123 research outputs found
On the Mass and Width of the Z-boson and Other Relativistic Quasistable Particles
The ambiguity in the definition for the mass and width of relativistic
resonances is discussed, in particular for the case of the Z-boson. This
ambiguity can be removed by requiring that a resonance's width
(defined by a Breit-Wigner lineshape) and lifetime (defined by the
exponential law) always and exactly fulfill the relation .
To justify this one needs relativistic Gamow vectors which in turn define the
resonance's mass M_R as the real part of the square root of
the S-matrix pole position s_R. For the Z-boson this means that and where M_Z and
are the values reported in the particle data tables.Comment: 23 page
The Reliability of Global and Hemispheric Surface Temperature Records
The purpose of this review article is to discuss the development and associated estimation of uncertainties in the global and hemispheric surface temperature records. The review begins by detailing the groups that produce surface temperature datasets. After discussing the reasons for similarities and differences between the various products, the main issues that must be addressed when deriving accurate estimates, particularly for hemispheric and global averages, are then considered. These issues are discussed in the order of their importance for temperature records at these spatial scales: biases in SST data, particularly before the 1940s; the exposure of land-based thermometers before the development of louvred screens in the late 19th century; and urbanization effects in some regions in recent decades. The homogeneity of land-based records is also discussed; however, at these large scales it is relatively unimportant. The article concludes by illustrating hemispheric and global temperature records from the four groups that produce series in near-real time
Falsification Of The Atmospheric CO2 Greenhouse Effects Within The Frame Of Physics
The atmospheric greenhouse effect, an idea that many authors trace back to
the traditional works of Fourier (1824), Tyndall (1861), and Arrhenius (1896),
and which is still supported in global climatology, essentially describes a
fictitious mechanism, in which a planetary atmosphere acts as a heat pump
driven by an environment that is radiatively interacting with but radiatively
equilibrated to the atmospheric system. According to the second law of
thermodynamics such a planetary machine can never exist. Nevertheless, in
almost all texts of global climatology and in a widespread secondary literature
it is taken for granted that such mechanism is real and stands on a firm
scientific foundation. In this paper the popular conjecture is analyzed and the
underlying physical principles are clarified. By showing that (a) there are no
common physical laws between the warming phenomenon in glass houses and the
fictitious atmospheric greenhouse effects, (b) there are no calculations to
determine an average surface temperature of a planet, (c) the frequently
mentioned difference of 33 degrees Celsius is a meaningless number calculated
wrongly, (d) the formulas of cavity radiation are used inappropriately, (e) the
assumption of a radiative balance is unphysical, (f) thermal conductivity and
friction must not be set to zero, the atmospheric greenhouse conjecture is
falsified.Comment: 115 pages, 32 figures, 13 tables (some typos corrected
Does the history of food energy units suggest a solution to "Calorie confusion"?
The Calorie (kcal) of present U.S. food labels is similar to the original French definition of 1825. The original published source (now available on the internet) defined the Calorie as the quantity of heat needed to raise the temperature of 1 kg of water from 0 to 1°C. The Calorie originated in studies concerning fuel efficiency for the steam engine and had entered dictionaries by 1840. It was the only energy unit in English dictionaries available to W.O. Atwater in 1887 for his popular articles on food and tables of food composition. Therefore, the Calorie became the preferred unit of potential energy in nutrition science and dietetics, but was displaced when the joule, g-calorie and kcal were introduced. This article will explain the context in which Nicolas Clément-Desormes defined the original Calorie and the depth of his collaboration with Sadi Carnot. It will review the history of other energy units and show how the original Calorie was usurped during the period of international standardization. As a result, no form of the Calorie is recognized as an SI unit. It is untenable to continue to use the same word for different thermal units (g-calorie and kg-calorie) and to use different words for the same unit (Calorie and kcal). The only valid use of the Calorie is in common speech and public nutrition education. To avoid ongoing confusion, scientists should complete the transition to the joule and cease using kcal in any context
Near miss: the importance of the natural atmospheric CO2 concentration to human historical evolution
System differentiation in England: the imposition of supply and demand
This chapter describes changing state and sector policy in relation to differentiation and how it has emerged in the English HE context: specifically, the attempts to concentrate the highest qualified applicants and the most prestigious institutions in a 'premium' market segment; the significance of the growing involvement of private providers; and the rise of the ‘student-as-consumer’ and 'value for money' in recent government policy discourse (e.g. the White Papers Students at the Heart of the System (DBIS 2011a) and Success as a Knowledge Economy (DBIS 2016). The chapter situates the development of a market hierarchy (in the form of a vertical differentiation of institutions, Archer 2007) following the demise of the university-polytechnic binary system in 1992 (Further and Higher Education Act, HMSO 1992). This co-existed for several years with the institutional diversity often celebrated by the Higher Education Funding Council for England (e.g. HEFCE 1994; 2000) that can be conceptualised as the horizontal differentiation of valued types of higher education provision and provider (e.g. part-time or vocationally orientated). The introduction of market mechanisms, in various stages beginning with the 2004 Higher Education Act (DfES 2004) and the introduction of variable tuition fees, coincided with the publication of institutional league tables from 2005. Taken together, these have reinforced a hierarchical system in which all institutions and courses are henceforth differentiated only by reference to a set of criteria dominated by the entry requirements demanded, and the amount of research carried out by the institution. Given the implications of the most recent legislation – the Higher Education and Research Act (HMSO 2017) this hierarchy is likely to be matched by one signalled by tuition fee levels, as new cheaper 'challenger' institutions come to the market
Beyond equilibrium climate sensitivity
ISSN:1752-0908ISSN:1752-089
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