Serious with the Wordplay: Battle Rap as a Critical Literacy Site and Model

Critical scholars contend it must be the duty of those who are marginalized to create pedagogy that will empower themselves. As such, researchers continue to explore ways and means by which Black male students can engage with and enact literacy. While a significant amount of research has been conducted on hip-hop pedagogies and literacy, there lacks examination into how the specific element of battle rap functions as a location to cultivate the critical consciousness of students. This research seeks to highlight how the genre of battle rap can be a pedagogical tool of literary expression, while simultaneously shedding traditional standards of instruction which have constrained learning opportunities, particularly for Black male students. Critical literacy as a theoretical framework and critical discourse analysis (CDA) as a methodology are employed to advance battle rap as an effective instructional tool. Ultimately, this study seeks to privilege the educational experiences of Black male students and complex our interpretations of how language, literacy, and culture intersect and can be exercised in US classrooms

Relaxation, dephasing, and quantum control of electron spins in double quantum dots

Recent experiments have demonstrated quantum manipulation of two-electron spin states in double quantum dots using electrically controlled exchange interactions. Here, we present a detailed theory for electron spin dynamics in two-electron double dot systems that was used to guide these experiments and analyze experimental results. The theory treats both charge and spin degrees of freedom on an equal basis. Specifically, we analyze the relaxation and dephasing mechanisms that are relevant to experiments and discuss practical approaches for quantum control of two-electron system. We show that both charge and spin dephasing play important roles in the dynamics of the two-spin system, but neither represents a fundamental limit for electrical control of spin degrees of freedom in semiconductor quantum bits.Comment: 18 pages, 10 figures (reduced in length from V1, removed extraneous content, added references

Age Composition and Distribution of Red Drum (Sciaenops ocellatus) in Offshore Waters of the North Central Gulf of Mexico: An Evaluation of a Stock Under a Federal Harvest Moratorium

Because of a lack of fishery- dependent data, assessment of the recovery of fish stocks that undergo the most aggressive form of management, namely harvest moratoriums, remains a challenge. Large schools of red drum (Sclaenops ocellatus) were common along the northern Gulf of Mexico until the late 1980s when increased fishing effort quickly depleted the stock. After 24 years of harvest moratorium on red drum in federal waters, the stock is in need of reassessment; however, fishery dependent data are not available in federal waters and fishery-independent data are limited. We document the distribution, age composition, growth, and condition of red drum in coastal waters of the north central Gulf of Mexico, using data collected from a nearshore, randomized, bottom longline survey. Age composition of the fishery-independent catch indicates low mortality offish age 6 and above and confirms the effectiveness of the federal fishing moratorium. Bottom longline surveys may be a cost-effective method for developing fishery-independent indices for red drum provided additional effort can be added to nearshore waters (\u3c20 m depth). As with most stocks under harvest bans, effective monitoring of the recovery of red drum will require the development of fishery-independent indices. With limited economic incentive to evaluate non-exploited stocks, the most cost-effective approach to developing such monitoring is expansion of existing fishery independent surveys. We examine this possibility for red drum in the Gulf of Mexico and recommend the bottom longline survey conducted by the National Marine Fisheries Service expand effort in nearshore areas to allow for the development of long-term abundance indices for red drum

Latched Detection of Excited States in an Isolated Double Quantum Dot

Pulsed electrostatic gating combined with capacitive charge sensing is used to perform excited state spectroscopy of an electrically isolated double-quantum-dot system. The tunneling rate of a single charge moving between the two dots is affected by the alignment of quantized energy levels; measured tunneling probabilities thereby reveal spectral features. Two pulse sequences are investigated, one of which, termed latched detection, allows measurement of a single tunneling event without repetition. Both provide excited-state spectroscopy without electrical contact to the double-dot system.Comment: related papers available at http://marcuslab.harvard.ed

Mercury abundance and isotopic composition indicate subaerial volcanism prior to the end-Archean “whiff” of oxygen

Funding: This study was supported by National Aeronautics and Space Administration Exobiology Grant NNX16AI37G (R.B.) and by the MacArthur Professorship (J.D.B.) at the University of Michigan. M.A.K. acknowledges support from an Agouron Institute postdoctoral fellowship.Earth’s early atmosphere witnessed multiple transient episodes of oxygenation before the Great Oxidation Event 2.4 billion years ago (Ga) [e.g., A. D. Anbar et al., Science 317, 1903–1906 (2007); M. C. Koehler, R. Buick, M. E. Barley, Precambrian Res. 320, 281–290 (2019)], but the triggers for these short-lived events are so far unknown. Here, we use mercury (Hg) abundance and stable isotope composition to investigate atmospheric evolution and its driving mechanisms across the well-studied “whiff” of O2 recorded in the ∼2.5-Ga Mt. McRae Shale from the Pilbara Craton in Western Australia [A. D. Anbar et al., Science 317, 1903–1906 (2007)]. Our data from the oxygenated interval show strong Hg enrichment paired with slightly negative Δ199Hg and near-zero Δ200Hg, suggestive of increased oxidative weathering. In contrast, slightly older beds, which were evidently deposited under an anoxic atmosphere in ferruginous waters [C. T. Reinhard, R. Raiswell, C. Scott, A. D. Anbar, T. W. Lyons, Science 326, 713–716 (2009)], show Hg enrichment coupled with positive Δ199Hg and slightly negative Δ200Hg values. This pattern is consistent with photochemical reactions associated with subaerial volcanism under intense UV radiation. Our results therefore suggest that the whiff of O2 was preceded by subaerial volcanism. The transient interval of O2 accumulation may thus have been triggered by diminished volcanic O2 sinks, followed by enhanced nutrient supply to the ocean from weathering of volcanic rocks causing increased biological productivity.PostprintPeer reviewe

Singlet-triplet spin blockade and charge sensing in a few-electron double quantum dot

Singlet-triplet spin blockade in a few-electron lateral double quantum dot is investigated using simultaneous transport and charge-sensing measurements. Transport from the (1,1) to the (0,2) electron occupancy states is strongly suppressed relative to the opposite bias [(0,2) to (1,1)]. At large bias, spin blockade ceases as the (0,2) triplet state enters the transport window, giving a direct measure of exchange splitting as a function of magnetic field. A simple model for current and steady-state charge distribution in spin-blockade conditions is developed and found to be in excellent agreement with experiment.Comment: related papers available at http://marcuslab.harvard.ed

Biogenic carbonate mercury and marine temperature records reveal global influence of Late Cretaceous Deccan Traps

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155784/1/Meyer_et_al_2019_Biogenic_carbonate_mercury.pd

Epitaxy of Semiconductor-Superconductor nanowires

Controlling the properties of semiconductor/metal interfaces is a powerful method for designing functionality and improving the performance of electrical devices. Recently semiconductor/superconductor hybrids have appeared as an important example where the atomic scale uniformity of the interface plays a key role for the quality of the induced superconducting gap. Here we present epitaxial growth of semiconductor-metal core-shell nanowires by molecular beam epitaxy, a method that provides a conceptually new route to controlled electrical contacting of nanostructures and for designing devices for specialized applications such as topological and gate-controlled superconducting electronics. Our materials of choice, InAs/Al, are grown with epitaxially matched single plane interfaces, and alternative semiconductor/metal combinations allowing epitaxial interface matching in nanowires are discussed. We formulate the grain growth kinetics of the metal phase in general terms of continuum parameters and bicrystal symmetries. The method realizes the ultimate limit of uniform interfaces and appears to solve the soft-gap problem in superconducting hybrid structures.Comment: Combined text and Supplementary Informatio