8,606 research outputs found
Phylogeny Of The Epinephelinae (Teleostei, Serranidae)
Relationships among epinepheline genera are investigated based on cladistic analysis of larval and adult morphology. Five monophyletic tribes are delineated, and relationships among tribes and among genera of the tribe Grammistini are hypothesized. Generic composition of tribes differs from Johnson\u27s (1983) classification only in the allocation of Jeboehlkia to the tribe Grammistini rather than the Liopropomini. Despite the presence of the skin toxin grammistin in the Diploprionini and Grammistini, we consider the latter to be the sister group of the Liopropomini. This hypothesis is based, in part, on previously unrecognized larval features. Larval morphology also provides evidence of monophyly of the subfamily Epinephelinae, the clade comprising all epinepheline tribes except Niphonini, and the tribe Grammistini. Larval features provide the only evidence of a monophyletic Epinephelini and a monophyletic clade comprising the Diploprionini, Liopropomini and Grammistini; identification of larvae of more epinephelines is needed to test those hypotheses. Within the tribe Grammistini, we propose that Jeboehlkia gladifer is the sister group of a natural assemblage comprising the former pseudogrammid genera (Aporops, Pseudogramma and Suttonia). The \u27\u27soapfishes\u27\u27 (Grammistes, Grammistops, Pogonoperca and Rypticus) are not monophyletic, but form a series of sequential sister groups to Jeboehlkia, Aporops, Pseudogramma and Suttonia (the closest of these being Grammistops, followed by Rypticus, then Grammistes plus Pogonoperca). The absence in adult Jeboehlkia of several derived features shared by Grammistops, Aporops, Pseudogramma and Suttonia is incongruous with our hypothesis but may be attributable to paedomorphosis. The generic phylogeny of the Grammistini proposed herein emerges as the single most parsimonious hypothesis largely because of the method chosen for analyzing multistate characters
Phylogeny Of Lampridiform Fishes
A survey of characters defining the Neoteleostei, Eurypterygii, Ctenosquamata, Acanthomorpha, Paracanthopterygii and Acanthopterygii convincingly places the Lampridiformes within the acanthomorph clade. Lampridiforms are primitive with respect to the Percomorpha but their precise placement among basal acanthomorphs remains unclear. In the absence of a specific sister-group hypothesis, Polymixia, percopsiform and beryciform taxa were used as outgroups in a cladistic analysis of the order. Monophyly of Lampridiformes is supported by four apomorphies; three are correlated modifications related to the evolution of a unique feeding mechanism in which the maxilla slides forward with the premaxilla during jaw protrusion. The Veliferidae are the sister group of all other lampridiforms. The deep-bodied (bathysomous) lampridiforms are not monophyletic because Lampris is the sister group of the elongate (taeniosomous) families. Stylephorus is placed as the sister group of all other taeniosomous families. The Radiicephalidae are hypothesized to be the sister group of the Lophotidae, a clade that forms the sister group of the Replecidae + Trachipteridae. Ateleopodid, mirapinnid, and eutaeniiophorid fishes are not lampridiforms. DaggerBajaichthys is allied with living lampridiform fishes but daggerPharmacichthys is not a lampridiform. The affinities of daggerAipichthys and daggerBathysomous are unknown
Larvae Of Diploprion-bifasciatum, Belonoperca-chabanaudi And Grammistes-sexlineatus (Serranidae, Epinephelinae) With A Comparison Of Known Larvae Of Other Epinephelines
Morphology is described for larvae of two species of the epinepheline serranid tribe Diploprionini and one of the tribe Grammistini, and known larvae of other epinephelines are compared. Early stage eggs and development of larvae of Diploprion bifasciatum are described from 144 laboratory-reared specimens, and postflexion larvae of Belonoperca chabanaudi are described from wild-caught specimens. Fourmanoir\u27s (1976) description of postlarval Grammistes sexlineatus is modified and expanded. The second and third dorsal-fin spines of larval D. bifasciatum are remarkably elongate, reaching lengths many times that of the body. These spines are thin and flexible, and each is encased in a sheath of tissue that exhibits patterns of pigment that change ontogenetically. Larvae of Belonoperca have several elongate dorsalfin spines that may attain lengths comparable to those of the second and third dorsal spines of D. bifasciatum; however, only net-collected specimens in which the spines are broken are available. With these descriptions of larval diploprionins, larvae of representatives of all epinepheline tribes are known. Larval epinephelines differ in patterns of pigmentation, head spination, sequence of fin formation and morphology of elongate dorsal spines. The considerable morphological diversity among epinepheline larvae may aid in elucidating the phylogeny of the subfamily
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Age structure of natural versus hatchery-origin endangered Chinook salmon and implications for fisheries management in California
Maturation schedules shape the age structure of a population and influence productivity and exposure to fishing. Fish cultivated and raised in artificial environments such as hatcheries may mature at different ages compared to their natural-origin counterparts. We evaluated whether endangered Sacramento River winter-run Chinook salmon Oncorhynchus tshawytscha produced in a conservation hatchery had different maturation schedules compared to naturalorigin fish, and how any differences affected their exposure to, and impact from, the ocean salmon fishery. Using coded-wire tags collected from hatchery fish in the ocean and in-river fisheries and on the spawning grounds, and scales collected from natural-origin spawner carcasses, we reconstructed the life history of hatchery and natural-origin cohorts from 2002-2015 brood years. Hatchery fish had similar age-2 maturation rates but higher age-3 maturation rates compared to natural-origin fish, resulting in fewer age-4 individuals and an overall more truncated age structure. Because natural-origin winter-run Chinook salmon were more likely to remain at sea until age 4, they were exposed to fishing for an additional year and experienced greater reduction in escapement. Compared to natural-origin males, hatchery-origin males were much less likely to return at an older age, possibly because sexual selection that is occurring on the spawning grounds is not occurring to the same extent in the hatchery. Identifying how reproductive maturation differs across sources, sex, and life histories is critical to understanding how fisheries can disproportionately impact subsets of a population and affect its long-term population dynamics and sustainability
A Perspective of Preconception Health Activities in the United States
Objectives: Information regarding the type and scope of preconception care programs in the United States is scant. We evaluated State Title V measurement and indicator data and abstracts presented at the National Summit on Preconception Care (June 2005) in order to identify existing programs and innovative strategies for preconception health promotion. Methods: We used the web-based Title V Information System to identify state Performance Measures and Priority Needs pertaining to preconception health as reported for the 2005–2010 Needs Assessment Cycle. We also present a detailed summary of the abstracts presented at the National Summit on Preconception Care. Results: A total of 23 states reported a Priority Need that focused on preconception health and health care. Forty-two states and jurisdictions identified a Performance Measure associated with preconception health or a related indicator (e.g., folic acid, birth spacing, family planning, unintended pregnancy, and healthy weight). Nearly 60 abstracts pertaining to preconception care were presented at the National Summit and included topics such as research, programs, patient or provider toolkits, clinical practice strategies, and public policy. Conclusions: Strategies for improving preconception health have been incorporated into numerous programs throughout the United States. Widespread recognition of the benefits of preconception health promotion is evidenced by the number of states identifying related indicators
SSN: Shape Signature Networks for Multi-class Object Detection from Point Clouds
Multi-class 3D object detection aims to localize and classify objects of
multiple categories from point clouds. Due to the nature of point clouds, i.e.
unstructured, sparse and noisy, some features benefit-ting multi-class
discrimination are underexploited, such as shape information. In this paper, we
propose a novel 3D shape signature to explore the shape information from point
clouds. By incorporating operations of symmetry, convex hull and chebyshev
fitting, the proposed shape sig-nature is not only compact and effective but
also robust to the noise, which serves as a soft constraint to improve the
feature capability of multi-class discrimination. Based on the proposed shape
signature, we develop the shape signature networks (SSN) for 3D object
detection, which consist of pyramid feature encoding part, shape-aware grouping
heads and explicit shape encoding objective. Experiments show that the proposed
method performs remarkably better than existing methods on two large-scale
datasets. Furthermore, our shape signature can act as a plug-and-play component
and ablation study shows its effectiveness and good scalabilityComment: Code is available at https://github.com/xinge008/SS
Exploring wind direction and SO2 concentration by circular-linear density estimation
The study of environmental problems usually requires the description of
variables with different nature and the assessment of relations between them.
In this work, an algorithm for flexible estimation of the joint density for a
circular-linear variable is proposed. The method is applied for exploring the
relation between wind direction and SO2 concentration in a monitoring station
close to a power plant located in Galicia (NW-Spain), in order to compare the
effectiveness of precautionary measures for pollutants reduction in two
different years.Comment: 17 pages, 7 figures, 2 table
Trends in Students Media Usage
Trends in media usage by students can affect the way they learn. Students demand the use of technology, thus institutions and instructors should meet students’ requests. This paper describes the results of a survey where drivers in the use of media show continuously increasing or decreasing values from the first to the fourth year of study experience at the Western University, Canada, highlighting trends in the usage of new and traditional media in higher education by students. The survey was used to gather data on students’ media usage habits and user satisfaction from first to fourth year of study and found that media usage increases over the years from first to fourth. The presentation of data using bar charts reveals a slight increase over the years in students owning notebooks or laptops off-campus and a significant increase from first to fourth year of students accessing online academic periodicals and journals. Another noteworthy finding relates to fourth year students being more conscious of the quality of information that they read on the Internet in comparison to students in first year, even though this is a slight year on year increase
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