Specific Scientific Questions Research Articles

Non-mammalian models for studying neural development and function.

Early neuroscientists scoured the animal kingdom for the ideal preparation with which to study specific problems of interest. Today, non-mammalian nervous systems continue to provide ideal platforms for the study of fundamental problems in neuroscience. Indeed, the peculiarities of body plan and nervous systems that have evolved to carry out precise tasks in unique ecological niches enable investigators not only to pose specific scientific questions, but also to uncover principles that are general to all nervous systems.

Hematopoietic stem cell transplantation for autoimmune diseases in Brazil: current status and future prospectives

In this paper, we discuss the launching of a cooperative protocol of hematopoietic stem cell transplantation for autoimmune diseases in Brazil. We present specific conditions of the country's health system which would affect the trial, preliminary results of the first nine patients transplanted under the protocol (4 systemic lupus, 3 multiple sclerosis, one systemic sclerosis and one overlapping lupus + systemic sclerosis) and future prospectives of organizing phase III randomized trials to answer specific scientific questions pending in the field.

Models are better than their theory

As modelling becomes a popular approach in the study of biological systems it is necessary to clarify its concepts and dimensions. This helps to characterize and to distinguish models but cannot establish their quality. The virtue of a model depends on the insight gained in respect to a specific scientific question, and it is hard to measure this with a theory.

Learning from biological systems: modeling neural control

We have been pursuing a modular approach to modeling and investigating the neural control of posture and movement. A modular approach is a practical and natural way of investigating the function and structure of the complex central nervous system (CNS). The modules can include skeletal dynamics, muscle dynamics with recruitment and force-generation characteristics, basic spinal cord neural circuits responsible for the local stretch reflex, interneuronal networks that provide modulation of various reflexes, various structures of brain circuits, and control strategy decision-making centers. The anatomical detail and complexity of each module can vary depending on the specific scientific question or motor task to be investigated and the extent of information available on the hierarchy. To demonstrate the modular approach, we present two examples that illustrate how biological motor control tasks can be investigated in varying degrees of complexity and detail. One example shows that a model with detailed anatomical structure and dynamic properties has to be developed to investigate the detailed interactions among several sensory feedback loops in the spinal cord. The other example shows that when investigating whole-body behavior, a grosser structured model with lumped components is more tractable so issues such as the interaction of spinal cord regulation and upper CNS intelligent control can be investigated.

Comparative analysis of black carbon in soils

Black carbon (BC), produced by incomplete combustion of fossil fuels and vegetation, occurs ubiquitously in soils and sediments. BC exists as a continuum from partly charred material to highly graphitized soot particles, with no general agreement on clear‐cut boundaries of definition or analysis. In a comparative analysis, we measured BC forms in eight soil samples by six established methods. All methods involved removal of the non‐BC components from the sample by thermal or chemical means or a combination of both. The remaining carbon, operationally defined as BC, was quantified via mass balance, elemental composition or by exploiting benzenecarboxylic acids as molecular markers or applying 13C MAS NMR (magic angle spinning nuclear magnetic resonance) spectroscopy. BC concentrations measured for individual samples vary over 2 orders of magnitude (up to a factor of 571). One possible explanation for this wide range of results is that the individual BC methods rely on operational definitions with clear‐cut but different boundaries and developed for specific scientific questions, whereas BC represents a continuum of materials with widely contrasting physicochemical properties. Thus the methods are inherently designed to analytically determine different parts of the continuum, and it is crucial to know how measurements made by different techniques relate to each other. It is clear from this preliminary comparative analysis that a collection of BC reference materials should be established as soon as possible 1 ) to ensure long‐term intralaboratory and interlaboratory data quality and 2) to facilitate comparative analyses between different analytical techniques and scientific approaches

The BIMA Survey of Nearby Galaxies (BIMA SONG)

BIMA SONG is a systematic imaging study of the 3 mm CO J = 1 → 0molecular emission within the centres and discs of 44 nearby spiral galaxies on size scales of a few hundred parsecs (6-9"). The overall goal of the survey is to study the role of molecular gas in the evolution of spiral galaxies. To this end, BIMA SONG addresses 1) the distribution and physical conditions of the molecular gas in galactic discs and its relation to star formation, 2) the effects of a stellar bar on the kinematics of molecular gas, including the possible inflow of gas along a bar, and 3) the distribution and role of molecular gas in the central few hundred parsecs of active and quiescent galaxies. The source list includes all (except M33and M31) 44 galaxies of Hubble types Sa–Sd, with declinations δ >−20°, visual magnitudes B < 11.0, velocities v hel <2000 km s-1, and inclinations i < 70°. Beyond the specific scientific questions we will address, this survey will provide a unique database for astronomers who study galaxies at all wavelengths.

Issues with biotechnology products in toxicologic pathology.

The emergence of the biotechnology industry and introduction of drugs derived from recombinant DNA technology has generated many new issues in approaches to preclinical safety evaluation and extrapolation of results to risk assessment in humans. Products or therapeutic approaches for consideration include hormones, growth factors, cytokines, monoclonal antibodies, vaccines, blood products, antisense, and gene therapy. In many instances the application of standard safety tests conventionally used for small molecules are of limited value or are inappropriate. Studies should be designed to answer specific scientific questions rather than simply to fulfill regulatory requirements. Special consideration must be given to study design and species selection in terms of biological activity and species specificity, implications of immunological responses in the animal studies, and effects of systemic administration of molecules at clinically relevant doses. A full understanding of the clinical relevance of toxicological and pathologic findings associated with administration of these molecules to laboratory animals requires definition of the pathogenic mechanism of lesion induction.

Research

The International Society of Hair Restoration Surgery, Scientific Committee is now accepting proposals for scientific research projects. A limited amount of funding through the Society will be available for selected research projects. Projects should be designed with a specific scientific question

The Po Valley Fog Experiment 1989.

An outline is presented here of the Po Valley Fog Experiment 1989, carried out within the EUROTRAC-GCE project. This experiment is a joint effort by several European research groups from 5 countries. The physical and chemical behaviour of the fog multiphase system was studied experimentally following the temporal evolution of the relevant chemical species in the different phases (gas, droplet, interstitial aerosol) and the evolution of micrometeorological and microphysical conditions, from the pre-fog situation through the whole fog evolution, to the post-fog period. Some general results, useful for describing the general features of the fog system, are presented here, while specific scientific questions on the different processes taking place within the system itself will be addressed in other companion papers of this same issue. DOI: 10.1034/j.1600-0889.1992.t01-4-00002.x

Restenosis: Animal models and morphometric techniques in studies of the vascular response to injury

Percutaneous transluminal coronary angioplasty has become a frequently used, clinically effective method for the revascularization of stenosed or occluded native arteries And vein grafts. However, the problem of restenosis, which occurs in 25% to 50% of patients who undergo intravascular intervention, continues to significantly affect the clinical utility of this procedure. It is apparent that many forms of vascular injury result in the cascade of events that lead to neointimal proliferation and restenosis. The pathogenesis of this restenosis process is not well understood. In vitro techniques and animal models are currently being used to elucidate some of the mechanisms of restenosis. The purpose of this discussion is to review the animal models currently used in vascular biology research and describe morphometric techniques that can be employed to evaluate these model systems. Proper model systems and accurate morphometric techniques are necessary to provide data that will answer the specific scientific questions that must be resolved in order to understand the pathogenesis of restenosis after vascular injury.

The Po Valley Fog Experiment 1989 An overview

An outline is presented here of the Po Valley Fog Experiment 1989, carried out within the EUROTRAC-GCE project. This experiment is a joint effort by several European research groups from 5 countries. The physical and chemical behaviour of the fog multiphase system was studied experimentally following the temporal evolution of the relevant chemical species in the different phases (gas, droplet, interstitial aerosol) and the evolution of micrometeorological and microphysical conditions, from the pre-fog situation through the whole fog evolution, to the post-fog period. Some general results, useful for describing the general features of the fog system, are presented here, while specific scientific questions on the different processes taking place within the system itself will be addressed in other companion papers of this same issue. DOI: 10.1034/j.1600-0889.1992.t01-4-00002.x

Hearing protector attenuation: A perspective view

The design, performance and evaluation of hearing protectors are matters of substantial current interest. The specific scientific questions which command attention include the accuracy of the shift in free field hearing threshold as a measure of protection, the relationship between physical measurements of sound attenuation with real heads and psycho-physical methods of measurement, the relationship between physical measurements with real and artificial heads, the acoustical behaviour of hearing protectors and the factors which limit their performance, and the relationship between hearing protector attenuation and speech intelligibility. These questions have received considerable attention during the past twenty years but are not yet fully answered.

A Course in Bayesian Statistics

A Course in Bayesian Statistics