644 research outputs found
ANALISIS NERACA AIR SUNGAI TENDEKI DI TITIK BENDUNG TENDEKI KOTA BITUNG
Bendung Tendeki memanfaatkan air dari Sungai Tendeki untuk dikelola menjadi air minum oleh PDAM. Berdasarkan hal tersebut, maka diperlukan studi mengenai analisis neraca air untuk melihat keseimbangan antara ketersediaan dan kebutuhan air di DAS Tendeki.Ketersediaan air DAS Tendeki dihitung menggunakan debit andalan dengan pencatatan data debit terukur selama 10 tahun yang selanjutnya menghitung debit andalan Q90% sebagai ketersediaan air dan Q95% sesuai Peraturan Pemerintah untuk pemeliharaan sungai. Kebutuhan air yang dihitung adalah kebutuhan pengambilan air IPA-SPAM PDAM dan kebutuhan pemeliharaan sungai atau Q95%. Analisis neraca air dilakukan dengan membandingkan ketersediaan air dengan kebutuhan air total di DAS Tendeki.Hasil analisis menunjukkan bahwa kebutuhan air minum dan kebutuhan pemeliharaan sungai Q95% tidak terpenuhi karena debit yang besar sehingga ketersediaan air tidak mencukupi. Ketersediaan air Q90% masih mencukupi untuk memenuhi kebutuhan air minum PDAM. Kata Kunci : Sungai Tendeki, DAS Tendeki, Debit Andalan, Neraca Ai
Perceived Attributes of Diffusion of Innovation Theory as a Theoretical Framework for understanding the Non-Use of Digital Library Services
Rogersâs diffusion of innovation theory is one theoretical approach to understand how members of a social system can adopt an innovation. Certain attributes of the innovation itself may facilitate its adoption. This paper highlights the necessity of designing a Digital Library Service (DLS) in conformity with the attributes of Innovation. These attributes are: relative advantage, compatibility, complexity, trialability and observability. It further discussed previous studies that have used the theory of perceived attribute of innovation to conduct research on acceptance and rejection of an innovation in different fields and concluded that Digital Library Service designers who adopts the theory of the perceived attributes of innovation will understand why there is low or non-use of these services and help them in designing DLS that can easily be adopted by potential users
Electrodynamic Radiation Reaction and General Relativity
We argue that the well-known problem of the instabilities associated with the
self-forces (radiation reaction forces) in classical electrodynamics are
possibly stabilized by the introduction of gravitational forces via general
relativity
Dynamics of Fermat potentials in non-perturbative gravitational lensing
We present a framework, based on the null-surface formulation of general
relativity, for discussing the dynamics of Fermat potentials for gravitational
lensing in a generic situation without approximations of any kind.
Additionally, we derive two lens equations: one for the case of thick compact
lenses and the other one for lensing by gravitational waves. These equations in
principle generalize the astrophysical scheme for lensing by removing the
thin-lens approximation while retaining the weak fields.Comment: Accepted for publication in Phys. Rev.
Fetal Environment and Schizophrenia
Schizophrenia and related disorders are adult-onset illnesses with no definitively established risk factors. Several studies report that exposures to infection and nutritional deprivation during early development may elevate the risk of later developing schizophrenia, specifically during the prenatal period. Preliminary evidence implicates lead exposure as well, suggesting that chemical exposures during early development may constitute a new class of risk factors for schizophrenia that has not been adequately investigated. Exposure to lead is given as an example of a chemical agent for which some effects have been described throughout the life course on both general neurodevelopmental outcomes and now on a specific psychiatric diagnosis. Findings from prospectively collected birth cohorts are offered as examples of both innovations in methodology and opportunities for future generations of investigators
Phase-Space Metric for Non-Hamiltonian Systems
We consider an invariant skew-symmetric phase-space metric for
non-Hamiltonian systems. We say that the metric is an invariant if the metric
tensor field is an integral of motion. We derive the time-dependent
skew-symmetric phase-space metric that satisfies the Jacobi identity. The
example of non-Hamiltonian systems with linear friction term is considered.Comment: 12 page
Videographic Analysis of Blink Dynamics following Upper Eyelid Blepharoplasty and Its Association with Dry Eye
Background: This study was undertaken to characterize the effects of upper eyelid
blepharoplasty on blink dynamics and to evaluate the hypothesis that changes in
blink dynamics following blepharoplasty are associated with postoperative dry eye. //
Methods: The voluntary blink of 14 eyes of 7 patients with dermatochalasis undergoing upper eyelid blepharoplasty was recorded with a high-speed camera preoperatively and 6â8 months postoperatively, alongside a group of 11 controls. The
images were analyzed for palpebral aperture, blink duration, and maximum velocity during opening and closing phases. Patients undergoing blepharoplasty were
assessed for dry eye symptoms pre- and postoperatively at 6â8 months using the
ocular surface disease index score. //
Results: Despite intraoperative orbicularis oculi resection, there was no significant
compromise of blink duration or maximum velocity of eyelid opening or closure
post-blepharoplasty. Postoperatively, patients had an increase in palpebral aperture
compared with both preoperatively (8.71 versus 7.85mm; P = 0.013) and control
groups (8.71 versus 7.87mm; P = 0.04). Postoperatively at 6â8 months, there was
an increase in dry eye symptoms in 6 of 7 patients compared with preoperatively
(ocular surface disease index, 16.6 versus 12.5; P < 0.05). There was no positive
correlation between the increase in palpebral aperture and the increase in dry eye
symptoms (r = â0.4; P = 0.30). //
Conclusions: Using modern videographic technology, this study demonstrates that
upper eyelid blepharoplasty results in an increase in resting palpebral aperture but
has no effect on dynamic blink parameters. Changes in palpebral aperture or blink
dynamics are unlikely to be the cause of dry eye syndrome following blepharoplasty
Image distortion in non perturbative gravitational lensing
We introduce the idea of {\it shape parameters} to describe the shape of the
pencil of rays connecting an observer with a source lying on his past
lightcone. On the basis of these shape parameters, we discuss a setting of
image distortion in a generic (exact) spacetime, in the form of three {\it
distortion parameters}. The fundamental tool in our discussion is the use of
geodesic deviation fields along a null geodesic to study how source shapes are
propagated and distorted on the path to an observer. We illustrate this
non-perturbative treatment of image distortion in the case of lensing by a
Schwarzschild black hole. We conclude by showing that there is a
non-perturbative generalization of the use of Fermat's principle in lensing in
the thin-lens approximation.Comment: 22 pages, 6 figures, to appear in Phys. Rev. D (January 2001
Semiclassical calculation of the vibrational echo
The infrared echo measurement probes the time scales of the molecular motions that couple to a vibrational transition. Computation of the echo observable within rigorous quantum mechanics is problematic for systems with many degrees of freedom, motivating the development of semiclassical approximations to the nonlinear optical response. We present a semiclassical approximation to the echo observable, based on the Herman-Kluk propagator. This calculation requires averaging over a quantity generated by two pairs of classical trajectories and associated stability matrices, connected by a pair of phase-space jumps. Quantum, classical, and semiclassical echo calculations are compared for a thermal ensemble of noninteracting anharmonic oscillators. The semiclassical approach uses input from classical mechanics to reproduce the significant features of a complete, quantum mechanical calculation of the nonlinear response
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