269 research outputs found

    Study on the oasification process and its effects on soil particle distribution in the south rim of the Tarim Basin, China in recent 30 years

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    AbstractOasification is an important geography process in arid areas, although little research attention has been paid to the process compared to desertification. In fact, studying oasification not only directly reveals its effects on the environment, but can also uncover causes of desertification through examination of oasification causes and processes. In this study, oases located on the south rim of Tarim Basin in Xinjiang, China, were selected as a regional study area. For assessing changes in oases area over the past 30years, four images taken in September in 1977, 1992, 2000 and 2010 were used. To further investigate the effects of oasification on the environment, the Cele Oasis was specifically selected as a representative study area, and soil particle-size distributions (PSD) were analyzed. The results indicated that the oasification process was unmistakable and should receive more attention in the southern marginal zone of the Tarim Basin. In addition, the results also revealed that oasification can have positive effects on the soil environment. In terms of management implications, it is essential that farmland remain in continuous use after reclamation; otherwise, reclamation will weaken oasification and intensify desertification

    Computation on the Optimal Control of Networked Control Systems with Multiple Switching Modes Over High Speed Local Area Networks

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    The optimal control problem for the networked control system with multiple switching modes over high speed local area networks is addressed, where an initial state is a parametric vector. Because in the general case, the time delay is much less than the sampling period and the possibility of the packets collision is much lower, it can be assumed that the influence of the time delay and the packets loss on the optimal controller design can be ignored. On the basis of the assumption, the networked control systems with multiple switching modes are modeled as a hybrid system. Moreover, based on the Bellman type inequality for the hybrid systems, a dynamic program to solve the optimal control with a parameter vector is proposed, in every step of the technique, the feasible region is divided into evenly distributed grid points, and then, the optimal control law is transformed into maximizing the lower bound of the cost to go function in grid points. Finally, an experiment setup of the networked control system with multiple switching modes is constructed and a simulation example is given to illustrate the optimal control computation results

    Stoichiometry of C:N:P in the Roots of Alhagi sparsifolia Is More Sensitive to Soil Nutrients Than Aboveground Organs

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    The stoichiometry of carbon, nitrogen, and phosphorus (C:N:P) among leaves, stems, and roots reflects trade-offs in plants for acquiring resources and their growth strategy. The widely distributed plant Alhagi sparsifolia is an ideal species to study the ecological stoichiometry in different organs in response to the availability of nutrients and water in the desert ecosystem. However, which response of organs is most sensitive to environmental conditions is still unclear. To answer this question, we collected samples of plants and soils including not only aboveground leaves and stems, but also underground roots and soils from a wide range of arid areas during the growing season. The C, N, P, C:N, C:P, and N:P ratios in leaves, thorns, stems, and roots were derived to explore their relationship as well as their response mechanisms to nutrients and water spanning 1 m deep in the soil. The results showed that the order of N concentration was leaves > thorns > stems > roots, that the concentration of P in the leaves, thorns, and stems was similar, and that their values were higher than those in the roots. First, the C:N ratios in the leaves and stems were significantly positively correlated with the ratio in roots. The C:N ratios in each organ showed a significant relationship with the soil alkali hydrolyzable nitrogen (SAN) above a depth of 60 cm. In addition to SAN, soil available phosphorus (SAP) and soil organic carbon (SOC) affect the C:N ratio in the roots. Second, the C:P and N:P ratios in aboveground organs showed no correlations with the ratios in roots. The C:P and N:P ratios in the leaves and thorns have no relationship with soil nutrients, while the C:P ratio in roots was influenced by SAN and SOC in all soil layers. Finally, the N:P ratios in roots were also affected by nutrients in different soil depths at 0–20 and 60–80 cm. These results illustrate that the roots were more sensitive to soil nutrients than the aboveground parts. Our study of ecological stoichiometry also suggests a novel systematic approach for analyzing the sensitivity of responses of an organ to environmental conditions.Fil: Yin, Hui. Xinjiang University; China. Chinese Academy of Sciences; RepĂșblica de ChinaFil: Zheng, Hongwei. Chinese Academy of Sciences; RepĂșblica de ChinaFil: Zhang, Bo. Chinese Academy of Sciences; RepĂșblica de ChinaFil: Tariq, Akash. Chinese Academy of Sciences; RepĂșblica de ChinaFil: Lv, Guanghui. Xinjiang University; ChinaFil: Zeng, Fanjiang. Chinese Academy of Sciences; RepĂșblica de ChinaFil: Graciano, Corina. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales; Argentina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - La Plata. Instituto de FisiologĂ­a Vegetal. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de FisiologĂ­a Vegetal; Argentina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas; Argentin

    A Dimensional Structure based Knowledge Distillation Method for Cross-Modal Learning

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    Due to limitations in data quality, some essential visual tasks are difficult to perform independently. Introducing previously unavailable information to transfer informative dark knowledge has been a common way to solve such hard tasks. However, research on why transferred knowledge works has not been extensively explored. To address this issue, in this paper, we discover the correlation between feature discriminability and dimensional structure (DS) by analyzing and observing features extracted from simple and hard tasks. On this basis, we express DS using deep channel-wise correlation and intermediate spatial distribution, and propose a novel cross-modal knowledge distillation (CMKD) method for better supervised cross-modal learning (CML) performance. The proposed method enforces output features to be channel-wise independent and intermediate ones to be uniformly distributed, thereby learning semantically irrelevant features from the hard task to boost its accuracy. This is especially useful in specific applications where the performance gap between dual modalities is relatively large. Furthermore, we collect a real-world CML dataset to promote community development. The dataset contains more than 10,000 paired optical and radar images and is continuously being updated. Experimental results on real-world and benchmark datasets validate the effectiveness of the proposed method

    Coordinated Patterns in the Allocation, Composition, and Variability of Multiple Elements Among Organs of Two Desert Shrubs Under Nitrogen Addition and Drought

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    Nutrient allocation closely correlates plant functional traits and development to ecosystem supply services. Desert shrubs maintain the stability of desert ecosystems, whereas the knowledge of how they coordinate nutrients among organs is still limited when responding to differing nitrogen (N) and water regimes. Here we investigated the allocation, composition, and variability of nine elements within organs of Alhagi sparsifolia and Calligonum caput-medusae seedlings under various N addition (0, 3, 6, and 9 gN m−2 year−1) and water regimes (drought versus well-watered). Results showed that plant species identity, organ type, and nitrogen and water treatments significantly affected the concentrations of nine elements independently and interactively (P < 0.05). N addition significantly improved elemental allocation to roots of drought-stressed A. sparsifolia seedlings, whereas N addition of 9.0 gN m−2 year−1 exerted adverse influence on C. caput-medusae. Photosynthetic organs contained more macronutrients, such as N and potassium (K), whereas trace metals accumulated in roots, such as iron (Fe) and manganese (Mn). Soil elemental concentrations were weakly correlated with those in plants. Macroelements in all organs show less variability (coefficient of variation). Coarse root Fe and stem K contents constituted hub traits in plant element networks (PENs) of A. sparsifolia and C. caput-medusae seedlings, respectively, and may play a key role in plant adaptation in desert environments. The looser PEN of A. sparsifolia implied its stronger adaptability than C. caput-medusae. Desert shrubs can coordinate the allocation of multiple elements within and among organs in response to changes in water and N in the environment.Fil: Zhang, Zhihao. Cele National Station Of Observation And Research For Desert-grassland Ecosystems; China. Chinese Academy of Sciences; RepĂșblica de ChinaFil: Chai, Xutian. Chinese Academy of Sciences; RepĂșblica de China. Cele National Station Of Observation And Research For Desert-grassland Ecosystems; ChinaFil: Tariq, Akash. Cele National Station Of Observation And Research For Desert-grassland Ecosystems; China. Chinese Academy of Sciences; RepĂșblica de ChinaFil: Zeng, Fanjiang. Chinese Academy of Sciences; RepĂșblica de China. Cele National Station Of Observation And Research For Desert-grassland Ecosystems; ChinaFil: Graciano, Corina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - La Plata. Instituto de FisiologĂ­a Vegetal. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de FisiologĂ­a Vegetal; ArgentinaFil: Li, Xiangyi. Cele National Station Of Observation And Research For Desert-grassland Ecosystems; China. Chinese Academy of Sciences; RepĂșblica de ChinaFil: Gao, Yanju. Cele National Station Of Observation And Research For Desert-grassland Ecosystems; China. Chinese Academy of Sciences; RepĂșblica de ChinaFil: Ullah, Abd. Cele National Station Of Observation And Research For Desert-grassland Ecosystems; China. Chinese Academy of Sciences; RepĂșblica de Chin

    Perspectives on the Application of Genome-Editing Technologies in Crop Breeding

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    Most conventional and modern crop-improvement methods exploit natural or artificially induced genetic variations and require laborious characterization of the progeny of multiple generations of time-consuming genetic crosses. Genome-editing systems, in contrast, provide the means to rapidly modify genomes in a precise and predictable way, making it possible to introduce improvements directly into elite varieties. Here, we describe the range of applications available to agricultural researchers using existing genome-editing tools. In addition to providing examples of genome-editing applications in crop breeding, we discuss the technical and social challenges faced by breeders using genome-editing tools for crop improvement

    Critical Role of Nutrition in Improving Quality of Care: An Interdisciplinary Call to Action to Address Adult Hospital Malnutrition

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    AbstractThe current era of health care delivery, with its focus on providing high-quality, affordable care, presents many challenges to hospital-based health professionals. The prevention and treatment of hospital malnutrition offers a tremendous opportunity to optimize the overall quality of patient care, improve clinical outcomes, and reduce costs. Unfortunately, malnutrition continues to go unrecognized and untreated in many hospitalized patients. This article represents a call to action from the interdisciplinary Alliance to Advance Patient Nutrition to highlight the critical role of nutrition intervention in clinical care and to suggest practical ways to promptly diagnose and treat malnourished patients and those at risk for malnutrition. We underscore the importance of an interdisciplinary approach to addressing malnutrition both in the hospital and in the acute post-hospital phase. It is well recognized that malnutrition is associated with adverse clinical outcomes. Although data vary across studies, available evidence shows that early nutrition intervention can reduce complication rates, length of hospital stay, readmission rates, mortality, and cost of care. The key is to systematically identify patients who are malnourished or at risk and to promptly intervene. We present a novel care model to drive improvement, emphasizing the following six principles: (1) create an institutional culture where all stakeholders value nutrition; (2) redefine clinicians' roles to include nutrition care; (3) recognize and diagnose all malnourished patients and those at risk; (4) rapidly implement comprehensive nutrition interventions and continued monitoring; (5) communicate nutrition care plans; and (6) develop a comprehensive discharge nutrition care and education plan

    Leaf and whole tree adaptations to mild salinity in field grown Populus euphratica

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    Populus euphratica Oliv. is a highly salt tolerant tree species, and this study represents the first comprehensive investigation of salt tolerance mechanisms of mature trees of P. euphratica in the field. We measured NaCl concentration in xylem sap, NaCl accumulation in leaves, the effect of NaCl on leaf physiological parameters and osmotic adjustment and the allocation and distribution of NaCl between different plant organs on a whole plant level in trees exposed to mild saline groundwater (around 30 mM) in China. Populus euphratica showed three key mechanisms of salt tolerance. The primary mechanism had a strong control over Na+ and Cl- uptake with effective exclusion mechanisms for Cl- with up to 99% of the external NaCl being excluded from the xylem. Secondly, the trees allocated large proportions of NaCl into the leaves, which served as a salt elimination mechanism as the leaves are ultimately shed at the end of the growing season. Thirdly, the trees tolerated high foliar Na+ concentrations through a combination of osmotic adjustment using sucrose and probable sequestering of Na+ in the apoplast. Our results indicate that the control of Na+ and Cl- uptake and the regulation of Na+ and Cl- delivery to the shoot are key to salt tolerance of P. euphratica in the field with tolerance of high Na+ concentrations in leaves being a critical component

    Exogenous Îł-aminobutyric acid (GABA) mitigated salinity-induced impairments in mungbean plants by regulating their nitrogen metabolism and antioxidant potential

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    BackgroundIncreasing soil salinization has a detrimental effect on agricultural productivity.Therefore, strategies are needed to induce salinity-tolerance in crop species for sustainable foodproduction. Îł-aminobutyric acid (GABA) plays a key role in regulating plant salinity stresstolerance. However, it remains largely unknown how mungbean plants (Vigna radiata L.) respondto exogenous GABA under salinity stress.MethodsThus, we evaluated the effect of exogenous GABA (1.5 mM) on the growth and physiobiochemicalresponse mechanism of mungbean plants to saline stress (0-, 50-, and 100 mM [NaCland Na2SO4, at a 1:1 molar ratio]).ResultsIncreased saline stress adversely affected mungbean plants' growth and metabolism. Forinstance, leaf-stem-root biomass (34- and 56%, 31- and 53%, and 27- and 56% under 50- and 100mM, respectively]) and chlorophyll concentrations declined. The carotenoid level increased (10%)at 50 mM and remained unaffected at 100 mM. Hydrogen peroxide (H2O2), malondialdehyde(MDA), osmolytes (soluble sugars, soluble proteins, proline), total phenolic content, andenzymatic activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), peroxidase(POD), glutathione reductase (GTR), and polyphenol oxidation (PPO) were significantlyincreased. In leaves, salinity caused a significant increase in Na+ concentration but a decrease inK+ concentration, resulting in a low K+/Na+ concentration (51- and 71% under 50- and 100- mMstress). Additionally, nitrogen concentration and the activities of nitrate reductase (NR) andglutamine synthetase (GS) decreased significantly. The reduction in glutamate synthase (GOGAT)activity was only significant (65%) at 100 mM stress. Exogenous GABA decreased Na+, H2O2,and MDA concentrations but enhanced photosynthetic pigments, K+ and K+/Na+ ratio, Nmetabolism, osmolytes, and enzymatic antioxidant activities, thus reducing salinity-associatedstress damages, resulting in improved growth and biomass.ConclusionExogenous GABA may have improved the salinity tolerance of mungbean plants by maintaining their morpho-physiological responses and reducing the accumulation of harmfulsubstances under salinity. Future molecular studies can contribute to a better understanding of themolecular mechanisms by which GABA regulates mungbean salinity tolerance

    Coupling relationship of leaf economic and hydraulic traits of alhagi sparsifolia shap. In a hyper-arid desert ecosystem

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    In this study, Alhagi sparsifolia Shap. was used to test the hypothesis that leaf economic and hydraulic traits are coupled in plants in a hyper-arid region. Five economic traits and six hydraulic traits were examined to explore the relationship. Results showed that the stomatal density (SD) on both surfaces was coupled with maximum stomatal conductance to water vapor (gwmax) and leaf tissue density (TD). SD on adaxial surface (SDaba) was significantly positively related to vein density (VD) but negatively related to leaf thickness (LT) and stomatal length on adaxial surface (SLada). Nitrogen concentration based on mass (Nmass) was significantly negatively correlated with leaf mass per area (LMA), LT, and VD, whereas nitrogen concentration based on area (Narea) was significantly positively related to LMA and TD. Mean annual precipitation (MAP) contributed the most to the changes in LT and stomatal length (SL). Soil salt contributed the most to TD, SD, and gwmax. Soli nutrients influenced the most of LMA and VD. Mean annual temperature contributed the most to Nmass and Narea. In conclusion, the economics of leaves coupled with their hydraulic traits provides an economical and efficient strategy to adapt to the harsh environment in hyper-arid regions.Fil: Yin, Hui. University Of Chinese Academy Of Sciences; China. Xinjiang University; China. Xinjiang Institute Of Ecology And Geography Chinese Academy Of Sciences; China. Cele National Station Of Observation And Research For Desert-grassland Ecosystems; ChinaFil: Tariq, Akash. University Of Chinese Academy Of Sciences; China. Cele National Station Of Observation And Research For Desert-grassland Ecosystems; China. Xinjiang Institute Of Ecology And Geography Chinese Academy Of Sciences; ChinaFil: Zhang, Bo. University Of Chinese Academy Of Sciences; China. Cele National Station Of Observation And Research For Desert-grassland Ecosystems; China. Xinjiang Institute Of Ecology And Geography Chinese Academy Of Sciences; ChinaFil: Lv, Guanghui. Xinjiang University; ChinaFil: Zeng, Fanjiang. Cele National Station Of Observation And Research For Desert-grassland Ecosystems; China. Xinjiang Institute Of Ecology And Geography Chinese Academy Of Sciences; China. University Of Chinese Academy Of Sciences; ChinaFil: Graciano, Corina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Centro CientĂ­fico TecnolĂłgico Conicet - La Plata. Instituto de FisiologĂ­a Vegetal. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de FisiologĂ­a Vegetal; ArgentinaFil: Santos, Mauro. Universidade Federal de Pernambuco; BrasilFil: Zhang, Zhihao. University Of Chinese Academy Of Sciences; China. Xinjiang Institute Of Ecology And Geography Chinese Academy Of Sciences; China. Cele National Station Of Observation And Research For Desert-grassland Ecosystems; ChinaFil: Wang, Peng. Cele National Station Of Observation And Research For Desert-grassland Ecosystems; China. Xinjiang Institute Of Ecology And Geography Chinese Academy Of Sciences; ChinaFil: Mu, Shuyong. Xinjiang Institute Of Ecology And Geography Chinese Academy Of Sciences; Chin
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