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Interactive effects of excess boron and salinity on histological and ultrastructural leaves of Zea mays amylacea from the Lluta Valley (Arica-Chile)

Interactive effects of excess boron and salinity on histological and ultrastructural leaves of Zea mays amylacea from the Lluta Valley (Arica-Chile)

showed a rigidification of the cell wall because the modulus of elasticity increased under saline conditions of 430 mM NaCl, but the increase was reversed by the addition of extra B (Bastías et al., 2004b). Many studies also suggested that reduced cell turgor potential and cell wall elasticity lead to the formation of small cells and intercellular spaces in salt-treated plants (Suarez et al., 1998). The invaginations of the plasma membrane have been described in response to saline and water stress (Serraj et al., 1995; Niu et al., 1996). In amylacea maize, the plasma membrane presented small cristae-like invaginations and was detached from the cell wall in several regions (Figure 2C), indicating an incipient plasmolysis that may be caused by excess ions or osmotic stress. This al- teration of the plasma membrane is in accordance with the increase in membrane permeability observed in this maize under high salinity con- ditions of 430 mM NaCl (Bastías et al., 2004b). Nevertheless, the structural damages observed by TEM in amylacea maize were less than those described in other maize and rice plants under saline conditions (Pareek et al., 1997). Recent evidence has demonstrated that the presence of apparent invaginations in the plasma membrane originated as a result of endosomal vesicles called plasmalemosomas. This presence of located mul- tivesicular bodies could correspond to a situation of relocalization of tonoplast aquaporins because they exhibit PIP-type aquaporin that would help the cell to maintain an osmotic balance between the cytoplasm and the vacuole under stress conditions. Alternatively, multivesicular bodies could mediate the specific solute uptake toward the vacuole to avoid direct contact between ions and cytoplasmic components (Kirch et al., 2000; Vera-Estrella et al., 2004).

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Ectoine bio milking in methanotrophs: A step further towards methane based bio refineries into high added value products

Ectoine bio milking in methanotrophs: A step further towards methane based bio refineries into high added value products

A fed-batch fermentation, consisting of three consecutive 50 h two-stage cultivations at 25 ºC and 600 rpm, was initially carried out in triplicate in sterile 1.2 L gas-tight reactors containing 300 mL of a mineral salt medium (MSM) specific for alkalophilic methanotrophs [16] and inoculated at 0.13 ± 0.01 g TSS L -1 (Table S1). The two-stage M. alcaliphilum 20Z cultivation involved an initial incubation at high salinity (6 % NaCl) for 24 hours to promote bacterial growth and ectoine accumulation followed by a biomass harvesting step and a final bacterial incubation for 24 hours in the absence of NaCl to promote the excretion of ectoine (TSI). Cells were harvested by centrifugation at 9000g for 10 min, washed twice with a 0.85 % NaCl solution and re-suspended in a NaCl free MSM prior cultivation in NaCl free MSM, while 80 mL of sterile 22.5 % NaCl MSM were added to the NaCl free MSM prior cultivation at 6 % in TS2 and 3. The headspace CH 4

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Ammonium enhances resistance to salinity stress in citrus plants

Ammonium enhances resistance to salinity stress in citrus plants

Furthermore, PHGPx gene expression levels have been recorded to increase in plant tissues in response to pathogen infections (Criqui et al., 1992), high salinity (Li et al., 2001), heavy metals (Li et al., 2001), and extreme temperatures (Chen et al., 2004), suggesting the important roles that play in the defense responses of plants to biotic and abiotic stresses. Transient expression of LePHGPx protects tobacco leaves from salt and heat stress, and suppresses the apoptotic pathway induced by Bax (Chen et al., 2004). Our results suggest that the resistance to salinity that we found in the N-NH 4 + -treated plants could be mediated by a

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Nonlinear allometric equation for crop response to soil salinity

Nonlinear allometric equation for crop response to soil salinity

Shabala, 2000; Zhang et al., 2012). Indeed, Munns and Tester (2008) summarized the characteristics of the osmotic and ionic effects, being the former fast and involved in the decrease of new growth, while the latter is slow and leads to the senescence of older leaves; according to them, at high salinity levels the ionic effect dominates over the osmotic effect. Moreover, Shabala (2000) concluded that the perception of the ionic and osmotic components of salt stress is probably associated to different ionic mechanisms. Recently, Zhang et al. (2012) confirmed these observations in a study on barley germination by which they determined in general that at low salinities the osmotic effect is mainly involved; at medium salinities the two effects act together, while at high salinities the ionic effect dominates the harmful action on the germination process. This sequence of observations indicates the gradual change from osmotic to ionic-dominated effects which should match, turning at the inflection point. Thus, evidence in the literature supports us in our proposition on the meaning and utility of the inflection point.

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Ecophysiological adaptability of tropical aquatic organisms to salinity changes [Spanish]

Ecophysiological adaptability of tropical aquatic organisms to salinity changes [Spanish]

Abstract: Physiological response of tropical organisms to salinity changes was studied for some marine, estu- arine and freshwater fishes (Astyanax bimaculatus, Petenia karussii, Cyprinodon dearborni, and Oreochromis mossambicus), marine and freshwater crustaceans (Penaeus brasiliensis, Penaeus schmitti and Macrobrachium carcinus), and marine bivalves (Perna perna, Crassostrea rhizophorae, and Arca zebra) collected from North- east Venezuela. They were acclimated for four weeks at various salinities, and (1) placed at high salinities to determine mean lethal salinity, (2) tested by increasing salinity 5 ‰ per day to define upper lethal salinity tol- erance limit, or (3) observed in a saline gradient tank to determine salinity preference. Acclimation level was the most significant factor. This phenomenon is important for tropical aquatic organisms in shallow waters, where they can adapt to high salinity during the dry season and cannot lose their acclimation level at low salinity dur- ing abrupt rain. For saline adaptation of tropical organisms, this behavior will contribute to their proliferation and distribution in fluctuating salinity environments.

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Phaseolus vulgaris response to salinity generated by NaCl, Na2SO4 and NaHCO3

Phaseolus vulgaris response to salinity generated by NaCl, Na2SO4 and NaHCO3

If the salt concentration of the growth medium exceeds the tolerance of the plant, the height, fresh and dry stem biomass and the water content in the plant would decrease (Cachorro et al., 1993; Hosseini et al., 2002; Bai et al., 2008; Keshavarzi, 2012; Habtamu et al., 2014). Some plants in order to tolerate high salinity levels in the growth medium perform an osmotic adjustment, which allows them to generate potentials smaller than the medium and to be able to absorb water and nutrients. Osmotic adjustment allows to maintain or increase cell turgor and plant growth (Bai et al., 2008; Bahena-Betancourt et al., 2008; Pratap and Sharma, 2010).

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http://www.epi.org/files/2013/ceo-pay-2012-extraordinarily-high.pdf

http://www.epi.org/files/2013/ceo-pay-2012-extraordinarily-high.pdf

CEO compensation has grown a great deal but so has pay of other high-wage earners. To some analysts this sug- gests that the dramatic rise in CEO compensation was driven largely by the demand for the skills of CEOs and other highly paid professionals. This interpretation, then, is that CEO compensation is being set by the market for “skills” and is taken as evidence that rising CEO com- pensation is not due to managerial power and rent-seek- ing behavior (Bebchuk and Fried, 2004). One prominent example of the “it’s other professions, too” argument comes from Kaplan (2012a, 2012b). For instance, in the prestigious 2012 Martin Feldstein Lecture, Kaplan claimed:

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Mutual feedback in e portfolio assessment: an approach to the netfolio system

Mutual feedback in e portfolio assessment: an approach to the netfolio system

learning that is more profound. However, although the final results are important, we prefer to ask what is inside the so-called ‘black box’. Following the work of Black and William (1998) who call attention to the dangers of understanding a class as a black box into which certain inputs are inserted and given outputs extracted, we aim to know more about what takes place inside the box. It is commonly recognised that formative evaluation is at the heart of high quality teaching and learning and that this evaluation must be, at the very least, consistent with the teaching methods. This, in the light of the emerging results, suggests that feedback between peers should not be an accidental practise, but an essential, integrated component of the evaluation system (in this case based on the e-portfolio methodology which is already, in itself, enough of a paradigm of formative evaluation). Within this framework, we observe that the role of the teacher alters and takes an unexpected direction. We already men- tioned that netfolio increases the student’s revisions, but, in relation to the teacher, another type of work is introduced. This teacher work is directed towards what could be called an ‘observant assessment’. The teacher does not provide more feedback in the development of the netfolio than in the classical e-portfolio but must bring together a more complex network of interactions between the students and intervene when necessary. This does not necessarily translate into a number of messages; it is rather a vigilant and silent observation of what goes on in the online class. The teacher is in the mutual assessments but does not intervene directly, and this non- intervention becomes a positive assent, ie, he or she reaffirms with a silent but con- stant presence (message read register) the resolution of the evaluator student in the sense that the work is being developed and assessed correctly. This point suggests that a greater development of IT tools is needed to help teachers and students to make this positive presence more explicit and visible as an indicator to ensure the correct devel- opment of the learning assignments. This kind of teaching demands technological and pedagogic adaptations to online teaching and learning environments that combine distance with closeness, the invaluable help of the teacher with the inescap- able responsibility of the student, that is to say, the promotion of a learning solution that is both shared and autonomous.

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Monitoreo de la humedad de suelo superficial a partir de observaciones satelitales de Microondas activas y pasivas

Monitoreo de la humedad de suelo superficial a partir de observaciones satelitales de Microondas activas y pasivas

Las estimaciones precisas de humedad de suelo superi- cial son cruciales en hidrología, micrometeorología y en la agricultura para la interpretación de los ciclos del agua y el carbono. Las comunidades cientíicas relacionadas con estas temáticas han mostrado la necesidad de una mejor comprensión de las diferentes fuentes naturales de agua, ya que este recurso tiene un impacto social crítico en la producción alimenticia. Es por ello que los cientíicos buscan el monitoreo de la humedad de suelo y contenido de agua en la vegetación a gran escala espacial y temporal (Monsiváis, et al., 2008). Debido a la extensa área de monitoreo, los sensores a bordo de saté- lites representan una herramienta muy útil. Los estudios recientes han demostrado que es posible obtener estima- ciones de suelo, independientemente de las condiciones meteorológicas, mediante observaciones satelitales con sensores que operan en el rango de frecuencias de las mi- croondas (longitudes de onda mayores a 1 mm) (Kustas, Zhan y Schmugge, 1998). En los estudios también se ha encontrado que los sensores, que operan dentro de la banda L (1.2-1.4 GHz), son los más adaptados para monitorear la humedad de suelo supericial debido a su alta sensibilidad, profundidad de penetración y sus características de construcción (Dobson, et al., 1985). Dentro de las misiones satelitales dedicadas al monitoreo de la humedad de suelo, actualmente, se encuentran la Soil Moisture and Ocean Salinity (SMOS) de la Agencia Espacial Europea, lanzada en noviembre de 2009, y la Soil Moisture Active/Passive (SMAP) de la NASA (Na-

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Plant composition of a pasture as a predictor of soil salinity

Plant composition of a pasture as a predictor of soil salinity

the soil. The precision this is even higher than that �hown in Table (76% vs. 73%),but the precision ofthe match with the correspOnding homogeneous matrix is also higher (51% vs. 47%), and the measure of homogeneity is lower (148.2 vs. 178.9). In spite of its overall poorer performance, indicated by the '1: measure, the arbitrary categorisat on of quadrats can also provide an algorithm for the quick prediction of categories. Predictions that the soil salinity was low were much more precise (146/151=97%) tban predictions of the high salinity class (39/58=67%), while the most predict was the intermediate salinity category (6/43=14%). Therewere 17 cases

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Selecting Soil Salinity Layer that Better Correlates with Sugarcane Recoverable Sugar Yield

Selecting Soil Salinity Layer that Better Correlates with Sugarcane Recoverable Sugar Yield

different ages, fertilized with 5 N doses and a control without fertilization. Lineal correlations between sugar yield and salinity, expressed as Electrical Conductivity of saturation extract (CEe), of different soil layers (0-30 cm, 30-60, 60-90, mean 0-60, mean 0-90, higher salty layer 0-60, and less salty layer 0-60 cm) were calculated. Moreover, sugar yield was correlated with ten arithmetical and pondered means of salinity measured before planting and after harvesting. Higher correlation was found for salinity measures before planting than with measures after harvesting. The highest correlations with sugar yields utilizing salinity measures before planting, corresponded with mean 0-60 cm salinity layer, with R values between 0.27 and 0.84 (p<0.01), the less salty layer 0-60 cm, with R between 0.47 (p<0.01) and 0.82 (p<0.01), and the most salty layer 0-60 cm with values from 0.04 to 0.81 (p<0.01). Conclusion: it is enough sampling and analyzing soils just to 60 cm before planting. Keywords: Saccharum spp., soil salinity, recoverable sugar yield

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High end Experience

High end Experience

High End Experience contará con una oficina principal en Miraflores para poder atender al público asiduo de la zona que quiera comprar nuestros paquetes turísticos y así tener una venta de manera directa. Por otro lado, se mantendrá comunicación constante por redes sociales y correo electrónico para informar a los clientes sobre promociones y fechas de salidas fijas que quieran disfrutar. Cabe resaltar que tomamos en cuenta estos medios de comunicación gracias a los resultados manifestados en las encuestas siendo un 47,77% los interesados en recibir información por redes sociales y un 44,7% los interesados en obtener información por medio de correo exactamente.

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Increased neurotransmitter release at the neuromuscular junction in a mouse model of polyglutamine disease.

Increased neurotransmitter release at the neuromuscular junction in a mouse model of polyglutamine disease.

In Huntington’s disease (HD), the expansion of polyglutamine (polyQ) repeats at the N terminus of the ubiquitous protein huntingtin (htt) leads to neurodegeneration in specific brain areas. Neurons degenerating in HD develop synaptic dysfunctions. However, it is unknown whether mutant htt impacts synaptic function in general. To investigate that, we have focused on the nerve terminals of motor neurons that typically do not degenerate in HD. Here, we have studied synaptic transmission at the neuromuscular junction of transgenic mice expressing a mutant form of htt (R6/1 mice). We have found that the size and frequency of miniature endplate potentials are similar in R6/1 and control mice. In contrast, the amplitude of evoked endplate potentials in R6/1 mice is increased compared to controls. Consistent with a presynaptic increase of release probability, synaptic depression under high-frequency stimulation is higher in R6/1 mice. In addition, no changes were detected in the size and dynamics of the recycling synaptic vesicle pool. Moreover, we have found increased amounts of the synaptic vesicle proteins synaptobrevin 1,2/VAMP 1,2 and cysteine string protein- ␣ , and the SNARE protein SNAP-25, concomitant with normal levels of other synaptic vesicle markers. Our results reveal that the transgenic expression of a mutant form of htt leads to an unexpected gain of synaptic function. That phenotype is likely not secondary to neurodegeneration and might be due to a primary deregulation in synaptic protein levels. Our findings could be relevant to understand synaptic toxic effects of proteins with abnormal polyQ repeats.

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Fitoplancton costero en Cabo Marzo y Punta Cruces, margen nororiental del Océano Pacífico colombiano

Fitoplancton costero en Cabo Marzo y Punta Cruces, margen nororiental del Océano Pacífico colombiano

In the coastal environment of this sector a high spa- tial and temporal heterogeneity of physical and chemi- cal conditions develops due to the continued ingress of shelf water [8, 9], resulting in a functional and/or nume- ric response in the different biological components of the system [10, 11, 12]. Regarding the phytoplankton, various elements that influence the diversity and pro- ductivity in coastal environments have been proposed, including, the simultaneous action of abiotic factors such as inland nutrient flows, availability of light and thermal variability and local salt, and of biotic factors such as grazing and competition [13-18]. Therefore, through the studies of productivity of the marine pe- lagic ecosystem, it is necessary to identify the factors and understand the mechanisms that modulate the autotrophic component, since phytoplankton is a key component that forms the basis of the marine food web [19-24].

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Growth of a mangrove (Rhizophora apiculata) seedlings as influenced by GA3, light and salinity

Growth of a mangrove (Rhizophora apiculata) seedlings as influenced by GA3, light and salinity

MATERIALS AND METHODS Propagules of R. apiculata Blume with a length of 28 ± 2 cm were collected during September l999, from Pichavaram mangrove forest (Lat. 11° 27’ N; Long. 79° 47’ E), south- east coast of India. The propagules were placed separately in 500 ml beakers containing 300 ml of filtered seawater adjusted with tap water to three levels of salinity viz., 0 (tap water alone), 15 and 30 g l -1 , and with GA

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TítuloAssociations between Profiles of Self Esteem and Achievement Goals and the Protection of Self Worth in University Students

TítuloAssociations between Profiles of Self Esteem and Achievement Goals and the Protection of Self Worth in University Students

Finally, and also as expected, we observed a second profile of students with low self-esteem. In terms of achievement goals, this student profile combines a high interest in learning (i.e., learning goals) with a moderate concern over presenting a social image of incompetence (performance avoidance goals) and a strong desire to stand out and be considered a high performer (performance approach goals). In line with this finding, some works on multiple goals in university students [49,61] have observed a profile that combines the adoption of learning goals with both types of performance goals in a high degree. As stated by Wormington and Linnenbrick-García [64], this student profile has generally been considered equally as adaptive as the profile of high learning goals and low performance goals (i.e., avoidance and approach) in terms of engagement and performance. However, less beneficial outcomes have been observed regarding control beliefs and emotional wellbeing. Accordingly, the students who conjugate high learning goals with moderate performance avoidance goals and high performance approach goals usually exhibit high academic engagement and performance but vulnerability, for example, anxiety, stress, fear of failure [85], linked to social comparison. The results of our study expand the characterization of this motivational profile by specifying that these students have low self-esteem.

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Benthic communities on hard substrates covered by Limnoperna fortunei Dunker (Bivalvia, Mytilidae) at an estuarine beach (Río de la Plata, Argentina)

Benthic communities on hard substrates covered by Limnoperna fortunei Dunker (Bivalvia, Mytilidae) at an estuarine beach (Río de la Plata, Argentina)

zones with high organic matter in the sediments. The Ne- matoda is highly resistant to desiccation, low dissolved-oxy- gen concentrations, and a broad range of temperature (Ocón et al. 2008; Adão 2009). In previous studies of benthic fauna on hard substrates (Darrigran et al. 1998) the Nematoda was not taken into account in the analysis, but in our samples we did consider the Nematoda along with L. fortunei as being the central faunal groups because of their constant domi- nance within the community assemblage. The Oligochaeta and the Hirudinea were the next principal groups that ap- peared during every month. Before the introduction of L. fortunei at Bagliardi Beach, Gullo, and Darrigran (1991) had described two species of Hirudinea and three species of Oligochaeta at this site. After the settlement of the golden mussel, Darrigran et al. (1998) reported eight species of Hirudinea and eight species of Oligochaeta there. According to those authors, Helobdella spp. was the dominant group of Hirudinea, while the Tubificinae and the Naidinae were the principal groups of the Oligochaeta. After the invasion of L. fortunei, the indigenous species of Gastropoda, Chilina

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Green energy generation by pressure retarded osmosis: State of the art and technical advancement—review

Green energy generation by pressure retarded osmosis: State of the art and technical advancement—review

Pressure retarded osmosis is a novel technology, although it already has a long history, starting from the first article that was published by Pattle (1954). Since then, the concept of PRO has received spasmodic attention, mainly in the form of design studies and economic viability evaluations. It has not yet been fully developed, due to the inadequate separation capabilities of semi-permeable membranes, the expected high cost, and the relatively low trans-membrane water flux (Skilhagen et al. 2008, Lee et al. 1981, Yip et al 2011). Pattle described how to use osmotic energy and semi-permeable membranes to produce power by mixing freshwater and saltwater in a Nature article, describing that when a volume V of a pure solvent mixes with a much larger volume of a solution of osmotic pressure π , the free energy released is equal to πV . No work was then published on PRO for around 20 years.

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Full PDF

Full PDF

Nwankwo (1984) who reported that Melosira was the dominant species in Lagos lagoon and the adjacent sea. The dominance of centric diatoms most especially Aulacoseira granulata could be an indication that Aulacoseira species needed low salinity level to thrive, since an increased salinity value especially in Septem- ber 2003, favored the blue green algae during which highest relative abundance (96.7%) was recorded with Microcystis aeruginosa record- ing 95.5% out of the total (96.7%), this indi- cated that salinity range of 0.85-1.05mg/L probably favored M. aeruginosa and not Aula- coseira sp. In general, pH value recorded in this study highly favored A. granulata which remained dominant at most of the time and this supported Talling (1986) report, who by using data collected from some central African lakes suggested that the effects of pH and alkalinity in lake waters may be reflected in the occur- rence of some species such as A. granulata.

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Delimitation of the Coastal Transition Zone in the Gulf of Guayaquil, Ecuador

Delimitation of the Coastal Transition Zone in the Gulf of Guayaquil, Ecuador

The article presents a methodology for the delimitation of the coastal transition zone (CTZ) and the identification of zones with distinct soil properties in the Gulf of Guayaquil (GG), Ecuador. The Gulf was chosen as study area for its urban, economic and ecological potential, more in particular for its rich marine and agricultural resources, and biodiversity. Soil physical and chemical methods, such as soil salinity indices, physical and chemical parameters, coupled with multivariate analysis enabled the delimitation of the CTZ and the grouping of the studied soil transets in three clusters with distinct properties, located in the GG from the limit of the mangrove swamp. Whereas the average conductance in the swamp area is around 27.17 mS cm -1 , inland to the isoline

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