The potential for carbon dioxide removal by enhanced rock weathering in the tropics: An evaluation of Costa Rica.

Tropical environments show great potential to sequester CO2 by enhanced rock weathering (ERW) of powdered mafic rocks applied to agricultural fields. This study seeks to assess carbon dioxide reduction (CDR) potential in the humid tropics (1) by experimental weathering of mafic rock powders in conditions simulating humid tropical soils, and (2) from weathering rates determined from a Holocene tropical soil chronosequence where parent material is andesitic sediments. Experimentally determined weathering rates by leaching of basaltic andesites from Costa Rica (Arenal and Barva) for 50 t ha-1 applications indicate potential sequestration of 2.4 to 4.5 t CO2 ha-1 yr-1, whereas the USGS basalt standard BHVO-1 yields a rate of 11.9 t ha-1 yr-1 (influenced by more mafic composition and finer particle size). The chronosequence indicates a rate of 1.7 t CO2 ha-1 yr-1. The weathering experiment consisted of 0.6 mm of powdered rock applied atop 12 mm of Ultisol at 35 °C. To simulate a tropical soil solution, 100-mL aliquots of a dilute solution of oxalic acid in carbonated DI water were rained onto soils over a 14-day period to simulate soil moisture in the humid tropics. Solutions were collected and analyzed by ICPMS for concentrations of leached cations. A potential ERW scenario for Costa Rica was assessed assuming that one-half of lowland agricultural kaolinitic soils (mainly Ultisols, common crop and pasture soils, excluding protected areas) were to receive 50 t ha-1 of annual or biennial applications of powdered mafic rock. With an experimentally determined humid tropical CDR rate for basaltic andesite (3.5 t ha-1 yr-1) and allowances for carbon costs (e.g. emissions from processing and delivery) that reduce CDR to a net 3.2 t ha-1 yr-1, potential annual CDR of this tropical nation is ∼2-4 million tons, amounting to ∼25-50 % of annual CO2 emissions (mainly from transportation in Costa Rica).

Sap flow of sweet cherry reveals distinct effects of humidity and wind under rain covered and netted protected cropping systems.

Protected cropping systems (PCS) alter the plant growing environment, though understanding of this in ventilated systems and how the new climate affects tree water uptake is limited. Sap flow sensors and weather stations were deployed in 16-year-old 'Lapins' on 'Colt' rootstock cherry trees under a ventilated Voen PCS and in an adjacent bird netted PCS. Average and maximum temperatures were consistently higher (14.7 °C and 22.9 °C) while total daily solar radiation and average wind were consistently lower (12.9 MJ/m2 and 0.2 m/s) in rain covered, in contrast to netted, PCS (13.9 °C, 21.3 °C, 13.7 MJ/m2 and 0.9 m/s). Over the season, a threefold lower daily sap flow rate was observed under rain covered PCS. Using generalised additive modelling (GAM), the influence of individual climate parameters on sap flow were predicted. Whilst sap flow was only slightly affected by relative humidity (RH) less than 60%, above this threshold sap flow rapidly declined under rain covered PCS whereas sap flow more gradually declined above 20% RH under netted PCS. Overall, our novel modelling approach led to the discovery of the 60% RH critical threshold on predicted sap flow and the indirect effect that wind speeds have on sap flow under PCS.

Delayed Symptomatic Pulmonary Embolism Secondary to Bone Cement After Percutaneous Vertebroplasty.

BACKGROUND: Percutaneous vertebroplasty (PVP) is a common procedure performed on patients suffering from osteoporotic compression fractures. Complications of the bone cement escaping both locally as well as systemically into pulmonary circulation leading to pulmonary embolism (PE) have been reported in ≤26% of patients. CASE REPORT: A 57-year-old woman presented to the emergency department with complaints of chest pain, fever, and cough. The patient had a history of an outpatient PVP from compression fractures of T5 and T7 performed 25 days before her presentation. She was in moderate respiratory distress and placed on bilateral positive airway pressure with improvement of her respiratory status. Laboratory results were remarkable for an elevated D-dimer, normal B-type natriuretic peptide, and decreased pH on venous blood gas. Pulmonary computed tomography angiography demonstrated bone cement PE in both the left lower lobe and a right middle lobe pulmonary artery. She was admitted to the hospital with improvement of her respiratory status with supportive treatment only. She was discharged after a 4-day hospital stay but died unexpectedly in her sleep 38 days after discharge. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: PVP is a common procedure that carries a risk of PE from bone cement embolization. Most of these events occur during the procedure, making the diagnosis obvious. However, delayed presentations from weeks to years have been reported. The emergency physician should consider bone cement embolization in the differential diagnosis in any patient with chest pain and shortness of breath that also has a history of PVP.

Patient and physician perceptions of lung cancer care in a multidisciplinary clinic model.

Background: Lung cancer (lc) is a complex disease requiring coordination of multiple health care professionals. A recently implemented lc multidisciplinary clinic (mdc) at Kingston Health Sciences Centre, an academic tertiary care hospital, improved timeliness of oncology assessment and treatment. This study describes patient, caregiver, and physician experiences in the mdc. Methods: We qualitatively studied patient, caregiver, and physician experiences in a traditional siloed care model and in the mdc model. We used purposive sampling to conduct semi-structured interviews with patients and caregivers who received care in one of the models and with physicians who worked in both models. Thematic design by open coding in the ATLAS.ti software application (ATLAS.ti Scientific Software Development, Berlin, Germany) was used to analyze the data. Results: Participation by 6 of 72 identified patients from the traditional model and 6 of 40 identified patients from the mdc model was obtained. Of 9 physicians who provided care in both models, 8 were interviewed (2 respirologists, 2 medical oncologists, 4 radiation oncologists). Four themes emerged: communication and collaboration, efficiency, quality of care, and effect on patient outcomes. Patients in both models had positive impressions of their care. Patients in the mdc frequently reported convenience and a positive effect of family presence at appointments. Physicians reported that the mdc improved communication and collegiality, clinic efficiency, patient outcomes and satisfaction, and consistency of information provided to patients. Physicians identified lack of clinic space as an area for mdc improvement. Conclusions: This qualitative study found that a lc mdc facilitated patient communication and physician collaboration, improved quality of care, and had a perceived positive effect on patient outcomes.

Method for Recording Broadband High Resolution Emission Spectra of Laboratory Lightning Arcs.

Lightning is one of the most common and destructive forces in nature and has long been studied using spectroscopic techniques, first with traditional camera film methods and then digital camera technology, from which several important characteristics have been derived. However, such work has always been limited due to the inherently random and non-repeatable nature of natural lightning events in the field. Recent developments in lightning test facilities now allow the reproducible generation of lightning arcs within controlled laboratory environments, providing a test bed for the development of new sensors and diagnostic techniques to understand lightning mechanisms better. One such technique is a spectroscopic system using digital camera technology capable of identifying the chemical elements with which the lightning arc interacts, with these data then being used to derive further characteristics. In this paper, the spectroscopic system is used to obtain the emission spectrum from a 100 kA peak, 100 µs duration lightning arc generated across a pair of hemispherical tungsten electrodes separated by a small air gap. To maintain a spectral resolution of less than 1 nm, several individual spectra were recorded across discrete wavelength ranges, averaged, stitched, and corrected to produce a final composite spectrum in the 450 nm (blue light) to 890 nm (near infrared light) range. Characteristic peaks within the data were then compared to an established publicly available database to identify the chemical element interactions. This method is readily applicable to a variety of other light emitting events, such as fast electrical discharges, partial discharges, and sparking in electrical equipment, apparatus, and systems.

A novel airway management strategy for cervical necrotising fasciitis secondary to Bezold's abscess.

We describe a rare case of cervical necrotising fasciitis caused by mastoiditis and Bezold's abscess. This case was complicated by a tracheostomy delaying wound healing. A novel strategy to repair the tracheotomy defect using Permacol™, an acellular porcine dermal substitute, and a local muscle flap not previously reported in the literature is described to allow the use of negative pressure wound therapy dressing. This technique may be employed in similar applications for non-healing tracheotomy wounds.

Contemporary global perspectives of medical students on research during undergraduate medical education: a systematic literature review.

BACKGROUND: The need for increased expertise in evidence-based medicine and concerns about the decreasing numbers of physician-scientists have underscored the need for promoting and encouraging research in medical education. The critical shortage of physician-scientists has assumed a dimension demanding a coordinated global response. This systematic review examined the perceptions of medical students regarding research during undergraduate medical school from a global perspective. METHODS: Articles for this review were searched using PubMed, SCOPUS and Cochrane. Studies published within the last 10 years of the start date of the study that met specified criteria were included. Identified articles were initially screened by title as well as keywords and their abstracts were further screened to determine relevance. Full-text of screened articles were read for validation prior to inclusion. RESULTS: A total of 26 articles from the literature met the set criteria for final inclusion. Contents of the abstracts and corresponding full-text articles were analyzed for themes on the research perspectives of medical students. The themes derived comprised: research interest, physician-scientist decline and shortage, responses to physician-scientist shortage, curriculum issues, skills (motivation and self-efficacy), research needs, socioeconomic and cultural issues, and barriers. CONCLUSION: Despite the wide variations in medical education systems worldwide, the perspectives of medical students on research in undergraduate medical education shared many common themes. Globally, medical students underscored the necessity and importance of research in medical education as reflected by many students reporting positive attitudes and interest in research endeavors. Moreover, a worldwide consensus emerged regarding the decline in the numbers of physician-scientists and the necessity for a reversal of that trend. Various barriers to research engagement and participation were highlighted.

Rupture of an Occult Intracranial Mycotic Aneurysm after Intravenous Thrombolysis with Recombinant Tissue Plasminogen Activator for Acute Ischemic Stroke.

BACKGROUND: The treatment of acute ischemic stroke with recombinant tissue plasminogen activator (rtPA) has become the mainstay of treatment, but its use carries a risk of subsequent intracranial hemorrhage (ICH). Guidelines have been developed to aid in the selection of the appropriate candidates to treat with rtPA to reduce this risk. We present a case of a stroke patient who was an appropriate candidate and was treated with rtPA who experienced a fatal subarachnoid hemorrhage due to a ruptured mycotic aneurysm (MA). CASE REPORT: A 51-year-old man presented to the Emergency Department with acute neurological symptoms concerning for acute ischemic stroke. His National Institutes of Health Stroke Scale score was 22. Emergent noncontrast head computed tomography (CT) revealed no sign of hemorrhage. The patient received intravenous rtPA, and about 1 h after the infusion was started, he had an acute deterioration in his mental status. Repeat CT scan revealed a large subarachnoid hemorrhage, and the patient was later found to have two intracranial aneurysms consistent with a ruptured MA that were related to his remote history of infective endocarditis. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: The majority of MAs are caused by infective endocarditis. In patients presenting with acute neurologic symptoms with a history of infective endocarditis, emergency physicians should strongly consider obtaining CT angiography to rule out MA prior to treating presumed acute ischemic stroke with rtPA.

Delayed Onset of Atrial Fibrillation and Ventricular Tachycardia after an Automobile Lightning Strike.

BACKGROUND: Lightning strike is a rare medical emergency. The primary cause of death in lightning strike victims is immediate cardiac arrest. The mortality rate from lightning exposure can be as high as 30%, with up to 70% of patients left with significant morbidity. CASE REPORT: An 86-year-old male was struck by lightning while driving his vehicle and crashed. On initial emergency medical services evaluation, he was asymptomatic with normal vital signs. During his transport, he lost consciousness several times and was found to be in atrial fibrillation with intermittent runs of ventricular tachycardia during the unconscious periods. In the emergency department, atrial fibrillation persisted and he experienced additional episodes of ventricular tachycardia. He was treated with i.v. amiodarone and admitted to cardiovascular intensive care unit, where he converted to a normal sinus rhythm on the amiodarone drip. He was discharged home without rhythm-control medications and did not have further episodes of dysrhythmias on follow-up visits. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Lightning strikes are one of the most common injuries suffered from natural phenomenon, and short-term mortality ordinarily depends on the cardiac effects. This case demonstrates that the cardiac effects can be multiple, delayed, and recurrent, which compels the emergency physician to be vigilant in the initial evaluation and ongoing observation of patients with lightning injuries.

Microanatomical diversification of the zona pellucida in aplochelioid killifishes.

This study investigates zona pellucida (ZP) ultrastructure in fertilized eggs of annual killifishes (suborder Aplocheiloidei), a group of highly specialized fishes that are able to survive desiccation for several weeks to months before they hatch. Little is known about ZP or chorionic ultrastructure sustaining these life-history modes, so scanning electron microscopy (SEM) was used to describe this trait in a large number of aplocheiloids with a focus on the family Rivulidae and the genus Hypsolebias. New images of ZP ultrastructure for 52 aplocheiloid species are provided, more than doubling the number characterized thus far. The evolution of chorionic structure within this group is studied using these new data. Characters were coded into a morphological matrix and optimized onto a consensus phylogeny to assess phylogenetic signal and reconstruct ancestral character states. Although ZP characters seem highly homoplastic and exhibit a large amount of structural convergence among lineages, aplocheiloid killifishes have evolved a number of unique structures associated with the chorion. Some annual species seem to have lost long filaments because eggs are deposited in the soil instead of being adhered to aquatic plants.

Lessons Learned From Developing an Eradication Investment Case for Lymphatic Filariasis.

In the last few years, the concepts of disease elimination and eradication have again gained consideration from the global health community, with Guinea worm disease (dracunculiasis) on track to become the first parasitic disease to be eradicated. Given the many complex and interlinking issues involved in committing to a disease eradication initiative, such commitments must be based on a solid assessment of a broad range of factors. In this chapter, we discuss the value and implications of undertaking a systematic and fact-based analysis of the overall situation prior to embarking on an elimination or eradication programme. As an example, we draw upon insights gained from a series of lymphatic filariasis (LF) studies from our research group that adopted an eradication investment case (EIC) framework. The justification for EICs, and related epidemiological, geospatial and other mathematical/operational research modelling, stems from the necessity for proper planning prior to committing to disease eradication. Across all considerations for LF eradication, including: time, treatments, level of investments necessary, health impact, cost-effectiveness, and broader economic benefits, scaling-up mass drug administration coverage to all endemic communities immediately provided the most favourable results. The coherent and consistent pursuit of eradication goals, operationally tailored to a given socioecological system and based on integrated measures of available tools will lead relatively rapidly to elimination in many parts of endemic areas and provide the cornerstone towards eradication.

The Pan-University Network for Global Health: framework for collaboration and review of global health needs.

In the current United Nations efforts to plan for post 2015-Millennium Development Goals, global partnership to address non-communicable diseases (NCDs) has become a critical goal to effectively respond to the complex global challenges of which inequity in health remains a persistent challenge. Building capacity in terms of well-equipped local researchers and service providers is a key to bridging the inequity in global health. Launched by Penn State University in 2014, the Pan University Network for Global Health responds to this need by bridging researchers at more than 10 universities across the globe. In this paper we outline our framework for international and interdisciplinary collaboration, as well the rationale for our research areas, including a review of these two themes. After its initial meeting, the network has established two central thematic priorities: 1) urbanization and health and 2) the intersection of infectious diseases and NCDs. The urban population in the global south will nearly double in 25 years (approx. 2 billion today to over 3.5 billion by 2040). Urban population growth will have a direct impact on global health, and this growth will be burdened with uneven development and the persistence of urban spatial inequality, including health disparities. The NCD burden, which includes conditions such as hypertension, stroke, and diabetes, is outstripping infectious disease in countries in the global south that are considered to be disproportionately burdened by infectious diseases. Addressing these two priorities demands an interdisciplinary and multi-institutional model to stimulate innovation and synergy that will influence the overall framing of research questions as well as the integration and coordination of research.

Clinical heterogeneity of the C9orf72 genetic mutation in frontotemporal dementia.

The C9orf72 genetic mutation represents the most common cause of familial frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). Studies over the last 2 years have revealed a number of key features of this mutation in the fields of clinical neurology, imaging, pathology, and genetics. Despite these efforts, the clinical phenotype appears to extend beyond FTD and ALS into the realm of psychiatric disease, and while highly variable survival rates have been reported, the clinical course of carriers remains relatively unexplored. This report describes two contrasting C9orf72 cases, one with a protracted indolent course dominated by neuropsychiatric features and the other with a rapidly progressive dementia. In both cases, initial structural brain imaging was relatively normal.

A low-cost mesocosm for the study of behaviour and reproductive potential in Afrotropical mosquito (Diptera: Culicidae) vectors of malaria.

A large-scale mesocosm was constructed and tested for its effectiveness for use in experiments on behaviour, reproduction and adult survivorship in the Afrotropical malaria vector Anopheles gambiae s.s. Giles (Diptera: Culicidae) in temperate climates. The large space (82.69 m(3) ) allowed for semi-natural experiments that increased demand on a mosquito's energetic reserves in an environment of widely distributed resources. A one-piece prefabricated enclosure, made with white netting and vinyl, prevented the ingress of predators and the egress of mosquitoes. Daylight and white materials prompted the mosquitoes to seclude themselves in restricted daytime resting sites and allowed the easy collection of dead bodies so that daily mortality could be assessed accurately using a method that accounts for the loss of a proportion of bodies. Here, daily, age-dependent mortality rates of males and females were estimated using Bayesian Markov chain Monte Carlo simulation. In overnight experiments, mosquitoes successfully located plants and took sugar meals. A 3-week survival trial with a single cohort demonstrated successful mating, blood feeding, oviposition and long life. The relatively low cost of the mesocosm and the performance of the mosquitoes in it make it a viable option for any behavioural or ecological study of tropical mosquitoes in which space and seasonal cold are constraining factors.

First Report of Phakopsora pachyrhizi on Soybean in Costa Rica.

Phakopsora meibomiae (Arthur) Arthur has been reported to occur in several legume species in the tropical regions of Central and South America. In Costa Rica, this pathogen was initially reported as P. pachyrhizi Sydow (1); however, to our knowledge, P. pachyrhizi has not been detected in Costa Rica. In routine evaluations of a 0.2-ha field planted with soybean (Glycine max (L.) Merr var. CIGRAS 06) in La Garita, Alajuela, Costa Rica, symptoms similar to Asian soybean rust were observed in December 2012 and January 2013. Soybean plants were at growth stages R4 to R5 when these symptoms were observed, which included yellow spots on leaves with brown spots on the abaxial surface. Further evaluations at growth stage R5 to R6 indicated that the spots had coalesced, turned grayish-brown, and caused substantial defoliation. Microscopic examination of symptomatic leaves showed the presence of uredinia and urediniospores on the lower surface of the leaf. While initial symptoms were on the southern side of the field, a substantial area of the field was infected at the second evaluation. Infected leaves were submitted to the USDA-ARS Foreign Disease-Weed Science Research Unit under the appropriate USDA-Animal Plant Health Inspection Service permit for molecular characterization and identification. Urediniospores were collected by washing infected leaves with sterile water and then pelleted by centrifugation. DNA was extracted from urediniospore pellets and excised leaf pieces using a DNeasy Plant Mini Kit (Qiagen, Germantown, MD), and eight samples were amplified in real-time polymerase chain reaction (PCR) with P. pachyrhizi-specific primers Ppm1 and Ppa2 but not with the P. meibomiae-specific primers Ppm1 and Pme2 (2). Nucleotide sequence alignment of the internal transcribed spacer (ITS) regions 1 and 2 that were amplified by PCR using the primers Ppa1 and Ppa2 further confirmed the identification as P. pachyrhizi. To the best of our knowledge, this is the first known confirmation of soybean rust, caused by P. pachyrhizi in Costa Rica. CIGRAS-06 is the only soybean variety bred in the country as well as one of the very few varieties available for growers. Given that breeding for disease resistance is not a short-term option for P. pachyrhizi, alternative disease management strategies will have to be developed. References: (1) K. R. Bromfield. Soybean Rust, Monograph No. 11. APS Press, St. Paul, MN, 1984. (2) R. D. Frederick et al. Phytopathology 92:217, 2002.

Determinants of male Aedes aegypti and Aedes polynesiensis (Diptera: Culicidae) response to sound: efficacy and considerations for use of sound traps in the field.

Understanding the mating competitiveness of male mosquitoes in field settings is essential to programs relying on the mass release of modified male mosquitoes, yet studies on male ecology have been hampered by the lack of a convenient trapping method. An existing promising method makes use of the innate attraction of males to female flight tones. Here, we present laboratory, greenhouse, and field experiments on the efficacy of sound traps for the collection of Aedes aegypti (L.) and Aedes polynesiensis Marks, and laboratory experiments with Ae. aegypti on the effects of male age, size, and mating status on responsiveness to a range of frequencies. Age and mating status influenced the overall responsiveness to sound, whereas male size did not. There were no interactions between these factors and sound frequency. A Centers for Disease Control and Prevention miniature light trap modified to produce a tone of 465 Hz collected 76.2% of Ae. aegypti males in laboratory cages, and 49.7% of males in a greenhouse enclosure. In two sets of experiments in laboratory cages, 50.8 and 46.5% of male Ae. polynesiensis were captured with a trap producing a tone of 440 Hz. In the field, CDC miniature light traps or BG-Sentinel traps fitted with a portable speaker producing tones of 440 or 465 Hz captured significantly more male Ae. polynesiensis when placed near a male swarm than did traps that did not produce sound. When the trap was placed at a distance of 16.5 m from the nearest swarm, there was no significant difference in the number of males caught between control and sound-producing traps. The numbers of Ae. aegypti males captured were low under all circumstances in the field.

Swarming behavior of Aedes polynesiensis (Diptera: Culicidae) and characterization of swarm markers in American Samoa.

We characterize the swarming behavior of male Aedes polynesiensis (Marks) in American Samoa. Instead of swarming around a blood host, males used the base of certain trees as a marker. Repeated sampling proved nondestructive and allowed us to investigate the impact of static (e.g., tree species) and dynamic (e.g., barometric pressure) characters on the likelihood of swarm presence and intensity. Tree circumference and oviposition activity (number of Ae. polynesiensis reared from oviposition cups) were significant positive predictors of the number of males in a swarm. Tree circumference and diameter were significantly positively associated, and canopy height was significantly negatively associated, with swarm occurrence. Comparisons between males swarming early and late during the swarming period allowed for insight into swarm composition in terms of male size and the amount of putative fluid (e.g., nectar) in the crop, indicators of energetic reserves. Males collected during the late period had significantly larger wings and less crop contents than did males of the early cohort. Because the ecology of male Ae. polynesiensis remains understudied, we consider how the current results could facilitate further studies related to applied autocidal strategies as well as the evolution of host-based mating behavior.