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Nucleate pool boiling is known for its exceptional heat transfer coefficients, with the use of cavities further improving bubble nucleation and heat transfer rate. To promote this heat transfer enhancement technique, a thorough understanding of the influence of cavity geometry on single bubble dynamics is required. The influence of depth and radius of cylindrical and conical cavities on the bubble dynamics of nucleate pool boiling of R1234yf were numerically investigated. The cavity radius was varied between 50 and 400 μm and the cavity depth between 100 and 1000 μm at a fixed heat flux of 28 kW/m2. It was found that the maximum equivalent diameter prior to departure was constant for cavities with radii smaller than 120 μm, while it increased linearly when increasing the cavity radius further. Cylindrical cavities exhibited high stability regardless of cavity radius or depth whereas conical cavities showed a decrease in vapor retention with increasing cavity angle. During the necking phase, the bubble interface became pinned at the cavity edge, depending on conical cavity angle, implying that smaller radii allowed for enhanced surface rewetting. Conical cavities could be considered as cylindrical cavities when the cavity angle was less than a quarter of the interface contact angle. When translating the single cavity findings to cavity array design, cylindrical cavities were recommended as they allowed for stable bubble behavior. For increased nucleation zones and rewetting, a sub-critical radius was recommended. Wider cavities were recommended for high superheat conditions as larger bubbles could enhance bubble growth. [ABSTRACT FROM AUTHOR]

Hatching/birthing asynchrony, when siblings emerge at least 12 h apart, is thought to be a significant driver of phenotypic variation and group cohesion that is commonly reported in invertebrates and birds, but rarely in squamates. We examined birthing asynchrony in African cordylid lizards (Cordylidae), a clade characterized by a wide range of sociality (a hypothesized evolutionary driver of this unique phenomenon). We monitored parturition from wild‐caught mothers from four species, which vary in their conspecific grouping behaviour. In two species, most litters were born asynchronously, over a maximum of 3–4 days respectively. The other two cordylids also exhibited asynchronous birth in all litters with more than one offspring, although this was not applicable for most litters because there was a prevalence of singleton litters. Our study uncovered birthing asynchrony in a novel taxonomic group, which suggests it evolved convergently in at least two social lizard clades from different continents. Furthermore, the function of birthing asynchrony and limiting litter size to a single offspring may be similar in social animals. We discuss the potential significance of this rare phenomenon in this disparate taxon, and compare it with other more well‐studied taxa, in order to guide future research directions. [ABSTRACT FROM AUTHOR]

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ctim.2007.07.005 Byline: M. Whiting (a), G. Leavey (b)(c), A. Scammell (a), S. Au (d), M. King (c) Keywords: Depression; Acupuncture; Sham control Abstract: To establish the feasibility of conducting a randomised controlled trial to evaluate the efficacy of acupuncture in the treatment of mild-to-moderate depression. Control group intervention, blinding of treatment, outcome measures and the acceptability of such a trial amongst participants were key factors to be addressed. The findings from this study will be used to determine the design of a phase III randomised controlled trial. Author Affiliation: (a) Wandsworth Primary Care Research Centre, Wandsworth PCT, London, UK (b) R&D Department, Barnet, Enfield and Haringey Mental Health Trust, London, UK (c) Department of Mental Health Sciences, University College London, London, UK (d) TCM Healthcare, Middlesex, UK

We present the Australian Square Kilometre Array Pathfinder (ASKAP) WALLABY pre-pilot observations of two 'dark' H  i sources (with H  i masses of a few times 108  |$\rm {M}_\odot$| and no known stellar counterpart) that reside within 363 kpc of NGC 1395, the most massive early-type galaxy in the Eridanus group of galaxies. We investigate whether these 'dark' H  i sources have resulted from past tidal interactions or whether they are an extreme class of low surface brightness galaxies. Our results suggest that both scenarios are possible, and not mutually exclusive. The two 'dark' H  i sources are compact, reside in relative isolation, and are more than 159 kpc away from their nearest H  i -rich galaxy neighbour. Regardless of origin, the H  i sizes and masses of both 'dark' H  i sources are consistent with the H  i size–mass relationship that is found in nearby low-mass galaxies, supporting the possibility that these H  i sources are an extreme class of low surface brightness galaxies. We identified three analogues of candidate primordial 'dark' H  i galaxies within the TNG100 cosmological, hydrodynamic simulation. All three model analogues are dark matter dominated, have assembled most of their mass 12–13 Gyr ago, and have not experienced much evolution until cluster infall 1–2 Gyr ago. Our WALLABY pre-pilot science results suggest that the upcoming large-area H  i surveys will have a significant impact on our understanding of low surface brightness galaxies and the physical processes that shape them. [ABSTRACT FROM AUTHOR]

We present neutral hydrogen (H  i) absorption spectra of the black hole candidate X-ray binary (XRB) MAXI J1348–630 using the Australian Square Kilometre Array Pathfinder (ASKAP) and MeerKAT. The ASKAP H  i spectrum shows a maximum negative radial velocity (with respect to the local standard of rest) of −31 ± 4 km s−1 for MAXI J1348–630, as compared to −50 ± 4 km s−1 for a stacked spectrum of several nearby extragalactic sources. This implies a most probable distance of |$2.2^{+0.5}_{-0.6}$|  kpc for MAXI J1348–630, and a strong upper limit of the tangent point distance at 5.3 ± 0.1 kpc. Our preferred distance implies that MAXI J1348–630 reached 17 ± 10  per cent of the Eddington luminosity at the peak of its outburst, and that the source transited from the soft to the hard X-ray spectral state at 2.5 ± 1.5  per cent of the Eddington luminosity. The MeerKAT H  i spectrum of MAXI J1348–630 (obtained from the older, low-resolution 4k mode) is consistent with the re-binned ASKAP spectrum, highlighting the potential of the eventual capabilities of MeerKAT for XRB spectral line studies. [ABSTRACT FROM AUTHOR]