Internal stress wave measurements in solids subjected to lithotripter pulses

Semiconductor strain gauges were used to measure the internal strain along the axes of spherical and disk plaster specimens when subjected to lithotripter shock pulses. The pulses were produced by one of two lithotripters. The first source generates spherically diverging shock waves of peak pressure approximately 1 MPa at the surface of the specimen. For this source, the incident and first reflected pressure (P) waves in both sphere and disk specimens were identified. In addition, waves reflected by the disk circumference were found to contribute significantly to the strain fields along the disk axis. Experimental results compared favorably to a ray theory analysis of a spherically diverging shock wave striking either concretion. For the sphere, pressure contours for the incident P wave and caustic lines were determined theoretically for an incident spherical shock wave. These caustic lines indicate the location of the highest stresses within the sphere and therefore the areas where damage may occur. Results were also presented for a second source that uses an ellipsoidal reflector to generate a 30-MPa focused shock wave, more closely approximating the wave fields of a clinical extracorporeal lithotripter

Nowhere minimal CR submanifolds and Levi-flat hypersurfaces

A local uniqueness property of holomorphic functions on real-analytic nowhere minimal CR submanifolds of higher codimension is investigated. A sufficient condition called almost minimality is given and studied. A weaker necessary condition, being contained a possibly singular real-analytic Levi-flat hypersurface is studied and characterized. This question is completely resolved for algebraic submanifolds of codimension 2 and a sufficient condition for noncontainment is given for non algebraic submanifolds. As a consequence, an example of a submanifold of codimension 2, not biholomorphically equivalent to an algebraic one, is given. We also investigate the structure of singularities of Levi-flat hypersurfaces.Comment: 21 pages; conjecture 2.8 was removed in proof; to appear in J. Geom. Ana

New rapid-curing, stable polyimide polymers with high-temperature strength and thermal stability

Additive-type polymerization reaction forms thermally stable polyimide polymers, thereby eliminating the volatile matter attendant with the condensation reaction. It is based on the utilization of reactive alicyclic rings positioned on the ends of polyimide prepolymers having relatively low molecular weights

Reinforced structural plastics

Reinforced polyimide structures are described. Reinforcing materials are impregnated with a suspension of polyimide prepolymer and bonded together by heat and pressure to form a cured, hard-reinforced, polyimide structure

Discriminating among interpretations for the X(2900) states

We make predictions for the production and decays of $X(2900)$ states, and their possible charged partners, in $B^+$ and $B^0$ decays, considering a number of competing models for the states, including triangle diagrams mediated by quark exchange or pion exchange, and resonance scenarios including molecules and tetraquarks. Assuming only isospin symmetry and the dominance of colour-favoured weak decays, we find characteristic differences in the predictions of the different models. Future experimental studies can therefore discriminate among the competing interpretations for the states.Comment: 13 pages, 3 figures. Version to appear in Phys.Rev.

Kinematical cusp and resonance interpretations of the X(2900)

We examine whether the LHCb vector $ud\bar{c}\bar{s}$ state $X(2900)$ can be interpreted as a kinematical cusp effect arising from $\bar D^*K^*$ and $\bar D_1 K^*$ interactions. The production amplitude is modelled as a triangle diagram with hadronic final state interactions. A satisfactory fit to the Dalitz plot projection is obtained that leverages the singularities of the production diagram without the need for $\bar{D}K$ resonances. A somewhat better fit is obtained if the final state interactions are strong enough to generate resonances, although the evidence in favour of this scenario is not conclusive.Comment: 10 pages, 3 figures. Version to appear in Physics Letters

A Review and Look Ahead at Criminalizing Pregnancy in the Name of State Interest in Fetal Life

Across the United States, and especially in communities that are highly policed and in places hostile to abortion, pregnant people are dying, suffering, being separated from their children and families, and going to jail and prison in purported service of the state interest in fetal life recognized in Roe v. Wade and expanded in Planned Parenthood of Pennsylvania v. Casey. This Article focuses on two common practices that cause these harms: criminalizing pregnant people and denying them medical decision-making authority. While these practices are not new, the U.S. Supreme Court’s decision in Dobbs v. Jackson Women’s Health Organization is accelerating them. With abortion returned to the states without a U.S. constitutional floor, the state interest in fetal life can go largely unchecked with respect to all pregnant people, not just those who need abortions. In this Article, we look back at several cases from the 1990s and early 2000s involving denials of medical decision-making authority and criminalization of pregnant people for substance use during pregnancy. We also discuss contemporary instances of these phenomenon, focusing on Alabama’s Child Chemical Endangerment Act and 1997 Wisconsin Act 292, both of which are currently and fervently used to punish pregnant people for actual or suspected substance use and which fail entirely to advance fetal or parental well-being. Based on our survey of these past and present cases, we reflect on several legal arguments and strategies to demand and restore full personhood for pregnant people. We link pregnancy criminalization to legally cognizable animus, observing that hallmark features of such animus abound when substance use during pregnancy is criminalized. We link environmental injustice to pregnancy criminalization, observing that it is irrational to punish and jail people for “polluting” the micro-environment of the womb in service of an interest in fetal life when all people—particularly the most policed—are perniciously, macro-environmentally exposed to toxins that impact reproduction and pregnancy. We reiterate that informed consent to medical treatment is the bedrock guarantee of healthcare and bodily autonomy—and pregnancy demands rather than diminishes this guarantee—and that drug tests without consent that lead to law enforcement consequences violate both this and the Fourth Amendment. We also very briefly emphasize that mandatory reporting of suspected child abuse or neglect based on a positive drug test fails to protect anyone and that mandatory reporters can challenge this obligation where it frustrates core professional duties. Together, all of these threads intersect to show that criminalizing pregnancy and denying pregnant people medical decision-making authority is about the social control and exclusion that punishment accomplishes. The impulse to control and exclude surely varies intersectionally, corresponding to the expectations and stereotypes about parenting applicable to the punished person or community. But in the end, in every case, no fetal life, no parental life, no family life, and no constitutional right or medical objective is protected or furthered when pregnancy is criminalized and pregnant people are denied medical decision-making authority