bluuebunny/crossref_metadata_2025 huggingface dataset:
Éthique et activité mathématique
Authors: Maheux Jean-François , Proulx Jérôme
Published: August 2017

Les questions éthico-morales occupent généralement peu de place dans le contexte de l’enseignement des mathématiques. Nous proposons toutefois, ici, une perspective qui en fait un élément central, tant du point de vue du chercheur, de l’enseignant que de l’élève. Discutant de diverses études en didactique des mathématiques qui traitent des questions éthico-morales, nous présentons une approche inspirée des écrits de Levinas et de nos travaux des dernières années sur l’épistémologie de l’activité mathématique. Cette perspective invite à voir l’enseignement des mathématiques comme l’occasion d’une expérience d’altérité où une sensibilité au faire-ensemble se développe. Nous visitons donc du point de vue de l’activité mathématique les thèmes de l’altérité, de la responsabilité et de l’impossibilité éthique du savoir qui sont au coeur du travail de Levinas. Cela nous mène à souligner certains défis, mais aussi certaines possibilités pour une telle éthique du faire-ensemble mathématique en contexte scolaire.
Militer par le témoignage public : défis et retombées pour les communautés sexuelles et de genres
Authors: Mensah Maria Nengeh , Bastien Charlebois Janik , Vallerand Olivier , Wesley Sandra , Monteith Ken
Published: August 2017

Dans cet article, nous nous penchons sur l’expérience du militantisme par le biais des témoignages de personnes qui luttent pour l’inclusion sociale de leurs communautés sexuelles et de genres. Nous décrivons l’expérience de militantes et militants issus de trois groupes sociaux minorisés en raison de leur sexualité et de leur expression de genre ou du développement de leur corps sexué : les personnes lesbiennes, gaies, bisexuelles, trans, queer et intersexes (LGBTQI), les personnes vivant avec le VIH et les personnes ayant une expérience de travail du sexe — ainsi que leurs intersections. Nous mettons de l’avant une conception politique, sensible et intersectionnelle de la notion de communauté afin de dresser un portrait transversal des expériences de militance par le témoignage tout en relevant les singularités des points de vue qui la composent. En guise de conclusion, nous dégageons les éléments qui permettent d’entrevoir ces militantes et militants et leurs prises de parole publiques comme le prolongement des interventions féministes du siècle dernier et comme lieu de nombreux défis épistémiques et de mobilisation.
La participation et l’action militante des comités de parents à travers l’évolution
sociohistorique des maisons de naissance québécoises
Authors: Lorrain Roxanne
Published: August 2017

L’article suivant examine la participation des usagères dans les maisons de
naissance du Québec en analysant son évolution sociohistorique, et ce, du point de vue des
comités de parents. Il s’appuie sur une recherche qualitative menée auprès de femmes membres
de comités de parents pour comprendre comment les groupes militants s’organisent et
développent des moyens d’action concrets, novateurs, adaptés à leur réalité et répondant aux
besoins de leur collectivité. Cet article propose de situer la problématique à l’étude en
abordant les contextes historique, politique, juridique et institutionnel, ainsi qu’en
présentant la pratique sage-femme. Les résultats de recherche, analysés selon un cadre
conceptuel de la participation, permettent d’identifier le désir des femmes de s’engager
dans une maternité respectée, pour elles-mêmes et leur collectivité, de dégager une
typologie des comités de parents et de leurs activités, de cerner les défis rencontrés et
les stratégies déployées par les usagères et, enfin, d’aborder leurs perspectives sur leur
participation au sein des comités.
RNA helicase domains of viral origin in proteins of insect retrotransposons: possible source for evolutionary advantages
Authors: Morozov Sergey Y. , Lazareva Ekaterina A. , Solovyev Andrey G.
Published: August 2017

Recently, a novel phenomenon of horizontal gene transfer of helicase-encoding sequence from positive-stranded RNA viruses to LINE transposons in insect genomes was described. TRAS family transposons encoding an ORF2 protein, which comprised all typical functional domains and an additional helicase domain, were found to be preserved in many families during the evolution of the order Lepidoptera. In the present paper, in species of orders Hemiptera and Orthoptera, we found helicase domain-encoding sequences integrated into ORF1 of retrotransposons of the Jockey family. RNA helicases encoded by transposons of TRAS and Jockey families represented separate brunches in a phylogenetic tree of helicase domains and thus could be considered as independently originated in the evolution of insect transposons. Transcriptome database analyses revealed that both TRAS and Jockey transposons encoding the helicase domain represented transcribed genome sequences. Moreover, the transposon-encoded helicases were found to contain the full set of conserved motifs essential for their enzymatic activities. Taking into account the previously reported ability of RNA helicase encoded by TRAS ORF2 to suppress post-transcriptional RNA silencing, we propose possible scenarios of evolutionary fixation of actively expressed functional helicases of viral origin in insect retrotransposons as genetic elements advantageous for both transposons and their insect hosts.
Molting cycle and reproduction in the population of the shrimp Pleoticus muelleri (Crustacea, Penaeoidea) from Mar del Plata
Authors: Díaz AC , Petriella AM , Fenucci JL
Published: August 2017

The relationship between the molting cycle and gonadal maturation was investigated in the Pleoticus muelleri population from coastal waters of Mar del Plata, Argentina. The analysis of the molting activity revealed activity patterns that vary conspicuously with both the changes in shrimp reproductive status and the season. Males and females exhibited a molt synchronism and the intermolt lengthened during the reproductive season. Intermolt and early premolt females presented ripe ovaries, but in late premolt females, ovaries were in resorbed condition. The reproductive activity begins in spring and extends until autumn, with the maximum of impregnated females in summer. Ovarian development from immature to ripe was rapid in spring and summer, probably due to the increase in temperature and photophase. The potentiality of impregnation is independent of the size of females at least 6 g in weight. The large quantity of reserves and food needed for oocyte development was evidenced by the increment of the gonadosomatic index during maturation. Females showed higher hepatopancreatic indexes than males, which could be related to the high energetic requirement.
Structure by size, sex and maturity stage of the withe croaker (Micropogonias furnieri, Desmarest, 1823; Teleostei: Sciaenidae) in the bycatch of the artisanal fishery at Rocha Lagoon, Uruguay
Authors: Saona G , Forni F , Vizziano D , Norbis W
Published: August 2017

The structure of the population of white croaker (Micropogonias furnieri), a bycatch species of the multi-specific artisanal fishery at the coastal lagoon of Rocha, was analyzed. This species is Uruguay's second fishery resource and it has been declared fully exploited. Few data are available on the artisanal fishery and the biology of this fish, which inhabits the Uruguayan coastal lagoons. The white croakers were obtained from the bycatch of five fisheries that target diverse species in different parts of the lagoon. The five net types studied (mesh sizes 1, 2, 4, 10 and 20 cm) caught different fractions of the structure per size, sex and maturity stage. Both the median and first quartile of the size composition retained by each net size were bigger than the size at first maturity. This work shows the effect of different kinds of artisanal fishery on the structure of the white croaker population and provides basic information for the conservation and management of one of the fishery resources whose habitat forms part of the national park within the MAB/UNESCO Bañados del Este Biosphere Reserve.
Multiscale characterization of the sea temperature in an area of abalone banks (Haliotis spp.) at Bahia Asuncion, Baja California Sur, Mexico
Authors: Ponce-Díaz G , Lluch-Cota SE , Bautista-Romero JJ , Lluch-Belda D
Published: August 2017

The Baja California abalone is one of the most important Mexican fisheries because of its high economic value. Despite strong management efforts, this fishery has faced dramatic fluctuations attributed mainly to overfishing and variability of the marine climate. In this report we analyze sea temperature variability off Bahía Asunción, Baja California Sur (Mexico), at temporal scales that may affect abalone biological processes, such as mortality, reproduction, recruitment, and individual growth rate. Since the analysis is based on different data sources, we conducted a series of correlation analyses to determine the coherence between them. We report the average daily cycle and its variations throughout the year and between years for the period 1997–2000, the seasonal cycle and interannual deviations for the period 1992–2000, the behavior of the decadal scale variability based on annual values for the period 1959–1997, and the long-term trends after analyzing the entire 20th century. Furthermore, we conducted a spectral density analysis to estimate the proportional contribution of each temporal scale to the entire variability signal. Results from the high-frequency variability (daily to interannual) suggest a relationship between temperature and the abalone reproductive cycles, a potential negative effect of the very strong ENSO events on the postlarvae, and a differential effect of temperature on juveniles of different species. Regarding the low-frequency variability (decadal to century), we show that recent years represent a much warmer period compared to previous decades, suggesting a different biological community structure between periods. The spectral density analysis indicates seasonal variability as the major contributor to the regional variability, followed by the interannual (related to ENSO). There is almost no information of the marine climate in this region, particularly in regard to fine and high-resolution observations. This contribution will provide new quantitative elements for studies dealing with the ecology of these coastal productive systems.
Evolution and extension of the Santa Ana winds of February 2002 over the ocean, off California and the Baja California Peninsula
Authors: Castro R , Parés-Sierra A , Marinone SG
Published: August 2017

The evolution and extension of Santa Ana winds over the Pacific Ocean, off the coasts of California and the Baja California Peninsula, is documented from QuikScat satellite observations. The typical wind pattern in this region is towards the southeast, but between 9 and 12 February 2002 it was modified by Santa Ana winds, changing in direction towards the south, southwest and west. The changes were notable at first in southern California, but the largest indices of variation occurred between 26ºN and 28ºN off the Baja California Peninsula, with maxima in the Gulf of California, mainly in the northern part. The maximum extension of the winds to the west of the coast was on 11 February, reaching 32ºN and 125ºW, or ~700 km; however, towards the southwest the winds extended to 25ºN and 124ºW, or ~1000 km. The topography of the peninsula plays an important role in controlling the winds passing from the Gulf of California to the Pacific, causing plumes of sand and dust in several locations over the ocean.
Persistent organic pollutants in sediment cores from the southern region of the Bight of the Californias
Authors: Partida-Gutiérrez DI , Villaescusa JA , Macías-Zamora JV , Castillón FF
Published: August 2017

In January 1998, four sediment cores were collected to reconstruct the history of contamination by persistent organic compounds in the southern region of the Bight of the Californias. Two groups of compounds were determined using chromatographic methods: petroleum hydrocarbons (aliphatic hydrocarbons, AHs, and polynuclear aromatic hydrocarbons, PAHs) and chlorinated hydrocarbons (pesticides and polychlorinated biphenyls, PCBs). The AHs had low concentrations, from 0.30 to 3.38 µg g–1, and presented a biogenic allocthonous origin. The PAH concentrations ranged from 0.99 to 673 ng g–1. The distribution of the alkyl homologues and the compound indices showed a clear predominance of PAHs of petrogenic origin. The chlorinated hydrocarbons presented a surface maximum, decreasing with depth to non-detectable levels. The PCB concentrations ranged from 0.18 to 7.15 ng g–1 and pesticides from 0.09 to 19.71 ng g–1. The pesticides that occurred most frequently were p,p'-DDT and its metabolites (p,p'-DDE and p,p'-DDD). Other pesticides detected were γ-chlordane and BHC isomers (α and γ). The statigraphy of the cores was carried out with molecular markers (chlorinated hydrocarbons), which were used to calculate a rate of sedimentation of 0.17 to 0.55 cm yr–1.
Iridium: An option for measurement of the redox potential
Authors: Rios-Mendoza LM , Macias-Zamora JV , Zirino-Weiss AR
Published: August 2017

Some relevant results are presented of research leading to an alternative redox electrode to platinum. Several different electrodes were subjected to experiments under controlled conditions, mainly in artificial seawater. Among those tested were platinum, graphite, glassy carbon, gold and iridium. Our results, when combined with those estimated by using a model based on the MINEQL+ program, suggest that the O2/H2O2 redox couple is the one that controls the redox potential under these experimental conditions. In well-oxygenated waters (PO2 = 0.21 atm) and pH = 8, the value calculated for EH = 0.748 V and the pE at the surface should read 12.67 (pE = (F/2.3RT) EH = 12.67). However, in practice, the redox potential experimentally measured was only between +0.45 and +0.50 V. Additionally, the presence of H2O2 was determined from our own measurements. Its concentration was estimated at about 10–8 M. This value is in good agreement with values measured and reported by other authors for surface waters under natural conditions. The four sets of measurements that were carried out were: measurements where the O2 concentration of the solution was changed and the pH was kept constant (and vice versa); measurements of several redox couples (including Fe2+/Fe3+, NO3–/NO2– and I3–/I–); measurements in mud flats at San Quintín, Baja California; and measurement of the redox potential in natural seawater and in filtered and UV seawater. Most measurements indicate that the electrode with a response closest to that predicted by thermodynamics is the Ir electrode. We also found that the reaction of Pt, when compared to Ir, appeared to be slow.
Tidal transport of inorganic carbon and nutrients in a coastal salt marsh (Bay of Cádiz, SW Spain)
Authors: Forja JM , Ortega T , Ponce R , De-la-Paz M , Rubio JA , Gómez-Parra A.
Published: August 2017

The Bay of Cádiz is surrounded by a broad zone of salt marshes that exchange water through a seawater channel 18 km in length (the Sancti Petri Channel). These littoral zones are characterized by their extreme shallowness (with a mean depth of less than 1 m) and their high content of organic matter, which in relative terms is highest in the surface sediments (between 1.2% and 2.6% organic carbon). Under these conditions, an intensive benthic regeneration of nutrients takes place, with mean fluxes in the zone of 83.2 ± 36.9 mmol m–2 d–1 of inorganic carbon, 6.36 ± 4.56 mmol m–2 d–1 of NH4+, 1.14 ± 0.56 mmol m–2 d–1 of HPO4 2– and 4.54 ± 2.25 mmol m–2 d–1 of SiO2. A proportion of these nutrients and inorganic carbon produced make their way through secondary channels to the Sancti Petri Channel, and the material is later transported by the tides to the Bay of Cádiz and other bordering littoral zones. In this work, the concentrations of inorganic carbon and nutrients (NH4+, NO2–, NO3–, HPO42– and SiO2) have been determined at three different depths, every hour, during complete tidal cycles. Simultaneously, the current velocities at different depths have been measured continuously. From this set of experimental data, calculations have been made of the evolution of the instantaneous velocities of these substances at each end of the channel, and by integration, the net balance for the complete tidal cycle. In general terms, there is an export of inorganic carbon and nutrients with the tides, although the net transports are very variable and depend to a large extent on the hydrodynamics of the zone. The results obtained correlate with balances previously made in the Bay of Cádiz.
Evidence for concentration of anthropogenic mercury in salt marsh sediments
Authors: Micaelo C , Válega M , Vale C , Pereira E , Duarte A , Caçador I
Published: August 2017

Sediment cores from two salt marshes, Rosário (Tagus estuary) and Laranjo (Ria de Aveiro), were analyzed for total Hg and Al, and for Fe and Mn extracted with a hydroxylamine-acetic acid solution. Both areas have been contaminated by industrial discharges during the last decades. Vertical distributions of Hg in sediments colonized by Arthrocnemum fruticosum and Halimione portulacoides were compared to profiles in non-vegetated sediments. The same vertical distribution pattern was observed in all situations: Hg enriched in sediment layers with high root density. Mercury concentrations reached 9.3 and 29.1 nmol g–1 in Rosário, and 149.0 and 196.0 nmol g–1 in Laranjo. At both marshes, higher concentrations were found in sediments colonized by H. portulacoides. These values are one order of magnitude above the levels found in nonvegetated sediments. Mercury was enriched in sediment layers containing high concentrations of Fe extracted with a hydroxylamine-acetic acid solution, indicating the importance of Fe (and Mn) oxides formed in the rooting sediments for the retention of anthropogenic Hg.
A comparative study of the adsorption of linear alkylbenzene sulfonates and their biodegradation intermediates on marine sediments and organisms
Authors: Sáez M , León VM , Rubio JA , Gómez-Parra A , González-Mazo E
Published: August 2017

Linear alkylbenzene sulfonate (LAS) and sulfophenylcarboxylate acid (SPC) adsorption on suspended material (sediment and phytoplankton) has been determined in laboratory experiments. The kinetic characterization of the adsorption process allows the time to the steady state to be established, which was 12 and 18 hours for LAS and SPC, respectively. Organic carbon normalized coefficients for sediment and lipid content normalized coefficients for microalgae are similar for each compound, showing a clear trend with its non-polar character. Therefore, the highest coefficients correspond to LAS (8 × 103). A clear tendency was observed for the species of alga: Nannochloropsis gaditana had higher partition coefficientes for both LAS and SPC than Dunaliella salina.
Chemical speciation of dissolved lead in polluted environments. A case of study: the Pontevedra Ria (NW Spain)
Authors: Cobelo-García A , Prego R , Nieto O
Published: August 2017

Chemical speciation of dissolved lead was determined at four sampling sites in the Pontevedra Ría (NW Spain) by differential pulse anodic stripping voltammetry (DPASV) with a HMDE. Sampling location was chosen due to its evident anthropogenic influence: one sample was taken in the Lérez River mouth (2.2-salinity) and other three samples were taken in the surroundings of the village of Marín (salinity 30–32). Lead concentrations were 0.64 nM (river sample) and 4.8–21.9 nM (saline samples). Speciation results showed that organic chelates of lead, 88–95% of total dissolved lead, are the dominant species of the metal even at these high concentrations. Two types of lead organic complexing ligands were detected in all samples. The river water sample showed the presence of a strong ligand with a concentration of ~7 nM with a conditional stability constant of K'Pb-L1 ≥ 1011.1, and a weaker ligand (K'Pb-L2 = 108.2) with a concentration of 53.4 nM. The three saline samples showed similar behavior: a strong ligand (K'Pb-L1 ~ 108.6) with concentration ranging from 33.0 to 53.5 nM, and a weaker complexing ligand (K'Pb-L2 ~ 107.5) with concentration ranging from 32.6 to 50.5 nM. All lead-organic ligand complexes (except the strong complex in the river water sample) showed labile behavior in the time scale of the technique.
The taxonomic status of Porites sverdrupi, an endemic coral of the Gulf of California
Authors: López-Pérez RA , Reyes-Bonilla H , Budd AF , Correa-Sandoval F
Published: August 2017

Porites sverdrupi has long been considered to be an ecotype of the more abundant and widespread species P. panamensis, but multivariate comparisons of corallite characteristics indicate that P. sverdrupi is morphologically distinct and thus represents a valid species. In these analyses, linear measurements and counts were made on 72 colonies of the two species (53 of P. panamensis and 19 of P. sverdrupi), and analyzed multivariately using canonical discriminant analysis. Generally, corallite characteristics of P. sverdrupi are larger in size than P. panamensis. Important characters in the discriminant function (e.g., number of bifurcate septa, wall thickness, and dorsal septum length) have not been recognized in previous studies of Porites in either the Indo-Pacific or Atlantic regions as being significant in distinguishing among poritid species. In addition to corallite characteristics, P. sverdrupi is unique in its ecological habit, colony form, and geographic distribution.
Effect of the seaweed Macrocystis pyrifera and a formulated diet on growth and fatty acid composition in the green abalone, Haliotis fulgens, under commercial culture conditions
Authors: Durazo-Beltrán E , Toro-Vázquez JF , Vásquez-Peláez C , Viana MT
Published: August 2017

The effect of a formulated diet (FD), a seaweed diet (SW), and a mixture of both (FD + SW) on growth, survival rate, and fatty acid content in the tissue of juvenile Haliotis fulgens abalone grown under commercial culture conditions, was analyzed over a 329-day period. Survival and growth rate in terms of length and weight were different with each of the diets evaluated, being significantly higher (P < 0.05) with the mixed diet (FD + SW), followed by SW and FD. Since feed intake was not evaluated in this preliminary study, differences in growth cannot be attributed to the dietary treatments; however, the importance of this work was to show the significant impact of the diet treatments on the tissue fatty acid profiles, suggesting that the treatments contribute to the composition of some fatty acids found in muscle. The polyunsaturated fatty acid (PUFA) 22:4n-6 was not detected in any of the diets, while 20:4n-3 was only present in SW and 22:5n-3 only in FD. However, after the feeding experiment all these PUFAs were present in abalone tissue. The possible synthesis of PUFAs from dietary n-3 and n-6 fatty acids of shorter hydrocarbon chain is discussed.
Modern sands of the Gulf of Mexico: Discriminating fluvial and coastal sand composition
Authors: Kasper-Zubillaga JJ , Carranza-Edwards A
Published: August 2017

A forward stepwise linear discriminant analysis, A-Nova test and R-mode factor analysis were used on modern beach, dune and river sands to discriminate the geographic distribution of detrital modes between sands sourced by volcanic rocks (Trans-Mexican Volcanic Belt (TMVB) sands) and sedimentary rocks (Veracruz Embayment (VE) sands). Thirty-three beach, dune and river sand samples were collected across beach-dune profiles, in the inner reaches of the channel and at the river mouth during the dry season. The source terranes for these sands are constituted by Miocene to Pliocene volcanites and by Tertiary to Quaternary siliciclastic rocks. To avoid the constrained character of compositional data, point-count percentages were expressed as compositional modal Log ratios (i.e., Log Qt/Ft = total quartz/total feldspars, Log Qt/Lt = total quartz/total lithics, Log Ft/Lt = total feldspars/total lithics, Log Qm/Fk = monocrystalline quartz/potash feldspars, Log Qm/Fp = monocrystalline quartz/ plagioclase, Log Fk/Fp = potash feldspars/plagioclase, and Log Lv/Ls = volcanic lithics/sedimentary lithics). The linear discriminant and factor analyses showed that the geographical dispersal of detrital modes between the TMVB sands and VE sands are statistically significant by means of the Log Lv/Ls, Log Qt/Ft, Log Qt/Lt and Log Ft/Lt ratios. The A-Nova test and post-hoc analyses showed that the mean differences of the Log Lv/Ls, Log Qt/Ft and Log Qt/Lt ratios are highly significant for the VE river sands and the TMVB dune sands. The composition of the TMVB dune sands is controlled by a longshore drift of quartz supply. The VE river sands are depleted in Ls due to the mechanical and/or chemical weathering of Ls and the influence of TMVB on the composition of the VE river sands.
Soil heat exchange in Puerto Cuatreros tidal flats, Argentina
Authors: Beigt D , Píccolo MC , Perillo GM
Published: August 2017

Some interaction processes at the sediment-water and sediment-atmosphere interfaces were analyzed for each season of the year using mass aerodynamic formulas. Data were collected from Puerto Cuatreros tidal flats (Bahía Blanca estuary, Argentina) during an entire year (2000). The soil temperature was measured every 10 min by a thermistor chain at three levels below the sediment surface (–0.05, –0.15 and –0.25 m). Water and air temperatures, solar radiation and meteorological data were registered simultaneously, resulting in annual means of 14.07ºC (soil at –0.15 m), 13.69ºC (air) and 14.51ºC (water). Atmospheric and tidal conditions regulated the mudflat's thermal behavior. The soil temperature vertical profiles showed a diurnal and semidiurnal cycle due to the influence of these factors. The diurnal thermal amplitude at –0.05 m reached 14.6ºC on 20 February 2000, but only 2.8ºC on 1 July 2000. Most fluctuations of sediment temperatures were observed in the first 15 cm, with vertical gradients of 0.82ºC cm–1 during summer. In order to obtain the soil heat capacity, the granulometric composition of a sediment column was analyzed. Soil heat fluxes during a typical summer and winter day were compared. A net heat gain in the soil was observed during the summer day (+840.6 kJ m–2) and an inverse situation was found in winter, with a diurnal heat exchange of –768.6 kJ m–2.
Effect of dietary protein level and commercial feeds on growth and feeding of juvenile common snook, Centropomus undecimalis (Bloch, 1792)
Authors: Gracia-López V , García-Galano T , Gaxiola-Cortés G , Pacheco-Campos J
Published: August 2017

Preliminary results of the effects of different dietary protein levels and commercial feeds on growth and feeding of juvenile common snook, Centropomus undecimalis (Bloch, 1792), were obtained under controlled laboratory conditions in two experiments. In the first experiment (60 days), juveniles (initially 2.9 g) maintained at 26.6ºC were fed one of four isocaloric experimental diets containing different protein levels (diet A = 28.8%, diet B = 40.4%, diet C = 53.4%, and diet D = 65.8%). Shrimp-, soybean-, and fish-meal were used as protein sources. Best growth, specific growth rate, and feed conversion ratio were obtained with diets B, C, and D. There were no significant differences (P > 0.05) among these three treatments. Protein efficiency ratio decreased as the level of dietary protein increased and was highest for fish fed diet A. In the second experiment (65 days), the effects of three different commercial pellets (for tilapia, catfish, and trout) and diet C were determined on snook (initially 22.7 g) at 29.1ºC. There was no significant difference in fish weight gain between diet C and trout pellets. Significantly higher (P < 0.05) weight gain was achieved with diet C and trout pellets compared with that of fish fed the tilapia and catfish pellets. Specific growth rate and feed conversion ratio were best with diet C, and significant differences among all treatments were obtained. Protein efficiency ratio for fish fed diet C and trout and tilapia feeds was not significantly different. The results confirm the snook's ability to feed on pellets, its capability to adapt to dry feeds, the potential of commercial feeds for raising snook, and its relatively high dietary protein requirement.
Biochemical characterization of the eelgrass Zostera marina at its southern distribution limit in the North Pacific
Authors: Cabello-Pasini A , Muñoz-Salazar R , Ward DH
Published: August 2017

The eelgrass Zostera marina L. is distributed along the Baja California Peninsula (Mexico) where it is exposed to a wide range of irradiances and temperatures that could promote changes in its biochemical composition. Consequently, the objective of this study was to characterize the variations in the levels of chlorophyll, carbohydrates, proteins, fiber, ash and calories in the shoots of Z. marina from the north (San Quintín) and south (Ojo de Liebre and San Ignacio lagoons) of the peninsula. Temperature in the southern lagoons was 5–6ºC higher than in the northern lagoon; likewise, in situ irradiance was two-fold greater in the south than in the north. As a result of the lower irradiance levels, the concentration of chlorophyll in the shoots of Z. marina was twice as high (1.7 mg gWW–1) in the northern lagoon than in the southern ones (0.8 mg gWW–1). Similar to chlorophyll levels, the concentration of soluble carbohydrates in the shoots was greater in the northern lagoon than in the southern ones, suggesting that the high levels of chlorophyll are enough to compensate for the low irradiance levels and to maintain a positive carbon balance at San Quintín. On the other hand, the levels of proteins in the shoots from the north of the peninsula were slightly lower than those from the southern populations. In general, these results suggest that the different environmental conditions to which Z. marina is exposed along the peninsula impact its biochemical composition.
Lower Cretaceous Alisitos Formation at Punta San Isidro: Coastal sedimentation and volcanism
Authors: Payne JL , Jhonson ME , Ledesma-Vázquez J
Published: August 2017

The Lower Cretaceous (Aptian-Albian) Alisitos Formation is well exposed at Punta San Isidro and adjacent sea cliffs on the Pacific shores of Baja California near Eréndira, Mexico. Continuous coastal outcrops define a local stratigraphic succession less than 100 m in total thickness, including repetitious tuff, sandstone and conglomerate units interbedded with discontinuous limestone beds rarely more than 2.5 m thick. The limestone beds are biostromal units that include scattered oysters and/or corals, as well as units dominated by the rudistid bivalve, Caprinuloidea perfecta. Two distinctive conglomerate units are composed of andesite cobbles colonized by encrusting oysters in a quasi rocky-shore setting. One sandstone unit includes abundant fossil wood with tree limbs up to 55 cm long and 5 cm in diameter. Proximal volcanic activity is indicated by a series of dikes that cut through pyroclastic beds and lead to a 10-m thick andesitic flow that caps the succession at Punta San Isidro. Compared with thicker intervals of the Alisitos Formation elsewhere in Baja California that are dominated by andesitic flows and offshore limestone, the Punta San Isidro sequence offers a window on a back-reef environment adjacent to a paleoshore that received pyroclastic lahars from a terrestrial origin or mass flows from shallow submarine explosions. Recovery of marine life and the renewal of a carbonate substrate followed successive episodes of volcanism and massive erosion along an active coastline. This scenario is very different from depositional processes of the Upper Cretaceous (Campanian-Maastrichtian) Rosario Formation that cannibalized and subsequently formed a regional unconformity against tilted Alisitos strata with substantial topographic relief in the Eréndira region.
A technique for the separation of the most recently deposited nacreous layer in Mytilus californianus shells for trace metal analysis
Authors: Rivero LE , Lares ML
Published: August 2017

A new method to separate a section of the most recently deposited nacreous layer from the rest of the shell of Mytilus californianus was developed. Techniques described for other mussel species proved unsuitable for this species. In this new method, the shells are soaked in 30% hydrogen peroxide for 10–15 min at 80–85ºC to eliminate the periostracum, a potential source of trace metal contamination. Next, the shells are heated in a muffle furnace at 350ºC for 1 h to separate the nacreous layer from the calcite layer. Finally, the nacreous band is easily separated from the rest of the shell by gently tapping it with a stainless steel needle. This is a simple and fast method that is proposed for trace metal monitoring purposes using M. californianus shells. To illustrate the application of the method, results from an experiment performed in our laboratory, in which mussels were exposed to two different Cd concentrations for 60 days and their shells processed by this technique, are included. The most recently deposited nacreous layer showed significant increases in Cd concentrations, which were proportional to the exposed ambient concentrations.
Relationship between the thermal vertical structure of Cuban waters and tropical cyclone activity
Authors: Mitrani-Arenal I , Díaz-Rodríguez OO
Published: August 2017

A study of the oceanic surface layer is presented, taking into account its vertical thermal structure and time-space variability. Oceanographic data from 37 cruises were used. The thickness of the isothermal layer and depth of the 26ºC isotherm were determined. The possible connection between the thermal characteristics of the sea surface layer and tropical cyclone activity was analyzed. The presence of ENSO was considered. We show that the thermal characteristics of Cuban waters are always favorable for tropical cyclone development.
Heavy metals in the clam Tivela mactroides Born, 1778 (Bivalvia: Veneridae) from coastal localities with different degrees of contamination in Venezuela
Authors: Acosta V , Lodeiros C
Published: August 2017

We compared heavy metal levels (manganese, iron, zinc, cadmium, copper, chromium, and lead) in tissues and shells of juveniles (13±2.2 mm), medium-size organisms with mature gonads (25±4.1mm), and adults (35±1.2 mm) of the clam Tivela mactroides from three different locations along the Venezuelan coast: Playa Güiria, on the northeastern coast, was not affected by environmental pollution, but Río Chico and Boca de Paparo, influenced by the Tuy River on the central coast, were. Heavy metal concentrations were related to shell size, with significant differences among populations and shell sizes. Specimens from Boca de Paparo and Río Chico had the highest heavy metal concentrations in tissues and shells, in contrast with the levels found in specimens from Playa Güiria, in which chromium and lead were absent. The high heavy metal concentrations found in tissues from specimens collected at Boca de Paparo and Río Chico were possibly of anthropogenic origin and generated by the Tuy River. The environmental conditions at Boca de Paparo may have favored the bioaccumulation of most heavy metals in specimen tissues. At Playa Güiria, however, the heavy metal concentrations were found to be within a natural range. Our results show that T. mactroides is a good biological indicator of the presence of heavy metals in the littoral waters they inhabit.
Hormone induced spawning (HCG), and embryonic and larval development of the leopard grouper, Mycteroperca rosacea (Streets, 1877)
Authors: Gracia-López V , Rodríguez-Romero J , Pérez-Ramírez JM
Published: August 2017

Induced spawning of two wild females of the leopard grouper, Mycteroperca rosacea, was obtained using Human Chorionic Gonadotropin (HCG) supplied in two dosages: a first injection of 1000 IU/kg and a second of 500 IU/kg, 24 h apart. Of the four treated females, two had a positive spawning response, releasing approximately 40,000 eggs/fish. These were fertilized with mature male sperm. The fertilization rate obtained for each female was 10% and 0%. Complete embryonic development, and the morphology of eggs and larvae are described until the first feeding. Eggs were spherical, buoyant and transparent, with a diameter of 872.8 ±15.4 ∞m (ranging from 850.4 to 912.5 ∞m) and an oil droplet diameter of 177.3 ± 7.0 ∞m.
High-Sensitivity Cardiac Troponin T Reporting, Clinical Outcomes, and Health Care Resource Use
Authors: Nguyen Mau T. , Lambrakis Kristina , Lehman Sam , Haustead Daniel , Psaltis Peter J. , Chew Derek P. , Papendick Cynthia
Published: October 2024

Importance

Despite being recommended by clinical guidelines, substantial concerns remain regarding the use of high-sensitivity cardiac troponin assays and whether it is associated with increased resource use, myocardial infarction (MI) or myocardial injury diagnoses, and procedural rates.

Objective

To characterize the association of reporting high-sensitivity cardiac troponin T (hs-cTnT) to the lowest limit of quantification vs conventional troponin reporting with clinical outcomes.

Design, Setting, and Participants

This cohort study used a historically controlled baseline and follow-up design to compare clinical outcomes after changing hs-cTnT reporting to the lowest limit of quantification. All patients aged 18 years or older presenting to any public emergency department (ED) in the state of South Australia between February 1, 2020, and February 28, 2021, who had an hs-cTnT test in the 6 months before and after the change in troponin reporting practice were included. Outcomes were assessed after adjusting for patient characteristics using inverse probability treatment weighting. The data analysis was performed between May 1, 2022, and July 27, 2023.

Exposure

hs-cTcnT reporting.

Main Outcomes and Measures

The main outcomes were frequency of diagnosed MI, coronary angiography, percutaneous coronary intervention, and coronary artery bypass graft (CABG); hospital length of stay; and ED discharge rate as measured using time-to-event Cox regression models. The secondary outcome was the composite 12-month event rate of all-cause mortality, MI, and myocardial injury.

Results

A total of 40 921 patients were included, of whom 20 206 were included in the unmasked hs-cTnT reporting group (median [IQR] age, 62.0 [46.0-77.0]; 10 120 females [50.1%]) and 20 715 were included in the conventional troponin reporting group (median [IQR] age, 63.0 [47.0-77.0] years; 10 752 males [51.9%]). Unmasked hs-cTnT reporting was associated with higher ED discharge rates (45.2% vs 39.0%; P < .001) and a shorter median hospital length of stay (7.68 [IQR, 4.32-46.80] hours vs 7.92 [IQR, 4.56-49.92] hours; P < .001). There was no difference in diagnosis of MI, coronary angiography, percutaneous coronary intervention, or coronary artery bypass graft. The composite of all-cause mortality, MI, and myocardial injury at 12 months was similar (adjusted hazard ratio, 0.95; 95% CI, 0.90-1.01; P = .09).

Conclusions and Relevance

This cohort study found that unrestricted reporting of hs-cTnT results to the lowest limit of quantification was not associated with an increase in the diagnosis of MI, invasive coronary procedures, or harm at 12 months but may be associated with improved hospital resource use.
Influence of Positive/Negative Emotions Towards Autobiographical Memories on Impressions of the Conversation and Conversation Partner During Nostalgic Memory Sharing
Authors: Sugimori Eriko , Kusumi Takashi
Published: October 2024

We investigated the effects of positive/negative emotions towards autobiographical memories on impressions of the conversation and conversation partner during memory sharing in a reminiscence therapy setting. Fifty‐six older (Mage = 69.3) and 60 younger (Mage = 20.7) participants' net emotional tendency (positive/negative) towards autobiographical memories and depressive symptoms were evaluated using validated rating scales. Positive/positive and positive/negative age‐matched random pairs shared a nostalgic memory through free conversation. Participants with a negative emotional tendency towards autobiographical memories in positive/negative pairs tended to feel less “easy” about the conversation. Participants with a positive emotional tendency towards autobiographical memories in positive/negative pairs had a more negative impression of their partners. Our data provide insight into the relationship between net emotional tendency towards autobiographical memories and depression and suggest that an individual's net emotional tendency towards autobiographical memories potentially affects the outcome of group reminiscence therapy.
Phase Heterojunction by Constructing Built‐In Electric Field toward Sodium‐Rich Cathode Material
Authors: Lai Qingsong , Liu Chen , Gao Xuan‐Wen , Liu Zhaomeng , Yang Dongrun , Nie Zhen , Li Wei , Gu Qinfen , Luo Wen‐Bin
Published: October 2024

An artificial built‐in electric field from phase heterojunction is constructed within sodium‐rich manganese‐based layer‐structured oxide O3‐Na[Ni0.3Mn0.55Cu0.1Ti0.05]O2@Na2MoO4 through shared oxygen atoms. The spinel Na2MoO4 phase behaves as a p‐type semiconductor, while the O3‐Na[Ni0.3Mn0.55Cu0.1Ti0.05]O2 phase functions as an n‐type semiconductor. It can efficiently reduce the diffusion barrier and enhance electron transport, which can adequately promote the interfacial desolvation ability and reduce bulk lattice strains. The formed spinel heterostructure with crystal structure stability can also enhance the interface Na+ diffusion and protect the electrode against moisture and carbon dioxide corrosion. Besides, the molybdenum introduction within the lattice bulk can enhance the bond covalency, fortifying lattice oxygen stability and restraining structural distortion effectively. The obtained cathode demonstrates a high up to 224.61 mAh g−1 discharge specific capacity at 0.1 C and a long cycle stability with a 60.44% capacity retention after 265 cycles at 0.5 C. This study illuminates the potential of Na‐rich Mn‐based oxide cathodes for high‐energy‐density sodium battery utilizations.
Insights into Photothermocatalytic Dry Reforming of Methane on Ru/La‐Al2O3 using Carbonate Species and Reactive Oxygen Species to Enhance the Fuel Production Rates and Completely Prevent Coking
Authors: Cao Huamin , Li Yuanzhi , Wu Jichun , Zhong Mengqi , Ji Lei
Published: October 2024

Photothermocatalytic dry reforming of methane (DRM) offers a promising strategy for converting solar energy into fuel. However, the high light intensity required for high fuel production rates and thermodynamically more favorable coking side reactions limit this strategy. Herein, a nanocomposite of La‐doped Al2O3 supporting Ru nanoparticles (NPs) (Ru/La‐Al2O3) is synthesized. At relatively low light intensity (80.2 kW m−2), Ru/La‐Al2O3 obtains high production rates of CO and H2 per gram of Ru (rRu, CO and rRu, H2, 8410.19 and 7181.94 mmol gRu−1 min−1) with light‐to‐fuel efficiency (η, 26.6%), and completely prohibits coking. In striking contrast, the reference catalyst without La doping (Ru/Al2O3) exhibits lower rRu, CO, rRu, H2, η and produces large amounts of coke. The improved photothermocatalytic performance stems from the fact that reactive oxygen species and carbonate species are involved in the oxidation of carbon species (rate‐determining steps of DRM) through two different reaction pathways, which significantly increases catalytic activity and prevents the carbon species from polymerizing into coke. Additionally, light not only enhances the DRM on Ru NPs and the oxidation reaction between carbonate species and carbon species but also promotes the dissociation of CH4 and desorption of H2, which improves the catalytic activity and product selectivity of Ru/La‐Al2O3.
The Role of Hydrogen in ReRAM
Authors: Cox Horatio R. J. , Sharpe Matthew K. , McAleese Callum , Laitinen Mikko , Dulai Jeevan , Smith Richard , England Jonathan , Ng Wing H. , Buckwell Mark , Zhao Longfei , Fearn Sarah , Mehonic Adnan , Kenyon Anthony J.
Published: October 2024

Previous research on transistor gate oxides reveals a clear link between hydrogen content and oxide breakdown. This has implications for redox‐based resistive random access memory (ReRAM) devices, which exploit soft, reversible, dielectric breakdown, as hydrogen is often not considered in modeling or measured experimentally. Here quantitative measurements, corroborated across multiple techniques are reported, that reveal ReRAM devices, whether manufactured in a university setting or research foundry, contain concentrations of hydrogen at levels likely to impact resistance switching behavior. To the knowledge this is the first empirical measurement depth profiling hydrogen concentration through a ReRAM device. Applying a recently‐developed Secondary Ion Mass Spectrometry analysis technique enables to measure hydrogen diffusion across the interfaces of SiOx ReRAM devices as a result of operation. These techniques can be applied to a broad range of devices to further understand ReRAM operation. Careful control of temperatures, precursors, and exposure to ambient during fabrication should limit hydrogen concentration. Additionally, using thin oxynitride or TiO2 capping layers should prevent diffusion of hydrogen and other contaminants into devices during operation. Applying these principles to ReRAM devices will enable considerable, informed, improvements in performance.
Chiral Inorganic Nanomaterials Characterized by Advanced TEM: A Qualitative and Quantitative Study
Authors: Chen Jiaqi , Chen Xuegang , Murakami Ri‐Ichi , Li Hanbo , Yu Xue , Feng Wei , Yang Yuxin , Wang Pan , Zheng Guangchao , Tang Zhiyong , Wu Xiaochun
Published: October 2024

Chiral inorganic nanomaterials (CINMs) have garnered significant interest due to their exceptional optical, electronic, and catalytic properties, offering promising advancements in energy conversion, data storage, catalysis, and biomedicine. While traditional optical spectrophotometers reveal the chiroptical performance of CINMs on an ensemble level, the direct structural visualization for the qualitative and quantitative discernment of their chiral features has become increasingly distinct with the advancements of transmission electron microscopy (TEM) techniques. The need for reasonable and high‐standard discrimination requirements of CINMs has driven the progress of chirality‐based TEM technologies. Therefore, this review in the good season takes the initiative to summarize the current advancements in TEM technologies for CINMs characterization, emphasizing a qualitative analysis of chiral atomic‐level features, 0D, 1D, and 2D nanocrystals, and assembled nanomaterials. Then, the quantitative methods for determining chirality is also highlighted, such as 3D electron tomography, and further address the evolution of chiral structures monitored by the Ex‐situ and In‐situ TEM technologies. By providing a roadmap for the current challenges and proposing future advancements in TEM technologies for the qualitative, quantitative, and real‐time analysis of CINMs, it can drive innovations in the field of chiral nanomaterials as well as the development of TEM technologies.