Evaluation of light-gauge metal diaphragm behavior and the diaphragms interaction with post frames

Light-gauge steel sheeted diaphragms on wood frames may be used to transfer in-plane shear forces to the end walls in post frame structures. The amount of shear force transferred is dependent upon the in-plane stiffness of the diaphragm and the frame stiffness;The results of 31 full-scale cantilever diaphragm tests are presented. Two different sheet profiles and three fastener patterns were used. The results are compared with the predicted stiffness from a plane truss computer analog. Test variables include openings in the sheeting, recessing of purlins in from the sheet ends, seams in the length of the sheet and placing the purlins flat;An analytical method and an empirical equation to be used in conjunction with testing are presented. The analytical method predicts the stiffness of the control diaphragms within 1.5% of that predicted by the plane truss computer analog. The empirical equation was fitted to steel diaphragms on steel frames and can be used to adjust for different diaphragm lengths, purlin spacings, and sheet thicknesses;It was found that the location and size of an opening does influence diaphragm stiffness. Openings with sheeting on two sides only will reduce diaphragm stiffness approximately twice as much as openings with sheeting on three or four sides. Fastener stiffness and location have the largest impact on diaphragm stiffness. Increasing the number of fasteners at seams in the length of the diaphragm will off-set the effect of the discontinuous sheet length. Fasteners near the edge of the sheet have a much larger impact on stiffness than those near the center of the sheet. The plane truss computer analog predicted the test diaphragm stiffness reasonably well;Several methods of modeling the diaphragm frame interaction are reviewed. It was found that the plane frame/truss model will model frame-diaphragm interaction more accurately for complex structural systems if the diaphragms are represented by two spring elements. Also varying frame and diaphragm stiffness can be included easily

Mesoamerican urbanism revisited: environmental change, adaptation, resilience, persistence, and collapse

Urban adaptation to climate change is a global challenge requiring a broad response that can be informed by how urban societies in the past responded to environmental shocks. Yet, interdisciplinary efforts to leverage insights from the urban past have been stymied by disciplinary silos and entrenched misconceptions regarding the nature and diversity of premodern human settlements and institutions, especially in the case of prehispanic Mesoamerica. Long recognized as a distinct cultural region, prehispanic Mesoamerica was the setting for one of the world’s original urbanization episodes despite the impediments to communication and resource extraction due to the lack of beasts of burden and wheeled transport, and the limited and relatively late use of metal implements. Our knowledge of prehispanic urbanism in Mesoamerica has been significantly enhanced over the past two decades due to significant advances in excavating, analyzing, and contextualizing archaeological materials. We now understand that Mesoamerican urbanism was as much a story about resilience and adaptation to environmental change as it was about collapse. Here we call for a dialogue among Mesoamerican urban archaeologists, sustainability scientists, and researchers interested in urban adaptation to climate change through a synthetic perspective on the organizational diversity of urbanism. Such a dialogue, seeking insights into what facilitates and hinders urban adaptation to environmental change, can be animated by shifting the long-held emphasis on failure and collapse to a more empirically grounded account of resilience and the factors that fostered adaptation and sustainability.000000000000000000000000000000000000000000000000000000201901 - Society for American Archaeologyhttps://www.pnas.org/doi/10.1073/pnas.2211558120Published versio

Mesoamerican urbanism revisited: Environmental change, adaptation, resilience, persistence, and collapse

Urban adaptation to climate change is a global challenge requiring a broad response that can be informed by how urban societies in the past responded to environmental shocks. Yet, interdisciplinary efforts to leverage insights from the urban past have been stymied by disciplinary silos and entrenched misconceptions regarding the nature and diversity of premodern human settlements and institutions, especially in the case of prehispanic Mesoamerica. Long recognized as a distinct cultural region, prehispanic Mesoamerica was the setting for one of the world’s original urbanization episodes despite the impediments to communication and resource extraction due to the lack of beasts of burden and wheeled transport, and the limited and relatively late use of metal implements. Our knowledge of prehispanic urbanism in Mesoamerica has been significantly enhanced over the past two decades due to significant advances in excavating, analyzing, and contextualizing archaeological materials. We now understand that Mesoamerican urbanism was as much a story about resilience and adaptation to environmental change as it was about collapse. Here we call for a dialogue among Mesoamerican urban archaeologists, sustainability scientists, and researchers interested in urban adaptation to climate change through a synthetic perspective on the organizational diversity of urbanism. Such a dialogue, seeking insights into what facilitates and hinders urban adaptation to environmental change, can be animated by shifting the long-held emphasis on failure and collapse to a more empirically grounded account of resilience and the factors that fostered adaptation and sustainability

Study of the reaction e^{+}e^{-} -->J/psi\pi^{+}\pi^{-} via initial-state radiation at BaBar

We study the process $e^+e^-\to J/\psi\pi^{+}\pi^{-}$ with initial-state-radiation events produced at the PEP-II asymmetric-energy collider. The data were recorded with the BaBar detector at center-of-mass energies 10.58 and 10.54 GeV, and correspond to an integrated luminosity of 454 $\mathrm{fb^{-1}}$. We investigate the $J/\psi \pi^{+}\pi^{-}$ mass distribution in the region from 3.5 to 5.5 $\mathrm{GeV/c^{2}}$. Below 3.7 $\mathrm{GeV/c^{2}}$ the $\psi(2S)$ signal dominates, and above 4 $\mathrm{GeV/c^{2}}$ there is a significant peak due to the Y(4260). A fit to the data in the range 3.74 -- 5.50 $\mathrm{GeV/c^{2}}$ yields a mass value $4244 \pm 5$ (stat) $\pm 4$ (syst)$\mathrm{MeV/c^{2}}$ and a width value $114 ^{+16}_{-15}$ (stat)$\pm 7$(syst)$\mathrm{MeV}$ for this state. We do not confirm the report from the Belle collaboration of a broad structure at 4.01 $\mathrm{GeV/c^{2}}$. In addition, we investigate the $\pi^{+}\pi^{-}$ system which results from Y(4260) decay

Extrinsic Rewards and Intrinsic Motives: Standard and Behavioral Approaches to Agency and Labor Markets

Employers structure pay and employment relationships to mitigate agency problems. A large literature in economics documents how the resolution of these problems shapes personnel policies and labor markets. For the most part, the study of agency in employment relationships relies on highly stylized assumptions regarding human motivation, e.g., that employees seek to earn as much money as possible with minimal effort. In this essay, we explore the consequences of introducing behavioral complexity and realism into models of agency within organizations. Specifically, we assess the insights gained by allowing employees to be guided by such motivations as the desire to compare favorably to others, the aspiration to contribute to intrinsically worthwhile goals, and the inclination to reciprocate generosity or exact retribution for perceived wrongs. More provocatively, from the standpoint of standard economics, we also consider the possibility that people are driven, in ways that may be opaque even to themselves, by the desire to earn social esteem or to shape and reinforce identity

When the Shoe is on the Other Foot: Experimental Evidence on Evaluation Disparities

Research provides evidence that the method chosen to elicit value has an important effect on a person’s valuation. We hypothesize that role has a crucial effect on decision makers’ elicited values: Buyers prefer to pay less and sellers prefer to collect more. We conduct experimental sessions and replicate the disparity between willingness to pay and willingness to accept. We conduct additional sessions in which role is stripped away: Endowed decision makers provide values that are used to determine a price at which anonymous others transact. Importantly, decision makers’ earnings in the experiment are not affected by the elicited values, but the endowments influence decision makers’ valuations. Our findings suggest that decision makers consider their relative standing, in comparison to anonymous others, in providing valuations. The disparity between willingness to pay and willingness to accept disappears when decision makers’ endowments ensure that they are at least as well off as other participants