Top PDF Thermal stress on intertidal limpets: long term hindcasts and lethal limits

Thermal stress on intertidal limpets: long term hindcasts and lethal limits

Thermal stress on intertidal limpets: long term hindcasts and lethal limits

The recent advent of small self-contained data loggers has revolutionized this process. For example, self-contained data loggers mounted in plastic models of the mussel Mytilus californianus Conrad were used to measure lengthy time series of body temperatures at multiple sites from California to Washington state (Helmuth et al., 2002), and data loggers were used to measure the temperature of the rock surface, an accurate surrogate for the temperature of acorn barnacles (Wethey, 2002; Harley and Lopez, 2003). These new techniques have their limitations, however. The current generation of data loggers (TidbiTs; Onset Computers, Bourne, MA, USA, and iButtons; Dallas Semiconductor, Dallas, TX, USA) are too large to fit into most intertidal algae and snails, and the temperatures of these organisms are likely to be different from that of the rock surface. Consequently, detailed, long-term thermal histories of these and other ecologically important intertidal species are still out of reach.
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Physiological responses to short term thermal stress in mayfly (Neocloeon triangulifer) larvae in relation to upper thermal limits

Physiological responses to short term thermal stress in mayfly (Neocloeon triangulifer) larvae in relation to upper thermal limits

Taken collectively, our results suggest that although the OCLTT hypothesis may be appropriate for explaining responses to rapid short-term warming, it does not explain thermal limits in the mayfly N. triangulifer at temperatures that are chronically lethal, and perhaps more ecologically relevant. Respirometry experiments revealed no change in aerobic scope at temperatures that bracketed the chronic thermal limits of this species, and gene expression experiments showed marked differences between responses to heat and hypoxia and little evidence for widespread expression of hypoxia responsive genes at temperatures up to the ecologically relevant limit. Although the data presented here represent physiological responses to short-term thermal change, ongoing studies are evaluating gene expression and metabolomics changes in chronically reared mayflies. These processes are important to understand, particularly in relation to understanding responses to multiple stressors, which are predominant in natural ecosystems (Buchwalter et al., 2003; Piggott et al., 2012; Sokolova et al., 2006). However, our results do suggest that oxygen limitation may indeed play a significant role when N. triangulifer larvae are warmed beyond their ecologically relevant thermal limit up to their acutely tolerated temperatures. It is also possible that the respiratory challenge observed during the molt (Camp et al., 2014) may introduce transient oxygen limitation, which may become more important as larvae age. The field of toxicology has long realized that mechanisms associated with acute and chronic toxicity may be very different. Our data suggest that the same is likely true for temperature.
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Upper thermal limits of growth in brook trout and their relationship to stress physiology

Upper thermal limits of growth in brook trout and their relationship to stress physiology

Our results indicate a decline in growth rate as temperature increases above 16°C in brook trout, and that the upper limit for their positive growth is 23.5°C. These results are in line with an extensive literature suggesting optimal growth of brook trout between 13°C and 16°C (Baldwin, 1956; Hokanson et al., 1973; Dwyer et al., 1983). None of these studies incorporated enough treatments above the optimal temperature to adequately describe brook trout growth at elevated temperatures. Nor did they test temperatures high enough to determine the upper limit for growth in brook trout. Wehrly et al. (2007) reported that brook trout are not found in waters above a 24 day mean maximum temperature of 22°C despite the fact that the lethal temperature in this species is 25.3°C (Fry et al., 1946; Fry, 1951; Wehrly et al., 2007). The fact that the ecological limit is more closely associated with temperature limitations on growth than it is with the lethal temperature suggests that temperature limitations on growth may play a key role in determining brook trout distributions. In the current study, individually marked fish and near continuous monitoring of temperature were used to provide a clear indication of the relationship between temperature and growth. It should be noted that ‘ tank effects ’ (uncontrolled variables that affect an entire tank) can have impacts on growth rate in long-term experiments (Speare et al., 1995). Because even small differences in temperature accumulated over several weeks can impact growth, we chose to use a broad range of temperatures and a regression approach rather than replicate a small number of temperatures. This allowed us to more accurately determine the shape of the growth curve and relate it to physiological parameters. Using the same tank system as in Experiment 1, we found no evidence of tank effects in Experiment 2 at either constant or fluctuating temperatures. The accuracy of this approach is further supported by the strong correspondence between the specific growth rate of 1.95% day –1 found for nominal temperature 21°C in Experiment 2 and 1.75% day –1 that was predicted for this temperature by the growth curve from Experiment 1 (Fig. 2C).
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Biophysics, environmental stochasticity, and the evolution of thermal safety margins in intertidal limpets

Biophysics, environmental stochasticity, and the evolution of thermal safety margins in intertidal limpets

Several other types of basic information are needed at the level of genetics. For simplicity, our genetic model links the lethal thermal limit to the level of constitutive defense of the individual. There is some indirect evidence to support this assumption in limpets. In a study of four species of intertidal limpets at Hopkins Marine Station, Dong and colleagues (Dong et al., 2008) found that the two species that grow high on the shore maintained higher constitutive levels of Hsp70 than the two low-shore species. Wolcott (Wolcott, 1973) found that the same two high-shore species had higher thermal limits than the two low-shore species. However, this correlation falls well short of demonstrating that constitutive defenses and thermal limits are genetically linked within a species. A combination of genomic (allele frequencies), functional-genomic (gene and protein expression patterns), biochemical (protein functional analyses) and organismal approaches are urgently needed in this context. For example, it is possible (perhaps likely) that constitutive and acute thermal tolerance costs are associated with different gene products and pathways or that different levels of thermal stress require different suites of responses (e.g. Logan and Somero, 2010; Logan and Somero, 2011; Whitehead, 2012). Similarly, an investigation of the ratio of induced to constitutive thermal tolerance costs, and how that ratio might vary as a function of genotype and thermal history, would provide crucial information.
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The effect of long term exposure on thermal performance of roofing materials in Malaysian climatic condition

The effect of long term exposure on thermal performance of roofing materials in Malaysian climatic condition

Concrete and clay roofing tile; the most commonly used roofing materials in this region have a very durable service life due to their ability to withstand the weather conditions. Unfortunately, not much attention is paid to its thermal performance in the long run (Kiet et al., 2008). Studies on roof materials have shown that the change in albedo over time will vary inconsistently between roofs depending on the climatic and atmospheric condition amidst other factors (Bretz & Akbari, 1997). However, it is possible to determine an average pattern of behavior for a geographical area. The summary of literature reviewed reveals that quite a lot of studies have been carried out in various climatic regions and a number of testing methods used to analyze some performance criteria of building envelope elements. Hence, a time related thermal performance of roofing materials in tropical regions is a welcome contribution to the existing body of knowledge.
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Assessment of Long Term Thermal Stress on Egyptian Coral Reefs Based on Remotely Sensed Sea Surface Temperature Data

Assessment of Long Term Thermal Stress on Egyptian Coral Reefs Based on Remotely Sensed Sea Surface Temperature Data

Newbaa and increases to 30.79 in the most south part in Shalatin. The work proved that there were some bleaching events in the last 23 years which weren't locally properly recorded such as 1999 and 2007 in some locations. In addition, the results showed an agreement with the recent recorded bleaching events in 2010, 2012. These results can act as a good reference for marine biologists who are interested in the historical bleaching events in the Egyptian coral reefs. The study reveals unique patterns of sea surface temperature in the western different from eastern part of the Red sea on the same latitude. This pattern need further research in terms of water movements. The applied framework in this study takes into account only the thermal stress so the study can be further enhanced by examining the local water flow patterns using any hydrodynamic modeling tools.
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Temperature Acclimation: Influence on Transient Outward and Inward Currents in an Identified Neurone of Helix Pomatia

Temperature Acclimation: Influence on Transient Outward and Inward Currents in an Identified Neurone of Helix Pomatia

To gain insight into the mechanisms underlying compensatory changes in excitability induced by thermal acclimation we examined the effects of short-term and long-term temperature transit[r]

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Stress and Perception of Emotional Stimuli: Long-term Stress Rewiring the Brain

Stress and Perception of Emotional Stimuli: Long-term Stress Rewiring the Brain

In this study, long-term mental stress level of a subject is estimated by PSS-14 questionnaire (Cohen, Kamarck, & Mermelstein, 1983) that comprises 14 items. In each item, subject is asked how often he/she has experienced certain occurrence of a stressful situations during the last month. Response for each item is scored from 0 to 4, thus total re- sponse scores range from 0 to 56. A higher response score correlates with a higher level of mental stress. However, there is no score cut-off point and comparisons are only sample-wise. In this study, subjects’ responses to PSS-14 had mean and standard deviation of µ=24, σ=6.7 respec- tively. Subjects with a score lower than µ-σ/2=21 were considered to be relatively stress-free whereas those with a score higher than µ+σ/2=28 were considered to have long-term stress.
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Prediction of seasonal climate-induced variations in global food production

Prediction of seasonal climate-induced variations in global food production

In contrast, the levels of rice exports that were reliably predicted were far lower than those of wheat exports when the yield hindcasts were evaluated but were comparable when the crop failure hindcasts were assessed (Table S1). Notably, a considerable extent of the predictable area (52-78% of the national harvested area) found in the third-major rice exporter, Uruguay, contributed to results in such values for predicting the rice yield losses (Fig. S11). The second-major rice exporter, Thailand, exhibited even less predictable area (3% of the national harvested area); although Thailand is located in the tropics, this result is likely due to the lack of crop calendar data for the triple cropping systems under operation in that region 21, 22 and the higher sensitivity of yields to soil moisture conditions (Fig. 4).
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Experimental study on long-term thermal effects on concrete

Experimental study on long-term thermal effects on concrete

Regarding the mechanism of heating on the mechanical properties of concrete, it is revealed from the results of present experiment that, when free water exists, hydration and crystallization proceed and the mechanical properties increase with heating. In addition, by comparing the water content ratio and the mechanical properties of MDL and the specimen, it is found that the transition of free water is slow at the high temperature part of MDL, and the change in the mechanical properties with heating is close to the sealed specimen. The transition of free water of MDL of this study is considered to be faster than the concrete which receives long-term heating in the nuclear power plant, as the following reason. ・While the heating temperature in this study is 90 °C, the maximum temperature of concrete in the
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LONG-TERM ON-ORBIT THERMAL PERFORMANCE OF AEROGEL INSULATION

LONG-TERM ON-ORBIT THERMAL PERFORMANCE OF AEROGEL INSULATION

The last set of on-orbit aerogel thermal data collected by AFRL was made on August 25 2013. Aerogel has since been evaluated in- house as a radiative barrier using a guarded hot plate method (Irick, 2017) which shows performance comparable to a range of 5-layer to 10-layer MLI blankets. The ground testing results, along with the durability, low cost of handling and integration, and low density of aerogel, make aerogel a competitive alternative to traditional MLI as an aerospace thermal insulator.

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Regulating private pension funds’ structure, performance and investments: cross country evidence

Regulating private pension funds’ structure, performance and investments: cross country evidence

Section 5.3.1 showed the rate of return to pension funds in Latin America relative to market returns. A comparable analysis for the United Kingdom and the United States, both of which have prudent-person rules rather than asset limits, is instructive. Lakonishok, Shleifer and Vishny (1992) investigated the performance of defined-benefit pension funds relative to the Standard & Poors 500 over the period 1983-89. Weighting each funds return equally, the average return fell 1.3 percentage points below the index return of 19 per cent. Weighting funds by value, the under-performance was 2.6 percentage points. Over the same period, other institutional investors, such as mutual funds, outperformed the market. Since there are no asset limits, this under-performance should arise from some other structural factors such as market failure.
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<p>The Long-Term Effects of Adolescent Social Defeat Stress on Oligodendrocyte Lineage Cells and Neuroinflammatory Mediators in Mice</p>

<p>The Long-Term Effects of Adolescent Social Defeat Stress on Oligodendrocyte Lineage Cells and Neuroinflammatory Mediators in Mice</p>

Recently, the underlying biological and neurobiological mechanisms mediating the effect of childhood and adoles- cent adversities on psychopathology vulnerability have been scrutinized. Some of the persistent biological altera- tions were associated with childhood and adolescent adversities, such as changes in neuroendocrine, neuro- transmitter systems and immune system. These individual changes may interact with each other and contribute to speci fi c alterations in brain structures and functions involved in cognitive and emotional regulation. 60,61 Microglia express diverse receptors, which permit them to integrate and response to stress-induced hormones, neural and immune products including glucocorticoids, corticotropin-releasing factor and cytokines. 62,63 The evi- dence also exists showing that OL development and mye- lination are in fl uenced by stress hormones. 32,64 While the present study focused on the role of microglia and cyto- kines in the myelin pathology, future research should address the interactions between neuroendocrine and immune system under the myelin pathology condition induced by the early life stress.
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Hormonal response of Arctic fox females to short  and long term stress

Hormonal response of Arctic fox females to short and long term stress

Long-term stress, combined with adaptation to new environmental conditions, was examined in 30 females (one-year old), purchased from the farm in the Lodzkie province (farm B). The testing proce- dure involved selection and capture of the animals placed in two-row pavilions (using neck tongs), their immobilisation and transfer from the pavilion, blood collection and the placement of each animal in a transport cage, which was then loaded onto a truck. The transport of purchased animals to the target farm (farm A) lasted approximately 8 h. After trans- fer to farm A where the experiment was conducted, the animals were individually placed in cages (200 × 100 × 80 cm). Blood from the animals was col- lected five times in total, i.e. before transport (on the original farm), directly after the transfer to the new farm, and after three days, while the last two samplings were conducted at 5- and 15-day intervals from the third blood collection.
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Long term Adaptations of Sabella Giant Axons to Hyposmotic Stress

Long term Adaptations of Sabella Giant Axons to Hyposmotic Stress

This increase partially compensates for the reduction in sodium gradient across the axon membrane, during dilution of the bathing media, by increasing the overshoot of the action potenti[r]

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Effects of P element insertions on quantitative traits in Drosophila melanogaster.

Effects of P element insertions on quantitative traits in Drosophila melanogaster.

gous lethal chromosomes with large heterozygous ef- fects on bristle traits have been recovered commonly from long-term Drosophila bristle selection lines, where they caus[r]

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Thermal physiology of the fingered limpet Lottia digitalis under emersion and immersion

Thermal physiology of the fingered limpet Lottia digitalis under emersion and immersion

At temperatures greater than 20°C, immersed limpets appear to be suppressing their metabolic rate as temperature is increased. This suggests immersed limpets may not be able to maintain the oxygen supply necessary to meet the metabolic demand of increasing temperature (Pörtner, 2001) and may be relying increasingly on anaerobic metabolism. Glycogen levels measured in the present study in foot tissue, the primary site of glycogen storage (Santini and Chelazzi, 1995), did not change significantly in response to increasing temperature under immersion until 40°C, where they were significantly lower than levels at 15 and 25°C. Therefore, it does not appear that immersed limpets are increasing anaerobic pathways and depleting glycogen at temperatures where they have reduced M O2 . Our results are consistent with a previous study in the intertidal snail E. malaccana in response to increasing temperature stress under emersion (Marshall et al., 2011). Echinolittorina malaccana depressed aerobic metabolism in response to prolonged temperature exposures to conserve energy; however, they avoided undergoing anaerobic metabolism (Marshall et al., 2011). Though patterns are variable, some animals have been shown to partition energy demands between aerobic and anaerobic metabolism using anaerobic pathways that lead to end products of succinate, alanine and propionate (Truchot, 1990; Santini et al., 2001). The ribbed mussel Mytilus californianus has been shown to oscillate between aerobic and anaerobic metabolites in relation to the tidal cycle, where anaerobic metabolites and catabolism of fatty acids increase and aerobic metabolites decrease during low tide emersion (Connor and Gracey, 2012).
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An adjuvanted inactivated murine cytomegalovirus (MCMV) vaccine induces potent and long term protective immunity against a lethal challenge with virulent MCMV

An adjuvanted inactivated murine cytomegalovirus (MCMV) vaccine induces potent and long term protective immunity against a lethal challenge with virulent MCMV

The long-term protection provided by the three adju- vanted vaccines was compared. When challenged with a lethal dose of SG-MCMV at 6 months post-immunization, MF59-treated mice were protected, with a survival rate of 93% (13/14). The alum-adjuvanted group had a survival rate of 86% (12/14). In comparison, chitosan had a less sat- isfactory adjuvant effect, with a survival rate of 43% (6/14). These results strongly suggest that immunization with adjuvanted FI-MCMV vaccine elicits a stronger protective immune response and can provide longer protection than immunization with adjuvant-free vaccine. From the per- spective of long-term protection, adjuvant MF59 had simi- lar efficacy as Alum, both of which were slightly superior to chitosan. However, all conferred significantly better protec- tion than the adjuvant-free vaccine.
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The proteomic response of the mussel congeners Mytilus galloprovincialis and M  trossulus to acute heat stress: implications for thermal tolerance limits and metabolic costs of thermal stress

The proteomic response of the mussel congeners Mytilus galloprovincialis and M trossulus to acute heat stress: implications for thermal tolerance limits and metabolic costs of thermal stress

A number of studies have started to characterize the proteomic response of Mytilus congeners to stresses, such as oxidative stress and pollutant exposure (Apraiz et al., 2006; McDonagh and Sheehan, 2007). Other studies have focused on the variation in the proteome in eggs and hybrids (Diz and Skibinski, 2007) or compared M. edulis with M. galloprovincialis acclimatized to temperature conditions of their respective geographic ranges (López et al., 2002). However, the present study is the first comprehensive comparison of the proteomic response to acute heat stress between any pair of Mytilus congeners, notably a pair whose biogeographic ranges are in flux. We used a proteomics approach based on two-dimensional gel electrophoresis (2-D GE) to provide a global perspective on how protein abundance changes, either due to changes in expression (i.e. synthesis), post-translational modifications (PTMs) or degradation in response to heat stress in the two mussel congeners. Using an expressed sequence tag (EST) library generated by various transcriptomic projects (Gracey et al., 2008; Lockwood et al., 2010) and tandem mass spectrometry (MS), we were able to identify a number of proteins that showed differential expression profiles in response to acute heat shock.
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Short and long Term behavior of Knowledge

Short and long Term behavior of Knowledge

The above illustrations, figure 10 and 11 demonstrate to us the long term behaviour of knowledge. Now it can be appreciated why at first it was necessary for us to discuss the short term properties of knowledge, they would make our long term discussions of knowledge more simplistic. The long term properties of knowledge is that it increases at an ever faster rate. Whilst the short term increases of knowledge are limited, there is so much one/ a society can extract from a single point of knowledge, in the long term there are no real limits to knowledge as such, the limit theoretically is that a society knows everything.
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