49 research outputs found
The Proverbia Catch-22: The Unconstitutionality of Section Five of the Immigration Marriage Fraud Amendments of 1986
Conductive Polymer Pad for Use in Freight Railcar Bearing Adapters
Many freight railcars rest on polymer adapter pads made of injection-molded Thermoplastic Polyurethane (TPU) polymers which feature two copper studs to provide electrical conductivity through the pad. This design feature allows signal transmission from the track to the onboard systems, including cargo gates and pneumatic actuators. While in service, the polymer pads experience impact and cyclic loading that produce shear, resulting in the abrasive wear and plastic compression of the copper studs which leads to signal interruptions and loss of function requiring the periodic replacement of these polymer pads. This causes increased downtime due to maintenance and reduced reliability in the automated systems since pad failure is unpredictable. This limitation in current designs is the driving concern behind the effort to create an electrically conductive polymer adapter pad that would provide a durable conductive path between the rail and freight car side-frame.
To that end, the University Transportation Center for Railway Safety (UTCRS) has been working on developing a conductive composite blend of TPU and Carbon Nano Fibers (CNF) to create injection-molded polymer composite inserts that can provide the necessary conductivity without the need for the copper studs that are susceptible to wear. Previous work done on this project was successful in creating a TPU-CNF composite insert that provided the required electrical conductivity at full railcar loads but was inconsistent at empty railcar loads. Thus, current work presented here focused on studying the fiber orientation that would produce consistent conductivity at all railcar loads. Based on these findings, a new mold was fabricated to create injection-molded polymer composite inserts with the effective fiber orientation. Laboratory test results show that the newly created composite inserts provide approximately double the needed conductivity required for a 24-Volt railcar valve to actuate when tested under the minimum load conditions an adapter would experience in field service. This paper summarizes the work done on fiber alignment and the results of the testing performed on the UTCRS dynamic bearing test rigs
A search for technosignatures from 14 planetary systems in the Kepler field with the Green Bank Telescope at 1.15-1.73 GHz
Analysis of Kepler mission data suggests that the Milky Way includes billions
of Earth-like planets in the habitable zone of their host star. Current
technology enables the detection of technosignatures emitted from a large
fraction of the Galaxy. We describe a search for technosignatures that is
sensitive to Arecibo-class transmitters located within ~420 ly of Earth and
transmitters that are 1000 times more effective than Arecibo within ~13 000 ly
of Earth. Our observations focused on 14 planetary systems in the Kepler field
and used the L-band receiver (1.15-1.73 GHz) of the 100 m diameter Green Bank
Telescope. Each source was observed for a total integration time of 5 minutes.
We obtained power spectra at a frequency resolution of 3 Hz and examined
narrowband signals with Doppler drift rates between +/-9 Hz/s. We flagged any
detection with a signal-to-noise ratio in excess of 10 as a candidate signal
and identified approximately 850 000 candidates. Most (99%) of these candidate
signals were automatically classified as human-generated radio-frequency
interference (RFI). A large fraction (>99%) of the remaining candidate signals
were also flagged as anthropogenic RFI because they have frequencies that
overlap those used by global navigation satellite systems, satellite downlinks,
or other interferers detected in heavily polluted regions of the spectrum. All
19 remaining candidate signals were scrutinized and none were attributable to
an extraterrestrial source.Comment: 15 pages, 5 figures, accepted for publication in the Astronomical
Journa
Produced water: Rare-earth element recovery and clean water production
The team is to research, evaluate, and design an energy efficient treatment system to produce clean water while optimizing the collection of rare earth elements from produced water recovered from oil and gas operations. From the produced water, your process should achieve high recovery of the rare earth elements (minimum 70%) and deliver clean water that meets drinking water standards (500 mg/L) concentration of total dissolved solids). The goals of the designed system are to develop a treatment system that is practical, cost effective, and able to accommodate flow rates of 2000 gallons per day in the full-scale model
Polymethoxyflavones from Nicotiana plumbaginifolia (Solanaceae) exert antinociceptive and neuropharmacological effects in mice.
Polymethoxylavones (PMFs)are known to exhibit significant anti-inflammatory and neuroprotective properties. Nicotiana plumbaginifolia, an annual Bangladeshi herb, is rich in polymethoxyflavones that possess significant analgesic and anxiolytic activities. The present study aimed to determine the antinociceptive and neuropharmacological activities of polyoxygenated flavonoids namely- 3,3',5,6,7,8-hexamethoxy-4',5'-methylenedioxyflavone (1), 3,3',4',5',5,6,7,8-octamethoxyflavone (exoticin) (2), 6,7,4',5'-dimethylenedioxy-3,5,3'-trimethoxyflavone (3) and 3,3’,4’,5,5’,8-hexamethoxy-6,7-methylenedioxyflavone(4), isolated and identified from N. plumbaginifolia. Antinociceptive activity was assessed using the acetic-acid induced writhing, hot plate, tail immersion, formalin and carrageenan-induced paw edema tests, whereas neuropharmacological effects were evaluated in the hole cross, open field and elevated plus maze test. Oral treatment of compounds 1, 3 and 4 (12.5-25 mg/kg b.w.) exhibited dose-dependent and significant (p< 0.01) antinociceptive activity in the acetic-acid, formalin, carrageenan and thermal (hot plate)-induced pain models. The association of ATP-sensitive K+ channel and opioid systems in their antinociceptive effect was obvious from the antagonist effect of glibenclamide and naloxone respectively. These findings suggested central and peripheral antinociceptive activities of the compounds. Compound 1, 3 and 4 (12.5 mg/kg b.w.) demonstrated significant (p< 0.05) anxiolytic-like activity in the elevated plus-maze test, while the involvement of GABAA receptor in the action of compound 3 and 4 was evident from the reversal effects of flumazenil. In addition, compounds 1 and 4 (12.5-25 mg/kg b.w) exhibited anxiolytic activity without altering the locomotor responses. The present study suggested that the polymethoxyflavones (1-4) from N. Plumbaginifoliacould be considered as suitable candidates for the development of analgesic and anxiolytic agents
ABCA7 p.G215S as potential protective factor for Alzheimer’s disease
Genome-wide association studies (GWASs) have been effective approaches to dissect common genetic variability underlying complex diseases in a systematic and unbiased way. Recently, GWASs have led to the discovery of over 20 susceptibility loci for Alzheimer’s disease (AD).
Despite the evidence showing the contribution of these loci to AD pathogenesis, their genetic architecture has not been extensively investigated, leaving the possibility that low frequency and rare coding variants may also occur and contribute to the risk of disease. We have used exome and genome sequencing data to analyse the single independent and joint effect of rare and low frequency protein coding variants in 9 AD GWAS loci with the strongest effect sizes after APOE (BIN1, CLU, CR1, PICALM, MS4A6A, ABCA7, EPHA1, CD33, CD2AP) in a cohort of 332 sporadic AD cases and 676 elderly controls of British and North American ancestry. We identified coding variability in ABCA7 as contributing to AD risk. This locus harbors a low frequency coding variant (p.G215S, rs72973581, MAF=4.3%) conferring a modest but statistically significant protection against AD (p-value= 6x10-4, OR=0.57, 95% CI 0.41-0.80). Notably, our results are not driven by an enrichment of loss of function variants in ABCA7, recently reported as main pathogenic factor underlying AD risk at this locus. In summary, our study confirms the role of ABCA7 in AD and provide new insights that should address functional studies
Perceptions About Work/Life Balance Among DU Community Members with Young Children
Background: In the past fifty years, families in the USA have changed in configuration, size and dynamics. The percentage of families that do not conform to the traditional family unit (married mother and father with children) has increased as there are more single-parent families, LGBTQ families and interracial families. The proportion of unmarried or divorced families has also increased, as it has the number of married and unmarried couples that opt to not have children and, additionally, more couples are opting for adoption and foster parenting (Pew Research Center 2010). Furthermore, the percentage of households where all the adults work has increased, which impacts the amount and quality of time available for family activities and household chores (Bianchi, Robinson and Milkie 2006). These and other trends have led to the identification of “work-family balance” as an important challenge of our times, one that families have been facing for decades and that institutions are only starting to pay attention to (Hochschild 2013). Although there are many aspects of family life that are challenging to balance with workplace demands, childcare has been specifically identified as one that needs attention (Desilver 2014).
Methods: Study goal: To describe the perceptions that some DU community members with children have about work-family balance with attention to challenges, difficulties and institutional responses. Study design: Descriptive, cross-sectional, qualitative study. Population and sample: We recruited 63 University of Denver students (13), staff (14) and faculty (36) who are responsible of parenting at least one child under 10 years of age. We used purposive sampling. which consists in actively finding individuals who meet the criteria. Data collection: Semi structured interviews (January 23-February 8, 2017), in person, audio recorded and transcribed within one week. Participants’ autonomy, confidentiality and anonymity were protected throughout the process. Data analysis: Thematic analysis, which consists in the systematic identification of themes in the interview transcripts, followed by their conceptual organization and hierarchization. Research team: sixty-six undergraduate students taking Cultural Anthropology (ANTH 2010) in winter 2017, four graduate teaching assistants and one course instructor.
Findings: Student participants portrayed work/life balance as set of interconnected situations and relations that go from the deeply personal to the interpersonal, communal and institutional. Aiming at capturing such complexity, we organized our findings in four themes: work/life balance, family dynamics, personal challenges and support. Participants told us about their struggles when negotiating work and life responsibilities which often lead to feelings of guilt, which are mediated by their colleagues’ reactions, schedule flexibility, their job situation and the presence or absence of maternity leave. Family dynamics reflected a tension between a narrative of independence and one of dependence in raising children, highlighting the importance of social networks, both of which are also affected by immigration status and intra-household negotiations particularly, Perceptions about work/life balance among DU community members with young children Cultural Anthropology (ANTH 2010) winter 2017 4 with their partners. Personal challenges relate primarily with time management and establishing clear boundaries between work and family, which related to managing emails, organization and scheduling of activities, maintaining a financial balance, and solving transportation needs, all of which were mediated the ability parents have of controlling a flexible work schedule, an ability greatly diminished among students. Support parents need related to child care goes from the one that happens in interpersonal interactions with neighbors, friends, relatives and colleagues, to the institutionalized forms of support, where participants expressed their frustration for the insufficiency of accessible options in Denver, the lack of options at DU, and the inaccessibility of DU’s Fisher Early Learning Center.
Conclusions and recommendations: Participant’s ability to control their schedules together with their financial and social capital seem to shape important differences in the ability that parents have for balancing work and life. Students, single parents and recent immigrants seem to have a combination of elements that add to the challenges. At the interpersonal level, simple acts of kindness, sympathy and empathy in the everyday interactions seem to make an important difference to parents. The perception that many of the student participants expressed about the academy not being comfortable with children, families or parents could be addressed by making it normal to talk about all these aspects of life. At the institutional level, efforts could be made at reaching out to parents, especially students and single parents, to offer them guidance and support that is already in place at DU, such as counselling and wellbeing resources, as well as orientation related to institutional policies. Policies related to maternity and paternity leave should be refined to ensure that they do not negatively affect those they are supposed to support. Convenient, affordable and sustainable on-campus child care options should be seriously considered given that they would enhance the possibilities for parents to participate in activities at DU. Events should be organized where members of the DU community have the opportunity to share not as students, staff or faculty, but as members of families
Pervasive gaps in Amazonian ecological research
Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4
While the increasing availability of global databases on ecological communities has advanced our knowledge
of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In
the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of
Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus
crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced
environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian
Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by
2050. This means that unless we take immediate action, we will not be able to establish their current status,
much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio
Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world
Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic.
Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality.
Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States.
Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis.
Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection