145 research outputs found
No major flaws in "Identification of individuals by trait prediction using whole-genome sequencing data"
In a recently published PNAS article, we studied the identifiability of genomic samples using machine learning methods [Lippert et al., 2017]. In a response, Erlich [2017]
argued that our work contained major flaws. The main technical critique of Erlich [2017] builds on a simulation experiment that shows that our proposed algorithm, which
uses only a genomic sample for identification, performed no better than a strategy that uses demographic variables. Below, we show why this comparison is misleading and
provide a detailed discussion of the key critical points in our analyses that have been brought up in Erlich [2017] and in the media. Further, not only faces may be derived
from DNA, but a wide range of phenotypes and demographic variables. In this light, the main contribution of Lippert et al. [2017] is an algorithm that identifies genomes of
individuals by combining multiple DNA-based predictive models for a myriad of traits
Analyzing multitarget activity landscapes using protein-ligand interaction fingerprints: interaction cliffs.
This is the original submitted version, before peer review. The final peer-reviewed version is available from ACS at http://pubs.acs.org/doi/abs/10.1021/ci500721x.Activity landscape modeling is mostly a descriptive technique that allows rationalizing continuous and discontinuous SARs. Nevertheless, the interpretation of some landscape features, especially of activity cliffs, is not straightforward. As the nature of activity cliffs depends on the ligand and the target, information regarding both should be included in the analysis. A specific way to include this information is using protein-ligand interaction fingerprints (IFPs). In this paper we report the activity landscape modeling of 507 ligand-kinase complexes (from the KLIFS database) including IFP, which facilitates the analysis and interpretation of activity cliffs. Here we introduce the structure-activity-interaction similarity (SAIS) maps that incorporate information on ligand-target contact similarity. We also introduce the concept of interaction cliffs defined as ligand-target complexes with high structural and interaction similarity but have a large potency difference of the ligands. Moreover, the information retrieved regarding the specific interaction allowed the identification of activity cliff hot spots, which help to rationalize activity cliffs from the target point of view. In general, the information provided by IFPs provides a structure-based understanding of some activity landscape features. This paper shows examples of analyses that can be carried out when IFPs are added to the activity landscape model.M-L is very
grateful to CONACyT (No. 217442/312933) and the Cambridge Overseas Trust for funding. AB
thanks Unilever for funding and the European Research Council for a Starting Grant (ERC-2013-
StG-336159 MIXTURE). J.L.M-F. is grateful to the School of Chemistry, Department of
Pharmacy of the National Autonomous University of Mexico (UNAM) for support. This work
was supported by a scholarship from the Secretariat of Public Education and the Mexican
government
Eating disorders: the current status of molecular genetic research
Anorexia nervosa (AN) and bulimia nervosa (BN) are complex disorders characterized by disordered eating behavior where the patient’s attitude towards weight and shape, as well as their perception of body shape, are disturbed. Formal genetic studies on twins and families suggested a substantial genetic influence for AN and BN. Candidate gene studies have initially focused on the serotonergic and other central neurotransmitter systems and on genes involved in body weight regulation. Hardly any of the positive findings achieved in these studies were unequivocally confirmed or substantiated in meta-analyses. This might be due to too small sample sizes and thus low power and/or the genes underlying eating disorders have not yet been analyzed. However, some studies that also used subphenotypes (e.g., restricting type of AN) led to more specific results; however, confirmation is as yet mostly lacking. Systematic genome-wide linkage scans based on families with at least two individuals with an eating disorder (AN or BN) revealed initial linkage regions on chromosomes 1, 3 and 4 (AN) and 10p (BN). Analyses on candidate genes in the chromosome 1 linkage region led to the (as yet unconfirmed) identification of certain variants associated with AN. Genome-wide association studies are under way and will presumably help to identify genes and pathways involved in these eating disorders. The elucidation of the molecular mechanisms underlying eating disorders might improve therapeutic approaches
Lipopolysaccharide treatment suppresses spontaneously developing ankylosing enthesopathy in B10.BR male mice: The potential role of interleukin-10
The physical properties of minor aquifers in England and Wales
This report is the result of a three-year collaborative project
between the British Geological Survey and the Environment
Agency. The aim of the project has been to collect, collate
and present information concerning the physical hydraulic
properties of the minor aquifers in England and Wales.
These properties include hydraulic conductivity, porosity,
transmissivity and storage coefficient. In addition, specific
capacity (yield per unit drawdown) values are included for
many of the formations described, together with yields for
those formations where aquifer properties data are sparse.
Although the parameters studied were limited in number,
the study has proven to be complex for several reasons.
Firstly the aquifers themselves are hydraulically complicated.
They are bodies of rock, sometimes with indeterminate
boundaries, which are heterogeneous either because of
sedimentological factors in the case of the Cainozoic
aquifers, or because of the effects of fracturing in older formations.
This heterogeneity presents several problems.
Firstly, hydraulic tests on such materials often violate the
classical assumptions used in the test analysis, and the complexity
of the aquifers makes interpolation between data
points difficult. Secondly, the physical properties of the
aquifers are often scale dependent, so that the value of a
parameter at one scale may not be appropriate for use at a
larger or smaller scale. Thirdly, there are problems of data
quality and quantity which are particularly significant for
these smaller aquifers. The quality of the pumping tests is
variable and many results are from short duration pumping
tests which are designed more to assess the yields of boreholes
than to examine the properties of the aquifer. Also,
data can be very irregularly distributed, being a product
mainly of the evolving requirements of groundwater users
and not of well-planned resource assessments. This irregular
spacing can be both vertical as well as lateral, as in the case
of thick structurally complex sequences with only scattered
productive horizons.
Awareness of these inherent hydrogeological factors
dictated the project’s approach, which was to collect both
data and knowledge about the aquifers. This permits the
report to describe not only the magnitudes and variability of
the aquifer parameters at a given tested locality, but also to
provide some insight into factors controlling the properties,
so that the results can be more confidently extrapolated.
Project resources were therefore initially employed in data
collection. This involved a detailed search through Agency
records, with additional information from BGS, published
and unpublished literature. Most of the data obtained were
from analysed pumping tests, the results of which were
entered in a database. The latter originally housed data on
the major aquifers, collected under a preceding project, but
the database needed to be significantly altered and expanded
so as to manage efficiently the much larger number of
aquifers involved. It was also linked with the BGS Core
Analysis Database. The result comprises the National
Aquifer Properties Database which is now a major UK geoscience
resource, with data from more than 8000 pumping
test analyses at over 8250 sites.
The second main strand of the project was the collection
and summarising of knowledge about the aquifers. In
addition to the collection of reports of hydrogeological
studies and a literature survey, expert opinion was canvassed.
The latter is a vital source of information that is not
often published.
The results of these two approaches are synthesised in this
report. After the introductory sections each chapter takes the
form of a detailed review of the physical properties of a
group of minor aquifers, subdivided as appropriate on stratigraphic
or geographical grounds. The chapters are arranged
in order of increasing age. The purpose of the review is to
present the magnitudes and variability of the data (mainly
from the database, but with other examples) in the context of
current understanding of the aquifer systems involved and
the controls on the data. To that end the review includes geological,
geographical and physical hydrogeological aspects
of the aquifers. Useful summaries of data from the database
are included on the accompanying CD-ROM.
The intention of the report is therefore to acquaint the
reader with the aquifer properties data values that characterise
the aquifers in the context of what is known about the
complexities of their hydraulic structure and the physical
controls on the data. The reader is specifically dissuaded
from taking raw values out of context. A further purpose of
the report is provide a comprehensive set of references by
which the reader can obtain more detailed information about
particular areas of interest in an aquifer.
As a result of the collection and review of information
about the physical properties of the minor aquifers in
England and Wales, it is apparent that there are many areas
in which knowledge is inadequate. For example, a critical
comparison of the equivalent aquifer systems in the London
and Hampshire basins was not possible in other than the
most general terms. Similarly, the lateral variability in
aquifer properties in the Lower Cretaceous aquifers of the
Weald is suspected to arise partly from fault-controlled compartmentalisation,
but the role of the faults is not well
enough understood for predictive purposes. For all the effort
expended on geological characterisation over almost two
centuries of detailed study of English Jurassic rocks, the
flow systems of the numerous arenaceous and carbonate
minor aquifers of that system are in general poorly characterised.
Very localised borehole development and the
effects of tapping complex multi-aquifer sequences mean
that the fracture-dominant, structurally-affected systems of
older rocks of Palaeozoic age are in many cases barely conceptualised.
Such gaps in our knowledge are inevitable considering
the paucity of data. Nevertheless, the project has
provided the first opportunity to review comprehensively the
aquifer properties of this second rank of British aquifers
whose role is so important in providing local sources of
water supply for both private and public use
Trauma-informed care and practice for eating disorders: personal and professional perspectives of lived experiences
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