1), and ultimately to the Gulf of Mexico. The Platte River watershed today is largely agricultural, with livestock production and corn dominating land-use in this semi-arid

part of the U.S. Because of its headwaters in the Rocky Mountains, river flow is largely governed by high-altitude spring snowmelt. Prior to European settlement, the Platte was a wide, shallow, anabranching river with sparse vegetation (Johnson, 1994). As in many rivers in semi-arid environments, thousands of diversion canals were constructed in the 1900s to irrigate farmland, and several large dams were built in its upper reaches. The result was large evaporative loss of water from the system and tightly regulated flows so that today, the Platte often carries as little as 20% of its original, unregulated flow (Randle and Samad, 2003). buy Cilengitide The reduction in flow led to dramatic changes in river morphology, sediment transport, and vegetation. Various studies have documented conversion of the river from wide and braided with little to no vegetation in the channel, to a much narrower, anabranching or locally meandering

river (Eschner et al., 1983, Fotherby, 2008, Johnson, 1994, Johnson, 1997 and Kircher and Karlinger, 1983). Woodland expansion began in the channel around 1900. By the 1930s much of the channel’s riparian zone had been colonized by Populus (cottonwood) and Salix (willow) species, both fast-growing woody plants ( Johnson, 1994). By the 1960s, a new equilibrium appeared to have been reached between woodland, lightly vegetated selleck chemicals llc areas and unvegetated areas in the channel ( Johnson, 1997 and Johnson, 1998). In 2002, non-native Phragmites first appeared in the river and

rapidly spread. It colonized riparian areas that had been inhabited by Salix and other species as well as unvegetated parts of the riverbed that were newly exposed by record-low river flows. By 2010 it became one of the most abundant types of vegetation in over 500 km of the river’s riparian area Interleukin-2 receptor ( R. Walters, pers. comm., 2010). Phragmites is a non-native grass introduced from Eurasia that has invaded wetlands across North America ( Kettenring et al., 2012). It is considered invasive because of its prolific growth and reproduction and unique physiology: it is able to quickly outcompete resident native vegetation – including the native Phragmites subspecies americanus – in many habitats ( Kettenring et al., 2012, Kettenring and Mock, 2012 and Mozdzer et al., 2013). Previous studies conducted in North America have documented the impact of non-native Phragmites on nutrients other than silica, particularly nitrogen cycling ( Meyerson et al., 1999 and Windham and Meyerson, 2013). Study sites were located along a 65 km stretch of the Platte River in Nebraska between Kearney and Grand Island (Fig. 2).

, 2003 and Li and Pan, 2005). Treatment with ANG II also decreased the amplitude of evoked IPSCs and the frequency of miniature IPSCs in neurons of the dorsolateral periaqueductal gray, an effect blocked by losartan, but not by

the AT2 antagonist PD123319 (Xing et al., 2009). Treatment with ANG II had no effect on excitatory post synaptic currents in the PVN neurons or in the dorsolateral S3I-201 solubility dmso periaqueductal gray (Li et al., 2003, Li and Pan, 2005 and Xing et al., 2009). In contrast, another study showed that the amplitude of the IPSCs in the MnPO was reduced by the treatment with losartan, suggesting a post synaptic action of endogenous ANG II that facilitated the effect of the GABAergic input to the MnPO (Henry et al., 2009). Considering the effects of the activation of GABAA receptors in the LPBN on hypertonic NaCl and water intake (Callera et al., 2005 and De Oliveira et al., 2007) and the results of previous studies showing that AT1 receptor activation may modulate the action of the GABAergic mechanisms (Henry et al.,

2009, Li et al., 2003, Li and Pan, 2005 and Xing et al., 2009), in the present study we investigated the effects of injections of the specific AT1 receptor antagonist, losartan, SB431542 nmr into the LPBN on water and hypertonic NaCl intake induced by the activation of GABAA receptors by muscimol injections into the LPBN in fluid replete or FURO + CAP-treated rats. Fig. 1 is a photomicrograph of a transverse section of the brainstem of one rat, representative of the groups tested, showing the typical bilateral injection sites in the LPBN. The injections were centered in the central lateral and dorsal lateral portions of the LPBN (see Fulwiler and Saper, 1984 for definitions of LPBN subnuclei). In some rats, LPBN injections reached the ventral lateral

Resminostat and external lateral portions, as well as the Kölliker–Fuse nucleus. The sites of injections were similar to those in previous studies that showed the effects of LPBN injections of methysergide, proglumide, moxonidine or muscimol on water and 0.3 M NaCl intake (Andrade et al., 2006, Callera et al., 2005, De Gobbi et al., 2001, De Luca et al., 2003 and De Oliveira et al., 2007). In some rats, injections spread to the brachium (superior cerebellar peduncle), or slightly ventral to this structure, reaching the dorsal portions of the medial parabrachial nucleus (MPBN) uni- or bilaterally. There was no difference in the effects if the injections were restricted to the LPBN or if they spread to the ventral structures described above. ANOVA showed significant differences between treatments for 0.3 M NaCl [F(3, 21) = 20.7; P < 0.001] and water intake [F(3, 21) = 9.05; P < 0.

A starting point for an artificial system that could pass the cellular Turing test could be the construction of a synthetic quorum pathway between an artificial and a natural cell [6]. The inability to define what is being built poses some problems, but also provides room for a variety of different research avenues. Mimics that morphologically resemble a cell, others that carryout similar chemical transformations as natural cells, and artificial systems engineered to pass a Turing-like test all

will deepen our understanding of life. Thus far, most of the progress has been in building bottom-up replication and division mechanisms, but complementary studies are beginning to point to a more exciting phase of bottom-up synthetic biology that better captures the complexities of life. To build something that looks like an extant this website PD0332991 cell, DNA, RNA, protein, and lipids should be assembled in a manner that gives a genetically encoded system with a cytoskeleton and a lipid membrane (Figure 2a). Each of these molecular components can be functionally reconstituted in the laboratory. However, the lack of knowledge concerning the way the biological parts fit

together to give life is obvious when one considers that the successful synthesis of an entire genome [7] required genes of unknown function and a recipient host cell to provide additional components with unknown function. When provided with the required monomeric building blocks, the information stored within a DNA molecule can be used to direct the synthesis of RNA through the activity of a single protein in vitro. Although the synthesis of protein from an RNA template is much more complex, after the Axenfeld syndrome pioneering work of Ueda and co-workers, it is now rather straightforward to carryout translation in vitro [ 8 and 9]. Similarly, the construction of a membrane-defined body to house a cell-like system is achieved easily in vitro. Many lipids spontaneously form vesicle membranes in aqueous solution that efficiently retain large molecules, allow for the selective exchange of small molecules, and are compatible with growth and division.

The interior of a vesicle can be further organized. Polymer solutions, such as polyethylene glycol and dextran, can form distinct aqueous phases to which some molecules preferentially partition depending on their hydrophobicity [ 10]. Since protein synthesis proceeds efficiently in vesicles [11], vesicle structure and organization can be reinforced by the formation of cytoskeletal mimics (Figure 2b and c). Actin polymer filaments can be anchored to lipid membranes [12] and bacterially derived cytoskeletal elements can be assembled inside of vesicles [13]. It should be noted, however, that while active RNA polymerases can be produced through in vitro transcription–translation reactions, the in vitro production of translation machinery has not been achieved to date.

After DNase treatment with Ambion Turbo DNA-free kit (Applied Biosystems, CA, USA), cDNA was synthesised using SuperScript II reverse transcriptase with hexamer random primers (both Invitrogen, CA, USA). Quantification of mRNA transcripts of IL17A, IFNG, IL8 and the reference gene GAPDH was performed using DyNAmo SYBR Green PCR master mix (Finnzymes, Thermo Fisher Scientific, MA, USA) on a Corbett Rotor Gene 3000

system (QIAGEN). Amplification was carried out in triplicate over 40 to 45 cycles of 15 s at 95 °C, 30 s at 61 °C (IFNG, GAPDH) or 62 °C (IL17A, IL8, GAPDH) and 30 s at 72 °C. Included in each assay were commercial human cDNA (Clontech, BD Biosciences, CA, USA) positive controls, no template controls and first-stage RT minus controls. Specificity

Selleck PD0325901 analysis was performed with high resolution melt curves. Results were analysed by Pfaffl’s relative quantification method ( Pfaffl, 2001), normalising against GAPDH and comparing against a pooled Fluorouracil negative comparator prepared from a further 14 uninfected donors. Commercial primers were used for IL17A and IFNG (SABiosciences, QIAGEN). IL8 primers were F: 5′-CTCTTGGCAGCCTTCCTGA and R: 5′-AGTTCTTTAGCACTCCTTGGCA. GAPDH primers were as previously described ( Robinson et al., 2008). Data were analysed with Rotor-Gene software (version 6.1, Corbett Research, UK). Statistical analysis was performed using Prism 6.00 (GraphPad, Software CA, USA). Continuous variables were compared using non-parametric Mann–Whitney U-tests. Two-tailed p < 0.05 was considered significant. One of our Enzalutamide price objectives

was to assess cytokines present at low concentrations and therefore the performance of the three Luminex kits in terms of their sensitivity and assay range. Standard curves provided by each manufacturer were run as recommended but extended to < 1.0 pg/mL to further assess kit sensitivity. As expected all kits performed well within the standard curve ranges recommended by each manufacturer (Table 1), although the Bio-Plex kit was less sensitive for IFNγ in our hands with a lower limit of quantification (LLOQ) of 8.1 pg/mL (vs 1.9 pg/mL lowest recommended standard). The VersaMAP kit had the lowest LLOQ for IFNγ (0.3 pg/mL) although the lowest recommended standard for this kit was 27.2 pg/mL. For IL-17, the Bio-Plex kit was most sensitive with a LLOQ of 1.3 pg/mL. Overall the MILLIPLEX kit performed closest to the specified product characteristics for both analytes. In addition though the upper limits of quantification (ULOQ) were highest with the Bio-Plex kit, the MILLIPLEX kit provided the broadest linear dynamic ranges. Low bead counts for a particular well can reduce confidence in the reported median fluorescence intensity and hence the analyte concentration value interpolated from a standard curve. Manufacturers generally validate their assays with soluble materials such as sera, plasma and cell culture supernatants.

Erythrocytes were lysed by adding ammonium chloride solution (0.13 M) to the samples, and leukocytes were recovered after washing with PBS. Fluorescent dye DCFH-DA (340 μM; diluted in PBS) was added to 2 × 105 cells in a final volume of 1.1 ml. Cells were maintained at 37 °C for 30 min and rinsed

with EDTA (3 mM; 2 ml) to remove the excess dye. Cells were resuspended with PBS. The cells were analyzed in a FACS Calibur flow cytometer (Becton & Dickinson, San Jose, CA, USA). Data from 10,000 events were obtained and only the morphologically viable leukocytes were considered for analysis. Results are presented as arbitrary units of fluorescence. The effects of in vivo exposure to HQ on cell cycle and DNA fragmentation were studied using flow cytometry as previous described by Liu et al. (2005). Blood was collected, using heparin as anti-coagulant, from the GSK2656157 abdominal aorta of vehicle- or HQ-exposed mice, and erythrocytes Ribociclib datasheet were lysed by the addition of ammonium chloride solution (0.13 M). Leukocytes were recovered after washing with Hank’s balanced salt solution (HBSS). Afterward, RNAse A (20 μl; 15 mg/ml) and lysis buffer (140 μl; 2% fetal bovine serum, 0.05% Triton X 100, 0.1% sodium citrate in PBS) containing propidium iodide (20 μg/ml) were added to the leukocytes (1 × 105 cells). The samples were maintained

at room temperature for 30 min and immediately analyzed in a FACS Calibur flow cytometer (Becton & Dickinson, San Jose, CA, USA). Data from 10,000 events were obtained. Results of DNA fragmentation are presented as mean of arbitrary fluorescence units and cell cycle as percentage of labelled cells in each phase. As a positive

control, leukocytes were previously incubated with 10% dimethyl sulfoxide. The means and standard error of the mean (s.e.m.) of all data presented here were compared by Student’s t-test or ANOVA. Tukey’s multiple comparisons test was used to determine the significance of differences between the values for the experimental conditions. The statistical software GraphPad Prism® was used for this purpose. P < 0.05 was considered significant. To see more determine the amount of HQ in the exposure chamber, extracts of the cellulose ester membrane filters exposed for 1 h to 25 ppm HQ were analyzed by HPLC. The data obtained showed that the amount of HQ in the filter was 1.59 μg ± 0.26 (n = 5), which gives a concentration of 0.20 mg/m3 ± 0.09 in the box (according to NIOSH, protocol 5004). This concentration is equivalent to 0.04 ppm HQ (http://www.cdc.gov/niosh/docs/2004-101/calc.htm) and it is 10× lower than the level allowed for human exposure during a course of 8 h/day (0.44 ppm, threshold limit value − time weighted average (TLV − TWA); NIOSH, 1994).

, 2007). Even though it has been produced for over one century, XL184 in vivo Coalho cheese is still manufactured using unstandardized processes, causing variability

in physicochemical, technological and sensory properties. Some sensory descriptive terminology commonly used to characterize Coalho cheeses marketed in Brazil includes leakage of whey for appearance, butter or milk flavor, butter taste and rubbery texture (Cavalcante et al., 2007). Because of its peculiar taste and nutritional properties and its recognition as a healthy food, goat’s milk has received special attention by researchers and dairy industry. Some properties of goat’s milk are known to be advantageous compared with those of cow’s milk, such as higher tolerance by allergic children, which is related to the amount of and structural differences in whey proteins (α-lactalbumin and β-lactalbumin) and the high proportion of small fat globules (1.5 μm), which provide better digestibility (Albenzio & Santillo, 2011; Haenlein, 2004; Raynal-Ljutovac, Gaborit, & Lauret, 2005; Sheehan, Drake, & Mcsweenwy, 2009). Furthermore, goat’s milk has received special attention by researchers because of its recognition as a potential functional food since it holds potential as a natural source of lactose-derived oligosaccharides, present a healthier lipid

composition with increased conjugated-linoleic acid and short fatty acids content and higher vitamin (A and complex B) Cell Cycle inhibitor and calcium content (Haenlein & Anke, 2011; Park, 2006; Silanokove, Leitner, Merin, & Prosser, 2010), which means that may provide a health benefit beyond its nutritional value. Despite the availability of scientific information about the positive aspects of the

consumption of goat’s milk and goat dairy products, the production of this milk in some countries is scarce (such as in Pregnenolone Brazil), limiting the production of goat dairy products. Nevertheless, the Northeastern Region of Brazil is the biggest goat’s milk production region representing 75% of national production (highlighting the state of Paraíba with 18 million liter of milk per day) and its valorization in differentiated dairy products may contribute to the economical sustainability of the region, mainly of rural areas. However, the flavor of this milk is particular and stronger than cow’s milk, which constrains its acceptability among several consumers, in particular Brazilian ones. In this context, the production of dairy products using mixtures of goat’s milk and cow’s milk could be an interesting and feasible opportunity for the dairy market and industry (Thompson, 2007) allowing the expansion of the dairy industry in many regions and strengthen the goat’s milk production chain (Silanokove et al., 2010).

A medição da CFA com o uso do método 3 D modo de inversão tem uma reprodutibilidade interobservador adequada, mas é dependente da qualidade da imagem. Segundo outro trabalho de Jayaprakasan et al. (2007),1 que comparou três métodos de ultrassonografia equivalentes, 2 D, 3 D visão multiplanar e modo de inversão, em mulheres com idade

inferior a 40 anos, as CFA com base em imagens 3 D parecem oferecer uma pequena vantagem sobre métodos com imagem 2 D convencional na predição da resposta ovariana em um programa de FIV. A maior correlação da CFA com o número de folículos que se desenvolvem durante a estimulação ovariana e o número total de oócitos capturados é vista quando a CFA é feita com o método 3 D modo de inversão. Mas esse modo de processamento find more demorou significativamente mais tempo do que todos os outros métodos. Os mesmos autores, em estudo publicado em 2008,13 no qual dois observadores

fizeram ultrassonografia transvaginal em 45 mulheres com os métodos 2 D convencional e 3 D, relatam que o ultrassom 3 D melhora significativamente a confiabilidade interobservador da CFA. Os autores concluíram ainda que a duração total do exame de ultrassom foi significativamente reduzida quando foi usado o método 3 D. No estudo prospectivo de Deb et al. (2009),11 com 55 mulheres, foram feitas as CFA por dois observadores com três métodos: TSA HDAC chemical structure 2 D em tempo real, 3 D visão multiplanar e Sono AVC. 3-oxoacyl-(acyl-carrier-protein) reductase Concluiu‐se que o Sono AVC com pós‐processamento é um método confiável para medir a CFA total. Mas a CFA pelo Sono AVC leva mais tempo para ser feita por causa da necessidade do processamento posterior e obtém valores que são menores do que os obtidos pelas técnicas 2 D em tempo real e 3 D visão multiplanar. No entanto, a CFA obtida pelo Sono AVC provavelmente é menor porque esse método

estabelece medidas e códigos de cor para cada folículo e impede a recontagem. A CFA feita por observadores, métodos e tempos diferentes está sujeita a uma variação que pode alterar a confiabilidade do exame. Alguns autores propõem que não há diferenças nos resultados quando comparados os métodos ultrassonográficos. Porém, a maioria dos estudos refere que com o modo 2 D a identificação do folículo e a medição de seus diâmetros ocorrem de forma manual e subjetiva, o que permite uma maior variabilidade interobservador. A ultrassonografia 3 D pode, então, melhorar a confiabilidade interobservador da contagem de folículos antrais. O pós‐processamento com possibilidade de recontagem folicular e a reanálise das imagens em outro momento contribuem para essa melhor confiabilidade, mas tendem a aumentar o tempo total do exame. Os autores declaram não haver conflitos de interesse. “
“Entre aproximadamente 40 e 65 anos, as mulheres vivenciam uma fase complexa, denominada climatério, que é uma síndrome com instalação gradual e variada de sintomas.

, 2004),

sad1 in cotton ( Xu, Huang, Wang, Zhang, & Luo, 2006), BnACCg8 in rapeseed ( Hernandez, Rio, Esteve, Prat, & Pla, 2001), papain in papaya ( Xu et al., 2008), the lectin and β-actin genes in the soybean ( James, Schmidt, Wall, Green, & Masri, 2003) and the Ivr1, zein, adh1 and hmg genes in maize ( Hernandez et al., 2004). Scaravelli, Brohée, Marchelli, and Van Hengel Bortezomib mouse (2008) identified a peanut-specific sequence within the Arah3 allergen gene family; the limit of detection using this sequence is as low as 3 pg DNA. Xu et al. (2006) showed that the limit of detection of transgenic papaya using the species-specific gene papain as an endogenous reference is 1 pg of papaya genomic DNA. The endogenous reference gene is critically important in many areas of food products research. Qualitative and quantitative assays using endogenous reference genes can be applied to measure

the quality of DNA sample extraction, determine the food source in case of food allergen mixing, and confirm the relative content of certain species in a complex food matrix. Peach juice LDN-193189 research buy is very popular in the Chinese juice market, and adulteration phenomena are very common. Thus, it is essential to establish a mature biotechnology for the detection of peach juice adulteration. In this paper, an endogenous reference gene for the peach is established, and qualitative and quantitative PCR primers and Taqman probes are designed to detect the specificity and detection limit of the species-specific gene Lhcb2 and

to confirm the gene copy number using the Southern blot method. All fresh fruit varieties were purchased in local markets. The four peach varieties tested were honey peach (Prunus persica (L.) Batsch), nectarine (P. persica var. nectarina), flat peach (P. persica f. compressa) and yellow peach (Amygdalus persica); DNA samples were also collected from the Guoguang apple, Ya pear, navel orange, Kyoho grapes, kiwi fruit, tomato, strawberry and mango. The DNA samples used for qualitative and quantitative PCR detection and Southern blot analysis were extracted according to the CTAB method (Doyle & Doyle, 1990). The Alanine-glyoxylate transaminase fruit samples were mixed with liquid nitrogen and ground into powder, and genomic DNA was isolated from 0.1 g of flesh. After the extraction, the DNA samples were analyzed by 1% agarose gel electrophoresis in 1× TAE containing ethidium bromide. DNA concentrations were determined spectrophotometrically at 260 nm using a UV/VIS spectrometer (Kontron, Neufahrn, Germany). The copy numbers were calculated based on the measured DNA quantity and the average genome size (Arumuganathan & Earle, 1991). DNA samples (10 μg) from two peach varieties were completely digested with HindIII and EcoRI, respectively, under the conditions recommended by the manufacturer (TaKaRa, Tokyo, Japan). Then, the digested sample was resolved in a 0.8% agarose gel with electrophoresis in 1× TBE buffer at a constant voltage of 40 V for 4–5 h.

For the mTOR inhibitor gilthead seabream (Sparus aurata), a fish from the same family which is similar to blackspot seabream in some morphological aspects, five different schemes have emerged. In the first, developed by Huidobro et al. (2000), the QIM has 15 demerit points. Alasalvar, Taylor, Öksüz, Shahidi, and Alexis (2002) described a scheme with 38 demerit points, while Lougovois, Kyranas, and Kyrana (2003) suggested a QIM with 16 demerit points. More recently, Cakli, Kilinc, Dincer & Tolasa (2007) considered again 38 demerit points

as the maximum value for QIM of gilthead seabream. Finally, Nunes, Batista, and Cardoso (2007) presented a scheme for gilthead seabream with 20 demerit points. To develop a QIM scheme for blackspot seabream, the greatest numbers of possible descriptors were chosen. The final scheme suggested in this work includes 30 demerit points, CH5424802 manufacturer describing six quality attributes

with 14 sensory attributes (Table 2). Fig. 1 shows the results of all parameters considered, during the ice storage. Odour, as in many previously published fish sensory schemes, appeared to be one of the quality attributes most influenced by ice storage. At the beginning of the storage time, the skin odour was described as fresh or seaweedy and then the odour became neutral. Around the 12 day, the odour was described as sour milky and during the later stages as metallic. Microbiological analysis of the skin showed that until the 4th day of storage there was no noticeable increase in the numbers of microorganisms Clomifene (Fig. 2). An initial bacterial flora of around 103 cfu/cm2 remained constant along the first 4 days in ice; this could be expected, as as it corresponds to the lag phase of

bacteria growth and changes in this period are mainly attributable to autolytic reactions, enzymatically mediated. After day 4, the bacterial growth became evident (Fig. 2), and on the eighth day there is an increase with values of 105 cfu/cm2 for Pseudomonas while for TVC the values were around 106 cfu/cm2. Pseudomonas and Shewanella putrafaciens have highly specific iron chelating systems (siderophores), but when grown in co-culture on fish samples siderophore producing Pseudomonas inhibits S. putrafaciens ( Gram and Dalgaard, 2002 and Olafsdóttir et al., 2006). After day 8, the growth rate of H2S reducing bacteria is slower, while the growth of Pseudomonas increases rapidly ( Fig. 2). Low molecular weight fatty acids are normally associated with sour odours; Acinobacter and Pseudomonas putida have also been associated with these kinds of odours ( Olafsdóttir and Fleurence, 1997, Sveinsdóttir et al., 2003 and Whitifield, 2003).

It is well established that the prefrontal

cortex undergoes structural and also seemingly functional change with increasing age (see Grady, 2008 for review). Less established are effects on parietal cortex and selleck kinase inhibitor the right hemisphere white matter underlying these regions. However, it appears to be the case that older participants have significantly more activity in posterior parietal cortex whilst attending to an attentional cue (Jimura and Braver, 2010) and a general greater recruitment of these regions in other attention tasks (Grady, 2008). The authors propose that this age group is less efficient at utilizing attention, possibly as a result of loss of capacity (Jimura and Braver, 2010). Structurally, there is evidence of both cortical parietal atrophy (Bergfield et al., 2010) as well as age-related white matter hyperintensities in this region

(Murray et al., 2010). Results found here correspond well with these recent neuroimaging studies as we demonstrate the behavioural consequences of age related degeneration of attentional networks. The results outlined within this paper are important with respect to the groups studied here but beyond that the paradigm itself is a significant development. Our own previous research using a similar paradigm revealed that if task load is high enough even young healthy participants can miss items in the U0126 manufacturer near periphery (Russell et al., 2004 see Lavie, 2005). Further adaptation of the basic method could be used to investigate attentional capacity across diverse groups such as those with left hemisphere damage or suffering from dementia, enabling the identification of the key brain regions and networks for integration of spatial and temporal components of attention. In conclusion, we have examined spatiotemporal attention processing capacity in two groups. The first (Experiment 1) consisted of patients with right hemisphere lesions, without neglect. Compared to Phosphoribosylglycinamide formyltransferase their healthily ageing counterparts,

these individuals suffer from a pathological loss of ability to discriminate simple stimuli even in the near periphery when they complete an unrelated task at screen centre. This loss is modulated by the amount of attention they must give the central task and temporally extends for a period of 850 msec. Secondly (Experiment 2), task modulations made it possible to examine the effects of healthy ageing on visual attention. Here we were able to show that an older group (mean age: 63 years) was as efficient as a much younger group when little attention was required at screen centre. However, they were greatly impaired across the visual field when they were required to allocate more attention centrally. They failed to discriminate simple letters and suffered from an AB of 450 msec.