Probabilities of identity-by-descent patterns in sibships when the parents are not genotyped

An assumption-free algorithm has been applied to compute the probabilities of all possible identity-by-descent (IBD) configurations when the parents have not been genotyped. These probabilities can be used to determine the amount of information that a particular sibship will bring to a nonparametric linkage analysis. It is shown that the number of possible configurations can be extremely large even when the markers are closely spaced and are rather polymorphic. Further, it is not always possible to reduce this number to a manageable one simply by consideration of the relative probabilities of the configurations.     

Comparison of sire breed solutions for growth traits adjusted by mean expected progeny differences to a 1993 base

Records on growth traits were obtained from five Midwestern agricultural experiment stations as part of a beef cattle crossbreeding project (NC-196). Records on birth weight (BWT, n =3,490), weaning weight (WWT, n = 3,237), and yearling weight (YWT, n = 1,372) were analyzed within locations and pooled across locations to obtain estimates of breed of sire differences. Solutions for breed of sire differences were adjusted to the common base year of 1993. Then, factors to use with within-breed expected progeny differences (EPD) to obtain across-breed EPD were calculated. These factors were compared with factors obtained from similar analyses of records from the U. S. Meat Animal Research Center (MARC). Progeny of Brahman sires mated to Bos taurus cows were heaviest at birth and among the lightest at weaning. Simmental and Gelbvieh sires produced the heaviest progeny at weaning. Estimates of heritability pooled across locations were .34, .19, and .07 for BWT, WWT, and YWT, respectively. Regression coefficients of progeny performance on EPD of sire were 1.25+/-.09, .98+/-.13, and .62+/-.18 for BWT, WWT, and YWT, respectively. Rankings of breeds of sire generally did not change when adjusted for sire sampling. Rankings were generally similar to those previously reported for MARC data, except for Limousin and Charolais sires, which ranked lower for BWT and WWT at NC-196 locations than at MARC. Adjustment factors used to obtain across-breed EPD were largest for Brahman for BWT and for Gelbvieh for WWT. The data for YWT allow only comparison of Angus with Simmental and of Gelbvieh with Limousin.     

Tests for homogeneity of the risk difference when data are sparse

Test statistics for the homogeneity of the risk difference for a series of 2 x 2 tables when the data are sparse is proposed. A weighted least squares statistic is commonly used to test for equality of the risk difference over the tables; however, when the data are sparse, this statistic can have anticonservative Type I error rates. Simulation is used to compare the proposed test statistics to the weighted least squares statistic. The weighted least squares statistic has the most anticonservative Type I error rates of all the statistics compared. We suggest the use of one of our proposed test statistics instead of the weighted least squares statistic.     

Characterization of Alu repeats that are associated with trinucleotide and tetranucleotide repeat microsatellites

The association of subclasses of Alu repetitive elements with various classes of trinucleotide and tetranucleotide microsatellites was characterized as a first step toward advancing our understanding of the evolution of microsatellite repeats. In addition, information regarding the association of specific classes of microsatellites with families of Alu elements was used to facilitate the development of genetic markers. Sequences containing Alu repeats were eliminated because unique primers could not be designed. Various classes of microsatellites are associated with different classes of Alu repeats. Very abundant and poly(A)-rich microsatellite classes (ATA, AATA) are frequently associated with an evolutionarily older subclass of Alu repeats, AluSx, whereas most of GATA and CA microsatellites are associated with a recent Alu subfamily, AluY. Our observations support all three possible mechanisms for the association of Alu repeats to microsatellites. Primers designed using a set of sequences from a particular microsatellite class showed higher homology with more sequences of that class than probes designed for other classes. We developed an efficient method of prescreening GGAA and ATA microsatellite clones for Alu repeats with probes designed in this study. We also showed that Alu probes labeled in a single reaction (multiplex labeling) could be used efficiently for prescreening of GGAA clones. Sequencing of these prescreened GGAA microsatellites revealed only 5% Alu repeats. Prescreening with primers designed for ATA microsatellite class resulted in the reduction of the loss of markers from approximately 50% to 10%. The new Alu probes that were designed have also proved to be useful in Alu-Alu fingerprinting.     

Robustness and non-parametric procedures are not the only or the safe alternatives to normality.

Data from a simple paired comparison design illustrated that "robustness" arguments and nonparametric procedures do not contradict the need to know what form the distribution of the observations really has. (11 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Use of the nonequivalent control group design when subjects are growing.

Many experimental programs aim to accelerate the growth of individuals on some dimension of interest. Typically, a group exposed to the program is compared with a control group. When it is feasible, random assignment of Ss to the program and control groups assures an unbiased comparison between treatments. Without randomization there may be important differences between groups, in terms of pretreatment characteristics and growth potential. In the nonequivalent control group design, pretest and posttest data on both groups are obtained. Statistical methods are used to adjust posttest comparisons, based mainly on pretest information. A variety of statistical techniques have been proposed, but there is much disagreement among methodologists as to which, if any, are adequate. This article examines the adequacy of these techniques, from an individual growth perspective. The performance of various commonly used methods is examined under alternative assumptions about the nature of growth. It is concluded that statistical adjustments are generally inadequate in the face of nonequivalent growth systems across treatment groups. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Oocyte determination and the origin of polarity in Drosophila: the role of the spindle genes

The two main body axes in Drosophila become polarised as a result of a series of symmetry-breaking steps during oogenesis. Two of the sixteen germline cells in each egg chamber develop as pro-oocytes, and the first asymmetry arises when one of these cells is selected to become the oocyte. Anterior-posterior polarity originates when the oocyte then comes to lie posterior to the nurse cells and signals through the Gurken/Egfr pathway to induce the adjacent follicle cells to adopt a posterior fate. This directs the movement of the germinal vesicle and associated gurken mRNA from the posterior to an anterior corner of the oocyte, where Gurken protein signals for a second time to induce the dorsal follicle cells, thereby polarising the dorsal-ventral axis. Here we describe a group of five genes, the spindle loci, which are required for each of these polarising events. spindle mutants inhibit the induction of both the posterior and dorsal follicle cells by disrupting the localisation and translation of gurken mRNA. Moreover, the oocyte often fails to reach the posterior of mutant egg chambers and differentiates abnormally. Finally, double mutants cause both pro-oocytes to develop as oocytes, by delaying the choice between these two cells. Thus, these mutants reveal a novel link between oocyte selection, oocyte positioning and axis formation in Drosophila, leading us to propose that the spindle genes act in a process that is common to several of these events.     

Exercises: which ones are worth trying, for which patients, and when?

STUDY DESIGN: Criteria-based review. SUMMARY OF BACKGROUND DATA: Reviews based on trials published up to 1990 conclude that the efficacy of exercise therapy in patients with low back pain is questionable. OBJECTIVES: To determine from recently published trials the efficacy of exercises in patients with acute, subacute, or chronic back pain. METHODS: A Medline search for randomized trials concerning exercise therapy in patients with back pain published from 1991 until the first quarter of 1995 was conducted. All studies were given a method score (maximum, 100 points). RESULTS: Eleven randomized trials were included: four in acute back pain, one in subacute, and six in patients with chronic back pain. Three trials had method scores lower than 40 points. For acute back pain, two trials with high method scores (> 50 points) reported no efficacy of flexion or extension exercises; two trials of the McKenzie type of exercises reported positive results but had low method scores. For subacute pain, one trial (> 50 points) reported positive results of exercises with a graded activity program. For chronic back pain, three trials reported positive results with different types of exercises; two trials reported better results with intensive exercising compared with low grade exercising, but after 12 months, this effect had disappeared. In chronic pain, no relation between method score and conclusions could be found. CONCLUSIONS: In acute back pain, exercise therapy is ineffective, whereas in subacute back pain, exercises with a graded activity program, and in chronic back pain, intensive exercising, deserve attention. More research on McKenzie therapy, on exercises with a graded activity program, and on different types of exercising in patients with chronic back pain is necessary.     

Kinetics of plasma fructose and glucose when lactose and fructose are used as energy supplements for neonatal calves

Shortly after birth, plasma glucose and fructose concentrations of the neonate decline and thus leave blood sugar below the homeostatic mode. Two trials were conducted to determine the plasma glucose and fructose kinetics in control and supplemented calves for 108 h after birth. In the short-term trial, six Holstein calves were given 40 g of either fructose, lactose, or water (control) orally at 1 and 96 h after birth. Treatments were administered with a colostrum substitute (Life Boost) at 1 h and whole milk at 96 h. Rectal temperatures and changes in plasma glucose and fructose concentrations were monitored at close intervals for 12 h after supplementation. In the long-term trial, 15 Holstein calves were given 40 g of either lactose, fructose, or water (control) at 1 h after birth and at 12-h intervals for 81 h. Plasma glucose and fructose concentrations were determined before and 4 h after each of the seven feedings. Early postpartal feeding of fructose suppressed plasma glucose (approximately 50%), with a reciprocal rise in plasma fructose. Irrespective of treatment, plasma glucose concentrations did not stabilize (approximately 100 mg/dL) until 17 to 24 h after birth. After 24 h, lactose supplements increased concentrations of plasma glucose 4 h after supplementation (169.7 +/- 8.2 mg/dL), compared with those in calves that did not receive the additional lactose. After 24 h, fructose supplements did not affect plasma glucose, but plasma fructose concentrations increased (82.6 +/- 12.4 mg/dL) 4 h after administration. The response to fructose supplements declined by 11.4 mg x dL(-1) x d(-1). Fructose was not detected in the plasma of control or lactose-treated calves after 17 h after birth. Calves that received fructose supplements had rectal temperatures 8 and 10 h after birth that were higher than those of the other calves. The mechanisms of sugar metabolism change quickly following birth. Oral sugar supplements increase the total plasma sugar concentrations of treated calves.     

Analysis of multiplicative combination rules when the causal variables are measured with error.

Evaluates the validity of the observational method used to test multiplicative combination rules with respect to 2 measurement issues: measurement level (i.e., the effects produced by allowing monotonic transformations of the measures) and measurement error (i.e., the effects produced by using unreliable measures of the causal variables). The evaluation is based on a theoretical distinction between the structural model (the set of equations relating theoretical constructs to each other) and the measurement model (the set of equations relating the theoretical constructs to the observed measures). It is concluded that hierarchical regression analysis is inadequate for determining whether the structural model is additive or multiplicative for 2 reasons: First, an additive structural model may produce multiplicative effects through a nonlinear measurement model. Second, a multiplicative structural model may produce nondetectable multiplicative effects because of multiplicative measurement error. Some alternatives to hierarchical regression analysis are described. (35 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aprotinin and deep hypothermic circulatory arrest: there are no benefits even when appropriate amounts of heparin are given

OBJECTIVE: To evaluate retrospectively the effect of 'high-dose' aprotinin on blood losses, donor blood requirements and morbid events on patients undergoing ascending aorta and/or aortic arch procedures with the employ of deep hypothermic circulatory arrest (HCA). METHODS: During the period 1987-1994, 39 patients underwent a thoracic aorta procedure with the employ of circulatory arrest; of these 18 (46.2%) were operated on during the period 1990-1994 and were given aprotinin intraoperatively following the 'high-dose' protocol (group I), while 21 (53.8%) who underwent surgery during the years 1987-1989, did not receive intraoperative aprotinin and served as historical controls (group II). Twenty-seven (69.2%) patients were male, 18 (46.2%) were operated on on an emergency basis, 15 (38.5%) were acute type A dissections, and two (5.1%) were redo-operations. Circulatory arrest times were not significantly different between the two groups (40 +/- 4 (S.E.) group I vs. 43 +/- 4 min group II, P = 0.62) likewise cardiopulmonary bypass (CPB) times (181 +/- 9 vs. 201 +/- 20 mm, P = 0.74) and the amount of heparin administered (32056 +/- 1435 vs. 31 691 +/- 1935 IU, P = 0.56). RESULTS: Postoperative blood loss was comparable between the two groups (1213 +/- 243 (median 850) group I vs. 1528 +/- 377 (median 880) ml group II, P = 0.87), as well as the number of units of donor blood transfused (9.4 +/- 3.0 (median 6) vs. 9.9 +/- 3.6, (median 5) P = 0.87), and revisions for bleeding (2/18, 11.1% vs. 3/21, 14.3%, P = 0.77). In-hospital mortality rate was not statistically different (5/18, 27.7% group I vs. 6/21, 28.6% group II, P = 0.92). There were no significant differences between the two groups in myocardial infarction (2/18, 11.1% vs. 0/21, 0%, P = 0.21), and postoperative renal failure rates (3/18, 16.7% vs. 2/21, 9.5%, P = 0.65). On the other hand, there was a trend towards an increased incidence of permanent neurological deficit (5/18, 27.7% group I vs. 1/21, 4.8% group II, P = 0.07) and towards a more complicated postoperative course (perioperative renal failure and/or myocardial infarction and/or neurological deficit either transient or permanent) (8/18, 44.4% group I vs. 4/21, 19% group II, P = 0.09) in group I patients. Forward stepwise logistic regression analysis, performed on the whole group of patients, identified chronic obstructive pulmonary disease (P = 0.010, Odds ratio (OR) = 5.7), aprotinin use (P = 0.017, OR = 5.1), and the number of units of blood collected intraoperatively by the cellsaver (P = 0.045, OR = 1.3/unit) as independent predictors of complicated postoperative course in the whole group of patients. CPB time (P = 0.040, OR = 1.032/min), circulatory arrest time (P = 0.053, OR = 1.22/min), and overall donor blood units transfused (P = 0.067, OR = 1.37/unit) emerged as independent risk factors for in-hospital mortality at multivariate analysis. CONCLUSIONS: Even when appropriate amounts of heparin are administered, 'high-dose' aprotinin probably is not an effective blood-sparing drug in deep HCA. Aprotinin should be employed cautiously in this clinical setting because of its possible correlation with an increased rate of postoperative morbid events.     

节能减排保护环境是企业应履行的社会责任更是企业生存和发展的必然要求

节能减排、保护环境是企业应履行的社会责任,更是企业生存发展的必然要求。企业要生存发展,必须做好节能减排和环境保护工作。云南冶金集团股份有限公司一直十分重视节能减排和环保工作,把节能减排和保护环境当作企业生存和发展的重要任务,在生产和经济发展的同时,加强生态环境保护,重视节能减排和绿化建设,在创建绿色企业、保护环境中做大做强云南冶金工业。     

Assembly of T-antigen double hexamers on the simian virus 40 core origin requires only a subset of the available binding sites

Initiation of simian virus 40 (SV40) DNA replication is dependent upon the assembly of two T-antigen (T-ag) hexamers on the SV40 core origin. To further define the oligomerization mechanism, the pentanucleotide requirements for T-ag assembly were investigated. Here, we demonstrate that individual pentanucleotides support hexamer formation, while particular pairs of pentanucleotides suffice for the assembly of T-ag double hexamers. Related studies demonstrate that T-ag double hexamers formed on "active pairs" of pentanucleotides catalyze a set of previously described structural distortions within the core origin. For the four-pentanucleotide-containing wild-type SV40 core origin, footprinting experiments indicate that T-ag double hexamers prefer to bind to pentanucleotides 1 and 3. Collectively, these experiments demonstrate that only two of the four pentanucleotides in the core origin are necessary for T-ag assembly and the induction of structural changes in the core origin. Since all four pentanucleotides in the wild-type origin are necessary for extensive DNA unwinding, we concluded that the second pair of pentanucleotides is required at a step subsequent to the initial assembly process.     

Cooperative breeding and monogamy in prairie voles: influence of the sire and geographical variation

Mammalian monogamy is characterized by pair bonding and a relative absence of sexual dimorphism in body size. Alloparental behaviour is a characteristic of mammalian cooperative breeding systems. Studies of prairie voles, Microtus ochrogaster, from stock captured in a resource-abundant habitat in Illinois have supported the assumption that this species is a monogamous, cooperative breeder, while other studies of prairie voles from a more arid habitat in Kansas have called this assumption into question. We hypothesized that reported differences between these populations represented true intraspecific variation. Patterns of sexual dimorphism in body size, partner preferences and parental contact behaviour were compared in prairie voles from stocks originating in Illinois or Kansas. Both Illinois and Kansas voles showed a strong preference for a familiar partner, which is suggestive of monogamy. Sexual dimorphism in body size was observed in Kansas, but not Illinois voles. Illinois voles displayed significantly higher levels of parental contact behaviour than did voles from Kansas. When animals from Illinois and Kansas were crossed, the expression of parental contact behaviour of the 'hybrid' offspring followed the pattern seen in the population of origin of the sire. Removal of the sire prior to the birth of the litter increased alloparenting in Kansas voles, but removal of the sire was associated with lower levels of alloparenting in Illinois voles. Thus, some traits associated with the social system may show intraspecific variation and can be influenced by the presence or absence of the sire during rearing. Copyright 1998 The Association for the Study of Animal Behaviour. Copyright 1998 The Association for the Study of Animal Behaviour.     

Reasons for staying alive when you are thinking of killing yourself: The Reasons for Living Inventory.

65 adults generated 72 distinct reasons for not committing suicide; these were reduced to 48 by factor analyses performed on 2 additional samples, and the items were arranged into the Reasons for Living Inventory (RFL), which requires a rating of how important each reason would be for living if suicide were contemplated. In addition, factor analyses indicated 6 primary reasons for living: Survival and Coping Beliefs, Responsibility to Family, Child-Related Concerns, Fear of Suicide, Fear of Social Disapproval, and Moral Objections. The RFL was then given to 2 additional samples, 197 Seattle shoppers (mean age 36 yrs) and 175 psychiatric inpatients (mean age 31 yrs). Both samples were divided into several suicidal (ideators and parasuicides) and nonsuicidal groups. Separate multivariate ANOVAs indicated that the RFL differentiated suicidal from nonsuicidal Ss in both samples. In the shopping-center sample, the Fear of Suicide scale further differentiated between previous ideators and previous parasuicides. In the clinical sample, the Child-Related Concerns scales differentiated between current suicide ideators and current parasuicides. In both samples, the Survival and Coping, the Responsibility to Family, and the Child-Related Concerns scales were most useful in differentiating the groups. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Design of experiments to estimate heritability when observations are available on parents and offspring

The design of experiments to estimate heritability when data are available on both parents and offspring and the offspring data have a hierarchical structure is considered. Univariate maximum likelihood (ML) estimation is discussed, and extensions to the multivariate case are outlined. The efficiency of ML estimation is evaluated in cases where simple regression estimators are available. Optimum designs for ML estimation are given when various strategies of selecting and mating are followed. The variance of the heritability estimate can be approximately halved relative to designs in which no selection of parents is done.     

Two Li-Fraumeni syndrome families with novel germline p53 mutations: loss of the wild-type p53 allele in only 50% of tumours

We describe two Li-Fraumeni syndrome families. Family A was remarkable for two early childhood cases of adrenocortical tumours, family B for a high incidence of many characteristic cancers, including a childhood case of choroid plexus tumour. Using direct sequencing, we analysed exons 5-9 of the p53 gene in constitutional DNA of individuals from both families and found two novel germline mutations in exon 5. In family A, we detected a point substitution in codon 138 (GCC to CCC), which resulted in the replacement of the alanine by a proline residue. Family B harboured a single-base pair deletion in codon 178 (CAC to -AC), resulting in a frameshift and premature chain termination. Three out of six tumours examined from both families, a renal cell carcinoma, a rhabdomyosarcoma and a breast cancer, showed loss of heterozygosity and contained only the mutant p53 allele. The remaining three neoplasms, both adrenocortical tumours and the choroid plexus tumour retained heterozygosity. Immunohistochemistry with anti-p53 antibody confirmed accumulation of p53 protein in tumours with loss of heterozygosity, while the remaining tumours were p53 negative. These results support the view that complete loss of activity of the wild-type p53 need not be the initial event in the formation of all tumours in Li-Fraumeni individuals.