3,032 research outputs found
Toward identification of larval sailfish (Istiophorus platypterus), white marlin (Tetrapturus albidus), and blue marlin (Makaira nigricans) in the western North Atlantic Ocean*
The identification of larval istiophorid billfishes from the western North Atlantic Ocean has long been problematic. In the present study, a molecular technique was used to positively identify 27 larval white marlin (Tetrapturus albidus), 96 larval blue marlin (Makaira nigricans), and 591
larval sailfish (Istiophorus platypterus) from the Straits of Florida and the Bahamas. Nine morphometric measurements were taken for a subset of larvae (species known), and lower
jaw pigment patterns were recorded on a grid. Canonical variates analysis (CVA) was used to reveal the extent
to which the combination of morphometric, pigment pattern, and month of capture information was diagnostic to species level. Linear regression revealed species-specific relationships between the ratio of snout length to eye orbit diameter and standard length (SL). Confidence limits about these relationships served as defining characters for sailfish >10 mm SL and for blue and white marlin >17 mm SL.
Pigment pattern analysis indicated that 40% of the preflexion blue marlin examined possessed a characteristic
lower jaw pigment pattern and that 62% of sailfish larvae were identifiable by lower jaw pigments alone. An identification key was constructed based on pigment patterns, month of capture, and relationships between SL and the ratio of snout length to eye orbit diameter. The key yielded identifications for 69.4% of 304 (blind
sample) larvae used to test it; only one of these identifications was incorrect. Of the 93 larvae that could not be identified by the key, 71 (76.3%) were correctly identified with CVA. Although identif ication of certain
larval specimens may always require molecular techniques, it is encouraging that the majority (92.4%) of istiophorid larvae examined were ultimately identifiable from external
characteristics alone
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Neoplasia in Three Aye-Ayes (Daubentonia madagascariensis)
Tumours diagnosed in three aged captive aye-ayes (Daubentonia madagascariensis), held in two different institutions, are described. A cerebral glioblastoma was diagnosed based on histological and immunohistochemical findings in one of the animals following initial presentation with bilateral mydriasis, absent pupillary reflex, head tilt and ataxia. A second animal was humanely destroyed due to impaired locomotion associated with spondylosis and a post-mortem diagnosis of cholangiocarcinoma was made based on histology with further confirmation with immunohistochemical labelling for cytokeratin 7. A third aye-aye suffering from dental disease was diagnosed with an oral squamous cell carcinoma following an excisional biopsy from a non-healing wound in the lip. Due to progression of the neoplasia the animal was humanely destroyed and post-mortem examination revealed the presence on an additional unilateral phaeochromocytoma
Advancing MEMS Technology Usage through the MUMPS (Multi-User MEMS Processes) Program
In order to help provide access to advanced micro-electro-mechanical systems (MEMS) technologies and lower the barriers for both industry and academia, the Microelectronic Center of North Carolina (MCNC) and ARPA have developed a program which provides users with access to both MEMS processes and advanced electronic integration techniques. The four distinct aspects of this program, the multi-user MEMS processes (MUMP's), the consolidated micro-mechanical element library, smart MEMS, and the MEMS technology network are described in this paper. MUMP's is an ARPA-supported program created to provide inexpensive access to MEMS technology in a multi-user environment. It is both a proof-of-concept and educational tool that aids in the development of MEMS in the domestic community. MUMP's technologies currently include a 3-layer poly-silicon surface micromachining process and LIGA (lithography, electroforming, and injection molding) processes that provide reasonable design flexibility within set guidelines. The consolidated micromechanical element library (CaMEL) is a library of active and passive MEMS structures that can be downloaded by the MEMS community via the internet. Smart MEMS is the development of advanced electronics integration techniques for MEMS through the application of flip chip technology. The MEMS technology network (TechNet) is a menu of standard substrates and MEMS fabrication processes that can be purchased and combined to create unique process flows. TechNet provides the MEMS community greater flexibility and enhanced technology accessibility
Population connectivity in marine systems : an overview
Author Posting. © Oceanography Society, 2007. This article is posted here by permission of Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 20, 3 (2007): 14-21.There is growing consensus that life within the world’s ocean is under considerable
and increasing stress from human activities (Hutchings, 2000; Jackson et al.,
2001). This unprecedented strain on both the structure and function of marine ecosystems has
led to calls for new management approaches to counter anthropogenic impacts in the coastal ocean
(Botsford et al., 1997; Browman and Stergiou, 2004: Pikitch et al., 2004). Spatial management, including
Marine Protected Areas (MPAs), has been touted as a method for both conserving biodiversity
and managing fisheries (Agardy, 1997). Continuing debates on the efficacy of MPAs have identified
the need for models that capture the spatial dynamics of marine populations, especially with respect
to larval dispersal (Willis et al., 2003; Sale et al., 2005). Theoretical studies suggest that population connectivity plays a fundamental role in local and metapopulation dynamics, community dynamics and
structure, genetic diversity, and the resiliency of populations to human exploitation (Hastings and
Harrison, 1994; Botsford et al., 2001). Modeling efforts have been hindered, however, by the paucity of
empirical estimates of, and knowledge of the processes controlling, population connectivity in ocean
ecosystems. While progress has been made with older life stages, the larval-dispersal component of
connectivity remains unresolved for most marine populations. This lack of knowledge represents a
fundamental obstacle to obtaining a comprehensive understanding of the population dynamics of
marine organisms. Furthermore, a lack of spatial context that such information would provide has
limited the ability of ecologists to evaluate the design and potential benefits of novel conservation and
resource-management strategies.Over the years, we have each
received support from a variety of agencies
in support of research relevant to
Population Connectivity; in addition to
NSF, we acknowledge funding from the
World Bank/GEF Coral Reef Targeted
Research Program, University of Miami’s
Maytag Chair in Ichthyology, the Oak
Foundation, and the Woods Hole
Oceanographic Institutio
Pasture Conditions at the Initiation of Grazing to Optimize Forage Productivity: A Progress Report
To determine environmental, soil, and sward effects at the initiation of cattle grazing in the spring on seasonal (forage accumulated during the grazing season) and cumulative (seasonal + initial forage mass) forage accumulation (FA), 15 commercial cow-calf producers from southern Iowa were selected by historical initial grazing date. At grazing initiation, twelve .25-m2 samples were hand-clipped from each pasture and sward heights (SH) measured with a falling plane meter (4.8 kg/m2) to determine initial forage mass. At each location, soil temperature and load bearing capacity (LBC) were measured and a soil sample was collected to measure pH and moisture, P, and K concentrations. Cumulative degree-days (base=3.85°C) and precipitation at grazing initiation were calculated from NOAA records. At the beginning of each month, at least three grazing exclosures were placed on each grazed pasture to determine monthly FA. SH in each exclosure was recorded, and a .25-m2 forage sample was hand-clipped proximate to each exclosure. At the end of each month, SH was recorded and .25-m2 hand-clipped forage samples from inside exclosures were obtained. In linear regressions, cumulative and seasonal SH increased with greater soil P (r2=.5049 and .5417), soil K (r2=.4675 and .4397), and initial forage mass (r2=.1984 and .2801). Seasonal SH increased with earlier initial grazing dates (r2=.1996) and less accumulated degree-days (r2=.2364). Cumulative and seasonal FA increased with earlier initial grazing dates (r2=.2106 and .3744), lower soil temperatures (r2=.2617 and.2874), and greater soil P (r2=.3489 and .2598). Cumulative FA increased with greater soil K (r2=.4675). In quadratic regressions, cumulative and seasonal SH were correlated to soil P (r2=.6310 and .5310) and soil K (r2=.5095 and.4401). Cumulative and seasonal FA were correlated to degree days (r2=.3630 and.4013) and initial grazing date (r2=.3425 and .4088). Cumulative FA was correlated to soil P (r2=.3539), and seasonal FA was correlated to soil moisture (r2=.3688)
Applications of Hilbert Module Approach to Multivariable Operator Theory
A commuting -tuple of bounded linear operators on a
Hilbert space \clh associate a Hilbert module over
in the following sense: where and
. A companion survey provides an introduction to the theory
of Hilbert modules and some (Hilbert) module point of view to multivariable
operator theory. The purpose of this survey is to emphasize algebraic and
geometric aspects of Hilbert module approach to operator theory and to survey
several applications of the theory of Hilbert modules in multivariable operator
theory. The topics which are studied include: generalized canonical models and
Cowen-Douglas class, dilations and factorization of reproducing kernel Hilbert
spaces, a class of simple submodules and quotient modules of the Hardy modules
over polydisc, commutant lifting theorem, similarity and free Hilbert modules,
left invertible multipliers, inner resolutions, essentially normal Hilbert
modules, localizations of free resolutions and rigidity phenomenon.
This article is a companion paper to "An Introduction to Hilbert Module
Approach to Multivariable Operator Theory".Comment: 46 pages. This is a companion paper to arXiv:1308.6103. To appear in
Handbook of Operator Theory, Springe
The Influence of a Ubiquitous Filter Feeder on Coastal Microbial Communities.
Doliolids have a unique ability to impact the marine microbial community through bloom events and high filtration rates. Their predation on large eukaryotic microorganisms is established and evidence of predation on smaller prokaryotic microorganisms is beginning to emerge. We studied the retention of both eukaryotic and prokaryotic microbial taxa by wild-caught doliolids in the northern California Current system. We use qPCR to quantify the impact of doliolids on three important and globally abundant taxa: Synechococcus, SAR11 and diatoms. Doliolids were collected during bloom events identified at three different shelf locations with variable upwelling intensities. We discovered that in addition to eukaryotic phytoplankton, doliolids feed on a range of prokaryotic microbial functional groups. Prey included pelagic Archaea, Pelagibacter, and picocyanobacteria, expanding our understanding of doliolid feeding to the smallest and most numerous microbial community members of the ocean. We also found that doliolids retain SAR11, which is intriguing because some SAR11 lineages may evade predation by other benthic and pelagic tunicates through their surface properties. Given the ability of doliolids to clear large portions of seawater by filtration and their high abundance in this system, we suggest that doliolids are an important player in shaping microbial community structure, primary production, and carbon fate in an ecologically and economically important fisheries system
Production of a videotape series to promote forage-based livestock production in the Upper Midwest
Although properly managed grazing can increase farm income and enhance environmental quality, it has not been widely used in the Upper Midwest. Instead, grazing has been viewed as an adjunct to row crop production, and state-of-the-art management techniques have been adopted slowly. However, recent research has developed forage grazing systems that can compete economically with row crops, especially on more erodible land. In order to implement such systems successfully, producers need practical information on the technical aspects of grazing and pasture management. Most grazing videos produced prior to this project were tailored to other geographic regions or weren\u27t sufficiently detailed. The five videotapes produced in this project cover controlled grazing, principles for managing pasture plants, animal management, fencing and water systems, and year-round systems for the Upper Midwest
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