bluuebunny/crossref_metadata_2025_split huggingface dataset:
ADAPTABILITY OF IRRIGATED RICE TO TEMPERATURE CHANGE IN SAHELIAN ENVIRONMENTS
Authors: DE VRIES MICHIEL E. , LEFFELAAR PETER A. , SAKANÉ NOMÉ , BADO BOUBIÉ V. , GILLER KEN E. 
Published: January 2011

SUMMARYTo assess genotype adaptability to variable environments, we evaluated five irrigated rice genotypes, three new varieties, WAS161, a NERICA, IR32307 and ITA344, and two controls: Sahel 108, the most popular short-duration variety in the region, and IR64. In a field experiment conducted at two locations, Ndiaye and Fanaye, along the Senegal River, rice was sown on 15 consecutive dates at one month intervals starting in February 2006. Yield (0–12.2 t ha−1) and crop cycle duration (117–190 days) varied with sowing date, genotype and site. Rice yield was very sensitive to sowing date and the associated temperature regimes. Spikelet sterility due to cold stress (T < 20 °C) was observed when the crops were sown in August (Ndiaye), September (Ndiaye and Fanaye) and October (Ndiaye and Fanaye), and heat stress (T > 35 °C) resulted in spikelet sterility when sowing took place in April (Ndiaye and Fanaye) and May (Fanaye). For all experiments the source and sink balance was quantified and showed that yield was most limited by sink size when sowing between July and October. Variety WAS 161 was least affected by genotype × environment interactions, resulting in lower interactive principal component values. An increase in minimum temperature of 3 °C could decrease spikelet sterility from 100 to 45%. These changes in temperature are likely to force rice farmers in the Senegal River to adjust the cropping calendar, e.g. to delay planting or to use heat-tolerant genotypes.
Variational formulation for weakly nonlinear perturbations of ideal magnetohydrodynamics
Authors: HIROTA M. 
Published: January 2011

AbstractA new equation of motion that governs weakly nonlinear phenomena in ideal magnetohydrodynamics (MHDs) is derived as a natural extension of the well-known linearized equation of motion for the displacement field. This derivation is made possible by expanding the MHD Lagrangian explicitly up to third order with respect to the displacement of plasma, which necessitates an efficient use of the Lie series expansion. The resultant equation of motion (i.e. the Euler–Lagrange equation) includes a new quadratic force term which is responsible for various mode–mode coupling due to the MHD nonlinearity. The third-order potential energy serves to quantify the coupling coefficient among resonant three modes and its cubic symmetry proves the Manley–Rowe relations. In contrast to earlier works, the coupling coefficient is expressed only by the displacement vector field, which is already familiar in the linear MHD theory, and both the fixed and free boundary cases are treated systematically.
Reworked late Neogene Austrochlamys anderssoni (Mollusca: Bivalvia) from northern James Ross Island, Antarctica
Authors: Pirrie D. , Jonkers H.A. , Smellie J.L. , Crame J.A. , McArthur J.M. 
Published: January 2011

AbstractWe report on the discovery of a new outcrop of fossiliferous Neogene sediments on northern James Ross Island, northern Antarctic Peninsula. Approximately 100 specimens of the pectinid bivalve Austrochlamys anderssoni (Hennig, 1911) were collected from the permafrost active layer. This bivalve species has a late Miocene to late Pliocene range and has previously been reported from both the glaciomarine Hobbs Glacier Formation and the interglacial Cockburn Island Formation in the James Ross Island area. The localized presence of abundant A. anderssoni within the permafrost suggests that the fossils have been frost heaved from an outcrop of either the Cockburn Island or the Hobbs Glacier formations, originally deposited on northern James Ross Island. The overall shell form, general absence of associated Antarctic Peninsula-derived clasts in the host sediment, and the measured 87Sr/86Sr isotope ratio of the shells (0.709050) which is indistinguishable from that for pectinid bivalves from the Cockburn Island Formation on Cockburn Island (0.709047) suggest that the shells were derived from a unit similar in age to the Cockburn Island Formation. This suggests that the Cockburn Island Formation was originally more laterally extensive than was previously known.
Teaching and learning geriatric medicine
Authors: Singh Inder , Hubbard Ruth E 
Published: January 2011

SummaryPopulations throughout the world are ageing, with the oldest old the most rapidly growing segment of society. Caring for this ageing population, some of whom have multiple chronic and disabling diseases, will be challenging to healthcare systems. Current training programmes are generating relatively low numbers of geriatricians, largely because students and residents lack interest in a career in geriatric medicine. Therefore, specialists in geriatric medicine cannot directly provide care for all older people. There is a responsibility to ensure that successful practices and essential skills are shared.Here we explore negative attitudes towards geriatric medicine and contrast these with factors motivating change. Educational theories are discussed to investigate how processes of learning and the personal development of students can be optimized. An understanding of geriatric medicine is important for undergraduates, postgraduate trainees in geriatric medicine, general practitioners and allied health professionals. The different challenges presented by each group are reviewed, accompanied by recommendations to enhance learning and examples of effective teaching practices.
The politics of health-care reform in the Netherlands since 2006
Authors: Maarse Hans , Paulus Aggie 
Published: January 2011

AbstractThis article comments on Schut and van de Ven's overview of the results of purchaser competition in Dutch health care, which concludes that the glass can be seen as half full or half empty. Although it is true that results have been achieved, we believe that the evidence is incomplete and in some respects flimsy. More importantly, however, Schut and van de Ven neglect the political context of the market reform introduced in 2006. The reform is far from finished and there has been a constant need for political compromise. Optimism about the market's potential also seems to be on the wane. Several insurer and provider initiatives have provoked political resistance. As a result, there are good reasons to argue that the reform's future is uncertain.
Effects of purchaser competition in the Dutch health system: is the glass half full or half empty?
Authors: Schut Frederik T. , van de Ven Wynand P. M. M. 
Published: January 2011

AbstractIn 2006, the Dutch health insurance system was radically reformed to strengthen competition among health insurers as purchasers of health services. This article considers whether purchaser competition has improved efficiency in health-care provision. Although supply and price regulation still dominates the allocation of health services, purchaser competition has already significantly affected the provision of hospital care, pharmaceuticals and primary care, as well as efforts to gather and disseminate information about quality of care. From this perspective, the glass is half full. However, based on the crude performance indicators available, the reforms have not yet demonstrated significant effects on the performance of the Dutch health system. From this perspective the glass is half empty. The article concludes that the effectiveness of purchaser competition depends crucially on the success of ongoing efforts to improve performance indicators, product classification and the risk equalisation scheme.
AMP-activated protein kinase: a cellular energy sensor with a key role in metabolic disorders and in cancer
Authors: Hardie D. Grahame 
Published: January 2011

It is essential to life that a balance is maintained between processes that produce ATP and those that consume it. An obvious way to do this would be to have systems that monitor the levels of ATP and ADP, although because of the adenylate kinase reaction (2ADP↔ATP+AMP), AMP is actually a more sensitive indicator of energy stress than ADP. Following the discoveries that glycogen phosphorylase and phosphofructokinase were regulated by AMP and ATP, Daniel Atkinson proposed that all enzymes at branch points between biosynthesis and degradation would be regulated by adenine nucleotides. This turned out to be correct, but what Atkinson did not anticipate was that sensing of nucleotides would, in most cases, be performed not by the metabolic enzymes themselves, but by a signalling protein, AMPK (AMP-activated protein kinase). AMPK occurs in essentially all eukaryotes and consists of heterotrimeric complexes comprising catalytic α subunits and regulatory β and γ subunits, of which the latter carries the nucleotide-binding sites. Once activated by a metabolic stress, it phosphorylates numerous targets that alter enzyme activity and gene expression to initiate corrective responses. In lower eukaryotes, it is critically involved in the responses to starvation for a carbon source. Because of its ability to switch cellular metabolism from anabolic to catabolic mode, AMPK has become a key drug target to combat metabolic disorders associated with overnutrition such as Type 2 diabetes, and some existing anti-diabetic drugs (e.g. metformin) and many ‘nutraceuticals’ work by activating AMPK, usually via inhibition of mitochondrial ATP production. AMPK activators also potentially have anticancer effects, and there is already evidence that metformin provides protection against the initiation of cancer. Whether AMPK activators can be used to treat existing cancer is less clear, because many tumour cells appear to have been selected for mutations that inactivate the AMPK system. However, if we can identify the various mechanisms by which this occurs, we may be able to find ways of overcoming it.
Assembly and function of the archaeal flagellum
Authors: Ghosh Abhrajyoti , Albers Sonja-Verena 
Published: January 2011

Motility is a common behaviour in prokaryotes. Both bacteria and archaea use flagella for swimming motility, but it has been well documented that structures of the flagellum from these two domains of life are completely different, although they contribute to a similar function. Interestingly, information available to date has revealed that structurally archaeal flagella are more similar to bacterial type IV pili rather than to bacterial flagella. With the increasing genome sequence information and advancement in genetic tools for archaea, identification of the components involved in the assembly of the archaeal flagellum is possible. A subset of these components shows similarities to components from type IV pilus-assembly systems. Whereas the molecular players involved in assembly of the archaeal flagellum are being identified, the mechanics and dynamics of the assembly of the archaeal flagellum have yet to be established. Recent computational analysis in our laboratory has identified conserved highly charged loop regions within one of the core proteins of the flagellum, the membrane integral protein FlaJ, and predicted that these are involved in the interaction with the assembly ATPase FlaI. Interestingly, considerable variation was found among the loops of FlaJ from the two major subkingdoms of archaea, the Euryarchaeota and the Crenarchaeota. Understanding the assembly pathway and creating an interaction map of the molecular players in the archaeal flagellum will shed light on the details of the assembly and also the evolutionary relationship to the bacterial type IV pili-assembly systems.
Studying biomolecular complexes with pulsed electron–electron double resonance spectroscopy
Authors: Reginsson Gunnar W. , Schiemann Olav 
Published: January 2011

The function of biomolecules is intrinsically linked to their structure and the complexes they form during function. Techniques for the determination of structures and dynamics of these nanometre assemblies are therefore important for an understanding on the molecular level. PELDOR (pulsed electron–electron double resonance) is a pulsed EPR method that can be used to reliably and precisely measure distances in the range 1.5–8 nm, to unravel orientations and to determine the number of monomers in complexes. In conjunction with site-directed spin labelling, it can be applied to biomolecules of all sizes in aqueous solutions or membranes. PELDOR is therefore complementary to the methods of X-ray crystallography, NMR and FRET (fluorescence resonance energy transfer) and is becoming a powerful method for structural determination of biomolecules. In the present review, the methods of PELDOR are discussed and examples where PELDOR has been used to obtain structural information on biomolecules are summarized.
Enzymology and ecology of the nitrogen cycle
Authors: Martínez-Espinosa Rosa María , Cole Jeffrey A. , Richardson David J. , Watmough Nicholas J. 
Published: January 2011

The nitrogen cycle describes the processes through which nitrogen is converted between its various chemical forms. These transformations involve both biological and abiotic redox processes. The principal processes involved in the nitrogen cycle are nitrogen fixation, nitrification, nitrate assimilation, respiratory reduction of nitrate to ammonia, anaerobic ammonia oxidation (anammox) and denitrification. All of these are carried out by micro-organisms, including bacteria, archaea and some specialized fungi. In the present article, we provide a brief introduction to both the biochemical and ecological aspects of these processes and consider how human activity over the last 100 years has changed the historic balance of the global nitrogen cycle.
Partial and complete denitrification in Thermus thermophilus: lessons from genome drafts
Authors: Bricio Carlos , Alvarez Laura , Gómez Manuel J. , Berenguer José 
Published: January 2011

We have obtained draft genomic sequences of PD (partial denitrificant) and CD (complete denitrificant) strains of Thermus thermophilus. Their genomes are similar in size to that of the aerobic strains sequenced to date and probably contain a similar megaplasmid. In the CD strain, the genes encoding a putative cytochrome cd1 Nir (nitrite reductase) and ancillary proteins were clustered with a cytochrome c-dependent Nor (nitric oxide reductase), and with genes that are probably implicated in their regulation. The Nar (nitrate reductase) and associated genes were also clustered and located 7 kb downstream of the genes coding for the Nir. The whole nar–nir–nor denitrification supercluster was identified as part of a variable region of a megaplasmid. No homologues of NosZ were found despite nitrogen balance supports the idea that such activity actually exists.
In vitroproof of direct regulation of glutamine synthetase by GlnK proteins in the extreme halophilic archaeonHaloferax mediterranei
Authors: Pedro-Roig Laia , Camacho Mónica , Bonete María José 
Published: January 2011

Haloferax mediterranei is an extreme halophilic micro-organism belonging to the Archaea domain that was isolated from the Santa Pola solar salterns (Alicante, Spain) in 1983. The biochemistry of the proteins involved in nitrogen metabolism is being studied, but the knowledge of their regulation is very scarce at present. The PII superfamily is constituted by major regulators of nitrogen metabolism, which are widespread in prokaryotic and eukaryotic organisms. These trimeric proteins (12 kDa per subunit) have in Escherichia coli long been known to regulate GS (glutamine synthetase) activity via its adenylyltransferase/adenylyl-removing enzyme and, more recently, to be able to interact directly with this enzyme in methanogenic archaea. We have tested the possible role of PII proteins in the regulation of ammonium assimilation in our model organism and the results clearly indicate that the direct influence of GS by PII proteins can also take place in halophilic archaea, starting with the comprehension of nitrogen regulation in those organisms.
Glycomarkers for muscular dystrophy
Authors: Hewitt Jane E. 
Published: January 2011

During the last 10 years it has become apparent that a significant subset of inherited muscular dystrophy is caused by errors in the glycosylation of α-dystroglycan. Many of these dystrophies are also associated with abnormalities of the central nervous system. Dystroglycan has to be fully glycosylated in order bind to its ligands. To date, six genes have been shown to be essential for functional dystroglycan glycosylation and most, if not all, of these genes act in the formation of O-mannosyl glycans. Genetic heterogeneity indicates that other genes are involved in this pathway. Identification of these additional genes would increase our understanding of this specific and essential glycosylation pathway.
Carbohydrate markers of pancreatic cancer
Authors: Szajda Sławomir Dariusz , Waszkiewicz Napoleon , Chojnowska Sylwia , Zwierz Krzysztof 
Published: January 2011

Pancreatic cancer is the fourth most common cause of death from cancer in the world and the sixth in Europe. Pancreatic cancer is more frequent in males than females. Worldwide, following diagnosis of pancreatic cancer, &lt;2% of patients survive for 5 years, 8% survive for 2 years and &lt;50% survive for only approx. 3 months. The biggest risk factor in pancreatic cancer is age, with a peak of morbidity at 65 years. Difficulty in the diagnosis of pancreatic cancer causes a delay in its detection. It is one of the most difficult cancers to diagnose and therefore to treat successfully. Additional detection of carbohydrate markers may offer a better diagnosis of pancreatic cancer. Carbohydrate markers of cancer may be produced by the cancer itself or by the body in response to cancer, whose presence in body fluids suggests the presence and growth of the cancer. The most widely used, and best-recognized, carbohydrate marker of pancreatic cancer is CA 19–9 [CA (carbohydrate antigen) 19–9]. However, the relatively non-specific nature of CA 19–9 limits its routine use in the early diagnosis of pancreatic cancer, but it may be useful in monitoring treatment of pancreatic cancer (e.g. the effectiveness of chemotherapy), as a complement to other diagnostic methods. Some other carbohydrate markers of pancreatic cancer may be considered, such as CEA (carcinoembryonic antigen), CA 50 and CA 242, and the mucins MUC1, MUC2 and MUC5AC, but enzymes involved in the processing of glycoconjugates could also be involved. Our preliminary research shows that the activity of lysosomal exoglycosidases, including HEX (N-acetyl-β-D-hexosaminidase), GAL (β-D-galactosidase), FUC (α-L-fucosidase) and MAN (α-D-mannosidase), in serum and urine may be used in the diagnosis of pancreatic cancer.
Glycosylation changes as important factors for the susceptibility to urinary tract infection
Authors: Taganna Joemar , de Boer Arjen R. , Wuhrer Manfred , Bouckaert Julie 
Published: January 2011

FimH is the type 1 fimbrial tip adhesin and invasin of Escherichia coli. Its ligands are the glycans on specific proteins enriched in membrane microdomains. FimH binding shows high-affinity recognition of paucimannosidic glycans, which are shortened high-mannose glycans such as oligomannose-3 and -5. FimH can recognize equally the (single) high-mannose glycan on uroplakin Ia, on the urinary defence protein uromodulin or Tamm–Horsfall glycoprotein and on the intestinal GP2 glycoprotein present in Peyer's patches. E. coli bacteria may attach to epithelial cells via hundreds of fimbriae in a multivalent fashion. This binding is considered to provoke conformational changes in the glycoprotein receptor that translate into signalling in the cytoplasm of the infected epithelial cell. Bladder cell invasion by the uropathogenic bacterium is the prelude to recurrent and persistent urinary tract infections in humans. Patients suffering from diabetes mellitus are more prone to contract urinary tract infections. In a study of women, despite longer treatments with a more potent antibiotic, these patients also have more often recurrences of urinary tract infections compared with women without diabetes. Type 1 fimbriae are the most important virulence factors used not only for adhesion of E. coli in the urinary tract, but also for the colonization by E. coli in patients with Crohn's disease or ulcerative colitis. It appears that the increased prevalence of urinary tract infections in diabetic women is not the result of a difference in the bacteria, but is due to changes in the uroepithelial cells leading to an increased adherence of E. coli expressing type 1 fimbriae. Hypothetically, these changes are in the glycosylation of the infected cells. The present article focuses on possible underlying mechanisms for glycosylation changes in the uroepithelial cell receptors for FimH. Like diabetes, bacterial adhesion induces apoptosis that may bring the endoplasmic reticulum membrane with immature mannosylated glycoproteins to the surface. Indicatively, clathrin-mediated vesicle trafficking of glucose transporters is disturbed in diabetics, which would interfere further with the biosynthesis and localization of complex N-linked glycans.
Adapting crops to climate change: a summary.
Authors: Reynolds M. P. , Ortiz R. 
Published: January 2011

Abstract

This introductory chapter provides an overview of the topics covered in this book. The 14 chapters are grouped into four major topics: (i) predictions of climate change and its impact on crop productivity; (ii) adapting to biotic and abiotic stresses through crop breeding; (iii) sustainable and resource-conserving technologies for adaptation to and mitigation of climate change; and (iv) new tools for enhancing crop adaptation to climate change.
Scenarios of climate change within the context of agriculture.
Authors: Jarvis A. , Ramirez J. , Anderson B. , Leibing C. , Aggarwal P. 
Published: January 2011

Abstract

This chapter provides an overview of global climate models and their predictions for climate through the 21st century. The review examines the scientific basis of global climate modelling, including the bases for uncertainty in future climate projections. A summary of the Special Report Emissions Scenarios (SRES) is also provided. The current scientific knowledge on climate change points to increases in temperature of 1-3°C to 2050 combined with some complex spatially explicit changes in rainfall. There remains high uncertainty in predictions of extreme events, especially hurricanes. The chapter then looks at the likely impacts of climate change on agricultural productivity, pest and disease prevalence, and CO2-based fertilization. The impacts on crop productivity are likely to be negative. While moderate increases in temperature may bring about moderate increases in productivity, beyond 1°C of warming the literature tends to agree that impacts will be negative. However, possible CO2-fertilization effects may cancel out these losses, although significant debate exists as to the extent of CO2 fertilization to expect. While most literature predicts increases in the prevalence of agricultural pests and diseases, only a handful of studies have quantified possible impacts and further research is needed in this area.