2,599 research outputs found
Chemical and forensic analysis of JFK assassination bullet lots: Is a second shooter possible?
The assassination of President John Fitzgerald Kennedy (JFK) traumatized the
nation. In this paper we show that evidence used to rule out a second assassin
is fundamentally flawed. This paper discusses new compositional analyses of
bullets reportedly to have been derived from the same batch as those used in
the assassination. The new analyses show that the bullet fragments involved in
the assassination are not nearly as rare as previously reported. In particular,
the new test results are compared to key bullet composition testimony presented
before the House Select Committee on Assassinations (HSCA). Matches of bullets
within the same box of bullets are shown to be much more likely than indicated
in the House Select Committee on Assassinations' testimony. Additionally, we
show that one of the ten test bullets is considered a match to one or more
assassination fragments. This finding means that the bullet fragments from the
assassination that match could have come from three or more separate bullets.
Finally, this paper presents a case for reanalyzing the assassination bullet
fragments and conducting the necessary supporting scientific studies. These
analyses will shed light on whether the five bullet fragments constitute three
or more separate bullets. If the assassination fragments are derived from three
or more separate bullets, then a second assassin is likely, as the additional
bullet would not easily be attributable to the main suspect, Mr. Oswald, under
widely accepted shooting scenarios [see Posner (1993), Case Closed, Bantam, New
York].Comment: Published in at http://dx.doi.org/10.1214/07-AOAS119 the Annals of
Applied Statistics (http://www.imstat.org/aoas/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Response to the Letter to the Editor
This paper has attracted interest around the world from the media (both TV
and newspapers). In addition, we have received letters, emails and telephone
calls. One of our favorites was a voicemail message asking us to return a call
to Australia at which point we would learn who really killed JFK. We welcome
the opportunity to respond to the letter to the editor from Mr. Fiorentino. Mr.
Fiorentino claims that our ``statement relating to the likelihood of a second
assassin based on the premise of three or more separate bullets is demonstrably
false.'' In response we would like to simply quote from page 327 of Gerald
Posner's book Case Closed, one of the most well known works supporting the
single assassin theory: ``If Connally was hit by another bullet, it had to be
fired from a second shooter, since the Warren Commission's own reconstructions
showed that Oswald could not have operated the bolt and refired in 1.4
seconds.'' Mr. Fiorentino also claims that the ``second fatal flaw is the use
of a rather uncomplicated formula based on Bayes Theorem.'' Let denote the
evidence and denote the theory that there were just two bullets (and hence
a single shooter). We used Bayes Theorem to hypothetically calculate
from and the prior probability . In order to make ten
times more likely than , the ratio of the prior probabilities
[i.e., ] would have to be greater than 15. Thus, we again
conclude that this casts serious doubt on Dr. Guinn's conclusion that the
evidence supported just two bullets. Sadly, this is far from the first time
that probability has been misunderstood and/or misapplied in a case of public
interest. A notable British example is the Clark case. See Nobles and Schiff
(2005) for details. Finally, we welcome and, in fact, encourage members of the
scientific community to provide alternative analyses of the data.Comment: Published in at http://dx.doi.org/10.1214/07-AOAS154 the Annals of
Applied Statistics (http://www.imstat.org/aoas/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Transverse force on a quantized vortex in a superconductor
The total transverse force acting on a quantized vortex in a type-II
superconductor determines the Hall response in the mixed state, yet a consensus
as to its correct form is still lacking. In this paper we present an
essentially exact expression for this force, valid in the superclean limit,
which was obtained by generalizing the recent work by Thouless, Ao, and Niu [D.
J. Thouless, P. Ao, and Q. Niu, Phys. Rev. Lett. 76, 3758 (1996)] on the Magnus
force in a neutral superfluid. We find the transverse force per unit length to
be , where is the sum of the
mass densities of the normal and superconducting components, is a vector
parallel to the line vortex with a magnitude equal to the quantized
circulation, and is the vortex velocity.Comment: 4 pages, Revtex, 1 figur
Environmental and genetic influences on neurocognitive development: the importance of multiple methodologies and time-dependent intervention
Genetic mutations and environmental factors dynamically influence gene expression and developmental trajectories at the neural, cognitive, and behavioral levels. The examples in this article cover different periods of neurocognitive development—early childhood, adolescence, and adulthood—and focus on studies in which researchers have used a variety of methodologies to illustrate the early effects of socioeconomic status and stress on brain function, as well as how allelic differences explain why some individuals respond to intervention and others do not. These studies highlight how similar behaviors can be driven by different underlying neural processes and show how a neurocomputational model of early development can account for neurodevelopmental syndromes, such as autism spectrum disorders, with novel implications for intervention. Finally, these studies illustrate the importance of the timing of environmental and genetic factors on development, consistent with our view that phenotypes are emergent, not predetermined
Monte Carlo simulation method for Laughlin-like states in a disk geometry
We discuss an alternative accurate Monte Carlo method to calculate the
ground-state energy and related quantities for Laughlin states of the
fractional quantum Hall effect in a disk geometry. This alternative approach
allows us to obtain accurate bulk regime (thermodynamic limit) values for
various quantities from Monte Carlo simulations with a small number of
particles (much smaller than that needed with standard Monte Carlo approaches).Comment: 13 pages, 6 figures, 2 table
Incidence of adult Huntington's disease in the UK: a UK-based primary care study and a systematic review.
OBJECTIVES: The prevalence of Huntington's disease (HD) recorded in the UK primary care records has increased twofold between 1990 and 2010. This investigation was undertaken to assess whether this might be due to an increased incidence. We have also undertaken a systematic review of published estimates of the incidence of HD. SETTING: Incident patients with a new diagnosis of HD were identified from the primary care records of the Clinical Practice Research Datalink (CPRD). The systematic review included all published estimates of the incidence of HD in defined populations. PARTICIPANTS: A total of 393 incident cases of HD were identified from the CPRD database between 1990 and 2010 from a total population of 9,282,126 persons. PRIMARY AND SECONDARY OUTCOME MEASURES: The incidence of HD per million person-years was estimated. From the systematic review, the extent of heterogeneity of published estimates of the incidence of HD was examined using the I(2) statistic. RESULTS: The data showed that the incidence of HD has remained constant between 1990 and 2010 with an overall rate of 7.2 (95% CI 6.5 to 7.9) per million person-years. The systematic review identified 14 independent estimates of incidence with substantial heterogeneity and consistently lower rates reported in studies from East Asia compared with those from Australia, North America and some--though not all--those from Europe. Differences in incidence estimates did not appear to be explained solely by differences in case ascertainment or diagnostic methods. CONCLUSIONS: The rise in the prevalence of diagnosed HD in the UK, between 1990 and 2010, cannot be attributed to an increase in incidence. Globally, estimates of the incidence of HD show evidence of substantial heterogeneity with consistently lower rates in East Asia and parts of Europe. Modifiers may play an important role in determining the vulnerability of different populations to expansions of the HD allele
Hypernetted-chain study of broken rotational symmetry states for the = 1/3 fractional quantum Hall effect and other fractionally filled Landau levels
We investigate broken rotational symmetry (BRS) states for the fractional
quantum Hall effect (FQHE) at 1/3-filling of the valence Landau level (LL).
Recent Monte Carlo calculations by Musaelian and Joynt [J. Phys.: Condens.\
Matter {\bf 8}, L105 (1996)] suggest that Laughlin's state becomes unstable to
a BRS state for some critical finite thickness value. We study in detail the
properties of such state by performing a hypernetted-chain calculation that
gives results in the thermodynamic limit, complementing other methods which are
limited to a finite number of particles. Our results indicate that while
Laughlin's state is stable in the lowest LL, in higher LLs a BRS instability
occurs, perhaps indicating the absence of FQHE at partial fillings of higher
LLs. Possible connections to the newly discovered liquid crystalline phases in
higher LLs are also discussed.Comment: 7 pages including 3 eps figure
Charge and current oscillations in Fractional quantum Hall systems with edges
Stationary solutions of the Chern-Simons effective field theory for the
fractional quantum Hall systems with edges are presented for Hall bar, disk and
annulus. In the infinitely long Hall bar geometry (non compact case), the
charge density is shown to be monotonic inside the sample. In sharp contrast,
spatial oscillatory modes of charge density are found for the two circular
geometries, which indicate that in systems with compact geometry, charge and
current exist also far from the edges.Comment: 16 pages, 6 figures Revte
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