Catching crabs: a case study in local-scale English conservation

Wells-next-the-Sea and Cromer in Norfolk (England) both rely upon their local crab populations, since crabbing (gillying) is a major part of their tourist industry. Compared to a control site with no crabbing, crabs from Wells harbour and Cromer pier were found to have nearly six times the amount of limb damage. Crabs caught by the general public had more injuries than crabs caught in controlled conditions, suggesting the buckets in which the crabs were kept were to blame. Since there is much evidence that such injuries have negative impacts on the survival and reproductive success of the shore crab, this is taken as evidence of non-lethal injury from humans having a population-level effect on these animals. Questionnaire data demonstrated a public lack of awareness and want for information, which was then used to obtain funding to produce a leaflet campaign informing the public of how to crab responsibly. All data collected is available online at http://dx.doi.org/10.6084/m9.figshare.979288

Cyclic AMP Signaling: A Molecular Determinant of Peripheral Nerve Regeneration

Disruption of axonal integrity during injury to the peripheral nerve system (PNS) sets into motion a cascade of responses that includes inflammation, Schwann cell mobilization, and the degeneration of the nerve fibers distal to the injury site. Yet, the injured PNS differentiates itself from the injured central nervous system (CNS) in its remarkable capacity for self-recovery, which, depending upon the length and type of nerve injury, involves a series of molecular events in both the injured neuron and associated Schwann cells that leads to axon regeneration, remyelination repair, and functional restitution. Herein we discuss the essential function of the second messenger, cyclic adenosine monophosphate (cyclic AMP), in the PNS repair process, highlighting the important role the conditioning lesion paradigm has played in understanding the mechanism(s) by which cyclic AMP exerts its proregenerative action. Furthermore, we review the studies that have therapeutically targeted cyclic AMP to enhance endogenous nerve repair

The acoustic radiation impedance of a rectangular panel

This paper extends the definition of the one sided radiation impedance of a panel mounted in an infinite rigid baffle which was previously used by the authors so that it can be applied to all transverse velocity wave types on the panel rather than just to the possibly forced travelling plane transverse velocity waves considered previously by the authors. For the case of travelling plane waves on a rectangular panel with anechoic edge conditions, and for the case of standing waves on a rectangular panel with simply supported edge conditions, the equations resulting from one of the standard reductions from quadruple to double integrals are given. These double integral equations can be reduced to single integral equations, but the versions of these equations given in the literature did not always converge when used with adaptive integral routines and were sometimes slower than the double integral versions. This is because the terms in the integrands in the existing equations have singularities. Although these singularities cancel, they caused problems for the adaptive integral routines. This paper rewrites these equations in a form which removes the singularities and enables the integrals in these equations to be evaluated with adaptive integral routines. Approximate equations for the azimuthally averaged one sided radiation impedance of a rectangular panel mounted in an infinite baffle are given for all the cases considered in this paper and the values produced by these equations are compared with numerical calculations

Approximate equations for the radiation impedance of a rectangular panel

The authors have previously published approximate formulae for the average one sided specific radiation wave impedance of a finite rectangular panel mounted in a rigid infinite baffle. The panel's transverse vibration was due to a (possibly forced) two dimensional bending plane wave propagating in the panel without reflection at the edges of the panel. The average was over all the surface area of the panel and over all possible azimuthal angles of propagation direction. The radiation from waves propagating in different directions was assumed to be uncorrelated. These approximate formulae were derived from the 1982 research of Thomasson whose approximate formulae only covered the high and low frequency regions and not the mid frequency region. This paper presents more accurate versions of some of the approximate formulae. When the bending wave number is larger than the wave number of sound, the real part of the impedance is smaller than that for the case studied by Maidanik and Leppington. This is because correlated reflections are not included the case analyzed in this paper. When the bending wave number is smaller than or equals the wave number of sound, the real part of the impedance is the same for both cases

Approximate formulae for the average one sided specific radiation wave impedance of a finite rectangular panel

The authors have previously published approximate formulae for the average one sided specific radiation wave impedance of a finite rectangular panel mounted in a rigid infinite baffle. The panel's transverse vibration was due to a (possibly forced) two dimensional bending plane wave propagating in the panel without reflection at the edges of the panel. The average was over all the surface area of the panel and over all possible azimuthal angles of propagation direction. The radiation from waves propagating in different directions was assumed to be uncorrelated. These approximate formulae were derived from the 1982 research of Thomasson whose approximate formulae only covered the high and low frequency regions and not the mid frequency region. This paper presents more accurate versions of some of the approximate formulae. When the bending wave number is larger than the wave number of sound, the real part of the impedance is smaller than that for the case studied by Maidanik and Leppington. This is because correlated reflections are not included the case analyzed in this paper. When the bending wave number is smaller than or equals the wave number of sound, the real part of the impedance is the same for both cases

The average specific forced radiation wave impedance of a finite rectangular panel

The average specific forced radiation wave impedance of a finite rectangular panel is of importance for the prediction of both sound insulation and sound absorption. In 1982, Thomasson published numerical calculations of the average specific forced radiation wave impedance of a square of side length 2e for wave number k in half octave steps of ke from 0.25 to 64. Thomasson's calculations were for the case when the forced bending wave number kb was less than or equal to k. Thomasson also published approximate formulas for values of ke above and below the published results. This paper combines Thomasson's high and low frequency formulas and compares this combined formula with Thomasson's numerical calculations. The real part of the approximate formula is between 0.7 dB higher and -1 dB lower than the numerical calculations. The imaginary part of the approximate formula is between 2.3 dB higher and -2.6 dB lower than the numerical calculations. This paper also gives approximate formulas for the case when kb is greater than or equal to k. The differences are between 0.8 and -1.2 dB for the imaginary part and between 6.2 and -2.4 dB for the real part

Chronic thoracic hemisection spinal cord injury in adult rats induces a progressive decline in transmission from uninjured fibers to lumbar motoneurons

Although most spinal cord injuries are anatomically incomplete, only limited functional recovery has been observed in people and rats with partial lesions. To address why surviving fibers cannot mediate more complete recovery, we evaluated the physiological and anatomical status of spared fibers after unilateral hemisection (HX) of thoracic spinal cord in adult rats. We made intracellular and extracellular recordings at L5 (below HX) in response to electrical stimulation of contralateral white matter above (T6) and below (L1) HX. Responses from T6 displayed reduced amplitude, increased latency and elevated stimulus threshold in the fibers across from HX, beginning 1-2 weeks after HX. Ultrastructural analysis revealed demyelination of intact axons contralateral to the HX, with a time course similar to the conduction changes. Behavioral studies indicated partial recovery which arrested when conduction deficits began. These findings suggest a chronic pathological state in intact fibers and necessity for prompt treatment to minimize it

Increased antigen specific T cell numbers in the absence of altered migration or division rates as a result of mucosal cholera toxin administration

Cholera toxin (CT) is a mucosal adjuvant capable of inducing strong immune responses to co-administered antigens following oral or intranasal immunization of mice. To date, the direct effect of CT on antigen-specific CD4(+) T cell migration and proliferation profiles in vivo is not well characterized. In this study, the effect of CT on the migration pattern and proliferative responses of adoptively transferred, CD4(+) TCR transgenic T cells in orally or intranasally vaccinated mice, was analyzed by flow cytometry. GFP-expressing or CFSE-labeled OT-II lymphocytes were adoptively transferred to naïve C57BL/6 mice, and mice were subsequently vaccinated with OVA with or without CT via the oral or intranasal route. CT did not alter the migration pattern of antigen-specific T cells, regardless of the route of immunization, but increased the number of transgenic CD4(+) T cells in draining lymphoid tissue. This increase in the number of transgenic CD4(+) T cells was not due to cells undergoing more rounds of cellular division in vivo, suggesting that CT may exert an indirect adjuvant effect on CD4(+) T cells. The findings reported here suggest that CT functions as a mucosal adjuvant by increasing the number of antigen specific CD4(+) T cells independent of their migration pattern or kinetics of cellular division.Grant support was received from the National Health and Medical Research Council of Australia (NHMRC). OLW is a recipient of an R.D. Wright Career Development Award

Post-operative immune suppression is reversible with interferon gamma and independent of IL-6 pathways

Introduction The post-operative period is characterised by increased IL-6 production and clinical features of immune suppression. In vitro anti-inflammatory actions of IL-6 are mediated through suppression of interferon gamma (IFNγ) [1]. The clinical significance of IL-6 in mediating post-operative immune suppression remains unclear. Objectives To evaluate the role of IL-6 pathways in post-operative immune suppression and the reversibility of this phenomenon. Methods Patients over 45 years old undergoing elective surgery involving the gastrointestinal tract and requiring at least an overnight hospital stay were recruited. The primary outcome was hospital-acquired infection. IL-6 and IFNγ levels were assayed using ELISA preoperatively and at 24 and 48 hours. Pooled healthy control peripheral blood mononuclear cells (PBMCs) were cultured in perioperative serum and CD14+HLA-DR (mHLA-DR) geometric mean florescent intensity (MFI) measured in the presence and absence of interferon gamma (IFNγ) and IL-6 neutralising antibody. Data were analysed with non-parametric statistics. Results 119 patients were recruited and 44 (37%) developed a post-operative infection a median of 9 (IQR 5-11) days postoperatively (Figure 1). IL-6 levels increased from baseline to 24 hours postoperatively (P < 0.0001, Figure 1A) but were then unchanged between 24 and 48 hours (P = 0.06, Figure 1B). Postoperative IL-6 levels correlated with the duration of the procedure (P = 0.009). Higher preoperative IL-6 levels were observed in patients with cancer (P = 0.02). IL-6 levels at 24 (P = 0.0002) and 48 hours (P = 0.003) were associated with the later occurrence of infectious complications. This pattern remained similar after adjustment for baseline characteristics. Healthy donor PBMCs incubated with postoperative serum downregulated mHLA-DR MFI when compared with serum from baseline (n = 8, p = 0.008). Culturing in the presence of IFNγ 250IU (n = 4) prevented this decrease whereas culturing in the presence of IL-6 neutralising antibody 15ng/ml (n = 8) did not. Conclusions IL-6 levels increase following major surgery and are associated with an increased susceptibility to post-operative infections. Serum obtained from post-operative patients induces an immunosuppressive response through an IL-6 independent pathways which is reversible with IFNγ treatment