The Twitter float and free labour : the political economy of digital media

Nick Dyer-Witheford’s Cyber-Marx was published nearly 15 years ago, but there are continuing echoes of its dire promises today. The trends that Dyer-Witheford outlined—the growth of tech-giants in the communications field at the expense of democratic media practices and the radical shedding of jobs in the traditional mass media context—are confirmed by recent events. In November 2013, Twitter launched itself on the public share register, despite having no visible means of financial support, or even much of a business plan. The Twitter IPO tells us a lot about the economy of cyber-capitalism. Aligned to the trend of ‘technological unemployment’ is the rise of what some commentators call ‘digital serfdom’. This is not just growing unemployment, but also drastic under-employment of talented media professionals and an alarming rise in the number of media outlets that want to pay contributors in ‘exposure’, rather than in corporeal, fungible dollars and cents. This articlediscusses these trends and events in the context of the political economy of digital communication.

Activity patterns of free-ranging koalas (Phascolarctos cinereus) revealed by accelerometry

An understanding of koala activity patterns is important for measuring the behavioral response of this species to environmental change, but to date has been limited by the logistical challenges of traditional field methodologies. We addressed this knowledge gap by using tri-axial accelerometer data loggers attached to VHF radio collars to examine activity patterns of adult male and female koalas in a high-density population at Cape Otway, Victoria, Australia. Data were obtained from 27 adult koalas over two 7-d periods during the breeding season: 12 in the early-breeding season in November 2010, and 15 in the late-breeding season in January 2011. Multiple 15 minute observation blocks on each animal were used for validation of activity patterns determined from the accelerometer data loggers. Accelerometry was effective in distinguishing between inactive (sleeping, resting) and active (grooming, feeding and moving) behaviors. Koalas were more active during the early-breeding season with a higher index of movement (overall dynamic body acceleration [ODBA]) for both males and females. Koalas showed a distinct temporal pattern of behavior, with most activity occurring from mid-afternoon to early morning. Accelerometry has potential for examining fine-scale behavior of a wide range of arboreal and terrestrial species.

Carbon Nanotube Biofiber Formation in a Polymer-Free Coagulation Bath

A novel solution spinning method to produce highly conducting carbon nanotube (CNT) biofibers is reported. In this process, carbon nanotubes are dispersed using biomolecules such as hyaluronic acid, chitosan, and DNA, and these dispersions are used as spinning solutions. Unlike previous reports in which a polymer binder is used in the coagulation bath, these dispersions can be converted into fibers simply by altering the nature of the coagulation bath via pH control, use of a crosslinking agent, or use of a biomolecule-precipitating solvent system. With strength comparable to most reported CNT fibers to date, these CNT biofibers demonstrate superior electrical conductivities. Cell culture experiments are performed to investigate the cytotoxicity of these fibers. This novel fiber spinning approach could simplify methodologies for creating electrically conducting and biocompatible platforms for a variety of biomedical applications, particularly in those systems where the application of an electrical field is advantageous?for example, in directed nerve and/or muscle repair.

After Charlie: free speech and the political economy of communication

Three significant events at the start of 2015 have put freedom of speech firmly on the global agenda. The first was the carry-over from the December 2014 illegal entry to the Sony Corporation’s file servers by anonymous hackers, believed to be linked to the North Korean regime. The second was the horrible attack on journalists, editors, and cartoonists at the French satirical magazine, Charlie Hebdo on 7 January. The third was the election of leftwing anti-austerity party Syrzia in Greece on 25 January.While each event is different in scope and size, they are important to scholars of the political economy of communication because they all speak to ongoing debates about freedom of expression, freedom of speech and freedom of the press. I name each of these concepts separately because, despite popular confusion, they are not the same thing (Patching and Hirst, 2014) . Freedom of expression is the right to individual self-expression through any means; it is an inalienable human right. Freedom of speech refers to the right (and the physical ability) to utter political speech, to say what others wish to repress and to demand a voice with which to express a range of social and political thoughts. Freedom of the press is a very particular version of freedom of expression that is intimately bound with the political economy of speech and of the printing press. Freedom of the press is impossible without the press and, despite its theoretical availability to all of us, this principle is impossible to articulate without the material means (usually money) to actually deploy a printing press (or the electronic means of broadcasting and publishing).Freedom of expression is immutable; freedom of speech subject to legal, ethical and ideological restriction (for better, or worse) and freedom of the press is peculiar to bourgeois society in that it entails the freedom to own and operate a press, not the right to say or publish on a level playing field. Access to freedom of the press is determined in the marketplace and is subject to the unequal power relationships that such determination implies.It is fitting to start with the Charlie Hebdo massacre because the loss of 17 lives makes this the most chilling of the three events and demands that it be given prominence in any analysis. No lives have been lost yet because Sony’s computers were hacked and the election of Syriza has not (yet) led to mass deaths in Greece.

Identification of prey captures in Australian Fur Seals (Arctocephalus pusillus doriferus) using head-mounted accelerometers: field validation with animal-borne video cameras

This study investigated prey captures in free-ranging adult female Australian fur seals (Arctocephalus pusillus doriferus) using head-mounted 3-axis accelerometers and animal-borne video cameras. Acceleration data was used to identify individual attempted prey captures (APC), and video data were used to independently verify APC and prey types. Results demonstrated that head-mounted accelerometers could detect individual APC but were unable to distinguish among prey types (fish, cephalopod, stingray) or between successful captures and unsuccessful capture attempts. Mean detection rate (true positive rate) on individual animals in the testing subset ranged from 67-100%, and mean detection on the testing subset averaged across 4 animals ranged from 82-97%. Mean False positive (FP) rate ranged from 15-67% individually in the testing subset, and 26-59% averaged across 4 animals. Surge and sway had significantly greater detection rates, but also conversely greater FP rates compared to heave. Video data also indicated that some head movements recorded by the accelerometers were unrelated to APC and that a peak in acceleration variance did not always equate to an individual prey item. The results of the present study indicate that head-mounted accelerometers provide a complementary tool for investigating foraging behaviour in pinnipeds, but that detection and FP correction factors need to be applied for reliable field application.

Shear-free perfect fluids with a γ-law equation of state

 We investigate all shear-free perfect fluid solutions of the Einstein field equations where the pressure and energy density satisfy a (Formula presented.)-law equation of state with (Formula presented.). We prove that such a fluid is either non rotating or non expanding. As a consequence, it follows by combining our result with those of Collins and Wainwright that any such shear-free perfect fluid which models either an expand universe or a collapsing star must in fact be a Friedmann–Robertson–Walker spacetime.

Performance analysis of a field-effect-transistor based aptasensor

Prostate cancer is one of the most diagnosed cancers which leads to a considerable number of deaths due to the lack of early and sensitive detection. This paper presents an aptamer functionalized field effect (FET) based biosensor for the detection of prostate cancer. Prostate specific antigen (PSA) is considered as the biomarker for prostate cancer whose detection is confirmed by attaching aptamers onto the sensor surface. Through the modelling and numerical simulation, the paper aims to evaluate and predict the performance parameters such as sensitivity, settling time, and limit of detection (LOD) of a label-free FET based electronic biosensor. Various sensor parameters such as structure (i.e., geometry), type of the FET (e.g., nanowire FET, spherical FET, ion-selective FET, and magnetic particle) radius of the FET channel and incubation time are optimized and analyzed. In addition, concentration of analyte biomolecules, diffusion coefficients and affinity to the receptor molecules are also investigated to determine the optimize performance parameters.

Flipper strokes can predict energy expenditure and locomotion costs in free-ranging northern and Antarctic fur seals

Flipper strokes have been proposed as proxies to estimate the energy expended by marine vertebrates while foraging at sea, but this has never been validated on free-ranging otariids (fur seals and sea lions). Our goal was to investigate how well flipper strokes correlate with energy expenditure in 33 foraging northern and Antarctic fur seals equipped with accelerometers, GPS, and time-depth recorders. We concomitantly measured field metabolic rates with the doubly-labelled water method and derived activity-specific energy expenditures using fine-scale time-activity budgets for each seal. Flipper strokes were detected while diving or surface transiting using dynamic acceleration. Despite some inter-species differences in flipper stroke dynamics or frequencies, both species of fur seals spent 3.79 ± 0.39 J/kg per stroke and had a cost of transport of ~1.6-1.9 J/kg/m while diving. Also, flipper stroke counts were good predictors of energy spent while diving (R(2) = 0.76) and to a lesser extent while transiting (R(2) = 0.63). However, flipper stroke count was a poor predictor overall of total energy spent during a full foraging trip (R(2) = 0.50). Amplitude of flipper strokes (i.e., acceleration amplitude × number of strokes) predicted total energy expenditure (R(2) = 0.63) better than flipper stroke counts, but was not as accurate as other acceleration-based proxies, i.e. Overall Dynamic Body Acceleration.