Order statistics of 1/f^{\alpha} signals

Order statistics of periodic, Gaussian noise with 1/f^{\alpha} power spectrum is investigated. Using simulations and phenomenological arguments, we find three scaling regimes for the average gap d_k= between the k-th and (k+1)-st largest values of the signal. The result d_k ~ 1/k known for independent, identically distributed variables remains valid for 0<\alpha<1. Nontrivial, \alpha-dependent scaling exponents d_k ~ k^{(\alpha -3)/2} emerge for 1<\alpha<5 and, finally, \alpha-independent scaling, d_k ~ k is obtained for \alpha>5. The spectra of average ordered values \epsilon_k= ~ k^{\beta} is also examined. The exponent {\beta} is derived from the gap scaling as well as by relating \epsilon_k to the density of near extreme states. Known results for the density of near extreme states combined with scaling suggest that \beta(\alpha=2)=1/2, \beta(4)=3/2, and beta(infinity)=2 are exact values. We also show that parallels can be drawn between \epsilon_k and the quantum mechanical spectra of a particle in power-law potentials.Comment: 8 pages, 5 figure

Representative bureaucracy: A cross-national analysis of gender (1996-2004)

To the best of my knowledge, this is the first paper of its kind to analyze the gender representativeness of bureaucrats cross-nationally. It discusses the dearth of comparative representative bureaucracy literature and places this paper within the context of American scholarly literature on representative bureaucracy. After commenting on the disconnect between these literatures and the broad-based international developing literature, it uses panel-corrected time series data in attempt to narrow these scholarly divisions through representative bureaucracy research. My analysis finds that higher levels of income per capita are statistically significant predictors of the percentage of female civil servants at the central government and sub-national levels while greater fiscal decentralization and the percentage of female parliamentarians are also statistically significant predictors at the central government level. It concludes by noting that the commonality discovered across countries of women serving more frequently at the sub-national than central government levels requires further investigation

Forming norms: informing diagnosis and management in sports medicine

Clinicians aim to identify abnormalities, and distinguish harmful from harmless abnormalities. In sports medicine, measures of physical function such as strength, balance and joint flexibility are used as diagnostic tools to identify causes of pain and disability and monitor progression in response to an intervention. Comparing results from clinical measures against ‘normal’ values guides decision-making regarding health outcomes. Understanding ‘normal’ is therefore central to appropriate management of disease and disability. However, ‘normal’ is difficult to clarify and definitions are dependent on context. ‘Normal’ in the clinical setting is best understood as an appropriate state of physical function. Particularly as disease, pain and sickness are expected occurrences of being human, understanding ‘normal’ at each stage of the lifespan is essential to avoid the medicalisation of usual life processes. Clinicians use physical measures to assess physical function and identify disability. Accurate diagnosis hinges on access to ‘normal’ reference values for such measures. However our knowledge of ‘normal’ for many clinical measures in sports medicine is limited. Improved knowledge of normal physical function across the lifespan will assist greatly in the diagnosis and management of pain, disease and disability

Validation of Computational Models of Auxiliary Ventilation Systems with Experimental Data

This paper reports the interim findings of a research program whose objective is to determine whether Computational Fluid Dynamic (CFD) models can be employed to accurately predict the airflow patterns within rapid development headings. In particular, the project aims to investigate the optimum set back distances for the ducts in order to adequately ventilate the face of the drivage. To validate the accuracy of the CFD model simulations measurements were obtained from a series of experiments performed on both scale models and within a full-scale surface gallery. The experimental scale-modeling program included making a series of pressure measurements across the face of the model for equivalent forcing duct setback distances of 5, 10 and 15 m (16, 33 and 50 ft). This pressure data was then plotted as contour plots and compared with the corresponding CFD predictions. A series of full-scale auxiliary ventilation trials were performed within a modified surface gallery. Three-dimensional velocity measurements were taken across a number of cross-sections using an ultrasonic anemometer. Velocity measurements were obtained for three forcing duct setback distances and for a typical force-exhaust overlap configuration

ECOSYSTEM APPROACH TO FISHERIES MANAGEMENT IN THE SOUTHERN BENGUELA: A WORKSHOP OVERVIEW

A workshop was held in Cape Town in December 2002 to introduce the concept of an ecosystem approach to fisheries (EAF) management in the southern Benguela, and to examine the options for implementing an EAF in South Africa. The workshop considered alternative modelling approaches that may have potential for an ecosystem approach to fisheries. Consensus was that an EAF should be implemented in South Africa through an incremental process, starting immediately. Ecosystem models can be used to provide guidance on reference points and broader management objectives still currently set on the basis of single-species assessments. Such additional information would be incorporated into the decision-making process, and comments received at a management level would also feed back to the modelling process. It was suggested that, at the scientific level, an ecosystem modelling perspective could be incorporated into existing single-species management recommendations by testing them with ecosystem models. Compilation of an “ecosystem considerations” document was recommended to initiate the process. It was proposed that a dedicated EAF working group be established in South Africa to advise on the process of implementing an EAF in the various fisheries, and to provide overarching guidance and to ensure consistency in integrating existing data and information for informing the management process

Renormalization group theory for finite-size scaling in extreme statistics

We present a renormalization group (RG) approach to explain universal features of extreme statistics, applied here to independent, identically distributed variables. The outlines of the theory have been described in a previous Letter, the main result being that finite-size shape corrections to the limit distribution can be obtained from a linearization of the RG transformation near a fixed point, leading to the computation of stable perturbations as eigenfunctions. Here we show details of the RG theory which exhibit remarkable similarities to the RG known in statistical physics. Besides the fixed points explaining universality, and the least stable eigendirections accounting for convergence rates and shape corrections, the similarities include marginally stable perturbations which turn out to be generic for the Fisher-Tippett-Gumbel class. Distribution functions containing unstable perturbations are also considered. We find that, after a transitory divergence, they return to the universal fixed line at the same or at a different point depending on the type of perturbation.Comment: 15 pages, 8 figures, to appear in Phys. Rev.

NOX-driven ROS formation in cell transformation of FLT3-ITD positive AML

In different types of myeloid leukemia, increased formation of reactive oxygen species (ROS) has been noted and associated with aspects of cell transformation including the promotion of leukemic cell proliferation and migration, as well as DNA-damage and accumulation of mutations. Work reviewed in this article has shown the involvement of NADPH oxidase (NOX)-derived ROS downstream of oncogenic protein-tyrosine kinases in both processes, and the related pathways have been partially identified. FLT3-ITD, an important oncoprotein in a subset of AML, causes activation of AKT and subsequently stabilization of p22phox, a regulatory subunit for NOX1-4. This process is linked to ROS formation and DNA damage. Moreover, FLT3-ITD signaling through STAT5 enhances expression of NOX4, ROS formation and inactivation of the protein-tyrosine phosphatase DEP-1/PTPRJ, a negative regulator of FLT3 signaling, by reversible oxidation of its catalytic cysteine residue. Genetic inactivation of NOX4 restored DEP-1 activity and attenuated cell transformation by FLT3-ITD in vitro and in vivo. Future work is required to further explore these mechanisms and their causal involvement in leukemic cell transformation, which may result in the identification of novel candidate targets for therapy

Synchronization and multi-mode dynamics of mutually coupled semiconductor lasers

Dynamics of coupled semiconductor lasers is investigated by numerical simulations. A realistic laser simulation engine is used to study the synchronization and dynamical regime in two mutually coupled Fabry-Perot and/or DFB lasers. Both, single- and multi-mode operation regimes are studied with emphasis on the role of the multiple laser-cavity modes. Our findings indicate that the two laser synchronize within each laser-cavity mode, while the synchronization across different cavity modes is significantly weaker

Functional Investigation of Iron-Responsive Microsomal Proteins, including MirC, in Aspergillus fumigatus

The functionality of many microsome-associated proteins which exhibit altered abundance in response to iron limitation in Aspergillus fumigatus is unknown. Here, we generate and characterize eight gene deletion strains, and of most significance reveal that MirC (AFUA_2G05730) contributes to the maintenance of intracellular siderophore [ferricrocin (FC)] levels, augments conidiation, confers protection against oxidative stress, exhibits an intracellular localization and contributes to fungal virulence in the Galleria mellonella animal model system. FC levels were unaffected following deletion of all other genes encoding microsome-associated proteins. MirC does not appear to play a role in either siderophore export from, or uptake into, A. fumigatus. Label-free quantitative proteomic analysis unexpectedly revealed increased abundance of siderophore biosynthetic enzymes. In addition, increased expression of hapX (7.2 and 13.8-fold at 48 and 72 h, respectively; p < 0.001) was observed in ΔmirC compared to wild-type under iron-replete conditions by qRT-PCR. This was complemented by significantly elevated extracellular triacetylfusarinine C (TAFC; p < 0.01) and fusarinine C (FSC; p < 0.05) siderophore secretion. We conclude that MirC plays an important role in FC biosynthesis and contributes to the maintenance of iron homeostasis in A. fumigatus

A Multicriteria Assessment of Forage or Concentrate-Based Finishing Diets for Temperate Pasture-Based Suckler Beef Production Systems

This study evaluated the effect of contrasting ‘finishing’ diets on animal performance, meat nutritional value, land use, food-feed competition, farm economics and greenhouse gas (GHG) emissions in temperate pasture-based suckler weanling-to-steer beef systems. Post-weaning, eight-month-old, spring-born, late-maturing breed steers (333 kg) were assigned to one of three systems: (1) Grass silage + 1.2 kg concentrate DM (148 days), followed by pasture (123 days) and finished on ad libitum concentrates (120 days) - slaughter age, 21 months (GRAIN); (2) as per (1) but pasture (196 days) and finished on grass silage ad libitum + 3.5 kg concentrate DM (124 days) - slaughter age, 24 months (SIL+GRAIN); and (3) grass silage-only (148 days), pasture (196 days), silage-only (140 days) and finished on pasture (97 days) - slaughter age, 28 months (FORAGE). The mean target carcass weight was 390 kg for each system. Data generated was used to parameterise a farm-level beef systems model. Measured concentrate DM intake was 1187, 606 and 0 kg/head, and average daily gain was 0.83, 0.72 and 0.62 kg for GRAIN, SIL+GRAIN and FORAGE, respectively. Direct (pasture) land use was lowest for GRAIN. FORAGE was more profitable and was the only net producer of human edible protein and energy/ha. GRAIN produced the lowest GHG emissions per animal and meat essential amino acid concentration. FORAGE was more favourable for GHG emissions per kg of net (produced vs. consumed) production of human edible protein. Muscle amino acid and saturated fatty acid concentrations did not differ between the production systems, but FORAGE had the highest muscle concentration of omega-3 poly-unsaturated fatty acids. Differences in muscle mineral concentration were small. In conclusion, there are inverse relationships between food-feed competition, land-use, economics and GHG emissions per unit of product among different systems