1,556 research outputs found
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
ECONOMICS OF ALTERNATIVE STOCKING DENSITIES FOR DIRECT-SEEDED CENTRAL MICHIGAN ALFALFA PASTURES
A framework which permits estimation of economically optimal stocking rates for alternative economic parameters and alfalfa forage availability was developed and applied to a controlled grazing experiment conducted with Holstein steers (243 kg) placed on direct seeded alfalfa pastures in Central Michigan. Responses of ADG to alternative levels of forage availability per standard livestock unit (FA) were summarized by a quadratic function and the associated gains/ha were calculated. The ADG decreased as standard stocking rate (SSR; SLU/ha) increased except for the combination of the lowest observed SSR and highest FA, where ADG was curvilinear as SSR increased. The trend for gain/ha was curvilinear for all FA. The SSR which maximized gain/ha increased with FA and was greater than that which maximized ADG. Net returns to fixed resources(NRFR)/ha ($/ha)were calculated for alternative SSR and the economically optimal SSR were identified under various levels of herbage mass (kg/d). The SSR's which maximized NRFR were between the SSR's which maximized ADG and gain/ha. The magnitude of the sale price discount for heavier weight calves (slide) influenced the economically optimal SSR and the sensitivity of net return to SSR. The economically optimal SSR increased as slide increased because animals stocked under higher SSR weighed less off pasture and therefore received less price discount.Crop Production/Industries,
Human-Automation Path Planning Optimization and Decision Support
Path planning is a problem encountered in multiple domains, including unmanned vehicle control, air traffic control, and future exploration missions to the Moon and Mars. Due to the voluminous and complex nature of the data, path planning in such demanding environments requires the use of automated planners. In order to better understand how to support human operators in the task of path planning with computer aids, an experiment was conducted with a prototype path planner under various conditions to assess the effect on operator performance. Participants were asked to create and optimize paths based on increasingly complex path cost functions, using different map visualizations including a novel visualization based on a numerical potential field algorithm. They also planned paths under degraded
automation conditions. Participants exhibited two types of analysis strategies,
which were global path regeneration and local sensitivity analysis. No main effect due to visualization was detected, but results indicated that the type of optimizing cost function affected performance, as measured by metabolic costs, sun position, path distance and task time. Unexpectedly, participants were able to better optimize more complex cost functions as compared to a simple time-based cost function.We would like to acknowledge the NASA Harriett G. Jenkins Predoctoral Fellowship, the American Association of University Women (AAUW) Dissertation Fellowship, and the Office of Naval Research for sponsoring this research
Supervised vs. Unsupervised Learning for Operator State Modeling in Unmanned Vehicle Settings
In this paper, we model operator states using hidden Markov models applied to human supervisory control behaviors. More specifically, we model the behavior of an operator of multiple heterogeneous unmanned vehicle systems. The hidden Markov model framework allows the inference of higher operator states from observable operator interaction with a computer interface. For example, a sequence of operator actions can be used to compute a probability distribution of possible operator states. Such models are capable of detecting deviations from expected operator behavior as learned by the model.The difficulty with parametric inference models such as hidden Markov models is that a large number of parameters must either be specified by hand or learned from example data.We compare the behavioral
models obtained with two different supervised learning techniques and an unsupervised hidden Markov model training technique. The results suggest that the best models of human supervisory control behavior are obtained through unsupervised learning. We conclude by presenting further extensions to this work.This research was supported by Boeing Phantom Works
Rural, Suburban and Urban Voters: Dissecting Residence Based Voter Cleavages in Provincial Elections
We explore provincial-level cleavages by drawing on surveys administered during eight elections. More specifically, we examine rural-suburban-urban divisions in regards to party support within Canadian provinces. Our results show a clear division according to place of residence, even after controlling for a host of individual-level characteristics. We argue that recognition of this rural-suburban-urban division is an important and often overlooked aspect of understanding Canadian political preferences and political behaviour more generally
Photonic realization of the relativistic Kronig-Penney model and relativistic Tamm surface states
Photonic analogues of the relativistic Kronig-Penney model and of
relativistic surface Tamm states are proposed for light propagation in fibre
Bragg gratings (FBGs) with phase defects. A periodic sequence of phase slips in
the FBG realizes the relativistic Kronig-Penney model, the band structure of
which being mapped into the spectral response of the FBG. For the semi-infinite
FBG Tamm surface states can appear and can be visualized as narrow resonance
peaks in the transmission spectrum of the grating
Four-year assessment of ambient particulate matter and trace gases in the Delhi-NCR region of India
A key challenge in controlling Delhi’s air quality is a lack of clear understanding of the impacts of emissions from the surrounding National Capital Region (NCR). Our objectives are to understand the limitations of publicly available data, its utility to determine pollution sources across Delhi-NCR and establish seasonal profiles of chemically active trace gases. We obtained the spatiotemporal characteristics of daily-averaged particulate matter (PM10 and PM2.5) and trace gases (NOX, O3, SO2, and CO) within a network of 12 air quality monitoring stations located over 2000 km2 across Delhi-NCR from January 2014 to December 2017. The highest concentrations of pollutants, except O3, were found at Anand Vihar compared with lowest at Panchkula. A high homogeneity in PM2.5 was observed among Delhi sites as opposed to a high spatial divergence between Delhi and NCR sites. The bivariate polar plots and k-means clustering showed that PM2.5 and PM10 concentrations are dominated by local sources for all monitoring sites across Delhi-NCR. A consequence of the dominance of local source contributions to measured concentrations, except to one site remote from Delhi, is that it is not possible to evaluate the influence of regional pollution transport upon PM concentrations measured at sites within Delhi and the NCR from concentration measurements alone
Efeito do tratamento com soda cáustica e suplementação protéica de feno de Paspalum dilatatum no consumo e ganho de peso de bovinos
Mature Paspalum dilatatum hay was baled untreated, or sprayed with a solution supplying 12 g N and 1,2 g S/kg forage, as urea and NaHSO4, respectively, with and without the addition of caustic soda (40 g NaOH/kg forage). Sprayed forage was left in a moist condition in windrows for 24 hours before tedding and baling. Forages were chopped into 5-10 cm length and offered ad lib. to 40 Hereford streers and heifers housed in individual stalls and allocated to five treatments as follows: A) untreated hay; B) N + S; C) N + S + 300 g meat meal/head/day; D) N + S plus sodium hydroxide; E) N + S plus sodium hydroxide plus 300 g meat meal/head/day. Animals on treatment A suffered muscular trembling and ataxia and were removed from the trial. Liveweights were recorded twice weekly over 44 days and liveweight changes calculated as the coefficients of liveweight regressed against time. Liveweight gains did not differ significantly, being 471, 474, 547 and 525 g/head/day on treatments B, C, D and E, respectively. Voluntary dry matter intakes were higher on treatments D and E than on treatments B and C (D, E > B, C; P B, C; P < 0,05), sendo 4,18; 3,93; 3,62 e 3,73 kg/cab/dia, respectivamente. A digestibilidade da matéria seca (DMS) in vivo foi semelhante em todos os tratamentos (52%)
Systematic study of the effect of short range correlations on the form factors and densities of s-p and s-d shell nuclei
Analytical expressions of the one- and two-body terms in the cluster
expansion of the charge form factors and densities of the s-p and s-d shell
nuclei with N=Z are derived. They depend on the harmonic oscillator parameter b
and the parameter which originates from the Jastrow correlation
function. These expressions are used for the systematic study of the effect of
short range correlations on the form factors and densities and of the mass
dependence of the parameters b and . These parameters have been
determined by fit to the experimental charge form factors. The inclusion of the
correlations reproduces the experimental charge form factors at the high
momentum transfers (). It is found that while the parameter
is almost constant for the closed shell nuclei, He, O and
Ca, its values are larger (less correlated systems) for the open shell
nuclei, indicating a shell effect in the closed shell nuclei.Comment: Latex, 21 pages, 6 figures, 1 tabl
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