism responsible for multi shot damage in optical coating

Structural pathways for ultrafast melting of optically excited thin polycrystalline Palladium films

Due to its extremely short timescale, the non-equilibrium melting of metals is exceptionally difficult to probe experimentally. The knowledge of melting mechanisms is thus based mainly on the results of theoretical predictions. This work reports on the investigation of ultrafast melting of thin polycrystalline Pd films studied by optical laser pump - X-ray free-electron laser probe experiments and molecular-dynamics simulations. By acquiring X-ray diffraction snapshots with sub-picosecond resolution, we capture the sample's atomic structure during its transition from the crystalline to the liquid state. Bridging the timescales of experiments and simulations allows us to formulate a realistic microscopic picture of melting. We demonstrate that the existing models of strongly non-equilibrium melting, developed for systems with relatively weak electron-phonon coupling, remain valid even for ultrafast heating rates achieved in femtosecond laser-excited Pd. Furthermore, we highlight the role of pre-existing and transiently generated crystal defects in the transition to the liquid state.Comment: main manuscript 33 pages, 9 figures; supplemental material 19 pages, 13 figures - all in one fil

Characterization of megahertz X ray laser beams by multishot desorption imprints in PMMA

Proper diagnostics of intense free electron laser FEL X ray pulses is indisputably important for experimental data analysis as well as for the protection of beamline optical elements. New challenges for beam diagnostic methods are introduced by modern FEL facilities capable of delivering powerful pulses at megahertz MHz repetition rates. In this paper, we report the first characterization of a defocused MHz 13.5 nm beam generated by the free electron laser in Hamburg FLASH using the method of multi pulse desorption imprints in poly methyl methacrylate PMMA . The beam fluence profile is reconstructed in a novel and highly accurate way that takes into account the nonlinear response of material removal to total dose delivered by multiple pulses. The algorithm is applied to experimental data of single shot ablation imprints and multi shot desorption imprints at both low 10 Hz and high 1 MHz repetition rates. Reconstructed response functions show a great agreement with the theoretical desorption response function mode

Mechanism of single shot damage of Ru thin films irradiated by femtosecond extreme UV free electron laser

Ruthenium is a perspective material to be used for XUV mirrors at free electron laser facilities. Yet, it is still poorly studied in the context of ultrafast laser matter interaction. In this work, we present single shot damage studies of thin Ru films irradiated by femtosecond XUV free electron laser pulses at FLASH. Ex situ analysis of the damaged spots, performed by different types of microscopy, shows that the weakest detected damage is surface roughening. For higher fluences we observe ablation of Ru. Combined simulations using Monte Carlo code XCASCADE 3D and the two temperature model reveal that the damage mechanism is photomechanical spallation, similar to the case of irradiating the target with optical lasers. The analogy with the optical damage studies enables us to explain the observed damage morphologie

Experimental study of EUV mirror radiation damage resistance under long term free electron laser exposures below the single shot damage threshold

The durability of grazing and normal incidence optical coatings has been experimentally assessed under free electron laser irradiation at various numbers of pulses up to 16 million shots and various fluence levels below 10 of the single shot damage threshold. The experiment was performed at FLASH, the Free electron LASer in Hamburg, using 13.5 nm extreme UV EUV radiation with 100 fs pulse duration. Polycrystalline ruthenium and amorphous carbon 50 nm thin films on silicon substrates were tested at total external reflection angles of 20 and 10 grazing incidence, respectively. Mo Si periodical multilayer structures were tested in the Bragg reflection condition at 16 off normal angle of incidence. The exposed areas were analysed post mortem using differential contrast visible light microscopy, EUV reflectivity mapping and scanning X ray photoelectron spectroscopy. The analysis revealed that Ru and Mo Si coatings exposed to the highest dose and fluence level show a few per cent drop in their EUV reflectivity, which is explained by EUV induced oxidation of the surfac