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Sufficient Number (sufficient + number)
Selected AbstractsMarket Liberalisation, Vertical Integration and Price Behaviour in Tanzania's Coffee AuctionDEVELOPMENT POLICY REVIEW, Issue 2 2001Anna A. Temu Whether market liberalisation can promote agricultural development in Africa depends on how well existing institutions can facilitate trade by private agents. This article assesses the performance of the Tanzania coffee marketing system after liberalisation and the emergence of private, vertically integrated exporters (VIEs). Increasing producer prices, declining marketing margins, and the continued provision of a useful auction for coffee that is delivered by traders who are not VIEs all suggest a degree of success for liberalisation. The presence of VIEs seems to have provided investment to reduce marketing costs, whilst a sufficient number of competing firms has limited non-competitive behaviour in the market for coffee that is traded at the auction by non-VIEs. [source] The Power of the Last Word in Legislative Policy MakingECONOMETRICA, Issue 5 2006B. Douglas Bernheim We examine legislative policy making in institutions with two empirically relevant features: agenda setting occurs in real time and the default policy evolves. We demonstrate that these institutions select Condorcet winners when they exist, provided a sufficient number of individuals have opportunities to make proposals. In policy spaces with either pork barrel or pure redistributional politics (where a Condorcet winner does not exist), the last proposer is effectively a dictator or near-dictator under relatively weak conditions. [source] Medical association rule mining using genetic network programmingELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 2 2008Kaoru Shimada Abstract An efficient algorithm for building a classifier is proposed based on an important association rule mining using genetic network programming (GNP). The proposed method measures the significance of the association via the chi-squared test. Users can define the conditions of important association rules for building a classifier flexibly. The definition can include not only the minimum threshold chi-squared value, but also the number of attributes in the association rules. Therefore, all the extracted important rules can be used for classification directly. GNP is one of the evolutionary optimization techniques, which uses the directed graph structure as genes. Instead of generating a large number of candidate rules, our method can obtain a sufficient number of important association rules for classification. In addition, our method suits association rule mining from dense databases such as medical datasets, where many frequently occurring items are found in each tuple. In this paper, we describe an algorithm for classification using important association rules extracted by GNP with acquisition mechanisms and present some experimental results of medical datasets. © 2008 Wiley Periodicals, Inc. Electron Comm Jpn, 91(2): 46,54, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10022 [source] Identification of potentially toxic environmental Microcystis by individual and multiple PCR amplification of specific microcystin synthetase gene regionsENVIRONMENTAL TOXICOLOGY, Issue 3 2005Youness Ouahid Abstract Reliable cyanotoxin monitoring in water reservoirs is difficult because of, among other reasons, unpredictable changes in cyanobacteria biomass, toxin production, and inadequate sampling frequency. Therefore, it would be useful to identify potentially microcystin-producing strains of cyanobacterial populations in field samples. With this aim, we developed a methodology to distinguish microcystin-producing from non-producing Microcystis strains by amplifying six characteristic segments of the microcystin synthetase mcy cluster, three corresponding to the nonribosomal peptide synthetase, genes mcyA, mcyB, and mcyC, and three to the polyketide synthase, genes mcyD, mcyE, and mcyG. For this purpose five new primer sets were designed and tested using purified DNA, cultured cells, and field colonies as DNA sources. Simultaneous amplification of several genes in multipex PCR reactions was performed in this study. The results obtained showed that: (i) the expected specific amplicons were obtained with all microcystin-producing strains but not with nonproducing strains; (ii) cells could be directly used as DNA templates, 2000 cells being a sufficient number in most cases; (iii) simultaneous amplification of several gene regions is feasible both with cultured cells and with field colonies. Our data support the idea that the presence of various mcy genes in Microcystis could be used as a criterion for ascribing potential toxigenicity to field strains, and the possibility of applying whole-cell assays for the simultaneous amplification of various genes may contribute significantly to simplifying toxigenicity testing. © 2005 Wiley Periodicals, Inc. Environ Toxicol 20: 235,242, 2005. [source] Radiological interpretation of the navicular boneEQUINE VETERINARY EDUCATION, Issue 5 2008S. Dyson Summary Acquisition of a sufficient number of high quality radiographic views is an essential prerequisite to accurate radiological interpretation of the navicular bone. This requires appropriate preparation of the foot, careful attention to limb position and to both centring and direction of the x-ray beam, according to hoof capsule conformation. Artefacts are easily created. Potentially significant radiological abnormalities include: entheseiophytes at the proximomedial and proximolateral aspect of the bone; proximal or distal extension of the flexor border of the bone, distal border fragments, 8 or more large and variably shaped distal border radiolucent zones; discrete radiolucent areas in the spongiosa with or without detectable communication with the flexor cortex; new bone at the sagittal ridge; increased thickness of the flexor cortex; sclerosis of the spongiosa; and a bipartite bone. [source] Activation of class I metabotropic glutamate receptors limits dendritic growth of Purkinje cells in organotypic slice culturesEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2006Alexandra Sirzen-Zelenskaya Abstract The development of the dendritic tree of a neuron is a complex process which is thought to be regulated strongly by signals from afferent fibers. We showed previously that the blockade of glutamatergic excitatory neurotransmission has little effect on Purkinje cell dendritic development. We have now studied the effects of glutamate receptor agonists on the development of Purkinje cell dendrites in mouse organotypic slice cultures. The activation of N -methyl- d -aspartate receptors had no major effect on Purkinje cell dendrites and the activation of (RS)-alpha-amino-3-hydroxy-5-methyl-4-isoxazole proprionic acid receptors was strongly excitotoxic so that no analysis of its effects on dendritic development was possible. The activation of metabotropic glutamate receptors led to a very strong inhibition of dendritic growth, resulting in Purkinje cells with very small stubby dendrites. This effect was specific for the activation of class I metabotropic glutamate receptors and could not be reduced by blocking synaptic transmission in the cultures, indicating that it was mediated by receptors present on Purkinje cells. Pharmacological experiments suggest that the signaling pathway involved does not require activation of phospholipase C or protein kinase C. The inhibition of dendritic growth by activation of class I metabotropic glutamate receptor could be a useful negative feedback mechanism for limiting the size of the dendritic tree of Purkinje cells after the establishment of a sufficient number of parallel fiber contacts. This developmental mechanism could protect Purkinje cells from excitotoxic death through excessive release of glutamate from an overload of parallel fiber contacts. [source] Enhanced system design for download and streaming services using Raptor codes,,EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 2 2009Tiago Gasiba Raptor codes have been recently standardised by 3rd Generation Partnership Project (3GPP) to be used in the application layer (AL) for multimedia broadcast and multicast services (MBMS) including download delivery and streaming delivery. Furthermore, digital video broadcast (DVB) has also recommended the inclusion of these Raptor codes for IP-datacast services. In this paper, enhancements on the system and receiver design using Raptor codes are studied, namely the permeable layer receiver (PLR) and the individual post-repair mechanism. With the PLR, the partial information ignored in the conventional receiver is passed from lower layer to higher layer. We show how a practical and efficient implementation of the Raptor decoder as a PLR can be done, which can not only achieve huge performance gains, but the gains can be achieved at an affordable low decoding complexity. Whereas the PLR is employed for enhancing both download and streaming services, the post-repair aims at guaranteeing reliable download delivery when a feedback channel is available. We propose here two efficient post-repair algorithms which fully exploit the properties of the Raptor codes. One allows to find a minimum set of source symbols to be requested in the post-delivery, and another allows to find a sufficient number of consecutive repair symbols. Selected simulations verify the good performance of proposed techniques. Copyright © 2008 John Wiley & Sons, Ltd. [source] Ricci flows and infinite dimensional algebrasFORTSCHRITTE DER PHYSIK/PROGRESS OF PHYSICS, Issue 6-7 2004I. Bakas The renormalization group equations of two-dimensional sigma models describe geometric deformations of their target space when the world-sheet length changes scale from the ultra-violet to the infra-red. These equations, which are also known in the mathematics literature as Ricci flows, are analyzed for the particular case of two-dimensional target spaces, where they are found to admit a systematic description as Toda system. Their zero curvature formulation is made possible with the aid of a novel infinite dimensional Lie algebra, which has anti-symmetric Cartan kernel and exhibits exponential growth. The general solution is obtained in closed form using Bäcklund transformations, and special examples include the sausage model and the decay process of conical singularities to the plane. Thus, Ricci flows provide a non-linear generalization of the heat equation in two dimensions with the same dissipative properties. Various applications to dynamical problems of string theory are also briefly discussed. Finally, we outline generalizations to higher dimensional target spaces that exhibit sufficient number of Killing symmetries. [source] Artificial neural network inversion of magnetotelluric data in terms of three-dimensional earth macroparametersGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 1 2000Vjacheslav Spichak The possibility of solving the three-dimensional (3-D) inverse problem of geoelectrics using the artificial neural network (ANN) approach is investigated. The properties of a supervised ANN based on the back-propagation scheme with three layers of neurons are studied, and the ANN architecture is adjusted. A model class consisting of a dipping dyke in the basement of a two-layer earth with the dyke in contact with the overburden is used for numerical experiments. Six macroparameters of the 3-D model, namely the thickness of the top layer, which coincides with the depth of the dyke (D), the conductivity ratio between the first and second layers (C1,/C2,), the conductivity contrast of the dyke (C/C2,), and the width (W ), length (L ) and dip angle of the dyke (A), are used. Various groups of magnetotelluric field components and their transformations are studied in order to estimate the effect of the data type used on the ANN recognition ability. It is found that use of only the xy - and yx -components of impedance phases results in reasonable recognition errors for all unknown parameters (D: 0.02 per cent, C1/C2: 8.4 per cent, C/C2: 26.8 per cent, W : 0.02 per cent, L : 0.02 per cent, A: 0.24 per cent). The influence of the size and shape of the training data pool (including the ,gaps in education' and ,no target' effects) on the recognition properties is studied. Results from numerous ANN tests demonstrate that the ANN possesses good enough interpolation and extrapolation abilities if the training data pool contains a sufficient number of representative data sets. The effect of noise is estimated by means of mixing the synthetic data with 30, 50 and 100 per cent Gaussian noise. The unusual behaviour of the recognition errors for some of the model parameters when the data become more noisy (in particular, the fact that an increase in error is followed by a decrease) indicates that the use of standard techniques of noise reduction may give an opposite result, so the development of a special noise treatment methodology is required. Thus, it is shown that ANN-based recognition can be successfully used for inversion if the data correspond to the model class familiar to the ANN. No initial guess regarding the parameters of the 3-D target or 1-D layering is required. The ability of the ANN to teach itself using real geophysical (not only electromagnetic) data measured at a given location over a sufficiently long period means that there is the potential to use this approach for interpreting monitoring data. [source] The analysis of efficiency among a small number of organisations: How inferences can be improved by exploiting patient-level dataHEALTH ECONOMICS, Issue 6 2008Kim Rose Olsen Abstract Those responsible for monitoring and managing the performance of health-care organisations face the common problem that the relationship between observed performance and effort is difficult to establish. A solution is to compare the performance of multiple organisations, but this requires a sufficient number of comparators. Faced with a small sample, it may be possible to exploit other information sources. Multilevel regression models are applied to analyse the performance of six Danish vascular departments in 2004 using a patient-level data set. We find that treatment costs are higher for smokers, older patients, patients with cerebrovascular and pulmonal diseases and for those subject to acute hospitalisation and with longer lengths of stay. Costs are lower for patients who are having follow-up surgery and for patients who receive some form of home care, suggesting that there may be some substitution of care input between vascular departments and other care providers. We estimate the relative efficiency of each department. The construction of confidence intervals allows the six departments to be sorted into two groups containing the least and most efficient departments. Conclusions about relative efficiency are robust to model specification, choice of estimator and hold at the 95% confidence level. Copyright © 2007 John Wiley & Sons, Ltd. [source] The physician,patient relationship: the impact of patient-obtained medical informationHEALTH ECONOMICS, Issue 8 2006Bin Xie Abstract We investigate the impact of patient-obtained medical information (POMI) on the physician,patient relationship when patients, as a group, are heterogeneously informed and a physician's interests do not coincide with those of her patients. Introducing additional well-informed patients to the population discontinuously affects the physician's strategy, having no effect unless a sufficient quantity is added. When few patients are well informed, increasing the precision of their information level has no effect on the physician's strategy. Alternately, when a sufficient number of well-informed patients exists, increasing the precision of their information allows all patients to free-ride by receiving more appropriate treatment recommendations. Counterintuitively, we also identify circumstances under which increasing the general level of information may potentially harm patients. Copyright © 2006 John Wiley & Sons, Ltd. [source] Improving interpolation of daily precipitation for hydrologic modelling: spatial patterns of preferred interpolatorsHYDROLOGICAL PROCESSES, Issue 23 2009Daniel Kurtzman Abstract Detailed hydrologic models require high-resolution spatial and temporal data. This study aims at improving the spatial interpolation of daily precipitation for hydrologic models. Different parameterizations of (1) inverse distance weighted (IDW) interpolation and (2) A local weighted regression (LWR) method in which elevation is the explanatory variable and distance, elevation difference and aspect difference are weighting factors, were tested at a hilly setting in the eastern Mediterranean, using 16 years of daily data. The preferred IDW interpolation was better than the preferred LWR scheme in 27 out of 31 validation gauges (VGs) according to a criteria aimed at minimizing the absolute bias and the mean absolute error (MAE) of estimations. The choice of the IDW exponent was found to be more important than the choice of whether or not to use elevation as explanatory data in most cases. The rank of preferred interpolators in a specific VG was found to be a stable local characteristic if a sufficient number of rainy days are averaged. A spatial pattern of the preferred IDW exponents was revealed. Large exponents (3) were more effective closer to the coast line whereas small exponents (1) were more effective closer to the mountain crest. This spatial variability is consistent with previous studies that showed smaller correlation distances of daily precipitation closer to the Mediterranean coast than at the hills, attributed mainly to relatively warm sea-surface temperature resulting in more cellular convection coastward. These results suggest that spatially variable, physically based parameterization of the distance weighting function can improve the spatial interpolation of daily precipitation. Copyright © 2009 John Wiley & Sons, Ltd. [source] Detection and quantification of flaws in structures by the extended finite element method and genetic algorithmsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 3 2010Haim Waisman Abstract This paper investigates the extended finite element method (XFEM)-GA detection algorithm proposed by Rabinovich et al. (Int. J. Numer. Meth. Engng 2007; 71(9):1051,1080; Int. J. Numer. Meth. Engng 2009; 77(3):337,359) on elastostatic problems with different types of flaws. This algorithm is designed for non-destructive assessment of structural components. Trial flaws are modeled using the XFEM as the forward problem and genetic algorithms (GAs) are employed as the optimization method to converge to the true flaw location and size. The main advantage of the approach is that XFEM alleviates the need for re-meshing the domain at every new iteration of the inverse solution process and GAs have proven to be robust and efficient optimization techniques in particular for this type of problems. In this paper the XFEM-GA methodology is applied to elastostatic problems where flaws are considered as straight cracks, circular holes and non-regular-shaped holes. Measurements are obtained from strain sensors that are attached to the surface of the structure at specific locations and provide the target solution to the GA. The results show convergence robustness and accuracy provided that a sufficient number of sensors are employed and sufficiently large flaws are considered. Copyright © 2009 John Wiley & Sons, Ltd. [source] Simultaneous input and parameter estimation with input observers and set-membership parameter bounding: theory and an automotive applicationINTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 5 2006I. Kolmanovsky Abstract The paper addresses an on-line, simultaneous input and parameter estimation problem for a first-order system affected by measurement noise. This problem is motivated by practical applications in the area of engine control. Our approach combines an input observer for the unknown input with a set-membership algorithm to estimate the parameter. The set-membership algorithm takes advantage of a priori available information such as (i) known bounds on the unknown input, measurement noise and time rate of change of the unknown input; (ii) the form of the input observer in which the unknown parameter affects only the observer output; and (iii) the input observer error bounds for the case when the parameter is known exactly. The asymptotic properties of the algorithm as the observer gain increases are delineated. It is shown that for accurate estimation the unknown input needs to approach the known bounds a sufficient number of times (these time instants need not be known). Powertrain control applications are discussed and a simulation example based on application to engine control is reported. A generalization of the basic ideas to higher order systems is also elaborated. Copyright © 2006 John Wiley & Sons, Ltd. [source] Recombinant Human Parathyroid Hormone (1,34) [Teriparatide] Improves Both Cortical and Cancellous Bone StructureJOURNAL OF BONE AND MINERAL RESEARCH, Issue 11 2003Yebin Jiang MD Abstract Histomorphometry and ,CT of 51 paired iliac crest biopsy specimens from women treated with teriparatide revealed significant increases in cancellous bone volume, cancellous bone connectivity density, cancellous bone plate-like structure, and cortical thickness, and a reduction in marrow star volume. Introduction: We studied the ability of teriparatide (rDNA origin) injection [rhPTH(1,34), TPTD] to improve both cancellous and cortical bone in a subset of women enrolled in the Fracture Prevention Trial of postmenopausal women with osteoporosis after a mean treatment time of 19 months. This is the first report of a biopsy study after treatment with teriparatide having a sufficient number of paired biopsy samples to provide quantitative structural data. Methods: Fifty-one paired iliac crest bone biopsy specimens (placebo [n = 19], 20 ,g teriparatide [n = 18], and 40 ,g teriparatide [n = 14]) were analyzed using both two-dimensional (2D) histomorphometry and three-dimensional (3D) microcomputed tomography (,CT). Data for both teriparatide treatment groups were pooled for analysis. Results and Conclusions: By 2D histomorphometric analyses, teriparatide significantly increased cancellous bone volume (median percent change: teriparatide, 14%; placebo, ,24%; p = 0.001) and reduced marrow star volume (teriparatide, ,16%; placebo, 112%; p = 0.004). Teriparatide administration was not associated with osteomalacia or woven bone, and there were no significant changes in mineral appositional rate or wall thickness. By 3D cancellous and cortical bone structural analyses, teriparatide significantly decreased the cancellous structure model index (teriparatide, ,12%; placebo, 7%; p = 0.025), increased cancellous connectivity density (teriparatide, 19%; placebo, ,14%; p = 0.034), and increased cortical thickness (teriparatide, 22%; placebo, 3%; p = 0.012). These data show that teriparatide treatment of postmenopausal women with osteoporosis significantly increased cancellous bone volume and connectivity, improved trabecular morphology with a shift toward a more plate-like structure, and increased cortical bone thickness. These changes in cancellous and cortical bone morphology should improve biomechanical competence and are consistent with the substantially reduced incidences of vertebral and nonvertebral fractures during administration of teriparatide. [source] New Devices for Chronic Ventricular SupportJOURNAL OF CARDIAC SURGERY, Issue 3 2001F.A.C.S., F.C.C.P., Kenneth L. Franco M.D. Congestive heart failure affects 5 million people in the United States with 500,000 new cases diagnosed each year. Medical and surgical therapy have helped many patients but when these options fail, heart transplantation remains the only other treatment available to help improve their condition. Heart transplantation suffers from the lack of a sufficient number of suitable donor organs, the complications of chronic immunosuppression, and many patients die while on the waiting list. A number of pulsatile and nonpulsatile cardiac assist devices are being developed to provide chronic support for patients with heart failure and to be an alternative to heart transplantation. It is estimated that as many as 60,000 patients with heart failure could be helped by mechanical devices used for chronic support. For these devices to be effective they must provide sufficient cardiac output to allow patients to perform their daily activities, have a low risk of thromboemboli, be fully implantable thereby reducing the risk of infection, and have a low incidence of device malfunction requiring part or all of the device to be replaced. In this article, we will review several new devices which have been developed over the past 5 years or so and will be in human clinical trials in the United States soon, either as a bridge or as an alternative to heart transplantation. [source] Kinetic studies during peripheral blood stem cell collection show CD34+ cell recruitment intra-apheresisJOURNAL OF CLINICAL APHERESIS, Issue 3 2001Lene Meldgaard Knudsen Abstract A sufficient number of CD34+ cells in the peripheral blood stem cell product is important to achieve a rapid and sustained engraftment. The purpose of the present work was to study CD34+ cell kinetics during leukapheresis. Blood samples before and after leukapheresis were analysed for CD34+ cells in 205 procedures. The number of CD34+ cells after plus the number of CD34+ cells harvested was 1.5-fold greater than the number available at the beginning of the procedure, indicating recruitment of CD34+ cells during leukapheresis. In a subgroup of 66 procedures, granulocytes and platelets were measured. In contrast to CD34+ cells, these cell fractions were not recruited to the blood stream during leukapheresis. An additional nine patients were studied with serial blood measurements during leukapheresis, showing an initial decline that was followed by an increase in CD34+ cells during leukapheresis. In conclusion, CD34+ cells are recruited to the blood during the leukapheresis procedure in contrast to granulocytes and platelets. J. Clin. Apheresis. 16:114,119, 2001. © 2001 Wiley-Liss, Inc. [source] Reduced reproductive success and offspring survival in fragmented populations of the forest herb Phyteuma spicatumJOURNAL OF ECOLOGY, Issue 6 2005ANNETTE KOLB Summary 1Habitat fragmentation, which reduces the size and increases the isolation of populations, is a major threat to biodiversity. For Phyteuma spicatum, a self-incompatible, rare understorey herb in deciduous forests of north-western Germany, I tested the hypotheses that: (i) fitness (in terms of reproductive success) is reduced in small or isolated populations, (ii) reproduction in small populations is reduced by pollen limitation and (iii) genetic effects cause fitness reductions in small populations. 2I compared the reproductive success of plants of Phyteuma in 14 populations of different size and degree of isolation. Seed production was, as predicted, positively related to population size but was also influenced by plant size, although not by population isolation, density or habitat quality. 3I performed supplemental hand-pollinations in 10 of the 14 populations using pollen from the same population (test for pollen quantity) or from another large population (pollen quality). The proportional difference in seed production between hand-pollinated plants and open-pollinated controls increased with decreasing population size, indicating pollinator limitation of reproduction in small populations. There was no difference between the two hand-pollination treatments, suggesting that a sufficient number of cross-compatible mates was available even in the smallest populations. 4Progeny from the 14 populations were grown for 32 weeks in a common environment. There was no effect of population size on germination, but final seedling survival was positively related to population size, and this relationship was more pronounced in the glasshouse than under more favourable growing conditions in a common garden. Genetic effects may thus reduce fitness (here measured in terms of survival) in plants from small populations, making them more susceptible to environmental stress. 5The results suggest that both reproduction and offspring performance may be reduced in small populations even of long-lived species such as Phyteuma spicatum. Different processes, such as pollen limitation and genetic deterioration, may interact and affect local population dynamics and the persistence of species in fragmented landscapes. [source] Sales by multi-product retailersMANAGERIAL AND DECISION ECONOMICS, Issue 4 2006Timothy J. Richards This paper examines the rationale underlying periodic price promotions, or sales, for perishable food products by supermarket retailers. Whereas previous studies explain sales in a single-product context as arising from informational, storage cost, or demand heterogeneity, this study focuses on the central role of retailers as multi-product sellers of complementary goods. By offering a larger number of discounted products within a particular category, retailers are able to attract a sufficient number of customers to offset the effect of lower margins on sale items by selling more high-margin items. The implications that emerge from the resulting mixed-strategy equilibrium are tested in a product-level, retail-scanner data set of fresh fruit sales. Hypotheses regarding the rationale and effectiveness of sales are tested by estimating econometric models that describe (1) the number of sales items per store, (2) the depth of a given sale, and (3) promotion effectiveness on store-level demand. The results of this econometric analysis support the hypothesis that the breadth and depth of price promotions are complementary marketing tools, thus explaining how EDLP and HI-LO store formats can exist in the same monopolistically competitive market equilibrium. Copyright © 2006 John Wiley & Sons, Ltd. [source] Infrared multiple photon dissociation spectroscopy of ions in Penning trapsMASS SPECTROMETRY REVIEWS, Issue 3 2009John R. Eyler Abstract The ability of Paul and Penning traps to contain ions for time periods ranging from milliseconds to minutes allows the trapped ions to be subjected to laser irradiation for extended lengths of time. In this way, relatively low-powered tunable infrared lasers can be used to induce ion fragmentation when a sufficient number of infrared photons are absorbed, a process known as infrared multiple photon dissociation (IRMPD). If ion fragmentation is monitored as a function of laser wavelength, a photodissociation action spectrum can be obtained. The development of widely tunable infrared laser sources, in particular free electron lasers (FELs) and optical parametric oscillators/amplifiers (OPO/As), now allows spectra of trapped ions to be obtained for the entire "chemically relevant" infrared spectral region. This review describes experiments in which tunable infrared lasers have been used to irradiate ions in Penning traps. Early studies which utilized tunable carbon dioxide lasers with a limited output range are first reviewed. More recent studies with either FEL or OPO/A irradiation sources are then covered. The ionic systems examined have ranged from small hydrocarbons to multiply charged proteins, and they are discussed in approximate order of increasing complexity. © 2009 Wiley Periodicals, Inc., Mass Spec Rev 28:448,467, 2009 [source] Development of functional LH Receptors on pig cumulus,oocyte complexes cultured in vitro by a novel two-step culture systemMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 8 2009Radek Procházka We show in the present study that freshly isolated pig cumulus,oocyte complexes (COCs) display a limited response to LH, as assessed by the expression of hyaluronan synthase 2 (Has2) mRNA, activation of protein kinase A (PKA), production of hyaluronic acid (HA) and progesterone, cumulus cell expansion and resumption of meiosis. These data indicate that freshly isolated COCs do not possess a sufficient number of functional LH receptors (LHR). However, the expression of Lhr significantly increased during the culture of COCs in vitro in a medium supplemented with FSH. Assuming that the effect of FSH on LHR induction is mediated via cAMP signaling pathways, we developed a new culture system, in which the COCs were pre-cultured for 72 hr in a medium supplemented with dbcAMP. The pre-cultured COCs remained in the germinal vesicle stage, their cumulus investment underwent a dramatic increase in size and gap junctions between the cumulus cells were preserved. The stimulation of such COCs with either FSH or LH led to the resumption and completion of meiosis, activation of PKA, expression of Has2, synthesis of large amounts of HA and progesterone, and extensive expansion of cumulus cells. We conclude that the formation of functional LHR is stimulated in cumulus cells during the culture in vitro in a cAMP-dependent pathway. The dbcAMP-treated COCs thus represent a new model in which the resumption of meiosis and cumulus expansion can be induced exclusively by the action of recombinant LH. Mol. Reprod. Dev. 76: 751,761, 2009. © 2009 Wiley-Liss, Inc. [source] Development of self-incompatible Brassica napus: (III) B. napus genotype effects on S-allele expressionPLANT BREEDING, Issue 1 2003V. L. Ripley Abstract Use of self-incompatibility (SI) as a pollination control method for Brassica napus hybrid production requires the development of a sufficient number of S-alleles that are expressed consistently in a range of B. napus lines. Self-incompatibility (SI) alleles have been transferred from Brassica oleracea and Brassica rapa into B. napus var. oleifera. An understanding of expression of these alleles in B. napus is essential for their commercial use. Four SI B. napus doubled haploids containing the B. oleracea S-alleles S2, S5, S13 and S24 were crossed to three B. napus cultivars to measure the B. napus genetic background effect on S-allele expression. A line x tester analysis indicated that the largest source of variation in the expression rate of SI was the S-allele itself. The B. napus genotypes tested contained modifier gene(s), some that enhanced SI expression and others that inhibited SI expression. The B. napus Canadian cultivar ,Westar' generally had a negative effect on SI expression while the European cultivar ,Topas' had a positive effect on the B. oleracea S-allele expression. The B. oleracea S-allele S24 was very similar in expression to the B. rapa allele W1. The application of these results for the use of B. oleracea S-alleles for hybrid production in B. napus is discussed. [source] Prevalence of ROPS-equipped tractors on minority operated farms in the US,AMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 5 2009John R. Myers MS Abstract Background Tractor overturns kill an average of 100 farmers and farm workers per year. Roll-over protective structures (ROPS) are a proven intervention, but are not on a sufficient number of tractors in the US to reduce these deaths. Little has been reported on ROPS use by racial minority farm operators. Methods Data from the NIOSH OISPA survey were used to assess ROPS prevalence rates from a random sample of racial minority farm operators for the year 2003, and ROPS prevalence rates from a random sample of all US farms for the year 2004. Results ROPS prevalence rates on minority farming operations follow similar patterns to ROPS prevalence rates on all US farms. A low prevalence of ROPS on farms was associated with operators over the age of 65 years, farms with small acreages, and farms operated on a part-time basis. The race of the operator had little impact on ROPS prevalence rates. Conclusions Factors such as acreage, farm operator age, region of the US, and full- or part-time farming status influence ROPS prevalence rates on farms more than the race of the operator. Understanding how ROPS prevalence differs across these farm and farm operator characteristics has the potential to efficiently target areas for ROPS promotion programs across the US. Am. J. Ind. Med. 52:408,418, 2009. © 2009 Wiley-Liss, Inc. [source] A chromospheric dark-cored fibril in Ca II IR spectraASTRONOMISCHE NACHRICHTEN, Issue 6 2010C. Beck Abstract We investigate the thermodynamical and magnetic properties of a "dark-cored" fibril seen in the chromospheric Ca II IR line at 854.2 nm to determine the physical process behind its appearance. We analyse a time series of spectropolarimetric observations obtained in the Ca II IR line at 854.2 nm and the photospheric Fe I line at 630.25 nm. We simultaneously invert the spectra in both wavelength ranges with the SIR code to obtain the temperature and velocity stratification with height in the solar atmosphere and the magnetic field properties in the photosphere. The structure can be clearly traced in the line-of-sight (LOS) velocity and the temperature maps. It connects from a small pore with kG fields to a region with lower field strength. The flow velocity and the temperature indicate that the height of the structure increases with increasing distance from the inner footpoint. The Stokes V signal of 854.2 nm shows a Doppler-shifted polarization signal with the same displacement as in the intensity profile, indicating that the supersonic flow seen in the LOS velocity is located within magnetized plasma. We conclude that the chromospheric dark-cored fibril traces a siphon flow along magnetic field lines, driven by the gas pressure difference caused by the higher magnetic field strength at the inner footpoint. We suggest that fast flows guided by the magnetic field lead to the appearance of "dark-cored" fibrils in intensity images. Although the observations included the determination of the polarization signal in the chromospheric Ca II IR line, the signal could not be analysed quantitatively due to the low S/N. Chromospheric polarimetry will thus require telescopes of larger aperture able to collect a sufficient number of photons for a reliable determination of polarization in deep and only weakly polarized spectral lines (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Avoidable risk factors in perinatal deaths: A perinatal audit in South AustraliaAUSTRALIAN AND NEW ZEALAND JOURNAL OF OBSTETRICS AND GYNAECOLOGY, Issue 1 2008Titia E. DE LANGE Objectives: To analyse risk factors of perinatal death, with an emphasis on potentially avoidable risk factors, and differences in the frequency of suboptimal care factors between maternity units with different levels of care. Methods: Six hundred and eight pregnancies (2001,2005) in South Australia resulting in perinatal death were described and compared to 86 623 live birth pregnancies. Results: Two hundred and seventy cases (44.4%) were found to have one or more avoidable maternal risk factors, 31 cases (5.1%) had a risk factor relating access to care, while 68 cases (11.2%) were associated with deficiencies in professional care. One hundred and four women (17.1% of cases) presented too late for timely medical care: 85% of these did have a sufficient number of antenatal visits. The following independent maternal risk factors for perinatal death were found: assisted reproductive technology (adjusted odds ratio (AOR) 3.16), preterm labour (AOR 22.05), antepartum haemorrhage (APH) abruption (AOR 6.40), APH other/unknown cause (AOR 2.19), intrauterine growth restriction (AOR 3.94), cervical incompetence (AOR 8.89), threatened miscarriage (AOR 1.89), pre-existing hypertension (AOR 1.72), psychiatric disorder (AOR 1.85) and minimal antenatal care (AOR 2.89). The most commonly found professional care deficiency in cases was the failure to act on or recognise high-risk pregnancies/complications, found in 49 cases (8.1%). Conclusion: Further improvements in perinatal mortality may be achieved by greater emphasis on the importance of antenatal care and educating women to recognise signs and symptoms that require professional assessment. Education of maternity care providers may benefit from a further focus on how to recognise and/or manage high-risk pregnancies. [source] Direct and correlated responses to artificial selection on flight activity in the oriental fruit moth (Lepidoptera: Tortricidae)BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2010MARCO V. G. TORRIANI The ability of a sufficient number of individuals to disperse is crucial for long-term survival of populations. However, dispersal is often energetically costly, and thus is expected to trade-off against other life-history traits. In insect pest species, the occurrence of individuals with high flight activity challenges management practices. We performed artificial selection on flight activity and measured correlated responses to selection in the oriental fruit moth, Grapholita (= Cydia) molesta, a widely distributed and expanding lepidopteran pest of fruit crops. Both sexes rapidly responded to the imposed regime of divergent selection, indicating an adaptive potential of flight activity in this species. Upward-selected moths died sooner than downward-selected ones, providing evidence for a cost of flight activity to adult survival, reputedly associated with enhanced metabolic rates. Oppositely-selected females had similar total reproductive output, disproving a trade-off between dispersal and reproduction, although females with higher flight activity laid their eggs sooner. The ratio of body weight to forewing surface (forewing loading) did not significantly differ between selected lines. The present study contributes to the understanding of dispersal evolution, and also provides new insights into life-history theory as well as important baseline data for the improvement of pest management practices. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100, 879,889. [source] Effects of data incompleteness on the relative performance of parsimony and Bayesian approaches in a supermatrix phylogenetic reconstruction of Mustelidae and Procyonidae (Carnivora)CLADISTICS, Issue 2 2010Mieczyslaw Wolsan Missing data are commonly thought to impede a resolved or accurate reconstruction of phylogenetic relationships, and probabilistic analysis techniques are increasingly viewed as less vulnerable to the negative effects of data incompleteness than parsimony analyses. We test both assumptions empirically by conducting parsimony and Bayesian analyses on an approximately 1.5 × 106 -cell (27 965 characters × 52 species) mustelid,procyonid molecular supermatrix with 62.7% missing entries. Contrary to the first assumption, phylogenetic relationships inferred from our analyses are fully (Bayesian) or almost fully (parsimony) resolved topologically with mostly strong support and also largely in accord with prior molecular estimations of mustelid and procyonid phylogeny derived with parsimony, Bayesian, and other probabilistic analysis techniques from smaller but complete or nearly complete data sets. Contrary to the second assumption, we found no compelling evidence in support of a relationship between the inferior performance of parsimony and taxon incompleteness (i.e. the proportion of missing character data for a taxon), although we found evidence for a connection between the inferior performance of parsimony and character incompleteness (i.e. no overlap in character data between some taxa). The relatively good performance of our analyses may be related to the large number of sampled characters, so that most taxa (even highly incomplete ones) are represented by a sufficient number of characters allowing both approaches to resolve their relationships. © The Willi Hennig Society 2009. [source] Applying species-sensitivity distributions in ecological risk assessment: Assumptions of distribution type and sufficient numbers of species,ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2000Michael C. Newman Abstract Species-sensitivity distribution methods assemble single-species toxicity data to predict hazardous concentrations (HCps) affecting a certain percentage (p) of species in a community. The fit of the lognormal model and required number of individual species values were evaluated with 30 published data sets. The increasingly common assumption that a lognormal model best fits these data was not supported. Fifteen data sets failed a formal test of conformity to a lognormal distribution; other distributions often provided better fit to the data than the lognormal distribution. An alternate bootstrap method provided accurate estimates of HCp without the assumption of a specific distribution. Approximate sample sizes producing HC5 estimates with minimal variance ranged from 15 to 55, and had a median of 30 species-sensitivity values. These sample sizes are higher than those suggested in recent regulatory documents. A bootstrap method is recommended that predicts with 95% confidence the concentration affecting 5% or fewer species. [source] Efficient generation of human hepatocytes by the intrahepatic delivery of clonal human mesenchymal stem cells in fetal sheep,HEPATOLOGY, Issue 6 2007Jason Chamberlain Alternative methods to whole liver transplantation require a suitable cell that can be expanded to obtain sufficient numbers required for successful transplantation while maintaining the ability to differentiate into hepatocytes. Mesenchymal stem cells (MSCs) possess several advantageous characteristics for cell-based therapy and have been shown to be able to differentiate into hepatocytes. Thus, we investigated whether the intrahepatic delivery of human MSCs is a safe and effective method for generating human hepatocytes and whether the route of administration influences the levels of donor-derived hepatocytes and their pattern of distribution throughout the parenchyma of the recipient's liver. Human clonally derived MSCs were transplanted by an intraperitoneal (n = 6) or intrahepatic (n = 6) route into preimmune fetal sheep. The animals were analyzed 56,70 days after transplantation by immunohistochemistry, enzyme-linked immunosorbent assay, and flow cytometry. The intrahepatic injection of human MSCs was safe and resulted in more efficient generation of hepatocytes (12.5% ± 3.5% versus 2.6% ± 0.4%). The animals that received an intrahepatic injection exhibited a widespread distribution of hepatocytes throughout the liver parenchyma, whereas an intraperitoneal injection resulted in a preferential periportal distribution of human hepatocytes that produced higher amounts of albumin. Furthermore, hepatocytes were generated from MSCs without the need to first migrate/lodge to the bone marrow and give rise to hematopoietic cells. Conclusion: Our studies provide evidence that MSCs are a valuable source of cells for liver repair and regeneration and that, by the alteration of the site of injection, the generation of hepatocytes occurs in different hepatic zones, suggesting that a combined transplantation approach may be necessary to successfully repopulate the liver with these cells. (HEPATOLOGY 2007.) [source] Understanding volunteer motivation for participation in a community-based food cooperativeINTERNATIONAL JOURNAL OF NONPROFIT & VOLUNTARY SECTOR MARKETING, Issue 1 2003Sally Hibbert Those concerned with social exclusion have increasingly recognised the value of community-level activities as a basis for the development of disadvantaged communities. Much community development activity is collective and depends on members of the community volunteering to take on tasks and responsibilities associated with the collective action. The long-term success of these activities is contingent on recruitment of sufficient numbers of volunteers and maintaining their commitment. The purpose of this research was to gain insights into volunteers' motives for participating in a community retail initiative, with a view to understanding the dynamics of their relationship with the enterprise as time passes. A series of in-depth interviews provided evidence that motivations and factors influencing involvement change over time. Relatively vague ideas of the potential benefits of volunteering that motivated initial involvement were clarified as volunteers gained experience of participating in the enterprise. There was overt recognition of skill development and growth in self-esteem and confidence that had been gained during the first few months of working on the project and there was anticipation that these would be enhanced through ongoing involvement. The implications of these findings are discussed and some future research directions are proposed. Copyright © 2003 Henry Stewart Publications [source] | ||||||||||||||||||||||||||||