scholarly journals Is oxygen limitation in warming waters a valid mechanism to explain decreased body sizes in aquatic ectotherms?

2018 ◽  
Vol 28 (2) ◽  
pp. 64-77 ◽  
Author(s):  
Asta Audzijonyte ◽  
Diego R. Barneche ◽  
Alan R. Baudron ◽  
Jonathan Belmaker ◽  
Timothy D. Clark ◽  
...  
Keyword(s):  
Oxygen Limitation ◽  
Body Sizes

scholarly journals Will giant polar amphipods be first to fare badly in an oxygen-poor ocean? Testing hypotheses linking oxygen to body size

2019 ◽  
Vol 374 (1778) ◽  
pp. 20190034 ◽  
Author(s):  
John I. Spicer ◽  
Simon A. Morley
Keyword(s):  
Climate Change ◽  
Body Size ◽  
Marine Invertebrates ◽  
Global Climate ◽  
Small Body ◽  
Oxygen Limitation ◽  
Amphipod Species ◽  
Evolutionary Innovation ◽  
Wide Range ◽  
Body Sizes

It has been suggested that giant Antarctic marine invertebrates will be particularly vulnerable to declining O 2 levels as our ocean warms in line with current climate change predictions. Our study provides some support for this oxygen limitation hypothesis, with larger body sizes being generally more sensitive to O 2 reductions than smaller body sizes. However, it also suggests that the overall picture is a little more complex. We tested predictions from three different, but overlapping, O 2 -related hypotheses accounting for gigantism, using four Antarctic amphipod species encompassing a wide range of body sizes. We found a significant effect of body size, but also of species, in their respiratory responses to acutely declining O 2 tensions. The more active lifestyle of intermediate-sized Prostebbingia brevicornis was supported by a better respiratory performance than predicted by the oxygen limitation hypothesis alone, but consistent with the symmorphosis hypothesis. We suggest that giant polar amphipods are likely to be some of the first to fare badly in an O 2 -poor ocean. However, the products of past evolutionary innovation, such as respiratory pigments that enhance O 2 -transport and novel gas exchange structures, may in some species offset any respiratory disadvantages of either large or small body size. This article is part of the theme issue ‘Physiological diversity, biodiversity patterns and global climate change: testing key hypotheses involving temperature and oxygen’.

The Age of Em

2016 ◽  
Author(s):  
Robin Hanson
Keyword(s):  
Career Paths ◽  
World Economy ◽  
Energy Use ◽  
New Technology ◽  
Wealth Inequality ◽  
Moral Progress ◽  
Fast Computer ◽  
The World ◽  
Body Sizes ◽  
Detailed Picture

Robots may one day rule the world, but what is a robot-ruled Earth like? Many think the first truly smart robots will be brain emulations or ems. Scan a human brain, then run a model with the same connections on a fast computer, and you have a robot brain, but recognizably human. Train an em to do some job and copy it a million times: an army of workers is at your disposal. When they can be made cheaply, within perhaps a century, ems will displace humans in most jobs. In this new economic era, the world economy may double in size every few weeks. Some say we can't know the future, especially following such a disruptive new technology, but Professor Robin Hanson sets out to prove them wrong. Applying decades of expertise in physics, computer science, and economics, he uses standard theories to paint a detailed picture of a world dominated by ems. While human lives don't change greatly in the em era, em lives are as different from ours as our lives are from those of our farmer and forager ancestors. Ems make us question common assumptions of moral progress, because they reject many of the values we hold dear. Read about em mind speeds, body sizes, job training and career paths, energy use and cooling infrastructure, virtual reality, aging and retirement, death and immortality, security, wealth inequality, religion, teleportation, identity, cities, politics, law, war, status, friendship and love. This book shows you just how strange your descendants may be, though ems are no stranger than we would appear to our ancestors. To most ems, it seems good to be an em.

scholarly journals A Farewell to the Encephalization Quotient: A New Brain Size Measure for Comparative Primate Cognition

2021 ◽  
pp. 1-12
Author(s):  
Carel P. van Schaik ◽  
Zegni Triki ◽  
Redouan Bshary ◽  
Sandra A. Heldstab
Keyword(s):  
Body Size ◽  
Cognitive Abilities ◽  
Brain Size ◽  
Estimation Error ◽  
Primate Species ◽  
Mammal Species ◽  
Mean Values ◽  
Encephalization Quotient ◽  
Body Sizes ◽  
Size Measure

Both absolute and relative brain sizes vary greatly among and within the major vertebrate lineages. Scientists have long debated how larger brains in primates and hominins translate into greater cognitive performance, and in particular how to control for the relationship between the noncognitive functions of the brain and body size. One solution to this problem is to establish the slope of cognitive equivalence, i.e., the line connecting organisms with an identical bauplan but different body sizes. The original approach to estimate this slope through intraspecific regressions was abandoned after it became clear that it generated slopes that were too low by an unknown margin due to estimation error. Here, we revisit this method. We control for the error problem by focusing on highly dimorphic primate species with large sample sizes and fitting a line through the mean values for adult females and males. We obtain the best estimate for the slope of circa 0.27, a value much lower than those constructed using all mammal species and close to the value expected based on the genetic correlation between brain size and body size. We also find that the estimate of cognitive brain size based on cognitive equivalence fits empirical cognitive studies better than the encephalization quotient, which should therefore be avoided in future studies on primates and presumably mammals and birds in general. The use of residuals from the line of cognitive equivalence may change conclusions concerning the cognitive abilities of extant and extinct primate species, including hominins.

Translation and Validation of the Brazilian Portuguese Version of the Broad Conceptualization of Beauty Scale With Brazilian Women

2021 ◽  
pp. 036168432110134
Author(s):  
Alessandra Costa Pereira Junqueira ◽  
Tracy L. Tylka ◽  
Sebastião de Sousa Almeida ◽  
Telma Maria Braga Costa ◽  
Maria Fernanda Laus
Keyword(s):  
Factor Structure ◽  
Reliability And Validity ◽  
Well Being ◽  
The United States ◽  
Brazilian Portuguese ◽  
Incremental Validity ◽  
Body Appreciation ◽  
Two Factors ◽  
Body Sizes ◽  
Definition Of

In many countries, women are socialized to adopt a narrow definition of beauty. Research has revealed that, in the United States and China, the ability to broadly conceptualize beauty (perceive beauty in diverse body sizes, shapes, and appearances) is linked to women’s lower anti-fat attitudes, higher body appreciation, and higher well-being. In this study, we translated an existing measure of this construct, the Broad Conceptualization of Beauty Scale (BCBS), into Brazilian Portuguese and evaluated the factor structure and reliability and validity of its scores with a diverse sample of 563 Portuguese women. Findings revealed that the Brazilian Portuguese BCBS contains two factors—external/appearance features of beauty (BCBS-E) and internal features of beauty (BCBS-I)—contrary to the unidimensional factor structure found in previous studies. Support for internal consistency and 3-week test–retest reliability was garnered. Total BCBS and BCBS-E scores evidenced convergent, discriminant, and incremental validity, whereas the BCBS-I did not accrue substantial convergent or incremental validity support beyond its inverse bivariate association with anti-fat attitudes. We recommend the use of the Brazilian Portuguese BCBS in body image research programs as well as clinical practice and prevention programs with Brazilian women seeking support for body dissatisfaction and disordered eating.

scholarly journals The food web in a subterranean ecosystem is driven by intraguild predation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Andrea Parimuchová ◽  
Lenka Petráková Dušátková ◽  
Ľubomír Kováč ◽  
Táňa Macháčková ◽  
Ondřej Slabý ◽  
...  
Keyword(s):  
Food Web ◽  
Trophic Interactions ◽  
Intraguild Predation ◽  
Linear Models ◽  
Niche Overlap ◽  
Trophic Niche ◽  
High Availability ◽  
Large Prey ◽  
Arthropod Predators ◽  
Body Sizes

AbstractTrophic interactions of cave arthropods have been understudied. We used molecular methods (NGS) to decipher the food web in the subterranean ecosystem of the Ardovská Cave (Western Carpathians, Slovakia). We collected five arthropod predators of the species Parasitus loricatus (gamasid mites), Eukoenenia spelaea (palpigrades), Quedius mesomelinus (beetles), and Porrhomma profundum and Centromerus cavernarum (both spiders) and prey belonging to several orders. Various arthropod orders were exploited as prey, and trophic interactions differed among the predators. Linear models were used to compare absolute and relative prey body sizes among the predators. Quedius exploited relatively small prey, while Eukoenenia and Parasitus fed on relatively large prey. Exploitation of eggs or cadavers is discussed. In contrast to previous studies, Eukoenenia was found to be carnivorous. A high proportion of intraguild predation was found in all predators. Intraspecific consumption (most likely cannibalism) was detected only in mites and beetles. Using Pianka’s index, the highest trophic niche overlaps were found between Porrhomma and Parasitus and between Centromerus and Eukoenenia, while the lowest niche overlap was found between Parasitus and Quedius. Contrary to what we expected, the high availability of Diptera and Isopoda as a potential prey in the studied system was not corroborated. Our work demonstrates that intraguild diet plays an important role in predators occupying subterranean ecosystems.

scholarly journals Impact of “non-lethal” tarsal clipping on bumble bees (Bombus vosnesenskii) may depend on queen stage and worker size

2021 ◽  
Author(s):  
John M. Mola ◽  
Clara Stuligross ◽  
Maureen L. Page ◽  
Danielle Rutkowski ◽  
Neal M. Williams
Keyword(s):  
Genetic Material ◽  
Population Monitoring ◽  
First Year ◽  
Negative Effects ◽  
Worker Size ◽  
Monitoring Tools ◽  
Individual Survival ◽  
Body Sizes ◽  
Negative Effect ◽  
Worker Caste

Abstract Recent bumble bee declines have prompted the development of novel population monitoring tools, including the use of putatively non-lethal tarsal clipping to obtain genetic material. However, the potential side effects of tarsal clipping have only been tested in the worker caste of a single domesticated species, prompting the need to more broadly test whether tarsal clipping negatively affects sampled individuals. To determine if tarsal clipping reduces queen survivorship and colony establishment, we collected wild queens of Bombus vosnesenskii and clipped tarsi from a single leg of half the individuals. We reared captive queens and estimated survivorship and nest establishment success. We also clipped tarsi of workers from a subset of colonies across a range of body sizes. We found no consistent negative effect of clipping on queen survival. In the first year, clipped nest-searching queens suffered heavy mortality, but there was no effect on foraging queens. The following year, we found no effect of clipping on queen survival or establishment. Clipping did not reduce overall worker survival but reduced survivorship for those in the smallest size quartile. Implications for insect conservation Our findings suggest tarsal clipping does not have consistent negative effects on individual survival. However, our results varied with queen behavioral state, year, and worker size, suggesting differences within and among species and interactions with landscape stressors warrant further study. In the interim, we recommend researchers and conservationists minimize the use of tarsal clipping for sensitive species, populations, or small workers except in cases of exceptional scientific need.

Assessing the Ergonomic Benefits of a New Adjustable Forklift Backrest

2020 ◽  
Vol 64 (1) ◽  
pp. 976-980
Author(s):  
Pranav Madhav Kuber ◽  
Ehsan Rashedi
Keyword(s):  
Comparative Study ◽  
Motion Capture ◽  
Center Of Pressure ◽  
Body Movement ◽  
Pressure Change ◽  
Motion Capture System ◽  
Design Features ◽  
Wide Range ◽  
Body Sizes ◽  
The Mean

A new forklift backrest has been developed by incorporating adjustability concepts into the design to facilitate comfort to a wide range of users. We have conducted a comparative study between the new and original backrests to assess the effectiveness of design features. Using the phenomenon of restlessness, discomfort of the user was associated with the amount of body movement, where we have used a motion- capture system and a force platform to quantify the individuals’ movement for a wide range of body sizes. Meanwhile, subjective comfort and design feedback were collected using a questionnaire. Our results showed a reduction in the mean torso movement and the maximum center of pressure change of location by 300 and 6 mm, respectively, for the new design. Taking advantage of adjustability feature, the new backrest design exhibited enhanced comfort for longer durations and reduced magnitude of discomfort for a wide range of participants’ body sizes.

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