2,058 research outputs found

    Amortized Rotation Cost in AVL Trees

    Full text link
    An AVL tree is the original type of balanced binary search tree. An insertion in an nn-node AVL tree takes at most two rotations, but a deletion in an nn-node AVL tree can take Θ(logn)\Theta(\log n). A natural question is whether deletions can take many rotations not only in the worst case but in the amortized case as well. A sequence of nn successive deletions in an nn-node tree takes O(n)O(n) rotations, but what happens when insertions are intermixed with deletions? Heaupler, Sen, and Tarjan conjectured that alternating insertions and deletions in an nn-node AVL tree can cause each deletion to do Ω(logn)\Omega(\log n) rotations, but they provided no construction to justify their claim. We provide such a construction: we show that, for infinitely many nn, there is a set EE of {\it expensive} nn-node AVL trees with the property that, given any tree in EE, deleting a certain leaf and then reinserting it produces a tree in EE, with the deletion having done Θ(logn)\Theta(\log n) rotations. One can do an arbitrary number of such expensive deletion-insertion pairs. The difficulty in obtaining such a construction is that in general the tree produced by an expensive deletion-insertion pair is not the original tree. Indeed, if the trees in EE have even height kk, 2k/22^{k/2} deletion-insertion pairs are required to reproduce the original tree

    Discussion of “effect of exercise-induced dehydration on circulatory markers of oxidative damage and antioxidant capacity”

    Get PDF
    We read with great interest a recent article by Georgescu et al. (2017) entitled “Effect of exercise-induced dehydration on circulatory markers of oxidative damage and antioxidant capacity”. The authors aimed to investigate effects of hydration and rehydration by using sensitive indirect measures of oxidative stress and the antioxidant capacity response. In this study, they evaluated concentrations of plasma osmolality, Trolax equivalent antioxidant capacity (TEAC), and ferric reducing ability of plasma (FRAP) in a sample of athletes during pre-exercise, immediately postexercise, and 1 h after full rehydration. As stated in statistical analysis and also abstract of the article, the authors used 1-way ANOVA to compare differences in means of numerical variables (i.e., concentrations of plasma osmolality, TEAC, and FRAP) of different time-points of measurement. Since they investigated the same sample of participants in each group during different time-points (i.e., pre-exercise, immediately postexercise, and 1 h after full rehydration), their measurements are completely dependent (Farrokhi and Peykanpour 2017a; Farrokhi and Shirian 2017; Farrokhi et al. 2017). ANOVA and Kruskal–Wallis test are used for comparison of the means of more than 2 independent groups (Gaddis 1998; Farrokhi 2017b; Farrokhi and Arjaki 2017; Farrokhi and Peykanpour 2017b). Therefore, after assessment of the normal distribution of studied quantitative variables, including concentrations of plasma osmolality, TEAC, and FRAP, the authors must use repeated-measures ANOVA or Friedman test for comparison of the means of each variable at pre-exercise, immediately postexercise, and 1 h after full rehydration (Farrokhi 2017a; Farrokhi and Amani-Beni 2017). Furthermore, they must use Wilcoxon test and paired t test for comparison of concentrations of plasma osmolality, TEAC, and FRAP between 2 time-points of measurement

    Economics and Biodiversity in Intensively Managed Agro-Ecosystems

    Get PDF
    This paper explores the dynamic effects of biodiversity conservation on agricultural production in the context of specialised intensive farming systems. The focus is on the analysis of the dynamic effects of changes in the levels of agrobiodiversity, on technical change and productivity in intensive agricultural systems. A theoretical model is used to derive hypotheses regarding these linkages that are empirically tested using a stochastic production frontier model with data from a panel of UK cereal farms for the period 1989-2000. The results suggest that the increased agrobiodiversity has positively helped to shift the production frontier outwards. This indicates that the evolution of an intensive agricultural system to less intensive use of inputs can be consistent with non-decreasing output levels and an enhancement of biodiversity in agricultural landscapes.Agrobiodiversity, Intensive Agriculture, Productivity, Technical change, Resource /Energy Economics and Policy, Q12, Q16, Q24,

    The Economics of Biodiversity Conservation in Agricultural Transition

    Get PDF
    This paper explores the dynamic effects of biodiversity conservation on agricultural production in the context of specialised intensive farming systems that may be in transition towards more sustainable farming. The focus is on the analysis of the dynamic effects of changes in the levels of agrobiodiversity, on technical change and productivity in intensive agricultural systems. A theoretical model is used to derive hypotheses regarding these linkages that are empirically tested using a stochastic production frontier model with data from a panel of UK cereal farms for the period 1989-2000. The results suggest that the increased agrobiodiversity has positively helped to shift the production frontier outwards. This indicates that agricultural transition from more to less intensive agricultural systems can be consistent with non-decreasing output levels and an enhancement of biodiversity in agricultural landscapes.agrobiodiversity, intensive agriculture, productivity, technical change, Environmental Economics and Policy, Q12, Q16, Q24,

    Frequency comb vernier spectroscopy in the near infrared

    Full text link
    We perform femtosecond frequency comb vernier spectroscopy in the near infrared with a femtosecond Er doped fiber laser, a scanning high-finesse cavity and an InGaAs camera. By utilizing the properties of a frequency comb and a scanning high-finesse cavity such spectroscopy provides broad spectral bandwidth, high spectral resolution, and high detection sensitivity on a short time scale. We achieved an absorption sensitivity of ~8E-8 cm-1Hz-1/2 corresponding to a detection limit of ~70 ppbv for acetylene, with a resolution of ~1.1 GHz in single images taken in 0.5 seconds and covering a frequency range of ~5 THz. These measurements have broad applications for sensing other greenhouse gases in this fingerprint near IR region with a simple apparatus.Comment: 14 pages, 5 figure

    Manajemen dana zakat di Badan Amil Zakat daerah (BAZDA) kabupaten Kendal

    Get PDF
    Zakat sebagai rukun Islam yang ke tiga merupakan kewajiban setiap muslim yang mampu untuk membayarnya dan diperuntukkan bagi mereka yang berhak menerimanya. Pengelolaan yang baik zakat merupakan sumber dana potensial yang dimanfaatkan untuk memajukan kesejahteraan umum bagi seluruh masyarakat. Bulan Oktober 2012, Sebanyak 397.540 dari 1,2 juta jumlah warga di Kabupaten Kendal Jawa Tengah, tergolong miskin. Jumlah ini lebih banyak atau naik sekitar 40 persen, dibandingkan data terakhir pada tahun 2010. Kenaikan itu disebabkan banyaknya warga Kendal yang sudah tidak bekerja, karena ada putus hubungan kerja (PHK) yang dilakukan oleh pabrik tempatnya bekerja. Melihat kenyataan ini, maka aplikasi zakat perlu diterapkan apalagi mayoritas penduduk Indonesia beragama Islam. Namun di sisi lain, potensi zakat yang berhasil dihimpun oleh lembaga zakat masih jauh dari target. Hal ini menuntut adanya pengaturan dana yang professional sehingga potensi dana umat yang masih terbatas ini bisa dimanfaatkan secara optimal. Atas dasar inilah, penulis tertarik melakukan penelitian di Badan Amil Zakat Daerah (BAZDA) Kabupaten Kendal dengan tujuan untuk mengetahui manajemen dana di lembaga ini, baik dari aspek penghimpunan, pendistribusian, dan pendayagunaannya serta kendala-kendala yang dihadapi oleh Badan Amil Zakat ini. Metode analisis data yang digunakan dalam penelitian ini adalah analisis deskriptif kualitatif. Metode ini dipilih karena didasarkan atas desain penelitian, pendekatan penelitian serta sumber data yang digali sebagai data penelitian. Dalam penelitian ini dilakukan analisa antara teori yang sudah ada dengan realitas di lapangan, yaitu mengkaji bagaimana aplikasi manajemen pengelolaan dana zakat dan praktek pengelolaan yang ada di BAZDA Kendal mulai dari aspek penghimpunan, pendistribusian, dan pendayagunaan dana yang ada. Sumber data yang digunakan adalah data primer yaitu wawancara, dan data sekunder yaitu berupa buku-buku dan internet. Teknik pengumpulan dalam penelitian ini menggunakan wawancara dan dokumentasi. Hasil penelitian ini menunjukkan bahwa dari sisi penghimpunan di BAZDA Kabupaten Kendal Penghimpunan di BAZDA Kabupaten Kendal menggunakan Metode Fundraising Langsung (Direct Fundraising) yaitu mengirimkan pemberitahuan penghimpunan zakat melalui surat yang dikirim ke unit pengelola zakat (UPZ), telefundrising yaitu melalui via telephone dan presentasi langsung melalui kegiatan seminar dan sosialisasi. Metode Fundraising Tidak Langsung (Indirect fundraising) yaitu melalui perantara bank, melalui referensi dari berbagai instansi/perusahaan yang ada di Kendal dan mediasi para tokoh yang memiliki pengaruh dalam penghimpunan zakat. Pendistribusian zakat yang pertama dilakukan secara konsumtif yaitu penyaluran dana zakat yang di berikan langsung kepada mustahiq berupa paket sembako dan uang. Kedua, pendistribusian secara produktif (Pendayagunaan) diberikan dalam bentuk bantuan modal berupa pemberian pinjaman bergulir Rp 1.000.000 tanpa bunga dengan angsuran Rp 100.000 selama 9 kali untuk meningkatkan hasil usah

    Review of En-Face Choroidal Imaging Using Spectral-Domain Optical Coherence Tomography

    Get PDF
    Investigations of choroidal vasculature have been of particular interest given choroidal vascular dysfunction are thought to be related with a number pathologic conditions such as central serous chorioretinopathy and various forms of AMD, including polypoidal choroidal vasculopathy. On the other hand, en face imaging of the choroid allows an exceptional alternative to histopathologic evaluation of the choroid, and can be used to quantify choroidal vascular structures. Our former study verified differences in the macular choroid in AMD and control patients previously noted on histopathologic studies. The use of phase-resolved approaches in larger population longitudinal studies reveal the sequence of RPE and choroidal changes in the pathogenesis of various AMD subtypes, which cannot be done using histopathology. Issues with lateral resolution of the OCT system in measuring choriocapillaris size could be solved by incorporating the axial dimension of the choriocapillaris into choriocapilaris diameter assessment (assuming the choriocapillaris are round in vivo), and by correcting for anisometric pixel resolution. Forthcoming studies are required to determine whether areas of choriocapillaris correlate with areas of RPD lesions

    Diet composition and feeding habits of Acetes japonicus (Decapoda: Sergestidae) in estuarine waters of Tanjung Dawai, Kedah, Malaysia

    Get PDF
    This study describes the diet composition and feeding habits of sergestid shrimps Acetes japonicas. The stomach contents of 330 specimens, captured from the Estuary of Tanjung Dawai, Kedah from June 2008 - May 2009 were analysed. Analysis on the percentage of numerical abundance (Ci) showed that plant matter (28.18%) and crustacean appendages (18.70%) as the two highest values amongst the eight categories of feeding items. In addition, percentage frequency of occurrence (Fpi) values of phytoplankton, zooplankton, algae, plant matter, appendages of crustacean, debris, unidentified items and sand-mud were 3.54%, 7.05%, 5.07%, 27.44%, 17.42%, 15.80%, 8.94% and 19.81% respectively. Based on the food composition found in the stomach, it could be concluded that A. japonicus is a bottom feeder omnivorous
    corecore