scholarly journals TEMPERATURE AND CRITICAL ILLUMINATION FOR REACTION TO FLICKERING LIGHT

1939 ◽  
Vol 22 (4) ◽  
pp. 487-499 ◽  
Author(s):  
W. J. Crozier ◽  
Ernst Wolf

For the sunfish Enneacanthus the mean value of the critical illumination for response to visual flicker at constant flash frequency (with light time = dark time) is related to temperature by the Arrhenius equation. The temperature characteristic for 1/Im is different above and below 20°C. In each range (12° to 20°; 20° to 30°) the temperature characteristic is the same for rod and cone segments of the duplex flicker response contour: 8,200 and 14,400. This makes it difficult, if not impossible, to consider that the two groups of elements are organized in a significantly different way chemically. For the presumptively rod-connected elements implicated in response to flicker, the curve is markedly discontinuous, so that the high and low temperature parts are dislocated; whereas for the cones they are not. This is entirely consistent with other (e.g., genetic) evidence pointing to their separate physical substrata. The uncommon exhibition of a higher µ over a higher range of temperature, previously found, however, in a few cases, together with the different relations of rod and cone effects to the critical temperature, explain aspects of these data which in earlier incomplete measurements were found to be puzzling.

1932 ◽  
Vol 16 (1) ◽  
pp. 65-73 ◽  
Author(s):  
Pei-Sung Tang

The rate of anaerobic production of CO2 by germinating seeds of Lupinus albus was studied as a function of temperature between 7.5° and 18°C. The mean value for the temperature characteristic was found to be 21,500± calories, which is slightly lower than that for the same process under aerobic conditions (23,500± calories). The values for the individual µ's in the two cases overlap considerably. The possible identity of the processes underlying the production of CO2 aerobically and anaerobically is discussed.


Minerals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 294 ◽  
Author(s):  
Anna Firstova ◽  
Tamara Stepanova ◽  
Anna Sukhanova ◽  
Georgy Cherkashov ◽  
Irina Poroshina

The Semyenov-2 hydrothermal field located at 13°31′N of the Mid-Atlantic Ridge (MAR) is associated with an oceanic core complex (OCC) and hosted by peridotites and basalts with minor amounts of gabbro and plagiogranites. Seafloor massive sulphides (SMS) are represented by chimneys with zonality, massive sulphides without zonality and sulphide breccia cemented by opal and aragonite. The mean value of Au (20.6 ppm) and Te (40 ppm) is much higher than average for the MAR SMS deposits (3.2 ppm and 8.0 ppm, respectively). Generally, these high concentrations reflect the presence of a wide diversity of Au and Te minerals associated with major mineral paragenesis: primary native gold, melonite (NiTe2) and tellurobismuthite (Bi2Te3) are related to high-temperature chalcopyrite (~350 °C); electrum (AuAg)1, hessite (Ag2Te) and altaite (PbTe) are related to medium- and low-temperature Zn-sulphide and opal assemblages (260–230 °C). Calaverite (AuTe2) and Te-rich “fahlore” Cu12(Sb,As,Te)4S13 are texturally related to the chalcopyrite-bornite-covellite. Enrichment of Au in sulphide breccia with opal and aragonite cement is driven by the re-deposition and the process of hydrothermal reworking of sulphide. The low-temperature fluid mobilizes gold from primary sulphide, along with Au and Te minerals. As a result, the secondary gold re-precipitate in cement of sulphide breccia. An additional contribution of Au enrichment is the presence of aragonite in the Cu-Zn breccia where the maximal Au content (188 ppm) is reached.


1939 ◽  
Vol 23 (2) ◽  
pp. 143-163 ◽  
Author(s):  
W. J. Crozier ◽  
Ernst Wolf

For the teleosts Xiphophorus montezuma, Platypoecilius maculatus, and their F1 hybrids the temperature characteristics (µ in Arrhenius' equation) are the same for the shift of the low intensity and the high intensity segments of the respective and different flicker response contours (critical intensity I as a function of flash frequency F, with light time fraction constant, at 50 per cent). The value of µ is 12,500 calories or a very little less, over the range 12.5 to 36°. This shows that 1/I can be understood as a measure of excitability, with F fixed, and that the excitability is governed by the velocity of a chemical process common to both the classes of elements represented in the duplex performance curve (rods and cones). It is accordingly illegitimate to assume that the different shapes of the rod and cone branches of the curves are determined by differences in the chemical mechanisms of excitability. It is also forbidden to assume that the differing form constants for the homologous segments in the curves for two forms (X. and P.) are the reflections of a difference in the chemical factors of primary excitability. These differences are determined by statistical factors of the distribution of excitabilities among the elements implicated in the sensory effect vs. intensity function, and are independent of temperature and of the temperature characteristic. It must be concluded that the physicochemical nature of the excitatory process cannot be deduced from the shape of the performance contour. The form constants (σ'log I and Fmax.) for F vs. log I are specifically heritable in F1, although µ is here the same as for X. and P. In an intergeneric cross one cannot in general expect Mendelian simplicity of segregation in subsequent generations, and in the present case we find that F2 individuals are indistinguishable from F1, both as regards F vs. log I and as regards the variation of I within a group of 17 individuals. The result in F2 definitely shows, however, that certain specific statistical form constants for the F-log I contour are transmissible in inheritance. It is pointed out that there thus is provided an instance in which statistical (distribution) factors in performance characteristics involving the summating properties of assemblages of cellular units are heritable in a simple manner without the implication of detectable differences in chemical organization of the units involved. This has an important bearing upon the logic of the theory of the gene.


Author(s):  
Noriyuki Kuwano ◽  
Masaru Itakura ◽  
Kensuke Oki

Pd-Ce alloys exhibit various anomalies in physical properties due to mixed valences of Ce, and the anomalies are thought to be strongly related with the crystal structures. Since Pd and Ce are both heavy elements, relative magnitudes of (fcc-fpd) are so small compared with <f> that superlattice reflections, even if any, sometimes cannot be detected in conventional x-ray powder patterns, where fee and fpd are atomic scattering factors of Ce and Pd, and <f> the mean value in the crystal. However, superlattices in Pd-Ce alloys can be analyzed by electron microscopy, thanks to the high detectability of electron diffraction. In this work, we investigated modulated superstructures in alloys with 12.5 and 15.0 at.%Ce.Ingots of Pd-Ce alloys were prepared in an arc furnace under atmosphere of ultra high purity argon. The disc specimens cut out from the ingots were heat-treated in vacuum and electrothinned to electron transparency by a jet method.


1987 ◽  
Vol 26 (06) ◽  
pp. 253-257
Author(s):  
M. Mäntylä ◽  
J. Perkkiö ◽  
J. Heikkonen

The relative partition coefficients of krypton and xenon, and the regional blood flow in 27 superficial malignant tumour nodules in 22 patients with diagnosed tumours were measured using the 85mKr- and 133Xe-clearance method. In order to minimize the effect of biological variables on the measurements the radionuclides were injected simultaneously into the tumour. The distribution of the radiotracers was assumed to be in equilibrium at the beginning of the experiment. The blood perfusion was calculated by fitting a two-exponential function to the measuring points. The mean value of the perfusion rate calculated from the xenon results was 13 ± 10 ml/(100 g-min) [range 3 to 38 ml/(100 g-min)] and from the krypton results 19 ± 11 ml/(100 g-min) [range 5 to 45 ml/(100 g-min)]. These values were obtained, if the partition coefficients are equal to one. The equations obtained by using compartmental analysis were used for the calculation of the relative partition coefficient of krypton and xenon. The partition coefficient of krypton was found to be slightly smaller than that of xenon, which may be due to its smaller molecular weight.


1968 ◽  
Vol 20 (01/02) ◽  
pp. 044-049 ◽  
Author(s):  
B Lipiński ◽  
K Worowski

SummaryIn the present paper described is a simple test for detecting soluble fibrin monomer complexes (SFMC) in blood. The test consists in mixing 1% protamine sulphate with diluted oxalated plasma or serum and reading the optical density at 6190 Å. In experiments with dog plasma, enriched with soluble fibrin complexes, it was shown that OD read in PS test is proportional to the amount of fibrin recovered from the precipitate. It was found that SFMC level in plasma increases in rabbits infused intravenously with thrombin and decreases after injection of plasmin with streptokinase. In both cases PS precipitable protein in serum is elevated indicating enhanced fibrinolysis. In healthy human subjects the mean value of OD readings in plasma and sera were found to be 0.30 and 0.11, while in patients with coronary thrombosis they are 0.64 and 0.05 respectively. The origin of SFMC in circulation under physiological and pathological conditions is discussed.


1996 ◽  
Vol 75 (05) ◽  
pp. 772-777 ◽  
Author(s):  
Sybille Albrecht ◽  
Matthias Kotzsch ◽  
Gabriele Siegert ◽  
Thomas Luther ◽  
Heinz Großmann ◽  
...  

SummaryThe plasma tissue factor (TF) concentration was correlated to factor VII concentration (FVIIag) and factor VII activity (FVIIc) in 498 healthy volunteers ranging in age from 17 to 64 years. Immunoassays using monoclonal antibodies (mAbs) were developed for the determination of TF and FVIIag in plasma. The mAbs and the test systems were characterized. The mean value of the TF concentration was 172 ± 135 pg/ml. TF showed no age- and gender-related differences. For the total population, FVIIc, determined by a clotting test, was 110 ± 15% and the factor VIlag was 0.77 ± 0.19 μg/ml. FVII activity was significantly increased with age, whereas the concentration demonstrated no correlation to age in this population. FVII concentration is highly correlated with the activity as measured by clotting assay using rabbit thromboplastin. The ratio between FVIIc and FVIIag was not age-dependent, but demonstrated a significant difference between men and women. Between TF and FVII we could not detect a correlation.


1966 ◽  
Vol 16 (01/02) ◽  
pp. 038-050 ◽  
Author(s):  
Ulla Hedner ◽  
Inga Marie Nilsson ◽  
B Robertson

SummaryThe plasminogen content was determined by a casein method in plasma and serum from 20 normal volunteers. The mean plasminogen content was found to be 10.1 ACU (the arbitrary caseinolytic unit defined in such a way that using a 3% casein solution and a digestion time of 20 min. at 37°C, 10 ACU gave an extinction of 0.300). No difference between serum and plasma regarding the plasminogen content was found.Plasminogen was determined in drained and drained plus washed clots prepared from 2 ml plasma. The highest values found in the drained clots were 0.9 ACU/clot and 0.2 ACU/clot in the drained plus washed clots.Plasminogen was also determined in drained and drained plus washed clots prepared from plasma with added purified plasminogen. The plasminogen was recovered in the washing fluid. According to these tests, then, purified added plasminogen is washed out of the clots.The plasminogen content of 20 thrombi obtained post mortem was also determined. The mean value was found to be 0.7 ACU/cm thrombus. Judging from our results, the “intrinsic clot lysis theory” is not the main mechanism of clot dissolution.


2017 ◽  
Vol 4 (2) ◽  
pp. 14
Author(s):  
Putri Megasari

Hepatitis has become a health problem in the world. The hepatitis virus infected many people. According to the teacher of MTsN 02 Bondowoso more than 20 students have hepatitis A viral infection. The purpose of this research was to know the differences of students' knowledge about hepatitis A before and after counseling in MTsN 02 Bondowoso 2015. This study used pre-experimental (pre-post test design). This study used stratified random sampling technique, 127 students from 270 sample involved this research,and 143 students was excluded. We used questionnaires to collect data. The results showed that the mean value of the students 'knowledge about hepatitis A before counseling in MTsN 02 Bondowoso 2015 was 83.96 with the lowest value of 37.5 and the highest value was 100. The mean value of the students' knowledge about hepatitis A after counseling in MTsN 02 Bondowoso 2015 was 93.21 with the lowest value waf 62.5 and the highest value was 100. Paired t test showed that t (-9.07) > t table (1.98), the null hypothesis (H0) was rejected. There was a difference between students' knowledge about hepatitis A before and after counseling in MTsN 02 Bondowoso 2015. This study showed that routine counseling by healthcare provider was important to prevent hepatitis A infection.; Keywords: counseling, knowledge of students, hepatitis


1974 ◽  
Vol 75 (2) ◽  
pp. 274-285 ◽  
Author(s):  
A. Gordin ◽  
P. Saarinen ◽  
R. Pelkonen ◽  
B.-A. Lamberg

ABSTRACT Serum thyrotrophin (TSH) was determined by the double-antibody radioimmunoassay in 58 patients with primary hypothyroidism and was found to be elevated in all but 2 patients, one of whom had overt and one clinically borderline hypothyroidism. Six (29%) out of 21 subjects with symptomless autoimmune thyroiditis (SAT) had an elevated serum TSH level. There was little correlation between the severity of the disease and the serum TSH values in individual cases. However, the mean serum TSH value in overt hypothyroidism (93.4 μU/ml) was significantly higher than the mean value both in clinically borderline hypothyroidism (34.4 μU/ml) and in SAT (8.8 μU/ml). The response to the thyrotrophin-releasing hormone (TRH) was increased in all 39 patients with overt or borderline hypothyroidism and in 9 (43 %) of the 21 subjects with SAT. The individual TRH response in these two groups showed a marked overlap, but the mean response was significantly higher in overt (149.5 μU/ml) or clinically borderline hypothyroidism (99.9 μU/ml) than in SAT (35.3 μU/ml). Thus a normal basal TSH level in connection with a normal response to TRH excludes primary hypothyroidism, but nevertheless not all patients with elevated TSH values or increased responses to TRH are clinically hypothyroid.


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