1,794 research outputs found

    Analisis Cfd Hambatan Lambung Kapal Trimaran Asimetris Flat Side Inside Dengan Variasi Jarak Antar Lambung Secara Membujur

    Full text link
    Kapal dibuat dengan fungsi sebagai sarana transportasi untuk kebutuhan niaga maupun perang. Saat ini kebutuhan kapal cepat meningkat sehingga diperlukan kapal dengan bentuk multihull, salah satunya adalah kapal Trimaran. Kapal Trimaran merupakan kapal yang mempunyai 3 lambung, yaitu satu mainhull dan dua side-hull atau disebut juga outriggers sehingga mempunyai nilai stabilitas yang tinggi. Untuk itu, perlu dilakukan penelitian lebih lanjut untuk membuat kapal Trimaran yang memiliki hambatan yang kecil sehingga dapat menambah nilai ekonomis dari segi efisiensi mesin dan performa kapal yang baik. Berbagai bentuk badan kapal kemudian dikembangkan untuk mendapatkan desain lambung kapal Trimaran yang paling optimum salah satunya adalah kapal Trimaran flat side inside, yaitu sebuah konfigurasi baru dengan lambung yang memiliki bidang datar atau asimetris di dalam. Penelitian ini bertujuan untuk mendapatkan variasi letak stagger atau jarak antar lambung secara membujur (R/L) kapal Trimaran asimetris flat side inside yang menghasilkan hambatan paling kecil dengan menggunakan bantuan software Computational Fluid Dynamics (CFD). Dengan melakukan variasi kecepatan yaitu 12, 14, 16, dan 22 knot dan variasi jarak antar lambung (R/L) dimana R merupakan jarak antar lambung secara membujur dan L adalah panjang kapal mainhull, yaitu untuk R/L = 0.1, R/L = 0.2 dan R/L = 0.3 pada ketentuan jarak antar lambung secara melintang (S/L) = 0.4 dapat dilihat pengaruh interaksi gelombang terhadap nilai hambatan gelombang kapal Trimaran asimetris flat side inside. Hasil pengujian didapatkan bahwa model C dengan R/L = 0,3 dan S/L = 0,4 adalah variasi model paling baik dalam tugas akhir ini karena menghasilkan hambatan viscous dan hambatan total terkecil dengan presentase yang dibandingkan dengan model awal masing-masing 7,137 % dan 24,965 %

    The Abandoned Ocean: A History of United States Maritime Policy

    Get PDF

    Does Caffeine Influence Salivary IgA Responses In A Dose-Dependent Manner Following High-Intensity Treadmill Exercise?

    Get PDF
    Introduction: Caffeine ingestion is associated with enhanced athletic performance, with doses as low as 2 mg.kg-1 body mass (BM) proving ergogenic. Bishop et al. (2006) have shown that ingesting a 6 mg.kg-1 BM dose of caffeine 1 h prior to 90 min of cycle exercise at 70%causes a transient increase in saliva Immunoglobulin A (IgA) concentration both during and immediately following exercise. However, no research has identified if the same response occurs with either lower or higher doses of caffeine. As such the purpose of this study was to examine the dose-response effects of caffeine ingestion on salivary IgA responses following high-intensity running. Methods: In a double blind randomised crossover design, 12 endurance trained male runners (age: 29 ± 3, 62.7 ± 5.1 mL·kg·min-1, mean ± SD) ran for 70 min at 80% 60 min after ingesting 0 (PLA), 2 (2CAF), 4 (4CAF), 6 (6CAF) or 8 (8CAF) mg·kg-1 BM of caffeine. For PLA, 6 mg·kg-1 BM of cornflour was ingested. Unstimulated whole saliva samples were obtained before supplementation, pre-exercise, after 35 min of exercise, immediately post-exercise and 1 h post-exercise. Saliva IgA was determined using ELISA, while caffeine concentrations were determined via HPLC. Results: Saliva caffeine concentrations were significantly increased at all time points (pre-, mid-, post- and 1 h post-exercise) when compared to pre-supplement in a dose-dependent manner (P\u3c0.001; peak concentration: PLA: 0 ± 0; 2CAF: 10 ± 3; 4CAF: 22 ± 8; 6CAF: 40 ± 9; 8CAF: 44 ± 9 μM). However, there was no dose-response effect of caffeine on either saliva IgA concentration or secretion rate before, during or after exercise. In fact neither caffeine nor exercise affected saliva IgA secretion rate or concentration. Conclusion: These findings suggest that caffeine ingestion (from 2-8 mg.kg-1 BM) 60 min prior to prolonged high-intensity treadmill running has no effect on saliva IgA responses following exercise. As such it can be suggested that athletes wanting to consume caffeine for ergogenic purposes can potentially do so (up to a dose of 8 mg.kg-1 BM) without reducing mucosal immunity

    Dissociation of Action and Object Naming: Evidence From Cortical Stimulation Mapping

    Get PDF
    This cortical stimulation mapping study investigates the neural representation of action and object naming. Data from 13 neurosurgical subjects undergoing awake cortical mapping is presented. Our findings indicate clear evidence of differential disruption of noun and verb naming in the context of this naming task. At the individual level, evidence was found for punctuate regions of perisylvian cortex subserving noun and verb function. Across subjects, however, the location of these sites varied. This finding may help explain discrepancies between lesion and functional imaging studies of noun and verb naming. In addition, an alternative coding of these data served to highlight the grammatical class vulnerability of the target response. The use of this coding scheme implicates a role for the supramarginal gyrus in verb-naming behavior. These data are discussed with respect to a functional-anatomical pathway underlying verb naming

    The Polonnaruwa meteorite: oxygen isotope, crystalline and biological composition

    Full text link
    Results of X-Ray Diffraction (XRD) analysis, Triple Oxygen Isotope analysis and Scanning Electron Microscopic (SEM) studies are presented for stone fragments recovered from the North Central Province of Sri Lanka following a witnessed fireball event on 29 December 2012. The existence of numerous nitrogen depleted highly carbonaceous fossilized biological structures fused into the rock matrix is inconsistent with recent terrestrial contamination. Oxygen isotope results compare well with those of CI and CI-like chondrites but are inconsistent with the fulgurite hypothesis.Comment: 7 pages, 7 figures, 4 table

    Ultraviolet Imaging Polarimetry of the Large Magellanic Cloud. II. Models

    Get PDF
    Motivated by new sounding-rocket wide-field polarimetric images of the Large Magellanic Cloud, we have used a three-dimensional Monte Carlo radiation transfer code to investigate the escape of near-ultraviolet photons from young stellar associations embedded within a disk of dusty material (i.e. a galaxy). As photons propagate through the disk, they may be scattered or absorbed by dust. Scattered photons are polarized and tracked until they escape to be observed; absorbed photons heat the dust, which radiates isotropically in the far-infrared, where the galaxy is optically thin. The code produces four output images: near- UV and far-IR flux, and near-UV images in the linear Stokes parameters Q and U. From these images we construct simulated UV polarization maps of the LMC. We use these maps to place constraints on the star + dust geometry of the LMC and the optical properties of its dust grains. By tuning the model input parameters to produce maps that match the observed polarization maps, we derive information about the inclination of the LMC disk to the plane of the sky, and about the scattering phase function g. We compute a grid of models with i = 28 deg., 36 deg., and 45 deg., and g = 0.64, 0.70, 0.77, 0.83, and 0.90. The model which best reproduces the observed polarization maps has i = 36 +2/-5 degrees and g ~0.7. Because of the low signal-to-noise in the data, we cannot place firm constraints on the value of g. The highly inclined models do not match the observed centro-symmetric polarization patterns around bright OB associations, or the distribution of polarization values. Our models approximately reproduce the observed ultraviolet photopolarimetry of the western side of the LMC; however, the output images depend on many input parameters and are nonunique.Comment: Accepted to AJ. 20 pages, 7 figure

    Communication of bed allocation decisions in a critical care unit and accountability for reasonableness

    Get PDF
    BACKGROUND: Communication may affect perceptions of fair process for intensive care unit bed allocation decisions through its impact on the publicity condition of accountability for reasonableness. METHODS: We performed a qualitative case study to describe participant perceptions of the communication of bed allocation decisions in an 18-bed university affiliated, medical-surgical critical care unit at Sunnybrook and Women's College Health Sciences Centre. Interviewed participants were 3 critical care physicians, 4 clinical fellows in critical care, 4 resource nurses, 4 "end-users" (physicians who commonly referred patients to the unit), and 3 members of the administrative staff. Median bed occupancy during the study period (Jan-April 2003) was 18/18; daily admissions and discharges (median) were 3. We evaluated our description using the ethical framework "accountability for reasonableness" (A4R) to identify opportunities for improvement. RESULTS: The critical care physician, resource nurse, critical care fellow and end-users (trauma team leader, surgeons, neurosurgeons, anesthesiologists) functioned independently in unofficial "parallel tracks" of bed allocation decision-making; this conflicted with the official designation of the critical care physician as the sole authority. Communication between key decision-makers was indirect and could exclude those affected by the decisions; notably, family members. Participants perceived a lack of publicity for bed allocation rationales. CONCLUSION: The publicity condition should be improved for critical care bed allocation decisions. Decision-making in the "parallel tracks" we describe might be unavoidable within usual constraints of time, urgency and demand. Formal guidelines for direct communication between key participants in such circumstances would help to improve the fairness of these decisions

    Comparative effectiveness of sodium-glucose cotransporter 2 inhibitors vs sulfonylureas in patients with type 2 diabetes

    Get PDF
    IMPORTANCE: In the treatment of type 2 diabetes, evidence of the comparative effectiveness of sodium-glucose cotransporter 2 (SGLT2) inhibitors vs sulfonylureas-the second most widely used antihyperglycemic class after metformin-is lacking. OBJECTIVE: To evaluate the comparative effectiveness of SGLT2 inhibitors and sulfonylureas associated with the risk of all-cause mortality among patients with type 2 diabetes using metformin. DESIGN, SETTING, AND PARTICIPANTS: A cohort study used data from the US Department of Veterans Affairs compared the use of SGLT2 inhibitors vs sulfonylureas in individuals receiving metformin for treatment of type 2 diabetes. A total of 23 870 individuals with new use of SGLT2 inhibitors and 104 423 individuals with new use of sulfonylureas were enrolled between October 1, 2016, and February 29, 2020, and followed up until January 31, 2021. EXPOSURES: New use of SGLT2 inhibitors or sulfonylureas. MAIN OUTCOMES AND MEASURES: This study examined the outcome of all-cause mortality. Predefined variables and covariates identified by a high-dimensional variable selection algorithm were used to build propensity scores. The overlap weighting method based on the propensity scores was used to estimate the intention-to-treat effect sizes of SGLT2 inhibitor compared with sulfonylurea therapy. The inverse probability of the treatment adherence weighting method was used to estimate the per-protocol effect sizes. RESULTS: Among the 128 293 participants (mean [SD] age, 64.60 [9.84] years; 122 096 [95.17%] men), 23 870 received an SGLT2 inhibitor and 104 423 received a sulfonylurea. Compared with sulfonylureas, SGLT2 inhibitors were associated with reduced risk of all-cause mortality (hazard ratio [HR], 0.81; 95% CI, 0.75-0.87), yielding an event rate difference of -5.15 (95% CI, -7.16 to -3.02) deaths per 1000 person-years. Compared with sulfonylureas, SGLT2 inhibitors were associated with a reduced risk of death, regardless of cardiovascular disease status, in several categories of estimated glomerular filtration rate (including rates from \u3e90 to ≤30 mL/min/1.73 m2) and in participants with no albuminuria (albumin to creatinine ratio [ACR] ≤30 mg/g), microalbuminuria (ACR \u3e30 to ≤300 mg/g), and macroalbuminuria (ACR \u3e300 mg/g). In per-protocol analyses, continued use of SGLT2 inhibitors was associated with a reduced risk of death compared with continued use of sulfonylureas (HR, 0.66; 95% CI, 0.60-0.74; event rate difference, -10.10; 95% CI, -12.97 to -7.24 deaths per 1000 person-years). In additional per-protocol analyses, continued use of SGLT2 inhibitors with metformin was associated with a reduced risk of death compared with SGLT2 inhibitor treatment without metformin (HR, 0.70; 95% CI, 0.50-0.97; event rate difference, -7.62; 95% CI, -17.12 to -0.48 deaths per 1000 person-years). CONCLUSIONS AND RELEVANCE: In this comparative effectiveness study analyzing data from the US Department of Veterans Affairs, among patients with type 2 diabetes receiving metformin therapy, SGLT2 inhibitor treatment was associated with a reduced risk of all-cause mortality compared with sulfonylureas. The results provide data from a real-world setting that might help guide the choice of antihyperglycemic therapy

    Clinical implications of estimated glomerular filtration rate dip following sodium-glucose cotransporter-2 inhibitor initiation on cardiovascular and kidney outcomes

    Get PDF
    Background The frequency of the initial short-term decline in estimated glomerular filtration rate (eGFR), eGFR dip, following initiation of sodium-glucose cotransporter-2 inhibitors (SGLT2i) and its clinical implications in real-world practice are not clear. Methods and Results We built a cohort of 36 638 new users of SGLT2i and 209 025 new users of other antihyperglycemics. Inverse probability weighting was used to estimate the excess rate of eGFR dip, risk of the composite cardiovascular outcome of nonfatal myocardial infarction, nonfatal stroke, hospitalization for heart failure, or all-cause mortality, and risk of the composite kidney outcome of eGFR decline \u3e50%, end-stage kidney disease, or all-cause mortality. In the first 6 months of therapy, compared with other antihyperglycemics, excess rates of eGFR dip \u3e10% and eGFR dip \u3e30% were 9.86 (95% CI: 8.83-11.00) and 1.15 (0.70-1.62) per 100 SGLT2i users, respectively. In mediation analyses that accounted for eGFR dipping, SGLT2i use was associated with reduced risk of cardiovascular and kidney outcomes (hazard ratio, 0.92 [0.84-0.99] and 0.78 [0.71-0.87], respectively); the magnitude of the association reduced by eGFR dipping was small for both outcomes. SGLT2i was associated with reduced risk of both outcomes in those with higher than average probability of eGFR dip \u3e10% or 30%. Compared with discontinuation, continued use of SGLT2i at 6 months was associated with reduced risk of cardiovascular and kidney outcomes in those with no eGFR dip or eGFR dip ≤10%, in those with eGFR dip \u3e10%, and in those with eGFR dip \u3e30%. Conclusions The salutary association of SGLT2i with cardiovascular and kidney outcomes was maintained regardless of eGFR dipping; concerns about eGFR dipping should not preclude use, and occurrence of eGFR dip after SGLT2i initiation may not warrant discontinuation

    Pelvic pain correlates with peritoneal macrophage abundance not endometriosis

    Get PDF
    Endometriosis is a chronic neuroinflammatory pain condition affecting ~180 million women worldwide. Surgical removal or hormonal suppression of endometriosis lesions only relieves pain symptoms in some women and symptomatic relapse following treatment is common. Identifying factors that contribute to pain is key to developing new therapies. We collected peritoneal fluid samples and clinical data from a cohort of women receiving diagnostic laparoscopy for suspected endometriosis (n = 52). Peritoneal fluid immune cells were analysed by flow cytometry and data compared with pain scores determined using the pain domain of the Endometriosis Health Profile Questionnaire (EHP-30) in order to investigate the association between peritoneal immune cells and pain symptoms. Pain scores were not different between women with or without endometriosis, nor did they differ according to disease stage; consistent with a poor association between disease presentation and pain symptoms. However, linear regression and correlation analysis demonstrated that peritoneal macrophage abundance correlated with the severity of pelvic pain. CD14(high) peritoneal macrophages negatively correlated with pain scores whereas CD14(low) peritoneal macrophages were positively correlated, independent of diagnostic outcome at laparoscopy. Stratification by pain subtype, rather than endometriosis diagnosis, resulted in the most robust correlation between pain and macrophage adundance. Pain score strongly correlated with CD14(high) (P = 0.007) and CD14(low) (P = 0.008) macrophages in patients with non-menstrual pain and also in patients who reported dysmennorhea (CD14(high) P = 0.021, CD14(low) P = 0.019) or dysparunia (CD14(high) P = 0.027, CD14(low) P = 0.031). These results provide new insight into the association between peritoneal macrophages and pelvic pain which may aid the identification of future therapeutic targets. LAY SUMMARY: Endometriosis is a common condition where cells similar to those that line the womb are found elsewhere in the body. It is associated with inflammation and pain in the pelvis and affects ~180 million women worldwide. Current treatments are not effective for all patients and we, therefore, need to understand what causes pain in order to develop new treatments. We investigated the types of immune cells present within the pelvis of women undergoing investigation for suspected endometriosis. Disease diagnosis and stage (I–IV) was recorded along with pain score determined by questionnaire. We characterised the immune cells present and compared them to disease stage and pain score. We found that pelvic pain was linked to the abundance of immune cells but, surprisingly, not to disease stage. These findings suggest that immune cells are closely associated with pain severity in endometriosis and may be good targets for future endometriosis treatments
    • …
    corecore