Episodes Of Growth Research Articles

Seasonal Patterns in White Crappies' Consumption and Growth: Influences of Varying Water Temperatures and Prey Availability

AbstractCrappies Pomoxis spp. are popular sport fishes but often fail to achieve sizes that are acceptable to anglers. While many factors may contribute to episodes of suboptimal growth in crappies, insufficient densities of prey fish and high summer water temperatures (>27°C) have been considered to be key underlying causes. We examined the influences of prey fish size, prey availability, and water temperature on the consumption and growth of white crappies P. annularis (ages 1–3) in three Missouri reservoirs over five successive years. Monthly growth rates were estimated using aging analyses, while consumption was estimated using a bioenergetics model. All age‐groups grew fastest in the reservoir that was warmest but in which prey fish availability was the highest. Diet analyses coupled with bioenergetics modeling suggested that white crappies were able to maintain positive growth rates at temperatures exceeding 27°C by maximizing consumption rates when adequate prey fish resources were available. When sufficient prey fish resources were unavailable, white crappies fed on invertebrates and often ceased growing or lost weight, even during periods with suitable water temperatures. Our study documents the importance of adequate prey fish resources for maintaining positive growth rates of white crappies, especially during periods of adverse temperature conditions.

Zircon U–Pb geochronology and Hf isotopic compositions of the Mesozoic granites in southern Anhui Province, China

Mesozoic magmatism is extensively developed in eastern China along the eastern Asian continental margin, but the geochronological framework is not well understood for each area. In this study, seventy-eight samples were collected from the Mesozoic igneous rocks in south Anhui Province, east-central China, in order to precisely constrain their formation ages and contributions to crustal growth. Zircon U–Pb age determination using ion probe and laser ablation techniques indicate that magmatism in the area can be divided into two separate stages: at 150–136 and 136–120Ma, respectively. The first stage of granitic rocks, not documented in other areas of eastern China, is mostly composed of hornblende-bearing I-type granodiorite and monzogranite, and is considered to be formed by slab-tearing during Pacific subduction. The second stage of magmatism, coeval to that in other areas of eastern China, is characterized by the occurrence of A-type granite and syenite, and their volcanic counterparts, although I-type granitic rocks are also developed locally. These rocks are mostly distributed around and within the fault-controlled volcanic basins, and some are closely related to detachment shearing, indicating their formation in an extensional setting. Zircon Hf isotopic analyses indicate that Archean material might be present in the area, but that the main episode of crustal growth took place during the Mesoproterozoic, with very little juvenile material in the Mesozoic.

Mandibular histology and growth of the nonmammaliaform cynodont Tritylodon

AbstractAn investigation of bone microstructure of nonmammalian therapsids has revealed distinctive signals pertaining to their ontogenetic growth and biology. Until now, histological studies of the nonmammaliaform cynodonts have focused only on postcranial material. Through the examination of micro‐computed tomography (micro‐CT) scans and serial thin sections, the current study provides a novel perspective on the structure and growth of the mandible of Tritylodon, a derived herbivorous cynodont from southern Africa. By tracking histological features across the serial thin sections, trends in relocation and modelling are documented for the growing Tritylodon mandible. For example, during growth, localized changes in the cross‐sectional shape of the mandible occurred. Localized deposits of new lamellar and fibrolamellar bone on the lateral edge indicate widening of the mandible during different episodes of growth. The presence of radial channels indicates the deepening of the mandible at its anterior and posterior ends. The relocation of the paired mental foramina suggests that the mandibular body lengthened mainly in the posterior direction. The medial movement of a posterior postcanine tooth during growth and eruption is recorded in the histology. This histological assessment also documents the presence of Sharpey’s fibres in the cellular cementum of the first incisor, providing novel and unequivocal evidence that it was attached to the Tritylodon jaw by a periodontal ligament. This is the first comprehensive study that uses histological analysis to document the growth dynamics of the mandible of a nonmammalian therapsid, thus providing a unique perspective of localized mandibular growth in a fossil animal.

Age and thermal history of Eo- and Neohimalayan granitoids, eastern Himalaya

Four distinct granitoid suites outcrop across a N–S transect in the eastern Himalaya between the Main Central Thrust (MCT) and the Indus Tsangpo suture. The Arunachal and Tsona leucogranites outcrop, respectively, in the MCT hanging-wall and adjacent the South Tibetan Detachment. Both crystallized at about 19Ma, and appear to be lateral equivalents of the High Himalayan Leucogranites. In the central Tethyan Himalaya, the Dala granitoids form a suite of undeformed plutons emplaced into deformed Tethyan Himalayan Sequence metasediments. In the northern Tethyan Himalaya, the Yala-Xiangbo granitoids are part of an igneous complex in the core of the Yala-Xiangbo dome. Both the Dala and Yala-Xiangbo granitoids have Eocene magmatic ages (44.1±1.2Ma and 42±5Ma, respectively) that are notably older than the vast majority of post-collisional granitoids along the main Himalayan Arc. Pelitic units from the core of the Yala-Xiangbo dome record two episodes of amphibolite-grade metamorphism and monazite growth coinciding with well-documented episodes of Eohimalayan and Neohimalayan metamorphism. The thermochronological histories of the Dala and Yala-Xiangbo units suggest that the eastern Tethyan Himalaya was tectonically quiescent from ca. 40Ma until ca. 15Ma. Miocene exhumation of the Dala and Yala-Xiangbo units, and all North Himalayan Domes studied to date, appears best explained by a structural control, such as concurrent north-directed motion on the Great Counter Thrust. We hypothesize that an extension of the Ninety East Ridge may have been responsible for Eocene high heat-flow beneath the eastern Himalaya and explain the localization of magmatism there.

Early onset of endothelial cell proliferation in coronary thrombi of patients with an acute myocardial infarction: implications for plaque healing

Coronary thrombotic occlusion in ST-segment elevation myocardial infarction (STEMI) patients is often preceded by episodes of progressive growth of the thrombus mass. Similar to wound healing, the organization of thrombus could depend on ingrowth of microvessels in order to stabilize its structure. We investigated the patterns of neovascularization in different stages of coronary thrombus evolution. Thrombectomy materials obtained from STEMI patients were histologically classified according to thrombus age in three groups: fresh (< 1 day), lytic (1-5 days) or organized (> 5 days) thrombi. Forty thrombi of each group were randomly collected. Neovascularization in the thrombi was evaluated histomorphologically and with immunodouble stains to visualize various differentiation antigens of endothelial cells (ECs) and primitive cells. Morphologically, ECs in the coronary thrombi manifested as: single cells, cell clusters or microvessels. CD31+/CD34+ ECs were present in 98% of all the thrombi. In addition, endothelial clusters were found in 63% of the fresh thrombi (< 1 day). CD105+, Ki67+, or C-kit+ ECs (active, proliferating cells) were observed in all the stages, but significantly more in organized thrombi (> 5 days) compared with fresh and lytic ones (< 5 days), and mainly as cell clusters (P ≤ 0.05 for all). CD133+ primitive cells were found only sporadically in 11% of all the samples. EC proliferation is initiated very early, and gradually progresses during the organization process of thrombus after coronary plaque disruption, with only a limited contribution of primitive cells in this process.

The Rise of Large Farms in Land Abundant Countries: Do They Have a Future?

Increased levels and volatility of food prices has led to a surge of interest in large-scale agriculture and land acquisition. This creates challenges for policy makers aiming to establish a policy environment conducive to an agrarian structure to contribute to broad-based development in the long term. Based on a historical review of episodes of growth of large farms and their impact, this paper identifies factors underlying the dominance of owner-operated farm structures and ways in which these may change with development. The amount of land that could potentially be available for expansion and the level of productivity in exploiting available land resources are used to establish a country-level typology. The authors highlight that an assessment of the advantages of large operations, together with information on endowments, can provide input into strategy formulation at the country level. A review of recent cases of land acquisition reinforces the importance of the policy framework in determining outcomes. It suggests that transparency and contract enforcement, recognition of local land rights and ways in which they can be exercised, attention to employment effects and technical viability, and mechanisms to re-allocate land from unsuccessful ventures to more productive entrepreneurs are key areas warranting the attention of policy makers.

The Analysis of Determinant Factors of Poverty And Its Effect Toward Economic Development of Islamic Society : Case Study at Serdang Bedagai Regency At North Sumatera Province

in the last two decades. Indonesia has experienced contrasting episodes in terms of economic growth and changes in the pm erty rate. Prior middle 1980s until middle 19903. Indonesia experienced a high economic growth and a rapid reduction in poverty. During the economic crisis period of 1997-1999, however. the economy contracted substantially and poverty increased signit‘lcantly. wiping out many years of progress. Post-crisis. economic growth slowly recovered. but the poverty rate declined much faster falling to below the pre-crisis level. These contrasting episodes of growth and poverty trends provide the opportunity to empirically assess the relationship between economic development and poverty. Study of this relationships. usually divide the economy into three sectors: agriculture. industry. and services. The mechanism ofthe relationships between economic development and change in poverty must be better understood in order to formulate the most effective strategy for poverty reduction through macroeconomic policy. Therefore. this research tries to examine more specific than previous studies. that is the effect ofdetemiinant factors (such as: level of fonnal education. level ofsocial economic. agriculture land ownership. lslamicjob tradition) ofpm erty toward economic development. This research is done at Serdang Bedagai Regency at North Suimatera Province. The research hypothesis states that [m el of formal education and agriculture land ownership effect economic development significantly. Otherwise. level of social economic and Islamic job tradition insignificantly effect economic developmentKeywords: level of formal education. level of social economic. agriculture land ownership. Islamic job tradition, poverty. economiy development.

The Role of Oscillatory Modes in U.S. Business Cycles

We apply the advanced time-and-frequency-domain method of singular spectrum analysis to study business cycle dynamics in a set of nine U.S. macroeconomic indicators. This method provides a robust way to identify and reconstruct shared oscillations, whether intermittent or modulated. We address the problem of spurious cycles generated by the use of detrending filters and present a Monte Carlo test to extract significant oscillations. Finally, we demonstrate that the behavior of the U.S. economy changes significantly between episodes of growth and recession; these variations cannot be generated by random shocks alone, in the absence of endogenous variability.

The Great Happiness Moderation

This paper shows that within-country happiness inequality has fallen in the majority of countries that have experienced positive income growth over the last forty years, in particular in developed countries. This new stylized fact comes as an addition to the Easterlin paradox, which states that the time trend in average happiness is flat during episodes of long-run income growth. This mean-preserving declining spread in happiness comes about via falls in both the share of individuals who declare low and high levels of happiness. Rising income inequality moderates the fall in happiness inequality, and may even reverse it after some point, for example in the US starting in the 1990s. Hence, if raising the income of all does not raise the happiness of all, it will at least harmonize the happiness of all, providing that income inequality does not grow too much. Behind the veil of ignorance, lower happiness inequality would certainly be considered as attractive by risk-averse individuals.

How Home Loan Modification through the 60/40 Plan Can Save the Housing Sector

Many well-respected economists have suggested plans for mortgage restructuring built on the idea of share appreciation mortgages, which generate rather complex transactions with conflicting interests between the lender and the homeowner. The 60/40 Plan, however, combines several economic principles adapted to the nature of home loans and appears to provide all the benefits but fewer of the drawbacks of many of these programs, including current government programs such as the Home Affordable Refinance (HARP) and Home Affordable Modification (HAMP) programs. For example, HARP home owners must service the entire principal balance and meet additional eligibility restrictions that are not warranted by economic considerations. In contrast, the 60/40 Plan provides for affordable monthly pay ments by restructuring the debt into two parts, has relatively minor eligibility requirements, and creates household incentives to maintain the property. Failure to address the current financing needs of the housing market may result in a decapitalization of the banking sector, lost potential house value for many homeowners through foreclosure, and an extended episode of low growth for the U.S. economy. (JEL E44, E52, G01)

The Great Happiness Moderation

This paper shows that within-country happiness inequality has fallen in the majority of countries that have experienced positive income growth over the last forty years, in particular in developed countries. This new stylized fact comes as an addition to the Easterlin paradox, which states that the time trend in average happiness is flat during episodes of long-run income growth. This mean-preserving declining spread in happiness comes about via falls in both the share of individuals who declare low and high levels of happiness. Rising income inequality moderates the fall in happiness inequality, and may even reverse it after some point, for example in the US starting in the 1990s. Hence, if raising the income of all does not raise the happiness of all, it will at least harmonize the happiness of all, providing that income inequality does not grow too much. Behind the veil of ignorance, lower happiness inequality would certainly be considered as attractive by risk-averse individuals.

Determinants of Growth Spells: Is Africa Different?

Do growth spells in Africa end because of bad realizations of the same factors that influence growth spells in the rest of the world, or because of different factors altogether? To answer this question, we examine determinants of growth spells in Africa and the rest of the world using Bayesian Mode Averaging techniques for proportional hazards models. We define growth spells as periods of sustained growth episodes between growth accelerations and decelerations and then relate the probability that a growth spell ends to various determinants including exogenous shocks, physical and human capital, macroeconomic policy, and sociopolitical factors. Our analysis suggests that determinants of growth spells in Africa are different from those in the rest of the world. The majority of the identified robust determinants have a distinct impact in only one of the two samples: initial income, terms of trade, exchange rate undervaluation and inflation, influence spells only in the world sample, while openness and droughts seem to only affect Africa. In addition, a few common determinants - proxies for human and physical capital and changes in the world interest rate - have very different marginal effects in the two samples.

Determinants of Growth Spells: Is Africa Different?

Do growth spells in Africa end because of bad realizations of the same factors that influence growth spells in the rest of the world, or because of different factors altogether? To answer this question, we examine determinants of growth spells in Africa and the rest of the world using Bayesian Mode Averaging techniques for proportional hazards models. We define growth spells as periods of sustained growth episodes between growth accelerations and decelerations and then relate the probability that a growth spell ends to various determinants including exogenous shocks, physical and human capital, macroeconomic policy, and sociopolitical factors. Our analysis suggests that determinants of growth spells in Africa are different from those in the rest of the world. The majority of the identified robust determinants have a distinct impact in only one of the two samples: initial income, terms of trade, exchange rate undervaluation and inflation, influence spells only in the world sample, while openness and droughts seem to only affect Africa. In addition, a few common determinants - proxies for human and physical capital and changes in the world interest rate - have very different marginal effects in the two samples.

Credit Growth and Bank Soundness: Fast and Furious?

This paper examines risks to bank soundness associated with rapid credit growth in a large set of countries. At a conceptual level, bank soundness may weaken during episodes of fast credit growth because of capacity constraints or competitive pressures as banks make riskier loans in order to expand their market shares. Credit growth may also be affected by bank soundness, however, the sign of the effect is ambiguous: it may be positive because sounder banks have more capacity or it may be negative because less sound banks become more aggressive in a last effort to survive. Using bank-level information in 90 countries between 1995 and 2005, we analyze the relationship between credit growth and bank soundness in an econometric setting that takes into account the potential two-way causality. We find limited evidence that credit growth deteriorates bank soundness. Yet, while sounder banks tend to grow faster at moderate-growth periods, credit growth becomes less dependent on soundness during credit booms. These findings shed some light on why, historically, credit booms are often associated with financial crises.

Erosion/accretion patterns and multiple beach cusp systems on a meso-tidal, steeply-sloping beach

This study examines daily variations in intertidal topography and beach cusps on a meso-tidal, steeply sloping beach during a five-month period. The observations are based on coastal imagery and frequent topographic surveys and are extracted from patterns of contours positioned 1 and 3m above MSL (lower/higher beach-face, respectively). The intertidal topography was very sensitive to variations in the wave regime, triggering rapid transitions from erosive to accretive states and vice versa, as well as transformations of the cusp systems, often involving severe horn erosion and beach-face scarping. Distinct beach cusp systems were observed at different levels of the beach, with their evolution being controlled by: (i) wave forcing; (ii) tidal modulation of the wave power at different levels of the beach; and (iii) interactions between the existing beach cusp systems. The lower beach-face rhythmical patterns changed constantly and merged with the upper beach-face cuspate features, typically when the significant wave height exceeded Ho>1.5m. The upper beach-face pattern was persistent during the monitoring period, re-emerging with similar spacing and alignment, despite being eroded during energetic events; this persistence is also maintained by the interactions between swash and irregularities (e.g. embayments) in the dune/backshore morphology. The spacing of the observed beach cusps ranged from λc,min=8m to λc,max=67m; these values were underestimated by the edge wave and self-organization theories and were better predicted by the Sunamura (2004) formula. Beach cusp growth was linked to breaker angles of near-normal incidence and narrow-banded frequency wave conditions. Bay infilling was found to be the most dominant cusp reduction mechanism for larger features (λc>30m), while smaller features vanished during erosive conditions. The most intense cusp growth episodes were linked to accretive conditions, while larger features were shown to emerge during more energetic, erosion events. These findings highlight the need for more longer-term observations of diverse beach morphologies to formulate a global theory regarding beach cusp formation and evolution.

Low-Al and high-Al trondhjemites in the Huai’an Complex, North China Craton: Geochemistry, zircon U–Pb and Hf isotopes, and implications for Neoarchean crustal growth and remelting

Voluminous tonalite–trondhjemite–granodiorite (TTG) magmas were emplaced in the Huai’an Complex of North China Craton (NCC) during the Neoarchean. Here we present the geochemical characteristics of these rocks and identify low-Al (LAl) and high-Al (HAl) types of trondhjemites within the TTG suite. The LAl group displays high silica (SiO2=77–80wt.%), and low Al2O3 contents (11.06–11.89wt.%), a strongly peraluminous (A/CNK=1.16 and 1.19) composition and enrichment in HREE (LaN/YbN=4 and 5, GdN/YbN=0.35 and 0.9). Their low Rb (13 and 28ppm), Th (0.3 and 7.0ppm), relatively high Na2O/K2O values (3.6 and 4.1) and MgO (0.63 and 0.68wt.%) with moderately high Mg# (36 and 53), suggest crystallization from a primitive source. The HAl group is characterized by relatively low SiO2 (67.22–71.57wt.%) and high Al2O3 contents (16.35–16.41wt.%) with trace element contents and distribution patterns closely comparable to those of Archean high-Al TTGs. Our geochemical data do not favor a direct genetic link between the LAl and HAl trondhjemite groups. The zircon U–Pb data reveal that the LAl and HAl groups represent coeval intrusions at ca. 2.55–2.5Ga. In situ analysis of Hf isotopes in the zircons (εHf=+5.6 to +10, and TDM=2462–2595Ma), together with the geochemical features of the low-Al trondhjemites suggest that they were generated under relatively low pressure (<8kbar), through low degree partial melting of a newly accreted amphibolitic crust. Taking into consideration the contemporaneous (2.55–2.50Ga) high-Al TTGs widely exposed in the Huai’an Complex, we suggest that the low-Al trondhjemites were formed by intraplating of mantle-derived magmas, and the coeval high-Al TTGs were produced by partial melting of a thickened lower crust, triggered by underplating. Our study attests to a major episode of Neoarchean crustal growth in the NCC, and remelting induced by underplating and intraplating of mantle-derived magmas.

Asymmetry in growth and decay of the geomagnetic dipole

The geodynamo in Earth's core is responsible for magnetic field changes on diverse timescales, including numerous enigmatic reversals of the dipole field polarity. Understanding the physical processes driving them is an active area of investigation via both paleomagnetic work and numerical simulations of the geodynamo. Some previous studies on geomagnetic field intensity detected a sawtooth pattern of intensity around reversals: a gradual decay in field strength preceding a reversal followed by rapid growth afterwards. Here we characterize distinct statistical properties for increasing and decreasing dipole strength over the past two million years. Examining the geomagnetic field and its time derivative on a range of time scales reveals that for periods longer than about 25 ky there is a clear asymmetry in the statistical distributions for growth versus decay rates of the dipole strength. At 36 ky period, average growth rate is about 20% larger than the decay rate, and the field spends 54% of its time decaying, but only 46% growing. These differences are not limited to times when the field is reversing, suggesting that the asymmetry is controlled by fundamental physical processes underlying all paleosecular variation. The longer decay cycle might suggest the possibility of episodic periods of subcritical dynamo activity where the field is dominated by diffusive processes, followed by transient episodes of strong growth of the axial dipole. However, our work finds no clear separation of timescales for the influence of diffusive and convective processes on dipole moment: both seem to play an important but asymmetric role on the 25–150 ky timescale.

The role of growth hormone in growth, lipid homeostasis, energy utilization and partitioning in rainbow trout: Interactions with leptin, ghrelin and insulin-like growth factor I

The growth-promoting effects of in vivo growth hormone (GH) treatment were studied in relation to size and lipid content of energy stores including liver, mesentery, white muscle and belly flap in rainbow trout. In order to elucidate endocrine interactions and links to regulation of growth, adiposity and energy metabolism, plasma levels of GH, insulin-like growth factor I (IGF-I), leptin (Lep) and ghrelin, were assessed and correlated to growth and energy status. In addition tissue-specific expression of lepa1 mRNA was examined. Juvenile rainbow trout were implanted with sustained-release bovine GH implants and terminally sub-sampled at 1, 3 and 6 weeks. GH increased specific growth rate, reduced condition factor (CF) and increased feed conversion efficiency resulting in a redistribution of energy stores. Thus, GH decreased mesenteric (MSI) and liver somatic index (LSI). Lipid content of the belly flap increased following GH-treatment while liver and muscle lipid content decreased. Independent of GH substantial growth was accompanied by an increase in muscle lipids and a decrease in belly flap lipids. The data suggest that the belly flap may function as an energy buffering tissue during episodes of feeding and lean growth. Liver and muscle lipids were positively correlated to body weight, indicating a size-dependent change in adiposity. Hepatic lepa1 mRNA positively correlated to MSI and CF and its expression decreased following GH treatment, coinciding with decreased hepatic lipid content. Plasma Lep was positively correlated to MSI and belly flap lipid content, suggesting that Lep may communicate energy status. In summary, the observed GH tissue-specific effects on lipid metabolism in rainbow trout highlight the complex physiology of the energy reserves and their endocrine control.

Venezuela’s Growth Experience

The standard of living, measured as gross domestic product (GDP) per capita, increased dramatically in Venezuela relative to that of the United States from 20 percent in 1920 to 90 percent in 1958, but since then has collapsed to around 30 percent nowadays. What explains these remarkable growth and collapse episodes? Using a standard development accounting framework, we show that the growth episode is mainly accounted for by an increase in capital accumulation and knowledge transfer associated with the foreign direct investment in the booming oil industry. The collapse episode is accounted for equally by a fall in total factor productivity and in capital accumulation. We analyze Venezuela during the collapse episode in the context of a model of heterogeneous production units were policies and institutions favour unproductive in detriment of more productive activities. These policies generate misallocation, lower TFP, and a decline in capital accumulation. We show in the context of an heterogeneous-establishment growth model that distortionary policies can explain between 80 to 95 percent of the current differences in TFP, capital accumulation, and income per capita between Venezuela and the United States.

VENEZUELA'S GROWTH EXPERIENCE

The standard of living, measured as gross domestic product (GDP) per capita, increased dramatically in Venezuela relative to that of the United States from 20 percent in 1920 to 90 percent in 1958, but since then has collapsed to around 30 percent nowadays. What explains these remarkable growth and collapse episodes? Using a standard development accounting framework, we show that the growth episode is mainly accounted for by an increase in capital accumulation and knowledge transfer associated with the foreign direct investment in the booming oil industry. The collapse episode is accounted for equally by a fall in total factor productivity and in capital accumulation. We analyze Venezuela during the collapse episode in the context of a model of heterogeneous production units were policies and institutions favour unproductive in detriment of more productive activities. These policies generate misallocation, lower TFP, and a decline in capital accumulation. We show in the context of an heterogeneous-establishment growth model that distortionary policies can explain a large portion of the current differences in TFP, capital accumulation, and income per capita between Venezuela and the United States.