Morphometric analysis of ears in two families of pinnipeds

Submitted in partial fulfillment of the requirements for the degree of Master of Science at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution August 2001Pinniped (seal and sea lion) auditory systems operate in two acoustically distinct environments, air and water. Piniped species differ in how much time they typically spend in water. They therefore offer an exceptional opportunity to investigate aquatic versus terrestrial hearing mechanisms. The Otariidae (sea lions and fur seals) generally divide their time evenly between land and water and have several adaptations; e.g. external pinnae, related to this lifestyle. Phocidae (true seals) spend the majority of their time in water; they lack external pinnae and have well developed ear canal valves. Differences in hearing ranges and sensitivities have been reported recently for members of both of these familes (Kastak, D., Schusterman, RJ., 1998. Low frequency amphibious hearing in pinnipeds. J. Acoust. Soc. Am. 1303,2216- 2228.; Moore, P.W.B., Schusterman, RJ., 1987. Audiometric assessment of northern fur seals, Callorhinus ursinus. Mar. Mamm. Sci. 3,31-53.). In this project, the ear anatomy of three species of pinnipeds: an otariid, the California sea lion (Zalophus californianus), and two phocids, the northern elephant seal (Mirounga angustirostris) and the harbor seal (Phoca vitulina), was examined using computerized tomography (CT scans) and gross dissection. Thee-dimensional reconstructions of the heads and ears from CT data were used to determine interaural dimensions and ossicular chain morphometrics. Ossicular weights and densities were measured conventionally. Results strongly support a canalcentric system for pinniped sound reception and localization. Further, true seals show adaptations for aquatic high frequency specialization.I was supported by an NDSEG fellowship from ONR

New amine-substituted cyclopentadienyl and indenyl ligands

This thesis concerns the new amine-substituted cyclopentadiene and indene ligands C(_5)H(_5)(CH(_2))(_3)N((^t)Bu)H and C(_9)H(_7)(CH(_2))(_3)N((^t)Bu)H which can co-ordinate to a metal through all five carbon atoms of the five-membered ring (η(^5)) and/ or through the nitrogen (σ). Chapter 1 reviews the recent literature concerning Lewis-base functionalised cyclopentadienyl and indenyl ligands and their compounds with s-, p-, d- and f-block metals. Chapter 2 contains a brief review of possible synthetic routes to amine-substituted cyclopentadienyl and indenyl ligands with some examples from the recent literature, and a detailed account of the synthesis of C(_5)H(_5)(CH(_2))(_3)N((^t)Bu)H and C(_9)H(_7)(CH(_2))(_3)N((^t)Bu)H. The amino alcohol (^t)BuNH(CH(_2))(_3) OH was synthesised by the conjugate addition of (^t)BuNH(_2) to ethyl acrylate and reduction of the product ester (^t)BuNH(CH(_2))(_2)C0(_2)Et using LiAIH(_4). (^t)BuNH(CH(_2))(_3)OH was converted into (^t)BuNH(CH(_2))(_3)Br.HBr and (^t)BuNH(CH(_2)(_3)Cl.HCl by reaction with HBr or SOCI(_2). Reaction between (^t)BuNH(CH(_2))(_3)C1.HC1 and two equivalents of Na(C(_5)H(_5)) gave C(_5)H(_5)(CH(_2))(_3)N((^t)Bu)H in good yield. Treatment of (^1)BuNH(CH(_2))(_3)C1.HC1 with excess NaOH followed by reaction with Li(C(_9)H(_7)) gave C(_9)H(_7)(CH(_2))(_3)N((^t)Bu)H, also in good yield. Chapter 3 describes the synthesis of various main group and iron compounds of C(_5)H(_5)(CH(_2))(_3)N((^t)Bu)H and C(_9)H(_7)(CH(_2))(_3)N((^t)Bu)H. Lithium salts Li[C(_5)H(_4)(CH(_2))(_3)N((^t)Bu)H], Li[C(_5)H(_4)(CH(_2))(_3)N((^t)Bu)]Li, Li[C(_9)H(_6)(CH(_2))(_3)N((^t)Bu)H] and Li[C(_9)H(_6)(CH(_2))(_3)N((^t)Bu)]Li were prepared for use as reactive intermediates and Li[C(_5)H(_4)(CH(_2))(_3)N((^t)Bu)H] was characterised as its THF-adduct by (^t)H NMR spectroscopy. The silyl derivatives (Me(_3)Si)C(_5)H(_4)(CH(_2))(_3)NH(^t)Bu and (Me(_3)Si)C(_5)H(_4)(CH(_2))(_3)N((^t)Bu)SiMe(_3) were synthesised and characterised by NMR spectroscopy, and (Me(_3)Si)C(_9)H(_6)(CH(_6))(_3)N((^t)Bu)H and (Me(_3)Si)C(_9)H(_6)(CH(_2))(_3)N((^t)Bu)(SiMe(_3)) were also synthesised. The anune-substituted ferrocene Fe{η(^5)-C(_5)H(_4)(CH(_2))(_3)N((^t)Bu)H}(_2) was synthesised and oxidised to the corresponding ferricenium ion which was isolated as its PF(_6)(^-) salt. Exploratory work was carried out into the preparation of heterobimetallic species by reaction between Fe{η(^5)-C(_5)H(_4)(CH(_2))(_3)N((^t)Bu)H}(_2) and MX(_2) (M = Co, Ni, X = CI, M = Mn, X = Br). The substituted bis(indenyl) iron(II) complex Fe{η(^5)-C(_9)H(_6)(CH(_2))(_3)N((^t)Bu)H}(_2) was also synthesised. Chapter 4 is an account of the chemistry of {η(^5) :σ-C(_5)H(_4) (CH(_2))(_3)N(^t)Bu}Ti(NMe(-2))(_2) which was synthesised by an aminolysis reaction between C(_5)H(_5)(CH(_2))(_3)NH(^t)Bu and Ti(NMe(_2))(_4) Reaction between this compound and various weak acids gave a range of new compounds including{η(^5):σ-C(_5)H(_4)(CH(_2))(-3)N(^t)Bu} Ti(O(^t)Pr)(_2), {η(^5):σ-C(_5)H(_4)(CH(_2))(_3)N(^t)Bu)(_2), {η(^5):σC, {η(^5):σ-C(_5)H(_4)(CH(_2))(_3)N(^t)Bu}Ti(C(_5)H(_5))(NMe(_2)) , {η(^5):σ-C(_5)H(_4)(CH(_2))(_3)N(^t)Bu}Ti(SnBu(_3))(_z) and the imido-bridged dimer [{η(^5):σ-C(_5)H(_4)(CH(_2))(_3)N(^t)Bu}Ti(NHPh)](_2)(µ-NPh)2, the X-ray structure of which is reported. Chapter 5 describes the experimental procedures used, and chapter 6 gives lists of characterising data for each compound. Appendix A gives details of the methods used for magnetic susceptibility determinations; appendix B lists X-ray crystallographic data for [ {η(^5):σ-C(_5)H(_4)(CH(_2))(_3)N(^t)Bu}Ti(NHPh)](_2)(µ-NPh)(_2) and appendix C lists departmental colloquia attended

Growth Mindset As an Approach for Improving Our Lives and Our Students\u27 Lives (August 2017)

This interactive presentation expands on the concept of growth mindset, the concept that growth and learning can come from failure, and discusses the impact that adopting a growth mindset can have on ourselves and our students. Concludes with some concrete suggestions for cultivating a growth mindset and embracing the power of yet

It's time for Canadian community early warning systems for illicit drug overdoses

Although fatal and non-fatal overdoses represent a significant source of morbidity and mortality, current systems of surveillance and communication in Canada provide inadequate measurement of drug trends and lack a timely response to drug-related hazards. In order for an effective early warning system for illicit drug overdoses to become a reality, a number of elements will be required: real-time epidemiologic surveillance systems for illicit drug trends and overdoses, inter-agency networks for gathering data and disseminating alerts, and mechanisms for effectively and respectfully engaging with members of drug using communities. An overdose warning system in an urban area like Vancouver would ideally be imbedded within a system that monitors drug trends and overdoses by incorporating qualitative and quantitative information obtained from multiple sources. Valuable information may be collected and disseminated through community organizations and services associated with public health, emergency health services, law enforcement, medical laboratories, emergency departments, community-based organizations, research institutions and people with addiction themselves. The present paper outlines considerations and conceptual elements required to guide implementation of such systems in Canadian cities such as Vancouver

Motivations to deposit:two approaches to Open Educational Resources (OER) within Languages and Social Sciences (LSS) at Aston University

In Spring 2009, the School of Languages and Social Sciences (LSS) at Aston University responded to a JISC (Joint Information Systems Committee) and Higher Education Academy (HEA) call for partners in Open Educational Resources (OER) projects. This led to participation in not one, but two different OER projects from within one small School of the University. This paper will share, from this unusual position, the experience of our English tutors, who participated in the HumBox Project, led by Languages, Linguistics and Area Studies (LLAS) and will compare the approach taken with the Sociology partnership in the C-SAP OER Project , led by the Centre for Sociology, Anthropology and Politics (C-SAP). These two HEA Subject Centre-led projects have taken different approaches to the challenges of encouraging tutors to deposit teaching resources, as on ongoing process, for others to openly access, download and re-purpose. As the projects draw to a close, findings will be discussed, in relation to the JISC OER call, with an emphasis on examining the language and discourses from the two collaborations to see where there are shared issues and outcomes, or different subject specific concerns to consider

The Regency novel and the British constitution: Austen, Brunton, Shelley, and the culture of Romantic decline

During the Regency period (1811-1820), Britons were faced at home with daunting political problems: a scandal-plagued royal family; ongoing war with France; a weak postwar economy; a complicated and relatively new union of Scotland with England and Wales; and an enormous new empire abroad that few understood and none knew how to manage. As a hedge against this apparent national decline, Britons made frequent recourse to an ideal of national cohesion they called the British constitution: in medicine, the constitution (or health) of British bodies; in domestic matters, the constitution of the British family; in science, the constitution of the British atmosphere and landscape; in politics, the constitution of the British polity out of the English, the Welsh, and the Scottish; in government, the constitutional monarchy comprising the House of Lords, the House of Commons, and the king; in jurisprudence, the body of parliamentary law known as the British Constitution. Constitution was for Britons a multivalent and extremely powerful term that emphasized the interrelatedness of political, legal, social, environmental, and medical understandings of lived experience. And yet, as the nineteenth century moved into its second decade, Britons were nevertheless convinced that theirs was a national constitution on the verge of ruin. This dissertation assesses the interaction of British constitutions--physiological, legal, and national--with genre in the Regency-era novels of Jane Austen, Mary Brunton, and Mary Shelley. These novels are no exception to the larger trend of Regency-era declinism; what makes these women's fictive appraisals of Britain's ruin so remarkable is how they use gender and genre categories to unsettle the seemingly stable idea of a British constitution. The novel was primed for this political work because it was the principal conduit through which Britons indulged their obsession with constitutional decline: eighteenth-century sentimental and gothic fictions almost universally feature as a plotline the constitutional ruin of heroines. In their Regency-era novels, Austen, Brunton, and Shelley seized upon this older tradition to level its sexual double standard: constitutional decline, they insist, inheres not in women's bodies (as the sentimental and gothic traditions held), but in a social order--and a literary tradition--that maintained women and other disenfranchised groups in positions of precarious constitutional legitimacy. Taken together, the Regency-era novels of Austen, Brunton, and Shelley demonstrate that the British constitution--that old ideal of national cohesion--might be nothing more (and certainly nothing less) than Britain's greatest national fiction.Doctor of Philosoph

The Role of Non-Classical Monocytes and the CX3CL1/CX3CR1 Axis in the Immune Response to Myocardial Ischemia-Reperfusion

PhD ThesisMyocardial Infarction is a leading cause of morbidity and mortality worldwide. Over the past decade, STEMI patient prognosis has improved in line with the increased clinical use of reperfusion therapy by primary percutaneous coronary intervention. Despite advances in treatment however, the mortality rate following STEMI remains up to 43.1%, due to a range of short and long term complications. Novel treatment options are therefore required to improve outcome following MI. In the immune response to MI, monocytes are rapidly recruited to the injured tissue where they contribute to the inflammatory milieu. While the function of classical monocytes in this response has been well described, the role of the non-classical monocyte subset is poorly defined. These cells express high levels of the fractalkine receptor, CX3CR1, which has increasingly been implicated in cardiac ischemia-reperfusion (I/R) injury. Expression of the fractalkine ligand, CX3CL1, also known as Fractalkine (FKN) is elevated in mouse models of MI, and neutralization of the ligand leads to improved survival. Similarly, in MI and heart failure patients, plasma levels of the soluble form of CX3CL1 are increased. The aim of this project was therefore to investigate non-classical monocyte behaviour and function following cardiac I/R, with relation to CX3CR1 expression, in both STEMI patients and a mouse model of cardiac I/R. The research presented in this thesis describes the distinct dynamics of CX3CR1hi non-classical monocytes in STEMI patients immediately following reperfusion. These cells show an increased depletion in patients with larger infarcts and lower left ventricular ejection fraction, thereby acting as a potential prognostic biomarker of myocardial outcome. In complementary pre-clinical mouse studies of cardiac I/R, this project established that monocyte adherence in the coronary vessel endothelium occurs over a post-reperfusion timeframe which corresponds approximately to the 90 min post-reperfusion drop in circulating non-classical monocytes in STEMI patients. Investigation of CX3CR1 function using a Cx3cr1 knockout mouse demonstrated that infarct-triggered monocyte recruitment and later decrease in myocardial function are not significantly affected by loss of the Cx3cr1 gene. Research into the signalling pathways downstream of CX3CR1 activation identified the pro-inflammatory NFkB pathway as a possible contributor to non-classical monocyte function. Based on this study, the CX3CL1/CX3CR1 axis appears to have an important role in mediating the acute post-reperfusion dynamics and function of circulating non-classical monocytes following human cardiac I/R. Unexpectedly, however, loss of Cx3cr1 in pre-clinical mouse models does not appear to compromise intra-myocardial monocyte recruitment or heart function following cardiac I/R

An Exploration of the Transition to Graduate School in Mathematics

This purpose of this research was to explore the transition to graduate school in mathematics--the struggles students face, the expectations they must meet, and the strategies they use to deal with this new chapter in their academic experience. In this qualitative study, interview data regarding this transition--collected from 13 mathematics graduate students and eight mathematics faculty members on one university campus--is presented. Based on transcriptions of digital audio recordings of the interviews, interview data were thematically coded and analyzed to yield the themes below.Within the student interview data, four main themes emerged: Isolation vs. Community, Academic Relationships, Role of the Department, and Realizations of Self. First, all student participants mentioned the importance of the academic and social community of their fellow graduate students to their ultimate success in graduate school. Next, students also discussed the impacts of their relationships with new, more difficult mathematical content and with their (instructing) professors in their overall transition experiences. Beyond these relationships, students noted that their transitions were impacted by the department's policies and the availability of information. Lastly, many participants commented on their perspective changes or personal growth through the graduate school experience.From the faculty data, four themes also emerged: Nature of Mathematics, Preparation, Community, and Professional "Place." First, faculty participants noted the difficulty inherent in obtaining a graduate degree in mathematics, as well as insights into the professional mathematical culture. Next, faculty discussed their views on students' academic and psychological preparation (or under-preparation) for graduate work. Faculty participants also emphasized the importance of both academic and social community in making the transition to graduate school as smooth as possible for new students. Finally, faculty members observed that graduate students must be prepared to take on a professional role in mathematics, finding a balance between mathematics and personal life.Based on these data, although some themes seem to be universal to the transition to graduate school in mathematics (such as the importance of community), others can be viewed quite differently by graduate students and departmental faculty (such as students' levels of academic and psychological preparation)

The mechanism by which potassium causes neurite retraction in lamprey descending neurons in cell culture

Abstract only availableSevere spinal cord injury (SCI) disrupts descending axons from reticulospinal (RS) neurons that project to the spinal cord. In most “higher” vertebrates, including humans, recovery is very minimal due to limited regeneration in the central nervous system, and paralysis is usually permanent below the injury site. In several lower vertebrates, including the lamprey, behavioral recovery is almost complete following SCI due to robust axonal regeneration. To study the cellular and molecular mechanisms that regulate axonal regeneration, neurons are often isolated in cell culture so that the factors that influence neurite outgrowth can be studied under controlled conditions. In our laboratory, we have developed a cell culture system in which neurite outgrowth of RS neurons can be studied (Hong et al., 2002; Ryan et al., 2004). Application of glutamate, an excitatory neurotransmitter, to the growth cones of RS neurons results in neurite retraction, presumably because of depolarization, calcium influx, and an increase in intracellular calcium. Intracellular calcium is thought to be one of the important regulators of the rate and direction of neurite outgrowth. Calcium influx could result from at least two different channels: chemically-gated channels (e.g. NMDA channels); or voltage-gated calcium channels. The purpose of the present study was to determine if calcium influx via voltage-gated calcium channels is sufficient to elicit neurite retraction. First, focal application of a 31 M potassium to growth cones of DiI-labeled RS neurons in culture to open voltage-gated calcium channels significantly reduced neurite growth rates, including neurite retraction, compared to pre-control periods. Second, 2 of Co++ or 300 M Cd++, which block calcium channels, abolished potassium-induced neurite retraction. In conclusion, the results suggest that calcium influx via voltage-gated calcium channels is sufficient to cause neurite retraction. Other experiments will determine if influx through voltage-gated channels is necessary for glutamate to elicit neurite outgrowth. Determination of the factors that regulate neurite outgrowth may provide information about the mechanism by which RS neurons regenerate their axons following spinal cord injury and restore locomotor function.Life Sciences Undergraduate Research Opportunity Progra