Notes on Loricata (Mollusca) 11-14

NARCIS (Netherlands)

Kaas, P.

1985-01-01

Four new species of chitons (Mollusca, Polyplacophora) are described, viz Leptochiton (L.) dispersus and L. (L.) permodestus from Transkei, L. (L.) meiringae from the eastern Cape Province, S Africa (note 11) and Ischnochiton (Stenosemus) vanbellei from the Mediterranean Sea (note 14). New records

De weekdieren van de Nederlandse brakwatergebieden (Mollusca)

NARCIS (Netherlands)

Kuijper, W.J.

2000-01-01

The molluscs of the brackish waters in the Netherlands (Mollusca) The Netherlands is a river delta rich in brackish waters. The organisms in these waters need to be adapted to extreme conditions, especially large fluctuations in chlorinity. However, several species occur optimally in this habitat.

Atypical feeding behavior of Long-tailed Ducks in the wake of a commercial fishing boat while clamming

Science.gov (United States)

Perry, Matthew; Osenton, Peter C.; White, Timothy P.

2017-01-01

A foraging group of Clangula hyemalis (Long-tailed Duck) was observed on 10 February 2010 diving behind a commercial boat that was clamming near Monomoy Island, Nantucket Sound, MA. We used a shotgun to collect 9 of the ducks, and our analyses of gizzard and gullet (esophagus and proventriculus) revealed 37 food items in the gizzard and 16 in the gullet. Mollusca were the dominant food in the gizzard (49%), whereas Crustacea were dominant in the gullet (57%). Crustacea were the second most important food in the gizzard (38%), whereas Mollusca were the second most important food in the gullet (31%). Relatively high volumes of the Amphipoda Caprella sp. (skeleton shrimp) and the Decopoda Crangon septemspinosa (Sand Shrimp) were recorded in the gullet and gizzard. Ensis directus (Atlantic Jackknife Clam) formed the greatest volume of Mollusca in the gizzard (15%) and in the gullet (15%). Long-tailed Ducks had fed on this Bivalvia and several other species of Mollusca that had no shell or broken shell when consumed. Many of the food organisms were apparently dislodged and some damaged by the clamming operation creating an opportunistic feeding strategy for the Long-tailed Ducks.

Metabolism of 60Co in mollusca

International Nuclear Information System (INIS)

Nakahara, Motokazu

1983-01-01

After mollusca were bred in 60 Co-labeled sea water or were given 60 Co-labeled feed for certain hours, their tissues including the liver were removed as experimental samples. 60 Co metabolism was observed by the Sephadex gel filtration profile. A gel chromatogram of the liver in gastropoda showed a marked peak of 60 Co on the high-molecular side. Although the peak was observed on both high- and low-molecular sides in pelecypoda, it was more marked on the high-molecular side than on the low-molecular side. In cephalopoda, the peak pattern was similar to that in the other mollusca, but the proportion of low-molecular components was comparatively large. The gel filtration profile of 60 Co in various tissues of cephalopoda revealed the incorporation of 60 Co into the high-molecular components in blood, three peaks in the kidneys, and the incorporation of 60 Co into the low-molecular components in the branchial heart. The metabolism of 60 Co was dependent upon the chemical form of Co in gastropoda, and organic 60 Co was specifically observed in the high-molecular components. (Namekawa, K.)

A radioactivity study of mollusca distributed along the Syrian coast

International Nuclear Information System (INIS)

Al-Masri, M. S.; Ammar, I.; Mamish, S.; Haleem, M. A.

2006-10-01

In the present work, radioactivity has been studied in several Mollusca collected from four selected sites(Al Basset, Lattakia, Banise and Tartous) along the Syrian coast. Concentration Factors (CF) of radionuclides (Lead-210, Polonium-210, Uranium Isotopes, Potassium-40 and Cesium-137) in mussels and shells of Mollusca have been calculated in order to determine the species that could be used as Bioindicators for these isotopes. Statistical analysis of the results using the box plot method showed that the mussels of Spondylus spinosus and Chama pacifica can be used as biomonitor for the studied radionuclides in addition to shell of Strombus persicus and Spondylus spinosus. While the mussels of Brachidonta variabilis and Spondylus spinosus have shown good selectivity for Cd and Pb and Pinctada radiate for Zn and Thais haemostoma for Cu. In addition, the migrant Mullusca from the Red Sea, Strombus persicus, can be used as biomonitor for lead, Zn and Cu, Cd, while the shell of Thais haemostoma for lead. However, the importance of the results of the present study that are considered as a baseline data for radionuclides in Mullusca distributed along the Syria coast and it is the only study in the eastern Mediterranean basin, that defined the Mollusca species which could be use as biomonitors for radionuclides. (Authors)

Overwinteringsgedrag van de nauwe korfslak Vertigo angustior (Mollusca)

NARCIS (Netherlands)

Boesveld, A.

2005-01-01

Overwintering habits of the land snail Vertigo angustior (Mollusca) During a mollusc survey in 2004 en 2005 in the province of Zuid-Holland special attention was paid to Vertigo angustior. The species was observed overwintering in large groups, up to hundreds of specimens together, between mosses

Bibliographie der Flussperlmuschel Margaritifera Margaritifera (Linnaeus, 1758) [Mollusca: Pelecypoda

NARCIS (Netherlands)

Jungbluth, J.H.; Coomans, H.E.; Grohs, H.

1985-01-01

Bibliography of the freshwater Pearlmussel Margaritifera margaritifera (Linnaeus, 1758) [Mollusca: Pelecypoda] The freshwater pearlmussel, described by Linnaeus as Mya margaritifera is one of the most important molluscs existing. It belongs with only a few congeneric fossil and recent species to the

A radioactivity study of mollusca distributed along the Syrian coast

International Nuclear Information System (INIS)

Al-Masri, M. S.; Ammar, I.; Mamish, S.; Haleem, M. A.

2008-01-01

In the present work, radioactivity has been studied in several Mollusca collected from four selected sites (Al Basset, Latakia, Banise and Tartous) along the Syrian coast. Concentration Factors (CF) of radionuclides (Lead-210, Polonium-210, Uranium Isotopes, Potassium-40 and Cesium-137) in mussels and shells of Mollusca have been calculated in order to determine the species that could be used as Bioindicators for these isotopes. Statistical analysis of the results using the box plot method showed that the mussels of Spondylus gaederopus spinosus and Chama pacifica can be used as biomonitor for the studied radionuclides in addition to shell of Strombus decorus persicus and Spondylus gaederopus spinosus. While the mussels of Brachidonta variabilis and Spondylus gaederopus spinosus have shown good selectivity for Cd and Pb and Pinctada radiate for Zn and Thais haemostoma for Cu. In addition, the migrant Mullusca from the Red Sea, Strombus decoruspersicus, can be used as biomonitor for lead, Zn and Cu, Cd, while the shell of Thais haemostoma for lead. However, the importance of the results of the present study that are considered as a baseline data for radionuclides in Mullusca distributed along the Syria coast and it is the only study in the eastern Mediterranean basin, that defined the Mollusca species which could be use as biomonitors for radionuclides. (Authors)

De nauwe korfslak Vertigo angustior in Nederland (Mollusca: Gastropoda)

NARCIS (Netherlands)

Bruyne, de R.

2002-01-01

The narrow whorlsnail Vertigo angustior in the Netherlands (Mollusca: Gastropoda) In June and July 2001, a special survey was held in several coastal areas in the province of Zuid- Holland, the Netherlands. The main objective was retrieving additional data on the occurrence of Vertigo angustior

DIVERSITAS DAN KERAPATAN MANGROVE, GASTROPODA DAN BIVALVIA DI ESTUARI PERANCAK, BALI

OpenAIRE

Susiana; Ali, Syamsu Alam; Rukminasari, Nita

2011-01-01

Penelitian ini bertujuan membandingkan diversitas dan kerapatan mangrove dengan kepadatan gastropoda dan bivalvia di mangrove alami dan rehabilitasi. Pengukuran ekosistem mangrove menggunakan transek kuadrat 10 m x 10 m. Kelimpahan dan kepadatan gastropoda dan bialvia menggunakan transek kuadrat berukuran 1 m x 1 m. Analisis nMDS, cluster untuk melihat hubungan karekteristik mangrove alami dan rehabilitasi dianalisis secara deskriptif dan analisis regresi untuk mendetermi...

Types of Cenozoic Mollusca from Java in the Martin Collection of Naturalis

NARCIS (Netherlands)

Leloux, J.; Wesselingh, F.P.

2009-01-01

An updated type catalogue of the Martin Collection (fossil Mollusca, predominantly from the Cenozoic of Java, Indonesia) is presented. Type specimen data, updated locality data, and illustrations are given.

Evaluation of the levels of Br, Cl, K, Mg, Mn and V in Perna perna mussels (Linnaeus, 1758: Mollusca Bivalvia) collected in the coast of Sao Paulo state, Brazil; Avaliacao dos teores de Br, Cl, K, Mg, Mn e V em mexilhoes Perna perna (Linnaeus, 1758: Mollusca Bivalvia) coletados no litoral do estado de Sao Paulo, Brasil

Energy Technology Data Exchange (ETDEWEB)

Seo, Daniele

2012-07-01

The coastal environment has been heavily altered by multiple environmental impacts of human activities, such as disposal of sewage from urban areas, the release of numerous chemical industries, agriculture and the flow of vessels, which can lead to accidental spills of oil and oil products, fuels and other products transported by sea. In this context, a means of determining concentrations of these potentially toxic substances in the sea water is the biomonitoring by means of different types of bivalves, which have been used by various researchers, in Brazil and other countries. With regard to bivalve mollusks, particularly mussels, their use in monitoring the marine contamination is mainly due to their wide geographic distribution, sessile habit and ability to concentrate toxic metals to 102-105 times in relation to the concentrations detected in water. In the present study, we employed the passive biomonitoring using the Perna perna bivalve mollusk with respect to the elements Br, Cl, K, Mg, Mn and V. These elements were chosen since they can be determined by INAA method (Instrumental Neutron Activation Analysis), by means of short irradiation which provides faster analyzes and also due to their importance from the standpoint of environmental or nutritional studies. The aim of this study was to evaluate the content of Br, Cl, K, Mg, Mn and V in samples of Perna perna mussels (Linnaeus, 1758: Mollusca, Bivalvia) collected in coastal regions of Sao Paulo subject to anthropogenic contamination (Ponta de Itaipu and Palmas Island, in Santos), comparing the values obtained in sites potentially impacted with the values of the control site in Praia da Cocanha, in Caraguatatuba. The collection points located in Sao Paulo coast are located in the geographical areas 23 Masculine-Ordinal-Indicator 37'S - 45 Degree-Sign 24' W (Caraguatatuba) and 23 Masculine-Ordinal-Indicator 57'S - 46 Masculine-Ordinal-Indicator 20' W (Santos). The collection of organisms was performed in all

Evaluation of the levels of Br, Cl, K, Mg, Mn and V in Perna perna mussels (Linnaeus, 1758: Mollusca Bivalvia) collected in the coast of Sao Paulo state, Brazil; Avaliacao dos teores de Br, Cl, K, Mg, Mn e V em mexilhoes Perna perna (Linnaeus, 1758: Mollusca Bivalvia) coletados no litoral do estado de Sao Paulo, Brasil

Energy Technology Data Exchange (ETDEWEB)

Seo, Daniele

2012-07-01

The coastal environment has been heavily altered by multiple environmental impacts of human activities, such as disposal of sewage from urban areas, the release of numerous chemical industries, agriculture and the flow of vessels, which can lead to accidental spills of oil and oil products, fuels and other products transported by sea. In this context, a means of determining concentrations of these potentially toxic substances in the sea water is the biomonitoring by means of different types of bivalves, which have been used by various researchers, in Brazil and other countries. With regard to bivalve mollusks, particularly mussels, their use in monitoring the marine contamination is mainly due to their wide geographic distribution, sessile habit and ability to concentrate toxic metals to 102-105 times in relation to the concentrations detected in water. In the present study, we employed the passive biomonitoring using the Perna perna bivalve mollusk with respect to the elements Br, Cl, K, Mg, Mn and V. These elements were chosen since they can be determined by INAA method (Instrumental Neutron Activation Analysis), by means of short irradiation which provides faster analyzes and also due to their importance from the standpoint of environmental or nutritional studies. The aim of this study was to evaluate the content of Br, Cl, K, Mg, Mn and V in samples of Perna perna mussels (Linnaeus, 1758: Mollusca, Bivalvia) collected in coastal regions of Sao Paulo subject to anthropogenic contamination (Ponta de Itaipu and Palmas Island, in Santos), comparing the values obtained in sites potentially impacted with the values of the control site in Praia da Cocanha, in Caraguatatuba. The collection points located in Sao Paulo coast are located in the geographical areas 23 Masculine-Ordinal-Indicator 37'S - 45 Degree-Sign 24' W (Caraguatatuba) and 23 Masculine-Ordinal-Indicator 57'S - 46 Masculine-Ordinal-Indicator 20' W (Santos). The collection of organisms

On fossil Mollusca from the island of Mandul, East-Borneo

NARCIS (Netherlands)

Beets, C.

1950-01-01

This paper presents the results of the examination of a fairly big collection of mollusca from the island of Mandul, north of Tarakan, East-Borneo. The material was collected by Dr. Van Holst Pellekaan while investigating the geology of Mandul in the service of the “Bataafsche Petroleum

Accumulation of cesium-137 by useful mollusca

International Nuclear Information System (INIS)

Suzuki, Yuzuru; Nakahara, Motokazu; Nakamura, Ryoichi

1978-01-01

There are few data available on the radioactive contamination of marine mollusca, especially cephalopoda. Therefore, in this paper, data obtained on the radioactive contamination of cephalopoda were compared with those on pelecypoda and gastropoda. The uptake and elimination experiments were carried out by means of radioisotope tracer methods, and the concentration factors of 137 Cs due to radioactive fallout were estimated. The contamination of cephalopoda was also compared with those of other marine organisms in terms of concentration factor. The activity ratios in the organs or tissues of octopus were in the range of 3.5 and 12.8 on the 14th day after the beginning of exposure and those of squid were in the range of 8.8 and 10.9 on the 6th day after the commencement of the experiment. The biological half time was 90 days for octopus from the observation over 75 days, while it was 31 days for clam from the results of 75 days' experiment. The concentration factors of 137 Cs due to radioactive fallout were in the range of 3 and 23 for cephalopoda, 7 and 28 for pelecypoda and 24 and 30 for gastropoda, respectively. It was concluded that no difference in the concentration factors was clearly observable among the classes of mollusca, but the values were substantially similar to those of crustaceans and slightly lower than those of marine fish. (auth.)

Evaluation of the levels of Br, Cl, K, Mg, Mn and V in Perna perna mussels (Linnaeus, 1758: Mollusca Bivalvia) collected in the coast of Sao Paulo state, Brazil

International Nuclear Information System (INIS)

Seo, Daniele

2012-01-01

The coastal environment has been heavily altered by multiple environmental impacts of human activities, such as disposal of sewage from urban areas, the release of numerous chemical industries, agriculture and the flow of vessels, which can lead to accidental spills of oil and oil products, fuels and other products transported by sea. In this context, a means of determining concentrations of these potentially toxic substances in the sea water is the biomonitoring by means of different types of bivalves, which have been used by various researchers, in Brazil and other countries. With regard to bivalve mollusks, particularly mussels, their use in monitoring the marine contamination is mainly due to their wide geographic distribution, sessile habit and ability to concentrate toxic metals to 102-105 times in relation to the concentrations detected in water. In the present study, we employed the passive biomonitoring using the Perna perna bivalve mollusk with respect to the elements Br, Cl, K, Mg, Mn and V. These elements were chosen since they can be determined by INAA method (Instrumental Neutron Activation Analysis), by means of short irradiation which provides faster analyzes and also due to their importance from the standpoint of environmental or nutritional studies. The aim of this study was to evaluate the content of Br, Cl, K, Mg, Mn and V in samples of Perna perna mussels (Linnaeus, 1758: Mollusca, Bivalvia) collected in coastal regions of São Paulo subject to anthropogenic contamination (Ponta de Itaipu and Palmas Island, in Santos), comparing the values obtained in sites potentially impacted with the values of the control site in Praia da Cocanha, in Caraguatatuba. The collection points located in São Paulo coast are located in the geographical areas 23º 37'S - 45° 24' W (Caraguatatuba) and 23º 57'S - 46º 20' W (Santos). The collection of organisms was performed in all seasons of the year, beginning in spring 2008 and ending in winter 2009. The samples

On six species of marine Mollusca from suriname, four of which are new

NARCIS (Netherlands)

Regteren, van C.O.

1971-01-01

Four new species are here described in order to have their descriptions published before "Seashells of Wia Wia" by D. J. Green & R. H. Hill and the second part of my paper on the Holocene and Recent marine Mollusca of Suriname will appear. Notes are added on two species for which names are used

Determination of protein-carbonyls and ubiquitin-mediated proteolysis as biomarkers of oxidative-stress in bivalvia and anthozoa

International Nuclear Information System (INIS)

Walker, Stephen Thomas

2002-01-01

This study describes the investigation of biomarkers of oxidative-stress in the bivalves Mytilus edulis and Dosinia lupinus, together with host and symbiont tissues of the scleractinian Anthozoa Agaricia agaricites. The biomarkers used were assay of total (via spectrophotometry) and individual (via Western blotting; Oxyblot kit) protein-carbonyls (PC=Os) and content of ubiquitin protein conjugates (UPC) via Western blotting (Bivalvia and Anthozoa) and immunohistochemistry (Anthozoa only). Additional assays for Bivalvia were Trolox equivalent antioxidant capacity (TEAC); and post γ-irradiation survival rates. Experimental stressors for Bivalvia were increased seawater temperature, H 2 O 2 and 60 Co γ-radiation (latter two were used in vivo and in vitro). Comparisons of clean and polluted marine sites are included. Stressors used for Anthozoa were increased solar irradiation concomitant with elevated seawater temperature. Results and conclusions were as follows: individual samples showed considerable variation, pooling of samples improved consistency. Controls for both biomarkers had detectable background levels in each phylum, against which relatively small differences were assessed. In M. edulis, no measurable differences in PC=Os could be determined when elevated seawater temperature or dilute H 2 O 2 ( 2 O 2 (30% v/v) produced a small difference. 60 Co γ-radiation produced clearer differences via Oxyblot and spectrophotometric assays. Comparison of four different tissues from the two bivalves found considerable species-specific and tissue-specific differences. Post-irradiation mortality between species was significantly different (<0.001), D. lupinus was more susceptible than M. edulis. TEAC values generally showed a decrease following irradiation (except for digestive gland). UPCs were clearly different between tissues and between species. PC=Os can be detected by DNPH-reactivity/Western blotting assay in host A. agaricites. UPCs can be assayed via Western

Perfil de lípidos y ácidos grasos de Perna viridis, mejillón verde (Mollusca: Bivalvia en el oriente venezolano y la costa oeste de Trinidad

Directory of Open Access Journals (Sweden)

Tamar Koftayan

2011-03-01

Full Text Available Los lípidos totales fueron extraídos, identificados y cuantificados por gravimetría, mediante TLC/FID (sistema Iatroscan. Los ácidos grasos de los lípidos totales, fosfolípidos y triacilgliceroles fueron identificados y cuantificados por cromatografía de gases. Las mayores concentraciones de lípidos totales se presentaron en las muestras de Los Cedros, La Brea y Chaguaramas con valores de 7.92, 7.74 y 7.53%; respectivamente y los valores mínimos en las de La Restinga (6.08%. En la composición lípidica, las muestras de Chacopata presentaron la menor concentración de fosfolípidos (48.86% y los máximos valores de colesterol (38.87% y triacilgliceroles (12.26%, y las muestras de La Esmeralda y Río Caribe exhibieron concentraciones máximas de fosfolípidos (88.71-84.93%, respectivamente y mínimas de colesterol (6.50-4.42%. En los lípidos totales, los ácidos grasos saturados se encontraron entre 15.04 y 65.55%, con máximos en muestras de La Esmeralda y mínimos en Chacopata y los poliinsaturados estuvieron entre 7.80 y 37.18%, con máximos valores en la Brea y mínimos en la Esmeralda. En los fosfolípidos, la concentración de ácidos grasos saturados estuvo entre 38.81 y 48.68% para las muestras de Chaguaramas y Chacopata, respectivamente; los ácidos grasos poliinsaturados se encontraron entre no detectado y 34.51%, con altas concentraciones en muestras de Los Cedros (27.97% y Chaguaramas (34.51%. En los triacilgliceroles, la composición de ácidos grasos saturados variaron entre 14.27 y 53.80%, con baja concentración en Chacopata y alta concentración en La Restinga; los ácidos grasos poliinsaturados estuvieron entre 4.66 y 35.55%, con valores menores en las muestras de Chacopata (4.66% y mayores en Chaguaramas. El consumo frecuente de Perna viridis es recomendable, debido a su alto contenido de fosfolípidos y ácidos grasos insaturados.Lipid and fatty acid profile of Perna viridis, Green Mussel (Mollusca: Bivalvia in

Determination of protein-carbonyls and ubiquitin-mediated proteolysis as biomarkers of oxidative-stress in bivalvia and anthozoa

Energy Technology Data Exchange (ETDEWEB)

Walker, Stephen Thomas

2002-07-01

This study describes the investigation of biomarkers of oxidative-stress in the bivalves Mytilus edulis and Dosinia lupinus, together with host and symbiont tissues of the scleractinian Anthozoa Agaricia agaricites. The biomarkers used were assay of total (via spectrophotometry) and individual (via Western blotting; Oxyblot kit) protein-carbonyls (PC=Os) and content of ubiquitin protein conjugates (UPC) via Western blotting (Bivalvia and Anthozoa) and immunohistochemistry (Anthozoa only). Additional assays for Bivalvia were Trolox equivalent antioxidant capacity (TEAC); and post {gamma}-irradiation survival rates. Experimental stressors for Bivalvia were increased seawater temperature, H{sub 2}O{sub 2} and {sup 60}Co {gamma}-radiation (latter two were used in vivo and in vitro). Comparisons of clean and polluted marine sites are included. Stressors used for Anthozoa were increased solar irradiation concomitant with elevated seawater temperature. Results and conclusions were as follows: individual samples showed considerable variation, pooling of samples improved consistency. Controls for both biomarkers had detectable background levels in each phylum, against which relatively small differences were assessed. In M. edulis, no measurable differences in PC=Os could be determined when elevated seawater temperature or dilute H{sub 2}O{sub 2} (<30% v/v) stressors were used, nor with between-site comparisons. Concentrated H{sub 2}O{sub 2} (30% v/v) produced a small difference. {sup 60}Co {gamma}-radiation produced clearer differences via Oxyblot and spectrophotometric assays. Comparison of four different tissues from the two bivalves found considerable species-specific and tissue-specific differences. Post-irradiation mortality between species was significantly different (<0.001), D. lupinus was more susceptible than M. edulis. TEAC values generally showed a decrease following irradiation (except for digestive gland). UPCs were clearly different between tissues and

Genetic Population Structure and Demographic History of the Widespread Common Shipworm Teredo navalis Linnaeus 1758 (Mollusca: Bivalvia: Teredinidae in European Waters Inferred from Mitochondrial COI Sequence Data

Directory of Open Access Journals (Sweden)

Ronny Weigelt

2017-06-01

Full Text Available The first documented scientific reports of the common marine shipworm Teredo navalis (Bivalvia for Central European waters date back to the time between 1700 and 1730 in the Netherlands. During the following centuries there were several irregular mass occurrences reported for both the North Sea and the Baltic Sea. These events were accompanied by massive destruction of wooden ships and coastal protection structures. In this study, the first population analysis of T. navalis is presented with the aim to detect the genetic population structure in the waters of Central Europe. The mtDNA COI (cytochrome c oxidase subunit I locus was found as suitable molecular marker and hence a 675 bp gene fragment was studied. A total of 352 T. navalis specimens from 13 different sampling sites distributed across Central Europe were examined. Subsequently, various population genetic indices including FST values and an AMOVA analysis were applied for the description of the population structure. To visualize the distribution of haplotypes at the different sampling sites two median-joining networks were calculated. In addition, the past demographic structure of the T. navalis population was analyzed, among others by calculating Tajima's D, Fu's F and the mismatch distribution. Finally, all computations of the population genetic indices could not reveal differentiated populations or any kind of distinct population structure in T. navalis. The network analyses revealed “star-like” patterns without differentiated substructures or demes. Therefore, it can be assumed that a sudden expansion of this species took place without any indications of neither a bottleneck nor a founder effect for the study area. The results of this study support the concept of a regional panmictic population in the waters of Central Europe with unhindered migration of individuals (e.g., via pelagic larvae between the various sampling sites as reflected by a high gene flow.

Some fossil species of Babylonia seen in ultraviolet light, with description of a new species (Mollusca, Gastropoda)

NARCIS (Netherlands)

Regteren, van C.O.; Gittenberger, E.

1972-01-01

When preparing a revision of the genus Babylonia for "Indo-Pacific Mollusca", edited by Dr. R. Tucker Abbott, we tried ultraviolet light to see the outline of the colour-pattern of some fossil species. Later on we saw the same method described by Mrs. Katherine Krueger (1971). Dr. H. E. Coomans of

Ocorrência do bivalve exótico Mytilopsis leucophaeta (Conrad (Mollusca, Bivalvia, no Brasil Occurrence of exotic bivalve Mytilopsis leucophaeta (Conrad (Mollusca, Bivalvia, in Brazil

Directory of Open Access Journals (Sweden)

José R. B. de Souza

2005-12-01

Full Text Available O molusco Mytilopsis leucophaeta (Conrad, 1831, natural da América do Norte, foi localizado no litoral de Pernambuco, Brasil, em 2004, trazido provavelmente por água de lastro de navios. Na região, sua distribuição atualmente abrange zonas estuarinas adjacentes ao Porto do Recife. Os organismos foram encontrados restritos à região entre-marés, formando agregados densos com até 176.800 ind./m².The mussel Mytilopsis leucophaeta (Conrad, 1831 is native to North America. It was found at Pernambuco Coast, northeastern Brazil, in 2004, probably brought by ships' ballast water. The distribution of this species has been now spread to estuarial area near Recife Harbour. They showed a clumped distribution with a maximum of 176,800 ind./m² only in the intertidal zone.

Gastropoda-Bivalvia Fauna And Neogene-Quaternary Stratigraphy of the Southwest of Dardanelles (Çanakkale-NWAnatolia)

Science.gov (United States)

Kapan, Sevinç; Kabasakal, Sinem

2016-04-01

Gastropoda-Bivalvia Fauna And Neogene-Quaternary Stratigraphy of the Southwest of Dardanelles (Çanakkale-NWAnatolia) Sevinç KAPAN, Sinem KABASAKAL, Çanakkale Onsekiz Mart University, Engineering Faculty, Geological Engineering Department sevinckapan_yesilyurt@hotmail.com In this study, paleontology and stratigraphy of Neogene and Quaternary units around south of the Dardanelles have been examined using Gastropoda and Bivalvia fauna. In the investigation area, the base of the sediments that belongs to Neogene, consist of the volcanics which are formed with basalts, andesites and tuff. Neogene begins unconformity with basal conglomerate which are formed with basalt and tuff gravels. The measurable thickness of the Neogene sediments is approximately 200meters in total. First fossiliferius level which consist of Lymnocardium (Euxinicardium) nobile Sabba has showed similarities with the Pontian (Late Miocene) fauna of the Eastern Paratethys. The existence of Melanopsis and Psidium species indicate that the basin has been brackish water feeding by fresh water in the Early Pliocene. Theodoxus fluviatilis (Linne), Theodoxus (Calvertia) aff. imbricata Brusina, Theodoxus (Calvertia) licherdopoli scriptus (Stefanescu), Viviparus mammatus (Stefanescu), Valvata (Valavata) sulekiana Brusina, Valvata (Cincinna) crusitensis Fontannes, Hydrobia cf grandis Cobalcescu, Hydrobia ventrosa Monfort, Melanopsis (Melanopsis) cf. bergeroni Stefanescu, , Melanopsis (Melanopsis) sandbergeri rumana Tournouer, Melanopsis (Canthidomus) hybostoma anili Taner, Melanopsis (Canthidomus) hybostoma amaradica Fontannes, Melanopsis (Canthidomus) lanceolata Neumayr, Amphimelania fossariformis (Tournouer), Melanoides tuberculata monolithica (Bukowski), Radix (Radix) peregra (Müller), Planorbarius thiollierei (Michaud), Potamida (Potamida) craiovensis craiovensis (Tournouer), Potamida (Potamida) berbestiensis (Fontannes), Unio pristinus davilai Porumbaru, Unio subexquisitus Jatzko, Anadonta zmaji

Modulations in cell-mediated immunity of Mytilus edulis following the 'Sea Empress' oil spill

International Nuclear Information System (INIS)

Dyrynda, E.A.; Dyrynda, P.E.J.; Ratcliffe, N.A.; Pipe, R.K.

1997-01-01

The 'Sea Empress' oil tanker grounded outside Milford Haven (Wales, UK) in February 1996, spilling ∼ 70,000 tonnes of crude oil and contaminating over 100 km of coastline, causing mass mortalities and strandings of at least 11 mollusc species. Intensive field monitoring commenced after the spill, examining immunity and hydrocarbon levels in the mussel, Mytilus edulis (Mollusca: Bivalvia), a commercially-harvested species which can accumulate contaminants. Comparisons of mussels from oiled and reference sites revealed significant modulations in cell-mediated immunity. Elevations in blood cell (haemocyte) numbers and decreases in superoxide generation and phagocytosis were identified in contaminated animals. The immune response of contaminated mussels gradually improved and generally showed no significant differences compared with clean mussels after 11 weeks. By then, total hydrocarbon content in contaminated mussels had declined by 70-90%, while polycyclic aromatic hydrocarbon content had decreased by over 90%. (author)

Using DNA barcoding to differentiate invasive Dreissena species (Mollusca, Bivalvia

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Jonathan Marescaux

2013-12-01

Full Text Available The zebra mussel (Dreissena polymorpha and the quagga mussel (Dreissena rostriformis bugensis are considered as the most competitive invaders in freshwaters of Europe and North America. Although shell characteristics exist to differentiate both species, phenotypic plasticity in the genus Dreissena does not always allow a clear identification. Therefore, the need to find an accurate identification method is essential. DNA barcoding has been proven to be an adequate procedure to discriminate species. The cytochrome c oxidase subunit 1 mitochondrial gene (COI is considered as the standard barcode for animals. We tested the use of this gene as an efficient DNA barcode and found that it allow rapid and accurate identification of adult Dreissena individuals.

Using DNA barcoding to differentiate invasive Dreissena species (Mollusca, Bivalvia).

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Marescaux, Jonathan; Van Doninck, Karine

2013-12-30

The zebra mussel (Dreissena polymorpha) and the quagga mussel (Dreissena rostriformis bugensis) are considered as the most competitive invaders in freshwaters of Europe and North America. Although shell characteristics exist to differentiate both species, phenotypic plasticity in the genus Dreissena does not always allow a clear identification. Therefore, the need to find an accurate identification method is essential. DNA barcoding has been proven to be an adequate procedure to discriminate species. The cytochrome c oxidase subunit I mitochondrial gene (COI) is considered as the standard barcode for animals. We tested the use of this gene as an efficient DNA barcode and found that it allow rapid and accurate identification of adult Dreissena individuals.

The sensorial structures of Spondylus americanus Hermann,1781 (Mollusca: Bivalvia, Spondylidae

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Marina Gomes Viana

2007-09-01

Full Text Available Adult animals of Spondylus americanus were analyzed and specialized sensorial structures, the sensorial papillae and the eyes, were characterized. The sensorial papillae were projections on the edge of the mantle in form of light brown fingers which had function of percepting stimulus coming from the medium. They were constituted by loose conjunctive tissues with longitudinal muscular fibers and externally covered by ciliated cubic epithelium, which presented high amount of melanocytes that gave the coloration of the papillae. The eyes were more complex, being on small stalks histologically similar to the papillae. They exhibited a circular formate and had a metallic blue color. Theses structures were constituted by a corneo epithelium, cornea, lens, retina, basal stalk, periocular band and optical nerve. The eyes were distributed asymmetrically to both valves related with the sedentarism of the species. Right valve presented a smaller number of eyes when compared to left one.Foram examinados exemplares adultos de Spondylus. americanus Hermann, 1781 e estruturas especializadas na percepção de estímulos foram caracterizadas: as papilas sensoriais e os ocelos. As papilas sensoriais são projeções do bordo manto em forma de dedos de cor castanha e com a função de perceber estímulos vindo do meio, são constituídas por tecido conjuntivo frouxo contendo fibras musculares longitudinais e revestidas externamente por epitélio cúbico ciliado, o qual apresenta grande quantidade de melanócitos, que dão a coloração das papilas. Os ocelos são mais complexos, estando sobre pequenos pedúnculos histologicamente semelhante às papilas, têm formato circular e possui cor azul metálica. Constituí-se por um epitélio córneo, córnea, lente, retina, pedúnculo basal, banda periocular e nervo óptico. Os ocelos distribuem-se assimetricamente por ambas as valvas, o que está relacionado com o sedentarismo da espécie. A valva direita apresenta menor número de ocelos quando comparada a esquerda.

Caloric variability of Corbicula fluminea (Mollusca, Bivalvia in Rosana Reservoir, Brazil

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Yara Moretto Bagatini

2007-01-01

Full Text Available The purpose of the present study was to investigate temporal and longitudinal variation of caloric density of Corbicula fluminea in Rosana Reservoir. Significant differences concerning the caloric density of C. fluminea were observed throughout the year at the three reservoir sites. The caloric density variation during the year was probably related to reproductive activity, which demanded higher allocation of energy in certain period. The food source used by this species might be an important factor in the caloric value temporal and spatial variation of C. fluminea in Rosana Reservoir.O objetivo deste estudo foi investigar a variação temporal e longitudinal da densidade calórica de C. fluminea no reservatório de Rosana. Diferenças significativas na densidade calórica de C. fluminea foram observadas ao longo do ano e nas três estações do reservatório. A variação na densidade calórica de C. fluminea, durante o ano, provavelmente foi relacionada à atividade reprodutiva, que exige uma maior alocação de energia em determinado período. O recurso alimentar utilizado por esta espécie pode ser um importante fator na variação temporal e espacial do valor calórico de C. fluminea no reservatório de Rosana.

Biocenosis de Bivalvia y Polyplacophora del intermareal rocoso en playa Tlacopanocha, Acapulco, Guerrero, México Polyplacophora and Bivalvia biocenosis at rocky intertidal Tlacopanocha beach, Acapulco, Guerrero, Mexico

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Lizeth Galeana-Rebolledo

2012-11-01

Full Text Available El Estado de Guerrero, México, tiene regiones marinas prioritarias para la conservación de su biodiversidad y la información acerca de la diversidad de moluscos es escasa, por lo que es necesario realizar inventarios de especies, estudios de ecología de poblaciones y comunidades. Este estudio se efectuó en el intermareal rocoso de la playa Tlacopanocha. Los objetivos fueron: determinar la riqueza, densidad y diversidad de especies; analizar la composición de especies y estructura de tallas. El área de muestreo fue de 10 m² y la unidad de muestreó fue de 1 m². Se identificaron 35 especies, de las cuales tres son nuevos registros para el intermareal rocoso de Guerrero: las familias mejor representadas en riqueza de especies fueron Ischnochitonidae y Arcidae, y en abundancia Chitonidae y Chamidae; la densidad fue de 31,60 ind m-2. Polyplacophora presentó 42,9% de especies dominantes y Bivalvia 19,0%. Chama corallina presentó la mayor talla en longitud y Chama sordida en ancho. La riqueza de especies de moluscos registrada se considera alta y corresponde a lo esperado para un sustrato rocoso en zona tropical. Polyplacophora presentó alta composición de especies, que podría ser resultado de la adaptación de los organismos a las condiciones dinámicas del intermareal rocoso. Los nuevos registros indican la importancia de los inventarios de especies y también del conocimiento de las poblaciones y comunidades de la fauna marina de Guerrero.The State of Guerrero, Mexico, has priority marine areas for conservation of its biodiversity, but information concerning diversity of mollusks is limited, so it is convenient to carry out species inventories, studies of populations and community ecology. This study was conducted in the intertidal rocky beach Tlacopanocha. The objectives were to determine richness, density and species diversity, analyze the species composition and size structure. The sampling area was 10 m² and the sampling unit was

First record of Stibarobdella moorei (Annelida, Hirudinea, Piscicolidae) a marine leech parasitizing Octopus bimaculatus (Mollusca: Octopodidae) from the Mexican Pacific coast

OpenAIRE

López-Peraza D. J.; Hernández-Rodríguez M.; Barón-Sevilla B.; Bückle-Ramírez L. F.; Grano-Maldonado M. I.

2017-01-01

The occurrence of the parasitic marine leech Stibarobdella moorei (Oka, 1910) (Hirudinea: Piscicolidae) along the northwest Mexican Pacific coast is described for the first time. This ectoparasite was collected from the skin of the Octopus bimaculatus (Verril, 1983) (Mollusca: Octopodidae). Stibarobdella loricata (Hardig, 1924) is synonymized with S. moorei as this species resembles other species of the genus based on tubercle patterns and the presence of papillae and a marginal fringe on the...

The mitochondrial genome of the sipunculid Phascolopsis gouldii supports its association with Annelida rather than Mollusca

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Boore, Jeffrey L.; Staton, Joseph

2001-09-01

We have determined the sequence of about half (7470 nts) of the mitochondrial genome of the sipunculid Phascolopsis gouldii, the first representative of this phylum to be so studied. All of the 19 identified genes are transcribed from the same DNA strand. The arrangement of these genes is remarkably similar to that of the oligochaete annelid Lumbricus terrestris. Comparison of both the inferred amino acid sequences and the gene arrangements of a variety of diverse metazoan taxa reveals that the phylum Sipuncula is more closely related to Annelida than to Mollusca. This requires reinterpretation of the homology of several embryological features and of patterns of animal body plan evolution.

The Upper Miocene of the Rostov Dome (Eastern Paratethys: Implication of the chronostratigraphy and bivalvia-based biostratigraphy

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Ruban Dmitry A.

2005-01-01

Full Text Available The Rostov Dome is located in the south of the Russian Platform. In the Late Miocene this area was embraced by the Eastern Paratethys. The implications of a recently developed Neogene chronostratigraphy to the studied area are discussed. The Sarmatian regional stage corresponds to the upper part of the Langhian, the entire Serravalian and the lower part of the Tortonian global stages; the Maeotian regional stage corresponds to the upper part of the Tortonian and the lowermost horizons of the Messinian global stages; the Pontian regional stage corresponds to most of the Messinian and the lowermost Zanclean global stages. A first Bivalvia-based bio-stratigraphic framework is proposed for the territory of the Rostov Dome. Five biozones were established within the Serravalian-Messinian: Tapes vitalianus, Cerastoderma fittoni-Cerastoderma subfittoni, Congeria panticapaea, Congeria amygdaloides navicula and Monodacna pseudocatillus-Prosodacna schirvanica.

Recrutamento larval e crescimento de teredinidae (mollusca-bivalvia em região entremarés de manguezais

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Sônia Godoy Bueno Carvalho Lopes

1997-01-01

environments, might be explained by the lower and more variable salinity gradient in estuaries. Larval settlement data revealed that the most abundant species was Nausitora fustieula (Jeffreys,1860, which settles on wood prefrerably in March, and has an initial growth rate of 1.86 mm/day. The other Teredinidae species Banida fimbriatula Moll & Roch, 1931, Bankia rochi Moll, 1931 and Neoteredo reynei (Bartsch, 1920, occurred in a very small number of specimens and therefore, their time of settlement and growth rates could not be determined.

A biomechanical model of rock drilling in the piddock Barnea candida (Bivalvia; Mollusca)

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Nederlof, R.; Muller, M.

2012-01-01

The bivalve Barnea candida (Pholadacea) makes its burrow in clay, soft rock and peat. Barnea has developed a number of adaptations to accommodate this lifestyle. Four muscles enable burrowing. These are situated around a dorsal pivot in such a way that the piddock is able to rotate the shells around

Systematic reviews on the Mesodesmatidae (Mollusca, Bivalvia) I. The Genus Monterosatus Beu, 1971

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Rooij-Schuiling, de L.A.

1977-01-01

In trying to identify a small Mesodesma from West Irian, New Guinea, much material in the collections of several museums was studied. As a guide for the identification I at first used the revision of the Mesodesmatidae by Lamy (1914), which is based exclusively on the collections of the Parisian

The Recent Pectinoidea of the New Zealand region (Mollusca: Bivalvia: Propeamussiidae, Pectinidae and Spondylidae)

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Dijkstra, H.H.; Marshall, B.A.

2008-01-01

The Recent Pectinoidea of the New Zealand region are reviewed. Eight new species are described from the New Zealand Exclusive Economic Zone: Parvamussium cancellorum, Cyclochlamys austrina, Cc. delli, Cc. irregularis, Cc. munida, Cc. pileolus, Cyclopecten fluctuosus, and Catillopecten tasmani. Nine

The Preliminary Study of Organochlorine Pesticide Residues on Sediments of Bivalvia Fishing Ground at Eastern Part of Coastal Semarang

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Adhi Suryono, Chrisna; Subagyo; Setyati, Wilis Ari; Sri Susilo, Endang; Rochaddi, Baskoro; Triaji Mahendrajaya, Robertus

2018-02-01

This paper presents the occurrence level of organochlorine contamination in marine sediments of Semarang coastal areas as a fishing ground of Bivalvia. Five compounds (Heptachlor, Aldrin, Endosulfan, Endrin and pp-DDT) of contaminant have been determined in the sediments surface of Semarang coastal waters. The samples were then analyzed by using gas chromatography and followed by using the method of Standard Method Examination. The result showed that the average concentration of organochlorine pesticides Heptachlor, Aldrin, Endosulfan, Endrin and pp-DDT were 25.5, bellow detected, 7.1, 37.2, 28.6 μ g/L, respectively. The high concentration of pesticide showed on Endrin (65,84 ppb), pp-DDT (29,53 μ g/L), and heptachlor (25,45 μ g/L). The low concentrations were detected on aldrin (bellow detected) and endosulfan (0,92 μ g/L). The concentration of organochlorine pesticides in these areas might contribute on four rivers which deposited the sediment in these coastal waters

On some Indo-Pacific boring endolithic Bivalvia species introduced into the Mediterranean Sea with their host – spread of Sphenia rueppelli A. Adams, 1850

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A. ZENETOS

2010-06-01

Full Text Available The study of the endolithic molluscs found on/in living alien Spondylusshells collected in the Gulf of Iskenderun (Turkey brought to light three more alien bivalvia species namely Petricola hemprichi, Gastrochaena cymbium and Sphenia rueppelli. The presence of Sphenia rueppellideserves attention as it constitutes the first record of this species as living in the Mediterranean Sea. The definitive establishment and spreading of these bivalves in the basin seems to be also attested by careful analysis of specimens sampled in other southern Turkish localities and previously retained in local private collections. The present records raise some questions on the vector of arrival of the species in the Mediterranean Sea that could be strictly connected with their hosts.

Quitones (Mollusca: Polyplacophora de El Salvador, América Central

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Cedar I García-Ríos

2007-03-01

Full Text Available En El Salvador se habían registrado los poliplacóforos Chaetopleura lurida (Sowerby, 1832; Ischnochiton guatemalensis (Thiele, 1910; Ceratozona angusta (Thiele, 1909; Chiton stokesii (Broderip, 1832 y Acantochitona exquisita (Pilsbry, 1893. Recolectamos quitones en aguas someras de El Salvador en julio del 2002, agragando a la lista a Lepidochitona beanii (Carpenter, 1857; Ischnochiton dispar (Sowerby, 1832; Stenoplax limaciformis (Sowerby, 1832; Callistochiton expressus (Carpenter, 1865; Acanthochitona arragonites (Carpenter, 1867; Acanthochitona ferreirai (Lyons, 1988 y Acanthochitona hirudiniformis (Sowerby, 1832. Ampliamos la distribución documentada de I. dispar hacia el norte y describimos brevemente una especie innominada de Lepidochitona.Chitons (Mollusca: Polyplacophora from El Salvador, Central America. Collections of 11 species of shallow water Polyplacophora from El Salvador were made in July 2002. Previously only five species had been documented in El Salvador: Chaetopleura lurida (Sowerby, 1832; Ischnochiton guatemalensis (Thiele, 1910; Ceratozona angusta (Thiele, 1909; Chiton stokesii (Broderip, 1832 and Acantochitona exquisita (Pilsbry, 1893. Of these, I. guatemalensis and A. exquisita were not collected in this census. Seven other species are reported here for El Salvador for the first time: Lepidochitona beanii (Carpenter, 1857; Ischnochiton dispar (Sowerby, 1832; Stenoplax limaciformis (Sowerby, 1832; Callistochiton expressus (Carpenter, 1865; Acanthochitona arragonites (Carpenter, 1867; A. ferreirai (Lyons, 1988 and A. hirudiniformis (Sowerby, 1832. The known geographic distribution of I. dispar is extended to the north. An un-named species of Lepidochitona is briefly described. Rev. Biol. Trop. 55 (1: 171-176. Epub 2007 March. 31.

Cell proliferation and apoptosis in gill filaments of the lucinid Codakia orbiculata (Montagu, 1808) (Mollusca: Bivalvia) during bacterial decolonization and recolonization.

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Elisabeth, Nathalie H; Gustave, Sylvie D D; Gros, Olivier

2012-08-01

The shallow-water bivalve Codakia orbiculata which harbors gill-endosymbiotic sulfur-oxidizing γ-proteobacteria can lose and acquire its endosymbionts throughout its life. Long-term starvation and recolonization experiments led to changes in the organization of cells in the lateral zone of gill filaments. This plasticity is linked to the presence or absence of gill-endosymbionts. Herein, we propose that this reorganization can be explained by three hypotheses: (a) a variation in the number of bacteriocytes and granule cells due to proliferation or apoptosis processes, (b) a variation of the volume of these two cell types without modification in the number, and (c) a combination of both number and cell volume variation. To test these hypotheses, we analyzed cell reorganization in terms of proliferation and apoptosis in adults submitted to starvation and returned to the field using catalyzed reporter deposition fluorescence in situ hybridization, immunohistochemistry, and structural analyses. We observed that cell and tissue reorganization in gills filaments is due to a variation in cell relative abundance that maybe associated with a variation in cell apparent volume and depends on the environment. In fact, bacteriocytes mostly multiply in freshly collected and newly recolonized individuals, and excess bacteriocytes are eliminated in later recolonization stages. We highlight that host tissue regeneration in gill filaments of this symbiotic bivalve can occur by both replication of existing cells and division of undifferentiated cells localized in tissular bridges, which might be a tissue-specific multipotent stem cell zone. Copyright © 2012 Wiley Periodicals, Inc.

Comparative studies on the morphometry and physiology of European populations of the lagoon specialist Cerastoderma glaucum (Bivalvia

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Katarzyna Tarnowska

2009-09-01

Full Text Available Seasonal changes in the morphometric and physiological parameters of the cockle Cerastoderma glaucum (Bivalvia from the Baltic Sea (GD, the North Sea (LV, and the Mediterranean Sea (BL were investigated. The cockles from GD were much smaller than those from other populations due to osmotic stress. The female to male ratios did not differ significantly from 1:1. The northern populations (GD, LV had a monocyclic reproductive pattern, whereas the southern population (BL seemed to reproduce throughout the year. Seasonal changes in the contents of biochemical components appeared to be correlated with changes in trophic conditions and the reproductive cycle. Protein content was the highest in spring for all the populations. The highest lipid contents and lowest carbohydrate contents were noted in GD and BL in spring, while no marked differences were noted among seasons in LV (probably because the data from both sexes were pooled. Respiration rates in GD were the highest among the populations, which could have been due to osmotic stress. High metabolic rates expressed by high respiration rates in GD and LV in spring and autumn could have resulted from gamete development (in spring and phytoplankton blooms (in spring and autumn.

Relación entre las capturas de Megapitaria squalida (Bivalvia: Veneridae y la temperatura superficial del mar en la Bahía de la Paz, Baja California Sur, México

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Mariana Vázquez Hurtado

2011-03-01

Full Text Available La almeja chocolate Megapitaria squalida es un recurso pesquero con creciente importancia en el noroeste de México al registrarse un incremento en los volúmenes de captura. Sin embargo, esta pesquería ha observado variaciones importantes en las capturas que podrían estar relacionadas con factores ambientales. Se obtuvieron datos mensuales de producción de M. squalida durante 2002- 2005 y se estimaron series de tiempo de temperatura superficial del mar en la Bahía de La Paz B.C.S. a partir de imágenes mensuales derivadas del sensor MODIS-Aqua. Los resultados indican una relación positiva significativa entre la temperatura superficial del mar y los volúmenes de captura, razón por la cual nuestro trabajo tiene como objetivo estudiar las relaciones entre capturas de Megapitaria squalida (Bivalvia: Veneridae y la temperatura superficial del mar en La Bahía de la Paz, Baja California Sur, México.Megapitaria squalida (Bivalvia: Veneridae fishery landings and temperature relationship in Bahía de la Paz, México. The clam Megapitaria squalida is a fishing resource with increasing importance in Northwestern Mexico. Nevertheless, this fishery has shown important variations that could be related to environmental factors. To assess this, monthly landings of M. squalida were analyzed during 2002-2005 for Bahía de La Paz, B.C.S., and were related with monthly time series of sea surface temperature, derived from MODIS-Aqua Sensor. The results showed a positive and significant relationship between sea surface temperature and clam landings. The likely impact of anomalous conditions of sea temperature on this resource is discussed. Rev. Biol. Trop. 59 (1: 151-157. Epub 2011 March 01.

Seasonal variation in biomarker responses of Donax trunculus from the Gulf of Annaba (Algeria): Implication of metal accumulation in sediments

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Amira, Akila; Merad, Isma; Almeida, C. Marisa R.; Guimarães, Laura; Soltani, Nourredine

2018-05-01

The aim of the present study was to test biomarker responses in an edible mollusk, Donax trunculus L. (Mollusca, Bivalvia) associated with environmental pollution in the Gulf of Annaba (northeastern Algeria). The biomarkers selected were glutathione S-transferase (GST), acetylcholinesterase (AChE) and metallothioneins (MTs). Samples were collected seasonally (September 2014, and January, April and July 2015) from two sites located over the Gulf of Annaba: El Battah and Sidi Salem. The results obtained reveal that autumn and winter were the two seasons that show an increase in GST activity, an inhibition of AChE activity and a high rate of MT. In addition, a decrease in AChE activity, an increase in both GST activity and MT levels in D. Trunculus collected from Sidi Salem in comparison with those of El Battah were observed. The biomarker responses at the Sidi Salem site reflect the presence of certain pro-oxidative compounds such as metals (Cd, Cu, Pb, Zn, Mn and Fe) determined in sediments in winter (January) 2015. Moreover, metal concentrations, except Fe, were higher at Sidi Salem than at El Battah. Overall, the Gulf of Annaba remains contaminated by heavy metal. However, this metallic contamination is relatively low and the risks for local population via this edible species were also low.

Mollusca from a species-rich deep-water Leptometra community in the Alboran Sea

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Serge Gofas

2014-12-01

Full Text Available An exceptional species richness for Mollusca was found on Avempace bank (349-365 m, Djibouti group, Alboran Sea, where the most abundant species was the crinoid Leptometra phalangium. A sample of sediment sieved on a 0.5-mm mesh yielded 156 species of molluscs (83 live-taken, 1772 specimens with a high Shannon-Wiener diversity index (H’(log2=3.60. The dominant mollusc was Limopsis aurita and the six most common species accounted for 77% of the specimens. On the other hand, 42 species were represented by only one or two specimens. Two species are described as new, three more are first findings in the Mediterranean and two are first findings in Iberian waters. One-third of the species have not been reported from the neighbouring, well-explored Alboran Island platform. There is a considerable balance between the trophic groups, denoting a stable and structured community. Most of the species have an extensive Atlantic range, and most have a planktonic larval stage. Therefore, it can be hypothesized that the fauna benefits from a diverse influx of larvae carried in by the more superficial incoming Atlantic current. Because of its exceptional richness, this type of bathyal community with Leptometra and Limopsis should be considered a high priority for habitat conservation in the Mediterranean deep sea.

Annotated type catalogue of the Orthalicoidea (Mollusca, Gastropoda) in the Museum für Naturkunde, Berlin.

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Breure, Abraham S H

2013-01-01

The type status is described of 96 taxa classified within the superfamily Orthalicoidea and present in the Mollusca collection of the Museum für Naturkunde der Humboldt-Universität zu Berlin. Lectotypes are designated for the following taxa: Orthalicus elegans Rolle, 1895; Bulimus maranhonensis Albers, 1854; Orthalicus nobilis Rolle, 1895; Orthalichus tricinctus Martens, 1893. Orthalicus sphinx tresmariae is introduced as new name for Zebra sphinx turrita Strebel, 1909, not Zebra quagga turrita Strebel, 1909. The following synonyms are established: Zebra crosseifischeri Strebel, 1909 = Orthalicus princeps fischeri Martens, 1893; Orthalicus isabellinus Martens, 1873 = Orthalicus bensoni (Reeve, 1849); Zebra zoniferus naesiotes Strebel, 1909 = Orthalicus undatus (Bruguière, 1789); Porphyrobaphe (Myiorthalicus) dennisoni pallida Strebel, 1909 = Hemibulimus dennisoni (Reeve, 1848); Zebra delphinus pumilio Strebel, 1909 = Orthalicus delphinus (Strebel, 1909); Orthalicus (Laeorthalicus) reginaeformis Strebel, 1909 = Corona perversa (Swainson, 1821); Bulimus (Eurytus) corticosus Sowerby III, 1895 = Plekocheilus (Eurytus) stuebeli Martens, 1885. The taxon Bulimus (Eudioptus) psidii Martens, 1877 is now placed within the family Sagdidae, tentatively in the genus Platysuccinea. Appendices are included with an index to all the types of Orthalicoidea extant (including those listed by Köhler 2007) and a partial list of letters present in the correspondence archives.

Factors driving changes in freshwater mussel (Bivalvia, Unionida) diversity and distribution in Peninsular Malaysia.

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Zieritz, Alexandra; Lopes-Lima, Manuel; Bogan, Arthur E; Sousa, Ronaldo; Walton, Samuel; Rahim, Khairul Adha A; Wilson, John-James; Ng, Pei-Yin; Froufe, Elsa; McGowan, Suzanne

2016-11-15

Freshwater mussels (Bivalvia, Unionida) fulfil important ecosystem functions and are one of the most threatened freshwater taxa globally. Knowledge of freshwater mussel diversity, distribution and ecology in Peninsular Malaysia is extremely poor, and the conservation status of half of the species presumed to occur in the region has yet to be assessed. We conducted the first comprehensive assessment of Peninsular Malaysia's freshwater mussels based on species presence/absence and environmental data collected from 155 sites spanning all major river catchments and diverse habitat types. Through an integrative morphological-molecular approach we recognised nine native and one widespread non-native species, i.e. Sinanodonta woodiana. Two species, i.e. Pilsbryoconcha compressa and Pseudodon cambodjensis, had not been previously recorded from Malaysia, which is likely a result of morphological misidentifications of historical records. Due to their restriction to single river catchments and declining distributions, Hyriopsis bialata, possibly endemic to Peninsular Malaysia, Ensidens ingallsianus, possibly already extinct in the peninsula, and Rectidens sumatrensis, particularly require conservation attention. Equally, the Pahang, the Perak and the north-western river catchments are of particular conservation value due to the presence of a globally unique freshwater mussel fauna. Statistical relationships of 15 water quality parameters and mussel presence/absence identified acidification and nutrient pollution (eutrophication) as the most important anthropogenic factors threatening freshwater mussel diversity in Peninsular Malaysia. These factors can be linked to atmospheric pollution, deforestation, oil-palm plantations and a lack of functioning waste water treatment, and could be mitigated by establishing riparian buffers and improving waste water treatment for rivers running through agricultural and residential land. Copyright © 2016 Elsevier B.V. All rights reserved.

The Pleurobemini (Bivalvia: Unionida) revisited: Molecular species delineation using a mitochondrial DNA gene reveals multiple conspecifics and undescribed species

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Inoue, Kentaro; Hayes, David M.; Harris, John L.; Johnson, Nathan A.; Morrison, Cheryl L.; Eackles, Michael S.; King, Tim; Jones, Jess W.; Hallerman, Eric M.; Christian, Alan D.; Randklev, Charles R.

2018-01-01

The Pleurobemini (Bivalvia: Unionida) represent approximately one-third of freshwater mussel diversity in North America. Species identification within this group is challenging due to morphological convergence and phenotypic plasticity. Accurate species identification, including characterization of currently unrecognized taxa, is required to develop effective conservation strategies because many species in the group are imperiled. We examined 573 cox1 sequences from 110 currently recognized species (including 13 Fusconaia and 21 Pleurobema species) to understand phylogenetic relationships among pleurobemine species (mainly Fusconaia and Pleurobema) and to delineate species boundaries. The results of phylogenetic analyses showed no geographic structure within widespread species and illustrated a close relationship between Elliptio lanceolata and Parvaspina collina. Constraint tests supported monophyly of the genera Fusconaia and Pleurobema, including the subgenus P. (Sintoxia). Furthermore, results revealed multiple conspecifics, including P. hanleyianum and P. troschelianum, P. chattanoogaense and P. decisum, P. clava and P. oviforme, P. rubrum and P. sintoxia, F. askewi and F. lananensis, and F. cerina and F. flava. Species delimitation analyses identified three currently unrecognized taxa (two in Fusconaia and one in Pleurobema). Further investigation using additional genetic markers and other lines of evidence (e.g., morphology, life history, ecology) are necessary before any taxonomic changes are formalized.

Ross Sea Mollusca from the Latitudinal Gradient Program: R/V Italica 2004 Rauschert dredge samples

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Claudio Ghiglione

2013-10-01

Full Text Available Information regarding the molluscs in this dataset is based on the Rauschert dredge samples collected during the Latitudinal Gradient Program (LGP on board the R/V “Italica” in the Ross Sea (Antarctica in the austral summer 2004. A total of 18 epibenthic dredge deployments/samplings have been performed at four different locations at depths ranging from 84 to 515m by using a Rauschert dredge with a mesh size of 500µm. In total 8,359 specimens have been collected belonging to a total of 161 species. Considering this dataset in terms of occurrences, it corresponds to 505 discrete distributional records (incidence data. Of these, in order of abundance, 5,965 specimens were Gastropoda (accounting for 113 species, 1,323 were Bivalvia (accounting for 36 species, 949 were Aplacophora (accounting for 7 species, 74 specimens were Scaphopoda (3 species, 38 were Monoplacophora (1 species and, finally, 10 specimens were Polyplacophora (1 species. This data set represents the first large-scale survey of benthic micro-molluscs for the area and provides important information about the distribution of several species, which have been seldom or never recorded before in the Ross Sea. All vouchers are permanently stored at the Italian National Antarctic Museum (MNA, Section of Genoa, enabling future comparison and crosschecking. This material is also currently under study, from a molecular point of view, by the barcoding project “BAMBi” (PNRA 2010/A1.10.

First record of Stibarobdella moorei (Annelida, Hirudinea, Piscicolidae a marine leech parasitizing Octopus bimaculatus (Mollusca: Octopodidae from the Mexican Pacific coast

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López-Peraza D. J.

2017-12-01

Full Text Available The occurrence of the parasitic marine leech Stibarobdella moorei (Oka, 1910 (Hirudinea: Piscicolidae along the northwest Mexican Pacific coast is described for the first time. This ectoparasite was collected from the skin of the Octopus bimaculatus (Verril, 1983 (Mollusca: Octopodidae. Stibarobdella loricata (Hardig, 1924 is synonymized with S. moorei as this species resembles other species of the genus based on tubercle patterns and the presence of papillae and a marginal fringe on the oral sucker. The present finding throws new light on the biodiversity and host preference of the ectoparasite and suggests a successful migration to unusual host. The coast of the Pacific Ocean, particularly in the Bay of Los Angeles, Baja California, Mexico is a new geographical distribution area for S. moorei, and O. bimaculatus is a new host reported for this leech. The morphology of this ectoparasite is briefly described.

Seasonal variation in larval density of Limnoperna fortunei (Bivalvia, Mytilidae in the Iguaçu and Paraná rivers, in the region of Foz do Iguaçu, Paraná, Southern Brazil

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Débora Pestana

2008-06-01

Full Text Available The larval density of the invasive mussel Limnoperna fortunei (Bivalvia, Mytilidae was monitored from January 2005 to February 2006 at two points along the Paraná and the Iguaçu Rivers, near Foz do Iguaçu, PR, Brazil. The results indicated two density peaks in the Paraná River: a lower peak between March and June and a higher peak in October. In the Iguaçu River, the values were much lower, yet they also showed a peak between September and October. A reduction in the reproductive activity was observed in both the rivers between July and August. The average larval density at the collection point in the Paraná reached 948.5 larvae/m³, with a peak of 2,999.5 larvae/m³ in October. The present study represented the first quantification of the larval density of L. fortunei in the lower reaches of the Iguaçu River, downstream of the Iguaçu falls.A densidade larval do molusco invasor Limnoperna fortunei (Bivalvia, Mytilidae foi monitorada entre janeiro de 2005 e fevereiro de 2006 em dois pontos dos rios Paraná e Iguaçu, na região de Foz do Iguaçu, PR. Os resultados registraram dois picos de densidade no rio Paraná: entre março e junho e um maior em outubro. No rio Iguaçu, os valores foram muito inferiores, mas também com um pico entre setembro-outubro. Em ambos os rios foi verificada uma pausa reprodutiva entre os meses de julho-agosto. A densidade média de larvas de L. fortunei no ponto amostrado no rio Paraná chegou a 948.5 larvas/m³, com pico de 2.999,5 larvas/m³ em outubro. O presente estudo representa a primeira quantificação da densidade larval de L. fortunei no rio Iguaçu, a jusante das Cataratas do Iguaçu.

Biochemical profile of Achatina fulica (Mollusca: Gastropoda) after infection by different parasitic loads of Angiostrongylus cantonensis (Nematoda, Metastrongylidae).

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Tunholi-Alves, Vinícius Menezes; Tunholi, Victor Menezes; Amaral, Ludimila Santos; Mota, Esther Maria; Maldonado Júnior, Arnaldo; Pinheiro, Jairo; Garcia, Juberlan

2015-01-01

The effect of experimental infection by different parasitic loads of Angiostrongylus cantonensis (Nematode, Metastrongylidae) on the activities of the aminotransferases and concentration of total proteins, uric acid and urea in the hemolymph of Achatina fulica (Mollusca, Gastropoda) were investigated. There was a significant decrease in the concentration of total proteins in the exposed snails to 5000 or more larvae. This change was accompanied by an increase in the concentrations of urea and uric acid in the hemolymph, suggesting a higher rate of deamination of the amino acids. Besides this, variations in the activities of the aminotransferases were also observed, with the highest values recorded in the groups exposed to greater parasite load. These results suggest an increase in the use of total proteins, since there was increased formation of nitrogenous catabolites, in conformity with an increase in the aminotransferase activities. Infection was verified by the fact that L3 larvae recovered from the snails was proportion to the exposure dose of L1 larvae. Histopathological results also indicated presence of an inflammatory cell infiltrate, favoring an increase of both transaminases. Copyright © 2014 Elsevier Inc. All rights reserved.

In situ distribution and characterization of the organic content of the oyster shell Crassostrea gigas (Mollusca, Bivalvia).

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Dauphin, Yannicke; Ball, Alexander D; Castillo-Michel, Hiram; Chevallard, Corinne; Cuif, Jean-Pierre; Farre, Bastien; Pouvreau, Stéphane; Salomé, Murielle

2013-01-01

Cultivation of commercial oysters is now facing the possible influence of global change in sea water composition, commonly referred to as "ocean acidification". In order to test the potential consequence of the predicted environmental changes, a cultivation experiment was carried out. The left and right valves of the oyster shell Crassostrea gigas differ in their structure; moreover, lenses of non compact layers are irregular. The shell layers of juvenile C. gigas are studied using a variety of highly spatially resolved techniques to establish their composition and structure. Our results confirm the presence of three different calcitic structural types. The role of the lenses of chalky layers is not yet deciplered. Despite a common mineralogy, the elemental composition of the layers differs. The sulphur aminoacids and sulphated polysaccharide contents of the intracrystalline and intercrystalline matrices differ, as well as those of the structural types. The possible different sensitivity of these structures to environmental changes is still unknown. Copyright © 2012 Elsevier Ltd. All rights reserved.

Microsatellite loci for dreissenid mussels (Mollusca: Bivalvia: Dreissenidae) and relatives: markers for assessing exotic and native populations.

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Feldheim, Kevin A; Brown, Joshua E; Murphy, Douglas J; Stepien, Carol A

2011-07-01

We developed and tested 14 new polymorphic microsatellite loci for dreissenid mussels, including the two species that have invaded many freshwater habitats in Eurasia and North America, where they cause serious industrial fouling damage and ecological alterations. These new loci will aid our understanding of their genetic patterns in invasive populations as well as throughout their native Ponto-Caspian distributions. Eight new loci for the zebra mussel Dreissena polymorpha polymorpha and six for the quagga mussel D. rostriformis bugensis were compared with new results from six previously published loci to generate a robust molecular toolkit for dreissenid mussels and their relatives. Taxa tested include D. p. polymorpha, D. r. bugensis, D. r. grimmi, D. presbensis, the 'living fossil'Congeria kusceri, and the dark false mussel Mytilopsis leucophaeata (the latter also is invasive). Overall, most of the 24 zebra mussel (N = 583) and 13 quagga mussel (N = 269) population samples conformed to Hardy-Weinberg equilibrium expectations for the new loci following sequential Bonferroni correction. The 11 loci (eight new, three previously published) evaluated for D. p. polymorpha averaged 35.1 alleles and 0.72 mean observed heterozygosity per locus, and 25.3 and 0.75 for the nine loci (six new, three previously published) developed for D. r. bugensis. All but three of these loci successfully amplified the other species of Dreissena, and all but one also amplified Congeria and Mytilopsis. All species and populations tested were significantly divergent using the microsatellite data, with neighbour-joining trees reflecting their evolutionary relationships; our results reveal broad utility for resolving their biogeographic, evolutionary, population and ecological patterns. © 2011 Blackwell Publishing Ltd.

The effects of mercury exposure on the surface morphology of gill filaments in Perna perna (Mollusca: Bivalvia)

CSIR Research Space (South Africa)

Gregory, MA

1999-01-01

Full Text Available each animal were analysed for mercury using an atomic absorption spectrometer. Mercury concentration increased from 0.13 (pre-immersion) to 87 mu g/g after day 24. Surface morphology remained normal for all animals in tank 2 and for those exposed to Hg...

Biomonitoring study of an estuarine coastal ecosystem, the Sacca di Goro lagoon, using Ruditapes philippinarum (Mollusca: Bivalvia)

International Nuclear Information System (INIS)

Sacchi, Angela; Mouneyrac, Catherine; Bolognesi, Claudia; Sciutto, Andrea; Roggieri, Paola; Fusi, Marco; Beone, Gian Maria; Capri, Ettore

2013-01-01

Coastal lagoons are constantly subjected to releases of chemical pollutants, and so organisms may be exposed to such toxicants. This study investigated through a multivariate approach the physiological status of bivalve Ruditapes philippinarum, farmed in Sacca di Goro lagoon. Biomarkers at different levels of biological organization (catalase, superoxide dismutase, genotoxicity, reburrowing behavior) were evaluated at three sites exposed to different environmental conditions. A seasonal trend was observed, and micronucleus frequency was significantly lowest at the relatively pristine reference site. Enzymatic activity toward oxyradicals be quite efficient since variations in responsiveness were not consistent. However, behavioral impairment was observed in reburrowing rates. Sediment concentrations showed low PAH levels and high natural levels of trace metals Cr and Ni. DistLM statistical analysis revealed a non-significant relationship between selected biomarkers and xenobiotics. Therefore other potentially toxic compounds in admixture at low doses may be involved in driving differing spatial distribution of physiological impairment. -- Highlights: ► Health status assessment of bivalve Ruditapes philippinarum, from lagoon of Sacca di Goro. ► Multiparametric approach (chemical analysis, biochemical and behavioral biomarkers). ► Impairments of burrowing kinetics in the contaminated site. ► Micronucleus genotoxicity test to detect effects of contaminants complex mixture. ► Multiple stress of chemicals in estuarine costal ecosystem. -- The bivalve Ruditapes philippinarum as a bioindicator in monitoring pollution of estuaries

Anatomy and systematics of Anodontites Elongatus (Swainson from Amazon and Parana Basins, Brazil (Mollusca, Bivalvia, Unionoida, Mycetopodidae

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Luiz Ricardo L Simone

1997-12-01

Full Text Available The anatomy of Anodontiies elongatus (Swainson, 1823, a rare species restricted to the Amazon and Parana Basins, is described by first time, showing a group of conchological and anatomical characters exclusive of this species that may be analyzed to identify it. Diagnosis of A. elongatus: shell long antero-posteriorly, umbones prominent, periostracum opaque and smooth, two posterior radial striae; middle fold of mantle edge veiy tall; gill long antero-posteriorly and short dorso-ventrally, extending about a half of it total length beyond visceral mass; palps proportionally small, several furrows in its outer surface; stomach without esophageal transversal ridjp, dorsal hood and gastric shield poorly developed, major typhlosole entering in ddd , posterior pouch of sa³ very-long; style sac reduced, without crystalline style; distal region of intestine and rectum with a well developed typhlosole, "T" in section, other intestinal regions without folds; gonad gonochoristic.

Cytogenetic characterisation of the razor shells Ensis directus (Conrad, 1843) and E. minor (Chenu, 1843) (Mollusca: Bivalvia)

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González-Tizón, Ana M.; Rojo, Verónica; Vierna, Joaquín; Jensen, K. Thomas; Egea, Emilie; Martínez-Lage, Andrés

2013-03-01

The European razor shell Ensis minor (Chenu 1843) and the American E. directus (Conrad 1843) have a diploid chromosome number of 38 and remarkable differences in their karyotypes: E. minor has four metacentric, one metacentric-submetacentric, five submetacentric, one subtelocentric and eight telocentric chromosome pairs, whereas E. directus has three metacentric, two metacentric-submetacentric, six submetacentric, six subtelocentric and two telocentric pairs. Fluorescent in situ hybridisation (FISH) using a major ribosomal DNA probe located the major ribosomal genes on one submetacentric chromosome pair in both species; FISH with a 5S ribosomal DNA (5S rDNA) probe rendered one chromosomal (weak) signal for E. minor and no signal for E. directus, supporting a more dispersed organisation of 5S rDNA compared to the major ribosomal genes. The vertebrate telomeric sequence (TTAGGG) n was located on both ends of each chromosome, and no interstitial signals were detected. In this work, a comparative karyological analysis was also performed between the four Ensis species analysed revealing that the three European species studied so far, namely E. minor, E. siliqua (Linné 1758) and E. magnus Schumacher 1817 show more similarities among them than compared to the American species E. directus. In addition, clear karyotype differences were found between the morphologically similar species E. minor and E. siliqua.

The Effects of Mercury Exposure on the Surface Morphology of Gill Filaments in Perna perna (Mollusca: Bivalvia)

International Nuclear Information System (INIS)

Gregory, M.A.; George, R.C.; Marshall, D.J.; Anandraj, A.; McClurg, T.P.

1999-01-01

This study investigated the possibility that changes in the surface morphology of mussel (Perna perna) gill filaments may be used to indicate the relative toxicity of pollutants in the marine environment. Healthy, adult P. perna were collected and immersed in 2 free-flow tanks. Mercury was added to seawater as it entered tank 1 to achieve a constant level of 50 μg/l -1 over 24 days. Uncontaminated seawater was circulated over the mussels in tank 2 (control) for the same period. A 25 mm 2 area of gill filament was removed from each of the 5 specimens before and after 24 days immersion in tank 2, and after immersion for 1, 2, 4, 8, 16 and 24 days in tank 1. These were examined using a scanning electron microscope. The remaining soft tissues from each animal were analysed for mercury using an atomic absorption spectrometer. Mercury concentration increased from 0.13 (pre-immersion) to 87 μg/g after day 24. Surface morphology remained normal for all animals in tank 2 and for those exposed to Hg for up to 8 days. However, from 16 to 24 days exposure there was a gradual increase in the diameters of microvilli, a depletion of abfrontal cilia, an increase in abnormal, perhaps necrotic cells and an unusual increase in the number of cilia on the lateral surfaces. These results confirm that P. perna is an efficient bio-accumulator and suggest that their gill pathomorphology may be a useful indicator of toxicity

Molecular discrimination of Perna (Mollusca: Bivalvia) species using the polymerase chain reaction and species-specific mitochondrial primers

DEFF Research Database (Denmark)

Blair, D.; Waycott, M.; Byrne, L.

2006-01-01

This work was prompted by the need to be able to identify the invasive mussel species, Perna viridis, in tropical Australian seas using techniques that do not rely solely on morphology. DNA-based molecular methods utilizing a polymerase chain reaction (PCR) approach were developed to distinguish...

Population dynamics of freshwater oyster Etheria elliptica (Bivalvia: Etheriidae in the Pendjari River (Benin-Western Africa

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Akélé G.D.

2015-01-01

Full Text Available Etheria elliptica (Bivalvia: Etheriidae is the only freshwater oyster occurring in Africa. The current study provides the first data on the population structure, growth, age, mortality and exploitation status of this species in the Pendjari River. E. elliptica length-frequency data were collected monthly from January to December 2009 and analyzed with FiSAT software. Population parameters including the asymptotic length (L∞ and growth coefficient (K were assessed to evaluate the stock status. The recruitment pattern was modeled with a FiSAT routine. The asymptotic length (L∞ was 14.75 cm, while the growth coefficient (K was 0.38 year-1. The growth performance index (ø′ reached 1.92. Specimens of Etheria elliptica reached a mean size of 4.66 cm and 6.41 cm at the end of one year and 1.5 years, respectively. We estimated total mortality (Z, natural mortality (M and fishing mortality (F to be 2.90 year-1, 1.16 year-1 and 1.74 year-1, respectively. The recruitment pattern was continuous over the year with one major peak event during the rainy season (July. The exploitation rate (E = 0.60 revealed that the freshwater oyster was probably facing overexploitation due to lack of a minimum limit size and also due to an increase in the harvesting effort. Therefore, efficient management methods were urgently required to conserve the species. The return of empty shells into the water to increase the recruitment surface, rotation planning among harvesting sites and the imposition of a minimum limit size were recommendations made in order to ensure the sustainable exploitation of wild stocks.

Diversidad y microestructura de quitones (Mollusca: Polyplacophora del Caribe de Costa Rica

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Cedar I García-Ríos

2011-03-01

Full Text Available Los poliplacóforos asociados a los arrecifes de coral en la costa caribeña de Costa Rica han sido poco estudiados. El examen del cascajo de coral acumulado en el sublitoral somero, en cuatro estaciones de colección, localizadas en la Provincia de Limón reveló una diversidad de quitones mayor a la documentada. Anteriormente se habían registrado ocho especies para el Caribe costaricense: Ischnochiton erythronotus (C.B. Adams, 1845; Ischnoplax pectinata (Sowerby 1840; Stenoplax boogii (Haddon, 1886; S. purpurascens (C.B. Adams, 1845; Acanthopleura granulata (Gmelin, 1791; Chiton marmoratus Gmelin, 1791; C. tuberculatus Linnaeus, 1758; Acanthochitona rhodea (Pilsbry, 1893. Otras cinco se registran aquí por primera vez: Callistochiton portobelensis Ferreira 1976; Ischnochiton kaasi Ferreira 1987; I. pseudovirgatus Kaas 1972; Acanthochitona balesae Abbott 1954; Cryptoconchus floridanus (Dall 1889.Diversity and microstructure of quitons (Mollusca: Polyplacophora from the Caribbean of Costa Rica. The polyplacophorans of the coral reef on the Caribbean coast of Costa Rica have been insufficiently studied. The examination of coral rubble accumulated in the shallow sublitoral waters on four collection stations in Provincia Limón revealed a higher diversity of chitons than was documented. From the country eight species were previously known: Ischnochiton erythronotus (C.B. Adams 1845; Ischnoplax pectinata (Sowerby 1840; Stenoplax boogii (Haddon 1886; S. purpurascens (C.B. Adams 1845; Acanthopleura granulate (Gmelin 1791; Chiton marmoratus Gmelin 1791; C. tuberculatus Linnaeus 1758 and Acanthochitona rhodea (Pilsbry 1893. This study added five more species that are reported here for the first time: Callistochiton portobelensis Ferreira 1976; Ischnochiton kaasi Ferreira 1987; I. pseudovirgatus Kaas 1972; Acanthochitona balesae Abbott 1954 and Cryptoconchus floridanus (Dall 1889. Rev. Biol. Trop. 59 (1: 129-136. Epub 2011 March 01.

The Complete Sequence of the Mitochondrial Genome of the Chamberednautilus (Mollusca: Cephalopoda)

Energy Technology Data Exchange (ETDEWEB)

Boore, Jeffrey L.

2005-12-01

Background: Mitochondria contain small genomes that arephysically separate from those of nuclei. Their comparison serves as amodel system for understanding the processes of genome evolution.Although complete mitochondrial genome sequences have been reported formore than 600 animals, the taxonomic sampling is highly biased towardvertebrates and arthropods, leaving much of the diversity yetuncharacterized. Results: The mitochondrial genome of a cephalopodmollusk, the Chambered Nautilus, is 16,258 nts in length and 59.5 percentA+T, both values that are typical of animal mitochondrial genomes. Itcontains the 37 genes that are typical for animal mtDNAs, with 15 on oneDNA strand and 22 on the other. The arrangement of these genes can bederived from that of the distantly related Katharina tunicata (Mollusca:Polyplacophora) by a switch in position of two large blocks of genes andtranspositions of four tRNA genes. There is strong skew in thedistribution of nucleotides between the two strands. There are an unusualnumber of non-coding regions and their function, if any, is not known;however, several of these demark abrupt shifts in nucleotide skew,suggesting that they may play roles in transcription and/or replication.One of the non-coding regions contains multiple repeats of a tRNA-likesequence. Some of the tRNA genes appear to overlap on the same strand,but this could be resolved if the polycistron were cleaved at thebeginning of the downstream gene, followed by polyadenylation of theproduct of the upstream gene to form a fully paired structure.Conclusions: Nautilus sp. mtDNA contains an expected gene content thathas experienced few rearrangements since the evolutionary split betweencephalopods and polyplacophorans. It contains an unusual number ofnon-coding regions, especially considering that these otherwise often aregenerated by the same processes that produce gene rearrangements. Thisappears to be yet another case where polyadenylation of mitochondrialtRNAs restores

The Pleurobemini (Bivalvia: Unionida) revisited: Molecular species delineation using a mitochondrial DNA gene reveals multiple conspecifics and undescribed species

Science.gov (United States)

Inoue, Kentaro; Hayes, David M.; Harris, John L.; Johnson, Nathan A.; Morrison, Cheryl L.; Eackles, Michael S.; King, Tim; Jones, Jess W.; Hallerman, Eric M.; Christian, Alan D.; Randklev, Charles R.

2018-01-01

The Pleurobemini (Bivalvia: Unionida) represent approximately one-third of freshwater mussel diversity in North America. Species identification within this group is challenging due to morphological convergence and phenotypic plasticity. Accurate species identification, including characterisation of currently unrecognised taxa, is required to develop effective conservation strategies because many species in the group are imperiled. We examined 575 cox1 sequences from 110 currently recognised species (including 13 Fusconaia and 21 Pleurobema species) to understand phylogenetic relationships among pleurobemine species (mainly Fusconaia and Pleurobema) and to delineate species boundaries. The results of phylogenetic analyses showed no geographic structure within widespread species and illustrated a close relationship between Elliptio lanceolata and Parvaspina collina. Constraint tests supported monophyly of the genera Fusconaia and Pleurobema, including the subgenus P. (Sintoxia). Furthermore, results revealed multiple conspecifics, including P. hanleyianum and P. troschelianum, P. chattanoogaense and P. decisum, P. clava and P. oviforme, P. rubrum and P. sintoxia, F. askewi and F. lananensis, and F. cerina and F. flava. Species delimitation analyses identified three currently unrecognised taxa (two in Fusconaia and one in Pleurobema). Further investigation using additional genetic markers and other lines of evidence (e.g. morphology, life history, ecology) are necessary before any taxonomic changes are formalised.

Annotated type catalogue of the Orthalicoidea (Mollusca, Gastropoda in the Museum für Naturkunde, Berlin

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Abraham Breure

2013-03-01

Full Text Available The type status is described of 96 taxa classified within the superfamily Orthalicoidea and present in the Mollusca collection of the Museum für Naturkunde der Humboldt-Universität zu Berlin. Lectotypes are designated for the following taxa: Orthalicus elegans Rolle, 1895; Bulimus maranhonensis Albers, 1854; Orthalicus nobilis Rolle, 1895; Orthalichus tricinctus Martens, 1893. Orthalicus sphinx tresmariae is introduced as new name for Zebra sphinx turrita Strebel, 1909, not Z. quagga turrita Strebel, 1909. The following synonyms are established: Zebra crosseifischeri Strebel, 1909 = Orthalicus princeps fischeri Martens, 1893; Orthalicus isabellinus Martens, 1873 = O. bensoni (Reeve, 1849; Zebra zoniferus naesiotes Strebel, 1909 = Orthalicus undatus (Bruguière, 1789; Porphyrobaphe (Myiorthalicus dennisoni pallida Strebel, 1909 = Hemibulimus dennisoni (Reeve, 1848; Zebra delphinus pumilio Strebel, 1909 = Orthalicus delphinus (Strebel, 1909; Orthalicus (Laeorthalicus reginaeformis Strebel, 1909 = Corona perversa (Swainson, 1821; Bulimus (Eurytus corticosus Sowerby III, 1895 = Plekocheilus (Eurytus stuebeli Martens, 1885. The taxon Bulimus (Eudioptus psidii Martens, 1877 is now placed within the family Sagdidae, tentatively in the genus Platysuccinea. Appendices are included with an index to all the types of Orthalicoidea extant (including those listed by Köhler 2007 and a partial list of letters present in the correspondence archives.

Relación entre las capturas de Megapitaria squalida (Bivalvia: Veneridae y la temperatura superficial del mar en la Bahía de la Paz, Baja California Sur, México

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Mariana Vázquez Hurtado

2011-03-01

Full Text Available La almeja chocolate Megapitaria squalida es un recurso pesquero con creciente importancia en el noroeste de México al registrarse un incremento en los volúmenes de captura. Sin embargo, esta pesquería ha observado variaciones importantes en las capturas que podrían estar relacionadas con factores ambientales. Se obtuvieron datos mensuales de producción de M. squalida durante 2002- 2005 y se estimaron series de tiempo de temperatura superficial del mar en la Bahía de La Paz B.C.S. a partir de imágenes mensuales derivadas del sensor MODIS-Aqua. Los resultados indican una relación positiva significativa entre la temperatura superficial del mar y los volúmenes de captura, razón por la cual nuestro trabajo tiene como objetivo estudiar las relaciones entre capturas de Megapitaria squalida (Bivalvia: Veneridae y la temperatura superficial del mar en La Bahía de la Paz, Baja California Sur, México.

Faunistic assemblages of a sublittoral coarse sand habitat of the northwestern Mediterranean

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Eva Pubill

2011-02-01

Full Text Available The sublittoral megabenthic assemblages of a northwestern Mediterranean coarse sandy beach exploited for the bivalve Callista chione were studied. The spatial and bathymetric variability of its distinctive faunal assemblages was characterised by quantitative sampling performed with a clam dredge. The taxa studied were Mollusca Bivalvia and Gastropoda, Crustacea Decapoda, Echinodermata and Pisces, which accounted for over 99% of the total biomass. Three well-differentiated species assemblages were identified: (1 assemblage MSS (Medium Sand Shallow in medium sand (D50=0.37 mm and shallow waters (mean depth =6.5 m, (2 assemblage CSS (Coarse Sand Shallow in coarse sand (D50=0.62 mm in shallow waters (mean depth =6.7 m, and (3 assemblage CSD (Coarse Sand Deep in coarse sand (D50=0.64 mm in deeper waters (mean depth =16.2 m. Assemblage MSS was characterised by the codominance of the bivalves Mactra stultorum and Acanthocardia tuberculata. C. chione was dominant in both density and biomass in assemblages CSS and CSD. The occurrence of the crab Thia scutellata also characterised assemblage CSS, whereas the occurrence of the sea urchin Echinocardium mediterraneum characterised assemblage CSD. A depth breaking point of around 10 m determined the discontinuity between assemblages CSS and CSD, which was related to the closure depth of the beaches in the study area. Species richness was highest in the coarse sand communities; however, Shannon-Wiener diversity and Pielou equitability indexes were higher in the shallow fine sand community.

Homology and homoplasy of swimming behaviors and neural circuits in the Nudipleura (Mollusca, Gastropoda, Opisthobranchia)

Science.gov (United States)

Newcomb, James M.; Sakurai, Akira; Lillvis, Joshua L.; Gunaratne, Charuni A.; Katz, Paul S.

2012-01-01

How neural circuit evolution relates to behavioral evolution is not well understood. Here the relationship between neural circuits and behavior is explored with respect to the swimming behaviors of the Nudipleura (Mollusca, Gastropoda, Opithobranchia). Nudipleura is a diverse monophyletic clade of sea slugs among which only a small percentage of species can swim. Swimming falls into a limited number of categories, the most prevalent of which are rhythmic left–right body flexions (LR) and rhythmic dorsal–ventral body flexions (DV). The phylogenetic distribution of these behaviors suggests a high degree of homoplasy. The central pattern generator (CPG) underlying DV swimming has been well characterized in Tritonia diomedea and in Pleurobranchaea californica. The CPG for LR swimming has been elucidated in Melibe leonina and Dendronotus iris, which are more closely related. The CPGs for the categorically distinct DV and LR swimming behaviors consist of nonoverlapping sets of homologous identified neurons, whereas the categorically similar behaviors share some homologous identified neurons, although the exact composition of neurons and synapses in the neural circuits differ. The roles played by homologous identified neurons in categorically distinct behaviors differ. However, homologous identified neurons also play different roles even in the swim CPGs of the two LR swimming species. Individual neurons can be multifunctional within a species. Some of those functions are shared across species, whereas others are not. The pattern of use and reuse of homologous neurons in various forms of swimming and other behaviors further demonstrates that the composition of neural circuits influences the evolution of behaviors. PMID:22723353

Volutidae (Mollusca: Gastropoda) of the Lakhra Formation (Earliest Eocene, Sindh, Pakistan): systematics, biostratigraphy and paleobiogeography.

Science.gov (United States)

Merle, Didier; Pacaud, Jean-Michel; Métais, Grégoire; Bartolini, Annachiara; Lashari, Rafiq A; Brohi, Imdad A; Solangi, Sarfraz H; Marivaux, Laurent; Welcomme, Jean-Loup

2014-06-27

The paleobiodiversity of the Volutidae (Mollusca: Gastropoda) of the Ranikot Group (Sindh, Pakistan) and particularly of the Lakhra Formation (SBZ 5 biozone, Earliest Eocene), is reconsidered on the basis of new material collected during recent field trips. Ten new species are described (Mitreola brohii sp. nov., Lyrischapa vredenburgi sp. nov., L. brevispira sp. nov., Athleta (Volutopupa) citharopsis sp. nov., A. (Volutocorbis) lasharii sp. nov., Volutilithes welcommei sp. nov., V. sindhiensis sp. nov., Pseudaulicina coxi sp. nov., Sindhiluta lakhraensis sp. nov. and Pakiluta solangii sp. nov.) and one species is in open nomenclature (Lyria sp.). Three new genera are described: Lyriopsis gen. nov. [Volutinae, ?Lyriini, type species: Lyriopsis cossmanni (Vredenburg, 1923)], Sindhiluta gen. nov. [Volutilithinae, type species: Sindhiluta lakhraensis n. sp.] and Pakiluta gen. nov. [?Volutodermatinae, type species: Pakiluta solangii n. sp.]. Two new combinations are proposed: Lyriopsis cossmanni (Vredenburg, 1923) comb. nov. and Athleta (Volutopupa) intercrenatus (Cossmann & Pissarro, 1909) comb. nov. Lectotypes are designated for Lyria cossmanni Vredenburg, 1923, L. feddeni Vredenburg, 1923, Volutospina noetlingi Cossmann & Pissarro, 1909, V. intercrenata Cossmann & Pissarro, 1909 and Athleta (Volutocorbis) victoriae Vredenburg, 1923. With 21 species, this volutid fauna is the most diverse recorded from the Tethys Ocean during Earliest Eocene time. The assemblage is characterized by a strong turnover marked by regional speciation and the appearance of many western Tethyan invaders. Although at the species level, the assemblage documents a strong provincialism, at the genus level, the high number of shared genera between Eastern Tethyan and Old World Tethyan realms begins a phase of long-term homogeneity of volutid assemblages from the Tethyan paleobiogeographic province.

Seasonal variation in the abundance and distribution of Anomalocardia flexuosa (Mollusca, Bivalvia, Veneridae in an estuarine intertidal plain

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Jacqueline S. Silva-Cavalcanti

2018-02-01

Full Text Available Spatial and temporal density and biomass of the infaunal mollusk Anomalocardia flexuosa (Linnaeus, 1767 evaluated a tidal plain at Goiana estuary (Northeast Brazil. Three hundred and sixty core samples were taken during an annual cycle from three intertidal habitats (A, B and C. Shell ranged from 2.20 to 28.48 mm (15.08 ± 4.08 mm. Recruitment occurred more intensely from January to March. Total (0–1,129 g m−2 differed seasons (rainy and dry, with highest values in the early rainy season (221.0 ± 231.44 g m−2; and lowest values in the late dry season (57.34 ± 97 g m−2. The lowest occurred during the late rainy (319 ± 259 ind m−2 and early dry (496 ± 607 ind m−2 seasons. Extreme environmental situations (e.g., river flow, salinity and water temperature at the end of each season also affected density ranges (late dry: 0–5,798 ind m−2; late rainy: 0–1,170 ind m−2. A. flexuosa in the Goiana estuary presented a dominance of juvenile individuals (shell length < 20 mm, with high biomass main the recruitment period. Average shell length, density and biomass values suggest overfishing of the stock unit. A. flexuosa is an important food and income resource along its whole distribution range. The species was previously also known as Anomalocardia brasiliana (Gmelin, 1791.

Immunochemical localization of ribulose-1,5-bisphosphate carboxylase in the symbiont-containing gills of Solemya velum (Bivalvia : Mollusca)

NARCIS (Netherlands)

Cavanaugh, Colleen M.; Abbott, Marilyn S.; Veenhuis, Marten

1988-01-01

The distribution of the Calvin cycle enzyme ribulose-1,5-bisphosphate carboxylase (RbuP2Case; EC 4.1.1.39) was examined by using two immunological methods in tissues of Solemya velum, an Atlantic coast bivalve containing putative chemoautotrophic symbionts. Antibodies elicited by the purified large

Immunochemical localization of ribulose-1,5-bisphosphate carboxylase in the symbiont-containing gills of Solemya velum (Bivalvia: Mollusca).

Science.gov (United States)

Cavanaugh, C M; Abbott, M S; Veenhuis, M

1988-10-01

The distribution of the Calvin cycle enzyme ribulose-1,5-bisphosphate carboxylase (RbuP(2)Case; EC 4.1.1.39) was examined by using two immunological methods in tissues of Solemya velum, an Atlantic coast bivalve containing putative chemoautotrophic symbionts. Antibodies elicited by the purified large subunit of RbuP(2)Case from tobacco (Nicotiana tabacum) cross-reacted on immunoblots with a protein of similar molecular mass occurring in extracts of the symbiont-containing gill tissue of S. velum. No cross-reactivity was detected in symbiont-free tissue extracts. The antiserum also cross-reacted in immunoblots with proteins of Thiobacillus neapolitanus, a free-living sulfuroxidizing chemoautotroph whose RbuP(2)Case has been well characterized. In protein A-gold immunoelectron microscopy studies, this antiserum consistently labeled the symbionts but not surrounding host gill tissue, indicating that the symbionts are responsible for the RbuP(2)Case activity.

Effect of heavy metals (Cu, Cd and Pb) on aspartate and alanine aminotransferase in Ruditapes philippinarum (Mollusca: Bivalvia)

International Nuclear Information System (INIS)

Blasco, J.; Puppo, J.

1999-01-01

The accumulation of cadmium, copper and lead and their effects on aspartate and alanine aminotransferases in digestive gland, gills, foot and soft body in the clam Ruditapes philippinarum were examined. The animals were exposed to different concentrations: Cd (200-600 μg·l -1 ), Pb (350-700 μg·l -1 ) and Cu (10-20 μg·l -1 ) for 7 days. The highest concentrations were found in digestive gland for cadmium and copper, and in gills for lead, and the lowest values were observed in the foot. Aspartate aminotransferase activity (AST), in general, was not inhibited by cadmium, lead or copper during the exposure. Only in clams exposed to cadmium (600 μg·l -1 , 7 days) and copper (20 μg·l -1 , 5 days) were observed significant differences (P -1 . A significant correlation (P<0.05) was observed between ALT and metal accumulation for cadmium, copper and lead in gills. In the case of soft body, only cadmium and lead showed a significant correlation. In summary, R. philippinarum can be considered a bioindicator species for cadmium and lead accumulation and ALT could be useful as biomarker of sublethal stress for these metals in soft tissues and gills. Only gills can be considered an adequate target tissue for copper. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

Effect of zinc and benzene on respiration and excretion of mussel larvae (Perna perna (Linnaeus, 1758 (Mollusca; Bivalvia

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RADLVC. Jorge

Full Text Available The presence of pollutants in the ocean may affect different physiological parameters of animals. Oxygen consumption and ammonia excretion were evaluated in D-shaped larvae of mussels (Perna perna exposed to zinc sulphate (ZnSO4 and benzene (C6H6. When compared to the control group, both pollutants presented a significant reduction in oxygen consumption. A reduction in the ammonia excretion was also observed, both for ZnSO4 and C6H6 and also in the oxygen consumption. The results indicate that anaerobic metabolism may occur at the beginning of P. perna mussels development, as observed in veliger larvae. The O:N ratio under experimental conditions showed low values indicating that catabolism in veliger larvae was predominantly proteic.

Isolation and Characterization of the First Microsatellite Markers for the Endangered Relict Mussel Hypanis colorata (Mollusca: Bivalvia: Cardiidae

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Luis Ovidiu Popa

2011-01-01

Full Text Available Hypanis colorata (Eichwald, 1829 (Cardiidae: Lymnocardiinae is a bivalve relict species with a Ponto-Caspian distribution and is under strict protection in Romania, according to national regulations. While the species is depressed in the western Black Sea lagoons from Romania and Ukraine, it is also a successful invader in the middle Dniepr and Volga regions. Establishing a conservation strategy for this species or studying its invasion process requires knowledge about the genetic structure of the species populations. We have isolated and characterized nine polymorphic microsatellite markers in H. colorata. The number of alleles per locus ranged from 4 to 28 and the observed heterozygosity ranged from 0.613 to 1.000. The microsatellites developed in the present study are highly polymorphic and they should be useful for the assessment of genetic variation within this species.

Assessing metal contamination from construction and demolition (C&D) waste used to infill wetlands: using Deroceras reticulatum (Mollusca: Gastropoda).

Science.gov (United States)

Staunton, John A; Mc Donnell, Rory J; Gormally, Michael J; Williams, Chris D; Henry, Tiernan; Morrison, Liam

2014-11-01

Large quantities of construction and demolition waste (C&D) are produced globally every year, with little known about potential environmental impacts. In the present study, the slug, Deroceras reticulatum (Mollusca: Gastropoda) was used as the first biomonitor of metals (Ag, As, Ba, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Sb, Se, Ti, Tl, V and Zn) on wetlands post infilling with construction and demolition (C&D) waste. The bioaccumulation of As, Ba, Cd, Co, Sb, Se and Tl were found to be significantly elevated in slugs collected on C&D waste when compared to unimproved pastures (control sites), while Mo, Se and Sr had significantly higher concentrations in slugs collected on C&D waste when compared to known contaminated sites (mining locations), indicating the potential hazardous nature of C&D waste to biota. Identifying exact sources for these metals within the waste can be problematic, due to its heterogenic nature. Biomonitors are a useful tool for future monitoring and impact studies, facilitating policy makers and regulations in other countries regarding C&D waste infill. In addition, improving separation of C&D waste to allow increased reuse and recycling is likely to be effective in reducing the volume of waste being used as infill, subsequently decreasing potential metal contamination.

Comunidades de quitones (Mollusca: Polyplacophora de la Bahía de La Paz, Baja California Sur, México

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Cedar I García Ríos

2007-03-01

Full Text Available A las ocho especies de poliplacóforos registradas en Bahía de la Paz, Baja California Sur, México, o cerca de ella, agregamos a Lepidochitona beanii, Chaetopleura lurida, Stenoplax limaciformis, S. mariposa, Lepidozona clathrata, L. serrata y Acanthochitona arragonites. El análisis de las comunidades estudiadas usando técnicas de ordenación sugiere que podría relacionarse la exposición al oleaje con la riqueza y la diversidad de especies. La comunidad recolectada en condiciones intermedias de exposición al oleaje presentó mayor número de especies y mayor diversidad de acuerdo con el índice de Shannon.Polyplacophoran communities (Mollusca: Polyplacophora at Bahía de La Paz, Baja California Sur, México. Eight species of polyplacophorans have been reported from La Bahía de la Paz, Baja California Sur, Mexico. We add Lepidochitona beanii, Chaetopleura lurida, Stenoplax limaciformis, S. mariposa, Lepidozona clathrata, L. serrata and Acanthochitona arragonites, increasing the known number of species to 15. Ordination analysis of five chiton communities at the site suggests a correlation of wave exposure to species composition and diversity: communities with intermediate wave exposure have more species (richness and higher diversity (Shannon’s index. Rev. Biol. Trop. 55 (1: 177-182. Epub 2007 March. 31.

ON THE PALEOFAUNA INVERTEBRATES (MOLLUSCA, ARTROPODA; INSECTA OF DIATOMITE DEPOSITS OF SHAMB–1 LOCALITY (SISIAN SUITE, EARLY PLEISTOCENE, ARMENIA

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М. A. Маrjanyan

2016-01-01

Full Text Available Aim. The study of fossil insects from diatomaceous sediments of Shamb-1 locality of Sisian Suite (Early Pleistocene. The collection of fossils plants and animals of Institute of Botany of NAS RA and authors' findings served as material for study.Methods. The material is processed and prepared for study by conventional methods in paleontology for prints and fossils of insects from diatomaceous sediments. There are 654 samples studied: 2 samples were with mollusks’ imprints and 652 samples with imprints of insects, from which preserved marks on 291samples allowed to identify them up to order, family, genus and species.Results. The studied material refers to the Mollusca and Arthropoda (Insecta types. Insects are represented by species of orders Orthoptera (2 fam., Homoptera (1 fam., Heteroptera (2 fam., Coleoptera (15 fam., Hymenoptera (2 fam., Diptera (1 fam.. Coleopteras dominate among them and are presented with following species of the family – Carabidae, Dytiscidae, Hydrophilidae, Histeridae, Staphylinidae, Silphidae, Elateridae, Buprestidae, Lampyridae, Scarabaeidae, Chrysomelidae, Tenebrionidae, Coccinellidae, Cerambycidae, Curculionidae.Main conclusions. An analysis of the taxonomic composition of paleofauna was done, which corresponds to the recent fauna and with considering modern ecological characteristics of systematical groups and species. In the investigated location of Shamb-1 a version is suggested about the palaeolandscapes and palaeoclimate in the Early Pleistocene.

Comparative studies on the histology and ultrastructure of the siphons of two species of Tellinidae (Mollusca: Bivalvia from Brazil

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João E.V.V. Vitonis

2012-06-01

Full Text Available Despite the great importance of the siphons for infaunal bivalves, only a few studies have examined their tissues using histology techniques or scanning electron microscopy. In the present study, the siphons of Tellina lineata Turton, 1819 and Macoma biota Arruda & Domaneschi, 2005 were investigated. The siphon walls are composed by a series of muscle sheets of longitudinal ("L", circular ("C" and radial ("R" fibers, with a clear pattern common to both species: there is a main median longitudinal layer (Lm, and two peripheral circular layers, one inner (Ci and one outer (Co, near the epithelia. A median circular layer (Cm separates an internal (Lmi from an outer (Lmo median longitudinal layer. Further, the Co is split by a thin outer longitudinal layer (Lo, forming Coi and Coo layers, the former being obliquely oriented. Thin radial fibers (R delimit clear packages of Lmi and Lmo fibers. In each siphon, there are six longitudinal nerve cords, running within the Lmi layer, adjacent to the Cm. The inhalant and exhalant siphons of M. biota are very similar in structure, but the Lmo of the exhalant siphon is almost twice as thick as its Lmi, while in the inhalant siphon these layers have similar thicknesses; the Coi is very thick, especially in the exhalant siphon. The inhalant siphon of T. lineata is very similar to that of M. biota, differing only with respect to the thickness of the Coi, which in the former species is not as well developed as in the latter. The Lmo of the exhalant siphon of T. lineata is by far the most developed layer, with the Lmi represented only by uniseriate small cells; in the vicinities of the nerve cords, the Cm is split in two layers. The epithelia of both siphons of M. biota and T. lineata bear ciliated receptors, which were difficult to observe as they were frequently covered with mucus. It was possible to observe that cilia are present in both species, differing in length and in the number per receptor between the inhalant and exhalant siphons, and between the species. Detailed comparisons among the siphons of M. biota and T. lineata and other bivalve species are very difficult, because of at least two reasons. First, each investigator has used different methods to prepare and observe the siphons through histological sections; and second, different nomenclatural schemes are used to describe the musculature of the siphons, causing confusion when the same layers are compared among different species. In order to unify the nomenclature of tissue layers of the bivalve siphons, we now propose a scheme to name these layers based on topological homology.

Symbiotic relationship between the carapid fish Onuxodon fowleri (Ophidiiformes: Carapidae and the pearl oyster Pinctada margaritifera (Mollusca: Bivalvia: Pteriidae

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Orphal Colleye

2018-03-01

Full Text Available At Makemo Atoll (French Polynesia, the carapid fish Onuxodon fowleri lives in symbiosis with the black-lip pearl oyster Pinctada margaritifera. Although the symbiont seems to live inside its host bivalve by using it as a shelter, additional data are still needed to better understand the exact nature of this association. For this purpose, we implemented an approach using stable isotope ratios of carbon (13C/12C and nitrogen (15N/14N. The δ13C and δ15N values were measured in tissues of the pearl oyster (gonads, gills, mantle and muscles, white muscle tissue from the fish and other food sources. This stable isotope approach was also complemented by the analysis of stomach contents in the carapid fish. Overall, the isotopic compositions measured in the present study support a commensal relationship between O. fowleri and P. margaritifera. In addition, our isotopic data bring new information about another guest living inside P. margaritifera, namely the palaemonid shrimp Conchodytes meleagrinae. Based on the δ13C and δ15N values, it appears that the shrimp might feed on the bivalve gonads.

Aspects of the biology of Mya arenaria and Ensis spp. (Mollusca; Bivalvia) in the Irish Sea and adjacent areas

OpenAIRE

Cross, Maud E.

2014-01-01

This study was undertaken to investigate the general biology, including the reproductive cycle and health status, of two clam taxa in Irish waters, with particular reference to the Irish Sea area. Monthly samples of the soft shell clam, Mya arenaria, were collected from Bannow Bay, Co. Wexford, Ireland, for sixteen months, and of the razor clam, Ensis spp. from the Skerries region (Irish Sea) between June 2010 and September 2011. In 2010, M. arenaria in Bannow Bay matured over the summer mont...

Taxocenosis of mollusks and crustaceans on roots of rhizophora mangle (rhizophoraceae) at Cispata Bay, Cordoba, Colombia

International Nuclear Information System (INIS)

Quiros R, Jorge Alexander; Arias, Jorge Enrique

2013-01-01

Despite the existing knowledge on the ecology of mangroves at Cispata Bay, few studies have focused on the association of invertebrates on red mangrove roots, so between December 2010 and September 2011, it was characterized Taxocenosis of mollusks and crustaceans on roots of rhizophora mangle in two study sites at Cispata Bay, Colombia. For the collections of biological material were randomly taken three red mangrove roots with a diameter homogeneous by sampling station. Mollusks and crustaceans were obtained from the root surface with a scraping knife then were removed and fixed in 10 % formalin for later identification to species using specialized taxonomic keys. of the 12289 individuals collected in the four samples, 10470 belonged to the phylum Mollusca (85,2 %) and the remaining 1819 to subphylum Crustacea (14,8 %). for mollusks were identified 14 species distributed in 11 families and two classes; bivalvia and gastropoda. for crustaceans were identified 24 species distributed in 16 families and four orders; sessillia, decapoda, isopoda and amphipoda. in both sectors sampling mytella charruana, balanuseburneus and crassostrea rhizophorae were the most important species in terms of abundance, however mollusks like m. charruana and B. eburneus have a great ability to adapt and adjust to changing hydroclimatic, which was reflected in the dominance of these species in the sector with the greatest influence Sinu River. The presence of crustaceans Petrolisthes armatus and Aratus pisonii in the sector with more proximity to the Caribbean Sea indicate that are species with great mobility and physiological adaptation mechanisms.

Explaining Away Intuitions

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Jonathan Ichikawa

2009-12-01

Full Text Available What is it to explain away an intuition? Philosophers regularly attempt to explain intuitions away, but it is often unclear what the success conditions for their project consist in. I attempt to articulate some of these conditions, taking philosophical case studies as guides, and arguing that many attempts to explain away intuitions underestimate the challenge the project of explaining away involves. I will conclude, therefore, that explaining away intuitions is a more difficult task than has sometimes been appreciated; I also suggest, however, that the importance of explaining away intuitions has often been exaggerated.

Explaining Physics – What Skills does a good Explainer Need?

CERN Multimedia

CERN. Geneva; Bartels, Hauke

2018-01-01

Explaining physics in a way that it is both scientifically correct and comprehensible is a highly demanding practice. But are explanations an effective way to teach physics? Under which circumstances should a physics teacher explain – and is there such a thing as a guideline for effective instructional explanations? Of course, explaining is more than just presenting content knowledge in clear language – but what more? In our talk, we want to discuss empirical studies on instructional explanations from science education and psychology to address these questions. Among other things, we will refer to results from a large study aiming to research whether teacher education contributes to the development of explaining skills. Besides, we will give insights into a project that seeks to measure explaining skills with an interactive online test instrument.

Detection limits of absorbed dose of ionizing radiation in molluscan shells as determined by e.p.r. spectroscopy

International Nuclear Information System (INIS)

Stachowicz, W.; Michalik, J.; Burlinska, G.; Sadlo, J.; Dziedzic-Goclawska, A.; Ostrowski, K.

1995-01-01

The exposure of waters to ionizing radiation from radionuclides imprisoned in dumped nuclear waste containers, freed in nuclear submarine accidents or released in underwater magma eruptions are difficult to be evaluated by conventional radiometric methods. Ionizing radiation evokes stable paramagnetic centers in crystalline lattice of mineral components in bone skeletons of mammals and fishes as well as in exoskeletons of mollusca. They give rise in e.p.r. to specific, extremely stable signals which are proposed to be applied as indicators of radiation exposure levels. In the present study the e.p.r. detection limits of the dose of ionizing radiation absorbed in shells of fresh water and marine mollusca (selected species) have been estimated. It has been found that with fresh water mollusca the dose of 1-2 Gy can be detected, while the sea water mollusca by one order of magnitude lower, i.e. about 0.1 Gy. (author)

Abyssal fauna of the UK-1 polymetallic nodule exploration area, Clarion-Clipperton Zone, central Pacific Ocean: Mollusca.

Science.gov (United States)

Wiklund, Helena; Taylor, John D; Dahlgren, Thomas G; Todt, Christiane; Ikebe, Chiho; Rabone, Muriel; Glover, Adrian G

2017-01-01

We present the first DNA taxonomy publication on abyssal Mollusca from the Clarion-Clipperton Zone (CCZ), central Pacific ocean, using material collected as part of the Abyssal Baseline (ABYSSLINE) environmental survey cruise 'AB01' to the UK Seabed Resources Ltd (UKSRL) polymetallic-nodule exploration area 'UK-1' in the eastern CCZ. This is the third paper in a series to provide regional taxonomic data for a region that is undergoing intense deep-sea mineral exploration for high-grade polymetallic nodules. Taxonomic data are presented for 21 species from 42 records identified by a combination of morphological and genetic data, including molecular phylogenetic analyses. These included 3 heterodont bivalves, 5 protobranch bivalves, 4 pteriomorph bivalves, 1 caudofoveate, 1 monoplacophoran, 1 polyplacophoran, 4 scaphopods and 2 solenogastres. Gastropoda were recovered but will be the subject of a future study. Seven taxa matched published morphological descriptions for species with deep Pacific type localities, and our sequences provide the first genetic data for these taxa. One taxon morphologically matched a known cosmopolitan species but with a type locality in a different ocean basin and was assigned the open nomenclature ' cf ' as a precautionary approach in taxon assignments to avoid over-estimating species ranges. One taxon is here described as a new species, Ledella knudseni sp. n. For the remaining 12 taxa, we have determined them to be potentially new species, for which we make the raw data, imagery and vouchers available for future taxonomic study. The Clarion-Clipperton Zone is a region undergoing intense exploration for potential deep-sea mineral extraction. We present these data to facilitate future taxonomic and environmental impact study by making both data and voucher materials available through curated and accessible biological collections.

Abyssal fauna of the UK-1 polymetallic nodule exploration area, Clarion-Clipperton Zone, central Pacific Ocean: Mollusca

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Helena Wiklund

2017-10-01

Full Text Available We present the first DNA taxonomy publication on abyssal Mollusca from the Clarion-Clipperton Zone (CCZ, central Pacific ocean, using material collected as part of the Abyssal Baseline (ABYSSLINE environmental survey cruise ‘AB01’ to the UK Seabed Resources Ltd (UKSRL polymetallic-nodule exploration area ‘UK-1’ in the eastern CCZ. This is the third paper in a series to provide regional taxonomic data for a region that is undergoing intense deep-sea mineral exploration for high-grade polymetallic nodules. Taxonomic data are presented for 21 species from 42 records identified by a combination of morphological and genetic data, including molecular phylogenetic analyses. These included 3 heterodont bivalves, 5 protobranch bivalves, 4 pteriomorph bivalves, 1 caudofoveate, 1 monoplacophoran, 1 polyplacophoran, 4 scaphopods and 2 solenogastres. Gastropoda were recovered but will be the subject of a future study. Seven taxa matched published morphological descriptions for species with deep Pacific type localities, and our sequences provide the first genetic data for these taxa. One taxon morphologically matched a known cosmopolitan species but with a type locality in a different ocean basin and was assigned the open nomenclature ‘cf’ as a precautionary approach in taxon assignments to avoid over-estimating species ranges. One taxon is here described as a new species, Ledella knudseni sp. n. For the remaining 12 taxa, we have determined them to be potentially new species, for which we make the raw data, imagery and vouchers available for future taxonomic study. The Clarion-Clipperton Zone is a region undergoing intense exploration for potential deep-sea mineral extraction. We present these data to facilitate future taxonomic and environmental impact study by making both data and voucher materials available through curated and accessible biological collections.

Molluscan Evolutionary Development

DEFF Research Database (Denmark)

Wanninger, Andreas Wilhelm Georg; Koop, Damien; Moshel-Lynch, Sharon

2008-01-01

Brought together by Winston F. Ponder and David R. Lindberg, thirty-six experts on the evolution of the Mollusca provide an up-to-date review of its evolutionary history. The Mollusca are the second largest animal phylum and boast a fossil record of over 540 million years. They exhibit remarkable...

Benthic macroinvertebrates in Italian rice fields

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Daniela Lupi

2013-02-01

Full Text Available Rice fields can be considered man-managed temporary wetlands. Five rice fields handled with different management strategies, their adjacent channels, and a spring were analysed by their benthic macroinvertebrate community to i evaluate the role of rice agroe- cosystem in biodiversity conservation; ii find indicator species which can be used to compare the ecological status of natural wetlands with rice agroecosystems; and iii find the influence of environmental variables on biodiversity. Different methods of data analysis with increasing degree of complexity – from diversity index up to sophisticated multivariate analysis – were used. The investigation provided a picture of benthic macroinvertebrates inhabiting rice agroecosystems where 173 taxa were identified, 89 of which detected in rice paddies. Among them, 4 phyla (Mollusca, Annelida, Nematomorpha, and Arthropoda, 8 classes (Bivalvia, Gastropoda, Oligochaeta, Hirudinea, Gordioida, Insecta, Branchiopoda, and Malacostraca, 24 orders, 68 families, 127 genera and 159 species have been found. Ten threatened and 3 invasive species were detected in the habitats examined. The information obtained by the different methods of data analysis allowed a more comprehensive view on the value of the components of rice agroecosystems. Data analyses highlighted significant differences between habitats (feeding channel and rice field, with higher diversity observed in channels, and emphasised the role of the water chemical-physical parameters. The period of water permanence in rice fields resulted to be only one of the factors influencing the community of benthic macroinvertebrates. The presence of rare/endangered species allowed characterising some stations, but it was less informative about management strategies in rice paddies because most of these species were absent in rice fields.

Marine mollusca of oxygen isotope stages of the last 2 million years in New Zealand. Part 1, Revised generic positions and recognition of warm-water and cool-water migrants

International Nuclear Information System (INIS)

Beu, A.G.

2004-01-01

Warm-water molluscs were transported to Wanganui Basin from the northeastern North Island during Pleistocene time as planktotrophic larvae. This is not possible at present, so their occurrence in Wanganui Basin correlates with breaches of the Auckland isthmus during high sea levels. The end of Nukumaruan time is clearly defined by the extinction of 29 genera of molluscs (most only locally) during this stage, including 15 at the end. The extinction likely was caused by the initial closure of the Auckland isthmus. Migrants to Wanganui from the northeastern North Island indicate that breaches of the isthmus during interglacials commenced in oxygen isotope stage (OIS) 25, just before the mid-Pleistocene transition (MPT). Appearances of taxa from Australia at Wanganui during OIS 17-9 therefore indicate that warm-water taxa were transported to New Zealand during interglacial maxima after the MPT. The migrants provide the first molluscan biostratigraphy at the OIS scale. The Castlecliffian/Nukumaruan boundary, at the base of Ototoka tephra at Ototoka Beach, Wanganui, falls within OIS 57, with an age of c. 1.63 Ma. It is also dated at 1.63 Ma by the position with respect to the geomagnetic polarity time-scale of three chemically indistinguishable tephra in ODP core 1123. This paper presents the first results of a reassessment of the taxonomy and time ranges of the fossil marine molluscan fauna that occupied New Zealand during the last 2 m.y. (latest Pliocene-Holocene). Time ranges are compiled in oxygen isotope stages rather than in the traditional 'local' (or regional) stages in use in New Zealand. This should provide precision in time ranges of the order of 40,000-100,000 yr, rather than the 0.34-1.3 m.y. duration of New Zealand local stages of the latest Neogene (Nukumaruan, Castlecliffian, and Haweran Stages). The reassessment is aimed also, though, at providing evidence from Mollusca of climate change over this period. Much useful information on paleoclimates can be

Chaetogaster limnaei (annelida: oligochaeta) as a parasite of the zebra mussel Dreissena polymorpha, and the quagga mussel Dreissena bugensis (mollusca: bivalvia).

Science.gov (United States)

Conn, D B; Ricciardi, A; Babapulle, M N; Klein, K A; Rosen, D A

1996-01-01

Dreissenid mussels, Dreissena polymorpha and D. bugensis, were found to be infected by the naidid oligochaete Chaetogaster limnaei at four sites in the St. Lawrence River. This is the first report of this species infecting dreissenids anywhere in the world. Most worms inhabited the mantle cavity, where they caused erosion of the mantle and gill epithelia as determined by histopathological examination. Others penetrated various tissues; one had invaded the ovary and was feeding on oocytes and ovarian tissues. Of 606 mussels examined, 166 (27.4%) harbored at least 1 C. limnaei. The prevalence varied between 1% and 80%, depending on the collection site and date. The worms were slightly but significantly more prevalent in D. bugensis than in D. polymorpha. The intensity ranged from 1 to 18 worms per infected host. Variations in prevalence and intensity were not related to the size or sex of the host, but the data did suggest some seasonality.

Genetic diversity and population genetic analysis of Donax vittatus (Mollusca: Bivalvia) and phylogeny of the genus with mitochondrial and nuclear markers

Science.gov (United States)

Fernández-Pérez, Jenyfer; Froufe, Elsa; Nantón, Ana; Gaspar, Miguel B.; Méndez, Josefina

2017-10-01

In this study, the genetic diversity of Donax vittatus across the Iberian Peninsula was investigated using four mitochondrial (COI, Cytb, 16S F and M types) and three nuclear (H3, 18S and 28S) genes. These same molecular markers were also sequenced in D. semistriatus and D variegatus to address the phylogenetic relationships of the species of the genus Donax common along the European coasts. Our results showed high haplotype diversity in combination with a low nucleotide diversity and a star-shaped network with a predominant haplotype, indicating a recent population expansion for the examined sampling sites of D. vittatus. Furthermore, analyses of population differentiation performed with COI mitochondrial marker, including global FST estimation and pairwise FST values, indicated the non-existence of significant genetic structure in D. vittatus of Northwest Iberian populations. Because these localities show a high genetic similarity, we suggest that D. vittatus could be a potentially alternative exploitable resource, as complement to the D. trunculus fisheries, whose natural stocks have decreased dramatically in some areas. Furthermore, we present for the first time, evidence of DUI in the clams D. vittatus and D. semistriatus.

Microbial Diseases of Bivalve Mollusks: Infections, Immunology and Antimicrobial Defense.

Science.gov (United States)

Zannella, Carla; Mosca, Francesco; Mariani, Francesca; Franci, Gianluigi; Folliero, Veronica; Galdiero, Marilena; Tiscar, Pietro Giorgio; Galdiero, Massimiliano

2017-06-17

A variety of bivalve mollusks (phylum Mollusca, class Bivalvia) constitute a prominent commodity in fisheries and aquacultures, but are also crucial in order to preserve our ecosystem's complexity and function. Bivalve mollusks, such as clams, mussels, oysters and scallops, are relevant bred species, and their global farming maintains a high incremental annual growth rate, representing a considerable proportion of the overall fishery activities. Bivalve mollusks are filter feeders; therefore by filtering a great quantity of water, they may bioaccumulate in their tissues a high number of microorganisms that can be considered infectious for humans and higher vertebrates. Moreover, since some pathogens are also able to infect bivalve mollusks, they are a threat for the entire mollusk farming industry. In consideration of the leading role in aquaculture and the growing financial importance of bivalve farming, much interest has been recently devoted to investigate the pathogenesis of infectious diseases of these mollusks in order to be prepared for public health emergencies and to avoid dreadful income losses. Several bacterial and viral pathogens will be described herein. Despite the minor complexity of the organization of the immune system of bivalves, compared to mammalian immune systems, a precise description of the different mechanisms that induce its activation and functioning is still missing. In the present review, a substantial consideration will be devoted in outlining the immune responses of bivalves and their repertoire of immune cells. Finally, we will focus on the description of antimicrobial peptides that have been identified and characterized in bivalve mollusks. Their structural and antimicrobial features are also of great interest for the biotechnology sector as antimicrobial templates to combat the increasing antibiotic-resistance of different pathogenic bacteria that plague the human population all over the world.

Plagiarism explainer for students

OpenAIRE

Barba, Lorena A.

2016-01-01

A slide deck to serve as an explainer of plagiarism in academic settings, with a personal viewpoint. For my students.Also on SpeakerDeck:https://speakerdeck.com/labarba/plagiarism-explainer-for-students(The slide viewer on SpeakerDeck is much nicer.)

Distribución del género Diplodon (Mollusca: Bivalvia: Hyriidae en territorio Argentino mediante el uso de Colecciones Biológicas

Directory of Open Access Journals (Sweden)

Santiago Hernán Torres

2013-10-01

Full Text Available Los bivalvos nacaríferos dulciacuícolas (“náyades”, son especies infaunales, endémicas de la RegiónNeotropical, pertenecientes a las familias Hyriidae (Swaison, 1840 y Etheriidae (Swaison, 1840. La alteración del ambiente y la competencia con especies invasoras como Corbicula fluminea (Müller, 1774 y Limnoperna fortunei (Dunker, 1857, impactan sobre las poblaciones naturales. En esta comunicación, se presenta el inicio de un Proyecto de investigación sobre la distribución geográfica de las especies del género Diplodon en la Argentina. Estas especies son un componente importante de la infauna de los cuerpos lóticos y lénticos, viviendo en fondos limosos, limo-arenosos, excepcionalmente en sustratos duros, con un régimen nutricio filtrador, teniendo un papel importante como recicladores de materia orgánica. Conocer la distribución de los bivalvos pertenecientes al género Diplodon en el territorio Argentino permitirá el reconocimiento de potenciales áreas prioritarias para su conservación. Sobre la base de la bibliografía disponible y los ejemplares de las especies del genero Diplodon depositados en la Colección Malacológica del Museo de La Plata (FCNyM-UNLP, se confeccionó una matriz de datos que incluye la identificación del ejemplar, la colección en que se encuentra depositado, el número de catálogo, la localidad y la fecha de colecta. Cada localidad fue ubicada mediante el uso de cartas geográficas de Argentina y revisiones bibliográficas en imágenes satelitales de GoogleEarth, asignando las coordenadas para cada punto. Como resultado del trabajo se obtiene la distribución de estas especies nativas y se discute el grado de solapamiento con las dos especies de bivalvos invasores y el impacto de actividades humanas. 

Characterization of nine microsatellite markers and development of multiplex PCRs for the Chinese huge musel Anodonta (Sinanodonta) woodiana Lea, 1834 (Mollusca, Bivalvia)

Czech Academy of Sciences Publication Activity Database

Popa, O. P.; Bartáková, Veronika; Bryja, Josef; Reichard, Martin; Popa, L. O.

2015-01-01

Roč. 60, June (2015), s. 234-237 ISSN 0305-1978 R&D Projects: GA ČR GA13-05872S Institutional support: RVO:68081766 Keywords : Invasive species * SSRs * Population genetics * Unionidae Subject RIV: EG - Zoology Impact factor: 0.988, year: 2015

Occurrence, population dynamics and habitat characterization of Mytella guyanensis (Lamarck, 1819 (Mollusca, Bivalvia in the Paraíba do Norte river estuary

Directory of Open Access Journals (Sweden)

Alberto Kioharu Nishida

1995-01-01

Full Text Available A survey of Mytellaguyanensis occurrence and population dynamics were performed in the Paraíba do Norte river estuary. The characterization and the influence of temperature, salinity and substrate, as well as the associated fauna and flora on the population were also examined. Mytella guyanensis lives buried in the substrate of the mangrove intertidal zone of the Paraíba do Norte river estuary, from the mouth to 24 km upriver. Average annual density of this bivalve species was 5.2 individuals per m², with a predominantly aggregated distribution. The most frequent size was between 4.5 and 5.5 cm in length. Analysis of the substrate demonstrated the presence of two types of substrates in relation to the percentage of silt and clay and the water content. Besides interfering in the population density, the substrate heterogeneity may be a decisive factor in aggregation. Eight species of crustacean decapods and one bivalve species were identified as associated fauna.A ocorrência de M, guyanensis no estuário do Rio Paraíba do Norte foi mapeada, determinando-se sua presença ao longo dos afluentes e ilhas aí existentes. O estudo da dinâmica da população foi realizado em área protegida da Ilha da Restinga, coletando-se os animais ao longo de 37 transecções. A cada mês foram feitos 60 lançamentos com um delimitador de 0,1 m², sobre uma ou mais transecções. Todo o substrato foi retirado juntamente com os exemplares de M. guyanensis e a fauna associada, até a profundidade de 10 cm. A triagem dos exemplares menores foi feita por peneiramento do substrato. O tipo de substrato foi anotado a cada lançamento. Dois tipos de substrato estão presentes na área: um substrato de tipo consistente, constituido por 89.7% de silte e argila e 10.3% de areia fina e outro de tipo não consistente contendo 74.5% de silte e argila e 25.5% de areia fina. O substrato de tipo não consistente apresenta quantidade de água significativamente maior que o de tipo consistente. Mytella guyanensis vive enterrada no solo numa profundidade máxima de 1,0 cm, sempre envolvida pelos filamentos do bisso. A densidade média anual observada para a espécie foi de 5,2 indivíduos por m²; a distribuição espacial predominante foi do tipo agregado, sofrendo interferência do tipo de substrato presente. Houve preferência de fixação da espécie pelo substrato do tipo consistente. Animais entre 4,5 e 5,5 cm de comprimento ocorrem o ano todo, sendo mais numerosos aqueles com comprimento entre 4,5 e 5,0 cm. A presença de formas jovens foi assinalada em baixa frequência em alguns meses do ano. A salinidade da água estuarina variou de acordo com o regime pluviométrico da região, permanecendo dentro dos níveis de tolerância da espécie. A fauna associada está representada por oito espécies de crustáceos e por uma de molusco bivalve.

Threatened freshwater and terrestrial molluscs (Mollusca, Gastropoda et Bivalvia of Santa Catarina State, Southern Brazil: check list and evaluation of regional threats

Directory of Open Access Journals (Sweden)

2011-06-01

Full Text Available A total of nineteen continental native mollusc species are confirmed for the Santa Catarina State (SC(organized in ten Genera and seven Families, one aquatic Prosobranchia/Caenogastropoda (Ampullariidae,six Pulmonata terrestrial gastropods (one Ellobiidae, three Megalobulimidae and two micro-snails –Charopidae and Streptaxidae and twelve freshwater mussels (eight Mycetopodidae and four Hyriidae. Thesespecies are designated by the International Union for Conservation of the Nature – IUCN as follows: seven as"Vulnerable", six "In Danger" and six “Without Category Established”. The general regional threats that thesespecies are subjected to are briefly analyzed.

Intra-specific variability in life-history traits of Anadara tuberculosa (Mollusca: Bivalvia) in the mangrove ecosystem of the Southern coast of Ecuador.

Science.gov (United States)

Flores, Luis; Licandeo, Roberto; Cubillos, Luis A; Mora, Elba

2014-06-01

Anadara tuberculosa is one of the most important bivalves along the Western Pacific coast because of its commercial value. Nevertheless, the variability in growth, long-life span, natural mortality and reproductive parameters of this mangrove cockle has not yet been described. The aim of this study was to analyze these life-history traits in three areas of the Southern coast of Ecuador. Empirical and length-based methods were used to estimate these biological parameters. Body size data were collected from the commercial fishery between 2004 and 2011 in landing ports near to the Archipelago of Jambeli [Puerto Bolivar (PB), Puerto Jeli (PJ) and Puerto Hualtaco (PH)]. The von Bertalanffy growth parameters for combined sex were estimated between 70.87 to 93.45mm for L(infinity) and 0.22 to 0.80/year for k. The growth indices (PHI') ranged from 3.17 to 3.85, while the overall growth performance (OGP) ranged from 5.03 to 5.82. The mean of long-life span (t(max)), size and age at maturity (L50% and t50%) were estimated in 7.71 +/- 2.53 years, 39.13 +/- 2.24mm and 1.46 +/- 0.56 years for PB; 9.51 +/- 2.85 years, 37.78 +/- 1.95mm and 1.37 +/- 0.41 years for PJ and 5.81 +/- 2.11 years, 39.73 +/- 3.31mm and 0.94 +/- 0.41 years for PH. Natural mortality (M) ranged from 0.46 to 1.28/year. We concluded that significant intra-specific variation was observed in a temporal scale in PHI' and OGP indices as well as L50% and M. Therefore, temporal changes in these life-history traits should be taken into account when assessing the status of the mangrove cockle fishery.

Complexity explained

CERN Document Server

Erdi, Peter

2008-01-01

This book explains why complex systems research is important in understanding the structure, function and dynamics of complex natural and social phenomena. Readers will learn the basic concepts and methods of complex system research.

The wireless internet explained

CERN Document Server

Rhoton, John

2001-01-01

The Wireless Internet Explained covers the full spectrum of wireless technologies from a wide range of vendors, including initiatives by Microsoft and Compaq. The Wireless Internet Explained takes a practical look at wireless technology. Rhoton explains the concepts behind the physics, and provides an overview that clarifies the convoluted set of standards heaped together under the umbrella of wireless. It then expands on these technical foundations to give a panorama of the increasingly crowded landscape of wireless product offerings. When it comes to actual implementation the book gives abundant down-to-earth advice on topics ranging from the selection and deployment of mobile devices to the extremely sensitive subject of security.Written by an expert on Internet messaging, the author of Digital Press''s successful Programmer''s Guide to Internet Mail and X.400 and SMTP: Battle of the E-mail Protocols, The Wireless Internet Explained describes and evaluates the current state of the fast-growing and crucial...

Computer jargon explained

CERN Document Server

Enticknap, Nicholas

2014-01-01

Computer Jargon Explained is a feature in Computer Weekly publications that discusses 68 of the most commonly used technical computing terms. The book explains what the terms mean and why the terms are important to computer professionals. The text also discusses how the terms relate to the trends and developments that are driving the information technology industry. Computer jargon irritates non-computer people and in turn causes problems for computer people. The technology and the industry are changing so rapidly; it is very hard even for professionals to keep updated. Computer people do not

Megafauna of the UKSRL exploration contract area and eastern Clarion-Clipperton Zone in the Pacific Ocean: Annelida, Arthropoda, Bryozoa, Chordata, Ctenophora, Mollusca.

Science.gov (United States)

Amon, Diva J; Ziegler, Amanda F; Drazen, Jeffrey C; Grischenko, Andrei V; Leitner, Astrid B; Lindsay, Dhugal J; Voight, Janet R; Wicksten, Mary K; Young, Craig M; Smith, Craig R

2017-01-01

There is growing interest in mining polymetallic nodules from the abyssal Clarion-Clipperton Zone (CCZ) in the tropical Pacific Ocean. Despite having been the focus of environmental studies for decades, the benthic megafauna of the CCZ remain poorly known. To predict and manage the environmental impacts of mining in the CCZ, baseline knowledge of the megafauna is essential. The ABYSSLINE Project has conducted benthic biological baseline surveys in the UK Seabed Resources Ltd polymetallic-nodule exploration contract area (UK-1). Prior to ABYSSLINE research cruises in 2013 and 2015, no biological studies had been done in this area of the eastern CCZ. Using a Remotely Operated Vehicle and Autonomous Underwater Vehicle (as well as several other pieces of equipment), the megafauna within the UK Seabed Resources Ltd exploration contract area (UK-1) and at a site ~250 km east of the UK-1 area were surveyed, allowing us to make the first estimates of megafaunal morphospecies richness from the imagery collected. Here, we present an atlas of the abyssal annelid, arthropod, bryozoan, chordate, ctenophore and molluscan megafauna observed and collected during the ABYSSLINE cruises to the UK-1 polymetallic-nodule exploration contract area in the CCZ. There appear to be at least 55 distinct morphospecies (8 Annelida, 12 Arthropoda, 4 Bryozoa, 22 Chordata, 5 Ctenophora, and 4 Mollusca) identified mostly by morphology but also using molecular barcoding for a limited number of animals that were collected. This atlas will aid the synthesis of megafaunal presence/absence data collected by contractors, scientists and other stakeholders undertaking work in the CCZ, ultimately helping to decipher the biogeography of the megafauna in this threatened habitat.

Impact of zebra and quagga mussels (Dreissena spp.) on freshwater unionids (Bivalvia: Unionidae) in the Detroit River of the Great Lakes

Science.gov (United States)

Schloesser, D.W.; Kovalak, W.P.; Longton, G.D.; Ohnesorg, K.L.; Smithee, R.D.

1998-01-01

To assess the impact of zebra and quagga mussel (Dreissena spp.) infestation on unionids, unionids (Bivalvia: Unionidae) were sampled in the Detroit River in 1982-1983, before mussels invaded the river, and in 1992 and 1994, after mussels invaded the river. Live unionids at four stations along the southeastern shore accounted for 97% (20 species) of all shells collected in 1982-1983, whereas live unionids accounted for only 10% (13 species) in 1992. A similar decline in live unionids occurred at nine stations along the northwestern shore, except the decline occurred over the three sampling periods: in 1982-83, 84% (22 species) were live; in 1992, 65% (26 species) were live; and, in 1994, only 3% (13 species) were live. The difference in time to near-total mortality of unionids along the southeastern and northwestern shores is attributed to differences in the time of invasion and abundance of zebra mussel veligers in distinct water masses emanating from Lake St. Clair located immediately upstream of the Detroit River. Although individuals of all species of all unionid subfamilies declined between 1982 and 1992/1994, members of the subfamilies Anodontinae and Lampsilinae declined more than Ambleminae. Between 1986 and 1992/1994, five Anodontinae, three Lampsilinae and 0 Ambleminae species have been extirpated from the river due to dreissenid mussel infestation. Numbers of individuals of commonly found species declined more than numbers of individuals of uncommonly found species. However, the number of uncommon species declined 47% (17 to 9) along both the southeastern and northwestern shores, whereas common species remained the same (3 species) along the southeastern shore and declined only 40% (5 to 3 species) along the northwestern shore. This study, and others, suggest that high mortality of unionids can occur between 4 and 6 yr after initial invasion by dreissenids or up to 8 yr depending on water current patterns. Infestation-induced mortality of unionids in the

Population structure, biomass and production of the West African lucinid Keletistes rhizoecus (Bivalvia, Mollusca) in Sivibilagbara swamp at Bodo Creek, Niger Delta, Nigeria

NARCIS (Netherlands)

Zabbey, N.; Hart, A. I.; Wolff, W. J.

2010-01-01

The West African lucinid bivalve Keletistes rhizoecus (Oliver, Basteria 50:47-64, 1986) is only known from the Niger Delta in Nigeria. Due to inaccessibility of its habitat population biology, growth parameters, biomass, and annual secondary production are unknown. The danger of oil pollution

Analysis of trace elements in the shells of short-necked clam Ruditapes philippinarum (Mollusca: Bivalvia) with respect to reconstruction of individual life history

International Nuclear Information System (INIS)

Arakawa, Jumpei; Sakamoto, Wataru

1998-01-01

Strontium (Sr) concentration in the shells of short-necked clams collected at different locations (Shirahama, warm area and Maizuru, cold area, Japan) was analyzed by two methods, PIXE and EPMA. The Sr concentration of external surface of shell umbo, which was made during short term at early benthic phase, was analyzed by PIXE, and was ranged from 1000 to 3500 ppm for individuals. The Sr concentration of clams collected at Shirahama showed positive correlation with shell length (SL) in individuals with SL < 31 mm, whereas clams collected at Maizuru did not show significant correlation. This result may be caused from the difference of the spawning seasons between two areas. The Sr concentration of cross section of shell umbo, which develops thicker continuously during their life to form faint stratum structure, was analyzed by EPMA along the line across the stratum structure. Some surges and long term waving patterns of the Sr concentration were observed. These results suggest that the life histories of individual clams could be recorded in the shell umbo cross sections as variations of trace elements and analyses of trace elements could clarify the histories of individual clams. (author)

Reproduction and recruitment patterns of the surf clam Donax serra ...

African Journals Online (AJOL)

Reproduction and recruitment patterns of the surf clam Donax serra (Bivalvia, Donacidae) on two ... Keywords: condition index, Donax serra, histology, Namibia, recruitment, reproduction, sandy beach ecology ... AJOL African Journals Online.

Espécie invasora em unidade de conservação: Achatina fulica (Bowdich, 1822 no Parque Estadual Carlos Botelho, Sete Barras, SP, Brasil (Nota Científica. Invasive species in conservation unit: Achatina fulica (Bowdich, 1822 in Carlos Botelho State Park, Sete Barras, SP, Brazil (Scientific Note.

Directory of Open Access Journals (Sweden)

Marilda Rapp de ESTON

2006-12-01

Full Text Available O caramujo-gigante-africano, Achatinafulica (Mollusca-Achatinidae, considerado umadas cem piores espécies invasoras do mundo,causando sérios danos ambientais, é registrado pelaprimeira vez para o Parque Estadual CarlosBotelho, município de Sete Barras, Estado de SãoPaulo, Brasil.The Giant African Snail, Achatina fulica(Mollusca-Achatinidae, considered as one of ahundred worst world’s invasive species, causingserious environmental damages, is registered forthe first time for Carlos Botelho State Park, countyof Sete Barras, state of São Paulo, Brazil.

Ciclo gametogênico e comportamento reprodutivo de Iphigenia brasiliana (Mollusca, Bivalvia, Donacidae no estuário do rio Subaé, Baía de Todos os Santos, Bahia, Brasil Gametogenic cycle and reproductive behavior of Iphigenia brasiliana (Mollusca, Bivalvia, Donacidae in the Subaé river estuary, Todos os Santos Bay, Bahia, Brazil

Directory of Open Access Journals (Sweden)

Patrícia P. Silva

2012-12-01

Full Text Available Este estudo teve como objetivos descrever o ciclo gametogênico e o comportamento reprodutivo da população de Iphigenia brasiliana (Lamarck,1818 no estuário do rio Subaé, Baía de Todos os Santos, Bahia. Os bivalves foram coletados de novembro de 2001 a novembro de 2002. Um total de 244 espécimes foi medido (eixo anteroposterior, eviscerado, fixado, desidratado e incluído em parafina. O estudo histológico das gônadas foi realizado através de cortes seriados do tecido gonadal, de 5 mm de espessura, e corados pela HE. O tamanho médio mínimo da primeira maturação sexual (Lpm foi estimado a partir da distribuição das frequências relativas de jovens e adultos, por classe de comprimento dos indivíduos. As frequências relativas dos sexos em cada estádio de desenvolvimento foram consideradas conjuntamente para a análise do comportamento reprodutivo da população, e, em separado, para avaliar a sincronia do ciclo sexual entre machos e fêmeas. Foi observada uma variação de tamanhos entre 9,1 e 66,6 mm, com comprimento médio de 50,2 mm. O estudo não demonstrou diferença significativa entre os tamanhos de machos e fêmeas. Não foi possível observar a diferenciação de sexos em 2,1% dos indivíduos analisados. 51,6% dos indivíduos foram identificados como machos (M e 46,3% como fêmeas (F, não sendo constatadas diferenças significativas entre o número médio de machos e fêmeas, resultando numa proporção de M:F de 1,1:1. O Lpm foi estimado em 11,4 mm, mas apenas ao alcançarem comprimento médio de 34,4 mm, todos os indivíduos foram considerados adultos. Foram caracterizados quatro estádios de evolução do desenvolvimento gonadal em fêmeas e machos. A análise dos diferentes estádios permitiu a observação dos fenômenos de atresia e inversão sexual em fêmeas. O ciclo reprodutivo apresentou eliminação contínua de gametas, com maiores intensidades reprodutivas nos meses de novembro de 2001 a abril de 2002 e, também, no mês de outubro de 2002.This study aimed to describe the gametogenic cycle and reproductive behavior of the population of Iphigenia brasiliana (Lamarck, 1818 in the estuary of the Subaé river, Todos os Santos Bay, Bahia. The bivalves were collected from November 2001 to November 2002. A total of 244 specimens was measured (anteroposterior axis, gutted, fixed, dehydrated and embedded in paraffin. The histology of the gonads was performed by 5 mm thick serial sections of gonadal tissue, and stained with HE. The length at the beginning of gonadal maturation (Lpm was estimated from the distribution of the relative frequencies of youth and adults, by length class of individuals. The relative frequencies of the sexes at each stage of development were considered together for the analysis of the reproductive behavior of the population, and, separately, to assess the sexual cycle synchrony between males and females. We observed a variation of sizes between 9.1 and 66.6 mm, with a mean length of 50.2 mm. The study showed no significant difference between the sizes of males and females. There was no evidence of gender differentiation in 2.1% of subjects analyzed. 51.6% of subjects were identified as males (M and 46.3% as females (F, without significant differences among average number of male and female, resulting in the proportion of M:F ratio of 1,1:1. Lpm was estimated at 11.4 mm, but only to achieve average length of 34.4 mm, all subjects were considered adults. We characterized four stages of evolution of gonadal development in females and males. Analysis of different stages allowed the observation of the atresia phenomena and sex reversal in females. The reproductive cycle presents continuous elimination of gametes, with higher reproductive intensities in the months of November 2001 to April 2002 and also in October 2002.

Ciclo gametogênico e comportamento reprodutivo de Iphigenia brasiliana (Mollusca, Bivalvia, Donacidae no estuário do rio Subaé, Baía de Todos os Santos, Bahia, Brasil Gametogenic cycle and reproductive behavior of Iphigenia brasiliana (Mollusca, Bivalvia, Donacidae in the Subaé river estuary, Todos os Santos Bay, Bahia, Brazil

Directory of Open Access Journals (Sweden)

Patrícia P. Silva

2012-01-01

Full Text Available Este estudo teve como objetivos descrever o ciclo gametogênico e o comportamento reprodutivo da população de Iphigenia brasiliana (Lamarck,1818 no estuário do rio Subaé, Baía de Todos os Santos, Bahia. Os bivalves foram coletados de novembro de 2001 a novembro de 2002. Um total de 244 espécimes foi medido (eixo anteroposterior, eviscerado, fixado, desidratado e incluído em parafina. O estudo histológico das gônadas foi realizado através de cortes seriados do tecido gonadal, de 5 mm de espessura, e corados pela HE. O tamanho médio mínimo da primeira maturação sexual (Lpm foi estimado a partir da distribuição das frequências relativas de jovens e adultos, por classe de comprimento dos indivíduos. As frequências relativas dos sexos em cada estádio de desenvolvimento foram consideradas conjuntamente para a análise do comportamento reprodutivo da população, e, em separado, para avaliar a sincronia do ciclo sexual entre machos e fêmeas. Foi observada uma variação de tamanhos entre 9,1 e 66,6 mm, com comprimento médio de 50,2 mm. O estudo não demonstrou diferença significativa entre os tamanhos de machos e fêmeas. Não foi possível observar a diferenciação de sexos em 2,1% dos indivíduos analisados. 51,6% dos indivíduos foram identificados como machos (M e 46,3% como fêmeas (F, não sendo constatadas diferenças significativas entre o número médio de machos e fêmeas, resultando numa proporção de M:F de 1,1:1. O Lpm foi estimado em 11,4 mm, mas apenas ao alcançarem comprimento médio de 34,4 mm, todos os indivíduos foram considerados adultos. Foram caracterizados quatro estádios de evolução do desenvolvimento gonadal em fêmeas e machos. A análise dos diferentes estádios permitiu a observação dos fenômenos de atresia e inversão sexual em fêmeas. O ciclo reprodutivo apresentou eliminação contínua de gametas, com maiores intensidades reprodutivas nos meses de novembro de 2001 a abril de 2002 e, também, no mês de outubro de 2002.This study aimed to describe the gametogenic cycle and reproductive behavior of the population of Iphigenia brasiliana (Lamarck, 1818 in the estuary of the Subaé river, Todos os Santos Bay, Bahia. The bivalves were collected from November 2001 to November 2002. A total of 244 specimens was measured (anteroposterior axis, gutted, fixed, dehydrated and embedded in paraffin. The histology of the gonads was performed by 5 mm thick serial sections of gonadal tissue, and stained with HE. The length at the beginning of gonadal maturation (Lpm was estimated from the distribution of the relative frequencies of youth and adults, by length class of individuals. The relative frequencies of the sexes at each stage of development were considered together for the analysis of the reproductive behavior of the population, and, separately, to assess the sexual cycle synchrony between males and females. We observed a variation of sizes between 9.1 and 66.6 mm, with a mean length of 50.2 mm. The study showed no significant difference between the sizes of males and females. There was no evidence of gender differentiation in 2.1% of subjects analyzed. 51.6% of subjects were identified as males (M and 46.3% as females (F, without significant differences among average number of male and female, resulting in the proportion of M:F ratio of 1,1:1. Lpm was estimated at 11.4 mm, but only to achieve average length of 34.4 mm, all subjects were considered adults. We characterized four stages of evolution of gonadal development in females and males. Analysis of different stages allowed the observation of the atresia phenomena and sex reversal in females. The reproductive cycle presents continuous elimination of gametes, with higher reproductive intensities in the months of November 2001 to April 2002 and also in October 2002.

Propensity to metal accumulation and oxidative stress responses of two benthic species (Cerastoderma edule and Nephtys hombergii): are tolerance processes limiting their responsiveness?

KAUST Repository

Marques, Ana; Piló , David; Araú jo, Olinda; Pereira, Fá bio; Guilherme, Sofia; Carvalho, Susana; Santos, Maria Ana; Pacheco, Má rio; Pereira, Patrí cia

2016-01-01

and antioxidant system responses of two benthic organisms (Cerastoderma edule, Bivalvia; Nephtys hombergii, Polychaeta). This approach will provide clarifications about the ability of each species to signalise metal contamination. Organisms of both species were

African Journal of Marine Science - Vol 23 (2001)

African Journals Online (AJOL)

... in the Benguela upwelling system and Angola-Benguela front using an artificial ... Reproduction and recruitment patterns of the surf clam Donax serra (Bivalvia, ... Variable spatial structure of schooling pelagic fish off Namibia: implications ...

On the role of water and forage in penetration of some radionuclides into the Limnaea organism

International Nuclear Information System (INIS)

Marchyulenene, D.P.; Polikarpov, G.G.; AN Ukrainskoj SSR, Sevastopol. Inst. Biologii Yuzhnykh Morej)

1976-01-01

The objective of this work was to study under laboratory conditions the significance of elodea (Elodea canadensis Rich.) and aqueous medium in accumulation of strontium-90, cesium-137, cerium-144 and ruthenium-106 by limnetic gastropods (Limnaea Stagnalis L.). The study revealed that only 2 and 5% of strontium-90 and cerium-144 respectively were accumulated in molluscs shell from radioactive food, and 4 and 26% - in the body. The authors believed that higher accumulation levels of cerium-144 and ruthenium-106 in mollusca body when the molluscs are fed with radioactive elodea were caused by high accumulation coefficients (AC) of radionuclides in food, i.e. elodea, and their accumulation in the gastrointestinal tracts of molluscs. To appreciates the significance of elodea and water as sources of radionuclide accumulation by mollusca, strontium-90 and cerium-144 AC in molluscs were estimated in relation to water and elodea. The results obtained indicated that AC of these radionuclides in mollusca was much lower in relation to food than to water

Self-explaining roads

NARCIS (Netherlands)

Horst, A.R.A. van der; Kaptein, N.

1999-01-01

As a means to a sustainable safe traffic environment the concept of Self-Explaining Roads (SER) has been developed. The SER concept advocates a traffic environment that elicits safe driving behaviour simply by its design. In order to support safe driving behaviour and appropriate speed choice,

Population distribution of meiofauna in relation to some environmental features in a sandy intertidal region of Goa, west coast of India

Digital Repository Service at National Institute of Oceanography (India)

Harkantra, S.N.; Parulekar, A.H.

Meiofauna population of Candolim beach mainly composed of nematoda (40.15), harpacticoida (30.75 per cent), turbellaria (23.35 per cent) and other groups which included polychaeta, bivalvia and mystacocardia. The maximum total meiofauna population...

Reproductive activity and biochemical composition of the pullet carpet shell Venerupis senegalensis (Gmelin, 1791 (Mollusca: Bivalvia from Ria de Aveiro (northwestern coast of Portugal

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Sandra Joaquim

2011-06-01

Full Text Available The present study characterizes the reproductive cycle of Venerupis senegalensis (=V. pullastra from Ria de Aveiro (Portugal as well as its nutrient storage and exploitation strategy. The reproductive cycle followed a seasonal cycle that correlated negatively with sea surface temperature, and comprised a ripe stage in winter followed by a spawning period that began in late winter and ended in the early summer. This extended spawning may be an advantageous strategy for the species because it ensures a continuous supply of settlers. Gametogenesis began in late summer/early autumn and intensified with the decrease in temperature during autumn. The condition index increased even during the spawning period, which indicates that there is rapid recovery and that reserves are accumulated during late summer and used later in the gametogenic process. Proteins did not contribute significantly to gametogenesis and the glycogen pattern is typical of conservative species, since gametogenesis depends largely on the amount of glycogen stored. The lipid storage and utilization cycle showed that gametogenesis took place in autumn/winter and that energy reserves were accumulated in summer.

Evaluation of magnesium and manganese in Perna perna mussels (Linnaeus, 1758: mollusca, bivalvia) collected in the cost of the state of Sao Paulo, Brazil

Energy Technology Data Exchange (ETDEWEB)

Seo, Daniele; Vasconcellos, Marina B.A.; Saiki, Mitiko; Cathartino, Marilia G.M.; Moreira, Edson G., E-mail: mbvascon@ipen.b, E-mail: mitiko@ipen.b, E-mail: emoreira@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Sousa, Eduinetty C.P.M. de, E-mail: edvinett@usp.b [Universidade de Sao Paulo (IO/USP), SP (Brazil). Inst. Oceanografico. Lab. de Ecotoxicologia Marinha e Microfitobentos

2011-07-01

The objective of the present study was to evaluate magnesium and manganese concentrations in Perna perna mussels by applying instrumental neutron activation analysis (INAA). The mussels were collected seasonally from September 2008 to July 2009 at Cocanha Beach in the city of Caraguatatuba (clean region), and at two sites in Santos Bay (Ponta de Itaipu and Palmas Island). The mussel samples were cleaned, grinded, homogenized, lyophilized and then analyzed by INAA. The INAA procedure consisted in the irradiation of the samples and synthetic elemental standards for 10 s, under a thermal neutron flux of 6.6 x 10{sup 12} n cm{sup -2} s{sup -1} in the nuclear research reactor of IPEN-CNEN/SP. The measurements of the gamma radioactivity of the samples and standards were carried out using a hyperpure semiconductor Ge detector, coupled to Digital Spectral Analyzer. The elemental concentrations were calculated by the comparative method. For quality control of analytical results, certified reference materials NIST SRM 1566b oyster tissue and NRC DORM-2 Dogfish Muscle were analyzed and their results indicated good accuracy. The element concentrations in mussels on dry mass basis varied from 2734 {+-} 205 to 5138 {+-} 507 mg kg{sup -1} for Mg and from 7.35{+-}0.57 to 29.06{+-}3.35 mg kg{sup -1} for Mn. The results obtained in mussel analysis indicated that the samples collected in Itaipu in the winter season presented higher accumulation of Mg than the other sites. For Mn, the highest concentrations were obtained for the mussels collected in Palmas in summer time. (author)

Evaluation of magnesium and manganese in Perna perna mussels (Linnaeus, 1758: mollusca, bivalvia) collected in the cost of the state of Sao Paulo, Brazil

International Nuclear Information System (INIS)

Seo, Daniele; Vasconcellos, Marina B.A.; Saiki, Mitiko; Cathartino, Marilia G.M.; Moreira, Edson G.; Sousa, Eduinetty C.P.M. de

2011-01-01

The objective of the present study was to evaluate magnesium and manganese concentrations in Perna perna mussels by applying instrumental neutron activation analysis (INAA). The mussels were collected seasonally from September 2008 to July 2009 at Cocanha Beach in the city of Caraguatatuba (clean region), and at two sites in Santos Bay (Ponta de Itaipu and Palmas Island). The mussel samples were cleaned, grinded, homogenized, lyophilized and then analyzed by INAA. The INAA procedure consisted in the irradiation of the samples and synthetic elemental standards for 10 s, under a thermal neutron flux of 6.6 x 10 12 n cm -2 s -1 in the nuclear research reactor of IPEN-CNEN/SP. The measurements of the gamma radioactivity of the samples and standards were carried out using a hyperpure semiconductor Ge detector, coupled to Digital Spectral Analyzer. The elemental concentrations were calculated by the comparative method. For quality control of analytical results, certified reference materials NIST SRM 1566b oyster tissue and NRC DORM-2 Dogfish Muscle were analyzed and their results indicated good accuracy. The element concentrations in mussels on dry mass basis varied from 2734 ± 205 to 5138 ± 507 mg kg -1 for Mg and from 7.35±0.57 to 29.06±3.35 mg kg -1 for Mn. The results obtained in mussel analysis indicated that the samples collected in Itaipu in the winter season presented higher accumulation of Mg than the other sites. For Mn, the highest concentrations were obtained for the mussels collected in Palmas in summer time. (author)

Pleurolucina from the western Atlantic and eastern Pacific Oceans: a new intertidal species from Curaçao with unusual shell microstructure (Mollusca, Bivalvia, Lucinidae

Directory of Open Access Journals (Sweden)

Emily A. Glover

2016-09-01

Full Text Available A new shallow water species of the lucinid bivalve Pleurolucina is described from Curaçao in the southern Caribbean Sea and compared with known species of the genus from the western Atlantic and eastern Pacific Oceans. Although confused with the Floridian species P. leucocyma, it is most similar to the eastern Pacific P. undata. As in all studied lucinids, the new species possesses symbiotic bacteria housed in the ctenidia. The shell microstructure is unusual with repeated and intercalated conchiolin layers that have sublayers of ‘tulip-shaped’ calcareous spherules. Predatory drillings by naticid gastropods frequently terminate at the conchiolin layers.

Taxocenosis of mollusks and crustaceans on roots of Rhizophora mangle (Rhizophoraceae at Cispatá Bay, Córdoba, Colombia

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Jorge Alexander Quirós R

2013-05-01

EN LA BAHÍA DE CISPATÁ, CÓRDOBA, COLOMBIA A pesar del conocimiento existente sobre la ecología de los manglares en la bahía de Cispatá, pocos estudios han sido enfocados en invertebrados asociados a las raíces del mangle rojo. Entre diciembre 2010 y septiembre 2011, se evaluó la estructura de los ensamblajes de moluscos y crustáceos asociados a las raíces de Rhizophora mangle en dos sectores de muestreo de la bahía de Cispatá, Colombia. Para la recolección del material biológico se tomaron al azar tres raíces de mangle homogéneas en cuanto al diámetro. Los organismos fueron obtenidos de la raíz raspando la superficie con un cuchillo, luego fueron separados y fijados en formalina al 10% para su posterior identificación. De los 12289 individuos recolectados en los cuatro muestreos, 10470 pertenecieron al phylum Mollusca (85,2% y los restantes 1819 al subphylum Crustacea (14,8%. Para los moluscos se identificaron 14 especies distribuidas en 12 familias y dos clases; Bivalvia y Gastropoda. Para los crustáceos se identificaron 24 especies distribuidas en 16 familias y cuatro órdenes; Sessillia, Decapoda, Isopoda y Amphipoda. En los dos sectores de muestreo Mytella charruana, Balanus eburneus y Crassostrea rhizophorae fueron las especies más importantes en términos de abundancia, no obstante M. charruana y B. eburneus presentan una gran capacidad de adaptación y ajuste a las variaciones hidroclimáticas, mostrándose como especies fuertemente eurihalinas, lo que se relejó en la dominancia de dichas especies en el sector B. La presencia de Petrolisthes armatus y Aratus pisonii indica que son especies de bosques de manglar con gran movilidad y mecanismos de adaptación fisiológicos, lo que justifica su presencia en el sector A.

Gaining from explaining: Learning improves from explaining to fictitious others on video, not from writing to them

NARCIS (Netherlands)

Hoogerheide, Vincent; Deijkers, Lian; Loyens, Sofie M M; Heijltjes, Anita; van Gog, Tamara

2016-01-01

Two experiments investigated whether studying a text with an "explanation intention" and then actually explaining it to (fictitious) other students in writing, would yield the same benefits as previously found for explaining on video. Experiment 1 had participants first studying a text either with

Explaining the Gender Wealth Gap

Science.gov (United States)

Ruel, Erin; Hauser, Robert M.

2013-01-01

To assess and explain the United States’ gender wealth gap, we use the Wisconsin Longitudinal Study to examine wealth accumulated by a single cohort over 50 years by gender, by marital status, and limited to the respondents who are their family’s best financial reporters. We find large gender wealth gaps between currently married men and women, and never-married men and women. The never-married accumulate less wealth than the currently married, and there is a marital disruption cost to wealth accumulation. The status-attainment model shows the most power in explaining gender wealth gaps between these groups explaining about one-third to one-half of the gap, followed by the human-capital explanation. In other words, a lifetime of lower earnings for women translates into greatly reduced wealth accumulation. A gender wealth gap remains between married men and women after controlling for the full model that we speculate may be related to gender differences in investment strategies and selection effects. PMID:23264038

Pursuing the quest for better understanding the taxonomic distribution of the system of doubly uniparental inheritance of mtDNA

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Arthur Gusman

2016-12-01

Full Text Available There is only one exception to strict maternal inheritance of mitochondrial DNA (mtDNA in the animal kingdom: a system named doubly uniparental inheritance (DUI, which is found in several bivalve species. Why and how such a radically different system of mitochondrial transmission evolved in bivalve remains obscure. Obtaining a more complete taxonomic distribution of DUI in the Bivalvia may help to better understand its origin and function. In this study we provide evidence for the presence of sex-linked heteroplasmy (thus the possible presence of DUI in two bivalve species, i.e., the nuculanoid Yoldia hyperborea(Gould, 1841and the veneroid Scrobicularia plana(Da Costa,1778, increasing the number of families in which DUI has been found by two. An update on the taxonomic distribution of DUI in the Bivalvia is also presented.

SPSS explained

CERN Document Server

Hinton, Perry R; Brownlow, Charlotte

2014-01-01

SPSS Explained provides the student with all that they need to undertake statistical analysis using SPSS. It combines a step-by-step approach to each procedure with easy to follow screenshots at each stage of the process. A number of other helpful features are provided: regular advice boxes with tips specific to each test explanations divided into 'essential' and 'advanced' sections to suit readers at different levels frequently asked questions at the end of each chapter. The first edition of this popular book has been fully updated for IBM SPSS version 21 and also includes: chapters that expl

Tolerance to air exposure of the New Zealand mudsnail Potamopyrgus antipodarum (Hydrobiidae, Mollusca as a prerequisite to survival in overland translocations

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Alvaro Alonso

2012-08-01

Full Text Available Spreading throughout a new ecosystem is the last step of an exotic species to become invasive. In the case of invasive aquatic molluscs, tolerance to air exposure is one of the main mechanisms allowing overland translocation and spreading. The mudsnail Potamopyrgus antipodarum (Hydrobiidae, Mollusca is native to New Zealand but it has spread worldwide, invading ecosystems in Europe, Australia, America and Asia. The aim of our study is to assess mudsnail tolerance to air exposure, which may contribute to the successful overland translocation of this species. We conducted a laboratory experiment with four levels of air exposure (9, 18, 24 and 36 hours in a controlled climatic chamber. Snails were placed for 60 seconds in a laboratory paper filter to remove surface snail water. Then they were placed back in empty vessels during the four periods of air exposure, except the control group, which was immediately returned to water. At the end of each period of air exposure all vessels were filled with water and the cumulative mortality was monitored after 24, 96, 168 and 264 hours of rehydration. The calculated Lethal Times (i.e. the time of air exposure (in hours necessary to cause the death of 50% (LT50 or 99% (LT99 of the population and their 95% confidence limits at 24, 96, 168 and 264 hours were 28.1 (25.2–31.9, 26.9 (24.2–30.1, 25.9 (23.4–28.9 and 25.9 (23.4–28.9 hours, respectively for LT50, and 49.6 (42.7–63.3, 45.6 (39.9–56.5, 43.2 (38.0–53.0 and 43.2 (38.0–53.0 hours, respectively for LT99. Therefore an air exposure time over 43 hours caused the death of all studied individuals during all monitoring periods. Extending the monitoring period beyond 24 hours did not significantly change lethal times. Therefore, we recommend exposing fishing tools or boats at open air during at least 53 hours as a low cost measure to control mudsnail spread in early stages of invasion.

Long-term dynamics of the state of the fouling community in the Odessa Bay (Black Sea

Directory of Open Access Journals (Sweden)

A. Y. Varigin

2017-04-01

Full Text Available This article examines the long-term dynamics of the qualitative and quantitative characteristics of the coastal fouling community of OdessaBay(Black Sea for the last 40 years. It compares the data on this community obtained by different researchers in 1976, 1994 and 2016 . The number of species included in the fouling community decreased from 103 (1976 to 43 (1994 and then rose to 62 by 2016. As a possible reason for this reduction in the species composition of the community the influence of large-scale anthropogenic eutrophication, which was already strongly evident in the north-western part of the Black Seain the 1970s, is proposed. This phenomenon was accompanied by periodic outbreaks of mass abundance of planktonic algae, secondary water pollution, the development of hypoxia and a frequent suffocation effect on the benthos, which caused the disappearance from the community of 41 species of invertebrates. The reduction in the number of species affected representatives of the following taxons: Polychaeta, Amphipoda, Gastropoda and Bivalvia. Currently, the core of the community includes the same species of invertebrates as in the past. It is based on Bivalvia mussels Mytilus galloprovincialis. Among the attached forms , Mytilaster lineatus (Bivalvia and Amphibalanus improvisus (Cirripedia play a leading role, and among mobile – representatives of Polychaeta, Isopoda, Amphipoda and Gastropoda. It is shown that 10 of the 25 species, recorded the first time for this community in the 1970s, have become abundant in modern conditions. The primacy in the relative density in the composition of the community at the present time has passed from the amphipod crustaceans to bivalve molluscs. The highest relative biomass, both in the past and in the present-day conditions was observed in representatives of Bivalvia. The structure of the resistance of the fouling community to the effects of unstable environmental factors specific to the coastal zone is

Molecular resolution of the family Dreissenidae (Mollusca: Bivalvia) with emphasis on Ponto-Caspian species, including first report of Mytilopsis leucophaeata in the Black Sea basin.

Science.gov (United States)

Therriault, Thomas W; Docker, Margaret F; Orlova, Marina I; Heath, Daniel D; MacIsaac, Hugh J

2004-03-01

Considerable uncertainty exists in determination of the phylogeny among extant members of the Dreissenidae, especially those inhabiting the Ponto-Caspian basin, as multiple systematic revisions based on morphological characteristics have failed to resolve relationships within this group of bivalves. In this study we use DNA sequence analyses of two mitochondrial gene fragments, 16S rRNA and cytochrome c oxidase subunit I (COI), to determine phylogenetic relationships among Dreissena rostriformis, D. bugensis, D. polymorpha, D. stankovici, Congeria kusceri, and Mytilopsis leucophaeata. Dreissena stankovici was determined to represent a sister taxa to D. polymorpha and both are more closely related to other extant Dreissena species than Congeria or Mytilopsis. Sequence divergence between D. rostriformis and D. bugensis was relatively low (0.3-0.4%), suggesting that these two taxa constitute a single species. However, environmental differences suggest two races of D. rostriformis, a brackish water race (rostriformis) and a freshwater race (bugensis). Spread of bugensis-type individuals into habitats in the Caspian Sea that are occupied by rostriformis-type individuals may create novel hybridization opportunities. Species-specific molecular markers also were developed in this study since significant intraspecific variation in morphological features complicates dreissenid identification. Using two gene fragments (nuclear 28S and 16S), we identified restriction fragment length polymorphisms (RFLPs) that distinguish among D. rostriformis/bugensis, D. polymorpha, and D. stankovici and revealed the presence of a cryptic invader to the Black Sea basin, Mytilopsis leucophaeata. This is the first report of this North American native in southern Europe.

[Lipid and fatty acid profile of Perna viridis, green mussel (Mollusca: Bivalvia) in different areas of the Eastern Venezuela and the West Coast of Trinidad].

Science.gov (United States)

Koftayan, Tamar; Milano, Jahiro; D'Armas, Haydelba; Salazar, Gabriel

2011-03-01

The species Perna viridis is a highly consumed species, which fast growth makes it an interesting aquaculture alternative for Venezuelan and Trinidad coasts. With the aim to contribute with its nutritional value information, this study analyzed lipid and fatty acid contents from samples taken in five locations from Eastern Venezuela and three from Trinidad West Coast. Total lipids were extracted and quantified, from a pooled sample of 100 organisms per location, by standard gravimetric methods, and their identification and quantification was done by TLC/FID (Iatroscan system). Furthermore, the esterified fatty acids of total lipid, phospholipids and triacylglycerols were identified and quantified by gas chromatography. Eastern Venezuela samples from Los Cedros, La Brea and Chaguaramas showed the highest total lipid values of 7.92, 7.74 and 7.53, respectively, and the minimum values were obtained for La Restinga (6.08%). Among lipid composition, Chacopata samples showed the lowest phospholipid concentration (48.86%) and the maximum values for cholesterol (38.87%) and triacylglycerols (12.26%); besides, La Esmeralda and Rio Caribe samples exhibited maximum phospholipids (88.71 and 84.93 respectively) and minimum cholesterol (6.50 and 4.42%) concentrations. Saturated fatty acids represented between 15.04% and 65.55% within total lipid extracts, with maximum and minimum values for La Esmeralda and Chacopata, respectively. Polyunsaturated results resulted between 7.80 and 37.18%, with higher values in La Brea and lower values in La Esmeralda. For phospholipids, saturated fatty acids concentrations varied between 38.81 and 48.68% for Chaguaramas and Chacopata samples, respectively. In the case of polyunsaturated fatty acids, these varied between non detected and 34.51%, with high concentrations in Los Cedros (27.97%) and Chaguaramas (34.51%) samples. For the triacylglycerols, the saturated fatty acids composition oscillated between 14.27 and 53.80% with low concentrations for Chacopata and high concentration for La Restinga; the polyunsaturated fatty acids were between 4.66 and 35.55% with lower values for Chacopata and higher values for Chaguaramas samples. P. viridis is recommended for human being consumption, according to the high content of unsaturated fatty acids found for this species.

MAGMADIM: Young Explainers Program

International Nuclear Information System (INIS)

Paltiel, Z.

2005-01-01

Full Text:Physics teachers and educators constantly face the problem of inspiring their students to major in physics. On the other hand, science museums are designed to provide a pleasant environment which will stimulate and encourage a science associated experience to the general public. Typically, there is no intention to teach science as such in science museums. One may, however, use the science museum to teach and inspire certain groups of students in a much deeper sense. In fact they may actually enthusiastically learn much of the school physics curriculum at the museum. This report discusses the Magmadim program through which 10th graders are trained to be young explainers at the Weizmann Institutes Clore Garden of Science. To this end they study the physics underlying its exhibits in an after-school course. The ultimate goal is for the 'magmadim' to become the best possible explainers and be able to face all sorts of museum visitors. Along with learning how to instruct visitors, they must learn the physics behind the exhibits to give a full explanation of the exhibit and be able to answer any question that may arise. Our 5 year experience with the program shows that its self-selected participants not only study a lot of science, but also like it and learn how to explain the content to other people. This program, along with similar programs at the Bloomfield Science Museum and the Madatzim (young physics tutors) program of Ort, help in promoting the interest in science in general and physics in particular among school students. Various ways to expand the programs will also be discussed

Malacología Latinoamericana: Moluscos de agua dulce de Argentina

Directory of Open Access Journals (Sweden)

Alejandra Rumi

2008-03-01

Full Text Available Se presenta un estado de situación y una lista actualizada y comentada sobre las especies de moluscos de agua dulce de la República Argentina. Se aborda en Gastropoda y Bivalvia la distribución a nivel de familias; las entidades endémicas, exóticas, invasoras y de importancia sanitaria. Los moluscos relacionados a la cuenca del Plata presentan la mayor riqueza específica. Base de datos: 4 500 registros relevados de las tres colecciones más importantes de la Argentina: MLP, MACN y FML. Además, se incluye información de recolecciones actuales y localidades citadas por otros autores. Hasta el presente han sido descritas 166 especies. De ellas 101 pertenecen a 10 familias de Gastropoda y 65 a 7 de Bivalvia. Las familias que presentan mayor riqueza específica son Lithoglyphidae (22 y Sphaeriidae (25, respectivamente. Sphaeriidae, Cochliopidae, Chilinidae y Lymnaeidae se distribuyen prácticamente en todo el país. Erodonidae y Solecurtidae se registran en ambientes mixohalinos de la provincia de Buenos Aires. Thiaridae y Glacidorbiidae presentan una distribución muy restringida. Especies endémicas de la Argentina: Gastropoda: Ampullariidae (1, Cochliopidae (10, Lithoglyphidae (11, Thiariidae (3, Chilinidae (11, Lymnaeidae (2 y Physidae (2?; Bivalvia: Hyriidae (1?; Etheriidae (1? y Sphaeriidae (10. Especies de interés sanitario: propagadoras de: Esquistosomiasis, Biomphalaria peregrina, B. straminea y B. tenagophila (Planorbidae; Fasciolasis, Lymnaea viatrix y L. columnella (Lymnaeidae; y dermatitis esquistosómicas, Chilina gibbosa y C. fluminea (Chilinidae. Especies de origen asiático: Corbicula fluminea (Corbiculidae y Limnoperna fortunei (Mytilidae. Es prioritaria la formación de áreas protegidas para la conservación de especies endémicas, especialmente de la Mesopotamia Argentina.Latin American Malacology. Freshwater Mollusks from Argentina. A report and an updated list with comments on the species of freshwater molluscs of

Do you get it? User-evaluated explainable BDI agents

NARCIS (Netherlands)

Broekens, J.; Harbers, M.; Hindriks, K.; Bosch, K. van den; Jonker, C.; Meyer, J.J.C.

2010-01-01

In this paper we focus on explaining to humans the behavior of autonomous agents, i.e., explainable agents. Explainable agents are useful for many reasons including scenario-based training (e.g. disaster training), tutor and pedagogical systems, agent development and debugging, gaming, and

Thermally-assisted Magma Emplacement Explains Restless Calderas.

Science.gov (United States)

Amoruso, Antonella; Crescentini, Luca; D'Antonio, Massimo; Acocella, Valerio

2017-08-11

Many calderas show repeated unrest over centuries. Though probably induced by magma, this unique behaviour is not understood and its dynamics remains elusive. To better understand these restless calderas, we interpret deformation data and build thermal models of Campi Flegrei caldera, Italy. Campi Flegrei experienced at least 4 major unrest episodes in the last decades. Our results indicate that the inflation and deflation of magmatic sources at the same location explain most deformation, at least since the build-up of the last 1538 AD eruption. However, such a repeated magma emplacement requires a persistently hot crust. Our thermal models show that this repeated emplacement was assisted by the thermal anomaly created by magma that was intruded at shallow depth ~3 ka before the last eruption. This may explain the persistence of the magmatic sources promoting the restless behaviour of the Campi Flegrei caldera; moreover, it explains the crystallization, re-melting and mixing among compositionally distinct magmas recorded in young volcanic rocks. Our model of thermally-assisted unrest may have a wider applicability, possibly explaining also the dynamics of other restless calderas.

The association between invertebrates and macrophytes in a ...

African Journals Online (AJOL)

The invertebrate fauna associated with aquatic macrophytes in the littoral of Lake Kariba was studied over a three-month period in 2002. Animals from seven classes — Hirudinea, Oligochaeta, Turbellaria, Insecta, Crustacea, Bivalvia and Gastropoda — were collected. Two hirudineans, Placobdella sp. and Haemopsis sp., ...

Can inflation explain the second law of thermodynamics

International Nuclear Information System (INIS)

Page, D.N.; Pennsylvania State Univ., University Park

1984-01-01

The inflationary model of the universe can explain several of the cosmological conundra that are mysteries in the standard hot big bang model. Paul Davies has suggested that inflation can also explain the second law of thermodynamics, which describes the time asymmetry of the universe. Here several difficulties with this suggestion are noted showing how the present inflationary models must assume the arrow of time rather than explaining it. If the second law is formulated as a consequence of the hypothesis that there were no long-range spatial correlations in the initial state of the universe, it is shown how some of the cosmological conundra might be explained even without inflation. But if the ultimate explanation is to include inflation, three essential elements remain to be demonstrated which are listed. (author)

The feeding ecology of Aphanius fasciatus (Valenciennes, 1821 in the lagoonal system of Messolongi (western Greece

Directory of Open Access Journals (Sweden)

Ioannis Leonardos

2008-06-01

Full Text Available The Mediterranean toothcarp Aphanius fasciatus (Valenciennes, 1821 is a small-sized omnivorous estuarine fish. Its diet is dominated by juveniles of shrimps (Palaemon adspersus, Isopods, Branchiopoda, Bivalvia, eggs of invertebrates, mosquitoes (adults and larvae and diatoms. An ontogenetic diet shift with an increase in mean prey size with fish length was observed. Smaller fish feed on planktonic prey (e.g. copepods, ostracods, nauplii of Artemia, while larger fish prefer larger and more benthic preys (e.g. ampipods, Bivalvia. The diet of A. fasciatus shows a high degree of seasonal variation, with a reduction in the feeding activity during the periods of adverse environmental conditions (winter and autumn. It is a well-adapted estuarine fish, its feeding mode and preferences depending on the preys that are available. Its feeding strategy is characterised by specialisation in different resource types (aquatic invertebrates and mosquitoes and a high between-phenotype contribution (BPC to niche width, with specialised individuals showing little or no overlap in resource use.

Your Radiologist Explains Nuclear Medicine

Medline Plus

Full Text Available ... Disorders Video: The Basketball Game: An MRI Story Radiology and You Sponsored by Image/Video Gallery Your Radiologist Explains Nuclear Medicine Transcript Welcome to Radiology Info dot org Hello! I’m Dr. Ramji ...

Your Radiologist Explains Nuclear Medicine

Medline Plus

Full Text Available ... by Image/Video Gallery Your Radiologist Explains Nuclear Medicine Transcript Welcome to Radiology Info dot org Hello! ... d like to talk to you about nuclear medicine. Nuclear medicine offers the potential to identify disease ...

Your Radiologist Explains Nuclear Medicine

Medline Plus

Full Text Available ... An MRI Story Radiology and You Sponsored by Image/Video Gallery Your Radiologist Explains Nuclear Medicine Transcript ... by a special camera and computer to create images of the inside of your body. If you’ ...

Your Radiologist Explains Nuclear Medicine

Medline Plus

Full Text Available ... Sponsored by Image/Video Gallery Your Radiologist Explains Nuclear Medicine Transcript Welcome to Radiology Info dot org ... I’d like to talk to you about nuclear medicine. Nuclear medicine offers the potential to identify ...

Explaining variation in nascent entrepreneurship

NARCIS (Netherlands)

A.J. van Stel (André); A.R.M. Wennekers (Sander); P. Reynolds (Paul); A.R. Thurik (Roy)

2004-01-01

textabstractThis paper aims at explaining cross-country variation in nascent entrepreneurship. Regression analysis is applied using various explanatory variables derived from three different approaches. We make use of the Global Entrepreneurship Monitor database, including nascent entrepreneurship

Explaining nascent entrepreneurship across countries

NARCIS (Netherlands)

A.R. Thurik (Roy); A.J. van Stel (André); A.R.M. Wennekers (Sander); P. Reynolds (Paul)

2003-01-01

textabstractThis paper aims at explaining cross-country variation in nascent entrepreneurship. Regression analysis is applied using various explanatory variables derived from three different approaches. We make use of the Global Entrepreneurship Monitor database, including nascent entrepreneurship

Měkkýši údolí Vltavy (Čechy)

Czech Academy of Sciences Publication Activity Database

Horáčková, J.; Ložek, V.; Beran, L.; Juřičková, L.; Podroužková, Š.; Peterka, Jiří; Čech, Martin

2014-01-01

Roč. 13, - (2014), s. 12-105 ISSN 1336-6939 Institutional support: RVO:60077344 Keywords : faunistics * inventory * Mollusca * river floodplain * Lucilla scintilla * Margaritifera margaritifera Subject RIV: EH - Ecology, Behaviour

Distribution of DTHS3 satellite DNA across 12 bivalve species Eva ...

Indian Academy of Sciences (India)

Windows User

In this work, characterization of DTHS3 satellite DNA was further expanded within the Class. Bivalvia. Monomer variants of DTHS3 satDNA were compared in 12 bivalve species belonging to two different Subclasses, Heterodonta and Pteriomorphia. This satDNA, whose age is estimated to a minimum of 516 Ma, ...

Browse Title Index

African Journals Online (AJOL)

Items 101 - 150 of 270 ... ... L. 1758 (Bivalvia: Arcidae) from a Sandy/Muddy Beach near Dar es Salaam, .... Settlement on Pearl Oyster Collectors in Kenya: Seasonality and Abundance, Abstract PDF ... Vol 15, No 1 (2016), Microalgal distribution, diversity and ... Vol 14, No 1&2 (2015), Micro-tidal dependent phytoplankton ...

Astronomy Explained

Science.gov (United States)

North, Gerald

Every year large numbers of people take up the study of astronomy, mostly at amateur level. There are plenty of elementary books on the market, full of colourful photographs, but lacking in proper explanations of how and why things are as they are. Many people eventually wish to go beyond the 'coffee-table book' stage and study this fascinating subject in greater depth. This book is written for them. In addition, many people sit for public examinations in this subject each year and this book is also intended to be of use to them. All the topics from the GCSE syllabus are covered here, with sample questions at the end of each chapter. Astronomy Explained provides a comprehensive treatment of the subject in more depth than is usually found in elementary works, and will be of interest to both amateur astronomers and students of astronomy.

’n Vergelyking van die Mollusca-diversiteit in die Mooirivier (Noordwes-Provinsie soos gevind met opnames wat gemaak is in 1963 en weer 50 jaar later

Directory of Open Access Journals (Sweden)

Cornelius T. Wolmarans

2015-02-01

Full Text Available Die hoogste getal gedokumenteerde uitsterwings van enige belangrike taksonomiese groepword aan die Mollusca toegedig. Faktore wat hoofsaaklik hiervoor verantwoordelik is, sluitonder meer omgewingsveranderinge en antropogeniese impakte in wat tot die tot niet gaanvan die habitat aanleiding gee. Daarbenewens is die bewaringstatus van minder as 2% van dieongeveer 7000 molluskspesies wêreldwyd bekend tot dusver nog nie behoorlik geassesseernie. Die doel van die huidige ondersoek wat in 2014 uitgevoer is, was om die molluskdiversiteitvan die Mooirivier met die resultate van 1963 te vergelyk. Dit is gedoen deur ’n opnameuit te voer van die molluskdiversiteit by dieselfde lokaliteite as in 1963. Twee opnames isgemaak tydens ’n vroeë- en laatlaagvloeiperiode in 2014 by agt lokaliteite wat met dié vandie 1963-opnames ooreenstem. Die pH, elektriese geleiding (EG en temperatuur is ook byelk van die lokaliteite gemeet. Die identiteit van die 14 slakspesies wat in 1963 gevind is, hetooreengestem met 14 van die 15 in 2014. Die uitheemse indringerspesie Physa acuta is tydensdie 2014-opname vir die eerste keer in hierdie rivier gevind, waarskynlik weens ’n toename inorganiese verryking. In die 1963-opname is Burnupia mooiensis en Pisidium langlyanum by diemeeste lokaliteite gevind, en in 2014 Gyraulus connollyi en Ferrissia cawstoni. Die meeste van diemolluske uit hierdie gebied wat voorheen op rekord gestel is, is in 2014 gevind. Die pH watin 2014 ’n geringe tot aansienlike verlaging getoon het, word aan mynversuring toegeskryfen het nie ’n merkbare invloed op die molluskdiversiteit gehad nie. Die hoër elektriesegeleiding wat tydens die 2014-opname gemeet is, het vanweë die verdraagsaamheid vanvarswatermolluske in hierdie verband, ook geen verandering in die molluskdiversiteit teweeggebring nie. Die temperatuur was in die laatlaagvloei deurgaans hoër. Ondanks die feit dathierdie studies vyf dekades uitmekaar gedoen is en antropogeniese impakte

Journalism and Explaining News Content

NARCIS (Netherlands)

Albæk, E.; Skovsgaard, M.; de Vreese, C.H.; Nussbaum, J.F.

Three models are presented to explain variation in news content. In the first model the explanation is based on the individual journalist, in the second model on the professional journalist, and in the third model on the organized journalist. The individual journalist model focuses on how the

Explaining Infinite Series--An Exploration of Students' Images

Science.gov (United States)

Champney, Danielle Dawn

2013-01-01

This study uses self-generated representations (SGR)--images produced in the act of explaining--as a means of uncovering what university calculus students understand about infinite series convergence. It makes use of student teaching episodes, in which students were asked to explain to a peer what that student might have missed had they been…

Can human error theory explain non-adherence?

Science.gov (United States)

Barber, Nick; Safdar, A; Franklin, Bryoney D

2005-08-01

To apply human error theory to explain non-adherence and examine how well it fits. Patients who were taking chronic medication were telephoned and asked whether they had been adhering to their medicine, and if not the reasons were explored and analysed according to a human error theory. Of 105 patients, 87 were contacted by telephone and they took part in the study. Forty-two recalled being non-adherent, 17 of them in the last 7 days; 11 of the 42 were intentionally non-adherent. The errors could be described by human error theory, and it explained unintentional non-adherence well, however, the application of 'rules' was difficult when considering mistakes. The consideration of error producing conditions and latent failures also revealed useful contributing factors. Human error theory offers a new and valuable way of understanding non-adherence, and could inform interventions. However, the theory needs further development to explain intentional non-adherence.

Teachers mathematical communication profile in explaining subject matter

Science.gov (United States)

Umami, Rohmatul; Budayasa, I. Ketut; Suwarsono, St.

2017-12-01

This study aimed to see a teachers mathematical communication profile in explaining a subject matter. It is a qualitative research. A high-school junior teacher (i.e., a teacher with 1- to 5-year experience) teaching mathematics at X-Social Class was selected as the subject of this study. The data was collected by observing the teachers mathematical communication in explaining a given material (i.e., the rule of sine) in class and an in-depth interview would be organized respectively. The result showed that the junior teacher explained the subject matter in systematic, complete, fluent, and centered manner. In this case, she began with reminding students on the previous material related to the current material to be learned, informing the current learning objectives, and finally delivering the subject matter. To support her explanation, the teacher also provided some related information, led the students attention into the given material by asking them particular related questions, and did not use any confusing terms. However, the study found that some of high-school teachers still used less appropriate language in explaining materials.

Can Marxism Explain America's Racism?

Science.gov (United States)

Willhelm, Sidney M.

1980-01-01

The Marxist interpretation of the Black experience in America has always had difficulty explaining various noneconomic aspects of racism. A perspective is needed that can blend racism as a variable in relationship with economic variables. To reach this perspective, the labor process within capitalism must be more fully understood. (Author/GC)

Does market competition explain fairness?

Science.gov (United States)

Descioli, Peter

2013-02-01

The target article by Baumard et al. uses their previous model of bargaining with outside options to explain fairness and other features of human sociality. This theory implies that fairness judgments are determined by supply and demand but humans often perceive prices (divisions of surplus) in competitive markets to be unfair.

A model for diagnosing and explaining multiple disorders.

Science.gov (United States)

Jamieson, P W

1991-08-01

The ability to diagnose multiple interacting disorders and explain them in a coherent causal framework has only partially been achieved in medical expert systems. This paper proposes a causal model for diagnosing and explaining multiple disorders whose key elements are: physician-directed hypotheses generation, object-oriented knowledge representation, and novel explanation heuristics. The heuristics modify and link the explanations to make the physician aware of diagnostic complexities. A computer program incorporating the model currently is in use for diagnosing peripheral nerve and muscle disorders. The program successfully diagnoses and explains interactions between diseases in terms of underlying pathophysiologic concepts. The model offers a new architecture for medical domains where reasoning from first principles is difficult but explanation of disease interactions is crucial for the system's operation.

Molluscan shell evolution with review of shell calcification hypothesis

Czech Academy of Sciences Publication Activity Database

Furuhashi, T.; Schwarzinger, C.; Mikšík, Ivan; Smrž, Miloslav; Beran, A.

2009-01-01

Roč. 154, č. 3 (2009), s. 351-371 ISSN 1096-4959 Institutional research plan: CEZ:AV0Z50110509 Keywords : mollusca * shell * biomineralization Subject RIV: CE - Biochemistry Impact factor: 1.607, year: 2009

Estudos higiênicos sôbre os crustáceos e moluscos da Baía de Guanabara (Rio de Janeiro

Directory of Open Access Journals (Sweden)

Lejeune Pacheco Henriques de Oliveira

1944-04-01

Full Text Available Revisão da literatura médica sôbre higiene de crustáceos e moluscos marinhos. Intoxicações por elementos extranhos às carnes de crustáceos e moluscos: por sais de cobre, vegetais tóxicos; estranho e chumbo nas conservas de crustáceos; botulismo. Putrefação de ostras e doenças de ostras provocadas por cogumelos; crustáceos e moluscos guardados em geladeiras bolorentas. Lista das espécies de moluscos comestíveis da Bahia de Guanabara. Lista das espécies de crustáceos comestíveis da Bahia de Guanabara. Veiculação de micro-organismos patogênicos ao homem por intermédio das carnes de crustáceos e de moluscos: veiculação do vibrião colérico, dos bacilos tíficos e paratíficos e de germes do grupo coli e do gênero Proteus. Vitalidade dos bacilos tíficos nas ostras. Listas dos moluscos veiculadores dos agentes causadores das febres tíficas e paratíficas. Conceitos antigos e modernos sõbre intoxicações por crustáceos; partidas de crustáceos salubres ou não conforme o local de venda. Estudos experimentais sôbre a "talassina" princípio tóxico existente em alguns crustáceos. "Mitilotoxina", intoxicações por mexilhões e outros acidentes incriminados aos moluscos. Enterotoxina estavfilocócica em ostras. Métodos de determinação da salubridade dos moluscos; verificações nas ostras brasileiras. Depuração dos crustáceos pelas soluções cloradas. Estabulação de caranguejos denominados vulgarmente de "guaiamus" e "ussás".Recording main medical publication on Hygiene of Mollusca and Crustacea. Food-poisoning. Decomposing oysters, and shell-fish sickness by fungi. Catalogue of eatable Crustacea and Mollusca of Rio de Janeiro. Significance of Mollusca and Crustacea in the spread of diseases. Longevity of Vibrio comma, Eberthella typhosa, Salmonella schottmuelleri, Salmonella paratiphi. Escherichia coli in oysters, Microorganisms in marked oysters. Comparison old written papers with moderns publications on food

Development and Assessment of Self-explaining Skills in College Chemistry Instruction

Science.gov (United States)

Villalta-Cerdas, Adrian

The prevalent trend in chemistry instruction relies on what has been described as the classroom game. In this model, students take a passive role and the instructor does all the explaining (thinking), and learning is trivialized to knowing the correct answers (memorizing) and being able to produce them when prompted (regurgitating). The generation of explanations is central to scientific and technological development. In the process of figuring out explanations, the generation of inferences relies on the application of skills associated with scientific behaviors (e.g., analytical reasoning and critical thinking). The process of explanation generation causes a deeper analysis and revision of the scientific models, thus impacting the conceptual understanding of such models. Although the process of generating authentic explanations is closer to the experience of doing science, this process is seldom replicated in science instruction. Self-explaining refers to the generation of inferences about causal connections between objects and events. In science, this may be summarized as making sense of how and why actual or hypothetical phenomena take place. Research findings in educational psychology show that implementing activities that elicit self-explaining improves learning in general and specifically enhances authentic learning in the sciences. Research also suggests that self-explaining influences many aspects of cognition, including acquisition of problem-solving skills and conceptual understanding. Although the evidence that links self-explaining and learning is substantial, most of the research has been conducted in experimental settings. The purpose of this work was to advance knowledge in this area by investigating the effect of different self-explaining tasks on self-explaining behavior and the effect of engaging in different levels of self-explaining on learning chemistry concepts. Unlike most of the research in the field, this work did not focus on advancing

Macrozoobenthos Community Structure In The Estuary of Donan River, Cilacap, Central Java Province, Indonesia

Directory of Open Access Journals (Sweden)

Taufik Fakih Hakiki

2017-12-01

Full Text Available Estuary of Donan Riverwhich is adjacent to Segara Anakan Lagoon in Cilacap, Central Java Province (Indonesia has been used for a number of activities such asfishieries, agriculture, industry, harbor, and tourism activities.  The aim of this study is to analyze the ecosystem condition based on mazcrozoobenthos community structure. This study was conducted from Augustus 2015 to January 2016. Samples were collected monthly at five stations from the river close area to the ocean close area. The study was conducted to identify kinds of generaand densityof themacrozoobenthos, and analyze substrates and water quality.Data analysis was performed onabundance, diversity, evenness and dominance indexes.Based on the study, macrozoobenthos at the estuary of Donan River consists of three classes i.e Gastropod (12 genera, Bivalvia(9 genera, and Polychaeta (6 genera. Based on the sampling location, Gastropod and Bivalvia are the largest composition found at five stations. Based on the sampling location, the macrozoobenthos density, diversity index, evennes index,and dominance index can be inferred that the estuary of Donan River is classified to be moderately ecological polluted.

Linear Algebra Thoroughly Explained

CERN Document Server

Vujičić, Milan

2008-01-01

Linear Algebra Thoroughly Explained provides a comprehensive introduction to the subject suitable for adoption as a self-contained text for courses at undergraduate and postgraduate level. The clear and comprehensive presentation of the basic theory is illustrated throughout with an abundance of worked examples. The book is written for teachers and students of linear algebra at all levels and across mathematics and the applied sciences, particularly physics and engineering. It will also be an invaluable addition to research libraries as a comprehensive resource book for the subject.

Explaining Interaction Effects within and across Levels of Analysis

DEFF Research Database (Denmark)

Andersson, Ulf; Cuervo-Cazurra, Alvaro; Nielsen, Bo Bernhard

2014-01-01

Many manuscripts submitted to the Journal of International Business Studies propose an interaction effect in their models in an effort to explain the complexity and contingency of relationships across borders. In this article, we provide guidance on how best to explain the interaction effects...

Bioaccumulation and elimination of 60 Co and 137 Cs by Anomalocardia brasiliana (Gmelin, 1791) (Mollusca bivalvia). Remobilization of 60 Co, retained in marine sediment by microbial activity

International Nuclear Information System (INIS)

Mayr, L.M.

1984-05-01

It was studied the capacity of a bi valve mollusc Anomalocardia brasiliana, which lives in the local bottom sediment, to remobilize 60 Co previously sorbed in the sediment. Laboratory experiments demonstrated that the transference of 60 Co from the sediment to the animal was insignificant (bioaccumulation factor (BF) of the order of 10 -3 ). At the same time, the capacity of microorganisms, present in the bottom sediment, to remobilize 60 Co was studied. The results showed that this via of transference was important, considering the much greater microorganism biomass in relation to the biomass of bentonic organisms, as a whole. For 137 Cs the determined BF from water to the animal was 2.2. and, as in the case of 60 Co, the soft tissues concentrated more 137 Cs than shell. Remaining viscera showed the highest BFs. In another series of experiments, the loss of 60 Co or 137 Cs, previously accumulated by A. brasiliana, was followed in aquaria with or without sediment and the respective biological half-lives were calculated. Soft tissues retained 60 Co longer (biological half-life = 117 days) than shells, whereas for 137 Cs the opposite was observed and shells showed a biological half life of 38.5 days. The low values of 60 Co and 137 Cs BF S do not allow to classify A. brasiliana as good biological indicator for pollution by there radionuclides. However since A brasiliana is consumed by the local population and is commercialized to other areas, it was recommended that its contamination by 60 Co or 137 Cs should be monitored. (author)

Evaluation of the levels of Br, Cl, K, Mg, Mn and V in Perna perna Mussels (Linnaeus, 1758: Mollusca, Bivalvia) collected in coast of Sao Paulo, Brazil

International Nuclear Information System (INIS)

Seo, Daniele; Vasconcellos, Marina B.A.; Saiki, Mitiki; Catharino, Marilia G.M.; Moreira, Edson G.; Sousa, Eduinetty C.P.M. de

2013-01-01

In this study the content of Br, Cl, K, Mg, Mn and V was evaluated in samples of Perna perna mussels collected in coastal regions of Sao Paulo (Ponta de Itaipu and Palmas Island, in Santos) subjected to anthropogenic contamination, to compare these values with those of mussels from reference site of Cocanha Beach (in Caraguatatuba). The mussels were collected seasonally from September 2008 to July 2009. They were cleaned, ground, homogenized, lyophilized and then analyzed by Instrumental Neutron Activation Analysis (INAA). The INAA procedure consisted in the irradiation of the samples and synthetic elemental standards for 8 and 10 s, under a thermal neutron flux of 6.6 x 10 12 n cm -2 s -1 in the IEA-R1 nuclear research reactor. For quality control of analytical results, certified reference materials NIST 1566b Oyster Tissue and NIST 2876 Mussel Tissue were analyzed and their results indicated good accuracy. The ranges of concentrations (dry basis) of the elements obtained in mussels collected for the four seasons of the year were: 173.80 to 358.99 mg kg -1 for Br; 45658 ± 1811 to 109166 ± 824 mg kg -1 for Cl; 7043 ± 856 to 12506 ± 675 mg kg -1 for K; 2774 ± 211 to 5691 ± 717 mg kg -1 for Mg; 7.01 ± 0.30 to 29.74 ± 3.32 mg kg -1 for Mn and 0.77 ± 0.02 to 3.43 ± 0.28 mg kg -1 for V. The seasonal and spatial variations of these element concentrations were in this study. (author)

Evaluation of the levels of Br, Cl, K, Mg, Mn and V in Perna perna Mussels (Linnaeus, 1758: Mollusca, Bivalvia) collected in coast of Sao Paulo, Brazil

Energy Technology Data Exchange (ETDEWEB)

Seo, Daniele; Vasconcellos, Marina B.A.; Saiki, Mitiki; Catharino, Marilia G.M.; Moreira, Edson G., E-mail: danyseo@uol.com.br, E-mail: mbvascon@ipen.br, E-mail: mitiko@ipen.br, E-mail: mgcatharino@uol.com.br, E-mail: emoreira@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Sousa, Eduinetty C.P.M. de, E-mail: edvinett@usp.br [Universidade de Sao Paulo (IO/USP), Sao Paulo, SP (Brazil). Instituto Oceanografico. Laboratorio de Ecotoxicologia Marinha e Microfitobentos

2013-07-01

In this study the content of Br, Cl, K, Mg, Mn and V was evaluated in samples of Perna perna mussels collected in coastal regions of Sao Paulo (Ponta de Itaipu and Palmas Island, in Santos) subjected to anthropogenic contamination, to compare these values with those of mussels from reference site of Cocanha Beach (in Caraguatatuba). The mussels were collected seasonally from September 2008 to July 2009. They were cleaned, ground, homogenized, lyophilized and then analyzed by Instrumental Neutron Activation Analysis (INAA). The INAA procedure consisted in the irradiation of the samples and synthetic elemental standards for 8 and 10 s, under a thermal neutron flux of 6.6 x 10{sup 12} n cm{sup -2} s{sup -1} in the IEA-R1 nuclear research reactor. For quality control of analytical results, certified reference materials NIST 1566b Oyster Tissue and NIST 2876 Mussel Tissue were analyzed and their results indicated good accuracy. The ranges of concentrations (dry basis) of the elements obtained in mussels collected for the four seasons of the year were: 173.80 to 358.99 mg kg{sup -1} for Br; 45658 ± 1811 to 109166 ± 824 mg kg{sup -1} for Cl; 7043 ± 856 to 12506 ± 675 mg kg{sup -1} for K; 2774 ± 211 to 5691 ± 717 mg kg{sup -1} for Mg; 7.01 ± 0.30 to 29.74 ± 3.32 mg kg{sup -1} for Mn and 0.77 ± 0.02 to 3.43 ± 0.28 mg kg{sup -1} for V. The seasonal and spatial variations of these element concentrations were in this study. (author)

Students Explaining Science—Assessment of Science Communication Competence

Science.gov (United States)

Kulgemeyer, Christoph; Schecker, Horst

2013-12-01

Science communication competence (SCC) is an important educational goal in the school science curricula of several countries. However, there is a lack of research about the structure and the assessment of SCC. This paper specifies the theoretical framework of SCC by a competence model. We developed a qualitative assessment method for SCC that is based on an expert-novice dialog: an older student (explainer, expert) explains a physics phenomenon to a younger peer (addressee, novice) in a controlled test setting. The explanations are video-recorded and analysed by qualitative content analysis. The method was applied in a study with 46 secondary school students as explainers. Our aims were (a) to evaluate whether our model covers the relevant features of SCC, (b) to validate the assessment method and (c) to find characteristics of addressee-adequate explanations. A performance index was calculated to quantify the explainers' levels of competence on an ordinal scale. We present qualitative and quantitative evidence that the index is adequate for assessment purposes. It correlates with results from a written SCC test and a perspective taking test (convergent validity). Addressee-adequate explanations can be characterized by use of graphical representations and deliberate switches between scientific and everyday language.

Shell Biofilm Nitrification and Gut Denitrification Contribute to Emission of Nitrous Oxide by the Invasive Freshwater Mussel Dreissena polymorpha (Zebra Mussel)

Science.gov (United States)

Svenningsen, Nanna B.; Heisterkamp, Ines M.; Sigby-Clausen, Maria; Larsen, Lone H.; Nielsen, Lars Peter; Stief, Peter

2012-01-01

Nitrification in shell biofilms and denitrification in the gut of the animal accounted for N2O emission by Dreissena polymorpha (Bivalvia), as shown by gas chromatography and gene expression analysis. The mussel's ammonium excretion was sufficient to sustain N2O production and thus potentially uncouples invertebrate N2O production from environmental N concentrations. PMID:22492461

Plankton composition in the coastal waters between Jaigarh and Rajapur along west coast of India

Digital Repository Service at National Institute of Oceanography (India)

Nair, S.R.S.; Achuthankutty, C.T.; Nair, V.R.; Devassy, V.P.

, Mollusca, Decapoda, Chaetognatha, Tunicata and fish eggs and larvae were the major groups in the zooplankton population. The highest secondary production values were obtained off Ratnagiri and the average production for the Konkan coastal waters was found...

Tuned Normalization Explains the Size of Attention Modulations

OpenAIRE

Ni, Amy M.; Ray, Supratim; Maunsell, John H.R.

2012-01-01

The effect of attention on firing rates varies considerably within a single cortical area. The firing rate of some neurons is greatly modulated by attention while others are hardly affected. The reason for this variability across neurons is unknown. We found that the variability in attention modulation across neurons in area MT of macaques can be well explained by variability in the strength of tuned normalization across neurons. The presence of tuned normalization also explains a striking as...

Explaining Support Vector Machines: A Color Based Nomogram.

Directory of Open Access Journals (Sweden)

Vanya Van Belle

Full Text Available Support vector machines (SVMs are very popular tools for classification, regression and other problems. Due to the large choice of kernels they can be applied with, a large variety of data can be analysed using these tools. Machine learning thanks its popularity to the good performance of the resulting models. However, interpreting the models is far from obvious, especially when non-linear kernels are used. Hence, the methods are used as black boxes. As a consequence, the use of SVMs is less supported in areas where interpretability is important and where people are held responsible for the decisions made by models.In this work, we investigate whether SVMs using linear, polynomial and RBF kernels can be explained such that interpretations for model-based decisions can be provided. We further indicate when SVMs can be explained and in which situations interpretation of SVMs is (hitherto not possible. Here, explainability is defined as the ability to produce the final decision based on a sum of contributions which depend on one single or at most two input variables.Our experiments on simulated and real-life data show that explainability of an SVM depends on the chosen parameter values (degree of polynomial kernel, width of RBF kernel and regularization constant. When several combinations of parameter values yield the same cross-validation performance, combinations with a lower polynomial degree or a larger kernel width have a higher chance of being explainable.This work summarizes SVM classifiers obtained with linear, polynomial and RBF kernels in a single plot. Linear and polynomial kernels up to the second degree are represented exactly. For other kernels an indication of the reliability of the approximation is presented. The complete methodology is available as an R package and two apps and a movie are provided to illustrate the possibilities offered by the method.

Measuring and explaining house price developments

NARCIS (Netherlands)

De Vries, P.

2010-01-01

This study discusses ways of measuring and explaining the development of house prices. The goal of the research underpinning this dissertation was to develop a methodological framework for studying these developments. This framework relates, first, to correcting for changes in the composition of

Molluscan shell colour.

Science.gov (United States)

Williams, Suzanne T

2017-05-01

The phylum Mollusca is highly speciose, and is the largest phylum in the marine realm. The great majority of molluscs are shelled, including nearly all bivalves, most gastropods and some cephalopods. The fabulous and diverse colours and patterns of molluscan shells are widely recognised and have been appreciated for hundreds of years by collectors and scientists alike. They serve taxonomists as characters that can be used to recognise and distinguish species, however their function for the animal is sometimes less clear and has been the focus of many ecological and evolutionary studies. Despite these studies, almost nothing is known about the evolution of colour in molluscan shells. This review summarises for the first time major findings of disparate studies relevant to the evolution of shell colour in Mollusca and discusses the importance of colour, including the effects of visual and non-visual selection, diet and abiotic factors. I also summarise the evidence for the heritability of shell colour in some taxa and recent efforts to understand the molecular mechanisms underpinning synthesis of shell colours. I describe some of the main shell pigments found in Mollusca (carotenoids, melanin and tetrapyrroles, including porphyrins and bile pigments), and their durability in the fossil record. Finally I suggest that pigments appear to be distributed in a phylogenetically relevant manner and that the synthesis of colour is likely to be energetically costly. © 2016 Cambridge Philosophical Society.

Benthos off Cochin, Southwest coast of India

Digital Repository Service at National Institute of Oceanography (India)

Harkantra, S.N.; Parulekar, A.H.

Macro-invertebrate benthic fauna off Cochin mainly composed of polychaeta (82.45%), crustacea (7.62%), mollusca (5.92%), sipuncula (2.25%), nemertinea (0.96%) and echinodermata (0.80%). The maximum population density and biomass values were 304 plus...

Early development of the aplacophoran mollusc Chaetoderma

DEFF Research Database (Denmark)

Nielsen, Claus; Haszprunar, Gerhard; Ruthensteiner, Bernhard

2007-01-01

The early development of the trochophore larva of the aplacophoran Chaetoderma nitidulum (Mollusca: Caudofoveata = Chaetodermomorpha) is described using scanning and transmission electron microscopy and using fluorescence staining and confocal laser scanning microscopy of the muscle system...

Efecto de bacterias probióticas en el cultivo larvario del ostión de placer Crassostrea corteziensis (Bivalvia: Ostreidae

Directory of Open Access Journals (Sweden)

Angel Isidro Campa-Córdova

2011-03-01

Full Text Available El ostión de placer u ostra del Cortés (Crassostrea corteziensis se considera como una especie con potencial para ser cultivada en gran escala. Sin embargo, al igual que en otros bivalvos, la alta mortalidad que se presenta durante la etapa larvaria y juvenil, es el principal problema que limita el desarrollo del cultivo en el laboratorio. Un método que está ganando aceptación en la acuicultura es el uso de bacterias probióticas para controlar patógenos microbianos. Este estudio analiza el efecto de estas bacterias en la supervivencia y talla final de larvas de ostión de placer Crassostrea corteziensis. Se utilizó una cepa de bacterias ácido lácticas (cepa NS61 aisladas N. subnodosus, así como de bacilos aislados de L. vannamei (Pseudomonas aeruginosa, cepa YC58 y de C. corteziensis (Burkholderia cepacia, cepa Y021. Las cepas se evaluaron por inmersión en cultivos larvarios de C. corteziensis a dos concentraciones diferentes, hasta completar el estadio pediveliger. Los organismos se trataron con bacterias ácido lácticas (Lb, una mezcla de bacilos (Lb en proporción 1:1 y un grupo control. La concentración de 1x10(4UFC/ml registró una mayor supervivencia con Lb y Mb respecto al grupo control. La supervivencia con Mb a una concentración de 1x10(5UFC/ml fue mayor que la del grupo control y del grupo tratado con Lb. Los resultados mostraron que las larvas de C. corteziensis tratadas con probióticos no incrementaron significativamente su talla respecto a las larvas del grupo control. Mientras que las tratadas con Lb a la concentración mayor, 1x10(5UFC/ml, mostraron una disminución de la supervivencia respecto a las tratadas con 1x10(4UFC/ml. Este estudio demostró el efecto benéfico de cepas probióticas utilizadas individualmente o en mezcla en el cultivo larvario de C. corteziensis.Effect of probiotic bacteria on survival and growth of Cortez oyster larvae, Crassostrea corteziensis (Bivalvia: Ostreidae. Disease control

Explaining social class differences in depression and well-being.

Science.gov (United States)

Stansfeld, S A; Head, J; Marmot, M G

1998-01-01

Work characteristics, including skill discretion and decision authority, explain most of the socioeconomic status gradient in well-being and depression in middle-aged British civil servants from the Whitehall II Study, London. Social support explained about one-third of the gradient, life events and material difficulties less than one-third. Socioeconomic status was measured by employment grade. Work characteristics were based on the Karasek model, social support was measured by the Close Persons Questionnaire, depression by the General Health Questionnaire and well-being by the Affect Balance Scale. Despite a small contribution from social selective factors measured by upward mobility, the psychosocial work environment explained most of the cross-sectional socioeconomic status gradient in well-being and depression.

Do changes in connectivity explain desertification?

Science.gov (United States)

Desertification, broad-scale land degradation in drylands, is a major environmental hazard facing inhabitants of the world’s deserts as well as an important component of global change. There is no unifying framework that simply and effectively explains different forms of desertification. Here we arg...

Explaining Disparities in Unemployment Dynamics

OpenAIRE

Karanassou, Marika; Snower, Dennis J.

1993-01-01

This paper attempts to explain disparities among the unemployment experiences of different OECD countries in terms of the `fragility' of the short-run unemployment equilibrium (the impact of labour market shocks on the short-run unemployment rate) and the lag structure of the employment determination, wage setting, and labour force participation decisions. The effects of this lag structure on unemployment dynamics are captured through two general measures of `unemployment persistence' (occurr...

Explaining convergence of oecd welfare states

DEFF Research Database (Denmark)

Schmitt, C.; Starke, Peter

2011-01-01

of conditional convergence helps to both better describe and explain the phenomenon. By applying error correction models, we examine conditional convergence of various types of social expenditure in 21 OECD countries between 1980 and 2005. Our empirical findings go beyond the existing literature in two respects...

Explaining money creation by commercial banks

DEFF Research Database (Denmark)

Ravn, Ib

2015-01-01

Educators and economists concerned with monetary reform face the extraordinary challenge of explaining to the public and its elected representatives not only what a reformed system would look like, but also how the current system works. Centrally, the point that in a modern economy money is largely...... created by commercial banks, as explained by the Bank of England recently (McLeay, Radia & Thomas, 2014b), is often met with incredulity: “What do you mean, created?” This paper introduces five easy-to-grasp analogies that educators and reformers may use to convey key money-creation concepts to a lay...... audience. The analogies offered include (1) money as patches in an expandable patchwork quilt that covers a nation’s real assets, (2) the money supply as water in a bathtub with a faucet and a drain, (3) money understood as debt in a model economy run by schoolchildren, (4) the misleading concept of a bank...

Intragenomic sequence variation at the ITS1 - ITS2 region and at the 18S and 28S nuclear ribosomal DNA genes of the New Zealand mud snail, Potamopyrgus antipodarum (Hydrobiidae: mollusca)

Science.gov (United States)

Hoy, Marshal S.; Rodriguez, Rusty J.

2013-01-01

Molecular genetic analysis was conducted on two populations of the invasive non-native New Zealand mud snail (Potamopyrgus antipodarum), one from a freshwater ecosystem in Devil's Lake (Oregon, USA) and the other from an ecosystem of higher salinity in the Columbia River estuary (Hammond Harbor, Oregon, USA). To elucidate potential genetic differences between the two populations, three segments of nuclear ribosomal DNA (rDNA), the ITS1-ITS2 regions and the 18S and 28S rDNA genes were cloned and sequenced. Variant sequences within each individual were found in all three rDNA segments. Folding models were utilized for secondary structure analysis and results indicated that there were many sequences which contained structure-altering polymorphisms, which suggests they could be nonfunctional pseudogenes. In addition, analysis of molecular variance (AMOVA) was used for hierarchical analysis of genetic variance to estimate variation within and among populations and within individuals. AMOVA revealed significant variation in the ITS region between the populations and among clones within individuals, while in the 5.8S rDNA significant variation was revealed among individuals within the two populations. High levels of intragenomic variation were found in the ITS regions, which are known to be highly variable in many organisms. More interestingly, intragenomic variation was also found in the 18S and 28S rDNA, which has rarely been observed in animals and is so far unreported in Mollusca. We postulate that in these P. antipodarum populations the effects of concerted evolution are diminished due to the fact that not all of the rDNA genes in their polyploid genome should be essential for sustaining cellular function. This could lead to a lessening of selection pressures, allowing mutations to accumulate in some copies, changing them into variant sequences.                   

Bioaccumulation and elimination of {sup 60} Co and {sup 137} Cs by Anomalocardia brasiliana (Gmelin, 1791) (Mollusca bivalvia). Remobilization of {sup 60} Co, retained in marine sediment by microbial activity; Bioacumulacao e eliminacao de {sup 60}Co e {sup 137}Cs por anomalocardia brasiliana (Gmelin, 1791) (Mollusca bivalvia). Remobilizacao de {sup 60}Co retido em sedimento marinho por atividade microbiana

Energy Technology Data Exchange (ETDEWEB)

Mayr, L M

1984-05-01

It was studied the capacity of a bi valve mollusc Anomalocardia brasiliana, which lives in the local bottom sediment, to remobilize {sup 60} Co previously sorbed in the sediment. Laboratory experiments demonstrated that the transference of {sup 60} Co from the sediment to the animal was insignificant (bioaccumulation factor (BF) of the order of 10{sup -3}). At the same time, the capacity of microorganisms, present in the bottom sediment, to remobilize {sup 60} Co was studied. The results showed that this via of transference was important, considering the much greater microorganism biomass in relation to the biomass of bentonic organisms, as a whole. For {sup 137} Cs the determined BF from water to the animal was 2.2. and, as in the case of {sup 60} Co, the soft tissues concentrated more {sup 137} Cs than shell. Remaining viscera showed the highest BFs. In another series of experiments, the loss of {sup 60} Co or {sup 137} Cs, previously accumulated by A. brasiliana, was followed in aquaria with or without sediment and the respective biological half-lives were calculated. Soft tissues retained {sup 60} Co longer (biological half-life = 117 days) than shells, whereas for {sup 137} Cs the opposite was observed and shells showed a biological half life of 38.5 days. The low values of {sup 60} Co and {sup 137} Cs BF{sub S} do not allow to classify A. brasiliana as good biological indicator for pollution by there radionuclides. However since A brasiliana is consumed by the local population and is commercialized to other areas, it was recommended that its contamination by {sup 60} Co or {sup 137} Cs should be monitored. (author).

Phenotypic variance explained by local ancestry in admixed African Americans.

Science.gov (United States)

Shriner, Daniel; Bentley, Amy R; Doumatey, Ayo P; Chen, Guanjie; Zhou, Jie; Adeyemo, Adebowale; Rotimi, Charles N

2015-01-01

We surveyed 26 quantitative traits and disease outcomes to understand the proportion of phenotypic variance explained by local ancestry in admixed African Americans. After inferring local ancestry as the number of African-ancestry chromosomes at hundreds of thousands of genotyped loci across all autosomes, we used a linear mixed effects model to estimate the variance explained by local ancestry in two large independent samples of unrelated African Americans. We found that local ancestry at major and polygenic effect genes can explain up to 20 and 8% of phenotypic variance, respectively. These findings provide evidence that most but not all additive genetic variance is explained by genetic markers undifferentiated by ancestry. These results also inform the proportion of health disparities due to genetic risk factors and the magnitude of error in association studies not controlling for local ancestry.

Rostrokonchy z devonských sedimentů moravskoslezské pánve

Czech Academy of Sciences Publication Activity Database

Weinerová, Hedvika; Weiner, Tomáš; Hladil, Jindřich

2017-01-01

Roč. 50, č. 1 (2017), s. 153-157 ISSN 0514-8057 R&D Projects: GA ČR GA14-18183S Institutional support: RVO:67985831 Keywords : Rostroconchia * Mollusca * Devonian * Moravo-Silesian Basin Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Paleontology

Identification of Genes Related to Learning and Memory in the Brain Transcriptome of the Mollusc, "Hermissenda Crassicornis"

Science.gov (United States)

Tamvacakis, Arianna N.; Senatore, Adriano; Katz, Paul S.

2015-01-01

The sea slug "Hermissenda crassicornis" (Mollusca, Gastropoda, Nudibranchia) has been studied extensively in associative learning paradigms. However, lack of genetic information previously hindered molecular-level investigations. Here, the "Hermissenda" brain transcriptome was sequenced and assembled de novo, producing 165,743…

Micrallecto uncinata n. gen., n.sp., a parasitic copepod from a remarkable host, the pteropod Pneumoderma

NARCIS (Netherlands)

Stock, Jan H.

1971-01-01

A new genus and species of copepod crustacean parasite, Micrallecto uncinata, is described from Pneumoderma pygmaeum (Tesch, 1903), a gymnosome pteropod (Mollusca) collected West of Bermuda. The parasite probably belongs to the family Splanchnotrophidae and is the first copepod associate reported

A model to explain human voice production

Science.gov (United States)

Vilas Bôas, C. S. N.; Gobara, S. T.

2018-05-01

This article presents a device constructed with low-cost material to demonstrate and explain voice production. It also provides a contextualized, interdisciplinary approach to introduce the study of sound waves.

Explaining Teachers' Use of Textbooks

Science.gov (United States)

Reichenberg, Monica

2016-01-01

In educational systems without comprehensive systems for regulating textbooks, teachers can exert considerable influence on the use of textbooks. However, existing research has not yet identified the mechanisms of this use. Accordingly, the aim of this article is to examine and explain teachers' strategic use of textbooks. I administered a…

AN EVALUATION OF THREE CONVENTIONAL HISTOLOGICAL TECHNIQUES FOR STAINING THE CERATA OF CRATENA PILATA

Science.gov (United States)

Fixation and staining methods for different types of tissue in the marine nudibranch Cratena pilata were evaluated. Cratena pilata, a marine snail in the Phylum Mollusca, has the ability to take stinging cells, called nematocysts, from ingested animals belonging to another phylum...

Machine learning and deep analytics for biocomputing: call for better explainability.

Science.gov (United States)

Petkovic, Dragutin; Kobzik, Lester; Re, Christopher

2018-01-01

The goals of this workshop are to discuss challenges in explainability of current Machine Leaning and Deep Analytics (MLDA) used in biocomputing and to start the discussion on ways to improve it. We define explainability in MLDA as easy to use information explaining why and how the MLDA approach made its decisions. We believe that much greater effort is needed to address the issue of MLDA explainability because of: 1) the ever increasing use and dependence on MLDA in biocomputing including the need for increased adoption by non-MLD experts; 2) the diversity, complexity and scale of biocomputing data and MLDA algorithms; 3) the emerging importance of MLDA-based decisions in patient care, in daily research, as well as in the development of new costly medical procedures and drugs. This workshop aims to: a) analyze and challenge the current level of explainability of MLDA methods and practices in biocomputing; b) explore benefits of improvements in this area; and c) provide useful and practical guidance to the biocomputing community on how to address these challenges and how to develop improvements. The workshop format is designed to encourage a lively discussion with panelists to first motivate and understand the problem and then to define next steps and solutions needed to improve MLDA explainability.

The Mass-Dimension Relationships in the Mussels Mytilus Galloprovincialis (Mollusca, Bivalvia from Different Phenotypical Groups in Periphyton Populations near Odessa Coast, the North-Western Part of Black Sea

Directory of Open Access Journals (Sweden)

Govorin I. A.

2016-06-01

Full Text Available The data of the size-mass indices in the mussels Mytilus galloprovincialis (Lamarck, 1819 from three phenotypic groups - brown, dark violet (black and “zebra” (brown with radial black stripes shells in the periphyton settlements on the concrete traverses near Odessa coast, the North-western part of Black Sea (Ukraine, in March-November 2014-2015 are presented. A comparative evaluation has been made on the relationships of total mass of the mollusks, wet and dry mass of their soft body and mass of the shells on the one hand, and the size of animals (length of its shells on the other hand, in the each of phenotypical groups from the five marine beach areas. It is shown, that in the marine areas with different degrees of isolation from the open sea by coast-protection engineering constructions, the mussels from different phenotypes have almost the same size-mass characteristics. Only the dry weight of soft animal body, which indicated to fatness of mollusk and therefore demonstrated his biological prosperity in specific hydrological conditions, can serve as a reliable criterion which can mark the shellfish habitats with different gradients of environmental factors.

Phylogenetic study of the oxytocin-like immunoreactive system in invertebrates.

Science.gov (United States)

Mizuno, J; Takeda, N

1988-01-01

1. A phylogenetic study of oxytocin (OXT)-like immunoreactive cells was performed by the PAP method in the central nervous system of invertebrates. 2. The immunoreactivity was detected in the nerve cells of Hydra magnipapillata of the Coelenterata; Neanthes japonica and Pheretima communissima of the Annelida; Oncidium verrucosum, Limax marginatus and Meretrix lamarckii of the Mollusca; and Baratha brassica of the Arthropoda. 3. No immunoreactive cells were found in Bipalium sp. of the Platyhelminthes; Pomacea canaliculata, Aplysia kurodai, Bradybaena similaris and Achatina fulica of the Mollusca; and Gnorimosphaeroma rayi, Procambarus clarkii, Hemigrapsus sanguineus, Helice tridens and Gryllus bimaculatus of the Arthropoda; Asterina pectinifera of the Echinodermata; and Halocynthia roretzi of the Protochordata. 4. These results demonstrate that an OXT-immunoreactive substance is widely present not only in vertebrates but also in invertebrates. 5. OXT seems to have been introduced into these invertebrates at an early stage of their phylogenetic history.

Explaining focal points: Cognitive hierarchy theory versus team reasoning

OpenAIRE

Bardsley, Nicholas; Mehta, Judith; Starmer, Chris; Sugden, Robert

2008-01-01

This paper reports experimental tests of two alternative explanations of how players use focal points to select equilibria in one-shot coordination games. Cognitive hierarchy theory explains coordination as the result of common beliefs about players’ pre-reflective inclinations towards the relevant strategies; the theory of team reasoning explains it as the result of the players’ using a non-standard form of reasoning. We report two experiments. One finds strong support for team reasoning; th...

Students' Development and Use of Models to Explain Electrostatic Interactions

Science.gov (United States)

Mayer, Kristin Elizabeth

The National Research Council (2012) recently published A Framework for K-12 Science Education that describes a vision for science classrooms where students engage in three dimensions--scientific and engineering practices, crosscutting concepts, and disciplinary core ideas--to explain phenomena or observations they can make about the universe around them. This vision of science instruction is a significant shift from current classroom instruction. This dissertation provides detailed examples of how students developed and used models to build causal explanations of phenomena. I co-taught classes that focused on having students develop and revise models of electric fields and atomic structure using a curriculum that was designed to align with the three-dimensional vision of learning. I developed case studies of eleven students from these classes. I analyzed the students' responses and interviewed the students throughout the school year. By comparing and contrasting the analysis across the analysis of students' interviews, I identified four themes: 1) students could apply their ideas to explain novel and abstract phenomena; 2) students struggled to connect changes in their atomic models to evidence, but ended up with dynamic models of atomic structure that they could apply to explain phenomena; 3) students developed models of atomic structure that they applied to explain phenomena, but they did not use models of electric fields in this way; and 4) too much focus on details interfered with students' ability to apply their models to explain new phenomena. This dissertation highlights the importance of focusing on phenomena in classrooms that aim at aligning with three-dimensional learning. Students struggled to focus on specific content and apply their ideas to explain phenomena at the same time. In order to apply ideas to new context, students had to shift their focus from recalling ideas to applying the ideas they do have. A focus on phenomena allowed students to show

Critical Factors Explaining the Leadership Performance of High-Performing Principals

Science.gov (United States)

Hutton, Disraeli M.

2018-01-01

The study explored critical factors that explain leadership performance of high-performing principals and examined the relationship between these factors based on the ratings of school constituents in the public school system. The principal component analysis with the use of Varimax Rotation revealed that four components explain 51.1% of the…

Your Radiologist Explains Magnetic Resonance Angiography (MRA)

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Full Text Available ... Disorders Video: The Basketball Game: An MRI Story Radiology and You Sponsored by Image/Video Gallery Your ... Explains Magnetic Resonance Angiography (MRA) Transcript Welcome to Radiology Info dot org Hello, I’m Dr. Elliot ...

Your Radiologist Explains Magnetic Resonance Angiography (MRA)

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Full Text Available ... An MRI Story Radiology and You Sponsored by Image/Video Gallery Your Radiologist Explains Magnetic Resonance Angiography ( ... posted: How to Obtain and Share Your Medical Images Movement Disorders Video: The Basketball Game: An MRI ...

Using Expectancy Theory to Explain Performance Appraisal ...

African Journals Online (AJOL)

pc

2018-03-05

Mar 5, 2018 ... appraisal conducting style, the relation between the performance appraisal system and task ... the article first explains the theory model which is based expectancy theory. II. ... which in return lead to rewards. According to [12],.

Explorers Presentation: Explaining the Tides to Children

OpenAIRE

Institute, Marine

2015-01-01

Explaining the tides to children Presentation includes information about: Orbits of the Earth, Moon and Sun; Moon phases and the lunar cycle; Gravity; Gravity and the tide; Types of tides; The tides and me!; Tide tables; Extra insight

Explaining the Allocation of Regional Structural Funds

DEFF Research Database (Denmark)

Charron, Nicholas

2016-01-01

What regional factors can explain the heterogeneity in Structural Funds distribution to European Union regions? Past studies have shown that aside from the level of economic development and rates of unemployment, other political, and economic factors systematically explain why certain European...... Union regions receive greater funding than others, in particular where there is room for bargaining. In this article, a novel theory is posited which argues that the determination of Structural Funds is based on an interaction between a region’s formal institutions (the level of a regional autonomy......) and informal institutions (its level of quality of government). In cases of low regional autonomy, member states and European Union level actors prefer to allocate greater levels of Funds to regions with lower quality of government in order to increase cohesion. Yet in cases of high regional autonomy, risks...

The role of social factors in explaining crime

Directory of Open Access Journals (Sweden)

Siti Nur Zahara HAMZAH

2013-06-01

Full Text Available Utilizing Malaysia data from 1973 to 2008, the study reveals that crime can be influenced by population, fertility, unemployment, and GDP in either the long-run or short-run period. This study also further analysed beyond sample estimations of the variables involved and found that although violent crime can be explained in the short-run only from the VECM analysis, it is found to be explained by other explanatory variables in the long-run of beyond sample for at least 50 years ahead. It is important for policy makers to focus in both social structure and economic conditions to help prevent crime in the long-run.

Topology Explains Why Automobile Sunshades Fold Oddly

Science.gov (United States)

Feist, Curtis; Naimi, Ramin

2009-01-01

Automobile sunshades always fold into an "odd" number of loops. The explanation why involves elementary topology (braid theory and linking number, both explained in detail here with definitions and examples), and an elementary fact from algebra about symmetric group.

Does Asset Allocation Policy Explain 40, 90, 100 Percent of Performance?

OpenAIRE

Roger G. Ibbotson; Paul D. Kaplan

2001-01-01

Does asset allocation policy explain 40 percent, 90 percent, or 100 percent of performance? According to some well-known studies, more than 90 percent of the variability of a typical plan sponsor's performance over time is attributable to asset allocation. However, few people want to explain variability over time. Instead, an analyst might want to know how important it is in explaining the differences in return from one fund to another, or what percentage of the level of a typical fund's retu...

Food selection preference of different ages and sizes of black tiger ...

African Journals Online (AJOL)

Yomi

2012-03-15

Mar 15, 2012 ... Key words: Aquaculture, natural food, Penaeus monodon, Malaysia. INTRODUCTION ... Many researchers who reported on the diet of Penaeus species in ..... matter, annelida, mollusca and small fish in estuarine water. .... planktonic and benthic communities to fertilizer and feed application in shrimp ...

Stratigrafie a malakofauna holocenní výplně jeskyně Pod valem (Zádielská tiesňava, NP Slovenský kras)

Czech Academy of Sciences Publication Activity Database

Ložek, Vojen

2011-01-01

Roč. 2010, - (2011), s. 62-65 ISSN 0514-8057 Institutional research plan: CEZ:AV0Z30130516 Keywords : Slovak Karst * cave fill * extreme habitat * Holocene * Mollusca * Zebrina detrita Subject RIV: DB - Geology ; Mineralogy http://www.geology.cz/zpravy/obsah/2010/zpravy-2010-14.pdf

Chronostratigrafická revize a paleoklimatický význam osypu pod stěnou Martinky (CHKO) v Biosférické rezervaci Pálava

Czech Academy of Sciences Publication Activity Database

Ložek, Vojen

2011-01-01

Roč. 2010, - (2011), s. 66-69 ISSN 0514-8057 Institutional research plan: CEZ:AV0Z30130516 Keywords : Pálava Mils * talus deposit * Mollusca * Climatic Optimum * erosion Subject RIV: DB - Geology ; Mineralogy http://www.geology.cz/zpravy/obsah/2010/zpravy-2010-15.pdf

Water SA - Vol 43, No 2 (2017)

African Journals Online (AJOL)

Sensitivity to selected contaminants in a biological early warning system using Anodonta woodiana (Mollusca) · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. Luisa Giari, Fabio Vincenzi, Elisa Anna Fano, Ivano Graldi, Fernando Gelli, Giuseppe Castaldelli, 200-208.

Applicability of the black slug Arion ater for monitoring exposure to polycyclic aromatic hydrocarbons and their subsequent bioactivation into DNA binding metabolites

NARCIS (Netherlands)

Hamers, T.; Kalis, E.J.J.; Berg, van den J.H.J.; Maas, L.M.; Schooten, van F.J.; Murk, A.J.

2004-01-01

The applicability of terrestrial black slugs Arion ater (Mollusca, Gastropoda) was studied for biomonitoring environmental exposure to polycyclic aromatic hydrocarbons (PAHs). In laboratory experiments, slugs were orally exposed to benzo[a]pyrene (BaP) for a short term (3 days) or a long term (119

Your Radiologist Explains Magnetic Resonance Angiography (MRA)

Medline Plus

Full Text Available ... Sponsored by Image/Video Gallery Your Radiologist Explains Magnetic Resonance Angiography (MRA) Transcript Welcome to Radiology Info dot ... I’d like to talk with you about magnetic resonance angiography, or as it’s commonly known, MRA. MRA ...

Explaining the Evolution of Poverty

DEFF Research Database (Denmark)

Arndt, Channing; Hussain, Azhar; Jones, Edward Samuel

2012-01-01

We provide a comprehensive approach for analyzing the evolution of poverty using Mozambique as a case study. Bringing together data from disparate sources, we develop a novel “back-casting” framework that links a dynamic computable general equilibrium model to a micro-simulation poverty module....... This framework provides a new approach to explaining and decomposing the evolution of poverty, as well as to examining rigorously the coherence between poverty, economic growth, and inequality outcomes. Finally, various simple but useful and rarely-applied approaches to considering regional changes in poverty...

Explaining subsidiaries' knowledge-diffusion behaviours within MNEs

NARCIS (Netherlands)

Ho, H.C.

2007-01-01

This study explores how subsidiaries can contribute their advantages for the whole MNE in knowledge diffusion processes. The research model includes both organisational factors and local resources in a host country to explain subsidiaries' diffusion behaviours. We carried out an online survey for

How brain and neuronal networks explain human reality

Directory of Open Access Journals (Sweden)

Javier Monserrat

2017-02-01

Full Text Available How is human reality presented to us in phenomenological experience? It is the one we see daily in our personal and social life. We are made of matter, we are part of the evolutionary universe. In addition, a psychic life is formed in us: sensation, a system of perceptions, an integrated consciousness, a condition of psychological subject; We produce knowledge, emotions, motivations; But, above all, we have a mind that rationally moves and installs us into a world of human emotions; This emotional reason lies at the base of the search for the truth of the universe, the meaning of life and the moral responsibility, in personal and social life. Our human reality is, therefore, a personal reality. We are persons. Now, how does science, neurology, explain today the fact that our human reality possesses these properties that give us the personal condition? This should be able to be explained (this is the initial assumption from the physical-biological world. Now, in particular, how does science make it possible to explain that evolution has produced us in our condition of ratio-emotional persons? That is, what is the physical support that makes intelligible the psycho-bio-physical ontology that evolutionarily produces our personal phenomenological experience? This is, ultimately, still the fundamental question of human sciences. What science, namely neurology, must explain (that is, know the causes that have produced it is obvious: the fact of our sensibility-consciousness, our condition of psychic subjects, knowledge and emotional reason that have emerged in the universe; In such a way that, once the emotional reason emerges, it leads by itself to constitute the rational activity and the emotions of the human person aimed at building the meaning of his life. These are the issues we address in this article.

Vertigo substriata Jeffreys, faunae neerlandicae nova species, een zoogenaamd glaciaalrelikt

NARCIS (Netherlands)

Sunier, A.L.J.

1926-01-01

I. HET NEDERLANDSCHE MATERIAAL VAN VERTIGO SUBSTRIATA JEFFR.. Onder het vaak interessante materiaal van Nederlandsche Mollusca, dat den laatsten tijd door de Heeren W. F. van Hell en J. A. Nijkamp, studenten in de biologie te Leiden, aan 's Rijks Museum van Natuurlijke Historie werd afgestaan, trof

The oyster genome reveals stress adaptation and complexity of shell formation

DEFF Research Database (Denmark)

Zhang, Guofan; Fang, Xiaodong; Guo, Ximing

2012-01-01

The Pacific oyster Crassostrea gigas belongs to one of the most species-rich but genomically poorly explored phyla, the Mollusca. Here we report the sequencing and assembly of the oyster genome using short reads and a fosmid-pooling strategy, along with transcriptomes of development and stress re...

Malakostratigrafie vchodového valu Medvědí jeskyně ve Slovenském ráji

Czech Academy of Sciences Publication Activity Database

Ložek, Vojen

2012-01-01

Roč. 2011, podzim (2012), s. 219-222 ISSN 0514-8057 Institutional research plan: CEZ:AV0Z30130516 Keywords : Slovenský raj * Medvedia Cave * entrance rampart * Holocene * Mollusca * foam sinter Subject RIV: DB - Geology ; Mineralogy http://www.geology.cz/zpravy/obsah/2011/zpravy_2011-49.pdf

Bivalve wood borings of the ichnogenus Teredolites Leymerie from the Bohemian Cretaceous Basin (Upper Cretaceous, Czech Republic)

Czech Academy of Sciences Publication Activity Database

Kříž, J.; Mikuláš, Radek

2006-01-01

Roč. 13, č. 3 (2006), s. 159-174 ISSN 1042-0940 Institutional research plan: CEZ:AV0Z30130516 Keywords : Borings * Mollusca * sedimentary environment Subject RIV: EG - Zoology http://rzblx1.uni-regensburg.de/ezeit/detail.phtml?bibid=CASCR& colors =7&lang=en&jour_id=41560

Quantifying explainable discrimination and removing illegal discrimination in automated decision making

KAUST Repository

Kamiran, Faisal; Žliobaite, Indre; Calders, Toon

2012-01-01

discrimination and do not take into account that part of the discrimination may be explainable by other attributes. For example, in a job application, the education level of a job candidate could be such an explainable attribute. If the data contain many highly

Children's Theories and the Drive to Explain

Science.gov (United States)

Schwitzgebel, Eric

Debate has been growing in developmental psychology over how much the cognitive development of children is like theory change in science. Useful debate on this topic requires a clear understanding of what it would be for a child to have a theory. I argue that existing accounts of theories within philosophy of science and developmental psychology either are less precise than is ideal for the task or cannot capture everyday theorizing of the sort that children, if they theorize, must do. I then propose an account of theories that ties theories and explanation very closely together, treating theories primarily as products of a drive to explain. I clarify some of the positions people have taken regarding the theory theory of development, and I conclude by proposing that psychologists interested in the ''theory theory'' look for patterns of affect and arousal in development that would accompany the existence of a drive to explain.

HIV As Trojan Exosome: Immunological Paradox Explained?

Science.gov (United States)

Hildreth, James E K

2017-01-01

The HIV pandemic is still a major global challenge, despite the widespread availability of antiretroviral drugs. An effective vaccine would be the ideal approach to bringing the pandemic to an end. However, developing an effective HIV vaccine has proven to be an elusive goal. Three major human HIV vaccine trials revealed a strong trend toward greater risk of infection among vaccine recipients versus controls. A similar observation was made in a macaque SIV vaccine study. The mechanism explaining this phenomenon is not known. Here, a model is presented that may explain the troubling results of vaccine studies and an immunological paradox of HIV pathogenesis: preferential infection of HIV-specific T cells. The central hypothesis of this perspective is that as "Trojan exosomes" HIV particles can directly activate HIV-specific T cells enhancing their susceptibility to infection. Understanding the biology of HIV as an exosome may provide insights that enable novel approaches to vaccine development.

Explaining the VET Applied Research Developmental Framework

Science.gov (United States)

Simon, Linda; Beddie, Francesca M.

2017-01-01

This document explains the VET Applied Research Developmental Framework, created as part of a project that explored how the vocational education and training (VET) sector could broaden its engagement in Australia's research and development (R&D) and innovation systems. Achieving this engagement will rely significantly on building the…

Quantifying explainable discrimination and removing illegal discrimination in automated decision making

KAUST Repository

Kamiran, Faisal

2012-11-18

Recently, the following discrimination-aware classification problem was introduced. Historical data used for supervised learning may contain discrimination, for instance, with respect to gender. The question addressed by discrimination-aware techniques is, given sensitive attribute, how to train discrimination-free classifiers on such historical data that are discriminative, with respect to the given sensitive attribute. Existing techniques that deal with this problem aim at removing all discrimination and do not take into account that part of the discrimination may be explainable by other attributes. For example, in a job application, the education level of a job candidate could be such an explainable attribute. If the data contain many highly educated male candidates and only few highly educated women, a difference in acceptance rates between woman and man does not necessarily reflect gender discrimination, as it could be explained by the different levels of education. Even though selecting on education level would result in more males being accepted, a difference with respect to such a criterion would not be considered to be undesirable, nor illegal. Current state-of-the-art techniques, however, do not take such gender-neutral explanations into account and tend to overreact and actually start reverse discriminating, as we will show in this paper. Therefore, we introduce and analyze the refined notion of conditional non-discrimination in classifier design. We show that some of the differences in decisions across the sensitive groups can be explainable and are hence tolerable. Therefore, we develop methodology for quantifying the explainable discrimination and algorithmic techniques for removing the illegal discrimination when one or more attributes are considered as explanatory. Experimental evaluation on synthetic and real-world classification datasets demonstrates that the new techniques are superior to the old ones in this new context, as they succeed in

Towards explaining the speed of k-means

NARCIS (Netherlands)

Manthey, Bodo; van de Pol, Jan Cornelis; Raamsdonk, F.; Stoelinga, Mariëlle Ida Antoinette

2011-01-01

The $k$-means method is a popular algorithm for clustering, known for its speed in practice. This stands in contrast to its exponential worst-case running-time. To explain the speed of the $k$-means method, a smoothed analysis has been conducted. We sketch this smoothed analysis and a generalization

Hawaii Energy Resource Overviews. Volume 3. Hawaiian ecosystem and its environmental determinants with particular emphasis on promising areas for geothermal development

Energy Technology Data Exchange (ETDEWEB)

Siegel, S.M.

1980-06-01

A brief geobiological history of the Hawaiian Islands is presented. Climatology, physiography, and environmental degradation are discussed. Soil types and associations, land use patterns and ratings, and vegetation ecology are covered. The fauna discussed include: ancient and recent vertebrate life, land mollusca, marine fauma, and insect fauna. (MHR)

Physico-chemical characteristics and abundance of aquatic ...

African Journals Online (AJOL)

Macroinvertebrates abundance shows that, out of the total number of species identified, 14 were arthropods, distributed among 3 classes; 10 species were of class Insecta, 2 species from class Arachnida and 2 species from the class Crustacean. Phylum Mollusca and phylum Annelida had 2 and 1 species, respectively.

The evolution of shell form in tropical terrestrial microsnails

NARCIS (Netherlands)

Liew, Thor Seng

2014-01-01

Mollusca form an important animal phylum that first appeared in the Cambrian, and today is,after Arthropoda, the second largest animal phylum, with more than 100,000 extant species(Bieler, 1992, Brusca and Brusca, 2003), with the class Gastropoda accounting for 80% of the extant species in the

Variación estacional de la composición proximal del mejillón Tagelus peruvianus (Bivalvia: Solecurtidae del Golfo de Nicoya, Puntarenas, Costa Rica

Directory of Open Access Journals (Sweden)

Cristian Fonseca Rodríguez

2011-12-01

Full Text Available La extracción del mejillón Tagelus peruvianus representa una actividad económica complementaria de los pescadores artesanales, es una de las especies de mayor pesca y consumo ya que son una fuente importante de proteína, minerales y vitaminas esenciales para la población humana. Por lo tanto, se estudió la variación estacional de su composición proximal, índice de condición y contenido energético. Mensualmente, entre noviembre de 2007 y octubre de 2008, se recolectaron de 35 a 40 especímenes. La composición proximal se determinó siguiendo la metodología recomendada por la AOAC. Los resultados mostraron que el índice de condición disminuyó en los meses de diciembre, enero y mayo, lo que indica que hay dos periodos de desove y una fase de reposo gonadal. El componente principal del mejillón es la proteína (61.9±4.3%, seguido de carbohidratos (15.7±2.4%, cenizas (14.0±1.9% y lípidos (8.5±1.7%. El contenido calórico promedio fue de 5.0±0.1kcal/g. La disminución en los valores de proteínas, lípidos y calorías coinciden con los periodos de desove. Se puede concluir que T. peruvianus presenta valores nutricionales óptimos para el consumo humano, por su bajo contenido de grasa y su aceptable contenido proteico.Seasonal variation in proximate composition of mussels Tagelus peruvianus (Bivalvia: Solecurtidae from the Gulf of Nicoya, Puntarenas, Costa Rica. Marine bivalves are a very important food source for human consumption, and species that has not been of traditional use as a fishery resource are gaining interest. Seasonal variation in proximate composition, condition index and energy or caloric content of the mussel Tagelus peruvianus were studied in the Gulf of Nicoya, Puntarenas, Costa Rica. From November 2007 to October 2008, a total of 35 to 40 specimens per month were collected. The proximate composition using the AOAC methods was determined. Results showed that the condition index during December, January and May

The Calyptogena magnifica chemoautotrophic symbiont genome

Energy Technology Data Exchange (ETDEWEB)

Newton, I.L.; Woyke, T.; Auchtung, T.A.; Dilly, G.F.; Dutton,R.J.; Fisher, M.C.; Fontanez, K.M.; Lau, E.; Stewart, F.J.; Richardson,P.M.; Barry, K.W.; Saunders, E.; Detter, J.C.; Wu, D.; Eisen, J.A.; Cavanaugh, C.M.

2007-03-01

Chemoautotrophic endosymbionts are the metabolic cornerstone of hydrothermal vent communities, providing invertebrate hosts with nearly all of their nutrition. The Calyptogena magnifica (Bivalvia: Vesicomyidae) symbiont, Candidatus Ruthia magnifica, is the first intracellular sulfur-oxidizing endosymbiont to have its genome sequenced, revealing a suite of metabolic capabilities. The genome encodes major chemoautotrophic pathways as well as pathways for biosynthesis of vitamins, cofactors, and all 20 amino acids required by the clam.

Firm Performance and Comply or Explain Disclosure in Corporate Governance

DEFF Research Database (Denmark)

Rose, Caspar

2016-01-01

This study investigates the degree of Danish firm adherence to the Danish Code of Corporate Governance and analyzes if a higher degree of comply or explain disclosure is related to firm performance. This article formulates a methodology for quantifying the degree of comply or explain disclosure...... there is no impact on performance when increasing compliance with the recommendations on risk management and internal controls. This article demonstrates that these three areas are the ones where Danish firms show the lowest degree of comply or explain disclosure, although the overall adherence to the Danish code...... that soft law may be an efficient way of increasing the quality of corporate governance among listed firms. However, in order to strengthen investor confidence, national code authorities/committees should be more active in penalizing poor explanations as well as cases where firms wrongfully state...

Fresh-Water Mussels (Mollusca: Bivalvia: Unionidae) of the Upper Mississippi River: Observations at Selected Sites within the 9-Foot Channel Navigation Project on Behalf of the U.S. Army.

Science.gov (United States)

1978-06-16

Deertoe Ohovaria olivaria *Hjckorynut Glassback Eggshell Long ’Solid Actinonaias carinata *Mucket Mouket Mougat A. elipsiformie *Ellipse Liqumia recta...Catservatuls end Iited States Nepartmet of Agriculture, Soil Ctsraemtioa Service, Jeferson City* Missourl. Pp. I-ISO. Seshoala, A. V. 1941. Tapoles as

Annotations to the figured scallops (Mollusca, Bivalvia, Pectinidae) in Gualtieri’s “Index Testarum Conchyliorum”, deposited in the Museo di Storia Naturale e del Territorio at Calci (Pisa, Italy)

NARCIS (Netherlands)

Dijkstra, H.H.

2016-01-01

An overview is given of the Pectinidae types present in the Gualtieri collection. In Gualtieri (1742) 46 figures (pl. 73 - 15 figs, pl. 74 - 25 figs, pl. 98 – 2 figs, and pl. 99 – 4 figs) show specimens of Pectinidae. Linnaeus (1758) referred to 10 Pectinidae species figured by Gualtieri. Of these,

Ciclo gametogênico e comportamento reprodutivo de Iphigenia brasiliana (Mollusca, Bivalvia, Donacidae no estuário do rio Subaé, Baía de Todos os Santos, Bahia, Brasil

Directory of Open Access Journals (Sweden)

Patrícia P. Silva

Full Text Available Este estudo teve como objetivos descrever o ciclo gametogênico e o comportamento reprodutivo da população de Iphigenia brasiliana (Lamarck,1818 no estuário do rio Subaé, Baía de Todos os Santos, Bahia. Os bivalves foram coletados de novembro de 2001 a novembro de 2002. Um total de 244 espécimes foi medido (eixo anteroposterior, eviscerado, fixado, desidratado e incluído em parafina. O estudo histológico das gônadas foi realizado através de cortes seriados do tecido gonadal, de 5 mm de espessura, e corados pela HE. O tamanho médio mínimo da primeira maturação sexual (Lpm foi estimado a partir da distribuição das frequências relativas de jovens e adultos, por classe de comprimento dos indivíduos. As frequências relativas dos sexos em cada estádio de desenvolvimento foram consideradas conjuntamente para a análise do comportamento reprodutivo da população, e, em separado, para avaliar a sincronia do ciclo sexual entre machos e fêmeas. Foi observada uma variação de tamanhos entre 9,1 e 66,6 mm, com comprimento médio de 50,2 mm. O estudo não demonstrou diferença significativa entre os tamanhos de machos e fêmeas. Não foi possível observar a diferenciação de sexos em 2,1% dos indivíduos analisados. 51,6% dos indivíduos foram identificados como machos (M e 46,3% como fêmeas (F, não sendo constatadas diferenças significativas entre o número médio de machos e fêmeas, resultando numa proporção de M:F de 1,1:1. O Lpm foi estimado em 11,4 mm, mas apenas ao alcançarem comprimento médio de 34,4 mm, todos os indivíduos foram considerados adultos. Foram caracterizados quatro estádios de evolução do desenvolvimento gonadal em fêmeas e machos. A análise dos diferentes estádios permitiu a observação dos fenômenos de atresia e inversão sexual em fêmeas. O ciclo reprodutivo apresentou eliminação contínua de gametas, com maiores intensidades reprodutivas nos meses de novembro de 2001 a abril de 2002 e, também, no mês de outubro de 2002.

Adaptive hatching hypotheses do not explain asynchronous ...

African Journals Online (AJOL)

At the core of the suite of adaptive hatching hypotheses advanced to explain asynchronous hatching in birds is the assumption that if food is not limited then all the hatchlings will develop normally to adulthood. In this study Brown-headed Parrot Poicephalus cryptoxanthus chicks were hand fed and weighed on a daily basis.

Spatially tuned normalization explains attention modulation variance within neurons.

Science.gov (United States)

Ni, Amy M; Maunsell, John H R

2017-09-01

Spatial attention improves perception of attended parts of a scene, a behavioral enhancement accompanied by modulations of neuronal firing rates. These modulations vary in size across neurons in the same brain area. Models of normalization explain much of this variance in attention modulation with differences in tuned normalization across neurons (Lee J, Maunsell JHR. PLoS One 4: e4651, 2009; Ni AM, Ray S, Maunsell JHR. Neuron 73: 803-813, 2012). However, recent studies suggest that normalization tuning varies with spatial location both across and within neurons (Ruff DA, Alberts JJ, Cohen MR. J Neurophysiol 116: 1375-1386, 2016; Verhoef BE, Maunsell JHR. eLife 5: e17256, 2016). Here we show directly that attention modulation and normalization tuning do in fact covary within individual neurons, in addition to across neurons as previously demonstrated. We recorded the activity of isolated neurons in the middle temporal area of two rhesus monkeys as they performed a change-detection task that controlled the focus of spatial attention. Using the same two drifting Gabor stimuli and the same two receptive field locations for each neuron, we found that switching which stimulus was presented at which location affected both attention modulation and normalization in a correlated way within neurons. We present an equal-maximum-suppression spatially tuned normalization model that explains this covariance both across and within neurons: each stimulus generates equally strong suppression of its own excitatory drive, but its suppression of distant stimuli is typically less. This new model specifies how the tuned normalization associated with each stimulus location varies across space both within and across neurons, changing our understanding of the normalization mechanism and how attention modulations depend on this mechanism. NEW & NOTEWORTHY Tuned normalization studies have demonstrated that the variance in attention modulation size seen across neurons from the same cortical

Do sector-specific shocks explain aggregate fluctuations?

DEFF Research Database (Denmark)

Busato, Francesco; Girardi, Alessandro; Argentiero, Amedeo

-sector productivity fluctuations.(ii) Cross-sector technology shocks have very little explanatory power on productivity andemployment, while cross-sector non-technology shocks explain more than 60 percent of employmentthat is reallocated across sector; this suggests that the shocks’ transmission mechanism....... Thenon-durable sector may follow a standard RBC model, while the durable sector should incorporateconsumption habit formation....

Explaining probalistic risk assessment in common language

International Nuclear Information System (INIS)

Wong, J.W.

1994-01-01

Probabilistic human health risk assessment is explained in ordinary language using a hypothetical example and the ingestion equation from EPA's Risk Assessment Guidance for Superfund. A section on understanding probabilities and probability distributions used in a Monte Carlo simulation is included as well as an appendix showing the computer run and the technical assumptions behind it

Can the inherence heuristic explain vitalistic reasoning?

Science.gov (United States)

Bastian, Brock

2014-10-01

Inherence is an important component of psychological essentialism. By drawing on vitalism as a way in which to explain this link, however, the authors appear to conflate causal explanations based on fixed features with those based on general causal forces. The disjuncture between these two types of explanatory principles highlights potential new avenues for the inherence heuristic.

Explaining Violence in Sierra Leone's Civil War

African Journals Online (AJOL)

Explaining the violence of civil war is never a simple task for the scholar. In the case of the Sierra Leone, paradoxically, the task has in some ways been rendered more difficult by the sheer variety of compelling scholarship on the question. This paper seeks to identify the most useful of the explanations offered thus far, and ...

WAP explained

International Nuclear Information System (INIS)

Kaiser, M.J.; Pulsipher, A.G.

2004-01-01

The Weatherization Assistance Program (WAP) is a federal block grant program administered by all 50 states and the District of Columbia through community action agencies, state energy offices, local government, and other nonprofit organizations to provide weatherization services to eligible households. The WAP was established in 1976 to increase the energy efficiency, reduce the energy expenditures, and improve the health and safety of low-income households, especially those households that are particularly vulnerable such as families with children, persons with disabilities, and the elderly. The manner in which WAP funds have been allocated to states, however, has been a contentious issue since the inception of the program. Southern states have argued that too much of the federal funding goes to cold-climate and rural states. Northern states disagree. In 1990, Congress amended the Energy Conservation and Production Act and required the Department of Energy to develop a new funding formula. The Department of Energy currently uses a three-factor formula developed in 1995 in conjunction with a two-factor formula developed in 1977 and a hold-harmless provision to allocate WAP funding. The purpose of this paper is to explain the WAP allocation mechanism and the assumptions associated with the 1977 and the 1995 funding formula. The factors that compose each funding formula are critically assessed and various implementation issues are reviewed, including the selection of the trigger point and program capacity levels. It is not possible to define the need for weatherization assistance objectively and in a unique manner, and this ambiguity is the main reason why the WAP allocation mechanism is expected to remain a lively topic of debate and contention

IEE wiring regulations explained and illustrated

CERN Document Server

Scaddan, Brian

2013-01-01

The IEE Wiring Regulations Explained and Illustrated, Second Edition discusses the recommendations of the IEE Regulations for the Electrical Equipment of Buildings for the safe selection or erection of wiring installations. The book emphasizes earthing, bonding, protection, and circuit design of electrical wirings. The text reviews the fundamental requirements for safety, earthing systems, the earth fault loop impedance, and supplementary bonding. The book also describes the different types of protection, such as protection against mechanical damage, overcurrent, under voltage (which prevents

k-essence explains a Lorentz violation experiment

International Nuclear Information System (INIS)

Li Miao; Pang Yi; Wang Yi

2009-01-01

Recently, a state of the art experiment shows evidence for Lorentz violation in the gravitational sector. To explain this experiment, we investigate a spontaneous Lorentz violation scenario with a generalized scalar field. We find that when the scalar field is nonminimally coupled to gravity, the Lorentz violation induces a deformation in the Newtonian potential along the direction of Lorentz violation.

The natural selection of metabolism explains curvature in allometric scaling

OpenAIRE

Witting, Lars

2016-01-01

I simulate the evolution of metabolism and mass to explain the curvature in the metabolic allometry for placental and marsupial mammals. I assume that the release of inter-specific competition by the extinction of dinosaurs 65 million years ago made it possible for each clade to diversity into a multitude of species across a wide range of niches. The natural selection of metabolism and mass was then fitted to explain the maximum observed body masses over time, as well as the current inter-spe...

Explaining the judicial independence of international courts: a comparative analysis

DEFF Research Database (Denmark)

Beach, Derek

What factors allow some international courts (ICs) to rule against the express preferences of powerful member states, whereas others routinely defer to governments? While judicial independence is not the only factor explaining the strength of a given international institution, it is a necessary...... condition. The paper first develops three sets of competing explanatory variables that potentially can explain variations in the judicial independence of ICs. The causal effects of these explanatory variables upon variance in judicial independence are investigated in a comparative analysis of the ACJ, ECJ...

Explaining  the choice of accounting standards in municipal corporations

OpenAIRE

Collin, Sven-Olof; Tagesson, Torbjörn; Andersson, Anette; Cato, Josefine; Hansson, Karin

2004-01-01

Positive  accounting  theory  (PAT)  tries  to  explain  corporations’  choices  of accounting standards. Empirical research in this field has been focused on the choices  made by large, listed corporations. We challenge this grounding through extending the empirical domain by testing PAT on Swedish municipal corporations. In  order to be able to explain the choice of accounting standards in municipal corporations, PAT has to be complemented by institutional factors that can consider the   fo...

Cultural values: can they explain self-reported health?

NARCIS (Netherlands)

Roudijk, B.; Donders, R.; Stalmeier, P.F.

2017-01-01

PURPOSE: Self-reported health (SRH) is a measure widely used in health research and population studies. Differences in SRH have been observed between countries and cultural values have been hypothesized to partly explain such differences. Cultural values can be operationalized by two cultural

From laggard to leader: Explaining offshore wind developments in the UK

International Nuclear Information System (INIS)

Kern, Florian; Smith, Adrian; Shaw, Chris; Raven, Rob; Verhees, Bram

2014-01-01

Offshore wind technology has recently undergone rapid deployment in the UK. And yet, up until recently, the UK was considered a laggard in terms of deploying renewable energy. How can this burst of offshore wind activity be explained? An economic analysis would seek signs for newfound competitiveness for offshore wind in energy markets. A policy analysis would highlight renewable energy policy developments and assess their contribution to economic prospects of offshore wind. However, neither perspective sheds sufficient light on the advocacy of the actors involved in the development and deployment of the technology. Without an account of technology politics it is hard to explain continuing policy support despite rising costs. By analysing the actor networks and narratives underpinning policy support for offshore wind, we explain how a fairly effective protective space was constructed through the enroling of key political and economic interests. - Highlights: • UK is world leader in offshore wind deployment. • Article explains boom in deployment by looking at the politics of renewable energy policy. • Offshore wind is supported by a variety of actors with aligned political and economic interests. • Analysis highlights the importance of a system builder

Matlab for engineers explained

CERN Document Server

Gustafsson, Fredrik

2003-01-01

This book is written for students at bachelor and master programs and has four different purposes, which split the book into four parts: 1. To teach first or early year undergraduate engineering students basic knowledge in technical computations and programming using MATLAB. The first part starts from first principles and is therefore well suited both for readers with prior exposure to MATLAB but lacking a solid foundational knowledge of the capabilities of the system and readers not having any previous experience with MATLAB. The foundational knowledge gained from these interactive guided tours of the system will hopefully be sufficient for an effective utilization of MATLAB in the engineering profession, in education and in research. 2. To explain the foundations of more advanced use of MATLAB using the facilities added the last couple of years, such as extended data structures, object orientation and advanced graphics. 3. To give an introduction to the use of MATLAB in typical undergraduate courses in elec...

Explaining labor wedge trends: An equilibrium search approach

Directory of Open Access Journals (Sweden)

Coralia A. Quintero Rojas

2016-06-01

Full Text Available In this paper, we present a search and matching model of the labor market and use this as a device to explain the long-run variation in the aggregate hours worked in several OECD countries over the period 1980-2013. The model distinguishes between hours worked per employee (intensive margin and the employment rate (extensive margin and includes a tax/benefit system. This allows us to assess the impact of the observed time-varying heterogeneity of taxes, unemployment benefits, and workers’ bargaining power on the two margins. Our method is based on an accounting procedure. Once it has been calibrated, we find that, for the ten countries of the sample, our search economy is able to explain the patterns of the two margins of aggregate hours worked over the 1980-2013 period, when it includes the cross-country heterogeneity of the labor market institutions.

Defense styles explain psychiatric symptoms: an empirical study.

Science.gov (United States)

Holi, M M; Sammallahti, P R; Aalberg, V A

1999-11-01

To examine the relation between psychiatric symptoms and defense mechanisms, we administered two questionnaires, the Symptom Check-list 90 (SCL-90) and the Defense Style Questionnaire (DSQ) to 122 psychiatric out-patients and to a community sample of 337 subjects. Using regression analysis, we found that 51.8% of the variation in subject's Global Severity Index value could be explained by his defense style. Of the three defense styles, the immature style explained most of the variation in the symptoms. We found little overall evidence for specific connections between particular defenses and symptoms. Projection and dissociation were central in most of the symptom dimensions. We compared patients and controls with the same level of general symptom severity and found that patients used significantly more devaluation and splitting, and controls used significantly more altruism and idealization. Whether defenses predispose to certain symptomatology or are one of its aspects is discussed.

Evaluation of the potential of translocated common cockle for ecological risk assessment studies: bioaccumulation and biomarkers test

OpenAIRE

Arteaga, Jorge Lobo

2009-01-01

Thesis submitted to the Faculdade de Ciências e Tecnologia to obtain the Master’s degree in Environmental Engineering, profile in Ecological Engineering Sediment–bound contamination is a major concern factor in estuaries and other confined coastal water bodies, frequently subjected to anthropogenic sources of pollution. In order to investigate the effects and responses of the common cockle (Cerastoderma edule, L. 1558, Bivalvia: Cardiidae) to sediment contaminants and to assess the species...

Phylogeny, phylogeography, and evolution in the Mediterranean region: News from a freshwater mussel (Potomida, Unionida)

OpenAIRE

Froufe, Elsa; Prié, Vincent; Faria, João; Ghamizi, Mohamed; Gonçalves, Duarte V.; Gürlek, Mustafa Emre; Karaouzas, Ioannis; Kebapçi, Ümit; Şereflişan, Hülya; Sobral, Carina; Sousa, Ronaldo; Teixeira, Amílcar; Varandas, Simone; Zogaris, Stamatis; Lopes-Lima, Manuel

2016-01-01

The Potomida genus (Bivalvia, Unionida) has a Circum-Mediterranean distribution and like other freshwater mussel species, its populations have suffered dramatic declines. Although this genus is currently considered as monotypic, it has a long history of taxonomic revisions and presently many aspects of its systematics and evolutionary history are unclear. We sampled a total of 323 individuals from 39 different sites across the Potomida genus distribution, and sequenced two mitochondrial (16S ...

Fundamental volatility and stock returns : does fundamental volatility explain stock returns?

OpenAIRE

Selboe, Guner K.; Virdee, Jaspal Singh

2017-01-01

In this thesis, we investigate whether the fundamental uncertainty can explain the crosssection of stock returns. To measure the fundamental uncertainty, we estimate rolling standard deviations and accounting betas of four different fundamentals: revenues, gross profit, earnings and cash flows. The standard deviation and the beta of revenues significantly explain returns in the Fama-Macbeth procedure, but only appears significant among smaller stocks in the portfolio formation ...

EXPLAINING THE ASSOCIATION BETWEEN INCARCERATION AND DIVORCE*

Science.gov (United States)

Siennick, Sonja E.; Stewart, Eric A.; Staff, Jeremy

2014-01-01

Recent studies have suggested that incarceration dramatically increases the odds of divorce, but we know little about the mechanisms that explain the association. This study uses prospective longitudinal data from a subset of married young adults in the National Longitudinal Study of Adolescent Health (N = 1,919) to examine whether incarceration is associated with divorce indirectly via low marital love, economic strain, relationship violence, and extramarital sex. The findings confirmed that incarcerations occurring during, but not before, a marriage were associated with an increased hazard of divorce. Incarcerations occurring during marriage also were associated with less marital love, more relationship violence, more economic strain, and greater odds of extramarital sex. Above-average levels of economic strain were visible among respondents observed preincarceration, but only respondents observed postincarceration showed less marital love, more relationship violence, and higher odds of extramarital sex than did respondents who were not incarcerated during marriage. These relationship problems explained approximately 40 percent of the association between incarceration and marital dissolution. These findings are consistent with theoretical predictions that a spouse’s incarceration alters the rewards and costs of the marriage and the relative attractiveness of alternative partners. PMID:25598544

Ciclo reproductivo del ostión de manglar Crassostrea rhizophorae (Bivalvia: Ostreidae en la Bahía de Camamu, Bahia, Brasil

Directory of Open Access Journals (Sweden)

Tiago Lenz

2011-03-01

Full Text Available El ostión de manglar es un importante recurso pesquero que se distribuye por toda la costa brasileña y una de las especies nativas con mayor potencial para maricultura. Este estudio tuvo como objetivo conocer las características reproductivas del ostión de manglar Crassostrea rhizophorae en el estero del Río Maraú, Bahía de Camamu, Bahia, Brasil. Las muestras fueran recolectadas mensualmente, entre agosto de 2006 y septiembre de 2007, en dos sitios. Las metodologías utilizadas fueron el análisis histológico de las gónadas y el cálculo de rendimiento de carne. La temperatura del agua durante el período de estudio varió de 23.5°C a 30°C y la salinidad osciló entre 15 y 35ups. La altura de los ostiones examinados varió de 27 a 102mm (n=437. Hubo predominancia de hembras en las poblaciones de ambos sitios. Los análisis de estadios gonádicos demostraron que el proceso de reproducción de C. rhizophorae en el estero del Río Maraú es continuo durante el año, sin período de reposo sexual. El rendimiento de carne (R fue de 8.0% a 17.7% (n=669. Los resultados de este estudio proveen informaciones para la captación de semilla e implantación de la ostricultura en la Bahía de Camamu.Reproductive cycle of the mangrove oyster Crassostrea rhizophorae (Bivalvia: Ostreidae in Camamu Bay, Bahia, Brasil. The mangrove oyster Crassostrea rhizophorae is important fishery resource along the entire Brasilian coast with excellent potential for marine culture. The purpose of this paper was to examine the reproductive characteristics of the oyster of the Maraú river estuary in Camamu Bay, Bahia, Brasil. The samples were collected monthly, from September 2006 to August 2007, at two points (I and II in Camamu Bay. At each site 20 oysters were collected for histological analysis, fixed in Davidson’s solution, embedded in paraffin, dehydrated in an ethanol series, sectioned (7μm thick and stained with Harris hematoxylin and Eosin (HE

Explaining the Origins and Expansion of Mass Education.

Science.gov (United States)

Boli, John; And Others

1985-01-01

Theories of mass education that emphasize processes of differentiation or the reproduction of inequalities ignore the universal and institutional character of mass education. A theoretical framework emphasizing individualism and the rationalization of individual and collective authority better explains the relationship of mass education to…

Thermally-assisted Magma Emplacement Explains Restless Calderas

Science.gov (United States)

Amoruso, A.; Crescentini, L.; D'Antonio, M.; Acocella, V.

2017-12-01

Many calderas show repeated unrest over centuries. Though probably induced by magma, this unique behaviour is not understood and its dynamics remains elusive. To better understand these restless calderas, we interpret deformation data and build thermal models of Campi Flegrei, Italy, which is the best-known, yet most dangerous calderas, lying to the west of Naples and restless since the 1950s at least.Our elaboration of the geodetic data indicates that the inflation and deflation of magmatic sources at the same location explain most deformation, at least since the build-up of the last 1538 AD eruption. However, such a repeated magma emplacement requires a persistently hot crust.Our thermal models show that the repeated emplacement was assisted by the thermal anomaly created by magma that was intruded at shallow depth 3 ka before the last eruption and, in turn, contributed to maintain the thermal anomaly itself. This may explain the persistence of the magmatic sources promoting the restless behaviour of the Campi Flegrei caldera; moreover, it explains the crystallization, re-melting and mixing among compositionally distinct magmas recorded in young volcanic rocks.Available information at other calderas highlights similarities to Campi Flegrei, in the pattern and cause of unrest. All monitored restless calderas have either geodetically (Yellowstone, Aira Iwo-Jima, Askja, Fernandina and, partly, Long Valley) or geophysically (Rabaul, Okmok) detected sill-like intrusions inducing repeated unrest. Some calderas (Yellowstone, Long Valley) also show stable deformation pattern, where inflation insists on and mimics the resurgence uplift. The common existence of sill-like sources, also responsible for stable deformation patterns, in restless calderas suggests close similarities to Campi Flegrei. This suggests a wider applicability of our model of thermally-assisted sill emplacement, to be tested by future studies to better understand not only the dynamics of restless

The Role of Secondary Education in Explaining Competitiveness

Science.gov (United States)

Baumann, Chris; Winzar, Hume

2016-01-01

The literature establishes that education drives economic performance, but the extent that education is associated with a country's competitiveness is empirically untested. Our study analyses Programme for International Student Assessment (PISA) data from 63 countries to ascertain education's role in explaining the competitiveness of a country.…

The Effect of Self-Explaining on Robust Learning

Science.gov (United States)

Hausmann, Robert G. M.; VanLehn, Kurt

2010-01-01

Self-explaining is a domain-independent learning strategy that generally leads to a robust understanding of the domain material. However, there are two potential explanations for its effectiveness. First, self-explanation generates additional "content" that does not exist in the instructional materials. Second, when compared to…

Juvenile Delinquency Explained? A Test of Containment Theory.

Science.gov (United States)

Thompson, William E.; Dodder, Richard A.

1983-01-01

Examines the extent to which variation in self-reported delinquency is explained by the seven containment variables (favorable self-concept, goal orientation, frustration tolerance, retention of norms, internalization of rules, availability of meaningful roles, and group reinforcement), and focuses on racial and sex differences in self-reported…

Functional traits explain ecosystem function through opposing mechanisms.

Science.gov (United States)

Cadotte, Marc W

2017-08-01

The ability to explain why multispecies assemblages produce greater biomass compared to monocultures, has been a central goal in the quest to understand biodiversity effects on ecosystem function. Species contributions to ecosystem function can be driven by two processes: niche complementarity and a selection effect that is influenced by fitness (competitive) differences, and both can be approximated with measures of species' traits. It has been hypothesised that fitness differences are associated with few, singular traits while complementarity requires multidimensional trait measures. Here, using experimental data from plant assemblages, I show that the selection effect was strongest when trait dissimilarity was low, while complementarity was greatest with high trait dissimilarity. Selection effects were best explained by a single trait, plant height. Complementarity was correlated with dissimilarity across multiple traits, representing above and below ground processes. By identifying the relevant traits linked to ecosystem function, we obtain the ability to predict combinations of species that will maximise ecosystem function. © 2017 John Wiley & Sons Ltd/CNRS.

Tuned Normalization Explains the Size of Attention Modulations

Science.gov (United States)

Ni, Amy M.; Ray, Supratim; Maunsell, John H. R.

2012-01-01

SUMMARY The effect of attention on firing rates varies considerably within a single cortical area. The firing rate of some neurons is greatly modulated by attention while others are hardly affected. The reason for this variability across neurons is unknown. We found that the variability in attention modulation across neurons in area MT of macaques can be well explained by variability in the strength of tuned normalization across neurons. The presence of tuned normalization also explains a striking asymmetry in attention effects within neurons: when two stimuli are in a neuron’s receptive field, directing attention to the preferred stimulus modulates firing rates more than directing attention to the non-preferred stimulus. These findings show that much of the neuron-to-neuron variability in modulation of responses by attention depends on variability in the way the neurons process multiple stimuli, rather than differences in the influence of top-down signals related to attention. PMID:22365552

[Pay for performance explained by transaction costs theory].

Science.gov (United States)

Gorbaneff, Yuri; Cortes, Ariel; Torres, Sergio; Yepes, Francisco

2011-01-01

To evaluate the ability of transaction costs theory to explain incentives in the health care chain. We performed a case study of CPS, a health insurance company in Bogota (Colombia), which preferred not to publish its name. CPS moves in the environment of high transaction costs and uses the hybrid form of governance at the outpatient level. Incentive intensity, administrative control and the contract all agree with the theory. At the hospital level, the market is used, despite greater uncertainty. Because of the discrete form (1.0) of the incentives and the absence of administrative control, it is difficult for CPS to relate payment to hospital performance. Transaction costs theory explains the configuration of incentives. Another contribution made by this theory to the literature is the criterion to differentiate between the market and the hybrid. We propose that the market uses discrete-type (1.0) incentives, while the hybrid uses continuous, commission-like incentives. Copyright © 2011 SESPAS. Published by Elsevier Espana. All rights reserved.

Tuned normalization explains the size of attention modulations.

Science.gov (United States)

Ni, Amy M; Ray, Supratim; Maunsell, John H R

2012-02-23

The effect of attention on firing rates varies considerably within a single cortical area. The firing rate of some neurons is greatly modulated by attention while others are hardly affected. The reason for this variability across neurons is unknown. We found that the variability in attention modulation across neurons in area MT of macaques can be well explained by variability in the strength of tuned normalization across neurons. The presence of tuned normalization also explains a striking asymmetry in attention effects within neurons: when two stimuli are in a neuron's receptive field, directing attention to the preferred stimulus modulates firing rates more than directing attention to the nonpreferred stimulus. These findings show that much of the neuron-to-neuron variability in modulation of responses by attention depends on variability in the way the neurons process multiple stimuli, rather than differences in the influence of top-down signals related to attention. Copyright © 2012 Elsevier Inc. All rights reserved.

Content-Free Computer Supports for Self-Explaining: Modifiable Typing Interface and Prompting

Science.gov (United States)

Chou, Chih-Yueh; Liang, Hung-Ta

2009-01-01

Self-explaining, which asks students to generate explanations while reading a text, is a self-constructive activity and is helpful for students' learning. Studies have revealed that prompts by a human tutor promote students' self-explanations. However, most studies on self-explaining focus on spoken self-explanations. This study investigates the…

Ecology of benthic production in the coastal zone of Goa

Digital Repository Service at National Institute of Oceanography (India)

Harkantra, S.N.; Parulekar, A.H.

was comprised of Polychaeta (58.5%), Mollusca (18.1%), Crustacea (9.1%), Echinodermata (7.1%) and other minor taxa (7.3%) Population count and biomass varied from 25 to 7823 m-2 (X- = 1256 m-2) and 0.2 to 2251.25 g m-2 (X- = 67.07 g m-2) respectively The higher...

On the explaining-away phenomenon in multivariate latent variable models.

Science.gov (United States)

van Rijn, Peter; Rijmen, Frank

2015-02-01

Many probabilistic models for psychological and educational measurements contain latent variables. Well-known examples are factor analysis, item response theory, and latent class model families. We discuss what is referred to as the 'explaining-away' phenomenon in the context of such latent variable models. This phenomenon can occur when multiple latent variables are related to the same observed variable, and can elicit seemingly counterintuitive conditional dependencies between latent variables given observed variables. We illustrate the implications of explaining away for a number of well-known latent variable models by using both theoretical and real data examples. © 2014 The British Psychological Society.

Explaining formation of Astronomical Jets using Dynamic Universe Model

Science.gov (United States)

Naga Parameswara Gupta, Satyavarapu

2016-07-01

Astronomical jets are observed from the centres of many Galaxies including our own Milkyway. The formation of such jet is explained using SITA simulations of Dynamic Universe Model. For this purpose the path traced by a test neutron is calculated and depicted using a set up of one densemass of the mass equivalent to mass of Galaxy center, 90 stars with similar masses of stars near Galaxy center, mass equivalents of 23 Globular Cluster groups, 16 Milkyway parts, Andromeda and Triangulum Galaxies at appropriate distances. Five different kinds of theoretical simulations gave positive results The path travelled by this test neutron was found to be an astronomical jet emerging from Galaxy center. This is another result from Dynamic Universe Model. It solves new problems like a. Variable Mass Rocket Trajectory Problem b. Explaining Very long baseline interferometry (VLBI) observations c. Astronomical jets observed from Milkyway Center d. Prediction of Blue shifted Galaxies e. Explaining Pioneer Anomaly f. Prediction of New Horizons satellite trajectory etc. Dynamic Universe Model never reduces to General relativity on any condition. It uses a different type of mathematics based on Newtonian physics. This mathematics used here is simple and straightforward. As there are no differential equations present in Dynamic Universe Model, the set of equations give single solution in x y z Cartesian coordinates for every point mass for every time step

Natural Diet of Callinectes ornatus Ordway, 1863 (Decapoda, Portunidae in the Itapocoroy Inlet, Penha, SC, Brazil

Directory of Open Access Journals (Sweden)

Joaquim Olinto Branco

2002-03-01

Full Text Available From January to December 1995, 332 individuals of the Callinectes ornatus species were collected from the Itapocoroy inlet in Penha, Sta. Catarina, Brazil to study its natural diet and the seasonal variations of diet. Results showed a diversified trophic spectrum with a generalized dietary strategy comprising the algae, macrophyta, foraminiferida, mollusca, polychaeta, crustacea, echinodermata, Osteichthyes and NIOM (Nonidentified Organic Matter groups.Alimentação natural de Callinectes ornatus Ordway, 1863 (Decapoda, Portunidae na Armação do Itapocoroy, Penha, SC - Brasil. No período de janeiro a dezembro de 1995, foram coletados 332 indivíduos de Callinectes ornatus, procedentes da Armação do Itapocoroy (Penha, SC. Foi estudada a alimentação natural da espécie e as variações sazonais da dieta. Os resultados mostram um espectro trófico diversificado, com estratégia alimentar generalista, sendo Algas, Macrófitas, Foraminiferida, Mollusca, Polychaeta, Crustacea, Echinodermata, Osteichthyes e matéria orgânica não identificada, os grupos que compõem sua dieta.

Density, size structure, shell orientation and epibiontic colonization of the fan mussel Pinna nobilis L. 1758 (Mollusca: Bivalvia in three contrasting habitats in an estuarine area of Sardinia (W Mediterranean

Directory of Open Access Journals (Sweden)

Piero Addis

2009-03-01

Full Text Available We investigated the spatial distribution, size structure, shell orientation and valve colonization by epibionts of the endangered Mediterranean bivalve Pinna nobilis in three continuous but different habitats in the Gulf of Oristano (Sardinia, western Mediterranean. The sampling stations chosen were: an estuarine area (E of coastal salt-marshes characterized by unvegetated sea-bottoms; and two areas in a seagrass meadow characterized by an extensive Posidonia oceanica meadow (Mw and patched mixed meadows of P. oceanica and Cymodocea nodosa (Me. We found significant differences in mean densities among stations and the highest value was found in the estuarine area. Shell orientation showed that there was uniform circular distribution of specimens in the Mw station and a unimodal distribution in the Me and E stations, where specimens were set at 0°N and 10°NNE, which is a pattern related to sea drift. Shell epibiosis displayed differences between habitats. The highest valve colonization was in the estuary, with filamentous dark algae and Ostrea edulis reaching almost 90 percent of shell coverage. This study provides new information on habitat preferences and data for assessing local populations of P. nobilis that is useful for its conservation and improving the knowledge of its ecology.

Use of environmental parameters to explain the variability in ...

African Journals Online (AJOL)

Abstract. This study attempts to explain the variability in recruitment of sardine in the northern Benguela and to develop potential models by including environmental information to predict recruitment. ... AJOL African Journals Online. HOW TO ...

Persistent villi hypoperfusion explains intramucosal acidosis in sheep endotoxemia

NARCIS (Netherlands)

Dubin, Arnaldo; Edul, Vanina Siham Kanoore; Pozo, Mario Omar; Murias, Gastón; Canullán, Carlos Manuel; Martins, Enrique Francisco; Ferrara, Gonzalo; Canales, Héctor Saul; Laporte, Mercedes; Estenssoro, Elisa; Ince, Can

2008-01-01

OBJECTIVE: To test the hypothesis that persistent villi hypoperfusion explains intramucosal acidosis after endotoxemic shock resuscitation. DESIGN: Controlled experimental study. SETTING: University-based research laboratory. SUBJECTS: A total of 14 anesthetized, mechanically ventilated sheep.

Plate-wide stress relaxation explains European Palaeocene basin inversions

DEFF Research Database (Denmark)

Nielsen, S.B.; Thomsen, Erik; Hansen, D.L.

2005-01-01

of the in-plane tectonic stress. The onset of relaxation inversions was plate-wide and simultaneous, and may have been triggered by stress changes caused by elevation of the North Atlantic lithosphere by the Iceland plume or the drop in NS convergence rate between Africa and Europe.......During Late Cretaceous and Cenozoic times many Paleozoic and Mesozoic rifts and basin structures in the interior of the European continent underwent several phases of inversion. The main phases occurred during the Late Cretaceous and Middle Paleocene, and have been explained by pulses...... Paleocene phase was characterized by domal uplift of a wider area with only mild fault movements, and formation of more distal and shallow marginal troughs. A simple flexural model explains how domal, secondary inversion follows inevitably from primary, convergence related inversion upon relaxation...

Explaining the harmonic sequence paradox.

Science.gov (United States)

Schmidt, Ulrich; Zimper, Alexander

2012-05-01

According to the harmonic sequence paradox, an expected utility decision maker's willingness to pay for a gamble whose expected payoffs evolve according to the harmonic series is finite if and only if his marginal utility of additional income becomes zero for rather low payoff levels. Since the assumption of zero marginal utility is implausible for finite payoff levels, expected utility theory - as well as its standard generalizations such as cumulative prospect theory - are apparently unable to explain a finite willingness to pay. This paper presents first an experimental study of the harmonic sequence paradox. Additionally, it demonstrates that the theoretical argument of the harmonic sequence paradox only applies to time-patient decision makers, whereas the paradox is easily avoided if time-impatience is introduced. ©2011 The British Psychological Society.

Deep supervised, but not unsupervised, models may explain IT cortical representation.

Directory of Open Access Journals (Sweden)

Seyed-Mahdi Khaligh-Razavi

2014-11-01

Full Text Available Inferior temporal (IT cortex in human and nonhuman primates serves visual object recognition. Computational object-vision models, although continually improving, do not yet reach human performance. It is unclear to what extent the internal representations of computational models can explain the IT representation. Here we investigate a wide range of computational model representations (37 in total, testing their categorization performance and their ability to account for the IT representational geometry. The models include well-known neuroscientific object-recognition models (e.g. HMAX, VisNet along with several models from computer vision (e.g. SIFT, GIST, self-similarity features, and a deep convolutional neural network. We compared the representational dissimilarity matrices (RDMs of the model representations with the RDMs obtained from human IT (measured with fMRI and monkey IT (measured with cell recording for the same set of stimuli (not used in training the models. Better performing models were more similar to IT in that they showed greater clustering of representational patterns by category. In addition, better performing models also more strongly resembled IT in terms of their within-category representational dissimilarities. Representational geometries were significantly correlated between IT and many of the models. However, the categorical clustering observed in IT was largely unexplained by the unsupervised models. The deep convolutional network, which was trained by supervision with over a million category-labeled images, reached the highest categorization performance and also best explained IT, although it did not fully explain the IT data. Combining the features of this model with appropriate weights and adding linear combinations that maximize the margin between animate and inanimate objects and between faces and other objects yielded a representation that fully explained our IT data. Overall, our results suggest that explaining

Explainers' development of science-learner identities through participation in a community of practice

Science.gov (United States)

Richardson, Anne E.

The urgent environmental issues of today require science-literate adults to engage in business and political decisions to create solutions. Despite the need, few adults have the knowledge and skills of science literacy. This doctoral dissertation is an analytical case study examining the science-learner identity development of Exploratorium Field Trip Explainers. Located in San Francisco, CA, the Exploratorium is a museum of science, art, and human perception dedicated to nurturing curiosity and exploration. Data collected included semi-structured interviews with sixteen former Field Trip Explainers, participant observation of the current Field Trip Explainer Program, and review of relevant documentation. Data analysis employed constant comparative analysis, guided by the communities of practice theoretical framework (Wenger, 1998) and the National Research Council's (2009) Six Strands of Science Learning. Findings of this research indicate that Exploratorium Field Trip Explainers participate in a community of practice made up of a diverse group of people that values curiosity and openness to multiple ways of learning. Many participants entered the Field Trip Explainer Program with an understanding of science learning as a rigid process reserved for a select group of people; through participation in the Field Trip Explainer community of practice, participants developed an understanding of science learning as accessible and a part of everyday life. The findings of this case study have implications for research, theory, and practice in informal adult science learning, access of non-dominant groups to science learning, and adult workplace learning in communities of practice.

"Explaining the Gender Wage Gap in Georgia"

OpenAIRE

Tamar Khitarishvili

2009-01-01

This paper evaluates gender wage differentials in Georgia between 2000 and 2004. Using ordinary least squares, we find that the gender wage gap in Georgia is substantially higher than in other transition countries. Correcting for sample selection bias using the Heckman approach further increases the gender wage gap. The Blinder Oaxaca decomposition results suggest that most of the wage gap remains unexplained. The explained portion of the gap is almost entirely attributed to industrial variab...

Review of yield gap explaining factors and opportunities for alternative data collection approaches

NARCIS (Netherlands)

Beza, E.A.; Vasco Silva, João; Kooistra, Lammert; Reidsma, Pytrik

2017-01-01

Yield gap analysis is gaining increased scientific attention, as estimating and explaining yield gaps shows the potential for sustainable intensification of agricultural systems. Explaining yield gaps requires detailed information about the biophysical environment, crop management as well as

Pre-service primary school teachers’ abilities in explaining water and air pollution scientifically

Science.gov (United States)

Lukmannudin; Sopandi, W.; Sujana, A.; Sukardi, R.

2018-05-01

The purpose of this study is to determine the ability of pre-service primary school teachers (PSPST) in explaining the phenomenon of water and air pollution scientifically. The research method used descriptive method of analysis with qualitative approach. The respondents were PSPTP at 4th semester. This study used a four-tier instrument diagnostic test. The number of subjects was 84 PSPTP at Universitas Pendidikan Indonesia, Kampus Daerah Sumedang. The results demonstrate the ability of PSPST in explaining water and air pollution scientifically. The results show that only 6% of PSPST who are able to explain the phenomenon of water pollution and only 4% of PSPST who are able to explain the phenomenon of air pollution. The fact should be attention for PSPST because these understanding are crucial in the process of learning activities in the classroom.

Why Compositional Convection Cannot Explain Substellar Objects’ Sharp Spectral-type Transitions

Science.gov (United States)

Leconte, Jérémy

2018-02-01

As brown dwarfs and young giant planets cool down, they are known to experience various chemical transitions—for example, from {CO} rich L-dwarfs to methane rich T-dwarfs. Those chemical transitions are accompanied by spectral transitions with sharpness that cannot be explained by chemistry alone. In a series of articles, Tremblin et al. proposed that some of the yet-unexplained features associated with these transitions could be explained by a reduction of the thermal gradient near the photosphere. To explain, in turn, this more isothermal profile, they invoke the presence of an instability analogous to fingering convection—compositional convection—triggered by the change in mean molecular weight of the gas due to the chemical transitions mentioned above. In this Letter, we use existing arguments to demonstrate that any turbulent transport, if present, would in fact increase the thermal gradient. This misinterpretation comes from the fact that turbulence mixes/homogenizes entropy (potential temperature) instead of temperature. So, while increasing transport, turbulence in an initially stratified atmosphere actually carries energy downward, whether it is due to fingering or any other type of compositional convection. These processes therefore cannot explain the features observed along the aforementioned transitions by reducing the thermal gradient in the atmosphere of substellar objects. Understanding the microphysical and dynamical properties of clouds at these transitions thus probably remains our best way forward.

Larval trematodes in freshwater molluscs from the Elbe to Danube rivers (Southeast Germany): before and today

Czech Academy of Sciences Publication Activity Database

Faltýnková, Anna; Haas, W.

2006-01-01

Roč. 99, č. 5 (2006), s. 572-582 ISSN 0932-0113 R&D Projects: GA AV ČR IAA6022404; GA ČR GD524/03/H133; GA MŠk LC522 Institutional research plan: CEZ:AV0Z60220518 Keywords : Trematoda * cercariae * Mollusca Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.140, year: 2006

EXPLAINING THE MOTHERHOOD WAGE PENALTY DURING THE EARLY OCCUPATIONAL CAREER

Science.gov (United States)

STAFF, JEREMY; MORTIMER, JEYLAN T.

2011-01-01

Prior research shows that mothers earn lower hourly wages than women without children, and that this maternal wage penalty cannot be fully explained by differences between mothers and other women in work experience and job characteristics. This research examines whether the residual motherhood wage penalty results from differences between mothers and other women in the accumulation of work interruptions and breaks in schooling. Using longitudinal data for 486 women followed from ages 19 to 31 in the Youth Development Study, we find that accumulated months not in the labor force and not enrolled in school explain the residual pay gap between mothers and other women. PMID:22037996

Explaining Tevatron leptons photons missing- T events with ...

Indian Academy of Sciences (India)

Abstract. The CDF experiment reported a lepton photon missing transverse energy. (/ET) signal 3σ in excess of the standard model prediction in Tevatron Run I data. The excess can be explained by the resonant production of a smuon, which subsequently decays to a muon, a photon and a gravitino. Here, we perform ...

A More Practical Method for Explaining Equilibrium

OpenAIRE

Yi-Jang Yu

2014-01-01

The aim of this study is to suggest a more practical method for explaining market equilibrium in a two-dimensional risk-return world. Its main difference from textbook contents is to define, in both qualitative and quantitative ways, the environment or the system factor and treat it as an endogenous variable. Once the two-dimensional framework that is capable of managing uncertainty and environmental relationship can be reasonably established, a greater number of economic issues can be effect...

Explaining seeing? Disentangling qualia from perceptual organization.

Science.gov (United States)

Ibáñez, Agustin; Bekinschtein, Tristan

2010-09-01

Abstract Visual perception and integration seem to play an essential role in our conscious phenomenology. Relatively local neural processing of reentrant nature may explain several visual integration processes (feature binding or figure-ground segregation, object recognition, inference, competition), even without attention or cognitive control. Based on the above statements, should the neural signatures of visual integration (via reentrant process) be non-reportable phenomenological qualia? We argue that qualia are not required to understand this perceptual organization.

How Much of Language Acquisition Does Operant Conditioning Explain?

Science.gov (United States)

Sturdy, Christopher B; Nicoladis, Elena

2017-01-01

Since the 1950s, when Chomsky argued that Skinner's arguments could not explain syntactic acquisition, psychologists have generally avoided explicitly invoking operant or instrumental conditioning as a learning mechanism for language among human children. In this article, we argue that this is a mistake. We focus on research that has been done on language learning in human infants and toddlers in order to illustrate our points. Researchers have ended up inventing learning mechanisms that, in actual practice, not only resemble but also in fact are examples of operant conditioning (OC) by any other name they select. We argue that language acquisition researchers should proceed by first ruling out OC before invoking alternative learning mechanisms. While it is possible that OC cannot explain all of the language acquisition, simple learning mechanisms that work across species may have some explanatory power in children's language learning.

Asset pricing puzzles explained by incomplete Brownian equilibria

DEFF Research Database (Denmark)

Christensen, Peter Ove; Larsen, Kasper

We examine a class of Brownian based models which produce tractable incomplete equilibria. The models are based on finitely many investors with heterogeneous exponential utilities over intermediate consumption who receive partially unspanned income. The investors can trade continuously on a finit...... markets. Consequently, our model can simultaneously help explaining the risk-free rate and equity premium puzzles....

Weaker dental enamel explains dental decay.

Science.gov (United States)

Vieira, Alexandre R; Gibson, Carolyn W; Deeley, Kathleen; Xue, Hui; Li, Yong

2015-01-01

Dental caries continues to be the most prevalent bacteria-mediated non-contagious disease of humankind. Dental professionals assert the disease can be explained by poor oral hygiene and a diet rich in sugars but this does not account for caries free individuals exposed to the same risk factors. In order to test the hypothesis that amount of amelogenin during enamel development can influence caries susceptibility, we generated multiple strains of mice with varying levels of available amelogenin during dental development. Mechanical tests showed that dental enamel developed with less amelogenin is "weaker" while the dental enamel of animals over-expressing amelogenin appears to be more resistant to acid dissolution.

SOME THEORETICAL MODELS EXPLAINING ADVERTISING EFFECTS

Directory of Open Access Journals (Sweden)

Vasilica Magdalena SOMEŞFĂLEAN

2014-06-01

Full Text Available Persuade clients is still the main focus of the companies, using a set of methods and techniques designed to influence their behavior, in order to obtain better results (profits over a longer period of time. Since the late nineteenth - early twentieth century, the american E.St.Elmo Lewis, considered a pioneer in advertising and sales, developed the first theory, AIDA model, later used by marketers and advertisers to develop a marketing communications strategy. Later studies have developed other models that are the main subject of this research, which explains how and why persuasive communication works, to understand why some approaches are effective and others are not.

Explaining socio-demographic differences in disengagement from sports in adolescence.

Science.gov (United States)

Prins, Richard G; Kamphuis, Carlijn B M; van Empelen, Pepijn; Beenackers, Mariëlle A; Brug, Johannes; Mackenbach, Johan P; Oenema, Anke

2013-10-01

The purpose of this longitudinal study is to identify risk groups for disengagement from sports during adolescence. In addition, it will be explored whether cognitive and environmental factors can explain socio-demographic differences in disengagement from sports. Data were obtained from the Environmental Determinants of Obesity in Rotterdam Schoolchildren study, and 357 adolescents were eligible for analysis. Socio-demographics (gender, ethnicity, education), individual cognitions and neighbourhood perceptions were assessed at baseline (2005/2006), and sports participation at baseline and at follow-up (2007/2008). Two dichotomous outcome variables were constructed: (i) disengagement from sports (yes/no) and (ii) ceased compliance with the fitnorm (i.e. cease engaging in sports ≥3 times/wk) (yes/no). In logistic regression and mediation analyses, we identified socio-demographic differences in the two outcomes. Subsequently, we applied mediation analyses to identify the contribution of cognitive and environmental explanatory factors of the socio-demographic differences. Girls [odds ratio (OR): 2.5, 95% confidence interval (CI): 1.5-4.5] were more likely than boys to disengage from sports. Girls (OR: 2.5, 95% CI: 1.4-4.2), adolescents of non-Western background (OR: 1.8, 95% CI: 1.0-3.0) and those in lower educational levels (OR: 1.7, 95% CI: 1.0-2.9) were more likely to cease compliance with the fitnorm. Perceived neighbourhood safety partly explained gender differences in disengagement from sports (8%). Intention partly explained ethnical (32%) and educational differences (37%) in ceasing compliance with the fitnorm. Girls, lower-educated adolescents and those with a non-Western background showed more pronounced reductions in sports participation and compliance with the fitnorm. Intention and perceived neighbourhood safety could partially explain these differences.

Explaining mastitis incidence in Dutch dairy farming: the influence of farmers' attitudes and behaviour.

Science.gov (United States)

Jansen, J; van den Borne, B H P; Renes, R J; van Schaik, G; Lam, T J G M; Leeuwis, C

2009-11-15

When mastitis incidence increases, either infection pressure has increased or cows' resistance has decreased. This usually indicates that farm management is not optimal. Numerous quantitative studies have demonstrated the effect of management practices on mastitis. In most of these studies, the identified risk factors could explain only part of the variance in mastitis incidence on farms. Several studies suggest that the unexplained variance is caused by farmers' attitudes towards different aspects of mastitis treatment and preventive behaviour. This study aims to determine, to quantify and to specify the extent to which farmers' attitudes, over and above farmers' behaviour, are factors that explain the variation in mastitis incidence, measured in terms of the quantifiable effect of management factors. An extensive survey on self-reported attitudes, behaviour and mastitis incidence was conducted on 336 Dutch dairy farms. Results of multiple linear regression analyses show that farmers' self-reported behaviour and attitudes together explain 48%, 31% and 23% of the variation within, respectively, the average farm bulk milk somatic cell count (BMSCC), the clinical mastitis incidence and the combined clinical and subclinical mastitis incidence. Both behaviour and attitudes explain part of the variance. However, most of the variance in all three dependant measures is explained solely by the attitude variables. The variation in BMSCC value is best explained by (1) farmers' normative frame of reference about mastitis, (2) farmers' perceptions about the control of mastitis and (3) the perceived effect of a BMSCC penalty level. The variation in clinical mastitis is best explained by farmers' perceptions about mastitis control. The variation in the combined clinical and subclinical mastitis incidence rate is best explained by the perceived effect of a BMSCC penalty level and the frequency of contact with others. The results of this study show that farmers' attitudes are a

Explaining the Pattern of CSDP-Operations: Towards a Theoretical Synthesis

Directory of Open Access Journals (Sweden)

Tim Haesebrouck

2015-06-01

Full Text Available The EU’s Common Security and Defence Policy (CSDP has mainly been used to deploy small-scale operations, which generally did not provide the member states with clear security benefits. This article combines insights from different theories of international relations to explain this disappointing track record. It argues that liberal theories adequately identify the domestic pressures the member states’ governments need to accommodate in the area of crisis management. Constructivism, on its part, properly emphasises the diverging strategic cultures of the member states. Both theories however fail to explain why domestic pressures and diverging strategic cultures lead to small-scale operations. Rational-choice institutionalism does provide a convincing explanation for the latter by drawing attention to the CSDP’s ineffective institutional design. Realism, in turn, is best positioned to explain why the CSDP was not designed more effectively, by emphasising the reluctance of states to transfer sovereignty to international organisations. The article concludes by discussing two measures that could alleviate the impact of the identified impediments on the CSDP’s track record: devising a CSDP-strategy and adapting the consensus rule. However, since the latter is very unlikely in the near future, the CSDP is not expected to develop into a more effective framework for crisis management.

Explaining ecological clusters of maternal depression in South Western Sydney

Science.gov (United States)

2014-01-01

Background The aim of the qualitative study reported here was to: 1) explain the observed clustering of postnatal depressive symptoms in South Western Sydney; and 2) identify group-level mechanisms that would add to our understanding of the social determinants of maternal depression. Methods Critical realism provided the methodological underpinning for the study. The setting was four local government areas in South Western Sydney, Australia. Child and Family practitioners and mothers in naturally occurring mothers groups were interviewed. Results Using an open coding approach to maximise emergence of patterns and relationships we have identified seven theoretical concepts that might explain the observed spatial clustering of maternal depression. The theoretical concepts identified were: Community-level social networks; Social Capital and Social Cohesion; "Depressed community"; Access to services at the group level; Ethnic segregation and diversity; Supportive social policy; and Big business. Conclusions We postulate that these regional structural, economic, social and cultural mechanisms partially explain the pattern of maternal depression observed in families and communities within South Western Sydney. We further observe that powerful global economic and political forces are having an impact on the local situation. The challenge for policy and practice is to support mothers and their families within this adverse regional and global-economic context. PMID:24460690

Genetic pleiotropy explains associations between musical auditory discrimination and intelligence.

Science.gov (United States)

Mosing, Miriam A; Pedersen, Nancy L; Madison, Guy; Ullén, Fredrik

2014-01-01

Musical aptitude is commonly measured using tasks that involve discrimination of different types of musical auditory stimuli. Performance on such different discrimination tasks correlates positively with each other and with intelligence. However, no study to date has explored these associations using a genetically informative sample to estimate underlying genetic and environmental influences. In the present study, a large sample of Swedish twins (N = 10,500) was used to investigate the genetic architecture of the associations between intelligence and performance on three musical auditory discrimination tasks (rhythm, melody and pitch). Phenotypic correlations between the tasks ranged between 0.23 and 0.42 (Pearson r values). Genetic modelling showed that the covariation between the variables could be explained by shared genetic influences. Neither shared, nor non-shared environment had a significant effect on the associations. Good fit was obtained with a two-factor model where one underlying shared genetic factor explained all the covariation between the musical discrimination tasks and IQ, and a second genetic factor explained variance exclusively shared among the discrimination tasks. The results suggest that positive correlations among musical aptitudes result from both genes with broad effects on cognition, and genes with potentially more specific influences on auditory functions.

What Explains Patterns of Diversification and Richness among Animal Phyla?

Science.gov (United States)

Jezkova, Tereza; Wiens, John J

2017-03-01

Animal phyla vary dramatically in species richness (from one species to >1.2 million), but the causes of this variation remain largely unknown. Animals have also evolved striking variation in morphology and ecology, including sessile marine taxa lacking heads, eyes, limbs, and complex organs (e.g., sponges), parasitic worms (e.g., nematodes, platyhelminths), and taxa with eyes, skeletons, limbs, and complex organs that dominate terrestrial ecosystems (arthropods, chordates). Relating this remarkable variation in traits to the diversification and richness of animal phyla is a fundamental yet unresolved problem in biology. Here, we test the impacts of 18 traits (including morphology, ecology, reproduction, and development) on diversification and richness of extant animal phyla. Using phylogenetic multiple regression, the best-fitting model includes five traits that explain ∼74% of the variation in diversification rates (dioecy, parasitism, eyes/photoreceptors, a skeleton, nonmarine habitat). However, a model including just three (skeleton, parasitism, habitat) explains nearly as much variation (∼67%). Diversification rates then largely explain richness patterns. Our results also identify many striking traits that have surprisingly little impact on diversification (e.g., head, limbs, and complex circulatory and digestive systems). Overall, our results reveal the key factors that shape large-scale patterns of diversification and richness across >80% of all extant, described species.

Explaining ecological clusters of maternal depression in South Western Sydney.

Science.gov (United States)

Eastwood ED, John; Kemp, Lynn; Jalaludin, Bin

2014-01-24

The aim of the qualitative study reported here was to: 1) explain the observed clustering of postnatal depressive symptoms in South Western Sydney; and 2) identify group-level mechanisms that would add to our understanding of the social determinants of maternal depression. Critical realism provided the methodological underpinning for the study. The setting was four local government areas in South Western Sydney, Australia. Child and Family practitioners and mothers in naturally occurring mothers groups were interviewed. Using an open coding approach to maximise emergence of patterns and relationships we have identified seven theoretical concepts that might explain the observed spatial clustering of maternal depression. The theoretical concepts identified were: Community-level social networks; Social Capital and Social Cohesion; "Depressed community"; Access to services at the group level; Ethnic segregation and diversity; Supportive social policy; and Big business. We postulate that these regional structural, economic, social and cultural mechanisms partially explain the pattern of maternal depression observed in families and communities within South Western Sydney. We further observe that powerful global economic and political forces are having an impact on the local situation. The challenge for policy and practice is to support mothers and their families within this adverse regional and global-economic context.

Psychological flexibility and mindfulness explain intuitive eating in overweight adults.

Science.gov (United States)

Sairanen, Essi; Tolvanen, Asko; Karhunen, Leila; Kolehmainen, Marjukka; Järvelä, Elina; Rantala, Sanni; Peuhkuri, Katri; Korpela, Riitta; Lappalainen, Raimo

2015-07-01

The current study investigated whether mindfulness and psychological flexibility, independently and together, explain intuitive eating. The participants were overweight or obese persons (N = 306) reporting symptoms of perceived stress and enrolled in a psychological lifestyle intervention study. Participants completed self-report measures of psychological flexibility; mindfulness including the subscales observe, describe, act with awareness, non-react, and non-judgment; and intuitive eating including the subscales unconditional permission to eat, eating for physical reasons, and reliance on hunger/satiety cues. Psychological flexibility and mindfulness were positively associated with intuitive eating factors. The results suggest that mindfulness and psychological flexibility are related constructs that not only account for some of the same variance in intuitive eating, but they also account for significant unique variances in intuitive eating. The present results indicate that non-judgment can explain the relationship between general psychological flexibility and unconditional permission to eat as well as eating for physical reasons. However, mindfulness skills-acting with awareness, observing, and non-reacting-explained reliance on hunger/satiety cues independently from general psychological flexibility. These findings suggest that mindfulness and psychological flexibility are interrelated but not redundant constructs and that both may be important for understanding regulation processes underlying eating behavior. © The Author(s) 2015.

Do plant traits explain tree seedling survival in bogs?

NARCIS (Netherlands)

Limpens, J.; Egmond, van E.; Li, B.; Holmgren, M.

2013-01-01

Moss-dominated peat bogs store approximately 30% of global soil carbon. A climate induced shift from current moss-dominated conditions to tree-dominated states is expected to strongly affect their functioning and carbon sequestration capacity. Consequently, unraveling the mechanisms that may explain

Do occupational demands explain the educational gradient in health?

NARCIS (Netherlands)

Meyer, S.C.; Künn-Nelen, A.C.

2014-01-01

The aim of this paper is to investigate to what extent occupation-specific demands explain the relationship between education and health. We concentrate on ergonomic, environmental, psychical, social and time demands. Merging the German Microcensus 2009 data with a dataset including detailed

How Much of Language Acquisition Does Operant Conditioning Explain?

Science.gov (United States)

Sturdy, Christopher B.; Nicoladis, Elena

2017-01-01

Since the 1950s, when Chomsky argued that Skinner’s arguments could not explain syntactic acquisition, psychologists have generally avoided explicitly invoking operant or instrumental conditioning as a learning mechanism for language among human children. In this article, we argue that this is a mistake. We focus on research that has been done on language learning in human infants and toddlers in order to illustrate our points. Researchers have ended up inventing learning mechanisms that, in actual practice, not only resemble but also in fact are examples of operant conditioning (OC) by any other name they select. We argue that language acquisition researchers should proceed by first ruling out OC before invoking alternative learning mechanisms. While it is possible that OC cannot explain all of the language acquisition, simple learning mechanisms that work across species may have some explanatory power in children’s language learning. PMID:29163295

How Much of Language Acquisition Does Operant Conditioning Explain?

Directory of Open Access Journals (Sweden)

Christopher B. Sturdy

2017-10-01

Full Text Available Since the 1950s, when Chomsky argued that Skinner’s arguments could not explain syntactic acquisition, psychologists have generally avoided explicitly invoking operant or instrumental conditioning as a learning mechanism for language among human children. In this article, we argue that this is a mistake. We focus on research that has been done on language learning in human infants and toddlers in order to illustrate our points. Researchers have ended up inventing learning mechanisms that, in actual practice, not only resemble but also in fact are examples of operant conditioning (OC by any other name they select. We argue that language acquisition researchers should proceed by first ruling out OC before invoking alternative learning mechanisms. While it is possible that OC cannot explain all of the language acquisition, simple learning mechanisms that work across species may have some explanatory power in children’s language learning.

Main features of narrow sociological theories explaining mental disorders

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Opalić Petar

2006-01-01

Full Text Available In the introduction, the author states that sociological theories explaining mental disorders in the narrow sense have originated as an opposition to medical, i.e. biological model of interpreting mental disorders. With regard to this, the following sociological theories explaining mental disorders are presented in more detail: theory of anomie by Durkheim and Merton (with Merton’s typology of deviant behavior, social roles theory by Parsons, labeling theory by Scheff and other authors, theoretical career model of the mentally ill, the concept of psychic disorder of etnomethodology and finally, the anti-psychiatric interpretation of mental disorders. It is concluded that, although historically older, sociological theories of the onset of mental disorders are filling the epistemological void that occurred in understanding the role of society on the whole and a series of social factors particularly on the different aspects of understanding mental disorders.

Explaining residential moving intentions : the case of highway locations

NARCIS (Netherlands)

Hamersma, Marije; Heinen, Eva; Tillema, Taede; Arts, Jos

2013-01-01

In this paper Structural Equation Modeling is used to test a theoretical framework to explain the impact of highway externalities (i.e. accessibility and nuisance) on moving intentions of people living close to highways. We aimed to study whether highway externalities (alongside other contextual

Does Interest rate Exposure explain the Low-Volatility Anomaly?

NARCIS (Netherlands)

Driessen, Joost; Kuiper, Ivo; Beilo, R.

We show that part of the outperformance of low-volatility stocks can be explained by a premium for interest rate exposure. Low-volatility stock portfolios have negative exposure to interest rates, whereas the more volatile stocks have positive exposure. Incorporating an interest rate premium

Does geography or ecology best explain 'cultural' variation among chimpanzee communities?

Science.gov (United States)

Kamilar, Jason M; Marshack, Joshua L

2012-02-01

Much attention has been paid to geographic variation in chimpanzee behavior, but few studies have applied quantitative techniques to explain this variation. Here, we apply methods typically utilized in macroecology to explain variation in the putative cultural traits of chimpanzees. We analyzed published data containing 39 behavioral traits from nine chimpanzee communities. We used a canonical correspondence analysis to examine the relative importance of environmental characteristics and geography, which may be a proxy for inter-community gene flow and/or social transmission, for explaining geographic variation in chimpanzee behavior. We found that geography, and longitude in particular, was the best predictor of behavioral variation. Chimpanzee communities in close longitudinal proximity to each other exhibit similar behavioral repertoires, independent of local ecological factors. No ecological variables were significantly related to behavioral variation. These results support the idea that inter-community dispersal patterns have played a major role in structuring behavioral variation. We cannot be certain whether behavioral variation has a genetic basis, is the result of innovation and diffusion, or a combination of the two. Copyright © 2011 Elsevier Ltd. All rights reserved.

Canonical Cortical Circuit Model Explains Rivalry, Intermittent Rivalry, and Rivalry Memory.

Directory of Open Access Journals (Sweden)

Shashaank Vattikuti

2016-05-01

Full Text Available It has been shown that the same canonical cortical circuit model with mutual inhibition and a fatigue process can explain perceptual rivalry and other neurophysiological responses to a range of static stimuli. However, it has been proposed that this model cannot explain responses to dynamic inputs such as found in intermittent rivalry and rivalry memory, where maintenance of a percept when the stimulus is absent is required. This challenges the universality of the basic canonical cortical circuit. Here, we show that by including an overlooked realistic small nonspecific background neural activity, the same basic model can reproduce intermittent rivalry and rivalry memory without compromising static rivalry and other cortical phenomena. The background activity induces a mutual-inhibition mechanism for short-term memory, which is robust to noise and where fine-tuning of recurrent excitation or inclusion of sub-threshold currents or synaptic facilitation is unnecessary. We prove existence conditions for the mechanism and show that it can explain experimental results from the quartet apparent motion illusion, which is a prototypical intermittent rivalry stimulus.

Explaining resource consumption among non-normal neonates

Science.gov (United States)

Schwartz, Rachel M.; Michelman, Thomas; Pezzullo, John; Phibbs, Ciaran S.

1991-01-01

The adoption by Medicare in 1983 of prospective payment using diagnosis-related groups (DRGs) has stimulated research to develop case-mix grouping schemes that more accurately predict resource consumption by patients. In this article, the authors explore a new method designed to improve case-mix classification for newborns through the use of birth weight in combination with DRGs to adjust the unexplained case-mix severity. Although the findings are developmental in nature, they reveal that the model significantly improves our ability to explain resource use. PMID:10122360

Explaining variation in Down's syndrome screening uptake

DEFF Research Database (Denmark)

Crombag, Neeltje M T H; Vellinga, Ynke E; Kluijfhout, Sandra A

2014-01-01

), in an attempt to explain the observed variation in national uptake rates. METHODS: We used a mixed methods approach with an embedded design: a) documentary analysis and b) expert stakeholder analysis. National central statistical offices and legal documents were studied first to gain insight in demographic....... RESULTS: There were many similarities in the demographics, healthcare systems, government abortion legislation and Down's syndrome screening policy across the studied countries. However, the additional cost for Down's syndrome screening over and above standard antenatal care in the Netherlands...

Microhabitat and Climatic Niche Change Explain Patterns of Diversification among Frog Families.

Science.gov (United States)

Moen, Daniel S; Wiens, John J

2017-07-01

A major goal of ecology and evolutionary biology is to explain patterns of species richness among clades. Differences in rates of net diversification (speciation minus extinction over time) may often explain these patterns, but the factors that drive variation in diversification rates remain uncertain. Three important candidates are climatic niche position (e.g., whether clades are primarily temperate or tropical), rates of climatic niche change among species within clades, and microhabitat (e.g., aquatic, terrestrial, arboreal). The first two factors have been tested separately in several studies, but the relative importance of all three is largely unknown. Here we explore the correlates of diversification among families of frogs, which collectively represent ∼88% of amphibian species. We assemble and analyze data on phylogeny, climate, and microhabitat for thousands of species. We find that the best-fitting phylogenetic multiple regression model includes all three types of variables: microhabitat, rates of climatic niche change, and climatic niche position. This model explains 67% of the variation in diversification rates among frog families, with arboreal microhabitat explaining ∼31%, niche rates ∼25%, and climatic niche position ∼11%. Surprisingly, we show that microhabitat can have a much stronger influence on diversification than climatic niche position or rates of climatic niche change.

The boundaries of instance-based learning theory for explaining decisions from experience.

Science.gov (United States)

Gonzalez, Cleotilde

2013-01-01

Most demonstrations of how people make decisions in risky situations rely on decisions from description, where outcomes and their probabilities are explicitly stated. But recently, more attention has been given to decisions from experience where people discover these outcomes and probabilities through exploration. More importantly, risky behavior depends on how decisions are made (from description or experience), and although prospect theory explains decisions from description, a comprehensive model of decisions from experience is yet to be found. Instance-based learning theory (IBLT) explains how decisions are made from experience through interactions with dynamic environments (Gonzalez et al., 2003). The theory has shown robust explanations of behavior across multiple tasks and contexts, but it is becoming unclear what the theory is able to explain and what it does not. The goal of this chapter is to start addressing this problem. I will introduce IBLT and a recent cognitive model based on this theory: the IBL model of repeated binary choice; then I will discuss the phenomena that the IBL model explains and those that the model does not. The argument is for the theory's robustness but also for clarity in terms of concrete effects that the theory can or cannot account for. Copyright © 2013 Elsevier B.V. All rights reserved.

Explaining Cross-Country Differences in Attitudes Towards Immigration in the EU-15

DEFF Research Database (Denmark)

Malchow-Møller, Nikolaj; Munch, Jakob Roland; Schroll, Sanne

2009-01-01

In this paper, we use data from the first two rounds of the European Social Survey to analyze the extent to which differences in average attitudes towards immigration across the EU-15 countries may be explained by differences in socioeconomic characteristics and individually perceived consequences...... of immigration, using an extension of a decomposition technique developed by Fairlie (2005). We find that despite the significant effects of socioeconomic characteristics on attitudes, differences in the distributions of these characteristics can only explain a modest share of the cross-country variation...... in average attitudes. A larger part can be explained by differences in perceived consequences of immigration, but the main part is still left unexplained. Apart from providing useful input for policy makers working in the area of immigration policy, this raises a number of questions for further research...

Explaining Cross-Country Differences in Attitudes towards Immigration in the EU-15

DEFF Research Database (Denmark)

Malchow-Møller, Nikolaj; Munch, Jakob Roland; Schroll, Sanne

2007-01-01

In this paper, we use data from the first two rounds of the European Social Survey to analyze the extent to which differences in average attitudes towards immigration across the EU-15 countries may be explained by differences in socioeconomic characteristics and individually perceived consequences...... of immigration, using an extension of a decomposition technique developed by Fairlie (2005). We find that despite the significant effects of socioeconomic characteristics on attitudes, differences in the distributions of these characteristics can only explain a modest share of the cross-country variation...... in average attitudes. A larger part can be explained by differences in perceived consequences of immigration, but the main part is still left unexplained. Apart from providing useful input for policy makers working in the area of immigration policy, this raises a number of questions for further research...

Explaining Cross-Country Differences in Attitudes Towards Immigration in the EU-15

DEFF Research Database (Denmark)

Malchow-Møller, Nikolaj; Munch, Jakob Roland; Skaksen, Jan Rose

In this paper, we use data from the first two rounds of the European Social Survey to analyse the extent to which differences in average attitudes towards immigration across the EU-15 countries may be explained by differences in socioeconomic characteristics and individually perceived consequences...... of immigration, using an extension of a decomposition technique developed by Fairlie (2005). We find that despite the significant effects of socioeconomic characteristics on attitudes, differences in the distributions of these characteristics can only explain a modest share of the cross-country variation...... in average attitudes. A larger part can be explained by differences in perceived consequences of immigration, but the main part is still left unexplained. Apart from providing useful input for policy makers working in the area of immigration policy, this raises a number of questions for further research...

Imitation explains the propagation, not the stability of animal culture.

Science.gov (United States)

Claidière, Nicolas; Sperber, Dan

2010-02-22

For acquired behaviour to count as cultural, two conditions must be met: it must propagate in a social group, and it must remain stable across generations in the process of propagation. It is commonly assumed that imitation is the mechanism that explains both the spread of animal culture and its stability. We review the literature on transmission chain studies in chimpanzees (Pan troglodytes) and other animals, and we use a formal model to argue that imitation, which may well play a major role in the propagation of animal culture, cannot be considered faithful enough to explain its stability. We consider the contribution that other psychological and ecological factors might make to the stability of animal culture observed in the wild.

Explaining e-business adoption - Innovation & entrepreneurship in Dutch SMEs

NARCIS (Netherlands)

van der Veen, M.

2005-01-01

Explaining e-business adoptionThis dissertation deals with the explanation of e-business adoption in Dutch small and medium sized enterprises. The adoption of e-business plays an important part in making existing business more efficient and effective. Moreover, it is a tool for business development

Explaining dehumanization among children: the interspecies model of prejudice.

Science.gov (United States)

Costello, Kimberly; Hodson, Gordon

2014-03-01

Although many theoretical approaches have emerged to explain prejudices expressed by children, none incorporate outgroup dehumanization, a key predictor of prejudice among adults. According to the Interspecies Model of Prejudice, beliefs in the human-animal divide facilitate outgroup prejudice through fostering animalistic dehumanization (Costello & Hodson, 2010). In the present investigation, White children attributed Black children fewer 'uniquely human' characteristics, representing the first systematic evidence of racial dehumanization among children (Studies 1 and 2). In Study 2, path analyses supported the Interspecies Model of Prejudice: children's human-animal divide beliefs predicted greater racial prejudice, an effect explained by heightened racial dehumanization. Similar patterns emerged among parents. Furthermore, parent Social Dominance Orientation predicted child prejudice indirectly through children's endorsement of a hierarchical human-animal divide and subsequent dehumanizing tendencies. Encouragingly, children's human-animal divide perceptions were malleable to an experimental prime highlighting animal-human similarity. Implications for prejudice interventions are considered. © 2012 The British Psychological Society.

Explaining judicial corruption in the courts of Chile, Peru and Ecuador

Directory of Open Access Journals (Sweden)

Santiago Basabe-Serrano

2013-07-01

Full Text Available This article identifies the main variables that explain judicial corruption in Chile, Peru, and Ecuador. Improving the current methodological strategies used to measure judicial corruption and incorporating endogenous and exogenous variables in the model, this article argues that legal training of the judges, respect for the judicial career, and the fragmentation of political power explain different degrees of judicial corruption. Through a comparative diachronic and synchronic research design of Chile, Peru and Ecuador, the article shows institutional designs with more legal steps will be more inclined to illegal payments or other types of judicial corruption.

Explaining R{sub D}{sup {sub (}{sub *}{sub )}} with leptoquarks and flavor symmetries

Energy Technology Data Exchange (ETDEWEB)

Schoenwald, Kay [TU Dortmund (Germany)

2016-07-01

Recently LHCb confirmed the anomalies in R{sub D}{sup {sub (}{sub *}{sub )}} previously measured by BaBar and Belle. We use flavor symmetries capable of explaining the observed mixing in the quark and lepton sector to constrain leptoquark couplings and study whether this models can explain the anomalies in R{sub D}{sup {sub (}{sub *}{sub )}}.

Cuantificación de metales pesados en Anadara tuberculosa(Mollusca:bivalvia del estero Huaylá de Puerto Bolívar, por espectrofotometría de absorción atómica

Directory of Open Access Journals (Sweden)

Collaguazo-Collaguazo, Yadira

2017-09-01

Full Text Available The presence of heavy metals in bivalve molluscs implies a serious problem for the consumers health of this type of food. Therefore, the objective of the present investigation was to determine the presence of heavy metals in Anadara tuberculosa, mollusc of commercial importance at Puerto Bolívar, Ecuador. Atomic absorption spectrophotometry was the method used to quantify the concentration of heavy metals. The concentration of six metals was determined: lead (Pb, arsenic (As, mercury (Hg, cadmium (Cd, chromium (Cr and cobalt (Co. The average values obtained, expressed in mg.kg-1 were: Pb (7.52 ± 0.46; As (1.55 ± 0.14; Hg (364.38 ± 91.39; Cd (1.68 ± 0.28; Cr (3,89 ± 1,82 and Co (2,71 ± 0,34 in A. tuberculosa The results show that Pb, As, Cd, and Hg exceed the maximum permissible limits, mercury exceeds by more than 100 times the limit value. The smaller size (3-4 cm studied mollusc, has the capacity to bioaccumulate higher concentration of Pb, Cd and Cr.

Explaining differences between hospitals in number of organ donors.

NARCIS (Netherlands)

Friele, R.D.; Coppen, R.; Marquet, R.L.; Gevers, J.K.M.

2006-01-01

The shortage of donor organs calls for a careful examination of all improvement options. In this study, 80 Dutch hospitals were compared. They provided 868 donors in a 5-year period, constituting 91% of all donors in that period in The Netherlands. Multilevel regression analysis was used to explain

Which Mechanisms Explain Monetary Returns to International Student Mobility?

Science.gov (United States)

Kratz, Fabian; Netz, Nicolai

2018-01-01

The authors develop a conceptual framework explaining monetary returns to international student mobility (ISM). Based on data from two German graduate panel surveys, they test this framework using growth curve models and Oaxaca-Blinder decompositions. The results indicate that ISM-experienced graduates enjoy a steeper wage growth after graduation…

Can selection explain the protective effects of farming on asthma?

Directory of Open Access Journals (Sweden)

Wijnand Eduard

2015-09-01

No healthy worker selection into farming was observed and changes in asthma prevalence due to early retirement were small. Selection effects are therefore unlikely to explain the protective effects of farming on asthma.

Explaining variation in the uptake of HPV vaccination in England

Directory of Open Access Journals (Sweden)

Whynes David K

2011-03-01

Full Text Available Abstract Background In England, two national programmes of HPV vaccination for girls have been instituted, a routine programme for 12- and 13-year-olds and a catch-up programme for 17- and 18-year-olds. Uptake rates across the country have been far from uniform, and this research sought to identify factors explaining the variation in uptake by locality. Methods An association between uptake, deprivation and ethnic background had been established in pilot research. The present analysis was conducted at an aggregate, Primary Care Trust (PCT, level for the first year of the programmes. Published measures of HPV vaccination uptake, material deprivation, ethnic composition of PCT populations, primary care quality, and uptake of cervical screening and of other childhood immunisations were collated. Strong evidence of collinearity amongst the explanatory variables required a factor analysis to be undertaken. This provided four independent factors, used thereafter in regression models to explain uptake by PCT. Results The factor analysis revealed that ethnic composition was associated with attitudes towards cervical screening and other childhood vaccinations, whilst material deprivation and quality of primary care were orthogonal. Ethnic composition, early childhood vaccination, cervical screening and primary care quality were found to be influential in predicting uptake in both the routine and the catch-up cohorts, although with a lower degree of confidence in the case of the last two independent variables. Lower primary care quality was significant in explaining a greater fall in vaccination uptake between the first two doses in the catch-up cohort. Greater deprivation was a significant explanatory factor for both uptake and the fall in uptake between doses for the catch-up cohort but not for uptake in the routine cohort. Conclusion These results for uptake of the first year of the national programme using aggregate data corroborate findings from

EVE: Explainable Vector Based Embedding Technique Using Wikipedia

OpenAIRE

Qureshi, M. Atif; Greene, Derek

2017-01-01

We present an unsupervised explainable word embedding technique, called EVE, which is built upon the structure of Wikipedia. The proposed model defines the dimensions of a semantic vector representing a word using human-readable labels, thereby it readily interpretable. Specifically, each vector is constructed using the Wikipedia category graph structure together with the Wikipedia article link structure. To test the effectiveness of the proposed word embedding model, we consider its usefulne...

Explaining regional variation in home care use by demand and supply variables.

Science.gov (United States)

van Noort, Olivier; Schotanus, Fredo; van de Klundert, Joris; Telgen, Jan

2018-02-01

In the Netherlands, home care services like district nursing and personal assistance are provided by private service provider organizations and covered by private health insurance companies which bear legal responsibility for purchasing these services. To improve value for money, their procurement increasingly replaces fee-for-service payments with population based budgets. Setting appropriate population budgets requires adaptation to the legitimate needs of the population, whereas historical costs are likely to be influenced by supply factors as well, not all of which are necessarily legitimate. Our purpose is to explain home care costs in terms of demand and supply factors. This allows for adjusting historical cost patterns when setting population based budgets. Using expenses claims of 60 Dutch municipalities, we analyze eight demand variables and five supply variables with a multiple regression model to explain variance in the number of clients per inhabitant, costs per client and costs per inhabitant. Our models explain 69% of variation in the number of clients per inhabitant, 28% of costs per client and 56% of costs per inhabitant using demand factors. Moreover, we find that supply factors explain an additional 17-23% of variation. Predictors of higher utilization are home care organizations that are integrated with intramural nursing homes, higher competition levels among home care organizations and the availability of complementary services. Copyright © 2017. Published by Elsevier B.V.

Thrive or Survive? Explaining Variation in Economic Outcomes for Refugees

Directory of Open Access Journals (Sweden)

Alexander Betts

2017-11-01

Full Text Available In the context of protracted refugee situations, there has been a revival in concern among policymakers to transcend the so-called humanitarian-development divide and create greater opportunities for self-reliance. Yet, these discussions too often neglect an analytical focus on refugees’ own economic lives, and their own interactions with markets.Despite a growing literature on the economic lives of refugees, much of that work has lacked theory or data. The work that has been quantitative has generally focused on the economic impact of refugees on host countries rather than explaining variation in economic outcomes for refugees.  In order to explain variation in economic outcomes for refugees, this paper asks three questions about the economic lives of refugees: 1 what makes the economic lives of refugees distinctive from other populations; 2 what explains variation in refugees’ income levels; and 3 what role does entrepreneurship play in shaping refugees’ economic outcomes?In order to answer these questions, the paper draws upon extensive qualitative and quantitative research conducted in Uganda by the Humanitarian Innovation Project at Oxford University. The quantitative data set is based on a survey of 2,213 refugees in three types of contexts: urban (Kampala, protracted camps (Nakivale and Kyangwali settlements, and emergency camps (Rwamwanja. It supplements this with qualitative research from other parts of Africa and the Middle East. The economic lives of refugees are argued to be distinctive not because refugees are any different qua human beings but because they often occupy a distinctive institutional space. Following new institutional economics, the paper argues that “refugee economies” represent a distinctive analytical space insofar as refugees face different formal and informal institutional barriers and distortions in their economic lives compared to nationals or other migrants. Even within the same country, refugees

Explaining University Students' Effective Use of E-Learning Platforms

Science.gov (United States)

Moreno, Valter; Cavazotte, Flavia; Alves, Isabela

2017-01-01

Students' success in e-learning programs depends on how they adopt and embed technology into their learning activities. Drawing on the Technology Acceptance Model, we propose a framework to explain students' intention to use e-learning platforms effectively, that is, their intention to fully exploit system's functionalities in leaning processes,…

A Conceptual Characterization of Online Videos Explaining Natural Selection

Science.gov (United States)

Bohlin, Gustav; Göransson, Andreas; Höst, Gunnar E.; Tibell, Lena A. E.

2017-01-01

Educational videos on the Internet comprise a vast and highly diverse source of information. Online search engines facilitate access to numerous videos claiming to explain natural selection, but little is known about the degree to which the video content match key evolutionary content identified as important in evolution education research. In…

Dynamics of macrozoobenthos in the Southern Bulgarian Black Sea coastal and open-sea areas

Directory of Open Access Journals (Sweden)

S. STOYKOV

2001-06-01

Full Text Available The paper presents results of analysis of 96 macrozoobenthic samples, collected on a seasonal basis in Bourgas Bay and in open-sea areas offshore Cape Emine (Bulgarian Black Sea in 1996 and 1998. In total 96 taxa were established, distributed in four groups: Polychaeta, Mollusca, Crustacea and “Diversa”. The average density of populations was 1756 ind.m-2 with a predominating abundance of Polychaeta species. The average biomass estimated was 183.02 g.m-2, formed mainly by representatives of Mollusca. The latter species were measured together with the shells, which appraised their individual weights. Seven of the species found had a coefficient of constancy more than 50%. These were the most adapted species to the environmental conditions of the investigated areas. The quantitative and qualitative assessments in this study demonstrate an increasing tendency in the parameters obtained (density, biomass, species diversity in comparison with previous investigations in the early 1990-s, when intensive anthropogenic influence was widely perceived to misbalance the Black Sea ecosystem. The method of Warwick (1986 applied to characterize the water quality of the studied areas allowed us to define them as rather clean or moderately polluted aquatories.

Holography explained in the language of potential scattering

International Nuclear Information System (INIS)

Csonka, P.L.

1978-04-01

Holography is explained in the language of potential scattering kinematics (whereas usually the formalism of wave optics is used). This approach is probably more natural for those who were trained as atomic, nuclear, etc., physicists, but are now attracted by the possibility of x-ray holography. Classical optical instruments are hardly mentioned, and the approximations usually connected with them are not used. Many of the results derived in this report are not new. 5 figures

Can the Theory of Motivation Explain Migration Decisions?

OpenAIRE

Natálie Reichlová

2005-01-01

According to Abraham Maslow's motivational theory, human action is motivated by five groups of human needs. The model introduced in this paper exploits Maslow's theory to explain migration flows between regions. In the model, movement from one place to another influences migrant's utility through three various ways. First, through change in wage caused by different wage levels in each location. Second, through changes in utility connected with individuals safety needs and finally, through dis...

Explaining socioeconomic inequalities in exclusive breast feeding in Norway.

Science.gov (United States)

Bærug, Anne; Laake, Petter; Løland, Beate Fossum; Tylleskär, Thorkild; Tufte, Elisabeth; Fretheim, Atle

2017-08-01

In high-income countries, lower socioeconomic position is associated with lower rates of breast feeding, but it is unclear what factors explain this inequality. Our objective was to examine the association between socioeconomic position and exclusive breast feeding, and to explore whether socioeconomic inequality in exclusive breast feeding could be explained by other sociodemographic characteristics, for example, maternal age and parity, smoking habits, birth characteristics, quality of counselling and breastfeeding difficulties. We used data from a questionnaire sent to mothers when their infants were five completed months as part of a trial of a breastfeeding intervention in Norway. We used maternal education as an indicator of socioeconomic position. Analyses of 1598 mother-infant pairs were conducted using logistic regression to assess explanatory factors of educational inequalities in breast feeding. Socioeconomic inequalities in exclusive breast feeding were present from the beginning and persisted for five completed months, when 22% of the most educated mothers exclusively breast fed compared with 7% of the least educated mothers: OR 3.39 (95% CI 1.74 to 6.61). After adjustment for all potentially explanatory factors, the OR was reduced to 1.49 (95% CI 0.70 to 3.14). This decrease in educational inequality seemed to be mainly driven by sociodemographic factors, smoking habits and breastfeeding difficulties, in particular perceived milk insufficiency. Socioeconomic inequalities in exclusive breast feeding at 5 months were largely explained by sociodemographic factors, but also by modifiable factors, such as smoking habits and breastfeeding difficulties, which can be amenable to public health interventions. NCT01025362. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Understanding Electrochemistry Concepts Using the Predict-Observe-Explain Strategy

Science.gov (United States)

Karamustafaoglu, Sevilay; Mamlok-Naaman, Rachel

2015-01-01

The current study deals with freshman students who study at the Department of Science at the Faculty of Education. The aim of the study was to investigate the effect of teaching electrochemistry concepts using Predict-Observe-Explain (POE) strategy. The study was quasi-experimental design using 20 students each in the experimental group (EG) and…

Can neighborhoods explain racial/ethnic differences in adolescent inactivity?

Science.gov (United States)

Richmond, Tracy K; Field, Alison E; Rich, Michael

2007-01-01

To determine if neighborhoods and their attributes contribute to racial/ethnic disparities in adolescent inactivity. We undertook a cross-sectional analysis of the National Longitudinal Study of Adolescent Health (n = 17,007), a nationally representative school-based study in the United States. Stratifying by gender, we used multivariate linear regression and multi-level modeling to determine whether neighborhood of residence may partially explain racial/ethnic disparities in adolescent physical inactivity, defined as hours viewing television or videos/DVDs and/or playing computer/video games each week. Participants lived in largely segregated communities. Black and Hispanic adolescent girls reported higher levels of inactivity than White adolescent girls (21 vs. 15 vs. 13 hours/week, respectively, p violent crime in the neighborhood was associated with inactivity, despite the individual's perception of his/her neighborhood as safe not being predictive. Although inactivity varies by race/ethnicity and gender, only in Hispanic adolescent girls does neighborhood fully explain the differential use. Our findings suggest that approaches other than changing neighborhood characteristics are needed to eliminate racial/ethnic disparities in adolescent inactivity.

Using Culture to Explain Behavior: An Integrative Cultural Approach

Science.gov (United States)

Shepherd, Hana R.; Stephens, Nicole M.

2010-01-01

While savings rates among low-income families vary greatly, a 2008 National Poverty Center report finds that over 40 percent of low-income families fail to save any money. For decades policy makers and social scientists have sought to explain this phenomenon. Even after accounting for the fact that low-income families have less money to save, why…

Explaining Global Women's Empowerment Using Geographic Inquiry

Science.gov (United States)

Grubbs, Melanie R.

2018-01-01

It is difficult for students who are just being introduced to major geographical concepts to understand how relatively free countries like India or Mali can have such high levels of human rights abuses as child brides, dowry deaths, and domestic violence. Textbooks explain it and video clips show examples, but it still seems surreal to teenagers…

Explaining socio-demographic differences in disengagement from sports in adolescence

NARCIS (Netherlands)

Prins, R.G.; Kamphuis, C.B.M.; van Empelen, P.; Beenackers, M.A.; Brug, J.; Mackenbach, J.P.; Oenema, A.

2013-01-01

Purpose: The purpose of this longitudinal study is to identify risk groups for disengagement from sports during adolescence. In addition, it will be explored whether cognitive and environmental factors can explain socio-demographic differences in disengagement from sports. Methods: Data were

Explaining socio-demographic differences in disengagement from sports in adolescence

NARCIS (Netherlands)

Prins, R.G.; Kamphuis, C.B.M.; Empelen, P. van; Beenackers, M.A.; Brug, J.; Mackenbach, J.P.; Oenema, A.

2013-01-01

Purpose: The purpose of this longitudinal study is to identify risk groups for disengagement from sports during adolescence. In addition, it will be explored whether cognitive and environmental factors can explain socio-demographic differences in disengagement from sports. METHODS: Data were

Explaining Choice and Share of Category Requirements of Biologic Meat

NARCIS (Netherlands)

P.C. Verhoef (Peter); K. Vlagsma-Brangule (Kristine)

2003-01-01

textabstractIn this paper we examine factors determining choice and consumption of biologic or organic meat. In our model explaining choice and share of category requirements, we consider economic/marketing variables (quality, price, and distribution), emotions (fear, empathy, andguilt), social

Explaining gender differences in competitiveness: Gender-task stereotypes

OpenAIRE

Große, Niels Daniel; Riener, Gerhard

2010-01-01

Gender-specific patterns of self-selection into competitive and cooperative environments may have multiple reasons. One of the most prominent explanations to this point is, that there are inherent differences between men and women when it comes to preferences regarding competition. We take a different point of view and claim that gender-task stereotypes are able to explain a large part of the under-representation of women in tournament like environments. We conduct an experiment with a quanti...

Antimicrobial peptides in marine invertebrate health and disease

OpenAIRE

Destoumieux-Garzón, Delphine; Rosa, Rafael Diego; Schmitt, Paulina; Barreto, Cairé; Vidal-Dupiol, Jeremie; Mitta, Guillaume; Gueguen, Yannick; Bachère, Evelyne

2016-01-01

Aquaculture contributes more than one-third of the animal protein from marine sources worldwide. A significant proportion of aquaculture products are derived from marine protostomes that are commonly referred to as ‘marine invertebrates’. Among them, penaeid shrimp (Ecdysozosoa, Arthropoda) and bivalve molluscs (Lophotrochozoa, Mollusca) are economically important. Mass rearing of arthropods and molluscs causes problems with pathogens in aquatic ecosystems that are exploited by humans. Remark...

Stonlach content analyses of Gilchristella aestuarius and Hepsetia ...

African Journals Online (AJOL)

Apseudes digitalis. 80 2,2. 6. 5. Decapoda. Zoea larvae. 6 1,0. 3. 2. Unidentified larvae. 0,3. 2. 0. Insecta. Chironomidae larvae. 810 8,1. 67. 0. 13,5. 65. 13. Terrestrial insects. 2 0,4. 4. 0. Pupae. 22 1,1. 4. 2. Arachnida. Araneida. <0,05. 2. 0. Mollusca. Lamellibranch veligers. 9 <0,05. 8. 0 2240 7,5. 69. 6. Gastropod veligers.

Do executive functions explain the covariance between internalizing and externalizing behaviors?

Science.gov (United States)

Hatoum, Alexander S; Rhee, Soo Hyun; Corley, Robin P; Hewitt, John K; Friedman, Naomi P

2017-11-16

This study examined whether executive functions (EFs) might be common features of internalizing and externalizing behavior problems across development. We examined relations between three EF latent variables (a common EF factor and factors specific to updating working memory and shifting sets), constructed from nine laboratory tasks administered at age 17, to latent growth intercept (capturing stability) and slope (capturing change) factors of teacher- and parent-reported internalizing and externalizing behaviors in 885 individual twins aged 7 to 16 years. We then estimated the proportion of intercept-intercept and slope-slope correlations predicted by EF as well as the association between EFs and a common psychopathology factor (P factor) estimated from all 9 years of internalizing and externalizing measures. Common EF was negatively associated with the intercepts of teacher-rated internalizing and externalizing behavior in males, and explained 32% of their covariance; in the P factor model, common EF was associated with the P factor in males. Shifting-specific was positively associated with the externalizing slope across sex. EFs did not explain covariation between parent-rated behaviors. These results suggest that EFs are associated with stable problem behavior variation, explain small proportions of covariance, and are a risk factor that that may depend on gender.

Discovering and explaining work-family strategies of parents in Luxembourg

NARCIS (Netherlands)

Zhelyazkova, Nevena

2014-01-01

The presented analysis discovers and explains typical patterns of work-family reconciliation for parents who had a child in the same period (2003) and in the same country (Luxembourg), thus facing the same macroeconomic and institutional conditions. Work-family trajectories are reconstructed as

Explaining the R_K and R_{K^*} anomalies

Science.gov (United States)

Ghosh, Diptimoy

2017-10-01

Recent LHCb results on R_{K^*}, the ratio of the branching fractions of B → K^* μ ^+ μ ^- to that of B → K^* e^+ e^-, for the dilepton invariant mass bins q^2 ≡ m_{ℓ ℓ }^2 = [0.045-1.1] GeV^2 and [1.1-6] GeV^2 show approximately 2.5 σ deviations from the corresponding Standard Model prediction in each of the bins. This, when combined with the measurement of R_K (q^2=[1-6] GeV^2), a similar ratio for the decay to a pseudo-scalar meson, highly suggests lepton non-universal new physics in semi-leptonic B meson decays. In this work, we perform a model independent analysis of these potential new physics signals and identify the operators that do the best job in satisfying all these measurements. We show that heavy new physics, giving rise to q^2 independent local 4-Fermi operators of scalar, pseudo-scalar, vector or axial-vector type, is unable to explain all the three measurements simultaneously, in particular R_{K^*} in the bin [0.045-1.1], within their experimental 1σ regions. We point out the possibility to explain R_{K^*} in the low bin by an additional light (≲ 20 {MeV}) vector boson with appropriate coupling strengths to (\\bar{b} s) and (\\bar{e} e).

"Recent" macrofossil remains from the Lomonosov Ridge, central Arctic Ocean

Science.gov (United States)

Le Duc, Cynthia; de Vernal, Anne; Archambault, Philippe; Brice, Camille; Roberge, Philippe

2016-04-01

The examination of surface sediment samples collected from 17 sites along the Lomonosov Ridge at water depths ranging from 737 to 3339 meters during Polarstern Expedition PS87 in 2014 (Stein, 2015), indicates a rich biogenic content almost exclusively dominated by calcareous remains. Amongst biogenic remains, microfossils (planktic and benthic foraminifers, pteropods, ostracods, etc.) dominate but millimetric to centrimetric macrofossils occurred frequently at the surface of the sediment. The macrofossil remains consist of a large variety of taxa, including gastropods, bivalvia, polychaete tubes, scaphopods, echinoderm plates and spines, and fish otoliths. Among the Bivalvia, the most abundant taxa are Portlandia arctica, Hyalopecten frigidus, Cuspidaria glacilis, Policordia densicostata, Bathyarca spp., and Yoldiella spp. Whereas a few specimens are well preserved and apparently pristine, most mollusk shells displayed extensive alteration features. Moreover, most shells were covered by millimeter scale tubes of the serpulid polychaete Spirorbis sp. suggesting transport from low intertidal or subtidal zone. Both the ecological affinity and known geographic distribution of identified bivalvia as named above support the hypothesis of transportation rather than local development. In addition to mollusk shells, more than a hundred fish otoliths were recovered in surface sediments. The otoliths mostly belong to the Gadidae family. Most of them are well preserved and without serpulid tubes attached to their surface, suggesting a local/regional origin, unlike the shell remains. Although recovered at the surface, the macrofaunal assemblages of the Lomonosov Ridge do not necessarily represent the "modern" environments as they may result from reworking and because their occurrence at the surface of the sediment may also be due to winnowing of finer particles. Although the shells were not dated, we suspect that their actual ages may range from modern to several thousands of

Mapping and explaining the use of the left-right divide

Directory of Open Access Journals (Sweden)

André Freire

2013-12-01

Full Text Available This study is about mapping and explaining the use of the Left-Right divide across 14 countries from 5 Continents and relies on the richness of the post electoral mass surveys from the Comparative National Election Project: 14 countries and 18 elections spread over 5 continents. The paper shows not only how extensively the LR divide is used in these 14 countries, but also explains variation across both individuals and countries in terms of the factors determining LR recognition and use. Overall, it is shown that, although seen world-wide, the LR divide (both for self-placement and party placement is more present in long consolidated and middle-aged democracies and countries with freer media systems than in new democracies and societies with less free media systems. In the case of parties LR placement, party size also counts: larger parties are more easily placed. Additionally, we also show that LR recognition is more socially and politically determined in long consolidated and middle-aged democracies and in countries with more freedom of the press than in new democracies and in systems with less free media system. These findings add to the existing knowledge about these topics because previous studies were either country/Continent specific, or, if global in nature, never invested in explaining individual and system variation across 14 from 5 Continents. Besides, these findings mean that in the long term probably the new democracies will converge with the long consolidated or middle-aged ones, but this is an empirical question to be researched in future studies.

Khalid Alshibli explains MGM to Sean O'Keefe

Science.gov (United States)

2002-01-01

Khalid Alshibli of Louisiana State University, project scientist for the Mechanics of Granular Materials (MGM-III) experiment, uses a jar of sand as he explains MGM to NASA Administrator Sean O'Keefe. A training model of an MGM test cell is in the foreground. The activity was part of the Space Research and You education event held by NASA's Office of Biological and Physical Research on June 25, 2002, in Arlington, VA, to highlight the research that will be conducted on STS-107.

Trophic niche overlap between flatfishes in a nursery area on the Portuguese coast

Directory of Open Access Journals (Sweden)

Henrique N. Cabral

2002-09-01

Full Text Available The diets and the trophic niche overlap between seven flatfish species were studied in a coastal nursery adjoining to the Tagus estuary (Portugal. Fish were sampled monthly, from March to November 1999, using a beach seine. Arnoglossus imperialis (Rafinesque, 1810, Arnoglossus laterna (Walbaum, 1792 and Arnoglossus thori Kyle, 1913, fed mainly on crustaceans. The diets of Buglossidium luteum (Risso, 1810 and Dicologoglossa cuneata (Moreau, 1881 were mainly composed of Bivalvia and Polychaeta, while for Scophthalmus rhombus (Linnaeus, 1758 the main food items were Mysidacea and Teleostei. The diet of Pegusa lascaris (Risso, 1810 was mainly composed by Cumacea, Bivalvia, Decapoda and Amphipoda. Based on diet similarities two main groups were identified: one composed of A. imperialis, A. laterna, A. thori and S. rhombus, and the other grouping B. luteum, P. lascaris and D. cuneata. For the most common flatfishes, a similar pattern of diet seasonal variation was found, such that Amphipoda presented higher indices values in the period from March to June, while from July to November, Decapoda were more abundant. Although high values of diet overlap were obtained among some of the species, the main items in the diet of flatfishes are probably the most abundant prey in this coastal area, which suggests a generalist and opportunistic utilization of these food resources. Furthermore, niche overlap between these species is probably minimized by differences in resource use in other niche dimensions, namely time and space.

Mediating Factors Explaining the Association Between Sexual Minority Status and Dating Violence.

Science.gov (United States)

Martin-Storey, Alexa; Fromme, Kim

2017-08-01

Dating violence presents a serious threat for individual health and well-being. A growing body of literature suggests that starting in adolescence, individuals with sexual minority identities (e.g., individuals who identify as gay, lesbian, or bisexual) may be at an increased risk for dating violence compared with heterosexuals. Research has not, however, identified the mechanisms that explain this vulnerability. Using a diverse sample of young adults ( n = 2,474), the current study explored how minority stress theory, revictimization theory, sex of sexual partners, and risky sexual behavior explained differences in dating violence between sexual minority and heterosexual young adults. Initial analyses suggested higher rates of dating violence among individuals who identified as bisexual, and individuals who identified as gay or lesbian when compared with heterosexuals, and further found that these associations failed to differ across gender. When mediating and control variables were included in the analyses, however, the association between both sexual minority identities and higher levels of dating violence became nonsignificant. Of particular interest was the role of discrimination, which mediated the association between bisexual identity and dating violence. Other factors, including sex and number of sexual partners, alcohol use, and childhood maltreatment, were associated with higher rates of dating violence but did not significantly explain vulnerability among sexual minority individuals compared with their heterosexual peers. These findings suggest the importance of minority stress theory in explaining vulnerability to dating violence victimization among bisexuals in particular, and generally support the importance of sexual-minority specific variables in understanding risk for dating violence within this vulnerable population.

Negative plant soil feedback explaining ring formation in clonal plants

NARCIS (Netherlands)

Carteni, F.; Marasco, A.; Bonanomi, G.; Mazzoleni, S.; Rietkerk, M.G.; Giannino, F.

2012-01-01

Ring shaped patches of clonal plants have been reported in different environments, but the mechanisms underlying such pattern formation are still poorly explained. Water depletion in the inner tussocks zone has been proposed as a possible cause, although ring patterns have been also observed in

PISA and High-Performing Education Systems: Explaining Singapore's Education Success

Science.gov (United States)

Deng, Zongyi; Gopinathan, S.

2016-01-01

Singapore's remarkable performance in Programme for International Student Assessment (PISA) has placed it among the world's high-performing education systems (HPES). In the literature on HPES, its "secret formula" for education success is explained in terms of teacher quality, school leadership, system characteristics and educational…

Suspicious minds: explaining political cynicism among political journalists in Europe

NARCIS (Netherlands)

van Dalen, A.; Albæk, E.; de Vreese, C.

2011-01-01

Critics claim that journalists spread a cynical view of politics, as their relation with politicians is characterized by mistrust and hyper-adversarialism. To gain an insight into how cynical journalists themselves are about politics and how this can be explained, this article investigates the role

Macroepizoísmo em Libinia ferreirae (Crustacea, Brachyura, Majidae Macroepizoites on Libinia ferreirae (Crustacea, Brachyura, Majidae

Directory of Open Access Journals (Sweden)

Vanessa C. Winter

2006-06-01

Full Text Available Um estudo de distribuição dos macroepizóicos foi realizado numa população do caranguejo-aranha Libinia ferreirae Brito Capello, 1871 proveniente do litoral dos estados do Paraná e de Santa Catarina. O material biológico foi obtido junto aos pescadores, e faz parte do rejeito de pesca. Os caranguejos foram mensurados e os macroepizóicos identificados e contados. Os seguintes macroepizóicos sésseis foram registrados: Calliactis tricolor (Lesueur, 1817 (Cnidaria; Actiniaria (Cnidaria; Arca sp. (Mollusca; Ostreidae (Mollusca; Acanthodesia tenuis (Desor, 1848 (Bryozoa; Cirripedia e duas espécies tubícolas de Gammaridea (Crustacea. Além destes organismos ocorreram dois tubos desabitados e quatro animais vágeis. A anêmona C. tricolor foi a espécie mais abundante e freqüente, sendo, provavelmente, utilizada como mecanismo de camuflagem pelo caranguejo. O macroepizoísmo em L. ferreirae está relacionado com a idade ou tamanho do caranguejo, tendo maior incidência naqueles mais velhos ou de maior porte. Entretanto, a densidade dos macroepizóicos por caranguejo se mantém em torno de três. Não há relação entre o macroepizoísmo e o sexo do hospedeiro; somente fêmeas ovígeras utilizam desse recurso mais freqüentemente do que as não-ovígeras. Devido à maior área de fixação, os macroepizóicos colonizam principalmente a carapaça do caranguejo, enquanto nos pereiópodos há predominância de Bryozoa.A study of the distribution of the macroepizoites was carried out on a population of the spider crab Libinia ferreirae Brito Capello, 1871 from the Southern Brazilian coast. Crabs were obtained from shrimps and fishes by-catch. They were measured, and their macroepizoites were identified and counted. The following sessile macroepizoites were registered: Calliactis tricolor (Lesueur, 1817 (Cnidaria; Actiniaria (Cnidaria; Arca sp. (Mollusca; Ostreidae (Mollusca; Acanthodesia tenuis (Desor, 1848 (Bryozoa; Cirripedia and two species

Explaining CMS lepton excesses with supersymmetry

CERN Multimedia

CERN. Geneva; Prof. Allanach, Benjamin

2014-01-01

1) Kostas Theofilatos will give an introduction to CMS result 2) Ben Allanach: Several CMS analyses involving di-leptons have recently reported small 2.4-2.8 sigma local excesses: nothing to get too excited about, but worth keeping an eye on nonetheless. In particular, a search in the $lljj p_T$(miss) channel, a search for $W_R$ in the $lljj$ channel and a di-leptoquark search in the $lljj$ channel and $ljj p_T$(miss) channel have all yielded small excesses. We interpret the first excess in the MSSM, showing that the interpretation is viable in terms of other constraints, despite only having squark masses of around 1 TeV. We can explain the last three excesses with a single R-parity violating coupling that predicts a non-zero contribution to the neutrinoless double beta decay rate.

Epigenetics and obesity: a relationship waiting to be explained.

Science.gov (United States)

Symonds, Michael E; Budge, Helen; Frazier-Wood, Alexis C

2013-01-01

Obesity can have multifactorial causes that may change with development and are not simply attributable to one's genetic constitution. To date, expensive and laborious genome-wide association studies have only ascribed a small contribution of genetic variants to obesity. The emergence of the field of epigenetics now offers a new paradigm with which to study excess fat mass. Currently, however, there are no compelling epigenetic studies to explain the role of epigenetics in obesity, especially from a developmental perspective. It is clear that until there are advances in the understanding of the main mechanisms by which different fat types, i.e. brown, beige, and white, are established and how these differ between depots and species, population-based studies designed to determine specific aspects of epigenetics will be potentially limited. Obesity is a slowly evolving condition that is not simply explained by changes in the intake of one macronutrient. The latest advances in epigenetics, coupled with the establishment of relevant longitudinal models of obesity, which incorporate functionally relevant end points, may now permit the precise contribution of epigenetic modifications to excess fat mass to be effectively studied. © 2013 S. Karger AG, Basel.

Explaining Racial Disparities in Infant Health in Brazil

Science.gov (United States)

Nyarko, Kwame A.; Lopez-Camelo, Jorge; Castilla, Eduardo E.

2015-01-01

Objectives. We sought to quantify how socioeconomic, health care, demographic, and geographic effects explain racial disparities in low birth weight (LBW) and preterm birth (PTB) rates in Brazil. Methods. We employed a sample of 8949 infants born between 1995 and 2009 in 15 cities and 7 provinces in Brazil. We focused on disparities in LBW (Public policies to improve children’s health should target prenatal care and geographic location differences to reduce health disparities between infants of African and European ancestries in Brazil. PMID:26313046

Explaining pathological changes in axonal excitability through dynamical analysis of conductance-based models

Science.gov (United States)

Coggan, Jay S.; Ocker, Gabriel K.; Sejnowski, Terrence J.; Prescott, Steven A.

2011-10-01

Neurons rely on action potentials, or spikes, to relay information. Pathological changes in spike generation likely contribute to certain enigmatic features of neurological disease, like paroxysmal attacks of pain and muscle spasm. Paroxysmal symptoms are characterized by abrupt onset and short duration, and are associated with abnormal spiking although the exact pathophysiology remains unclear. To help decipher the biophysical basis for 'paroxysmal' spiking, we replicated afterdischarge (i.e. continued spiking after a brief stimulus) in a minimal conductance-based axon model. We then applied nonlinear dynamical analysis to explain the dynamical basis for initiation and termination of afterdischarge. A perturbation could abruptly switch the system between two (quasi-)stable attractor states: rest and repetitive spiking. This bistability was a consequence of slow positive feedback mediated by persistent inward current. Initiation of afterdischarge was explained by activation of the persistent inward current forcing the system to cross a saddle point that separates the basins of attraction associated with each attractor. Termination of afterdischarge was explained by the attractor associated with repetitive spiking being destroyed. This occurred when ultra-slow negative feedback, such as intracellular sodium accumulation, caused the saddle point and stable limit cycle to collide; in that regard, the active attractor is not truly stable when the slowest dynamics are taken into account. The model also explains other features of paroxysmal symptoms, including temporal summation and refractoriness.

The first record of the Chinese pond mussel Sinanodonta woodiana (Lea, 1834 in Montenegro

Directory of Open Access Journals (Sweden)

Tomović Jelena

2013-01-01

Full Text Available Sinanodonta woodiana (Lea, 1834, Chinese pond mussel (Bivalvia: Unionoida: Unionidae is one of the most invasive aquatic macroinvertebrate species found in Europe. We report the Chinese pond mussel for the first time in Montenegro, in August 2012, in Lake Šasko (Adriatic part of the Central Mediterranean subarea. One specimen of the Chinese pond mussel was observed in a habitat with a predominantly silt-clay substrate. The main pathway of species introduction was evaluated to be via fish stocking. [Projekat Ministarstva nauke Republike Srbije, br. III 43002 i br. ON 173025

Processing of 13C-labelled phytoplankton in a fine-grained sandy-shelf sediment (North Sea): relative importance of different macrofauna species

DEFF Research Database (Denmark)

Kamp, Anja; Witte, Ursula

2005-01-01

by additional laboratory experiments on the role of the dominant macrofauna organism, the bivalve Fabulina fabula (Bivalvia: Tellinidae), for particulate organic matter subduction to deeper sediment layers. The specific uptake of algal 13C by macrofauna organisms was visible after 12 h and constantly increased...... carbon processing. Predatory macrofauna organisms like Nephtys spp. (Polychaeta: Nephtyidae) also quickly became labelled. The rapid subduction of fresh organic matter by F. fabula down to ca. 4 to 7 cm sediment depth could be demonstrated, and it is suggested that entrainment by macrofauna in this fine...

Wealth, wages and wedlock : Explaining the college gender gap reversal

NARCIS (Netherlands)

Reijnders, Laurie

2018-01-01

We study the role of changes in the wage structure and expectations about marriage in explaining the college gender gap reversal. With strongly diminishing marginal utility of wealth and in the presence of a gender wage gap, single women have a greater incentive than single men to invest in

Explaining the Association between Music Training and Reading in Adults

Science.gov (United States)

Swaminathan, Swathi; Schellenberg, E. Glenn; Venkatesan, Kirthika

2018-01-01

We sought to clarify whether the positive association between music lessons and reading ability is explained better by shared resources for processing pitch and temporal information, or by general cognitive abilities. Participants were native and nonnative speakers of English with varying levels of music training. We measured reading ability…

When apperceptive agnosia is explained by a deficit of primary visual processing.

Science.gov (United States)

Serino, Andrea; Cecere, Roberto; Dundon, Neil; Bertini, Caterina; Sanchez-Castaneda, Cristina; Làdavas, Elisabetta

2014-03-01

Visual agnosia is a deficit in shape perception, affecting figure, object, face and letter recognition. Agnosia is usually attributed to lesions to high-order modules of the visual system, which combine visual cues to represent the shape of objects. However, most of previously reported agnosia cases presented visual field (VF) defects and poor primary visual processing. The present case-study aims to verify whether form agnosia could be explained by a deficit in basic visual functions, rather that by a deficit in high-order shape recognition. Patient SDV suffered a bilateral lesion of the occipital cortex due to anoxia. When tested, he could navigate, interact with others, and was autonomous in daily life activities. However, he could not recognize objects from drawings and figures, read or recognize familiar faces. He was able to recognize objects by touch and people from their voice. Assessments of visual functions showed blindness at the centre of the VF, up to almost 5°, bilaterally, with better stimulus detection in the periphery. Colour and motion perception was preserved. Psychophysical experiments showed that SDV's visual recognition deficits were not explained by poor spatial acuity or by the crowding effect. Rather a severe deficit in line orientation processing might be a key mechanism explaining SDV's agnosia. Line orientation processing is a basic function of primary visual cortex neurons, necessary for detecting "edges" of visual stimuli to build up a "primal sketch" for object recognition. We propose, therefore, that some forms of visual agnosia may be explained by deficits in basic visual functions due to widespread lesions of the primary visual areas, affecting primary levels of visual processing. Copyright © 2013 Elsevier Ltd. All rights reserved.

Explaining the democratic anchorage of governance networks

DEFF Research Database (Denmark)

Skelcher, Chris; Klijn, Erik-Hans; Kübler, Daniel

2011-01-01

Advances in understanding the democratic anchorage of governance networks require carefully designed and contextually grounded empirical analysis that take into account contextual factors. The article uses a conjectural framework to study the impact of the national democratic milieu...... on the relationship between network governance and representative institutions in four European countries: the United Kingdom, Switzerland, the Netherlands, and Denmark. The article shows that the distinction between majoritarian and consensus democracy as well as the varying strength of voluntary associations...... are important contextual factors that help explain cross-national differences in the relationship between governance networks and representative institutions. We conclude that a context of weak associationalism in majoritarian democracies facilitates the instrumentalization of networks by government actors...

Can molecular cell biology explain chromosome motions?

Directory of Open Access Journals (Sweden)

Gagliardi L

2011-05-01

Full Text Available Abstract Background Mitotic chromosome motions have recently been correlated with electrostatic forces, but a lingering "molecular cell biology" paradigm persists, proposing binding and release proteins or molecular geometries for force generation. Results Pole-facing kinetochore plates manifest positive charges and interact with negatively charged microtubule ends providing the motive force for poleward chromosome motions by classical electrostatics. This conceptual scheme explains dynamic tracking/coupling of kinetochores to microtubules and the simultaneous depolymerization of kinetochore microtubules as poleward force is generated. Conclusion We question here why cells would prefer complex molecular mechanisms to move chromosomes when direct electrostatic interactions between known bound charge distributions can accomplish the same task much more simply.

Can Science Explain the Human Mind? Intuitive Judgments About the Limits of Science.

Science.gov (United States)

Gottlieb, Sara; Lombrozo, Tania

2018-01-01

Can science explain romantic love, morality, and religious belief? We documented intuitive beliefs about the limits of science in explaining the human mind. We considered both epistemic evaluations (concerning whether science could possibly fully explain a given psychological phenomenon) and nonepistemic judgments (concerning whether scientific explanations for a given phenomenon would generate discomfort), and we identified factors that characterize phenomena judged to fall beyond the scope of science. Across six studies, we found that participants were more likely to judge scientific explanations for psychological phenomena to be impossible and uncomfortable when, among other factors, they support first-person, introspective access (e.g., feeling empathetic as opposed to reaching for objects), contribute to making humans exceptional (e.g., appreciating music as opposed to forgetfulness), and involve conscious will (e.g., acting immorally as opposed to having headaches). These judgments about the scope of science have implications for science education, policy, and the public reception of psychological science.

Effects of CO-60 gamma radiation on the embryonary development of Biomphalaria Glabrata (Say, 1818)

International Nuclear Information System (INIS)

Okazaki, K.

1988-01-01

Some aspects of the effects of the ionizing radiation on the embryo and on the genetical material of Biomphalaria glabrata (Mollusca: Gastropoda) are presented. The embryos weresubmitted at various stages of development to doses of 5,10,15,20 and 25 Gy of Co-60 gamma radiation. As a criteia of evaluation of the embryos radiosensitivity, four biological parameters were used: mortality, malformation, hatching and chromossomal aberrations. (M.A.C.) [pt

Larval trematodes (Digenea) of the great pond snail, Lymnaea stagnalis (L.), (Gastropoda, Pulmonata) in Central Europe: a survey of species and key to their identification

Czech Academy of Sciences Publication Activity Database

Faltýnková, Anna; Našincová, Vanda; Kablásková, Lenka

2007-01-01

Roč. 14, č. 1 (2007), s. 39-51 ISSN 1252-607X R&D Projects: GA AV ČR IAA6022404; GA ČR GP524/07/P086; GA ČR GD524/03/H133; GA MŠk LC522 Institutional research plan: CEZ:AV0Z60220518 Keywords : Trematoda * Mollusca * cercaria * metacercaria * Lymnaea stagnalis Subject RIV: EG - Zoology Impact factor: 0.713, year: 2007

Physiological and biochemical responses to cold and drought in the rock-dwelling pulmonate snail, Chondrina avenacea

Czech Academy of Sciences Publication Activity Database

Košťál, Vladimír; Rozsypal, Jan; Pech, P.; Zahradníčková, Helena; Šimek, Petr

2013-01-01

Roč. 183, č. 6 (2013), s. 749-761 ISSN 0174-1578 R&D Projects: GA ČR GA206/07/0269; GA MZd(CZ) NT11513 Grant - others:GA JU(CZ) 04-062/2011/P Institutional support: RVO:60077344 Keywords : Mollusca * estivation * hibermation Subject RIV: ED - Physiology Impact factor: 2.530, year: 2013 http://link.springer.com/content/pdf/10.1007%2Fs00360-013-0749-0.pdf

Enlightenment of old ideas from new investigations: more questions regarding the evolution of bacteriogenic light organs in squids

OpenAIRE

Nishiguchi, M. K.; Lopez, J. E.; Boletzky, S. v.

2004-01-01

Bioluminescence is widespread among many different types of marine organisms. Metazoans contain two types of luminescence production, bacteriogenic (symbiotic with bacteria) or autogenic, via the production of a luminous secretion or the intrinsic properties of luminous cells. Several species in two families of squids, the Loliginidae and the Sepiolidae (Mollusca: Cephalopoda) harbor bacteriogenic light organs that are found central in the mantle cavity. These light organs are exceptional in ...

Explaining the Effects of Communities of Pastoral Care for Students

Science.gov (United States)

Murphy, Joseph; Holste, Linda

2016-01-01

This article explains how communities of pastoral care work. It presents an empirically forged theory in action. We examined theoretical and empirical work across the targeted area of personalization for students. We also completed what Hallinger (2012) refers to as "exhaustive review" of the field of school improvement writ large. We…

Recognizing, explaining and countering norm transgressive behaviour on social media

NARCIS (Netherlands)

Padje, E.D.H.

2016-01-01

In this thesis, it is researched how norm transgressive behaviour exhibited on the Dutch domains of social media can be recognized, explained and countered. An analysis of four comment threads is conducted, of which the comments can be found on the Facebook pages of three Dutch news sites and on a

Explaining Self-Harm: Youth Cybertalk and Marginalized Sexualities and Genders

Science.gov (United States)

McDermott, Elizabeth; Roen, Katrina; Piela, Anna

2015-01-01

This study investigates self-harm among young lesbian, gay, bisexual, and trans (LGBT) people. Using qualitative virtual methods, we examined online forums to explore young LGBT people's cybertalk about emotional distress and self-harming. We investigated how youth explained the relationship between self-harm and sexuality and gender. We found…

Biogeographical homogeneity in the eastern Mediterranean Sea - I: the opisthobranchs (Mollusca: Gastropoda from Lebanon

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F. CROCETTA

2013-07-01

Full Text Available A reviewed knowledge of the opisthobranch species from Lebanon (eastern Mediterranean Sea, based on literature records (scattered throughout various papers published over a period of more than 150 years and recently collected material (1999-2002 within the CEDRE framework and other samples, is presented, yielding a total number of 35 taxa recorded from the Lebanese shores identified to species level. Special emphasis has mainly been given to the alien species, for which scattered notes are also given. The known opisthobranch biota is composed of 22 native (~ 63%, 12 alien (~ 34% and one cryptogenic (~ 3% taxa. Eleven of these (Berthella aurantiaca, B. ocellata, Aplysia fasciata, Felimare picta, Felimida britoi, F. luteorosea, F. purpurea, Phyllidia flava, Dendrodoris grandiflora, D. limbata and Aeolidiella alderi constitute new records for the Lebanese fauna, whilst the examined material of a further seven species (Elysia grandifolia, Pleurobranchus forskalii, Aplysia dactylomela, Bursatella leachii, Syphonota geographica, Goniobranchus annulatus, Flabellina rubrolineata anecdotally cited from Lebanon on the basis of the samples here studied, is here first explained. One additional taxon belonging to the genus Haminoea has been identified to genus level only. Despite the searching effort poning the basis of the material analyzed here, data reported clearly suggest that strong investments are still needed for a better understanding of the eastern Mediterranean opisthobranch fauna.

Extending Social Learning Theory to Explain Victimization Among Gang and Ex-Gang Offenders.

Science.gov (United States)

Gagnon, Analisa

2018-03-01

This study is among the first to extend and test social learning theory's ability to understand property and violent victimization. It specifically tests whether aspects of definitions, differential reinforcement, and differential association/modeling can explain the three types of victimization of gang members: actual experience, perception of likelihood, and fear. The sample consists of over 300 male and female gang members incarcerated in jails throughout Florida. The results show that all three types of victimization can be explained by the three aspects of social learning theory.

Learning to Apply Models of Materials While Explaining Their Properties

Science.gov (United States)

Karpin, Tiia; Juuti, Kalle; Lavonen, Jari

2014-01-01

Background: Applying structural models is important to chemistry education at the upper secondary level, but it is considered one of the most difficult topics to learn. Purpose: This study analyses to what extent in designed lessons students learned to apply structural models in explaining the properties and behaviours of various materials.…

Does Discrimination Explain High Risk of Depression among High-Income African American Men?

Science.gov (United States)

Assari, Shervin; Lankarani, Maryam Moghani; Caldwell, Cleopatra Howard

2018-04-19

Background: Higher socioeconomic status is known to decrease the risk for poor mental health overall. However, African American males of higher socioeconomic status (SES) are at an increased risk for having a major depressive episode (MDE). It is not known whether perceived discrimination (PD) explains this risk. The current study used nationally representative data to explore the role of PD in explaining the association between high-SES and having MDE among African American men. Methods: The National Survey of American Life (NSAL), 2003, included 4461 American adults including 1271 African American men. SES indicators (i.e., household income, educational attainment, employment status, and marital status) were the independent variables. 12-month MDE measured using the Composite International Diagnostic Interview (CIDI) was the outcome. Age, gender, and region were the covariates. PD was the potential mediator. For data analysis, we used logistic regression. Results: Among African American men, household income was positively associated with odds of 12-month MDE. The positive association between household income and odds of MDE remained unchanged after adding PD to the model, suggesting that PD may not explain why high-income African American men are at a higher risk of MDE. Conclusions: Perceived discrimination does not explain the increased risk for depression among African American males of higher SES. Future research should explore the role of other potential mechanisms such as stress, coping, social isolation, and/or negative social interaction that may increase psychological costs of upward social mobility for African American males.

Interannual variability of net ecosystem productivity in forests is explained by carbon flux phenology in autumn

DEFF Research Database (Denmark)

Wu, Chaoyang; Chen, Xi Jing; Black, T. Andrew

2013-01-01

To investigate the importance of autumn phenology in controlling interannual variability of forest net ecosystem productivity (NEP) and to derive new phenological metrics to explain the interannual variability of NEP. North America and Europe. Flux data from nine deciduous broadleaf forests (DBF......, soil water content and precipitation, were also used to explain the phenological variations. We found that interannual variability of NEP can be largely explained by autumn phenology, i.e. the autumn lag. While variation in neither annual gross primary productivity (GPP) nor in annual ecosystem...

Coin Tossing Explains the Activity of Opposing Microtubule Motors on Phagosomes.

Science.gov (United States)

Sanghavi, Paulomi; D'Souza, Ashwin; Rai, Ashim; Rai, Arpan; Padinhatheeri, Ranjith; Mallik, Roop

2018-05-07

How the opposing activity of kinesin and dynein motors generates polarized distribution of organelles inside cells is poorly understood and hotly debated [1, 2]. Possible explanations include stochastic mechanical competition [3, 4], coordinated regulation by motor-associated proteins [5-7], mechanical activation of motors [8], and lipid-induced organization [9]. Here, we address this question by using phagocytosed latex beads to generate early phagosomes (EPs) that move bidirectionally along microtubules (MTs) in an in vitro assay [9]. Dynein/kinesin activity on individual EPs is recorded as real-time force generation of the motors against an optical trap. Activity of one class of motors frequently coincides with, or is rapidly followed by opposite motors. This leads to frequent and rapid reversals of EPs in the trap. Remarkably, the choice between dynein and kinesin can be explained by the tossing of a coin. Opposing motors therefore appear to function stochastically and independently of each other, as also confirmed by observing no effect on kinesin function when dynein is inhibited on the EPs. A simple binomial probability calculation based on the geometry of EP-microtubule contact explains the observed activity of dynein and kinesin on phagosomes. This understanding of intracellular transport in terms of a hypothetical coin, if it holds true for other cargoes, provides a conceptual framework to explain the polarized localization of organelles inside cells. Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Can model-free reinforcement learning explain deontological moral judgments?

Science.gov (United States)

Ayars, Alisabeth

2016-05-01

Dual-systems frameworks propose that moral judgments are derived from both an immediate emotional response, and controlled/rational cognition. Recently Cushman (2013) proposed a new dual-system theory based on model-free and model-based reinforcement learning. Model-free learning attaches values to actions based on their history of reward and punishment, and explains some deontological, non-utilitarian judgments. Model-based learning involves the construction of a causal model of the world and allows for far-sighted planning; this form of learning fits well with utilitarian considerations that seek to maximize certain kinds of outcomes. I present three concerns regarding the use of model-free reinforcement learning to explain deontological moral judgment. First, many actions that humans find aversive from model-free learning are not judged to be morally wrong. Moral judgment must require something in addition to model-free learning. Second, there is a dearth of evidence for central predictions of the reinforcement account-e.g., that people with different reinforcement histories will, all else equal, make different moral judgments. Finally, to account for the effect of intention within the framework requires certain assumptions which lack support. These challenges are reasonable foci for future empirical/theoretical work on the model-free/model-based framework. Copyright © 2016 Elsevier B.V. All rights reserved.

An attempt to explain the uranium 238 effective capture integral discrepancy

International Nuclear Information System (INIS)

Tellier, Henry; Grandotto-Biettoli, Marc; Vanuxeem, Jacqueline

1979-02-01

Up to now, there was a discrepancy between the computed value and the measured value of the uranium 238 effective capture integral. The former has been always greater than the latter. For this reason, the reactor physicists have used an adjustment of the computed value. Nowadays the accuracy of the cross sections knowledge is increased and the reactors computation codes are almost exact. Such an adjustment is no more justified. Recently several new measurements of the resonance parameters were carried out and the use of a multilevel formalism was suggested to compute the uranium 238 cross sections. It is shown in this work that the simultaneous use of recent parameters and Reich and Moore formalism explain the discrepancy. For the thermal neutron reactors, two thirds of this discrepancy are explained by the neutron data and the last third by the multilevel formalism [fr

Explaining the moral of the story.

Science.gov (United States)

Walker, Caren M; Lombrozo, Tania

2017-10-01

Although storybooks are often used as pedagogical tools for conveying moral lessons to children, the ability to spontaneously extract "the moral" of a story develops relatively late. Instead, children tend to represent stories at a concrete level - one that highlights surface features and understates more abstract themes. Here we examine the role of explanation in 5- and 6-year-old children's developing ability to learn the moral of a story. Two experiments demonstrate that, relative to a control condition, prompts to explain aspects of a story facilitate children's ability to override salient surface features, abstract the underlying moral, and generalize that moral to novel contexts. In some cases, generating an explanation is more effective than being explicitly told the moral of the story, as in a more traditional pedagogical exchange. These findings have implications for moral comprehension, the role of explanation in learning, and the development of abstract reasoning in early childhood. Copyright © 2016 Elsevier B.V. All rights reserved.

Individual Movement Variability Magnitudes Are Explained by Cortical Neural Variability.

Science.gov (United States)

Haar, Shlomi; Donchin, Opher; Dinstein, Ilan

2017-09-13

Humans exhibit considerable motor variability even across trivial reaching movements. This variability can be separated into specific kinematic components such as extent and direction that are thought to be governed by distinct neural processes. Here, we report that individual subjects (males and females) exhibit different magnitudes of kinematic variability, which are consistent (within individual) across movements to different targets and regardless of which arm (right or left) was used to perform the movements. Simultaneous fMRI recordings revealed that the same subjects also exhibited different magnitudes of fMRI variability across movements in a variety of motor system areas. These fMRI variability magnitudes were also consistent across movements to different targets when performed with either arm. Cortical fMRI variability in the posterior-parietal cortex of individual subjects explained their movement-extent variability. This relationship was apparent only in posterior-parietal cortex and not in other motor system areas, thereby suggesting that individuals with more variable movement preparation exhibit larger kinematic variability. We therefore propose that neural and kinematic variability are reliable and interrelated individual characteristics that may predispose individual subjects to exhibit distinct motor capabilities. SIGNIFICANCE STATEMENT Neural activity and movement kinematics are remarkably variable. Although intertrial variability is rarely studied, here, we demonstrate that individual human subjects exhibit distinct magnitudes of neural and kinematic variability that are reproducible across movements to different targets and when performing these movements with either arm. Furthermore, when examining the relationship between cortical variability and movement variability, we find that cortical fMRI variability in parietal cortex of individual subjects explained their movement extent variability. This enabled us to explain why some subjects

Does cultural integration explain a mental health advantage for adolescents?

Science.gov (United States)

Bhui, Kamaldeep S; Lenguerrand, Erik; Maynard, Maria J; Stansfeld, Stephen A; Harding, Seeromanie

2012-06-01

A mental health advantage has been observed among adolescents in urban areas. This prospective study tests whether cultural integration measured by cross-cultural friendships explains a mental health advantage for adolescents. A prospective cohort of adolescents was recruited from 51 secondary schools in 10 London boroughs. Cultural identity was assessed by friendship choices within and across ethnic groups. Cultural integration is one of four categories of cultural identity. Using gender-specific linear-mixed models we tested whether cultural integration explained a mental health advantage, and whether gender and age were influential. Demographic and other relevant factors, such as ethnic group, socio-economic status, family structure, parenting styles and perceived racism were also measured and entered into the models. Mental health was measured by the Strengths and Difficulties Questionnaire as a 'total difficulties score' and by classification as a 'probable clinical case'. A total of 6643 pupils in first and second years of secondary school (ages 11-13 years) took part in the baseline survey (2003/04) and 4785 took part in the follow-up survey in 2005-06. Overall mental health improved with age, more so in male rather than female students. Cultural integration (friendships with own and other ethnic groups) was associated with the lowest levels of mental health problems especially among male students. This effect was sustained irrespective of age, ethnicity and other potential explanatory variables. There was a mental health advantage among specific ethnic groups: Black Caribbean and Black African male students (Nigerian/Ghanaian origin) and female Indian students. This was not fully explained by cultural integration, although cultural integration was independently associated with better mental health. Cultural integration was associated with better mental health, independent of the mental health advantage found among specific ethnic groups: Black Caribbean and

Does cultural integration explain a mental health advantage for adolescents?

Science.gov (United States)

Bhui, Kamaldeep S; Lenguerrand, Erik; Maynard, Maria J; Stansfeld, Stephen A; Harding, Seeromanie

2012-01-01

Background A mental health advantage has been observed among adolescents in urban areas. This prospective study tests whether cultural integration measured by cross-cultural friendships explains a mental health advantage for adolescents. Methods A prospective cohort of adolescents was recruited from 51 secondary schools in 10 London boroughs. Cultural identity was assessed by friendship choices within and across ethnic groups. Cultural integration is one of four categories of cultural identity. Using gender-specific linear-mixed models we tested whether cultural integration explained a mental health advantage, and whether gender and age were influential. Demographic and other relevant factors, such as ethnic group, socio-economic status, family structure, parenting styles and perceived racism were also measured and entered into the models. Mental health was measured by the Strengths and Difficulties Questionnaire as a ‘total difficulties score’ and by classification as a ‘probable clinical case’. Results A total of 6643 pupils in first and second years of secondary school (ages 11–13 years) took part in the baseline survey (2003/04) and 4785 took part in the follow-up survey in 2005–06. Overall mental health improved with age, more so in male rather than female students. Cultural integration (friendships with own and other ethnic groups) was associated with the lowest levels of mental health problems especially among male students. This effect was sustained irrespective of age, ethnicity and other potential explanatory variables. There was a mental health advantage among specific ethnic groups: Black Caribbean and Black African male students (Nigerian/Ghanaian origin) and female Indian students. This was not fully explained by cultural integration, although cultural integration was independently associated with better mental health. Conclusions Cultural integration was associated with better mental health, independent of the mental health advantage

What We Don't Understand, We Explain to Each Other

Science.gov (United States)

Pines, David

2015-01-01

"What we don't understand, we explain to each other" was Robert Oppenheimer's 1948 description of theoretical physics as a profession. Because the phrase connects research, teaching, and learning, it seemed the right approach for the talk I gave to the AAPT [American Association of Physics Teachers] on receiving the 2013 J.D. Jackson…

Explaining anomalies in intertemporal choice : a mental zooming theory

OpenAIRE

Holden, Stein Terje

2014-01-01

I present a theory that can explain hyperbolic discounting and magnitude effects in intertemporal choice. This approach builds on theories of narrow framing and reference dependence and expands these theories in a novel way by examining hidden mental zooming in base consumption adjustment in decisions regarding intertemporal prospects of varying magnitudes and time horizons. Data from a field experiment were used to assess the theory with an incentivecompatible multiple price list approach in...

Do mirror neurons explain misattribution of emotions in music?

Science.gov (United States)

Gridley, Mark C; Hoff, Robert

2006-04-01

It is speculated that certain listeners' misattribution of anger in the music of avant garde jazz saxophonists could be explained by the activity of mirror neurons. There is a neurological basis for the human tendency to imitate what is perceived in another person. This may lead to an inference that whatever comparable activity would be required to achieve a similar condition in the imitator is the condition being experienced by the person being imitated.

Island phytophagy: explaining the remarkable diversity of plant-feeding insects.

Science.gov (United States)

Joy, Jeffrey B; Crespi, Bernard J

2012-08-22

Plant-feeding insects have undergone unparalleled diversification among different plant taxa, yet explanations for variation in their diversity lack a quantitative, predictive framework. Island biogeographic theory has been applied to spatially discrete habitats but not to habitats, such as host plants, separated by genetic distance. We show that relationships between the diversity of gall-inducing flies and their host plants meet several fundamental predictions from island biogeographic theory. First, plant-taxon genetic distinctiveness, an integrator for long-term evolutionary history of plant lineages, is a significant predictor of variance in the diversity of gall-inducing flies among host-plant taxa. Second, range size and structural complexity also explain significant proportions of the variance in diversity of gall-inducing flies among different host-plant taxa. Third, as with other island systems, plant-lineage age does not predict species diversity. Island biogeographic theory, applied to habitats defined by genetic distance, provides a novel, comprehensive framework for analysing and explaining the diversity of plant-feeding insects and other host-specific taxa.

Self-Interacting Dark Matter Can Explain Diverse Galactic Rotation Curves.

Science.gov (United States)

Kamada, Ayuki; Kaplinghat, Manoj; Pace, Andrew B; Yu, Hai-Bo

2017-09-15

The rotation curves of spiral galaxies exhibit a diversity that has been difficult to understand in the cold dark matter (CDM) paradigm. We show that the self-interacting dark matter (SIDM) model provides excellent fits to the rotation curves of a sample of galaxies with asymptotic velocities in the 25-300  km/s range that exemplify the full range of diversity. We assume only the halo concentration-mass relation predicted by the CDM model and a fixed value of the self-interaction cross section. In dark-matter-dominated galaxies, thermalization due to self-interactions creates large cores and reduces dark matter densities. In contrast, thermalization leads to denser and smaller cores in more luminous galaxies and naturally explains the flatness of rotation curves of the highly luminous galaxies at small radii. Our results demonstrate that the impact of the baryons on the SIDM halo profile and the scatter from the assembly history of halos as encoded in the concentration-mass relation can explain the diverse rotation curves of spiral galaxies.

Use of retractors and explainers in charismatic rhetoric: the case of four American presidents

Directory of Open Access Journals (Sweden)

Iaroslav Kovalchuk

2013-05-01

Full Text Available This study examines the use of retractors and explainers in prepared political speeches of American charismatic presidents. It is based upon the results of psychological analysis of 24 speeches of John F. Kennedy, Ronald Reagan, Barack Obama, and Gerald Ford. The research shows that certain differences may be found in the use of explainers and retractors not along the axis “Charismatic versus Non-Charismatic Presidents”, but with regard to their party affiliation. Rhetoric of Democratic presidents (Kennedy, Obama is characterized by a more explanatory communication style than of Republican ones (Reagan, Ford, which results in respective differences in the use of explainers. As for the retractors, all the four presidents under study tend to use the category moderately, which reveals them as emotionally controlled individuals, able to reconsider their decisions if necessary.

The attribution of work environment in explaining gender differences in long-term sickness absence

DEFF Research Database (Denmark)

Labriola, Merete; Holte, Kari Anne; Christensen, Karl Bang

2011-01-01

. Conclusion Differences in psychosocial work environments in terms of emotional demands, reward at work, management quality and role conflicts, explained roughly 30% of women's excess long-term sickness absence risk. Assuming women and men had identical working conditions would leave the larger part......Objectives To identify differences in risk of long-term sickness absence between female and male employees in Denmark and to examine to what extent differences could be explained by work environment factors. Methods A cohort of 5026 employees (49.1% women, mean age 40.4 years; 50.9% men, mean age....... Results 298 workers (5.9%) received sickness absence compensation for 8 weeks or more. Women had an excess risk of 37% compared to men, when adjusting for age, family status and socio-economic position. Physical work environment exposures could not explain this difference, whereas differences...

Body Composition Explains Sex Differential in Physical Performance Among Older Adults

NARCIS (Netherlands)

Tseng, L.A.; Delmonico, M.J.; Visser, M.; Boudreau, R.M.; Goodpaster, B.H.; Schwartz, A.V.; Simonsick, E.M.; Satterfield, S.; Harris, T.; Newman, A.B.

2014-01-01

Background. Older women have higher percent body fat, poorer physical function, lower strength, and higher rates of nonfatal chronic conditions than men. We sought to determine whether these differences explained physical performance differences between men and women. Methods. Physical performance

Why did I do that? : Explaining Actions Activated Outside of Awareness

NARCIS (Netherlands)

Gantman, A; Adriaanse, M.A.; Gollwitzer, P.M; Oettingen, G

2017-01-01

We review the latest research investigating how people explain their own actions when they have been activated nonconsciously. We will discuss evidence that when nonconsciously activated behavior is unexpected (e.g., normviolating, against self -standards), negative affect arises and triggers

A Model of How Different Biology Experts Explain Molecular and Cellular Mechanisms

Science.gov (United States)

Trujillo, Caleb M.; Anderson, Trevor R.; Pelaez, Nancy J.

2015-01-01

Constructing explanations is an essential skill for all science learners. The goal of this project was to model the key components of expert explanation of molecular and cellular mechanisms. As such, we asked: What is an appropriate model of the components of explanation used by biology experts to explain molecular and cellular mechanisms? Do explanations made by experts from different biology subdisciplines at a university support the validity of this model? Guided by the modeling framework of R. S. Justi and J. K. Gilbert, the validity of an initial model was tested by asking seven biologists to explain a molecular mechanism of their choice. Data were collected from interviews, artifacts, and drawings, and then subjected to thematic analysis. We found that biologists explained the specific activities and organization of entities of the mechanism. In addition, they contextualized explanations according to their biological and social significance; integrated explanations with methods, instruments, and measurements; and used analogies and narrated stories. The derived methods, analogies, context, and how themes informed the development of our final MACH model of mechanistic explanations. Future research will test the potential of the MACH model as a guiding framework for instruction to enhance the quality of student explanations. PMID:25999313

Structural analysis of the α subunit of Na(+)/K(+) ATPase genes in invertebrates.

Science.gov (United States)

Thabet, Rahma; Rouault, J-D; Ayadi, Habib; Leignel, Vincent

2016-01-01

The Na(+)/K(+) ATPase is a ubiquitous pump coordinating the transport of Na(+) and K(+) across the membrane of cells and its role is fundamental to cellular functions. It is heteromer in eukaryotes including two or three subunits (α, β and γ which is specific to the vertebrates). The catalytic functions of the enzyme have been attributed to the α subunit. Several complete α protein sequences are available, but only few gene structures were characterized. We identified the genomic sequences coding the α-subunit of the Na(+)/K(+) ATPase, from the whole-genome shotgun contigs (WGS), NCBI Genomes (chromosome), Genomic Survey Sequences (GSS) and High Throughput Genomic Sequences (HTGS) databases across distinct phyla. One copy of the α subunit gene was found in Annelida, Arthropoda, Cnidaria, Echinodermata, Hemichordata, Mollusca, Placozoa, Porifera, Platyhelminthes, Urochordata, but the nematodes seem to possess 2 to 4 copies. The number of introns varied from 0 (Platyhelminthes) to 26 (Porifera); and their localization and length are also highly variable. Molecular phylogenies (Maximum Likelihood and Maximum Parsimony methods) showed some clusters constituted by (Chordata/(Echinodermata/Hemichordata)) or (Plathelminthes/(Annelida/Mollusca)) and a basal position for Porifera. These structural analyses increase our knowledge about the evolutionary events of the α subunit genes in the invertebrates. Copyright © 2016 Elsevier Inc. All rights reserved.

Science and Technology Pre-Service Teachers' Tendencies to Explain Vitality

Science.gov (United States)

Ozdemir, Oguz

2012-01-01

The present study was carried out to determine the Science and Technology pre-service teachers' tendencies to explain vitality in a university located in Southeast Anatolia of Turkey in 2010-2011 academic year. The data were collected through the administration of a questionnaire developed by the researcher to 1st and 4th year Science and…

Stunting of the penis in Heleobia parchappii (Mollusca: Cochliopidae) and its relationship with parasitism.

Science.gov (United States)

Merlo, Matías J; Parietti, Manuela; Etchegoin, Jorge A

2017-02-08

Penis anatomy is used to discriminate species of gastropods belonging to the family Cochliopidae; however, this characteristic may be affected by the presence of parasites. To evaluate the possible effect of parasites on penis length and number of papillae in Heleobia parchappii, 195 males were collected from the Nahuel Rucá Lagoon, Argentina. Male snails were only infected by trematode digeneans (total prevalence 45.13%). Three out of 9 species of digeneans registered showed prevalence values higher than 10%: Microphallus szidati, M. simillimus, and Notocotylidae sp. 1. The penis length of non-parasitized males and those parasitized by M. szidati and M. similimus increased with increased snail length; however, this increase was lower in infected snails. In the case of snails infected with Notocotylidae sp. 1, no relationship between shell length and penis length was apparent. Differences in the life cycles of these 3 digeneans could explain the null or lower penis growth rate in relation to host body growth. In contrast, no change was observed in the number of penial papillae of H. parchappii when these snails were infected by larval digeneans compared to those that were not infected. This indicates that penial papillae may be a more stable characteristic than penis length to discriminate between species within the Cochliopidae. The study of penial papillae should be central in the taxonomy and identification of new species within the Cochliopidae, as well as in previously described species.

Does Discrimination Explain High Risk of Depression among High-Income African American Men?

Directory of Open Access Journals (Sweden)

Shervin Assari

2018-04-01

Full Text Available Background: Higher socioeconomic status is known to decrease the risk for poor mental health overall. However, African American males of higher socioeconomic status (SES are at an increased risk for having a major depressive episode (MDE. It is not known whether perceived discrimination (PD explains this risk. The current study used nationally representative data to explore the role of PD in explaining the association between high-SES and having MDE among African American men. Methods: The National Survey of American Life (NSAL, 2003, included 4461 American adults including 1271 African American men. SES indicators (i.e., household income, educational attainment, employment status, and marital status were the independent variables. 12-month MDE measured using the Composite International Diagnostic Interview (CIDI was the outcome. Age, gender, and region were the covariates. PD was the potential mediator. For data analysis, we used logistic regression. Results: Among African American men, household income was positively associated with odds of 12-month MDE. The positive association between household income and odds of MDE remained unchanged after adding PD to the model, suggesting that PD may not explain why high-income African American men are at a higher risk of MDE. Conclusions: Perceived discrimination does not explain the increased risk for depression among African American males of higher SES. Future research should explore the role of other potential mechanisms such as stress, coping, social isolation, and/or negative social interaction that may increase psychological costs of upward social mobility for African American males.

Narrowing the Gap: Explaining the Increasing Competitiveness of the Venezuelan Opposition

NARCIS (Netherlands)

Krouwel, A.P.M.; Kutiyski, Y.

2014-01-01

This article seeks to explain why electoral support for the Venezuelan opposition has increased substantially, using Venezuelan public opinion survey data from LAPOP and an opt-in sample collected through the online vote advice application Brújula Presidencial Venezuela. It analyzes why Venezuelans

How Much of Language Acquisition Does Operant Conditioning Explain?

OpenAIRE

Sturdy, Christopher B.; Nicoladis, Elena

2017-01-01

Since the 1950s, when Chomsky argued that Skinner’s arguments could not explain syntactic acquisition, psychologists have generally avoided explicitly invoking operant or instrumental conditioning as a learning mechanism for language among human children. In this article, we argue that this is a mistake. We focus on research that has been done on language learning in human infants and toddlers in order to illustrate our points. Researchers have ended up inventing learning mechanisms that, in ...

Can Equity Volatility Explain the Global Loan Pricing Puzzle?

OpenAIRE

Lewis Gaul; Pinar Uysal

2013-01-01

This paper examines whether unobservable differences in firm volatility are responsible for the global loan pricing puzzle, which is the observation that corporate loan interest rates appear to be lower in Europe than in the United States. We analyze whether equity volatility, an error prone measure of firm volatility, can explain this difference in loan spreads. We show that using equity volatility in OLS regressions will result in biased and inconsistent estimates of the difference in U.S. ...

A father effect explains sex-ratio bias.

Science.gov (United States)

Malo, Aurelio F; Martinez-Pastor, Felipe; Garcia-Gonzalez, Francisco; Garde, Julián; Ballou, Jonathan D; Lacy, Robert C

2017-08-30

Sex ratio allocation has important fitness consequences, and theory predicts that parents should adjust offspring sex ratio in cases where the fitness returns of producing male and female offspring vary. The ability of fathers to bias offspring sex ratios has traditionally been dismissed given the expectation of an equal proportion of X- and Y-chromosome-bearing sperm (CBS) in ejaculates due to segregation of sex chromosomes at meiosis. This expectation has been recently refuted. Here we used Peromyscus leucopus to demonstrate that sex ratio is explained by an exclusive effect of the father, and suggest a likely mechanism by which male-driven sex-ratio bias is attained. We identified a male sperm morphological marker that is associated with the mechanism leading to sex ratio bias; differences among males in the sperm nucleus area (a proxy for the sex chromosome that the sperm contains) explain 22% variation in litter sex ratio. We further show the role played by the sperm nucleus area as a mediator in the relationship between individual genetic variation and sex-ratio bias. Fathers with high levels of genetic variation had ejaculates with a higher proportion of sperm with small nuclei area. This, in turn, led to siring a higher proportion of sons (25% increase in sons per 0.1 decrease in the inbreeding coefficient). Our results reveal a plausible mechanism underlying unexplored male-driven sex-ratio biases. We also discuss why this pattern of paternal bias can be adaptive. This research puts to rest the idea that father contribution to sex ratio variation should be disregarded in vertebrates, and will stimulate research on evolutionary constraints to sex ratios-for example, whether fathers and mothers have divergent, coinciding, or neutral sex allocation interests. Finally, these results offer a potential explanation for those intriguing cases in which there are sex ratio biases, such as in humans. © 2017 The Author(s).

Explaining evolution via constrained persistent perfect phylogeny

Science.gov (United States)

2014-01-01

Background The perfect phylogeny is an often used model in phylogenetics since it provides an efficient basic procedure for representing the evolution of genomic binary characters in several frameworks, such as for example in haplotype inference. The model, which is conceptually the simplest, is based on the infinite sites assumption, that is no character can mutate more than once in the whole tree. A main open problem regarding the model is finding generalizations that retain the computational tractability of the original model but are more flexible in modeling biological data when the infinite site assumption is violated because of e.g. back mutations. A special case of back mutations that has been considered in the study of the evolution of protein domains (where a domain is acquired and then lost) is persistency, that is the fact that a character is allowed to return back to the ancestral state. In this model characters can be gained and lost at most once. In this paper we consider the computational problem of explaining binary data by the Persistent Perfect Phylogeny model (referred as PPP) and for this purpose we investigate the problem of reconstructing an evolution where some constraints are imposed on the paths of the tree. Results We define a natural generalization of the PPP problem obtained by requiring that for some pairs (character, species), neither the species nor any of its ancestors can have the character. In other words, some characters cannot be persistent for some species. This new problem is called Constrained PPP (CPPP). Based on a graph formulation of the CPPP problem, we are able to provide a polynomial time solution for the CPPP problem for matrices whose conflict graph has no edges. Using this result, we develop a parameterized algorithm for solving the CPPP problem where the parameter is the number of characters. Conclusions A preliminary experimental analysis shows that the constrained persistent perfect phylogeny model allows to

Explaining life history variation in a changing climate across a species' range

DEFF Research Database (Denmark)

Neuheimer, Anna B.; MacKenzie, Brian R.

2014-01-01

Timing of reproduction greatly influences offspring success and resulting population production. Explaining and predicting species' dynamics necessitates disentangling the intrinsic (genotypic) and extrinsic (climatic) factors controlling reproductive timing. Here we explore temporal and spatial...... changes in spawning time for 21 populations of Atlantic cod (Gadus morhua) across the species' range (40 degrees to 80 degrees N). We estimate spawning time using a physiologically relevant metric that includes information on fish thermal history (degree-days, DD). First, we estimate spawning DD among...... years (within populations) to show how recent changes in spawning time can be explained by local changes in temperature. Second, we employ spawning DD to identify temperature-independent trends in spawning time among populations that are consistent with parallel adaptive evolution and the evolutionary...

What explains high plant richness in East Asia? Time and diversification in the tribe Lysimachieae (Primulaceae).

Science.gov (United States)

Yan, Hai-Fei; Zhang, Cai-Yun; Anderberg, Arne A; Hao, Gang; Ge, Xue-Jun; Wiens, John J

2018-04-17

What causes the disparity in biodiversity among regions is a fundamental question in biogeography, ecology, and evolutionary biology. Evolutionary and biogeographic processes (speciation, extinction, dispersal) directly determine species richness patterns, and can be studied using integrative phylogenetic approaches. However, the strikingly high richness of East Asia relative to other Northern Hemisphere regions remains poorly understood from this perspective. Here, for the first time, we test two general hypotheses (older colonization time, faster diversification rate) to explain this pattern, using the plant tribe Lysimachieae (Primulaceae) as a model system. We generated a new time-calibrated phylogeny for Lysimachieae (13 genes, 126 species), to estimate colonization times and diversification rates for each region and to test the relative importance of these two factors for explaining regional richness patterns. We find that neither time nor diversification rates alone explain richness patterns among regions in Lysimachieae. Instead, a new index that combines both factors explains global richness patterns in the group and their high East Asian biodiversity. Based on our results from Lysimachieae, we suggest that the high richness of plants in East Asia may be explained by a combination of older colonization times and faster diversification rates in this region. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

Balancing friends and foes : Explaining advocacy styles at global diplomatic conferences

NARCIS (Netherlands)

Beyers, J.; Hanegraaff, M.

The growing attempts by non-state interests to influence global policy processes has attracted much scholarly interest in recent years. One important question thereby is what characterizes and explains the interactions of non-state advocates with policymakers. In order to clarify this matter, we

Explaining sex differences in chronic musculoskeletal pain in a general population.

NARCIS (Netherlands)

Wijnhoven, Hanneke A H; Vet, Henrica C W de; Picavet, H Susan J

2006-01-01

Many studies report a female predominance in the prevalence of chronic musculoskeletal pain (CMP) but the mechanisms explaining these sex differences are poorly understood. Data from a random postal questionnaire survey in the Dutch general population were used to examine whether sex differences in

Explaining Career Decision-Making Self-Efficacy: Personality, Cognitions, and Cultural Mistrust

Science.gov (United States)

Bullock-Yowell, Emily; Andrews, Lindsay; Buzzetta, Mary E.

2011-01-01

The authors explore the hypothesis that career decision-making self-efficacy could be affected by negative career thoughts, Big Five personality factors, and cultural mistrust in a sample of African American and Caucasian college students. Findings demonstrated that negative career thinking, openness, and conscientiousness explained a significant…

Comparative distribution of the fan mussel Atrina fragilis (Bivalvia, Pinnidae in protected and trawled areas of the north Aegean Sea (Thermaikos Gulf

Directory of Open Access Journals (Sweden)

K. FRYGANIOTIS

2013-02-01

Full Text Available The distribution of the fan mussel Atrina fragilis was studied at two contrasting areas of the north Aegean Sea (Thermaikos Gulf: one routinely trawled and one closed to trawlers for over 25 years. Significant differences were detected between the two areas with decreased values in density and size of A. fragilis individuals at the trawled area. As habitat differences, i.e. sediment composition and bathymetry, had non-significant effect, extensive trawling activities probably explain the observed results.

Benthic macroinvertebrates as bioindicators of water quality in an Atlantic forest fragment

Directory of Open Access Journals (Sweden)

Augusto Oliveira

2010-12-01

Full Text Available The objective of this study was to evaluate benthic macroinvertebrate communities as bioindicators of water quality in five streams located in the "Reserva Particular do Patrimônio Natural" (RPPN Mata Samuel de Paula and its surroundings, in the municipality of Nova Lima near the city of Belo Horizonte, Minas Gerais State, southeastern Brazil. This region has been strongly modified by human activities including mining and urbanization. Samples were collected in the field every three months between August 2004 and November 2005, totaling six samplings in the rainy and dry seasons. This assessment identified one area ecologically altered while the other sampling sites were found to be minimally disturbed systems, with well-preserved ecological conditions. However, according to the Biological Monitoring Work Party (BMWP and the Average Score Per Taxon (ASPT indices, all sampling sites had excellent water quality. A total of 14,952 organisms was collected, belonging to 155 taxa (148 Insecta, two Annelida, one Bivalvia, one Decapoda, one Planariidae, one Hydracarina, and one Entognatha. The most abundant benthic groups were Chironomidae (47.9%, Simuliidae (12.3%, Bivalvia (7.5%, Decapoda (6.1%, Oligochaeta (5.2%, Polycentropodidae (3.7%, Hydropsychidae (2.5%, Calamoceratidae (1.8%, Ceratopogonidae (1.7%, and Libellulidae (1.2%. The assessment of the benthic functional feeding groups showed that 34% of the macroinvertebrates were collector-gatherers, 29% predators, 24% collector-filterers, 8% shredders, and 5% scrapers. The RPPN Mata Samuel de Paula comprises diversified freshwater habitats that are of great importance for the conservation of many benthic taxa that are intolerant to organic pollution.

Explaining How to Play Real-Time Strategy Games

Science.gov (United States)

Metoyer, Ronald; Stumpf, Simone; Neumann, Christoph; Dodge, Jonathan; Cao, Jill; Schnabel, Aaron

Real-time strategy games share many aspects with real situations in domains such as battle planning, air traffic control, and emergency response team management which makes them appealing test-beds for Artificial Intelligence (AI) and machine learning. End user annotations could help to provide supplemental information for learning algorithms, especially when training data is sparse. This paper presents a formative study to uncover how experienced users explain game play in real-time strategy games. We report the results of our analysis of explanations and discuss their characteristics that could support the design of systems for use by experienced real-time strategy game users in specifying or annotating strategy-oriented behavior.

Possibility to explain the temperature distribution in sunspots by an anisotropic heat transfer

Energy Technology Data Exchange (ETDEWEB)

Eschrich, K O; Krause, F [Akademie der Wissenschaften der DDR, Potsdam. Zentralinstitut fuer Astrophysik

1977-01-01

Numerical solutions of a heat conduction problem in an anisotropic medium are used for a discussion of the possibility to explain the temperature distribution in sunspots and their environment. The anisotropy is assumed being due to the strong magnetic field in sunspots and the region below. This magnetic field forces the convection to take an anisotropic structure (two-dimensional turbulence) and thus the region gets anisotropic conduction properties, on the average. The discussion shows that the observed temperature profiles can be explained in the case the depth of the region of anisotropy is about as large as the diameter of the spot or larger.

Trophic niche and habitat shifts of sympatric Gerreidae.

Science.gov (United States)

Ramos, J A A; Barletta, M; Dantas, D V; Lima, A R A; Costa, M F

2014-11-01

The diet and mouth growth rates of three Gerreidae species (Eugerres brasilianus, Eucinostomus melanopterus and Diapterus rhombeus) were assessed at different ontogenetic phases (juveniles, sub-adults and adults) in order to detect allometric growth, and whether they are related to habitat and seasonal changes in the Goiana Estuary, north-east Brazil. The importance of each prey for each ontogenetic phase was described using the index of relative importance. The three species showed seasonal ontogenetic shifts in diet and allometric growth of mouth morphology. They also had an exclusively zoobenthic diet, comprising mainly Polychaeta, Copepoda, Ostracoda, Gastropoda and Bivalvia. Mouth development showed a possible influence on diet changes for E. melanopterus. Significant interactions (P < 0·01) were detected among seasons, areas and ontogenetic phases for the most important prey for E. brasilianus and E. melanopterus. Diet overlaps are evidence of intra and interspecific competition among gerreids for specific prey. A conceptual model of the competition and seasonal diet shifts among ontogenetic phases of gerreids is given. The sediment ingested due to the feeding mechanisms of Gerreidae species could also partially explain the ingestion of synthetic items observed for all ontogenetic phases, which indicates one of a myriad effects of human activities (e.g. artisanal fishery) in this estuary. © 2014 The Fisheries Society of the British Isles.

A simple model explaining super-resolution in absolute optical instruments

Science.gov (United States)

Leonhardt, Ulf; Sahebdivan, Sahar; Kogan, Alex; Tyc, Tomáš

2015-05-01

We develop a simple, one-dimensional model for super-resolution in absolute optical instruments that is able to describe the interplay between sources and detectors. Our model explains the subwavelength sensitivity of a point detector to a point source reported in previous computer simulations and experiments (Miñano 2011 New J. Phys.13 125009; Miñano 2014 New J. Phys.16 033015).

Explaining excess morbidity amongst homeless shelter users

DEFF Research Database (Denmark)

Benjaminsen, Lars; Birkelund, Jesper Fels

2018-01-01

AIMS: This article analyses excess morbidity amongst homeless shelter users compared to the general Danish population. The study provides an extensive control for confounding and investigates to what extent excess morbidity is explained by homelessness or other risk factors. METHODS: Data set...... includes administrative micro-data for 4,068,926 Danes who were 23 years or older on 1 January 2007. Nationwide data on shelter use identified 14,730 individuals as shelter users from 2002 to 2006. Somatic diseases were measured from 2007 to 2011 through diagnosis data from hospital discharges. The risk...... of somatic diseases amongst shelter users was analysed through a multivariate model that decomposed the total effect into a direct effect and indirect effects mediated by other risk factors. RESULTS: The excess morbidity associated with shelter use is substantially lower than in studies that did not include...

The Role of Colorism in Explaining African American Females' Suspension Risk

Science.gov (United States)

Blake, Jamilia J.; Keith, Verna M.; Luo, Wen; Le, Huong; Salter, Phia

2017-01-01

African American female students' elevated suspension risk has received national attention. Despite a number of studies documenting racial/ethnic disparities in African American females' school suspension risk, few investigations have attempted to explain why these disparities occur. The purpose of this study was to examine the role of colorism in…

Time delay and noise explaining the behaviour of the cell growth in fermentation process

Energy Technology Data Exchange (ETDEWEB)

Ayuobi, Tawfiqullah; Rosli, Norhayati [Faculty of Industrial Sciences and Technology, Universiti Malaysia Pahang, Lebuhraya Tun Razak, 26300 Gambang, Pahang (Malaysia); Bahar, Arifah [Department of Mathematical Sciences, Faculty of Science, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Salleh, Madihah Md [Department of Biotechnology Industry, Faculty of Biosciences and Bioengineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia)

2015-02-03

This paper proposes to investigate the interplay between time delay and external noise in explaining the behaviour of the microbial growth in batch fermentation process. Time delay and noise are modelled jointly via stochastic delay differential equations (SDDEs). The typical behaviour of cell concentration in batch fermentation process under this model is investigated. Milstein scheme is applied for solving this model numerically. Simulation results illustrate the effects of time delay and external noise in explaining the lag and stationary phases, respectively for the cell growth of fermentation process.

Time delay and noise explaining the behaviour of the cell growth in fermentation process

Science.gov (United States)

Ayuobi, Tawfiqullah; Rosli, Norhayati; Bahar, Arifah; Salleh, Madihah Md

2015-02-01

This paper proposes to investigate the interplay between time delay and external noise in explaining the behaviour of the microbial growth in batch fermentation process. Time delay and noise are modelled jointly via stochastic delay differential equations (SDDEs). The typical behaviour of cell concentration in batch fermentation process under this model is investigated. Milstein scheme is applied for solving this model numerically. Simulation results illustrate the effects of time delay and external noise in explaining the lag and stationary phases, respectively for the cell growth of fermentation process.

Time delay and noise explaining the behaviour of the cell growth in fermentation process

International Nuclear Information System (INIS)

Ayuobi, Tawfiqullah; Rosli, Norhayati; Bahar, Arifah; Salleh, Madihah Md

2015-01-01

This paper proposes to investigate the interplay between time delay and external noise in explaining the behaviour of the microbial growth in batch fermentation process. Time delay and noise are modelled jointly via stochastic delay differential equations (SDDEs). The typical behaviour of cell concentration in batch fermentation process under this model is investigated. Milstein scheme is applied for solving this model numerically. Simulation results illustrate the effects of time delay and external noise in explaining the lag and stationary phases, respectively for the cell growth of fermentation process

Explaining inequalities in women's mortality between U.S. States

Directory of Open Access Journals (Sweden)

Jennifer Karas Montez

2016-12-01

Full Text Available Inequalities in women's mortality between U.S. states are large and growing. It is unknown whether they reflect differences between states in their population characteristics, contextual characteristics, or both. This study systematically examines the large inequalities in women's mortality between U.S. states using a multilevel approach. It focuses on “fundamental” social determinants of mortality at the individual and state levels as potential explanations. We analyze data from the 2013 public-use National Longitudinal Mortality Study on women aged 45–89 years and estimate multilevel logistic regression models. The models include women's personal characteristics (age, race/ethnicity, education, employment, income, and marriage and states’ contextual characteristics (economic environment, social cohesion, sociopolitical orientation, physical infrastructure, and tobacco environment. We found that variation in women's mortality across states was significant (p<0.001. Adjusting for women's personal characteristics explained 30% of the variation. Additionally adjusting for states’ contextual characteristics explained 62% of the variation; the most important characteristics were social cohesion and economic conditions. No significant mortality differences between any two states remained after accounting for individual and contextual characteristics. Supplementary analyses of men indicate that state contexts have stronger and more pernicious consequences for women than men. Taken together, the findings underscore the importance of ‘bringing context back in’ and taking a multilevel approach when investigating geographic inequalities in U.S. mortality. Keywords: Mortality, Gender, Inequality, Social determinants, U.S. states, Multilevel

Explaining the differential distribution of Clean Development Mechanism projects across host countries

International Nuclear Information System (INIS)

Winkelman, Andrew G.; Moore, Michael R.

2011-01-01

The Clean Development Mechanism (CDM) of the Kyoto Protocol represents an opportunity to involve all developing countries in the effort to reduce greenhouse gas emissions while also promoting sustainable development. To date, however, the majority of CDM projects have gone to emerging markets such as China, India, Brazil, and Mexico, while very few least developed countries have hosted projects. This paper investigates the differential distribution of CDM activities across countries. We develop a conceptual model for project profitability, which helps to identify potential country-level determinants of CDM activity. These potential determinants are employed as explanatory variables in regression analysis to explain the actual distribution of projects. Human capital and greenhouse gas emission levels influenced which countries have hosted projects and the amount of certified emission reductions (CER) created. Countries that offered growing markets for CDM co-products, such as electricity, were more likely to be CDM hosts, while economies with higher carbon intensity levels had greater CER production. These findings work against the least developed countries and help to explain their lack of CDM activity. - Research Highlights: → Regression models are used to explain the inter-country distribution of CDM projects. → Emissions and human capital are significant for hosting projects and CER creation. → An economy's emissions intensity is significant in determining CERs created. → Capacity building and electricity sector growth are significant in hosting projects. → The experience level for host countries in the CDM is significant for CER creation.

Explaining consumer attitudes to genetic modification in food production

DEFF Research Database (Denmark)

Bredahl, Lone

for explaining consumer attitudes to genetic modification in food production which builds on modern cognitive psychology and multi-attribute attitude theory. In addition, the paper introduces the empirical research which is undertaken at present to validate and estimate the parameters of the model by means......Consumers have not had many possibilities yet for seeking out, buying and consuming genetically modified food products. However, for various reasons consumer attitude formation with regard to these products is likely to be complex and closely related to personal values. The paper presents a model...

Explaining the so-called 'price premium' in oil markets

International Nuclear Information System (INIS)

Merino, A.; Ortiz, A.

2005-01-01

This paper explores the information content of several variables on the so-called ''oil price premium over fundamentals''. We define this premium as the difference between the market oil price and the estimated price consistent with the OECD's relative industry stock level. By using Granger causality tests and extended regressions we test the systematic ability of a broad set of variables to explain the premium. We find that speculation in the oil market - measured by non-commercial long positions - can improve the traditional model, reducing the premium significantly during some parts of the sample. (author)

Is Wagner’s theory relevant in explaining health expenditure dynamics in Botswana?

Directory of Open Access Journals (Sweden)

Kunofiwa Tsaurai

2014-11-01

Full Text Available This study tests the relevance of the Wagner’s theory in explaining the health expenditure in Botswana. There is no consensus yet when it comes to the causality relationship between health expenditure and economy. At the moment, there are four dominant schools of thought explaining the causality relationship between health expenditure and economy. The first school of thought is that health expenditure spurs the economy whilst the second school of thought says that the economy drives health expenditure. The third school of thought maintains that there is a feedback effect between health expenditure and the economy whilst the fourth mentions that there is no causality at all between the two variables. However, this study found out that there is no causality relationship between health expenditure and GDP in Botswana thereby dismissing the relevance of the Wagner’s theory.

Furcocercous cercariae (Trematoda) from freshwater snails in Central Finland

Czech Academy of Sciences Publication Activity Database

Faltýnková, Anna; Niewiadomska, K.; Santos, M. J.; Valtonen, E. T.

2007-01-01

Roč. 52, č. 4 (2007), s. 310-317 ISSN 1230-2821 R&D Projects: GA AV ČR IAA6022404; GA ČR GP524/07/P086; GA ČR GD524/03/H133; GA MŠk LC522 Grant - others: Portuguese FCT(PT) SFRH/BSAB/492/2005 Institutional research plan: CEZ:AV0Z60220518 Keywords : cercariae * Mollusca * Finland * Trematoda * Pulmonata * Prosobranchia * Valvata macrostoma Subject RIV: EG - Zoology Impact factor: 0.814, year: 2007

Water Quality Criteria for Colored Smokes: Solvent Yellow 33

Science.gov (United States)

1987-11-01

Wr e. a benthic crustacean (e.g, ostracod, isopod, or amphipod): f. an insect (e.g., mayfly, midge, stonefly)- g. a family in a phylum other than...Arthropoda or Chordata (e.g, Annelida or Mollusca): and h, a family in any order of insect or any phylum not represented. 2. Acute-chronic ratios (see...acute toxicity to freshwater acuatic animals should be used: a. Tests with daphnids and other cladocerans should be started with organisms < 24 hr old

Patterns of larval distribution and settlement of Concholepas concholepas (Bruguiere, 1789) (Gastropoda, Muricidae) in fjords and channels of southern Chile

OpenAIRE

MOLINET, CARLOS; ARÉVALO, ALEJANDRA; GONZÁLEZ, MARÍA TERESA; MORENO, CARLOS A.; ARATA, JAVIER; NIKLITSCHEK, EDWIN

2005-01-01

The distribution of Concholepas concholepas (Mollusca, Gastropoda, Muricidae) is limited to the coasts of Chile and southern Peru. Almost all studies of this gastropod have been carried out in open coastal systems, rather than the fjords and channels of southern Chile, despite the fact that this area represents ca. 95 % of the total coastline in this country. Although there is a large volume of background literature on C. concholepas, almost nothing is published about early larval development...

Patterns of larval distribution and settlement of Concholepas concholepas (Bruguiere, 1789) (Gastropoda, Muricidae) in fjords and channels of southern Chile Patrones de distribución de larvas y asentamiento de Concholepas concholepas (Bruguiere, 1789) (Gastropoda, Muricidae) en fiordos y canales del sur de Chile

OpenAIRE

CARLOS MOLINET; ALEJANDRA ARÉVALO; MARÍA TERESA GONZÁLEZ; CARLOS A. MORENO; JAVIER ARATA; EDWIN NIKLITSCHEK

2005-01-01

The distribution of Concholepas concholepas (Mollusca, Gastropoda, Muricidae) is limited to the coasts of Chile and southern Peru. Almost all studies of this gastropod have been carried out in open coastal systems, rather than the fjords and channels of southern Chile, despite the fact that this area represents ca. 95 % of the total coastline in this country. Although there is a large volume of background literature on C. concholepas, almost nothing is published about early larval development...

SELECTIVIDAD DEL INSECTICIDA CARTAP EMPLEANDO BIOENSAYOS CON ORGANISMOS NO DESTINATARIOS

OpenAIRE

Iannacone, José; Universidad Nacional Federico Villarreal (Perú).; Alvariño, Lorena; Universidad Nacional Federico Villarreal (Perú).

2016-01-01

El objetivo de la presente investigación fue evaluar la ecotoxicidad del cartap (Bala® 50 PS) sobre ocho organismos animales no destinatarios: 1) Melanoides tuberculata (Müller, 1774) (Mollusca), 2) Emerita analoga (Stimpson, 1857) (Crustácea), 3) Chironomus calligraphus Goeldi, 1805 (Diptera), 4) Cyprinus carpio (Linné, 1758) (Osteichyties), 5) Eisenia foetida (Savigny, 1826) (Annelida), 6) Podisus nigrispinus (Dallas, 1851) (Hemiptera), 7) Trichogramma fuentesi Torre, 1980 (Hymenoptera) y 8...

Coal liquefaction policy in China: Explaining the policy reversal since 2006

International Nuclear Information System (INIS)

Rong Fang; Victor, David G.

2011-01-01

China has emerged as a leader in coal liquefaction. While the country's abundant coal resources and acute concerns about oil security help explain China's interest in liquefaction, the driving forces for this industry are complicated and policy has been inconsistent. Since 2006 Beijing has tried to slow down the development of liquefaction; even as China has become more dependent on imported oil, the central government has been wary about the large impact of liquefaction technologies on scarce resources such as water. However, local government officials in coal rich areas have strong incentives to pour investment into the technology, which helps explain the uneven development and policy. The future of coal liquefaction will depend on how these forces unfold along with major Beijing-led reforms in the Chinese coal industry, which is closing smaller mines and favoring the emergence of larger coal producing firms. Those reforms will have mixed effects on liquefaction. They temporarily contribute to higher prices for coal while over the longer term creating coal companies that have much greater financial and technical skills needed to deploy technologies such as coal liquefaction at a scale needed if this energy pathway is to be competitive with conventional sources of liquid fuel. - Highlights: ► We explain swings in Chinese policy on coal liquefaction, a possible substitute for imported oil. ► Since 2006 Beijing's support has waned due to fears about environmental impacts and cost of liquefaction. ► Local governments in some coal rich regions remain strongly supportive. ► Volatile oil prices and rising coal prices make this industry more risky than previously thought. ► Consolidation of the coal industry will have mixed effects on viability of liquefaction projects.

White matter tract network disruption explains reduced conscientiousness in multiple sclerosis.

Science.gov (United States)

Fuchs, Tom A; Dwyer, Michael G; Kuceyeski, Amy; Choudhery, Sanjeevani; Carolus, Keith; Li, Xian; Mallory, Matthew; Weinstock-Guttman, Bianca; Jakimovski, Dejan; Ramasamy, Deepa; Zivadinov, Robert; Benedict, Ralph H B

2018-05-08

Quantifying white matter (WM) tract disruption in people with multiple sclerosis (PwMS) provides a novel means for investigating the relationship between defective network connectivity and clinical markers. PwMS exhibit perturbations in personality, where decreased Conscientiousness is particularly prominent. This trait deficit influences disease trajectory and functional outcomes such as work capacity. We aimed to identify patterns of WM tract disruption related to decreased Conscientiousness in PwMS. Personality assessment and brain MRI were obtained in 133 PwMS and 49 age- and sex-matched healthy controls (HC). Lesion maps were applied to determine the severity of WM tract disruption between pairs of gray matter regions. Next, the Network-Based-Statistics tool was applied to identify structural networks whose disruption negatively correlates with Conscientiousness. Finally, to determine whether these networks explain unique variance above conventional MRI measures and cognition, regression models were applied controlling for age, sex, brain volume, T2-lesion volume, and cognition. Relative to HCs, PwMS exhibited lower Conscientiousness and slowed cognitive processing speed (p = .025, p = .006). Lower Conscientiousness in PwMS was significantly associated with WM tract disruption between frontal, frontal-parietal, and frontal-cingulate pathways in the left (p = .02) and right (p = .01) hemisphere. The mean disruption of these pathways explained unique additive variance in Conscientiousness, after accounting for conventional MRI markers of pathology and cognition (ΔR 2  = .049, p = .029). Damage to WM tracts between frontal, frontal-parietal, and frontal-cingulate cortical regions is significantly correlated with reduced Conscientiousness in PwMS. Tract disruption within these networks explains decreased Conscientiousness observed in PwMS as compared with HCs. © 2018 Wiley Periodicals, Inc.

Explaining fast radio bursts through Dicke's superradiance

Science.gov (United States)

Houde, Martin; Mathews, Abhilash; Rajabi, Fereshteh

2018-03-01

Fast radio bursts (FRBs), characterized by strong bursts of radiation intensity at radio wavelengths lasting on the order of a millisecond, have yet to be firmly associated with a family, or families, of astronomical sources. It follows that despite the large number of proposed models, no well-defined physical process has been identified to explain this phenomenon. In this paper, we demonstrate how Dicke's superradiance, for which evidence has recently been found in the interstellar medium, can account for the characteristics associated with FRBs. Our analysis and modelling of previously detected FRBs suggest they could originate from regions in many ways similar to those known to harbour masers or megamasers, and result from the coherent radiation emanating from populations of molecules associated with large-scale entangled quantum mechanical states. We estimate this entanglement to involve as many as ˜1030 to ˜1032 molecules over distances spanning 100-1000 au.

Testing and Explaining Differences in Common and Residual Factors Across Many Countries

NARCIS (Netherlands)

Jak, S.

2017-01-01

To make valid comparisons across countries, a measurement instrument needs to be measurement invariant across countries. The present article provides a nontechnical exposition of a recently proposed multilevel factor analysis approach to test measurement invariance across countries. It is explained

Nutrient analysis explained for non-chemists by using interactive e-learning material

NARCIS (Netherlands)

Busstra, M.C.; Hulshof, P.J.M.; Houwen, J.; Elburg, L.; Hollman, P.C.H.

2012-01-01

The diverse educational and professional background of individuals involved in food composition data work presents challenges in their training. In particular, it is difficult to explain chemical analysis of nutrients to individuals lacking a background in chemistry. Therefore an interactive

What Explains the Survival Gap of Pushed and Pulled Corporate Spin-offs?

DEFF Research Database (Denmark)

Rocha, Vera; Carneiro, Anabela; Varum, Celeste

2015-01-01

Unconditionally, pushed spin-offs are found to survive longer than their pulled counterparts. Using matched employer-employee data and novel multivariate decomposition techniques, we show that pushed spin-offs’ relative survival advantage is mostly explained by their larger human capital endowments...

How Much Is Enough? Explaining the Continuous Transparency Conflict in TTIP

Directory of Open Access Journals (Sweden)

Niels Gheyle

2017-09-01

Full Text Available Transparency has been a central issue in the debate regarding the Transatlantic Trade and Investment Partnership (TTIP, especially on the side of the European Union (EU. The lack of transparency in the negotiating process has been one of the main criticisms of civil society organizations (CSOs. The European Commission (EC has tried to gain support for the negotiations through various ‘transparency initiatives’. Nonetheless, criticism by CSOs with regard to TTIP in general and the lack of transparency in specific remained prevalent. In this article, we explain this gap between various transparency initiatives implemented by the EC in TTIP and the expectations on the side of European CSOs. We perform a content analysis of position papers on transparency produced by CSOs, mainly in response to a European Ombudsman consultation, complemented by a number of official documents and targeted interviews. We find that the gap between the TTIP transparency initiatives and the expectations of CSOs can be explained by different views on what constitutes legitimate trade governance, and the role of transparency, participation, and accountability herein.

Explaining the relationship between religiousness and substance use: self-control matters.

Science.gov (United States)

DeWall, C Nathan; Pond, Richard S; Carter, Evan C; McCullough, Michael E; Lambert, Nathaniel M; Fincham, Frank D; Nezlek, John B

2014-08-01

Religiousness is reliably associated with lower substance use, but little research has examined whether self-control helps explain why religiousness predicts lower substance use. Building on prior theoretical work, our studies suggest that self-control mediates the relationship between religiousness and a variety of substance-use behaviors. Study 1 showed that daily prayer predicted lower alcohol use on subsequent days. In Study 2, religiousness related to lower alcohol use, which was mediated by self-control. Study 3 replicated this mediational pattern using a behavioral measure of self-control. Using a longitudinal design, Study 4 revealed that self-control mediated the relationship between religiousness and lower alcohol use 6 weeks later. Study 5 replicated this mediational pattern again and showed that it remained significant after controlling for trait mindfulness. Studies 6 and 7 replicated and extended these effects to both alcohol and various forms of drug use among community and cross-cultural adult samples. These findings offer novel evidence regarding the role of self-control in explaining why religiousness is associated with lower substance use.

Selective Pressures Explain Differences in Flower Color among Gentiana lutea Populations.

Science.gov (United States)

Sobral, Mar; Veiga, Tania; Domínguez, Paula; Guitián, Javier A; Guitián, Pablo; Guitián, José M

2015-01-01

Flower color variation among plant populations might reflect adaptation to local conditions such as the interacting animal community. In the northwest Iberian Peninsula, flower color of Gentiana lutea varies longitudinally among populations, ranging from orange to yellow. We explored whether flower color is locally adapted and the role of pollinators and seed predators as agents of selection by analyzing the influence of flower color on (i) pollinator visitation rate and (ii) escape from seed predation and (iii) by testing whether differences in pollinator communities correlate with flower color variation across populations. Finally, (iv) we investigated whether variation in selective pressures explains flower color variation among 12 G. lutea populations. Flower color influenced pollinator visits and differences in flower color among populations were related to variation in pollinator communities. Selective pressures on flower color vary among populations and explain part of flower color differences among populations of G. lutea. We conclude that flower color in G. lutea is locally adapted and that pollinators play a role in this adaptation.

Selective Pressures Explain Differences in Flower Color among Gentiana lutea Populations.

Directory of Open Access Journals (Sweden)

Mar Sobral

Full Text Available Flower color variation among plant populations might reflect adaptation to local conditions such as the interacting animal community. In the northwest Iberian Peninsula, flower color of Gentiana lutea varies longitudinally among populations, ranging from orange to yellow. We explored whether flower color is locally adapted and the role of pollinators and seed predators as agents of selection by analyzing the influence of flower color on (i pollinator visitation rate and (ii escape from seed predation and (iii by testing whether differences in pollinator communities correlate with flower color variation across populations. Finally, (iv we investigated whether variation in selective pressures explains flower color variation among 12 G. lutea populations. Flower color influenced pollinator visits and differences in flower color among populations were related to variation in pollinator communities. Selective pressures on flower color vary among populations and explain part of flower color differences among populations of G. lutea. We conclude that flower color in G. lutea is locally adapted and that pollinators play a role in this adaptation.

A case-mix classification system for explaining healthcare costs using administrative data in Italy.

Science.gov (United States)

Corti, Maria Chiara; Avossa, Francesco; Schievano, Elena; Gallina, Pietro; Ferroni, Eliana; Alba, Natalia; Dotto, Matilde; Basso, Cristina; Netti, Silvia Tiozzo; Fedeli, Ugo; Mantoan, Domenico

2018-03-04

The Italian National Health Service (NHS) provides universal coverage to all citizens, granting primary and hospital care with a copayment system for outpatient and drug services. Financing of Local Health Trusts (LHTs) is based on a capitation system adjusted only for age, gender and area of residence. We applied a risk-adjustment system (Johns Hopkins Adjusted Clinical Groups System, ACG® System) in order to explain health care costs using routinely collected administrative data in the Veneto Region (North-eastern Italy). All residents in the Veneto Region were included in the study. The ACG system was applied to classify the regional population based on the following information sources for the year 2015: Hospital Discharges, Emergency Room visits, Chronic disease registry for copayment exemptions, ambulatory visits, medications, the Home care database, and drug prescriptions. Simple linear regressions were used to contrast an age-gender model to models incorporating more comprehensive risk measures aimed at predicting health care costs. A simple age-gender model explained only 8% of the variance of 2015 total costs. Adding diagnoses-related variables provided a 23% increase, while pharmacy based variables provided an additional 17% increase in explained variance. The adjusted R-squared of the comprehensive model was 6 times that of the simple age-gender model. ACG System provides substantial improvement in predicting health care costs when compared to simple age-gender adjustments. Aging itself is not the main determinant of the increase of health care costs, which is better explained by the accumulation of chronic conditions and the resulting multimorbidity. Copyright © 2018. Published by Elsevier B.V.

What Is Sexual Orientation All About? Explaining an Evolutionary Paradox

OpenAIRE

Brad Bowins

2015-01-01

Numerous psychological, biological, and evolutionary theories have been proposed to explain sexual orientation. For a theory to be valid it must account for the evolutionary or Darwinian paradox of how homosexual behavior seemingly blocking evolutionary fitness could have evolved. Typically it is only evolutionary based theories that attempt to address this issue. All theories proposed to date have limitations, a major one being that they tend to be specific for male or female sexual orientat...

Discovering and explaining work-family strategies of parents in Luxembourg

OpenAIRE

Zhelyazkova, Nevena

2014-01-01

The presented analysis discovers and explains typical patterns of work-family reconciliation for parents who had a child in the same period (2003) and in the same country (Luxembourg), thus facing the same macroeconomic and institutional conditions. Work-family trajectories are reconstructed as sequences of states using administrative records, so that working hours and use of leave provisions or other social security benefits are taken into account. Next, a clustering algorithm is applied to ...

Glacial ocean circulation and stratification explained by reduced atmospheric temperature

OpenAIRE

Jansen, Malte F.

2016-01-01

To understand climatic swings between glacial and interglacial climates we need to explain the observed fluctuations in atmospheric carbon dioxide (CO2), which in turn are most likely driven by changes in the deep ocean circulation. This study presents a model for differences in the deep ocean circulation between glacial and interglacial climates consistent with both our physical understanding and various proxy observations. The results suggest that observed changes in ocean circulation and s...

Variações no comprimento dos indivíduos de uma população do mexilhão dourado, Limnoperna fortunei (Mollusca: Bivalvia: Mytilidae, ao longo do ano, na Praia do Veludo, Lago Guaíba, Rio Grande do Sul, Brasil Length variation over a one-year period in specimens of the golden mussel, Limnoperna fortunei (Mollusca: Bivalvia: Mytilidae from Veludo Beach, Guaíba Lake, Rio Grande do Sul, Brazil

Directory of Open Access Journals (Sweden)

Cintia P. dos Santos

2008-09-01

Full Text Available The individual size of Limnoperna fortunei (Dunker, 1857 was evaluated twice a month, for a year, based on samples from Veludo Beach (30º12'35"S, 51º11'68"W in Guaiba Lake, southern Porto Alegre, Brazil. Physical and chemical data on water quality, such as temperature, transparency, depth, pH, dissolved oxygen, phosphorus, nitrogen, chlorophyll "a", and conductivity were also recorded. Adult samples were collected from underwater "sarandi" branches, Cephalanthus glabratus (Spreng K. Schum (Rubiaceae, an aquatic macrophyte available at each site. Adults placed on artificial substrates were also checked every six months. Data were analyzed by applying multivariate statistics techniques related to the physical and chemical variables of the water and the density of individuals to estimate the patterns of the individual growth over the year. The adults were separated into three groups according to length classes: G1, G2 and G3 (groups 1 through 3. These three groups are related to the differences in behavior, namely, the ability of locomotion and fixation capacity. Individuals from Group 1 (5 to 7 mm in length were the most abundant and were present in all the sampled months. Adults from artificial substrates were shown to display significant differences in seasonal growth and faster growth during spring and summer months.

Short Communication Myosotella myosotis (Mollusca: Ellobiidae ...

African Journals Online (AJOL)

Myosotella myosotis is shown to be a well-established alien species in South Africa. Discovered in Port Elizabeth more than 100 years ago, it was initially thought to be indigenous and was described under two different names, but subsequent taxonomic work has demonstrated that these are synonyms of the variable and ...

Do the SuperKamiokande atmospheric neutrino results explain electric charge quantisation?

International Nuclear Information System (INIS)

Foot, R.; Volkas, R.R.

1998-08-01

It is shown that the SuperKamiokande atmospheric neutrino results explain electric charge quantisation, provided that the oscillation mode is ν μ → ν τ and that the neutrino mass is of the Majorana type. It is emphasised that neutrino oscillation and neutrinoless double beta decay experiments provide important information regarding the seemingly unrelated issue of electric charge quantisation

Beyond dichotomous explanations: Explaining constitutional control of the executieve with fuzzy-sets.

NARCIS (Netherlands)

Pennings, P.J.M.

2003-01-01

What are the main variations in the constitutional control of the executive in 45 parliamentary democracies and how can these differences be accounted for? Four competing hypotheses, based on dichotomies, explain the degree of this control by means of contrasting institutional settings: consensus

Beyond dichotomous explanations: explaining constitutional control of the executive with fuzzy-sets

NARCIS (Netherlands)

Pennings, P.J.M.

2003-01-01

What are the main variations in the constitutional control of the executive in 45 parliamentary democracies and how can these differences be accounted for? Four competing hypotheses, based on dichotomies, explain the degree of this control by means of contrasting institutional settings: consensus

Depressive status explains a significant amount of the variance in COPD assessment test (CAT) scores.

Science.gov (United States)

Miravitlles, Marc; Molina, Jesús; Quintano, José Antonio; Campuzano, Anna; Pérez, Joselín; Roncero, Carlos

2018-01-01

COPD assessment test (CAT) is a short, easy-to-complete health status tool that has been incorporated into the multidimensional assessment of COPD in order to guide therapy; therefore, it is important to understand the factors determining CAT scores. This is a post hoc analysis of a cross-sectional, observational study conducted in respiratory medicine departments and primary care centers in Spain with the aim of identifying the factors determining CAT scores, focusing particularly on the cognitive status measured by the Mini-Mental State Examination (MMSE) and levels of depression measured by the short Beck Depression Inventory (BDI). A total of 684 COPD patients were analyzed; 84.1% were men, the mean age of patients was 68.7 years, and the mean forced expiratory volume in 1 second (%) was 55.1%. Mean CAT score was 21.8. CAT scores correlated with the MMSE score (Pearson's coefficient r =-0.371) and the BDI ( r =0.620), both p CAT scores and explained 45% of the variability. However, a model including only MMSE and BDI scores explained up to 40% and BDI alone explained 38% of the CAT variance. CAT scores are associated with clinical variables of severity of COPD. However, cognitive status and, in particular, the level of depression explain a larger percentage of the variance in the CAT scores than the usual COPD clinical severity variables.

Explaining the Higgs decays at the LHC with an extended electroweak model

International Nuclear Information System (INIS)

Alves, Alexandre; Ramirez Barreto, E.; Dias, A.G.; Pires, S.C.A. de; Rodrigues da Silva, P.S.; Queiroz, Farinaldo S.

2013-01-01

We show that the observed enhancement in the diphoton decays of the recently discovered new boson at the LHC, which we assume to be a Higgs boson, can be naturally explained by a new doublet of charged vector bosons from extended electroweak models with SU(3) C x SU(3) L x U(1) X symmetry. These models are also rather economical in explaining the measured signal strengths, within the current experimental errors, demanding fewer assumptions and less parameters tuning. Our results show a good agreement between the theoretical expected sensitivity to a 126-125 GeV Higgs boson, and the experimental significance observed in the diphoton channel at the 8 TeV LHC. Effects of an invisible decay channel for the Higgs boson are also taken into account, in order to anticipate a possible confirmation of deficits in the branching ratios into ZZ * , WW * , bottom quarks, and tau leptons. (orig.)

Mutations in the VEGFR3 signaling pathway explain 36% of familial lymphedema

DEFF Research Database (Denmark)

Mendola, A; Schlögel, M J; Ghalamkarpour, A

2013-01-01

Lymphedema is caused by dysfunction of lymphatic vessels, leading to disabling swelling that occurs mostly on the extremities. Lymphedema can be either primary (congenital) or secondary (acquired). Familial primary lymphedema commonly segregates in an autosomal dominant or recessive manner. It can...... of these putative genes. We screened 78 index patients from families with inherited lymphedema for mutations in FLT4, GJC2, FOXC2, SOX18, GATA2, CCBE1, and PTPN14. Altogether, we discovered 28 mutations explaining 36% of the cases. Additionally, 149 patients with sporadic primary lymphedema were screened for FLT4......, FOXC2, SOX18, CCBE1, and PTPN14. Twelve mutations were found that explain 8% of the cases. Still unidentified is the genetic cause of primary lymphedema in 64% of patients with a family history and 92% of sporadic cases. Identification of those genes is important for understanding of etiopathogenesis...

The variance of the locally measured Hubble parameter explained with different estimators

DEFF Research Database (Denmark)

Odderskov, Io Sandberg Hess; Hannestad, Steen; Brandbyge, Jacob

2017-01-01

We study the expected variance of measurements of the Hubble constant, H0, as calculated in either linear perturbation theory or using non-linear velocity power spectra derived from N-body simulations. We compare the variance with that obtained by carrying out mock observations in the N......-body simulations, and show that the estimator typically used for the local Hubble constant in studies based on perturbation theory is different from the one used in studies based on N-body simulations. The latter gives larger weight to distant sources, which explains why studies based on N-body simulations tend...... to obtain a smaller variance than that found from studies based on the power spectrum. Although both approaches result in a variance too small to explain the discrepancy between the value of H0 from CMB measurements and the value measured in the local universe, these considerations are important in light...

Explaining the diversity of motivations behind community renewable energy

International Nuclear Information System (INIS)

Bauwens, Thomas

2016-01-01

Community-based renewable energy initiatives may be important actors in the transition toward low-carbon energy systems. In turn, stimulating investments in renewable energy production at the community level requires a better understanding of investors' motives. This paper aims to study the heterogeneity of motivations that drive individuals to participate in community renewable energy projects and the underlying explanatory factors behind this, as well as the implications for their level of engagement in initiatives. Based on quantitative data from an original survey conducted with two renewable energy cooperatives in Flanders, the statistical analysis shows that cooperative members should not be considered as one homogeneous group. Several categories of members with different motives and levels of engagement can be distinguished. This heterogeneity is explained by contrasts in terms of institutional settings, spatial patterns and attitudes to the diffusion of institutional innovations. Regarding policy implications, the findings suggest that this heterogeneity should be taken into account in designing more effective supporting policies to stimulate investments at the community level. The activation of social norms is also shown to be a promising mechanism for triggering investment decisions, although the implications of its interplay with economic incentives should be further explored. - Highlights: •Community-based energy projects are important actors in the low-carbon transition. •The diversity of motivations and level of engagement among members is analysed. •Several segments of members with different characteristics are distinguished. •Institutional, spatial and innovation diffusion dimensions explain this diversity. •This heterogeneity among investors should be taken into account in policy-making.

Reinforcement Learning Explains Conditional Cooperation and Its Moody Cousin.

Directory of Open Access Journals (Sweden)

Takahiro Ezaki

2016-07-01

Full Text Available Direct reciprocity, or repeated interaction, is a main mechanism to sustain cooperation under social dilemmas involving two individuals. For larger groups and networks, which are probably more relevant to understanding and engineering our society, experiments employing repeated multiplayer social dilemma games have suggested that humans often show conditional cooperation behavior and its moody variant. Mechanisms underlying these behaviors largely remain unclear. Here we provide a proximate account for this behavior by showing that individuals adopting a type of reinforcement learning, called aspiration learning, phenomenologically behave as conditional cooperator. By definition, individuals are satisfied if and only if the obtained payoff is larger than a fixed aspiration level. They reinforce actions that have resulted in satisfactory outcomes and anti-reinforce those yielding unsatisfactory outcomes. The results obtained in the present study are general in that they explain extant experimental results obtained for both so-called moody and non-moody conditional cooperation, prisoner's dilemma and public goods games, and well-mixed groups and networks. Different from the previous theory, individuals are assumed to have no access to information about what other individuals are doing such that they cannot explicitly use conditional cooperation rules. In this sense, myopic aspiration learning in which the unconditional propensity of cooperation is modulated in every discrete time step explains conditional behavior of humans. Aspiration learners showing (moody conditional cooperation obeyed a noisy GRIM-like strategy. This is different from the Pavlov, a reinforcement learning strategy promoting mutual cooperation in two-player situations.

Use of focus groups in explaining environmental risks

International Nuclear Information System (INIS)

Wong, J.W.

1994-01-01

Risk assessors need to remember their job is to determine risks which are then balanced against the cost of remediation. Since the ultimate customer is the public, they must be an integral part of both key risk assessment as well as remediation decisions. Focus groups offer a cost effective means to open-quotes get a feelclose quotes for what publics want and don't want. This paper is a kit for using focus groups to test and translate into common language, the risk assessor's ideas and methods. Explaining Monte Carlo methods for a simple aspect of ecological risk assessment is included as an example along with practical tips and a list of what the public equates to risk as they perceive it

Explaining NDVI trends in northern Burkina Faso

DEFF Research Database (Denmark)

Rasmussen, Kjeld; Fensholt, Rasmus; Fog, Bjarne

2014-01-01

by a distinct spatial pattern and strongly dominated by negative trends in Normalized Difference Vegetation Index (NDVI). The aim of the paper is to explain this distinct pattern. When studied over the period 2000–2012, using NDVI data from the MODIS sensor the spatial pattern of NDVI trends indicates that non......-climatic factors are involved. By relating NDVI trends to landscape elements and land use change we demonstrate that NDVI trends in the north-western parts of the study area are mostly related to landscape elements, while this is not the case in the south-eastern parts, where rapidly changing land use, including....... expansion of irrigation, plays a major role. It is inferred that a process of increased redistribution of fine soil material, water and vegetation from plateaus and slopes to valleys, possibly related to higher grazing pressure, may provide an explanation of the observed pattern of NDVI trends. Further work...

Explaining mutualism variation: a new evolutionary paradox?

Science.gov (United States)

Heath, Katy D; Stinchcombe, John R

2014-02-01

The paradox of mutualism is typically framed as the persistence of interspecific cooperation, despite the potential advantages of cheating. Thus, mutualism research has tended to focus on stabilizing mechanisms that prevent the invasion of low-quality partners. These mechanisms alone cannot explain the persistence of variation for partner quality observed in nature, leaving a large gap in our understanding of how mutualisms evolve. Studying partner quality variation is necessary for applying genetically explicit models to predict evolution in natural populations, a necessary step for understanding the origins of mutualisms as well as their ongoing dynamics. An evolutionary genetic approach, which is focused on naturally occurring mutualist variation, can potentially synthesize the currently disconnected fields of mutualism evolution and coevolutionary genetics. We outline explanations for the maintenance of genetic variation for mutualism and suggest approaches necessary to address them. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

Ireland and immigration: explaining the absence of the far right

OpenAIRE

Garner, Steve

2007-01-01

This article seeks to explain the absence of far-right political formations in the history of the Republic of Ireland, especially in relation to immigration. I argue that the ‘mainstream’ nationalist parties have implemented a racialized governance of Ireland via the issue of citizenship (in the referendum of 2004). While hegemonic ideas on the racial purity of indigenous populations and the highly ambivalent attitudes and policies on immigration pursued over the last decade are characteristi...

Dynamic optimal foraging theory explains vertical migrations of bigeye tuna

DEFF Research Database (Denmark)

Thygesen, Uffe Høgsbro; Sommer, Lene; Evans, Karen

2016-01-01

Bigeye tuna are known for remarkable daytime vertical migrations between deep water, where food is abundant but the water is cold, and the surface, where water is warm but food is relatively scarce. Here we investigate if these dive patterns can be explained by dynamic optimal foraging theory...... behaves such as to maximize its energy gains. The model therefore provides insight into the processes underlying observed behavioral patterns and allows generating predictions of foraging behavior in unobserved environments...

Hydrobiological study of the small stream on the Czech–Moravian Highlands

Directory of Open Access Journals (Sweden)

Ivo Sukop

2010-01-01

Full Text Available Zoobenthos of the Fryšávka Rivulet was investigated in the years 2007–2008. Research included also physico-chemical factors of water (temperature, pH, conductivity, oxygen saturation. Altogether, 144 taxa of zoobenthos were determined in the Fryšávka Rivulet: Coelenterata (1 taxon, Turbellaria (1 taxon, Oligochaeta (6 taxa, Hirudinea (1 taxon, Mollusca (5 taxa, Amphipoda (1 taxon, Decapoda (1 taxon, Acari (1 taxon, Ephemeroptera (18 taxa, Plecoptera (18 taxa, Heteroptera (1 taxon, Megaloptera (1 taxon, Planipennia (1 taxon, Trichoptera (36 taxa, Coleoptera (8 taxa, Diptera (44 taxa. Altogether, 76 taxa of zoobenthos were determined in Medlovka brook: Coelenterata (1 taxon, Turbellaria (1 taxon, Oligochaeta (2 taxa, Mollusca (1 taxon, Isopoda (1 taxon, Amphipoda (1 taxon, Acari (1 taxon, Ephemeroptera (14 taxa, Plecoptera (8 taxa, Megaloptera (1 taxon, Trichoptera (17 taxa, Coleoptera (6 taxa, Diptera (22 taxa.The average abundance of zoobenthos of the Fryšávka Rivulet was 3208 ind.m−2, the average biomass was 7.5 g . m−2, respectively. The same values for the Medlovka brook were: abundance 3238 ind.m−2 and biomass 5.8 g . m−2. The average value of the saprobic index for the whole Fryšávka Rivulet was 1.25 (oligosaprobity, for the Medlovka brook 1.42 (oligosaprobity.

Social cognitive theories used to explain physical activity behavior in adolescents: a systematic review and meta-analysis.

Science.gov (United States)

Plotnikoff, Ronald C; Costigan, Sarah A; Karunamuni, Nandini; Lubans, David R

2013-05-01

To systematically review and examine the explanatory power of key social-cognitive theories used to explain physical activity (PA) intention and behavior, among adolescents. A systematic review and meta-analysis of the literature was performed using the electronic databases Medline, Cumulative Index to Nursing and Allied Health Literature, SPORTdiscus, EBSCO and Education Resources Information Center, Proquest Education Journals Collection, Science Direct, Web of Science and Scopus for social-cognitive theories (i.e., Health Promotion Model, Theory of Planned Behavior, Theory of Reasoned Action, Protection Motivation Theory, Social Cognitive Theory/Self-Efficacy Theory, Health Belief Model, Self-Determination Theory, Transtheoretical Model) used to explain PA intention and behavior. Related keywords in titles, abstracts, or indexing fields were searched. Twenty-three studies satisfied the inclusion criteria and were retained for data extraction and analysis; 16 were cross-sectional studies and seven were longitudinal studies. Most studies employed self-report measures. In general, the models explained greater proportions of variance for intention compared to behavior. The meta-analyses revealed 33% and 48% of the variance respectively for PA and intention were explained by social cognitive models. Few studies have tested the predictive capacity of social cognitive theories to explain objectively measured PA. The majority of PA variance remains unexplained and more theoretical research is needed. Copyright © 2013 Elsevier Inc. All rights reserved.

Assessing the impact of autonomous motivation and psychological need satisfaction in explaining adherence to an exercise referral scheme.

Science.gov (United States)

Eynon, Michael John; O'Donnell, Christopher; Williams, Lynn

2017-10-01

Given the mixed findings concerning self-determination theory in explaining adherence to exercise referral schemes (ERS), the present study attempted to examine whether autonomous motivation and psychological need satisfaction could predict ERS adherence. Participants referred to an 8-week ERS completed self-report measures grounded in self-determination theory and basic needs theory at baseline (N = 124), mid-scheme (N = 58), and at the end of the scheme (N = 40). Logistic regressions were used to analyse the data. Autonomous motivation measured at mid-scheme explained between 12 and 16% of the variance in ERS adherence. Autonomy, relatedness and competence measured at mid-scheme explained between 18 and 26% of the variance in ERS adherence. This model also explained between 18 and 25% when measured at the end of the scheme. The study found limited evidence for the role of autonomous motivation in explaining ERS adherence. Stronger support was found for the satisfaction of the three needs for autonomy, relatedness and competence in predicting ERS adherence. Future research should tap into the satisfaction of all three needs collectively to help foster ERS adherence.

Automatically explaining machine learning prediction results: a demonstration on type 2 diabetes risk prediction.

Science.gov (United States)

Luo, Gang

2016-01-01

Predictive modeling is a key component of solutions to many healthcare problems. Among all predictive modeling approaches, machine learning methods often achieve the highest prediction accuracy, but suffer from a long-standing open problem precluding their widespread use in healthcare. Most machine learning models give no explanation for their prediction results, whereas interpretability is essential for a predictive model to be adopted in typical healthcare settings. This paper presents the first complete method for automatically explaining results for any machine learning predictive model without degrading accuracy. We did a computer coding implementation of the method. Using the electronic medical record data set from the Practice Fusion diabetes classification competition containing patient records from all 50 states in the United States, we demonstrated the method on predicting type 2 diabetes diagnosis within the next year. For the champion machine learning model of the competition, our method explained prediction results for 87.4 % of patients who were correctly predicted by the model to have type 2 diabetes diagnosis within the next year. Our demonstration showed the feasibility of automatically explaining results for any machine learning predictive model without degrading accuracy.

The use of Rich and Suter diagrams to explain the electron configurations of transition elements

Energy Technology Data Exchange (ETDEWEB)

Orofino, Hugo; Machado, Sergio P.; Faria, Roberto B., E-mail: faria@iq.ufrj.br [Instituto de Quimica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ (Brazil)

2013-09-01

Rich and Suter diagrams are a very useful tool to explain the electron configurations of all transition elements, and in particular, the s{sup 1} and s{sup 0} configurations of the elements Cr, Cu, Nb, Mo, Ru, Rh, Pd, Ag, and Pt. The application of these diagrams to the inner transition elements also explains the electron configurations of lanthanoids and actinoids, except for Ce, Pa, U, Np, and Cm, whose electron configurations are indeed very special because they are a mixture of several configurations. (author)

The use of Rich and Suter diagrams to explain the electron configurations of transition elements

Directory of Open Access Journals (Sweden)

Hugo Orofino

2013-01-01

Full Text Available Rich and Suter diagrams are a very useful tool to explain the electron configurations of all transition elements, and in particular, the s¹ and s0 configurations of the elements Cr, Cu, Nb, Mo, Ru, Rh, Pd, Ag, and Pt. The application of these diagrams to the inner transition elements also explains the electron configurations of lanthanoids and actinoids, except for Ce, Pa, U, Np, and Cm, whose electron configurations are indeed very special because they are a mixture of several configurations.

Explaining Helping Behavior in a Cooperative Learning Classroom Setting Using Attribution Theory

Science.gov (United States)

Ahles, Paula M.; Contento, Jann M.

2006-01-01

This recently completed study examined whether attribution theory can explain helping behavior in an interdependent classroom environment that utilized a cooperative-learning model. The study focused on student participants enrolled in 6 community college communication classes taught by the same instructor. Three levels of cooperative-learning…

Explaining the power-law distribution of human mobility through transportation modality decomposition

Science.gov (United States)

Zhao, Kai; Musolesi, Mirco; Hui, Pan; Rao, Weixiong; Tarkoma, Sasu

2015-03-01

Human mobility has been empirically observed to exhibit Lévy flight characteristics and behaviour with power-law distributed jump size. The fundamental mechanisms behind this behaviour has not yet been fully explained. In this paper, we propose to explain the Lévy walk behaviour observed in human mobility patterns by decomposing them into different classes according to the different transportation modes, such as Walk/Run, Bike, Train/Subway or Car/Taxi/Bus. Our analysis is based on two real-life GPS datasets containing approximately 10 and 20 million GPS samples with transportation mode information. We show that human mobility can be modelled as a mixture of different transportation modes, and that these single movement patterns can be approximated by a lognormal distribution rather than a power-law distribution. Then, we demonstrate that the mixture of the decomposed lognormal flight distributions associated with each modality is a power-law distribution, providing an explanation to the emergence of Lévy Walk patterns that characterize human mobility patterns.

Does religiosity explain economic outcomes? Understanding religiosity is crucial to informed policy making

Czech Academy of Sciences Publication Activity Database

Popova, Olga

(2017), č. článku 335. E-ISSN 2054-9571 Institutional support: RVO:67985998 Keywords : religiosity * economic outcomes Subject RIV: AH - Economics https://wol.iza.org/articles/does-religiosity-explain-economic-outcomes/long

ROLE OF PARENTS' ADJUSTMENT IN EXPLAINING PERCEPTION OF ADOLESCENTS' NEGATIVE INTERACTIONS WITH MOTHER AND FATHER

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Tamara Efendić-Spahić

2014-04-01

Full Text Available The research was conducted with the aim of examining the contribution of facets of the adjustment of mother and father for explaining the adolescents’ perception of negative relations with parents. The following adjustment measures were used in this research: anxiety, hypersensitivity, inner coherence, interpersonal orientation and aggression of mother and father individually. The measures of negative interactions between adolescents and parents are conceptualized through the dimension of negative relations with parents, which includes adolescents’ assessment regarding the rejection by father and mother and the assessment of negative relations with father and mother. The research was conducted on a sample including 273 subjects in total: 47 female subjects, 44 male subjects and their parents. For testing the hypotheses, the multiple regression analysis was used. The obtained results show that adjustment facets are important predictors for explaining the perception of negative relations with father. The facet of aggression stands as the most significant predictor among adjustment factors for the group of fathers. For the group of mothers, adjustment did not prove a significant predictor for explaining perception of negative relations. Possible explanations for a modest contribution of mother’s adjustment can be found in the possibility for the quality of family interactions with mother is more explained by an emotional relation that is established between her and the child in early childhood and does not change its quality at later development stages.

Cambios en el uso de la ostra perlera Pinctada mazatlanica (Bivalvia: Pteriidae en el Templo Mayor de Tenochtitlan Changes in the use of the pearl oyster Pinctada mazatlanica (Bivalvia: Pteriidae in the Great Temple of Tenochtitlan

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Adrián Velázquez

2007-10-01

Full Text Available La concha del bivalvo panámico Pinctada mazatlanica fue ampliamente utilizada por las antiguas sociedades del México prehispánico; en las ofrendas enterradas en el Templo Mayor de Tenochtitlan se han encontrado alrededor de 600 objetos elaborados con ella, la mayor parte de los cuales proceden de la etapa constructiva IV (1440-1481, lo que llama la atención, ya que para entonces los mexicas no habían logrado conquistar emplazamientos en la costa del Pacífico. En los sucesivos agrandamientos arquitectónicos es notable el descenso en los objetos de la referida ostra, lo cual en principio se explicó por la mayor destrucción que éstos habían sufrido; sin embargo, el hallazgo de varios ricos depósitos en el predio conocido como Casa de las Ajaracas, correspondientes al reinado de Moctezuma II (1502-1521, en los que prácticamente se encuentra ausente la Pinctada mazatlanica, da lugar a nuevas interpretaciones. En el presente trabajo se presentan 2 posibles hipótesis para explicar el hecho anterior.The nacreous shell of the tropical Pacific mollusc Pinctada mazatlanica was widely used by the ancient inhabitants of Mexico. Around 600 pieces made of this shell have been found in offerings buried in the Great Temple of Tenochtitlan. Most of these objects come from the IVth construction stage (1440-1481, prior to the conquest of the Pacific Coast by the Aztecs. It was previously thought that the considerably smaller numbers found in the following stages were due to the greater degree of destruction suffered by the temple. Nevertheless, the almost complete absence of this material in nine offerings found recently corresponding to the VIIth construction stage (1502-1521, raise other possibilities. In this work two different hypotheses are presented to explain this observation.

Value Chain Envy: Explaining New Entry and Vertical Integration in Popular Music

NARCIS (Netherlands)

Mol, J.M.; Wijnberg, N.M.; Carroll, C.

2005-01-01

The concepts of value creation, value capture, and value protection are employed to explain new entry and vertical integration. It is posited that if, at one stage of the value system, the share of value captured is disproportionally higher than the share of value created, value chain envy will

Value chain envy : Explaining new entry and vertical integration in popular music

NARCIS (Netherlands)

Mol, J.M.; Wijnberg, N.M.; Carroll, C.

The concepts of value creation, value capture, and value protection are employed to explain new entry and vertical integration. It is posited that if, at one stage of the value system, the share of value captured is disproportionally higher than the share of value created, value chain envy will

The Sensitization Model to Explain How Chronic Pain Exists Without Tissue Damage

NARCIS (Netherlands)

van Wilgen, C. Paul; Keizer, Doeke

The interaction of nurses with chronic pain patients is often difficult. One of the reasons is that chronic pain is difficult to explain, because no obvious anatomic defect or tissue damage is present. There is now enough evidence available indicating that chronic pain syndromes such as low back

Will Not Want: Self-Control Rather than Motivation Explains the Female Advantage in Report Card Grades

Science.gov (United States)

Duckworth, Angela L.; Shulman, Elizabeth P.; Mastronarde, Andrew J.; Patrick, Sarah D.; Zhang, Jinghui; Druckman, Jeremy

2015-01-01

Girls earn better grades than boys, but the mechanism explaining this gender difference is not well understood. We examined the relative importance of self-control and motivation in explaining the female advantage in grades. In Study 1, we surveyed middle school teachers and found they judged girls to be higher in both school motivation and self-control. In Studies 2 and 3—using self-reported motivation and teacher- and/or parent-reported self-control, and quarterly and final grades obtained from school records—we find that self-control, but not school motivation, helps to explain the gender gap in academic performance. In these studies, girls appeared to be more self-controlled than boys, but—contrary to teacher judgments in Study 1—did not appear to be more motivated to do well in school. PMID:25883522

Clinical profile of HIV infection

Directory of Open Access Journals (Sweden)

Khopkar Uday

1992-01-01

Full Text Available HIV seropositivity rate of 14 percent was observed amongst STD cases. Heterosexual contact with prostitutes was the main risk factor. Fever, anorexia, weight loss, lymphadenopathy and tuberculosis were useful clinical leads. Genital ulcers, especially chancroid, were common in seropositivies. Alopecia of unknown cause, atypical pyoderma, seborrhea, zoster, eruptive mollusca and sulfa-induced erythema multiforme were viewed with suspicion in high risk groups. Purpura fulminans, fulminant chancroid, vegetating pyoderma and angioedema with purpura were unique features noted in this study.

Climate and terrain factors explaining streamflow response and recession in Australian catchments

Directory of Open Access Journals (Sweden)

A. I. J. M. van Dijk

2010-01-01

Full Text Available Daily streamflow data were analysed to assess which climate and terrain factors best explain streamflow response in 183 Australian catchments. Assessed descriptors of catchment response included the parameters of fitted baseflow models, and baseflow index (BFI, average quick flow and average baseflow derived by baseflow separation. The variation in response between catchments was compared with indicators of catchment climate, morphology, geology, soils and land use. Spatial coherence in the residual unexplained variation was investigated using semi-variogram techniques. A linear reservoir model (one parameter; recession coefficient produced baseflow estimates as good as those obtained using a non-linear reservoir (two parameters and for practical purposes was therefore considered an appropriate balance between simplicity and explanatory performance. About a third (27–34% of the spatial variation in recession coefficients and BFI was explained by catchment climate indicators, with another 53% of variation being spatially correlated over distances of 100–150 km, probably indicative of substrate characteristics not captured by the available soil and geology data. The shortest recession half-times occurred in the driest catchments and were attributed to intermittent occurrence of fast-draining (possibly perched groundwater. Most (70–84% of the variation in average baseflow and quick flow was explained by rainfall and climate characteristics; another 20% of variation was spatially correlated over distances of 300–700 km, possibly reflecting a combination of terrain and climate factors. It is concluded that catchment streamflow response can be predicted quite well on the basis of catchment climate alone. The prediction of baseflow recession response should be improved further if relevant substrate properties were identified and measured.

Explaining Consumer Safe Food Handling Through Behavior-Change Theories: A Systematic Review.

Science.gov (United States)

Young, Ian; Reimer, Danielle; Greig, Judy; Meldrum, Richard; Turgeon, Patricia; Waddell, Lisa

2017-11-01

Consumers often engage in unsafe food handling behaviors at home. Previous studies have investigated the ability of behavior-change theories to explain and predict these behaviors. The purpose of this review was to determine which theories are most consistently associated with consumers' safe food handling behaviors across the published literature. A standardized systematic review methodology was used, consisting of the following steps: comprehensive search strategy; relevance screening of identified references; confirmation of relevance and characterization of relevant articles; risk-of-bias assessment; data extraction; and descriptive analysis of study results. A total of 20 relevant studies were identified; they were mostly conducted in Australia (40%) and the United States (35%) and used a cross-sectional design (65%). Most studies targeted young adults (65%), and none focused on high-risk consumer groups. The outcomes of 70% of studies received high overall risk-of-bias ratings, largely due to a lack of control for confounding variables. The most commonly applied theory was the Theory of Planned Behavior (45% of studies), which, along with other investigated theories of behavior change, was frequently associated with consumer safe food handling behavioral intentions and behaviors. However, overall, there was wide variation in the specific constructs found to be significantly associated and in the percentage of variance explained in each outcome across studies. The results suggest that multiple theories of behavior change can help to explain consumer safe food handling behaviors and could be adopted to guide the development of future behavior-change interventions. In these contexts, theories should be appropriately selected and adapted to meet the needs of the specific target population and context of interest.

A theory with consolidation: Linking everything to explain everything

Science.gov (United States)

Biraris, Gaurav Shantaram

The paper reports a theory which gives explicit (ontic) understanding of the abstract (epistemic) mechanisms spanning many branches of physics. It results to most modern physics starting from Newtonian physics by abandoning progress in twentieth century. The theory assumes consolidation of points in 4-balls of specific radius in the universe. Thus the 4-balls are fundamental elements of the universe. Analogue of momentum defined as soul vector is assumed to be induced on the 4-balls at the beginning of the universe. Then with progression of local time, collisions happen leading to different rotations of CNs. For such rotations, the consolidation provides centripetal binding. By using general terminologies of force and work, the mass energy mechanism gets revealed. The theory provides explicit interpretation of intrinsic properties of mass, electric charge, color charge, weak charge, spin etc. It also provides explicit understanding of the wave-particle duality & quantum mechanics. Epistemic study of the universe with the consolidation results to conventional quantum theories. Elementary mechanism of the field interactions is evident due to conservation of the soul vectors, and its epistemic expectation results to the gauge theories. The theory predicts that four types of interaction would exist in the universe along with the acceptable relative strengths; it provides fundamental interpretation of the physical forces. Further, it explains the basic mechanisms which can be identified with dark energy & dark matter. It also results to (or explains) entanglement, chirality, excess of matter, 4-component spinor, real-abstract (ontic-epistemic) correspondence etc. The theory is beyond standard model and results to the standard model, relativity, dark energy & dark matter, starting by simple assumptions.

Strange history: the fall of Rome explained in Hereditas.

Science.gov (United States)

Bengtsson, Bengt O

2014-12-01

In 1921 Hereditas published an article on the fall of Rome written by the famous classical scholar Martin P:son Nilsson. Why was a paper on this unexpected topic printed in the newly founded journal? To Nilsson, the demise of the Roman Empire was explained by the "bastardization" occurring between "races" from different parts of the realm. Offspring from mixed couples were of a less stable "type" than their parents, due to the breaking up by recombination of the original hereditary dispositions, which led to a general loss of competence to rule and govern. Thus, the "hardness" of human genes, together with their recombination, was - according to Nilsson - the main cause of the fall of Rome. Nilsson's argument is not particularly convincingly presented. Human "races" are taken to have the same genetic structure as inbred crop strains, and Nilsson believes in a metaphysical unity between the individual and the race to which it belongs. However, in my view, Martin P:son Nilsson and his friend Herman Nilsson-Ehle had wider aims with the article than to explain a historical event. The article can be read as indicating strong support from the classical human sciences to the ambitious new science of genetics. Support is also transferred from genetics to the conservative worldview, where the immutability and inflexibility of the Mendelian genes are used to strengthen the wish for greater stability in politics and life. The strange article in Hereditas can, thus, be read as an early instance in the - still ongoing - tug-of-war between the conservative and the liberal ideological poles over how genetic results best are socially interpreted. © 2015 The Authors.

Social processes explaining the benefits of Al-Anon participation.

Science.gov (United States)

Timko, Christine; Halvorson, Max; Kong, Calvin; Moos, Rudolf H

2015-12-01

This study examined social processes of support, goal direction, provision of role models, and involvement in rewarding activities to explain benefits of participating in Al-Anon, a 12-step mutual-help program for people concerned about another person's substance use. Newcomers to Al-Anon were studied at baseline and 6 months later, at which time they were identified as having either sustained attendance or dropped out. Among both newcomers and established Al-Anon members ("old-timers"), we also used number of Al-Anon meetings attended during follow-up to indicate extent of participation. Social processes significantly mediated newcomers' sustained attendance status versus dropped out and outcomes of Al-Anon in the areas of life context (e.g., better quality of life, better able to handle problems due to the drinker), improved positive symptoms (e.g., higher self-esteem, more hopeful), and decreased negative symptoms (e.g., less abuse, less depressed). Social processes also significantly mediated newcomers' number of meetings attended and outcomes. However, among old-timers, Al-Anon attendance was not associated with outcomes, so the potential mediating role of social processes could not be examined, but social processes were associated with outcomes. Findings add to the growing body of work identifying mechanisms by which 12-step groups are effective, by showing that bonding, goal direction, and access to peers in recovery and rewarding pursuits help to explain associations between sustained Al-Anon participation among newcomers and improvements on key concerns of Al-Anon attendees. Al-Anon is free of charge and widely available, making it a potentially cost-effective public health resource for help alleviating negative consequences of concern about another's addiction. (c) 2016 APA, all rights reserved).

String theory: A brand new theory that claims to explain everything in existence

International Nuclear Information System (INIS)

Pal, P.B.

1988-01-01

Background of the origin of the string theories which have shown possibilities of unifying all four basic forces including gravity is described and the concepts behind these theories are explained for the layman. (M.G.R.)

Explaining Racial Disparities in Child Asthma Readmission Using a Causal Inference Approach.

Science.gov (United States)

Beck, Andrew F; Huang, Bin; Auger, Katherine A; Ryan, Patrick H; Chen, Chen; Kahn, Robert S

2016-07-01

Childhood asthma is characterized by disparities in the experience of morbidity, including the risk for readmission to the hospital after an initial hospitalization. African American children have been shown to have more than 2 times the hazard of readmission when compared with their white counterparts. To explain why African American children are at greater risk for asthma-related readmissions than white children. This study was completed as part of the Greater Cincinnati Asthma Risks Study, a population-based, prospective, observational cohort. From August 2010 to October 2011, it enrolled 695 children, aged 1 to 16 years, admitted for asthma or wheezing who identified as African American (n = 441) or white (n = 254) in an inpatient setting of an urban, tertiary care children's hospital. The main outcome was time to asthma-related readmission and race was the predictor. Biologic, environmental, disease management, access, and socioeconomic hardship variables were measured; their roles in understanding racial readmission disparities were conceptualized using a directed acyclic graphic. Inverse probability of treatment weighting balanced African American and white children with respect to key measured variables. Racial differences in readmission hazard were assessed using weighted Cox proportional hazards regression and Kaplan-Meier curves. The sample was 65% male (n = 450), and the median age was 5.4 years. African American children were 2.26 times more likely to be readmitted than white children (95% CI, 1.56-3.26). African American children significantly differed with respect to nearly every measured biologic, environmental, disease management, access, and socioeconomic hardship variable. Socioeconomic hardship variables explained 53% of the observed disparity (hazard ratio, 1.47; 95% CI, 1.05-2.05). The addition of biologic, environmental, disease management, and access variables resulted in 80% of the readmission disparity being explained. The

A third alternative to explain recent observations: Future deceleration

Energy Technology Data Exchange (ETDEWEB)

Chakraborty, Subenoy, E-mail: schakraborty@math.jdvu.ac.in; Pan, Supriya, E-mail: span@research.jdvu.ac.in; Saha, Subhajit, E-mail: subhajit1729@gmail.com

2014-11-10

In the present work we discuss a third alternative to explain the latest observational data concerning the accelerating Universe and its different stages. The particle creation mechanism in the framework of non-equilibrium thermodynamics is considered as a basic cosmic mechanism acting on the flat FRW geometry. By assuming that the gravitationally induced particle production occurs under “adiabatic” conditions, the deceleration parameter is expressed in terms of the particle creation rate which is chosen as a truncated power series of the Hubble parameter. The model shows the evolution of the Universe starting from inflation to the present late time acceleration and it also predicts future decelerating stage.

A third alternative to explain recent observations: Future deceleration

Science.gov (United States)

Chakraborty, Subenoy; Pan, Supriya; Saha, Subhajit

2014-11-01

In the present work we discuss a third alternative to explain the latest observational data concerning the accelerating Universe and its different stages. The particle creation mechanism in the framework of non-equilibrium thermodynamics is considered as a basic cosmic mechanism acting on the flat FRW geometry. By assuming that the gravitationally induced particle production occurs under "adiabatic" conditions, the deceleration parameter is expressed in terms of the particle creation rate which is chosen as a truncated power series of the Hubble parameter. The model shows the evolution of the Universe starting from inflation to the present late time acceleration and it also predicts future decelerating stage.