Hypolimnetic oxygen injection is a management tool used to improve water quality by preventing anoxia and associated phosphorus release from the sediments. An additional benefit would be formation of a low‐oxygen refuge for large‐bodied herbivorous zooplankton in the metalimnion. The magnitude and timing of hypolimnetic oxygenation was deliberately manipulated during summer 1997 in Irondequoit Bay, a eutrophic Lake Ontario embayment (New York, USA), to maintain metalimnetic dissolved oxygen (DO) concentrations in the range of 1–2 mg/L. We assessed the vertical distributions of fish and zooplankton in 1997, a year with controlled oxygenation, and 1996, a year with oxygenation but without a deliberate attempt to create amenable refuge conditions. After initiation of oxygenation, June through early August metalimnetic DO in 1997 was 1.8 ± 0.5 mg/L (means ± 2 se), whereas metalimnetic DO in 1996 was 3.8 ± 1.0 mg/L. Hydroacoustic surveys in 1997 and gillnet catches in both years indicated that >96% of planktivorous fish, alewives (Alosa pseudoharengus) and emerald shiners (Notropis atherinoides), were restricted to depths with DO > 4.0 mg/L. A refuge effect in 1996 was slight and evidenced only by significantly larger zooplankton in the metalimnion while densities of Daphnia galeata medotae and D. retrocurva were similar or significantly greater in the epilimnion. In 1997, the refuge effect was strong despite an almost twofold increase in planktivorous fish abundance compared to 1996. Overall zooplankton densities were similar in the epilimnion and metalimnion while zooplankton size and densities of both daphnids were significantly greater in the metalimnion. Densities of an invertebrate predator, Mesocyclops edax, were also significantly higher in the metalimnion compared to the epilimnion. Despite high fish abundance in 1997, mean summer (late May through August) chlorophyll a decreased 29% compared to 1996, consistent with expectations from grazing by large Daphnia protected in the refuge. Presence of large‐bodied zooplankton in 1997 despite high planktivore abundance demonstrated that successful creation of a low‐oxygen refuge from fish predation was possible in an open Great Lakes embayment where traditional biomanipulation via fish removal was not practical.

In the δAsn20 Drosophila stock, the N-linked glycosylation site of opsin in Rl-6 receptors (Rhl) is absent. We used electroretinography (ERG), microspectrophotometry (MSP), and electron microscopy (EM) to quantify visual cell defects. Positive controls, w9, had wild type Rhl. MSP revealed minimal photopigment in δAsn20 for 6 days posteclosion; w9 had near normal visual pigment. ERG sensitivity and prolonged depolarizing afterpotential (PDA) were compared for δAsn20 and w9. δAsn20's Rl-6 function is decreased 100–fold at eclosion and diminishes until only R7/8 functions at 11 days. What little rhodopsin is routed to the rhabdomere functions. Morphometry showed smaller Rl-6 rhabdomeres in δAsn20 for 8 days posteclosion. Rhabdomeres in w9 were normal. A negative control, ninaE0117, a deletion of the Rhl gene, also has small rhabdomeres. δAsn20 and ninaE0117 lack the extreme rhabdomere elimination of ora (outer rhabdomeres absent), a nonsense mutant interrupting Rhl's coding sequence. δAsn20 and ora have surplus membrane while ninaE0117 does not. Freeze fracture reveals that δAsn20's rhabdomeric P-face particle count is as low as for vitamin A deprivation, consistent with an opsin defect. High particle density, organized into rows, is present in adjacent plasmalemma where surplus membrane accumulates. In summary, δAsn20 interferes with either synthesis, deployment, or maintenance of opsin.

No abstract

The Critically Endangered Chapman's pygmy chameleon Rhampholeon chapmanorum is endemic to the low elevation rainforest of the Malawi Hills in southern Malawi. Much of this forest has been converted to agriculture and it was uncertain whether chameleon populations have persisted. We used current and historical satellite imagery to identify remaining forest patches and assess deforestation. We then surveyed forest patches for the presence of this chameleon, and assessed its genetic diversity and structure. We estimated that 80% of the forest has been destroyed since 1984, although we found extant populations of the chameleon in each of the patches surveyed. Differentiation of genetic structure was strong between populations, suggesting that gene flow has been impaired. Genetic diversity was not low, but this could be the result of a temporal lag as well as lack of sensitivity in the mitochondrial marker used. Overall, the impact of forest loss is assumed to have led to a large demographic decline, with forest fragmentation preventing gene flow.

In this work, we describe the digital imaging network (DIN), picture archival and communication system (PACS), and radiology information system (RIS) currently being implemented at the Clinical Center, National Institutes of Health (NIH). These systems are presently in clinical operation. The DIN is a redundant meshed network designed to address gigabit density and expected high bandwidth requirements for image transfer and server aggregation. The PACS projected workload is 5. IN THIS WORK, we describe the digital imaging network (DIN), picture archival and communication system (PACS), and radiology information system (RIS) currently being deployed at the Clinical Center, National Institutes of Health (NIH). The first phase of the NIH Clinical Center DINIPACSIRIS solution was implemented within a to-month period and followed a master plan that started with the issuance of a PACS Request for Proposal (RFP).l During this initial phase, all systems were brought into "live state," ie, into clinical operation.Historically, the deployment of a modern RIS and implementation of a fast DIN at the NIH Clinical Center were driven by needs created by a PACS environment. In fact, we consider a RIS and a properly sized DIN mandatory prerequisites for an enterprise-wide PACS. The RIS, in turn, has its own prerequisites that are related to the existence of a bidirectional messaging mechanism with the hospital information system (HIS), preferably using electronic data sharing standards such as Health Level 7 (HL-7),2 Once the RISIHIS and associated interfaces are in place, as well as a network capable of handling imaging density, then one is ready to start a successful deployment of an enterprise-wide PACS. This statement does not imply that the physical implementation of these systems should happen in a serial fashion. Actually, in our case, all of these systems were implemented in parallel, yielding greater economies of scale and resource optimization. RADIOLOGY INFORMATION SYSTEMThe RIS follows a client-server model and provides tools to order examinations, schedule resources, retrieve and review results (including images, as an option), chart clinical data, and generate management reports. The RIS also offers interesting possibilities related to increased research support. The benefits yielded by a well-design, welldeployed RIS are associated with enhancements in the quality of radiologic services, improvements in data access, potential cost reductions, and improvements in operational processes. Ultimately, the goal of our DINIPACSIRIS project is to improve workflow within the enterprise.In order to allow interoperability across the enterprise, the RIS must be integrated or, at least, interfaced to other medical information systems and mission-critical legacy systems. Our RIS interfaces include a PACSIRIS broker engine, a bidirectional interface to the digital dictation system, and several bidirectional interfaces to the HIS including incoming/outgoing admissions, discharges, and transfers (ATDs/demographics), orders (with ...