2,771 research outputs found
Particle systems with a singular mean-field self-excitation. Application to neuronal networks
We discuss the construction and approximation of solutions to a nonlinear
McKean-Vlasov equation driven by a singular self-excitatory interaction of the
mean-field type. Such an equation is intended to describe an infinite
population of neurons which interact with one another. Each time a proportion
of neurons 'spike', the whole network instantaneously receives an excitatory
kick. The instantaneous nature of the excitation makes the system singular and
prevents the application of standard results from the literature. Making use of
the Skorohod M1 topology, we prove that, for the right notion of a 'physical'
solution, the nonlinear equation can be approximated either by a finite
particle system or by a delayed equation. As a by-product, we obtain the
existence of 'synchronized' solutions, for which a macroscopic proportion of
neurons may spike at the same time
Doctrine of atonement in Coleridge and Maurice
THE PURPOSE of this Thesis is to advocate a return-to a preAnsclinic
conception of Atonement theory, and to make an appeal for
renewed attention to the Patristic idea of a "Ransom". The Death
of Christ is a Ransom - a Price - which God has to pay for the
redemption of men.I do not profess to put forward any new discovery in this fully
excavated - even over excavated - field of Atonement controversy,
every inch of which has been examined and re-examined with a
minuteness which itself speaks for the importance of the subject
and its vital concern to the human heart; but it is the fact that
with Anselm there cane a radical change of emphasis which has more
or less coloured tho treatment of the doctrine ever since, and has
-
as I have been forced to think - introduced a certain obsession
or prejudice, a certain biassed point of view that has been too
readily accepted in dealing with the Atonement. Anseln gave the
death blow to the theory of a "Ransom to the Devil" which prevailed
before his tine. That theory has never really raised its head again.
It has in most books on the Atonement boon exhumed for a nomont
only to be battered with fresh blows and flung into the grave
again with renewed contumely. "That hideous theory", Rashdall
calls it,- "the coarse mythology of the Ransom theory". And ho
says, "Never in the whole history of Christian thought has a doct¬
rine been so decidedly destroyed by criticism and more univorsally
abandoned".(Ideas and Ideals.158)I venture to think it is just this universal abandonment of it,
this utter refusal to look at what it means and to nako use of
(ii)
the principle underlying it that has introduced into the doctrine
and retained in the doctrine a sense of obscurity and mystery
which need not bo there. As an act of God, and an outcone of
God'* nature and character, the Atonement is naturally mysterious,
hike all the greatest things it ultimately - exit in mysterium. •
hut apart from the welcome grandeur of this inevitable and aweinspiring
mystery, one fools - in reading the history of the
doctrine up to the prosent timo, in tracing the efforts of tho
greatest writers to find an explanation of the fact - one cannot
resist the impression that there is a difficulty which ought, to
yield, there is a sense of baffled effort, to some extent there i3
the fooling of a koy lost, a missing dlaitent that, were it found,
would illumine a dark region.I may indicate the Scope of the Thesis as follows
I shall first of all deal with the two writers, Coleridge
and Maurice, in turn, indicating in each case the various
points of their actual teaching 011 the Atonement. I shall
then endeavour to show the affinity of their leading principles with that theory to which I wish to call fresh attention, viz,- the Patristic theory of Ransom. This theory itself
will then require some description,-and I shall set it forth,
briefly, as it appears in the pages of Gregory of hyssa -
where we have it in its purest form. Kext will follow -
an account of Anselm's refutation of the theory - my own
counter criticism of Anselm and of the whole "Satisfaction"
idea in Atonement doctrine - criticism of the purely subjective theory of "Moral Influence", showing the defects
of that theory as an explanation of the Atonement, and
pointing out how essentially the teaching of Coleridge and
Maurice is to be distinguished from it. This will be followed, finally, by a constructive summary of the doctrine
Earth resources evaluation for New Mexico by LANDSAT-2
The author has identified the following significant results. The Middle Rio Grande project has not yet progressed to the point where mineral exploration sites can be chosen; however, there does appear to be some correlation between the known structure and mineral deposits and the LANDSAT lineament map. A circular feature identified in the southern Magdalena Mountains on LANDSAT-1 imagery agrees well with the location of a newly proposed caldron complex. Several recognized and unrecognized circular features were identified on imagery of the Mogollon-Datil volcanic field. A check of aeromagnetic maps for New Mexico found that the circular features on the LANDSAT imagery showed up as areas of generally high magnetic intensity
Jumble Java Byte Code to Measure the Effectiveness of Unit Tests
Jumble is a byte code level mutation testing tool for Java which inter-operates with JUnit. It has been designed to operate in an industrial setting with large projects. Heuristics have been included to speed the checking of mutations, for example, noting which test fails for each mutation and running this first in subsequent mutation checks. Significant effort has been put into ensuring that it can test code which uses custom class loading and reflection. This requires careful attention to class path handling and coexistence with foreign class-loaders. Jumble is currently used on a continuous basis within an agile programming environment with approximately 370,000 lines of Java code under source control. This checks out project code every fifteen minutes and runs an incremental set of unit tests and mutation tests for modified classes. Jumble is being made available as open source
Geologic analysis of ERTS-1 imagery for the State of New Mexico
There are no author-identified significant results in this report
Instrumental oscillations in RHESSI count rates during solar flares
Aims: We seek to illustrate the analysis problems posed by RHESSI spacecraft
motion by studying persistent instrumental oscillations found in the
lightcurves measured by RHESSI's X-ray detectors in the 6-12 keV and 12-25 keV
energy range during the decay phase of the flares of 2004 November 4 and 6.
Methods: The various motions of the RHESSI spacecraft which may contribute to
the manifestation of oscillations are studied. The response of each detector in
turn is also investigated. Results: We find that on 2004 November 6 the
observed oscillations correspond to the nutation period of the RHESSI
instrument. These oscillations are also of greatest amplitude for detector 5,
while in the lightcurves of many other detectors the oscillations are small or
undetectable. We also find that the variation in detector pointing is much
larger during this flare than the counterexample of 2004 November 4.
Conclusions: Sufficiently large nutation motions of the RHESSI spacecraft lead
to clearly observable oscillations in count rates, posing a significant hazard
for data analysis. This issue is particularly problematic for detector 5 due to
its design characteristics. Dynamic correction of the RHESSI counts, accounting
for the livetime, data gaps, and the transmission of the bi-grid collimator of
each detector, is required to overcome this issue. These corrections should be
applied to all future oscillation studies.Comment: 8 pages, 10 figure
Monomorphic subtelomeric DNA in the filamentous fungus, Metarhizium anisopliae, contains a RecQ helicase-like gene.
In most filamentous fungi, telomere-associated sequences (TASs) are polymorphic, and the presence of restriction fragment length polymorphisms (RFLPs) may permit the number of chromosome ends to be estimated from the number of telomeric bands obtained by restriction digestion. Here, we describe strains of Metarhizium, Gliocladium and Paecilomyces species in which only one or a few telomeric bands of unequal intensity are detectable by Southern hybridization, indicating that interchromosomal TAS exchange occurs. We also studied an anomalous strain of Metarhizium anisopliae, which produces polymorphic telomeric bands larger than 8 kb upon digestion of genomic DNA with XhoI. In this case, the first XhoI site in from the chromosome end must lie beyond the presumed monomorphic region. Cloned telomeres from this strain comprise 18?26 TTAGGG repeats, followed at the internal end of the telomere tract by five repeats of the telomere-like sequence TAAACGCTGG. An 8.1-kb TAS clone also contains a gene for a RecQ-like helicase, designated TAH1, suggesting that this TAS is analogous to the Y elements in yeast and the subtelomeric helicase ORFs of Ustilago maydis (UTASRecQ) and Magnaporthe grisea (TLH1). The TAS in the anomalous strain of M. anisopliae, however, appears distinct from these in that it is found at most telomeres and its predicted protein product possesses a significantly longer N-terminal region in comparison to the M. grisea and U. maydis helicases. Hybridization analyses showed that TAH1 homologues are present in all other anomalous M. anisopliae strains studied, as well as in some other polymorphic strains, where the recQ-like gene also appears to be telomere-associated.Published online: 2 June 2005
Automated identification of neurons and their locations
Individual locations of many neuronal cell bodies (>10^4) are needed to
enable statistically significant measurements of spatial organization within
the brain such as nearest-neighbor and microcolumnarity measurements. In this
paper, we introduce an Automated Neuron Recognition Algorithm (ANRA) which
obtains the (x,y) location of individual neurons within digitized images of
Nissl-stained, 30 micron thick, frozen sections of the cerebral cortex of the
Rhesus monkey. Identification of neurons within such Nissl-stained sections is
inherently difficult due to the variability in neuron staining, the overlap of
neurons, the presence of partial or damaged neurons at tissue surfaces, and the
presence of non-neuron objects, such as glial cells, blood vessels, and random
artifacts. To overcome these challenges and identify neurons, ANRA applies a
combination of image segmentation and machine learning. The steps involve
active contour segmentation to find outlines of potential neuron cell bodies
followed by artificial neural network training using the segmentation
properties (size, optical density, gyration, etc.) to distinguish between
neuron and non-neuron segmentations. ANRA positively identifies 86[5]% neurons
with 15[8]% error (mean[st.dev.]) on a wide range of Nissl-stained images,
whereas semi-automatic methods obtain 80[7]%/17[12]%. A further advantage of
ANRA is that it affords an unlimited increase in speed from semi-automatic
methods, and is computationally efficient, with the ability to recognize ~100
neurons per minute using a standard personal computer. ANRA is amenable to
analysis of huge photo-montages of Nissl-stained tissue, thereby opening the
door to fast, efficient and quantitative analysis of vast stores of archival
material that exist in laboratories and research collections around the world.Comment: 38 pages. Formatted for two-sided printing. Supplemental material and
software available at http://physics.bu.edu/~ainglis/ANRA
Osteosarcopenic Obesity Syndrome: What Is It and How Can It Be Identified and Diagnosed?
Conditions related to body composition and aging, such as osteopenic obesity, sarcopenia/sarcopenic obesity, and the newly termed osteosarcopenic obesity (triad of bone muscle and adipose tissue impairment), are beginning to gain recognition. However there is still a lack of definitive diagnostic criteria for these conditions. Little is known about the long-term impact of these combined conditions of osteoporosis, sarcopenia, and obesity in older adults. Many may go undiagnosed and progress untreated. Therefore, the objective of this research is to create diagnostic criteria for osteosarcopenic obesity in older women. The proposed diagnostic criteria are based on two types of assessments: physical, via body composition measurements, and functional, via physical performance measures. Body composition measurements such as T-scores for bone mineral density, appendicular lean mass for sarcopenia, and percent body fat could all be obtained via dual energy X-ray absorptiometry. Physical performance tests: handgrip strength, one-leg stance, walking speed, and sit-to-stand could be assessed with minimal equipment. A score could then be obtained to measure functional decline in the older adult. For diagnosing osteosarcopenic obesity and other conditions related to bone loss and muscle loss combined with obesity, a combination of measures may more adequately improve the assessment process
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