679 research outputs found

    Marriage as Black Citizenship?

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    The narrative of black marriage as citizenship enhancing has been pervasive in American history. As we mark the fiftieth anniversary of the Moynihan Report and prepare to celebrate the 150th anniversary of Thirteenth Amendment, this Article argues that this narrative is one that we should resist. The complete story of marriage is one that involves racial subordination and caste. Even as the Supreme Court stands to extend marriage rights to LGBT couples, the Article maintains that we should embrace nonmarriage as a legitimate frame for black loving relationships—gay or straight. Nonmarriage might do just as much, if not more, to advance black civil rights. Part I explores marriage’s role in racial subordination by looking at the experiences of African Americans, as well as Native Americans, Puerto Ricans, and Asian Americans. Drawing on institutional structure analyses, it then considers how legal marriage has “married” Blacks to second-class citizenship. Part II explores the current place of marriage in African America. It argues that, while the regulation of black loving relationships today differs dramatically from what we saw in earlier times, family law often has a punitive effect on such American families. Part III contemplates the benefits of adopting a focus on nonmarriage. It contends that meeting black families where they are holds the most potential for progress in addressing the structural barriers to success faced by those families. The Article ends with a “call to action” for legal scholars and others concerned about black families and citizenship. It maps a broad agenda for exploring in earnest the potential that supporting and valuing the existing networks, arrangements, and norms regarding gender and caretaking in African America has for promoting black citizenship and equality in the twenty-first century

    Parenting While Black

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    Changes in law and policy—not to mention developments such as the COVID-19 pandemic and its devastating effects on families—raise important questions about how to define parental rights and how to best support parents and children during these challenging times. The Symposium also presented important questions about issues of race, gender, sexuality, and class in our modern context. Even more salient in this space are issues of race. Here, as in other contexts, Black families, like my grandmother’s and so many others, are the “canaries in the mine.” Their experiences provide us with important insight into the signs of danger facing Black and Brown families. To that extent, the concerns of families, like my grandmother’s, should be at the center of our discussion around families and the challenges they face in this moment. This Essay intervenes in the conversation hosted by the Fordham Law Review by focusing on issues of race, which, as I have indicated elsewhere, remain underexplored in family law scholarship.1 More specifically, it endeavors to give greater context to the term “parenting while Black,” which I utilized in the narrative that launched this iniquity. In the wake of George Floyd’s death at the hands of police in 2020,2 people of all walks of life are all too familiar with the phrase “driving, or even walking, while Black.”3 These phrases reference the scores of Black and Brown people killed or badly injured at the hands of white law enforcement officers, often when the need for such action was plainly unwarranted.4 In deploying the term “parenting while Black,” I mean to invoke not only the criminal justice context, but also all the systems that inform the functioning and well-being of families of color. Enumerating such systems provides us with a deeper appreciation of the obstacles that parents of color must navigate in trying to provide for their children

    Probing Nuclear forces beyond the drip-line using the mirror nuclei 16^{16}N and 16^{16}F

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    Radioactive beams of 14^{14}O and 15^{15}O were used to populate the resonant states 1/2+^+, 5/2+^+ and 0,1,20^-,1^-,2^- in the unbound 15^{15}F and 16^{16}F nuclei respectively by means of proton elastic scattering reactions in inverse kinematics. Based on their large proton spectroscopic factor values, the resonant states in 16^{16}F can be viewed as a core of 14^{14}O plus a proton in the 2s1/2_{1/2} or 1d5/2_{5/2} shell and a neutron in 1p1/2_{1/2}. Experimental energies were used to derive the strength of the 2s1/2_{1/2}-1p1/2_{1/2} and 1d5/2_{5/2}-1p1/2_{1/2} proton-neutron interactions. It is found that the former changes by 40% compared with the mirror nucleus 16^{16}N, and the second by 10%. This apparent symmetry breaking of the nuclear force between mirror nuclei finds explanation in the role of the large coupling to the continuum for the states built on an =0\ell=0 proton configuration.Comment: 6 pages, 3 figures, 2 tables, accepted for publication as a regular article in Physical Review

    New pathway to bypass the 15O waiting point

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    We propose the sequential reaction process 15^{15}O(pp,γ)(β+\gamma)(\beta^{+})16^{16}O as a new pathway to bypass of the 15^{15}O waiting point. This exotic reaction is found to have a surprisingly high cross section, approximately 1010^{10} times higher than the 15^{15}O(pp,β+\beta^{+})16^{16}O. These cross sections were calculated after precise measurements of energies and widths of the proton-unbound 16^{16}F low lying states, obtained using the H(15^{15}O,p)15^{15}O reaction. The large (p,γ)(β+)(p,\gamma)(\beta^{+}) cross section can be understood to arise from the more efficient feeding of the low energy wing of the ground state resonance by the gamma decay. The implications of the new reaction in novae explosions and X-ray bursts are discussed.Comment: submitte

    Effective Rheology of Bubbles Moving in a Capillary Tube

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    We calculate the average volumetric flux versus pressure drop of bubbles moving in a single capillary tube with varying diameter, finding a square-root relation from mapping the flow equations onto that of a driven overdamped pendulum. The calculation is based on a derivation of the equation of motion of a bubble train from considering the capillary forces and the entropy production associated with the viscous flow. We also calculate the configurational probability of the positions of the bubbles.Comment: 4 pages, 1 figur

    An all-solid-state laser source at 671 nm for cold atom experiments with lithium

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    We present an all solid-state narrow line-width laser source emitting 670mW670\,\mathrm{mW} output power at 671nm671\,\mathrm{nm} delivered in a diffraction-limited beam. The \linebreak source is based on a fre-quency-doubled diode-end-linebreak pumped ring laser operating on the 4F3/24I13/2{^4F}_{3/2} \rightarrow {^4I}_{13/2} transition in Nd:YVO4_4. By using periodically-poled po-tassium titanyl phosphate (ppKTP) in an external build-up cavity, doubling efficiencies of up to 86% are obtained. Tunability of the source over 100GHz100\,\rm GHz is accomplished. We demonstrate the suitability of this robust frequency-stabilized light source for laser cooling of lithium atoms. Finally a simplified design based on intra-cavity doubling is described and first results are presented

    Ab Initio Screening Approach for the Discovery of Lignin Polymer Breaking Pathways

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    The directed depolymerization of lignin biopolymers is of utmost relevance for the valorization or commercialization of biomass fuels. We present a computational and theoretical screening approach to identify potential cleavage pathways and resulting fragments that are formed during depolymerization of lignin oligomers containing two to six monomers. We have developed a chemical discovery technique to identify the chemically relevant putative fragments in eight known polymeric linkage types of lignin. Obtaining these structures is a crucial precursor to the development of any further kinetic modeling. We have developed this approach by adapting steered molecular dynamics calculations under constant force and varying the points of applied force in the molecule to diversify the screening approach. Key observations include relationships between abundance and breaking frequency, the relative diversity of potential pathways for a given linkage, and the observation that readily cleaved bonds can destabilize adjacent bonds, causing subsequent automatic cleavage.Massachusetts Institute of Technology (Research Support Corporation, Reed Grant)United States. Dept. of Energy. Computational Science Graduate Fellowship Program (DOE-CSGF)Burroughs Wellcome Fund (Career Award at the Scientific Interface

    Transverse sphericity of primary charged particles in minimum bias proton-proton collisions at s=0.9\sqrt{s}=0.9, 2.76 and 7 TeV

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    Measurements of the sphericity of primary charged particles in minimum bias proton--proton collisions at s=0.9\sqrt{s}=0.9, 2.76 and 7 TeV with the ALICE detector at the LHC are presented. The observable is linearized to be collinear safe and is measured in the plane perpendicular to the beam direction using primary charged tracks with pT0.5p_{\rm T}\geq0.5 GeV/c in η0.8|\eta|\leq0.8. The mean sphericity as a function of the charged particle multiplicity at mid-rapidity (NchN_{\rm ch}) is reported for events with different pTp_{\rm T} scales ("soft" and "hard") defined by the transverse momentum of the leading particle. In addition, the mean charged particle transverse momentum versus multiplicity is presented for the different event classes, and the sphericity distributions in bins of multiplicity are presented. The data are compared with calculations of standard Monte Carlo event generators. The transverse sphericity is found to grow with multiplicity at all collision energies, with a steeper rise at low NchN_{\rm ch}, whereas the event generators show the opposite tendency. The combined study of the sphericity and the mean pTp_{\rm T} with multiplicity indicates that most of the tested event generators produce events with higher multiplicity by generating more back-to-back jets resulting in decreased sphericity (and isotropy). The PYTHIA6 generator with tune PERUGIA-2011 exhibits a noticeable improvement in describing the data, compared to the other tested generators.Comment: 21 pages, 9 captioned figures, 3 tables, authors from page 16, published version, figures from http://aliceinfo.cern.ch/ArtSubmission/node/308

    Measurement of charm production at central rapidity in proton-proton collisions at s=2.76\sqrt{s} = 2.76 TeV

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    The pTp_{\rm T}-differential production cross sections of the prompt (B feed-down subtracted) charmed mesons D0^0, D+^+, and D+^{*+} in the rapidity range y<0.5|y|<0.5, and for transverse momentum 1<pT<121< p_{\rm T} <12 GeV/cc, were measured in proton-proton collisions at s=2.76\sqrt{s} = 2.76 TeV with the ALICE detector at the Large Hadron Collider. The analysis exploited the hadronic decays D0^0 \rightarrow Kπ\pi, D+^+ \rightarrow Kππ\pi\pi, D+^{*+} \rightarrow D0π^0\pi, and their charge conjugates, and was performed on a Lint=1.1L_{\rm int} = 1.1 nb1^{-1} event sample collected in 2011 with a minimum-bias trigger. The total charm production cross section at s=2.76\sqrt{s} = 2.76 TeV and at 7 TeV was evaluated by extrapolating to the full phase space the pTp_{\rm T}-differential production cross sections at s=2.76\sqrt{s} = 2.76 TeV and our previous measurements at s=7\sqrt{s} = 7 TeV. The results were compared to existing measurements and to perturbative-QCD calculations. The fraction of cdbar D mesons produced in a vector state was also determined.Comment: 20 pages, 5 captioned figures, 4 tables, authors from page 15, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/307
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