The conundrum of correlation and causation

2001 ◽  
Vol 24 (6) ◽  
pp. 1073-1074 ◽  
Author(s):  
Irene M. Pepperberg

Biology can inspire robotic simulations of behavior and thus advance robotics, but the validity of drawing conclusions about real behavior from robotic models is questionable. Robotic models, particularly of learning, do not account, for example, for (a) exaptation: co-opting of previously evolved functions for new behavior, (b) learning through observation, (c) complex biological reality, or (d) limits on computational capacity.

1965 ◽  
Vol 14 (03/04) ◽  
pp. 431-444 ◽  
Author(s):  
E. R Cole ◽  
J. L Koppel ◽  
J. H Olwin

SummarySince Ac-globulin (factor V) is involved in the formation of prothrombin activator, its ability to complex with phospholipids was studied. Purified bovine Ac-globulin was complexed to asolectin, there being presumably a fixed number of binding sites on the phospholipid micelle for Ac-globulin. In contrast to the requirement for calcium ions in the formation of complexes between asolectin and autoprothrombin C, calcium ions were not required for complex formation between asolectin and Ac-globulin to occur ; in fact, the presence of calcium prevented complex formation occurring, the degree of inhibition being dependent on the calcium concentration. By treating isolated, pre-formed aso- lectin-Ac-globulin complexes with calcium chloride solutions, Ac-globulin could be recovered in a much higher state of purity and essentially free of asolectin.Complete activators were formed by first preparing the asolectin-calcium- autoprothrombin C complex and then reacting the complex with Ac-globulin. A small amount of this product was very effective as an activator of purified prothrombin without further addition of calcium or any other cofactor. If the autoprothrombin C preparation used to prepare the complex was free of traces of prothrombin, the complete activator was stable for several hours at room temperature. Stable preparations of the complete activator were centrifuged, resulting in the sedimentation of most of the activity. Experimental evidence also indicated that activator activity was highest when autoprothrombin C and Ac-globulin were complexed to the same phospholipid micelle, rather than when the two clotting factors were complexed to separate micelles. These data suggested that the in vivo prothrombin activator may be a sedimentable complex composed of a thromboplastic enzyme, calcium, Ac-globulin and phospholipid.


Author(s):  
Milen Dimov

The present study traces the dynamics of personal characteristics in youth and the manifested neurotic symptoms in the training process. These facts are the reason for the low levels of school results in the context of the existing theoretical statements of the problem and the empirical research conducted among the trained teenagers. We suggest that the indicators of neurotic symptomatology in youth – aggression, anxiety, and neuroticism, are the most demonstrated, compared to the other studied indicators of neurotic symptomatology. Studies have proved that there is a difference in the act of neurotic symptoms when tested in different situations, both in terms of expression and content. At the beginning of the school year, neurotic symptoms, more demonstrated in some aspects of aggressiveness, while at the end of school year, psychotism is more demonstrated. The presented summarized results indicate that at the beginning of the school year, neurotic symptoms are strongly associated with aggression. There is a tendency towards a lower level of social responsiveness, both in the self-assessment of real behavior and in the ideal “I”-image of students in the last year of their studies. The neurotic symptomatology, more demonstrated due to specific conditions in the life of young people and in relation to the characteristics of age.


1951 ◽  
Vol 190 (1) ◽  
pp. 133-148
Author(s):  
Howard. Tint ◽  
Wilhelm. Reiss
Keyword(s):  

Agriculture ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 592
Author(s):  
Sugirbay Adilet ◽  
Jian Zhao ◽  
Nukeshev Sayakhat ◽  
Jun Chen ◽  
Zagainov Nikolay ◽  
...  

Investigating the interactions of granular fertilizers with various types of equipment is an essential part of agricultural research. A numerical technique simulating the mechanical behavior of granular assemblies has the advantage of data trackings, such as the trajectories, velocities, and transient forces of the particles at any stage of the test. The interaction parameters were calibrated to simulate responses of granular fertilizers in EDEM, a discrete element method (DEM) software. Without a proper calibration of the interaction parameters between the granular fertilizers and various materials, the simulations may not represent the real behavior of the granular fertilizers. Therefore, in this study, a strategy is presented to identify and select a set of DEM input parameters of granular fertilizers using the central composite design (CCD) to establish the nonlinear relationship between the dynamic macroscopic granular fertilizer properties and the DEM parameters. The determined interaction properties can be used to simulate granular fertilizers in EDEM.


2021 ◽  
Vol 17 (2) ◽  
pp. 1-25
Author(s):  
Dat Tran ◽  
Christof Teuscher

Emerging memcapacitive nanoscale devices have the potential to perform computations in new ways. In this article, we systematically study, to the best of our knowledge for the first time, the computational capacity of complex memcapacitive networks, which function as reservoirs in reservoir computing, one of the brain-inspired computing architectures. Memcapacitive networks are composed of memcapacitive devices randomly connected through nanowires. Previous studies have shown that both regular and random reservoirs provide sufficient dynamics to perform simple tasks. How do complex memcapacitive networks illustrate their computational capability, and what are the topological structures of memcapacitive networks that solve complex tasks with efficiency? Studies show that small-world power-law (SWPL) networks offer an ideal trade-off between the communication properties and the wiring cost of networks. In this study, we illustrate the computing nature of SWPL memcapacitive reservoirs by exploring the two essential properties: fading memory and linear separation through measurements of kernel quality. Compared to ideal reservoirs, nanowire memcapacitive reservoirs had a better dynamic response and improved their performance by 4.67% on three tasks: MNIST, Isolated Spoken Digits, and CIFAR-10. On the same three tasks, compared to memristive reservoirs, nanowire memcapacitive reservoirs achieved comparable performance with much less power, on average, about 99× , 17×, and 277×, respectively. Simulation results of the topological transformation of memcapacitive networks reveal that that topological structures of the memcapacitive SWPL reservoirs did not affect their performance but significantly contributed to the wiring cost and the power consumption of the systems. The minimum trade-off between the wiring cost and the power consumption occurred at different network settings of α and β : 4.5 and 0.61 for Biolek reservoirs, 2.7 and 1.0 for Mohamed reservoirs, and 3.0 and 1.0 for Najem reservoirs. The results of our research illustrate the computational capacity of complex memcapacitive networks as reservoirs in reservoir computing. Such memcapacitive networks with an SWPL topology are energy-efficient systems that are suitable for low-power applications such as mobile devices and the Internet of Things.


1992 ◽  
Vol 225 (1) ◽  
pp. 107-123 ◽  
Author(s):  
Francesco Frigerio ◽  
Alessandro Coda ◽  
Luisa Pugliese ◽  
Claudia Lionetti ◽  
Enea Menegatti ◽  
...  

1987 ◽  
Vol 104 ◽  
Author(s):  
S. Hahn ◽  
M. Arst ◽  
K. N. Ritz ◽  
S. Shatas ◽  
H. J. Stein ◽  
...  

ABSTRACTEffects of high carbon concentration upon oxygen precipitate formation in Cz silicon have been investigated by combining various furnace and rapid thermal annneals. Even though oxide precipitate density increases with increasing carbon levels, Cs, synchrotron radiation section topographs of processed high carbon content wafers (Cs ∼ 4ppma) exhibit Pendellosung fringes, indicating a strain free bulk state. Our optical microscopic data have also shown very few defect etch features inside the bulk. A model based upon a direct coupling of both SiO2 and Si-C complex formation reactions is used to explain rather unique oxygen precipitation characteristics in the high carbon content Cz Si materials.


2017 ◽  
Vol 07 (03) ◽  
pp. 1750020 ◽  
Author(s):  
Md Kashif Shamim ◽  
Seema Sharma ◽  
Sangeeta Sinha ◽  
Eqra Nasreen

We have investigated the structure, dielectric and electrical properties of lead-free polycrystalline (Na[Formula: see text] K[Formula: see text] Li[Formula: see text]) NbO3 ceramics as a function of temperature and frequency in order to understand the intrinsic contribution of grain/bulk and grain boundary effects toward the dielectric response as well as the electrical conduction mechanism in the samples fabricated by microwave sintering method. X-ray diffraction analysis exhibits perovskite structure with orthorhombic symmetry, which is well supported by the Raman spectroscopic analysis. A minor secondary impurity phase of tungsten bronze structure was observed for samples sintered at 1050[Formula: see text]C, which gets weaker for samples sintered at 1150[Formula: see text]C. Dielectric permittivity was enhanced by 50%, although there was a reduction in the dielectric loss by about 50% at Curie temperature (450[Formula: see text]C) for samples sintered at 1150[Formula: see text]C. Complex impedance spectroscopic analysis indicated non-Debye-type dielectric relaxation present in the samples, and this phenomenon followed thermally activated process related to hopping mechanism. Nyquist plot showed the negative temperature coefficient of resistance, characteristic of the samples.


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