Search results for "Nile"

Infanticide and Population Growth in the Bank Vole (Myodes glareolus): The Effect of Male Turnover and Density

2011

One major intrinsic factor affecting recruitment of young into a population is infanticide, the killing of conspecific young by adult males. It occurs in most mammal species, like our study species the bank vole (Myodes glareolus), and is widely accepted as an adaptive behavior, which may increase male fitness via nutritional gain, decreased competition, or an increased access to mates. A turnover of males in a population increases the risk of infanticide owing to a disruption of social structures. In a controlled field study, we tested the effects of total male turnover and density on juvenile recruitment and female space use in experimental bank vole populations. Juvenile recruitment decl…

Life in varying environments: experimental evidence for delayed effects of juvenile environment on adult life history

2011

Summary 1. The effects of environment experienced during early development on phenotype as an adult has started to gain vast amounts of interest in various taxa. Some evidence on long-term effects of juvenile environment is available, but replicated experimental studies in wild animals are still lacking. 2. Here we report the first replicated experiment in wild mammals which examines the long-term effects of juvenile and adult environments on individual fitness (reproduction, survival and health). The early development of bank vole (Myodes glareolus) individuals took place in either foodsupplemented or un-supplemented outdoor enclosures. After the summer, adult individuals were reciprocally…

Association Study of Genetic Variants in the 14q11 - 14q13 Proteasomal Genes Cluster with Juvenile Idiopathic Arthritis (JIA) in Latvian Population

2009

Association Study of Genetic Variants in the 14q11 - 14q13 Proteasomal Genes Cluster with Juvenile Idiopathic Arthritis (JIA) in Latvian Population The possible role of proteasomes in the development of autoimmune diseases was hypothesised after discovery of the involvement of proteasomal LMP2 and LMP7 subunits in antigene processing. The objective of this study was to determine the association between allelic variants of the genes encoding proteasomal proteins PSME1, PSME2 and PSMA6 and juvenile idiopathic arthritis (JIA) in the Latvian population. One Indel G-4543 CA-4544 →GA and four SNPs related to the PSMA6 gene (A-2486 →G and C-1910 →T, upstream promoter, C-110 →A of promoter, and C-8…

Recovery of Historically Contaminated Watercourse Polluted by the Chemical Wood Industry: EROD Activity in Fish as Biomarker

2013

Despite outstanding process alterations over decades, pulp- and paper-mill-contaminated sediments and continuing exposure by the effluents may still have effects on biota. In this study, ecotoxicological impacts in the boreal watercourse were analyzed by measuring ethoxyresorufin-O-deethylase (EROD) induction from wild fish populations and from experimentally exposed fish. In order to assess the role of sediment-borne chemicals, juvenile rainbow trout (Oncorhynchus mykiss) were exposed in the laboratory to the surface sediments of Lake Vatianjarvi and Southern Lake Saimaa, both watercourses impacted by the chemical wood industry for approximately a century. Hepatic EROD activity was also me…

Ontogeny of gonadotropin releasing hormone and gonadotropin immunoreactivity in brain and pituitary of normal and estrogen-treated guppies, Poecilia …

1987

Gonadotropin releasing hormone (GnRH) and gonadotropic hormone (GTH) were identified by immunohistochemistry in the brains and pituitaries of neonate, juvenile and adult guppies. GTH was present in some cells of the pars intermedia (pi) and proximal pars distalis (ppd) of all animals. GnRH was found in the perikarya of the nucleus olfactoretinalis. In the pituitaries of juvenile 30-day-old guppies, GnRH-immunoreactive cells existed in a "juvenile pattern", whereas in adult animals GnRH was recognized in only a few cells. GnRH-immunoreactive fibers were seen in the pituitaries of animals that were 30 days or older. In adult guppies, the ventral and lateral ppd (the gonadotropic region) conta…

Diel feeding periodicity, daily ration and prey selectivity in juvenile brown trout in a subarctic river

1999

Feeding of age-1 brown trout Salmo trutta in a third-order river in northern Finland was usually highest in the twilight hours and lowest around midday. Diel periodicity in food intake was less distinct and rarely significant for age-0 trout. Daily rations declined seasonally, being lowest in October, and highest in June (age-1 trout) or early August (age-0 trout). Prey selection did not differ between day and night, but differences between age classes and sampling dates were distinct. Age-0 trout preferred Ephemerella nymphs in summer and Micrasema larvae later in the season. Age-1 trout fed selectively on caddis larvae on all sample dates. Aerial insects and Baetis nymphs were avoided by …

La via linguistica al femminile

2007

Strontium and Oxygen Isotope Analyses Reveal Late Cretaceous Shark Teeth in Iron Age Strata in the Southern Levant

2020

Skeletal remains in archaeological strata are often assumed to be of similar ages. Here we show that combined Sr and O isotope analyses can serve as a powerful tool for assessing fish provenance and even for identifying fossil fish teeth in archaeological contexts. For this purpose, we established a reference Sr and O isotope dataset of extant fish teeth from major water bodies in the Southern Levant. Fossil shark teeth were identified within Iron Age cultural layers dating to 8–9th century BCE in the City of David, Jerusalem, although the reason for their presence remains unclear. Their enameloid 87Sr/86Sr and δ18OPO4 values [0.7075 ± 0.0001 (1 SD, n = 7) and 19.6 ± 0.9‰ (1 SD, n = 6), res…

Low frequencies noise effects on behaviour of Sparus aurata juveniles

2019

Human activities in the oceans, such as marine traffic and Deep Sea Mining (DSM), are increasing in the last years (Ross 2005; Calvo et al 2016). Underwater noise in the oceans, especially at lower frequencies, is mainly produced by marine traffic and DSM could increase this noise in the next future. Marine Strategy Framework Directive promotes the achievement of a good quality environmental status and aims to monitor “continuous low frequency sound” trend in the ambient noise level within the 1/3 octave bands centred at 63 and 125 Hz. The aim of this study is to evaluate the behavioural changes of Sparus aurata juveniles exposed to a four different acoustic signals in a tank. The emitted s…

Susceptibility of Nile tilapia (Oreochromis niloticus) to vibriosis due to Vibrio vulnificus biotype 2 (serovar E)

2002

The present study documents the susceptibility of Nile tilapia to the experimental vibriosis caused by Vibrio vulnificus biotype 2 (serovar E) using a reference strain (Spanish Collection of Type Cultures, CECT 4604) selected for its high degree of virulence for eels. The biotype 1 of this species is one of the usual organisms involved in epizootics occurred in tilapia. After intraperitoneal injection, the selected strain developed a haemorrhagic septicaemia similar to eel vibriosis with a LD50 four log units lower than that exhibited by the type strain of the species, which belongs to the biotype 1. The results obtained in waterborne and intubation challenges indicated that water and feed …