A Contribution to the Problem of Perceptual Constancy

The problem of the psychological nature of perceptual constancy is, as we know, among the most pressing and as yet unresolved problems of modern psychology. Despite the fact that the past decade has seen large-scale experimental investigation of the problem, the study of the psychological mechanism of this phenomenon has hardly gone beyond the advancement of a number of theories hypothetical in nature.     

A Contribution to the Problem of Systematized Delusions in Adolescents

As we know, rigorously systematized delusions of long duration are very rarely seen in children and adolescents. Sander (1) held that "original paranoia" may begin in early childhood. Krafft-Ebing (2) believed that "hereditary primary insanity," as distinguished from its late form, is encountered only in predisposed children— weak-willed, hypochondriac, pathologically quick to take offense — and is manifested in delusions of grandeur and ideas of reference and of special significance. G. E. Sukhareva, (3) describing systematized delusions in schizophrenic adolescents, expresses the opinion that within the framework of schizophrenia, such delusions occur primarily in psychopathic adolescents with schizoid traits: dominating, suspicious and inclined to fantasy. Stable delusions and delusive ideas against the background of a schizophrenic process in adolescents have also been described by certain other authors. (4-8)     

Perceptual Processes and the Maintenance of Polymorphism Through Frequency-dependent Predation

One of the key challenges of both ecology and evolutionary biology is to understand the mechanisms that maintain diversity. Negative frequency-dependent selection is a powerful mechanism for maintaining variation in the population as well as species diversity in the community. There are a number of studies showing that this type of selection, where individuals of a rare type (i.e. a rare morph or a rare species) experience higher survival than those of more common type(s). However, it is still not clear how frequency-dependent selection operates. Search image formation has been invoked as a possible, proximate explanation. Although the conceptual link between search image and frequency-dependent predation is often assumed in ecological and evolutionary studies, a review of the literature reveals a paucity of evidence demonstrating the occurrence of both in a natural predator-prey system. Advances in the field of psychology strongly support the existence of search image, yet these findings are not fully recognized in the realm of ecology and evolutionary biology, in part, we feel because of confusion and inconsistencies in terminology. Here we try to simplify the language, clarify the advances in the study of frequency-dependent predation and search image, and suggest avenues for future research. We feel that the investigations of both proximate (perceptual mechanisms) and ultimate (pattern of predation) processes are necessary to fully understand the importance of individual behavioural processes for mediating evolutionary and ecological diversity.Co-ordinating editor: O. Leimar     

Quantitative Approach to Determining the Contribution of Viable-but-Nonculturable Subpopulations to Malolactic Fermentation Processes

Different sizes of viable-but-nonculturable cell subpopulations of a lactic acid bacterium strain were induced by adding increasing amounts of SO₂. The experimental data obtained here were fitted to a segregated kinetic model developed previously. This procedure allowed us to determine in quantitative terms the contribution of this physiological state to malolactic fermentation.The persistence of stressed, damaged, or viable-but-nonculturable (VBNC) cells during microbial fermentation underlines the requirement of alternative methods for detecting and characterizing these emergent states not otherwise detectable by traditional culture-based methods (13). Flow cytometry (FC) has evolved as an outstanding tool in bioprocesses due to its usefulness in cell physiology monitoring (5, 12). The persistence of nonculturable cells during microbial fermentation has been attributed to changes in water activity, acidity, redox potential, nutrient availability, and starvation (14, 17, 18, 24, 25) or to the use of preserved starter cultures (20). Additionally, the quantification of catalytic activity is critical to bioprocess optimization, as it measures the individual contributions of different cell subpopulations to the global process (2, 13). Despite the loss of culturability under standard conditions, it is strongly suspected that VBNC cells remain alive, maintain the transport system and biosynthesis, and are able to metabolize substrates (16, 26). Gene expression has also been demonstrated previously (9, 23). However, although the physiology, biochemistry, and genetics of the VBNC state have been studied over the years, its functionality and biological implication are still issues under intense debate (1, 21, 22).In this work, cider malolactic fermentation (MLF) was selected as a model system to clarify the role played by VBNC cells in bioprocesses. MLF was carried out under different SO₂ concentrations (0, 30, and 60 ppm total) for inducing VBNC states. The fermentation medium was sterile apple must or “green” cider (obtained just after alcoholic fermentation and containing 5.6% [vol/vol] ethanol), obtained as previously described (11). Sodium bisulfite was used for SO₂ treatments. MLF was carried out in duplicate at 22°C statically in 250-ml bottles. An indigenous strain of Lactobacillus hilgardii was inoculated at an optical density at 600 nm of ∼0.1 to start MLF. Flasks were shaken just before sampling in order to homogenize the biomass content. Samples were taken aseptically at time intervals until malic acid was consumed (≤0.5 g liter⁻¹), and cells were collected and processed for further analysis as described previously (20). Supernatants were filtered (0.45 μm pore size) and frozen (−20°C) until chemical analysis. The amount of malic acid was determined by high-pressure liquid chromatography (Alliance 2690; Waters) with a photodiode array detector (Waters 996), as reported previously (19).     

The Role of Perceptual and Structural Similarity in Cross-adaptation

Cross-adaptation, the decrease in sensitivity to one odorantfollowing exposure to a different odorant, is affected by odorantsimilarity, both perceptual and structural, but the preciserelationship is obscure. The present series of studies was designedto explore various aspects of perceptual and structural similarityas they relate to cross-adaptation. In Experiment 1, cross-adaptationwas assessed between androstenone and five odorants that sharea common urinous note with androstenone, but retain unique perceptualcharacteristics; only the compound judged most perceptuallysimilar to androstenone cross-adapted it. In Experiment 2, odorantsboth perceptually and structurally similar (androstenone andandrostanone) displayed significant, mutual cross-adaptation.Furthermore, magnitude estimates for androstanone were significantlyreduced following exposure to 3-methylidene-5a-androstane (3M5A),a structurally similar, perceptually odorless compound. Thisfinding appears to be the first demonstration that an odorlesscompound can affect, via cross-adaptation, the perception ofan odorous compound. Finally, in Experiment 3, significant,asymmetric cross-adaptation was observed between compounds thatare perceptually and structurally dissimilar (4-cyclohexylcyclohexanone[4-CHCH] and androstenone). These findings indicate that therole of similarity in cross-adaptation is difficult to quantifyand emphasize the numerous odorant characteristics that canaffect cross-adaptation. Chem. Senses 21: 223–237, 1996.     

The Development of the Sauropsid Integument: A Contribution to the Problem of the Origin and Evolution of Feathers

Developmental anatomical data are insufficient to discuss plausibleintermediates between an ancestral, scaled, reptilian skin andappendage-bearing, avian skin. We also review adult tissue replacementand ubiquitous mechanisms underlying skin morphogenesis. Combiningdevelopmental data sensu lato with consideration of necessarybiological roles permits evaluation of major form/function trendsin skin evolution. New data on feathers reveal retention ofthe sauropsid synapomorphy of vertical alteration of - and ß-keratogenesis.By identifying roles that were obligatorily maintained throughoutevolution, we demonstrate constraints on hypothetical skin morphologiesin preavian taxa. We analyze feather origins as a problem ofemergence of complex form via modulations of morphogenesis.While existing data do not permit presentation of sequential,hypothetical, intermediates culminating in a plumage, the analysis:(1) implies that a protofeather and its follicle are most easilyderived from isolated, flattened, elongate, reptilian scales;(2) explains diversification of feather morphs from a contour-like"basic" feather and the similarity between feather and hairfollicles; and thus (3) reveals several developmental constraintson structures proposed as antecedent to avian feathers, whetherhypothetical constructs or palaeontological interpretations.Although these conclusions do not depend on any previous scenario,they are consistent with Regal's (1975) model and the limited,fossil evidence, especially that of the "basal archosaur" Longisquama.     

Plasmolipin and Its Role in Cell Processes

Molecular Biology - The mechanisms involved in the origin and development of malignant and neurodegenerative diseases are an important area of modern biomedicine. A crucial task is to identify new...     

The Role of Hydrodynamic Processes on Anchovy Eggs and Larvae Distribution in the Sicily Channel (Mediterranean Sea): A Case Study for the 2004 Data Set

Knowledge of the link between ocean hydrodynamics and distribution of small pelagic fish species is fundamental for the sustainable management of fishery resources. Both commercial and scientific communities are indeed seeking to provide services that could “connect the dots” among in situ and remote observations, numerical ocean modelling, and fisheries. In the Mediterranean Sea and, in particular, in the Sicily Channel the reproductive strategy of the European Anchovy (Engraulis encrasicolus) is strongly influenced by the oceanographic patterns, which are often visible in sea surface temperature satellite data. Based on these experimental evidences, we propose here a more general approach where the role of ocean currents, wind effects, and mesoscale activity are tied together. To investigate how these features affect anchovy larvae distribution, we pair ichthyoplankton observations to a wide remote sensing data set, and to Lagrangian numerical simulations for larval transport. Our analysis shows that while the wind-induced coastal current is able to transport anchovy larvae from spawning areas to the recruiting area off the Sicilian south-eastern tip, significant cross-shore transport due to the combination of strong northwesterly mistral winds and topographic effects delivers larvae away from the coastal conveyor belt. We then use a potential vorticity approach to describe the occurrence of larvae cross-shore transport. We conclude that monitoring and quantifying the upwelling on the southern Sicilian coast during the spawning season allows to estimate the cross-shore transport of larvae and the consequent decrease of individuals within the recruiting area.     

Glasgow Medical Women 1951-4: Their Contribution and Attitude to Medical Work

A questionary sent to 137 women who qualified in Glasgow during 1951–4 showed that of the 106 respondents 24% of the married women were unemployed and only 31% were working full-time. The married women had fewer qualifications than a matched group of male contemporaries, and fewer of those in hospital work were consultants. The married women in full-time work had fewer children and showed some differences in their background compared with those working part-time or unemployed. Most part-time workers were satisfied with their present posts and did not wish to work more.     

A Contribution to the Problem of Anorexia Nervosa (with Respect to One of the Causes of Secondary Anorexia)

Anorexia — refusal of food for various reasons — is not only a psychiatric problem, but also interests therapeutists, endocrinologists and pediatricians. The definition, "nervous anorexia" substantially narrows this affection to a rather distinctive clinical picture, in which young women (considerably less often, young men) are described who stubbornly refuse to eat, and not infrequently reach a stage of pronounced cachexia.     

The Problem of the Unconscious in the Psychological Concept of Set

In the pages of the three-volume anthology The unconscious: Its nature, function, and methods of investigation (Tbilisi, 1978), the following incorrect positions are presented concerning the relationship between the concept of set and the problem of the unconscious: (1) the unconscious is real only as a form of existence of physiological processes; (2) the unconscious is a category whose use is incompatible with dialectical materialist methodology in psychology; and (3) the identity of the concept of set (in D. N. Uznadze's conception) with the psychological concept of the unconscious makes the concept of set superfluous for psychology as an explanatory science (see [3. Vol. 1, p. 74]). Let us examine some aspects of these postulates.     

Role of Glycine in Blood Coagulation Processes

We studied hemocoagulant properties of the amino acid glycinein vitroand after intravenous administration to animals (rats). Addition of 10^–3and 10^–4M glycine to the plasma increases the aggregability of thrombocytesin vitro, while all other test concentrations had virtually no effect on hemostatic parameters of the plasma. Intravenous administration of glycine increased the functional activity of the enzymatic fibrinolytic unit of the anticoagulation system. Dose dependence of this effect has been established. The causes of these changes and possible application of glycine as an agent activating fibrinolysis are discussed.     

Vanadium in Biosphere and Its Role in Biological Processes

Ultra-trace elements or occasionally beneficial elements (OBE) are the new categories of minerals including vanadium (V). The importance of V is attributed due to its multifaceted biological roles, i.e., glucose and lipid metabolism as an insulin-mimetic, antilipemic and a potent stress alleviating agent in diabetes when vanadium is administered at lower doses. It competes with iron for transferrin (binding site for transportation) and with lactoferrin as it is secreted in milk also. The intracellular enzyme protein tyrosine phosphatase, causing the dephosphorylation at beta subunit of the insulin receptor, is inhibited by vanadium, thus facilitating the uptake of glucose inside the cell but only in the presence of insulin. Vanadium could be useful as a potential immune-stimulating agent and also as an antiinflammatory therapeutic metallodrug targeting various diseases. Physiological state and dose of vanadium compounds hold importance in causing toxicity also. Research has been carried out mostly on laboratory animals but evidence for vanadium importance as a therapeutic agent are available in humans and large animals also. This review examines the potential biochemical and molecular role, possible kinetics and distribution, essentiality, immunity, and toxicity-related study of vanadium in a biological system.     

A Contribution to the Determination of Polychlorobenzenes in Sediments

A full analytical procedure involving extraction and clean-up is presented for the determination of the tri-, tetra-, penta- and hexa-chlorobenzenes in sediments. For this study, the gas chromatography coupled to electronic capture detection was used.

The samples were dried with sodium sulphate and Soxhlet extracted for 16 hours with dichloromethane. Then this solvent was replaced by hexane and the resulting solution was concentrated in a rotary evaporator. The clean-up process consisted of elution through a mixed silica column followed by a treatment with activated copper turnings to remove the sulphur. The sample was then concentrated down to 2 mL by nitrogen stream. The internal standard, 1,4-dibromobenzene, was added to the sample prior to the extraction, whereas the injection standard, 1,3,5-tribromobenzene, was added right before the sample was injected through the chromatographic system.

The limits of quantification ranged from 71 to 500 pg g^?1 (dry weight). The reproducibility in the peak areas within a day was better for the compounds with increasing number of chlorines, whereas the reproducibility over time studies provided no significant differences in the peak areas in consecutive days.

The method was successfully applied to the determination of polychlorobenzenes in a certified sediment and, finally, it was applied to the determination of these compounds in several sections of a sediment core from Esthwaite Water Lake (United Kingdom).