Potential vorticity index

Based on the European Center For Medium Range Weather Forecasting (ECMWF) First Global Atmospheric Research Program Global Experiment (FGGE) IIIb data set in the 1978 to 1979 winter, a potential vorticity (PV) index was defined as a measure of the zonally averaged, mid-latitude PV gradient on the 300 K isentropic surface in the Northern Hemisphere. The evolution of that index and its relation to teleconnection patterns of 500 mb geopotential height anomaly are studied. The results of the temporal and spatial variation of blocking and cyclogenesis in the 1978 to 1979 winter and its relation to global and local PV gradients were obtained. Complex empirical orthogonal function (EOF) analyses were performed, using the same FGGE data set for the 1978 to 1979 winter, for a representative high latitude band and mid latitude band geopotential height anomalies at 500 mb, phi sub h, phi sub m, and PV gradient at 300 K, delta(Q), at each longitude for the three month period. The focus of current research is the following: (1) to perform Fourier analyses for the first three EOF's of phi sub h, phi sub m, and delta(Q) at given latitude bands, and to find the dominant wavenumbers and frequencies which are responsible for these EOF's; (2) to compare the results from EOF and Fourier analyses which will be used to explore the relations of blocking and cyclogensis with local and global PV gradients; and (3) to study the time dependence of the local PV gradients and relate it to the PV index vacillation cycles observed in the PV index cycle

Engaging audiences through social media in colleges of agricultural and environmental sciences

Seventy percent of Americans use social media to connect with one another, share information and entertain themselves (Pew, 2019). Of those connecting socially, it's estimated 79% of 18-29-year olds are using Facebook and 38% are using Twitter. With college students being active on social media, college departments are able to leverage these many platforms to engage with students meaningfully. What is not clear, is what are the most successful tactics these departments are using. The objectives of this study were to 1) understand how departments within a college of agriculture and natural resources use Twitter and Facebook to engage audiences, 2) determine the success of tactics based on the highest levels of engagement, and 3) understand whom popular posts are targeting. For this study, researchers gathered 16 months of analytical information from 4 academic departments. The top 5 Twitter posts from each month per department were used to determine the average number of impressions, engagements, and the overall engagement. For Facebook, the lifetime of a post's total reach and lifetime of engaged users were averaged. Tactics noted included if the post had a photo, video, link, hashtag, or tagged another page. The audience of each post was analyzed to track popular themes. For Twitter, 307 tweets were analyzed across 4 departments. The departments had 608 total engaging elements, while on Facebook, 303 posts were analyzed for 493 total engaging elements across departments. Results show departments are engaging with three main audiences: students, faculty/staff, and alumni. Posts with engaging elements of images and videos had higher levels of user engagement in all departments. Popular themes across platforms include students on campus, student organizations, research, and events. This study aligned with most previous social media research in that posts with engaging elements have more reach. It is important that departments continue to use such tactics to reach audiences.No embargoAcademic Major: Agricultural Communicatio

Significance of rice sheath photosynthesis: Yield determination by 14C radio-autography.

Using high-yielding hybrid rice Liangyopeijiu (LYP9), its male parent 9311 and hybrid rice Shanyou 63 (SY63) as the experimental materials, the photosynthesis of rice sheath was studied by 14C radio-autography. The results showed that rice sheath could trap sunlight and produce photosynthates, and these photosynthates were transported mainly to the spikes. The 14C-labeled photosynthates transported to the spikes of LYP9 and 9311 were significantly more than those of SY63 after 72 hr, which indicated that differences among genotypes existed for contribution rates of sheath photosynthesis to economical yield. Transport of the 14C-labeled photosynthates to the spikes was faster in the sheaths of LYP9 than in those of 9311and SY63 at 12 and 72 hr after treatment. Hybrid rice housed the heterosis and were influenced by the inheritable characters of its parents. Since photosynthesis of rice sheath is an important supplement to rice yield, inefficient photosynthesis in rice sheaths could cause serious yield reduction.Key Words: Hybrid rice, photosynthates, spike

Electro-optically tunable low phase-noise microwave synthesizer in an active lithium niobate microdisk

Photonic-based low-phase-noise microwave generation with real-time frequency tuning is crucial for a broad spectrum of subjects, including next-generation wireless communications, radar, metrology, and modern instrumentation. Here, for the first time to the best of our knowledge, narrow-bandwidth dual-wavelength microlasers are generated from nearly degenerate polygon modes in a high-Q active lithium niobate microdisk. The high-Q polygon modes formation with independently controllable resonant wavelengths and free spectral ranges is enabled by the weak perturbation of the whispering gallery microdisk resonators using a tapered fiber. The stable beating signal confirms the low phase-noise achieved in the tunable laser. Owing to the high spatial overlap factors between the two nearly degenerate lasing modes as well as that between the two lasing modes and the pump mode, gain competition between the two modes is suppressed, leading to stable dual-wavelength laser generation and in turn the low noise microwave source. The measured microwave signal shows a linewidth of ~6.87 kHz, a phase noise of ~-123 dBc/Hz, and an electro-optic tuning efficiency of -1.66 MHz/V.Comment: 13 pages, 5 figure

Simple and robust downstream purification process for cell-derived influenza vaccines

New emerging influenza viruses with pandemic potentials were occurred in recent years, e.g. H5N1 in 1997, H1N1 in 2009, and H7N9 in 2013. The demand of producing pandemic influenza vaccines for human use with quick supply is high. For the cell-based pandemic influenza vaccines, we proposed a flow-through chromatography purification process. This process has only involved few purification steps and is easy to operate. Vero- and MDCK- cell derived avian influenza viruses including H5N1 and H7N9 were purified efficiently by the process proposed. The presented purification process consisted of clarification, inactivation, concentration, anion exchange chromatography (Capto Q), size exclusion and adsorption chromatography (Capto Core 700), diafiltration and sterile filtration. In the chromatography steps, cell DNA and protein were removed remarkably, and the virus were flowed through these columns. The flow rate was set as fast as 250 cm/min. The loading volume of virus solution was up to 50 times of column volume (CV).The DNA was removed over 90% after using Capto Q column, and was further removed by Capto Core 700 column. The overall removal rate of cellular DNA was more than 99%. The HA recovery rates of H5N1 and H7N9 influenza virus from Vero and MDCK cells were 20 to 40%. The DNA concentration of all purified bulks met the regulatory requirement of 10ng per dose. The developed purification process is simple and efficient, and it is suitable for purification of various influenza virus strains and can be used for the pandemic influenza vaccine production