Cytochrome P450 oxidoreductase participates in nitric oxide consumption by rat brain

In low nanomolar concentrations, NO (nitric oxide) functions as a transmitter in brain and other tissues, whereas near-micromolar NO concentrations are associated with toxicity and cell death. Control of the NO concentration, therefore, is critical for proper brain function, but, although its synthesis pathway is well-characterized, the major route of breakdown of NO in brain is unclear. Previous observations indicate that brain cells actively consume NO at a high rate. The mechanism of this consumption was pursued in the present study. NO consumption by a preparation of central glial cells was abolished by cell lysis and recovered by addition of NADPH. NADPH-dependent consumption of NO localized to cell membranes and was inhibited by proteinase K, indicating the involvement of a membrane-bound protein. Purification of this activity yielded CYPOR (cytochrome P450 oxidoreductase). Antibodies against CYPOR inhibited NO consumption by brain membranes and the amount of CYPOR in several cell types correlated with their rate of NO consumption. NO was also consumed by purified CYPOR but this activity was found to depend on the presence of the vitamin E analogue Trolox (6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid), included in the buffer as a precaution against inadvertent NO consumption by lipid peroxidation. In contrast, NO consumption by brain membranes was independent of Trolox. Hence, it appears that, during the purification process, CYPOR becomes separated from a partner needed for NO consumption. Cytochrome P450 inhibitors inhibited NO consumption by brain membranes, making these proteins likely candidates

Long run equilibrium estimation and inference: a non-parametric application

Phillips (1988a) has demonstrated that the long run parameters of a continuous time error correction model (ECM) involving nonstationary variables can be estimated from a corresponding discrete time ECM. He suggests Hannan efficient and band spectral frequency domain procedures for estimation and inference, anticipating they would provide significant advantages over the parametric methods traditionally used for continuous time models. A further advantage of Phillips' proposed methodology is that conventional asymptotic chisquared hypothesis testing can be carried out. This paper provides an early successful application of that methodology, using Australian consumption and income data. The spectral regression estimates are relatively straight forward to compute, with only a few iterations being required. The spectral estimates are not sensitive to alternative initial estimates. The application also highlights the potential importance of non-parametric estimators. Empirically, the long run consumption function estimates obtained are sufficiently realistic for it to be worthwhile exploring conditional short run dynamic relations and other macroeconomic data sets. Our hypothesis testing procedures are consistent across the aggregate and disaggregated data sets used, and between the unit root and cointegration stages of the investigation. A surprising result is that the null of no cointegration between aggregate real consumption and household disposable income cannot be rejected

Enhancing pasture stability and profitability for producers in Poplar Box and Silver-leaved Ironbark woodlands.

Over 7 years, this project collected data about the pasture, tree and soil surface dynamics of two major Aristida/Bothriochloa pasture types within the eucalypt woodlands of central Queensland. Six different grazing management scenarios were compared ecologically and economically, along with the effects of spring burns and tree killing. Heavy stocking (3-4 ha per adult equivalent) produced the greatest short-term financial return from healthy pastures but was not a sustainable practice and long-term cash returns were no better than those from moderate stocking. The environmental benefits of moderate grazing over heavy grazing were very clear. Light stocking produced better environmental outcomes compared to moderate stocking but was clearly inferior with respect to economic returns. Killing silver-leaved ironbark trees near Rubyvale produced no measurable improvement in pasture growth or quality for at least 6 years whereas at Injune the same treatment of poplar box trees resulted in an immediate and large enhancement in pasture production and carrying capacity. The gritty red duplex soil at Rubyvale was much more erodible than the grey solodic at Injune although the latter becomes very erodible if the stable surface soil is breached. Good seasonal rainfall produced faster changes in pasture composition than extremes of grazing management. The perennial grasses were easier to recruit than to eliminate by grazing management changes

“Facing” leaders: Facial expression and leadership perception

This experimental study investigated the effect of a leader's expression of happy versus nervous emotions on subsequent perceptions of leadership and ratings of traits associated with implicit leadership theories (ILTs). Being fast and universally understood, emotions are ideal stimuli for investigating the dynamic effects of ILTs, which were understood in this study in terms of the constraints that expressed emotions impose on the connectionist networks that activate ILTs. The experimental design contrasted videotaped and still frame presentations of a leadership event; however, this methodological factor had no significant effects and analyses were thus collapsed across this factor. Key findings were that the expression of a happy versus nervous emotion at the end of a problem-solving sequence had multiple effects: happy emotions resulted in higher leadership ratings, higher trait ratings, greater correlations among trait ratings, and greater dependence of trait ratings on leadership perceptions. An exploratory model suggested that leadership impressions mediated the effects of facial emotions on trait ratings. The discussion further links the study findings with interpretations in terms of ILTs and many types of constraints on these cognitive structures. It also suggests ways to integrate these ideas with advances in neuroscience research

Perceptions of Time, Cost and Quality Management on Building Projects

This paper examines the relative intrinsic importance of the effective management of projecttime, cost and quality in the attainment of client objectives. The findings from a questionnairesurvey are presented. The survey explored the perceptions of South Africanclients concerning their objectives and the project time, cost and quality management associatedwith building procurement systems in South Africa. The findings indicate thatmis-perceptions exist between clients, contractors and building professionals regardingthe time, cost and quality management associated with building projects, and the contributionthis makes to the attainment of client objectives

Compressed sensing current mapping of PV devices using a DLP projector

A commercial Digital Light Processing (DLP) projector has been utilised for compressed sensing current mapping of photovoltaic (PV) devices. Through the projector, the necessary patterns are projected to apply compressive sampling for measurement acquisition. The reconstruction of the current map is achieved by an optimisation algorithm. The main advantage of this method is that measurement time is significantly reduced, compared to conventional LBIC measurement systems. This is achieved mainly by acquiring fewer measurements than a raster scan would need. Initial current maps of cells and modules have been acquired, showing the feasibility of the method. The issues of such a system have been investigated and its potential for fast and simple current mapping of PV modules is demonstrated

A simple optical setup for current mapping of small area PV devices using different sampling strategies

An optical setup for current mapping of photovoltaic devices is presented. It is based on a digital micro-mirror device (DMD) and a small number of additional optical elements making the implementation simple and cost effective. The specific properties of the DMD chip enable the application of two different sampling methods; point by point sampling and compressive sampling. Both sampling strategies are compared and cases when each one of them performs better are investigated. It is shown that compressive sampling can significantly enhance weak current signals and provide current maps in the cases when the point by point current signal is below the noise threshold

Compressive current response mapping of photovoltaic devices using MEMS mirror arrays

Understanding the performance and aging mechanisms in photovoltaic devices requires a spatial assessment of the device properties. The current dominant technique, electroluminescence, has the disadvantage that it assesses radiative recombination only. A complementary method, laser beam-induced current (LBIC), is too slow for high-throughput measurements. This paper presents the description, design, and proof of concept of a new measurement method to significantly accelerate LBIC measurements. The method allows mapping of the current response map of solar cells and modules at drastically reduced acquisition times. This acceleration is achieved by projecting a number of mathematically derived patterns on the sample by using a digital micromirror device (DMD). The spatially resolved signal is then recovered using compressed sensing techniques. The system has fewer moving parts and is demonstrated to require fewer overall measurements. Compared with conventional LBIC imaging using galvanic mirror arrangements or xy scanners, the use of a DMD allows a significantly faster and more repeatable illumination of the device under test. In this proof-of-concept instrument, sampling patterns are drawn from Walsh–Hadamard matrices, which are one of the many operators that can be used to realize this technique. This has the advantage of the signal-to-noise ratio of the measurement being significantly increased and thus allows elimination of the standard lock-in techniques for signal detection, reducing measurement costs, and increasing measurement speed further. This new method has the potential to substantially decrease the time taken for measurement, which demonstrates a dramatic improvement in the utility of LBIC instrumentation

Quark Mass Textures and sin 2 beta

Recent precise measurements of sin 2 beta from the B-factories (BABAR and BELLE) and a better known strange quark mass from lattice QCD make precision tests of predictive texture models possible. The models tested include those hierarchical N-zero textures classified by Ramond, Roberts and Ross, as well as any other hierarchical matrix Ansatz with non-zero 12 = 21 and vanishing 11 and 13 elements. We calculate the maximally allowed value for sin 2 beta in these models and show that all the aforementioned models with vanishing 11 and 13 elements are ruled out at the 3 sigma level. While at present sin 2 beta and |Vub/Vcb| are equally good for testing N-zero texture models, in the near future the former will surpass the latter in constraining power.Comment: 1+20 pages, 2 figures, JHEP3 clas

Towards current mapping of photovoltaic devices by compressed imaging

A new photovoltaic (PV) device current mapping method has been developed, utilizing the recently introduced compressed sensing sampling theory. The aim is to significantly reduce measurement time of Light Beam Induced Current measurements. A prototype setup has been built at National Physics Laboratory (NPL) to implement the method. Initial results are presented and illustrate the feasibility of the method