Rental Housing and the Natural Vacancy Rate

This study uses 1989-2005 data for the Seattle metropolitan area to test the natural vacancy rate hypothesis for rental housing markets using a new methodology. Findings support the existence of a natural vacancy rate for apartments that varies over time, and in some cases across apartment submarkets. Results show a decline in the natural vacancy rate in the time period following the introduction and growth of the Web. Results also show significant differences in natural vacancy rates for different geographic subareas. No significant differences in the natural vacancy rate are found for different apartment types.

Improving Energy Efficiency and Motion Control in Load-Carrying Applications using Self-Contained Cylinders

Because of an increasing focus on environmental impact, including CO2 emissions and fluid spill pollution, inefficient hydraulic systems are being replaced by more environmentally friendly alternatives in several industries. For instance, in some offshore applications that have multiple diesel generators continuously running to produce electricity, all hydraulic rotating actuators supplied from a central hydraulic power unit have been replaced with AC induction motors containing a variable frequency drive and gearbox. However, hydraulic linear actuators are still needed in most load-carrying applications mainly because of their high reliability associated with external impact shocks. Moreover, their force capacity is higher than that of their linear electromechanical counterparts. Valve-controlled linear actuators (cylinders) supplied from a centralized hydraulic power unit are standard in offshore load-carrying applications. In addition to the advantages mentioned above of hydraulic linear actuators, they have, nevertheless, a number of important drawbacks, which include: 1) a high level of energy consumption due to significant power losses caused by flow throttling in both the pipelines and valves, 2) reduced motion performance due to the influence of load-holding valves, 3) high CO2 emissions and fuel costs related to the diesel generator that supplies electricity to the hydraulic power unit, 4) significant potential for hydraulic fluid leakage because of many leakage points, 5) demanding efforts with respect to installation and maintenance, as well as 6) costly piping due to the centralized hydraulic power supply. The work presented in this dissertation and the appended papers are devoted to replacing inefficient hydraulic linear actuation systems traditionally used in offshore load-carrying applications with more environmentally friendly solutions. Two alternative technologies are identified, namely electro-mechanical and electro-hydraulic self-contained cylinders. The feasibility of replacing conventional valve-controlled cylinders with self-contained cylinder concepts is investigated in two relevant case studies.publishedVersio

Use of Capacitance Sensors for Development of Conservative Irrigation Regimes

Several experiments were conducted to further develop capacitance sensor-based automated irrigation systems. The first experiment tested whether the photosynthetic response to decreasing volumetric water content (VWC) differed among four species tested. A sigmoidal curve best described the relationship for all species (r2 [r-squared]\u3e0.86). The VWC that maintained maximum photosynthesis at 90% was selected as a potential conservative irrigation set point and values were not different between species, nor were 100% container capacity values. This indicates that a single set point is adequate to initiate irrigation and that a common upper threshold for VWC can be used for this group of taxa. This research also examined which of five sensor placements best estimates VWC and the effect of low VWC on sensor reading variability. Five sensor placements were tested; three sensors were horizontally inserted into the sidewall at 5 cm, 10 cm and 15 cm from the base of the container. The other two placements, vertical and diagonal, were inserted into the substrate surface. All positions showed a strong linear relationship (r2[r-squared]\u3e0.92) making them all appropriate models of container substrate moisture. No placement proved better than the others, but choosing a vertical placement is most practical for sensor calibration, installation, and removal. Other trials were conducted to test two container nursery irrigation regimes on oakleaf hydrangea (Hydrangea quercifolia ‘Alice’) in both nursery and greenhouse environments. Plants were automatically irrigated by one of two substrate moisture sensor-based regimes: 1) a daily water use (DWU) system that delivered the exact amount of water lost in the previous 24 h and 2) an on-demand (OD) irrigation system based on the relationship between substrate moisture level and photosynthetic rate. In this system, irrigation was applied when the substrate moisture level fell below 33% container capacity, which corresponded to 90% maximum predicted photosynthetic rate. Both treatments used significantly less water than the industry standard of 2.5 cm/day. This research demonstrated that automating irrigation based on the relationship between photosynthesis and VWC may be practical for multiple species in a nursery setting and can attenuate water use to meet crop demands

Cubulating hyperbolic free-by-cyclic groups: the general case

Let $\Phi:F\rightarrow F$ be an automorphism of the finite-rank free group $F$. Suppose that $G=F\rtimes_\Phi\mathbb Z$ is word-hyperbolic. Then $G$ acts freely and cocompactly on a CAT(0) cube complex.Comment: 36 pages, 11 figures. Version 2 contains minor corrections. Accepted to GAF

A method for smoothly disengaging the load-holding valves of energy-efficient electro-hydraulic systems

publishedVersio

Hsp90-binding immunophilins link p53 to dynein during p53 transport to the nucleus

The tumor suppressor protein p53 is known to be transported to the nucleus along microtubular tracks by cytoplasmic dynein. However, the connection between p53 and the dynein motor protein complex has not been established. Here, we show that hsp90.binding immunophilins link p53.hsp90 complexes to dynein and that prevention of that linkage in vivo inhibits the nuclear movement of p53. First, we show that p53.hsp90 heterocomplexes from DLD-1 human colon cancer cells contain an immunophilin (FKBP52, CyP-40, or PP5) as well as dynein. p53.hsp90.immunophilin.dynein complexes can be formed by incubating immunopurified p53 with rabbit reticulocyte lysate, and we show by peptide competition that the immunophilins link via their tetratricopeptide repeat domains to p53-bound hsp90 and by means of their PPIase domains to the dynein complex. The linkage of immunophilins to the dynein motor is indirect by means of the dynamitin component of the dynein-associated dynactin complex, and we show that purified FKBP52 binds directly by means of its PPIase domain to purified dynamitin. By using a temperature-sensitive mutant of p53 where cytoplasmic-nuclear movement occurs by shift to permissive temperature, we show that p53 movement is impeded when p53 binding to hsp90 is inhibited by the hsp90 inhibitor radicicol. Also, nuclear movement of p53 is inhibited when immunophilin binding to dynein is competed for by expression of a PPIase domain fragment in the same manner as when dynein linkage to cargo is dissociated by expression of dynamitin. This is the first demonstration of the linkage between an hsp90-chaperoned transcription factor and the system for its retrograde movement to the nucleus both in vitro and in vivo.Fil: Galigniana, Mario Daniel. University of Michigan; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; ArgentinaFil: Harrell, Jennifer M.. University of Michigan; Estados UnidosFil: O´Hagen, Heather M.. University of Michigan; Estados UnidosFil: Ljungman, Mats. University of Michigan; Estados UnidosFil: Pratt, William B.. University of Michigan; Estados Unido

Enhancing Fund Selection Using Supervised Machine Learning : Evidence From the Nordic Mutual Fund Market

In this research we aim to extend the literature on the performance predictability in actively managed mutual funds. We use the Nordic mutual fund market as our laboratory. We develop a performance-enhancing system to assist retail investors in selecting mutual funds by utilizing gradient boosting, random forest, and deep neural networks. Furthermore, we seek to obtain positive abnormal returns from our predicted quintile portfolios. We thus retrieve data free of survivorship bias for 2748 Nordic mutual funds from Morningstar Direct. First, we run the algorithms to test the possibility of classifying alphas. Secondly, we create a ranking system that categorizes funds based on predicted alpha, enabling us to separate the best from the worst-performing mutual funds. At last, we benchmark our findings against Morningstar’s acknowledged rating platform to examine whether our top quintile portfolios manage to outperform Morningstar’s top quintile portfolio. We find that our models can classify the sign of the alpha coefficient, whereas gradient boosting and random forest does this exceptionally well. Further, we manage to create a categorization system significantly outperforming both an equally weighted and asset weighted benchmark on risk-adjusted returns. Finally, our best performing portfolios generate risk-adjusted returns in excess of Morningstar, although only significantly for gradient boosting. Results are further robust to changes in risk-adjustment models for both equity funds and fixed income funds. The findings are consistent with the current machine learning literature and enable us to state that machine learning algorithms can be used to select successful mutual funds.nhhma