Theory of one-dimensional double-barrier quantum pump in two-frequency signal regime

A one-dimensional system with two $\delta$-like barriers or wells bi-chromaticaly oscillating at frequencies $\omega$ and $2\omega$ is considered. The alternating signal leads to the direct current across the structure (even in a symmetric system). The properties of this quantum pump are studied in a wide range of the system parameters.Comment: 4 pages, 5 figure

Methylphenidate treatment beyond adolescence maintains increased cocaine self-administration in the spontaneously hypertensive rat model of attention deficit/hyperactivity disorder

Past research with the spontaneously hypertensive rat (SHR) model of attention deficit/hyperactivity disorder showed that adolescent methylphenidate treatment enhanced cocaine abuse risk in SHR during adulthood. The acquisition of cocaine self-administration was faster, and cocaine dose-response functions were shifted upward under fixed-ratio and progressive ratio schedules compared to adult SHR that received adolescent vehicle treatment or to control strains that received adolescent methylphenidate treatment. The current study determined if extending treatment beyond adolescence would ameliorate long-term consequences of adolescent methylphenidate treatment on cocaine abuse risk in adult SHR. Treatments (vehicle or 1.5mg/kg/day oral methylphenidate) began on postnatal day 28. Groups of male SHR were treated with vehicle during adolescence and adulthood, with methylphenidate during adolescence and vehicle during adulthood, or with methylphenidate during adolescence and adulthood. The group receiving adolescent-only methylphenidate was switched to vehicle on P56. Cocaine self-administration began on postnatal day 77, and groups receiving methylphenidate during adolescence and adulthood were treated either 1-h before or 1-h after daily sessions. At baseline under a fixed-ratio 1 schedule, cocaine self-administration (2h sessions; 0.3mg/kg unit dose) did not differ among the four treatment groups. Under a progressive ratio schedule (4.5h maximum session length; 0.01-1.0mg/kg unit doses), breakpoints for self-administered cocaine in SHR receiving the adult methylphenidate treatment 1-h pre-session were not different from the vehicle control group. However, compared to the vehicle control group, breakpoints for self-administered cocaine at the 0.3 and 1.0mg/kg unit doses were greater in adult SHR that received adolescent-only methylphenidate or received methylphenidate that was continued into adulthood and administered 1-h post-session. These findings suggest that extending methylphenidate treatment beyond adolescence does not ameliorate explicitly the long-term consequences of adolescent methylphenidate treatment. Pre-session methylphenidate may mask temporarily the detection of an increase in cocaine self-administration following chronic methylphenidate treatment.R01 DA011716 - NIDA NIH HH

Development tests for the 2.5 megawatt Mod-2 wind turbine generator

The 2.5 megawatt MOD-2 wind turbine generator test program is discussed. The development of the 2.5 megawatt MOD-2 wind turbine generator included an extensive program of testing which encompassed verification of analytical procedures, component development, and integrated system verification. The test program was to assure achievement of the thirty year design operational life of the wind turbine system as well as to minimize costly design modifications which would otherwise have been required during on site system testing. Computer codes were modified, fatigue life of structure and dynamic components were verified, mechanical and electrical component and subsystems were functionally checked and modified where necessary to meet system specifications, and measured dynamic responses of coupled systems confirmed analytical predictions

Multiwavelength Monitoring of the Dwarf Seyfert 1 Galaxy NGC 4395. IV. The Variable UV Absorption Lines

We report the detection of variable UV absorption lines in NGC 4395, based on UV observations with the HST STIS carried out in April and July, 2004, as part of a reverberation-mapping campaign. Low-ionization lines of O I, N I, Si II, C II, and Fe II, are present in the low-state spectra (April 2004) at a velocity v_shift=-250 km/s (system A_l), and additional high-ionization lines of C IV and N V appear in the high-state spectra (July 2004) at v_shift=-250 km/s (system A_h) and at v_shift=-840 km/s (system B). The absence of absorption from the low metastable levels of Si II implies a density <~10^3 cm^(-3) for system A_l, indicating a location outside the narrow line region (NLR). System A_h is peculiar as only N V absorption is clearly detected. A high N V/C IV absorption ratio is expected for a high metallicity absorber, but this is excluded here as the metallicity of the host galaxy and of the nuclear gas is significantly subsolar. A simple acceptable model for systems A_h and B is an absorber located between the broad line region (BLR) and the NLR, which absorbs only the continuum and the BLR. At the low-state the strong narrow emission lines of C IV and N V dominate the spectrum, making the absorption invisible. At the high-state the absorbed continuum and BLR emission dominate the spectrum. Thus, the change in the observed absorption does not reflect a change in the absorber, but rather a change in the continuum and BLR emission from behind the absorber, relative to the emission from the NLR in front of the absorber. Studies of the absorption line variability in highly variable objects can thus break the degeneracy in the absorber distance determination inherent to single epoch studies.Comment: Accepted for publication in The Astrophysical Journa

The Path of Internet Law: An Annotated Guide to Legal Landmarks

The evolution of the Internet has forever changed the legal landscape. The Internet is the world’s largest marketplace, copy machine, and instrumentality for committing crimes, torts, and infringing intellectual property. Justice Holmes’s classic essay on the path of the law drew upon six centuries of case reports and statutes. In less than twenty-five years, Internet law has created new legal dilemmas and challenges in accommodating new information technologies. Part I is a brief timeline of Internet case law and statutory developments for Internet-related intellectual property (IP) law. Part II describes some of the ways in which the Internet is redirecting the path of IP in a globalized information-based economy. Our broader point is that every branch of substantive and procedural law is adapting to the digital world. Part III is the functional equivalent of a GPS for locating the latest U.S. and foreign law resources to help lawyers, policymakers, academics and law students lost in cyberspace

Origins and Relationships of the Mixed Mesophytic Forest of Oregon-Idaho, China, and Kentucky: Review and Synthesis

The Arcto-Tertiary Geoflora concept of Ralph Chaney, that the Mixed Mesophytic Forest of eastern Asia and eastern North America are relicts of a Northern Hemisphere high-latitude circumglobal deciduous forest of the Late Cretaceous–Early Tertiary that migrated south to the temperate zone as an intact unit, was shown by Wolfe and others to be invalid. To explain the origin and development of these disjunct forests, Wolfe and Tiffney developed the boreotropical hypothesis. Accordingly, a paratropical (near-tropical) rainforest flora containing a mixture of tropical, paratropical, and temperate genera developed at several places in the middle latitudes of the Northern Hemisphere in the Eocene and spread around the globe via the Bering and North Atlantic land bridges and shores of the Tethys Seaway. Further, the Mixed Mesophytic Forest of eastern Asia and eastern North America developed independently after disruption of the boreotropical flora by subsequent changes in climate and geography, thus accounting for differences in the flora and physiognomy of the present-day Mixed Mesophytic Forest in the two areas. The fruit and seed flora of the Middle Eocene Clarno Nut Beds of Oregon are representative of the boreotropical forest. In response to climatic cooling during the Eocene–Oligocene transition, this broad-leaved evergreen rainforest was replaced by a temperate broad-leaved deciduous (Mixed Mesophytic) forest, which remained present in the Pacific Northwest through most of the Miocene. The Early Oligocene Bridge Creek flora of Oregon, the Middle Miocene Succor Creek flora of eastern Oregon and adjacent Idaho, and the Middle Miocene Clarkia and Musselshell Creek floras of northern Idaho are good examples of the Mixed Mesophytic Forest. These Oligocene–Miocene fossil floras include important genera in the present-day Mixed Mesophytic Forest of eastern Asia and eastern North America, as well as those that today occur only in eastern Asia or only in eastern North America. Using Graham as the primary source of, and guide to, information on microfossil and megafossil plant paleoassemblages and paleoclimates in eastern North America, we chart the Late Cretaceous–Tertiary sequence of vegetation and climate for Kentucky. Further, we briefly review the palynofloral provinces in which Kentucky was situated during the Middle and Early Cretaceous. In contrast to the Mixed Mesophytic Forest flora (a component of the boreotropical forest) of the Middle Eocene Clarno Nut Beds, the Middle Eocene Claiborne flora of Tennessee and Kentucky represents a semideciduous tropical dry forest dominated by Leguminosae taxa that have strong phylogenetic and biogeographical relationships with the Old World and tropical South America. Apparently, this dry forest developed from a Paleocene–Early Eocene tropical rainforest following a decrease in amount and an increase in seasonality of rainfall. The Mixed Mesophytic Forest developed from this seasonally dry forest following the Eocene as a result of an increase in the amount of rainfall and a decrease in its seasonality. The hypothesis that closely related disjunct taxa between eastern Asia and eastern and western North America represent relicts of a circumglobal Mixed Mesophytic Forest in the Miocene is supported by fossil and molecular phylogenetic data