Different Methods for Producing Neonatal Undernutrition in Rats Cause Different Brain Changes in the Face of Equivalent Somatic Growth Parameters

1988 ◽  
Vol 10 (3) ◽  
pp. 141-151 ◽  
Author(s):  
J. Tonkiss ◽  
C.A. Cohen ◽  
S.B. Sparber
Author(s):  
Martin E. Atkinson

The development of the facial bones is particularly important in the fields of paediatric dentistry and orthodontics. Dental students and dental practitioners who do not specialize in those subjects should have an appreciation of the subject to be aware of the changes to the face and jaws they are seeing in patients under continuous care as they grow, mature, and age. Human beings increase in both size and complexity during the growth period which lasts from conception until maturity at about 16 to 18 years of age. As we have seen in Chapters 8, 1, 19, 21, and 32, most of the increase in complexity occurs during the pre-embryonic and embryonic phases of prenatal development although changes still occur in many organs and tissues well into post-natal life. Size increase is also rapid prenatally and continues throughout the remainder of the growth period although the growth rate changes. Changes in overall size may occur in mature individuals due to obesity or other pathological conditions but this is not growth. Growth in overall size can be studied by examining the changes with age in easily measured parameters such as height and weight. There are two ways in which such data can be presented as shown in Figure 33.1. A distance curve is the simplest method illustrated in Figure 33.1A by plotting height against age on a graph. Changes in the rate of growth are demonstrated more clearly by plotting the increment in the measurement per unit of time such as the increase in height per year against age; this is a velocity curve shown in Figure 33.1B. You can see in Figure 33.1A that height increases more rapidly around the age of 14; the velocity curve in Figure 33.1B makes the rapid growth at this age much clearer. If distance curves are plotted for different body components, the curves show specific characteristics. The overall growth of the body is accurately indicated by measures of height and weight; these measurements plotted against age produce the somatic growth curve shown in Figure 33.2. Growth is rapid in the prenatal and early post-natal period then begins to slow down after about 4 years of age.


2017 ◽  
Vol 41 (3) ◽  
pp. 558-569
Author(s):  
Francisco Cerna ◽  
Luis A. Cubillos ◽  
Guido Plaza

Somatic growth was studied in the Chilean hake stock off central coast of Chile, through the application of Von Bertalanffy equation (vB) as a non-linear mixed effect model (NLME) on length-at-agedata derived from otolith readings made at Instituto de Fomento Pesquero since 1972. Average growth rates for each year from 1972 to 2009 were estimated. Growth parameters of vB curves were analyzed for three major periods regarding changes in stock biomass (1972-1990, 1991-2003 and 2004-2009). Results indicated that the average growth rate showed inter-annual variations that did not exceed ±15 cm of total length around the historical average of males and females, showing no persistent tendency towards sustained increase or decrease in somatic growth rate. Growth curves obtained with the vB parameters, estimated for the three periods, showed a similar trajectories until age 7 and 8 years, in both male and females. Changes after this age may be a result of a decrease of larger fish removed by the selective effect of fishing, which triggered variations in the fitted curves, but not necessarily changes in somatic growth of these ages in the population. The results demonstrated that the individual growth of hake has not changed significantly since 1972, without observing a density-dependent effect with decreasing abundance.


2012 ◽  
Vol 14 (1) ◽  
pp. 91-99 ◽  

Neuropsychological assessment is a performance-based method to assess cognitive functioning. This method is used to examine the cognitive consequences of brain damage, brain disease, and severe mental illness. There are several specific uses of neuropsychological assessment, including collection of diagnostic information, differential diagnostic information, assessment of treatment response, and prediction of functional potential and functional recovery. We anticipate that clinical neuropsychological assessment will continue to be used, even in the face of advances in imaging technology, because it is already well known that the presence of significant brain changes can be associated with nearly normal cognitive functioning, while individuals with no lesions detectable on imaging can have substantial cognitive and functional limitations.


1990 ◽  
Vol 47 (4) ◽  
pp. 672-681 ◽  
Author(s):  
David W. Welch ◽  
Gordon A. McFarlane

Estimates of size-at-age are commonly reported in fisheries studies, but statistical uncertainty and intrinsic variability in the growth parameters are less frequently examined. We examine these questions using recently-developed statistical methods for quantifying uncertainty and bias in parameter estimates for nonlinear models with independent and additive Gaussian errors. We also describe diagnostic methods to determine when the usual method for examining parameter uncertainty, linearization, is unacceptable. Both our review and our approach to uncertainty are generally applicable to nonlinear estimation, and not solely restricted to growth models. We illustrate our approach with length-at-age data for female Pacific hake (Merluccius productus) from Georgia Strait, British Columbia. Between-year variation in somatic growth seems to be restricted to the two von Bertalanffy growth parameters K and L∞. Mean asymptotic length declined by about 10% since the late 1970's while the parameter K nearly tripled in value. Closer examination showed that the decline in somatic growth was restricted to the maximum size attained. We argue that the changes are most consistent with selective removal of the largest individuals from the population by the fishery, rather than a response of growth rates to either environmental or density-dependent factors.


2017 ◽  
Vol 15 (2) ◽  
Author(s):  
Luzia da S. Lourenço ◽  
Rosa Maria R. da Costa ◽  
Patrícia L. Rondon ◽  
Lúcia A. F. Mateus

ABSTRACT Growth is a fundamental biological process, driven by multiple endogenous (intra-individual) and exogenous (environmental) factors that maintain individual fitness and population stability. The current study aims to assess whether individual, spatial (headwaters and floodplains) and inter-sex variation occurs in the growth of Piaractus mesopotamicus in the Cuiabá River basin. Samples were collected monthly from July 2006 to July 2007, at two areas in the Cuiabá River basin (headwaters and floodplain). Three growth models (individuals; individuals and sex factors; individuals and areas factors) were developed and compared the fish growth parameters using Akaike information criterion (AIC). The best fit to the length-at-age data was obtained by a model that considered individual variation and sex. The theoretical maximum average length ( L∞ ) was 64.99 cm for females, and 63.23 cm for males. Females showed a growth rate (k) of 0.230 yr-1and males of 0.196 yr-1. Thus, could be concluded that individual variability and sex were the main sources of variation in P. mesopotamicus somatic growth parameters.


2020 ◽  
Vol 11 ◽  
pp. 1198-1206
Author(s):  
Rosa Córdoba ◽  
Alfonso Ibarra ◽  
Dominique Mailly ◽  
Isabel Guillamón ◽  
Hermann Suderow ◽  
...  

Currently, the patterning of innovative three-dimensional (3D) nano-objects is required for the development of future advanced electronic components. Helium ion microscopy in combination with a precursor gas can be used for direct writing of three-dimensional nanostructures with a precise control of their geometry, and a significantly higher aspect ratio than other additive manufacturing technologies. We report here on the deposition of 3D hollow tungsten carbide nanowires with tailored diameters by tuning two key growth parameters, namely current and dose of the ion beam. Our results show the control of geometry in 3D hollow nanowires, with outer and inner diameters ranging from 36 to 142 nm and from 5 to 28 nm, respectively; and lengths from 0.5 to 8.9 µm. Transmission electron microscopy experiments indicate that the nanowires have a microstructure of large grains with a crystalline structure compatible with the face-centered cubic WC1− x phase. In addition, 3D electron tomographic reconstructions show that the hollow center of the nanowires is present along the whole nanowire length. Moreover, these nanowires become superconducting at 6.8 K and show high values of critical magnetic field and critical current density. Consequently, these 3D nano-objects could be implemented as components in the next generation of electronics, such as nano-antennas and sensors, based on 3D superconducting architectures.


2011 ◽  
Vol 300 (6) ◽  
pp. R1532-R1542 ◽  
Author(s):  
Eduardo N. Fuentes ◽  
Björn Thrandur Björnsson ◽  
Juan Antonio Valdés ◽  
Ingibjörg Eir Einarsdottir ◽  
Belen Lorca ◽  
...  

The insulin-like growth factor-I (IGF-I) is a key regulator of skeletal muscle growth in vertebrates, promoting mitogenic and anabolic effects through the activation of the MAPK/ERK and the PI3K/Akt signaling pathways. Nutrition also affects skeletal muscle growth, activating intracellular pathways and inducing protein synthesis and accretion. Thus, both hormonal and nutritional signaling regulate muscle mass. In this context, plasma IGF-I levels and the activation of both pathways in response to food were evaluated in the fine flounder using fasting and refeeding trials. The present study describes for the first time in a nonmammalian species that the MAPK/ERK and PI3K/Akt are activated by exogenous circulating IGF-I, as well as showing that the MAPK/ERK pathway activation is modulated by the nutritional status. Also, these results show that there is a time-dependent regulation of IGF-I plasma levels and its signaling pathways in muscle. Together, these results suggest that the nutritionally managed IGF-I could be regulating the activation of the MAPK/ERK and the PI3K/Akt signaling pathways differentially according to the nutritional status, triggering different effects in growth parameters and therefore contributing to somatic growth in fish. This study contributes to the understanding of the nutrient regulation of IGF-I and its signaling pathways in skeletal muscle growth in nonmammalian species, therefore providing insight concerning the events controlling somatic growth in vertebrates.


Author(s):  
Asma Khaldi ◽  
Ines Chater ◽  
Romain Elleboode ◽  
Kélig Mahé ◽  
Nadia Chakroun-Marzouk

Abstract Despite the high commercial value of the striped seabream Lithognathus mormyrus (Linnaeus, 1758) in the Gulf of Tunis, biological data on its age, growth and exploitation rate are lacking. With the aim of estimating growth parameters, 516 individuals, ranging from 6–27.5 cm total length and from 3.5–293.5 g total weight, were collected from the artisanal fishing fleet between February 2014 and July 2016. The somatic growth presented a positive allometry and was described by the equation TW = 6.54 10−3TL3.213. The monthly analysis of the marginal increment of the otoliths revealed that only one annulus was deposited per year. The estimated von Bertalanffy growth parameters were: L∞ = 30.18 cm, k = 0.303 year−1 and t0 = −1.42 years. Total and natural instantaneous rates of mortality were respectively Z = 0.784 year−1 and M = 0.698 year−1. Exploitation rate (E = 0.1) showed that the Gulf of Tunis stock of L. mormyrus is not overexploited. The estimated length class giving highest yield (Lopt) was 17.15 ± 1.71 cm.


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