A recent test for the existence of suture zones in North America, based on hybrid zones studied since 1970, found support for only two of the 13 suture zones identified by Remington in 1968 (Swenson ...and Howard2004). One limitation of that recent study was the relatively small number of hybrid zones available for mapping. In this study, we search for evidence of clustering of contact zones between closely related taxa using data not only from hybrid zones but from species range maps of trees, birds, and mammals and from the position of phylogeographic breaks within species. Digital geographic range maps and a geographic information system approach allowed for accurate and rapid mapping of distributional data. Areas of contact between closely related species and phylogeographic breaks within species clustered into areas characterized by common physiographic features or predicted by previously hypothesized glacial refugia. The results underscore the general importance of geographic barriers to dispersal (mountain chains) and climate change (periods of cooling alternating with periods of warming, which lead to the contraction and expansion of species ranges) in species evolution.
Two experiments examine the existence of, and explanation for, emotional contagion effects on product attitudes. In the first experiment, emotional contagion occurred among “receivers” who “caught” a ...happy emotion from “senders” whom the receivers liked. The relationship between the emotion experienced by senders and receivers was found to be mediated by receivers mimicking smiling on the part of senders. Exposing receivers to happy senders they liked also resulted in receivers having a positive attitudinal bias toward a product. The happiness experienced by receivers via contagion was found to mediate the effects of sender emotion and receiver liking of the sender on receiver product attitudes. The second experiment replicated the first while demonstrating that observation of the facial expressions of senders by receivers, thus allowing mimicking of smiling, was a necessary condition for emotional contagion to occur. The relevance of emotional contagion for understanding consumer behavior across various substantive domains is discussed.
Two field experiments demonstrate that additive effects of heuristic and systematic processing can explain door-in-the-face technique (DITF) compliance. In Study 1, additive effects of heuristic and ...systematic processing resulted in an increase in charitable donations. Study 2 replicated the additive effects mean differences observed in the first. Attitude toward a charitable issue was also more strongly correlated with donations in a strong arguments than a no arguments DITF condition, compatible with an additive effects explanation. Both studies indicate that rational processing of argument information has a significant and independent effect on donations in addition to traditional heuristic processing typically inferred in explaining DITF compliance.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Two of the most well-supported patterns to have emerged over the past two decades of research in evolutionary biology are the occurrence of divergent natural selection acting on many male and female ...reproductive tract proteins and the importance of postmating, prezygotic phenotypes in reproductively isolating closely related species. Although these patterns appear to be common across a wide variety of taxa, the link between them remains poorly documented. Here, we utilize comparative proteomic techniques to determine whether or not there is evidence for natural selection acting on the ejaculate proteomes of two cricket species (Allonemobius fasciatus and A. socius) which are reproductively isolated primarily by postmating, prezygotic phenotypes. In addressing this question, we compare the degree of within-species polymorphism and between-species divergence between the ejaculate and thorax proteomes of these two species. We found that the ejaculate proteomes are both less polymorphic and more divergent than the thorax proteomes. Additionally, we assessed patterns of nucleotide variation for two species-specific ejaculate proteins and found evidence for both reduced levels of variation within species and positive selection driving divergence between species. In contrast, non-species-specific proteins exhibited higher levels of within-species nucleotide variation and no signatures of positive selection. Nucleotide and putative functional data for the two species-specific proteins, along with data for a third protein (ejaculate serine protease), suggest that all three of these genes are candidate speciation genes in need of further study. Overall, these patterns of proteome and nucleotide divergence provide support for the hypothesis that there is a causative link between selection-driven divergence of male ejaculate proteins and the evolution of postmating, prezygotic barriers to gene flow within Allonemobius.
The opto-fluidic ring resonator (OFRR) is a sensitive label-free optical biosensor that is uniquely well suited for photonic and fluidic integration. For the first time we have explored the utility ...of this novel instrument for the analysis of methylation in oligonucleotides using the MBD-2 (methyl binding) protein as the capture molecule. This application has strong relevance to cancer research and future clinical tools through the study of methylation patterns in important gene promoters. In this work we quantitatively characterized the OFRR's response to artificially methylated ssDNA and dsDNA as a function of the number of methylated cytosines and DNA concentration. The effect of hemi- versus fully methylated oligonucleotides was also investigated. Additionally, anti 5-methylcytidine antibody was also used as the capture molecule and compared with MBD-2. It is found that the antibody has stronger affinity for ssDNA, whereas MBD-2 is much better at binding dsDNA.
The current understanding of reference pricing requires broadening to reflect contemporary advertising practices and shopping behavior. A content analysis of 13,594 newspaper retail advertisements ...reveals that it is uncommon for reference pricing to be used alone in advertisements: 87.2% of the advertisements featuring reference pricing also include limited-time availability (i.e., "Three days only!") or sale announcements in the headline or copy. Using dual-process theories of persuasion as a conceptual framework, the authors conduct three field experiments that compare the conditions under which the use of limited-time availability and sale announcements in advertisements that feature reference prices affects consumer price perceptions and store shopping intentions. The findings yield three insights for reference price advertising. First, reference pricing results in favorable price perceptions and store shopping intentions only when consumers are shopping for a product. Second, when consumers are shopping for a product, reference pricing paired with limited-time availability results in more favorable price perceptions and store shopping intentions than the use of either technique alone. Third, the use of sale announcements and limited-time availability in reference price advertisements has a favorable effect on price perceptions and store shopping intentions when consumers are not shopping for a product.
Optofluidic lasers are of particular interest for lab-on-a-chip-type devices, with broad spectral tunability, convenient microfluidic integration, and a small footprint. Optofluidic ring resonator ...(OFRR) lasers are advantageous in terms of size but typically generate nondirectional emission that is of minimal practical use. We introduce two unique geometries for soft-lithography-based OFRR lasers--side-coupled rings and spiral rings--both of which can be produced in polydimethyl siloxane substrates with contact molding. These rings utilize evanescent and direct butt-coupling, respectively, to effectively couple the OFRR laser emission into microfluidic channels. A laser threshold of a few to tens of microJ/mm(2) is achieved.
Science policy analysts have focused recently on the federal budget sequester and the dramatic effects it could have on funding scientific R&D in US universities, certainly a serious problem. But ...looking only at the sequester misses the larger picture. The sequester simply makes acute a chronic condition that has been getting worse for years. Even if Congress removed the sequester tomorrow and R&D funding returned to pre-sequester levels, university researchers would still face serious and growing problems in funding their research programs, systemic problems that arise from the R&D funding system and incentive structure that the federal government put in place after World War II. This reality dictates that policymakers, research administrators, and the scientific community must adjust to continuing low success rates if scientific research is to continue to flourish on university and college campuses.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
10.
DO SUTURE ZONES EXIST? Swenson, Nathan G; Howard, Daniel J
Evolution,
11/2004, Letnik:
58, Številka:
11
Journal Article
Recenzirano
Remington (1968) argued that 13 suture zones exist in North America. Remington defined a suture zone as, “a band of geographic overlap between major biotic assemblages, including some pairs of ...species or semispecies which hybridize in the zone” (p. 322). Although initially controversial, the idea that suture zones exist has picked up momentum over the past decade, due largely to the phylogeographic work of Hewitt, Avise, and their colleagues. Nevertheless, the reality of suture zones has not yet been subjected to rigorous analysis using statistical and geographic information system (GIS) approaches. To test for the existence of Remington's suture zones, we first identified 117 terrestrial hybrid zones in Canada and the United States through a literature search for the key words “cline,” “contact zone,” “hybrid zone,” and “hybridization” in articles published between 1970 and 2002. The 117 hybrid zones were mapped using a GIS approach and compared with a digitized version of Remington's original suture zone map. Overall, there does appear to be an association between hybrid zones and suture zones, but this association is largely attributable to clustering of hybrid zones in only two of the 13 suture zones recognized by Remington. The results suggest that evolutionary biologists should retain some skepticism toward Remington's suture zones.
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