bluuebunny/crossref_metadata_2025_split huggingface dataset:
Replacement of Ser108 in Plasmodium falciparum enolase results in weak Mg(II) binding: role of a parasite‐specific pentapeptide insert in stabilizing the active conformation of the enzyme
Authors: Dutta Sneha , Mukherjee Debanjan , Jarori Gotam K. 
Published: March 2015

A distinct structural feature of Plasmodium falciparum enolase (Pfeno) is the presence of a five amino acid insert ‐104EWGWS108‐ that is not found in host enolases. Its conservation among apicomplexan enolases has raised the possibility of its involvement in some important physiological function(s). Deletion of this sequence is known to lower kcat/Km, increase Ka for Mg(II) and convert dimer into monomers (Vora HK, Shaik FR, Pal‐Bhowmick I, Mout R & Jarori GK (2009) Arch Biochem Biophys 485, 128–138). These authors also raised the possibility of the formation of an H‐bond between Ser108 and Leu49 that could stabilize the apo‐Pfeno in an active closed conformation that has high affinity for Mg(II). Here, we examined the effect of replacement of Ser108 with Gly/Ala/Thr on enzyme activity, Mg(II) binding affinity, conformational states and oligomeric structure and compared it with native recombinant Pfeno. The results obtained support the view that Ser108 is likely to be involved in the formation of certain crucial H‐bonds with Leu49. The presence of these interactions can stabilize apo‐Pfeno in an active closed conformation similar to that of Mg(II) bound yeast enolase. As predicted, S108G/A‐Pfeno variants (where Ser108‐Leu49 H‐bonds are likely to be disrupted) were found to exist in an open conformation and had low affinity for Mg(II). They also required Mg(II) induced conformational changes to acquire the active closed conformational state essential for catalysis. The possible physiological relevance of apo‐Pfeno being in such an active state is discussed.DatabaseEnolase, 2‐phosphoglycerate dehydratase (
EC4.2.1.11)
Dispersal abilities of riverine freshwater mussels influence metacommunity structure
Authors: Schwalb Astrid N. , Morris Todd J. , Cottenie Karl 
Published: March 2015

Summary

Historically, the importance of dispersal ability for the distribution of organisms has often been ignored, partly because of the difficulty of measuring it. Many unionid mussels, which have larvae that are obligate parasites (usually on fish), are endangered and the conservation and management of these mussels depend on knowledge of the main drivers of their distribution.

Metacommunity theory predicts that limited dispersal should weaken the association of community composition with environmental factors. We tested this prediction by comparing the strength of association with environmental factors of (i) mussels with different dispersal abilities based on mobility of known host fish and (ii) mussels with different host infection strategies targeting fish with different mobility.

Mussels with more mobile host fish showed a significantly stronger association with host fish presence and catchment (as a proximate measure for large‐scale differences in environmental conditions or as a spatial component) compared to mussels with less mobile host fish. Our results thus indicate that mussel distribution is more closely linked to host fish for high‐dispersal mussels, which suggests the potential for species sorting. Mussel species with weak dispersal capabilities show the opposite pattern and are therefore less able to colonise all suitable sites (species sorting with limited dispersal). Thus, the absence of mussels does not necessarily indicate unsuitable environmental conditions, but can also be caused by dispersal limitation.

The impact of different host infection strategies was less clear, and differences in responses could be driven by differences in host fish or even habitat specialisation in addition to potential differences in dispersal abilities.

A better knowledge of the dispersal via host fish of unionid mussels and their host infection strategies will be crucial to understanding their metacommunity dynamics, a necessary precursor for effective conservation practices.
Impacts of climate change and management responses in tropical forests depend on complex frugivore‐mediated seed dispersal
Authors: Mokany Karel , Prasad Soumya , Westcott David A. 
Published: March 2015

AbstractAimBiodiversity outcomes under global change will be influenced by a range of ecological processes, and these processes are increasingly being considered in models of biodiversity change. However, the level of model complexity required to adequately account for important ecological processes often remains unclear. Here we assess how considering realistically complex frugivore‐mediated seed dispersal influences the projected climate change outcomes for plant diversity in theAustralianWetTropics (all 4313 species).LocationTheAustralianWetTropics,Queensland,Australia.MethodsWe applied a metacommunity model (M‐SET) to project biodiversity outcomes using seed dispersal models that varied in complexity, combined with alternative climate change scenarios and habitat restoration scenarios.ResultsWe found that the complexity of the dispersal model had a larger effect on projected biodiversity outcomes than did dramatically different climate change scenarios. Applying a simple dispersal model that ignored spatial, temporal and taxonomic variation due to frugivore‐mediated seed dispersal underestimated the reduction in the area of occurrence of plant species under climate change and overestimated the loss of diversity in fragmented tropical forest remnants. The complexity of the dispersal model also changed the habitat restoration approach identified as the best for promoting persistence of biodiversity under climate change.Main conclusionsThe consideration of complex processes such as frugivore‐mediated seed dispersal can make an important difference in how we understand and respond to the influence of climate change on biodiversity.
Agglomeration Externalities and the Productivity of Italian Firms
Authors: Fazio Giorgio , Maltese Enza 
Published: March 2015

AbstractDespite the richness of contributions on the effects of agglomeration on economic activity, the empirical evidence still falls short, especially at the microeconomic level, where they should matter the most. This paper adds to this literature by performing an empirical exploration of the role of Marshallian, Jacobian, and Porterian externalities for the productivity of Italian firms. In particular, a large dataset of small and medium enterprises is first employed to estimate firm‐level total factor productivity (TFP). Then dynamic panel and instrumental variables estimation methods are used to assess the effects of agglomeration externalities. The findings seem to suggest that these effects may vary depending whether the level or growth of TFP is considered. While the first is mostly influenced by the extent of Marshallian economies, the latter is higher when Jacobian and Porterian economies are at work.
Recreational Housing and Community Development: A Triple Bottom Line Approach
Authors: Winkler Richelle , Deller Steven , Marcouiller Dave 
Published: March 2015

AbstractIn this study, we explore the impact of recreational housing on community development within a triple bottom line (economic, social, environmental) framework. We empirically assess the relationships between recreational housing and social, environmental, and economic conditions in nonmetropolitan counties and explicitly model spatial relationships, considering the potential for indirect spillover effects of recreational housing presence in one county to be associated with social, environmental, and economic conditions in neighboring counties. We employ a spatial Bayesian model averaging method to determine the set of control variables and find that higher concentrations of recreational homes are associated with lower levels of economic well‐being, but somewhat higher levels of environmental quality.
Active surveillance for clinically localized renal tumors: An updated review of current indications and clinical outcomes
Authors: Borghesi Marco , Brunocilla Eugenio , Volpe Alessandro , Dababneh Hussam , Pultrone Cristian Vincenzo , Vagnoni Valerio , La Manna Gaetano , Porreca Angelo , Martorana Giuseppe , Schiavina Riccardo 
Published: March 2015

AbstractThe widespread use of abdominal imaging has led to an increasing detection of small renal masses, and approximately 20–30% of those tumors will prove to be benign, with low metastatic potential if not immediately treated. In elderly or comorbid patients diagnosed with small renal masses, competing cause mortality seems to exceed cancer‐specific mortality at short‐ and intermediate‐term follow up. In these cases, surgery might represent an overtreatment, and an expectant management, such as active surveillance, might be proposed. According to the current available evidence, active surveillance is a safe and reasonable option for patients with renal tumors ≤4 cm (cT1a) and short life expectancy. A few studies with short‐term follow up reported the preliminary results of active surveillance even in cT1b–cT2 tumors, with acceptable risk of disease progression and mortality, even if this approach should be considered in this setting only for highly‐selected and well‐informed patients. Furthermore, surveillance protocols can be proposed in selected patients with uncomplicated benign tumors, such as angiomyolipomas, in which active surveillance should be considered the initial standard management. At present, reliable clinical predictors of a tumor's growth rate and aggressiveness are not available. Renal tumor biopsy is useful in the clinical work‐up of patients who are candidates for active surveillance, in order to improve patient selection based on tumor histological characterization. Despite the proof of safety offered by expectant management for small renal masses in selected patients, further prospective studies with longer follow up are required in order to confirm the indications and long‐term oncological outcomes of active surveillance protocols for renal tumors.
A new species of the enigmatic archosauromorph Doswellia from the Upper Triassic Bluewater Creek Formation, New Mexico, USA
Authors: HECKERT ANDREW B. , LUCAS SPENCER G. , SPIELMANN JUSTIN A. 
Published: March 2015

Abstract:  Doswellia sixmilensis is a new species of the doswelliid archosauromorph genus Doswellia named for an incomplete skeleton from the Upper Triassic Bluewater Creek Formation of the Chinle Group in west‐central New Mexico, USA. D. sixmilensis differs from D. kaltenbachi Weems, the type and only other known species of Doswellia, in its larger size, higher tooth count and greater heterodonty, possession of keels on the cervical centra and the presence of discrete knobs or spikes on some osteoderms. The holotype of D. sixmilensis is the fourth occurrence of Doswellia and only the second occurrence of a Doswellia skull, which includes the previously unknown premaxilla and maxilla (and therefore the best dentition) and has the best‐preserved cervical vertebrae. Although it adds to our knowledge of the anatomy of Doswellia, this new information does not alter previous concepts of the phylogenetic relationships of the doswelliid genera, largely because they are so poorly known anatomically. The genus Doswellia is known from the Newark Supergroup in Virginia, and the Chinle Group in Texas, New Mexico and Utah, in strata of Otischalkian–Adamanian age. The type locality of D. sixmilensis is c. 43 m stratigraphically below a bed from which U‐Pb dating of detrital zircons yields a maximum depositional age of c. 220 Ma, so this is a reasonable approximate numerical age for D. sixmilensis.
Garnet–chloritoid–kyanite assemblages: eclogite facies indicators of subduction constraints in orogenic belts
Authors: SMYE A. J. , GREENWOOD L. V. , HOLLAND T. J. B. 
Published: March 2015

AbstractThe assemblage garnet–chloritoid–kyanite is shown to be quite common in high‐pressure eclogite facies metapelites from orogenic belts around the world, and occurs over a narrowly restricted range of temperature ∼550–600 °C, between 20 and 25 kbar. This assemblage is favoured particularly by large Al2O3:K2O ratios allowing the development of kyanite in addition to garnet and chloritoid. Additionally, ferric iron and manganese also help stabilize chloritoid in this assemblage. Pseudosections for several bulk compositions illustrate these high‐pressure assemblages, and a new thermodynamic model for white mica to include calcium and ferric iron was required to complete the calculations. It is extraordinary that so many orogenic eclogite facies rocks, both mafic eclogites sensu stricto as well as metapelites with the above assemblage, all yield temperatures within the range of 520–600 °C and peak pressures ∼23±3 kbar. Subduction of oceanic crust and its entrained associated sedimentary material must involve the top of the slab, where mafic and pelitic rocks may easily coexist, passing through these P–T conditions, such that rocks, if they proceed to further depths, are generally not returned to the surface. This, together with the tightly constrained range in peak temperatures which such eclogites experience, suggests thermal weakening being a major control on the depths at which crustal material is decoupled from the downgoing slab.
Occurrence and Emplacement of Chromite Ores in Sindhudurg District, Maharashtra, India
Authors: IYER Sridhar D. , BABU Elapavalooru V.S.S.K. , MISLANKAR Premchand G. , GUJAR Anup R. , AMBRE Navso V. , LOVESON Victor J. 
Published: March 2015

Abstract:In the present study, we present the occurrence and emplacement of chromite ore deposits from two abandoned mines (Kankavali [Janoli] and Wagda) in the Sindhudurg district of Maharashtra, India. These ores, that occurred as lenses and are associated with metamorphic and ultrabasic rocks, consist of octahedral grains of chromite, while clinochlore is present between the interstices of these grains. The Kankavali (Janoli) and Wagda ores revealed a dominance of Cr2O3 followed by FeO and variable proportions of A12O3, MgO, and SiO2. The former deposits have a slightly higher Cr2O3 (average 52 wt%) and FeO (∼18 wt%) than those from Wagda (Cr2O3∼50 wt%, FeO ∼25 wt%). The similar Cr# values (0.73 for Kankavali [Janoli], 0.74 for Wagda) correspond to those reported for typical podiform‐type chromite deposits. We suggest that the ores were emplaced as phacoliths in folded outcrops with a steep easterly dip and a northwest–southeast trend. We postulate the continuation of the fold structure from Janoli to Wagda (∼4.5 km apart) and the probable (sporadic) occurrence of chromite along this stretch. The possibility of the contribution of chromite grains from these areas to the coastal placer deposits cannot be ruled out.
Neoproterozoic Mafic Dykes and Basalts in the Southern Margin of Tarim, Northwest China: Age, Geochemistry and Geodynamic Implications
Authors: ZHANG Chuanlin , YANG Dongsheng , WANG Hongyan , DONG Yongguan , YE Haimin 
Published: March 2015

Abstract:Neoproterozoic rifting‐related mafic igneous rocks are widely distributed both in the northern and southern margins of the Tarim Block, NW China. Here we report the geochronology and systematic whole‐rock geochemistry of the Neoproterozoic mafic dykes and basalts along the southern margin of Tarim. Our zircon U‐Pb age, in combination with stratigraphic constraint on their emplacement ages, indicates that the mafic dykes were crystallized at ca. 802 Ma, and the basalt, possibly coeval with the ca. 740 Ma volcanic rocks in Quruqtagh in the northern margin of Tarim. Elemental and Nd isotope geochemistry of the mafic dykes and basalts suggest that their primitive magma was derived from asthenospheric mantle (OIB‐like) and lithospheric mantle respectively, with variable assimilation of crustal materials. Integrating the data supplied in the present study and that reported previously in the northern margin of Tarim, we recognize two types of mantle sources of the Neoproterozoic mafic igneous rocks in Tarim, namely the matasomatized subcontinental lithospheric mantle (SCLM) in the northern margin and the long‐term enriched lithospheric mantle and asthenospheric mantle in the southern margin. A comprehensive synthesis of the Neoproterozoic igneous rocks throughout the Tarim Block led to the recognition of two major episodes of Neoproterozoic igneous activities at ca. 820–800 Ma and ca. 780–740 Ma, respectively. These two episodes of igneous activities were concurrent with those in many other Rodinian continents and were most likely related to mantle plume activities during the break‐up of the Rodinia.
Petrology, Mineralogy and Geochemisty of Antarctic Mesosiderite GRV 020175: Implications for Its Complex Formation History
Authors: WANG Linyan , HSU Weibiao , MA Changqian 
Published: March 2015

Abstract:GRV 020175 is an Antarctic mesosiderite, containing about 43 vol% silicates and 57 vol% metal. Metal occurs in a variety of textures from irregular large masses, to veins penetrating silicates, and to matrix fine grains. The metallic portion contains kamacite, troilite and minor taenite. Terrestrial weathering is evident as partial replacement of the metal and troilite veins by Fe oxides. Silicate phases exhibit a porphyritic texture with pyroxene, plagioclase, minor silica and rare olivine phenocrysts embedded in a fine‐grained groundmass. The matrix is ophitic and consists mainly of pyroxene and plagioclase grains. Some orthopyroxene phenocrysts occur as euhedral crystals with chemical zoning from a magnesian core to a ferroan overgrowth; others are characterized by many fine inclusions of plagioclase composition. Pigeonite has almost inverted to its orthopyroxene host with augite lamellae, enclosed by more magnesian rims. Olivine occurs as subhedral crystals, surrounded by a necklace of tiny chromite grains (about 2–3 μm). Plagioclase has a heterogeneous composition without zoning. Pyroxene geothermometry of GRV 020175 gives a peak metamorphic temperature (∼1000°C) and a closure temperature (∼875°C). Molar Fe/Mn ratios (19–32) of pyroxenes are consistent with mesosiderite pyroxenes (16–35) and most plagioclase compositions (An87.5–96.6) are within the range of mesosiderite plagioclase grains (An88–95). Olivine composition (Fo53.8) is only slightly lower than the range of olivine compositions in mesosiderites (Fo55–90). All petrographic characteristics and chemical compositions of GRV 020175 are consistent with those of mesosiderite and based on its matrix texture and relatively abundant plagioclase, it can be further classified as a type 3A mesosiderite. Mineralogical, petrological, and geochemical studies of GRV 020175 imply a complex formation history starting as rapid crystallization from a magma in a lava flow on the surface or as a shallow intrusion. Following primary igneous crystallization, the silicate underwent varying degrees of reheating. It was reheated to 1000°C, followed by rapid cooling to 875°C. Subsequently, metal mixed with silicate, during or after which, reduction of silicates occurred; the reducing agent is likely to have been sulfur. After redox reaction, the sample underwent thermal metamorphism, which produced the corona on the olivine, rims on the inverted pigeonite phenocrysts and overgrowths on the orthopyroxene phenocrysts, and homogenized matrix pyroxenes. Nevertheless, metamorphism was not extensive enough to completely reequilibrate the GRV 020175 materials.
Minimum Bedrock Exposure Ages and Their Implications: Larsemann Hills and Neighboring Bolingen Islands, East Antarctica
Authors: HUANG Feixin , LI Guangwei , LIU Xiaohan , KONG Ping , JU Yitai , FINK David , FANG Aimin , YU Liangjun 
Published: March 2015

Abstract:Considerable controversy exists over whether or not extensive glaciation occurred during the global Last Glacial Maximum (LGM) in the Larsemann Hills. In this study we use the in situ produced cosmogenic nuclide 10Be (half life 1.51 Ma) to provide minimum exposure ages for six bedrock samples and one erratic boulder in order to determine the last period of deglaciation in the Larsemann Hills and on the neighboring Bolingen Islands. Three bedrock samples taken from Friendship Mountain (the highest peak on the Mirror Peninsula, Larsemann Hills; ∼2 km from the ice sheet) have minimum exposure ages ranging from 40.0 to 44.7 ka. The erratic boulder from Peak 106 (just at the edge of the ice sheet) has a younger minimum exposure age of only 8.8 ka. The minimum exposure ages for two bedrock samples from Blundell Peak (the highest peak on Stornes Peninsula, Larsemann Hills; ∼2 km from the ice sheet) are about 17 and 18 ka. On the Bolingen Islands (southwest to the Larsemann Hills; ∼10 km from the ice sheet), the minimum exposure age for one bedrock sample is similar to that at Friendship Mountain (i.e., 44 ka). Our results indicate that the bedrock exposure in the Larsemann Hills and on the neighboring Bolingen Islands commenced obviously before the global LGM (i.e., 20–22 ka), and the bedrock erosion rates at the Antarctic coast areas may be obviously higher than in the interior land.
Synthesis and Growth Mechanism of TiC Whiskers by Carbothermal Reduction of Titania/Microcrystalline Cellulose
Authors: Xiong Huiwen , Li Zhiyou , Zhou Kechao 
Published: March 2015

TiC whiskers were synthesized by a typical chloride‐assisted carbothermal reduction method using microcrystalline cellulose as a novel carbon source. Unlike previous research, Faceted TiC whiskers on the titanium oxide particles (Ti3O5) were epitaxially grown via vapor–solid mechanism without catalyst. Liquid–liquid separation was used for product purification. A 90–95 vol% yield of TiC whiskers was observed, with 0.5 μm in diameter and 40–60 μm in length. X‐ray diffraction study indicated that the lattice parameter of TiC increased (from 4.288 to 4.321 Å) with increasing the C/Ti ratio and sintering temperature. Preferred growth was found to be the [100] direction from the lattice‐resolved imaging. This study provided not only a new simple method for synthesizing TiC whiskers but also a new insight into the growth mode for TiC whiskers.
Three Aristotelian Accounts of Disease and Disability
Authors: Glackin Shane N. 
Published: March 2015

AbstractThe question of whether medical and psychiatric judgements involve a normative or evaluative component has been a source of wide and vehement disagreement. But among those who think such a component is involved, there is considerable further disagreement as to its nature. In this article, I consider several versions of Aristotelian normativism, as propounded by Christopher Megone, Michael Thompson and Philippa Foot, and Martha Nussbaum. The first two, I claim, can be persuasively rebutted by different modes of liberal pluralist challenge — respectively, pluralism about structures of social organisation and pluralism about biological forms. Nussbaum's version, by contrast, is alert to the need for pluralism; I argue, however, that the Aristotelian aspects of her theory hamper her pursuit of those pluralistic aims.