637 research outputs found
Construction of Digital Elevation Models for Archaeological Applications
The use of interpolation in archaeology is becoming common. As archaeologists incorporate geographic information systems (GIS) and computer mapping programs into their research, questions of interpolation become fundamental considerations in the representation and manipulation of topographic data. To date, however, few archaeologists have dealt with these questions. Uncritical use of interpolation algorithms can result in unrealistic representations of the landscape in a mapping program or can result in an inaccurate digital elevation model (DEM) used in a GIS. This, in turn, can lead to an ineffective predictive model of site location. By carefully selecting an interpolation algorithm that is well suited to the data, statistical pitfalls and wasted effort can be avoided
Mars promotes dTACC dephosphorylation on mitotic spindles to ensure spindle stability
Microtubule-associated proteins (MAPs) ensure the fidelity of chromosome segregation by controlling microtubule (MT) dynamics and mitotic spindle stability. However, many aspects of MAP function and regulation are poorly understood in a developmental context. We show that mars, which encodes a Drosophila melanogaster member of the hepatoma up-regulated protein family of MAPs, is essential for MT stabilization during early embryogenesis. As well as associating with spindle MTs in vivo, Mars binds directly to protein phosphatase 1 (PP1) and coimmunoprecipitates from embryo extracts with minispindles and Drosophila transforming acidic coiled-coil (dTACC), two MAPs that function as spindle assembly factors. Disruption of binding to PP1 or loss of mars function results in elevated levels of phosphorylated dTACC on spindles. A nonphosphorylatable form of dTACC is capable of rescuing the lethality of mars mutants. We propose that Mars mediates spatially controlled dephosphorylation of dTACC, which is critical for spindle stabilization
Journalists at risk: News media perspectives
On 22 May 2009, Massey University’s Wellington campus hosted many speakers addressing the conference on war reporting jointly organised by the International Committee of the Red Cross. Media speakers included Television New Zealand’s Sunday programme reporter Cameron Bennett; Radio NZ political editor Brent Edwards; Fairfax NZ reporter Michael Field; Fairfax Media editorial development manager Clive Lind; Pacific Media Centre director and AUT University associate professor Dr David Robie; freelance foreign correspondent Jon Stephenson; and Radio NZ International news editor Walter Zweifel. Commentaries, in some cases transcribed from recordings of proceedings, have been abridged. This transcript was compiled by Massey journalism programme lecturer Alan Samson
An internet survey of 2,596 people with fibromyalgia
BACKGROUND: This study explored the feasibility of using an Internet survey of people with fibromyalgia (FM), with a view to providing information on demographics, sources of information, symptoms, functionality, perceived aggravating factors, perceived triggering events, health care utilization, management strategies, and medication use. METHODS: A survey questionnaire was developed by the National Fibromyalgia Association (NFA) in conjunction with a task force of "experts in the field". The questionnaire underwent several rounds of testing to improve its face validity, content validity, clarity and readability before it was mounted on the internet. The questionnaire consisted of 121 items and is available online at the website of the National Fibromyalgia Association. RESULTS: The questionnaire was completed by 2,569 people. Most were from the United States, with at least one respondent from each of the 50 states. Respondents were predominantly middle-aged Caucasian females, most of whom had FM symptoms for ≥ 4 years. The most common problems were morning stiffness, fatigue, nonrestorative sleep, pain, concentration, and memory. Aggravating factors included: emotional distress, weather changes, insomnia, and strenuous activity. Respondents rated the most effective management modalities as rest, heat, pain medications, antidepressants, and hypnotics. The most commonly used medications were: acetaminophen, ibuprofen, naproxen, cyclobenzaprine, amitriptyline, and aspirin. The medications perceived to be the most effective were: hydrocodone preparations, aprazolam, oxycodone preparations, zolpidem, cyclobenzaprine, and clonazepam. CONCLUSION: This survey provides a snap-shot of FM at the end of 2005, as reported by a self-selected population of people. This descriptive data has a heuristic function, in that it identifies several issues for further research, such as the prescribing habits of FM health care providers, the role of emotional precipitants, the impact of obesity, the significance of low back pain and the nature of FM related stiffness
Delay Jitter Bounds and Packet Scale Rate Guarantee for Expedited Forwarding
We consider the definition of the Expedited Forwarding Per-Hop Behaviour (EF PHB) as given in RFC 2598, and its impact on worst case end-to-end delay jitter. On one hand, the definition in RFC 2598 can be used to predict extremely low end-to-end delay jitter, independent of the network scale. On the other hand, we find that the worst case delay jitter can be made arbitrarily large, while each flow traverses at most a specified number of hops, if we allow networks to become arbitrarily large, this is in contradiction with the previous statement. We analyze where the contradiction originates, and find the explanation. It resides in the fact that the definition in RFC 2598 is not easily implementable in schedulers we know of, mainly because it is not formal enough, and also because it does not contain an error term. We propose a new definition for the EF PHB, called ``Packet Scale Rate Guarante
Argon Abundances in the Solar Neighborhood: Non-LTE Analysis of Orion Association B-type Stars
Argon abundances have been derived for a sample of B main-sequence stars in
the Orion association. The abundance calculations are based on NLTE metal
line-blanketed model atmospheres calculated with the NLTE code TLUSTY and an
updated and complete argon model atom. We derive an average argon abundance for
this young population of A(Ar) = 6.66 +- 0.06. While our result is in excellent
agreement with a recent analysis of the Orion nebula, it is significantly
higher than the currently recommended solar value which is based on abundance
measurements in the solar corona. Moreover, the derived argon abundances in the
Orion B stars agree very well with a measurement from a solar impulsive flare
during which unmodified solar photospheric material was brought to flare
conditions. We therefore argue that the argon abundances obtained independently
for both the Orion B stars and the Orion nebula are representative of the disk
abundance value in the solar neighborhood. The lower coronal abundance may
reflect a depletion related to the FIP effect. We propose a new reference value
for the abundance of argon in the solar neighborhood, A(Ar) = 6.63 +- 0.10,
corresponding to Ar/O = 0.009.Comment: to appear in Astrophysical Journal, 24 pages, 3 figures; minor
corrections after referee's repor
In vivo killing of Staphylococcus aureus using a light-activated antimicrobial agent
Background: The widespread problem of antibiotic resistance in pathogens such as Staphylococcus aureus has prompted the search for new antimicrobial approaches. In this study we report for the first time the use of a light-activated antimicrobial agent, methylene blue, to kill an epidemic methicillin-resistant Staphylococcus aureus (EMRSA-16) strain in two mouse wound models.Results: Following irradiation of wounds with 360 J/cm(2) of laser light (670 nm) in the presence of 100 mu g/ml of methylene blue, a 25-fold reduction in the number of viable EMRSA was seen. This was independent of the increase in temperature of the wounds associated with the treatment. Histological examination of the wounds revealed no difference between the photodynamic therapy (PDT)-treated wounds and the untreated wounds, all of which showed the same degree of inflammatory infiltration at 24 hours.Conclusion: The results of this study demonstrate that PDT is effective at reducing the total number of viable EMRSA in a wound. This approach has promise as a means of treating wound infections caused by antibiotic-resistant microbes as well as for the elimination of such organisms from carriage sites
Effects of low earth orbit on the optical performance of multi-layer enhanced high reflectance mirrors
Two mirror designs developed for space applications were flown along with a standard mid-infrared design on the leading and trailing edges of the Long Duration Exposure Facility (LDEF). Preliminary observations of induced changes in optical performance of ZnS-coated mirrors and impact-related microstructural and microchemical effects are described in the proceedings of the First LDEF Post-Retrieval Symposium. In this paper, effects of the induced environment and meteoroid/debris impacts on mirror performance are described in more detail. Also, an analysis of reflectance spectra using the results of Auger and secondary ion mass spectroscopy (SIMS) profiling measurements are used to identify an optical-degradation mechanism for the ZnS-coated mirrors. Structural damage associated with a high-velocity impact on a (Si/Al2O3)-coated mirror was imaged optically and with scanning electron and atomic force microscopy (SEM and AFM). Scanning Auger and SIMS analysis provided chemical mapping of selected impact sites. The impact data suggest design and fabrication modifications for obtaining improved mechanical performance using a design variation identified in preflight laboratory simulations. Auger surface profile and SIMS imaging data verified the conclusion that secondary impacts are the source of contamination associated with the dendrites grown on the leading-edge ZnS-coated test samples. It was also found that dendrites can be grown in the laboratory by irradiating contaminated sites on a trailing-edge ZnS-coated sample with a rastered electron beam. These results suggest a mechanism for dendrite growth
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