How Land Use Shapes the Evolution of Road Networks

The present research develops an agent-based model to treat the organization, growth, and contraction of network elements. The components model travel demand, revenue, cost, and investment. Revenue earned by links in excess of maintenance costs is invested on the link to until all revenue is consumed. After upgrading (or downgrading) each link in the network, the time period is incremented and the whole process is repeated until an equilibrium is reached or it is clear that it cannot be achieved. The model is tested with three alternative land use patterns: uniform, random, and bell-shaped, to test the effects of land use on resulting network patterns. It is found that similar, but not identical, equilibrium hierarchical networks result in all cases, with the bell-shaped network, with a CBD, having higher level roads concentrated in a belt around the CBD, while the other networks are less concentratedSelf-organization, network growth, network evolution, transportation planning, land use planning

Highway Costs and the Efficient Mix of State and Local Funds

Transportation networks and governments are both hierarchically organized. In some states most highways are financed by state governments, while in other states similar roads are financed locally. Larger governments attain scale economies. However they also tend to be more bureaucratic and have higher operating costs, all else equal, due to problems such as span of control. This study relates highway expenditure with share of expenditure by state government so that a basis for determining how governments should share expenditure on all roads in a state to attain efficiency in highway costs. For each state three different costs are considered: capital outlay, operations and maintenance, and total costs. Two government layers are considered: state (including federal contributions) and local government. A series of regression models to predict different highway expenditures as a function of utilization, capacity, and funding shares are estimated. We find that there is a share of expenditures by each level of government which results in a minimum expenditure for each funding category (capital, operating). That minimum is not very far from typical state/local mixes found in many states. The results of this study can be applied in formulation of efficient network financing arrangements. Policies can be formulated that can help adjust the financial responsibilities of transportation networks between government layers. Transportation Research Record:

A Note on Gauss-Bonnet Black Holes at Criticality

With in the extended thermodynamics, we give a comparative study of critical heat engines for Gauss-Bonnet and charged black holes in AdS in five dimensions, in the limit of large Gauss-Bonnet parameter $\alpha$ and charge $q$, respectively. We show that the approach of efficiency of heat engines to Carnot limit in Gauss-Bonnet black holes is higher(lower) than charged black holes when corresponding parameters are small(large).Comment: 14 pages, 17 figure

A study of Tesla\u27s Financial Strategy since the Great Recession

During the Great Recession of 2008, Tesla Motors nearly collapsed and was later rescued with low interest loans provided by the U.S. government in 2009. This research paper evaluates the company’s financial strategies that lead to its rescue, and studies its current financial position in the market. This includes the financial consequences of the recession on Tesla from 2008 to 2009. The company was down to its last $9 million in cash in 2009, sold 937 cars and lost$31.5 million. In early 2010, Tesla finally decided to file for IPO for a $100 million offering. Tesla has since invested in its Model S electric sedan to generate profits upon delivery; however its stock has seen remarkable volatility since then. Tesla’s financials are analyzed over the years and compared with an evaluation of its current market position

RELATIONSHIP BETWEEN MORPHOGENESIS AND SECRETION IN THE FILAMENTOUS FUNGUS \u3ci\u3eASPERGILLUS NIDULANS\u3c/i\u3e

Filamentous fungi have a long history in biotechnology for the production of food ingredients, pharmaceuticals and enzymes. The advancements made in recent years have earned filamentous fungi such as Aspergillus species a dominant place among microbial cell factories. Although the model fungus A. nidulans has been extensively studied, the genetic and regulatory networks that underlie morphogenesis and development have yet to be fully characterized. The Rho GTPases (Cdc42 and RacA) are one of the most important regulators of the morphogenetic processes among diverse eukaryotic organisms. Although the functions of these GTPases are relatively well-characterized, little is known about their downstream effectors. One likely effector is the formin SepA, which also belongs to a complex known as the polarisome that helps to stabilize and support hyphal growth. The uncharacterized gene ANID_05595.1 (ModB) possesses sequence features that suggest it also belongs to the polarisome. My genetic and functional characterization of ModB reveals some overlap with SepA, but also shows that ModB possesses distinct roles in the maintenance of hyphal polarity. In filamentous fungi, hyphal morphology requires the localized delivery of exocytic vesicles to the hyphal tip as well as to septation sites. The mechanisms that regulate vesicle trafficking to these locations are not yet well understood. In addition, because fungal hyphae presumably extend through a nutritionally variable environment, these mechanisms must be extremely sensitive to growth conditions. To begin to address these issues, I have investigated the effects of nutrient conditions on localization patterns of two different proteins that are trafficked to the cell surface; a glucose transporter (HxtB) and the enzyme β-glucosidase (BglA). Although the final localization of each protein differs, they display similar localization dynamics upon release from glucose repression. In parallel, I also used fluorescence microscopy to determine how shifts from glucose to a non-preferred carbon source (e.g., cellulose) affect hyphal extension and morphology. My results suggest that relief from glucose repression leads to the production of thinner hyphae after a transient delay in hyphal extension. Use of variety of signaling mutants further demonstrates that this response requires a functional protein kinase A (PKA) as well as proper down-regulation of heterotrimeric G protein signals. Collectively, these observations provide valuable new insight into how vesicle trafficking responds to variable growth conditions. Advisor: Steven D. Harri