10,081 research outputs found
Tracking nitrogen losses in a greenhouse crop rotation experiment in North China using the EU-Rotate_N simulation model
Vegetable production in China is associated with high inputs of nitrogen, posing a risk of losses to the
environment. Organic matter mineralisation is a considerable source of nitrogen (N) which is hard to
quantify. In a two-year greenhouse cucumber experiment with different N treatments in North China,
non-observed pathways of the N cycle were estimated using the EU-Rotate_N simulation model.
EU-Rotate_N was calibrated against crop dry matter and soil moisture data to predict crop N uptake, soil
mineral N contents, N mineralisation and N loss. Crop N uptake (Modelling Efficiencies (ME) between
0.80 and 0.92) and soil mineral N contents in different soil layers (ME between 0.24 and 0.74) were
satisfactorily simulated by the model for all N treatments except for the traditional N management. The
model predicted high N mineralisation rates and N leaching losses, suggesting that previously published
estimates of N leaching for these production systems strongly underestimated the mineralisation of N
from organic matter
A Macroeconometric Model of the Chinese Economy
This paper describes a quarterly macroeconometric model of the Chinese economy. The model comprises household consumption, investment, government, trade, production, prices, money, and employment blocks. The equilibrium-correction form is used for all the behavioral equations and the general→simple dynamic specification approach is adopted. Great efforts have been made to achieve the best possible blend of standard long-run theories, country-specific institutional features and short-run dynamics in data. The tracking performance of the model is evaluated. Forecasting and empirical investigation of a number of topical macroeconomic issues utilizing model simulations have shown the model to be immensely useful.Macroeconometric model, Chinese economy, Forecasts, Simulations
Meiotic wave adds extra asymmetry to the development of female chicken gonads
Development of female gonads in the chicken is asymmetric. This asymmetry affects gene expression, morphology, and germ cell development; consequently only the left ovary develops into a functional organ, whereas the right ovary remains vestigial. In males, on the other hand, both gonads develop into functional testes. Here, we revisited the development of asymmetric traits in female (and male) chicken gonads between Hamburger Hamilton stage 16 (HH16) and hatching. At HH16, primordial germ cells migrated preferentially to the left gonad, accumulating in the left coelomic hinge between the gut mesentery and developing gonad in both males and females. Using the meiotic markers SYCP3 and phosphorylated H2AFX, we identified a previously undescribed, pronounced asymmetryc meiotic progression in the germ cells located in the central, lateral, and extreme cortical regions of the left female gonad from HH38 until hatching. Moreover, we observed that-in contrast to the current view-medullary germ cells are not apoptotic, but remain arrested in pre-leptotene until hatching. In addition to the systematic analysis of the asymmetric distribution of germ cells in female chicken gonads, we propose an updated model suggesting that the localization of germ cells-in the left or right gonad; in the cortex or medulla of the left gonad; and in the central part or the extremities of the left cortex-has direct consequences for their development and participation in adult reproduction
An approximation algorithm for the solution of the nonlinear Lane-Emden type equations arising in astrophysics using Hermite functions collocation method
In this paper we propose a collocation method for solving some well-known
classes of Lane-Emden type equations which are nonlinear ordinary differential
equations on the semi-infinite domain. They are categorized as singular initial
value problems. The proposed approach is based on a Hermite function
collocation (HFC) method. To illustrate the reliability of the method, some
special cases of the equations are solved as test examples. The new method
reduces the solution of a problem to the solution of a system of algebraic
equations. Hermite functions have prefect properties that make them useful to
achieve this goal. We compare the present work with some well-known results and
show that the new method is efficient and applicable.Comment: 34 pages, 13 figures, Published in "Computer Physics Communications
Photonic Localization of Interface Modes at the Boundary between Metal and Fibonacci Quasi-Periodic Structure
We investigated on the interface modes in a heterostructure consisting of a
semi-infinite metallic layer and a semi-infinite Fibonacci quasi-periodic
structure. Various properties of the interface modes, such as their spatial
localizations, self-similarities, and multifractal properties are studied. The
interface modes decay exponentially in different ways and the modes in the
lower stable gap possess highest spatial localization. A localization index is
introduced to understand the localization properties of the interface modes. We
found that the localization index of the interface modes in the upper stable
gap will converge to two slightly different constants according to the parity
of the Fibonacci generation. In addition, the localization-delocalization
transition is also found in the interface modes of the transient gap.Comment: 20 pages, 5figure
Use of thyroid hormones in hypothyroid and euthyroid patients: a 2022 THESIS questionnaire survey of members of the Latin American Thyroid Society (LATS)
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