Transfer functions for infinite-dimensional systems

In this paper, we study three definitions of the transfer function for an infinite-dimensional system. The first one defines the transfer function as the expression $C(sI-A)^{-1}B+D$. In the second definition, the transfer function is defined as the quotient of the Laplace transform of the output and input, with initial condition zero. In the third definition, we introduce the transfer function as the quotient of the input and output, when the input and output are exponentials. We show that these definitions always agree on the right-half plane bounded to the left by the growth bound of the underlying semigroup, but that they may differ elsewhere

Vampires, Viruses and Verbalisation: Bram Stoker’s Dracula as a genealogical window into fin-de-siècle science

This paper considers Bram Stoker’s novel Dracula, published in 1897, as a window into techno-scientific and sociocultural developments of the fin-de-siècle era, ranging from blood transfusion and virology up to communication technology and brain research, but focusing on the birth of psychoanalysis in 1897, the year of publication. Stoker’s literary classic heralds a new style of scientific thinking, foreshadowing important aspects of post-1900 culture. Dracula reflects a number of scientific events which surfaced in the 1890s but evolved into major research areas that are still relevant today. Rather than seeing science and literature as separate realms, moreover, Stoker’s masterpiece encourages us to address the ways in which techno-scientific and psycho- cultural developments mutually challenge and mirror one another, so that we may use his novel to deepen our understanding of emerging research practices and vice versa (Zwart 2008, 2010). Psychoanalysis plays a double role in this. It is the research field whose genealogical constellation is being studied, but at the same time (Lacanian) psychoanalysis guides my reading strategy. Dracula, the infectious, undead Vampire has become an archetypal cinematic icon and has attracted the attention of numerous scholars (Browning & Picart 2009). The vampire complex built on various folkloristic and literary sources and culminated in two famous nineteenth-century literary publications: the story The Vampyre by John Polidori (published in 1819)2 and Stoker’s version. Most of the more than 200 vampire movies released since Nosferatu (1922) are based on the latter (Skal 1990; Browning & Picart 2009; Melton 2010; Silver & Ursini 2010). Yet, rather than on the archetypal cinematic image of the Vampire, I will focus on the various scientific ideas and instruments employed by Dracula’s antagonists to overcome the threat to civilisation he represents. Although the basic storyline is well-known, I will begin with a plot summary

Scientific iconoclasm and active imagination: synthetic cells as techo-schientific mandalas

Metaphors allow us to come to terms with abstract and complex information, by comparing it to something which is structured, familiar and concrete. Although modern science is “iconoclastic”, as Gaston Bachelard phrases it, scientists are at the same time prolific producers of metaphoric images themselves. Synthetic biology is an outstanding example of a technoscientific discourse replete with metaphors, including textual metaphors such as the “Morse code” of life, the “barcode” of life and the “book” of life. This paper focuses on a different type of metaphor, however, namely on the archetypal metaphor of the mandala as a symbol of restored unity and wholeness. Notably, mandala images emerge in textual materials related to one of the new “frontiers” of contemporary technoscience, namely the building of a synthetic cell: a laboratory artefact that functions like a cell and is even able to replicate itself. The mandala symbol suggests that, after living systems have been successfully reduced to the elementary building blocks and barcodes of life, the time has now come to put these fragments together again. We can only claim to understand life, synthetic cell experts argue, if we are able to technically reproduce a fully functioning cell. This holistic turn towards the cell as a meaningful whole also requires convergence at the “subject pole”: the building of a synthetic cell as a practice of the self, representing a turn towards integration, of multiple perspectives and various forms of expertise

Next. Michael Crichton. New York: Harper Collins, 2006

Michael Crichton‟s latest novel Next (2006) is his third about genomics. Yet, whereas Jurassic Park (and its sequel The lost world) contained stories about sequencing, reconstructing and revivifying the genomes of (extinct) animals, Next analyses the impact of genomics in the biomedical sphere: its consequences for human life (health, labour, sexuality, family life). Gene patenting, and the philosophy of genetic determinism that inspired and legitimised this practice, is at the root of most of the soap-like absurdities Crichton stages in his novel

The oblique perspective: philosophical diagnostics of contemporary life sciences research

This paper indicates how continental philosophy may contribute to a diagnostics of contemporary life sciences research, as part of a “diagnostics of the present”. First, I describe various options for an oblique reading of emerging scientific discourse, bent on uncovering the basic “philosophemes” of science. Subsequently, I outline a number of radical transformations occurring both at the object-pole and at the subject-pole of the current knowledge relationship, namely the technification of the object and the anonymisation or collectivisation of the subject, under the sway of automation, ICT and big machines. Finally, I further elaborate the specificity of the oblique perspective with the help of Lacan’s theorem of the four discourses. Philosophical reflections on contemporary life sciences concur neither with a Master’s discourse, nor with university discourse, nor with what Lacan refers to as hysterical discourse, but rather with the discourse of the analyst, listening with evenly-poised attention to the scientific files in order to bring to the fore the cupido sciendi which both inspires and disrupts contemporary life sciences discourse

The Origin of OB Runaway Stars

About 20% of all massive stars in the Milky Way have unusually high velocities, the origin of which has puzzled astronomers for half a century. We argue that these velocities originate from strong gravitational interactions between single stars and binaries in the centers of star clusters. The ejecting binary forms naturally during the collapse of a young (\aplt 1\,Myr) star cluster. This model replicates the key characteristics of OB runaways in our galaxy and it explains the \apgt 100\,\Msun\, runaway stars around young star clusters, e.g. R136 and Westerlund~2. The high proportion and the distributions in mass and velocity of runaways in the Milky Way is reproduced if the majority of massive stars are born in dense and relatively low-mass (5000-10000 \Msun) clusters.Comment: to appear in Scienc