721 research outputs found

    Luminosities of High-Redshift Objects in an Accelerating Universe

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    The results from the Supernova Cosmology Project indicate a relation between cosmic distance and redshift that corresponds to an accelerating Universe, and, as a consequence, the presence of an energy component with negative pressure. This necessitates a re-evaluation of such astrophysical luminosities that have been derived through conventional redshift analyses of, e.g., gamma-ray bursts and quasars. We have calculated corrected luminosity distances within two scenarios; the standard one with a non-zero cosmological constant, and the more recently proposed ``quintessence'', with a slowly evolving energy-density component. We find luminosity corrections from +30 to -40 per cent for redshifts with z=010z=0 - 10. This finding implicates that the SCP data do not, by themselves, require a revision of the current, rather qualitative modeling of gamma-ray bursts and quasar properties.Comment: RevTeX, 4 pages, 2 postscript figures, submitted to PR

    Water cooled contactor for anode in carbon arc mechanism

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    Water cooled contactors for holding rotating carbon arc anod

    A Census of the Avifauna of the FAP 301 Project Area Addenda 1 and 2

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    Report issued on: issued July 25, 1996INHS Technical Report prepared for Illinois Department of Transportatio

    Colorectal cancer and beer drinking.

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    Evidence is presented of a significant statistical association between beer drinking and colorectal cancer, particularly rectal cancer. This finding is based on correlations between consumption and cancer mortality and between changes in consumption and changes in cancer mortality for 47 states in the United States of America. Also various secular trends, an urban-rural gradient, socioeconomic gradients and sex ratios in the United States are shown to be generally consistent with a relationship between beer consumption and colorectal cancer, particularly rectal cancer. The limitations on drawing sound aetiological inferences from such data are acknowledged. In particular, several other variables are shown to be associated with both beer drinking and colorectal cancer. Also, a discussion of previous epidemiological studies is given, and it appears there is only a limited amount of direct evidence in humans to support the statistical demographic relationships

    Patterns and Implications of Aberrant Singing Behaviors of Black-capped (Poecile atricapillus) and Carolina (Poecile carolinensis) Chickadees in Illinois

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    I studied the singing behavior of the closely related Black-capped (Poecile atricapillus) and Carolina (Poecile carolinensis) Chickadees along their range interface in central Illinois. These sibling species are parapatrically distributed from the Appalachians through the Midwest to Kansas. Where their ranges do overlap, small hybrid zones form and chickadees in these areas frequently sing aberrant songs. The majority of the songs studied were recorded 17 April-16 July 1999 in fifteen counties throughout central Illinois. I measured 8 frequency and duration characteristics of the first two notes of songs that began with two whistled notes. The averages of these characteristics for each song type at each site were classified as Black-capped Chickadee (BCC), Carolina Chickadee (CC) or intermediate on the basis of a discriminant function analysis. I developed a set of objective spectrographic criteria (OSC) that used the frequency, also duration, and basic structural characteristics of the entire song to classify them as BCC, CC, or aberrant. Based on the distribution of intermediate and aberrant song types I located four contact zones in central Illinois between these chickadees. The largest was located in Bond, Fayette, and Montgomery counties. There were smaller contact zones in Shelby, Douglas, and Champaign counties. A comparison among the distributions of BCC, CC and aberrant chickadee singing now and during a previous study in Illinois (1954-59) revealed that there has been little or no change in these two species\u27 distributions in the past 40 years. The stablility of the distributions of the song types associated with each species most likely has resulted from the fact that the factors that determined the relative distributions of these species (e.g., habitat availability) have remained stable. The greatest diversity of song types was present in the largest contact zone. I found three unique dialects within the contact zones, one each in Bond, Fayette, and Shelby counties. The Vandalia dialect (Fayette Co.) is probably at least 40 years old (Brewer 1959). I used the song types present at each site to sort the sites into eight repertoire categories based on the overall combination of song types present. Repertoire analysis revealed that bilingual singing was widespread and that individuals that sang both CC and aberrant song types that contained high frequency (\u3e6kHz) whistled notes or both BCC and songs containing only low frequency (≤5kHz) whistled notes were concentrated in specific, mutually exclusive areas. The presence of patterns in the distribution of aberrant song types and repertoire constitution in these contact zones suggests that the interaction of BCC and CC has led to the development of unique song cultures in at least some contact zones

    Defending legitimate epidemiologic research: combating Lysenko pseudoscience

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    This analysis presents a detailed defense of my epidemiologic research in the May 17, 2003 British Medical Journal that found no significant relationship between environmental tobacco smoke (ETS) and tobacco-related mortality. In order to defend the honesty and scientific integrity of my research, I have identified and addressed in a detailed manner several unethical and erroneous attacks on this research. Specifically, I have demonstrated that this research is not "fatally flawed," that I have not made "inappropriate use" of the underlying database, and that my findings agree with other United States results on this relationship. My research suggests, contrary to popular claims, that there is not a causal relationship between ETS and mortality in the U.S. responsible for 50,000 excess annual deaths, but rather there is a weak and inconsistent relationship. The popular claims tend to damage the credibility of epidemiology. In addition, I address the omission of my research from the 2006 Surgeon General's Report on Involuntary Smoking and the inclusion of it in a massive U.S. Department of Justice racketeering lawsuit. I refute erroneous statements made by powerful U.S. epidemiologists and activists about me and my research and I defend the funding used to conduct this research. Finally, I compare many aspect of ETS epidemiology in the U.S. with pseudoscience in the Soviet Union during the period of Trofim Denisovich Lysenko. Overall, this paper is intended to defend legitimate research against illegitimate criticism by those who have attempted to suppress and discredit it because it does not support their ideological and political agendas. Hopefully, this defense will help other scientists defend their legitimate research and combat "Lysenko pseudoscience.

    Is Dark Matter made up of Massive Quark Objects?

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    We suggest that dark matter is made up of massive quark objects that have survived from the Big Bang, representing the ground state of ``baryonic'' matter. Hence, there was no overall phase transition of the original quark matter, but only a split-up into smaller objects. We speculate that normal hadronic matter comes about through enforced phase transitions when such objects merge or collide, which also gives rise to the cosmic gamma-ray bursts.Comment: 8 pages Latex, no figures; to be published in the Proceedings of Dark '98, Heidelberg, July 199

    Monolithic narrow-linewidth InGaAsP semiconductor laser for coherent optical communications

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    A design for a monolithic narrow-linewidth InGaAsP diode laser has been developed using a multiple-quantum-well (MQW) extended-passive-cavity distributed-Bragg-reflector (DBR) laser design. Theoretical results indicate that this structure has the potential for a linewidth of 100 kHz or less. To realize this device, a number of the fabrication techniques required to integrate low-loss passive waveguides with active regions have been developed using a DBR laser structure. In addition, the MOCVD growth of InGaAs MQW laser structures has been developed, and threshold current densities as low as 1.6 kA/sq cm have been obtained from broad-stripe InGaAs/InGaAsP separate-confinement-heterostructure MQW lasers
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