Cell-free DNA fetal fraction in twin gestations in single-nucleotide polymorphism-based noninvasive prenatal screening

Objectives

The performance of noninvasive prenatal screening (NIPS) for fetal aneuploidy in twin pregnancies is dependent on the amount of placentally derived cell-free DNA, the “fetal fraction (FF),” present in maternal plasma. We report FF values in monozygotic (MZ) and dizygotic (DZ) pregnancies.

Methods

We reviewed FF in pregnancies at 10 to 20 completed weeks gestational age based on single-nucleotide polymorphism (SNP)-based NIPS where zygosity was routinely established in twin pregnancies. The cohort included 121 446 (96.3%) singleton, 1454 (1.2%) MZ, and 3161 (2.5%) DZ pregnancies. For DZ twins, individual FFs were measured.

Results

Combined FF for DZ and MZ fetuses were 35% and 26% greater than singletons, respectively. The individual FF contributions from each fetus in DZ twins were, on average, 32% less than singletons. FF in DZ twin pairs were moderately correlated (Pearson correlation coefficient.66). When a threshold of 2.8% FF was applied to define uninterpretable results, 1.7% (2102/121 446) of singletons, 0.8% (11/1454) of MZ pairs, and 5.6% (178/3161) of DZ pairs were uninterpretable.

Conclusion

For optimal aneuploidy NIPS in twin pregnancies, zygosity should be established and in DZ twins FF for both fetuses should be determined to identify those cases where results can be reliably interpreted.     

Comparative floorplan-analysis as a means to develop design guidelines

This study explores the usefulness of comparative floorplan-analysis for the development of spatio-organizational concepts in architectural design processes.Each floorplan can be considered as a reflection of the goals and activities of the users as interpreted by the architect. By comparing a wide range of building layouts for similar organizations one may achieve a good understanding of the way organizational characteristics are (can be) expressed in spatial solutions. In the study reported here, in which 50 Dutch health centres were analysed comparatively, definite relationships between organizational and spatial concepts were found. This information is used both as a means to make organizational principles more explicit as well as data for briefwriting and design guidelines.     

Temporal and spatial changes in primary biomass as a diagnosis and prognosis in environmental impact (Rapel Reservoir,Central Chile)

Extensive mortality of silversides (Atherinidae), Odontesthes bonariensis, was recorded during July 1989 in the Rapel Reservoir. Temporal and spatial changes observed in biomass concentration (chlorophyll-a) through both ground and remote sensing samples (LANDSAT), allowed us to establish a potential environmental impact. Ground measurements established an input of sulfate (SO₄) in a eutrophic area. The mean concentration of biomass tended to decrease in this area in comparison with other mesotrophic areas. The local disfunction associated with the observed biomass changes has been used to develop a prediction in species composition and in biomass concentration.

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Resumen Durante la primera semana de Julio de 1989, se registró una muerte masiva de pejerreyes, Odontesthes bonariensis en el Embalse Rapel. En los procesos de monitoreo de la calidad de agua en el Embalse Rapel, se utilizó una representacion espacial primaria de las variables de estado elegidas. Las tendencias témporo-espaciales observadas en la concentración de biomasa fitoplanctónica (clorofila-a) permitieron establecer un impacto ambiental potencial por un agente exógeno al sistema. A partir de mediciones de terreno se estableció la presencia de sulfato (SO₄) en una zona de características eutróficas. Los efectos observados en esta zona, en comparación al resto del embalse, fueron una disminución en la concentración media de la biomasa. La disfunción local observada, permitió sustentar una prognosis asociada a la composición de especies fitoplanctónicas y la concentración de biomasa local.

     

MANAGEMENT OF WATER QUALITY IN RELEASES FROM SOUTHWESTERN IMPOUNDMENTS1

ABSTRACT. The objective of this investigation was to determine the selectivity of withdrawal which is possible in southwestern reservoirs. Two stratified flow solutions were examined to test their applicability under field conditions. Although both appeared capable of accurate prediction of the outflow velocity profile, the Bohan-Grace solution, which required less input data, was utilized to predict the chemical constituents of single and simultaneous releases from several southwestern impoundments. Prediction of outflow water quality was within fifteen percent for southwestern reservoirs as shallow as fifty-five feet. The withdrawal layer thickness for the subject Texas impoundments included the entire hypolimnion or epilmnion depending on outlet location. The sensitivity of the velocity profile to seasonal changes, reservoir discharge rate and withdrawal port dimensions also is illustrated.     

A multilevel model of emotional skills,communication performance,and task performance in teams

There is increasing research regarding the influence of emotions on teamwork. In this study, we use a multilevel approach to examine how team members' use of emotion‐related skills affects team task performance and communication performance within the team. We measured individual self‐reported emotional skills prior to team formation and then collected peer‐rated individual communication performance and independently rated team task performance eight weeks later. Although there was no influence at the individual level between emotional skills and performance, team‐level emotional skills positively predicted team task performance scores. At the cross level, team‐level emotional skills predicted individual‐level communication performance. These findings emphasize the importance of distinct team emotional skills in shaping both team performance and individual team member performance. Copyright © 2011 John Wiley & Sons, Ltd.     

Nitrogen fluxes on an intensive investigation plot in the North Tyrolean limestone Alps

In the framework of this study, nitrogen fluxes on a limestone site are investigated. The major goals are the assessment of the nitrogen status, the estimation of the nitrogen budget and the evaluation of the nitrogen saturation. The investigation area, the intensive investigation plot and the research equipment are described.     

Monitoring the impact of sulphur with the Austrian Bioindicator Grid

In Austria, the impact of sulphur has been assessed since 1985 with the help of the Austrian Bioindicator Grid on 760 sample plots with Picea abies as the main tree species (90%). The annual sampling allows a precise evaluation of the temporal and regional development of the impact of sulphur on the basis of legal standards. Despite the reduction of SO2 emissions in Austria, the legal standard is still exceeded on 8% of the plots. These plots are mainly located near large Austrian emittors, but also in areas affected by transboundary sulphur emissions from neighbouring countries. The present paper describes how the Bioindicator Grid can be applied for the control of legal requirements to enact effective clean air measures in Austria and take supportive measures that reduce the impact of sulphur from emittors in neighbouring countries.