The nature of DNA synthesis by isolated nuclei from cells of a rat tumour

Summary The DNA synthetic activity of nuclei isolated from a solid rat tumour was determined. The nuclei had DNA synthetic properties similar to nuclei from other sources but the time course of the reactions was different.     

On “the application of science to science itself:” chemistry,instruments, and the scientific labor process

The “Instrumental Revolution” in chemistry refers to a transitional period in the mid-20th century during which sophisticated instrumentation based on physical principles was introduced to solve chemical problems. Historical and philosophical reflection on whether the revolution was a scientific one has been dominated by general models of scientific revolution, in particular, those proposed by Thomas Kuhn, I. B. Cohen and Ian Hacking. In this article I propose that the Industrial Revolution is a useful model for understanding the transformation wrought by the increasingly important role of machines in chemical research. Drawing on Marx's analysis of that event, I argue that that the Instrumental Revolution bears a striking resemblance to the industrial one. I offer grounds for thinking that the resemblance is not fortuitous, but rather reflects a general pattern of development involving the mechanization of the labor process. It is suggested that the cognitive consequences of radical changes in the means of production, as exemplified in the Instrumental Revolution, warrant the consideration of whether the latter is an instance of a kind of revolution in science rather than a singular episode.     

The banner-tailed kangaroo rat, Dipodomys spectabilis (Rodentia: Heteromyidae), in Utah

We report the discovery in Utah of Dipodomys spectabilis, a species previously unknown to occur in the state. We searched for D. spectabilis in extreme southeastern Utah, south of the San Juan River, and were successful in finding mounds and burrows characteristic of the species and in capturing one individual. This is the northernmost record for D. spectabilis and extends its known range ~84 km northwest of the nearest previously reported locality (Fruitland, San Juan County, New Mexico). A flea, Meringis rectus, collected from D. spectabilis, is also the first record of its species in Utah. Reportamos el descubrimiento en Utah de Dipodomys spectabilis, una especie cuya presencia en el estado no había sido observada previamente. Buscamos D. spectabilis en el extremo sureste de Utah, al sur del Río San Juan, y logramos encontrar montículos y túneles típicos de esta especie y capturar un espécimen. Este es el registro más al norte para D. spectabilis y se extiende su rango de distribución conocida a ~84 km al noroeste de la localidad más cercana previamente reportada (Fruitland, condado de San Juan, Nuevo Mexico). Es también el primer registro en Utah para Meringis rectus, una pulga recolectada en D. spectabilis.     

Microtopography of microbiotic crusts on the Colorado Plateau, and distribution of component organisms

We analyzed the microtopography of microbiotic soil crusts at 3 sites on the Colorado Plateau of southern Utah and investigated distributions of cyanobacteria and several lichens in distinctive microhabitats created by this topography. At all 3 sites the long axes of linear soil mounds were oriented nonrandomly in a NNW—SSE direction. The conspicuous and consistent orientation of soil mounds may result from a combination of physical and biotic processes. Subtle differences across sites in mound orientation and organismal distribution suggest that these variables may be useful in comparing disturbance histories of crusts retrospectively. Differences in colonization frequencies, abundances, and distributions of microorganisms comprising the crusts, as a function of mound aspect or exposure, suggest that these organisms are associated with particular aspects due to distinctive and favorable microhabitats on these exposures. Polysaccharide sheath material, deposited by cyanobacteria, and associated filaments occurred in greater quantities on ENE than WSW mound exposures, and cover by Collema spp. lichens exhibited the same pattern. Colonization of mounds by common lichen species occurred significantly more frequently on ENE than WSW mound aspects at 2 of 3 sites. In contrast, the 3 most common lichen species, aside from Collema spp., did not exhibit a tendency for greater cover on ENE than WSW mound aspects. Physiological differences between gelatinous cyanolichens and green-algal lichens may explain the different distributional patterns of Collema spp. and the 3 other lichens.     

Avian use of harvested crop fields in North Dakota during spring migration

Broad-spectrum herbicide applications and improved harvesting efficiency of crops have reduced the availability of weed seeds and waste grains for game and nongame wildlife. Over the last decade, corn and soybean plantings have steadily increased in the Prairie Pothole Region (PPR) of North Dakota, while sunflower plantings have declined. The PPR is an important corridor for migratory birds, and changes in food availabilities at stopover habitats may affect how food resources are used. In early spring 2003 and 2004, we compared bird use of harvested fields of sunflower, soybeans, small grains, and corn in the PPR of North Dakota. Across both years and all crop types, we observed 20,400 birds comprising 29 species. Flocks of Lapland Longspurs ( Calcarius lapponicus ) and Horned Larks ( Eremophila alpestris ) and flocks of Red-winged Blackbirds ( Agelaius phoeniceus ) made up 60% and 15%, respectively, of the bird counts. We found that species richness and bird densities were higher in harvested sunflower fields and cornfields than in harvested small-grain and soybean fields, with soybean fields harboring the fewest species and lowest bird density. Blackbird densities tended to be lower in fields tilled after fall harvest than in fields not tilled. These results suggest that some granivorous bird populations in the Northern Great Plains could be positively affected by planting of row crops with postharvest vertical structure (e.g., sunflower, corn) and use of no-till land management practices.     

Oreohelices of Utah, II. Extant status of the Brian Head mountainsnail, Oreohelix parawanensis Gregg, 1941 (Stylommatophora: Oreohelicidae)

The Brian Head mountainsnail, Oreohelix parawanensis , is reported for the 1st time as a living species, and for the 1st time its habitat is described. Preliminary determination of the very limited distribution of this species (≤ 2.3 ha inhabited in ～ 11 ha overall area) is presented. Morphometric data previously had been reported only for the holotype and for 1 topotype; measurements from 37 new specimens as well as 20 paratypes are provided here, and these data show that the lost holotype was not typical of the species. Sizes of reproductive snails and of embryos are also reported.     

Morphometric changes in Yellow-headed Blackbirds during summer in Central North Dakota

Temporal stability of morphometric measurements is desirable when using avian morphology as a predictor of geographic origin. Therefore, to assess their temporal stability, we examined changes in morphology of Yellowheaded Blackbirds ( Xanthocephalus xanthocephalus ) from central North Dakota during summer. Measurements differed among age classes and between sexes. As expected, due to growth and maturation, measurements on hatching-year birds increased over summer. Measurements of adult plumage fluctuated with prebasic molt and exhibited age-specific discontinuities. Body mass of adult birds increased over summer, whereas both culmen length and skull length decreased. Only body length and length of internal skeletal elements were temporally stable in adult Yellow-headed Blackbirds.     

Oreohelices of Utah, I. Rediscovery of the Uinta mountainsnail, Oreohelix eurekensis uinta Brooks, 1939 (Stylommatophora: Oreohelicidae)

The Brian Head mountainsnail, Oreohelix parawanensis , is reported for the 1st time as a living species, and for the 1st time its habitat is described. Preliminary determination of the very limited distribution of this species (≤ 2.3 ha inhabited in ～ 11 ha overall area) is presented. Morphometric data previously had been reported only for the holotype and for 1 topotype; measurements from 37 new specimens as well as 20 paratypes are provided here, and these data show that the lost holotype was not typical of the species. Sizes of reproductive snails and of embryos are also reported.     

Status of the northern rock deermouse, Peromyscus nasutus (Rodentia: Cricetidae), in Utah

Peromyscus nasutus has been considered to occur in Utah since it was first reported in the state in 1935. Authors since then have considered the distribution of P. nasutus to include southeastern Utah. However, the original Utah specimen was later reidentified as Peromyscus boylii . A query of museums revealed only 1 other specimen considered to be P. nasutus from Utah. This specimen was examined and found to be P. boylii . Thus, there is no evidence of the occurrence of P. nasutus in Utah, and the northwesternmost accepted records of this species are in the Chuska Mountains of northeastern Arizona.     

Zoogeography of Great Basin butterflies: patterns of distribution and differentiation

The butterflies of the Great Basin exhibit general patterns of distribution and speciation similar to those found for other taxa, particularly birds. Two major centers of infraspecific differentiation and coinciding distribution limits of taxa are identified, each with three subregions. Great Basin butterflies are characterized by pallidity and substantial endemism below the species level.