scholarly journals Brain Size of the African Grasscutter (Thryonomys Swinderianus, Temminck, 1827) at Defined Postnatal Periods

2017 ◽  
Vol 61 (4) ◽  
pp. 5-11 ◽  
Author(s):  
C. S. Ibe ◽  
S. O. Salami ◽  
N. Wanmi
Keyword(s):  
Cognitive Ability ◽  
Brain Size ◽  
Natural Habitat ◽  
Brain Weight ◽  
Strong Positive Correlation ◽  
Positive Correlation ◽  
Thryonomys Swinderianus ◽  
Physiological Studies ◽  
The Difference ◽  
The Brain

Abstract As a sequel to the current advancement in ethology, this study was designed to provide information on the brain size of the African grasscutter at specific postnatal periods and to extrapolate these findings to the behaviour of the rodent in its natural habitat. Brain samples were extracted from African grasscutter neonates on postnatal day 6, juveniles on postnatal day 72 and adults on postnatal day 450 by basic neuro-anatomical techniques. The weight, volume and dimensions of the brain samples were determined in absolute and relative terms. Their encephalisation quotient was also computed. There was a very strong positive correlation between nose-rump length and brain length in the neonates. The relative brain weight of neonates, juveniles and adults were 3.84 ± 0.12 %, 2.49 ± 0.07 % and 0.44 ± 0.03 %, respectively. The differences were significant (P < 0.05). The encephalisation quotient of juveniles was 1.62 ± 0.03 while that of the adult was 0.49 ± 0.02. The difference was significant (P < 0.05). The results were extrapolated to the animal’s cognitive ability, and compared with other rodents. It was concluded that the juvenile African grasscutter may have higher cognitive ability than the adult rodent, thus, juveniles should be preferred in physiological studies of memory and cognition.

On the anatomic relation of choroid plexus to brain: a comparative study

1980 ◽  
Vol 238 (1) ◽  
pp. R76-R81 ◽  
Author(s):  
H. F. Cserr ◽  
M. Bundgaard ◽  
J. K. Ashby ◽  
M. Murray
Keyword(s):  
Choroid Plexus ◽  
Brain Volume ◽  
Brain Size ◽  
Ventricular Volume ◽  
Brain Weight ◽  
Air Breathing ◽  
Original Proposal ◽  
Adaptive Value ◽  
Choroid Plexuses ◽  
The Brain

The size of choroid plexuses and cerebral ventricles relative to brain varies widely among vertebrates. The functional significance of this variability has attracted little attention since Herrick's original proposal that large choroid plexuses might enhance oxygen delivery to the brain and therefore be of adaptive value in the transition of vertebrates from water to air breathing. We compared choroid plexus and brain weight or ventricular and brain volume in 40 species from nine vertebrate groups. Both choroid plexus weight and ventricular volume were unrelated to brain size. Plexus weight ranged from 0 to 5.2% of brain weight and ventricular volume from 0.9 to 132% of brain volume. Amid this diversity the dipnoans, chondrosteans, holosteans, amphibians, and crossopterygian examined in this study are exceptional in uniformly having large plexuses. The adaptive significance of large choroid plexuses may lie in the presence of specific homeostatic mechanisms and their role in the response to the increases in PCO2 that accompany the transition to air breathing.

scholarly journals Effect of Soluble Salt Loss via Spring Water on Irrigation-Induced Landslide Deformation

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2889
Author(s):  
Zonglin Zhang ◽  
Runqiang Zeng ◽  
Xingmin Meng ◽  
Yi Zhang ◽  
Shufen Zhao ◽  
...  
Keyword(s):  
Large Scale ◽  
Field Investigation ◽  
Spring Water ◽  
Gansu Province ◽  
Soluble Salt ◽  
Strong Positive Correlation ◽  
Positive Correlation ◽  
Landslide Deformation ◽  
The Difference ◽  
Sbas Insar

Landslide exposes the previously blocked groundwater discharge. High concentrations of soluble salt form salt sinters that can be observed near discharge passages. Based on existing laboratory investigation results of soil leaching and shearing reported in the literature, the effect of the soluble salt loss via spring water on irrigation-induced landslide deformation was studied under large-scale conditions. During our field investigation of landslides in the Heitai terrace of the Yellow River’s upper reaches in Gansu Province, China, 35 spring outlets were found, and the Heitai terrace was divided into five subareas, based on the difference in spring flow. Deformation data for the terrace were obtained by small baseline subset technology (SBAS-InSAR). These data were analyzed in combination with the amount of soluble salt loss, to explore the correlation between the deformation of the landslide and the soluble salt loss in the loess irrigation area. The results showed that the cumulative deformation and the loss of soluble salt were increasing continuously in the terrace. Although the increasing intensity of each subarea was different, the changing intensity of the two during the corresponding monitoring period was highly consistent. The statistical analysis revealed a strong positive correlation between the accumulated loss of soluble salt via spring water and the accumulated displacement of the terrace edge (p < 0.01). After the slope k between the two was tested by the Grubbs test and t-test, the k was no abnormality (α = 0.05) and difference (Sig > 0.05), further providing the basis for confirming the existence of this positive correlation. When the loss of soluble salt in rock and soil increased gradually, the accumulated deformation of the terrace edge also increased continuously. The findings of this study are of great significance for understanding the formation mechanism of landslides and the identifying landslide revival in irrigation areas of the Loess Plateau.

scholarly journals Seasonal mass-balance gradients in Norway

2005 ◽  
Vol 51 (175) ◽  
pp. 601-606 ◽  
Author(s):  
L.A. Rasmussen ◽  
L.M. Andreassen
Keyword(s):  
Mass Balance ◽  
Strong Positive Correlation ◽  
Vertical Profiles ◽  
Altitude Range ◽  
Positive Correlation ◽  
The World ◽  
The Difference ◽  
A Site

AbstractPreviously discovered regularity in vertical profiles of net balance, bn(z), on ten glaciers in Norway also exists in profiles of both winter, bw(z), and summer, bs(z), seasonal balances. All three profiles, unlike those of many glaciers elsewhere in the world, are remarkably linear. Variations of gradients, dbw/dz and dbs/dz, from year to year are small and correlate poorly with glacier-total balances bw and bs. Glacier-to-glacier correlation is weak for both gradients but is strongly positive for bw and bs. There are two direct consequences of these properties of the gradients that apply to both seasonal balances bw and bs. First, because db/dz varies so little from year to year, the difference in balance, ∆b, from year to year is nearly the same over the entire glacier, except near the top and bottom of its altitude range. Therefore, balance at a site near the middle of the altitude range of the glacier correlates very well with glacier-total balance. Second, this correlation, combined with the strong positive correlation of balance from glacier to glacier, is the reason balance at one altitude on one glacier correlates well with glacier-total balance at other nearby glaciers.

scholarly journals Revisiting the social brain hypothesis: contest duration depends on loser’s brain size

2018 ◽  
Author(s):  
Wouter van der Bijl ◽  
Séverine D. Buechel ◽  
Alexander Kotrschal ◽  
Niclas Kolm
Keyword(s):  
Social Competence ◽  
Cognitive Ability ◽  
Brain Size ◽  
Empirical Support ◽  
Group Living ◽  
Brain Morphology ◽  
Selection Line ◽  
Behavioral Mechanism ◽  
The Social ◽  
The Brain

AbstractBackgroundBrain size is expected to evolve by a balance between cognitive benefits and energetic costs. Several influential hypotheses have suggested that large brains may be especially beneficial in social contexts. Group living and competition may pose unique cognitive challenges to individuals and favor the evolution of increased cognitive ability. Evidence comes from comparative studies on the link between social complexity and brain morphology, but the strength of empirical support has recently been challenged. In addition, the behavioral mechanisms that would link cognitive ability to sociality are rarely studied. Here we take an alternative approach and investigate experimentally how brain size can relate to the social competence of individuals within species, a problem that so far has remained unresolved. We use the unique guppy brain size selection line model system to evaluate whether large brains are advantageous by allowing individuals to better assess their performance in a social contest situation. Based on theoretical literature, we predict that contest duration should depend on the brain size of the loser, as it is the capitulation of the losing individual that ends the fight.ResultsFirst, we show that studying the movement of competitors during contests allows for precise estimation of the dominance timeline in guppies, even when overt aggression is typically one-sided and delayed. Second, we staged contests between pairs of male that had been artificially selected for large and small relative brain size, with demonstrated differences in cognitive ability. We show that dominance was established much earlier in contests with large-brained losers, whereas the brain size of the winner had no effect. Following our prediction, large-brained individuals gave up more quickly when they were going to lose.ConclusionsThese results suggest that large-brained individuals assess their performance in contests better and that social competence indeed can depend on brain size. Conflict resolution may therefore be an important behavioral mechanism behind macro-evolutionary patterns between sociality and brain size. Since conflict is ubiquitous among group-living animals, the possible effects of the social environment on the evolution of cognition may be more broadly applicable than previously thought.

scholarly journals Brain weights in adult africans

2017 ◽  
Vol 34 (04) ◽  
pp. 223-225 ◽  
Author(s):  
A. Salami ◽  
M. Ajani ◽  
I. Orhorho ◽  
G. Ogun ◽  
A. Adeoye ◽  
...  
Keyword(s):  
Early Adulthood ◽  
Age Groups ◽  
The Elderly ◽  
Brain Weight ◽  
Significant Difference ◽  
The Central Nervous System ◽  
The Mean ◽  
The Difference ◽  
Autopsy Specimens ◽  
The Brain

Abstract Introduction: The average brain weight of adult humans, using Caucasian figures, is said to be between 1300g to 1400g. Few studies have however been done to make actual evaluations of brain weights in adult Africans. This study seeks to examine the weight of brains from people of African descent with respect to variations in sex and age in decades using autopsy specimens. Materials and Methods: Analysis of the weight of brains removed from both male and female adult patients during fresh autopsy of their bodies in our center over a ten year period was done. The study criteria required non-involvement of the central nervous system in the cause of death. The brains were grouped based on age in decades and further grouped into early, middle and late age groups. Descriptive statistical analysis was done using SPSS 20 statistics software. Results: A total of one hundred and sixteen brains were included in the study and the mean brain weight was 1280g with a range between 1015g to 1590g. There was no statistically significant difference in the mean brain weight of the different age groups. The average male brain was heavier than those of females and the difference was statistically signiicant. Conclusion: The brain weight of adult Africans in our study is similar to that seen in Caucasians. There is no statistically significant difference in the brain weight of adults from early adulthood to the elderly adults. Male adults have statistically heavier brains than the females.

Relationship between citation counts and Mendeley readership metrics

2016 ◽  
Vol 117 (3/4) ◽  
pp. 229-238 ◽  
Author(s):  
Rishabh Shrivastava ◽  
Preeti Mahajan
Keyword(s):  
Strong Positive Correlation ◽  
Bibliometric Indicators ◽  
Content Type ◽  
Positive Correlation ◽  
Time Periods ◽  
Scopus Database ◽  
Citation Counts ◽  
The Difference ◽  
Number Of Citations ◽  
The Relationship

Purpose – Social media has given way for the development of various new altmetric indicators. Mendeley readership count is one such indicator. The purpose of this paper is twofold. First, the paper aims to investigate the relationship between citation counts and Mendeley readership counts. The paper also evaluates the relationship between Mendeley readership metrics for two different time periods, thereby investigating its nature as an altmetric indicator. Design/methodology/approach – Data were collected using the Scopus database. Top 100 papers in Physics published during 2005 as well as in 2010 that received the largest number of citations were selected. Mendeley readership data were collected using Mendeley readership statistics for documents indexed in Scopus. For establishing a relationship between citation counts and Mendeley readership, correlation was calculated between the citations in Scopus database and Mendeley readership. The difference in Mendeley readership for different time periods was also investigated. Findings – The paper showed that for both the years, Mendeley readership counts were in positive correlation with citation counts. For the year 2010, it was found that Mendeley readership counts were in strong positive correlation with citation counts, whereas for 2005, they were in moderate positive correlation. Research limitations/implications – One of the limitations of this paper is that with time more scientists and researchers may join Mendeley causing various changes in data and giving different results. Also, the paper has focused on the highly cited papers in Physics. Originality/value – Very few studies have been conducted in the area of altmetrics, as it is a comparatively new and emerging field of research. The findings of this paper offer insights to the question whether Mendeley readership counts can be used as an alternative to traditional sources of bibliometric indicators like citations, h-index, etc. The paper also evaluates the difference in the nature of traditional bibliometric indicators and Mendeley readership counts.

scholarly journals Utility of Nuclear Morphometry in Predicting Grades of Diffusely Infiltrating Gliomas

ISRN Oncology ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-8
Author(s):  
Dibyajyoti Boruah ◽  
Prabal Deb
Keyword(s):  
Major Axis ◽  
Strong Positive Correlation ◽  
Nuclear Area ◽  
Tumour Grade ◽  
Neoplastic Tissue ◽  
Mean Values ◽  
Positive Correlation ◽  
The Mean ◽  
The Difference ◽  
Immense Potential

Introduction. The ability to reliably differentiate neoplastic from nonneoplastic specimen and ascertain the tumour grade of diffusely infiltrating gliomas (DIGs) is often challenging. Aims and Objective. To evaluate utility of image morphometry in identifying DIG areas and to predict tumour grade. Materials and Methods. Image morphometry was used to analyze the following nuclear features of 30 DIGs and 10 controls (CG): major axis of nucleus (MAJX), minor axis of nucleus (MINX), nuclear area (NA), nuclear perimeter (NP), nuclear roundness (NR), nuclear density (ND), and percentage of total nuclear area (%TNA). Results. Statistically significant differences in all parameters, except NR, were observed between all groups, with strong positive correlation with tumour grade (r>0.7). The mean values were maximum for HGG and minimum for CG. For NR, the difference between CG/HGG was statistically significant, unlike CG/LGG and LGG/HGG. It was observed that NA distributions for CG were nearly Gaussian type with smaller range, while gliomas displayed erratic pattern with larger range. NA and NP exhibited strong positive correlation with ND. Conclusion. Image morphometry has immense potential in being a powerful tool to distinguish normal from neoplastic tissue and also to differentiate LGG from HGG cases, especially in tiny stereotactic biopsies.

scholarly journals Asymmetry and sexual dimorphism of the medial frontal gyrus visible surface in humans

2010 ◽  
Vol 67 (2) ◽  
pp. 123-127
Author(s):  
Goran Spasojevic ◽  
Zlatan Stojanovic ◽  
Dusan Suscevic ◽  
Slobodan Malobabic ◽  
Saso Rafajlovski ◽  
...  
Keyword(s):  
Sexual Dimorphism ◽  
Brain Size ◽  
Genetic Studies ◽  
Brain Hemispheres ◽  
Morphological Asymmetry ◽  
Medial Frontal Gyrus ◽  
The Difference ◽  
The Right ◽  
The Brain ◽  
Human Nervous System

Background/Aim. Studies of visible (extrasulcal) surface of the brain hemispheres are not feasible for measurements of the brain size, but are valuable for analysis and quantification of sexual dimorphism and/or asymmetries of the human brain. Morphological and morphometric investigations of the brain may contribute in genetic studies of the human nervous system. The aim of this study was to determine and to quantify sexual dimorphism and the right/left morphological asymmetry of the visible surface of medial frontal gyrus (gyrus frontalis medialis - GFM). Methods. Measurements and analysis of the visible surface of GFM were done on 84 hemispheres (42 brains from the persons of both sexes: 26 males and 16 females, 20-65 years of age). After fixation in 10% formalin and dissection, digital morphometric measurements were performed. We studied these in relation to the side of the hemisphere and the person's sex. Standardized digital AutoCAD planimetry of the visible surface of GFM was enabled by the use of coordinate system of intercommissural line. Results. In the whole sample, the visible surface of the right GFM (21.39 cm2) was statistically significantly greater (p < 0.05) than the left GFM (18.35 cm2) indicating the right/left asymmetry of the visible surface of GFM. Also, the visible surface of the right GFM in the males (22.66 cm2) was significantly greater (p < 0.05) than in the females (19.35 cm2), while the difference in size of the left GFM between the males and the females was not significant (p > 0.05). Conclusion. Morphological analysis of visible surface of GFM performed by digital planimetry showed sexual dimorphism of the visible surface and the presence of right/left asymmetry of GFM.

Sex Differences in Childhood Associations between DNA Markers and General Cognitive Ability

2007 ◽  
Vol 28 (3) ◽  
pp. 161-164 ◽  
Author(s):  
Rosalind Arden ◽  
Nicole Harlaar ◽  
Robert Plomin
Keyword(s):  
Sex Differences ◽  
Single Nucleotide Polymorphisms ◽  
Cognitive Ability ◽  
Dna Markers ◽  
Community Sample ◽  
Nucleotide Polymorphisms ◽  
General Cognitive Ability ◽  
Single Nucleotide ◽  
The Difference

Abstract. An association between intelligence at age 7 and a set of five single-nucleotide polymorphisms (SNPs) has been identified and replicated. We used this composite SNP set to investigate whether the associations differ between boys and girls for general cognitive ability at ages 2, 3, 4, 7, 9, and 10 years. In a longitudinal community sample of British twins aged 2-10 (n > 4,000 individuals), we found that the SNP set is more strongly associated with intelligence in males than in females at ages 7, 9, and 10 and the difference is significant at 10. If this finding replicates in other studies, these results will constitute the first evidence of the same autosomal genes acting differently on intelligence in the two sexes.

The Strong Positive Correlation between Factor VII Clotting Activity Using Bovine Thromboplastin and the Activated Factor VII Level

1995 ◽  
Vol 73 (03) ◽  
pp. 429-434 ◽  
Author(s):  
Kazuomi Kario ◽  
Takefumi Matsuo ◽  
Reiko Asada ◽  
Toshiyuki Sakata ◽  
Hisao Kato ◽  
...  
Keyword(s):  
Risk Factor ◽  
Bovine Brain ◽  
Factor Vii ◽  
Rabbit Brain ◽  
Strong Positive Correlation ◽  
Chromogenic Substrate ◽  
Moderate Correlation ◽  
Positive Correlation ◽  
Activated Factor Vii

SummaryWe compared factor VII clotting activity (FVIIc) assays using different thromboplastins to determine which is the most sensitive for activated FVII (FVIIa) or for FVII antigen (FVIIag). FVIIc levels were measured using thromboplastins derived from bovine brain (FVIIc Bov), human placenta (FVIIc Hum), and rabbit brain (FVIIc Rab). FVIIa levels were measured by fluorogenic assays using human soluble tissue factor (rsTF) or bovine rsTF. We also measured FVII activity by an amidolytic assay (FVIIc:am Hum) using human thromboplastin and a chromogenic substrate for thrombin. FVIIag levels were determined by ELISA. In the FVIIa assay, the reaction time obtained from using bovine rsTF was shorter than that with human rsTF, suggesting that the interaction of plasma FVIIa with bovine rsTF was stronger than with human rsTF. The plasma FVIIa levels measured using human rsTF and bovine rsTF were almost the same (r=0.947, p<0.0001). Among the three FVIIc assays, FVIIc Bov had the strongest positive correlation with the plasma FVIIa level (r=0.886, p<0.000l), but had no correlation with FVIIag. An increase of 1 ng/ml in the plasma FVIIa level yielded a 27.9% increase of FVIIc Bov. Plasma FVIIc Hum and FVIIc:am Hum showed moderate correlations with both FVIIa (r=0.520, p<0.02 and r=0.569, p<0.01, respectively) and FVIIag (r=0.438, p<0.05 and r=0.468, p<0.05, respectively). FVIIc Rab had the lowest correlation with FVIIa (r=0.367, p<0.1), but had a moderate correlation with FVIIag (r=0.436, p<0.05). After in vitro cold activation, FVIIc Bov levels increased the most and FVIIc:am levels showed the least change. These findings indicate that consideration of the thromboplastin used for assay is necessary when assessing the clinical significance of FVII activity as a cardiovascular risk factor.

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