101,823 research outputs found
Mining e-mail content for author identification forensics
No full textWe describe an investigation into e-mail content mining for author identification, or authorship attribution, for the purpose of forensic investigation. We focus our discussion on the ability to discriminate between authors for the case of both aggregated e-mail topics as well as across different email topics. An extended set of e-mail document features including structural characteristics and linguistic patterns were derived and, together with a Support Vector Machine learning algorithm, were used for mining the e-mail content. Experiments using a number of e-mail documents generated by different authors on a set of topics gave promising results for both aggregated and multi-topic author categorisation
Hamiltonian Learning via Shadow Tomography of Pseudo-Choi States
No full textWe introduce a new approach to learn Hamiltonians through a resource that we
call the pseudo-Choi state, which encodes the Hamiltonian in a state using a
procedure that is analogous to the Choi-Jamiolkowski isomorphism. We provide an
efficient method for generating these pseudo-Choi states by querying a time
evolution unitary of the form and its inverse, and show that for a
Hamiltonian with terms the Hamiltonian coefficients can be estimated via
classical shadow tomography within error in the -norm using
queries to the state
preparation protocol, where . We
further show an alternative approach that eschews classical shadow tomography
in favor of quantum mean estimation that reduces this cost (at the price of
many more qubits) to .
Additionally, we show that in the case where one does not have access to the
state preparation protocol, the Hamiltonian can be learned using
copies of the
pseudo-Choi state. The constant depends on the norm of the
Hamiltonian, and the scaling in terms of can be improved quadratically
if using pseudo-Choi states of the normalized Hamiltonian. Finally, we show
that our learning process is robust to errors in the resource states and to
errors in the Hamiltonian class. Specifically, we show that if the true
Hamiltonian contains more terms than we believe are present in the
reconstruction, then our methods give an indication that there are Hamiltonian
terms that have not been identified and will still accurately estimate the
known terms in the Hamiltonian.Comment: 59 pages, 3 figures. Pages 45-59 contain appendice
Produção e qualidade de pak choi cultivado em diferentes sistemas hidropônicos e condutividades elétricas
No full textPak choi is a leafy vegetable rich in important bioactives for human health. As this vegetable is cultivated predominantly in Europe and Asia, there is little information about it in the Brazilian literature. The aim of this study was to evaluate the production and quality of pak choi cultivated in hydroponic systems using nutrient solutions of different electrical conductivities. An experiment was set up following a randomized block design, in a 2 × 5 factorial scheme, with two hydroponic systems (NFT and Semi-hydroponic) and five levels of electrical conductivity (1.0, 2.0, 3.0, 4.0 and 5.0 dS m-1). The plants were harvested 35 days after transplanting and evaluated for the following variables: plant height, number of leaves, stem diameter, leaf area, shoot fresh and dry mass, leaf succulence, specific leaf area, petiole firmness, juice pH and soluble solids. Growth and quality variables were affected by the interaction between EC levels and hydroponic systems. The semi-hydroponic system promoted the greatest development of pak choi plants and greater tolerance to salinity. Plants cultivated in the NFT system had a lower nutritional requirement to reach maximum growth. Increase in nutrient solution EC did not affect the visual quality of pak choi, but reduced the physicochemical quality of its leaves.O pak choi é uma hortaliça folhosa rica bioativos importantes para a saúde humana. Por ser cultivado predominantemente nos continentes europeu e asiático, existem poucas informações sobre esta hortaliça na literatura brasileira. Objetivou-se avaliar a produção e a qualidade do pak choi cultivado em sistemas hidropônicos utilizando soluções nutritivas de diferentes valores de condutividade elétrica. Para isto, o experimento foi instalado seguindo o delineamento em blocos casualizados, em esquema fatorial 2 × 5, sendo dois sistemas hidropônicos (NFT e Semi-hidropônico) e cinco níveis de condutividade elétrica (1,0; 2,0; 3,0; 4,0 e 5,0 dS m-1). As plantas foram colhidas aos 35 dias após o transplantio e avaliadas quanto às seguintes variáveis: altura de planta, número de folhas, diâmetro do caule, área foliar, massa fresca e seca da parte aérea, suculência foliar, área foliar específica, firmeza do pecíolo, pH do suco e sólidos solúveis. As variáveis de crescimento e qualidade foram afetadas pela interação entre os fatores CEs e sistemas hidropônicos. O sistema semi-hidropônico proporcionou o maior desenvolvimento das plantas e maior tolerância à salinidade. As plantas cultivadas no sistema NFT apresentaram menor exigência nutricional para atingir o máximo crescimento. O aumento da CE da solução nutritiva não afetou a qualidade visual do pak choi, mas reduziu a qualidade físico-química das folhas
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Optimum Mode-Switching-Assisted Constant-Power Single- and Multicarrier Adaptive Modulation
No full textA set of optimum mode-switching levels is derived for a generic constant-power adaptive-modulation scheme based on a closed-form expression of the average bit error ratio (BER) and the average bits-per-symbol (BPS) throughput of the adaptive-modulation scheme. This results in a constant BER, variable-throughput arrangement. The corresponding BPS throughput performance and the achievable signal-to-noise ratio (SNR) gain are investigated for the optimum mode-switching assisted constant-power adaptive-modulation schemes employing various diversity schemes, including maximal ratio combining (MRC) receive-antenna diversity, a two-dimensional RAKE receiver, as well as transmit-diversity aided space-time (ST) coding, when communicating over various fading scenarios. The BPS throughput of our constant-power adaptive quadrature amplitude modulation (AQAM) scheme approaches the throughput of variable-power variable-rate AQAM within 1 dB. However, the achievable throughput gain of the adaptive-modulation scheme, in comparison to conventional fixed-mode modems, is substantially reduced as the diversity order of the receiver is increased. Hence, adaptive modulation constitutes a lower complexity alternative to multiple-transmitter and receiver-based systems when considering the range of techniques that can be used for mitigating the effects of the channel-quality fluctuations imposed by wireless channels. Index Terms—Adaptive modulation, adaptive quadrature amplitude modulation (AQAM), fading counter measures, Lagrangian optimization for adaptive modulation, optimum switching levels for adaptive modulation
"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States" By M. Carey.
No full text"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States: containing bried sketches of the moral and political character of those states.
By M. Carey, member of the American philosophical, and of the American Antiquarian Society, and author of The Olive Branch, Cindiciae Hibernicae, essays on banking, on political economy, and on internal improvement.
To which are now added the English editor's comments on the subject; together with Important Advice to Emigrants, and Cautions Against Impositions Practiced in the Outports
The Mx/G/1 queue with queue length dependent service times
No full textWe deal with the MX/G/1 queue where service times depend on the queue length at the service initiation. By using Markov renewal theory, we derive the queue length distribution at departure epochs. We also obtain the transient queue length distribution at time t and its limiting distribution and the virtual waiting time distribution. The numerical results for transient mean queue length and queue length distributions are given.Bong Dae Choi, Yeong Cheol Kim, Yang Woo Shin, and Charles E. M. Pearc
Author, publisher and bookseller : a tripartite synergy in Nigerian book industry
No full textThis work is about the roles of Author, Publisher and Bookseller in Book development in
Nigeria. The paper started by delving into the history of Book Publishing in Nigeria after
which it proceeded by defining who an author, a publisher, and a bookseller is and
expatiated on the indispensable roles of these key actors in Nigerian Book Industry and in
the emerging Information Society. Furthermore, the various constraints to book
development were identified while the paper advised on how the Book Industry can be
further promoted in Nigeria. However, the paper concluded and made recommendations
on how the Book sector can help in enhancing scholarship in the country
Andesipolis Whitfield & Choi, New
No full textAndesipolis Whitfield & Choi, New Genus Type species: Andesipolis masoni Choi & Suh, n. sp. (described below). Etymology: The generic name comes from the superficial resemblance to Rhysipolis, and from the Andean distribution of the genus. Diagnosis: Antennae 27–34 segmented, slightly longer than fore wing (Fig. 26). Malar suture present (Fig.18, 23). Ocelli in equilateral triangle, occipital carina complete, remaining separate from hypostomal carina to mandibular base (Fig. 12, 23). Maxillary palps 6 (sometimes appearing 7)segmented; labial palps 3 segmented. Pronope absent. Notauli short, covering only anterior part of mesonotum (Fig 6, 13, 14), shallow and narrowly elliptical midpit present (Fig 6, 13, 14). Epicnemial carina present (Fig. 5, 16, 20). Sternaulus present as a short groove on the posterior portion of mesopleuron (Fig. 5, 16, 20. Fore wing 2 a vein present (Fig. 1 3). Hind tibia without a fringe (comb) of spines on inner side of apex, or with a very poorly developed group of spines. Propodeum with (Figs. 7, 13, 21) or without (Fig. 15) welldefined areola, but when welldefined, usually elongate with a transverse carina dividing it into anterior and posterior portions. First tergite with distinct dorsope; dorsal carinae converging posteriorly (Fig. 7, 11, 15, 21). Ovipositor sheaths long and setose (Fig. 9, 17, 22). Distribution: Chile (Neotropical). Biology: Unknown. Comments: The new genus superficially resembles some species of Rhysipolis Förster in habitus (hence the name we have given it), and in addition in many details of the mesopleuron, wing venation and metasomal tergites. Unlike Rhysipolis, the forewing (Figs. 13) has a distinctly visible vein 2 a (not common within Braconidae yet found more basally within Hymenoptera). In addition the mesonotum has a longitudinal posterior groove as in many Hormiini and Rhyssalini (perhaps represented in an often less welldemarcated form in Pseudorhysipolis Scatilini, PenteadoDias and Achterberg), while the propodeum has a “double areola” pattern of carinae resembling especially Rhyssalini (figs. 7, 13, 21). The latter character has been proposed as likely to be plesiomorphic within Braconidae (Whitfield, 1988); some Rhysipolini also have a double areola, but of a different form (Spencer & Whitfield, 1999). Unlike typical Hormiini and Rhyssalini vein mcu meets RS + M before RS splits from M (in this respect resembling Rhysipolis, Exothecini and Rogadinae). Thus, the new genus Andesipolis has a unique combination of features that make it difficult to place to tribe or subfamily. This difficulty is largely due to the tribes and subfamilies not being very well defined in the first place. Its biology is unknown, but the typically long ovipositor (Figs. 9, 17, 22) resembles that of groups that attack hosts within shelters of leaf (Rhysipolis Shaw, 1983; Whitfield, 1992; Spencer & Whitfield, 1999) or stem tissue (Doryctine Marsh, 1997, or plant galls (Hydrangeocolini Oda et al., 2001; Belshaw et al., 2003). Andesipolis masoni Choi & Suh, n. sp. (Fig. 1, 4– 9) Female. Body length 2.6–2.9 mm; forewing length 3.5 mm. Head 1.1–1.2 X wider than mesoscutum. Face 1.6 X as broad at midheight as long medially, smooth and polished with scattered setae. Clypeus 2.6 X as broad as its height. Malar space 0.4 X eye height in frontal view. Eyes 1.2–1.3 X higher than width; eyes 1.6– 1.8 X longer than temple in lateral view. Vertex smooth and polished, with scattered setae. Occipital and hypostomal carinae remaining separate to mandibular base. Antennae slightly longer than forewing; 27–29 segmented. Maxillary and labial palps 6 and 3 segmented respectively. Mesosoma 1.8 1.9 X longer than high; 2.2–2.3 X longer than width between tegulae. Pronotum rugose dorsally; mostly polished laterally. Mesonotum weakly punctate with scattered setae; Notauli short, presenting only anterior onethird of mesonotum; midpit shallow and long, 0.4 0.6 X as long as mesonotum. Scutellum 1.2 X as long as width, smooth to weakly punctate and polished; scutellar sulcus 0.3 X as long as width. Propodeum with roughly pentagonal shape areola and distinct areolar crossbridge with irregular ridges arising inside of areola; median carina present; with irregular ridges around median carina and transverse carinae; polished anteriorlaterally. Hind coxa 2.0X as long as width, slightly shorter than first abdominal tergum, smooth and polished; hind tibial spur short, 0.24 X as long as basitarsus; hind tarsal claw simple. Wing Forewing: Stigma about 4.3 X longer than broad; vein r arising from middle of stigma; Vein r 0.5 X as long as vein 3 RSa. Vein 2 RS 0.8 X as long as vein 3 RSa. Vein 3 RSa 0.5 X as long as vein 3 RSb. Vein rm spectral, 0.6 X as long as vein 3 RSa. Vein 1 CUb 1.9 X as long as vein 1 CUa. Vein (RS+M)b present, short and spectral. Vein 1 1 AC 0.4 X as long as vein 2 1 A. Hindwing: Vein M+CU 1.9 X as long as vein 1 M. Vein cua 0.5 X as long as vein 1 M, slightly curved. Vein rm 0.6 X as long as vein 1 M. Metasoma Length of tergite I 0.8 X its apical width, distinctly sclerotized, reticulaterugose except granulate posteriordorsolateral portion; dorsal carinae converging but not jointed; dorsope rather large and deep. Tergite II and III smooth to granulate and polished, tergite II 1.9 X as long as tergite III. Hypopigium small. Ovipositor 0.8–0.9 X shorter than hind tibia, straight; ovipositor sheath 0.6 X shorter than ovipositor. Color Body generally orangebrown or brown; maxillary and labial palps pale yellow; antenna brown; mesosoma yellowish brown except brown scutellar sulcus; propodeum brown; legs orangebrown to brown. Male Unknown. Biology Unknown. Diagnosis This species can be distinguished from other Andesipolis species by the relatively short and straight ovipositor (the ovipositor is always shorter than the hind tibia). Material examined. Holotype. Female: Chile: Carelmapu, Llonquihue, 21–28.ii. 1957, L. E. Pena (CNC) Paratypes: 1 female, Chile: Pucotrihue, Valdivia, 11–13.iii. 1955, L. E. Pena (CNC); 1 female, Chepu, I. De Chiloé, 3.ii. 1952, Peña (CNC). Etymology. This species is named for the late W.R. M. Mason, who contributed a great deal to this work, as detailed above.Published as part of Whitfield, James B., Choi, Won-Young & Suh, Kyong-In, 2004, Andesipolis, a puzzling new genus of cyclostome Braconidae (Hymenoptera) from the Chilean Andes, with descriptions of three new species, pp. 1-15 in Zootaxa 438 on pages 3-5, DOI: 10.5281/zenodo.15724
Light Harvesting: Enhanced Light Harvesting in Mesoscopic Solar Cells by Multilevel Multiscale Patterned Photoelectrodes with Superpositioned Optical Properties (Adv. Funct. Mater. 36/2016)
No full textY.‐E. Sung, M. Choi, and co‐workers report photoelectrodes with multilevel multiscale structures, wherein nano‐ and micro‐scale patterns are integrated in z‐axis direction. Superposition of optical responses from constituent nano‐ and micro‐ architectures led to enhanced light harvesting in mesoscopic solar cells, which brought significantly enhanced photocurrent generation and energy conversion.N
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