16,096 research outputs found
Anticipation and Adaptation in Particulate Matter Policy: The European Union, the Netherlands, and United States
The evolution of particulate matter (PM) air quality policy in the European Union and in the
United States between 1970 and the present has been atypical. The US government and the
European Commission have mandated scheduled reviews of PM policy over the past three
decades and have updated that policy to new scientific information on multiple occasions.
The use of planned adaptation over such a long period and in this manner, as a means to
deal with uncertainty, has not often been reproduced in air quality policy.
Furthermore, particulate matter policy in the EU and US does not conform to the
commonly held perception that the EU’s environmental policies are, by and large, more
precautionary than the respective policies in the United States. The US decisions to adopt air
quality standards for PM10 and PM2.5, in 1987 and 1997 respectively, led those in the EU by
approximately nine years.
An analysis of the comparative stringency of the PM standards in
the US and EU shows that the PM2.5 standard the US implemented in 1997 is more stringent
than the standards that have been proposed in the EU by the European Commission and the
European Parliament. In September this year, the US repealed their annual standard for
PM10. Prior to that, however, the annual PM10 standard the EU implemented in 1999 was
more stringent than the one the US adopted in 1987. The daily PM10 standards in the EU
and US are of similar stringency. In the Appendix, these comparisons in stringency are
discussed in more detail.
The differences between the EU and US policies are remarkable because they are
based on the same science and therefore reflect dissimilar processes of interpreting that
science and the uncertainties inherent in it. The two cases themselves focus on the sciencepolicy
interfaces for their respective governing bodies. The EU case also looks at the
science-policy interface in the Netherlands. The US case also examines policies for sulfur
dioxides that relate to the PM policies. The remainder of this summary discusses how
characteristics of the science-policy interfaces may have led to the differences in outcomes
Synthesis of new chiral organosulfur donors with hydrogen bonding functionality and their first charge transfer salts
The syntheses of a range of enantiopure organosulfur donors with hydrogen bonding groups are described including TTF related materials with two, four, six and eight hydroxyl groups and multiple stereogenic centres and a pair of chiral N-substituted BEDT-TTF acetamides. Three charge transfer salts of enantiopure poly-hydroxy-substituted donors are reported, including a 4:1 salt with the meso stereoisomer of the dinuclear [Fe2(oxalate)5 ]4- anion in which both cation and anion have chiral components linked together by hydrogen bonding, and a semiconducting salt with triiodide
The structural effects of mutations can aid in differential phenotype prediction of beta-myosin heavy chain (Myosin-7) missense variants
MOTIVATION: High-throughput sequencing platforms are increasingly used to screen patients with genetic disease for pathogenic mutations, but prediction of the effects of mutations remains challenging. Previously we developed SAAPdap (Single Amino Acid Polymorphism Data Analysis Pipeline) and SAAPpred (Single Amino Acid Polymorphism Predictor) that use a combination of rule-based structural measures to predict whether a missense genetic variant is pathogenic. Here we investigate whether the same methodology can be used to develop a differential phenotype predictor, which, once a mutation has been predicted as pathogenic, is able to distinguish between phenotypes-in this case the two major clinical phenotypes (hypertrophic cardiomyopathy, HCM, and dilated cardiomyopathy, DCM) associated with mutations in the beta-myosin heavy chain (MYH7) gene product (Myosin-7). RESULTS: A random forest predictor trained on rule-based structural analyses together with structural clustering data gave a Matthews' correlation coefficient (MCC) of 0.53 (accuracy, 75%). A post hoc removal of machine learning models that performed particularly badly, increased the performance (MCC = 0.61, Acc = 79%). This proof of concept suggests that methods used for pathogenicity prediction can be extended for use in differential phenotype prediction
Charge transfer complexes and radical cation salts of chiral methylated organosulfur donors
The single crystal X-ray structure of the all-axial conformer of the (R,R,R,R) enantiomer of the chiral donor tetramethyl-BEDT-TTF (TM-BEDT-TTF) was described and compared to the all-equatorial conformer. (S,S,S,S)-Tetramethyl-BEDT-TTF formed crystalline 1 : 1 complexes with TCNQ and TCNQ-F4, as well as a THF solvate of the TCNQ complex. Donors bis((2S,4S)-pentane-2,4-dithio)tetrathiafulvalene and (ethylenedithio)((2S,4S)-pentane-2,4-dithio)tetrathiafulvalene, which contain seven-membered rings bearing chirally oriented methyl groups, only formed complexes with TCNQ-F4. The TCNQ-F4 complexes contain planar organosulfur systems, in contrast to the TCNQ complexes in which there is minimal charge transfer. A variety of crystal packing modes were observed. Electrocrystallization experiments with both enantiomers and the racemic form of tetramethyl-BEDT-TTF afforded mixed valence radical cation salts with the AsF6 and SbF6 anions formulated as (TM-BEDT-TTF)2XF6 (X = As, Sb). Electrical conductivity was only found in one charge transfer complex, while the radical cation salts are all semiconducting
Limit on the mass of a long-lived or stable gluino
We reinterpret the generic CDF charged massive particle limit to obtain a
limit on the mass of a stable or long-lived gluino. Various sources of
uncertainty are examined. The -hadron spectrum and scattering cross sections
are modeled based on known low-energy hadron physics and the resultant
uncertainties are quantified and found to be small compared to uncertainties
from the scale dependence of the NLO pQCD production cross sections. The
largest uncertainty in the limit comes from the unknown squark mass: when the
squark -- gluino mass splitting is small, we obtain a gluino mass limit of 407
GeV, while in the limit of heavy squarks the gluino mass limit is 397 GeV. For
arbitrary (degenerate) squark masses, we obtain a lower limit of 322 GeV on the
gluino mass. These limits apply for any gluino lifetime longer than
ns, and are the most stringent limits for such a long-lived or stable gluino.Comment: 15 pages, 5 figures, accepted for publication in JHE
Mechanical Stress Inference for Two Dimensional Cell Arrays
Many morphogenetic processes involve mechanical rearrangement of epithelial
tissues that is driven by precisely regulated cytoskeletal forces and cell
adhesion. The mechanical state of the cell and intercellular adhesion are not
only the targets of regulation, but are themselves likely signals that
coordinate developmental process. Yet, because it is difficult to directly
measure mechanical stress {\it in vivo} on sub-cellular scale, little is
understood about the role of mechanics of development. Here we present an
alternative approach which takes advantage of the recent progress in live
imaging of morphogenetic processes and uses computational analysis of high
resolution images of epithelial tissues to infer relative magnitude of forces
acting within and between cells. We model intracellular stress in terms of bulk
pressure and interfacial tension, allowing these parameters to vary from cell
to cell and from interface to interface. Assuming that epithelial cell layers
are close to mechanical equilibrium, we use the observed geometry of the two
dimensional cell array to infer interfacial tensions and intracellular
pressures. Here we present the mathematical formulation of the proposed
Mechanical Inverse method and apply it to the analysis of epithelial cell
layers observed at the onset of ventral furrow formation in the {\it
Drosophila} embryo and in the process of hair-cell determination in the avian
cochlea. The analysis reveals mechanical anisotropy in the former process and
mechanical heterogeneity, correlated with cell differentiation, in the latter
process. The method opens a way for quantitative and detailed experimental
tests of models of cell and tissue mechanics
Several types of types in programming languages
Types are an important part of any modern programming language, but we often
forget that the concept of type we understand nowadays is not the same it was
perceived in the sixties. Moreover, we conflate the concept of "type" in
programming languages with the concept of the same name in mathematical logic,
an identification that is only the result of the convergence of two different
paths, which started apart with different aims. The paper will present several
remarks (some historical, some of more conceptual character) on the subject, as
a basis for a further investigation. The thesis we will argue is that there are
three different characters at play in programming languages, all of them now
called types: the technical concept used in language design to guide
implementation; the general abstraction mechanism used as a modelling tool; the
classifying tool inherited from mathematical logic. We will suggest three
possible dates ad quem for their presence in the programming language
literature, suggesting that the emergence of the concept of type in computer
science is relatively independent from the logical tradition, until the
Curry-Howard isomorphism will make an explicit bridge between them.Comment: History and Philosophy of Computing, HAPOC 2015. To appear in LNC
3D multi-agent models for protein release from PLGA spherical particles with complex inner morphologies
In order to better understand and predict the release of proteins from bioerodible micro- or nanospheres, it is important to know the influences of different initial factors on the release mechanisms. Often though it is difficult to assess what exactly is at the origin of a certain dissolution profile. We propose here a new class of fine-grained multi-agent models built to incorporate
increasing complexity, permitting the exploration of the role of different parameters, especially that of the internal morphology of the spheres, in the exhibited release profile. This approach, based on Monte-Carlo (MC) and Cellular Automata (CA) techniques, has permitted the testing of various assumptions and hypotheses about several experimental systems of nanospheres encapsulating proteins. Results have confirmed that this modelling approach
has increased the resolution over the complexity involved, opening promising perspectives for future developments, especially complementing in vitro experimentation
NHS waiting lists and evidence of national or local failure: analysis of health service data.
OBJECTIVES: To investigate the national distribution of prolonged waiting for elective day case and inpatient surgery, and to examine associations of prolonged waiting with markers of NHS capacity, activity in the independent sector, and need. SETTING: NHS hospital trusts in England. POPULATION: People waiting for elective treatment in the specialties of general surgery; ear, nose and throat surgery; ophthalmic surgery; and trauma and orthopaedic surgery. MAIN OUTCOME MEASURE: Numbers of people waiting six months or longer (prolonged waiting). Characteristics of trusts with large numbers waiting six months or longer were examined by using logistic regression. RESULTS: The distribution of numbers of people waiting for day case or elective surgery in all the specialties examined was highly positively skewed. Between 52% and 83% of patients waiting longer than six months in the specialties studied were found in one quarter of trusts, which in turn contributed 23-45% of the national throughput specific to the specialty. In general, there was little evidence to show that capacity (measured by numbers of operating theatres, dedicated day case theatres, available beds, and bed occupancy rate) or independent sector activity were associated with prolonged waiting, although exceptions were noted for individual specialties. There was consistent evidence showing an increase in prolonged waiting, with increased numbers of anaesthetists across all specialties and with increased bed occupancy rates for ear, nose and throat surgery. Markers of greater need for health care, such as deprivation score and rate of limiting long term illness, were inversely associated with prolonged waiting. CONCLUSION: In most instances, substantial numbers of patients waiting unacceptably long periods for elective surgery were limited to a small number of hospitals. Little and inconsistent support was found for associations of prolonged waiting with markers of capacity, independent sector activity, or need in the surgical specialties examined
Advantages of venous bypass during orthotopic transplantation of the liver.
Venous bypass restores normal hemodynamic physiology during the critical anhepatic phase of orthotopic transplantation of the liver. Its routine use in adults undergoing transplantation in Pittsburgh has resulted in lower operative blood losses, a lower frequency of postoperative renal failure, and a greater probability of survival for all but the highest risk patients. Because it allows for a longer anhepatic phase, the surgeon has the option of tailoring the native hepatectomy to the needs of the individual case, even to the point, in difficult cases, of obtaining most of the hemostasis after removal of the native liver, but before sewing in the donor organ. Selective use of bypass in children may offer similar advantages
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