1,341 research outputs found
Evaluasi Penyimpangan Pondasi Tiang Dari Rencana Awal
Penelitian ini bertujuan untuk mencari ketepatan dalam pemancangan pondasi tiang dan membandingkan penyimpangan titik tiang pancang yang terjadi di lapangan dengan batasan standar-standar yang ada. Standar-standar yang digunakan untuk batasan toleransi penyimpangan pada tiang pancang adalah British Standard, Canadian Standard, dan Indian Standard. Ke-3 standar di atas menggunakan batas penyimpangan tiang pancang maksimum sebesar 75mm dan 150mm. Data yang menunjukan besarnya penyimpangan tiang pancang ditentukan dari hasil perpindahan tiang secara lateral dari posisi awal rencana tiang pancang tersebut. Hasil penelitian awal terhadap 19 proyek yang menggunakan pondasi tiang dengan dimensi dari 250mm sampai 600mm menunjukan bahwa sekitar 40% tiang dengan diameter 600mm berada dalam batas penyimpangan kurang dari 75mm, sedangkan sekitar 60% tiang dengan diameter 500mm, dan sekitar 65% tiang berdiameter 250mm sampai dengan 450mm. Dengan kata lain dapat disimpulkan bahwa semakin besar dimensi tiang semakin menurun tingkat ketepatan posisi tiang
VALIDATION OF TROPICAL RAINFALL MEASURING MISSION (TRMM) RAINFALL DATA FOR THE KAPUAS HULU DISTRICT AREA
Rainfall is a critical element in the hydrological cycle. Therefore, accurate rainfall inputs are essential for reliable hydrological predictions in various water resource analyses. Many areas in the tropics depend on rainfall for multiple needs because rainfall has an essential influence on numerous aspects of human life, especially in water resources planning and management. However, not all areas have rainfall recording stations using manual rain and gauges or automatic rainfall recorders, so rainfall records are rarely complete; this is also the case in Kapuas Hulu District, West Kalimantan Province.This research article presents the results of TRMM satellite rainfall data research in Kapuas Hulu District, with validated rainfall data, 1-day maximum rainfall data, and rainfall amount data. Validation stages are carried out by calibrating, verifying, and correcting rainfall data. As a comparison station (dependent variable) is the BMKG Pangsuma observation station, KPH-06 Nanga Kantuk, KPH-08 Ng. Silat, KPH-09 Jongkong, KPH-13 Tepuai in 1998-2019.The results of the analysis show that the best correlation value on the amount of rainfall data and 1-day maximum rainfall data obtained from Grid 30 TRMM of 0.83 and 0.82 with the observation station is BMKG Pangsuma Station, and then the equation obtained from the analysis results on the grid is used as an equation for correction. The data correction equation for the amount of rainfall is Y = 1.1578 X - 98.5547, and the 1-day maximum rainfall data correction equation is Y = 1.2036 X - 28.4197
Electromagnetic Form Factors of the Nucleon and Compton Scattering
We review the experimental and theoretical status of elastic electron
scattering and elastic low-energy photon scattering (with both real and virtual
photons) from the nucleon. As a consequence of new experimental facilities and
new theoretical insights, these subjects are advancing with unprecedented
precision. These reactions provide many important insights into the spatial
distributions and correlations of quarks in the nucleon.Comment: 47 pages, 18 figures, includes corrections and updates to published
manuscrip
Pollutant dispersion in a developing valley cold-air pool
Pollutants are trapped and accumulate within cold-air pools, thereby affecting air quality. A numerical model is used to quantify the role of cold-air-pooling processes in the dispersion of air pollution in a developing cold-air pool within an alpine valley under decoupled stable conditions. Results indicate that the negatively buoyant downslope flows transport and mix pollutants into the valley to depths that depend on the temperature deficit of the flow and the ambient temperature structure inside the valley. Along the slopes, pollutants are generally entrained above the cold-air pool and detrained within the cold-air pool, largely above the ground-based inversion layer. The ability of the cold-air pool to dilute pollutants is quantified. The analysis shows that the downslope flows fill the valley with air from above, which is then largely trapped within the cold-air pool, and that dilution depends on where the pollutants are emitted with respect to the positions of the top of the ground-based inversion layer and cold-air pool, and on the slope wind speeds. Over the lower part of the slopes, the cold-air-pool-averaged concentrations are proportional to the slope wind speeds where the pollutants are emitted, and diminish as the cold-air pool deepens. Pollutants emitted within the ground-based inversion layer are largely trapped there. Pollutants emitted farther up the slopes detrain within the cold-air pool above the ground-based inversion layer, although some fraction, increasing with distance from the top of the slopes, penetrates into the ground-based inversion layer.Peer reviewe
Spatial Bloom Filters: Enabling Privacy in Location-Aware Applications
The wide availability of inexpensive positioning systems made it possible to embed them into smartphones and other personal devices. This marked the beginning of location-aware applications, where users request personalized services based on their geographic position. The location of a user is, however, highly sensitive information: the user's privacy can be preserved if only the minimum amount of information needed to provide the service is disclosed at any time. While some applications, such as navigation systems, are based on the users' movements and therefore require constant tracking, others only require knowledge of the user's position in relation to a set of points or areas of interest. In this paper we focus on the latter kind of services, where location information is essentially used to determine membership in one or more geographic sets. We address this problem using Bloom Filters (BF), a compact data structure for representing sets. In particular, we present an extension of the original Bloom filter idea: the Spatial Bloom Filter (SBF). SBF's are designed to manage spatial and geographical information in a space efficient way, and are well-suited for enabling privacy in location-aware applications. We show this by providing two multi-party protocols for privacy-preserving computation of location information, based on the known homomorphic properties of public key encryption schemes. The protocols keep the user's exact position private, but allow the provider of the service to learn when the user is close to specific points of interest, or inside predefined areas. At the same time, the points and areas of interest remain oblivious to the user
DHODH modulates transcriptional elongation in the neural crest and melanoma
Melanoma is a tumour of transformed melanocytes, which are originally derived from the embryonic neural crest. It is unknown to what extent the programs that regulate neural crest development interact with mutations in the BRAF oncogene, which is the most commonly mutated gene in human melanoma1. We have used zebrafish embryos to identify the initiating transcriptional events that occur on activation of human BRAF(V600E) (which encodes an amino acid substitution mutant of BRAF) in the neural crest lineage. Zebrafish embryos that are transgenic for mitfa:BRAF(V600E) and lack p53 (also known as tp53) have a gene signature that is enriched for markers of multipotent neural crest cells, and neural crest progenitors from these embryos fail to terminally differentiate. To determine whether these early transcriptional events are important for melanoma pathogenesis, we performed a chemical genetic screen to identify small-molecule suppressors of the neural crest lineage, which were then tested for their effects on melanoma. One class of compound, inhibitors of dihydroorotate dehydrogenase (DHODH), for example leflunomide, led to an almost complete abrogation of neural crest development in zebrafish and to a reduction in the self-renewal of mammalian neural crest stem cells. Leflunomide exerts these effects by inhibiting the transcriptional elongation of genes that are required for neural crest development and melanoma growth. When used alone or in combination with a specific inhibitor of the BRAF(V600E) oncogene, DHODH inhibition led to a marked decrease in melanoma growth both in vitro and in mouse xenograft studies. Taken together, these studies highlight developmental pathways in neural crest cells that have a direct bearing on melanoma formation
Prospective, randomized evaluation of a personal digital assistant-based research tool in the emergency department
Background
Personal digital assistants (PDA) offer putative advantages over paper for collecting research data. However, there are no data prospectively comparing PDA and paper in the emergency department. The aim of this study was to prospectively compare the performance of PDA and paper enrollment instruments with respect to time required and errors generated.
Methods
We randomized consecutive patients enrolled in an ongoing prospective study to having their data recorded either on a PDA or a paper data collection instrument. For each method, we recorded the total time required for enrollment, and the time required for manual transcription (paper) onto a computer database. We compared data error rates by examining missing data, nonsensical data, and errors made during the transcription of paper forms. Statistical comparisons were performed by Kruskal-Wallis and Poisson regression analyses for time and errors, respectively.
Results
We enrolled 68 patients (37 PDA, 31 paper). Two of 31 paper forms were not available for analysis. Total data gathering times, inclusive of transcription, were significantly less for PDA (6:13 min per patient) compared to paper (9:12 min per patient; p < 0.001). There were a total of 0.9 missing and nonsense errors per paper form compared to 0.2 errors per PDA form (p < 0.001). An additional 0.7 errors per paper form were generated during transcription. In total, there were 1.6 errors per paper form and 0.2 errors per PDA form (p < 0.001).
Conclusion
Using a PDA-based data collection instrument for clinical research reduces the time required for data gathering and significantly improves data integrity
Fractional quantum Hall effect in a quantum point contact at filling fraction 5/2
Recent theories suggest that the excitations of certain quantum Hall states
may have exotic braiding statistics which could be used to build topological
quantum gates. This has prompted an experimental push to study such states
using confined geometries where the statistics can be tested. We study the
transport properties of quantum point contacts (QPCs) fabricated on a
GaAs/AlGaAs two dimensional electron gas that exhibits well-developed
fractional quantum Hall effect, including at bulk filling fraction 5/2. We find
that a plateau at effective QPC filling factor 5/2 is identifiable in point
contacts with lithographic widths of 1.2 microns and 0.8 microns, but not 0.5
microns. We study the temperature and dc-current-bias dependence of the 5/2
plateau in the QPC, as well as neighboring fractional and integer plateaus in
the QPC while keeping the bulk at filling factor 3. Transport near QPC filling
factor 5/2 is consistent with a picture of chiral Luttinger liquid edge-states
with inter-edge tunneling, suggesting that an incompressible state at 5/2 forms
in this confined geometry
The Impact of HAART on the Respiratory Complications of HIV Infection: Longitudinal Trends in the MACS and WIHS Cohorts
Objective: To review the incidence of respiratory conditions and their effect on mortality in HIV-infected and uninfected individuals prior to and during the era of highly active antiretroviral therapy (HAART). Design: Two large observational cohorts of HIV-infected and HIV-uninfected men (Multicenter AIDS Cohort Study [MACS]) and women (Women's Interagency HIV Study [WIHS]), followed since 1984 and 1994, respectively. Methods: Adjusted odds or hazards ratios for incident respiratory infections or non-infectious respiratory diagnoses, respectively, in HIV-infected compared to HIV-uninfected individuals in both the pre-HAART (MACS only) and HAART eras; and adjusted Cox proportional hazard ratios for mortality in HIV-infected persons with lung disease during the HAART era. Results: Compared to HIV-uninfected participants, HIV-infected individuals had more incident respiratory infections both pre-HAART (MACS, odds ratio [adjusted-OR], 2.4; 95% confidence interval [CI], 2.2-2.7; p<0.001) and after HAART availability (MACS, adjusted-OR, 1.5; 95%CI 1.3-1.7; p<0.001; WIHS adjusted-OR, 2.2; 95%CI 1.8-2.7; p<0.001). Chronic obstructive pulmonary disease was more common in MACS HIV-infected vs. HIV-uninfected participants pre-HAART (hazard ratio [adjusted-HR] 2.9; 95%CI, 1.02-8.4; p = 0.046). After HAART availability, non-infectious lung diseases were not significantly more common in HIV-infected participants in either MACS or WIHS participants. HIV-infected participants in the HAART era with respiratory infections had an increased risk of death compared to those without infections (MACS adjusted-HR, 1.5; 95%CI, 1.3-1.7; p<0.001; WIHS adjusted-HR, 1.9; 95%CI, 1.5-2.4; p<0.001). Conclusion: HIV infection remained a significant risk for infectious respiratory diseases after the introduction of HAART, and infectious respiratory diseases were associated with an increased risk of mortality. © 2013 Gingo et al
- …