scholarly journals Does Hyperoxia Restrict Pyrenean Rock Lizards Iberolacerta bonnali to High Elevations?

Diversity ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 200
Author(s):  
Eric J. Gangloff ◽  
Sierra Spears ◽  
Laura Kouyoumdjian ◽  
Ciara Pettit ◽  
Fabien Aubret
Keyword(s):  
High Elevation ◽  
Conservation Strategy ◽  
The Novel ◽  
Thermal Physiology ◽  
Treatment Groups ◽  
Thermal Performance Curve ◽  
And Performance ◽  
Thermal Preferences ◽  
High Elevations ◽  
Intense Radiation

Ectothermic animals living at high elevation often face interacting challenges, including temperature extremes, intense radiation, and hypoxia. While high-elevation specialists have developed strategies to withstand these constraints, the factors preventing downslope migration are not always well understood. As mean temperatures continue to rise and climate patterns become more extreme, such translocation may be a viable conservation strategy for some populations or species, yet the effects of novel conditions, such as relative hyperoxia, have not been well characterised. Our study examines the effect of downslope translocation on ectothermic thermal physiology and performance in Pyrenean rock lizards (Iberolacerta bonnali) from high elevation (2254 m above sea level). Specifically, we tested whether models of organismal performance developed from low-elevation species facing oxygen restriction (e.g., hierarchical mechanisms of thermal limitation hypothesis) can be applied to the opposite scenario, when high-elevation organisms face hyperoxia. Lizards were split into two treatment groups: one group was maintained at a high elevation (2877 m ASL) and the other group was transplanted to low elevation (432 m ASL). In support of hyperoxia representing a constraint, we found that lizards transplanted to the novel oxygen environment of low elevation exhibited decreased thermal preferences and that the thermal performance curve for sprint speed shifted, resulting in lower performance at high body temperatures. While the effects of hypoxia on thermal physiology are well-explored, few studies have examined the effects of hyperoxia in an ecological context. Our study suggests that high-elevation specialists may be hindered in such novel oxygen environments and thus constrained in their capacity for downslope migration.

scholarly journals High temperatures limit developmental resilience to high-elevation hypoxia in the snake Natrix maura (Squamata: Colubridae)

2020 ◽  
Vol 132 (1) ◽  
pp. 116-133
Author(s):  
Jérémie Souchet ◽  
Coralie Bossu ◽  
Elodie Darnet ◽  
Hugo Le Chevalier ◽  
Manon Poignet ◽  
...  
Keyword(s):  
High Temperatures ◽  
Performance Metrics ◽  
Incubation Temperature ◽  
Early Life History ◽  
High Elevation ◽  
Performance Constraints ◽  
Lower Oxygen ◽  
And Performance ◽  
High Elevations ◽  
Natrix Maura

Abstract Climate change is generating range shifts in many organisms, notably along the altitudinal gradient. However, moving up in altitude exposes organisms to lower oxygen availability, which may negatively affect development and fitness, especially at high temperatures. To test this possibility in a potentially upward-colonizing species, we artificially incubated developing embryos of the viperine snake Natrix maura Linnaeus 1758, using a split-clutch design, in conditions of extreme high elevation or low elevation at two ecologically-relevant incubation temperatures (24 and 32 °C). Embryos at low and extreme high elevations incubated at cool temperatures did not differ in development time, hatchling phenotype or locomotor performance. However, at the warmer incubation temperature and at extreme high elevation, hatching success was reduced. Further, embryonic heart rates were lower, incubation duration longer and juveniles born smaller. Nonetheless, snakes in this treatment were faster swimmers than siblings in other treatment groups, suggesting a developmental trade-off between size and performance. Constraints on development may be offset by the maintenance of important performance metrics, thus suggesting that early life-history stages will not prevent the successful colonization of high-elevation habitat even under the dual limitations of reduced oxygen and increased temperature.

scholarly journals Soft Spherical Tensegrity Robot Design Using Rod-Centered Actuation and Control

2016 ◽  
Author(s):  
Lee-Huang Chen ◽  
Kyunam Kim ◽  
Ellande Tang ◽  
Kevin Li ◽  
Richard House ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Low Cost ◽  
Space Exploration ◽  
Robot Design ◽  
The Novel ◽  
Flexible Design ◽  
Spherical Robot ◽  
Potential Benefits ◽  
And Performance ◽  
And Control

This paper presents the design, analysis and testing of a fully actuated modular spherical tensegrity robot for co-robotic and space exploration applications. Robots built from tensegrity structures (composed of pure tensile and compression elements) have many potential benefits including high robustness through redundancy, many degrees of freedom in movement and flexible design. However to fully take advantage of these properties a significant fraction of the tensile elements should be active, leading to a potential increase in complexity, messy cable and power routing systems and increased design difficulty. Here we describe an elegant solution to a fully actuated tensegrity robot: The TT-3 (version 3) tensegrity robot, developed at UC Berkeley, in collaboration with NASA Ames, is a lightweight, low cost, modular, and rapidly prototyped spherical tensegrity robot. This robot is based on a ball-shaped six-bar tensegrity structure and features a unique modular rod-centered distributed actuation and control architecture. This paper presents the novel mechanism design, architecture and simulations of TT-3, the first untethered, fully actuated cable-driven six-bar tensegrity spherical robot ever built and tested for mobility. Furthermore, this paper discusses the controls and preliminary testing performed to observe the system’s behavior and performance.

scholarly journals Pathogenic Variability of Pyricularia grisea from the High- and Mid-Elevation Zones of Bhutan

2000 ◽  
Vol 90 (6) ◽  
pp. 621-628 ◽  
Author(s):  
Thinlay ◽  
R. S. Zeigler ◽  
M. R. Finckh
Keyword(s):  
Rice Cultivar ◽  
High Elevation ◽  
Individual Plant ◽  
Growing Seasons ◽  
Reaction Index ◽  
Agroecological Zones ◽  
Pathogenic Variability ◽  
Almost All ◽  
High Elevations ◽  
Virulence Spectrum

Thirty isolates of P. griseacollected from rice during a blast epidemic in 1995 in the high (1,800 to 2,600 m) and middle (1,200 to 1,800 m) elevations of Bhutan and 80 isolates collected from one rice cultivar from two high- and two mid-elevation sites in 1996 were analyzed for virulence. Differential varieties were indica CO39, with five near-isogenic lines (NILs) for resistance genes in the genetic background of CO39, and japonica Lijiangxintuanheigu (LTH), with five NILs for LTH. Twelve selected Bhutanese landraces also were studied. In addition, 10 blast nurseries consisting of the NIL sets, important local landraces, and representatives of international differential groups were established in the 1996 and 1997 growing seasons in the mid- and high-elevation agroecological zones. The 110 isolates were differentiated into 53 pathotypes based on the 2 NIL sets. Thirteen isolates were avirulent on all of the NILs but were compatible with some landraces. Several isolates were able to attack one of the NILs of CO39 but not CO39. These results strongly suggest that both CO39 and LTH possess previously unidentified resistance. The landraces were not uniform in their reactions to the isolates. When a reaction index taking into account all individual plant reactions was used, isolates that had been assigned to the same pathotype could be further differentiated, indicating that the NIL sets could not completely discriminate virulences in Bhutanese P. grisea populations. In the trap nurseries, disease was always present in the middle elevations, but disease was very low during July 1996 in the high elevations and only present during August and September 1997. Almost all varietal groups were more frequently attacked in the middle than in the high elevations, indicating that the virulence spectrum is wider and the conduciveness of the environment is greater in the middle elevations. Landraces from the high elevations were most susceptible, followed by international differential groups 7 and 8. The results suggest that selection has yielded landraces with more complete and complex resistance in the more disease-conducive mid-elevation environment. At the same time, the pathogen population also possesses a wider virulence spectrum in that environment.

scholarly journals In Vitro Activity of the Novel Pleuromutilin Lefamulin (BC-3781) and Effect of Efflux Pump Inactivation on Multidrug-Resistant and Extensively Drug-Resistant Neisseria gonorrhoeae

2017 ◽  
Vol 61 (11) ◽  
Author(s):  
Susanne Jacobsson ◽  
Susanne Paukner ◽  
Daniel Golparian ◽  
Jörgen S. Jensen ◽  
Magnus Unemo
Keyword(s):  
Efflux Pump ◽  
Multidrug Resistant ◽  
Cross Resistance ◽  
Drug Resistant ◽  
The Novel ◽  
Extensively Drug Resistant ◽  
Optimal Dosing ◽  
And Performance ◽  
Reference Strains

ABSTRACT We evaluated the activity of the novel semisynthetic pleuromutilin lefamulin, inhibiting protein synthesis and growth, and the effect of efflux pump inactivation on clinical gonococcal isolates and reference strains (n = 251), including numerous multidrug-resistant and extensively drug-resistant isolates. Lefamulin showed potent activity against all gonococcal isolates, and no significant cross-resistance to other antimicrobials was identified. Further studies of lefamulin are warranted, including in vitro selection and mechanisms of resistance, pharmacokinetics/pharmacodynamics, optimal dosing, and performance in randomized controlled trials.

Preparation and performance of the novel PVDF ultrafiltration membranes blending with PVA modified SiO2 hydrophilic nanoparticles

2018 ◽  
Vol 59 (S1) ◽  
pp. E412-E421 ◽  
Author(s):  
De Sun ◽  
Dongmin Yue ◽  
Bingbing Li ◽  
Zhaoshan Zheng ◽  
Xiangchun Meng
Keyword(s):  
The Novel ◽  
Ultrafiltration Membranes ◽  
And Performance

scholarly journals Effects of Spondias mombin l. On milk composition of lactating West African Dwarf (WAD) ewes

2020 ◽  
Vol 36 (2) ◽  
pp. 335-343
Author(s):  
M. A. Oguike ◽  
M. E. Udeh
Keyword(s):  
Milk Protein ◽  
Post Partum ◽  
Milk Composition ◽  
West African ◽  
Trial Group ◽  
Total Solids ◽  
Treatment Groups ◽  
West African Dwarf ◽  
Spondias Mombin ◽  
And Performance

A study was conducted to investigate the effects of Spondias mombin on milk composition using milk from twelve lactating West African dwarf (WAD) ewes. The lactating ewes were assigned to two treatment groups of six ewes per group, designated T1 and T2 representing control and trial group, respectively The ewes in T2, the trial group were fed Spondias mombin L. post partum while those in T1 the control were not fed Spondias mombin. Colostrum samples were collected from each ewe the first four days following parturition while normal milk was sampled for analysis after two weeks of lambing through 12 weeks of lactation. The constituents studied were lactose, milk protein, butterfat, ash, total solids and solid non-fat. Results showed that the colostrums of ewes fed S. mombin had significantly higher (P<0.05) total solids, and solids not fat contents of 18.34 and 11.31% respectively, than those of the control ewes which were 17.32 and 10.35%, respectively. The other constituents of colostrums of the different groups were not significantly different (P>0.05). At week 2 of lactation, lactose (3.98%) and ash (0.98%) concentrations of normal milk of treated ewes were significantly higher (P<0.05) than those of the control ewes for lactose (3.74%) and ash (0.65%). Also by the 12th week of lactation, ash contents of the two treatments were significantly different (P<0.05) with T2 having higher value. There were no significant differences (P>0.05) in the normal milk compositions of both groups in weeks 4, 6, 8 and 10. These results suggest that feeding S. mombin to lactating ewes could be useful in improving on the milk composition of WAD ewes and has no adverse effects on their general health and performance.

scholarly journals High turn-over rates at the upper range limit and elevational source-sink dynamics in a widespread songbird

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Martin U. Grüebler ◽  
Johann von Hirschheydt ◽  
Fränzi Korner-Nievergelt
Keyword(s):  
Environmental Gradients ◽  
Elevational Gradient ◽  
High Elevation ◽  
Range Limit ◽  
Apparent Survival ◽  
Breeding Sites ◽  
Mobile Species ◽  
Source Sink ◽  
Turn Over ◽  
High Elevations

AbstractThe formation of an upper distributional range limit for species breeding along mountain slopes is often based on environmental gradients resulting in changing demographic rates towards high elevations. However, we still lack an empirical understanding of how the interplay of demographic parameters forms the upper range limit in highly mobile species. Here, we study apparent survival and within-study area dispersal over a 700 m elevational gradient in barn swallows (Hirundo rustica) by using 15 years of capture-mark-recapture data. Annual apparent survival of adult breeding birds decreased while breeding dispersal probability of adult females, but not males increased towards the upper range limit. Individuals at high elevations dispersed to farms situated at elevations lower than would be expected by random dispersal. These results suggest higher turn-over rates of breeding individuals at high elevations, an elevational increase in immigration and thus, within-population source-sink dynamics between low and high elevations. The formation of the upper range limit therefore is based on preference for low-elevation breeding sites and immigration to high elevations. Thus, shifts of the upper range limit are not only affected by changes in the quality of high-elevation habitats but also by factors affecting the number of immigrants produced at low elevations.

scholarly journals Microgeographic variation in locomotor traits among lizards in a human-built environment

2016 ◽  
Author(s):  
Colin Donihue
Keyword(s):  
Built Environment ◽  
Habitat Structure ◽  
Vertical Structure ◽  
Maximum Velocity ◽  
The Novel ◽  
Novel Habitat ◽  
Microgeographic Variation ◽  
And Performance ◽  
Locomotor Capacity

Microgeographic variation in fitness-relevant traits may be more common than previously appreciated. The fitness of many vertebrates is directly related to their locomotor capacity, a whole-organism trait integrating behavior, morphology, and physiology. Because locomotion is inextricably related to context, I hypothesized that it might vary with habitat structure in a wide-ranging lizard, Podarcis erhardii, found in the Greek Cyclade Islands. I compared lizard populations living on human-built rock walls, a novel habitat with complex vertical structure, with nearby lizard populations that are naive to human-built infrastructure and live in flat, loose-substrate habitat. I tested for differences in morphology, behavior, and performance. Lizards from built sites were larger and had significantly (and relatively) longer forelimbs and hindlimbs. The differences in hindlimb morphology were especially pronounced for distal components – the foot and longest toe. These morphologies facilitated a significant behavioral shift in jumping propensity across a rocky experimental substrate. I found no difference in maximum velocity between these populations, however females originating from wall sites potentially accelerated faster over the rocky experimental substrate. The variation between these closely neighboring populations suggests that the lizards inhabiting walls have experienced a suite of trait changes enabling them to take advantage of the novel habitat structure created by humans.

scholarly journals Development and Characterization of a Novel Porous-Media Borosilicate Glass Ion Sources for Electrospray Thruster

Aerospace ◽  
2021 ◽  
Vol 8 (10) ◽  
pp. 297
Author(s):  
Yuntian Yang ◽  
Dawei Guo ◽  
Xiaokang Li ◽  
Leimin Deng ◽  
Bixuan Che ◽  
...  
Keyword(s):  
Porous Media ◽  
Performance Improvement ◽  
Porous Glass ◽  
Borosilicate Glass ◽  
Positive Impact ◽  
Processing Technique ◽  
The Novel ◽  
Machine Method ◽  
And Performance

The porous-media-based electrospray thruster is a cutting-edge micropropulsion technology that can revolutionize the capabilities of microsatellites. This paper reports the design, fabrication, and characterization of a novel porous-media borosilicate glass electrospray thruster. The porous glass used here is integrally formed by the phase separation method, which make it display outstanding pore uniformity and processability. The picosecond ultraviolet laser processing technique is applied to machine 361 emitters out of glass. Performance characteristic experiments are conducted with the thruster passively fed with ionic EMI-BF4 liquid. The results reveal that the per-emitter can emit up to 200.46 nA of ion current at 2 kV. The novel porous glass and the corresponding machine method present an opportunity to attain more-controllable emitter shapes, which has a positive impact on thruster lifetime and performance improvement.

scholarly journals Design and implementation of CNTFET based ternary 1x1 memories

2019 ◽  
Vol 8 (3) ◽  
pp. 175 ◽  
Author(s):  
S.Tamil Selvan ◽  
M. Sundararajan
Keyword(s):  
High Performance ◽  
Data Access ◽  
Cmos Technology ◽  
Access Time ◽  
The Novel ◽  
Design And Implementation ◽  
Technology Process ◽  
Sram Cell ◽  
And Performance ◽  
Power Application

In this paper presented Design and implementation of CNTFET based Ternary 1x1 RAM memories high-performance digital circuits. CNTFET Ternary 1x1 SRAM memories is implement using 32nm technology process. The CNTFET decresase the diameter and performance matrics like delay,power and power delay, The CNTFET Ternary 6T SRAM cell consists of two cross coupled Ternary inverters one is READ and another WRITE operations of the Ternary 6T SRAM cell are performed with the Tritline using HSPICE and Tanner tools in this tool is performed high accuracy. The novel based work can be used for Low Power Application and Access time is less of compared to the conventional CMOS Technology. The CNTFET Ternary 6T SRAM array module (1X1) in 32nm technology consumes only 0.412mW power and data access time is about 5.23ns.

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