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1.
The survival rate of North American bighorn sheep, Ovis canadensis, housed in several zoological gardens was analyzed. Complete herd histories, including birth and death data as well as causes of mortality, were collected from seven institutions. Lambs were divided into inbred and noninbred animals, with lambs being considered inbred if they had an inbreeding coefficient greater than zero. The rate of survival of inbred and noninbred lambs was compared using “survival equalling one year” and “survival equalling six months.” Another analysis compared the survival rate of male and female inbred lambs and male and female noninbred lambs. Age at death was also compared in inbred and noninbred lambs. The analysis of the data for the seven collections, located in various geographic areas and housing various subspecies, indicates that inbreeding depression is a mortality factor in the captive management of North American bighorn sheep. Therefore, long-term survival of captive or isolated wild populations will depend on maintaining genetic diversity within the herds through careful selection of breeding stock in captive populations and introduction of nonrelated animals into isolated wild populations.  相似文献   

2.
The causes of lamb mortality in two highly prolific flocks (mean litter size 1.83–2.45) and a flock of medium prolificacy (litter size 1.4) were determined by autopsy. Causes of death were categorised into six major groups (prenatal, dystocia, prolonged birth, starvation, starvation/CNS, others) and the effects of year, ewe age, and litter size on the distribution of mortality between these groups were examined. Year and litter size effects were large, with ewe age effects relatively small.Dystocia was the dominant cause of death for single lambs (2.5–15.9% of lambs born) while for large litters “prenatal” and “prolonged birth” categories were of increasing importance with increased litter size (6.9–26.1% of lambs born). “Starvation” contributed a smaller proportion of deaths than previously reported for less prolific flocks.  相似文献   

3.
On May 25, 2005, Ireland lodged the first example of a so-called “partial submission” to the Commission on the Limits of the Continental Shelf in respect of an allegedly “undisputed” area of seabed beyond 200 nm limits sandwiched between disputed and extensive seabed claims to the north (Hatton-Rockall Area) by Denmark/Faroes and Iceland, and an as yet undelimited seabed area to the south (the Celtic Shelf) where the United Kingdom, France, and Spain may also have seabed claims. This article considers the problems that may arise even from this supposedly uncontroversial type of submission in the light of the diplomatic reaction by both Denmark/Faroes and Iceland in August 2005.  相似文献   

4.
The Iceland population of Anguilla eels contains an elevated frequency of fish with vertebral numbers lower than those typical of European localities. Several distinct hypotheses have been advanced to account for these morphologically atypical fish: for example, they could represent (1) genetically “pure” American expatriates, (2) genetically “pure” European types with ontogenetic abnormalities, or (3) hybrids between American and European forms. Here we critically test these and other possibilities by examining the joint distributions of allozyme markers, mitochondrial DNA markers, and vertebral numbers in Icelandic eels. The particular patterns of association among the genetic and morphological traits demonstrate that the Iceland population includes, in low frequency, the products of hybridization between American and European eels. Approximately 2–4% of the gene pool in the Iceland eel population is derived from American eel ancestry. This hybrid zone is highly unusual in the biological world, because the mating events in catadromous eels presumably take place thousands of kilometers from where the hybrids are observed as maturing juveniles. The molecular data, in conjunction with the geographic distributions, strongly suggest that the differences in migrational behavior and morphology between American and European eels include an important additive genetic component. Evolutionary hypotheses are advanced to account for the original separation of North Atlantic eels into American and European populations, and for the presence of hybrids in Iceland.  相似文献   

5.
The aim of this study was to determine how one group of lambs utilized 2 consecutive rest periods in novel environments with access to food and water that occurred during 22 hr of motor transport. The 18.5 ± 0.6 kg lambs (n = 15) were transported for 8 hr and then unloaded for a 6-hr rest period. After 6 hr, the lambs were reloaded for another 8 hr of transport followed by a 24-hr rest period. Reloading for a second 8 hr of transport followed the initial rest period. The percentage of lambs engaged in drinking, eating, lying, playing, or “other” was determined at 15-min intervals. During the 6-hr rest period, peak lying behavior occurred during the 2nd and 6th hr of the period. During the first 6 hr of the 24-hr rest period, the percentage of lambs lying increased while the percentage of lambs eating decreased. In addition, the percentage of lambs lying during the first 6 hr of the 24-hr rest period was greater than during the 6-hr rest period. Lying down had a greater priority than eating during the second (24-hr) rest period.  相似文献   

6.
Based on changes in planktonic foraminifer assemblages and carbonate content of deposits in the sedimentation column from the northeastern Iceland Basin, nine isotope stages are recognized, covering 300 ka. The study of benthic foraminifer assemblages in the section has shown that, most of this time, it contained “old” water, isolated for a long time from the surface, with a low content of oxygen. At transitions from glacial conditions to interglacials, it was displaced by North East Atlantic Deep Water.  相似文献   

7.
Paton G., Thomas R. J. and Waller P. J. 1984. A prediction model for parasitic gastroenteritis in lambs. International Journal for Parasitology14: 439–445. The parasite Ostertagia circumcincta is a major cause of parasitic gastro-enteritis in lambs in temperate countries. A prediction model is described, based on a mathematical representation of the external and internal stages of the life-cycle.The model is used to predict the numbers of infective larvae on a permanent experimental paddock grazed by ewes and lambs in 1973 and 1974. The “moisture status” of the surface layer of the pasture was found to be of fundamental importance for the successful prediction of the development and survival of the pre-infective larval stages. For the years studied the contribution to the summer wave of infection by lamb derived larvae was particularly significant.  相似文献   

8.
In 1988, 315 lambs from 4 sheep (Ovis aries) herds comprised of 1003 animals were marked with silent mortality transmitters in Gammeldalen in Hedmark County, southern Norway. The aim was to identify causes of death and the so-called “hidden loss” of lambs on summer range. A total of 22 animals, 19 lambs and 3 ewes were found dead. Of these, 18 lambs were marked with radio transmitters. A total of 10 animals died of disease (45.5 %) and 12 were killed by predators (54.5 %). Of the 18 radio-located lambs, 6 died of disease (33.3 %) and 12 due to predators (66.7 %). Various common lamb diseases were diagnosed, e.g. lung, thoracic and intestinal infections. Eleven lambs were killed by lynx (Lynx lynx), a 12th was found chased to exhaustion, presumably by a predator. Use of mortality transmitters is concluded to be useful in investigating sheep losses on Norwegian ranges.  相似文献   

9.
Two groups (A and B) of Ile-de-France (IF) (n=6) ram lambs born in mid-October and 3 groups (C, D, E) of Dairy Lacaune (Lac) (n=15) ram lambs born in November were used in this study. Experimental ram lambs were exposed at 10 (IF) or at about 9 (Lac) weeks of age to long days (LD) for 11 weeks (group B) or 8 weeks (groups D, E) then to short days (SD) for respectively 14 and 16 weeks. Following exposure to artificial light, all experimental animals were returned to the control animals' (A,C) barn. LD treatment consisted of either 8 h of light split into two periods, one of 7 h and one of 1 h given 16 h after the beginning of the 7-h light period (“LD flash”, groups B and D) or by progressively increasing the light duration from 10 h (14 h of darkness) to 16 h (8 h D) (“LD 16”, group E). SD treatments consisted of progressively decreasing daylength from 16 h (8 D) to 8 h (16 D) (groups B, D, E).Scrotal diameter, TD (IF, Lac) and testis volume, TV (IF) were recorded regularly from January to the end of June (IF) or mid-July (Lac) and from mid-September to mid-November (IF).As expected, average body weight of treated and control animals was never significantly different in either breed.In IF from January to March, TD and TV increased in both groups but more rapidly in animals of group B. Afterwards, testes size continued to increase in experimental lambs whilst it remained almost constant in control animals. At the end of the photoperiodic treatment (31 May), TD and TV were much higher in treated than in control animals. From mid-September to mid-November, TD and TV increased rapidly in Group A and became significantly higher again than in the control lambs.In Lac TD was significantly higher in the light-treated lambs only from the 14th week onwards (just prior to the elimination of certain animals in each group). It was also similar throughout the experiment in groups D and E.These results show that exposure of ram lambs (born in autumn) to long days and then to short days accelerates their sexual development but this effect varies according to the breed.  相似文献   

10.
Ten well-annotated genomes of “Sulfolobus islandicus” strains from different geographic locations have been released at the NCBI database. Whole genome based composition vector trees indicate that these strains show the same branching patterns as originally reported by multi-locus sequence analysis. To determine whether the ten strains meet the criteria for separate species, DNA–DNA hybridization (DDH) was performed in silico. DDH values of strains from the same geographic location, i.e., Iceland, Kamchatka and North America, ranged from 82.4 to 95.4 %, clearly qualifying them as members of the same species. The lowest DDH values found between locations ranged from 75.5 to 76.6 %, which exceed the 70 % DDH threshold for a species thereby indicating they are all members of the same species based on the currently accepted definition. The clear divergences of strains from the different geographic locations are sufficiently great to consider them as separate geovars. “S. islandicus” has not yet been validly named and a type strain has not been deposited in culture collections. We urgently recommend that those who study the organism fulfill the criteria of the International Code of Nomenclature of Bacteria in order to designate a type strain and to identify and deposit related strains of this species to make them available to the broader scientific community.  相似文献   

11.
Ron W. Summers 《Ostrich》2013,84(2):167-173
Summers, R. W. 1994. The migration patterns of the Purple Sandpiper Calidris maritima. Ostrich 65: 167–173.

The Purple Sandpiper breeds largely in the Arctic, and winters (boreal season) on the rocky shores of the north Atlantic, further north than any other sandpiper. As the populations from Canada, Greenland, Iceland, Svalbard, Norway and Russia differ in wing and bill lengths it is possible to match measurements taken from breeding birds with samples of birds caught in winter. Ringing recoveries, especially from colour marked birds, have also helped to determine migration routes and wintering areas. Four populations move to the nearest ice-free coast. Two populations move south of the nearest ice-free coast, being replaced by larger birds from a more northerly population (“chain migration”). Only the north Canadian population is believed to migrate a long distance, “leap-frogging” other winter populations. These patterns are discussed in relation to theories for the migration patterns of waders.  相似文献   

12.
ObjectivesThe aim of this study was to determine the association of “ABO” and “Rhesus” blood groups with incidence of breast cancer.MethodsIn this study, we identified 70 research documents from data based search engines including “PubMed”, “ISI-Web of Knowledge”, “Embase” and “Google Scholar”. The research papers were selected by using the primary key-terms including “ABO blood type”, “Rhesus” blood type and “breast cancer”. The research documents in which “ABO” and “Rhesus” blood types and breast cancer was debated were included. After screening, we reviewed 32 papers and finally we selected 25 research papers which met the inclusion criteria and remaining documents were excluded.ResultsBlood group “A” has high incidence of breast cancer (45.88%), blood group “O” has (31.69%); “B” (16.16%) and blood group “AB” has (6.27%) incidence of breast cancer. Blood group “A” has highest and blood group “AB” has least association with breast cancer. Furthermore, “Rhesus +ve” blood group has high incidence of breast cancer (88.31%) and “Rhesus –ve” blood group has least association with breast cancer (11.68%).ConclusionBlood group “A” and “Rhesus +ve” have high risk of breast cancer, while blood type “AB” and “Rhesus –ve” are at low peril of breast cancer. Physicians should carefully monitor the females with blood group “A” and “Rh +ve” as these females are more prone to develop breast cancer. To reduce breast cancer incidence and its burden, preventive and screening programs for breast cancer especially in young women are highly recommended.  相似文献   

13.
Diet of arctic foxes (Alopex lagopus) in Iceland   总被引:2,自引:0,他引:2  
Arctic foxes, Alopex lagopus , live in low productivity arctic and northern tundra habitats, where they generally prey heavily on lemmings. In Iceland, however, no lemmings are present, and the foxes have a very varied diet, including plants such as seaweed and black crowberries, a wide range of birds and invertebrates, and carcasses of large mammals such as seals, reindeer, and sheep. Marked seasonal, geographical and inter-annual differences confirm arctic foxes in Iceland as opportunistic feeders. There are coastal and inland foxes: coastal foxes feed mainly on prey derived directly or indirectly from the ocean, particularly various seabirds and seals, while inland foxes feed largely on migrant birds, such as geese, waders and passerines in summer, and ptarmigan in winter. Despite their reputation for killing lambs, in this study, lamb carcasses were found at only 19.4% of 1125 fox dens, 44% of which had only one carcass. The distance to the nearest farm and the physical condition of lambs were major determinants of the number of carcasses found at a den. We discuss the implications of arctic foxes' diet for population dynamics and group formation, and for management practices.  相似文献   

14.
Chickpea (Cicer arietinum L.) is particularly sensitive to water stress at its reproductive phase and, under conditions of water stress, will abort flowers and pods, thus reducing yield potential. There are two types of chickpea: (i) Macrocarpa (“Kabuli”), which has large, rams head‐shaped, light brown seeds; and (ii) Microcarpa (“Desi”), which has small, angular and dark‐brown seeds. Relatively speaking, “Kabuli” has been reported to be more sensitive to water stress than “Desi”. The underlying mechanisms associated with contrasting sensitivity to water stress at the metabolic level are not well understood. We hypothesized that one of the reasons for contrasting water stress sensitivity in the two types of chickpea may be a variation in oxidative injury. In the present study, plants of both types were water stressed at the reproductive stage for 14 d. As a result of the stress, the “Kabuli” type exhibited an 80% reduction in seed yield over control compared with a 64% reduction observed for the “Desi” type. The decrease in leaf water potential (Ψw) was faster in the “Kabuli” compared with the “Desi” type. At the end of the water stress period, Ψw was reduced to ?2.9 and ?3.1 MPa in the “Desi” and “Kabuli” types, respectively, without any significant difference between them. On the last day of stress, “Kabuli” experienced 20% more membrane injury than “Desi”. The chlorophyll content and photosynthetic rate were significantly greater in “Desi” compared with “Kabuli”. The malondialdehyde and H2O2 content were markedly higher at the end of the water stress in “Kabuli” compared with “Desi”, indicating greater oxidative stress in the former. Levels of anti‐oxidants, such as ascorbic acid and glutathione, were significantly higher in “Desi” than “Kabuli”. Superoxide dismutase and catalase activity did not differ significantly between the two types of chickpea, whereas on the 10th day, the activities of ascorbate peroxidase, dehydroascorbate reductase, and glutathione reductase were higher in “Desi”. These findings indicate that the greater stress tolerance in the “Desi” type may be ascribed to its superior ability to maintain better water status, which results in less oxidative damage. In addition, laboratory studies conducted by subjecting both types of chickpea to similar levels of polyethylene glycol‐induced water stress and to 10 μ.mol/L abscisic acid indicated a greater capacity of the “Desi” type to deal with oxidative stress than the “Kabuli” type. (Managing editor: Ping He)  相似文献   

15.
Abstract

A study was conducted on 20 “Rahmani” male lambs of 16 kg body weight fed on normal feed level and high vitamin A level (NF-HV); normal feed level and normal vitamin A level (NF-NV); low feed level and high vitamin A level (LF-HV) or low feed level and normal vitamin A level (LF-NV) till slaughter weight of 35–40 kg. Average daily gains of lambs were 211, 148, 117 and 87 g for the NF-HV, NF-NV, LF-HV and LF-NV groups, respectively. The corresponding feed conversions were 4.3, 5.9, 5.0 and 6.4 kg DM/kg gain. Raising feed intake and vitamin A level enhanced nutrients digestibility and nitrogen balance. Rumen liquor reflected higher pH value in animals fed higher intake (NF) in the first two diets. Both feed intake and vitamin A levels enhanced volatile fatty acids and ammonia concentrations in the rumen liquor. Feed intake and vitamin A levels positively affected haemoglobin content, packed cell volume, glucose, urea, total protein, vitamin A, insulin, cholesterol, phospholipids, glutamate oxaloacetate and glutamate pyruvate transaminases and alkaline phosphatase in blood. Vitamin A, insulin, cholesterol and phospholipids in blood increased gradually over the experimental period. Dressing percentages were 56.2, 49.6, 49.1 and 44.6% for the experimental groups, respectively. Liver content of glycogen and vitamin A increased with increasing feed intake and vitamin A levels. It is concluded that higher levels of vitamin A supplementation (than usually recommended) is required during fattening of lambs. Low energy and normal vitamin A levels are not recommended in lambs feeding.  相似文献   

16.
Background and objectiveSince ancient times, honey has been used due to its nutritional and therapeutic value. The role of honey has been acknowledged in the scientific literature however, its use has been controversially discussed and has not been well accepted in modern medicine especially for diabetic patients. This study aimed to investigate the role of honey in diabetic patients.MethodsIn this study, we identified 107 research articles from data based search engines including “PubMed”, “ISI-Web of Science”, “Embase” and “Google Scholar”. The research papers were selected by using the primary key-terms including “Honey”, “Honey bee” and “Diabetes Mellitus”. The research documents in which “Honey” and “Diabetes Mellitus” were debated are included. After screening, we reviewed 66 papers and finally we selected 35 studies which met the inclusion criteria and the remaining documents were excluded.ResultsThis study investigated the preclinical, clinical, human and animal model studies on honey and diabetes mellitus and found that honey decreases the fasting serum glucose, increases the sting C-peptide and 2-h postprandial C-peptide. Although, there is a dearth of data and literature also contrary discussed the use of honey in diabetic patients.ConclusionHoney decreases the fasting serum glucose, increases fasting C-peptide and 2-h postprandial C-peptide. Honey had low glycemic index and peak incremental index in diabetic patients. The use of honey in diabetic patients still has obstacles and challenges and needs more large sample sized, multi-center clinical controlled studies to reach better conclusions.  相似文献   

17.
Cholangiopathies encompass a heterogeneous group of disorders affecting biliary epithelial cells (i.e. cholangiocytes). Early diagnosis, prognosis and treatment still remain clinically challenging for most of these diseases and are critical for adequate patient care. In the past decade, extensive research has emphasized microRNAs (miRs) as potential non-invasive biomarkers and tools to accurately identify, predict and treat cholangiopathies. MiRs can be released extracellularly conjugated with lipoproteins or encapsulated in extracellular vesicles (EVs). Research on EVs is also gaining attention since they are present in multiple biological fluids and may represent a relevant source of novel non-invasive biomarkers and be vehicles for new therapeutic approaches. This review highlights the most promising candidate miRs and EV-related biomarkers in cholangiopathies, as well as their relevant roles in biliary pathophysiology. This article is part of a Special Issue entitled: Cholangiocytes in Health and Disease edited by Jesus Banales, Marco Marzioni, Nicholas LaRusso and Peter Jansen.

Research strategy

PubMed search (April 2017) was done with the following terms: “microRNA”, “miRNA”, “miR”, “extracellular vesicles”, “EV”, “exosomes”, “primary biliary cholangitis”, “primary biliary cholangitis”, “PBC”, “primary sclerosing cholangitis”, “PSC”, “cholangiocarcinoma”, “CCA”, “biliary atresia”, “BA”, “polycystic liver diseases”, “PLD”, “cholangiopathies”, “cholestatic liver disease”. Most significant articles in full-text English were selected. The reference lists of selected papers were also considered.  相似文献   

18.
The ability to recognize aphidophages is one of the key points in the protection ants provide aphids against their natural enemies. Behavior of honeydew collectors from nature (“field,” control) and laboratory reared “naive” ants of Formica pratensis Retzius, which had never met either “mature” workers or aphids and aphidophages, was observed during their pairwise interactions with ladybird imagines and hoverfly larvae. The majority of the “naive” ants perceived ladybirds as an enemy at their first encounter attacking them immediately without any prior antennation. Ants seem to have a certain innate “enemy image” that lets them react very quickly to protect aphids. Hoverfly larvae were rarely attacked by both “field” and “naive” ants (>15%). During tests with ladybirds ants from nature attacked them and also demonstrated the most aggressive reactions (series of bites and “death grip”) less frequently than the “naive” ants. The percentage of ants avoiding aphidophages after a contact with their chemical defense (reflex bleeding and glue‐like saliva) was significantly higher in the control group. Whereas the “naive” ants did not learn to avoid danger, foragers from nature usually tried to avoid negative experience and used tactics of “short bites.” Overall, experience has been proved to be unimportant for displaying key behavioral reactions underlying ant–ladybird interaction. However, accumulation of experience has been assumed to play an important role in the formation of behavioral strategy that allows honeydew collectors to drive aphidophages away with lower energy costs and avoid or minimize negative consequences of aphidophages’ chemical defense.  相似文献   

19.
The Speckled Trout blastoderm at the late high blastula stage is characterized by two different cell populations. The “light” blastomeres comprise one cell type while the “dark” and “medium” blastomeres appear to differ from one another only in degree and thus may be considered as the second type. “Dark” and “medium” blastomeres are irregular in shape, are located centrally and deep in the blastoderm, have an abundance of smooth endoplasmic reticulum with associated 520 Å glycogen particles and a single mitochondrial profile. The “light” blastomeres have randomly arranged glycogen particles in minimal quantities in contrast to the “medium” and “dark” blastomeres and in addition exhibit three mitochondrial profiles, which could however represent artifacts. It is postulated that in the Speckled Trout cellular differentiation has commenced by the third day of incubation at 10°C and that this is manifested visually by the appearance of two different cell populations; the more differentiated “dark” and “medium” blastomeres possibly destined to give rise to the hypoblast and the less differentiated “light” blastomeres.  相似文献   

20.

In March, 1991, a “Continental Encounter” of indigenous peoples took place in Quetzaltenango, Guatemala. This paper examines the photographic coverage of that event, based on interviews with the journalists, observation of their work at the Encounter, and analysis of published reports and photos. The news coverage is divided into three phases: expectations (in search of the exotic “type”), transformations (rethinking “Indianness”), and negation (institutional disregard). It is argued that the news media represent indigenous peoples as part of a “vanishing” past; exotic “others” whose existence has no relevance to the “modern” news consumer.  相似文献   

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