Synthesis of ordered mesoporous silica from biomass ash and its application in CO2 adsorption.

It is possible to achieve high-value utilization of solid wastes and lower the cost of mesoporous silica synthesis by synthesizing mesoporous silica from solid wastes. In this study, silica was extracted using the alkali fusion method using biomass ash as the starting material. Biomass ash based mesoporous silica was successfully prepared by hydrothermal method with silicon extract solution as silicon source. The optimum conditions for preparation were determined as follows: addition of cetyltrimethylammonium bromide was 0.45g, hydrothermal temperature was 120 °C, hydrothermal time was 24h. The prepared mesoporous silicon was systematically characterized, and the results showed that high surface area (495 m2/g) and ordered pore structure appeared in the synthesized mesoporous silica materials. The synthesized mesoporous silica showed excellent CO2 adsorption performance (0.749 mmol/g) at 25 °C and 1 bar. According to the calculation of adsorption isotherm and thermodynamics, non-linear Freundlich model can fit the adsorption isotherm better and the adsorption heat of mesoporous silica is less than 20 kJ/mol, which belongs to physical adsorption. After five cycles of CO2 adsorption, the adsorption property was still above 90%, and the CO2/N2 adsorption selectivity reached 396.6, showing good regeneration performance and adsorption selectivity. This research can provide a new possibility for the high-value exploitation of biomass ash and reducing the cost of synthetic mesoporous silica.

Risks Assessment Associated with Different Sources of Metals in Abandoned Soil of Zhuxianzhuang Coal Mine, Huaibei Coalfield (Anhui, China).

In this paper, the 36 topsoil (0-10 cm) samples were collected and the contents of Cr, Mn, Co, Ni, Cu, Zn, As, Cd and Pb were analyzed. The results indicated that the contents of Cu and As in all samples exceeded the soil background values of Anhui province, while the Co and Pb contents were lower than the background values. Geo-statistics and positive matrix factorization were applied to identify the sources of soil heavy metals, which were nature factor (15.7%), industrial activities (21.2%), coal mine (50.9%) and traffic emission (12.2%), respectively. The calculation results of health risk model based on positive matrix factorization model showed that coal mine activities accounted for the largest proportion of total source contribution, followed by industrial activities. In addition, compared with adults, the trend of health risk of children from four sources in three lands were same as adults, but their health risk was higher than adults.

Rapid determination of lignosulfonate depolymerization products by advanced polymer chromatography.

Depolymerized lignin products are very complex mixtures. Based on a depolymerization solution of commercially available sodium lignosulfonate under mild conditions, a fast and efficient method for the separation and direct characterization of the degree and efficiency of the acid-catalyzed depolymerization of lignin was developed in this study. Using an ultraviolet detector, the depolymerized lignosulfonate products were well separated and characterized according to the relative molar mass distribution on an advanced polymer chromatographic system with three ethylene-bridged hybrid columns having small pore sizes (45 Å) in series and tetrahydrofuran as the mobile phase. The developed advanced polymer chromatography method enabled the detection of low-molecular-weight lignin degradation products (Mn  = 260-1100 Da) with high peak resolutions in less than 7.2 min. Furthermore, preliminary advanced polymer chromatography studies to determine the influence of reaction temperature on the depolymerized products indicated that the depolymerized aromatics fell in several molecular weight ranges with an extremely low dispersity. This new approach can be used for the rapid analysis of lignin depolymerization products.

[Experimental Study and DFT Calculation of FTIR, FT-Raman and THz-TDS Spectra of â and â ¢ Polymorphs of Chlorpropamide].

The absorption spectra of Ⅰ and Ⅲ polymorphs of chlorpropamide were measured with terahertz time-domain spectroscopy (THz-TDS) technique, FT-IR and FT-Raman at room temperature. The results showed that there were distinct differences of Ⅰ and Ⅲ polymorphs of chlorpropamide in those spectra. The IR spectra of two polymorphs of chlorpropamide had showed differences both in the frequencies of the vibrational bands and in the relative band intensities. The obvious differences in Raman spectra of polymorphs of chlorpropamide were that the characteristic peaks of Ⅲ- form were more than Ⅰ-form in 100~1 800 cm-1 region. Absorption peaks observing in the terahertz spectra ofⅠ-form were at 0.90, 1.09 and 1.29 THz and Ⅲ-form were at 0.92, 1.11, 1.23 and 1.63 THz. The maximum difference between Ⅰ-form and Ⅲ-form was that the strong peak appeared at 1.63 THz of Ⅲ-form. The characteristic absorption bands of two polymorphs of chlorpropamide were assigned based on the simulation results of DFT calculation. The simulation result is in accordance with the experiment. From simulation results, it is found that the vibration modes of Ⅰ-form and Ⅲ-form were similar in IR and Raman spectra, but there were more differences in terahertz spectra. The study can provide experimental and theoretical references for the application of FT-IR , FT-Raman and THz-TDS spectra techniques to detect pharmaceutical polymorphs.

Characteristics of trace elements and potential environmental risks of the ash from agricultural straw direct combustion biomass power plant.

The rapid expansion of biomass power generation has resulted in a large amount of ash, which need to be treated urgently. The trace elements in ash also have environmental risks during treatment. Therefore, the essential characteristics and potential environmental risks of biomass ash generated by direct combustion of agricultural straw were studied. The leaching characteristics of elements, including major elements (Mg, K, Ca) and trace elements (V, Cr, Mn, Co, Ni, Cu, Zn, Cd, As, Pb and Ba), in fly ash and slag produced by biomass power plant were analyzed through the static leaching experiments of simulating the possible pH value of natural water in the laboratory. The results show that the trace elements are enriched in fly ash and slag, which may be related to the volatility of elements during combustion. And during the leaching test, the leaching concentration of major and trace elements in fly ash is higher than that in slag. Sequential chemical extraction is used to reveal the occurrence forms of trace elements in biomass ash. Except for residue, Mn, Co, Zn, Cd, and Pb in fly ash mainly exist in carbonate bound, V and As are Fe-Mn oxides bound, and Cr, Ni, Cu, and Ba are mainly organic matter bound. In the slag, Cd is mainly carbonate bound, Cu is mainly organic matter bound, while other elements are mainly Fe-Mn oxides bound. The Risk Assessment Code values calculated based on the existing forms of elements show that As and Cd in slag and Mn, Co, Pb and Cd in fly ash need special attention during utilization. The research results can provide reference for the management and utilization of biomass ash.

Implications for TB control among migrants in large cities in China: A prospective population-based genomic epidemiology study in Shenzhen.

Internal migrants are a challenge for TB control in large Chinese cities and understanding this epidemiology is crucial for designing effective control and prevention strategies. We conducted a prospective genomic epidemiological study of culture-positive TB patients diagnosed between June 1, 2018 and May 31, 2021 in the Longhua District of Shenzhen. Treatment status was obtained from local and national TB registries and all isolates were sequenced. Genomic clusters were defined as strains differing by ≤12 SNPs. Risk factors for clustering were identified with multivariable analysis and then Bayesian models and TransPhylo were used to infer the timing of transmission within clusters. Of the 2277 culture-positive patients, 70.1% (1596/2277) were migrants: 72.1% (1043/1446) of the migrants patients developed TB within two years of arriving in Longhua; 38.8% within 6 months of arriving; and 12.3% (104/843) had TB symptoms when they arrived. Only 15.4% of Longhua strains were in genomic clusters. More than one third (33.6%) of patients were not treated in Shenzhen but were involved in nearly one third of the recent transmission events. Clustering was associated with migrants not treated in Shenzhen, males, and teachers/trainers. TB in Longhua is prinicipally due to reactivation of infections in migrants, but a proportion may have had clinical or incipient TB upon arrival in the district. Patients diagnosed but not treated in Longhua were involved in recent local TB transmission. Controlling TB in Shenzhen will require strategies to comprehensively diagnose and treat active TB in the internal migrant population.

Factors contributing to the high prevalence of multidrug-resistant tuberculosis: a study from China.

BACKGROUND: The rapid spread of multidrug-resistant tuberculosis (MDR-TB) has attracted global concerns. This study aimed to identify factors contributing to the high prevalence of MDR-TB in China's Heilongjiang province. METHODS: A cross-sectional survey following the WHO/International Union Against Tuberculosis and Lung Disease guidelines was conducted with consecutive recruitment of patients with TB in 30 counties selected at random in Heilongjiang in 2004. A total of 1995 patients were tested for MDR-TB. Factors associated with MDR-TB were identified through multilevel models and traditional logistic regression analysis, along with in-depth interviews with nine patients, five healthcare managers and four doctors. RESULTS: 241 patients (12%) were identified with MDR-TB. The retreatment patients were 5.48 times (95% CI 4.04 to 7.44) more likely to have MDR-TB than newly diagnosed patients. The patients who were treated with isoniazid and rifampin for >180 days were 4.82 times (95% CI 2.97 to 7.81) more likely to develop MDR-TB than those treated <180 days. Age and delay in initiating TB treatment were associated with MDR-TB. Financial burden, poor knowledge and side effects of TB treatment were perceived by the interviewees as influencing factors. Lack of coordination of services, unsatisfactory supervision of treatment and infection control jeopardised the control of MDR-TB. CONCLUSIONS: Inappropriate treatment is the most important influencing factor of MDR-TB. Increasing people's awareness of TB, early detection and appropriate treatment of patients with TB should become a priority, which requires strong commitment and collaboration among health organisations and greater compliance with TB treatment guidelines by service providers and patients.

Hydrogeochemical Characteristics and Water Quality Evaluation of Carboniferous Taiyuan Formation Limestone Water in Sulin Mining Area in Northern Anhui, China.

The Taiyuan formation limestone water in the Huaibei coalfield is not only the water source for coal mining, but also the water source for industry and agriculture in mining areas. Its hydrogeochemical characteristics and water quality are generally concerning. In this paper, conventional ion tests were carried out on the Taiyuan formation limestone water of 16 coal mines in the Sunan and Linhuan mining areas of the Huaibei coalfield. Piper trigram, Gibbs diagram and an ion scale coefficient map were used to analyze the hydrogeochemical characteristics of the Taiyuan formation limestone water. The water quality was evaluated in a fuzzy comprehensive manner. The results show that the main cation and anion contents in the Taiyuan formation limestone water were Na+ > Mg2+ > Ca2+ > K+, SO42- > HCO3- > Cl-. There were differences in the hydrogeochemical types of the Taiyuan formation limestone water in the two mining areas; HCO3-Na type water was dominant in the Sunan mining area and SO4·Cl-Na type water was dominant in the Linhuan mining area. The chemical composition of the Taiyuan formation limestone water is mainly affected by the weathering of the rock and is related to the dissolution of the evaporated salt and the weathering of the silicate. The fuzzy comprehensive evaluation results show that the V-type water accounts for a large proportion of the Taiyuan formation limestone water in the study area and the water quality is poor. This study provides a basis for the development and utilization of the Taiyuan formation limestone water and water environmental protection in the future.

[A rapid method based on advanced polymer chromatography for analyzing the products of the acid-catalyzed depolymerization of lignosulfonate].

In this study, a fast and efficient method for the separation and analysis of the products in the acid-catalyzed depolymerization of commercially available sodium lignosulfonate has been developed. The depolymerized lignosulfonate products were well separated and characterized by advanced polymer chromatography (APC) employing four ACQUITY APC XT columns in series and a ultraviolet detector. The developed method enabled the detection of relative-low-molecular-mass lignin degradation products with peak molecular weights (Mp) of 720, 490, and 260 Da, and an extremely low polydispersity index (PDI) of 1, indicating almost complete conversion of lignosulfonate to smaller molecules. The effects of reaction temperature, time, and catalyst/lignin ratio on the reaction products were systematically investigated. High yields of depolymerization (>80%) could be obtained under the mild acid-catalyzed conditions at 130℃ for 60 min using a catalyst/lignin ratio of 2.334:1. Preliminary studies also indicated that the mild acid-catalytic mechanism is unaffected by the reaction time, temperature, or catalyst concentration, thus suggesting the specificity of the catalytic procedure employed.

[Determination of the relative molecular mass distribution of the ultrafiltration fractionation product of lignosulfonate by advanced polymer chromatography].

The effects of testing conditions, such as pH and ionic strength of the mobile phase, on the relative molecular mass obtained by advanced polymer chromatography (APC) were investigated systematically. The non-size exclusion effects were discussed for lignosulfonate and its ultrafiltration fractionation product. The relative molecular mass distribution of lignosulfo-nate was well-characterized by an APC system using three columns in series, with a 10 µ L injection volume and 0.1 mol/L NaNO3 as the aqueous mobile phase, at a flow rate of 0.5 mL/min. The relative molecular mass distribution is in the eight molecular mass ranges. Optimized test conditions were used to characterize the ultrafiltration fractionation product of lignosulfonate. The obtained number average relative molecular masses (Mn) of the three components were 40410, 12208, and 1516 Da, indicating that lignosulfonate was well separated into three fractions by ultrafiltration membrane separation. The APC technique presented herein provides the basis for further application of the fractional separation products of lignosulfonate.

Attitudes Toward Bile Extraction From Living Bears: Survey of Citizens and Students in Beijing.

Bear bile is a traditional Chinese medicine that has been used for millennia. Several arguments support and oppose the use of bear farming in terms of conservation and nonhuman animal welfare. This study involved designing a questionnaire and surveying a random sample of general citizens and college students in Beijing to elicit their attitudes on bile extraction from living bears. Older people and people with lower education levels used more bear bile medicines. In total, 29.47% (n = 204) of citizens and 23.14% (n = 81) of students surveyed used bear bile medicine since 1990. Students were less willing to use bear bile medicines than citizens (p < .05). The level the respondents agreed with the blue side (against the extraction of bile from living bears; anti for short) was significantly higher than that for the red side (support the extraction of bile from living bears; pro for short; p < .05). Additionally, college students had a more distinct attitude toward the opposing views, which indicates they were more inclined to oppose bile extraction from living bears.

Conservation of Terrestrial Vertebrates in a Global Hotspot of Karst Area in Southwestern China.

The karst area of southwest China (KASC) is the largest piece of karst landscape on the earth and a global biodiversity hot-spot with high concentrations of endemic species. Although a number of nature reserves (NRs) have been established across the region, the representativeness of biodiversity of the NR system is still unknown. Based on comprehensive literature and field surveys, and intensive consultations with zoologists and wildlife managers, we compiled distributions of 1,204 terrestrial vertebrate species and 271 NRs in KASC. We found Jinxiu, Mengla, Hekou, and Jinghong have the richest amphibian species; Jinxiu has the highest species richness of reptiles; Jinghong, Menghai, and Mengla have the largest numbers of avian species; whereas, Mengla, Longzhou, and Ningming have the greatest mammalian diversity in the region. Gap analysis among NR system, species richness pattern, and five biogeographic indicators found insufficient representation of the NR system on territorial vertebrate diversity. The conservation effectiveness in Guizhou Province was much lower than that in Guangxi and Yunnan Provinces. Under-representation and over-representation simultaneously occurred in many of the ecoregions, elevation classes, vegetation types, landcover categories, and human disturbance intensity gradients. For conservation of terrestrial vertebrates in KASC, several suggestions were presented in this study.

Perception, Price and Preference: Consumption and Protection of Wild Animals Used in Traditional Medicine.

A wide array of wildlife species, including many animals, are used in traditional medicines across many medicinal systems, including in Traditional Chinese Medicine (TCM). Due to over-exploitation and habitat loss, the populations of many animals commonly used in TCM have declined and are unable to meet market demand. A number of measures have been taken to try to reduce the impact that this large and growing market for TCM may have on wild animal species. Consumer preferences and behavior are known to play an important role in the consumption and protection of wild animals used in traditional medicine, and thus are likely to be an important factor in the success of many of these mechanisms--particularly given the significant percentage of TCMs that are over-the-counter products (access to which is not mediated by practitioners). In this study we conducted questionnaires and designed stated preference experiments embodying different simulation scenarios using a random sample of the population in Beijing to elicit individuals' knowledge, perceptions and preferences toward wild or farmed animal materials and their substitutes used in traditional Chinese medicine. We found that respondents had a stated preference for wild materials over farm-raised and other alternatives because they believe that the effectiveness of wild-sourced materials is more credible than that of other sources. However, we also found that, although respondents used TCM products, they had a poor understanding of the function or composition of either traditional Chinese medicines or proprietary Chinese medicines (PCM), and paid little attention to the composition of products when making purchasing decisions. Furthermore, awareness of the need for species protection, or "conservation consciousness" was found to play an important role in willingness to accept substitutions for wild animal materials, while traditional animal medicinal materials (TAMs) derived from well-known endangered species, such as bear bile and tiger bone, show relatively higher substitutability. These results suggest that there is still hope for conservation measures which seek to promote a transition to farmed animal, plant and synthetic ingredients and provide clear directions for future social marketing, education and engagement efforts.

[Relative molecular mass determination of phenolated depolymerized sodium lignosulfonate by advanced polymer chromatography system].

Advanced polymer chromatography (APC) is a newly developed high resolution polymer characterization technique. Within 10 min, it can separate polymers with high resolution and obtain the average relative molecular mass distribution parameters of the polymers. The Mr distribution of the depolymerized lignin product was well characterized with low relative standard deviation (RSD less than 1%) by APC system using ACQUITY AQ 450 Å, 200 Å, and 45 Å columns in series, with 10 µL injection volume, and weak alkaline phosphate buffer solution as the aqueous mobile phase at a flow rate of 0.5 mL/min. Compared with traditional gel permeation chromatography (GPC), the APC system had the advantages of high sensitivity and good reproducibility. The technique to determine the average relative molecular mass distribution of depolymerized lignin oligomers in aqueous phase described in this paper will pave the way for new methods to separate and analyze high performance natural materials, and the feasible method for the investigation of the mechanism of depolymerization and the regulation for liquefied lignin would also be established.

Raman and terahertz spectroscopical investigation of cocrystal formation process of piracetam and 3-hydroxybenzoic acid.

Cocrystallization can improve physical and chemical properties of active pharmaceutical ingredient, and this feature has great potential in pharmaceutical development. In this study, the cocrystal of piracetam and 3-hydroxybenzoic acid under grinding condition has been characterized by Raman and terahertz spectroscopical techniques. The major vibrational modes of individual starting components and cocrystal are obtained and assigned. Spectral results show that the vibrational modes of the cocrystal are different from those of the corresponding parent materials. The dynamic process of such pharmaceutical cocrystal formation has also been monitored directly with Raman and THz spectra. The formation rate is pretty fast in first several 20 min grinding time, and then it becomes slow. After ∼35 min, such process has been almost completed. These results offer us the unique means and benchmark for characterizing the cocrystal conformation from molecule-level and also provide us rich information about the reaction dynamic during cocrystal formation process in pharmaceutical fields.

Vibrational spectroscopic study of polymorphism and polymorphic transformation of the anti-viral drug lamivudine.

Vibrational spectra of hydrated and anhydrous lamivudines, and also the dynamic process of polymorphic transformation have been characterized by Fourier transform infrared (FT-IR) and Raman spectroscopic techniques. The vibrational modes of both polymorphic lamivudines are assigned. FT-IR and Raman spectral results show that the interaction between crystalline water and lamivudine molecular has an important effect on the molecular vibration motions of polymorphic lamivudines. The two characteristic Raman peaks at 783 and 798 cm(-1) represent hydrated and anhydrous lamivudine respectively. The relationship between changes of two characteristic peak normalized areas and heating time could be fitted with single exponential functions, and the dynamic information of polymorphic transformation of lamivudine drug is obtained. The decay rate of characteristic peak for hydrated lamivudine and the growth rate of that for anhydrous lamivudine are consistent during dehydration transformation process. The reported results provide us important benchmark for qualitatively monitoring different polymorphic drugs and also establishing the corresponding model for the polymorphic transformation of drugs in related pharmaceutical research fields.

A spatially explicit model of functional connectivity for the endangered Przewalski's gazelle (Procapra przewalskii) in a patchy landscape.

BACKGROUND: Habitat fragmentation, associated with human population expansion, impedes dispersal, reduces gene flow and aggravates inbreeding in species on the brink of extinction. Both scientific and conservation communities increasingly realize that maintaining and restoring landscape connectivity is of vital importance in biodiversity conservation. Prior to any conservation initiatives, it is helpful to present conservation practitioners with a spatially explicit model of functional connectivity for the target species or landscape. METHODOLOGY/PRINCIPAL FINDINGS: Using Przewalski's gazelle (Procapra przewalskii) as a model of endangered ungulate species in highly fragmented landscape, we present a model providing spatially explicit information to inform the long-term preservation of well-connected metapopulations. We employed a Geographic Information System (GIS) and expert-literature method to create a habitat suitability map, to identify potential habitats and to delineate a functional connectivity network (least-cost movement corridors and paths) for the gazelle. Results indicated that there were limited suitable habitats for the gazelle, mainly found to the north and northwest of the Qinghai Lake where four of five potential habitat patches were identified. Fifteen pairs of least-cost corridors and paths were mapped connecting eleven extant populations and two neighboring potential patches. The least-cost paths ranged from 0.2 km to 26.8 km in length (averaging 12.4 km) and were all longer than corresponding Euclidean distances. CONCLUSIONS/SIGNIFICANCE: The model outputs were validated and supported by the latest findings in landscape genetics of the species, and may provide impetus for connectivity conservation programs. Dispersal barriers were examined and appropriate mitigation strategies were suggested. This study provides conservation practitioners with thorough and visualized information to reserve the landscape connectivity for Przewalski's gazelle. In a general sense, we proposed a heuristic framework for species with similar biological and ecological characteristics.

Effects of reproductive status, social rank, sex and group size on vigilance patterns in Przewalski's gazelle.

BACKGROUND: Quantifying vigilance and exploring the underlying mechanisms has been the subject of numerous studies. Less attention has focused on the complex interplay between contributing factors such as reproductive status, social rank, sex and group size. Reproductive status and social rank are of particular interest due to their association with mating behavior. Mating activities in rutting season may interfere with typical patterns of vigilance and possibly interact with social rank. In addition, balancing the tradeoff between vigilance and life maintenance may represent a challenge for gregarious ungulate species rutting under harsh winter conditions. We studied vigilance patterns in the endangered Przewalski's gazelle (Procapra przewalskii) during both the rutting and non-rutting seasons to examine these issues. METHODOLOGY/PRINCIPAL FINDINGS: Field observations were carried out with focal sampling during rutting and non-rutting season in 2008-2009. Results indicated a complex interplay between reproductive status, social rank, sex and group size in determining vigilance in this species. Vigilance decreased with group size in female but not in male gazelles. Males scanned more frequently and thus spent more time vigilant than females. Compared to non-rutting season, gazelles increased time spent scanning at the expense of bedding in rutting season. During the rutting season, territorial males spent a large proportion of time on rutting activities and were less vigilant than non-territorial males. Although territorial males may share collective risk detection with harem females, we suggest that they are probably more vulnerable to predation because they seemed reluctant to leave rut stands under threats. CONCLUSIONS/SIGNIFICANCE: Vigilance behavior in Przewalski's gazelle was significantly affected by reproductive status, social rank, sex, group size and their complex interactions. These findings shed light on the mechanisms underlying vigilance patterns and the tradeoff between vigilance and other crucial activities.

Environmental effects on vertebrate species richness: testing the energy, environmental stability and habitat heterogeneity hypotheses.

BACKGROUND: Explaining species richness patterns is a central issue in biogeography and macroecology. Several hypotheses have been proposed to explain the mechanisms driving biodiversity patterns, but the causes of species richness gradients remain unclear. In this study, we aimed to explain the impacts of energy, environmental stability, and habitat heterogeneity factors on variation of vertebrate species richness (VSR), based on the VSR pattern in China, so as to test the energy hypothesis, the environmental stability hypothesis, and the habitat heterogeneity hypothesis. METHODOLOGY/PRINCIPAL FINDINGS: A dataset was compiled containing the distributions of 2,665 vertebrate species and eleven ecogeographic predictive variables in China. We grouped these variables into categories of energy, environmental stability, and habitat heterogeneity and transformed the data into 100 × 100 km quadrat systems. To test the three hypotheses, AIC-based model selection was carried out between VSR and the variables in each group and correlation analyses were conducted. There was a decreasing VSR gradient from the southeast to the northwest of China. Our results showed that energy explained 67.6% of the VSR variation, with the annual mean temperature as the main factor, which was followed by annual precipitation and NDVI. Environmental stability factors explained 69.1% of the VSR variation and both temperature annual range and precipitation seasonality had important contributions. By contrast, habitat heterogeneity variables explained only 26.3% of the VSR variation. Significantly positive correlations were detected among VSR, annual mean temperature, annual precipitation, and NDVI, whereas the relationship of VSR and temperature annual range was strongly negative. In addition, other variables showed moderate or ambiguous relations to VSR. CONCLUSIONS/SIGNIFICANCE: The energy hypothesis and the environmental stability hypothesis were supported, whereas little support was found for the habitat heterogeneity hypothesis.

Effect of anthropogenic landscape features on population genetic differentiation of Przewalski's gazelle: main role of human settlement.

Anthropogenic landscapes influence evolutionary processes such as population genetic differentiation, however, not every type of landscape features exert the same effect on a species, hence it is necessary to estimate their relative effect for species management and conservation. Przewalski's gazelle (Procapra przewalskii), which inhabits a human-altered area on Qinghai-Tibet Plateau, is one of the most endangered antelope species in the world. Here, we report a landscape genetic study on Przewalski's gazelle. We used skin and fecal samples of 169 wild gazelles collected from nine populations and thirteen microsatellite markers to assess the genetic effect of anthropogenic landscape features on this species. For comparison, the genetic effect of geographical distance and topography were also evaluated. We found significant genetic differentiation, six genetic groups and restricted dispersal pattern in Przewalski's gazelle. Topography, human settlement and road appear to be responsible for observed genetic differentiation as they were significantly correlated with both genetic distance measures [F(ST)/(1-F(ST)) and F'(ST)/(1-F'(ST))] in Mantel tests. IBD (isolation by distance) was also inferred as a significant factor in Mantel tests when genetic distance was measured as F(ST)/(1-F(ST)). However, using partial Mantel tests, AIC(c) calculations, causal modeling and AMOVA analysis, we found that human settlement was the main factor shaping current genetic differentiation among those tested. Altogether, our results reveal the relative influence of geographical distance, topography and three anthropogenic landscape-type on population genetic differentiation of Przewalski's gazelle and provide useful information for conservation measures on this endangered species.