Orientation cues for high-flying nocturnal insect migrants: do turbulence-induced temperature and velocity fluctuations indicate the mean wind flow?

Migratory insects flying at high altitude at night often show a degree of common alignment, sometimes with quite small angular dispersions around the mean. The observed orientation directions are often close to the downwind direction and this would seemingly be adaptive in that large insects could add their self-propelled speed to the wind speed, thus maximising their displacement in a given time. There are increasing indications that high-altitude orientation may be maintained by some intrinsic property of the wind rather than by visual perception of relative ground movement. Therefore, we first examined whether migrating insects could deduce the mean wind direction from the turbulent fluctuations in temperature. Within the atmospheric boundary-layer, temperature records show characteristic ramp-cliff structures, and insects flying downwind would move through these ramps whilst those flying crosswind would not. However, analysis of vertical-looking radar data on the common orientations of nocturnally migrating insects in the UK produced no evidence that the migrants actually use temperature ramps as orientation cues. This suggests that insects rely on turbulent velocity and acceleration cues, and refocuses attention on how these can be detected, especially as small-scale turbulence is usually held to be directionally invariant (isotropic). In the second part of the paper we present a theoretical analysis and simulations showing that velocity fluctuations and accelerations felt by an insect are predicted to be anisotropic even when the small-scale turbulence (measured at a fixed point or along the trajectory of a fluid-particle) is isotropic. Our results thus provide further evidence that insects do indeed use turbulent velocity and acceleration cues as indicators of the mean wind direction

A Comparison of the Accuracy and Reliability of the Wahoo KICKR and SRM Power Meter

The Wahoo KICKR cycling trainer is a new direct-drive electromagnetically braked bike-trainer that allows cyclists to use their own bicycles as ergometer. It is purported to provide ±3% accuracy in power, despite costing considerably less than other cycling ergometers. The purpose of this study was to assess the accuracy and reliability of several KICKR units against the more established SRM power meter using a first-principles based dynamic calibration rig (CALRIG).Five KICKRs and one SRM unit were assessed by a CALRIG-driven incremental test. Following a 15 min warm-up and ‘calibration’ as per manufacturer instructions, power was increased (starting at 50 W) by 50 W every 2 min up to 400 W. Each unit was tested twice non-consecutively, in random order. Data was recorded at 1 Hz, with the last 10 s of each stage being averaged for analysis. The mean error (%) and coefficient of determination (R2) versus CALRIG; as well as the change in mean error and Typical Error of Measurement (TEM) (expressed as a % coefficient of variation) between trials was calculated for each device.The mean error across all KICKR units was -1.5% (range: -3.1% to 0.0%) compared to -1.6% reported by the SRM. R2 >0.999 was found for all KICKR units and SRM compared to the CALRIG. The mean TEM for the KICKRs was 1.5% (range: 1.1% to 1.9%), whereas the SRM reported 0.7%. For test-retest reproducibility, two KICKRs had statistically significant changes in mean error, with an average 1.3% change across all KICKRs. Comparatively, the SRM reported a 0.4% change between trials. The Wahoo KICKR trainer measures power to a similar level of accuracy to the more reputable SRM power meter during an incremental exercise test. Although not as reproducible, the KICKR still demonstrates an acceptable level of reliability for assessing cycling performance

Two-Particle Correlations in Relativistic Heavy-Ion Collisions

Two-particle momentum correlations between pairs of identical particles produced in relativistic heavy-ion reactions can be analyzed to extract the space-time structure of the collision fireball. We review recent progress in the application of this method, based on newly developed theoretical tools and new high-quality data from heavy-ion collision experiments. Implications for our understanding of the collision dynamics and for the search for the quark-gluon plasma are discussed.Comment: 44 pages, LaTeX, 11 Figures, uses special style files (included), prepared for Ann. Rev. Nucl. Part. Sci. 49 (1999). Error in Chapt. 1 corrected and a few references adde

Reassessing China’s Higher Education Development: A Focus on Academic Culture

During the past three and a half decades, China has been progressing in higher education in a surprisingly dramatic manner, evidenced especially by scientific publications and sheer numbers of graduates. Such a fact has national, regional and global implications. China’s higher education development and its future directions are now placed highly on the research agendas of many from various parts of the world. Unlike the general acknowledgment of China’s achievements, assessment of the future development of China’s higher education is wide open to question. To some, Chinese universities are on a trajectory to become “world-class” and China’s high-fliers challenge Western supremacy. To others, China’s notion of “world-class” status has been largely imitative. Pumping resources into universities will only lead to diminishing returns as Chinese culture and practices will act as a brake to the pursuit of academic excellence. An increasing deal of attention has been paid to where China will be located in a global higher education landscape and in what shape. Based on the author’s long-standing professional observation and recent empirical studies, this article assesses China’s higher education development, with a particular focus on the challenges brought forward by academic culture. It interrogates China’s pride of the idea that Chinese universities are not willing to assume that Western models define excellence, and asks how far Chinese universities could move within their current development model.postprin

An Integrated Approach Providing Scientific and Policy-Relevant Insights for South-West Bangladesh

Bangladesh is identified as an impact hotspot for sea-level rise in multiple studies. However, a range of other factors must be considered including catchment management, socio-economic development and governance quality, as well as delta plain biophysical processes. Taking an integrated assessment approach highlights that to 2050 future changes are more sensitive to human choice/policy intervention than climate change, ecosystem services diminish as a proportion of the economy with time, continuing historic trends and significant poverty persists for some households. Hence under favourable policy decisions, development could transform Bangladesh by 2050 making it less vulnerable to longer-term climate change and subsidence. Beyond 2050, the threats of climate change are much larger, requiring strategic adaptation responses and policy changes that must be initiated now

The Complete Star Formation History of the Universe

The determination of the star-formation history of the Universe is a key goal of modern cosmology, as it is crucial to our understanding of how structure in the Universe forms and evolves. A picture has built up over recent years, piece-by-piece, by observing young stars in distant galaxies at different times in the past. These studies indicated that the stellar birthrate peaked some 8 billion years ago, and then declined by a factor of around ten to its present value. Here we report on a new study which obtains the complete star formation history by analysing the fossil record of the stellar populations of 96545 nearby galaxies. Broadly, our results support those derived from high-redshift galaxies elsewhere in the Universe. We find, however, that the peak of star formation was more recent - around 5 billion years ago. Our study also shows that the bigger the stellar mass of the galaxy, the earlier the stars were formed. This striking result indicates a very different formation history for high- and low-mass formation.Comment: Accepted by Nature. Press embargo until publishe

Can a falling tree make a noise in two forests at the same time?

It is a commonplace to claim that quantum mechanics supports the old idea that a tree falling in a forest makes no sound unless there is a listener present. In fact, this conclusion is far from obvious. Furthermore, if a tunnelling particle is observed in the barrier region, it collapses to a state in which it is no longer tunnelling. Does this imply that while tunnelling, the particle can not have any physical effects? I argue that this is not the case, and moreover, speculate that it may be possible for a particle to have effects on two spacelike separate apparatuses simultaneously. I discuss the measurable consequences of such a feat, and speculate about possible statistical tests which could distinguish this view of quantum mechanics from a ``corpuscular'' one. Brief remarks are made about an experiment underway at Toronto to investigate these issues.Comment: 9 pp, Latex, 3 figs, to appear in Proc. Obsc. Unr. Conf.; Fig 2 postscript repaired on 26.10.9

Conjugated bile acids attenuate allergen-induced airway inflammation and hyperresposiveness by inhibiting UPR transducers

© 2019 American Society for Clinical Investigation. Conjugated bile acids (CBAs), such as tauroursodeoxycholic acid (TUDCA), are known to resolve the inflammatory and unfolded protein response (UPR) in inflammatory diseases, such as asthma. Whether CBAs exert their beneficial effects on allergic airway responses via 1 arm or several arms of the UPR, or alternatively through the signaling pathways for conserved bile acid receptor, remains largely unknown. We used a house dust mite-induced (HDM-induced) murine model of asthma to evaluate and compare the effects of 5 CBAs and 1 unconjugated bile acid in attenuating allergen-induced UPR and airway responses. Expression of UPRassociated transcripts was assessed in airway brushings from human patients with asthma and healthy subjects. Here we show that CBAs, such as alanyl β-muricholic acid (AβM) and TUDCA, significantly decreased inflammatory, immune, and cytokine responses; mucus metaplasia; and airway hyperresponsiveness, as compared with other CBAs in a model of allergic airway disease. CBAs predominantly bind to activating transcription factor 6α (ATF6α) compared with the other canonical transducers of the UPR, subsequently decreasing allergen-induced UPR activation and resolving allergic airway disease, without significant activation of the bile acid receptors. TUDCA and AβM also attenuated other HDM-induced ER stress markers in the lungs of allergic mice. Quantitative mRNA analysis of airway epithelial brushings from human subjects demonstrated that several ATF6α-related transcripts were significantly upregulated in patients with asthma compared with healthy subjects. Collectively, these results demonstrate that CBA-based therapy potently inhibits the allergen-induced UPR and allergic airway disease in mice via preferential binding of the canonical transducer of the UPR, ATF6α. These results potentially suggest a novel avenue to treat allergic asthma using select CBAs

‘Free’ inhibin α subunit is expressed by bovine ovarian theca cells and its knockdown suppresses androgen production

Inhibins are ovarian dimeric glycoprotein hormones that suppress pituitary FSH production. They are synthesised by follicular granulosa cells as α plus βA/βB subunits (encoded by INHA, INHBA, INHBB, respectively). Inhibin concentrations are high in follicular fluid (FF) which is also abundant in ‘free’ α subunit, presumed to be of granulosal origin, but its role(s) remains obscure. Here, we report the unexpected finding that bovine theca cells show abundant INHA expression and ‘free’ inhibin α production. Thus, theca cells may contribute significantly to the inhibin α content of FF and peripheral blood. In vitro, knockdown of thecal INHA inhibited INSL3 and CYP17A1 expression and androgen production while INSL3 knockdown reduced INHA and inhibin α secretion. These findings suggest a positive role of thecal inhibin α on androgen production. However, exogenous inhibin α did not raise androgen production. We hypothesised that inhibin α may modulate the opposing effects of BMP and inhibin on androgen production. However, this was not supported experimentally. Furthermore, neither circulating nor intrafollicular androgen concentrations differed between control and inhibin α-immunized heifers, casting further doubt on thecal inhibin α subunit having a significant role in modulating androgen production. Role(s), if any, played by thecal inhibin α remain elusive