177 research outputs found
A novel locus for autosomal recessive primary microcephaly (MCPH6) maps to 13q12.2
Key points:
• Autosomal recessive primary microcephaly (MCPH) is a
genetic disorder in which an affected subject is born
with a head circumference >3 SD below the expected
mean and is mentally retarded.
• We report a novel locus (MCPH6) mapped to chromosome
13q12.2 in a Brazilian family.
• The minimal critical region spans 6 Mb between markers
AL139378GT17 and D13S1244 with a maximum
two point lod score of 6.25
Kufor-Rakeb syndrome, pallido-pyramidal degeneration with supranuclear upgaze paresis and dementia, maps to 1p36
Kufor-Rakeb syndrome is an autosomal
recessive nigro-striatal-pallidal-pyramidal
neurodegeneration. The onset is in the
teenage years with clinical features of Parkinson’s
disease plus spasticity, supranuclear
upgaze paresis, and dementia. Brain
scans show atrophy of the globus pallidus
and pyramids and, later, widespread cerebral
atrophy. We report linkage in Kufor-
Rakeb syndrome to a 9 cM region of
chromosome 1p36 delineated by the markers
D1S436 and D1S2843, with a maximum
multipoint lod score of 3.6.
(J Med Genet 2001;38:680–682
Presence of Perfluoroalkyl Substances in Landfill Adjacent Surface Waters in North Carolina
Landfills pose an important public health risk, especially in historically disenfranchised communities that are disproportionately sited for landfills and in rural areas where private wells may be impacted. Landfills are major sources of perfluoroalkyl substances (PFAS) that migrate into the surrounding environment. This study characterized PFAS in surface waters adjacent to two landfills, one in Sampson County (SC) and one in Orange County (OC) in North Carolina. In addition to municipal solid waste and construction and demolition waste, the landfill in SC accepts industrial sludge from a chemical plant that produces proprietary PFAS. Over four months, 35 surface water samples were collected at upstream, landfill-adjacent, and downstream/downgradient sites. Thirty-four PFAS were analyzed using liquid chromatography with tandem mass spectroscopy. Of those, six novel and six legacy PFAS were detected. Legacy PFAS were detected in surface water near both landfills, with the highest concentrations adjacent to the landfill. Novel PFAS were only detected in surface water near the SC landfill and showed the highest concentrations adjacent to the landfill, indicating offsite migration of PFAS. These findings support the need for more comprehensive and frequent monitoring of groundwater and surface water wells near landfills and stricter regulation regarding the landfilling of industrial materials
Karak syndrome: a novel degenerative disorder of the basal ganglia and cerebellum
Two brothers are reported with early onset progressive
cerebellar ataxia, dystonia, spasticity, and intellectual
decline.
• Neuroradiology showed cerebellar atrophy and features
compatible with iron deposition in the putamen
(including the “eye of the tiger sign”) and substantia
nigra.
• Diagnosis was compatible with pantothenate kinase
associated neuropathy resulting from pantothenate
kinase 2 mutation (PKAN due to PANK2) but linkage to
PNAK2 was eliminated suggesting Karak syndrome to
be a novel disorder.
• The “eye of the tiger” sign has previously only been
reported to occur in PKAN due to PKAN
Autosomal recessive primary microcephaly: an analysis of locus heterogeneity and phenotypic variation
BACKGROUND AND OBJECTIVES: Locus heterogeneity is well established in autosomal recessive primary
microcephaly (MCPH) and to date five loci have been mapped. However, the relative contributions of
these loci have not been assessed and genotype-phenotype correlations have not been investigated.
DESIGN: A study population of 56 consanguineous families resident in or originating from northern
Pakistan was ascertained and assessed by the authors. A panel of microsatellite markers spanning
each of the MCPH loci was designed, against which the families were genotyped.
RESULTS: The head circumference of the 131 affected subjects ranged from 4 to 14 SD below the mean,
but there was little intrafamilial variation among affecteds (± 1 SD). MCPH5 was the most prevalent,
with 24/56 families consistent with linkage; 2/56 families were compatible with linkage to MCPH1,
10/56 to MCPH2, 2/56 to MCPH3, none to MCPH4, and 18/56 did not segregate with any of the
loci.
CONCLUSIONS: MCPH5 is the most common locus in this population. On clinical grounds alone, the
phenotype of families linked to each MCPH locus could not be distinguished. We have also shown that
further MCPH loci await discovery with a number of families as yet unlinked
The Variable X-ray and Near-IR Behavior of the Particularly Anomaloux X-ray Pulsar 1E 1048.1-5937
We present the results of X-ray and near-IR observations of the anomalous
X-ray pulsar 1E 1048.1-5937, believed to be a magnetar. This AXP underwent a
period of extreme variability during 2001-2004, but subsequently entered an
extended and unexpected quiescence in 2004-2006, during which we monitored it
with RXTE, CXO, and HST. Its timing properties were stable for >3 years
throughout the quiescent period. 1E 1048.1-5937 again went into outburst in
March 2007, which saw a factor of >7 total X-ray flux increase which was
anti-correlated with a pulsed fraction decrease, and correlated with spectral
hardening, among other effects. The near-IR counterpart also brightened
following the 2007 event. We discuss our findings in the context of the
magnetar and other models.Comment: 3 pages, 4 figures. To appear in the proceedings of the "40 Years of
Pulsars: Millisecond Pulsars, Magnetars and More" conference, held 12-17
August 2007, in Montreal QC (AIP, in press, eds: C. Bassa, Z. Wang, A.
Cumming, V. Kaspi
Quasi-classical Lie algebras and their contractions
After classifying indecomposable quasi-classical Lie algebras in low
dimension, and showing the existence of non-reductive stable quasi-classical
Lie algebras, we focus on the problem of obtaining sufficient conditions for a
quasi-classical Lie algebras to be the contraction of another quasi-classical
algebra. It is illustrated how this allows to recover the Yang-Mills equations
of a contraction by a limiting process, and how the contractions of an algebra
may generate a parameterized families of Lagrangians for pairwise
non-isomorphic Lie algebras.Comment: 17 pages, 2 Table
A Behavioural Foundation for Natural Computing and a Programmability Test
What does it mean to claim that a physical or natural system computes? One
answer, endorsed here, is that computing is about programming a system to
behave in different ways. This paper offers an account of what it means for a
physical system to compute based on this notion. It proposes a behavioural
characterisation of computing in terms of a measure of programmability, which
reflects a system's ability to react to external stimuli. The proposed measure
of programmability is useful for classifying computers in terms of the apparent
algorithmic complexity of their evolution in time. I make some specific
proposals in this connection and discuss this approach in the context of other
behavioural approaches, notably Turing's test of machine intelligence. I also
anticipate possible objections and consider the applicability of these
proposals to the task of relating abstract computation to nature-like
computation.Comment: 37 pages, 4 figures. Based on an invited Talk at the Symposium on
Natural/Unconventional Computing and its Philosophical Significance, Alan
Turing World Congress 2012, Birmingham, UK.
http://link.springer.com/article/10.1007/s13347-012-0095-2 Ref. glitch fixed
in 2nd. version; Philosophy & Technology (special issue on History and
Philosophy of Computing), Springer, 201
Expansions of algebras and superalgebras and some applications
After reviewing the three well-known methods to obtain Lie algebras and
superalgebras from given ones, namely, contractions, deformations and
extensions, we describe a fourth method recently introduced, the expansion of
Lie (super)algebras. Expanded (super)algebras have, in general, larger
dimensions than the original algebra, but also include the Inonu-Wigner and
generalized IW contractions as a particular case. As an example of a physical
application of expansions, we discuss the relation between the possible
underlying gauge symmetry of eleven-dimensional supergravity and the
superalgebra osp(1|32).Comment: Invited lecture delivered at the 'Deformations and Contractions in
Mathematics and Physics Workshop', 15-21 January 2006, Mathematisches
Forschungsinstitut Oberwolfach, German
Structural and dynamical properties of superfluid helium: a density functional approach
We present a novel density functional for liquid 4He, properly accounting for
the static response function and the phonon-roton dispersion in the uniform
liquid. The functional is used to study both structural and dynamical
properties of superfluid helium in various geometries. The equilibrium
properties of the free surface, droplets and films at zero temperature are
calculated. Our predictions agree closely to the results of ab initio Monte
Carlo calculations, when available. The introduction of a phenomenological
velocity dependent interaction, which accounts for backflow effects, is
discussed. The spectrum of the elementary excitations of the free surface and
films is studied.Comment: 37 pages, REVTeX 3.0, figures on request at [email protected]
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