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Objectives: To examine the implications of third-trimester small-for-gestational-age (SGA) screening accuracy on severe adverse perinatal outcome (SAPO) and obstetric intervention in a low-risk population. Furthermore, we aimed to explore the additive value of third-trimester sonographic growth-trajectory measurements in predicting SAPO and obstetric intervention. Methods: This was a secondary analysis of a Dutch national multicenter stepped-wedge-cluster randomized trial among 11 820 low-risk pregnant women. Using multilevel multivariable logistic regression analysis, we compared SAPO and obstetric interventions in SGA neonates with and without SGA suspected prenatally (true positives and false negatives) and non-SGA neonates with and without SGA suspected prenatally (false positives and true negatives). In a subsample (n = 7989), we analyzed the associations of abdominal circumference (AC) and estimated fetal weight (EFW) < 10 th centile (p10) and third-trimester growth-trajectory indicators AC and EFW crossing > 20 and AC crossing > 50 centiles and the lowest decile of AC growth-velocity Z-scores (ACGV < 10%) with SAPO and obstetric interventions. Results: SGA infants, i.e. the true-positive and false-negative cases, had an increased risk of SAPO (adjusted odds ratio (aOR), 4.46 (95% CI, 2.28–8.75) and aOR 2.61 (95% CI, 1.74–3.89), respectively), and obstetric intervention (aOR for: induction of labor, 2.99 (95% CI, 2.15–4.17) and 1.38 (95% CI, 1.14–1.66); Cesarean section, 1.82 (95% CI, 1.25–2.66) and 1.27 (95% CI, 1.05–1.54); medically indicated preterm delivery, 2.67 (95% CI, 1.97–3.62) and 1.20 (95% CI, 1.03–1.40)). The false-positive cases did not differ from the true negatives for all outcomes, including obstetric intervention. Of the third-trimester growth-trajectory indicators, only ACGV < 10% was associated moderately with SAPO (aOR, 2.15 (95% CI, 1.17–3.97)), while AC and EFW crossing > 20 and AC crossing > 50 centiles were not. Both EFW < p10 alone (aOR, 1.95 (95% CI, 1.13–3.38)) and EFW < p10 combined with ACGV < 10% (aOR, 4.69 (95% CI, 1.99–11.07)) were associated with SAPO, and they performed equally well in predicting SAPO (area under the receiver-operating-characteristics curve, 0.71 (95% CI, 0.65–0.76) vs 0.72 (95% CI, 0.67–0.77), P = 0.51). Conclusion: Neonates who had been suspected falsely of being SGA during pregnancy had no higher rates of obstetric intervention than did those without suspicion of SGA prenatally. Our results do not support that third-trimester low fetal growth velocity (ACGV < 10%) may be of additive value for the identification of fetuses at risk of SAPO in populations remaining at low risk throughout pregnancy. AC and EFW crossing > 20 and AC crossing > 50 centiles performed poorly in identifying abnormal fetal growth.

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Item does not contain fulltext OBJECTIVE: To determine if the verification of short cervical length with a repeated measurement improved the identification of patients with short cervical length at increased risk of preterm delivery. METHODS: The present secondary analysis analyzed prospective cohort study data from patients with singleton pregnancies without a history of preterm delivery who presented for obstetric care in the Netherlands and delivered between November 18, 2009, and January 1, 2013. Cervical length was measured during standard anomaly scan and a second measurement was performed if the cervical length was 30 mm of shorter. Logistic regression and Cox proportional hazards modeling were used to evaluate associations between cervical length measurements and spontaneous preterm delivery before 37 weeks of pregnancy. RESULTS: Cervical length measurements from 12 358 patients were included; 221 (1.8%) had an initial cervical length measurement of 30 mm or shorter. A second cervical length measurement was performed for 167 (75.6%) patients; no differences were identified in the odds of spontaneous preterm delivery when evaluated using the first, second, or a mean of both measurements, regardless of whether cervical length was analyzed as a continuous or dichotomous variable. CONCLUSION: Among patients with singleton pregnancies, verification of short cervical length did not improve the identification of short cervical length.

Neither breast cancer prevention and early-detection programs, nor their outcomes, are uniform across Europe. This article describes the rationale, methods, and process for development of the European Commission ( EC) Initiative on Breast Cancer Screening and Diagnosis Guidelines. To be consistent with standards set by the Institute of Medicine and others, the EC followed 6 general principles. First, the EC selected, via an open call, a panel with broad representation of areas of expertise. Second, it ensured that all recommendations were supported by systematic reviews. Third, the EC separately considered important subgroups of women, included patient advocates in the guidelines development group, and focused on good communication to inform women's decisions. Fourth, EC rules on conflicts of interest were followed and the GRADE ( Grading of Recommendations Assessment, Development and Evaluation) Evidence to Decision frameworks were used to structure the process and minimize the influence of competing interests. Fifth, it focused its recommendations on outcomes that matter to women, and certainty of the evidence is rated for each. Sixth, the EC elicited stakeholder feedback to ensure that the recommendations remain up to date and relevant to practice. This article describes the approach and highlights ways of disseminating and adapting the recommendations both within and outside Europe, using innovative information technology tools.

Objective: Inhibition of GH signaling has been associated with increased longevity and cancer resistance. As the fetal estrogen estetrol was also linked to longevity and cancer resistance, we hypothesized that these effects of estetrol are mediated by inhibition of GH activity. Design: The CNMm-6TR mammary cell line, stably transfected with doxycycline (DOX)-inducible GHR (CNMm-cGHR cells), HEK293 cell line transfected with rGHR and the human T47D cell line were used to assess effects of estetrol on GH signal transduction. Proliferation was measured using the colorimetric 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay (MTT). Spi-luciferase reporter activity, responsive to phosphorylated Stat5, was used to assess GH signaling. GHR mRNA expression was normalized to a reference gene. Results: Treatment of CNMm-cGHR cells with GH resulted in decreased proliferation rates. No effect was seen by the co-inhibition with estetrol. Using the spi-luc reporter activity, it was shown that GH activates the GHR/Jak2/ Stat5 pathway. Estetrol partially inhibited this activation. In the HEK-rGHR cells, estetrol was able to inhibit the GH induced activation of the spi-luc reporter, but only in the presence of an ERα expression plasmid. Effects of estetrol on the expression of GHR mRNA was assessed in T47D cells, a cell-line expressing ER, PR and GHR under natural promoters. After incubation with estetrol, a mean 4-fold inhibition of GHR mRNA expression was observed. Conclusion: Using different cell systems, it was shown that estetrol is able to inhibit GH signaling, a process dependent on the presence of the Estrogen Receptor (ER). Estetrol may therefore be used to inhibit GH-induced effects on breast cancer proliferation.

Objective: Inhibition of GH signaling has been associated with increased longevity and cancer resistance. As the fetal estrogen estetrol was also linked to longevity and cancer resistance, we hypothesized that these effects of estetrol are mediated by inhibition of GH activity. Design: The CNMm-6TR mammary cell line, stably transfected with doxycycline (DOX)-inducible GHR (CNMm-cGHR cells), HEK293 cell line transfected with rGHR and the human T47D cell line were used to assess effects of estetrol on GH signal transduction. Proliferation was measured using the colorimetric 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay (MTT). Spi-luciferase reporter activity, responsive to phosphorylated Stat5, was used to assess GH signaling. GHR mRNA expression was normalized to a reference gene. Results: Treatment of CNMm-cGHR cells with GH resulted in decreased proliferation rates. No effect was seen by the co-inhibition with estetrol. Using the spi-luc reporter activity, it was shown that GH activates the GHR/Jak2/ Stat5 pathway. Estetrol partially inhibited this activation. In the HEK-rGHR cells, estetrol was able to inhibit the GH induced activation of the spi-luc reporter, but only in the presence of an ERα expression plasmid. Effects of estetrol on the expression of GHR mRNA was assessed in T47D cells, a cell-line expressing ER, PR and GHR under natural promoters. After incubation with estetrol, a mean 4-fold inhibition of GHR mRNA expression was observed. Conclusion: Using different cell systems, it was shown that estetrol is able to inhibit GH signaling, a process dependent on the presence of the Estrogen Receptor (ER). Estetrol may therefore be used to inhibit GH-induced effects on breast cancer proliferation.

OBJECTIVE: To perform a systematic review and meta-analysis to assess the predictive capacity of transvaginal sonographic assessment of the cervix for the outcome of induction of labor.METHODS: We searched MEDLINE, EMBASE and the Cochrane Library, and manually searched reference lists of review articles and eligible primary articles. Studies in all languages were eligible if published in full. Two reviewers independently selected studies and extracted data on study characteristics, quality and test accuracy. We then calculated pooled sensitivities and specificities (with 95% CIs) and summary receiver-operating characteristics (sROC) curves. Outcome measures were test accuracy of sonographically measured cervical length and cervical wedging for Cesarean section, not achieving vaginal delivery within 24 h and not achieving active labor.RESULTS: We included 31 studies reporting on both cervical length and outcome of delivery. The quality of the included studies was mediocre. Sensitivity of cervical length in the prediction of Cesarean delivery ranged from 0.14 to 0.92 and specificity ranged from 0.35 to 1.00. The estimated sROC curve for cervical length indicated a limited predictive capacity in the prediction of Cesarean delivery. Summary estimates of sensitivity/specificity combinations of cervical length at different cut-offs for Cesarean delivery were 0.82/0.34, 0.64/0.74 and 0.13/0.95 for 20, 30 and 40 mm, respectively. For cervical wedging in the prediction of failed induction of labor summary point estimates of sensitivity/specificity were 0.37/0.80.CONCLUSIONS: Cervical length and cervical wedging as measured sonographically at or near term have moderate capacity to predict the outcome of delivery after induction of labor.

Pulsars with their periodic pulses and known positions are ideal beacons for navigation. The challenge, however, is the detection of the very weak pulsar signals that are submerged in noise. Radio based approaches allow the use of advanced techniques and methods for the detection and acquisition of such weak signals. In this paper, an effective signal acquisition method based on epoch folding and matched filtering is proposed that can enable pulsar navigation on spacecraft. Traditionally astronomers use an epoch folding algorithm to search for new pulsars which is a very time and processing power-consuming approach. Since a pulsar navigation system uses signals from known pulsars, advanced algorithms can reduce the time and processing power required for pulsar detection. Applying optimization methods on folding algorithms could lead to an increase in detection speed, however, it is not practical when taking all known signal parameters into account. In this paper a new approach is proposed to reduce the time and processing power further, considering a-priori knowledge such as pulse shape. This approach is based on the concept of matched filtering. Matched filtering is the basic tool for extracting known wavelets from a signal that has been contaminated by noise. A matched filter is obtained by correlating the observation with a template of a known signal, to detect its presence. Such a matched filter is the optimal linear filter for maximizing the signal-to-noise-ratio (SNR) in the presence of additive stochastic noise. After a description of the underlying theory, simulations shows that by using this method, significant increases in detection speeds are possible.

OBJECTIVE: We performed a systematic review to determine whether sonographic assessment of occipital position of the fetal head can contribute to the prediction of the mode of delivery.METHODS: We performed a systematic literature search of electronic databases from inception to May 2011. Two reviewers independently extracted data from the included studies. We used a bivariate model to estimate point estimates for sensitivity and specificity curves for the outcome Cesarean delivery. Eligible studies were cohort studies or cross-sectional studies that reported on both the position of the fetal head, as assessed by ultrasound, before or at the beginning of active labor as well as the outcome of labor in women at term.RESULTS: We included 11 primary articles reporting on 5053 women, of whom 898 had a Cesarean section. All studies indicated disappointing values for sensitivity and specificity in the prediction of Cesarean section. Summary point estimates of sensitivity and specificity were 0.39 (95% CI, 0.32-0.48) and 0.71 (95% CI, 0.67-0.74), respectively.CONCLUSION: Sonographic assessment of occipital position of the fetal head before delivery should not be used in the prediction of mode of delivery.

Nano-satellites have a cost advantage due to their low mass and usage of commercial-off-the-shelf technologies. However, the low mass also restricts the functionality of a nano-satellite's payload. Typically, this would imply instruments with very low to low resolution and accuracy, essentially ruling out applications such as remote sensing. However, multiple nano-satellites can cooperate to improve the overall system performance, for example by increasing the frequency of the observations. The objective of this study is to design a radar system that can be accommodated in a nano-satellite, and investigate the feasibility of using multiples of these nano-satellites to perform high temporal resolution remote sensing. In this paper therefore, the concept of a nano-satellite sized Synthetic Aperture Radar (Nano-SAR) is investigated. Nano-satellites have very constrained power and volume budgets, and there are limits to how much surface area they can unfold for use in radar. Given these constraints, a SAR system for use in a nano-satellite in a 350 km orbit was sized, and approaches to tackle the deficits in the radar link budget are proposed. When applying state-of-the-art technologies, both on the component level, as well as on an architectural level, one arrives at a closed link budget. The proposed radar system consists of a patch antenna array with a span of 1.14 m by 0.18 m, operating at a frequency of 5.8 GHz. Power amplification and phase shifting is performed on the panel, using digital radio frequency (RF) integrated Complementary Metal Oxide Semiconductor (CMOS) circuits. This results in a swath width of 60 km, with pixel sizes of 10 m in elevation direction. Given these performance values, coupled with the increased revisit times, it was obvious this radar, when flown in a larger swarm of nano-satellites, would allow faster now-casting for weather prediction. With significant investment in technology development, it could be possible to use this system for SAR interferometry, for near-real-time monitoring of fast ground deformation phenomena such as earthquakes and volcanoes. Other applications could lie in the field of near-real-time ship motion detection and oil spill spread detection. Many technical challenges need to be solved still and platforms need to be designed, capable of supporting this system, before this payload would be ready for deployment. Preliminary design suggests the cost of such an instrument is substantially higher than what is common for nano-satellite components. However, the potential of such a system is extremely promising, and merits further investigation.©2012 by the International Astronautical Federation.

Interstellar navigation poses significant challenges in all aspects of a spacecraft. One of them is reliable, low-cost, real-time navigation, especially when there is a considerable distance between Earth and the spacecraft in question. In this paper, a complete system for navigation using pulsar radio emissions is described and analysed. The system uses a pulsar?s emissions in the radio spectrum to create a novel system capable of fully autonomous navigation. The system is roughly divided into two parts, the front - end and the back - end, as well as their subdivisions. The front - end performs initial signal reception and pre-processing. It applies time-based coherent de-dispersion to allow for low-power on-board processing, and uses a very wide bandwidth to limit the required antenna size. As a result, the electronics required performing the processing is complex, but the system is well limited in both size and power consumption. The back-end, in turn, performs advanced nonlinear Kalman filtering and supplies the final navigational product - the systems complete (position and velocity) state vector, as well as the involved uncertainties. Rather uniquely, it uses two inherent signal properties, the Doppler shift and the inherent pulse period slowdown, simultaneously, to obtain both a relative and an absolute estimate of the spacecraft's position. Combined, in the nonlinear Kalman filter, they result in the complete state vector of the system. Performance of the system was analysed and validated using actual telescope data from the LOFAR array. The results show that the front-end can indeed receive and process even a very weak signal from an actual pulsar, while the back-end can output a navigational product despite significant random noise in the signal data received from the front-end.

Operations of satellites in Low-Earth Orbit (LEO) have been based on exploiting the maximum time of visibility of satellites over their ground stations. In this paper, it is shown that a key parameter for communication between a satellite and a ground station is not the time of visibility but the amount of telemetry data which can be transmitted from the satellite to the ground station in the downlink. Given the fact that advanced satellites may allow a variety of data rates for downlink, switching on and off the transponder at higher elevations (i.e. at lower slant ranges) than the minimum possible elevation allows for a higher data rate, and thus, despite of less contact time, for a higher total data volume to be transmitted during a given pass. The paper motivates this new approach for space-ground communication of satellites in LEO on the background of recent technology advances and develops the theoretical framework for enhanced communication. To this extent, an analytical relation is established of the total data volume which can be downlinked for a single pass as a function of the elevation at which the transponder shall be switched on and off. The analysis is limited to a circular LEO and zenith passes. Numerical simulations of the total data volume as a function of this minimum elevation angle are presented as well. Finally, associated opportunities and challenges for enhanced communications are identified and discussed. Conclusions are drawn for future optimized operations of LEO satellites based on given ground segments.

The CanSat competition is intended to give pupils the chance to get practical experience in building complex systems in a multidisciplinary environment. Aerospace is the place where this specific combination of science and engineering emerges. It is not only interesting for scientists and engineering students but also for parents and tutors. This interest and enthusiasm can contribute to change the general attitude of "engineering is difficult" to "engineering is fun". Pupils with a dormant interest in science and engineering can be stimulated by this project to choose a career in engineering.

Student satellites are the latest hype in education. By allowing students to build their own satellites, they learn to solve problems faster and build more innovatively. In Delft, students are now putting the final touches on the Delft-C3, a nanosatellite the size of a milk carton. For every student, and for the instructors as well, this a boys dream.

MISAT is a research and development cluster which will create a small satellite platform based on Micro Systems Technology (MST) aiming at innovative space as well as terrestrial applications. MISAT is part of the Dutch MicroNed program which has established a microsystems infrastructure to fully exploit the MST knowledge chain involving public and industrial partners alike. The cluster covers MST-related developments for the spacecraft bus and payload, as well as the satellite architecture. Particular emphasis is given to distributed systems in space to fully exploit the potential of miniaturization for future mission concepts. Examples of current developments are wireless sensor and actuator networks with plug and play characteristics, autonomous digital Sun sensors, re-configurable radio front ends with minimum power consumption, or micro-machined electrostatic accelerometer and gradiometer system for scientific research in fundamental physics as well as geophysics. As a result of MISAT, a first nano-satellite will be launched in 2007 to demonstrate the next generation of Sun sensors, power subsystems and satellite architecture technology. Rapid access to in-orbit technology demonstration and verification will be provided by a series of small satellites. This will include a formation flying mission, which will increasingly rely on MISAT technology to improve functionality and reduce size, mass and power for advanced technology demonstration and novel scientific applications.

Bacteria, polyps, ants, and bees are the living proof that, given inhospitable conditions, colonies stand a better chance of survival than individuals.At TU Delft, this biological principle is now being used on spacecraft. A colony of micro satellites will be less vulnerable than a normal satellite, not only to gamma radiation and solar storms, but also to cutbacks. After all, micro satellites are small and light, and will someday be mass-produced.

We integrate with hyperelliptic functions a two-particle Hamiltonian with quartic potential and additionnal linear and nonpolynomial terms in the Liouville integrable cases 1:6:1 and 1:6:8., Comment: LaTex 2e. To appear, Theoretical and Mathematical Physics 2003

The generalized H��non-Heiles Hamiltonian $H=1/2(P_X^2+P_Y^2+c_1X^2+c_2Y^2)+aXY^2-bX^3/3$ with an additional nonpolynomial term $��Y^{-2}$ is known to be Liouville integrable for three sets of values of $(b/a,c_1,c_2)$. It has been previously integrated by genus two theta functions only in one of these cases. Defining the separating variables of the Hamilton-Jacobi equations, we succeed here, in the two other cases, to integrate the equations of motion with hyperelliptic functions., LaTex 2e. To appear, Journal of Mathematical Physics

Nano-satellite IoT/M2M missions are gaining popularity in recent time. Various companies have launched their pilot missions last year in 2018 and all these companies intend to place a constellation in (V)LEO that can communicate with low power sensors on the ground (sometimes remote locations) and relay it back to the end-user who is monitoring these sensors. This paper discusses two possible architectures of using nano-satellites for low latency IoT/M2M, by presenting information such as, number of satellites needed, number of orbital planes needed and communication strategy. The first proposed architecture will comprise of a self-sustaining network of nano-satellites that communicate with low power, low data-rate sensors on the ground and relay the data to rest of the nano-satellites in the network using inter-satellite links, which is downlinked by a nano-satellite that is in the view of a ground station that is connected to IMT. The second proposed architecture will use nano-satellites to communicate with low power, low data-rate sensors on the ground and relay it to satellites that intend to provide internet from space (Mega-constellation). The internet constellations considered in this study for the second architecture are: Telesat’s constellation, SpaceX’s Starlink, OneWeb’s constellation, Astrome’s SpaceNet constellation and Audacy’s constellation. Using both these architectures, it can be seen that the latency can be reduced considerably.

Onderzoek naar transculturele verbindingen binnen de hogeschool en de mate waarin we binnen de hogeschool meervoudige identiteiten kunnen herkennen en erkennen en op basis daarvan duurzame samenwerkingsverbanden voor de toekomst kunnen ontwikkelen.

OLFAR, Orbiting Low Frequency Antennas for Radio Astronomy, will be a space mission to observe the universe frequencies below 30 MHz, as it was never done before with an orbiting telescope. Because of the ionospheric scintillations below 30 MHz and the opaqueness of the ionosphere below 15 MHz, a space mission is the only opportunity for this as yet unexplored frequency range in radio astronomy. The frequency band is scientifically very interesting for exploring the early cosmos at high hydrogen redshifts, the so-called dark-ages and the epoch of reionization, the discovery of planetary and solar bursts in other solar systems, for obtaining a tomographic view of space weather, ultra-high energy cosmic rays and for many other astronomical areas of interest. Because of the low observing frequency the aperture size of the instrument must be in the order of 100 km. This requires a distributed space mission which is proposed to be implemented using formation flying of small satellites. The individual satellites are broken down in five major subsystems: the spacecraft bus, the antenna design, the frontend, backend and data transport. One of the largest challenges is the inter satellite communication. In this paper the concept and design considerations of OLFAR are presented.

Theophylline intoxication can cause serious complications such as seizures, cardiac arrhythmias and eventually cardiac arrest. Because of these potentially life-threatening clinical manifestations of theophylline intoxication, treatment methods that rapidly eliminate the drug are essential. These methods include oral administration of activated charcoal and extracorporeal drug removal. Less life-threatening symptoms like refractory vomiting, that seriously interfere with the oral administration of activated charcoal may necessitate use of extracorporeal methods for drug removal as well. We present a case report on a 77-year-old female patient with theophylline intoxication who was treated by continuous venovenous haemofiltration because of refractory vomiting along with haemodynamic instability. Considering the better availability and good clinical efficacy of continuous venovenous haemofiltration in theophylline intoxication, this method may be considered if other methods of drug removal cannot be applied. Copyright © 2008, Nederlandse Vereniging voor Intensive Care. All Rights Reserved.