The challenge of science at the outset of the third millenium

Compared to others species Homo sapiens is physically underprivileged as much by his relative weakness than by his lack of natural defense. Only his mental abilities allowed him to cope with the various dangers which threaten him and to rule over the biosphere that he managed to modified for his own benefit. The neolithic revolution which saw the generalization of agriculture and the breeding of animals offered a considerable quantities of resources which lead to a strong demographic growth. All this produced a successions of discoveries which improved his quality of life. Today after an era of quantitative growth the production of the agroalimentary sector enter a qualitative period in which the aim is note only to increase the production of the traditional resources but, by the alteration of the genetic heritage, to improve their properties.     

Self-organization of genetic coding

The self-organization of genetic coding is studied in a simple model system which uses the products of translation as catalysts for the process. The system studied contains protein molecules chosen from a sequence space of high dimension. Catalysts which assign amino acids to codons are chosen in such a way that a random selection of proteins synthesizes further proteins randomly. Under some circumstances, dictated by the genetic information supplied to the system and the manner in which protein function depends on protein sequence, the state of random synthesis is unstable. The system then evolves spontaneously to a new state in which proteins synthesize further proteins in an ordered fashion, typically executing the rules of a simple code for the assignment of amino acids to codons. For some embeddings of protein functions in the protein sequence space, the domains of stability of the ordered and disordered states are calculated. Computer simulation verify that coding self-organization occurs in a variety of systems of the sort studied. Coding self-organization among catalysts which recognize genetic information is a high order co-operative selection process which provides the link between genotype and phenotype needed for the Darwinian evolution of complex biochemical systems.     

Characterization of proteolytic activities of rumen bacterial isolates from forage-fed cattle

The proteolytic activities of eight strains of ruminal bacteria isolated from New Zealand cattle were characterized with respect to their cellular location, response to proteinase inhibitors and hydrolysis of artificial proteinase substrates. The Streptococcus bovis strains had predominantly cell-bound activity, which included a mixture of serine and cysteine-type proteinases which had high activity against leucine p-nitroanilide (LPNA). The Eubacterium strains had a mainly cell-associated activity with serine and metallo-type proteinases which showed high activity against the chymotrypsin substrate, N-succinyl alanine alanine phenylalanine proline p-nitroanilide (NSAAPPPNA) and some LPNA activity. A Butyrivibrio strain, C211, had a cell-bound mixture of cysteine and metallo-proteinase activities and strongly hydrolysed NSAAPPPNA and LPNA while the high activity Butyrivibrio-like strain, B316, had a cell-bound, mainly serine proteinase activity which strongly hydrolysed NSAAPPPNA. A Prevotella-like strain, C21a, had a mixture of cysteine, serine and metallo-proteinase activities which were cell-bound and hydrolysed LPNA. The activities of these strains did not match those of the bacterial fraction of rumen fluid, which contained activities mainly of the cysteine type with specificity towards the substrate N-succinyl phenylalanine p-nitroanilide. The contribution of these strains to proteolysis in the rumen is discussed.     

Confounding of sources of variation in factor-analytic techniques.

Illustrates a statistical model which is a 2-way analysis of variance model which requires that factor-analytic techniques be used to decompose the interaction parameters. Factor-analytic techniques are commonly applied directly to matrices which contain a grand mean and/or row and/or column effects in addition to row * column interaction. Each factor obtained from such an analysis will generally account for variation due to all sources of variation present in the initial matrix. Some ways in which such confounding of sources of variation causes difficulties in making valid interpretations of factors are discussed. Special attention is given to the problem of describing individual differences in patterns of performance on a set of measurements. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of motivations on the availability and retrieval of memory traces.

A review which analyzes a vast array of studies relating motivation and memory is presented. Investigations in which the motivational manipulation occurred during trace formation are distinguished from studies in which the manipulation occurred during trace storage or trace retrieval. Includes a series of investigations by the author which varied the incentive for retaining stimuli. The general conclusion is that many studies in the area are methodologically inadequate, and have yielded conflicting results. However, there are studies which provide strong evidence that memory can be influenced by nonassociative factors. (3 p. ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Criteria for selecting the components of composites

Composites combine the properties of two or more components. Conceptual tools are developed which guide the selection of components for making composites which maximise one or more aspect of thermo-mechanical performance. There are three key ideas: (a) the use of performance or “merit” indices to describe material performance; (b) the construction of material-property charts onto which the performance indices can be ploteed and (c) the use of bounds to define on the charts the envelope of properties which a given composite system could, potentially, fill. The method reveals in a simple way the promise or lack of promise of a given composite system, and suggests novel combinations which, if they can be fabricated, should perform well.     

Differentiation of B cells in the nonlymphoid tissue of the synovial membrane of patients with rheumatoid arthritis

In patients with rheumatoid arthritis the synovial membrane of the affected joint is infiltrated with lymphoid cells which may be arranged in structures resembling germinal centers. We have directly isolated such infiltrates to determine whether B-cell clones within them are selected and expanded in a process analogous to that which normally takes place in the germinal centers in secondary lymphoid organs. The data suggest that an antigen-driven process leads to the accumulation of B cells in the synovial membrane. The finding of identical sequences in consecutive sections suggests that under conditions of chronic stimulation, memory B cells may enter a stage of differentiation in which they proliferate without further accumulation of somatic mutations. Further we see intraclonal diversity which underlines the germinal center-like character of these infiltrates and demonstrates that a microenvironment is built up in this nonlymphoid tissue which supports antigen-dependent differentiation of B cells. This is the first demonstration, to our knowledge, of a germinal center-like reaction outside lymphoid tissue.     

The evaluation of instrument displays: A point of view.

"One of the most common duties to fall to an applied experimental psychologist is evaluation… . The control of a machine by a man may be conceived as a process of information exchange between man and machine… . Since it is the function of an instrument display in a man-machine system to present the human operator with signs, and since the signs may have the functions of command, designation, and computation, any evaluation of a display must be in terms of its success in presenting signs which perform these functions… . The properties of an instrument display in virtue of which its indications are effective in command and designation are the properties which must be assessed in an evaluation of the display." The point of view presented rests on 6 major principles which are stated, and the point of view is summarized in the statement that: "the only research which can in any significant measure lead to applied decisions is research of general import." (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interpretation of persuasive messages as a function of prior immunization.

2 experiments were conducted in which passive immunization was achieved by providing Ss with counterarguments against presuasive messages to which they were later exposed. In both studies, this procedure produced a significant tendency to displace the perceived content of the "change" message toward the stand advocated in the immunization message. These results were tentatively attributed to the Ss' attempts to minimize the discrepancy between the opposing statements, both of which appeared to emanate from prestigeful sources. Judgments were not affected by active immunization, a procedure in which Ss attempted to refute (in writing) weakened versions of the change message to which they were later exposed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fine structure of postgonopodial glands of a myriapod Glomeris marginata (Villers)

The postgonopodial gland of the myriapod Glomeris marginata (Villers), which produces a pheromone, is an integumentary gland comprising numerous functional secretory units. Each secretory unit consists of two proximal secretory cells, an intermediary cells lacking secretory characteristics and a canal cell surrounding the canal, which is secretory in nature. Secretory proximal cells exhibit a zone of small channels originating from invaginations of the plasma membrane and through which secreted material is released. Apposing each invagination of these cells is a corresponding invagination of the intermediary cell: the two units in the centre of the intermediary cell join another which communicates with the canal. Secretion produced by the latter passes through the canal wall and bends with secretion of the two proximal cells. The most striking feature of all these cells is the abundance of tubules and fibrils in the small canal zone in the proximal cells, which also exhibits a centriole; in the intermediary cell around cytoplasmic membrane invaginations where a diplosome is present, and in almost the entire canal cell.     

Some effects of verbal expression of hostility.

113 Ss participated in simulated interaction in the course of which they were verbally attacked. The experiment demonstrated (with a Before-After measure) increased hostility in the Ss at the end of the experiment which was a positive function of the number of hostile statements made to the attacker after the attack. A vicarious analogue was consistent in showing a similar increase. The major findings are inconsistent with a simple catharsis hypothesis. They are more easily interpreted by viewing hostility as instrumental behavior which is unsuccessful (frustrated) and as a result increases in intensity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A Method of Predicting the Elastic Characteristics of Diamond Composites

A model is considered for a representative cell, which is based on structural research on a particular composite, which consists of relatively large diamond single crystals in a relatively fine-grained SiC matrix; the elastic constants are calculated from an asymptotic averaging method.     

A theory of equilibrium in token economics.

Presents a theory which predicts that performance will stabilize at an equilibrium level in a long-term token economy. This prediction is based on the joint consideration of consumption schedules (relationships between income and expenditure) and a hypothesized critical range of savings (a range of savings above which performance deteriorates and below which performance improves). Procedures derived from these 2 concepts which break this equilibrium and promote therapeutic progress are described. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Geometry of grain boundaries

The first part of this paper deals with the problem of describing and measuring microstructure in exact terms. The Euclidean parameters: volume, area, length, and angle can be measured and expressed only in terms of the total of each in unit volume. Average properties, such as average grain diameter, are accessible only through the topological parameters, specifically number in unit volume, which can be measured only by serial sectioning. The parameters which have been used to represent the concept of grain size are analyzed and shown in most cases to represent a function of grain boundary area. In a second section of this paper the geometric problem of plastic slip through a grain boundary is analyzed. A method is proposed by which all of the components of the deformation, as well as the crystallographic directions, can be manipulated simultaneously through the use of a stereographic projection. The third section of this paper is concerned with the geometry of grain growth. The polycrystalline state is described as a grain boundary network, which must respond to the requirements of surface tension. The several topological changes in a network which can contribute to grain growth are described.     

Preliminary report of data collection in hospital quality assurance programs--a project of the Association of Hospitals of the Czech Republic

OBJECTIVES: This was the first attempt of the association representing all acute care hospitals in the Czech Republic to collect mutual data which might be used for quality assurance (QA) purposes and which might lead to the development of national standards of care which could be used for hospital accreditation. Data collected included information which was available universally and which could be measured; in addition, information was intended to be similar in each hospital. In most cases, the data collection systems were based on financial information and data had to be identified which might be used for QA purposes, rather than being able to design a system specific for QA purposes. DESIGN: Since the hospital payment system was established in 1992, hospitals have had to develop data collection systems to measure clinical activity; this current study was based on this data collection, adapted to QA purposes. SETTING: The Executive Committee of the Hospital Association agreed to a pilot study of hospitals in 1993; data were collected from approximately 40 hospitals, beginning in 1994. STUDY PARTICIPANTS: Hospitals were chosen based on their ability to collect data and participate in the program, and it was determined that there should be variability in the hospitals, in size, location and activities, but that the data collected should be generic. INTERVENTIONS: Raw data included 33 different items, most of which were irrelevant to QA. Using a computer program, various combinations of data were reviewed and evaluated to ascertain the most appropriate for QA purposes. MAIN OUTCOME MEASURES: Data were chosen for study which included (a) data from the largest departments in the individual hospitals; (b) length of stay for patients hospitalized in these departments; (c) number of occupied beds/physician in the department and (d) mortality/1000 admissions to the department. RESULTS: The combination of (1) a long length of stay; (2) a high occupied bed/doctor ratio; and (3) a high mortality rate/1000 admissions might be indicators of poor quality. Additional factors to consider include: the type of department-emergency, cancer, geriatric, etc.; the nature of the medical activity-acute, referral, primary care, etc.; whether or not "social" beds are included and, generally, comparability among departments. However, as a pilot study, certain indicators can be determined which then can be used for future study to determine quality of care. The ability to cooperate and collect seemingly comparable data indicates reason for optimism in the future; more detailed and accurate studies can be carried out which will enable assessment of the quality of care given in comparable situations in hospitals throughout the Czech Republic.     

Structure of the attachment of the vocal ligament to the perichondrium of the thyroid cartilage

The ventral attachement of the ligamentum vocale of eleven larynges (new-born and adults has been studied in sagittal, frontal and horizontal sections. 1. Supplementary to the known structure of the ventral attachement of the ligamentum vocale we have noticed collagen fibers which ascend in the inner angle of the thyroid cartilage and which partly cross to the other side. Sometimes a few fibers which are running downward have been observed. This structure of the attachement must be more firm than the known structure. 2. Moreover it has been observed that a lot of the angles of the crossing collagen fibers in the cartilage of the lamina mediana (near the attachement of the ligamentum vocale) are right-angled, whereas the angles of the fibers which lie in the laminae laterales in their majority are acute-angled. This phenomenon also is interpreted as a structure which makes the lamina mediana firmer. The fact, that this structure is not so evident in the specimens of the new-born as in those of the adults indicates that there are postnatal changes in the structure of the lamina mediana.     

An unusual case of cystic chondroblastoma of the patella

An unusual case of chondroblastoma of the patella is presented in which the dominant feature was a hemorrhagic cyst. The chondroblastoma was located in a small gritty mass at one pole of the cyst, which could have easily been overlooked.     

The neurotropic variant of desmoplastic spindle cell melanoma of the foot--a report of two cases with special reference to its schwanian features

Melanomas are known to show a wide range of morphological expression. Desmoplastic Malignant Melanoma (DMM) which is a variant of spindle cell melanoma, is often characterised by conspicuous growth in and around nerves which leads to a mistaken diagnosis of malignant Peripheral Nerve Sheath tumours (MPNST). We report two such cases of spindle celled DMM of the foot which displayed neurotropism. The problems and the clinical relevance of distinguishing this variant of melanoma from MPNST is discussed.     

Chondrosarcomas of the skull base: review of the literature and report of two cases

The use of intravital microscopy as a tool for studying the microcirculation has increased greatly over the last several decades. Early microscopes provided the first pictures of the microcirculation, but were cumbersome to use and subjected the tissue to a high light intensity, a problem which has recently become the subject of much discussion. The goal of this project was therefore to build a more ergodynamic microscope which minimizes the light exposure to the tissue. The automation of the microscope controls provides a platform on which other options can be built into the microscope, such as an autofocus feature. Furthermore, the use of the Optimas software also opens the possibility for on-line data processing.