Miracle-dz/UniFAR-FTUs huggingface dataset:
Modelling of oxygen-isotope data from the Sarmiento ophiolite complex, Chile

Summary The results of an oxygen-isotope investigation of the Sarmiento ophiolite complex show that the extrusive rocks are isotopically enriched in 18O compared to fresh basalts as a consequence of low-temperature interaction with seawater. The basaltic sheeted dykes, dykes cross-cutting plutonic rocks, and the plutonic rocks themselves are depleted in 18O compared to fresh basalts as a consequence of high-temperature interaction with seawater. K2O contents of pillow lavas indicate minimum water/rock ratios of 15 to 90. Within the sheeted dyke complex and the plutonic section, the inferred water/rock ratios become <0.6. Modelling of basalt-seawater interaction indicates that hydrothermal fluids in equilibrium with actinolite-facies assemblages (525–700°C) have δ18O=+5 to +7‰, whereas hydrothermal fluids in equilibrium with greenschist-facies assemblages (230–525°C) have δ18O=0 to +5‰. It appears that an inverse correlation exists between the temperature of metamorphism and the water/rock ratio. This would be anticipated from the cooling effect that circulating seawater has on the oceanic crust.
Stress and pore pressure in saturated clay subjected to heat from radioactive waste: a numerical simulation

Some effects of temperature increase due to the emplacement of radioactive waste on the mechanical and hydraulic behavior of saturated clays are studied numerically. A mass-transfer model is adopted which simulates a possible degeneration of adsorbed water into bulk water at temperatures up to 150 °C. In contrast with a previous paper by the authors the heat output decreases with time to realistically simulate the effect of nuclear waste. Numerical results show that in the vicinity of the line heat source, a much lower value of excess pore pressure and faster propagation of the excess pore-pressure front are obtained because of the substantial increase in permeability arising from the adsorbed water degeneration at elevated temperatures. Moreover, the adsorbed water degeneration accelerates the water flow around the heat source. It is also concluded that over a long term the thermally induced degeneration of absorbed water into bulk water mitigates the possibility of thermal failure of clays surrounding t.
The factors affecting sperm binding to the zona pellucida in the hemizona binding assay.

Sperm binding to the zona pellucida is a prerequisite for fertilization. the hemizona binding assay (HZA) is commonly used to evaluate the zone-binding capacity of spermatozoa. The present study reports three factors that affect HZA. They were the base medium used, the protein source and the size of pipette used for removing loosely bound spermatozoa during HZA. The number of spermatozoa bound on the hemizona was compared between (1) Earle's balanced salt solution (EBSS) and Ham's F-10, and (2) between human serum and bovine serum albumin (BSA). Results indicated that EBSS and human serum both significantly increase the number of bound spermatozoa when compared to Ham's F-10 (P < 0.0001, paired t-test) and BSA (P < 0.05, paired t-test) respectively. Pipettes of different diameters were used to study the effect of size in removing loosely bound spermatozoa on hemizona. Data showed that the diameter of the pipette should be >/=200 mm, in order not to remove bound spermatozoa excessively. These results emphasize the importance of standardization of the protocol of the hemizona assay worldwide to be able to compare results between different laboratories.
Time-course of oocyte activation, pronucleus formation and cleavage in human oocytes fertilized by intracytoplasmic sperm injection.

Knowledge of the timing of the stages of fertilization in humans is still limited because the time of gamete fusion is not known when pre-ovulatory or in-vitro matured cumulus-enclosed oocytes are inseminated. We therefore studied the morphological nuclear changes in 14 patients' oocytes by means of light microscopic observation at 2, 4, 6, 8, 16, 18 and at 20 h after intracytoplasmic single sperm injection (ICSI). A total of 144 metaphase II oocytes were injected with the spermatozoa of the patients' partners. Out of the 134 oocytes that survived the injection, 93 displayed two pronuclei in the course of the observation period (69%). Out of the 93 normally fertilized oocytes, 21 extruded the second polar body at 2 h after micro-injection (23%) and 63 oocytes at 4 h (68%). Pronuclei appeared as early as 6 h after ICSI in 16 normally fertilized oocytes (17%). At 8 h, 75 (80%) oocytes had two visible pronuclei, at 16 h 92 (99%), at 18 h 76 (82%) and at 20 h 63 (68%). In 24 oocytes (26%) the appearance of pronuclei was asynchronous, while the disappearance of the pronuclei was always synchronous, except in one oocyte. Nine of the 134 successfully injected oocytes showed three equal-sized pronuclei (6.7%). Four of the nine multi-pronucleated oocytes did not extrude the second polar body at all, while the time sequence of appearance of pronuclei was similar to that of the normally fertilized oocytes. (ABSTRACT TRUNCATED AT 250 WORDS)
Sea Ice in the Canadian Arctic Archipelago: Modeling the Past (1950–2004) and the Future (2041–60)

Abstract Considering the recent losses observed in Arctic sea ice and the anticipated future warming due to anthropogenic greenhouse gas emissions, sea ice retreat in the Canadian Arctic Archipelago (CAA) is expected and indeed is already being observed. As most global climate models do not resolve the CAA region, a fine-resolution ice–ocean regional model is developed and used to make a projection of future changes in the CAA sea ice. Results from a historical run (1950–2004) are used to evaluate the model. The model does well in representing observed sea ice spatial and seasonal variability, but tends to underestimate summertime ice cover. The model results for the future (2041–60) show little change in wintertime ice concentrations from the past, but summertime ice concentrations decrease by 45%. The ice thickness is projected to decrease by 17% in the winter and by 36% in summer. Based on this study, a completely ice-free CAA is unlikely by the year 2050, but the simulated ice retreat suggests that th.
Seasonal variability of the surface dynamic topography in the tropical Atlantic Ocean

The seasonal changes of the surface dynamic topography are studied using a merged data set including MBT, XBT and Nansen observations, collected in the 20s-30N tropical Atlantic until 1978. TWO regions of maximum seasonal variability appear. One lies north of the equator extending zonally approximately under the mean position of the Inter-Tropical Convergence Zone (ITCZ). The second one is found in the eastern equatorial region (Gulf of Guinea). The two regions vary out of phase and are separated by a pivot point around 25W in the equatorial plane. Another near 180° phase change is observed at the northern edge of the region of maximum seasonal variability north of the equator. These amplitude and phase changes in the surface dynamic topography are related to a double seasonal tilt of the thermocline recently simulated by several two-layer and multilayer models. The seasonal variability of the geo-strophic part of the North Equatorial Countercurrent (NECC) and of the South Equatorial Current (SEC) is related to these near-equatorial areas of large seasonal dynamic height variability. Their seasonal variations are almost in phase and are found to be maximum in the northern summer season (July-October) and near zero or reversed in the northern winter-spring season (February-May). The seasonal variability of the surface dynamic topography of the tropical Atlantic appears to be in relation to two phenomena: (i) a northern equatorial oceanic response due to the local effect of the seasonal migration of the ITCZ associated to the wind stress change; (ii) an equatorial eastern oceanic response possibly due to the remote effect of this wind stress change and the associated local thermodynamic effects.
Nitrous oxide flux to the atmosphere from the littoral zone of a boreal lake

[1] The surface-atmospheric exchange of nitrous oxide (N2O) was investigated in the vegetated littoral zone of a eutrophied midboreal lake (Lake Kevaton, Finland) with a static chamber technique. During a dry summer (three to six samplings per site), the meadow site and two marsh sites in the temporarily flooded eulittoral zone and the Phragmites australis-dominated site in the continuously flooded infralittoral zone had mean daytime N2O-N emissions from 11 ± 7 to 22 ± 7 μg m−2 h−1, whereas the Nuphar lutea-dominated site in the infralittoral zone had a mean N2O flux close to zero. During a wet summer (13–14 samplings per site), the mean daytime N2O-N fluxes ranged from 4 ± 1 to 15 ± 5 μg m−2 h−1 at the three eulittoral sites and were negligible at the two infralittoral sites. The littoral zone occupied 26% of the lake area but was estimated to account for most of the N2O emissions from the lake. The studied eulittoral zone, which did not have adjacent nitrogen fertilization, exhibited higher N2O emissions during the summer than seen in northern natural ecosystems in general, including peatlands, forests, and the pelagic regions of lakes. Thus in lake-rich landscapes the littoral zone and other lake-associated wetlands must be considered as potential sources of atmospheric N2O. An assessment of their atmospheric importance requires further data on the N2O fluxes and their regulation in different littoral areas and on the total littoral coverage, neither of which is yet available.
Foraminiferal record of marine transgression during deposition of the Middle Miocene Badenian evaporites in Central Paratethys (Borków section, Polish Carpathian Foredeep)

Benthic and planktonic foraminifera from a marly clay intercalation sandwiched between mid‐Badenian (Middle Miocene) gypsum deposited in an environment of an evaporitic shoal (<1 m deep) at Borków (southern Poland) indicate a major marine flooding event in the previously isolated Carpathian Foredeep Basin (Central Paratethys). After this very short‐term environmental change, benthic foraminifers started to colonize a new niche which was previously defaunated, and the pattern of benthic foraminiferal colonization is similar to that related to the reflooding which terminated the Badenian evaporite deposition. The benthic foraminifer assemblages are composed of pioneer, opportunistic, r‐selected species dominated by elphidiids. The connection of the Carpathian Foredeep Basin with the marine reservoir was short‐lived. The marly clay intercalations in evaporite sequences originating in bared basins can thus register major environmental changes.
Synergistic effects of floral phytochemicals against a bumble bee parasite

Abstract Floral landscapes comprise diverse phytochemical combinations. Individual phytochemicals in floral nectar and pollen can reduce infection in bees and directly inhibit trypanosome parasites. However, gut parasites of generalist pollinators, which consume nectar and pollen from many plant species, are exposed to phytochemical combinations. Interactions between phytochemicals could augment or decrease effects of single compounds on parasites. Using a matrix of 36 phytochemical treatment combinations, we assessed the combined effects of two floral phytochemicals, eugenol and thymol, against four strains of the bumblebee gut trypanosome Crithidia bombi. Eugenol and thymol had synergistic effects against C. bombi growth across seven independent experiments, showing that the phytochemical combination can disproportionately inhibit parasites. The strength of synergistic effects varied across strains and experiments. Thus, the antiparasitic effects of individual compounds will depend on both the presence of other phytochemicals and parasite strain identity. The presence of synergistic phytochemical combinations could augment the antiparasitic activity of individual compounds for pollinators in diverse floral landscapes.
Nonlinear Climate Dynamics

1. Climate variability 2. Deterministic dynamical systems 3. Introduction to stochastic calculus 4. Stochastic dynamical systems 5. Analysing data from stochastic dynamical systems 6. The climate modeling hierarchy 7. The North Atlantic Oscillation 8. El Nino variability 9. Multidecadal variability 10. Dansgaard-Oeschger events 11. The Pleistocene ice ages 12. Predictability.
Pristine Moon rocks: A “large” felsite and a metal‐rich ferroan anorthosite

We report new chemical analyses and (in most cases) descriptions for 19 lunar rock samples, including 5 mare basalts from Apollo 15 and 5 uncommonly feldspathic rocklets from Apollo 17. Two of the samples studied are most extraordinary: a “large” (≈1 g) felsite from Apollo 12, and a pristine ferroan anorthosite from Apollo 15 that is unusually rich in Fe-metal and trace siderophile elements. The felsite, 12033,507, is mainly a graphic intergrowth of K-feldspar and a silica phase, with about 6% plagioclase and 1% each of ferroaugite, ilmenite, and fayalitic olivine. This crystalline assemblage is crisscrossed, and apparently intruded by thin veins of brownish, felsic (average SiO2 = 57 wt %) glass. The glass veins are far from uniform in composition; evidently after the glass was intruded it reacted, to varying extents, with the crystalline felsite. Dark globules scattered at apparent nodes in the network of glass veins are interpreted as the least altered of the intruded glasses. These globule glasses are relatively SiO2-poor (average = 48 wt %) but extremely FeO-rich (average = 36 wt %). They may have formed as liquid immiscibility caused the same melt that produced the crystalline felsite to split into Fe-rich melt (the globule glasses) plus Fe-poor, Si-rich melt. According to this model, deformation, most likely caused by an impact, then squeezed the Fe-rich melt into the still nearby, and still hot, crystalline felsite. The Fe-metal content of ferroan anorthosite 15363 is 1.2 wt % in the thin section we studied, but must have been, based on mass balance for Co and Ni, considerably lower in the chip we used for bulk-rock analysis. Even so, the measured bulk-rock concentrations for several siderophile elements (Re, Os, and Ir) are far higher than previously observed among pristine lunar anorthosites. These results underscore the huge uncertainty associated with any attempt to estimate the overall siderophile element contents of the moon's crust. Among pristine rocks from the Apollo 17 site, located on the rim of the Serenitatis Basin, ferroan anorthosites continue to be far outnumbered by Mg-rich rocks.
Clay Minerals in Evaporite Host Rocks, Palo Duro Basin, Texas Panhandle

ABSTRACT The mineralogy and chemical composition of clays in evaporite strata of the Palo Duro Basin, Texas Panhandle, were investigated to determine the type and extent of alteration and to explore the preservation of diagenetic clays in changing geochemical environments. The coarse clay-size fraction (2-8 µm equivalent settling diameter (ESD)) contains predominantly illite and irregularly interlayered chlorite/vermiculite, whereas the fine-clay-size fraction (< 0.5 µm) contains predominantly illite and irregularly interlayered chlorite/smectite. Detrital illite, biotite, chlorite, and smectite are the probable parent clays. Electron microprobe analysis of clay-size flakes shows that the diagenetic clays are enriched in magnesium relative to detrital clays. Chemical composition , the geologic history of the Palo Duro Basin, and comparison to clays from other Paleozoic marine evaporites suggest that alteration occurred syndepositionally in the presence of hypersaline marine evaporite brine. Mineral assemblages of clays encased in primary marine halite, clays from regions where halite has been dissolved, and clays from strata approximately 300 m beneath the salt section are structurally and chemically similar, suggesting that these clay minerals record paleohydrologic and paleoenvironmental conditions.
Avifauna of the Guyana Southern Rupununi, with Comparisons to Other Savannas of Northern South America

Surveys of five sites in the southern Rupununi savanna of Guyana contribute considerably to our knowledge of the species composition, relative abundance, and breeding status of the avifauna of this poorly known region. Highlights from these surveys include the discovery of a previously unknown popu- lation of the endangered Red Siskin (Carduelis cucullata), and an unrecognized cryptic species of flycatcher. Comparison of our Rupununi results with species lists for several major savannas in northern South Amer- ica further supports the conclusion that the avifauna of the Roraima-Rupununi is most similar to the con- tiguous "Gran Sabana" of Venezuela, whereas the Sipaliwini savanna avifauna of southern Suriname is most similar to the Amapa of northeastern Brazil. Details are presented for 30 species, including 10 new for Guyana. Accepted 18 October 2003.
WIKIPEDIA IN HIGHER EDUCATION: AN EMPIRICAL STUDY ON FACULTY PERCEPTIONS AND PRACTICES

Despite the initial sceptical attitude of university faculty towards Wikipedia as a source of reliable information – mainly because of its unclear authorship – an increasing number of teaching experiences using Wikipedia have begun to appear at different universities around the world. These experiences show, in most cases, very satisfactory results and a substantial improvement in various basic skills, as well as a positive influence on the students' motivation. We are undertaking a research project in order to systematically analyze, using a comprehensive empirical study, the perception and attitudes of university faculty from different scholarly areas towards Wikipedia. The study aims (a) to investigate relationships between these perceptions and several faculty characteristics and (b) to establish the extent to which the sceptical attitudes are related to disciplinary or generational factors on the one hand, or to an implicit conflict between the standard scientific or academic epistemological stands and the specific peer-to-peer culture of Wikipedia (as a paradigmatic example of content production in a collaborative open network), on the other. Different studies have explored and documented how a vast majority of university students use Wikipedia very frequently and for different tasks. However, studies on faculty members are scarce and often based on a very limited empirical scope. We have launched an online survey to all faculty members of the Universitat Oberta de Catalunya. The questionnaire was designed to measure different constructs: mainly perceived quality of Wikipedia, teaching practices involving Wikipedia, usage experience, perceived usefulness and use of 2.0 tools. Control items were also included for gathering information on gender, age, teaching experience, academic rank, area of expertise, etc. This work presents and discusses the main preliminary results obtained by the survey. Though most faculty members have got a positive view on the teaching usefulness of Wikipedia, few of them engage in actual teaching uses. Passive use is much more frequent than active and contributory practices are scarce. Nevertheless the proportion of registered users is big and the quality of Wikipedia contents is mostly positively judged. Our analysis also deals with other institutional, professional and individual factors affecting attitudes and practices on Wikipedia.
Hesperian equatorial thermokarst lakes in Ares Vallis as evidence for transient warm conditions on Mars

On Earth, permafrost thawing is linked to climate warming. Similarly, on Mars, permafrost degradation, described from mid-latitude and equatorial settings, is likely linked to global or regional climate change. Putative thermokarst depressions identified on Mars are widely considered to be the result of sublimation, evaporation, or thawing of an ice-rich substrate. The possibility that the depressions formed by melting of permafrost to create alas-like lakes has been recently proposed, but is controversial, owing to the lack of primary evidence for liquid filling the depressions. Here we use high-resolution Mars Reconnaissance Orbiter Context Camera images and derived topographic data to characterize possible thermokarst terrain in Ares Vallis. The terrain comprises subcircular to irregular, flat-floored rimless topographic depressions that occur at varying elevations. We report the discovery of narrow channels connecting thermokarst-like depressions that provide evidence for the previous presence of ponded liquid water. Crater counts on these surfaces indicate resurfacing that is likely related to flood deposition of water-saturated sediments in Ares Vallis during the Hesperian (ca. 3.6–3.0 Ga). We infer that thermokarst lakes formed after flooding by thawing of ice within the sediments during transient warm periods in the Hesperian, a time previously considered to be too cold to permit ice thaw.
Solar Lake (Sinai). 1. Physical and chemical limnology1

In Solar Lake, a basin at the edge of the sea filled with brine and shielded from the wind, a pycnocline builds up in September due to seepage of seawater to the surface. Solar heating produces a mesothermic temperature curve with a maximum up to 60.5°C at 2.5–3-m depth and decreasing temperatures toward the bottom (40°C at 5 m). The temperature profile together with a supply of nutrients from seepage leads to the development of several bacterial plates and a benthic cyanobacterial bloom. A rapid development of anoxic conditions with up to 39 ppm H2S, a decrease in pH from top to bottom (8–6.9), redox potential gradients (+390 to −185 mV), and extremely pronounced light absorption are observed during the period of stratification which lasts from Sepember to July. With increasing solar energy, the seawater supply no longer compensates for the evaporation rate of 3.0 m yr−1 and the mesothermy becomes unstable. During a short period of holomixis, lasting from 4–13 weeks, the temperature is 27°C throughout the water column. The sediments of Solar Lake preserve a record of the last 4,600 years from the conditions of a marine lagoon to the development of the limnological cycle presented here.
Killer whale (Orcinus orca) photo-identification in the eastern Canadian Arctic

We identified individual killer whales (Orcinus orca) using recent (2004–09) photographs to obtain a minimum count of whales that use eastern Canadian Arctic waters. Fifty-three individuals were identified from nine different sightings; 11 individuals from western Hudson Bay sightings and 42 from the areas around northern and eastern Baffin Island. One whale was re-sighted: an adult female or large juvenile photographed 17 days and 375 km apart at Churchill, Manitoba, and off-shore of Rankin Inlet, Nunavut, in August 2007. With only one individual re-sighted, the number of individuals that use this area is likely much larger. No re-sightings occurred between Arctic killer whales and individuals photographed off the coast of Newfoundland. Our results represent the minimum number of killer whales sighted in eastern Canadian Arctic waters and provide the foundation for further killer whale research. Little is known about Arctic killer whales and, as a top predator, it is unclear what effect they have on Arctic marine ecosystems.