The Disestablishment of African American Male Compliant Ambiguity: A Prison Pipeline Essay

There is an apex to each day, a climax, where a decision is made, and a falling action is the result of that decision. Recommendations to combat the never-ending struggle of my invisibility are derived from culturally relevant and culturally responsive frameworks, resiliency frameworks, and ethical caring frameworks. Without systemic reform in local educational settings that includes local teachers, administrators, parents, and students providing new conceptual frameworks for learner and teacher efficacy, the African American male learner will persistently encounter crucial conflicts throughout the School to Prison pipeline while entering a space that has been rendered invisible due to the focus on policy that perpetuates the pipeline. This essay shows that every day when African American boys enter the pipeline, we are faced with two distinct conflicts—Man vs. Man and Man vs. Self—as we navigate an invisible space, compliant ambiguity

Intumescent coating development

A program was completed at the University of Dayton Research Institute in which polyimide and phenolic intumescent coatings were evaluated as supplemental thermal insulation for the sprayed-on foam insulation on the aft bulkhead of the space shuttle external tank. The purpose of the intumescent coating was to provide additional thermal protection during lift-off in order to replace the ablative heat resistant layer with a lighter weight material for increased payload in the shuttle

Predicting the locations of possible long-lived low-mass first stars: Importance of satellite dwarf galaxies

The search for metal-free stars has so far been unsuccessful, proving that if there are surviving stars from the first generation, they are rare, they have been polluted, or we have been looking in the wrong place. To predict the likely location of Population~III (Pop~III) survivors, we semi-analytically model early star formation in progenitors of Milky Way-like galaxies and their environments. We base our model on merger trees from the high-resolution dark matter only simulation suite \textit{Caterpillar}. Radiative and chemical feedback are taken into account self-consistently, based on the spatial distribution of the haloes. Our results are consistent with the non-detection of Pop III survivors in the Milky Way today. We find that possible surviving Population III stars are more common in Milky Way satellites than in the main Galaxy. In particular, low mass Milky Way satellites contain a much larger fraction of Pop~III stars than the Milky Way. Such nearby, low mass Milky Way satellites are promising targets for future attempts to find Pop~III survivors, especially for high-resolution, high signal-to-noise spectroscopic observations. We provide the probabilities for finding a Pop~III survivor in the red giant branch phase for all known Milky Way satellites to guide future observations.Comment: 17 pages, 12 figures, 1 table, submitted to MNRA

Metalloproteinase expression in venous aneurysms

IntroductionAlthough recognized with increasing frequency, the pathogenesis of venous aneurysms (VA) remains poorly understood. We evaluated 8 patients with 10 VA for the presence, localization and activity of metalloproteinases (MMPs).MethodsTissue specimens from VA (n=8), normal saphenous vein (NSV n=7) and varicose veins (VV n=7 were compared by histology and immunohistochemistry (IHC). Histologic sections were stained with H&E, Movats pentachrome and toluidine blue, and IHC specimens with antibodies to CD68, MMP2, MMP9, and MMP13. Protein expression and enzyme activity were determined by Western immunoblotting and zymography.ResultsThree of 4 patients with popliteal VA presented with edema and leg pain and the remaining patient with deep venous thrombosis (DVT) and pulmonary embolism (PE). The 5 popliteal VA were treated by; excision and reanastomosis (n=2) lateral venorrhaphy (n=2) and spiral saphenous vein graft (n=1). The 3 patients with 4 upper extremity VA had discomfort over a compressible mass. Two of the VA were excised and the remaining patients aneurysm ruptured spontaneously. The mesenteric VA, an incidental finding at laparotomy was excised. Thrombus was present in 2 popliteal, 1 upper extremity and in the mesenteric aneurysm. Histologically, VA and VV were characterized by fragmentation of the elastic lamellae, loss of smooth muscle cells (SMCs) and attenuation of the venous wall when compared to NSV. Varicose veins and VA also demonstrated increased expression of MMP-2, MMP-9 and MMP-13 in endothelial cells (ECs), SMCs and adventitial microvessels compared to NSV. Both pro-MMP-2 and pro-MMP-9 were detected by zymography in VA,VV and NSV but only MMP-2 activity was demonstrable.ConclusionsThe structural changes in the venous wall in addition to the increased expression of MMP-2, MMP-9 and MMP-13 in VA compared to NSV and VV suggests a possible causal role for these MMPs in their pathogenesis

Descendants of the first stars: the distinct chemical signature of second generation stars

Extremely metal-poor (EMP) stars in the Milky Way (MW) allow us to infer the properties of their progenitors by comparing their chemical composition to the metal yields of the first supernovae. This method is most powerful when applied to mono-enriched stars, i.e. stars that formed from gas that was enriched by only one previous supernova. We present a novel diagnostic to identify this subclass of EMP stars. We model the first generations of star formation semi-analytically, based on dark matter halo merger trees that yield MW-like halos at the present day. Radiative and chemical feedback are included self-consistently and we trace all elements up to zinc. Mono-enriched stars account for only $\sim 1\%$ of second generation stars in our fiducial model and we provide an analytical formula for this probability. We also present a novel analytical diagnostic to identify mono-enriched stars, based on the metal yields of the first supernovae. This new diagnostic allows us to derive our main results independently from the specific assumptions made regarding Pop III star formation, and we apply it to a set of observed EMP stars to demonstrate its strengths and limitations. Our results may provide selection criteria for current and future surveys and therefore contribute to a deeper understanding of EMP stars and their progenitors.Comment: 18 pages, 20 figures, published in MNRA

Direction of Arrival and the Rank-Revealing URV Decomposition

In many practical direction-of-arrival (DOA) problems the number of sources and their directions from an antenna array do not remain stationary. Hence a practical DOA algorithm must be able to track changes with a minimal number of snapshots. In this paper we describe DOA algorithms, based on a new decomposition, that are not expensive to compute or difficult to update. The algorithms are compared with algorithms based on the singular value decomposition (SVD). (Also cross-referenced as UMIACS-TR-91-166

Globular cluster formation within the Aquarius simulation

The Aquarius project is a very high-resolution simulation capable of resolving the full mass range of potential globular cluster (GC) formation sites. With a particle mass mp= 1.4 × 104 M¿, Aquarius yields more than 100 million particles within the virial radius of the central halo which has a mass of 1.8 × 1012 M¿, similar to that of the Milky Way. With this particle mass, dark matter concentrations (haloes) that give rise to GCs via our formation criteria contain a minimum of ~2000 particles. Here, we use this simulation to test a model of metal-poor GC formation based on collapse physics. In our model, GCs form when the virial temperatures of haloes first exceed 104 K as this is when electronic transitions allow the gas to cool efficiently. We calculate the ionizing flux from the stars in these first clusters and stop the formation of new clusters when all the baryonic gas of the Galaxy is ionized. This is achieved by adopting reasonable values for the star formation efficiencies and escape fraction of ionizing photons which result in similar numbers and masses of clusters to those found in the Milky Way. The model is successful in that it predicts ages (peak age ~13.3 Gyr) and a spatial distribution of metal-poor GCs which are consistent with the observed populations in the Milky Way. The model also predicts that less than 5 per cent of GCs within a radius of 100 kpc have a surviving dark matter halo, but the more distant clusters are all found in dark matter concentrations. We then test a scenario of metal-rich cluster formation by examining mergers that trigger star formation within central gas discs. This results in younger (~7¿13.3 Gyr), more centrally located clusters (40 metal-rich GCs within 18 kpc from the centre of the host) which are consistent with the Galactic metal-rich population. We test an alternate model in which metal-rich GCs form in dwarf galaxies that become stripped as they merge with the main halo. This process is inconsistent with observed metal-rich globulars in the Milky Way because it predicts spatial distributions that are far too extended

Chronic Administration of the Glucagon-Like Peptide-1 Analog, Liraglutide, Delays the Onset of Diabetes and Lowers Triglycerides in UCD-T2DM Rats

ObjectiveThe efficacy of liraglutide, a human glucagon-like peptide-1 (GLP-1) analog, to prevent or delay diabetes in UCD-T2DM rats, a model of polygenic obese type 2 diabetes, was investigated.Research design and methodsAt 2 months of age, male rats were divided into three groups: control, food-restricted, and liraglutide. Animals received liraglutide (0.2 mg/kg s.c.) or vehicle injections twice daily. Restricted rats were food restricted to equalize body weights to liraglutide-treated rats. Half of the animals were followed until diabetes onset, whereas the other half of the animals were killed at 6.5 months of age for tissue collection.ResultsBefore diabetes onset energy intake, body weight, adiposity, and liver triglyceride content were higher in control animals compared with restricted and liraglutide-treated rats. Energy-restricted animals had lower food intake than liraglutide-treated animals to maintain the same body weights, suggesting that liraglutide increases energy expenditure. Liraglutide treatment delayed diabetes onset by 4.1 ± 0.8 months compared with control (P < 0.0001) and by 1.3 ± 0.8 months compared with restricted animals (P < 0.05). Up to 6 months of age, energy restriction and liraglutide treatment lowered fasting plasma glucose and A1C concentrations compared with control animals. In contrast, liraglutide-treated animals exhibited lower fasting plasma insulin, glucagon, and triglycerides compared with both control and restricted animals. Furthermore, energy-restricted and liraglutide-treated animals exhibited more normal islet morphology.ConclusionsLiraglutide treatment delays the development of diabetes in UCD-T2DM rats by reducing energy intake and body weight, and by improving insulin sensitivity, improving lipid profiles, and maintaining islet morphology