Indirect effects of primary prey population dynamics on alternative prey

We develop a theory of generalist predation showing how alternative prey species are affected by changes in both mean abundance and variability (coefficient of variation) of their predator's primary prey. The theory is motivated by the indirect effects of cyclic rodent populations on ground-breeding birds, and developed through progressive analytic simplifications of an empirically-based model. It applies nonetheless to many other systems where primary prey have fast life-histories and can become locally superabundant, which facilitates impact on alternative prey species. In contrast to classic apparent competition theory based on symmetric interactions, our results suggest that predator effects on alternative prey should generally decrease with mean primary prey abundance, and increase with primary prey variability (low to high CV) - unless predators have strong aggregative responses, in which case these results can be reversed. Approximations of models including predator dynamics (general numerical response with possible delays) confirm these results but further suggest that negative temporal correlation between predator and primary prey is harmful to alternative prey. We find in general that predator numerical responses are crucial to predict the response of ecosystems to changes in key prey species exhibiting outbreaks, and extend the apparent competition/mutualism theory to asymmetric interactions

Stellar clusters in the inner Galaxy and their correlation with cold dust emission

Stars are born within dense clumps of giant molecular clouds, constituting young stellar agglomerates known as embedded clusters, which only evolve into bound open clusters under special conditions. We statistically study all embedded clusters (ECs) and open clusters (OCs) known so far in the inner Galaxy, investigating particularly their interaction with the surrounding molecular environment and the differences in their evolution. We first compiled a merged list of 3904 clusters from optical and infrared clusters catalogs in the literature, including 75 new (mostly embedded) clusters discovered by us in the GLIMPSE survey. From this list, 695 clusters are within the Galactic range |l| < 60 deg and |b| < 1.5 deg covered by the ATLASGAL survey, which was used to search for correlations with submm dust continuum emission tracing dense molecular gas. We defined an evolutionary sequence of five morphological types: deeply embedded cluster (EC1), partially embedded cluster (EC2), emerging open cluster (OC0), OC still associated with a submm clump in the vicinity (OC1), and OC without correlation with ATLASGAL emission (OC2). Together with this process, we performed a thorough literature survey of these 695 clusters, compiling a considerable number of physical and observational properties in a catalog that is publicly available. We found that an OC defined observationally as OC0, OC1, or OC2 and confirmed as a real cluster is equivalent to the physical concept of OC (a bound exposed cluster) for ages in excess of ~16 Myr. Some observed OCs younger than this limit can actually be unbound associations. We found that our OC and EC samples are roughly complete up to ~1 kpc and ~1.8 kpc from the Sun, respectively, beyond which the completeness decays exponentially. Using available age estimates for a few ECs, we derived an upper limit of 3 Myr for the duration of the embedded phase... (Abridged)Comment: 39 pages, 9 figures. Accepted for publication in A&A on Sept 16, 2013. The catalog will be available at the CDS after official publication of the articl

Analisis Yuridis Tentang Hukum Asuransi Dalam Transaksi Electronic Commerce Melalui Perspektif Kitab Undang-undang Hukum Dagang

Seiring dengan perkembangan teknologi dan informasi di dunia, berbagai hal baru muncul di dalam kehidupan kita sehari-hari. Salah satunya adalah konsep jual beli secara online melalui internet dengan menggunakan e-commerce . Dengan e-commerce konsep jual beli tradisonal yang mempertemukan pembeli dan penjual dalam satu ruangan berubah menjadi konsep jual beli jarak jauh atau telemarketing. Dengan adanya konsep ini, tentu saja baik penjual dan pembeli akan merasa di untungkan, karena transaksi jual beli yang terjadi dapat dilakukan 24 jam penuh dengan tidak dibatasi oleh wilayah tertentu. Akan tetapi selain memberikan keuntungan, tentu saja konsep jual beli jarak jauh melalui e-commerce juga dapat menimbulkan banyak resiko kerugian, salah satunya adalah serangan cyber crime yang dapat menyebabkan penyalahgunaan data para pihak dalam e-commerce sehingga mengalami kerugian. Penelitian dalam Artikel ilmiah ini dilakukan untuk dapat mengetahui dan menganalisis bagaimana Kitab Undang-Undang Hukum Dagang (KUHD) mengatur Asuransi yang berhubungan dengan transaksi elektronik melalui internet (e-commerce), mengetahui dan menganalisis pihak - pihak yang dapat dijadikan subyek dan obyek asuransi dalam transaksi elektronik melalui internet (ecommerce), serta menganalisis penyebab perlunya asuransi dalam transaksi electronic commerce diatur secara khusus di dalam peraturan Perundang-undangan di Indonesia. Metode penelitian yang di pakai dalam penulisan Artikel ilmiah ini adalah metode Penelitian hukum normatif yang bertujuan untuk menemukan landasan hukum yang jelas dalam meletakkan persoalan yang diangkat, dalam perspektif Kitab Undang-Undang Hukum Dagang, khususnya yang terkait dengan masalah penerapan asuransi dalam transaksi e-commerce. Berdasarkan pembahasan terhadap hasil penelitian terungkap bahwa dari pengertian dan batasan tentang asuransi di dalam KUHD, transaksi e-commerce merupakan obyek yang dapat di asuransikan, karena segala kegiatan didalam transaksi e-commerce, dapat menimbulkan kehilangan atau kerusakan bagi para pihak yang ada didalamnya. Pengaturan asuransi mengenai e-commerce di dalam KUHD sebenarnya perlu diatur secara rinci, sehingga pemerintah hendaknya melakukan revisi Undang-Undang Nomor 2 Tahun 1992 tentang Usaha Pengasuransian, sehingga dapat memberikan pengaturan jelas mengenai asuransi dalam transaksi bisnis e-commerce atau cyber insurance

Constitutional Law - Separation of Church and State - Bible Reading in the Public Schools

The plaintiff, as a citizen, taxpayer, and parent of school children, sought an injunction to restrain the defendant school board from allowing school teachers to read the Bible aloud to students as required by a Tennessee statute. The plaintiff contended that this practice was offensive to him and in violation of the Tennessee and United States Constitutions. The trial court sustained defendant\u27s demurrer. On appeal, held, affirmed. The statute violates neither constitution because it is not an interference with students\u27 or parents\u27 religious beliefs. Carden v. Bland, (Tenn. 1956) 288 S. W. (2d) 718

Effect of pine bark and compost on the biological denitrification process of non-hazardous landfill leachate: Focus on the microbiology

In an attempt to optimize the cost-efficiency of landfill leachate treatment by biological denitrification process, our study focused on finding low-cost alternatives to traditional expensive chemicals such as composted garden refuse and pine bark, which are both available in large amount in South African landfill sites. The overall objective was to assess the behaviour of the bacterial community in relation to each substrate while treating high strength landfill leachates. Denitrification processes in fixed bed reactors were simulated at laboratory scale using anaerobic batch tests with immature compost and pine bark. High strength leachate was simulated using a solution of water and nitrate at a concentration of 500 mg l−1. Results suggest that pine bark released large amounts of phenolic compounds and hydroxylated benzene rings, which both can delay the acclimatization time and inhibit the biological denitrification (only 30% efficiency). Furthermore, presence of potential pathogens like Enterobacter and Pantoea agglomerans prevents the applicability of the pine bark in full-scale operations. On the other hand, lightly composted garden refuse (CGR) offered an adequate substrate for the formation of a biofilm necessary to complete the denitrification process (total nitrate removal observed within 7 days). CGR further contributed to a rapid establishment of an active consortium of denitrifiers including Acinetobacter, Rhizobium, Thermomonas, Rheinheimera, Phaeospirillum and Flavobacterium. Clearly the original composition, nature, carbon to nitrogen ratio (C/N) and degree of maturity and stability of the substrates play a key role in the denitrification process, impacting directly on the development of the bacterial population and, therefore, on the long-term removal efficiency

Dynamical Interactions of Planetary Systems in Dense Stellar Environments

We study dynamical interactions of star--planet binaries with other single stars. We derive analytical cross sections for all possible outcomes, and confirm them with numerical scattering experiments. We find that a wide mass ratio in the binary introduces a region in parameter space that is inaccessible to comparable-mass systems, in which the nature of the dynamical interaction is fundamentally different from what has traditionally been considered in the literature on binary scattering. We study the properties of the planetary systems that result from the scattering interactions for all regions of parameter space, paying particular attention to the location of the "hard--soft" boundary. The structure of the parameter space turns out to be significantly richer than a simple statement of the location of the "hard--soft" boundary would imply. We consider the implications of our findings, calculating characteristic lifetimes for planetary systems in dense stellar environments, and applying the results to previous analytical studies, as well as past and future observations. Recognizing that the system PSR B1620-26 in the globular cluster M4 lies in the "new" region of parameter space, we perform a detailed analysis quantifying the likelihood of different scenarios in forming the system we see today.Comment: Accepted for publication in ApJ. Minor changes to reflect accepted version. 14 pages, 14 figure

High Orbital Eccentricities of Extrasolar Planets Induced by the Kozai Mechanism

One of the most remarkable properties of extrasolar planets is their high orbital eccentricities. Observations have shown that at least 20% of these planets, including some with particularly high eccentricities, are orbiting a component of a wide binary star system. The presence of a distant binary companion can cause significant secular perturbations to the orbit of a planet. In particular, at high relative inclinations, a planet can undergo a large-amplitude eccentricity oscillation. This so-called "Kozai mechanism" is effective at a very long range, and its amplitude is purely dependent on the relative orbital inclination. In this paper, we address the following simple question: assuming that every host star with a detected giant planet also has a (possibly unseen, e.g., substellar) distant companion, with reasonable distributions of orbital parameters and masses, how well could secular perturbations reproduce the observed eccentricity distribution of planets? Our calculations show that the Kozai mechanism consistently produces an excess of planets with very high (e >0.6) and very low (e < 0.1) eccentricities. The paucity of near-circular orbits in the observed sample cannot be explained solely by the Kozai mechanism, because, even with high enough inclinations, the Kozai mechanism often fails to produce significant eccentricity perturbations when there are other competing sources of orbital perturbations on secular timescales, such as general relativity. On the other hand, the Kozai mechanism can produce many highly eccentric orbits. Indeed the overproduction of high eccentricities observed in our models could be combined with plausible circularizing mechanisms (e.g., friction from residual gas) to create more intermediate eccentricities (e=0.1-0.6).Comment: 24 pages, 6 figures, ApJ, in press, minor changes to reflect the accepted versio

Pure Asymmetric Quantum MDS Codes from CSS Construction: A Complete Characterization

Using the Calderbank-Shor-Steane (CSS) construction, pure $q$-ary asymmetric quantum error-correcting codes attaining the quantum Singleton bound are constructed. Such codes are called pure CSS asymmetric quantum maximum distance separable (AQMDS) codes. Assuming the validity of the classical MDS Conjecture, pure CSS AQMDS codes of all possible parameters are accounted for.Comment: Change in authors' list. Accepted for publication in Int. Journal of Quantum Informatio