Continuous registration of thrombin generation in plasma:Its use for the determination of the thrombin potential

A method is described by which the time-course of thrombin generation in plasma can be obtained from a continuous optical density recording of p-nitroaniline (pNA) production in a 2:3 diluted plasma. A chromogenic substrate, methylmalonyl-methylanalyl-arginyl-pNA (SQ 68), is used that is specifically split by thrombin but at a low rate. The thrombin that appears and disappears in the plasma does not split more than 5% of the substrate added, so the rate of substrate conversion is in good approximation proportional to the amidolytic activity in the plasma over the entire period of thrombin generation. The course of the enzyme concentration can be calculated from the amidolytic activity curve. It is shown that the thrombin generation curves obtained in this way are essentially identical to those obtained via the classical subsampling method.The presence of SO 68 influences the amount of free thrombin that appears in plasma because it competitively inhibits the inactivation of thrombin by AT III and alpha2 macroglobulin. The inhibition of the thrombin peak by heparin, relative to an uninhibited control, remains unaltered by the presence of the substrate.From the course of thrombin activity and the prevailing decay constants, the course of prothrombin conversion velocity can be calculated. Prothrombin conversion was seen to be inhibited at high (>500 muM) substrate concentrations only, and experimental conditions are found under which the inhibition of the clotting process by the substrate is negligible.The amidolytic activity is the sum of the activities of free thrombin and of the alpha2 macroglobulin-thrombin complex formed. Via a mathematical procedure the amount of SQ 68 that has been split by thrombin alone and not by the alpha2 macroglobulin-thrombin complex, can be derived from the course of the optical density.The total amount of SQ 68 eventually split by thrombin alone is proportional to the surface under the thrombin generation curve, i. e. to the time-integral of free thrombin. This value, that we call the thrombin potential (TP), directly indicates how much of any physiological substrate can potentially be split by the thrombin being generated in the plasma

A comparison of visual working memory and episodic memory performance in younger and older adults

Item does not contain fulltextWorking memory and episodic memory decline with age.  However, as they are typically studied separately, it is largely unknown whether age-associated differences are similar. A task design was developed in which visual working memory and episodic memory performances were measured using the same stimuli, with both tasks involving context binding. A 2-back working memory task was followed by a surprise subsequent recognition memory task that assessed incidental encoding of object locations of the 2-back task. The study compared performance of younger (N=30; Mage=23.5, SDage=2.9, range=20-29) and older adults (N=29; Mage=72.1, SDage=6.8, range=62-90). Older adults performed worse than younger adults, without an interaction effect. In younger, but not in older adults, performance on the two tasks was related. We conclude that although age differences (Young>Older) are similar in the working memory and incidental associative memory tasks, the relationship between the two memory systems differs as a function of age group.20 p

Solar cell

A solar cell comprising a semiconductor layer (1), a collecting layer (6) for collecting free charge carriers from the semiconductor layer (1) and a buffer layer (3) which is arranged between the semiconductor layer (1) and the collecting layer (6), which buffer layer (3) is designed as a tunnel contact (31) between the semiconductor layer (1) and the collecting layer (6) is characterised in that the buffer layer (3) essentially comprises a material with a surface charge density of at least 1012 cm-2, preferably of at least 5x1012 cm- 2

Mindwandering propensity modulates episodic memory consolidation

Research into strategies that can combat episodic memory decline in healthy older adults has gained widespread attention over the years. Evidence suggests that a short period of rest immediately after learning can enhance memory consolidation, as compared to engaging in cognitive tasks. However, a recent study in younger adults has shown that post-encoding engagement in a working memory task leads to the same degree of memory consolidation as from post-encoding rest. Here, we tested whether this finding can be extended to older adults. Using a delayed recognition test, we compared the memory consolidation of word–picture pairs learned prior to 9 min of rest or a 2-Back working memory task, and examined its relationship with executive functioning and mindwandering propensity. Our results show that (1) similar to younger adults, memory for the word–picture associations did not differ when encoding was followed by post-encoding rest or 2-Back task and (2) older adults with higher mindwandering propensity retained more word–picture associations encoded prior to rest relative to those encoded prior to the 2-Back task, whereas participants with lower mindwandering propensity had better memory performance for the pairs encoded prior to the 2-Back task. Overall, our results indicate that the degree of episodic memory consolidation during both active and passive post-encoding periods depends on individual mindwandering tendency

DEGREES OF COMPETITION, THE RATE OF RETURN AND GROWTH FROM A CLASSICAL/SRAFFIAN PERSPECTIVE

The purpose of the paper is a clarification of the concept of competition from a classical/ Sraffian perspective; including an elucidation of how a classical/Sraffian approach might go about defining the degree of competition. This in turn allows for a sharper contrast between the Sraffian view of competition and mainstream views. The starting point for the analysis is the work of Clifton which interprets the classical/Sraffian view of competition as more general than that of orthodoxy: one which can encompass competition between production units in a given industry as something constrained by more dominant forms of competition such as that between production units across industries for shares of the corporate surplus. Following on from the work of both Clifton and Semmler, and starting from the assumption that multi-divisional corporation is the relevant “firm”, and that the corporate target rate of return is the relevant rate of profit, the question arises as to what determines the latter. And this question has received very little attention outside the more traditional post-Keynesian literature on pricing. The paper explores what is probably the most serious attempt within this literature - in the work of Eichner - to explain the target rate, in terms the desired growth rate of the corporation. This proposition has some interesting implications for a Sraffian approach, not least because it allows a link running from the expected growth of the economy to the target rate and thus the rate of profit. This in turn requires a discussion of the consistency of such a link with the Sraffian critique of the Cambridge growth equation. As well, a link between the target rate of return and the desired corporate growth rate link also has implications for the mechanics by which sectoral profit rates converge and thus for the classical/Sraffian literature on cross-dual dynamics

The mating biology of social insects

Many individuals who sustain moderate-severe traumatic brain injuries (TBI) are poor at recognizing emotional expressions, with a greater impairment in recognizing negative (e.g., fear, disgust, sadness, and anger) than positive emotions (e.g., happiness and surprise). It has been questioned whether this "valence effect" might be an artifact of the wide use of static facial emotion stimuli (usually full-blown expressions) which differ in difficulty rather than a real consequence of brain impairment. This study aimed to investigate the valence effect in TBI, while examining emotion recognition across different intensities (low, medium, and high). METHOD: Twenty-seven individuals with TBI and 28 matched control participants were tested on the Emotion Recognition Task (ERT). The TBI group was more impaired in overall emotion recognition, and less accurate recognizing negative emotions. However, examining the performance across the different intensities indicated that this difference was driven by some emotions (e.g., happiness) being much easier to recognize than others (e.g., fear and surprise). Our findings indicate that individuals with TBI have an overall deficit in facial emotion recognition, and that both people with TBI and control participants found some emotions more difficult than others. These results suggest that conventional measures of facial affect recognition that do not examine variance in the difficulty of emotions may produce erroneous conclusions about differential impairment. They also cast doubt on the notion that dissociable neural pathways underlie the recognition of positive and negative emotions, which are differentially affected by TBI and potentially other neurological or psychiatric disorders. (JINS, 2014, 20, 1-10)

Process competences to incorporate in higher education curricula

This study reports on a survey on project managers' priorities. The survey used ISO 21500 as a scaffold to ask various respondents, like junior, experienced, and senior project managers, project sponsors, and students, to share their perceptions on the priorities for junior project managers. The respondent groups shared similar perceptions. Furthermore, project type and sector had little effect on junior project managers' priorities. Experienced and senior project managers shared their own priorities as well. The perceptions of priorities for junior, experienced, and senior project managers were mostly alike. However, experienced and senior project managers' priorities seemed slightly more affected by project type and sector. A session with experts in project management and teaching project management highlighted that the results for junior project managers could provide accents for introducing project management to students in higher education, provided the entire playing field of project management is also introduced.</p