STUDI IDENTIFIKASI KERAGAMAN JENIS, DAN KELIMPAHAN FITOPLANKTON DAN PLANKTON BERACUN SERTA STATUS TROFIK PERAIRAN PANTAI SELABIH

Wilayah pesisir atau wilayah pantai dan lautan adalah suatu kawasan yang sangat strategis baik ditinjau dari segi ekologi, sosial budaya, dan ekonomi. Semakin menurunnya kualitas dan kuantitas kawasan pesisir di beberapa daerah di Indonesia, kawasan pesisir di Kabupaten Tabanan bagian barat khususnya di pantai Selabih. Tujuan penelitian adalah mengetahui kondisi biologis dan produktivitas primer Pantai Selabih dilihat dari parameter : Keragaman jenis phytoplankton dan plankton beracun di perairan pantai Selabih, Komposisi jenis phytoplankton dan plankton beracun di masing-masing stasiun dan setiap periode pengamatan. Status tropik perairan. Hasil penelitian menunjukkan bahwa keragaman hayati jenis phytoplankton dan plankton beracun di sepanjang Pantai Selabih, Kabupaten Tabanan khususnya pada stasiun pengambilan sampel mempunyai jenis keragaman yang relative tinggi, maka secara keseluruhan ditemukan 6 kelas phytoplankton yaitu kelas Diatome, Desmidiacae, Xanthophyta, Euglenophyta, Chrysophycae, dan Phyrophyta, Dengan 13 jenis species yaitu : dari kelas Diatome 5 species (Diatoma vulgare, Thallssiothrix sp, Liomophora lingbyoi, Amphiprora gigantean, : Nitzchina sp.). dari kelas Desmidiacae 2 species (Cosmarium cucurbitimun, Penium spirostriolatum,). Dari kelas Xanthophycae 1 species (Batryyococcus braunii), dari kelas Euglenophyta 1 species (Phacus anomale), dari kels Phyropita 4 (Gonyaulax polyedra, Gymnodinum costatum, Peridenium crasipen, Warworia fusus). Komposisi jenis pitoplankton dan plankton beracun pada setipa periode pengamatan di masing-masing stasiun berubah-ubah dari waktu kewaktu. Kelimpahan fitoplankton dan plankton yang beracun, berbeda-beda pada setiap stasiun. Pada setiap periode pengamatan di masing-masing stasiun juga menunjukkan kelimpahan yang berbeda-beda. Secara keseluruhan puncak kelimpahan yang tertinggi terjadi pada stasiun I (satu) yaitu 92.454 ind/liter, dan plankton beracun 66.038 ind/liter, sedangkan pada stasiun V (lima) puncak kelimaphan tertinggi yaitu 29.451 ind/liter, sedangkan plankton beracun 13.208 ind/liter. Hal ini menunjukkan bahwa pada stasiun I memiliki tingkat kesuburan perairan yang paling tinggi, akibat dari bermuaranya sungai yang cukup besar di stasiun ini yaitu tukad Yeh Leh, sedangkan stasiun yang lainnya hanya bermuara sungai-sungai kecil. Walaupun kelimpahan fitoplanton berbeda-beda di masing-masing stasiun dan setiap periode pengamatna, tetapi dari status tropik perairan semuanya berada pada perairan dari mesotrofik sampai politrofik, dan tidak pernah terjadi sampai status oligotropik, yaitu kelimpahan terendah yang terjadi di stasiun V yaitu 13.208 inde/liter masih tergolong mesotrofik

Ototoxicidade dos antibióticos aminoglicosídeos e sistema eferente: comparação entre a administração aguda e crônica com gentamicina e os efeitos agudos de outros antibióticos

OBJECTIVES: 1) To review the global base activity of the auditory nerve, the medial efferent olivocochlear system and the effect of aminosydes; 2) to investigate theblocking effect of gentamicin against the contralateral efferent supression of the ipsilateral cochlear activity using doses below 150 mg/kg; 3) to verify if this effectcould constitute an early sign of ototoxicity during a chronic treatment with gentamicin (60 mg/kg i.m. for 10 days); and 4) to determine if others aminosydes would have the same acute effects of gentamicin and if there would be a correlation between its specificities and ototoxicity degree and its potential to block the medial efferent system.MATERIALS AND METHODS: To test the function of the medial efferent olivocochlear system, the base electrical activity of the auditory nerve was tested in guinea pigsbefore and during a low contralateral acoustic stimulation intensity (55 dB SPL).RESULTS: Results show a dose-dependent effect of gentamicin on contralateral supression.The 120 mg/kg dose of gentamicin induced a smaller block of the medial efferent system compared to the 150 mg/kg, and no block was observed in smaller doses. During chronic treatment, no alteration either in the base activity of the auditory nerve without acoustic stimulation or in contralateral efferent supression was verified.The guinea pigs, monitored for several weeks after chronic treatment, presented a progressive reduction of the base activity of the auditory nerve without contralateral stimulation, in addition to a reduction in the coefficient of base activity suppressionand an increase in auditory limits, suggesting impairment of the cochlear function.CONCLUSION: Our results suggest that chronic gentamicin treatment (60 mg/kg), although ototoxic, does not affect contralateral efferent suppression, at least before the development of ototoxicity.OBJETIVOS: 1) Revisar a atividade de base global do nervo auditivo, sistema olivococlear eferente medial e efeito dos aminosídeos; 2) investigar o efeito bloqueador da gentamicina à supressão eferente contralateral da atividade coclear ipsilateral utilizando doses inferiores à 150 mg/kg; 3) verificar se este efeito poderia constituir um sinal antecipatório de ototoxicidade durante um tratamento crônico com gentamicina (60 mg/kg i.m. durante 10 dias); e 4) determinar se outros aminosídeos teriam os mesmos efeitos agudos que a gentamicina e se haveria uma correlação entre suas especificidades e graus de ototoxicidade e suas potências de bloqueio do sistemaeferente medial.MATERIAIS E MÉTODOS: A função do sistema eferente olivococlear medial foi testada em cobaias pelo registro da atividade elétrica de base do nervo auditivo, antes edurante uma estimulação acústica contralateral de baixa intensidade (55 dB SPL).RESULTADOS: Os resultados mostram um efeito dose-dependente da gentamicina na supressão contralateral, uma vez que uma dose de 120 mg/kg de gentamicinainduziu um menor bloqueio do sistema eferente medial comparado a 150 mg/kg, e nenhum bloqueio foi observado com doses inferiores. Durante o tratamento crônico, nenhuma alteração da atividade de base do nervo auditivo sem estimulação acústica ou da supressão eferente contralateral foi verificada. As cobaias monitoradas durante várias semanas após o tratamento crônico apresentaram uma redução progressiva da atividade de base do nervo auditivo sem estimulação contralateral, além de uma redução dos coeficientes de supressão da atividade de base e elevação dos limiares auditivos, denotando uma função coclear injuriada.CONCLUSÃO: O estudo demonstrou que um tratamento crônico com 60 mg/kg de gentamicina, apesar de ototóxico, não afeta a supressão eferente contralateral, pelo menos antes do desenvolvimento da ototoxicidade

Convergence of the critical attractor of dissipative maps: Log-periodic oscillations, fractality and nonextensivity

For a family of logistic-like maps, we investigate the rate of convergence to the critical attractor when an ensemble of initial conditions is uniformly spread over the entire phase space. We found that the phase space volume occupied by the ensemble W(t) depicts a power-law decay with log-periodic oscillations reflecting the multifractal character of the critical attractor. We explore the parametric dependence of the power-law exponent and the amplitude of the log-periodic oscillations with the attractor's fractal dimension governed by the inflexion of the map near its extremal point. Further, we investigate the temporal evolution of W(t) for the circle map whose critical attractor is dense. In this case, we found W(t) to exhibit a rich pattern with a slow logarithmic decay of the lower bounds. These results are discussed in the context of nonextensive Tsallis entropies.Comment: 8 pages and 8 fig

Comparative adventitious root development in pre-etiolated and flooded Arabidopsis hypocotyls exposed to different auxins

Adventitious roots (ARs) emerge from stems, leaves or hypocotyls, being strategic for clonal propagation. ARs may develop spontaneously, upon environmental stress or hormonal treatment. Auxins strongly influence AR development (ARD), depending on concentration and kind. However, the role of different types of auxin is rarely compared at the molecular level. Rooting triggered by light exposure and flooding was examined in intact etiolated Arabidopsis thaliana hypocotyls treated with distinct auxin types. Morphological aspects, rooting-related gene expression profiles, and IAA immunolocalization were recorded. NAA and 2,4-D effects were highly dose-dependent; at higher concentrations NAA inhibited root growth and 2,4-D promoted callus formation. NAA yielded the highest number of roots, but inhibited elongation. IAA increased the number of roots with less interference in elongation, yielding the best overall rooting response. IAA was localized close to the tissues of root origin. Auxin stimulated ARD was marked by increased expression of PIN1 and GH3.3. NAA treatment induced expression of CYCB1, GH3.6 and ARF8. These NAA-specific responses may be associated with the development of numerous shorter roots. In contrast, expression of the auxin action inhibitor IAA28 was induced by IAA. Increased PIN1 expression indicated the relevance of auxin efflux transport for focusing in target cells, whereas GH3.3 suggested tight control of auxin homeostasis. IAA28 increased expression during IAA-induced ARD differs from what was previously reported for lateral root development, pointing to yet another possible difference in the molecular programs of these two developmental processes.Plant science

The signed loop approach to the Ising model: foundations and critical point

The signed loop method is a beautiful way to rigorously study the two-dimensional Ising model with no external field. In this paper, we explore the foundations of the method, including details that have so far been neglected or overlooked in the literature. We demonstrate how the method can be applied to the Ising model on the square lattice to derive explicit formal expressions for the free energy density and two-point functions in terms of sums over loops, valid all the way up to the self-dual point. As a corollary, it follows that the self-dual point is critical both for the behaviour of the free energy density, and for the decay of the two-point functions.Comment: 38 pages, 7 figures, with an improved Introduction. The final publication is available at link.springer.co

Anisotropy in the Hubble constant as observed in the HST Extragalactic Distance Scale Key Project results

Based on general relativity, it can be argued that deviations from a uniform Hubble flow should be thought of as variations in the Universe's expansion velocity field, rather than being thought of as peculiar velocities with respect to a uniformly expanding space. The aim of this paper is to use the observed motions of galaxies to map out variations in the Universe's expansion, and more importantly, to investigate whether real variations in the Hubble expansion are detectable given the observational uncertainties. All-sky maps of the observed variation in the expansion are produced using measurements obtained along specific lines-of-sight and smearing them across the sky using a Gaussian profile. A map is produced for the final results of the HST Extragalactic Distance Scale Key Project for the Hubble constant, a comparison map is produced from a set of essentially independent data, and Monte Carlo techniques are used to analyse the statistical significance of the variation in the maps. A statistically significant difference in expansion rate of 9 km/s/Mpc is found to occur across the sky. Comparing maps of the sky at different distances appears to indicate two distinct sets of extrema with even stronger statistically significant variations. Within our supercluster, variations tend to occur near the supergalactic plane, and beyond our supercluster, variations tend to occur away from the supergalactic plane. Comparison with bulk flow studies shows some concordance, yet also suggests the bulk flow studies may suffer confusion, failing to discern the influence of multiple perturbations.Comment: 23 pages, 5 figures, to be published in New Astronom