Precision-recall operating characteristic (P-ROC) curves in imprecise environments

Traditionally, machine learning algorithms have been evaluated in applications where assumptions can be reliably made about class priors and/or misclassification costs. In this paper, we consider the case of imprecise environments, where little may be known about these factors and they may well vary significantly when the system is applied. Specifically, the use of precision-recall analysis is investigated and compared to the more well known performance measures such as error-rate and the receiver operating characteristic (ROC). We argue that while ROC analysis is invariant to variations in class priors, this invariance in fact hides an important factor of the evaluation in imprecise environments. Therefore, we develop a generalised precision-recall analysis methodology in which variation due to prior class probabilities is incorporated into a multi-way analysis of variance (ANOVA). The increased sensitivity and reliability of this approach is demonstrated in a remote sensing application.

Enhancement of photosynthetic carbon assimilation efficiency by phytoplankton in the future coastal ocean

A mesocosm experiment was conducted to evaluate the effects of future climate conditions on photosynthesis and productivity of coastal phytoplankton. Natural phytoplankton assemblages were incubated in field mesocosms under the ambient condition (present condition: ca. 400 ppmv CO2 and ambient temp.), and two future climate conditions (acidification condition: ca. 900 ppmv CO2 and ambient temp.; greenhouse condition: ca. 900 ppmv CO2 and 3 °C warmer than ambient). Photosynthetic parameters of steady-state light responses curves (LCs; measured by PAM fluorometer) and photosynthesis-irradiance curves (P-I curves; estimated by in situ incorporation of 14C) were compared to three conditions during the experiment period. Under acidification, electron transport efficiency (alpha LC) and photosynthetic 14C assimilation efficiency (alpha) were 10% higher than those of the present condition, but maximum rates of relative electron transport (rETRm,LC) and photosynthetic 14C assimilation (PBmax) were lower than the present condition by about 19% and 7%, respectively. In addition, rETRm,LC and alpha LC were not significantly different between and greenhouse conditions, but PBmax and alpha of greenhouse conditions were higher than those of the present condition by about 9% and 30%, respectively. In particular, the greenhouse condition has drastically higher PBmax and alpha than the present condition more than 60% during the post-bloom period. According to these results, two future ocean conditions have major positive effects on the photosynthesis in terms of energy utilization efficiency for organic carbon fixation through the inorganic carbon assimilation. Despite phytoplankton taking an advantage on photosynthesis, primary production of phytoplankton was not stimulated by future conditions. In particular, biomass of phytoplankton was depressed under both acidification and greenhouse conditions after the the pre-bloom period, and more research is required to suggest that some factors such as grazing activity could be important for regulating phytoplankton bloom in the future ocean.

Seawater carbonate chemistry and community calcification during Reunion Island coral reef community study, 2007

To assess the contribution of soft-bottoms to the carbon cycle in coral reefs, the net community production (p) was measured in winter at 3 stations on La Saline inner reef flat (Reunion Island). Changes in pH and total alkalinity at different irradiances (I) were assessed using benthic chambers (0.2 m2) during a 1-h incubation. Mean grain size, the silt and clay load and chlorophyll a content of the sediments were analysed in each chamber. Daily community production (P), gross community production (Pg) and community respiration (R) were estimated from p-I curves and daily irradiance variations (PAR, 400-700 nm). Sediment characteristics and chlorophyll a contents did not differ between the three sites, except for the silt and clay fraction at one station. R being higher than Pg (84.88 ± 7.36 and -62.29 ± 3.34 mmolC m-2 d-1 respectively), P value reached 22.59 ± 5.66 mmolC m-2 d-1. The sediments were therefore heterotrophic with a mean Pg/R lower than 1 (0.74 ± 0.05) and appear to be a carbon source. Our data suggested the importance of the degradation process in the functioning of near-reef sediments.

I. A study of the dynamics of triplet excitons in molecular crystals. II. An investigation of delayed light emission from Chlorella pyrenoidosa

I. PREAMBLE AND SCOPE

Brief introductory remarks, together with a definition of the scope of the material discussed in the thesis, are given.

II. A STUDY OF THE DYNAMICS OF TRIPLET EXCITONS IN MOLECULAR CRYSTALS

Phosphorescence spectra of pure crystalline naphthalene at room temperature and at 77˚ K are presented. The lifetime of the lowest triplet ³B_1u state of the crystal is determined from measurements of the time-dependence of the phosphorescence decay after termination of the excitation light. The fact that this lifetime is considerably shorter in the pure crystal at room temperature than in isotopic mixed crystals at 4.2˚ K is discussed, with special importance being attached to the mobility of triplet excitons in the pure crystal.

Excitation spectra of the delayed fluorescence and phosphorescence from crystalline naphthalene and anthracene are also presented. The equation governing the time- and spatial-dependence of the triplet exciton concentration in the crystal is discussed, along with several approximate equations obtained from the general equation under certain simplifying assumptions. The influence of triplet exciton diffusion on the observed excitation spectra and the possibility of using the latter to investigate the former is also considered. Calculations of the delayed fluorescence and phosphorescence excitation spectra of crystalline naphthalene are described.

A search for absorption of additional light quanta by triplet excitons in naphthalene and anthracene crystals failed to produce any evidence for the phenomenon. This apparent absence of triplet-triplet absorption in pure crystals is attributed to a low steady-state triplet concentration, due to processes like triplet-triplet annihilation, resulting in an absorption too weak to be detected with the apparatus used in the experiments. A comparison of triplet-triplet absorption by naphthalene in a glass at 77˚ K with that by naphthalene-h₈ in naphthalene-d₈ at 4.2˚ K is given. A broad absorption in the isotopic mixed crystal triplet-triplet spectrum has been tentatively interpreted in terms of coupling between the guest ³B_1u state and the conduction band and charge-transfer states of the host crystal.

III. AN INVESTIGATION OF DELAYED LIGHT EMISSION FROM Chlorella Pyrenoidosa

An apparatus capable of measuring emission lifetimes in the range 5 X 10^-9 sec to 6 X 10^-3 sec is described in detail. A cw argon ion laser beam, interrupted periodically by means of an electro-optic shutter, serves as the excitation source. Rapid sampling techniques coupled with signal averaging and digital data acquisition comprise the sensitive detection and readout portion of the apparatus. The capabilities of the equipment are adequately demonstrated by the results of a determination of the fluorescence lifetime of 5, 6, 11, 12-tetraphenyl-naphthacene in benzene solution at room temperature. Details of numerical methods used in the final data reduction are also described.

The results of preliminary measurements of delayed light emission from Chlorella Pyrenoidosa in the range 10^-3 sec to 1 sec are presented. Effects on the emission of an inhibitor and of variations in the excitation light intensity have been investigated. Kinetic analysis of the emission decay curves obtained under these various experimental conditions indicate that in the millisecond-to-second time interval the decay is adequately described by the sum of two first-order decay processes. The values of the time constants of these processes appear to be sensitive both to added inhibitor and to excitation light intensity.

Polnoe sobranīe sochinenīĭ I͡A.P. Polonskago.

Vol. 2 lacks special t.p.

Konstruktioner i interaktion. : de e som resurs i samtal

This study concerns the most common word pair in spoken Swedish, de e (it is, third person pronoun + copula-verb in present tense). The aim of the study is twofold, with an empirical aim and a theoretical aim. The empirical aim is to investigate if and how the string de e can be understood and described as a construction in its own right with characteristics that distinguishes it from other structures and resources in spoken Swedish. The theoretical aim is to test how two different linguistic theories and methods, interactional linguistics and construction grammar, can be combined and used to describe and explain patterns in languaging that traditional grammar does take into account. The empirical analysis is done within the interactional linguistic framework with sequence analyses of excerpts from authentic conversation data. The data consists of approximately ten hours of recorded conversation from Finland and Sweden. The sequence analysis suggests that the string de e really is used as a resource in its own right. In most cases, the string is also used in ways consistent with abstract grammatical patterns described by traditional grammar. Nevertheless, there are instances where de e is used in ways not described before: with numerals and infinitive phrases as complements, without any complements at all and together with certain complements (bra, de) in idiomatic ways. Furthermore, in the instances where de e is used according to known grammatical patterns the function of the particular string de e is clearly contextually specific and in various ways linked to the micro-context in which it is used. A new model is suggested for understanding and concluding the results from the sequence analyses. It consists of two different types of constructions grammatical and interactional. The grammatical constructions show how the string is used in eleven structurally different ways. The interactional constructions show seven different sequential positions and functions in which the string occurs. The two types of constructions are also linked to each other as potentials. This is a new way to describe how interactants use and responds to a concrete string like de e in conversation.

Plastic deformation in Ce-based bulk metallic glasses during depth-sensing indentation

The deformation behavior and the effect of the loading rate on the plastic deformation features in (numbers indicate at.%) Ce60Al15Cu10Ni15, Ce65Al10Cu10Ni10Nb5, Ce68Al10Cu20Nb2, and Ce70Al10Cu20 bulk metallic glasses (BMGs) were investigated through nanoindentation. The load-displacement (P-h) curves of Ce65Al10Cu10Ni10Nb5, Ce68Al10Cu2, and Ce70Al10Cu20 BMGs exhibited a continuous plastic deformation at all studied loading rate. Whereas, the P-h curves of Ce60Al15Cu10Ni15 BMG showed a quite unique feature, i.e. homogeneous plastic deformation at low loading rates, and a distinct serrated flow at high strain rates. Moreover, a creep deformation during the load holding segment was observed for the four Ce-based BMGs at room temperature. The mechanism for the appearance of the "anomalous" plastic deformation behavior in the Ce-based BMGs was discussed. (c) 2006 Elsevier B.V. All rights reserved.

Physical characterization of the rack effect and hydrogen bond networks in blue copper proteins

A summary of previous research is presented that indicates that the purpose of a blue copper protein's fold and hydrogen bond network, aka, the rack effect, enforce a copper(II) geometry around the copper(I) ion in the metal site. In several blue copper proteins, the C-terminal histidine ligand becomes protonated and detaches from the copper in the reduced forms. Mutants of amicyanin from Paracoccus denitrificans were made to alter the hydrogen bond network and quantify the rack effect by pK_a shifts.

The pK_a's of mutant amicyanins have been measured by pH-dependent electrochemistry. P94F and P94A mutations loosen the Northern loop, allowing the reduced copper to adopt a relaxed conformation: the ability to relax drives the reduction potentials up. The measured potentials are 265 (wild type), 380 (P94A), and 415 (P94F) mV vs. NHE. The measured pK_a's are 7.0 (wild type), 6.3 (P94A), and 5.0 (P94F). The additional hydrogen bond to the thiolate in the mutants is indicated by a red-shift in the blue copper absorption and an increase in the parallel hyperfine splitting in the EPR spectrum. This hydrogen bond is invoked as the cause for the increased stability of the C-terminal imidazole.

Melting curves give a measure of the thermal stability of the protein. A thermodynamic intermediate with pH-dependent reversibility is revealed. Comparisons with the electrochemistry and apoamicyanin suggest that the intermediate involves the region of the protein near the metal site. This region is destabilized in the P94F mutant; coupled with the evidence that the imidazole is stabilized under the same conditions confirms an original concept of the rack effect: a high energy configuration is stabilized at a cost to the rest of the protein.

Schottky barriers on compound semiconductors: I. HgSe highly electronegative contacts. II. Au Schottky barriers on n-Ga_(1-x)Al_xAs

I. HgSe is deposited on various semiconductors, forming a semimetal/semiconductor "Schottky barrier" structure. Polycrystalline, evaporated HgSe produces larger Schottky barrier heights on n-type semiconductors than does Au, the most electronegative of the elemental metals. The barrier heights are about 0.5 eV greater than those of Au on ionic semiconductors such as ZnS, and 0.1 to 0.2 eV greater for more covalently bonded semiconductors. A novel structure,which is both a lattice matched heterostructure and a Schottky barrier, is fabricated by epitaxial growth of HgSe on CdSe using hydrogen transport CVD. The Schottky barrier height for this structure is 0.73 ± 0.02 eV, as measured by the photoresponse method. This uncertainty is unusually small; and the magnitude is greater by about a quarter volt than is achievable with Au, in qualitative agreement with ionization potential arguments.

II . The Schottky barrier height of Au on chemically etched n-Ga_1-x Al_xAs was measured as a function of x. As x increases, the barrier height rises to a value of about 1.2 eV at x ≈ 0.45 , then decreases to about 1.0 eV as x approaches 0.83. The barrier height deviates in a linear way from the value predicted by the "common anion" rule as the AlAs mole fraction increases. This behavior is related to chemical reactivity of the Ga_1-x Al_xAs surface.

I. Foehn winds of southern California. II. Foehn wind cyclo-genesis. III. Weather conditions associated with the Akron disaster. IV. The Los Angeles storm of December 30, 1933 to January 1, 1934

I. Foehn winds of southern California.
An investigation of the hot, dry and dust laden winds occurring in the late fall and early winter in the Los Angeles Basin and attributed in the past to the influences of the desert regions to the north revealed that these currents were of a foehn nature. Their properties were found to be entirely due to dynamical heating produced in the descent from the high level areas in the interior to the lower Los Angeles Basin. Any dust associated with the phenomenon was found to be acquired from the Los Angeles area rather than transported from the desert. It was found that the frequency of occurrence of a mild type foehn of this nature during this season was sufficient to warrant its classification as a winter monsoon. This results from the topography of the Los Angeles region which allows an easy entrance to the air from the interior by virtue of the low level mountain passes north of the area. This monsoon provides the mild winter climate of southern California since temperatures associated with the foehn currents are far higher than those experienced when maritime air from the adjacent Pacific Ocean occupies the region.

II. Foehn wind cyclo-genesis.
Intense anticyclones frequently build up over the high level regions of the Great Basin and Columbia Plateau which lie between the Sierra Nevada and Cascade Mountains to the west and the Rocky Mountains to the east. The outflow from these anticyclones produce extensive foehns east of the Rockies in the comparatively low level areas of the middle west and the Canadian provinces of Alberta and Saskatchewan. Normally at this season of the year very cold polar continental air masses are present over this territory and with the occurrence of these foehns marked discontinuity surfaces arise between the warm foehn current, which is obliged to slide over a colder mass, and the Pc air to the east. Cyclones are easily produced from this phenomenon and take the form of unstable waves which propagate along the discontinuity surface between the two dissimilar masses. A continual series of such cyclones was found to occur as long as the Great Basin anticyclone is maintained with undiminished intensity.

III. Weather conditions associated with the Akron disaster.
This situation illustrates the speedy development and propagation of young disturbances in the eastern United States during the spring of the year under the influence of the conditionally unstable tropical maritime air masses which characterise the region. It also furnishes an excellent example of the superiority of air mass and frontal methods of weather prediction for aircraft operation over the older methods based upon pressure distribution.

IV. The Los Angeles storm of December 30, 1933 to January 1, 1934.
This discussion points out some of the fundamental interactions occurring between air masses of the North Pacific Ocean in connection with Pacific Coast storms and the value of topographic and aerological considerations in predicting them. Estimates of rainfall intensity and duration from analyses of this type may be made and would prove very valuable in the Los Angeles area in connection with flood control problems.

Magnetic behavior of basic iron(III) compounds. I. Magnetic behavior of the basic iron sulphates and basic iron chromate. II. Magnetic behavior of delta ferric oxide hydroxide

I. The thermomagnetic behavior and infrared spectroscopic features of KFe₃(SO₄)₂(OH)₆ (jarosite), (H₃O)Fe₃(SO₄)₂ (OH)₆ (hydronium jarosite), KFe₃(CrO₄)₂ (OH)₆, Fe(OH)SO₄ (basic iron sulfate), and Fe(OH)CrO₄ (basic iron chromate) are reported. Fe(OH)CrO₄ and KFe₃(CrO₄)₂ (OH)₆ are shown to be weak ferro magnets with Curie temperatures of 73 and 71 °K, respectively. This unusual magnetic behavior is rationalized in terms of the ionic spin configurations of the phases. Exchange coupling through chromate bridging groups is shown to be weak.

II. The magnetic behavior and the influence of preparative history on the magnetic behavior of δFeO(OH) is reported. δFeO(OH) is shown to be a fine-particulate, uniaxial, magnetic species. Magnetization data for this species are shown to be consistent with the existence of magnetically inactive layers surrounding magnetic particles.

I. The crystal structure of trimesic acid. II. Topics in crystallographic calculations

I. Trimesic acid (1, 3, 5-benzenetricarboxylic acid) crystallizes with a monoclinic unit cell of dimensions a = 26.52 A, b = 16.42 A, c = 26.55 A, and β = 91.53° with 48 molecules /unit cell. Extinctions indicated a space group of Cc or C2/c; a satisfactory structure was obtained in the latter with 6 molecules/asymmetric unit - C₅₄O₃₆H₃₆ with a formula weight of 1261 g. Of approximately 12,000 independent reflections within the CuK_α sphere, intensities of 11,563 were recorded visually from equi-inclination Weissenberg photographs.

The structure was solved by packing considerations aided by molecular transforms and two- and three-dimensional Patterson functions. Hydrogen positions were found on difference maps. A total of 978 parameters were refined by least squares; these included hydrogen parameters and anisotropic temperature factors for the C and O atoms. The final R factor was 0.0675; the final "goodness of fit" was 1.49. All calculations were carried out on the Caltech IBM 7040-7094 computer using the CRYRM Crystallographic Computing System.

The six independent molecules fall into two groups of three nearly parallel molecules. All molecules are connected by carboxylto- carboxyl hydrogen bond pairs to form a continuous array of sixmolecule rings with a chicken-wire appearance. These arrays bend to assume two orientations, forming pleated sheets. Arrays in different orientations interpenetrate - three molecules in one orientation passing through the holes of three parallel arrays in the alternate orientation - to produce a completely interlocking network. One third of the carboxyl hydrogen atoms were found to be disordered.

II. Optical transforms as related to x-ray diffraction patterns are discussed with reference to the theory of Fraunhofer diffraction.

The use of a systems approach in crystallographic computing is discussed with special emphasis on the way in which this has been done at the California Institute of Technology.

An efficient manner of calculating Fourier and Patterson maps on a digital computer is presented. Expressions for the calculation of to-scale maps for standard sections and for general-plane sections are developed; space-group-specific expressions in a form suitable for computers are given for all space groups except the hexagonal ones.

Expressions for the calculation of settings for an Eulerian-cradle diffractometer are developed for both the general triclinic case and the orthogonal case.

Photographic materials on pp. 4, 6, 10, and 20 are essential and will not reproduce clearly on Xerox copies. Photographic copies should be ordered.

Two topics in elementary particle physics. I. Crossing as a group and elimination of exotic channels. II. Real parts of meson-nucleon forward scattering amplitudes.

I. Crossing transformations constitute a group of permutations under which the scattering amplitude is invariant. Using Mandelstem's analyticity, we decompose the amplitude into irreducible representations of this group. The usual quantum numbers, such as isospin or SU(3), are "crossing-invariant". Thus no higher symmetry is generated by crossing itself. However, elimination of certain quantum numbers in intermediate states is not crossing-invariant, and higher symmetries have to be introduced to make it possible. The current literature on exchange degeneracy is a manifestation of this statement. To exemplify application of our analysis, we show how, starting with SU(3) invariance, one can use crossing and the absence of exotic channels to derive the quark-model picture of the tensor nonet. No detailed dynamical input is used.

II. A dispersion relation calculation of the real parts of forward π^±p and K^±p scattering amplitudes is carried out under the assumption of constant total cross sections in the Serpukhov energy range. Comparison with existing experimental results as well as predictions for future high energy experiments are presented and discussed. Electromagnetic effects are found to be too small to account for the expected difference between the π^-p and π⁺p total cross sections at higher energies.

I. Studies on alkaline phosphatase activity in developing sea urchin embryos. II. Studies on the activation of protein biosynthesis in sea urchin eggs at fertilization

I. Alkaline phosphatase activity in the developing sea urchin Lytechinus pictus has been investigated with respect to intensity at various stages, ionic requirements and intracellular localization. The activity per embryo remains the same in the unfertilized egg, fertilized egg and cleavage stages. At a time just prior to gastrulation (about 10 hours after fertilization) the activity per embryo begins to rise and increases after 300 times over the activity in the cleavage stages during the next 60 hours.

The optimum ionic strength for enzymatic activity shows a wide peak at 0.6 to 1.0. Calcium and magnesium show an additional optimum at a concentration in the range of 0.02 to 0.07 molar. EDTA at concentrations of 0.0001 molar and higher shows a definite inhibition of activity.

The intracellular localization of alkaline phosphatase in homogenates of 72-hour embryos has been studied employing the differential centrifugation method. The major portion of the total activity in these homogenates was found in mitochondrial and microsomal fractions with less than 5% in the nuclear fraction and less than 2% in the final supernatant. The activity could be released from all fractions by treatment with sodium deoxycholate.

II. The activation of protein biosynthesis at fertilization in eggs of the sea urchins Lytechinus pictus and Strongylocentrotus purpuratus has been studied in both intact eggs and cell-free homogenates. It is shown that homogenates from both unfertilized and fertilized eggs are dependent on potassium and magnesium ions for optimum amino acid incorporation activity and in the case of the latter the concentration range is quite narrow. Though the optimum magnesium concentrations appear to differ slightly in homogenates of unfertilized and fertilized eggs, in no case was it observed that unfertilized egg homogenates were stimulated to incorporate at a level comparable to that of the fertilized eggs.

An activation of amino acid incorporation into protein has also been shown to occur in parthenogenetically activated non-nucleate sea urchin egg fragments or homogenates thereof. This activation resembles that in the fertilized whole egg or fragment both in amount and pattern of activation. Furthermore, it is shown that polyribosomes form in these non-nucleate fragments upon artificial activation. These findings are discussed along with possible mechanisms for activation of the system at fertilization.