Biodiversity survey and estimation for line-transect sampling.

Conducting biodiversity surveys using a fully randomised design can be difficult due to budgetary constraints (e.g., the cost of labour), site accessibility, and other constraints. To this end, ecologists usually select representative line transects or quadrats from a studied area to collect individuals of a given species and use this information to estimate the levels of biodiversity over an entire region. However, commonly used biodiversity estimators such as Rao's quadratic diversity index (and especially the Gini-Simpson index) were developed based on the assumption of independent sampling of individuals. Therefore, their performance can be compromised or even misleading when applied to species abundance datasets that are collected from non-independent sampling. In this study, we utilise a Markov chain model and derive an associated parameter estimator to account for non-independence in sequential sampling. Empirical tests on two forest plots in tropical (Barro Colorado, Island of Panama) and subtropical (Heishiding Nature Reserve of Guangdong, China) regions and the continental-scale spatial distribution of Acacia species in Australia showed that our estimators performed reasonably well. The estimated parameter measuring the degree of non-independence of subsequent sampling showed that a non-independent effect is very likely to occur when using line transects to sample organisms in subtropical regions at both local and regional spatial scales. In summary, based on a first-order Markov sampling model and using Rao's quadratic diversity index as an example, our study provides an improvement in diversity estimation while simultaneously accounting for the non-independence of sampling in field biodiversity surveys. Our study presents one possible solution for addressing the non-independent sampling of individuals in biodiversity surveys.

Alcohol-Guided Growth of Two-Dimensional Narrow-Band Red-Emitting K2TiF6:Mn4+ for White-Light-Emitting Diodes.

The use of red phosphors with low light-scattering loss could improve the luminous efficacy and color rendering of white-light-emitting diodes (LEDs). Thus, the discovery of such phosphors is highly desired. In this work, high-efficiency two-dimensional red-emitting K2TiF6:Mn4+ (KTFM) were synthesized via an alcohol-assisted coprecipitation route. The synergistic effects of 1-propanol and hydrofluoric acid on the growth of KTFM microsheets (MSs) were studied through the first-principles calculations, which revealed that 1-propanol promoted the growth of KTFM MSs by preferentially adsorbing on the H-terminated K2TiF6 (001) surface. The photoluminescence quantum efficiency (QE) of Mn4+-activated K2TiF6 MSs was highly related to their size and thickness. The morphology-optimal KTFM MSs presented high internal QE (>90%), external QE (>71%), and thermal quenching temperature (102% at 150 °C relative to that at 25 °C). A prototype phosphor-converted LED with KTFM as the red-emitting component showed excellent color rendition ( Ra = 91, R9 = 79) and high luminous efficacy (LE = 156 lm/w).

Hyperlipidemia and statins use for the risk of new-onset anxiety/depression in patients with head and neck cancer: A population-based study.

OBJECTIVE: Anxiety/depression is common among patients with head and neck cancer (HNC), and can negatively affect treatment compliance and outcome. The aim of this study was to assess the association between hyperlipidemia and the risk of new-onset anxiety/depression after the diagnosis of HNC and the influence of administering statins. METHODS: A matched longitudinal cohort study of 1632 subjects (408 HNC patients with preexisting hyperlipidemia and 1224 age- and sex-matched HNC patients without hyperlipidemia) was included and analyzed by using data from Taiwan's National Health Insurance Research Database from January 1996 to December 2012. The incidence and hazard ratios (HRs) for the development of new-onset anxiety/depression were examined between the two groups. Cox proportional hazard regression was applied to estimate the relative risks of anxiety/depressive disorders adjusted for potential confounding factors. To estimate the risks of anxiety/depression in different sub-groups, a stratified analysis was also used. RESULTS: HNC patients with preexisting hyperlipidemia had a higher risk for comorbidities such as hypertension, diabetes mellitus, and cardiovascular disease (P <0.001). The incidence rate of anxiety/depression in the HNC patients with preexisting hyperlipidemia was also significantly higher than that among patients without hyperlipidemia (10.78% vs 7.27%, respectively; P = 0.03). A Cox regression model revealed that preexisting hyperlipidemia was an independent risk factor for anxiety/depression (aHR, 1.96; 95% CI, 1.30-2.94). Statins use was protective against anxiety/depression among HNC patients with hyperlipidemia (aHR, 0.85; 95% CI, 0.46-1.57), especially for individuals older than 65 years and for females. CONCLUSIONS: Preexisting hyperlipidemia was associated with increased risk of new-onset anxiety/depression in the HNC patients. Statins use for HNC patients with hyperlipidemia could decrease the risk of anxiety/depression, especially for those older than 65 years and for female patients.

[Impact of different temperatures and ambient PM2.5 on the cytotoxicity and cytophagocytic function of alveolar macrophages of rat].

OBJECTIVE: To investigate the interactive effects of different temperatures and ambient PM2.5 on the rat alveolar macrophages. METHODS: The rat alveolar macrophages were collected. The cells were exposed in vitro to 18℃, 24℃, 30℃, 37℃ and 43℃ with PM2.5 at the concentrations of 100 µg/ml, 50 µg/ml, 25 µg/ml and 0 µg/ml respectively. The cells were cultured in the different cases for 8 hours, then cytotoxicity was assessed by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide(MTT)reduction assay and phagocytosis function of macrophages was assessed by neutral red absorption test. RESULTS: The relative survival rate and the cytophagocytic function of alveolar macrophages of rats among the different concentration groups decreased significantly (P<0.05) compared with the blank control group. Both were dose-dependent. The 37℃ group had the highest level of relative survival rate and the cytophagocytic function compared with other different temperatures groups. Interactive effect of different temperatures and ambient PM2.5 was not observed. But the lower temperature and the higher PM2.5 concentration group had stronger toxicity to alveolar macrophages. CONCLUSIONS: The results suggested that different temperatures and ambient PM2.5 have cytotoxicity on alveolar macrophages,injuring the phagocytosis. The two factors had some interaction.

Theoretical investigations of the reactivities of cationic six-membered carbene analogues of group 14 elements.

The potential energy surfaces for the chemical reactions of cationic six-membered group 14 heavy carbene species have been studied using density functional theory (B3LYP/LANL2DZ) and CCSD (CCSD/LANL2DZ//B3LYP/LANL2DZ) methods. Five six-membered group 14 cationic heavy carbene species, [HC(CMeNPh)2E:](+), where E = C, Si, Ge, Sn, and Pb, have been chosen as model reactants in this work. Also, four kinds of chemical reaction, C-H bond insertion, multiple bond cycloaddition, dimerization, and O-H bond insertion, have been used to study the chemical reactivities of these group 14 cationic carbene species. Basically, our present theoretical work predicts that the larger the angle NEN bond angle and the smaller the singlet-triplet splitting of the carbene, the lower its activation barriers will be and, in turn, the more rapid are its chemical reactions with other species. Moreover, the theoretical investigations suggest that the relative carbenic reactivity decreases in the order C > Si > Ge > Sn > Pb. That is, the heavier the group 14 atom (E), the more stable is its cationic carbene toward chemical reaction. As a result, we predict that the cationic six-membered group 14 carbene species (E = C, Si, Ge, Sn, and Pb) should be stable, readily synthesized, and isolated at room temperature. Our computational results are in good agreement with the available experimental observations. Furthermore, the singlet-triplet energy splitting of the carbene, as described in the configuration mixing model attributed to the work of Pross and Shaik, can be used as a diagnostic tool to predict its reactivities. The results obtained allow a number of predictions to be made.