On Cr−C^r-closing for flows on 2-manifolds

For some full measure subset B of the set of iet's (i.e. interval exchange transformations) the following is satisfied: Let X be a $C^r$, $1\le r\le \infty$, vector field, with finitely many singularities, on a compact orientable surface M. Given a nontrivial recurrent point $p\in M$ of X, the holonomy map around p is semi-conjugate to an iet $E :[0,1) \to [0,1).$ If $E\in B$ then there exists a $C^r$ vector field Y, arbitrarily close to X, in the $C^r-$topology, such that Y has a closed trajectory passing through p.Comment: 7 pages, 1 figur

Testing for stock market integration in a developing economy: Colombia

This paper examines the linkage between two parallel stock exchanges trading the same shares in Colombia, namely the Bogotá Stock Exchange and the Medellín Stock Exchange. We provide empirical evidence to support the hypothesis that these two markets can be best described as fully integrated over a period of almost four decades, which is consistent with the view that arbitrage opportunities are only possible in the short but not in the long run. In addition, we find evidence that the location of a company´s headquarters appears to matter in stock price formation.Stock market, cointegration, arbitrage, Colombia

Modeling of the Terminal Velocities of the Dust Ejected Material by the Impact

We compute the distribution of velocities of the particles ejected by the impact of the projectile released from NASA Deep Impact spacecraft on the nucleus of comet 9P/Tempel 1 on the successive 20 hours following the collision. This is performed by the development and use of an ill-conditioned inverse problem approach, whose main ingredients are a set of observations taken by the Narrow Angle Camera (NAC) of OSIRIS onboard the Rosetta spacecraft, and a set of simple models of the expansion of the dust ejecta plume for different velocities. Terminal velocities are derived using a maximum likelihood estimator. We compare our results with published estimates of the expansion velocity of the dust cloud. Our approach and models reproduce well the velocity distribution of the ejected particles. We consider these successful comparisons of the velocities as an evidence for the appropriateness of the approach. This analysis provides a more thorough understanding of the properties of the Deep Impact dust cloud.Comment: Comments: 6 pages, 2 Postscript figures, To appear in the proceedings of "Deep Impact as a World Observatory Event - Synergies in Space, Time", ed. Hans Ulrich Kaeufl and Chris Sterken, Springer-Verla

Topological first-order solitons in a gauged CP(2)CP(2) model with the Maxwell-Chern-Simons action

We verify the existence of radially symmetric first-order solitons in a gauged $CP(2)$ scenario in which the dynamics of the Abelian gauge field is controlled by the Maxwell-Chern-Simons action. We implement the standard Bogomol'nyi-Prasad-Sommerfield (BPS) formalism, from which we obtain a well-defined lower bound for the corresponding energy (i.e. the Bogomol'nyi bound) and the first-order equations saturating it. We solve these first-order equations numerically by means of the finite-difference scheme, therefore obtaining regular solutions of the effective model, their energy being quantized according the winding number rotulating the final configurations, as expected. We depict the numerical solutions, whilst commenting on the main properties they engender.Comment: 8 pages, 9 figure

Telecommunications and economic growth: an empirical analysis of sub-saharan Africa

We examine the effect on economic growth of mobile cellular phones in sub-Saharan Africa where a marked asymmetry is present between land-line penetration and mobile telecommunications expansion. This study extends previous ones along two important dimensions. First, we allow for the potential endogeneity between economic growth and telecommunications expansion by employing a special linear generalized method of moments (GMM) estimator. Second, we explicitly model for varying degrees of substitutability between mobile cellular and land-line telephony, so that greater expansion of mobile telecommunications can have a different impact whenever the level of land-line penetration differs. We find that mobile cellular phone expansion is an important determinant of the rate of economic growth in Sub-Saharan Africa. Moreover, we find that the contribution of mobile cellular phones to economic growth has been growing in importance in the region, and that the marginal impact of mobile telecommunication services is even greater wherever land-line phones are rare. Given the low cost of mobile telecommunications technology relative to other broad infrastructure projects, especially land-line infrastructure, we advocate that mobile telecommunication services be encouraged in the area.

Comparing alignment factors in SMEs and large organizations: a planning integration perspective

Measurement of the alignment between business strategies and information systems (IS) has demonstrated positive impact for the organizational performance. The factors that have proved relevant when assessing the maturity level of alignment are: communication, competency/value measurement, governance, partnership, architecture & scope, and skills. Existing research, however, has focused on the assessment of these factors on large organizations and has barely explored their impact on Small and Medium Enterprises (SME). This paper uses the data provided by 127 participants from large and SMEs in order to identify whether the aforementioned factors are also relevant for assessing the level of alignment maturity in SMEs. The results from this research suggest that there are not significant differences between large organizations and SMEs when assessing those factors. In addition, this research also explored the relation between different planning integration of alignment (independent, sequential and simultaneous) in order to measure the perceived relevance of the factors. The results suggest that the planning integration identified on SMEs and large organizations has a positive correlation on how these factors are ranked. For both SMEs and large organizations where the formulation is simultaneous, the relevance of the factors is higher perceived than it is for those where the formulation is independent or sequential

Maternal haemodynamic function differs in pre‐eclampsia when it is associated with a small‐for‐gestational‐age newborn: a prospective cohort study

Objective To describe maternal haemodynamic differences in gestational hypertension with small‐for‐gestational‐age babies (HDP + SGA), gestational hypertension with appropriate‐for‐gestational‐age babies (HDP‐only) and control pregnancies. Design Prospective cohort study. Setting Tertiary Hospital, UK. Population Women with gestational hypertension and healthy pregnant women. Methods Maternal haemodynamic indices were measured using a non‐invasive Ultrasound Cardiac Output Monitor (USCOM‐1A®) and corrected for gestational age and maternal characteristics using device‐specific reference ranges. Main outcome measures Maternal cardiac output, stroke volume, systemic vascular resistance. Results We included 114 HDP + SGA, 202 HDP‐only and 401 control pregnancies at 26–41 weeks of gestation. There was no significant difference in the mean arterial blood pressure (110 versus 107 mmHg, P = 0.445) between the two HDP groups at presentation. Pregnancies complicated by HDP + SGA had significantly lower median heart rate (76 versus 85 bpm versus 83 bpm), lower cardiac output (0.85 versus 0.98 versus 0.97 MoM) and higher systemic vascular resistance (1.4 versus 1.0 versus 1.2 MoM) compared with control and HDP‐only pregnancies, respectively (all P < 0.05). Conclusion Women with HDP + SGA present with more severe haemodynamic dysfunction than HDP‐only. Even HDP‐only pregnancies exhibit impaired haemodynamic indices compared with normal pregnancies, supporting a role of the maternal cardiovascular system in gestational hypertension irrespective of fetal size. Central haemodynamic changes may play a role in the pathogenesis of pre‐eclampsia and should be considered alongside placental aetiology

Probabilistic Combination of Noisy Points and Planes for RGB-D Odometry

This work proposes a visual odometry method that combines points and plane primitives, extracted from a noisy depth camera. Depth measurement uncertainty is modelled and propagated through the extraction of geometric primitives to the frame-to-frame motion estimation, where pose is optimized by weighting the residuals of 3D point and planes matches, according to their uncertainties. Results on an RGB-D dataset show that the combination of points and planes, through the proposed method, is able to perform well in poorly textured environments, where point-based odometry is bound to fail.Comment: Accepted to TAROS 201

Clinical features of alcoholic hepatitis in latinos and caucasians: A single center experience.

AimTo study differences of presentation, management, and prognosis of alcoholic hepatitis in Latinos compared to Caucasians.MethodsWe retrospectively screened 876 charts of Caucasian and Latino patients who were evaluated at University of California Davis Medical Center between 1/1/2002-12/31/2014 with the diagnosis of alcoholic liver disease. We identified and collected data on 137 Caucasians and 64 Latinos who met criteria for alcoholic hepatitis, including chronic history of heavy alcohol use, at least one episode of jaundice with bilirubin ≥ 3.0 or coagulopathy, new onset of liver decompensation or acute liver decompensation in known cirrhosis within 12 wk of last drink.ResultsThe mean age at presentation of alcoholic hepatitis was not significantly different between Latinos and Caucasians. There was significant lower rate of overall substance abuse in Caucasians compared to Latinos and Latinos had a higher rate of methamphetamine abuse (12.5% vs 0.7%) compared to Caucasians. Latinos had a higher mean number of hospitalizations (5.3 ± 5.6 vs 2.7 ± 2.7, P = 0.001) and mean Emergency Department visits (9.5 ± 10.8 vs 4.5 ± 4.1, P = 0.017) for alcohol related issues and complications compared to Caucasians. There was significantly higher rate of complications of portal hypertension including gastrointestinal bleeding (79.7% vs 45.3%, P &lt; 0.001), spontaneous bacterial peritonitis (26.6% vs 9.5%, P = 0.003), and encephalopathy (81.2% vs 55.5%, P = 0.001) in Latinos compared to Caucasians.ConclusionLatinos have significant higher rates of utilization of acute care services for manifestations alcoholic hepatitis and complications suggesting poor access to outpatient care