Bibliometric analysis of studies of the Arctic and Antarctic polynya.

Based on the polar polynya-related 1,677 publications derived from the Web of Science from 1980 to 2021, this study analyses the scientific performance of polar polynya research with respect to publication outputs, scientific categories, journals, productive countries and partnerships, co-cited references, bibliographic documents and the thermal trends of keywords. The number of publications and citations on polar polynya has increased 17.28 and 11.22% annually since the 1990s, respectively, and those numbers for Antarctic polynya have surpassed that of the Arctic polynya since 2014. Oceanography, geosciences multidisciplinary, and environmental sciences were the top 3 scientific categories in the Arctic and Antarctic polynya research field. Nevertheless, ecology and meteorology are gaining ground in the Arctic and the Antarctic recently. The Journal of Geophysical Research-Oceans accommodated most publications for both polar regions, followed by Deep-Sea Research Part II-Topical Studies in Oceanography and Polar Biology. The Continental Shelf Research and Ocean Modeling were favored journals in Arctic and Antarctic polynya research, respectively. The USA dominated the polar polynya study field with 31.74%/43.60% publications on the Arctic/Antarctic polynya research, followed by Canada (40.23%/4.32%) and Germany (17.21%/11.22%). Besides, Australia occupied the second most popular position in the Antarctic polynya research. The keywords analysis concluded that the polynya topics that generated the most interest were altered from model to climate change in the Arctic and ocean water and glacier in the Antarctic over time. This study gives a summary of the polar polynya scientific field through bibliometric analysis which may provide reference for future research.

Aerial photography based census of Adélie Penguin and its application in CH4 and N2O budget estimation in Victoria Land, Antarctic.

Penguin guano provides favorable conditions for production and emission of greenhouse gases (GHGs). Many studies have been conducted to determine the GHG fluxes from penguin colonies, however, at regional scale, there is still no accurate estimation of total GHG emissions. We used object-based image analysis (OBIA) method to estimate the Adélie penguin (Pygoscelis adeliae) population based on aerial photography data. A model was developed to estimate total GHG emission potential from Adélie penguin colonies during breeding seasons in 1983 and 2012, respectively. Results indicated that OBIA method was effective for extracting penguin information from aerial photographs. There were 17,120 and 21,183 Adélie penguin breeding pairs on Inexpressible Island in 1983 and 2012, respectively, with overall accuracy of the estimation of 76.8%. The main reasons for the increase in Adélie penguin populations were attributed to increase in temperature, sea ice and phytoplankton. The average estimated CH4 and N2O emissions tended to be increasing during the period from 1983 to 2012 and CH4 was the main GHG emitted from penguin colonies. Total global warming potential (GWP) of CH4 and N2O emissions was 5303 kg CO2-eq in 1983 and 6561 kg CO2-eq in 2012, respectively.

Effect of inhibin gene immunization on antibody production and reproductive performance in Partridge Shank hens.

To investigate the effect of inhibin gene immunization on antibody production and reproductive performance in broiler breeder females, Partridge Shank hens aged 380 days were immunized with inhibin recombinant plasmid pcISI. One hundred and twenty hens were randomly assigned to four groups and treated intramuscularly with 25, 75, or 125 µg/300-µL inhibin recombinant plasmid pcISI (T1∼T3) or 300-µL saline as control (C), respectively. Booster immunization was given with the same dosage 20 days later. Blood and egg samples were collected to detect the antibody against inhibin by enzyme-linked immunosorbent assay and to evaluate egg performance. The ovaries were collected to classify the follicles and detect the FSH receptor (FSHR) messenger RNA (mRNA) expression by reverse transcription-PCR. The results showed that immunization against pcISI could elicit antibody against inhibin in both plasma and egg yolk compared with the control (P < 0.05), whereas booster immunization did not increase the antibody level in plasma. Vaccination promoted egg lay during the first 30 days after primary vaccination (P < 0.05) with no effect on egg quality and hatching rate. Immunization increased the amounts of dominant, small yellow and large white follicles in the ovary (P < 0.05). Reverse transcription-PCR results showed that immunization increased the FSHR mRNA in the large white follicles, whereas decreased the FSHR mRNA in the small yellow follicles (P < 0.05). In conclusion, inhibin vaccine pcISI can stimulate the production of antibody against inhibin as well as the follicle development and egg laying performance in Partridge Shank hens, which provides a good foundation for the application of inhibin DNA vaccine in avian production.

Ocean-driven thinning enhances iceberg calving and retreat of Antarctic ice shelves.

Iceberg calving from all Antarctic ice shelves has never been directly measured, despite playing a crucial role in ice sheet mass balance. Rapid changes to iceberg calving naturally arise from the sporadic detachment of large tabular bergs but can also be triggered by climate forcing. Here we provide a direct empirical estimate of mass loss due to iceberg calving and melting from Antarctic ice shelves. We find that between 2005 and 2011, the total mass loss due to iceberg calving of 755 ± 24 gigatonnes per year (Gt/y) is only half the total loss due to basal melt of 1516 ± 106 Gt/y. However, we observe widespread retreat of ice shelves that are currently thinning. Net mass loss due to iceberg calving for these ice shelves (302 ± 27 Gt/y) is comparable in magnitude to net mass loss due to basal melt (312 ± 14 Gt/y). Moreover, we find that iceberg calving from these decaying ice shelves is dominated by frequent calving events, which are distinct from the less frequent detachment of isolated tabular icebergs associated with ice shelves in neutral or positive mass balance regimes. Our results suggest that thinning associated with ocean-driven increased basal melt can trigger increased iceberg calving, implying that iceberg calving may play an overlooked role in the demise of shrinking ice shelves, and is more sensitive to ocean forcing than expected from steady state calving estimates.

Cell-specific expression and immunolocalization of nitric oxide synthase isoforms and soluble guanylyl cyclase α1 and ß1 subunits in the ovary of fetal, neonatal and immature pigs.

The present study is designed to investigate the cellular expression and immunolocalization of three different nitric oxide synthase (NOS) isoforms and soluble guanylyl cyclase (sGC) subunits in the porcine ovary. Our results showed that in the fetal and neonatal pigs, all three isoforms of NOS were mainly localized in the oocyte and showed the expression of gradual increase in the granulosa cell and theca cell with the growing follicle. In addition, subunits of the sGC, sGC α1 and ß1 were mainly expressed in the granulosa cell in precious studies. The bioactivity of total NOS, eNOS, iNOS and nNOS was detected in the ovary and were higher at prenatal stages compared to postnatal stages. However, the activities of nNOS were no different between prenatal stages and postnatal stages. Taken together, our findings suggested that the NOS/sGC pathway may be involved in the follicular formation and development in the porcine ovary.

Spatio-temporal distribution of malaria in Yunnan Province, China.

The spatio-temporal distribution pattern of malaria in Yunnan Province, China was studied using a geographic information system technique. Both descriptive and temporal scan statistics revealed seasonal fluctuation in malaria incidences in Yunnan Province with only one peak during 1995-2000, and two apparent peaks from 2001 to 2005. Spatial autocorrelation analysis indicated that malaria incidence was not randomly distributed in the province. Further analysis using spatial scan statistics discovered that the high risk areas were mainly clustered at the bordering areas with Myanmar and Laos, and in Yuanjiang River Basin. There were obvious associations between Plasmodium vivax and Plasmodoium falciparum malaria incidences and climatic factors with a clear 1-month lagged effect, especially in cluster areas. All these could provide information on where and when malaria prevention and control measures would be applied. These findings imply that countermeasures should target high risk areas at suitable times, when climatic factors facilitate the transmission of malaria.

Predicting the risk of hantavirus infection in Beijing, People's Republic of China.

To understand the spatial distribution of hantavirus infections across landscapes and its influencing environment factors in Beijing, People's Republic of China, rodents captured in this region were examined for hantavirus by reverse transcription-polymerase chain reaction. A total of 1,639 rodents were trapped at 86 randomly selected sites. The overall infection rate for hantavirus was 7.14% in the rodents. Multivariate logistic regression analysis indicated that the natural infection rates for hantavirus in rodents were significantly associated with rice agriculture (odds ratio [OR] = 2.88, 95% confidence interval [CI] = 1.27-30.70), orchards (OR = 1.12, 95% CI = 1.02-5.96), and moderate elevation (OR = 9.83, 95% CI = 2.22-43.55). A risk map was constructed on the basis of these significant factors to predict extension and transmission of infection with hantavirus in this region.

Spatial analysis of malaria in Anhui province, China.

BACKGROUND: Malaria has re-emerged in Anhui Province, China, and this province was the most seriously affected by malaria during 2005-2006. It is necessary to understand the spatial distribution of malaria cases and to identify highly endemic areas for future public health planning and resource allocation in Anhui Province. METHODS: The annual average incidence at the county level was calculated using malaria cases reported between 2000 and 2006 in Anhui Province. GIS-based spatial analyses were conducted to detect spatial distribution and clustering of malaria incidence at the county level. RESULTS: The spatial distribution of malaria cases in Anhui Province from 2000 to 2006 was mapped at the county level to show crude incidence, excess hazard and spatial smoothed incidence. Spatial cluster analysis suggested 10 and 24 counties were at increased risk for malaria (P < 0.001) with the maximum spatial cluster sizes at < 50% and < 25% of the total population, respectively. CONCLUSION: The application of GIS, together with spatial statistical techniques, provide a means to quantify explicit malaria risks and to further identify environmental factors responsible for the re-emerged malaria risks. Future public health planning and resource allocation in Anhui Province should be focused on the maximum spatial cluster region.