Investigations of the Non-Linear LMC Cepheid Period-Luminosity Relation with Testimator and Schwarz Information Criterion Methods

In this paper, we investigate the linearity versus non-linearity of the Large Magellanic Cloud (LMC) Cepheid period-luminosity (P-L) relation using two statistical approaches not previously applied to this problem: the testimator method and the Schwarz Information Criterion (SIC). The testimator method is extended to multiple stages for the first time, shown to be unbiased and the variance of the estimated slope can be proved to be smaller than the standard slope estimated from linear regression theory. The Schwarz Information Criterion (also known as the Bayesian Information Criterion) is more conservative than the Akaike Information Criterion and tends to choose lower order models. By using simulated data sets, we verify that these statistical techniques can be used to detect intrinsically linear and/or non-linear P-L relations. These methods are then applied to independent LMC Cepheid data sets from the OGLE project and the MACHO project, respectively. Our results imply that there is a change of slope in longer period ranges for all of the data sets. This strongly supports previous results, obtained from independent statistical tests, that the observed LMC P-L relation is non-linear with a break period at/around 10 days.Comment: 9 pages, 5 figures and 3 tables, PASP accepte

Adaptive end-to-end optimization of mobile video streaming using QoS negotiation

Video streaming over wireless links is a non-trivial problem due to the large and frequent changes in the quality of the underlying radio channel combined with latency constraints. We believe that every layer in a mobile system must be prepared to adapt its behavior to its environment. Thus layers must be capable of operating in multiple modes; each mode will show a different quality and resource usage. Selecting the right mode of operation requires exchange of information between interacting layers. For example, selecting the best channel coding requires information about the quality of the channel (capacity, bit-error-rate) as well as the requirements (latency, reliability) of the compressed video stream generated by the source encoder. In this paper we study the application of our generic QoS negotiation scheme to a specific configuration for mobile video transmission. We describe the results of experiments studying the overall effectiveness, stability, and dynamics of adaptation of our distributed optimization approach

The Ethiopian Federal Ethics and Anti-Corruption Commission: A Critical Assessment

The Ethiopian FEACC is a dedicated anti-corruption agency, invested with expansive powers to combat corruption in the country.  It was established in 2001 in the context of the accelerated internationalisation of anti-corruption law. The mandate of the FEACC is wide, spanning the prevention, investigation and prosecution of all forms of corruption in Ethiopia. This article seeks to evaluate critically the performance of the FEACC in the execution of its mandate during the first decade of its existence.  To this end it situates the creation and design of the FEACC within the global context of anti-corruption agencies, and seeks to assess its performance against generally accepted criteria, such as independence and accountability. The article seeks also to identify legal, political and institutional impediments to the success of the FEACC and proposes possible routes to overcoming such impediments.  The FEACC’s first decade has been a mixed one, with some notable successes offset against a number of inadequacies in need of significant and urgent attention

CROSS COMPLIANCE AND COMPETITIVENESS OF THE EUROPEAN BEEF AND PIG SECTOR

Beef and pig production are important sectors affected by the cross-compliance policy. Full compliance with SMRs and GAECs generates costs and benefits which may have an impact on the competitiveness of these sectors on the world market. Compliance with the Nitrate Directive, animal identification and registration requirements and animal welfare standards can give rise to non-negligible cost of production increases at individual farm level and at sector level. Additional costs can be relevant either due to a low degree of compliance or by significant adjustments costs at farm level. Full compliance generates a level playing field between Member States of the EU, as some countries have to face higher additional costs than others, which are be attributed to differences in degree of compliance. This paper first presents evidence of additional costs at individual farm level due to full compliance. Then for beef and pork a methodology has been developed in order to calculate sector cost impacts following an upcsaling procedure for each of the analysed directives. Simulations with the GTAP model have enabled an assessment of the trade effect of compliance with standards and the impact on the external competitiveness of the EU beef and pork production. In some policy fields covered by cross-compliance important trade partners such as Canada, USA and New Zealand have implemented policies similar to the EU. In these three countries comparable standards to those in the EU were identified and the level and cost of compliance have been assessed. The pig sector will be affected most by a unilateral compliance with standards in the EU, in particular as the Nitrate Directive is concerned. Within the EU pig production costs will rise by 0.545 %. Imports may increase by 4% and exports may fall by 3%. However full application of the Clean Water Act in the US, which contains similar obligations to the Nitrate Directive, generates a significant sector cost increase (1,08%) which may counterbalance the loss of competitiveness of EU pork production towards the US. Compliance with the mandatory animal welfare standards has only minor cost implications and has negligible effects on external competitiveness of the EU both because of a high degree of compliance and relatively low adjustment costs at farm level. Finally, in many EU member states the degree of compliance of beef farms with the animal registration and identification directives is below 100%. Additional costs for full compliance within the EU have been estimated at 0.455%, which may cause an increase of beef imports of 2.21% and a decline of exports of –2.12%. This loss in competitiveness of the EU will further favour the position of Brazil on the world beef market. At the other hand significant benefits are obtained in food security of EU beef.Cross compliance, beef sector, pork sector, Agricultural and Food Policy, Q10, Q18,

Neural differentiation is moderated by age in scene- but not face-selective cortical regions

The aging brain is characterized by neural dedifferentiation, an apparent decrease in the functional selectivity of category-selective cortical regions. Age-related reductions in neural differentiation have been proposed to play a causal role in cognitive aging. Recent findings suggest, however, that age-related dedifferentiation is not equally evident for all stimulus categories and, additionally, that the relationship between neural differentiation and cognitive performance is not moderated by age. In light of these findings, in the present experiment, younger and older human adults (males and females) underwent fMRI as they studied words paired with images of scenes or faces before a subsequent memory task. Neural selectivity was measured in two scene-selective (parahippocampal place area (PPA) and retrosplenial cortex (RSC)] and two face-selective [fusiform face area (FFA) and occipital face area (OFA)] regions using both a univariate differentiation index and multivoxel pattern similarity analysis. Both methods provided highly convergent results, which revealed evidence of age-related reductions in neural dedifferentiation in scene-selective but not face-selective cortical regions. Additionally, neural differentiation in the PPA demonstrated a positive, age-invariant relationship with subsequent source memory performance (recall of the image category paired with each recognized test word). These findings extend prior findings suggesting that age-related neural dedifferentiation is not a ubiquitous phenomenon, and that the specificity of neural responses to scenes is predictive of subsequent memory performance independently of age

Influence of notch orientation on ductile tearing in SENT specimens

There is a growing interest for the use of spiral welded pipes in strain based design related applications. Since the influence of the spiral weld on the plastic behaviour of the pipe is not yet fully understood, further research on this topic is required. An important aspect of this plastic behaviour is the effect of mixed mode loading on weld defects located in the helical weld. This paper elaborates on the first experimental trials to evaluate ductile tearing by means of single edge notched tensile specimen (SENT) testing with slanted notches. Tests were performed on two SENT specimens, one with a slanted notch and another with a straight notch in order to investigate the influence of mixed mode loading. The crack mouth opening displacement and crack extension were determined experimentally by means of digital image correlation and potential drop measurements respectively. The crack extension and the potential drop measurements were related by means of finite element simulations

Orbital Characteristics of the Subdwarf-B and F V Star Binary EC~20117-4014(=V4640 Sgr)

Among the competing evolution theories for subdwarf-B (sdB) stars is the binary evolution scenario. EC~20117-4014 (=V4640~Sgr) is a spectroscopic binary system consisting of a pulsating sdB star and a late F main-sequence companion (O'Donoghue et al. 1997), however the period and the orbit semi-major axes have not been precisely determined. This paper presents orbital characteristics of the EC 20117-4014 binary system using 20 years of photometric data. Periodic Observed minus Calculated (O-C) variations were detected in the two highest amplitude pulsations identified in the EC 20117-4014 power spectrum, indicating the binary system's precise orbital period (P = 792.3 days) and the light-travel time amplitude (A = 468.9 s). This binary shows no significant orbital eccentricity and the upper limit of the eccentricity is 0.025 (using 3 $\sigma$ as an upper limit). This upper limit of the eccentricity is the lowest among all wide sdB binaries with known orbital parameters. This analysis indicated that the sdB is likely to have lost its hydrogen envelope through stable Roche lobe overflow, thus supporting hypotheses for the origin of sdB stars. In addition to those results, the underlying pulsation period change obtained from the photometric data was $\dot{P}$ = 5.4 ($\pm$0.7) $\times$ $10^{-14}$ d d$^{-1}$, which shows that the sdB is just before the end of the core helium-burning phase