Molecular First Hyperpolarizabilities of a New Class of Asymmetric Squaraine Dyes

The molecular first hyperpolarizabilities (β) of a series of asymmetric squaraine dyes have been measured by electric-field-induced second harmonic generation; the dyes have negative β-values whose magnitudes are comparable to 4-N,N-dimethylamino-4′-nitrostilbene (DANS)

Regulation of the Cdc14-like Phosphatase CLP1 in \u3cem\u3e Schizosaccharomyces pombe\u3c/em\u3e and Identification of SID2 Kinase Substrates: A Dissertation

Coordination of mitosis and cytokinesis is crucial to generate healthy daughter cells with equal amounts of genetic and cytoplasmic materials. In the fission yeast Schizosaccharomyces pombe, an evolutionarily conserved Cdc14-like phosphatase (Clp1) functions to couple mitosis and cytokinesis by antagonizing CDK activity. The activity of Clp1 is thought to be regulated in part by its subcellular localization. It is sequestered in the nucleolus and the spindle pole body (SPB) during interphase. Upon mitotic entry, it is released into the cytoplasm and localized to the kinetochores, the actomyosin ring, and the mitotic spindle to carry out distinct functions. It is not clear how Clp1 is released from the nucleolus, however, once released, a conserved signaling pathway termed Septation Initiation Network (SIN) functions to retain Clp1 in the cytoplasm until completion of cytokinesis. The SIN and Clp1 function together in a positive feedback loop to promote each other’s activity. That is, the SIN promotes cytoplasmic retention of Clp1, and cytoplasmic Clp1 antagonizes CDK activity and reverses CDK inhibition on the SIN pathway to promote its function and activity. However, at the start of this thesis, the mechanism by which the SIN regulated Clp1 was unknown. The SIN pathway is also required to promote constriction of the actomyosin ring, and the septum formation. However, its downstream targets were still uncharacterized. In two separate studies, we studied how Clp1 is released from the nucleolus at mitotic entry and how the SIN kinase Sid2 acts to retain Clp1 in the cytoplasm. We identified several Sid2 candidate substrates, and revealed other functions of the SIN pathway in coordinating mitotic events

Environmental Regulation of Hog Feeding Operations

THE US livestock industry has experienced drastic structural changes over the last two decades. The industry has shifted towards greater specialization across production phases, increased reliance on off-farm inputs such as feed, and increased use of production contracts (McBride and Key 2013). One trend that is particularly relevant to Iowa policymakers, farmers, and rural Iowans is the increased prevalence, size, and regional intensity of large, enclosed hog feeding operations. Where many of the largest hog-producing states have seen modest increases or even declines in total hog inventories over time, Iowa has seen a steady increase in inventories since 1982 (Figure 1a). Within Iowa, production concentrates in north-central and northwestern counties (Figure 1b)

A Fortune from Misfortune: Evidence from Hog Firms’ Stock Price Responses to China’s African Swine Fever

China is the world’s largest pork producer and a leading pork importer. Since Au- gust 2018, ongoing outbreaks of African Swine Fever (ASF), a highly contagious and deadly disease affecting pigs, have hit China’s livestock industries and wiped out 40% of China’s pigs. We leverage data on daily stock returns from 25 major publicly listed firms from China and eight major pork-exporting countries to provide the first systematic analysis of the firm-level economic impacts of the outbreaks. We find that on average announcements of ASF outbreaks have led to positive and significant stock returns for both Chinese and international hog companies. Notably, Chinese hog companies on average enjoyed 10%–40% of cumulative abnormal returns during the 2019 Chinese Spring Festival, a peak demand season for pork. We show that larger hog firms tend to capture greater positive stock returns. Our results suggest opportunities for consolidation, expansion, and upgrades of China’s meat industry that have long-run implications for its global competitiveness and efficiency

Identification using Valanis model for beams with nonlinear bolted joint and boundary connection

Bolted joints are widely applied in assembled mechanical structures. This paper focuses on the nonlinear modeling and parameter identification of bolted beams. Two Valanis models are respectively used to describe the nonlinear behaviors of the bolted joint and the boundary connection. Experimental tests at low and high excitation levels are performed to reveal the dynamic characteristics of the bolted beams. The Young’s modulus of the beams is identified via experimental test with low excitation level; whereas the parameters of Valanis model are identified by using optimization technique in order to minimize the residual error between the measured and the simulation data at a high excitation level