12,618 research outputs found
Analisis Faktor-faktor yang Mempengaruhi Perilaku Konsumen dalam Mengkonsumsi Daging Ayam Kampung di Kota Medan (Studi Kasus: Pasar Sambas, Medan)
Tujuan dari penelitian ini adalah untuk mengetahui perkembangan permintaan konsumen terhadap daging ayam kampung dan harga ayam kampung; untuk mengetahui perilaku konsumen terhadap konsumsi daging ayam kampung di Kota Medan dan untuk menganalisis faktor-faktor yang mempengaruhi konsumsi daging ayam kampung di Pasar Sambas, Kota Medan. Metode analisis yang digunakan dalam penelitian ini adalah metode analisis regresi linier berganda menggunakan alat bantu SPSS 16. Penentuan daerah penelitian dilakukan secara purposive. Teknik pengambilan sampel dengan metode accidental sampling dengan jumlah sampel 30 konsumen. Penelitian ini dilakukan pada bulan Mei sampai Juli tahun 2013. Hasil penelitian menunjukkan bahwa dari hasil estimasi dapat diperoleh nilai determinasi (R2) sebesar 0,707. Hal ini berarti 70,7% variasi yang terjadi pada variabel umur, tingkat pendidikan, jumlah tanggungan, pendapatan dan harga daging ayam kampung dapat menjelaskan jumlah konsumsi daging ayam kampung, sedangkan 29,3% lagi dipengaruhi oleh variabel lain. Secara serempak menunjukkan bahwa dari keseluruhan variabel bebas memberikan pengaruh yang nyata terhadap jumlah konsumsi daging ayam kampung. Secara parsial variabel jumlah tanggungan dan pendapatan berpengaruh nyata terhadap jumlah konsumsi daging ayam kampung, sedangkan pada umur, tingkat pendidikan dan harga daging ayam kampung tidak berpengaruh nyata terhadap jumlah konsumsi daging ayam kampung
Optimal leverage from non-ergodicity
In modern portfolio theory, the balancing of expected returns on investments
against uncertainties in those returns is aided by the use of utility
functions. The Kelly criterion offers another approach, rooted in information
theory, that always implies logarithmic utility. The two approaches seem
incompatible, too loosely or too tightly constraining investors' risk
preferences, from their respective perspectives. The conflict can be understood
on the basis that the multiplicative models used in both approaches are
non-ergodic which leads to ensemble-average returns differing from time-average
returns in single realizations. The classic treatments, from the very beginning
of probability theory, use ensemble-averages, whereas the Kelly-result is
obtained by considering time-averages. Maximizing the time-average growth rates
for an investment defines an optimal leverage, whereas growth rates derived
from ensemble-average returns depend linearly on leverage. The latter measure
can thus incentivize investors to maximize leverage, which is detrimental to
time-average growth and overall market stability. The Sharpe ratio is
insensitive to leverage. Its relation to optimal leverage is discussed. A
better understanding of the significance of time-irreversibility and
non-ergodicity and the resulting bounds on leverage may help policy makers in
reshaping financial risk controls.Comment: 17 pages, 3 figures. Updated figures and extended discussion of
ergodicit
Retaining Expression on De-identified Faces
© Springer International Publishing AG 2017The extensive use of video surveillance along with advances in face recognition has ignited concerns about the privacy of the people identifiable in the recorded documents. A face de-identification algorithm, named k-Same, has been proposed by prior research and guarantees to thwart face recognition software. However, like many previous attempts in face de-identification, kSame fails to preserve the utility such as gender and expression of the original data. To overcome this, a new algorithm is proposed here to preserve data utility as well as protect privacy. In terms of utility preservation, this new algorithm is capable of preserving not only the category of the facial expression (e.g., happy or sad) but also the intensity of the expression. This new algorithm for face de-identification possesses a great potential especially with real-world images and videos as each facial expression in real life is a continuous motion consisting of images of the same expression with various degrees of intensity.Peer reviewe
A Global SU(5) F-theory model with Wilson line breaking
We engineer compact SU(5) Grand Unified Theories in F-theory in which
GUT-breaking is achieved by a discrete Wilson line. Because the internal gauge
field is flat, these models avoid the high scale threshold corrections
associated with hypercharge flux. Along the way, we exemplify the
`local-to-global' approach in F-theory model building and demonstrate how the
Tate divisor formalism can be used to address several challenges of extending
local models to global ones. These include in particular the construction of
G-fluxes that extend non-inherited bundles and the engineering of U(1)
symmetries. We go beyond chirality computations and determine the precise
(charged) massless spectrum, finding exactly three families of quarks and
leptons but excessive doublet and/or triplet pairs in the Higgs sector
(depending on the example) and vector-like exotics descending from the adjoint
of SU(5)_{GUT}. Understanding why vector-like pairs persist in the Higgs sector
without an obvious symmetry to protect them may shed light on new solutions to
the mu problem in F-theory GUTs.Comment: 95 pages (71 pages + 1 Appendix); v2 references added, minor
correction
Quantum to Classical Transition in a Single-Ion Laser
Stimulated emission of photons from a large number of atoms into the mode of
a strong light field is the principle mechanism for lasing in "classical"
lasers. The onset of lasing is marked by a threshold which can be characterised
by a sharp increase in photon flux as a function of external pumping strength.
The same is not necessarily true for the fundamental building block of a laser:
a single trapped atom interacting with a single optical radiation mode. It has
been shown that such a "quantum" laser can exhibit thresholdless lasing in the
regime of strong coupling between atom and radiation field. However, although
theoretically predicted, a threshold at the single-atom level could not be
experimentally observed so far. Here, we demonstrate and characterise a
single-atom laser with and without threshold behaviour by changing the strength
of atom-light field coupling. We observe the establishment of a laser threshold
through the accumulation of photons in the optical mode even for a mean photon
number substantially lower than for the classical case. Furthermore,
self-quenching occurs for very strong external pumping and constitutes an
intrinsic limitation of single-atom lasers. Moreover, we find that the
statistical properties of the emitted light can be adjusted for weak external
pumping, from the quantum to the classical domain. Our observations mark an
important step towards fundamental understanding of laser operation in the
few-atom limit including systems based on semiconductor quantum dots or
molecules.Comment: 19 pages, 4 figures, 10 pages supplement, accepted by Nature Physic
A cardinal role for cathepsin D in co-ordinating the host-mediated apoptosis of macrophages and killing of pneumococci
The bactericidal function of macrophages against pneumococci is enhanced by their apoptotic demise, which is controlled by the anti-apoptotic protein Mcl-1. Here, we show that lysosomal membrane permeabilization (LMP) and cytosolic translocation of activated cathepsin D occur prior to activation of a mitochondrial pathway of macrophage apoptosis. Pharmacological inhibition or knockout of cathepsin D during pneumococcal infection blocked macrophage apoptosis. As a result of cathepsin D activation, Mcl-1 interacted with its ubiquitin ligase Mule and expression declined. Inhibition of cathepsin D had no effect on early bacterial killing but inhibited the late phase of apoptosis-associated killing of pneumococci in vitro. Mice bearing a cathepsin D-/- hematopoietic system demonstrated reduced macrophage apoptosis in vivo, with decreased clearance of pneumococci and enhanced recruitment of neutrophils to control pulmonary infection. These findings establish an unexpected role for a cathepsin D-mediated lysosomal pathway of apoptosis in pulmonary host defense and underscore the importance of apoptosis-associated microbial killing to macrophage function
Floral temperature and optimal foraging: is heat a feasible floral reward for pollinators?
As well as nutritional rewards, some plants also reward ectothermic pollinators with warmth. Bumble bees have some control over their temperature, but have been shown to forage at warmer flowers when given a choice, suggesting that there is some advantage to them of foraging at warm flowers (such as reducing the energy required to raise their body to flight temperature before leaving the flower). We describe a model that considers how a heat reward affects the foraging behaviour in a thermogenic central-place forager (such as a bumble bee). We show that although the pollinator should spend a longer time on individual flowers if they are warm, the increase in total visit time is likely to be small. The pollinator's net rate of energy gain will be increased by landing on warmer flowers. Therefore, if a plant provides a heat reward, it could reduce the amount of nectar it produces, whilst still providing its pollinator with the same net rate of gain. We suggest how heat rewards may link with plant life history strategies
Infectious Disease Ontology
Technological developments have resulted in tremendous increases in the volume and diversity of the data and information that must be processed in the course of biomedical and clinical research and practice. Researchers are at the same time under ever greater pressure to share data and to take steps to ensure that data resources are interoperable. The use of ontologies to annotate data has proven successful in supporting these goals and in providing new possibilities for the automated processing of data and information. In this chapter, we describe different types of vocabulary resources and emphasize those features of formal ontologies that make them most useful for computational applications. We describe current uses of ontologies and discuss future goals for ontology-based computing, focusing on its use in the field of infectious diseases. We review the largest and most widely used vocabulary resources relevant to the study of infectious diseases and conclude with a description of the Infectious Disease Ontology (IDO) suite of interoperable ontology modules that together cover the entire infectious disease domain
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