bluuebunny/crossref_metadata_2025 huggingface dataset:
Screw placement in slipped upper femoral epiphysis: Is good the enemy of better?
Authors: Jamil Wiqqas , Allami Mohamad K. , Varghese Bobin , Almaiyah Mohammed , Giannoudis Peter
Published: August 2007

Introduction and aims A single hip screw is the recommended method of fixation for slipped upper femoral epiphysis (SUFE). Current practice favours the placement of the screw in the centre of the femoral head on both anteroposterior and lateral planes to avoid the risks of chondrolysis and avascular necrosis (AVN). We investigated the correlation between different positions of the screw in the femoral head and the prevalence of AVN, chondrolysis, late slippage and the time to epiphyseal closure.

Methods The clinical notes and radiographs of 38 consecutive patients (61 hips) who underwent single screw fixation for SUFE were evaluated retrospectively with a mean follow-up of 36 months. Two-way ANOVA and the post hoc test was performed to analyse the correlation between the different variables and the outcome at the 5% level of significance.

Results There were 16 acute slips, 18 chronic slips and ten acute-on-chronic slips. Seventeen slips were treated prophylactically. Mild slip was encountered in 39 hips, moderate slip in four and severe slip in one. The central–central position was only achieved in 51% of cases. The most significant results of the study were as follows: (1) no significant difference between the time to epiphyseal closure and the position of the screw, and (2) no late slippage or chondrolysis was observed in our series.

Conclusion Our results showed that the positioning of the screw other than in the centre of the femoral head has the ability to provide physeal stability and has no correlation with the timing to closure of the epiphysis and the risk of avascular necrosis or chondrolysis. We therefore recommend that other positions be considered if the “optimal central–central position” is not initially achieved – specifically for the treatment of mild slip – as the potential hazards from several attempts to achieve the optimum position outweigh the benefits.
Stimulus interval, rate and direction differentially regulate phosphorylation for mechanotransduction in neonatal cardiac myocytes
Authors: Senyo Samuel E. , Koshman Yevgeniya E. , Russell Brenda
Published: August 2007

The effect of interval, direction and rate of strain on mechanotransduction in neonatal rat cardiomyocytes is determined for focal adhesion kinase (Y397pFAK), extracellular signal‐regulated kinase ERK1/2 (Thr183/Tyr185) and paxillin (pY31) and phosphorylation time courses to 10% strain assessed. Cells are non‐responsive at 5 min but recover at 15 min (P
< 0.03) with FAK nuclear translocation by 30 min. Cyclic biaxial strain increased phosphorylation from slower to faster rates (P
< 0.05). Uniaxial strain to groove‐aligned myocytes increased FAK and ERK1/2 phosphorylation transversely more than longitudinally (P
< 0.05). Mechanotransduction may have a refractory period of 5 min and differentiate directions and rates of strain.
Cardiac mitochondrial ATP‐sensitive potassium channel is activated by nitric oxide in vitro
Authors: Ljubkovic Marko , Shi Yang , Cheng Qunli , Bosnjak Zeljko , Jiang Ming Tao
Published: August 2007

Previous observations on the activation of the mitochondrial ATP‐sensitive potassium channel (mitoKATP) by nitric oxide (NO) in myocardial preconditioning were based on indirect evidence. In this study, we have investigated the direct effect of NO on the rat cardiac mitoKATP after reconstitution of the inner mitochondrial membranes into lipid bilayers. We found that the mitoKATP was activated by exogenous NO donor S‐nitroso‐N‐acetyl penicillamine or PAPA NONOate. This activation was inhibited by mitoKATP blockers 5‐hydroxydecanoate or glibenclamide. Our observations confirm that NO can directly activate the cardiac mitoKATP, which may underlie its contribution to myocardial preconditioning.
ON AN OPEN QUESTION OF RICCERI CONCERNING A NEUMANN PROBLEM
Authors: FARACI FRANCESCA , KRISTÁLY ALEXANDRU
Published: August 2007

In this paper we solve partially an open problem raised by B. Ricceri (Bull. London Math. Soc.33 (2001), 331–340). Infinitely many solutions for a Neumann problem are obtained through a direct variational approach where the nonlinearity has an oscillatory behaviour at infinity.
NOTE ON A PAPER OF J. HOFFSTEIN
Authors: PATTERSON S. J.
Published: August 2007

The concept of a metaplectic form was introduced about 40 years ago by T. Kubota. He showed how Jacobi-Legendre symbols of arbitrary order give rise to characters of arithmetic groups. Metaplectic forms are the automorphic forms with these characters. Kubota also showed how higher analogues of the classical theta functions could be constructed using Selberg's theory of Eisenstein series. Unfortunately many aspects of these generalized theta series are still unknown, for example, their Fourier coefficients. The analogues in the case of function fields over finite fields can in principle be calculated explicitly and this was done first by J. Hoffstein in the case of a rational function field. Here we shall return to his calculations and clarify a number of aspects of them, some of which are important for recent developments.
PROPERTIES OF CERTAIN SUBALGEBRAS OF DALES-DAVIE ALGEBRAS
Authors: ABTAHI M. , HONARY T. G.
Published: August 2007

We study an interesting class of Banach function algebras of infinitely differentiable functions on perfect, compact plane sets. These algebras were introduced by H. G. Dales and A. M. Davie in 1973, called Dales-Davie algebras and denoted by D(X, M), where X is a perfect, compact plane set and M = {Mn}∞n = 0 is a sequence of positive numbers such that M0 = 1 and (m + n)!/Mm+n ≤ (m!/Mm)(n!/Mn) for m, n ∈ N. Let d = lim sup(n!/Mn)1/n and Xd = {z ∈ C : dist(z, X) ≤ d}. We show that, under certain conditions on X, every f ∈ D(X, M) has an analytic extension to Xd. Let DP [DR]) be the subalgebra of all f ∈ D(X, M) that can be approximated by the restriction to X of polynomials [rational functions with poles off X]. We show that the maximal ideal space of DP is $X^_d$, the polynomial convex hull of Xd, and the maximal ideal space of DR is Xd. Using some formulae from combinatorial analysis, we find the maximal ideal space of certain subalgebras of Dales-Davie algebras.
POSITIVE SOLUTIONS FOR ASYMPTOTICALLY LINEAR ELLIPTIC SYSTEMS
Authors: PENG CHAOQUAN , YANG JIANFU
Published: August 2007

In this paper, we show that the semilinear elliptic systems of the form
(0.1)
possess at least one positive solution pair (u, v) ∈ H10(Ω) × H10(Ω), where Ω is a smooth bounded domain in $\mathbb{R}^N$, f(x,t) and g(x, t) are continuous functions on $\Omega\times \mathbb{R}$ and asymptotically linear at infinity.
HARDY–BLOCH TYPE SPACES AND LACUNARY SERIES ON THE POLYDISK
Authors: AVETISYAN K. L.
Published: August 2007

We extend the well-known Paley and Paley-Kahane-Khintchine inequalities on lacunary series to the unit polydisk of $\C^n$. Then we apply them to obtain sharp estimates for the mean growth in weighted spaces h(p, α), h(p, log(α)) of Hardy–Bloch type, consisting of functions n-harmonic in the polydisk. These spaces are closely related to the Bloch and mixed norm spaces and naturally arise as images under some fractional operators.
SAMELSON PRODUCTS OF SO(3) AND APPLICATIONS
Authors: KAMIYAMA YASUHIKO , KISHIMOTO DAISUKE , KONO AKIRA , TSUKUDA SHUICHI
Published: August 2007

Certain generalized Samelson products of SO(3) are calculated and applications to the homotopy of gauge groups are given.
MORSE INEQUALITIES ON CERTAIN INFINITE 2-COMPLEXES
Authors: AYALA R. , FERNÁNDEZ L. M. , VILCHES J. A.
Published: August 2007

Using the notion of discrete Morse function introduced by R. Forman for finite cw-complexes, we generalize it to the infinite 2-dimensional case in order to get the corresponding version of the well-known discrete Morse inequalities on a non-compact triangulated 2-manifold without boundary and with finite homology. We also extend them for the more general case of a non-compact triangulated 2-pseudo-manifold with a finite number of critical simplices and finite homology.
ON THE SQUARE-FREE PARTS OF ⌊en!⌋
Authors: LUCA FLORIAN , SHPARLINSKI IGOR E.
Published: August 2007

In this note, we show that if we write ⌊en!⌋ = s(n)u(n)2, where s(n) is square-free then

has at least C log log N distinct prime factors for some absolute constant C > 0 and sufficiently large N. A similar result is obtained for the total number of distinct primes dividing the mth power-free part of s(n) as n ranges from 1 to N, where m ≥ 3 is a positive integer. As an application of such results, we give an upper bound on the number of n ≤ N such that ⌊en!⌋ is a square.
Assessment of Several Interpolation Methods for Precise GPS Orbit
Authors: Yousif Hamad , El-Rabbany Ahmed
Published: August 2007

GPS applications such as Precise Point Positioning (PPP) require the availability of precise ephemeris at high rate. To support these applications, several institutions such as the International GNSS Service (IGS) have developed precise orbital service. Unfortunately, however, the data rate of such precise orbits is usually limited to 15 minutes. To overcome this problem, a number of orbital interpolation methods are proposed. This paper examines the performance of four interpolation methods for IGS precise GPS orbits, namely Lagrange, Newton Divided Difference, Cubic Spline and Trigonometric interpolation. In addition, the paper discusses a new approach, which utilizes the residuals between the broadcast and precise ephemeris to generate a high density precise ephemeris. It is shown that the new approach produces better results than previously reported orbital interpolation accuracy.
SBAS Algorithm Performance in the Implementation of the ASIAPACIFIC GNSS Test Bed
Authors: Pringvanich Noppadol , Satirapod Chalermchon
Published: August 2007

This paper discusses the preliminary performance analysis result of the Asia-Pacific Global Navigation Satellite Systems (GNSS) Test Bed. Currently, seven Asia-Pacific economies are participating in the Test Bed project, namely Australia, Chinese Taipei, Indonesia, Malaysia, the Philippines, Thailand and Vietnam. The Test Bed was commissioned in May 2006. The discussion topics in this paper include Test Bed system architecture and preliminary analysis of the system performance. As presented in this paper, while current Satellite-Based Augmentation System (SBAS) algorithms can improve the accuracy performance of GPS positioning results, it cannot fulfill the integrity performance required by civil aviation community. This paper analyzes the limitation of the algorithm and proposes future research topics related to the limitation.
Improving Adaptive Kalman Estimation in GPS/INS Integration
Authors: Ding Weidong , Wang Jinling , Rizos Chris , Kinlyside Doug
Published: August 2007

The central task of GPS/INS integration is to effectively blend GPS and INS data together to generate an optimal solution. The present data fusion algorithms, which are mostly based on Kalman filtering (KF), have several limitations. One of those limitations is the stringent requirement on precise a priori knowledge of the system models and noise properties. Uncertainty in the covariance parameters of the process noise (Q) and the observation errors (R) may significantly degrade the filtering performance. The conventional way of determining Q and R relies on intensive analysis of empirical data. However, the noise levels may change in different applications. Over the past few decades adaptive KF algorithms have been intensively investigated with a view to reducing the influence of the Q and R definition errors. The covariance matching method has been shown to be one of the most promising techniques. This paper first investigates the utilization of an online stochastic modelling algorithm with regards to its parameter estimation stability, convergence, optimal window size, and the interaction between Q and R estimations. Then a new adaptive process noise scaling algorithm is proposed. Without artificial or empirical parameters being used, the proposed adaptive mechanism has demonstrated the capability of autonomously tuning the process noise covariance to the optimal magnitude, and hence improving the overall filtering performance.
A Difference Test Method for Early Detection of Slowly Growing Errors in GNSS Positioning
Authors: Feng Shaojun , Ochieng Washington
Published: August 2007

Satellite based navigation system integrity monitoring is essential both for liability and safety critical services. The threats to system integrity are the potential failure modes that could occur at system, operational and user sensor levels. Research on identification, characterisation and modelling of such failure modes, suggests that failures that grow slowly over time (e.g. ramp error less than 2 m/s), also referred to as slowly growing errors (SGE) are the most difficult to detect early. Conventional snapshot algorithms detect SGEs when the test statistic crosses the threshold usually after relatively long periods of time. A recent concept based on the average of residuals over time has been found to have a significant weakness. This paper proposes a “difference test” algorithm capable of detecting SGEs early. In this method, the test statistic is the difference between the norm of current residuals and the norm of the residuals at a previous epoch. The distribution of the test statistic is over-bounded by a normal distribution whose parameters are derived from two Chi-distributions. Results show that the new algorithm results in a significant reduction in detection time compared to conventional methods.
Investigations into Phase Multipath Mitigation Techniques for High Precision Positioning in Difficult Environments
Authors: Lau Lawrence , Cross Paul
Published: August 2007

The modelling of most Global Navigation Satellite System (GNSS) errors/biases and developments of data processing techniques have been improved substantially since the birth of Global Positioning System (GPS), however, there has been much less progress in the improvement of phase multipath mitigation techniques. Multipath therefore remains one of the most important error sources in high precision GNSS positioning. This is because multipath is site-dependent and therefore cannot be eliminated by differencing techniques. Also multipath is highly dependent on satellite-reflector-antenna geometry, which usually causes rapid changes in phase multipath errors especially in Real-Time Kinematic (RTK) applications. Multipath mitigation for static antennas such as those at reference stations can be carried out by site calibration, averaging over long observation times, and through the estimation of the error using filtering based on signal-to-noise ratio (SNR) data. However, multipath mitigation for kinematic antennas is still very difficult today.

Nevertheless, much research has been carried out on a particular class of phase multipath mitigation techniques: ones that can be applied within positioning algorithms (rather than incorporated into the receiver tracking loops or antennas). This paper investigates and further develops a number of state-of-the-art techniques in this category. They include phase multipath estimation using SNR data, phase multipath estimation through the use of closely spaced antennas, multipath mitigation stochastic models such as the satellite elevation angle model and SNR-based models (SIGMA-∊ model and our modified SNR-based model), and our own novel ray-tracing method. The techniques are tested with both real and simulated data, the real test datasets have been collected on the Laboratoire Central des Ponts et Chaussées (LCPC) testbed near Nantes in France, and on the campus of the University of Nottingham during SPACE data collection experiments.
Part II. Analysis of data gaps pertaining toShigellainfections in low and medium human development index countries, 1984–2005
Authors: RAM P. K. , CRUMP J. A. , GUPTA S. K. , MILLER M. A. , MINTZ E. D.
Published: August 2007

The global incidence ofShigellainfection has been estimated at 80–165 million episodes annually, with 99% of episodes occurring in the developing world. To identify contemporary gaps in the understanding of the global epidemiology of shigellosis, we conducted a review of the English-language scientific literature from 1984 to 2005, restricting the search to low and medium human development countries. Our review yielded 11 population-based studies ofShigellaburden from seven countries. No population-based studies have been conducted in sub-Saharan Africa or in low human development countries. In studies done in all age groups,Shigellaincidence varied from 0·6 to 107 episodes/1000 person-years.S. flexneriwas the most commonly detected subgroup in the majority of studies. Case-fatality rates ranged from 0% to 2·6% in population-based studies and from 0% to 21% in facility-based studies. This review highlights the large gaps in data on the burden ofShigellainfections for low human development index countries and, more specifically, for sub-Saharan Africa.
Temporal properties of surround suppression in cat primary visual cortex
Authors: DURAND SÉVERINE , FREEMAN TOBE C.B. , CARANDINI MATTEO
Published: August 2007

The responses of neurons in primary visual cortex (V1) are suppressed by stimuli presented in the region surrounding the receptive field. There is debate as to whether this surround suppression is due to intracortical inhibition, is inherited from lateral geniculate nucleus (LGN), or is due to a combination of these factors. The mechanisms involved in surround suppression may differ from those involved in suppression within the receptive field, which is called cross-orientation suppression. To compare surround suppression to cross-orientation suppression, and to help elucidate its underlying mechanisms, we studied its temporal properties in anesthetized and paralyzed cats. We first measured the temporal resolution of suppression. While cat LGN neurons respond vigorously to drift rates up to 30 Hz, most cat V1 neurons stop responding above 10–15 Hz. If suppression originated in cortical responses, therefore, it should disappear above such drift rates. In a majority of cells, surround suppression decreased substantially when surround drift rate was above ∼15 Hz, but some neurons demonstrated suppression with surround drift rates as high as 21 Hz. We then measured the susceptibility of suppression to contrast adaptation. Contrast adaptation reduces responses of cortical neurons much more than those of LGN neurons. If suppression originated in cortical responses, therefore, it should be reduced by adaptation. Consistent with this hypothesis, we found that prolonged exposure to the surround stimulus decreased the strength of surround suppression. The results of both experiments differ markedly from those previously obtained in a study of cross-orientation suppression, whose temporal properties were found to resemble those of LGN neurons. Our results provide further evidence that these two forms of suppression are due to different mechanisms. Surround suppression can be explained by a mixture of thalamic and cortical influences. It could also arise entirely from intracortical inhibition, but only if inhibitory neurons respond to somewhat higher drift rates than most cortical cells.
Psychosocial and demographic predictors of fruit, juice and vegetable consumption among 11–14-year-old Boy Scouts
Authors: Gallaway M Shayne , Jago Russell , Baranowski Tom , Baranowski Janice C , Diamond Pamela M
Published: August 2007

Objective

Psychosocial and demographic correlates of fruit, juice and vegetable (FJV) consumption were investigated to guide how to increase FJV intake.

Design

Hierarchical multiple regression analysis of FJV consumption on demographics and psychosocial variables.

Setting

Houston, Texas, USA.

Subjects

Boys aged 11–14 years (n= 473).

Results

FJV preference and availability were both significant predictors of FJV consumption, controlling for demographics and clustering of Boy Scout troops. Vegetable self-efficacy was associated with vegetable consumption. The interaction of preference by home availability was a significant predictor of FJV. The interaction of self-efficacy by home availability showed a trend towards significantly predicting vegetable consumption. No significant interactions were found between body mass index and the psychosocial variables.

Conclusions

Findings suggest that future interventions emphasising an increase in preference, availability and efficacy may increase consumption of FJV in similar populations.
Effects of meat consumption and vegetarian diet on risk of wrist fracture over 25 years in a cohort of peri- and postmenopausal women
Authors: Thorpe Donna L , Knutsen Synnove F , Lawrence Beeson W , Rajaram Sujatha , Fraser Gary E
Published: August 2007

Background

Evidence suggesting that a diet high in fruits and vegetables may be beneficial to bone health has sparked interest in the potential benefit of a vegetarian diet. However, other studies have raised a question regarding the adequacy of protein in such a diet.

Objective

The aim of the present study was to take a whole foods approach in examining the effects of foods high in protein on the risk of wrist fracture (WF) in a cohort with a significant proportion consuming a meat-free diet.

Design

A cohort study of women who completed two lifestyle surveys 25 years apart.

Subjects

One thousand eight hundred and sixty-five peri- and postmenopausal women at the time of the first survey.

Results

There was a significant interaction between meat consumption and foods high in vegetable protein. Among vegetarians, those who consumed the least vegetable protein intake were at highest risk for fracture. However, increasing levels of plant-based high-protein foods decreased WF risk, with a 68% reduction in risk (hazard ratio (HR) = 0.32, 95% confidence interval (CI) 0.13–0.79) in the highest intake group. Among those with lowest vegetable protein consumption, increasing meat intake decreased the risk of WF, with the highest consumption decreasing risk by 80% (HR = 0.20, 95% CI 0.06–0.66).

Conclusions

The finding that higher consumption frequencies of foods rich in protein were associated with reduced WF supports the importance of adequate protein for bone health. The similarity in risk reduction by vegetable protein foods compared with meat intake suggests that adequate protein intake is attainable in a vegetarian diet.
Does interview mode matter for food security measurement? Telephone versus in-person interviews in the Current Population Survey Food Security Supplement
Authors: Nord Mark , Hopwood Heather
Published: August 2007

Objective

To assess whether interview mode (telephone vs. in-person) affects the results of surveys that measure food security.

Design

Responses given by households interviewed by telephone and in-person in recent US Current Population Survey Food Security Supplements (CPS-FSS) were compared. Statistical methods based on the Rasch measurement model were used to assess whether response patterns differed between the two interview modes. Multivariate logistic regression analysis was then used to gauge the effect of interview mode on the measured household prevalence rates of food insecurity and very low food security while controlling for income, employment, household structure, and other household characteristics that affect food security.

Results

Response patterns to the indicators that comprise the food security scale did not differ substantially between interview modes. Prevalence rates of food insecurity and very low food security estimated from the two interview modes differed by only small proportions after accounting for differences in the socio-economic characteristics of households.

Conclusions

Findings suggest that effects of interview mode on food security measurement in the CPS-FSS are small, or at most modest. Prevalence estimates may be biased upwards somewhat for households interviewed in-person compared with those interviewed by telephone. The extent to which these results can be generalised may depend, to some extent, on survey characteristics other than interview mode, such as surveyor name recognition and respondents’ trust and confidence in the surveyor.
Congenital myasthenic syndromes: spotlight on genetic defects of neuromuscular transmission
Authors: Müller Juliane S , Mihaylova Violeta , Abicht Angela , Lochmüller Hanns
Published: August 2007

The neuromuscular junction (NMJ) is a complex structure that efficiently communicates the electrical impulse from the motor neuron to the skeletal muscle to induce muscle contraction. Genetic and autoimmune disorders known to compromise neuromuscular transmission are providing further insights into the complexities of NMJ function. Congenital myasthenic syndromes (CMSs) are a genetically and phenotypically heterogeneous group of rare hereditary disorders affecting neuromuscular transmission. The understanding of the molecular basis of the different types of CMSs has evolved rapidly in recent years. Mutations were first identified in the subunits of the nicotinic acetylcholine receptor (AChR), but now mutations in ten different genes – encoding post-, pre- or synaptic proteins – are known to cause CMSs. Pathogenic mechanisms leading to an impaired neuromuscular transmission modify AChRs or endplate structure or lead to decreased acetylcholine synthesis and release. However, the genetic background of many CMS forms is still unresolved. A precise molecular classification of CMS type is of paramount importance for the diagnosis, counselling and therapy of a patient, as different drugs may be beneficial or deleterious depending on the molecular background of the particular CMS.
Low-Mass Eclipsing Binaries to Refine Barnes-Evans–Like Relations
Authors: Amado Pedro J.
Published: August 2007

The relation of the surface brightness, a parameter related to the apparent magnitude and the angular diameter of a star, with a colour index is used to determine various stellar parameters. Eclipsing spectroscopic binaries can even be used as a distance indicator. In this work, we use a number of low-mass eclipsing binaries, whose parameters have been accurately determined, to refine the Barnes-Evans–like relation FV − (Ic − K) introduced by Amado et al. (1999), a relation more suitable for the low temperature of these cool stars.
RR Lyrae in M15: Fourier Decomposition and Physical Parameters
Authors: Lugo G. García , Ferro A. Arellano , Rosenzweig Patricia
Published: August 2007

The V and R light curves for 30 RR Lyrae stars in M15 were used to calculate their physical parameters. The Blazhko effect, previously reported in V12, was not detected. The determined values of the iron content and distance of the cluster are: [Fe/H] = −1.98 ± 0.24 and d = 8.67 ± 0.41 kpc, respectively. The mean values of the physical parameters determined for the RR Lyrae stars place the cluster precisely into the sequences Oosterhoff type – metallicity and metallicity – effective temperature, valid for globular clusters.
Eta Carinae: an Astrophysical Laboratory
Authors: Gull T.R. , Nielsen K.E. , Corcoran M.F. , Hillier D.J. , Hamaguchi K.
Published: August 2007

Eta Carinae (ηCar), a Luminous Blue Variable, is a massive binary star system with a 5.54-year spectroscopic period. We present temporal surface plots of selected He I, H I, Fe II and [N II] stellar line profiles measured with HST/STIS sampled from 1998.0 to 2004.3. Our analysis suggests that the profile variations are due to 1) radial velocity variations of the primary star and 2) ionization effects due to the hot companion combined with its wind cavity.
An Optical Search for Dwarf Novae in M22
Authors: Hourihane A.P. , Callanan P.J. , Cool A.M.
Published: August 2007

We report on the results of our 2004 monitoring program of M22, designed to search for CVs undergoing dwarf nova (DN) eruptions. We wish to compare these globular cluster systems to similar ones in the field and determine if their different formation mechanisms result in different properties. We present a light curve for a CV candidate that went into outburst during May. Data were reduced with the ISIS image subtraction routine. Our ground-based results are consistent with previous HST measurements, and confirm the DN nature of the outburst. We also report on further attempts to apply the ISIS software to look for additional outbursts of this object during 2004 as well as to identify other variable candidates in the core of M22.
Properties of Circumstellar Dust in Symbiotic Miras
Authors: Kotnik-Karuza D. , Jurkic T. , Friedjung M.
Published: August 2007

We present a study of the properties of circumstellar dust in symbiotic Miras during sufficiently long time intervals of minimal obscuration. The publishedJHKLmagnitudes of o Ceti, RX Pup, KM Vel, V366 Car, V835 Cen, RR Tel and R Aqr have been collected. In order to investigate their long-term variations, we removed the Mira pulsations to correct their light curves. Assuming spherical temperature distribution of the dust in the close neighbourhood of the Mira, the DUSTY code was used to solve the radiative transfer in order to determine the dust temperature and its properties in each particular case.

The preliminary results of this systematic study of dust envelopes in symbiotic stars with Miras as cool components provide information on nature of dust in these objects.
Orbits of Post-AGB Stars with Dusty Discs
Authors: Evans T. Lloyd , Van Winckel H.
Published: August 2007

Optical photometry and radial velocities have been obtained for stars whose near- and mid-infrared colours suggest that they have dusty circumstellar discs; many are RV Tauri variables. A subset of six stars have earlier spectral types and smaller light amplitudes than classical RV Tauri stars. All are spectroscopic binaries, with surprisingly short periods.
Surface Imaging of Late-Type Contact Binaries II: Hα Emission in AE Phe and YY Eri
Authors: Vilhu O. , Maceroni C.
Published: August 2007

We present and discuss the Hα (λ = 6563Å) observations of the contact (W UMa type) binaries AE Phoenicis and YY Eridani, obtained in 1989, 1990 and 1995 with the CAT/CES telescope of the Southern European Observatory (ESO). In particular, we compare the intrinsic equivalent widths of both components with the NextGen theoretical models and the saturation limit. We find that the average Hα equivalent widths are close to the saturation border and that the primary components have excess Hα-emission, indicating enhanced chromospheric activity. This is compatible with both theoretical and observational suggestions that the primary is the more magnetically active component and is filled with (mostly unresolvable) dark spots and associated chromospheric plages.
The Orbit of the Visual Binary ADS 8630
Authors: Scardia Marco , Argyle Robert , Prieur Jean-Louis , Pansecchi Luigi , Basso Stefano , Law Nicholas , Mackay Craig
Published: August 2007

Using the 35 speckle measurements performed with PISCO in Merate between 2004 and 2006, and some complementary new astrometric measures, we present a new orbit for the visual binary ADS 8630 = γ Vir. This new series of measurements was essential for constraining the 169 year-period orbit since it covers an arc of 130° in the apparent orbit and includes the periastron passage of 2005.
QPOs in Microquasars: the Spin Problem
Authors: Török Gabriel , Abramowicz Marek A. , Stuchlík Zdeněk , Šrámková Eva
Published: August 2007

In Galactic microquasars with double-peak kHz quasi-periodic oscillations (QPOs), the ratio of the two frequencies is 3:2. This supports the suggestion that double-peak kHz QPOs are due to a non-linear resonance between two modes of accretion disk oscillations. For the microquasars with known mass, we briefly compare the black hole spin estimates based on the orbital resonance model with the recently reported spin predictions obtained by fitting the spectral continua. Results of these two approaches are not in good agreement. We stress that if the spectral fit estimates are accurate and can be taken as referential (which is still questionable), the disagreement between the predicted and referential values would represent a rather generic problem for any relativistic QPO model, as no spin influence would appear in the observed 1/Mscaling of the QPO frequencies. The epicyclic frequencies relevant in these models are often considered to be equal to those of a test particle motion. However modifications of the frequencies due to disc pressure or other non-geodesic effects may play an important role, and the inaccuracy introduced in the spin estimates by the test particle approximation could be crucial.
An Expanded Bandpass List for Atmospheric Emission in Eclipsing Binary Models
Authors: Hamme Walter Van , Wilson R.E.
Published: August 2007

Programs for modeling binary star observables compute emergent intensity for given composition as it varies with local effective temperature, local gravity, and direction. With arrival of huge data sets from Gaia and other surveys, the benefits of fast, compact, and accurate computation of atmospheric radiation is likely to remain critical for the foreseeable future. Experience has shown that accurate radiative modeling is important for good parameter estimation. Here we augment the radiative treatment by Van Hamme & Wilson (2003) with a procedure by which individuals can generate the needed Legendre coefficients for arbitrary photometric bands. Resulting files can be inserted directly into the Wilson-Devinney (W-D) program without sacrificing portability or program unity, and should easily be adaptable to other binary star programs. We expect the new bandpass options to become part of the public W-D program. Limb-darkening tables will be placed at http://www.fiu.edu/~vanhamme/limdark.htm.
A Potentially Stabilizing Magnetic Effect in Astrophysical Jets
Authors: Viallet M. , Baty H.
Published: August 2007

We investigate the development of Kelvin-Helmholtz instabilities in magnetized jets by means of high-resolution spatial simulations. Our main finding is the existence of a stabilizing mechanism driven by the initial disruption of the jet. This mechanism gives rise to a local amplification of the magnetic field, which in turn leads to an enhanced stability of the jet configuration.
Astronomy for teachers in Mexico
Authors: Fierro Julieta
Published: August 2007

In this paper I shall present ways in which professional astronomers in developing nations can aid basic education by using a few things that have been done in Mexico.

Recently the compulsory education in Mexico was increased from 6 to 12 years. An optional subject on astronomy was included in high school; so there are several ways in which one can contribute to the national education system.

I shall give a practical example on ways to teach and mention the importance of magazines and books dedicated to teachers. I will also address the way we have implemented brief courses for educators and organized conferences for science teachers.

It is important to emphasize that we must find ways to train people in a more effective way.
Encounters with Science at ULA, Venezuela: an incentive for learning
Authors: Rosenzweig Patricia , Escalona O. , Guzmán E. , Bocaranda P. , Echeverría R. , Naranjo O.
Published: August 2007

In the School of Science of the Universidad de Los Andes (ULA), in Mérida, Venezuela, a very successful event focused on elementary and high school students, was founded in 2000. The name of this event is “Encounter with Physics, Chemistry, Mathematics, and Biology” (hereinafter “Encounters with Science”), and it integrates these disciplines, as well as Astronomy. Its main purpose is that young minds can become familiar with the methods of science inquiry and reasoning, and can understand the concepts and processes of the sciences through thoroughly prepared experiences.

“Encounters with Science” has grown each year in an exponential way. As a matter of fact, in its sixth edition (2005), the number of elementary and high school students coming from all over the country, has reached the outstanding number of approximately nine thousand. Among all the experiences that the students could be engaged in, were many involving Astronomy. These experiences were prepared by professors, together with graduate and undergraduate students, who are pursuing their degrees in all branches of science, including Astronomy. Although there is this incredible team of faculties and graduate and undergraduate students working together; the target is the students of the high and elementary schools. We certainly focus on the engaging and encouraging of students to experience scientific work at first hand.

This flourishing program is continuing to grow and to become strong. It has matured in the sense that now our professors have prepared an excellent didactic material that can, together with the hour/class teaching, prepare high school and elementary school students for a better understanding of science; particularly, helping in this way for a better education in Astronomy.

The main event of the Encounters lasts five days in the School of Science of ULA, but subsidiary events are spread all over the year and around the country through trips that our faculty members undertake with our students. Thereby, they reach places where students perhaps cannot attend the main event during its celebration. As a successful program, it can be interesting to see if other countries can adopt this method to recruit or to trigger the interest of students to pursue their studies in the Sciences.
Planetario Habana: a cultural centre for science and technology in a developing nation
Authors: Álvarez Oscar
Published: August 2007

Astronomical education in Cuba is not widespread in the educational system; nevertheless the public interest in sciences in general but particularly in Astronomy issues is very high, as it has become reflected by the attention paid to educational and scientific program broadcasts in the national television channels. The “Planetario Habana” Cultural Centre for Science and Technology, which is under construction, is aimed at guiding the interest towards basic sciences and astronomical formation of the people, in the most populated and frequented area of the country. A key objective of this project shall be serving as an instructive motivation and entertainment for the casual or habitual visitors to these facilities, offering them the possibility to enjoy vivid representations, play with interactive amusement equipment and listen to instructive presentations on astronomy and related sciences, all guided by qualified specialists.

Another fundamental purpose shall be the establishment of a plan for complementary education in coordination with schools, in order to allow children and young people to participate in activities enabling them to get into the fascinating world of Astronomy, Exploration of Outer Space and Life as a Cosmic Phenomenon.

The setting up of the Planetario Habana Cultural Centre for Science and Technology is under the general administration of the Office of the Historian of the City of Havana, and methodologically is being led by the Ministry of Science, Technology and the Environment, and will show in operation the GOTO Planetarium G Cuba custom, obtained under a Japanese Cultural Grant Aid. It will develop into a an unparalleled centre in the national environment for scientific outreach and education of these sciences.

Surrounded by the attractiveness of the colonial “ambience’, it shall become a centre for dissemination of information about new discoveries and scientific programs developed at national and international level. Here we present a general view of the project, and its present and future development.
The first two years of the Latin-American Journal of Astronomy Education (RELEA)
Authors: Bretones Paulo Sérgio , Jafelice Luiz Carlos , Horvath J.E.
Published: August 2007

We present and discuss in this work the motivations, goals and strategies adopted for its creation and launch of the e-journal Latin-American Journal of Astronomy Education (RELEA). We identify and present the difficulties encountered for the achievement of the proposed objectives and operational issues in this period, together with the adopted solutions (refereeing procedure, periodicity, etc.).
A new astronomical facility for Peru: transforming a telecommunication's 32-metre antenna into a radio-telescope
Authors: Ishitsuka José , Ishitsuka M. , Kaifu N. , Inoue M. , Tsuboi M. , Ohishi M. , Kondo T. , Koyama Y. , Kasuga T. , Fujisawa K. , Miyazawa K. , Miyoshi M. , Umemoto T. , Bushimata T. , Horiuchi S. , Vidal E.
Published: August 2007

In 1984 an INTELSAT antenna of 32 m of diameter was constructed at 3 370 metres above the sea level on the Peruvian Andes. At the time Entel Perú the Peruvian tele-communications company managed the antenna station, of almost 12 hectares in extension. In 1993 the government transferred the station to the private telecommunications company Telefónica del Perú. Since transoceanic fiber optics replaced radically satellite communications in 2002, a beautiful 32- metre parabolic antenna was finished its tele-communications mission and become available for other use. So in cooperation with the National Astronomical Observatory of Japan we began coordination to transform the antenna into a radio-telescope.

Researches on interstellar medium around Young Stellar Objects (YSO) are possible using methanol maser that emits at 6.7 GHz, so initially we will monitor and survey maser sources at the southern sky. An ambient temperature receiver withTrx= 60 K was developed at Nobeyama Radio Observatory and is ready to be installed. The antenna will be controlled by the Field System FS9 software installed in a PC within a Linux environment. An interface between antenna and PC was developed at Kashima Space Research Center in Japan by Mr E. Vidal.

In the near future S-band (2 GHz), X-band (8GHz), 12 GHz and 22 GHz observations are planned.

The peculiar position and altitude of the Peruvian Radio Observatory will be useful for VLBI observations with the VLBA for astronomical observation and geodetic measurements. For Peru where few or almost non astronomical observational instruments are available for research, implementation of the first radio observatory is a big step to foster sciences at graduate and postgraduate levels of universities.

Worldwide tele-communications antennas recently tend to finish their role as tele-communications antennas. Several of them are transformed into useful observational instruments.
Astronomy education in Morocco–a new project for implementing astronomy in high schools
Authors: Darhmaoui Hassane , Loudiyi K.
Published: August 2007

Astronomy education in Morocco, as in many developing countries, is not well developed and lacks the very basics in terms of resources, facilities and research. In 2004, the International Astronomical Union (IAU) signed an agreement of collaboration with Al Akhawayn University in Ifrane (AUI) to support the continued, long-term development of astronomy and astrophysics in Morocco. This is within the IAU programme Teaching for Astronomy Development (TAD). The initial focus of the programme concentrated exclusively on the University's Bachelor of Science degree programme. Within this programme, and during two years, we were successful in providing adequate astronomy training to our physics faculty and few of our engineering students. We also offered our students and community general astronomy background through courses, invited talks and extra-curricular activities. The project is now evolving towards a wider scope and seeks to promote astronomy education at the high school level. It is based on modules from the Hands on Universe (HOU) interactive astronomy programme. Moroccan students will engage in doing observational astronomy using their personal computers. They will have access to a worldwide network of telescopes and will interact with their peers abroad. Through implementing astronomy education at this lower age, we foresee an increasing interest among our youth not only in astronomy but also in physics, mathematics, and technology. The limited astronomy resources, the lack of teacher experience in the field and the language barrier are amongst the difficulties that we will be facing in achieving the objectives of this new programme.
Effect of altitude on aerosol optical properties
Authors: Bounhir Aziza , Benkhaldoun Zouhair , Siher El Arbi , Masmoudi L.
Published: August 2007

The ELT project is currently under way in Europe and North America. Astronomical sites depend critically on sky transparency and on aerosol loadings. A quantitative survey of aerosol optical properties at candidate ELT sites is an essential part of the site selection process. There are basically two methods to characterize aerosol properties: ground based measurements and satellite measurements. In this paper we will establish a full climatology of two sites very close to each other, but at a difference of 2300m in altitude: Izaña and Santa Cruz located in the Canary Islands. Both have sun photometers from the AERONET network. We also use the aerosol index determined from TOMS satellite data to determine how aerosol optical properties vary with altitude. We establish a correlation between the TOMS index and the aerosol optical thickness in both sites. Aerosol optical properties show very good correlation between Izaña and Santa Cruz. As a result we establish a set of relationships helpful to characterize sites at elevated altitude from data of neighbouring sites at low altitude.
Astronomy in Vietnam
Authors: Lan Nguyen Quynh , Huan Nguyen Dinh
Published: August 2007

In this paper we summarize the history and current state of astronomy in Vietnam. Future plans for the development of astronomy education and research in Vietnam are summarized and some avenues suggested. These include the construction of a planetarium in Hanoi, and the development of a curriculum for an undergraduate major and a Master's degree in astrophysics at some Universities, as well as the development and operation of an observatory in Hanoi.
Astronomy in the former Soviet Union 15 years after the breakup of the USSR
Authors: Bochkarev Nikolai G.
Published: August 2007

During the immediate post-Soviet period, the main infrastructure of astronomy over the territory of the former Soviet Union (FSU) was saved, in spite of dramatic decreases in financial support. Overall the situation for FSU astronomy is now stable. In Latvia, the 32-m radio-dish is in working order. This allows it to participate in VLBI programmes. In Russia, all three 32-metre radio dishes of the QUASAR VLBI system are operational, as well as the 2-m telescope with a high-resolution spectrograph (up to resolution R≃ 500 000) and the horizontal solar telescope (R= 320 000) of the Russian-Ukrainian Observatory on Peak Terskol (Caucasus, altitude 3100 m). However the situation with the observatory itself is worrying, because of the regional authorities' attempt to privatize its infrastructure.

The process of equipping a number of Commonwealth of Independent States (CIS) (including Russian) observatories with CCD-cameras is in progress. To solve staff problems, Kazakhstan, Tajikistan and Uzbekistan have begun to prepare national specialists in astronomy, and the Baltic States, Armenia, Azerbaijan, Georgia, Russia, and Ukraine continue to prepare astronomers.

Teaching of astronomy at schools is obligatory only in the Ukraine and partially in the Baltic states. To maintain a “common astronomical area”, the Eurasian Astronomical Society (EAAS) continues its programme of reduced-price subscription to Russian-language astronomical journals and magazines in the territory of FSU, the organization of international conferences and Olympiads for school students, and lectures for school teachers and planetarium lecturers, etc.

Telescopes in Russia and other CIS territories permit to monitor an object more then 12 hours and can be used in global monitoring programmes. The Central Asian sites have some of the very best astro-climates in the world. They are similar to (or a little better than) the well known Chilean sites (median seeing 0.7′′, very high fraction of clear nights, no light pollution and no high wind). It is imperative that these sites be protected and intensively used by the international astronomical community.