Complete Embedded Self-Translating Surfaces under Mean Curvature Flow

We describe a construction of complete embedded self-translating surfaces under mean curvature flow by desingularizing the intersection of a finite family of grim reapers in general position.Comment: 42 pages, 8 figures. v2: typos correcte

Area minimizing discs in metric spaces

We solve the classical problem of Plateau in the setting of proper metric spaces. Precisely, we prove that among all disc-type surfaces with prescribed Jordan boundary in a proper metric space there exists an area minimizing disc which moreover has a quasi-conformal parametrization. If the space supports a local quadratic isoperimetric inequality for curves we prove that such a solution is locally Hölder continuous in the interior and continuous up to the boundary. Our results generalize corresponding results of Douglas Radò and Morrey from the setting of Euclidean space and Riemannian manifolds to that of proper metric spaces

Latency-Constrained Fading Mitigation for Coherent Optical Feeder Links based on Space-Time-Frequency Coding

Optical feeder links (OFLs) benefit from the vast amount of bandwidth available in the THz-regime of the electromagnetic spectrum, and can be considered as enablers for future terabit-per-second satellite systems. A particular challenge for OFLs is to mitigate the effects of fading, caused by a combination of turbulence-induced scintillation, beam wander and pointing errors. The conventional solution is to exploit temporal diversity by a combination of interleaving and forward error correction (FEC). In this study we present an overview of fading mitigation techniques for latency-constrained coherent ground-to-satellite OFL and contribute a generic model which combines various diversity schemes including temporal, spatial, frequency and site diversity. To unlock spatial diversity, multi-beam space-time block coding and multi-beam, multi-λ are proposed and simulated. Though space-time block coding (STBC) provides more diversity gain, it requires accurate timing synchronization at the transmitter and channel state information at the receiver. Temporal, frequency and site diversity all rely on some form of interleaving and the potential diversity, pros and cons of each of these diversity techniques are covered in the presented study. In general, with a strict latency constraint and a tight link budget, frequency diversity, spatial diversity - either by STBC or multi-beam multi-λ - and site diversity can be effective methods to mitigate the effects of fading and close the link budget.</p

Perspectives of couples with high risk of transmitting genetic disorders.

Objective: To investigate the preference for preimplantation genetic diagnosis (PGD) as an alternative to prenatal diagnosis (PND) in a large group of couples representing a wide array of genetic disorders. We also investigated the couple's familiarity with PGD and presented time trade-off scenarios for PGD versus PND, as PGD treatment is regularly accompanied by waiting lists. Design: Questionnaire study. Setting: Patient organizations representing genetic disorders. Patient(s): A total of 210 couples carrying genetic disorders. Main outcome measure(s): Preference for PGD or PND and familiarity with PGD in carrier couples. Result(s): Fifteen organizations representing 38 genetic disorders agreed to participate. Nine hundred eighty-three couples responded. In total 210 couples were in their reproductive years (women 18-40 years) and had a desire to conceive. Ninety couples (42%) had never heard of PGD. After they were informed, 127 couples (60%) wanted to have diagnostic testing (PND or PGD) performed. Ninety-four (74%) of these couples preferred testing with PGD. When no waiting list was used 102 couples (80%) preferred PGD. With a 2-year waiting list for PGD, 58 couples (46%) would opt for PGD. Conclusion(s): Many carrier couples are unaware of the existence of PGD. When informed, most couples prefer PGD more than PND. The preference for PGD decreases with longer waiting lists. (aut. ref.

Reproductive outcome after PGD in couples with recurrent miscarriage carrying a structural chromosome abnormality: a systematic review.

BACKGROUND: Preimplantation genetic diagnosis (PGD) has been stated to improve live birth rates compared with natural conception in couples with recurrent miscarriage (RM) carrying a structural chromosome abnormality. It is unclear to what extent this claim can be substantiated by evidence. A systematic review of the literature was performed on the reproductive outcome of these couples after natural conception or after PGD. METHODS: MEDLINE, EMBASE and the Cochrane database were searched until April 2009. Trials, patient series and case reports describing reproductive outcome in couples with RM carrying a structural chromosome abnormality after natural conception and/or after PGD were included. Since no randomized controlled trials or non-randomized comparative studies were found, separate searches for both groups were conducted. Primary outcome measure was live birth rate per couple. Secondary outcome measure was miscarriage rate per couple. RESULTS: Four observational studies reporting on the reproductive outcome of 469 couples after natural conception and 21 studies reporting on the reproductive outcome of 126 couples after PGD were found. After natural conception, live birth rate per couple varied between 33 and 60% (median 55.5%) after parental chromosome analysis; miscarriage rate ranged from 21 to 40% (median 34%). After PGD, live birth rate per couple varied between 0 and 100% (median 31%) after parental chromosome analysis; miscarriage rate ranged from 0 to 50% (median 0%). CONCLUSIONS: Currently, there are insufficient data indicating that PGD improves the live birth rate in couples with RM carrying a structural chromosome abnormality. (aut.ref.

Unwillingness to participate in health checks for cardiometabolic diseases: a survey among primary health care patients in five European countries.

Background and aims Since cardiometabolic diseases (CMD) are a frequent cause of death worldwide, preventive strategies are needed. Recruiting adults for a health check could facilitate the identification of individuals at risk for CMD. For successful results, participation is crucial. We aimed to identify factors related to unwillingness to participate in CMD health checks. Methods We performed a cross‐sectional study in the Czech Republic, Denmark, Greece, the Netherlands, and Sweden. A questionnaire was distributed among persons without known CMD consulting general practice between January and July 2017 within the framework of the SPIMEU study. Results In total, 1354 persons responded. Nine percent was unwilling to participate in a CMD health check. Male gender, smoking, higher self‐rated health, never been invited before, and not willing to pay were related to unwillingness to participate. The most mentioned reason for unwillingness to participate was “I think that I am healthy” (57%). Among the respondents who were willing to participate, 94% preferred an invitation by the general practitioner and 66% was willing to pay. Conclusion A minority of the respondents was unwilling to participate in a CMD health check with consistent results within the five countries. This provides a promising starting point to increase participation in CMD health checks in primary care