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Feeding habits of the Cape Mountain Zebra Equus zebra zebra LINN. 1758  

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The feeding habits of the Cape mountain zebra Equus zebra zebra Linn. 1758, were studied in the Mountain Zebra National Park. They were highly selective utilising only seven of 17 available grass species at feeding sites and 26 of plants available. These zebra fed at 40 mm to 80 mm above the ground ...

J.H Grobler

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The reaction of the Cape Mountain Zebra {Equus Zebra Zebra) to certain chemical immobilisation drugs  

Digital Repository Infrastructure Vision for European Research (DRIVER)

he physiological reactions evoked by M@99 and Aza- perone in the Cape Mountain Zebra (Equus zebra Zebra) are discussed. Notes on clinical as well as physiological parameters are presented and it is concluded that these drugs can be used effectively in the capture of individuals of this rare mam...

E Young; L Penzhorn

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The reaction of the Cape Mountain Zebra {Equus Zebra Zebra) to certain chemical immobilisation drugs  

Directory of Open Access Journals (Sweden)

Full Text Available he physiological reactions evoked by M@99 and Aza- perone in the Cape Mountain Zebra (Equus zebra Zebra) are discussed. Notes on clinical as well as physiological parameters are presented and it is concluded that these drugs can be used effectively in the capture of individuals of this rare mammal.

E Young; L Penzhorn

1972-01-01

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The reaction of the Cape Mountain Zebra (Equus Zebra Zebra) to certain chemical immobilisation drugs  

Directory of Open Access Journals (Sweden)

Full Text Available he physiological reactions evoked by M@99 and Aza- perone in the Cape Mountain Zebra (Equus zebra Zebra) are discussed. Notes on clinical as well as physiological parameters are presented and it is concluded that these drugs can be used effectively in the capture of individuals of this rare mammal.

E Young; L Penzhorn

1972-01-01

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Feeding habits of the Cape Mountain Zebra Equus zebra zebra LINN. 1758  

Directory of Open Access Journals (Sweden)

Full Text Available The feeding habits of the Cape mountain zebra Equus zebra zebra Linn. 1758, were studied in the Mountain Zebra National Park. They were highly selective utilising only seven of 17 available grass species at feeding sites and 26 of plants available. These zebra fed at 40 mm to 80 mm above the ground except when eating seed heads of certain grass species. Protein levels of grasses eaten were above 4 and seasonal movements were associated with mean food quality @ there were thus summer grazing and winter grazing areas. Mean crude protein in the faeces fluctuated seasonally.

J.H Grobler

1983-01-01

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In vitro isolation of equine piroplasms derived from Cape Mountain zebra ( Equus zebra zebra) in South Africa  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Twenty blood samples of zebras ( Equus zebra zebra) from the Karoo National Park and the Bontebok National Park in South Africa, all seropositive for Theileria equi, were subjected to in vitro culture to identify carrier animals and to isolate the parasites. Sixteen animals had a detectable parasita...

Zweygarth, Erich; Meyer, P.; Lopez-Rebollar, Laura M.

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Zebra  

Science.gov (United States)

Zebras generally stay in herds together. Zebras standing together may tend to look like one very large animal to predators. Also, predatory attacks send the zebras running in every direction. The stripes could confuse the attacker as to which animal it is chasing after, leaving it without any food in the end.

André Karwath (None;)

2005-10-08

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Home range sizes of Cape Mountain Zebras Equus Zebra Zebra in the Mountain Zebra National Park  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The mean home range size of Cape mountain zebra breeding herds was 9,4 km2 (range 3,1 @ 16,0 km2). In two herds which split up, the home ranges of the resultant herds included the original home ranges, but were larger.

B. L Penzhorn

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Home range sizes of Cape Mountain Zebras Equus Zebra Zebra in the Mountain Zebra National Park  

Directory of Open Access Journals (Sweden)

Full Text Available The mean home range size of Cape mountain zebra breeding herds was 9,4 km2 (range 3,1 @ 16,0 km2). In two herds which split up, the home ranges of the resultant herds included the original home ranges, but were larger.

B. L Penzhorn

1982-01-01

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Soil-eattng by Cape Mountain Zebras Equus Zebra Zebra in the Mountain Zebra National Park  

Directory of Open Access Journals (Sweden)

Full Text Available Cape mountain zebra stallions, mares and foals ate soil at mineral licks, mainly during summer. Calcium was the only mineral with higher concentrations at the licks than in all surrounding soil samples. The influence of calcium on reproduction is discussed.

B. L Penzhorn

1982-01-01

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Descriptive study of an outbreak of equine sarcoid in a population of Cape mountain zebra (Equus zebra zebra) in the Gariep Nature Reserve  

Digital Repository Infrastructure Vision for European Research (DRIVER)

An outbreak of equine sarcoid occurred in a population of Cape mountain zebra (Equus zebra zebra) at the Gariep Nature Reserve located in the southern Free State Province of South Africa in 1996. The course of the outbreak during 1996 to 2003 is described. During this period the average population s...

P.J. Nel; H. Bertschinger; J. Williams; P.N. Thompson

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In vitro maturation and fertilization of oocytes recovered from free-ranging Burchell's zebra (Equus burchelli) and Hartmann's zebra (Equus zebra hartmannae).  

UK PubMed Central (United Kingdom)

A noninvasive repeatable method to harvest oocytes for in vitro fertilization (IVF) could potentially be used to assist reproduction in endangered equid species. The objectives of this study were to evaluate a specific transvaginal ultrasound-guided oocyte recovery procedure for use in zebra mares and the general applicability of IVF procedures in zebra. Ovaries were collected from Burchell's zebra (Equus burchelli) and Hartmann's zebra (Equus zebra hartmannae) mares at routine culling for Expt. I. Of the 144 oocytes recovered from these ovaries, 70% were of excellent quality. No significant difference in oocyte quality was found between the two zebra species. Zona drilling was performed on in vitro-matured oocytes prior to IVF. Epididymal sperm from culled Burchell's zebra stallions were used for IVF. The sperm either were exposed to calcium ionophore or were not treated and served as a control. In vitro fertilized oocytes were then co-cultured with zebra granulosa cells (ZGC) or with bovine oviduct cells (BOC) for up to 8 days. Overall, a 38% cleavage rate was obtained with 16% of sperm-exposed oocytes developing to the morula or blastocyst stage. All of the embryos that developed to at least the morula stage were cultured on BOC; whereas, none of those cultured on ZGC reached the morula stage during the same interval. Cleavage rates of oocytes inseminated with ionophore-treated or with control sperm were not significantly different, suggesting that ionophore treatment of epididymal sperm for IVF in these zebra species may be redundant. In Expt. II, 10 transvaginal ultrasound-guided oocyte aspiration procedures on five captive Burchell's zebra mares recovered a total of 33 oocytes (6.6 oocytes/female) of which 94% were considered viable. This approach may be an attractive means of producing gametes for assisted reproduction in endangered species. Furthermore, results from this study indicate that IVF may become a means of producing offspring from zebra and other equid species in the future.

Meintjes M; Bezuidenhout C; Bartels P; Visser DS; Meintjes J; Loskutoff NM; Fourie FL; Barry DM; Godke RA

1997-09-01

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Prevalence and body distribution of sarcoids in South African Cape mountain zebra (Equus zebra zebra)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

There are no reports in the literature describing any tumours, and specifically sarcoids, in zebras. The equine sarcoid, a locally aggressive, fibroblastic skin tumour, is the most common dermatological neoplasm reported in horses. The Cape mountain zebra (CMZ) has been described as one of the most ...

H.J. Marais; P. Nel; H.J. Bertschinger; J.P. Schoeman; D. Zimmerman

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Soil-eattng by Cape Mountain Zebras Equus Zebra Zebra in the Mountain Zebra National Park  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Cape mountain zebra stallions, mares and foals ate soil at mineral licks, mainly during summer. Calcium was the only mineral with higher concentrations at the licks than in all surrounding soil samples. The influence of calcium on reproduction is discussed.

B. L Penzhorn

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Prevalence and body distribution of sarcoids in South African Cape mountain zebra (Equus zebra zebra)  

Directory of Open Access Journals (Sweden)

Full Text Available There are no reports in the literature describing any tumours, and specifically sarcoids, in zebras. The equine sarcoid, a locally aggressive, fibroblastic skin tumour, is the most common dermatological neoplasm reported in horses. The Cape mountain zebra (CMZ) has been described as one of the most vulnerable mammals in South Africa with current populations existing in isolated units. All South African CMZ are descendants from no more than 30 individual animals originating from 3 populations, namely the Mountain Zebra National Park, and Kammanassie and Gamka Mountain Nature Reserves near Cradock. The possibility therefore exists that the existing populations arose from a very small gene pool and that they are considerably inbred. A reduction in major histocompatibility complex diversity due to genetic bottlenecks and subsequent inbreeding probably contributed to uniform population sensitivity and the subsequent development of sarcoid in two CMZ populations, namely in the Bontebok National Park and Gariep Nature Reserve. The entire population of CMZ in the Bontebok National Park was observed and sampled during 2002 to document the prevalence and body distribution of sarcoids. During the same year, a comparative study was carried out on an outbred population of Burchell's zebra in the Kruger National Park. The prevalence in CMZ in the Bontebok National Park was 53 %, while the Burchell's zebra in Kruger National Park had a prevalence of 1.9 %. The most common sites for sarcoid in CMZ were the ventral abdomen and limbs. Prevalence of sarcoids in horses recorded in the literature varies between 0.5%and 2%. The Gariep Nature Reserve recently reported a prevalence of almost 25 % in CMZ in the reserve.

H.J. Marais; P. Nel; H.J. Bertschinger; J.P. Schoeman; D. Zimmerman

2012-01-01

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Zebra (Equus burchelli) foraging in the Kruger National Park, South Africa  

Science.gov (United States)

A photo of a zebra (Equus burchelli) foraging in the Kruger National Park, South Africa. Zebras impact the composition of vegetation within the shrubby grassland in which they live. In turn, shortages of water and nutrients in the ecosystem impact the ability of zebras to live in these ecosystems. This photograph originally appeared on the cover of Ecology (84:8) in August of 2003.

Klemow, Kenneth

2010-02-16

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Detection of bovine papillomavirus DNA in sarcoid-affected and healthy free-roaming zebra (Equus zebra) populations in South Africa.  

Science.gov (United States)

The endangered Cape mountain zebra (Equus zebra zebra) is protected in small numbers in a few isolated populations in South African game parks. Since 1995, sarcoid lesions appeared in zebras in two of the parks. This study was undertaken to investigate if bovine papillomavirus (BPV) is associated with sarcoids in these zebras. A conventional PCR, targeting the E5 ORF of BPV, and subsequent RFLP analysis were initially used to demonstrate the presence of BPV-1 and -2 DNAs in zebra sarcoid tumours. A rapid, sensitive and reliable real-time PCR to detect and distinguish between BPV-1 and -2 infections in zebras was developed. With this assay it was demonstrated that BPV-1 and -2 DNA (either single or mixed infections) are present in sarcoid tumour, healthy skin and blood of sarcoid-affected and healthy zebras from sarcoid-affected parks as well as in the blood of zebras from parks where no sarcoid has been observed before. PMID:19428583

van Dyk, Enette; Oosthuizen, Marinda C; Bosman, Anna-Marie; Nel, Pierre J; Zimmerman, David; Venter, Estelle H

2009-02-14

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A note on motor laterality in plains zebras (Equus burchellii) and impalas (Aepyceros melampus).  

Science.gov (United States)

This observational field study used intermittent still photography to examine the distribution of motor laterality in images of two African grazing quadruped species: plains zebras (Equus burchellii) and impalas (Aepyceros melampus). Zebra images (n=708) had a laterality index of -6.21 and a Z-score of -1.65 (p=.098). Impala images (n=318) had a laterality index of -18.87 and a Z-score of -3.36 (p=.0008). The weak left motor bias in zebras aligns with that reported in domestic horses using a related method. PMID:17712714

McGreevy, P D; Landrieu, J-P; Malou, P F J

2007-09-01

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Descriptive study of an outbreak of equine sarcoid in a population of Cape mountain zebra (Equus zebra zebra) in the Gariep Nature Reserve  

Directory of Open Access Journals (Sweden)

Full Text Available An outbreak of equine sarcoid occurred in a population of Cape mountain zebra (Equus zebra zebra) at the Gariep Nature Reserve located in the southern Free State Province of South Africa in 1996. The course of the outbreak during 1996 to 2003 is described. During this period the average population size was 69 animals. Initially (1996) all affected animals were removed from the population. New cases continued to manifest and the incidence varied between 4.6% and 17.6 %. Prevalence reached 24.7% in 2002. No sexual predilection was noticed in the 39 recorded cases. Of the affected individuals, 64 % had a single lesion and no animal had more than 4 lesions. In males, the majority of lesions occurred in the inguinal area (55.17 %), whereas in females they mostly occurred on the head and neck (41.38 %). Lesions can increase 260 % in size annually and may impede movement.

P.J. Nel; H. Bertschinger; J. Williams; P.N. Thompson

2012-01-01

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Putative clinical piroplasmosis in a Burchell's zebra (Equus quagga burchelli)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A 10-year-old tame zebra gelding was presented after suffering from lethargy, nervousness, reported anaemia and icterus as well as a decreased appetite. These symptoms were seen over some months, with changing severity. The animal was immobilised, treated, and blood specimens were submitted for haem...

Lampen, F.; Bhoora, Raksha; Collins, Nicola E.; Penzhorn, Barend Louis

 
 
 
 
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Pre- and postnatal growth phenomena of Burchell's Zebra Equus Burchelli Antiquorum  

Directory of Open Access Journals (Sweden)

Full Text Available Between 1969 and 1972 growth data were collected from 175 zebra Equus burchelli antiquorum and 138 zebra embryos and foetuses from the Central District of the Kruger National Park, Republic of South Africa. Statistical analysis of data indicated no significant difference between body mass of adult stallions (range == 267,3 to 373,3 kg; mean = 318,5 kg; n = 57) and adult non-pregnant mares (range = 272,6 to 386,9 kg; mean = 321,6 kg; n = 51) (t = 0,587). The heaviest zebra had a body mass of 429,4 kilogram. This was a pregnant mare carrying a 35,2 kg foetus. Von Bertalanffy growth curves indicated that shoulder heights in young zebra may reach the adult range by one year of age, the adult body mass range is, however, only attained after three years of age. These curves also showed that age classification of free roaming zebra is only reliable up to the age of about two years, after which individual variation is too great. Stallions were significantly taller at the shoulder than mares (mean = 1,8 cm) (t = 2,032) and neck thickness was the only body dimension showing visible sexual dimorphism in adults. Here the stallion had a neck girth on average 8,1 cm greater than the mare. Regression equations for estimating body mass from body dimensions were calculated by using a standard logarithmic transformation and fitting a linear regression by the method of least squares and also by undertaking standard straight line linear regression analyses. Exponential curves obtained by the first method indicated that growth was not isometric (not linear) and that the ratios of any of the dimensions of length to body mass were con- stantly changing, i.e. growth is allometric. Marked allometric growth differences existed between the two sexes except in the case of the heart girth-body mass relationship. Comparison of growth data from E. b. antiquorum with that of E. b. boehmi from Tanzania (Sachs 1967), indicates that E. b. antiquorum is considerably larger. Body masses differ by an average of 70 kg and 102 kg for stallions and mares respectively. Average birth mass for zebra was 33,7 kg. The largest foetus had a body mass of 39,0 kilogram. Foetal growth curves are provided. The first signs of body stripes occur at between 250 and 270 days of pregnancy (gestation period = 375 days).

G.L. Smuts

1975-01-01

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Putative clinical piroplasmosis in a Burchell's zebra (Equus quagga burchelli) : clinical communication  

Directory of Open Access Journals (Sweden)

Full Text Available A 10-year-old tame zebra gelding was presented after suffering from lethargy, nervousness, reported anaemia and icterus as well as a decreased appetite. These symptoms were seen over some months, with changing severity. The animal was immobilised, treated, and blood specimens were submitted for haematology and biochemistry. This report describes molecular characterisation of Theileria equi recovered from this animal, as well as the clinical findings, treatment and historical relevance of piroplasmosis in zebra in southern Africa.

F. Lampen; R. Bhoora; N.E. Collins; B.L. Penzhorn

2012-01-01

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Home range sizes for burchell's zebra equus burchelli antiquorum from the Kruger National Park  

Directory of Open Access Journals (Sweden)

Full Text Available Annual home range sizes were determined for 49 marked zebra family groups in the Kruger National Park. Sizes varied from 49 to 566 sq. km, the mean for the Park being 164 square kilometre. Mean home range sizes for different zebra sub-populations and biotic areas were found to differ considerably. Present herbivore densities have not influenced intra- and inter-specific tolerance levels to the extent that home range sizes have increased. Local habitat conditions, and particularly seasonal vegetational changes, were found to have the most profound influence on the shape and mean size of home ranges. The large home range sizes obtained in the Kruger Park, when compared to an area such as the Ngorongoro Crater, can be ascribed to a lower carrying capacity with respect to zebra, large portions of the habitat being sub-optimal, either seasonally or annually.

G.L. Smuts

1975-01-01

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Putative clinical piroplasmosis in a Burchell's zebra (Equus quagga burchelli) : clinical communication  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A 10-year-old tame zebra gelding was presented after suffering from lethargy, nervousness, reported anaemia and icterus as well as a decreased appetite. These symptoms were seen over some months, with changing severity. The animal was immobilised, treated, and blood specimens were submitted for haem...

F. Lampen; R. Bhoora; N.E. Collins; B.L. Penzhorn

25

Management of zebras and zebra hybrids (zebroids).  

UK PubMed Central (United Kingdom)

Equine practitioners are sometimes asked to treat zebras or zebra-horse or zebra-donkey hybrids. Although these equids are subject to many of the same health issues as domestic horses, they cannot be handled like horses and generally require heavy sedation to full anesthesia, even for minor procedures. This usually necessitates the use of ultrapotent narcotics administered by remote delivery systems. This article discusses the handling, sedation, anesthesia, and common medical issues of zebras and zebra hybrids.

Wiedner EB; Lindsay WA; Isaza R

2012-01-01

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Intracardiac thrombosis in the Cape Mountain Zebra  

Directory of Open Access Journals (Sweden)

Full Text Available The Cape mountain zebra (Equus zebra zebra) is one of the rarest species of mammals in South Africa, and is threatened with extinction. At present there are less than 200 in existence, of which approximately 160 occur in the Mountain Zebra National Park near Cradock. Because of the rarity of the species and the undesirable concentration of the majority in an area of only 6 536 ha, a post-mortem examination is performed, if possible, on all animals to establish cause of death with the purpose of preventing large-scale mortalities. This is done even if the carcass is in a fairly advanced state of decomposition. Amongst the examinations so performed were two zebra which were believed to have died as a result of intraventricular thrombosis. The rarity of this condition and of the Cape mountain zebra makes a report on these cases necessary.

G.F. Bath

1975-01-01

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Stop the Zebra Mussel!  

Science.gov (United States)

A data analysis activity for assessing zebra mussel invasion risk in Virginia. Site includes background information on the zebra mussel, including methods of relocation, teacher guide, a list of additional resources, and a detailed classroom activity. Activity covers zebra mussel biology, optimal habitat characteristics, environmental impacts, action plans, and follow up activities.

Clark, Vicki P.; Miller, Thomas J.

2010-11-15

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Invasion of the zebra mussel  

Science.gov (United States)

Zebra mussels were brought to North America in the ballast water of ships. Since 1988, the zebra mussels have pushed native freshwater mussels to near-extinction. The zebra mussel invasion is a great example of time delays.

Katie Hale (CSUF;Biological Sciences)

2007-07-08

29

Juvenile Zebra fish  

Science.gov (United States)

The juvenile stage is the third stage in the zebra fish life cycle. In the juvenile stage, the zebra fish is continuing to grow in size. At this stage, the juvenile fish can feed on its own and does not need a yolk sac.

Katie Hale (CSUF;Biological Sciences)

2007-06-08

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Zebra fish juvenile  

Science.gov (United States)

The juvenile stage is the third stage in the zebra fish life cycle. In the juvenile stage, the zebra fish is continuing to grow in size. At this stage, the juvenile fish can feed on its own and does not need a yolk sac.

Katie Hale (California State University, Fullerton;Student, Biological Sciences)

2007-01-08

31

Zebra Mussels in Ireland  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The zebra mussel was reported for the first time in Ireland during 1997. It may have been introduced during or before, 1994. Information, based on eye-witness accounts from 1995 and the age structure of zebra mussels sampled during October and November 1997, suggests they first became established in...

Minchin, D; Moriarty, C

32

[Dystocia in a Grevy's zebra  

UK PubMed Central (United Kingdom)

Dystocia in a Grevy zebra, caused by faulty position of the fetus, resulted in complete prolapse of the uterus and rupture of the uterus wall. Suturing, reposition and vaginal obstruction led to the total recovery of the Grevy zebra mare.

Klöppel R

1991-01-01

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Zebra mussel mitigation; overview  

Energy Technology Data Exchange (ETDEWEB)

Zebra mussels cause a number of problems to industrial raw water users as well as having serious impact on civil structures exposed to mussel infested waters. The largest volume of water (up to 90% of the total) drawn into most industrial and power generating plants, is for cooling and heat transfer. The rest of the volume is used for other plant processes, such as make-up in steam systems, and service systems used for cleaning, air conditions, fire protection and human consumption. All raw water systems are vulnerable to zebra mussel infestation to greater or lesser degree. To-date, many different chemical and non-chemical techniques for zebra mussel control have been investigated. However, the treatment of choice for most facilities is based on chemical control. This has been the common practice in Europe and so far it has been the case in North America. This is likely to change as the environmental constraints on release of chemicals into natural water bodies continue to increase. This paper deals with the different steps raw water users should take when deciding on a mitigation strategy, the mitigation measures available to-date and those that have been proposed for the control of zebra mussels in industrial systems.

Claudi, R. [Ontario Hydro, Toronto, Ontario (Canada)

1995-06-01

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Zebra mussel monitoring  

Energy Technology Data Exchange (ETDEWEB)

In less than a decade, zebra mussels have become the latest environmental scourge to plague the North American power industry. Infestations in the Great Lakes region have already reached natural disaster proportions. The invasion shows little sign of subsiding; Michigan's inland waters are the next most likely threatened area. In the southern United States, the mussles' migration has extended about 50 miles deeper than experts had originally predicted. By the year 2000, zebra mussel monitoring and control efforts will cost business and industry $5 billion, according to the federal Aquatic Nuisance Prevention and Control Act of 1990. Estimates of more than $1 million to control mussel fouling are projected for the Great Lakes area alone. While small independent hydropower stations are not as susceptible to zebra mussles as coal or nuclear facilities, there is cause for concern. Infestations can quickly foul hydropower plant components, hampering equipment operation and reducing facility efficiency. In extreme cases, leaving the mussels unchecked can result in stoplog gate flow blockage or false water level gauge readings. Advance prevention is often an effective first-line of defense against this troublesome, rapidly spreading and extremely prolific mollusk. Mussel monitoring efforts should begin a year in advance of when zebra mussels are expected to appear in a given location. Hydropower facility components that come into contact or rely exclusively on raw water are at greatest risk, as are other external components such as embayment walls, screens, trashracks and fish ladders.

Hennagir, T.

1994-01-01

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We fight zebra mussel  

International Nuclear Information System (INIS)

[en] According to the encyclopedia, zebra mussel (lat. Dreissena polymorpha) is a mollusk. In the conditions of hydro power plants (HPP), its appearance was monitored for the first time in 2000, when there occurred problems in Kralova Hydro Power Plant (HPP). (author)

2007-01-01

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The zebra mussel  

International Nuclear Information System (INIS)

[en] The aim of this article is, on the one hand, to provide information about the zebra mussel, its behavior, its effect on the ecosystem and the problems it poses for industry (especially in the CNA cooling systems) and, on the other hand, to review the strategies and technologies needed to control de mussel and to present the solution adopted by the power plant to combat the plague. (Author).

2010-01-01

37

Zebra mussel life history  

Energy Technology Data Exchange (ETDEWEB)

The success of introduced zebra mussels (Dreissena polymorpha (Pallas) and Dreissena bugensis Andrusova) can be related in large parttot a life history that is unlike that of the indigenous freshwater fauna and yet is conserved with marine bivalves. Following external fertilization and embryological development, there is a brief trochophore stage. With the development of a velum and the secretion of a D-shaped larval shell, the larva becomes a D-shaped veliger, which is the first recognizable planktonic larva. Later, the secretion of a second larval shell leads to the last obligate free-swimming veliger stage known as the veliconcha. The last larval stage known as the pediveliger, however, can both swim using its velum or crawl using its fully-functional foot. Pediveligers actively select substrates on which they {open_quotes}settle{close_quotes} by secreting byssal threads and undergo metamorphosis to become plantigrade mussels. The secretion of the adult shell and concomitant changes in growth axis leads to the heteromyariant or mussel-like shape, which is convergent with marine mussels. Like a number of other bivalves, zebra mussels produce byssal threads as adults, but these attachments may be broken enabling their translocation to new areas. The recognition and examination of these life history traits will lead to a better understanding of zebra mussel biology.

Ackerman, J.D. [Univ. of Northern British Columbia, Prince George, British Columbia (Canada)

1995-06-01

38

How landscape scale changes affect ecological processes in conservation areas: external factors influence land use by zebra (Equus burchelli) in the Okavango Delta.  

UK PubMed Central (United Kingdom)

Most large-bodied wildlife populations in sub-Saharan Africa only survive in conservation areas, but are continuing to decline because external changes influence ecological processes within reserves, leading to a lack of functionality. However, failure to understand how landscape scale changes influence ecological processes limits our ability to manage protected areas. We used GPS movement data to calculate dry season home ranges for 14 zebra mares in the Okavango Delta and investigated the effects of a range of landscape characteristics (number of habitat patches, mean patch shape, mean index of juxtaposition, and interspersion) on home range size. Resource utilization functions (RUF) were calculated to investigate how specific landscape characteristics affected space use. Space use by all zebra was clustered. In the wetter (Central) parts of the Delta home range size was negatively correlated with the density of habitat patches, more complex patch shapes, low juxtaposition of habitats and an increased availability of floodplain and grassland habitats. In the drier (Peripheral) parts of the Delta, higher use by zebra was also associated with a greater availability of floodplain and grassland habitats, but a lower density of patches and simpler patch shapes. The most important landscape characteristic was not consistent between zebra within the same area of the Delta, suggesting that no single foraging strategy is substantially superior to others, and so animals using different foraging strategies may all thrive. The distribution and complexity of habitat patches are crucial in determining space use by zebra. The extent and duration of seasonal flooding is the principal process affecting habitat patch characteristics in the Okavango Delta, particularly the availability of floodplains, which are the habitat at greatest risk from climate change and anthropogenic disturbance to the Okavango's catchment basin. Understanding how the factors that determine habitat complexity may change in the future is critical to the conservation of large mammal populations. Our study shows the importance of maintaining flood levels in the Okavango Delta and how the loss of seasonal floodplains will be compounded by changes in habitat configuration, forcing zebra to change their relative space use and enlarge home ranges, leading to increased competition for key resources and population declines.

Bartlam-Brooks HL; Bonyongo MC; Harris S

2013-09-01

39

How landscape scale changes affect ecological processes in conservation areas: external factors influence land use by zebra (Equus burchelli) in the Okavango Delta.  

Science.gov (United States)

Most large-bodied wildlife populations in sub-Saharan Africa only survive in conservation areas, but are continuing to decline because external changes influence ecological processes within reserves, leading to a lack of functionality. However, failure to understand how landscape scale changes influence ecological processes limits our ability to manage protected areas. We used GPS movement data to calculate dry season home ranges for 14 zebra mares in the Okavango Delta and investigated the effects of a range of landscape characteristics (number of habitat patches, mean patch shape, mean index of juxtaposition, and interspersion) on home range size. Resource utilization functions (RUF) were calculated to investigate how specific landscape characteristics affected space use. Space use by all zebra was clustered. In the wetter (Central) parts of the Delta home range size was negatively correlated with the density of habitat patches, more complex patch shapes, low juxtaposition of habitats and an increased availability of floodplain and grassland habitats. In the drier (Peripheral) parts of the Delta, higher use by zebra was also associated with a greater availability of floodplain and grassland habitats, but a lower density of patches and simpler patch shapes. The most important landscape characteristic was not consistent between zebra within the same area of the Delta, suggesting that no single foraging strategy is substantially superior to others, and so animals using different foraging strategies may all thrive. The distribution and complexity of habitat patches are crucial in determining space use by zebra. The extent and duration of seasonal flooding is the principal process affecting habitat patch characteristics in the Okavango Delta, particularly the availability of floodplains, which are the habitat at greatest risk from climate change and anthropogenic disturbance to the Okavango's catchment basin. Understanding how the factors that determine habitat complexity may change in the future is critical to the conservation of large mammal populations. Our study shows the importance of maintaining flood levels in the Okavango Delta and how the loss of seasonal floodplains will be compounded by changes in habitat configuration, forcing zebra to change their relative space use and enlarge home ranges, leading to increased competition for key resources and population declines. PMID:24101973

Bartlam-Brooks, Hattie L A; Bonyongo, Mpaphi C; Harris, Stephen

2013-07-22

40

ZEBRA 1.0 -- User manual  

CERN Multimedia

ZEBRA, the Zurich Extragalactic Bayesian Redshift Analyzer, is a tool for estimating redshifts and template types of galaxies using medium- and broad-band photometric data. ZEBRA employs novel techniques within the template-fitting approach to produce high-quality Maximum-Likelihood and Bayesian redshift estimates. This manuscript serves as a user guide to ZEBRA. It explains how to use ZEBRA, specifies input and output formats, and gives a short account of the available options. ZEBRA is a free and open-source software distributed under the GNU Public License 3 and available at http://www.exp-astro.phys.ethz.ch/ZEBRA . There are several upgrades being implemented in ZEBRA currently. An updated documentation will be provided at each new release. Any problems, comments and suggestions on the code and the manual should be sent via e-mail to zebra@phys.ethz.ch.

Feldmann, R

2008-01-01

 
 
 
 
41

Zebra mussel mortality with chlorine  

Energy Technology Data Exchange (ETDEWEB)

The rate of mortality of the zebra mussel in response to chlorine is described by a kinetic model that combines a statistical characterization of mussel mortality with a disinfection-type modeling approach. Parameter estimates were made with nine sets of data from experiments conducted in Niagara River water. From the kinetic model, an operational diagram was constructed that describes the time to 95% mortality as a function of chlorine concentration and temperature. Either the model or the diagram can be used to assist utilities in planning chlorination treatments for controlling zebra mussels.

Van Benschoten, J.E.; Jensen, J.N.; Harrington, D. [State Univ. of New York, Buffalo, NY (United States); DeGirolamo, D.J. [O`Brien and Gere Engineers, Syracuse, NY (United States)

1995-05-01

42

Zebra Mussel Research Technical Notes. Section 1 - Environmental Testing.  

Science.gov (United States)

This is Zebra Mussel Research Technical Notes reports. It contains the issues with different contents on The Zebra Mussel: Biology, Ecology, and Recommended Control Strategies, Larval Monitoring in a Chlorine Treatment Program to Prevent Zebra Mussel Sett...

1998-01-01

43

Invasion of the zebra mussels  

Energy Technology Data Exchange (ETDEWEB)

This article describes the threat to efficiency and cost control that zebra mussels are to power plants and the raw-water intakes and pumping facilities for industrial and municipal water users. The topics of the article include control measures such as chlorination, use of potassium permanganate, and other options such as thermal backwashing and physical cleaning of intake piping.

Giacomo, R.S.; Randell, N.G. [R and D Engineering, Buffalo, NY (United States)

1993-05-01

44

Habitat utilisation by Cape mountain zebras in the Mountain Zebra National Park, South Africa  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study investigated the seasonal patterns of vegetation community use by the Cape mountain zebra within the Mountain Zebra National Park over one seasonal cycle. Day-time censuses revealed that the zebras utilised all the different vegetation commu- nities that were defined in the park, with the...

A. Winkler; N. Owen-Smith

45

The ZEBRA project - past and present  

International Nuclear Information System (INIS)

[en] The 300 mA 10 MeV proton accelerator designed for the ZEBRA (Zero Energy BReeder Accelerator) Project is a test accelerator to demonstrate construction and operation techniques required for the cw injector of an accelerator breeder that could produce fissile material for nuclear power stations. The technology development program underway at CRNL is described in the context of the overall goals of the program. Developments in ion sources, radiofrequency quadrupole structures, drift-tube structures, beam transport, diagnostics, controls and modelling will be highlighted. Status of the ZEBRA project and the high power pre-ZEBRA experiments is given with a projection on future ZEBRA related activities. (orig.)

1984-01-01

46

Internal resistance of zebra batteries; Innenwiderstandsverhalten von Zebra-Batterien  

Energy Technology Data Exchange (ETDEWEB)

The charging characteristics of zebra batteries (Na/NiCl{sub 2}) differ from those of other battery systems: Independent of the charge state, the recharged energy volume is available at the next discharge at low internal resistance, i.e. at a high voltage level. This means that the performance factor of the system increases during dynamic loading. (orig.) [Deutsch] Das Verhalten der Zebra-Batterie (Na/NiCl{sub 2}) unterscheidet sich bei Zwischenladevorgaengen wesentlich von anderen Batteriesystemen. Die rueckgespeiste oder nachgeladene Energiemenge steht - unabhaengig vom Ladezustand - in der darauffolgenden Entladung bei geringem Innenwiderstand und damit hohem Spannungsniveau zur Verfuegung. Dies fuehrt dazu, dass gerade bei dynamischen Belastungen der Systemnutzungsgrad ansteigt. (orig.)

Angloher, J. [Technische Univ. Muenchen (Germany); Prassek, A. [AEG Anglo Batteries, Ulm (Germany); Wagner, U. [Technische Univ. Muenchen (Germany)

1996-08-01

47

Detroit Edison conquers zebra mussels  

Energy Technology Data Exchange (ETDEWEB)

A potentially troublesome zebra mussel infestation at Detroit Edison's Harbor Beach Power Plant was nipped in time. Reducing the oxygen content of water inside the plant's water systems and using steam to thermally treat a colony of mussels that was established in the plant's screenhouse prevented the problem. So successful was the temperature treatment that it will be used regularly as part of the plant's annual mussel removal program.

Harwood, D.B.; Buda, D.J. (Detroit Edison Co., MI (United States))

1993-11-01

48

The Swiss ZEBRA battery system  

Energy Technology Data Exchange (ETDEWEB)

The ZEBRA{sup R} advanced battery technology, which was discontinued in recent years, has now returned to the market after MES-DEA of Switzerland acquired the complete system for commercialization. The ZEBRA{sup R} battery technology consists of nickel and salt electrode materials combined with a {beta}-alumina ceramic electrolyte. The Ah-efficiency of the battery is 100 per cent, the theoretical specific energy is 790 Wh/kg. The desired voltage and capacity of different battery types is achieved by connecting the cells in series and in parallel. The low voltage version is used mostly for cars and vans. The high voltage version is used for hybrid electric-powered trucks and buses. The smallest unit size produced today is about 10 kWh and there is no limit for the upper end. The current standard battery is the Z5C. The ZEBRA{sup R} chemistry is such that it inherently contributes to safety by the reaction of the liquid electrolyte with the sodium in case of a ceramic crack. This reaction produces one third less energy than the normal cell reaction, absorbs the available sodium and partially relaxes the cathode. In addition, no material can escape because all materials have low vapour pressure even at high temperatures. Projects are underway to develop this battery for use in transit buses (214 kWh), school buses (125 kWh) and shuttle buses. The goal is to develop this battery to enable full scale commercialization of electric-powered vehicles. The new ZEBRA{sup R} plant is currently under construction. It is forecasted that the plant will produce at least 400 - 5k and 30k units per year depending on the demand. refs., tabs., figs.

Dustmann, C.H. [MES-DEA (Switzerland)

2000-07-01

49

Steam treatment of zebra mussels  

Energy Technology Data Exchange (ETDEWEB)

Steam injection into intake bays is a nonchemical method to control zebra mussels. This technique was demonstrated at Dairyland Power Cooperative`s J.P. Madgett Station located in Alma, Wisconsin. The project was funded by the EPRI Zebra Mussel Consortium which includes: Dairyland Power Cooperative, Central Illinois Public Service, Duke Power, Illinois Power Company, PSI Energy, Public Service Electric & Gas, and Tennessee Valley Authority. This technique can be used by other power plants around the nation. The steam treatments were performed at the J.P. Madgen intake in Alma, Wisconsin, on September 14 and 18, 1994. The J.P. Madgen Station has two water intake bays with capacities of approximately 295,000 gallons and 265,000 gallons each. Each intake can be isolated, permitting either full or reduced generation depending on river temperature conditions. In addition to the intake bays, the outside fire protection loop and hydrants were also treated with the hot water from one of the bays. This paper presents the process design, piping and steam educator configurations, portable industrial boiler sizing and description, and the thermocouples to monitor the water temperature in the intake bay. The biological mortality and control test protocol and treatment results are also presented. Treatment effectiveness was 100%, however equipment installation and operation was more problematic than anticipated. 3 refs., 5 figs., 2 tabs.

Tsou, J. [Electric Power Research Institute, Palo Alto, CA (United States); Rybarik, D.L.; Thiel, J. [Dairyland Power Cooperative, La Crosse, WI (United States); Mussalli, Y.G.; Collins, F. [Stone & Webster Environmental Technology & Services, Boston, MA (United States)

1996-08-01

50

Controlling zebra mussel infestations at hydroelectric plants  

Energy Technology Data Exchange (ETDEWEB)

U.S. and Canadian utilities in the great lakes area have adopted techniques to temporarily prevent infestation of the zebra mussel in their hydro facilities, but are still looking for more permanent solutions.

Sblendorio, R.P.; Malinchock, J.C. (New York Power Authority, Lewiston, NY (United States)); Claudi, R. (Ontario Hydro, Toronto, Ontario (Canada))

1991-07-01

51

Gli indici su Koha: indicizzare con Zebra  

Directory of Open Access Journals (Sweden)

Full Text Available This article describes the tool that the ILS Koha uses to build Opac and z39.50 server: Zebra software of Index Data. Describes its major features and how Koha uses it.L’articolo presenta lo strumento software usato da Koha come base per l’Opac e server z39.50: Zebra di Index Data. Si analizzano le sue caratteristiche principali e l’uso che ne fa Koha.

Zeno Tajoli

2012-01-01

52

Comparing transcriptional activation and autostimulation by ZEBRA and ZEBRA/c-Fos chimeras.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The lytic cycle of Epstein-Barr virus (EBV) can be activated by transfection of the gene for ZEBRA, a viral basic-zipper (bZip) transcriptional activator. ZEBRA and cellular AP-1 bZip activators, such as c-Fos, have homologous DNA-binding domains, and their DNA-binding specificities overlap. Moreove...

Kolman, J L; Taylor, N; Gradoville, L; Countryman, J; Miller, G

53

Zebra mussels. The assault continues  

Energy Technology Data Exchange (ETDEWEB)

Over the past seven years, zebra mussel infestation has spread relentlessly, fouling up utility cooling intakes and other industrial operations that draw fresh water. The striped invader has flourished in all of the Great Lakes and most of the major river systems east of and including the Mississippi. It has also migrated much deeper into the South than experts anticipated and is making its way westward. Now biologists have turned up a separate, look-alike species they fear may be just as destructive. EPRI is continuing its work to improve control techniques and has published a comprehensive monitoring and control guide that outlines the best practices currently available for dealing with the mussel problem. This article reviews the results of this work.

Lamarre, L.

1993-09-01

54

Steam treatment of zebra mussels  

Energy Technology Data Exchange (ETDEWEB)

Steam injection into intake bays is a nonchemical method to control zebra mussels. This technique was demonstrated at Dairyland Power Cooperative`s J.P. Madgett Station located in Alma, Wisconsin. The project was funded by the EPRI Zebra Mussel Consortium which includes: Dairyland Power Cooperative, Central Illinois Public Service, Duke Power, Illinois Power Company, PSI Energy, Public Service Electric & Gas, and Tennessee Valley Authority. This technique can be used by other power plants with a similar problem. A contract between Electric Power Research Institute (EPRI) and Stone & Webster Engineering Corporation (Stone & Webster) was initiated in August 1994. The steam treatments were performed at the J.P. Madgett intake in Alma, Wisconsin, on September 14 and 18, 1994. The J.P. Madgett Station has two water intake bays with storage capacities of approximately 295,000 and 265,000 gallons, respectively. Each intake can be isolated, permitting either full or reduced generation depending on river temperature conditions. In addition to the intake bays, the outside fire protection loop and hydrants were also treated with the hot water from one of the bays. This paper presents the process design, piping and steam educator configurations, portable industrial boiler sizing and description, and the thermocouples to monitor the water temperature in the intake bay. The biological mortality and control test protocol and treatment results are also presented. Treatment effectiveness was 100%; however, equipment installation and operation was more problematic than anticipated. A generic computer program is developed and verified using thermal data from the test. The PC program will allow other utilities to size the boiler and estimate the heat losses from an intake bay. The treatment also provided valuable information that simplifies future applications and provides for more realistic design and installation schedules and costs.

Tsou, J. [Electric Power Research Institute, Palo Alto, CA, (United States); Rybarik, D.L.; Thiel, J. [Dairyland Power Cooperative, La Crosse, WI (United States)] [and others

1995-06-01

55

Habitat utilisation by Cape mountain zebras in the Mountain Zebra National Park, South Africa  

Directory of Open Access Journals (Sweden)

Full Text Available This study investigated the seasonal patterns of vegetation community use by the Cape mountain zebra within the Mountain Zebra National Park over one seasonal cycle. Day-time censuses revealed that the zebras utilised all the different vegetation commu- nities that were defined in the park, with the exception of the riparian bush community. Year-round the zebras made greatest use of the grassland vegetation communities, together with those shrubland and dwarf shrubland communities that offered high grass biomasses. Selectivity for vegetation communities was greatest during the wet season, when the zebras favoured those grassland communities on the plateaus over other vegetation communities on the mountain slopes and in the ravines. During the dry season the zebras showed a greater diversity in their use of vegetation communities, and made greater use of those vegetation communities on the mountain slopes and in the ravines. The results suggest that the seasonal variations in vegetation community use by the zebras were in response to changes in the annual rainfall pattern.

A. Winkler; N. Owen-Smith

1995-01-01

56

EPRI's zebra mussel monitoring and control guidelines  

International Nuclear Information System (INIS)

[en] The Electric Power Research Institute (EPRI) Zebra Mussel Monitoring and Control Guidelines is a comprehensive compilation of US and European practices. The zebra mussel has infested all the Great Lakes and is positioned to spread to the adjoining river basins. The impact of the zebra mussel on power plants is as a biofouler clogging water systems and heat exchangers. The EPRI guidelines discuss the distribution of the zebra mussel in the US, identification of the zebra mussel, potential threats to power plants, and methods to initiate the monitoring and control program. Both preventive and corrective measures are presented. Preventive measures include various monitoring methods to initiate control techniques. The control techniques include both chemical and nonchemical together with combining techniques. Corrective methods include operational considerations, chemical cleaning, and mechanical/physical cleaning. It may also be possible to incorporate design changes, such as open to closed-loop backfit, backflushing, or pretreatment for closed systems. Table 1 shows a matrix of the monitoring methods. Table 2 presents a control matrix related to nuclear, fossil, and hydro raw water systems. Table 3 is a summary of the applicability of treatments to the various raw water systems. Appendixes are included that contain specifications to aid utilities in implementing several of the control technologies

1992-01-01

57

Safeguards sealing systems for Zebra  

International Nuclear Information System (INIS)

[en] A relatively simple design has been produced for safeguards seals to be applied throughout the fuel containing areas at Zebra. It is based on the use of wire seals and regular Inspector surveillance. The application of the system would allow an Inspector to establish to a high degree of confidence that significant quantities of fuel had not been diverted during an intensive experimental programme. It would add about 5% to the time required for experiments, and careful planning would reduce this value. The inspection effort required to witness element movements during the experimental programme would average about 2 hours per day, with a further 2 hours spent each week on NDA of the fuel exposed. The Safeguards Inspector would require to spend about 25% of his time in the reactor area and would have ample time to deal with the relatively small number of fuel movements taking place in the storage area and with his duties elsewhere in the plant. During a core change, full-time inspection effort would be required for about 6 weeks each year. (author)

1983-01-01

58

ZEBRA: Zurich Extragalactic Bayesian Redshift Analyzer  

Science.gov (United States)

The current version of the Zurich Extragalactic Bayesian Redshift Analyzer (ZEBRA) combines and extends several of the classical approaches to produce accurate photometric redshifts down to faint magnitudes. In particular, ZEBRA uses the template-fitting approach to produce Maximum Likelihood and Bayesian redshift estimates based on: (1.) An automatic iterative technique to correct the original set of galaxy templates to best represent the SEDs of real galaxies at different redshifts; (2.) A training set of spectroscopic redshifts for a small fraction of the photometric sample; and (3.) An iterative technique for Bayesian redshift estimates, which extracts the full two-dimensional redshift and template probability function for each galaxy.

Feldmann, R.; Carollo, C. M.; Porciani, C.; Lilly, S. J.; Oesch, P.

2011-10-01

59

Zebra Mussel Monitoring and Control Guide  

Energy Technology Data Exchange (ETDEWEB)

The Electric Power Research Institute (EPRI) Zebra Mussel Monitoring and Control Guide is a comprehensive compilation of US and European practices as reported in the open literature as of the end of 1992. EPRI considers the guide to be a living' document and will update it periodically in order to provide results of current research on chemical and nonchemical control technologies and utility experiences. The zebra mussel has infested all of the Great Lakes and other major rivers and waterways and is positioned to spread even more to the adjoining river basins. The impact of the zebra mussel on industrial power plantsis as a biofouler that clogs water systems and heat exchangers. This EPRI guideline identifies the zebra mussel, discusses its distribution in the United States, presents the potential threats to power plants, and presents the methods to initiate monitoring and control programs. Both preventive and corrective measures are presented. Preventive measures include various monitoring methods to initiate control techniques. The control techniques include both chemical and nonchemical together with combining techniques. Corrective methods include operational considerations, chemical cleaning, and mechanical/physical cleaning. It also may be possible to incorporate design changes, such as open to closed-loop backfit, backflushing, or pretreatment for closed systems. Various appendices are included that contain specifications to aid utilities in implementing several of the monitoring and control technologies, results of chemical evaluations at Cleveland Electric Illuminating Company plants, and data on the fate of various commercial molluscicides.

1992-12-01

60

Control of zebra mussels with ultraviolet radiation  

Energy Technology Data Exchange (ETDEWEB)

This paper presents the results of research on the effects of low and medium pressure ultraviolet (UV) radiation on zebra mussel mortality carried out between 1992 and 1995. An initial 1992 study, carried out by Aquatic Sciences (ASI), showed that flow-through UV systems have the ability to kill zebra mussels and prevent them from attaching to downstream surfaces. However, this work did not include expanded testing to determine the limitations of UV radiation at higher flow rates or to further define effective working parameters. The 1994 study was carried out at the Lennox Thermal Generating Station (TGS) of Ontario Hydro in Kingston, Ontario. This study involved the testing of two open channel UV systems (medium and low pressure) in an effort to determine flow rates and volumes for which UV disinfection would be effective and practical for the prevention of zebra mussel infestation. It was recommended that medium pressure (MP) and low pressure (LP) UV systems be tested for their ability to control downstream settlement of zebra mussels, in flow-through trials.

Lewis, D.P.

1998-07-01

 
 
 
 
61

Research continues on zebra mussel control  

Energy Technology Data Exchange (ETDEWEB)

Researchers are working on many fronts to learn methods for controlling and combatting zebra mussels, a species of mussel that can attach to the inside of water intakes at hydroelectric and thermal power plants, and can reduce or block water flow. Biologists at the University of Toledo in Ohio report that compounds from the African soapberry plant called lemmatoxins are lethal to zebra mussels. In laboratory tests, researchers have determined 1 to 2 milligrams of purified lemmatoxins per liter will kill the mussels. In field tests, biologist Harold Lee flushed water through a mussel-infested pipe. He found that the berry extract killed mussels in four to eight hours, making continuous treatment of water intake pipes unnecessary, according to a report in New Scientists. The University of Toledo participated in another project, funded by the American Water Works Association Research Foundation. That project team included the cities of Toledo and Cleveland, Ohio, Finkbeiner, Pettis Strout, Ltd. consulting engineers, and researchers from Ohio's Case Western Reserve University. The team identified a chemical oxidant, sodium hypochlorite, as a cost-effective agent for controlling zebra mussels at water treatment plant intakes. Toledo has used the sodium hypochlorite and reports the chemical has cleared colonies of zebra mussels that had attached to the intake of its water treatment plant.

1993-04-01

62

Research continues on zebra mussel control  

International Nuclear Information System (INIS)

[en] Researchers are working on many fronts to learn methods for controlling and combatting zebra mussels, a species of mussel that can attach to the inside of water intakes at hydroelectric and thermal power plants, and can reduce or block water flow. Biologists at the University of Toledo in Ohio report that compounds from the African soapberry plant called lemmatoxins are lethal to zebra mussels. In laboratory tests, researchers have determined 1 to 2 milligrams of purified lemmatoxins per liter will kill the mussels. In field tests, biologist Harold Lee flushed water through a mussel-infested pipe. He found that the berry extract killed mussels in four to eight hours, making continuous treatment of water intake pipes unnecessary, according to a report in New Scientists. The University of Toledo participated in another project, funded by the American Water Works Association Research Foundation. That project team included the cities of Toledo and Cleveland, Ohio, Finkbeiner, Pettis ampersand Strout, Ltd. consulting engineers, and researchers from Ohio's Case Western Reserve University. The team identified a chemical oxidant, sodium hypochlorite, as a cost-effective agent for controlling zebra mussels at water treatment plant intakes. Toledo has used the sodium hypochlorite and reports the chemical has cleared colonies of zebra mussels that had attached to the intake of its water treatment plant

1993-01-01

63

Actinide fission rate measurements in Zebra  

International Nuclear Information System (INIS)

[en] Fission rates in U-238, Pu-239, Pu-240, Pu-241, Pu-242, Am-241, Am-243 and Cm-244 have been measured at the centre of Zebra Core 14 where the neutron energy spectrum was similar to that of the Prototype Fast Reactor. The experimental values are compared with those predicted by the FGL5 cross-section library. (author)

1977-01-01

64

ZEBRA - providing high-energy output  

Energy Technology Data Exchange (ETDEWEB)

The ZEBRA battery is a new high-energy with an energy density of approximately 100Wh/kg. The use of nickel chloride for the positive electrode and sodium for the negative electrode, in addition to a solid ceramic electrolyte together with a molten salt liquid electrolyte, combine to ensure safe, reliable and maintenance-free operation. (author)

Anon.

1996-12-31

65

Proton recoil counter techniques in ZEBRA  

International Nuclear Information System (INIS)

Spherical hydrogen-filled proton recoil proportional counters are used for measurements of neutron spectra between 5 keV and 1 MeV in fast reactor assemblies built in ZEBRA. The technique used for these measurements and their analysis is described. (author)

1969-01-01

66

CA/CPS: A Communications ZEBRA implementation using CPS  

International Nuclear Information System (INIS)

CZ/CPS is an implementation of the Communications ZEBRA distributed computing environment utilizing the CPS communications protocol. CZ/CPS is intended for parallelization of high energy physics application programs using the CERN Program Library memory and data structure management features. CZ/CPS provides transparent communication of ZEBRA data structures among cooperative processes using standard interfaces for ZEBRA I/O. Examples of usage in a CPS HBOOK4 and GEANT3 application are provided

1991-01-01

67

CA/CPS: A Communications ZEBRA implementation using CPS  

Energy Technology Data Exchange (ETDEWEB)

CZ/CPS is an implementation of the Communications ZEBRA distributed computing environment utilizing the CPS communications protocol. CZ/CPS is intended for parallelization of high energy physics application programs using the CERN Program Library memory and data structure management features. CZ/CPS provides transparent communication of ZEBRA data structures among cooperative processes using standard interfaces for ZEBRA I/O. Examples of usage in a CPS HBOOK4 and GEANT3 application are provided.

Roberts, L.A.

1991-05-01

68

Stravation tolerance of zebra mussels, Dreissena polymorpha  

Energy Technology Data Exchange (ETDEWEB)

Samples of zebra mussels, Dreissena polymorpha (n=30), were held without food at 5{degrees}, 15{degrees}, or 25{degrees}C and examined daily for mortality. Further samples of 210 mussels at each test temperature were periodically subsampled (n=10) throughout the starvation period. Tissues and shells of sampled specimens were dried to a constant weight. Zebra mussels held at 25{degrees}C experienced 100% mortality after 166 days of starvation while mussels at 15{degrees}C experienced 100% mortality after 545 days. A mortality of 60% was recorded in mussels after 524 days at 5{degrees}C. Dry shell weight (DSW) of starving zebra mussels at 25{degrees}C remained constant; at 15{degrees}C, DSW increased, likely due to deposition of new shell without increase in length. At 5{degrees}C DSW decreased possibly due to the high solubility of shell calcium carbonate at this low temperature. Dry tissue weight (DTW) decreased linearly during starvation at all test temperatures with the rate of DTW loss increasing at higher holding temperatures. Estimated percent tissue biomass reductions in a 20 mm long starved individual were 73.8% after 132 days at 25{degrees}C, 68.9% after 545 days at 15{degrees}C and 61.6% after 516 days at 5{degrees}C. When DTW loss rates were converted to O{sub 2} consumption rates (O{sub 2}), the O{sub 2} of a 20 mm long mussel was estimated to be 22.2% of prestarvation O{sub 2} at 25{degrees}C, 11.0% at 15{degrees}C and 10.2% at 5{degrees}C. Major reduction in metabolic demand in starving zebra mussels at low temperatures allows overwintering without appreciable loss of organic energy stores.

Chase, R.; McMahon, R.F. [Univ. of Texas, Arlington, TX (United States)

1995-06-01

69

The zebra mussel; El mejillon cebra  

Energy Technology Data Exchange (ETDEWEB)

The aim of this article is, on the one hand, to provide information about the zebra mussel, its behavior, its effect on the ecosystem and the problems it poses for industry (especially in the CNA cooling systems) and, on the other hand, to review the strategies and technologies needed to control de mussel and to present the solution adopted by the power plant to combat the plague. (Author).

Bertran, A.; Esparza, J.L.; Munte, L.

2010-07-01

70

Chlorine dioxide treatment for zebra mussel control  

Energy Technology Data Exchange (ETDEWEB)

Chlorine is recognized and commonly used biocide for power plant cooling water and service water treatment programs, including the control of zebra mussels. Chlorine dioxide has recently become a popular method of zebra mussel control because of its economy, safety, environmental acceptability, and effectiveness when compared to other mussel control methods. This control technique was recently demonstrated at Dairyland Power Cooperative`s Alma Generating Station on the east bank of the upper Mississippi River in Alma, Wisconsin. The project was assisted with EPRI Tailored Collaboration Program funds. The Dairyland Power Alam Generating Station consists of five generating units that utilize raw, untreated Mississippi River water for condenser, circulating, and service water supplies. The first units were built in 1947, with the final and largest unit being completed in 1960. Total station generating capacity is 200 MW. Because of recent increases in the zebra mussel density at the station intake, Dairyland Power selected the team of Nalco and Rio Linda to perform a chlorine dioxide treatment of the station`s new water systems to eradicate and control the mussels before their presence created operational difficulties. This paper will present the results of the treatment including treatment theory, design and construction of the treatment system, the method of chlorine dioxide generation, treatment concentration, analytical methods o monitoring chlorine dioxide generation, residuals and trihalomethane (THM) concentrations, protocol for monitoring treatment mortality, and the effects of chlorine dioxide and detoxification on other water chemistry parameters and equipment materials. The goal of this paper is to inform and assist users with establishing consistent and uniform practices for safely utilizing and monitoring chlorine dioxide in the eradication and control of zebra mussels.

Rybarik, D. [Dairyland Power Cooperative, La Crosse, WI (United States); Byron, J. [Nalco Chemical Company, Naperville, IL (United States); Germer, M. [Rio Linda Chemical Company, Sacramento, CA (United States)

1995-06-01

71

Zebra mussel control using acoustic energy  

Energy Technology Data Exchange (ETDEWEB)

A practical and economical device or method that reduces zebra mussel colonization without detrimental side effects is highly desirable. An ideal method is one that could be installed near, on, or in existing raw water intakes and conduits. It must have a known effect that is limited to a defined area, should have maximum effects on a targeted species, and preferably have a low life cycle cost than the current alternative methods of control and maintenance. Underwater sound could be such a desirable solution, if found to be an effective control measure for zebra mussels. Although sound most often applies specifically to acoustic energy that is audible to humans, 20 Hertz (Hz) to 20 kiloHertz (kHz), in this report we will use the terms sound and acoustic to include acoustic energy between 100 Hz and 100 MegaHertz (MHz). This research on zebra mussel biofouling is designed to effect the early developmental stages in the life cycle of Dreissena polymorpha (Pallas). Vulnerable stages in the development of D. polymorpha that might yield to site-specific acoustic deterrence measures include the free-swimming larval veliger stage, the postveliger pre-attachment demersal stage, and the immediate post-attachment stage. The proposed applications include surface treatment to prevent, reduce or eliminate colonization on underwater structures, and the stream treatment to reduce or eliminate (destroy) mussel larvae entrained in a moving volume of water.

Tiller, G.W.; Gaucher, T.A.; Menezes, J.K.; Dolat, S.W. (Sonalysts, Inc., Waterford, CT (US))

1992-01-01

72

Zebra mussel control with backwash filtration  

Energy Technology Data Exchange (ETDEWEB)

Zebra Mussels (Dreissena polymorpha) were found in North American waters in 1988 at Lake St. Clair, Michigan, when a ship from a European freshwater port released its ballast water. These organisms quickly spread from the Great Lakes to many midwestern, eastern, and southern streams and lakes. As macrofoulers, they quickly colonize new areas on many natural and artificial substrates. Zebra mussels clog intakes, piping, and screens. Power production facilities that withdraw large quantities of raw water to generate electricity and cool critical components are especially vulnerable. Many control strategies have been proposed and tested; however, not all of them are environmentally acceptable. The US Army Corps of Engineers, under the auspices of the Nonindigenous Aquatic Nuisance Prevention and Control Act of 1990, has initiated a research program to control zebra mussels at public facilities. One test being conducted under this research program is a cooperative effort between the Corps` Nashville District, the Corps` Waterways Experiment Station, and several other agencies. The test involves the design and test of a backwash filtration system for a hydropower project in the Cumberland River Basin. The preliminary design, based on lessons learned from associated tests, is discussed. In addition, recommendations for future use are presented.

Dardeau, E.A. Jr. [Army Engineer Waterways Experiment Station, Vicksburg, MS (United States); Bivens, T. [Army Engineer District, Nashville, TN (United States)

1995-12-31

73

Zebra mussel control using acoustic energy  

International Nuclear Information System (INIS)

[en] A practical and economical device or method that reduces zebra mussel colonization without detrimental side effects is highly desirable. An ideal method is one that could be installed near, on, or in existing raw water intakes and conduits. It must have a known effect that is limited to a defined area, should have maximum effects on a targeted species, and preferably have a low life cycle cost than the current alternative methods of control and maintenance. Underwater sound could be such a desirable solution, if found to be an effective control measure for zebra mussels. Although sound most often applies specifically to acoustic energy that is audible to humans, 20 Hertz (Hz) to 20 kiloHertz (kHz), in this report we will use the terms sound and acoustic to include acoustic energy between 100 Hz and 100 MegaHertz (MHz). This research on zebra mussel biofouling is designed to effect the early developmental stages in the life cycle of Dreissena polymorpha (Pallas). Vulnerable stages in the development of D. polymorpha that might yield to site-specific acoustic deterrence measures include the free-swimming larval veliger stage, the postveliger pre-attachment demersal stage, and the immediate post-attachment stage. The proposed applications include surface treatment to prevent, reduce or eliminate colonization on underwater structures, and the stream treatment to reduce or eliminate (destroy) mussel larvae entrained in a moving volume of water

1992-01-01

74

Interpretation of patterns of drifting Zebra stripes  

Energy Technology Data Exchange (ETDEWEB)

A realistic magneto-hydrostatic model of a coronal condensation over a bipolar spot group is developed and compared with the earlier interpretation of the Zebra patterns by the concept of double resonance. It is determined that the frequency drift of the Zebra stripes over a longer time cannot be explained by a change of state of the plasma as is done in previous models. The magneto-hydrostatic model utilizes a mechanism for this frequency drift which is based on a helical beam of electrons forming fronts that excite radiation at places of double resonances. Conditions are found which produce drifting Zebra stripes using considerations of the field and density configuration. It is found that structures of longer duration and absorptions arise from more or less overlapping stripe segments, which are excited by the fronts following one another in a beam of sufficient great length. It is also shown that the second stripe system of other drift direction found by Slottje (1972) arises from lateral splitting of the beam.

Mollwo, L.

1983-03-01

75

Invasion of the Zebra Mussels: A Mock Trial Activity  

Science.gov (United States)

|In this activity, students learn about the important topic of invasive species, specifically Zebra Mussels. Students role-play different characters in a real-life situation: the trial of the Zebra Mussel for unlawful disruption of the Great Lakes ecosystem. Students will also learn about jurisprudential inquiry by examining the trial process.…

Beck, Judy A.; Czerniak, Charlene M.

2005-01-01

76

Environmentally Safe Control of Zebra Mussel Fouling  

Energy Technology Data Exchange (ETDEWEB)

The two primary objectives of this USDOE-NETL contract were successfully achieved during the project: (1) to accelerate research on the development of the bacterium Pseudomonas fluorescens strain CL145A (Pf-CL145A) as a biocontrol agent for zebra mussels (Dreissena polymorpha) and quagga mussels (Dreissena rostriformis bugensis)--two invasive freshwater bivalve species that are infesting water pipes in power plants; and (2) to identify a private-sector company that would move forward to commercialize Pf-CL145A as a substitute for the current polluting use of biocide chemicals for control of these dreissenid mussels in power plant pipes.

Daniel Molloy

2008-02-29

77

Radio diagnostic of loop oscillations with wavy zebra patterns  

Science.gov (United States)

The possible reasons for the wave-like frequency drift of zebra stripes in solar radio emission are analysed. For the event of October 25, 1994 recorded by the radio spectrograph of the Astrophysical Institute Potsdam (AIP) it is shown that if the zebra pattern is due to the effect of the double plasma resonance in an inhomogeneous coronal loop, then the oscillating change of zebra stripes frequencies may be associated with fast magneto-sonic (FMS) oscillations of the magnetic flux tube. Such a conclusion is based on the agreement of the theoretically predicted FMS-mode period and its dependence on the harmonic number with the observed values.

Zlotnik, E. Ya.; Zaitsev, V. V.; Aurass, H.

78

Control of zebra mussels by electroshocking  

Energy Technology Data Exchange (ETDEWEB)

The water intake systems of power plants are threatened with blockage by zebra mussels which were recently introduced to the Great Lakes system. The use of electricity has been proposed as a means to control mussel attachment and growth in power plants. A literature search was conducted to determine the feasibility of the proposal. Applying electric fields and electrifying metallic surfaces were found to be effective in mussel control under certain conditions. Electric field applications have been used predominantely as an antifoulant to kill post-veliger and juvenile mussels as they pass through a section of water intake pipe. Electrifying conductive surfaces was identified as an effective defoulant for adult mussels. A testing program was developed to investigate the use of electric fields on zebra mussels. A test cell was constructed and experiments were carried out where mussels were exposed to electric fields ranging from 350-500 V/cm for durations of 0.1 to 90 s. Mussels exposed to electricity for 5-90 s generally required more time to recover than control mussels. Exposure length had no noticeble effect on mussel recovery. 12 refs., 10 figs., 3 tabs.

McKay, S.

1991-10-04

79

The zebra mussel: US utility implications  

International Nuclear Information System (INIS)

[en] Dreissena polymorpha, the freshwater macrofouling zebra mussel, was introduced to Lake St. Clair, near Detroit, Michigan, in 1985. It has since spread throughout Lake Erie. Its planktonic veliger larval stage disperses on water currents and adults are transported by human and natural vectors, making it likely to spread throughout most of the United States and southern Canada except for the southwestern and southern United State, where summer water temperatures are above tolerated levels. Veligers enter raw water systems on intake currents to settle and grow to adults attached by secreted byssal threads to hard surfaces. Accumulations of adults impede flow, aggravate sedimentation and corrosion, and foul small-diameter components. Settlement occurs at flow velocities less than 1.5--2.0 m/sec. Mussels can reduce effective pipe diameters and foul intake structures, steam condensers, heat exchangers, fire protection systems, and cooling tower basins. Establishment of mussels in raw water systems should be prevented because subsequent removal is difficult and expensive. Mitigation procedures include manual removal, robotic cleaning, thermal backwashing, water jetting, application of molluscicides, and possibly line pigging and acidic chemical cleaning. Control technologies include oxidizing and non-oxidizing molluscicides, robotic cleaning, shell strainers, exposure of veligers to high voltage electrical fields, thermal backwashing and sand-filtration. The United States power industry can utilize extensive European experience with this species and domestic experience with the Asian clam in its development of effective controls for zebra mussel fouling

1990-01-01

80

Embryological staging of the Zebra Finch, Taeniopygia guttata.  

Science.gov (United States)

Zebra Finches (Taeniopygia guttata) are the most commonly used laboratory songbird species, yet their embryological development has been poorly characterized. Most studies to date apply Hamburger and Hamilton stages derived from chicken development; however, significant differences in development between precocial and altricial species suggest that they may not be directly comparable. We provide the first detailed description of embryological development in the Zebra Finch under standard artificial incubation. These descriptions confirm that some of the features used to classify chicken embryos into stages are not applicable in an altricial bird such as the Zebra Finch. This staging protocol will help to standardize future studies of embryological development in the Zebra Finch. J. Morphol. 274:1090-1110, 2013. © 2013 Wiley Periodicals, Inc. PMID:23813920

Murray, Jessica R; Varian-Ramos, Claire W; Welch, Zoe S; Saha, Margaret S

2013-06-27

 
 
 
 
81

Radioheliograph observations of microwave bursts with zebra structures  

CERN Multimedia

The so-called zebra structures in radio dynamic spectra, specifically their frequencies and frequency drifts of emission stripes, contain information on the plasma parameters in the coronal part of flare loops. This paper presents observations of zebra structures in a microwave range. Dynamic spectra were recorded by Chinese spectro-polarimeters in the frequency band close to the working frequencies of the Siberian Solar Radio Telescope. The emission sources are localized in the flare regions, and we are able to estimate the plasma parameters in the generation sites using X-ray data. The interpretation of the zebra structures in terms of the existing theories is discussed. The conclusion has been arrived that the preferred generation mechanism of zebra structures in the microwave range is the conversion of plasma waves to electromagnetic emission on the double plasma resonance surfaces distributed across a flare loop.

Altyntsev, A T; Meshalkina, N S; Sych, R A; Yan, Y

2011-01-01

82

Radioheliograph Observations of Microwave Bursts with Zebra Structures  

Science.gov (United States)

The so-called zebra structures in radio dynamic spectra, specifically their frequencies and frequency drifts of emission stripes, contain information on the plasma parameters in the coronal part of flare loops. This paper presents observations of zebra structures in a microwave range. Dynamic spectra were recorded by Chinese spectro-polarimeters in the frequency band close to the working frequencies of the Siberian Solar Radio Telescope. The emission sources are localized in the flare regions, and we are able to estimate the plasma parameters in the generation sites using X-ray data. The interpretation of the zebra structures in terms of existing theories is discussed. The conclusion has been arrived at that the preferred generation mechanism of zebra structures in the microwave range is the conversion of plasma waves to electromagnetic emission on the double plasma resonance surfaces distributed across a flare loop.

Altyntsev, A. T.; Lesovoi, S. V.; Meshalkina, N. S.; Sych, R. A.; Yan, Y.

2011-10-01

83

Method of controling zebra mussels with extract of Phytolacca dodecandra  

UK PubMed Central (United Kingdom)

Zebra mussels (Dreissena polymorpha) are controlled by contacting the mussels with effective lethal amounts of an aqueous treating medium comprising molluscicidally effective portions of the berry from Phytolacca dodecandra.

LEE HAROLD H; FRALEIGH PETER C; LEMMA AKLILU

84

Drivers' speed behaviour at a zebra crossing: a case study.  

UK PubMed Central (United Kingdom)

The purpose of the study was to: (1) observe the frequency of giving way to pedestrians at the zebra crossing; (2) reveal speed adaptation problems; (3) examine if the time difference between the arrival of the pedestrian and the car have any influence on the speed of the approaching car; (4) identify so-called 'ideal' situations (in which the car brakes on the driver's own initiative in order to give way to a pedestrian) upon which recommendations can be given for implementing means to improve speed behaviour at zebra crossings. It was hypothesized that the speed behaviour of drivers approaching the zebra crossing depends on the pedestrian's arrival at the curb related to the car's expected arrival at the zebra crossing. The speed was measured on randomly selected 'free' passenger cars which approached a non-signalized mid-block zebra crossing on a two-lane arterial road. Every second a radar gun, hidden at the road side, sent the speed data to a lap-top computer in which the observer could also register pedestrians' arrival at, and start from the curb. Simultaneous video recordings were made in order to obtain a more detailed description of the interaction between the car and the pedestrian. Speed behaviour in encounters (148 observations), non-encounters with pedestrian presence (642 observations) and situations without pedestrian presence (690 observations) was compared. Situations with pedestrian priority were classified. The results show that the frequency of giving way is 5%. Drivers do not observe the law concerning speed behaviour at the zebra crossing, as they do not "adapt the speed in such way that they do not endanger pedestrians who are already on, or are about to step onto the zebra crossing". In encounters, three out of four drivers maintain the same speed or accelerate and only one out of four slows down or brakes. These results indicate that maintained high speed (even exceeding the speed limit of 50 km hour-1) is the signal from the drivers that they do not intend to give way to the pedestrian at the zebra crossing. The conclusion is that encounters between cars and pedestrians at the zebra crossing are critical situations in which the driver has to be influenced before he reaches the decision zone at 50 to 40 m before the zebra crossing in order to prevent the 'signalling by speed' behaviour. Countermeasures to improve driver behaviour at the zebra crossing are discussed.

Várhelyi A

1998-11-01

85

Drivers' speed behaviour at a zebra crossing: a case study.  

Science.gov (United States)

The purpose of the study was to: (1) observe the frequency of giving way to pedestrians at the zebra crossing; (2) reveal speed adaptation problems; (3) examine if the time difference between the arrival of the pedestrian and the car have any influence on the speed of the approaching car; (4) identify so-called 'ideal' situations (in which the car brakes on the driver's own initiative in order to give way to a pedestrian) upon which recommendations can be given for implementing means to improve speed behaviour at zebra crossings. It was hypothesized that the speed behaviour of drivers approaching the zebra crossing depends on the pedestrian's arrival at the curb related to the car's expected arrival at the zebra crossing. The speed was measured on randomly selected 'free' passenger cars which approached a non-signalized mid-block zebra crossing on a two-lane arterial road. Every second a radar gun, hidden at the road side, sent the speed data to a lap-top computer in which the observer could also register pedestrians' arrival at, and start from the curb. Simultaneous video recordings were made in order to obtain a more detailed description of the interaction between the car and the pedestrian. Speed behaviour in encounters (148 observations), non-encounters with pedestrian presence (642 observations) and situations without pedestrian presence (690 observations) was compared. Situations with pedestrian priority were classified. The results show that the frequency of giving way is 5%. Drivers do not observe the law concerning speed behaviour at the zebra crossing, as they do not "adapt the speed in such way that they do not endanger pedestrians who are already on, or are about to step onto the zebra crossing". In encounters, three out of four drivers maintain the same speed or accelerate and only one out of four slows down or brakes. These results indicate that maintained high speed (even exceeding the speed limit of 50 km hour-1) is the signal from the drivers that they do not intend to give way to the pedestrian at the zebra crossing. The conclusion is that encounters between cars and pedestrians at the zebra crossing are critical situations in which the driver has to be influenced before he reaches the decision zone at 50 to 40 m before the zebra crossing in order to prevent the 'signalling by speed' behaviour. Countermeasures to improve driver behaviour at the zebra crossing are discussed. PMID:9805516

Várhelyi, A

1998-11-01

86

ZEBRA, the first stage of an accelerator breeder program  

International Nuclear Information System (INIS)

[en] The rationale for an accelerator breeder development program at CRNL involving four stages is described along with associated economics and design optimization. A description of each stage and the opportunities available for research and development are given. The first stage, a 300 mA - 10 MeV proton linac, ZEBRA (Zero Energy Breeder Accelerator), is described in more detail including the status of siting the ZEBRA project at a new laboratory in Quebec

1983-01-01

87

Zebra mussel-directed foodchain transfer of environmental contaminants  

Energy Technology Data Exchange (ETDEWEB)

Zebra mussel densities in some near-shore areas of Lake Erie exceed 500,000 individuals m{sup 3}. Because of their large biomass, the zebra mussels can collectively filter the entire volume of Lake Erie`s western basin in approximately 7 days. In so doing, the mussels remove a significant fraction of suspended particles, including algae and sediment. If those particles are contaminated with PCBs, the mussels could potentially redirect contaminant cycling in Lake Erie. Their data show that contaminated particles are a significant source of contaminants for the zebra mussel with sediment being more significant source than algae. When particles are the source of contamination for the zebra mussel, significant foodchain contamination may result from direct consumption of contaminated mussels or via an indirect route in which unassimilated contaminants are shunted into zebra mussel feces and the latter are consumed by benthic invertebrates. Trophic transfer of PCBs from zebra mussel feces to gammarids was measured. Importantly, biomagnification of some PCB congeners occurred during foodchain transfer from particles to mussels to feces such that the indirect route of transfer through ingestion of contaminated feces is more significant ecologically. Implications for Lake Erie foodchains will be discussed.

Fisher, S.W.; Bruner, K.A. [Ohio State Univ., Columbus, OH (United States); Landrum, P.F. [Great Lakes Environmental Research Lab., Ann Arbor, MI (United States)

1994-12-31

88

The new ZEBRA-generation on the test bench; Die neue ZEBRA-Generation auf dem Pruefstand  

Energy Technology Data Exchange (ETDEWEB)

At the `Forschungsstelle fuer Energiewirtschaft` altogether ten ZEBRA Z 11-battery systems for eletric road vehicles were examined on behalf of BMW. It concerns a further development of the ZEBRA Z 8 that BMW employs in electric vehicles like the E1. Special attention was paid to analysing the electrical and thermal properties. By improving the cells and increasing the cooling power the performance could be noticeably enhanced compared to previous batteries. (orig.) [Deutsch] An der Forschungsstelle fuer Energiewirtschaft der Technischen Universitaet Muenchen wurden insgesamt zehn ZEBRA Z 11-Batteriesysteme im Auftrag der BMW AG fuer den Einsatz im Elektrostrassenfahrzeug untersucht. Dabei handelt es sich um eine Weiterentwicklung der ZEBRA Z 8, die in BMW-Elektrofahrzeugen wie dem E1 eingesetzt wurden. Besonderes Augenmerk wurde auf die messtechnische Analyse der elektrischen und thermischen Eigenschaften gerichtet. Die Verbesserung der Zellen und die Erhoehung der Kuehlleistung steigerte die Leistungsfaehigkeit gegenueber den bisherigen Batterien deutlich. (orig.)

Kranz, H.H. [BMW AG, Muenchen (Germany); Prassek, A. [AEG Anglo Batteries, Ulm (Germany); Traub, F. [Forschungsstelle fuer Energiewirtschaft, Muenchen (Germany)

1997-05-01

89

Parasites and diseases of Cape Mountain zebra, black wildebeest, mountain reedbuck and blesbok in the Mountain Zebra National Park  

Directory of Open Access Journals (Sweden)

Full Text Available The results of a special survey are supplemented inthis report with a review of all other applicable information onthe diseases and parasites of Cape mountain zebra, black wildebeest, mountain reedbuck and blesbok in the Mountain ZebraNational Park. The possible significance of some of these infections is discussed and various suggestions are made which aim atthe continued and successful preservation of the Cape mountainzebra and other species in this National Park.

E. Young; F. Zumpt; J. Boomker; B.L. Penzhorn; B. Erasmus

1973-01-01

90

Zebra: An advanced PWR lattice code  

Energy Technology Data Exchange (ETDEWEB)

This paper presents an overview of an advanced PWR lattice code ZEBRA developed at NECP laboratory in Xi'an Jiaotong Univ.. The multi-group cross-section library is generated from the ENDF/B-VII library by NJOY and the 361-group SHEM structure is employed. The resonance calculation module is developed based on sub-group method. The transport solver is Auto-MOC code, which is a self-developed code based on the Method of Characteristic and the customization of AutoCAD software. The whole code is well organized in a modular software structure. Some numerical results during the validation of the code demonstrate that this code has a good precision and a high efficiency. (authors)

Cao, L.; Wu, H.; Zheng, Y. [School of Nuclear Science and Technology, Xi' an Jiaotong Univ., No. 28, Xianning West Road, Xi' an, ShannXi, 710049 (China)

2012-07-01

91

Zebra: An advanced PWR lattice code  

International Nuclear Information System (INIS)

[en] This paper presents an overview of an advanced PWR lattice code ZEBRA developed at NECP laboratory in Xi'an Jiaotong Univ.. The multi-group cross-section library is generated from the ENDF/B-VII library by NJOY and the 361-group SHEM structure is employed. The resonance calculation module is developed based on sub-group method. The transport solver is Auto-MOC code, which is a self-developed code based on the Method of Characteristic and the customization of AutoCAD software. The whole code is well organized in a modular software structure. Some numerical results during the validation of the code demonstrate that this code has a good precision and a high efficiency. (authors)

2012-01-01

92

Doppler coefficient measurements in Zebra Core 5  

International Nuclear Information System (INIS)

Measurements using a central hot loop in Zebra Core 5 are described. Results are given for the Doppler coefficients found in a number of assemblies with PuO2 and 16% PuO2/84% depleted UO2 pins, loaded with different combinations of steel, sodium or void pins. The mixed oxide results are in general about 20% more negative than was calculated using the FD2 data set, but agreement is good if the plutonium contributions in the calculations are omitted. The small positive Doppler coefficient calculated for Pu239 was not observed, and two measurements indicated instead a small negative effect. The Doppler effect in the mixed oxide systems was found to vary approximately as 1/T. The results from the empty loop and non-fissile assemblies indicate either a small negative Doppler effect in steel or alternatively the presence of an unexplained expansion effect. (author)

1965-01-01

93

The zebra finch neuropeptidome: prediction, detection and expression  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Among songbirds, the zebra finch (Taeniopygia guttata) is an excellent model system for investigating the neural mechanisms underlying complex behaviours such as vocal communication, learning and social interactions. Neuropeptides and peptide hormones are cell-to-cell signalling molecules known to mediate similar behaviours in other animals. However, in the zebra finch, this information is limited. With the newly-released zebra finch genome as a foundation, we combined bioinformatics, mass-spectrometry (MS)-enabled peptidomics and molecular techniques to identify the complete suite of neuropeptide prohormones and final peptide products and their distributions. Results Complementary bioinformatic resources were integrated to survey the zebra finch genome, identifying 70 putative prohormones. Ninety peptides derived from 24 predicted prohormones were characterized using several MS platforms; tandem MS confirmed a majority of the sequences. Most of the peptides described here were not known in the zebra finch or other avian species, although homologous prohormones exist in the chicken genome. Among the zebra finch peptides discovered were several unique vasoactive intestinal and adenylate cyclase activating polypeptide 1 peptides created by cleavage at sites previously unreported in mammalian prohormones. MS-based profiling of brain areas required for singing detected 13 peptides within one brain nucleus, HVC; in situ hybridization detected 13 of the 15 prohormone genes examined within at least one major song control nucleus. Expression mapping also identified prohormone messenger RNAs in areas associated with spatial learning and social behaviours. Based on the whole-genome analysis, 40 prohormone probes were found on a commonly used zebra finch brain microarray. Analysis of these newly annotated transcripts revealed that six prohormone probes showed altered expression after birds heard song playbacks in a paradigm of song recognition learning; we partially verify this result experimentally. Conclusions The zebra finch peptidome and prohormone complement is now characterized. Based on previous microarray results on zebra finch vocal learning and synaptic plasticity, a number of these prohormones show significant changes during learning. Interestingly, most mammalian prohormones have counterparts in the zebra finch, demonstrating that this songbird uses similar biochemical pathways for neurotransmission and hormonal regulation. These findings enhance investigation into neuropeptide-mediated mechanisms of brain function, learning and behaviour in this model.

Xie Fang; London Sarah E; Southey Bruce R; Annangudi Suresh P; Amare Andinet; Rodriguez-Zas Sandra L; Clayton David F; Sweedler Jonathan V

2010-01-01

94

USGS Zebra Mussel Monitoring Program for north Texas  

Science.gov (United States)

The U.S. Geological Survey (USGS) Zebra Mussel Monitoring Program for north Texas provides early detection and monitoring of zebra mussels (Dreissena polymorpha) by using a holistic suite of detection methods. The program is designed to assess zebra mussel occurrence, distribution, and densities in north Texas waters by using four approaches: (1) SCUBA diving, (2) water-sample collection with plankton tow nets (followed by laboratory analyses), (3) artificial substrates, and (4) water-quality sampling. Data collected during this type of monitoring can assist rapid response efforts and can be used to quantify the economic and ecological effects of zebra mussels in the north Texas area. Monitoring under this program began in April 2010. The presence of large zebra mussel populations often causes undesirable economic and ecological effects, including damage to water-processing infrastructure and hydroelectric powerplants (with an estimated 10-year cost of $3.1 billion), displacement of native mussels, increases in concentrations of certain species of cyanobacteria, and increases in concentrations of geosmin (an organic compound that results in taste and odor issues in water). Since no large-scale, environmentally safe eradication method has been developed for zebra mussels, it is difficult to remove established populations. Broad physicochemical adaptability, prolific reproductive capacity, and rapid dispersal methods have enabled zebra mussels, within a period of about 20 years, to establish populations under differing environmental conditions across much of the eastern part of the United States. In Texas, the presence of zebra mussels was first confirmed in April 2009 in Lake Texoma in the Red River Basin along the Texas-Oklahoma border. They were most likely introduced into Lake Texoma through overland transport from an infested water body. Since then, the presence of zebra mussels has been reported in both the Red River and Washita River arms of Lake Texoma, in Sister Grove Creek, and in Ray Roberts Lake. Water managers tasked with supplying the 6.6 million residents of the Dallas-Fort Worth metropolitan area must ensure that the area receives a continuous supply of water that meets both the needs of the current (2012) and the projected (doubling in number by 2050) populations. This metropolitan area depends on surface water captured in area reservoirs, including those in the Trinity River Basin, for the primary source of drinking water. The presence of an established zebra mussel population in a reservoir in the Trinity River Basin could result in increased operations and maintenance costs for water resource managers and could potentially serve as a source population leading to further expansion of this aquatic nuisance species.

Churchill, Christopher J.; Baldys, Stanley, III

2012-01-01

95

Analysis of Western Australian zebra rock  

International Nuclear Information System (INIS)

[en] Full text: Zebra rock is a striking rock from the Ord River area of Western Australia which contains regularly spaced white and red-brown bands or rods. Its ease of working has made it popular for use in ornaments and costume jewellery. However, the mechanism for its formation has been a source of controversy for 75 years and is still not settled. Possible mechanisms proposed include slow sedimentation with regular addition of hydrated iron oxides, leaching of a reddish mudstone, post-depositional mobilisation and subsequent rhythmic precipitation of iron oxides from groundwaters, and accumulation of iron-containing minerals in ripple troughs. Loughnan and Roberts suggested a more detailed explanation and from a detailed mineralogical examination, including XRD, XRF, SEM and TEM, they concluded that the only major difference between the two coloured bands was the presence of hematite, ?-Fe2O3. In an attempt to throw more light on the problem, we have taken 57Fe Moessbauer spectra of samples from the two different coloured regions. As expected, the white coloured material contained little iron, giving a weak, broad single line spectrum at room temperature. At 78 K, the spectrum has split into a magnetic sextet which has not yet been positively identified. As expected from the XRD, the spectrum of the red part principally consists of a strong sextet due to hematite, although there is also a weak component from the phase in the white material. It is hoped that further analysis will help us to eliminate at least some of the proposed mechanisms for the formation of zebra rock

2000-01-01

96

Song Recognition in Zebra Finches: Are There Sensitive Periods for Song Memorization?  

Science.gov (United States)

|Male zebra finches learn to sing songs that they hear between 25 and 65 days of age, the sensitive period for song learning. In this experiment, male and female zebra finches were exposed to zebra finch songs either before (n = 9) or during (n = 4) the sensitive period. Following song exposure, recognition memory for the songs was assessed with…

Braaten, Richard F.

2010-01-01

97

Zebra pattern flux density observation during the type IV burst on October 12, 1981  

Energy Technology Data Exchange (ETDEWEB)

A new quantitative zebra pattern observation is reported. The mean amplitude ratio of the emission and absorption features of the irregular zebra pattern observed simultaneously with and related to an increased continuum is 3. This is not contradictory to a zebra pattern model in terms of whistler soliton propagation throughout the source of continuum emission.

Aurass, H.; Chernov, G.P.

1983-04-01

98

Copper and copper-nickel alloys as zebra mussel antifoulants  

Energy Technology Data Exchange (ETDEWEB)

Copper has been used in the marine environment for decades as cladding on ships and pipes to prevent biofouling by marine mussels (Mytilus edulis L.). This motivated the present investigation into the possibility of using copper to prevent biofouling in freshwater by both zebra mussels and quagga mussels (Dreissena polymorpha and D. bugensis collectively referred to as zebra mussels). Copper and copper alloy sheet proved to be highly effective in preventing biofouling by zebra mussels over a three-year period. Further studies were conducted with copper and copper-nickel mesh (lattice of expanded metal) and screen (woven wire with a smaller hole size), which reduced the amount of copper used. Copper screen was also found to be strongly biofouling-resistant with respect to zebra mussels, while copper mesh reduced zebra mussel biofouling in comparison to controls, but did not prevent it entirely. Preliminary investigations into the mechanism of copper antifouling, using galvanic couples, indicated that the release of copper ions from the surface of the exposed metal into the surrounding water is directly or indirectly responsible for the biofouling resistance of copper.

Dormon, J.M.; Cottrell, C.M.; Allen, D.G.; Ackerman, J.D.; Spelt, J.K. [Univ. of Toronto, Ontario (Canada)

1996-04-01

99

Analysis of Doppler Activation Measurements in ZEBRA  

International Nuclear Information System (INIS)

[en] An analysis is made of some recent Doppler activation foil measurements in the UKAEA zero-power fast reactor ZEBRA. A model is used to approximate the system of a foil, oven and heterogeneous reactor by a foil and homogenized reactor. The collision probabilities obtained by this reduction are used in the computer programme SDR-GENEX which produces a detailed continuous-energy slowing-down spectrum in the foil for the range 0-15 keV. The spectrum above 15 keV is obtained using the multigroup diffusion code SCRAMBLE. The measured (n, ?) activation ratio for a 12.19 mm X 0.254 mm U3O8/Ni foil is 1.024 ±0.003 in ZEBRA core 6A and 1.020 ± 0.003 in core 6D compared with the calculated values 1.022 and 1.020, respectively. The model, although approximate in its treatment of homogenizing the reactor core, is a useful tool for understanding the more important physics of the (n, ?) activation experiment. A comparison is made of the calculated energy distributions of the Doppler effect in the foil and in the core. It shows the median energy of each distribution to be at 900 eV and 1550 eV, respectively. This relative displacement is attributed to the differing degree of self-shielding of the 238U resonances, in the foil and in the core. In the core the background scattering cross-section is about 50 barns per 238U atom compared with an effective scattering cross-section of 250 000 barns in the. thin foil. The effect of this dilution in the foil is to lower the Doppler contribution from the predominantly scattering resonances around 1 or 2 keV and to increase the percentage contribution of the strongly absorbing low-energy resonances. We observe this as a relative shift in energy of the foil and core Doppler distributions. The analysis shows that, by equalizing the scattering cross-section per absorbing atom in the foil and core, the activation ratio and its energy distribution are also approximately equalized in the foil and core. We may therefore optimize the design of the activation experiment. For example, in a typical fast reactor core, a long circular cylinder of natural uranium would require a diameter of 0.53 cm, or a 2.54-cm-diam. disc a thickness of 0.33 cm, to produce an optimum response. (author)

1967-11-03

100

IMPACT OF WATER PH ON ZEBRA MUSSEL MORTALITY  

Energy Technology Data Exchange (ETDEWEB)

The experiments conducted this past quarter have suggested that the bacterium Pseudomonas fluorescens strain CL0145A is effective at killing zebra mussels throughout the entire range of pH values tested (7.2 to 8.6). Highest mortality was achieved at pH values characteristic of preferred zebra mussel waterbodies, i.e., hard waters with a range of 7.8 to 8.6. In all water types tested, however, ranging from very soft to very hard, considerable mussel kill was achieved (83 to 99% mean mortality), suggesting that regardless of the pH or hardness of the treated water, significant mussel kill can be achieved upon treatment with P. fluorescens strain CL0145A. These results further support the concept that this bacterium has significant potential for use as a zebra mussel control agent in power plant pipes receiving waters with a wide range of physical and chemical characteristics.

Daniel P. Molloy

2002-10-15

 
 
 
 
101

The ZEBRA battery as storage in electric networks; Die ZEBRA Batterie als Speicher in elektrischen Netzen  

Energy Technology Data Exchange (ETDEWEB)

Depending on the requirement focus a battery system must either store large magnitudes of energy as in case of day/night equalisation or generate high capacities in order to meet load peaks. Whereas the Na/S battery of the Japanese company NGK has primarily been optimised with respect to a high energy contents with a typical 8-hour discharge the ZEBRA battery (Na/ NiCl{sub 2}) offers a high capacity with one hour discharge. This battery is also suitable for fast load changes as they commonly occur in vehicles, for which this type of battery has been developed. The battery system has been tested in various vehicle-field tests and has proved its reliability. (orig.) [German] Je nach Anforderungsschwerpunkt wird von einem Batteriesystem entweder die Speicherung von moeglichst hohen Energiemengen wie beim Tag/Nachtausgleich gefordert oder eine hohe Leistung, um Leistungsspitzen schnell nachfahren zu koennen. Waehrend die Na/S Batterie von der japanischen Firma NGK primaer auf hohen Energieinhalt mit typisch 8-stuendiger Entladung optimiert wurde, bietet die ZEBRA Batterie (Na/NiCl{sub 2}) das Komplementaer fuer hohe Leistung mit typischer 1-stuendiger Entladung. Diese Batterie ist auch fuer schnelle Lastwechsel geeignet, wie sie in der Fahrzeuganwendung ueblich sind, fuer die dieser Batterietyp entwickelt wurde. Das Batteriesystem ist in verschiedenen Fahrzeug-Feldtests erprobt und hat seine Zuverlaessigkeit unter Beweis gestellt. (orig.)

Dustmann, C.H.; Prassek, A.

1998-07-01

102

FindZebra: a search engine for rare diseases.  

UK PubMed Central (United Kingdom)

BACKGROUND: The web has become a primary information resource about illnesses and treatments for both medical and non-medical users. Standard web search is by far the most common interface to this information. It is therefore of interest to find out how well web search engines work for diagnostic queries and what factors contribute to successes and failures. Among diseases, rare (or orphan) diseases represent an especially challenging and thus interesting class to diagnose as each is rare, diverse in symptoms and usually has scattered resources associated with it. METHODS: We design an evaluation approach for web search engines for rare disease diagnosis which includes 56 real life diagnostic cases, performance measures, information resources and guidelines for customising Google Search to this task. In addition, we introduce FindZebra, a specialized (vertical) rare disease search engine. FindZebra is powered by open source search technology and uses curated freely available online medical information. RESULTS: FindZebra outperforms Google Search in both default set-up and customised to the resources used by FindZebra. We extend FindZebra with specialized functionalities exploiting medical ontological information and UMLS medical concepts to demonstrate different ways of displaying the retrieved results to medical experts. CONCLUSIONS: Our results indicate that a specialized search engine can improve the diagnostic quality without compromising the ease of use of the currently widely popular standard web search. The proposed evaluation approach can be valuable for future development and benchmarking. The FindZebra search engine is available at http://www.findzebra.com/.

Dragusin R; Petcu P; Lioma C; Larsen B; Jørgensen HL; Cox IJ; Hansen LK; Ingwersen P; Winther O

2013-06-01

103

FindZebra : a search engine for rare diseases  

DEFF Research Database (Denmark)

Background: The web has become a primary information resource about illnesses and treatments for both medical and non-medical users. Standard web search is by far the most common interface to this information. It is therefore of interest to find out how well web search engines work for diagnostic queries and what factors contribute to successes and failures. Among diseases, rare (or orphan) diseases represent an especially challenging and thus interesting class to diagnose as each is rare, diverse in symptoms and usually has scattered resources associated with it. Methods: We design an evaluation approach for web search engines for rare disease diagnosis which includes 56 real life diagnostic cases, performance measures, information resources and guidelines for customising Google Search to this task. In addition, we introduce FindZebra, a specialized (vertical) rare disease search engine. FindZebra is powered by open source search technology and uses curated freely available online medical information. Results: FindZebra outperforms Google Search in both default set-up and customised to the resources used by FindZebra. We extend FindZebra with specialized functionalities exploiting medical ontological information and UMLS medical concepts to demonstrate different ways of displaying the retrieved results to medical experts. Conclusions: Our results indicate that a specialized search engine can improve the diagnostic quality without compromising the ease of use of the currently widely popular standard web search. The proposed evaluation approach can be valuable for future development and benchmarking. The FindZebra search engine is available at http://www.findzebra.com/. © 2013 Elsevier Ireland Ltd. All rights reserved.

Dragusin, Radu; Petcu, Paula

2013-01-01

104

[Zebra fish cell movements during gastrulation].  

UK PubMed Central (United Kingdom)

During zebrafish gastrulation, large cellular rearrangements create the formation of the three germ layers, ectoderm, mesoderm, and endoderm. This process includes three types of conserved morphogenetic movement: epiboly, involution, and convergent extension. Specially, the anterior movement of prechordal plate progenitors is essential for the location and differentiation of mesendoderm progenitors, and the pechordal plate progenitors'coherent migration is thought to be a good model to study the mechanism of cell movement in vivo. Gastrulation migration is known to be controlled by many signaling pathways such as Wnt/planar cell polarity signaling; however, the underlying molecular mechanism for cellular behavior remains unknown. At present, it is generally agree that cell adhesion and cytoskeletal rearrangement are critical factors during zebrafish gastrulation cell migration. In addition, the role of extraembryonic tissue (yolk syncytial layer) during gastrulation is concerned increasingly. Here, we described the essential factors for controlling cellular behaviors and highlighted the major issues and questions that require further investigation during zebra fish gastrular cell migration in order to provide a complete map containing all the factors for regulating gastrulation cell migration and their interactions on a cellular level.

Zhang T; Mo XM

2013-04-01

105

IMPACT OF WATER TEMPERATURE ON ZEBRA MUSSEL MORTALITY  

Energy Technology Data Exchange (ETDEWEB)

These tests conducted this past quarter have indicated that the bacterium Pseudomonas fluorescens strain CL0145A is effective at killing zebra mussels at water temperatures ranging from 7 to 23 C. Percent kill will likely be somewhat lower at very low temperatures, e.g., 7 C, but even at such low temperatures high mussel kill can still be achieved (>70% kill). This is significant because the development of a zebra mussel control method that is efficacious in such a wide range of temperatures broadens its usefulness as a potential commercial product.

Daniel P. Molloy

2002-08-07

106

A possible interpretation of the zebra pattern in solar radiation  

International Nuclear Information System (INIS)

[en] The nature of the zebra pattern in continual type-IV solar radio bursts is discussed. It is shown that, when a weakly relativistic monoenergetic proton beam propagates in a highly nonisothermal plasma, the energy of the slow beam mode can be negative and explosive instability can develop due to the interaction of the slow and fast beam modes with ion sound. Due to weak spatial dispersion, ion sound generation is accompanied by cascade merging, which leads to stabilization of explosive instability. The zebra pattern forms due to the scattering of fast protons by ion sound harmonics. The efficiency of the new mechanism is compared with that of previously discussed mechanisms.

2009-01-01

107

Zebra Mussels and the Mid-Atlantic: Reports from the Sea Grant Programs of New Jersey, Delaware, Maryland, Virginia and North Carolina.  

Science.gov (United States)

Contents: Foreword; Criteria for Predicting Zebra Mussel Invasions in the Mid-Atlantic Region; Potential Range of the Zebra Mussel, Dreissena polymorpha, in and near Virginia; Zebra Mussels in North Carolina; A Preliminary Assessment of the Potential for ...

1994-01-01

108

Zebra mussel chlorination benthic survey, 1990  

Energy Technology Data Exchange (ETDEWEB)

Chlorine was used for zebra mussel control at Ontario Hydro generating stations in 1990. A survey was conducted to determine whether the chlorine residues affected benthic communities in the generating station discharge plumes. Benthic samples were collected prior to and within ca 2 weeks after chlorination at Lambton, Lakeview and Nanticoke Thermal Generating Stations (TGS), and the Darlington Nuclear Generating Station. Divers collected triplicate samples at 3 reference and 3 discharge locations. The following results were obtained. The highest density of benthic organisms was present at the Nanticoke TGS in May. The lowest number of benthic organisms were present in the Lambton TGS December discharge samples. The lowest number of taxa were present in the Nanticoke TGS December discharge samples. The benthic density was significantly different at the Lakeview TGS discharge and reference sites in May. However, the December discharge and reference sites total number of organisms were not significantly different. The Lakeview TGS reference site species richness values were significantly different however, there was no significant variation in the discharge benthic richness. The variations in either reference and discharge benthic density or richness were not significant at Lambton TGS. The benthic densities were not significantly different at Nanticoke TGS reference and discharge sites in December. Benthic richness was significantly lower in the Nanticoke TGS discharge than at the reference sites however no significant variation was apparent between May and December discharge benthic richness values. It was concluded that variation within the benthic communities at each of the 4 stations surveyed was probably not attributable to the discharge of chlorine residues. 3 refs., 21 figs., 5 tabs.

Sheehan, R.W.

1991-03-20

109

Reducing costly zebra mussel infestations at power plants  

Energy Technology Data Exchange (ETDEWEB)

The fast-spreading-zebra mussel has significant potential to foul intakes and other water systems at North American hydro projects. Chemical controls can be effective in reducing infestations, but most have environmental and other drawbacks. Several non-chemical methods promise to help project operators reduce problems associated with the mussels.

Smythe, G. [Acres International Corporation, Amherst, NY (United States)

1994-10-01

110

Optimizing efficiency of zebra mussel monitoring at TVA power plants  

Energy Technology Data Exchange (ETDEWEB)

The Tennessee Valley Authority (TVA) began monitoring for zebra mussels in spring 1992 and first detected veligers entering plant intake at Shawnee, Allen and Cumberland Fossil Plans in summer 1993. Existing information indicated that densities of zebra mussel veligers at plant intakes did not always correspond to densities in critical pipe units; however, a more accurate predictive technique was unavailable. The two sites chosen for this project were Shawnee Fossil Plant on the Ohio River and Allen Fossil Plant on the Mississippi River. The project involved a coordinated series of experiments to determine how densities of zebra mussel veligers varied throughout the day, how veliger densities estimated outside the plants related to estimates at different internal locations, and how growth rate of adult zebra mussels compared using measurements taken inside and outside the plants and from the two different rivers. The data indicated no significant difference in veliger densities from samples collected at the intakes and samples collected inside the plants. There was also no significant difference in densities between samples collected inside the plants. There was also no significant difference in densities between samples taken at different times of the day. The data did indicate a significant difference in density estimates between samples collected on different days and between densities in the rivers compared to densities being drawn into the plant. The results will be used to assist plant staff in evaluating future data and in planning a more effective and cost efficient monitoring program.

Kerley, B.L. [Tennessee Valley Authority, Norris, TN (United States)

1995-06-01

111

Zebra - sõbralik ja lillelõhnaline / Ell-Maaja Randküla  

Index Scriptorium Estoniae

Tallinnas Narva mnt. 7 asuva kohviku Zebra sisekujundus. Sisearhitekt Tiiu Truus. Ehitus: AS KMG Ehitus. Materjalidest on kasutatud triibulise mustriga puitu Zebrano ja looduskivi. Laes on dekoratiivsed lipud, mille graafiline kujundus on Tiiu Priskolt ja Mati Veermetsalt. Tualettruumi looduskivist valamu ja põrandavaasi autor on Kaido Kivi. Ill.: põhiplaan, 11 värv. vaadet

Randküla, Ell-Maaja

2006-01-01

112

Floristic analysis of the Mountain Zebra National Park, Eastern Cape  

Digital Repository Infrastructure Vision for European Research (DRIVER)

As part of a larger project to assess the vegetation dynamics and conservation potential of the enlarged Mountain Zebra National Park, a checklist was produced to determine the plant species richness for this area. Six hundred and eighty species, represented by 333 genera and 87 families were identi...

U. Pond; B.B. Beesley; L.R. Brown; H. Bezuidenhout

113

Laboratory gamma-ray images using the ZEBRA telescope  

International Nuclear Information System (INIS)

[en] A series of approximately 100 laboratory images have been made with the the ZEBRA astronomical telescope using a range of radioactive sources. These images were aimed at assessing the performance of the telescope and included combinations of point sources, extended sources, ring sources as well as vignetted sources. Besides linear reconstruction techniques a range of non linear image restoration processes are discussed

1987-01-01

114

Susceptibility of selected potato varieties to zebra chip potato disease  

Science.gov (United States)

Zebra chip (ZC), an emerging and serious disease of potato has caused millions of dollars in losses to the potato industry in the United States, Mexico, Central America, and New Zealand. The disease has recently been associated with a previously undescribed species of liberibacter tentatively named ...

115

ZEBRA, the first stage of an accelerator breeder program  

International Nuclear Information System (INIS)

[en] It may be essential to have an option in the future that could supply some of the fissile fuel requirements for nuclear power stations operating on advanced fuel cycles. An option that looks attractive technologically is the accelerator breeder. Research and development work associated with an accelerator breeder program has been underway at Chalk River Nuclear Laboratories for a number of years. Most of the activities have been directed towards the development of the technology required for suitable high-current, high-energy linear accelerators. The rationale for an accelerator breeder development program involving four stages is described along with associated economics and design optimization. A staged development program permits periodic reviews in the light of technological developments and future considerations, including social, political and economic factors. A description of each stage and the opportunities available for research and development are given. The first stage, a 300 mA - 10 MeV proton linac, ZEBRA (Zero Energy BReeder Accelerator), is described in more detail including the status of siting the ZEBRA project at a new laboratory in Quebec. Prior to construction of ZEBRA, a number of pre-ZEBRA activities are underway in the accelerator and the target/blanket areas. These activities are described in relation to the overall program goals

1983-06-15

116

REGIONAL SUSCEPTIBILITY OF NORTHEAST LAKES TO ZEBRA MUSSEL INVASION  

Science.gov (United States)

The rapid spread of the exotic zebra mussel (Dreissena polymorpha) concerns aquatic resource managers in the United States and Canada. ince 1990 it has been spreading from the Great Lakes into the Northeast. he primary goal of this study is to provide lake resource managers in th...

117

The archaeology of the mountain Zebra National Park  

Directory of Open Access Journals (Sweden)

Full Text Available Thirty archaeological sites were located during a survey of the Mountain Zebra National Park. These include three-small rock shelters and 27 open station sites. The artefact samples collected from two of the latter are discussed in detail.

Mary Brooker

1977-01-01

118

Heart synchronization for SPIM microscopy of living zebra fish  

Science.gov (United States)

We describe work on producing a selective plane illumination microscope for cardiac imaging in zebra fish embryos. The system has a novel synchronization system for imaging oscillating structures (e.g. the heart) and will have adaptive optics for image optimization.

Taylor, J. M.; Saunter, C. D.; Chaudhry, B.; Henderson, D. J.; Love, G. D.; Girkin, J. M.

2011-02-01

119

A simple index of habitat suitability for Cape mountain zebras  

Directory of Open Access Journals (Sweden)

Full Text Available An index of habitat suitability for Cape mountain zebras was calculated using two parameters: acceptability indices for different grass species, and the aerial cover of the grass species in the habitat. The index was tested by calculating its value for a range of different habitat patches and comparing this with the frequency of use of the patches by zebras. The close relationship between the index and the observed frequency of use verified that the index could be used as a guide to habitat suitability. Two methods were used to determine the frequency of use of the patches: counts of faecal pellet groups and frequency of sightings. Both methods yielded similar results but the pellet group counts were less time- consuming and expensive. It is recommended that the index of habitat suitability be used (i) as a parameter for monitoring of long-term changes in habitat suitability in the Mountain Zebra National Park and (ii) as a guide for selecting appropriate areas to re- introduce mountain zebras.

P. Novellie; A. Winkle

1993-01-01

120

Analysis of CR1 Repeats in the Zebra Finch Genome  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Most bird species have smaller genomes and fewer repeats than mammals. Chicken Repeat 1 (CR1) repeat is one of the most abundant families of repeats, ranging from ~133,000 to ~187,000 copies accounting for ~50 to ~80% of the interspersed repeats in the zebra finch and chicken genomes, respectively....

George E. Liu; Yali Hou; Twain Brown

 
 
 
 
121

Operations with FORTRAN dynamic memory: the ZEBRA system and its predecessors  

International Nuclear Information System (INIS)

[en] A comparative review of the most popular programs in FORTRAN used for data processing in high energy physics, is presented. The system of dynamic memory ZEBRA developed in CERN for ES computers is described. The ZEBRA system can be used for any applications which require manipulations with considerable volumes of data with nontrivial internal bonds. The possibility of using the ZEBRA system when developing the systems of data acquisition operating in real time is envisaged. 6 refs.; 5 figs

1989-01-01

122

Effects of zebra mussels on a native amphipod and the invasive Dikerogammarus villosus : the influence of biodeposition and structural complexity  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the last decades, zebra mussels (Dreissena polymorpha) have invaded many freshwater systems with severe consequences for entire communities. Most benthic macroinvertebrates, especially amphipods and chironomids, increase in abundance in the presence of zebra mussels. Increased structural complexi...

Gergs, René; Rothhaupt, Karl-Otto

123

Electric utility Zebra Mussel Control technology conference: Proceedings  

Energy Technology Data Exchange (ETDEWEB)

This Conference on Zebra Mussel Control technology was held on October 22--23, 1991 in Itasca (Chicago), Illinois. The Conference was sponsored by EPRI Zebra Mussel Task Force and hosted by Commonwealth Edison Company to bring together representatives of utilities, manufacturers, researches, and consultants. Nineteen papers were presented in three sessions. These sessions were devoted to the following topics: Overview and Control Strategy, Monitoring and Non-Chemical Control Technology, and Chemical Control Technology. A half-day workshop/panel discussion devoted to the same topics was conducted at the second day of the formal presentations. More than 160 people attended this Conference. This report contains technical papers and summaries of the workshop/panel sessions. Of these 19 papers, there are 4 papers related to overview and control strategy, 7 papers related to monitoring and non-chemical control technology, and 8 papers related to chemical control technology.

Tsou, J.L. (ed.) (Electric Power Research Inst., Palo Alto, CA (United States)); Mussalli, Y.G. (Stone and Webster Environmental Services, Boston, MA (United States))

1992-03-01

124

Colour preferences in nest-building zebra finches.  

Science.gov (United States)

Some bird species are selective in the materials they choose for nest building, preferring, for example, materials of one colour to others. However, in many cases the cause of these preferences is not clear. One of those species is the zebra finch, which exhibits strong preferences for particular colours of nest material. In an attempt to determine why these birds strongly prefer one colour of material over another, we compared the preferences of paired male zebra finches for nest material colour with their preferences for food of the same colours. We found that birds did indeed prefer particular colours of nest material (in most cases blue) but that they did not generally prefer food of one colour over the other colours. It appears, then, that a preference for one colour or another of nest material is specific to the nest-building context. This article is part of a Special Issue entitled: insert SI title. PMID:23860278

Muth, Felicity; Steele, Matthew; Healy, Susan D

2013-07-13

125

Ion source development and injector design for ZEBRA  

International Nuclear Information System (INIS)

[en] The requirement for high and variable current in ZEBRA, and the acceptance limits (on both energy and phase space distribution) of the RFQ place stringent demands on the injector design. For variable current, the ion source extraction voltage must be varied over a wide range to maintain a matched beam, however the RFQ has a limited range of injection energy. The 75 keV injection energy made necessary by current limits in the RFQ will require that care be taken to ensure reliability. Beam spill limits in downstream structures and RFQ beam dynamics require minimal beam halo and precise control of the phase space distribution. Following a discussion of these problems, and the approaches being taken at Chalk River to solve them, a conceptual design for the ZEBRA injector is presented

1981-10-23

126

Rope can help with early detection of zebra mussels  

Energy Technology Data Exchange (ETDEWEB)

Many of the waters in the western US meet all the ecological requirements of suitable habitat for zebra mussels, which can spread to new bodies of water by attaching to boats. With that in mind, Reclamation has launched Zebra Mussel Watch, a program aimed at early detection of the mussel in western waters. As part of the watch program, Reclamation suggests attaching one end of a rope to a weight such as a brock, rick, or cinder block, and placing the weight in shallow water to detect the arrival of zebra mussels. Any kind of rope will do, but nylon is preferred because small mussels are easier to distinguish on nylon's smooth surface than on ropes with rough surfaces. Young mussels smaller than the head of a common straight pin are transparent when they first settle and probably will not be visible to the naked eye for several weeks, when they are larger and they take on the appearance of small, dark-colored clams. [Note: over time, algae, bacteria, and debris will cause the rope to darken. So the color of the rope used doesn't make much difference.] Hang a rope in 8 feet or less of well-oxygenated water where wave action will not move the bottom of the rope to any great degree. (Zebra mussels like slow currents and will not attach where the current is moving 4 to 5 feet per second or faster.) Leave the rope in the water two or three weeks to allow microorganisms to grow on it. Young mussels will settle on surfaces that are coated with algae and other microscopic organisms. Then, at two- to three-week intervals, lift the rope and examine it for young mussels. If adults are around, the young eventually will show up. Reclamation believes that by detecting the first arrival of the mussels, it can implement plans to control the spread of the mussels and alert nearby projects to the approaching menace.

McNabb, C.

1993-06-01

127

Nicotine kinetics in zebra finches in vivo and in vitro.  

UK PubMed Central (United Kingdom)

Nicotine enhances cognitive performance, and in the zebra finch (Taeniopygia guttata), which is a well-established model of cognition, the effects of nicotine on song production have been reported. Nicotine and cotinine plasma levels were assessed in vivo after subcutaneous injection of 0.18 mg/kg nicotine, a dose that elicits changes in song production. The half-life of nicotine elimination was 33 minutes, and levels were undetectable by 4 hours. Average plasma nicotine over 2 hours was 32 ng/ml, similar to levels seen in human smokers and rat models of nicotine behavior. Nicotine brain levels were 30 and 14 ng/g 1 and 2 hours after treatment. To understand the potential for drug interactions and the regulation of nicotine metabolism in zebra finches, we characterized in vitro nicotine metabolism and the hepatic enzyme involved. In humans, cytochrome P450 2A6 metabolizes nicotine to cotinine, and CYP2A-like activity and protein have been reported in some birds. Zebra finch liver microsomes metabolized nicotine and bupropion (a CYP2B substrate) but not coumarin (a CYP2A substrate). Nicotine was metabolized to cotinine with a Michaelis-Menten constant (K(m)) of 96 µM and a V(max) of 56 pmol/min per milligram. Nicotine and bupropion metabolism was inhibited by C-8-xanthate (a specific CYP2B inhibitor) but not by CYP2A-specific inhibitors, and hepatic levels of CYP2B-like but not CYP2A-like proteins correlated with nicotine (r = 0.52; P = 0.04) and bupropion metabolism (r = 0.81; P < 0.001), suggesting CYP2B-mediation of nicotine metabolism as seen in rats. These results will facilitate further investigation of nicotine's effects in zebra finches.

Miksys S; Cappendijk SL; Perry WM; Zhao B; Tyndale RF

2013-06-01

128

A phytosociological reconnaissance of the Mountain Zebra National Park  

Directory of Open Access Journals (Sweden)

Full Text Available The vegetation of the Mountain Zebra National Park, situated within the Eastern Mixed Karooveld of the Republic of South Africa, was surveyed and analysed according to the Braun-Blanquet phytosociological method of sampling and synthesis. Brief discussions on the phytogeography of the Karoo and the physiography and climate of the Park are included. Three distinct major vegetation types are described floristically, physiognomically and ecologically. A vegetation map of the Park is provided.

P. T van der Walt

1980-01-01

129

Nicotine kinetics in zebra finches in vivo and in vitro.  

Science.gov (United States)

Nicotine enhances cognitive performance, and in the zebra finch (Taeniopygia guttata), which is a well-established model of cognition, the effects of nicotine on song production have been reported. Nicotine and cotinine plasma levels were assessed in vivo after subcutaneous injection of 0.18 mg/kg nicotine, a dose that elicits changes in song production. The half-life of nicotine elimination was 33 minutes, and levels were undetectable by 4 hours. Average plasma nicotine over 2 hours was 32 ng/ml, similar to levels seen in human smokers and rat models of nicotine behavior. Nicotine brain levels were 30 and 14 ng/g 1 and 2 hours after treatment. To understand the potential for drug interactions and the regulation of nicotine metabolism in zebra finches, we characterized in vitro nicotine metabolism and the hepatic enzyme involved. In humans, cytochrome P450 2A6 metabolizes nicotine to cotinine, and CYP2A-like activity and protein have been reported in some birds. Zebra finch liver microsomes metabolized nicotine and bupropion (a CYP2B substrate) but not coumarin (a CYP2A substrate). Nicotine was metabolized to cotinine with a Michaelis-Menten constant (K(m)) of 96 µM and a V(max) of 56 pmol/min per milligram. Nicotine and bupropion metabolism was inhibited by C-8-xanthate (a specific CYP2B inhibitor) but not by CYP2A-specific inhibitors, and hepatic levels of CYP2B-like but not CYP2A-like proteins correlated with nicotine (r = 0.52; P = 0.04) and bupropion metabolism (r = 0.81; P zebra finches. PMID:23530019

Miksys, Sharon; Cappendijk, Susanne L T; Perry, William M; Zhao, Bin; Tyndale, Rachel F

2013-03-25

130

Zebra mussel control using periodic chlorine dioxide treatments  

Energy Technology Data Exchange (ETDEWEB)

This paper summarizes the EPRI report (TR-105202) on the same topic as well as presents changes in current thinking on the suitability (applicability) of chlorine dioxide for fouling control. Chlorine dioxide was tested as a zebra mussel biocide at two steam electric generating stations in Illinois and one in Indiana. The purpose of these studies was to determine the efficacy of chlorine dioxide in killing zebra mussels and to develop site specific treatment programs for the three utilities. The Electric Power Research Institute (EPRI) Zebra Mussel Consortium sponsored the testing of this recent use of chlorine dioxide. The raw water system at Central Illinois Public Service`s Meredosia Station, on the Illinois River, received applications of chlorine dioxide in April, July, and September 1994. The raw water system at Illinois Power Company`s Wood River Station, on the Mississippi River, received applications in July 1993, January, April, May, July, and September 1994. The Gallagher Station, on the Ohio River, was treated in July and October 1994. Chlorine dioxide was generated on-site and injected into the water intake structure. Both cooling and service water systems were treated at the facilities. 6 refs., 13 figs.

Tsou, J. [Electric Power Research Institute, Palo Alto, CA (United States); Coyle, J. [Central Illinois Public Service, Merdosia, IL (United States); Crone, D. [Illinois Power Company, Alton, IL (United States)] [and others

1996-08-01

131

On Polarization of the Zebra Pattern in Solar Radio Emission  

Science.gov (United States)

The problem of strong polarization of the zebra-type fine structure in solar radio emission is discussed. In the framework of the plasma mechanism of radiation at the levels of the double plasma resonance, the polarization of the observed radio emission may be due to a difference in rates of plasma wave conversion into ordinary and extraordinary waves or different conditions of escaping of these waves from the source. In a weakly anisotropic plasma which is a source of the zebra-pattern with rather large harmonic numbers, the degree of polarization of the radio emission at twice the plasma frequency originating from the coalescence of two plasma waves is proportional to the ratio of the electron gyrofrequency to the plasma frequency, which is a small number and is negligible. Noticeable polarization can therefore arise only if the observed radio emission is a result of plasma wave scattering by ions (including induced scattering) or their coalescence with low-frequency waves. In this case, the ordinary mode freely leaves the source, but the extraordinary mode gets into the decay zone and does not exit from the source. As a result, the outgoing radio emission can be strongly polarized as the ordinary mode. Possible reasons for the polarization of the zebra pattern in the microwave region are discussed.

Zlotnik, E. Y.; Zaitsev, V. V.; Altyntsev, A. T.

2013-05-01

132

Laterality of suckling behaviour in three zebra species.  

UK PubMed Central (United Kingdom)

Although side preference while suckling is an easily characterised lateralised behaviour, few studies have been conducted. We observed laterality in suckling behaviour in three captive zebra species to test two hypotheses: laterality affected by the foal (motor laterality) and laterality affected by the mother. In total we observed 35 foals of Grevy's, plains, and mountain zebra in two zoos and recorded 5128 successful suckling bouts and 9095 unsuccessful suckling attempts. At the population level the only factor affecting side preference of suckling bouts and attempts was the identity of the individual foal. Ten foals showed individual preferences: seven foals preferred suckling from the left side of the mother, three preferred suckling from the right side of the mother. The individual preferences increased with increasing age of the foal. Only one foal was refused more often from the opposite side than the preferred side used for suckling whereas three other foals were refused from the preferred side. Foals that preferred suckling either from left or right side were refused by the mare more often than foals which showed non-preference. Thus lateral preferences in suckling behaviour of zebra foals seem to be in line with the motor laterality hypotheses.

Pluhá?ek J; Olléová M; Bartošová J; Pluhá?ková J; Bartoš L

2013-05-01

133

Analysis of CR1 Repeats in the Zebra Finch Genome  

Directory of Open Access Journals (Sweden)

Full Text Available Most bird species have smaller genomes and fewer repeats than mammals. Chicken Repeat 1 (CR1) repeat is one of the most abundant families of repeats, ranging from ~133,000 to ~187,000 copies accounting for ~50 to ~80% of the interspersed repeats in the zebra finch and chicken genomes, respectively. CR1 repeats are believed to have arisen from the retrotransposition of a small number of master elements, which gave rise to multiple CR1 subfamilies in the chicken. In this study, we performed a global assessment of the divergence distributions, phylogenies, and consensus sequences of CR1 repeats in the zebra finch genome. We identified and validated 34 CR1 subfamilies and further analyzed the correlation between these subfamilies. We also discovered 4 novel lineage-specific CR1 subfamilies in the zebra finch when compared to the chicken genome. We built various evolutionary trees of these subfamilies and concluded that CR1 repeats may play an important role in reshaping the structure of bird genomes.

George E. Liu; Yali Hou; Twain Brown

2013-01-01

134

Heterospecific discrimination of Poecile vocalizations by zebra finches (Taeniopygia guttata).  

UK PubMed Central (United Kingdom)

Previous perceptual research with black-capped and mountain chickadees has demonstrated that the D note of the namesake chick-a-dee call controlled species-based discrimination compared to other note types in this call. In the current experiment, we sought to determine whether discrimination performance of the chickadees was controlled by stimulus-specific properties or due to learning through experience. To accomplish this, we tested zebra finches, a songbird species that is distantly related to chickadees, and also unfamiliar with black-capped and mountain chickadee vocalizations, on the same species-based discrimination on which black-capped and mountain chickadees were previously trained. We found that zebra finches learned the discrimination in the fewest number of trials with the D note, compared to other note types (i.e., the A, B, and C notes). In addition, we compared the current results to earlier work and found that zebra finches learned the discrimination in fewer trials compared to black-capped chickadees, and, across all species, males learned the discrimination in fewer trials than females. We discuss the roles that acoustic complexity and learning play in classification of the three species of songbirds tested. More generally, these results point to the benefits derived from testing members of each sex in species that vary in their natural history, vocal output, and phylogenetic relatedness as a means to uncover the mechanisms underlying acoustic communication. (PsycINFO Database Record (c) 2013 APA, all rights reserved).

Guillette LM; Hoeschele M; Hahn AH; Sturdy CB

2013-08-01

135

Heterospecific discrimination of Poecile vocalizations by zebra finches (Taeniopygia guttata).  

Science.gov (United States)

Previous perceptual research with black-capped and mountain chickadees has demonstrated that the D note of the namesake chick-a-dee call controlled species-based discrimination compared to other note types in this call. In the current experiment, we sought to determine whether discrimination performance of the chickadees was controlled by stimulus-specific properties or due to learning through experience. To accomplish this, we tested zebra finches, a songbird species that is distantly related to chickadees, and also unfamiliar with black-capped and mountain chickadee vocalizations, on the same species-based discrimination on which black-capped and mountain chickadees were previously trained. We found that zebra finches learned the discrimination in the fewest number of trials with the D note, compared to other note types (i.e., the A, B, and C notes). In addition, we compared the current results to earlier work and found that zebra finches learned the discrimination in fewer trials compared to black-capped chickadees, and, across all species, males learned the discrimination in fewer trials than females. We discuss the roles that acoustic complexity and learning play in classification of the three species of songbirds tested. More generally, these results point to the benefits derived from testing members of each sex in species that vary in their natural history, vocal output, and phylogenetic relatedness as a means to uncover the mechanisms underlying acoustic communication. (PsycINFO Database Record (c) 2013 APA, all rights reserved). PMID:23106805

Guillette, Lauren M; Hoeschele, Marisa; Hahn, Allison H; Sturdy, Christopher B

2012-10-29

136

ZEBRA - the sodium/metal chloride ceramic battery  

Energy Technology Data Exchange (ETDEWEB)

The Zebra development work has not been constrained by safety and other problems and construction of cells and batteries has proved simpler than similar sodium sulphur batteries. Development work is still required in some areas such as improved hermetic seals and calendar life and normal cycle life tests obviously have not yet reached the level achieved by some sodium sulphur developers. Accelerated cycling tests on Zebra cells have shown that there is no loss in capacity or increase in resistance at rates appropriate for low earth orbit satellites (16 cycles/day) up to 1500 cycles. These tests are continuing and characteristic life at these rates is as good as the obtained from sodium sulphur cells. The Zebra Battery has reached the stage where final optimization for the required applications is needed and engineering development is now required for development of production processes and detailed production costing. This new battery should revive the spirits of the electric vehicle campaigners and load levelling advocates who have waited too long for an advanced battery.

Tilley, A.R.; Wedlake, R.J.

1987-10-01

137

Evaluation of zebra mussels (Dreissena polymorpha) as biomonitors of mercury contamination in aquatic ecosystems.  

UK PubMed Central (United Kingdom)

Zebra mussels have invaded many lakes in the United States and could be a useful tool for monitoring responses of aquatic biota to changes in mercury loading. The goal of the present study was to evaluate zebra mussels for use as a biomonitor of mercury contamination by comparing zebra mussel mercury concentrations between a lake with only indirect atmospheric mercury contamination (Otisco Lake, NY, USA) and a lake that was directly contaminated by mercury discharges (Onondaga Lake, NY, USA). Zebra mussels were sampled in both the spring and fall of 2004 and 2005. Total mercury (THg) concentrations in zebra mussels were approximately seven times greater in Onondaga Lake than in Otisco Lake, and water column mercury concentrations differed by an order of magnitude between the two lakes. Seasonal differences resulted in significantly higher zebra mussel THg concentrations during the fall for both lakes. There was also significant variation among different sampling sites in Onondaga Lake. Mussel methylmercury concentrations averaged 53% of THg concentrations but were highly variable. Strong relationships between water column THg and zebra mussel THg suggest that zebra mussels are a good indicator of aquatic mercury concentrations and could be used as an effective biomonitor of mercury contamination in aquatic ecosystems.

Blackwell BD; Driscoll CT; Spada ME; Todorova SG; Montesdeoca MR

2013-03-01

138

Predation and physical environment structure the density and population size structure of zebra mussels  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The zebra mussel (Dreissena polymorpha) provides one example of successful invaders in novel environments. However, little attention has been devoted to exploring the factors regulating zebra mussel density and population size structure at the local scale. We tested effects of physicochemical factor...

Naddafi, Rahmat; Pettersson, Kurt; Eklöv, Peter

139

Quantitative genetics research in Zebra Finches: where we are and where to go  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The ease with which Zebra Finches can be kept and bred in captivity makes them a suitable model for avian quantitative genetic studies. After a brief introduction to some quantitative genetic concepts, we here provide an up-to-date overview of quantitative genetic studies in Zebra Finches. We discus...

Tschirren, B; Postma, E

140

WINTOF - A program to produce neutron spectra from Zebra time-of-flight experiments  

International Nuclear Information System (INIS)

This report describes a computer program, written for the Winfrith KDF9 computer, which is used to calculate the neutron energy spectrum in the Zebra reactor from neutron time-of-flight measurements using the Zebra Linac. The data requirements for the program are specified and an illustration of the final spectrum is included. (author)

1969-01-01

 
 
 
 
141

Predation on Zebra Mussels ('Dreissena polymorpha') by Common Carp ('Cyprinus carpio'). Long Term Resource Monitoring Program.  

Science.gov (United States)

The authors examined the gut contents of 31 common carp (Cyprinus carpio) collected at Mississippi River Mile 217 in August 1995 for evidence of predation on zebra mussels (Dreissena polymorpha). They found between 1 and 407 zebra mussel beaks in 83.9% of...

J. K. Tucker F. A. Cronin D. W. Soergel C. H. Theiling

1997-01-01

142

DNA adduct measurements in zebra mussels, Dreissena polymorpha, Pallas  

International Nuclear Information System (INIS)

[en] The purpose of this study was to examine PAH accumulation and bulky DNA adduct formation in the digestive gland of zebra mussels exposed in their habitat or in controlled laboratory conditions to complex mixture of PAH. DNA adducts were measured using a 32P-postlabelling protocol with nuclease P1 enrichment adapted from Reddy and Randerath [Reddy, M.V., Randerath, K., 1986. Nuclease P1-mediated enhancement of sensitivity of 32P-postlabelling test for structurally diverse DNA adducts. Carcinogenesis 7, 1543-1551]. Specimens collected in the upper part of the Seine estuary were shown to accumulate higher levels of PAH (up to 1.6 ?g g-1 dry weight) in comparison to individuals from the reference site (0.053 ?g g-1 dry weight). The former exhibited elevated levels of DNA adducts (up to 4.0/108 nucleotides) and higher diversity of individual adducts with five distinct spots being specifically detected in individuals originating from the Seine estuary. Zebra mussels exposed for 5 days to 0.01% (v/v) of organic extract of sediment from the Seine estuary were shown to accumulate high amounts of PAH (up to 138 ?g g-1 dry weight) but exhibited relatively low levels of DNA adducts. Exposure to benzo[a]pyrene led to a dose-dependent accumulation of B[a]P (up to 7063 ?g g-1 dry weight) and a clear induction of DNA adduct formation in the digestive gland of mussels (up to 1.13/108 nucleotides). Comparisons with other bivalves exposed to the same model PAH, revealed similar levels of adducts and comparable adduct profiles with a main adduct spot and a second faint one. This study clearly demonstrated that zebra mussels are able to biotransform B[a]P and probably other PAH into reactive metabolites with DNA-binding activity. This work also demonstrated the applicability of the nuclease P1 enhanced 32P-postlabelling method for bulky adduct detection in the digestive gland of zebra mussels. DNA adduct measurement in zebra mussels could be a suitable biomarker to monitor PAH-exposure and evaluate genotoxicity in fresh water ecosystems

2006-08-12

143

DNA adduct measurements in zebra mussels, Dreissena polymorpha, Pallas  

Energy Technology Data Exchange (ETDEWEB)

The purpose of this study was to examine PAH accumulation and bulky DNA adduct formation in the digestive gland of zebra mussels exposed in their habitat or in controlled laboratory conditions to complex mixture of PAH. DNA adducts were measured using a {sup 32}P-postlabelling protocol with nuclease P1 enrichment adapted from Reddy and Randerath [Reddy, M.V., Randerath, K., 1986. Nuclease P1-mediated enhancement of sensitivity of {sup 32}P-postlabelling test for structurally diverse DNA adducts. Carcinogenesis 7, 1543-1551]. Specimens collected in the upper part of the Seine estuary were shown to accumulate higher levels of PAH (up to 1.6 {mu}g g{sup -1} dry weight) in comparison to individuals from the reference site (0.053 {mu}g g{sup -1} dry weight). The former exhibited elevated levels of DNA adducts (up to 4.0/10{sup 8} nucleotides) and higher diversity of individual adducts with five distinct spots being specifically detected in individuals originating from the Seine estuary. Zebra mussels exposed for 5 days to 0.01% (v/v) of organic extract of sediment from the Seine estuary were shown to accumulate high amounts of PAH (up to 138 {mu}g g{sup -1} dry weight) but exhibited relatively low levels of DNA adducts. Exposure to benzo[a]pyrene led to a dose-dependent accumulation of B[a]P (up to 7063 {mu}g g{sup -1} dry weight) and a clear induction of DNA adduct formation in the digestive gland of mussels (up to 1.13/10{sup 8} nucleotides). Comparisons with other bivalves exposed to the same model PAH, revealed similar levels of adducts and comparable adduct profiles with a main adduct spot and a second faint one. This study clearly demonstrated that zebra mussels are able to biotransform B[a]P and probably other PAH into reactive metabolites with DNA-binding activity. This work also demonstrated the applicability of the nuclease P1 enhanced {sup 32}P-postlabelling method for bulky adduct detection in the digestive gland of zebra mussels. DNA adduct measurement in zebra mussels could be a suitable biomarker to monitor PAH-exposure and evaluate genotoxicity in fresh water ecosystems.

Le Goff, J. [GRECAN, UPRES EA-1772, University of Caen, Caen (France); Gallois, J. [Laboratory F. Duncombe, Conseil General du Calvados, Caen (France); Pelhuet, L. [LPTC, UMR-5472 CNRS, University Bordeaux I, Bordeaux (France); Devier, M.H. [LPTC, UMR-5472 CNRS, University Bordeaux I, Bordeaux (France); Budzinski, H. [LPTC, UMR-5472 CNRS, University Bordeaux I, Bordeaux (France); Pottier, D. [GRECAN, UPRES EA-1772, University of Caen, Caen (France); Andre, V. [GRECAN, UPRES EA-1772, University of Caen, Caen (France); Cachot, J. [LEMA, UPRES EA-3222, IFRMP 23, University of Le Havre, 25 rue Philippe Lebon, B.P. 540, 76058 Le Havre Cedex (France)]. E-mail: jerome.cachot@univ-lehavre.fr

2006-08-12

144

The use of positive reinforcement in training zebra sharks (Stegostoma fasciatum).  

UK PubMed Central (United Kingdom)

Positive reinforcement training (PRT) was used on 4 adult zebra sharks, Stegostoma fasciatum, housed at the Downtown Aquarium, Denver, to determine the ability of zebra sharks to become desensitized to various stimuli associated with veterinary procedures. One male and 3 female sharks were trained for 12 weeks. As a result of PRT, all 4 zebra sharks were desensitized to staying within a closed holding tank off of the main exhibit, the presence of multiple trainers in the closed holding tank, and tactile stimulation. One of the 4 zebra sharks was also successfully desensitized to the presence of a stretcher being brought into the holding tank. All of these procedures are common in veterinary examinations, and it is hoped that desensitization to these stimuli will reduce the stress associated with examinations. The training accomplished has allowed for easier maintenance of the zebra sharks by the aquarium staff and an improvement in the care of the sharks.

Marranzino A

2013-07-01

145

Zebra mussel filtration and its potential uses in industrial water treatment.  

UK PubMed Central (United Kingdom)

The zebra mussel (Dreissena polymorpha) is a notorious freshwater biofouling pest, and populations of the species can alter aquatic environments through their substantial filtration capabilities. Despite the ecological importance of zebra mussel filtration, many predictions of their large-scale effects on ecosystems rely on extrapolations from filtration rates obtained in static laboratory experiments, not accounting for natural mussel densities, boundary layer effects, flow rates or elevated algal concentrations. This study used large-scale industrial flume trials to investigate the influence of these factors on zebra mussel filtration and proposes some novel industrial applications of these findings. The flume trials revealed some of the highest zebra mussel clearance rates found to date, up to 574+/-20mlh(-1)g(-1) of wet tissue mass. Under low algal concentrations, chlorophyll a removal by zebra mussels was not proportional to mussel density, indicating that field rates of zebra mussel grazing may be much lower than previous studies have predicted. Increasing ambient velocities up to 100mls(-1) ( approximately 4cms(-1)) led to increased clearance rates by zebra mussels, possibly due to the replenishment of locally depleted resources, but higher velocities of 300mls(-1) (12cms(-1)) did not lead to further significant increases in clearance rate. When additional algal cultures were dosed into the flumes, chlorophyll a removal increased approximately logarithmically with zebra mussel density and there were no differences in the clearance of three different species of alga: Ankyra judayi, Pandorina morum and Cyclotella meneghinia. Some novel industrial uses of these zebra mussel filtration studies are proposed, such as: (1) helping to inform models that predict the large-scale grazing effects of the mussels, (2) allowing estimates of zebra mussel densities in industrial pipelines, and (3) constructing large-scale biofilters for use in water clarification.

Elliott P; Aldridge DC; Moggridge GD

2008-03-01

146

Zebra mussel control using thermal treatment for electric utility stations  

Energy Technology Data Exchange (ETDEWEB)

When electric utilities and other water users on the Great Lakes were confronted with operating problems due to zebra mussels, Commonwealth Edison Company (ComEd) established a task force to develop a plan to counteract the threat at the ComEd electric generating stations. A monitoring program was initiated at the stations, and an evaluation of control options was started. At State Line Station, located on the southern tip of Lake Michigan, ComEd experimented with thermal treatment of the circulating water and service water systems. The station design allows recirculation of the cooling water with minimal modifications. The trial at State Line Station proved successful in controlling the zebra mussels with minimal impact on operations. Based on the successful trial and the task force`s assessment of other control options, ComEd determined that, for their fossil-fueled generating stations, thermal treatment was the most cost-effective approach, with the least impact on station operation and the environment. Of the 10 fossil-fueled generating stations operated by ComEd, 8 have been selected for modifications. The other 2 stations have not yet been affected by zebra mussels. Before performing detailed design, a study was performed for each station to evaluate the operation of the equipment at elevated temperature and to determine the operating limits needed at the target treatment temperature of 95 F. Conceptual designs for the modifications were developed, and the most cost-effective arrangement was selected for detailed design. Case studies of the modifications being constructed at several stations are presented. The modifications to the circulating water systems are described. Initial results of the treatment are reviewed.

Marcus, R.I. [Commonwealth Edison Co., Downers Grove, IL (United States); Wahlert, S.L. [Sargent and Lundy, Chicago, IL (United States)

1995-10-01

147

The effect of sodium chlorite solutions on zebra mussel mortality  

Energy Technology Data Exchange (ETDEWEB)

The effect of four dilutions, 8 ppm, 40 ppm, 120 ppm and 473 ppm of the stock solution of a first product, Z-8, on zebra mussel mortality was investigated in static continuous exposure systems and compared to controls. The entire size class spectrum of the mussel population present at the sampling site was tested by leaving mussels attached to their original rock substrata. Two size class grouping of mussels, 13 mm and less and more than 13 mm in length, were exposed in the same test chambers but were analyzed separately. No mortality occurred in the controls. Concentration 8 ppm had no effect after 166 hours on both size class groupings. Concentrations 40, 120 and 473 ppm had observable killing effect within the 331 hours of experiment for both size groupings. The smaller mussels died faster than the larger ones. Another product, Z-11, was similarly tested during fall 1994 with dilutions 8, 40, 80 and 120 ppm. At 8 ppm dilution, Z-11 had induced only little mortality on both size class groupings after 739 hours. At 40, 80 and 120 ppm dilutions, Z-11 had interesting killing effect for both mussel size groupings within the 739 hours of experiment considering the somehow intermittent treatment used. The results already appear to show that sodium chlorite solutions have the potential for eventually becoming a surrogate to the use of chlorine for the control of zebra mussels. That is because they already show a good killing efficiency without being involved in the formation of undesired by-products such as the use of chlorine is. On this purpose, the product is engaged in the process of homologation by Agriculture Canada for it use as treatment against zebra mussels.

Dion, J.; Richer, Y. [Subdev Canada Inc., Ste-Julie, Quebec (Canada); Messer, R. [BiO2xy Incorporated, Raleigh, NC (United States)

1995-06-01

148

Digital gene expression analysis of the zebra finch genome  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background In order to understand patterns of adaptation and molecular evolution it is important to quantify both variation in gene expression and nucleotide sequence divergence. Gene expression profiling in non-model organisms has recently been facilitated by the advent of massively parallel sequencing technology. Here we investigate tissue specific gene expression patterns in the zebra finch (Taeniopygia guttata) with special emphasis on the genes of the major histocompatibility complex (MHC). Results Almost 2 million 454-sequencing reads from cDNA of six different tissues were assembled and analysed. A total of 11,793 zebra finch transcripts were represented in this EST data, indicating a transcriptome coverage of about 65%. There was a positive correlation between the tissue specificity of gene expression and non-synonymous to synonymous nucleotide substitution ratio of genes, suggesting that genes with a specialised function are evolving at a higher rate (or with less constraint) than genes with a more general function. In line with this, there was also a negative correlation between overall expression levels and expression specificity of contigs. We found evidence for expression of 10 different genes related to the MHC. MHC genes showed relatively tissue specific expression levels and were in general primarily expressed in spleen. Several MHC genes, including MHC class I also showed expression in brain. Furthermore, for all genes with highest levels of expression in spleen there was an overrepresentation of several gene ontology terms related to immune function. Conclusions Our study highlights the usefulness of next-generation sequence data for quantifying gene expression in the genome as a whole as well as in specific candidate genes. Overall, the data show predicted patterns of gene expression profiles and molecular evolution in the zebra finch genome. Expression of MHC genes in particular, corresponds well with expression patterns in other vertebrates.

Ekblom Robert; Balakrishnan Christopher N; Burke Terry; Slate Jon

2010-01-01

149

Biogeochemical alteration of the benthic environment by the zebra mussel Dreissena polymorpha (Pallas)  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of this study was to verify whether the biogeochemicalfeatures (e.g. concentration of nutrients, oxygen consumption,mineralization rate, Eh) of sediments changed by the zebra musselor its shell deposits differ from those in the ambient soft bottom,and how these differences are related to the structure of benthicmacroinvertebrates. In 2006 three sampling sessions were carriedout in the Curonian Lagoon, SE Baltic Sea, at three pre-definedsites, corresponding to different bottom types: zebra musselbed, zebra mussel shell deposits and bare soft sediments. Similarityanalysis of biogeochemical parameters indicated that bottom sedimentscovered with zebra mussel shell deposits were rather distinctfrom the other bottom types because of the lowest total organicmatter mineralization rate and highest organic carbon, totalphosphorus and total nitrogen content. The parameters measuredin the zebra mussel bed did not deviate conspicuously from thevalues observed in bare bottoms, except for the higher rate ofoxygen consumption in the upper sediment layer. Unsuitable anoxicconditions on the one hand and the "attractive" shelters providedby zebra mussels on the other hand may promote the epifaunallife style in the habitats formed by dense zebra mussel clumps.

Anastasija Zaiko; Ri?ardas Paškauskas; Alina Krevš

2010-01-01

150

Variation in tissue stoichiometry and condition index of zebra mussels in invaded Swedish lakes  

UK PubMed Central (United Kingdom)

We examined the spatial variation in carbon:nitrogen:phosphorus (C:N:P) stoichiometry and condition index of the zebra mussel (Dreissena polymorpha), non-indigenous species, in four Swedish lakes with different productivity. Within-lake variability was observed in tissue C:N molar ratios of Dreissena in all lakes and in tissue C:P ratio only in three lakes. Depth had no effect on tissue C:P and N:P ratios of Dreissena. A positive correlation was found between C:N:P stoichiometry of seston and elemental composition of zebra mussel in one of the lakes. Tissue C:N and N:P ratios were the main factors that related to zebra mussel condition index. Zebra mussel condition was positively related to tissue C:N ratio. Smaller Dreissena had higher C:N ratio than larger Dreissena in two of the four lakes. Zebra mussels in the lake with highest productivity had lower C:P and N:P ratios than zebra mussels in the lake with lowest productivity. Our study suggests that the zebra mussel may modify their phosphorus content in relation to lake trophic state, and therefore cope with stoichiometric constraints which may explain the invasion success of this and other related species.

Naddafi R; Goedkoop W; Grandin U; Eklöv P

2012-10-01

151

Developmental origins of mosaic brain evolution: Morphometric analysis of the developing zebra finch brain.  

Science.gov (United States)

In adult zebra finches (Taeniopygia guttata), the telencephalon occupies 64% of the entire brain. This fraction is similar to what is seen in parrots, but many other birds possess a significantly smaller telencephalon. The aim of the present study was to determine the developmental time course and cellular basis of telencephalic enlargement in zebra finches, and then to compare these findings with what is known about telencephalic enlargement in other birds. To this end we estimated the volumes of all major brain regions from serial sections in embryonic and post-hatching zebra finches. We also labeled proliferating cells with antibodies against proliferating cell nuclear antigen and phosphorylated histone H3. An important finding to emerge from this work is that the telencephalon of zebra finches at hatching contains a thick proliferative subventricular zone (SVZ) that extends from the subpallium into the dorsal pallium. The data also show that the onset and offset of telencephalic neurogenesis are both delayed in zebra finches relative to quail (Galliformes). This delay in neurogenesis, in conjunction with the expanded SVZ, probably accounts for most of the telencephalic enlargement in passerines such as the zebra finch. In addition, passerines enlarged their telencephalon by decreasing the proportional size of their midbrain tectum. Because the presumptive tectum is proportionally smaller in zebra finches than quail before neurogenesis begins, this difference in tectum size cannot be due to evolutionary alterations in neurogenesis timing. Collectively these findings indicate that several different developmental mechanisms underlie the evolution of a large telencephalon in passerines. PMID:19266567

Charvet, Christine J; Striedter, Georg F

2009-05-10

152

Factors Affecting Zebra Mussel Kill by the Bacterium Pseudomonas fluorescens  

Energy Technology Data Exchange (ETDEWEB)

The specific purpose of this research project was to identify factors that affect zebra mussel kill by the bacterium Pseudomonas fluorescens. Test results obtained during this three-year project identified the following key variables as affecting mussel kill: treatment concentration, treatment duration, mussel siphoning activity, dissolved oxygen concentration, water temperature, and naturally suspended particle load. Using this latter information, the project culminated in a series of pipe tests which achieved high mussel kill inside power plants under once-through conditions using service water in artificial pipes.

Daniel P. Molloy

2004-02-24

153

Zebra mussels anchor byssal threads faster and tighter than quagga mussels in flow.  

UK PubMed Central (United Kingdom)

While the invasive zebra mussel Dreissena polymorpha has rapidly spread throughout the Great Lakes and inland waterways, it is being displaced by the quagga mussel Dreissena bugensis in shallow water habitats. However, zebra mussels remain dominant in areas with higher water velocity. We hypothesized that the persistence of zebra over quagga mussels in habitats with higher water velocity might result from greater rate and strength of byssal thread attachment. We examined whether zebra mussels relative to quagga mussels have: (1) higher byssal thread synthesis rate, (2) lower dislodgment in flow and (3) greater mechanical force required for detachment from substrate. Specifically, we examined byssal thread synthesis rate and dislodgment of both species in response to water velocities of 0, 50, 100 and 180 cm s(-1). Byssal thread synthesis rate was significantly higher for zebra than for quagga mussels at all velocities. Dislodgment from the substrate increased for both species with increasing velocity but was significantly lower for zebra than for quagga mussels. We also tested the mechanical force to detach mussels after short (32 h) and long (two and three months) periods of attachment on hard substrate. Detachment force was significantly higher for zebra than for quagga mussels only after short-term attachment. Higher byssal thread synthesis rate in zebra mussels was a likely factor that minimized their dislodgment in flow and increased short-term attachment strength. Differences in byssal thread synthesis rate between the two species might partly account for the ability of zebra mussels to maintain dominance over quagga mussels in habitats with high velocities.

Peyer SM; McCarthy AJ; Lee CE

2009-07-01

154

Experimental pathogenicity of aeromonas spp. for the zebra mussel, dreissena polymorpha  

UK PubMed Central (United Kingdom)

Experiments were conducted to determine whether species of Aeromonas were pathogenic to the zebra mussel Dreissena polymorpha. A. jandaei, A. veronii, and A. media, identified with Biolog, were originally isolated from dead zebra mussels. When inoculated into living mussels, these bacteria resulted in the mortality of the bivalves. Two additional species, A. salmonicida salmonicida (ATCC 33678) and A. hydrophila (ATCC 7966), were also demonstrated to be pathogenic to the mussels. In addition to the pathogenicity, the data also suggest that the zebra mussels may be an important reservoir for these bacteria in freshwater environments.

Maki JS; Patel G; Mitchell R

1998-01-01

155

Byssal proteins of the freshwater zebra mussel, Dreissena polymorpha.  

UK PubMed Central (United Kingdom)

The freshwater zebra mussel (Dreissena polymorpha) is a notorious biofouling organism. It adheres to a variety of substrata underwater by means of a proteinaceous structure called the byssus, which consists of a number of threads with adhesive plaques at the tips. The byssal proteins are difficult to characterize due to extensive cross-linking of 3,4-dihydroxyphenylalanine (DOPA), which renders the mature structure largely resistant to protein extraction and immunolocalization. By inducing secretion of fresh threads and plaques in which cross-linking is minimized, three novel zebra mussel byssal proteins were identified following extraction and separation by gel electrophoresis. Peptide fragment fingerprinting was used to match tryptic digests of several gel bands against a cDNA library of genes expressed uniquely in the mussel foot, the organ which secretes the byssus. This allowed identification of a more complete sequence of Dpfp2 (D. polymorpha foot protein 2), a known DOPA-containing byssal protein, and a partial sequence of Dpfp5, a novel protein with several typical characteristics of mussel adhesive proteins.

Gantayet A; Ohana L; Sone ED

2013-01-01

156

Characterization of zebra mussel transport near a pump intake  

Directory of Open Access Journals (Sweden)

Full Text Available The appearance and explosive population growth of zebra mussels have impacted many facilities near water, such as electricity-generating power plants. These mussels can congregate at plant-water-intake structures where proactive maintenance actions, such as mussel kills, must be performed. However, once dead, the mussel debris is a potential contaminant drawn into the plant via cooling water pump suctions; this may affect piping and components downstream of the pump suctions. Thus, it becomes necessary to establish whether sufficient water velocity, from the suction action of a pump, exists to entrain shell debris. Although entrainment data for zebra mussel shells and shell fragments are lacking, this study employs a generalized empirical method based on other types of bivalve shells. Basic pump-suction considerations yield an entrainment volumetric zone in which any shells would be drawn into the pump. A calculated sample zone extends slightly less than one meter from the centerline of the pump-suction pipe and is cylindricalin shape. This approach can be generalized to various pump intake configurations and bivalves, providing a predictive means for evaluating plant system contaminants. Experimental data, although outside the scope of this study, may be used to refinethe modeling.

R. A. Tatara; D. R. Poe; G. M. Lupia

2008-01-01

157

The zebra mussel: US utility implications. [Contains Glossary  

Energy Technology Data Exchange (ETDEWEB)

Dreissena polymorpha, the freshwater macrofouling zebra mussel, was introduced to Lake St. Clair, near Detroit, Michigan, in 1985. It has since spread throughout Lake Erie. Its planktonic veliger larval stage disperses on water currents and adults are transported by human and natural vectors, making it likely to spread throughout most of the United States and southern Canada except for the southwestern and southern United State, where summer water temperatures are above tolerated levels. Veligers enter raw water systems on intake currents to settle and grow to adults attached by secreted byssal threads to hard surfaces. Accumulations of adults impede flow, aggravate sedimentation and corrosion, and foul small-diameter components. Settlement occurs at flow velocities less than 1.5--2.0 m/sec. Mussels can reduce effective pipe diameters and foul intake structures, steam condensers, heat exchangers, fire protection systems, and cooling tower basins. Establishment of mussels in raw water systems should be prevented because subsequent removal is difficult and expensive. Mitigation procedures include manual removal, robotic cleaning, thermal backwashing, water jetting, application of molluscicides, and possibly line pigging and acidic chemical cleaning. Control technologies include oxidizing and non-oxidizing molluscicides, robotic cleaning, shell strainers, exposure of veligers to high voltage electrical fields, thermal backwashing and sand-filtration. The United States power industry can utilize extensive European experience with this species and domestic experience with the Asian clam in its development of effective controls for zebra mussel fouling.

McMahon, R.F. (Macrofouling Consultants, Arlington, TX (USA))

1990-11-01

158

Power improved ZEBRA Battery for zero emission vehicles  

Energy Technology Data Exchange (ETDEWEB)

The ZEBRA Battery is a high energy battery developed for powering a Zero Emission Vehicle (ZEV). The electrode materials used for production are salt (NaCl) and nickel (Ni) in combination with a ceramic electrolyte. During charging the salt is decomposed to sodium (Na) and nickel chloride (NiCl{sub 2}) is formed. During discharge salt is formed in the reverse reaction. This battery realizes an energy density of more than 90 Wh/kg which exceeds the USABC mid-term goals. These goals were set to achieve a ZEV with acceptable range and performance. The ZEBRA Battery has demonstrated the other USABC mid-term goals. 1.200 cycles in vehicle operation, more than 8 years in an accelerated calendar life test and recharge time of less than 6 hours. Due to the thermal management environmental conditions of {minus}30 C to +65 C do not cause any problems. In order to meet also the power and cost goals a program has been started. Two approaches for power improvement at 80% DOD show promising results: the geometric approach by increasing the surface area of the ceramic electrolyte and the chemical approach by additives to the cathode composition.

Dustmann, C.H.; Tilley, R.

1996-09-01

159

IRPHE-ZEBRA, AEEW Fast Reactor Experiments, Primary Documentation  

International Nuclear Information System (INIS)

[en] Description of program or function: ZEBRA, the zero energy breeder reactor assembly, was used to study the neutron physics of fast reactors (R D Smith, Nuclear Engineering Vol. 7 No. 76, Sept 1962, 'ZEBRA, a Zero Power Fast Reactor'). It operated from 1962 until 1982. Mock-up type assemblies representing PFR, Monju and the proposed European Fast Reactor, EFR, were studied, as well as simple assemblies for nuclear data validation. Some experiments were designed to validate the Methods used to treat the heterogeneity of the composition and to calculate control rods. Most ZEBRA assemblies were built using 2 inch square plates (51 mm square) stacked in stainless steel tubes, with the tubes, or elements, being located in holes in the reactor base plate. Blocks of 5x5 elements are grouped inside a mild steel superlattice and so the spacing of elements is not completely uniform. This size of plates was chosen to be compatible with the components in the ZPR facilities in Argonne National Laboratory and is also compatible with the MASURCA and SNEAK components, permitting these to be combined to build large assemblies. Mini-calandria containing sodium (or voided of sodium) and with uranium oxide and mixed uranium-plutonium oxide fuel in pin form (4x4 pins per mini-calandria) are also used in the later assemblies. The ZEBRA control rods use smaller components. In addition, special assemblies simulating power reactor control rods, rod followers and other singularities have been studied. These replace groups of elements. The compositions of the components are detailed in PLATEDATA. The arrangement of these components to form cells and the loading of the cells in elements and special assemblies is detailed in the documents listed below, together with the arrangement of the elements in the reactor. Control rod studies and sodium voiding studies have been carried out on several assemblies. Spectral indices, small sample reactivity worths and reaction rate distributions were measured on most assemblies. Neutron spectrum measurements have also been made on some assemblies. In the later assemblies a multi-chamber scanning system was used to measure fission rates at a large number of points in the core. Various simplifications were made in developing calculational models to analyse the measurements, although information is also provided giving the full details of the core loadings. Simplifications include corrections to replace the ZEBRA control rods by standard core elements and replacing the slightly different plutonium plates by a single one. These differences result in small differences in core height for the different elements and a correction is also made for this. In the earlier cores equivalent homogeneous compositions were derived and cylindrical (and even spherical) equivalent models derived. Later the plates were represented explicitly in the cell calculations used to derive homogeneous cell-averaged cross-sections for whole reactor calculations, including representation of the cladding materials (in a three dimensional, XYZ representation). NEA-1661/02: April 2006: this is the DVD version

160

Additions and amendments to the bird and mammal lists of the Mountain Zebra National Park  

Directory of Open Access Journals (Sweden)

Full Text Available The following account updates and amends various previous publications dealing with the birds and mammals of the Mountain Zebra National Park (MZNP). In the case of birds, Roberts' Birds of South Africa numbers are used.

J. H Grobler; P. J Bronkhorst

1981-01-01

 
 
 
 
161

Annotated Check List of the Spiders (Araneae) of the Mountain Zebra National Park  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A preliminary check list of the spider fauna of the Mountain Zebra National Park is given. Sixteen families, comprising 29 genera and 32 species, are recorded. Observations on the distribution, diagnostic morphology and behaviour of 15 species are given.

Anna S. Dippenaar-Schoeman

162

Zebra pattern in CT during arterial portography analysis of associated factors  

International Nuclear Information System (INIS)

[en] To analyze the factors associated with the zebra pattern in CT during arterial portography(CTAP). In 275 CTAP procedures, the factors associated with the zebra pattern, such as laminar flow in the portal vein, the presence of liver cirrhosis, the artery selected for CTAP, location of the catheter tip in the superior mesenteric artery(SMA), splenic volume, and the existence of an aberrant right hepatic artery(RHA) emerging from the SMA were analyzed. In 106 of 275 procedures (38.5%), a zebra pattern was apparent. Portal venous laminal flow was seen in 92% of procedures in the group with this pattern and in 63% in the group without it. Eighty-three of 235 procedures (35.3%) in which the SMA was injected and 23 of 40(57.5%) involving splenic artery injection showed the zebra pattern. In 22 of 35(62.8%) in which the catheter tip was located in the distal SMA and 61 of 200(30.5%) in which this was at a proximal site, the zebra pattern was evident. Mean splenic volume was less in the group with the zebra pattern. The effect on the zebra pattern of liver cirrhosis and an aberrant RHA emerging from the SMA was not statistically significant. In CTAP, the incidence of the zebra pattern was 38.6%, and was related to laminal flow in the portal vein. The pattern is frequently seen in CTAP involving contrast injection via the splenic artery, distal location of a catheter tip in the SMA, and small splenic volume

1999-01-01

163

Zebra pattern in CT during arterial portography analysis of associated factors  

Energy Technology Data Exchange (ETDEWEB)

To analyze the factors associated with the zebra pattern in CT during arterial portography(CTAP). In 275 CTAP procedures, the factors associated with the zebra pattern, such as laminar flow in the portal vein, the presence of liver cirrhosis, the artery selected for CTAP, location of the catheter tip in the superior mesenteric artery(SMA), splenic volume, and the existence of an aberrant right hepatic artery(RHA) emerging from the SMA were analyzed. In 106 of 275 procedures (38.5%), a zebra pattern was apparent. Portal venous laminal flow was seen in 92% of procedures in the group with this pattern and in 63% in the group without it. Eighty-three of 235 procedures (35.3%) in which the SMA was injected and 23 of 40(57.5%) involving splenic artery injection showed the zebra pattern. In 22 of 35(62.8%) in which the catheter tip was located in the distal SMA and 61 of 200(30.5%) in which this was at a proximal site, the zebra pattern was evident. Mean splenic volume was less in the group with the zebra pattern. The effect on the zebra pattern of liver cirrhosis and an aberrant RHA emerging from the SMA was not statistically significant. In CTAP, the incidence of the zebra pattern was 38.6%, and was related to laminal flow in the portal vein. The pattern is frequently seen in CTAP involving contrast injection via the splenic artery, distal location of a catheter tip in the SMA, and small splenic volume.

Hong, Suk Ju; Kim, Yun Hwan; Choi, Jae Woong; Sung, Deuk Je; Cho, Sung Bum; Kim, Chul Joong; Chung, Kyoo Byung; Suh, Won Hyuck [Anam Hospital, Korea Univ. College of Medicine, Seoul (Korea, Republic of)

1999-11-01

164

Status of Ontario Hydro R and D to control zebra mussels and mitigation strategies used  

Energy Technology Data Exchange (ETDEWEB)

To date, many different chemical and non-chemical techniques have been investigated for the control of zebra mussels, with the treatment of choice being based on chemical control in both Europe and North America. This is likely to change as environmental constraints on the release of chemicals into natural water bodies continues to increase. This paper describes the different mitigation measures used and those that are proposed for the control of zebra mussels in industrial systems, particularly power generating facilities.

Claudi, R.

1994-01-01

165

Zebra mussel adhesion: structure of the byssal adhesive apparatus in the freshwater mussel, Dreissena polymorpha.  

UK PubMed Central (United Kingdom)

The freshwater zebra mussel (Dreissena polymorpha) owes a large part of its success as an invasive species to its ability to attach to a wide variety of substrates. As in marine mussels, this attachment is achieved by a proteinaceous byssus, a series of threads joined at a stem that connect the mussel to adhesive plaques secreted onto the substrate. Although the zebra mussel byssus is superficially similar to marine mussels, significant structural and compositional differences suggest that further investigation of the adhesion mechanisms in this freshwater species is warranted. Here we present an ultrastructural examination of the zebra mussel byssus, with emphasis on interfaces that are critical to its adhesive function. By examining the attached plaques, we show that adhesion is mediated by a uniform electron dense layer on the underside of the plaque. This layer is only 10-20 nm thick and makes direct and continuous contact with the substrate. The plaque itself is fibrous, and curiously can exhibit either a dense or porous morphology. In zebra mussels, a graded interface between the animal and the substrate mussels is achieved by interdigitation of uniform threads with the stem, in contrast to marine mussels, where the threads themselves are non-uniform. Our observations of several novel aspects of zebra mussel byssal ultrastructure may have important implications not only for preventing biofouling by the zebra mussel, but for the development of new bioadhesives as well.

Farsad N; Sone ED

2012-03-01

166

Interpretation of experiments made in ZEBRA CADENZA assemblies with CEA formulary  

International Nuclear Information System (INIS)

A benchmark exercise on fast critical heterogeneity method assessment has been proposed in the framework of NEACRP. It is based on the analysis of two integral experiments performed by UKAEA on the ZEBRA facility (the CADENZA assemblies): - a plate fuelled core (ZEBRA 22); - a 75% pin fuelled core (ZEBRA 23). The interpretation of these experiments has been done using the current standard CEA methods. We find a relevant (650 pcm) discrepancy between the ''k'' values of ZEBRA 22 and ZEBRA 23 pin assemblies. We try in this report to find out the origin of this discrepancy. The spatial k-value calculation results and corrections are affected by nomore than 150 pcm and are partially correlated. Moreover, this discrepancy does not seem to be explained in terms of homogenous infinite dilute cross section effects. It has been found that most of the discrepancy can be traced back to heterogeneity effects, and mainly to the heterogeneity effects of the metallic fuel plate in the metallic fuel plate in the ZEBRA 22 cell. Finally, the pin core gives, in the CEA analysis, a Keff E-C value well inside the known performance of the adjusted CARNAVAL IV formulaire (i.e. E-C =+ 300 + +500+-200 pcm) for plutonium fuelled cores

1983-01-01

167

Safety and reliability of high energy batteries, using the example of the ZEBRA battery. Sicherheit und Zuverlaessigkeit von Hochenergiebatterien am Beispiel der ZEBRA-Batterie  

Energy Technology Data Exchange (ETDEWEB)

The ZEBRA battery is a battery system based on sodium and nickel chloride. The construction and method of operation of the system are described. Experiments show that if the battery breaks, no uncontrollable reactions occur. Due to the pair of nickel and sodium aluminium chloride electrodes, the battery has a 'built-in' overcharging protection. Under the heading of reliability, the points of thermal resistance, corrosion behaviour and electrical properties are examined. Overall, it is found that with the ZEBRA battery, a battery system is available which, in spite of high energy and output densities, is safe and reliable. (BWI)

Boehm, H. (Beta R and D, Derby (United Kingdom)); Sudworth, J.L. (Beta R and D, Derby (United Kingdom))

1993-01-01

168

IMPACT OF OXYGEN CONCENTRATION ON ZEBRA MUSSEL MORTALITY  

Energy Technology Data Exchange (ETDEWEB)

These tests have indicated that the bacterium Pseudomonas fluorescens strain CL0145A is effective at killing zebra mussels in environments having dissolved oxygen (DO) concentrations ranging from very low to very high. The results suggest that the highest mussel kill can be achieved in moderately to highly aerated environments, while kill may be 0-20% lower under conditions of very low oxygen. For example, under highly oxygenated conditions 97% kill was achieved while conditions having low DO produced 79% mussel kill. Service water measured in a local power plant indicated that DO concentrations were in the range of 8-9 ppm (e.g., highly aerated) within their pipes. Therefore, we will not expect to see decreases in the efficacy of CL0145A treatments due to oxygen levels within such power plant pipes.

Daniel P. Molloy

2003-01-27

169

Improving production of Zebra Fish Embryos in the lab  

DEFF Research Database (Denmark)

The utilization of fish embryos in toxicity testing of hazardous chemicals has recently been adopted in order to satisfy stricter rules and regulations related to using adult animals in toxicity testing. This paper presents optimising steps towards improving zebra fish embryo production in the laboratory. Culture conditions were maintained in the aquaria as stipulated in the OECD draft proposal for a new guideline on fish embryo tests. Furthermore, a sequence of steps were adopted and followed to improve upon previous work done in the lab in 2006. About 200 eggs were produced in one spawn trap within an hour of onset of light, an improvement over the 50-60 eggs produced in the previous work. This result demonstrates that with the right culture conditions and proper optimisation of procedure the required number of embryos needed for toxicity testing can be obtained.

Thomsen, Jens Peter; Adu, Robert Ohene

2011-01-01

170

Design and constraints for the ZEBRA injector, RFQ and DTL  

International Nuclear Information System (INIS)

[en] ZEBRA (Zero Energy Breeder Accelerator) is a proposed laboratory test accelerator designed to produce the full accelerator-breeder beam current of 300 mA at only 1% of the final energy of 1 GeV. Being an experimental prototype, it will be heavily instrumented to diagnose performance under conditions typical of the low energy portion of an accelerator breeder. It will consist of 3 sections - a dc injector, an RFQ buncher-preaccelerator, and a drift tube Alvarez linac. Several constraints are introduced by its eventual application as an injector for an accelerator breeder including variable beam current, economic accelerating gradients that will result in reliable operation, frequency choice and frequency multiplication between the RFQ and Alvarez linacs. This paper discusses the constraints and presents the rationale for the current reference design

1981-10-23

171

Floristic analysis of the Mountain Zebra National Park, Eastern Cape  

Directory of Open Access Journals (Sweden)

Full Text Available As part of a larger project to assess the vegetation dynamics and conservation potential of the enlarged Mountain Zebra National Park, a checklist was produced to determine the plant species richness for this area. Six hundred and eighty species, represented by 333 genera and 87 families were identified. One hundred and eighty species belong to the Monocotyledoneae and 479 species to the Dicotyledoneae. By far the largest families are the Asteraceae with 129 and the Poaceae with 82 species. Thirteen Red Data species were recorded. A number of fynbos elements were encountered, the most noteworthy being two families endemic to the Cape Floristic Region, the Penaeaceae and Grubbiaceae. A very high species to square kilometre ratio of 5.05 supports the area’s rich floristic composition.

U. Pond; B.B. Beesley; L.R. Brown; H. Bezuidenhout

2002-01-01

172

Reconstruction of physiological instructions from Zebra finch song  

Science.gov (United States)

We reconstruct the physiological parameters that control an avian vocal organ during birdsong production using recorded song. The procedure involves fitting the time dependent parameters of an avian vocal organ model. Computationally, the model is implemented as a dynamical system ruling the behavior of the oscillating labia that modulate the air flow during sound production, together with the equations describing the dynamics of pressure fluctuations in the vocal tract. We tested our procedure for Zebra finch song with, simultaneously recorded physiological parameters: air sac pressure and the electromyographic activity of the left and right ventral syringeal muscles. A comparison of the reconstructed instructions with measured physiological parameters during song shows a high degree of correlation. Integrating the model with reconstructed parameters leads to the synthesis of highly realistic songs.

Perl, Yonatan Sanz; Arneodo, Ezequiel M.; Amador, Ana; Goller, Franz; Mindlin, Gabriel B.

2011-11-01

173

Synthetic oligonucleotides recreate Drosophila fushi tarazu zebra-stripe expression.  

UK PubMed Central (United Kingdom)

A complex array of activator and repressor elements located within 669 bp proximal to the fushi tarazu (ftz) transcriptional start site is sufficient to generate the "zebra-stripe" expression pattern characteristic of the ftz gene. P-element-mediated transformation and ftz promoter/lacZ fusion genes were used to characterize, in detail, several of these transcriptional control elements. By reconstructing promoters with synthetic oligonucleotides containing cis-regulators of stripe expression, we show that these regulatory sites can function as independent units to direct position-specific transcription in the Drosophila embryo. In particular, we demonstrate that multiple copies of a positive regulatory site can mediate expression in both the odd- and even-numbered parasegments throughout most of the germ band and that negative regulatory sites can transform a continuous pattern of gene expression into discrete stripes. The reconstructed promoter system presented provides an effective means of studying molecular mechanisms governing spatially restricted transcription in the early embryo.

Topol J; Dearolf CR; Prakash K; Parker CS

1991-05-01

174

Transcriptional control of Drosophila fushi tarazu zebra stripe expression.  

UK PubMed Central (United Kingdom)

The Drosophila segmentation gene fushi tarazu (ftz) is expressed in a characteristic pattern of seven stripes during early embryogenesis. We have used ftz-lacZ fusion genes to determine the effects of deleting relatively small segments of the ftz promoter region necessary for this expression. We find that this regulatory region contains multiple activator and repressor elements. The deletion of one particular activator element results in a preferential loss of expression in the posterior stripes, whereas the deletion of other activator elements causes a general reduction in expression throughout the germ band. The removal of repressor elements results in a loss of repression in the odd-numbered parasegments. We also find that the ftz upstream enhancer element functions primarily in epidermal cells. Our results indicate that ftz transcription is activated in each parasegment through the 'zebra stripe' promoter region and is then inhibited selectively in the odd-numbered parasegments by repressors that bind directly to elements within this promoter region.

Dearolf CR; Topol J; Parker CS

1989-03-01

175

Improving Production of Zebra Fish Embryos in the Lab  

Directory of Open Access Journals (Sweden)

Full Text Available The utilization of fish embryos in toxicity testing of hazardous chemicals has recently been adopted in order to satisfy stricter rules and regulations related to using adult animals in toxicity testing. This paper presents optimising steps towards improving zebra fish embryo production in the laboratory. Culture conditions were maintained in the aquaria as stipulated in the OECD draft proposal for a new guideline on fish embryo tests. Furthermore, a sequence of steps were adopted and followed to improve upon previous work done in the lab in 2006. About 200 eggs were produced in one spawn trap within an hour of onset of light, an improvement over the 50 - 60 eggs produced in the previous work. This result demonstrates that with the right culture conditions and proper optimisation of procedure the required number of embryos needed for toxicity testing can be obtained.

Robert Ohene Adu; Jens Peter Thomsen

2011-01-01

176

Recent results of zebra patterns in solar radio bursts  

Science.gov (United States)

This review covers the most recent experimental results and theoretical research on zebra patterns (ZPs) in solar radio bursts. The basic attention is given to events with new peculiar elements of zebra patterns received over the last few years. All new properties are considered in light of both what was known earlier and new theoretical models. Large-scale ZPs consisting of small-scale fiber bursts could be explained by simultaneous inclusion of two mechanisms when whistler waves “highlight" the levels of double plasma resonance (DPR). A unique fine structure was observed in the event on 2006 December 13: spikes in absorption formed dark ZP stripes against the absorptive type III-like bursts. The spikes in absorption can appear in accordance with well known mechanisms of absorptive bursts. The additional injection of fast particles filled the loss-cone (breaking the loss-cone distribution), and the generation of the continuum was quenched at these moments. The maximum absorptive effect occurs at the DPR levels. The parameters of millisecond spikes are determined by small dimensions of the particle beams and local scale heights in the radio source. Thus, the DPR model helps to understand several aspects of unusual elements of ZPs. However, the simultaneous existence of several tens of the DPR levels in the corona is impossible for any realistic profile of the plasma density and magnetic field. Three new theories of ZPs are examined. The formation of eigenmodes of transparency and opacity during the propagation of radio waves through regular coronal inhomogeneities is the most natural and promising mechanism. Two other models (nonlinear periodic space - charge waves and scattering of fast protons on ion-sound harmonics) could happen in large radio bursts.

Chernov, Gennady P.

2010-09-01

177

Recent results of zebra patterns in solar radio bursts  

International Nuclear Information System (INIS)

[en] This review covers the most recent experimental results and theoretical research on zebra patterns (ZPs) in solar radio bursts. The basic attention is given to events with new peculiar elements of zebra patterns received over the last few years. All new properties are considered in light of both what was known earlier and new theoretical models. Large-scale ZPs consisting of small-scale fiber bursts could be explained by simultaneous inclusion of two mechanisms when whistler waves 'highlight' the levels of double plasma resonance (DPR). A unique fine structure was observed in the event on 2006 December 13: spikes in absorption formed dark ZP stripes against the absorptive type III-like bursts. The spikes in absorption can appear in accordance with well known mechanisms of absorptive bursts. The additional injection of fast particles filled the loss-cone (breaking the loss-cone distribution), and the generation of the continuum was quenched at these moments. The maximum absorptive effect occurs at the DPR levels. The parameters of millisecond spikes are determined by small dimensions of the particle beams and local scale heights in the radio source. Thus, the DPR model helps to understand several aspects of unusual elements of ZPs. However, the simultaneous existence of several tens of the DPR levels in the corona is impossible for any realistic profile of the plasma density and magnetic field. Three new theories of ZPs are examined. The formation of eigenmodes of transparency and opacity during the propagation of radio waves through regular coronal inhomogeneities is the most natural and promising mechanism. Two other models (nonlinear periodic space - charge waves and scattering of fast protons on ion-sound harmonics) could happen in large radio bursts. (invited reviews)

2010-09-01

178

Serine-173 of the Epstein-Barr virus ZEBRA protein is required for DNA binding and is a target for casein kinase II phosphorylation.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

An Epstein-Barr virus-encoded protein, ZEBRA, mediates the switch from latency to the viral lytic life cycle. ZEBRA's domain structure and DNA binding specificity resemble that of cellular transcriptional activators such as c-Fos/c-Jun. We show that ZEBRA, like c-Jun, is phosphorylated by casein kin...

Kolman, J L; Taylor, N; Marshak, D R; Miller, G

179

The use of chlorine dioxide for zebra mussel control - A perspective of treatment histories  

Energy Technology Data Exchange (ETDEWEB)

It is of utmost importance to provide updated performance results of various chemical treatments presently being utilized for zebra mussel control. Zebra mussels have a distinctive ability to endure environmental changes by reproducing effectively and attaching to various hard surfaces. These traits are cause for concern and have resulted in some operating difficulties for industries bordering infested waterways. Various methods are being employed by industries to deal with the problems associated with these species. One of the options is control via chemical treatment. Prior field test studies showed that chlorine dioxide was determined to be an effective molluscicidal agent for adult zebra mussel eradication. Continuous feed of chlorine dioxide at treatment levels ranging from 0.25 - 5.0 ppm above the oxidant demand provided 100% adult zebra mussel mortality which required between 2.9 - 8.8 days of treatment. Previous studies also showed that water temperature was an essential parameter in determining the time required to achieve 100% mortality of adult zebra mussels. Further field applications were undertaken at three electric utility sites located in the midwest. These facilities were concerned with the potential for zebra mussels to reduce efficiency and availability by blocking water flow or plugging equipment. Treatment applications at these facilities consisted of a continuous feed of chlorine dioxide ranging from 0.15 - 0.5 ppm above the oxidant demand. Significant mortality was achieved in monitored mussels tested at each utility in a period ranging from two to four days. This time period was directly related to a number of parameters, with the predominant one being water temperature. Data from these field applications is presented in this paper and confirms that chlorine dioxide is an effective molluscicide for adult zebra mussel control.

Smolik, N.; Rusznak, L.; Anderson, J.; Hale, L. [Ashland Chemical Coman, Drew Division, Booton, NJ (United States)

1995-06-01

180

Zebra stripes in the Atacama Desert: Fossil evidence of overland flow  

Science.gov (United States)

Some hillslopes in the hyperarid region of the Atacama Desert in northern Chile have surface clasts organized into distinct, contour-parallel bands separated by bare soil. We call the bands "zebra stripes" due to the contrast between the darkly varnished clasts and the light-colored, salt-rich soil. Gravel that comprises the zebra stripes is sorted such that the coarsest clasts are at the downslope front and fine progressively upslope. How and when the zebra stripes formed are perplexing questions, particularly in a region experiencing prolonged hyperaridity. Using GoogleEarth, satellite imagery, and field observations, we report the first quantitative and qualitative observations of zebra stripes in order to test hypotheses of the mechanisms and timing of their formation. We consider soil shrink-swell, seismic shaking, and overland flow as possible formation mechanisms, and find that overland flow is the most likely. Based on cosmogenic 10Be concentrations in surface clasts, salt deposition rates from the atmosphere, and content in the soils, we propose that the salt-rich soils began accumulating ~ 106 y ago and the zebra stripes formed 103-104 y at the latest. The zebra stripe pattern has been preserved due to the self-stabilization of the clasts within the stripes and the continued absence of life (which would disturb the surface, as seen at a wetter site to the south). We conclude that the occurrence of zebra stripes is diagnostic of a set of distinct characteristics of local and/or regional precipitation, soil, hillslope form, and bedrock type.

Owen, Justine J.; Dietrich, William E.; Nishiizumi, Kuni; Chong, Guillermo; Amundson, Ronald

2013-01-01

 
 
 
 
181

Phosphoacceptor Site S173 in the Regulatory Domain of Epstein-Barr Virus ZEBRA Protein Is Required for Lytic DNA Replication but Not for Activation of Viral Early Genes?  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The Epstein-Barr virus ZEBRA protein controls the viral lytic cycle. ZEBRA activates the transcription of viral genes required for replication. ZEBRA also binds to oriLyt and interacts with components of the viral replication machinery. The mechanism that differentiates the roles of ZEBRA in regulat...

El-Guindy, Ayman; Heston, Lee; Delecluse, Henri-Jacques; Miller, George

182

LETHALITY OF PSEUDOMONAS FLUORESCENS STRAIN CLO145A TO THE 2 ZEBRA MUSSEL SPECIES PRESENT IN NORTH AMERICA  

Energy Technology Data Exchange (ETDEWEB)

These experiments indicated that bacterial strain CL0145A of Pseudomonas fluorescens is equally lethal to the 2 zebra mussel species present in North America, Dreissena polymorpha and Dreissena bugensis. Thus, this bacterial strain should be equally effective at killing zebra mussels in power plant pipes, irrespective of which species is present.

Daniel P. Molloy

2001-10-28

183

Incidence, Distribution, and Genetic Variations of ‘Candidatus Liberibacter sp.' Associated with Zebra Chip of Potato in North America.  

Science.gov (United States)

The presence of ‘Candidatus Liberibacter solanacearum’ (CLs) and ‘Candidatus Liberibacter psyllaurous’ (CLp) were confirmed in potato plants affected with zebra chip/zebra complex (ZC) disease throughout Texas potato production areas in 2005-2008, in seed tubers produced from Wyoming in 2007, and in...

184

Modeling the Role of Zebra Mussels in the Proliferation of Blue-green Algae in Saginaw Bay, Lake Huron  

Science.gov (United States)

Under model assumptions from Saginaw Bay 1991, selective rejection of blue-green algae by zebra mussels appears to be a necessary factor in the enhancement of blue-green algae production in the presence of zebra mussels. Enhancement also appears to depend on the increased sedime...

185

Seasonal effects of the zebra mussel (Dreissena polymorpha) on sediment denitrification rates in Pool 8 of the Upper Mississippi River  

Science.gov (United States)

Zebra mussels (Dreissena polymorpha) have altered the structure of invaded ecosystems and exhibit characteristics that suggest they may influence ecosystem processes such as nitrogen (N) cycling. We measured denitrification rates seasonally on sediments underlying zebra mussel beds collected from the impounded zone of Navigation Pool 8 of the Upper Mississippi River. Denitrification assays were amended with nutrients to characterize variation in nutrient limitation of denitrification in the presence or absence of zebra mussels. Denitrification rates at zebra mussel sites were high relative to sites without zebra mussels in February 2004 (repeated measures analysis of variance (RM ANOVA), p = 0.005), potentially because of high NO3-N variability from nitrification of high NH4+ zebra mussel waste. Denitrification rates were highest in June 2003 (RM ANOVA, p 3-N concentrations during the study (linear regression, R2 = 0.72, p p ? 0.01). Examining how zebra mussels influence denitrification rates will aid in developing a more complete understanding of the impact of zebra mussels and more effective management strategies of eutrophic waters.

Bruesewitz, Denise A.; Tank, Jennifer L.; Bernot, Melody J.; Richardson, William B.; Strauss, Eric A.

2006-01-01

186

Zebra chip disease symptoms are positively associated with pathogenesis-related protein activity and phenolic compound levels in tubers  

Science.gov (United States)

Zebra chip disease, putatively caused by the bacterium 'Candidatus Liberibacter solanacearum', is an emerging problem for potato growers throughout North America. However, little is known about the physiological changes that occur in diseased plants beyond the eponymous zebra chip symptom. One physi...

187

Disruption of Epstein-Barr Virus Latency in the Absence of Phosphorylation of ZEBRA by Protein Kinase C  

Digital Repository Infrastructure Vision for European Research (DRIVER)

ZEBRA protein converts Epstein-Barr virus (EBV) infection from the latent to the lytic state. The ability of ZEBRA to activate this switch is strictly dependent on the presence of serine or threonine at residue 186 of the protein (A. Francis, T. Ragoczy, L. Gradoville, A. El-Guindy, and G. Miller, J...

El-Guindy, Ayman S.; Heston, Lee; Endo, Yoshimi; Cho, Myung-Sam; Miller, George

188

Effects of the exotic zebra mussel (Dreissena polymorpha) on metal cycling in Lake Erie  

Energy Technology Data Exchange (ETDEWEB)

This research demonstrated the impact of high densities of the zebra mussel (Dreissena polymorpha) on the cycling of copper, nickel, and zinc in a lake environment. Experiments with mussels on sedimentation traps in western Lake Erie and with mussels in flow-through tanks receiving Lake Erie water showed that zebra mussels remove metals from the water column, incorporate metals in their tissues, and deposit metals on the lake bottom. Removal of metals from the water column was estimated at 10-17%{center_dot}day{sup -1} of the amounts present. This material was largely deposited on the lake bottom; zebra mussels more than doubled the rate at which metals were being added to the lake bottom. Metal biodeposition rates were extremely high (e.g., 50 mg Zn{center_dot}m{sup -2}{center_dot}day{sup -1}) in high-turbidity areas with elevated metal levels. Two factors contributed to metal biodeposition by zebra mussels. First, their production of feces and pseudofeces increased the rate at which suspended matter was being added to the sediment (accounting for 92% of the increased metal biodeposition). Second, the material coming out of suspension had higher metal concentrations when zebra mussels were present (constituting 8% of the increased biodeposition). (author)

Klerks, P.L. [Univ. of Southwestern Louisiana, Dept. of Biology, Lafayette, Louisiana (United States)]. E-mail: klerks@usl.edu; Fraleigh, P.C.; Lawniczak, J.E. [Univ. of Toledo, Dept. of Biology, Toledo, Ohio (United States)

1997-07-15

189

Novel Proteins Identified in the Insoluble Byssal Matrix of the Freshwater Zebra Mussel.  

UK PubMed Central (United Kingdom)

The freshwater zebra mussel, Dreissena polymorpha, is an invasive, biofouling species that adheres to a variety of substrates underwater, using a proteinaceous anchor called the byssus. The byssus consists of a number of threads with adhesive plaques at the tips. It contains the unusual amino acid 3, 4-dihydroxyphenylalanine (DOPA), which is believed to play an important role in adhesion, in addition to providing structural integrity to the byssus through cross-linking. Extensive DOPA cross-linking, however, renders the zebra mussel byssus highly resistant to protein extraction, and therefore limits byssal protein identification. We report here on the identification of seven novel byssal proteins in the insoluble byssal matrix following protein extraction from induced, freshly secreted byssal threads with minimal cross-linking. These proteins were identified by LC-MS/MS analysis of tryptic digests of the matrix proteins by spectrum matching against a zebra mussel cDNA library of genes unique to the mussel foot, the organ that secretes the byssus. All seven proteins were present in both the plaque and thread. Comparisons of the protein sequences revealed common features of zebra mussel byssal proteins, and several recurring sequence motifs. Although their sequences are unique, many of the proteins display similarities to marine mussel byssal proteins, as well as to adhesive and structural proteins from other species. The large expansion of the byssal proteome reported here represents an important step towards understanding zebra mussel adhesion.

Gantayet A; Rees DJ; Sone ED

2013-09-01

190

A Physical Explanation on Solar Microwave Zebra Pattern with the Current-carrying Plasma Loop Model  

CERN Document Server

Microwave zebra pattern structure is an intriguing fine structure on the dynamic spectra of solar type IV radio burst. Up to now, there isn't a perfect physical model for the origin of the solar microwave zebra pattern. Recently, Ledenev, Yan and Fu (2006) put forward an interference mechanism to explain the features of microwave zebra patterns in solar continuum events. This model needs a structure with a multitude of discrete narrow-band sources of small size. Based on the model of current-carrying plasma loop and the theory of tearing mode instability, we proposed that the above structure does exist and may provide the main conditions for the interference mechanism. With this model, we may explain the frequency upper limit, the formation of the parallel and equidistant stripes, the superfine structure and intermediate frequency drift rate of the zebra stripes. If this explanation is valid, the zebra pattern structures can reveal some information of the motion and the inner structures of the coronal plasma ...

Tan, Baolin

2009-01-01

191

Effects of the exotic zebra mussel (Dreissena polymorpha) on metal cycling in Lake Erie  

International Nuclear Information System (INIS)

[en] This research demonstrated the impact of high densities of the zebra mussel (Dreissena polymorpha) on the cycling of copper, nickel, and zinc in a lake environment. Experiments with mussels on sedimentation traps in western Lake Erie and with mussels in flow-through tanks receiving Lake Erie water showed that zebra mussels remove metals from the water column, incorporate metals in their tissues, and deposit metals on the lake bottom. Removal of metals from the water column was estimated at 10-17%·day-1 of the amounts present. This material was largely deposited on the lake bottom; zebra mussels more than doubled the rate at which metals were being added to the lake bottom. Metal biodeposition rates were extremely high (e.g., 50 mg Zn·m-2·day-1) in high-turbidity areas with elevated metal levels. Two factors contributed to metal biodeposition by zebra mussels. First, their production of feces and pseudofeces increased the rate at which suspended matter was being added to the sediment (accounting for 92% of the increased metal biodeposition). Second, the material coming out of suspension had higher metal concentrations when zebra mussels were present (constituting 8% of the increased biodeposition). (author)

1997-01-01

192

Concerning mechanisms for the zebra pattern formation in the solar radio emission  

International Nuclear Information System (INIS)

[en] The nature of the zebra patterns in continuous type-IV solar radio bursts is discussed. The most comprehensively developed models of such patterns involve mechanisms based on the double plasma resonance and plasma wave-whistler interaction. Over the last five years, there have appeared a dozen papers concerning the refinement of the mechanism based on the double plasma resonance, because, in its initial formulation, this mechanism failed to describe many features of the zebra pattern. It is shown that the improved model of this mechanism with a power-law distribution function of hot electrons within the loss cone is inapplicable to the coronal plasma. In recent papers, the formation of the zebra pattern in the course of electromagnetic wave propagation through the solar corona was considered. In the present paper, all these models are estimated comparatively. An analysis of recent theories shows that any types of zebra patterns can form in the course of radio wave propagation in the corona, provided that there are plasma inhomogeneities of different scales on the wave path. The superfine structure of zebra stripes in the form of millisecond spikes with a strict period of ?30 ms can be attributed to the generation of continuous radio emission in the radio source itself, assuming that plasma inhomogeneities are formed by a finite-amplitude wave with the same period.

2009-01-01

193

Bioaccumulation of human waterborne protozoa by zebra mussel (Dreissena polymorpha): Interest for water biomonitoring.  

UK PubMed Central (United Kingdom)

Cryptosporidium parvum, Giardia duodenalis and Toxoplasma gondii are ubiquitous pathogens, which waterborne transmission has been largely demonstrated. Since they can be found in various watercourses, interactions with aquatic organisms are possible. Protozoan detection for watercourses biomonitoring is currently based on large water filtration. The zebra mussel, Dreissena polymorpha, is a choice biological model in ecotoxicological studies which are already in use to detect chemical contaminations in watercourses. In the present study, the zebra mussel was tested as a new tool for detecting water contamination by protozoa. In vivo exposures were conducted in laboratory experiments. Zebra mussel was exposed to various protozoan concentrations for one week. Detection of protozoa was realized by Taqman real time qPCR. Our experiments evidenced C. parvum, G. duodenalis and T. gondii oocyst bioaccumulation by mussels proportionally to ambient contamination, and significant T. gondii prevalence was observed in muscle tissue. To our knowledge, this is the first study that demonstrates T. gondii oocyst accumulation by zebra mussel. The results from this study highlight the capacity of zebra mussels to reveal ambient biological contamination, and thus to be used as a new effective tool in sanitary biomonitoring of water bodies.

Palos Ladeiro M; Aubert D; Villena I; Geffard A; Bigot A

2013-09-01

194

Trophic interference by Salmo trutta on Aplochiton zebra and Aplochiton taeniatus in southern Patagonian lakes.  

UK PubMed Central (United Kingdom)

The length and mass ratio, diet and isotopic composition of Aplochiton zebra and Aplochiton taeniatus inhabiting a Salmo trutta-invaded and a S. trutta-free lake in southern Patagonia were compared. Results indicate that S. trutta exercises important trophic interference over A. zebra and A. taeniatus, causing changes in their dietary composition by reducing the consumption of winged Diptera through changes in feeding behaviours that involve jumping out of the water. This effect is significantly higher in A. zebra than in A. taeniatus a species that has a highly specialized diet. The dietary changes of A. zebra and A. taeniatus in sympatry with S. trutta lead to an impoverishment of their isotopic nitrogen signals (?(15)N), suggesting a reduction of their trophic position. In the case of A. zebra, this translates into a significant decrease in its body condition factor. Such interference could lead to a population decline of this species and would explain the current distribution range decline and allopatry with S. trutta in fluvial systems.

Elgueta A; González J; Ruzzante DE; Walde SJ; Habit E

2013-02-01

195

Putative identification of expressed genes associated with attachment of the zebra mussel (Dreissena polymorpha).  

UK PubMed Central (United Kingdom)

Because of its aggressive growth and firm attachment to substrata, the zebra mussel (Dreissena polymorpha) has caused severe economic and ecological problems since its invasion into North America. The nature and details of attachment of this nuisance mollusc remains largely unexplored. Byssus, a special glandular apparatus located at the root of the foot of the mussel produces threads and plates through which firm attachment of the mollusc to underwater objects takes place. In an attempt to better understand the adhesion mechanism of the zebra mussel, the suppression subtractive hybridization (SSH) assay was employed to produce a cDNA library with genes unique to the foot of the mussel. Analysis of the SSH cDNA library revealed the presence of 750 new expressed sequence tags (ESTs) including 304 contigs and 446 singlets. Using BLAST search, 365 zebra mussel ESTs showed homology to other gene sequences with putative functions. The putative functions of the homologues included proteins involved in byssal thread formation in zebra and blue mussels, exocrine gland secretion, host defence, and house keeping. The generated data provide, for the first time, some useful insights into the foot structure of the zebra mussel and its underwater adhesion.

Xu W; Faisal M

2008-01-01

196

Current and modeled potential distribution of the zebra mussel (Dreissena polymorpha) in Sweden  

UK PubMed Central (United Kingdom)

In this study, we report the results from a recently performed survey of zebra mussel in Sweden and present a risk model for the potential distribution of the species. The zebra mussel was found in 11 of the 30 surveyed lakes and rivers. Most of the observations were made in the north-eastern parts of Lake Mälaren, i.e., in the basins Ekoln, Skarven, and Görväln. Hierarchical partitioning and stepwise selection of water chemistry variables in a multiple logistic model identified pH and magnesium concentrations as the best predictors for zebra mussel occurrence. We conjecture that magnesium is an important predictor due to its crucial role in mussel physiology. The logistic model was applied on 2,781 lakes and in total 109 lakes (3.9%), most of them situated in specific areas in central Sweden, in the very south and on the island of Gotland, were predicted to be potentially at risk for zebra mussel invasions. The lakes potentially at risk for zebra mussel invasions are separated by the soft-water boreal lakes that constitute the vast majority of lakes on the Fennoscandian peninsula, thus forming barriers for further dispersal.

Hallstan Simon; Grandin Ulf; Goedkoop Willem

2010-01-01

197

Increase deposition of organic matter, polychlorinated biphenyls, and cadmium by zebra mussels (Dreissena polymorpha) in western Lake Erie  

Energy Technology Data Exchange (ETDEWEB)

Biodeposition of polychlorinated biphenyls (PCBs)and cadmium by zebra mussels in the western basin of Lake Erie was investigated using sediment traps, and compared to natural rates of sedimentation. On a per unit area of organic matter, deposition rates by zebra mussels up to eight to ten times higher than natural rates of sedimentation were found. These results suggest that zebra mussels are altering contaminant movement in western Lake Erie. At the same time, it was also suggested that the net effect of biodeposition may not be as great as shown in this study since only the effects of zebra mussels on the flux of the contaminants was examined and the re-suspension factor was not considered. It was recommended that to better understand the overall effects of zebra mussels on contaminant dynamics in aquatic environments, future studies should incorporate the re-suspension factors. 27 refs., 8 tabs., 3 figs.

Dobson, E. P; Mackie, G. L. [Guelph Univ., Dept. of Zoology, ON (Canada)

1998-05-01

198

Pathology and immunohistochemistry of papillomavirus-associated cutaneous lesions in Cape mountain zebra, giraffe, sable antelope and African buffalo in South Africa.  

UK PubMed Central (United Kingdom)

Skin lesions associated with papillomaviruses have been reported in many animal species and man. Bovine papillomavirus (BVP) affects mainly the epidermis, but also the dermis in several species including bovine, the best-known example being equine sarcoid, which is associated with BVP types 1 and 2. This publication describes and illustrates the macroscopic and histological appearance of BPV-associated papillomatous, fibropapillomatous or sarcoid-like lesions in Cape mountain zebra (Equus zebra zebra) from the Gariep Dam Nature Reserve, 2 giraffes (Giraffa camelopardalis) from the Kruger National Park, and a sable antelope (Hippotragus niger) from the Kimberley area of South Africa. An African buffalo (Syncerus caffer) cow from Kruger National Park also had papillomatous lesions but molecular characterisation of lesional virus was not done. Immunohistochemical staining using polyclonal rabbit antiserum to chemically disrupted BPV-1, which cross-reacts with the L1 capsid of most known papillomaviruses, was positive in cells of the stratum granulosum of lesions in Giraffe 1, the sable and the buffalo and negative in those of the zebra and Giraffe 2. Fibropapillomatous and sarcoid-like lesions from an adult bovine were used as positive control for the immunohistochemistry and are described and the immunohistochemistry illustrated for comparison. Macroscopically, both adult female giraffe had severely thickened multifocal to coalescing nodular and occasionally ulcerated lesions of the head, neck and trunk with local poorly-circumscribed invasion into the subcutis. Necropsy performed on the 2nd giraffe revealed neither internal metastases nor serious underlying disease. Giraffe 1 had scattered, and Giraffe 2 numerous, large, anaplastic, at times indistinctly multinucleated dermal fibroblasts with bizarre nuclei within the sarcoid-like lesions, which were BPV-1 positive in Giraffe 1 and BPV-1 and -2 positive in Giraffe 2 by RT-PCR. The sable antelope presented with a solitary large lesion just proximal to the right hind hoof, which recurred after excision, and was BPV-1 positive by RT-PCR. Other wart-like growths were present elsewhere on the body. The Cape mountain zebra either succumbed from their massive lesions or were euthanased or removed from the herd because of them. The lesions were BPV-1 and/or -2 positive by RT-PCR. The buffalo lesions were wart-like papillomatous projections in the inguinal and udder region. Stratum granulosum cells that stained immunohistochemically positive in the various species appeared koilocyte-like, as described in human papillomaviral lesions.

Williams JH; van Dyk E; Nel PJ; Lane E; Van Wilpe E; Bengis RG; de Klerk-Lorist LM; van Heerden J

2011-06-01

199

Pathology and immunohistochemistry of papillomavirus-associated cutaneous lesions in Cape mountain zebra, giraffe, sable antelope and African buffalo in South Africa.  

Science.gov (United States)

Skin lesions associated with papillomaviruses have been reported in many animal species and man. Bovine papillomavirus (BVP) affects mainly the epidermis, but also the dermis in several species including bovine, the best-known example being equine sarcoid, which is associated with BVP types 1 and 2. This publication describes and illustrates the macroscopic and histological appearance of BPV-associated papillomatous, fibropapillomatous or sarcoid-like lesions in Cape mountain zebra (Equus zebra zebra) from the Gariep Dam Nature Reserve, 2 giraffes (Giraffa camelopardalis) from the Kruger National Park, and a sable antelope (Hippotragus niger) from the Kimberley area of South Africa. An African buffalo (Syncerus caffer) cow from Kruger National Park also had papillomatous lesions but molecular characterisation of lesional virus was not done. Immunohistochemical staining using polyclonal rabbit antiserum to chemically disrupted BPV-1, which cross-reacts with the L1 capsid of most known papillomaviruses, was positive in cells of the stratum granulosum of lesions in Giraffe 1, the sable and the buffalo and negative in those of the zebra and Giraffe 2. Fibropapillomatous and sarcoid-like lesions from an adult bovine were used as positive control for the immunohistochemistry and are described and the immunohistochemistry illustrated for comparison. Macroscopically, both adult female giraffe had severely thickened multifocal to coalescing nodular and occasionally ulcerated lesions of the head, neck and trunk with local poorly-circumscribed invasion into the subcutis. Necropsy performed on the 2nd giraffe revealed neither internal metastases nor serious underlying disease. Giraffe 1 had scattered, and Giraffe 2 numerous, large, anaplastic, at times indistinctly multinucleated dermal fibroblasts with bizarre nuclei within the sarcoid-like lesions, which were BPV-1 positive in Giraffe 1 and BPV-1 and -2 positive in Giraffe 2 by RT-PCR. The sable antelope presented with a solitary large lesion just proximal to the right hind hoof, which recurred after excision, and was BPV-1 positive by RT-PCR. Other wart-like growths were present elsewhere on the body. The Cape mountain zebra either succumbed from their massive lesions or were euthanased or removed from the herd because of them. The lesions were BPV-1 and/or -2 positive by RT-PCR. The buffalo lesions were wart-like papillomatous projections in the inguinal and udder region. Stratum granulosum cells that stained immunohistochemically positive in the various species appeared koilocyte-like, as described in human papillomaviral lesions. PMID:22135923

Williams, J H; van Dyk, E; Nel, P J; Lane, E; Van Wilpe, E; Bengis, R G; de Klerk-Lorist, L M; van Heerden, J

2011-06-01

200

Pathology and immunohistochemistry of papillomavirus-associated cutaneous lesions in Cape mountain zebra, giraffe, sable antelope and African buffalo in South Africa  

Directory of Open Access Journals (Sweden)

Full Text Available Skin lesions associated with papillomaviruses have been reported in many animal species and man. Bovine papillomavirus (BVP) affects mainly the epidermis, but also the dermis in several species including bovine, the best-known example being equine sarcoid, which is associated with BVP types 1 and 2. This publication describes and illustrates the macroscopic and histological appearance of BPV-associated papillomatous, fibropapillomatous or sarcoid-like lesions in Cape mountain zebra (Equus zebra zebra) from the Gariep Dam Nature Reserve, 2 giraffes (Giraffa camelopardalis) from the Kruger National Park, and a sable antelope (Hippotragus niger) from the Kimberley area of South Africa. An African buffalo (Syncerus caffer) cow from Kruger National Park also had papillomatous lesions but molecular characterisation of lesional virus was not done. Immunohistochemical staining using polyclonal rabbit antiserum to chemically disrupted BPV-1, which cross-reacts with the L1 capsid of most known papillomaviruses, was positive in cells of the stratum granulosum of lesions in Giraffe 1, the sable and the buffalo and negative in those of the zebra and Giraffe 2. Fibropapillomatous and sarcoid-like lesions from an adult bovine were used as positive control for the immunohistochemistry and are described and the immunohistochemistry illustrated for comparison. Macroscopically, both adult female giraffe had severely thickened multifocal to coalescing nodular and occasionally ulcerated lesions of the head, neck and trunk with local poorly-circumscribed invasion into the subcutis. Necropsy performed on the 2nd giraffe revealed neither internal metastases nor serious underlying disease. Giraffe 1 had scattered, and Giraffe 2 numerous, large, anaplastic, at times indistinctly multinucleated dermal fibroblasts with bizarre nuclei within the sarcoid-like lesions, which were BPV-1 positive in Giraffe 1 and BPV-1 and -2 positive in Giraffe 2 by RT-PCR. The sable antelope presented with a solitary large lesion just proximal to the right hind hoof, which recurred after excision, and was BPV-1 positive by RT-PCR. Other wart-like growths were present elsewhere on the body. The Cape mountain zebra either succumbed from their massive lesions or were euthanased or removed from the herd because of them. The lesions wereBPV-1 and/or -2 positive byRT-PCR. The buffalo lesions were wart-like papillomatous projections in the inguinal and udder region. Stratum granulosum cells that stained immunohistochemically positive in the various species appeared koilocyte-like, as described in human papillomaviral lesions.

J. H. Williams; E. van Dyk; P. J. Nel; E. Lane; E. Van Wilpe; R. G. Bengis; L-M. de Klerk-Lorist; J. van Heerden

2012-01-01

 
 
 
 
201

Pathology and immunohistochemistry of papillomavirus-associated cutaneous lesions in Cape mountain zebra, giraffe, sable antelope and African buffalo in South Africa  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english Skin lesions associated with papillomaviruses have been reported in many animal species and man. Bovine papillomavirus (BVP) affects mainly the epidermis, but also the dermis in several species including bovine, the best-known example being equine sarcoid, which is associated with BVP types 1 and 2. This publication describes and illustrates the macroscopic and histological appearance of BPV-associated papillomatous, fibropapillomatous or sarcoid-like lesions in Cape moun (more) tain zebra (Equus zebra zebra) from the Gariep Dam Nature Reserve, 2 giraffes (Giraffa camelopardalis) from the Kruger National Park, and a sable antelope (Hippotragus niger) from the Kimberley area of South Africa. An African buffalo (Syncerus caffer) cow from Kruger National Park also had papillomatous lesions but molecular characterisation of lesional virus was not done. Immunohistochemical staining using polyclonal rabbit antiserum to chemically disrupted BPV-1, which cross-reacts with the L1 capsid of most known papillomaviruses, was positive in cells of the stratum granulosum of lesions in Giraffe 1, the sable and the buffalo and negative in those of the zebra and Giraffe 2. Fibropapillomatous and sarcoid-like lesions from an adult bovine were used as positive control for the immunohistochemistry and are described and the immunohistochemistry illustrated for comparison. Macroscopically, both adult female giraffe had severely thickened multifocal to coalescing nodular and occasionally ulcerated lesions of the head, neck and trunk with local poorly-circumscribed invasion into the subcutis. Necropsy performed on the 2nd giraffe revealed neither internal metastases nor serious underlying disease. Giraffe 1 had scattered, and Giraffe 2 numerous, large, anaplastic, at times indistinctly multinucleated dermal fibroblasts with bizarre nuclei within the sarcoid-like lesions, which were BPV-1 positive in Giraffe 1 and BPV-1 and -2 positive in Giraffe 2 by RT-PCR. The sable antelope presented with a solitary large lesion just proximal to the right hind hoof, which recurred after excision, and was BPV-1 positive by RT-PCR. Other wart-like growths were present elsewhere on the body. The Cape mountain zebra either succumbed from their massive lesions or were euthanased or removed from the herd because of them. The lesions were BPV-1 and/or -2 positive by RT-PCR. The buffalo lesions were wart-like papillomatous projections in the inguinal and udder region. Stratum granulosum cells that stained immunohistochemically positive in the various species appeared koilocyte-like, as described in human papillomaviral lesions.

Williams, J H; Dyk, E van; Nel, P J; Lane, E; Wilpe, E Van; Bengis, R G; Klerk-Lorist, L-M de; van Heerden, J

2011-01-01

202

Lessons learned in over 100 zebra mussel control applications at industrial facilities  

Energy Technology Data Exchange (ETDEWEB)

Since their introduction into US waterways, Zebra Mussels (Dreissena polymorphae) have spread rapidly throughout the Great Lakes and Mississippi regions. These mussels have continued to colonize the intake pipes of industrial water supplies and water distribution systems throughout the affected areas. Their colonization has compromised plant safety and production efficiency, and steadily increased costs to water users. The design of each industrial plant water distribution system is unique. A comprehensive zebra mussel control strategy using the best available options must be considered in each specific situation. This paper discusses the successful use of one strategy (a quaternary ammonia-based molluscicide) in the battle against zebra mussels. The commercial life cycle of an industrial molluscicide began with initial toxicity screening in the laboratory. The evaluation continued at plant sites through field trials and applications. Lessons learned from these experiences helped direct the efforts toward the development of a second generation program.

McGough, C.M.; Gilland, P.H.; Muia, R.A. [Calgon Corp., Pittsburgh, PA (United States)

1998-12-31

203

Preliminary studies to determine the effects of pressure on zebra mussel mortality  

Energy Technology Data Exchange (ETDEWEB)

A study was carried out to determine the effects of positive and negative pressure on the survival of zebra mussels, as part of a research program aimed at preventing the attachment of mussels to the inside of water intake facilities and piping networks. The study was initiated after it was observed that few mussels were observed in the pressurized station fire fighting systems. The effects of vacuum, low pressure and high pressure on the mortality of juvenile zebra mussels were explored. Both instantaneous and long duration pressures were administered. Both vacuum and low pressure applications showed no promise with respect to controlling or destroying zebra mussels in the short term. Even though 100% mortality was found with high pressure and long exposure periods, this technique is not considered practical under normal field conditions. 13 figs., 11 tabs.

Koopmans, R.

1992-03-24

204

Transcriptional response of stress genes to metal exposure in zebra mussel larvae and adults.  

UK PubMed Central (United Kingdom)

Development of stress markers for the invader freshwater zebra mussel (Dreissena polymorpha) is of great interest for both conservation and biomonitoring purposes. Gene expression profiles of several putative or already established gene expression stress markers (Metallothionein, Superoxide dismutase, Catalase, Glutathione S transferase, Glutathione peroxidase, Cytochrome c oxidase, the multixenobiotic resistance P-gp1, and heat shock proteins HSP70 and HSP90) were analyzed by quantitative Real-Time PCR in adults and pediveliger larvae after exposure to metals (Hg, Cu, Cd). A defined pattern of coordinated responses to metal exposure and, presumably, to oxidative stress was observed in gills and digestive gland from adults. A similar, albeit partial response was observed in larvae, indicating an early development of stress-related gene responses in zebra mussel. The tools developed in this study may be useful both for future control strategies and for the use of zebra mussel as sentinel species in water courses with stable populations.

Navarro A; Faria M; Barata C; Piña B

2011-01-01

205

Scope of problem assessed at IVO. The zebra mussel`s campaign of world conquest  

Energy Technology Data Exchange (ETDEWEB)

The migrating shell - or `zebra mussel` as it is called on account of its black and white stripes - was originally a fresh-water mussel, but has since also adapted to brackish waters. As a result of human activity the species has spread quickly and widely from its native habitat. Operators of power plants and water treatment plants in particular have not been very happy about this. During its larval stage the zebra mussel can enter the cooling water systems; fasten itself to the pipes and - in the worst case - clog the system. The Environmental Protection Division of IVO has been assessing the spread of the zebra mussel and the resulting problems with the aid of reference literature and the assistance of Finnish researchers

Silvonen, J.; Oesch, P. [ed.

1998-07-01

206

Low frequency sound as a control measure for zebra mussel fouling  

Energy Technology Data Exchange (ETDEWEB)

The study of the effect of acoustic energy on zebra mussels first began in the Soviet Union over 30 years ago, where researchers indicated the feasibility of reducing Dreissena fouling, in particular on cooling systems. However, these studies were discontinued due to the successful use of chlorination and the relatively low level of technology at that time in the Soviet Union. Interest in the use of acoustic energy as a control measure has been revived, and the three major approaches are: (1) cavitation, (2) sound treatment, and (3) sound treatment. The objective of the present paper is to determine the feasibility and effectivensss of low frequency sound techniques to fight zebra mussel fouling. A number of experiments were performed, and the results are presented and discussed. It is concluded that low frequency sound can be an effective means of control of zebra mussel fouling.

Donskoy, D.M. [Stevens Institute of Technology, Hoboken, NJ (United States); Ludyanskiy, M.L. [LONZA, Inc., Annandale, NJ (United States)

1995-06-01

207

Metabolism of chlorobenzene and hexachlorobenzene by the zebra fish, Brachydanio rerio  

Energy Technology Data Exchange (ETDEWEB)

It is now becoming evident that in many cases metabolites have a greater toxic potential than the parent xenobiotic exposed. For this reason, the knowledge of biotransformation pathways of xenobiotics plays a substantial role in environmental monitoring programs. The zebra fish (Brachydanio rerio, Hamilton-Buchanan) has received increased attention as a model species for freshwater fish in environmental surveillance programs to evaluate potential health and impacts of anthropogenic chemicals. The metabolism of phenol and various substituted phenols in zebra fish has recently been studied. The purpose of the present study was to examine the metabolism of chlorobenzene and hexachlorobenzene (HCB), by the zebra fish following in vivo exposure of sublethal concentrations in the water.

Kasokat, T.; Nagel, R.; Urich, K.

1989-02-01

208

Structural activity relationship studies of zebra mussel antifouling and antimicrobial agents from verongid sponges.  

UK PubMed Central (United Kingdom)

Several dibromotyramine derivatives including moloka'iamine were selected as potential zebra mussel (Dreissena polymorpha) antifoulants due to the noteworthy absence of fouling observed on sponges of the order Verongida. Sponges of the order Verongida consistently produce these types of bromotyrosine-derived secondary metabolites. Previously reported antifouling data for the barnacle Balanus amphitrite(EC50 = 12.2 microM) support the results reported here that the compound moloka'iamine may be a potential zebra mussel antifoulant compound (EC50 = 10.4 microM). The absence of phytotoxic activity of the compound moloka'iamine toward Lemna pausicostata and, most importantly, the compound's significant selectivity against macrofouling organisms such as zebra mussels suggest the potential utility of this compound as a naturally derived antifoulant lead.

Diers JA; Pennaka HK; Peng J; Bowling JJ; Duke SO; Hamann MT

2004-12-01

209

Cannabinoids inhibit zebra mussel (Dreissena polymorpha) byssal attachment: a potentially green antifouling technology.  

UK PubMed Central (United Kingdom)

Macrofouling by zebra mussels (Dreissena polymorpha) has serious environmental, economic and legal consequences for freshwater shipping and raw water facilities. Current antifouling technologies, such as organometallics or aggressive oxidisers, have negative environmental impacts limiting their application. As part of an effort to discover antifoulants with a reduced environmental footprint, the endocannabinoid, anandamide and nine other compounds sharing structural or functional features were tested for their ability to inhibit zebra mussel byssal attachment. A byssal attachment bioassay identified six efficacious compounds; four compounds also had no negative impact on mussels at concentrations maximally inhibiting byssal attachment and three of them had no significant cumulative toxicity towards a non-target organism, Daphnia magna. This discovery demonstrates that both naturally occurring and synthetic cannabinoids can serve as non-toxic efficacious zebra mussel antifoulants. Applications with this technology may lead to a new genre of cleaner antifoulants, because the strategy is to prevent attachment rather than to poison mussels.

Angarano MB; McMahon RF; Schetz JA

2009-01-01

210

ZebraZoom: an automated program for high-throughput behavioral analysis and categorization  

Science.gov (United States)

The zebrafish larva stands out as an emergent model organism for translational studies involving gene or drug screening thanks to its size, genetics, and permeability. At the larval stage, locomotion occurs in short episodes punctuated by periods of rest. Although phenotyping behavior is a key component of large-scale screens, it has not yet been automated in this model system. We developed ZebraZoom, a program to automatically track larvae and identify maneuvers for many animals performing discrete movements. Our program detects each episodic movement and extracts large-scale statistics on motor patterns to produce a quantification of the locomotor repertoire. We used ZebraZoom to identify motor defects induced by a glycinergic receptor antagonist. The analysis of the blind mutant atoh7 revealed small locomotor defects associated with the mutation. Using multiclass supervised machine learning, ZebraZoom categorized all episodes of movement for each larva into one of three possible maneuvers: slow forward swim, routine turn, and escape. ZebraZoom reached 91% accuracy for categorization of stereotypical maneuvers that four independent experimenters unanimously identified. For all maneuvers in the data set, ZebraZoom agreed with four experimenters in 73.2–82.5% of cases. We modeled the series of maneuvers performed by larvae as Markov chains and observed that larvae often repeated the same maneuvers within a group. When analyzing subsequent maneuvers performed by different larvae, we found that larva–larva interactions occurred as series of escapes. Overall, ZebraZoom reached the level of precision found in manual analysis but accomplished tasks in a high-throughput format necessary for large screens.

Mirat, Olivier; Sternberg, Jenna R.; Severi, Kristen E.; Wyart, Claire

2013-01-01

211

ZebraZoom: an automated program for high-throughput behavioral analysis and categorization.  

UK PubMed Central (United Kingdom)

The zebrafish larva stands out as an emergent model organism for translational studies involving gene or drug screening thanks to its size, genetics, and permeability. At the larval stage, locomotion occurs in short episodes punctuated by periods of rest. Although phenotyping behavior is a key component of large-scale screens, it has not yet been automated in this model system. We developed ZebraZoom, a program to automatically track larvae and identify maneuvers for many animals performing discrete movements. Our program detects each episodic movement and extracts large-scale statistics on motor patterns to produce a quantification of the locomotor repertoire. We used ZebraZoom to identify motor defects induced by a glycinergic receptor antagonist. The analysis of the blind mutant atoh7 revealed small locomotor defects associated with the mutation. Using multiclass supervised machine learning, ZebraZoom categorized all episodes of movement for each larva into one of three possible maneuvers: slow forward swim, routine turn, and escape. ZebraZoom reached 91% accuracy for categorization of stereotypical maneuvers that four independent experimenters unanimously identified. For all maneuvers in the data set, ZebraZoom agreed with four experimenters in 73.2-82.5% of cases. We modeled the series of maneuvers performed by larvae as Markov chains and observed that larvae often repeated the same maneuvers within a group. When analyzing subsequent maneuvers performed by different larvae, we found that larva-larva interactions occurred as series of escapes. Overall, ZebraZoom reached the level of precision found in manual analysis but accomplished tasks in a high-throughput format necessary for large screens.

Mirat O; Sternberg JR; Severi KE; Wyart C

2013-01-01

212

Technical maturity. Zebra battery for electric vehicles of the A class; Der Kinderstube entwachsen. Zebra-Batterie fuer Elektroantriebe: In der A-Klasse liegt Zebra zwischen den Achsen  

Energy Technology Data Exchange (ETDEWEB)

In its fourth generation, the Zebra battery (Na/NiCl{sub 2} battery) has reached the same level of technical maturity as the lead battery but with more than twice the energy density. The A class of Daimler-Benz is the first vehicle concept that was specially designed for integrating the electric drive right from the very beginning. (orig.) [Deutsch] In ihrer vierten Generation hat die Zebra-Batterie (Na/NiCl{sub 2}-Batterie) einen Reifegrad erreicht, der sich durchaus mit der Bleibatterie vergleichen lassen kann - bei mehr als doppelter Energiedichte. Und mit der A-Klasse hat Daimler-Benz erstmals ein Fahrzeugkonzept auf die Beine gestellt, das den Elektroantrieb von Anfang an integriert. (orig.)

Anon.

1998-05-01

213

UV [ultraviolet] shows promise in controlling zebra mussel scourge  

Energy Technology Data Exchange (ETDEWEB)

Zebra mussels were introduced into the Great Lakes Basin in 1985-86 and infestations have since dispersed throughout the lower lakes, the St Lawrence River, and other rivers in the central USA. Many industries and municipalities that draw water from those sources are affected by clogging of pipes by mussels and have implemented monitoring programs to determine the extent of infestation and the effectiveness of mussel control methods. Industrial and municipal water users continue to rely heavily on chlorination to control mussels, but pressure is mounting for elimination or minimization of chlorine in water systems and alternatives are being sought. These include oxidants such as ozone, molluscicides, special coatings, centrifugal separators, and electric fields. Ontario Hydro and Hydro-Quebec are conducting extensive full-scale research projects on cathodic protection, elevated levels of which have been shown to significantly decrease mussel infestation of steel surfaces. Good mussel control has been achieved using heat at a power station in New York. Research on ultraviolet light started in 1992 and both medium- and low-pressure ultraviolet lamps have proven to provide good control of mussels. It is presently felt that ultraviolet control could be applied in many low-flow situations. 1 fig.

Lewis, D

1994-03-01

214

Zebra mussels mitigation at Ontario Hydro's hydroelectric generating facilities  

International Nuclear Information System (INIS)

[en] The Great Lakes and their connecting channels have recently been invaded by a tiny freshwater mollusc that has already cost Ontario Hydro millions of dollars. Dreissena polymorpha, commonly known as the zebra mussel, entered the great lakes in ballast water carried by a ship from Europe in 1985. These mussels threaten to reduce or totally block the flow of water in auxiliary systems of any generating station, water treatment plant or municipal water facility that uses raw lake water and to cause accelerated corrosion of the metallic substrate to which they attach themselves. To satisfy the immediate need for control, chlorination was identified as the most effective interim measure to prevent the biofouling of the raw water systems. Detection and monitoring of mussels and the installation, operation, environmental constraints, benefits and deficiencies of the chemical treatment system are presented. Long term objectives for control of the mussels are to develop alternatives to chlorination (ozone, hydrogen peroxide, protective coatings, thermal shock, mechanical filtration, etc.) for application at existing facilities and for incorporation into the design of new facilities and rehabilitation programs. 3 refs., 5 figs

1992-01-01

215

Reversible and irreversible heat effects in ZEBRA cells  

Energy Technology Data Exchange (ETDEWEB)

When a sodium-nickel chloride cell is discharged reversibly, heat is liberated. The amount of heat involved has been found from measured values of the open circuit voltage of the cell over a range of temperatures. The thermal capacity of a 40 A h cell has also been measured, at various states of discharge, and is found to be a linear function of the temperature and of the degree of discharge. The information has been combined to find the temperature changes which occur when a fully charged cell undergoes a reversible discharge-charge cycle. Complete discharge of the cell involves a temperature rise of some 30-35 K, depending on the starting temperature; the effect is reversed on charge. The techniques employed in these calculations could be applied to other cells in which all reactants and products of the cell reaction are pure phases, such as the sodium-sulphur cell or ZEBRA cells involving transition metals other than nickel. (Author)

Cleaver, B.; Cleaver, D.J.; Littlewood, L. [Southampton Univ. (United Kingdom). Dept. of Chemistry; Demott, D.S. [Beta Research and Development, Derby (United Kingdom)

1995-12-01

216

Prevention and control of zebra mussels: proactive and reactive strategies  

International Nuclear Information System (INIS)

[en] Most plant people would agree that having zebra mussels in any raw water system is not desirable. System blockage, loss of heat transfer and other associated safety hazards are not pleasant to deal with. Therefore most industries strive to minimise the effect of infestation. Opinions differ as to how to do this most efficiently and economically. Some facilities are committed to preventing the settlement of veligers in their piping systems and on some of the external structures they consider critical. This is the proactive approach. Others allow settlement and only treat the system or surface after fouling has occurred. This is the reactive approach. Which is the best and most economical treatment will depend on the individual facility and sometimes on the individual system. The paper examines the different proactive and reactive strategies available to-date and how they are being used. It will also discuss some of the criteria for choosing a proactive vs. reactive approach and why the decision has to be made individually by each facility. (author)

1998-01-01

217

Development of temporal structure in zebra finch song.  

UK PubMed Central (United Kingdom)

Zebra finch song has provided an excellent case study in the neural basis of sequence learning, with a high degree of temporal precision and tight links with precisely timed bursting in forebrain neurons. To examine the development of song timing, we measured the following four aspects of song temporal structure at four age ranges between 65 and 375 days posthatch: the mean durations of song syllables and the silent gaps between them, timing variability linked to song tempo, timing variability expressed independently across syllables and gaps, and transition probabilities between consecutive syllable pairs. We found substantial increases in song tempo between 65 and 85 days posthatch, due almost entirely to a shortening of gaps. We also found a decrease in tempo variability, also specific to gaps. Both the magnitude of the increase in tempo and the decrease in tempo variability were correlated on gap-by-gap basis with increases in the reliability of corresponding syllable transitions. Syllables had no systematic increase in tempo or decrease in tempo variability. In contrast to tempo parameters, both syllables and gaps showed an early sharp reduction in independent variability followed by continued reductions over the first year. The data suggest that links between syllable-based representations are strengthened during the later parts of the traditional period of song learning and that song rhythm continues to become more regular throughout the first year of life. Similar learning patterns have been identified in human sequence learning, suggesting a potentially rich area of comparative research.

Glaze CM; Troyer TW

2013-02-01

218

Synthetic oligonucleotides recreate Drosophila fushi tarazu zebra-stripe expression.  

Science.gov (United States)

A complex array of activator and repressor elements located within 669 bp proximal to the fushi tarazu (ftz) transcriptional start site is sufficient to generate the "zebra-stripe" expression pattern characteristic of the ftz gene. P-element-mediated transformation and ftz promoter/lacZ fusion genes were used to characterize, in detail, several of these transcriptional control elements. By reconstructing promoters with synthetic oligonucleotides containing cis-regulators of stripe expression, we show that these regulatory sites can function as independent units to direct position-specific transcription in the Drosophila embryo. In particular, we demonstrate that multiple copies of a positive regulatory site can mediate expression in both the odd- and even-numbered parasegments throughout most of the germ band and that negative regulatory sites can transform a continuous pattern of gene expression into discrete stripes. The reconstructed promoter system presented provides an effective means of studying molecular mechanisms governing spatially restricted transcription in the early embryo. PMID:1851122

Topol, J; Dearolf, C R; Prakash, K; Parker, C S

1991-05-01

219

Transcriptional control of Drosophila fushi tarazu zebra stripe expression.  

Science.gov (United States)

The Drosophila segmentation gene fushi tarazu (ftz) is expressed in a characteristic pattern of seven stripes during early embryogenesis. We have used ftz-lacZ fusion genes to determine the effects of deleting relatively small segments of the ftz promoter region necessary for this expression. We find that this regulatory region contains multiple activator and repressor elements. The deletion of one particular activator element results in a preferential loss of expression in the posterior stripes, whereas the deletion of other activator elements causes a general reduction in expression throughout the germ band. The removal of repressor elements results in a loss of repression in the odd-numbered parasegments. We also find that the ftz upstream enhancer element functions primarily in epidermal cells. Our results indicate that ftz transcription is activated in each parasegment through the 'zebra stripe' promoter region and is then inhibited selectively in the odd-numbered parasegments by repressors that bind directly to elements within this promoter region. PMID:2498165

Dearolf, C R; Topol, J; Parker, C S

1989-03-01

220

The quagga and science: what does the future hold for this extinct zebra?  

UK PubMed Central (United Kingdom)

Quaggas, partially striped zebras from South Africa, have had major impacts on science. In the 19th century, the results of mating between a quagga stallion and a horse mare influenced thinking about mechanisms of inheritance for more than 70 years. In the 20th century, tissue from a quagga yielded the first DNA of an extinct organism to be cloned and sequenced. Selective breeding of plains zebras in South Africa has produced animals whose coat coloration resembles that of some quaggas. This raises the intriguing possibility that quaggas may once again be the focus of scientific investigations.

Heywood P

2013-01-01

 
 
 
 
221

Formation of zebra pattern in low-frequency Jovian radio emission  

CERN Multimedia

We investigate the formation of zebra-like fine spectral structures (consisting of several parallel bands in the dynamic spectrum) in the Jovian broadband kilometric radiation; such radio bursts were observed by Cassini in 2000/2001. We assume that the emission is generated due to a plasma mechanism in the Io plasma torus. We have shown that the double plasma resonance effect (that was proposed earlier as a formation mechanism of the solar zebra patterns) is able to produce the observed spectral structures. The observed frequency drifts are caused, most likely, by the dynamics of the electron acceleration site. The required conditions in the emission source are discussed.

Kuznetsov, A A

2012-01-01

222

Measurement and analysis of reaction rates in simulated PFR demountable subassembly heat-pins in ZEBRA  

International Nuclear Information System (INIS)

[en] Measurements completed on the Zebra reactor to assess the reliability of current diffusion-theory predictions of the power generated in DMSA heater pins in PFR, are described. A range of heater pin configurations was simulated, and reaction rates of fission in Pu 239, U 238 and U 235 and capture in U 238 were measured. These were also calculated using standard Zebra methods. The calculated-to-experimental ratios were in the range 1.03 to 1.05, giving confidence in the methods of prediction used for PFR. (U.K.)

1985-01-01

223

Formation of zebra pattern in low-frequency Jovian radio emission  

Science.gov (United States)

We investigate the formation of zebra-like fine spectral structures (consisting of several parallel bands in the dynamic spectrum) in the Jovian broadband kilometric radiation; such radio bursts were observed by Cassini in 2000/2001. We assume that the emission is generated due to a plasma mechanism in the Io plasma torus. We have shown that the double plasma resonance effect (that was proposed earlier as a formation mechanism of the solar zebra patterns) is able to produce the observed spectral structures. The observed frequency drifts are caused, most likely, by the dynamics of the electron acceleration site. The required conditions in the emission source are discussed.

Kuznetsov, A. A.; Vlasov, V. G.

2013-01-01

224

The Zebra Battery: a South African contender for electric vehicle application Die Zebra-battery - ’n Suid-Afrikaanse aanspraakmaker in die elektriesevoertuigbedryf  

Directory of Open Access Journals (Sweden)

Full Text Available The Zebra battery is one of the most promising power sources for electric vehicles which might be on sale before the year 2000. It is a South African development which started at the CSIR and is at present jointly managed by the Anglo American Corpora­tion of S.A. and the German company A.E.G. The chemical reaction converts common salt and nickel to nickel chloride and sodium during the charging phase.Die Zebra-battery is ’n sterk aanspraakmaker daarop om voor die einde van die eeu wêreldwyd die energiebron van elektriese voertuie te word. Dit is 'n Suid-Afrikaanse ontwikkeling wat by die Wetenskaplike en Nywerheidnavorsingsraad (WNNR) begin het en tans deur die Anglo American Korporasie van S.A. en die Duitse maatskappy, A.E.G., bestuur word. Die selreaksie vind plaas tussen gewone tafelsout en nikkelmetaal tydens die laaiproses om natriummetaal en nikkelchloried te vorm.

J. Coertzer; M. J. Nolte

1996-01-01

225

Development of a molecular diagnostic system to discriminate Dreissena polymorpha (zebra mussel) and Dreissena bugensis (quagga mussel).  

UK PubMed Central (United Kingdom)

A 3-primer PCR system was developed to discriminate invasive zebra (Dreissena polymorpha) and quagga (Dreissena bugensis) mussel. The system is based on: 1) universal primers that amplifies a region of the nuclear 28s rDNA gene from both species and 2) a species-specific primer complementary to either zebra or quagga mussel. The species-specific primers bind to sequences between the binding sites for the universal primers resulting in the amplification of two products from the target species and one product from the nontarget species. Therefore, nontarget products are positive amplification controls. The 3-primer system accurately discriminated zebra and quagga mussels from seven geographically distinct populations.

Hoy MS; Kelly K; Rodriguez RJ

2010-01-01

226

Maternal effects in quail and zebra finches: Behavior and hormones.  

Science.gov (United States)

Maternal effects are influences of parents on offspring phenotype occurring through pathways other than inherited DNA. In birds, two important routes for such transmission are parental behavior and non-DNA egg constituents such as yolk hormones. Offspring traits subject to parental effects include behavior and endocrine function. Research from the Adkins-Regan lab has used three avian species to investigate maternal effects related to hormones and behavior. Experiments with chickens and Japanese quail have shown that maternal sex steroids can influence sex determination to produce biased offspring sex ratios. Because all birds have a ZZ/ZW chromosomal sex determining system in which the female parent determines the sex of the offspring, these results raise the possibility that maternal steroids can influence the outcome of sex chromosome meiosis. Learning has been shown to influence egg investment by female quail in ways that are likely to alter offspring phenotype. In quail, embryonic and exogenous sex steroids have well established and long-lasting effects on sexual differentiation of behavior during a critical period in ovo, but elevated yolk testosterone has long-term effects on behavior that do not seem to be occurring through an alteration in sexual differentiation. In biparental zebra finches, removal of mothers alters not only later behavior, but also the adult response of the hypothalamic-pituitary-adrenal (HPA) axis to an environmental stressor, as indicated by plasma corticosterone. Birds raised only by fathers have lower levels of mRNA for both glucocorticoid receptors in several brain regions as adults. These studies add to the evidence that one generation influences the behavioral or endocrine phenotype of the next through routes other than transmission of DNA. Additional research will be required to understand the adaptive significance of these effects. PMID:23499787

Adkins-Regan, Elizabeth; Banerjee, Sunayana B; Correa, Stephanie M; Schweitzer, Cécile

2013-03-15

227

Some aspects of fast reactor operation studied in Zebra  

International Nuclear Information System (INIS)

[en] The paper describes four aspects of the fast reactor operating cycle that have been experimentally investigated in Zebra. (i) Curium production: sensitive radiochemical techniques for measuring the capture rates in 241Am and 243Am leading to 242Cm and 244Cm have been applied to samples irradiated in spectra characteristic of PFR and of a commercial-size reactor. The derived cross-sections are compared with those predicted using recent evaluations. (ii) Component activation: the ?-activities induced in a range of elements of potential significance to contamination of the primary circuit in core and axial-breeder locations have been determined by standardized liquid-source counting techniques. Samples of fuel-clad and subassembly wrapper alloys have also been examined. Results are compared with predictions using currently recommmended cross-sections. (iii) Decay heat: the energy release by ?-particles from fission products of 235U and 239Pu following a 105 -second irradiation has been measured over a cooling period of one year using a catcher-foil technique and a plastic scintillation detector. Comparisons with summation-code predictions are presented. (iv) Plutonium build-up: the formation of plutonium in a radial breeder has been simulated by replacing UO2 plates by PuO2/UO2 to give an average level of 2% Pu/U. The influence of this enrichment on the reaction rates of 235U, 238U and 239Pu was measured by foil activation methods. Comparisons with diffusion and transport-theory calculations are made. (author)

1979-09-28

228

STRUCTURAL ACTIVITY RELATIONSHIP STUDIES OF ZEBRA MUSSEL ANTIFOULING AND ANTIMICROBIAL AGENTS FROM VERONGID SPONGES  

Science.gov (United States)

Several dibromotyramine derivatives including moloka'iamine were selected as potential zebra mussel (Dreissena polymorpha) antifoulants due to the noteworthy absense of fouling observed on sponges of the Order Verongida. Sponges of the Order Verongida consistently produce these types of bromotyrosi...

229

Zebra Mussel Antifouling Activity of the Marine Natural Products Aaptamine and Analogs  

Science.gov (United States)

Several aaptamine derivatives were selected as potential zebra mussel (Dreissena polymorpha) antifoulants due to the noteworthy absence of fouling observed on Aaptos sponges. Sponges of the Genus Aaptos collected in Mando, Indonesia, consistently produce aaptamine-type alkaloids. To date, aaptamin...

230

Transcriptional response of stress genes to metal exposure in zebra mussel larvae and adults  

Energy Technology Data Exchange (ETDEWEB)

Development of stress markers for the invader freshwater zebra mussel (Dreissena polymorpha) is of great interest for both conservation and biomonitoring purposes. Gene expression profiles of several putative or already established gene expression stress markers (Metallothionein, Superoxide dismutase, Catalase, Glutathione S transferase, Glutathione peroxidase, Cytochrome c oxidase, the multixenobiotic resistance P-gp1, and heat shock proteins HSP70 and HSP90) were analyzed by quantitative Real-Time PCR in adults and pediveliger larvae after exposure to metals (Hg, Cu, Cd). A defined pattern of coordinated responses to metal exposure and, presumably, to oxidative stress was observed in gills and digestive gland from adults. A similar, albeit partial response was observed in larvae, indicating an early development of stress-related gene responses in zebra mussel. The tools developed in this study may be useful both for future control strategies and for the use of zebra mussel as sentinel species in water courses with stable populations. - Coordinated expression of stress genes in zebra mussel.

Navarro, Anna; Faria, Melissa; Barata, Carlos [Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona 18, 08034 Barcelona (Spain); Pina, Benjamin, E-mail: bpcbmc@cid.csic.e [Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona 18, 08034 Barcelona (Spain)

2011-01-15

231

Bioaccumulation of PAHs in the zebra mussel, Dreissena polymorpha, at Times Beach, New York  

Energy Technology Data Exchange (ETDEWEB)

While zebra mussels have not been reported in confined disposal facilities (CDFs), recent reports of zebra mussels in soft sediments indicate a possible concern for dredging and the disposal of dredged material. In response to this concern, an insitu biomonitoring study utilizing the zebra mussel was performed at the Times Beach CDF, in Buffalo, NY. Mussels were placed at the facility for 30 days at sites of known PAH concentrations. The placement occurred at areas of comparably high, intermediate and low total PAH sediment concentrations. At each site the mussels were placed both in the water column and at the sediment surface. Mussels were collected on Day 34 of the study for tissue analysis. Tissues concentrations of total PAHs from mussels placed in water column and the sediment respectively were at the high site 8.4 and 5.6 mg/Kg, the intermediate site 4.3 and 3.3 mg/Kg and low site 3.2 and 2.7 mg/Kg. The following issues will be addressed; PAH concentration in the tissues compared to site sediment concentrations and the accumulation differences of mussels placed in the water column versus those in the sediment. The data indicate that zebra mussel PAH bioaccumulation potential is of environmental concern.

Roper, J.M. [Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States)]|[USAE Waterways Experiment Station, Vicksburg, MS (United States); Cherry, D.S. [Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States); Simmers, J.W. [USAE Waterways Experiment Station, Vicksburg, MS (United States)

1994-12-31

232

Characterization of metallothionein-like proteins from zebra mussels (Dreissena polymorpha)  

Energy Technology Data Exchange (ETDEWEB)

Zebra mussels (Dreissena polymorpha) are freshwater mollusks that have recently infested the Great Lakes ecosystem. Possessing a large capacity for filtration, these mussel populations act as bioconcentrators for contaminants, such as heavy metals, found in the Great Lakes ecosystem. Metallothionein is a low-molecular-weight, heavy metal-binding protein found in most living organisms. Characterization and partial purification of metallothionein-like Cd-binding proteins from zebra mussels were performed. Zebra mussels were exposed to 500 {micro}g/L Cd for 14 d. During the exposure period, two mussels were removed on alternate days for analysis of Cd-binding proteins. Gel-filtration high-performance liquid chromatography-microatomization-atomic absorption spectrophotometry results showed a single Cd-binding molecular weight protein fraction after 2 d of Cd exposure. After 10 d of Cd exposure, however, mussels exhibited an additional higher molecular weight, Cd-binding protein fraction. The lower molecular weight metallothionein-like Cd-binding protein was further isolated and purified by acetone fractionation, Sephadex G75, and diethylaminoethyl anion-exchange chromatography. The quantities of Zn, Cu, and Cd in the anion-exchange metallothionein-like protein isoforms were determined by inductively coupled plasma-mass spectrometry. The ability to bioconcentrate heavy metals in a metallothionein-like form coupled with their large population in the Great Lakes make zebra mussels suitable for use in a freshwater biomonitoring program for aquatic metal contamination.

High, K.A.; Barthet, V.J.; Blais, J.S. [McGill Univ., Sainte Anne de Bellevue, Quebec (Canada). Dept. of Food Science and Agricultural Chemistry; McLaren, J.W. [National Research Council of Canada, Ottawa, Ontario (Canada)

1997-06-01

233

Pulse power generated electric fields as a means to control zebra mussels  

Energy Technology Data Exchange (ETDEWEB)

In 1994, a study was conducted to determine if pulsed electric fields could reduce zebra mussel settlement rates. The study was a continuation of a study that began in 1991. Several types of fields were generated over the four-year study. The 1994 study concluded that fast rise DC, pulse power signals could stun post-veligers and significantly reduce settlement.

Smythe, A.G.; Lange, C.L.; Doyle, J.F. [Acres International Corporation, Buffalo, NY (United States)] [and others

1995-06-01

234

Role of gender, season, and familiarity in discrimination of conspecific song by zebra finches (Taeniopygia guttata).  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Operant conditioning techniques were used to assess how gender and song familiarity affect song discrimination in adult zebra finches (Taeniopygia guttata). Twenty-five males and females, divided into five cohorts, were trained to discriminate between conspecific songs at different times of year. Ma...

Cynx, J; Nottebohm, F

235

Spatially and Spectrally Resolved Observations of a Zebra Pattern in Solar Decimetric Radio Burst  

CERN Document Server

We present the first interferometric observation of a zebra-pattern radio burst with simultaneous high spectral (~ 1 MHz) and high time (20 ms) resolution. The Frequency-Agile Solar Radiotelescope (FASR) Subsystem Testbed (FST) and the Owens Valley Solar Array (OVSA) were used in parallel to observe the X1.5 flare on 14 December 2006. By using OVSA to calibrate the FST the source position of the zebra pattern can be located on the solar disk. With the help of multi-wavelength observations and a nonlinear force-free field (NLFFF) extrapolation, the zebra source is explored in relation to the magnetic field configuration. New constraints are placed on the source size and position as a function of frequency and time. We conclude that the zebra burst is consistent with a double-plasma resonance (DPR) model in which the radio emission occurs in resonance layers where the upper hybrid frequency is harmonically related to the electron cyclotron frequency in a coronal magnetic loop.

Chen, Bin; Gary, Dale E; Jing, Ju

2011-01-01

236

Preparation and evaluation of biocide-loaded particles to control the biofouling zebra mussel, Dreissena polymorpha  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The freshwater zebra mussel Dreissena polymorpha is a powerful biofouling bivalve, which has tremendous impact on industrial facilities whose operation depends on the intensive use of freshwater, such as waterworks and power stations. The control of the pest in industrial environments remains a majo...

Costa, R.; Aldridge, D. C.; Moggridge, G. D.

237

Flash evoked responses in a song control nucleus of the zebra finch (Taeniopygia guttata castanotis)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The song of the zebra finch is facilitated and altered by the presence of a female. Thus, visual information should affect the song system of the bird. Visually evoked potentials can be recorded from n. hyperstriatum ventrale pars caudale (HVc). The long latency of this potential and its variability...

Bischof, Hans-Joachim; Engelage, Jürgen

238

Cold-induced vasodilation in the brood patch of Zebra finches (Taeniopygia guttata)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The development of the avian embryo is dependent of heat provisioning from the parents. To increase the heat transfer to a cooled egg the Zebra finch females develop a brood patch. Mild cooling generally constricts the blood vessels but the Arterio-venous anastomoses (AVA) in the brood patch in bird...

Klubb, Sofia

239

Zebra Crossing: Walking in Two Continents Sharing and Celebrating Difference through Music  

Science.gov (United States)

|I use the metaphor "zebra crossing" in my reflective narrative to describe my plight and struggle as a non-white person growing up and working in Johannesburg, South Africa, during the apartheid era. This article considers and compares the notions of culture, diversity and identity as I now work in a tertiary institution in Melbourne, Australia.…

Joseph, Dawn

2011-01-01

240

ZEBRA MUSSEL COLONIZATION OF RUSTY CRAYFISH IN GREEN BAY, LAKE MICHIGAN  

Science.gov (United States)

In August, 1995 six rusty crayfish colonized with zebra mussels were captured in small-meshed fyke-nets sets set apart as of a fish sampling effort at Peter's Marsh and Long-Tail Point Wetland in lower Green Bay. Mussels colonized virtually all areas of the crayfish bodies, but ...

 
 
 
 
241

Assessing the potential for fish predation to impact zebra mussels (Dreissena polymorpha): Insight from bioenergetics models  

Science.gov (United States)

Rates of annual food consumption and biomass were modeled for several fish species across representative rivers and lakes in eastern North America. Results were combined to assess the relative potential of fish predation to impact zebra mussels (Dreissena polymorpha). Predicted annual food consumption by fishes in southern waters was over 100% greater than that in northern systems because of warmer annual water temperatures and presumed increases in metabolic demand. Although generally increasing with latitude, biomasses of several key zebra mussel fish predators did not change significantly across latitudes. Biomasses of some less abundant fish predators did increase significantly with latitude, but increases were not of the magnitude to offset predicted decreases in food consumption. Our results generally support the premise that fishes in rivers and lakes of the southern United States (U.S.) have inherently greater potential to impact zebra mussels by predation. Our simulations may provide a partial explanation of why zebra mussel invasions have not been as rapid and widespread in southern U.S. waters compared to the Great Lakes region. ?? Blackwell Munksgaard, 2004.

Eggleton, M. A.; Miranda, L. E.; Kirk, J. P.

2004-01-01

242

The structure of the ZEBRA telescope, the integration tests and the first calibration results  

International Nuclear Information System (INIS)

[en] The ZEBRA telescope is a balloon borne low energy gamma ray instrument, sensitive in the photon energy range 0.2-10MeV. The main characteristics and components of the telescope are described, and its performance during laboratory calibration is discussed, after its integration with the flight electronics

1987-01-01

243

Zebra: a web server for bioinformatic analysis of diverse protein families.  

UK PubMed Central (United Kingdom)

During evolution of proteins from a common ancestor, one functional property can be preserved while others can vary leading to functional diversity. A systematic study of the corresponding adaptive mutations provides a key to one of the most challenging problems of modern structural biology - understanding the impact of amino acid substitutions on protein function. The subfamily-specific positions (SSPs) are conserved within functional subfamilies but are different between them and, therefore, seem to be responsible for functional diversity in protein superfamilies. Consequently, a corresponding method to perform the bioinformatic analysis of sequence and structural data has to be implemented in the common laboratory practice to study the structure-function relationship in proteins and develop novel protein engineering strategies. This paper describes Zebra web server - a powerful remote platform that implements a novel bioinformatic analysis algorithm to study diverse protein families. It is the first application that provides specificity determinants at different levels of functional classification, therefore addressing complex functional diversity of large superfamilies. Statistical analysis is implemented to automatically select a set of highly significant SSPs to be used as hotspots for directed evolution or rational design experiments and analyzed studying the structure-function relationship. Zebra results are provided in two ways - (1) as a single all-in-one parsable text file and (2) as PyMol sessions with structural representation of SSPs. Zebra web server is available at http://biokinet.belozersky.msu.ru/zebra .

Suplatov D; Kirilin E; Takhaveev V; Svedas V

2013-09-01

244

Update on the potato variety screening for zebra chip resistance trial  

Science.gov (United States)

Zebra chip (ZC), a new and economically important disease of potato has caused millions of dollars in losses to the potato industry in the Americas and New Zealand. The disease is associated with the bacterium “Candidatus liberibacter solanacearum” (Lso) that is transmitted to potato by the potato p...

245

The Zurich Extragalactic Bayesian Redshift Analyzer (ZEBRA) and its first application: COSMOS  

CERN Document Server

We present ZEBRA, the Zurich Extragalactic Bayesian Redshift Analyzer. The current version of ZEBRA combines and extends several of the classical approaches to produce accurate photometric redshifts down to faint magnitudes. In particular, ZEBRA uses the template-fitting approach to produce Maximum Likelihood and Bayesian redshift estimates based on: (1.) An automatic iterative technique to correct the original set of galaxy templates to best represent the SEDs of real galaxies at different redshifts; (2.) A training set of spectroscopic redshifts for a small fraction of the photometric sample; and (3.) An iterative technique for Bayesian redshift estimates, which extracts the full two-dimensional redshift and template probability function for each galaxy. We demonstrate the performance of ZEBRA by applying it to a sample of 866 I_AB <= 22.5 COSMOS galaxies with available u*, B, V, g', r', i', z' and K_s photometry and zCOSMOS spectroscopic redshifts in the range 0 < z < 1.3. Adopting a 5-sigma-clipp...

Feldmann, R; Porciani, C; Lilly, S J; Capak, P; Taniguchi, Y; Lefèvre, O; Renzini, A; Scoville, N Z; Ajiki, M; Aussel, H; Contini, T; McCracken, H; Mobasher, B; Murayama, T; Sanders, D; Sasaki, S; Scarlata, C; Scodeggio, M; Shioya, Y; Silverman, Joseph; Takahashi, M; Thompson, D; Zamorani, G

2006-01-01

246

Arousal enhances [14C]2-deoxyglucose uptake in four forebrain areas of the zebra finch  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The activity pattern of the forebrain of male zebra finches was investigated by the [14C]2-deoxyglucose (2-DG) method in 4 different behavioral situations. (1) Sitting alone in the cage (control); (2) courtship by experienced birds; (3) first courtship of inexperienced birds (100 days of age), and (...

Bischof, Hans-Joachim; Herrmann, Kathrin

247

Impact of Zebra Chip Disease on the Mineral Content of Potato Tubers  

Science.gov (United States)

Zebra chip (ZC) is an emerging and damaging disease of potato (Solanum tuberosum L.) that has been documented in potato fields throughout the southwestern United States, Mexico, Central America, and most recently New Zealand. The bacterium “Candidatus Liberibacter” has been putatively identified as ...

248

Vasodilatory effects of exogenous nitric oxide on the brood patch of the Zebra finch (Taeniopygia guttata)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In birds like the Zebra finch (Taeniopygia guttata) the female, but not the male develop a brood patch upon incubation of eggs. The brood patch functions to increase heat exchange between the bird and the eggs. Development of the brood patch includes de-feathering, increased vascularization and edem...

Södergren, Anna

249

The complete genome sequence of ‘Candidatus Liberibacter solanacearum’, the bacterium associated with potato Zebra Chip disease  

Science.gov (United States)

Zebra Chip (ZC) is an emerging plant disease that causes aboveground decline of potato shoots and generally results in unusable tubers. This disease has led to multi-million dollar losses for growers in the central and western United States over the past decade and impacts the livelihood of potato ...

250

Vegetation description of the Doornhoek section of the Mountain Zebra National Park (MZNP), South Africa  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The Mountain Zebra National Park (MZNP) has been extended over the last couple of years. One of the newly procured areas is the Doornhoek section, which had been adjacent to the park. To develop scientifically sound management programmes for conservation areas, it is essential that an inventory of t...

Hugo Bezuidenhout; Leslie R. Brown

251

The Invasion of the Zebra Mussel - Effects on Phytoplankton Community Structure and Ecosystem Function  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Biological invasion has become a major threat to economy, ecology, global biodiversity and ecosystem function of aquatic ecosystems. The main aim of the thesis was to study the effects of the zebra mussel (Dreissena polymorpha), a versatile invasive species, on phytoplankton dynamics and e...

Naddafi, Rahmat

252

TRP channels and regulation of blood flow in the brood patch of Zebra finches (Taeniopygia guttata)  

Digital Repository Infrastructure Vision for European Research (DRIVER)

During the breeding season Zebra finch, Taeniopygia guttata, females develops a brood patch on the ventral surface which facilitates heat exchange between the incubating bird and the egg. The brood patch has to be sensitive to changes in temperature, so that the eggs can be kept at an optimal temper...

Silverå Ejenby, Malin

253

Bird brains and songs : Neural mechanisms of auditory memory and perception in zebra finches  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Songbirds, such as zebra finches, learn their songs from a ‘tutor’ (usually the father), early in life. There are strong parallels between the behavioural, cognitive and neural processes that underlie vocal learning in humans and songbirds. In both cases there is a sensitive period for auditory lear...

Gobes, S.M.H.

254

Zebra: Searching for Rare Diseases : A Case of Task-Based Search in the Medical Domain  

DEFF Research Database (Denmark)

Task-based search addresses situations where standard off-the-shelf Information Retrieval (IR) technology may not suffice to satisfy users in their tasks. In these situations, IR systems should be tailored to the user’s task-specific needs and requirements. One such task is searching for rare disease diagnostic hypotheses in the domain of medical IR. In this work, we build upon an existing vertical medical search engine, Zebra, that is focused on rare disease diagnosis. In previous work, Zebra has been evaluated using real-life medical cases of rare and difficult diseases, and has been found to be a useful and competitive tool for clinicians. In this work, we extend Zebra’s functionalities to optimise the task of medical diagnosis through search as follows: we add the option of grouping retrieved documents into clusters based on disease name occurrence, and we offer a ‘disease-ranking’ option, in addition to the standard ‘document-ranking’ option. This paper presents and discusses these functionalities.

Dragusin, Radu; Petcu, Paula

2012-01-01

255

SPATIALLY AND SPECTRALLY RESOLVED OBSERVATIONS OF A ZEBRA PATTERN IN A SOLAR DECIMETRIC RADIO BURST  

International Nuclear Information System (INIS)

We present the first interferometric observation of a zebra-pattern radio burst with simultaneous high spectral (?1 MHz) and high time (20 ms) resolution. The Frequency-Agile Solar Radiotelescope Subsystem Testbed (FST) and the Owens Valley Solar Array (OVSA) were used in parallel to observe the X1.5 flare on 2006 December 14. By using OVSA to calibrate the FST, the source position of the zebra pattern can be located on the solar disk. With the help of multi-wavelength observations and a nonlinear force-free field extrapolation, the zebra source is explored in relation to the magnetic field configuration. New constraints are placed on the source size and position as a function of frequency and time. We conclude that the zebra burst is consistent with a double-plasma resonance model in which the radio emission occurs in resonance layers where the upper-hybrid frequency is harmonically related to the electron cyclotron frequency in a coronal magnetic loop.

2011-07-20

256

Annotated Check List of the Spiders (Araneae) of the Mountain Zebra National Park  

Directory of Open Access Journals (Sweden)

Full Text Available A preliminary check list of the spider fauna of the Mountain Zebra National Park is given. Sixteen families, comprising 29 genera and 32 species, are recorded. Observations on the distribution, diagnostic morphology and behaviour of 15 species are given.

Anna S. Dippenaar-Schoeman

1988-01-01

257

Spatially and Spectrally Resolved Observations of a Zebra Pattern in a Solar Decimetric Radio Burst  

Science.gov (United States)

We present the first interferometric observation of a zebra-pattern radio burst with simultaneous high spectral (?1 MHz) and high time (20 ms) resolution. The Frequency-Agile Solar Radiotelescope Subsystem Testbed (FST) and the Owens Valley Solar Array (OVSA) were used in parallel to observe the X1.5 flare on 2006 December 14. By using OVSA to calibrate the FST, the source position of the zebra pattern can be located on the solar disk. With the help of multi-wavelength observations and a nonlinear force-free field extrapolation, the zebra source is explored in relation to the magnetic field configuration. New constraints are placed on the source size and position as a function of frequency and time. We conclude that the zebra burst is consistent with a double-plasma resonance model in which the radio emission occurs in resonance layers where the upper-hybrid frequency is harmonically related to the electron cyclotron frequency in a coronal magnetic loop.

Chen, Bin; Bastian, T. S.; Gary, D. E.; Jing, Ju

2011-07-01

258

Zebra mussel antifouling activity of the marine natural product aaptamine and analogs.  

UK PubMed Central (United Kingdom)

Several aaptamine derivatives were selected as potential zebra mussel (Dreissena polymorpha) antifoulants because of the noteworthy absence of fouling observed on Aaptos sponges. Sponges of the genus Aaptos collected in Manado, Indonesia consistently produce aaptamine-type alkaloids. To date, aaptamine and its derivatives have not been carefully evaluated for their antifoulant properties. Structure-activity relationship studies were conducted using several aaptamine derivatives in a zebra mussel antifouling assay. From these data, three analogs have shown significant antifouling activity against zebra mussel attachment. Aaptamine, isoaaptamine, and the demethylated aaptamine compounds used in the zebra mussel assay produced EC(50) values of 24.2, 11.6, and 18.6 microM, respectively. In addition, neither aaptamine nor isoaaptamine produced a phytotoxic response (as high as 300 microM) toward a nontarget organism, Lemna pausicostata, in a 7-day exposure. The use of these aaptamine derivatives from Aaptos sp. as potential environmentally benign antifouling alternatives to metal-based paints and preservatives is significant, not only as a possible control of fouling organisms, but also to highlight the ecological importance of these and similar biochemical defenses.

Diers JA; Bowling JJ; Duke SO; Wahyuono S; Kelly M; Hamann MT

2006-07-01

259

Matrilin-like molecules produced by circulating hemocytes of the zebra mussel (Dreissena polymorpha) upon stimulation.  

UK PubMed Central (United Kingdom)

Since invading the Great Lakes basin, USA, in 1980s, the zebra mussel (Dreissena polymorpha) has caused significant economic and ecologic devastation. The absence of major diseases led to the belief that zebra mussel may have extraordinary host defense mechanisms. This study was undertaken in order to better understand zebra mussel hemocyte functions. A suppressive subtraction hybridization (SSH) cDNA library was constructed from naïve and stimulated hemocytes. Stimulation was performed using a mixture of lipopolysacchride (LPS), peptidoglycan (PGN), and zymosan (ZYM). In the stimulated hemocyte SHH cDNA library, 55 assembled ESTs were differentially expressed. These ESTs contained two putative immune- related molecules, namely, matrilin and agglutinin, three house-keeping genes, six cell metabolism/development genes, and 44 ESTs without putative functions. One of the putative adhesive molecules (CN-29, accession number: AM503947) was predicted to have homology with matrilins including the Von Willebrand Factor A (VWA) domain, which was identical to a matrilin molecule recently reported from the freshwater snail, Biomphalaria glabrata. Preliminary evidence suggests that the zebra mussel matrilin-like molecule is inducible upon hemocyte stimulation.

Xu W; Faisal M

2007-01-01

260

Cultivation of zebra mussels (Dreissena polymorpha) within their invaded range to improve water quality in reservoirs.  

UK PubMed Central (United Kingdom)

Algal and cyanobacterial blooms in reservoirs are driven by nutrient enrichment and may present economic and conservation challenges for water managers. Current approaches such as suppression of algal growth with barley straw, ferric dosing or manipulation of fish stocks have not yielded long term successes. A possibility that has sparked growing interest is the encouragement and cultivation of natural filter feeders, such as mussels, which remove suspended matter from the water and reduce nutrient levels through biodeposition and assimilation. This review focusses on the zebra mussel (Dreissena polymorpha) as a tool for enhancement of water quality in reservoirs. Native to the Ponto-Caspian region, this species has invaded many lakes and reservoirs across North America and Western Europe, where it occurs in very high densities. While purposeful introduction of a non-native species into new sites is socially unacceptable, we investigate the possible benefits of encouraging increased abundance of zebra mussels in sites where the species is already established. We estimate that the annual nitrogen and phosphorus input into a large UK reservoir (Grafham Water) could be assimilated into zebra mussel biomass by encouraging settlement onto 3075 m and 1400 m of commercial mussel ropes, respectively. While zebra mussel cultivation has an incredible capacity to push eutrophic systems towards a clear water state, there are many risks associated with encouraging an invasive species, even within sites where it has already established. The zebra mussel is a prominent biofouler of native unionid mussels and raw water pipes, it changes the physical characteristics of the places it inhabits, in sites low in phosphorus it can be responsible for toxic cyanobacterial blooms, it alters nutrient cycling and community structure and it can have negative impacts on amenity value. Increased propagule pressure from elevated numbers of veliger larvae in the water column may increase the risk of spread to other locations. This may render some reservoir systems, such as dammed rivers which have outflows to downstream watercourses, unsuitable for cultivation. Such reservoirs are especially common in North America. We consider the practicalities of putting a zebra mussel cultivation system into place and identify gaps in knowledge. We conclude that zebra mussel cultivation offers an attractive tool for managing nutrient-enriched reservoirs, but that the benefits and costs must be balanced on a site-by-site basis.

McLaughlan C; Aldridge DC

2013-09-01

 
 
 
 
261

Cultivation of zebra mussels (Dreissena polymorpha) within their invaded range to improve water quality in reservoirs.  

Science.gov (United States)

Algal and cyanobacterial blooms in reservoirs are driven by nutrient enrichment and may present economic and conservation challenges for water managers. Current approaches such as suppression of algal growth with barley straw, ferric dosing or manipulation of fish stocks have not yielded long term successes. A possibility that has sparked growing interest is the encouragement and cultivation of natural filter feeders, such as mussels, which remove suspended matter from the water and reduce nutrient levels through biodeposition and assimilation. This review focusses on the zebra mussel (Dreissena polymorpha) as a tool for enhancement of water quality in reservoirs. Native to the Ponto-Caspian region, this species has invaded many lakes and reservoirs across North America and Western Europe, where it occurs in very high densities. While purposeful introduction of a non-native species into new sites is socially unacceptable, we investigate the possible benefits of encouraging increased abundance of zebra mussels in sites where the species is already established. We estimate that the annual nitrogen and phosphorus input into a large UK reservoir (Grafham Water) could be assimilated into zebra mussel biomass by encouraging settlement onto 3075 m and 1400 m of commercial mussel ropes, respectively. While zebra mussel cultivation has an incredible capacity to push eutrophic systems towards a clear water state, there are many risks associated with encouraging an invasive species, even within sites where it has already established. The zebra mussel is a prominent biofouler of native unionid mussels and raw water pipes, it changes the physical characteristics of the places it inhabits, in sites low in phosphorus it can be responsible for toxic cyanobacterial blooms, it alters nutrient cycling and community structure and it can have negative impacts on amenity value. Increased propagule pressure from elevated numbers of veliger larvae in the water column may increase the risk of spread to other locations. This may render some reservoir systems, such as dammed rivers which have outflows to downstream watercourses, unsuitable for cultivation. Such reservoirs are especially common in North America. We consider the practicalities of putting a zebra mussel cultivation system into place and identify gaps in knowledge. We conclude that zebra mussel cultivation offers an attractive tool for managing nutrient-enriched reservoirs, but that the benefits and costs must be balanced on a site-by-site basis. PMID:23764587

McLaughlan, C; Aldridge, D C

2013-05-07

262

Robotic removal of zebra mussel accumulations in a nuclear power plant screenhouse  

Energy Technology Data Exchange (ETDEWEB)

Zebra mussel accumulations in the power plant intake system have increased over the last four years and have become a maintenance issue. Several treatment methods have been used, including mechanical cleaning by divers. This is limited to areas of relatively low flow velocity. Various sections of the screenhouse are not accessible except during an outage or when one of the intake tunnels can be otherwise be blocked and flow reduced. In addition, diver services are relatively costly. For the above reasons, the Indiana Michigan Power Co., Cook Nuclear Plant, contracted with ARD Environmental Inc. to develop and test a robotic system as an alternative to cleaning by divers. The first phase of this project addressed the requirement to clean the screenhouse floor in all areas, including those with high flow velocity. Subsequent phases will address robotic cleaning of other areas of the intake and the screenhouse structures. The objectives of the project were to: (1) Demonstrate the ability to deploy and retrieve a modified XT1000 vehicle in the inlet bay and screen bays; (2) Remove the accumulations of zebra mussels and possibly other pumpable material from the floor; (3) Reduce or eliminate the need for diver services and reduce overall cost of removing accumulations of zebra mussels; and, (4) Critique operations and develop recommendations for further enhancements to the robotic equipment and materials handling system. Implementation of the operating plan commenced on September 8, 1994, and was completed on October 7, 1994. The project demonstrated that robotic techniques are an efficient and cost effective alternative to diver operations for mechanical removal of zebra mussels. In particular, the robotic system was able to operate effectively in the high flow velocity areas including those at the intake tunnels. The ability to operate in the high flow areas means that zebra mussel removal may take place at any time, without affecting normal plant operations.

Kotler, S.R. [ARD Environmental, Inc., Columbia, MD (United States); Mallen, E.C. [Indiana Michigan Power Co./Cook Nuclear Plant, Bridgman, MI (United States); Tamms, K.M.

1995-06-01

263

Evaluation of the use of chlorine dioxide to control zebra mussels  

Energy Technology Data Exchange (ETDEWEB)

Chlorine dioxide was tested as a zebra mussel biocide at two steam electric generating stations in Illinois. The purpose of these studies was to determine the efficacy of chlorine dioxide in killing zebra mussels and to develop site specific treatment programs for the two utilities. The Electric Power Research Institute (EPRI) Zebra Mussel Consortium sponsored the testing of this recent use of chlorine dioxide. The raw water system at Central Illinois Public Service`s Meredosia Station, on the Illinois River, received two to four day applications of chlorine dioxide in April, July, and September 1994. The raw water system at Illinois Power Company`s Wood River Station, on the Mississippi River, received two to four day applications in July 1993, January, April, May, July, and September 1994. Chlorine dioxide was generated on-site and injected into the water intake structure, in front of or just behind the traveling screens, at both power stations. Both cooling and service water systems were treated at the facilities. Various water quality parameters, including residual chlorine in the discharge effluent, were measured during the studies. Residual chlorine was neutralized with sodium bisulfite prior to discharge at both plants. Bioboxes, containing healthy zebra mussels, were placed at various strategic locations throughout the power stations. Control bioboxes were also placed in the rivers, upstream of the chlorine dioxide injection locations. Results of the chlorine dioxide applications varied from 35 percent to 100 percent. These varied results appear to be related to seasonal water temperature differences, water quality, and/or plant design. Mortality differences were also noted in bioboxes which contained zebra mussels imported from Lake Erie and those which contained local mussels. These and other data are presented.

Tsou, J. [Electric Power Research Institute, Palo Alto, CA (United States); Coyle, J. [Central Illinois Public Service, Meredosia, IL (United States); Pallo, S. [Illinois Power Company, Clinton, IL (United States)] [and others

1995-06-01

264

Strategies to control zebra mussel fouling at Kewaunee Nuclear Power Plant  

International Nuclear Information System (INIS)

[en] The zebra mussel, Dreissena polymorpha, is currently infesting the Great Lakes. First discovered in Lake St. Clair, it is now widespread in Lakes Erie and Ontario. The initial efforts relating to zebra mussel control at Wisconsin Public Service Corporation's (WPSC) Kewaunee Nuclear Power Plant (KNPP) precipitated from the Nuclear Regulatory Commission's (NRC) Generic Letter 89-13 regarding fouling of service water (SW) systems at nuclear power plants. In the summer of 1990, Stone and Webster Engineering Corporation (Stone and Webster) was contracted to perform an evaluation of known problems within the SW system. The purposes of the study were to evaluate the actual and potential magnitude of these problems, to evaluate corrective actions to resolve the problems, and to prepare recommendations which would adequately address the issues. Two of the recommendations of this study were to continue a zebra mussel monitoring program which WPSC had already implemented and to evaluate various biocide injection programs should one be required for zebra mussel control. The concern of utilities operating power stations which use waters infested with zebra mussels as their source of cooling and/or makeup water is that mussels (both adults and veligers) will enter plant water systems and foul piping and heat exchangers. This type of fouling can restrict flow through piping, process equipment, and heat exchangers. This type of fouling can restrict flow through piping, process equipment, and heat exchangers, thereby increasing head losses and reducing heat transfer capabilities. The greatest concern in that fouling of this type is within safety-related piping and equipment that are components of service water systems at nuclear power plants

1992-01-01

265

Ontogeny of adaptive antibody response to a model antigen in captive altricial zebra finches.  

UK PubMed Central (United Kingdom)

Based on studies from the poultry literature, all birds are hypothesized to require at least 4 weeks to develop circulating mature B-cell lineages that express functionally different immunoglobulin specificities. However, many altricial passerines fledge at adult size less than four weeks after the start of embryonic development, and therefore may experience a period of susceptibility during the nestling and post-fledging periods. We present the first study, to our knowledge, to detail the age-related changes in adaptive antibody response in an altricial passerine. Using repeated vaccinations with non-infectious keyhole limpet hemocyanin (KLH) antigen, we studied the ontogeny of specific adaptive immune response in altricial zebra finches Taeniopygia guttata. Nestling zebra finches were first injected at 7 days (7d), 14 days (14d), or 21 days post-hatch (21d) with KLH-adjuvant emulsions, and boosted 7 days later. Adults were vaccinated in the same manner. Induced KLH-specific IgY antibodies were measured using ELISA. Comparisons within age groups revealed no significant increase in KLH-specific antibody levels between vaccination and boost in 7d birds, yet significant increases between vaccination and boost were observed in 14d, 21d, and adult groups. There was no significant difference among age groups in KLH antibody response to priming vaccination, yet KLH antibody response post-boost significantly increased with age among groups. Post-boost antibody response in all nestling age groups was significantly lower than in adults, indicating that mature adult secondary antibody response level was not achieved in zebra finches prior to fledging (21 days post-hatch in zebra finches). Findings from this study contribute fundamental knowledge to the fields of developmental immunology and ecological immunology and strengthen the utility of zebra finches as a model organism for future studies of immune ontogeny.

Killpack TL; Karasov WH

2012-01-01

266

Robotic removal of zebra mussel accumulations in a nuclear power plant screenhouse  

International Nuclear Information System (INIS)

Zebra mussel accumulations in the power plant intake system have increased over the last four years and have become a maintenance issue. Several treatment methods have been used, including mechanical cleaning by divers. This is limited to areas of relatively low flow velocity. Various sections of the screenhouse are not accessible except during an outage or when one of the intake tunnels can be otherwise be blocked and flow reduced. In addition, diver services are relatively costly. For the above reasons, the Indiana Michigan Power Co., Cook Nuclear Plant, contracted with ARD Environmental Inc. to develop and test a robotic system as an alternative to cleaning by divers. The first phase of this project addressed the requirement to clean the screenhouse floor in all areas, including those with high flow velocity. Subsequent phases will address robotic cleaning of other areas of the intake and the screenhouse structures. The objectives of the project were to: (1) Demonstrate the ability to deploy and retrieve a modified XT1000 vehicle in the inlet bay and screen bays; (2) Remove the accumulations of zebra mussels and possibly other pumpable material from the floor; (3) Reduce or eliminate the need for diver services and reduce overall cost of removing accumulations of zebra mussels; and, (4) Critique operations and develop recommendations for further enhancements to the robotic equipment and materials handling system. Implementation of the operating plan commenced on September 8, 1994, and was completed on October 7, 1994. The project demonstrated that robotic techniques are an efficient and cost effective alternative to diver operations for mechanical removal of zebra mussels. In particular, the robotic system was able to operate effectively in the high flow velocity areas including those at the intake tunnels. The ability to operate in the high flow areas means that zebra mussel removal may take place at any time, without affecting normal plant operations.

267

Stoichiometric constraints do not limit successful invaders: zebra mussels in Swedish lakes.  

UK PubMed Central (United Kingdom)

BACKGROUND: Elemental imbalances of carbon (C): nitrogen (N): phosphorus (P) ratios in food resources can constrain the growth of grazers owning to tight coupling between growth rate, RNA allocation and biomass P content in animals. Testing for stoichiometric constraints among invasive species is a novel challenge in invasion ecology to unravel how a successful invader tackles ecological barriers in novel ecosystems. METHODOLOGY/PRINCIPAL FINDINGS: We examined the C:P and N:P ratios and the condition factor of a successful invader in lakes, the zebra mussel (Dreissena polymorpha), collected from two Swedish lakes. Concurrently, we analyzed the elemental composition of the food (seston) and tissue of the mussels in which nutrient composition of food and mussels varied over time. Zebra mussel condition factor was weakly related to the their own tissue N:P and C:P ratios, although the relation with the later ratio was not significant. Smaller mussels had relatively lower tissue N:P ratio and higher condition factor. There was no difference in C:P and N:P ratios between seston and mussels' tissues. Our results indicated that the variation in nutrient stoichiometry of zebra mussels can be explained by food quality and quantity. CONCLUSIONS/SIGNIFICANCE: Our study suggests that fitness of invasive zebra mussels is not constrained by nutrient stoichiometry which is likely to be important for their proliferation in novel ecosystems. The lack of imbalance in C:P and N:P ratios between seston and mussels along with high tissue C:P ratio of the mussel allow them to tolerate potential P limitation and maintain high growth rate. Moreover, zebra mussels are able to change their tissue C:P and N:P ratios in response to the variation in elemental composition of their food. This can also help them to bypass potential nutrient stoichiometric constraints. Our finding is an important step towards understanding the mechanisms contributing to the success of exotic species from stoichiometric principles.

Naddafi R; Eklöv P; Pettersson K

2009-01-01

268

ASSESSING THE IMPACT OF CONTINUOUS BACTERIAL TREATMENTS OVER A TWO-WEEK PERIOD ON ZEBRA MUSSEL MORTALITY  

Energy Technology Data Exchange (ETDEWEB)

These experiments indicated that in waters at 23 C the window of opportunity to kill zebra mussels with bacterial strain CL0145A is limited to the first two days of treatment. Treatments beyond two days will not increase mortality.

Daniel P. Molloy

2001-07-17

269

The ZEBRA battery: functioning, test results, economic aspects and efficiency for the use of hybrid vehicles; Die ZEBRA-Batterie: Funktion, Testergebnisse, wirtschaftliche Aspekte und Effizienz fuer den Einsatz in Hybridfahrzeugen  

Energy Technology Data Exchange (ETDEWEB)

The ZEBRA battery is a high energy store based on the electrochemical system Na/NiCl{sub 2}. Against the background that the ZEBRA battery has already proved successful in electric vehicles, the battery system is described with regard to its possible use in hybrid vehicles. The analysis of its economics shows that the operating costs of hybrid vehicles always lie between those of the internal combustion engine and those of electric vehicles. The hybrid vehicle is therefore an alternative, which combines the advantages of a large range and clean driving. Based on the introduced features of the ZEBRA battery, this energy store can be used most efficiently in the hybrid range in vehicles with a high degree of use (commercial vehicles). (orig.) [Deutsch] Die ZEBRA Batterie ist ein Hochenergiestromspeicher auf der Basis des elektrochemsichen Systems Na/NiCl{sub 2}. Vor dem Hintergrund, dass sich die ZEBRA Batterie in Elektrofahrzeugen bereits bewaehrt hat, wird das Batteriesystem in Hinblick auf seine Einsatzmoeglichkeiten in Hybridfahrzeugen beschrieben. Die Wirtschaftlichkeitsanalyse zeigt, dass die Betriebskosten von Hybridfahrzeugen immer zwischen denen des Verbrennungsmotor- und denen des Elektrofahrzeug liegen. Das Hybridfahrzeug ist damit eine Alternative, die die Vorteile Reichweite und sauberes Fahren verbindet. Auf der Basis der vorgestellten Merkmale der ZEBRA Batterie kann dieser Energiespeicher im Hybridbereich am effizientesten in Fahrzeugen mit hohem Nutzungsgrad eingesetzt werden. (orig.)

Gemmeke, M.; Dustmann, C.M.

1995-12-31

270

Effect of the zebra mussel (Dreissena polymorpha) on food-chain transfer of PCBs in Saginaw Bay  

Energy Technology Data Exchange (ETDEWEB)

The recent invasion of the zebra mussel (Dreissena polymorpha) has significantly impacted the water quality of the Great Lakes. Relatively little is known about the influence of zebra mussels on contaminant cycling, and transfer to higher trophic organisms. Due to its high filtering rate and ability to rapidly establish large populations, Dreissena could potentially alter the flow of energy through the food web. In addition, this species has demonstrated a large capacity for accumulating lipophilic organic contaminants such as polychlorinated biphenyls (PCBs). Thus, zebra mussels could contribute to enhanced contaminant biomagnification by serving as an additional food-chain link either through direct transfer (ingestion by fish or ducks), and/or indirectly by funneling contaminants out of the pelagic zone down to benthic invertebrates. In order to determine if zebra mussels are enhancing biomagnification of PCBs in a Saginaw Bay food web, two years of field collections of various components (water, sediment, algae, zooplankton, zebra mussel, zebra mussel feces, gammarid amphipods, fish) were analyzed for their PCB congener content. Trophic levels will be characterized using stable isotope ratios of {sup 15}N/{sup 14}N, whereas carbon sources will be identified using {sup 13}C/{sup 13}C ratios.

Hoof, P.L. Van; Hsieh, J.L.; Eadie, B.J.; Lansing, M.B. [NOAA, Ann Arbor, MI (United States). Great Lakes Environmental Research Lab.

1995-12-31

271

Comparative genomic analysis of the zebra finch degradome provides new insights into evolution of proteases in birds and mammals  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background The degradome -the complete repertoire of proteases in an organism- is involved in multiple key biological and pathological processes. Previous studies in several organisms have yielded sets of curated protease sequences which may be used to characterize the degradome in a novel genome by similarity. Differences between degradomes can then be related to physiological traits of the species under study. Therefore, the sequencing of the zebra finch genome allows the comparison between the degradomes of mammals and birds and may help to understand the biological peculiarities of the zebra finch. Results A set of curated protease sequences from humans and chicken was used to predict the sequences of 460 protease and protease-like genes in the zebra finch genome. This analysis revealed important differences in the evolution of mammalian and bird degradomes, including genomic expansions and deletions of caspases, cytotoxic proteases, kallikreins, matrix metalloproteases, and trypsin-like proteases. Furthermore, we found several zebra finch-specific features, such as duplications in CASP3 and BACE, and a large genomic expansion of acrosin. Conclusions We have compared the degradomes of zebra finch, chicken and several mammalian species, with the finding of multiple differences which illustrate the evolution of the protease complement of these organisms. Detailed analysis of these changes in zebra finch proteases has shown that they are mainly related to immunological, developmental, reproductive and neural functions.

Quesada Víctor; Velasco Gloria; Puente Xose S; Warren Wesley C; López-Otín Carlos

2010-01-01

272

The ZEBRA electric vehicle battery: power and energy improvements  

Energy Technology Data Exchange (ETDEWEB)

Vehicle trials with the first sodium/nickel chloride ZEBRA batteries indicated that the pulse power capability of the battery needed to be improved towards the end of the discharge. A research programme led to several design changes to improve the cell which, in combination, have improved the power of the battery to greater than 150 W kg{sup -1} at 80% depth of discharge. Bench and vehicle tests have established the stability of the high power battery over several years of cycling. The gravimetric energy density of the first generation of cells was less than 100 Wh kg{sup -1}. Optimisation of the design has led to a cell with a specific energy of 120 Wh kg{sup -1} or 86 Wh kg{sup -1} for a 30 kWh battery. Recently, the cell chemistry has been altered to improve the useful capacity. The cell is assembled in the over-discharged state and during the first charge the following reactions occur: at 1.6 V: Al + 4NaCl = NaAlCl{sub 4} + 3Na; at 2.35 V: Fe + 2NaCl = FeCl{sub 2} + 2Na; at 2.58 V: Ni + 2NaCl = NiCl{sub 2} + 2 Na. The first reaction serves to prime the negative sodium electrode but occurs at too low a voltage to be of use in providing useful capacity. By minimising the aluminium content more NaCl is released for the main reactions to improve the capacity of the cell. This, and further composition optimisation, have resulted in cells with specific energies in excess of 140 Wh kg{sup -1}, which equates to battery energies > 100 Wh kg{sup -1}. The present production battery, as installed in a Mercedes Benz A class electric vehicle, gives a driving range of 205 km (128 miles) in city and hill climbing. The cells with improved capacity will extend the practical driving range to beyond 240 km (150 miles). (orig.)

Galloway, R.C.; Haslam, S. [Beta Research and Development, Sinfin (United Kingdom)

1999-07-01

273

Gene expression profiling during the byssogenesis of zebra mussel (Dreissena polymorpha).  

UK PubMed Central (United Kingdom)

Since its invasion to the North American waters 20 years ago, the zebra mussel (Dreissena polymorpha) has negatively impacted the ecosystems through its firm underwater adhesion. The molecular mechanisms governing the functions of the zebra mussel byssus, the main structure responsible for maintaining the underwater adhesion, have received little attention. Our previously developed zebra mussel foot byssus cDNA microarray was applied in this study to identify the genes involved in different stages of the byssal threads generation. Byssal threads of zebra mussels were manually severed under laboratory conditions and the formation of new byssal threads was followed over a 3 week course. By comparing the gene expression profiles in different stages of byssal threads generation (byssogenesis) to their baseline values, we found that the number of unique byssus genes differentially expressed at 12-h, 1, 2, 3, 4, 7, and 21 days post-treatment was 13, 13, 20, 17, 16, 20, and 29, respectively. Comparisons were also made between two subsequent samples (e.g., 12 h vs. 1, 1 vs. 2 days, 2 vs. 3 days, and so on). Seven differentially expressed genes were selected for validation by using quantitative reverse transcription PCR (qRT-PCR) and the results were consistent with those from the microarray analysis. By using fluorescent in situ hybridization, we found that two microarray identified genes, BG15_F03-DPFP and BG16_H05-EGP, were expressed in two major byssus glands located in the zebra mussel foot: the stem-forming gland and plaque-forming gland, respectively. Moreover, the qRT-PCR of seven microarray identified genes with different zebra mussel samples suggested that they were also expressed in other mussel tissues beside the foot, albeit at much lower levels. This suggested that the microarray identified genes were produced primarily by the foot, and were likely associated with byssogenesis. The differentially expressed genes identified in this study indicated that multiple molecules are involved in byssogenesis, most likely performing multiple functions during the generation of byssal threads. These results obtained herein represent the first logical step toward understanding underwater attachment mechanisms employed by this invasive species.

Xu W; Faisal M

2010-04-01

274

Factorial microarray analysis of zebra mussel (Dreissena polymorpha: Dreissenidae, Bivalvia) adhesion  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background The zebra mussel (Dreissena polymorpha) has been well known for its expertise in attaching to substances under the water. Studies in past decades on this underwater adhesion focused on the adhesive protein isolated from the byssogenesis apparatus of the zebra mussel. However, the mechanism of the initiation, maintenance, and determination of the attachment process remains largely unknown. Results In this study, we used a zebra mussel cDNA microarray previously developed in our lab and a factorial analysis to identify the genes that were involved in response to the changes of four factors: temperature (Factor A), current velocity (Factor B), dissolved oxygen (Factor C), and byssogenesis status (Factor D). Twenty probes in the microarray were found to be modified by one of the factors. The transcription products of four selected genes, DPFP-BG20_A01, EGP-BG97/192_B06, EGP-BG13_G05, and NH-BG17_C09 were unique to the zebra mussel foot based on the results of quantitative reverse transcription PCR (qRT-PCR). The expression profiles of these four genes under the attachment and non-attachment were also confirmed by qRT-PCR and the result is accordant to that from microarray assay. The in situ hybridization with the RNA probes of two identified genes DPFP-BG20_A01 and EGP-BG97/192_B06 indicated that both of them were expressed by a type of exocrine gland cell located in the middle part of the zebra mussel foot. Conclusions The results of this study suggested that the changes of D. polymorpha byssogenesis status and the environmental factors can dramatically affect the expression profiles of the genes unique to the foot. It turns out that the factorial design and analysis of the microarray experiment is a reliable method to identify the influence of multiple factors on the expression profiles of the probesets in the microarray; therein it provides a powerful tool to reveal the mechanism of zebra mussel underwater attachment.

Xu Wei; Faisal Mohamed

2010-01-01

275

Factorial microarray analysis of zebra mussel (Dreissena polymorpha: Dreissenidae, Bivalvia) adhesion.  

UK PubMed Central (United Kingdom)

BACKGROUND: The zebra mussel (Dreissena polymorpha) has been well known for its expertise in attaching to substances under the water. Studies in past decades on this underwater adhesion focused on the adhesive protein isolated from the byssogenesis apparatus of the zebra mussel. However, the mechanism of the initiation, maintenance, and determination of the attachment process remains largely unknown. RESULTS: In this study, we used a zebra mussel cDNA microarray previously developed in our lab and a factorial analysis to identify the genes that were involved in response to the changes of four factors: temperature (Factor A), current velocity (Factor B), dissolved oxygen (Factor C), and byssogenesis status (Factor D). Twenty probes in the microarray were found to be modified by one of the factors. The transcription products of four selected genes, DPFP-BG20_A01, EGP-BG97/192_B06, EGP-BG13_G05, and NH-BG17_C09 were unique to the zebra mussel foot based on the results of quantitative reverse transcription PCR (qRT-PCR). The expression profiles of these four genes under the attachment and non-attachment were also confirmed by qRT-PCR and the result is accordant to that from microarray assay. The in situ hybridization with the RNA probes of two identified genes DPFP-BG20_A01 and EGP-BG97/192_B06 indicated that both of them were expressed by a type of exocrine gland cell located in the middle part of the zebra mussel foot. CONCLUSIONS: The results of this study suggested that the changes of D. polymorpha byssogenesis status and the environmental factors can dramatically affect the expression profiles of the genes unique to the foot. It turns out that the factorial design and analysis of the microarray experiment is a reliable method to identify the influence of multiple factors on the expression profiles of the probesets in the microarray; therein it provides a powerful tool to reveal the mechanism of zebra mussel underwater attachment.

Xu W; Faisal M

2010-01-01

276

Lake Erie and Lake Michigan zebra mussel settlement monitoring and implications for chlorination treatment  

Energy Technology Data Exchange (ETDEWEB)

This paper reports on the 1991 zebra mussel veliger settlement monitoring program undertaken to record and evaluate zebra mussel veliger settlement in Lake Erie and Lake Michigan. Studies by Dr. Gerald Mackie of Canada in 1990 indicated veliger settlement may be occurring primarily during short time periods every season corresponding with warmer water temperatures. Veliger settlement monitoring was performed using a plexiglass sampler apparatus. The samplers were simple in design and consisted of a 20-inch-square plexiglass base panel with thirty-six 1 inch {times} 3 inch clear plexiglass microscope slides attached. The results of the monitoring program indicate the existence of preferential settlement periods for veligers correlating with sustained lake water temperatures above 70{degrees}F. Veliger settlement concentrations in the south basin of Lake Michigan appear to be similar to those in western Lake Erie.

Demoss, D.; Mendelsberg, J.I. (Sargent and Lundy, Chicago, IL (US))

1992-01-01

277

Cross-effects of nickel contamination and parasitism on zebra mussel physiology.  

UK PubMed Central (United Kingdom)

Aquatic organisms are exposed to pollution which may make them more susceptible to infections and diseases. The present investigation evaluated effects of nickel contamination and parasitism (ciliates Ophryoglena spp. and intracellular bacteria Rickettsiales-like organisms), alone and in combination, on biological responses of the zebra mussel Dreissena polymorpha, and also the infestation abilities of parasites, under laboratory controlled conditions. Results showed that after 48 h, more organisms were infected in nickel-exposed groups, which could be related to weakening of their immune system. Acting separately, nickel contamination and infections were already stressful conditions; however, their combined action caused stronger biological responses in zebra mussels. Our data, therefore, confirm that the parasitism in D. polymorpha represents a potential confounding factor in ecotoxicological studies that involve this bivalve.

Minguez L; Boiché A; Sroda S; Mastitsky S; Brulé N; Bouquerel J; Giambérini L

2012-03-01

278

Bioaccumulation of polychlorinated biphenyls by zebra mussel populations predicted on the basis of bioenergetics  

Energy Technology Data Exchange (ETDEWEB)

Hydrophobic organic contaminants, such as PCBs, partition between several phases in aquatic environments. In order to predict contaminant partitioning and flux rates between aquatic biota and other environmental phases, it is necessary to have a basic understanding of the physico-chemical properties characteristic of the contaminant of interest, in addition to exposure rates of organisms to various contaminated phases. Exposure regimes are often dictated by food availability and corresponding feeding rates necessary to meet organism energetic requirements. Therefore, a model coupling zebra mussel bioenergetics and predicted PCB bioaccumulation has been constructed to assess the impact of zebra mussel populations on organic contaminant transfer in freshwater systems. The potential impact of mussel populations on organic contaminant transfer and energy flow will be discussed.

Yankovich, T. [Trent Univ., Peterborough, Ontario (Canada)

1995-12-31

279

Protocol for conducting sediment bioassays with materials potentially containing zebra mussels (dreissena polymorpha). Final report  

Energy Technology Data Exchange (ETDEWEB)

The zebra mussel, Dreissena polymorpha, was introduced in United States waters accidentally in 1985 and has since become a major nuisance organism. Although many waters have become infested and distribution of the organism has become widespread, procedures are being developed to avoid release in waters that are not infested and to avoid additional release in those that are already infested. Techniques and procedures to avoid the unintentional release of the nonindigenous species during conduct of bioassays are discussed. This protocol contains methods for receiving and handling sediment and/or water samples used in bioassays that may potentially contain zebra mussels. Facility design, personnel requirements, effective treatments, and emergency guidelines are presented in the report.

Sims, J.G.; Gamble, E.; Moore, D.W.

1995-02-01

280

Haplosporidium raabei n. sp. (Haplosporidia): a parasite of zebra mussels, Dreissena polymorpha (Pallas, 1771).  

UK PubMed Central (United Kingdom)

Extensive connective tissue lysis is a common outcome of haplosporidian infection. Although such infections in marine invertebrates are well documented, they are relatively rarely observed in freshwater invertebrates. Herein, we report a field study using a comprehensive series of methodologies (histology, dissection, electron microscopy, gene sequence analysis, and molecular phylogenetics) to investigate the morphology, taxonomy, systematics, geographical distribution, pathogenicity, and seasonal and annual prevalence of a haplosporidian observed in zebra mussels, Dreissena polymorpha. Based on its genetic sequence, morphology, and host, we describe Haplosporidium raabei n. sp. from D. polymorpha - the first haplosporidian species from a freshwater bivalve. Haplosporidium raabei is rare as we observed it in histological sections in only 0·7% of the zebra mussels collected from 43 water bodies across 11 European countries and in none that were collected from 10 water bodies in the United States. In contrast to its low prevalences, disease intensities were quite high with 79·5% of infections advanced to sporogenesis.

Molloy DP; Giambérini L; Stokes NA; Burreson EM; Ovcharenko MA

2012-04-01

 
 
 
 
281

Accumulation of a low pathogenic avian influenza virus in zebra mussels (Dreissena polymorpha).  

UK PubMed Central (United Kingdom)

In order to investigate the potential role of mussels as a vector of influenza A viruses, we exposed zebra mussels (Dreissena polymorpha) to natural lake water containing a low pathogenic H5N1 avian influenza virus. Mussels were kept in water containing virus for 48 hr, then transferred into fresh water for another 14 days. Virus detection in mussels and water samples was performed by quantitative real-time reverse transcriptase-PCR (qRRT-PCR) and egg culture methods. Virus uptake was detected in all of the mussel groups that were exposed to virus. Even after 14 days in fresh water, virus could still be detected in shellfish material by both qRRT-PCR and egg culture methods. The present study demonstrates that zebra mussels are capable of accumulating influenza A viruses from the surrounding water and that these viruses remain in the mussels over an extended period of time.

Stumpf P; Failing K; Papp T; Nazir J; Böhm R; Marschang RE

2010-12-01

282

Chemical defense in the zebra swallowtail butterfly, Eurytides marcellus, involving annonaceous acetogenins.  

Science.gov (United States)

Few herbivores feed on the foliage of the North American paw paw tree, Asimina triloba; notable exceptions are the larvae of the zebra swallowtail butterfly, Eurytides marcellus. Toxic annonaceous acetogenins, produced by A. triloba, are responsible for the relative unpalatability of the leaves. Acetogenins found in A. triloba extracts are potent pesticidal and antineoplastic agents and have emetic activity in vertebrates. In this study, partitioned aqueous MeOH fractions of the bioactive CH2Cl2 extracts, of freeze-dried and pulverized larvae, and of mature butterflies revealed acetogenin content through the use of HPLC coupled to tandem MS (LC-MS/MS). This sensitive technique provides an uncomplicated method for the detection of trace compounds and, in this instance, has confirmed tissue presence of acetogenins that serve a probable role as chemical defense agents against bird predation in zebra swallowtail larvae and adults. PMID:9917274

Martin, J M; Madigosky, S R; Gu, Z M; Zhou, D; Wu, J; McLaughlin, J L

1999-01-01

283

Sobre la validez taxonómica de Epithemia Zebra var. Elongata (Epithemiaceae, Bacillariophyceae)  

Directory of Open Access Journals (Sweden)

Full Text Available Gorritti, G., Sala, S. E. & Guerrero, J. M. 2000. Sobre la validez taxonómica de Epithemiazebra var. elongata (Epithemiaceae, Bacillariophyceae). Darwiniana 38(3-4): 285-289.Se revisaron materiales de Epithemia zebra var. elongata Grunow ex Frenguelli para establecer lavalidez de este taxón. Se estudiaron con microscopio óptico y electrónico de barrido, ejemplares de lacolección Frenguelli y otros recientemente coleccionados en Tierra del Fuego . El análisis de la variaciónpoblacional de los caracteres morfológicos y morfométricos, y la comparación con los taxones afines:Epithemia adnata (Kützing) Brébisson y E. adnata var. minor (Peragallo & Héribaud) Patrick, demostróque no existen diferencias entre ellos por lo que E. zebra var. elongata debe ser considerada sinónimo deE. adnata

Gabriela Gorritti; Silvia E. Sala; José M. Guerrero

2000-01-01

284

A model of so-called "Zebra" emissions in solar flare radio burst continua  

Science.gov (United States)

A simple mechanism for the generation of electromagnetic "Zebra" pattern emissions is proposed. "Zebra" bursts are regularly spaced narrow-band radio emissions on the otherwise broadband radio continuum emitted by the active solar corona. The mechanism is based on the generation of an ion-ring distribution in a magnetic mirror geometry in the presence of a properly directed field-aligned electric potential field. Such ion-rings or ion-conics are well known from magnetospheric observations. Under coronal conditions they may become weakly relativistic. In this case the ion-cyclotron maser generates a number of electromagnetic ion-cyclotron harmonics which modulate the electron maser emission. The mechanism is capable of switching the emission on and off or amplifying it quasi-periodically which is a main feature of the observations.

Treumann, R. A.; Nakamura, R.; Baumjohann, W.

2011-09-01

285

Lake Erie and Lake Michigan zebra mussel settlement monitoring and implications for chlorination treatment  

International Nuclear Information System (INIS)

[en] This paper reports on the 1991 zebra mussel veliger settlement monitoring program undertaken to record and evaluate zebra mussel veliger settlement in Lake Erie and Lake Michigan. Studies by Dr. Gerald Mackie of Canada in 1990 indicated veliger settlement may be occurring primarily during short time periods every season corresponding with warmer water temperatures. Veliger settlement monitoring was performed using a plexiglass sampler apparatus. The samplers were simple in design and consisted of a 20-inch-square plexiglass base panel with thirty-six 1 inch x 3 inch clear plexiglass microscope slides attached. The results of the monitoring program indicate the existence of preferential settlement periods for veligers correlating with sustained lake water temperatures above 70 degrees F. Veliger settlement concentrations in the south basin of Lake Michigan appear to be similar to those in western Lake Erie

1992-01-01

286

A model of so-called "Zebra" emissions in solar flare radio burst continua  

Directory of Open Access Journals (Sweden)

Full Text Available A simple mechanism for the generation of electromagnetic "Zebra" pattern emissions is proposed. "Zebra" bursts are regularly spaced narrow-band radio emissions on the otherwise broadband radio continuum emitted by the active solar corona. The mechanism is based on the generation of an ion-ring distribution in a magnetic mirror geometry in the presence of a properly directed field-aligned electric potential field. Such ion-rings or ion-conics are well known from magnetospheric observations. Under coronal conditions they may become weakly relativistic. In this case the ion-cyclotron maser generates a number of electromagnetic ion-cyclotron harmonics which modulate the electron maser emission. The mechanism is capable of switching the emission on and off or amplifying it quasi-periodically which is a main feature of the observations.

R. A. Treumann; R. Nakamura; W. Baumjohann

2011-01-01

287

Injury induced expression of glial androgen receptor in the zebra finch brain.  

UK PubMed Central (United Kingdom)

Astrogliosis occurs following injury to the zebra finch brain. To date, only estrogen synthase (aromatase) has been identified in injury-induced astrocytes. The expression of other steroidogenic enzymes or their receptors remains unknown in the avian brain. However, in mammals an upregulation of androgen receptors has been identified in glial cells. The aim of this study was to determine if the androgen receptor is upregulated following injury in adult zebra finches. Finches were given a single penetrating injury and brain tissue was collected 24 or 72 hours later. Expression of androgen receptor was examined using immunohistochemistry and quantified using qPCR analysis. Androgen receptors were localized to astrocytes versus neurons, further solidifying the role for astrocytes in neural recovery.

Duncan KA; Vartosis D; Moon J; Zee I

2013-07-01

288

Maximized song learning of juvenile male zebra finches following BDNF expression in the HVC.  

UK PubMed Central (United Kingdom)

During song learning, vocal patterns are matched to an auditory memory acquired from a tutor, a process involving sensorimotor feedback. Song sensorimotor learning and song production of birds is controlled by a set of interconnected brain nuclei, the song control system. In male zebra finches, the beginning of the sensorimotor phase of song learning parallels an increase of the brain-derived neurotrophic factor (BDNF) in just one part of the song control system, the forebrain nucleus HVC. We report here that transient BDNF-mRNA upregulation in the HVC results in a maximized copying of song syllables. Each treated bird shows motor learning to an extent similar to that of the selected best learners among untreated zebra finches. Because this result was not found following BDNF overexpression in the target areas of HVC within the song system, HVC-anchored mechanisms are limiting sensorimotor vocal learning.

Dittrich F; Ter Maat A; Jansen RF; Pieneman A; Hertel M; Frankl-Vilches C; Gahr M

2013-08-01

289

Quasi-periodic wiggles of microwave zebra structures in a solar flare  

CERN Multimedia

Quasi-periodic wiggles of microwave zebra pattern structures with period range from about 0.5 s to 1.5 s are found in a X-class solar flare on 2006 December 13 at the 2.6-3.8 GHz with the Chinese Solar Broadband Radio Spectrometer (SBRS/Huairou). Periodogram and correlation analysis show that the wiggles have two-three significant periodicities and almost in phase between stripes at different frequency. The Alfven speed estimated from the zebra pattern structures is about 700 Km/s. We obtain the spatial size of the waveguiding plasma structure to be about 1 Mm with the detected period of about 1 s. It suggests the ZP wiggles can be associated with the fast mag- netoacoustic oscillations in the flaring active region. The lack of a significant phase shift between wiggles of different stripes suggests that the ZP wiggles are caused by a standing sausage oscillation.

Yu, Sijie; Selzer, L A; Tan, Baolin; Yan, Yihua

2013-01-01

290

Altered patterns of filopodia production in CHO cells heterologously expressing zebra finch CB(1) cannabinoid receptors.  

Science.gov (United States)

Recent findings indicate that cannabinoid-altered vocal development involves elevated densities of dendritic spines in a subset of brain regions involved in zebra finch song learning and production suggesting that cannabinoid receptor activation may regulate cell structure. Here we report that activation of zebra finch CB 1 receptors (zfCB 1, delivered by a lentivector to CHO cells) produces dose-dependent biphasic effects on the mean length of filopodia expressed: Low agonist concentrations (3 nM WIN55212-2) increase lengths while higher concentrations reduce them. In contrast, treatment of zfCB 1-expressing cells with the antagonist/inverse agonist SR141716A causes increases in both mean filopodia length and number at 30 and 100 nM. These results demonstrate that CB 1 receptor activation can differentially influence filiopodia elongation depending on dose, and demonstrate that manipulation of cannabinoid receptor activity is capable of modulating cell morphology. PMID:22568949

Soderstrom, Ken; Zhang, Yuguo; Wilson, Ashley R

2012-03-01

291

Altered patterns of filopodia production in CHO cells heterologously expressing zebra finch CB(1) cannabinoid receptors.  

UK PubMed Central (United Kingdom)

Recent findings indicate that cannabinoid-altered vocal development involves elevated densities of dendritic spines in a subset of brain regions involved in zebra finch song learning and production suggesting that cannabinoid receptor activation may regulate cell structure. Here we report that activation of zebra finch CB 1 receptors (zfCB 1, delivered by a lentivector to CHO cells) produces dose-dependent biphasic effects on the mean length of filopodia expressed: Low agonist concentrations (3 nM WIN55212-2) increase lengths while higher concentrations reduce them. In contrast, treatment of zfCB 1-expressing cells with the antagonist/inverse agonist SR141716A causes increases in both mean filopodia length and number at 30 and 100 nM. These results demonstrate that CB 1 receptor activation can differentially influence filiopodia elongation depending on dose, and demonstrate that manipulation of cannabinoid receptor activity is capable of modulating cell morphology.

Soderstrom K; Zhang Y; Wilson AR

2012-03-01

292

DDT contamination in Lake Maggiore (N. Italy) and effects on zebra mussel spawning.  

UK PubMed Central (United Kingdom)

Zebra mussel (Dreissena polymorpha) is commonly used as contaminant bioindicator in Europe and North America. We used the zebra mussel to follow DDT pollution trends from 1996 to 1997 in Pallanza bay, Lake Maggiore, near the inlet of the River Toce, after a DDT-manufacturing plant discharging residues into a tributary of the River Toce had closed down. DDT contamination fell off sharply outside the bay, but tissue concentrations of the parent compound and residues remained high in molluscs sampled within the bay a year later. Molluscs collected in Pallanza bay in June 1997 released gametes earlier than those sampled at a nearby reference station. Histological studies showed that a significant percentage of these specimens showed marked oocyte degeneration suggesting that DDTs have endocrine-disrupting effects in this species.

Binelli A; Bacchetta R; Vailati G; Galassi S; Provini A

2001-11-01

293

Detection of micronuclei in haemocytes of zebra mussel and great ramshorn snail exposed to pentachlorophenol.  

UK PubMed Central (United Kingdom)

The frequency of micronuclei (MN) induced by pentachlorophenol (PCP) in haemocytes of zebra mussel, Dreissena polymorpha Pall. and great ramshorn snail, Planorbarius corneus L. was determined over a 14 days of exposure (sampling after 4, 7 and 14 days) under laboratory conditions. PCP doses for zebra mussel ranged from 10 to 150 microg/l, and for ramshorn snail from 10 to 450 microg/l. Micronuclei were detected after bisbenzimide fluorescent staining. Positive responses were observed in both species. The mean MN frequencies in treated mussels ranged between 0.69 and 7.50 per thousand, and between 2.07 and 13.80 per thousand in treated snails. The spontaneous MN levels in mussels averaged from 0.5 to 2.75 per thousand, and in snails from 1.56 to 2.00 per thousand. Our results suggest that haemolymph of both species represent an appropriate test tissue in environmental genotoxicity assessment.

Pavlica M; Klobucar GI; Vetma N; Erben R; Papes D

2000-02-01

294

Amino Acid Substitutions Reveal Distinct Functions of Serine 186 of the ZEBRA Protein in Activation of Early Lytic Cycle Genes and Synergy with the Epstein-Barr Virus R Transactivator  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The ZEBRA protein mediates the switch between the latent and lytic life cycles of Epstein-Barr virus. Z(S186A), a point mutant in ZEBRA’s basic domain in which serine 186 is changed to alanine, is unable to induce expression of lytic cycle mRNAs or proteins from the latent EBV genome even though it ...

Francis, Amy; Ragoczy, Tobias; Gradoville, Lyn; Heston, Lee; El-Guindy, Ayman; Endo, Yoshimi; Miller, George

295

Bioaccumulation and effects of perfluorinated compounds (PFCs) in zebra mussels (Dreissena polymorpha).  

UK PubMed Central (United Kingdom)

Perfluorinated chemicals (PFCs) have been used for many years in numerous industrial products and are known to accumulate in organisms. A recent survey showed that tissue levels of PFCs in aquatic organisms varied among compounds and species being undetected in freshwater zebra mussels Dreissena polymorpha. Here we studied the bioaccumulation kinetics and effects of two major PFCs, perfluorooctane sulfonic acid compound (PFOS) and perfluorooctanoic acid (PFOA), in multixenobiotic transporter activity (MXR) and filtration and oxygen consumption rates in zebra mussel exposed to a range of concentrations of a PCF mixture (1-1,000 ?g/L) during 10 days. Results indicate a low potential of the studied PFCs to bioaccumulate in zebra mussel tissues. PFCs altered mussel MXR transporter activity being inhibited at day 1 but not at day 10. Bioaccumulation kinetics of PFCs were inversely related with MXR transporter activity above 9 ng/g wet weight and unrelated at tissue concentration lower than 2 ng/g wet weight suggesting that at high tissue concentrations, these type of compounds may be effluxed out by MXR transporters and as a result have a low potential to be bioaccumulated in zebra mussels. Oxygen consumption rates but not filtering rates were increased in all exposure levels and periods indicating that at environmental relevant concentrations of 1 ?g/L, the studied PFCs enhanced oxidative metabolism of mussels. Overall, the results obtained in this study confirm previous findings in the field indicating that an important fraction of PFC accumulated in mussel tissues is eliminated actively by MXR transporters or other processes that are metabolically costly.

Fernández-Sanjuan M; Faria M; Lacorte S; Barata C

2013-04-01

296

Baltimore City adopts a proactive approach to zebra mussel control using potassium permanganate  

Energy Technology Data Exchange (ETDEWEB)

In 1992, The Baltimore City Department of Public Works initiated aggressive, proactive measures to guard against the infiltration of zebra mussels into local reservoirs and river supplies, which provide raw and finished water to more than 1.6 million people in the City and five neighboring counties. After months of detailed study and planning, Baltimore City appropriated $3.66 million in July 1994 to construct zebra mussel control facilities. Three of the structures will house units that inject controlled doses of potassium permanganate into water intake pipes located in the Liberty and Loch Raven reservoirs and the Susquehanna River. In the event the zebra mussel makes its way into Maryland waters, the chemical would create a hostile environment for the mollusk preventing the mussels` colonization in the more than 20 miles of water tunnels that lead to area filtration plants. Though chlorine is preferred chemical for control in other municipalities, studies indicate that chlorine by-products, known as trihalomethanes, would near or exceed future Environmental Protection Agency standards (a maximum of 80 parts per billion) for drinking water. Consequently, it was decided to use potassium permanganate as the primary control chemical, with chlorine as an emergency backup. In addition, the City plans to construct a thermal control system as the Prettyboy reservoir intake to control the mussel threat without harming the thriving trout population found downstream from the dam. Baltimore City officials have also spearheaded a program using innovative posters to heighten public awareness to the potential harm that can result from the careless transportation of zebra mussels from infested to uninhabited waters. The City`s actions have helped ensure protected waters for Maryland residents and reduced the need for additional public spending to defend against the stealthy intruder.

Balog, G.G. [Baltimore City of Public Works, MD (United States); Neimery, T.F. [KCI Technologies, Inc., Hunt Valley, MD (United States); Davis, L.S. [Baltimore City Bureau of Water and Waster Water, MD (United States)] [and others

1995-06-01

297

Effects of shell morphology on mechanics of zebra and quagga mussel locomotion.  

UK PubMed Central (United Kingdom)

Although zebra mussels (Dreissena polymorpha) initially colonized shallow habitats within the North American Great Lakes, quagga mussels (Dreissena bugensis) are becoming dominant in both shallow- and deep-water habitats. Shell morphology differs among zebra, shallow quagga and deep quagga mussels but functional consequences of such differences are unknown. We examined effects of shell morphology on locomotion for the three morphotypes on hard (typical of shallow habitats) and soft (characteristic of deep habitats) sedimentary substrates. We quantified morphology using the polar moment of inertia, a parameter used in calculating kinetic energy that describes shell area distribution and resistance to rotation. We quantified mussel locomotion by determining the ratio of rotational (K(rot)) to translational kinetic energy (K(trans)). On hard substrate, K(rot):K(trans) of deep quagga mussels was fourfold greater than for the other morphotypes, indicating greater energy expenditure in rotation relative to translation. On soft substrate, K(rot):K(trans) of deep quagga mussels was approximately one-third of that on hard substrate, indicating lower energy expenditure in rotation on soft substrate. Overall, our study demonstrates that shell morphology correlates with differences in locomotion (i.e. K(rot):K(trans)) among morphotypes. Although deep quagga mussels were similar to zebra and shallow quagga mussels in terms of energy expenditure on sedimentary substrate, their morphology was energetically maladaptive for linear movement on hard substrate. As quagga mussels can possess two distinct morphotypes (i.e. shallow and deep morphs), they might more effectively utilize a broader range of substrates than zebra mussels, potentially enhancing their ability to colonize a wider range of habitats.

Peyer SM; Hermanson JC; Lee CE

2011-07-01

298

Use of zebra mussel (dreissena polymorpha) to assess trace metals in river water  

International Nuclear Information System (INIS)

[en] Ebro river (Spain) has been fairly contaminated by industrial effluents: The toxicity level of the river due to heavy metals has been monitored by analyzing zebra mussels (Dreissena Polymorpha) samples as bioindicator. To access the level of toxicity ten metals (AI, Cd, Cr, Cu, Fe, Ni, Pb, Se, Sn and Zn) were determined by Voltamperometry. The conditions of determination were optimized for each metal prior to determination. Aqueous solutions of metals concerned were used as standards in detenpinations. (author)

2007-01-01

299

Experimental assessment of the imaging quality of the low energy gamma-ray telescope ZEBRA  

International Nuclear Information System (INIS)

[en] One gamma-ray detection plane of the ZEBRA telescope, consisting of nine position sensitive scintillation crystal bars designed to operate over the spectral range 0.2 to 10 MeV, has been constructed in the laboratory. A series of experimental images has been generated using a scaled down flight pattern mask in conjunction with a diverging gamma-ray beam. Point and extended sources have been imaged in order to assess quantitatively the performance of the system

1985-01-01

300

Tests of some FD 5 activation cross-sections by Zebra irradiations  

International Nuclear Information System (INIS)

[en] Reactions likely to contribute to the activation of the primary circuit of a fast power reactor have been measured by irradiating small samples of sodium, chromium, manganese, iron, cobalt, nickel, molybdenum and tantalum in the core and axial breeder of Zebra Assembly 14. Results expressed relative to fission rates in Pu-239 and U-238 are compared with predictions using UK FD5 cross-sections

1977-12-08

 
 
 
 
301

TLD gamma-ray energy deposition measurements in the zero energy fast reactor ZEBRA  

International Nuclear Information System (INIS)

[en] A recent study of gamma-ray energy deposition was carried out in the Zebra reactor at AEE Winfrith during a collaborative programme between the UKAEA and PNC of Japan. The programme was given the title MOZART. This paper describes the TLD experiments in the MOZART MZB assembly and discusses the technique and various corrections necessary to relate the measured quantity to the calculated energy deposition

1975-09-26

302

Summary of Ontario Hydro's 1990-91 zebra mussel research program  

International Nuclear Information System (INIS)

[en] Ontario Hydro is the principal supplier of electricity to the Province of Ontario. It serves 3.6 million customers, with an inservice capacity of 28,200 MW. Ontario Hydro has seven fossil, five nuclear, and four hydraulic stations in the Great Lakes Basin and surrounding watershed. In addition, there are another 60 inland hydraulic stations and numerous dams. As the largest single user of raw water from the Great Lakes Basin, Ontario Hydro recognized the need to control zebra mussels early in 1989. At that time, very little was known in North America about the zebra mussel life cycle and potential impact. European utilities were consulted, but as we now know, zebra mussels are not perceived to be a problem in Europe at this time. To satisfy the immediate need for control, chlorination was identified as the most effective interim measure to prevent the fouling of systems which draw water from the aquatic environment. Due to the current regulatory environment, this solution is considered short term and Ontario Hydro was compelled to initiate a comprehensive research effort aimed at providing alternative methods of control. Most of the research effort during 1990, was methods of control. Most of the research effort during 1990, was directed towards this goal. Many alternative control measures, both chemical and nonchemical were considered. Also considered were the potential effects of the control measures and zebra mussels on station operations. A multidisciplinary team involving aquatic biologists, chemists, corrosion specialists, and civil and mechanical engineers from the various departments of Ontario Hydro was asked to address the problem. Some of the research also involved collaborative studies with universities, US utilities, American Water Works Association, and Canadian industries. Following is a summary of the research effort in 1990, and a preview of the research underway in 1991

1992-01-01

303

Noninvasive diffusive optical imaging of the auditory response to birdsong in the zebra finch.  

UK PubMed Central (United Kingdom)

Songbirds communicate by learned vocalizations with concomitant changes in neurophysiological and genomic activities in discrete parts of the brain. Here, we tested a novel implementation of diffusive optical imaging (also known as diffuse optical imaging, DOI) for monitoring brain physiology associated with vocal signal perception. DOI noninvasively measures brain activity using red and near-infrared light delivered through optic fibers (optodes) resting on the scalp. DOI does not harm subjects, so it raises the possibility of repeatedly measuring brain activity and the effects of accumulated experience in the same subject over an entire life span, all while leaving tissue intact for further study. We developed a custom-made apparatus for interfacing optodes to the zebra finch (Taeniopygia guttata) head using 3D modeling software and rapid prototyping technology, and applied it to record responses to presentations of birdsong in isoflurane-anesthetized zebra finches. We discovered a subtle but significant difference between the hemoglobin spectra of zebra finches and mammals which has a major impact in how hemodynamic responses are interpreted in the zebra finch. Our measured responses to birdsong playback were robust, highly repeatable, and readily observed in single trials. Responses were complex in shape and closely paralleled responses described in mammals. They were localized to the caudal medial portion of the brain, consistent with response localization from prior gene expression, electrophysiological, and functional magnetic resonance imaging studies. These results define an approach for collecting neurophysiological data from songbirds that should be applicable to diverse species and adaptable for studies in awake behaving animals.

Lee JV; Maclin EL; Low KA; Gratton G; Fabiani M; Clayton DF

2013-03-01

304

Oscillating magnetic field disrupts magnetic orientation in Zebra finches, Taeniopygia guttata.  

UK PubMed Central (United Kingdom)

BACKGROUND: Zebra finches can be trained to use the geomagnetic field as a directional cue for short distance orientation. The physical mechanisms underlying the primary processes of magnetoreception are, however, largely unknown. Two hypotheses of how birds perceive magnetic information are mainly discussed, one dealing with modulation of radical pair processes in retinal structures, the other assuming that iron deposits in the upper beak of the birds are involved. Oscillating magnetic fields in the MHz range disturb radical pair mechanisms but do not affect magnetic particles. Thus, application of such oscillating fields in behavioral experiments can be used as a diagnostic tool to decide between the two alternatives. METHODS: In a setup that eliminates all directional cues except the geomagnetic field zebra finches were trained to search for food in the magnetic north/south axis. The birds were then tested for orientation performance in two magnetic conditions. In condition 1 the horizontal component of the geomagnetic field was shifted by 90 degrees using a helmholtz coil. In condition 2 a high frequently oscillating field (1.156 MHz) was applied in addition to the shifted field. Another group of birds was trained to solve the orientation task, but with visual landmarks as directional cue. The birds were then tested for their orientation performance in the same magnetic conditions as applied for the first experiment. RESULTS: The zebra finches could be trained successfully to orient in the geomagnetic field for food search in the north/south axis. They were also well oriented in test condition 1, with the magnetic field shifted horizontally by 90 degrees. In contrast, when the oscillating field was added, the directional choices during food search were randomly distributed. Birds that were trained to visually guided orientation showed no difference of orientation performance in the two magnetic conditions. CONCLUSION: The results indicate that zebra finches use a receptor that bases on radical pair processes for sensing the direction of the earth magnetic field in this short distance orientation behavior.

Keary N; Ruploh T; Voss J; Thalau P; Wiltschko R; Wiltschko W; Bischof HJ

2009-01-01

305

Behavioural changes of zebra mussel Dreissena polymorpha (Bivalvia) induced by Ponto-Caspian gammarids  

UK PubMed Central (United Kingdom)

Colonies of an invasive Ponto-Caspian zebra mussel constitute suitable habitats for many invertebrate organisms, including Ponto-Caspian gammarids that are now spreading throughout Europe. There is, however, little known of the impact of these gammarids on their mussel hosts which they live amongst. We studied the behaviour of zebra mussels in the presence of three gammarid species that differed in their origin and degree of association with Dreissena habitats. In the presence of the Ponto-Caspian invader Dikerogammarus villosus that was commonly observed in mussel habitats, mussels responded by increasing their attachment strength and reducing upward movement. The responses to the Ponto-Caspian Pontogammarus robustoides, a species that showed no preferences for mussel habitats, were weaker and limited to the increase of attachment strength. There were no behavioural changes in mussels exposed to the native Gammarus fossarum. As mussels only responded to gammarids moving freely among their shells and not to those kept behind a mesh barrier, the most likely factor causing these changes was mechanical irritation of their soft parts by amphipod appendages. This hypothesis was further confirmed in an additional experiment with a South-American catfish Corydoras paleatus used as another potential source of mechanical irritation. The responses of zebra mussels to gammarids were similar to their anti-predator defences shown earlier in the presence of molluscivorous roach. Thus, it appears likely that Ponto Caspian gammarids within mussel colonies have the capacity to compromise the normal functioning of bivalves through inducing their defensive responses.

Kobak J; Pozna?ska M; Kakareko T

2012-09-01

306

Assimilation efficiency of organic contaminants from algae by the zebra mussel, Dreissena polymorpha  

Energy Technology Data Exchange (ETDEWEB)

A high percent of hydrophobic contaminants in the Great Lakes are particulate bound. Due to large populations and its high filtering capacity, the zebra mussel, Dreissena polymorpha, has the potential to re-direct contaminants from the water column by removal of contaminated particles, including algae. Throughout a season, zebra mussels feed on a variety of algal species. To determine if there are algal species differences in assimilation efficiency of contaminants, the percent assimilation efficiency (%AE) of three PCB congeners and DDE from three algae species were investigated using pulse-chase methodology. Results suggest no species difference in %AE for hexachlorobiphenyl (HCBP) from the algae Chlorella vulgaris and Chlamydomonas rheinhardtii. The mean %AE of HCBP from C. vulgaris was 60.9 (SE = {+-} 4.1), as compared to 68.6 (SE = {+-} 2.9) from C. rheinhardtii. Results from additional compounds and algal species will be discussed. The results of this study will allow them to refine the mechanism of contaminant uptake in aquatic filter feeders and assess the effect of zebra mussels on contaminant cycling in the Great lakes.

Goldenstein, T.A.; Bruner, K.A.; Fisher, S.W. [Ohio State Univ., Columbus, OH (United States). Dept. of Entomology; Landrum, P.F. [NOAA/Great Lakes Environmental Research Lab., Ann Arbor, MI (United States)

1995-12-31

307

Genetic and phenoptypic differentiation of zebra mussel populations colonizing Spanish river basins.  

UK PubMed Central (United Kingdom)

Zebra mussel populations in Ebro and Mijares Rivers (northern Spain) were analyzed to study the mechanisms by which this aquatic species deals with pollution. Variability analyses of mitochondrial cytochrome oxidase I gene and of one nuclear microsatellite were performed for ten populations from the Ebro River and one from the Mijares River. Comparison of these results with those from five additional European populations indicated that the Spanish populations constitute a homogeneous gene pool. Transcriptome analyses of gill samples from a subset of the Spanish populations showed changes on expression levels that correlated with variations in general fitness and loads of heavy metals. The less polluted upstream Ebro populations showed overexpression of mitochondrial and cell proliferation-related genes compared to the more polluted, downstream Ebro populations. Our data indicate that heavy metals were the main factors explaining these transcriptomic patterns, and that zebra mussel is resilient to pollutants (like mercury and organochlorine compounds) proved to be extremely toxic to vertebrates. We propose that zebra mussel populations sharing a common gene pool may acclimate to different levels and forms of pollution through modulations in their transcriptomic profile, although direct selection on genes showing differential expression patterns cannot be ruled out.

Navarro A; Sánchez-Fontenla J; Cordero D; Faria M; Peña JB; Saavedra C; Blázquez M; Ruíz O; Ureña R; Torreblanca A; Barata C; Piña B

2013-07-01

308

The zebra finch paradox: song is little changed, but number of neurons doubles.  

UK PubMed Central (United Kingdom)

New neurons are added to the high vocal center (HVC) of adult males in seasonally breeding songbirds such as the canary (Serinus canaria) that learns new songs in adulthood, and the song sparrow (Melospiza melodia) that does not. In both cases, the new neurons numerically replace others that have died, resulting in a seasonal fluctuation in HVC volume and neuron number. Peaks in neuronal replacement in both species occur in the fall when breeding is over and song is variable. New neurons are added, too, to the HVC of zebra finches (Taeniopygia guttata) that do not learn new songs in adulthood and whose song remains stereotyped throughout the year. Here, we show that, in contrast to the observations in seasonal songbirds, neurons added to the zebra finch HVC are not part of a replacement process. Rather, they lead to a doubling in the number of neurons that project from HVC to the robust nucleus of the arcopallium (RA). As this happens, HVC volume remains constant and the packing density of its neurons increases. The HVC-RA neurons are part of a descending pathway that carries the pattern of learned song; some HVC-RA neurons are also responsive to song playback. The addition of HVC-RA neurons happens in zebra finches housed singly, but becomes more acute if the birds are housed communally. We speculate that new neurons added to the adult HVC may help with the production or perception of learned song, or both.

Walton C; Pariser E; Nottebohm F

2012-01-01

309

Zebra mussels (Dreissena polymorpha) as indicators of freshwater contamination with lindane  

International Nuclear Information System (INIS)

[en] Zebra mussels are common freshwater mollusks in many European lakes and rivers. Their abundance, wide distribution, and filtering activity make them good candidates to evaluate the contamination of fresh waters with environmental contaminants. The purpose of this work was to determine the kinetics of lindane in zebra mussels and compare laboratory results with in situ measurements. Exposure was conducted in small tanks, under controlled experimental conditions. Our results indicated that mussels accumulated lindane with a bioconcentration factor around 10. They generally reached equilibrium within 4 days. Elimination was rapid but biphasic and the terminal elimination half-life was long (>168 h). Age of the mussels and temperature also affected the kinetics of lindane in mussels. In the Lake of eneva, zebra mussels were sampled and showed that mussels accumulated it to significant values (up to 900 ng/g fresh weight) depending on the site and period of sampling. The in situ results, together with the laboratory exposures, showed that freshwater mussels could be used to monitor point sources of pollutants such as lindane over short periods of time (

2002-01-01

310

Great Lakes clams find refuge from zebra mussels in restored, lake-connected marsh (Ohio)  

Science.gov (United States)

Since the early 1990s, more than 95 percent of the freshwater clams once found in Lake Erie have died due to the exotic zebara mussel (Dreissena polymorpha). Zebra mussels attach themselves to native clams in large numbers, impeding the ability of the clams to eat and burrow. However, in 1996, we discovered a population of native clams in Metzger Marsh in western Lake Erie (about 50 miles [80 km] east of Toledo) that were thriving despite the longtime presence of zebra mussel in surrounding waters. At that time, Metzger Marsh was undergoing extensive restoration, including construction of a dike to replace the eroded barrier beach and of a water-control structure to maintain hydrologic connections with the lake (Wilcox and Whillans 1999). The restoration plan called for a drawdown of water levels to promote plant growth from the seedbank -- a process that would also destroy most of the clam population. State and federal resource managers recommended removing as many clams as possible to a site that was isolated from zebra mussels, and then returning them to the marsh after it was restored. We removed about 7,000 native clams in 1996 and moved them back to Metzger Marsh in 1999.

Nichols, S. Jerrine; Wilcox, Douglas A.

2004-01-01

311

Genetic and phenoptypic differentiation of zebra mussel populations colonizing Spanish river basins.  

Science.gov (United States)

Zebra mussel populations in Ebro and Mijares Rivers (northern Spain) were analyzed to study the mechanisms by which this aquatic species deals with pollution. Variability analyses of mitochondrial cytochrome oxidase I gene and of one nuclear microsatellite were performed for ten populations from the Ebro River and one from the Mijares River. Comparison of these results with those from five additional European populations indicated that the Spanish populations constitute a homogeneous gene pool. Transcriptome analyses of gill samples from a subset of the Spanish populations showed changes on expression levels that correlated with variations in general fitness and loads of heavy metals. The less polluted upstream Ebro populations showed overexpression of mitochondrial and cell proliferation-related genes compared to the more polluted, downstream Ebro populations. Our data indicate that heavy metals were the main factors explaining these transcriptomic patterns, and that zebra mussel is resilient to pollutants (like mercury and organochlorine compounds) proved to be extremely toxic to vertebrates. We propose that zebra mussel populations sharing a common gene pool may acclimate to different levels and forms of pollution through modulations in their transcriptomic profile, although direct selection on genes showing differential expression patterns cannot be ruled out. PMID:23681738

Navarro, Anna; Sánchez-Fontenla, Javier; Cordero, David; Faria, Melisa; Peña, Juan B; Saavedra, Carlos; Blázquez, Mercedes; Ruíz, Olga; Ureña, Rocío; Torreblanca, Amparo; Barata, Carlos; Piña, Benjamin

2013-05-17

312

Zebra mussels (Dreissena polymorpha) as a biomonitoring tool for Sr90 contamination  

International Nuclear Information System (INIS)

[en] Due to their efficient filtration capabilities, zebra mussels (Dreissena polymorpha) are effective biomonitors of a wide range of environmental pollutants. In this study we test the suitability of zebra mussels as bio-monitors of Sr90 contamination around a nuclear power station situated at Gentilly, Quebec along the St. Lawrence River. Based on the latest emission data which indicated negligible contributions of Sr90 to the river, we hypothesize that dreissenids collected at sites upstream (Montreal), at the station and downstream from the station (Donnacona) would show no significant differences in shell concentrations of Sr90. Zebra mussel shell concentrations of Sr90 were in the order of 0.02 pCi/g at Gentilly, 0.04 pCi/g at Montreal and 0.03 pCi/g at Donnacona, all values being below the limit of detection of the analytical method. We also considered the implication of Sr90 contamination to higher trophic levels in the food chain. (Author)

1994-01-01

313

Drivers and Controls of the Zebra Mussel Invasion of the Mississippi-Missouri River System  

Science.gov (United States)

The zebra mussel Dreissena polymorpha has been haunting North American inland waters for the past twenty years. Due to the huge population densities reached by local colonies and the species' unparalleled dispersal ability, the zebra mussel represents a major threat from both an ecological and an economic perspective. We propose a novel ecohydrological model for the invasion of inland waters by this alien species and test it against field data gathered within the Mississippi-Missouri river system in North America. To incorporate both hydrologic controls and anthropogenic drivers of the invasion, the proposed multi-layer network model accounts explicitly for zebra mussel demographic dynamics, hydrologic transport and dispersal due to human activities. We show that hydrologic transport alone is not sufficient to explain the spread of the species at the basin scale. We also quantify the role played by commercial navigation in promoting the initial, selective colonization of the river system and show how recreational boating may have determined the capillary penetration of the species into the water system. The role of post-establishment dispersal mechanisms and the effectiveness of possible prevention measures are also discussed in the context of model sensitivity and robustness to reparameterization.

Casagrandi, R.; Mari, L.; Bertuzzo, E.; Gatto, M.; Levin, S. A.; Rodriguez-Iturbe, I.; Rinaldo, A.

2010-12-01

314

Using Digital Images of the Zebra Finch Song System as a Tool to Teach Organizational Effects of Steroid Hormones: A Free Downloadable Module  

Science.gov (United States)

|Zebra finch song behavior is sexually dimorphic: males sing and females do not. The neural system underlying this behavior is sexually dimorphic, and this sex difference is easy to quantify. During development, the zebra finch song system can be altered by steroid hormones, specifically estradiol, which actually masculinizes it. Because of the…

Grisham, William; Schottler, Natalie A.; Beck McCauley, Lisa M.; Pham, Anh P.; Ruiz, Maureen L.; Fong, Michelle C.; Cui, Xinran

2011-01-01

315

The Origin of a “Zebra” Chromosome in Wheat Suggests Nonhomologous Recombination as a Novel Mechanism for New Chromosome Evolution and Step Changes in Chromosome Number  

Digital Repository Infrastructure Vision for European Research (DRIVER)

An alloplasmic wheat line, TA5536, with the “zebra” chromosome z5A was isolated from an Elymus trachycaulus/Triticum aestivum backcross derivative. This chromosome was named “zebra” because of its striped genomic in situ hybridization pattern. Its origin was traced to nonhomologous chromosome 5A of ...

Zhang, Peng; Li, Wanlong; Friebe, Bernd; Gill, Bikram S.

316

Gene duplication and fragmentation in the zebra finch major histocompatibility complex  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Due to its high polymorphism and importance for disease resistance, the major histocompatibility complex (MHC) has been an important focus of many vertebrate genome projects. Avian MHC organization is of particular interest because the chicken Gallus gallus, the avian species with the best characterized MHC, possesses a highly streamlined minimal essential MHC, which is linked to resistance against specific pathogens. It remains unclear the extent to which this organization describes the situation in other birds and whether it represents a derived or ancestral condition. The sequencing of the zebra finch Taeniopygia guttata genome, in combination with targeted bacterial artificial chromosome (BAC) sequencing, has allowed us to characterize an MHC from a highly divergent and diverse avian lineage, the passerines. Results The zebra finch MHC exhibits a complex structure and history involving gene duplication and fragmentation. The zebra finch MHC includes multiple Class I and Class II genes, some of which appear to be pseudogenes, and spans a much more extensive genomic region than the chicken MHC, as evidenced by the presence of MHC genes on each of seven BACs spanning 739 kb. Cytogenetic (FISH) evidence and the genome assembly itself place core MHC genes on as many as four chromosomes with TAP and Class I genes mapping to different chromosomes. MHC Class II regions are further characterized by high endogenous retroviral content. Lastly, we find strong evidence of selection acting on sites within passerine MHC Class I and Class II genes. Conclusion The zebra finch MHC differs markedly from that of the chicken, the only other bird species with a complete genome sequence. The apparent lack of synteny between TAP and the expressed MHC Class I locus is in fact reminiscent of a pattern seen in some mammalian lineages and may represent convergent evolution. Our analyses of the zebra finch MHC suggest a complex history involving chromosomal fission, gene duplication and translocation in the history of the MHC in birds, and highlight striking differences in MHC structure and organization among avian lineages.

Balakrishnan Christopher N; Ekblom Robert; Völker Martin; Westerdahl Helena; Godinez Ricardo; Kotkiewicz Holly; Burt David W; Graves Tina; Griffin Darren K; Warren Wesley C; Edwards Scott V

2010-01-01

317

Humoral response of captive zebra sharks Stegostoma fasciatum to salivary gland proteins of the leech Branchellion torpedinis.  

UK PubMed Central (United Kingdom)

Parasitism by the marine leech Branchellion torpedinis is known to cause disease and mortality in captive elasmobranchs and is difficult to control when inadvertently introduced into public aquaria. Preliminary characterization of the salivary gland transcriptome of B. torpedinis has identified anticoagulants, proteases, and immunomodulators that may be secreted into host tissues to aid leech feeding. This retrospective study examined antigen-specific serum IgM responses in captive zebra sharks Stegostoma fasciatum to leech salivary gland extract. Antibody response was examined by ELISA and Western blot assays in 20 serum samples from six zebra sharks, with a 5 year history of leech infection, and 18 serum samples from 8 captive bred zebra sharks, with no history of leech exposure. ELISA demonstrated significantly higher serum IgM titers to salivary gland extract in exposed zebra sharks compared to the non-exposed population. No obvious trends in antibody titers were appreciated in exposed zebra sharks over a four-year period. One-dimensional and two-dimensional Western blot assays revealed IgM targeted specific salivary gland proteins within the 40, 55, 70 and 90 kD range. Antigenic proteins identified by liquid chromatography-tandem mass spectrometry and de novo peptide sequencing include a secreted disintegrin, metalloproteinase and thrombospondin motif containing protein (ADAMTS), tubulin, aldehyde dehydrogenase and two unknown proteins. Humoral immune responses to leech salivary gland proteins warrants further investigation as there may be options to exploit immune mechanisms to reduce parasite burdens in aquaria.

Marancik DP; Leary JH; Fast MM; Flajnik MF; Camus AC

2012-10-01

318

Application experience with ADBAC/DGH cationic surfactants for zebra mussel control in a nuclear service water system  

International Nuclear Information System (INIS)

[en] In response to the introduction and rapid growth of the zebra mussel population in the Great Lakes and the issuance of NRC Generic Letter 89-13 (Service Water Problems Affecting Safety-Related Equipment). A midwest nuclear station instituted a zebra mussel monitoring and control program. The nuclear station uses Lake Michigan as a cooling water source for two 1,100 MW Westinghouse 4-loop design, pressurized water reactors (PWR). Two years of monitoring indicated a growth in zebra mussel population from 0.5 organisms/m2 in July 1990 to 100 organisms/m2 by November 1990. This rapid increase indicated an urgent need for viable methods of zebra mussel control to protect the plant's essential service water (ESW) and non-essential service water (NESW) systems. In April 1991, the station formulated a plan that combined increased system inlet temperature with targeted application of a proprietary product containing two cationic surfactants, ADBAC/DGH. Sidestream biomonitoring boxes were seeded with zebra mussels and observed as a measure of the efficacy of the treatment. Where recommended dosages and duration were maintained, 100% control was achieved

1992-01-01

319

Bioassessment of mercury, cadmium, polychlorinated biphenyls, and pesticides in the Upper Mississippi River with zebra mussels (Dreissena polymorpha)  

Energy Technology Data Exchange (ETDEWEB)

Zebra mussels (Dreissena polymorpha) were sampled from artificial substrates deployed from May 30 to October 19, 1995, at 19 locks and dams from Minneapolis, MN, to Muscatine, IA. Analyses of composite tissue samples of zebra mussels revealed accumulation of mercury (Hg), cadmium (Cd), and polychlorinated biphenyls (PCBs) during a 143-d exposure period. Concentrations of total Hg ranged from 2.6 to 6.1 ng/g wet weight and methylmercury (CH{sub 3}Hg) from 1.0 to 3.3 ng/g wet weight. About 50% of the mean total Hg in zebra mussels was CH{sub 3}Hg. Cadmium ranged from 76 to 213 ng/g wet weight. Concentrations of total PCBs in zebra mussels varied longitudinally, but the composition of PCB congeners was similar throughout the river. Chlordane and dieldrin were the only two pesticides detected of the 15 analyzed. Zebra mussels are sentinels of contaminant bioavailability in the Upper Mississippi River and may be an important link in the trophic transfer of contaminants in the river because of their increasing importance in the diets of certain fish and waterfowl.

Cope, W.G.; Bartsch, M.R.; Rada, R.G.; Balogh, S.J.; Rupprecht, J.E.; Young, R.D.; Johnson, D.K.

1999-12-15

320

Analysis of implosion dynamics of nested cylindrical wire arrays of Mo and Al on the Zebra and Cobra generators  

Science.gov (United States)

Results of experiments with nested cylindrical wire arrays of Mo and Al that were performed on the 1.6 MA, 100 ns Zebra generator and the 1.0 MA, 100 ns Cobra generator are presented. Both the Zebra and Cobra experiments had loads with Al tracer wires with different concentrations in linear mass (˜30% Al for Zebra and ˜15% Al for Cobra). The full set of diagnostics produced data that were compared and analyzed, which include PCD, XRD, and bolo signals, laser shadowgraphy and optical streak images, and time-gated/integrated pinhole and spectra images. Implosion dynamics is analyzed with a wire-ablation dynamics model. Non-LTE kinetic modeling was utilized to derive plasma parameters of electron temperature and density and to estimate opacity effects. The advantage of using Mo wires for future study of L-shell radiators from wire arrays is demonstrated.

Weller, M. E.; Yilmaz, M. F.; Safronova, A. S.; Kantsyrev, V. L.; Esaulov, A. A.; Williamson, K. M.; Shrestha, I.; Osborne, G. C.; Ouart, N. D.; Shylaptseva, V.

2009-11-01

 
 
 
 
321

Temporal and spatial variation in Hg accumulation in zebra mussels (Dreissena polymorpha): possible influences of DOC and diet.  

UK PubMed Central (United Kingdom)

Zebra mussels (Dreissena polymorpha) are filter feeders located near the base of the foodweb and these animals are able to utilize a variety of carbon sources that may also vary seasonally. We conducted both a spatial and a temporal study in order to test the hypotheses: (1) dissolved organic carbon (DOC) concentrations influence Hg accumulation in zebra mussels sampled from a series of lakes and (2) seasonal variations in diet influence Hg accumulation. In the spatial study, we found a significant negative relationship between Hg concentrations and DOC concentrations, suggesting an influence of DOC on Hg bioaccumulation. In the temporal study, we used stable isotope ratios of nitrogen (?(15)N) and carbon (?(13)C) as ecological tools to provide a temporally integrated description of the feeding ecology of zebra mussels. Both ?(15)N and ?(13)C varied seasonally in a similar manner: more depleted values occurred in the summer and more enriched values occurred in the fall. Mercury concentrations also varied significantly over the year, with highest concentrations occurring in the summer, followed by a progressive decrease in concentrations into the fall. The C/N ratio of zebra mussels also varied significantly over the year with the lowest values occurring mid-summer and then values increased in the fall and winter, suggesting that there was significant variation in lipid stores. These results indicate that in addition to any effect of seasonal dietary changes, seasonal variation in energy stores also appeared to be related to Hg levels in the zebra mussels. Collectively results from this study suggest that DOC concentrations, seasonal variation in diet and seasonal depletion of energy stores are all important variables to consider when understanding Hg accumulation in zebra mussels.

Kraemer LD; Evans D; Dillon PJ

2013-05-01

322

Genome-wide annotation and analysis of zebra finch microRNA repertoire reveal sex-biased expression  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background MicroRNAs (miRNAs) are small noncoding RNAs that regulate gene expression post-transcriptionally in a wide range of biological processes. The zebra finch (Taeniopygia guttata), an oscine songbird with characteristic learned vocal behavior, provides biologists a unique model system for studying vocal behavior, sexually dimorphic brain development and functions, and comparative genomics. Results We deep sequenced small RNA libraries made from the brain, heart, liver, and muscle tissues of adult male and female zebra finches. By mapping the sequence reads to the zebra finch genome and to known miRNAs in miRBase, we annotated a total of 193 miRNAs. Among them, 29 (15%) are avian specific, including three novel zebra finch specific miRNAs. Many of the miRNAs exhibit sequence heterogeneity including length variations, untemplated terminal nucleotide additions, and internal substitution events occurring at the uridine nucleotide within a GGU motif. We also identified seven Z chromosome-encoded miRNAs. Among them, miR-2954, an avian specific miRNA, is expressed at significantly higher levels in males than in females in all tissues examined. Target prediction analysis reveals that miR-2954, but not other Z-linked miRNAs, preferentially targets Z chromosome-encoded genes, including several genes known to be expressed in a sexually dimorphic manner in the zebra finch brain. Conclusions Our genome-wide systematic analysis of mature sequences, genomic locations, evolutionary sequence conservation, and tissue expression profiles of the zebra finch miRNA repertoire provides a valuable resource to the research community. Our analysis also reveals a miRNA-mediated mechanism that potentially regulates sex-biased gene expression in avian species.

Luo Guan-Zheng; Hafner Markus; Shi Zhimin; Brown Miguel; Feng Gui-Hai; Tuschl Thomas; Wang Xiu-Jie; Li XiaoChing

2012-01-01

323

Analysis of an ankyrin-like region in Epstein Barr Virus encoded (EBV) BZLF-1 (ZEBRA) protein: implications for interactions with NF-?B and p53  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background The carboxyl terminal of Epstein-Barr virus (EBV) ZEBRA protein (also termed BZLF-1 encoded replication protein Zta or ZEBRA) binds to both NF-?B and p53. The authors have previously suggested that this interaction results from an ankyrin-like region of the ZEBRA protein since ankyrin proteins such as I?B interact with NF-?B and p53 proteins. These interactions may play a role in immunopathology and viral carcinogenesis in B lymphocytes as well as other cell types transiently infected by EBV such as T lymphocytes, macrophages and epithelial cells. Methods Randomization of the ZEBRA terminal amino acid sequence followed by statistical analysis suggest that the ZEBRA carboxyl terminus is most closely related to ankyrins of the invertebrate cactus I?B-like protein. This observation is consistent with an ancient origin of ZEBRA resulting from a recombination event between an ankyrin regulatory protein and a fos/jun DNA binding factor. In silico modeling of the partially solved ZEBRA carboxyl terminus structure using PyMOL software demonstrate that the carboxyl terminus region of ZEBRA can form a polymorphic structure termed ZANK (ZEBRA ANKyrin-like region) similar to two adjacent I?B ankyrin domains. Conclusions Viral capture of an ankyrin-like domain provides a mechanism for ZEBRA binding to proteins in the NF-?B and p53 transcription factor families, and also provides support for a process termed "Ping-Pong Evolution" in which DNA viruses such as EBV are formed by exchange of information with the host genome. An amino acid polymorphism in the ZANK region is identified in ZEBRA from tumor cell lines including Akata that could alter binding of Akata ZEBRA to the p53 tumor suppressor and other ankyrin binding protein, and a novel model of antagonistic binding interactions between ZANK and the DNA binding regions of ZEBRA is suggested that may be explored in further biochemical and molecular biological models of viral replication.

Dreyfus David H; Liu Yang; Ghoda Lucy Y; Chang Joseph T

2011-01-01

324

Effects of elevated carbon dioxide concentrations on survivorship in zebra mussels (Dreissena polymorpha) and Asian clams (Corbicula fluminea)  

Energy Technology Data Exchange (ETDEWEB)

In order to determine their tolerance to elevated concentrations of carbon dioxide, Asian clams and zebra mussels were collected. Subsamples of both species were acclimated to 25{degrees}C>14 days and then exposed in water at 25{degrees}C to various concentrations of CO{sub 2} and survivorship recorded. Zebra mussels were allowed to byssally attach prior to testing. Media CO{sub 2} concentrations were maintained by continuous bubbling with appropriate gas mixtures. Gas treatment included: (1) anoxia; (2) hypercapnic anoxia; and (3) hypercapnic normoxia. Deaths were recorded in subsamples of both species every 12-24 h until 100% mortality was achieved. No significant mortality occurred among specimens of either species in air bubbled control media in any experiment. Mortality time of zebra mussels exposed to anoxia under 100% N{sub 2} was 103.7 h and of Asian clams, 349.7 h. Mortality was more rapid among samples of both species exposed to anoxia under 100% CO{sub 2}, mean time to death being 43.6 h for zebra mussels and 46.3 h for Asian clams. There was no difference in the survivorship of samples of either species under atmospheres of either 5% CO{sub 2} and 95% N{sub 2} or 100% N{sub 2}, however, Asian clams survived anoxia under either atmosphere 4 to 5 times longer than did zebra mussels. There was no significant mortality among Asian clam or zebra mussel samples after a 39 day exposure to hypercapnic normoxia. While exposure to hypercapnic normoxia under an atmosphere of 5% CO{sub 2}:19% O{sub 2}:76% N{sub 2} did not induce mortality in zebra mussel samples, it completely suppressed all byssal thread production after 7 days of exposure and induced all sampled individuals to release from their byssal attachments within 10 days of exposure. These results indicate that CO{sub 2} injection may be an easily applied, cost-effective, environmentally acceptable molluscicide for mitigation and control of raw water system macrofouling by Asian clams and zebra mussels.

McMahon, R.F.; Matthews, M.A.; Shaffer, L.R.; Johnson, P.D. [Univ. of Texas, Arlington, TX (United States)

1995-06-01

325

Diversidad malacológica en una comunidad de Arca zebra (Mollusca: Bivalvia)en Chacopata, Estado Sucre, Venezuela  

Directory of Open Access Journals (Sweden)

Full Text Available La diversidad malacológica de una comunidad submareal de Arca zebra se estudió, desde septiembre, 1990 hasta septiembre, 1991, en Chacopata, Estado Sucre, Venezuela. Se identificaron 40 especies (24 de bivalvos y 16 de gasterópodos). Los parámetros de diversidad en número de la comunidad fueron bajos (H` = 2.087 bits /ind., J` = 0.392, Simpson = 0.528) cuando se comparan con otros reportes de áreas tropicales. Los datos del número de individuos por especies con el rango conforman una línea recta ajustada por la serie logaritmica, con un índice de diversidad (a) de 5.66. Las máximas diversidades mensuales se observaron en septiembre, 1990 (1.63 bits/ind.) y julio, 1991 (1.60 bits/ind.), la mínima ocurrió en junio, 1991 (0.52 bits/ind.). De las 40 especies identificadas, la pepitona, Arca zebra fue la especie dominante en número (68.87 %) y en biomasa (72.34 %), seguida por Pinctada imbricata, Modiolus squamosus, Chama macerophyla y Anadara notabilis. Los gasterópodos predadores Phyllonotus pomum, Chicoreus brevifrons y Murex recurvirostris parecen tener relaciones tróficas con la especie dominante. La biomasa promedio total en peso húmedo con la concha (469.20 + 263 g m-2) es alta e indica que A. zebra, la especie dominante de rápido crecimiento, desempeña el papel más importante en la comunidad como un eficiente filtrador, que convierte el alimento planctónico en biomasa disponible, soportando una de las pesquerías más importantes de la región.The diversity of a subtidal epifaunal mollusk community was studied from September, 1990 to September, 1991 in Chacopata, Sucre State, Venezuela. There were 40 species (24 bivalves and 16 gastropods). The diversity indexes (H` = 2.087, J`=0.392, 1/D = 0.528) were low when compared with other tropical zones. Monthly diversity reached its maximum in September, 1990 (1.63 bits/ind.) and July, 1991 (1.60 bits/ind.); minimum diversity occurred in June, 1991 (0.52 bits/ind.). A Log series model applied to species abundance data showed a straight line with a diversity index a of 5.56. Of 40 species identified, the turkeywing Arca zebra was dominant (69 % in number of individuals and 72 % of biomass) followed by Pinctada imbricata, Modiolus squamosus, Chama macerophyla and Anadara notabilis. The predatory snails Phyllonotus pomum, Chicoreus brevifrons and Murex recurvirostris seemed to have trophic relationships with A. zebra. The total mean biomass in wet weight (469.20 + 263g m-2, shell included) was high which indicates that A. zebra, a species with a rapid growth rate, occupies a central role in the assemblage as an efficient filter feeder that converts planktonic food into available biomass, supporting one of the most important fisheries in Venezuela.

Antulio S. Prieto; Lilia J. Ruiz; Natividad García; Miyosky Alvarez

2001-01-01

326

Diversidad malacológica en una comunidad de Arca zebra (Mollusca: Bivalvia)en Chacopata, Estado Sucre, Venezuela  

Scientific Electronic Library Online (English)

Full Text Available Abstract in spanish La diversidad malacológica de una comunidad submareal de Arca zebra se estudió, desde septiembre, 1990 hasta septiembre, 1991, en Chacopata, Estado Sucre, Venezuela. Se identificaron 40 especies (24 de bivalvos y 16 de gasterópodos). Los parámetros de diversidad en número de la comunidad fueron bajos (H` = 2.087 bits /ind., J` = 0.392, Simpson = 0.528) cuando se comparan con otros reportes de áreas tropicales. Los datos del número de individuos por especies con el (more) rango conforman una línea recta ajustada por la serie logaritmica, con un índice de diversidad (a) de 5.66. Las máximas diversidades mensuales se observaron en septiembre, 1990 (1.63 bits/ind.) y julio, 1991 (1.60 bits/ind.), la mínima ocurrió en junio, 1991 (0.52 bits/ind.). De las 40 especies identificadas, la pepitona, Arca zebra fue la especie dominante en número (68.87 %) y en biomasa (72.34 %), seguida por Pinctada imbricata, Modiolus squamosus, Chama macerophyla y Anadara notabilis. Los gasterópodos predadores Phyllonotus pomum, Chicoreus brevifrons y Murex recurvirostris parecen tener relaciones tróficas con la especie dominante. La biomasa promedio total en peso húmedo con la concha (469.20 + 263 g m-2) es alta e indica que A. zebra, la especie dominante de rápido crecimiento, desempeña el papel más importante en la comunidad como un eficiente filtrador, que convierte el alimento planctónico en biomasa disponible, soportando una de las pesquerías más importantes de la región. Abstract in english The diversity of a subtidal epifaunal mollusk community was studied from September, 1990 to September, 1991 in Chacopata, Sucre State, Venezuela. There were 40 species (24 bivalves and 16 gastropods). The diversity indexes (H` = 2.087, J`=0.392, 1/D = 0.528) were low when compared with other tropical zones. Monthly diversity reached its maximum in September, 1990 (1.63 bits/ind.) and July, 1991 (1.60 bits/ind.); minimum diversity occurred in June, 1991 (0.52 bits/ind.). A (more) Log series model applied to species abundance data showed a straight line with a diversity index a of 5.56. Of 40 species identified, the turkeywing Arca zebra was dominant (69 % in number of individuals and 72 % of biomass) followed by Pinctada imbricata, Modiolus squamosus, Chama macerophyla and Anadara notabilis. The predatory snails Phyllonotus pomum, Chicoreus brevifrons and Murex recurvirostris seemed to have trophic relationships with A. zebra. The total mean biomass in wet weight (469.20 + 263g m-2, shell included) was high which indicates that A. zebra, a species with a rapid growth rate, occupies a central role in the assemblage as an efficient filter feeder that converts planktonic food into available biomass, supporting one of the most important fisheries in Venezuela.

Prieto, Antulio S.; Ruiz, Lilia J.; García, Natividad; Alvarez, Miyosky

2001-06-01

327

Investigation of geographic variation in the thermal tolerance of zebra mussels, Dreissena polymorpha  

Energy Technology Data Exchange (ETDEWEB)

Data previously collected from endemic northern European populations indicated a maximum, long-term upper thermal limit of 28{degrees}C for D. polymorpha, a temperature well below maximum, summer-daytime, surface water temperatures in the lower Mississippi River ({>=}30{degrees}C). Thus, it has been speculated that natural selection for thermal tolerance among zebra mussels in the warm waters may have led to development of genetically more thermally tolerant populations than presently occur in the cooler waters of the Great Lakes. In order to investigate this possibility, thermal tolerance times on continual exposure to a lethal temperature of 33{degrees}C were determined for samples of zebra mussels collected biweekly in the lower Mississippi River from 14 March through 18 October, 1994 and from the Niagara River on 24 May and 9 August 1994. Multiple factor ANOVA indicated that while there were differences in mean thermal tolerance times among acclimation groups and with time of collection, there was no difference in thermal tolerance between the Niagara and lower Mississippi River populations. Least Squares Analysis indicated that sample mean thermal tolerance times among lower Mississippi River mussels increased, suggestive of a seasonal pattern of thermal tolerance regulation which could not be eliminated by laboratory temperature acclimation. Such seasonal thermal tolerance acclimatization may make fouling populations of D. polymorpha more resistant to thermal mitigation during summer months. It may also partially account for the reduced thermal tolerance reported among northern European populations drawn from much cooler waters than those of the lower Great Lakes and lower Mississippi River. Lack of significant thermal tolerance differences between Niagara and lower Mississippi River zebra mussels suggests that there has been no selection for a thermally tolerant physiological race of D. polymorpha in the lower Mississippi River.

Hernandez, M.R.; McMahon, R.F. [Univ. of Texas, Arlington, TX (United States); Dietz, T.H. [Louisiana State Univ., Baton Rouge, LA (United States)

1995-06-01

328

Zebra Mussel control experiences at Detroit Edison Harbor Beach Power Plant  

Energy Technology Data Exchange (ETDEWEB)

The Detroit Edison Co. Harbor Beach Power Plant on Lake Huron in Michigan`s thumb and is comprised of one 100 MW coal-fired unit. Zebra mussels first were discovered during a routine inspection of the plant screen house in August 1991. The initial population of 5 mussels/m{sup 2} increased to 650 mussels/m{sup 2} by March 1992. During this eight-month period the plant began to experience problems with zebra mussels clogging small coolers, check valves, and miscellaneous service water connections. Although the mussels had not affected the unit`s availability, it was evident that they soon might if left uncontrolled. A treatment program was devised in 1992 to eliminate the mussels living in the screen house and inside the plant. Targeted in-plant systems included the condenser cooling supply lines, plant service water system, and plant fire fighting system. An oxygen scavenger (sodium sulfate) was used in conjunction with thermal treatment (saturated steam) to asphyxiate and heat the mussels over a several day period. Inspection dives in the screen house before and after treatment as well as subsequent in-plant equipment inspections have revealed the treatment to be successful. Complete mortality was achieved in the screen house and in-plant systems. By April, 1993, the zebra mussel colony had re-established itself in the plant screen house to a level of 400 mussels/m{sup 2}. In October 1993, the colony had grown to 2,600 mussels/m{sup 2}. A second treatment was scheduled and completed on October 18--21, 1993. Thermal treatment was used alone during this treatment episode in which 100% mortality again wax achieved. Test bags, an in-line viewport, and post treatment dive inspections confirmed that the treatment was completely successful. Population monitoring and treatments continue on a regular basis.

Harwood, D.B.; Buda, D.J. [Detroit Edison Co., Harbor Beach, MI (United States)

1994-12-31

329

Examination of the potential of chlorine dioxide for use in zebra mussel veliger control  

Energy Technology Data Exchange (ETDEWEB)

Dreissena polymorpha (zebra mussel) veligers were treated with various concentrations of chlorine dioxide and exposed at several time intervals to determine the effectiveness of this oxidant as a veliger control agent. The direction of this testing was based on previous studies which determined the effectiveness of chlorine dioxide as a molluscicide for adult zebra mussel control. Zebra mussel veligers were collected from the Niagara River shoreline at an untreated site and tested using filtered river water from the same source. All testing was conducted on site at an industrial plant in order to insure the integrity of veligers collected for this study. The plankton wheel method was used to examine the effects of chlorine dioxide. This methodology involves intense microscopic examination of the test organism prior to and after chemical exposure todeterminen molluscicidal efficacy. Veliger mortality was determined based on observations of veliger movement. Typical criteria for the determination of mortality was expanded to include four categories; veliger actively swimming, internal musculature movement, no internal musculature movement observed, however not necessarily indicating a mortality and obviously a mortality. The treatment levels ranged from 0.75 ppm - 2.0 ppm which are considered to simulate treatment levels in actual applications. Mortality levels ranged on average from 16%-42% based on 30 minute or 60 minute exposure times. The determination exposure time was based on water flow time intervals in actural applications. Sodium hypochlorite was also evaluated in order to compare the effectiveness of chlorine dioxide against this known veliger control agent. Testing resulted in chlorine dioxide providing significantly better veliger control than sodium hypochlorite under similar conditions.

Rusznak, L.; Smolik, N.; Hale, L.; Freymark, S. [Ashland Chemical Company, Drew Division, Boonton, NJ (United States)

1995-06-01

330

Mapping of pigmentation QTL on an anchored genome assembly of the cichlid fish, Metriaclima zebra.  

UK PubMed Central (United Kingdom)

BACKGROUND: Pigmentation patterns are one of the most recognizable phenotypes across the animal kingdom. They play an important role in camouflage, communication, mate recognition and mate choice. Most progress on understanding the genetics of pigmentation has been achieved via mutational analysis, with relatively little work done to understand variation in natural populations. Pigment patterns vary dramatically among species of cichlid fish from Lake Malawi, and are thought to be important in speciation. In this study, we crossed two species, Metriaclima zebra and M. mbenjii, that differ in several aspects of their body and fin color. We genotyped 798 SNPs in 160 F2 male individuals to construct a linkage map that was used to identify quantitative trait loci (QTL) associated with the pigmentation traits of interest. We also used the linkage map to anchor portions of the M. zebra genome assembly. RESULTS: We constructed a linkage map consisting of 834 markers in 22 linkage groups that spanned over 1,933 cM. QTL analysis detected one QTL each for dorsal fin xanthophores, caudal fin xanthophores, and pelvic fin melanophores. Dorsal fin and caudal fin xanthophores share a QTL on LG12, while pelvic fin melanophores have a QTL on LG11. We used the mapped markers to anchor 66.5% of the M. zebra genome assembly. Within each QTL interval we identified several candidate genes that might play a role in pigment cell development. CONCLUSION: This is one of a few studies to identify QTL for natural variation in fish pigmentation. The QTL intervals we identified did not contain any pigmentation genes previously identified by mutagenesis studies in other species. We expect that further work on these intervals will identify new genes involved in pigment cell development in natural populations.

O Quin CT; Drilea AC; Conte MA; Kocher TD

2013-04-01

331

Mapping of pigmentation QTL on an anchored genome assembly of the cichlid fish, Metriaclima zebra.  

Science.gov (United States)

BACKGROUND: Pigmentation patterns are one of the most recognizable phenotypes across the animal kingdom. They play an important role in camouflage, communication, mate recognition and mate choice. Most progress on understanding the genetics of pigmentation has been achieved via mutational analysis, with relatively little work done to understand variation in natural populations. Pigment patterns vary dramatically among species of cichlid fish from Lake Malawi, and are thought to be important in speciation. In this study, we crossed two species, Metriaclima zebra and M. mbenjii, that differ in several aspects of their body and fin color. We genotyped 798 SNPs in 160 F2 male individuals to construct a linkage map that was used to identify quantitative trait loci (QTL) associated with the pigmentation traits of interest. We also used the linkage map to anchor portions of the M. zebra genome assembly. RESULTS: We constructed a linkage map consisting of 834 markers in 22 linkage groups that spanned over 1,933 cM. QTL analysis detected one QTL each for dorsal fin xanthophores, caudal fin xanthophores, and pelvic fin melanophores. Dorsal fin and caudal fin xanthophores share a QTL on LG12, while pelvic fin melanophores have a QTL on LG11. We used the mapped markers to anchor 66.5% of the M. zebra genome assembly. Within each QTL interval we identified several candidate genes that might play a role in pigment cell development. CONCLUSION: This is one of a few studies to identify QTL for natural variation in fish pigmentation. The QTL intervals we identified did not contain any pigmentation genes previously identified by mutagenesis studies in other species. We expect that further work on these intervals will identify new genes involved in pigment cell development in natural populations. PMID:23622422

O Quin, Claire T; Drilea, Alexi C; Conte, Matthew A; Kocher, Thomas D

2013-04-27

332

Temporal variation in zebra mussel (Dreissena polymorpha) density structure the benthic food web and community composition on hard substrates in Lake Constance, Germany  

UK PubMed Central (United Kingdom)

Invasive species often influence existing biocenoses by altering their environment or facilitating the ecology of other species. Here we combined stable isotope analysis with quantitative benthic community sampling to investigate temporal variation in the influence of biodeposition of organic material (biodeposits) by the zebra mussel (Dreissena polymorpha) on the benthic food web in hard substrate habitats of Lake Constance, Germany. The accumulation of organic material excreted by zebra mussels (faeces and pseudofaeces) is hypothesised to implement a biodeposition based food web. By means of stable isotope analyses, we found that the feeding strategy of amphipods was dependent on the availability of zebra mussel biodeposits. The proportion of pelagic resources contributing to the diet (by ?13C) and trophic position (by ?15N) of amphipods were significantly and positively correlated to the production of zebra mussel biodeposits. Also, the benthic community in Lower Lake Constance showed a shift towards higher densities of the mayfly Caenis spp., Chironominae, and the caddisfly Ecnomus tenellus, which might act as links to higher trophic levels when more zebra mussel biodeposits were available. These results demonstrate that temporal variation in zebra mussel density, and thus in organic biodeposition, have a strong impact on the benthic communities and food web structure associated with hard substrates to the extent that there may be dependence on zebra mussel occurrence in such habitats in Lake Constance.

Gergs Rene?; Grey Jonathan; Rothhaupt Karl-Otto

2011-12-01

333

IMPACT OF THE DURATION OF BACTERIAL EXPOSURE ON ZEBRA MUSSEL MORTALITY  

Energy Technology Data Exchange (ETDEWEB)

These tests indicated that: (1) duration of exposure to bacterial strain CL0145A of Pseudomonas fluorescens is a key variable in obtaining zebra mussel mortality; (2) that given a choice of exposure periods up to 96 hr, the longer the exposure period, the higher the mean mortality that will be achieved; (3) that the first few hours that the mussels are exposed to the bacteria are the most important in achieving kill; (4) that the mortality achieved by exposure periods {>=}72 hr may be somewhat amplified by the degraded water quality conditions which can develop in recirculating water systems over such extended time periods.

Daniel P. Molloy

2002-01-21

334

Complex Zebra Patterns in Solar Radio Emission and New Generation Mechanisms  

Science.gov (United States)

Several complex uncommon zebra patterns in meter/ decimeter and microwave range are shown. It is difficult to interpret them as the regular harmonics within the framework of known models, e.g. based on the double plasma resonance (DPR) mechanism. Specifically, for this reason, only in the last 5 years about 10 works devoted to an improvement of the DPR mechanism were published, and 5 new models were proposed. We propose a new advanced model of ZP based on the explosive instability in the system of the weakly-relativistic mono-velocity beam of protons - the strongly nonisothermic plasma.

Chernov, G. P.; Fomichev, V. V.

335

Oscillating magnetic field disrupts magnetic orientation in Zebra finches, Taeniopygia guttata  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Zebra finches can be trained to use the geomagnetic field as a directional cue for short distance orientation. The physical mechanisms underlying the primary processes of magnetoreception are, however, largely unknown. Two hypotheses of how birds perceive magnetic information are mainly discussed, one dealing with modulation of radical pair processes in retinal structures, the other assuming that iron deposits in the upper beak of the birds are involved. Oscillating magnetic fields in the MHz range disturb radical pair mechanisms but do not affect magnetic particles. Thus, application of such oscillating fields in behavioral experiments can be used as a diagnostic tool to decide between the two alternatives. Methods In a setup that eliminates all directional cues except the geomagnetic field zebra finches were trained to search for food in the magnetic north/south axis. The birds were then tested for orientation performance in two magnetic conditions. In condition 1 the horizontal component of the geomagnetic field was shifted by 90 degrees using a helmholtz coil. In condition 2 a high frequently oscillating field (1.156 MHz) was applied in addition to the shifted field. Another group of birds was trained to solve the orientation task, but with visual landmarks as directional cue. The birds were then tested for their orientation performance in the same magnetic conditions as applied for the first experiment. Results The zebra finches could be trained successfully to orient in the geomagnetic field for food search in the north/south axis. They were also well oriented in test condition 1, with the magnetic field shifted horizontally by 90 degrees. In contrast, when the oscillating field was added, the directional choices during food search were randomly distributed. Birds that were trained to visually guided orientation showed no difference of orientation performance in the two magnetic conditions. Conclusion The results indicate that zebra finches use a receptor that bases on radical pair processes for sensing the direction of the earth magnetic field in this short distance orientation behavior.

Keary Nina; Ruploh Tim; Voss Joe; Thalau Peter; Wiltschko Roswitha; Wiltschko Wolfgang; Bischof Hans-Joachim

2009-01-01

336

A model of so-called `Zebra' emissions in type IV radio bursts  

CERN Document Server

A simple mechanism for the generation of electromagnetic Zebra pattern emission is proposed. The mechanism is based on the generation of an ion-ring distribution in a magnetic mirror geometry in the presence of a properly directed field-aligned electric potential field. The ion-cyclotron maser then generates a number of electromagnetic ion-cyclotron harmonics which modulate the electron maser emission. The mechanism is capable of switching the emission on and off or amplifying it quasi-periodically which is a main feature of the observations.

Treumann, R A; Baumjohann, W

2011-01-01

337

Current Status of Health and Safety Issues of Sodium/Metal Chloride (Zebra) Batteries  

Energy Technology Data Exchange (ETDEWEB)

This report addresses environmental, health, and safety (EH&S) issues associated with sodium/ metal chloride batteries, in general, although most references to specific cell or battery types refer to units developed or being developed under the Zebra trademark. The report focuses on issues pertinent to sodium/metal chloride batteries and their constituent components; however, the fact that some ''issues'' arise from interaction between electric vehicle (EV) and battery design compels occasional discussion amid the context of EV vehicle design and operation. This approach has been chosen to provide a reasonably comprehensive account of the topic from a cell technology perspective and an applications perspective.

Trickett, D.

1998-12-15

338

The phytosociology of the De Rust section of the Mountain Zebra National Park, Eastern Cape  

Directory of Open Access Journals (Sweden)

Full Text Available As part of a vegetation survey programme for conservation areas in South Africa, the plant communities of the De Rust section of the Mountain Zebra National Park were investigated. From a TWINSPAN classification, refined by Braun-Blanquet procedures, 14 plant communities, which can be placed into six major groups, were identified. A clas- sification and description of these communities, as well as a vegetation map are presented. Associated gradients in habitat were identified by using an ordination algorithm (DECORANA). The diagnostic species as well as the prominent and less conspicuous species of the tree, shrub, herb and grass strata are outlined.

L.R. Brown; H. Bezuidenhout

2000-01-01

339

Field experiments investigating the Benthic Pelagic coupling over a zebra mussel be in the western basin of Lake Erie  

Energy Technology Data Exchange (ETDEWEB)

Unlike the relatively well-known unidirectional tidal flows in coastal marine environments, mixing in freshwater lakes is likely to be primarily wind driven and intermittent. Moreover, recent data indicates that flow rate affects zebra mussel filter feeding in a ramp-like manner not predicted by conventional static-flow models. Both of these outcomes indicate that direct measurements of the physical transport processes and the resultant biology of filter feeding must be made in situ to begin to understand the impact of zebra mussels on the pelagic foodwebs. The purpose of the following paper is to report the results of a preliminary study of the biophysical factors that relate to the benthic-pelagic coupling in a zebra mussel bed within the western basin of Lake Erie. Althoug work is still in progress, our preliminary results indicate a complex flow field over the zebra mussel bed. By means of a simple model, we have demonstrated that the extrapolation of individual laboratory-based feeding rates to a field situation leads to a significant overestimation of the actual feeding rates. Further work is in progress to refine the model to allow for vertical variability in organic concentration, a more accurate prescription of the turbulent transport or organic material above the bed and to validate other model assumptions such as the assumption of two-dimensional flow over the bed.

Loewen, M.R.; Cozzi, P. [Univ. of Toronto, Ontario (Canada); Hamblin, P.F. [National Water Research Institute, Burlington, Ontario (Canada); Ackerman, J.D. [Univ. of Northern British Columbia, Prince George (Canada)

1995-06-01

340

Karyotypic conservatism in samples of Characidium cf. zebra (Teleostei, Characiformes, Crenuchidae): Physical mapping of ribosomal genes and natural triploidy  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Basic and molecular cytogenetic analyses were performed in specimens of Characidium cf. zebra from five collection sites located throughout the Tietê, Paranapanema and Paraguay river basins. The diploid number in specimens from all samples was 2n = 50 with a karyotype composed of 32 metacentric and ...

Pansonato-Alves, José Carlos; Oliveira, Claudio; Foresti, Fausto

 
 
 
 
341

Bioavailability of particulate metal to zebra mussels: Biodynamic modelling shows that assimilation efficiencies are site-specific  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study investigates the ability of the biodynamic model to predict the trophic bioaccumulation of cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni) and zinc (Zn) in a freshwater bivalve. Zebra mussels were transplanted to three sites along the Seine River (France) and collected monthly for 1...

Bourgeault, Adeline; Gourlay-france, Catherine; Priadi, Cindy; Ayrault, Sophie; Tusseau-vuillemin, Marie-helene

342

Aspects of pathogen genomics, diversity, epidemiology, vector dynamics and disease management for a newly emerged disease of potato: Zebra Chip  

Science.gov (United States)

An overview is provided for the aspects of history, biology, genomics, genetics and epidemiology of zebra chip (ZC), a destructive disease of potato (Solanum tuberosum L.) that represents a major threat to potato industries in the US as well as other potato production regions in the world. The dise...

343

Establishing and fine-tuning an in planta system for potato zebra chip disease research in California  

Science.gov (United States)

We have acquired an APHIS-PPQ permit to work on “Candidatus Liberibacter solanacearum” at the USDA-ARS San Joaquin Valley Agricultural Sciences Center in Parlier, California. “Ca. L. solanacearum”, associated with Zebra chip disease (ZCD) of potato. This bacterium is currently unculturable in vitro....

344

Relationship of potato biochemical responses to ‘Candidatus Liberibacter solanacearum’, causal agent of zebra chip, to disease progression  

Science.gov (United States)

Zebra chip disease is an emerging threat to potato production in the United States and elsewhere. Knowledge of how potato hosts respond to the presumptive causal agent, ‘Candidatus Liberibacter solanacearum’ (CLS), will aid with efforts to breed potatoes more tolerant to infections by this bacterium...

345

Different potato cultivars may vary in zebra chip symptoms and associated physiological changes when infected by 'Candidatus Liberibacter solanacearum'  

Science.gov (United States)

Zebra chip disease (ZC) is an increasingly important disease for potato production in the United States and elsewhere, as it causes undesirable browning symptoms in both fresh and fried potatoes. ZC is putatively caused by ‘Candidatus Liberibacter solanacearum’ (Lso), a bacterium which is spread by ...

346

The effects of Zebra Chip disease development and bacterial titer on biochemical properties in relation to the time of infection  

Science.gov (United States)

Potato tuber biochemical responses to ‘Candidatus’ Liberibacter solanacearum (Lso), the causal agent of Zebra chip disease, were evaluated both within infected tubers and across different infection dates. Tuber biochemistry also was related to symptom severity and bacterial titer. Symptom severity w...

347

Complete genome sequence analyses and functional implications of ‘Candidatus Liberibacter solanacearum’, the bacterium associated with potato zebra chip diseases  

Science.gov (United States)

Zebra Chip (ZC) is an emerging plant disease that causes the decline of potato shoots and generally results in unusable tubers. ZC is characterized by discoloration or striped pattern of necrosis of tubers. Fried chips from ZC-diseased tubers are commercially unacceptable. The disease has significan...

348

Caractérisation de la propriété de la protéine ZEBRA du virus Epstein-Barr à pénétrer dans les cellules  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Il a été récemment démontré que l'activateur de transcription ZEBRA du virus Epstein-Barr contenant un motif "basic-leucine zipper (bZIP)" traverse la membrane externe des cellules vivantes et s'accumule dans le noyau des lymphocytes. Durant mon travail de thèse, j'ai étudié la possibilité d'utilise...

Rothe, Romy

349

Afferent connections of the ectostriatum and visual wulst in the zebra finch (Taeniopygia guttata castanotis Gould) — an HRP study  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Afferent connections of the two main areas in the telencephalon, the visual wulst and the ectostriatum, were traced in the zebra finch by injection of horseradish peroxidase and staining with tetramethylbenzidine (TMB). Nuclei projecting to the hyperstriatum accessorium (HA) or the HIS region (lamin...

Nixdorf, Barbara; Bischof, Hans-Joachim

350

Multiplex real-time PCR for detection, identification and quantification of "Candidatus Liberibacter solanacearum" in potato plants with zebra chip  

Science.gov (United States)

A new ‘Candidatus Liberibacter species’, Ca Liberibacter psyllarous’ (Lps) was found to be consistently associated with a newly emerging potato zebra chip (ZC) disease in Texas and other southwestern states in the U.S. This species is nearly identical on the basis of 16S rDNA sequences to that repo...

351

Further Evidence that Zebra Chip Potato Disease in the Lower Rio Grande Valley of Texas is Associated with Bactericera cockerelli  

Science.gov (United States)

Zebra chip (ZC) is an important and emerging potato disease that is causing millions of dollars in losses to both potato producers and processors in the southwestern United States, Texas in particular. This disease is characterized by symptoms that develop in fried chips from infected potato tubers ...

352

Zebra Chip disease and potato biochemistry: Tuber physiological changes in response to ‘Candidatus Liberibacter solanacearum’ infection over time  

Science.gov (United States)

Zebra chip disease (ZC), putatively caused by ‘Candidatus Liberibacter solanacearum’ (Lso), is of increasing concern to potato production in Mexico, the United States, and New Zealand. However, little is known about host tuber physiological changes that result in ZC symptom formation. This study exp...

353

Inheritance and longevity of infectious pancreatic necrosis virus in the zebra fish, Brachydanio rerio (Hamilton-Buchanan).  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Zebra fish (Brachydanio rerio) were injected with infectious pancreatic necrosis virus (IPNV) and then spawned to determine whether the virus was passed on to the eggs, and if it was, how long it remained in the free-swimming F1. The mating variations included parents receiving one or two injections...

Seeley, R J; Perlmutter, A; Seeley, V A

354

Tuber transmission of ‘Candidatus Liberibacter solanacearum' and its association with zebra chip on potato in New Zealand  

UK PubMed Central (United Kingdom)

Zebra chip, an emerging disease of potatoes, has recently been associated with ‘Candidatus Liberibacter solanacearum' in New Zealand. The phloem-limited bacterium is known to be vectored by the tomato potato psyllid (Bactericera cockerelli). In this study, the role of tuber transmission in the spread of Ca. L. solanacearum was investigated by re-planting potato tubers infected with Ca. L. solanacearum in the absence of the psyllid. Nested PCR demonstrated that Ca. L. solanacearum could be transmitted from the mother tubers both to the foliage of growing plants and to progeny tubers, resulting in symptomatic and asymptomatic plants. Of 62 Ca. L. solanacearum-infected tubers four did not sprout symptomatic of zebra chip. A further two plants developed foliar symptoms associated with zebra chip during the growing season and died prematurely. Fifty-six of the infected tubers produced asymptomatic plants, although Ca. L. solanacearum was detected in the foliage of 39 of them indicative of transmission into asymptomatic progeny plants. At harvest, Ca. L. solanacearum was found in the daughter tubers of only five of the 39 asymptomatic plants, and only one of these plants was found to have zebra chip symptoms in the daughter tubers. Our results show that tuber transmission of Ca. L. solanacearum could play a role in the life cycle of this pathogen, providing a source for acquisition by Bactericera cockerelli and for movement of the pathogen to other regions of New Zealand via transport of seed tubers.

Pitman AndrewR; Drayton GabbyM; Kraberger SimonaJ; Genet RussellA; Scott IanAW

2011-03-01

355

Zebra processes of oil recovery using fireflood and waterflood in alternate sands in a multi-sand environment  

Energy Technology Data Exchange (ETDEWEB)

This paper presents a new process of oil recovery, namely, the zebra process, which is specifically advantageous to use in heavy oil reservoirs that exist in multiple sands. This process uses firefloods and waterfloods in alternate sands. The firefloods serve as formation preheaters which reduce the oil viscosities in the neighboring sands so that these sands, normally not amenable to waterfloods because of high viscosity, can be waterflooded with ease. The exciting news is that the air compression cost in firefloods can be reduced by a factor of three with a proper application of the zebra process. This great savings in air compression cost is possible because the heat that is normally lost to the overburden and underburden in firefloods is now being put to good use, by preheating the neighboring sands. Examples are given on zebraing several idealized sand-shale sequences involving three-, five-, six-, and seven-sand reservoirs, and also zebraing two actual sand-shale sequences, both involving five-sand reservoirs.

Chu, C. [Texaco, Inc., Houston, TX (United States)

1995-12-31

356

Evaluation of the Toxic Effects of Clozapine in Zebra fish (Danio rerio) embryos with the Fish Embryo Toxicity Test  

Directory of Open Access Journals (Sweden)

Full Text Available Clozapine (an atypical antipsychotic drug) is indicated in treatment-refractory schizophrenia. Antipsychotics have been reported to have cardiotoxic effects in humans.The zebra fish (Danio rerio) is a tropical cyprinid used in toxicological research. In the present study, the toxicity of clozapine was evaluated in zebra fish embryos with the aid of the fish embryo toxicity test (FET). The endpoints monitored included circulation, heart rate, pericardial oedema, tail extension, spinal deformation, hatching time, coagulation and death. Clozapine was tested at five different concentrations ranging from 1 ?g/L to 10 mg/L. The toxic effects observed were a marked bradycardia at 10 mg/L and various abnormalities in the zebra fish embryos exposed to clozapine at 1 ?g/L to 10 mg/L. Based on the results obtained in this study, clozapine is toxic to zebra fish embryos and its level in the aquatic environment should be closely monitored in order to forestall adverse effects on the reproductive capabilities and survival of aquatic organisms.

M.G. Akande,; S. Orn,; L. Norrgren

2010-01-01

357

Parasitism can be a confounding factor in assessing the response of zebra mussels to water contamination  

International Nuclear Information System (INIS)

Biological responses measured in aquatic organisms to monitor environmental pollution could be also affected by different biotic and abiotic factors. Among these environmental factors, parasitism has often been neglected even if infection by parasites is very frequent. In the present field investigation, the parasite infra-communities and zebra mussel biological responses were studied up- and downstream a waste water treatment plant in northeast France. In both sites, mussels were infected by ciliates and/or intracellular bacteria, but prevalence rates and infection intensities were different according to the habitat. Concerning the biological responses differences were observed related to the site quality and the infection status. Parasitism affects both systems but seemed to depend mainly on environmental conditions. The influence of parasites is not constant, but remains important to consider it as a potential confounding factor in ecotoxicological studies. This study also emphasizes the interesting use of integrative indexes to synthesize data set. Highlights: ? Study of potential bias associated with the use of infected zebra mussels in ecotoxicological studies. ? Presence of infected mussels on banks and channels, up- and downstream a waste water treatment plant. ? Parasitism influence on biological responses dependent of mussel population history. ? Integrative index, an interesting tool to synthesize the set of biological data. - Parasitism influence on the host physiology would be strongly dependent on environmental conditions but remains a potential confounding factor in ecotoxicological studies.

2012-01-01

358

Involvement of apoptosis in host-parasite interactions in the zebra mussel.  

UK PubMed Central (United Kingdom)

The question of whether cell death by apoptosis plays a biological function during infection is key to understanding host-parasite interactions. We investigated the involvement of apoptosis in several host-parasite systems, using zebra mussels Dreissena polymorpha as test organisms and their micro- and macroparasites. As a stress response associated with parasitism, heat shock proteins (Hsp) can be induced. In this protein family, Hsp70 are known to be apoptosis inhibitors. Mussels were diagnosed for their respective infections by standard histological methods; apoptosis was detected using the TUNEL methods on paraffin sections and Hsp70 by immunohistochemistry on cryosections. Circulating hemocytes were the main cells observed in apoptosis whereas infected tissues displayed no or few apoptotic cells. Parasitism by intracellular bacteria Rickettsiales-like and the trematode Bucephalus polymorphus were associated with the inhibition of apoptosis whereas ciliates Ophryoglena spp. or the trematode Phyllodistomum folium did not involve significant differences in apoptosis. Even if some parasites were able to modulate apoptosis in zebra mussels, we did not see evidence of any involvement of Hsp70 on this mechanism.

Minguez L; Brulé N; Sohm B; Devin S; Giambérini L

2013-01-01

359

Is there a link between shell morphology and parasites of zebra mussels?  

UK PubMed Central (United Kingdom)

The shell morphology of zebra mussels, Dreissena polymorpha, was analyzed to determine if alterations in shell shape and asymmetry between valves were related to its infection status, i.e. infected or not by microparasites like ciliates Ophryoglena spp. or intracellular bacteria Rickettsiales-like organisms (RLOs), and by macroparasites like trematodes Phyllodistomum folium and Bucephalus polymorphus. For microparasites, two groups of mussels were observed depending on shell measurements. Mussels with the more concave shells were the most parasitized by ciliates. This could be more a consequence than a cause and we hypothesized that a modification of the water flow through the mantle cavity could promote the infection with a ciliate. There were more RLOs present in the most symmetrical individuals. A potential explanation involved a canalization of the left-right asymmetry as a by-product of the parasite infection. Trematode infections were associated with different responses in valve width. Females infected by P. folium displayed significantly higher symmetry in valve width compared with non-infected congeners, whereas the infection involved an opposite pattern in males. B. polymorphus was also linked to a decrease in valve width asymmetry. This study suggested that a relationship exists between parasitism and shell morphology through the physiological condition of host zebra mussels.

Minguez L; Lang AS; Beisel JN; Giambérini L

2012-02-01

360

Transcriptomic seasonal variations in a natural population of zebra mussel (Dreissena polymorpha).  

UK PubMed Central (United Kingdom)

The zebra mussel Dreissena polymorpha is a Caspian Sea bivalve that colonized freshwater bodies worldwide during the XX century. To analyze the impact of seasonal and environmental variations on the physiology and metabolism of this invasive species, we developed a custom microarray using 4057 publicly available DNA sequences from Dreissena and other related genera. Transcriptome profiles were analyzed using half-body samples from a relatively clean site (Riba-Roja, low Ebro River, N.E. Spain), at three different stages of the annual cycle: Pre-spawning (February), spawning (June), and gonad resorption (September). Transcripts from a total of 745 unique sequences showed significant changes among these three groups of samples. Functional characterization of these transcripts based on their closest known homologues showed that genes involved in stress defense (oxidative and infection) were overrepresented in September, whereas genes related to reproductive functions were overrepresented in the spawning and pre-spawning periods. This transcriptomic information can help to identify developmental stages at which the organism is more vulnerable for future control strategies. These data will also contribute to the implementation of gene expression-based assays for pollution monitoring in water bodies harboring stable zebra mussel populations.

Navarro A; Campos B; Barata C; Piña B

2013-06-01

 
 
 
 
361

Vitellogenin cleavage products as indicators for toxic stress in zebra fish embryos: a proteomic approach.  

Science.gov (United States)

Vitellogenins (Vtgs) are the major yolk proteins in all oviparous animals. Systematic and regulated processing of these during embryogenesis is crucial for embryonic development. In the present study, toxicant-induced disturbance of Vtg degradation processes during Danio rerio (DR) embryogenesis was analysed to establish a sensitive tool for monitoring toxic stress at the molecular level. A 2-DE-based proteomic approach for whole DR embryos was established to study Vtg cleavage products (lipovitellin (Lv) derivatives). Ethanol was chosen as a positive control for a toxicity related change in the proteome of whole zebra fish embryos. Protein extracts from embryos treated with two ethanol concentrations, 0.5 and 2% v/v, showing either no or very strong visible effects, like absent heartbeat and blood circulation, were examined. Significant changes in the Lv pattern were detected for both conditions. The results are interpreted as scope for the use of the high abundant Lv derivatives as sensitive stress indicators in zebra fish embryos reflecting the overall fitness of the intact organisms. PMID:18022936

Gündel, Ulrike; Benndorf, Dirk; von Bergen, Martin; Altenburger, Rolf; Küster, Eberhard

2007-12-01

362

Vitellogenin cleavage products as indicators for toxic stress in zebra fish embryos: a proteomic approach.  

UK PubMed Central (United Kingdom)

Vitellogenins (Vtgs) are the major yolk proteins in all oviparous animals. Systematic and regulated processing of these during embryogenesis is crucial for embryonic development. In the present study, toxicant-induced disturbance of Vtg degradation processes during Danio rerio (DR) embryogenesis was analysed to establish a sensitive tool for monitoring toxic stress at the molecular level. A 2-DE-based proteomic approach for whole DR embryos was established to study Vtg cleavage products (lipovitellin (Lv) derivatives). Ethanol was chosen as a positive control for a toxicity related change in the proteome of whole zebra fish embryos. Protein extracts from embryos treated with two ethanol concentrations, 0.5 and 2% v/v, showing either no or very strong visible effects, like absent heartbeat and blood circulation, were examined. Significant changes in the Lv pattern were detected for both conditions. The results are interpreted as scope for the use of the high abundant Lv derivatives as sensitive stress indicators in zebra fish embryos reflecting the overall fitness of the intact organisms.

Gündel U; Benndorf D; von Bergen M; Altenburger R; Küster E

2007-12-01

363

Radio continua modulated by waves: Zebra patterns in solar and pulsar radio spectra?  

Science.gov (United States)

Aims: We aim to answer the question how waves with plasma density variations affect the radio continua generated by the plasma emission mechanism. Methods: We built a simple semi-empirical model of the radio continuum modulation. Assuming that the waves with density variations are in the source of this radio continuum, we modeled the artificial radio spectrum, which we compared with observed spectra. Results: We show that the waves with density variations modulate the radio continua generated by the plasma emission mechanism. Considering a single slow magnetoacoustic wave, we model the radio spectra, which resemble solar zebra patterns. We show that this modulation generates zebra effects even when the radio continuum is composed of many spiky bursts. Generalizing from one single wave to a wave turbulence we find that the computed radio spectrum is similar to so-called lace bursts. Finally, using the same procedure, but for fast magnetoacoustic waves, we modeled the radio spectrum similar to that observed during the interpulse phase of the radio emission of the Crab Nebula pulsar.

Karlický, M.

2013-04-01

364

Comparisons of different methods to train a young zebra finch (Taeniopygia guttata) to learn a song.  

UK PubMed Central (United Kingdom)

Like humans, oscine songbirds exhibit vocal learning. They learn their song by imitating conspecifics, mainly adults. Among them, the zebra finch (Taeniopygia guttata) has been widely used as a model species to study the behavioral, cellular and molecular substrates of vocal learning. Various methods using taped song playback have been used in the laboratory to train young male finches to learn a song. Since different protocols have been applied by different research groups, the efficiency of the studies cannot be directly compared. The purpose of our study was to address this problem. Young finches were raised by their mother alone from day post hatching (dph) 10 and singly isolated from dph 35. One week later, exposure to a song model began, either using a live tutor or taped playback (passive or self-elicited). At dph 100, the birds were transferred to a common aviary. We observed that one-to-one live tutoring is the best method to get a fairly complete imitation. Using self-elicited playback we observed high inter-individual variability; while some finches learned well (including good copying of the song model), others exhibited poor copying. Passive playback resulted in poor imitation of the model. We also observed that finches exhibited vocal changes after dph 100 and that the range of these changes was negatively related to their imitation of the song model. Taken together, these results suggest that social aspects are predominant in the success outcome of song learning in the zebra finch.

Derégnaucourt S; Poirier C; Kant AV; Linden AV; Gahr M

2013-06-01

365

Differences in metal sequestration between zebra mussels from clean and polluted field locations  

International Nuclear Information System (INIS)

[en] Organisms are able to detoxify accumulated metals by, e.g. binding them to metallothionein (MT) and/or sequestering them in metal-rich granules (MRG). The different factors involved in determining the capacity or efficiency with which metals are detoxified are not yet known. In this work we studied how the sub-cellular distribution pattern of cadmium, copper and zinc in whole tissue of zebra mussels from clean and polluted surface waters is influenced by the total accumulated metal concentration and by its physiological condition. Additionally we measured the metallothionein concentration in the mussel tissue. Metal concentration increased gradually in the metal-sensitive and detoxified sub-cellular fractions with increasing whole tissue concentrations. However, metal concentrations in the sensitive fractions did not increase to the same extent as metal concentrations in whole tissues. In more polluted mussels the contribution of MRG and MT became more important. Nevertheless, metal detoxification was not sufficient to prevent metal binding to heat-sensitive low molecular weight proteins (HDP fraction). Finally we found an indication that metal detoxification was influenced by the condition of the zebra mussels. MT content could be explained for up to 83% by variations in Zn concentration and physiological condition of the mussels.

2009-06-04

366

Autoradiographic localization of nicotinic acetylcholine receptors in the brain of the zebra finch (Poephila guttata)  

International Nuclear Information System (INIS)

[en] We have localized nicotinic acetylcholine receptors in the zebra finch brain by using three 125I-labelled ligands: alpha bungarotoxin and two monoclonal antibodies to neuronal nicotinic receptors. Unfixed brains from intact adult male and female zebra finches were prepared for in vitro autoradiography. Low-resolution film autoradiograms and high-resolution emulsion autoradiograms were prepared for each of the three ligands. The major brain structures that bind all three of the ligands are hippocampus; hyperstriatum dorsalis; hyperstriatum ventralis; nucleus lentiformis mesencephali; nucleus pretectalis, some layers of the optic tectum; nucleus mesencephalicus lateralis; pars dorsalis; locus ceruleus; and all cranial motor nuclei except nucleus nervi hypoglossi. The major structures labelled only by [125I]-alpha bungarotoxin binding included hyperstriatum accessorium and the nuclei: preopticus medialis, medialis hypothalami posterioris, semilunaris, olivarius inferior, and the periventricular organ. Of the song control nuclei, nucleus magnocellularis of the anterior neostriatum; hyperstriatum ventralis, pars caudalis; nucleus intercollicularis; and nucleus hypoglossus were labelled. The binding patterns of the two antibodies were similar to one another but not identical. Both labelled nucleus spiriformis lateralis and nucleus geniculatus lateralis, pars ventralis especially heavily and also labelled the nucleus habenula medialis; nucleus subpretectalis; nucleus isthmi, pars magnocellularis; nucleus reticularis gigantocellularis; nucleus reticularis lateralis; nucleus tractus solitarii; nucleus vestibularis dorsolateralis; nucleus vestibularis lateralis; nucleus descendens nervi trigemini; and the deep cerebellar nuclei

1988-08-08

367

Heterospecific exposure affects the development of secondary sexual traits in male zebra finches (Taeniopygia guttata).  

UK PubMed Central (United Kingdom)

In many animal species, social signals can affect the reproductive physiology and behaviour of conspecifics. In a few species that exhibit vocal learning, exposure to conspecific and sometimes heterospecific sounds can also influence their vocal development. Here we show that heterospecific exposure can affect the development of secondary sexual traits of male zebra finches (Taeniopygia guttata). In a first experiment, we trained young males with a passive playback of domesticated canary (Serinus canaria) song. Song playback enhanced the sexual development of the birds: they started to sing during the presentation of a video clip of a female earlier during development and exhibited secondary sexual plumage ornaments faster than males of the control group kept in silence. Two out of five birds exhibited clear evidence of imitation of canary song. In a second experiment, we raised young male finches with young male canaries in pairs until adulthood. Again, the live contact with a heterospecific companion affected the development of plumage ornaments in finches. We also observed some evidences of vocal convergence, both for calls and song. Moreover, young males of both species could recognize the call of their heterospecific companion when adults. These results suggest that heterospecific exposure can affect both the sexual and the vocal development of the zebra finch and can have long lasting effects. This article is part of a Special Issue entitled: insert SI title.

Gehrold A; Leitner S; Laucht S; Derégnaucourt S

2013-03-01

368

Does sex matter? Differential responses to corticosterone administration in the zebra finch.  

Science.gov (United States)

Because of potentially deleterious effects of chronic stress, physiological measurements of stress hormones (in birds, corticosterone (CORT)) are often used to determine the consequences of natural or human-induced change. Often, it is assumed that CORT levels will be similar between the sexes and the results are pooled. However, recent studies have reported sex differences in CORT concentrations in avian species. As zebra finches (Taeniopygia guttata) are one of the most widely used bird species in laboratory studies worldwide, potential sex-specific differences in hormone metabolism, as well as the clearance rate of oral doses of exogenous CORT, are highly relevant. The results of this study show that female zebra finches have a significantly higher baseline CORT than males, which could partially be a product of differential responses to semi-isolation. In addition, a single dose of exogenous CORT resulted in different blood profiles between the sexes over time, though exogenous CORT was cleared from blood within 90min following treatment in both sexes. Interestingly, exposure to multiple doses of exogenous CORT resulted in elevated CORT levels 24h after treatment in both sexes. These results highlight the need for further investigations into potential sex differences in hormone metabolism, as well as possible cumulative effects of repeated stress. PMID:24035000

Khan, Nicola; Robert, Kylie

2013-08-28

369

Estradiol modulates neurotransmitter concentrations in the developing zebra finch song system.  

UK PubMed Central (United Kingdom)

The neural song system in zebra finches is highly sexually dimorphic; only males sing and the brain regions controlling song are far larger in males than females. Estradiol (E2) administered during development can partially masculinize both structure and function. However, additional mechanisms, including those through which E2 may act, remain unclear. Male and female zebra finches were treated with E2 or control vehicle from post-hatching days 3 through 25, at which time norepinephrine (NE), dopamine (DA) and serotonin (5-HT) were measured in individual nuclei of the song system. Main effects of sex were not detected. However, E2 increased NE in the robust nucleus of the arcopallium (RA). In HVC (proper name), the hormone decreased 5-HT across the two sexes and increased DA in females only. These effects suggest that, while baseline levels of these neurotransmitters may not contribute to sexually dimorphic development of the song system, they could play specific roles in functions common to both sexes and/or in modification of the song system by exogenous E2.

Wade J; Peabody C; Tang YP; Qi L; Burnett R

2013-06-01

370

Digital atlas of the zebra finch (Taeniopygia guttata) brain: A high-resolution photo atlas.  

UK PubMed Central (United Kingdom)

We describe a set of new comprehensive, high-quality, high-resolution digital images of histological sections from the brain of male zebra finches (Taeniopygia guttata) and make them publicly available through an interactive website (http://zebrafinch.brainarchitecture.org/). These images provide a basis for the production of a dimensionally accurate and detailed digital nonstereotaxic atlas. Nissl- and myelin-stained brain sections are provided in the transverse, sagittal, and horizontal planes, with the transverse plane approximating the more traditional Frankfurt plane. In addition, a separate set of brain sections in this same plane is stained for tyrosine hydroxylase, revealing the distribution of catecholaminergic neurons (dopaminergic, noradrenergic, and adrenergic) in the songbird brain. For a subset of sagittal sections we also prepared a corresponding set of drawings, defining and annotating various nuclei, fields, and fiber tracts that are visible under Nissl and myelin staining. This atlas of the zebra finch brain is expected to become an important tool for birdsong research and comparative studies of brain organization and evolution. J. Comp. Neurol. 521:3702-3715, 2013. © 2013 Wiley Periodicals, Inc.

Karten HJ; Brzozowska-Prechtl A; Lovell PV; Tang DD; Mello CV; Wang H; Mitra PP

2013-11-01

371

Digital atlas of the zebra finch (Taeniopygia guttata) brain: A high-resolution photo atlas.  

Science.gov (United States)

We describe a set of new comprehensive, high-quality, high-resolution digital images of histological sections from the brain of male zebra finches (Taeniopygia guttata) and make them publicly available through an interactive website (http://zebrafinch.brainarchitecture.org/). These images provide a basis for the production of a dimensionally accurate and detailed digital nonstereotaxic atlas. Nissl- and myelin-stained brain sections are provided in the transverse, sagittal, and horizontal planes, with the transverse plane approximating the more traditional Frankfurt plane. In addition, a separate set of brain sections in this same plane is stained for tyrosine hydroxylase, revealing the distribution of catecholaminergic neurons (dopaminergic, noradrenergic, and adrenergic) in the songbird brain. For a subset of sagittal sections we also prepared a corresponding set of drawings, defining and annotating various nuclei, fields, and fiber tracts that are visible under Nissl and myelin staining. This atlas of the zebra finch brain is expected to become an important tool for birdsong research and comparative studies of brain organization and evolution. J. Comp. Neurol. 521:3702-3715, 2013. © 2013 Wiley Periodicals, Inc. PMID:23896990

Karten, Harvey J; Brzozowska-Prechtl, Agnieszka; Lovell, Peter V; Tang, Daniel D; Mello, Claudio V; Wang, Haibin; Mitra, Partha P

2013-11-01

372

Skin-deep diagnosis: affective bias and zebra retreat complicating the diagnosis of systemic sclerosis.  

UK PubMed Central (United Kingdom)

Nearly half of medical errors can be attributed to an error of clinical reasoning or decision making. It is estimated that the correct diagnosis is missed or delayed in between 5% and 14% of acute hospital admissions. Through understanding why and how physicians make these errors, it is hoped that strategies can be developed to decrease the number of these errors. In the present case, a patient presented with dyspnea, gastrointestinal symptoms and weight loss; the diagnosis was initially missed when the treating physicians took mental short cuts and used heuristics as in this case. Heuristics have an inherent bias that can lead to faulty reasoning or conclusions, especially in complex or difficult cases. Affective bias, which is the overinvolvement of emotion in clinical decision making, limited the available information for diagnosis because of the hesitancy to acquire a full history and perform a complete physical examination in this patient. Zebra retreat, another type of bias, is when a rare diagnosis figures prominently on the differential diagnosis but the physician retreats for various reasons. Zebra retreat also factored in the delayed diagnosis. Through the description of these clinical reasoning errors in an actual case, it is hoped that future errors can be prevented or inspiration for additional research in this area will develop.

Miller CS

2013-01-01

373

A unified explanation of solar type IV dm continua and zebra patterns  

International Nuclear Information System (INIS)

[en] Both type IV dm continuum radiation and zebra patterns can have their origin in plasma waves at the upper hybrid frequency, which are excited by a loss-cone distribution of fast electrons superposed on the thermal background. If the inverse fractional density of fast electrons surpasses the ratio of the electron plasma frequency to the electron cyclotron frequency, instability only exists at those places in the corona where this ratio is integer, thus giving rise to zebra patterns. Some observations in favour of the present explanation are discussed. Upper limits to the magnetic field strength and the fast particle density in the source are derived from the observations. (orig.)[de] Sowohl die Kontinuumstrahlung des Typs IV dm als auch Zebramuster koennen ihren Ursprung in Plasmawellen an der oberen Hybridfrequenz haben, die von einer dem thermischen Hintergrund ueberlagernden Verlustkegelverteilung schneller Elektronen angeregt werden. Ist die umgekehrte fraktionierte Dichte schneller Elektronen groesser als das Verhaeltnis der Elektronenplasmafrequenz zur Elektronenzyklotronfrequenz, so findet sich Instabilitaet nur an denjenigen Stellen der Korona, an denen dieses Verhaeltnis integer ist, wodurch Zebramuster entstehen. Es werden einige Beobachtungen diskutiert, die diese Erklaerung unterstuetzen. Die oberen Grenzen der Feldstaerke und der Dichte schneller Teilchen in der Quelle werden aus den Beobachtungen abgeleitet. (orig./AK)

1975-01-01

374

Differences in metal sequestration between zebra mussels from clean and polluted field locations  

Energy Technology Data Exchange (ETDEWEB)

Organisms are able to detoxify accumulated metals by, e.g. binding them to metallothionein (MT) and/or sequestering them in metal-rich granules (MRG). The different factors involved in determining the capacity or efficiency with which metals are detoxified are not yet known. In this work we studied how the sub-cellular distribution pattern of cadmium, copper and zinc in whole tissue of zebra mussels from clean and polluted surface waters is influenced by the total accumulated metal concentration and by its physiological condition. Additionally we measured the metallothionein concentration in the mussel tissue. Metal concentration increased gradually in the metal-sensitive and detoxified sub-cellular fractions with increasing whole tissue concentrations. However, metal concentrations in the sensitive fractions did not increase to the same extent as metal concentrations in whole tissues. In more polluted mussels the contribution of MRG and MT became more important. Nevertheless, metal detoxification was not sufficient to prevent metal binding to heat-sensitive low molecular weight proteins (HDP fraction). Finally we found an indication that metal detoxification was influenced by the condition of the zebra mussels. MT content could be explained for up to 83% by variations in Zn concentration and physiological condition of the mussels.

Voets, Judith [Laboratory for Ecophysiology, Biochemistry and Toxicology, Department of Biology, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp (Belgium); Redeker, Erik Steen [Laboratory for Ecophysiology, Biochemistry and Toxicology, Department of Biology, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp (Belgium); Institute for Materials Research, Chemistry Division, Hasselt University, Agoralaan Building D G1-36, B 3590 Diepenbeek (Belgium); Blust, Ronny [Laboratory for Ecophysiology, Biochemistry and Toxicology, Department of Biology, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp (Belgium); Bervoets, Lieven, E-mail: Lieven.bervoets@ua.ac.be [Laboratory for Ecophysiology, Biochemistry and Toxicology, Department of Biology, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp (Belgium)

2009-06-04

375

Does sex matter? Differential responses to corticosterone administration in the zebra finch.  

UK PubMed Central (United Kingdom)

Because of potentially deleterious effects of chronic stress, physiological measurements of stress hormones (in birds, corticosterone (CORT)) are often used to determine the consequences of natural or human-induced change. Often, it is assumed that CORT levels will be similar between the sexes and the results are pooled. However, recent studies have reported sex differences in CORT concentrations in avian species. As zebra finches (Taeniopygia guttata) are one of the most widely used bird species in laboratory studies worldwide, potential sex-specific differences in hormone metabolism, as well as the clearance rate of oral doses of exogenous CORT, are highly relevant. The results of this study show that female zebra finches have a significantly higher baseline CORT than males, which could partially be a product of differential responses to semi-isolation. In addition, a single dose of exogenous CORT resulted in different blood profiles between the sexes over time, though exogenous CORT was cleared from blood within 90min following treatment in both sexes. Interestingly, exposure to multiple doses of exogenous CORT resulted in elevated CORT levels 24h after treatment in both sexes. These results highlight the need for further investigations into potential sex differences in hormone metabolism, as well as possible cumulative effects of repeated stress.

Khan N; Robert K

2013-10-01

376

Characterization and Epidemiological Significance of Potato Plants Grown from Seed Tubers Affected by Zebra Chip Disease  

UK PubMed Central (United Kingdom)

An emerging disease of potato in the United States, known as “Zebra Chip” or “Zebra Complex” (ZC), is increasing in scope and threatens to spread further. Here, we report on studies performed to understand the role of tuberborne ZC in the epidemiology of this disease. Depending on variety, up to 44% of ZC-affected seed tubers (ZCST) were viable, producing hair sprouts and weak plants. Chip discoloration in progeny tubers of ZCST was more severe than those from ZC-asymptomatic seed tubers but varied depending on whether progeny tubers or foliage were positive or negative for ‘Candidatus Liberibacter solanacearum’. A low percentage of greenhouse-grown plants produced by ZCST tested positive for ‘Ca. Liberibacter’. No adult potato psyllids became infective after feeding upon these plants but they did acquire ‘Ca. Liberibacter’ from field-grown plants produced by ZCST. Plants with new ZC infections near plants produced by ZCST were not significantly different from healthy plants, whereas plants affected with ZC from infectious potato psyllids had significantly more ZC infections near either plants produced by ZCST or healthy plants. We conclude that, in areas where ZC is currently established, plants produced by ZCST do not significantly contribute to ZC incidence and spread within potato fields.

Henne DC; Workneh F; Wen A; Price JA; Pasche JS; Gudmestad NC; Rush CM

2010-06-01

377

Heterospecific exposure affects the development of secondary sexual traits in male zebra finches (Taeniopygia guttata).  

Science.gov (United States)

In many animal species, social signals can affect the reproductive physiology and behaviour of conspecifics. In a few species that exhibit vocal learning, exposure to conspecific and sometimes heterospecific sounds can also influence their vocal development. Here we show that heterospecific exposure can affect the development of secondary sexual traits of male zebra finches (Taeniopygia guttata). In a first experiment, we trained young males with a passive playback of domesticated canary (Serinus canaria) song. Song playback enhanced the sexual development of the birds: they started to sing during the presentation of a video clip of a female earlier during development and exhibited secondary sexual plumage ornaments faster than males of the control group kept in silence. Two out of five birds exhibited clear evidence of imitation of canary song. In a second experiment, we raised young male finches with young male canaries in pairs until adulthood. Again, the live contact with a heterospecific companion affected the development of plumage ornaments in finches. We also observed some evidences of vocal convergence, both for calls and song. Moreover, young males of both species could recognize the call of their heterospecific companion when adults. These results suggest that heterospecific exposure can affect both the sexual and the vocal development of the zebra finch and can have long lasting effects. This article is part of a Special Issue entitled: insert SI title. PMID:23298888

Gehrold, Andrea; Leitner, Stefan; Laucht, Silke; Derégnaucourt, Sébastien

2013-01-06

378

Involvement of apoptosis in host-parasite interactions in the zebra mussel.  

Science.gov (United States)

The question of whether cell death by apoptosis plays a biological function during infection is key to understanding host-parasite interactions. We investigated the involvement of apoptosis in several host-parasite systems, using zebra mussels Dreissena polymorpha as test organisms and their micro- and macroparasites. As a stress response associated with parasitism, heat shock proteins (Hsp) can be induced. In this protein family, Hsp70 are known to be apoptosis inhibitors. Mussels were diagnosed for their respective infections by standard histological methods; apoptosis was detected using the TUNEL methods on paraffin sections and Hsp70 by immunohistochemistry on cryosections. Circulating hemocytes were the main cells observed in apoptosis whereas infected tissues displayed no or few apoptotic cells. Parasitism by intracellular bacteria Rickettsiales-like and the trematode Bucephalus polymorphus were associated with the inhibition of apoptosis whereas ciliates Ophryoglena spp. or the trematode Phyllodistomum folium did not involve significant differences in apoptosis. Even if some parasites were able to modulate apoptosis in zebra mussels, we did not see evidence of any involvement of Hsp70 on this mechanism. PMID:23785455

Minguez, Laëtitia; Brulé, Nelly; Sohm, Bénédicte; Devin, Simon; Giambérini, Laure

2013-06-13

379

Estradiol modulates neurotransmitter concentrations in the developing zebra finch song system.  

Science.gov (United States)

The neural song system in zebra finches is highly sexually dimorphic; only males sing and the brain regions controlling song are far larger in males than females. Estradiol (E2) administered during development can partially masculinize both structure and function. However, additional mechanisms, including those through which E2 may act, remain unclear. Male and female zebra finches were treated with E2 or control vehicle from post-hatching days 3 through 25, at which time norepinephrine (NE), dopamine (DA) and serotonin (5-HT) were measured in individual nuclei of the song system. Main effects of sex were not detected. However, E2 increased NE in the robust nucleus of the arcopallium (RA). In HVC (proper name), the hormone decreased 5-HT across the two sexes and increased DA in females only. These effects suggest that, while baseline levels of these neurotransmitters may not contribute to sexually dimorphic development of the song system, they could play specific roles in functions common to both sexes and/or in modification of the song system by exogenous E2. PMID:23628476

Wade, Juli; Peabody, Camilla; Tang, Yu Ping; Qi, Linda; Burnett, Robert

2013-04-27

380

Interactions between parasitism and biological responses in zebra mussels (Dreissena polymorpha): Importance in ecotoxicological studies.  

UK PubMed Central (United Kingdom)

Given that virtually all organisms are hosts for parasites, the investigation of the combined effects of contamination and parasitism is important in the framework of aquatic bioindication procedures. To assess the impact of such multistresses at the host cellular level, we sampled parasitized zebra mussel (Dreissena polymorpha) populations from two sites in northeast France that presented different levels of contamination. Experimental groups were formed based on parasite species and host gender and tested by histochemistry and automated image analysis for biological responses, such as structural changes of the lysosomal system and neutral lipid accumulation. Infected organisms displayed smaller and more numerous lysosomes compared with uninfected congeners, and infection further elevated the effect of the chemical contamination on this biomarker. In contrast, co-infection of females with selected parasites did produce inverse results, i.e. a more developed lysosomal system and neutral lipid depletion. Our data, therefore, suggest that parasitism in zebra mussels represents a potential confounding factor in ecotoxicological studies and must be taken into account in environmental risk assessment studies.

Minguez L; Meyer A; Molloy DP; Giambérini L

2009-10-01

 
 
 
 
381

Zebra finches and Dutch adults exhibit the same cue weighting bias in vowel perception.  

UK PubMed Central (United Kingdom)

Vocal tract resonances, called formants, are the most important parameters in human speech production and perception. They encode linguistic meaning and have been shown to be perceived by a wide range of species. Songbirds are also sensitive to different formant patterns in human speech. They can categorize words differing only in their vowels based on the formant patterns independent of speaker identity in a way comparable to humans. These results indicate that speech perception mechanisms are more similar between songbirds and humans than realized before. One of the major questions regarding formant perception concerns the weighting of different formants in the speech signal ("acoustic cue weighting") and whether this process is unique to humans. Using an operant Go/NoGo design, we trained zebra finches to discriminate syllables, whose vowels differed in their first three formants. When subsequently tested with novel vowels, similar in either their first formant or their second and third formants to the familiar vowels, similarity in the higher formants was weighted much more strongly than similarity in the lower formant. Thus, zebra finches indeed exhibit a cue weighting bias. Interestingly, we also found that Dutch speakers when tested with the same paradigm exhibit the same cue weighting bias. This, together with earlier findings, supports the hypothesis that human speech evolution might have exploited general properties of the vertebrate auditory system.

Ohms VR; Escudero P; Lammers K; ten Cate C

2012-03-01

382

Zebra finches and Dutch adults exhibit the same cue weighting bias in vowel perception.  

Science.gov (United States)

Vocal tract resonances, called formants, are the most important parameters in human speech production and perception. They encode linguistic meaning and have been shown to be perceived by a wide range of species. Songbirds are also sensitive to different formant patterns in human speech. They can categorize words differing only in their vowels based on the formant patterns independent of speaker identity in a way comparable to humans. These results indicate that speech perception mechanisms are more similar between songbirds and humans than realized before. One of the major questions regarding formant perception concerns the weighting of different formants in the speech signal ("acoustic cue weighting") and whether this process is unique to humans. Using an operant Go/NoGo design, we trained zebra finches to discriminate syllables, whose vowels differed in their first three formants. When subsequently tested with novel vowels, similar in either their first formant or their second and third formants to the familiar vowels, similarity in the higher formants was weighted much more strongly than similarity in the lower formant. Thus, zebra finches indeed exhibit a cue weighting bias. Interestingly, we also found that Dutch speakers when tested with the same paradigm exhibit the same cue weighting bias. This, together with earlier findings, supports the hypothesis that human speech evolution might have exploited general properties of the vertebrate auditory system. PMID:21761144

Ohms, Verena R; Escudero, Paola; Lammers, Karin; ten Cate, Carel

2011-07-15

383

Elimination rate constants of 36 PCBs in zebra mussels (Dreissena polymorpha) and exposure dynamics in the Lake St. Clair - Lake Erie corridor  

Energy Technology Data Exchange (ETDEWEB)

Zebra mussels have the potential to influence contaminant cycling in heavily infested water bodies because of their immense filtering capacity. The elimination kinetics of 36 PCB congeners were determined in zebra mussels, with shell lengths of 1.0-1.5 cm, collected from Lake St. Clair and Lake Erie. The mussels were calibrated to determine the time required to achieve chemical equilibrium with their environment. Bioavailable PCB congener concentrations, calculated with a steady-state model were determined. It was possible to quantify the role of the zebra mussels in regulating organic contaminant cycling in lakes. It was confirmed that they have the potential to regulate chemical transport and fate in aquatic ecosystems. It was suggested that because of their rapid kinetics zebra mussels could be an excellent choice as biomonitors to measure temporal and spatial levels of organic contaminants in lakes and rivers. 29 refs., 4 tabs., 1 fig.

Morrison, H. [Windsor Univ., ON (Canada). Great Lakes Inst.; Yankovich, T. [Trent Univ., Peterborough, ON (Canada); Lazar, R.; Haffner, D. [Windsor Univ., ON (Canada). Great Lakes Inst.

1995-12-01

384

Impact of Zebra Mussels ('Dreissna polymorpha') on the Sport Fishery of a Small, Thermally Stratified Inland Reservoir. Completion Report, July 1, 1993-June 30, 1997.  

Science.gov (United States)

We conducted a 4-year ecological study from 1993 to 1996 in Hargus Lake, a small stratified reservoir near Circleville, Ohio, following zebra mussel invasion and establishment. Our study mainly dealt with the interactions between lake stratification and z...

D. A. Culver N. Yu

1997-01-01

385

Comparative toxicity of single and combined mixtures of selected pollutants among larval stages of the native freshwater mussels (Unio elongatulus) and the invasive zebra mussel (Dreissena polymorpha).  

UK PubMed Central (United Kingdom)

This study evaluated the impact of biocides (tributyltin, chlorthalonil and Irgarol 1051) and of pollutants (copper, inorganic and methyl mercury and 4-nonylphenol) occurring in Ebro River (NE Spain) on early developmental stages of native Spanish freshwater and invasive zebra mussels. Toxicity tests were conducted with embryos and glochidia of zebra mussel (Dreissena polymorpha) and the naiad species Unio elongatulus, respectively. Toxicity was quantified in terms of median effective concentration (EC50) impairing embryogenesis and glochidia viability in single and combined mixture exposures. Irgarol 1051 was not toxic at concentrations below 40x10(3)nM. Zebra mussel embryos were on average 50 fold more sensitive to the studied pollutants than glochidia. Tributyltin was the most toxic compound with EC50s for zebra mussel embryos and glochidia, respectively, of 1.24 and 47.93 nM, followed by chlorothalonil (3.65, 176.58 nM), methyl mercury (7.06, 156.4 nM), inorganic mercury (3.64, 518.28 nM), copper (19.73, 1358.55 nM) and 4-nonylphenol (33.99, 1221.48 nM). Combined toxicity of Ebro River pollutants (copper, inorganic and methyl mercury and 4-nonylphenol) was greater than additive in zebra mussel embryos and additive in glochidia. These results indicated that contaminant levels that affect zebra mussel embryos are not toxic to early life stages of the naiad mussel species U. elongatulus.

Faria M; López MA; Fernández-Sanjuan M; Lacorte S; Barata C

2010-05-01

386

Song exposure regulates known and novel microRNAs in the zebra finch auditory forebrain.  

UK PubMed Central (United Kingdom)

BACKGROUND: In an important model for neuroscience, songbirds learn to discriminate songs they hear during tape-recorded playbacks, as demonstrated by song-specific habituation of both behavioral and neurogenomic responses in the auditory forebrain. We hypothesized that microRNAs (miRNAs or miRs) may participate in the changing pattern of gene expression induced by song exposure. To test this, we used massively parallel Illumina sequencing to analyse small RNAs from auditory forebrain of adult zebra finches exposed to tape-recorded birdsong or silence. RESULTS: In the auditory forebrain, we identified 121 known miRNAs conserved in other vertebrates. We also identified 34 novel miRNAs that do not align to human or chicken genomes. Five conserved miRNAs showed significant and consistent changes in copy number after song exposure across three biological replications of the song-silence comparison, with two increasing (tgu-miR-25, tgu-miR-192) and three decreasing (tgu-miR-92, tgu-miR-124, tgu-miR-129-5p). We also detected a locus on the Z sex chromosome that produces three different novel miRNAs, with supporting evidence from Northern blot and TaqMan qPCR assays for differential expression in males and females and in response to song playbacks. One of these, tgu-miR-2954-3p, is predicted (by TargetScan) to regulate eight song-responsive mRNAs that all have functions in cellular proliferation and neuronal differentiation. CONCLUSIONS: The experience of hearing another bird singing alters the profile of miRNAs in the auditory forebrain of zebra finches. The response involves both known conserved miRNAs and novel miRNAs described so far only in the zebra finch, including a novel sex-linked, song-responsive miRNA. These results indicate that miRNAs are likely to contribute to the unique behavioural biology of learned song communication in songbirds.

Gunaratne PH; Lin YC; Benham AL; Drnevich J; Coarfa C; Tennakoon JB; Creighton CJ; Kim JH; Milosavljevic A; Watson M; Griffiths-Jones S; Clayton DF

2011-01-01

387

Evolution of a cluster of innate immune genes (?-defensins) along the ancestral lines of chicken and zebra finch  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Avian ?-defensins (AvBDs) represent a group of innate immune genes with broad antimicrobial activity. Within the chicken genome, previous work identified 14 AvBDs in a cluster on chromosome three. The release of a second bird genome, the zebra finch, allows us to study the comparative evolutionary history of these gene clusters between from two species that shared a common ancestor about 100 million years ago. Results A phylogenetic analysis of the ?-defensin gene clusters in the chicken and the zebra finch identified several cases of gene duplication and gene loss along their ancestral lines. In the zebra finch genome a cluster of 22 AvBD genes were identified, all located within 125 Kbp on chromosome three. Ten of the 22 genes were found to be highly conserved with orthologous genes in the chicken genome. The remaining 12 genes were all located within a cluster of 58 Kbp and are suggested to be a result of recent gene duplication events that occurred after the galliformes- passeriformes split (G-P split). Within the chicken genome, AvBD6 was found to be a duplication of AvBD7, whereas the gene AvDB14 seems to have been lost along the ancestral line of the zebra finch. The duplicated ?-defensin genes have had a significantly higher accumulation of non-synonymous over synonymous substitutions compared to the genes that have not undergone duplication since the G-P split. The expression patterns of avian ?-defensin genes seem to be well conserved between chicken and zebra finch. Conclusion The genomic comparisons of the ?-defensins gene clusters of the chicken and zebra finch illuminate the evolutionary history of this gene complex. Along their ancestral lines, several gene duplication events have occurred in the passerine line after the galliformes-passeriformes split giving rise to 12 novel genes compared to a single duplication event in the galliformes line. After the duplication events, the duplicated genes have been subject to a relaxed selection pressure compared to the non-duplicated genes, thus supporting models of evolution by gene duplication.

Hellgren Olof; Ekblom Robert

2010-01-01

388

Tame zebra mussels at lower cost using ClO{sub 2}  

Energy Technology Data Exchange (ETDEWEB)

A potential cost-effective alternative to other oxidizing molluscicides, chlorine dioxide applied intermittently apparently achieves equivalent control of veliger settlement in cooling systems. Various techniques have been used with success for controlling zebra mussel infestation. Powerplant owners, however, continue to search for methods to minimize treatment costs. One example is a nuclear station located on the eastern shore of Lake Michigan, which has been able to control the mollusk with chlorine (in the form of sodium hypochlorite, generated on-site), non-oxidizing biocide, and mechanical removal of adult mussels. Recently, the plant evaluated the possibility of substituting chlorine dioxide (ClO{sub 2}) to achieve the same result more economically, without additional impact on the environment. Results indicate that initial shock treatment with ClO{sub 2} followed by intermittent application during the spawning season can provide adequate control at a lower cost.

Freymark, S.; Hale, L.

1996-01-01

389

The byssus of the zebra mussel (Dreissena polymorpha): spatial variations in protein composition.  

UK PubMed Central (United Kingdom)

The notorious biofouling organism Dreissena polymorpha (the zebra mussel) attaches to a variety of surfaces using a byssus, a series of protein threads that connect the animal to adhesive plaques secreted onto hard substrata. Here, the use of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) to characterize the composition of different regions of the byssus is reported. All parts of the byssus show mass peaks corresponding to small proteins in the range of 3.7-7 kDa, with distinctive differences between different regions. Indeed, spectra from thread and plaques are almost completely non-overlapping. In addition, several peaks were identified that are unique to the interfacial region of the plaque, and therefore likely represent specialized adhesive proteins. These results indicate a high level of control over the distribution of proteins, presumably with different functions, in the byssus of this freshwater species.

Gilbert TW; Sone ED

2010-10-01

390

Quagga and zebra mussel risk via veliger transfer by overland hauled boats  

Directory of Open Access Journals (Sweden)

Full Text Available Invasive quagga and zebra mussels (Dreissena rostriformis bugensis and Dreissena polymorpha, respectively) pose a great threat to USwaters. Recreational boats constitute a significant risk for spreading the organisms. Recreational boats circulate large amounts of raw waterwhen in use, and if not drained and dried correctly can transport many mussel larvae, called veligers. Veligers experience very high mortality rates; however, the number of potentially transported veligers can be a serious risk to non-infested bodies of water, especially if multiple boats are involved. The risk of veliger transport was calculated for Lake Mead and Lake Michigan using boat capacities for water circulation and specific veliger density data. Results illustrate the importance of draining, drying, and/or decontaminating recreational boats after use.

Larry B. Dalton; Sariah Cottrell

2013-01-01

391

Impact of European zebra mussel infestation to the electric power industry  

Energy Technology Data Exchange (ETDEWEB)

This paper reports on Dreissena polymorpha, the European freshwater zebra mussel, introduced to the Great Lakes in 1985. It is now found throughout Lakes St. Clair and Erie, in Green Bay, Lake Michigan and invaded western Lake Ontario by Fall 1989. As its planktonic veliger larva is dispersed on water currents and adults are transported by human and natural vectors, it is likely to spread throughout U.S. and southern Canadian freshwaters. Mussel accumulations impede flow, and aggravate sedimentation and corrosion. Settlement occurs at flow velocities less than 1.5-2.0 m/sec. Mussels foul intake structures, low-flow piping, steam condensors, heat exchangers, fire protection systems, and cooling tower basins. Monitoring of source waters for mussels and veligers allows initiation of control measures before macrofouling occurs. Mussel fouling should be prevented as removal is difficult and expensive.

McMahon, R.F. (Center for Biological Macrofouling Research, Univ. of Texas at Arlington, Arlington, TX (US))

1990-01-01

392

Occurrence of zebra mussel parasites: modelling according to contamination in France and the USA.  

UK PubMed Central (United Kingdom)

Parasites can be reliable tool in assessing the effects of ecosystem disturbances. However, they can respond in different ways and any changes in assemblages are not easily predictable. Descriptive modelling could be a first step since providing information on the relative importance of a pollutant on parasite occurrence. We chose the zebra mussel, as test organism and twelve sites in France and the United States. Contaminants had not the same impact on microparasite occurrence. Metals enhanced the infection, except zinc associated only with higher prevalence of the commensal ciliate Conchophthirus acuminatus. We should note that Rickettsiales-like organism infection is higher at higher Ni and Cr concentrations. Models indicated also that the most polluted sites were also those with higher rates of co-infections. Therefore, the continuous contamination of freshwater ecosystems implies a significant risk promoting the development of parasites that may affect bivalve populations and other species belonging to their life-cycle.

Minguez L; Devin S; Molloy DP; Guérold F; Giambérini L

2013-05-01

393

Zebra mussel (Dreissena polymorpha) parasites: potentially useful bioindicators of freshwater quality?  

UK PubMed Central (United Kingdom)

In environmental quality bioassessment studies, analysis of host-parasite interactions may well be a valuable alternative to classical macroinvertebrate sampling approaches. Herein, we investigated whether zebra mussel (Dreissena polymorpha) parasites could be useful biomonitoring tools. Mussel populations were sampled twice at two sites in northeastern France representing different levels of contamination and were characterized for parasite infection following standard histological methods. Our results indicated that sites of different environmental quality (i.e. chemical contamination) exhibited different parasite communities characterized by different trematode species and parasite associations. An additional significant finding was the positive correlation established between the prevalence of Rickettsiales-like organisms and metal contamination. Multivariate analyses were valuable in examining parasite communities.

Minguez L; Molloy DP; Guérold F; Giambérini L

2011-01-01

394

Evaluation of several priority pollutants in zebra mussels (Dreissena polymorpha) in the largest Italian subalpine lakes.  

UK PubMed Central (United Kingdom)

Zebra mussel (Dreissena polymorpha) has been used for the biomonitoring of several POPs (PCBs, DDTs, HCB and HCHs) in the largest Italian subalpine great lakes (Lake Maggiore, Garda, Como, Iseo and Lugano). Samplings were carried out in April 2003 at 15 locations selected according to industrial and anthropic levels of lakes. Results have pointed out high DDT levels in D. polymorpha specimens from Lake Maggiore (700-1400 ng/g lipids, 5-9 times higher than those measured in mussels of other Italian lakes), due to a contamination from a chemical plant located on one of the main lake inlet that occurred in 1996. On the contrary, PCB levels (400-2509 ng/g lipids) highlighted an overall pollution, with some sporadic peaks of contamination. Data showed a moderate increase trend compared to those found in a previous monitoring campaign carried out in 1996. Future monitoring is needed in order to confirm this tendency.

Riva C; Binelli A; Provini A

2008-02-01

395

Evaluation of several priority pollutants in zebra mussels (Dreissena polymorpha) in the largest Italian subalpine lakes.  

Science.gov (United States)

Zebra mussel (Dreissena polymorpha) has been used for the biomonitoring of several POPs (PCBs, DDTs, HCB and HCHs) in the largest Italian subalpine great lakes (Lake Maggiore, Garda, Como, Iseo and Lugano). Samplings were carried out in April 2003 at 15 locations selected according to industrial and anthropic levels of lakes. Results have pointed out high DDT levels in D. polymorpha specimens from Lake Maggiore (700-1400 ng/g lipids, 5-9 times higher than those measured in mussels of other Italian lakes), due to a contamination from a chemical plant located on one of the main lake inlet that occurred in 1996. On the contrary, PCB levels (400-2509 ng/g lipids) highlighted an overall pollution, with some sporadic peaks of contamination. Data showed a moderate increase trend compared to those found in a previous monitoring campaign carried out in 1996. Future monitoring is needed in order to confirm this tendency. PMID:17561323

Riva, Consuelo; Binelli, Andrea; Provini, Alfredo

2007-06-11

396

A light- and electron microscopic study of primordial germ cells in the zebra fish (Danio rerio)  

Directory of Open Access Journals (Sweden)

Full Text Available In sexually reproducing organisms, primordial germ cells (PGCs) give rise to the cells of the germ line, the gametes. In many animals, PGCs are set apart from somatic cells early during embryogenesis. This study explores the origin of primordial germ cells (PGCs) of the zebra fish and examines their morphology during early development (1st day-15th day). PGCs were selectively stained by the alkaline phosphatase histochemical reaction and viewed by light and electron microscopy from the time they are first detectable in the yolk sac endoderm. PGCs occurred in the subendodermal space on the syncytial periblast; differing from the surrounding endodermal cells. Later the PGCs moved to between the blastoderm and yolk sac and transferred to the dorsal mesentery where they formed gonadal anlage with mesoderm cells. PGCs were easily distinguished from somatic cells by their morphology and low electron density of their nuclei. Under light microscopy, PCGs were rounded with a distinct cytoplasmic membrane.

Nazan Deniz Koç; Rikap Yüce

2012-01-01

397

Integral capture cross section measurements of americium isotopes in the ZEBRA reactor at Winfrith  

International Nuclear Information System (INIS)

[en] Samples of 241Am and 243Am were irradiated in the ZEBRA reactor at Winfrith in typical power fast reactor spectra, including a mockup of PFR. The capture cross section measurement of 241Am is described in which the composition of the core, and therefore the neutron spectrum in which the irradiations took place, was a close mockup to that of a power fast reactor. The curium produced in the irradiation was separated by radiochemical techniques and estimated qualitatively and quantitatively by use of alpha counting and alpha spectrometry techniques. The partial capture cross section for the production of 242Cm from 241Am was found to be 1.50 +- 0.09/barns

1978-11-22

398

In situ growth of juvenile zebra mussels in a regulated stream  

Science.gov (United States)

We investigated the in situ growth of juvenile zebra mussels (Dreissena polymorpha) in a reach of the Huron River (southeast Michigan) below a dam with a control gate that regulates water levels. Growth was significantly different among sample dates over a five-month-long monitoring season. Mean growth of mussels generally decreased from 0.093 mm/day just above the dam to 0.067 mm/day 4 km downstream, then increased to 0.091 mm/day at end of the 17-km-long study area. Significant differences among sites were most numerous in August during a severe drought when discharges fell substantially. Growth was positively correlated with discharges (R2 = 0.94, p a levels in the study area, however, was weak (R2 = 0.69, p < 0.1). Our study suggests that discharge may be one controlling factor for dreissenid populations in small streams.

French, John R. P., III; Nichols, S. Jerrine; Craig, Jaquelyn M.; Allen, Jeffery D.; Black, M. Glen

2006-01-01

399

The basic unit of the imaging plane of the ZEBRA low energy gamma ray telescope  

International Nuclear Information System (INIS)

[en] The mechanical, electrical, and performance characteristics of one element of the ZEBRA telescope's position sensitive detection plane are presented. One unit comprises a NaI (T1) bar 55 x 5, 8 x 5 cm thick and two photomultiplier tubes one mounted on each end. The surface of the bar has been treated to enhance the exponential attenuation of the scintillation light produced by an event. The signal from the two tubes are taken in coincidence and, by the application of two simple algorithms, the energy and position of the event along the bar can be calculated. The tubes are powered by two programmable low consumption high tension supplies. Their digital control makes automatic gain correction feasible during the flight

1986-01-01

400

On the interpretation of the polarized zebra-structure in the solar radiowave radiation  

International Nuclear Information System (INIS)

[en] The conditions of the generation of solar polarized radio emission with bands in the dynamic spectrum (zebra-structure) are investigated. Two possible variants are considered. In the first variant radio emission excitation is explained by cyclotron instability in the small size source of Bernstein modes and plasma waves in the upper hybrid resonance frequency with their subsequent merging into electromagnetic radiation. The polarization effect appears only if Bernstein modes being non-longitudinal are taken into account. The polarization character is determined by the magnetic field orientation in the source relative to the direction to the Earth. In the second variant the radio emission generation occurs in the distributed ununiform source. The polarization appears when the high level of excited plasma waves ensures the substantial role of the induced scattering

1977-01-01

 
 
 
 
401

Effect of current prepulse on wire array initiation on the 1-MA ZEBRA accelerator  

International Nuclear Information System (INIS)

[en] Experiments on the 1-MA ZEBRA accelerator with reduced current prepulse duration, using a flashover switch, demonstrate a significant increase of initial energy deposition into the tungsten wire array before breakdown, and of total radiation energy from the Z pinch. Shorter current prepulse raises the current rate through each individual wire in the array and results in an increase of the energy deposition into wire cores before breakdown. In our experiments, the inferred tungsten wire temperature increases from ?800 K (with 250 ns prepulse) up to ?3700 K (with 60 ns prepulse). Total radiation energy increases from 12 to 16 kJ. Our experimental results relate wire-array initiation to heating of the individual array wires up to the time of breakdown

2007-01-01

402

Increased mortality in a colony of zebra finches exposed to continuous light.  

UK PubMed Central (United Kingdom)

Over a 1-mo period, increased morbidity and mortality occurred in a flock of zebra finches (Taeniopygia guttata). Complete postmortem examination was performed on 6 of the affected birds, 4 of which subsequently were diagnosed with the avian gastric yeast previously known as megabacteriosis (Macrorhabdus ornithogaster). The remaining 2 birds were diagnosed with a cloacal abscess and with large bowel perforation and peritonitis. All the birds had been prophylactically treated with amphotericin B for megabacteria 2 mo previously. An environmental assessment revealed that the light cycle had been altered, and the birds were being exposed to constant light. With correction of the light cycle, the health of the birds improved dramatically. The remaining birds were treated again with amphotericin B, and baseline mortality returned to normal. The birds in this report show several similarities to previous reports of sleep deprivation syndrome in mammals.

Snyder JM; Molk DM; Treuting PM

2013-01-01

403

Automatic data analysis of real-time song and locomotor activity in zebra finches.  

UK PubMed Central (United Kingdom)

The zebra finch is a superb natural animal model to study cognition and as such could contribute to the further understanding of nicotinic intervention therapies for patients suffering from cognitive impairment as observed in neurodegenerative disorders. Manual analysis of data produced by this model is extremely labour intensive, error-prone, and typically takes weeks to complete. We designed data acquisition methods, selected analysis algorithms, and developed software to efficiently and accurately automate the detection and classification of song production (cognitive functioning) and locomotor activity (physical condition). Our custom-designed software accurately classifies song and locomotor activities. After classification, the reduced data sets can be further analysed with popular tools, such as 'R'.

Cappendijk SL; Miller GL; Yount PL; Engelen RA

2013-01-01

404

Worths and interactions of simulated fast breeder reactor control rods in ZEBRA and SNEAK assemblies  

International Nuclear Information System (INIS)

[en] Measurements of the worths of simulated control rods for fast power reactors have been made in the ZEBRA and SNEAK critical assemblies by the modified source multiplication method (MSMM). The assemblies used were the conventional and unconventional core arrangements from the BIZET program and a compacted version of a conventional core. The control rods were mainly natural B4C, with some study of 40% 10B-enriched B4C and of Eu2O3. Correction factors for the MSMM were obtained from eigenvalue and source-mode diffusion theory calculations in XY geometry. The measured rod worths and interactions are compared with calculated values from methods and data similar to those used by the different participants in the BIZET program to predict the corresponding parameters in fast power reactors. In general, acceptable agreement is found