3,812 research outputs found
The Diversion of Diversity: Uncovering the Antiblackness of Diversity Initiatives
In more recent years, Diversity has been a driving force in universities across the country. As underrepresented groups in the United States have gained more traction in the political and legal realms, they have gained the agency and the ability to advocate for their inclusion in institutions and structures that previously denied their access. This gaining of agency within these public realms is what has fueled higher education institutions across the country to really push for diversity, in both their faculty and student populations. The ideology behind this push is multiculturalism or multiracialism; this idea by its premise, the inclusion and appreciation of all cultures and races within a society, seems inherently beneficial and benevolent. However, by holding Multiculturalism/Diversity up and viewing it through a critical lens, I aim to illuminate how its application in higher education institutions such as Bucknell University, University of California, and Yale University, continues to isolate, exclude, and degrade African Americans
Flux-balance laws in scalar self-force theory
The motion of a radiating point particle can be represented by a series of
geodesics whose "constants" of motion evolve slowly with time. The evolution of
these constants of motion can be determined directly from the self-force
equations of motion. In the presence of spacetime symmetries, the situation
simplifies: there exist not only constants of motion conjugate to these
symmetries, but also conserved currents whose fluxes can be used to determine
their evolution. Such a relationship between point-particle motion and fluxes
of conserved currents is a flux-balance law. However, there exist constants of
motion that are not related to spacetime symmetries, the most notable example
of which is the Carter constant in the Kerr spacetime. In this paper, we first
present a new approach to flux-balance laws for spacetime symmetries, using the
techniques of symplectic currents and symmetry operators, which can also
generate more general conserved currents. We then derive flux-balance laws for
all constants of motion in the Kerr spacetime, using the fact that the
background, geodesic motion is integrable. For simplicity, we restrict
derivations in this paper to the scalar self-force problem. While generalizing
the discussion in this paper to the gravitational case will be straightforward,
there will be additional complications in turning these results into a
practical flux-balance law in this case.Comment: 15+3 pages, 1 figure; v2: corrected typos and added appendix and
figure, "matches" published versio
Permeability Analysis of Additively-Manufactured Wick Structures with Heat Exchanger Applications
Heat pipes and other heat transfer applications use capillary-driven liquid motion to enhance performance. This research uses water and a low surface tension fluid FC-40 to test additive-manufactured polymer wicks using a rateof-rise test. The rate-of-rise tests give a measure of the wicks’ performance capabilities as well as being able to calculate the wicks’ permeability and effective pore radius. Four wicks were measured having two different internal structures (i.e., 1.0 mm triangle and 1.75 mm square) and two external structures (i.e., layered and column). The 1.0 mm Triangle wicks performed better than their 1.0 mm Square counterparts for both water and FC-40. Both 1.0 mm Triangle wicks performed similarly for both water and FC-40, with the column wick (11.0 mm) performing better than the layered wick (8.98 mm). Using a least squares method from the rate-of-rise results, the permeability and effective pore radius of each wick were calculated for the 1.0 mm triangle layered wick, the 1.75 mm square layered wick, and the 1.0 mm triangle column wick. The 1.75 mm square column wick was unable to wick either liquid, so the permeability and effective pore radius were not able to be calculated. The permeability and effective pore radius for each wick were 3.00 um2 and 130.1 um, 0.95 um2 and 221.1 um, and 77.8 um2 and 1099 um, respectively. Some challenges involved with polymer additive manufacturing design and creation were also discussed
Flood Mapping of Recent Major Hurricane Events with Synthetic Aperture Radar, Commercial Imaging, and Aerial Observations
Floodwater mapping is an important remote sensing process that is used for disaster response, recovery, and damage assessment practices. Developing a system to read in Synthetic Aperture Radar (SAR) data and perform land cover classification will allow for the production of near real-time inundation mapping, enabling government and emergency response entities to get a preliminary idea of the situation. SAR is a unique remote sensing tool. Data in this project was obtained by NASA Jet Propulsion Laboratorys Uninhabited Aerial Vehicle SAR (UAVSAR), an L-band radar mounted to a Gulfstream III jet. Data collected by UAVSAR is similar to what will be available from the NASA-Indian Space Research Organization (NISAR) mission starting in early 2022. Using Python and ArcGIS applications, a model was developed using training samples taken from NOAA post-event aerial photography and UAVSAR data gathered in the aftermath of Hurricane Florence in September 2018
Alternative flow equation for the functional renormalization group
We derive an alternative to the Wetterich-Morris-Ellwanger equation by means of the two-particle irreducible (2PI) effective action, exploiting the method of external sources due to Garbrecht and Millington. The latter allows the two-point source of the 2PI effective action to be associated consistently with the regulator of the renormalization group flow. We show that this procedure leads to a flow equation that differs from that obtained in the standard approach based on the average one-particle irreducible effective action
Undoing a weak quantum measurement of a solid-state qubit
We propose an experiment which demonstrates the undoing of a weak continuous
measurement of a solid-state qubit, so that any unknown initial state is fully
restored. The undoing procedure has only a finite probability of success
because of the non-unitary nature of quantum measurement, though it is
accompanied by a clear experimental indication of whether or not the undoing
has been successful. The probability of success decreases with increasing
strength of the measurement, reaching zero for a traditional projective
measurement. Measurement undoing (``quantum un-demolition'') may be interpreted
as a kind of a quantum eraser, in which the information obtained from the first
measurement is erased by the second measurement, which is an essential part of
the undoing procedure. The experiment can be realized using quantum dot
(charge) or superconducting (phase) qubits.Comment: 5 page
A Sub-Type of Familial Pancreatic Cancer: Evidence and Implications of Loss-of-Function Polymorphisms in Indoleamine-2,3-Dioxygenase-2.
BACKGROUND: Variation in an individual\u27s genetic status can impact the development of pancreatic ductal adenocarcinoma; however, the majority of familial pancreatic cancers (FPC) cannot yet be attributed to a specific inherited mutation. We present data suggesting a correlation between loss-of-function single nucleotide polymorphisms (SNPs) in an immune regulator gene, indoleamine-2,3-dioxygenase-2 (IDO2), and an increased risk of FPC.
STUDY DESIGN: Germline DNA from patients who underwent resection for pancreatic ductal adenocarcinoma (n = 79) was sequenced for the IDO2 SNPs R248W and Y359Stop. Genotypes resulting in inactivation of IDO2 (Y325X homozygous, R248W homozygous) were labeled as homozygous, and the other genotypes were grouped as wild-type or heterozygous. Genotype distributions of each SNP were analyzed for Hardy-Weinberg deviation. A genotype frequency set from the 1000 Genomes Project (n = 99) was used as a genetic control for genotype distribution comparisons.
RESULTS: A significant 2-fold increase in the overall prevalence of the Y359Stop homozygous genotype compared with the expected Hardy-Weinberg equilibrium was noted (p \u3c 0.05). Familial pancreatic cancer was noted in 15 cases (19%) and comparison of the FPC cohort set to the genetic control set showed a 3-fold increase in Y359Stop homozygous rates (p = 0.054). Overall in our cohort, the homozygous genotype group was associated with increased risk of FPC (odds ratio 5.4; 95% CI 1.6 to 17.6; p \u3c 0.01). Sex, age at diagnosis, and history of tobacco use were not found to be significantly associated with FPC.
CONCLUSIONS: Our preliminary data suggest a strong association between the IDO2 inactivating Y359Stop SNP and an increased risk of FPC when compared with the control group. Future studies will evaluate the value of IDO2 genotyping as a prognostic, early detection marker for pancreatic ductal adenocarcinoma and a predictive marker for novel immune checkpoint therapies
On the Energy-Momentum Tensor of the Scalar Field in Scalar--Tensor Theories of Gravity
We study the dynamical description of gravity, the appropriate definition of
the scalar field energy-momentum tensor, and the interrelation between them in
scalar-tensor theories of gravity. We show that the quantity which one would
naively identify as the energy-momentum tensor of the scalar field is not
appropriate because it is spoiled by a part of the dynamical description of
gravity. A new connection can be defined in terms of which the full dynamical
description of gravity is explicit, and the correct scalar field
energy-momentum tensor can be immediately identified. Certain inequalities must
be imposed on the two free functions (the coupling function and the potential)
that define a particular scalar-tensor theory, to ensure that the scalar field
energy density never becomes negative. The correct dynamical description leads
naturally to the Einstein frame formulation of scalar-tensor gravity which is
also studied in detail.Comment: Submitted to Phys. Rev D15, 10 pages. Uses ReVTeX macro
Examining whether the information-motivation-behavioral skills model predicts medication adherence for patients with a rare disease.
The information-motivation-behavioral skills (IMB) model has been used to explain and promote medication adherence among patients with diabetes and HIV. The objective of this study was to examine whether the IMB model predicted medication adherence among vasculitis patients. Adult vasculitis patients (n=228) completed online questionnaires at baseline and 3-month follow-up. Linear regressions were calculated to determine the direct effects of information and motivation on medication adherence (P<0.05). A mediation analysis using a bootstrapping approach was used to test whether behavioral skills significantly mediated the effect of information and motivation on medication adherence. Participants reported high levels of information (M=4.0; standard deviation [SD]=0.68), moderate levels of motivation (M=2.7; SD=1.00), and high levels of behavioral skills (M=4.1; SD=0.74). In the regression model, only behavioral skills (B=0.38; P<0.001) were significantly associated with medication adherence; however, mediation analysis revealed that behavioral skills significantly mediated the effects of information and motivation on medication adherence. The results support the IMB-hypothesized relationships between information, motivation, behavioral skills, and medication adherence in our sample. Findings suggest that providers should work with vasculitis patients to increase their medication-related skills to improve medication adherence
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