Miracle-dz/UniFAR-FTUs huggingface dataset:
A Quantitative Analysis of the Three‐Dimensional Spatial Colonization by a Plant as Illustrated by White Clover (Trifolium repens L.)

A new method is described for measuring spatial colonization by plants from three‐dimensional (3‐D) records of their aerial morphology. Nonparametric indices were devised to quantify the space colonized by the plant by measuring the spatial dispersion of sets of points representing relevant morphological features of its architecture, such as the nodes and petiole tips. These indices are defined as the square root of the second‐order moments of these sets, i.e., as dispersion radii. They can be split into the components that characterize the major directions of colonization and those that analyze the contributions of the various morphological features. Horizontal dispersion can be visualized as an indicator ellipse (to characterize the anisotropy), and vertical dispersion as equivalent heights. The kinetics of spatial colonization are then characterized as the changes in these dispersion radii during the development of the plant. This method is illustrated using isolated white clover plants. Two phases can be distinguished in the growth of this species: (i) a phase of rapid horizontal colonization involving the petioles and (ii) a phase in which the rate of horizontal colonization becomes slower and steady and involves both internodes and petioles. Petioles therefore make a major contribution to both vertical and horizontal colonization. We also show that these conclusions could not have been reached using only organ lengths and that the usual assumptions about the function of petioles in white clover should be reconsidered. We argue that this is a general method that can be applied to most species and growth forms of plants. It should be particularly useful for analyzing plastic morphogenetic responses to light conditions and their contribution to light foraging as a complement to estimating light interception.
Physiology of exolaccase production by Thelephora terrestris

Thelephora terrestris, an ectomycorrhizal hymenomycete, produces extracellular laccase when grown in minimal liquid medium. The enzyme was characterized as a protein of 66 kDa. The optimal pH varied depending on the substrate utilized, being 5.0 for syringaldazine, 4.8 for guaiacol and 3.4 for ABTS. The Km was 2.52±0.4 μM for syringaldazine, 16±1.9 μM for ABTS and 120.6±4.9 μM for guaiacol. The secretion of laccase was biomass-dependent and independent of the glucose concentration in the medium. The addition of inducers did not increase laccase production which was dependent upon the ammonium phosphate concentration.
Do inter-colony differences in Cape fur seal foraging behaviour reflect large-scale changes in the northern Benguela ecosystem?

The northern Benguela ecosystem adjoining Namibia has undergone considerable changes in recent decades, with reductions and northwards shifts of key prey species that have had severe implications for marine top predator populations. We investigated how such environmental variability may impact foraging behaviour of the Cape fur seal Arctocephalus pusillus pusillus, using satellite telemetry on animals in northern, central and southern Namibia. We expected that seal foraging behaviour would reflect a gradient of deteriorating feeding conditions from north to south. Results showed that foraging trips were shorter in the central region, where seals fed over the continental shelf, than in the north or south, where seals fed at the shelf edge. However, whereas seals in the north showed strong fidelity to the colony at which they were tagged and to persistent, clustered foraging areas, seals in the south showed weak fidelity both to the colony at which they were tagged and to foraging areas, which were scattered and variable. Seals in the south also tended to migrate northwards to other colonies while concurrently adapting their foraging behaviour to local conditions. Flexible use of foraging space and colonies of Cape fur seals during the three-year period (2002-2004) demonstrates that the species is adapted for variable environments over time and space.
Amino Acid Absorption by Arctic Plants: Implications for Plant Nutrition and Nitrogen Cycling

Recent studies of nitrogen (N) cycling in arctic tundra have indicated that inorganic N supplied to plants by mineralization is not sufficient to meet the annual requirement of N by many tundra species. Whereas N mineralization is slow in tundra soils and concentrations of inorganic N are low, these soils have large stocks of both structural and soluble organic N. In light of these observations, kinetics of absorption of three amino acids (glycine, aspartic acid, and glutamic acid) were measured in dominant vascular plant species of the four major ecosystem types in arctic Alaska and compared with concentrations of free amino acids in soils. Absorption rates were measured on roots using '4C-labeled substrates. Concentrations of free amino acids in soil were measured on water-extracted samples by high pressure liquid chromatography. All species had higher capacity (Vmax) for ammonium uptake (measured using methylamine as an ammonium analogue) than for any amino acid. However, at concentrations observed in the field, uptake rates estimated for amino acids were similar to (glycine) or less than (aspartic and glutamic acids) that for ammonium. On the basis of these comparisons, uptake rates of the three amino acids together may account for between 10 and 82% of the total N uptake in the field, depending on species and community. Deciduous shrubs had higher uptake rates than the more slowly growing evergreen shrubs, suggesting that new growth created a sink that strongly influenced capacity for amino acid uptake. In general, ectomycorrhizal species had higher amino acid uptake than did non-mycorrhizal species. In species that were sampled from more than one community, amino acid uptake rates were highest in the community where a given amino acid was most abundant in the soil. The results indicate that, in arctic tundra, plants short-circuit the mineralization step of decomposition by directly absorbing amino acids. This implies that in the organic soils of these tundra systems (1) inorganic nitrogen is an inadequate measure of plant-available soil nitrogen, (2) mineralization rates underestimate nitrogen supply rates to plants, (3) the large differences among species in capacities to absorb different forms of N provide ample basis for niche differentiation of what was previously considered a single resource, and (4) by short-circuiting N mineralization, plants accelerate N turnover and effectively exert greater control over N cycling than has been previously recognized.
SNR Model for Generalized Droop With Constant Output Power Amplifier Systems and Experimental Measurements

Submarine optical transmission systems are commonly operated with constant output power amplifiers. The Gaussian Noise (GN) model of propagation was generally developed in the context of constant gain amplification and accounts for amplified spontaneous emission (ASE) noise and nonlinear interference (NLI) noise. Recently, new models have been proposed and developed to predict signal-to-noise ratio (SNR) models for systems with constant output power amplification that account for the phenomenon known as signal droop, or more broadly, generalized droop (GD). Here we describe a GD model within the context of noises as generated in the GN model, and then further including other distributed noise generation such as might occur for crosstalk in multicore optical fibers. The model results in simple expressions for SNR, signal power, and noise powers as a function of the number of identical spans. We provide numerical modeling confirmation of the analytical model for different formats, and experimental transmission data that is fully consistent with the model.
Maternal Effects and Germination Timing Mediate the Expression of Winter and Spring Annual Life Histories in Arabidopsis thaliana

In natural populations of the annual plant Arabidopsis thaliana, season of germination determines life history. Spring annuals overwinter as seeds and germinate and flower in spring. Winter annuals germinate in fall, overwinter as rosettes, and flower in spring. In many plant species, germination is affected by the maternal phenotype during seed production. In those that produce seeds on branches from the main stem and branches from basal nodes, like A. thaliana, there may be positional effects on germination. This study examines the effects of maternal branch type on germination in artificial seasonal spring and fall environments. Seeds from apical and basal branches of 41 accessions of A. thaliana were weighed and divided between spring (low temperature for 21 d) and fall (ambient temperature) germination environments. Maternal branch type had significant effects on germination fraction and seed mass, but the direction of the effect differed among accessions. The genetic correlation between seed mass and germination fraction was positive for seeds in the spring germination environment and negative in the fall germination environment. There was a positive longitudinal cline for seed mass, a negative longitudinal cline for germination fraction, and a latitudinal cline for germination fraction that depended on the germination environment. These results show that there is geographic variation in germination traits and suggest that genetic variation in mass can lead to variation in season of germination for A. thaliana.
Histopathological and Serum Biochemical Changes Following Oral Administration of Aqueous Crude Extracts of Hyptis suaveolens, Urena lobata and Cleome viscosa in Rats

The toxic effects of three plants Cleome viscosa, Hyptis suaveolens and Urena lobata on serum biochemical parameters and histopathology were studied in albino rats using crude aqueous extracts of the leaves of the plants for 28 days. The analysis of serum biochemical parameters such as alanine aminotransferase (ALT), aspartate amino -transferase (AST), alkaline phosphate (ALP) bilirubin, total protein (TP), albumin (ALB) and triglycerides (TGC) of the rats treated with Urena lobata Cleome viscosa did not show any significant increase in the parameters except the blood urea nitrogen (BUN) of the rats. The BUN and GGT of the rats administered with Hyptis suaveolens were increased significantly (P Cleome viscosa showed kidneys with generalized nephrosis of the tubular epithelial cells, lungs with severe emphysema and adrenal gland with hemosiderosis, thus the effect of Cleome viscosa may mean it is nephrotoxic. The organs of the rats treated with Hyptis suaveolens showed liver with peri-hepatic accumulation of proteineous material, kidneys with diffused area of nephrosis of tubular epithelial cells. These observations along with the increases in BUN, and GGT produced by extracts of Hyptis suaveolens may suggest that the plant is hepatotoxic and nephrotoxic in rats. Key Words: Cleome viscosa, Hyptis suaveolens, Urena lobata, biochemical, histopathology, rats, toxicity. Trop. Vet. Vol.22: (1) 12-18 (2004)
CHEMICAL COMPOSITION AND STRUCTURE OF THE CELL WALLS OF THE CONCHOCELIS AND THALLUS PHASES OF PORPHYRA TENERA (RHODOPHYCEAE) 1, 2

Purified cell walls were prepared from both the conchocelis and thallus phases of Porphyra tenera (Kjellm.). The nitrogen content of cell walls from the conchocelis was significantly greater than that for the thallus cell walls, being 3.35 ± 0.26% and 2.39± 0.03%, respectively. Amino acid analysis revealed important differences. The conchocelis cell wall hydrolyzates were richer in aspartic acid, glutamic acid, methionine, and basic amino acids. The thallus cell wall hydrolyzates, however, contained much more glycine and alanine than did those of the conchocelis. Hydroxyproline was not detected in cell walls of either phase. The neutral sugar content of cell wall hydrolyzates from the thallus was more than double that from the conchocelis being 83.6% and 34.5%, respectively. The former contained predominantly mannose which accounted for 72.2% of the neutral sugars while the latter was principally galactose (49.9%) and glucose (36.4%). Methylation analysis confirmed the presence of cellulose microfibrils in the conchocelis in contrast to xylan microfibrils in the thallus. The results establish that the conchocelis and thallus phases of P. tenera differ markedly in the structure and composition of the cell walls.
The Greenhouse Effect: Acclimation of Tomato Plants Growing in High CO2, Photosynthesis and Ribulose-1, 5-Bisphosphate Carboxylase Protein

Dans cette etude, les effets a long terme d'un enrichissement en CO 2 atmospherique sur la photosynthese sont examines chez des plants de tomate. Des mesures de contenu en ribulose-1,5-bisphosphate carboxylase et de son activite, ainsi que de l'activite photosynthetique sont effectuees au cours du developpement des feuilles
An Efficient Non-Linear Application Algorithm Predictive Model for a Multi Aircraft Landing Dynamic System AIRLADYS R2019A+

The aim of this paper is to set up an efficient nonlinear application algorithm predictive model for a multi aircraft landing dynamic system called “Aircraft Landing Dynamic System, Release 2019A+ version “AIRLADYS R2019A+”. This programming software combines dynamic programming technic for mathematical computing and optimisation run under AMPL and KNITRO Solver. It uses also a descriptive programming technic for software design. The user interfaces designed in Glade are saved as XML, and by using the GtkBuilder GTK+ object these can be loaded by applications dynamically as needed. By using GtkBuilder, Glade XML files can be used in numerous programming languages including C, C++, C#, Java, Perl, Python, AMPL, etc. Glade is Free Software released under the GNU GPL License. By these tools, the solved problem is a mathematical modelization problem as a non-convex optimal control governed by ordinary non-linear differential equations. The dynamic programming technic is applied because it is a sufficiently high order and it does not require computation of the partial derivatives of the aircraft dynamic. This application will be coded with Linux system on 64 bit operating system, but it can also be run on the windows system. High running performances are obtained with results giving feasible trajectories with a robust optimizing of the objective function.
Population size, plant performance, and genetic variation in the rare plant Arnica montana L. in the Rhön, Germany

Summary Phenotypic and genetic variation of the rare plant species Arnica montana L. were investigated in populations which had been fragmented by afforestation since 1930 in the Rhon, a mountain region in Central Germany. The aim of the study was to analyse whether small populations show less genetic variation and a lower fitness than large populations. Morphological and reproductive traits from eleven Arnica -populations of different size were examined in the field. Principal component analysis (PCA) reduced the nine traits measured to two main components, one of which correlated with phenotypic traits of the maternal plants in the field while the other corresponded to traits associated with offspring production, weight and germinability. The latter component, which we considered to be fitness-related, was significantly positively correlated with population size. We screened four isozymes to study the genetic variation of the populations. The mean number of alleles per locus (A), the mean observed heterozygosity (H o ), and the mean expected heterozygosity (H e ) were used to measure genetic variation. Population size and genetic variation were not significantly correlated. In addition, there were no significant correlations between the two main components of the PCA and genetic variation when controlling for population size. The results of the study suggest that small populations of plants exhibit a reduced reproductive success which could not be attributed to genetic erosion. It might be attributed to the longevity of the clonal A. montana that the genetic structure of the populations examined has remained unaffected by the habitat fragmentation so far. In addition, gene flow has probably still been taking place between the fragmented populations. Possibly, the reduced reproductive success of plants in the small populations was caused by missing availability of cross-compatible pollen because of a reduced set of S-alleles due to genetic drift. Furthermore, environmental maternal effects may have played an important role in reproduction and germinability.
Collaborative Leadership and Sustained Learner Academic Performance in Secondary Schools: A Blaming Game?

Abstract This article reports on a study that investigated how collaborative leadership can influence sustained learner academic performance in secondary schools. The key problem resounds about secondary schools that are unable either to sustain or improve learner academic performance when intervention strategies rolled out from the district offices are concluded. The literature pursued in the study covered collaborative leadership from both schools and district education offices and their impact on learner academic performance. Participants were circuit managers, subject advisors, principals and teachers. They completed open- ended questionnaires that sought to explain the relationship between collaborative leadership and sustained learner academic performance. Major findings indicated that participants (at the various levels of leadership) attribute low learner academic performance to all other involved parties except themselves. Thus, collaborative leadership within the school and between schools and district education offices is not enabling sustained learner academic performance.
Purple Nutsedge (Cyperus rotundus) Management in an Organic Production System

Abstract Research was initiated in March 2005 to test various integrated purple nutsedge management strategies over two growing seasons in an organic production system in which bell pepper was grown as a fall crop. Main plots consisted of integrated purple nutsedge management strategies from mid-March through July 2005 and 2006. The main-plot factors were (1) green polyethylene film, (2) clear polyethylene film, (3) turnip followed by (fb) green polyethylene film, (4) turnip fb clear polyethylene film, (5) tillage every 3 wk, and (6) fallow. Subplots consisted of hand-weeding, mulching with wheat straw, and no weeding following bell pepper transplanting in early August. Purple nutsedge tuber density was determined in March, August, and November each year. Viable tubers were categorized into three sizes: small (0.1 to 0.25 g), medium (0.26 to 0.50 g), and large (> 0.50 g). The initial tuber density averaged 500 small, 300 medium, and 110 large tubers m−2 in mid-March 2005 (910 total tubers m−2). Total tuber density increased to > 5,400 tubers m−2 in fallow, nonweeded plots by November 2006. Yearly tuber density remained relatively constant over the 2 yr when the fallow period was fb hand-weeding in the bell pepper crop. Density of large and medium tubers in the season-long management systems remained stable, whereas small tubers were prone to depletion over time. Frequent tillage or use of a polyethylene film with or without turnip resulted in a lower density of large tubers in November 2006 relative to fallow treatments, regardless of management intensity in bell pepper. The density of large tubers after 2 yr was similar among treatments involving frequent tillage or use of a polyethylene film with or without turnip, regardless of subplot treatment; this was also observed for medium tubers, but not for small tubers. All hand-weeded plots had comparable densities of small tubers, ranging from 25 to 194 viable tubers m−2. Intensive management involving frequent tillage or use of a translucent polyethylene film with or without turnip fb hand-weeding was not effective in eradicating purple nutsedge over two growing seasons. Purple nutsedge management costs calculated for each main-plot treatment revealed that use of a translucent polyethylene film alone was at least 4.5-fold more costly than frequent tillage. This research demonstrates that season-long management is essential to prevent purple nutsedge proliferation over time. Nomenclature: Purple nutsedge, Cyperus rotundus L. CYPRO; bell pepper, Capsicum annum L. ‘Heritage’; turnip, Brassica rapa L. ‘Seventop’.
Hydrolytic Rancidity in Milk. II. Some Management and Environmental Factors Influencing Lipolysis

Summary The results presented Confirm that susceptibility of milk to spontaneous rancidity varies with individuality of the cow, stage of lactation and season. The observation that season and stage of lactation also influence susceptibility of milk to temperature-induced rancidity is inconsistent with results reported previously. Advanced lactation, not advanced gestation, appeared to be the factor which contributed to the increase in rancidity toward the end of lactation. No evidence was obtained to indicate a relation between the estrus cycle and susceptibility of milk to rancidity. Results obtained following injections of a mixture of pituitrin and stilbestrol were inconsistent.
Thermal time model of Solanum sarrachoides germination

Abstract A population-based modelling approach was used to predict the occurrence of germination in Solanum sarrachoides (SOLSA) for different treatments. Seeds collected in Toledo (Spain) were exposed to constant temperatures, to temperatures alternating between 10 and 30°C and to gibberellins (GAs; 0, 50, 100, 150 and 1000 ppm) during a 24-h imbibition period. The following parameters were measured: base temperature (Tb), mean thermal time (θ T (50)) and the standard deviation of thermal time (σ θT ). The SOLSA seeds only germinated at constant temperatures when the highest GA concentration was applied. The thermal model suggests that the induction and loss of physiological dormancy following seed dispersal is achieved when temperatures vary and when a mean thermal time of 66 growing degree-days (d°C) and a Tb value of 16°C are achieved when no GA treatment was added. The concentration of GA applied under conditions of alternating temperatures has an additive effect, reducing θ T (50) up to threefold, from basal level (66 d°C) to 19.40 d°C, when the 1000 ppm GA treatment was applied. In this last case, the germination was accelerated by reducing Tb to 14°C. A 5–10°C change in temperature and a range of average temperatures of 20–27.5°C promoted the germination of SOLSA seeds to the greatest extent in the absence of GA. However, these conditions are not frequently encountered in the irrigated areas of the studied region; this finding could explain the limited ability of SOLSA to expand its range within this area.