Higher absorbed solar radiation partly offset the negative effects of water stress on the photosynthesis of Amazon forests during the 2015 drought

Amazon forests play an important role in the global carbon cycle and Earth\u27s climate. The vulnerability of Amazon forests to drought remains highly controversial. Here we examine the impacts of the 2015 drought on the photosynthesis of Amazon forests to understand how solar radiation and precipitation jointly control forest photosynthesis during the severe drought. We use a variety of gridded vegetation and climate datasets, including solar-induced chlorophyll fluorescence (SIF), photosynthetic active radiation (PAR), the fraction of absorbed PAR (APAR), leaf area index (LAI), precipitation, soil moisture, cloud cover, and vapor pressure deficit (VPD) in our analysis. Satellite-derived SIF observations provide a direct diagnosis of plant photosynthesis from space. The decomposition of SIF to SIF yield (SIFyield) and APAR (the product of PAR and fPAR) reveals the relative effects of precipitation and solar radiation on photosynthesis. We found that the drought significantly reduced SIFyield, the emitted SIF per photon absorbed. The higher APAR resulting from lower cloud cover and higher LAI partly offset the negative effects of water stress on the photosynthesis of Amazon forests, leading to a smaller reduction in SIF than in SIFyield and precipitation. We further found that SIFyield anomalies were more sensitive to precipitation and VPD anomalies in the southern regions of the Amazon than in the central and northern regions. Our findings shed light on the relative and combined effects of precipitation and solar radiation on photosynthesis, and can improve our understanding of the responses of Amazon forests to drought

Effects of Feral Cats on the Evolution of Antipredator Behaviors in the Aegean Wall Lizard (Pordarcis erhardii)

Exotic predators such as feral cats (Felis catus), have been the driving force behind the extinction of many endemic species of island mammals, birds and reptiles. Island endemics appear to be exceptionally susceptible to invasive predators because of small population size and frequent lack of anti-predator defenses. The goal of this study was to determine the impacts of feral cats on the island populations of Aegean Wall lizards (Podarcis erhardii, Lacertidae) in relationship to the expression of anti-predator behaviors. I estimated lizard population densities in areas with low cat density sites (LCD) versus high cat density (HCD) sites by conducting 100-m transect along dry-stone walls, on the island of Naxos, as well as on surrounding islets (Cyclades, Greece). Degree of expression of antipredator behaviors was determined by measuring flight initiation distance (FID) and rates of tail autotomy both in the field and in the lab for six populations in HCD, LCD sites and four satellite islets without cat presence. I also staged controlled encounters with mounted cats decoys and quantified escaping responses from lizards from these populations. I found that feral cats had a strong negative effect on lizard population densities. Lizards adapted their antipredator behaviors in response to cat predation by extending their FIDs, increasing their capacity for tail autotomy, and by staying closer to refugia. In laboratory predation simulations, lizards from cat-free islets had significantly shorter FIDs than LCD site lizards and in particular than HCD site lizards. Furthermore, some unique islet behaviors, presumably evolved in response to lack of predators and to ameliorate chronic conditions of food shortage, appear to render islet lizards strongly susceptible to cat predation. These behaviors include rarely utilizing available refugia, and moving towards anything new, including cat decoys. Nonetheless, I found that repeated exposures over three trials led to significant increases in FIDs for all populations, indicating at least some behavioral plasticity. My results suggest that although lizards may adapt their antipredator behaviors to cope with introduced predators, this offers at best only partial protection, so that there remains strong concern about their survival in the face of expanding feral cat populations.Master of ScienceNatural Resources and EnvironmentUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/90870/1/Binbin_Final_Thesis_2012.pd

Comparison of bacterial inactivation efficiency and disinfection byproduct formation from different disinfection processes

Formation of disinfection byproducts (DBPs) during Escherichia coli K12 and Pseudomonas aeruginosa PAO1 inactivation under four disinfection processes, including chlorination, chloramination, photo-Fenton reaction, and TiO2/UV photocatalytic inactivation were examined. Factors of pH (5 or 8) and different disinfectant dosages were also investigated in order to balance the risks of DBP formation and bacterial cell viability in the four treatment processes. Chlorination had the fastest bacterial inactivation whereas chloramination, photo-Fenton, and TiO2/UV requiring longer contact times to achieve the same inactivation efficiency. In spite of the lag phase in the treatment processes, both photo-Fenton and TiO2/UV achieved 100% bacteria reduction after 80-min exposure, exceeding effectiveness of the chlorination (5.6 log reduction) and chloramination (4.4 log reduction). In addition, chlorination had the highest trihalomethanes (THMs) of 5.77 ± 0.21 μg/L and haloacetonitriles (HANs) of 1.02 ± 0.15 μg/L, followed by chloramination (with THMs of 1.37 ± 0.03 μg/L and HANs of 0.17 ± 0.04 μg/L). No THMs or HANs was detected in photo-Fenton or TiO2/UV processes. In general, the risks of DBP and bacterial cells in finished water can be reduced through efficient operational conditions: Acidic pH condition for chlorination, chloramination, and TiO2/UV photocatalytic inactivation. For photo-Fenton reaction, no DBPs formed with equal similar cell viability reduction observed under pH range of 5 - 8

LogoNet: a fine-grained network for instance-level logo sketch retrieval

Sketch-based image retrieval, which aims to use sketches as queries to retrieve images containing the same query instance, receives increasing attention in recent years. Although dramatic progress has been made in sketch retrieval, few efforts are devoted to logo sketch retrieval which is still hindered by the following challenges: Firstly, logo sketch retrieval is more difficult than typical sketch retrieval problem, since a logo sketch usually contains much less visual contents with only irregular strokes and lines. Secondly, instance-specific sketches demonstrate dramatic appearance variances, making them less identifiable when querying the same logo instance. Thirdly, there exist several sketch retrieval benchmarking datasets nowadays, whereas an instance-level logo sketch dataset is still publicly unavailable. To address the above-mentioned limitations, we make twofold contributions in this study for instance-level logo sketch retrieval. To begin with, we construct an instance-level logo sketch dataset containing 2k logo instances and exceeding 9k sketches. To our knowledge, this is the first publicly available instance-level logo sketch dataset. Next, we develop a fine-grained triple-branch CNN architecture based on hybrid attention mechanism termed LogoNet for accurate logo sketch retrieval. More specifically, we embed the hybrid attention mechanism into the triple-branch architecture for capturing the key query-specific information from the limited visual cues in the logo sketches. Experimental evaluations both on our assembled dataset and public benchmark datasets demonstrate the effectiveness of our proposed network

Computational Fluid Dynamics Analysis into The Improvement of Seakeeping Characteristics of A Fast Craft Using AXE-Bow

It is obviously understood that hull shape affects the movement characteristics and operability of a ship. There are several ways which can be conducted in order to improve the operability of a ship one of those is by improving ship bow. Recent development known as AXE-Bow was introduced by Delft University of Technology in collaboration with DAMEN Shipyard, in the Netherlands. It was reported that the AXE-Bow can improve the seakeeping characteristics of the vessel at higher speed (Froude number above 0.60), such as reduce vertical acceleration. The current work is carried out numerically using Computational Fluid Dynamics (CFD) approach together with the use of CFD code called Hydrostar provided by Bureau Veritas (BV). The overall results showed that there are good agreement between CFD method and the work by Delft University of University and DAMEN Shipyard. Comparative studies were also carried out with published data and demonstrated similar finding

Enhancing the Unified Streaming and Non-streaming Model with Contrastive Learning

The unified streaming and non-streaming speech recognition model has achieved great success due to its comprehensive capabilities. In this paper, we propose to improve the accuracy of the unified model by bridging the inherent representation gap between the streaming and non-streaming modes with a contrastive objective. Specifically, the top-layer hidden representation at the same frame of the streaming and non-streaming modes are regarded as a positive pair, encouraging the representation of the streaming mode close to its non-streaming counterpart. The multiple negative samples are randomly selected from the rest frames of the same sample under the non-streaming mode. Experimental results demonstrate that the proposed method achieves consistent improvements toward the unified model in both streaming and non-streaming modes. Our method achieves CER of 4.66% in the streaming mode and CER of 4.31% in the non-streaming mode, which sets a new state-of-the-art on the AISHELL-1 benchmark.Comment: Accepted by INTERSPEECH 202

Heat Transfer Correlations of Supercritical Fluids

The drastic changes of thermophysical properties in the pseudo-critical region of supercritical fluids bring very big challenges to the traditional Dittus-Boelter-type heat transfer correlations. In this chapter, we will talk about the principles and applications of two kinds of heat transfer correlations of supercritical fluids: the empirical type and the semiempirical type. For the empirical correlations, the modification methods taking into account the variable properties and body force effects will be introduced. We will focus on the proposal of nondimensional parameters describing the buoyancy effect and flow acceleration; while for the semiempirical ones, we mainly talk about the new kind of correlation which is based on the momentum and energy conservations in the mixed convective flow