The Cosmic Microwave Background in an Inhomogeneous Universe - why void models of dark energy are only weakly constrained by the CMB

The dimming of Type Ia supernovae could be the result of Hubble-scale inhomogeneity in the matter and spatial curvature, rather than signaling the presence of a dark energy component. A key challenge for such models is to fit the detailed spectrum of the cosmic microwave background (CMB). We present a detailed discussion of the small-scale CMB in an inhomogeneous universe, focusing on spherically symmetric `void' models. We allow for the dynamical effects of radiation while analyzing the problem, in contrast to other work which inadvertently fine tunes its spatial profile. This is a surprisingly important effect and we reach substantially different conclusions. Models which are open at CMB distances fit the CMB power spectrum without fine tuning; these models also fit the supernovae and local Hubble rate data which favours a high expansion rate. Asymptotically flat models may fit the CMB, but require some extra assumptions. We argue that a full treatment of the radiation in these models is necessary if we are to understand the correct constraints from the CMB, as well as other observations which rely on it, such as spectral distortions of the black body spectrum, the kinematic Sunyaev-Zeldovich effect or the Baryon Acoustic Oscillations.Comment: 23 pages with 14 figures. v2 has considerably extended discussion and analysis, but the basic results are unchanged. v3 is the final versio

Do primordial Lithium abundances imply there's no Dark Energy?

Explaining the well established observation that the expansion rate of the universe is apparently accelerating is one of the defining scientific problems of our age. Within the standard model of cosmology, the repulsive 'dark energy' supposedly responsible has no explanation at a fundamental level, despite many varied attempts. A further important dilemma in the standard model is the Lithium problem, which is the substantial mismatch between the theoretical prediction for 7-Li from Big Bang Nucleosynthesis and the value that we observe today. This observation is one of the very few we have from along our past worldline as opposed to our past lightcone. By releasing the untested assumption that the universe is homogeneous on very large scales, both apparent acceleration and the Lithium problem can be easily accounted for as different aspects of cosmic inhomogeneity, without causing problems for other cosmological phenomena such as the cosmic microwave background. We illustrate this in the context of a void model.Comment: 14 pages, 4 figures. v2: minor rearrangements in the text, comments and references expanded, results unchange

Experiments on subcooled flow boiling in I.C. engine-like conditions at low flow velocities

[EN] Subcooled boiling flow is specially attractive for engine cooling system design, as no essential changes in its architecture are required while it is still possible to take advantage of the highest rates of heat transfer associated with nucleate boiling, mostly at high engine loads. In this paper, experiments on subcooled boiling flow in representative temperature conditions were conducted with a usual engine coolant in the low velocity range, for which little information is available, even if it may be relevant when advanced thermal management strategies are used. The results were analyzed by comparison with a reference Chen-type model which provided reasonable results for relatively low wall temperatures, but with noticeable discrepancies at higher wall temperatures. Analysis of the deviations observed indicated a significant influence of the Prandtl number on the suppression factor, and the inclusion into the model of a first estimate of this effect produced a noticeable improvement in its results, thus suggesting that one such modified additive model may be useful for practical engine cooling applications. (C) 2013 Elsevier Inc. All rights reserved.This work has been supported by Ministerio de Ciencia e Innovacion through Grant TRA2010-16205. O. Cornejo is indebted to Senacyt Panama for their support.Torregrosa, AJ.; Broatch, A.; Olmeda, P.; Cornejo, O. (2014). Experiments on subcooled flow boiling in I.C. engine-like conditions at low flow velocities. Experimental Thermal and Fluid Science. 52:347-354. https://doi.org/10.1016/j.expthermflusci.2013.10.004S3473545

Structural and functional responses of benthic invertebrates to imidacloprid in outdoor stream mesocosms

Structural and functional responses of a benthic macroinvertebrate assemblage to pulses of the insecticide imidacloprid were assessed in outdoor stream mesocosms. Imidacloprid pulses reduced invertebrate abundance and community diversity in imidacloprid-dosed streams compared to control streams. These results correlated well with effects of imidacloprid on leaf litter decomposition and feeding rates of Pteronarcys comstocki, a stonefly, in artificial streams. Reductions in oxygen consumption of stoneflies exposed to imidacloprid were also observed in laboratory experiments. Our findings suggest that leaf litter degradation and single species responses can be sensitive ecotoxicological endpoints that can be used as early warning indicators and biomonitoring tools for pesticide contamination. The data generated illustrates the value of mesocosm experiments in environmental assessment and how the consideration of functional and structural endpoints of natural communities together with in situ single species bioassays can improve the evaluation and prediction of pesticide effects on stream ecosystems. (C) 2009 Elsevier Ltd. All rights reserved.Environment Canada’s Pesticide Science FundFC

Heterozygous COL17A1 variants are a frequent cause of amelogenesis imperfecta

Background Collagen XVII is most typically associated with human disease when biallelic COL17A1 variants (>230) cause junctional epidermolysis bullosa (JEB), a rare, genetically heterogeneous, mucocutaneous blistering disease with amelogenesis imperfecta (AI), a developmental enamel defect. Despite recognition that heterozygous carriers in JEB families can have AI, and that heterozygous COL17A1 variants also cause dominant corneal epithelial recurrent erosion dystrophy (ERED), the importance of heterozygous COL17A1 variants causing dominant non-syndromic AI is not widely recognised. Methods Probands from an AI cohort were screened by single molecule molecular inversion probes or targeted hybridisation capture (both a custom panel and whole exome sequencing) for COL17A1 variants. Patient phenotypes were assessed by clinical examination and analyses of affected teeth. Results Nineteen unrelated probands with isolated AI (no co-segregating features) had 17 heterozygous, potentially pathogenic COL17A1 variants, including missense, premature termination codons, frameshift and splice site variants in both the endo-domains and the ecto-domains of the protein. The AI phenotype was consistent with enamel of near normal thickness and variable focal hypoplasia with surface irregularities including pitting. Conclusion These results indicate that COL17A1 variants are a frequent cause of dominantly inherited non-syndromic AI. Comparison of variants implicated in AI and JEB identifies similarities in type and distribution, with five identified in both conditions, one of which may also cause ERED. Increased availability of genetic testing means that more individuals will receive reports of heterozygous COL17A1 variants. We propose that patients with isolated AI or ERED, due to COL17A1 variants, should be considered as potential carriers for JEB and counselled accordingly, reflecting the importance of multidisciplinary care

Mean strain effects and microstructural observation during in-vitro fatigue testing of NiTi

The non-linear nature of the superelastic phase transformation in NiTi means that conventional fatigue life theory is difficult to apply. The volume fraction of martensite/parent phase and its role in the fatigue mechanism is not understood. This paper considers the fatigue life of superelastic NiTi alloys when tested at 2Hz in Ringers solution. In agreement with other researchers [1] [2] it was found that low alternating strains but high mean strain values resulted in the longest fatigue lives. To support the mechanical testing data, optical and electron microscopy was used to investigate the mechanism of fatigue and the role of the NiTi microstructure

Letter from A.J. Moffat to Brigham Young, April 30, 1865

UteIn this letter, A. J. Moffat wrote to Brigham Young to discuss infractions committed by the Indians and the prospect for preventing future issues

Letter from Andrew J. Moffat to Brigham Young, July 23-26, 1865

UteIn this letter, A. J. Moffat wrote to Brigham Young to inform him of the affairs of his settlment including a recent murder committed by local Indians and other "Indian difficulties" they encountered