2,910 research outputs found
The induction motor
Citation: Matthews, Howard David and Dial, Thomas E. The induction motor. Senior thesis, Kansas State Agricultural College, 1904.Morse Department of Special CollectionsIntroduction:The induction motor is a type of alternating current motor in which the magnetic flux is furnished by either a single phase or a polyphase current. Consider the action of a compass suspended over a magnetic field, the needle thus suspended will take a position parallell to the lines of force, which flow from pole to pole. Now if the nagnet be rotated the needle will change position relative to it. If the magnet be substituted for a four pole electro-magnet as shown in Fig. 1 Plate 1 and a current of electricity be allowed to flow about either of the sets of poles, and the needle be allowed to swing freely in the center, it will set its self parallel to the lines if a current is flowing in all four poles at the same time this needle will set itself diagonally half way between the sets of poles, as illustrated by Fig. 2. Plate 1. It is now easily conceivable that, if one of these currents, in the windings of the poles is becoming weaker as the other is growing stronger, t the needle will be attracted to the former until the flux reaches its maximum value. Where an alternating current is used this process of rapidly changing from maximum to minimum tends to rotate the needle. If,now, a cylinder consisting of copper conductors be used, instead of a needle, the machine becomes an Induction Motor. The direction of rotation is determined by the phase relation of the currents, The direction of rotation may be reversed by interchanging and two wires of a three phase three wire circuit. Thus by means of polyphase currents it is very easy to produce rotating fields
Publication Integration at Purdue: A Comprehensive Publication Workflow for Traditional Publications and Data Publications
Many funders around the world have begun to recognize the importance of providing free access to research results, which includes publications and data. There has also been an increased interest in the management, dissemination, and access of research data, leading to an increase in the development of research data repositories and the linkage of data to publications. One example is Dryad, a curated general-purpose repository that makes the data underlying scientific publications discoverable, freely reusable, and citable. A highlight of the Dryad repository is the submission integration service to authors and publishers, which integrates the submission of publication manuscripts with the submission of data to Dryad. Purdue University has developed a comprehensive publication workflow to integrate discrete data publications with traditional scholarly publications through leveraging new and existing repository platforms and library services throughout the research lifecycle. This poster will illustrate this early initiative between the Purdue e-Pubs Repository, the Purdue University Research Repository (PURR), and the Joint Transportation Research Program (JTRP). With this new initiative the Purdue repositories can now provide Purdue faculty, graduate students, and staff an integrated solution for the publishing and linkage of discrete scholarly publications and research data
Static Socio-Ecological COVID-19 Vulnerability Index and Vaccine Hesitancy Index for England
Background: Population characteristics can be used to infer vulnerability of communities to COVID-19, or to the likelihood of high levels of vaccine hesitancy. Communities harder hit by the virus, or at risk of being so, stand to benefit from greater resource allocation than their population size alone would suggest. This study reports a simple but efficacious method of ranking small areas of England by relative characteristics that are linked with COVID-19 vulnerability and vaccine hesitancy. Methods: Publicly available data on a range of characteristics previously linked with either poor COVID-19 outcomes or vaccine hesitancy were collated for all Middle Super Output Areas of England (MSOA, n=6790, excluding Isles of Scilly), scaled and combined into two numeric indices. Multivariable linear regression was used to build a parsimonious model of vulnerability (static socio-ecological vulnerability index, SEVI) in 60% of MSOAs, and retained variables were used to construct two simple indices. Assuming a monotonic relationship between indices and outcomes, Spearman correlation coefficients were calculated between the SEVI and cumulative COVID-19 case rates at MSOA level in the remaining 40% of MSOAs over periods both during and out with national lockdowns. Similarly, a novel vaccine hesitancy index (VHI) was constructed using population characteristics aligned with factors identified by an Office for National Statistics (ONS) survey analysis. The relationship between the VHI and vaccine coverage in people aged 12+years (as of 2021-06-24) was determined using Spearman correlation. The indices were split into quintiles, and MSOAs within the highest vulnerability and vaccine hesitancy quintiles were mapped. Findings: The SEVI showed a moderate to strong relationship with case rates in the validation dataset across the whole study period, and for every intervening period studied except early in the pandemic when testing was highly selective. The SEVI was more strongly correlated with case rates than any of its domains (rs 0·59 95% CI 0.57-0.62) and outperformed an existing MSOA-level vulnerability index. The VHI was significantly negatively correlated with COVID-19 vaccine coverage in the validation data at the time of writing (rs -0·43 95% CI -0·46 to -0·41). London had the largest number and proportion of MSOAs in quintile 5 (most vulnerable/hesitant) of SEVI and VHI concurrently. Interpretation: The indices presented offer an efficacious way of identifying geographical disparities in COVID-19 risk, thus helping focus resources according to need. Funding: Funder: Integrated Covid Hub North East Award number: n/a Grant recipient: Fiona Matthew
The Economic Value of Water: Results of a Workshop in Caracas, Venezuela, November 2000
In November 2000 a small workshop of 14 people met in Caracas, Venezuela, to discuss the value\u27 of water. The meeting was sponsored by the International Water Resources Network (IWRN), the Organization of American States (OAS), The Nature Conservancy, the University of New Mexico, and the National Oceanic and Atmospheric Administration (NOAA). The meeting was hosted by Jose Ochoa-Iturbe, Director of the School of Civil Engineering at the Universidad Catolica Andres Bello. The participants represented a mix of academics, water administrators, government officials and NGOs (non-governmental organizations) from around the Americas. Although many of the participants are economists, multiple disciplines and perspectives were represented. The meeting occurred as part of a process for stimulating discussion about water issues in the Americas. During and after IWRN\u27s Dialog III in Panama, the participants at a session on water valuation discussed the need for an intermediate meeting that would keep the discussion moving forward. The feeling was that the time interval between Dialogs was too long and significant time was spent at each Dialog repeating conversations that had occurred before. An intermediate conference was organized in Caracas to fill that need. This document was produced as a result of the Caracas meeting and is meant to serve as an input to IWRN\u27s Dialog IV in Brazil. The document should not be looked on as the final word but as an intermediate step meant to stimulate additional discussion
Public perceptions of drinking water: A postal survey of residents with private water supplies
Background: In Canada, the legal responsibility for the condition of private water supplies,
including private wells and cisterns, rests with their owners. However, there are reports that
Canadians test these water supplies intermittently and that treatment of such water is uncommon.
An estimated 45% of all waterborne outbreaks in Canada involve non-municipal systems. An
understanding of the perceptions and needs of Canadians served by private water supplies is
essential, as it would enable public health professionals to better target public education and
drinking water policy. The purpose of this study was to investigate the public perceptions of private
water supplies in the City of Hamilton, Ontario (Canada), with the intent of informing public
education and outreach strategies within the population.
Methods: A cross-sectional postal survey of 246 residences with private water supplies was
conducted in May 2004. Questions pertained to the perceptions of water quality and alternative
water sources, water testing behaviours and the self-identified need for further information.
Results: Private wells, cisterns or both, were the source of household water for 71%, 16% and
13% of respondents, respectively. Although respondents rated their water quality highly, 80% also
had concerns with its safety. The most common concerns pertained to bacterial and chemical
contamination of their water supply and its potential negative effect on health. Approximately 56%
and 61% of respondents used in-home treatment devices and bottled water within their homes,
respectively, mainly due to perceived improvements in the safety and aesthetic qualities compared
to regular tap water. Testing of private water supplies was performed infrequently: 8% of
respondents tested at a frequency that meets current provincial guidelines. Two-thirds of
respondents wanted more information on various topics related to private water supplies. Flyers
and newspapers were the two media reported most likely to be used.
Conclusion: Although respondents rated their water quality highly, the majority had concerns
regarding the water from their private supply, and the use of bottled water and water treatment
devices was extensive. The results of this study suggest important lines of inquiry and provide
support and input for public education programs, particularly those related to private water testing,
in this population
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Origins of chromosomal rearrangement hotspots in the human genome: evidence from the AZFa deletion hotspots.
RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are.BACKGROUND: The origins of the recombination hotspots that are a common feature of both allelic and non-allelic homologous recombination in the human genome are poorly understood. We have investigated, by comparative sequencing, the evolution of two hotspots of non-allelic homologous recombination on the Y chromosome that lie within paralogous sequences known to sponsor deletions resulting in male infertility. RESULTS: These recombination hotspots are characterized by signatures of concerted evolution, which indicate that gene conversion between paralogs has been predominant in shaping their recent evolution. By contrast, the paralogous sequences that surround the hotspots exhibit little evidence of gene conversion. A second feature of these rearrangement hotspots is the extreme interspecific sequence divergence (around 2.5%) that places them among the most divergent orthologous sequences between humans and chimpanzees. CONCLUSIONS: Several hominid-specific gene conversion events have rendered these hotspots better substrates for chromosomal rearrangements in humans than in chimpanzees or gorillas. Monte Carlo simulations of sequence evolution suggest that extreme sequence divergence is a direct consequence of gene conversion between paralogs. We propose that the coincidence of signatures of concerted evolution and recurrent breakpoints of chromosomal rearrangement (mapped at the sequence level) may enable the identification of putative rearrangement hotspots from analysis of comparative sequences from great apes
Can vaccination roll-out be more equitable if population risk is taken into account?
Background COVID-19 vaccination in many countries, including England, has been prioritised primarily by age. However, people of the same age can have very different health statuses. Frailty is a commonly used metric of health and has been found to be more strongly associated with mortality than age among COVID-19 inpatients. Methods We compared the number of first vaccine doses administered across the 135 NHS Clinical Commissioning Groups (CCGs) of England to both the over 50 population and the estimated frail population in each area. Area-based frailty estimates were generated using the English Longitudinal Survey of Ageing (ELSA), a national survey of older people. We also compared the number of doses to the number of people with other risk factors associated with COVID- 19: Atrial fibrillation, chronic kidney disease, diabetes, learning disabilities, obesity and smoking status. Results We estimate that after 79 days of the vaccine program, across all Clinical Commissioning Group areas, the number of people who received a first vaccine per frail person ranged from 4.4 (95% CI 4.0-4.8) and 20.1 (95% CI 18.3-21.9). The prevalences of other risk factors were also poorly associated with the prevalence of vaccination across England. Conclusions Vaccination with age-based priority created area-based inequities in the number of doses administered relative to the number of people who are frail or have other risk factors associated with COVID-19. As frailty has previously been found to be more strongly associated with mortality than age for COVID-19 inpatients, an age-based priority system may increase the risk of mortality in some areas during the vaccine roll-out period. Authorities planning COVID-19 vaccination programmes should consider the disadvantages of an age-based priority system
The small RNA locus map for Chlamydomonas reinhardtii.
Small (s)RNAs play crucial roles in the regulation of gene expression and genome stability across eukaryotes where they direct epigenetic modifications, post-transcriptional gene silencing, and defense against both endogenous and exogenous viruses. It is known that Chlamydomonas reinhardtii, a well-studied unicellular green algae species, possesses sRNA-based mechanisms that are distinct from those of land plants. However, definition of sRNA loci and further systematic classification is not yet available for this or any other algae. Here, using data-driven machine learning approaches including Multiple Correspondence Analysis (MCA) and clustering, we have generated a comprehensively annotated and classified sRNA locus map for C. reinhardtii. This map shows some common characteristics with higher plants and animals, but it also reveals distinct features. These results are consistent with the idea that there was diversification in sRNA mechanisms after the evolutionary divergence of algae from higher plant lineages
IP Tunneling and Stateless DHCPv6 Implementation in an Enterprise Network
IPv4 has so many limitations such as limited assignable
addresses, complex subnetting structure, and inefficient
employment of NAT among others. It is because of these
shortcomings of IPv4 that IPv6 protocol was introduced.
IPv6 increases efficiency in routing and packet
processing, promotes a simplified network
configuration, supports new services and adds to the
improvement QoS by reducing latency during packet
transfer. There is therefore a need to move to the IPv6
platform. However, such a process is not automatic but
deliberate and requires dealing with the current
complexities of the IPv4 network. Tunneling is one of
the common ways of transiting from IPv4 to IPv6 and
vice versa. In this paper we simulated an IPv6to4 tunnel
using cisco packet tracer and GNS software. It was
shown that tunneling is a possibility and an effective
step to preserving IPv4 infrastructure investments
towards migrating from IPv4 to IPv6
Exposure to secondhand smoke and cognitive impairment in non-smokers: national cross sectional study with cotinine measurement
Objective To examine the association between a biomarker of exposure to secondhand smoke (salivary cotinine concentration) and cognitive impairment
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