1,761 research outputs found
Can China continue feeding itself ? the impact of climate change on agriculture
Several studies addressing the supply and demand for food in China suggest that the nation can largely meet its needs in the coming decades. However, these studies do not consider the effects of climate change. This paper examines whether near future expected changes in climate are likely to alter this picture. The authors analyze the effect of temperature and precipitation on net crop revenues using a cross section consisting of both rainfed and irrigated farms. Based on survey data from 8,405 households across 28 provinces, the results of the Ricardian analysis demonstrate that global warming is likely to be harmful to China but the impacts are likely to be very different in each region. The mid latitude region of China may benefit from warming but the southern and northern regions are likely to be damaged by warming. More precipitation is beneficial to Chinese farmers except in the wet southeast. Irrigated and rainfed farmers have similar responses to precipitation but not to temperature. Warmer temperatures may benefit irrigated farms but they are likely to harm rainfed farms. Finally, seasonal effects vary and are offsetting. Although we were able to measure the direct effect of precipitation and temperature, we could not capture the effects of change in water flow which will be very important in China. Can China continue feeding itself if climate changes? Based on the empirical results, the likely gains realized by some farmers will nearly offset the losses that will occur to other farmers in China. If future climate scenarios lead to significant reductions in water, there may be large damages not addressed in this study.Climate Change,Crops&Crop Management Systems,Global Environment Facility,Common Property Resource Development,Rural Development Knowledge&Information Systems
Community Battery Energy Storage Systems for Enhancing Distribution System Operation: A Multi-objective Optimization Approach
The growing penetration of distributed energy resources (DERs) in
distribution networks (DNs) raises new operational challenges, particularly in
terms of reliability and voltage regulation. In response to these challenges,
we introduce an innovative DN operation framework with multi-objective
optimization, leveraging community battery energy storage systems (C-BESS). The
proposed framework targets two key operational objectives: first, to minimize
voltage deviation, which is a concern for a distribution network service
provider (DNSP), and second, to maximize the utilization of DERs on the demand
side. Recognizing the conflicting nature of these objectives, we utilize C-BESS
to enhance the system's adaptability to dynamically adjust DN operations. The
multi-objective optimization problem is solved using the non-dominated sorting
genetic algorithm-II (NSGA-II). Case studies using real-world data are
conducted to validate the effectiveness of the proposed framework. The results
show significant improvements in voltage regulation and DER utilization,
demonstrating the potential of C-BESS in enabling more reliable DN operation.
Our findings contribute to the ongoing discourse on the role of C-BESS in DN
operation enhancement and DER integration.Comment: IEEE International Conference on Energy Technologies for Future
Grids, 2023 (IEEE ETFG 2023
Network-Aware Electric Vehicle Coordination for Vehicle-to-Anything Value Stacking Considering Uncertainties
The increased adoption of electric vehicles (EVs) has led to the development
of vehicle-to-anything (V2X) technologies, including vehicle-to-home (V2H),
vehicle-to-grid (V2G), and energy trading of EVs in the local grid. The EV
coordination can provide value to the grid and generate benefits for EVs.
However, network constraints and uncertainties in renewable energy and demand
pose significant challenges to EV coordination and restrict the realization of
these benefits. This paper develops a rolling-horizon optimization problem for
V2X value stacking to fully unlock the value of EV coordination, considering
power network constraints (such as voltage limits) and uncertainties in the
energy system. By coordinating EVs to perform V2H, V2G, and energy trading, our
approach exploits the most valuable services in real-time. We also analyze the
expected extra costs caused by the prediction errors to evaluate the impact of
uncertainties on V2X value stacking. We validate our value-stacking model using
real data from Australia's National Electricity Market (NEM), ISO New England
(ISO-NE), and New York ISO (NY-ISO) in the US. The results show that V2X value
stacking achieves significant benefits to EVs through energy cost reduction.
The uncertainty in the load has a higher impact on the value-stacking
performance than PV generation, indicating the importance of load prediction.Comment: The 59th annual IEEE Industrial and Commercial Power System Technical
Conference (I&CPS 2023
Spin-Injection Spectroscopy of a Spin-Orbit Coupled Fermi Gas
The coupling of the spin of electrons to their motional state lies at the
heart of recently discovered topological phases of matter. Here we create and
detect spin-orbit coupling in an atomic Fermi gas, a highly controllable form
of quantum degenerate matter. We reveal the spin-orbit gap via spin-injection
spectroscopy, which characterizes the energy-momentum dispersion and spin
composition of the quantum states. For energies within the spin-orbit gap, the
system acts as a spin diode. To fully inhibit transport, we open an additional
spin gap, thereby creating a spin-orbit coupled lattice whose spinful band
structure we probe. In the presence of s-wave interactions, such systems should
display induced p-wave pairing, topological superfluidity, and Majorana edge
states
Tentative detection of the gravitational magnification of type Ia supernovae
The flux from distant type Ia supernovae (SN) is likely to be amplified or
de-amplified by gravitational lensing due to matter distributions along the
line-of-sight. A gravitationally lensed SN would appear brighter or fainter
than the average SN at a particular redshift. We estimate the magnification of
26 SNe in the GOODS fields and search for a correlation with the residual
magnitudes of the SNe. The residual magnitude, i.e. the difference between
observed and average magnitude predicted by the "concordance model" of the
Universe, indicates the deviation in flux from the average SN. The linear
correlation coefficient for this sample is r=0.29. For a similar, but
uncorrelated sample, the probability of obtaining a correlation coefficient
equal to or higher than this value is ~10%, i.e. a tentative detection of
lensing at ~90% confidence level. Although the evidence for a correlation is
weak, our result is in accordance with what could be expected given the small
size of the sample.Comment: 7 pages, 2 figure
Mitochondrial Glycerol Phosphate Acyltransferase Directs the Incorporation of Exogenous Fatty Acids into Triacylglycerol
The mitochondrial isoform of glycerol-3-phosphate acyltransferase (GPAT), the first step in glycerolipid synthesis, is up-regulated by insulin and by high carbohydrate feeding via SREBP-1c, suggesting that it plays a role in triacylglycerol synthesis. To test this hypothesis, we overexpressed mitochondrial GPAT in Chinese hamster ovary (CHO) cells. When GPAT was overexpressed 3.8-fold, triacylglycerol mass was 2.7-fold higher than in control cells. After incubation with trace [14C]oleate (∼3 μM), control cells incorporated 4.7-fold more label into phospholipid than triacylglycerol, but GPAT-overexpressing cells incorporated equal amounts of label into phospholipid and triacylglycerol. In GPAT-overexpressing cells, the incorporation of label into phospholipid, particularly phosphatidylcholine, decreased 30%, despite normal growth rate and phospholipid content, suggesting that exogenous oleate was directed primarily toward triacylglycerol synthesis. Transiently transfected HEK293 cells that expressed a 4.4-fold increase in GPAT activity incorporated 9.7-fold more [14C]oleate into triacylglycerol compared with control cells, showing that the effect of GPAT overexpression was similar in two different cell types that had been transfected by different methods. When the stable, GPAT-overexpressing CHO cells were incubated with 100 μM oleate to stimulate triacylglycerol synthesis, they incorporated 1.9-fold more fatty acid into triacylglycerol than did the control cells. Confocal microscopy of CHO and HEK293 cells transfected with the GPAT-FLAG construct showed that GPAT was located correctly in mitochondria and was not present elsewhere in the cell. These studies indicate that overexpressed mitochondrial GPAT directs incorporation of exogenous fatty acid into triacylglycerol rather than phospholipid and imply that (a) mitochondrial GPAT and lysophosphatidic acid acyltransferase produce a separate pool of lysophosphatidic acid and phosphatidic acid that must be transported to the endoplasmic reticulum where the terminal enzymes of triacylglycerol synthesis are located, and (b) this pool remains relatively separate from the pool of lysophosphatidic acid and phosphatidic acid that contributes to the synthesis of the major phospholipid species.Instituto de Investigaciones BioquÃmicas de La Plat
Mitochondrial Glycerol Phosphate Acyltransferase Directs the Incorporation of Exogenous Fatty Acids into Triacylglycerol
The mitochondrial isoform of glycerol-3-phosphate acyltransferase (GPAT), the first step in glycerolipid synthesis, is up-regulated by insulin and by high carbohydrate feeding via SREBP-1c, suggesting that it plays a role in triacylglycerol synthesis. To test this hypothesis, we overexpressed mitochondrial GPAT in Chinese hamster ovary (CHO) cells. When GPAT was overexpressed 3.8-fold, triacylglycerol mass was 2.7-fold higher than in control cells. After incubation with trace [14C]oleate (∼3 μM), control cells incorporated 4.7-fold more label into phospholipid than triacylglycerol, but GPAT-overexpressing cells incorporated equal amounts of label into phospholipid and triacylglycerol. In GPAT-overexpressing cells, the incorporation of label into phospholipid, particularly phosphatidylcholine, decreased 30%, despite normal growth rate and phospholipid content, suggesting that exogenous oleate was directed primarily toward triacylglycerol synthesis. Transiently transfected HEK293 cells that expressed a 4.4-fold increase in GPAT activity incorporated 9.7-fold more [14C]oleate into triacylglycerol compared with control cells, showing that the effect of GPAT overexpression was similar in two different cell types that had been transfected by different methods. When the stable, GPAT-overexpressing CHO cells were incubated with 100 μM oleate to stimulate triacylglycerol synthesis, they incorporated 1.9-fold more fatty acid into triacylglycerol than did the control cells. Confocal microscopy of CHO and HEK293 cells transfected with the GPAT-FLAG construct showed that GPAT was located correctly in mitochondria and was not present elsewhere in the cell. These studies indicate that overexpressed mitochondrial GPAT directs incorporation of exogenous fatty acid into triacylglycerol rather than phospholipid and imply that (a) mitochondrial GPAT and lysophosphatidic acid acyltransferase produce a separate pool of lysophosphatidic acid and phosphatidic acid that must be transported to the endoplasmic reticulum where the terminal enzymes of triacylglycerol synthesis are located, and (b) this pool remains relatively separate from the pool of lysophosphatidic acid and phosphatidic acid that contributes to the synthesis of the major phospholipid species.Instituto de Investigaciones BioquÃmicas de La Plat
ARO-Net: Learning Implicit Fields from Anchored Radial Observations
We introduce anchored radial observations (ARO), a novel shape encoding for
learning implicit field representation of 3D shapes that is category-agnostic
and generalizable amid significant shape variations. The main idea behind our
work is to reason about shapes through partial observations from a set of
viewpoints, called anchors. We develop a general and unified shape
representation by employing a fixed set of anchors, via Fibonacci sampling, and
designing a coordinate-based deep neural network to predict the occupancy value
of a query point in space. Differently from prior neural implicit models that
use global shape feature, our shape encoder operates on contextual,
query-specific features. To predict point occupancy, locally observed shape
information from the perspective of the anchors surrounding the input query
point are encoded and aggregated through an attention module, before implicit
decoding is performed. We demonstrate the quality and generality of our
network, coined ARO-Net, on surface reconstruction from sparse point clouds,
with tests on novel and unseen object categories, "one-shape" training, and
comparisons to state-of-the-art neural and classical methods for reconstruction
and tessellation.Comment: Accepted by CVPR 2023. Code: https://github.com/yizhiwang96/ARO-Ne
RNA interference of gonadotropin-inhibitory hormone gene induces arousal in songbirds.
Gonadotropin-inhibitory hormone (GnIH) was originally identified in quail as a hypothalamic neuropeptide inhibitor of pituitary gonadotropin synthesis and release. However, GnIH neuronal fibers do not only terminate in the median eminence to control anterior pituitary function but also extend widely in the brain, suggesting it has multiple roles in the regulation of behavior. To identify the role of GnIH neurons in the regulation of behavior, we investigated the effect of RNA interference (RNAi) of the GnIH gene on the behavior of white-crowned sparrows, a highly social songbird species. Administration of small interfering RNA against GnIH precursor mRNA into the third ventricle of male and female birds reduced resting time, spontaneous production of complex vocalizations, and stimulated brief agonistic vocalizations. GnIH RNAi further enhanced song production of short duration in male birds when they were challenged by playbacks of novel male songs. These behaviors resembled those of breeding birds during territorial defense. The overall results suggest that GnIH gene silencing induces arousal. In addition, the activities of male and female birds were negatively correlated with GnIH mRNA expression in the paraventricular nucleus. Density of GnIH neuronal fibers in the ventral tegmental area was decreased by GnIH RNAi treatment in female birds, and the number of gonadotropin-releasing hormone neurons that received close appositions of GnIH neuronal fiber terminals was negatively correlated with the activity of male birds. In summary, GnIH may decrease arousal level resulting in the inhibition of specific motivated behavior such as in reproductive contexts
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