Home About us Contact
|
Home About us Contact | ||
|
|
||
Only Weak (only + weak)
Terms modified by Only Weak Selected AbstractsTHE EVOLUTION OF GENETIC CANALIZATION UNDER FLUCTUATING SELECTIONEVOLUTION, Issue 1 2000Tadeusz J. Kawecki Abstract., If the direction of selection changes from generation to generation, the ability to respond to selection is maladaptive: the response to selection in one generation leads to reduced fitness in the next. Because the response is determined by the amount of genetic variance expressed at the phenotypic level, rapidly fluctuating selection should favor modifier genes that reduce the phenotypic effect of alleles segregating at structural loci underlying the trait. Such reduction in phenotypic expression of genetic variation has been named "genetic canalization." I support this argument with a series of two- and multilocus models with alternating linear selection and Gaussian selection with fluctuating optimum. A canalizing modifier gene affects the fitness of its carriers in three ways: (1) it reduces the phenotypic consequences of genetic response to previous selection; (2) it reduces the genetic response to selection, which is manifested as linkage disequilibrium between the modifier and structural loci; and (3) it reduces the phenotypic variance. The first two effects reduce fitness under directional selection sustained for several generations, but improve fitness when the direction of selection has just been reversed. The net effect tends to favor a canalizing modifier under rapidly fluctuating selection regimes (period of eight generations or less). The third effect improves fitness of the modifier allele if the fitness function is convex and reduces it if the function is concave. Under fluctuating Gaussian selection, the population is more likely to experience the concave portion of the fitness function when selection is stronger. Therefore, only weak to moderately strong fluctuating Gaussian selection favors genetic canalization. This paper considerably broadens the conditions that favor genetic canalization, which so far has only been postulated to evolve under long-term stabilizing selection. [source] Validity of the indicator ,death in low-mortality diagnosis-related groups' for measuring patient safety and healthcare quality in hospitalsINTERNAL MEDICINE JOURNAL, Issue 4 2010S. Mihrshahi Abstract The indicator ,death in low-mortality diagnosis-related groups (DRG)' is a patient safety indicator (PSI) that can be derived from routinely collected administrative data sources. It is included in a group of PSI that have been proposed to compare and monitor standards of hospital care in Australia. To summarize the attributes of this indicator as a measure of quality and safety in healthcare and examine issues regarding the development process, definitions and use of the indicator in practice. A structured literature search was conducted using the Ovid Medline database to identify peer-reviewed published literature which used ,death in low-mortality DRG' as a quality/safety indicator. Key quality websites were also searched. The studies were critically appraised using a standardized method. A total of 12 articles was identified which met our search criteria. Most were of low methodological quality because of their retrospective study designs. Only three studies provided evidence that the quality of care gap is higher in ,deaths in low-mortality DRG' than in other cases. Most of the studies reviewed show that there are several limitations of the indicator for assessing patient safety and quality of care. The few studies that have assessed associations with other measures of hospital quality have shown only weak and inconsistent associations. Higher quality, prospective, analytic studies are required before ,death in low-mortality DRG' is used as an indicator of quality and safety in healthcare. Based on current evidence, the most appropriate use is as a screening tool for institutions to quickly and easily identify a manageable number of medical records to investigate in more detail. [source] Monetary policy's effects during the financial crises in Brazil and KoreaINTERNATIONAL JOURNAL OF FINANCE & ECONOMICS, Issue 1 2003Charles Goodhart This paper looks at the effect of monetary policy changes on asset prices in the foreign exchange and equity markets of Brazil and Korea. We were searching for evidence whether monetary policy tightening may have had (adverse) counterproductive effects on such asset markets. In common with other authors we find only weak or sporadic evidence for this hypothesis. Using a theoretical model of financial market imperfections, we show that the failure to find monetary policy effectiveness during a crisis can come about not only because of the endogeneity caused by a ,leaning against the wind' policy reaction but also, independently, if there are large and correlated risk premia in the financial markets in which interest rates and determined. Copyright © 2003 John Wiley & Sons, Ltd. [source] Expression of synapsin and co-localization with serotonin and RFamide-like immunoreactivity in the nervous system of the chordoid larva of Symbion pandora (Cycliophora)INVERTEBRATE BIOLOGY, Issue 1 2010Ricardo Cardoso Neves Abstract. Cycliophora is one of the most recently described metazoan phyla and hitherto includes only two species: Symbion pandora and Symbion americanus. With a very complex life cycle, cycliophorans are regarded as an enigmatic group with an uncertain phylogenetic position, although they are commonly considered lophotrochozoan protostomes. In order to extend the database concerning the distribution of immunoreactive substances in the free-swimming chordoid larva of S. pandora, we investigated synapsin immunoreactivity using fluorescence-coupled antibodies in combination with confocal laserscanning microscopy. Moreover, we analyzed the co-localization patterns of synapsin, serotonin, and RFamide-like immunoreactivity in the chordoid larva by 3D imaging technology based on the confocal microscopy image stacks. Synapsin is expressed in large parts of the bilobed anterior cerebral ganglion including anterior and dorsal projections. Two pairs of ventral neurites run longitudinally into the larval body of which the inner pair shows only weak, scattered synapsin immunoreactivity. In addition, a lateral synapsin immunoreactive projection emerges posteriorly from each ventral longitudinal axon. Double immunostaining shows co-localization of synapsin and serotonin in the cerebral ganglion, the outer and the inner ventral neurites, and the anterior projections. Synapsin and RFamide-like immunoreactivity co-occur in the cerebral ganglion, the outer ventral neurites, and the dorsal projections. Accordingly, the cerebral ganglion and the outer ventral neurites are the only neural structures that co-express the two neurotransmitters and synapsin. The overall neuroanatomical condition of the cycliophoran chordoid larva resembles much more the situation of adult rather than larval life cycle stages of a number of spiralian taxa. [source] Principles of Peripheral Blood Mononuclear Cell Apheresis in a Preclinical Canine Model of Hematopoietic Cell TransplantationJOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 1 2008M. Lupu Background: Preclinical studies of peripheral blood mononuclear cell (PBMC) transplantation conducted in a well-established canine hematopoietic cell transplantation (HCT) model have been successfully translated to human patients over the past 5 decades. Objective: We retrospectively investigated the safety and feasibility of PBMC apheresis in the canine model of HCT by analyzing apheresis parameters, cell yields, and the impacts of donor-related and apheresis-related variables on collection yields and donor stability. Animals: One hundred and twenty dogs that underwent PBMC aphereses were evaluated. Methods: Aphereses were performed with a COBE Spectra blood separator and a central dual-lumen catheter, with or without recombinant canine granulocyte colony-stimulating factor (rcG-CSF) stem cell mobilization. Results: Aphereses from dogs not given rcG-CSF yielded an average volume of 280 ± 42 mL containing an average of 15,086 ± 9,834 leukocytes/mL. Aphereses from dogs given rcG-CSF yielded an average volume of 261 ± 55 mL containing an average of 39,711 ± 24,488 leukocytes/mL. Higher pre-apheresis white blood cell (WBC) counts correlated with higher apheresis WBC yields (R=0.50, P<.0001). The correlations of collection time, inlet volume, and collection flow rate on WBC yields were statistically significant but only weak to moderate in magnitude (R=0.34, P=.0001; R=0.38, P=.0006; R=0.26, P=.002, respectively) as were the correlations of collection time and inlet volume on collection volumes (R=0.30, P=.002; R=0.42, P<.0001, respectively). All dogs recovered promptly after PBMC aphereses and catheter removal, without complications. Conclusions and Clinical Importance: These data may be useful for translating PBMC apheresis technology to the field of veterinary oncology for the treatment of dogs with hematologic malignancies. [source] Monophyletic groups within ,higher land birds', comparison of morphological and molecular dataJOURNAL OF ZOOLOGICAL SYSTEMATICS AND EVOLUTIONARY RESEARCH, Issue 4 2003G. Mayr Abstract The relationships within the ,higher land birds' and putatively related taxa are analysed in a study using 89 morphological characters and DNA sequences of three nuclear, protein-coding genes, c- myc, RAG-1, and myoglobin intron II. Separate analyses of the different data sets and a ,total evidence' analysis in which the data sets of the morphological and molecular analyses were combined are compared. All three analyses support the hitherto disputed sister group relationship between Pici (Ramphastidae, Indicatoridae and Picidae) and Galbulae (Galbulidae and Bucconidae). Previously unrecognized osteological synapomorphies of this clade are presented. All analyses further resulted in monophyly of the taxon [Aegothelidae + (Apodidae/Hemiprocnidae + Trochilidae)]. Analysis of the morphological data and of the combined data set also supported monophyly of the taxon [Strigiformes + (Falconidae + Accipitridae)]. The morphological data further support monophyly of the taxon (Upupidae + Bucerotidae). Other placements in the three analyses received either no or only weak bootstrap support. [source] Reliability and validity of the Leisure Satisfaction Scale (LSS , short form) and the Adolescent Leisure Interest Profile (ALIP)OCCUPATIONAL THERAPY INTERNATIONAL, Issue 2 2002Angela N. Trottier MClSc, OT Reg (Ont) Occupational Therapist Abstract This study aimed to evaluate the reliability and validity of the Leisure Satisfaction Scale (LSS , short form) and the Adolescent Leisure Interest Profile (ALIP). The LSS and the ALIP are instruments that occupational therapists can use to evaluate the leisure activities that clients enjoy. Evaluation of leisure interest and participation will assist in creating goals for therapy to maximize a client's ability to participate in leisure activities. This study examined the test,retest reliability and concurrent validity of the LSS and the ALIP using a sample of 37 adolescents between the ages of 13 and 17 with no known impairments. The assessments were administered individually or in small groups 7 to 17 days apart. Cronbach's alpha was used to determine the internal consistency. Pearson product moment correlations were calculated to examine the test,retest reliability of the 60 subscales and the six question totals of the ALIP, as well as for the 6 subscales and total score of the LSS. Concurrent validity was evaluated between the ,How often?' question of the ALIP and the LSS (short form). Based on the study results, the ALIP and the LSS seem to have good test,retest reliability levels when used with adolescents with no known physical or mental impairments. The concurrent validity between the two instruments was not supported, with many of the scores indicating only weak or no association to each of the subscales, suggesting that the assessments differ in some fundamental way. However, the evidence of some relationships between subscales may indicate some areas where the ALIP and the LSS are similar. Copyright © 2002 Whurr Publishers Ltd. [source] CD97, CD95 and Fas-L clearly discriminate between chronic pancreatitis and pancreatic ductal adenocarcinoma in perioperative evaluation of cryocut sectionsPATHOLOGY INTERNATIONAL, Issue 2 2002Carsten Boltze It is a major problem to distinguish between pancreatitis and pancreatic adenocarcinoma when it comes to the perioperative evaluation of pancreatic cryocut sections. In this respect, pathologists are showing a steadily growing interest in the potential application of apoptotic and dedifferentiation factors as diagnostic and prognostic markers. This study investigated the mRNA and protein expression of CD97, CD95 and Fas-L in snap-frozen material obtained from human pancreatic ductal adenocarcinomas (PDC; n = 50), tissues from pancreatitis (PT; n = 40) and normal pancreatic tissues (PN; n = 36). Reverse transcription,polymerase chain reaction (RT,PCR) analysis revealed that CD97, CD95 and Fas-L mRNA were expressed on a similarly high level in all tissues. In contrast, short time immunohistochemical evaluation showed that the CD95 protein was strongly expressed in PT and PN, but not in PDC. Fas-L protein was expressed strongly in PDC, whereas only weak or no expression was noted in PT or PN. CD97 protein expression was detected only in PT and in poorly differentiated PDC. Our data demonstrate that CD97, CD95 and Fas-L can be used as additional markers to distinguish between pancreatitis and pancreatic duct cell carcinoma in cryocut sections. [source] | |||||||||||||