739 research outputs found
Closing yield gaps: how sustainable can we be?
Global food production needs to be increased by 60-110% between 2005 and 2050 to meet growing food and feed demand. Intensification and/or expansion of agriculture are the two main options available to meet the growing crop demands. Land conversion to expand cultivated land increases GHG emissions and impacts biodiversity and ecosystem services. Closing yield gaps to attain potential yields may be a viable option to increase the global crop production. Traditional methods of agricultural intensification often have negative externalities. Therefore, there is a need to explore location-specific methods of sustainable agricultural intensification. We identified regions where the achievement of potential crop calorie production on currently cultivated land will meet the present and future food demand based on scenario analyses considering population growth and changes in dietary habits. By closing yield gaps in the current irrigated and rain-fed cultivated land, about 24% and 80% more crop calories can respectively be produced compared to 2000. Most countries will reach food self-sufficiency or improve their current food self-sufficiency levels if potential crop production levels are achieved. As a novel approach, we defined specific input and agricultural management strategies required to achieve the potential production by overcoming biophysical and socioeconomic constraints causing yield gaps. The management strategies include: fertilizers, pesticides, advanced soil management, land improvement, management strategies coping with weather induced yield variability, and improving market accessibility. Finally, we estimated the required fertilizers (N, P2O5, and K2O) to attain the potential yields. Globally, N-fertilizer application needs to increase by 45-73%, P2O5-fertilizer by 22-46%, and K2O-fertilizer by 2-3 times compared to the year 2010 to attain potential crop production. The sustainability of such agricultural intensification largely depends on the way management strategies for closing yield gaps are chosen and implemented
Propositional Dynamic Logic with Converse and Repeat for Message-Passing Systems
The model checking problem for propositional dynamic logic (PDL) over message
sequence charts (MSCs) and communicating finite state machines (CFMs) asks,
given a channel bound , a PDL formula and a CFM ,
whether every existentially -bounded MSC accepted by
satisfies . Recently, it was shown that this problem is
PSPACE-complete.
In the present work, we consider CRPDL over MSCs which is PDL equipped with
the operators converse and repeat. The former enables one to walk back and
forth within an MSC using a single path expression whereas the latter allows to
express that a path expression can be repeated infinitely often. To solve the
model checking problem for this logic, we define message sequence chart
automata (MSCAs) which are multi-way alternating parity automata walking on
MSCs. By exploiting a new concept called concatenation states, we are able to
inductively construct, for every CRPDL formula , an MSCA precisely
accepting the set of models of . As a result, we obtain that the model
checking problem for CRPDL and CFMs is still in PSPACE
List of New Names of Plant Pathogenic Bacteria (2008-2010)
In 2010 the International Society of Plant Pathology Committee on the Taxonomy of Plant Pathogenic Bacteria published the Comprehensive List of Names of Plant Pathogenic Bacteria, 1980-2007 to provide an authoritative register of names of plant pathogens. In this manuscript we update the list of names by cataloguing names published from 2008 to 2010. We provide those names that have been validly and effectively published in this time frame, the proposed names that we judged to be invalid and names published earlier that did not make the previous lists. We also discuss problems that arise in the naming of strains that fall into the status Candidatus and nomenclatural problems in the genus Xanthomonas
List of New Names of Plant Pathogenic Bacteria (2011-2012)
The International Society of Plant Pathology Committee on the Taxonomy of Plant Pathogenic Bacteria has responsibility to evaluate the names of newly proposed pathovars for adherence to the International Standards for Naming Pathovars of Phytopathogenic Bacteria. Currently, the Comprehensive List of Names and the List of New Names of Plant Pathogenic Bacteria provide the authoritative register of names of bacterial plant pathogens. In this manuscript we up-date the list of names by cataloguing and evaluating names of plant pathogenic bacteria published in 2011 and 2012. We provide those names that have been validly and effectively published in this time frame, the proposed names that we judged to be invalid, and names published earlier that did not make the previous lists
from decays: contour-improved versus fixed-order summation in a new QCD perturbation expansion
We consider the determination of from hadronic decays, by
investigating the contour-improved (CI) and the fixed-order (FO)
renormalization group summations in the frame of a new perturbation expansion
of QCD, which incorporates in a systematic way the available information about
the divergent character of the series. The new expansion functions, which
replace the powers of the coupling, are defined by the analytic continuation in
the Borel complex plane, achieved through an optimal conformal mapping. Using a
physical model recently discussed by Beneke and Jamin, we show that the new
CIPT approaches the true results with great precision when the perturbative
order is increased, while the new FOPT gives a less accurate description in the
regions where the imaginary logarithms present in the expansion of the running
coupling are large. With the new expansions, the discrepancy of 0.024 in
between the standard CI and FO summations is reduced to
only 0.009. From the new CIPT we predict , which practically coincides with the result of the
standard FOPT, but has a more solid theoretical basis
Superconducting Transition Temperature in Heterogeneous Ferromagnet-Superconductor Systems
We study the shift of the the superconducting transition temperature in
ferromagnetic-superconducting bi-layers and in a superconducting film supplied
a square array of ferromagnetic dots. We find that the transition temperature
in these two cases change presumably in opposite direction and that its change
is not too small. We extend these results to multilayer structures. We predict
that rather small external magnetic field Oe can change the
transition temperature of the bilayer by 10% .Comment: 9 pages, 2 figure
New early Eocene tapiromorph perissodactyls from the Ghazij Formation of Pakistan, with implications for mammalian biochronology in Asia
Early Eocene mammals from Indo-Pakistan have only recently come under study. Here we describe the first tapiromorph perissodactyls from the subcontinent. Gandheralophus minor n. gen. and n. sp. and G. robustus n. sp. are two species of Isectolophidae differing in size and in reduction of the anterior dentition. Gandheralophus is probably derived from a primitive isectolophid such as Orientolophus hengdongensis from the earliest Eocene of China, and may be part of a South Asian lineage that also contains Karagalax from the middle Eocene of Pakistan. Two specimens are referred to a new, unnamed species of Lophialetidae. Finally, a highly diagnostic M3 and a molar fragment are described as the new eomoropid chalicothere Litolophus ghazijensis sp. nov. The perissodactyls described here, in contrast to most other mammalian groups published from the early Eocene of Indo-Pakistan, are most closely related to forms known from East and Central Asia. Tapiromorpha are diverse and biochronologically important in the Eocene there and our results allow the first biochronological correlation between early Eocene mammal faunas in Indo-Pakistan and the rest of Asia. We suggest that the upper Ghazij Formation of Pakistan is best correlated with the middle or late part of the Bumbanian Asian Land-Mammal Age, while the Kuldana and Subathu Formations of Pakistan and India are best correlated with the Arshantan Asian Land-Mammal Age
Superdeformed bands in 189Tl
Two superdeformed bands of 10 transitions each have been found in 189Tl extending the mass 190 region of
superdeformation down to neutron number N5108. The new bands can be interpreted as signature partners
and are proposed to be based on a proton i13/2 (V55/2) configuration, in analogy with the yrast superdeformed
band structures in the heavier odd-mass Tl isotopes. The dynamic moments of inertia of all these bands show
no noticeable differences as function of N, consistent with an essentially constant quadrupole deformation
from the center of the island to its edges
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