bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of glaciers on streamflow trends in the Swiss Alps
Authors: Pellicciotti F. , Bauder A. , Parola M.
Published: October 2010

Daily streamflow from stations close to five Swiss glaciers is analyzed for trends with the Mann‐Kendall test. We consider a common period of record (1974–2004) and longer periods based on data availability. The trend statistical significance is tested on annual and seasonal bases. We also examine changes in precipitation, temperature, and snow cover characteristics. Highly glacierized basins show statistically significant positive trends in annual streamflow caused by increasing streamflow in spring and summer. Trends are more numerous and stronger at lower and mid than at the upper quantiles. The basin characterized by lower glacier coverage, conversely, does not exhibit consistently statistically significant trends. Changes in precipitation are not sufficient to explain the observed streamflow trends. Air temperature sees an increase in mean, minimum, and maximum values at all sites. Variations in the seasonal snow accumulation and ablation process are evident. Solid precipitation is decreasing at all sites and trends may be due to a shift from snowfall into rainfall. Mean snow depth is also decreasing, and its duration is getting shorter because of a decrease in solid precipitation and enhanced melting. Trend magnitude attenuates with longer time series. Contrasting trends are detected for different subperiods in the last 70 years: statistically significant negative trends are observed in the periods 1944–1974 and 1954–1984 for Aletschgletscher, in contrast with the results for the common period. These trends are explained by different rates of ice volume changes, and the sign of trends is clearly related to phases of positive or negative glacier mass balance.
Enhanced ocean temperature forecast skills through 3‐D super‐ensemble multi‐model fusion
Authors: Lenartz F. , Mourre B. , Barth A. , Beckers J.‐M. , Vandenbulcke L. , Rixen M.
Published: October 2010

An innovative multi‐model fusion technique is proposed to improve short‐term ocean temperature forecasts: the three‐dimensional super‐ensemble. In this method, a Kalman Filter is used to adjust three‐dimensional model weights over a past learning period, allowing to give more importance to recent observations, and take into account spatially varying model skills. The predictive performance is evaluated against SST analyses, CTD casts and gliders tracks collected during the Ligurian Sea Cal/Val 2008 experiment. Statistical results not only show a very significant bias reduction of this multi‐model forecast in comparison with the individual models, their ensemble mean and a single‐weight‐per‐model version of the super‐ensemble, but also the improvement of other pattern‐related skills. In a 48‐h forecast experiment, and with respect to the ensemble mean, surface and subsurface root‐mean‐square differences with observations are reduced by 57% and 35% respectively, making this new technique a suitable non‐intrusive post‐processing method for multi‐model operational forecasting systems.
A multi‐decadal delay in the onset of corrosive ‘acidified’ waters in the Ross Sea of Antarctica due to strong air‐sea CO2 disequilibrium
Authors: McNeil Ben I. , Tagliabue Alessandro , Sweeney Colm
Published: October 2010

Antarctic coastal waters have an abundance of marine organisms that secrete the mineral aragonite for growth and survival. Increasing oceanic anthropogenic CO2 uptake will push these waters to a point whereby aragonite will start to geochemically corrode, with direct consequences for the Antarctic ecosystem. Here we combine surface CO2 data in the Ross Sea, Antarctica with a regional ocean/sea‐ice model to better pinpoint the timing of corrosive conditions. Our analysis suggests sea‐ice cover and deep‐water entrainment during winter results in 65% lower storage of anthropogenic CO2 in comparison to atmospheric CO2 equilibrium. This means that instead of corrosive ‘acidified’ waters beginning as early as the winter of 2015, anthropogenic CO2 disequilibrium delays its onset by up to 30 years, giving this Antarctic marine ecosystem a several decade reprieve to corrosive conditions. Our results demonstrate a broader importance of understanding natural oceanic carbon cycle variability for the onset of corrosive conditions.
Record warming in the South Pacific and western Antarctica associated with the strong central‐Pacific El Niño in 2009–10
Authors: Lee Tong , Hobbs William R. , Willis Joshua K. , Halkides Daria , Fukumori Ichiro , Armstrong Edward M. , Hayashi Akiko K. , Liu W. Timothy , Patzert William , Wang Ou
Published: October 2010

Satellite data for the past three decades reveal a record‐high sea surface temperature (SST) anomaly within a large mid‐latitude region of the south‐central Pacific (SCP) during the mature phase of the 2009–10 El Niño, with a peak magnitude that is 5 times the standard deviation of local SST anomaly and is warmer than the concurrent tropical‐Pacific SST anomaly. The SCP oceanic warming was confined to the upper 50 meters and is associated with an extreme and persistent anticyclone. Wind changes associated with the anticyclone caused the oceanic warming with surface heat flux and ocean processes playing equally important roles. The anticyclone diverted circumpolar westerlies and warm air towards Antarctica. Austral‐summer SST in the Bellingshausen Sea also reached a three‐decade high. The extreme atmospheric and oceanic anomalies in the South Pacific may have been fueled by the 2009–10 El Niño because of its record‐high SST anomaly in the central‐equatorial Pacific.
Estimating seismic moment magnitude (Mw) of tremor bursts in northern Cascadia: Implications for the “seismic efficiency” of episodic tremor and slip
Authors: Kao Honn , Wang Kelin , Dragert Herb , Kao Jason Y. , Rogers Garry
Published: October 2010

We develop a method to estimate the seismic moments of deep non‐volcanic tremor bursts observed in northern Cascadia. For each tremor burst, the maximum amplitudes at individual stations within a time window ±5 s around the predicted arrivals of the S phase are measured and compared to the maximum S amplitudes measured from synthetic seismograms. The proposed method is thoroughly calibrated using 464 local earthquakes and the results show excellent consistency between the reported ML and the estimated Mw. We apply the method to northern Cascadia tremors and infer that most bursts have Mw∼1.0–1.7. The corresponding b value appears to be 1, consistent with that of ordinary earthquakes but over a narrower Mw range. Comparison of cumulative tremor Mw and the Mw estimated from the accompanying slow slip suggests that the “seismic efficiency” of the Episodic Tremor and Slip (ETS) is of the order of 0.1% or less.
Quasistatic electric field structures and field‐aligned currents in the polar cusp region
Authors: Jacobsen K. S. , Moen J. I. , Pedersen A.
Published: October 2010

Cluster data have been examined for quasi‐stationary electric field structures and field‐aligned currents (FACs) in the vicinity of the dayside cusp region. We have related the measurements to the Region 1/Region 2 (R1/R2) current system and the cusp current system. It has been theoretically proposed that the dayside R1 current may be located on open field lines, and experimental evidence has been shown for R1 currents partially on open field lines. We document that R1 currents may flow entirely on open field lines. The electric field structures are found to occur at plasma density gradients in the cusp. They are associated with strong FACs with current directions that are consistent with the cusp currents. This indicates that the electric field structures are closely coupled to the cusp current system. The electric equipotential structures linking the perpendicular electric fields seen at Cluster altitudes to field‐aligned electric fields at lower altitudes fall into one of two categories: S shape or U shape. Both types are found at both the equatorward edge of the cusp ion dispersion and at the equatorward edge of injection events within the cusp. Previous studies in the nightside auroral region attributed the S‐shaped potential structures to the boundary transition between the low‐density polar cap and the high‐density plasma sheet, concluding that the shape of the electric potential structure depends on whether the plasma populations on each side of the structure can support intense currents. This explanation is not applicable for the S‐shaped structures observed in the dayside cusp region.
Polar cap electric field saturation during interplanetary magnetic field Bz north and south conditions
Authors: Wilder F. D. , Clauer C. R. , Baker J. B. H.
Published: October 2010

We report the results of an investigation of the saturation of the polar cap electric field during periods of large northward and southward interplanetary magnetic field (IMF). While it has been demonstrated that saturation can occur for both northward and southward IMF, a direct comparison between the two regimes during saturated driving has not been performed. We use solar wind measurements to search for events between 1998 and 2007 when the IMF is stable for 50 min. The selected intervals are binned according to interplanetary electric field (−VSW × B). SuperDARN Doppler radar velocity vectors from high‐latitude antisunward looking beams are averaged to determine the approximate polar cap electric field. Results show that sunward convection under northward IMF is stronger in summer than in winter, but that antisunward convection under southward IMF exhibits the opposite seasonal behavior. One explanation is that, as the earth tilts near solstice, lobe reconnection is less effective in the winter hemisphere.
Low‐energy electrons in Saturn's inner magnetosphere and their role in interchange injections
Authors: DeJong A. D. , Burch J. L. , Goldstein J. , Coates A. J. , Young D. T.
Published: October 2010

Since the days of Pioneer 11 and the Voyager missions, electrons have shown an unexplained peak in the data at approximately 7.5 Saturn radii (RS). To investigate this peak, we examine near‐equatorial electron energy flux data (±10°) from the Cassini Plasma Spectrometer Electron Spectrometer from 1 July 2004 through 10 August 2007. When these data are plotted versus L shell, a peak between L = 7.5 and L = 8 appears in the electron data in the 12–100 eV range. We show that this peak is associated with interchange injections. The electrons are separated into trapped (70°–110°) pitch angles and field‐aligned (0°–20° and 160°–180°) pitch angles. The field‐aligned electrons show stronger fluxes than the trapped electrons in the 12–100 eV range during these injections. In SLS3 coordinates, the trapped electrons peak at longitudes between 45° and 240° at 7–8 RS with a smaller peak occurring between 310° and 360° SLS3 longitudes that penetrates to 6–5 RS. The field‐aligned electrons, however, show no SLS3 dependence.
Observations and modeling of the ionospheric behaviors over the east Asia zone during the 22 July 2009 solar eclipse
Authors: Le Huijun , Liu Libo , Ding Feng , Ren Zhipeng , Chen Yiding , Wan Weixing , Ning Baiqi , Xu Guirong , Wang Min , Li Guozhu , Xiong Bo , Hu Lianhuan
Published: October 2010

The longest total solar eclipse during the 21st century with a maximum duration of 6 min and 39 s occurred in South and East Asia on 22 July 2009. The TEC data from four GPS stations in the total eclipse region (around 30°N) from 105°E to 135°E are used to study the variation in TEC. Height profiles of electron density from Formosa3/Cosmic satellites are used to study the height dependence of the electron density response. We also modeled the eclipse effects on the ionosphere by an ionospheric model. Both the observations from F3/C and the modeled results show that there is an overall decrease in the electron density below F2 region, with the largest relative decrease occurring at F1 region. The TEC observations show the delay time of the largest TEC decrease at the total eclipse region with regard to the maximum obscuration is less than five minutes and smaller than what is estimated from the time constant of the plasma loss rate at the F2 peak altitude although main contribution to TEC comes from the plasma density in the F2 region. The modeling study shows that, due to the large plasma flux from topside ionosphere to F2 layer, the TEC response around 30°N is mainly due to the electron density response at low altitudes (E and F1 region, 200 km below) where the time delay of electron density response is very short (less than 4 min). Thus the time delay of TEC response would also be short as observed by GPS TEC.
Midlatitude daytime D region ionosphere variations measured from radio atmospherics
Authors: Han Feng , Cummer Steven A.
Published: October 2010

We measured the midlatitude daytime ionospheric D region electron density profile height variations in July and August 2005 near Duke University by using radio atmospherics (or sferics for short), which are the high‐power, broadband very low frequency (VLF) signals launched by lightning discharges. As expected, the measured daytime D region electron density profile heights showed temporal variations quantitatively correlated with solar zenith angle changes. In the midlatitude geographical regions near Duke University, the observed quiet time heights decreased from ∼80 km near sunrise to ∼71 km near noon when the solar zenith angle was minimum. The measured height quantitative dependence on the solar zenith angle was slightly different from the low‐latitude measurement given in a previous work. We also observed unexpected spatial variations not linked to the solar zenith angle on some days, with 15% of days exhibiting regional differences larger than 0.5 km. In these 2 months, 14 days had sudden height drops caused by solar flare X‐rays, with a minimum height of 63.4 km observed. The induced height change during a solar flare event was approximately proportional to the logarithm of the X‐ray flux. In the long waveband (wavelength, 1–8 Å), an increase in flux by a factor of 10 resulted in 6.3 km decrease of the height at the flux peak time, nearly a perfect agreement with the previous measurement. During the rising and decaying phases of the solar flare, the height changes correlated more consistently with the short, rather than the long, wavelength X‐ray flux changes.
Resveratrol Attenuates Oxidized LDL-Evoked Lox-1 Signaling and Consequently Protects against Apoptotic Insults to Cerebrovascular Endothelial Cells
Authors: Chang Huai-Chia , Chen Tyng-Guey , Tai Yu-Ting , Chen Ta-Liang , Chiu Wen-Ta , Chen Ruei-Ming
Published: October 2010

Cerebrovascular endothelial cells (CECs) are crucial components of the blood—brain barrier. Our previous study showed that oxidized low-density lipoprotein (oxLDL) induces apoptosis of CECs. This study was designed to further evaluate the effects of resveratrol on oxLDL-induced CEC insults and its possible molecular mechanisms. Resveratrol decreased the oxidation of LDL into oxLDL. Additionally, the oxLDL-caused oxidative stress and cell damage were attenuated by resveratrol. Exposure of CECs to oxLDL induced cell shrinkage, DNA fragmentation, and cell apoptosis, but resveratrol defended against such injuries. Application of Lox-1 small interference (si)RNA into CECs reduced the translation of this membrane receptor, and simultaneously increased resveratrol protection from oxLDL-induced cell apoptosis. By comparison, overexpression of Lox-1 attenuated resveratrol protection. Resveratrol inhibited oxLDL-induced Lox-1 mRNA and protein expressions. Both resveratrol and Lox-1 siRNA decreased oxLDL-enhanced translocation of proapoptotic Bcl-2-associated X protein (Bax) from the cytoplasm to mitochondria. Sequentially, oxLDL-induced alterations in the mitochondrial membrane potential, cytochrome c release, and activities of caspases-9, -3, and -6 were decreased by resveratrol. Pretreatment with Z-VEID-FMK (benzyloxycarbonyl-Leu-Glu-His-Asp-fluoromethyl ketone) synergistically promoted resveratrol's protection against DNA fragmentation and cell apoptosis. Therefore, this study shows that resveratrol can protect CECs from oxLDL-induced apoptotic insults via downregulating Lox-1-mediated activation of the Bax-mitochondria—cytochrome c—caspase protease pathway.
Estrogen Enhances Neurogenesis and Behavioral Recovery after Stroke
Authors: Li Jun , Siegel Matt , Yuan Mike , Zeng Zhiyuan , Finnucan Laura , Persky Rebecca , Hurn Patricia D , McCullough Louise D
Published: October 2010

Stroke is a leading cause of permanent disability and death. It is well accepted that the principal mammalian estrogen (E2), 17-β estradiol, provides robust neuroprotection in a variety of brain injury models in animals of both sexes. E2 enhances neurogenesis after stroke in the subventricular zone; however, it is unknown if these cells survive long-term or enhance functional recovery. In this study, we examined stroke-induced neurogenesis in male, gonadally intact female, and ovariectomized female mice 2 and 6 weeks after stroke. Treatment with 17-β estradiol increased 5-bromo-2′-deoxyuridine-labeled cells at both time points in both the dentate gyrus and subventricular zone; the majority were colabeled with doublecortin at 2 weeks and with NeuN at 6 weeks. Stroke-induced neurogenesis was reduced in estrogen receptor knockout mice, as well as in mice lacking the gene for aromatase, which converts testosterone into E2. Improved behavioral deficits were seen in E2-treated mice, suggesting that E2-induced increases in poststroke neurogenesis contribute to poststroke recovery.
Mycobacterium tuberculosis WhiB1 is an essential DNA-binding protein with a nitric oxide-sensitive iron–sulfur cluster
Authors: Smith Laura J. , Stapleton Melanie R. , Fullstone Gavin J. M. , Crack Jason C. , Thomson Andrew J. , Le Brun Nick E. , Hunt Debbie M. , Harvey Evelyn , Adinolfi Salvatore , Buxton Roger S. , Green Jeffrey
Published: October 2010

Mycobacterium tuberculosis is a major pathogen that has the ability to establish, and emerge from, a persistent state. Wbl family proteins are associated with developmental processes in actinomycetes, and M. tuberculosis has seven such proteins. In the present study it is shown that the M. tuberculosis H37Rv whiB1 gene is essential. The WhiB1 protein possesses a [4Fe-4S]2+ cluster that is stable in air but reacts rapidly with eight equivalents of nitric oxide to yield two dinuclear dinitrosyl-iron thiol complexes. The [4Fe-4S] form of WhiB1 did not bind whiB1 promoter DNA, but the reduced and oxidized apo-WhiB1, and nitric oxide-treated holo-WhiB1 did bind to DNA. Mycobacterium smegmatis RNA polymerase induced transcription of whiB1 in vitro; however, in the presence of apo-WhiB1, transcription was severely inhibited, irrespective of the presence or absence of the CRP (cAMP receptor protein) Rv3676, which is known to activate whiB1 expression. Footprinting suggested that autorepression of whiB1 is achieved by apo-WhiB1 binding at a region that overlaps the core promoter elements. A model incorporating regulation of whiB1 expression in response to nitric oxide and cAMP is discussed with implications for sensing two important signals in establishing M. tuberculosis infections.
Soil characteristics of Rocky Mountain National Park grasslands invaded by Melilotus officinalis and M. alba
Authors: Wolf J. J. , Beatty S. W. , Seastedt T. R.
Published: October 2010

Aim  Invasion of nitrogen‐fixing non‐native plant species may alter soil resources and impact native plant communities. Altered soils may be the driving mechanism that provides a suitable environment to facilitate future invasions and decrease native biodiversity. We hypothesized that Melilotus invasion would increase nitrogen availability and produce soil microclimate and biochemical changes, which could in turn alter plant species composition in a montane grassland community.

Location  Our research addressed the effects of white and yellow sweet clover (Melilotus officinalis and M. alba) invasion on soil characteristics and nitrogen processes in the montane grasslands in Rocky Mountain National Park.

Methods  We sampled soil in replicate sites of Melilotus‐invaded and control (non‐invaded) patches within disturbed areas in montane grassland habitats. Soil composites were analysed for available nitrogen, net nitrogen mineralization, moisture, carbon/nitrogen (C : N ratio), texture, organic matter and pH. Data were recorded at three sample dates during the growing seasons of 1998 and 1999.

Results  Contrary to our expectations, we observed lower nitrogen availability and mineralization in invaded patches, and differences in soil moisture content and soil C : N. Soil C : N ratios were higher in invaded plots, in spite of the fact that Melilotus had the lowest C : N ratios of other plant tissue analysed in this study.

Main conclusions  These findings provide land managers of natural areas with a better perspective on the possibilities of nitrogen‐fixing species impact on soil nutrient levels.
Floristic biogeography of the Hawaiian Islands: influences of area, environment and paleogeography
Authors: Price Jonathan P.
Published: October 2010

Aim  A detailed database of distributions and phylogenetic relationships of native Hawaiian flowering plant species is used to weigh the relative influences of environmental and historical factors on species numbers and endemism.

Location  The Hawaiian Islands are isolated in the North Pacific Ocean nearly 4000 km from the nearest continent and nearly as distant from the closest high islands, the Marquesas. The range of island sizes, environments, and geological histories within an extremely isolated archipelago make the Hawaiian Islands an ideal system in which to study spatial variation in species distributions and diversity. Because the biota is derived from colonization followed by extensive speciation, the role of evolution in shaping the regional species assemblage can be readily examined.

Methods  For whole islands and regions of each major habitat, species–area relationships were assessed. Residuals of species–area relationships were subjected to correlation analysis with measures of endemism, isolation, elevation and island age. Putative groups of descendents of each colonist from outside the Hawaiian Islands were considered phylogenetic lineages whose distributions were included in analyses.

Results  The species–area relationship is a prominent pattern among islands and among regions of each given habitat. Species number in each case correlates positively with number of endemics, number of lineages and number of species per lineage. For mesic and wet habitat regions, island age is more influential than area on species numbers, with older islands having more species, more single‐island endemics, and higher species : lineage ratios than their areas alone would predict.

Main conclusions  Because species numbers and endemism are closely tied to speciation in the Hawaiian flora, particularly in the most species‐rich phylogenetic lineages, individual islands’ histories are central in shaping their biota. The Maui Nui complex of islands (Maui, Moloka‘i, Lāna‘i and Kaho‘olawe), which formed a single large landmass during most of its history, is best viewed in terms of either the age or area of the complex as a whole, rather than the individual islands existing today.
Animal species diversity driven by habitat heterogeneity/diversity: the importance of keystone structures
Authors: Tews J. , Brose U. , Grimm V. , Tielbörger K. , Wichmann M. C. , Schwager M. , Jeltsch F.
Published: October 2010

Aim In a selected literature survey we reviewed studies on the habitat heterogeneity–animal species diversity relationship and evaluated whether there are uncertainties and biases in its empirical support.

Location World‐wide.

Methods We reviewed 85 publications for the period 1960–2003. We screened each publication for terms that were used to define habitat heterogeneity, the animal species group and ecosystem studied, the definition of the structural variable, the measurement of vegetation structure and the temporal and spatial scale of the study.

Main conclusions The majority of studies found a positive correlation between habitat heterogeneity/diversity and animal species diversity. However, empirical support for this relationship is drastically biased towards studies of vertebrates and habitats under anthropogenic influence. In this paper, we show that ecological effects of habitat heterogeneity may vary considerably between species groups depending on whether structural attributes are perceived as heterogeneity or fragmentation. Possible effects may also vary relative to the structural variable measured. Based upon this, we introduce a classification framework that may be used for across‐studies comparisons. Moreover, the effect of habitat heterogeneity for one species group may differ in relation to the spatial scale. In several studies, however, different species groups are closely linked to ‘keystone structures’ that determine animal species diversity by their presence. Detecting crucial keystone structures of the vegetation has profound implications for nature conservation and biodiversity management.
Recent spread of Dracophyllum scrub on subantarctic Campbell Island, New Zealand: climatic or anthropogenic origins?
Authors: Wilmshurst Janet M. , Bestic Kim L. , Meurk Colin D. , McGlone Matt S.
Published: October 2010

Aim  The vegetation of subantarctic Campbell Island consists mainly of lowland Dracophyllum scrub and upland tussock grassland and tundra. Soon after the island was discovered in 1810, occupation by sealers and whalers led to localized burning and cutting of scrub. Further burning and cutting took place as a result of sheep farming between 1894 and 1931. Since the earliest photographs and vegetation descriptions of the island in the late nineteenth century, scrub cover has expanded markedly. Also, since the 1960s, the island has become warmer and drier. The aim of this paper is to quantify scrub changes as depicted in photo‐sequences from the island, and to establish if the spread of scrub is a result of the cessation of anthropogenic activities or a response to global warming.

Location  Campbell Island, an isolated island 600 km south of New Zealand mainland (52°33.7′S, 169°09′E).

Methods  Changes in scrub cover in the island were established through analysis of 33 photographic sequences in the island, the earliest photos dating back to 1888. Visual estimates were made of percentage woody cover in matching areas of repeat photographs, and of changes in scrub distribution with altitude and landscape type.

Results  Dracophyllum scrub was restricted at the time of the first photographs (1888) relative to its present extent, and earlier written observations suggest that there had been little change from the 1840s. Scrub cover has subsequently increased in most areas. Most of the spread occurred after the cessation of farming. Change has mostly consisted of a thickening and expansion of pre‐existing scrub patches. There is no indication that the upper elevational limit of scrub has increased.

Main conclusions  Initial reduction of scrub was probably due to anthropogenic fire in the early nineteenth century, although it is possible that less favourable climates had also restricted its distribution. Failure of the scrub to regenerate significantly between 1840 and c. 1895 may also have been a consequence of generally cooler, wetter climates at this time. Rapid scrub expansion began between the end of farming and burning in 1931 and 1988 when the remaining feral sheep were removed. Sheep grazing in the absence of fire reduced competition, and encouraged regeneration and growth of woody scrub. Spread was probably assisted by a pronounced shift to warmer, drier climates in the second half of the twentieth century. Upper elevational limits of scrub have not increased, suggesting that factors other than summer temperature are controlling scrub line in this superoceanic environment.
Using the clinical question to teach search strategy: fostering transferable conceptual skills in user education by active learning
Authors: SNOWBALL ROBIN
Published: October 2010

The three‐ or four‐part clinical question, developed by Dr Scott Richardson for work in evidence‐based health care, is used at the Cairns Library in Oxford to further develop traditional teaching of search preparation for database search training. The process of setting a clear search question, breaking it into search concepts, and then trying out a range of search terms for each major concept, fits elegantly into the framework of the clinical question, with its ‘anatomy’ of Patient/Problem, Intervention/Exposure (two for a comparison search), and Clinical Outcomes. It forces searchers to produce or refine a complete question if they do not have one already, and then to build up a search strategy, using free text or controlled vocabulary search terms, truncation or wildcards, Boolean operators and so on, in stages appropriate to need and to the specific learning situation, which can be ‘tested’ in the search, and refined. It is therefore a flexible teaching and learning tool, which can be used prior to and during searching. It enables user education to focus on fostering system‐independent, transferable conceptual skills, rather than teaching particular databases in isolation, and it lends itself to using active learning strategies in information skills training.
Effective use of health care information
Authors: MERRY PETER
Published: October 2010

A new book commissioned by the British Library looks at research in thejeld and highlights opportunities for health care librarians. The author, Peter Merry, is a freelance consultant editor and writer, and editor of the NHS Confederation's NHS Handbook.
Rain forest expansion mediated by successional processes in vegetation thickets in the Western Ghats of India
Authors: Puyravaud Jean‐Philippe , Dufour Céline , Aravajy Subramanian
Published: October 2010

Aim The objective of this study was to document succession from grassland thickets to rain forest, and to provide evidence for their potential as restoration tools.

Location The Linganamakki region (State of Karnataka) of the Central Western Ghats of India.

Method We selected thirty vegetation thickets ranging from 4 to 439 m2 in area in the vicinity of rain forest. The area of each small thicket was estimated as an oval using its maximum length and its maximum width. When the shape was irregular (mostly in large thickets) the limits of the thicket were mapped and the area calculated from the map. Plant species were identified, the number of individuals was estimated and their heights measured.

Results There was a progression in the thickets from early to late successional species. Small thickets were characterized by ecotone species and savanna trees such as Catunaregam dumetorum. Savanna trees served as a nucleus for thicket formation. Colonizing species were mostly bird‐dispersed. As succession proceeded in larger thickets, the proportion of evergreen, late‐successional rain forest trees increased. The species composition of the large thickets differed depending on the species composition of reproductive adults in the nearby forested areas. The species within small thickets were also found in the large thickets. The nestedness in species composition suggested that species turnover was deterministic based on thicket size. Human disturbance (leaf and wood collection by the local populations) affected the species composition and the species–area relationship of thickets.

Main conclusions Vegetation thickets are nodal centres for rain forest colonization within grasslands. They expand and replace savanna. Early successional bird‐dispersed species established around savanna trees followed by late‐successional rain forest trees dispersed from the nearby forest by birds. Restoration programmes that reproduce natural successional processes such as those observed in thickets will be more successful and less expensive than the methods currently being employed, where trees are individually planted in grassland. Wood harvesting is the only factor that prevents thicket growth and coalescence and hampers forest expansion.
Older species: a rejuvenation on coral reefs?
Authors: Briggs John C.
Published: October 2010

Aim  To discuss the theory that the present high species diversity and apomorphic character of the coral reef ecosystem is because of the historic accumulation of basal species from marginal habitats.

Location  The Indo‐West Pacific Ocean.

Methods  The examination of biogeographical patterns from the standpoint of paleontology, phylogeny, genetics, and empirical data.

Results  Fossil patterns from several clades indicate a gradient of increasing average generic age that extends outward from the high diversity reefs. Successful species that give rise to new species, genera, and families apparently originate from high diversity locations. The tropics have been a major source of evolutionary novelty, not simply a refuge that has accumulated diversity. Many plesiomorphic clades, that once dominated the shallow tropics, are now limited to the deep sea and other safe places. Recent research on several tropical fish families indicates that more apomorphic species inhabit the high diversity reefs. Genetic studies suggest that a decrease in genetic variation extends from the diversity centre toward the outer reaches of the Indo‐West Pacific. Empirical data show that it is extremely difficult for species from low diversity areas to invade places of higher diversity.

Main conclusions  There is no convincing evidence to indicate that basal species from marginal habitats have been able to accumulate on the coral reefs. Once such species have been displaced from a high diversity environment, there is apparently no return. The evolutionary innovations that contribute to the origination of new phyletic lines take place under conditions of high diversity and maximum competition.
Late Quaternary paleoecology from fossil beetle communities in the Awatere Valley, South Island, New Zealand
Authors: Marra Maureen , Leschen Richard A. B.
Published: October 2010

Aim  The research aim is to reconstruct last glacial maximum (LGM) and Holocene vegetation history and ecology from fossil beetle assemblages.

Location  The LGM and Holocene sites are located in the Awatere Valley, which lies in the tectonically active Marlborough Region in the north east of the South Island of New Zealand.

Methods  Beetle fossils were extracted from silty organic sediment using the standard kerosene flotation method. Fossils were identified by comparisons made to modern species based on morphology and surface features. The ecology and distribution of modern analogues are extrapolated to reconstruct the fossil environment.

Results  One hundred and forty‐five beetle species belonging to 33 families were identified. The LGM fossil fauna showed the local vegetation was characterized by a forest patch surrounded by an open tussock/grassland landscape. This Nothofagus (southern beech) forest persisted at the site until mid‐Holocene when it was replaced by a podocarp forest that contained high beetle diversity. Herbivores dominate in the early stage of this zone, indicating a relatively new forest environment. Later in the Holocene, the fauna is dominated by detritivores indicating an older more established forest. The late Holocene is characterized by low diversity and the absence of forest species. This fauna indicates that by 500 years ago, the forest was absent and is associated with an almost compete loss of beetle biodiversity.

Main conclusions  The fossil beetles provide a unique perspective into the past environment in the Awatere Valley on a local scale. The reconstruction supports regional pollen interpretations of Holocene vegetation by identifying a specific forest patch. Fossil beetles are thus a valuable local proxy for vegetation reconstructions.
Trends in butterfly species richness in response to the peninsular effect in South Korea
Authors: Choi Sei‐Woong
Published: October 2010

Aim  The Korean peninsula is elongated in shape and is connected to the Asian continent on the north. The peninsular effect – a decline in species density or richness as a function of distance from the mainland base (towards the distal tip) of a peninsula – was evaluated for plants and animals in different peninsulas. The aims of the present study were to describe the pattern of butterfly species diversity and to determine what factors may be responsible for this pattern along the Korean peninsula. The distribution pattern of butterfly species in South Korea before and after the Korean War was also investigated.

Location  South Korea (34–38° N, 126–129° E).

Methods  Forty‐three quadrats, each 1/2° latitude by 1/2° longitude, and three data sets – butterfly distribution data from 1938 to 1950, butterfly distribution data from 1976 to 1999, and the combined data – were analysed. The influence of four variables – latitude, longitude, area and maximum altitude – on each quadrat was investigated using multiple regression analysis.

Results and conclusion  The analyses revealed a marked peninsular effect: there was a significant positive correlation between butterfly species richness and latitude. Additionally, habitat diversity, expressed as maximum altitude, was significantly correlated with butterfly species richness. I conclude that both the geographical orientation and habitat diversity contribute to butterfly species diversity across South Korea. Comparison of ranges between the older and recent data sets suggests that geographical distributions of several species are dramatically reduced in size. These species may be used for future conservation activities in South Korea.
The uncertain blitzkrieg of Pleistocene megafauna
Authors: Brook Barry W. , Bowman David M. J. S.
Published: October 2010

We investigated, using meta‐analysis of empirical data and population modelling, plausible scenarios for the cause of late Pleistocene global mammal extinctions. We also considered the rate at which these extinctions may have occurred, providing a test of the so‐called ‘blitzkrieg’ hypothesis, which postulates a rapid, anthropogenically driven, extinction event. The empirical foundation for this work was a comprehensive data base of estimated body masses of mammals, comprising 198 extinct and 433 surviving species > 5 kg, which we compiled through an extensive literature search. We used mechanistic population modelling to simulate the role of human hunting efficiency, meat off‐take, relative naivety of prey to invading humans, variation in reproductive fitness of prey and deterioration of habitat quality (due to either anthropogenic landscape burning or climate change), and explored the capacity of different modelling scenarios to recover the observed empirical relationship between body mass and extinction proneness. For the best‐fitting scenarios, we calculated the rate at which the extinction event would have occurred. All of the modelling was based on sampling randomly from a plausible range of parameters (and their interactions), which affect human and animal population demographics. Our analyses of the empirical data base revealed that the relationship between body mass and extinction risk relationship increases continuously from small‐ to large‐sized animals, with no clear ‘megafaunal’ threshold. A logistic ancova model incorporating body mass and geography (continent) explains 92% of the variation in the observed extinctions. Population modelling demonstrates that there were many plausible mechanistic scenarios capable of reproducing the empirical body mass–extinction risk relationship, such as specific targeting of large animals by humans, or various combinations of habitat change and opportunistic hunting. Yet, given the current imperfect knowledge base, it is equally impossible to use modelling to isolate definitively any single scenario to explain the observed extinctions. However, one universal prediction, which applied in all scenarios in which the empirical distribution was correctly predicted, was for the extinctions to be rapid following human arrival and for surviving fauna to be suppressed below their pre‐‘blitzkrieg’ densities. In sum, human colonization in the late Pleistocene almost certainly triggered a ‘blitzkrieg’ of the ‘megafauna’, but the operational details remain elusive.
Use of arboreal and terrestrial space by a small mammal community in a tropical rain forest in Borneo, Malaysia
Authors: Wells Konstans , Pfeiffer Martin , Lakim Maklarin B. , Linsenmair K. Eduard
Published: October 2010

Aim  Small mammals were live‐trapped in a primary rain forest to evaluate the relative distribution of species to each other and to microhabitat properties on the ground and in the canopy.

Location  Kinabalu National Park in Borneo, Sabah, Malaysia.

Methods  Seven trapping sessions were conducted along two grids with 31 trap points at distances of 20 m on the ground and in the lower canopy at an average height of 13.5 m.

Results  Species diversity and abundance of small mammals proved to be high: 20 species of the families Muridae, Sciuridae, Tupaiidae, Hystricidae, Viverridae and Lorisidae were trapped, with murids being dominant in both habitat layers. The terrestrial community was significantly more diverse with 16 captured species (Shannon–Wiener's diversity index  = 2.47), while 11 species were trapped in the canopy ( = 1.59). The Whitehead's rat, Maxomys whiteheadi, and the red spiny rat, Maxomys surifer, dominated the terrestrial community whereas the large pencil‐tailed tree mouse, Chiropodomys major, was by far the most abundant species in the canopy. Other abundant species of the canopy community, the dark‐tailed tree rat, Niviventer cremoriventer, and the lesser treeshrew, Tupaia minor, were also abundant on the ground, and there was no clear boundary between arboreal and terrestrial species occurrences.

Main conclusions  As most species were not confined to specific microhabitats or habitat layers, species seemed to rely on resources not necessarily restricted to certain microhabitats or habitat layers, and separation of species probably resulted mainly from a species’ concentrated activity in a preferred microhabitat rather than from principal adaptations to certain habitats. Ecological segregation was stronger in the more diverse terrestrial community, though microhabitat selection was generally not sufficient to explain the co‐occurrences of species and the variability between local species assemblages. Constraints on small mammal foraging efficiency in the three‐dimensional more complex canopy may be responsible for the similarity of microhabitat use of all common arboreal species. Community composition was characterized by mobile species with low persistence rates, resulting in a high degree of variability in local species assemblages with similar turnover rates in both habitats.
Expression of G protein α subunits in the lateral wall of the rat cochlea
Authors: Khan Khalid M. , Sarfaraz Noorjehan , Siddiqui Sammer , Malik Zainab A. , Salim Zeenat
Published: October 2010

Expression of five G protein α subunits was investigated in the rat cochlea by reverse transcription‐polymerase chain reaction (RT‐PCR) in order to understand their role in the cochlear signal transduction mechanisms. Immunohistochemical techniques were employed to study their distribution in the lateral wall of the cochlea. Total RNA was extracted with guanidine thiocyanate from cochleas and brains of 14–21‐day‐old rats. The extract was treated with DNase to degrade genomic DNA. After RT, the resulting cDNA was amplified by PCR using primers specific for the nucleotide sequences representing α subunits of heterotrimeric G proteins. The results indicated that mRNA for all five α subunits was expressed in the brain and cochlear samples. For immunohistochemical localization, temporal bones of 6‐week‐old rats were fixed in 4% paraformaldehyde and 0.1% glutaraldehyde and processed for embedding in paraffin wax. The dewaxed, midmodiolar sections of the cochlea were incubated with subunit‐specific polyclonal antibodies. The pattern of immunoreactivity varied for the five G protein α subunits studied in the stria vascularis and spiral ligament. The significance of these findings and the role of G protein α subunits in cochlear fluid homeostasis are discussed.
Muscle fibre breakdown in venom‐induced muscle degeneration
Authors: Harris J. B. , Vater R. , Wilson M. , Cullen M. J.
Published: October 2010

We studied the early stages of the degeneration of skeletal muscles using the venom of Notechis scutatus as the myotoxic agent. The venom was used at a dose equivalent to the LD50 in the mouse. There was no mortality amongst the rats. Electron microscopy was used to show the progressive hypercontraction of sarcomeres and the loss of alignment of myofibrils in individual muscle fibres. Between areas of hypercontraction sarcomeres were torn, shedding loosened myofilaments into the cytosol. Western blotting and Coomassie staining were used to compare the respective rates of loss of desmin, titin, actin, myosin and dystrophin. We showed that desmin and titin were the first proteins to be degraded with a time to 50% loss of approximately 1 h and 3 h, respectively. The loss of major contractile proteins, myosin and actin, was rather slower. The loss of dystrophin was also slower than the loss of desmin and titin. Early damage to the plasma membrane of the muscle fibre caused the cells to depolarize, probably promoting the hypercontraction of the sarcomeres, but actual loss of membrane was incomplete even at 24 h. We suggest that the early degradation of desmin and titin was responsible for the disaggregation of the sarcomeres; the liberated contractile proteins myosin and actin were shed into the cytosol, where they were degraded. Phagocytic cells that had invaded the degenerating muscle fibres were primarily involved in the clearance of damaged mitochondria.
Pollical oblique ligament in humans and non‐human primates
Authors: Shrewsbury Marvin
Published: October 2010

A morphological study of the oblique ligament in the thumb is presented. The ligament was consistently described in human specimens and compared with dissections of non‐human primates from different species. The oblique ligament was found in some, but not all, specimens in each of the following species examined: chimpanzee, orang‐utan, gibbon, anubis baboon, hamadryas baboon, squirrel monkey, lemur and marmoset. A revised identity of the oblique ligament is proposed as a reinforced distal border of a fibro‐osseous annular pollical flexor sheath and whose function is not independent of the flexor sheath. The constant presence and tendinous trait of the pollical oblique ligament in humans, when compared with non‐human primates, supports the notion that the oblique ligament strengthens the pollical flexor sheath in humans for restraint of the flexor pollicis longus tendon during forceful precision pinching. A derivation of the pollical oblique ligament is considered as representing a vestigial radial limb of a flexor pollicis superficialis tendon in the thumb.