Landscape pattern is a widely used concept for the demonstration of landscape characteristic features. The integral spatial distribution trend of landscape elements is interested point in the landscape ecological rese...Landscape pattern is a widely used concept for the demonstration of landscape characteristic features. The integral spatial distribution trend of landscape elements is interested point in the landscape ecological research, especially in those of complex secondary forest regions with confusing mosaics of land cover. Trend surface analysis which used in community and population ecological researches was introduced to reveal the landscape pattern. A reasonable and reliable approach for application of trend surface analysis was provided in detail. As key steps of the approach, uniform grid point sampling method was developed. The efforts were also concentrated at an example of Guandishan forested landscape. Some basic rules of spatial distribution of landscape elements were exclaimed. These will be benefit to the further study in the area to enhance the forest sustainable management and landscape planning.展开更多
In this paper, first, based on landscape ecology theories, we respectively selected indexes from 4 aspects, area, edge, shape, and density, of the landscape type to describe the status of forest landscape patterns, an...In this paper, first, based on landscape ecology theories, we respectively selected indexes from 4 aspects, area, edge, shape, and density, of the landscape type to describe the status of forest landscape patterns, and we established the stability index of landscape pattern (LSBI). Then, based on geo-statistical theories, we divided the forest in the reservoir area into 3990 grids of 4 km × 4 km using network technology and employing ordinary Kriging modelling to make trend surface analyses of the forest resources in the reservoir area. Finally, based on statistics principles, we used sampling theory to systematically extract 227 samples to obtain 7 periods of remote-sensing data from 1990a to 2012a. Then, we classified and extracted the forest in the sampling area using remote sensing, and we analysed each result with an Autoregressive Integrated Moving Average Model (ARIMA) time-series model. The results indicated the following: 1) the landscape structure of the reservoir area was primarily needle-leaved forest, broad-leaved forest and bush forest, and the mixed stands and bamboo stands were secondary;2) the difference of the forest landscape pattern stability in the reservoir area, in all directions, was not significant, but the southern region was slightly more stable;and 3) the stability of the forest landscape pattern in the reservoir area increased from 1990a to 2012a. It kept increasing until 2016a. This study provides a theoretical basis for the reasonable management and decisions about the forest resources in the Three Gorges Reservoir Area. Meanwhile, it also explores methods for relevant research and has practical significance.展开更多
Background: Salivary gland tumours (SGTs) are rare, but recent reports suggest an increasing incidence. Although there are previous Nigerian studies on the patterns of SGTs, patterns and trends of disease may change o...Background: Salivary gland tumours (SGTs) are rare, but recent reports suggest an increasing incidence. Although there are previous Nigerian studies on the patterns of SGTs, patterns and trends of disease may change over time. The aim of this study was to describe the pattern of presentation of SGTs, and to determine the trends in occurrence of SGTs at Federal Teaching Hospital (FTH), Gombe over a period of 15 years. Method: This descriptive study included cases of histologically diagnosed SGTs from January 2008 to December 2022. Relevant information (age, gender, site, year of diagnosis, and histopathologic diagnosis) was extracted from the cancer registers and histopathologic records. The lesions were then categorized into benign and malignant SGTs and grouped into three groups spanning 5 years each based on the year of diagnosis. Data analysis was done using IBM SPSS version 23, and p ≤ 0.05 was considered statistically significant. Results: There were 93 (61.2%) benign and 59 (38.8%) malignant SGTs. Benign SGTs had a mean age of 36.4 ± 13.6 years, and were more common in females (57.0%), and in the parotid (41.9%). Pleomorphic adenoma (94.6%) was the most common benign SGT. Malignant SGTs had a mean age of 44.5 ± 18.4 years, with male predilection (54.2%) and occurrence mostly in the palate (27.6%) and parotid (22.4%). Mucoepidermoid carcinoma (39.0%) and adenoid cystic carcinoma (32.2%) were the most frequent malignant SGTs. The mean age of occurrence of malignant SGTs was significantly higher than that of benign SGTs (p = 0.005). The trend analysis showed that there has been a steady rise in the proportion of males presenting with malignant SGTs. Similarly, there has been a steady increase in the frequency of benign SGTs in the parotid. The palate was the predominant site for the malignant SGTs between 2008 and 2012, but in the last five years (2018 to 2022), the parotid has become the predominant site. Over the duration of the study, the ratio of benign to malignant SGTs has remained relatively constant. Conclusion: While the overall pattern of presentation of SGTs in Gombe is similar to reports in the literature, this study has identified some changes in trends over the years.展开更多
文摘Landscape pattern is a widely used concept for the demonstration of landscape characteristic features. The integral spatial distribution trend of landscape elements is interested point in the landscape ecological research, especially in those of complex secondary forest regions with confusing mosaics of land cover. Trend surface analysis which used in community and population ecological researches was introduced to reveal the landscape pattern. A reasonable and reliable approach for application of trend surface analysis was provided in detail. As key steps of the approach, uniform grid point sampling method was developed. The efforts were also concentrated at an example of Guandishan forested landscape. Some basic rules of spatial distribution of landscape elements were exclaimed. These will be benefit to the further study in the area to enhance the forest sustainable management and landscape planning.
文摘In this paper, first, based on landscape ecology theories, we respectively selected indexes from 4 aspects, area, edge, shape, and density, of the landscape type to describe the status of forest landscape patterns, and we established the stability index of landscape pattern (LSBI). Then, based on geo-statistical theories, we divided the forest in the reservoir area into 3990 grids of 4 km × 4 km using network technology and employing ordinary Kriging modelling to make trend surface analyses of the forest resources in the reservoir area. Finally, based on statistics principles, we used sampling theory to systematically extract 227 samples to obtain 7 periods of remote-sensing data from 1990a to 2012a. Then, we classified and extracted the forest in the sampling area using remote sensing, and we analysed each result with an Autoregressive Integrated Moving Average Model (ARIMA) time-series model. The results indicated the following: 1) the landscape structure of the reservoir area was primarily needle-leaved forest, broad-leaved forest and bush forest, and the mixed stands and bamboo stands were secondary;2) the difference of the forest landscape pattern stability in the reservoir area, in all directions, was not significant, but the southern region was slightly more stable;and 3) the stability of the forest landscape pattern in the reservoir area increased from 1990a to 2012a. It kept increasing until 2016a. This study provides a theoretical basis for the reasonable management and decisions about the forest resources in the Three Gorges Reservoir Area. Meanwhile, it also explores methods for relevant research and has practical significance.
文摘Background: Salivary gland tumours (SGTs) are rare, but recent reports suggest an increasing incidence. Although there are previous Nigerian studies on the patterns of SGTs, patterns and trends of disease may change over time. The aim of this study was to describe the pattern of presentation of SGTs, and to determine the trends in occurrence of SGTs at Federal Teaching Hospital (FTH), Gombe over a period of 15 years. Method: This descriptive study included cases of histologically diagnosed SGTs from January 2008 to December 2022. Relevant information (age, gender, site, year of diagnosis, and histopathologic diagnosis) was extracted from the cancer registers and histopathologic records. The lesions were then categorized into benign and malignant SGTs and grouped into three groups spanning 5 years each based on the year of diagnosis. Data analysis was done using IBM SPSS version 23, and p ≤ 0.05 was considered statistically significant. Results: There were 93 (61.2%) benign and 59 (38.8%) malignant SGTs. Benign SGTs had a mean age of 36.4 ± 13.6 years, and were more common in females (57.0%), and in the parotid (41.9%). Pleomorphic adenoma (94.6%) was the most common benign SGT. Malignant SGTs had a mean age of 44.5 ± 18.4 years, with male predilection (54.2%) and occurrence mostly in the palate (27.6%) and parotid (22.4%). Mucoepidermoid carcinoma (39.0%) and adenoid cystic carcinoma (32.2%) were the most frequent malignant SGTs. The mean age of occurrence of malignant SGTs was significantly higher than that of benign SGTs (p = 0.005). The trend analysis showed that there has been a steady rise in the proportion of males presenting with malignant SGTs. Similarly, there has been a steady increase in the frequency of benign SGTs in the parotid. The palate was the predominant site for the malignant SGTs between 2008 and 2012, but in the last five years (2018 to 2022), the parotid has become the predominant site. Over the duration of the study, the ratio of benign to malignant SGTs has remained relatively constant. Conclusion: While the overall pattern of presentation of SGTs in Gombe is similar to reports in the literature, this study has identified some changes in trends over the years.
