Fertility control as a means of controlling bovine tuberculosis in badger (Meles meles) populations in south-west England: predictions from a spatial stochastic simulation model

A spatial stochastic simulation model was used to assess the potential of fertility control, based on a yet-to-be-developed oral bait-delivered contraceptive directed at females, for the control of bovine tuberculosis in badger populations in south-west England. The contraceptive had a lifelong effect so that females rendered sterile in any particular year remained so for the rest of their lives. The efficacy of fertility control alone repeated annually for varying periods of time was compared with a single culling operation and integrated control involving an initial single cull followed by annually repeated fertility control. With fertility control alone, in no instance was the disease eradicated completely while a viable badger population (mean group size of at least one individual) was still maintained. Near eradication of the disease (less than 1% prevalence) combined with the survival of a minimum viable badger population was only achieved under a very limited set of conditions, either with high efficiency of control (95%) over a short time period (1-3 years) or a low efficiency of control (20%) over an intermediate time period (10-20 years). Under these conditions, it took more than 20 years for the disease to decline to such low levels. A single cull of 80% efficiency succeeded in near eradication of the disease (below 1% prevalence) after a period of 6-8 years, while still maintaining a viable badger population. Integrated strategies reduced disease prevalence more rapidly and to lower levels than culling alone, although the mean badger group size following the onset of control was smaller. Under certain integrated strategies, principally where a high initial cull (80%) was followed by fertility control over a short (1-3 year) time period, the disease could be completely eradicated while a viable badger population was maintained. However, even under the most favourable conditions of integrated control, it took on average more than 12 years following the onset of control for the disease to disappear completely from the badger population. These results show that whilst fertility control would not be a successful strategy for the control of bovine tuberculosis in badgers if used alone, it could be effective if used with culling as part of an integrated strategy. This type of integrated strategy is likely to be more effective in terms of disease eradication than a strategy employing culling alone. However, the high cost of developing a suitable fertility control agent, combined with the welfare and conservation implications, are significant factors which should be taken into account when considering its possible use as a means of controlling bovine tuberculosis in badger populations in the UK

Nanomagnetic domains of chromium deposited on vertically-aligned carbon nanotubes

The drive to create ever smaller magnetic memory devices has led to the development of new nanomagnetic domains on surfaces. This paper reports the development of nano-chromium magnetic domains obtained using electrodeposition on vertically aligned carbon nanofibers arrays. Attempts to achieve this using conventional aqueous solutions were unsuccessful even after thin nickel underlayers were applied. The use of a novel electrolyte, a deep eutectic solvent, made from choline chloride: chromium (III) chloride enabled highly conformal overcoatings of chromium on individual bare carbon nanotubes to be obtained. Very high aspect ratio metal microstructures could be obtained by this novel technology. Magnetic imaging of the coated nanoarrays showed there to be clear magnetic character to the coating when the thin coatings were applied but this disappeared when the deposits were thicker and more contiguous

Effect of neutrophil depletion on gelatinase expression, edema formation and hemorrhagic transformation after focal ischemic stroke

BACKGROUND: While gelatinase (MMP-2 and -9) activity is increased after focal ischemia/reperfusion injury in the brain, the relative contribution of neutrophils to the MMP activity and to the development of hemorrhagic transformation remains unknown. RESULTS: Anti-PMN treatment caused successful depletion of neutrophils in treated animals. There was no difference in either infarct volume or hemorrhage between control and PMN depleted animals. While there were significant increases in gelatinase (MMP-2 and MMP-9) expression and activity and edema formation associated with ischemia, neutrophil depletion failed to cause any change. CONCLUSION: The main finding of this study is that, in the absence of circulating neutrophils, MMP-2 and MMP-9 expression and activity are still up-regulated following focal cerebral ischemia. Additionally, neutrophil depletion had no influence on indicators of ischemic brain damage including edema, hemorrhage, and infarct size. These findings indicate that, at least acutely, neutrophils are not a significant contributor of gelatinase activity associated with acute neurovascular damage after stroke

TeV Mini Black Hole Decay at Future Colliders

It is generally believed that mini black holes decay by emitting elementary particles with a black body energy spectrum. The original calculation lead to the conclusion that about the 90% of the black hole mass is radiated away in the form of photons, neutrinos and light leptons, mainly electrons and muons. With the advent of String Theory, such a scenario must be updated by including new effects coming from the stringy nature of particles and interactions.By taking for granted that black holes can be produced in hadronic collisions, then their decay must take into account that: (i) we live in a D3-Brane embedded into an higher dimensional bulk spacetime; (ii) fundamental interactions, including gravity, are unified at TeV energy scale. Thus, the formal description of the Hawking radiation mechanism has to be extended to the case of more than four spacetime dimensions and include the presence of D-branes. Furthermore, unification of fundamental interactions at an energy scale many order of magnitude lower than the Planck energy implies that any kind of fundamental particle, not only leptons, is expected to be emitted. A detailed understanding of the new scenario is instrumental for optimal tuning of detectors at future colliders, where, hopefully, this exciting new physics will be tested. In this article we review higher dimensional black hole decay, considering not only the emission of particles according to Hawking mechanism, but also their near horizon QED/QCD interactions. The ultimate motivation is to build up a phenomenologically reliable scenario, allowing a clear experimental signature of the event.Comment: 22 pages, 9 figures, 4 tables; ``quick review'' for Class. and Quantum Gra

Boundary Effects in Chiral Polymer Hexatics

Boundary effects in liquid-crystalline phases can be large due to long-ranged orientational correlations. We show that the chiral hexatic phase can be locked into an apparent three-dimensional N+6 phase via such effects. Simple numerical estimates suggest that the recently discovered "polymer hexatic" may actually be this locked phase.Comment: 4 pages, RevTex, 3 included eps figure

Lift-off dynamics in a simple jumping robot

We study vertical jumping in a simple robot comprising an actuated mass-spring arrangement. The actuator frequency and phase are systematically varied to find optimal performance. Optimal jumps occur above and below (but not at) the robot's resonant frequency $f_0$. Two distinct jumping modes emerge: a simple jump which is optimal above $f_0$ is achievable with a squat maneuver, and a peculiar stutter jump which is optimal below $f_0$ is generated with a counter-movement. A simple dynamical model reveals how optimal lift-off results from non-resonant transient dynamics.Comment: 4 pages, 4 figures, Physical Review Letters, in press (2012

Structure-activity relationships of the N-terminus of calcitonin gene-related peptide:key roles of alanine-5 and threonine-6 in receptor activation

Background and purpose - The N-terminus of calcitonin gene-related peptide (CGRP) is important for receptor activation, especially the disulphide-bonded ring (residues 1-7). However, the roles of individual amino acids within this region have not been examined and so the molecular determinants of agonism are unknown. This study has examined the role of residues 1, 3-6 and 8-9, excluding Cys-2 and Cys-7. Experimental approach - CGRP derivatives were substituted with either cysteine or alanine; further residues were introduced at position 6. Their affinity was measured by radioligand binding and their efficacy by measuring cAMP production in SK-N-MC cells and ß-arrestin 2 translocation in CHO-K1 cells at the CGRP receptor. Key results - Substitution of Ala-5 by cysteine reduced affinity 270-fold and reduced efficacy for production of cAMP in SK-N-MCs. Potency at ß-arrestin translocation was reduced by 9-fold. Substitution of Thr-6 by cysteine destroyed all measurable efficacy of both cAMP and ß-arrestin responses; substitution with either alanine or serine impaired potency. Substitutions at positions 1, 4, 8 and 9 resulted in approximately 10-fold reductions in potency at both responses. Similar observations were made at a second CGRP-activated receptor, the AMY1(a) receptor. Conclusions and implications - Ala-5 and Thr-6 are key determinants of agonist activity for CGRP. Ala-5 is also very important for receptor binding. Residues outside of the 1-7 ring also contribute to agonist activity

Letters of Comment

Letters from readers in The Mythic Circle #

Strong Stability and Host Specific Bacterial Community in Faeces of Ponies

The horse, as a hindgut fermenter, is reliant on its intestinal bacterial population for efficient diet utilisation. However, sudden disturbance of this population can result in severe colic or laminitis, both of which may require euthanasia. This study therefore aimed to determine the temporal stability of the bacterial population of faecal samples from six ponies maintained on a formulated high fibre diet. Bacterial 16S rRNA terminal restriction fragment length polymorphism (TRFLP) analyses of 10 faecal samples collected from 6 ponies at regular intervals over 72 hour trial periods identified a significant pony-specific profile (P<0.001) with strong stability. Within each pony, a significantly different population was found after 11 weeks on the same diet (P<0.001) and with greater intra-individual similarity. Total short chain fatty acid (SCFA) concentration increased in all ponies, but other changes (such as bacterial population diversity measures, individual major SCFA concentration) were significant and dependent on the individual. This study is the first to report the extent of stability of microbes resident in the intestinal tract as represented with such depth and frequency of faecal sampling. In doing so, this provides a baseline from which future trials can be planned and the extent to which results may be interpreted