Many chloroplast genes are co-transcribed in polycistronic transcription units that give rise to numerous overlapping RNAs, but the significance of this pattern of transcript accumulation is not understood. An analysis of the transcripts of the adjacent and divergent maize psbE-psbF-psbL-ORF40 and ORF31-petE-ORF42 gene clusters indicates that transcription initiation at alternative promoters contributes to the generation of overlapping RNAs for both clusters. Furthermore, developmentally varying transcript ratios for the ORF31-petE-ORF42 gene cluster are determined at least in part by selective promoter usage. During light-induced plastid maturation, increased levels of primarily monocistronic petE transcripts accumulate from a promoter upstream of the internal petE gene. Dark-predominant and non-light-responsive bi- and tricistronic transcripts result from transcription initiation upstream of ORF31, the proximal gene of the cluster. In addition to the transcriptional overlap within gene clusters, divergent transcription units for the two gene clusters overlap and reciprocal antisense RNAs accumulate. The organization of the transcription units in this region raises the possibility of promoter interdependence or other functional interaction between transcription units.
Farmer adoption of practices to build soil health can be enhanced using a knowledge network supported by programs and resources that incorporate technical, social and experiential learning pathways. University Extension plays a critical role in building and supporting the knowledge network by serving as (a) a boundary organization to create space for conversations to occur, (b) network manager to facilitate learning and (c) builder of social capital to encourage trust in the network. The North Dakota State University (NDSU) Soil Health Program was used to illustrate the above approach. Between 2014 and 2016, 32 informal discussion groups, called Soil Health Café Talks, reached 156 individuals. A knowledge network of all participants was developed using NodeXL. The 10 most influential individuals in the network included two scientists, five farmers, one crop consultant and two Extension special-ists. All non-NDSU participants received an evaluation form. Respondents increased their frequency of discussing cover crops with other individuals and increased sharing equipment across farming operations (i.e., vertical tillage implements and no-till drills). Of the topics discussed, over 25% of respondents adopted practices using cover crops (interseeding and using cover crops for weed control and adjusting rotations to incorporate cover crops) as a result of attending Café Talks. Respondents also increased their use of NDSU Soil Health online resources such as Twitter (22%), YouTube (23%) and the web page (21%) as follow-up information to Café Talks.Network-based approaches have proven to be successful in encouraging on-farm adoption of soil health-building practices. K E Y W O R D Scollaborative, linear model, on-farm, whole systems
5.25 GHz, respectively. Measurements at other operating frequencies across the 2.4-and 5.2-GHz bands also show similar radiation patterns as shown in Figures 3 and 4, respectively, which indicates that the radiation patterns are stable in the two desired operating bands. Also notice that both the E and E components have comparable intensities. This characteristic is an advantage for the proposed antenna for WLAN or HIPERLAN operations, because their wave propagation environment is usually complex. In this case, comparable E and E radiation can decrease the effect of multiple-path fading and enhance the system performance. Figure 5 shows the measured antenna gain for frequencies across the lower and upper bands. The 2.4-GHz band has a peak antenna gain of about 2.8 dBi, and the gain variations are within about 1.3 dBi. On the other hand, the peak antenna gain of the 5.2-GHz band reaches about 3.1 dBi, and small gain variations (within about 0.5 dBi) are seen. CONCLUSIONSA novel low-cost, dual-band, surface-mountable monopole antenna has been proposed. The proposed antenna has two separate wide bandwidths covering the required bandwidths of WLAN (2.4-GHz band) and HIPERLAN (5.2-GHz band) systems. In addition, the proposed antenna is lightweight and can easily be constructed by folding a planar monopole made of a copper plate. Good radiation characteristics of the proposed antenna have also been observed.
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