Evaluation of the B/F Ratio Distribution of Cataract Patients Without Corneal Abnormalities and Its Effect on Ocular Parameters

Purpose: To evaluate the distribution of the posterior-anterior corneal radius ratio (B/F ratio; posterior corneal radius/anterior corneal radius) in patients without corneal abnormalities, and to investigate which parameters affect this ratio. Methods: Five thousand eyes from 5,000 patients who underwent cataract surgery were recruited to this study. We explored the linear relationship between B/F ratio and 13 variables using Principal Component-Multivariate Linear Regression Analysis. Results: The B/F ratio was negatively correlated with the difference between simulated keratometry (SimK) and true net power (TNP), central corneal thickness, spherical aberration (SA), and posterior corneal astigmatism and positively correlated with posterior corneal radius, corneal posterior surface, axial length (AL) and anterior corneal radius. Several variables (central corneal thickness, difference between SimK and TNP and asphericity coefficient (Q-value) of the posterior corneal surface) had the highest loading on the final score. B/F ratio reflects the refractive state and anatomical structure of the cornea: thus, higher B/F ratios were associated with larger posterior corneal surface curvature radius, longer axial length, thinner central corneal thickness, lower high order aberrations of the cornea and SA, and the numerical difference between simK and TNP gradually reduced. In clinical practice, for patients with lower B/F ratio, special care should be taken in the choice of system used for intraocular lens (IOL) measurements.

Efektivitas Penerapan Pembiayaan Musyarakah Pada Baitul Maal Wa Tamwil (BMT) Bima Kota Magelang

<p><em>The purpose of this study was to determine the effectiveness of the profit-sharing Musyarakah financing procedure at BMT BIMA Magelang. This study is a qualitative research, uses field research. Data collection techniques through interviews, documentation, and observation, while data analysis techniques using descriptive analysis techniques. The results of the study found that the Musyarakah financing procedure at BMT BIMA Magelang has been carried out effectively because it has carried out the financing process according to sharia principles and provisions, namely, an ijab qabul process between the customer and the BMT, the parties who make contracts, an object of the capital agreement, and a transparent ratio distribution of profits and losses. This study shows that for every increase in the use of Musyarakah financing, there is also an increase in the income of BMT BIMA Magelang.</em></p>

Period Ratio Sculpting near Second-order Mean-motion Resonances

Second-order mean-motion resonances lead to an interesting phenomenon in the sculpting of the period-ratio distribution, due to their shape and width in period-ratio/eccentricity space. As the osculating periods librate in resonance, the time-averaged period ratio approaches the exact commensurability. The width of second-order resonances increases with increasing eccentricity, and thus more eccentric systems have a stronger peak at commensurability when averaged over sufficient time. The libration period is short enough that this time-averaging behavior is expected to appear on the timescale of the Kepler mission. Using N-body integrations of simulated planet pairs near the 5:3 and 3:1 mean-motion resonances, we investigate the eccentricity distribution consistent with the planet pairs observed by Kepler. This analysis, an approach independent from previous studies, shows no statistically significant peak at the 3:1 resonance and a small peak at the 5:3 resonance, placing an upper limit on the Rayleigh scale parameter, σ, of the eccentricity of the observed Kepler planets at σ = 0.245 (3:1) and σ = 0.095 (5:3) at 95% confidence, consistent with previous results from other methods.

X-ray source population in the polar ring galaxy NGC 660 as observed by Chandra

We present Chandra observations of the nearby polar ring galaxy NGC 660 to study its X-ray source population. Based on our analysis, we detected a total of 23 X-ray sources in the 0.5−8 keV band, with luminosities ranging from ∼1037 to ∼1039 erg s−1. Twenty-two of these sources are located off-nuclear and have luminosities below the ultraluminous X-ray source (ULX) threshold value of L 0.5−8 keV < 1039 erg s−1, suggesting that they are likely to be X-ray binary (XRB) candidates. The remaining source is located at the center of the galaxy, suggesting it is an active galactic nucleus (AGN). However, we estimated that four of the detected sources could be associated with background objects. Based on the source count rates in each of the Chandra observations, we found evidence for variability in nine of the 23 sources, including the AGN. However, further investigation with spectral analysis suggested no significant differences in the AGN luminosities between the observations. The X-ray luminosity distribution of the galaxy was found to be generally lower than that expected from previous studies on star forming and collisional ring galaxies. No ULX was also detected in the galaxy, in contrast with what was expected from the galaxyʼs SFR and metallicity (i.e., SFR = 14.43 ± 0.19 M ⊙ yr−1 and Z = 0.94 ± 0.01 Z ⊙, respectively). These results suggest a deficit in the X-ray sources detected. Based on source hardness ratio distribution, we found evidence that the fainter sources have a harder source spectrum, indicating higher absorption. This further suggests that there could be more X-ray sources that were not detected in the galaxy due to significant obscuration.

Probing Early Supermassive Black Hole Growth and Quasar Evolution with Near-infrared Spectroscopy of 37 Reionization-era Quasars at 6.3 < z ≤ 7.64

We report the results of near-infrared spectroscopic observations of 37 quasars in the redshift range 6.3 < z ≤ 7.64, including 32 quasars at z > 6.5, forming the largest quasar near-infrared spectral sample at this redshift. The spectra, taken with Keck, Gemini, VLT, and Magellan, allow investigations of central black hole mass and quasar rest-frame ultraviolet spectral properties. The black hole masses derived from the Mg ii emission lines are in the range (0.3–3.6) × 109 M ⊙, which requires massive seed black holes with masses ≳103–104 M ⊙, assuming Eddington accretion since z = 30. The Eddington ratio distribution peaks at λ Edd ∼ 0.8 and has a mean of 1.08, suggesting high accretion rates for these quasars. The C iv–Mg ii emission-line velocity differences in our sample show an increase of C iv blueshift toward higher redshift, but the evolutionary trend observed from this sample is weaker than the previous results from smaller samples at similar redshift. The Fe ii/Mg ii flux ratios derived for these quasars up to z = 7.6, compared with previous measurements at different redshifts, do not show any evidence of strong redshift evolution, suggesting metal-enriched environments in these quasars. Using this quasar sample, we create a quasar composite spectrum for z > 6.5 quasars and find no significant redshift evolution of quasar broad emission lines and continuum slope, except for a blueshift of the C iv line. Our sample yields a strong broad absorption line quasar fraction of ∼24%, higher than the fractions in lower-redshift quasar samples, although this could be affected by small sample statistics and selection effects.

High Mass-Ratio Binary Population in Open Clusters: Segregation of Early Type Binaries and an Increasing Binary Fraction with Mass

Binary stars play a vital role in astrophysical research, as a good fraction of stars are in binaries. Binary fraction (BF) is known to change with stellar mass in the Galactic field, but such studies in clusters require binary identification and membership information. Here, we estimate the total and spectral-type high-mass-ratio (HMR) BF (f 0.6) in 23 open clusters using unresolved binaries in color–magnitude diagrams using Gaia DR2 data. We introduce the segregation index (   ) parameter to trace mass segregation of HMR (total and mass) binaries and the reference population. This study finds that in open clusters, (1) HMR BF for the mass range 0.4–3.6 M ⊙ (early M to late B-type stars) has a range of 0.12–0.38 with a peak at 0.12–0.20; (2) older clusters have a relatively higher HMR BF; (3) the mass-ratio distribution is unlikely to be a flat distribution and BF (total) ∼(1.5–2.5) × f 0.6; (4) a decreasing BF (total) from late B to K-type stars, in agreement with the Galactic field stars; (5) older clusters show radial segregation of HMR binaries; (6) B-type and A–F type HMR binaries show radial segregation in some young clusters suggesting a primordial origin. This study will constrain the initial conditions and identify the major mechanisms that regulate binary formation in clusters. Primordial segregation of HMR binaries could result from massive clumps spatially segregated in the collapse phase of the molecular cloud.

Characterizing Permeability from Geological and Geochemical Data in the Olkaria Domes Field in Kenya.

Olkaria geothermal field is located in the Kenyan Rift Valley that is a part of the Great East Africa Rift System (EARS). The geothermal field continues to be associated with a high geothermal gradient that arises from shallow magmatic activities which are ongoing in the enormous igneous province. Exploration and drilling of wells that were undertaken in the past revealed the existence of exploitable geothermal steam. The Olkaria field is divided into seven sections namely; Olkaria East field, Olkaria North East field, Olkaria North West field, Olkaria South East field, Olkaria South West field, Olkaria Central field, and Olkaria Domes field. The productivity of the geothermal wells continues to be influenced by factors such as subsurface permeability. Permeability is one of the parameters used for the characterization of geothermal fields. Other parameters used for characterization are associated with geotechnical weak zones and include features such as; fractures, vein bodies, and deformational fault systems. The research work involved geoscientific characteristics of the Olkaria Domes field based on the geological and geochemical factors to characterize the permeability of the field. The research involved studying rock types in the area by analysing drill cuttings obtained from six drilled wells in the Olkaria Domes field. Three of the six drill wells were considered for correlative description for the purpose of this paper. Correlation of the main lithologies and zones for loss of circulation in the field was also undertaken as well as the creation of mineralogical maps to capture the distribution of the minerals that were derived from hydrothermal weathering processes. The depths and formation for major loss circulation zones in the reservoir section of the field were identified and included in the description. Analysis of soil gas survey using radon as a geochemical tool in the Domes field was also carried out successfully. The relatively high levels of the soil gas ratios that were analysed captured the ratio distribution of carbon dioxide to radon at various reservoir depths. The detection of the two gases at the surface showed the existence of permeable zones which facilitated the movement of the gases through the fault-controlled structural systems of the studied Olkaria Domes field.

State of Stress in Azeri-Chirag-Gunashli Anticline Structure, South Caspian Sea

The Azeri-Chirag-Gunashli (ACG) field, a tightly folded anticline structure, located offshore Azerbaijan in the south Caspian basin, is one of the most tectonically active regions of the world. Understanding the stress state across the ACG structure is a key to successful development of the field by optimizing well placement during drilling, completion, and depletion/injection phases. This article summarizes the results of studies undertaken on the state of the stress in ACG field. It encompasses the field-wide overview of stresses from a structural standpoint, the compilation of drilling and completion events, for instance, induced fracture during lost circulation events, and Formation Pressure Integrity Tests (FPIT) as well as analysis of wellbore breakout from variety of sources including borehole image data and caliper logs that were used to infer the magnitude and orientation of far-field stresses. Key outcomes of this study are the stress ratio distribution maps and stress orientation maps across the structure, based on the magnitude and orientations of stresses that were inferred from drilling events and wellbore breakouts. Results of this analysis show that magnitude and orientation of stresses vary across the structure both laterally and vertically. Minimum principal stress (Shmin) tends to increase from the crest toward the flanks. The maximum principal stress (SHmax) orientation is found to be predominantly sub-perpendicular to the strike of the anticline structure (60°-80° N), influenced by the reginal tectonic stresses. Moreover, stress rotation from sub-perpendicular to sub-parallel to the anticline is observed over some parts of the central and crestal areas, indicating that stresses are less compressional at the center and crest of the Azeri anticline. Local variability is possibly due to proximity to geological features such as mud volcanos, faults, and high deformation areas. The relative magnitude of stresses found in ACG, suggests a predominantly strike-slip faulting regime (where SHmax is the greatest of the three principal stresses) particularly, at the flanks and noses of the structure.

Biomorphometry of coconut crabs (Birgus latro) in Laigoma Island, North Maluku, Indonesia

Coconut crab is a coastal animal that lives in costal forest on islands of tropical Indo-Pacific. Crab populations are currently under threat of extinction. Several issues contribute to this, including high levels of exploitation, degradation of their native habitat, land clearance, and plantations development. This study aimed to examine the biomorphometric of coconut crabs, which includes the composition, sex ratio, distribution, widht and weight relation, condition factors and gonad maturity level. The descriptive explorative methods was used in this research. The results showed that the composition of 156 coconut crabs consisted of 82 females. The results obtained a balanced sex ratio. The size of the carapace width obtained ranged from 40.15 to 88.55 mm, with a weight of 150-565 grams. The relationship between width and capacity is allometric. The values obtained from these factors ranged from 1.01 to 1.03 for men and 1.01 to 1.012 for females. The gonad maturity level of male and female mud crabs was dominated by TKG III and IV. This indicated that the research time was in spawning period.

The transition to NDC in Italy: assessing distributive and financial effects

Moving from a Defined Benefit (DB) to a Notional Defined Contribution (NDC) pension formula creates significant re-distributive effects. We estimate the amount and the intensity of these effects in the case of the Italian transition to NDC, which began in 1995. Based on administrative data of the main Italian pension scheme (FPLD), we study the evolution of yearly inequality within old-age pension benefits. Furthermore, we study the adequacy and the actuarial fairness of the pension system, by estimating the replacement rates and the Net Present Value Ratio distribution for workers who retired in the period 1996–2019. Our results show that the very generous interpretation of acquired rights determined by the 1995 reform has contributed to maintaining a high level of adequacy and a significant level of intergenerational imbalance. The financial costs of this imbalance are estimated and its extent is significant.