Manifold Path Guiding for Importance Sampling Specular Chains

Complex visual effects such as caustics are often produced by light paths containing multiple consecutive specular vertices (dubbed specular chains), which pose a challenge to unbiased estimation in Monte Carlo rendering. In this work, we study the light transport behavior within a sub-path that is comprised of a specular chain and two non-specular separators. We show that the specular manifolds formed by all the sub-paths could be exploited to provide coherence among sub-paths. By reconstructing continuous energy distributions from historical and coherent sub-paths, seed chains can be generated in the context of importance sampling and converge to admissible chains through manifold walks. We verify that importance sampling the seed chain in the continuous space reaches the goal of importance sampling the discrete admissible specular chain. Based on these observations and theoretical analyses, a progressive pipeline, manifold path guiding, is designed and implemented to importance sample challenging paths featuring long specular chains. To our best knowledge, this is the first general framework for importance sampling discrete specular chains in regular Monte Carlo rendering. Extensive experiments demonstrate that our method outperforms state-of-the-art unbiased solutions with up to 40x variance reduction, especially in typical scenes containing long specular chains and complex visibility.Comment: 14 pages, 19 figure

Allogeneic hematopoietic stem cell transplantation for acute leukemia with Gilbert's syndrome

Acute leukemia with coexisting Gilbert's syndrome treated by allogeneic hematopoietic stem cell transplantation (allo-HSCT) is rarely reported. Here we described a case whose transaminase levels were almost normal, although transient hyperbilirubinemia repeatedly happened during chemotherapy

Benzyl (E)-3-(2-bromo-5-meth­oxy­benzyl­idene)dithio­carbazate

The title compound, C16H15BrN2OS2, was obtained from the condensation reaction of benzyl dithio­carbazate and 2-bromo-5-meth­oxy­lbenzaldehyde. In the mol­ecule, the bromo­meth­oxy­phenyl ring and dithio­carbazate fragment are located on the opposite sides of the C=N double bond, showing the E conformation. The dithio­carbazate fragment is approximately planar (r.m.s deviation 0.0187 Å); its mean plane is oriented with respect to the bromo­meth­oxy­phenyl and phenyl rings at 7.60 (12) and 60.08 (9)°, respectively. In the crystal, inversion dimers linked by pairs of N—H⋯S hydrogen bonds occur. A short Br⋯Br contact of 3.5526 (12) Å is observed in the crystal structure

Strand bias in complementary single-nucleotide polymorphisms of transcribed human sequences: evidence for functional effects of synonymous polymorphisms

BACKGROUND: Complementary single-nucleotide polymorphisms (SNPs) may not be distributed equally between two DNA strands if the strands are functionally distinct, such as in transcribed genes. In introns, an excess of A↔G over the complementary C↔T substitutions had previously been found and attributed to transcription-coupled repair (TCR), demonstrating the valuable functional clues that can be obtained by studying such asymmetry. Here we studied asymmetry of human synonymous SNPs (sSNPs) in the fourfold degenerate (FFD) sites as compared to intronic SNPs (iSNPs). RESULTS: The identities of the ancestral bases and the direction of mutations were inferred from human-chimpanzee genomic alignment. After correction for background nucleotide composition, excess of A→G over the complementary T→C polymorphisms, which was observed previously and can be explained by TCR, was confirmed in FFD SNPs and iSNPs. However, when SNPs were separately examined according to whether they mapped to a CpG dinucleotide or not, an excess of C→T over G→A polymorphisms was found in non-CpG site FFD SNPs but was absent from iSNPs and CpG site FFD SNPs. CONCLUSION: The genome-wide discrepancy of human FFD SNPs provides novel evidence for widespread selective pressure due to functional effects of sSNPs. The similar asymmetry pattern of FFD SNPs and iSNPs that map to a CpG can be explained by transcription-coupled mechanisms, including TCR and transcription-coupled mutation. Because of the hypermutability of CpG sites, more CpG site FFD SNPs are relatively younger and have confronted less selection effect than non-CpG FFD SNPs, which can explain the asymmetric discrepancy of CpG site FFD SNPs vs. non-CpG site FFD SNPs

Diaqua­bis­(5-methyl­pyrazine-2-carboxyl­ato-κ2 N 1,O)cobalt(II) dihydrate

In the title complex, [Co(C6H5N2O2)2(H2O)2]·2H2O, the coordination geometry of the Co2+ cation is distorted octa­hedral, with two N atoms and two O atoms from two 5-methyl­pyrazine-2-carboxyl­ate ligands in the equatorial plane. The two remaining coordination sites are occupied by two water mol­ecules. In addition, there are two uncoordinated water mol­ecules in the asymmetric unit. The crystal structure is stabilized by a network of O—H⋯O and O—H⋯N hydrogen-bonding inter­actions, forming a three-dimensional structure

Investigation of preoperative physical activity level in kidney transplant recipients and its impact on early postoperative recovery: A retrospective cohort study

ObjectiveTo retrospectively investigate the preoperative physical activity (PA) level in kidney transplant recipients (KTRs) and its impact on early postoperative recovery.MethodsA total of 113 patients who received kidney transplantation at West China Hospital of Sichuan University were enrolled in this retrospective cohort study. According to the PA level measured by the Chinese version of the International Physical Activity Questionnaire—Long Version, the patients were allocated into the low PA level group (Group L, n = 55) and medium to high PA level group (Group MH, n = 58). The kidney function recovery indicators, including estimated glomerular filtration rate (eGFR), postoperative complications, postoperative length of stay (LOS), and unscheduled readmission within three months of discharge, were evaluated and documented. A association analysis was applied to analyze and compare the association between indicators.ResultsThe median PA levels of the KTRs were 1701.0 MTEs * min/week. Regarding the postoperative recovery indicators, the KTRs spent a mean time of 19.63 h to achieve transfer out of bed after the operation (Group L: 19.67 h; Group MH: 19.53 h; P = 0.952) and reached a mean distance of 183.10 m as the best ambulatory training score within two days after the operation (Group L: 134.91 m; Group MH: 228.79 m; P < 0.001). The preoperative PA level showed a moderate positive association with early postoperative ambulation distance (ρ = 0.497, P < 0.001). However, no significant between-group difference in eGFR on postoperative days 1, 3, and 5 (P = 0.913, 0.335, and 0.524) or postoperative complications, including DGF (P = 0.436), infection (P = 0.479), postoperative LOS (P = 0.103), and unscheduled readmission (P = 0.698), was found.ConclusionsThe preoperative PA level of KTRs is lower than that of the general population. KTRs with moderate or high preoperative PA levels showed higher ambulatory function in the early postoperative period than those with low preoperative PA levels, but no between-group differences in other early recovery indicators were observed

Pharmacologic Prophylaxis of Portal Venous System Thrombosis after Splenectomy: A Meta-Analysis

Portal venous system thrombosis (PVST) is a life-threatening complication of splenectomy. A meta-analysis was conducted to explore the role of pharmacologic prophylaxis of PVST after splenectomy. Overall, 359 papers were initially identified via the PubMed, EMBASE, and Cochrane Library databases. Eight of them were eligible. The incidence of PVST after splenectomy was significantly lower in patients who received the preventive measures than in those who did not (odds ratio [OR]: 0.33, 95% confidence interval [CI]: 0.22–0.47, P<0.00001). Subgroup analyses demonstrated that the significant difference remained in studies including patients with portal hypertension (n=6), but not in those including patients with hematological diseases (n=2); the significant difference remained in studies using any type of prophylactic drugs (anticoagulants [n=6], thrombolytics [n=1], and prostaglandin E1 [n=1]); the significant difference remained in nonrandomized studies (n=5), but not in randomized studies (n=3). The risk of bleeding was similar between the two groups (OR: 0.65, 95% CI: 0.10–4.04, P=0.64). In conclusion, pharmacologic prophylaxis might decrease the incidence of PVST after splenectomy in patients with portal hypertension and did not increase the risk of bleeding. However, the effect of pharmacologic prophylaxis of PVST in patients with hematological diseases remained questioned

Exploring the multiband gravitational wave background with a semi-analytic galaxy formation model

An enormous number of compact binary systems, spanning from stellar to supermassive levels, emit substantial gravitational waves during their final evolutionary stages, thereby creating a stochastic gravitational wave background (SGWB). We calculate the merger rates of stellar compact binaries and massive black hole binaries using a semi-analytic galaxy formation model -- Galaxy Assembly with Binary Evolution (GABE) in a unified and self-consistent approach, followed by an estimation of the multi-band SGWB contributed by those systems. We find that the amplitudes of the principal peaks of the SGWB energy density are within one order of magnitude $\Omega_{GW} \sim 10^{-9}- 10^{-8}$. This SGWB could easily be detected by the Square Kilometre Array (SKA), as well as planned interferometric detectors, such as the Einstein Telescope (ET) and the Laser Interferometer Space Antenna (LISA). The energy density of this background varies as $\Omega_{GW} \propto f^{2/3}$ in SKA band. The shape of the SGWB spectrum in the frequency range $\sim[10^{-4}$,$1]$Hz could allow the LISA to distinguish the black hole seed models. The amplitude of the SGWB from merging stellar binary black holes (BBHs) at $\sim 100$ Hz is approximately 10 and 100 times greater than those from merging binary neutron stars (BNSs) and neutron-star-black-hole (NSBH) mergers, respectively. Note that, since the cosmic star formation rate density predicted by GABE is somewhat lower than observational results by $\sim 0.2$ dex at z < $\sim 2$, the amplitude of the SGWB in the frequency range $\sim[1$, $10^{4}]$ Hz may be underestimated by a similar factor at most.Comment: 12 pages, 5 figure