Size frequency, dispersal distances and variable growth rates of young sharks in a multi‐species aggregation

Numerous dinosaur bone beds have been found in the Upper Cretaceous Two Medicine Formation. Taphonomy and size-frequency profiles for the most common skeletal elements of six predominantly hadrosaurid and (or) lambeosaurid assemblages were compared. All six localities are single, highly concentrated bone horizons within silty mudstones. Most are monospecific with some degree of skeletal association, parautochthonous, and likely the result of mass mortality. Four are associated with small lacustrine or waterhole environments and may be the result of drought-related mortality. Within the Two Medicine Formation drought was apparently a common mechanism for generating fossil assemblages.Both hadrosaurids and lambeosaurids appear to have been gregarious. Lack of association between small (total length < 3 m) and larger individuals suggests either that juvenile growth rates were as rapid as large ungulates or less likely, that juveniles had a period of noninteraction with adults, perhaps dwelling in strictly juvenile groups. In Maiasaura peeblesorum, reproduction appears to have been synchronous among herd members and seasonal. Additionally, mortality was high for juveniles and dropped off rapidly as animals approached adult size.

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Testing size–frequency distributions as a method of ontogenetic aging: a life-history assessment of hadrosaurid dinosaurs from the Dinosaur Park Formation of Alberta, Canada, with implications for hadrosaurid paleoecology

Paleobiology ◽

10.1017/pab.2020.2 ◽

2020 ◽

Vol 46 (3) ◽

pp. 379-404

Author(s):

Mateusz Wosik ◽

Kentaro Chiba ◽

François Therrien ◽

David C. Evans

Keyword(s):

Life History ◽

Body Size ◽

Frequency Distribution ◽

Growth Rates ◽

Long Bone ◽

Size Frequency Distribution ◽

Frequency Distributions ◽

Size Frequency ◽

Combining Data ◽

Dinosaur Park Formation

AbstractHadrosaurid dinosaurs, the dominant large-bodied terrestrial herbivores in most Laurasian Late Cretaceous ecosystems, have an exceptional fossil record consisting of many species known from partial ontogenetic series, making them an ideal clade with which to conduct life-history studies. Previous research considered the Dinosaur Park Formation (DPF) of Alberta as an attritional, or time-averaged, sample and interpreted size–frequency distribution of long bones collected from the DPF with three size classes to suggest that hadrosaurids from the DPF attained near-asymptotic body size in under 3 years. This conflicted with previously published osteohistological estimates of 6+ years for penecontemporaneous hadrosaurids from the Two Medicine Formation (TMF) of Montana, suggesting either extreme variation in hadrosaurid growth rates or that size–frequency distributions and/or osteohistology and growth modeling inaccurately estimate ontogenetic age.We tested the validity of the previously proposed size–age relationship of hadrosaurids from the DPF by significantly increasing sample size and combining data from size–frequency distributions and osteohistology across multiple long-bone elements. The newly constructed size–frequency distributions typically reveal four relatively distinct size–frequency peaks that, when integrated with the osteohistological data, aligned with growth marks. The yearling size class was heavily underrepresented in the size–frequency distribution. If not due to preservation, this suggests that either juvenile (<2 years of age) hadrosaurids from the DPF had increased survivorship following an initially high nestling mortality rate or that yearlings were segregated from adults. A growth-curve analysis revealed asymptotic body size was attained in approximately 7 years, which is consistent with hadrosaurids from the TMF. The data suggest size–frequency distributions of attritional samples underestimate age and overestimate growth rates, but when paired with osteohistology can provide unique life-history insights.

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Population studies of juvenile Trochus niloticus on a reef flat on the north-eastern Queensland coast, Australia

Marine and Freshwater Research ◽

10.1071/mf96002 ◽

1997 ◽

Vol 48 (3) ◽

pp. 211 ◽

Cited By ~ 15

Author(s):

Laura L. Castell

Keyword(s):

Frequency Distribution ◽

Growth Rates ◽

Reef Flat ◽

Population Studies ◽

Size Frequency Distribution ◽

Shell Width ◽

The North ◽

Size Frequency ◽

North Eastern ◽

Trochus Niloticus

Transects and quadrats were used to sample the distribution and density of Trochus niloticus, recruitment, growth rates of juveniles, and characteristics of the microhabitat, on an intertidal reef flat at Orpheus Island between 1993 and 1995. Individuals between 1·5 and 62 mm shell width (SW) were found in all parts of the reef flat. Their density averaged 0·178 and 0·115 individuals m-2 in 1993 and 1994, respectively. Juveniles were found in groups of 2–4 individuals m-2 more frequently than would occur by chance, but denser aggregations were rare. As juveniles increased in size, there was a change in microhabitat: from small rubble (<10 mm) to larger rocks and coral bench and from shallow pools (<10 mm deep) to deeper pools. The size–frequency distribution was bimodal during parts of the year, suggesting seasonality in recruitment. Growth rates ranged between 2·3 and 2·6 mm SW month-1. In relation to the seeding of cultured juveniles for population enhancement, the results indicate that seeding densities should be <5 individuals m-2. Shallow areas with abundant small rubble may represent favourable conditions for individuals of <15 mm SW, but deeper areas with larger rocks are better for individuals of 15 mm SW.

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Response of benthic foraminifera to ocean acidification in their natural sediment environment: a long-term culturing experiment

Biogeosciences Discussions ◽

10.5194/bgd-10-9523-2013 ◽

2013 ◽

Vol 10 (6) ◽

pp. 9523-9572 ◽

Cited By ~ 1

Author(s):

K. Haynert ◽

J. Schönfeld ◽

R. Schiebel ◽

B. Wilson ◽

J. Thomsen

Keyword(s):

Ocean Acidification ◽

Frequency Distribution ◽

Growth Rates ◽

Organic Content ◽

Specific Response ◽

Natural Sediment ◽

Size Frequency Distribution ◽

Saturation State ◽

Carbonate Production ◽

Size Frequency

Abstract. Calcifying foraminifera are expected to be endangered by ocean acidification, However, the response of a complete community kept in natural sediment and over multiple generations under controlled laboratory conditions has not been constrained to date. During six month incubation, foraminiferal assemblages were treated with pCO2 enriched seawater of 430, 907, 1865 and 3247 μatm pCO2. The fauna was dominated by Ammonia aomoriensis and Elphidium species, whereas agglutinated species were rare. After 6 months incubation, pore water alkalinity was much higher in comparison to the overlying seawater. Consequently, the saturation state of Ωcalc was much higher in the sediment than in the water column in all pCO2 treatments and remained close to saturation. As a result, the life cycle of living assemblages was largely unaffected by the tested pCO2 treatments. Growth rates, reproduction and mortality, and therefore population densities and size-frequency distribution of Ammonia aomoriensis varied markedly during the experimental period. Growth rates varied between 25 and 50 μm per month, which corresponds to an addition of 1 or 2 new chambers per month. According to the size-frequency distribution, foraminifera start reproduction at a diameter of 250 μm. Mortality of large foraminifera was recognized, commencing at a test size of 285 μm at a pCO2 ranging from 430 to 1865 μatm, and of 258 μm at 3247 μatm. The total organic content of living Ammonia aomoriensis has been determined to be 4.3% of dry weight. Living individuals had a calcium carbonate production rate of 0.47 g m−2 yr−1, whereas dead empty tests accumulated at a rate of 0.27 g m−2 a−1. Although Ωcalc was close to 1, some empty tests of Ammonia aomoriensis showed dissolution features at the end of incubation. In contrast, tests of the subdominant species, Elphidium incertum, stayed intact. This species specific response could be explained by differences in the elemental test composition, in particular the higher Mg-concentrations in Ammonia aomoriensis tests. Our results emphasize that the sensitivity to ocean acidification of endobenthic foraminifera in their natural sediment habitat is much lower compared to the experimental response of specimens isolated from the sediment.

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Reduced growth rates of hair in mice following radiation

Archives of Dermatology ◽

10.1001/archderm.94.4.491 ◽

1966 ◽

Vol 94 (4) ◽

pp. 491-498 ◽

Cited By ~ 3

Author(s):

F. D. Malkinson

Keyword(s):

Growth Rates

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Institutional Theory of Endless Redistribution

Voprosy Ekonomiki ◽

10.32609/0042-8736-2005-7-4-18 ◽

2005 ◽

pp. 4-18 ◽

Cited By ~ 5

Author(s):

K. Sonin

Keyword(s):

Property Rights ◽

Institutional Theory ◽

Growth Rates ◽

Rent Seeking ◽

Economic Institutions ◽

Wide Spread ◽

Grass Roots ◽

Protection Systems ◽

Private Protection ◽

The Rich

In unequal societies, the rich may benefit from shaping economic institutions in their favor. This paper analyzes the dynamics of institutional subversion by focusing on public protection of property rights. If this institution functions imperfectly, agents have incentives to invest in private protection of property rights. The ability to maintain private protection systems makes the rich natural opponents of public protection of property rights and precludes grass-roots demand to drive the development of the market-friendly institution. The economy becomes stuck in a bad equilibrium with low growth rates, high inequality of income, and wide-spread rent-seeking. The Russian oligarchs of the 1990s, who controlled large stakes of newly privatized property, provide motivation for this paper.

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Waiting for a New Model of Growth: Russia’s Social and Economic Development in 2013

Voprosy Ekonomiki ◽

10.32609/0042-8736-2014-2-4-32 ◽

2014 ◽

pp. 4-32 ◽

Cited By ~ 7

Author(s):

V. Mau

Keyword(s):

Economic Policy ◽

Economic Development ◽

Economic Performance ◽

Growth Rates ◽

Global Crisis ◽

New Model ◽

Social And Economic Development ◽

Economic Risks

The paper deals with Russian social and economic development in 2013 and prospects for the next year or two. The author discusses the logic and trends of the global crisis started in 2008. This is the basis for further analysis of current Russian economic performance with special emphasis on the problem of growth rates deceleration. Special attention is paid to economic risks and priorities of economic policy.

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Impacts of Paris Agreement on Russian economy

Voprosy Ekonomiki ◽

10.32609/0042-8736-2018-4-76-94 ◽

2018 ◽

pp. 76-94 ◽

Cited By ~ 1

Author(s):

I. A. Makarov ◽

C. Henry ◽

V. P. Sergey

Keyword(s):

Climate Change ◽

Economic Policy ◽

Growth Rates ◽

Paris Agreement ◽

Gdp Growth ◽

Russian Economy ◽

Climate Policies

The paper applies multiregional CGE Economic Policy Projection and Analysis (EPPA) model to analyze major risks the Paris Agreement on climate change adopted in 2015 brings to Russia. The authors come to the conclusion that if parties of the Agreement meet their targets that were set for 2030 it may lead to the decrease of average annual GDP growth rates by 0.2-0.3 p. p. Stricter climate policies beyond this year would bring GDP growth rates reduction in2035-2050 by additional 0.5 p. p. If Russia doesn’t ratify Paris Agreement, these losses may increase. In order to mitigate these risks, diversification of Russian economy is required.

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The Reproduction Vector of the Russian Economy: 1999-2007

Voprosy Ekonomiki ◽

10.32609/0042-8736-2008-4-94-109 ◽

2008 ◽

pp. 94-109 ◽

Cited By ~ 1

Author(s):

D. Sorokin

Keyword(s):

Economic Policy ◽

Human Capital ◽

Growth Rates ◽

Developed Countries ◽

Gdp Per Capita ◽

Real Sector ◽

Russian Economy ◽

Per Capita ◽

The Developed Countries

The problem of the Russian economy’s growth rates is considered in the article in the context of Russia’s backwardness regarding GDP per capita in comparison with the developed countries. The author stresses the urgency of modernization of the real sector of the economy and the recovery of the country’s human capital. For reaching these goals short- or mid-term programs are not sufficient. Economic policy needs a long-term (15-20 years) strategy, otherwise Russia will be condemned to economic inertia and multiplying structural disproportions.

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