Economical technique for fragmentation testing

Automatic rifle was modified for remote, single-shot use. To simulate statistically--determined fragment size from rocket-motor casing blunt-nosed bullet was made of same alloy. Cartridge was loaded with enough powder to make bullet reach target at same estimated velocity as shrapnel from rocket casing

The Feigned Annoyance and Frustration Test to Activate the Sympathoadrenal Medullary System

When perceived as threatening, social interactions have been shown to trigger the sympathoadrenal medullary system as well as the hypothalamic-pituitary-adrenal axis resulting in a physiologic stress response. The allostatic load placed on human health and physiology in the context of acute and chronic stress can have profound health consequences. The purpose of this study was to develop a protocol for a lab-based stress stimulus using social-evaluative threat. While several valid, stress-stimulating protocols exist, we sought to develop one that triggered a physiologic response, did not require significant lab resources, and could be completed in around 10 min. We included 53 participants (29 men and 24 women) and exposed them to a modified version of the Stroop Color-Word Interference Task during which the participants were made to feel they were performing the task poorly while the lead researcher feigned annoyance and frustration. After exposure to this Feigned Annoyance and Frustration (FAF) Test, both the men and women in this study demonstrated a statistically significant and clinically meaningful increase in subjective stress on the visual analog scale. Additionally, the men in this study demonstrated a statistically significant increase in heart rate and salivary α-amylase concentrations after exposure to the test. The women in this study did not demonstrate a statistically significant increase in the physiologic stress biomarkers. This protocol for the FAF Test shows promise to researchers with limited time and resources who are interested in experimentally activating the sympathoadrenal medullary system

The Remains of the Fray: Nascent Colonialism and Heterogeneous Hybridity

Investigations at the Native American site complex of Stark Farms in Mississippi, USA, have yielded numerous examples of metal artifacts of European origin. Our study suggests that they derive from contact between the AD 1540–1541 winter encampment of the Spanish Hernando de Soto expedition and the local Indigenous polity. The artifacts display a wide range of modifications, uses, and depositional contexts congruent with hybrid practices. We argue that the early colonial setting of Stark Farms requires a different perspective on cultural mixing than is often applied in studies of European colonialism. This is highlighted by the strongly improvisational nature of the modification of the metal objects, embodying a political climate in which European incursions were precarious and in which hybridity and power were heterogeneous and fluid

How Patients\u27 Self-Disclosure about Sickle Cell Pain Episodes to Significant Others Relates to Living with Sickle Cell Disease

Objectives: This cross-sectional study examines to whom and how fully sickle cell disease (SCD) patients talk to others about sickle cell pain, how helpful it is to talk with others about these pain episodes, and the association between talking to others about sickle cell pain episodes and patients\u27 psychological adjustment and coping strategies in managing the disease. Methods: A convenience sample of 73 African American patients with SCD (30 men and 43 women), were recruited from two SCD clinics at the time of routine medical visits. Most participants had been diagnosed with hemoglobin SS, and they reported an average number of 8.61 pain episodes in the previous 12 months. Participants were asked to whom, how fully, and how helpful it was to talk to significant others about SCD pain episodes experienced in the last 12 months. Patients also completed measures of their psychological adjustment as well as how they would manage a future sickle cell pain episode. Self-report ratings were made on Likert-type scales. Results: Based on paired samples t-tests, participants talked significantly more fully about their thoughts and feelings concerning pain episodes to God and to their primary medical providers than to either their parents, siblings, or an intimate partner/close friend. Bivariate correlations indicated that amount and helpfulness of talking about pain episodes to God and to parents were significantly associated with better psychological adjustment on selected measures. Also, bivariate correlations indicated that helpfulness in talking with siblings, intimate partner/close friend, and primary medical providers was positively related with willingness to go to a physician in the event of a future pain episode. Conclusions: The results document to whom and how helpful it is to talk with others about SCD pain episodes and how SCD disclosure is related to strategies for managing this disease

Orientational Phase Transition in Na_{x}C_{60} (1

X-ray diffraction and calorimetry data on cubic NaxC60(1\u3cx60, e.g., Tm(x=1.3)=325 K. The ordered phases are the same as in pure C60: simple cubic, space group Pa3¯, but the orientations in the disordered phase are more restricted. We explain how Na stabilizes the ordered phase to rather high T, while K and Rb do not, in terms of Coulomb interactions between C60 molecules and and Na ions which we calculate from the local charge density of C60

Cryo-EM Structures of HIV-1 trimer bound to CD4-mimetics M48U1 and BNM-III-170 adopt a CD4-bound open conformation

Human Immunodeficiency Virus-1 (HIV-1), the causative agent of AIDS, impacts millions of people. Entry into target cells is mediated by the HIV-1 envelope (Env) glycoprotein interacting with host receptor CD4, which triggers conformational changes allowing binding to a coreceptor and subsequent membrane fusion. Small molecule or peptide CD4-mimetic drugs mimic CD4’s Phe43 interaction with Env by inserting into the conserved Phe43 pocket on Env subunit gp120. Here, we present single-particle cryo-EM structures of CD4-mimetics BNM-III-170 and M48U1 bound to a BG505 native-like Env trimer plus the CD4-induced antibody 17b at 3.7Å and 3.9Å resolution, respectively. CD4-mimetic-bound BG505 exhibits canonical CD4-induced conformational changes including trimer opening, formation of the 4-stranded gp120 bridging sheet, displacement of the V1V2 loop, and formation of a compact and elongated gp41 HR1C helical bundle. We conclude that CD4-induced structural changes on both gp120 and gp41 Env subunits are induced by binding to the gp120 Phe43 pocket

Collapsing Spaces, Colliding Places: Leveraging Constructs from Humanistic Geography to Explore Mathematics Classes

Humanistic geographers distinguish between space and place: “What begins as undifferentiated space becomes place as we get to know it better and endow it with value” (Tuan, 1977, page 6). In this essay, we seek to demonstrate how mathematics education researchers and mathematics instructors may find space and place illuminating for understanding important aspects of students’ learning experiences during the coronavirus pandemic—and possibly beyond. Specifically, after introducing the terms and relating them to the context of a university mathematics class, we exemplify how home and class places collided for three undergraduate mathematics students forced to deal with the abrupt transition to online education. We conclude by discussing implications of attending to space and place for designers and researchers of (pandemic) online instruction and make connections to how the pandemic and attending to space and place can serve as a catalyst for reshaping undergraduate mathematics education

Cosmic Censorship, Area Theorem, and Self-Energy of Particles

The (zeroth-order) energy of a particle in the background of a black hole is given by Carter's integrals. However, exact calculations of a particle's {\it self-energy} (first-order corrections) are still beyond our present reach in many situations. In this paper we use Hawking's area theorem in order to derive bounds on the self-energy of a particle in the vicinity of a black hole. Furthermore, we show that self-energy corrections {\it must} be taken into account in order to guarantee the validity of Penrose cosmic censorship conjecture.Comment: 11 page