Use of bone histology in estimating the age of frogs (Rana perezi) from a warm temperate climate area

1996 ◽  
Vol 74 (10) ◽  
pp. 1914-1921 ◽  
Author(s):  
Marisa Esteban ◽  
Mario García-París ◽  
Jacques Castanet
Keyword(s):  
Bone Growth ◽  
Extended Period ◽  
Temperate Climate ◽  
Water Frogs ◽  
Wide Range ◽  
Body Sizes ◽  
Males And Females ◽  
Warm Temperate ◽  
Sexually Mature ◽  
Rana Perezi

The structure and the histological expression of annual bone growth marks of Iberian water frogs (Rana perezi) from a warm temperate climate region (southwestern Spain) differ markedly from the pattern observed in colder climate populations. Forty-eight percent of winter growth marks appeared to be annuli; 52% are lines of arrested growth but 20% of these are weakly expressed. Annuli or lines of arrested growth were very diffuse or absent in 7% of the 103 individuals studied, suggesting that variations in climate have a stronger influence on growth-mark formation than was previously considered. Males and females are sexually mature in their second year, although some males mature at 1 year of age and some females at 3 years. The oldest males were 4 years old, 1 year younger than males from northern populations. The oldest female was 6 years old. The wide range of body sizes among the 1-year-old froglets can be explained by the extended period of metamorphosis, from July to November.

Assessing the Ergonomic Benefits of a New Adjustable Forklift Backrest

2020 ◽  
Vol 64 (1) ◽  
pp. 976-980
Author(s):  
Pranav Madhav Kuber ◽  
Ehsan Rashedi
Keyword(s):  
Comparative Study ◽  
Motion Capture ◽  
Center Of Pressure ◽  
Body Movement ◽  
Pressure Change ◽  
Motion Capture System ◽  
Design Features ◽  
Wide Range ◽  
Body Sizes ◽  
The Mean

A new forklift backrest has been developed by incorporating adjustability concepts into the design to facilitate comfort to a wide range of users. We have conducted a comparative study between the new and original backrests to assess the effectiveness of design features. Using the phenomenon of restlessness, discomfort of the user was associated with the amount of body movement, where we have used a motion- capture system and a force platform to quantify the individuals’ movement for a wide range of body sizes. Meanwhile, subjective comfort and design feedback were collected using a questionnaire. Our results showed a reduction in the mean torso movement and the maximum center of pressure change of location by 300 and 6 mm, respectively, for the new design. Taking advantage of adjustability feature, the new backrest design exhibited enhanced comfort for longer durations and reduced magnitude of discomfort for a wide range of participants’ body sizes.

scholarly journals Sources of variation in the feeding ecology of the piked spurdog (Squalus megalops): implications for inferring predator–prey interactions from overall dietary composition

2005 ◽  
Vol 62 (6) ◽  
pp. 1076-1094 ◽  
Author(s):  
J. Matías Braccini ◽  
Bronwyn M. Gillanders ◽  
Terence I. Walker
Keyword(s):  
Spatial And Temporal Variation ◽  
Dietary Composition ◽  
Bootstrap Analysis ◽  
Predator Prey ◽  
Ecological Relationships ◽  
Wide Range ◽  
Opportunistic Predator ◽  
Sources Of Variation ◽  
Males And Females ◽  
Prey Items

Abstract Sources of variation in dietary composition were examined in the piked spurdog (Squalus megalops). The species is an opportunistic predator that consumes a wide range of prey items. When importance of prey was measured by weight or occurrence, S. megalops preyed largely on molluscs and teleosts. However, when number of prey was considered, the main items were crustaceans. A bootstrap analysis showed that considerable variability can be expected in the importance of prey items in the species' overall diet. Regional, seasonal, and ontogenetic differences in dietary composition were found, but there were no differences between mature and immature sharks or between males and females. The spatial and temporal variation in diet exhibited by S. megalops and the intrinsic natural variability of the dietary composition of this opportunistic predator suggest that studies that infer predator–prey interactions from overall diet are likely to miss information on the ecological relationships among species and thus account for only part of these interactions.

Population parameters of ringed seals (Phoca hispida Schreber, 1775) in the Svalbard area

1987 ◽  
Vol 65 (4) ◽  
pp. 1021-1027 ◽  
Author(s):  
Christian Lydersen ◽  
Ian Gjertz
Keyword(s):  
Sex Ratio ◽  
Ringed Seal ◽  
Adult Males ◽  
Population Parameters ◽  
Phoca Hispida ◽  
Age Class ◽  
Ringed Seals ◽  
Males And Females ◽  
The Mean ◽  
Sexually Mature

Samples were taken from 284 ringed seals (Phoca hispida) in the Svalbard area during April–July 1981 and March–April 1982. The age of 283 seals was determined by reading annuli in the cementum of the canine teeth. The mean age of the males was 11.3 years, and of the females, 14.9 years. Females were found to be significantly older than males. The mean length of sexually mature ringed seals was 128.9 cm for both sexes. The mean weight of adult males and females was 53.5 and 61.4 kg, respectively. Females were found to be significantly heavier than males. The sex ratio was 47.8% males and 52.2% females. Studies of microscopic sections of testis and epididymis from ringed seal males showed that 63, 75, and 80% of 5-, 6-, and 7-year-old animals, respectively, were sexually mature. The weights of testis and epididymis, diameters of tubuli, and the size of testis all showed a marked increase in the 5-year age-class. Macroscopic sections of ovaries from ringed seal females showed that 20, 60, and 80% of 3-, 4-, and 5-year-old animals, respectively, were sexually mature. The size of the ovaries showed a marked increase in the 5-year age-class. The ovulation rate of ringed seals from Svalbard was calculated to be 0.91.

Evaluation of the allergenicity of various types of urban parks in a warm temperate climate zone

Aerobiologia ◽  
2018 ◽  
Vol 35 (1) ◽  
pp. 57-71 ◽  
Author(s):  
I. Kasprzyk ◽  
T. Wójcik ◽  
P. Cariñanos ◽  
K. Borycka ◽  
A. Ćwik
Keyword(s):  
Urban Parks ◽  
Temperate Climate ◽  
Climate Zone ◽  
Warm Temperate ◽  
Temperate Climate Zone

scholarly journals Vegetation and climate from Late Quaternary Thimi Formation (Phaidhoka Section), Bhaktapur, Nepal

2015 ◽  
Vol 50 (1) ◽  
pp. 1-12
Author(s):  
Deepak Banjade ◽  
Kabir Sharma ◽  
Khum N. Paudayal
Keyword(s):  
Late Quaternary ◽  
Middle Part ◽  
Temperate Climate ◽  
Silty Clay ◽  
Pollen Diagram ◽  
Formation Zone ◽  
Palynological Study ◽  
Deltaic Deposit ◽  
Warm Temperate ◽  
Vegetation And Climate

The Thimi Formation is fluvio-deltaic deposit that constitutes the uppermost part of the sedimentary sequence in the Kathmandu Basin, and is featured by carbonaceous and diatomaceous clay, silty clay, silt, fine to medium grained sand beds, and thin to medium lignite beds. The Phaidhoka Section is located on the way to Nala from Chyamasingh, and is one of the major exposures of the Thimi Formation. Forty four samples were collected from 25 m thick surface exposure for palynological study. The study revealed the dominance of gymnosperm over the angiosperm and herbaceous members. The pollen diagram suggested Pinus, Picea and Quercus as the most dominant trees whereas Poaceae is other dominant among the grasses. Three major pollen assemblage zones were marked in the Thimi Formation. Zone P-I indicated warm temperate climate, whereas zone P-II and P-III indicated cold temperate climate. Molluscan operculum in the upper part indicated shallow water condition. The Bovid molars, limb and pelvic bones from the middle part of the section confirm the early findings of molar bones in this area.

scholarly journals The correlation between dimensional characteristics, live weight and fluff and feather level of obroshynska gray and obroshynska white natural groups geese

2017 ◽  
Vol 19 (74) ◽  
Author(s):  
V. S. Zaplatynsky
Keyword(s):  
Body Weight ◽  
Linear Growth ◽  
Correlation Coefficients ◽  
Live Weight ◽  
Natural Group ◽  
Male And Female ◽  
Body Sizes ◽  
Males And Females ◽  
Natural Groups

This article presents data on dynamics of linear growth and weight rates of obroshynska gray and obroshynska gray natural groups geese, factional fluff content, correlation coefficients between body weight and body sizes and amount of feathers. It has been found that male and female individuals of obroshynska gray natural group geese dominated by live weight of obroshynska white natural group geese. Particularly, this advantage in 90 days aged males was 549.4 (P < 0.05), in 120 days aged males – 635.6 (P < 0.01) and in 180 days aged males – 422.6 (P < 0.05) g, in females – 177.0, 461.8 (P < 0.01) and 401.8 g respectively. It has been also revealed the obroshynska gray natural group geese domination by researched body sizes in all geese ages, but it was only reliable in some cases. Geese of both sexes in both natural groups were characterized by high fluff and feather level. We investigated age, sex and interbreed differentiation on fluff and feather levels in studied geese groups. It should be noted that fluff and feather level was better in white geese indicating a better fluff and feather quality. The correlation coefficients between body weight and overall fluff and feather levels in females of obroshynska gray natural group geese dependent on ages and fluff and feather levels were between -0.30 – +0.63, in males – between -0.51 – +0.68 and in obroshynska white natural groups geese coefficients were between -0.29 – +0.70 and -0.30 до +0.82 respectively. It has been found the correlations between geese body sizes and fluff and feather levels. In males and females geese from abroshynska gray natural group depenent on ages, body sizes and fluff and feather levels coefficients were -0.49 – +0.81 and -0.76 – +0.88, and for obroshynska white natural group geese – -0.49 – +0.90 and -0.65 – +0.65.

scholarly journals Relative skull size as one of the factors limiting skull shape variation in passerines

2021 ◽  
Author(s):  
Oksana Shatkovska ◽  
Maria Ghazali
Keyword(s):  
Body Mass ◽  
Shape Variation ◽  
Absolute Size ◽  
Terrestrial Locomotion ◽  
Skull Shape ◽  
Skull Size ◽  
Dietary Preferences ◽  
Wide Range ◽  
Body Sizes ◽  
Biomechanical Constraints

Despite a considerable interest of researchers to the issue of variation in skull shapes of birds and factors influencing it, some drivers associated with the design features of an entire bird body, which are important for both successful terrestrial locomotion and flight, are overlooked. One of such factors, in our opinion, is relative skull size (skull length in relation to body mass), which can affect the position of the body's center of gravity. We tested effects of relative skull size, allometry (i.e. absolute skull size), and diet on variation in skull shape. The study was conducted on 50 songbird species with a wide range of body mass (8.3g to 570g) and dietary preferences (granivores, insectivores/granivores, insectivores, omnivores). Skull shape was analyzed using 2D geometric morphometrics. We revealed that similar patterns of skull shape occur among passerines with different body sizes and diets. The relative skull size predicted skull shape to a similar extent and with a similar pattern as the absolute size. In our opinion, the effect of the relative skull size on skull shape variation is likely due to biomechanical constraints related to flight.

scholarly journals The body-size dependence of mutual interference

2014 ◽  
Vol 10 (6) ◽  
pp. 20140261 ◽  
Author(s):  
John P. DeLong
Keyword(s):  
Population Dynamics ◽  
Body Size ◽  
Size Dependence ◽  
Empirical Support ◽  
Mutual Interference ◽  
The Body ◽  
Wide Range ◽  
Stabilizing Effect ◽  
Body Sizes ◽  
Size Scales

The parameters that drive population dynamics typically show a relationship with body size. By contrast, there is no theoretical or empirical support for a body-size dependence of mutual interference, which links foraging rates to consumer density. Here, I develop a model to predict that interference may be positively or negatively related to body size depending on how resource body size scales with consumer body size. Over a wide range of body sizes, however, the model predicts that interference will be body-size independent. This prediction was supported by a new dataset on interference and consumer body size. The stabilizing effect of intermediate interference therefore appears to be roughly constant across size, while the effect of body size on population dynamics is mediated through other parameters.

Optical properties of traditional clay tiles for ventilated roofs and implication on roof thermal performance

2018 ◽  
Vol 42 (4) ◽  
pp. 484-505 ◽  
Author(s):  
Elisa Di Giuseppe ◽  
Simona Sabbatini ◽  
Nikita Cozzolino ◽  
Pierluigi Stipa ◽  
Marco D’Orazio
Keyword(s):  
Optical Properties ◽  
Thermal Performance ◽  
Temperate Climate ◽  
Second Phase ◽  
Analysis Tool ◽  
Urban Heat ◽  
Indoor Comfort ◽  
The Impact ◽  
Clay Tiles ◽  
Warm Temperate

A remarkable advantage of clay tiles roof coverings in hot climates is the realization of a ventilated air layer between them and the roofing underlay that allows a natural and forced convection through the tiles joints and the channel from eaves to ridge, thus cooling the roof materials. However recently, in many countries, regulatory developments on buildings energy efficiency or buildings sustainability certification protocols are increasingly encouraging the use of alternative strategies, with the aim of reducing the urban heat island (UHI) effect and the buildings’ cooling consumptions. Among them, the use of ‘cool’ materials for roof covering. These mandatory or voluntary measures de facto push the construction products market towards specific directions, risking penalizing traditional components such as clay tiles. This article reports the results of experimental and numerical activities carried out in order to extensively characterize the optical properties of clay tile materials and investigate their impact, also coupled with above sheathing ventilation, on the thermal performance of a ventilated roof under warm-temperate climate. In the first phase of the research, the main optical properties of over 30 different clay products have been experimentally characterized in order to get a clear and extensive picture of such properties for the materials spread in the market. In a second phase, starting from the thermal data collected on an experimental real-scale building, a dynamic energy analysis tool was calibrated and used to perform simulations by varying the optical properties of the roof covering thus assessing the impact on the roof temperatures, also in comparison to a clay tiles roof. The results underline that the use of the above sheathing ventilation obtained through clay tiles is an effective strategy to reduce roof temperatures, even if covering materials are not qualified as ‘cool’, thus impacting on both UHI and indoor comfort.

scholarly journals Expansion of Human Pluripotent Stem Cell-derived Early Cardiovascular Progenitor Cells by a Cocktail of Signaling Factors

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Sadaf Vahdat ◽  
Sara Pahlavan ◽  
Elena Mahmoudi ◽  
Maryam Barekat ◽  
Hassan Ansari ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Large Scale ◽  
Culture Medium ◽  
Gene Expression Pattern ◽  
Extended Period ◽  
Scale Production ◽  
Chemical Screening ◽  
Wide Range ◽  
Cell Sources

Abstract Cardiovascular progenitor cells (CPCs) derived from human pluripotent stem cells (hPSCs) are proposed to be invaluable cell sources for experimental and clinical studies. This wide range of applications necessitates large-scale production of CPCs in an in vitro culture system, which enables both expansion and maintenance of these cells. In this study, we aimed to develop a defined and efficient culture medium that uses signaling factors for large-scale expansion of early CPCs, called cardiogenic mesodermal cells (CMCs), which were derived from hPSCs. Chemical screening resulted in a medium that contained a reproducible combination of three factors (A83-01, bFGF, and CHIR99021) that generated 1014 CMCs after 10 passages without the propensity for tumorigenicity. Expanded CMCs retained their gene expression pattern, chromosomal stability, and differentiation tendency through several passages and showed both the safety and possible cardio-protective potentials when transplanted into the infarcted rat myocardium. These CMCs were efficiently cryopreserved for an extended period of time. This culture medium could be used for both adherent and suspension culture conditions, for which the latter is required for large-scale CMC production. Taken together, hPSC-derived CMCs exhibited self-renewal capacity in our simple, reproducible, and defined medium. These cells might ultimately be potential, promising cell sources for cardiovascular studies.

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