6,518 research outputs found
Influences on the fraction of hydrophobic and hydrophilic black carbon in the atmosphere
Black carbon (BC) is a short term climate forcer that directly warms the atmosphere, slows convection, and hinders quantification of the effect of greenhouse gases on climate change. The atmospheric lifetime of BC particles with respect to nucleation scavenging in clouds is controlled by their ability to serve as cloud condensation nuclei (CCN). To serve as CCN under typical conditions, hydrophobic BC particles must acquire hygroscopic coatings. However, the quantitative relationship between coatings and hygroscopic properties for ambient BC particles is not known nor is the time scale for hydrophobic-to-hydrophilic conversion. Here we introduce a method for measuring the hygroscopicity of externally and internally mixed BC particles by coupling a single particle soot photometer with a humidified tandem differential mobility analyzer. We test this technique using uncoated and coated laboratory generated model BC compounds and apply it to characterize the hygroscopicity distribution of ambient BC particles. From these data we derive that the observed number fraction of BC that is CCN active at 0.2% supersaturation is generally low in an urban area near sources and that it varies with the trajectory of the airmass. We anticipate that our method can be combined with measures of air parcel physical and photochemical age to provide the first quantitative estimates for characterizing hydrophobic-to-hydrophilic conversion rates in the atmosphere.Peer reviewe
Experimental observation of a moving mirror
In this manuscript, we examine the radiative beta decay of free neutrons
measured by the RDK II collaboration. The infrared portion of the emitted
photon spectrum is shown to corroborate a thermal distribution consistent with
the dynamical Casimir effect (DCE). We find the system is thermalized at the
local Fulling-Davies-Unruh temperature predicted by the DCE. Substantiated by
an excellent chi-squared statistic, we present the evidence for the observation
of thermal radiation emitted during the beta decay process in accordance with
an accelerated moving mirror.Comment: 5 pages, 1 figur
THE MARKETING STYLE OF ADVISORY SERVICES FOR CORN AND SOYBEANS IN 1995
The 1995 marketing styles for the 25 market advisory service programs included in the AgMAS Project were developed in two steps. The first step was the construction of a detailed "menu" of the tools and strategies used by each of the advisory programs in marketing corn and soybeans. The menu describes the type of pricing tool, frequency of transactions, and magnitude of transactions. The second step was the development of a daily index of the net amount sold by each market advisory program. To construct such an index, the various futures, options, and cash positions recommended for a program on a given day were weighted by the respective position "delta." When the daily values of the index were plotted for the entire marketing period, the marketing "profile" for a program was generated. The results show that advisory programs made a relatively small number of recommendations that primarily involved cash marketing strategies, not futures and options, non-cash marketing recommendations were typically held open for a short period of time, and the re-harvest amount sold averaged 35 percent for corn and 30 percent for soybeans.advisory services, pricing tools, pricing strategies, assessment of recommendations, D4, C8, D8, M3, Q0, Marketing,
Two Qubits in the Dirac Representation
A general two qubit system expressed in terms of the complete set of unit and
fifteen traceless, Hermitian Dirac matrices, is shown to exhibit novel features
of this system. The well-known physical interpretations associated with the
relativistic Dirac equation involving the symmetry operations of time-reversal
T, charge conjugation C, parity P, and their products are reinterpreted here by
examining their action on the basic Bell states. The transformation properties
of the Bell basis states under these symmetry operations also reveal that C is
the only operator that does not mix the Bell states whereas all others do. In a
similar fashion, expressing the various logic gates introduced in the subject
of quantum computers in terms of the Dirac matrices shows for example, that the
NOT gate is related to the product of time-reversal and parity operators.Comment: 11 page
Mermithid Nematodes: SEM Observations Comparing Hexamethyldisilazane and Critical Point Drying Methods
Morphological features of mermithid nematodes (Mermithidae) were studied with scanning electron microscopy, using hexamethyldisilazane-air drying in comparison with critical point drying via liquid carbon dioxide. Although general morphologic preservation of both HMDS-dried and CP-dried specimens was similar, structural features of the complex cuticle and internal organization were more easily resolved at higher magnifications in the HMDS-dried nematodes. These features include the superficial cuticular annulations, the fibrillar inner cuticle and peg-like microtrabeculae. The previously undescribed microtrabeculae are of special interest since they may facilitate an interaction of the mermithid (and perhaps nameatodes in general) musculature with its body wall that, at least in part, may account for the unique thrashing locomotion so characteristic of these organisms
Rare and Endangered Vetebrates of Ohio
Author Institution: U.S. Soil Conservation Service; Introductory Biology Program, The Ohio State University; School of Natural Resources, The Ohio State University; and Division of Wildlife, Ohio Department of Natural ResourcesThis paper, an annotated list of Ohio's rare and endangered vertebrate species, was compiled to supplement a similar national list and includes 10 mammals, 62 birds, 10 reptiles, 4 amphibians, and 33 fishes. Where possible, suggestions are made both as to causes of the rare or endangered status of these species and as to means of halting the trend. Ratings of endangered, rare, peripheral, or undetermined, as defined for the national classification, are given for each species
Siting prisons, sighting communities: geographies of objection in a planning process
This paper reviews the planning process for a Scottish prison located near a former mining village. Analysing the letters of objection submitted by residents offers an opportunity to explore local views about prison and community and to relate these to the unique social and spatial history of the area. The planning process itself structured how residents were able to express themselves and defined what counted as a relevant objection. After deconstructing this process, the paper then restores and uses as a framework for analysis three geographies of objection stripped from local responses to the development proposal: the emotional, temporal, and spatial. Emotional expressions of objection added intensity and gave meaning to claims about the historical decline of the region and also conveyed a deep sense of the proposed building site as a lived space. Particular grounds of oppositionāover fear of strangers, the fragility of a local orchid, and the pollution from miningāprovide an opportunity to explore the complex nature of place meaning and community identity, ultimately leading to a conclusion that the meaning of place is always in flux. The paper argues that Simmelās classic concept of the stranger, as the outsider who comes to stay, offers a useful analytic in understanding how the quality of proximal remoteness that prisons and other unwanted developments constitute participates in a constantly evolving sense of the local
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