Food chain

A descriptive narration of a project to create a 3-D computer animated film, Food Chain, about a greedy man who lives on an island. He enslaves a bird to catch fish for him, but he catches more than he bargained for. Includes original proposal and revised story, original and revised storyboards, and color stills

Phylogenetic Analysis of Algal Symbionts Associated with Four North American Amphibian Egg Masses

Egg masses of the yellow-spotted salamander Ambystoma maculatum form an association with the green alga “Oophila amblystomatis” (Lambert ex Wille), which, in addition to growing within individual egg capsules, has recently been reported to invade embryonic tissues and cells. The binomial O. amblystomatis refers to the algae that occur in A. maculatum egg capsules, but it is unknown whether this population of symbionts constitutes one or several different algal taxa. Moreover, it is unknown whether egg masses across the geographic range of A. maculatum, or other amphibians, associate with one or multiple algal taxa. To address these questions, we conducted a phylogeographic study of algae sampled from egg capsules of A. maculatum, its allopatric congener A. gracile, and two frogs: Lithobates sylvatica and L. aurora. All of these North American amphibians form associations with algae in their egg capsules. We sampled algae from egg capsules of these four amphibians from localities across North America, established representative algal cultures, and amplified and sequenced a region of 18S rDNA for phylogenetic analysis. Our combined analysis shows that symbiotic algae found in egg masses of four North American amphibians are closely related to each other, and form a well-supported clade that also contains three strains of free-living chlamydomonads. We designate this group as the ‘Oophila’ clade, within which the symbiotic algae are further divided into four distinct subclades. Phylogenies of the host amphibians and their algal symbionts are only partially congruent, suggesting that host-switching and co-speciation both play roles in their associations. We also established conditions for isolating and rearing algal symbionts from amphibian egg capsules, which should facilitate further study of these egg mass specialist algae

Essays on Business Networks in the Multi-level Marketing Industry

This dissertation contributes to our knowledge of how social factors (e.g., homophily, the existence of others) influence individual business behaviors. To explore the influence of social factors, the Multi-level Marketing (MLM) Industry is especially suitable because social and business networks are interrelated. MLM is a major type of direct selling wherein Independent Business Owners (IBOs) recruit others, who become IBOs themselves. IBOs in MLM are pivotal because they both serve end-customers and expand and maintain the IBO network. However, as these IBOs are not firm employees, understanding the relationships among them is critical. Two important questions are addressed. How is the IBO network created (Essay One)? How do IBOs influence the activity of other IBOs (Essay Two)? Essay One, "Social versus Economic Factors in Business Network Formation: An Empirical Analysis of the Multi-level Marketing Industry," explores how IBOs form networks between IBOs and new joiners. Unlike social networks, where relationships are mainly driven by social motives, IBOs and new joiners in MLM also expect economic returns. Thus, I investigate network formation in terms of social and economic factors. Moreover, I investigate how the relationship value between the IBO and the new joiner affects the new joiner's future business activities. By employing a structural Bayesian two-sided matching model, I find that both factors significantly affect network formation. However, economic factors are more important than social factors, playing a significant role in determining the network relationship. Also, social factors are significant in forming the network relationship but are less influential driving new joiners to engage in business activities in the future. Finally, new joiners who are driven primarily by economic factors at the formation stage show significantly more business activity. Essay Two, "The Impact of Existence of Others on Inactive Behavior in the Multi-level Marketing Industry," examines one specific aspect of IBOs' turnover behavior. There is a vast literature on turnover, yet its main focus is on traditional hierarchical organizations. MLM has a unique industry environment, which suggests that previous findings may not apply. Specifically, relationships among IBOs are highly emphasized; they are often seen as personal, yet competition among IBOs remains despite the importance of coordinating efforts. Given these unique features, I focus on how IBOs' inactivity can be quantitatively understood in relation to three different dimensions of others (Individual, Network family, and Proximity). One focal aspect is status, which is awarded by MLM firms to successful IBOs to motivate IBOs. Analyzing county-level and individual-level data, I find consistent evidence that being near high status IBOs decreases inactivity --- a protective effect. The results hold true at the network family level and for proximity. Also, IBOs with a larger family tended to stay active. However, having more IBOs in proximity increased inactivity, indicating that competition in proximity seems inevitable. Lastly, neural network is applied to predict inactivity, which reveals a similar conclusion about the role of high status IBOs. These findings have implications for the MLM industry, which has an interest in maintaining the IBO sales force.PHDBusiness AdministrationUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/138716/1/eunsoo_1.pd

The State of Essential Newborn Care for Skilled Home Deliveries and Facility Deliveries in Bangladesh

Background: Essential newborn care (ENC) around the time of birth is critical in improving neonatal survival. This study assessed the coverage of ENC performed at or immediately after birth and examined the odds of newborns receiving ENC based on the mothers' place of delivery and assistance during delivery in Bangladesh. Methods: Weighted descriptive statistics and logistic regressions were performed on ENC practices from the 2011 Bangladesh Demographic and Health Survey dataset. ENC practices included: non-application of substances to the cord; application of antiseptic to the cord; drying newborn within 5 minutes; wrapping newborn within 5 minutes; delaying first bath until after the first 72 hours; and breastfeeding within 1 hour. The key predictor variables included unskilled home delivery, skilled home delivery and facility delivery. Results: Coverage for ENC practices was generally low. Compared to unskilled home delivery, delivery at sub-district level health facilities and secondary/tertiary health facilities showed significantly higher odds for all ENC practices except non-application of substances to the cord and breastfeeding within 1 hour. The odds ratios between unskilled home delivery and skilled home delivery as well as delivery at lower level health facilities were not statistically significant for many ENC practices. Conclusions : These findings have significant public health implications as lower level health facilities are typically the first point of entry into the healthcare system. The coverage of ENC should be closely monitored for skilled delivery at home and particularly, for delivery at lower level health facilities in Bangladesh.Master of Science in Public Healt

Co-Cultures of Oophila Amblystomatis Between Ambystoma Maculatum and Ambystoma Gracile Hosts Show Host-Symbiont Fidelity

A unique symbiosis occurs between embryos of the spotted salamander (Ambystoma maculatum) and a green alga (Oophila amblystomatis). Unlike most vertebrate host-symbiont relationships, which are ectosymbiotic, A. maculatum exhibits both an ecto- and an endo-symbiosis, where some of the green algal cells living inside egg capsules enter embryonic tissues as well as individual salamander cells. Past research has consistently categorized this symbiosis as a mutualism, making this the first example of a “beneficial” microbe entering vertebrate cells. Another closely related species of salamander, Ambystoma gracile, also harbors beneficial Oophila algae in its egg capsules. However, our sampling within the A. gracile range consistently shows this to be a strict ectosymbiotic interaction—with no sign of tissue or presumably cellular entry. In this study we swapped cultured algae derived from intracapsular fluid of different salamander hosts to test the fidelity of tissue entry in these symbioses. Both A. maculatum and A. gracile embryos were raised in cultures with their own algae or algae cultured from the other host. Under these in vitro culture conditions A. maculatum algae will enter embryonic A. maculatum tissues. Additionally, although at a much lower frequency, A. gracile derived algae will also enter A. maculatum host tissues. However, neither Oophila strain enters A. gracile hosts in these co-culture conditions. These data reveal a potential host-symbiont fidelity that allows the unique endosymbiosis to occur in A. maculatum, but not in A. gracile. However, preliminary trials in our study found that persistent endogenous A. maculatum algae, as opposed to the cultured algae used in subsequent trials, enters host tissues at a higher frequency. An analysis of previously published Oophila transcriptomes revealed dramatic differences in gene expression between cultured and intracapsular Oophila. These include a suite of genes in protein and cell wall synthesis, photosynthesis, central carbon metabolism suggesting the intracapsular algae are assimilating ammonia for nitrogen metabolism and may be undergoing a life-cycle transition. Further refinements of these co-culture conditions could help determine physiological differences between cultured and endogenous algae, as well as rate-limiting cues provided for the alga by the salamander

Transciptome Analysis Illuminates the Nature of the Intracellular Interaction in a Vertebrate-Algal Symbiosis

During embryonic development, cells of the green alga Oophila amblystomatis enter cells of the salamander Ambystoma maculatum forming an endosymbiosis. Here, using de novo dual-RNA seq, we compared the host salamander cells that harbored intracellular algae to those without algae and the algae inside the animal cells to those in the egg capsule. This two-by-two-way analysis revealed that intracellular algae exhibit hallmarks of cellular stress and undergo a striking metabolic shift from oxidative metabolism to fermentation. Culturing experiments with the alga showed that host glutamine may be utilized by the algal endosymbiont as a primary nitrogen source. Transcriptional changes in salamander cells suggest an innate immune response to the alga, with potential attenuation of NF-κB, and metabolic alterations indicative of modulation of insulin sensitivity. In stark contrast to its algal endosymbiont, the salamander cells did not exhibit major stress responses, suggesting that the host cell experience is neutral or beneficial

The Role of Health Facilities in Women’s Use of Maternal and Newborn Postnatal Care in Malawi

The postnatal period is a vulnerable time for both the mothers and the newborns. Receiving timely and quality postnatal care during this period can be important for their survival. The objective of this dissertation was to examine how health facilities play a role in women’s use of maternal and newborn postnatal care in Malawi. In the first paper, it was found that the majority of rural Malawian women lived within 10 km of a health facility that provided postnatal care services. Having a clinic-level facility providing postnatal care services was not found to be significantly associated with maternal and newborn postnatal care in most cases. Because clinic-level facilities and health centers should be at the forefront of providing primary healthcare services, these facilities should all be supported to provide quality preventative postnatal care services. In addition, raising community awareness about the importance of timely postnatal care would be important. In the second paper, it was found that less than half of women who deliver in facilities received maternal postnatal check before facility discharge. A little over two-thirds received newborn postnatal check before discharge. Considering that most women deliver in government-operated hospitals or health centers in Malawi, these facilities should be targeted for intervention. Compared to delivering in government hospitals, delivering in private hospitals had higher effects on maternal and newborn postnatal care before discharge. Receipt of cesarean section had higher effects as well. It is important for health facilities to revisit their protocols for providing postnatal care. Task-shifting to lower-level health workers may also be necessary. The objective is to have all women and newborns delivering at the facilities receive postnatal care before they are discharged. In conclusion, there is much work to be done until all delivering women and their newborns benefit from timely and quality postnatal care services, regardless of their place of delivery. This dissertation contributes to the existing literature by offering important insights about the current state of postnatal care provision in Malawi and bringing more understanding about the role of health facilities in postnatal care use.Doctor of Philosoph