Effects of partial exposure to lethal temperature on heterogeneously acclimated fish

1973 ◽  
Vol 51 (12) ◽  
pp. 1249-1255
Author(s):  
Fahmy K. Fahmy
Keyword(s):  
Brook Trout ◽  
Whole Body ◽  
Acclimation Temperature ◽  
Lethal Temperature ◽  
Tail Region ◽  
Mean Body Temperature ◽  
Individual Level ◽  
Time To Death ◽  
Different Temperatures ◽  
The One

Brook trout were acclimated either homogeneously, by exposing the whole body to the same temperature, or heterogeneously, by exposing the head and tail concurrently to two different temperatures in a divided chamber. After acclimation, one end of the fish was exposed to a lethal temperature (27.5C) while the other end was subjected to either 10 or 20C. The lethal response of any region of the fish varies with the acclimation temperature. For a heterogeneously acclimated fish, the cold-acclimated region when exposed to the lethal temperature reflected a mean body temperature effect, but when the warm-acclimated region was the one exposed, the time to death almost coincided with that of a fish wholly warm-acclimated and similarly exposed to the lethal temperature. When the head was exposed, death took place more rapidly when the tail region was at 20C than when it was at 10C. When the tail was exposed, death was slower when the head was at 20C than when it was at 10C. It is suggested that the tissue exposed responds according to its individual level of thermal acclimation.

Heterogeneous acclimation of fish to temperature

1972 ◽  
Vol 50 (7) ◽  
pp. 1035-1037 ◽  
Author(s):  
Fahmy K. Fahmy
Keyword(s):  
Central Nervous System ◽  
Brook Trout ◽  
Anatomical Site ◽  
Lethal Temperature ◽  
Time To Death ◽  
Different Temperatures ◽  
History Of ◽  
The Central Nervous System ◽  
The Mean ◽  
Total Tissue

Brook trout were acclimated heterogeneously for 3 weeks by exposing the head and tail simultaneously to two different temperatures. Time to death at a lethal temperature was taken as a measure of resistance acclimation. The relation between the resistance acclimation and mean temperature of the whole fish during acclimation indicated that the response of the whole organism depends on the mean thermal history of the total tissue regardless of the anatomical site. The mechanism through which a fish can acclimate to a higher or lower level of temperature is still unknown and whether the central nervous system has a direct or indirect role on such acclimation is not yet clear.

The influence of temperature on histological and radiochemical measurements of thyroid activity in the eastern brook trout, Salvelinus fontinalis Mitchell

1968 ◽  
Vol 46 (1) ◽  
pp. 1-9 ◽  
Author(s):  
D. E. Drury ◽  
J. G. Eales
Keyword(s):  
Epithelial Cell ◽  
Brook Trout ◽  
Salvelinus Fontinalis ◽  
Acclimation Temperature ◽  
Thyroid Follicle ◽  
Thyroid Activity ◽  
Cell Height ◽  
Different Temperatures ◽  
Influence Of Temperature On ◽  
T Values

Histological and radiochemical techniques for assessing thyroid activity were compared on yearling brook trout acclimated at 5, 12, and 15 °C.The mean thyroid follicle epithelial cell height was 7.4 μ (range 6.0–8.6 μ) at 5 °C; 3.5 μ (range 2.9–3.9 μ) at 12 °C, and 2.3 μ (range 1.9–2.9 μ) at 15 °C. Assuming that a taller epithelial cell height indicates greater thyroid activity, then an inverse relationship between thyroid activity and acclimation temperature exists.Both the uptake of radioiodide by the thyroid (T/S) and the clearance of radioiodide from the serum were greater at higher temperatures. Serum PB125I production was negligible within 8 days after radioiodide injection and the conversion ratio could not be applied as an index of thyroid function, Assuming, however, that the thyroid radioiodide uptake is an index of thyroid activity, then there is a direct relationship between thyroid activity and acclimation temperature.In view of the marked discrepancy between these histological and radiochemical techniques, fractional rates of turnover of serum thyroxine were compared by determining the biological half-life (t½) for serum PB125I after L-thyroxine-125I intraperitoneal injection at different temperatures. The serum PB125I clearance curves were complex and tentative t½ values of 18.0 days (5 °C, 3.2 days (12 °C), and 1.5 days (15 °C) were obtained. These results indicate a more rapid serum PBI turnover at higher temperatures and support the radiochemical measurements.

Static and Dynamic Studies of Gasoline in View of its Octane Number and its Toxic Effect

2013 ◽  
Vol 12 (7) ◽  
pp. 451-459
Author(s):  
Ashraf Yehia El-Naggar ◽  
Mohamed A. Ebiad
Keyword(s):  
Toxic Effect ◽  
Aromatic Hydrocarbons ◽  
Octane Number ◽  
Liquid Fuel ◽  
Positive Impact ◽  
Hydrocarbon Composition ◽  
Different Temperatures ◽  
Different Seasons ◽  
The One ◽  
The Impact

Gasoline come primarily from petroleum cuts, it is the preferred liquid fuel in our lives. Two gasoline samples of octane numbers 91 and 95 from Saudi Arabia petrol stations were studied. This study was achieved at three different temperatures 20oC, 30oC and 50oC representing the change in temperatures of the different seasons of the year. Both the evaporated gases of light aromatic hydrocarbons (BTEX) of gasoline samples inside the tank were subjected to analyze qualitatively and quantitatively via capillary gas chromatography. The detailed hydrocarbon composition and the octane number of the studied gasoline samples were determined using detailed hydrocarbon analyzer. The idea of research is indicating the impact of light aromatic compounds in gasoline on the toxic effect of human and environment on the one hand, and on octane number of gasoline on the other hand. Although the value of octane number will be reduced but this will have a positive impact on the environment as a way to produce clean fuel.

Is Distance to Drop Box an Appropriate Proxy for Drop Box Treatment? A Case Study of Washington State

2021 ◽  
pp. 1532673X2110221
Author(s):  
Loren Collingwood ◽  
Benjamin Gonzalez O’Brien
Keyword(s):  
United States ◽  
Voter Turnout ◽  
The United States ◽  
Washington State ◽  
Individual Level ◽  
Primary 52 ◽  
The One ◽  
Vote By Mail

In the United States, drop box mail-in voting has increased, particularly in the all vote by mail (VBM) states of Washington, Colorado, Utah, and Oregon. To assess if drop boxes improve voter turnout, research proxies box treatment by voters’ residence distance to nearest drop box. However, no research has tested the assumption that voters use drop boxes nearest their residence more so than they do other drop boxes. Using individual-level voter data from a 2020 Washington State election, we show that voters are more likely to use the nearest drop box to their residence relative to other drop boxes. In Washington’s 2020 August primary, 52% of drop box voters in our data used their nearest drop box. Moreover, those who either (1) vote by mail, or (2) used a different drop box from the one closest to their residence live further away from their closest drop box. Implications are discussed.

scholarly journals The Small and Efficient Language Network of Polyglots and Hyper-polyglots

2020 ◽  
Vol 31 (1) ◽  
pp. 62-76
Author(s):  
Olessia Jouravlev ◽  
Zachary Mineroff ◽  
Idan A Blank ◽  
Evelina Fedorenko
Keyword(s):  
Foreign Language ◽  
Language Processing ◽  
Default Mode Network ◽  
Individual Level ◽  
Neural Architecture ◽  
Initial Characterization ◽  
The One ◽  
Multiple Languages ◽  
Language Network

Abstract Acquiring a foreign language is challenging for many adults. Yet certain individuals choose to acquire sometimes dozens of languages and often just for fun. Is there something special about the minds and brains of such polyglots? Using robust individual-level markers of language activity, measured with fMRI, we compared native language processing in polyglots versus matched controls. Polyglots (n = 17, including nine “hyper-polyglots” with proficiency in 10–55 languages) used fewer neural resources to process language: Their activations were smaller in both magnitude and extent. This difference was spatially and functionally selective: The groups were similar in their activation of two other brain networks—the multiple demand network and the default mode network. We hypothesize that the activation reduction in the language network is experientially driven, such that the acquisition and use of multiple languages makes language processing generally more efficient. However, genetic and longitudinal studies will be critical to distinguish this hypothesis from the one whereby polyglots’ brains already differ at birth or early in development. This initial characterization of polyglots’ language network opens the door to future investigations of the cognitive and neural architecture of individuals who gain mastery of multiple languages, including changes in this architecture with linguistic experiences.

scholarly journals An enquiry concerning the nature of heat, and the mode of its communication

1832 ◽  
Vol 1 ◽  
pp. 139-147
Keyword(s):  
Principal Part ◽  
Cylindrical Vessel ◽  
The Other ◽  
Metallic Surface ◽  
Previous Trial ◽  
Flat Surfaces ◽  
Different Temperatures ◽  
The One ◽  
Quantity Of Heat

The importance of the investigation here entered into,—inasmuch as it applies to most of the operations of nature as well as art,—appears so manifest, that we shall not recapitulate what the author advances on that subject. Before he proceeds to the detail of his experiments for the purpose of computing the emissions of heat from various bodies under a variety of circumstances, he finds it necessary to premise a minute description of the principal part of the apparatus he contrived for his purpose. This instrument consists of a hollow cylindrical vessel of brass, four inches long, and as many in diameter. It is closed at both ends; but has at one end a cylindrical neck about eight-tenths of an inch in diameter, by which it is occasionally filled with water of different temperatures, and through which also a thermometer, constructed for the purpose, is occasionally introduced, in order to ascertain the changes of temperature in the fluid. As it was in the first instance only meant to observe the quantity of heat that escapes through the sides of the vessel, two boxes were contrived, filled and covered with non-conducting substances, such as eiderdown, fur, &c., which were fitted to the two ends or flat surfaces of the cylinder. Six of these instruments, with proper stands, and auxiliary implements of obvious construction, were prepared for the sake of comparative experiments. A previous trial was made with two of the cylinders, the vertical polished sides of the one being naked, and those of the other covered with one thickness of fine white Irish linen, strained over the metallic surface. Here it was found, contrary to expectation, that in a certain space of time the covered cylinder had lost considerably more heat than the naked one.

Caudal Fin and Body Movement in the Propulsion of some Fish

1963 ◽  
Vol 40 (1) ◽  
pp. 23-56 ◽  
Author(s):  
RICHARD BAINBRIDGE
Keyword(s):  
Body Movement ◽  
Wave Length ◽  
The Body ◽  
Whole Body ◽  
Tail Region ◽  
Caudal Fin ◽  
A Value ◽  
Total Thrust ◽  
Transverse Movement ◽  
Relationship Of

1. Observations made on bream, goldfish and dace swimming in the ‘Fish Wheel’ apparatus are described. These include: 2. An account of the complex changes in curvature of the caudal fin during different phases of the normal locomotory cycle. Measurements of this curvature and of the angles of attack associated with it are given. 3. An account of changes in area of the caudal fin during the cycle of lateral oscillation. Detailed measurements of these changes, which may involve a 30 % increase in height or a 20 % increase in area, are given. 4. An account of the varying speed of transverse movement of the caudal fin under various conditions and the relationship of this to the changes in area and amount of bending. Details of the way this transverse speed may be asymmetrically distributed relative to the axis of progression of the fish are given. 5. An account of the extent of the lateral propulsive movements in other parts of the body. These are markedly different in the different species studied. Measurements of the wave length of this movement and of the rate of progression of the wave down the body are given. 6. It is concluded that the fish has active control over the speed, the amount of bending and the area of the caudal fin during transverse movement. 7. The bending of the fin and its changes in area are considered to be directed to the end of smoothing out and making more uniform what would otherwise be an intermittent thrust from the oscillating tail region. 8. Some assessment is made of the proportion of the total thrust contributed by the caudal fin. This is found to vary considerably, according to the form of the lateral propulsive movements of the whole body, from a value of 45% for the bream to 84% for the dace.

scholarly journals A Study on the Kinetics and Mechanism of the One-Pot Formation of 3,4,5-Substituted Furan-2(5H)-Ones in the Presence of Lactic Acid: Effect of Different Substituents

2018 ◽  
Vol 43 (3-4) ◽  
pp. 286-299 ◽  
Author(s):  
Osman Asheri ◽  
Sayyed Mostafa Habibi-Khorassani ◽  
Mehdi Shahraki
Keyword(s):  
Lactic Acid ◽  
Activation Parameters ◽  
General Mechanism ◽  
Common Mechanism ◽  
Substituted Anilines ◽  
One Pot ◽  
Isokinetic Relationship ◽  
Zero Order Kinetics ◽  
Different Temperatures ◽  
The One

The kinetics of the reaction between para-substituted anilines and dimethyl acetylenedicarboxylate (DMAD) with derivatives of benzaldehyde for the one-pot formation of 3,4,5-substituted furan-2(5 H)-ones in the presence of lactic acid as a catalyst have been studied spectrophotometrically at different temperatures. A mechanism involving four steps was proposed for the reactions, all of which followed second-order kinetics. The partial orders with respect to substituted aniline and DMAD were one and one and the reactions revealed zero-order kinetics for benzaldehyde and its derivatives. Changing of substituents on benzaldehyde left rates of reaction unaffected. However, various substituents on aniline showed that para electron-withdrawing groups decreased the rate of reaction. According to investigation of an isokinetic relationship, a common mechanism exists for all studied substituents and a general mechanism can be formulated. Kinetic values ( k and Ea) and associated activation parameters (Δ G‡, Δ S‡ and Δ H‡) of the reactions were determined.

nr="93"Black Box rules. : Narrative der Verunsicherung in Zeiten von COVID-19

2021 ◽  
Vol 2019 (1) ◽  
pp. 93-107
Author(s):  
Agnieszka Czejkowska ◽  
Katarina Froebus
Keyword(s):  
Black Box ◽  
The Other ◽  
Individual Level ◽  
Home Security ◽  
Other Hand ◽  
Innere Sicherheit ◽  
The One

Zusammenfassung: Der vorliegende Beitrag widmet sich Narrativen der Verunsicherung, die in Zusammenhang mit der COVID-19-Krise aufgerufen werden und für ,,innere Sicherheit“ sorgen sollen. Dabei identifizieren wir Kalküle, die einerseits individuelle Besonnenheit aktivieren und anderseits gesellschaftliche Stabilisierung gewährleisten sollen. Das gelingt uns mit Rückgriff auf psychoanalytische Subjekttheorien, die Strategien der individuellen Rationalisierung fokussieren, und auf diskursorientierte Subjekttheorien, die gesellschaftliche Disziplinierungstechnologien in den Blick nehmen.Abstract: This article is focused on narratives of uncertainness, being created during the COVID-19 crisis in order to provide ‘home security’. In doing so, we identify approaches that on the one hand activate individual level-headedness and on the other hand are supposed to ensure societal stabilization. We succeed in doing this by resorting to psychoanalytic subject theories that emphasize strategies of individual rationalization and to discourse-oriented subject theories that accent social disciplinary technologies.

An appropriate biomechanical model of seated human subjects exposed to whole-body vibration

2021 ◽  
pp. 146441932110394
Author(s):  
Raj Desai ◽  
Anirban Guha ◽  
Pasumarthy Seshu
Keyword(s):  
Degrees Of Freedom ◽  
Human Subjects ◽  
Computational Cost ◽  
Biomechanical Model ◽  
Whole Body ◽  
Body Parts ◽  
Lumped Parameter ◽  
Long Duration ◽  
The One ◽  
The Right

Long duration automobile-induced vibration is the cause of many ailments to humans. Predicting and mitigating these vibrations through seat requires a good model of seated human body. A good model is the one that strikes the right balance between modelling difficulty and simulation results accuracy. Increasing the number of body parts which have been separately modelled and increasing the number of ways these parts are connected to each other increase the number of degrees of freedom of the entire model. A number of such models have been reported in the literature. These range from simple lumped parameter models with limited accuracy to advanced models with high computational cost. However, a systematic comparison of these models has not been reported till date. This work creates eight such models ranging from 8 to 26 degrees of freedom and tries to identify the model which strikes the right balance between modelling complexity and results accuracy. A comparison of the models’ prediction with experimental data published in the literature allows the identification of a 12 degree of freedom backrest supported model as optimum for modelling complexity and prediction accuracy.

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