Impact of tree root pruning on yield of durum wheat and barley in a mediterranean alley cropping system

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Stock assessment of Lates niloticus (L.), Oreochromis niloticus (L.) and Rastrineobola argentea (Pellegrin) using fishery dependent data from the Tanzanian waters of Lake Victoria

Catch data were collected from three beaches in the Mwanza area of lake Victoria, Tanzania for Oreochromis niloticus (L.), Rastrineobola argentea (Pellegrin) and Lates niloticus (L.). Sampling took place in October 1997 and February, June and September 1998. The CPUE for O. niloticus was 3.9 to 6kg boat super(-1) and for R. argentea from 98 to 282 kg boat super(-1). There was no obvious trend in catch rates for L. niloticus. The modal length for O. niloticus recorded at Chole beach was 34cm TL. In February, fish were larger (41-45 cm) than in the other surveys. Rastrineobola argentea caught in October 1997 had modal length at 65 mm TL with some smaller fish. In February and June prominent length modes occurred at 45 and 58 mm respectively, which may represent the same cohort as the small fish caught in October 1997. In September 1998, there were two length modes at 46 and 60 mm. The 60 mm fish may represent the same cohort seen in previous surveys, suggesting growth from approximately 30 mm to 60 mm in an eleven-month period. Lates niloticus landed at Kayenze beach over the four surveys had a modal length of 46 cm TL. Fish species encountered on the three beaches during the surveys were O. niloticus, R. argentea, Bagrus docmak Forsskall, Clarias gariepinus (Burchell), Protopterus aethiopicus Heckel, Labeo victorians Boulenger, Synodontis afrofischeri Hilgendorf, Synodontis victoriae Boulanger, Schilbe intermedius (L.), Brycinus jacksonii (Boulanger), Mormyrus kannume Forsskall and Haplochromine cichlid

Arrow of time in a recollapsing quantum universe

We show that the Wheeler-DeWitt equation with a consistent boundary condition is only compatible with an arrow of time that formally reverses in a recollapsing universe. Consistency of these opposite arrows is facilitated by quantum effects in the region of the classical turning point. Since gravitational time dilation diverges at horizons, collapsing matter must then start re-expanding ``anticausally" (controlled by the reversed arrow) before horizons or singularities can form. We also discuss the meaning of the time-asymmetric expression used in the definition of ``consistent histories". We finally emphasize that there is no mass inflation nor any information loss paradox in this scenario.Comment: Many conceptual clarifications include

Telomeric NAP1L4 and OSBPL5 of the KCNQ1 cluster, and the DECORIN gene are not imprinted in human trophoblast stem cells

Background: Genomic imprinting of the largest known cluster, the Kcnq1/KCNQ1 domain on mChr7/hChr11, displays significant differences between mouse and man. Of the fourteen transcripts in this cluster, imprinting of six is ubiquitous in mice and humans, however, imprinted expression of the other eight transcripts is only found in the mouse placenta. The human orthologues of the latter eight transcripts are biallelically expressed, at least from the first trimester onwards. However, as early development is less divergent between species, placental specific imprinting may be present in very early gestation in both mice and humans. Methodology/Principal Findings: Human embryonic stem (hES) cells can be differentiated to embryoid bodies and then to trophoblast stem (EB-TS) cells. Using EB-TS cells as a model of post-implantation invading cytotrophoblast, we analysed allelic expression of two telomeric transcripts whose imprinting is placental specific in the mouse, as well as the ncRNA KCNQ1OT1, whose imprinted expression is ubiquitous in early human and mouse development. KCNQ1OT1 expression was monoallelic in all samples but OSBPL5 and NAP1L4 expression was biallelic in EB-TS cells, as well as undifferentiated hES cells and first trimester human fetal placenta. DCN on hChr12, another gene imprinted in the mouse placenta only, was also biallelically expressed in EB-TS cells. The germline maternal methylation imprint at the KvDMR was maintained in both undifferentiated hES cells and EB-TS cells. Conclusions/Significance: The question of placental specific imprinting in the human has not been answered fully. Using a model of human trophoblast very early in gestation we show a lack of imprinting of two telomeric genes in the KCNQ1 region and of DCN, whose imprinted expression is placental specific in mice, providing further evidence to suggest that humans do not exhibit placental specific imprinting. The maintenance of both differential methylation of the KvDMR and monoallelic expression of KCNQ1OT1 indicates that the region is appropriately regulated epigenetically in vitro. Human gestational load is less than in the mouse, resulting in reduced need for maternal resource competition, and therefore maybe also a lack of placental specific imprinting. If genomic imprinting exists to control fetal acquisition of maternal resources driven by the placenta, placenta-specific imprinting may be less important in the human than the mouse

Neural correlates of processing valence and arousal in affective words

Psychological frameworks conceptualize emotion along 2 dimensions, "valence" and "arousal." Arousal invokes a single axis of intensity increasing from neutral to maximally arousing. Valence can be described variously as a bipolar continuum, as independent positive and negative dimensions, or as hedonic value (distance from neutral). In this study, we used functional magnetic resonance imaging to characterize neural activity correlating with arousal and with distinct models of valence during presentation of affective word stimuli. Our results extend observations in the chemosensory domain suggesting a double dissociation in which subregions of orbitofrontal cortex process valence, whereas amygdala preferentially processes arousal. In addition, our data support the physiological validity of descriptions of valence along independent axes or as absolute distance from neutral but fail to support the validity of descriptions of valence along a bipolar continuum

MARKETING FINANCIAL PRODUCTS WITHIN THE ACTIVITY OF INVESTMENT BANKS

A production system which produces a large number of items in many steps can be modelled as a continuous flow problem. The resulting hyperbolic partial differential equation (PDE) typically is nonlinear and nonlocal, modeling a factory whose cycle time depends nonlinearly on the work in progress. One of the few ways to influence the output of such a factory is by adjusting the start rate in a time dependent manner.We study two prototypical control problems for this case: i) demand tracking where we determine the start rate that generates an output rate which optimally tracks a given time dependent demand rate and ii) backlog tracking which optimally tracks the cumulative demand. The method is based on the formal adjoint method for constrained optimization, incorporating the hyperbolic PDE as a constraint of a nonlinear optimization problem. We show numerical results on optimal start rate profiles for steps in the demand rate and for periodically varying demand rates and discuss the influence of the nonlinearity of the cycle time on the limits of the reactivity of the production system. Differences between perishable and non-perishable demand (demand vs. backlog tracking) are highlighted

On the Lipschitz continuity of spectral bands of Harper-like and magnetic Schroedinger operators

We show for a large class of discrete Harper-like and continuous magnetic Schrodinger operators that their band edges are Lipschitz continuous with respect to the intensity of the external constant magnetic field. We generalize a result obtained by J. Bellissard in 1994, and give examples in favor of a recent conjecture of G. Nenciu.Comment: 15 pages, accepted for publication in Annales Henri Poincar

Implications of Climate Science for Policy

Climate change presents the greatest challenge ever faced by our domestic and international institutions, and a great deal of the difficulty lies in the science of the issue. Because human influence on global climate differs in important ways from other environmental threats these peculiarities set the context for discussion of what can be done to reduce greenhouse gas emissions and to adapt to change that cannot be avoided. Following a brief summary of current understanding of how Earth’s climate works, five ways are presented by which the science of climate impinges on attempts to construct a policy response