Peripheral responses to attended and unattended angry prosody: a dichotic listening paradigm.

We investigated the effects of angry prosody, varying focus of attention, and laterality of presentation of angry prosody on peripheral nervous system activity. Participants paid attention to either their left or their right ear while performing a sex discrimination task on dichotically presented pseudo-words. These pseudo-words were characterized by either angry or neutral prosody and presented stereophonically (anger/neutral, neutral/anger, or neutral/neutral, for the left/right ear, respectively). Reaction times and physiological responses (heart period, skin conductance, finger and forehead temperature) in this study were differentially sensitive to the effects of anger versus neutral prosody, varying focus of attention, and laterality of presentation of angry prosody.

The Sensitivity of Physiological Measures to Phobic and Nonphobic Fear Intensity

We investigated whether amygdala activation, autonomic responses, respiratory responses, and facial muscle activity (measured over the brow and cheek [fear grin] regions) are all sensitive to phobic versus nonphobic fear and, more importantly, whether effects in these variables vary as a function of both phobic and nonphobic fear intensity. Spider-phobic and comparably low spider-fearful control participants imagined encountering different animals and rated their subjective fear while their central and peripheral nervous system activity was measured. All measures included in our study were sensitive to variations in subjective fear, but were related to different ranges and positions on the subjective fear level continuum. Left amygdala activation, heart rate, and facial muscle activity over the cheek region captured fear intensity variations even within narrowly described regions on the fear level continuum (here within extremely low levels of fear and within considerable phobic fear). Skin conductance and facial muscle activity over the brow region did not capture fear intensity variations within low levels of fear: skin conductance mirrored only extreme levels of fear, and activity over the brow region distinguished phobic from nonphobic fear but also low-to-moderate and high phobic fear. Finally, respiratory measures distinguished phobic from nonphobic fear with no further differentiation within phobic and nonphobic fear. We conclude that a careful consideration of the measures to be used in an investigation and the population to be examined can be critical in order to obtain significant results.

Searching the hearts of graphene-like molecules for simplicity, sensitivity and logic

If quantum interference patterns in the hearts of polycyclic aromatic hydrocarbons (PAHs) could be isolated and manipulated, then a significant step towards realizing the potential of single-molecule electronics would be achieved. Here we demonstrate experimentally and theoretically that a simple, parameter-free, analytic theory of interference patterns evaluated at the mid-point of the HOMO-LUMO gap (referred to as M-functions) correctly predicts conductance ratios of molecules with pyrene, naphthalene, anthracene, anthanthrene or azulene hearts. M-functions provide new design strategies for identifying molecules with phase-coherent logic functions and enhancing the sensitivity of molecular-scale interferometers.

Inhibition of photosynthesis by high temperature in oak (Quercus pubescens L.) leaves grown under natural conditions closely correlates with a reversible heat-dependent reduction of the activation state of ribulose-1,5-bisphosphate carboxylase/oxygenase

Inhibition of the net photosynthetic CO2 assimilation rate (Pn) by high temperature was examined in oak (Quercus pubescens L.) leaves grown under natural conditions. Combined measurements of gas exchange and chlorophyll (Chl) a fluorescence were employed to differentiate between inhibition originating from heat effects on components of the thylakoid membranes and that resulting from effects on photosynthetic carbon metabolism. Regardless of whether temperature was increased rapidly or gradually, Pn decreased with increasing leaf temperature and was more than 90% reduced at 45 ��C as compared to 25 ��C. Inhibition of Pn by heat stress did not result from reduced stomatal conductance (gs), as heat-induced reduction of gs was accompanied by an increase of the intercellular CO2 concentration (Ci). Chl a fluorescence measurements revealed that between 25 and 45 ��C heat-dependent alterations of thylakoid-associated processes contributed only marginally, if at all, to the inhibition of Pn by heat stress, with photosystem II being remarkably well protected against thermal inactivation. The activation state of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) decreased from about 90% at 25 ��C to less than 30% at 45 ��C. Heat stress did not affect Rubisco per se, since full activity could be restored by incubation with CO2 and Mg2+. Western-blot analysis of leaf extracts disclosed the presence of two Rubisco activase polypeptides, but heat stress did not alter the profile of the activase bands. Inhibition of Pn at high leaf temperature could be markedly reduced by artificially increasing Ci. A high Ci also stimulated photosynthetic electron transport and resulted in reduced non-photochemical fluorescence quenching. Recovery experiments showed that heat-dependent inhibition of Pn was largely, if not fully, reversible. The present results demonstrate that in Q. pubescens leaves the thylakoid membranes in general and photosynthetic electron transport in particular were well protected against heat-induced perturbations and that inhibition of Pn by high temperature closely correlated with a reversible heat-dependent reduction of the Rubisco activation state.

A heteromeric potassium channel involved in the modulation of the plasma membrane potential is essential for the survival of African trypanosomes.

Discovery of novel drug targets may lead to improved treatment of trypanosomiasis. We characterize here 2 gene products of Trypanosoma brucei that are essential for the growth of bloodstream form (BSF) parasites, as shown by RNA interference (RNAi)-mediated down-regulation of the individual mRNAs. The primary sequences of the 2 proteins--protein encoded by gene Tb927.1.4450 (TbK1) and protein encoded by gene Tb927.9.4820 (TbK2)--indicate that both belong to the family of putative, Ca(2+)-activated potassium channels. The proteins were expressed in Xenopus laevis oocytes and their functions investigated by use of electrophysiological techniques. Only combined expression of TbK1 and TbK2 results in the formation of sizeable currents, indicating that these proteins probably assemble into a heteromeric ion channel. The current mediated by this channel shows little time and voltage dependence and displays a permeability ratio of K(+)/Na(+) of >20. The known potassium channel blocker barium inhibits this channel with a half-maximal inhibitory concentration (IC50) of 98 �� 15 ��M. The membrane potential of trypanosomes was measured with a fluorescent dye. Individual RNAi-mediated down-regulation of TbK1 or TbK2 eliminates a potassium conductance in the plasma membrane of BSF. Thus, this heteromeric potassium channel is involved in the modulation of the plasma membrane potential and represents a novel drug target in T. brucei.

Monepantel irreversibly binds to and opens Haemonchus contortus MPTL-1 and Caenorhabditis elegans ACR-20 receptors.

Monepantel is a recently developed anthelmintic with a novel mode of action. Parasitic nematodes with reduced sensitivity to monepantel have led to the identification of MPTL-1, a ligand-gated ion-channel subunit of the parasitic nematode Haemonchus contortus, as a potential drug target. Homomeric MPTL-1 channels reconstituted in Xenopus oocytes are gated by ��M concentrations of betaine and mM concentrations of choline. Measurement of reversal potentials indicated that the channel has a similar conductance for Na(+) and K(+) ions and does not permeate Ca(2+). Concentrations of monepantel (amino-acetonitrile derivative [AAD]-2225) >0.1 ��M, but not its inactive enantiomer AAD-2224, induced channel opening in an irreversible manner. Currents elicited by monepantel alone were larger than the maximal current amplitudes achieved with betaine or choline, making monepantel a superagonist. Currents elicited by betaine or choline were allosterically potentiated by nM concentrations of monepantel and to a much smaller degree by AAD-2224. We have also reconstituted the Caenorhabditis elegans homomeric ACR-20 receptor in Xenopus oocytes. The acr-20 sequence has higher similarity to mptl-1 than acr-23, the primary target for monepantel mode of action in C. elegans. The ACR-20 channel is gated similarly as MPTL-1. Monepantel, but not AAD-2224, was able to induce channel opening in an irreversible manner at similar concentrations as for MPTL-1. Interestingly, the allosteric potentiation measured in the presence of betaine was much smaller than in MPTL-1 receptors. Together, these results establish the mode of action of monepantel in H. contortus and contribute to our understanding of the mode of action of this anthelmintic.

Simulated heat waves affected alpine grassland only in combination with drought

The Alpine region is warming fast, and concurrently, the frequency and intensity of climate extremes are increasing. It is currently unclear whether alpine ecosystems are sensitive or resistant to such extremes. We subjected Swiss alpine grassland communities to heat waves with varying intensity by transplanting monoliths to four different elevations (2440���660 m above sea level) for 17 d. Half of these were regularly irrigated while the other half were deprived of irrigation to additionally induce a drought at each site. Heat waves had no significant impacts on fluorescence (Fv/Fm, a stress indicator), senescence and aboveground productivity if irrigation was provided. However, when heat waves coincided with drought, the plants showed clear signs of stress, resulting in vegetation browning and reduced phytomass production. This likely resulted from direct drought effects, but also, as measurements of stomatal conductance and canopy temperatures suggest, from increased high-temperature stress as water scarcity decreased heat mitigation through transpiration. The immediate responses to heat waves (with or without droughts) recorded in these alpine grasslands were similar to those observed in the more extensively studied grasslands from temperate climates. Responses following climate extremes may differ in alpine environments, however, because the short growing season likely constrains recovery.

Drought stress and carbon assimilation in a warming climate: Reversible and irreversible impacts

Abstract Global change is characterized by increased {CO2} concentration in the atmosphere, increasing average temperature and more frequent extreme events including drought periods, heat waves and flooding. Especially the impacts of drought and of elevated temperature on carbon assimilation are considered in this review. Effects of extreme events on the subcellular level as well as on the whole plant level may be reversible, partially reversible or irreversible. The photosynthetically active biomass depends on the number and the size of mature leaves and the photosynthetic activity in this biomass during stress and subsequent recovery phases. The total area of active leaves is determined by leaf expansion and senescence, while net photosynthesis per leaf area is primarily influenced by stomatal opening (stomatal conductance), mesophyll conductance, activity of the photosynthetic apparatus (light absorption and electron transport, activity of the Calvin cycle) and {CO2} release by decarboxylation reactions (photorespiration, dark respiration). Water status, stomatal opening and leaf temperature represent a "magic triangle" of three strongly interacting parameters. The response of stomata to altered environmental conditions is important for stomatal limitations. Rubisco protein is quite thermotolerant, but the enzyme becomes at elevated temperature more rapidly inactivated (decarbamylation, reversible effect) and must be reactivated by Rubisco activase (carbamylation of a lysine residue). Rubisco activase is present under two forms (encoded by separate genes or products of alternative splicing of the pre-mRNA from one gene) and is very thermosensitive. Rubisco activase was identified as a key protein for photosynthesis at elevated temperature (non-stomatal limitation). During a moderate heat stress Rubisco activase is reversibly inactivated, but during a more severe stress (higher temperature and/or longer exposure) the protein is irreversibly inactivated, insolubilized and finally degraded. On the level of the leaf, this loss of photosynthetic activity may still be reversible when new Rubisco activase is produced by protein synthesis. Rubisco activase as well as enzymes involved in the detoxification of reactive oxygen species or in osmoregulation are considered as important targets for breeding crop plants which are still productive under drought and/or at elevated leaf temperature in a changing climate.

Gibberellin Deficiency Confers Both Lodging and Drought Tolerance in Small Cereals

Tef [Eragrostis tef (Zucc.) Trotter] and finger millet [Eleusine coracana Gaertn] are staple cereal crops in Africa and Asia with several desirable agronomic and nutritional properties. Tef is becoming a life-style crop as it is gluten-free while finger millet has a low glycemic index which makes it an ideal food for diabetic patients. However, both tef and finger millet have extremely low grain yields mainly due to moisture scarcity and susceptibility of the plants to lodging. In this study, the effects of gibberellic acid (GA) inhibitors particularly paclobutrazol (PBZ) on diverse physiological and yield-related parameters were investigated and compared to GA mutants in rice (Oryza sativa L.). The application of PBZ to tef and finger millet significantly reduced the plant height and increased lodging tolerance. Remarkably, PBZ also enhanced the tolerance of both tef and finger millet to moisture deficit. Under moisture scarcity, tef plants treated with PBZ did not exhibit drought-related symptoms and their stomatal conductance was unaltered, leading to higher shoot biomass and grain yield. Semi-dwarf rice mutants altered in GA biosynthesis, were also shown to have improved tolerance to dehydration. The combination of traits (drought tolerance, lodging tolerance and increased yield) that we found in plants with altered GA pathway is of importance to breeders who would otherwise rely on extensive crossing to introgress each trait individually. The key role played by PBZ in the tolerance to both lodging and drought calls for further studies using mutants in the GA biosynthesis pathway in order to obtain candidate lines which can be incorporated into crop-breeding programs to create lodging tolerant and climate-smart crops.

Diversity of neuronal connexins in the mammalian retina

Many neurons in the mammalian retina are electrically coupled by intercellular channels or gap junctions, which are assembled from a family of proteins called connexins. Numerous studies indicate that gap junctions differ in properties such as conductance and tracer permeability. For example, A-type horizontal cell gap junctions are permeable to Lucifer Yellow, but B-type horizontal cell gap junctions are not. This suggests the two cell types express different connexins. My hypothesis is that multiple neuronal connexins are expressed in the mammalian retina in a cell type specific manner. Immunohistochemical techniques and confocal microscopy were used to localize certain connexins within well-defined neuronal circuits. The results of this study can be summarized as follows: AII amacrine cells, which receive direct input from rod bipolar cells, are well-coupled to neighboring AIIs. In addition, AII amacrine cells also form gap junctions with ON cone bipolar cells. This is a complex heterocellular network. In both rabbit and primate retina, connexin36 occurs at dendritic crossings in the AII matrix as well as between AIIs and ON cone bipolar cells. Coupling in the AII network is thought to reduce noise in the rod pathway while AII/bipolar gap junctions are required for the transmission of rod signals to ON ganglion cells. In the outer plexiform layer, connexin36 forms gap junctions between cones and between rods and cones via cone telodendria. Cone to cone coupling is thought to reduce noise and is partly color selective. Rod to cone coupling forms an alternative rod pathway thought to operate at intermediate light intensity. A-type horizontal cells in the rabbit retina are strongly coupled via massive low resistance gap junctions composed from Cx50. Coupling dramatically extends the receptive field of horizontal cells and the modulation of coupling is thought to change the strength of the feedback signal from horizontal cells to cones. Finally, there are other coupled networks, such as B-type horizontal cells and S1/S2 amacrine cells, which do not use either connexin36 or Cx50. These results confirm the hypothesis that multiple neuronal connexins are expressed in the mammalian retina and these connexins are localized to particular retinal circuits. ^

RUNOFF FROM COAL PILES: EFFECTS ON THE ENVIRONMENT AND THE PUBLIC'S HEALTH

The use of coal for fuel in place of oil and natural gas has been increasing in the United States. Typically, users store their reserves of coal outdoors in large piles and rainfall on the coal creates runoffs which may contain materials hazardous to the environment and the public's health. To study this hazard, rainfall on model coal piles was simulated, using deionized water and four coals of varying sulfur content. The simulated surface runoffs were collected during 9 rainfall simulations spaced 15 days apart. The runoffs were analyzed for 13 standard water quality parameters, extracted with organic solvents and then analyzed with capillary column GC/MS, and the extracts were tested for mutagenicity with the Ames Salmonella microsomal assay and for clastogenicity with Chinese hamster ovary cells.^ The runoffs from the high-sulfur coals and the lignite exhibited extremes of pH (acidity), specific conductance, chemical oxygen demand, and total suspended solids; the low-sulfur coal runoffs did not exhibit these extremes. Without treatment, effluents from these high-sulfur coals and lignite would not comply with federal water quality guidelines.^ Most extracts of the simulated surface runoffs contained at least 10 organic compounds including polycyclic aromatic hydrocarbons, their methyl and ethyl homologs, olefins, paraffins, and some terpenes. The concentrations of these compounds were generally less than 50 (mu)g/l in most extracts.^ Some of the extracts were weakly mutagenic and affected both a DNA-repair proficient and deficient Salmonella strain. The addition of S9 decreased the effect significantly. Extracts of runoffs from the low-sulfur coal were not mutagenic.^ All extracts were clastogenic. Extracts of runoffs from the high-sulfur coals were both clastogenic and cytotoxic; those from the low-sulfur coal and the lignite were less clastogenic and not cytotoxic. Clastogenicity occurred with and without S9 activation. Chromosomal lesions included gaps, breaks and exchanges. These data suggest a relationship between the sulfur content of a coal, its mutagenicity and also its clastogenicity.^ The runoffs from actual coal piles should be investigated for possible genotoxic effects in view of the data presented in this study.^

Relaciones entre cavitaci��n y cierre estom��tico en vides sometidas a d��ficit h��drico

La cavitaci��n es una disfunci��n fisiol��gica que ocurre en el xilema de las plantas cuando estas est��n bajo d��ficit h��drico, y que entra��a una p��rdida de su conductancia hidr��ulica (kL), cuando algunos vasos se llenan de aire. Esto incide negativamente sobre la oferta de agua y afecta el potencial h��drico foliar (��L) y la hidrataci��n de la canopia. El cierre estom��tico es una respuesta efectiva ante la disminuci��n del contenido h��drico. Dependiendo de la especie vegetal, los estomas suelen cerrase para evitar la cavitaci��n catastr��fica. Una planta poco vulnerable a cavitar puede mantenerlos abiertos por m��s tiempo y por lo tanto seguir fotosintetizando. Por el contrario, plantas vulnerables a la cavitaci��n deben cerrar sus estomas con anterioridad para poder evitar cavitaciones graves. En este trabajo se estudi��, el ajuste estom��tico como mecanismo para evitar la cavitaci��n en cuatro variedades contrastantes de vid (Grenache, Syrah, Malbec y Chardonnay). Se hipotetiz�� que las vides sometidas a d��ficit h��drico disminuyen gs para evitar sufrir cavitaciones catastr��ficas y que algunas variedades de vid, cuando crecen bajo restricci��n h��drica, se aclimatan mejor desarrollando un ajuste estom��tico m��s preciso, �� un sistema conductor menos vulnerable a cavitar, o ambas. Se dise���� un experimento aleatorizado en invern��culo donde se probaron dos situaciones h��dricas ed��ficas (100% y 50% de FTSW). Luego de dos meses, se midieron, a lo largo del d��a, las variables gs, transpiraci��n y potencial h��drico. Luego se construyeron las curvas de cavitaci��n y se calcul�� la conduactancia hidr��ulica de la planta (kL) y el embolismo a lo largo del d��a. Finalmente se obtuvo la relaci��n entre gs, kL y el embolismo. Mediante un modelo mecan��stico, que se construy�� teniendo en cuenta los flujos de agua y vapor, las kL y gs, y la vulnerabilidad del xilema a cavitar; se prob�� que gs no es la ��nica variable responsable de frenar la embolia. Se determin�� que gs y kL est��n ��ntimamente asociadas y que este acople entre ambas conductancias es lo que frena la embolia. Se concluy�� que, en la vid y bajo niveles de estr��s h��drico moderado, no es necesario un cierre estom��tico para controlar la cavitaci��n, sino una disminuci��n de la diferencia entre gs y kL (��gs). Por esto, el mecanismo de control de la cavitaci��n en la vid no conlleva un costo en t��rminos de intercambio gaseoso. Tambi��n se descubri�� que bajo niveles moderados de d��ficit h��drico la vulnerabilidad xilem��tica no aumenta con respecto a las plantas que no sufren d��ficit, sin importar de qu�� variedad se trate.

Regulaci��n de la hidrataci��n y la turgencia foliares por mecanismos evitadores del estr��s, y resistencia a d��ficit h��drico en vid

El transporte del agua en las plantas es impulsado por diferencias de energ��a libre entre el suelo y la atm��sfera, y est�� regulado por mecanismos biol��gicos evitadores, como el cierre estom��tico. La hidrataci��n y la turgencia foliares resultan del equilibrio entre ��L del apoplasto, el potencial osm��tico del simplasto y la elasticidad de los tejidos. Sobre esta base se conjetur�� que las interacciones de los mecanismos evitadores del estr��s h��drico de la planta tienen un rol clave en la definici��n de su resistencia a d��ficit h��drico. Para probar esta hip��tesis se construy�� un modelo mecan��stico basado en las leyes del flujo de savia de Van de Honert, de difusi��n de Fick, de elasticidad de Hooke, la ecuaci��n de Gardner para el flujo del agua en la riz��sfera y el modelo de conductancia estom��tica (gs) de Buckley. Mediante el modelo se demostr�� te��ricamente que la hidrataci��n y la turgencia foliares dependen de la oferta de agua ed��fica (representada por el potencial h��drico del suelo) y de la demanda evaporativa de la atm��sfera (representada por la radiaci��n absorbida, la temperatura del aire, la velocidad del viento y el d��ficit de presi��n de vapor de la atm��sfera). Tambi��n que los mecanismos evitadores del estr��s h��drico -i.e., conductancia hidr��ulica de la planta, conductancia estom��tica, elasticidad del tejido y potencial osm��tico a turgencia m��xima- son todos necesarios para determinar la hidrataci��n y la turgencia foliares. El modelo tambi��n demostr�� que la conductancia hidr��ulica suelo-hoja (kL) depende de la fracci��n de agua ed��fica transpirable (FTSW) con un patr��n de decaimiento sigmoide, a medida que el suelo se seca. Esto implica que las variables que dependen en parte de kL (i.e., gs, transpiraci��n, fotos��ntesis y superficie foliar) tambi��n dependen de FTSW con el mismo patr��n. El modelo se prob�� experimentalmente a distintos niveles de humedad ed��fica (desde d��ficit h��drico nulo, hasta severo) en cinco variedades de vid y mostr�� un poder predictivo superior al 90%. En todas las variedades las gs se asociaron linealmente con las kL observadas, al considerar todas las situaciones de d��ficit h��drico en conjunto, si bien la pendiente de estas relaciones fueron distintas en cada variedad. La contrastaci��n experimental mostr�� que, en una escala de tiempo de varios meses, las variedades m��s evitadoras -i.e., Grenache y Cereza- mantuvieron mayor kL, ajuste osm��tico y rigidez de los tejidos y una menor pendiente de la relaci��n de gs vs. kL, que las variedades menos evitadoras -i.e., Malbec y Syrah-. La menor pendiente de la relaci��n entre gs y kL, en las variedades m��s evitadoras, estuvo asociada a una mayor cantidad de estomas, en relaci��n con la cantidad de c��lulas epid��rmicas. Los variedades m��s evitadoras bajo d��ficit h��drico moderado -i.e., con una fracci��n de agua ed��fica transpirable entre 0,6 y 0,4- tuvieron mayor superficie foliar y produjeron m��s biomasa, favoreciendo ra��ces profundas y densas, y ahorrando agua. Chardonnay mantuvo una alta hidrataci��n y turgencia a expensas de un alto gasto de agua debido a que privilegiaba una alta kL por sobre el ajuste estom��tico, por lo que no podr��a considerarse en forma estricta como muy evitadora.

Influencia de seis portainjertos de vid sobre el comportamiento vit��cola de la cv. Malbec y estudio de las relaciones h��dricas que se establecen

El uso de portainjertos en la vid se ha difundido por su resistencia a filoxera y nem��todos, pero tambi��n por su tolerancia a condiciones adversas del suelo. Por otro lado, los portainjertos modifican las relaciones fuente-destino, influyendo en el comportamiento vegetativo y reproductivo de las plantas y en la composici��n de la uva, lo cu��l puede ser utilizado como una herramienta de manejo agron��mico. A fin de evaluar si existe un comportamiento diferencial de los portainjertos en cuanto a expresi��n vegetativa, vigor, rendimiento y composici��n de la uva, y explicar dichas diferencias en t��rminos de exploraci��n radical, relaciones h��dricas, asimilaci��n de carbono, eficiencia en el uso del agua y partici��n de asimilados se realiz�� un ensa-yo a campo de cv. Malbec sobre seis portainjertos (3309 C, 1103 P, 140 Ru, SO4, Harmony y Cereza) y a pie franco. Los portainjertos 140 Ru, 1103 P y SO4 tuvieron una mayor tendencia a la producci��n de uva (mayor ��ndice de Ravaz), y Franco, Cereza y 3309 C a vegetar, mostrando Harmony una situaci��n intermedia. Las ba-yas sobre el pie Cereza tuvieron un mayor peso (1,96 g) que sobre Harmony (1,75 g). No se encontraron diferencias en los polifenoles de las bayas entre portainjertos. La fotos��ntesis de la planta entera (Amax) de Franco, 1103 P y SO4 fue mayor que la de Harmony. La conductancia hidr��ulica foliar espec��fica (kL) de Harmony fue me-nor que la de Cereza, y su conductancia hidr��ulica (kH) fue menor que la de Franco, Cereza y SO4. El n��mero de ra��ces totales de 140 Ru fue mayor que el de 1103 P, SO4 y Harmony. El portainjerto 140 Ru se destac�� por privilegiar el desarrollo radi-cal y reproductivo sobre el vegetativo, y por su mayor eficiencia en el uso del agua (EUA). Las diferencias entre portainjertos pueden ser explicadas en parte por dife-rencias en la kL que a su vez incide en el estado h��drico de las plantas (��L). De ma-nera que cuando la kL es m��s baja, el ��L es menor (i.e., Harmony), y cuando la kL es m��s alta, el ��L es mayor (i.e., Franco y Cereza). Mayores ��L se asocian con mayores superficies foliares.

Geophysical investigations in the European Alps

Joint interpretation of magnetotelluric and geomagnetic depth sounding data in the western European Alps offer new insights into the conductivity structure of the Earth's crust and mantle. This first large scale electromagnetic study in the Alps covers a cross-section from Germany to northern Italy and shows the importance of the alpine mountain chain as an interrupter of continuous conductors. Poor data quality due to the highly crystalline underground is overcome by Remote Reference and Robust Processing techniques. 3d-forward-modelling reveals on the one hand interrupted dipping crustal conductors with maximum conductance of 4960 S and on the other hand a lithosphere thickening up to 208 km beneath the central western Alps. Graphite networks arising from Paleozoic sedimentary deposits are considered to be accountable for the occurrence of high conductivity and the distribution pattern of crustal conductors. The influence of huge sedimentary molasse basins on the electromagnetic data is suggested to be minor compared with the influence of crustal conductors. In conclusion, electromagnetic results can be attributed to the geological, tectonic and palaeogeographical background. Dipping direction (S-SE) and maximum angle (10.1��) of the northern crustal conductor reveal the main thrusting conditions beneath the Helvetic Alps whereas the existence of a crustal conductor in the Brian��onnais supports theses about its palaeographic belonging to the Iberian Peninsula.