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Clear Preference (clear + preference)
Selected AbstractsNon-random reassortment in human influenza A virusesINFLUENZA AND OTHER RESPIRATORY VIRUSES, Issue 1 2008Raul Rabadan Background, The influenza A virus has two basic modes of evolution. Because of a high error rate in the process of replication by RNA polymerase, the viral genome drifts via accumulated mutations. The second mode of evolution is termed a shift, which results from the reassortment of the eight segments of this virus. When two different influenza viruses co-infect the same host cell, new virions can be released that contain segments from both parental strains. This type of shift has been the source of at least two of the influenza pandemics in the 20th century (H2N2 in 1957 and H3N2 in 1968). Objectives, The methods to measure these genetic shifts have not yet provided a quantitative answer to questions such as: what is the rate of genetic reassortment during a local epidemic? Are all possible reassortments equally likely or are there preferred patterns? Methods, To answer these questions and provide a quantitative way to measure genetic shifts, a new method for detecting reassortments from nucleotide sequence data was created that does not rely upon phylogenetic analysis. Two different sequence databases were used: human H3N2 viruses isolated in New York State between 1995 and 2006, and human H3N2 viruses isolated in New Zealand between 2000 and 2005. Results, Using this new method, we were able to reproduce all the reassortments found in earlier works, as well as detect, with very high confidence, many reassortments that were not detected by previous authors. We obtain a lower bound on the reassortment rate of 2,3 events per year, and find a clear preference for reassortments involving only one segment, most often hemagglutinin or neuraminidase. At a lower frequency several segments appear to reassort in vivo in defined groups as has been suggested previously in vitro. Conclusions, Our results strongly suggest that the patterns of reassortment in the viral population are not random. Deciphering these patterns can be a useful tool in attempting to understand and predict possible influenza pandemics. [source] Optimal airfoil shapes for low Reynolds number flowsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 4 2009D. N. Srinath Abstract Flow over NACA 0012 airfoil is studied at , = 4, and 12, for Re,500. It is seen that the flow is very sensitive to Re. A continuous adjoint based method is formulated and implemented for the design of airfoils at low Reynolds numbers. The airfoil shape is parametrized with a non-uniform rational B-splines (NURBS). Optimization studies are carried out using different objective functions namely: (1) minimize drag, (2) maximize lift, (3) maximize lift to drag ratio, (4) minimize drag and maximize lift and (5) minimize drag at constant lift. The effect of Reynolds number and definition of the objective function on the optimization process is investigated. Very interesting shapes are discovered at low Re. It is found that, for the range of Re studied, none of the objective functions considered show a clear preference with respect to the maximum lift that can be achieved. The five objective functions result in fairly diverse geometries. With the addition of an inverse constraint on the volume of the airfoil the range of optimal shapes, produced by different objective functions, is smaller. The non-monotonic behavior of the objective functions with respect to the design variables is demonstrated. The effect of the number of design parameters on the optimal shapes is studied. As expected, richer design space leads to geometries with better aerodynamic properties. This study demonstrates the need to consider several objective functions to achieve an optimal design when an algorithm that seeks local optima is used. Copyright © 2008 John Wiley & Sons, Ltd. [source] Comparison of feed preference and digestion of three different commercial diets for cats and ferretsJOURNAL OF ANIMAL PHYSIOLOGY AND NUTRITION, Issue 3-6 2005S. Gy. Summary Diet preference and digestibility experiments were conducted using a total of 10 cats and 10 ferrets. The composition of the three different kinds of dry cat feed was as follows (each data are given in dry matter, DM): (i) normal diet (N): 95.3% DM, 33.7% crude protein (CP), 20.4% ether extract (EE), 37.6% nitrogen-free extract (NFE); (ii) ,light diet' (L): 94.2% DM, 31.6% CP, 10.7% EE, 52.2% NFE; (iii) ,veterinary diet' (D): 94.57% DM, 38.7% CP, 9.6% EE, 47.2% NFE. During the period of the preference test, the average daily dry matter intake (calculated with the mean of the three diets: 94.7% DM) was 98.0, 15.0 and 16.7 g DM in cats and 25.0, 7.3 and 8.1 g DM in ferrets. The preference rates of the three different diets, expressed in percentage of their total consumption, were as follows: 60.4% N (54.4 g DM), 12.4% L (12.1 g DM) and 27.2% D (26.6 g DM) in cats, and 46.2% N (11.6 g DM), 29.9% L (7.5 g DM) and 23.9% D (6.0 g DM) in ferrets. This indicates that cats and ferrets have a clear preference for diets of higher fat content. In all three diets, the digestibility of CP was significantly (p < 0.05) lower (70.1 ± 5.4 vs. 75.9 ± 5.8) while that of EE was significantly (p < 0.05) higher (95.6 ± 1.5 vs. 89.4 ± 5.3) in ferrets than in cats. The average digestible/metabolizable energy (DE/ME) ratio of feeds turned to be 95.6% for cats and 90.6% for the ferrets. From the data one can conclude that the ferret cannot be used as a model animal for cats either for preference or digestibility studies. [source] Study of the conformational profile of the norbornane analogues of phenylalanineJOURNAL OF PEPTIDE SCIENCE, Issue 6 2002Arnau Cordomí Abstract The conformational profile of the eight stereoisomeric 2-amino-3-phenylnorbornane-2-carboxylic acids (2-amino-3-phenylbicyclo[2.2.1]heptane-2-carboxylic acids) has been assessed by computational methods. These molecules constitute a series of four enantiomeric pairs that can be considered as rigid analogues of either L - or D -phenylalanine. The conformational space of their N -acetyl methylamide derivatives has been explored within the molecular mechanics framework, using the parm94 set of parameters of the AMBER force field. Local minimum energy conformations have been further investigated at the ab initio level by means of the Hartree-Fock and second order Moller-Plesset perturbation energy calculations using a 6,31G(d) basis set. The results of the present work suggest that the bulky norbornane structure induces two kinds of conformational constraints on the residues. On one hand, those of a steric nature directly imposed by the bicycle on the peptide backbone and, on the other hand, those that limit the orientations attainable by the phenyl ring which, in turn, reduces further the flexibility of the peptide backbone. A comparative analysis of the conformational profile of the phenylnorbornane amino acids with that of the norbornane amino acids devoid of the ,-phenyl substituent suggests that the norbornane system hampers the residue to adopt extended conformations in favour of C7-like structures. However, the bicycle itself does not impart a clear preference for any of the two possible C7 minima. It is the aromatic side chain, which is forced to adopt an almost eclipsed orientation, that breaks this symmetry introducing a marked preference for a single region of the (,, ,) conformational space in each of the phenylalanine norbornane analogues investigated. Copyright © 2002 European Peptide Society and John Wiley & Sons, Ltd. [source] Survival of juvenile European eels (Anguilla anguilla), transferred among salinities, and developmental shifts in their salinity preferenceJOURNAL OF ZOOLOGY, Issue 1 2005S. R. Crean Abstract After their oceanic migration, juvenile European eels Anguilla anguilla enter estuaries as glass eels, develop into pigmented elvers and migrate into fresh water. Fisheries often transfer such eels abruptly between salinities, principally glass eels and elvers from estuarine to fresh water. It is usually assumed that survival rates are high, but this required systematic investigation. Survival was found to be 100% over 21 days of glass eels and semi-pigmented elvers transferred abruptly from estuary conditions into fresh water, 50% sea water and full sea water. Fully pigmented elvers, however, showed significantly reduced survival when transferred into sea water. Salinity preference experiments with juvenile eels have historically been inconclusive. Here, in a choice chamber design, a clear developmental shift in salinity preference was found, with glass eels preferring 100% sea water, semi-pigmented elvers showing no clear preference and fully pigmented elvers preferring fresh water. We conclude that eel fisheries enhancement by abrupt transfer of juveniles among salinities is largely vindicated. In addition, developmental shifts in salinity preference have been clarified and this aids in the interpretation of eel migration patterns. [source] Repair Sequences in Spanish L2 Dyadic Discourse: A Descriptive StudyMODERN LANGUAGE JOURNAL, Issue 3 2001Peggy Buckwalter This article reports on a qualitative study of dyadic discourse between university students of Spanish as a foreign language (FL). In light of the common acceptance of pair work as an effective pedagogical practice in the FL classroom, the study was designed to explore the social and cognitive behavior of learners as they participated in second language speaking activities. The construct of repair as it is formulated in the ethnomethodological approach to conversation analysis provided the lens through which data were examined. Trouble sources were identified and repair sequences were classified in terms of which learner brought attention to the trouble source and which learner resolved it. A clear preference for self-repair and for self-initiated repair was found. Collaborative repair, as well as unsolicited other-repair, operated almost exclusively on the lexicon, whereas self-initiated self-repair included morphosyntax. The study supports the Vygotskian notion that talk is used for cognitive as well as for social purposes. [source] Custom-devised and generic digital enhancement of images for people with maculopathyOPHTHALMIC AND PHYSIOLOGICAL OPTICS, Issue 4 2009Susan J. Leat Abstract Aim:, The purpose of this study was to compare the effectivity, in terms of the potential usefulness, of digital filters based on either contrast sensitivity (CS) or supra-threshold contrast matching (CM) in enhancing pictures images for people with maculopathy and to investigate whether generic filters (not based on an individual's vision loss) are equally as effective. Effectivity is measured by changes in perceived visibility. Methods:, Thirty-five subjects with maculopathy, aged 20,92 years, took part [13 atrophic age-related macular degeneration (ARMD), 14 exudative ARMD, and 8 juvenile macular dystrophy (JMD)]. CS and supra-threshold CM were measured. A range of CS filters (1 or 2-octave wide band-pass filter using a Gabor or polynomial envelope) with different strengths were developed based on the ratio of the individual's contrast threshold and that of a normal age-related group. Similarly filters were developed based on CM at 3.6% and 27.9% contrast. The following generic filters were also applied with different ,strengths': edge enhancement; sharpening; contrast enhancement; Peli's adaptive enhancement; difference of Gaussian; and an equi-emphasis band-pass filter. The filters were applied to images of faces and general scenes. Subjects were asked to rank the perceived visibility of images (to obtain the best version of each filter) and then to rate the perceived visibility of each image filtered with a particular filter. Results:, In general, subjects with atrophic ARMD and JMD preferred the weaker versions of most of the filters, while those with exudative ARMD did not show such a clear preference. Generally, images of faces were preferred with less enhancement than scenes. The filters based on CM were rated as giving significant improvement, while those based on CS and peak emphasis were not preferred. Of the generic filters, the Peli adaptive enhancement filter was most frequently rated as giving a significant improvement (p < 0.05) followed by the contrast enhancement filter. They gave the same perceived enhancement as the custom-devised filters. Conclusions:, Generic filters, which are easier to apply than the custom-devised filters, are appropriate for rehabilitation purposes. [source] Guanosine-Induced Synaptogenesis in the Adult Brain In VivoTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 12 2009Inmaculada Gerrikagoitia Abstract Astrocytes release factors like cholesterol, apoE, and pleiotropic molecules that influence synaptogenesis in the central nervous system. In vitro studies have shown that guanosine elicits the production and further release of these synaptogenic factors. To demonstrate that such astrocytic factors are synaptogenic in vivo, osmotic pumps were implanted in primary visual cortex (VC) of Sprague-Dawley rats to deliver guanosine. Simultaneous injection of dextran amine as an anterograde tracer at the same site where the osmotic pumps were implanted enabled the morphology of the fibers emerging from the VC to be visualized as well. The guanosine-treated efferent connections from these animals showed a significant increase in the number and size of synaptic boutons along the efferent fibers when compared with controls. A similar increase in the number and size of synaptic boutons was also detected when the cortico,cortical connection to the lateral secondary visual area was studied in more detail. The ensuing morphological changes to the synapses did not show a clear preference for any particular type or site of the axonal branches that integrates this cortical connection. Moreover, the distribution of boutons along the fibers was clearly stochastic according to their size. Thus, guanosine administration appears to open up the possibility of manipulating connections to compensate for total or partial denervation. Anat Rec, 292:1968,1975, 2009. © 2009 Wiley-Liss, Inc. [source] Ascertaining women's choice of title during pregnancy and childbirthAUSTRALIAN AND NEW ZEALAND JOURNAL OF OBSTETRICS AND GYNAECOLOGY, Issue 2 2002Angela S Denning ABSTRACT Methods A questionnaire was administered to 958 women attending the antenatal clinic at Mercy Hospital for Women, Melbourne, to ascertain their choice of title during pregnancy. Midwifery, nursing and medical staff (376 in total) were also invited to respond to a similar questionnaire. Results The response rate was 73.6% from the survey of all women who were overwhelmingly in favour of being called ,patient' as their first choice (34%), followed by ,other' (20%) and then ,mother' (19%). Virtually all women requesting ,other' wished to be called by their name. Women wishing to be called ,patient' for first choice did not significantly differ from the remainder of the study group in age, gestation, number of previous pregnancies, or number of children. When women from the Family Birth Centre (FBC) were analysed as a separate group, they had a clear preference to be called ,other' (unanimously, by their name) than the general antenatal population (odds ratio (OR) 5.1; 95% confidence interval (CI) 3.1, 8.3; p < 0.0001). The staff survey, with a response rate of 84%, also demonstrated that ,patient' was the most popular first choice for patient title. Medical staff were significantly more likely to choose ,patient' (OR 4.2, 95% CI 2.3, 7.7; p < 0.0001), though the term ,patient' was the preferred choice of all staff. [source] Lysosomal cysteine proteases (cathepsins): promising drug targetsACTA CRYSTALLOGRAPHICA SECTION D, Issue 2 2003an Turk Papain-like lysosomal cysteine proteases are processive and digestive enzymes expressed in organisms from bacteria to humans. Their ubiquity alone makes them potential drug targets, with the assumption that appropriate specificities may be achieved. These enzymes have rather short active-site clefts, comprising three well defined substrate-binding subsites (S2, S1 and S1,) and additionally have comparatively broad binding areas (S4, S3, S2,, S3,). This geometry distinguishes them from other protease classes, such as serine and aspartic proteases, with six and eight substrate-binding sites, respectively. Exopeptidases (cathepsins B, C, H and X), in contrast to endopeptidases (such as cathepsins L, S, V and F), possess structural features that facilitate binding of N- and C-terminal groups of substrates in the active-site cleft. Other than a clear preference for free chain termini in the case of exopeptidases, the substrate-binding sites exhibit no strict specificities. Instead, their subsite preferences arise more from specific exclusions of substrate type. This presents a challenge for the design of inhibitors to target a specific cathepsin: only the cumulative effect of an assembly of inhibitor fragments can produce the desired result. The small number of papain-like lysosomal cysteine proteases (11 human enzymes are known) and the small number of substrate-binding sites calls for a innovative and empirical approach. [source] Women's knowledge of and attitudes to first and second trimester screening for Down's syndromeBJOG : AN INTERNATIONAL JOURNAL OF OBSTETRICS & GYNAECOLOGY, Issue 10 2000S. Mulvey Research Fellow (Maternal Fetal Medicine) One hundred women were interviewed at their first hospital antenatal visit to assess their knowledge of, and attitudes to, first versus second trimester screening for Down's syndrome. Overall, the women had limited knowledge of Down's syndrome, and the prenatal screening and diagnostic tests that are available. However, when informed, the majority of women expressed a clear preference for first trimester screening tests for Down's syndrome, regardless of the rate of miscarriage of Down's syndrome pregnancies between 10 and 15 weeks of gestation. These findings have implications for the planning of prenatal Down's syndrome screening programmes. [source] Copper(II)-Mediated Aromatic ortho -Hydroxylation: A Hybrid DFT and Ab Initio ExplorationCHEMISTRY - A EUROPEAN JOURNAL, Issue 1 2008Peter Comba Prof. Dr. Abstract Mechanistic pathways for the aromatic hydroxylation by [CuII(L1)(TMAO)(O)], (L1=hippuric acid, TMAO=trimethylamine N -oxide), derived from the ON bond homolysis of its [CuII(L1)(TMAO)2] precursor, were explored by using hybrid density functional theory (B3LYP) and highly correlated ab initio methods (QCISD and CCSD). Published experimental studies suggest that the catalytic reaction is triggered by a terminal copper,oxo species, and a detailed study of electronic structures, bonding, and energetics of the corresponding electromers is presented. Two pathways, a stepwise and a concerted reaction, were considered for the hydroxylation process. The results reveal a clear preference for the concerted pathway, in which the terminal oxygen atom directly attacks the carbon atom of the benzene ring, leading to the ortho -selectively hydroxylated product. Solvent effects were probed by using the PCM and CPCM solvation models, and the PCM model was found to perform better in the present case. Excellent agreement between the experimental and computational results was found, in particular also for changes in reactivity with derivatives of L1. [source] An experimental test of the symbiosis specificity between the ciliate Paramecium bursaria and strains of the unicellular green alga ChlorellaENVIRONMENTAL MICROBIOLOGY, Issue 8 2007Monika Summerer Summary The ciliate Paramecium bursaria living in mutualistic relationship with the unicellular green alga Chlorella is known to be easily infected by various potential symbionts/parasites such as bacteria, yeasts and other algae. Permanent symbiosis, however, seems to be restricted to Chlorella taxa. To test the specificity of this association, we designed infection experiments with two aposymbiotic P. bursaria strains and Chlorella symbionts isolated from four Paramecium strains, seven other ciliate hosts and two Hydra strains, as well as three free-living Chlorella species. Paramecium bursaria established stable symbioses with all tested Chlorella symbionts of ciliates, but never with symbiotic Chlorella of Hydra viridissima or with free-living Chlorella. Furthermore, we tested the infection specificity of P. bursaria with a 1:1:1 mixture of three compatible Chlorella strains, including the native symbiont, and then identified the strain of the newly established symbiosis by sequencing the internal transcribed spacer region 1 of the 18S rRNA gene. The results indicated that P. bursaria established symbiosis with its native symbiont. We conclude that despite clear preferences for their native Chlorella, the host,symbiont relationship in P. bursaria is flexible. [source] The perceived importance of veal meat attributes in consumer choice decisionsAGRIBUSINESS : AN INTERNATIONAL JOURNAL, Issue 3 2001Gale E. West Animal scientists have recently found a way to produce extremely pale grain-fed veal, thus achieving high quality grade, while averting concerns over unethical treatment and medication residues in milk-fed veal production. Consumers, however, may reject pale cuts of veal labeled as "grain-fed." This article uses questionnaire data from six groceries in the province of Quebec, Canada, to investigate frequency of veal purchases and perceived importance of price, color, and production type as determinants of veal purchases. Consumers do not appear to have clear preferences for milk-fed veal characteristics. Frequency of consumption and importance of veal meat attributes were influenced more by variables of habit formation than by price, income, or education. The veal industry might be advised to encourage consumption of veal as a means to diversify consumers' meat menu. [Econ-Lit citations: D120, Q130] © 2001 John Wiley & Sons, Inc. [source] Feeding on roots in the humus layer by adult pine weevil, Hylobius abietisAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 4 2006Kristina Wallertz Abstract 1,The consumption by adult pine weevil, Hylobius abietis, of the bark of roots present in the humus layer was assessed in a field study conducted in southern Sweden during two years (1998 and 2002). The study sites were divided into two areas: (i) a shelterwood where 80,100 mature Scots pine trees per hectare remained after cutting and (ii) a clearcut where no trees were left. 2,On average, 3741 m2 per hectare of root bark was present in the humus layer, of which 135 m2 was not coniferous but comprised species such as bilberry and broadleaved trees. 3,The mean area debarked by pine weevils was 2.9 m2 per hectare; 2.6 m2 of conifer roots and 0.3 m2 of bilberry roots. Roots of broadleaved trees were almost never consumed. No clear preferences for roots of a specific level of vitality were observed. 4,No consistent difference between the shelterwood and clearcut was found, either in the amount of root bark area available or in the extent of root feeding by pine weevil. 5,A weak negative correlation between debarked areas on roots and seedlings was found, indicating that root feeding may have reduced damage to seedlings. 6,It is concluded that conifer roots in the humus layer constitute a major food source for the pine weevil and can be utilized for a considerable period in both clearcuts and shelterwoods. [source] CONSUMER PERCEPTION OF WHEY AND SOY PROTEIN IN MEAL REPLACEMENT PRODUCTSJOURNAL OF SENSORY STUDIES, Issue 3 2008JESSICA L. CHILDS ABSTRACT Meal replacement products including protein bars, shakes and powdered drinks have increased in demand and sales. The objective of this study was to assess the consumer perception of protein content and type and product claims for meal replacement beverages and bars. The impact of exercise frequency on product perception was also investigated. Focus groups were conducted with exercisers and nonexercisers. An adaptive conjoint analysis survey was subsequently developed and conducted (n = 138 consumers, ages 18,35 years). Relative importance of product attributes was determined through a realistic trade-off scenario. Utility scores were extracted and rescaled by the zero-centered differences method, and two-way analysis of variance was conducted to identify the differences between exercise frequency and product attributes. Both groups preferred bars to beverages, and no clear preferences were observed for protein type, which was consistent with focus group results of low knowledge/understanding of specific proteins. All respondents valued the products with low-fat/fat-free, calcium, all-natural, protein, vitamin/mineral, heart health and muscle-building claims. Exercisers viewed muscle-building claims as more important than nonexercisers. Nonexercisers viewed heart health, calcium and vitamin/mineral claims as more important than exercisers. Three distinct consumer clusters were identified, and both exercise groups were found in all three clusters, although exercise frequency influenced membership in two of the three clusters (P < 0.05). These findings can be used to develop and market meal replacement products to specific consumer groups while leveraging their specific and unique needs. PRACTICAL APPLICATIONS Conjoint analysis provides a useful model of how consumers think during the purchase process and an understanding of the motivation for purchase through the testing of possible claims or product attributes. By applying this method to the purchase process of meal replacement bars and beverages, those in the field of development of these products can benefit from this information by being able to understand the motivation for purchase by the targeted consumer. [source] | ||||||||||||||||