397 research outputs found
Addendum: "The Dynamics of M15: Observations of the Velocity Dispersion Profile and Fokker-Planck Models" (ApJ, 481, 267 [1997])
It has recently come to our attention that there are axis scale errors in
three of the figures of Dull et al. (1997, hereafter D97). D97 presented
Fokker-Planck models for the collapsed-core globular cluster M15 that include a
dense, centrally concentrated population of neutron stars and massive white
dwarfs, but do not include a central black hole. In this Addendum, we present
corrected versions of Figures 9, 10, and 12, and an expanded version of Figure
6. This latter figure, which shows the full run of the velocity dispersion
profile, indicates that the D97 model predictions are in good agreement with
the moderately rising HST-STIS velocity dispersion profile for M15 reported by
Gerssen et al. (2002, astro-ph/0209315). Thus, a central black hole is not
required to fit the new STIS velocity measurements, provided that there is a
sufficient population of neutron stars and massive white dwarfs. This
conclusion is consistent with the findings of Gerssen et al. (2002,
astro-ph/0210158), based on a reapplication of their Jeans equation analysis
using the corrected mass-to-light profile (Figure 12) for the D97 models.Comment: 4 pages, 4 figures, submitted to Ap
Transgenic expression of human glial cell line-derived neurotrophic factor (hGDNF) from integration-deficient lentiviral vectors is neuroprotective in a rodent model of Parkinson's disease
Standard integration-proficient lentiviral vectors (IPLVs) are effective at much lower doses than other vector systems and have shown promise for gene therapy of Parkinson's disease (PD). Their main drawback is the risk of insertional mutagenesis. The novel biosafety-enhanced integration-deficient lentiviral vectors (IDLVs) may offer a significant enhancement in biosafety, but have not been previously tested in a model of a major disease. We have assessed biosafety and transduction efficiency of IDLVs in a rat model of PD, using IPLVs as a reference. Genomic insertion of lentivectors injected into the lesioned striatum was studied by linear amplification-mediated polymerase chain reaction (PCR), followed by deep sequencing and insertion site analysis, demonstrating lack of significant IDLV integration. Reporter gene expression studies showed efficient, long-lived, and transcriptionally targeted expression from IDLVs injected ahead of lesioning in the rat striatum, although at somewhat lower expression levels than from IPLVs. Transgenic human glial cell line-derived neurotrophic factor (hGDNF) expression from IDLVs was used for a long-term investigation of lentivector-mediated, transcriptionally targeted neuroprotection in this PD rat model. Vectors were injected before striatal lesioning, and the results showed improvements in nigral dopaminergic neuron survival and behavioral tests regardless of lentiviral integration proficiency, although they confirmed lower expression levels of hGDNF from IDLVs. These data demonstrate the effectiveness of IDLVs in a model of a major disease and indicate that these vectors could provide long-term PD treatment at low dose, combining efficacy and biosafety for targeted central nervous system applications
Construct validity of the Actiwatch-2 for assessing movement in people with profound intellectual and multiple disabilities
Background: Valid measures to assess either small or assisted performed movements of people with profound intellectual and multiple disabilities (PIMD) are required. We analysed the construct validity of the Actiwatch-2 to assess movement in people with PIMD. Method: Twenty-two persons with PIMD were video recorded while wearing an Actiwatch-2. We used 15s-partial-interval recording to record upper body movement, body position and activity situation. Multilevel analyses were used to evaluate if the Actiwatch-2, based on produced counts, could detect changes in these factors. Results: The presence versus absence of upper body movement and an activity situation in which participants were involved versus not involved resulted in significantly higher counts, with a large variety in predicted counts between participants. No relationship between body position and counts was found. Conclusions: The Actiwatch-2 seems able to assess obvious upper body movement in people with PIMD, and whether there is involvement in an activity situation
Immunogenicity and tolerability of recombinant serogroup B meningococcal vaccine administered with or without routine infant vaccinations according to different immunization schedules: a randomized controlled trial..
Measuring gravitational waves from binary black hole coalescences: I. Signal to noise for inspiral, merger, and ringdown
We estimate the expected signal-to-noise ratios (SNRs) from the three phases
(inspiral,merger,ringdown) of coalescing binary black holes (BBHs) for initial
and advanced ground-based interferometers (LIGO/VIRGO) and for space-based
interferometers (LISA). LIGO/VIRGO can do moderate SNR (a few tens), moderate
accuracy studies of BBH coalescences in the mass range of a few to about 2000
solar masses; LISA can do high SNR (of order 10^4) high accuracy studies in the
mass range of about 10^5 to 10^8 solar masses. BBHs might well be the first
sources detected by LIGO/VIRGO: they are visible to much larger distances (up
to 500 Mpc by initial interferometers) than coalescing neutron star binaries
(heretofore regarded as the "bread and butter" workhorse source for LIGO/VIRGO,
visible to about 30 Mpc by initial interferometers). Low-mass BBHs (up to 50
solar masses for initial LIGO interferometers; 100 for advanced; 10^6 for LISA)
are best searched for via their well-understood inspiral waves; higher mass
BBHs must be searched for via their poorly understood merger waves and/or their
well-understood ringdown waves. A matched filtering search for massive BBHs
based on ringdown waves should be capable of finding BBHs in the mass range of
about 100 to 700 solar masses out to 200 Mpc (initial LIGO interferometers),
and 200 to 3000 solar masses out to about z=1 (advanced interferometers). The
required number of templates is of order 6000 or less. Searches based on merger
waves could increase the number of detected massive BBHs by a factor of order
10 or more over those found from inspiral and ringdown waves, without detailed
knowledge of the waveform shapes, using a "noise monitoring" search algorithm.
A full set of merger templates from numerical relativity could further increase
the number of detected BBHs by an additional factor of up to 4.Comment: 40 pages, Revtex, psfig.tex, seven figures, submitted to Phys Rev
Content and Quality of Motor Initiatives in the Support of People With Profound Intellectual and Multiple Disabilities
Motor activation is rarely integrated into the support of people with profound intellectual and multiple disabilities (PIMD), which might be the result of the limited evidence‐based knowledge in this field. Practitioners have recently been developing several motor initiatives for people with PIMD, but it remains unclear about what core elements the motor initiatives actually consist of and to what level of quality it is implemented in practice. This study aims to offer an overview and analysis of the content and quality of motor initiatives actually in use for people with PIMD. Motor initiatives were explored by asking practitioners to complete an online inventory form. Documents, expert knowledge, and observations were used to collect data about the characteristics of the motor initiatives. The quality of the motor initiatives which met our eligibility criteria, was analyzed on the basis of the level of evidence for their effectiveness. The inventory yielded 118 motor initiatives of which 17 met the eligibility criteria. We identified four motor initiatives reflecting an approach to motorically activate people with PIMD within various activities, three including power‐assisted exercises, three with aquatic exercises, two frameworks which integrated motor activities into their daily programs, two methods which included small‐scale activities, two rhythmic movement therapies, and one program including gross motor activities. We found limited indications for descriptive evidence from 17 initiatives, limited or no indications for theoretical evidence from 12 and five initiatives respectively, and none of the initiatives provided a causal level of evidence for effectiveness. A wide variety of motor initiatives is used in current practice to activate persons with PIMD, although their effectiveness is actually unproven. Science and practice should cooperate to develop an evidence‐based understanding to ensure more evidence‐based support for the motor activation of people with PIMD in the future
Building a circular supply chain:Achieving resilient operations with the circular economy
This paper highlights the fundamental contribution that supply chain professionals can make to the transition to a circular economy. It aims to provide a general understanding of how the circular economy and supply chain management fields are related to one another. By exploring the concept of a circular supply chain, the paper illustrates the role of supply chain professionals in operationalising circular economy initiatives within their organisations, as well as the opportunities and challenges they may encounter along the way. The paper also provides initialrecommendations for and examples of companies overcoming some of these challenges, based on the experiences of supply chain professionals involved in the research
Radiocarbon and geologic evidence reveal Ilopango volcano as source of the colossal ‘mystery’ eruption of 539/40 CE
Highlights
• Major eruption of Ilopango volcano, El Salvador occurred in the first half of the 6th century.
• Ilopango eruption is consistent with ‘mystery’ eruption of 540 CE that caused global cooling.
• Magnitude 7 event ranks as one of the 10 largest on Earth in past 7000 years.
• Impacts on the Maya of Central America were severe, including estimated 100,000 + fatalities.
Abstract
Ilopango volcano (El Salvador) erupted violently during the Maya Classic Period (250–900 CE) in a densely-populated and intensively-cultivated region of the southern Maya realm, causing regional abandonment of an area covering more than 20,000 km2. However, neither the regional nor global impacts of the Tierra Blanca Joven (TBJ) eruption in Mesoamerica have been well appraised due to limitations in available volcanological, chronological, and archaeological observations. Here we present new evidence of the age, magnitude and sulfur release of the TBJ eruption, establishing it as one of the two hitherto unidentified volcanic triggers of a period of stratospheric aerosol loading that profoundly impacted Northern Hemisphere climate and society between circa 536 and 550 CE. Our chronology is derived from 100 new radiocarbon measurements performed on three subfossil tree trunks enveloped in proximal TBJ pyroclastic deposits. We also reassess the eruption magnitude using terrestrial (El Salvador, Guatemala, Honduras) and near-shore marine TBJ tephra deposit thickness measurements. Together, our new constraints on the age, eruption size (43.6 km3 Dense Rock Equivalent of magma, magnitude = 7.0) and sulfur yield (∼9–90 Tg), along with Ilopango's latitude (13.7° N), squarely frame the TBJ as the major climate-forcing eruption of 539 or 540 CE identified in bipolar ice cores and sourced to the tropics. In addition to deepening appreciation of the TBJ eruption's impacts in Mesoamerica, linking it to the major Northern Hemisphere climatic downturn of the mid-6th century CE offers another piece in the puzzle of understanding Eurasian history of the period
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