Showing papers by "University of British Columbia published in 1994"
Tohoku University1, University of Zurich2, Lawrence Berkeley National Laboratory3, Stanford University4, College of William & Mary5, University of Urbino6, CERN7, Budker Institute of Nuclear Physics8, University of California, Irvine9, Cornell University10, Argonne National Laboratory11, ETH Zurich12, Tata Institute of Fundamental Research13, Hillsdale College14, Spanish National Research Council15, Ohio State University16, University of Notre Dame17, Kent State University18, University of California, San Diego19, University of California, Berkeley20, University of Minnesota21, University of Alabama22, University of Helsinki23, Los Alamos National Laboratory24, California Institute of Technology25, George Washington University26, Syracuse University27, Lawrence Livermore National Laboratory28, Oklahoma State University–Stillwater29, University of Washington30, Max Planck Society31, Boston University32, University of California, Los Angeles33, Royal Holloway, University of London34, Université Paris-Saclay35, University of Pennsylvania36, University of Illinois at Urbana–Champaign37, University of Bristol38, University of Tokyo39, University of Delaware40, Carnegie Mellon University41, University of California, Santa Cruz42, Karlsruhe Institute of Technology43, Heidelberg University44, Florida State University45, University of Mainz46, University of Edinburgh47, Brookhaven National Laboratory48, Durham University49, University of Lausanne50, Massachusetts Institute of Technology51, University of Southampton52, Nagoya University53, University of Oxford54, Northwestern University55, University of British Columbia56, Columbia University57, Lund University58, University of Sheffield59, University of California, Santa Barbara60, Iowa State University61, University of Alberta62, University of Cambridge63
TL;DR: This biennial Review summarizes much of Particle Physics using data from previous editions, plus 2205 new measurements from 667 papers, and features expanded coverage of CP violation in B mesons and of neutrino oscillations.
Abstract: This biennial Review summarizes much of Particle Physics. Using data from previous editions, plus 2205 new measurements from 667 papers, we list, evaluate, and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons. We also summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and reviews of topics such as the Standard Model, particle detectors, probability, and statistics. This edition features expanded coverage of CP violation in B mesons and of neutrino oscillations. For the first time we cover searches for evidence of extra dimensions (both in the particle listings and in a new review). Another new review is on Grand Unified Theories. A booklet is available containing the Summary Tables and abbreviated versions of some of the other sections of this full Review. All tables, listings, and reviews (and errata) are also available on the Particle Data Group website: http://pdg.lbl.gov.
5,143 citations
Thomas Jefferson University1, Harvard University2, Scripps Health3, University of Pittsburgh4, University of British Columbia5, Memorial Hospital of South Bend6, Yale University7, Arizona Heart Institute8, University of Toronto9, St Lukes Episcopal Hospital10, Johns Hopkins University11, Lenox Hill Hospital12, University of Pennsylvania13, University of Texas at San Antonio14, Cleveland Clinic15
TL;DR: In selected patients, placement of an intracoronary stent, as compared with balloon angioplasty, results in an improved rate of procedural success, a lower rate of angiographically detected restenosis, a similar rate of clinical events after six months, and a less frequent need for revascularization of the original coronary lesion.
Abstract: Background Coronary-stent placement is a new technique in which a balloon-expandable, stainless-steel, slotted tube is implanted at the site of a coronary stenosis. The purpose of this study was to compare the effects of stent placement and standard balloon angioplasty on angiographically detected restenosis and clinical outcomes. Methods We randomly assigned 410 patients with symptomatic coronary disease to elective placement of a Palmaz-Schatz stent or to standard balloon angioplasty. Coronary angiography was performed at base line, immediately after the procedure, and six months later. Results The patients who underwent stenting had a higher rate of procedural success than those who underwent standard balloon angioplasty (96.1 percent vs. 89.6 percent, P = 0.011), a larger immediate increase in the diameter of the lumen (1.72 ±0.46 vs. 1.23 ±0.48 mm, P<0.001), and a larger luminal diameter immediately after the procedure (2.49 ±0.43 vs. 1.99 ±0.47 mm, P<0.001). At six months, the patients with stented ...
4,300 citations
TL;DR: This paper distinguishes between ‘component’ and ‘architectural’ competence, and using internal firm data at the program level from 10 major pharmaceutical companies shows that together the two forms of competence appear to explain a significant fraction of the variance in research productivity across firms.
Abstract: Renewed interest in the resource-based theory of the firm has focused attention on the role of heterogeneous organizational ‘competence’ in competition. This paper attempts to measure the importance of these effects in the context of pharmaceutical research. We distinguish between ‘component’ and ‘architectural’ competence, and using internal firm data at the program level from 10 major pharmaceutical companies show that together the two forms of competence appear to explain a significant fraction of the variance in research productivity across firms. Our results raise some intriguing questions about the nature of competencies and the ways in which they diffuse over time.
2,675 citations
Proceedings Article•
12 Sep 1994TL;DR: The analysis and experiments show that with the assistance of CLAHANS, these two algorithms are very effective and can lead to discoveries that are difficult to find with current spatial data mining algorithms.
Abstract: Spatial data mining is the discovery of interesting relationships and characteristics that may exist implicitly in spatial databases In this paper, we explore whether clustering methods have a role to play in spatial data mining To this end, we develop a new clustering method called CLAHANS which is based on randomized search We also develop two spatial data mining algorithms that use CLAHANS Our analysis and experiments show that with the assistance of CLAHANS, these two algorithms are very effective and can lead to discoveries that are difficult to find with current spatial data mining algorithms Furthermore, experiments conducted to compare the performance of CLAHANS with that of existing clustering methods show that CLAHANS is the most efficient
1,999 citations
TL;DR: Although bacterial conjugation once was believed to be restricted in host range, it now appears that this mechanism of transfer permits genetic exchange between many different bacterial genera in nature.
Abstract: The emergence of multidrug-resistant bacteria is a phenomenon of concern to the clinician and the pharmaceutical industry, as it is the major cause of failure in the treatment of infectious diseases. The most common mechanism of resistance in pathogenic bacteria to antibiotics of the aminoglycoside, beta-lactam (penicillins and cephalosporins), and chloramphenicol types involves the enzymic inactivation of the antibiotic by hydrolysis or by formation of inactive derivatives. Such resistance determinants most probably were acquired by pathogenic bacteria from a pool of resistance genes in other microbial genera, including antibiotic-producing organisms. The resistance gene sequences were subsequently integrated by site-specific recombination into several classes of naturally occurring gene expression cassettes (typically "integrons") and disseminated within the microbial population by a variety of gene transfer mechanisms. Although bacterial conjugation once was believed to be restricted in host range, it now appears that this mechanism of transfer permits genetic exchange between many different bacterial genera in nature.
1,663 citations
TL;DR: The Personal Involvement Inventory (PII) as discussed by the authors is a context-free measure applicable to involvement with products, with advertisements, and with purchase situations, and it has been shown that the PII may be reliably reduced from twenty items to ten items.
Abstract: The conceptualization of the Personal Involvement Inventory was a context-free measure applicable to involvement with products, with advertisements, and with purchase situations. The empirical work to develop this measure was mainly validated with respect to product categories. This paper extends the construct validation of the PII to involvement with advertisements and also demonstrates that the PII may be reliably reduced from twenty items to ten items. There is some indication the revised PII may then be broken into two subscales representing a cognitive and affective grouping.
1,562 citations
TL;DR: This work has shown that with the use of the bacteriophage-derived, site-specific recombinase Cre in a transgenic approach, the same mutation can be selectively introduced into a particular cellular compartment-in this case, T cells.
Abstract: Deletion of the promoter and the first exon of the DNA polymerase beta gene (pol beta) in the mouse germ line results in a lethal phenotype. With the use of the bacteriophage-derived, site-specific recombinase Cre in a transgenic approach, the same mutation can be selectively introduced into a particular cellular compartment-in this case, T cells. The impact of the mutation on those cells can then be analyzed because the mutant animals are viable.
1,542 citations
TL;DR: In this paper, a simple static model of North-South trade is developed to examine linkages between national income, pollution, and international trade, and it is shown that the higher income country chooses stronger environmental protection, and specializes in relatively clean goods.
Abstract: A simple static model of North-South trade is developed to examine linkages between national income, pollution, and international trade. Two countries produce a continuum of goods, each differing in pollution intensity. We show that the higher income country chooses stronger environmental protection, and specializes in relatively clean goods. By isolating the scale, composition, and technique effects of international trade on pollution, we show that free trade increases world pollution; an increase in the rich North's production possibilities increases pollution, while similar growth in the poor South lowers pollution; and unilateral transfers from North to South reduce worldwide pollution.
1,465 citations
TL;DR: A review of the methods used in that research raises questions of its ecological, convergent, and internal validity as mentioned in this paper, as well as other features such as forced-choice response format, within-subject design, preselected photographs of posed facial expressions, and other features of method are each problematic.
Abstract: Emotions are universally recognized from facial expressions--or so it has been claimed. To support that claim, research has been carried out in various modern cultures and in cultures relatively isolated from Western influence. A review of the methods used in that research raises questions of its ecological, convergent, and internal validity. Forced-choice response format, within-subject design, preselected photographs of posed facial expressions, and other features of method are each problematic. When they are altered, less supportive or nonsupportive results occur. When they are combined, these method factors may help to shape the results. Facial expressions and emotion labels are probably associated, but the association may vary with culture and is loose enough to be consistent with various alternative accounts, 8 of which are discussed.
1,449 citations
Book•
01 Jan 1994TL;DR: Part I. Morphology, Life Histories and Morphogenesis: the plants and their environments, seaweed morphology and anatomy, and Seaweed communities - application of ecology and physiology.
Abstract: Part I. Morphology, Life Histories and Morphogenesis: 1. Introduction: the plants and their environments 2. Seaweed morphology and anatomy 3. Seaweed cells 4. Seaweed genetics and molecular biology 5. Seaweed life histories 6. Settlement and germination 7. Thallus morphogenesis 8. Synopsis Part II. Seaweed Communities: 1. Seaweed communities T. A. Norton et al. 2. Intertidal zonation patterns 3. Submerged zonation patterns 4. Some other seaweed habitats and communities P. H. Nienhuis et al. 5. Community analysis 6. Synopsis Part III. Biotic Interactions: 1. Competition 2. Grazing 3. Symbiosis 4. Synopsis Part IV. Light and Photosynthesis: 1. An overview of photosynthesis 2. Irradiance 3. Light harvesting 4. Carbon fixation: the 'dark reactions' of photosynthesis 5. Seaweed polysaccharides 6. Carbon translocation 7. Photosynthetic rates and primary productivity 8. Synopsis Part V. Nutrients: 1 Nutrient requirements 2. Nutrient availability in seawater 3. Pathways and barriers to ion entry 4. Nutrient uptake kinetics 5. Uptake, assimilation and metabolic role of essential nutrients 6. Long distance transport translocation 7. Growth kinetics 8. Effects of nutrient supply 9. Synopsis Part VI. Temperature and Salinity: 1. Natural ranges of temperature and salinity 2. Temperature effects 3. Biochemical and physiological effects of salinity 4. Dessication 5. Salinity-temperature interactions and estuarine distribution 6. Synopsis Part VII. Water Motion: 1. Water flow over surfaces 2. Wave action 3. Synopsis Part VIII. Pollution: 1. Introduction 2. Thermal pollution 3. Heavy metals 4. Oil 5. Synthetic organic chemicals 6. Complex wastes and eutrophication 7. Synopsis Part IX. Seaweed Mariculture: 1. Introduction 2. Porphyra mariculture 3. Lamineria mariculture 4. Undaria mariculture 5. Eucheuma and Kappaphycus mariculture 6. Other seaweeds 7. Domestication of seaweeds - application of ecology and physiology 8. Seaweed biotechnology 9. Synopsis Appendix: Taxonomic classification of algae mentioned in the text P. C. Silva and R. L. Moe Index.
1,183 citations
TL;DR: Based on quantitative comparison, the chirp scaling algorithm provides image quality equal to or better than the precision range/Doppler processor, as defined by the system bandwidth.
Abstract: A space-variant interpolation is required to compensate for the migration of signal energy through range resolution cells when processing synthetic aperture radar (SAR) data, using either the classical range/Doppler (R/D) algorithm or related frequency domain techniques. In general, interpolation requires significant computation time, and leads to loss of image quality, especially in the complex image. The new chirp scaling algorithm avoids interpolation, yet performs range cell migration correction accurately. The algorithm requires only complex multiplies and Fourier transforms to implement, is inherently phase preserving, and is suitable for wide-swath, large-beamwidth, and large-squint applications. This paper describes the chirp scaling algorithm, summarizes simulation results, presents imagery processed with the algorithm, and reviews quantitative measures of its performance. Based on quantitative comparison, the chirp scaling algorithm provides image quality equal to or better than the precision range/Doppler processor. Over the range of parameters tested, image quality results approach the theoretical limit, as defined by the system bandwidth. >
TL;DR: In this article, the authors argue that subitizing exploits a limited capacity parallel mechanism for item individuation, the FINST mechanism, associated with the multiple target tracking task, and that the position of the attentional focus, as manipulated by cue validity, has a greater effect on counting.
Abstract: "Subitizing," the process of enumeration when there are fewer than 4 items, is rapid (40-100 ms/item), effortless, and accurate. "Counting," the process of enumeration when there are more than 4 items, is slow (250-350 ms/item), effortful, and error-prone. Why is there a difference in the way the small and large numbers of items are enumerated? A theory of enumeration is proposed that emerges from a general theory of vision, yet explains the numeric abilities of preverbal infants, children, and adults. We argue that subitizing exploits a limited-capacity parallel mechanism for item individuation, the FINST mechanism, associated with the multiple target tracking task (Pylyshyn, 1989; Pylyshyn & Storm, 1988). Two kinds of evidence support the claim that subitizing relies on preattentive information, whereas counting requires spatial attention. First, whenever spatial attention is needed to compute a spatial relation (cf. Ullman, 1984) or to perform feature integration (cf. Treisman & Gelade, 1980), subitizing does not occur (Trick & Pylyshyn, 1993a). Second, the position of the attentional focus, as manipulated by cue validity, has a greater effect on counting than subitizing latencies (Trick & Pylyshyn, 1993b).
TL;DR: The intrinsic difference in magnetic resonance spin‐spin relaxation time, T2, between water associated with myelin sheaths and water in other central nervous system tissue is exploited to measure myelin water content within any region of an image or to generate indirectly a myelin map of the brain.
Abstract: We exploit the intrinsic difference in magnetic resonance spin-spin relaxation time, T2, between water associated with myelin sheaths and water in other central nervous system tissue in order to measure myelin water content within any region of an image or to generate indirectly a myelin map of the brain. In normal volunteers, myelin water maps give the expected myelin distribution. In multiple sclerosis patients, lesions exhibit different myelin water contents providing insight into the demyelination process unavailable from conventional magnetic resonance images. In vivo myelin measurement has important applications in the clinical management of multiple sclerosis and other white matter diseases.
TL;DR: The determination of a large number of three-dimensional structures of Glycosidases, both free and in complex with ligands, has provided valuable new insights into glycosidase catalysis, especially when coupled with results from studies of specifically labelled glyCosidases and kinetic analyses of point mutants.
TL;DR: It is reported that the β-subunit binds to the cytoplasmic linker between repeats I and II of the dihydropyridine-sensitive α 1-sub units from skeletal and cardiac muscles, and also with the more distantly related neuronal α 1A and ω-conotoxin GVIA-sensitive aα 1B-subunits.
Abstract: THE β-subunit is an integral component of purified voltage-sensitive Ca2+ channels1–3. Modulation of Ca2+ channel activity by the β-subunit, which includes significant increases in transmembrane current and/or changes in kinetics, is observed on coexpression of six α1-subunit genes with four β-subunit genes in all α1- β combinations tested4–12. Recent reports suggest that this regulation is not due to targeting of the α1-subunit to the plasma membrane but is probably a result of a conformational change induced by the β-subunit11,13. Here we report that the β-subunit binds to the cytoplasmic linker between repeats I and II of the dihydropyridine-sensitive α1-subunits from skeletal (α1S) and cardiac muscles (α1C-a), and also with the more distantly related neuronal α1A and ω-conotoxin GVIA-sensitive aα1B-subunits. Sequence analysis of the β-subunit binding site identifies a conserved motif (QQ-E--L-GY--WI---E) positioned 24 amino acids from the IS6 transmem-brane domain in each α1-subunit. Mutations within this motif reduce the stimulation of peak currents by the β-subunit and alter inactivation kinetics and voltage-dependence of activation. Conser-vation of the β-subunit binding motif in these functionally distinct calcium channels suggests a critical role for the I-II cytoplasmic linker of the α1-subunit in channel modulation by the β-subunit.
TL;DR: The data can be used to determine carbon, nitrogen, protein, and Chl a estimates from field material that has been fixed with Lugol’s iodine, observed live, optically measured, or Coulter Counter measured; however, the variability in published data suggests that any of these estimates will have a large potential error.
Abstract: The size of 30 small (2-60 pm) phytoplankton species was examined with a microscope and a Coulter Counter before and after fixation. Acid Lugol’s iodine caused cells to shrink immediately. The shrinkage effect was constant for concentrations of l-10% Lugol’s iodine (in seawater). For optically measured cells fixed in 2% Lugol’s iodine, volume of live cells = 1.33 x (volume of fixed cells). Coulter Counter and optically measured volumes did not agree. For live cells, optical cell volume = 1.24-2.04 x (Coulter Counter determined volume); this difference is likely due to inaccurate volume measurements of nonspherical cells by the Coulter Counter and by inaccurate microscopy resulting from optical distortions (errors of ~0.5 pm in cell dimensions). Cell quota estimates were presented following the relation y = a.x?, where x = optically measured cell volume (pm3), y = any cell constituent (pg cell-‘), and a and b are constants. The constants a and b were 0.109 and 0.99 1 for carbon, 0.0172 and 1.023 for nitrogen, 0.043 and 1.058 for protein, and 0.00428 and 0.9 17 for Chl a. Our relation of carbon to volume differs from other literature values, in which there is no consensus. Our data can be used to determine carbon, nitrogen, protein, and Chl a estimates from field material that has been fixed with Lugol’s iodine, observed live, optically measured, or Coulter Counter measured; however, the variability in published data suggests that any of these estimates will have a large potential error.
TL;DR: CAG trinucleotide expansion is the molecular basis of Huntington's disease worldwide and is a highly sensitive and specific marker for inheritance of the disease mutation.
Abstract: Background Huntington's disease is associated with an expanded sequence of CAG repeats in a gene on chromosome 4p16.3. However, neither the sensitivity of expanded CAG repeats in affected persons of different ethnic origins nor the specificity of such repeats for Huntington's disease as compared with other neuropsychiatric disorders has been determined. Methods We studied 1007 patients with diagnosed Huntington's disease from 565 families and 43 national and ethnic groups. In addition, the length of the CAG repeat was determined in 113 control subjects with a family history of Alzheimer's disease (44 patients), schizophrenia (39), major depression (16), senile chorea (5), benign hereditary chorea (5), neuroacanthocytosis (2), and dentatorubropallidoluysian atrophy (2). The number of CAG repeats was also assessed in 1595 control chromosomes, with the size of adjacent polymorphic CCG trinucleotide repeats taken into account. Results Of 1007 patients with signs and symptoms compatible with a diagnosis of Hun...
TL;DR: One hundred and twenty men referred for treatment for wife assault and forty demographic controls completed self-report questionnaires assessing attachment patterns, anger, jealousy, Borderline Personality Organization, and trauma symptoms.
Abstract: One hundred and twenty men referred for treatment for wife assault and forty demographic controls completed self-report questionnaires assessing attachment patterns, anger, jealousy, Borderline Personality Organization, and trauma symptoms. This constellation, with the exception of attachment, has been found to represent a profile related significantly to the frequency of both verbal and physical abuse. In the present study, attachment was found to correlate significantly with these other measures. A measure of secure attachment correlated significantly, but negatively, with the constellation measures. A measure of fearful attachment correlated significantly and positively. A preoccupied attachment pattern correlated with the other measures less strongly than did the fearful measure. A dismissing measure was not correlated with any constellation measures. The role of attachment anger is discussed; it is suggested that fearful attachment could also be described as angry attachment. The concept of intimacy anger is introduced from early studies in attachment and applied to the explanation of assaultiveness in adult relationships.
TL;DR: A reduced contribution of fatty acid oxidation to energy production in hypertrophied rat hearts is accompanied by a compensatory increase in glycolysis during low work conditions.
Abstract: The contribution of glycolysis and oxidative metabolism to ATP production was determined in isolated working hypertrophied hearts perfused with Krebs-Henseleit buffer containing 3% albumin, 0.4 mM ...
TL;DR: This study used immunohistochemical techniques to characterize and compare the morphological features and distribution in macaque monkey prefrontal cortex of local circuit neurons that contain each of the calretinin, calbindin, and parvalbumin proteins.
Abstract: In the cerebral cortex, local circuit neurons provide critical inhibitory control over the activity of pyramidal neurons, the major class of excitatory efferent cortical cells. The calciumbinding proteins, calretinin, calbindin, and parvalbumin, are expressed in a variety of cortical local circuit neurons. However, in the primate prefrontal cortex, relatively little is known, especially with regard to calretinin, about the specific classes or distribution of local circuit neurons that contain these calcium-binding proteins. In this study, we used immunohistochemical techniques to characterize and compare the morphological features and distribution in macaque monkey prefrontal cortex of local circuit neurons that contain each of these calcium-binding proteins.
On the basis of the axonal features of the labeled neurons, and correlations with previous Golgi studies, calretinin appeared to be present in double-bouquet neurons, calbindin in neurogliaform neurons and Martinotti cells, and parvalbumin in chandelier and wide arbor (basket) neurons. Calretinin was also found in other cell populations, such as a distinctive group of large neurons in the infragranular layers, but it was not possible to assign these neurons to a known cell class. In addition, although the animals studied were adults, immunoreactivity for both calretinin and calbindin was found in Cajal-Retzius neurons of layer I. Dual labeling studies confirmed that with the exception of the Cajal-Retzius neurons, each calcium-binding protein was expressed in separate populations of prefrontal cortical neurons.
Comparisons of the laminar distributions of the labeled neurons also indicated that these calcium-binding proteins were segregated into discrete neuronal populations. Calretinin-positive neurons were present in greatest density in deep layer I and layer II, calbindin-immuno-reactive cells were most dense in layers II-superficial III, and parvalbumin-containing neurons were present in greatest density in the middle cortical layers. In addition, the relative density of calretinin-labeled neurons was approximately twice that of the calbindin- and parvalbumin-positive neurons. However, within each group of labeled neurons, their laminar distribution and relative density did not differ substantially across regions of the prefrontal cortex.
These findings demonstrate that calretinin, calbindin, and parvalbumin are markers of separate populations of local circuit neurons in monkey prefrontal cortex, and that they may be useful tools in unraveling the intrinsic inhibitory circuitry of the primate prefrontal cortex in both normal and disease states.
TL;DR: Disproportionately severe competition between similar phenotypes indicates frequency-dependent selection, verifying a crucial element of theory of competition and character divergence and resolving outstanding debates on the ecological causes of diversification and the evolutionary consequences of competitive interactions.
Abstract: Interspecific competition driving divergence in adaptive radiation has not previously been tested experimentally. Natural selection on a morphologically variable species of stickleback fish was contrasted in the presence and absence of a close relative. Selection was nondirectional when the target species was alone, whereas addition of the second species favored individuals most different from it morphologically and ecologically. Disproportionately severe competition between similar phenotypes indicates frequency-dependent selection, verifying a crucial element of theory of competition and character divergence. The findings help resolve outstanding debates on the ecological causes of diversification and the evolutionary consequences of competitive interactions.
TL;DR: In this article, the authors propose a method to identify the root cause of a problem.Abbreviations: [2]... ].., [3]
TL;DR: There are similarities between PD and manganism, notably the presence of generalized bradykinesia and widespread rigidity and the following dissimilarities in manganistan: (a) less-frequent resting tremor, (b) more frequent dystonia, and (c) a particular propensity to fall backward.
Abstract: From the comparison we have made between PD and manganism, we draw the following conclusions: 1. There are similarities between PD and manganism, notably the presence of (a) generalized bradykinesia and (b) widespread rigidity. 2. There are also dissimilarities between PD and manganism, notably the following in manganism: (a) less-frequent resting tremor, (b) more frequent dystonia, (c) a particular propensity to fall backward, (d) failure to achieve a sustained therapeutic response to levodopa, and (e) failure to detect a reduction in fluorodopa uptake by PET. Further studies are likely to yield more discriminants between PD and manganism. For example, PET with raclopride may be useful in early cases of manganism, and MRI may be helpful in patients with advanced manganism.
TL;DR: A study of aldoses and amino acids in samples collected from a variety of marine depositional environ-ments and representing widely different stages of alteration was conducted in this paper.
Abstract: THE extent of degradation of natural organic mixtures largely determines their utility as records of depositional history, and their potential to act as nutritional substrates and fossil fuel sources. The degree of decomposition is usually inferred from the physical setting of the deposits1 or from bulk chemical composition2, but in both these cases the interpretation can be obscured by several factors3. We report here a study of aldoses and amino acids in samples collected from a variety of marine depositional environ-ments and representing widely different stages of alteration. We identify consistent trends in three compositional characteristics: the percentage of organic carbon in the form of aldoses and protein amino acids, the percentage of total nitrogen present as protein amino acids, and the percentage of total amino acids present as β-alanine and γ-aminobutyric acid. Each of these parameters is sensitive to a different stage of alteration, and they appear to be uncompromised by source variations. Applied together, they offer concordant information on the relative diagenetic stage and reaction potential of natural organic mixtures under both aerobic and anaerobic depositional conditions.
TL;DR: It is hypothesized that the nonmotile phenotype may provide P. aeruginosa a survival advantage in chronic CF infection by enabling it to resist phagocytosis and conserve energy.
Abstract: Although Pseudomonas aeruginosa chronically colonizes most older patients with cystic fibrosis (CF), bacterial features responsible for its persistence are understood poorly. We observed that many P. aeruginosa isolates from chronically colonized patients were nonmotile and resistant to phagocytosis by macrophages. P. aeruginosa isolates were collected from 20 CF patients for up to 10 years. Isolates from early colonization were highly motile and expressed both flagellin and pilin. However, many isolates from chronically colonized patients lacked flagellin expression and were nonmotile; a total of 1,030 P. aeruginosa CF isolates were examined, of which 39% were nonmotile. Moreover, sequential isolates recovered from several of the CF patients were consistently nonmotile for up to 10 years. Lack of motility was rare among environmental isolates (1.4%) and other clinical isolates (3.7%) of P. aeruginosa examined. Partial complementation of motility in nonmotile P. aeruginosa isolates was achieved by introduction of extra copies of the rpoN locus carried on plasmid pPT212, indicating that the alternate sigma factor, RpoN, may be involved in the coordinate regulation of virulence factors during CF infection. We hypothesize that the nonmotile phenotype may provide P. aeruginosa a survival advantage in chronic CF infection by enabling it to resist phagocytosis and conserve energy.
TL;DR: Although treatment was not associated with any improvement in symptoms, ursodeoxycholic acid therapy caused the bilirubin to fall significantly within the first 3 mo of therapy (p<0.001), which led to an improvement in serum markers of cholestasis.
TL;DR: In this article, vertical concentration profiles of the dissolved and suspended particulate phases were determined for a suite of reactive trace metals, Al, Fe, Mn, Zn, and Cd, during summertime at a station in the center of the North Pacific gyre.
TL;DR: In this article, the authors analysed the CAG expansion in different tissues from 12 affected individuals and found that all tissues examined were found to display some repeat mosaicism, with the greatest levels detected in brain and sperm.
Abstract: Huntington disease is associated with an unstable and expanded (CAG) trinucleotide repeat. We have analysed the CAG expansion in different tissues from 12 affected individuals. All tissues examined were found to display some repeat mosaicism, with the greatest levels detected in brain and sperm. Regions within the brain showing most obvious neuropathology, such as the basal ganglia and the cerebral cortex, displayed the greatest mosaicism, whereas the cerebellar cortex, which is seldom involved, displayed the lowest degree of CAG instability. In two cases of childhood onset disease we detected differences of 8 and 13 trinucleotides between the cerebellum and other regions of the brain. Our results provide evidence for tissue specific instability of the CAG repeat, with the largest CAG repeat lengths in affected regions of the brain.
TL;DR: It is reported that song sparrows that survived a severe population bottleneck were a non-random subset of the pre-crash population with respect to inbreeding, and that natural selection favoured outbred individuals, suggesting that inbreeding depression was expressed in the face of an environmental challenge.
Abstract: The genetic and demographic consequences of population subdivision have received considerable attention from conservation biologists. In particular, losses of genetic variability and reduced viability and fecundity due to inbreeding (inbreeding depression) are of concern. Studies of domestic, laboratory and zoo populations have shown inbreeding depression in a variety of traits related to fitness. Consequently, inbreeding depression is widely accepted as a fact. Recently, however, the relative impact of inbreeding on the viability of natural populations has been questioned. Work on the cheetah (Acinonyx jubatus), for example, has emphasized the overwhelming importance of environmental factors on mortality in the wild. Here we report that song sparrows (Melospiza melodia) that survived a severe population bottleneck were a non-random subset of the pre-crash population with respect to inbreeding, and that natural selection favoured outbred individuals. Thus, inbreeding depression was expressed in the face of an environmental challenge. Such challenges are also likely to be faced by inbred populations of endangered species. We suggest that environmental and genetic effects on survival may interact and, as a consequence, that their effects on individuals and populations should not be considered independently.
TL;DR: The present finding of a severe DNMS deficit following rhinal cortex damage is consistent with the authors' previous finding that bilateral lesions of the hippocampus and amygdala cause only mild DNMS deficits in rats unless there is also damage to rhinal Cortex.
Abstract: Rats with bilateral lesions of lateral entorhinal cortex and perirhinal cortex were tested on a nonrecurring-items delayed nonmatching-to-sample (DNMS) task resembling the one that is commonly used to study object recognition in monkeys. The rats were tested at retention delays of 4 s, 15 s, 60 s, 120 s, and 600 s before and after surgery. After surgery, they displayed a delay-dependent deficit: They performed normally at the 4-s delay but were impaired at delays of 15 s or longer. The addition of bilateral amygdala lesions did not increase their DNMS deficits. The present finding of a severe DNMS deficit following rhinal cortex damage is consistent with the authors' previous finding that bilateral lesions of the hippocampus and amygdala cause only mild DNMS deficits in rats unless there is also damage to rhinal cortex (D.G. Mumby, E.R. Wood, & J.P.J. Pinel, 1992). These findings add to accumulating evidence that the rhinal cortex, but not the amygdala, plays a critical role in object recognition.