8,147 research outputs found

    Arthropods Utilizing Sticky Inflorescences of \u3ci\u3eCirsium Discolor\u3c/i\u3e and \u3ci\u3ePenstemon Digitalis\u3c/i\u3e

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    Cirsium discolor (Muhl) Spreng (Asteraceae) and Penstemon digitalis Nutt. (Scrophulariaceae) produce sticky material only in their inflorescences. While there is a wealth of printed information concerning such sticky traps occurring in other parts of plants, there is relatively little about those specifically in inflorescences. In order to determine whether sticky traps in the inflorescences of these two plant species defend against seed predators and other herbivores and predators, it was necessary to discover what arthropods use them. Literature search revealed very little about arthropods associated with C. discolor, and nothing about those associated with P. digitalis. Observations showed that, for both plant species, pollinators do not come in contact with the traps, and each plant has several seed predators able to successfully avoid the traps. Several predatory arthropods occur on C. discolor. Two of them, a minute pirate bug and a small salticid spider, seem to glean from its sticky traps. A theridiid spider occasionally builds its web in P. digitalis inflorescences, but was not seen to glean from sticky traps. An undescribed pteromalid parasitizes one of the seed predators of P. digitalis. Ants and aphids are deterred by the traps

    Sticky Exudates on the Inflorescences of \u3ci\u3eCirsium Discolor\u3c/i\u3e (Asteraceae) and \u3ci\u3ePenstemon Digitalis\u3c/i\u3e (Scrophulariaceae) as Possible Defense Against Seed Predators

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    From 1982 through 1987, I investigated whether sticky exudates released by Cirsium discolor and Penstemon digitalis in their inflorescences provide defense against seed predators. I tested two hypotheses: 1: Exudates directly deter seed predators, and 2: Insects struggling in exudates attract predatory arthropods that remain and defend the inflorescences against seed predators. These hypotheses predict that neutralizing the stickiness will increase seed predation (by allowing access to more seed predators, or by decreasing the number of predatory arthropods attracted), and therefore decrease successful seed production. Results did not support either hypothesis, with no increase in seed predators (nor decrease in predatory arthropods), and no decrease in seed production, when traps were neutralized

    The Burden of Out-of-Pocket Health Spending Among Older Versus Younger Adults: Analysis from the Consumer Expenditure Survey, 1998-2003

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    Analyzes the extent to which health care spending as a share of income has differed among younger adults versus people ages 65 and older, both at a single point in time (2003) and over the six-year period from 1998 to 2003

    Arthropods Utilizing Sticky Inflorescences of \u3ci\u3eCirsium Discolor\u3c/i\u3e and \u3ci\u3ePenstemon Digitalis\u3c/i\u3e

    Get PDF
    Cirsium discolor (Muhl) Spreng (Asteraceae) and Penstemon digitalis Nutt. (Scrophulariaceae) produce sticky material only in their inflorescences. While there is a wealth of printed information concerning such sticky traps occurring in other parts of plants, there is relatively little about those specifically in inflorescences. In order to determine whether sticky traps in the inflorescences of these two plant species defend against seed predators and other herbivores and predators, it was necessary to discover what arthropods use them. Literature search revealed very little about arthropods associated with C. discolor, and nothing about those associated with P. digitalis. Observations showed that, for both plant species, pollinators do not come in contact with the traps, and each plant has several seed predators able to successfully avoid the traps. Several predatory arthropods occur on C. discolor. Two of them, a minute pirate bug and a small salticid spider, seem to glean from its sticky traps. A theridiid spider occasionally builds its web in P. digitalis inflorescences, but was not seen to glean from sticky traps. An undescribed pteromalid parasitizes one of the seed predators of P. digitalis. Ants and aphids are deterred by the traps

    “Bury Your Head Between My Knees and Seek Pardon”: Gender, Sexuality, and National Conflict in John Okada’s No-No Boy

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    In “‘Bury Your Head Between My Knees and Seek Pardon’: Gender, Sexuality, and National Conflict in John Okada’s 1957 novel, No-No Boy,” I analyze the ways in which the complexities of gendered sexuality expressed by protagonist Ichiro Yamada intersect with post-World War II and Internment-era national identifications for American nisei. I demonstrate that this apparent story of one man’s pursuit to resolve his conflict over national identity is, in reality, a tour de force of literary subversion that not only destabilizes the subterfuge that surrounded internment but also—in its deliberate failure to resolve questions of national conflict on the basis of masculine and heterosexual norms—encourages skepticism about the larger structures of order that allowed internment to happen

    Ecology of Juvenile Walleye Pollock, Theragra chalcogramma: Papers from the workshop "The Importance of Prerecruit Walleye Pollock to the Bering Sea and North Pacific Ecosystems" Seattle, Washington, 28-30 October 1993

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    The Alaska Fisheries Science Center (AFSC), National Marine Fisheries Service (NMFS), hosted an international workshop, 'The Importance of Prerecruit Walleye Pollock to the Bering Sea and North Pacific Ecosystems," from 28 to 30 October 1993. This workshop was held in conjunction with the annual International North Pacific Marine Science Organization (PICES) meeting held in Seattle. Nearly 100 representatives from government agencies, universities, and the fishing industry in Canada, Japan, the People's Republic of China, Russia, and the United States took part in the workshop to review and discuss current knowledge on juvenile pollock from the postlarval period to the time they recruit to the fisheries. In addition to its importance to humans as a major commercial species, pollock also serves as a major forage species for many marine fishes, birds, and mammals in the North Pacific region. (PDF file contains 236 pages.

    The Sensitivity of Family Income to Changes in Family Structures and Job Change in the United States and Germany

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    Income Components and the Stability of Family Income in Western Germany and the United States

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    Orientation relationship between metallic thin films and quasicrystalline substrates.

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    We present experimental results on the structure of Ag thin films grown on high-symmetry surfaces of both quasicrystals and approximants. For coverages above ten monolayers, Ag form fcc nanocrystals with (111) plane parallel to the surface plane. Depending on the substrate surface symmetry, the Ag nanocrystals exist in one, two or five different orientations, rotated by a multiple of 2π/30. The orientation relationship between crystalline films and substrates appears to be determined by the following principles: high atomic density rows of the adsorbate are aligned along high atomic density rows of the substrate

    STM study of the atomic structure of the icosahedral Al-Cu-Fe fivefold surface

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    We use scanning tunneling microscopy (STM) to investigate the atomic structure of the icosahedral (i-) Al-Cu-Fe fivefold surface in ultra high vacuum (UHV). Studies show that large, atomically flat terraces feature many ten-petal “flowers” with internal structure. The observed flower patterns can be associated with features on Al rich dense atomic planes generated from two-dimensional cuts of bulk models based on x-ray and neutron diffraction experiments. The results confirm that the fivefold surface of i-Al-Cu-Fe corresponds to a bulk-terminated plane
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