5,008 research outputs found
Brane world models need low string scale
Models with large extra dimensions offer the possibility of the Planck scale being of order the electroweak scale, thus alleviating the gauge hierarchy problem. We show that these models suffer from a breakdown of unitarity at around three quarters of the low effective Planck scale. An obvious candidate to fix the unitarity problem is string theory. We therefore argue that it is necessary for the string scale to appear below the effective Planck scale and that the first signature of such models would be string resonances. We further translate experimental bounds on the string scale into bounds on the effective Planck scale
Who is in the transition gap? Transition from CAMHS to AMHS in the Republic of Ireland
Objective: The ITRACK study explored the process and predictors of transition between Child and Adolescent Mental Health Services (CAMHS) and Adult Mental Health Services (AMHS) in the Republic of Ireland. Method: Following ethical approval, clinicians in each of Ireland's four Health Service Executive (HSE) areas were contacted, informed about the study and invited to participate. Clinicians identified all cases who had reached the transition boundary (i.e. upper age limit for that CAMHS team ) between January and December 2010. Data were collected on clinical and socio-demographic details and factors that informed the decision to refer or not refer to AMHS and case notes were scrutinised to ascertain the extent of information exchanged between services during transition
Antitumour responses induced by short-term pretreatment with tumour cells.
The injection (s.c. or i.p.) of 10(6) live or lethally irradiated methylcholanthrene-induced fibrosarcoma cells into CBA/Ca mice one or 2 days before i.v. challenge with the same tumour inhibited the formation of artificial lung tumour metastases. In addition, it also frequently enhanced the cytostatic effect of peritoneal exudate cells on monolayers of the same tumour. The effects on lung tumour metastasis were not noted if X-irradiated tumour was injected i.v., or if s.c. administration was delayed until one day after i.v. challenge. Similar effects on tumour growth were also observed in C3Hf/Bu mice and (CBA/Ca x A/HeJ) F1 hybrids which were pretreated (s.c.) with tumour shortly before i.v. challenge with the same tumour. Further studies in CBA/Ca mice suggested that the protective effect was tumour-specific, for the growth of i.v. injected tumour was not significantly inhibited by pretreatement with a number of other MC-induced or spontaneous tumours from the same and different strains
Energy Spectra of Reactor Neutrinos at KamLAND
The upcoming reactor neutrino experiment, KamLAND, has the ability to explore
the Large Mixing Angle (LMA) solution to the solar neutrino problem. Here, we
investigate the precision to which KamLAND should be able to measure these
parameters, utilizing the distortion of the energy spectrum of reactor
neutrinos. Incomplete knowledge of the fuel composition of the reactors will
lead to some error on this measurement. We estimate the size of this effect.Comment: 7 pages, 7 figures. References added. Minor changes in wordin
TeV Strings and the Neutrino-Nucleon Cross Section at Ultra-high Energies
In scenarios with the fundamental unification scale at the TeV one expects
string excitations of the standard model fields at accessible energies. We
study the neutrino-nucleon cross section in these models. We show that duality
of the scattering amplitude forces the existence of a tower of massive
leptoquarks that mediate the process in the s-channel. Using the narrow-width
approximation we find a sum rule for the production rate of resonances with
different spin at each mass level. We show that these contributions can
increase substantially the standard model neutrino-nucleon cross section,
although seem insufficient in order to explain the cosmic ray events above the
GZK cutoff energy.Comment: 10 pages, 1 figure, version to appear in PR
Below-cost legislation: lessons from the Republic of Ireland
This paper traces the emergence, evolution, and demise of below cost legislation in the grocery industry in the republic of Ireland. The paper adds to our understanding of the legislation by adopting the view that, by using the net invoice price as its definition of cost, the legislation increased two streams of quasi-rents, first on suppliersâ brandeds and second on retailersâ own brands which acted to depress competitive forces and direct supplier-buyer negotiations to off-invoice discounts. Supplier generated quasi-rents financed discounts, and when coupled with retailersâ higher margins on their own brands, provided little incentive for a return to a price competitive environment. Two factors undermined this situation: the substitution of discountersâ products for suppliersâ brands as the discounters share of the market grew and the increase in cross border shopping. These had the combined effect of reducing the available quasi-rents earned in the Irish market resulting in the breakdown of the status quo and a return to price competition. Through its impact on negotiations, the legislation also introduced inefficiencies to both retailersâ and suppliers businesses representing additional waste that could have been more productively used to reduce consumer prices. The paper endorses the Governmentâs decision to rescind the order and remove an important constraint on both vertical and horizontal competition. Lessons from the Republic of Ireland suggest that the competitive response to the removal of below cost legislation, and reductions in prices, may take time and will depend on economic circumstances and a change in the prevailing norms of organizational behaviour and quasi-rent seeking opportunitie
Outcome Evaluation of a Pilot Study Using âNudgesâ
Background: Every school day, over 31 million U.S. children eat school lunches. Unfortunately, students often do not choose the healthy options in the school cafeteria. This paper describes outcome results of a pilot study using ânudgesâ to improve elementary school studentsâ fruits and vegetables selections.
Methods: A pilot study was conducted from January to May 2012, in six intervention schools and 2 control schools. A behavioral economics-based intervention was conducted using ânudgesâ or cues from the cafeteria (staff encouragement to select fruit and vegetables, food labels, âHarvest of the Monthâ posters), school (morning announcement messages, prompts regarding cafeteria food selections), and parents (school newsletter articles, parent listserve messages) to promote studentsâ selection of fruits and vegetables in the school cafeteria. The serving data from the point-of-service machine provided fruits and vegetables served per student per day.
Results:There were no significant differences in the number of servings of fruits and vegetables served per student per day, averaged over the study period. Process data revealed low implementation of the intervention components, which may partially explain results.
Conclusions: Low implementation of nudges led to non-significant results in this pilot study. However, providing environmental cues are important and warrant further research with full implementation. Starting 2012, the new meal pattern includes two vegetables and a fruit serving for lunch; and two fruit servings for breakfast. Minimal cost interventions should be explored to facilitate successful implementation of new school meal guidelines
GAP WORK project report: training for youth practitioners on tackling gender-related violence
This project sought to challenge gender-related violence against (and by) children and young people by developing training for practitioners who have everyday contact with general populations of children and young people (âyouth practitionersâ). Through improved knowledge and understanding practitioners can better identify and challenge sexist, sexualising, homophobic or controlling language and behaviour, and know when and how to refer children and young people to the most appropriate support services. This summary outlines the Project and our initial findings about the success of the four training programmes developed and piloted.Co-funded by the DAPHNE III programme of the EU
Development and evaluation of die materials for use in the growth of silicon ribbons by the inverted ribbon growth process, task 2, LSSA project
Silicon sessile drop experiments were performed on a variety of commercially available refractory carbides, nitrides, oxides, and borides to examine the potential of these materials for applications involving either direct contact with molten silicon or as substrates for CVD coatings in the fabrication of dies and crucibles for containing molten silicon. Simultaneous experiments were also conducted with CVD layers of SiC, Si3N4, and SiOxNy. Silicon nitride layers, deposited with NH3:SiH4 ratios ranging from 100:1 down to 5:1, were examined in sessile drop experiments to determine if the layers are degraded as a result of using lower reagent ratios. Preliminary experiments were undertaken on the stability of CVD Si3N4 near the melting point of silicon. Silicon ribbon segments were grown from vitreous carbon dies which had been coated with CVD Si3N4. Depending upon the purity of the die materials, ribbon resistivity values up to 40 Omega cm were obtained
It's Simplex! Disaggregating Measures to Improve Certified Robustness
Certified robustness circumvents the fragility of defences against
adversarial attacks, by endowing model predictions with guarantees of class
invariance for attacks up to a calculated size. While there is value in these
certifications, the techniques through which we assess their performance do not
present a proper accounting of their strengths and weaknesses, as their
analysis has eschewed consideration of performance over individual samples in
favour of aggregated measures. By considering the potential output space of
certified models, this work presents two distinct approaches to improve the
analysis of certification mechanisms, that allow for both dataset-independent
and dataset-dependent measures of certification performance. Embracing such a
perspective uncovers new certification approaches, which have the potential to
more than double the achievable radius of certification, relative to current
state-of-the-art. Empirical evaluation verifies that our new approach can
certify more samples at noise scale , with greater relative
improvements observed as the difficulty of the predictive task increases.Comment: IEEE S&P 2024, IEEE Security & Privacy 2024, 14 page
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