scholarly journals The role of body temperature in regulating brain and body sizes in hominin evolution

2020 ◽  
Author(s):  
Manasvi Lingam

AbstractA number of models have posited that the concomitant evolution of large brains and increased body sizes in hominins was constrained by metabolic costs. In such studies, the impact of body temperature has not been sufficiently addressed despite the well-established fact that the rates of most physiological processes are manifestly temperature-dependent. Hence, the role of body temperature in modulating the number of neurons and body size is investigated in this work by means of a simple quantitative model. It is determined that modest deviations in the body temperature (i.e., by a few degrees Celsius) might bring about substantive changes in brain and body parameters. In particular, a higher body temperature might prove amenable to an increase in the number of neurons, a higher brain-to-body mass ratio and fewer hours expended on feeding activities, while the converse applies when the temperature is lowered. It is therefore argued that future studies must endeavour to explore and incorporate the effects of body temperature in metabolic theories of hominin evolution, while also accounting for other factors such as foraging efficiency, diet and fire control in tandem.

2021 ◽  
Vol 22 (11) ◽  
pp. 5843
Author(s):  
Chloé Turpin ◽  
Aurélie Catan ◽  
Olivier Meilhac ◽  
Emmanuel Bourdon ◽  
François Canonne-Hergaux ◽  
...  

The development and progression of atherosclerosis (ATH) involves lipid accumulation, oxidative stress and both vascular and blood cell dysfunction. Erythrocytes, the main circulating cells in the body, exert determinant roles in the gas transport between tissues. Erythrocytes have long been considered as simple bystanders in cardiovascular diseases, including ATH. This review highlights recent knowledge concerning the role of erythrocytes being more than just passive gas carriers, as potent contributors to atherosclerotic plaque progression. Erythrocyte physiology and ATH pathology is first described. Then, a specific chapter delineates the numerous links between erythrocytes and atherogenesis. In particular, we discuss the impact of extravasated erythrocytes in plaque iron homeostasis with potential pathological consequences. Hyperglycaemia is recognised as a significant aggravating contributor to the development of ATH. Then, a special focus is made on glycoxidative modifications of erythrocytes and their role in ATH. This chapter includes recent data proposing glycoxidised erythrocytes as putative contributors to enhanced atherothrombosis in diabetic patients.


Water exchange between insects and their environment via the vapour phase includes influx and efflux components. The pressure cycle theory postulates that insects (and some other arthropods) can regulate the relative rates of influx and efflux of water vapour by modulating hydrostatic pressures at a vapour-liquid interface by compressing or expanding a sealed, gas-filled cavity. Some such cavities, like the tracheal system, could be compressed by elevated pressure in all or part of the haemocoele. Others, perhaps including the muscular rectum of flea prepupae, could be compressed by intrinsic muscles. Maddrell Insect Physiol . 8, 199 (1971)) suggested a pressure cycle mechanism of this kind to account for rectal uptake of water vapour in Thermobia but did not find it compatible with quantitative information then available. Newer evidence conforms better with the proposed mechanism. Cyclical pressure changes are of widespread occurrence in insects and have sometimes been shown to depend on water status. Evidence is reviewed for the role of the tracheal system as an avenue for net exchange of water between the insect and its environment. Because water and respiratory gases share common pathways, most published findings fail to distinguish between the conventional view that the tracheal system has evolved as a site for distribution and exchange of respiratory gases and that any water exchange occurring in it is generally incidental and nonadaptive, and the theory proposed here. The pressure cycle theory offers a supplementary explanation not incompatible with evidence so far available. The relative importance of water economy and respiratory exchange in the functioning of compressible cavities such as the tracheal system remains to be explored. Some further implications of the pressure cycle theory are discussed. Consideration is given to the possible involvement of vapour-phase transport in the internal redistribution of water within the body. It is suggested that some insect wings may constitute internal vapour-liquid exchange sites, where water can move from the body fluids to the intratracheal gas. Ambient and body temperature must influence rates of vapour-liquid mass transfer. If elevated body temperature promotes evaporative discharge of the metabolic water burden that has been shown to accumulate during flight in some large insects, their minimum threshold thoracic temperature for sustained flight may relate to the maintenance of water balance. The role of water economy in the early evolution of insect wings is considered. Pressure cycles might help to maintain water balance in surface-breathing insects living in fresh and saline waters, but the turbulence of the surface of the open sea might prevent truly marine forms from using this mechanism.


2018 ◽  
Vol 55 (4) ◽  
pp. 383-398
Author(s):  
David S Scott

Although sport is widely utilised as a tool for personal development, capacity building, and fostering peace, there are still numerous theoretical gaps in our knowledge about how sport influences individuals’ identities, and how this translates into their everyday lives. Within the academic literature there has been seemingly little focus placed upon participants’ emotional and embodied accounts of their sport-for-development (SfD) experiences. This paper uses phenomenologically-inspired theory to explore individuals’ lived experiences of a SfD course, and their descriptions of the social interactions and feelings of confidence they encountered, in order to address this lack of experiential data. An ethnographic methodology was used to collect data through four sports leadership course observations, and cyclical interviews over 4–10 months with eleven course attendees, plus individual interviews with five tutors. Participants’ understandings of their course experiences and the subsequent influence these understandings had on their lives were described through their use of the term confidence. A further phenomenological and sociological interrogation of this term enabled confidence to be seen as being experienced as a ‘frame’ and ‘through the body’ by participants. This study provides original conceptualisations of confidence in relation to participants’ SfD experiences, as well as important discussions regarding the role of emotions and embodiment in understanding the impact of SfD on participants’ everyday lives.


2001 ◽  
Vol 7 (5) ◽  
pp. 343-349 ◽  
Author(s):  
Dinesh Bhugra ◽  
Oyedeji Ayonrinde

The association of life events with the onset of various psychiatric disorders is well-known. The body of evidence has highlighted the impact of negative or positive life events on the genesis of common mental disorders, especially depression. These findings have been replicated across different cultures, although the impact of different life events varies between cultures. In addition, the roles of chronic difficulties (defined in Life events and psychiatric disorders, below) and resulting ongoing chronic stress have been shown to contribute to vulnerability to certain mental illnesses. However, data on the impact of life events, especially those perceived as racial, on members of minority ethnic groups are rather sparse. The questions that need to be addressed concern the perception of life events as racial, the role of pervasive and perceived institutional and individual racism, and chronic difficulties.


2020 ◽  
Vol 12 (11) ◽  
pp. 4635 ◽  
Author(s):  
Małgorzata Dzimińska ◽  
Justyna Fijałkowska ◽  
Łukasz Sułkowski

This paper aims to propose a conceptual model that synthesizes the existing findings concerning universities as culture change agents for sustainable development. The model could serve as a guidance on how universities might get involved in the pro-SD activities. It also underlines the prerequisite of the quality culture that should be introduced within all the activities of universities to successfully act as culture change agents for SD. This paper builds upon the holistic and inter-disciplinary approach to demonstrate that SD does not happen in isolation and that the role of universities in its creation is significant. This study includes a literature review to contextualize the impact of universities on culture and their potential role in SD. The conclusions stemming from the literature review materialize in the proposal of the conceptual model of the university as the culture change agent for SD. The elaborated framework responds to the need for greater clarity, ordering and systematization of the role of universities in the processes of initiating, promoting and modelling the SD-oriented changes while appreciating the role of culture as an enabler, means of social change and a result of SD-focused interventions. The paper contributes to the body of knowledge by offering a novel perspective on the assumed interrelations between university, its quality culture, university main operations such as education, research and engagement with the society as well as the culture and the agency of stakeholders in the context of meeting the world’s current demands without compromising the needs of future generations.


2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 192-193
Author(s):  
Sheyenne M Augenstein ◽  
Meredith A Harrison ◽  
Sarah C Klopatek ◽  
James W Oltjen

Abstract Heat stress continues to be a challenge for feedlot producers, forcing physiological adaptations in beef cattle that can have a negative impact on gain and carcass quality. Feedlots may want to incorporate systems that aid in mitigating heat stress, including sprinkler systems, which are commonly found on dairies. The objective of this study was to determine the impact of sprinkler systems on the body temperature of growing feedlot steers applied at three different temperature thresholds. Thirty-two Angus-cross beef steers (298 ± 15 SD days of age) were randomly assigned to 8 pens. Treatments were assigned to pens according to location to avoid drainage issues, with one replicate located on the eastern side of the feedlot and the other replicate located on the western side. Treatments including no sprinklers (C), high temperature threshold sprinklers (HT), moderate temperature threshold sprinklers (MT) or low temperature threshold sprinklers (LT). Sprinklers (flow rate: 5.11 L/min) were activated at 33°C (HT), 28°C (MT), and 23°C (LT) for five minutes at corresponding temperatures every thirty minutes for 57 days. Rectal temperature of steers in their pens was measured in the morning (0800 h), afternoon (1500 h), and evening (1900 h) three days each week (Monday, Wednesday, Friday) for a total of 19 experimental days. Weather measurements, including ambient temperature, windspeed, humidity and solar radiation were recorded at each measurement time along with the maximum values for each day. The change in body temperature (ΔBT) between the morning and afternoon was affected by ambient temperature (P < 0.01); MT (P = 0.02) and LT (P = 0.02) – different than C. There was no significant difference between sprinkler treatments and the control group (P > 0.05). Day affected (ΔBT) between the morning and afternoon (P < 0.05) and the afternoon and evening (P < 0.05). When averaged by day, the control group was significantly higher than MT (P = 0.04) between the morning and afternoon. The control group was also significantly higher than LT between the morning and afternoon (P = 0.03) and the afternoon and evening (P < 0.01). The change in steer body temperature between afternoon and morning was affected by ambient temperature, and averaged across days, lowering the temperature threshold for sprinkling decreased in the afternoon and evening body temperature increase in steers.


Nanomedicine ◽  
2020 ◽  
Vol 15 (10) ◽  
pp. 1037-1061
Author(s):  
Muhammad Ovais ◽  
Susheel Kumar Nethi ◽  
Saleem Ullah ◽  
Irshad Ahmad ◽  
Sudip Mukherjee ◽  
...  

In spite of radical advances in nanobiotechnology, the clinical translation of nanoparticle (NP)-based agents is still a major challenge due to various physiological factors that influence their interactions with biological systems. Recent decade witnessed meticulous investigation on protein corona (PC) that is the first surrounds NPs once administered into the body. Formation of PC around NP surface exhibits resilient effects on their circulation, distribution, therapeutic activity, toxicity and other factors. Although enormous literature is available on the role of PC in altering pharmacokinetics and pharmacodynamics of NPs, understanding on its analytical characterization methods still remains shallow. Therefore, the current review summarizes the impact of PC on biological fate of NPs and stressing on analytical methods employed for studying the NP-PC.


2020 ◽  
Author(s):  
Melanie Tietje ◽  
William J. Foster ◽  
Jana Gliwa ◽  
Clara Lembke ◽  
Autumn Pugh ◽  
...  

<p> The impact of mass extinctions on the body sizes of animals has received considerable attention and debate, as to whether the reduced size of post-extinction organisms is due to the selective extinction of large species, absence of large species as a stochastic effect of low-diversity faunas, or a size decrease within surviving genera and species. Here, we investigated the body sizes of bivalves following the end-Permian mass extinction event and show that the shell size increase of bivalve genera was driven by both evolutionary and ecophenotypic responses. First, some genera show significant increases in body size with the evolution of new species. Further, the same genera record significant within-species increases in average and maximum body size into the late Induan, indicating that ecophenotypic changes were also involved on long-term body size trends. These increases are associated with invigorated ocean circulation, improved oxygenation of the seafloor, and probably increased food supply.</p>


2017 ◽  
Author(s):  
Simon V. Reichel ◽  
Susanna Labisch ◽  
Jan-Henning Dirks

AbstractMany insects are able to precisely control their jumping movements. Previous studies have shown that many falling insects have some degree of control of their landing-orientation, indicating a possible significant biomechanical role of the exoskeleton in air righting mechanisms. Once in the air, the properties of the actual landing site are almost impossible to predict. Falling insects thus have to cope mostly with the situation at impact. What exactly happens at the impact? Do locusts actively ‘prepare for landing’ while falling, or do they just ‘crash’ into the substrate?Detailed impact analyses of free falling Schistocerca gregaria locusts show that most insects typically crashed onto the substrate. There was no notable impact-reducing behaviour (protrusion of legs, etc.). Independent of dropping angle, both warm and cooled locusts mostly fell onto head and thorax first. Our results also show that alive warm locusts fell significantly faster than inactive or dead locusts. This indicates a possible tradeoff between active control vs. reduced speed. Looking at the morphology of the head-thorax connection in locusts, we propose that the anterior margin of the pronotum might function as a ‘toby collar’ structure, reducing the risk of impact damage to the neck joint. Interestingly, at impact alive insects also tended to perform a bending movement of the body.This biomechanical adaptation might reduce the rebound and shorten the time to recover. The adhesive pads also play an important role to reduce the time to recover by anchoring the insect to the substrate.


2021 ◽  
Author(s):  
Zhou-Tong Dai ◽  
Yuan Xiang ◽  
Xing-Hua Liao

Abstract Background Uterine Corpus Endometrial Cancer (UCEC) is one of the three common malignant tumors of the female reproductive tract. According to reports, the cure rate of early UCEC can reach 95%. Therefore, the development of prognostic markers will help UCEC patients to find the disease earlier and develop treatment earlier. The ALDH family was first discovered to be the essential gene of the ethanol metabolism pathway in the body. Recent studies have shown that ALDH can participate in the regulation of cancer. Methods We used the gene profile data of 33 cancers in the TCGA database to analyze the expression and survival of the ALDH family. GO, KEGG, PPI multiple functional analysis was used to predict the regulatory role of ALDH family in cancer. In addition, using CCK-8, colony formation, nude mouse tumor formation and other methods, the in vitro function of UCEC cancer cell lines was tested to further confirm the key role of ALDH2 expression in the proliferation of UCEC cell lines. Finally, Lasso and Cox regression methods were used to establish an overall survival prognosis model based on ALDH2 expression. Result In our research, we explored the expression of ALDH family in 33 cancers. It was found that ALDH2 was abnormally expressed in UCEC. Besides, in vivo and in vitro experiments were conducted to explore the effect of ALDH2 expression on the proliferation of UCEC cell lines. Meanwhile, the change of its expression is not due to gene mutations, but is regulated by miR-135-3p. At the same time, the impact of ALDH2 changes on the survival of UCEC patients is deeply discussed. Finally, a nomogram for predicting survival was constructed, with a C-index of 0.798 and AUC of 0.764. Conclusion This study suggests that ALDH2 may play a crucial role in UCEC progression and has the potential as a prognostic biomarker of UCEC.


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