3,449 research outputs found

    Tidal exchange of larvae of Sesarma catenata (Decapoda, Brachyura) in the Swartkops estuary, South Africa

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    The tidal exchange of larvae of the salt-marsh grapsid crab Sesarma catenata was studied in the Swartkops estuary, a tidally driven, shallow estuary in Algoa Bay, South Africa. Plankton samples were collected bimonlhly during spring and neap tides from October to March at the tidal inlet. Samples were collected hourly for 25 h in February, and for 13 h in all other months. Hourly estimates of water flux through the tidal inlet of lhe esluary were calculaled using a generalized one-dimensional hydrodynamic model calibrated for lhe Swartkops estuary. Water flux estimates were used to calculate larval flux through the tidal inlet, Zoea I larvae of Sesarma catenata were found in all sampling sessions, with highest abundance during nocturnal ebb tides. Two seasonal peaks of abundance were detected in November and February-March. These coincided with recorded peaks of percentage abundance of gravid females in the adult population. Megalopa larvae were recorded mainly during flood tides from January to March. More than 70 % of all Sesarma catenata larvae moving through the tidal inlet of the Swartkops estuary in either direction were exported in any given sampling session. There was net export of zoea l larvae in all cases but one, and net import of megalopa larvae in all cases. The possibility that Sesarma catenata larvae may become entrapped in lhe surf zone circulation system throughout development, as a mechanism to avoid offshore dispersal, is discussed

    The zoeal development of Sesarma eulimene de Man (Decapoda, Brachyura, Grapsidae), and identification of larvae of the genus Sesarma in South African waters

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    The five zoea larval stages of the estuarinecrab Sesarma eulimene de Man 1897 (Brachyura, Grapsidae) are described in detail from specimens reared in the laboratory. The morphology of larval Grapsidae is briefly discussed and an updated summary of larval diagnostic characters in the genus Sesarma is given as an aid to identifying specimens in plankton samples from Soulh African waters

    Larval development of Sesarma catenata Ortmann (Brachyura, Grapsidae, Sesarminae) reared in the laboratory

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    Sesarma catenata larvae were raised in the laboratory and the development stages described in detail. larval development comprises four zoea and one megalopa stage. Morphological features of the first zoea and megalopa stages of Sesarma catenata are compared with those of other Sesarminae species described in the literature. The genera Sesarma, Metasesarma, and Bresedium appear to be closely related taxa within the subfamily. The diagnostic value of some features of larval morphology is briefly discussed.S. Afr. J. Zool.1987, 22(3

    The larval development of the red mangrove crab Sesarma meinerti de man (Brachyura: Grapsidae) reared in the laborator

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    The larval stages of the red mangrove crab Sesarma meinerti de Man were reared in the laboratory. Larval development consists of five zoeal stages and one megalopa. Zoeal development lasts an average of 25 days at 25°C. The external morphology of larvae is described in detail and their relationship with larvae of congeneric species is briefly discussed

    Compilação dos trabalhos da Embrapa Agroindústria de Alimentos na área de bioenergia nos anos 80.

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    Insect (Arthropoda: Insecta) Composition in the Diet of Ornate Box Turtles (Terrapene ornata ornata) in Two Western Illinois Sand Prairies, with a New State Record for Cyclocephala (Coleoptera: Scarabaeidae)

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    A study of fecal samples collected over a two-year period from juvenile ornate box turtles (Terrapene ornata ornata Agassiz) revealed diets consisting of six orders of insects representing 19 families. Turtles were reared in captivity from eggs harvested from local, wild populations, and released at two remnant prairies. Identifiable insect fragments were found in 94% of samples in 2013 (n=33) and 96% in 2014 (n=25). Frequency of occurrence of insects in turtle feces is similar to results reported in previous studies of midwestern Terrapene species. A comparison of insect composition presented no significant difference between release sites. There is no significant difference in consumed insect species between turtles released into or outside of a fenced enclosure at the same site. Specimens of Cyclocephala longula LeConte collected during this study represent a new state record for Illinois

    Dilution effects in Ho2x_{2-x}Yx_xSn2_2O7_7: from the Spin Ice to the single-ion magnet

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    A study of the modifications of the magnetic properties of Ho2x_{2-x}Yx_xSn2_2O7_7 upon varying the concentration of diamagnetic Y3+^{3+} ions is presented. Magnetization and specific heat measurements show that the Spin Ice ground-state is only weakly affected by doping for x0.3x\leq 0.3, even if non-negligible changes in the crystal field at Ho3+^{3+} occur. In this low doping range μ\muSR relaxation measurements evidence a modification in the low-temperature dynamics with respect to the one observed in the pure Spin Ice. For x2x\to 2, or at high temperature, the dynamics involve fluctuations among Ho3+^{3+} crystal field levels which give rise to a characteristic peak in 119^{119}Sn nuclear spin-lattice relaxation rate. In this doping limit also the changes in Ho3+^{3+} magnetic moment suggest a variation of the crystal field parameters.Comment: 4 pages, 5 figures, proceedings of HFM2008 Conferenc

    A new player in cartilage homeostasis: adiponectin induces nitric oxide synthase type II and pro-inflammatory cytokines in chondrocytes

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    SummaryObjectiveRecent studies revealed a close connection between adipose tissue, adipokines and articular degenerative inflammatory diseases such as rheumatoid arthritis (RA) and osteoarthritis (OA). The goal of this work was to investigate the activity of adiponectin in human and murine chondrocytes and to study its functional role in the modulation of nitric oxide synthase type II (NOS2). For completeness, interleukin (IL)-6, IL-1β, matrix metalloproteinase (MMP)-2, MMP-3, MMP-9, tissue inhibitor of metalloproteinase (TIMP)-1, prostaglandin E2 (PGE2), leukotriene B4 (LTB4), tumor necrosis factor alpha (TNF)-α and monocyte chemoattractant protein-1 (MCP-1) accumulation have been evaluated in adiponectin-stimulated chondrocytes cell culture supernatants.MethodsMurine ATDC5 cell line, C28/I2, C20A4, TC28a2 human immortalized chondrocytes, and human cultured chondrocytes were used. Nitrite accumulation was determined by Griess reaction. Adiponectin receptors (AdipoRs) expression was evaluated by immunofluorescence microscopy and confirmed by reverse transcriptase-polymerase chain reaction. NOS2 expression was evaluated by Western blot analysis whereas cytokines, prostanoids and metalloproteinases production was evaluated by specific enzyme-linked immunosorbent assays.ResultsHuman and murine chondrocytes express functional AdipoRs. Adiponectin induces NOS2. This effect is inhibited by aminoguanidine, dexamethasone and by a selective inhibitor of phosphatidylinositol 3-kinase. In addition, adiponectin is able to increase IL-6, MMP-3, MMP-9 and MCP-1 by murine cultured chondrocytes whereas it was unable to modulate TNF-α, IL-1β, MMP-2, TIMP-1, PGE2 and LTB4 release.ConclusionsThese results bind more closely the interactions between fat-derived adipokines and articular inflammatory diseases, and suggest that adiponectin is a novel key element in the maintenance of cartilage homeostasis which might be considered as a potential therapeutical target in joint degenerative diseases

    The Effects of the Traditional Scaling Technique Versus a Modified Scaling Technique on Muscle Activity and Pinch Force Generation: A Pilot Study

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    Purpose: Dental hygienists perform precision instrumentation tasks repetitively throughout the workday, placing them at increased risk for developing a musculoskeletal disorder. The purpose of this pilot study was to determine differences in muscle activity and pinch force generation between the traditional scaling technique and a modified scaling technique. Methods: A convenience sample of dental hygienists (n=12) acted as their own controls in this counterbalance-designed pilot study. Muscle activity and pinch forces were assessed while participants performed traditional and modified scaling techniques with designated instruments on artificial calculus applied to the lower left quadrant of a typodont, for a period of five minutes. Surface electromyography was used to measure muscle activity; sensors attached to the instrument handle measured pinch forces. Participants were surveyed regarding the instruments used and scaling technique preferences at the conclusion of the session. Parametric and non-parametric tests were used to analyze the data. Descriptive statistics were used to analyze the exit survey. Results: The modified scaling technique required less muscle activity than the traditional technique while scaling, however results were not significant (p \u3e0.05). The traditional scaling technique required greater overall pinch force during scaling (p =.00). Pairwise comparisons revealed significant differences between pinch force generation in the thumb for the two scaling techniques (Z = -2.401, p= 0.016) and in the index finger (Z = -2.223, p= 0.026). The traditional scaling technique generated more pinch force (thumb x = 7.25±4.99, index finger x=2.86±2.14) when compared to the modified scaling technique (thumb x=4.52±2.32, index finger x=1.65±1.28). Participants had a slightly higher preference for the instrument utilized for the modified scaling technique in terms of balance, maneuverability, overall comfort and the associated scaling technique as compared to the instrument utilized for the traditional scaling technique. Conclusion: Use of a modified scaling technique may reduce muscle activity and pinch force generation as compared to the traditional lateral pressure scaling technique during instrumentation. Future research on ergonomic scaling techniques is needed to determine their efficacy and impact on musculoskeletal disorders
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