bluuebunny/crossref_metadata_2025 huggingface dataset:
The place of pain in human experience.
Authors: Lewis G
Published: November 2008

In this last of our selection of papers from the London Medical Group Conference on Pain, Gilbert Lewis, through his experiences of living in New Guinea describes to us the various rites, rituals and uses of pain in societies other than our own. He outlines, by example, how what often seems the natural behaviour to us for helping a sufferer in fact, can make matters far worse for other peoples. Although different societies approach the problem of pain from many routes the aim of all is to relieve pain for the sufferers. If the sufferer says he feels relief then that is surely what counts.
Psychiatry as ideology in the USSR.
Authors: Bloch S
Published: November 2008

This paper was given as a talk at the Venice Biennale on 9 December 1977. It was part of a symposium on "The Freedom of Science--Problems of Science of Scientists in Eastern Europe". Dr Bloch details some of the problems of psychiatry and its vulnerability to improper use and thus the dilemmas which must ensue in day to day practice. He looks at psychiatry in the USSR and the system within which Soviet psychiatrists must work. The Communist Party and career advancement for psychiatrists would appear to be closely related and it is suggested that, in all probability, the majority of psychiatrists are as perturbed at the misuse of their profession as their Western colleagues, but act compliantly out of fear. Severe punishments have been imposed on those psychiatrists who have dared to speak out against the régime and the system as operated. Dr Bloch concludes by urging Western psychiatrists to do all they can to help their Soviet colleagues to initiate a return to an independent and automous psychiatric profession.
Bisexuality and the problem of its social acceptance.
Authors: Austin C R
Published: November 2008

Professor Austin explores four main areas in this paper. First of all he outlines the physical development of sex differentiation in the embryo. He develops this by describing the clinical manifestations of abnormality which can appear at that stage. Professor Austin points out that there are relatively few people with abnormalities and that those who do show homosexual tendencies are not noticeably different from the norm in terms of their sexual equipment and hormone levels. It is much more likely that their psychological and social development has a greater influence in differentiating them sexually. The last section of the paper is a synopsis of society's reactions to homosexuality or bisexuality which term in Professor Austin's opinion is more accurate and descriptive of the condition.
On children and proxy consent.
Authors: Blustein J
Published: November 2008

The meaning of valid proxy consent for children has recently been the subject of an important debate between Richard McCormick and Paul Ramsey on the ethics of experimenting with children. Ramsey is willing to agree with McCormick that parental consent for a child to undergo some medical procedure is valid only if parents consider what the child would consent to if he could. But beyond this, Ramsey has a fundamentally different conception of the child from McCormick, and therefore gives a very different interpretation to this standard for valid proxy consent. In Ramsey's view, McCormick's basic mistake is to think of the child as a small adult, thereby overlooking the child's peculiar vulnerabilities and needs. In particular, McCormick fails to attend to the child's needs for "preservation in life and healthful growth". In this paper, the author pursues Ramsey's suggestion that a correct analysis of valid proxy consent for children would replace the "language of consent" with the "language of need". He does this by sketching a theory of parenthood that rests on two central notions: that of primary goods, as found in the writing of John Rawls, and that of autonomy.
Teaching medical ethics: University of Edinburgh
Authors: Boyd Kenneth , Currie Colin , Thompson Ian , Tierney Alison J.
Published: November 2008

The Edinburgh Medical Group Research Project is unique in Britain. Part of its function is to experiment with teaching medical ethics both inside and outside of the Medical School. The papers which follow have been written by two full-time reseach fellows working with the Project and two of the professional advisers, one nursing and one medical. Together they give a picture of the wide scope of exerimental teaching taking place in Edinburgh and present some preliminary results from these experiments.
Quality care—commonplace or chimera
Authors: Donald B. L. , Southern R. M.
Published: November 2008

Publicity for (and laterly increased economic stringency which makes more likely), failures of care in the NHS engender concern for care quality while its assurance remains the subject of a fragmented and unhelpful literature. A selective attempt is made to examine some underlying principles by posing and answering three questions. What is the quality of care? What basic principles must be followed in defining `standards'? How then may quality be assured?

Any definition of care must be multi-faceted and in common use pervaded with the patients' pre-occupation with a search for cures. Nevertheless, it is argued that there are gains in restricting the technical use of the term `care' to those systematic processes of health services and their culture which impinge on the personal experience of patients and which fashion their response.

In contemporary society care ought to be designed to restore and enhance the independence, dignity and choice of the patient. Although there is a contrary tendency to abandon problems of care to the professionals, standards for care should be judged ultimately not from the specialised professional but from the viewpoint of lay people whose behaviour in the outside world fashions those norms by which independence, dignity and choice are judged.

A number of difficulties in identifying and securing improvements in care are discussed. In particular, it is argued that such is the interdependence of the style of management of an institution and the style of care it provides that enforcement of high quality care is likley to be a contradiction in terms. Only trained and sensitive staff can act intuitively and pre-emptively to prevent even incipient deterioration in care. They cannot carefully foster at all times the independence and dignity of their patients unless they are treated in a similar way as professional employees.

As an initial step in improving the quality of care a simple start is urged upon implementing an inventory of checks. These are designed to establish the identification and operation of health care policies and practices which give appropriate recognition to the characteristics of care that patients and public expect, coming as they do from a lay rather than professional world. The article concludes with an appropriate inventory of questions to be put to professionals by those laymen who are increasingly imported into health care management through community representation (in CHCs) and staff participation (in joint consultation) and whose interest and concern should be harnessed appropriately.
A clinical model for decision-making
Authors: Martin Richard M
Published: November 2008

Richard Martin's aim in this paper is to present a critical method of making ethical decisions in a medical context. He feels that such a reflective method provides the best means of making the appropriate decisions in given situations. It is based on Dr Martin's experience in applying ethical theory while collaborating with physicians in the daily course of clinical practice. Through his giving of a functional definition of medical ethics, his descriptions of an analytical model, the significance of values for clinical decision-making and the advocacy role of medical ethicists and their relationships with clinicians, Richard Martin sets out his own value-intention as regards an ideal decision process. He stresses that his argument is of particular importance to his fellow ethicists who should continuously and vigorously examine the creative interaction of faith and fact in their own inquiry and action. Dr Martin concludes by stating that physicians and ethicists can work together to accomplish their common aim, which is, of course, the health and well-being of the patient.
When consent is unbearable: an alternative case analysis.
Authors: Agich G J
Published: November 2008

Dr Agich takes up a previous difficult case related by Dr Kottow in an earlier issue of the Journal. He analyses the three ethical problems as presented in the case and offers his own opinion of it as well as his own conclusions with regard to the medical ethical aspects of it. Unlike Dr Kottow, Dr Agich's reading of the case indicates that the application of the principle of informed consent does not rule out ethical decisions for the physician, but emphasizes the relevance of ethical analysis beyond the issue of informed consent.
Deciding the care of severely malformed or dying infants.
Authors: Campbell A G
Published: November 2008

Suffering patients (when able), grieving families and compassionate physicians have always sought the least detrimental alternative while deciding care in the face of tragedy. Modern medical technology has brought great benefits to patients but has blurred traditional concepts of life and death and created new dilemmas for practising doctors. While this technology has given doctors great control over living and dying, their dominance in critical decision making is being challenged. More and more their decisions are liable to public and legal scrutiny, intense publicity by the news media and exploitation by lobbyists with opposing aims. Increasing pressure of this kind may deflect the physician form his primary responsibility to patients and their families. For infants with gross malformations or a distressing terminal illness we believe that the parents and their doctors must be allowed primary decisional power even if the chosen course of action involves the death of the infant. Choices for death should be permitted but only after suitable family and professional consultation. Some general guidelines are suggested. As these situations are so varied and so complex, much latitude in decision-making should be expected and tolerated.
The faces of death
Authors: Popa G , Hanganu Ecaterina
Published: November 2008

The individual's reaction to imminent death depends on his concept of the existential meaning of death.

There are two main, but opposing, concepts, one positive and the other tragic. The first sees death as a transition to another mode of being. Within that three main modalities are to be distinguished, in which is considered either as an element in the cosmic harmony, the reintegration of the individual into the universal (the `Tagorian' mode); or secondly the possibility of man's external existence through his transfer, together with his entire physical and psychological apparatus, to a realm of legend (the `Mioritic' mode); or thirdly the culmination of life, the moment of maximum existential concentration overflowing into the universe and encircling it (the `Rilkian' mode).

The second concept, the tragic concept, sees death either as a desired solution, which puts an end to the nothingness of life (the `Tracklian' mode); or as a nonsense, as an absurd injustice of nature (the `common' mode); or as a necessity of which we do not know the meaning, a dialectical moment of eternal change (the `Stoic' mode).

The psychological care of the dying involves identification with the patient's concept of death, in order to maintain his morale and possibly diminish his terror of death. The doctor must therefore be a good psychologist and a genuine philosopher, in the strictest sense of the word.
The teaching of medical ethics in the Federal Republic of Germany.
Authors: Seidler E
Published: November 2008

Eduard Seidler sets his discussion of the teaching of medical ethics in the Federal Republic of Germany against an historical background. Immediately after the Second World War the freshness of the memory of the 'Nuremberg Medical Trials' influenced the way in which moral dilemmas were treated in Germany. At the present time no systematic instruction in medical ethics is provided in either undergraduate or postgraduate or continuing medical education. As a result of this, an inquiry was set up in 1977/78. Questionnaires were sent out with a view to collecting information on how subjects referring to medical ethics are treated during medical training. The inquiry showed that no special discipline can claim to be the only competent one for medical ethics, but that everyone has something to contribute. Dr Seidler concludes by stating that basic curricula related to the problems of medical ethics would have to be developed and should be carried on continuously within the training programme.
The natural history of violence.
Authors: Russell C , Russell W M
Published: November 2008

In the past, human violence was associated with food shortage, but recently it has increased even in relatively well-fed societies. The reason appears from studies of monkeys under relaxed, spacious conditions and under crowding stress. Uncrowded monkeys have unaggressive leaders, rarely quarrel, and protect females and young. Crowded monkeys (even well-fed) have brutal bosses, often quarrel, and wound and kill each other, including females and young. Crowding has similar behaviour effects on other mammals, with physiological disturbances including greater susceptibility to infections. All this appears to be a regular response to overpopulation, reducing the population before it has depleted its natural resources. Human beings, like monkeys and other mammals, need ample space, and become more violent when crowded. Human history is marked by population cycles: population outgrows resources, the resulting violence, stress and disease mortality cuts down the population, leading to a relief period of social and cultural progress, till renewed population growth produces the next crisis. The modern population crisis is world-wide, and explains the increase of violence even in well-fed societies. The solution to the problem of violence is to substitute voluntary birth control for involuntary death control, and bring about relaxed conditions for a reduced world population.
Special features of general practice (primary care) and ethical implications.
Authors: Fry J
Published: November 2008

In all systems of health care there are certain essential levels of care and service. These take the form of self-care within the family unit; primary professional care by general medical nursing or social practitioners within a local neighbourhood; general specialist care in a district and super-specialist care in a region. Each of these has its own special roles and responsibilities and each is considered in this paper.
The hospital as a place of pain.
Authors: Vere D W
Published: November 2008

This paper was first presented at the London Medical Group's Annual Conference entitled Death: the last taboo held in February 1980. Dr Vere comments on the evidence of research done by him and his colleagues on the pain and discomfort suffered by patients who are dying and are in hospital. He contrasts this with the situation in hospices, analyses the differences, and attributes much of the unnecessary pain suffered in hospitals to attitudes of staff, as well as to a reluctance by relatives to allow patients with terminal pain to die at home. He deprecates the tendency in hospitals to separate 'curing' and 'caring' and suggests that sometimes the best help involves 'doing' less, not more.
Ethical considerations of psychosurgery: the unhappy legacy of the pre-frontal lobotomy
Authors: Gostin Larry O
Published: November 2008

There is no subject at the interface of law, psychiatry and medical ethics which is more controversial than psychosurgery. The divergent views of the treatment begin with its definition. The World Health Organisation1and others2define psychosurgery as the selective surgical removal or destruction of nerve pathways or normal brain tissue with a view to influencing behaviour. However, proponents of psychosurgery demur on the basis that the `modern' treatment is concerned predominantly with emotional illness, without any specific effect upon behaviour. The alternative definition offered is `the surgical treatment of certain psychiatric illnesses by means of localised lesions placed in specific cerebral sites.3

It is difficult entirely to accept this definition because, as examined below, scientific psychiatry is not yet in a position to directly treat psychiatric illness solely through surgical intervention. There is no reliable theoretical relationship between particular cerebral sites (which are normal and healthy) and an identifiable psychiatric illness or symptomatology. Given this state of psychiatric understanding, it is misleading to suggest fine distinctions between generalised alteration of behaviour or mood and treatment of an illness. Highly divergent practices and theories (relating to the multiplicity of conditions treated, surgical methods adopted and areas of the brain operated upon) further undermine exaggerated claims that psychosurgery can scientifically `treat' specific illness through precise surgical intervention. Nonetheless, contemporary psychosurgery does not contain quite the same `broadbrush' approach of its ancestors and it can lay some legitimate claim as an effective empirical treatment in narrowly limited circumstances. Major ethical problems still, however, arise and these will be discussed in this article.
Ethical aspects of plans to combat Huntington's chorea
Authors: Brackenridge C J
Published: November 2008

Consideration is given to some strategies to combat Huntington's disease in the absence of treatment to arrest its progress. Ethical issues for tests such as levodopa loading, to provoke symptoms prematurely in carriers of the gene, are compared with those associated with schemes for delaying the onset of disease. The major drawback of these designs is the uncertainty that prodromal symptoms may be extended unduly and the severity of deferred symptoms worsened. Some attention is also given to the possible use of post-onset plans to reduce illness severity and prolong survival. It is concluded that the characteristics of persons less prone to undesirable consequences of onset-delay should be adequately investigated before attempting to implement such schedules as a practical measure.
CURSIVE WORD RECOGNITION BASED ON INTERACTIVE ACTIVATION AND EARLY VISUAL PROCESSING MODELS
Authors: RUIZ-PINALES JOSE , JAIME-RIVAS RENE , LECOLINET ERIC , CASTRO-BLEDA MARIA JOSE
Published: November 2008

We present an off-line cursive word recognition system based completely on neural networks: reading models and models of early visual processing. The first stage (normalization) preprocesses the input image in order to reduce letter position uncertainty; the second stage (feature extraction) is based on the feedforward model of orientation selectivity; the third stage (letter pre-recognition) is based on a convolutional neural network, and the last stage (word recognition) is based on the interactive activation model.
PORTFOLIOS WITH DEADLINES FOR BACKTRACKING SEARCH
Authors: WU HUAYUE , VAN BEEK PETER
Published: November 2008

Backtracking search is often the method of choice for solving constraint satisfaction and propositional satisfiability problems. Previous studies have shown that portfolios of backtracking algorithms — a selection of one or more algorithms plus a schedule for executing the algorithms — can dramatically improve performance on some instances. In this paper, we consider a setting that often arises in practice where the instances to be solved arise over time, the instances all belong to some class of problem instances, and a limit or deadline is placed on the computational resources that can be consumed in solving any instance. For such a scenario, we present a simple scheme for learning a good portfolio of backtracking algorithms from a small sample of instances. We demonstrate the effectiveness of our approach through an extensive empirical evaluation using two testbeds: real-world instruction scheduling problems and the widely used quasigroup completion problems.
USING KNOWLEDGE REPRESENTATION FOR PERCEPTUAL ANCHORING IN A ROBOTIC SYSTEM
Authors: LOUTFI AMY , CORADESCHI SILVIA , DAOUTIS MARIOS , MELCHERT JONAS
Published: November 2008

In this work we introduce symbolic knowledge representation and reasoning capabilities to enrich perceptual anchoring. The idea that encompasses perceptual anchoring is the creation and maintenance of a connection between the symbolic and perceptual description that refer to the same object in the environment. In this work we further extend the symbolic layer by combining a knowledge representation and reasoning (KRR) system with the anchoring module to exploit a knowledge inference mechanisms. We implemented a prototype of this novel approach to explore through initial experimentation the advantages of integrating a symbolic knowledge system to the anchoring framework in the context of an intelligent home. Our results show that using the KRR we are better able to cope with ambiguities in the anchoring module through exploitation of human robot interaction.
APPLYING SIMILARITY MEASURES FOR AUTOMATIC LEMMATIZATION: A CASE STUDY FOR MODERN GREEK AND ENGLISH
Authors: LYRAS DIMITRIOS P. , SGARBAS KYRIAKOS N. , FAKOTAKIS NIKOLAOS D.
Published: November 2008

This paper addresses the problem of automatic induction of the normalized form (lemma) of regular and mildly irregular words with no direct supervision using language-independent algorithms. More specifically, two string distance metric models (i.e. the Levenshtein Edit Distance algorithm and the Dice Coefficient similarity measure) were employed in order to deal with the automatic word lemmatization task by combining two alignment models based on the string similarity and the most frequent inflectional suffixes. The performance of the proposed model has been evaluated quantitatively and qualitatively. Experiments were performed for the Modern Greek and English languages and the results, which are set within the state-of-the-art, have showed that the proposed model is robust (for a variety of languages) and computationally efficient. The proposed model may be useful as a pre-processing tool to various language engineering and text mining applications such as spell-checkers, electronic dictionaries, morphological analyzers etc.
GAMMA-RAY BURSTS AS VHE-UHE SOURCES
Authors: MÉSZÁROS PETER
Published: November 2008

Gamma-ray bursts are capable of accelerating cosmic rays up to GZK energies Ep ~ 1020 eV, which can lead to a flux at Earth comparable to that observed by large EAS arrays such as Auger. The semi-relativistic outflows inferred in GRB-related hypernovae are also likely sources of somewhat lower energy cosmic rays. Leptonic processes, such as synchrotron and inverse Compton, as well as hadronic processes, can lead to GeV-TeV gamma-rays measurable by GLAST, AGILE, or ACTs, providing useful probes of the burst physics and model parameters. Photo-meson interactions also produce neutrinos at energies ranging from sub-TeV to EeV, which will be probed with forthcoming experiments such as IceCube, ANITA and KM3NeT. This would provide information about the fundamental interaction physics, the acceleration mechanism, the nature of the sources and their environment.
THE CASE FOR NON-BARYONIC ENERGY AS THE PRIMARY OUTPUT OF GRBs
Authors: EICHLER D.
Published: November 2008

The evidence is reviewed that the primary form of energy that escapes to infinity from gamma-ray bursts (GRBs) is gamma-rays, and/or Poynting flux, and that the kinetic energy in ultrarelativistic baryons is a secondary component resulting from acceleration of baryons by radiation pressure near or beyond the photosphere. This could account for several observed characteristics of observed GRB spectra and light curves, such as the typical peak photon energy, the correlation of this peak with apparent GRB energy, and the profiles and spectral lagging of GRB subpulses.
INTEGRAL CONSTRAINTS ON GAMMA-RAY BURST POLARIZATION AND ON THE POPULATION OF NEARBY, LOW-LUMINOSITY BURSTS
Authors: HANLON L. , FOLEY S. , MCGLYNN S. , MCBREEN B. , FRENCH J. , MELADY G. , McBREEN S. , DEAN A. J. , CLARK D. J. , BIRD A. J. , WILLIS D.
Published: November 2008

The ESA γ-ray astronomy satellite INTEGRAL localized 46 gamma-ray bursts between October 2002 and July 2007. Spectral lags have been determined from the burst time profiles for about half the sample, despite the extreme faintness of many INTEGRAL bursts. INTEGRAL's sensitivity across the energy range of interest for the prompt burst emission allows us to investigate the hypothesis of a low-luminosity, nearby population of bursts. The azimuthal distribution of double-scatter events in SPI's germanium detectors, in conjunction with a sophisticated spacecraft and instrument mass model, have been used to place limits on the percentage of polarization in the prompt emission of the brightest INTEGRAL burst, GRB 041219a.
INVESTIGATION OF ELEMENT ABUNDANCES IN THE SURROUNDINGS OF GRB AFTERGLOWS
Authors: SIMIĆ S. , POPOVIĆ L. Č.
Published: November 2008

In the case of high energy collimated outflows it is important to know the density and structure of material through which jets propagate. Here we present a simple study of the environment of GRBs where the relativistic ejecta travel during the event. We use observed spectral lines in the afterglow of gamma-ray bursts and by constructing the curve of growth for most redshifted lines, we extract the column densities and Doppler parameter. This can give us the overall picture of abundances in the vicinity of GRBs. Also, we compare this result with the spectral lines with lower redshift to examine the dependence of elemental abundances on the distance from GRB event.
TESTING A NEW LUMINOSITY/REDSHIFT ESTIMATOR OF GRBs
Authors: ZHANG ZHI-BIN , XIE GUANG-ZHONG , CHOI CHUL-SUNG
Published: November 2008

Using a generalized method, we have tested an estimator of luminosity/redshift proposed by Zhang et al. (2006a), in which relative spectral lag (RSL) is tightly related with luminosity and redshift, respectively. The derived luminosities from the new estimator are found to be comparable with the observed ones. For two different GRB samples, we have examined that there are no outliers violated the luminosity relation within 3 σ confidence level. Several potential outliers for other luminosity relations are otherwise found to match the estimator well. These results suggest that the luminosity/redshift relation could be a potential tool for cosmological studies.
HIGH ENERGY NEUTRINOS FROM ACCELERATORS OF COSMIC RAY NUCLEI
Authors: TAYLOR ANDREW M.
Published: November 2008

Ongoing experimental efforts to detect cosmic sources of high energy neutrinos are guided by the expectation that astrophysical accelerators of cosmic ray protons also generate high energy neutrinos through their interactions with ambient matter and/or photons. However the predicted neutrino flux is reduced if cosmic ray sources accelerate not only protons but also a significant number of heavier nuclei, as is indicated by recent air shower data. I consider two plausible extragalactic class of sources, active galactic nuclei and gamma-ray bursts, and demand consistency with the observed cosmic ray composition and energy spectrum at Earth after allowing for propagation through intergalactic radiation fields. This allows me to calculate the degree of photo-disintegration and pion production expected to occur in these sources, and hence the neutrino fluxes from them.
UNIQUE TeV FLARES OF PKS 2155-304 IN JULY 2006
Authors:   On behalf of the H.E.S.S. Collaboration, BÜHLER ROLF
Published: November 2008

The high-frequency-peaked BL Lac PKS 2155-304 is one of the brightest and best-studied VHE gamma-ray sources in the southern hemisphere. Since 2002, the High Energy Stereoscopic System (H.E.S.S.) has monitored this source and found it to be in an unusually high state in July 2006. On the nights of 28 and 30 July, two major outbursts occurred, with peak fluxes ~ 80 times the usual values and well-resolved structures varying on time scales of ~ 200 s. Here, we report on spectral variability studies of VHE data of the first flare and show first results of the H.E.S.S. observations during the second flare night.
THE SPECTRAL SEQUENCE OF BLAZARS — STATUS AND PERSPECTIVES
Authors: MARASCHI L. , GHISELLINI G. , TAVECCHIO F. , FOSCHINI L. , SAMBRUNA R. M.
Published: November 2008

The present status of the blazar spectral sequence is discussed, including new findings about blazars selected with different criteria than the original complete radio-samples. Despite extensive searches of blazars "breaking" the sequence, the original idea proposed 10 years ago still seems to hold. On the other hand, the forthcoming launch of the GLAST satellite will provide a new selection band for blazars and blazar related populations as well as fantastic progress on the spectra and variability behaviour of presently known blazars. The order of magnitude increase in sensitivity of GLAST will allow detection of γ-rays from jets with lower power and/or lower beaming factor, thus sampling a much wider population.
SUZAKU VIEW OF POWERFUL GAMMA-RAY QUASARS
Authors: KATAOKA JUN
Published: November 2008

We present the results from multiwavelength campaigns of three powerful gamma-ray quasars, PKS 1510-089, RBS 315 and Swift J0746.3+2548, recently organized with Suzaku. The Suzaku observation provided one of the highest S/N X-ray spectra ever reported between 0.3 and 50 keV. For these quasars, the X-ray spectrum is well represented by an extremely hard power-law with photon index Γ ≃ 1.2, but is augmented by an additional soft component apparently below 1 keV for PKS 1510-089, whereas a strong deficit of soft photons is observed in RBS 315. We model the broadband spectra of these powerful quasars and argue that the power of the jet is dominated by protons but with the number of electrons/positrons exceeding the number of protons by a factor ≃ 10. We also argue that an extremely hard X-ray spectra may result from a double power-law form of the injected electrons, with the break energy γ br ≃ 1000 corresponding to the anticipated threshold of diffusive shock acceleration.
EMISSION AND POWER OF BLAZAR JETS
Authors: GHISELLINI GABRIELE
Published: November 2008

Through the modelling of the spectral energy distribution of blazars, we can infer the physical parameters required to originate the flux we see. Then we can estimate the power of blazar jets in the form of matter and fields. These estimates are rather robust for all classes of blazars, although they are in part dependent on the chosen model (i.e. leptonic rather than hadronic). The indication is that, in almost all cases, the carried Poynting flux is not dominant, while protons should carry most of the power. In emission line blazars the jet has a comparable, and often larger, power than the luminosity of the accretion disk. This is even more true for line–less BL Lacs. If the jet is structured at the sub–pc scale, with a fast spine surrounded by a slower layer, then one component sees the radiation of the other boosted, and this interplay enhances the inverse Compton flux of both. Since the layer emission is less beamed, it can be seen also at large viewing angles, making radio-galaxies very interesting GLAST candidates. Such structures need not be stable components, and can form and disappear rapidly. Ultrafast TeV variability is challenging all existing models, suggesting that at least parts of the jets are moving with large bulk Lorentz factors and at extremely small viewing angles. However, these fast "bullets" are not necessarily challenging our main ideas about the energetics and the composition of the bulk of the jet.
THE WEBT CAMPAIGN ON 3C279 IN 2006
Authors: BÖTTCHER M.
Published: November 2008

The quasar 3C 279 was the target of an extensive multiwavelength monitoring campaign from January through April 2006, including an optical-IR-radio Whole Earth Blazar Telescope (WEBT) campaign and Target of Opportunity X-ray and soft γ-ray observations with Chandra and INTEGRAL in mid-January 2006, with additional X-ray coverage by RXTE and Swift XRT as well as independent very-high-energy (VHE) γ-ray observations by MAGIC, which led to the first-ever reported tentative detection of a quasar at VHE γ-rays. In this paper we summarize the results of the WEBT campaign.

The source exhibited substantial variability of optical flux and spectral shape, with a characteristic time scale of a few days. The variability patterns throughout the optical BVRI bands were very closely correlated with each other, while there was no obvious correlation between the optical and radio variability. In intriguing contrast to other (in particular, BL Lac type) blazars, we find a lag of shorter-wavelength behind longer-wavelength variability throughout the RVB wavelength ranges, with a time delay increasing with increasing frequency. Spectral hardening during flares appears delayed with respect to a rising optical flux. This, in combination with the very steep IR-optical continuum spectral index of αo ~ 1.5 – 2.0, may indicate a highly oblique magnetic field configuration near the base of the jet, leading to inefficient particle acceleration and a very steep electron injection spectrum. An alternative explanation through a slow (time scale of several days) acceleration mechanism would require an unusually low magnetic field of B < 0.2 G , about an order of magnitude lower than inferred from previous analyses of simultaneous SEDs of 3C 279 and other FSRQs with similar properties.
THE PARSEC-SCALE CIRCULAR POLARIZATION OF ACTIVE GALACTIC NUCLEI AT 22 AND 15 GHZ
Authors: VITRISHCHAK V. M. , GABUZDA D. C.
Published: November 2008

We present the results of parsec-scale circular polarization measurements based on Very Long Baseline Array data for a number of radio-bright, core-dominated active galactic nuclei obtained simultaneously at 22 and 15 GHz. The degrees of circular polarization mc for the VLBI core region at 15 GHz are similar to values reported earlier at this wavelength, with typical values of a few tenths of a percent. The origin of this polarization is almost certainly the conversion of linear to circular polarization during the propagation of the radiation through a magnetised plasma. We find that mc is as often higher as lower at the higher frequency, for reasons that are not clear. Our results confirm the earlier finding that the sign of the circular polarization at a given observing frequency is generally consistent across epochs separated by several years or more, suggesting stability of the magnetic field orientation in the innermost jets.
PARTICLE ACCELERATION CLOSE TO THE SUPERMASSIVE BLACK HOLE HORIZON: THE CASE OF M87
Authors: RIEGER F. M. , AHARONIAN F. A.
Published: November 2008

The radio galaxy M87 has recently been found to be a rapidly variable TeV emitting source. We analyze the implications of the observed TeV characteristics and show that it proves challenging to account for them within conventional acceleration and emission models. We discuss a new pulsar-type scenario for the origin of variable, very high energy (VHE) emission close to the central supermassive black hole and show that magneto-centrifugally accelerated electrons could efficiently Compton upscatter sub-mm ADAF disk photons to the TeV regime, leading to VHE characteristics close to those observed. This suggests, conversely, that VHE observations of highly under-luminous AGNs could provide an important diagnostic tool for probing the conditions prevalent in the inner accretion disk of these sources.
SSC SCENARIO FOR TEV EMISSION FROM NON-BLAZAR AGNs
Authors: LENAIN J.-P. , BOISSON C. , SOL H.
Published: November 2008

M 87 is the first extragalactic source detected in the TeV γ-ray domain that is not a blazar, its large scale jet not being aligned to the line of sight. We present here a multi-blob synchrotron self-Compton model accounting explicitly for large viewing angles and moderate Lorentz factors as inferred from magnetohydrodynamic simulations of jet formation, motivated by the detection of M 87 at very high energies (VHE; E > 100 GeV ). Predictions are presented for the very high-energy emission of active galactic nuclei with extended optical or X-ray jet, which could be misaligned blazars but still show some moderate beaming. We include predictions for 3C 273, Cen A and PKS 0521–36.
A TWO-STEP MECHANISM FOR PARTICLE ACCELERATION IN THE MAGNETOSPHERE OF ACCRETING BLACK HOLES
Authors: ISTOMIN YA. , SOL H.
Published: November 2008

Fast variability now observed in VHE gamma-rays from active galactic nuclei (PKS 2155–304, M87, Mkn 501) seems to require very small TeV emitting zones, even in the presence of a significant relativistic beaming. We explore the possibility to accelerate particles up to VHE energies in such small compact regions around massive black holes, taking into account the two places in the black hole surroundings where efficient acceleration can be expected during the accretion-ejection process, namely turbulent low-luminosity accretion disks and rotating magnetospheres.
COOLING OF RELATIVISTIC ELECTRONS IN TEV BLAZARS: CLUES FROM MULTIWAVELENGTH SPECTRA
Authors: SCHLICKEISER R.
Published: November 2008

In powerful cosmic nonthermal radiation sources with dominant magnetic-field self generation, the generation of magnetic fields at almost equipartition strength by relativistic plasma instabilities operates as fast as the acceleration or injection of ultra-high energy radiating electrons and hadrons in these sources. Consequently, the magnetic field strength becomes time-dependent and adjusts itself to the actual kinetic energy density of the radiating electrons in these sources. This coupling of the magnetic field and the magnetic field energy density to the kinetic energy of the radiating particles changes both the intrinsic temporal evolution of the relativistic particle energy spectrum after injection and the synchrotron and synchrotron self-Compton emissivities.
COLLIMATION AND RADIATIVE DECELERATION OF JETS IN TEV AGNs
Authors: LEVINSON A. , BROMBERG O.
Published: November 2008

We consider some implications of the rapid X-ray and TeV variability observed in M87 and the TeV blazars. We outline a model for jet focusing and demonstrate that modest radiative cooling can lead to recollimation of a relativistic jet in a nozzle having a very small cross-sectional radius. Such a configuration can produce rapid variability at large distances from the central engine and may explain recent observations of the HST-1 knot in M87. Possible applications of this model to TeV blazars are discussed. We also discuss a scenario for the very rapid TeV flares observed with H.E.S.S. and MAGIC in some blazars, that accommodates the relatively small Doppler factors inferred from radio observations.
GAMMA-RAY EMISSION OF RELATIVISTIC JETS AS A SUPERCRITICAL PROCESS
Authors: STERN B. E. , POUTANEN J.
Published: November 2008

Supercriticality of the same kind as that in a nuclear pile can take place in high-energy astrophysical objects producing a number of impressive effects. For example, it could cause an explosive release of the energy of a cloud of ultrarelativistic protons into radiation. More certainly, supercriticality should be responsible for energy dissipation of very energetic relativistic fluids such as ultrarelativistic shocks in gamma-ray bursts and jets in active galactic nuclei (AGNs). In this case, the photon breeding process operates. It is a kind of converter mechanism with the high-energy photons and e+e- pairs converting into each other via pair production and inverse Compton scattering. Under certain conditions, which should be satisfied in powerful AGNs, the photon breeding mechanism becomes supercritical: the high-energy photons breed exponentially until their feedback on the fluid changes its velocity pattern. Then the system comes to a self-adjusting near-critical steady state. Monte-Carlo simulations with detailed treatment of particle propagation and interactions demonstrate that a jet with a Lorentz factor Γ ≈ 20 can radiate away up to a half of its total energy, and for Γ = 40 the radiation efficiency can be up to 80 per cent. Outer layers of the jet decelerate down to a moderate Lorentz factor 2–4, while the spine of the jet has a final Lorentz factor in the range 10–20 independent of the initial Γ. Such sharp deceleration under the impact of radiation must cause a number of interesting phenomena such as formation of internal shocks and an early generation of turbulence.
THE SUPERCRITICAL PILE MODEL FOR GRBs: THE PROMPT TO EARLY AFTERGLOW STAGE
Authors: MASTICHIADIS A. , KAZANAS D.
Published: November 2008

The "supercritical pile" is a very economical GRB model that provides for the efficient conversion of the energy stored in the protons of a relativistic blast wave (RBW) into radiation and at the same time produces — in the prompt GRB phase, even in the absence of any particle acceleration — a spectral peak at an energy ~ 1 MeV. We extend this model to include also the evolution of the RBW Lorentz factor Γ and thus follow the spectral and temporal features of this model into the GRB early afterglow stage. One of the novel features of the present treatment is the inclusion of the feedback of the GRB produced radiation on the evolution of Γ with radius. This way one can obtain afterglow light curves with steep decays followed by a relatively flatter flux stage, as observed in a large number of bursts.
Verifying policy-based web services security
Authors: Bhargavan Karthikeyan , Fournet Cédric , Gordon Andrew D.
Published: November 2008

WS-SecurityPolicy is a declarative language for configuring web services security mechanisms. We describe a formal semantics for WS-SecurityPolicy and propose a more abstract language for specifying secure links between web services and their clients. We present the architecture and implementation of tools that (1) compile policy files from link specifications, and (2) verify by invoking a theorem prover whether a set of policy files run by any number of senders and receivers correctly implements the goals of a link specification, in spite of active attackers. Policy-driven web services implementations are prone to the usual subtle vulnerabilities associated with cryptographic protocols; our tools help prevent such vulnerabilities. We can verify policies when first compiled from link specifications, and also re-verify policies against their original goals after any modifications during deployment. Moreover, we present general security theorems for all configurations that rely on compiled policies.
XARK
Authors: Arenaz Manuel , Touriño Juan , Doallo Ramon
Published: November 2008

The recognition of program constructs that are frequently used by software developers is a powerful mechanism for optimizing and parallelizing compilers to improve the performance of the object code. The development of techniques for automatic recognition of computational kernels such as inductions, reductions and array recurrences has been an intensive research area in the scope of compiler technology during the 90's. This article presents a new compiler framework that, unlike previous techniques that focus on specific and isolated kernels, recognizes a comprehensive collection of computational kernels that appear frequently in full-scale real applications. The XARK compiler operates on top of the Gated Single Assignment (GSA) form of a high-level intermediate representation (IR) of the source code. Recognition is carried out through a demand-driven analysis of this high-level IR at two different levels. First, the dependences between the statements that compose the strongly connected components (SCCs) of the data-dependence graph of the GSA form are analyzed. As a result of this intra-SCC analysis, the computational kernels corresponding to the execution of the statements of the SCCs are recognized. Second, the dependences between statements of different SCCs are examined in order to recognize more complex kernels that result from combining simpler kernels in the same code. Overall, the XARK compiler builds a hierarchical representation of the source code as kernels and dependence relationships between those kernels. This article describes in detail the collection of computational kernels recognized by the XARK compiler. Besides, the internals of the recognition algorithms are presented. The design of the algorithms enables to extend the recognition capabilities of XARK to cope with new kernels, and provides an advanced symbolic analysis framework to run other compiler techniques on demand. Finally, extensive experiments showing the effectiveness of XARK for a collection of benchmarks from different application domains are presented. In particular, the SparsKit-II library for the manipulation of sparse matrices, the Perfect benchmarks, the SPEC CPU2000 collection and the PLTMG package for solving elliptic partial differential equations are analyzed in detail.
Dually nondeterministic functions
Authors: Morris Joseph M. , Tyrrell Malcolm
Published: November 2008

Nondeterminacy is a fundamental notion in computing. We show that it can be described by a general theory that accounts for it in the form in which it occurs in many programming contexts, among them specifications, competing agents, data refinement, abstract interpretation, imperative programming, process algebras, and recursion theory. Underpinning these applications is a theory of nondeterministic functions; we construct such a theory. The theory consists of an algebra with which practitioners can reason about nondeterministic functions, and a denotational model to establish the soundness of the theory. The model is based on the idea of free completely distributive lattices over partially ordered sets. We deduce the important properties of nondeterministic functions.
Dense Linear Algebra over Word-Size Prime Fields
Authors: Dumas Jean-Guillaume , Giorgi Pascal , Pernet Clément
Published: November 2008

In the past two decades, some major efforts have been made to reduce exact (e.g. integer, rational, polynomial) linear algebra problems to matrix multiplication in order to provide algorithms with optimal asymptotic complexity. To provide efficient implementations of such algorithms one need to be careful with the underlying arithmetic. It is well known that modular techniques such as the Chinese remainder algorithm or the
p
-adic lifting allow very good practical performance, especially when word size arithmetic is used. Therefore, finite field arithmetic becomes an important core for efficient exact linear algebra libraries. In this article, we study high performance implementations of basic linear algebra routines over word size prime fields: especially matrix multiplication; our goal being to provide an exact alternate to the numerical BLAS library. We show that this is made possible by a careful combination of numerical computations and asymptotically faster algorithms. Our kernel has several symbolic linear algebra applications enabled by diverse matrix multiplication reductions: symbolic triangularization, system solving, determinant, and matrix inverse implementations are thus studied.