A new intrinsic thermal parameter for enzymes reveals true temperature optima

Two established thermal properties of enzymes are the Arrhenius activation energy and thermal stability. Arising from anomalies found in the variation of enzyme activity with temperature, a comparison has been made of experimental data for the activity and stability properties of five different enzymes with theoretical models. The results provide evidence for a new and fundamental third thermal parameter of enzymes, Teq, arising from a subsecond timescale-reversible temperature-dependent equilibrium between the active enzyme and an inactive (or less active) form. Thus, at temperatures above its optimum, the decrease in enzyme activity arising from the temperature-dependent shift in this equilibrium is up to two orders of magnitude greater than what occurs through thermal denaturation. This parameter has important implications for our understanding of the connection between catalytic activity and thermostability and of the effect of temperature on enzyme reactions within the cell. Unlike the Arrhenius activation energy, which is unaffected by the source (“evolved”) temperature of the enzyme, and enzyme stability, which is not necessarily related to activity, Teq is central to the physiological adaptation of an enzyme to its environmental temperature and links the molecular, physiological, and environmental aspects of the adaptation of life to temperature in a way that has not been described previously. We may therefore expect the effect of evolution on Teq with respect to enzyme temperature/activity effects to be more important than on thermal stability. Teq is also an important parameter to consider when engineering enzymes to modify their thermal properties by both rational design and by directed enzyme evolution

Gaelic Language Plan Implementation Assessment Cycle 6 : Final Report to Bòrd na Gàidhlig

The Gaelic Language Plans (GLPs) of fourteen public organisations were analysed by a group of impartial researchers from UWS, GCU, Heriot Watt, and Iaith. This exercise was Cycle 6 in a series of GLP assessments. Each GLP was textually analysed to list all core commitments and targets set in the areas of Status, Corpus, Acquisition and Usage planning. Fidelity assessments then took place of these commitments/targets using FOI requests, ‘secret shopping’, interview and a survey that included employees and staff. Each organisation was provided a comprehensive assessment report for the implementation of their GLP, culminating in recommendations to them and to the Bòrd. This report provides a summary report for Cycle 6’s assessments. It provides some reference to individual organisations implementation efforts, but for detailed information relating to individual organisations, individual reports should be consulted. This summary report highlights transversal issues arising from the assessment process

Mpemba Effect, Shechtman's Quasicrystals and Students' Exploring Activities

In the 1960s, Tanzanian student Erasto Mpemba and his teacher published an article with the title "Cool" in the journal Physics Education (Mpemba, E. B. - Osborne, D. G.: Cool?. In: Physics Education, vol.4, 1969, pp. 172-175.). In this article they claimed that hot water freezes faster than cold water. The article raised not only a wave of discussions, and other articles about this topic, but also a whole series of new experiments, which should verify this apparent thermodynamic absurdity and find an adequate explanation. Here we give a review with references to explanations and we bring some proposals for experimental student work in this area. We introduce Mpemba Effect not only as a paradoxical physics phenomenon, but we shall present a strong educational message that the Mpemba story brings to the teachers and their students. This message also creates a bridge between this phenomenon and the discovery for which the 2011 Nobel Prize in Chemistry was awarded. It leads to critical adoption of traditional knowledge and encourages resilience in investigative exploration of new things

Pre-Impoundment Fish Stock Assessment of the Black Volta: A Contribution to Fisheries Management of Bui Reservoir in Ghana

A length-based fish stock assessment of the Black Volta River in Ghana was undertaken prior to its damming at Bui in 2011. The approach involved estimation of the population parameters and exploitation rates of dominant fish stocks using TropFish R. The targeted species were: Alestes baremoze, Hydrocynus forskalii, Hemisynodontis membranaceus and Labeo coubie. The estimated asymptotic length (L∞) ranged from 30.8 – 48.2 cm standard length (SL) with derived longevity of 11 – 27 years for the assessed species. The estimated growth coefficient (K) value ranged from 0.10 – 0.25 yr-1 which suggested slow growth rates. The estimated length at first capture (Lc50) was lower than the length at first maturity (Lm50) for all the assessed fish species which suggests the presence of recruitment overfishing within the fish stocks. The total mortality rate (Z) was relatively high ranging between 0.51 and 1.34 yr-1 suggesting that the stocks were over-exploited during the pre-impoundment period. The exploitation rate (E) for the assessed fish species were lower than the maximum exploitation rate (Emax) which indicates that the species are far from collapse. These estimates are baseline scientific information for designing a Fisheries Management Plan for the Bui reservoir. Meanwhile, alternative livelihood and employment opportunities such as cage fish culture are to be explored to reduce the fishing pressure on the reservoir

Non-intersecting leaf insertion algorithm for tree structure models

We present an algorithm and an implementation to insert broadleaves or needleleaves to a quantitative structure model according to an arbitrary distribution, and a data structure to store the required information efficiently. A structure model contains the geometry and branching structure of a tree. The purpose of the work is to offer a tool for making more realistic simulations with tree models with leaves, particularly for tree models developed from terrestrial laser scan (TLS) measurements. We demonstrate leaf insertion using cylinder-based structure models, but the associated software implementation is written in a way that enables the easy use of other types of structure models. Distributions controlling leaf location, size and angles as well as the shape of individual leaves are user-definable, allowing any type of distribution. The leaf generation process consist of two stages, the first of which generates individual leaf geometry following the input distributions, while in the other stage intersections are prevented by doing transformations when required. Initial testing was carried out on English oak trees to demonstrate the approach and to assess the required computational resources. Depending on the size and complexity of the tree, leaf generation takes between 6 and 18 minutes. Various leaf area density distributions were defined, and the resulting leaf covers were compared to manual leaf harvesting measurements. The results are not conclusive, but they show great potential for the method. In the future, if our method is demonstrated to work well for TLS data from multiple tree types, the approach is likely to be very useful for 3D structure and radiative transfer simulation applications, including remote sensing, ecology and forestry, among others

Impacto de las actividades de construcción de puertos en la estructura, composición y diversidad de la población de peces: estudio de caso de Tema, Ghana

Ports offer economic progress to many coastal developing countries. In view of the economic importance, the rising demand for maritime benefits requires the expansion of existing ports. However, marine ecosystems may become vulnerable to negative impact from the construction of these maritime structures. Therefore, the aim of the study was to establish the impact of Tema port expansion on the diversity and population structure of fish species. Data were collected quarterly from June 2018 to November 2021 through trawling fishing activities off the coast of Greater Accra, Ghana, and subsequently analysed using Primer 6 software. Sampling locations along the coast of Greater Accra included Vernon Bank (VNB), Disposal area (DSA) and Offshore Sakumono (OSK). The increased and reduced number of species at VNB and DSA, respectively, could be alluded to dredging and disposal of dredged spoils. Diversity indices at OSK site was higher than those observed in disturbed areas due to the absence of impact in this control area. Thus, it is recommended to conduct further studies on the assemblage of invasive species that migrated to the VNB during dredging activities, since these species can have severe economic impact on fishing activities of artisanal fishermen, especially at the local level.Los puertos ofrecen progreso económico a muchos países costeros en desarrollo. En vista de la importancia económica, la creciente demanda de beneficios marítimos requiere la ampliación de los puertos existentes. Sin embargo, los ecosistemas marinos pueden volverse vulnerables al impacto negativo de la construcción de estas estructuras marítimas. Por lo tanto, el objetivo del estudio fue establecer el impacto de la expansión del puerto de Tema sobre la diversidad y estructura de la población de peces. Los datos se recopilaron trimestralmente desde junio de 2018 hasta noviembre de 2021 mediante actividades de pesca de arrastre fren-te a la costa del Gran Accra, Ghana. Los mismos se analizaron utilizando el software Primer 6. Los lugares de muestreo a lo largo de la costa del Gran Accra incluyeron Vernon Bank (VNB), Disposal area (DSA) y Offshore Sakumono (OSK). El mayor y menor número de especies en VNB y DSA, respectivamente, podría deberse al dragado y disposición de los escombros removidos. Los índices de diversidad en el sitio OSK fueron más altos que los observados en áreas perturbadas debido a la ausencia de impacto en esta área de control. Por lo tanto, se recomienda realizar más estudios sobre las asociaciones de especies invasoras que migraron al VNB durante las actividades de dragado, ya que estas especies pueden tener severos impactos económicos en la actividad pesquera de los pescadores artesanales, especialmente a nivel local

Summary [January 1978]

This brief provides a summary of the world, UK and Scottish economic outlook. The upward movement in the Scotland/UK unemployment relative over the past few quarters is unlikely to portend a return to the poor relative performance of the Scottish economy which occurred in the early nineteen sixties. Nevertheless the outlook for the Scottish economy in 1978 is not very encouraging

Review of the quarter's economic trends [January 1977]

There is now ample evidence that the pace of recovery in the major economies slackened during 1976. Published statistics, however, are as yet inadequate to document the full extent of the slowdown or to assert that it was a transient phenomenon. Available evidence would suggest that the growth in the major economies in 1977 may be somewhat slower than had earlier been forecast, and that in the short run further reductions in unemployment and inflation rates may be very difficult to achieve. Several threads may be drawn together in an attempt to justify this interpretation of likely future developments

Econometric forecasts for Scotland

In the first issue (July 1975) of the Fraser of Allander Institute Quarterly Economic Commentary, the special article, by Professor J McGilvray, reviewed the problems associated with constructing regional econometric models to forecast key economic variables. Since that time, a number of forecasts for the Scottish economy have been made in the main text or in special articles of the Quarterly Commentary. Many of these have been underpinned by forecasting relationships which have been estimated for particular sectors of the economy. Up to now we have been unable to produce a set of relationships which could genuinely be described as a 'model' of the Scottish economy. The reason for this is simple, but illustrative of the type of problem discussed by Professor McGilvray. To understand it one must be acquainted with the fundamental differences which exist between national and regional economic models