520 research outputs found
A microlensing measurement of dark matter fractions in three lensing galaxies
Direct measurements of dark matter distributions in galaxies are currently
only possible through the use of gravitational lensing observations.
Combinations of lens modelling and stellar velocity dispersion measurements
provide the best constraints on dark matter distributions in individual
galaxies, however they can be quite complex. In this paper, we use observations
and simulations of gravitational microlensing to measure the smooth (dark)
matter mass fraction at the position of lensed images in three lens galaxies:
MG 0414+0534, SDSS J0924+0219 and Q2237+0305. The first two systems consist of
early-type lens galaxies, and both display a flux ratio anomaly in their close
image pair. Anomalies such as these suggest a high smooth matter percentage is
likely, and indeed we prefer ~50 per cent smooth matter in MG 0414+0534, and
~80 per cent in SDSS J0924+0219 at the projected locations of the lensed
images. Q2237+0305 differs somewhat in that its lensed images lie in the
central kiloparsec of the barred spiral lens galaxy, where we expect stars to
dominate the mass distribution. In this system, we find a smooth matter
percentage that is consistent with zero.Comment: 7 pages, 4 figures. Accepted for publication in Ap
Probing planetary mass dark matter in galaxies: gravitational nanolensing of multiply imaged quasars
Gravitational microlensing of planetary-mass objects (or "nanolensing", as it
has been termed) can be used to probe the distribution of mass in a galaxy that
is acting as a gravitational lens. Microlensing and nanolensing light curve
fluctuations are indicative of the mass of the compact objects within the lens,
but the size of the source is important, as large sources will smooth out a
light curve. Numerical studies have been made in the past that investigate a
range of sources sizes and masses in the lens. We extend that work in two ways
- by generating high quality maps with over a billion small objects down to a
mass of 2.5\times10-5M\odot, and by investigating the temporal properties and
observability of the nanolensing events. The system studied is a mock quasar
system similar to MG 0414+0534. We find that if variability of 0.1 mag in
amplitude can be observed, a source size of ~ 0.1 Einstein Radius (ER) would be
needed to see the effect of 2.5\times10-5M\odot masses, and larger, in the
microlensing light curve. Our investigation into the temporal properties of
nanolensing events finds that there are two scales of nanolensing that can be
observed - one due to the crossing of nanolensing caustic bands, the other due
to the crossing of nanolensing caustics themselves. The latter are very small,
having crossing times of a few days, and requiring sources of size ~ 0.0001 ER
to resolve. For sources of the size of an accretion disk, the nanolensing
caustics are slightly smoothed-out, but can be observed on time scales of a few
days. The crossing of caustic bands can be observed on times scales of about 3
months.Comment: 14 pages, 9 figures, 1 table, low-quality image
Weapon-related Cranial Lesions from Medieval and Renaissance Turin, Italy
Archaeological excavations carried out in the square around the Cathedral of S. Giovanni in Turin brought to light burials referable to the medieval and Renaissance periods. The anthropological examination of the skeletal
remains allowed to identify two skeletons from the medieval period (10th–11th centuries) and four skeletons from the Renaissance age (15th century) showing weapon-related cranial injuries. These peri mortem lesions are
indicators of interpersonal aggression and in particular of armed conflicts. The two individuals from the early
medieval period presented three traumas consisting in sharp force lesions caused by bladed weapons. As
regards the Renaissance sample, themajority of the nine peri mortem injuries were sharp force wounds, followed
by a blunt force trauma. These distribution patterns might reflect different fighting techniques, whereas the side
distribution and location of the skull trauma provide further indications on the fighting modalities. Identification of
the weapons that caused these traumas is suggested. The lack of post-cranial wounds at Piazza S. Giovanni might be explained by the greater attention paid to the head, which was the main target of attack, or by adequate protection of the body through medieval and Renaissance armours. Otherwise, the wounds in the body would have been found only in the soft tissues, with no involvement of the bones.
Despite the presence of weapon injuries, the results obtained from the study of the Renaissance sample are different from the findings of other contemporary battlefields. It is highly likely that the individuals of the
Renaissance age were not young soldiers employed in war episodes and brought back for burial in Turin after battles that had taken place elsewhere. Instead, they were probably individuals who had died in riots or in other violent city episodes, as the historical records for the Renaissance age seem to confirm
Assistance, Support and Monitoring? The Paradoxes of Mentoring Adults in the Criminal Justice System
Mentoring has recently taken centre stage as one of the primary criminal justice ‘interventions’ to reduce reoffending, having grown in popularity over the past fifteen years. Its rapid growth has been driven by claims of success within and outwith the criminal justice system, leading some to argue that it has been perceived as a silver bullet (Newburn and Shiner, 2005). This article challenges such claims on three fronts: first, mentoring is an ill-defined concept with weak theoretical foundations; second, the evidence base upon which claims of success are made is limited; and third, transferring mentoring into the coercive and punitive environment of the criminal justice system results in a departure from the very principles and values which are the basis of its usefulness elsewhere. The article utilises the findings from three empirical criminal justice research projects to question claims of widespread and effective mentoring activity with defendants and offenders, suggesting instead that ‘interventions’ described as mentoring serve as a vehicle to extend the reach of the criminal justice system. At the end of the article we suggest that desistance theory, specifically the Good Lives Model, provides a conceptual framework for taking mentoring in criminal justice forward
Distinct Binding and Immunogenic Properties of the Gonococcal Homologue of Meningococcal Factor H Binding Protein
Neisseria meningitidis is a leading cause of sepsis and meningitis. The bacterium recruits factor H (fH), a negative regulator of the complement system, to its surface via fH binding protein (fHbp), providing a mechanism to avoid complement-mediated killing. fHbp is an important antigen that elicits protective immunity against the meningococcus and has been divided into three different variant groups, V1, V2 and V3, or families A and B. However, immunisation with fHbp V1 does not result in cross-protection against V2 and V3 and vice versa. Furthermore, high affinity binding of fH could impair immune responses against fHbp. Here, we investigate a homologue of fHbp in Neisseria gonorrhoeae, designated as Gonococcal homologue of fHbp (Ghfp) which we show is a promising vaccine candidate for N. meningitidis. We demonstrate that Gfhp is not expressed on the surface of the gonococcus and, despite its high level of identity with fHbp, does not bind fH. Substitution of only two amino acids in Ghfp is sufficient to confer fH binding, while the corresponding residues in V3 fHbp are essential for high affinity fH binding. Furthermore, immune responses against Ghfp recognise V1, V2 and V3 fHbps expressed by a range of clinical isolates, and have serum bactericidal activity against N. meningitidis expressing fHbps from all variant groups
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The use of phylogeny to interpret cross-cultural patterns in plant use and guide medicinal plant discovery: an example from Pterocarpus (Leguminosae)
The study of traditional knowledge of medicinal plants has led to discoveries that have helped combat diseases and improve healthcare. However, the development of quantitative measures that can assist our quest for new medicinal plants has not greatly advanced in recent years. Phylogenetic tools have entered many scientific fields in the last two decades to provide explanatory power, but have been overlooked in ethnomedicinal studies. Several studies show that medicinal properties are not randomly distributed in plant phylogenies, suggesting that phylogeny shapes ethnobotanical use. Nevertheless, empirical studies that explicitly combine ethnobotanical and phylogenetic information are scarce.In this study, we borrowed tools from community ecology phylogenetics to quantify significance of phylogenetic signal in medicinal properties in plants and identify nodes on phylogenies with high bioscreening potential. To do this, we produced an ethnomedicinal review from extensive literature research and a multi-locus phylogenetic hypothesis for the pantropical genus Pterocarpus (Leguminosae: Papilionoideae). We demonstrate that species used to treat a certain conditions, such as malaria, are significantly phylogenetically clumped and we highlight nodes in the phylogeny that are significantly overabundant in species used to treat certain conditions. These cross-cultural patterns in ethnomedicinal usage in Pterocarpus are interpreted in the light of phylogenetic relationships.This study provides techniques that enable the application of phylogenies in bioscreening, but also sheds light on the processes that shape cross-cultural ethnomedicinal patterns. This community phylogenetic approach demonstrates that similar ethnobotanical uses can arise in parallel in different areas where related plants are available. With a vast amount of ethnomedicinal and phylogenetic information available, we predict that this field, after further refinement of the techniques, will expand into similar research areas, such as pest management or the search for bioactive plant-based compounds
The Effect of Human Factor H on Immunogenicity of Meningococcal Native Outer Membrane Vesicle Vaccines with Over-Expressed Factor H Binding Protein
The binding of human complement inhibitors to vaccine antigens in vivo could diminish their immunogenicity. A meningococcal ligand for the complement down-regulator, factor H (fH), is fH-binding protein (fHbp), which is specific for human fH. Vaccines containing recombinant fHbp or native outer membrane vesicles (NOMV) from mutant strains with over-expressed fHbp are in clinical development. In a previous study in transgenic mice, the presence of human fH impaired the immunogenicity of a recombinant fHbp vaccine. In the present study, we prepared two NOMV vaccines from mutant group B strains with over-expressed wild-type fHbp or an R41S mutant fHbp with no detectable fH binding. In wild-type mice in which mouse fH did not bind to fHbp in either vaccine, the NOMV vaccine with wild-type fHbp elicited 2-fold higher serum IgG anti-fHbp titers (P = 0.001) and 4-fold higher complement-mediated bactericidal titers against a PorA-heterologous strain than the NOMV with the mutant fHbp (P = 0.003). By adsorption, the bactericidal antibodies were shown to be directed at fHbp. In transgenic mice in which human fH bound to the wild-type fHbp but not to the R41S fHbp, the NOMV vaccine with the mutant fHbp elicited 5-fold higher serum IgG anti-fHbp titers (P = 0.002), and 19-fold higher bactericidal titers than the NOMV vaccine with wild-type fHbp (P = 0.001). Thus, in mice that differed only by the presence of human fH, the respective results with the two vaccines were opposite. The enhanced bactericidal activity elicited by the mutant fHbp vaccine in the presence of human fH far outweighed the loss of immunogenicity of the mutant protein in wild-type animals. Engineering fHbp not to bind to its cognate complement inhibitor, therefore, may increase vaccine immunogenicity in humans
Offender management in and after prison: The end of ‘end to end’?
In 2013 a joint report by the Inspectorates of Probations and Prisons in England and Wales
concluded that offender management in prisons was ‘not working’ and called for a fundamental
review. This article considers why existing arrangements have failed and draws upon theory and
research on resettlement, case management and desistance from crime, to define what a more
effective system of ‘rehabilitative resettlement’ – both inside prison and ‘through the gate’ – might
look like. It also comments on emerging proposals for radical change, including abandonment
of the ‘end to end’ model of offender management by an outside probation officer and the
development of ‘rehabilitative prisons’, in which more responsibility is placed on prisoners for
managing their own rehabilitation, and a formal motivational role is created for large numbers of
prison staff.10.1177/1748895816665435 Published in the Journal Criminology & Criminal Justice published by Sag
The not-so-Dark Ages: Ecology for human growth in medieval and early Twentieth Century Portugal as inferred from skeletal growth profiles
This study attempts to address the issue of relative living standards in Portuguese medieval and early 20th century periods. Since the growth of children provides a good measure of environmental quality for the overall population, the skeletal growth profiles of medieval Leiria and early 20th century Lisbon were compared. Results show that growth in femur length of medieval children did not differ significantly from that of early 20th century children, but after puberty medieval adolescents seem to have recovered, as they have significantly longer femora as adults. This is suggestive of greater potential for catch-up growth in medieval adolescents. We suggest that this results from distinct child labor practices, which impact differentially on the growth of Leiria and Lisbon adolescents. Work for medieval children and adolescents were related to family activities, and care and attention were provided by family members. Conversely, in early 20th century Lisbon children were more often sent to factories at around 12 years of age as an extra source of family income, where they were exploited for their labor. Since medieval and early 20th century children were stunted at an early age, greater potential for catch-up growth in medieval adolescents results from exhausting work being added to modern adolescent's burdens of disease and poor diet, when they entered the labor market. Although early 20th century Lisbon did not differ in overall unfavorable living conditions from medieval Leiria, after puberty different child labor practices may have placed modern adolescents at greater risk of undernutrition and poor growth. Am J Phys Anthropol, 2008. © 2008 Wiley-Liss, Inc
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