bluuebunny/crossref_metadata_2025 huggingface dataset:
“Dreams so Big Only the Sea Can Hold Them”: Man-Made Islands as Anxious Spaces, Cultural Icons, and Travelling Visions
Authors: Jackson Mark , della Dora Veronica
Published: June 2009

This paper explores a new phenomenon which is assuming global proportions: the planning and construction of artificial islands. Varying in size, shape, and purpose, man-made islands are looming on the horizons of an increasing number of aspiring global cities and regions at the margins of global capitalism. From the Persian Gulf to the Black Sea, from the Caribbean to the North Sea, artificial islands are increasingly embraced as spectacular, technical signifiers of global participation and urban economic progress: as the ‘new cultural icons’. Appropriated in different contexts, island projects, however, can be (and are) also resignified. They thus change in form, meaning, and use. While islands have been objects of renewed interest in cultural and historical geography, surprisingly, these new man-made landforms seem to have gone largely unnoticed. This paper suggests a research agenda to engage with artificial islands as a new ‘metageographical’ category of emergent, yet historically resonant, social space.
Symmetry and Asymmetry in Working and Commuting Arrangements between Partners in the Netherlands: Does the Residential Context Matter?
Authors: de Meester Edith , van Ham Maarten
Published: June 2009

Time spent on work and commuting within dual-earner households is often analysed separately for individuals, but this does no justice to the reality of dual-earner households where decisions on work and commuting are made in a household context. This paper reports on a quantitative study of the impact of the residential context on working arrangements and commuting arrangements of partners in couple and family households. Using multinomial logistic regression, we analysed data from the 2002 Netherlands Housing Demand Survey and the 2004 ABF Real Estate Monitor. The results show a (gendered) effect of residential location in terms of degree of urbanisation and job access on both working and commuting arrangements. Good access to jobs makes it more likely that couples have a symmetric full-time working arrangement and also more likely that both partners work far away from home. Those in symmetric full-time working arrangements are also those most likely to be in symmetric close commuting arrangements. This finding reflects the substantial time pressure on such households.
Neighbourhood Reputation and the Intention to Leave the Neighbourhood
Authors: Permentier Matthieu , van Ham Maarten , Bolt Gideon
Published: June 2009

Moving intentions are likely to be affected not only by whether or not residents are satisfied with their neighbourhood, but also by how they think that other city residents assess their neighbourhood: the perceived reputation of the neighbourhood. The place where one lives is a reflection of one's position in society and therefore people may want to leave neighbourhoods with a poor reputation even if they are satisfied with their residential environment. Using data from a specifically designed survey in twenty-four Dutch neighbourhoods we tested the hypothesis that, in addition to neighbourhood satisfaction, perceived neighbourhood reputations are an important predictor of the intention to leave a neighbourhood. The results show that perceived neighbourhood reputation is indeed a significant predictor of moving intentions, even after controlling for neighbourhood satisfaction and neighbourhood attachment. This finding suggests that neighbourhood regeneration policy should focus not only on improving residents' neighbourhood satisfaction, but also on improving the perceived reputation of neighbourhoods.
Explaining Sociospatial Patterns in South East Queensland, Australia: Social Homophily versus Structural Homophily
Authors: McCrea Rod
Published: June 2009

Model simulations of residential segregation have shown that even modest levels of social homophily (or wishing to live near residents with similar social characteristics) gives rise to distinct spatial patterns of residential segregation. However, this proposition has been contested where social homophily is modest. This paper contrasts two explanations for urban sociospatial patterns (socioeconomic and demographic spatial patterns) in a region where social homophily is modest-South East Queensland (SEQ). The research question is whether sociospatial patterns are better explained by social homophily or by structural homophily. In other words, are they better explained by residents wishing to live in neighborhoods with similar people (social homophily), or by residents with similar social characteristics finding similar neighborhood physical attributes important, and thus moving to neighborhoods with similar people (structural homophily). SEQ residents were asked how important various reasons were in choosing their neighborhood. The survey data were linked to neighborhood social characteristics from census data with the aid of geographic information systems. Six neighborhood social characteristics in SEQ were investigated. Social homophily explained a small, though statistically significant, level of spatial variation in socioeconomic and ethnic (non-Western) environments. However, it did not explain any variation in the other four neighborhood social characteristics which related to household structure: that is, younger nonnuclear household environments; nuclear family environments; and older nonnuclear household environments, or disadvantaged environments. Moreover, structural homophily explained much more variation than did social homophily in all six neighborhood social characteristics. In regions such as SEQ, spatial patterns can largely be explained by structural homophily. Thus, modest levels of social homophily are not necessarily important in explaining sociospatial patterning.
Two Faces of the Other-Race Effect: Recognition and Categorisation of Caucasian and Chinese Faces
Authors: Ge Liezhong , Zhang Hongchuan , Wang Zhe , Quinn Paul C , Pascalis Olivier , Kelly David , Slater Alan , Tian Jie , Lee Kang
Published: June 2009

The other-race effect is a collection of phenomena whereby faces of one's own race are processed differently from those of other races. Previous studies have revealed a paradoxical mirror pattern of an own-race advantage in face recognition and an other-race advantage in race-based categorisation. With a well-controlled design, we compared recognition and categorisation of own-race and other-race faces in both Caucasian and Chinese participants. Compared with own-race faces, other-race faces were less accurately and more slowly recognised, whereas they were more rapidly categorised by race. The mirror pattern was confirmed by a unique negative correlation between the two effects in terms of reaction time with a hierarchical regression analysis. This finding suggests an antagonistic interaction between the processing of face identity and that of face category, and a common underlying processing mechanism.
Discriminating Audiovisual Speed: Optimal Integration of Speed Defaults to Probability Summation When Component Reliabilities Diverge
Authors: Bentvelzen Adam , Leung Johahn , Alais David
Published: June 2009

We investigated audiovisual speed perception to test the maximum-likelihood-estimation (MLE) model of multisensory integration. According to MLE, audiovisual speed perception will be based on a weighted average of visual and auditory speed estimates, with each component weighted by its inverse variance, a statistically optimal combination that produces a fused estimate with minimised variance and thereby affords maximal discrimination. We use virtual auditory space to create ecologically valid auditory motion, together with visual apparent motion around an array of 63 LEDs. To degrade the usual dominance of vision over audition, we added positional jitter to the motion sequences, and also measured peripheral trajectories. Both factors degraded visual speed discrimination, while auditory speed perception was unaffected by trajectory location. In the bimodal conditions, a speed conflict was introduced (48° versus 60° s−1) and two measures were taken: perceived audiovisual speed, and the precision (variability) of audiovisual speed discrimination. These measures showed only a weak tendency to follow MLE predictions. However, splitting the data into two groups based on whether the unimodal component weights were similar or disparate revealed interesting findings: similarly weighted components were integrated in a manner closely matching MLE predictions, while dissimilarity weighted components (greater than 3: 1 difference) were integrated according to probability-summation predictions. These results suggest that different multisensory integration strategies may be implemented depending on relative component reliabilities, with MLE integration vetoed when component weights are highly disparate.
Multi-decadal increases in shrub abundance in non-riverine red gum (Eucalyptus camaldulensis) woodlands occur during a period of complex land-use history
Authors: Price Jodi N. , Morgan John W.
Published: June 2009

The history of land-use was examined in Eucalyptus camaldulensis Dehnh. woodland in the Victoria Valley of the Grampians National Park, south-eastern Australia, to help interpret changes in vegetation there during the last 50 years. We used aerial photography and dendrochronological data to quantify the amount of, and the rate of change in, the woody-vegetation cover between 1948 and 1997, and historical data to document land-use changes during this time. Aerial photographs indicated that in 1948, 56% of study area had <50% cover of woody plants. By 1997, 90% of the study area had >50% woody-plant cover. The native shrub Leptospermum scoparium J.R. Forst & G. Forst (Myrtaceae) was predominantly responsible for the increases in cover. Demographic analyses indicated that recruitment has been ongoing rather than episodic; large numbers of shrubs, however, have recruited since 1994. We hypothesise that the vegetation changes observed are likely a response to changes in land-use that have occurred since European occupation. Increased woody-plant cover followed the removal of sheep grazing in the long-term absence of fire. It is very likely that the long history of stock grazing, coupled with selective logging and associated soil disturbance, initiated a change in understorey vegetation by reducing competitive native tussock grasses and fuel loads to carry fires and this reduction was initially responsible for the encroachment of shrubs into the woodland. Recruitment has been ongoing in the absence of any recent land-use changes (most utilisation ceasing after the declaration of National Park status in 1984) and hence, this transformation from species-rich herbaceous woodland to shrubby woodland is expected to continue in the future.
Internal secretory spaces in thickened underground systems of Asteraceae species
Authors: Cury Graziela , Appezzato-da-Glória Beatriz
Published: June 2009

Secretory structures are present in many vascular plants and have an important ecological role as a plant defence mechanism against herbivors and pathogens. Internal secretory spaces of lipid substances are widespread in the Asteraceae. However, information about the occurrence of these structures in thickened underground systems is sparse, compared with what we know about aerial systems. The main objective of the present paper was to investigate the occurrence, formation and chemical nature of the secretory structures in six Asteraceae species belonging to the following tribes: Eupatorieae (Mikania cordifolia and M. sessilifolia), Mutisiae (Trixis nobilis), Plucheeae (Pterocaulon alopecuroides) and Vernonieae (Vernonia elegans and V. megapotamica). The samples were collected in areas of Cerrado (tropical savanna) in the state of São Paulo, Brazil. The secretory structures found were cortical canals in roots (T. nobilis, P. alopecuroides, V. elegans and V. megapotamica), cortical cavities in roots (M. cordifolia, M. sessilifolia and P. alopecuroides), cavities in the secondary phloem of roots (T. nobilis), cortical cavities in the xylopodium (M. cordifolia, M. sessilifolia, P. alopecuroides and V. megapotamica) and in the underground stem (T. nobilis), and canals in the secondary xylem in the xylopodium (M. cordifolia and M. sessilifolia). Histochemical tests showed the presence of lipid substances in all structures.
Patterns in vascular plant species density in tall alpine herbfield along an increasing altitudinal gradient in an Australian alpine region
Authors: Pickering Catherine M. , Butler Sarah
Published: June 2009

Patterns in species density and richness per altitudinal interval have been found when sampling across plant-community boundaries, including in the largest contiguous alpine area in Australia. To see if similar patterns occur within a single community, vascular-plant composition was systematically sampled with replicate nested quadrats of increasing size (0.01, 0.06, 0.25, 1.00, 4.00, 25.00, 49.00 and 100-m2 size) sampled from ~1850-m to 2100-m altitude in tall alpine herbfield, Australia. The only significant relationships with altitude were quadratic relationships for the density of herb and graminoid species, with peak density at middle altitudes and a linear decline in total species richness with altitude for 0.06-m2 quadrats. The composition of 100-m2 quadrats was unrelated to altitude when tested with analysis of similarity for total composition, whereas the relationship was significant for growth-forms and the origin (local endemics, Australia endemics and weeds) of species. Location data from this, and 11 other studies were used to compare the species richness of more of the flora (183 species) in 50-m altitudinal bands. There were significant quadratic relationships for total species richness and the number of herb and shrub species, with a peak in richness at ~2000 m. Therefore, altitude does affect species richness overall in this alpine region, although it has only a weak effect on species density within the most common plant community.
The development and characteristics of periderm and rhytidome in Eucalyptus marginata
Authors: O'Gara E. , Howard K. , Colquhoun I. J. , Dell B. , McComb J. , Hardy G. St. E. J.
Published: June 2009

To understand the pathway used by Phytophthora cinnamomi Rands to penetrate the bark of jarrah, the present study describes unwounded periderm and rhytidome development. Periderm formation is described from its initiation in 4-week-old seedlings to the formation of rhytidome in saplings. Periderm in young seedlings consists of a single type of phellem, namely thin-walled suberised cells. In older seedlings where multiple layers of periderm have formed, layers of thick-walled lignified phellem cells in compacted bands alternate with thin-walled suberised cells. Rhytidome formation in older lignotuberous seedlings and in sapling jarrah occurs through the isolation of secondary phloem by periderm. The rhytidome consists of expanded and partially disintegrated secondary phloem tissue sandwiched between layers of phellem cells. Localised periderm formation beneath stomata results in the formation of lenticels, which are ephemeral features. Superficial periderms occur at sites of leaf and shoot abscission, and of lateral shoot emergence. Concealed axillary shoots lack cuticle on emergence. As the trees age, the internal production of lignified and suberised periderm and rhytidome results in an impenetrable barrier to invasion by P. cinnamomi. However, external sites including lenticels and leaf and shoot abscission and emergence areas, all provide points of ingress in unwounded stems.
Wildland surface fire spread modelling, 1990 - 2007. 1: Physical and quasi-physical models
Authors: Sullivan Andrew L.
Published: June 2009

In recent years, advances in computational power have led to an increase in attempts to model the behaviour of wildland fires and to simulate their spread across the landscape. The present series of articles endeavours to comprehensively survey and précis all types of surface fire spread models developed during the period 1990–2007, providing a useful starting point for those readers interested in recent modelling activities. The current paper surveys models of a physical or quasi-physical nature. These models are based on the fundamental chemistry and physics, or physics alone, of combustion and fire spread. Other papers in the series review models of an empirical or quasi-empirical nature, and mathematical analogues and simulation models. Many models are extensions or refinements of models developed before 1990. Where this is the case, these models are also discussed but in much less detail.
Natural variability of the Keetch - Byram Drought Index in the Hawaiian Islands
Authors: Dolling Klaus , Chu Pao-Shin , Fujioka Francis
Published: June 2009

The Hawaiian Islands experience damaging wildfires on a yearly basis. Soil moisture or lack thereof influences the amount and flammability of vegetation. Incorporating daily maximum temperatures and daily rainfall amounts, the Keetch–Byram Drought Index (KBDI) estimates the amount of soil moisture by tracking daily maximum temperatures and rainfall. A previous study found a strong link between the KBDI and total area burned on the four main Hawaiian Islands. The present paper further examines the natural variability of the KBDI. The times of year at which the KBDI is highest, representing the highest fire danger, are found at each of the 27 stations on the island chain. Spectral analysis is applied to investigate the variability of the KBDI on longer time scales. Windward and leeward stations are shown to have different sensitivities to large-scale climatic fluctuations. An El Niño signal displays a strong relationship with leeward stations, when examined with a band-pass filter and with a composite of standardized anomalies. Departure patterns of atmospheric circulations and sea surface temperatures over the North Pacific are investigated for composites of extremely high KBDI values when fire risk is high. The winter, spring, and fall show anomalous surface anticyclonic circulations, surface divergence, and subsidence over the islands for the upper quartile of KBDI. The winter, spring, and fall composites of equatorial sea surface temperatures for the upper quartile of KBDI are investigated for possible links to atmospheric circulations. These analyses are an effort to allow fire managers some lead time in predicting future fire risks.
Florida wildfire activity and atmospheric teleconnections
Authors: Goodrick Scott L. , Hanley Deborah E.
Published: June 2009

Since 1991, the Florida Division of Forestry has been making seasonal fire severity forecasts based on a relationship between area burned in Florida and El Niño–Southern Oscillation (ENSO). The present study extends the original analysis on which these forecasts are based and attempts to augment it with the addition of other patterns of climate variability. Two atmospheric teleconnection patterns, the North Atlantic Oscillation and Pacific–North American pattern, are examined as potential indicators of seasonal and monthly area burned in Florida. Although ENSO was the only climate index to show a significant correlation to area burned in Florida, the Pacific–North American pattern (PNA) is shown to be a factor influencing fire season severity although the relationship is not monotonic and therefore not revealed by correlation analysis.
Traditional fire management: historical fire regimes and land use change in pastoral East Africa
Authors: Butz Ramona J.
Published: June 2009

Although there is considerable research on the ecological effects of fire in sub-Saharan Africa, research on traditional fire practices is very limited and the consequences of substantial changes to historical fire regimes have not been adequately explored. The present paper examines historic and contemporary uses of fire as a land management tool among Maasai pastoralists in northern Tanzania and explores the potential impacts of changing fire management and fire suppression on savanna vegetation. Village members were interviewed about historical and current practices, reasons for burning, the history of land use, and their perceptions of fire. Eight recent burn sites were selected for examination of size, ignition source, and timing of the burn. The Maasai identified eight major reasons for using fire on a landscape scale in savannas and historically used a progression of small fires throughout the dry season as grasses cured to create a fragmented burn pattern and to prevent large, catastrophic late-season fires. Currently, there is little active vegetation management using fire largely owing to federal fire suppression policies, unpredictable rainfall patterns, increasing population pressures, and a subsequent increase in the number of catastrophic accidental fires. Substantial modifications to historical fire regimes could have cascading consequences for savanna health by increasing late-season fuel loads and the occurrence of large, catastrophic fires.
Prediction of fire occurrence from live fuel moisture content measurements in a Mediterranean ecosystem
Authors: Chuvieco Emilio , González Isabel , Verdú Felipe , Aguado Inmaculada , Yebra Marta
Published: June 2009

The present paper presents and discusses the relationships between live Fuel Moisture Content (FMC) measurements and fire occurrence (number of fires and burned area) in a Mediterranean area of central Spain. Grasslands and four shrub species (Cistus ladanifer L., Rosmarinus officinalis L., Erica australis L. and Phillyrea angustifolia L.) were sampled in the field from the spring to the summer season over a 9-year period. Higher seasonal FMC variability was found for the herbaceous species than for shrubs, as grasslands have very low values in summertime. Moisture variations of grasslands were found to be good predictors of number of fires and total burned surface, while moisture variation of two shrubs (C. ladanifer L. and R. officinalis L.) was more sensitive to both the total burned area and the occurrence of large fires. All these species showed significant differences between the FMC of high and low occurrence periods. Three different logistic regression models were built for the 202 periods of analysis: one to predict periods with more and less than seven fires, another to predict periods with and without large fires (>500 ha), and the third to predict periods with more and less than 200 ha burned. The results showed accuracy in predicting periods with a high number of fires (94%), and extensive burned area (85%), with less accuracy in estimating periods with large fires (58%). Finally, empirical functions based on logistic regression analysis were successfully related to fire ignition or potential burned area from FMC data. These models should be useful to integrate FMC measurements with other variables of fire danger (ignition causes, for instance), to provide a more comprehensive assessment of fire danger conditions.
Rapid locating of fire points from Formosat-2 high spatial resolution imagery: example of the 2007 California wildfire
Authors: Liu Cheng-Chien , Wu An-Ming , Yen Sheng-Yun , Huang Chiung-Huei
Published: June 2009

We report the rapid response of Formosat-2 to locate the fire points in the 2007 California wildfire. After examining the Moderate Resolution Imaging Spectrometer (MODIS) image taken and released on 23 October 2007, we used the agility of Formosat-2 to take high spatial resolution images of the wildfire front on its next overpass of the newly burned area. By calculating the local spatial statistics of the near-infrared band, fire points with a scale of a few metres can be accurately identified on the 2-m pan-sharpened Formosat-2 image. The present work suggests that the synergistic operation of MODIS and Formosat-2 would enable the rapid locating of fire points during wildfires.
Which type of mid‐urethral sling procedure should be chosen for treatment of stress urinary incontinance with intrinsic sphincter deficiency? Tension‐free vaginal tape or transobturator tape
Authors: GÜNGÖRDÜK KEMAL , CELEBI IBRAHIM , ARK CEMAL , CELIKKOL OZGU , YILDIRIM GOKHAN
Published: June 2009

Objective. To compare tension‐free vaginal tape (TVT) and transobturator tape (TOT) for surgical treatment of stress urinary incontinence (SUI) with intrinsic sphincter deficiency. Design. Retrospective study. Setting. Gynecology department, Bakirkoy Women and Childrens’ Hospital, Istanbul. Sample. Three hundred women urodynamically diagnosed with stress incontinence with intrinsic sphincter deficiency underwent synthetic mid‐urethral sling procedures (TVT = 180, TOT = 120). Methods. Before the operation, a complete medical history was taken and a gynecologic examination was performed. Subjects with detrusor overactivity or previous sling surgery were excluded. Clinical checkups were conducted at 3, 6, and 12 months, and then annually. Main outcome measures. Intraoperative complications, postoperative complications, and subjective cure rates. Results. There were no significant differences in demographics between the TVT and TOT groups: mean age, parity, body mass index, menopausal status, and hormone replacement therapy. At a mean follow‐up of 31.2±9.1 (range 12–46) months, the overall cure rates were 78.3% for TVT and 52.5% TOT (p<0.0001). The risk of treatment failure in women who received TOT was 4.9 times higher than in women who underwent TVT. There were no significant differences in perioperative and postoperative complication rates between the two groups. Conclusion. TVT appears to be the preferable surgical option for the treatment of SUI with intrinsic sphincter deficiency.
The Voice Handicap Index with post‐laryngectomy male voices
Authors: Evans Eryl , Carding Paul , Drinnan Michael
Published: June 2009

Background: Surgical treatment for advanced laryngeal cancer involves complete removal of the larynx (‘laryngectomy’) and initial total loss of voice. Post‐laryngectomy rehabilitation involves implementation of different means of ‘voicing’ for these patients wherever possible. There is little information about laryngectomees' perception of their changed voice quality and communication status. Surgical voice restoration (SVR) has become the ‘gold standard’ rehabilitation, but there continue to be patients who use other methods of communication. There is no clear evidence comparing patients' perception of their voice handicap across different types of alaryngeal communication.

Aims: To compare the self‐assessed vocal handicap of laryngectomees using SVR with those using non‐SVR methods of post‐laryngectomy communication.

Methods & Procedures: Potential participants were identified from one Head and Neck cancer centre in South Wales. They included both male and female participants using all methods of post‐laryngectomy communication. Each patient's Voice Handicap Index (VHI) score, sub‐set scores, and group means were calculated. Two major confounding factors: age and time since surgery, and communication method (SVR/non‐SVR), were considered to identify factors, other than method of communication, which may influence rehabilitation outcomes.

Outcomes & Results: A total of 71 questionnaires were sent out and 62 (82%) were returned from 35 patients who had undergone SVR and 27 patients who used non‐SVR methods of communication. Of the non‐SVR group, twelve used oesophageal voice, eleven an electrolarynx, two writing and two mouthing for communication. The gender ratio (53:9), age (43–90 years) and time since surgery (1–40 years) were broadly representative of this population, but because of the small number of females, we excluded the women from further analysis. Individual VHI scores ranged from 4 to 106. Both the SVR and non‐SVR group mean scores: 44.7 and 50.9, were within the range of moderately severe voice handicap. There was no significant difference between the groups for total VHI scores or two of the three sub‐domains, nor any significant effect on voice handicap due to the confounding factors assessed: age or time since surgery. The total VHI score was better by 6.5 (− 4.9 to 17.9) points in the SVR group (p = 0.3), probably reflecting the literature reporting superior voice in SVR.

Conclusions & Implications: The data suggest that where patient‐assessed quality of life is concerned, SVR and non‐SVR outcomes are comparable. This is an important consideration when planning and carrying out treatment recommendations. The study has clear clinical implications; understanding the potential of all methods of post‐laryngectomy communication is essential for holistic patient management.
Treatment generalization and executive control processes: Preliminary data from Chinese anomic individuals
Authors: Yeung Olivia , Law Sam‐Po , Yau Monna
Published: June 2009

Background: While various treatment approaches have been shown to be effective in remediating word‐finding difficulties in aphasic individuals, interest has recently been directed at the role of executive functions in affecting treatment outcomes.

Aims: To examine the existence of a possible relationship between treatment generalization and executive control abilities.

Methods & Procedures: An identical treatment protocol using the English alphabet as letter cues to facilitate name retrieval was applied to five Cantonese‐speaking anomic individuals. A series of language and cognitive tasks were administered to help identify which deficit(s) would affect treatment results.

Outcomes & Results: All five participants demonstrated improvement in naming treated items. However, only two subjects with better inhibitory control exhibited significant gains in naming phonologically related untrained items.

Conclusions & Implications: The preliminary results not only converge on current findings of the role of executive functions in rehabilitation results, but also identify in particular how inhibitory control may affect the outcomes of anomia therapy.
Impaired task switching performance in children with dyslexia but not in children with autism
Authors: Poljac Edita , Simon Sanne , Ringlever Linda , Kalcik Dinka , Groen Wouter B. , Buitelaar Jan K. , Bekkering Harold
Published: June 2009

Problems with cognitive control in both autism and dyslexia have already been reported in different studies. The present study specifically examined task-switching performance in children with autism and dyslexia. For this purpose, a multiple-trial paradigm was used with cues for colour- and shape-matching tasks presented before a run of trials. The cue could imply a task switch (when the cue changed the task) or a task repetition (when the cue did not change the task). Both reaction times and error rates were measured for switching, restarting, and general task performance. Participants were children with autism (24) and with dyslexia (25) and healthy controls (27) with normal IQ and ages from 12 to 18 years. The main finding was that while similar switching performance was observed between children with autism and the healthy controls, children with dyslexia showed a significant switch-specific delay relative to both healthy controls and children with autism. Furthermore, no deficit in restarting performance was observed for any of the two patient groups. Finally, additional evidence is provided for a more general deficit in information processing in dyslexia. Our data suggest that children with autism are able to switch between tasks in a similar way as do normally developing children as long as the tasks are unambiguously specified. Furthermore, the data imply switch-specific deficits in dyslexia additionally to the deficits in general information processing already reported in the literature. The implications of our data are further discussed in relation to the interpretation of the Wisconsin Card Sorting Test.
Inhibition of evaluative and perceptual odour–taste learning by attention to the stimulus elements
Authors: Prescott John , Murphy Samantha
Published: June 2009

Pairing of odours and tastes in solution results in the odour taking on the taste's hedonic and perceptual properties. Theoretical accounts of such conditioning propose that the stimulus elements form a configuration with hedonic and/or perceptual properties. One implication of this account is that configural binding may be inhibited by allocation of attention to the individual elements during conditioning (analytical attention). This was tested here by training participants to attend analytically or synthetically during pairing of odours with either sucrose or water. Differential conditioning effects for sucrose- and water-paired odours were seen only in the synthetic group, with sucrose-paired odours increasing in both smelled sweetness and liking. These data support configural models as explanations for these forms of associative learning and emphasize the role of top-down processes in mediating transfer of perceptual and hedonic properties from tastes to odours.
Finding meaning in art: Preferred levels of ambiguity in art appreciation
Authors: Jakesch Martina , Leder Helmut
Published: June 2009

Uncertainty is typically not desirable in everyday experiences, but uncertainty in the form of ambiguity may be a defining feature of aesthetic experiences of modern art. In this study, we examined different hypotheses concerning the quantity and quality of information appreciated in art. Artworks were shown together with auditorily presented statements. We tested whether the amount of information, the amount of matching information, or the proportion of matching to nonmatching statements apparent in a picture (levels of ambiguity) affect liking and interestingness. Only the levels of ambiguity predicted differences in the two dependent variables. These findings reveal that ambiguity is an important determinant of aesthetic appreciation and that a certain level of ambiguity is appreciable.
Microvilli give gut vesicles the brush-off
Authors: Short Ben
Published: June 2009

A surprising new function for intestinal cells in shaping their local environment.
Antonio Giraldez: At the tip of the microRNA iceberg
Authors: Williams Ruth
Published: June 2009

Using zebrafish, Giraldez studies how microRNAs guide the body's development.
Demonstration of catch bonds between an integrin and its ligand
Authors: Kong Fang , García Andrés J. , Mould A. Paul , Humphries Martin J. , Zhu Cheng
Published: June 2009

Binding of integrins to ligands provides anchorage and signals for the cell, making them prime candidates for mechanosensing molecules. How force regulates integrin–ligand dissociation is unclear. We used atomic force microscopy to measure the force-dependent lifetimes of single bonds between a fibronectin fragment and an integrin α5β1-Fc fusion protein or membrane α5β1. Force prolonged bond lifetimes in the 10–30-pN range, a counterintuitive behavior called catch bonds. Changing cations from Ca2+/Mg2+ to Mg2+/EGTA and to Mn2+ caused longer lifetime in the same 10–30-pN catch bond region. A truncated α5β1 construct containing the headpiece but not the legs formed longer-lived catch bonds that were not affected by cation changes at forces <30 pN. Binding of monoclonal antibodies that induce the active conformation of the integrin headpiece shifted catch bonds to a lower force range. Thus, catch bond formation appears to involve force-assisted activation of the headpiece but not integrin extension.
Cholesterol sensor ORP1L contacts the ER protein VAP to control Rab7–RILP–p150Glued and late endosome positioning
Authors: Rocha Nuno , Kuijl Coenraad , van der Kant Rik , Janssen Lennert , Houben Diane , Janssen Hans , Zwart Wilbert , Neefjes Jacques
Published: June 2009

Late endosomes (LEs) have characteristic intracellular distributions determined by their interactions with various motor proteins. Motor proteins associated to the dynactin subunit p150Glued bind to LEs via the Rab7 effector Rab7-interacting lysosomal protein (RILP) in association with the oxysterol-binding protein ORP1L. We found that cholesterol levels in LEs are sensed by ORP1L and are lower in peripheral vesicles. Under low cholesterol conditions, ORP1L conformation induces the formation of endoplasmic reticulum (ER)–LE membrane contact sites. At these sites, the ER protein VAP (VAMP [vesicle-associated membrane protein]-associated ER protein) can interact in trans with the Rab7–RILP complex to remove p150Glued and associated motors. LEs then move to the microtubule plus end. Under high cholesterol conditions, as in Niemann-Pick type C disease, this process is prevented, and LEs accumulate at the microtubule minus end as the result of dynein motor activity. These data explain how the ER and cholesterol control the association of LEs with motor proteins and their positioning in cells.
A genome-wide screen for genes affecting eisosomes reveals Nce102 function in sphingolipid signaling
Authors: Fröhlich Florian , Moreira Karen , Aguilar Pablo S. , Hubner Nina C. , Mann Matthias , Walter Peter , Walther Tobias C.
Published: June 2009

The protein and lipid composition of eukaryotic plasma membranes is highly dynamic and regulated according to need. The sphingolipid-responsive Pkh kinases are candidates for mediating parts of this regulation, as they affect a diverse set of plasma membrane functions, such as cortical actin patch organization, efficient endocytosis, and eisosome assembly. Eisosomes are large protein complexes underlying the plasma membrane and help to sort a group of membrane proteins into distinct domains. In this study, we identify Nce102 in a genome-wide screen for genes involved in eisosome organization and Pkh kinase signaling. Nce102 accumulates in membrane domains at eisosomes where Pkh kinases also localize. The relative abundance of Nce102 in these domains compared with the rest of the plasma membrane is dynamically regulated by sphingolipids. Furthermore, Nce102 inhibits Pkh kinase signaling and is required for plasma membrane organization. Therefore, Nce102 might act as a sensor of sphingolipids that regulates plasma membrane function.
The enterocyte microvillus is a vesicle-generating organelle
Authors: McConnell Russell E. , Higginbotham James N. , Shifrin David A. , Tabb David L. , Coffey Robert J. , Tyska Matthew J.
Published: June 2009

For decades, enterocyte brush border microvilli have been viewed as passive cytoskeletal scaffolds that serve to increase apical membrane surface area. However, recent studies revealed that in the in vitro context of isolated brush borders, myosin-1a (myo1a) powers the sliding of microvillar membrane along core actin bundles. This activity also leads to the shedding of small vesicles from microvillar tips, suggesting that microvilli may function as vesicle-generating organelles in vivo. In this study, we present data in support of this hypothesis, showing that enterocyte microvilli release unilamellar vesicles into the intestinal lumen; these vesicles retain the right side out orientation of microvillar membrane, contain catalytically active brush border enzymes, and are specifically enriched in intestinal alkaline phosphatase. Moreover, myo1a knockout mice demonstrate striking perturbations in vesicle production, clearly implicating this motor in the in vivo regulation of this novel activity. In combination, these data show that microvilli function as vesicle-generating organelles, which enable enterocytes to deploy catalytic activities into the intestinal lumen.
Accuracy and precision in quantitative fluorescence microscopy
Authors: Waters Jennifer C.
Published: June 2009

The light microscope has long been used to document the localization of fluorescent molecules in cell biology research. With advances in digital cameras and the discovery and development of genetically encoded fluorophores, there has been a huge increase in the use of fluorescence microscopy to quantify spatial and temporal measurements of fluorescent molecules in biological specimens. Whether simply comparing the relative intensities of two fluorescent specimens, or using advanced techniques like Förster resonance energy transfer (FRET) or fluorescence recovery after photobleaching (FRAP), quantitation of fluorescence requires a thorough understanding of the limitations of and proper use of the different components of the imaging system. Here, I focus on the parameters of digital image acquisition that affect the accuracy and precision of quantitative fluorescence microscopy measurements.
Distinct cytoplasmic maturation steps of 40S ribosomal subunit precursors require hRio2
Authors: Zemp Ivo , Wild Thomas , O'Donohue Marie-Françoise , Wandrey Franziska , Widmann Barbara , Gleizes Pierre-Emmanuel , Kutay Ulrike
Published: June 2009

During their biogenesis, 40S ribosomal subunit precursors are exported from the nucleus to the cytoplasm, where final maturation occurs. In this study, we show that the protein kinase human Rio2 (hRio2) is part of a late 40S preribosomal particle in human cells. Using a novel 40S biogenesis and export assay, we analyzed the contribution of hRio2 to late 40S maturation. Although hRio2 is not absolutely required for pre-40S export, deletion of its binding site for the export receptor CRM1 decelerated the kinetics of this process. Moreover, in the absence of hRio2, final cytoplasmic 40S maturation is blocked because the recycling of several trans-acting factors and cytoplasmic 18S-E precursor ribosomal RNA (rRNA [pre-rRNA]) processing are defective. Intriguingly, the physical presence of hRio2 but not its kinase activity is necessary for the release of hEnp1 from cytoplasmic 40S precursors. In contrast, hRio2 kinase activity is essential for the recycling of hDim2, hLtv1, and hNob1 as well as for 18S-E pre-rRNA processing. Thus, hRio2 is involved in late 40S maturation at several distinct steps.
Coupling between the voltage-sensing and phosphatase domains of Ci-VSP
Authors: Villalba-Galea Carlos A. , Miceli Francesco , Taglialatela Maurizio , Bezanilla Francisco
Published: June 2009

The Ciona intestinalis voltage sensor–containing phosphatase (Ci-VSP) shares high homology with the phosphatidylinositol phosphatase enzyme known as PTEN (phosphatase and tensin homologue deleted on chromosome 10). We have taken advantage of the similarity between these proteins to inquire about the coupling between the voltage sensing and the phosphatase domains in Ci-VSP. Recently, it was shown that four basic residues (R11, K13, R14, and R15) in PTEN are critical for its binding onto the membrane, required for its catalytic activity. Ci-VSP has three of the basic residues of PTEN. Here, we show that when R253 and R254 (which are the homologues of R14 and R15 in PTEN) are mutated to alanines in Ci-VSP, phosphatase activity is disrupted, as revealed by a lack of effect on the ionic currents of KCNQ2/3, where current decrease is a measure of phosphatase activity. The enzymatic activity was not rescued by the introduction of lysines, indicating that the binding is an arginine-specific interaction between the phosphatase binding domain and the membrane, presumably through the phosphate groups of the phospholipids. We also found that the kinetics and steady-state voltage dependence of the S4 segment movement are affected when the arginines are not present, indicating that the interaction of R253 and R254 with the membrane, required for the catalytic action of the phosphatase, restricts the movement of the voltage sensor.
A structural model for K2P potassium channels based on 23 pairs of interacting sites and continuum electrostatics
Authors: Kollewe Astrid , Lau Albert Y. , Sullivan Ashley , Roux Benoît , Goldstein Steve A.N.
Published: June 2009

K2PØ, the two-pore domain potassium background channel that determines cardiac rhythm in Drosophila melanogaster, and its homologues that establish excitable membrane activity in mammals are of unknown structure. K2P subunits have two pore domains flanked by transmembrane (TM) spans: TM1-P1-TM2-TM3-P2-TM4. To establish spatial relationships in K2PØ, we identified pairs of sites that display electrostatic compensation. Channels silenced by the addition of a charge in pore loop 1 (P1) or P2 were restored to function by countercharges at specific second sites. A three-dimensional homology model was determined using the crystal structure of KV1.2, effects of K2PØ mutations to establish alignment, and compensatory charge–charge pairs. The model was refined and validated by continuum electrostatic free energy calculations and covalent linkage of introduced cysteines. K2P channels use two subunits arranged so that the P1 and P2 loops contribute to one pore, identical P loops face each other diagonally across the pore, and the channel complex has bilateral symmetry with a fourfold symmetric selectivity filter.
Effects of inserting fluorescent proteins into the α1S II–III loop: insights into excitation–contraction coupling
Authors: Bannister Roger A. , Papadopoulos Symeon , Haarmann Claudia S. , Beam Kurt G.
Published: June 2009

In skeletal muscle, intermolecular communication between the 1,4-dihydropyridine receptor (DHPR) and RYR1 is bidirectional: orthograde coupling (skeletal excitation–contraction coupling) is observed as depolarization-induced Ca2+ release via RYR1, and retrograde coupling is manifested by increased L-type Ca2+ current via DHPR. A critical domain (residues 720–765) of the DHPR α1S II–III loop plays an important but poorly understood role in bidirectional coupling with RYR1. In this study, we examine the consequences of fluorescent protein insertion into different positions within the α1S II–III loop. In four constructs, a cyan fluorescent protein (CFP)–yellow fluorescent protein (YFP) tandem was introduced in place of residues 672–685 (the peptide A region). All four constructs supported efficient bidirectional coupling as determined by the measurement of L-type current and myoplasmic Ca2+ transients. In contrast, insertion of a CFP–YFP tandem within the N-terminal portion of the critical domain (between residues 726 and 727) abolished bidirectional signaling. Bidirectional coupling was partially preserved when only a single YFP was inserted between residues 726 and 727. However, insertion of YFP near the C-terminal boundary of the critical domain (between residues 760 and 761) or in the conserved C-terminal portion of the α1S II–III loop (between residues 785 and 786) eliminated bidirectional coupling. None of the fluorescent protein insertions, even those that interfered with signaling, significantly altered membrane expression or targeting. Thus, bidirectional signaling is ablated by insertions at two different sites in the C-terminal portion of the α1S II–III loop. Significantly, our results indicate that the conserved portion of the α1S II–III loop C terminal to the critical domain plays an important role in bidirectional coupling either by conveying conformational changes to the critical domain from other regions of the DHPR or by serving as a site of interaction with other junctional proteins such as RYR1.