Life Cycle Characteristics of Warm-Season Severe Thunderstorms in Central United States from 2010 to 2014

Weather monitoring systems, such as Doppler radars, collect a high volume of measurements with fine spatial and temporal resolutions that provide opportunities to study many convective weather events. This study examines the spatial and temporal characteristics of severe thunderstorm life cycles in central United States mainly covering Kansas, Oklahoma, and northern Texas during the warm seasons from 2010 to 2014. Thunderstorms are identified using radar reflectivity and cloud-to-ground lightning data and are tracked using a directed graph model that can represent the whole life cycle of a thunderstorm. Thunderstorms were stored in a GIS database with a number of additional thunderstorm attributes. Spatial and temporal characteristics of the thunderstorms were analyzed, including the yearly total number of thunderstorms, their monthly distribution, durations, initiation time, termination time, movement speed and direction, and the spatial distributions of thunderstorm tracks, initiations, and terminations. Results revealed that thunderstorms were most frequent across the eastern part of the study area, especially at the borders between Kansas, Missouri, Oklahoma, and Arkansas. Finally, thunderstorm occurrence is linked to land cover, including a comparison of thunderstorms between urban and surrounding rural areas. Results demonstrated that thunderstorms would favor forests and urban areas. This study demonstrates that advanced GIS representations and analyses for spatiotemporal events provide effective research tools to meteorological studies

Exploring transcriptional signalling mediated by OsWRKY13, a potential regulator of multiple physiological processes in rice

BACKGROUND Rice transcription regulator OsWRKY13 influences the functioning of more than 500 genes in multiple signalling pathways, with roles in disease resistance, redox homeostasis, abiotic stress responses, and development. RESULTS To determine the putative transcriptional regulation mechanism of OsWRKY13, the putative cis-acting elements of OsWRKY13-influenced genes were analyzed using the whole genome expression profiling of OsWRKY13-activated plants generated with the Affymetrix GeneChip Rice Genome Array. At least 39 transcription factor genes were influenced by OsWRKY13, and 30 of them were downregulated. The promoters of OsWRKY13-upregulated genes were overrepresented with W-boxes for WRKY protein binding, whereas the promoters of OsWRKY13-downregulated genes were enriched with cis-elements putatively for binding of MYB and AP2/EREBP types of transcription factors. Consistent with the distinctive distribution of these cis-elements in up- and downregulated genes, nine WRKY genes were influenced by OsWRKY13 and the promoters of five of them were bound by OsWRKY13 in vitro; all seven differentially expressed AP2/EREBP genes and six of the seven differentially expressed MYB genes were suppressed by in OsWRKY13-activated plants. A subset of OsWRKY13-influenced WRKY genes were involved in host-pathogen interactions. CONCLUSION These results suggest that OsWRKY13-mediated signalling pathways are partitioned by different transcription factors. WRKY proteins may play important roles in the monitoring of OsWRKY13-upregulated genes and genes involved in pathogen-induced defence responses, whereas MYB and AP2/EREBP proteins may contribute most to the control of OsWRKY13-downregulated genes.This work was supported by grants from the National Program of High Technology Development of China, the National Program on the Development of Basic Research in China, and the National Natural Science Foundation of China

Design and modeling of a CMOS VCO using wave digital filters / by WeiBo Li.

Wave digital filters (WDFs) transform an analog network into a topologically equivalent digital structure. A natural application of WDF is the simulation of electric circuits since measurements of any desired node voltages and branch currents are available during all time-steps in WDF structures. WDF structures tend to preserve most of the good properties of their analog counterpart. In this work, WDF techniques applied to transient simulation are studied. After a review o f the basic theory of WDFs and the treatment of nonlinear elements in WDFs, WDF simulations for different circuits, including a simple RC circuit, an anharmonic oscillator and a CMOS LC voltage controlled oscillator (VCO), are presented. Special detail is put on the design and modeling of the LC VCO. The LC VCO was designed and fabricated using the TSMC (Taiwan Semiconductor Manufacturing Co., LTD) CMOS 0.1 Sum technology. The linear frequency tuning range of the LC VCO is from 2.526 GHz to 3.015 GHz for control voltages from 0 to 1 V with a 1.712 mA tail current. WDF simulation results are compared with the exact solution if possible or otherwise with the results obtained with other simulation methods. The comparison shows that WDF techniques are efficient for the simulations of linear circuits and circuits with one nonlinear element. The potential of WDF for the simulation of large networks with many nonlinear elements is also discussed in this thesis

High-efficiency generation of nanoscale single silicon vacancy defect array in silicon carbide

Color centers in silicon carbide have increasingly attracted attention in recent years owing to their excellent properties such as single photon emission, good photostability, and long spin coherence time even at room temperature. As compared to diamond which is widely used for holding Nitrogen-vacancy centers, SiC has the advantage in terms of large-scale, high-quality and low cost growth, as well as advanced fabrication technique in optoelectronics, leading to the prospects for large scale quantum engineering. In this paper, we report experimental demonstration of the generation of nanoscale $V_{Si}$ single defect array through ion implantation without the need of annealing. $V_{Si}$ defects are generated in pre-determined locations with resolution of tens of nanometers. This can help in integrating $V_{Si}$ defects with the photonic structures which, in turn, can improve the emission and collection efficiency of $V_{Si}$ defects when it is used in spin photonic quantum network. On the other hand, the defects are shallow and they are generated $\sim 40nm$ below the surface which can serve as critical resources in quantum sensing application

A Mode Choice Study on Shared Mobility Services: Policy Opportunities for a Developing Country

This research aims to investigate the mode choice behaviour associated with bike-sharing and car-sharing, and the strategies for encouraging their demand in order to pull people away from using private cars. In particular, we reveal the factors that could affect the choices of both services and explore their associated modal substitution patterns. Key interests are put on air pollution’s impact on bike-sharing choice and the sources of demand for car-sharing (i.e. from private car users or public transport users). Moreover, we look at in what ways attitudinal factors could influence shared mobility choices and hence identify any implications. Furthermore, we are also interested in any measures from the habitual level that may help control private car usage in addition to the tactical-level efforts. The mode choice and related data employed in this work were collected by a paper-based questionnaire survey launched in 2015 at a Chinese city. Discrete choice modelling techniques are extensively applied, including the mixed logit (ML), mixed nested logit (mixed NL) and integrated choice and latent variable (ICLV) models. Our findings are compared to those from developed countries for any similarities and differences that lie between, though by addressing several key research gaps in the field, the findings will also significantly enrich the literature on shared mobility choice behaviour as well as disclosing implications for practitioners from both developed and developing countries for take-away and formulating the corresponding demand management policies

Graph-based representation and analysis for storm events

This presentation was given as part of the GIS Day@KU symposium on November 18, 2015. For more information about GIS Day@KU activities, please see http://www.gis.ku.edu/gisday/2015/.Platinum Sponsors: KU Department of Geography and Atmospheric Science; KU School of Business. Gold Sponsors: Bartlett & West; Kansas Biological Survey; KU Environmental Studies Program; KU Institute for Policy & Social Research; KU Libraries. Silver Sponsors: State of Kansas Data Access and Support Center (DASC). Bronze Sponsors: KU Center for Remote Sensing of Ice Sheets (CReSIS); TREKK Design Group, LLC; Wilson & Company, Engineers and Architects

Facing alternative futures: prospects for and paths to food security in Africa

"Food security in Africa has substantially worsened since 1970. Although the proportion of malnourished individuals in Sub-Saharan Africa has remained in the range of 33–35 percent since around 1970, the absolute number of malnourished people in Africa has increased substantially with population growth, from around 88 million in 1970 to an estimate of over 200 million in 1999–2001. Yet this discouraging trend need not be a blueprint for the future. New research from IFPRI shows that the policy and investment choices of African policymakers and the international development community can make an enormous difference for Africa's future agricultural production and food security. By modeling the results of a number of different policy scenarios in Africa through the year 2025, we show that the number of malnourished children, one important indicator of food security, could rise as high as 41.9 million or fall as low as 9.4 million. These scenarios, therefore, shed light on the effectiveness of various policies and investments in assuring a food-secure future for Africa.' from TextFood insecurity, Forecasting, Agricultural productivity, Human capital, Malnutrition in children, Impact model,