Competition between wild and captive-bred Penaeus plebejus and implications for stock enhancement

The mechanisms that drive density dependence are rarely studied in the applied context of population management. We examined the potential for competition for food and shelter and the resulting demographic density dependence to influence how well populations of the eastern king prawn Penaeus plebejus Hess can recover following marine stock enhancement programmes in which captive-bred juveniles are released into the wild. Specifically, manipulative laboratory experiments were used to quantify the differential effects of competition for food and competition for shelter on survival of wild and captive-bred P. plebejus as densities were increased and as each category of P. plebejus (wild or captive-bred) was supplemented with the alternate category. Increasing population densities when food and shelter were limited lowered survival for both categories. When food was limited, survival of both categories was unaffected by addition of the alternative category. Adding wild P. plebejus to their captive-bred counterparts when shelter was limited under laboratory conditions resulted in significantly higher mortality in captive-bred individuals. In contrast, adding captive-bred P. plebejus to wild individuals under these conditions did not affect wild P. plebejus. We conclude that if the current results can be extended to wild conditions, competition for shelter may lead to the loss of captive-bred P. plebejus, thereby reducing the intended outcomes of stock enhancement. This highlights the importance of investigating interactions between wild and captive-bred animals prior to stock enhancement to predict long-term outcomes and identify situations where stock enhancement could be an effective response to the loss of populations or recruitment limitation

Reconceptualizing international mindedness in and for a posthuman world

This article offers a novel foray into international mindedness and posthuman theory. International mindedness underpins the International Baccalaureate’s aim to achieve a better and more peaceful world. However, in a global context of planetary emergency and widening inequalities, it seems imperative to rethink international mindedness within a posthumanist frame, that is, beyond anthropocentric notions of education that privilege human exceptionalism. The reconceptualization of international mindedness as relational becoming is illuminated through five theoretical propositions which are illustrated empirically using ‘material moments’. Relational becoming rejects mind and body binaries, affirms nonhuman–human assemblages, enables distributed agency, enacts ethics of response-ability and engages with past and present entanglements. ‘Posthumanizing’ international mindedness, through the concept of relational becoming, prompts more nuanced insights into educational privilege, nationstates, globalism and enduring colonialist inheritances

The epidemiology of cataract: a review of the literature

Cataract is a major cause of blindness, accounting for nearly half of all blindness worldwide. Epidemiological research provides the principles and methods to assess the extent of cataract, and supplies the necessary information for policy planning. Obtaining accurate epidemiological data on cataract is essential to ascertain and estimate the cost of primary and secondary eye health care needs. Determining risk factors is also necessary to reduce the economic and social repercussions associated with the disease. The following paper presents a review of the epidemiology of cataract in the middle to elderly age group

An overview of systematic reviews in medical education and a focused review in prescribing

Background: Tertiary reviews (review of reviews) in medical education tend to focus on doctors, continuing education and professional practice. This paper provides a tertiary review of all areas of medical education at all levels. An in-depth focus on prescribing is included. Methods and results: A systematic search using the keywords ‘medical education’ AND (‘systematic review’ OR ‘meta-analysis’) yielded 187 reviews. Reviews were coded by intervention, curriculum/theme, participants and outcomes, creating a systematic map. The most popular interventions and curriculum were simulation (9%) and prescribing (7%), respectively. Most reviews included multiple participant types (68%) and sought patient/health outcomes (64%). Twelve prescribing reviews included in the in-depth review found active educational strategies more effective than passive strategies. Discussion: The systematic map highlights topics and interventions, but further research should explore the cost-effectiveness of the reviews themselves. Prescribing reviews tend to focus on doctors; more research into the acquisition of prescribing skills by students/junior doctors is required

HPV typing of vulvovaginal condylomata in children

No Abstract

Construction of simplified design <i>p-y</i> curves for liquefied soils

In practice, laterally loaded piles are most often modelled using a ‘Beam-on-Nonlinear-Winkler-Foundation’ (BNWF) approach. While well calibrated p-y curves exist for non-liquefied soils (e.g. soft clay and sands), the profession still lacks reliable p-y curves for liquefied soils. In fact, the latter should be consistent with the observed strain-hardening behaviour exhibited by liquefied samples in both element and physical model tests. It is recognised that this unusual strain-hardening behaviour is induced by the tendency of the liquefied soil to dilate upon undrained shearing, which ultimately results in a gradual decrease of excess pore pressure and consequent increase in stiffness and strength. The aim of this paper is twofold. First it proposes an easy-to-use empirical model for constructing stress-strain relationships for liquefied soils. This only requires three soil parameters which can be conveniently determined by means of laboratory tests, such as a cyclic triaxial and cyclic simple shear tests. Secondly, a method is illustrated for the construction of p-y curves for liquefiable soils from the proposed stress-strain model. This involves scaling of stress and strain into compatible soil reaction p and pile deflection y, respectively. The scaling factors for stress and strain axis are computed following an energy-based approach, analogous to the upper-bound method used in classical plasticity theory. Finally, a series of results from centrifuge tests are presented, whereby p-y curves are back-calculated from available experimental data and qualitatively compared with that proposed by the authors

Replacing sodium bicarbonate with half amount of calcareous marine algae in the diet of beef cattle

This study evaluated the effects of feeding calcareous marine algae or sodium bicarbonate as rumen buffer on the performance, behaviour, in vitro diet digestibility, and meat quality of beef cattle. A total of 180 Charolaise bullocks (536-38 kg; 14-1 months of age) were divided into two homogeneous groups and fed a diet with a mineral mix containing 40% sodium bicarbonate or 20% calcareous marine algae (CMA) for the entire fattening period (130 days). Of the in vivo and in vitro parameters evaluated, CMA supplementation improved average daily gain and feed conversion ratio and reduced the prevalence of bloat and lameness. Bullocks fed CMA tended to exhibit a calmer behaviour while in the pen. Supplementation with CMA improved rumen pH and in vitro digestion. Meat from bullocks fed CMA showed a lower pH and higher lightness and tenderness. The results suggest that CMA is more effective than sodium bicarbonate in buffering beef cattle, with a positive impact on growth performance, feed efficiency, health, and meat quality

The transfer of fibres in the carding machine

The problem of understanding the transfer of fibres between carding-machine surfaces is addressed by considering the movement of a single fibre in an airflow. The structure of the aerodynamic flow field predicts how and when fibres migrate between the different process surfaces. In the case of a revolving-flats carding machine the theory predicts a “strong” aerodynamic mechanism between taker-in and cylinder and a “weak” mechanism between cylinder and removal cylinder resulting in effective transfer in the first case and a more limited transfer in the second