Links between atmospheric cloud radiative effects and tropical circulations

2021 Spring.Includes bibliographical references.Atmospheric cloud radiative effects (ACRE) quantify the radiative heating or cooling due to clouds within the atmosphere. In this study, a framework is developed with which to analyze the ways that ACRE impact large-scale circulations in humid and dry regions of the tropics. The frame-work is applied to a set of simulations from a global atmospheric model configured with uniform tropical sea surface temperatures, following the protocol of the Radiative Convective Equilibrium Model Intercomparison Project. It is found that humid regions export energy and import moisture, and that ACRE in extremely humid regions are strong enough to change the sign of the net radiation tendency. This net heating drives a feedback in which large-scale ascent moistens the troposphere by lifting latent energy from near the surface. Moisture at these higher levels then forms clouds which in turn reinforce the ACRE, continuing the process. The relevance of this feedback to the germinal study of Riehl and Malkus (1958) is discussed. Additionally, the analysis method reveals a simple relationship between cloud radiative effects and column relative humidity in the idealized model. The same relationship is also observed in cloud radiative effects calculated from satellite observations. This suggests a simple way to estimate the cloud radiative effect at the top of the atmosphere. The estimated cloud radiative effect may be useful in estimating the ACRE, which is harder to infer from measurements using previous methods. The estimation shows some skill at estimating the cloud radiative effect in humid regions across the tropics on time scales of one month or longer. The method is found to be extremely effective at estimating observed cloud radiative effects in the equatorial west Pacific. Weaknesses of the estimation method in relation to marine stratus clouds are discussed

Trouble shooting in colonies of experimental animals

In this paper a guide is offered for the investigation of problems in experimental animal colonies. It can not be an exhaustive list of all the potential areas to check. The process has to evolve as the checks are made and the trouble shooter has to adapt to each individual situation. But it is hoped that by discussing the important sections that are likely to involve most problem solving exercises those working in this field will feel more able to carry out their task

Standalone Track Reconstruction in the T-stations

An algorithm for fast and efficient tracking in the T-stations is describedtogether with its performance in the DC06 data challenge. An efficiency of94--$95~\%$ is achieved for tracks with momenta above 2~GeV for a ghost rate of $13~\%$

Updated Performance of the T-Seeding

Improvements to the performance of the track seeding since the start of the DC '06 data challenge are described. For tracks above 2~GeV an efficiency of $96.3~\%$ is achieved for a ghost rate of 8.1~\%. In addition, the expected performance of the algorithm during the 2007 pilot run is discussed

Using ordinary multiplication to do relativistic velocity addition

Relativistic addition of velocities in one dimension, though a mainstay of introductory physics, contributes much less physical insight than it could. For such calculations, we propose the use of velocity factors (two-way doppler factors). Velocities can easily, often by inspection, be turned into velocity factors, and vice versa. Velocity factors compose by ordinary multiplication. This simple device considerably extends the kinds of questions that can be asked and answered in an introductory course.Comment: 6 page

Back flushing on milking machine teat cups

THE possibility of replacing the dipping of teat cups between cows with a system of back flushing with water has been investigated for some time by different workers

Association between match activity variables, measures of fatigue and neuromuscular performance capacity following elite competitive soccer matches

The aim of the study was to assess the relationships between match activity variables, subsequent fatigue and neuromuscular performance capacity in elite soccer players. Subjects (n = 10) were professional soccer players participating in the English Championships. Match activity variables and markers of fatigue status were measured before and following two matches. Creatine kinase (CK) and muscle soreness were measured at baseline, immediately following, as well as 40 and 64 h post-match. Countermovement jump performance and perceived ratings of wellness were measured at baseline, then 40 and 64 h post-match. Relationships were shown between CK and the total number of accelerations and decelerations immediately (r = 0.63; large), 40 h (r = 0.45; moderate) and 64 h post-match (r = 0.35; moderate) (p < 0.05). Relationships between CK and total sprint distance (r = 0.39; moderate) and the number of sprints (r = 0.35; moderate) 40 h post-match (p < 0.05) were observed. Furthermore, relationships were shown between the perceived rating of wellness and number of accelerations 40 (r = 0.52; large) and 64 h (r = 0.40; moderate) post-match, sprint distance 40 h post-match (r = 0.40; moderate) and the total number of sprints 40 h post-match (r = 0.51; large) (p < 0.05). The quantification of match activity variables, particularly the total number of accelerations and decelerations and the number of sprints, provides insights into the fatigue status in elite soccer players 40 and 64 h post-match

Competitive market for multiple firms and economic crisis

The origin of economic crises is a key problem for economics. We present a model of long-run competitive markets to show that the multiplicity of behaviors in an economic system, over a long time scale, emerge as statistical regularities (perfectly competitive markets obey Bose-Einstein statistics and purely monopolistic-competitive markets obey Boltzmann statistics) and that how interaction among firms influences the evolutionary of competitive markets. It has been widely accepted that perfect competition is most efficient. Our study shows that the perfectly competitive system, as an extreme case of competitive markets, is most efficient but not stable, and gives rise to economic crises as society reaches full employment. In the economic crisis revealed by our model, many firms condense (collapse) into the lowest supply level (zero supply, namely bankruptcy status), in analogy to Bose-Einstein condensation. This curious phenomenon arises because perfect competition (homogeneous competitions) equals symmetric (indistinguishable) investment direction, a fact abhorred by nature. Therefore, we urge the promotion of monopolistic competition (heterogeneous competitions) rather than perfect competition. To provide early warning of economic crises, we introduce a resolving index of investment, which approaches zero in the run-up to an economic crisis. On the other hand, our model discloses, as a profound conclusion, that the technological level for a long-run social or economic system is proportional to the freedom (disorder) of this system; in other words, technology equals the entropy of system. As an application of this new concept, we give a possible answer to the Needham question: "Why was it that despite the immense achievements of traditional China it had been in Europe and not in China that the scientific and industrial revolutions occurred?"Comment: 17 pages; 3 figure

Animal-sediment interactions: the effect of ingestion and excretion by worms on mineralogy

International audienceBy controlled experiments that simulate marine depositional environments, it is shown that accelerated weathering and clay mineral authigenesis occur during the combined process of ingestion, digestion and excretion of fine-grained sediment by two species of annelid worms. Previously characterized synthetic mud was created using finely ground, low-grade metamorphic slate (temperature approximately 300°C) containing highly crystalline chlorite and muscovite. This was added to experiment and control tanks along with clean, wind-blown sand. Faecal casts were collected at regular intervals from the experimental tanks and, less frequently, from the control tanks. Over a period of many months the synthetic mud (slate) proved to be unchanged in the control tanks, but was significantly different in faecal casts from the experimental tanks that contained the worms Arenicola marina and Lumbricus terrestris. Chlorite was preferentially destroyed during digestion in the gut of A. marina. Both chlorite and muscovite underwent XRD peak broadening with a skew developing towards higher lattice spacing, characteristic of smectite formation. A neoformed Fe-Mg-rich clay mineral (possibly berthierine) and as-yet undefined clay minerals with very high d-spacing were detected in both A. marina and L. terrestris cast samples. We postulate that a combination of the low pH and bacteria-rich microenvironment in the guts of annelid worms may radically accelerate mineral dissolution and clay mineral precipitation processes during digestion. These results show that macrobiotic activity significantly accelerates weathering and mineral degradation as well as mineral authigenesis. The combined processes of sediment ingestion and digestion thus lead to early diagenetic growth of clay minerals in clastic sediments