The centrality of the dead human body for teaching and research – social, cultural and ethical issues

Study of the cadaver is integral to both medical education and research, but how is cadaveric material to be obtained in the 21st-century world? Historical precedents are of little assistance, built as they are on the most unethical of practices, including body snatching and murder. This constitutes a major challenge for modern anatomy: has it been able to cast off all semblance of this unsavoury past? In this paper it is contended that the continued use of unclaimed bodies has proved problematic, ignoring as it does the fundamental ethical impetus of altruism. The use of bequeathed bodies is regarded as ethically preferable, even though cultural practices vary significantly, with the result that the availability of cadavers is uneven across societies. Recent legislation has brought the role of informed consent to the fore, and this is a welcome development. Nevertheless, immense challenges remain for anatomists, a major one being that posed by the large-scale public exhibitions of plastinated bodies, the prime exponent of which is Body Worlds. In assessing the manner in which the plastinates are displayed, those with Renaissance allusions have most in common with an educational rationale, although lacking a research ethos. The contemporary genre plastinates are the furthest removed from any traditional anatomical approach, and generally lack any teaching focus. They are also the most problematic ethically when assessed in terms of the principles of beneficence and non-maleficence. Additionally, the character of donation is changed within the context of these public exhibitions

High refractive index of melanin in shiny occipital feathers of a bird of paradise

Male Lawes's Parotia, a bird of paradise, use the highly directional reflection of the structurally colored, brilliant-silvery occipital feathers in their courtship display. As in other birds, the structural coloration is produced by ordered melanin pigmentation. The barbules of the Parotia's occipital feathers, with thickness ~3 µm, contain 6–7 layers of densely packed melanin rodlets (diameter ~0.25 µm, length ~2 µm). The effectively ~0.2 µm thick melanin layers separated by ~0.2 µm thick keratin layers create a multilayer interference reflector. Reflectance measurements yielded peak wavelengths in the near-infrared at ~1.3 µm, i.e., far outside the visible wavelength range. With the Jamin-Lebedeff interference microscopy method recently developed for pigmented media, we here determined the refractive index of the intact barbules. We thus derived the wavelength dependence of the refractive index of the barbules' melanin to be 1.7–1.8 in the visible wavelength range. Implementing the anatomical and refractive index data in an optical multilayer model, we calculated the barbules' reflectance, transmittance and absorptance spectra, thereby confirming measured spectra

Geometric quantum computation with NMR

The experimental realisation of the basic constituents of quantum information processing devices, namely fault-tolerant quantum logic gates, requires conditional quantum dynamics, in which one subsystem undergoes a coherent evolution that depends on the quantum state of another subsystem. In particular, the subsystem may acquire a conditional phase shift. Here we consider a novel scenario in which this phase is of geometric rather than dynamical origin. As the conditional geometric (Berry) phase depends only on the geometry of the path executed it is resilient to certain types of errors, and offers the potential of an intrinsically fault-tolerant way of performing quantum gates. Nuclear Magnetic Resonance (NMR) has already been used to demonstrate both simple quantum information processing and Berry's phase. Here we report an NMR experiment which implements a conditional Berry phase, and thus a controlled phase shift gate. This constitutes the first elementary geometric quantum computation.Comment: Minor additions at request of referees. 4 pages revtex including 2 figures (1 eps). Nature in pres

Complete quantum teleportation using nuclear magnetic resonance

Quantum mechanics provides spectacular new information processing abilities (Bennett 1995, Preskill 1998). One of the most unexpected is a procedure called quantum teleportation (Bennett et al 1993) that allows the quantum state of a system to be transported from one location to another, without moving through the intervening space. Partial implementations of teleportation (Bouwmeester et al 1997, Boschi et al 1998) over macroscopic distances have been achieved using optical systems, but omit the final stage of the teleportation procedure. Here we report an experimental implementation of the full quantum teleportation operation over inter-atomic distances using liquid state nuclear magnetic resonance (NMR). The inclusion of the final stage enables for the first time a teleportation implementation which may be used as a subroutine in larger quantum computations, or for quantum communication. Our experiment also demonstrates the use of quantum process tomography, a procedure to completely characterize the dynamics of a quantum system. Finally, we demonstrate a controlled exploitation of decoherence as a tool to assist in the performance of an experiment.Comment: 15 pages, 2 figures. Minor differences between this and the published versio

Discovery of a transient radiation belt at Saturn

Radiation belts have been detected in situ at five planets. Only at Earth however has any variability in their intensity been heretofore observed, in indirect response to solar eruptions and high altitude nuclear explosions. The Cassini spacecraft's MIMI/LEMMS instrument has now detected systematic radiation belt variability elsewhere. We report three sudden increases in energetic ion intensity around Saturn, in the vicinity of the moons Dione and Tethys, each lasting for several weeks, in response to interplanetary events caused by solar eruptions. However, the intensifications, which could create temporary satellite atmospheres at the aforementioned moons, were sharply restricted outside the orbit of Tethys. Unlike Earth, Saturn has almost unchanging inner ion radiation belts: due to Saturn's near-symmetrical magnetic field, Tethys and Dione inhibit inward radial transport of energetic ions, shielding the planet's main, inner radiation belt from solar wind influences

The Signs of Maize? A Reconsideration of What δ¹³C Values Say about Palaeodiet in the Andean Region

Palaeodietary isotope studies have long assumed C_4 signals in South American archaeological populations to be due to the consumption of maize (Zea mays), which in turn, underlie interpretations important social processes. We presents δ¹³C data from wild plants (n=89) from the south coast of Peru, which may have been significant in the diets of humans and animals in the past. A combination of these with previously published results from domesticates of the Andean region (n=144) brings the proportion of C_4 species likely to have contributed to the human dietary isotopic signal, whether directly or indirectly, to almost one third. This undermines the widespread assumption that maize is the only plant to contribute a C_4 signal to diets. By considering both direct and indirect routes whereby C_4 plants may have contributed to the human isotopic signal we show the need for a reassessment of how palaeodietary studies are interpreted in the Andes, and perhaps elsewhere in the Americas.LC would like to thank the AHRC, the Anthony Wilkins Fund and the Santander Universities Grant for Travel to Latin America for enabling this research. TCO would like to thank the Wellcome Trust.This is the author accepted manuscript. The final version is available from Springer via http://dx.doi.org/10.1007/s10745-012-9509-0

Dating the dead: New radiocarbon dates from the lower Ica Valley, south coast Peru

This article presents radiocarbon dates from human bone samples (n = 13) from seven pre-Columbian cemeteries in the Samaca and Ullujaya Basins of the lower Ica Valley, south coast of Peru, spanning from the end of the Early Horizon to the Inca Late Horizon. These contexts have been severely looted. Yet, in all cases, their putative dating by material culture remains is confirmed by these 14C dates. This shows that such disturbed contexts, sadly typical of the Peruvian coast, can nonetheless still yield valuable bioarchaeological and burial practice data. These dates elaborate upon an emerging picture of the absolute dating of the cultural phases of the wider south coast region, in particular casting new light on the poorly understood Middle Horizon to Late Intermediate period transition. A paucity of archaeological data for this 3-century period has been taken as evidence of some sort of environmentally or socially induced lacuna. Instead, the 14C dates presented here suggest that the basins of the lower Ica Valley were continuously occupied over this period.We thank the Ministerio de Cultural del Perú for granting permission for the fieldwork (No. 0028-2010-VMPCIC-MC) and analysis of samples for dating (No. 369-2011-VMPCIC-MC); Alberto Benavides Ganoza and the people of Samaca for facilitating fieldwork; the Arts and Humanities Research Council for LC's doctoral funding; the NERC Radiocarbon Facility for funding radiocarbon dating (grant number NF/2012/1/7 to TCO’C and LC); and Tom Higham, Diane Baker, Ingmar Unkel and Elmo Leon for their help and advice.This is the final version of the article. It first appeared from University of Arizona via http://dx.doi.org/10.2458/azu_rc.57.1834

Implementation of a Quantum Search Algorithm on a Nuclear Magnetic Resonance Quantum Computer

We demonstrate an implementation of a quantum search algorithm on a two qubit NMR quantum computer based on cytosine.Comment: Six pages, three figure