Expected limits on the ocean acidification buffering potential of a temperate seagrass meadow.

Ocean acidification threatens many marine organisms, especially marine calcifiers. The only global-scale solution to ocean acidification remains rapid reduction in CO2 emissions. Nevertheless, interest in localized mitigation strategies has grown rapidly because of the recognized threat ocean acidification imposes on natural communities, including ones important to humans. Protection of seagrass meadows has been considered as a possible approach for localized mitigation of ocean acidification due to their large standing stocks of organic carbon and high productivity. Yet much work remains to constrain the magnitudes and timescales of potential buffering effects from seagrasses. We developed a biogeochemical box model to better understand the potential for a temperate seagrass meadow to locally mitigate the effects of ocean acidification. Then we parameterized the model using data from Tomales Bay, an inlet on the coast of California, USA which supports a major oyster farming industry. We conducted a series of month-long model simulations to characterize processes that occur during summer and winter. We found that average pH in the seagrass meadows was typically within 0.04 units of the pH of the primary source waters into the meadow, although we did find occasional periods (hours) when seagrass metabolism may modify the pH by up to ±0.2 units. Tidal phasing relative to the diel cycle modulates localized pH buffering within the seagrass meadow such that maximum buffering occurs during periods of the year with midday low tides. Our model results suggest that seagrass metabolism in Tomales Bay would not provide long-term ocean acidification mitigation. However, we emphasize that our model results may not hold in meadows where assumptions about depth-averaged net production and seawater residence time within the seagrass meadow differ from our model assumptions. Our modeling approach provides a framework that is easily adaptable to other seagrass meadows in order to evaluate the extent of their individual buffering capacities. Regardless of their ability to buffer ocean acidification, seagrass meadows maintain many critically important ecosystem goods and services that will be increasingly important as humans increasingly affect coastal ecosystems.

Congenital Vallecular Cyst as a Cause of Neonatal Stridor and Apnea.

An infant who presents with stridor and apnea constitutes a challenge for emergency physicians in terms of diagnosis and management. Among the rarest of causes for these symptoms, congenital vallecular cysts can cause devastating outcomes if left undiagnosed. Reported here is a case of intermittent episodes of stridor and apnea in a 4-day-old neonate with a previously undiagnosed vallecular cyst. The process by which the infant was stabilized, correctly diagnosed, and successfully treated for a life-threatening airway obstruction is explained. After a discussion of vallecular cysts, methods for preparing for and executing proper airway management in an infant who presents with apnea and stridor are considered.

Ataxia and Headache in a Child: A Case of Acute Cerebellar Infarction.

A 4-year-old female patient presents to the pediatric emergency department with acute onset of ataxia and occipital headache. Initial investigation, including computed tomography imaging, failed to demonstrate any focal neurologic lesion. Subsequent studies, however, reveal an acute thrombosis of the superior cerebellar artery. Further work up identified the likely causative factor to be a heterozygous mutation at the methylene tetrahydrofolate reductase gene. In this case report, we will discuss the work-up of pediatric ataxia, the evaluation and management of cerebrovascular accidents in children, and the association between stroke and mutation of the methylene tetrahydrofolate reductase gene.

Acute Genitourinary Swelling and Erythema as Presenting Symptoms of Henoch-Schonlein Purpura.

Henoch-Schonlein purpura (HSP) may present in a variety of ways, most commonly with joint pain or the distinctive palpable purpura. Genitourinary manifestations of HSP are less common and may precede the classic signs and symptoms of HSP, making the diagnosis difficult. We report a case of a 19-month-old boy with penile and scrotal erythema and swelling at presentation who was later diagnosed with HSP.

A case of penetrating neck trauma in a child.

Penetrating injuries to the neck are potentially devastating, and recommendations concerning their evaluation have generated extensive discussion over the years. In this article, we present the case of a 9-year-old girl who narrowly missed a serious vascular injury when she fell on a pencil. We also discuss the most current recommendations concerning management of zone II injuries to the neck of a pediatric patient.

Effectiveness of a medicolegal lecture on risk-reduction medical record documentation by pediatric residents.

OBJECTIVE: To determine the effectiveness of a medicolegal lecture on risk-reduction documentation by residents in a pediatric emergency department. DESIGN/METHODS: Pediatric residents at an academic children's hospital were offered a 1-hour lecture on reducing medicolegal risks. Residents in attendance made up the intervention group (IG) and nonattendants were the control group (CG). The primary outcome was risk-reduction documentation (RRD) using patients with chief complaints of abdominal pain, extremity fractures, and lacerations with potential foreign body. RESULTS: For abdominal pain patients, RRD by IG improved 6.1% compared with 15.1% for the CG. For fracture patients, RRD by IG improved 20% compared with 26.5% decrease by CG. For laceration patients, RRD by IG decreased 20.8% compared with 30.6% decrease by CG. Although none reached statistical significance, the postintervention IG rates were greater. CONCLUSIONS: We showed a trend toward improvement in the rate of risk-reduction medical record documentation.