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

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

Energy Efficient Power Allocation for Distributed Antenna System over Shadowed Nakagami Fading Channel

In this paper, the energy efficiency (EE) of downlink distributed antenna system (DAS) with multiple receive antennas is investigated over composite fading channel that takes the path loss, shadow fading and Nakagami-m fading into account. Our aim is to maximize EE which is defined as the ratio of the transmission rate to the total consumed power under the constraints of maximum transmit power of each remote antenna. According to the definition of EE and using the upper bound of average EE, the optimized objective function is provided. Based on this, utilizing Karush-Kuhn-Tucker (KKT) conditions and mathematical derivation, a suboptimal energy efficient power allocation (PA) scheme is developed, and closed-form PA coefficients are obtained. The developed scheme has the EE performance close to the existing optimal scheme. Moreover, it has relatively lower complexity than the existing scheme because only the statistic channel information and less iteration are required. Besides, it includes the scheme in composite Rayleigh channel as a special case. Simulation results show the effectiveness of the developed scheme

The Electronics and Data Acquisition System for the PandaX-I Dark Matter Experiment

We describe the electronics and data acquisition system used in the first phase of the PandaX experiment -- a 120 kg dual-phase liquid xenon dark matter direct detection experiment in the China Jin-Ping Underground Laboratory. This system utilized 180 channels of commercial flash ADC waveform digitizers. This system achieved low trigger threshold ($<$1 keV electron-equivalent energy) and low deadtime data acquistion during the entire experimental run.Comment: 12 pages, 6 figures, version as accepted by JINS

Energy transfer analysis for capacitor voltage balancing of modular multilevel converters

Voltage balancing between sub-module (SM) capacitors is essential for reliable operation of the modular multilevel converter (MMC). To facilitate design and understanding of the balancing controllers, this study presents an energy transfer analysis for MMC, which explains how the energy can be independently transmitted from/to one phase, between the upper and lower arms, and among the SMs, of an MMC. Using this analysis, the variables which can be utilized to achieve capacitor voltage balancing are identified. Validity of this study has been verified by experimental results based on a three-phase MMC prototype

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

Five-S-isotope evidence of two distinct mass-independent sulfur isotope effects and implications for the modern and Archean atmospheres.

The signature of mass-independent fractionation of quadruple sulfur stable isotopes (S-MIF) in Archean rocks, ice cores, and Martian meteorites provides a unique probe of the oxygen and sulfur cycles in the terrestrial and Martian paleoatmospheres. Its mechanistic origin, however, contains some uncertainties. Even for the modern atmosphere, the primary mechanism responsible for the S-MIF observed in nearly all tropospheric sulfates has not been identified. Here we present high-sensitivity measurements of a fifth sulfur isotope, stratospherically produced radiosulfur, along with all four stable sulfur isotopes in the same sulfate aerosols and a suite of chemical species to define sources and mechanisms on a field observational basis. The five-sulfur-isotope and multiple chemical species analysis approach provides strong evidence that S-MIF signatures in tropospheric sulfates are concomitantly affected by two distinct processes: an altitude-dependent positive 33S anomaly, likely linked to stratospheric SO2 photolysis, and a negative 36S anomaly mainly associated with combustion. Our quadruple stable sulfur isotopic measurements in varying coal samples (formed in the Carboniferous, Permian, and Triassic periods) and in SO2 emitted from combustion display normal 33S and 36S, indicating that the observed negative 36S anomalies originate from a previously unknown S-MIF mechanism during combustion (likely recombination reactions) instead of coal itself. The basic chemical physics of S-MIF in both photolytic and thermal reactions and their interplay, which were not explored together in the past, may be another ingredient for providing deeper understanding of the evolution of Earth's atmosphere and life's origin