Analysis and Design of Highly Transparent Meshed Patch Antenna Backed by a Solid Ground Plane

This paper analyzes rectangular and circular patch antennas fabricated from meshed conductors and backed with solid ground planes. Because of the meshing, the antennas are rendered optically transparent, where the transparency is determined by the mesh geometry. It is found that although there is a compromise between the antenna\u27s efficiency and the optical transparency of the meshed patch, it is possible to optimize the antenna by refining mesh lines to certain extent. The limiting factors for refining mesh lines include material handling and fabrication process as well as the increased line impedance when being refined, which accordingly causes loss in antenna\u27s efficiency or gain, it is seen that there is a limit for such an optimization method. This limit is closer to the efficiency of a solid patch for a lower transparency, whereas it is lower for increased transparency. Cross polarization level was also examined, and there was no significant effect on such a parameter due to meshing

Malaria, Intestinal Helminths and Other Risk Factors for Stillbirth in Ghana

Objective. The objective of the study was to assess Plasmodium/intestinal helminth infection in pregnancy and other risk factors for stillbirth in Ghana. Methods. A cross-sectional study of women presenting for delivery in two hospitals was conducted during November-December 2006. Data collected included sociodemographic information, medical and obstetric histories, and anthropometric measures. Laboratory investigations for the presence of Plasmodium falciparum and intestinal helminths, and tests for hemoglobin levels were also performed. Results. The stillbirth rate was relatively high in this population (5%). Most of the stillbirths were fresh and 24% were macerated. When compared to women with no malaria, women with malaria had increased risk of stillbirth (OR = 1.9, 95% CI = 1.2–9.3). Other factors associated with stillbirth were severe anemia, low serum folate concentration, past induced abortion, and history of stillbirth. Conclusion. The fact that most of the stillbirths were fresh suggests that higher quality intrapartum care could reduce stillbirth rates

Spatial distributions of oxygenated organic compounds (dicarboxylic acids, fatty acids, and levoglucosan) in marine aerosols over the western Pacific and off the coast of East Asia: Continental outflow of organic aerosols during the ACE-Asia campaign

Aerosol sampling for major oxygenated organic compounds (dicarboxylic acids, fatty acids, and levoglucosan) was conducted from 15 March to 19 April 2001 on board the National Oceanic and Atmospheric Administration R/V Ronald H. Brown over the western North Pacific, the East China Sea, and the Sea of Japan, as part of the Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia) campaign. During the cruise, aerosol particles were collected on quartz fiber filters using a high-volume air sampler. Diacids were also collected using an annular denuder sampling system to assess their gas-particle partitioning. Concentrations of total diacids, total fatty acids, and levoglucosan were found to be higher off the coasts of East Asia than in the remote Pacific. Contributions of these organic compounds to total organic carbon and total organic matter (OM) were calculated to be 9.8 ± 2.3% and 19.0 ± 4.8%, respectively, assuming OM to be organic carbon x 1.6. Diacid concentrations were highly correlated with nss-SO2-/4 and NO-3, which originate from anthropogenic sources over East Asia. The temporal variations and chain-length distributions of fatty acids suggest that atmospheric transport of terrestrial organic materials is important off the coast of the continent. C2 – C5 diacids were present predominantly in the particulate phase. The relative abundances of C2 – C5 diacids stayed almost unchanged throughout the cruise, suggesting that deposition is more important than chemical decomposition as a sink of diacids and that they are relatively stable end products in the atmosphere

Meta-analysis of human genome-microbiome association studies: The MiBioGen consortium initiative

Background: In recent years, human microbiota, especially gut microbiota, have emerged as an important yet complex trait influencing human metabolism, immunology, and diseases. Many studies are investigating the forces underlying the observed variation, including the human genetic variants that shape human microbiota. Several preliminary genome-wide association studies (GWAS) have been completed, but more are necessary to achieve a fuller picture. Results: Here, we announce the MiBioGen consortium initiative, which has assembled 18 population-level cohorts and some 19,000 participants. Its aim is to generate new knowledge for the rapidly developing field of microbiota research. Each cohort has surveyed the gut microbiome via 16S rRNA sequencing and genotyped their participants with full-genome SNP arrays. We have standardized the analytical pipelines for both the microbiota phenotypes and genotypes, and all the data have been processed using identical approaches. Our analysis of microbiome composition shows that we can reduce the potential artifacts introduced by technical differences in generating microbiota data. We are now in the process of benchmarking the association tests and performing meta-analyses of genome-wide associations. All pipeline and summary statistics results will be shared using public data repositories. Conclusion: We present the largest consortium to date devoted to microbiota-GWAS. We have adapted our analytical pipelines to suit multi-cohort analyses and expect to gain insight into host-microbiota cross-talk at the genome-wide level. And, as an open consortium, we invite more cohorts to join us (by contacting one of the corresponding authors) and to follow the analytical pipeline we have developed

Meshed Patch Antennas Integrated on Solar Cell - A Feasibility Study and Optimization

This thesis work presents the feasibility of integrating meshed patch antennas directly onto the solar cell assembly to save valuable surface real estate of a small satellite. The solar cell cover glass is used as the substrate for the patch antenna. The antenna topology is chosen to be a meshed patch so that it is transparent to light to ensure the proper operation of solar cells. We found that although there is a compromise between the antenna efficiency and see-through percentage, one is able to optimize the antenna by carefully designing the mesh. To verify the design and integration, a meshed antenna operating at around 2.3 GHz is printed with conductive ink on a plastic substrate and placed on-top of solar cells attached to an aluminum ground plane. The printed solar cell antenna is measured with Nearfield Systems Inc. spherical near-field range and the measurements agree well with the design

Integrated Optically Transparent Solar Cell Antennas Made from Meshed Conductors

This paper presents the feasibility of integrating meshed patch antennas directly onto the solar cell assembly to save valuable surface real estate of a small satellite. The solar cell cover glass is used as the substrate for the patch antenna. The integrated patch antennas are required to be transparent to light in order to ensure the proper operation of solar cells. It is found that the mesh geometry can be designed to offer the optimal transparency and antenna radiation at the same time. To design the transparent solar cell antennas in the presence of photovoltaic cells, Ansoft’s HFSS is used to model patch antennas on solar cells and the dielectric constant of solar cells is approximated with that of silicon.In order to verify the design, meshed antennas are printed with conductive ink on plastic substrate and measured results are compared against the design data from simulations

Integrated After-Market Solar Panel Antennas for Small Satellites

The majority of surface area on a small satellite is taken up by solar panels for power. Integrating antennas with solar panels, would save a valuable amount of satellite surface area, and thus directly contribute to the size reduction and multi-functionality of solar panel. Furthermore, such integration does not require deployed mechanism and therefore is cost-friendly design.Two types of integrations are presented in this paper. The first type is to place optically transparent antennas directly on top of after-market solar cells. Meshed conductors with optical transparency higher than 9 0% are used to design antennas in this case. The second type is to utilize the area between solar cells on the solar panel to design slot antennas. The slot antennas are highly integrative and lie on the same plane with the solar cells without blocking solar energy.The paper discusses both types of solar panel antennas that can be conveniently integrated with after-market solar cells, providing a novel and cost-friendly solution for small satellite system

Different rankers on different subcollections

Recent work has shown that when documents in a TREC ad hoc collection are partitioned, different rankers will perform optimally on different partitions. This result suggests that choosing different highly effective rankers for each partition and merging the results, should be able to improve overall effectiveness. Analyzing results from a novel oracle merge process, we demonstrate that this is not the case: selecting the best performing ranker on each subcollection is very unlikely to outperform just using a single best ranker across the whole collectio