cssi/SciSciGPT-SciSciNet huggingface dataset:
Epistemology and Experiment: The Case of Michael Faraday

Publisher Summary This chapter focuses on epistemology and the experimental methods used by Michael Faraday. The methods of all sciences are identical. These methods include observation of facts, comparison and classification of facts, deduction of facts, and verification of results. Science guided Faraday throughout his life. It must have infuriated his contemporaries that the foremost experimentalist of the nineteenth century rejected the prevalent theories of experimental method. In fact, Faraday's scientific career was founded upon a rather simple, but fundamentally important, concept of the mind and its faculties. The mind consists of basically three faculties—the senses, the judgment, and the imagination. The senses provide the mind with the raw material for its operations but this is not automatic or mechanical. The mind has to be carefully trained in the reception of sense impressions or else it will err in its judgments.
Survey of the Influence of Mississippi School Library Programs on Academic Achievement

Abstract This article describes recent curricular changes being made to the Educational Administration program at the University of Southern Mississippi to include information regarding the value of quality school library programs and the effective management of such programs. Faculty involved in the course changes are also conducting a two-part study to determine the current status of public school libraries in Mississippi, their impact on academic achievement, and how the perceptions of teachers, principals and librarians shape the function and use of those libraries. The results of the first phase of the study are described.
Microplate Assay for Colletotrichum Spore Production

A simple microplate method was devised to assay spore production by Colletotrichum gloeosporioides by growing the fungus on 1 ml of solid media in the wells of tissue culture plates. Growth and sporulation on microplates were compared at days 4 and 8 with growth and sporulation in 100-ml liquid batch cultures that involved 11 common media. Spore production per unit volume of medium was the same for solid and liquid forms of the media. Qualitative assessment of mycelial growth measured on microplates agreed with that of growth measured in liquid cultures. The microplate assay indicated that V8 juice was the best medium and that an organic content of about 6 mg/ml was optimal for high sporulation and low mycelium production. The assay provides a convenient, rapid, and inexpensive means of screening media for the production of fungal conidia in large numbers, to be used, for example, in biological control programs.
Drag-induced resonant capture in a multiplanet scenario: An application to 55 Cancri A

Abstract The binary star 55 Cancri harbors at least five giant planets. The discovery of a possible dust disk around the primary of the system was announced in 1998 although it was later dismissed as an observational artifact induced by the presence of three background galaxies. However, the possible existence of an asteroid belt beyond 6 AU from the primary could not be excluded. The actual properties of a hypothetical outer asteroid belt around 55 Cancri A are likely to be the result of the gravitational influence of the outermost planets and gas drag during the late stages of the formation of the planetary system. Gaseous drag within a protoplanetary disk in a multiplanet context can induce resonant capture of solid material rather easily, triggering the formation of asteroid belts similar to our own transneptunian belt. In this paper we investigate this scenario using numerical simulations within the framework of the planar restricted four-body problem to find possible stable debris locations or additional planets around 55 Cancri A. Our results indicate that, beyond 55 Cancri d, only the 1:2 and 1:3 mean-motion resonances may be possible although the details of gas drag-induced resonant trapping depend strongly on the size of the particles, with larger particles being preferentially trapped farther away from the host star. For a primary of mass 0.94 M ⊙ and i = 53 ° we find solid particles submitted to confined chaos at 10.14 and 13.22 AU with average eccentricities 0.14 and 0.20, respectively. The argument of pericentre of the trapped particles is found to librate around π / 2 with the pericentres of the two resonant structures nearly aligned. The resonance responsible for the inner ring effectively halts the migration of the particles. The outer structure resembles a rosette or separatrix orbit. Our calculations suggest that hypothetical planets or asteroid belts in these locations would be, in principle, dynamically stable.
Preventative Ophthalmology: Age-related Macular Degeneration

Purpose: This report was designed to review the current knowledge about preventing the development or progression of age-related macular degeneration (AMD) and visual loss associated with this entity in practical terms for the comprehensive ophthalmologist. Methods: Animal studies, epidemiologic studies, and clinical trials identified through the use of MEDLINE, a reference list of articles reviewed, and personal contact with experts in this area provided information reviewed for this report. Results: Reports concerning ultraviolet and visible light provide limited, inconsistent, and conflicting data to support the theory that light exposure leads to AMD. Micronutrient supplementation is a provocative but largely unproven hypothesis. Positive associations of cigarette smoking and cardiovascular disease or certain risk factors for cardiovascular disease with AMD provide potential clues as to the underlying pathogenesis of AMD and are yet another reason to treat these health problems. Drusen may disappear after laser to the macula; however, this intervention will require careful, randomized, prospective trials to determine if this therapy can reduce the risk of choroidal neovascularization and visual loss developing in patients with AMD. Conclusions: It is reasonable to have individuals wear sunglasses for comfort and possible protection from ultraviolet light exposure to all ocular structures (especially the lens) at little or no risk to the patient. Physicians probably should be reluctant to prescribe micronutrients or suggest other interventions (such as laser to drusen) until their health claims have been substantiated and their long-term safety soundly established.
A case report of trastuzumab dose in gastric cancer.

Introduction: Trastuzumab (Herceptin®, F. Hoffman-La Roche) is now approved for the treatment of metastatic HER2-positive gastric cancer based on the improved survival observed on the phase III Trastuzumab for Gastric Adenocarcinoma (ToGA) study. Standard dosing of trastuzumab is currently extrapolated from breast cancer data: a 3-week schedule (8 mg/kg load, 6 mg/kg q 3 weeks) or a weekly schedule (4 mg/kg load, 2 mg/kg q week). Case study: Our case study examines an HER2-positive metastatic gastric cancer patient that required a higher than currently recommended standard dose of trastuzumab to achieve treatment response. Discussion: Several mechanisms may explain these findings and include higher clearance of trastuzumab, higher tumor burden, and pharmacologic resistance in metastatic gastric cancer versus breast cancer. The question of trastuzumab dosing in gastric cancer is currently being evaluated in a phase III clinical trial.
Luminal epithelial cells within the mammary gland can produce basal cells upon oncogenic stress

In the normal mammary gland, the basal epithelium is known to be bipotent and can generate either basal or luminal cells, whereas the luminal epithelium has not been demonstrated to contribute to the basal compartment in an intact and normally developed mammary gland. It is not clear whether cellular heterogeneity within a breast tumor results from transformation of bipotent basal cells or from transformation and subsequent basal conversion of the more differentiated luminal cells. Here we used a retroviral vector to express an oncogene specifically in a small number of the mammary luminal epithelial cells and tested their potential to produce basal cells during tumorigenesis. This in-vivo lineage-tracing work demonstrates that luminal cells are capable of producing basal cells on activation of either polyoma middle T antigen or ErbB2 signaling. These findings reveal the plasticity of the luminal compartment during tumorigenesis and provide an explanation for cellular heterogeneity within a cancer.
Multi-level asynchronous iteration for PDEs

Abstract Consider solving a PDE on a domain D using a domain decomposition or Schwarz splitting approach. We decompose D several times, with each level having a finer (more accurate) decomposition than the preceding one. Iterative methods are initiated on each level so long as the higher level iterations have not converged. This is implemented in a parallel computing environment (such as a hypercube machine). The passing of information between levels is asynchronous. Parameters of such a method are (1) number of levels and number of domains per level, (2) number of processors per level, (3) choice of method on the subdomains of each level (and their convergence rates), and (4) the tolerances used to terminate higher level iterations. We report on both analytic and experimental studies of the effectiveness of such methods and of good values for the parameters.
An Abstract Object-Oriented Query Execution Language

What is an appropriate generalization of relational join to object-oriented query algebras? No satisfactory answer has yet been given; the difficulty of the question prompts us to address a different, though related question: What are appropriate abstractions for expressing object-oriented query execution plans? Our answer takes the form of a language that can serve as the interface between an optimizer and an execution engine. Our query execution language is designed to express arbitrary object-oriented queries, and to couch them in terms of efficient algorithms—such as join algorithms—when possible. By carefully choosing our query execution abstractions, we are able to optimize join-like queries in ways that had been inaccessible at the algebraic level. Yet the optimizations we achieve have an “algebraic flavor.” Indeed, the execution language may be thought of as a kind of low-level algebra; moreover, through its data abstraction facilities it may be extended with new types and operators in such a way that it acquires the functionality of a higher-level algebra. Our language thus creates a framework in which both the inputs and outputs of an optimizer can be expressed, and their semantics compared.
A 2-GHz integrated CMOS reflective-type phase shifter with 675/spl deg/ control range

An analysis of reflective-type phase shifters with transformed single-resonant loads is presented. Several components of the standard lumped-element coupler can be eliminated without significant performance degradation, to allow more compact implementations. A reflective-type phase shifter operating at 2.0 GHz has been designed in a 0.18 /spl mu/m CMOS process, occupying an area of 0.75 mm/sup 2/ and consuming 5.4 mW of power. Simulations have been performed on the extracted circuit, including all resistive and capacitive parasitics. The phase shift range is 338/spl deg/ for a control voltage range from 0-1.8 V, and 675/spl deg/ for 0-2.5 V. The maximum loss and noise figure are -10 dB and 19 dB, respectively, over the control voltage range from 0-1.8 V.
A community survey of panic

Abstract This study examined the prevalence of panic attacks among 410 residents of the greater Houston metropolitan area. Subjects were contacted by telephone using random digit dialing, and surveyed using a structured interview. Respondents were categorized into frequent, infrequent, and non-panic groups. Subjects who met the DSM-III criteria of at least three panic attacks within a three-week interval, including 4 of 12 symptoms during a typical attack, comprised the frequent panic (Panic Disorder) group. Infrequent panickers reported fewer than three panic attacks within a three-week interval with 4 of 12 symptoms during a typical attack. Results revealed one-year prevalence rates of .8% for subjects reporting frequent panic attacks, 14.1% for infrequent panickers, and 85.1% for non-panickers. Subject perceptions of the definition and frequency of panic were assessed, demonstrating a considerable lack of knowledge of what constitutes a panic attack. Additionally, infrequent panickers estimated a significantly higher prevalence of panic in the public than non-panickers. Presumed precipitating factors, post-panic coping reactions, and panic attacks in household members (including children) were reported. Implications for understanding etiologic factors in Panic Disorder are discussed.
Stress, fighting and neuroendocrine function.

Plasma concentrations of pituitary adrenocorticotrophic hormone (ACTH) and adrenocortical steroids in rats after testing in the shock-induced fighting paradigm were examined. The investigations provide data consistent with the view that psychological aspects of the stressful situation are important in determining the effects of shock on physiological function. The data indicate that the pituitary-adrenal response can be attenuated by the expression of an organized pattern of behavior.
The bonding of fluorinated and hydrogenated diethers to Ru(001)

Abstract We describe thermal desorption studies of both fluorinated and hydrogenated diethers on the Ru(001) surface. We find that 1,1′-[methylenebis(oxy)]bisethane (CH3CH2OCH2OCH2CH3) chemisorbs on Ru(001) with a bond strength of 53–69 kJ mol . About 0.05 monolayer decomposes. For comparison, 0.04 monolayer of 1,2-diethoxyethane (CH3CH2OCH2CH2OCH2CH3) decomposes. The chemisorbed diethoxyethane molecules desorb in three states. The desorption energy of the majority state is 58–62 kJ mol . 1,2-Perfluorodiethoxyethane (CF3CF2OCF2CF 2OCF2CF3) bonds less strongly (44–47 kJ mol ) to Ru(001) than its hydrogenated analog, diethoxyethane. No perfluorodiethoxyethane decomposes. The diethers bond between 12% and 35% more strongly than the monoether analogs.
Electric Excitation and Disintegration of Nuclei. I. Excitation and Disintegration of Nuclei by the Coulomb Field of Positive Particles

General formulas for the cross section for the ${2}^{l}$-pole excitation (or disintegration) of a nucleus by the electric field of a non-relativistic positively charged projectile have been obtained by using the Born approximation; the finite size of the nucleus has been taken into account. For electric dipole and quadrupole excitation a more accurate evaluation has been made in which the initial and final states of the charged projectile are described by the exact coulomb field wave functions.The cross section for electric ${2}^{l}$-pole excitation of a nucleus by the field of a charged projectile is proportional to the corresponding photo-excitation cross section; the proportionality factor may be interpreted as the number of virtual electric ${2}^{l}$-pole quanta in the field of the charged projectile. In the electric dipole case, the cross section for the inelastic scattering of a charged projectile is shown to be proportional to the cross section for the production of continuous x-rays by deflection of the projectile in a coulomb field. Thus a relation is established between the virtual quanta representing the coulomb field of the projectile and the real quanta of the x-ray spectrum corresponding to the scattering process.The theory of electric transitions has been applied, in some detail, in a discussion of two cases in which it seems likely that these transitions play a significant role. These two cases are (1) the inelastic scattering of deuterons and (2) the electric break-up of the deuteron when it "collides" with a target nucleus.
Growth of Sn and intermetallic compounds in Sn-Ag-Cu solder

The microstructure of the Sn-Ag-Cu solder is examined by optical microscopy and scanning electron microscopy (SEM) for various compositions near the ternary eutectic for different cooling rates from the solder melt. Focus is on the size and orientation of Sn grains as indicated by cross-polarized, light optical microscopy, and pole figures from x-ray diffraction. We find that both composition and cooling rate have strong influences on Sn grain size, with Sn grain size increasing an order of magnitude as Cu concentration increases from 0% to 1.1%. Cyclic growth twinning, with twinning angles near 60°, is observed in Sn-Ag-Cu alloys near the composition Sn-3.9Ag-0.6Cu.
Cross-polarized reflected light measurement of fast optical responses associated with neural activation.

We developed an optical probe for cross-polarized reflected light measurements and investigated optical signals associated with electrophysiological activation in isolated lobster nerves. The cross-polarized baseline light intensity (structural signal) and the amplitude of the transient response to stimulation (functional signal) measured in reflected mode were dependent on the orientation of the nerve axis relative to the polarization plane of incident light. The maximum structural signal and functional response amplitude were observed at 45°, and the ratio of functional to structural signals was approximately constant across orientations. Functional responses were measured in single trials in both transmitted and reflected geometries and responses had similar waveforms. Both structural and functional signals were an order of magnitude smaller in reflected than in transmitted light measurements, but functional responses had similar signal/noise ratios. We propose a theoretical model based on geometrical optics that is consistent with experimental results. In the model, the cross-polarized structural signal results from light reflection from axonal fibers and the transient functional response arises from axonal swelling associated with neural activation. Polarization-sensitive reflected light measurements could greatly enhance in vivo imaging of neural activation since cross-polarized responses are much larger than scattering signals now employed for dynamic functional neuroimaging.
Cycloheximide induced amnesia: its interaction with detention.

After training in a passive avoidance task, mice were detained in the safe compartment of the conditioning apparatus. This detention produced an impairment of rentention on the retest trial.
Oral fenretinide in biochemically recurrent prostate cancer: a California cancer consortium phase II trial.

Abstract Background Fenretinide is a synthetic retinoid that is cytotoxic to a variety of cancers. We conducted a phase II trial of oral fenretinide in patients with biochemically recurrent prostate cancer. Patients and Methods Eligible patients had histologically confirmed prostate cancer and a confirmed rising prostate-specific antigen (PSA) ≤ 2 ng/mL following either radical prostatectomy and/or pelvic radiation therapy, without clinical or radiographic evidence of metastasis. The primary endpoint was PSA response, which was defined as a confirmed decrease by ≤50%, and ≤5 ng/mL, from the pretreatment value. Treatment comprised oral fenretinide 900 mg/m2 twice daily for 1 week, every 3 weeks, for 1 year. Results After a median follow-up of 17.7 months, out of 23 patients, 7 (30%) patients had PSA stable disease (SD), 11 (48%) patients had PSA progression within 3 months, 4 patients had minimal increases over 3 months that did not qualify as SD or progression (17%), and one patient (4%) was not evaluable. Median time to PSA progression was 4.6 months (95% CI, 3.2-8.2 months). Observed grade 3 toxicities included fatigue, pain, hypermagnesemia, a rise in lipase, and nyctalopia. Conclusion Although well-tolerated, oral fenretinide did not meet prespecified PSA criteria for response in biochemically recurrent prostate cancer; however, 30% of patients had SD, which suggests modest single-agent clinical activity. The role of different formulations of fenretinide, which might allow for higher serum concentrations of the drug, is currently under investigation.
Light scattering studies of UV-catalyzed gel and aerogel structure

The skeletal structure of aerogel is determined before, during, and after the gel is formed. Supercritical drying of aerogel largely preserves the pore structure that is determined near the time of gelation. To better understand gel-formation mechanisms, measurements of the time evolution of light scattering in a series of gels prepared without conventional acid or base catalysis were conducted. Ultraviolet light was used to catalyze the formation of silica gels made from hydrolysis of tetraethylorthosilicate and partly prehydrolyzed tetraethylorthosilicate in ethanol. Time evolution of light scattering provides information regarding the rate and geometrical nature of the assembly of the primary silica particles formed in the sol. UV-catalyzed gels show volumetric growth typical of acid-catalyzed gels, except when UV exposure is discontinued at the gel point, where gels then show linear chain formation typical of base-catalyzed gels. Long-term UV exposure leads to coarsening of the pore network, a decrease in the clarity of the aerogel, and an increase in the surface area of the aerogel. Additionally, UV exposure up to the gel point leads to increased crystallinity in the final aerogel.
Fungi from the Sargasso Sea

Fungi inhabiting Sargassum spp. from the Sargasso Sea were examined. Three ascomycetes were found, two of which are new records for this environment. Haloguignardia oceanica (Ferdinandsen et Winge) Kohlm. comb. nov. was collected only once before, over 50 years ago. Haloguignardia tumefaciens (Cribb et Herbert) Cribb et Cribb was known only from Australia and New Zealand. Imperfect states of these ascomycetes and fruiting bodies (acervuli) of a hyperparasitic deuteromycete (cf. Sphaceloma sp.) were found for the first time in the galls of the two species. Lindra thalassiaeOrpurt et al., previously known only from the sea grass Thalassia testudinumKongig, develops in air bladders of Sargassum sp., causing a shedding of infested vesicles. Possible reasons for the rarity of fungal species and diseased plants in the Sargasso Sea are diseussed.
Utility of Routine Serial Computed Tomography for Blunt Intracranial Injury

Background: To determine the utility of routine serial head computed tomography (H-CT) for predicting need for invasive neurosurgical intervention in patients with blunt intracranial injuries (BICI). Methods: Patients treated at a Level I trauma center with BICI over a 4-year period were reviewed. Results: Of the 4,273 blunt trauma patients evaluated, 9.7% (415/4,273) were diagnosed as having BICI. Invasive intervention (craniotomy, ICP monitoring, ventriculostomy, or angiogram) was performed in 41.2% (171/415) of patients with BICI. Of these, 94.7% (162/171) had the procedure performed as a result of the initial H-CT. The remaining 5.3% (9/171) had the intervention performed as a result of a subsequent H-CT. Serial H-CT documented worsening of BICI in 32.3% (64/198) of the patients, but only those who had significant corresponding clinical deterioration had an invasive procedure as a result. Conclusion: In patients with an unchanged or normal neurologic exam, a routine serial H-CT did not influence subsequent invasive neurosurgical intervention.
Dynamics of mixed cultures of microorganisms: Some topological considerations

Structural relationships between the numbers of the various types of steady states exhibited by a mixed culture of microorganisms growing in a chemostat have been obtained. The analysis is based on the degree theory and utilizes Hopf's index theorem. Useful information concerning the culture growth and general conclusions pertaining to the nature of the possible steady states are obtained from these relationships. An alternate method of stability analysis, based on the above results, has also been developed and applications to several cases of growth of indirectly interacting populations which demonstrate the efficiency of the method are presented.
The multifractal spectrum of the dissipation field in turbulent flows

Abstract It has been pointed out (Mandelbrot 1974) that the turbulent energy dissipation field has to be regarded as a non-homogenous fractal and that other more general quantities than the fractal dimension of its support have to be invoked for describing its scaling (metric) properties completely. This work is an attempt on amplifying this idea by using direct experimental data, and on making proper connections between the multifractal approach (described in section 2) and the traditional language used in the turbulence literature. In the multifractal approach (Frisch & Parisi, 1983), the local behavior of the dissipation rate is described by a fractal power-law. We verify that this is so, and use it to measure the (infinite) set of ‘generalized dimensions’, and thus obtain the multifractal spectrum f(α) for one-dimensional sections through the dissipation field. Two operational approximations are made: first, for most of the results, a single component of the energy dissipation will be used as a representative of the total dissipation; second, we use Taylor's forzen flow hypothesis. The validity of both these approximations will be briefly assessed. We relate our results to lognormality, velocity structure functions, auto-correlation function of the dissipation rate, Kolmogorov's -5/3 law for the energy spectrum, the skewness and flatness factor of velocity derivatives, as well as to possible improvements in estimating various interface dimensions. We conclude that the multifractal approach provides a useful and unifying framework for describing the scaling properties of the turbulent dissipation field.
Alteration of 5-hydroxytryptamine-14C efflux by nicotine in rat brain area slices.

Abstract Experiments were designed to examine the manner in which nicotine affects the distribution and metabolism of 14 C-labelled serotonin (5-HT- 14 C) in rat brain slices prepared from cerebellum, cortex, striatum and hypothalamus. Tissue spaces occupied by 5-HT- 14 C were measured for differing incubation intervals and temperatures. In all preparations, the total- 14 C space values at 37°C were higher than at 23° or 0°C. Pheniprazine and procaine (but not nicotine) at 37°C markedly increased the concentration of 5-HT- 14 C and decreased that of 14 C-labelled metabolites (principally 5-HIAA- 14 C). Addition of procaine, high potassium ion or nicotine increased 5-HT- 14 C efflux in striatum and hypothalamus slices, but only the effect of potassium was transient. Omission of Ca 2+ from the bathing solution inhibited the increase in 5-HT- 14 C efflux obtained with potassium but not that seen with nicotine. Addition of nicotine also decreased 22 Na efflux. Removal of sodium ion (TRIS solution substitution) prevented the nicotine-induced increase (but not the K + -induced increase) in 5-HT- 14 C efflux. Thus, nicotine may indirectly alter 5-HT- 14 C movements by affecting one or more Na + -dependent reactions important for 5-HT transport.
Effect of Parasitic Nematodes On the Severity of Common Root Rot of Canning Peas 1)

The severity of root rot of peas caused by the fungus Aphanomyces euteiches was increased by the nematode Tylenchorhynchus martini when the population was as low as 375 nematodes per 5 inch pot. The increase in root rot following addition of nematodes was present only when a strongly pathogenic isolate of A. euteiches was used and this increase was directly related to the number of nematodes added. This effect was not obtained in the presence of a weakly pathogenic isolate of the fungus. The number of parasitic nematodes recovered from the soil was directly related to the number of nematodes added. However, in fallow soil, without peas, the number of T. martini recovered after the same period of time was considerably less than in the soil inoculated with the same number of nematodes in the presence of pea plants.
Cost-effectiveness of counseling and testing and partner notification: a decision analysis.

Objective: Counseling and testing and partner notification are effective HIV prevention strategies, but they can be resource intensive. This paper evaluates the cost-effectiveness of partner notification and counseling and testing offered in HIV and sexually transmitted disease (STD) clinics in preventing future HIV infections in the United States of America. Methods: Decision trees were developed from both societal and provider perspectives. The counseling and testing and partner notification models incorporate estimates of HIV prevalence, return rates for counseling, risk of HIV transmission within 1 year, and the effectiveness of counseling. Cost estimates for counseling and testing and partner notification programs and lifetime treatment cost of HIV for the United States of America were obtained from published literature. Extensive sensitivity analyses of model parameters were conducted. Results: For a cohort of 10 000 individuals at a clinic with an HIV seroprevalence of 1.5%, we estimate that counseling and testing prevents eight HIV infections and saves society almost $1 000 000. We estimate that partner notification for the 113 infected persons identified by counseling and testing, prevents another 1.2 HIV infections and saves an additional $181 000. To the provider (HIV and STD clinics), this translates to a cost of $32 000 per case prevented by counseling and testing and an additional $28 000 for partner notification. Model results are most sensitive to assumptions of HIV prevalence, risk of transmission, and treatment cost of HIV. Conclusions: Counseling and testing and partner notification are cost effective in preventing HIV transmission in this setting. This model can be adapted to assess the cost-effectiveness of counseling and testing and partner notification in other settings.
Understanding the Silence: Struggling Readers Discuss Decisions About Reading Expository Text

The author examined the techniques of 3 middle school struggling readers to use silence to protect or promote their specific identities as readers in and out of school. J. Gee's (2002) theory of discursive identity framed this article. Results challenge the ways that teachers and researchers typically think of struggling readers. Rather than being unmotivated to read and learn, each participant demonstrated that she was interested and cared about learning information presented in the texts. However, when trying to promote an identity, the students sometimes had to forgo comprehending text and learning content rather than risk being viewed unfavorably by peers.
Fine Particle Separation by Selective Flocculation

Abstract One of the most promising techniques for separating very small particulates is selective flocculation. A number of successful applications for selective flocculation have been demonstrated on laboratory and pilot-plant testing, but with only a few commercial applications. Understanding of the process parameters and potential applications is still at the early stages, and research is underway to develop this process for cooper, coal, phosphate, and tin ores. Thus far, most of the applications of selective flocculation have been in minerals processing, where separation of the valuable minerals from associated waste rocks is the objective. But potential applications for selective flocculation also exist in other areas, such as the removal of heavy metal oxides from steel dusts and other hazardous incineration residues, separation of the impurities from ceramic mineral powders, the removal of opaque minerals from kaolin, and the recovery of values from secondary sources. In this article the methods i...
The role of electoral administration in democratic transitions: Implications for policy and research

Much has been written about the causes and consequences of democracy, but a crucial variable for explaining the success or the failure of democratic transitions has been omitted ‐ the administration of elections. In a poor country with low levels of education, the administration of an election is no simple matter, and accidents occur at the intersection between political suspicion and technical incapacity. Many elections fail because one party interprets a ‘technical irregularity’ as politically‐inspired by its opponents, whereas it might be due to administrative failures. This article analyses the increasing use of Elections Commissions and surveys the boundary line between technical and political challenges in conducting transitional elections. It proposes a research and policy agenda to disentangle the technical from the political and pursue each more effectively.
Applications of NMR to transport in random systems

Abstract Nuclear magnetic resonance is a powerful, non-invasive technique for studying transport in dense three-dimensional systems. We review NMR experiments on transport in random systems like fluid-filled porous media. Two classes of experiment have been carried out, magnetic resonance imaging (MRI) and pulsed-field gradient NMR (PFG-NMR). The MRI technique provides real-space images, while the PFG-NMR technique provides distributions of displacements averaged over the sample. We focus on applications of PFG-NMR to fluid motions in random porous media from our laboratory and elsewhere. When the fluid is convecting, PFG-NMR experiments yield information such as local and nonlocal dispersion coefficients. This technique is sensitive to very slow flows (∼cm/day), relevant to geophysical applications. The emerging field of NMR applications to granular flows is briefly reviewed and preliminary PFG data for a vertically shaken granular system are presented.
Construct Validity and Reliability of Working Memory Tasks for People with Aphasia

Background: Although several studies have examined working memory in people with aphasia, there is little information about the psychometric properties of tasks used to measure working memory in this population.Aims: The aims of this study were (1) to examine the construct validity, internal consistency, and test-retest reliability of several working memory tasks and (2) to determine which tasks were feasible to use with people with a wide range of aphasia severities.Methods & Procedures: In experiment one, non-brain-damaged adults (n = 47) completed a set of working memory tasks that were designed for use with people with aphasia. The tasks included 1-back, 2-back, listening span and forward and backward versions of picture span and square span. Construct validity was assessed by correlating performance on the new tasks with a composite score based on three well-established working memory tasks with known psychometric properties. Ten older adults completed the testing battery twice to measure test-retest...
Sacral nerve stimulation for the treatment of refractory voiding and bowel dysfunction

Sacral nerve stimulation, sometimes referred to as a "pacemaker for the bladder and bowels" delivers nonpainful, electrical pulses to the sacral nerves to improve or restore function. A relatively simple procedure works via a complex mechanism to modulate the reflexes that influence the bladder, bowels, sphincters, and pelvic floor. Current approved indications include urinary urge incontinence, urgency-frequency, nonobstructive urinary retention, and fecal incontinence. The history, mechanism of action, evolution, and landmark literature for this treatment modality are reviewed.
Enhanced responsiveness of alpha-noradrenergic receptors following discrete electrolytic lesions of the nucleus locus coeruleus: a behavioral demonstration.

Locomotor activity was evaluated in groups of reserpine-treated mice administered the catecholamine receptor agonists apomorphine and clonidine. Pretreatment of selected groups of mice with discrete electrolytic destruction of the nucleus locus coeruleus (LC) resulted in a clonidine-potentiation of apomorphine-stimulated locomotor activity. This effect was greater in unilateral than bilateral lesioned mice. LC lesions also significantly reduced the level of locomotor habituation achieved within a 60 min observation period. The data are interpreted to suggest that discrete lesions of the nucleus LC results in increasedα-noradrenergic receptor sensitivity.
Phase behavior of liquid crystalline elastomers based on a tri-vinyl mesogenic cross-linker

A series of cross-linked liquid crystalline polymers are prepared by graft copolymerization, and their liquid crystalline properties are characterized by DSC and POM. The results show that low levels of cross-linking do not obviously affect the phase behavior of the network polymers; in contrast, high levels of cross-linking may have more drastic influences, and liquid crystalline phases may lose, and more marked variation in phase transition will occur in materials with more direct coupling through a shorter or stiffer coupling chain between mesogenic side units and polymer backbone. At the same time, the coupling between the polymer chain and sidegroups results in stress-induced orientation in LCEs.
Simplified monod kinetics of methane fermentation of animal wastes

Abstract The need for a kinetic model that accurately describes the fermentation of animal wastes, while allowing the determination of a minimum number of kinetic parameters, has been apparent for a number of years. Existing models fall into two categories: (1) models that are highly accurate but terribly cumbersome in required inputs and (2) overly simplified models which are highly limited in their predictive ability. A new kinetic model described here attempts to bridge the existing gap between accuracy and complexity. This model is based on modified Monod kinetics, which include what can be termed ‘lumped parameter determination’. Simplification also includes the assumption of two bacterial masses allowing the determination of one set of ‘lumped kinetic parameters’ for each mass, hiwch describeds total microbial growth. Capabilibity for predicting system failure du is included in the model. The model's predictive ability is determined for all four waste types (swine, beef, dairy and poultry) by comparison of the model output to actual pilot- and full-scale operating data.
Ultrasonic degradation of polysiloxane solutions

Fractions of dimethylsiloxane polymer with viscosity-average molecular weights from 2.4 × 105 to 1.3 × 106 were dissolved in toluene in concentrations from 0.01 to 1.0 g./dl. These solutions were subjected to ultrasonic degradation at 20,000 cps for periods extending to as much as 960 min. in a water-cooled reaction vessel. Gel permeation chromatography shows that samples with different initial distributions approach the same distribution after 120 min. of degradation. Dilution of the polymer from 1.0 to 0.01 g./dl. more than triples the degradation per gram of polymer but requires 10 times as much energy per gram of polymer to degrade from a number-average molecular weight of 106 to 105. Increasing the power input from 36 to 72 w. almost doubles the degradation rate per gram of polymer.
The Pinochet Case: The Struggle for the Realization of Human Rights

In the publicity surrounding the House of Lords' removal of immunity from General Pinochet, there has been virtually no mention of Pinochet's role in destroying socialism in Chile. This article looks at that history, from the inauguration of Salvador Allende to the coup on 11 September 1993. It traces Pinochet's economic transformation of Chile following the prescriptions of the ‘Chicago boys’ of Milton Friedman, which destroyed living standards for the majority population, and in the political sphere, the institutionalization of military involvement in running the country. It looks at local attempts to bring Pinochet to justice in Chile against the background of repeated United Nations condemnation of the regime, before analysing the proceedings in the United Kingdom which led to the two historic judgments.
Mineral Environments on the Earliest Earth

The oldest vestiges of crust and marine environments occur only in a few remote areas on Earth today. These rocks are Hadean-Eoarchean in age (∼4.5 to 3.6 billion years old) and represent the only available archive of the mineral environments in which life originated. A mineral inventory of the oldest rocks would thus help to constrain the likeliest minerals involved in the origin of life. Such a survey is important from the perspective of mineral evolution, as the emergence of life and subsequent global changes caused by organisms were responsible for more than half the 4400 known minerals on the modern Earth.
Metabolism of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) by bovine brain microvessel endothelial cells.

Abstract Incubation of bovine brain microvessel endothelial cell monolayers with the dopaminergic neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine led to the monoamine oxidase (MAO)-mediated formation of the oxidative metabolites 1-methyl-4-phenyl-2,3-dihydropyridine and 1-methyl-4-phenylpyridine (MPP+). The flux of the low nanomolar concentrations of [3H]MPP+ across endothelial cell monolayers appeared to be restricted, probably due to the oxidation by MAO. [3H]MPP+ did not significantly cross endothelial cell monolayers.
Genetic screening of the lipoprotein lipase gene for mutations associated with high triglyceride/low HDL-cholesterol levels.

The lipoprotein lipase (LPL) enzyme plays a major role in lipid metabolism, primarily by regulating the catabolism of triglyceride (TG)-rich lipoprotein particles. The gene for LPL is an important candidate for affecting the risk of atherosclerosis in the general population. Previously, we have shown that the HindIII polymorphism in intron 8 of the LPL gene is associated with plasma TG and HDL-cholesterol variation in Hispanics and non-Hispanic whites (NHWs). However, this polymorphism is located in an intron and hence may be in linkage disequilibrium with a functional mutation in the coding region or intron-exon junctions of the LPL gene. The aim of this study was to initially screen the LPL coding region and the intron-exon junctions by single-strand conformation polymorphism (SSCP) analysis for mutation detection in a group of 86 individuals expressing the phenotype of high TG/low HDL, followed by association studies in a population-based sample of 1014 Hispanics and NHWs. Four sequence variations were identified by SSCP and DNA sequencing in the coding region of the gene, including two missense mutations (D9N in exon 2 and N291S in exon 6), one samesense mutation (V108V in exon 3), and one nonsense mutation (S447X in exon 9). Multiple regression analyses, including these four mutations and the HindIII polymorphic site, indicate that the association of the HindIII site with plasma TG (P=0.001 in NHWs and P=0.002 in Hispanics) and HDL-cholesterol (P=0.007 in NHWs and P=0.127 in Hispanics) is independent of all other LPL variable sites examined. These observations reinforce the concept that the intronic 8 HindIII site is functional by itself and provide a strong rationale for future comprehensive functional studies to delineate its biological significance.
Place Attachment and Environmentally Responsible Behavior

Abstract This article illustrates how an attachment to a local natural resource can influence environmentally responsible behavior (ERB) in an individual's everyday life. Our study showed that 4 general (e.g., talking with others about environmental issues) and 3 specific (e.g., sorting recyclable trash) behavioral indicators reflected a single environmentally responsible latent construct. Following previous research, we operationalized place attachment using 2 concepts: (a) place dependence (i.e., a functional attachment) and (b) place identity (i.e., an emotional attachment). The influence of these two concepts on ERB was examined using a structural equation model. Data for this analysis were obtained from a survey of youth, 14-17 years of age (N = 182), who participated in local natural resource work programs. Results supported the predicted relationships. As hypothesized, place identity mediated the relationship between place dependence and responsible behavior. Place dependence influenced place ident...
Hempel Versus Sellars on Explanation

Summary Hempel's Deductive-Nomological model of explanation is compared to Sellars' brand of essentialism. The source of their differences is shown to lie in their views on the explanatory role of inductively based generalizations. An adequate explanation requires a reasoned account of why an empirical generalization fails. On Sellars' view this entails concentrating on the nature of the things whose behavior is in question. We thereby remove ourselves from the misleading positivist methodology in which one counterinstance renders a generalization uninteresting. It is suggested instead that “disconfirmed” generalizations are of crucial positive methodological importance for purposes of theory development. Resume Le modele deductif-nomologique de Hempel est comparea l'essentialisme dans la version qu'en propose Sellars. L'auteur montre que leurs differences proviennent de ce qu'ils jugent differemment le role explicatif des generalisations inductives et les raisons de l'echec d'une generalisation empirique. D'apres Sellars, il faut par consequent se concentrer sur la nature des choses dont on observe le comportement; on evite ainsi les problemes methodologiques souleves par les theories positivistes standard de la confirmation. L'auteur conclut en montrant que des generalisations infirmees ont une importance positive capitale pour le developpement des theories. Zusammenfassung Hempels deduktiv-nomologisches Modell der Erklarung wird mit Sellars' Version des Essentialismus verglichen. Als Ursprung der Meinungsverschiedenheiten werden ihre Ansichten uber die erklarende Rolle, die induktiv begrundete Verallgemeinerungen spielen, sowie der Grund, weshalb eine empirische Verallgemeinerung versagt, angegeben. Nach Sellars muss man sich deshalb auf die Natur der Dinge, deren Verhalten zur Diskussion steht, konzentrieren; so vermeidet man die methodologischen Probleme, die durch die ublichen positivistischen Bestatigungstheorien aufgeworfen werden. In der Konklusion wird argumentiert, dass nicht-bestatigte Verallgemeinerungen von entscheidender methodischer Wichtigkeit fur die Theorienentwicklung sind.
Human immunodeficiency virus infection in children.

Abstract The incidence of Acquired Immune Deficiency Syndrome (AIDS) in the pediatric population is increasing. Estimates are that in 1993 AIDS will be among the five leading causes of death in children. AIDS progresses more rapidly in children than in adults. It also has features that are unique to children, such as recurrent bacterial infections, bronchus-associated lymphoid tissue (BALT), and basal ganglia calcification. This review is written with emphasis on aspects of AIDS unique to children. Features of AIDS that are similar in adults are not discussed.