Showing papers by "University of California, Davis published in 1991"

Identification of markers linked to disease-resistance genes by bulked segregant analysis: a rapid method to detect markers in specific genomic regions by using segregating populations.

Abstract: We developed bulked segregant analysis as a method for rapidly identifying markers linked to any specific gene or genomic region. Two bulked DNA samples are generated from a segregating population from a single cross. Each pool, or bulk, contains individuals that are identical for a particular trait or genomic region but arbitrary at all unlinked regions. The two bulks are therefore genetically dissimilar in the selected region but seemingly heterozygous at all other regions. The two bulks can be made for any genomic region and from any segregating population. The bulks are screened for differences using restriction fragment length polymorphism probes or random amplified polymorphic DNA primers. We have used bulked segregant analysis to identify three random amplified polymorphic DNA markers in lettuce linked to a gene for resistance to downy mildew. We showed that markers can be reliably identified in a 25-centimorgan window on either side of the targeted locus. Bulked segregant analysis has several advantages over the use of near-isogenic lines to identify markers in specific regions of the genome. Genetic walking will be possible by multiple rounds of bulked segregation analysis; each new pair of bulks will differ at a locus identified in the previous round of analysis. This approach will have widespread application both in those species where selfing is possible and in those that are obligatorily outbreeding.

Effect of Oral Milrinone on Mortality in Severe Chronic Heart Failure

Abstract: Background. Milrinone, a phosphodiesterase inhibitor, enhances cardiac contractility by increasing intracellular levels of cyclic AMP, but the long-term effect of this type of positive inotropic agent on the survival of patients with chronic heart failure has not been determined. Methods. We randomly assigned 1088 patients with severe chronic heart failure (New York Heart Association class III or IV) and advanced left ventricular dysfunction to double-blind treatment with 40 mg of oral milrinone daily (561 patients) or placebo (527 patients). In addition, all patients received conventional therapy with digoxin, diuretics, and a converting-enzyme inhibitor throughout the trial. The median period of follow-up was 6.1 months (range, 1 day to 20 months). Results. As compared with placebo, milrinone therapy was associated with a 28 percent increase in mortality from all causes (95 percent confidence interval, 1 to 61 percent; P = 0.038) and a 34 percent increase in cardiovascular mortality (95 percent...

Statistical Efficiency of Double-Bounded Dichotomous Choice Contingent Valuation

Abstract: The statistical efficiency of conventional dichotomous choice contingent valuation surveys can be improved by asking each respondent a second dichotomous choice question which depends on the response to the first question—if the first response is "yes," the second bid is some amount greater than the first bid; while, if the first response is "no," the second bid is some amount smaller. This "double-bounded" approach is shown to be asymptotically more efficient than the conventional, "singlebounded" approach. Using data from a survey of Californians regarding their willingness to pay for wetlands in the San Joaquin Valley, we show that, in a finite sample, the gain in efficiency can be very substantial.

Treatment of gram-negative bacteremia and septic shock with HA-1A human monoclonal antibody against endotoxin. A randomized, double-blind, placebo-controlled trial. The HA-1A Sepsis Study Group.

Abstract: Background HA-1A is a human monoclonal IgM antibody that binds specifically to the lipid A domain of endotoxin and prevents death in laboratory animals with gram-negative bacteremia and endotoxemia Methods To evaluate the efficacy and safety of HA-1A, we conducted a randomized, double-blind trial in patients with sepsis and a presumed diagnosis of gram-negative infection The patients received either a single 100-mg intravenous dose of HA-1A(in 35 g of albumin) or placebo (35 g of albumin) Other interventions, including the administration of antibiotics and fluids, were not affected by the study protocol Results Of 543 patients with sepsis who were treated, 200 (37 percent) had gram-negative bacteremia as proved by blood culture For the patients with gram-negative bacteremia followed to death or day 28, there were 45 deaths among the 92 recipients of placebo (49 percent) and 32 deaths among the 105 recipients of HA-1A (30 percent; P = 0014) For the patients with gram-negative bacteremia and sho

Scenarios and policy aggregation in optimization under uncertainty

Abstract: A common approach in coping with multiperiod optimization problems under uncertainty where statistical information is not really enough to support a stochastic programming model, has been to set up and analyze a number of scenarios. The aim then is to identify trends and essential features on which a robust decision policy can be based. This paper develops for the first time a rigorous algorithmic procedure for determining such a policy in response to any weighting of the scenarios. The scenarios are bundled at various levels to reflect the availability of information, and iterative adjustments are made to the decision policy to adapt to this structure and remove the dependence on hindsight.

The CRC Materials Science And Engineering Handbook

Abstract: TRADITIONAL MATERIALS Metals Physical Properties Chemical Properties Ceramics Physical Properties Chemical Properties Glasses Physical Properties Chemical Properties Polymers Physical Properties Chemical Properties Composites Physical Properties Chemical Properties Semiconductors Physical Properties Chemical Properties ADVANCED MATERIALS Low-Dimensional Carbons and Two-Dimensional Nanomaterials Physical Properties Chemical Properties MAX Phases Physical Properties Chemical Properties References Amorphous Metals Physical Properties References

Rapid In Situ Assay for Indoleacetic Acid Production by Bacteria Immobilized on a Nitrocellulose Membrane

Abstract: We have developed a new assay that differentiates between indoleacetic acid (IAA)-producing and -nonproducing bacteria on a colony plate lift. Medium supplemented with 5 mM L-tryptophan is inoculated with isolates of interest, overlaid with a nitrocellulose membrane, and then incubated until bacterial colonies reach 1 to 2 mm in diameter. The membrane is removed to a filter paper saturated with Salkowski reagent and incubated until distinct red haloes form around the colonies. The colorimetric reaction to IAA is limited to a region immediately surrounding each colony, is specific to isolates producing IAA, occurs within 1 h after the membrane is placed in the reagent, and is sensitive to as little as 50 pmol of IAA in a 2-mm2 spot. We have used this assay for quantifying epiphytic and endophytic populations of IAA-producing isolates of Pseudomonas syringae subsp. savastanoi and for detecting IAA-producing colonies of other pseudomonads and Erwinia herbicola. The assay provides a rapid and convenient method to screen large numbers of bacteria. Images

Southwest U.S.-East Antarctic (SWEAT) connection: A hypothesis

Abstract: A hypothesis for a late Precambrian fit of western North America with the Australia-Antarctic shield region permits the extension of many features through Antarctica and into other parts of Gondwana. Specifically, the Grenville orogen may extend around the coast of East Antarctica into India and Australia. The Wopmay orogen of northwest Canada may extend through eastern Australia into Antarctica and thence beneath the ice to connect with the Yavapai-Mazatzal orogens of the southwestern United States. The ophiolitic belt of the latter may extend into East Antarctica. Counterparts of the Precambrian-Paleozoic sedimentary rocks along the U.S. Cordilleran miogeocline may be present in the Transantarctic Mountains. Orogenic belt boundaries provide useful piercing points for Precambrian continental reconstructions. The model implies that Gondwana and Laurentia rifted away from each other on one margin and collided some 300 m.y. later on their opposite margins to form the Appalachians.

Races of common bean (Phaseolus vulgaris, Fabaceae)

Abstract: Evidence for genetic diversity in cultivated common bean (Phaseolus vulgaris) is reviewed. Multivariate statistical analyses of morphological, agronomic, and molecular data, as well as other available information on Latin American landraces representing various geographical and ecological regions of their primary centers of domestications in the Americas, reveal the existence of two major groups of germplasm: Middle American and Andean South American, which could be further divided into six races. Three races originated in Middle America (races Durango, Jalisco, and Mesoamerica) and three in Andean South America (races Chile, Nueva Granada, and Peru). Their distinctive characteristics and their relationships with previously reported gene pools are discussed.

Intraspecific Variation in the Social Systems of Wild Vertebrates

Abstract: 1. As wild vertebrates are increasingly studied in more than one area or at more than one time instraspecific variation in social systems (IVSS) is increasingly observed. Intraspecific variation has been observed in a number of social systems. Individuals within a single species may be alone or in groups. Their spacing system may be territoriality, coloniality, lekking, dominance or despotism. They may breed monogamously, polyandrously, polygynously or promiscuously. Either both parents or a single parent may care for the young. The parents may or may not have helpers. Parents may or may not pool their young and care for them communally. 2. The evidence so far suggests that most species manifest one of two alternative systems of the same general type, i.e. one of two mating systems or parental care systems. This suggests that there are constraints on their flexibility. These constraints probably include the psychological complexity of the shift from one alternative to another, the compatibility of a particular system with other aspects of the species' natural history, and the species' phylogenetic history. 3. Several ecological variables have so far been identified as correlates of alternative social systems within a species. These variables are generally those currently considered important in interspecific socioecological analysis: differences in 1) the distribution and abundance of food, 2) the level of competition for food, 3) the level and kind of predator pressure, 4) the level of population density and 5) habitat saturation. 4. Alternative social systems are usually viewed as adaptive responses to the costs and benefits of the observed social system compared to alternative social systems. In this respect, IVSS is treated as intraspecific socioecology. 5. Intraspecific socioecology differs profoundly from interspecific socioecology in the approach taken in accounting for observed social systems. Species differences are typically assumed to be caused by genetic differences resulting from distinct natural selection histories in the populations under consideration. IVSS, on the other hand, often involves facultative switching between alternatives that are clearly not traceable to genetic differences. IVSS may be produced by a number of proximate mechanisms. Nutritional state, hormone levels and particular experiences can all predispose animals to different degrees of aggressivity, which in turn may influence the form of social system that emerges from their interactions. Different experiential histories may make one animal inclined to be a member of a group, and another inclined to be solitary. A high level of one kind of social activity may preclude engaging in another. For example, a territorial male under high intruder pressure may be too busy defending space to give paternal care. 6. Progress in the description and interpretation of IVSS will enrich animal behavior as a discipline. In addition, the ability to predict, and possibly even influence, rapid changes in social systems may contribute substantially to conservation strategies.

Rapid spread of an inherited incompatibility factor in California Drosophila.

Abstract: IN Drosophila simulans in California, an inherited cytoplasmic incompatibility factor reduces egg hatch when infected males mate with uninfected females1–7. The infection is spreading at a rate of more than 100km per year; populations in which the infection was rare have become almost completely infected within three years. Analyses of the spread using estimates of selection in the field suggest dispersal distances far higher than those found by direct observation of flies. Hence, occasional long-distance dispersal, possibly coupled with local extinction and recolonization, may be important to the dynamics. Incompatibility factors that can readily spread through natural populations may be useful for population manipulation and important as a post-mating isolating mechanism.

Toward Better Theories of the Policy Process

Abstract: Any theory of the manner in which governmental policies get formulated and implemented, as well as the effects of those actions on the world, requires an understanding of the behavior of major types of governmental institutions (legislatures, courts, administrative agencies, chief executives), as well as the behavior of interest groups, the general public, and the media. The dominant paradigm of the policy process, the stages heuristic popularized by Jones (1970), Anderson (1975), and Peters (1986), has outlived its usefulness and must be replaced, in large part because it is not a causal theory. In the course of their empirical work, policy scholars have highlighted a number of phenomena that need to be incorporated into theories of the policy process. The development of such theories requires an integration ‘of both political scientists’ knowledge of specific institutions and behavior and policy scholars' attention to policy communities, substantive policy information, etc.Innovations by Policy Scholars in Understanding the Policy ProcessAt least since World War II, most political scientists have tended to focus on either a specific type of institution (legislatures, the presidency, courts, interest groups, administrative agencies, local governments, political parties) or on specific types of political behavior outside those institutions (public opinion, voting, political socialization). These have become the standard subfields within the discipline.In contrast, scholars interested in public policy have not been able to stay within these subfields because the policy process spans all of them. In the course of empirical work, policy scholars have highlighted a number of phenomena often neglected by political scientists without a policy focus:a) The importance of policy communities/networks/subsystems involving actors from numerous public and private institutions and from multiple levels of government;b) The importance of substantive policy information;c) The critical role of policy elites vis-a-vis the general public;d) The desirability of longitudinal studies of a decade or more;e) Differences in political behavior across policy types.

Prospective evaluation of arthroscopically assisted anterior cruciate ligament reconstruction Patellar tendon versus semitendinosus and gracilis tendons

Abstract: Eighty consecutive patients with chronic laxity due to a torn ACL underwent arthroscopically assisted reconstruction with either autogenous patellar tendon or doubled semitendinosus and gracilis tendons. Reconstructions were performed on a one-to-one alternating basis. Preoperatively, no significant differences between the two groups were noted with respect to age, sex, level of activity, and degree of laxity (chi square analysis). A standard rehabilitation regimen was used for all patients after surgery including immediate passive knee extension, early stationary cycling, protected weightbearing for 6 weeks, avoidance of resisted terminal knee extension until 6 months, and return to activity at 10 to 12 months postoperatively. Seventy-two patients were evaluated at a minimum of 24 months postoperatively (range, 24 to 40 months). No significant differences were noted between groups with respect to subjective complaints, functional level, or objective laxity evaluation, including KT-1000 measurements. Seventeen of 72 patients (24%) experienced anterior knee pain after ACL reconstruction. Overall, 46 of 72 patients (64%) returned to their preinjury level of activity. Mean KT-1000 scores were 1.6 +/- 1.4 mm for the patellar tendon group and 1.9 +/- 1.3 mm for the semitendinosus and gracilis tendons group. This study did find a statistically significant weakness in peak hamstrings torque at 60 deg/sec when reconstruction was performed with double-looped semitendinosus and gracilis tendons.

Climate change and the evolution of C4 photosynthesis

Abstract: Plants assimilate carbon by one of three photosynthetic pathways, commonly called the C 3 , C 4 , and CAM pathways The C 4 photosynthetic pathway, found only among the angiosperms, represents a modification of C 3 metabolism that is most effective at low concentrations of CO 2 Today, C 4 plants are most common in hot, open ecosystems, and it is commonly felt that they evolved under these conditions However, high light and high temperature, by themselves, are not sufficient to favor the evolution of C 4 photosynthesis at atmospheric CO 2 levels significantly above the current ambient values A review of evidence suggests that C 4 plants evolved in response to a reduction in atmospheric CO 2 levels that began during the Cretaceous and continued until the Miocene

The relationship of physician medical interview style to patient satisfaction.

Abstract: The results of previous studies on the relationship between patient satisfaction and specific interviewing behaviors have been difficult to generalize because most studies have examined small samples of patients at one clinical location and have used initial or acute care visits where the patient and physician did not have an established relationship. The present collaborative study of medical interviewing provided an opportunity to collect interviews from 550 return visits to 127 different physicians at 11 sites across the country. Tape recordings were analyzed using the Roter Interaction Analysis System and post- visit satisfaction questionnaires were administered to patients. A number of significant relationships were found between communication during the visit and the various dimensions of patient satisfaction. Physician question asking about biomedical topics (both open- and closed-ended questions) was negatively related to patient satisfaction; however physician question asking about psychosocial topics was positively related. Physician counseling for psychosocial issues was also positively related to patient satisfaction. Similarly patient talk about biomedical topics was negatively related to satisfaction while patient talk regarding psychosocial topics was positively related. Furthermore patients were less satisfied when physicians dominated the interview by talking more or when the emotional tone was characterized by physician dominance. The findings suggest that patients are most satisfied by interviews that encourage them to talk about psychosocial issues in an atmosphere that is characterized by the absence of physician domination. (authors)

Review. Recent advances in lipid oxidation

Abstract: In a major pathway of the autoxidation of methyl linolenate, peroxyl radicals of the internal hydroperoxides undergo rapid 1,3-tyclisation to form hydroperoxyepidioxides. Because linolenate hydroperoxides are relatively unstable, free radical antioxidants are much less effective in linolenate oils than in linoleate oils. Tocopherols and carotenoids effectively inhibit photosensitised oxidation of vegetable oils. Direct gas chromatographic analyses of malonaldehyde do not correlate with the TBA test. Model fluorescence studies indicate that malonaldehyde may not be so important in crosslinking with DNA. In contrast to oxidised methyl linoleate, oxidised trilinolenin does not form dimers. Although trilinolein oxidises with no preference between the 1(3)-and 2-triglyceride positions, the n-3 double bond of trilinolenin oxidises more in the 1(3)- than in the 2-position. Synthetic triglycerides oxidise in the following decreasing relative rates: LnLnL, LnLLn, LLnL, LLLn (Ln = linolenic and L = linoleic). To estimate the flavour impact of volatile oxidation products their relative threshold values must be considered together with their relative concentration in a given fat.

Gas phase oxidants of cigarette smoke induce lipid peroxidation and changes in lipoprotein properties in human blood plasma. Protective effects of ascorbic acid.

Abstract: Cigarette smoke (CS) is known to contain a large number of oxidants. In order to assess the oxidative effects of CS on biological fluids, we exposed human blood plasma to filtered (gas phase) and unfiltered (whole) CS, and determined the rate of utilization of endogenous antioxidants in relation to the appearance of lipid hydroperoxides. Lipid peroxidation was measured with a specific and sensitive assay that can detect lipid hydroperoxides at plasma levels as low as 10 nM. We found that exposure of plasma to the gas phase of CS, but not to whole CS, induces lipid peroxidation once endogenous ascorbic acid has been oxidized completely. In addition, CS exposure caused oxidation of plasma protein thiols and albumin-bound bilirubin, whereas uric acid and alpha-tocopherol were not consumed at significant rates. In plasma exposed to the gas phase of CS, low-density lipoprotein exhibited slightly increased electrophoretic mobility, but there was no apparent degradation of apolipoprotein B. Our results support the concept of an increased vitamin C utilization in smokers, and suggest that lipid peroxidation induced by oxidants present in the gas phase of CS leads to potentially atherogenic changes in lipoproteins.

Survey of mycosporine-like amino acid compounds in Antarctic marine organisms: Potential protection from ultraviolet exposure

Abstract: To investigate the natural defenses of Antarctic marine organisms against exposure to ultraviolet (UV) radiation (280 to 320 nm), 57 species (1 fish, 48 invertebrates, and 8 algae) were collected during austral spring 1988 in the vicinity of Palmer Station (Anvers Island, Antarctic Peninsula) and were analyzed for the presence of mycosporine-like amino acids (MAAs), compounds that absorb UV radiation and may provide shielding from these biologically hazardous wavelengths. Nearly 90% of the 57 species examined contained MAAs, and eight specific MAA compounds were identified. Seven of these (palythine, porphyra-334, shinorine, mycosporineglycine, palythene, asterina-330, and palythinol) have been observed previously in marine organisms from temperate and tropical latitudes. A new MAA, mycosporineglycine: valine, was found in the Antarctic fish and in 38 of the invertebrate species examined. This study confirms widespread occurrence of MAAs in Antarctic marine organisms and suggests that these species have some degree of natural biochemical protection from UV exposure.

Efficient algorithms for inferring evolutionary trees

Abstract: In this paper, we examine two related problems of inferring the evolutionary history of n objects, either from present characters of the objects or from several partial estimates of their evolutionary history. The first problem is called the Phylogeny problem, and second is the Tree Compatibility problem. Both of these problems are central in algorithmic approaches to the study of evolution and in other problems of historical reconstruction. In this paper, we show that both of these problems can be solved by graph theoretic methods in linear time, which is time optimal, and which is a significant improvement over existing methods.

Relationship of serum estradiol and progesterone concentrations to the excretion profiles of their major urinary metabolites as measured by enzyme immunoassay and radioimmunoassay.

Abstract: Paired daily blood and urine samples were collected from 10 apparently healthy premenopausal women to compare the hormone profiles of estradiol (E2) and progesterone in serum with those of estrone conjugates (E1Conj) and pregnanediol-3-glucuronide (PdG) in urine. Serum hormones were measured by radioimmunoassay (RIA) kits, whereas the urinary steroid metabolites were assessed by both RIA and enzyme immunoassay (EIA). RIA and EIA values for urinary E1Conj and PdG were not different, and both methods produced urinary profiles that paralleled the profile of the parent steroid in serum. However, the simplicity, flexibility, and economy of EIA will make this method more widely applicable. Mean E1Conj values lagged behind concentrations of serum E2 by one day or less, whereas daily urinary PdG profiles lagged behind serum progesterone by one to two days. Mean urinary profiles of E1Conj were similar whether or not creatinine was used to adjust for urine volume; however, creatinine indexing was beneficial when urinary profiles in individual cycles were compared with changes of serum E2.

Identification of broccoli and cauliflower cultivars with RAPD markers.

Abstract: RAPD (Random Amplified Polymorphic DNA) markers generated by 4 arbitrary 10-mer primers, discriminated 14 broccoli and 12 cauliflower cultivars (Brassica oleracea L.) by banding profiles. The size of the amplified DNA fragments ranged from 300 to 2600 base pairs. Twenty-eight percent of the markers were fixed in both broccoli and cauliflower, whereas 12.5% were specific to either crop. The rest were polymorphic in either or both crops. The markers generated by two and three primers were sufficient to distinguish each of the broccoli and cauliflower cultivars, respectively. The average difference in markers was 14.5 between broccoli and cauliflower markers, 5.8 between two broccoli cultivars and 7.9 between two cauliflower cultivars. Larger differences for each crop were found between cultivars from different seed companies than within the same company. RAPD markers provide a quick and reliable alternative to identify broccoli and cauliflower cultivars.

Personal Strivings, Daily Life Events, and Psychological and Physical Well‐Being

Abstract: Interactional models of life events and personality posit domains of vulnerability within which individuals are most likely to be affected by negative life events. A variation of this model was tested in a study of the separate as well as interactive effects of daily life events and personal strivings on psychological and physical well-being. Subjects listed 15 of their personal strivings,which were later categorized as reflecting either achievement, affiliation, intimacy, or power. For 21 consecutive days, subjects recorded up to eight events that most influenced their moods each day, and completed mood and physical symptom checklists. Power strivings were negatively correlated with well-being. Affiliation strivings were correlated with positive affect. No significant between-subject interactions occurred between strivings and events. However, within-subject analyses revealed several significant effects. Achievement-oriented individuals tended to be affected by good achievement events; similarly, the moods of affiliation- and intimacy-oriented individuals were affected by interpersonal events. Results are interpreted within a transactional framework, and implications for research on personality, life events, and well-being are discussed.