Different approaches for modeling grouped survival data: A mango tree study     

Suely Ruiz Giolo  Enrico Antonio Colosimo  Clarice Garcia Borges Demétrio 《Journal of Agricultural, Biological & Environmental Statistics》2009,14(2):154-169

Interval-censored survival data, in which the event of interest is not observed exactly but is only known to occur within some time interval, occur very frequently. In some situations, event times might be censored into different, possibly overlapping intervals of variable widths; however, in other situations, information is available for all units at the same observed visit time. In the latter cases, interval-censored data are termed grouped survival data. Here we present alternative approaches for analyzing intervalcensored data. We illustrate these techniques using a survival data set involving mango tree lifetimes. This study is an example of grouped survival data.  相似文献   

Numerical and behavioral responses of waterfowl to the invasive American mink: A conservation paradox     

Marcin Brzeziński  Magdalena Natorff  Andrzej Zalewski  Michał Żmihorski 《Biological conservation》2012,147(1):68-78

A behavioral response is usually the first adaptation of animals to environmental changes such as the introduction of an alien invasive species, and it seems to be the most important factor in reducing the negative impact of new predators on naive prey. This study examined changes in the abundance and behavior of breeding coots (Fulica atra) and great crested grebes (Podiceps cristatus) in response to invasion of the Mazurian Lakeland (NE Poland) by American mink (Neovison vison), first recorded here in 1984. Feral mink densities varied from 1.0 to 14.6 individuals per 10 km of shoreline. Mink were responsible for the losses of 17–58% of experimental clutches (artificial nests containing chicken eggs) that were deployed. Mink destroyed more experimental clutches than other predators; the effects of mink predation were similar in reeds and on the bank. Radio-tracking showed that mink avoided lake banks near human settlements. Mink have markedly affected the breeding distribution of both species and caused a greater than 20-fold decline in coot numbers. For coots and grebes breeding distribution and nesting success were positively associated with built-up areas along lake shores and also with whether the birds were breeding in colonies. Increased brood survival of coots and grebes near human settlements is a paradox in the sense that a man-made habitat change has provided refuge from an alien predator.  相似文献   

The importance of the gravel excavation industry for the conservation of grassland butterflies     

Magdalena Lenda  Piotr Skórka  Dawid Moroń  Zuzanna M. Rosin  Piotr Tryjanowski 《Biological conservation》2012,148(1):180-190

Conservation biology often relies on the protection of (semi)natural habitat remnants. However, the ever increasing human population is taking over natural resources and habitats. Here, contrary to most other studies, we ask how human-associated severe changes in the environment can be used to enrich local biodiversity. We tested if industrial activity (gravel excavation) leads to the creation of habitats that support grassland butterflies and how these areas add to the richness of local species when compared to typical semi-natural habitats (grasslands). We also identified key factors affecting the richness, abundance, diversity and commonness of butterfly species to provide practical recommendations. Species richness, diversity index and the occurrence of rare species were higher in gravel-pit shores than in grasslands. The richness of butterfly species and their abundance were positively affected by the richness of plant species, shrub density and age of the gravel-pit but negatively by the cover of water reservoirs in the surrounding area and the isolation of gravel-pits from grasslands. Butterfly diversity was positively influenced by the richness of plant species and proximity of human settlement but negatively by area of the shore and isolation. Our study is the first one to show the high value of gravel-pits for the conservation of butterflies. We recommend the inclusion of gravel-pits in a system of ecological networks and management of their surroundings to improve the colonization rate of rare species. We suggests that directing interest to the possible positive effects of industrial development on biodiversity may support conservation efforts.  相似文献   

THE IMPACT OF ORGANIC AMENDMENTS ON FOREST SOIL PROPERTIES UNDER MEDITERRANEAN CLIMATIC CONDITIONS     

Paloma Hueso‐Gonzlez  Juan Francisco Martínez‐Murillo  Jose Damin Ruiz‐Sinoga 《Land Degradation \u0026amp; Development》2014,25(6):604-612

Restoring the native vegetation is one of the most effective ways to control soil degradation in Mediterranean areas, especially in very degraded areas. In the initial months after afforestation, vegetation cover establishment and soil quality could be better sustained if the soil was amended with an external extra source of organic matter. The goal of this study was to test the effect of various organic amendments on select soil properties [soil organic carbon (SOC), pH, and electrical conductivity (EC)] over a 24‐month period. Four amendments were applied in an experimental set of plots: straw mulching (SM), mulch with chipped branches of Aleppo Pine (Pinus halepensis L.; PM), sheep manure compost (SH), and sewage sludge (RU). Plots were afforested following the same spatial pattern, and amendments were mixed with the soil at the rate 10 Mg ha⁻¹. Organic amendments helped maintain SOC over the initial 6 months after the afforestation. However, only the SM and PM treatments had increased SOC values after 24 months. Decreases in EC were found after the addition of SM, PM, and SH amendments. However, RU increased EC values 24 months after the afforestation. Variations in pH values were not sufficient to establish differences among the various treatments. Furthermore, the results show that forest soils with or without organic amendments responded similarly to the seasonal changes in Mediterranean conditions. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Effect of soil pollution with polycyclic aromatic hydrocarbons on the properties of humic acids     

Magdalena Banach-Szott  Bożena Debska  Ewa Rosa 《Journal of Soils and Sediments》2014,14(6):1169-1178

Purpose

Interestingly, soil is the component of the natural environment in which most hydrophobic organic pollution including polycyclic aromatic hydrocarbons (PAHs) gets accumulated. The aim of the present paper was to determine the effect of soil pollution with PAHs on the elemental composition, spectral properties, and hydrophobic and hydrophilic properties of humic acids. The research was performed on different types of soil samples that were artificially polluted with selected PAHs (anthracene, pyrene, fluorene and chrysene).

Materials and methods

The soil samples were polluted with selected PAHs in an amount corresponding to 10 mg PAHs kg^?1. The PAHs-polluted soil samples were incubated for 180 and 360 days at a temperature of 20–25 °C and fixed moisture (50 % of field water capacity). Humic acids (HAs) were extracted from the soil samples prior to the incubation (additionally, soils not polluted with PAHs) and after 180 and 360 days of incubation. For isolated HAs, the following analyses were performed: elemental composition, UV–Vis and IR spectra, susceptibility to oxidation, and hydrophilic (HIL) and hydrophobic (HOB) properties were determined using high-performance liquid chromatography.

Results and discussion

The research demonstrated that introducing anthracene, fluorene, pyrene and chrysene to soil samples resulted in a change in some of the quality parameters of humic acids. However, the intensity and the direction of those changes were determined by soil properties. The changes of the parameters, once PAHs were introduced, that did not depend on the soil properties were ΔA _665u and ΔA _465u (susceptibility to oxidation at wavelengths of 465 and 665 nm) as well as HIL/ΣHOB. The same tendency in changes in the structure of humic acids, once PAHs were introduced, was also observed based on the Fourier transform infrared spectra pattern.

Conclusions

A single pollution of soils with PAHs that leads to changes in the quality parameters of humic acids shows that, as for the soils permanently exposed to pollution with those compounds, significant changes can occur in the properties of humic acids. As a result, it can lead to a change in the functions played by humic acids in the environment.  相似文献   

Historical morphogenesis of the Turia River coastal flood plain in the Mediterranean littoral of Spain     

P. Carmona  J.M. Ruiz 《CATENA》2011

The cross-referencing of sedimentological, stratigraphic, geoarchaeological and radiocarbon data enables us to establish the geomorphologic evolution of the Late Holocene coastal flood plain of the Turia River. The Holocene marine transgression formed a coastal barrier lagoon environment in the coastal plain. During the Late Holocene, increased sediments supplied to the low reach of the river promoted: (a): the progradation of deltaic coastal sandy ridges on the coastline and (b): the aggradation of the floodplain on top of the sedimentary sequence. Four phases are clearly recognised in the geoarchaeological record of the flood plain. (1): High magnitude flooding events (2800 BP to 3rd century BC). (2): Slow riverbed aggradation and progressive levee formation (low energy flood regime) in Roman times (2nd century BC to 5th century AD). (3): Swampy environmental processes (6th to 9th centuries). (4): Second high-magnitude flooding phase (11th century). The navigable channel of the Roman and early Islamic periods became a wide and shallow braided channel in Medieval times. These phases are correlated with others detected by researchers in many areas of the Mediterranean region and with global Holocene climate events.  相似文献   

Epizotiology and phylogeny of equine arteritis virus in hucul horses     

Rola J  Larska M  Rola JG  Belák S  Autorino GL 《Veterinary microbiology》2011,148(2-4):402-407

The aim of the study was to determine the situation of equine arteritis virus (EAV) infections in hucul horses. A total of 176 horses (154 mares and 22 stallions) from the biggest hucul horse stud in Poland were tested. Antibodies against EAV were detected in 97 (55.1%) horses. The EAV seroprevalence among mares was 53.2% while in stallions - 68.2%. The percentage of positive mares increased with their age, thus amongst the mares of less than 2 years of age the percentage was 32.5%, while in the group of 3-5 years old increased to 59.4% and in the mares in the age of 6-10 years and older than 10 years 89.5% and 95% were seropositive, respectively. Among 11 seropositive stallions five were supposed to be shedders of EAV with their semen. It is likely that those persistently infected stallions were the reservoirs of the virus in the stud. Genetic studies using of ORF5 gene showed high homology between the viruses detected in the semen of those stallions what suggested lateral transmission between the stallions sharing the same stable. Persistent infection in an immature stallion, which has not yet been used for breeding, was established as a result of infection via respiratory route. Phylogenetic analysis confirmed that all hucul viruses shared the same ancestor and as most of EAV strains dominating in Polish horse population belonged to the European origin EAV subgroup (EU-1).  相似文献   

Squamous cell carcinoma of the vagina and cervix in sheep - case report     

Ferrer LM  Lacasta D  Ramos JJ  Jalón JA  Ruiz De Arcaute M  Conde T 《Acta veterinaria Hungarica》2011,59(1):123-127

This report describes the clinical and histopathological characteristics of a squamous cell carcinoma infiltrating the cervix and the vaginal wall, producing reproductive symptoms and subnormal fertility in an adult ewe. Necropsy showed a large (15-cm-long) neoplastic mass infiltrating the vaginal wall and the cervix. Histopathological examination revealed atypical squamous epithelial cords invading the basal membrane and dermis, round anaplastic cells, focal areas of necrosis, keratinisation of isolated cells, and pronounced infiltration by mononuclear cells around the cords. No squamous cell carcinoma of such localisation has been reported from sheep before. In humans, this tumour is the most common gynaecological malignancy in the world.  相似文献   

Methodological aspects of determining soil particle‐size distribution using the laser diffraction method     

Magdalena Ryżak  Andrzej Bieganowski 《植物养料与土壤学杂志》2011,174(4):624-633

This paper presents the influence of selected methodological aspects on the results of particle‐size distribution (PSD) as measured by the laser diffraction method (LDM). The investigations were carried out using the Mastersizer 2000 with Hydro MU attachment (Malvern Ltd., UK). It was found that for the investigated soils: (1) optimal speed of pump and stirrer was 2500 rpm, (2) optimal measurement time was ≈ 1 min, (3) there are two, practically equivalent methods for soil‐sample dispersion: chemical (with the use of a solution of sodium hexametaphosphate) or physical (by means of ultrasound application for 4 min at a maximum power of 35W), (4) one must not use the chemical and physical dispersing methods simultaneously, because this can lead to aggregation (not dispersion) of soil particles, (5) the Fraunhofer theory (physical models) can be used to convert scattered‐light data to PSD. In the case of the Mie theory, the best results were obtained for a refractive index (RI) in the range of 1.5–1.6 and an absorption index (AI) of 1.0. It was also found that most of the discussed parameters depend on design of the measuring device and on the type and volume of the investigated suspensions. It is necessary, therefore, to explain how the data was obtained every time and to specify the details in the methodological part of the paper.  相似文献   

Histological effects on the kidney,spleen, and liver of Nile tilapia Oreochromis niloticus fed different concentrations of probiotic Lactobacillus plantarum     

Ruiz  Maria Luiza  Owatari  Marco Shizuo  Yamashita  Marcela Maya  Ferrarezi  José Victor Saffadi  Garcia  Patricia  Cardoso  Lucas  Martins  Maurício Laterça  Mouriño  José Luiz Pedreira 《Tropical animal health and production》2020,52(1):167-176

Tropical Animal Health and Production - The aims of this study were to evaluate the inclusion of different concentrations of Lactobacillus plantarum in Nile tilapia diet and to verify histological...  相似文献