A multi-proxy investigation of sediment core GeoB7165-1 and AMS 14C dating points from sediment cores off Conceptión (~ 36°S)

A high-resolution sea surface temperature and paleoproductivity reconstruction on a sedimentary record collected at 36°S off central-south Chile (GeoB 7165-1, 36°33'S, 73°40'W, 797 m water depth, core length 750 cm) indicates that paleoceanographic conditions changed abruptly between 18 and 17 ka. Comparative analysis of several cores along the Chilean continental margin (30°-41°S) suggests that the onset and the pattern of deglacial warming was not uniform off central-south Chile due to the progressive southward migration of the Southern Westerlies and local variations in upwelling. Marine productivity augmented rather abruptly at 13-14 ka, well after the oceanographic changes.We suggest that the late deglacial increase in paleoproductivity off central-south Chile reflects the onset of an active upwelling system bringing nutrient-rich, oxygen-poor Equatorial SubsurfaceWater to the euphotic zone, and a relatively higher nutrient load of the Antarctic Circumpolar Current. During the Last Glacial Maximum, when the Southern Westerlies were located further north, productivity off central-south Chile, in contrast to off northern Chile, was reduced due to direct onshore-blowing winds that prevented coastal upwelling and export production.

Chert intervals in DSDP and ODP sites (Table 1)

Radiolarian cherts in the Tethyan realm of Jurassic age were recently interpreted as resulting from high biosiliceous productivity along upwelling zones in subequatorial paleolatitudes the locations of which were confirmed by revised paleomagnetic estimates. However, the widespread occurrence of cherts in the Eocene suggests that cherts may not always be reliable proxies of latitude and upwelling zones. In a new survey of the global spatio-temporal distribution of Cenozoic cherts in Deep Sea Drilling Project (DSDP) and Ocean Drilling Program (ODP) sediment cores, we found that cherts occur most frequently in the Paleocene and early Eocene, with a peak in occurrences at ~50 Ma that is coincident with the time of highest bottom water temperatures of the early Eocene climatic optimum (EECO) when the global ocean was presumably characterized by reduced upwelling efficiency and biosiliceous productivity. Cherts occur less commonly during the subsequent Eocene global cooling trend. Primary paleoclimatic factors rather than secondary diagenetic processes seem therefore to control chert formation. This timing of peak Eocene chert occurrence, which is supported by detailed stratigraphic correlations, contradicts currently accepted models that involve an initial loading of large amounts of dissolved silica from enhanced weathering and/or volcanism in a supposedly sluggish ocean of the EECO, followed during the subsequent middle Eocene global cooling by more vigorous oceanic circulation and consequent upwelling that made this silica reservoir available for enhanced biosilicification, with the formation of chert as a result of biosilica transformation during diagenesis. Instead, we suggest that basin-basin fractionation by deep-sea circulation could have raised the concentration of EECO dissolved silica especially in the North Atlantic, where an alternative mode of silica burial involving widespread direct precipitation and/or absorption of silica by clay minerals could have been operative in order to maintain balance between silica input and output during the upwelling-deficient conditions of the EECO. Cherts may therefore not always be proxies of biosiliceous productivity associated with latitudinally focused upwelling zones.

The attention/support to students in the socio-labor transition

In the present paper I intend to put forward some inquiries regarding the socio-labor guidance and transition of the young people in the co-ordinates of contemporary society. The outstanding paradox in which some young people are immersed when trying to get a first, second, third employment is also analyzed: "The job of looking for a job". This is a common experience shared by many young people when they try to find a place in the complex labor panorama. Looking for a job is a recurrent situation in contemporary society, given the high dose of precarious employment in which the productive world moves. Life-long jobs belong to the past and what is normal is that people strive to enter the competitive labor market repeatedly. Moreover, the paper offers the partial results of a larger research project that approaches tutorship, decision taking and expectations before the academic-labor future of the studentship in the last years of secondary school. Finally, I suggest some insights in the line that it is not longer feasible to work with old-fashioned guidance, trying to channel people's vocation and offering them information so that they get a job that provides them with the happiness of "doing what you like". Behind these ideas lay the normal biographies, the predictable itineraries. Labor market complexity makes the transition to working life very difficult. Once immersed in it, biographies and labor itineraries are constructed and reconstructed at the rhythm of the changing fortunes of times.

Género y trabajo en el campo argentino. Discursos y representaciones sociales (1946-1962)

La importancia de las labores de las mujeres del mundo rural había sido entendida en términos de arraigo familiar y mayor productividad desde los tiempos del Centenario y enfatizada por el Estado intervencionista desde 1930. El Estado peronista (1946-1955) interpela a las mujeres vinculándolas a los hogares, a la educación de los hijos y a la economía doméstica, profundizando estas pautas culturales anteriores. La Revolución Libertadora (1955-1958) provoca la ruptura de la hegemonía y promueve cambios en la política económica que favorecen a la elite agropecuaria y a la modernización del sistema productivo. El Estado desarrollista (1958-1962) promueve la integración regional y la tecnificación del campo, generando a la vez, una apertura al ingreso de capital extranjero. La dependencia de la economía argentina del mundo rural sustenta, para estos gobiernos, el desarrollo industrial. Estos cambios políticos y económicos en relación al agro permiten preguntar sobre el espacio de las mujeres del ámbito rural y su vida cotidiana en estos discursos. Se pretende, entonces, avanzar sobre las diversas reconstrucciones discursivas de los roles y el trabajo de las mujeres del campo argentino. En este sentido, este trabajo se plantea estudiar cuáles son los roles de las mujeres de campo que se (re)producen en las revistas y libros de lectura desde 1946 a 1962 como legitimados en el orden social de los discursos.

Research and the choice of a course of study

This paper presents some research on the choice of a course of study as related to a certain social, family and labor context. The methodology used included the definition of the theoretical basis and a series of empirical investigations which comprised different kinds of sur- veys, records, observations, participants as well as other fieldwork. The results obtained shed some light on the issue and raise new questions. This study was especially carried out to analyze the choice of the following courses of study: Law, Psychology and the different Teaching Courses.

Benthic carbon turnover, sediment pigment concentrations and sinking fluxes of POC in the southeastern Beaufort Sea during CCGS Amundsen cruise 2008

The effects of changing ice and atmospheric conditions on the upwelling of deep nutrient-laden waters and biological productivity in the coastal Beaufort Sea were quantified using a unique combination of in situ and remote-sensing approaches. Repeated instances of ice ablation and upwelling during fall 2007 and summer 2008 multiplied the production of ice algae, phytoplankton, zooplankton and benthos by 2 to 6 fold. Strong wind forcing failed to induce upward shifts in the biological productivity of stratified waters off the shelf.

The attention/support to students in the socio-labor transition

In the present paper I intend to put forward some inquiries regarding the socio-labor guidance and transition of the young people in the co-ordinates of contemporary society. The outstanding paradox in which some young people are immersed when trying to get a first, second, third employment is also analyzed: "The job of looking for a job". This is a common experience shared by many young people when they try to find a place in the complex labor panorama. Looking for a job is a recurrent situation in contemporary society, given the high dose of precarious employment in which the productive world moves. Life-long jobs belong to the past and what is normal is that people strive to enter the competitive labor market repeatedly. Moreover, the paper offers the partial results of a larger research project that approaches tutorship, decision taking and expectations before the academic-labor future of the studentship in the last years of secondary school. Finally, I suggest some insights in the line that it is not longer feasible to work with old-fashioned guidance, trying to channel people's vocation and offering them information so that they get a job that provides them with the happiness of "doing what you like". Behind these ideas lay the normal biographies, the predictable itineraries. Labor market complexity makes the transition to working life very difficult. Once immersed in it, biographies and labor itineraries are constructed and reconstructed at the rhythm of the changing fortunes of times.

Género y trabajo en el campo argentino. Discursos y representaciones sociales (1946-1962)

La importancia de las labores de las mujeres del mundo rural había sido entendida en términos de arraigo familiar y mayor productividad desde los tiempos del Centenario y enfatizada por el Estado intervencionista desde 1930. El Estado peronista (1946-1955) interpela a las mujeres vinculándolas a los hogares, a la educación de los hijos y a la economía doméstica, profundizando estas pautas culturales anteriores. La Revolución Libertadora (1955-1958) provoca la ruptura de la hegemonía y promueve cambios en la política económica que favorecen a la elite agropecuaria y a la modernización del sistema productivo. El Estado desarrollista (1958-1962) promueve la integración regional y la tecnificación del campo, generando a la vez, una apertura al ingreso de capital extranjero. La dependencia de la economía argentina del mundo rural sustenta, para estos gobiernos, el desarrollo industrial. Estos cambios políticos y económicos en relación al agro permiten preguntar sobre el espacio de las mujeres del ámbito rural y su vida cotidiana en estos discursos. Se pretende, entonces, avanzar sobre las diversas reconstrucciones discursivas de los roles y el trabajo de las mujeres del campo argentino. En este sentido, este trabajo se plantea estudiar cuáles son los roles de las mujeres de campo que se (re)producen en las revistas y libros de lectura desde 1946 a 1962 como legitimados en el orden social de los discursos.

Research and the choice of a course of study

This paper presents some research on the choice of a course of study as related to a certain social, family and labor context. The methodology used included the definition of the theoretical basis and a series of empirical investigations which comprised different kinds of sur- veys, records, observations, participants as well as other fieldwork. The results obtained shed some light on the issue and raise new questions. This study was especially carried out to analyze the choice of the following courses of study: Law, Psychology and the different Teaching Courses.

The attention/support to students in the socio-labor transition

In the present paper I intend to put forward some inquiries regarding the socio-labor guidance and transition of the young people in the co-ordinates of contemporary society. The outstanding paradox in which some young people are immersed when trying to get a first, second, third employment is also analyzed: "The job of looking for a job". This is a common experience shared by many young people when they try to find a place in the complex labor panorama. Looking for a job is a recurrent situation in contemporary society, given the high dose of precarious employment in which the productive world moves. Life-long jobs belong to the past and what is normal is that people strive to enter the competitive labor market repeatedly. Moreover, the paper offers the partial results of a larger research project that approaches tutorship, decision taking and expectations before the academic-labor future of the studentship in the last years of secondary school. Finally, I suggest some insights in the line that it is not longer feasible to work with old-fashioned guidance, trying to channel people's vocation and offering them information so that they get a job that provides them with the happiness of "doing what you like". Behind these ideas lay the normal biographies, the predictable itineraries. Labor market complexity makes the transition to working life very difficult. Once immersed in it, biographies and labor itineraries are constructed and reconstructed at the rhythm of the changing fortunes of times.

Género y trabajo en el campo argentino. Discursos y representaciones sociales (1946-1962)

La importancia de las labores de las mujeres del mundo rural había sido entendida en términos de arraigo familiar y mayor productividad desde los tiempos del Centenario y enfatizada por el Estado intervencionista desde 1930. El Estado peronista (1946-1955) interpela a las mujeres vinculándolas a los hogares, a la educación de los hijos y a la economía doméstica, profundizando estas pautas culturales anteriores. La Revolución Libertadora (1955-1958) provoca la ruptura de la hegemonía y promueve cambios en la política económica que favorecen a la elite agropecuaria y a la modernización del sistema productivo. El Estado desarrollista (1958-1962) promueve la integración regional y la tecnificación del campo, generando a la vez, una apertura al ingreso de capital extranjero. La dependencia de la economía argentina del mundo rural sustenta, para estos gobiernos, el desarrollo industrial. Estos cambios políticos y económicos en relación al agro permiten preguntar sobre el espacio de las mujeres del ámbito rural y su vida cotidiana en estos discursos. Se pretende, entonces, avanzar sobre las diversas reconstrucciones discursivas de los roles y el trabajo de las mujeres del campo argentino. En este sentido, este trabajo se plantea estudiar cuáles son los roles de las mujeres de campo que se (re)producen en las revistas y libros de lectura desde 1946 a 1962 como legitimados en el orden social de los discursos.

Research and the choice of a course of study

This paper presents some research on the choice of a course of study as related to a certain social, family and labor context. The methodology used included the definition of the theoretical basis and a series of empirical investigations which comprised different kinds of sur- veys, records, observations, participants as well as other fieldwork. The results obtained shed some light on the issue and raise new questions. This study was especially carried out to analyze the choice of the following courses of study: Law, Psychology and the different Teaching Courses.

Lithology and organic geochemistry at DSDP Hole 76-534

The organic facies of Early and middle Cretaceous sediments drilled at DSDP Site 534 is dominated by terrestrially derived plant remains and charcoal. Marine organic matter is mixed with the terrestrial components, but through much of this period was diluted by the terrestrial material. The supply of terrestrial organic matter was high here because of the nearness of the shore and high runoff promoted by a humid temperate coastal climate. Reducing conditions favored preservation of both marine and terrestrial organic matter, the terrestrial materials having reached the site mostly in turbidity currents or in the slow-moving, near-bottom nepheloid layer. An increase in the abundance of terrestrial organic matter occurred when the sea level dropped in the Valanginian and again in the Aptian-Albian, because rivers dumped more terrigenous elastics into the Basin and marine productivity was lower at these times than when sea level was high. A model is proposed to explain the predominance of reducing conditions in the Valanginian-Aptian, of oxidizing conditions in the late Aptian, and of reducing conditions in the Albian-Cenomanian. The model involves influx of oxygen-poor subsurface waters from the Pacific at times of high or rising sea level (Valanginian-Aptian, and Albian- Cenomanian) and restriction of that influx at times of low sea level (late Aptian). In the absence of a supply of oxygenpoor deep water, the bottom waters of the North Atlantic became oxidizing in the late Aptian, probably in response to development of a Mediterranean type of circulation. The influx of nutrients from the Pacific led to an increase in productivity through time, accounting for an increase in the proportion of marine organic matter from the Valanginian into the Aptian and from the Albian to the Cenomanian. Conditions were dominantly oxidizing through the Middle Jurassic into the Berriasian, with temporary exceptions when bottom waters became reducing, as in the Callovian. Mostly terrestrial and some marine organic matter accumulated during the Callovian reducing episode. When Jurassic bottom waters were oxidizing, only terrestrial organic matter was buried in the sediments, in very small amounts.

Dinoflagellate cyst assemblages, Mg/Ca based reconstructed temperatures, stable carbon isotopes, and geochemical parameters of sediment core GeoB9508-5

In order to investigate a possible connection between tropical northeast (NE) Atlantic primary productivity, Atlantic meridional overturning circulation (AMOC), and drought in the Sahel region during Heinrich Stadial 1 (HS1), we used dinoflagellate cyst (dinocyst) assemblages, Mg/Ca based reconstructed temperatures, stable carbon isotopes (d13C) and geochemical parameters of a marine sediment core (GeoB 9508-5) from the continental slope offshore Senegal. Our results show a two-phase productivity pattern within HS1 that progressed from an interval of low marine productivity between ~ 19 and 16 kyr BP to a phase with an abrupt and large productivity increase from ~ 16 to 15 kyr BP. The second phase is characterized by distinct heavy planktonic d13C values and high concentrations of heterotrophic dinocysts in addition to a significant cooling signal based on reconstructions of past sea surface temperatures (SST). We conclude that productivity variations within HS1 can be attributed to a substantial shift of West African atmospheric processes. Taken together our results indicate a significant intensification of the North East (NE) trade winds over West Africa leading to more intense upwelling during the last millennium of HS1 between ~ 16 and 15 kyr BP, thus leaving a strong imprint on the dinocyst assemblages and sea surface conditions. Therefore, the two-phase productivity pattern indicates a complex hydrographic setting suggesting that HS1 cannot be regarded as uniform as previously thought.

Palynology and dinoflagellate counts of surface sediments, and sea surface conditions, of sites in the North Pacific

Palynological analyses were performed on 53 surface sediment samples from the North Pacific Ocean, including the Bering and Okhotsk Seas (37-64°N, 144°E-148°W), in order to document the relationships between the dinocyst distribution and sea-surface conditions (temperatures, salinities, primary productivity and sea-ice cover). Samples are characterized by concentrations ranging from 18 to 143816 cysts/cm**3 and the occurrence of 32 species. A canonical correspondence analysis (CCA) was carried out to determine the relationship between environmental variables and the distribution of dinocyst taxa. The first and second axes represent, respectively, 47% and 17.8% of the canonical variance. Axis 1 is positively correlated with all parameters except to the sea-ice and primary productivity in August, which are on the negative side. Results indicate that the composition of dinocyst assemblages is mostly controlled by temperature and that all environmental variables are correlated together. The CCA distinguishes 3 groups of dinocysts: the heterotrophic taxa, the genera Impagidinium and Spiniferites as well as the cyst of Pentapharsodinium dalei and Operculodinium centrocarpum. Five assemblage zones can be distinguished: 1) the Okhotsk Sea zone, which is associated to temperate and eutrophic conditions, seasonal upwellings and Amur River discharges. It is characterized by the dominance of O. centrocarpum, Brigantedinium spp. and Islandinium minutum; 2) the Western Subarctic Gyre zone with subpolar and mesotrophic conditions due to the Kamchatka Current and Alaska Stream inflows. Assemblages are dominated by Nematosphaeropsis labyrinthus, Pyxidinopsis reticulata and Brigantedinium spp.; 3) the Bering Sea zone, depicting a subpolar environment, influenced by seasonal upwellings and inputs from the Anadyr and Yukon Rivers. It is characterized by the dominance of I. minutum and Brigantedinium spp.; 4) the Alaska Gyre zone with temperate conditions and nutrient-enriched surface waters, which is dominated by N. labyrinthus and Brigantedinium spp. and 5) the Kuroshio Extension-North Pacific-Subarctic Current zone characterized by a subtropical and oligotrophic environment, which is dominated by O. centrocarpum, N. labyrinthus and warm taxa of the genus Impagidinium. Transfer functions were tested using the modern analog technique (MAT) on the North Pacific Ocean (= 359 sites) and the entire Northern Hemisphere databases ( = 1419 sites). Results confirm that the updated Northern Hemisphere database is suitable for further paleoenvironmental reconstructions, and the best results are obtained for temperatures with an accuracy of +/-1.7 °C.