Transport property analysis method for thermoelectric materials: material quality factor and the effective mass model

Thermoelectric semiconducting materials are often evaluated by their figure-of-merit, zT. However, by using zT as the metric for showing improvements, it is not immediately clear whether the improvement is from an enhancement of the inherent material property or from optimization of the carrier concentration. Here, we review the quality factor approach which allows one to separate these two contributions even without Hall measurements. We introduce practical methods that can be used without numerical integration. We discuss the underlying effective mass model behind this method and show how it can be further advanced to study complex band structures using the Seebeck effective mass. We thereby dispel the common misconception that the usefulness of effective band models is limited to single parabolic band materials.Comment: 5 pages, 3 figure

The Impact of Income on Mortality: Evidence from the Social Security Notch

There is widespread and longstanding agreement that life expectancy and income are positively correlated. However, it has proven much more difficult to establish a causal relationship since income and health are jointly determined. We use a major change in the Social Security law as exogenous variation in income to examine the impact of income on mortality in an elderly population. The legislation created a notch' in Social Security benefits based upon date of birth; those born before January 1, 1917 generally receive higher benefits than those born afterwards. We compare mortality rates after age 65 for males born in the second half of 1916 and the first half of 1917. Data from restricted-use versions of the National Mortality Detail File combined with Census data allows us to count all deaths among elderly Americans between 1979 and 1993. We find that the higher income group has a statistically significantly higher mortality rate, contradicting the previous literature. We also find that the younger cohort responded to lower incomes by increasing post-retirement work effort. These results suggest that moderate employment has beneficial health effects for the elderly.

Unrepresentative information - The case of newspaper reporting on campaign finance

This article examines evidence of sampling or statistical bias in newspaper reporting on campaign finance. We compile all stories from the five largest circulation newspapers in the United States that mention a dollar amount for campaign expenditures, contributions, or receipts from 1996 to 2000. We compare these figures to those recorded by the Federal Election Commission (FEC). The average figures reported in newspapers exceed the figures from the FEC by as much as eightfold. Press reports also focus excessively on corporate contributions and soft money, rather than on the more common types of donors-individual-and types of contributions-hard money. We further find that these biases are reflected in public perceptions of money in elections. Survey respondents overstate the amount of money raised and the share from different groups by roughly the amount found in newspapers, and better-educated people (those most likely to read newspapers) showed the greatest discrepancy between their beliefs and the facts

Artistic Conversations: Artworks and Personhood

This essay explores claims made frequently by artists, critics, and philosophers that artworks bear personifying traits. Rejecting the notion that artists possess the Pygmalion-like power to bring works of art to life, the article looks seriously at how parallels may exist between the ontological structures of the artwork and human personhood. The discussion focuses on Arthur Danto’s claim that the “artworld” itself manifests properties that are an imprint of the historical representation of the“world.” These “world” representations are implicitly embodied in the artist’s style. The “world” that is stamped on the people of a historical period entails a point of view that influences how they might act, something like the logic that guides a conversation. This “conversational” logic is also extant in the artworks that artists of a given period create. This analysis of Danto’s account of how people are connected to their world clarifies Danto’s assertions that a parallel structure of personification in the artwork and the human exists. It also explains his claims that artworks themselves appear to be in a kind of dialogue

The Imperceptibility of Style in Danto's Theory of Art: Metaphor and the Artist's Knowledge

Arthur Danto’s analytic theory of art relies on a form of artistic interpretation that requires access to the art theoretical concepts of the artworld, ‘an atmosphere of artistic theory, a knowledge of the history of art: an artworld’. Art, in what Danto refers to as post-history, has become theoretical, yet it is here contended that his explanation of the artist’s creative style lacks a theoretical dimension. This article examines Danto’s account of style in light of the role the artistic metaphor plays in the interpretation of the artwork, arguing that it is unable to account for the metaphorical power he claims is embedded within the work of art. An artist’s style issues from a unique perspective, the way an artist inhabits a specific spot in history. Though each person has such a perspective, when applied aesthetically, it is the key to the articulation of a unique historical meaning in the work of art. At the same time, artists’ knowledge of their contribution remains cut off from this perspective, for they are unaware of their self-manifestation of the historical concept of style. This article makes the case that Danto’s notion of style, based on Sartre’s notion of being-for-itself, cannot fulfil the role he allots it in his theory because, at some level, artists must apprehend their style to create a work of art capable of functioning critically as a countertext. It is only through the apprehension of their style, and dialogical activity that takes place between the artist and the beholders, that the unseen body of artworld theory is formed. Without this, when oriented to the aesthetic, style provides no concept or theory for the mind to behold. This article presents an alternative approach to style that recognizes the role of theory in the creation of metaphor, which would circumvent this problem

A microfluidic oligonucleotide synthesizer

De novo gene and genome synthesis enables the design of any sequence without the requirement of a pre-existing template as in traditional genetic engineering methods. The ability to mass produce synthetic genes holds great potential for biological research, but widespread availability of de novo DNA constructs is currently hampered by their high cost. In this work, we describe a microfluidic platform for parallel solid phase synthesis of oligonucleotides that can greatly reduce the cost of gene synthesis by reducing reagent consumption (by 100-fold) while maintaining a 100 pmol synthesis scale so there is no need for amplification before assembly. Sixteen oligonucleotides were synthesized in parallel on this platform and then successfully used in a ligation-mediated assembly method to generate DNA constructs 200 bp in length

A Habermasian Critique of Danto in Defense of Gombrich's Theory of Visual Communication

El artículo demuestra que Ernst H. Gombrich sigue siendo un autor indispensable tanto para la historia como para la teoría de las artes, pues ha superado brillantemente la crítica recibida por parte de las diferentes corrientes metodológicas de la modernidad, entra en diálogo con teóricos de la talla de Arthur Danto, y así abre nuevas perspectivas de futuro