13,383 research outputs found
Interactions between Small Inorganic Ions and Uncharged Monolayers on the Water/Air Interface.
The interaction of several simple electrolytes with uncharged insoluble monolayers is studied on the basis of tensiometric and potentiometric data for the surface electrolyte solution|air. The induced adsorption of electrolyte on the monolayer is determined via a combination of data for equilibrium spreading pressure and surface pressure versus area isotherms. We show that the monolayer-induced adsorption of electrolyte is not only strongly ion-specific but also surfactant-specific. The comparison between the ion-specific effects on a carboxylic acid monolayer at low pH and an ester monolayer shows that the anion series follows the same order while the cation series reverses. The effect of the electrolyte on the chemical potential of the monolayer shows attraction between the surfactant and the ions at low monolayer densities, but at high surface densities, repulsion seems to come into play. In nearly all investigated cases, a maximum of monolayer-induced electrolyte adsorption is observed at intermediate monolayer densities. This suggests specific interactions between the surfactant headgroup and the ions. The Volta potential data for the monolayers are analyzed on the basis of the equations of quadrupolar electrostatics. The analysis suggests that the ion-specific effect on the Volta potential is due to the ion-specific decrement of the bulk dielectric constant of the electrolyte solution. Moreover, we present evidence that in most cases the effect of the electrolyte on the orientation of the adsorbed dipoles cannot be neglected. Instead, the change in the ion distribution in the electric double layer seems to have a small effect on the Volta potential
Self-Calibration of Cameras with Euclidean Image Plane in Case of Two Views and Known Relative Rotation Angle
The internal calibration of a pinhole camera is given by five parameters that
are combined into an upper-triangular calibration matrix. If the
skew parameter is zero and the aspect ratio is equal to one, then the camera is
said to have Euclidean image plane. In this paper, we propose a non-iterative
self-calibration algorithm for a camera with Euclidean image plane in case the
remaining three internal parameters --- the focal length and the principal
point coordinates --- are fixed but unknown. The algorithm requires a set of point correspondences in two views and also the measured relative
rotation angle between the views. We show that the problem generically has six
solutions (including complex ones).
The algorithm has been implemented and tested both on synthetic data and on
publicly available real dataset. The experiments demonstrate that the method is
correct, numerically stable and robust.Comment: 13 pages, 7 eps-figure
The value of internal medicine outreach in rural KwaZulu-Natal, South Africa
Background. Sustainable multifaceted outreach is crucial when equity between specialist services available to different sections of South Africa (SA)’s population is addressed. The healthcare disadvantage for rural compared with urban populations is exemplified in KwaZulu-Natal (KZN). Outreach to rural hospitals has reduced the need for patients to undergo journeys to regional or tertiary hospitals for specialist care.Objectives. Multifaceted outreach visits to seven district hospitals in western KZN by a specialist in the Pietermaritzburg Department of Internal Medicine were analysed for the period 2013 - 2014.Methods. Church of Scotland, Vryheid, Dundee, Charles Johnson Memorial, Rietvlei, Estcourt and Greytown hospitals were visited. During each visit, data were collected on data collection forms, including patient numbers, gender and age, whether out- or inpatient, whether referred, and diagnostic categories.Results. During 113 visits, of 1 377 contacts made, 631 were outpatients and 746 were inpatients. Females formed the majority overall, but for inpatients males outnumbered females. The majority of patients were aged >40 years, but over half of inpatients seen were aged ≤40 years. A modest 15% of patients seen were referred to hospitals with specialist services. Overall, cardiovascular disease, predominantly among outpatients, was the biggest diagnostic category. Infectious diseases followed, primarily among inpatients, and then general medicine. No other category reached 10%.Conclusions. The analysis showed differences between diagnostic categories, especially when outpatients and inpatients were separated out. Referral patterns, age-distribution and gender distinctions were made. The value of a good database was confirmed. The multifaceted outreach may have suggested useful outcomes as well as output. The vulnerability v. sustainability of outreach programmes was emphasised
Occurrence of Sperm Abnormality of Beef Cattle at Several Artificial Insemination Centers in Indonesia
In the most species studied sperm abnormalities have long been associated with male infertility and sterility. This study evaluated the sperm morphology (normality and abnormality) of beef cattle at several Artificial Insemination centers in Indonesia. Total of 142 bulls were used in this study; an ejaculate from each bull was examined. A drop of semen was placed on 3-4 glass slides, and smears were prepared and air-dried. The smears were stained with carbolfluchsin-eosin (Williams stain). Types of morphological abnormalities were recorded from 500 cells on each sample. It was recorded that 77.46% samples had low primary sperm abnormalities (10%) was found in 5.63% samples.  Pear shaped was the most frequently type of abnormality found on examined samples (2.24 ± 2.94%); while double head was the lowest (0.01 ± 0.04%). (Animal Production 12(1): 44-49 (2010) Key words : sperm abnormality, beef catlle, artificial insemination cente
Evaluation of subchronic dietary fumonisin B1 on nutrient digestibility and growth performance of rats
Fumonisin B1 (FB1), a toxin produced by Fusarium verticillioides (Fusarium moniliforme) and other Fusarium species which grow on maize worldwide, has been documented to cause various physiological responses in animals. Thirty-nine female Wistar rats randomly assigned to three treatment groups were used to assess the effects of dietary FB1 on nutrient utilization and growth performance. Each group received one of the three diets containing 0.20, 10.0 and 20.0 mg FB1/kg constituting diets 1, 2 and 3, respectively. The animals were weighed weekly and proximate chemical compositions of the diets and the faecal samples collected from the rats on each diet were determined using standard methods. Dietary FB1 significantly (P < 0.05) influenced nutrient digestibility, feed intake, feed conversion efficiency and relative weight gain. Rats fed diets 2 and 3 had relative weight gains of 87.2 and 66.2% of the rats fed diet 1, respectively. Rats on diet 1 were about 104.5 and 160.6% more efficient in feed conversion compared to those on diets 2 and 3, respectively. Dietary exposure to FB1 at a concentration of about 10 mg/kg or higher for a period of 35 days is a potential health risk that reduced nutrient utilization by adversely affecting proper nutrient digestion, absorption and/or metabolism, resulting in poor growth rates in Wistar rats. This study revealed that adverse effects of FB1 on nutrient digestibility and utilization play a significant contributory role in poor growth performance usually associated with animals exposed to diets containing FB1.Key words: Fumonisin B1, growth performance, mycotoxin, nutrient digestibility, rats
Akumulasi Kromium (Cr) Pada Daging Ikan Nila Merah (Oreochromis Ssp.) Dalam Karamba Jaring Apung Di Sungai Winongo YOGYAKARTA
Sungai Winongo merupakan salah satu sungai penting di Yogyakarta, karena berperan dalam menunjang dan memenuhi kebutuhan hidup masyarakat sekitarnya. Tujuan penelitian ini adalah mengetahui kandungan logam berat kromium (Cr) pada air dan daging ikan nila merah di Sungai Winongo Yogyakarta serta mengetahui kelayakannya untuk dikonsumsi. Penelitian menggunakan rancangan eksplorasi dengan metode survai, dengan penetapan pengambilan sampel menggunakan teknik Purposive Random Sampling. Metode analisis uji kandungan logam berat Cr pada air dan ikan nila merah menggunakan AAS. Konsentrasi Cr pada air di Sungai Winongo Yogyakarta adalah 0,0213 mg/L, nilai ini masih berada di bawah ambang batas yang sudah ditetapkan PPRI No. 82 Tahun 2001 yakni sebesar 0,05 mg/L. Pada ikan nila merah diketahui akumulasi tertinggi pada stasiun 1 sebesar 10,2265 mg/Kg; kemudian pada stasiun 3 dan 2 sebesar 9,81075 mg/Kg dan 9,2245 mg/Kg. Nilai ini melebihi baku mutu yang sudah ditetapkan oleh Dirjen POM 1989 yakni sebesar 2,5 mg/Kg. Simpulan dari penelitian ini adalah kandungan Cr dalam air masih di bawah ambang batas. Ikan nila merah di sungai Winongo sudah mengakumulasi Cr di atas ambang batas, sehingga tidak layak konsumsi.Winongo river is one of the important rivers in Yogyakarta because this supports and fulfils the people's needs. The purpose of this study was to determine the heavy metal content of Cr in water and red tilapia fish meat captured in Winongo Yogyakarta and to know whether the meat is edible or not. The study design was used exploration design with survey method, in which the determination of sampling was using purposive random sampling. Method of test analysis of heavy metals Cr in water and red tilapia was using AAS. Chromium concentration in water of Winongo river was 0.0213 mg/l, this value remains below the threshold set by PPRI No. 82 year 2001 which was 0.05 mg/L, the highest accumulation of Cr in red tilapia meat was at station 1 i.e. 10.2265 mg/Kg; followed by station 3 and 2 by 9.8108 mg/Kg and 9.2245 mg/Kg, respectively. Thiese values exceed the standard quality set forth by the Director General of POM in 1989 i.e. 2.5 mg/Kg. The conclusion was that Cr content in the water is still below the threshold but Tilapia fishes in Winongo river accumulated Cr above the threshold, so that people better not consume red tilapia fish
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Low-temperature formation of polycyclic aromatic hydrocarbons in Titan’s atmosphere
The detection of benzene in Titan’s atmosphere led to the emergence of polycyclic aromatic hydrocarbons (PAHs) as potential nucleation agents triggering the growth of Titan’s orange-brownish haze layers. However, the fundamental mechanisms leading to the formation of PAHs in Titan’s low-temperature atmosphere have remained elusive. We provide persuasive evidence through laboratory experiments and computations that prototype PAHs like anthracene and phenanthrene (C14H10) are synthesized via barrierless reactions involving naphthyl radicals (C10H7•) with vinylacetylene (CH2=CH–C≡CH) in low-temperature environments. These elementary reactions are rapid, have no entrance barriers, and synthesize anthracene and phenanthrene via van der Waals complexes and submerged barriers. This facile route to anthracene and phenanthrene—potential building blocks to complex PAHs and aerosols in Titan—signifies a critical shift in the perception that PAHs can only be formed under high-temperature conditions, providing a detailed understanding of the chemistry of Titan’s atmosphere by untangling elementary reactions on the most fundamental level
Occurrence of Sperm Abnormality of Beef Cattle at Several Artificial Insemination Centers in Indonesia
In the most species studied sperm abnormalities have long been associated with male infertility and sterility. This study evaluated the sperm morphology (normality and abnormality) of beef cattle at several Artificial Insemination centers in Indonesia. Total of 142 bulls were used in this study; an ejaculate from each bull was examined. A drop of semen was placed on 3-4 glass slides, and smears were prepared and air-dried. The smears were stained with carbolfluchsin-eosin (Williams stain). Types of morphological abnormalities were recorded from 500 cells on each sample. It was recorded that 77.46% samples had low primary sperm abnormalities (10%) was found in 5.63% samples. Pear shaped was the most frequently type of abnormality found on examined samples (2.24 ± 2.94%); while double head was the lowest (0.01 ± 0.04%). (Animal Production 12(1): 44-49 (2010
Influence des perturbations anthropiques sur la biodiversité des bois sacrés du Centre Bénin
Le Centre Bénin couvre les Communes de Glazoué, de Savè et de Ouèssè. L’étude a ciblé 61 bois sacrés autour desquels des entretiens ont été réalisés avec les populations riveraines. A cet effet, 244 personnes de façon raisonnée ont été interrogées. Ces entretiens ont permis de savoir que les valeurs traditionnelles, culturelles, alimentaires et thérapeutiques ont un intérêt pour les communautés. Les différents entretiens avec les populations locales ont permis de comprendre qu’elles accordent du prix aux bois sacrés. Ces lieux sacrés constituent l’habitat des espèces animales et végétales rares et menacées de disparition. Les interdits liés à ces bois sacrés permettent de conserver leur biodiversité. Les relevés phytosociologiques réalisés sur des placettes de 30 m x 30 m ont permis de savoir que 47% des bois sacrés sont sous pression pastorale. Dans ces bois sacrés, 7 espèces (Afzelia africana , Borassus aethiopum,Khaya senegalensis, Milicia excelsa, Ptereocarpus erinaceus, Vitellaria paradoxa et Zanthoxylum zanthozyloides) sont sur la liste rouge de l’UICN. Le statut des espèces au Bénin montre que 4 espèces sont en danger et 3 espèces sont vulnérables. Dans ces bois sacrés, 12 espèces animales et 25 espèces floristiques sont citées dans le traitement de certaines maladies. © 2013 International Formulae Group. All rights reserved.Mots clés: Communautés, bois sacrés, valeurs culturelles, maladies, Centre Bénin
Improving hyperspectral band selection by constructing an estimated reference map
We investigate band selection for hyperspectral image classification. Mutual information (MI) measures the statistical dependence between two random variables. By modeling the reference map as one of the two random variables, MI can, therefore, be used to select the bands that are more useful for image classification. A new method is proposed to estimate the MI using an optimally constructed reference map, reducing reliance on ground-truth information. To reduce the interferences from noise and clutters, the reference map is constructed by averaging a subset of spectral bands that are chosen with the best capability to approximate the ground truth. To automatically find these bands, we develop a searching strategy consisting of differentiable MI, gradient ascending algorithm, and random-start optimization. Experiments on AVIRIS 92AV3C dataset and Pavia University scene dataset show that the proposed method outperformed the benchmark methods. In AVIRIS 92AV3C dataset, up to 55% of bands can be removed without significant loss of classification accuracy, compared to the 40% from that using the reference map accompanied with the dataset. Meanwhile, its performance is much more robust to accuracy degradation when bands are cut off beyond 60%, revealing a better agreement in the MI calculation. In Pavia University scene dataset, using 45 bands achieved 86.18% classification accuracy, which is only 1.5% lower than that using all the 103 bands
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