bluuebunny/crossref_metadata_2025 huggingface dataset:
Generic Uniform Convergence
Authors: Andrews Donald W.K.
Published: October 2010

This paper presents several generic uniform convergence results that include generic uniform laws of large numbers. These results provide conditions under which pointwise convergence almost surely or in probability can be strengthened to uniform convergence. The results are useful for establishing asymptotic properties of estimators and test statistics.

The results given here have the following attributes, (1) they extendresults of Newey to cover convergence almost surely as well as convergence in probability, (2) they apply to totally bounded parameter spaces (rather than just to compact parameter spaces), (3) they introduce a set of conditions for a generic uniform law of large numbers that has the attribute of giving the weakest conditions available for i.i.d. contexts, but which apply in some dependent nonidentically distributed contexts as well, and (4) they incorporate and extend themain results in the literature in a parsimonious fashion.
A Bootstrap Test for Positive Definiteness of Income Effect Matrices
Authors: Härdle Wolfgang , Hart Jeffrey D.
Published: October 2010

Positive definiteness of income effect matrices provides a sufficient condition for the law of demand to hold. Given cross section household expenditure data, empirical evidence for the law of demand can be obtained by estimating such matrices. Härdle, Hildenbrand, and Jerison used the bootstrap method to simulate the distribution of the smallest eigenvalue of random matrices and to test their positive definiteness. Here, theoretical aspects of this bootstrap test of positive definiteness are considered. The asymptotic distribution of the smallest eigenvalue , of the matrix estimate is obtained. This theory applies generally to symmetric, asymptotically normal random matrices. A bootstrap approximation to the distribution of is shown to converge in probability to the asymptotic distribution of . The bootstrap test is illustrated using British family expenditure survey data.
Winsorized Mean Estimator for Censored Regression
Authors: Lee Myoung-Jae
Published: October 2010

We introduce a semiparametric estimator for the censored linear regression model. It is based on the regression version of Huber's [6] M-estimator. It includes Powell's [19] censored least absolute deviations estimator as a special case and is related to Powell's [20] symmetrically censored least-squares estimator. We prove strong consistency and derive its asymptotic distribution which is √n-consistent with an easily computable covariance matrix. A small-scale simulation study shows that it works quite well in various cases.
Nonparametric Regression Tests Based on Least Squares
Authors: Yatchew Adonis John
Published: October 2010

This paper proposes tests on semiparametric models based on the sum of squared residuals from a least-squares procedure. Smoothness conditions are imposed on the nonparametric portion of the model to obtain asymptotic normality of the sum of squared residuals. The approach yields tests of specification, significance, smoothness and concavity and allows for heteroskedastic residuals.
A Test for Functional Form Against Nonparametric Alternatives
Authors: Wooldridge Jeffrey M.
Published: October 2010

A test for neglected nonlinearities in regression models is proposed. The test is of the Davidson-MacKinnon type against an increasingly rich set of non-nested alternatives, and is based on sieve estimation of the alternative model. For the case of a linear parametric model, the test statistic is shown to be asymptotically standard normal under the null, while rejecting with probability going to one if the linear model is misspecified. A small simulation study suggests that the test has adequate finite sample properties, but one must guard against over fitting the nonparametric alternative.
On Efficiency of Methods of Simulated Moments and Maximum Simulated Likelihood Estimation of Discrete Response Models
Authors: Lee Lung-Fei
Published: October 2010

This article considers methods of simulated moments for estimation of discrete response models. It is possible to use the same set of random numbers to simulate the choice probabilities for each individual in the sample. In addition to the method of simulated moments of McFadden, we have considered also maximum simulated likelihood estimation methods. An asymptotic theory for such procedures is provided. The estimators are shown to be consistent and asymptotically normal by the theory of generalizedU-statistics. Asymptotic efficiency is discussed. Monte Carlo experiments on the finite sample performance of the estimators are reported.
The Asymptotic Local Structure of the Cox Modified Likelihood-Ratio Statistic for Testing Non-Nested Hypotheses
Authors: Szroeter Jerzy
Published: October 2010

It is shown that the Cox modified likelihood-ratio statistic for testing partially non-nested hypothesesH0andH1is asymptotically equivalent to a bilinear form in nondegenerate asymptotically normal random vectors for sequences of data-generating processes converging to the intersection ofH0andH1but not necessarily belonging to eitherH0orH1. One of the asymptotically normal vectors is the complete parametric encompassing vector of Mizon and Richard, while the other is a close relative. The results are valid regardless of whether or not the data-generating process is exponential and imply that the Cox statistic is not generally asymptotically locally normal. This corrects an assumption made in recent literature.
The History of Continuous-Time Econometric Models
Authors: Bergstrom A. R.
Published: October 2010

Although it is only during the last decade that continuous-time models have been extensively used in applied econometric work, the development of statistical methods applicable to such models commenced over 40 years ago. The first significant contribution to the problem of estimating the parameters of continuous-time stochastic models from discrete data was made by the British statistician Bartlett [1946] only three years after the pioneering contribution of Haavelmo [1943] on simultaneous equations models. Moreover, by this time the fundamental mathematical theory of continuous-time stochastic models was already well developed, major contributions having been made by some of the leading mathematicians of the twentieth century, including Einstein, Weiner, and Kolmogorov.
The Estimation of Linear Stochastic Models with Covariance Restrictions
Authors: Pollock D.S.G.
Published: October 2010

The purpose of this paper is to provide a systematic treatment of the problem of estimation in systems of linear stochastic equations where some of the disturbances are uncorrelated and where the identifying equations are equivalent to a linear system.
Partially Adaptive Estimation of Regression Models via the Generalized T Distribution
Authors: McDonald James B. , Newey Whitney K.
Published: October 2010

This paper considers M-estimators of regression parameters that make use of a generalized functional form for the disturbance distribution. The family of distributions considered is the generalized t (GT), which includes the power exponential or Box-Tiao, normal, Laplace, and t distributions as special cases. The corresponding influence function is bounded and redescending for finite “degrees of freedom.” The regression estimators considered are those that maximize the GT quasi-likelihood, as well as one-step versions. Estimators of the parameters of the GT distribution and the effect of such estimates on the asymptotic efficiency of the regression estimates are discussed. We give a minimum-distance interpretation of the choice of GT parameter estimate that minimizes the asymptotic variance of the regression parameters.
Weak Convergence of Sample Covariance Matrices to Stochastic Integrals Via Martingale Approximations
Authors: Phillips P.C.B.
Published: October 2010

Under general conditions the sample covariance matrix of a vector martingale and its differences converges weakly to the matrix stochastic integral ∫01BdB′, where B is vector Brownian motion. For strictly stationary and ergodic sequences, rather than martingale differences, a similar result obtains. In this case, the limit is ∫01BdB′ + Λ and involves a constant matrix Λ of bias terms whose magnitude depends on the serial correlation properties of the sequence. This note gives a simple proof of the result using martingale approximations.
Relationships between lexical and phonological development in young children*
Authors: STOEL-GAMMON CAROL
Published: October 2010

Our understanding of the relationships between lexical and phonological development has been enhanced in recent years by increased interest in this area from language scientists, psychologists and phonologists. This review article provides a summary of research, highlighting similarities and differences across studies. It is suggested that the research falls into two categories with different goals and different methodological approaches: (1) child-centered studies that examine the influences active in the prelinguistic and early-word period, emphasizing individual developmental patterns and the active role played by the child; and (2) studies inspired by research on word processing in adults; these focus on the effects of the phonological and lexical characteristics of the ambient language on underlying representations and word learning in children. The article concludes with suggestions for integrating the findings from the two approaches and for future research.
Lexicon–phonology relationships and dynamics of early language development – a commentary on Stoel-Gammon's ‘Relationships between lexical and phonological development in young children’
Authors: EDWARDS JAN , MUNSON BENJAMIN , BECKMAN MARY E.
Published: October 2010

We applaud Stoel-Gammon's (this issue) call for a more comprehensive account of the relationship between lexicon and phonology, and we strongly endorse her suggestions for future research. However, we think that it will not be enough simply to integrate findings and methods from the adult-centered and child-centered literatures. Both of these literatures suggest that we need to rethink standard assumptions about what phonological representations are and how they emerge to support the very large vocabularies that speakers develop over the course of a lifetime. Our commentary focuses on three themes relevant to this reconceptualization.
Stepping backwards in development: integrating developmental speech perception with lexical and phonological development – a commentary on Stoel-Gammon's ‘Relationships between lexical and phonological development in young children’*
Authors: ZAMUNER TANIA S.
Published: October 2010

Within the subfields of linguistics, traditional approaches tend to examine different phenomena in isolation. As Stoel-Gammon (this issue) correctly states, there is little interaction between the subfields. However, for a more comprehensive understanding of language acquisition in general and, more specifically, lexical and phonological development, we must consider relations between multiple subfields. That is, by examining the interactions between these subfields, a greater understanding of lexical and phonological development can emerge. For instance, the interaction between phonology, syntax and semantics is demonstrated in recent work looking at how phonological patterns can provide a basis for inferring a word's lexical category (such as nouns and verbs) (Christiansen, Onnis & Hockema, 2009; Lany & Saffran, 2010).
Bipolar input to melanopsin containing ganglion cells in primate retina
Authors: GRÜNERT ULRIKE , JUSUF PATRICIA R. , LEE SAMMY C.S. , NGUYEN DUNG THAN
Published: October 2010

Two morphological types of melanopsin-expressing ganglion cells have been described in primate retina. Both types show intrinsic light responses as well as rod- and cone-driven ON-type responses. Outer stratifying cells have their dendrites close to the inner nuclear layer (OFF sublamina); inner stratifying cells have their dendrites close to the ganglion cell layer (ON sublamina). Both inner and outer stratifying cells receive synaptic input via ribbon synapses, but the bipolar cell types providing this input have not been identified. Here, we addressed the question whether the diffuse (ON) cone bipolar type DB6 and/or rod bipolar cells contact melanopsin-expressing ganglion cells. Melanopsin containing ganglion cells in marmoset (Callithrix jacchus) and macaque (Macaca fascicularis) retinas were identified immunohistochemically; DB6 cells were labeled with antibodies against the carbohydrate epitope CD15, rod bipolar cells were labeled with antibodies against protein kinase C, and putative synapses between the two cells types were identified with antibodies against piccolo. For one inner cell, nearly all of the DB6 axon terminals that overlap with its dendrites in the two-dimensional space show areas of close contact. In vertical sections, the large majority of the areas of close contact also contain a synaptic punctum, suggesting that DB6 cells contact inner melanopsin cells. The output from DB6 cells accounts for about 30% of synapses onto inner melanopsin cells. Synaptic contacts between rod bipolar axons and inner dendrites were not observed. In the OFF sublamina, about 10% of the DB6 axons are closely associated with dendrites of outer cells, and in about a third of these areas, axonal en passant synapses are detected. This result suggests that DB6 cells may also provide input to outer melanopsin cells.
Contribution of melt in the Beaufort Sea to the decline in Arctic multiyear sea ice coverage: 1993–2009
Authors: Kwok R. , Cunningham G. F.
Published: October 2010

For the summers of 1993 through 2009, we estimate the loss of multiyear sea ice (MYI) area in the Beaufort Sea due to melt. Parcels of MYI in April are traced into the Beaufort Sea where they melt as the ice edge retreats. Net loss of area (with fractional MYI coverage >50%) over the 17‐year period is ∼900 × 103 km2. Three‐quarters of that area, ∼10% of the area of the Arctic Ocean, was lost after 2000. There is a clear positive trend in the record, with a distinct peak of 213 × 103 km2 in 2008; this is twice the summer outflow at the Fram Strait that year. The net melt area of 490 × 103 km2 between 2005 and 2008 accounts for nearly 32% of the net loss of 1.54 × 106 km2 of Arctic Ocean MYI coverage over the same period. Volume loss, for the years with ICESat thickness (2004–2009), is highest at 473 km3 in 2008 followed by 320 km3 in 2007. Net loss in MYI volume for the six summers is ∼1400 km3. This is ∼20% of the loss in MYI volume of 6300 km3 during 2004–2008. This adds to the freshwater content of the Arctic Ocean and locally to the freshening of the Beaufort Gyre.
Spatial distribution of relativistic electron precipitation during a radiation belt depletion event
Authors: Millan R. M. , Yando K. B. , Green J. C. , Ukhorskiy A. Y.
Published: October 2010

We present observations from the NOAA‐15 MEPED telescopes during a radiation belt depletion event on January 19–20, 2000 to investigate the spatial extent of electron precipitation during this interval. Precipitation mapped to the equatorial plane was confined to radial distances less than ∼6.5 Earth radii, indicating that precipitation was not the direct cause of the decrease in trapped flux observed by GOES. We found an enhanced day–night magnetic field asymmetry during the event, suggesting that magnetopause losses may have been responsible. Precipitation at lower L‐values was observed by POES on the dusk passes (18:30–21:00 MLT), but not on the dawn passes, and was observed in conjugate hemispheres. These observations suggest that both precipitation and magnetopause losses were acting during this flux depletion event.
Deformation of MnGeO3 post‐perovskite at lower mantle pressure and temperature
Authors: Hirose Kei , Nagaya Yukio , Merkel Sébastien , Ohishi Yasuo
Published: October 2010

Strong seismic anisotropy observed in the Earth's lowermost mantle, the D″ layer, is likely attributed to the lattice‐preferred orientation (LPO) of its predominant mineral, magnesium‐silicate post‐perovskite (PPv). Here we report simultaneous high‐pressure and ‐temperature plastic deformation experiments on MnGeO3 PPv from 77 to 111 GPa and from 83 to 105 GPa at 2000 K using the membrane‐type diamond‐anvil cell (DAC). Radial X‐ray diffraction measurements demonstrate that the (001) plane aligned perpendicular to the compression direction, indicating deformation dominated by slip on (001). In strong contrast to other slip planes proposed previously, the (001) slip plane can cause significant shear‐wave splitting with polarization in line with seismic observations. D″ anisotropy can therefore be primarily reconciled with LPO of the PPv phase.
Influence of hot plasma pressure on the global structure of Saturn’s magnetodisk
Authors: Achilleos N. , Guio P. , Arridge C. S. , Sergis N. , Wilson R. J. , Thomsen M. F. , Coates A. J.
Published: October 2010

Using a model of force balance in Saturn's disk‐like magnetosphere, we show that variations in hot plasma pressure can change the magnetic field configuration. This effect changes (i) the location of the magnetopause, even at fixed solar wind dynamic pressure, and (ii) the magnetic mapping between ionosphere and disk. The model uses equatorial observations as a boundary condition—we test its predictions over a wide latitude range by comparison with a Cassini high‐inclination orbit of magnetic field and hot plasma pressure data. We find reasonable agreement over time scales larger than the period of Saturn kilometric radiation (also known as the camshaft period).
On claimed ULF seismogenic fractal signatures in the geomagnetic field
Authors: Masci Fabrizio
Published: October 2010

During the last ten years, fractal analysis of ultra low frequency (ULF) geomagnetic field components has been proposed as one of the most promising tools to highlight magnetic precursory signals possibly generated by the preparation processes of earthquakes. Several papers claim seismogenic changes in the fractal features of the geomagnetic field some months before earthquakes occur. The target of the present paper is to put forth a qualitative investigation on the fractal characteristics of ULF magnetic signatures that previous authors have claimed to be related without doubt to strong earthquakes. This analysis takes into account both the temporal evolution of the geomagnetic field fractal parameters reported in previous researches and the temporal evolution of global geomagnetic activity. Running averages of the geomagnetic indices ΣKp and Ap are plotted into the original figures from the previous publications. This simple analysis shows that the fractal features of the ULF geomagnetic field are closely related to the geomagnetic activity both before and after the earthquake occurs. The correlation between the geomagnetic field fractal parameters and geomagnetic activity is clearly shown over both long and short time scales. In light of this, the present paper shows that fractal behaviors of previously claimed seismogenic ULF magnetic signatures depend mainly on geomagnetic activity due to solar‐terrestrial interaction. Therefore, previously reported association with the preparation process of the earthquake is dubious.
Wave‐induced transport of atmospheric constituents and its effect on the mesospheric Na layer
Authors: Gardner Chester S. , Liu Alan Z.
Published: October 2010

Extensive observations of winds, temperatures, and Na densities between 80 and 105 km at the Starfire Optical Range, New Mexico, are used to characterize the seasonal variations of the vertical flux of atomic Na and its impact on the Na layer. The largely downward Na flux and its convergence enhance the transport of Na from meteoric sources above 90 km to chemical sinks below 85 km, altering the height, width, and abundance of the Na layer. From theoretical considerations, it is shown that the effective vertical velocity associated with dynamical transport by dissipating waves is the same for all species and is about 3 times faster than the effective heat transport velocity. Dynamical transport is generally downward with velocities as high as −5 cm s−1 below 90 km in midwinter when and where gravity wave activity and dissipation are strongest. Chemically induced transport of atomic Na by both dissipating and nondissipating waves is also significant so that the total effective transport velocity for Na below 90 km approaches −8 cm s−1 in midwinter. The observations show that at the solstices, dynamical and chemical transport play far more important roles than turbulent mixing in transporting Na downward, while at the equinoxes the impacts of all three wave‐induced transport mechanisms are comparable. These results have important implications for chemical modeling of the mesopause region.
Validating the reported random errors of ACE‐FTS measurements
Authors: Toohey M. , Strong K. , Bernath P. F. , Boone C. D. , Walker K. A. , Jonsson A. I. , Shepherd T. G.
Published: October 2010

In order to validate the reported precision of space‐based atmospheric composition measurements, validation studies often focus on measurements in the tropical stratosphere, where natural variability is weak. The scatter in tropical measurements can then be used as an upper limit on single‐profile measurement precision. Here we introduce a method of quantifying the scatter of tropical measurements which aims to minimize the effects of short‐term atmospheric variability while maintaining large enough sample sizes that the results can be taken as representative of the full data set. We apply this technique to measurements of O3, HNO3, CO, H2O, NO, NO2, N2O, CH4, CCl2F2, and CCl3F produced by the Atmospheric Chemistry Experiment–Fourier Transform Spectrometer (ACE‐FTS). Tropical scatter in the ACE‐FTS retrievals is found to be consistent with the reported random errors (RREs) for H2O and CO at altitudes above 20 km, validating the RREs for these measurements. Tropical scatter in measurements of NO, NO2, CCl2F2, and CCl3F is roughly consistent with the RREs as long as the effect of outliers in the data set is reduced through the use of robust statistics. The scatter in measurements of O3, HNO3, CH4, and N2O in the stratosphere, while larger than the RREs, is shown to be consistent with the variability simulated in the Canadian Middle Atmosphere Model. This result implies that, for these species, stratospheric measurement scatter is dominated by natural variability, not random error, which provides added confidence in the scientific value of single‐profile measurements.
Longitudinal outcome of first episode psychosis in adolescence
Authors: Pencer A. , Addington J. , Hogg L. , Addington D.
Published: October 2010

There is little research examining the longitudinal course and outcome of psychotic disorders in adolescence. The purpose of this study was to examine outcome in 50 adolescents 1 and 2 years after admission to the Calgary Early Psychosis programme (EPP) a comprehensive programme for early psychosis. Measures of outcome included hospital admissions, relapse rates, suicide attempts, positive and negative symptoms (PANSS), depression (CDSS), Quality of life (QOL) substance use and cognitive functioning. 50 adolescents were assessed on these measures at 12 and 24 months and compared to a group of 50 adults from EPP. The adolescent group demonstrated significant improvements in positive symptoms, depression, quality of life, alcohol and drug use (P < 0. P < 0.001). There were no differences between the adolescents and adults. These results demonstrate that adolescents with psychosis have similar outcome to as adults after 1 and 2 years of optimal treatment, even though they present earlier for treatment. However, it is possible thatthe positive effects of earlier treatment may be offset by the possible poor prognosis of the earlier age of onset of this group.
Skin Microbiome in Disease States: Atopic Dermatitis and Immunodeficiency
Authors: Segre Julia , Kong Heidi
Published: October 2010

The Human Microbiome Project seeks to explore the diversity of microbiota that resides in and on the human body, including the skin, in health and disease. The NIH Intramural Skin Microbiome Consortium (NISMC) is a trans-disciplinary group of experts engaged in the practice of genomics, bioinformatics, large-scale DNA sequencing, dermatology, immunology, allergy, infectious disease, and clinical microbiology. Atopic dermatitis (AD, “eczema”) is a chronic relapsing skin disorder that affects ~15% of U.S. children and is associated with $1 billion of medical costs annually. AD is characterized by dry, itchy skin, infiltrated with immune cells. Colonization by _Staphylococcus aureus_ (S. aureus) is ten-fold more common in AD patients and is associated with disease flares. We hypothesize that, in addition to S. aureus, AD may also be associated with additional microbes and/or selective shifts of commensal microbes that are relevant to disease progression. The NISMC seeks to define the microbiota that resides in and on the skin and nares of three patient groups, all of whom have eczematous lesions and are currently seen at the NIH Clinical Center: (1) AD patients; (2) Wiskott-Aldrich syndrome (WAS) patients; and (3) Hyper IgE syndrome (HIES) syndrome patients.Examination of the microbiome of patients with WAS or HIES syndromes, both rare immunodeficiencies, will advance our understanding of how an individual’s immune system shapes their cutaneous microbial community. We are performing a prospective longitudinal study that follows these groups of patient thorough the cycles of eczema flares, ascertaining clinical data and samples at each stage. To analyze the longitudinal samples obtained from both affected and unaffected skin sites, we will use an integrated approach including: (1) extensive characterization of bacterial diversity; (2) analysis of fungal diversity; (3) generation of whole-genome sequences of novel skin microbial isolates; and (4) metagenomic sequencing to assess microbial abundance and deduce metabolic activities. Examination of the microbial communities on affected and unaffected skin of patients with eczema will yield insights into the gene-environment interactions relevant to these diseases.
Gas phase constant pressure heat capacities (C~p,gas~) for the C~1~ through C~10~ straight chain alkanes, isobutane, hydrogen atom, hydroxyl and methyl radicals, and water between 298.15 and 1500 K: A comparison of theoretical values against experimental data
Authors: Rayne Sierra , Forest Kaya
Published: October 2010

Gas phase constant pressure heat capacities (C~p,gas~) for the C~1~ through C~10~ straight chain alkanes, isobutane, hydrogen atom, hydroxyl and methyl radicals, and water were calculated between 298.15 and 1500 K using various low (semiempirical PM6) through high level (CBS-Q//B3 and G4 composite) theoretical methods. All levels of theory provided good agreement with experimental C~p,gas~ data (<+/-10% deviation) regardless of molecular size. A modest but progressive loss of C~p,gas~ predictive accuracy occurs with increasing molecular size among the n-alkanes. For most compounds at all levels of theory, the highest C~p,gas~ estimation accuracy occurs at elevated temperatures, with decreasing accuracy as the temperature is lowered or raised about the method specific accuracy maximum. In general, C~p,gas~ prediction accuracy appears to depend less on the level of theory applied compared to the temperature under consideration.
SUMO modification selectively regulates transcriptional activity of peroxisome-proliferator-activated receptor γ in C2C12 myotubes
Authors: Chung Sung Soo , Ahn Byung Yong , Kim Min , Kho Jun Ho , Jung Hye Seung , Park Kyong Soo
Published: October 2010

PPAR (peroxisome-proliferator-activated receptor) γ, a nuclear receptor, can be conjugated with SUMO (small ubiquitin-like modifier), which results in the negative regulation of its transcriptional activity. In the present study, we tested whether de-SUMOylation of PPARγ affects the expression of PPARγ target genes in mouse muscle cells and investigated the mechanism by which de-SUMOylation increases PPARγ transcriptional activity. We found that the SUMO-specific protease SENP2 [SUMO1/sentrin/SMT3 (suppressor of mif two 3 homologue 1)-specific peptidase 2] effectively de-SUMOylates PPARγ–SUMO conjugates. Overexpression of SENP2 in C2C12 cells increased the expression of some PPARγ target genes, such as FABP3 (fatty-acid-binding protein 3) and CD36 (fatty acid translocase), both in the absence and presence of rosiglitazone. In contrast, overexpression of SENP2 did not affect the expression of another PPARγ target gene ADRP (adipose differentiation-related protein). De-SUMOylation of PPARγ increased ChIP (chromatin immunoprecipitation) of both a recombinant PPRE (PPAR-response element) and endogenous PPREs of the target genes CD36 and FABP3, but ChIP of the PPRE in the ADRP promoter was not affected by SENP2 overexpression. In conclusion, these results indicate that SENP2 de-SUMOylates PPARγ in myotubes, and de-SUMOylation of PPARγ selectively increases the expression of some PPARγ target genes.
Mesohaem substitution reveals how haem electronic properties can influence the kinetic and catalytic parameters of neuronal NO synthase
Authors: Tejero Jesús , Biswas Ashis , Haque Mohammad Mahfuzul , Wang Zhi-Qiang , Hemann Craig , Varnado Cornelius L. , Novince Zachary , Hille Russ , Goodwin Douglas C. , Stuehr Dennis J.
Published: October 2010

NOSs (NO synthases, EC 1.14.13.39) are haem-thiolate enzymes that catalyse a two-step oxidation of L-arginine to generate NO. The structural and electronic features that regulate their NO synthesis activity are incompletely understood. To investigate how haem electronics govern the catalytic properties of NOS, we utilized a bacterial haem transporter protein to overexpress a mesohaem-containing nNOS (neuronal NOS) and characterized the enzyme using a variety of techniques. Mesohaem-nNOS catalysed NO synthesis and retained a coupled NADPH consumption much like the wild-type enzyme. However, mesohaem-nNOS had a decreased rate of Fe(III) haem reduction and had increased rates for haem–dioxy transformation, Fe(III) haem–NO dissociation and Fe(II) haem–NO reaction with O2. These changes are largely related to the 48 mV decrease in haem midpoint potential that we measured for the bound mesohaem cofactor. Mesohaem nNOS displayed a significantly lower Vmax and KmO2 value for its NO synthesis activity compared with wild-type nNOS. Computer simulation showed that these altered catalytic behaviours of mesohaem-nNOS are consistent with the changes in the kinetic parameters. Taken together, the results of the present study reveal that several key kinetic parameters are sensitive to changes in haem electronics in nNOS, and show how these changes combine to alter its catalytic behaviour.
Feeding Difficulties in Children With Eosinophilic Esophagitis
Authors: Furuta Glenn T. , Maune Nancy Creskoff , Haas Angela
Published: October 2010

Eosinophilic esophagitis (EoE) is a recently recognized inflammatory disease that is characterized by upper intestinal symptoms and dense eosinophilia of the esophageal mucosa. Food refusal, dysphagia, and reduced volume and variety of intake are common symptoms associated with eosinophilic esophagitis in children (Furuta et al., 2007; Spergel, 2007). Accurate diagnosis of eosinophilic esophagitis is frequently missed as many of its features are similar to other gastrointestinal diseases (Aceves, Furuta, & Spechler, 2008). Oftentimes, before this diagnosis is made, a feeding specialist is the first contact for these children in response to their eating difficulties. Gastroenterologists, allergists, feeding specialists, dietitians, psychologists, and social workers are now collaborating to provide integrated, comprehensive care for optimal diagnosis and treatment of children with eosinophilic esophagitis. In the general population, feeding difficulties are present in 25% of typically developing children and in 75-80% of children with developmental disabilities (Eicher, 1997; Iwata, Riordan, Wohl, & Finney, 1982; Kedesky & Budd, 1998; Kerwin, Ahearn, Eicher, & Burd, 1995; Lefton-Greif & Arvedson, 2007). Although prevalence numbers for feeding issues in children with eosinophilic esophagitis are unknown, it is anticipated that the prevalence will fall closer to that of children with developmental disabilities.
Preservation of Permo–Triassic low‐pressure assemblages in the Cretaceous high‐pressure metamorphic Saualpe crystalline basement (Eastern Alps, Austria)
Authors: Habler G. , Thöni M.
Published: October 2010

Metapelites and intercalated metapegmatites of the Saualpe crystalline basement, which forms part of the Austroalpine nappe complex in the Eastern Alps, display a polyphase tectonometamorphic history. Here, we focus on the evolution that these rocks underwent prior to Cretaceous (eo‐Alpine) high‐pressure metamorphism and related penetrative deformation. Geothermobarometry on coarse‐grained porphyroclastic parageneses (garnet–biotite–muscovite–plagioclase–sillimanite–quartz), which occur as relics in kyanite–garnet, two‐mica gneiss, yielded 600 °C/0.4 GPa. Results from a corundum‐bearing lithology suggest that higher temperatures may have been reached in very restricted areas. The matrix of these rocks displays intense recrystallization during a pressure‐dominated metamorphic overprint. Microstructures and mineral chemistry indicate that this low‐pressure metamorphism was the first significant metamorphic imprint in these rocks. Mineral relics in all metapelitic rock types reflect low‐pressure conditions for this interkinematic crystallization phase.

The distribution, macroscopic and microscopic observations and the mineralogical composition of intercalated metapegmatites point to regionally elevated temperature conditions during their emplacement. Therefore, pegmatite formation is correlated with mineral formation in metapelites. Sm–Nd‐dating of magmatic garnet from the pegmatite gneiss yielded 249 ± 3 Ma, which is interpreted to represent the age of pegmatite‐emplacement and low‐pressure metamorphism in the metapelites. Since the pegmatites are overprinted by mylonitisation and high‐pressure metamorphism, this Permo–Triassic age also sets an upper age‐limit to the eclogite facies metamorphic event, which affected considerable parts of the Saualpe crystalline basement.
Palaeoproterozoic high‐T, low‐P metamorphism and dehydration melting in metapelites from the Mopunga Range, Arunta Inlier, central Australia
Authors: Scrimgeour I. , Smith J. B. , Raith J. G.
Published: October 2010

A sequence of psammitic and pelitic metasedimentary rocks from the Mopunga Range region of the Arunta Inlier, central Australia, preserves evidence for unusually low pressure (c. 3 kbar), regional‐scale, upper amphibolite and granulite facies metamorphism and partial melting. Upper amphibolite facies metapelites of the Cackleberry Metamorphics are characterised by cordierite‐andalusite‐K‐feldspar assemblages and cordierite‐bearing leucosomes with biotite‐andalusite selvages, reflecting P–T conditions of c. 3 kbar and c. 650–680 °C. Late development of a sillimanite fabric is interpreted to reflect either an anticlockwise P–T evolution, or a later independent higher‐P thermal event. Coexistence of andalusite with sillimanite in these rocks appears to reflect the sluggish kinematics of the Al2SiO5 polymorphic inversion. In the Deep Bore Metamorphics, 20 km to the east, dehydration melting reactions in granulite facies metapelites have produced migmatites with quartz‐absent sillimanite‐spinel‐cordierite melanosomes, whilst in semipelitic migmatites, discontinuous leucosomes enclose cordierite‐spinel intergrowths. Metapsammitic rocks are not migmatised, and contain garnet–orthopyroxene–cordierite–biotite–quartz assemblages. Reaction textures in the Deep Bore Metamorphics are consistent with a near‐isobaric heating‐cooling path, with peak metamorphism occurring at 2.6–4.0 kbar and c. 750–800 °C. SHRIMP U–Pb dating of metamorphic zircon rims in a cordierite‐orthopyroxene migmatite from the Deep Bore Metamorphics yielded an age of 1730 ± 7 Ma, whilst detrital zircon cores define a homogeneous population at 1805 ± 7 Ma. The 1730 Ma age is interpreted to reflect the timing of high‐T, low‐P metamorphism, synchronous with the regional Late Strangways Event, whereas the 1805 Ma age provides a maximum age of deposition for the sedimentary precursor. The Mopunga Range region forms part of a more extensive low‐pressure metamorphic terrane in which lateral temperature gradients are likely to have been induced by localised advection of heat by granitic and mafic intrusions. The near‐isobaric Palaeoproterozoic P–T–t evolution of the Mopunga Range region is consistent with a relatively transient thermal event, due to advective processes that occurred synchronous with the regional Late Strangways tectonothermal event.
Tectono‐metamorphic evolution of the Karakorum Metamorphic complex (Dassu–Askole area, NE Pakistan): exhumation of mid‐crustal HT–MPgneisses in a convergent context
Authors: Rolland Y. , Mahéo G. , Guillot S. , Pecher A.
Published: October 2010

The South Karakorum margin, east of the Himalayan syntaxis, consist of an E–W elongated zone of young (10–3 Ma) high‐grade metamorphic rocks (M2) and related migmatitic domes. This late tectono‐metamorphic event post‐dates the Palaeogene (55–37 Ma) phase of thickening of the belt featured by NW–SE structures and associated M1 amphibolite facies metamorphism (0.7 GPa, 700 °C). This M2 metamorphism is characterised by low‐pressure, high‐temperature conditions coeval with migmatite formation in response to a thermal increase ofc. 150 °C compared to M1, culminating at a temperature ofc. 770 °C and a pressure of 0.5–0.6 GPa. Rapid exhumation of migmatitic domes, at a rate of 5 mm yr−1, was accommodated by vertical extrusion, in the core of E–W crustal‐scale folds. These crustal‐scale folds formed in response to N–S syn‐collisional shortening and were enhanced by thermal weakening of the migmatised continental crust.

M2 metamorphism is spatially and temporarily associated with granitoids showing a mantle affinity, firmly suggesting that this could be the advective heat source for the granite and syenite generation and the subsequent migmatisation of the mid‐crustal level. Such relationships between a mantle‐related magmatism and a high‐temperature metamorphism in a convergent shortening context are suggestive of the breakoff of the subducted Indian slab since 20 Ma.
High‐grade metamorphism and hydrous melting of metapelites in the Pinos terrane (W Cuba): Evidence for crustal thickening and extension in the northern Caribbean collisional belt
Authors: García‐Casco A. , Torres‐Roldán R. L. , Millán G. , Monié P. , Haissen F.
Published: October 2010

The Pinos terrane (Isle of Pines, W Cuba) is a coherent metamorphic complex that probably represents a portion of the continental margin of the Yucatan Block during the Mesozoic. Within the framework of other metamorphic terranes in the Greater Antilles, the Pinos terrane is characterized by the occurrence of high‐grade kyanite‐, sillimanite‐ and andalusite‐bearing metapelites and migmatites. Assessment and modelling of phase relations in these high grade rocks indicate that they reached a peak temperature of c. 750 °C at 11–12 kbar, and then underwent strong decompression to c. 3 kbar at c. 600 °C. Decompression was contemporaneous with the main synmetamorphic deformation in the area (D2), and was accompanied by segregation of trondhjemitic partial melts formed by wet melting of metapelites. Metamorphism terminated in the Uppermost Cretaceous (68 ± 2 Ma; 40Ar/39Ar dates on biotite and muscovite). The P–T–t‐deformation relations of the high‐grade rocks suggest that crustal thickening (during collision of this portion of the Yucatan margin with the Great Volcanic Arc of the Caribbean?) was followed by decompression interpreted to reflect exhumation by extension, possibly related to the initial development of the Yucatan Basin in the uppermost Cretaceous.
New photographic techniques for clinical evaluation of acne
Authors: Rizova E , Kligman A
Published: October 2010

Clinical evaluation of acne is usually based on direct visual assessment and ordinary flash photography, both of which are compromised by viewer subjectivity. It is difficult to accurately assess individual acne lesions and to observe early response to therapy. Standard flash photography has inherent limitations owing to the physics of light; it does not permit consistent visualization of subtle cutaneous characteristics like erythema or microcomedones, and it tends to blur distinctions between active inflammatory lesions and older hyperpigmented macules.

Over the last decade there has been increasing interest in newer techniques aimed at increasing the accuracy and objectivity of acne evaluation. These include parallel‐polarized light photography, cross (or perpendicular)‐polarized light photography, videomicroscopy, and fluorescence photography. This article will review the advances of the past decade and summarize new techniques to evaluate acne lesions. Moreover, findings of a study that evaluated the course of individual acne lesions and the effects of adapalene gel 0.1% on inflammatory and non‐inflammatory acne lesions will be viewed.

In this study, the use of parallel‐polarized and cross‐polarized photography, in combination with videomicroscopy and sebum production measurement, provided objective, detailed information on the evolution of different variable acne lesions and their response to adapalene gel 0.1%. Adapalene treatment produced rapid resolution of inflammatory and non‐inflammatory lesions, and inhibited formation of new lesions. Sebum secretion rates also declined during treatment. Use of the new assessment techniques proved to be a valuable, non‐invasive and reliable method of assessing acne vulgaris and its response to treatment.
Acanthosis nigricans: A new cutaneous sign in severe atopic dermatitis and Down syndrome
Authors: Muñoz‐Pérez MA , Camacho F
Published: October 2010

Acanthosis nigricans (AN) occurs associated with many different systemic diseases, such as endocrine disorders and internal malignant neoplasms. To our knowledge, the association of AN with severe atopic dermatitis (AD) or Down syndrome has not been described before. This 82‐month retrospective study included 1038 patients: AN was present in 4.9% of atopic patients and 50.9% of subjects with Down syndrome. AN was more frequent in patients with severe AD and in 100% of cases of hand dermatitis and juvenile plantar dermatosis, located on the interphalangeal and metacarpophalangeal joints, whereas in Down syndrome other flexures were also affected. The pathogenesis of AN in AD is unknown, but in Down syndrome it seems to be related to obesity. Possible insulin resistance underlyng the pathogenesis of AN in these patients is still unknown.
Morphometric analysis of elastic skin fibres from patients with: cutis laxa, anetoderma, pseudoxanthoma elasticum, and Buschke–Ollendorff and Williams–Beuren syndromes
Authors: Ghomrasseni S , Dridi M , Bonnefoix M , Septier D , Gogly G , Pellat B , Godeau G
Published: October 2010

Computed morphometric analysis of elastic skin fibres in patients with cutis laxa, anetoderma, Williams–Beuren syndrome, pseudoxanthoma elasticum (PXE), and Buschke–Ollendorff syndrome, all clinically ascertained, was performed and compared with data obtained from healthy individuals of the same age. The diameters, area fractions (AA%) and volume fractions (VV%) occupied by pre‐elastic fibres and dermal elastic fibres were determined. Irrespective of age the diameter of dermal elastic fibres followed a Gaussian distribution for all groups studied. These diameters were taken into consideration for VV% determinations. Compared with data from skin of healthy subjects of similar age range, VV% of pre‐elastic fibres was significantly decreased in patients with cutis laxa, anetoderma, Williams–Beuren syndrome, and PXE and undetectable in Buschke–Ollendorff patients. VV% of dermal elastic fibres was four‐ to fivefold increased in Buschke–Ollendorff syndrome, two‐ to threefold increased in PXE skin, four‐ to fivefold decreased in cutis laxa and anetoderma skin and about twofold decreased in Williams–Beuren skin. The diameter of oxytalan fibres was decreased in anetoderma and Williams–Beuren syndrome while oxytalan fibre diameter was unchanged in PXE and cutis laxa. The diameter of dermal elastic fibres was increased in PXE and Buschke–Ollendorff syndrome, but was decreased in anetoderma and Williams–Beuren syndrome and unchanged in cutis laxa. We demonstrated that cutis laxa, anetoderma, Williams–Beuren syndrome, PXE, and Buschke–Ollendorff syndrome could be easily differentiated by morphometric analysis of elastic skin fibres. Thus we propose that morphometric analyses together with skin biopsies are a valuable tool for distinguishing between inherited and/or acquired skin diseases known to display alterations of elastic fibres.
Acral necrosis by Stenotrophomonas maltophilia
Authors: Pereira O , Cunha Velho G , Lopes V , Mota F , Santos C , Massa A
Published: October 2010

Background

Stenotrophomonas maltophilia (SM) has been considered a nosocomial pathogen. Nevertheless, community acquired infection may occur more frequently than usually recognized.

Case

We describe distal necrosis of the fingers by SM in a farmer, contracted in the community and successfully treated with a combination of cotrimoxazole and ciprofloxacin. The patient was diagnosed with chronic lymphocytic leukaemia 6 months later.

Conclusions

This unusual presentation shows that infection with SM should be included in the differential diagnosis of the skin and soft tissue infection, even in apparently healthy patients.
Acneiform eruption caused by amineptine. A case report and review of the literature
Authors: De Gálvez Aranda MV , Sánchez Sánchez P , Alonso Corral MJ , Bosch García RJ , Gallardo MA , Herrera Ceballos E
Published: October 2010

Acne caused by amineptine has always been described with typical characteristic clinical features, and the retentional and cutaneous lesions are dose related. We present a case of acne‐like eruption due to amineptine in a woman under treatment for chronic depression.
Vesicular prurigo pigmentosa cured by minocycline
Authors: Matsumoto C , Kinoshita M , Baba S , Suzuki H , Kanematsu S , Kanematsu N
Published: October 2010

We present a case of prurigo pigmentosa associated with vesicles that we call ‘vesicular prurigo pigmentosa’. The subject was treated using minocycline with good results and no recurrence of the lesions over a 2‐year period.
Sleep and its homeostatic regulation in mice lacking the adenosine A1receptor
Authors: Stenberg Dag , Litonius Erik , Halldner Linda , Johansson Björn , Fredholm Bertil B. , Porkka‐Heiskanen Tarja
Published: October 2010

Sleep deprivation (SD) increases extracellular adenosine levels in the basal forebrain, and pharmacological manipulations that increase extracellular adenosine in the same area promote sleep. As pharmacological evidence indicates that the effect is mediated through adenosine A1receptors (A1R), we expected A1R knockout (KO) mice to have reduced rebound sleep after SD. Male homozygous A1R KO mice, wild‐type (WT) mice, and heterozygotes (HET) from a mixed 129/C57BL background were implanted during anesthesia with electrodes for electroencephalography (EEG) and electromyography (EMG). After 1 week of recovery, they were allowed to adapt to recording leads for 2 weeks. EEG and EMG were recorded continuously. All genotypes had a pronounced diurnal sleep/wake rhythm after 2 weeks of adaptation. We then analyzed 24 h of baseline recording, 6 h of SD starting at light onset, and 42 h of recovery recording. Neither rapid eye movement sleep (REM sleep) nor non‐REM sleep (NREMS) amounts differed significantly between the groups. SD for 6 h induced a strong NREMS rebound in all three groups. NREMS time and accumulated EEG delta power were equal in WT, HET and KO. Systemic administration of the selective A1R antagonist 8‐cyclopentyltheophylline (8‐CPT) inhibited sleep for 30 min in WT, whereas saline and 8‐CPT both inhibited sleep in KO. We conclude that constitutional lack of adenosine A1R does not prevent the homeostatic regulation of sleep.