Miracle-dz/UniFAR-FTUs huggingface dataset:
The xylem wedge as a functional unit – speculations on the consequences of flow in leaky tubes

summary Xylem, as a mixture of elements of large and small diameter, presents a paradox when viewed as a conductor of sap flow, since the quantity carried is determined by only the largest diameter elements. The paradox may be s resolved, and an important function for the smallest elements revealed, by consideration of flow in leaky tubes. It is shown how the balance between axial flow and leakage becomes critical at a certain diameter, called the critical diameter (D0). Below D0, no axial flow can occur. When a stack of connected tracheary elements of different diameters is assembled into a xylem wedge, as in the major veins of dicotyledon leaves, this wedge will act as a functional unit. Elements with D > D0 have axial flow, but those where DD0 have only radial flow. The mixture of elements then acts to concentrate solutes of the sap in the smallest elements at the apex of the wedge, left behind as the water leaves. The balance between radial and axial flow is also self-adjusting to changes in the longitudinal gradient of pressure. Consideration is given to the functions of these graded stacks in the metaxylem of leaves, of stem vascular bundles, within secondary wood, and in roots. It is shown how some xylem fibres may be expected to mediate exchanges of water and solutes, and may act as regulators of these exchanges in space and time. Some experimental demonstrations are presented of the predictions of this hypothesis.
Localisation de la transition bois initial - bois final dans un cerne de chêne par analyse microdensitométrique

Les largeurs de cerne et la position de la transition entre le bois initial et le bois final ont ete mesurees par analyse d'image de coupes microscopiques sur 96 cernes de chene rouvre (Quercus petraea Liebl.). Une analyse microdensitometrique a ete realisee sur des eprouvettes jumelles. La position de la transition bois initial - bois final a ete estimee sur chaque cerne en recherchant le point d'intersection du profil avec un seuil de densite determine de trois facons diferentes : (1) un seuil fixe, (2) un seuil flottant fonction des densites minimale et maximale du cerne et (3) un seuil flottant fonction de la densite moyenne. Chaque methode a ete experimentee avec differents parametrages, les largeurs de bois initial et final ainsi que leurs proportions etant chaque fois comparees a la reference anatomique. Les methodes (2) et (3) donnent les estimations les plus precises. La methode (2) est preconisee en raison de sa plus grande robustesse en cas de parametrage approximatif.
Genetic Diversity and Environmental Future

Increasing evidence indicates that a major portion of the enormous amount of polymorphism present in natural populations is maintained by natural selection. This polymorphism is necessary for adaptation. In the absence of a suitable amount of genetic diversity, a species will tend to die out in a changing environment. The genetic diversity of most species has been considerably reduced in historical times. Breeding for uniformity, and reduction in the number and size of wild populations, are largely responsible for this loss. Replacement of a natural forest ecosystem by modern agriculture reduces the genetic diversity by three orders of magnitude at the very least. A comparison of the estimated prehistoric and present amount of genetic diversity leads to the alarming conclusion that we may already have lost as much as 90% of the total genetic diversity of the biosphere. Further loss is expected because of the rapid growth of human population.
DIET SELECTION IN GOATS: A TEST OF INTAKE-RATE MAXIMIZATION

The mechanisms of diet choice by herbivores are poorly understood. We tested whether the preference of goats among five grass species was accounted for by differences in intake rate or differences in species-specific attributes of the grasses. When offered a choice between grass species, the goats selected diets that tended to maximize intake rate. Only a small amount of the residual variation was explained by the individual preference of goats for each grass species. The animals exhibited partial preferences, only leaving the lower intake-rate alternative ungrazed in a quarter of the trials. It is argued that the most likely explanation of this is the difficulty of discriminating between alternatives of similar intake rate. Discrimination error is likely to be a general explanation of mixed diets in herbivores, regardless of whether other explanations, such as rate maximization subject to nutrient constraints, also apply.
GAMT2 Encodes a Methyltransferase of Gibberellic Acid That is Involved in Seed Maturation and Germination in Arabidopsis

Salicylic acid methyltransferase (SAMT), benzoic acid methyltransferase (BAMT) and theobromine methyltransferase (TH) (henceforth, SABATH) family proteins belong to a unique class of methyltransferase that can methylate small molecular compounds including indole-3-acidic acid (IAA), salicylic acid (SA) and jasmonic acid (JA), in plants. Here we report that the GAMT2 protein, which has 34.2% similarity with IAMT1 in the amino acid sequence, can methylate gibberellic acid (GA). Bioinformatics analysis suggests that GAMT2 may be able to methylate one molecule larger than SA. GAMT2 is predominantly expressed in the developing seed embryo and endosperm in Arabidopsis. During seed germination, the expression of GAMT2 decreases until the cotyledons expand out of the seed coat. Overexpression of GAMT2 in Arabidopsis resulted in multiple phenotypes, including dwarfism, retarded growth, late flowering, and reduced fertility, which are similar to the phenotypes of GA-deficient mutants. Seed germination assay showed that GAMT2 overexpression in plants was hypersensitive to GA biosynthesis inhibitor (ancymidol) and abscisic acid (ABA) treatments, whereas the GAMT2 null mutant (SALK_075450) was slightly insensitive to such treatments, suggesting that GAMT2 may methylate GA or ABA. Enzyme activity analysis indicated that GAMT2 was able to methylate GA3 into Methyl-GA3in vitro, but could not methylate ABA. Microarray analysis on GAMT2 overexpression plants suggested that Methyl-GA may be an inactive form of GA in Arabidopsis. These data suggest that GAMT2 is involved in seed maturation and germination by modulating GA activity.
CANOPY TREE TURNOVER IN OLD‐GROWTH MESIC FORESTS OF EASTERN NORTH AMERICA

I studied the dynamic nature of old-growth, eastern U.S. forests by addressing the following questions: (1) How much do stand density, basal area, and size structure vary over time within several old-growth remnants? (2) How do mortality and growth rates vary with stem size? (3) How much does the importance of individual species vary over time and space? (4) At what rate do snags and stumps form and deteriorate? In 1990–1991, I resampled canopy stems within several old-growth remnants in the southern Appalachians, in Hueston Woods State Park, Ohio, and in the Tionesta Scenic and Research Natural Areas, Pennsylvania. I had previously sampled those sites in 1976–1977 using the point-centered quarter method. I remeasured the same trees and measured new trees if the old ones had died or if a new stem closer to the point than the old stem for that quarter had grown to ≥25 cm in diameter at breast height. Density and basal area changes were small. Density changes equaled −0.33%, −0.52%, and 0.00%/yr for the sou.
Performance of Laying Hens Fed Various Phosphorus Levels Continuously or Phase Fed Decremental Phosphorus Levels

Abstract Two experiments were conducted to determine the influence of dietary phosphorus levels on performance of White Leghorn hens. In Experiment 1, dietary available phosphorus (AP) levels of . 26, . 36, . 46, or . 56% were fed continuously from 24 to 68 weeks of age. Concurrently, diets containing . 46, . 36, and . 26% AP or . 56, . 46, and . 36% AP were “phase fed” during the age intervals of 24 to 36, 36 to 48, and 48 to 68 weeks, respectively. Dietary AP levels of . 16, . 26, . 36, and . 46% were fed from 27 to 71 weeks in Experiment 2. Also, phosphorus was phase fed in this experiment at levels of . 46, . 36, and . 26% AP or . 36, . 26, and . 16% AP for ages 27 to 39, 39 to 51, and 51 to 71 weeks, respectively. No significant effects of dietary AP levels were observed in either experiment with respect to rate of egg production, feed efficiency, egg weight, eggshell thickness, changes in body weight, or mortality. In Experiment 1, rate of egg production, egg weight, and eggshell thickness of the hens fed . 26% AP continuously were numerically less, and mortality was numerically greater, than those of hens fed higher AP levels. The percentage of ash and the quantities of phosphorus contained in carcasses (feather-free) at the end of Experiment 1 tended to be directly related to dietary AP level. Total carcass phosphorus of hens fed . 26% AP continuously was reduced significantly as compared with all other treatment groups except for the hens fed . 36% AP continuously. Neither concentration of carcass ash nor quantity of phosphorus in carcasses was affected consistently by dietary AP in Experiment 2. Assuming an average daily feed consumption of 95 to 100 g/hen, the results indicated that phase-feeding of dietary AP levels of . 46, . 36, and . 26% and possibly . 36, . 26, and . 16% during the age intervals of approximately 24 to 39, 39 to 51, and 51 to 71 weeks, respectively, will support high rates of egg production without excessive depletion of body phosphorus.
The Southwestern Indian Ocean as a potential marine evolutionary hotspot: perspectives from comparative phylogeography of reef brittle‐stars

The global biodiversity crisis requires the identification of regions with high evolutionary potential, i.e. evolutionary hotspots (evospots). We created an analytical framework based on comparative phylogeography and coalescent methods to assess the dynamics of diversification and population persistence in the reef ecosystem of a little‐studied region: the Southwestern Indian Ocean (SWIO).
Delayed sexual maturity and demographics of blanding's turtles (Emydoidea blandingii): implications for conservation and management of long-lived organisms

Abstract: A study of Blanding's turtles conducted during 27 of the last 37 years provided demographic data sufficient to examine how life-history characteristics may constrain population responses of long-lived organisms. Eight independent estimates of annual adult survivorship exceeded 93%. Nest survival was variable and ranged from 0.0 to 63% annually, with a mean of 44% from 1976 to 1984 and 3.3% from 1985 to 1991. Recruitment of juveniles and adults was sufficient to replace individuals estimated to have died during the study. A life table for the population resulted in a cohort generation time of 37 years and required a 72% annual survivorship of juveniles between 1 and 13 years of age to maintain a stable population. Population stability was most sensitive to changes in adult or juvenile survival and less sensitive to changes in age at sexual maturity, nest survival, or fecundity. The results from the present study indicate that life-history traits of long-lived organisms consist of co-evolved traits that result in severe constraints on the ability of populations to respond to chronic disturbances. Successful management and conservation programs for long-lived organisms will be those that recognize that protection of all life stages is necessary. Programs such as headstarting or protection only of nesting sites, in the absence of programs to reduce mortality of older juveniles and adults, appear to be less than adequate to save long-lived organisms such as sea turtles and some tortoises. The concept of sustainable harvest of already-reduced populations of long-lived organisms appears to be an oxymoron.
The Hypobranchial Gland in Morula Granulata (Gastropoda: Prosobranchia)

The hypobranchial gland ofMorula gramilata (Duclos) has been morphologically and histochemically characterized. The marginal zones of the gland have mucocytes and eosinophil cells while the median region has in addition ciliated cells and gland cells. Neurosensory cells are also present. Two types of mucous cells have been identified. Type I secrete a diastase-resistant, neutral mucopolysaccharide, while type II secrete PAS unreactive, strongly acidic and highly sulphated mucins. Exposure to low temperatures, ultraviolet rays and irritants resulted in the production of a purple dye.
The Equisetalean Genus Cruciaetheca nov. from the Lower Permian of Patagonia, Argentina

The new genus Cruciaetheca (Equisetales, Sphenopsida) is described from the Río Genoa Formation, Lower Permian of Chubut Province, Argentina. Ramified, whorled vegetative axes terminally bearing leaf whorls of the Phyllotheca type characterize this genus; some last‐order axes bear fertile internodes with whorls of cruciate sporangiophores between unmodified leaf whorls. We describe three species, Cruciaetheca patagonica (Feruglio) Cúneo et Escapa nov. comb. , Cruciaetheca feruglioi Cúneo et Escapa nov. sp. , and Cruciaetheca genoensis Cúneo et Escapa nov. sp. , that are diagnosed from vegetative and reproductive features. The new material is compared with other Paleozoic equisetaleans from different geographical regions. We reevaluate the use of the genus Phyllotheca in light of finding Phyllotheca foliar whorls associated with completely distinct reproductive characters. The systematic position of Cruciaetheca is discussed as well as the significance of its cruciate sporangiophores and other characters.
Oral Distribution of Genera, Species and Biotypes of Yeasts in Patients with Marginal Periodontitis

Yeasts can be members of the commensal flora in the healthy human mouth. They have also been found in periodontal pockets of patients with marginal periodontitis, but little is known about their distribution in other oral sites of such patients. The aim of the present study was to examine the distribution of genera, species and biotypes of yeasts in various sites of oral cavities of patients with chronic marginal periodontitis. Samples were taken from the periodontal pockets, buccal mucosa and palate of 70 marginal periodontitis patients and 45 healthy individuals. After cultivation yeast colonies were selected according to morphology and the biotype was determined by a commercial kit (ID 32C, bioMérieux, France). Oral yeasts were detected in 34.3% of the marginal periodontitis patients and 42.2% of the healthy subjects. Among the sites examined, the buccal mucosa was the major site for yeasts, being colonized in 31.4% of the marginal periodontitis patients and in 35.6% of the healthy subjects. Two genera (Candida and Saccharomyces), four species (C. albicans, C. dubliniensis, C. parapsilosis and S. cerevisiae) and 19 biotypes were identified from the marginal periodontitis patients, while one genus (Candida), two species (C. albicans and C. dubliniensis) and 11 biotypes were obtained from the healthy subjects. C. albicans was the most dominant species in all the oral sites. Among the other Candida species, C. dubliniensis dominated, being most prominent in the periodontal pockets. Two biotypes (7146340015 and 7347340015) of C. albicans and one biotype (7142100015) of C. dubliniensis were predominant in the marginal periodontitis patients, whereas three biotypes (7146340015, 7147340015 and 7347340015) of C. albicans dominated in the healthy subjects. The differences in the distribution of yeast species and biotypes may suggest cell, tissue or site tropism in oral yeast colonization.
On the Relationship of Social Evolution and Ecology in Ungulates

Much of the social behavior and organization of ungulates can be related to ecological parameters such as fiber content of forage, plant productivity, plant biomass, plant species diversity, productivity gradients, temporal and spatial fluctuations in productivity, habitat stability, food dispersion, three-dimensional structure of habitat, colonization, and predator density and diversity. These ecological variables can be linked via individual natural selection with the species' anti-predator strategies, emphasis on different channels of communication, relative frequency of damaging and non-damaging overt aggression, gregariousness and group structure, juvenile dispersal, home-range traditions, monogamy and polygamy, sexual dimorphism, territoriality, hierarchical rank structure, and plasticity of social structures. The ecological variables have primary manifestations which are behavior or which affect behavior, as well as secondary manifestations affecting behavior. There are logical links between the hypothesis linking ecology and behavior discussed here with some principles from bioenergetics, zoogeography, and paleontology. Although links do exist between ecology and behavior, they nevertheless represent distinct realms of natural selection in which social behavior appears as the more conservative element. The theoretical basis for this is discussed.
Comparative Study on the Aerial and Subterranean Flower Development in Amphicarpaea edgeworthii Benth. (Leguminosae: Papilionoideae), an Amphicarpic Species

Amphicarpy is a rare phenomenon in angiosperms. There are few studies on the floral development of aerial and especially subterranean flowers of the amphicarpic species. In this study, we examine the floral ontogeny of Amphicarpaea edgeworthii, an amphicarpic legume, using SEM. Three types of flowers can be produced in the same individual of the species: the subterranean flowers, solitary without subtending leaves; the aerial cleistogamous flowers, generally solitary in leaf axils; and the aerial chasmogamous flowers, one or two subtended by a bract. There is little difference in terms of the organ initiation among the three flower morphs. The order of initiation among whorls is sepals, petals, carpel, outer‐whorl stamens, and inner‐whorl stamens. Within each whorl, no obvious unidirectional order is found among the floral organ components. The development of petals, two‐whorl stamens, and a carpel in the aerial and subterranean flowers diverges at the mid‐ to late‐development stage. The mature aerial chasmogamous flowers become papilionaceous in the late stage by divergent form changes among petals, showing the potential for outcrossing. There is little difference in the floral development and morphology between the aerial and subterranean cleistogamous flowers. In contrast to aerial chasmogamous flowers, the specialized characteristics of cleistogamous flowers include partial suppression of petals and stamens. The findings in this study show that the subterranean flower was not a morphologically specific flower type diverged from the aerial cleistogamous flower.
Unspecialized exploitation of small carcasses by birds

During the winters of 1981–82 and 1982–83 we studied scavenging birds feeding on 14 Greylag Goose carcasses and intra- and inter-specific interactions occurring among them. The bird species most often visiting this carrion were: Red Kite, Magpie, Raven, White Stork, Marsh Harrier, Spanish Imperial Eagle, Griffon Vulture, Black Vulture, Grey Heron, Buzzard and Lesser Black-backed Gull. Each species' frequency at visiting carrion was not directly related to the abundance of the species in the area, but seemed to be related to inter and intraspecific competition, distance to roosts, and the economic return obtained from eating carrion. These species were not social at carrion, aggresion often taking place among them. Large sized species dominated smaller ones. We discuss similarities and differences of carrion exploitation in this bird guild and Old and New World Vulture guilds.
Role for Phospholipid Interactions in the Trafficking Defect of ΔF508-CFTR†

Cystic fibrosis commonly occurs as a consequence of the ΔF508 mutation in the first nucleotide binding fold domain (NBF-1) of CFTR. The mutation causes retention of the mutant CFTR molecule in the endoplasmic reticulum, and this aberrant trafficking event is believed to be due to defective interactions between the mutant NBF-1 domain and other cellular factors in the endoplasmic reticulum. Since the NBF-1 domain has been shown to interact with membranes, we wanted to investigate whether NBF-1 and CFTR interactions with specific phospholipid chaperones might play a role in trafficking. We have found that the recombinant wild-type NBF-1 interacts selectively with phosphatidylserine (PS) rather than phosphatidylcholine (PC). By contrast, NBF-1 carrying the ΔF508 mutation loses the ability to discriminate between these two phospholipids. In cells expressing ΔF508-CFTR, replacement of PC by noncharged analogues results in an absolute increase in CFTR expression. In addition, we detected progressive expression .
A fetus with 19q13.11 microdeletion presenting with intrauterine growth restriction and multiple cystic kidney

Abstract Background: Constitutional deletions of chromosome 19q were rarely reported in the literature. The array-comparative genome hybridization (CGH) helps to identify four children with 19q13 microdeletion and the microdeletion of 19q13.11 is a recent emerging syndrome. We report one fetus with 19q12q13.12 deletion diagnosed prenatally and compare with five cases in the literature. Case: The 29 year-old woman was at the 27th week of gestation. Prenatal ultrasound revealed severe intrauterine growth restriction and left side multiple cystic kidney with normal amniotic fluid index. Cordocentesis was performed for karyotyping and array CGH. Results: The karyotype of the fetus was considered as normal male. The BAC array CGH identified one deletion at chromosome 19q12q13.12. The oligonucleotide array CGH further characterized the size of the breakpoint (chr19:35,116, 199-42,994,905). After counselling, the pregnancy was terminated at the 28th week of gestation. The aborted fetus had hypospadias and facial dysmorphisms. Conclusions: Although a complete genotype-phenotype may not be established in these patients with 19q13 deletions, they shared some unique phenotypes and facial dysmorphisms. The clinician should keep in mind when anomalies are detected prenatally, array CGH may help to identify the etiology, which is critical for counselling.
Light-triggered action potentials in plants

Special attention is paid in this paper to the criteria of the light-triggered action potential, namely the all-or-none law, propagation, the occurrence of refractory periods. Such action potentials have been recorded in Acetabularia mediterranea, Asplenium trichomanes, Bryum pseudotriquetrum, Eremosphaera viridis and Concephalum conicum. In Acetabularia, action potentials are generated after sudden cessation of light stimuli of sufficient intensity. The depolarization phase of the action potential develops as a result of a transient reversal of the action of the electrogenic Cl- pump. This is a principle of the "metabolic" action potential hypothesis proposed by Gradmann. In the gametophytes of Aspleniam trichoma­nes and Bryum pseudo triquetrum, action potentials are triggered on illumination. Gutation starts 1.5-2 seconds after the passage of an action potential. The active water secretion facilitates fertilization. In the unicellular fresh water alga, Eremosphaera viridis, action potential-like responses are evoked after light termination. The process responsible for its appearance is the opening of potassium channels in the plasmalemma. The liverwort, Conocephalum conicum, generates action potentials in response to light, electrical, chemical and mechanical stimuli. Calcium and potassium channels as well as proton pumps are involved in electrogenesis of action impulses in the species. Excitation causes a significant increase in the respiration rate. The role of action impluses as mediators in a system of a metabolism control is discussed.