2,569 research outputs found
A two-way photonic interface for linking Sr+ transition at 422 nm to the telecommunications C-band
We report a single-stage bi-directional interface capable of linking Sr+
trapped ion qubits in a long-distance quantum network. Our interface converts
photons between the Sr+ emission wavelength at 422 nm and the telecoms C-band
to enable low-loss transmission over optical fiber. We have achieved both up-
and down-conversion at the single photon level with efficiencies of 9.4% and
1.1% respectively. Furthermore we demonstrate noise levels that are low enough
to allow for genuine quantum operation in the future.Comment: 5 pages, 4 figure
Myositis complicating benzathine penicillin-G injection in a case of rheumatic heart disease
Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND
license (http://creativecommons.org/licenses/by-nc-nd/4.0/).A 7-year old boy developed myositis secondary to intramuscular injection of benzathine penicillin-G in the context of secondary prophylaxis for rheumatic heart disease. Side effects of intramuscular delivery of benzathine penicillin-G are well described and include injection site pain and inflammation, but myositis, as depicted on magnetic resonance imaging in this case, has not previously been described
The Quintuple Quasar: Radio and Optical Observations
We present results from high-resolution radio and optical observations of PMN
J0134-0931, a gravitational lens with a unique radio morphology and an
extremely red optical counterpart. Our data support the theory of Keeton & Winn
(2003): five of the six observed radio components are multiple images of a
single quasar, produced by a pair of lens galaxies. Multi-frequency VLBA maps
show that the sixth and faintest component has a different radio spectrum than
the others, confirming that it represents a second component of the background
source rather than a sixth image. The lens models predict that there should be
additional faint images of this second source component, and we find evidence
for one of the predicted images. The previously-observed large angular sizes of
two of the five bright components are not intrinsic (which would have excluded
the possibility that they are lensed images), but are instead due to scatter
broadening. Both the extended radio emission observed at low frequencies, and
the intrinsic image shapes observed at high frequencies, can be explained by
the lens models. The pair of lens galaxies is marginally detected in HST
images. The differential extinction of the quasar images suggests that the
extreme red color of the quasar is at least partly due to dust in the lens
galaxies.Comment: ApJ, in press. 22 pp, 10 fig
The Prograde Orbit of Exoplanet TrES-2b
We monitored the Doppler shift of the G0V star TrES-2 throughout a transit of
its giant planet. The anomalous Doppler shift due to stellar rotation (the
Rossiter-McLaughlin effect) is discernible in the data, with a signal-to-noise
ratio of 2.9, even though the star is a slow rotator. By modeling this effect
we find that the planet's trajectory across the face of the star is tilted by
-9 +/- 12 degrees relative to the projected stellar equator. With 98%
confidence, the orbit is prograde.Comment: ApJ, in press [15 pages
Native Hawaiians in Engineering: A Path the Professoriate
In this paper and presentation, a research team of engineers and educators from the University of Hawai‘i at Mānoa will present early findings from a three-phase, mixed-methods study where they sought to understand the gaps in progression of Native Hawaiian students to an academic career in engineering. The study is grounded in Tinto’s integration framework and Bean’s student attrition models, in which authors look at persistence in higher education. Tinto and Bean both suggested that students are more likely to persist in college if they are connected to both the academic as well as social life. Where both Tinto and Bean were primarily studying
undergraduates, this study further explores the engineering graduate students' persistence, motivation, and the idea of connection to the Hawaiian culture. Furthermore, the study seeks to extends Bean’s work regarding higher education faculty where he suggested that intrinsic factors such as being true to self and valuing of students were essential characteristics for new faculty. One of the most underrepresented ethnic groups in engineering may be Native Hawaiians (NH). According to the 2011 US Census, the combined working population of NHs, Pacific Islanders, and ‘Other Race’ (grouped by U.S. Census due to small sample size) represents 4.6% of the total
U.S. workforce but only 1.4% of science, technology, engineering, and mathematics (STEM) occupations. This makes NHs and Pacific Islanders the most underrepresented ethnic groups in the nation in STEM employment. Additionally, the U.S. Census national data indicates that only 700 single-race NHs or other Pacific Islanders received doctoral degree in science, engineering, and health fields in 2008. First, selected data are shared from a 43-item undergraduate survey administered to engineering students asking about background and preparation to pursue engineering as a major (N=168). Barriers, support systems, financial aid, and self-perception of success between NH students (n=17) and non-NH students (n=151) differences and similarities will be discussed. Second, major themes that emerged from structured interviews with 6 of 8 NH engineering graduate students are presented, including a sense of belonging to their chosen major, past performance in academics, and family support, important factors for degree completion in underrepresented groups such as Hawaiians, Filipinos, African-American and Blacks Hispanics, and women in science, technology, engineering, and mathematics (STEM) fields. Third, a short description of a six-workshop series called A‘o in Engineering and research and teaching opportunities designed to support interested senior and graduate engineering students (N=20) will follow. The authors end with a proposed education model to increase NH career interest in the engineering professoriate
Extracorporeal membrane oxygenation support after the Fontan operation
ObjectiveExtracorporeal membrane oxygenation has been used to support children with cardiac failure after the Fontan operation. Mortality is high, and causes of mortality remain unclear. We evaluated the in-hospital mortality and factors associated with mortality in these patients.MethodsExtracorporeal Life Support Organization registry data on patients requiring extracorporeal membrane oxygenation after the Fontan operation from 1987 to 2009 were retrospectively analyzed. Demographics and extracorporeal membrane oxygenation data were compared for survivors and nonsurvivors. A multivariable logistic regression model was used to identify factors associated with mortality.ResultsOf 230 patients, 81 (35%) survived to hospital discharge. Cardiopulmonary resuscitation was more frequent (34% vs 17%, P = .04), and median fraction of inspired oxygen concentration was higher (1 [confidence interval, 0.9–1.0] vs 0.9 [confidence interval, 0.8–1.0], P = .03) before extracorporeal membrane oxygenation in nonsurvivors compared with survivors. Extracorporeal membrane oxygenation duration and incidence of complications, including surgical bleeding, neurologic injury, renal failure, inotrope use on extracorporeal membrane oxygenation, and bloodstream infection, were higher in nonsurvivors compared with survivors (P < .05 for all). In a multivariable model, neurologic injury (odds ratio, 5.18; 95% confidence interval, 1.97–13.61), surgical bleeding (odds ratio, 2.36; 95% confidence interval, 1.22–4.56), and renal failure (odds ratio, 2.81; 95% confidence interval, 1.41–5.59) increased mortality. Extracorporeal membrane oxygenation duration of more than 65 hours to 119 hours (odds ratio, 0.33; 95% confidence interval, 0.14–0.76) was associated with decreased mortality.ConclusionsCardiac failure requiring extracorporeal membrane oxygenation after the Fontan operation is associated with high mortality. Complications during extracorporeal membrane oxygenation support increase mortality odds. Prompt correction of surgical bleeding when possible may improve survival
Mathematical Analysis of a COVID-19 Compartmental Model with Interventions
Mathematical models of the COVID-19 pandemic have been utilized in a variety of settings as a core component of national public health responses. Often based on systems of ordinary differential equations; compartmental models are commonly used to understand and forecast outbreak trajectories. In view of the primarily applied nature of COVID-19 models; theoretical analysis can provide a global and long-term perspective of key model properties; and relevant insights about the infection dynamics they represent. This work formulates and undertakes such an investigation for a compartmental model of COVID-19; which includes the effect of interventions. More specifically; this paper analyzes the characteristics of the solutions of a compartmental model by establishing the existence and stability of the equilibrium points based on the value of the basic reproductive number R0. Our results provide insights on the possible policies that can be implemented to address the health crisis
2006 SQ372: A Likely Long-Period Comet from the Inner Oort Cloud
We report the discovery of a minor planet (2006 SQ372) on an orbit with a
perihelion of 24 AU and a semimajor axis of 796 AU. Dynamical simulations show
that this is a transient orbit and is unstable on a timescale of 200 Myrs.
Falling near the upper semimajor axis range of the scattered disk and the lower
semimajor axis range of the Oort Cloud, previous membership in either class is
possible. By modeling the production of similar orbits from the Oort Cloud as
well as from the scattered disk, we find that the Oort Cloud produces 16 times
as many objects on SQ372-like orbits as the scattered disk. Given this result,
we believe this to be the most distant long-period comet ever discovered.
Furthermore, our simulation results also indicate that 2000 OO67 has had a
similar dynamical history. Unaffected by the "Jupiter-Saturn Barrier," these
two objects are most likely long-period comets from the inner Oort Cloud
Northern SPIRIT Consortium - Canadian Collaboration through Student-Led CubeSat Constellation
The Northern Space Program for Innovative Research and Integrated Training (Northern SPIRIT) is a unique collaboration of three Canadian post-secondary institutions that will design, build, and operate a constellation of three CubeSats. The consortium, beginning in 2017, comprises Yukon University, Aurora College, and the University of Alberta (U of A). The partnership will develop three CubeSats: YukonSat (2U), AuroraSat (2U) and Ex-Alta 2 (3U) which will be launched into Low Earth Orbit in 2022. Northern SPIRIT strives to use space technology development to inspire motivated youth across Canada to engage in student-led collaboration and hands-on education, research, training, and to amplify Northern Canadian voices.
Supported by the Canadian Space Agency (CSA) through the Canadian CubeSat Project (CCP), Northern SPIRIT will help further the CSAs goal of making space more accessible throughout Canada. The constellation mission will support a range of educational payloads dedicated to the expansion of STEM, arts, and language outreach opportunities. They also introduce passionate k-12 students to hands-on experiences with space mission concepts such as operations, coding, and data analytics.
AuroraSat’s mission objective is educational outreach directed at sharing Northern art, languages, and history. Northern Images Mission will host a screen and an imager which will capture artwork created by Northern Artists backdropped by the Earth’s horizon. Northern Voices Mission will broadcast Northern Canadian stories of the space and sky, read by students, on amateur radio bands from all three satellites. Finally, the Northern Games Mission will transmit partial messages (focusing on Northern history) from the three satellites in select geographic zones, requiring global cooperation between amateur radio operators to decode a whole message.
YukonSat will provide the novel opportunity to expand the capacity of highly qualified space science personnel in the Yukon, while furthering space science engagement and education of the public. The satellite’s payload will host a robotic arm, an OLED screen, camera, and a sensor array for attitude determination. The robotic arm allows freedom to point remote sensing equipment without using the spacecraft attitude determination and control system. The OLED screen and camera will display and photograph student-made Northern art with the Earth and space in the background.
Ex-Alta 2 will host a multispectral imaging payload with the mission objective to study wildfires. A secondary science objective on all three satellites is space weather monitoring using a Digital Fluxgate Magnetometer that was designed and built at the U of A. In addition to this inter-institutional coordination, the U of A-designed 3U bus has been adapted into a 2U version to be used on the other two satellites in the constellation.
The partnership amongst the three institutions supports collaboration in remote communities across Provincial & Territorial borders, advancing Canada’s contribution to the space industry and showcasing the exciting possibilities for interdisciplinary, national partnership. Extending across Canada, the consortium strives to inspire and enable passionate students to celebrate the Canadian voice and pursue opportunities in the space industry. In partnership with the CSA, Northern SPIRIT is a frontrunner in the exciting upward trend of the democratization of space
The role of G protein gene GNB3 C825T Polymorphism in HIV-1 acquisition, progression and immune activation
<p>Abstract</p> <p>Background</p> <p>The <it>GNB3 C825T </it>polymorphism is associated with increased G protein-mediated signal transduction, SDF-1α-mediated lymphocyte chemotaxis, accelerated HIV-1 progression, and altered responses to antiretroviral therapy among Caucasian subjects. The <it>GNB3 </it>825T allele is highly prevalent in African populations, and as such any impact on HIV-1 acquisition or progression rates could have a dramatic impact. This study examines the association of the 825T polymorphism with HIV-1 acquisition, disease progression and immune activation in two African cohorts. <it>GNB3 </it>825 genotyping was performed for enrolees in both a commercial sex worker cohort and a perinatal HIV transmission (PHT) cohort in Nairobi, Kenya. <it>Ex vivo </it>immune activation was quantified by flow cytometry, and plasma chemokine levels were assessed by cytokine bead array.</p> <p>Results</p> <p><it>GNB3 </it>genotype was not associated with sexual or vertical HIV-1 acquisition within these cohorts. Within the Pumwani cohort, <it>GNB3 </it>genotype did not affect HIV-1 disease progression among seroconverters or among HIV-1-positive individuals after adjustment for baseline CD4 count. Maternal CD4 decline and viral load increase in the PHT cohort did not differ between genotypes. Multi-parametric flow cytometry assessment of T cell activation (CD69, HLA-DR, CD38) and Treg frequency (CD25<sup>+</sup>FOXP3<sup>+</sup>) found no differences between genotype groups. Plasma SDF-1α, MIP-1β and TRAIL levels quantified by cytokine bead array were also similar between groups.</p> <p>Conclusions</p> <p>In contrast to previous reports, we were unable to provide evidence to suggest that the <it>GNB3 C825T </it>polymorphism affects HIV-1 acquisition or disease progression within African populations. <it>Ex vivo </it>immune activation and plasma chemokine levels were similarly unaffected by <it>GNB3 </it>genotype in both HIV-1-negative and HIV-1-positive individuals. The paucity of studies investigating the impact of <it>GNB3 </it>polymorphism among African populations and the lack of mechanistic studies make it difficult to assess the true biological significance of this polymorphism in HIV-1 infection.</p
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