Modeling Technical Change in Midwest Corn Yields, 1895-2005: A Time Varying-Regression Approach

This paper explores the use of time-varying regression models to model the effects of technical change in US Midwest Corn yields. The data extends from 1895 to 2005 encompassing the implementation of hybrid technologies and improvements in farm production practices.time-vary regression model, modeling technical change, corn yield technical change, Crop Production/Industries,

RCCZ4: A Reference Metric Approach to Z4

The hyperbolic formulations of numerical relativity due to Baumgarte, Shapiro, Shibata & Nakamura (BSSN) and Nagy Ortiz & Reula (NOR), among others, achieve stability through the effective embedding of general relativity within the larger Z4 system. In doing so, various elliptic constraints are promoted to dynamical degrees of freedom, permitting the advection of constraint violating modes. Here we demonstrate that it is possible to achieve equivalent performance through a modification of fully covariant and conformal Z4 (FCCZ4) wherein constraint violations are coupled to a reference metric completely independently of the physical metric. We show that this approach works in the presence of black holes and holds up robustly in a variety of spherically symmetric simulations including the critical collapse of a scalar field. We then demonstrate that our formulation is strongly hyperbolic through the use of a pseudodifferential first order reduction and compare its hyperbolicity properties to those of FCCZ4 and generalized BSSN (GBSSN). Our present approach makes use of a static Lorentzian reference metric and does not appear to provide significant advantages over FCCZ4. However, we speculate that dynamical specification of the reference metric may provide a means of exerting greater control over constraint violations than what is provided by current BSSN-type formulations.Comment: 19 pages, 18 figure

Tergitol enables the rapid and inexpensive scoring of nutritional and drug-resistance markers in the progeny of Neurospora crassa genetic crosses

After cultures from the progeny ascospores of a genetic cross containing nutritional markers are obtained, it is often necessary to test them on a variety of media. Testing using individual culture tubes may be ideal, but is time consuming. In contrast, inoculation of plates with conidial suspensions is relatively quick

Stability of Non-Minimally Coupled Topological-Defect Boson Stars

As shown by Marunovic and Murkovic, non-minimal d-stars, composite structures consisting of a boson star and a global monopole non-minimally coupled to the general relativistic field, can have extremely high gravitational compactness. In a previous paper we demonstrated that these ground-state stationary solutions are sometimes additionally characterized by shells of bosonic matter located far from the center of symmetry. In order to investigate the question of stability posed by Marunovic and Murkovic, we investigate the stability of several families of d-stars using both numerical simulations and linear perturbation theory. For all families investigated, we find that the most highly compact solutions, along with those solutions exhibiting shells of bosonic matter, are unstable to radial perturbations and are therefore poor candidates for astrophysically-relevant black hole mimickers or other highly compact stable objects.Comment: 19 pages, 24 figure

Ecophysiology of Marine Bivalves : Physiological Rate Processes in Dynamic Environments

Marine bivalves are globally recognized as ecologically and commercially valuable species and, for over a century, researchers have been studying their feeding, digestion and other related physiological processes. These studies have shown that marine bivalves have complex feeding and particle processing behaviors to maximize growth in dynamic environmental conditions. Additionally, these studies have provided insights into the ecological roles that these animals can play in coastal waters. Suspension-feeding bivalves are commonly regarded as providing key ecosystem services through their feeding activities that improve water quality and clarity. However, marine bivalves are currently under threat from a variety of anthropogenic effects and there is concern about their future health under these new stresses. Here I examined several unexplored aspects of adult and larval bivalve feeding physiology in an attempt to better understand environmental effects on their feeding activity and ecosystem services. In Chapter 2, my co-authors and I examined the ecological feeding physiology of native Olympia oysters Ostrea lurida by determining their feeding and particle processing behavior in response to the effects of temperature, salinity, and total particulate matter. We examined and compared these processes to those of the non-native yet dominant commercial oyster species, the Pacific oyster Crassostrea gigas. From these studies, we describe the first modern detailed feeding behavior of O. lurida. We found that, although markedly different in laboratory studies, in situ feeding rates were similar between these species seasonally. We concluded that bivalve filtration services are likely to be greater with the emergence of C. gigas as the now dominant species in many PNW estuaries and seasonally much greater than the services historically contributed by O. lurida. In Chapters 3, my co-authors and I examined the particle processing behavior of bivalve larvae. This study was novel in that it utilized methods of our own design to examine the rarely evaluated post-oral particle processing behavior of larvae that historically has been difficult to measure. Additionally, it represented the first attempt at modeling larval guts as chemical reactors to provide insights into their digestive strategies. In Chapter 4, we again applied these novel techniques to evaluate the effects of ocean acidification on ingestion rates and particle processing of larvae of the California mussel Mytilus californianus. These data were applied to a simple larval energy budget to understand how impacts of ocean acidification on initial larval development may affect their subsequent development rates. The outcomes of these experiments provide useful information on feeding and particle processing activities of the adult and larval life stages of marine bivalves and the effects of environmental factors, such as ocean acidification

Natural Nest-Site Characteristics of Two Small Forest Owls with Implications for Conservation and Management

Natural nest cavities of the Northern Saw-whet Owl (Aegolius acadicus) and the Northern Pygmy-Owl (Glacidium gnoma) were characterized using several variables measured from 79 nests. Northern Saw-whet Owls appear to prefer larger diameter trees, with larger cavity openings, and deeper cavities compared to the Northern Pygmy-Owls. Pygmy-owls also use a higher proportion of living trees with natural, i.e., not excavated, cavities compared to saw-whet owls. Tree height, nest height, and the number of cavities located on a snag were consistent between the two species. Internal examination of hundreds of cavities within owl territories shows that many cavities which appear appropriate for nesting owls are unusable. Leaving dead or dying trees for cavity nesting species is a common practice for forest managers in the West. However, criteria for “wildlife habitat” trees often adhere to a one-size-fits-all approach; retained cavities are selected based on external assessment alone. The dissimilarity in nest-site selection by these two species, and the fact that cavities show great variability in internal condition, underscore the need for forest managers to select a diverse array of trees for cavity nesting birds in western forests

Evaluation of Pt, Ni, and Ni–Mo electrocatalysts for hydrogen evolution on crystalline Si electrodes

The dark electrocatalytic and light photocathodic hydrogen evolution properties of Ni, Ni–Mo alloys, and Pt on Si electrodes have been measured, to assess the viability of earth-abundant electrocatalysts for integrated, semiconductor coupled fuel formation. In the dark, the activities of these catalysts deposited on degenerately doped p^+-Si electrodes increased in the order Ni < Ni–Mo ≤ Pt. Ni–Mo deposited on degenerately doped Si microwires exhibited activity that was very similar to that of Pt deposited by metal evaporation on planar Si electrodes. Under 100 mW cm^(−2) of Air Mass 1.5 solar simulation, the energy conversion efficiencies of p-type Si/catalyst photoelectrodes ranged from 0.2–1%, and increased in the order Ni ≈ Ni–Mo < Pt, due to somewhat lower photovoltages and photocurrents for p-Si/Ni–Mo relative to p-Si/Ni and p-Si/Pt photoelectrodes. Deposition of the catalysts onto microwire arrays resulted in higher apparent catalytic activities and similar photoelectrode efficiencies than were observed on planar p-Si photocathodes, despite lower light absorption by p-Si in the microwire structures

Long noncoding RNAs in liver cancer: what we know in 2014.

INTRODUCTION: Hepatocellular carcinoma (HCC) is the most common form of primary liver cancer with an estimated over half a million new cases diagnosed annually. Due to the difficulty in early diagnosis and lack of effective treatment options, HCC is currently ranked as the second highest neoplastic-related mortality in the world, with an extremely low 5-year survival rate of between 6 and 11%. Long noncoding RNAs (lncRNAs), are genes lacking protein coding ability, have recently emerged as pivotal participants in biological processes, often dysregulated in a range of cancers, including HCC. AREAS COVERED: In this review, we highlight the recent findings of lncRNAs in HCC pathogenesis, with particular attention on epigenetic events. In silico analysis was utilized to emphasize intrinsic linkages within the ncRNA families associated with hepatocarcinogenesis. EXPERT OPINION: While our understanding of lncRNAs in the onset and progression of HCC is still in its infancy, there is no doubt that understanding the activities of ncRNAs will certainly secure strong biomarkers and improve treatment options for HCC patients