533 research outputs found
Evaluation of a sub-kilometre NWP system in an Arctic fjord-valley system in winter
Terrain challenges the prediction of near-surface atmospheric conditions, even in kilometre-scale numerical
weather prediction (NWP) models. In this study, the ALADIN-HIRLAM NWP system with 0.5 km
horizontal grid spacing and an increased number of vertical levels is compared to the 2.5-km model system
similar to the currently operational NWP system at the Norwegian Meteorological Institute. The impact of
the increased resolution on the forecasts’ ability to represent boundary-layer processes is investigated for the
period from 12 to 16 February 2018 in an Arctic fjord-valley system in the Svalbard archipelago. Model
simulations are compared to a wide range of observations conducted during a field campaign. The model
configuration with sub-kilometre grid spacing improves both the spatial structure and overall verification
scores for the near-surface temperature and wind forecasts compared to the 2.5-km experiment. The subkilometre experiment successfully captures the wind channelling through the valley and the temperature field
associated with it. In a situation of a cold-air pool development, the sub-kilometre experiment has a
particularly high near-surface temperature bias at low elevations. The use of measurement campaign data,
however, reveals some encouraging results, e.g. the sub-kilometre system has a more realistic vertical profile
of temperature and wind speed, and the surface temperature sensitivity to the net surface energy is closer to
the observations. This work demonstrates the potential of sub-kilometre NWP systems for forecasting
weather in complex Arctic terrain, and also suggests that the increase in resolution needs to be accompanied
with further development of other parts of the model system
Gravitationally lensed QSOs in the ISSIS/WSO-UV era
Gravitationally lensed QSOs (GLQs) at redshift z = 1-2 play a key role in
understanding the cosmic evolution of the innermost parts of active galaxies
(black holes, accretion disks, coronas and internal jets), as well as the
structure of galaxies at intermediate redshifts. With respect to studies of
normal QSOs, GLQ programmes have several advantages. For example, a monitoring
of GLQs may lead to unambiguous detections of intrinsic and extrinsic
variations. Both kinds of variations can be used to discuss central engines in
distant QSOs, and mass distributions and compositions of lensing galaxies. In
this context, UV data are of particular interest, since they correspond to
emissions from the immediate surroundings of the supermassive black hole. We
describe some observation strategies to analyse optically bright GLQs at z of
about 1.5, using ISSIS (CfS) on board World Space Observatory-Ultraviolet.Comment: 7 pages, 4 figures, Accepted for publication in Astrophysics & Space
Scienc
The new IOC and IAAF policies on female eligibility: old Emperor, new clothes?
The Caster Semenya debacle touched off by the 2009 Berlin World Athletics Championships resulted finally in IOC and IAAF abandonment of sex testing, which gave way to procedures that make female competition eligibility dependent upon the level of serum testosterone, which must be below the male range or instrumentally countered by androgen resistance. We argue that the new policy is unsustainable because (i) the testosterone-performance connection it posits is uncompelling; (ii) testosterone-induced female advantage is not ipso facto unfair advantage; (iii) the new policy reflects the gender policing impulses endemic to sport as well as the broader cultural impulses to monstrify women and to doctor women who have nothing wrong with them; (iv) female–male performance disparities are not the only reason for sex-segregated sport, but co-exist with respectable cultural and practical reasons, which (v) provide a powerful case for allowing athletes to compete in the sex category congruent with their gender identity
Catalytically inactive carbonic anhydrase-related proteins enhance the transport of lactate by MCT1
Carbonic anhydrases (CA) catalyze the reversible hydration of CO2 to protons and bicarbonate and thereby play a fundamental role in the epithelial acid/base transport mechanisms serving fluid secretion and absorption for whole‐body acid/base regulation. The three carbonic anhydrase‐related proteins (CARPs) VIII, X, and XI, however, are catalytically inactive. Previous work has shown that some CA isoforms noncatalytically enhance lactate transport through various monocarboxylate transporters (MCT). Therefore, we examined whether the catalytically inactive CARPs play a role in lactate transport. Here, we report that CARP VIII, X, and XI enhance transport activity of the MCT MCT1 when coexpressed in Xenopus oocytes, as evidenced by the rate of rise in intracellular H+ concentration detected using ion‐sensitive microelectrodes. Based on previous studies, we suggest that CARPs may function as a ‘proton antenna’ for MCT1, to drive proton‐coupled lactate transport across the cell membrane
Challenging sex segregation: A philosophical evaluation of the football association’s rules on mixed football
The Football Association (FA) has been under pressure to allow girls to play in mixed teams since 1978, following 12-year old Theresa Bennett’s application to play with boys in a local league. In 1991, over a decade after Bennett’s legal challenge, the FA agreed to remove its ban on mixed football and introduced Rule C4 in order to permit males and females to play together in competitive matches under the age of 11. More recently, following a campaign by parents, coaches, local Members of Parliament and the Women’s Sport Foundation, the FA agreed to trial mixed football for the under-12 to under-15 age categories in order to establish, among other things, the risk of injury to players in sex-integrated competitions. A series of exponential changes ensued: between 2010 and 2014, the age at which mixed football was permitted increased from U11 to U16. In 2015, the FA announced the decision to raise the age limit on mixed football from U16 to U18 for the forthcoming 2015–2016 season. We critically examine the reasons given by the FA for enforcing segregated participation beyond the age of 18, namely that males have an unfair advantage and that females face an unacceptable risk of injury. We also discuss the argument that removing the ban might harm the women’s game. In conclusion, we suggest that the FA ought to abandon the ban on mixed football over the age of 18
Cosmological distance indicators
We review three distance measurement techniques beyond the local universe:
(1) gravitational lens time delays, (2) baryon acoustic oscillation (BAO), and
(3) HI intensity mapping. We describe the principles and theory behind each
method, the ingredients needed for measuring such distances, the current
observational results, and future prospects. Time delays from strongly lensed
quasars currently provide constraints on with < 4% uncertainty, and with
1% within reach from ongoing surveys and efforts. Recent exciting discoveries
of strongly lensed supernovae hold great promise for time-delay cosmography.
BAO features have been detected in redshift surveys up to z <~ 0.8 with
galaxies and z ~ 2 with Ly- forest, providing precise distance
measurements and with < 2% uncertainty in flat CDM. Future BAO
surveys will probe the distance scale with percent-level precision. HI
intensity mapping has great potential to map BAO distances at z ~ 0.8 and
beyond with precisions of a few percent. The next years ahead will be exciting
as various cosmological probes reach 1% uncertainty in determining , to
assess the current tension in measurements that could indicate new
physics.Comment: Review article accepted for publication in Space Science Reviews
(Springer), 45 pages, 10 figures. Chapter of a special collection resulting
from the May 2016 ISSI-BJ workshop on Astronomical Distance Determination in
the Space Ag
Toward an internally consistent astronomical distance scale
Accurate astronomical distance determination is crucial for all fields in
astrophysics, from Galactic to cosmological scales. Despite, or perhaps because
of, significant efforts to determine accurate distances, using a wide range of
methods, tracers, and techniques, an internally consistent astronomical
distance framework has not yet been established. We review current efforts to
homogenize the Local Group's distance framework, with particular emphasis on
the potential of RR Lyrae stars as distance indicators, and attempt to extend
this in an internally consistent manner to cosmological distances. Calibration
based on Type Ia supernovae and distance determinations based on gravitational
lensing represent particularly promising approaches. We provide a positive
outlook to improvements to the status quo expected from future surveys,
missions, and facilities. Astronomical distance determination has clearly
reached maturity and near-consistency.Comment: Review article, 59 pages (4 figures); Space Science Reviews, in press
(chapter 8 of a special collection resulting from the May 2016 ISSI-BJ
workshop on Astronomical Distance Determination in the Space Age
Forward pi^0 Production and Associated Transverse Energy Flow in Deep-Inelastic Scattering at HERA
Deep-inelastic positron-proton interactions at low values of Bjorken-x down
to x \approx 4.10^-5 which give rise to high transverse momentum pi^0 mesons
are studied with the H1 experiment at HERA. The inclusive cross section for
pi^0 mesons produced at small angles with respect to the proton remnant (the
forward region) is presented as a function of the transverse momentum and
energy of the pi^0 and of the four-momentum transfer Q^2 and Bjorken-x.
Measurements are also presented of the transverse energy flow in events
containing a forward pi^0 meson. Hadronic final state calculations based on QCD
models implementing different parton evolution schemes are confronted with the
data.Comment: 27 pages, 8 figures and 3 table
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