The effect of pictorial depth information on projected size judgements

When full depth cues are available, size judgements are dominated by physical size. However, with reduced depth cues, size judgements are less influenced by physical size and more influenced by projected size. This study reduces depth cues further than previous size judgement studies, by manipulating monocularly presented pictorial depth cues only. Participants were monocularly presented with two shapes against a background of zero (control), one, two or three pictorial depth cues. Each cue was added progressively in the following order: height in the visual field, linear perspective, and texture gradient. Participants made a „same-different? judgement regarding the projected size of the two shapes, i.e. ignoring any depth cues. As expected, accuracy increased and response times decreased as the ratio between the projected size of the two shapes increased (range of projected size ratios, 1:1 to 1:5). In addition, with the exception of the larger size ratios (1:4 and 1:5), detection of projected size difference was poorer as depth cues were added. One-cue and two-cue conditions had the most weighting in this performance decrement, with little weighting from the three-cue condition. We conclude that even minimal depth information is difficult to inhibit. This indicates that depth perception requires little focussed attention

Characterization of the Mycobacteriophage Ukulele Integration System; Identification of Integration Site Attp and the Role of the Integrase in Lysogeny Regulation

Mycobacteriophage (phage) are a group of viruses that infect bacteria in the genus Mycobacterium. Two phage lifestyles are lytic and temperate. Lytic phage only carry out the lytic life cycle, resulting in host cell lysis. Temperate phage are capable of completing both lytic and lysogenic life cycles. During the lysogenic life cycle, a phage-encoded integrase facilitates integration at sites attP in the phage genome and attB in the host to form a lysogen. The cluster E mycobacteriophage integration system is poorly understood. Ukulele, a lysogenic cluster E phage, is being used to identify the Cluster E attP and characterize lysogeny regulation. A putative attP containing sequence was identified in the Ukulele genome by computational analysis. To confirm the presence of attP, this sequence will be inserted into a plasmid and transferred into integrase expressing M. smegmatis (pST-KT-int). Cells will be screened for plasmid integrated into the genome. To characterize the role of the integrase in lysogeny regulation, we will determine the impact of integrase expression levels on induction event frequency in M. smegmatis (pST-KT-int) – Ukulele lysogens

Exoenzyme Dynamics of Surface Ocean Microbial Communities in Response to Oil Exposure

Oil spills, while one of the most infamous manmade ecological disasters, remain relatively poorly understood, in particular the responses of microbial communities to the diverse suite of components in raw oil and chemical dispersants are just beginning to be elucidated. The 2010 Deepwater Horizon oil spill was historic in not only its volume and ecological damage, but also in the extent to which its progress and effects were monitored, particularly with respect to the microbial community. Analysis of exoenzymes can provide insight into how oil-degrading bacteria, as well as the bacterial community as a whole, respond to the changing chemical conditions experienced over the course of an oil spill. Using a multiscale approach with both mesocosms and three oil-degrading environmental isolates in culture, surface ocean microbes in oiled conditions were shown to be highly active with respect to ẞ-glucosidase, leucine aminopeptidase, and alkaline phosphatase. The activities measured in the mesocosms are some of the highest reported for environmental systems in the literature. Additionally, both coastal and open ocean microbial communities in mesocosms and all three isolates in bottle experiments demonstrated the ability to significantly modify their alkaline phosphatase and ß-glucosidase kinetics over just a few days in culture. Exposure to oil tended to change the patterns in enzyme activity over the course of each experiment. In the mesocosm experiments, differences in enzyme activity between the offshore community and the coastal community were greater than the differences between the control and oil treatments, indicating source microbial community composition has a greater impact than exposure to oil for enzyme activity. Supporting this hypothesis, there was as much variability in activity for alkaline phosphatase and leucine aminopeptidase between the three oil-degrading strains, as between the two mesocosm experiments. In general, the mesocosms had higher Vmax and lower Km values for each enzyme than any of the strains, though for alkaline phosphatase and leucine aminopeptidase the strains showed as much diversity in terms of kinetic values as the mesocosms

Survey of Federal Whistleblower and Anti-Retaliation Laws

This report provides an overview of federal whistleblower and anti-retaliation laws. In general, these laws protect employees who report misconduct by their employers or who engage in various protected activities, such as participating in an investigation or filing a complaint. In recent years, Congress has expanded employee protections for a variety of private-sector workers. Eleven of the forty laws reviewed in this report were enacted after 1999. Among these laws are the Sarbanes-Oxley Act, the FDA Food Safety Modernization Act, and the Dodd-Frank Wall Street Reform and Consumer Protection Act. The report focuses on key aspects of the federal whistleblower and anti-retaliation laws. For each law, the report summarizes the activities that are protected, how the law’s protections are enforced, whether the law provides a private right of action, the remedies prescribed by the law, and the year the law’s whistleblower or anti-retaliation provisions were adopted and amended. With regard to amendment dates, the report identifies only dates associated with substantive amendments. For enactments after 2001, the report provides information on congressional sponsorship and votes

Evaluating the effects of choice across varying levels of preferred items

The current study compared the differential effects of choice and no-choice conditions on skill acquisition, when provided as a consequence and when choice conditions involved the opportunity to choose from an array of items of varying levels of preference (high, moderate, and low preference). These effects were evaluated across four conditions: top preference choice, varying-level preference choice, no choice, and control. Additionally, the current study evaluated children's preferences for choicemaking opportunities among three children with autism spectrum disorder. Results indicated that the top preference choice condition increased treatment efficacy for two of the three participants, and two of the three participants demonstrated preference for choice-making opportunitiesIncludes bibliographical references

Exoenzyme Dynamics of Surface Ocean Microbial Communities in Response to Oil Exposure

Oil spills, while one of the most infamous manmade ecological disasters, remain relatively poorly understood, in particular the responses of microbial communities to the diverse suite of components in raw oil and chemical dispersants are just beginning to be elucidated. The 2010 Deepwater Horizon oil spill was historic in not only its volume and ecological damage, but also in the extent to which its progress and effects were monitored, particularly with respect to the microbial community. Analysis of exoenzymes can provide insight into how oil-degrading bacteria, as well as the bacterial community as a whole, respond to the changing chemical conditions experienced over the course of an oil spill. Using a multiscale approach with both mesocosms and three oil-degrading environmental isolates in culture, surface ocean microbes in oiled conditions were shown to be highly active with respect to ẞ-glucosidase, leucine aminopeptidase, and alkaline phosphatase. The activities measured in the mesocosms are some of the highest reported for environmental systems in the literature. Additionally, both coastal and open ocean microbial communities in mesocosms and all three isolates in bottle experiments demonstrated the ability to significantly modify their alkaline phosphatase and ß-glucosidase kinetics over just a few days in culture. Exposure to oil tended to change the patterns in enzyme activity over the course of each experiment. In the mesocosm experiments, differences in enzyme activity between the offshore community and the coastal community were greater than the differences between the control and oil treatments, indicating source microbial community composition has a greater impact than exposure to oil for enzyme activity. Supporting this hypothesis, there was as much variability in activity for alkaline phosphatase and leucine aminopeptidase between the three oil-degrading strains, as between the two mesocosm experiments. In general, the mesocosms had higher Vmax and lower Km values for each enzyme than any of the strains, though for alkaline phosphatase and leucine aminopeptidase the strains showed as much diversity in terms of kinetic values as the mesocosms

Student Experimental Farm Smart Pathway Lighting System

This project works together with the Student Experimental Farm (SEF) and the DC House in order to install a smart lighting pathway system. This system will run off of DC power supplied by the solar panels connected to the DC House. This project tested and explored the group’s abilities to design and implement a full system run off of 48V DC. By installing this system it will greatly improve the ease for students to work at the SEF beyond daylight hours. The system will allow continuous dull lighting and will switch to full brightness once a person is detected. This feature goes along with the ideals of the DC House, saving energy. This project helped to show the capabilities of a DC system and can impact the lives of those in communities with no access to an AC grid. The results of this system were not as successful as planned. The wiring within the junction boxes proved to be quite tricky so the system does not work at its full potential, however this does lead to further improvements by students to come

Analysis Of Host Factors Involved In Regulating Hiv-1-Induced Syncytium Formation

Human Immunodeficiency Virus type 1 (HIV-1) is a retrovirus and the causative agent of Acquired Immunodeficiency Syndrome (AIDS). HIV-1 can spread through multiple modes of transmission including cell-to-cell transmission between CD4+ T cells at a transient junction known as the virological synapse (VS). The VS forms upon HIV-1 Envelope (Env) on the surface of an infected (producer) cell binding CD4 on an uninfected (target) cell. While the VS typically resolves with complete cell separation and transfer of virus particles, Env can occasionally facilitate cell-cell fusion at this site, forming a multinucleated infected cell (syncytium). Excessive syncytium formation is prevented by viral and host factors, though this subpopulation of infected cells can still comprise ~20% of all infected cells in vivo. T cell-based syncytia detected in vivo are unique from mononucleated infected cells as they contain 2-4 nuclei, can have an elongated morphology, and appear highly motile. Despite such significant presence of syncytia, little is known about how these multinucleated infected entities contribute to HIV-1 spread and pathogenesis. During cell-to-cell transmission at the VS, viral and host factors are enriched at this site to support virus spread (reviewed in Chapter 2). This thesis focused on fusion inhibitory factors HIV-1 Gag and several host proteins, including tetraspanins, ezrin, and EWI-2. We determined that EWI-2 is recruited specifically to the producer cell side of the VS (the presynapse) where it inhibits HIV-1-induced cell-cell fusion in a dose-dependent manner (Chapter 3). Although both EWI-2 and tetraspanins are typically downregulated upon infection, both tetraspanin CD81 and EWI-2 surface levels are partially restored on HIV-1-induced CD4+ primary T cell-based syncytia compared to mononucleated infected cells. We sought to determine whether target cells influence the surface profile upon fusion and whether the altered protein levels are maintained for the lifetime of a syncytium (Chapter 4). We demonstrated that EWI-2 surface levels on syncytia correlate with levels of the target cell population, suggesting that EWI-2 brought along by target cells at least partially restores surface expression in syncytia. Further, we determined that newly formed, “young” syncytia, have higher levels of EWI-2 than older ones, suggesting that downregulation of EWI-2 continues in syncytia. We expect that higher levels of EWI-2 on young syncytia will render them less susceptible to continued cell-cell fusion than mononucleated infected cells and may also reduce virus particle infectivity. This will be tested by analysis of a purified syncytia population to measure fusogenicity and particle infectivity relative to fusogenicity and particle infectivity of mononucleated infected cells. Those data will be included in a future manuscript. Collectively, the work presented in this dissertation has furthered our understanding of HIV-1-induced cell-cell fusion regulation and allowed us to characterize distinct differences in protein expression between syncytia and mononucleated infected cells. These findings open the door to future investigations aimed at understanding how syncytia contribute to virus transmission and pathogenesis

Growth rate and resource imbalance interactively control biomass stoichiometry and elemental quotas of aquatic bacteria

The effects of resource stoichiometry and growth rate on the elemental composition of biomass have been examined in a wide variety of organisms, but the interaction among these effects is often overlooked. To determine how growth rate and resource imbalance affect bacterial carbon (C): nitrogen (N): phosphorus (P) stoichiometry and elemental content, we cultured two strains of aquatic heterotrophic bacteria in chemostats at a range of dilution rates and P supply levels (C:P of 100:1 to 10,000:1). When growing below 50% of their maximum growth rate, P availability and dilution rate had strong interactive effects on biomass C:N:P, elemental quotas, cell size, respiration rate, and growth efficiency. In contrast, at faster growth rates, biomass stoichiometry was strongly homeostatic in both strains (C:N:P of 70:13:1 and 73:14:1) and elemental quotas of C, N, and P were tightly coupled (but not constant). Respiration and cell size increased with both growth rate and P limitation, and P limitation induced C accumulation and excess respiration. These results show that bacterial biomass stoichiometry is relatively constrained when all resources are abundant and growth rates are high, but at low growth rates resource imbalance is relatively more important than growth rate in controlling bacterial biomass composition.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136292/1/ecy1705_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136292/2/ecy1705.pd