Water Interchange Research Articles

Análisis de las instalaciones de agua con riesgo de legionelosis en la Costa del Sol, Málaga, España

En España, durante la última década, ha aumentado el interés por el mantenimiento higiénico-preventivo para el control microbiológico en las instalaciones de agua. Con objeto de obtener una óptima calidad en los parámetros de las instalaciones de intercambio aire-agua, se han desarrollado protocolos de tratamiento y normativa al efecto. Diversas investigaciones han puesto de manifiesto la existencia del agente biológico Legionella pneumophila. El estudio aborda la aplicación de métodos de mantenimiento preventivo con objeto de controlar el desarrollo de la bacteria. Se investigó una muestra de las instalaciones de agua correspondientes a edificios públicos de la Costa del Sol, Málaga (España), mediante 83 variables, análisis cluster y de correspondencias. Los resultados incluyen un análisis detallado de la aplicación de métodos de control de la calidad del agua según los tipos de edificios. Se concluye con el grado de cumplimiento en el mantenimiento y la importancia según la tipología.

Quantitative Analysis of the Water Occupancy around the Selectivity Filter of a K+ Channel in Different Gating Modes

Recovery in K(+) channels, that is, the transition from the inactivated nonconductive selectivity filter conformation toward the conductive conformation, occurs on a time scale of the order of seconds, which is astonishingly long, given that the structural differences among the filter conformations are faint (<1 Å). Computational studies and electrophysiological measurements suggested that buried water molecules bound behind the selectivity filter are at the origin of the slowness of recovery in K(+) channels. Using a combination of solid-state NMR spectroscopy (ssNMR) and long molecular dynamics simulations, we sketch a high-resolution map of the spatial and temporal distribution of water behind the selectivity filter of a membrane-embedded K(+) channel in two different gating modes. Our study demonstrates that buried water molecules with long residence times are spread all along the rear of the inactivated filter, which explains the recovery kinetics. In contrast, the same region of the structure appears to be dewetted when the selectivity filter is in the conductive state. Using proton-detected ssNMR on fully protonated channels, we demonstrate the presence of a pathway that allows for the interchange of buried and bulk water, as required for a functional influence of buried water on recovery and slow inactivation. Furthermore, we provide direct experimental evidence for the presence of additional ordered water molecules that surround the filter and that are modulated by the channel's gating mode.

Excess protons in water-acetone mixtures. II. A conductivity study

In the present work we complement a previous simulation study [R. Semino and D. Laria, J. Chem. Phys. 136, 194503 (2012)] on the disruption of the proton transfer mechanism in water by the addition of an aprotic solvent, such as acetone. We provide experimental measurements of the mobility of protons in aqueous-acetone mixtures in a wide composition range, for water molar fractions, xw, between 0.05 and 1.00. Furthermore, new molecular dynamics simulation results are presented for rich acetone mixtures, which provide further insight into the proton transport mechanism in water-non-protic solvent mixtures. The proton mobility was analyzed between xw 0.05 and 1.00 and compared to molecular dynamics simulation data. Results show two qualitative changes in the proton transport composition dependence at xw ∼ 0.25 and 0.8. At xw < 0.25 the ratio of the infinite dilution molar conductivities of HCl and LiCl, Λ(0)(HCl).Λ(0)(LiCl)(-1), is approximately constant and equal to one, since the proton diffusion is vehicular and equal to that of Li(+). At xw ∼ 0.25, proton mobility starts to differ from that of Li(+) indicating that above this concentration the Grotthuss transport mechanism starts to be possible. Molecular dynamics simulation results showed that at this threshold concentration the probability of interconversion between two Eigen structures starts to be non-negligible. At xw ∼ 0.8, the infinite molar conductivity of HCl concentration dependence qualitatively changes. This result is in excellent agreement with the analysis presented in the previous simulation work and it has been ascribed to the interchange of water and acetone molecules in the second solvation shell of the hydronium ion.

Waterbirds and human-related threats to their conservation in Laguna Cuyutlán, Colima, México

Laguna Cuyutlán, the only large wetland in a span of 1,150 km along the Pacific coast of Mexico, has been neglected as to its importance for waterbird conservation. At least 25 waterbird species nest there, with some of their colonies being very relevant, and at least 61 waterbird species use the lagoon during their non-breeding season. This lagoon has been subject to several structural modifications, including levees and artificial channels which connect it to the sea, while water supply from continental sources has diminished, although its role has not been assessed yet. Salt extraction and artisanal fishery, the main economic activities, do not seem to pose a threat to waterbirds. Among potential threats to this acquatic ecosystem, are the raw sewage discharges that exist near urban areas, and pesticides from the surrounding agricultural lands might reach the lagoon. Seemingly, the most serious threat comes from waterway development in connection with a re-gasification plant to be built, and planned future port expansion, which could potentially increase water levels and alter important habitats for nesting and foraging. We recommend that: the area be declared an Important Bird Area; the development of the re-gasification plant and future port includes a levee to prevent alterations in water level in the remaining sections of the lagoon; supply of exogenous chemicals and waste products be prevented and monitored; alleged benefits from water interchange between the lagoon and the sea through artificial channels should be re-evaluated; and the role of fresh water supplies to the lagoon should be paid attention to.

Experimental study on the performance characteristics of porous perpendicular pipe breakwaters

Several investigations of the physical properties of wave–structure interactions and absorption of structures in coastal areas discussed the development of several permeable and porous breakwaters. This article addresses highly-pervious dense pipe with small apertures, which can be beneficial for convection and interchange of sea water within the harbor district, and furthermore, perform effectively in wave absorption. This study investigates the dissipation of porous perpendicular pipe breakwaters, and presents laboratory investigations of wave transmission from permeable pipe breakwaters with different wave conditions and various combinations of diameter and tube length. Since wave energy is mainly dissipated due to drag and interception of the resultant motion by the pipe breakwaters, the reflectivity of such effects is discussed by the evaluation of partly reflected and transmitted ratio. Consequently, the performance of the pipe breakwater for predicting the wave transmission coefficient is investigated. Experimental results reveal that dissipation and/or reflection is more effective when decreasing pipe diameter than increasing pipe length, specifically when dimensionless frequency σ2h/g>1.5. Nevertheless, the effect is relatively inconspicuous when σ2h/g<0.75. A partial outcome demonstrates the influence of pipe diameter and variations of reflection coefficients corresponding with dimensionless frequencies for incident waves with various wave heights.

Wet-on-Wet Padding for Energy Conservation

We report a reconstitution method which could provide consistent shade depth and add-on in wet-on-wet pad/batch dyeing and finishing. Textile wet processing involves many steps of wetting and drying. Eliminating some of them by the wet-on-wet process could save energy. For a continuous process, due to the fast fabric movement, a wet fabric also could enhance chemical penetration for the improvement of properties and savings on auxiliary chemicals. One common problem associated with wet-on-wet process is that after padding several hundred yards of yarns/fabrics, chemical add-on is considerably decreased, resulting in the decreased shade depth or performance of the finished goods. This phenomenon is the result of water interchange in the chemical pad. Once the water interchange rate is obtained, quality of wet-on-wet finished materials could be controlled.

Looking for efficiency through integrated water management between agriculture and urban uses

Many urban water systems must cope with water scarcity and climate change and additionally they must be able to fulfil the objectives of environmental protection, efficiency and sustainability. At the end they must provide the expected level of service now and in the future horizons. Some new comprehensive approaches are assessing the total water footprint in a territory using the concept of virtual water and incorporating interactions between agriculture, urban and industrial uses. Besides this broader method of analysis it is important to go further and make analysis of opportunities for efficiency based on a new paradigm of integrated use of water. Investing in improvement of efficiency not only in urban distribution systems, studying the possibilities of permanent or temporal reallocation of water rights from agriculture to urban. Establishing agreements for interchange of raw water for urban regenerated water. Signing options contracts for water trading under drought conditions. Risk of shortage is the factor to complete the framework and it is a key component to review and to manage

Building up Nanotubes: Docking of “Janus” Cyclodextrins in Solution

Using molecular dynamics experiments, we analyze the association of "Janus" 6-amino-6-deoxy-2O-carboxymethyl-beta-cyclodextrins (JCD) in aqueous solutions. In JCD dimers, the free energy associated with the primary-rim-secondary-rim docking shows a stable minimum of approximately -45 kcal mol(-1). Trimers in solution are also remarkably stable, exhibiting minimal distortions in their spatial and orientational distributions. The resulting geometrical docking shows the incipient characteristics of flexible nanotubes in solution, with eventual water interchange between the central channel and the bulk at the junctions between monomers. Structural and dynamical properties of the trapped water filling the nanotube are dictated to a large extent by the charge density at the rims.

Analysis and Evaluation of Depth of Frozen Ground Affected by Road Climatic Conditions

Climatic factors are divided into more equable and more variable. More variable factors include a multi-year weather regime of a particular region or country. Climatic information, based on which climatic parameters and various quantitative indicators are calculated, is obtained from diferent sources. Primary meteorological information is the data obtained during the observations in meteorological stations. Another meteorological information especially important for road design, construction, and maintenance is obtained from the Road Weather Information System (RWIS). Lithuania belongs to a number of countries experiencing a large effect of climatic conditions on road design, construction, and repair. Climatic conditions are the amplitude and speed of temperature variation, temperature max and min, precipitation, wind direction and speed, thickness of snow cover, and depth of such ground. One of the most important climatic factors in winter is a frozen ground. The depth of such ground depends on a negative temperature and its stability, thickness of snow cover, and the start of its formation, vegetation, soil properties, and composition. The action of frost changes the structure of soil and affects the surface and underground water interchange. Therefore, investigations and analysis of the change in the depth of frozen ground is important from both the theoretical and practical point of view.

Changes in continental ostracode shell chemistry; uncertainty of cause

Ostracode shell chemistry is a powerful tool for recording changes of certain dissolved ions in their environment. Such data are commonly interpreted in terms of change in temperature and salinity, which are then used to offer insights into paleohydrology and from that paleoclimate. In particular, the changes in Sr/Cashell are believed to reflect changes in salinity, and the changes in Mg/Cashell to reflect both salinity and water temperature. However, the established application of this proxy too often ignores the complexities involved in the chemical changes accompanying solute evolution, hydrologic change, physical chemistry, and the autoecology and biology of ostracodes. Chemical changes occur: (1) in the dissolved Mg/Ca and Sr/Ca ratios during solute evolution, (2) as a consequence of multiple sources of water, but especially ground and surface water interchange as well as evaporation, (3) as a consequence of different dissolved cation–anion pair formation at various concentrations, and (4) because of bio/ecologic effects, including seasonality of molting and taxa-specific ionic regulation capabilities. We suggest that changes in shell chemistry in a stratigraphic sequence tell us when changes occurred in the solutes, but cannot identify what caused those change(s) in the chemical environment. Inclusion of information from other paleoenvironmental and paleoclimatic proxies that co-occur with ostracode shells may help to limit the choices amongst possible causes.

Binuclear manganese(II) complexes in biological systems

The paper reports calculations on binuclear manganese(II) clusters related to those found in biological systems. B3LYP/6-311g(d,p) density functional theory (DFT) calculations are carried out specifically on a set of clusters that derive from the X-ray crystal structure of DNA polymerase β [Batra, V. K. et al., Structure 14, 757–766 (2006)]. Issues investigated are: (a) the relative energy of the lowest and highest spin states (antiferromagnetic (low spin/broken symmetry = LS/BS) or ferromagnetic); (b) the Mn(II)–Mn(II) distance; (c) the effect of water versus CH3OH (a sugar analogue) as a direct Mn ligand; and (d) the effect of the kind of oxygen bridge (mono-oxygen, single-oxygen from a carboxylate or phosphate, or a two-oxygen bridge from a carboxylate), on the geometry and energy. It was found generally that the antiferromagnetic state is lower in energy, that the Mn(II)–Mn(II) distance (which varies from 2.91 to 3.57 Å in the series studied) is longer for ferromagnetic states than for the corresponding low spin states, that the interchange of CH3OH and water does not affect the results, and that a single (carboxylate) oxygen as bridge leads to a lower energy than a corresponding two (carboxylate) oxygen bridge, as well as to a more compact structure.

Microhermal nodules of Renalcis-like calcimicrobes from Oxfordian limestones of the Sierra Madre Oriental (Novillo Formation, Mexico)

Microhermal nodules very similar to those from the Oxfordian Smackover Formation are volumetrically important constituents of the Novillo Formation exposed in eastern Central Mexico. The nodules occur within a micritic limestone succession (Novillo Limestone). Coalescence of adjacent nodules leads to a delicate self-supported frame. Microhermal nodules consist of both microbial carbonate and clustered digitate and branching chambered microfossils. The latter occur in the form of crust-like agglomerations or bushy growth habit in small growth-framework cavities created by accretionary microbialites. Main growth patterns are branching upward, downward facing and pendant. Like Renalcis, the microfossils apparently resulted from the activity of calcimicrobes. Terebella, encrusting foraminifers, and Tubiphytes form part of the microhermal biota and occur as subordinate faunal components. The association developed on the floor of a calm, shallow-marine lagoon with restricted water interchange and reduced oxygenation at the sediment–water interface.

Larval fish assemblages and geostrophic circulation in Bahía de La Paz and the surrounding southwestern region of the Gulf of California

We analyze spatial-temporal relationship between larval fish assemblages and geostrophic surface flow in Bahia de La Paz and the neighboring Gulf of California (May, July and October 2001 and February 2002). The analysis of fish larvae distribution in relation to geostrophic circulation and hydrography is an innovative interdisciplinary approach for the understanding of fish larvae ecology. The Bray-Curtis Index defined two larval fish assemblages with spatial-temporal variations: coastal assemblage dominated by epipelagic coastal species (e.g. Sardinops caeruleus) and oceanic assemblages-oceanic and transitional oceanic assemblages both dominated by mesopelagic species (e.g. Vinciguerria lucetia and Benthosema panamense) but with different larval abundance. The assemblage variations appear to be related to water exchange between the bay and the Gulf through the North Mouth. During July-October, the geostrophic flow through the entrance is strong, and the oceanic assemblages spread in the whole bay, whereas during February-May when the geostrophic transport is weak, the coastal assemblage is distributed over the whole bay. The strong summer-autumn water interchange between bay and gulf is in agreement with the annual evolution of the surface water properties inside the bay, from high-salinity Gulf of California Water during winter-spring to fresher Tropical Surface Water during summer-autumn, when the highest species number was recorded.

The sedimentation of salmonid spawning gravels in the Hampshire Avon catchment, UK: implications for the dissolved oxygen content of intragravel water and embryo survival

AbstractThe accumulation of sediment within salmonid redd gravels can have a detrimental impact on the development of salmonid embryos; therefore, redd sedimentation represents a potential limiting factor for salmonid reproduction. The links between redd sedimentation, the dissolved oxygen content of intragravel water and salmonid embryo survival within the upper and middle parts of the Hampshire Avon catchment in southern England are explored. Measurements of surface and intragravel water quality and redd properties were undertaken for artificial redds constructed at known spawning sites. Salmonid embryos were also planted into artificial redds adjacent to the monitoring equipment. The rate of sedimentation of the newly cleaned redd gravels demonstrated a non‐linear decrease over time, which is attributed to a particle‐size‐selective depositional process. The results of the study confirm that low embryo survival and low dissolved oxygen concentrations in intragravel water can be attributed to the accumulation of sediment within the redd gravels. This was found to produce a reduction in redd permeability, which limited the interchange of surface and intragravel water and, therefore, the supply of dissolved oxygen to the intragravel environment. In view of the diminished status of salmonids within many of the UK's chalk rivers and streams, the results highlight the need for management initiatives aimed at reducing redd sedimentation and thereby optimizing salmonid embryo incubation success. Copyright © 2006 John Wiley &amp; Sons, Ltd.

Hydrographic variability in Bahia De La Paz, B. C. S, Mexico, during the 1997–1998 El Niño

Abstract Bahia de La Paz is an integral part of the coast of the Gulf of California and is the biggest bay of the eastern side of the Baja California Peninsula. Dynamic forcing and water interchange occur between the bay and the gulf through two different openings, the main and deep North Mouth with 350-m depth and the shallow San Lorenzo Channel with an average depth of 10 m. To determine the oceanographic conditions before and during El Nino 1997–1998 in Bahia de La Paz, CTD data were collected in four surveys aboard the research yacht CICIMAR XV during July 1996, March 1997, July 1997, and March 1998. The results revealed important variations in the hydrographic structure of the bay, both in space and time. The two summers had a complete absence of the mixed layer with a sharper thermocline during summer 1996 (0.25°C/m) than in summer 1997 (0.21°C/m). Additionally, the entire water column experienced an average temperature increase from 1.5°C at the surface with a maximum of 4.2°C to 28 m and around 1°C between 100 and 350 m, showing a halocline structure in summer 1997. At the end of the winters of 1997 and 1998, a 50-m mixed layer was detected, with higher average temperatures of 2.3°C in winter 1998. The temperature differences decreased with depth and were the same at 340 m with no traces of the halocline in winter 1998. The increase of temperature observed in the study area during the periods affected by El Nino 1997–1998 resulted in a sinking of the thermocline and isotherms, showing the strongest effect of this warming (>4°C) in the surface layer to 70 m during summer 1997. The stratification increased during the El Nino and was more evident in the period of small stratification in the region (winter) as showed by the φ parameter with values of 45 J/m 3 in 1998 and 29 J/m 3 in 1997, whereas during the strong stratification period (summer) the difference was small, with values of 137 J/m 3 in 1996 and 139 J/m 3 in 1997. In periods not affected by El Nino, the Gulf of California and the Subtropical Subsurface Waters are usually present in the bay, but during this episode their presence varies in space. Additionally, Surface Equatorial Water was found in the bay, mainly at the end of winter 1998 and with some traces in summer 1997.

Black Sea–Marmara Sea Quaternary connections: new data from the Bosphorus, İstanbul, Turkey

Previous studies concluded that the Bosphorus Strait was formed during the Quaternary by fluvial incision of a valley between the Black Sea, to the north, and the Marmara Sea in the south. Hitherto, however, few details of the evolution of this connection have been elucidated from the sediments deposited within the Bosphorus itself. We report here details of sedimentological and palaeontological evidence relating to this history, obtained from five boreholes drilled into the unconsolidated sediment fill in the north-central sector of the Bosphorus, together with nearby geophysical profiles. The Quaternary fill of this part of the Bosphorus comprises two major facies associations. Yellow arkosic sands dominate the lower Facies Association A: these are assigned a Middle to Late Pleistocene age and the contained faunas have a lagoonal to lacustrine character and a Black Sea provenance (Paratethyan affinities). The abruptly succeeding units of Facies Association B comprise fining and coarsening upwards units of coarse to fine shelly and clayey sands that alternate with shell-bearing green clays. These sediments were formed in a range of marine and coastal settings and biostratigraphic evidence and absolute dating demonstrate the Mid–Late Holocene age of this upper unit. Initially brackish faunal assemblages in this upper unit show an upward increase in marine and Mediterranean affinities. Integrating these new data with previously published observations from coeval deposits in the southern Bosphorus and İzmıt Bay (NE Marmara Sea) we conclude that during the Late Pleistocene and Early Holocene a topographic barrier existed in the south-central sector of the Bosphorus, on both sides of which estuarine and lagoonal sediments accumulated, with distinctive Black Sea and Mediterranean faunas. During a significant rise in sea level, between 7000 and 5300 years ago, this barrier was finally submerged, permitting interchange of marine waters between the Mediterranean and the Black Sea and creating the present oceanographic situation. This evolution conflicts with the cataclysmic role of the Bosphorus in the early Holocene as postulated in the ‘Catastrophic Flood’ hypothesis of Ryan et al. [Mar. Geol. 138 (1997) 119–126; Annu. Rev. Earth Planet. Sci. 31 (2003) 525–554]. It also contrasts with the history recorded from the Gulf of İzmıt, where intermittent connection between these two bodies of water throughout much of the Quaternary is evident.

Structural analysis of nine-coordinate lanthanide complexes: steric control of the metal-water distance across the series.

The structures of 10 isomorphous lanthanide (Ln) complexes of a chiral DOTA tetra-amide ligand (L(1)), [LnL(1)(H(2)O)](CF(3)SO(3))(3).3H(2)O, crystallizing in space group P2(1), have been studied by single-crystal X-ray diffraction. The Ln coordination is a O(4)N(4) square antiprism, the O(4) base of which is capped by an aqua ligand. The sterically demanding position of the latter results in the lengthening of the Ln-OH(2) distance along the Pr to Lu series by 0.06 A (after allowing for the lanthanide contraction). In parallel, the distance between the bound water oxygen and the second-sphere water oxygen is reduced from 3.17 A (Pr) to 3.04 A (Lu), consistent with the enhanced hydrogen bond acceptor ability of the coordinated water oxygen across the series. A Cambridge Structural Database survey of [Ln(H(2)O)(9)](CF(3)SO(3))(3) salts (space group P6(3)/m) and of six reported isostructural complexes of DOTA [L(2)] revealed a similar trend. The implications of the resultant destabilization of the ground state structure for the water interchange process are discussed.

Estabilidad de las aguas del Pacífico colombiano - mayo 2000

The calculations of stability, considering the Criterion of Hesselberg-Svedrup and Frequency of Brunt Vaisala are made by means of temperatura and salinity obtained from the monitoring to the study area in May 2000 The resulte were analyzed with profiles of stability (with its thermal and saline componente) and of frequency. The stability, is also analyzed in different layers from the study area: 0-10, 10-25, 25-50, 50-75, 75-100 and 100-150m. The results show that in may 2000, the máximum values of stability in the Colombian Pacific appear in zones with greater possibility of water interchange with different termohalyns properties, which sees in the North sector and the Northwest (warm waters from Panama) in layer 10-25 mand, in the coast zone in layer 0-10 m. The vertical structure of temperatura in the study area is very variable and, therefore, this one is the more influences in its stability. The greater frequencies were observed in the South sector of the zones near the coast. The smaller frequencies were observed in the central, South and southwestern sector of the riverine basin of Colombian Pacific.

A Computational Environment for Water Flow along Floodplains

A numerical model for the computer simulation of large floodplain inundations is presented. The model is extremely simple in order to achieve efficient computations in regions greater than 1000 km 2 . It is based on raster Digital Elevation Models (DEMs) and rules for water interchange between neighbor cells. The computer implementation, AQUA code, includes facilities for interpolation of precipitation data, graphics visualization and interactive DEM modification for simulation of alternative scenarios. The numerical performance was analyzed in some simple cases and the model was applied to a 1600 km 2 landscape corresponding to the region of Pehuajo in Argentina, which experiences frequent floodings.

Characterisation of reused osmotic solution as ingredient in new product formulation

Osmotic dehydration (OD) with sugar solutions has been used in fruit preservation but part of the process's economic viability depends on the possibility of reusing the osmotic solution (OS) in successive dehydration cycles. Despite the increase in water content, OD promotes OS enrichment in certain water-soluble natural components extracted from fruits, such as vitamins and minerals. For this reason, to recycle it for new food formulation seems to be an attractive alternative. In this paper, changes in soluble solids, a w, pH, electrical conductivity, density, viscosity and colour in osmotic solution used for kiwifruit dehydration in function of the ratio osmotic solution/fruit (20:1, 10:1 and 5:1) and the number of cycles (up to 10) have been studied. Microbiological analysis of OS and fruit compositional changes were also studied. The results show that during OD likewise water interchange between fruit and OS, a flow of mineral salts and sugar from the fruit to the OS, is produced. Nevertheless OS changes associated to the OD of kiwifruit under the conditions of this study allow OS reuse for at least 10 cycles without any problems related to fruit dehydration level, colour fruit changes, or considerable microbiological contamination.