Rationally cubic connected manifolds I: manifolds covered by lines

In this paper we study smooth complex projective polarized varieties (X,H) of dimension n \ge 2 which admit a dominating family V of rational curves of H-degree 3, such that two general points of X may be joined by a curve parametrized by V, and such that there is a covering family of rational curves of H-degree one. Our main result is that the Picard number of these manifolds is at most three, and that, if equality holds, (X,H) has an adjuction theoretic scroll structure over a smooth variety

Feasibility of Sleep Self-Management Intervention in Pregnancy Using a Personalized Health Monitoring Device: Protocol for a Pilot Randomized Controlled Trial

Background: Sleep disruptions are common during pregnancy and associated with increased risk of adverse maternal outcomes such as preeclampsia, gestational diabetes, prolonged labor, and cesarean birth. Given the morbidity associated with poor sleep, cost-effective approaches to improving sleep that can be disseminated in community or clinical settings are needed. Personal health monitor (PHM) devices offer an opportunity to promote behavior change, but their acceptability and efficacy at improving sleep in pregnant women are unknown. Objective: The goal of the paper is to describe the protocol for an ongoing pilot randomized controlled trial that aims to establish the feasibility, acceptability, and preliminary efficacy of using a PHM device (Shine 2, Misfit) to promote sleep during pregnancy. Methods: The proposed pilot study is a 12-week, parallel arm, randomized controlled trial. Pregnant women, at 24 weeks gestation, will be randomized at a 1:1 ratio to a 12-week sleep education plus PHM device group or a sleep education alone comparison group. The primary outcomes will be measures of feasibility (ie, recruitment, enrollment, adherence) and acceptability (ie, participant satisfaction). The secondary outcomes will be self-reported sleep quality and duration, excessive daytime sleepiness, fatigue, and depressive symptoms. Results: Recruitment for this study began in September 2017 and ended in March 2018. Data collection for the primary and secondary aims was completed in August 2018. We anticipate that the data analysis for primary and secondary aims will be completed by December 2019. The results from this trial will inform the development of a larger National Institutes of Health grant application to test the efficacy of an enhanced version of the sleep intervention that we plan to submit in the year 2020. Conclusions: This study will be the first to apply a PHM device as a tool for promoting self-management of sleep among pregnant women. PHM devices have the potential to facilitate behavioral interventions because they include theory-driven, self-regulatory techniques such as behavioral self-monitoring. The results of the study will inform the development of a sleep health intervention for pregnant women. Trial Registration: ClinicalTrials.gov NCT03783663; https://clinicaltrials.gov/ct2/show/NCT03783663 (Archived by WebCite at http://www.webcitation.org/779Ou8hon) International Registered Report Identifier (IRRID): DERR1-10.2196/1245

Do workers'remittances reduce the probability of current account reversals ?

The authors combine the literature on financial crises in emerging markets and developing economies with that on international migrations by investigating whether the increasingly large flows of workers'remittances can help reduce the probability of current account reversals. The rationale for this stands in the great stability and low cyclicality of remittances as compared with other private capital flows: these properties, combined with the fact that remittances are cheap inflows of foreign currencies, might reduce the probability that foreign investors suddenly flee out of emerging markets and developing economies and trigger a dramatic current account adjustment. The authors find that remittances can have such a beneficial effect. In particular, they show that a high level of remittances, as a ratio of GDP, makes the relationship between a decreasing stock of international reserves (over GDP) and a higher probability of current account crises less stringent. The same occurs, though less neatly, for the positive relationship between an increasing stock of external debt (over GDP) and the probability of current account reversals. The results point also to a threshold effect of remittances: the mechanisms just described are, in fact, much stronger when remittances are above 3 percent of GDP.Macroeconomic Management,External Debt,Financial Economics,Economic Theory&Research,Free Trade

Relativistic effects in the solar EOS

We study the sensitivity of the sound speed to relativistic corrections of the equation of state (EOS) in the standard solar model by means of a helioseismic forward analysis. We use the latest GOLF/SOHO data for $\ell = 0,1,2,3$ modes to confirm that the inclusion of the relativistic corrections to the adiabatic exponent $\Gamma_1$ computed from both OPAL and MHD EOS leads to a more reliable theoretical modelling of the innermost layers of the Sun.Comment: 3 pages, 3 figures, aa.cls, to appear on Astronomy and Astrophysic

The impact of origin region and internal migration on Italian fertility

We examine the impact of population distribution on fertility in a nationally representative sample. We exploit detailed life-history data to conduct an event-history analysis of transition to first birth, examining mechanisms that might link migration and fertility: socialization, adaptation, selection, and disruption. Our multivariate analysis examines various socio-demographic traits, the place of birth, and interregional migration. Differences by region and migration stream are partly explained by compositional factors, such as female employment, union type, and education. The analysis presents much evidence for demographic selection and socialization and less for adaptation or disruption. The persistence of the region of origin differentials points to the continuing importance of the context