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Features Only (feature + only)
Selected AbstractsEvolution of the nose and nasal skeleton in primatesEVOLUTIONARY ANTHROPOLOGY, Issue 4 2007Timothy D. Smith Abstract One traditional diagnostic feature of the Order Primates is a decreased emphasis on olfaction.1, 2 Some authors attribute this feature only to tarsiers and anthropoids, either through convergence or as a common feature of haplorhines.2,4 Other authors de-emphasize olfaction relative to vision,5,7 which does not necessarily denote olfactory reduction per se. There are lengthy roots to this discussion. The importance of the sense of smell to at least some primates, humans in particular, has long been viewed as secondary to the importance of visual, auditory, and tactile senses. Smell, or olfaction, is viewed as the primitive special sense, the stimuli perceived in an unconscious manner, submerged relative to higher neural functions,1 and a sense that has been increasingly reduced during the course of primate evolution.1,8 Anatomical structures related to olfaction differ profoundly in proportions and complexity between higher taxonomic groups of primates (Haplorhini, Strepsirrhini). These anatomical differences are beyond dispute (Box 1). However, the relationship between the anatomical differences and primate sensory abilities, and hence the validity of using them to group primates into "microsmatic" or "macrosmatic" categories,9, 10 is less clear when we examine the physiological and genetic data on primate olfaction. [source] THE IMPORTANCE OF PREADAPTED GENOMES IN THE ORIGIN OF THE ANIMAL BODYPLANS AND THE CAMBRIAN EXPLOSIONEVOLUTION, Issue 5 2010Charles R. Marshall The genomes of taxa whose stem lineages branched early in metazoan history, and of allied protistan groups, provide a tantalizing outline of the morphological and genomic changes that accompanied the origin and early diversifications of animals. Genome comparisons show that the early clades increasingly contain genes that mediate development of complex features only seen in later metazoan branches. Peak additions of protein-coding regulatory genes occurred deep in the metazoan tree, evidently within stem groups of metazoans and eumetazoans. However, the bodyplans of these early-branching clades are relatively simple. The existence of major elements of the bilaterian developmental toolkit in these simpler organisms implies that these components evolved for functions other than the production of complex morphology, preadapting the genome for the morphological differentiation that occurred higher in metazoan phylogeny. Stem lineages of the bilaterian phyla apparently required few additional genes beyond their diploblastic ancestors. As disparate bodyplans appeared and diversified during the Cambrian explosion, increasing complexity was accommodated largely through changes in cis -regulatory networks, accompanied by some additional gene novelties. Subsequently, protein-coding genic richness appears to have essentially plateaued. Some genomic evidence suggests that similar stages of genomic evolution may have accompanied the rise of land plants. [source] Global summer monsoon rainy seasonsINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 12 2008Suping Zhang Abstract A concise and objective definition of monsoon rainy season characteristics is proposed for worldwide monsoon regions. The result highlights six major summer monsoon rainy season domains and the mean dates of the local onset, peak and withdrawal phases of the summer monsoon rainy season. The onset phases occur progressively later poleward in the continental domains but primarily eastward in the oceanic monsoon regions. The rainy season retreats equatorward over the continental and oceanic monsoon regions. The length of the rainy season decreases poleward and shorter rainy season can also be found over the outskirts of warm water. Some exceptions exist in terms of the characteristics of rainy season, e.g. the westward advance of rainy season over North Africa and an apparently prolonged rainy season in the Korean peninsula. The results here are basically compatible with those obtained in previous studies on regional monsoons. A definition of the seasonal wind overturning is proposed. Combining rainfall and winds, we stratify the global monsoon into strong and weak categories. The strong monsoons are typically in the regions with both concentration of summer rainfall and annual reversal of low-level winds, while the weak monsoon features only a contrasting wet,dry season. Seemingly, some mid-latitude regions with wind reversals are not monsoonal because of the reversals being opposite to the monsoon overturning and the rainfall patterns being more or less Mediterranean. The comparison between the monsoon domains derived from Climate Prediction Center (CPC) Merged Analysis of Precipitation (CMAP) and the 40-year European Centre for Medium-Range Weather Forecasts Re-Analysis (ERA-40), the Japanese 25-year Reanalysis (JRA-25) and National Centers for Environmental Prediction (NCEP) datasets show good capabilities of the reanalyses in demarcation of the major monsoon rainy season domains in the tropics and subtropics. But the reanalyses are less realistic in the mid-latitudes of Eurasia and North America. The result here provides the simple yet objective definitions of monsoon domain, onset, peak and withdrawal which are useful for validation of GCMs. Copyright © 2008 Royal Meteorological Society [source] An Evaluation of the Compensation Required by European Union Cereal Growers to Accept the Removal of Price SupportJOURNAL OF AGRICULTURAL ECONOMICS, Issue 3 2003Rob Fraser Motivated by the policy trend of exposing European Union farmers to more market risk by reducing price support, this paper evaluates the compensation required by EU cereal growers to accept the complete removal of price support. Additional considerations are whether this policy change also includes the removal of set-aside, or features only a partial removal of price support. A model is developed which captures the main on- and off-farm factors influencing grower perceptions of the impact of this policy change. This model is subjected to a numerical analysis which shows that divergent assessments of the expected profitability of releasing to production land previously set-aside mean growers are unlikely to agree whether compensation is even required. It is concluded that the retention of set-aside for environmental purposes is likely to mean growers are more united in their perception of the need for, and amount of, compensation to accept the removal of price support. [source] Functional site profiling and electrostatic analysis of cysteines modifiable to cysteine sulfenic acidPROTEIN SCIENCE, Issue 2 2008Freddie R. Salsbury Jr Abstract Cysteine sulfenic acid (Cys-SOH), a reversible modification, is a catalytic intermediate at enzyme active sites, a sensor for oxidative stress, a regulator of some transcription factors, and a redox-signaling intermediate. This post-translational modification is not random: specific features near the cysteine control its reactivity. To identify features responsible for the propensity of cysteines to be modified to sulfenic acid, a list of 47 proteins (containing 49 known Cys-SOH sites) was compiled. Modifiable cysteines are found in proteins from most structural classes and many functional classes, but have no propensity for any one type of protein secondary structure. To identify features affecting cysteine reactivity, these sites were analyzed using both functional site profiling and electrostatic analysis. Overall, the solvent exposure of modifiable cysteines is not different from the average cysteine. The combined sequence, structure, and electrostatic approaches reveal mechanistic determinants not obvious from overall sequence comparison, including: (1) pKas of some modifiable cysteines are affected by backbone features only; (2) charged residues are underrepresented in the structure near modifiable sites; (3) threonine and other polar residues can exert a large influence on the cysteine pKa; and (4) hydrogen bonding patterns are suggested to be important. This compilation of Cys-SOH modification sites and their features provides a quantitative assessment of previous observations and a basis for further analysis and prediction of these sites. Agreement with known experimental data indicates the utility of this combined approach for identifying mechanistic determinants at protein functional sites. [source] | ||||||||||