scholarly journals Energetic constraints on an early developmental stage: a comparative view

2007 ◽  
Vol 4 (1) ◽  
pp. 123-126 ◽  
Author(s):  
James F Gillooly ◽  
Gustavo A Londoño ◽  
Andrew P Allen

Biologists have long sought a means by which to quantify similarities and differences in embryonic development across species. Here we present a quantitative approach for predicting the timing of developmental events based on principles of allometry and biochemical kinetics. Data from diverse oviparous species support model predictions that most variation in the time required to reach one early developmental stage—the time to first heartbeat—is explained by the body size and temperature dependence of metabolic rate. Furthermore, comparisons of this stage with later developmental stages suggest that, after correcting for size and temperature, the relationship of metabolic rate to the rate of embryogenesis is approximately invariant across taxonomic groups and stages of ontogeny.

2001 ◽  
Vol 281 (1) ◽  
pp. H411-H421 ◽  
Author(s):  
Heinrich Sauer ◽  
Tobias Theben ◽  
Jürgen Hescheler ◽  
Michael Lindner ◽  
Mathias C. Brandt ◽  
...  

In embryonic stem (ES) cell-derived cardiomyocytes, spontaneous Ca2+ sparks representing Ca2+ release through ryanodine receptor (RyR) channels were characterized and correlated to the expression of RyRs as well as the Ca2+ load of the sarcoplasmic reticulum (SR). In very early developmental stage (VEDS) cardiac precursor cells, global intracellular Ca2+ concentration ([Ca2+]i) fluctuations occurred, whereas Ca2+ sparks and contractions were absent. In early developmental stages (EDS), contractions as well as Ca2+sparks were obvious. During the further differentiation to late developmental stage (LDS) cardiomyocytes, a marked increase in the frequency of global [Ca2+]i transients, the amplitude and the frequency of Ca2+ sparks, as well as the expression of RyRs and the volume of RyR-positive SR, was observed. Furthermore, the caffeine-releasable SR Ca2+ load was elevated in LDS compared with EDS cardiomyocytes. A high-Ca2+ solution raised spark frequency as well as amplitude in EDS cardiomyocytes to the levels of LDS cardiomyocytes. The characteristics of Ca2+ sparks occurring in cardiomyocytes differentiated from ES cells may be governed by the Ca2+ load of the SR and/or the density of RyRs.


2017 ◽  
Vol 59 (2) ◽  
pp. 014-021
Author(s):  
Saya K. Koyshibaeva ◽  
◽  
Shokhan A. Alpeyisov ◽  
Evgeniy V. Fedorov ◽  
Nina S. Badryzlova ◽  
...  

Author(s):  
Joshua S. Walden

The book’s epilogue explores the place of musical portraiture in the context of posthumous depictions of the deceased, and in relation to the so-called posthuman condition, which describes contemporary changes in the relationship of the individual with such aspects of life as technology and the body. It first examines Alfred Hitchcock’s Vertigo to view how Bernard Herrmann’s score relates to issues of portraiture and the depiction of the identity of the deceased. It then considers the work of cyborg composer-artist Neil Harbisson, who has aimed, through the use of new capabilities of hybridity between the body and technology, to convey something akin to visual likeness in his series of Sound Portraits. The epilogue shows how an examination of contemporary views of posthumous and posthuman identities helps to illuminate the ways music represents the self throughout the genre of musical portraiture.


PMLA ◽  
1932 ◽  
Vol 47 (1) ◽  
pp. 89-96
Author(s):  
Daniel C. Boughner

From Plato and Aristotle, Hippocrates and Galen, through the medieval commentators, the Elizabethans inherited a body of complex psychological principles. An examination of these principles and their bearing on The Faerie Queene has so far been only casual and incidental. Since in Book ii, Canto ix, the poet combines one of the most widely used of medieval motifs—the conception of the body as a world, city, or castle—with certain current doctrines of psychology, such an inquiry is especially apposite. Spenser's use of the abundant contemporaneous literature of psychology affords material for an extended treatment such as that which Miss Anderson has made of Shakespeare's plays. The present study purposes to set forth one aspect of his system of psychology—his psychology of memory in the allegory of the Castle of Alma, to make clear the relationship of his system to the current Elizabethan doctrines, and to establish the purpose of certain departures from those doctrines.


2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Sonia Ciccazzo ◽  
Alfonso Esposito ◽  
Eleonora Rolli ◽  
Stefan Zerbe ◽  
Daniele Daffonchio ◽  
...  

The rhizosphere effect on bacterial communities associated with three floristic communities (RW, FI, and M sites) which differed for the developmental stages was studied in a high-altitude alpine ecosystem. RW site was an early developmental stage, FI was an intermediate stage, M was a later more matured stage. The N and C contents in the soils confirmed a different developmental stage with a kind of gradient from the unvegetated bare soil (BS) site through RW, FI up to M site. The floristic communities were composed of 21 pioneer plants belonging to 14 species. Automated ribosomal intergenic spacer analysis showed different bacterial genetic structures per each floristic consortium which differed also from the BS site. When plants of the same species occurred within the same site, almost all their bacterial communities clustered together exhibiting a plant species effect. Unifrac significance value (P<0.05) on 16S rRNA gene diversity revealed significant differences (P<0.05) between BS site and the vegetated sites with a weak similarity to the RW site. The intermediate plant colonization stage FI did not differ significantly from the RW and the M vegetated sites. These results pointed out the effect of different floristic communities rhizospheres on their soil bacterial communities.


Author(s):  
Nancy J. Stone

To evaluate students’ online learning environments, the relationship between personality and online learning success, and students’ perceptions about online proctoring during mandatory remote delivery due to the pandemic, students responded to an online survey. Learning environments generally included houses and rarely included on-campus housing. The specific room type was predominantly the bedroom. Only conscientiousness was related positively to anticipated semester GPA. The positive relationship between anticipated and overall GPA supports the notion that more conscientious students tend to be successful in online learning situations, as online education was rated as slightly ineffective. A majority of students did not see a need for online proctoring due to the inability or time required to search for materials, which would only harm one’s performance. There is a need to research further the impact of the study environment, relationship of the students’ personality to learning success, and consequences of online proctoring during remote learning.


Author(s):  
Martin Eisner

This article investigates the significance of the manuscripts of Virgil and other classical poets that Dante might have read. Calling attention to the presence of musical notation (neumes) in copies that share the particular Virgilian readings Dante quotes, this essay explores the resonance of one of those passages (Aeneas’ dream of Hector) in Dante’s poem. It shows how Dante uses this Virgilian episode to craft his encounter with Manfred where he considers the relationship of body and soul that constitutes one of the major differences between classical and Christian thought, as Augustine frequently noted. Just as Christian anthropology maintains that the body constitutes an essential element of the human person, this essay argues that the materiality of the texts Dante read constitutes a crucial source for understanding how Dante interpreted these texts.


1964 ◽  
Vol 6 (2) ◽  
pp. 169-178 ◽  
Author(s):  
R. V. Large

1. Thirty Suffolk × Half bred lambs were slaughtered at the following ages: two twin lambs at birth and two singles and two twins at 1, 2, 3, 4, 6, 8 and 16 weeks of age.2. The following weights were recorded: live-weight immediately before slaughter; and carcass, head, skin, feet, alimentary tract, heart, liver, kidneys, lungs and trachea, and blood immediately afterwards.3. The alimentary tract was emptied and weighed in four separate parts; reticulo-rumen, omasum-abomasum, small intestine, large intestine.4. The volumes of the reticulo-rumen and the omasum-abomasum were measured by immersing in water and filling the organs with water to 2 cm. pressure.5. The in vitro digestive efficiency of rumen liquor from lambs of 1, 2, 3 and 4 weeks of age was assessed.6. Empty body weight was considered to be valuable in comparing animals of different ages or from different feeding regimes or at different times of the year because variations in gut ‘fill’ were eliminated.7. There were no differences between singles and twins in the relationship of the fresh weights of the parts of the body to empty body weight, except that development of the liver and the blood was rather slower for singles.8. Little evidence was found of a difference in rate of development of the alimentary tract between singles an d twins, although the log an d square root transformation suggested a possible difference in reticulo-rumen size in favour of twins, significant at the 5% level.


2006 ◽  
Vol 66 (1a) ◽  
pp. 85-93 ◽  
Author(s):  
M. I. Hamann

From December 1995 to November 2000, the seasonal maturation of Glypthelmins vitellinophilum Dobbin, 1958, in its definitive host, the frog Lysapsus limellus Cope, 1862, was studied in a subtropical permanent pond in northeastern Argentina. The objectives of this study were: 1) to determine the infrapopulation dynamics of the parasite, analyzing the seasonal maturation cycle throughout the years; and 2) to examine the relationship between the intensity of trematode infection in different developmental stages (recruitment, growth and maturation) and the host's body length. Of a total of 1,400 frogs examined over 60 months (5 years), 38% were found to be infected with G. vitellinophilum, and the intensity of infection was 1-15 trematodes per frog. Specimens of G. vitellinophilum were present in L. limellus throughout the years, but did not show a pronounced seasonal maturation cycle. Possible reasons for these findings are discussed with reference to climatic fluctuations and biotic factors. The infective period of the parasite (stage I) occurred in summer, autumn and spring, coinciding with the time each frog cohort appeared. These infections were found principally in small body sizes (classes 1 and 2) of L. limellus. Juvenile and nongravid specimens of worms (stage II and III) were found in frogs of different body sizes throughout the period of investigation. Gravid specimens of the parasite (stage IV) were generally recorded in autumn, winter and spring, mainly in the bodies of larger frogs. The body length of Trematodes in stages I and IV was significantly and positively correlated with that of the frogs.


Sign in / Sign up

Export Citation Format

Share Document