Efficacy of a novel shark bycatch mitigation device in a tuna longline fishery.

Elasmobranchs (sharks, rays, and skates) are caught throughout fisheries globally, leading to over one-third of species being threatened with extinction1. Oceanic shark populations have undergone an average 71% decline over the last half century, owing to an 18-fold increase in relative fishing pressure2. Incidental capture or 'bycatch' is a primary driver of population declines, and poses an important challenge for species conservation3. This threat necessitates mitigation strategies that exist for sharks but are often focussed on haul-back and post-capture effects for longline fishing. We trialled a novel shark bycatch mitigation device ("SharkGuard") in a commercial longline fishery targeting bluefin tuna (Thunnus thynnus), where bycatch consists largely of blue sharks (Prionace glauca) and pelagic stingrays (Pteroplatytrygon violacea).

A New Framework for Evaluating Estimates of Symbiotic Nitrogen Fixation in Forests.

Symbiotic nitrogen fixation (SNF) makes atmospheric nitrogen biologically available and regulates carbon storage in many terrestrial ecosystems. Despite its global importance, estimates of SNF rates are highly uncertain, particularly in tropical forests where rates are assumed to be high. Here we provide a framework for evaluating the uncertainty of sample-based SNF estimates and discuss its implications for quantifying SNF and thus understanding of forest function. We apply this framework to field data sets from six lowland tropical rainforests (mature and secondary) in Brazil and Costa Rica. We use this data set to estimate parameters influencing SNF estimation error, notably the root nodule abundance and variation in SNF rates among soil cores containing root nodules. We then use simulations to gauge the relationship between sampling effort and SNF estimation accuracy for a combination of parameters. Field data illuminate a highly right-skewed lognormal distribution of SNF rates among soil cores containing root nodules that were rare and spanned five orders of magnitude. Consequently, simulations demonstrated that sample sizes of hundreds to even thousands of soil cores are needed to obtain estimates of SNF that are within, for example, a factor of 2 of the actual rate with 75% probability. This represents sample sizes that are larger than most studies to date. As a result of this previously undescribed uncertainty, we suggest that current estimates of SNF in tropical forests are not sufficiently constrained to elucidate forest stand-level controls of SNF, which hinders our understanding of the impact of SNF on tropical forest ecosystem processes.

Acute presentation of a heterotopic pregnancy following spontaneous conception: a case report.

Spontaneous heterotopic pregnancy is a rare clinical condition in which intrauterine and extra uterine pregnancies occur at the same time. It can be a life threatening condition and can be easily missed with the diagnosis being overlooked. We present the case of a 40 year old patient who was treated for a heterotopic pregnancy. She had a transvaginal ultrasound because of a previous ectopic pregnancy and an intrauterine gestational sac was seen with false reassurances. The patient presented acutely with a ruptured tubal pregnancy and this was managed laparoscopically. The ectopic pregnancy was not suspected at her initial presentation. A high index of suspicion is needed in women with risk factors for an ectopic pregnancy and in low risk women who have free fluid with or without an adnexal mass with an intrauterine gestation.

Evaluating the potential effectiveness of compensatory mitigation strategies for marine bycatch.

Conservationists are continually seeking new strategies to reverse population declines and safeguard against species extinctions. Here we evaluate the potential efficacy of a recently proposed approach to offset a major anthropogenic threat to many marine vertebrates: incidental bycatch in commercial fisheries operations. This new approach, compensatory mitigation for marine bycatch (CMMB), is conceived as a way to replace or reduce mandated restrictions on fishing activities with compensatory activities (e.g., removal of introduced predators from islands) funded by levies placed on fishers. While efforts are underway to bring CMMB into policy discussions, to date there has not been a detailed evaluation of CMMB's potential as a conservation tool, and in particular, a list of necessary and sufficient criteria that CMMB must meet to be an effective conservation strategy. Here we present a list of criteria to assess CMMB that are tied to critical ecological aspects of the species targeted for conservation, the range of possible mitigation activities, and the multi-species impact of fisheries bycatch. We conclude that, overall, CMMB has little potential for benefit and a substantial potential for harm if implemented to solve most fisheries bycatch problems. In particular, CMMB is likely to be effective only when applied to short-lived and highly-fecund species (not the characteristics of most bycatch-impacted species) and to fisheries that take few non-target species, and especially few non-seabird species (not the characteristics of most fisheries). Thus, CMMB appears to have limited application and should only be implemented after rigorous appraisal on a case-specific basis; otherwise it has the potential to accelerate declines of marine species currently threatened by fisheries bycatch.

Nursing management of patients with a chest drain.

Chest drains incorporate the use of a one-way valve to drain fluid or air from the pleural cavity. The valve prevents back-flow of air and fluid into the pleural cavity. They are indicated for use when collections of fluid or air are present in the pleural space, and by draining the collection they restore efficient gaseous exchange. Little has been written on the nursing management of chest drains and the literature highlights a lack of national standardized guidelines for due to the range of thoracic conditions encountered by clinical staff. Themes such as pain management and mechanism of breathing occur frequently; however, there is a lack of up-to-date literature for the nurse to refer to. This article examines the nursing role in chest drain management from insertion to removal and includes aspects of pain management and features of a functioning chest drain.