Discovery of extra-terrestrial life: assessment by scales of its importance and associated risks

The Rio Scale accepted by the SETI Committee of the International Academy of Astronautics in 2002 is intended for use in evaluating the impact on society of any announcement regarding the discovery of evidence of extra-terrestrial (ET) intelligence. The Rio Scale is mathematically defined using three parameters (class of phenomenon, type of discovery and distance) and a δ factor, the assumed credibility of a claim. This paper proposes a new scale applicable to announcements alleging evidence of ET life within or outside our Solar System. The London Scale for astrobiology has mathematical structure and logic similar to the Rio Scale, and uses four parameters (life form, nature of phenomenon, type of discovery and distance) as well as a credibility factor δ to calculate a London Scale index (LSI) with values ranging from 0 to 10. The level of risk or biohazard associated with a purported discovery is evaluated independently of the LSI value and may be ranked in four categories. The combined information is intended to provide a scalar assessment of the scientific importance, validity and potential risks associated with putative evidence of ET life discovered on Earth, on nearby bodies in the Solar System or in our Galaxy.     

The detection of extra-terrestrial life and the consequences for science and society

Astronomers are now able to detect planets orbiting stars other than the Sun where life may exist, and living generations could see the signatures of extra-terrestrial life being detected. Should it turn out that we are not alone in the Universe, it will fundamentally affect how humanity understands itself--and we need to be prepared for the consequences. A Discussion Meeting held at the Royal Society in London, 6-9 Carlton House Terrace, on 25-26 January 2010, addressed not only the scientific but also the societal agenda, with presentations covering a large diversity of topics.     

Bringing human, social, and natural capital to life: practical consequences and opportunities

Capital is defined mathematically as the abstract meaning brought to life in the two phases of the development of "transferable representations," which are the legal, financial, and scientific instruments we take for granted in almost every aspect of our daily routines. The first, conceptual and gestational, and the second, parturitional and maturational, phases in the creation and development of capital are contrasted. Human, social, and natural forms of capital should be brought to life with at least the same amounts of energy and efficiency as have been invested in manufactured and liquid capital, and property. A mathematical law of living capital is stated. Two examples of well-measured human capital are offered. The paper concludes with suggestions for the ways that future research might best capitalize on the mathematical definition of capital.     

Fear, threat and efficacy in threat appeals: Message involvement as a key mediator to message acceptance

In a sample of 170 youngsters, the effect of two versions of a public service announcement (PSA) threat appeal against speeding, placed in four different contexts, on evoked fear, perceived threat (severity and probability of occurrence), perceived response efficacy and self-efficacy, message involvement and anti-speeding attitude and anti-speeding intention is investigated. Evoked fear and perceived threat and efficacy independently influence message involvement. Message involvement is a full mediator between evoked fear, perceived threat and efficacy perception on the one hand, and attitudes towards the message and behavioral intention to accept the message on the other. Speeding experience has a significantly negative impact on anti-speeding attitudes. Message and medium context threat levels and context thematic congruency have a significant effect on evoked fear and to a lesser extent on perceived threat.     

Cellular responses to low dose heavy-ion exposure in human cells

The human lymphoblastoid cell line TK6 was used to study the cellular responses after low-dose (100, 200, 500 mGy) or high-dose (3 Gy) of X rays, C (22 keV.micron-1) and Fe (1000 keV.micron-1) ion exposures. p53 protein induction in individual cells was determined by indirect immunofluorescence staining. Cell-cycle progression after heavy-ion exposure was determined by using a laser scanning cytometer. A characteristic pattern of cell-cycle progression was observed with 3 Gy exposure of Fe ions but not with 100 mGy. Similarly such a pattern with 100 mGy C ion exposure did not match that with 3 Gy. The proportion of p53-induced cells is proportional to the probability of cell being hit by a primary heavy ion. The observed low-dose effect can be reflected in the probability of a hit, although detailed nature about their energy deposition must be considered for more precise estimation of such an effect. New detection methodology must be developed for identification of heavy-ion specific cellular responses.     

贴近实际持续改进精益求精

中海集装箱运输上海有限公司诞生于航运事业大发展期.为了使企业做大做强,持续发展,2004年初,公司决定先在上海总部引进ISO 9HD00标准,并于2006年4月通过了认证机构的现场审核,取得了认证证书.     

Nanotopography: cellular responses to nanostructured materials

Several in vitro and in vivo experiments have shown that nanostructured materials, which mimic the nanometer topography of the native tissues, improve biocompatible responses, and result in better tissue integration in medical implants. Understanding various aspects of nanotopography is extremely important for better designs of these devices. In this review paper, recent progress in the fabrication, characterization, biological responses, and application of nanostructured materials are discussed. Specifically, materials such as ceramics and polymers used to manufacture nanostructured surfaces are briefly introduced. Techniques for fabrication and characterization of nanostructured materials are also explored. Cellular responses such as morphology, alignment, adhesion, proliferation, and profiles of gene expression of various cell types after their exposure to nanofeatured materials are particularly reviewed. Finally, the paper briefly discusses some application of nanostructured materials including those in biosensor and tissue engineering fields.     

Fear and danger appraisals of a road-crossing scenario: a developmental perspective

Children's actual performance of visual timing task is possibly deficient, and road-crossing training programs focusing on visual timing elements result in questionable improvement in performance. The present study focused on conceptual, rather than perceptual, examination of the visual timing elements of distance and speed, as integrated into appraisals of risks related to a traffic scenario. Preschool children, third-grade children and adults appraised pedestrian fear and danger associated with four scenarios conceptually depicted using a table-top model. Each scenario described either a child or an adult pedestrian approached by a vehicle at various distances (near/far) and speeds (slow/fast). Results suggest that whereas the adult subjects integrated the danger and fear appraisals by giving separate weights to both distance and speed concepts, preschoolers failed to properly realize the danger associated with speed, and third-graders failed to integrate both concepts in their appraisals. In addition, children seem to be unaware of their underprivileged pedestrian status compared to adult pedestrians, as evidenced by similar appraisal patterns for both pedestrian age groups. The safety implications of these findings are discussed.     

Fish responses to flow velocity and turbulence in relation to size,sex and parasite load

Riverine fish are subjected to heterogeneous flow velocities and turbulence and may use this to their advantage by selecting regions that balance energy expenditure for station holding while maximizing energy gain through feeding opportunities. This study investigated microhabitat selection by guppies Poecilia reticulata in terms of flow characteristics generated by hemisphere boulders in an open channel flume. Velocity and turbulence influenced the variation in swimming behaviour with respect to size, sex and parasite intensity. With increasing body length, fish swam further and more frequently between boulder regions. Larger guppies spent more time in the areas of high-velocity and low-turbulence regions beside the boulders, whereas smaller guppies frequented the low-velocity and high-turbulence regions directly behind the boulders. Male guppies selected the regions of low velocity, indicating possible reduced swimming ability owing to hydrodynamic drag imposed by their fins. With increasing Gyrodactylus turnbulli burden, fish spent more time in regions with moderate velocity and lowest turbulent kinetic energy which were the most spatially and temporally homogeneous in terms of velocity and turbulence. These findings highlight the importance of heterogeneous flow conditions in river channel design owing to the behavioural variability within a species in response to velocity and turbulence.     

Comparison of adaptation motifs: temporal,stochastic and spatial responses

The cells’ ability to adapt to changes in the external environment is crucial for the survival of many organisms. There are two broad classes of signalling networks that achieve perfect adaptation. Both rely on complementary regulation of the response by an external signal and an inhibitory process. In one class of systems, inhibition comes about from the response itself, closing a negative feedback (NFB) loop. In the other, the inhibition comes directly from the external signal in what is referred to as an incoherent feedforward (IFF) loop. Although both systems show adaptive behaviour to constant changes in the level of the stimulus, their response to other forms of stimuli can differ. Here the authors consider the respective response to various such disturbances, including ramp increases, removal of the stimulus and pulses. The authors also consider the effect of stochastic fluctuations in signalling that come about from the interaction of the signalling elements. Finally, the authors consider the possible effect of spatially varying signals. The authors show that both the NFB and the IFF motifs can be used to sense static spatial gradients, under a local excitation, global inhibition assumption. The results may help experimentalists develop protocols that can discriminate between the two adaptation motifs.Inspec keywords: stochastic processes, microorganisms, cellular biophysicsOther keywords: adaptation motifs, temporal responses, spatial responses, stochastic responses, signalling networks, inhibitory process, negative feedback loop, incoherent feedforward loop, stochastic fluctuation effect, spatial varying signals, IFF motifs, NFB motifs     

The beginning of human life at the laboratory: The challenges of a technological future for human reproduction

This paper analyses the underlying principles and social consequences of the increasing detachment between human reproduction and sexuality via the process of technological intervention in the biological body, with a focus on current debates in Portugal. With biomedical techno-sciences, conception has become artificial (in vivo or in vitro fertilization) and independent of the coital activity. The risks and uncertainties concerning the development of Science and Technique in the biomedical field applied to reproduction present important challenges and bring forth critical questions to future generations and to humanity as a whole. For example, gametes donation (heterologous artificial insemination) implies fulfilling some ethical principles such as informed consent, anonymity and gratuitous involvement; other possible problems include the potential development of eugenic aspirations, dilemmas arising from the commercialization of gametes, embryos and fetus or surrogate motherhood, from reproductive cloning or embryonic stem-cell research techniques. In this framework, new entities appear on the scene like gametes donors, cryopreserved embryos or rented wombs that demand new laws and governmental regulation. Therefore, it is essential to study which values the techno-sciences are actually redefining, the range of social choices towards these values and the consequences these choices have – in terms of parenthood rights and family ties, for example. In this context, the paper will reflect upon these new values and will question whether they are compatible or not with democratic principles such as autonomy, human dignity or equal rights. Building upon my post-doctoral research, I will approach this problem theoretically, using tools from the Sociology of Science and of Medicine, and through data analysis (such as reports from ethical committees, legislation and media).     

Residual life of technical systems; diagnosis, prediction and life extension

The paper presents and discusses research related to residual life of non-repairable and repairable technical systems. Diagnosis of systems and extension of residual life of technical systems are also presented and discussed.This paper concludes that research published desribing determination and extension of residual life as well as methods for diagnosis of non-repairable and repairable technical systems, is somewhat limited. Many papers have a rather pragmatic approach. The authors only describe special cases from their own plant and do not provide any explanation of a more academical nature. The other papers are mainly describing very specific applications of statistical models, leaving the more general case out of consideration. One of the main results of this paper is to point out these facts, and thereby identify the need for future research in this area.     

Variation mode and effect analysis: an application to fatigue life prediction

We present an application of the probabilistic branch of variation mode and effect analysis (VMEA) implemented as a first‐order, second‐moment reliability method. First order means that the failure function is approximated to be linear around the nominal values with respect to the main influencing variables, while second moment means that only means and variances are taken into account in the statistical procedure. We study the fatigue life of a jet engine component and aim at a safety margin that takes all sources of prediction uncertainties into account. Scatter is defined as random variation due to natural causes, such as non‐homogeneous material, geometry variation within tolerances, load variation in usage, and other uncontrolled variations. Other uncertainties are unknown systematic errors, such as model errors in the numerical calculation of fatigue life, statistical errors in estimates of parameters, and unknown usage profile. By treating also systematic errors as random variables, the whole safety margin problem is put into a common framework of second‐order statistics. The final estimated prediction variance of the logarithmic life is obtained by summing the variance contributions of all sources of scatter and other uncertainties, and it represents the total uncertainty in the life prediction. Motivated by the central limit theorem, this logarithmic life random variable may be regarded as normally distributed, which gives possibilities to calculate relevant safety margins. Copyright © 2008 John Wiley & Sons, Ltd.     

Bystander responses in three-dimensional cultures containing radiolabelled and unlabelled human cells

Research on the radiation-induced bystander effect has been carried out mainly in 2-D tissue culture systems. This study uses a 3-D model, wherein apparently normal human diploid fibroblasts (AG1522) are grown in a carbon scaffold, to investigate the induction of a G(1) checkpoint in bystander cells present alongside radiolabelled cells. Cultures were simultaneously pulse-labelled with (3)H-deoxycytidine ((3)HdC) to selectively irradiate a minor fraction of cells, and bromodeoxyuridine (BrdU) to identify the radiolabelled cells. After thorough washing of cultures, iododeoxyuridine (IdU) was administered to detect proliferating bystander cells. The cultures were harvested at various times thereafter, and cells were reacted with two monoclonal antibodies specific to IdU/BrdU or BrdU, respectively, stained with propidium iodide, and subjected to multi-parameter flow cytometry. Cell-cycle progression was followed in radiolabelled cells (BrdU(+)) that were chronically irradiated by low energy beta particles emitted by DNA-incorporated (3)H, and in unlabelled bystander cells (BrdU(-)) by a flow cytometry based cumulative labelling index assay. As expected, radiolabelled cells were delayed, in a dose-dependent manner, in G(2) and subsequently G(1). No delay occurred in progression of bystander cells through G(1), when the labelled cells were irradiated at dose rates up to 0.32 Gy h(-1).     

CECILIA,a versatile research tool for cellular responses to gravity

We describe a centrifuge designed and constructed according to current demands for a versatile instrument in cellular gravitational research, in particular protists (ciliates, flagellates). The instrument (called CECILIA,centrifuge forciliates) is suited for videomonitoring, videorecording, and quantitative evaluation of data from large numbers of swimming cells in a ground-based laboratory or in a drop tower/drop shaft under microgravity conditions. The horizontal rotating platform holds up to six 8mm-camcorders and six chambers holding the experimental cells. Under hypergravity conditions (up to 15 g) chambers can be rotated about 2 axes to adjust the swimming space at right angles or parallel to the resulting gravity vector. Evaluations of cellular responses to central acceleration — in the presence of gravitational 1 g — are used for extrapolation of cellular behaviour under hypogravity conditions. CECILIA is operated and monitored by computer using a custom-made soft-ware. Times and slopes of rising and decreasing acceleration, values and quality of steady acceleration are supervised online. CECILIA can serve as an on-ground research instrument for precursor investigations of the behaviour of ciliates and flagellates under microgravity conditions such as long-term experiments in the International Space Station.     

CECILIA, a versatile research tool for cellular responses to gravity

We describe a centrifuge designed and constructed according to current demands for a versatile instrument in cellular gravitational research, in particular protists (ciliates, flagellates). The instrument (called CECILIA,centrifuge forciliates) is suited for videomonitoring, videorecording, and quantitative evaluation of data from large numbers of swimming cells in a ground-based laboratory or in a drop tower/drop shaft under microgravity conditions. The horizontal rotating platform holds up to six 8mm-camcorders and six chambers holding the experimental cells. Under hypergravity conditions (up to 15 g) chambers can be rotated about 2 axes to adjust the swimming space at right angles or parallel to the resulting gravity vector. Evaluations of cellular responses to central acceleration — in the presence of gravitational 1 g — are used for extrapolation of cellular behaviour under hypogravity conditions. CECILIA is operated and monitored by computer using a custom-made soft-ware. Times and slopes of rising and decreasing acceleration, values and quality of steady acceleration are supervised online. CECILIA can serve as an on-ground research instrument for precursor investigations of the behaviour of ciliates and flagellates under microgravity conditions such as long-term experiments in the International Space Station.