Correction to: Water masses in the Caribbean Sea and sub‑annual variability in the Guajira upwelling region     

Torres  Rafael Ricardo  Latandret  Sadid  Salon  Jhon  Dagua  Claudia 《Ocean Dynamics》2023,73(9):593-593

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A multicatchment analysis of headwater and downstream temperature effects from contemporary forest harvesting          下载免费PDF全文

Kevin D. Bladon  Catalina Segura  Nicholas A. Cook  Sharon Bywater‐Reyes  Maryanne Reiter 《水文研究》2018,32(2):293-304

Stream temperature is a key physical water‐quality parameter, controlling many biological, chemical, and physical processes in aquatic ecosystems. Maintenance of cool stream temperatures during summer is critical for high‐quality aquatic habitat. As such, transmission of warm water from small, nonfish‐bearing headwater streams after forest harvesting could cause warming in downstream fish‐bearing stream reaches with negative consequences. In this study, we evaluate (a) the effects of contemporary forest management practices on stream temperature in small, headwater streams, (b) the transmission of thermal signals from headwater reaches after harvesting to downstream fish‐bearing reaches, and (c) the relative role of lithology and forest management practices in influencing differential thermal responses in both the headwater and downstream reaches. We measured summer stream temperatures both preharvest and postharvest at 29 sites—12 upstream sites (4 reference, 8 harvested) and 17 downstream sites (5 reference, 12 harvested)—across 3 paired watershed studies in western Oregon. The 7‐day moving average of daily maximum stream temperature (T_7DAYMAX) was greater during the postharvest period relative to the preharvest period at 7 of the 8 harvested upstream sites. Although the T_7DAYMAX was generally warmer in the downstream direction at most of the stream reaches during both the preharvest and postharvest period, there was no evidence for additional downstream warming related to the harvesting activity. Rather, the T_7DAYMAX cooled rapidly as stream water flowed into forested reaches ~370–1,420 m downstream of harvested areas. Finally, the magnitude of effects of contemporary forest management practices on stream temperature increased with the proportion of catchment underlain by more resistant lithology at both the headwater and downstream sites, reducing the potential for the cooling influence of groundwater.  相似文献   

Sampling uncertainties and source <Emphasis Type="Italic">b</Emphasis> likelihood for the Gutenberg-Richter <Emphasis Type="Italic">b</Emphasis> value from the Aki-Utsu method     

F. A. Nava  L. Ávila-Barrientos  V. H. Márquez-Ramírez  I. Torres  F. R. Zúñiga 《Journal of Seismology》2018,22(1):315-324

The Aki-Utsu method of Gutenberg-Richter (G-R) b value estimation is often misapplied so that estimations not using the G-R histogram are often meaningless because they are not based on adequate samples. We propose a method to estimate the likelihood Pr(b?b _m , N, M ₁, M ₂) that an observed b _m estimate, based on a sample of N magnitudes within an [M ₁????≤?ΔM/2,?M ₂?+?ΔM/2) range, where ΔM?=?0.1 is the usual rounding applied to magnitudes, is due to a “true” source b value, b, and use these likelihoods to estimate source b ranges corresponding to various confidence levels. As an example of application of the method, we estimate the b values before and after the occurrence of a 7.4-magnitude earthquake in the Mexican subduction zone, and find a difference of 0.82 between them with 100% confidence that the b values are different.  相似文献   

Revisiting tropical instability wave variability in the Atlantic ocean using SODA reanalysis     

Hatsue Takanaca de Decco  Audalio Rebelo Torres Junior  Luciano Ponzi Pezzi  Luiz Landau 《Ocean Dynamics》2018,68(3):327-345

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Removal of Pyridine from Aqueous Solution by Adsorption on an Activated Carbon Cloth     

Pedro Alonso‐Davila  Oliva L. Torres‐Rivera  Roberto Leyva‐Ramos  Raul Ocampo‐Perez 《洁净——土壤、空气、水》2012,40(1):45-53

Pyridine is a very toxic pollutant that has to be removed from wastewater. In this work, adsorption of pyridine on activated carbon cloth (ACC) is studied as a possible alternative for eliminating pyridine from aqueous solution. The ACC was produced from polyacrylonitrile. The adsorption equilibrium data of pyridine on ACC was obtained in a batch adsorber. The experimental data was interpreted with the isotherms of Langmuir, Freundlich, and Prausnitz‐Radke (PR), and the PR isotherm better represented the experimental data. The capacity of ACC for adsorbing pyridine was favored increasing the solution pH from 3 to 6, and this effect was due to the π–π dispersive and electrostatic interactions between the pyridine species in solution and the surface complexes of ACC. The modified Langmuir model fitted reasonably well the influence of pH on the adsorption capacity. In this model was assumed that both neutral pyridine and pyridinium were simultaneously adsorbed on ACC accordingly to the experimental results. The adsorption capacity was almost independent of temperature. The reversibility study revealed that 75% of the pyridine can be desorbed from ACC indicating that part of the pyridine was irreversibly adsorbed, and possibly chemisorbed.  相似文献   

Coral communities and reefs from Guerrero,Southern Mexican Pacific     

Ramón A. López‐Pérez  Luis E. Calderón‐Aguilera  Héctor Reyes‐Bonilla  José D. Carriquiry  Pedro Medina‐Rosas  Amilcar L. Cupul‐Magaña  María D. Herrero‐Pérezrul  Héctor A. Hernández‐Ramírez  Miguel Á. Ahumada‐Sempoal  Betsabe M. Luna‐Salguero 《Marine Ecology》2012,33(4):407-416

Corals in the Eastern Pacific extend south from the Gulf of California to Ecuador and oceanic Chile, and west from Colombia to Clipperton Atoll. Nevertheless, large stretches of the Mexican Pacific remain fundamentally unstudied. Therefore, to assess the current conditions of coral communities, a coastal fringe ～300 km long (17°40′ N, 101°39′ W to 16°46′ N, 99°49′ W) was surveyed within the Southern Mexican Pacific, between 2005 and 2009. Fifteen stony coral species were identified at 13 coral communities and six Pocillopora‐dominated fringing reefs, with Pocillopora verrucosa and Pocillopora damicornis the primary contributing taxa. Reef development was identified in embayments or behind rocks or islands that offered shelter from northern and northwestern winds. Observations of Pocillopora effusus, Pocillopora inflata, Porites lobata, Pavona clavus, and Pavona varians expanded the species known geographic ranges by several degrees of latitude, suggesting reef building fauna comprised a mixture of widespread and relatively rare Eastern Pacific corals. Results indicated greater live coral cover in the Ixtapa‐Zihuatanejo area (15–73%) than in the Acapulco localities, which had high algal dominance; the reefs in the latter region exhibited high erosion. Regional differences are likely the result of long‐standing anthropogenic pressures around Acapulco since 1950, when it became an important tourist destination. This paper is the first detailed report of ecologically stressed corals and coral reefs from the state of Guerrero on the Mexican Southern Pacific coast.  相似文献   

Sky luminance distribution in Pamplona (Spain) during the summer period     

J.L. Torres  M. de Blas  A. García  A. Gracia  A. de Francisco 《Journal of Atmospheric and Solar》2010,72(5-6):382-388

In this work the outdoor daylight conditions in Pamplona (South Europe) during the summer period have been studied. The selected sky type (from fifteen standards) at a given moment is the one exhibiting the lowest RMSD when comparing the theoretical and experimental luminance distributions in the sky hemisphere. Two year data of luminance distribution registered every 10 min in 145 positions of the sky hemisphere have been used for selecting the sky type. The most frequent sky type in Pamplona is V.5 (cloudless polluted with a broad solar corona), with an occurrence of 29.5%. This result coincides with the one observed in a previous study in Athens.Six types of sky (V.5, IV.4, III.4, III.3, V.4 y II.2) out of the fifteen standards become practically the 80% of all the studied ones. Regarding a possible use in daylight climate studies, the frequency of occurrence of the fifteen types of sky for fourteen solar elevation intervals has been included.  相似文献   

Undocumented Students’ Narratives of Liminal Citizenship: High Aspirations,Exclusion, and “In-Between” Identities     

Rebecca Maria Torres  Melissa Wicks-Asbun 《The Professional geographer》2013,65(2):195-204

This study illustrates how national immigration policy relegates undocumented immigrant children to spaces of liminal citizenship, which shape their aspirations for higher education. Recognizing the power of migrant narratives, and the importance of privileging youths’ voices through children's geographies, we present the narratives of undocumented high school students from several rural North Carolina communities. Despite various barriers facing undocumented students, most have high academic aspirations. Students construct new forms of citizenship, legitimating their claims to higher education access through their achievement. Their liminal status, however, contributes to the formation of conflicted, “in-between” identities.  相似文献   

Total mercury in terrestrial systems (air-soil-plant-water) at the mining region of San Joaquín,Queretaro, Mexico     

Sergio Martínez-Trinidad  Gilberto Hernández Silva  Juventino Martínez Reyes  Gregorio Solorio Munguía  Sara Solís Valdez  Martha Elena Ramírez Islas  Rocío García Martínez 《Geofísica Internacional》2013,52(1):43-58

Deficient management of cinnabar mining left the San Joaquín region with high concentrations of mercury in its soils (2.4 – 4164 mg kg^-1). Numerous cinnabar mines have contributed to the dispersion of mercury into agricultural (0.5 –314 mg kg^-1) and forest (0.2 – 69 mg kg^-1) soils. Sediments are a natural means of transportation for mercury, causing its spreading, especially in areas near mine entrances (0.6 – 687 mg kg^-1). The nearness of maize crops to mines favors mercury accumulation in the different plant structures, such as roots, stems, leaves, and grain (0.04 – 8.2 mg kg^-1); these being related to mercury volatilization and accumulation in soils. Mercury vapor present in the settlements could indicate a constant volatilization from lands and soils (22 – 153 ng m^-3). The mercury levels found in the soils, in maize grain, and in the air resulted greater than the standards reported by the Official Mexican Norm (NOM) and the World Health Organization (WHO). Mercury in rainwater is due mainly to the presence of suspended atmospheric particles, later deposited on the surface (1.5 – 339 μg |^-1). Mercury dissolution was found in the drinking water (10 – 170 ng |^-1), with concentrations below those established by the NOM and the WHO. The contamination existing in the San Joaquín region does not reach the levels of the world’s greatest mercury producers: Almaden (Spain) and Idrija (Slovenia). It is, however, like that found in other important second degree world producers such as Guizhou (China). The population of San Joaquín, as well as its surrounding environment, are constantly exposed to mercury contamination, thus making a long term monitoring necessary to determine its effects, especially to people.  相似文献   

Uranium-series isotopes transport in surface,vadose and ground waters at San Marcos uranium bearing basin,Chihuahua, Mexico     

Juan Carlos Burillo Montúfar  Manuel Reyes Cortés  Ignacio Alfonso Reyes Cortés  Ma. Socorro Espino Valdez  Octavio Raúl Hinojosa de la Garza  Diana Pamela Nevárez Ronquillo  Eduardo Herrera Peraza  Marusia Rentería Villalobos  María Elena Montero Cabrera 《Applied Geochemistry》2012

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