Eddy-resolving simulation of plankton ecosystem dynamics in the California Current System

Author Posting. © Elsevier B.V., 2006. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Deep Sea Research Part I: Oceanographic Research Papers 53 (2006): 1483-1516, doi:10.1016/j.dsr.2006.06.005.We study the dynamics of the planktonic ecosystem in the coastal upwelling zone within the California Current System using a three-dimensional, eddy-resolving circulation model coupled to an ecosystem/biogeochemistry model. The physical model is based on the Regional Oceanic Modeling System (ROMS), configured at a resolution of 15 km for a domain covering the entire U.S. West Coast, with an embedded child grid covering the central California upwelling region at a resolution of 5 km. The model is forced with monthly mean boundary conditions at the open lateral boundaries as well as at the surface. The ecological/biogeochemical model is nitrogen based, includes single classes for phytoplankton and zooplankton, and considers two detrital pools with different sinking speeds. The model also explicitly simulates a variable chlorophyll-to-carbon ratio. Comparisons of model results with either remote sensing observations (AVHRR, SeaWiFS) or in situ measurements from the CalCOFI program indicate that our model is capable of replicating many of the large-scale, time averaged features of the coastal upwelling system. An exception is the underestimation of the chlorophyll levels in the northern part of the domain, perhaps because of the lack of short-term variations in the forcing from the atmosphere. Another shortcoming is that the modeled thermocline is too diffuse, and that the upward slope of the isolines toward the coast is too small. Detailed time-series comparisons with observations from Monterey Bay reveal similar agreements and discrepancies. We attribute the good agreement between the modeled and observed ecological properties in large part to the accuracy of the physical fields. In turn, many of the discrepancies can be traced back to our use of monthly mean forcing. Analysis of the ecosystem structure and dynamics reveal that the magnitude and pattern of phytoplankton biomass in the nearshore region are determined largely by the balance of growth and zooplankton grazing, while in the offshore region, growth is balanced by mortality. The latter appears to be inconsistent with in situ observations and is a result of our consideration of only one zooplankton size class (mesozooplankton), neglecting the importance of microzooplankton grazing in the offshore region. A comparison of the allocation of nitrogen into the different pools of the ecosystem in the 3-D results with those obtained from a box model configuration of the same ecosystem model reveals that only a few components of the ecosystem reach a local steady-state, i.e. where biological sources and sinks balance each other. The balances for the majority of the components are achieved by local biological source and sink terms balancing the net physical divergence, confirming the importance of the 3-D nature of circulation and mixing in a coastal upwelling system.Most of this work has been made possible by two grants from NASA. Additional support is acknowledged from NSF’s ITR program

A Treatable Cause of Visual Loss in Fibrous Dysplasia

Fibrous dysplasia is a rare cause of compressive optic neuropathy. We report a case of acute cystic degeneration of the sphenoid sinus due to fibrous dysplasia causing optic nerve compression. This finding was unexpected and not apparent on CT scanning

Malingering and Secondary Gain in the Afghanistan and Iraq Conflicts (.pdf)

Functional or non-organic visual loss (NOVL) is defined as a loss or decrease in visual acuity or visual field range with no identifiable organic cause. NOVL can be a difficult diagnosis to make and requires a high index of suspicion. This can be especially difficult in the setting of true organic pathology, as was the experience with several patients presenting to an Ophthalmology clinic after sustaining either ocular or non-ocular injuries. This case series examines several such patients with NOVL that were either injured or developed an ocular condition while serving in Iraq or Afghanistan. The aim of this series is to provide a review of several possible presentations of NOVL and the various modalities that the ophthalmologist can use to arrive at a diagnosis of NOVL

Visual and anatomic outcomes of vitrectomy with temporary keratoprosthesis or endoscopy in ocular trauma with opaque cornea

■ BACKGROUND AND OBJECTIVE: To examine the outcomes of vitrectomy in ocular trauma with opaque cornea. ■ PATIENTS AND METHODS: This retrospective study included 17 eyes of 16 patients who underwent vitrectomy with temporary keratoprosthesis or endoscopy at Walter Reed Army Medical Center, Washington, DC, from March 2003 to October 2010. ■ RESULTS: A temporary keratoprosthesis was used in 8 eyes (47%) and endoscopy in 9 eyes (53%). Overall, the number of eyes with visual acuity of 20/200 or better improved from 0 at baseline to 5 (29%) at 6 months. The number of eyes with retinal detachment also improved from 10 (59%) at baseline to 3 (18%) at 6 months. ■ CONCLUSION: Vitrectomy may be safely performed in ocular trauma with opaque cornea using a temporary keratoprosthesis or endoscopy with comparable outcomes. Endoscopy allows earlier diagnosis and treatment of occult pathology and requires less time and fewer procedures to implement than the temporary keratoprosthesis. Copyright © SLACK Incorporated

Treatment of Inflammatory Macular Edema with Humanized Anti-CD11a Antibody Therapy

Anti-CD11a therapy, shown in animals to decrease the expression of endotoxin-induced uveitis, was successful in improving visual acuity, reducing macular thickness, and increasing the CD56bright population in uveitis patients with macular edema

Ocular tuberculosis: A clinicopathologic and molecular study

Objective: To analyze the clinical profiles, histopathologic features, and Mycobacterium tuberculosis polymerase chain reaction testing in patients with ocular tuberculosis. Design: Retrospective case series. Participants: Forty-two patients. Methods: This retrospective study was approved by the Armed Forces Institute of Pathology (AFIP) Institutional Review Board. The AFIP data banks were screened for cases with diagnosis of ocular tuberculosis using key words such as mycobacterium; tuberculosis; and acid-fast bacilli. Files and slides stained with hematoxylin-eosin and acid-fast staining were reviewed by the Division of Ocular Pathology and by the Infectious Diseases and Parasitic Diseases Pathology Branches. When available; blocks and unstained slides were sent to the Doheny Eye Institute; Los Angeles; California; for quantitative polymerase chain reaction (qPCR) analysis to detect Mycobacterium tuberculosis-specific DNA. Main Outcome Measures: Tuberculin skin test (TST) results, as well as the chest radiograph results, were recorded. When acid-fast bacilli were identified in tissue, their locations - ocular or extraocular sites - were recorded. Emphasis was placed on lymph node involvement and any systemic diseases. Results: In the histopathologic specimens, microscopy revealed a paucity of organisms, and often there were only 1 or 2 organisms associated with or near a giant cell or near an area of necrosis. The qPCR analysis was performed on 6 biopsy specimens. These specimens showed necrotizing granulomatous inflammation from 6 different patients; 3 had positive qPCR results. In 2 of the 3 cases with positive qPCR results, acid-fast bacilli were not found in the tissue sections. In 17 patients, TST results were available; 10 had positive results (60%) and 7 had negative results (40%). Fourteen chest radiograph results were submitted, and 8 (57%) of 14 patients had normal chest films. Conclusions: This study suggests that in dealing with those populations at increased risk of tuberculosis (e.g., immigrants from endemic areas and human immunodeficiency virus-infected patients) or patients receiving biologic therapy, the ophthalmologist should endeavor to entertain this diagnosis and to rely on the support of infectious disease specialists and pulmonologists to help solidify the diagnosis, because the current methods for the diagnosis have limited sensitivity. Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article. © 2011 American Academy of Ophthalmology

Long-term graft survival in patients with Down syndrome after penetrating keratoplasty

PURPOSE: To determine graft survival and long-term visual outcome after penetrating keratoplasty (PK) for keratoconus in patients with Down syndrome. METHODS: The records of all patients with Down syndrome who received PK by the same provider were reviewed. A retrospective analysis was performed to determine long-term graft survival, incidence of graft failure, and complication rate. RESULTS: Twenty-one PKs were performed on 18 eyes of 13 patients with Down syndrome with keratoconus. Three repeat PKs were performed for secondary graft failure. All 18 eyes had clear grafts at the most recent examination. Follow-up ranged from 4 to 88 months, with a mean of 34.9 months. The average age of patients was 42 years, with a range of 20 to 63 years. Preoperative visual acuity ranged from 20/160 to count fingers. Postoperatively, visual acuity was objectively measurable in 12 eyes of 8 patients and ranged from 20/30 to 20/200, with a mean of 20/60. Broken sutures and difficulties with unsedated suture removal complicated postoperative care in some patients. CONCLUSION: Clear grafts and improvements in visual acuity can be obtained after PK in patients with Down syndrome, but consideration must be given to careful postoperative care by health care providers and home support personnel. © 2006 Lippincott Williams & Wilkins, Inc