675 research outputs found
Non-volatile, high density, high speed, Micromagnet-Hall effect Random Access Memory (MHRAM)
The micromagnetic Hall effect random access memory (MHRAM) has the potential of replacing ROMs, EPROMs, EEPROMs, and SRAMs because of its ability to achieve non-volatility, radiation hardness, high density, and fast access times, simultaneously. Information is stored magnetically in small magnetic elements (micromagnets), allowing unlimited data retention time, unlimited numbers of rewrite cycles, and inherent radiation hardness and SEU immunity, making the MHRAM suitable for ground based as well as spaceflight applications. The MHRAM device design is not affected by areal property fluctuations in the micromagnet, so high operating margins and high yield can be achieved in large scale integrated circuit (IC) fabrication. The MHRAM has short access times (less than 100 nsec). Write access time is short because on-chip transistors are used to gate current quickly, and magnetization reversal in the micromagnet can occur in a matter of a few nanoseconds. Read access time is short because the high electron mobility sensor (InAs or InSb) produces a large signal voltage in response to the fringing magnetic field from the micromagnet. High storage density is achieved since a unit cell consists only of two transistors and one micromagnet Hall effect element. By comparison, a DRAM unit cell has one transistor and one capacitor, and a SRAM unit cell has six transistors
A learning community approach to identifying interventions in health systems to reduce colorectal cancer screening disparities.
Although colorectal cancer (CRC) screening in the United States has been increasing, screening rates are not optimal, and there are persistent disparities in CRC screening and mortality, particularly among minority patients. As most CRC screening takes place in primary care, health systems are well-positioned to address this important population health problem. However, most health systems have not actively engaged in identifying and implementing effective evidence-based intervention strategies that can raise CRC screening rates and reduce disparities. Drawing on the Collective Impact Model and the Interactive Systems Framework for Dissemination and Implementation, our project team applied a learning community strategy to help two health systems in southeastern Pennsylvania identify evidence-based CRC screening interventions for primary care patients. Initially, this approach involved activating a coordinating team, steering committee (health system leadership and stakeholder organizations), and patient and stakeholder advisory committee to identify candidate CRC screening intervention strategies. The coordinating team guided the steering committee through a scoping review to identify seven randomized trials that identified interventions that addressed CRC screening disparities. Subsequently, the coordinating team and steering committee applied a screening intervention classification typology to select an intervention strategy that involved using an outreach strategy to provide minority patients with access to both stool blood test and colonoscopy screening. Finally, the coordinating team and steering committee engaged the health system patient and stakeholder advisory committee in planning for intervention implementation, thus taking up the challenge of reducing and important health disparity in patient populations served by the two health systems
Radio Jet-Ambient Medium Interactions on Parsec Scales in the Blazar 1055+018
As part of our study of the magnetic fields of AGN we have recently observed
a large sample of blazars with the Very Long Baseline Array. Here we report the
discovery of a striking two-component jet in the source 1055+018, consisting of
an inner spine with a transverse magnetic field, and a fragmentary but distinct
boundary layer with a longitudinal magnetic field. The polarization
distribution in the spine strongly supports shocked-jet models while that in
the boundary layer suggests interaction with the surrounding medium. This
behavior suggests a new way to understand the differing polarization properties
of strong- and weak-lined blazars.Comment: LaTex; 10 pages; 6 figures; reference fix; to appear in ApJL, 518,
1999 June 2
Do Employees From Less-Healthy Communities Use More Care and Cost More? Seeking to Establish a Business Case for Investment in Community Health.
INTRODUCTION: Few studies have examined the impact of community health on employers. We explored whether employed adults and their adult dependents living in less-healthy communities in the greater Philadelphia region used more care and incurred higher costs to employers than employees from healthier communities.
METHODS: We used a multi-employer database to identify adult employees and dependents with continuous employment and mapped them to 31 zip code regions. We calculated community health scores at the regional level, by using metrics similar to the Robert Wood Johnson Foundation (RWJF) County Health Rankings but with local data. We used descriptive analyses and multilevel linear modeling to explore relationships between community health and 3 outcome variables: emergency department (ED) use, hospital use, and paid claims. Business leaders reviewed findings and offered insights on preparedness to invest in community health improvement.
RESULTS: Poorer community health was associated with high use of ED services, after controlling for age and sex. After including a summary measure of racial composition at the zip code region level, the relationship between community health and ED use became nonsignificant. No significant relationships between community health and hospitalizations or paid claims were identified. Business leaders expressed interest in further understanding health needs of communities where their employees live.
CONCLUSION: The health of communities in which adult employees and dependents live was associated with ED use, but similar relationships were not seen for hospitalizations or paid claims. This finding suggests a need for more primary care access. Despite limited quantitative evidence, business leaders expressed interest in guidance on investing in community health improvement
Informal traders lock horns with the formal milk industry: the role of research in pro-poor dairy policy shift in Kenya
Sensitive VLBI Continuum and H I Absorption Observations of NGC 7674: First Scientific Observations with the Combined Array VLBA, VLA & Arecibo
We present phase-referenced VLBI observations of the radio continuum emission
from, and the H I 21 cm absorption toward, the Luminous Infrared Galaxy NGC
7674. The observations were carried out at 1380 MHz using the VLBA, the phased
VLA, and theArecibo radio telescope. These observations constitute the first
scientific use of the Arecibo telescope in a VLBI observation with the VLBA.
The high- and low-resolution radio continuum images reveal several new
continuum structures in the nuclear region of this galaxy. At ~100 mas
resolution, we distinguish six continuum structures extending over 1.4 arcsec,
with a total flux density of 138 mJy. Only three of these structures were known
previously. All these structures seem to be related to AGN activity. At the
full resolution of the array, we only detect two of the six continuum
structures. Both are composed of several compact components with brightness
temperatures on the order of K. While it is possible that one of these
compact structures could host an AGN, they could also be shock-like features
formed by the interaction of the jet with compact interstellar clouds in the
nuclear region of this galaxy. Complex H I absorption is detected with our VLBI
array at both high and low angular resolution. Assuming that the widest H I
feature is associated with a rotating H I disk or torus feeding a central AGN,
we estimate an enclosed dynamical mass of ~7 x 10^7 M_sun, comparable to the
value derived from the hidden broad H emission in this galaxy. The
narrower H I lines could represent clumpy neutral hydrogen structures in the H
I torus. The detection of H I absorption toward some of the continuum
components, and its absence toward others, suggest an inclined H I disk or
torus in the central region of NGC 7674.Comment: 37 pages, 11 figures. ApJ accepted. To appear in the Nov. 10, 2003
issue of ApJ. Please use the PDF version if the postscript doesn't show the
figure
Nutrient flows and balances in intensive crop-dairy production systems in the Kenya highlands
Sustainability of their agricultural systems is essential for many tropical countries where the majority of the people depend upon agriculture for their livelihoods. In the short term economic sustainability is the main factor influencing viability of an agricultural system and of the farms which form its production units. In the long-term, however, economic viability will depend upon the nutrient status of a system. In common with much of the eastern African highlands, Kiambu district in central Kenya has high and increasing pressure on its land and farmers are responding by steadily intensifying their farming systems. This paper addresses the hypothesis that where ruminant livestock are present in intensifying smallholder cropping systems, they make a positive contribution to the nutrient status of the smallholder system.
For 21 crop-dairy farms representative of the major smallholder-farming systems in the central highlands of Kenya, annual nutrient balances were determined in a longitudinal study. The farms were visited twice a week; data on all farm inputs and outputs were collected, based on farmer recall. Measures of livestock feed inputs were collected fortnightly. Estimates of nutrient gains and losses in the soil resulting from erosion, leaching, denitrification, volatilisation and N fixation were taken from the literature. Using these data, annual nutrient balances per hectare were estimated for N, P and K.
The majority of the sample farms had balanced nutrient flows or were in positive balance for N, P and K overall because of positive flows to the dairy sub-unit, which counterbalanced the outflows from the crop sub-unit. The dairy unit contributed significantly, principally through feed purchases, particularly concentrates for lactating cows. Napier grass and crop residues were also purchased, and large quantities of roadside grass were collected from outside the farms. On the majority of the farms the nutrients returned to the cropping land as manure (which consisted of faeces, bedding material and feed refusals) contributed more nutrients than inorganic fertilisers.
It is concluded that the dairy cattle played a major role in contributing nutrient in-flows into these intensive smallholder farms, as well as providing the household’s regular source of income through milk sales
DiFX2: A more flexible, efficient, robust and powerful software correlator
Software correlation, where a correlation algorithm written in a high-level
language such as C++ is run on commodity computer hardware, has become
increasingly attractive for small to medium sized and/or bandwidth constrained
radio interferometers. In particular, many long baseline arrays (which
typically have fewer than 20 elements and are restricted in observing bandwidth
by costly recording hardware and media) have utilized software correlators for
rapid, cost-effective correlator upgrades to allow compatibility with new,
wider bandwidth recording systems and improve correlator flexibility. The DiFX
correlator, made publicly available in 2007, has been a popular choice in such
upgrades and is now used for production correlation by a number of
observatories and research groups worldwide. Here we describe the evolution in
the capabilities of the DiFX correlator over the past three years, including a
number of new capabilities, substantial performance improvements, and a large
amount of supporting infrastructure to ease use of the code. New capabilities
include the ability to correlate a large number of phase centers in a single
correlation pass, the extraction of phase calibration tones, correlation of
disparate but overlapping sub-bands, the production of rapidly sampled
filterbank and kurtosis data at minimal cost, and many more. The latest version
of the code is at least 15% faster than the original, and in certain situations
many times this value. Finally, we also present detailed test results
validating the correctness of the new code.Comment: 28 pages, 9 figures, accepted for publication in PAS
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Linking International Agricultural Research Knowledge with Action for Sustainable Development
We applied an innovation framework to sustainable livestock development research projects in Africa and Asia. The focus of these projects ranged from pastoral systems to poverty and ecosystems services mapping to market access by the poor to fodder and natural resource management to livestock parasite drug resistance. We found that these projects closed gaps between knowledge and action by combining different kinds of knowledge, learning, and boundary spanning approaches; by providing all partners with the same opportunities; and by building the capacity of all partners to innovate and communicate
Come to Daddy? Claiming Chris Cunningham for British Art Cinema
Twenty years after he came to prominence via a series of provocative, ground-breaking music videos, Chris Cunningham remains a troubling, elusive figure within British visual culture. His output – which includes short films, advertisements, art gallery commissions, installations, music production and a touring multi-screen live performance – is relatively slim, and his seemingly slow work rate (and tendency to leave projects uncompleted or unreleased) has been a frustration for fans and commentators, particularly those who hoped he would channel his interests and talents into a full-length ‘feature’ film project. There has been a diverse critical response to his musical sensitivity, his associations with UK electronica culture – and the Warp label in particular – his working relationship with Aphex Twin, his importance within the history of the pop video and his deployment of transgressive, suggestive imagery involving mutated, traumatised or robotic bodies. However, this article makes a claim for placing Cunningham within discourses of British art cinema. It proposes that the many contradictions that define and animate Cunningham's work – narrative versus abstraction, political engagement versus surrealism, sincerity versus provocation, commerce versus experimentation, art versus craft, a ‘British’ sensibility versus a transnational one – are also those that typify a particular terrain of British film culture that falls awkwardly between populism and experimentalism
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