Let R be a commutative Noetherian ring. We prove that if R is either an equidimensional finitely generated algebra over a perfect field, or an equidimensional equicharacteristic complete local ring with a perfect residue field, then the annihilator of the singularity category of R coincides with the Jacobian ideal of R up to radical. We establish a relationship between the annihilator of the singularity category of R and the cohomological annihilator of R under some mild assumptions. Finally, we give an upper bound for the dimension of the singularity category of an equicharacteristic excellent local ring with isolated singularity. This extends a result of Dao and Takahashi to non-Cohen–Macaulay rings.

Quantitative information on epidemiological quantities such as the incubation period and generation time of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants is scarce. We analysed a dataset collected during contact tracing activities in the province of Reggio Emilia, Italy, throughout 2021. We determined the distributions of the incubation period for the Alpha and Delta variants using information on negative polymerase chain reaction tests and the date of last exposure from 282 symptomatic cases. We estimated the distributions of the intrinsic generation time using a Bayesian inference approach applied to 9724 SARS-CoV-2 cases clustered in 3545 households where at least one secondary case was recorded. We estimated a mean incubation period of 4.9 days (95% credible intervals, CrI, 4.4–5.4) for Alpha and 4.5 days (95% CrI 4.0–5.0) for Delta. The intrinsic generation time was estimated to have a mean of 7.12 days (95% CrI 6.27–8.44) for Alpha and of 6.52 days (95% CrI 5.54–8.43) for Delta. The household serial interval was 2.43 days (95% CrI 2.29–2.58) for Alpha and 2.74 days (95% CrI 2.62–2.88) for Delta, and the estimated proportion of pre-symptomatic transmission was 48–51% for both variants. These results indicate limited differences in the incubation period and intrinsic generation time of SARS-CoV-2 variants Alpha and Delta compared to ancestral lineages.

Previous studies have reported the basic reproduction number (R0) of coronavirus disease from publicly reported data that lack information such as onset of symptoms, presence of importations or known super-spreading events. Using data from the Republic of Korea, we illustrated how estimates of R0 can be biased and provided improved estimates with more detailed data. We used COVID-19 contact trace system in Korea, which can provide symptom onset date and also serial intervals between contacted people. The total R0 was estimated as 2.10 (95% confidence interval (CI) 1.84–2.42). Also, early transmission of COVID-19 differed by regional or social behaviours of the population. Regions affected by a specific church cluster, which showed a rapid and silent transmission under non-official religious meetings, had a higher R0 of 2.40 (95% CI 2.08–2.77).

The demographic attributes of the parthenium beetle Zygogramma bicolorata Pallister were studied using Parthenium hysterophorus L. as food under different abiotic and biotic variables. Intrinsic and finite rates of increase were highest with the shortest mean generation and doubling times when Z. bicolorata was fed on inflorescences followed by the leaves and stems of P. hysterophorus. Temperature significantly affected the demographic parameters. The net reproductive rate was highest at 27 °C and lowest at 35 °C. Different photoperiodic exposures altered the demographic attributes of the beetles with long-day exposure (14L:10D) resulting in optimal values compared with other photoperiodic exposures. Continuous darkness (0L:24D) and continuous light (24L:0D) suboptimally affected the demographic attributes of the beetles. In response to the light of different wavelengths, the net reproductive rate, and intrinsic and finite rates of increase were significantly higher when the beetles were reared under a broad spectrum of white light followed by those under ~570 nm (yellow), ~475 nm (blue) and ~650 nm (red). Information gained in this study may be helpful in the mass multiplication of Z. bicolorata, and thereby strengthening the biocontrol of parthenium weed.

This study investigated the molecular and biological variation among different Giardia duodenalis assemblages. In vitro growth and susceptibility to albendazole, fenbendazole, flubendazole, metronidazole, tinidazole and furazolidone was studied for laboratory (AI: WB, AII: G1 and B: GS/M-83-H7) and 6 field isolates of assemblage subtype AI, AII, B and EIII. Additionally, isolates of the 3 assemblages were evaluated in the gerbil upon 3-day oral treatment with albendazole (6 mg/kg), flubendazole (5 mg/kg) and metronidazole (20 mg/kg). Assemblage AI grew significantly faster than all other assemblage subtypes, which showed comparable generation times. The assemblage A laboratory strains displayed altered in vitro drug susceptibilities compared to their matching AI or AII field isolate. No variation in drug susceptibility was observed between field isolates of assemblages A and E. However, assemblage A laboratory strains were more susceptible to the benzimidazoles and less susceptible to the nitro-imidazoles and furazolidone than the assemblage B laboratory strain. In the gerbil, no markedly different drug susceptibilities were observed. In conclusion, the Giardia assemblage subtype can be associated with differences in growth characteristics rather than in drug susceptibility.