151 research outputs found

    The deglacial history of surface and intermediate water of the Bering Sea

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    Author Posting. © The Authors, 2005. This is the author's version of the work. It is posted here by permission of Elsevier B. V. for personal use, not for redistribution. The definitive version was published in Deep Sea Research Part II: Topical Studies in Oceanography 52 (2005): 2163-2173, doi:10.1016/j.dsr2.2005.07.004.The lithology of deglacial sediments from the Bering Sea includes intervals of laminated or dysaerobic sediments. These intervals are contemporaneous with the occurrence of laminated sediments from the California margin and Gulf of California, which suggests widespread low-oxygen conditions at intermediate depths in the North Pacific Ocean. The cause could be reduced intermediate water ventilation, increased organic carbon flux, or a combination of the two. We infer abrupt decreases of planktonic foraminifer δ18O at 14,400 y BP and 11,650 y BP, which may be a combination of both freshening and warming. On the Shirshov Ridge, the abundance of sea-ice diatoms of the genus Nitzschia reach local maxima twice during the deglaciation, the latter of which may be an expression of the Younger Dryas. These findings expand the extent of the expression of deglacial millennial-scale climate events to include the northernmost Pacific.The Oak Foundation of Boston, Massachusetts, and the WHOI Academic Programs Office provided support for Mea Cook. This project was funded by NSF grant OPP-9912122

    Spiking Patterns and Their Functional Implications in the Antennal Lobe of the Tobacco Hornworm Manduca sexta

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    Bursting as well as tonic firing patterns have been described in various sensory systems. In the olfactory system, spontaneous bursts have been observed in neurons distributed across several synaptic levels, from the periphery, to the olfactory bulb (OB) and to the olfactory cortex. Several in vitro studies indicate that spontaneous firing patterns may be viewed as “fingerprints” of different types of neurons that exhibit distinct functions in the OB. It is still not known, however, if and how neuronal burstiness is correlated with the coding of natural olfactory stimuli. We thus conducted an in vivo study to probe this question in the OB equivalent structure of insects, the antennal lobe (AL) of the tobacco hornworm Manduca sexta. We found that in the moth's AL, both projection (output) neurons (PNs) and local interneurons (LNs) are spontaneously active, but PNs tend to produce spike bursts while LNs fire more regularly. In addition, we found that the burstiness of PNs is correlated with the strength of their responses to odor stimulation – the more bursting the stronger their responses to odors. Moreover, the burstiness of PNs was also positively correlated with the spontaneous firing rate of these neurons, and pharmacological reduction of bursting resulted in a decrease of the neurons' responsiveness. These results suggest that neuronal burstiness reflects a physiological state of these neurons that is directly linked to their response characteristics

    Ss-Sl2, a Novel Cell Wall Protein with PAN Modules, Is Essential for Sclerotial Development and Cellular Integrity of Sclerotinia sclerotiorum

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    The sclerotium is an important dormant body for many plant fungal pathogens. Here, we reported that a protein, named Ss-Sl2, is involved in sclerotial development of Sclerotinia sclerotiorum. Ss-Sl2 does not show significant homology with any protein of known function. Ss-Sl2 contains two putative PAN modules which were found in other proteins with diverse adhesion functions. Ss-Sl2 is a secreted protein, during the initial stage of sclerotial development, copious amounts of Ss-Sl2 are secreted and accumulated on the cell walls. The ability to maintain the cellular integrity of RNAi-mediated Ss-Sl2 silenced strains was reduced, but the hyphal growth and virulence of Ss-Sl2 silenced strains were not significantly different from the wild strain. Ss-Sl2 silenced strains could form interwoven hyphal masses at the initial stage of sclerotial development, but the interwoven hyphae could not consolidate and melanize. Hyphae in these interwoven bodies were thin-walled, and arranged loosely. Co-immunoprecipitation and yeast two-hybrid experiments showed that glyceraldehyde-3-phosphate dehydrogenase (GAPDH), Woronin body major protein (Hex1) and elongation factor 1-alpha interact with Ss-Sl2. GAPDH-knockdown strains showed a similar phenotype in sclerotial development as Ss-Sl2 silenced strains. Hex1-knockdown strains showed similar impairment in maintenance of hyphal integrity as Ss-Sl2 silenced strains. The results suggested that Ss-Sl2 functions in both sclerotial development and cellular integrity of S. sclerotiorum

    Paleontology of leaf beetles

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    `The rate of evolution in any large group is not uniform; there are periods of relatise stability, and periods of comparatively rapid change.' Cockerell and LeVeque, 1931 To Yenli Ych, my beloved wife, a most wonderful person! The fossil record of the Chrysomelidae can be tentatively traced back to the late Paleozoic to early Mesozoic Triassic. Mesozoic records at least 9 subfamilies, 19 genera, and 35 species, are represented by the Sagrinae, the exclusively Mesozoic Proto scelinae, Clytrinae, Cryptocephalinae, Eumolpinae, Chrysomelinae. Galerucinac, Alticinae, and Cassidinae. Cenozoic records at least 12 subfamilies- 63 % of the extant- 12! genera, and 325 species, include the same extant subfamilies as well as the Donaciinae, Zeugophorinae, Criocerinae, and Hispinae and can be frequently identified to genus, especially if preserved in amber. Quaternary records are often identified to extant species. tn total, at least t3! genera about 4 % of total extant, and 357 species < 1 % have been reported. At least, 24 genera <1 % of the extant seem to be extinct. Although reliable biological information associated with the fossil chrysomelids is very scarce, it seems that most of the modern host-plant associations were established, at least, in the late Mesozoic to early Cenozoic. As a whole, stasis seems to be the general rule of the chrysomelid fossil record. Together with other faunal elements, chrysomelids, especially donaciines, have been used as biogeographic and paleoclimatological indicators in the Holocene. I

    Not all men are sexually coercive: A preliminary investigation of the moderating effect of mate desirability on the relationship between female infidelity and male sexual coercion

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    Previous research has demonstrated the utility of men’s perceptions of their partner’s infidelity as a predictor of male sexual coercion in the context of an intimate relationship (Goetz and Shackelford, 2006 and Starratt, in press). Not all men who suspect partner infidelity are sexually coercive, however. Using reports secured from 280 men in a committed, sexual relationship with a woman, the current research provides preliminary evidence of a moderating effect of relative mate desirability in the relationship between perceptions of female infidelity and male sexual coercion. Specifically, men’s perceptions of their partner’s infidelity are positively related to men’s sexual coercion only in those relationships in which the man perceives that he is of equal or greater desirability than his partner. Men’s perceptions of their partner’s infidelity are not related to sexual coercion by men who perceive that they are less desirable than their partners. The discussion addresses interpretations of these findings, limitations of the current study, and directions for future research

    Male mate retention mediates the relationship between female sexual infidelity and female-directed violence

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    Previous research has documented relationships between (1) female sexual infidelity and men’s non-violent mate retention behaviors, and (2) men’s non-violent mate retention behaviors and partner-directed violence. In the two studies, we examined two additional relationships: (1) the relationship between accusations of female sexual infidelity and men’s partner-directed violence and (2) whether men’s direct guarding mate retention behaviors mediates the relationship between accusations of female sexual infidelity and men’s partner-directed violence. The results indicate that (1) accusations of female sexual infidelity predict men’s partner-directed violence, (2) men’s reports of direct guarding mediates the relationship between accusations of partner sexual infidelity and partner-directed violence (Study 1, N = 165) and (3) women’s reports of men’s direct guarding partially mediates the same relationship (Study 2, N = 306). The discussion addresses sex differences identified in the mediation analyses, notes limitations of the research, and highlights directions for future research

    Positive Affective Priming Decreases the Middle Late Positive Potential Response to Negative Images

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    INTRODUCTION: This study aims to expand on previous literature showing that incidental emotion state priming in a specific domain leads to a higher probability that the primed emotion domain will be activated during a subsequent task. METHODS: To that end, we investigated the influence of happy, fearful, and neutral incidental emotion state priming on subsequent responses to emotionally negative and neutral pictures, measured by the event-related potential (ERP) late positive potential (LPP). New to our study, we examined the influence of affective priming on the LPP response (analyzed separately at early and middle latency ranges) to emotional pictures in both the foveal and extrafoveal presentation locations. RESULTS: Following both fearful and neutral incidental state priming, both the early and middle LPP latency ranges overwhelmingly differentiated between negative and neutral pictures. Following happy incidental state priming, however, the LPP response failed to differentiate between negative and neutral pictures by the middle LPP latency range (800-1,000 ms). These results suggest that incidental happy states can have a protective effect when viewing aversive stimuli. Additionally, the LPP showed greater sensitivity to negative stimuli when presented extrafoveally compared to foveally. CONCLUSIONS: Overall, our findings suggest that incidental affective state and stimulus location influence emotional processing differentially for emotionally negative and emotionally neutral stimuli
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