Kandungan Klorofil Tumbuhan Dominan Pasca Kebakaran Lahan Gambut dan Pemanfaatannya untuk Rancangan Lkpd Biologi SMA

This study aims to determine the effect of fire incident time on chlorophyll content of dominant plants after peat land fires in Rimba Panjang village, Kampar regency. This study was conducted during the months of February to June 2017 using the servei research design. Samples are the dominant strata sapling plant determined based on Important Value Index (IVI) with sampling using purpose random sampling technique based on gradient time of fires (2009, 2013, 2014, 2015, 2016, 2017). The measurement of chlorophyll content was done on the leaves of the three dominant strata sapling plants using Chlorophyll meter SPAD 502, while the physical chemical aspects of the environment were measured using Lux meter to measure light intensity, Thermo hygrometer to measure temperature and humidity, and Soil tester to measure pH and soil moisture. The measurement results dominant chlorophyll content in plants showed that the longer time after the fire the chlorophyll content tends to increase. In addition to the length of time after the fire, environmental factors also affect the chlorophyll content in plants such as, light intensity, soil pH, soil moisture, air temperature, and air humidity. Research result can be utilized for the design of Student WorkSheet of Biology learning in senior high school

Clinically Applicable Machine Learning Approaches to Identify Attributes of Chronic Kidney Disease (CKD) for Use in Low-Cost Diagnostic Screening.

OBJECTIVE: Chronic kidney disease (CKD) is a major public health concern worldwide. High costs of late-stage diagnosis and insufficient testing facilities can contribute to high morbidity and mortality rates in CKD patients, particularly in less developed countries. Thus, early diagnosis aided by vital parameter analytics using affordable computer-aided diagnosis could not only reduce diagnosis costs but improve patient management and outcomes. METHODS: In this study, we developed machine learning models using selective key pathological categories to identify clinical test attributes that will aid in accurate early diagnosis of CKD. Such an approach will save time and costs for diagnostic screening. We have also evaluated the performance of several classifiers with k-fold cross-validation on optimized datasets derived using these selected clinical test attributes. RESULTS: Our results suggest that the optimized datasets with important attributes perform well in diagnosis of CKD using our proposed machine learning models. Furthermore, we evaluated clinical test attributes based on urine and blood tests along with clinical parameters that have low costs of acquisition. The predictive models with the optimized and pathologically categorized attributes set yielded high levels of CKD diagnosis accuracy with random forest (RF) classifier being the best performing. CONCLUSIONS: Our machine learning approach has yielded effective predictive analytics for CKD screening which can be developed as a resource to facilitate improved CKD screening for enhanced and timely treatment plans

Young stars in the periphery of the Large Magellanic Cloud

Despite their close proximity, the complex interplay between the two Magellanic Clouds, the Milky Way, and the resulting tidal features, is still poorly understood. Recent studies have shown that the Large Magellanic Cloud (LMC) has a very extended disk strikingly perturbed in its outskirts. We search for recent star formation in the far outskirts of the LMC, out to ~30 degrees from its center. We have collected intermediate-resolution spectra of thirty-one young star candidates in the periphery of the LMC and measured their radial velocity, stellar parameters, distance and age. Our measurements confirm membership to the LMC of six targets, for which the radial velocity and distance values match well those of the Cloud. These objects are all young (10-50 Myr), main-sequence stars projected between 7 and 13 degrees from the center of the parent galaxy. We compare the velocities of our stars with those of a disk model, and find that our stars have low to moderate velocity differences with the disk model predictions, indicating that they were formed in situ. Our study demonstrates that recent star formation occurred in the far periphery of the LMC, where thus far only old objects were known. The spatial configuration of these newly-formed stars appears ring-like with a radius of 12 kpc, and a displacement of 2.6 kpc from the LMC's center. This structure, if real, would be suggestive of a star-formation episode triggered by an off-center collision between the Small Magellanic Cloud and the LMC's disk.Comment: Accepted for publication in MNRA

In-Situ Star Formation in the Outskirts of the Large Magellanic Cloud: Gaia DR2 Confirmation

We explore the Gaia DR2 proper motions of six young, main-sequence stars, members of the Large Magellanic Cloud (LMC) reported by Moni Bidin et al. (2017). These stars are located in the outskirts of the disk, between 7 and 13 degrees from the LMC's center where there is very low H I content. Gaia DR2 proper motions confirm that four stars formed locally, in situ, while two are consistent with being expelled via dynamical interactions from inner, more gas-rich regions of the LMC. This finding establishes that recent star formation occurred in the periphery of the LMC, where thus far only old populations are known.Comment: Accepted for publication in Astrophysical Journal Letter

Chemical Composition of Young Stars in the Leading Arm of the Magellanic System

Chemical abundances of eight O- and B-type stars are determined from high-resolution spectra obtained with the MIKE instrument on the Magellan 6.5m Clay telescope. The sample is selected from 42 candidates of membership in the Leading Arm of the Magellanic System. Stellar parameters are measured by two independent grids of model atmospheres and analysis procedures, confirming the consistency of the stellar parameter results. Abundances of seven elements (He, C, N, O, Mg, Si, and S) are determined for the stars, as are their radial velocities and estimates of distances and ages. Among the seven B-type stars analyzed, the five that have radial velocities compatible with membership to the LA have an average [Mg/H] of $-0.42\pm0.16$, significantly lower than the average of the remaining two [Mg/H] = $-0.07\pm0.06$ that are kinematical members of the Galactic disk. Among the five LA members, four have individual [Mg/H] abundance compatible with that in the LMC. Within errors, we can not exclude the possibility that one of these stars has a [Mg/H] consistent with the more metal-poor, SMC-like material. The remaining fifth star has a [Mg/H] close to MW values. Distances to the LA members indicate that they are at the edge of the Galactic disk, while ages are of the order of $\sim 50-70$ Myr, lower than the dynamical age of the LA, suggesting a single star-forming episode in the LA. V$_{\rm LSR}$ the LA members decreases with decreasing Magellanic longitude, confirming the results of previous LA gas studies.Comment: 61 pages, 18 figures, 5 tables. Accepted for publication in Ap

The Origins of Young Stars in the Direction of the Leading Arm of the Magellanic Stream: Abundances, Kinematics, and Orbits

We explore the origins of the young B-type stars found by Casetti-Dinescu et al.(2014) at the outskirts of the Milky-Way disk in the sky region of Leading Arm of the Magellanic Stream. High-resolution spectroscopic observations made with the MIKE instrument on the Magellan Clay 6.5m telescope for nine stars are added to the previous sample analyzed by Zhang et al. (2017). We compile a sample of fifteen young stars with well-determined stellar types, ages, abundances and kinematics. With proper motions from Gaia DR2 we also derive orbits in a realistic Milky-Way potential. We find that our previous radial-velocity selected LA candidates have substantial orbital angular momentum. The substantial amount of rotational component for these stars is in contrast with the near-polar Magellanic orbit, thus rendering these stars unlikely members of the LA. There are four large orbital-energy stars in our sample. The highest orbital-energy one has an age shorter than the time to disk crossing, with a birthplace $z=2.5$~kpc and $R_{\rm GC}\sim 28$~kpc. Therefore, the origin of this star is uncertain. The remaining three stars have disk runaway origin with birthplaces between 12 and 25 kpc from the Galactic center. Also, the most energetic stars are more metal poor ([Mg/H] =$-0.50\pm0.07$) and with larger He scatter ($\sigma_{\rm [He/H]} = 0.72$) than the inner disk ones ([Mg/H] $=0.12\pm0.36$, $\sigma_{\rm [He/H]} = 0.15$). While the former group's abundance is compatible with that of the Large Magellanic Cloud, it could also reflect the metallicity gradient of the MW disk and their runaway status via different runaway mechanisms.Comment: 58 pages, 17 figures, 7 tables. Accepted for publication in Ap

A panchromatic view of the bulge globular cluster NGC 6569

We used high-resolution optical HST/WFC3 and multi-conjugate adaptive optics assisted GEMINI GeMS/GSAOI observations in the near-infrared to investigate the physical properties of the globular cluster NGC 6569 in the Galactic bulge. We have obtained the deepest purely NIR color-magnitude diagram published so far for this cluster using ground-based observations, reaching $K_{s}$ $\approx$ 21.0 mag (two magnitudes below the main-sequence turn-off point). By combining the two datasets secured at two different epochs, we determined relative proper motions for a large sample of individual stars in the center of NGC 6569, allowing a robust selection of cluster member stars. Our proper motion analysis solidly demonstrates that, despite its relatively high metal content, NGC 6569 hosts some blue horizontal branch stars. A differential reddening map has been derived in the direction of the system, revealing a maximum color excess variation of about $\delta E(B-V)$ $\sim$ 0.12 mag in the available field of view. The absolute age of NGC 6569 has been determined for the first time. In agreement with the other few bulge globular clusters with available age estimates, NGC 6569 turns out to be old, with an age of about 12.8 Gyr, and a typical uncertainty of 0.8-1.0 Gyr.Comment: 25 pages, 16 Figures, 1 Table. Accepted for publication in Ap