Studies on Leaf Blight Disease of Sissoo (Dalbergia sissoo Roxb.) in Bangladesh

The outbreak of leaf blight disease in sissoo (Dalbergia sissoo Roxb.) was detected in different plantation areas of Sylhet, Bangladesh, during surveys conducted in November 2019. Isolates were consistently recovered from the necrotic region of the blight infected leaves. Isolates grown on potato-dextrose-agar (PDA) showed greyish-white cottony mycelia with a concentric zone of orange conidial masses. Average conidia length and width ranging from 13.5-17.7 µm and 3.5-5.3 µm, respectively. In the pathogenicity test, the pathogen was able to cause infection on detached healthy leaves and spots developed were similar to those observed on the leaves affected in nature. However, the pathogen produced disease symptoms in wounded leaves but did not produce any symptoms on the non-wound ones. Findings also suggested that the pathogen was equally virulent to three-leaf grades (young, middle and mature-aged). Based on the above morphological features, the pathogen was identified as Colletotrichum sp. Molecular identification is needed to determine the pathogen up to species. The observation of the pathogen causing leaf blight disease of sissoo in Bangladesh has severe implications regarding the management of plantations and nurseries. More surveys are needed to determine the distribution and extent of damage caused by the pathogen in other regions.

STUDY OF THE CHEMICAL COMPOSITION OF VOLUME-SURFACE CONCENTRIC-ZONE COLOR SPECTRA IN ZOLOCERAMIC MATERIALS

The article presents the results of a study of the chemical composition of new volumetric-surface concentric-zonal color spectra in ash-ceramic materials associated with a well-known phenomenon in the scientific world called "Kulbek's Rings". One of the variants of the "Kulbek's Ring" was used as an object of research, which takes place in samples made on the basis of ash generated from the combustion of Ekibastuz coal. The experimental studies were carried out by the method of X-ray fluorescence (XRF) analysis on a special laboratory setup. Concentric-zonal color spectra in the phenomenon of "Kulbek's Ring" in ash-ceramic cylindrical samples are located strictly symmetrically relative to the center of the surface. The research focused on this provision. An analysis of the XRF spectra showed that symmetry, i.e., uniformity, is observed concentrically located in the color bands of the sample

Updating Ravenstein: Internal Migration as a Driver of Regional Population Change in the Wider South East of England

Key among Ravenstein’s “laws”, derived from extensive analysis of mid-19th century migration patterns in the British Isles, are that the majority of migrants go only a short distance and that migration proceeds stepwise as a sequence of localised population shifts towards the principal centres of commerce and industry. This paper tests these two laws in the 21st century context of counterurbanisation by reference to migration taking place within the Wider South East (WSE) of England, being the region dominated by deconcentration pressures emanating from London. It comprises two sets of empirical analyses using migration data for the period 2001-2016. Firstly, these data are aggregated to a set of broadly concentric rings around this core and analysed to reveal how much of the net outward shifts of population produced by this migration arises from net movement taking place between adjacent rings as a type of cascade as opposed to leapfrogging directly from the core into a non-adjacent ring. Cascading is found to predominate at this scale, confirming the continued importance of shorter-distance moving. Secondly, the migration data are rendered into a Travel to Work Area (TTWA) framework to examine the extent to which these subdivisions of the WSE perform a type of entrepôt role in helping to shift population outwards from London. Drawing on Ravenstein’s concepts of counties of “transfer” and “absorption”, two measures are developed for revealing how the net inflow to a particular TTWA from rings closer to the core compares numerically with the net outflow from that TTWA to the rings further away from it. The derived transfer and absorption rates are then used to classify the TTWAs into four groups according to whether their scores on each are above or below average. It is found that a TTWA’s role varies according to two main dimensions: the concentric zone to which it belongs and the radial sector out of London in which it is located, notably whether the sector has a coastal or landward border. * This article belongs to a special issue on “Internal Migration as a Driver of Regional Population Change in Europe: Updating Ravenstein”.

From School Benches Straight to Retirement? Similarities and Differences in the Shopping Behaviour of Teenagers and Seniors in Bratislava, Slovakia

The shopping behaviours of teenagers in shopping centres in Bratislava (Slovakia) is compared to those of seniors in this paper. The analysis focuses on the perception of shopping centres by teenagers and seniors in the context of time (shopping frequency), social (with whom they shop) and financial (amount of money spent) factors. The survey was conducted on random samples of 504 teenagers and 431 seniors. To test the hypotheses, group means were evaluated (Analysis of Variance models). When assessing the spatial aspects of teenagers’ and seniors’ shopping behaviours, a concentric zone approach was used. It can be concluded that Bratislava teenagers are not as sensitive consumers as seniors in the context of the variables assessed in the survey. Teenagers perceive shopping centres as a normal part of their consumption behaviours. Seniors perceive the shopping centres less positively and they spent a shorter time there. Also, in the case of seniors, the frequency of their visits to shopping centres increased in the context of their positive perceptions.

Primary Outcomes of Accelerated Epithelium-Off Corneal Cross-Linking in Progressive Keratoconus in Children: A 1-Year Prospective Study

Purpose. To evaluate corneal transparency following accelerated collagen cross-linking (ACXL) in pediatric keratoconus.Design. A prospective interventional case series.Methods. This study included 47 eyes (25 patients), aged 9–14 years, with documented progressive keratoconus. After applying 0.1% riboflavin drops, ACXL was performed. Assessment included corrected distance visual acuity (CDVA), uncorrected visual acuity (UCVA), corneal haze, and corneal densitometry in grayscale units (GSU).Result. The mean baseline and corneal densitometry peaked at 3 months post-ACXL while central and posterior densitometry showed a statistically significant increase (P<0.05) and peaked at 8 months postoperatively. By 12 months, densitometry in all corneal layers (P≥0.99) and concentric zones (P≥0.97) reached near baseline values. Slit-lamp graded haze peaked at 1 month to 1.82 ± 0.65 (P<0.05) and declined to near baseline at 12 months (0.39 ± 0.58). There was a statistically significant increase in the mean UCVA and CDVA at 12 months.Conclusion. Total and anterior corneal densitometry peaked after 3 months, while central and posterior densitometry peaked after 8 months. Maximum haze was at 1 month post-ACXL. All corneal layers, concentric zone densitometry and haze reached near baseline values after 1 year. Scheimpflug densitometry showed weak correlation with CDVA over the 12-month follow-up period (r=−0.193).

Simulating Land Use: An Exploration of the Stability of a Two Zone City

This project simulates the Concentric Zone model (Ernest Burgess, 1925) using the agent-based simulation software COBWEB, which allows comparison of transportation costs in determining the distribution of agents after a set period of time. The energy an individual uses to move one grid cell is the parameter factor used to represent transportation costs. It was hypothesized that setting up this experiment to recreate a concentric zone environment will develop a stable environment with individual agents staying in their respective zones as determined by transportation costs. However, over a period of time, the agent population would diminish or the zones won’t be as clearly expressed.In the control experiment, each agent type stayed in their respective zones and the agent count remained consistent throughout the simulation. Two more experiments were performed to observe their respective effects on the model. By increasing the number of agents, this experiment had similar averages compared the control experiment, indicating that there is a carrying capacity in order to maximize the agent’s survival. By changing AI strategies, one of the agents completely died out, suggesting that the agent’s specific AI strategy for its movement and consumption is important to consider when performing experiments.Modelling the distribution of the agents and observing the key factors affecting this distribution is useful for urban planning and transportation management. Additional research to introduce parameters for housing costs is worth exploring in future research activities to provide more interesting and detailed results from the simulation.Ce projet simule le Plan Radiocentrique, un concept qui a été créé par Ernest Burgess, un économiste influencé par von Thünen (Ernest Burgess, 1925). En particulier, ce projet utilise « COBWEB, » un logiciel de simulation à base d'agents qui permet la comparaison entre les coûts de transport et d'autres facteurs essentiels pour déterminer le résultat. L'énergie qu'un individu utilise pour déplacer une cellule de la grille a été le paramètre facteur utilisé pour représenter les coûts de transport. L'établissement de cette expérience avec un but de recréer un environnement de zone concentrique permettra de créer un environnement stable avec des agents individuels qui restent dans leurs zones respectives telles que déterminées par les coûts de transport. Au fil du temps, la population des agents diminuera, en affectant la stabilité de la zone.La modélisation de la distribution des agents et l'observation des facteurs clés qui influencent cette distribution sont utiles pour la planification urbaine et la gestion des transports. Des recherches supplémentaires pour introduire des paramètres pour les frais de logement méritent d'être explorées.