5,657 research outputs found

    Measuring and Correcting Response Heaping Arising From the Use of Prototypes

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    Imprecision in respondent recall can cause response heaping in frequency data for particular values (e.g., 5, 10, 15). In human dimensions research, heaping can occur for variables such as days of participation (e.g., hunting, fishing), animals/fish harvested, or money spent on licenses. Distributions with heaps can bias population estimates because the means and totals can be inflated or deflated. Because bias can result in poor management decisions, determining if the bias is large enough to matter is important. This note introduces the logic and flow of a deheaping program that estimates bias in means and totals when people use approximate responses (i.e., prototypes). The program can make estimates even when spikes occur due to bag limits. The program is available online, and smooths heaps at multiples of 5 (numbers ending in 5 and 0) and 7 (e.g., 7, 14, 21), and produces standard deviations in estimates

    Clarifications of a Datum Axis or Centerplane Specifying in Maximum Material Condition of Geometric Dimensioning and Tolerancing

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    Engineering and Engineering Technology students and professionals learning the processes and standards in computer-aided design (CAD) and computer-aided manufacturing (CAM) should learn and understand the methodology of geometric dimensioning and tolerancing (GD&T) to describe the intent and requirements for part and assembly geometries. Correct application of GD&T ensures that the part and assembly geometry defined on the drawing will have the desired form and fit (within limits) and function as intended. One learning difficulty in understanding GD&T is the concept of defining a datum axis or center plane using Maximum Material Condition (MMC). To overcome this difficulty, a new approach is presented that uses a modifier â—‹V (Virtual Condition) instead of â—‹M (MMC). A thorough rationalization of using â—‹V in datum axis specification is discussed. The paper also provides a convenient table on how to use this modifier

    A quantum mechanical model of the upper bounds of the cascading contribution to the second hyperpolarizability

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    Microscopic cascading of second-order nonlinearities between two molecules has been proposed to yield an enhanced third-order molecular nonlinear-optical response. In this contribution, we investigate the two-molecule cascaded second hyperpolarizability and show that it will never exceed the fundamental limit of a single molecule with the same number of electrons as the two-molecule system. We show the apparent divergence behavior of the cascading contribution to the second hyperpolarizability vanishes when properly taking into account the intermolecular interactions. Although cascading can never lead to a larger nonlinear-optical response than a single molecule, it provides alternative molecular design configurations for creating materials with large third-order susceptibilities that may be difficult to design into a single molecule.Comment: 13 pages, 9 figures, 1 tabl

    Disrepair, Displacement and Distress: Finding Housing Stories Through Data Visualizations

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    While the COVID-19 pandemic is at its forefront a health crisis, it also triggered an upheaval in the already dire housing situation endured by many New York City renters. Tenant fears of rent increases, deferred maintenance, and displacement certainly worsened during the pandemic. But the housing crisis is, at the same time, part of a perpetual real estate cycle contingent on speculation and the symbiotic relationship of landlords, investors, and lenders in pursuit of profit – to the detriment of tenants. Following years of lending deregulation, funding cuts, and tax reform, the financialization of housing emerged. Real estate speculation, where housing is regarded as a commodity and a source of investment, runs on risk. Investors scout out locations where they foresee large-scale changes, such as rezoning and infrastructure development, and buy and sell properties in and around the area with the intent of maximizing their assets. With these considerations, this project uses a dataset of the expenses and incomes of select New York City landlords to explore how data visualizations can be used to navigate through the data points; and identify potential occurrences of property speculation, with the aim of finding personal stories of people and families living in a city of persistent precarity

    Single institution implementation of permanent 131Cs interstitial brachytherapy for previously irradiated patients with resectable recurrent head and neck carcinoma

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    Purpose: Permanent interstitial brachytherapy is an appealing treatment modality for patients with locoregional recurrent, resectable head and neck carcinoma (HNC), having previously received radiation. Cesium-131 (131Cs) is a permanent implant brachytherapy isotope, with a low average photon energy of 30 keV and a short half-life of 9.7 days. Exposure to medical staff and family members is low; patient isolation and patient room shielding are not required. This work presents a single institution’s implementation process of utilizing an intraoperative, permanent 131Cs implant for patients with completely resected recurrent HNC. Materials & Methods: Fifteen patients receiving 131Cs permanent seed brachytherapy were included in this analysis. The process of pre-planning, selecting the dose prescription, seed ordering, intraoperative procedures, post-implant planning, and radiation safety protocols are described. Results: Tumor volumes were contoured on the available preoperative PET/CT scans and a pre-implant treatment plan was created using uniform source strength and uniform 1 cm seed spacing. Implants were performed intraoperatively, following tumor resection. In five of the fifteen cases, intraoperative findings necessitated a change from the planned number of seeds and recalculation of the pre-implant plan. The average prescription dose was 56.1 ±6.6 Gy (range, 40-60 Gy). The average seed strength used was 2.2 ±0.2 U (3.5 ±0.3 mCi). Patients returned to a recovery room on a standard surgical floor and remained inpatients, without radiation safety restrictions, based on standard surgical recovery protocols. A post-implant treatment plan was generated based on immediate post-operative CT imaging to verify the seed distribution and confirm delivery of the prescription dose. Patients were provided educational information regarding radiation safety recommendations. Conclusions: Cesium-131 interstitial brachytherapy is feasible and does not pose major radiation safety concerns; it should be considered as a treatment option for previously irradiated patients with recurrent, resectable HNC
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