CARGO PREFERENCE LEGISLATION, AGRICULTURAL EXPORTS, AND THE FUTURE OF THE DULUTH-SUPERIOR ECONOMY: A LEGISLATIVE HISTORY AND ECONOMIC ANALYSIS

Community/Rural/Urban Development, International Relations/Trade,

Two-electron temperature model of a laser-driven implosion

The plasma ejected by a pellet irradiated with moderately intense laser light (Icrλ2 ∼1015 W cm−2 μm2, Icr and λ being intensity and wavelength) is analyzed. Both hot electrons caused by resonant absorption, and cold or thermal electrons are considered; no appeal is made to heat‐flux saturation. The cold (hot) population controls the overdense (underdense) plasma flow. Ingoing hot electrons at the critical surface are found to thermalize before reaching the ablation surface. Results obtained are compared with a model that assume one electron temperature, and a saturated flux; agreement requires using a range of saturation factors: 0.1≲f≲0.3. The validity of the model is discussed

Ihh Signaling and Muscle Forces are Required for Enthesis Development

Tendon-to-bone repair is clinically challenging and plagued by high failure rates. The attachment of relatively stiff bone (~20GPa) to more compliant tendon (~200MPa) represents a fundamental engineering challenge. In the native tendon-bone attachment, termed the enthesis, transitional tissue contains gradients of structure and composition that effectively reduce stress concentrations at the boundary between hard and soft tissue. This transitional tissue is replaced by scar after injury and repair, resulting in a mechanically inferior attachment. The goal of this thesis is to study biological and mechanical cues that are critical to the development of the structure and function of the native tendon, which could inspire novel repair strategies to improve tendon-to-bone healing. To accomplish this, we characterized mineralization patterns in the murine supraspinatus enthesis throughout postnatal development on the micro-scale using Raman spectroscopy and at the nano-scale using transmission electron microscopy - electron energy loss spectroscopy. Mineralization of this tissue occured postnatally via endochondral ossification. We observed a constant and approximately linear increase in the mineral-to-collagen ratio at the mineralizing front within the enthesis at all developmental stages. Using a multi-scale linear elastic model of the tendon enthesis, we demonstrated that the mineral gradient amplifies stresses near mineralizing cells early in development while reducing stress concentrations at the mature tendon-bone interface. Next, we investigated tendon enthesis development in the absence of muscle forces. This localized paralysis model resulted in joint level deformities and mineralization defects. We observed a dramatic decrease in the enthesis biomechanical properties accompanied by structural and compositional changes. Collagen fiber alignment was reduced and mineralization defects were observed using Raman spectroscopy and X-ray diffraction. In order to probe the biological mechanisms that might influence development of this tissue, we hypothesized that factors critical to endochondral bone formation will also influence enthesis mineralization. Using a murine reporter of active Indian hedgehog (Ihh) signaling, we identified a population of cells present early in development that populate the mature enthesis. Lineage tracing analyses indicated that this cell population remained at the mature enthesis while down-regulating Ihh signaling in mineralized regions. In the case of reduced muscle forces, Ihh signaling was slightly elevated in this model compared to controls. Eliminating Ihh signaling throughout development using a conditional Smoothened (Smo) knockout mouse model specific to tendon lineage cells resulted in dramatic mineralization defects in the enthesis and reduced biomechanical behavior of the attachment. Taken together, this thesis demonstrates that Ihh signaling and muscle loading are necessary for mineralization and maturation of a mechanically robust tendon-to-bone attachment

Adults with major depression who are suicidal and those who aren't have different cytokines and lipid profiles.

OBJECTIVES: We tested whether Tumor necrosis factor-alpha, Interlukin-1β, and lipid profile might be associated with suicide attempts in adult patients with major depression. DESIGN AND METHODS: Plasma levels of Tumor Necrosis Factor-alpha, Interleukin-1β, and lipid profile were analyzed in 60 adult patients with major depression diagnosed according to DSM-IV criteria for Major depression (22 suicidal attempters and 38 patients without suicidal ideas), and 30 healthy controls. RESULTS: At univariate analyses, plasma level of Tumor Necrosis Factor-alpha and Triglyceride were significantly higher in suicide attempters and non-suicidal attempter depressed patients than those of healthy control (all

The sizzle and fizzle of teacher evaluation in the United States and the selective use of research evidence

In 2009, the United States funded the largest federal educational reform effort in the nation’s history. Referred to as Race to the Top (RTTT), a cornerstone of this effort was the high-stakes evaluation of all teachers, with a significant emphasis on the use of highly researched statistical methods that ascribed changes in student test scores to a teacher’s quality. The widespread endorsement of these policies across a broad range of the political spectrum was based on a theory of action that faced technical, organizational, and political challenges. Enthusiasm for these evaluation efforts was substantially muted in a mere 5 years. Among a number of factors, we argue that the framing of the problem together with privileging particular lines of research and voices, as well as the lack of consideration of other frames and attention to other research and voices, resulted in an evidence base that was wholly insufficient to justify the large-scale policy changes that were enacted

Structure and scaling laws of laser-driven ablative implosions

A stationary, spherical flow model gives the form of laser-driven ablation fronts and scaling laws for the dependence of implosion parameters on laser wavelength, pusher atomic number, and other input quantities. (auth