scholarly journals Interplay of size and shape in miniaturized land snails

2018 ◽  
Author(s):  
Aydin Örstan
Keyword(s):  
Egg Size ◽  
Shell Height ◽  
Land Snails ◽  
Shell Shape ◽  
Functional Constraints ◽  
Surface Areas ◽  
Uniform Distributions ◽  
The Mean ◽  
Potential Factors ◽  
Body Whorl

ABSTRACTThe distribution of the mean greater shell dimensions of 2446 genera of stylommatophoran land snails consists of two groups peaking at 3 mm and 15.3 mm. The 3-mm group includes the miniature snails whose adult shell dimensions range from almost 0.8 mm to less than 1.5 mm. Relative surface area, shell thickness and egg size are discussed as potential factors that may limit the minimum shell dimensions. To obtain uniform distributions, the shell shape is expressed as the expanse angle, defined as the apex angle of a right triangle the height and the base of which are the shell height and diameter, respectively. In terms of expanse angles there are three shell shapes: tall (< 40°), flat (> 50°) and roughly equiaxial (40°-50°). The variation of shell shape with size was analyzed within the morphospace they form. At shell dimensions above 10 mm the lowest expanse angle is about 10°. Below 10 mm, the lower limit of the expanse angle increases as shells get smaller. As a result, no miniature species has a tall shell. It is proposed that two evolutionary functional constraints render small and narrow shells of miniaturized snails nonadaptive. These are the requirements to reduce surface areas to decrease water loss and to have enough volume and a wide enough body whorl to accommodate at least one egg.

60 Contact Hand Burns in Children: Still a Major Prevention Need

2020 ◽  
Vol 41 (Supplement_1) ◽  
pp. S39-S40
Author(s):  
Jaclyn M McBride ◽  
Kathleen S Romanowski ◽  
Soman Sen ◽  
Tina L Palmieri ◽  
David G Greenhalgh
Keyword(s):  
Graft Loss ◽  
Dorsal Surface ◽  
Skin Grafting ◽  
Secondary Surgery ◽  
Surface Areas ◽  
Palmar Surface ◽  
The Mean ◽  
Total Body ◽  
Hand Burns ◽  
Palmar Aspect

Abstract Introduction Since toddlers explore with their hands, contact burns continue to be a major pediatric problem. The purpose of this report is to review a pediatric burn unit’s 8-year experience with contact burns of the hand. Methods After IRB approval, a review of pediatric contact hand burns that occurred between 2006–2014 was performed. We examined the causes and outcomes in pediatric contact hand burns in a single pediatric burn program. Results In the 8-year span, 535 children suffered contact burns to the hand (67 per year). The majority suffered hands burns from an oven or stove (120). The other etiologies included burns from a fireplace (76), clothing iron (65), curling or straightening iron (50), and firepit or campfire (46). The mean age at time of injury was 2.62 years old, with a range of 2 months old to18 years old. Male children (339) typically burned their hands more than females (197). Locations of injury included the palmar surface, dorsal surface, fingers tips/thumb, wrist or a combination of several different areas. Most children burned the palmar aspect of their hand (384) compared to the dorsal aspect (61). These burns typically cover small total body surface areas (mean 1.08% TBSA), with only 2% of burns comprising &gt;5% TBSA. Approximately, 84% of these patients did not need surgery, but 86 (16%) had skin grafting (usually full-thickness) and 26% needed a secondary surgery. Of those that needed more than two, the average number of procedures was 3.6. Approximately 4.1% of patients needed a tertiary surgery. Causes for tertiary surgeries included contractures and graft loss. Out of twenty-two patients that needed a third surgery, 59% were due to graft loss and 41% were due to contractures. Conclusions Contact burns to the hand continue to be a major problem for toddlers. Children are most likely to burn themselves on an oven or stove, fireplace, clothing iron or curling/straightening iron. The palmar surface of the hand is the most likely site. While most children do not require surgery, approximately 16% require grafting. A significant number of those patients need reconstructive surgery. Clearly, current prevention efforts have failed to reduce these injuries. Applicability of Research to Practice Palm burns are common in young children. Efforts should focus on preventing these injuries.

scholarly journals Effects of low-pH stress on shell traits of the dove snail, <i>Anachis misera</i>, inhabiting shallow-vent environments off Kueishan Islet, Taiwan

2015 ◽  
Vol 12 (9) ◽  
pp. 2631-2639 ◽  
Author(s):  
Y. J. Chen ◽  
J. Y. Wu ◽  
C. T. A. Chen ◽  
L. L. Liu
Keyword(s):  
Shell Length ◽  
Shell Thickness ◽  
Expression Profiles ◽  
Shell Shape ◽  
Natural Environments ◽  
Additional Information ◽  
Shell Width ◽  
T1 And T2 ◽  
Body Whorl ◽  
Protein Expression Profiles

Abstract. The effects of naturally acidified seawater on shell traits were quantified through the comparison of dove snails (Family: Columbellidae) Anachis misera from vent environments with Euplica sp. from non-vent sites in northeastern Taiwan. Samples of A. misera were collected around a shallow vent (24.8341° N, 121.96191° E), which included the east, south, southwest, and northwest sites. An absence of Anachis snails was found in the most acidic north site (pH 7.19–7.25). Based on the similarities of protein expression profiles, the Anachis snails were classified into two groups, i.e., V-South (pH 7.78–7.82) and V-Rest (pH 7.31–7.83). Comparing their shell traits to the non-vent Euplica sp. from Da-xi (DX) and Geng-fang (GF) (pH 8.1–8.2), a difference in shell shape (shell width : shell length) was found, with the populations having more globular shells than the non-vent ones. The means of shell width were significantly different among sites (p < 0.01), with a descending order of GF > DX > V-South and V-Rest. The relationships of shell length to total weight were curvilinear for both Anachis and Euplica snails. The logarithmically transformed slopes differed significantly among sites, and the mean body weight of the GF population was greater than that of the others (p < 0.01). Positive correlations between shell length and shell thickness of body whorl (T1) and penultimate whorl (T2) were only observed in non-vent GF and DX populations. Anachis snails from vent sites were thinner in T1 and T2 compared to the Euplica snails from non-vent sites (p < 0.05). Within each vent group, shell thickness between T1 and T2 was insignificantly different. Between vent groups, T1 and T2 from V-Rest showed a decrease of 10.6 and 10.2%, respectively, compared to V-South ones. The decrease of T1 and T2 between vent Anachis snails and non-vent Euplica snails was as great as 55.6 and 29.0%, respectively. This was the first study to compare snail's morphological traits under varying shallow-vent stresses with populations previously classified by biochemical responses. Overall, the shallow-vent-based findings provide additional information from subtropics on the effects of acidified seawater on gastropod snails in natural environments.

A geometric analysis of growth in gastropod shells, with particular reference to turbinate forms

1983 ◽  
Vol 63 (4) ◽  
pp. 777-797 ◽  
Author(s):  
S. U. K. Ekaratne ◽  
D. J. Crisp
Keyword(s):  
Conversion Factor ◽  
Shell Height ◽  
Geometric Analysis ◽  
Logarithmic Spiral ◽  
Maximum Growth ◽  
Relative Magnitude ◽  
Shell Shape ◽  
Growth Band ◽  
Apical Angle ◽  
Image Position

Nucella lapillus and Littorina littorea afford examples of turbinately coiled shells with no space between the columella and the inner face of the whorls. Three constants are sufficient to determine the form of such shells: λ, the ratio between diameters of successive whorls; β, the semi-apical angle and ρ, the ratio of aperture length and breadth in the apertural plane passing through the axis. The variation of these three constants with size was examined and shown to be relatively small and insignificant in Nucella, but in Littorina it was significant.For Nucella and Littorina these shell characteristics were used to relate for the nth whorl, the length along the shell spiral (ln) to the shell height (Hn), the latter being the measure usually employed in growth studies. This relation was derived mathematically and confirmed empirically aswhere α is the angle of the logarithmic spiral given by α = tan−1 2π sin β/loge λ. The increased resolution of the micro-growth band increments, which are measured along the shell spiral was directly related to the ln:Hn ratios.Since the formula for the ln/Hn ratio (= shell conversion factor) includes λ, β and ρ, the three constants necessary to determine shell form in turbinately coiled shells of the type described, the shell conversion factor may be a better index of shell shape than indices based on a single constant. In species where the shell grows isometrically this ratio will remain constant, whereas changes in shell shape with size will influence this ratio. Such changes in shell shape during growth can be quantified in terms of the shell constants and when included in calculating the shell conversion factor, will show the relative magnitude of shell shape changes brought about by growth. The shell conversion factor may also be used to study the effects of ecological variations on the geometry of the shell.The conical shell of the limpet, Patella vulgata, is geometrically a much simpler system in which direct shell measurements were used to relate length along the direction of maximum growth to the antero-posterior diameter of aperture.

scholarly journals Comparison of power of modified Jarque-Bera normality tests and selected tests of normality

2008 ◽  
Vol 56 (6) ◽  
pp. 137-148 ◽  
Author(s):  
Luboš Střelec
Keyword(s):  
Stock Exchange ◽  
Financial Time Series ◽  
Simulation Studies ◽  
Test Paper ◽  
Monthly Average ◽  
Financial Time ◽  
Uniform Distributions ◽  
Source Data ◽  
The Mean ◽  
Heavy Tailed

The aim of this paper is to modify the classical Jarque-Bera test and the robust Jarque-Bera test of normality. We use the median as an estimator instead of the mean in the classical Jarque-Bera test and in the robust Jarque-Bera test. This leads to the modified Jarque-Bera test and the modified robust Jarque-Bera test. Paper also demonstrates results of simulation studies of power of such tests with the various alternatives – light tailed alternatives as exponential, lognormal and gamma distribution, heavy tailed alternatives as Cauchy, Laplace, t3, t5 and logistic distributions and short tailed alternatives as beta and uniform distributions. These tests of normality are also used for normality testing of selected datasets of financial time series. Source data include logarithmic returns of monthly ave­ra­ge prices of Prague stock exchange index PX and monthly average prices of CZK/EUR exchange rate in the period from 2000 to 2007.

scholarly journals Dynamics of stock for yesso scallop Mizuhopecten yessoensis (Jay, 1856) in the northwestern Tatar Strait from the beginning of its fishery to nowadays

2021 ◽  
Vol 201 (3) ◽  
pp. 533-546
Author(s):  
P. A. Dulenina ◽  
A. A. Dulenin
Keyword(s):  
Shell Height ◽  
Mizuhopecten Yessoensis ◽  
Tatar Strait ◽  
Yesso Scallop ◽  
The Mean ◽  
Commercial Value ◽  
Northwestern Tatar Strait ◽  
Commercial Stock

Settlements of yesso scallop Mizuhopecten yessoensis in the northwestern Tatar Strait (within the waters of Khabarovsk Region) are considered on the data of scuba (< 20 m depth) and dredge (> 20 m depth) surveys conducted in 2001–2018. To 2018, only two settlements remain in this area from 9–12 ones in 2010–2014; both remained settlements have no commercial value. Trend to decreasing of the settlements density is shown: the mean density was 3.0 ind./m2 in 2001, 0.20 ind./m2 in 2010, and 0.0005 ind./m2 in 2018. Commercially valuable scallops with the shell height > 120 mm prevailed in the settlements (86–100 %), whereas juveniles were rare or absent (1.6 %, on average) in all years of surveys. CPUE decreased from 200 kg/diver/hour in 2001–2003 to 10 kg/diver/hour in 2018. These changes are obviously reasoned by overexploitation of the population using dredging and scuba gathering. Total commercial stock of yesso scallop dropped to the minimal value in 2018: 200 t, that was in 4.5 times lower than the established limit. Thus, 5 years ban is established for M. yessoensis landing in the area.

Divergent Shell Shape as an Antipredator Adaptation in Tropical Land Snails

2008 ◽  
Vol 172 (5) ◽  
pp. 726-732 ◽  
Author(s):  
Masaki Hoso ◽  
Michio Hori
Keyword(s):  
Land Snails ◽  
Shell Shape

scholarly journals Land snails as experimental animals: a study of the variability and distribution of individual weights in Helix aspersa snails born from the same clutch

1990 ◽  
Vol 24 (1) ◽  
pp. 1-4 ◽  
Author(s):  
R. Sanz Sampelayo ◽  
J. Fonolla ◽  
F. Gil Extremera
Keyword(s):  
Normal Distribution ◽  
Growth Curve ◽  
Original Data ◽  
Helix Aspersa ◽  
Land Snails ◽  
Central Tendency ◽  
Experimental Conditions ◽  
Experimental Animals ◽  
Coefficients Of Variation ◽  
The Mean

A study was carried out to examine the distribution of individual weights in Helix aspersa snails, the aims being to establish the best estimate of the ponderal growth and also to obtain a model growth curve. Four groups of 20 snails from the same clutch were analysed and kept under experimental conditions from birth up to 6 months. The variability of their individual weights within groups was studied by calculating the coefficients of variation every 15 days. At the same time, the assumed normal distribution of those weights was being tested. The coefficients of variation increased with age and the assumed normal distribution of individual weights had to be rejected. By means of a log transformation of the original data, a model growth curve was constructed, and was used to assess the possibility of estimating age from weight. We finally reached the conclusion that median weight, rather than the mean, would be a better measure of central tendency to use until it is possible to obtain selected populations. The difficulty of estimating age from weight is emphasized.

A decadal study of biometric and imposex indices in two gastropods

2019 ◽  
Vol 99 (7) ◽  
pp. 1601-1614
Author(s):  
J. M. Ruiz ◽  
B. Carro ◽  
N. Albaina ◽  
L. Couceiro ◽  
M. Quintela ◽  
...  
Keyword(s):  
Vas Deferens ◽  
Shell Height ◽  
Chemical Analyses ◽  
Nucella Lapillus ◽  
Nw Spain ◽  
Potential Applications ◽  
Penis Length ◽  
The Mean ◽  
Tbt Biomonitoring ◽  
Tbt Pollution

AbstractWe have monitored tributyltin (TBT) pollution in Galicia (NW Spain) for more than a decade by means of assessing gastropod imposex in populations of Nucella lapillus (N ≥ 34) and Tritia reticulata (N ≥ 18) at regular intervals. Several thousand specimens were processed to obtain their shell height (SH), penis length (PL) and vas deferens sequence (VDS); imposex indices (including the VDS index, VDSI) were subsequently calculated. The regional mean SH of both females and males has not changed significantly in either species throughout the study. This also applies to the mean male PL in N. lapillus, but male T. reticulata penises surprisingly enlarged. On the contrary, the regional mean female PL (MFPL) and all imposex indices significantly decreased in both snails. Results confirm previous conclusions based on the chemical analyses of tissues and partial imposex observations. In addition, the close correlations between MFPL and VDSI show some potential applications to TBT biomonitoring.

scholarly journals CO2-induced low pH in an eastern oyster (Crassostrea virginica) hatchery positively affects reproductive development and larval survival but negatively affects larval shape and size, with no intergenerational linkages

2020 ◽  
Author(s):  
Jeff C Clements ◽  
Claire E Carver ◽  
Martin A Mallet ◽  
Luc A Comeau ◽  
André L Mallet
Keyword(s):  
Crassostrea Virginica ◽  
Shell Height ◽  
Reproductive Development ◽  
Eastern Oyster ◽  
Larval Survival ◽  
Low Ph ◽  
Shell Shape ◽  
Biological Sex ◽  
Positive Effects ◽  
Ph Conditions

Abstract In North America, studies regarding effects of CO2-induced low pH in bivalve aquaculture are largely restricted to the US Pacific coast. Studies on species from the northwest Atlantic are lacking. Furthermore, information on the roles of intergenerational exposure and biological sex in bivalve responses to low pH, particularly in an aquaculture-specific context, is scant. We tested if short-term (1 month) exposure to CO2-induced reductions in pHNBS affected the reproductive development of male and female eastern oysters (Crassostrea virginica) during hatchery-specific reproductive conditioning and whether maternal and/or paternal exposure influenced larval responses. Reduced pH (7.5–7.7) increased the rate of reproductive development in both males and females. There was no indication of intergenerational effects; adult pH conditions did not affect early larval development. In contrast, low pH conditions experienced by gametes during spawning, fertilization, and embryo incubation (48 h) resulted in higher larval survival (+6–8% from control), reduced shell height (−2 to 3 µm), and increased deformities (abnormal shell shape; +3–5%). We suggest that local adaptation to acidic land runoff may account for the positive effects of low pH observed in this study. Bioeconomic assessments are now needed to understand the implications of reduced pH on aquaculture operations in these regions of Atlantic Canada.

A comparison of capillary hydraulic conductivities in postural and locomotor muscle

1982 ◽  
Vol 243 (3) ◽  
pp. H491-H497
Author(s):  
P. F. McDonagh ◽  
R. W. Gore
Keyword(s):  
Hydraulic Conductivity ◽  
Latissimus Dorsi ◽  
White Muscle ◽  
Capillary Surface ◽  
Surface Areas ◽  
Red Muscle ◽  
Postural Muscle ◽  
Anterior Latissimus Dorsi ◽  
The Mean ◽  
Muscle Capillaries

In a comparative skeletal muscle study Folkow and Halicka (Microvasc. Res. 1: 1-14, 1968) reported that the capillary filtration coefficient (CFC) of postural (red) muscle was two times the CFC of locomotor (white) muscle. It was concluded that the twofold difference in CFC was due solely to a difference in the perfused capillary surface areas (Sf) of red vs. white muscle. However, CFC is the product of capillary hydraulic conductivity (LP) and Sf. Hence their conclusion assumed that the average LP of red muscle capillaries is exactly equal to the average LP of white muscle capillaries. The following study was undertaken to test the validity of this assumption. The microocclusion procedures and analytical model described by Lee et al. (Circ. Res. 28: 358-370, 1971) and Gore [Am. J. Physiol. 242 (Heart Circ. Physiol. 11): H268-H287, 1982] were used to determine LP. Independent measurements of LP were recorded from single capillaries in red, anterior latissimus dorsi (ALD) and white, posterior latissimus dorsi (PLD) muscles of chickens anesthetized with L.A. Thesia. We found that the mean capillary hydraulic conductivity in postural muscle [(LP)ALD = 0.20 +/- 0.06 (SE) micrometers . s-1 . cmH2O-1 (n = 11)] was significantly different from the mean capillary hydraulic conductivity in locomotor muscle [(LP)PLD = 0.061 +/- 0.01 micrometers . s-1 . cmH2O-1 (n = 14)] (P less than 0.05). These results provide direct evidence that observed differences in red vs. white muscle CFC's may not be due solely to different perfused capillary surface areas but may also be due to differences in capillary hydraulic conductivity.

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