WorldWideScience
1

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

OpenAIRE

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 a...

Grobler, J. H.

1983-01-01

2

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

OpenAIRE

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 a...

Grobler, J. H.

1983-01-01

3

Comparative genetics of sarcoid tumour-affected and non-affected mountain zebra (Equus zebra) populations  

OpenAIRE

In recent years, South African conservation officials have noted the appearance of sarcoid tumour-like growths in Cape mountain zebra (Equus zebra zebra) populations. In domestic horses (Equus ferus caballus), a genetic predisposition for this bovine papillomavirusinduced tumour is reported. This investigation compared population genetic parameters within tumour-affected populations in Bontebok National Park and Gariep Dam Nature Reserve against Cape mountain zebra populations ...

Sasidharan, Sooryakanth P.; Ludwig, Anette; Harper, Cindy Kim; Moodley, Yoshan; Bertschinger, H. J.; Guthrie, Alan John

2011-01-01

4

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

OpenAIRE

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.

Penzhorn, B. L.

1982-01-01

5

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

OpenAIRE

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.

Penzhorn, B. L.

1982-01-01

6

Detection and characterization of papillomavirus in zebra (Equus zebra) and other South African wildlife species  

OpenAIRE

Sarcoid-like tumours have been reported in Cape mountain zebra (Equus zebra zebra) in two South African game parks recently. These tumours caused severe distress to the animals and also made them unsightly for tourists visiting the parks. The aim of this investigation was to identify and characterize the infectious agent considered to be involved in the aetiology of sarcoid in the Cape mountain zebra. Bovine papillomaviruses (BPV) -1 and -2 deoxyribonucleic acid (DNA) we...

Dyk, Enette

2011-01-01

7

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

OpenAIRE

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,...

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

2007-01-01

8

A study of sarcoid tumours in Cape Mountain Zebra (Equus zebra zebra)  

OpenAIRE

The Cape Mountain Zebra (CMZ) has been described as one of the most vulnerable mammals in the Republic of South Africa with current populations existing in isolated units. In recent years, South African conservation officials have noted the appearance of tumour like growths, similar to equine sarcoids, in some of these populations. The possibility that the existing populations, numbering around 1 500 animals in total, arose from a very small gene pool is very real, considering that in the ear...

Marais, Johan

2008-01-01

9

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

OpenAIRE

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 piro...

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

2009-01-01

10

Basis for the photoidentification of zebras (Equus burchellii in the National Zoological Garden of Cuba  

Directory of Open Access Journals (Sweden)

Full Text Available Variability in facial strip patterns in zebras aloud its individualization. This is the basis for photo identification techniques that substitute traditional marking methods that can be expensive and traumatic. Current paper present an identification key of Equus burchelli captive in the National Zoological Garden of Cuba using left side pictures of their faces. Region of interest was limited by axes traced from posterior mouth edge, the eye and the lower base of neck. Strips crossing each ax were counted building a numerical code for each individual. The 68 % of captive zebras (54 individuals were photo identified. A group of 12 individuals had a code completely different from others, identifying each one. Remaining individuals could be grouped by similar codes, resulting in 11 pairs, and four groups of three, four, five and six individuals each. Every individual was characterized by the occurrence of spots, truncated strips, bridges between vertical stripes, periorbital bands, and bifurcated stripes. With all this characters a visual identification key was developed.

Ernesto Testé Lozano

2013-09-01

11

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.

N.E. Collins

2012-05-01

12

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

Scientific Electronic Library Online (English)

Full Text Available SciELO South Africa | Language: English Abstract in english A 10-year-old tame zebra gelding was presented after sufferingfrom 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 haema [...] tology 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.

13

Prevalence of theileria equi and babesia caballi as well as the identification of associated ticks in sympatric grevy's zebras (equus grevyi) and donkeys (equus africanus asinus) in northern kenya.  

Science.gov (United States)

Abstract The role of equine piroplasmosis as a factor in the population decline of the Grevy's zebra is not known. We determined the prevalence of Babesia caballi and Theileria equi in cograzing Grevy's zebras (Equus grevyi) and donkeys (Equus africanus asinus) in northern Kenya and identified the associated tick vectors. Blood samples were taken from 71 donkeys and 16 Grevy's zebras from March to May 2011. A nested PCR reaction using 18s ribosomal (r)RNA primers on 87 blood spots showed 72% (51/71; 95% confidence interval [CI] 60.4-81.0%) of donkeys and 100% (16/16; 95% CI, 77.3-100%) of Grevy's zebras were T. equi positive. No samples were positive for B. caballi. Sequence comparison using the National Center for Biotechnology Information's basic local alignment search tool identified homologous 18s rRNA sequences with a global geographic spread. The T. equi-derived sequences were evaluated using Bayesian approaches with independent Metropolis-coupled Markov chain Monte Carlo runs. The sequences clustered with those found in Sudan, Croatia, Mongolia, and the US, with statistical support greater than 80% for the two main clades. Hyalomma tick species were found on both donkeys and Grevy's zebras, whereas Rhipicephalus pulchellus was found exclusively on Grevy's zebras and Hyalomma marginatum rupfipes on donkeys. The prevalence of T. equi was 100% in Grevy's zebras and 72% in donkeys with common tick vectors identified. Our results suggest that donkeys and Grevy's zebras can be asymptomatic carriers and that piroplasmosis is endemic in the study area. PMID:25380362

Hawkins, Elaine; Kock, Richard; McKeever, Declan; Gakuya, Francis; Musyoki, Charles; Chege, Stephen M; Mutinda, Mathew; Kariuki, Edward; Davidson, Zeke; Low, Belinda; Skilton, Robert A; Njahira, Moses N; Wamalwa, Mark; Maina, Elsie

2015-01-01

14

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

OpenAIRE

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 piro...

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

2012-01-01

15

Shedding of Clostridium difficile PCR ribotype 078 by zoo animals, and report of an unstable metronidazole-resistant isolate from a zebra foal (Equus quagga burchellii).  

Science.gov (United States)

Clostridium difficile is an emerging and potentially zoonotic pathogen, but its prevalence in most animal species, including exhibition animals, is currently unknown. In this study we assessed the prevalence of faecal shedding of C. difficile by zoo animals, and determined the ribotype, toxin profile and antimicrobial susceptibility of recovered isolates. A total of 200 samples from 40 animal species (36.5% of which came from plains zebra, Equus quagga burchellii) were analysed. C. difficile was isolated from 7 samples (3.5% of total), which came from the following animal species: chimpanzee (Pan troglodytes troglodytes), dwarf goat (Capra hircus), and Iberian ibex (Capra pyrenaica hispanica), with one positive sample each; and plains zebra, with 4 positive samples from 3 different individuals. Most recovered isolates (4/7, 57.1%) belonged to the epidemic PCR ribotype 078, produced toxins A and B, and had the genes encoding binary toxin (i.e. A(+)B(+)CDT(+) isolates). The remaining three isolates belonged to PCR ribotypes 039 (A(-)B(-)CDT(-)), 042 (A(+)B(+)CDT(-)) and 110 (A(-)B(+)CDT(-)). Regardless of their ribotype, all isolates displayed high-level resistance to the fluoroquinolones ciprofloxacin, enrofloxacin and levofloxacin. Some isolates were also resistant to meropenem and/or ertapenem. A ribotype 078 isolate recovered from a male zebra foal initially showed in vitro resistance to metronidazole (MIC ? 256 ?g/ml), but lost that trait after subculturing on non-selective media. We conclude that zoo animals belonging to different species can carry ribotype 078 and other toxigenic strains of C. difficile showing resistance to antimicrobial compounds commonly used in veterinary and/or human medicine. PMID:24467928

Álvarez-Pérez, Sergio; Blanco, José L; Martínez-Nevado, Eva; Peláez, Teresa; Harmanus, Celine; Kuijper, Ed; García, Marta E

2014-03-14

16

Recent data on zebra patterns  

Science.gov (United States)

A comparative analysis of two recent solar radio outbursts around 3 GHz with zebra structures and fiber bursts in their dynamical radio spectra is carried out using all available ground-based and satellite data (SOHO, TRACE, RHESSI). The latest theoretical models of the zebra pattern are critically discussed. New data on microwave zebra structures and fiber bursts suggests that they are analogous to similar structures observed at meter wavelengths. It was discovered that in the 2,6-3,8 GHz frequency band more than 34 zebra stripes can appear simultaneously, and some isolated fiber bursts can continuously be transformed into zebra stripes. This fact indicates a single origin for both structures. The zebra pattern was observed when the signs of magnetic reconnections were revealed in images of 195 Å UV lines, and radio sources coincided with positions of some new sources in hard X-rays. All the main properties of the stripes in emission and absorption can be explained if they are associated with interactions between electrostatic plasma waves and whistlers, taking into account the quasi-linear diffusion of fast particles with the loss-cone distribution on whistlers. In this model it is possible to obtain realistic values for the magnetic field strength of B ? 160~G at the plasma level of about 3 GHz. The double plasma resonance model for the zebra pattern based on the known realistic dependences of electron density and magnetic field yields a frequency dependence for the frequency separation between stripes that does not agree with the observations.

Chernov, G. P.; Yan, Y. H.; Fu, Q. J.; Tan, Ch. M.

2005-07-01

17

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

OpenAIRE

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 e...

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

2013-01-01

18

Zebra-User's Guide and Reference  

OpenAIRE

Zebra is a free, fast, friendly information management system. It can index records in XML/SGML, MARC, e-mail archives and many other formats, and quickly find them using a combination of boolean searching and relevance ranking. Search-and-retrieve applications can be written using APIs in a wide variety of languages, communicating with the Zebra server using industry-standard information-retrieval protocols. This manual explains how to build and install Zebra, configure it appropriately f...

Hammer, Sebastian; Dickmeiss, Adam; Levanto, Heikki; Taylor, Mike

2005-01-01

19

Zebra-percolation on Cayley trees  

OpenAIRE

We consider Bernoulli (bond) percolation with parameter $p$ on the Cayley tree of order $k$. We introduce the notion of zebra-percolation that is percolation by paths of alternating open and closed edges. In contrast with standard percolation with critical threshold at $p_c= 1/k$, we show that zebra-percolation occurs between two critical values $p_{{\\rm c},1}$ and $p_{{\\rm c},2}$ (explicitly given). We provide the specific formula of zebra-percolation function.

Gandolfo, D.; Rozikov, U. A.; Ruiz, J.

2013-01-01

20

ZEBRA battery meets USABC goals  

Science.gov (United States)

In 1990, the California Air Resources Board has established a mandate to introduce electric vehicles in order to improve air quality in Los Angeles and other capitals. The United States Advanced Battery Consortium has been formed by the big car companies, Electric Power Research Institute (EPRI) and the Department of Energy in order to establish the requirements on EV-batteries and to support battery development. The ZEBRA battery system is a candidate to power future electric vehicles. Not only because its energy density is three-fold that of lead acid batteries (50% more than NiMH) but also because of all the other EV requirements such as power density, no maintenance, summer and winter operation, safety, failure tolerance and low cost potential are fulfilled. The electrode material is plain salt and nickel in combination with a ceramic electrolyte. The cell voltage is 2.58 V and the capacity of a standard cell is 32 Ah. Some hundred cells are connected in series and parallel to form a battery with about 300 V OCV. The battery system including battery controller, main circuit-breaker and cooling system is engineered for vehicle integration and ready to be mounted in a vehicle [J. Gaub, A. van Zyl, Mercedes-Benz Electric Vehicles with ZEBRA Batteries, EVS-14, Orlando, FL, Dec. 1997]. The background of these features are described.

Dustmann, Cord-H.

21

Introduced species, zebra mussels in North America  

Science.gov (United States)

The discovery of zebra mussels in North America in 1988 raised concern for water users because the species became abundant enough to obstruct the flow of water in human-made structures such as pipes and screens. This work reviews the biology, distribution, and impacts of zebra mussels in the context of its discovery in the Laurentian Great Lakes and its impending spread to most surface waters of North America.

Schloesser, Don W.

1995-01-01

22

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

OpenAIRE

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. Moreover, EBV latency can also be disrupted by phorbol esters, which act, in part, through AP-1 activators. It is not known whether ZEBRA and AP-1 factors play equivalent roles in the initial stages of re...

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

1996-01-01

23

Safeguards sealing systems for Zebra  

International Nuclear Information System (INIS)

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)

24

On the origin of microwave zebra pattern  

Science.gov (United States)

The results of the first observations of a zebra pattern at frequencies around5.6GHz are presented. The fine structures in the emission spectrum were recorded simultaneously by the Siberian Solar Radiotelescope and the spectropolarimeters of the National Astronomical Observatories, which allowed us to study the presented event with high spatial, temporal and spectral resolution. The apparent source size does not exceed10arcsec, and the sources of the different stripes of the zebra structure coincide spatially. The circular polarization degree reaches 100%, and the polarization sense corresponds to the extraordinary wave. We argue that the most probable generation mechanism of the zebra pattern is nonlinear coupling of Bernstein waves. In this case the value of the magnetic field in the burst source, determined by the frequency separation between the adjacent stripes, is 60 80 G.

Altyntsev, A. T.; Kuznetsov, A. A.; Meshalkina, N. S.; Rudenko, G. V.; Yan, Yihua

2005-03-01

25

Are Zebra Carbonates Formed During Seismic Events?  

Science.gov (United States)

Zebra carbonates are characterized by subparallel, rhythmic, mm-scale banding of host rock and vein. Their genesis has been interpreted by different authors as primary sedimentary structure, metasomatic infiltration or mechanical fragmentation followed by deposition of vein minerals. We studied zebra carbonates in the damage zones of normal faults formed during the drainage of an overpressure cell at about 7 km depth, in outcrops on Jebel Shams, Oman Mountains. They show a distinct pattern of mm-scale regularly spaced calcite veins in the dark grey, fine-grained carbonate host rocks, often connected laterally to a wide mode I fracture filled by a single calcite vein several cm thick. Veins in the zebra carbonates are filled with blocky crystals, indicating that the fractures remained open after their formation to allow crystal growth from a supersaturated fluid. Microstructures show no evidence of repeated crack-seal events and we conclude that all the veins in one zebra were formed simultaneously. The very high density of closely-spaced and simultaneously formed fractures indicates that they were formed very rapid loading, producing fracture densities much higher than expected during slow deformation. On the other hand, the high- density fracture systems formed during explosive fracturing in dry rocks are much less regularly spaced. We hypothesize that the zebra carbonates were formed by rapid loading during faulting in highly overpressured carbonates, in places where coseismic rupture leads to a significant fluid pressure drop in dilatant jogs. The permeability of the matrix carbonate leads to drop in pore-fluid pressure close to the crack walls. This makes the host rock stronger close to the crack wall, so that the next fracture will preferentially propagate into the matrix away from the walls of the existing fracture. This process can lead to a more regularly spaced pattern of veins. Further work on zebra carbonates could provide a new tool to distinguish seismic from aseismic faults in carbonates.

Urai, J. L.; Holland, M.; Schoenherr, J.; Miller, S.

2006-12-01

26

Pattern of faecal 20-oxopregnane and oestrogen concentrations during pregnancy in wild plain zebra mares  

OpenAIRE

Regulative endocrine mechanisms influence the reproductive behaviour and success of mammals, but they have been studied predominantly in domestic and captive animals. The study aims at describing the pattern of faecal 20-oxopregnane and oestrogen concentrations during pregnancy in wild plains zebra Equus quagga chapmani. Data were collected during wet and dry seasons 2007–2009. Enzyme Immunoassays were used to determine 20-oxopregnane and oestrogen concentrations in faecal sampl...

Ncube, Hlengisizwe; Duncan, Patrick; Grange, Sophie; Cameron, Elissa Z.; Barnier, Florian; Ganswindt, Andre

2011-01-01

27

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)

28

Motion camouflage induced by zebra stripes.  

Science.gov (United States)

The functional significance of the zebra coat stripe pattern is one of the oldest questions in evolutionary biology, having troubled scientists ever since Charles Darwin and Alfred Russel Wallace first disagreed on the subject. While different theories have been put forward to address this question, the idea that the stripes act to confuse or 'dazzle' observers remains one of the most plausible. However, the specific mechanisms by which this may operate have not been investigated in detail. In this paper, we investigate how motion of the zebra's high contrast stripes creates visual effects that may act as a form of motion camouflage. We simulated a biologically motivated motion detection algorithm to analyse motion signals generated by different areas on a zebra's body during displacements of their retinal images. Our simulations demonstrate that the motion signals that these coat patterns generate could be a highly misleading source of information. We suggest that the observer's visual system is flooded with erroneous motion signals that correspond to two well-known visual illusions: (i) the wagon-wheel effect (perceived motion inversion due to spatiotemporal aliasing); and (ii) the barber-pole illusion (misperceived direction of motion due to the aperture effect), and predict that these two illusory effects act together to confuse biting insects approaching from the air, or possibly mammalian predators during the hunt, particularly when two or more zebras are observed moving together as a herd. PMID:24368147

How, Martin J; Zanker, Johannes M

2014-06-01

29

Dynamics of zebra finch and mockingbird vocalizations  

Science.gov (United States)

Along with humans, whales, and bats, three groups of birds which include songbirds (oscines) such as the Zebra Finch (Taeniopygia guttata) and Mockingbird (Mimus polyglottos) are the only creatures known to learn sounds by imitation. Numerous similarities between human and songbird vocalizations exist and, recently, it has been shown that Zebra Finch in particular possesses a gene, FoxP2, known to be involved in human language. This thesis investigates song development in Zebra Finches, as well as the temporal dynamics of song in Mockingbirds. Zebra Finches have long been the system of choice for studying vocal development, ontogeny, and complexity in birdsong. Physicists find them intriguing because the spectrally complex vocalizations of the Zebra Finch can exhibit sudden transitions to chaotic dynamics, period doubling & mode-locking phenomena. Mockingbirds, by contrast, provide an ideal system to examine the richness of an avian repertoire, since these musically versatile songbirds typically know upwards of 200 songs. To analyse birdsong data, we have developed a novel clustering algorithm that can be applied to the bird's syllables, tracing their dynamics back to the earliest stages of vocal development. To characterize birdsong we have used Fourier techniques, based upon multitaper spectral analysis, to optimally work around the constraints imposed by (Heisenberg's) time-frequency uncertainty principle. Furthermore, estimates that provide optimal compromise between frequency and temporal resolution have beautiful connections with solutions to the Helmholtz wave equation in prolate spheroidal coordinates. We have used this connection to provide firm foundation for certain heuristics used in the literature to compute associated spectral derivatives and supply a pedagogical account here in this thesis. They are of interest because spectral derivatives emphasize sudden changes in the dynamics of the underlying phenomenon, and often provide a nice way to visualize such dynamics. Our Zebra Finch data consist of continuous recordings of six tutored birds from the early, plastic stages of sound production to the development of fully crystallized mature song. Our analysis reveals that well before the Zebra Finch hears adult song, identifiably distinct clusters are observable for all birds in the same regions of feature space. (Abstract shortened by UMI.)

Cimenser, Aylin

30

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

31

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

32

The zebra finch neuropeptidome: prediction, detection and expression  

OpenAIRE

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 f...

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

2010-01-01

33

Zebra finch cell lines from naturally occurring tumors  

OpenAIRE

The zebra finch (Taeniopygia guttata) has been intensively studied in many research fields including neuroscience, behavioral neurobiology, and evolution of the genome. Although numerous molecular and genomic resources are available for this model species, immortalized cell lines have been lacking. We have established two zebra finch cell lines derived from spontaneous tumors. ZFTMA is a tetraploid female cell line and G266 as a diploid male cell line. These first zebra finch cell lines shoul...

Itoh, Yuichiro; Arnold, Arthur P.

2011-01-01

34

Prevalence of antibodies against some equine viruses in zebra (Zebra burchelli) in the Kruger National Park, 1991-1992  

OpenAIRE

The presence of antibodies against equine encephalosis virus (EEV) and equid herpesvirus 1 and 4 in zebra in the Kruger National Park (KNP) was demonstrated. The ability of zebra to maintain immunity against EEV is illustrated by the appearance of neutralizing antibodies in most zebra foals within months of losing their maternal immunity. This occurs in every month of the year, even in winter. The high proportion of serologically positive foals in winter is ascribed to the presenc...

Barnard, B. J. H.; Paweska, J. T.

1993-01-01

35

Inter-birth interval in zebras is longer following the birth of male foals than after female foals  

OpenAIRE

Mammalian reproductive rates vary among individuals for physiological and environmental reasons. This study aims to determine reproductive rates from an individually monitored population of wild Plains zebras Equus quagga, and to assess the sources of variability in inter-birth intervals. The animals were monitored, where possible, every six months from 2004 to 2011. Thirty nine intervals corresponding to 65 births in 26 mares were identified, using direct observations and faecal steroid moni...

Barnier, Florian; Grange, Sophie; Ganswindt, Andre; Ncube, Hlengisizwe; Duncan, Patrick

2012-01-01

36

The Zebra Multi-Chamber Scanning System  

International Nuclear Information System (INIS)

The Multi-Chamber Scanning System developed for the zero-power fast reactor Zebra comprises an integral array of 150 parallel-plate fission chambers loaded into fuel elements in a similar manner to standard core components. The chamber outputs are counted sequentially under computer control to provide a rapid three-dimensional power mapping facility. The report describes the basic concept, design and calibration of the fission chambers, design of the electronics and computer interface, and overall system performance as exemplified by measurements on a mock-up of the core of the Prototype Past Reactor. (author)

37

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

38

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.

39

Etude structurale et fonctionnelle du complexe ZEBRA / ADN méthylé  

OpenAIRE

Le virus Epstein-Barr (EBV) est un ?-Herpesvirus infectant plus de 95 % de la population mondiale. Le facteur de transcription viral ZEBRA est responsable de la transition entre phases latentes et lytiques du virus. ZEBRA est une protéine de la famille des protéines bZIP. Elle active les promoteurs des gènes lytiques de l'EBV en se fixant sur des sites ADN spécifiques appelés sites ZREs. ZEBRA fixe préférentiellement certains sites ZREs lorsqu'ils sont méthylés sur leurs motifs CpG ...

Pagniez, Priscilla

2008-01-01

40

Karyotypic polymorphism of the zebra finch Z chromosome  

OpenAIRE

We describe a karyotypic polymorphism on the zebra finch Z chromosome. This polymorphism was discovered because of a difference in the position of the centromere and because it occurs at varying frequencies in domesticated colonies in the USA and Germany and among two zebra finch subspecies. Using DNA fluorescent in situ hybridization to map specific Z genes and measurements of DNA replication, we show that this polymorphism is the result of a large pericentric inversion involving the majorit...

Itoh, Yuichiro; Kampf, Kathy; Balakrishnan, Christopher N.; Arnold, Arthur P.

2011-01-01

41

A Minimally-Invasive Procedure for Sexing Young Zebra Finches  

OpenAIRE

Zebra finches have been widely used to study neurobiology underlying vocal development. Because only male zebra finches learn song, efficient developmental use of these animals requires early determination of sex at ages that precede maturation of secondary sex characteristics. We have developed a sex determination method that combines a forensics method of genomic DNA isolation (from very small blood samples) with PCR amplification from Z and W sex chromosomes (males are ZZ, females ZW). Thi...

Soderstrom, Ken; Qin, Weixi; Leggett, Matthew H.

2007-01-01

42

Radioheliograph observations of microwave bursts with zebra structures  

OpenAIRE

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...

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

2011-01-01

43

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

44

Viral proteins associated with the Epstein-Barr virus transactivator, ZEBRA.  

OpenAIRE

The BamHI Z Epstein-Barr replication activator (ZEBRA) mediates disruption of latency and induction of Epstein-Barr virus (EBV) early gene expression in latently infected lymphocytes. Polyclonal rabbit sera raised against ZEBRA were used to immunoprecipitate ZEBRA-associated proteins (ZAPs). ZAPs of 19, 21, 23, and 42 kDa were coimmunoprecipitated with ZEBRA from extracts of EBV-producing lymphoid cell lines. ZAPs were not recognized directly by the rabbit sera, but they were antigenic for EB...

Katz, D. A.; Baumann, R. P.; Sun, R.; Kolman, J. L.; Taylor, N.; Miller, G.

1992-01-01

45

Activation domain requirements for disruption of Epstein-Barr virus latency by ZEBRA.  

OpenAIRE

Latent infection of B lymphocytes by Epstein-Barr virus (EBV) can be disrupted by expression of the EBV ZEBRA protein. ZEBRA, a transcriptional activator, initiates the EBV lytic cascade by activating viral gene expression. ZEBRA is also indispensable for viral replication and binds directly to the EBV lytic origin of replication. The studies described herein demonstrate that the activation domain. ZEBRA activation can be replaced by a heterologous acidic, proline-rich, or glutamine-rich acti...

Askovic?, S.; Baumann, R.

1997-01-01

46

The Zurich Extragalactic Bayesian Redshift Analyzer (ZEBRA), version 1.0 -- User manual  

OpenAIRE

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...

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

2008-01-01

47

Chromeless Phase Lithography Using Scattering Bars and Zebra Patterns  

Science.gov (United States)

Resolution enhancement technology refers to a technique that extends the usable resolution of an imaging system without decreasing the wavelength of light or increasing the numerical aperture (NA) of the imaging tool. Off-axis illumination and a phase shift mask (PSM) are essentially accompanied by optical proximity correction (OPC) for most devices nowadays. Chromeless phase lithography (CPL) is one of the PSM technologies. To obtain the best resolution, proper OPC is required with CPL. While the most common application of OPC is to provide mask bias, an additional technique is the use of scattering bars (SBs) and zebra patterns. We compared zebra patterns for 65 nm lines and spaces (L/S) and 45 nm isolated line (I/L) with SBs. To optimize zebra pattern density, we vary the line width and pitch of the zebra patterns. We confirmed that the use of SB and zebra patterns could realize the target linewidth and control necessary for acheiving dense L/S and I/L.

Kang, Hye-Young; An, Ilsin; Shin, Dong-Soo; Jeong, HeeJun; Ahn, Chang-Nam; Oh, Hye-Keun

2006-11-01

48

Mechanisms of copying behaviour in zebra finches.  

Science.gov (United States)

When an individual is faced with choosing between unfamiliar food options, it may benefit initially by choosing the option chosen by other animals so avoiding potentially poisonous food. It is not clear which cues the naïve forager learns from the demonstrator for choosing between food options. To determine firstly which birds (zebra finches, Taeniopygia guttata) would copy a demonstrator's choice, in Experiment 1 we presented each observer with a demonstrator feeding from one of two differently coloured feeders and then tested the observer's feeder colour preference. Of the same-sex/mixed-sex demonstrator-observer pairs tested only females copied male demonstrators. In Experiment 2, birds did not prefer either feeder colour in the absence of demonstrators confirming the social learning effect observed in Experiment 1. In Experiment 3, copying females fed significantly more at the feeder of the demonstrated colour, rather than at the location of the demonstrated feeder. These data point not just to the identity of the individual to be copied but also to the kind of information learned. PMID:25444776

Guillette, Lauren M; Healy, Susan D

2014-10-01

49

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 for such 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 use an evaluation approach for web search engines for rare disease diagnosis which includes 56 real life diagnostic cases, state-of-the-art evaluation measures, and curated information resources. 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 outperformsGoogle Search in both default setup 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 web search engines. The proposed evaluation approach can be valuable for future development and benchmarking. The FindZebra search engine is available at http://www.findzebra.com/.

Dragusin, Radu; Petcu, Paula

2013-01-01

50

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

51

Activation of the Epstein-Barr virus BMRF1 and BZLF1 promoters by ZEBRA in Saccharomyces cerevisiae.  

OpenAIRE

ZEBRA has been shown to activate model reporter genes consisting of synthetic oligomerized ZEBRA response elements upstream of a minimal CYC1 promoter fused to beta-galactosidase in the yeast Saccharomyces cerevisiae. Here it is shown that in S. cerevisiae ZEBRA activates transcription of natural Epstein-Barr virus promoters. Two Epstein-Barr virus promoters were shown to be activated by ZEBRA in S. cerevisiae: Zp, the promoter that regulates expression of BZLF1, which encodes ZEBRA; and EAp,...

Countryman, J. K.; Heston, L.; Gradoville, L.; Himmelfarb, H.; Serdy, S.; Miller, G.

1994-01-01

52

A possible interpretation of the zebra pattern in solar radiation  

Science.gov (United States)

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.

Fomichev, V. V.; Fainshtein, S. M.; Chernov, G. P.

2009-12-01

53

Potato psyllid vector density and zebra chip disease  

Science.gov (United States)

Zebra chip disease (ZC), which is caused by ‘Candidatus Liberibacter solanacearum’ (Lso) and vectored by potato psyllids Bactericera cockerelli, is a continuing threat to the North American potato industry. Current management entails frequent insecticide sprays for the vectors as thresholds for spra...

54

Zebra finches are sensitive to prosodic features of human speech.  

Science.gov (United States)

Variation in pitch, amplitude and rhythm adds crucial paralinguistic information to human speech. Such prosodic cues can reveal information about the meaning or emphasis of a sentence or the emotional state of the speaker. To examine the hypothesis that sensitivity to prosodic cues is language independent and not human specific, we tested prosody perception in a controlled experiment with zebra finches. Using a go/no-go procedure, subjects were trained to discriminate between speech syllables arranged in XYXY patterns with prosodic stress on the first syllable and XXYY patterns with prosodic stress on the final syllable. To systematically determine the salience of the various prosodic cues (pitch, duration and amplitude) to the zebra finches, they were subjected to five tests with different combinations of these cues. The zebra finches generalized the prosodic pattern to sequences that consisted of new syllables and used prosodic features over structural ones to discriminate between stimuli. This strong sensitivity to the prosodic pattern was maintained when only a single prosodic cue was available. The change in pitch was treated as more salient than changes in the other prosodic features. These results show that zebra finches are sensitive to the same prosodic cues known to affect human speech perception. PMID:24870039

Spierings, Michelle J; ten Cate, Carel

2014-07-22

55

Origin of Zebra Pattern in Type IV Solar Radio Emission  

Science.gov (United States)

Strong and weak aspects of different theories of fine structures in solar radio emission dynamic spectra observed as several or numerous quasi-equidistant bands of enhanced and reduced radiation (zebra pattern) are discussed. Most of the works which propose zebra pattern interpretation are based on the plasma mechanism of radio emission generation, which consists of excitation of plasma (electrostatic) waves and their subsequent transformation into electromagnetic emission. Plasma waves arise due to kinetic or hydrodynamic instability at the upper hybrid frequencies at the levels of double plasma resonance in a distributed source. Some works are devoted to considering whistlers as the main reason for stripes in emission and absorption occurring in the dynamic spectra. An alternative theory of zebra pattern origin suggests that of a compact source with trapped plasma waves is present in the corona. Another interpretation is based on special effects that may occur when radio waves propagate through some periodic structure in the corona. All suggested mechanisms are analysed with relation to their capability to give the best fit for the observed fine structure features in the framework of the source model with reasonable physical parameters. It is shown that the theory based on the effect of double plasma resonance in a nonhomogeneous coronal loop is the best-developed theory for the origin of zebra pattern at the meter-decimetre wavelengths at the present time.

Zlotnik, E. Ya.

56

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

57

On the Origin of the Zebra Pattern with Pulsating Superfine Structures on 21 April 2002  

Science.gov (United States)

Through the data around 3 GHz from the Radio Spectrometer in Huairou, Beijing, zebra-pattern structures from the 21 April 2002 event have been studied. Zebra stripes consist of periodically pulsating superfine structures in this event. An analysis of temporal profiles of intensities at multiple frequency channels shows that the Gaussian temporal profiles of pulse groups on zebra stripes are caused by drifting zebra stripes with Gaussian spectral profiles. The observed quasiperiodic pulsations with about 30 ms period have a peculiar feature of oscillation near a steady state, probably resulting from relaxation oscillations, which modulate the electron cyclotron maser emission that forms the zebra stripes during the process of wave particle interactions. All the main properties of the zebra stripes with pulsating superfine structures indicate that the double plasma resonance model might be the most suitable one, with the relaxation oscillations, to form the superfine structures. The model of LaBelle et al. ( Astrophys. J. 593, 1195, 2003) could not account for the observed properties of zebra-pattern structures in this event nor for most zebra-pattern structures occupying a wide frequency range, mainly because the allowable frequency range of the zebra-pattern structures in their model is too narrow to reproduce the observed zebras.

Chen, Bin; Yan, Yihua

2007-12-01

58

Frequency variations of solar radio zebras and their power-law spectra  

Science.gov (United States)

Context. During solar flares several types of radio bursts are observed. The fine striped structures of the type IV solar radio bursts are called zebras. Analyzing them provides important information about the plasma parameters of their radio sources. We present a new analysis of zebras. Aims: Power spectra of the frequency variations of zebras are computed to estimate the spectra of the plasma density variations in radio zebra sources. Methods: Frequency variations of zebra lines and the high-frequency boundary of the whole radio burst were determined with and without the frequency fitting. The computed time dependencies of these variations were analyzed with the Fourier method. Results: First, we computed the variation spectrum of the high-frequency boundary of the whole radio burst, which is composed of several zebra patterns. This power spectrum has a power-law form with a power-law index -1.65. Then, we selected three well-defined zebra-lines in three different zebra patterns and computed the spectra of their frequency variations. The power-law indices in these cases are found to be in the interval between -1.61 and -1.75. Finally, assuming that the zebra-line frequency is generated on the upper-hybrid frequency and that the plasma frequency ?pe is much higher than the electron-cyclotron frequency ?ce, the Fourier power spectra are interpreted to be those of the electron plasma density in zebra radio sources.

Karlický, M.

2014-01-01

59

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

OpenAIRE

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 discuss what these studies can teach us about the evolutionary and behavioural ecology of Zebra Finches and song birds in general, and make suggestions for future research. Throughout this article we ple...

Tschirren, B.; Postma, E.

2010-01-01

60

Relative salience of envelope and fine structure cues in zebra finch song  

OpenAIRE

Zebra finches produce a learned song that is rich in harmonic structure and highly stereotyped. More is generally known about how birds learn and produce this song than how they perceive it. Here, zebra finches were trained with operant techniques to discriminate changes in natural and synthetic song motifs. Results show that zebra finches are quite insensitive to changes to the overall envelope of the motif since they were unable to discriminate more than a doubling in inter-syllable interva...

Vernaleo, Beth A.; Dooling, Robert J.

2011-01-01

61

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

OpenAIRE

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...

Tan, Baolin

2009-01-01

62

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

OpenAIRE

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 factors and fish predation on the density of zebra mussels at several sites and between years in a natural lake. Water depth and roach (Rutilus rutilus) density were the most important variables affecti...

Naddafi, Rahmat; Pettersson, Kurt; Eklo?v, Peter

2010-01-01

63

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

OpenAIRE

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...

Faisal Mohamed; Xu Wei

2010-01-01

64

STRUCTURAL AND FUNCTIONNAL STUDIES OF THE COMPLEX ZEBRA/METHYLATED DNA  

OpenAIRE

Epstein-Barr virus is a ?-herpesvirus that infects over 95% of the world population. The viral transcription factor ZEBRA is responsible for switching infection from the latent to the lytic phase. ZEBRA, a member of the (bZIP) protein family, activates the promoters of lytic EBV genes by recognizing specific DNA sites called ZEBRA-responsive elements (ZREs). ZEBRA binds preferentially to certain ZREs when these are methylated on CpG motifs, including a key target site (ZRE2) within the promo...

Pagniez, Priscilla

2008-01-01

65

Remote Cerebellar Hemorrhage after Frontal Lobectomy: Zebra Sign  

OpenAIRE

Remote cerebellar hemorrhages (RCHs) are rare complications of intracranial or spinal interventions. We describe a patient with an RCH that occurred after a frontal lobectomy for an intracranial tumor. A 41-year-old female patient with a headache and partial seizures underwent a right frontal lobectomy upon detection of a right frontal mass. An RCH (zebra sign) was detected on a control cranial computed tomography (CT), which was performed upon detection of frontal lobe syndrome and mild atax...

Can Yaldiz; Volkan Murat Unal; Omer Akar; Onur Yaman; Nail Ozdemir

2014-01-01

66

The recombination landscape of the zebra finch Taeniopygia guttata genome  

OpenAIRE

Understanding the causes and consequences of variation in the rate of recombination is essential since this parameter is considered to affect levels of genetic variability, the efficacy of selection, and the design of association and linkage mapping studies. However, there is limited knowledge about the factors governing recombination rate variation. We genotyped 1920 single nucleotide polymorphisms in a multigeneration pedigree of more than 1000 zebra finches (Taeniopygia guttata) to develop...

Backstro?m, Niclas; Forstmeier, Wolfgang; Schielzeth, Holger; Mellenius, Harriet; Nam, Kiwoong; Bolund, Elisabeth; Webster, Matthew T.; O?st, Torbjo?rn; Schneider, Melanie; Kempenaers, Bart; Ellegren, Hans

2010-01-01

67

Mammalian-like features of sleep structure in zebra finches  

OpenAIRE

A suite of complex electroencephalographic patterns of sleep occurs in mammals. In sleeping zebra finches, we observed slow wave sleep (SWS), rapid eye movement (REM) sleep, an intermediate sleep (IS) stage commonly occurring in, but not limited to, transitions between other stages, and high amplitude transients reminiscent of K-complexes. SWS density decreased whereas REM density increased throughout the night, with late-night characterized by substantially more REM than SWS, and relatively ...

Low, Philip Steven; Shank, Sylvan S.; Sejnowski, Terrence J.; Margoliash, Daniel

2008-01-01

68

Do Zebra Finch Parents Fail to Recognise Their Own Offspring?  

OpenAIRE

Individual recognition systems require the sender to be individually distinctive and the receiver to be able to perceive differences between individuals and react accordingly. Many studies have demonstrated that acoustic signals of almost any species contain individualized information. However, fewer studies have tested experimentally if those signals are used for individual recognition by potential receivers. While laboratory studies using zebra finches have shown that fledglings recognize t...

Reers, Hendrik; Jacot, Alain; Forstmeier, Wolfgang

2011-01-01

69

Digital gene expression analysis of the zebra finch genome  

OpenAIRE

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 m...

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

2010-01-01

70

Development of temporal structure in zebra finch song  

OpenAIRE

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 variabilit...

Glaze, Christopher M.; Troyer, Todd W.

2012-01-01

71

Opioid modulation of song in male zebra finches (Taenopygia guttata).  

Science.gov (United States)

Endogenous opioids are known to modulate motivated behaviors. Male zebra finches produce a highly motivated behavior (directed song) to court females and also sing in isolation (undirected song). We found that adult male zebra finches sang significantly fewer directed and undirected songs after administration of low doses (2.5 mg/kg body weight) of the general opioid antagonist naloxone, even though the order of syllables in songs was not altered. Surprisingly, high doses of naloxone (10 mg/kg body weight) dramatically decreased the production of undirected songs but had no significant effects on directed songs. There were no changes in the number of calls during directed or undirected song, movement, stereotyped behaviors including pecking and preening, feeding or drinking behaviors after naloxone administration. We also found that treating zebra finches with naloxone led to a decrease in tonality (goodness of pitch), frequency and amplitude modulation and an increase in the length of intersyllable intervals. Our results suggest that the opioid system can differentially modulate directed and undirected song as well as the acoustic characteristics of birdsong, perhaps by acting on different components of the song control system. PMID:20015456

Khurshid, Nazia; Jayaprakash, Navin; Hameed, L Shahul; Mohanasundaram, Sivaraj; Iyengar, Soumya

2010-04-01

72

A Subset of Replication Proteins Enhances Origin Recognition and Lytic Replication by the Epstein-Barr Virus ZEBRA Protein  

OpenAIRE

ZEBRA is a site-specific DNA binding protein that functions as a transcriptional activator and as an origin binding protein. Both activities require that ZEBRA recognizes DNA motifs that are scattered along the viral genome. The mechanism by which ZEBRA discriminates between the origin of lytic replication and promoters of EBV early genes is not well understood. We explored the hypothesis that activation of replication requires stronger association between ZEBRA and DNA than does transcriptio...

El-guindy, Ayman; Heston, Lee; Miller, George

2010-01-01

73

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)

74

LC-MS Analysis of Phenolic Compounds in Tubers Showing Zebra Chip Symptoms  

Science.gov (United States)

A new potato disorder called zebra chip (ZC) has been identified in the United States and has been especially problematic in Texas where substantial economic losses have been incurred. Upon frying, ZC tubers develop a dark “zebra chip” pattern of discoloration. LC-MS analysis of symptomatic tubers...

75

The Efficiency of Electron Acceleration in Solar Type-IV Radio Pulsations with a Zebra Pattern  

Science.gov (United States)

Based on a comprehensive analysis of the October 25, 1994 event, we consider the balance of energetic particles in a type-IV solar radio emission source with a zebra-type fine structure (in a coronal magnetic loop). The zebra pattern is formed through the injection of fast electrons into a trap and the formation of a ring-type nonequilibrium electron distribution function. We estimated the characteristic zebra-pattern lifetime, which is determined by the escape of fast particles from the trap into the loss cone. In addition, we determined the number of fast particles that must be injected into the trap to provide the observed radio brightness temperature in zebra-pattern stripes by analyzing the plasma emission mechanism responsible for the zebra-pattern generation. As a result, we estimated the efficiency of the electron acceleration mechanism in coronal magnetic loops at the post-flare evolutionary phase of an active region.

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

2005-04-01

76

Preference of redear sunfish on zebra mussels and rams-horn snails  

Science.gov (United States)

We tested prey preferences of adult (200- to 222-mm long) redear sunfish (Lepomis microlophus) on two size classes of zebra mussels (Dreissena polymorpha) and two-ridge rams-horns (Helisoma anceps) in experimental aquaria. We also tested physical limitations on consuming these mollusks and determined prey bioenergetic profitability. Redear sunfish strongly preferred rams-horns over zebra mussles, but they displayed no size preference for either prey. Ingestion was not physically limited since both prey species up to 15-mm long fit within the pharyngeal gapes of redear sunfish. Rams-horns were more bioenergetically profitable than zebra mussles and ingestion of rams-horn shell fragments was about three times less than zebra mussels. Rams-horns were somewhat more resistant to shell-crushing, but all size ranges of both prey species tested were crushable by redear sunfish. These studies suggested that the redear sunfish should not be considered a panacea for biological control of zebra mussels.

French, John R. P., III; Morgan, Michael N.

1995-01-01

77

Illustrated identification keys to strongylid parasites (Strongylidae: Nematoda) of horses, zebras and asses (Equidae).  

Science.gov (United States)

The Equidae (the horse, Equus caballus, the ass, Equus asinus, zebras and their hybrids) are hosts to a great variety of nematode parasites, some of which can cause significant morbidity or mortality if individual hosts are untreated. Worldwide the nematode parasites of horses belong to 7 suborders, 12 families, 29 genera and 83 species. The great majority (19 of 29 genera and 64 of 83 species) are members of the family Strongylidae, which includes the most common and pathogenic nematode parasites of horses. Only the Strongylidae are included in this treatise. The Strongylidae (common name strongylids) of horses--nematodes with a well-developed buccal capsule, a mouth collar with two leaf-crowns, and a strongyloid (common name of superfamily Strongyloidea) copulatory bursa--can be separated into two subfamilies: Strongylinae (common name strongylins), usually large or medium-sized with a globular or funnel-shaped buccal capsule; and Cyathostominae (common name cyathostomins), usually small to medium-sized with a cylindrical buccal capsule. The increased attention to strongylid nematode parasites of horses has resulted in the need for updated diagnostic keys to these parasites using readily recognizable characters and the most recent literature on their systematics. Because the cyathostomins have been historically difficult to identify, and because they have emerged as the most significant nematode pathogens of horses, we provide a brief nomenclatural and taxonomic history and an introduction to the morphology of this group. This treatise is intended to serve as a basic working tool--providing easy identifications to genus and species of adult strongylid nematodes of equids. All strongylid nematodes normally parasitic in horses, the ass (and their hybrids), and zebras are included. The keys are illustrated with line drawings and halftone photomicrographs of each species. A short discussion of the systematics of the genus and species is provided for each genus following the species descriptions. Species diagnoses and a synonymy of each species is provided. Geographic distribution, prevalence, and location in host are also given for each species. PMID:18603375

Lichtenfels, J Ralph; Kharchenko, Vitaliy A; Dvojnos, Grigory M

2008-09-15

78

Social inhibition of song imitation among sibling male zebra finches  

OpenAIRE

A male zebra finch, Taeniopygia guttata, kept with its father until adulthood develops an imitation of its father’s song motif. We report here that the completeness of this imitation was sensitive to the social or auditory context in which the bird grew up: the greater the number of male siblings in a clutch, the shorter the mean duration of the song motif and the fewer the mean number of song notes imitated from the father; the latter shortfall was not compensated by other, improvised note...

Tchernichovski, Ofer; Nottebohm, Fernando

1998-01-01

79

Saprolegnia brachydanis, a new oomycete isolated from zebra fish.  

Science.gov (United States)

Saprolegnia brachydanis is described from zebra fish (Brachydanio rerio) in Wuhan, Hubei Province, China. The species is illustrated and compared with other species of the genus. The distinctive characteristics of S. brachydanis are the production of glomerulate oogonia wrapped around by predominantly monoclinous antheridia which can be up to eight in one oogonium. The oogonial stalks are short, straight, or curved and the antheridia, twisted, can enwind one or more oogonia. The oospores cannot mature or easily abort. Morphological features of the oomycete and the ITS sequence of its rDNA as well as the comparison with related species are discussed in this article. PMID:18853279

Ke, Xiaoli; Wang, Jianguo; Gu, Zemao; Li, Ming; Gong, Xiaoning

2009-02-01

80

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

81

The acoustic effect of vocal tract adjustments in zebra finches.  

Science.gov (United States)

Vocal production in songbirds requires the control of the respiratory system, the syrinx as sound source and the vocal tract as acoustic filter. Vocal tract movements consist of beak, tongue and hyoid movements, which change the volume of the oropharyngeal-esophageal cavity (OEC), glottal movements and tracheal length changes. The respective contributions of each movement to filter properties are not completely understood, but the effects of this filtering are thought to be very important for acoustic communication in birds. One of the most striking movements of the upper vocal tract during vocal behavior in songbirds involves the OEC. This study measured the acoustic effect of OEC adjustments in zebra finches by comparing resonance acoustics between an utterance with OEC expansion (calls) and a similar utterance without OEC expansion (respiratory sounds induced by a bilateral syringeal denervation). X-ray cineradiography confirmed the presence of an OEC motor pattern during song and call production, and a custom-built Hall-effect collar system confirmed that OEC expansion movements were not present during respiratory sounds. The spectral emphasis during zebra finch call production ranging between 2.5 and 5 kHz was not present during respiratory sounds, indicating strongly that it can be attributed to the OEC expansion. PMID:23085986

Riede, Tobias; Schilling, Nadja; Goller, Franz

2013-01-01

82

'Fitness Testing' for Children: Let's Mount the Zebra!  

Science.gov (United States)

Few paediatric health topics have sparked as much academic and public debate as school-based fitness testing. Since Rowland exclaimed nearly two decades ago that the "horse", referring to school-based fitness testing is dead, opinion has been divided - to test or not to test. Whilst many agreed with Rowland`s criticisms, others suggest that it is not school-based fitness testing per se that is problematic but that we have been riding the wrong animal, and should instead be riding a zebra - signifying a multi-dimensional approach to its implementation. We acknowledge concerns over school-based fitness testing, but argue that the associations between fitness and health, as well as the secular declines in fitness, necessitate such monitoring. More importantly, we highlight several potential opportunities for fitness testing, to not only to map an important aspect of health, but also to improve physical self-concept and challenge the misconception that leanness equates to good health and fitness and its corollary; that fatness is invariably associated with poor fitness and health. We believe that a carefully chosen fitness test battery delivered in an educational context, can transform the horse into the zebra, and it is time for the skilful rider to mount and ride it. PMID:24905807

Cohen, Daniel; Voss, Christine; Sandercock G, R H

2014-06-01

83

Copper Wire Arrays at the 1 MA Zebra Facility  

Science.gov (United States)

Experiments to study the implosion dynamics and radiation characteristics of copper z-pinches have been fielded at the 1 MA Zebra facility. At Zebra, load diameters ranged from 8mm to 16mm, with 6 to 14 wires, and load masses of 80 to 200 ?g. All arrays utilized 10 micron diameter wire. The impact of initial load mass and initial load diameter on the precursor and the stagnated plasma has been evaluated through spectroscopy, shadowgraphy, and fluence measurements. Plasma parameters have been extracted from modeling of the time-integrated L-shell spectra to study temperature and density variations as a function of spatial position and initial load configuration. Comparisons will be made with harder x-ray spectra and pinhole images to identify regions of highest temperature and density. Shadowgraphy has been fielded to study the formation of the precursor and the main implosion; significant structure is observed. Substantial radiation is observed from the precursor, with variations in the precursor associated with initial load configuration. *Sandia is a multi-program laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.

Coverdale, C. A.; Jones, B.; Ampleford, D. J.; Deeney, C.; Lepell, P. D.; Safronova, A. S.; Kantsyrev, V. L.; Ouart, N.; Ivanov, V. V.

2006-10-01

84

Longitudinal patterns in abundance of the zebra mussel (Dreissena polymorpha) in the upper Mississippi River  

Science.gov (United States)

We assessed the abundance of zebra mussels in the upper Mississippi River during 1995, four years after they were first found in the river. Samplers were deployed from May 30 to October 19, 1995, at 19 lock and dam facilities in the upper Mississippi River from Minneapolis, Minnesota, to Muscatine, Iowa. Zebra mussels were found at every lock and dam except the two sites farthest upstream (Minneapolis). Generally, densities of zebra mussels were greatest at sites 161 km and farther downstream of the Minneapolis area. The greatest mean mussel density was 11,432/m(2) at Fulton, Illinois.

Cope, W.G.; Bartsch, M.R.; Hayden, R.R.

1997-01-01

85

Caractérisation de l'ubinucléine, partenaire cellulaire du transactivateur ZEBRA du virus d'Epstein-Barr  

OpenAIRE

Le facteur de transcription ZEBRA (EB1) du virus d'Epstein-Barr joue un rôle essentiel dans l'initiation de l'infection lytique et la production virale. L'ubinucléine a été identifiée comme un partenaire cellulaire de ZEBRA, capable de l'empêcher de se fixer à ses séquences d'ADN cibles. Le rôle de l'ubinucléine dans la cellule demeure inconnu, ainsi que les conséquences de son interaction avec ZEBRA dans les cellules infectées par l'EBV. Notre travail a permis, d'abord, de mieux ...

Lupo, Julien

2010-01-01

86

Stabilization of sexual preferences by sexual experience in male zebra finches, taeniopygia guttata castanotis  

OpenAIRE

Male zebra finches, Taeniopygia guttala castanotis, were normally-raised by zebra finches or were cross-fostered to Bengalese finch, Lonchura striata, foster-parents until 40 days of age. Following isolation until day 100, half the birds in each group were housed with a zebra finch female for seven days, isolated for three days and then housed with a Bengalese finch female for seven days. The other birds were exposed to females in the reverse order. Subsequent double-choice tests showed that ...

Bischof, Hans-joachim; Clayton, Nicky

1991-01-01

87

IRPHE-ZEBRA, AEEW Fast Reactor Experiments, Primary Documentation  

International Nuclear Information System (INIS)

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 slowers 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

88

Pattern of faecal 20-oxopregnane and oestrogen concentrations during pregnancy in wild plains zebra mares.  

Science.gov (United States)

Regulative endocrine mechanisms influence the reproductive behaviour and success of mammals, but they have been studied predominantly in domestic and captive animals. The study aims at describing the pattern of faecal 20-oxopregnane and oestrogen concentrations during pregnancy in wild plains zebra Equus quagga chapmani. Data were collected during wet and dry seasons 2007-2009. Enzyme Immunoassays were used to determine 20-oxopregnane and oestrogen concentrations in faecal samples (n=74) collected from individual mares (n=32) whose dates of foaling were known through long-term monitoring. Hormonal profiles were described with a General Additive Model (GAM: Hormone ? Days to Foaling). Faecal 20-oxopregnanes have a complex cycle during pregnancy (GAM, n=70, R(2)=0.616, p200 ng/g DW) of faecal 20-oxopregnanes associated with high (>160 ng/g DW) faecal oestrogen levels indicate mid-pregnancy in c.90% of cases (16/17). High faecal 20-oxopregnanes (>200 ng/g DW) and low faecal oestrogen levels (<160 ng/g DW) indicate late pregnancy, again in c.90% of cases. Two faecal samples would allow the stage of pregnancy to be determined with confidence. PMID:21463629

Ncube, Hlengisizwe; Duncan, Patrick; Grange, Sophie; Cameron, Elissa Z; Barnier, Florian; Ganswindt, Andre

2011-07-01

89

Dissection and downstream analysis of zebra finch embryos at early stages of development.  

Science.gov (United States)

The zebra finch (Taeniopygiaguttata) has become an increasingly important model organism in many areas of research including toxicology, behavior, and memory and learning. As the only songbird with a sequenced genome, the zebra finch has great potential for use in developmental studies; however, the early stages of zebra finch development have not been well studied. Lack of research in zebra finch development can be attributed to the difficulty of dissecting the small egg and embryo. The following dissection method minimizes embryonic tissue damage, which allows for investigation of morphology and gene expression at all stages of embryonic development. This permits both bright field and fluorescence quality imaging of embryos, use in molecular procedures such as in situ hybridization (ISH), cell proliferation assays, and RNA extraction for quantitative assays such as quantitative real-time PCR (qtRT-PCR). This technique allows investigators to study early stages of development that were previously difficult to access. PMID:24999108

Murray, Jessica R; Stanciauskas, Monika E; Aralere, Tejas S; Saha, Margaret S

2014-01-01

90

Spatial Unmasking of Birdsong in Zebra Finches (Taeniopygia guttata) and Budgerigars (Melopsittacus undulatus)  

OpenAIRE

Budgerigars and zebra finches were tested, using operant conditioning techniques, on their ability to identify a zebra finch song in the presence of a background masker emitted from either the same or a different location as the signal. Identification thresholds were obtained for three masker types differing in their spectrotemporal characteristics (noise, modulated noise, and a song chorus). Both bird species exhibited similar amounts of spatial unmasking across the three masker types. The a...

Dent, Micheal L.; Mcclaine, Elizabeth M.; Best, Virginia; Ozmeral, Erol; Narayan, Rajiv; Gallun, Frederick J.; Sen, Kamal; Shinn-cunningham, Barbara G.

2009-01-01

91

LEARNING-RELATED CHANGES IN THE FUNCTIONAL CONNECTIVITY WITHIN THE ZEBRA FINCH SONG-CONTROL CIRCUIT  

OpenAIRE

Many species-specific sensorimotor behaviors, such as speech in humans, emerge from the interplay between genetically defined developmental programs and sensory experience. How these processes interact during learning to shape motor circuits is not well understood. The zebra finch (Taeniopygia guttata), an oscine bird that learns to imitate the song of its tutor (usually the father), provides a uniquely tractable model for exploring this question. Song learning in zebra finches takes place du...

Garst Orozco, Jonathan

2014-01-01

92

The gaping reaction and the development of fear in young zebra finches (Taeniopygia guttata castanotis)  

OpenAIRE

Responses of young zebra finches towards different stimuli were tested between hatching and 20 days of age. The stimuli applied were: tactile stimulation with a stick, acoustic stimulation from a loudspeaker playing begging calls of other nestlings, and stuffed dummies of zebra finches and Bengalese finches as visual stimuli. Tactile and acoustic stimuli resulted in gaping responses from the first day of life. Visual stimuli elicited gaping from about day 10 or 11, 4 days after the opening of...

Bischof, Hans-joachim; Lassek, Reinhard

1985-01-01

93

Sex differences in cell proliferation and glucocorticoid responsiveness in the zebra finch brain  

OpenAIRE

Neural proliferation is a conserved property of the adult vertebrate brain. In mammals, stress reduces hippocampal neuronal proliferation and the effect is stronger in males than in females. We tested the effects of glucocorticoids on ventricular zone cell proliferation in adult zebra finches where neurons are produced that migrate to and incorporate within the neural circuits controlling song learning and performance. Adult male zebra finches sing and have an enlarged song circuitry; females...

Katz, Amnon; Mirzatoni, Anahid; Zhen, Yin; Schlinger, Barney A.

2008-01-01

94

Castration modulates singing patterns and electrophysiological properties of RA projection neurons in adult male zebra finches  

OpenAIRE

Castration can change levels of plasma testosterone. Androgens such as testosterone play an important role in stabilizing birdsong. The robust nucleus of the arcopallium (RA) is an important premotor nucleus critical for singing. In this study, we investigated the effect of castration on singing patterns and electrophysiological properties of projection neurons (PNs) in the RA of adult male zebra finches. Adult male zebra finches were castrated and the changes in bird song assessed. We also r...

Songhua Wang; Congshu Liao; Fengling Li; Shaoyi Liu; Wei Meng; Dongfeng Li

2014-01-01

95

Late-Postnatal Cannabinoid Exposure Persistently Increases FoxP2 Expression within Zebra Finch Striatum  

OpenAIRE

Prior work has shown that cannabinoid exposure of zebra finches during sensorimotor stages of vocal development alters song patterns produced in adulthood. We are currently working to identify physiological substrates for this altered song learning. FoxP2 is a transcription factor associated with altered vocal development in both zebra finches and humans. This protein shows a distinct pattern of expression within Area X of striatum that coincides with peak expression of CB1 cannabinoid recept...

Soderstrom, Ken; Luo, Bin

2010-01-01

96

Condition dependence and fitness consequences of sexual traits in zebra finches  

OpenAIRE

The focus of this thesis is on sexual selection within a behavioural and evolutionary framework. Sexual selection is concerned with the factors that determine reproductive success. I have used a laboratory population of zebra finches to address fundamental questions that remain unanswered despite decades of research on this model organism in studies of sexual selection in monogamous species. The aim of this thesis was to perform a rigorous investigation of how male zebra finches achieve repro...

Bolund, Elisabeth

2009-01-01

97

Effects of Long-Term Flutamide Treatment During Development In Zebra Finches  

OpenAIRE

The molecular mechanisms responsible for the sexual differentiation of the zebra finch song system remain mysterious. Androgen receptors are expressed in a sexually dimorphic fashion in the zebra finches song system: males have more cells expressing androgen receptors, and this sex difference appears very early in development (day 9 posthatch). Estrogen administration to hatchling females up-regulates androgen receptor expression in their song system and profoundly masculinizes their song sys...

Grisham, William; Park, Sun Hee; Hsia, Jennifer K.; Kim, Caroline; Leung, Michael C.; Kim, Linda; Arnold, Arthur P.

2007-01-01

98

Genomic and neural analysis of the estradiol-synthetic pathway in the zebra finch  

OpenAIRE

Abstract Background Steroids are small molecule hormones derived from cholesterol. Steroids affect many tissues, including the brain. In the zebra finch, estrogenic steroids are particularly interesting because they masculinize the neural circuit that controls singing and their synthesis in the brain is modulated by experience. Here, we analyzed the zebra finch genome assembly to assess the content, conservation, and organization of genes that code for components of the estro...

London Sarah E; Clayton David F

2010-01-01

99

Formation of zebra pattern in low-frequency Jovian radio emission  

OpenAIRE

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 ...

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

2012-01-01

100

Removal of algae by the zebra mussel (Dreissena polymorpha) population in western Lake Erie: a bioenergetics approach  

Science.gov (United States)

A bioenergetics model for growth of a zebra mussel (Dreissena polymorpha) individual was verified with observations on zebra mussel growth in western Lake Erie. The bioenergetics model was then applied to the zebra mussel population in the western basin of Lake Erie to estimate the removal of phytoplankton by mussels. According to the modeling results, the zebra mussel population consumed 5.0 million tonnes of phytoplankton, while 1.4 million tonnes of phytoplankton was deposited in pseudofeces from the mussels. Thus, a total of 6.4 A? 2.4 million tonnes of phytoplankton was removed from the water column by zebra mussel in western Lake Erie during 1990. Primary production was estimated to be 24.8 million tonnes; therefore, zebra mussel removed the equivalent of 26 A? 10% of the primary production for western Lake Erie.

Madenjian, Charles P.

1995-01-01

101

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

102

Changing Epstein-Barr viral ZEBRA protein into a more powerful activator enhances its capacity to disrupt latency.  

OpenAIRE

The Epstein-Barr viral transcriptional activator ZEBRA induces expression of viral early lytic genes when introduced into cells bearing latent Epstein-Barr virus. We show here that a ZEBRA-herpes simplex viral protein 16 (VP16) fusion protein induces early viral lytic gene expression in Epstein-Barr virus-containing cells more efficiently than does wild-type ZEBRA. The fusion protein is also a more powerful transcriptional activator in these cells, as assayed with reporter constructs. Our exp...

Baumann, R.; Grogan, E.; Ptashne, M.; Miller, G.

1993-01-01

103

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

104

IMPACT OF OXYGEN CONCENTRATION ON ZEBRA MUSSEL MORTALITY  

International Nuclear Information System (INIS)

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

105

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

106

Unusual Zebra Patterns in the Decimeter Wave Band  

Science.gov (United States)

An analysis of new observations showing fine structures consisting of narrowband fiber bursts as substructures of large-scale zebra-pattern stripes is carried out. We study four events using spectral observations taken with a newly built spectrometer located at the Huairou station, China, in the frequency range of 1.1 - 2.0 GHz with extremely high frequency and time resolutions (5 MHz and 1.25 ms). All the radio events were analyzed by using the available satellite data (SOHO LASCO, EIT, and MDI, TRACE, and RHESSI). Small-scale fibers always drift to lower frequencies. They may belong to a family of ropelike fibers and can also be regarded as fine structures of type III bursts and broadband pulsations. The radio emission was moderately or strongly polarized in the ordinary wave mode. In three main events fiber structure appeared as a forerunner of the entire event. All four events were small decimeter bursts. We assume that for small-scale fiber bursts the usual mechanism of coalescence of whistler waves with plasma waves can be applied, and the large-scale zebra pattern can be explained in the conventional double plasma resonance (DPR) model. The appearance of an uncommon fine structure is connected with the following special features of the plasma wave excitation in the radio source: Both whistler and plasma wave instabilities are too weak at the very beginning of the events ( i.e., the continuum was absent), and the fine structure is almost invisible. Then, whistlers generated directly at DPR levels “highlight” the radio emission only from these levels owing to their interaction with plasma waves.

Chernov, G. P.; Yan, Yihua; Fu, Qijun; Tan, Chengming; Wang, Shujuan

2008-07-01

107

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

108

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

OpenAIRE

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 kinase II (CKII). The principal site of phosphorylation is serine-173 (S173), five amino acids upstream of the basic DNA recognition domain. CKII phosphorylation abrogated ZEBRA's capacity to bind its...

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

1993-01-01

109

A physical explanation of solar microwave Zebra pattern with the current-carrying plasma loop model  

Science.gov (United States)

The microwave Zebra pattern structure is an intriguing fine structure on the dynamic spectra of solar type IV radio bursts. Up to now, there is no perfect physical model for the origin of the solar microwave Zebra pattern. Recently, Ledenev et al. (Sol. Phys. 233:129, 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 a current-carrying plasma loop and the theory of tearing-mode instability, we propose 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 loops.

Tan, Baolin

2010-02-01

110

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

Science.gov (United States)

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.

Laptukhov, A. I.; Chernov, G. P.

2009-02-01

111

Artificial grammar learning in zebra finches and human adults: XYX versus XXY.  

Science.gov (United States)

Abstracting syntactic rules is critical to human language learning. It is debated whether this ability, already present in young infants, is human- and language specific or can also be found in non-human animals, indicating it may arise from more general cognitive mechanisms. Current studies are often ambiguous and few have directly compared rule learning by humans and non-human animals. In a series of discrimination experiments, we presented zebra finches and human adults with comparable training and tests with the same artificial stimuli consisting of XYX and XXY structures, in which X and Y were zebra finch song elements. Zebra finches readily discriminated the training stimuli. Some birds also discriminated novel stimuli when these were composed of familiar element types, but none of the birds generalized the discrimination to novel element types. We conclude that zebra finches show evidence of simple rule abstraction related to positional learning, suggesting stimulus-bound generalization, but found no evidence for a more abstract rule generalization. This differed from the human adults, who categorized novel stimuli consisting of novel element types into different groups according to their structure. The limited abilities for rule abstraction in zebra finches may indicate what the precursors of more complex abstraction as found in humans may have been like. PMID:25015135

Chen, Jiani; van Rossum, Danielle; Ten Cate, Carel

2014-07-12

112

Rotationally driven 'zebra stripes' in Earth's inner radiation belt.  

Science.gov (United States)

Structured features on top of nominally smooth distributions of radiation-belt particles at Earth have been previously associated with particle acceleration and transport mechanisms powered exclusively by enhanced solar-wind activity. Although planetary rotation is considered to be important for particle acceleration at Jupiter and Saturn, the electric field produced in the inner magnetosphere by Earth's rotation can change the velocity of trapped particles by only about 1-2 kilometres per second, so rotation has been thought inconsequential for radiation-belt electrons with velocities of about 100,000 kilometres per second. Here we report that the distributions of energetic electrons across the entire spatial extent of Earth's inner radiation belt are organized in regular, highly structured and unexpected 'zebra stripes', even when the solar-wind activity is low. Modelling reveals that the patterns are produced by Earth's rotation. Radiation-belt electrons are trapped in Earth's dipole-like magnetic field, where they undergo slow longitudinal drift motion around the planet because of the gradient and curvature of the magnetic field. Earth's rotation induces global diurnal variations of magnetic and electric fields that resonantly interact with electrons whose drift period is close to 24 hours, modifying electron fluxes over a broad energy range into regular patterns composed of multiple stripes extending over the entire span of the inner radiation belt. PMID:24646996

Ukhorskiy, A Y; Sitnov, M I; Mitchell, D G; Takahashi, K; Lanzerotti, L J; Mauk, B H

2014-03-20

113

Proteomic analyses of zebra finch optic tectum and comparative histochemistry.  

Science.gov (United States)

Proteomic analyses of zebra finch (Taeniopygia guttata) optic tectum resulted in identification of 176 proteins. In the Swissprot database, only 52 proteins were identified as bird homologs and only 71 proteins were identified in songbird transcriptome databases, reflecting a lack of completeness in the T. guttata genomic sequence. Analysis in Kyoto encyclopedia of genes and genome (KEGG) pathway database found that identified proteins most frequently belong to glucose, pyruvate, glyoxylate, dicarboxylate, alanine, and aspartate metabolism pathways. A number of identified proteins have been previously reported to exist in the avian optic tectum. The immunohistochemical localization of selected proteins showed their distribution in similar laminae of the owl (Tyto alba) and chicken (Gallus gallus) tectum. Immunohistochemical analysis of identified proteins can provide clues about cell types and circuit layout of the avian optic tectum in general. As the optic tectum of nonmammals is homologous to the superior colliculus of mammals, the analysis of the tectal and collicular proteome may provide clues about conserved cell and circuit layout, circuit function, and evolution. PMID:17497909

Sloley, Stephanie; Smith, Shannon; Gandhi, Sonia; Busby, Jennifer A Caldwell; London, Sarah; Luksch, Harald; Clayton, David F; Bhattacharya, Sanjoy K

2007-06-01

114

Prevention and control of zebra mussels: proactive and reactive strategies  

International Nuclear Information System (INIS)

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)

115

Drinking Songs: Alcohol Effects on Learned Song of Zebra Finches  

Science.gov (United States)

Speech impairment is one of the most intriguing and least understood effects of alcohol on cognitive function, largely due to the lack of data on alcohol effects on vocalizations in the context of an appropriate experimental model organism. Zebra finches, a representative songbird and a premier model for understanding the neurobiology of vocal production and learning, learn song in a manner analogous to how humans learn speech. Here we show that when allowed access, finches readily drink alcohol, increase their blood ethanol concentrations (BEC) significantly, and sing a song with altered acoustic structure. The most pronounced effects were decreased amplitude and increased entropy, the latter likely reflecting a disruption in the birds’ ability to maintain the spectral structure of song under alcohol. Furthermore, specific syllables, which have distinct acoustic structures, were differentially influenced by alcohol, likely reflecting a diversity in the neural mechanisms required for their production. Remarkably, these effects on vocalizations occurred without overt effects on general behavioral measures, and importantly, they occurred within a range of BEC that can be considered risky for humans. Our results suggest that the variable effects of alcohol on finch song reflect differential alcohol sensitivity of the brain circuitry elements that control different aspects of song production. They also point to finches as an informative model for understanding how alcohol affects the neuronal circuits that control the production of learned motor behaviors. PMID:25536524

Olson, Christopher R.; Owen, Devin C.; Ryabinin, Andrey E.; Mello, Claudio V.

2014-01-01

116

Drinking songs: alcohol effects on learned song of zebra finches.  

Science.gov (United States)

Speech impairment is one of the most intriguing and least understood effects of alcohol on cognitive function, largely due to the lack of data on alcohol effects on vocalizations in the context of an appropriate experimental model organism. Zebra finches, a representative songbird and a premier model for understanding the neurobiology of vocal production and learning, learn song in a manner analogous to how humans learn speech. Here we show that when allowed access, finches readily drink alcohol, increase their blood ethanol concentrations (BEC) significantly, and sing a song with altered acoustic structure. The most pronounced effects were decreased amplitude and increased entropy, the latter likely reflecting a disruption in the birds' ability to maintain the spectral structure of song under alcohol. Furthermore, specific syllables, which have distinct acoustic structures, were differentially influenced by alcohol, likely reflecting a diversity in the neural mechanisms required for their production. Remarkably, these effects on vocalizations occurred without overt effects on general behavioral measures, and importantly, they occurred within a range of BEC that can be considered risky for humans. Our results suggest that the variable effects of alcohol on finch song reflect differential alcohol sensitivity of the brain circuitry elements that control different aspects of song production. They also point to finches as an informative model for understanding how alcohol affects the neuronal circuits that control the production of learned motor behaviors. PMID:25536524

Olson, Christopher R; Owen, Devin C; Ryabinin, Andrey E; Mello, Claudio V

2014-01-01

117

Neural correlates of nesting behavior in zebra finches (Taeniopygia guttata).  

Science.gov (United States)

Nest building in birds involves a behavioral sequence (nest material collection and deposition in the nest) that offers a unique model for addressing how the brain sequences motor actions. In this study, we identified brain regions involved in nesting behavior in male and female zebra finches (Taeniopygia guttata). We used Fos immunohistochemistry to quantify production of the immediate early gene protein product Fos (a molecular indicator of neuronal activity) in the brain correlated this expression with the variation in nesting behavior. Using this technique, we found that neural circuitry involved in motor sequencing, social behavior, reward and motivation were active during nesting. Within pairs of nesting birds, the number of times a male picked up or deposited nesting material and the amount of time a female spent in the nest explained the variation in Fos expression in the anterior motor pathway, social behavior network, and reward neural circuits. Identification of the brain regions that are involved in nesting enables us to begin studying the roles of motor sequencing, context, and reward in construction behavior at the neural level. PMID:24508238

Hall, Zachary J; Bertin, Marion; Bailey, Ida E; Meddle, Simone L; Healy, Susan D

2014-05-01

118

Association of Bactericera cockerelli (Homoptera: Psyllidae) with "zebra chip," a new potato disease in southwestern United States and Mexico.  

Science.gov (United States)

A new defect of potato, Solanum tuberosum L., "zebra chip," so named for the characteristic symptoms that develop in fried chips from infected potato tubers, has recently been documented in several southwestern states of the United States, in Mexico, and in Central America. This defect is causing millions of dollars in losses to both potato producers and processors. Zebra chip plant symptoms resemble those caused by potato purple top and psyllid yellows diseases. Experiments were conducted to elucidate the association between the psyllid Bactericera cockerelli (Sulc) (Homoptera: Psyllidae) and zebra chip by exposing clean potato plants to this insect under greenhouse and field conditions. Potato plants and tubers exhibiting zebra chip symptoms were tested for phytoplasmas by polymerase chain reaction. Potato psyllids collected from infected potato fields also were tested. Results indicated that there was an association between the potato psyllid and zebra chip. Plants exposed to psyllids in the greenhouse and field developed zebra chip. In the greenhouse, 25.8 and 59.2% of tubers exhibited zebra chip symptoms in the raw tubers and fried chips, respectively. In the field, 15 and 57% of tubers showed symptoms in raw tubers and chips, respectively. No zebra chip was observed in tubers from plants that had not been exposed to psyllids, either in the greenhouse or field. No phytoplasmas were detected from potato plants or tubers with zebra chip symptoms, suggesting that these pathogens are not involved in zebra chip. Of the 47 samples of potato psyllids tested, only two tested positive for the Columbia Basin potato purple top phytoplasma. PMID:17598522

Munyaneza, J E; Crosslin, J M; Upton, J E

2007-06-01

119

Observations of “zebra” pattern in cm-range with spatial resolution  

Science.gov (United States)

We present the results of the first observations of the solar microwave burst with fine spectral structure of zebra type at the frequency about 5.7 GHz. The burst has been detected simultaneously by the Siberian Solar Radio Telescope and by the spectropolarimeter of the National Astronomical Observatory of China. Zebra pattern consisted of three parallel stripes with complex frequency drift. The degree of circular polarization of emission reached 100%, the polarization sense corresponded to the extraordinary wave (X-mode). We have determined the plasma parameters in the emission source: plasma density about 10 11 cm -3, magnetic field strength 60-80 G. We argue that in the given event the most probable mechanism of the zebra pattern generation is non-linear coupling of harmonics of Bernstein modes.

Altyntsev, Alexander T.; Kuznetsov, Alexey A.; Meshalkina, Natalya S.; Yan, Yihua

120

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

121

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

Science.gov (United States)

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. PMID:19037826

Angarano, Maj-Britt; McMahon, Robert F; Schetz, John A

2009-01-01

122

The Zebra Stripes of the Atacama Desert: Geomorphic Evidence of Quaternary Climate Changes  

Science.gov (United States)

Some hillslopes in the hyperarid region of the Atacama Desert of northern Chile have distinct, contour-parallel bands of sorted surface gravels which we call “zebra stripes” (due to the contrast between the darkly varnished gravels and the light-colored, salt-rich soil). How and when the zebra stripes formed are perplexing questions, particularly since no recorded rainfall seems capable of producing such features. Using GoogleEarth, satellite imagery, field observations, and cosmogenic radionuclides, we have made the first quantitative observations of zebra stripes in order to determine the mechanism and timing of their formation. Possible formation mechanisms include soil shrinking and swelling, seismic shaking, and overland flow, but field observations suggest that overland flow is the most likely. However, calculations based on soil observations and sprinkling experiments on one hillslope suggest that the critical precipitation required to mobilize gravels is much higher than any storm in the historic record. Based on cosmogenic 10Be concentrations in gravels and bedrock, as well as salt deposition rates and concentrations in the soils, we propose that the salt-rich soils began accumulating >0.5-1 Ma, but that the zebra stripes formed later (103-105 ya) on salt-cemented, low-permeability soil. The preservation of the zebra stripe pattern to the present day attests to the prolonged hyperaridity of the Atacama and to the profound climatic change that occurred sometime between the late Pliocene and early Pleistocene. Our work provides initial constraints on zebra stripe formation and timing which may help interpretation of surface deposits in other hyperarid regions on Earth and other planets.

Owen, J. J.; Amundson, R.; Dietrich, W. E.; Nishiizumi, K.; Finkel, R. C.; Chong, G.

2009-12-01

123

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

Directory of Open Access Journals (Sweden)

Full Text Available 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 (lak revealed small locomotor defects associated with the mutation. Using multiclass supervised machine learning, ZebraZoom categorizes 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 73.2-82.5% of cases with four independent experimenters. 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 reaches the level of precision found in manual analysis but accomplishes tasks in a high-throughput format necessary for large screens.

ClaireWyart

2013-06-01

124

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?  

OpenAIRE

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 regulation of transcription and initiation of lytic replication is unknown. Here we show that S173, a residue in the regulatory domain, is obligatory for ZEBRA to function as an origin binding protein but...

El-guindy, Ayman; Heston, Lee; Delecluse, Henri-jacques; Miller, George

2007-01-01

125

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

International Nuclear Information System (INIS)

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.)

126

Optimization of chromeless phase mask by comparing scattering bars with zebra patterns  

Science.gov (United States)

Resolution enhancement technology (RET) refer to techniques that extend the usable resolution of an imaging system without decreasing the wavelength of light or increasing the numerical aperture (NA) of the imaging tool. Off-axis illumination (OAI) and phase shift mask (PSM) are essentially accompanied with optical proximity correction (OPC) for most devices nowadays. In general, these three techniques do not work in isolation and the most aggressive mainstream lithography approaches use combinations of all RETs. In fact, OAI and PSM are essentially useless for typical chip-manufacturing applications unless accompanied by OPC. For low k I imaging, strong OAI such as Quasar or dipole illumination types is the best. We used dipole illumination in this study. By using strong OAI, the amplitude of the 0 th order is decreased and the amplitude of the 1 st order is increased. Chromeless phase lithography (CPL) is one of PSM technologies and CPL mask is the possible solution for small geometry with low mask error enhancement factor (MEEF). CPL uses only 180 degrees phase-shifter on transparent glass without chromium film to define light-shielding region, destructive interference between light transmitted through the 0 degree and 180 degrees regions produces dark images. To obtain the best resolution, proper OPC is required with CPL. While the most common and straightforward application of OPC is to simply move absorber edges on the mask by giving simple mask bias, the interesting and important additional technique is the use of scattering bars. Also, we can use zebra patterns for the transmission control. Mask intensity transmission changes can impact the image quality. Zebra patterns are formed by adding chromium transverse features. The transmission will be controlled by the zebra pattern density. Technology node with ArF source is studied and the mask optimization is found to be a critical. And the linewidth of scattering bars, transmission (using zebra feature) are varied at line and space (L/S) patterns. We used 65 nm node 5 L/S and 45 nm node isolated line pattern. In order to optimize the zebra pattern density, we need to control the line width and pitch of the zebra patterns. For dense line and isolated line, the use of scattering bars and zebra patterns affected target critical dimension. We found out the better process window at dense 65 nm node by comparing the use of scattering bars with zebra patterns. Likewise, we optimized the isolated 45 nm node.

Kang, Hye-Young; Lee, Ji-Eun; Kwak, Eun-A.; Kim, Eun-Jin; Park, Seung-Wook; Kim, Sung-Hyuck; Shin, Dong-Soo; Jeong, HeeJun; Oh, Hye-Keun

2006-03-01

127

Generation of microwave bursts with zebra pattern by nonlinear interaction of Bernstein modes  

Science.gov (United States)

The processes of generation and nonlinear interaction of Bernstein modes are investigated. The physical conditions considered correspond here to the sources of microwave bursts with a zebra pattern. It is shown that the simultaneous generation of plasma waves corresponding to several cyclotron harmonics is possible under these conditions. Nonlinear coupling of plasma waves results in formation of a zebra pattern with a frequency separation between the adjacent stripes close to the electron cyclotron frequency. The emission is confined in the narrow angle interval near the transversal (relative to the magnetic field) propagation direction. Polarization of emission in this process corresponds to the extraordinary wave, and the polarization degree reaches 100%.

Kuznetsov, A. A.

2005-07-01

128

Basilar papilla of the canary and zebra finch: A quantitative scanning electron microscopical description  

OpenAIRE

Morphological parameters of the apical surface of canary and zebra finch basilar papillae were quantitatively evaluated by scanning electron microscopy. The papillar length is 1.6 mm in both species. The zebra-finch papilla has a larger number of hair cells and is wider in the apical half of the papilla as compared to the canary. These two small songbird species have the smallest number of hair cells and the smallest papillae of the bird species investigated to date. The orientation of the ha...

Gleich, Otto; Manley, Geoffrey A.; Mandl, Alexandra; Dooling, Robert J.

1994-01-01

129

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

OpenAIRE

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 70...

Yu, Sijie; Nakariakov, V. M.; Selzer, L. A.; Tan, Baolin; Yan, Yihua

2013-01-01

130

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

OpenAIRE

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 birds dilate. This is called cold-induced vasodilation CIVD. The Zebra finches were anesthetized with isoflurane and the brood patch was stimulated with a cooling probe set at 20-21 °C. Differences in...

Klubb, Sofia

2010-01-01

131

Molecular approaches to understanding variation in reproductive phenotype of female zebra finches (Taeniopygia guttata)  

OpenAIRE

I investigated inter-individual variation at the cell and molecular level in relation to reproductive phenotype (egg and clutch size, timing of laying) in female zebra finches (Taeniopygia guttata). First, I developed an antibody against zebra finch apoVLDL-II. I then developed a dot-blot assay to quantify plasma apoVLDL-II levels. This revealed marked inter-individual variation in apoVLDL-II levels but this was not correlated with differences in reproductive phenotype. Second, I described va...

Han, Dong

2008-01-01

132

A Dose-Response Study of Estradiol's Effects on the Developing Zebra Finch Song System  

OpenAIRE

To gauge the sensitivity of the female zebra finch song system to estradiol (E2), we used subcutaneous implants to administer various doses of E2 to hatchling female zebra finches. Four different doses of E2 were administered: 50, 15, 5 and 0 ?g via subcutaneous silicon “ropes” at hatching, and the brains were examined in adulthood. Further, we examined whether masculinization was all-or-none once a threshold was reached or if the morphology of the song system would show a graded respons...

Grisham, William; Lee, Janet; Park, Sun Hee; Mankowski, Jennifer L.; Arnold, Arthur P.

2008-01-01

133

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

OpenAIRE

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-wavelengt...

Chen, Bin; Bastian, Timothy S.; Gary, Dale E.; Jing, Ju

2011-01-01

134

Sexual Dimorphism in the Early Embryogenesis in Zebra Finches  

Science.gov (United States)

Sex-specific gene expression before the onset of gonadogensis has been documented in embryos of mammals and chickens. In several mammalian species, differences in gene expression are accompanied by faster growth of pre-implantation male embryos. Here we asked whether avian embryos before gonadal differentiation are also sex-dimorphic in size and what genes regulate their growth. We used captive zebra finches (Taeniopygia guttata) whose freshly laid eggs were artificially incubated for 36–40 hours. Analyses controlling for the exact time of incubation of 81 embryos revealed that males were larger than females in terms of Hamburger and Hamilton stage and number of somites. Expression of 15 genes involved in cell cycle regulation, growth, metabolic activity, steroidogenic pathway and stress modulation were measured using RT-PCR in 5 male and 5 female embryos incubated for exactly 36 h. We found that in the presence of equal levels of the growth hormone itself, the faster growth of male embryos is most likely achieved by the overexpression of the growth hormone receptor gene and three other genes responsible for cell cycle regulation and metabolism, all of them located on the Z chromosome. Autosomal genes did not show sex-specific expression, except for the steroidogenic factor 1 which was expressed only in female embryos. To our knowledge this is the first report of sexual size dimorphism before gonadogenesis in birds. The finding suggests that faster growth of early male embryos is conserved through the mammalian and bird phyla, irrespective of their differential sex chromosome systems. PMID:25493645

Tagirov, Makhsud; Rutkowska, Joanna

2014-01-01

135

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

OpenAIRE

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. Virol. 72:4543-4551, 1999). We investigated whether phosphorylation of ZEBRA protein at this site by a serine-threonine protein kinase was required for activation of an early lytic cycle viral ge...

El-guindy, Ayman S.; Heston, Lee; Endo, Yoshimi; Cho, Myung-sam; Miller, George

2002-01-01

136

Phenotypic and Etiological Differences Between Psyllid Yellows and Zebra Chip Diseases of Potatoes  

Science.gov (United States)

Both potato psyllid yellows and Zebra chip (ZC) potato diseases are associated with the potato psyllid, Bactericera cockerelli (Sulc). Aboveground plant symptoms of both diseases are similar but there is a difference in symptoms in potato tubers. ZC has recently been associated with a new species o...

137

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

138

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

139

Molecular cloning and characterization of the germline-restricted chromosome sequence in the zebra finch.  

Science.gov (United States)

The zebra finch (Taeniopygia guttata) germline-restricted chromosome (GRC) is the largest chromosome and has a unique system of transmission in germ cells. In the male, the GRC exists as a single heterochromatic chromosome in the germline and is eliminated from nuclei in late spermatogenesis. In the female, the GRC is bivalent and euchromatic and experiences recombination. These characteristics suggest a female-specific or female-beneficial function of the GRC. To shed light on the function of GRC, we cloned a portion of the GRC using random amplified polymorphic DNA-polymerase chain reaction and analyzed it using molecular genetic and cytogenetic methods. The GRC clone hybridized strongly to testis but not blood DNA in genomic Southern blots. In fluorescent in situ hybridization analysis on meiotic chromosomes from synaptonemal complex spreads, the probe showed hybridization across a large area of the GRC, suggesting that it contains repetitive sequences. We isolated a sequence homologous to the GRC from zebra finch chromosome 3 and a region of chicken chromosome 1 that is homologous to zebra finch chromosome 3; the phylogenetic analysis of these three sequences suggested that the GRC sequence and the zebra finch chromosome 3 sequence are most closely related. Thus, the GRC sequences likely originated from autosomal DNA and have evolved after the galliform-passeriform split. The present study provides a foundation for further study of the intriguing GRC. PMID:19452161

Itoh, Yuichiro; Kampf, Kathy; Pigozzi, María Inés; Arnold, Arthur P

2009-08-01

140

A Generalizability Analysis of Subjective Personality Assessments in the Stumptail Macaque and the Zebra Finch.  

Science.gov (United States)

Two longitudinal studies involving 29 raters concerning the construct validity, temporal stability, and interrater reliability of the latent common factors underlying subjective assessments by human raters of personality traits in the stumptail macaque and the zebra finch illustrate the use of generalizability analysis to test prespecified…

Figueredo, Aurelio Jose; And Others

1995-01-01

141

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

142

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

143

Ipsilaterally evoked responses of the zebra finch visual wulst are reduced during ontogeny  

OpenAIRE

Visual wulst responses to ipsi- and contralateral visual stimuli were investigated in young zebra finches (Taeniopygia guttata castanotis Gould) of different ages. Contralateral responses in 20, 40, 60 and 80 day old birds do not differ significantly from those in adults. In contrast, ipsilateral responses decrease substantially during development and become very weak and irregular in adult birds.

Bredenko?tter, Manfred; Bischof, Hans-joachim

1990-01-01

144

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...

145

Evidence that Cell Death is Associated with Zebra Chip Disease in Potato Tubers  

Science.gov (United States)

Zebra chip (ZC) is an established and highly destructive disease of potato (Solanum tuberosum L.) that occurs in several southwestern states of the United States, Mexico, Central America, and New Zealand. The causal agent for this disease has not been identified. However, the bacterium ‘Candidatus ...

146

The Quantitative Ethology of the Zebra Finch: A Study in Comparative Psychometrics.  

Science.gov (United States)

A quantitative ethogram was developed for the zebra finch, using one-zero focal animal sampling on an ethologically comprehensive checklist of 52 behavioral items, and it was assessed for interobserver reliability and construct validity. Applying the quantitative methods of psychometrics allows verification of ethological theory and testing of…

Figueredo, Aurelio Jose; And Others

1992-01-01

147

Inter-birth interval in zebras is longer following the birth of male foals than after female foals  

Science.gov (United States)

Mammalian reproductive rates vary among individuals for physiological and environmental reasons. This study aims to determine reproductive rates from an individually monitored population of wild Plains zebras Equus quagga, and to assess the sources of variability in inter-birth intervals. The animals were monitored, where possible, every six months from 2004 to 2011. Thirty nine intervals corresponding to 65 births in 26 mares were identified, using direct observations and faecal steroid monitoring. Mean foaling rate of the population is 0.74 foal/year, and comparable with the literature. There was no significant effect of mother's age, nor of the season of previous birth on the length of inter-birth intervals. Inter-birth interval was significantly longer when the first foal was a male. This finding indicates that additional costs of having a son may delay future reproduction and thus reduce the total number of offspring a mare can have during her lifetime. Individually-based data provide critical information on the determinants of reproductive rates, and are therefore a key to understanding the causes of variations in life-history traits.

Barnier, Florian; Grange, Sophie; Ganswindt, Andre; Ncube, Hlengisizwe; Duncan, Patrick

2012-07-01

148

Early responses to zebra mussels in the Great Lakes: a journey from information vacuum to policy and regulation  

Science.gov (United States)

Invasive species such as zebra mussels pose a threat to the economies and environments of coastal and fresh-water habitats around the world. Consequently, it is important that government policies and programs be adequate to protect these waters from invaders. This chapter documents key events that took place in the early years (1988-1991) of zebra mussel colonization of the Laurentian Great Lakes and evaluates government responses (policies and programs) to this disruptive, invasive, freshwater species.

Griffiths, Ronald W.; Schloesser, Don W.; Kovalak, William P.

2013-01-01

149

Sexually Dimorphic SCAMP1 Expression in the Forebrain Motor Pathway for Song Production of Juvenile Zebra Finches  

OpenAIRE

Mechanisms regulating sexual differentiation of the zebra finch song system are not well understood. The present study was designed to more fully characterize secretory carrier membrane protein 1 (SCAMP1), which was identified in a cDNA microarray screen as showing increased expression in the forebrains of developing male compared with female zebra finches. We completed the sequence of the open reading frame and used in situ hybridization to compare mRNA in song control regions of juvenile (2...

Tang, Yu Ping; Peabody, Camilla; Tomaszycki, Michelle L.; Wade, Juli

2007-01-01

150

Assessing short- and long-term repeatability and stability of personality in captive zebra finches using longitudinal data  

OpenAIRE

Assessing behavioural consistency is crucial to understand the evolution of personality traits. In the present study we examined the short- and long-term repeatability and stability of two unrelated personality traits—exploratory tendencies and struggling rate—using captive female zebra finches (Taeniopygia guttata). We performed two experimental sessions of behavioural tests with a seven-month interval, which represents up to one quarter of a zebra finch's life expectancy. We showed that...

David, Morgan; Auclair, Yannick; Cezilly, Frank

2012-01-01

151

On the production and perception of syntactical regularities in zebra finches : experimenting with ABBA, ACDC and others  

OpenAIRE

Natural zebra finch song contains heterogeneity in the relative distribution of element types across 13 populations worldwide, but compared between individuals it contains relatively little structural constraints or rules in the order of elements. In contrast, from a perception point of view, zebra finches are able to detect differences in song structure and are able to learn rules to generalize these regularities to new element types in some instances, a hallmark of human language. This abil...

Heijningen, Cornelia Adriana Anna

2012-01-01

152

The sensitive period for the morphological effects of monocular deprivation in two nuclei of the tectofugal pathway of zebra finches  

OpenAIRE

Previous experiments with 2-deoxyglucose (2-DG) suggested the existence of a critical previous termperiodnext term for the effects of monocular deprivation in the nucleus rotundus of zebra finches. The present study concerns the time course of this sensitive period for the morphological effects of monocular deprivation in two areas of the tectofugal visual pathway of zebra finches, the nucleus rotundus of the thalamus and the telencephalic ectostriatum. Cell size and volume changes were measu...

Herrmann, Kathrin; Bischof, Hans-joachim

1988-01-01

153

Smooth operator: Avoidance of subharmonic bifurcations through mechanical mechanisms simplifies song motor control in adult zebra finches  

OpenAIRE

Like human infants, songbirds acquire their song by imitation and eventually generate sounds that result from complicated neural networks and intrinsically nonlinear physical processes. Signatures of low-dimensional chaos such as subharmonic bifurcations have been reported in adult and developing zebra finch song. Here, we use methods from nonlinear dynamics to test whether adult male zebra finches (Taenopygia guttata) use the intrinsic nonlinear properties of their vocal organ, the syrinx, t...

Elemans, Coen P. H.; Laje, Rodrigo; Mindlin, Gabriel B.; Goller, Franz

2011-01-01

154

Ultrastructural effects of monocular deprivation in the neuropil of nucleus rotundus in the zebra finch: a quantitative electron microscopic study  

OpenAIRE

Ultrastructural effects of monocular deprivation starting at hatching have been studied in the neuropil of nucleus rotundus, the thalamic visual relay station of the tectofugal pathway in birds. Synaptic density, presynaptic terminal size, and length of postsynaptic density (PSD) have been quantified in juvenile (20-day) and adult (100-day) zebra finches. These parameters are mature in 20-day-old zebra finches when reared under normal conditions. Alterations obtained by monocular deprivation ...

Nixdorf, Barbara; Bischof, Hans-joachim

1987-01-01

155

Evaluation of Octhylphenol Effect on Development and Survival on Zebra Fish (Danio Rerio) During Different Ontogenic Period  

OpenAIRE

This paper is part of a complex study of our research collective that studies the toxic effect of the ethinylestradiolum, and some of the polyethoxylated alkylphenols on the growth and reproduction of the Zebra fish (Danio rerio) and of the common Carp (Cyprinus carpio). Our study aim was to evaluate the effect of octylphenol on growth and survival of zebra fish, from 21-115 days

Gabi Dumitrescu; Liliana Petculescu Ciochina; Sorin Voia; Dorel Dronca; Liliana Boca

2010-01-01

156

Alteration of a single serine in the basic domain of the Epstein-Barr virus ZEBRA protein separates its functions of transcriptional activation and disruption of latency.  

OpenAIRE

The ZEBRA protein from Epstein-Barr virus (EBV) activates a switch from the latent to the lytic expression program of the virus. ZEBRA, a member of the bZIP family of DNA-binding proteins, is a transcriptional activator capable of inducing expression from viral lytic cycle promoters. It had previously been thought that ZEBRA's capacity to disrupt EBV latency resided primarily in its ability to activate transcription of genes that encode products required for lytic replication. We generated a ...

Francis, A. L.; Gradoville, L.; Miller, G.

1997-01-01

157

High-Throughput Selection of Retrovirus Producer Cell Lines Leads to Markedly Improved Efficiency of Germ Line-Transmissible Insertions in Zebra Fish  

OpenAIRE

Vesicular stomatitis virus glycoprotein G-pseudotyped mouse retroviral vectors have been used as mutagens for a large-scale insertional mutagenesis screen in the zebra fish. To reproducibly generate high-titer virus stocks, we devised a method for rapidly selecting cell lines that can yield high-titer viruses and isolated a producer cell line that yields virus at a high titer on zebra fish embryos. Virus produced from this line, designated GT virus, is nontoxic following injection of zebra fi...

Chen, Wenbiao; Burgess, Shawn; Golling, Greg; Amsterdam, Adam; Hopkins, Nancy

2002-01-01

158

Comparing regions of the Epstein-Barr virus ZEBRA protein which function as transcriptional activating sequences in Saccharomyces cerevisiae and in B cells.  

OpenAIRE

The ZEBRA protein activates expression of Epstein-Barr virus early-lytic-cycle genes in human B lymphocytes. Here it is shown that ZEBRA also behaves as a sequence-specific transcriptional activator in Saccharomyces cerevisiae. Deletional mutagenesis defined three regions of ZEBRA that participate in activation in S. cerevisiae. These regions are designated YI (amino acids [aa] 1 to 25), YII (aa 51 to 102), and YIII (aa 228 to 245). Two of the three regions of the native ZEBRA protein act tog...

Miller, G.; Himmelfarb, H.; Heston, L.; Countryman, J.; Gradoville, L.; Baumann, R.; Chi, T.; Carey, M.

1993-01-01

159

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

160

Loss-Cone Instability and Formation of Zebra Patterns in Type IV Solar Radio Bursts  

Science.gov (United States)

The loss-cone instability of energetic electrons at double plasma resonance is considered. Conditions required for the formation of a zebra pattern in type IV solar radio bursts are determined. It is shown that electrons with a power-law energetic spectrum can effectively excite upper-hybrid waves at double plasma resonance. Stripes of a zebra pattern become more pronounced with an increase of the loss-cone opening angle and the power-law spectral index. The growth rate at the resonance frequencies decreases with an increase of the cyclotron harmonic number. Interpretation of observations and diagnostics of plasma for the April 21, 2002, event are performed. Conclusions about the impulsive mode of injection of energetic electrons into a coronal arc are made.

Kuznetsov, A. A.; Tsap, Yu. T.

2007-03-01

161

Statistics and Classification of the Microwave Zebra Patterns Associated with Solar Flares  

CERN Document Server

The microwave zebra pattern (ZP) is the most interesting, intriguing, and complex spectral structure frequently observed in solar flares. A comprehensive statistical study will certainly help us to understand the formation mechanism, which is not exactly clear now. This work presents a comprehensive statistical analysis on a big sample with 202 ZP events collected from observations at the Chinese Solar Broadband Radio Spectrometer at Huairou and the Ondrejov Radiospectrograph in Czech Republic at frequencies of 1.00 - 7.60 GHz during 2000 - 2013. After investigating the parameter properties of ZPs, such as the occurrence in flare phase, frequency range, polarization degree, duration, etc., we find that the variation of zebra stripe frequency separation with respect to frequency is the best indicator for a physical classification of ZPs. Microwave ZPs can be classified into 3 types: equidistant ZP, variable-distant ZP, and growing-distant ZP, possibly corresponding to mechanisms of Bernstein wave model, whistl...

Tan, Baolin; Zhang, Yin; Meszarosova, H; Karlicky, M

2013-01-01

162

Pharyngeal teeth of the freshwater drum (Aplodinotus grunniens) a predator of the zebra mussel (Dreissena polymorpha)  

Science.gov (United States)

The morphology of pharyngeal teeth of freshwater drum (Aplodinotus grunniens) was studied to determine changes that occur during growth of drum that may relate to consumption of zebra mussel (Dreissena polymorpha) by larger fish. Pharyngeal teeth were of three types. Cardiform teeth were replaced by villiform teeth, which were replaced by molariform teeth as the size class of drum increased. Molariform teeth comprised over 85% of total surface area of dentition in fish 265 mm long.

French, John R. P., III

1997-01-01

163

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

OpenAIRE

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 major challenge due to low selectivity over non-target organisms and the expense of the large quantities of biocides required. A novel delivery technique involving the encapsulation of a toxin within h...

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

2011-01-01

164

Analysis of time-of-flight spectrum measurements in some Zebra plutonium assemblies  

International Nuclear Information System (INIS)

Time-of-flight measurements of the core centre neutron spectrum have been made on four plutonium fuelled assemblies in the Zebra reactor. The subcritical reactor was pulsed by the 14 MeV linear accelerator recently installed on the reactor. The various correction factors required to interpret the beam measurement are considered and error assignments are made. The measured spectra are finally compared with predictions using the MURAL code and FGL4 data set. (author)

165

Interference Mechanism of ``Zebra-Pattern'' Formation in Solar Radio Emission  

Science.gov (United States)

It is shown that “zebra-pattern” in solar continuum events (in type IV bursts) can be formed as a result of interference between direct and reflected rays coming from a source of small size in a stratified atmosphere. The emission is generated by plasma mechanism. Full emission flux is contributed from a great number of narrow-band short-lived sources of small sizes, which are formed by plasma waves captured in density minima of background plasma fluctuations.

Ledenev, V. G.; Yan, Y.; Fu, Q.

2006-01-01

166

New records of 43 spider species from the Mountain Zebra National Park, South Africa (Arachnida: Araneae)  

OpenAIRE

This study forms part of the South African National Survey of Arachnida (SANSA), initiated in 1997 with the main aim to create an inventory of the arachnid fauna of South Africa (Dippenaar-Schoeman & Craemer 2000). One of the objectives of SANSA is to assess the number of arachnid species presently protected in conserved areas in the country. Check lists of spiders are now available for three national parks, three nature reserves and a conservancy. These areas include: Mountain Zebra ...

Dippenaar-schoeman, A. S.

2006-01-01

167

EFFECTS OF ORGANOPHOSPHATES ON ACUTE POISONING AND ACETYL CHOLINESTERASE INHIBITION IN ZEBRA FISH  

OpenAIRE

Organophosphates (Ops.) are the most widely used insecticides available today. These are a group of insecticides used in chemical sprays to kill bugs, and insects in orchards, vineyards, vegetables and cereal crops. The present study examined effects of the pesticide Methyl parathion, Dichlorvos and Chlorpyrifos on adult zebra fish were exposed to various concentrations (5, 10 & 25mg/L) for 24 and 48hrs acute toxic study. Chlorpyrifos showed mortality in all concentrations and Methyl para...

Th Mv, Sukirtha Usharani

2013-01-01

168

Molecular cloning and characterization of the germline-restricted chromosome sequence in the zebra finch  

OpenAIRE

The zebra finch (Taeniopygia guttata) germline-restricted chromosome (GRC) is the largest chromosome and has a unique system of transmission in germ cells. In the male, the GRC exists as a single heterochromatic chromosome in the germline and is eliminated from nuclei in late spermatogenesis. In the female, the GRC is bivalent and euchromatic and experiences recombination. These characteristics suggest a female-specific or female-beneficial function of the GRC. To shed light on the function o...

Itoh, Yuichiro; Kampf, Kathy; Pigozzi, Mari?a Ine?s; Arnold, Arthur P.

2009-01-01

169

Multi-functional foot use during running in the zebra-tailed lizard (Callisaurus draconoides)  

OpenAIRE

A diversity of animals that run on solid, level, flat, non-slip surfaces appear to bounce on their legs; elastic elements in the limbs can store and return energy during each step. The mechanics and energetics of running in natural terrain, particularly on surfaces that can yield and flow under stress, is less understood. The zebra-tailed lizard (Callisaurus draconoides), a small desert generalist with a large, elongate, tendinous hind foot, runs rapidly across a variety of ...

Li, Chen; Hsieh, S. Tonia; Goldman, Daniel I.

2013-01-01

170

Developmental changes in estrogen-sensitive neurons in the forebrain of the zebra finch.  

OpenAIRE

The brain areas for the control of song are sexually dimorphic in the zebra finch (Poephila guttata). Implantation of estrogen in young females within the first 40 days after hatching masculinizes their brain song areas. Monoclonal antibody (H222Sp gamma) against the estrogen receptor was used for the localization of estrogen-target cells in the brain. The nucleus hyperstriatum ventrale, pars caudale, was the only song control area that contained cells with estrogen-receptor sites. The number...

Gahr, M.; Konishi, M.

1988-01-01

171

Testosterone facilitates some conspecific song discriminations in castrated zebra finches (Taeniopygia guttata).  

OpenAIRE

An experiment was designed to test for the influence of testosterone on song discriminations. We found that testosterone did have an effect, which interacted with practice and the nature of the stimuli. Fourteen adult castrated zebra finches (Taeniopygia guttata) were grouped into seven pairs. In each pair, one bird was implanted with a testosterone-filled silastic tube and the other was implanted with an empty silastic tube. They were then trained on a go/no-go operant task to discriminate b...

Cynx, J.; Nottebohm, F.

1992-01-01

172

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

OpenAIRE

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 indicate several processing steps between primary sensory areas of the telencephalon and HVC. Within HVc, under these experimental conditions no interaction between acoustic and visual input could...

Bischof, Hans-joachim; Engelage, Ju?rgen

1985-01-01

173

Juvenile zebra finches can use multiple strategies to learn the same song  

OpenAIRE

Does the ontogeny of vocal imitation follow a set program that, given a target sound, unfolds in a predictable manner, or is it more like problem solving, with many possible solutions? We report that juvenile male zebra finches, Taeniopygia guttata, can master their imitation of the same song in various ways; these developmental trajectories are sensitive to the social setting in which the bird grows up. A variety of vocal developmental trajectories have also been described in infants. Are th...

Liu, Wan-chun; Gardner, Timothy J.; Nottebohm, Fernando

2004-01-01

174

Functional MRI of the zebra finch brain during song stimulation suggests a lateralized response topography  

OpenAIRE

Electrophysiological and activity-dependent gene expression studies of birdsong have contributed to the understanding of the neural representation of natural sounds. However, we have limited knowledge about the overall spatial topography of song representation in the avian brain. Here, we adapt the noninvasive functional MRI method in mildly sedated zebra finches (Taeniopygia guttata) to localize and characterize song driven brain activation. Based on the blood oxygenation level-dependent sig...

Voss, Henning U.; Tabelow, Karsten; Polzehl, Jo?rg; Tchernichovski, Ofer; Maul, Kristen K.; Salgado-commissariat, Delanthi; Ballon, Douglas; Helekar, Santosh A.

2007-01-01

175

Rearing conditions affect neuron morphology in a telencephalic area of the zebra finch  

OpenAIRE

THE morphology of ANC (Archi-neostriatum caudale) neurons in zebra finches is affected by arousal and rearing conditions. Branching index and spine density of ANC neurons are decreased in isolated birds and enhanced in cage reared animals, compared to aviary reared animals. Chasing the birds around the cage, or seven days of social contact with a female, raises these indices in birds isolated until adulthood relative to those of the aviary reared animals. We conclude that branching index and ...

Rollenhagen, Astrid; Bischof, Hans-joachim

1991-01-01

176

Diet, maternal condition, and offspring sex ratio in the zebra finch, Poephila guttata  

OpenAIRE

Where maternal condition affects condition and reproductive potential of offspring differentially with respect to sex, mothers in relatively good condition should produce more of the sex whose fitness is more dependent on condition. We experimentally manipulated body-condition in unmated zebra finches by feeding them for three months on high- or low-quality diets. Birds were then allowed to breed, while keeping the same diets. Females on the lower quality diet were in better condition and hat...

Bradbury, R. B.; Blakey, J. K.

1998-01-01

177

Sexual imprinting in female zebra finches: changes in preferences as an effect of adult experience  

OpenAIRE

It has been shown that sexual imprinting in male zebra finches can be seen as a two stage process with an early acquisition period, where a sexual preference is established, and a consolidation process, where the early acquired preference is linked to sexual behaviour and stabilized. The consolidation process can, by the appropriate experimental design, be delayed until adulthood. In the course of consolidation, the initial preference for the foster species can be altered by exposure to a fem...

Oetting, Sabine; Bischof, Hans-joachim

1996-01-01

178

Male phenotype and ejaculate quality in the zebra finch Taeniopygia guttata  

OpenAIRE

We tested the idea that female preference for relatively attractive extra-pair males arises because the morphological and behavioural features that females find attractive covary with ejaculate features: Sheldon's (Proc. R. Soc. Lond. B 257 25-30 (1994)) phenotype-linked fertility insurance hypothesis. Two phenotypic traits that female zebra finches find attractive in males are song rate and symmetry of chest band plumage, but we found neither of these to be significantly related to any of th...

Birkhead, T. R.; Fletcher, F.

1995-01-01

179

Altered Auditory BOLD Response to Conspecific Birdsong in Zebra Finches with Stuttered Syllables  

OpenAIRE

How well a songbird learns a song appears to depend on the formation of a robust auditory template of its tutor's song. Using functional magnetic resonance neuroimaging we examine auditory responses in two groups of zebra finches that differ in the type of song they sing after being tutored by birds producing stuttering-like syllable repetitions in their songs. We find that birds that learn to produce the stuttered syntax show attenuated blood oxygenation level-dependent (BOLD) responses to t...

Voss, Henning U.; Salgado-commissariat, Delanthi; Helekar, Santosh A.

2010-01-01

180

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

OpenAIRE

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. Males discriminating between their own and another song from their own aviary reached criterion in the fewest number of trials, followed by males discriminating between two songs from their own aviar...

Cynx, J.; Nottebohm, F.

1992-01-01

181

Contralateral projections of the optic tectum in the zebra finch (Taeniopygia guttata castanotis)  

OpenAIRE

Efferent projections of the optic tectum of zebra finches were investigated by injection of the radioactive anterograde tracer 3H-proline. In addition to a variety of ipsilateral projections, some contralateral connections were found. Quantitative evaluation of the recrossing tecto-rotundal and nucleus subpraetactalis/nucleus interstitio-praetecto-subpraetactalis projection revealed that these connections are much stronger than previously believed. In contrast, the tecto-tectal projection is ...

Bischof, Hans-joachim; Niemann, Jutta

1990-01-01

182

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

OpenAIRE

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 learning, during which the young individuals memorize the vocalizations of adult conspecifics to which they are exposed. After this memorization phase, vocal learning proceeds through a sensorimoto...

Gobes, S. M. H.

2009-01-01

183

Maternal Effects Underlie Ageing Costs of Growth in the Zebra Finch (Taeniopygia guttata).  

OpenAIRE

Maternal effects provide a mechanism to adapt offspring phenotype and optimize the mother's fitness to current environmental conditions. Transferring steroids to the yolk is one way mothers can translate environmental information into potential adaptive signals for offspring. However, maternally-derived hormones might also have adverse effects for offspring. For example, recent data in zebra finch chicks suggested that ageing related-processes (i.e. oxidative stress and telomere loss) were in...

Tissier, Mathilde L.; Williams, Tony D.; Criscuolo, Franc?ois

2014-01-01

184

Song Decrystallization in Adult Zebra Finches Does Not Require the Song Nucleus NIf  

OpenAIRE

In adult male zebra finches, transecting the vocal nerve causes previously stable (i.e., crystallized) song to slowly degrade, presumably because of the resulting distortion in auditory feedback. How and where distorted feedback interacts with song motor networks to induce this process of song decrystallization remains unknown. The song premotor nucleus HVC is a potential site where auditory feedback signals could interact with song motor commands. Although the forebrain nucleus interface of ...

Roy, Arani; Mooney, Richard

2009-01-01

185

Early exposure leads to repeatable preferences for male song in female zebra finches.  

OpenAIRE

This study addressed the question of how early learning processes in females influence later preferences for a male trait. I tested whether exposure to song alone (of a male other than the father) was sufficient for inducing a stable (repeatable) preference in female zebra finches (Taeniopygia guttata) by limiting early exposure to tape tutoring. A group of controls heard no songs before also being tested in adulthood. Repeated tests for preferences for tutor or unfamiliar song were made, int...

Riebel, K.

2000-01-01

186

Sex-specific effects of yolk testosterone on survival, begging and growth of zebra finches  

OpenAIRE

Yolk androgens affect offspring hatching, begging, growth and survival in many bird species. If these effects are sex-specific, yolk androgen deposition may constitute a mechanism for differential investment in male and female offspring. We tested this hypothesis in zebra finches. In this species, females increase yolk-testosterone levels and produce male-biased sex ratios when paired to more attractive males. We therefore predicted that especially sons benefit from elevated yolk androgens. E...

Von Engelhardt, Nikolaus; Carere, Claudio; Dijkstra, Cor; G G Groothuis, Ton

2006-01-01

187

Vocal imitation in zebra finches is inversely related to model abundance  

OpenAIRE

A juvenile male zebra finch, Taeniopygia guttata, kept singly with its father develops a fairly complete imitation of the father’s song. The imitation is less complete when other male siblings are present, possibly because as imitation commences, model abundance increases. Here we examine the consequences of allowing more or less access to a song model. Young males heard a brief song playback when they pecked at a key, but different males were allowed to hear different numbers of playbacks ...

Tchernichovski, Ofer; Lints, Thierry; Mitra, Partha P.; Nottebohm, Fernando

1999-01-01

188

Functional testicular tissue does not masculinize development of the zebra finch song system.  

OpenAIRE

Current theories of sexual differentiation maintain that ovarian estrogen prevents masculine development of the copulatory system in birds, whereas estrogen derived from testicular androgens promotes masculine sexual differentiation of neuroanatomy and sexual behavior in mammals. Paradoxically, some data suggest that the neural song system in zebra finches follows the mammalian pattern with estrogenic metabolites of testicular secretions causing masculine development. To test whether the remo...

Wade, J.; Arnold, A. P.

1996-01-01

189

Monocular deprivation affects neuron size in the ectostriatum of the zebra finch brain  

OpenAIRE

The effects of different periods of monocular deprivation on cell sizes in the ectostriatum, the telencephalic relay of the tectofugal pathway in zebra finches, were evaluated. Following 20 days of monocular closure, neurons in the deprived and undeprived hemisphere show an unselective hypertrophy of 10%. Extending the deprivation period results in a shrinkage of neurons of the deprived side to values of adult normally reared birds, whereas the non-deprived neurons maintain their hypertrophie...

Herrmann, Kathrin; Bischof, Hans-joachim

1986-01-01

190

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

OpenAIRE

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 d...

ClaireWyart; OlivierMirat; JennaRenéeSternberg

2013-01-01

191

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

OpenAIRE

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: z...

Alina Krevš; Ri?ardas Paškauskas; Anastasija Zaiko

2010-01-01

192

Statistics and Classification of the Microwave Zebra Patterns Associated with Solar Flares  

OpenAIRE

The microwave zebra pattern (ZP) is the most interesting, intriguing, and complex spectral structure frequently observed in solar flares. A comprehensive statistical study will certainly help us to understand the formation mechanism, which is not exactly clear now. This work presents a comprehensive statistical analysis on a big sample with 202 ZP events collected from observations at the Chinese Solar Broadband Radio Spectrometer at Huairou and the Ondrejov Radiospectrograp...

Tan, Baolin; Tan, Chengming; Zhang, Yin; Meszarosova, H.; Karlicky, M.

2013-01-01

193

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

OpenAIRE

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 amplifyi...

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

2011-01-01

194

Space as a limiting resource among sessile benthic invertebrates: Zebra mussels, freshwater sponges and bryozoans  

OpenAIRE

Four species of freshwater sponges (Porifera) and four species of bryozoans (Bryozoa) were identified from six southern Lake Michigan harbors growing in association with the recently introduced zebra mussel (Dreissena polymorpha). Most hard substrates found within the harbors, including wooden pier posts, steel revetment walls, and stone rip-rap, were completely covered by these sessile benthic organisms, suggesting attachment space was a limiting resource. Sponges prefer vertical or overhang...

Lauer, Thomas Edward

1997-01-01

195

Sexual differentiation of the zebra finch song system: potential roles for sex chromosome genes  

OpenAIRE

Abstract Background Recent evidence suggests that some sex differences in brain and behavior might result from direct genetic effects, and not solely the result of the organizational effects of steroid hormones. The present study examined the potential role for sex-biased gene expression during development of sexually dimorphic singing behavior and associated song nuclei in juvenile zebra finches. Results A microarray screen revealed more than 2400 putative gene...

Clayton David F; Replogle Kirstin; Peabody Camilla; Tomaszycki Michelle L; Tempelman Robert J; Wade Juli

2009-01-01

196

Estradiol and song affect female zebra finch behavior independent of dopamine in the striatum  

OpenAIRE

Female songbirds display preferences for certain song characteristics, but the neural and hormonal mechanisms mediating these preferences are not fully clear. The present study sought to further explore the role of estradiol, as well as assess potential roles of dopaminergic systems, on behavioral responses to song. Adult female zebra finches were treated with estradiol and exposed to tutored or untutored song or silence. Behavior was quantified and neurochemistry of the nucleus accumbens and...

Svec, Lace A.; Lookingland, Keith J.; Wade, Juli

2009-01-01

197

Zebra finch mates use their forebrain song system in unlearned call communication.  

Science.gov (United States)

Unlearned calls are produced by all birds whereas learned songs are only found in three avian taxa, most notably in songbirds. The neural basis for song learning and production is formed by interconnected song nuclei: the song control system. In addition to song, zebra finches produce large numbers of soft, unlearned calls, among which "stack" calls are uttered frequently. To determine unequivocally the calls produced by each member of a group, we mounted miniature wireless microphones on each zebra finch. We find that group living paired males and females communicate using bilateral stack calling. To investigate the role of the song control system in call-based male female communication, we recorded the electrical activity in a premotor nucleus of the song control system in freely behaving male birds. The unique combination of acoustic monitoring together with wireless brain recording of individual zebra finches in groups shows that the neuronal activity of the song system correlates with the production of unlearned stack calls. The results suggest that the song system evolved from a brain circuit controlling simple unlearned calls to a system capable of producing acoustically rich, learned vocalizations. PMID:25313846

Ter Maat, Andries; Trost, Lisa; Sagunsky, Hannes; Seltmann, Susanne; Gahr, Manfred

2014-01-01

198

Castration modulates singing patterns and electrophysiological properties of RA projection neurons in adult male zebra finches.  

Science.gov (United States)

Castration can change levels of plasma testosterone. Androgens such as testosterone play an important role in stabilizing birdsong. The robust nucleus of the arcopallium (RA) is an important premotor nucleus critical for singing. In this study, we investigated the effect of castration on singing patterns and electrophysiological properties of projection neurons (PNs) in the RA of adult male zebra finches. Adult male zebra finches were castrated and the changes in bird song assessed. We also recorded the electrophysiological changes from RA PNs using patch clamp recording. We found that the plasma levels of testosterone were significantly decreased, song syllable's entropy was increased and the similarity of motif was decreased after castration. Spontaneous and evoked firing rates, membrane time constants, and membrane capacitance of RA PNs in the castration group were lower than those of the control and the sham groups. Afterhyperpolarization AHP time to peak of spontaneous action potential (AP) was prolonged after castration.These findings suggest that castration decreases song stereotypy and excitability of RA PNs in male zebra finches. PMID:24765586

Wang, Songhua; Liao, Congshu; Li, Fengling; Liu, Shaoyi; Meng, Wei; Li, Dongfeng

2014-01-01

199

Zebra Finch Mates Use Their Forebrain Song System in Unlearned Call Communication  

Science.gov (United States)

Unlearned calls are produced by all birds whereas learned songs are only found in three avian taxa, most notably in songbirds. The neural basis for song learning and production is formed by interconnected song nuclei: the song control system. In addition to song, zebra finches produce large numbers of soft, unlearned calls, among which “stack” calls are uttered frequently. To determine unequivocally the calls produced by each member of a group, we mounted miniature wireless microphones on each zebra finch. We find that group living paired males and females communicate using bilateral stack calling. To investigate the role of the song control system in call-based male female communication, we recorded the electrical activity in a premotor nucleus of the song control system in freely behaving male birds. The unique combination of acoustic monitoring together with wireless brain recording of individual zebra finches in groups shows that the neuronal activity of the song system correlates with the production of unlearned stack calls. The results suggest that the song system evolved from a brain circuit controlling simple unlearned calls to a system capable of producing acoustically rich, learned vocalizations. PMID:25313846

Ter Maat, Andries; Trost, Lisa; Sagunsky, Hannes; Seltmann, Susanne; Gahr, Manfred

2014-01-01

200

Castration modulates singing patterns and electrophysiological properties of RA projection neurons in adult male zebra finches  

Directory of Open Access Journals (Sweden)

Full Text Available Castration can change levels of plasma testosterone. Androgens such as testosterone play an important role in stabilizing birdsong. The robust nucleus of the arcopallium (RA is an important premotor nucleus critical for singing. In this study, we investigated the effect of castration on singing patterns and electrophysiological properties of projection neurons (PNs in the RA of adult male zebra finches. Adult male zebra finches were castrated and the changes in bird song assessed. We also recorded the electrophysiological changes from RA PNs using patch clamp recording. We found that the plasma levels of testosterone were significantly decreased, song syllable’s entropy was increased and the similarity of motif was decreased after castration. Spontaneous and evoked firing rates, membrane time constants, and membrane capacitance of RA PNs in the castration group were lower than those of the control and the sham groups. Afterhyperpolarization AHP time to peak of spontaneous action potential (AP was prolonged after castration.These findings suggest that castration decreases song stereotypy and excitability of RA PNs in male zebra finches.

Songhua Wang

2014-04-01

201

Phosphorylation of Epstein-Barr Virus ZEBRA Protein at Its Casein Kinase 2 Sites Mediates Its Ability To Repress Activation of a Viral Lytic Cycle Late Gene by Rta  

OpenAIRE

ZEBRA, a member of the bZIP family, serves as a master switch between latent and lytic cycle Epstein-Barr virus (EBV) gene expression. ZEBRA influences the activity of another viral transactivator, Rta, in a gene-specific manner. Some early lytic cycle genes, such as BMRF1, are activated in synergy by ZEBRA and Rta. However, ZEBRA suppresses Rta's ability to activate a late gene, BLRF2. Here we show that this repressive activity is dependent on the phosphorylation state of ZEBRA. We find that...

El-guindy, Ayman S.; Miller, George

2004-01-01

202

Acute and chronic effects of an aromatase inhibitor on pair-maintenance behavior of water-restricted zebra finch pairs.  

Science.gov (United States)

Zebra finches are highly social songbirds that maintain life-long monogamous pair-bonds. They rely heavily upon these pair-bonds to survive their ever-changing and unpredictable habitat in the Australian desert. These pair-bonds are maintained via a large repertoire of affiliative behaviors that for most of an individual's life are predominately associated with pair maintenance. Water restriction reduces circulating testosterone levels in male zebra finches and the size of the ovary and oviduct in female zebra finches, but water restriction has little or no effects on pair-maintenance behaviors and local levels of testosterone and estradiol in behaviorally-relevant brain regions. These data suggest that in water-restricted zebra finches, local synthesis of testosterone and estradiol in the brain may support the expression of pair-maintenance behaviors. Here, we directly test whether pair-maintenance behaviors are regulated by estradiol, acting via non-genomic or genomic mechanisms, in water-restricted (i.e., non-breeding) zebra finches. In two experiments, subjects were treated with an aromatase inhibitor (fadrozole) either acutely or chronically, and a variety of pair-maintenance behaviors were quantified. Additionally, we quantified the effect of acute fadrozole treatment on brain and circulating estradiol and testosterone levels. Acute fadrozole administration rapidly decreased estradiol levels in the circulation and brain of males and also rapidly increased testosterone levels in the circulation and brain of both males and females. However, neither the acute nor chronic fadrozole treatment decreased pair-maintenance behaviors. In one case, acute fadrozole treatment promoted affiliation. These data suggest that pair-maintenance behavior in non-breeding zebra finches is not promoted by estradiol acting via either non-genomic or genomic mechanisms. PMID:24231681

Prior, Nora H; Yap, Kang Nian; Soma, Kiran K

2014-01-15

203

Larvae of Chironomids (Insecta, Diptera) Encountered in the Mantle Cavity of Zebra Mussels, Dreissena polymorpha (Bivalvia, Dreissenidae)  

Science.gov (United States)

The paper includes data on species composition of chironomid larvae which were encountered in the mantle cavity of zebra mussels (Dreissena polymorpha) within 7 waterbodies in the Republic of Belarus. All were found to be free-living species commonly present in periphyton and/or benthos. A long-term study of the seasonal dynamics of these larvae in Dreissena did not reveal any typical pattern. Our data suppose that chironomids do not have an obligate association with zebra mussels and possibly enter their mantle cavity inadvertently.

Mastitsky, Sergey E.; Samoilenko, Vera M.

2005-02-01

204

Origin of Spanish invasion by the zebra mussel, Dreissena polymorpha (Pallas, 1771) revealed by amplified fragment length polymorphism (AFLP) fingerprinting  

OpenAIRE

The zebra mussel, Dreissena polymorpha is an aquatic nuisance invasive species originally native to the Ponto-Caspian region where it is found in lakes and delta areas of large rivers draining into the Black and Caspian seas. The dispersal of D. polymorpha began at the end of the 18th century, at a time when shipping trade become increasingly important and many canals were built for linking different navigable river systems in Europe. Over the past 200 years, zebra mussels spread to most of t...

Rajagopal, S.; Pollux, B. J. A.; Peters, J. L.; Cremers, G.; Moon- Staay, S. Y.; Alen, T.; Eygensteyn, J.; Hoek, A. H. A. M.; Palau, A.; Vaate, A. B.; Velde, G.

2009-01-01

205

Expression of fragile X mental retardation protein within the vocal control system of developing and adult male zebra finches  

OpenAIRE

Individuals with fragile X syndrome (FXS) are cognitively impaired and have marked speech delays and deficits. Our goal was to characterize expression of FMRP, the fragile X mental retardation protein, encoded by the gene FMR1, in an animal model that learns to vocalize, namely the zebra finch Taeniopygia guttata (Tgu). We cloned and sequenced the zebra finch ortholog of FMR1 (TguFmr1) and developed an antibody that recognizes TguFmrp specifically. TguFmrp has structural features similar to i...

Winograd, Claudia; Clayton, David; Ceman, Stephanie

2008-01-01

206

Buckling-induced zebra stripe patterns in nematic F-actin  

Science.gov (United States)

Rather than forming a simple and uniform nematic liquid crystal, concentrated solutions of semiflexible polymers, such as F-actin, have been observed to display a spatially periodic switching of the nematic director. When observed with polarization microscopy, these patterns appear as alternating light and dark bands, often referred to as zebra stripe patterns. Zebra stripe patterns, although not fully characterized, are due to periodic orientation distortions in the nematic order. We characterize such patterns by using a combination of two techniques. Using polarization microscopy, we quantify the periodic orientation distortions and show that the magnitude of the order parameter also varies periodically in the striped domains. When using fluorescently labeled filaments as markers, filaments spanning the striped domains are seen to undergo large angle bends. With fluorescence, clear density differences between adjacent stripes are also observed with domains of lesser density corresponding to strongly bent filaments. By directly comparing patterned areas with both polarization and fluorescence techniques, we show that periodic variation in the orientation, order parameter, filament bending, and density are correlated. We propose that these effects originate from the coupling of orientation and density that occurs for highly concentrated solutions of long semiflexible polymers subject to shear flows, as previously proposed [P. de Gennes, Mol. Cryst. Liq. Cryst. (Phila. Pa.) 34, 177 (1977)]. After cessation of shearing, strong interfilament interactions and high compressibility can lead to periodic buckling from the relaxation of filaments stretched during flows. The characterization of zebra stripe patterns presented here provides evidence that buckling in confined F-actin nematics produces strong periodic bending that is responsible for the observed features.

Gentry, Brian; Smith, David; Käs, Josef

2009-03-01

207

Comparative analysis of theories of zebra-pattern in solar radio emission  

Science.gov (United States)

Strong and weak aspects of different theories of fine structure on solar radio emission dynamic spectra observed as several or numerous quasi- equidistant bands of enhanced and reduced radiation (zebra-pattern) are discussed. Most of works proposing zebra-pattern interpretation is based on plasma mechanism of radio emission generation which consists of exciting plasma (electrostatic) waves and their succeeding transformation into electromagnetic emission. Plasma waves arise due to kinetic or hydrodynamic instability at the upper hybrid frequencies (at the levels of double plasma resonance in a distributed source) or at the electron gyrofrequency harmonics (Bernstein modes in a compact source with quasi-uniform magnetic field). The reason for the instability is occurrence of a number of electrons with nonequilibrium distribution over velocities perpendicular to magnetic field. Radio emission escaping from the source is a result of nonlinear coalescence of plasma waves with low frequency or high frequency waves which does not break the harmonic character of spectrum. A significant number of works is devoted to considering whistlers as a main reason for occurring stripes in emission and absorption on dynamic spectra. Whistlers are also believed to be excited by a group of nonequilibrium electrons, and then some nonlinear processes including whistler interaction result in specific frequency spectrum with enhanced and reduced radiation stripes. An alternative theory of zebra-pattern origin suggests the presence of a compact source with trapped plasma waves in the corona. The trapped waves in a confined space easily provide discrete spectrum. One more interpretation is based on special effects that may occur when radio waves are propagating through non-uniform coronal plasma: the alternate bright and dark stripes on dynamic spectra are supposed to be a result of radio wave interference or diffraction on some periodical structure in the solar corona. All suggested mechanisms are analyzed with relation to their capability to give the best fit for the observed fine structure features in the framework of the source model with reasonable physical parameters.

Zlotnik, E.

2007-08-01

208

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.

209

IMPACT OF THE DURATION OF BACTERIAL EXPOSURE ON ZEBRA MUSSEL MORTALITY  

International Nuclear Information System (INIS)

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

210

Phase specific morphological changes induced by social experience in two forebrain areas of the zebra finch  

OpenAIRE

We examined the changes of spine density in Golgi preparations of two different areas of the forebrain of the zebra finch, the ANC (Archi-Neostriatum caudale) and MNH (medial Neo-Hyperstriatum) during development, after transferring male birds from isolation to a social condition (exposure to a female for 1 week), and after a second isolation period. MNH and ANC are two of four brain regions which are strongly activated if a male bird is exposed to a female after some time of isolation. The r...

Rollenhagen, Astrid; Bischof, Hans-joachim

1994-01-01

211

Microwave Zebra Pattern Structures in the X2.2 Solar Flare on Feb 15, 2011  

OpenAIRE

Zebra pattern structure (ZP) is the most intriguing fine structure on the dynamic spectrograph of solar microwave burst. On 15 February 2011, there erupts an X2.2 flare event on the solar disk, it is the first X-class flare since the solar Schwabe cycle 24. It is interesting that there are several microwave ZPs observed by the Chinese Solar Broadband Radiospectrometer (SBRS/Huairou) at frequency of 6.40 ~ 7.00 GHz (ZP1), 2.60 ~ 2.75 GHz (ZP2), and the Yunnan Solar Broadband ...

Tan, Baolin; Yan, Yihua; Tan, Chengming; Sych, Robert; Gao, Guannan

2011-01-01

212

Nestling diet, secondary sexual traits and fitness in the zebra finch  

OpenAIRE

We examined the effect of nestling diet quality on a suite of physiological, morphological and life-history traits in adult male zebra finches,Taeniopygia guttata. Compared with birds reared on a supplemented diet, nestlings reared on a seed-only diet showed a reduced rate of growth and reduced cell-mediated immune function as measured by an in vivo response to aT lymphocyte-dependent mitogen. There were no differences between birds reared on the two diets in any of the following adult ...

Birkhead, T. R.; Fletcher, F.; Pellatt, E. J.

1999-01-01

213

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

International Nuclear Information System (INIS)

This report addresses environmental, health, and safety (EH ampersand 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 com- pels 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

214

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

215

Todralazine protects zebra fish from lethal doses of ionizing radiation: role of hematopoietic stem cell expansion  

International Nuclear Information System (INIS)

Radiation induced cell killing and hematopoietic stem cell depletion leads to compromised immune functions and opportunistic infections which significantly affect the recovery and survival upon irradiation. Any agent which can expand residual hematopoietic stem cells in irradiated organism can render protection from the effects of lethal doses of ionizing radiation. Johns Hopkins Clinical compound library (JHCCL) was screened for protection against lethal doses of ionizing radiation using developing zebra fish as a model organism. Modulation of radiation induced reactive oxygen species by the small molecules were done by DCFDA staining and for visual identification and quantification of apoptosis acridine orange assay, flow cytometry were employed respectively. Hematopoietic stem cell expansion potential was assessed by quantifying runx1 expression, a marker for definitive stem cells, were done by RT-PCR and by the kinetics of recovery from chemically induced anaemia. Todralazine hydrochloride from JHCCL exhibited promising results with potential anti radiation effects. A dose of 5?M was found to be the most effective and has rendered significant organ and whole body protection (100% survival advantage over a period of 6 days) against 20 Gy. However todralazine did not modulated radiation induced free radicals (monitored within 2 h of irradiation) and apoptosis in zebra fish embryos analysed at 8 and 24h post irradiation. Flow cytometric quantification of pre G1 population suggested the same. Chemoinformatics approaches were further carried out to elucidate possible targets which are contributing to its radioprotection potential. Structural similarity search suggested several targets and possible hematopoietic stem cell expanding potential. Treatment of zebra fish embryos with todralazine has lead to significant proliferation of hematopoietic stem cell as indicated by increase in expression of runx1. HSC expanding potential of todralazine was further supported by its ability to increase the formation of erythrocytes in phenyl hydrazine induced anaemic zebra fish embryos. Todralazine is a HSC expanding agent with radioprotective potential and HSC expanding potential seems to be primarily responsible for that. Methodologies, results and its translational potential will be discussed in detail during presentation. (author)

216

Producción secundaria e índice de condición en Arca zebra (Mollusca: Bivalvia) del Golfo de Cariaco, Venezuela  

OpenAIRE

Se estudió la biomasa, producción secundaria e índice de condición del bivalvo Arca zebra, desde agosto, 1984 hasta agosto, 1985 en Pariche, localidad situada en la costa norte del Golfo de Cariaco, Venezuela. La densidad promedio fue de 37 ind.m-2, con una mayor abundancia a 3 m de profundidad (49.75 ind.m-2). La estructura poblacional es estable con reclutamientos en octubre, diciembre 1984 y junio 19885. Los valores bimensuales de biomasa oscilaron entre 189.86 g Ps m-2 (agosto-84) y 2...

Antulio Prieto Arcas; Omar Ramos A.; Dwight Arrieche; José Villalba; César Lodeiros

2001-01-01

217

Acute inhibition of a cortical motor area impairs vocal control in singing zebra finches.  

Science.gov (United States)

Genetically targeted approaches that permit acute and reversible manipulation of neuronal circuit activity have enabled an unprecedented understanding of how discrete neuronal circuits control animal behavior. Zebra finch singing behavior has emerged as an excellent model for studying neuronal circuit mechanisms underlying the generation and learning of behavioral motor sequences. We employed a newly developed, reversible, neuronal silencing system in zebra finches to test the hypothesis that ensembles of neurons in the robust nucleus of the arcopallium (RA) control the acoustic structure of specific song parts, but not the timing nor the order of song elements. Subunits of an ivermectin-gated chloride channel were expressed in a subset of RA neurons, and ligand administration consistently suppressed neuronal excitability. Suppression of activity in a group of RA neurons caused the birds to sing songs with degraded elements, although the order of song elements was unaffected. Furthermore some syllables disappeared in the middle or at the end of song motifs. Thus, our data suggest that generation of specific song parts is controlled by a subset of RA neurons, whereas elements order coordination and timing of whole songs are controlled by a higher premotor area. PMID:25354166

Yazaki-Sugiyama, Yoko; Yanagihara, Shin; Fuller, Patrick M; Lazarus, Michael

2015-01-01

218

Cave crawling in zebra finch skulls : what is the functional interaural canal?  

DEFF Research Database (Denmark)

Cave crawling in zebra finch skulls: what is the functional interaural canal? Ole Næsbye Larsen, Rasmus Salomon, Kenneth Kragh Jensen, and Jakob Christensen-Dalsgaard Department of Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark The middle ears of birds are acoustically coupled through an air-filled interaural canal (IAC) often illustrated and modelled as a simple tube, which allows sound to propagate through the skull from one ear to the other and considerably enhance the cues for directional hearing. Theoretically, different combinations of frequency dependent gains and delays in the IAC can produce very different directionalities of the ears but it is still uncertain how interaural transmission gain and delay can be shaped by evolution by anatomical adaptations. A closer inspection of the zebra finch cranium using micro-CT scanning reveals that not only is IAC trabeculated and irregularly shaped but it also communicates with a set of highly complex, air-filled canals in the skull extending to the base of the beak. We tested the possible influence of these communicating cavities by measuring eardrum directionality and interaural transmission before and after filling the frontal cavities but found no dramatic effects. The question still remains what function these cavities serve and whether the ICA should be modelled as a simple tube.

Larsen, Ole Næsbye; Salomon, Rasmus

219

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

220

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

221

In vivo recording of single-unit activity during singing in zebra finches.  

Science.gov (United States)

The zebra finch is an important model for investigating the neural mechanisms that underlie vocal production and learning. Previous anatomical and gene expression studies have identified an interconnected set of brain areas in this organism that are important for singing. To advance our understanding of how these various brain areas act together to learn and produce a highly stereotyped song, it is necessary to record the activity of individual neurons during singing. Here, we present a protocol for recording single-unit activity in freely moving zebra finches during singing using a miniature, motorized microdrive. It includes procedures for both the microdrive implant surgery and the electrophysiological recordings. There are several advantages of this technique: (1) high-impedance electrodes can be used in the microdrive to obtain well-isolated single units; (2) a motorized microdrive is used to remotely control the electrode position, allowing neurons to be isolated without handling the bird, and (3) a lateral positioner is used to move electrodes into fresh tissue before each penetration, allowing recordings from well-isolated neurons over the course of several weeks. We also describe the application of the antidromic stimulation and the spike collision test to identify neurons based on the axonal projection patterns. PMID:25342072

Okubo, Tatsuo S; Mackevicius, Emily L; Fee, Michale S

2014-12-01

222

Zebra finches can use positional and transitional cues to distinguish vocal element strings.  

Science.gov (United States)

Learning sequences is of great importance to humans and non-human animals. Many motor and mental actions, such as singing in birds and speech processing in humans, rely on sequential learning. At least two mechanisms are considered to be involved in such learning. The chaining theory proposes that learning of sequences relies on memorizing the transitions between adjacent items, while the positional theory suggests that learners encode the items according to their ordinal position in the sequence. Positional learning is assumed to dominate sequential learning. However, human infants exposed to a string of speech sounds can learn transitional (chaining) cues. So far, it is not clear whether birds, an increasingly important model for examining vocal processing, can do this. In this study we use a Go-Nogo design to examine whether zebra finches can use transitional cues to distinguish artificially constructed strings of song elements. Zebra finches were trained with sequences differing in transitional and positional information and next tested with novel strings sharing positional and transitional similarities with the training strings. The results show that they can attend to both transitional and positional cues and that their sequential coding strategies can be biased toward transitional cues depending on the learning context. This article is part of a Special Issue entitled: In Honor of Jerry Hogan. PMID:25217867

Chen, Jiani; Ten Cate, Carel

2014-09-11

223

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

Energy Technology Data Exchange (ETDEWEB)

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.

Watson, J.T.; Adkins-Regan, E.; Whiting, P.; Lindstrom, J.M.; Podleski, T.R.

1988-08-08

224

Discrimination of dynamic moving ripples in the zebra finch, Taeniopygia guttata  

Science.gov (United States)

Auditory processing of complex broadband sounds known as moving ripples has been studied both physiologically at the cortical level in mammals and psychophysically in humans [Depireux et al. (2001); Chi et al. (1999)]. These stimuli share spectro-temporal properties with many natural sounds, including species-specific vocalizations and the formant transitions of human speech [Versnel and Shamma (1998)]. One test of the generality of ripple processing beyond mammals would be to examine a non-mammalian species. Zebra finches may be excellent subjects for such a study because they produce complex broadband harmonic songs and neuronal responses in their auditory forebrain may be exquisitely tuned to the specific spectro-temporal patterns of their songs [Theunnissen and Doupe (1998)]. We trained these birds to discriminate between flat-spectrum broadband noise and moving ripples of different densities that move up or down in frequency at various rates. Results show that discrimination in zebra finches is better at those ripple densities and velocities which are prominent in their species-specific harmonic vocalizations. [Work supported by NIH Grant No. DC-00198 to RJD and NIDCD Training Grant No. DC-00046.

Osmanski, Michael S.; Dooling, Robert J.; Depireux, Didier A.

2002-05-01

225

Lifelong consequences of early nutritional conditions on learning performance in zebra finches (Taeniopygia guttata).  

Science.gov (United States)

Long-term effects of early developmental conditions on physiological and behavioural traits are common in animals. Yet, such lifelong effects of early life conditions on learning skills received relatively less attention, even though they are expected to have strong fitness effects. To test the lifelong impact of the early environment on associative and reversal learning performance, we tested zebra finches (Taeniopygia guttata) in a reversal learning task about five years after they were raised either under low or high quality food treatments in their first month of life. The early nutritional treatment and its respective growth patterns significantly influenced learning performance: Zebra finches who received a high-quality nutrition early in life gained more weight during the treatment period but needed more trials to associate a cue with a reward. The early growth rate during the treatment phase was linked to how fast the birds detected the food at the onset of training in our learning task as well as to their associative learning performance. However, in the reversal learning step of the task testing for behavioural flexibility, no differences with respect to early nutritional treatments or related growth rates were apparent. We show that early life conditions directly affect the approach to our task and learning abilities over an entire lifetime, emphasizing how crucial the early environment is for understanding adult behaviour throughout life. PMID:24480407

Brust, Vera; Krüger, Oliver; Naguib, Marc; Krause, E Tobias

2014-03-01

226

Chronological history of zebra and quagga mussels (Dreissenidae) in North America, 1988-2010  

Science.gov (United States)

An unprecedented invasion began in North America in the mid-/late-1980s when two Eurasian mussel species, Dreissena polymorpha (zebra mussel) and Dreissena rostriformis bugensis (quagga mussel), became established in Laurentian Great Lakes. It is believed that Lake Erie was the initial location of establishment for both species, and within 3 years, zebra mussels had been found in all the Great Lakes. Since 1986, the combined distribution of two dreissenids has expanded throughout the Great Lakes region and the St. Lawrence River in Canada and also in the United States from the Great Lakes to the Mississippi Basin including Arkansas, Cumberland, Illinois, Missouri, Ohio, and Tennessee river basins. The distribution of dreissenid mussels in the Atlantic drainage has been limited to the Hudson and Susquehanna rivers. In the western United States, the quagga mussel established a large population in the lower Colorado River and spread to reservoirs in Arizona, California, Colorado, Nevada, and Utah. Overall, dreissenid species have been documented in 131 river systems and 772 inland lakes, reservoirs, and impoundments in the United States.

Benson, Amy J.

2013-01-01

227

Female but not male zebra finches adjust heat output in response to increased incubation demand.  

Science.gov (United States)

In many incubating birds, heat transfer from parent to egg is facilitated by the brood patch, an area of ventral abdominal skin that becomes highly vascularised, swells and loses its down feathers around the time of laying. Only the female develops a brood patch in most passerine species, but males of some species can incubate and maintain the eggs at similar temperatures to females even without a brood patch. Here we used a novel application of infrared thermography to examine sex differences in parental care from a physiological perspective. Using incubating male and female zebra finches (Taeniopygia guttata), a species in which the male lacks a brood patch, we measured the surface temperature of the ventral plumage overlying the abdomen and a reference area that does not contact the eggs (thorax) twice per pair. In half of the pairs, clutch size was experimentally enlarged between the two sets of measurements to increase incubation demand. We found that the temperature differential between abdomen and thorax plumage was greater in females than in males, and that abdomen plumage was warmer after clutch enlargement than before in females but not in males. These findings are consistent with morphological sex differences in brood patch development and suggest that male and female zebra finches differ in the way they regulate abdomen versus general body surface temperature in response to variation in incubation demand. PMID:24363422

Hill, Davina L; Lindström, Jan; McCafferty, Dominic J; Nager, Ruedi G

2014-04-15

228

Assessment of Mercury Bioaccumulation in Zebra Cichlid (Cichlasoma Nigrofasciatum Exposed to Sublethal Concentrations of Permethrin  

Directory of Open Access Journals (Sweden)

Full Text Available Background: Aquatic ecosystems are frequently subjected to contamination by toxic heavy metals and pesticides, yet very little is known about the influence of pesticides on bioaccumulation of heavy metals in aquatic organisms. Mercury is a toxic metal with no known biological benefit to organisms. Bioavailability of mercury in aquatic environments depends on biological and non-biological parameters including other pollutants. Therefore, the objectives of this research were to determine the effects of permethrin on bioaccumulation of mercury in zebra cichlid. Methods: Acute toxicity (LC50 of permethrin and mercury chloride was evaluated by estimating mortality in Probit Model in SPSS (version 19.0 IBM. In sub-lethal toxicity, zebra cichlid (Cichlasoma nigrofasciatum was exposed to various concentrations of permethrin (0.0, 0.40, 0.80, 1.20 and 1.60 µg.L-1 combined with 20 µg.L-1 mercury chloride for 15 days. At the end of the experiment, mercury concentrations were measured using ICP-OES-Perkin elmer (optima 7300-DV. Results: 96 h LC50 values of permethrin and mercury for C. nigrofasciatum were calculated to be 17.55 µg.L-1 and 140.38 µg.L-1, respectively. Our results clearly showed that the bioaccumulation of mercury in the specimens increased with increasing concentrations of permethrin to 1.20 and 1.60 µg.L-1. Conclusion: Increasing the concentration of permethrin had synergistic effects on the bioaccumulation of mercury in fish.

Mahdi Banaee

2014-12-01

229

Association of Bactericera cockerelli (Homoptera: Psyllidae) with 'Zebra Chip', a New Potato Disease in Southwestern United States and Mexico  

Science.gov (United States)

A new defect of potato (Solanum tuberosum L.), “Zebra Chip”, so-named for the characteristic symptoms that develop in fried chips processed from affected potato tubers has recently been documented in several southwestern states of the United States, Mexico, and Central America. This defect is causin...

230

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 ...

231

Formation of zebra patterns of solar microwave bursts as a result of propagation of radio waves through the inhomogeneous corona  

Science.gov (United States)

The geoefficiency of solar bursts is diagnosed using the dynamic radio emission spectrum. At certain time intervals, the spectrum exhibits nearly parallel narrow-band emission strips termed the zebra pattern. Although there are many hypotheses of its origin, all of them do not take into account changes in the signal parameters upon signal propagation through the solar corona. Our analysis shows that the propagation effects form a dynamic spectrum that contains a zebra pattern. The properties of the modeled spectrum are shown to coincide with the basic properties of the observed spectrum. It is clarified that the spike structure of strips is a natural consequence of the interference of radio waves, and the occurrence of this structure is considered to be evidence in favor of the interference nature of the zebra pattern formation. Consequently, the zebra pattern can be formed not in the radiation source itself, but rather can arise as a result of propagation of radio waves through an inhomogeneous refracting medium of the solar corona.

Yurovsky, Yu. F.

2008-06-01

232

An eye for beauty: lateralized visual stimulation of courtship behavior and mate preferences in male zebra finches, Taeniopygia guttata.  

Science.gov (United States)

Research on intersexual selection focuses on traits that have evolved for attracting mates and the consequences of mate choice. However, little is known about the cognitive and neural mechanisms that allow choosers to discriminate among potential mates and express an attraction to specific traits. Preferential use of the right eye during lateral displays in zebra finches, and lateralized expression of intermediate early genes in the left hemisphere during courtship led us to hypothesize that: (1) visual information from each eye differentially mediates courtship responses to potential mates; and (2) the ability to discriminate among mates and prefer certain mates over others is lateralized in the right eye/left hemisphere system of zebra finch brains. First, we exposed male zebra finches to females when using left, right or both eyes. Males courted more when the right eye was available than when only the left eye was used. Secondly, male preference for females - using beak color to indicate female quality - was tested. Right-eyed and binocular males associated with and courted orange-beaked more than gray-beaked females; whereas left-eyed males showed no preference. Lateral displays and eye use in male zebra finches increase their attractiveness and ability to assess female quality, potentially enhancing reproductive success. This article is part of a Special Issue entitled: CO3 2013. PMID:24239504

Templeton, Jennifer J; McCracken, Brianna G; Sher, Melissa; Mountjoy, D James

2014-02-01

233

Zebra tape identification for the instantaneous angular speed computation and angular resampling of motorbike valve train measurements  

Science.gov (United States)

An experimental test campaign was performed on the valve train of a racing motorbike engine in order to get insight into the dynamic of the system. In particular the valve motion was acquired in cold test conditions by means of a laser vibrometer able to acquire displacement and velocity signals. The valve time-dependent measurements needed to be referred to the camshaft angular position in order to analyse the data in the angular domain, as usually done for rotating machines. To this purpose the camshaft was fitted with a zebra tape whose dark and light stripes were tracked by means of an optical probe. Unfortunately, both manufacturing and mounting imperfections of the employed zebra tape, resulting in stripes with slightly different widths, precluded the possibility to directly obtain the correct relationship between camshaft angular position and time. In order to overcome this problem, the identification of the zebra tape was performed by means of the original and practical procedure that is the focus of the present paper. The method consists of three main steps: namely, an ad-hoc test corresponding to special operating conditions, the computation of the instantaneous angular speed, and the final association of the stripes with the corresponding shaft angular position. The results reported in the paper demonstrate the suitability of the simple procedure for the zebra tape identification performed with the final purpose to implement a computed order tracking technique for the data analysis.

Rivola, Alessandro; Troncossi, Marco

2014-02-01

234

Organotins in zebra mussels (Dreissena polymorpha) and sediments of the Quebec City Harbour area of the St. Lawrence River.  

Science.gov (United States)

Toxic antifouling agents such as tributyltin (TBT) and triphenyltin (TPT) have been released in aquatic ecosystems through the use of antifouling paint applied to ship hulls, pleasure crafts and fish nets and these compounds can bioaccumulate in aquatic organisms. The purpose of this study was 1) to assess the extent of the distribution of organotins from a contaminated marina to the St. Lawrence River system by measuring organotin concentrations in zebra mussels (Dreissena polymorpha) and in sediments collected from 9 sites along the St. Lawrence River near Quebec City in July 1998, and 2) to examine the histopathological condition of zebra mussel tissues from these sites. TBT concentrations in zebra mussels were between 37 and 1078 ng Sn g(-1) wet weight, with the highest value found in the Bassin Louise marina. Elevated concentrations were also found in two other marinas. The concentrations decreased sharply to background levels just outside the marinas. All butyltins were detected in all sediments analysed, with highest values found in the Bassin Louise marina. Phenyltins were detected in three of the nine sites in low concentrations (TBT in sediments and mussels. Gonadal development of zebra mussels varied largely between sites, and was negatively associated to TBT levels in mussel tissue. This study shows that TBT contamination remains a problem in localised freshwater sectors of the St. Lawrence River. PMID:11311388

Regoli, L; Chan, H M; de Lafontaine, Y; Mikaelian, I

2001-07-01

235

First report of zebra chip disease and Candidatus Liberibacter solanacearum on potatoes in Oregon and Washington State  

Science.gov (United States)

In August of 2011, potato (Solanum tuberosum) tubers grown in the lower Columbia Basin of southern Washington State and northern Oregon were observed with internal discolorations suggestive of the zebra chip disease (ZC). Symptoms included brown spots, streaks, and stripes in and near the vascular ...

236

Song exposure regulates known and novel microRNAs in the zebra finch auditory forebrain  

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Full Text Available Abstract 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.

Kim Jong H

2011-05-01

237

Sexually dimorphic expression of the genes encoding ribosomal proteins L17 and L37 in the song control nuclei of juvenile zebra finches  

OpenAIRE

Studies evaluating the role of steroid hormones in sexual differentiation of the zebra finch song system have produced complicated and at times paradoxical results, and indicate that additional factors may be critical. Therefore, in a previous study we initiated a screen for differential gene expression in the telencephalon of developing male and female zebra finches. The use of cDNA microarrays and real-time quantitative PCR revealed increased expression of the genes encoding ribosomal prote...

Tang, Yu Ping; Wade, Juli

2006-01-01

238

Mutations of Amino Acids in the DNA Recognition Domain of Epstein-Barr Virus ZEBRA Protein Alter Its Sub-nuclear Localization and Affect Formation of Replication Compartments  

OpenAIRE

ZEBRA, a transcription factor and DNA replication protein encoded by the Epstein Barr virus (EBV) BZLF1 gene, plays indispensible roles in the EBV lytic cycle. We recently described the phenotypes of 46 single amino acid substitutions introduced into the DNA recognition region of ZEBRA (Heston et al., 2006). The 27 DNA binding-proficient mutants exhibited distinct defects in their ability to activate expression of the kinetic classes of viral genes. Four phenotypic variants could be discerned...

Park, Richard; Heston, Lee; Shedd, Duane; Delecluse, Henri-jacques; Miller, George

2008-01-01

239

Small molecule analysis and imaging of fatty acids in the zebra finch song system using time-of-flight-secondary ion mass spectrometry  

OpenAIRE

Fatty acids are central to brain metabolism and signaling, but their distributions within complex brain circuits have been difficult to study. Here we applied an emerging technique, time-of-flight secondary ion mass spectrometry (ToF-SIMS), to image specific fatty acids in a favorable model system for chemical analyses of brain circuits, the zebra finch (Taeniopygia guttata). The zebra finch, a songbird, produces complex learned vocalizations under the control of an interconnected set of disc...

Amaya, Kensey R.; Sweedler, Jonathan V.; Clayton, David F.

2011-01-01

240

Quasi-periodic Wiggles of Microwave Zebra Structures in a Solar Flare  

Science.gov (United States)

Quasi-periodic wiggles of microwave zebra pattern (ZP) structures with periods ranging from about 0.5 s to 1.5 s are found in an 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 to three significant periodicities and are almost in phase between stripes at different frequencies. The Alfvén speed estimated from the ZP structures is about 700 km s-1. We find the spatial size of the wave-guiding plasma structure to be about 1 Mm with a detected period of about 1 s. This suggests that the ZP wiggles can be associated with the fast magnetoacoustic 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; Nakariakov, V. M.; Selzer, L. A.; Tan, Baolin; Yan, Yihua

2013-11-01

241

Relationship between physical and genetic distances along the zebra finch Z chromosome.  

Science.gov (United States)

Nine bacterial artificial chromosomes containing genes linked to the Z chromosome of the zebra finch (Taeniopygia guttata) were localized using FISH on synaptonemal complex spreads. Their positions were correlated with those previously reported on the mitotic Z chromosome, showing a linear relationship between positions along the mitotic chromosome and its synaptonemal complex. Distances in cM between the genes were calculated using a cytological map of the crossing-over based on the distribution of MLH1 foci along the ZZ synaptonemal complex (MLH1-cM map). It is shown that physical and genetic distances lack a linear relationship along most of the chromosome length, due to clustering of crossover events around the telomeres. This relationship departs strongly from that observed in the chicken Z chromosome and reflects the existence of different recombination rates and patterns among birds in spite of wide genomic conservation. PMID:18668333

Pigozzi, María Inés

2008-01-01

242

Chronic dietary toxicity of methylmercury in the zebra finch, Poephila guttata  

Energy Technology Data Exchange (ETDEWEB)

Mercury (Hg) contamination of the environment through anthropogenic activity continues to be significant, and has resulted in the accumulation of elevated levels of Hg in invertebrates, fish and wildlife in certain Hg contaminated habitats. In addition, the availability of methylmercury (MeHg), a highly toxic and readily absorbable form of Hg, to the food chain is enhanced at low pH, an this has resulted in higher concentrations of Hg in various biota which inhabit environments sensitive to acid precipitation. The chronic dietary toxicity of MeHg has been investigated in a number of bird species including mallard ducks (Anas platyrhynchos, black ducks, pheasants, quail, and chickens. Except for a subchronic feeding study, the effects of MeHg on small passerines have not been studied. The present report describes the tissue accumulation and toxicity of MeHg in zebra finches (Poephila guttata) in response to chronic dietary exposure.

Scheuhammer, A.M.

1988-01-01

243

A neural circuit mechanism for regulating vocal variability during song learning in zebra finches.  

Science.gov (United States)

Motor skill learning is characterized by improved performance and reduced motor variability. The neural mechanisms that couple skill level and variability, however, are not known. The zebra finch, a songbird, presents a unique opportunity to address this question because production of learned song and induction of vocal variability are instantiated in distinct circuits that converge on a motor cortex analogue controlling vocal output. To probe the interplay between learning and variability, we made intracellular recordings from neurons in this area, characterizing how their inputs from the functionally distinct pathways change throughout song development. We found that inputs that drive stereotyped song-patterns are strengthened and pruned, while inputs that induce variability remain unchanged. A simple network model showed that strengthening and pruning of action-specific connections reduces the sensitivity of motor control circuits to variable input and neural 'noise'. This identifies a simple and general mechanism for learning-related regulation of motor variability. PMID:25497835

Garst-Orozco, Jonathan; Babadi, Baktash; Ölveczky, Bence P

2014-01-01

244

Developmental changes in BDNF protein in the song control nuclei of zebra finches.  

Science.gov (United States)

The zebra finch song system provides an excellent model to study the mechanisms underlying the development of sex difference in brain structure and function. Only male zebra finches sing and the brain nuclei controlling song learning and production are considerably larger than in females. Sexual differentiation may in part be regulated by estrogen, but other molecules including neurotrophic factors likely also affect masculinization. Brain derived neurotrophic factor (BDNF) plays a crucial role in numerous aspects of vertebrate brain development and function, including neurogenesis, cell survival, growth of axonal projections, synaptogenesis and processes linked to learning and memory. The current study investigated the expression of BDNF protein in juvenile males and females at four ages, as well as in adults, to begin to evaluate the potential roles of endogenous BDNF in particular stages of structural and functional development of the song system. In both HVC and the robust nucleus of the arcopallium (RA), males had more BDNF+ cells than females. The number of immunopositive cells increased in males and decreased in females as they matured, in a pattern generally consistent with a role for BDNF in sensorimotor integration of song learning. In addition, in HVC (but not RA) the ratio of mature BDNF compared to its precursor proBDNF was greater in adult males than those at post-hatching day 25, indicating a region-specific shift in the relative availability of the two forms. Collectively, the data suggest that changes in BDNF protein expression across development may be associated with song system maturation, particularly during the sensorimotor integration of masculine vocalizations. PMID:23920158

Tang, Y P; Wade, J

2013-10-10

245

Myosin heavy-chain isoforms in the flight and leg muscles of hummingbirds and zebra finches.  

Science.gov (United States)

Myosin heavy chain (MHC) isoform complement is intimately related to a muscle's contractile properties, yet relatively little is known about avian MHC isoforms or how they may vary with fiber type and/or the contractile properties of a muscle. The rapid shortening of muscles necessary to power flight at the high wingbeat frequencies of ruby-throated hummingbirds and zebra finches (25-60 Hz), along with the varied morphology and use of the hummingbird hindlimb, provides a unique opportunity to understand how contractile and morphological properties of avian muscle may be reflected in MHC expression. Isoforms of the hummingbird and zebra finch flight and hindlimb muscles were electrophoretically separated and compared with those of other avian species representing different contractile properties and fiber types. The flight muscles of the study species operate at drastically different contraction rates and are composed of different histochemically defined fiber types, yet each exhibited the same, single MHC isoform corresponding to the chicken adult fast isoform. Thus, despite quantitative differences in the contractile demands of flight muscles across species, this isoform appears necessary for meeting the performance demands of avian powered flight. Variation in flight muscle contractile performance across species may be due to differences in the structural composition of this conserved isoform and/or variation within other mechanically linked proteins. The leg muscles were more varied in their MHC isoform composition across both muscles and species. The disparity in hindlimb MHC expression between hummingbirds and the other species highlights previously observed differences in fiber type composition and thrust production during take-off. PMID:24671242

Velten, Brandy P; Welch, Kenneth C

2014-06-01

246

Calculations for the intermediate-spectrum cells of Zebra 8 using the MONK Monte-Carlo Code  

International Nuclear Information System (INIS)

The Monte-Carlo Code MONK 6A and its associated point-energy cross-section data have been used to analyse seven, zero-leakage, plate-geometry cells from the ZEBRA 8 assemblies. The convergence of the calculations was such that the uncertainties in k-infinity and the more important reaction-rate ratios were generally less than the experimental uncertainties. The MONK 6A predictions have been compared with experiment and with predictions from the MURAL collision-probability code. This uses FGL5 data which has been adjusted on the basis of ZEBRA 8 and other integral experiments. The poor predictions from the MONK calculations with errors of up to 10% in k-infinity, are attributed to deficiencies in the database for intermediate to fast spectrum systems. (author)

247

Zebra mussels (Dreissena polymorpha) limit food for larval fish (Pimephales promelas) in turbulent systems: A bioenergetics analysis  

Science.gov (United States)

We conducted a factorial experiment, in outdoor mesocosms, on the effects of zebra mussels and water column mixing (i.e., turbulence) on the diet, growth, and survival of larval fathead minnows (Pimephales promelas). Significant (P bioenergetics modeling and measured prey standing stocks indicated caloric resources of suitable prey in turbulence treatments during the early weeks of the experiment were insufficient to prevent starvation. Early mortality in the turbulence and mussels treatment likely released surviving fish from intense intraspecific competition and resulted in higher individual growth rates. A combination of high abundance of zebra mussels in an environment with a well-mixed water column can have significant effects on larval fish survival and growth.

Bartsch, L.A.; Richardson, W.B.; Sandheinrich, M.B.

2003-01-01

248

Identification of larvae: The zebra mussel (Dreissena polymorpha), quagga mussel (Dreissena rosteriformis bugensis), and Asian clam (Corbicula fluminea)  

Science.gov (United States)

There are presently four freshwater bivalves in the United States that produce larvae or veligers commonly found in the water column: two forms of Asian clams and two species of dreissenids. Portions of the geographic range of three of these bivalves, one species of Asian clam (Corbicula fluminea), zebra mussels (Dreissena polymorpha), and quagga mussels (Dreissena rosteriformis bugensis), overlap, causing problems with larval identification. To determine which characteristics can be used to separate larval forms, adult Asian clams, quaggas, and zebra mussels were brought into the laboratory and induced to spawn, and the resulting larvae were reared. Hybrids between quaqqas and zebra mussels were also produced, but not reared to maturity. Characteristics allowing for the most rapid and accurate separation of larvae were hinge length, shell length/height, shell shape, shell size, and the presence or absence of a foot and velum. These characteristics were observed in laboratory-reared larvae of known parentage and field-caught larvae of unknown parentage. In most cases, larvae of the Asian clam can be readily separated from those produced by either type of dreissenid on the basis of shell size and presence of a foot. Separating the gametes and embryos of the two types of dreissenids is not possible, but after shell formation, most of the larval stages can be distinguished. Hinge length, shell length/height, and the similarity in size of the shell valves can be used to separate straight-hinged, umbonal, pediveliger, and plantigrade larvae. Quagga X zebra mussel hybrids show characteriestics of both parents and are difficult to identify.

Nichols, S. Jerrine; Black, M.G.

1994-01-01

249

Song Selectivity in the Pallial-Basal Ganglia Song Circuit of Zebra Finches Raised Without Tutor Song Exposure  

OpenAIRE

Acoustic experience critically influences auditory cortical development as well as emergence of highly selective auditory neurons in the songbird sensorimotor circuit. In adult zebra finches, these “song-selective” neurons respond better to the bird's own song (BOS) than to songs of other conspecifics. Birds learn their songs by memorizing a tutor's song and then matching auditory feedback of their voice to the tutor song memory. Song-selective neurons in the pallial-basal ganglia circuit...

Kojima, Satoshi; Doupe, Allison J.

2007-01-01

250

Sex bias and dosage compensation in the zebra finch versus chicken genomes: General and specialized patterns among birds  

OpenAIRE

We compared global patterns of gene expression between two bird species, the chicken and zebra finch, with regard to sex bias of autosomal versus Z chromosome genes, dosage compensation, and evolution of sex bias. Both species appear to lack a Z chromosome–wide mechanism of dosage compensation, because both have a similar pattern of significantly higher expression of Z genes in males relative to females. Unlike the chicken Z chromosome, which has female-specific expression of the noncoding ...

Itoh, Yuichiro; Replogle, Kirstin; Kim, Yong-hwan; Wade, Juli; Clayton, David F.; Arnold, Arthur P.

2010-01-01

251

Laying-sequence-specific variation in yolk oestrogen levels, and relationship to plasma oestrogen in female zebra finches (Taeniopygia guttata)  

OpenAIRE

We investigated the relationship between plasma and yolk oestrogens in laying female zebra finches (Taeniopygia guttata) by manipulating plasma oestradiol (E2) levels, via injection of oestradiol-17?, in a sequence-specific manner to maintain chronically high plasma levels for later-developing eggs (contrasting with the endogenous pattern of decreasing plasma E2 concentrations during laying). We report systematic variation in yolk oestrogen concentrations, in relation to laying sequence, sim...

Williams, Tony D.; Ames, Caroline E.; Kiparissis, Yiannis; Wynne-edwards, Katherine E.

2005-01-01

252

Subdivisions of the Auditory Midbrain (N. Mesencephalicus Lateralis, pars dorsalis) in Zebra Finches Using Calcium-Binding Protein Immunocytochemistry  

OpenAIRE

The midbrain nucleus mesencephalicus lateralis pars dorsalis (MLd) is thought to be the avian homologue of the central nucleus of the mammalian inferior colliculus. As such, it is a major relay in the ascending auditory pathway of all birds and in songbirds mediates the auditory feedback necessary for the learning and maintenance of song. To clarify the organization of MLd, we applied three calcium binding protein antibodies to tissue sections from the brains of adult male and female zebra fi...

Logerot, Priscilla; Kru?tzfeldt, Nils O. E.; Wild, J. Martin; Kubke, M. Fabiana

2011-01-01

253

Development of neurons in the ectostriatum of normal and monocularly deprived zebra finches: a quantitative Golgi study  

OpenAIRE

The postnatal development of the main neuron type in the ectostriatum, the telencephalic station of the tectofugal pathway, was followed in normally reared and monocularly deprived zebra finches by using the Golgi method. Three parameters were investigated: dendritic field radius, branching index, and spine density. The results show that all three exhibit the same developmental trend - namely, an increase from day 5 until day 20, followed by a subsequent reduction until adulthood (>100 days)....

Herrmann, Kathrin; Bischof, Hans-joachim

1988-01-01

254

Effect of Vocal Nerve Section on Song and ZENK Protein Expression in Area X in Adult Male Zebra Finches  

OpenAIRE

ZENK expression in vocal nuclei is associated with singing behavior. Area X is an important nucleus for learning and stabilizing birdsong. ZENK expression is higher in Area X compared to that in other vocal nuclei when birds are singing. To reveal the relationship between the ZENK expression in Area X and song crystallization, immunohistochemistry was used to detect ZENK protein expression in Area X after the unilateral vocal nerve (tracheosyringeal nerve) section in adult male zebra finches....

Congshu Liao; Dongfeng Li

2012-01-01

255

Sex-specific effects of maternal immunization on yolk antibody transfer and offspring performance in zebra finches  

OpenAIRE

Trans-generational antibody transfer constitutes an important mechanism by which mothers may enhance offspring resistance to pathogens. Thus, differential antibody deposition may potentially allow a female to differentiate offspring performance. Here, we examined whether maternal immunization with sheep red blood cells (SRBC) prior to egg laying affects sex-specific yolk antibody transfer and sex-specific offspring performance in zebra finches (Taeniopygia guttata). We showed that immunized m...

Martyka, Rafa?; Rutkowska, Joanna; Cichon?, Mariusz

2011-01-01

256

Cannabinoid exposure during zebra finch sensorimotor vocal learning persistently alters expression of endocannabinoid signaling elements and acute agonist responsiveness  

OpenAIRE

Abstract Background Previously we have found that cannabinoid treatment of zebra finches during sensorimotor stages of vocal development alters song patterns produced in adulthood. Such persistently altered behavior must be attributable to changes in physiological substrates responsible for song. We are currently working to identify the nature of such physiological changes, and to understand how they contribute to altered vocal learning. One possibility is that developmental ...

Lichtman Aron H; Poklis Justin L; Soderstrom Ken

2011-01-01

257

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

OpenAIRE

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 ma...

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

2012-01-01

258

Research regarding the influence of royal jelly on sex reversal in zebra fishes (Danio rerio)  

OpenAIRE

In this study we observed the influence of royal jelly on sex reversal in zebra fishes (Daniorerio). Experiments were made in the laboratories of aquaculture from Faculty of Animal Science andBiotechnologies, Timi?oara in the period 01.03.2010 – 15.05.2010 on 225 individuals. The dinamics ofstandard body weight, the standard length and the maximum body high at all individuals from treeexperimental variants were evaluated. It was indentified the number of males and females by ...

Silvia P?truic?; Adrian Grozea; Gabi Dumitrescu; Ioan B?n??ean-Dunea; Liliana Ciochin?; Marioara Nicula; Adriana D?ianu; Szidonia Szucs; Liliana Boca

2010-01-01

259

Simple sequence repeats in zebra finch (Taeniopygia guttata) expressed sequence tags: a new resource for evolutionary genetic studies of passerines  

OpenAIRE

Background Passerines (perching birds) are widely studied across many biological disciplines including ecology, population biology, neurobiology, behavioural ecology and evolutionary biology. However, understanding the molecular basis of relevant traits is hampered by the paucity of passerine genomics tools. Efforts to address this problem are underway, and the zebra finch (Taeniopygia guttata) will be the first passerine to have its genome sequenced. Here we describe a bioinformatic anal...

Slate, J.; Hale, M. C.; Birkhead, T. R.

2007-01-01

260

Relaxation of magnetic field relative to plasma density revealed from microwave zebra patterns associated with solar flares  

OpenAIRE

It is generally considered that the emission of microwave zebra pattern (ZP) structures requires high density and high temperatures, which is similar to the situation of the flaring region where primary energy releases. Therefore, the parameters analysis of ZPs may reveal the physical conditions of the flaring source region. This work investigates the variations of 74 microwave ZP structures observed by Chinese Solar Broadband Radio Spectrometer (SBRS/Huairou) at 2.6-3.8 GHz...

Yu, Sijie; Yan, Yihua; Tan, Baolin

2012-01-01

261

Histological Changes Induced in Gonads, Liver and Kidney of Zebra Fish (Danio Rerio) Under the Effect Octylphenol (OP)  

OpenAIRE

World-wide researches during the last years are focused upon the negative effects caused by the natural chemical compounds and anthropogenic compounds, already being demonstrated that a great part of them change the endocrine control over reproduction at different species. The issue studied by our team is concerned with the histological changes that appear within liver, kidney and gonadal development at the zebra fish (Danio rerio), exposed to octylphenol from 21-115 days

Gabi Dumitrescu; Liliana Petculescu Ciochina; Sorin Voia; Dorel Dronca; Liliana Boca

2010-01-01

262

Using Zebra-speech to study sequential and simultaneous speech segregation in a cochlear-implant simulation.  

Science.gov (United States)

Previous studies have suggested that cochlear implant users may have particular difficulties exploiting opportunities to glimpse clear segments of a target speech signal in the presence of a fluctuating masker. Although it has been proposed that this difficulty is associated with a deficit in linking the glimpsed segments across time, the details of this mechanism are yet to be explained. The present study introduces a method called Zebra-speech developed to investigate the relative contribution of simultaneous and sequential segregation mechanisms in concurrent speech perception, using a noise-band vocoder to simulate cochlear implants. One experiment showed that the saliency of the difference between the target and the masker is a key factor for Zebra-speech perception, as it is for sequential segregation. Furthermore, forward masking played little or no role, confirming that intelligibility was not limited by energetic masking but by across-time linkage abilities. In another experiment, a binaural cue was used to distinguish the target and the masker. It showed that the relative contribution of simultaneous and sequential segregation depended on the spectral resolution, with listeners relying more on sequential segregation when the spectral resolution was reduced. The potential of Zebra-speech as a segregation enhancement strategy for cochlear implants is discussed. PMID:23297922

Gaudrain, Etienne; Carlyon, Robert P

2013-01-01

263

Within-year differences in reproductive investment in laboratory zebra finches ( Taeniopygia guttata), an opportunistically breeding bird  

Science.gov (United States)

Reproduction in opportunistically breeding bird species has traditionally been considered non-seasonal with individuals taking advantage of favourable environmental conditions as they arise. However, some studies imply that this opportunistic breeding may be superimposed on an underlying seasonality, which has effects on the readiness to breed when conditions are favourable. The zebra finch ( Taeniopygia guttata) is the classic opportunistic breeder and widely used as such in studies. In a series of laboratory-based breeding experiments, we found evidence to suggest that there are seasonal differences in maternal reproductive investment in the zebra finch even when photoperiod, temperature, relative humidity and diet were held constant. Females showed highly significant seasonal differences in clutch size and egg mass with laying order. Clutch size showed a spring/summer peak typical of multi-brooded species in the wild. There was also a significant increase in egg mass with laying order in all seasons except winter. This variation in breeding parameters with season may allow females to adjust investment depending on the potential fitness returns from a given reproductive attempt. These findings also raise a warning about interpreting results of multiple zebra finch breeding experiments that have been carried out in different seasons.

Williamson, Kathryn; Gilbert, Lucy; Rutstein, Alison N.; Pariser, Emma C.; Graves, Jeff A.

2008-12-01

264

Physiological and behavioral responses to an acute-phase response in zebra finches: immediate and short-term effects.  

Science.gov (United States)

Activation of the immune system to clear pathogens and mitigate infection is a costly process that might incur fitness costs. When vertebrates are exposed to pathogens, their first line of defense is the acute-phase response (APR), which consists of a suite of physiological and behavioral changes. The dynamics of the APR are relatively well investigated in mammals and domesticated birds but still rather unexplored in passerine birds. In this study, we injected male zebra finches (Taeniopygia guttata) with a bacterial endotoxin (lipopolysaccharide [LPS]) to assess the potential physiological, immunological, and behavioral responses during the time course of an APR and also to record any potential short-term effects by measuring the birds during the days after the expected APR. We found that LPS-injected zebra finches decreased activity and gained less body mass during the APR, compared to control individuals. In addition, LPS-injected birds increased their production of LPS-reactive antibodies and reduced their metabolic rate during the days after the expected APR. Our results show that zebra finches demonstrate sickness behaviors during an APR but also that physiological effects persist after the expected time course of an APR. These delayed effects might be either a natural part of the progression of an APR, which is probably true for the antibody response, or a short-term carryover effect, which is probably true for the metabolic response. PMID:24642546

Sköld-Chiriac, Sandra; Nord, Andreas; Nilsson, Jan-Åke; Hasselquist, Dennis

2014-01-01

265

Producción secundaria e índice de condición en Arca zebra (Mollusca: Bivalvia del Golfo de Cariaco, Venezuela  

Directory of Open Access Journals (Sweden)

Full Text Available Se estudió la biomasa, producción secundaria e índice de condición del bivalvo Arca zebra, desde agosto, 1984 hasta agosto, 1985 en Pariche, localidad situada en la costa norte del Golfo de Cariaco, Venezuela. La densidad promedio fue de 37 ind.m-2, con una mayor abundancia a 3 m de profundidad (49.75 ind.m-2. La estructura poblacional es estable con reclutamientos en octubre, diciembre 1984 y junio 19885. Los valores bimensuales de biomasa oscilaron entre 189.86 g Ps m-2 (agosto-84 y 28.51 g Ps m-2 (octubre-84, con un promedio de 93.69 g Ps m-2, y no presentaron diferencias significativas (Fs, P 0.05. Utilizando un método para poblaciones con reproducción contínua y edades no separables, se obtuvo una producción secundaria de 131.61 g Ps. m-2.año-1, y la relación P/B de1.41 año-1. La mayor producción secundaria ocurrió entre febrero 1985 y agosto 1985 (65%, con el mayor aporte por el intervalo 60.00-79.95 mm (45.73%. Se observaron cambios significativos en la variación mensual del índice de condición (IC= (Ps/ Ph x100 en dos clases de tallas analizadas, presentando los valores más altos en julio de 1985 (26.84% y el mínimo en enero de 1985 (16.31%.Production and condition index of a turkeywing (Arca zebra population were studied from August 1984 to August 1985 in Pariche, Cariaco Gulf, Venezuela. Production was studied through bimonthly collections using a method designed for populations with continuous reproduction and indistinguishable age classes. The population distribution was stable with a mean density of 37 ind.m-2. A production of 131.61 g dry weight m-2.year-1 was calcuclated from data on density, biomass and weight increase along the year. Highest production was between February 1985 and August 1985 (65% and concentrated in individuals 60.00-79.95 mm long (45.73%. There was large seasonal variation in the mean monthly condition index (IC= (Ps/Ph x100 in the two size classes examined: it reached a maximum in July 1985 (26.84% and a minimum in January 1985 (16.31%.

Antulio Prieto Arcas

2001-06-01

266

Speed of exploration and risk-taking behavior are linked to corticosterone titres in zebra finches.  

Science.gov (United States)

The existence of consistent individual differences in behavioral strategies ("personalities" or coping styles) has been reported in several animal species. Recent work in great tits has shown that such traits are heritable and exhibit significant genetic variation. Free-living birds respond to environmental stresses by up-regulating corticosterone production. Behavior during mild stress can occur in accordance to two types of coping styles, i.e. active and passive. Using artificially selected lines of zebra finches that vary in the amount of corticosterone produced in response to a manual restraint stressor we ran three "personality" experiments. We show that birds in the different corticosterone lines differ in their exploratory and risk-taking behaviors. There was an increase in exploratory behavior as corticosterone titre increased but only in the low corticosterone line. Birds in high corticosterone line showed greater risk-taking behavior than birds in the other lines. Thus, in general, higher levels of circulating corticosterone following a mild stress result in greater exploratory behavior and greater risk taking. This study shows that lines of animals selected for endocrine hormonal responses differ in their "coping" styles or "personalities". PMID:17678929

Martins, Thaís L F; Roberts, Mark L; Giblin, Isobel; Huxham, Rebecca; Evans, Matthew R

2007-11-01

267

Cave crawling in zebra Finch skulls : Which anatomical structures constitute the functional intraaural Canal?  

DEFF Research Database (Denmark)

The middle ears of birds are acoustically coupled through an air-filled interaural canal, often illustrated and modelled as a simple tube. It allows sound to propagate through the skull from one ear to the other and considerably enhance the cues for directional hearing by interaction with the external sound field driving the eardrum vibrations. Theoretically, different combinations of frequency dependent gains and delays of sound in the interaural canal can produce very different directionalities of the ears but it still remains uncertain how interaural transmission gain and delay can be shaped by anatomical adaptations during evolution. A closer inspection of the zebra finch cranium using micro-CT scanning reveals that not only is IAC trabeculated and irregularly shaped but it also communicates with a set of highly complex, air-filled canals in the skull extending to the base of the beak. We tested the possible influence of these communicating cavities by measuring eardrum directionality and interaural transmission before and after filling the frontal cavities with dyed fat but found no dramatic effects. We will discuss what function the cavities serve and whether the ICA should be represented by a simple tube in future models

Larsen, Ole Næsbye; Salomon, Rasmus

268

Auditory synapses to song premotor neurons are gated off during vocalization in zebra finches.  

Science.gov (United States)

Songbirds use auditory feedback to learn and maintain their songs, but how feedback interacts with vocal motor circuitry remains unclear. A potential site for this interaction is the song premotor nucleus HVC, which receives auditory input and contains neurons (HVCX cells) that innervate an anterior forebrain pathway (AFP) important to feedback-dependent vocal plasticity. Although the singing-related output of HVCX cells is unaltered by distorted auditory feedback (DAF), deafening gradually weakens synapses on HVCX cells, raising the possibility that they integrate feedback only at subthreshold levels during singing. Using intracellular recordings in singing zebra finches, we found that DAF failed to perturb singing-related synaptic activity of HVCX cells, although many of these cells responded to auditory stimuli in non-singing states. Moreover, in vivo multiphoton imaging revealed that deafening-induced changes to HVCX synapses require intact AFP output. These findings support a model in which the AFP accesses feedback independent of HVC. DOI: http://dx.doi.org/10.7554/eLife.01833.001. PMID:24550254

Hamaguchi, Kosuke; Tschida, Katherine A; Yoon, Inho; Donald, Bruce R; Mooney, Richard

2014-01-01

269

An assessment of total and leachable contaminants in zebra mussels (Dreissena polymorpha) from Lake Erie  

Energy Technology Data Exchange (ETDEWEB)

Samples of zebra mussels, Dreissena polymorpha, from populations infesting two power generating stations on Lake Erie were subjected to tests assessing the potential for leaching of metals and other (inorganic and organic) contaminants from mussel waste destined for disposal in conventional landfills. These tests revealed that mussels collected from Ontario Hydro's Nanticoke Thermal Generating Station and Niagara Mohawk Power Corporation's Dunkirk Steam Station did not release hazardous materials in excess of limits set forth in Canadian and U.S. regulations, respectively. A variety of metals and inorganic materials leached from Nanticoke mussels at levels significantly lower than the registration limits for those analytes. Detectable levels of chloroform (0.080 mg/liter) and barium (3.3 mg/liter) leached from Dunkirk mussels at > 30-fold lower levels than U.S. regulatory action limits for those materials. Whole body analyses revealed a lack of detectable levels of herbicides and pesticides in either population with a variety of metals and inorganic constituents in all samples from both populations. The physiological condition of Dunkirk mussels appeared to be consistent with that of other Lake Erie populations based on percentage water and total fat content of soft tissues.

Doherty, F.G.; Evans, D.W.; Neuhauser, E.F. (Syracuse Research Corp., NY (United States))

1993-06-01

270

Evaluation of several priority pollutants in zebra mussels (Dreissena polymorpha) in the largest Italian subalpine lakes  

International Nuclear Information System (INIS)

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. - Significant levels of DDTs and PCBs are still present in the Italian subalpine great lakes

271

EVALUATION OF BIOTIC AND TREATMENT FACTORS RELATING TO BACTERIAL CONTROL OF ZEBRA MUSSELS  

Energy Technology Data Exchange (ETDEWEB)

Testing over the last quarter has indicated the following regarding control of zebra mussels with bacterium Pseudomonas fluorescens strain CL0145A: (1) the concentration of bacteria suspended in water is directly correlated with mussel kill; (2) the ratio of bacterial mass per mussel, if too low, could limit mussel kill; a treatment must be done at a high enough ratio so that mussels do not deplete all the suspended bacteria before the end of the desired exposure period; (3) bacteria appear to lose almost all their toxicity after suspension for 24 hr in highly oxygenated water; (4) in a recirculating pipe system, the same percentage mussel kill will be achieved irrespective of whether all the bacteria are applied at once or divided up and applied intermittently in smaller quantities over a 10-hr period. Since this is the fourth quarterly report, a summation of all test results over the last twelve months is provided as a table in this report. The table includes the above-mentioned fourth-quarter results.

Daniel P. Molloy

2002-04-30

272

EVALUATION OF BIOTIC AND TREATMENT FACTORS RELATING TO BACTERIAL CONTROL OF ZEBRA MUSSELS  

International Nuclear Information System (INIS)

Testing over the last quarter has indicated the following regarding control of zebra mussels with bacterium Pseudomonas fluorescens strain CL0145A: (1) the concentration of bacteria suspended in water is directly correlated with mussel kill; (2) the ratio of bacterial mass per mussel, if too low, could limit mussel kill; a treatment must be done at a high enough ratio so that mussels do not deplete all the suspended bacteria before the end of the desired exposure period; (3) bacteria appear to lose almost all their toxicity after suspension for 24 hr in highly oxygenated water; (4) in a recirculating pipe system, the same percentage mussel kill will be achieved irrespective of whether all the bacteria are applied at once or divided up and applied intermittently in smaller quantities over a 10-hr period. Since this is the fourth quarterly report, a summation of all test results over the last twelve months is provided as a table in this report. The table includes the above-mentioned fourth-quarter results

273

ZebraBeat: a flexible platform for the analysis of the cardiac rate in zebrafish embryos  

Science.gov (United States)

Heartbeat measurement is important in assesssing cardiac function because variations in heart rhythm can be the cause as well as an effect of hidden pathological heart conditions. Zebrafish (Danio rerio) has emerged as one of the most useful model organisms for cardiac research. Indeed, the zebrafish heart is easily accessible for optical analyses without conducting invasive procedures and shows anatomical similarity to the human heart. In this study, we present a non-invasive, simple, cost-effective process to quantify the heartbeat in embryonic zebrafish. To achieve reproducibility, high throughput and flexibility (i.e., adaptability to any existing confocal microscope system and with a user-friendly interface that can be easily used by researchers), we implemented this method within a software program. We show here that this platform, called ZebraBeat, can successfully detect heart rate variations in embryonic zebrafish at various developmental stages, and it can record cardiac rate fluctuations induced by factors such as temperature and genetic- and chemical-induced alterations. Applications of this methodology may include the screening of chemical libraries affecting heart rhythm and the identification of heart rhythm variations in mutants from large-scale forward genetic screens.

de Luca, Elisa; Zaccaria, Gian Maria; Hadhoud, Marwa; Rizzo, Giovanna; Ponzini, Raffaele; Morbiducci, Umberto; Santoro, Massimo Mattia

2014-05-01

274

Environmental and genetic control of brain and song structure in the zebra finch.  

Science.gov (United States)

Birdsong is a classic example of a learned trait with cultural inheritance, with selection acting on trait expression. To understand how song responds to selection, it is vital to determine the extent to which variation in song learning and neuroanatomy is attributable to genetic variation, environmental conditions, or their interactions. Using a partial cross fostering design with an experimental stressor, we quantified the heritability of song structure and key brain nuclei in the song control system of the zebra finch and the genotype-by-environment (G × E) interactions. Neuroanatomy and song structure both showed low levels of heritability and are unlikely to be under selection as indicators of genetic quality. HVC, in particular, was almost entirely under environmental control. G × E interaction was important for brain development and may provide a mechanism by which additive genetic variation is maintained, which in turn may promote sexual selection through female choice. Our study suggests that selection may act on the genes determining vocal learning, rather than directly on the underlying neuroanatomy, and emphasizes the fundamental importance of environmental conditions for vocal learning and neural development in songbirds. PMID:24102614

Woodgate, Joseph L; Buchanan, Katherine L; Bennett, Andrew T D; Catchpole, Clive K; Brighton, Roswitha; Leitner, Stefan

2014-01-01

275

Lifelong exposure to methylmercury disrupts stress-induced corticosterone response in zebra finches (Taeniopygia guttata).  

Science.gov (United States)

Mercury can disrupt the endocrine systems of mammals and fish, but little is known about its effects on avian hormones. The authors employed an experimental manipulation to show that methylmercury suppresses the stress-induced corticosterone response in birds, an effect previously unreported in the literature. Corticosterone regulates many normal metabolic processes, such as the maintenance of proper blood glucose levels during stressful daily fasting; an inability to increase corticosterone levels in response to stressors renders a bird less able to face a wide array of environmental challenges. The authors studied reproductively mature zebra finches that had been exposed to 0.0?µg/g, 0.3?µg/g, 0.6?µg/g, 1.2?µg/g, or 2.4?µg/g (wet wt) dietary methylmercury throughout their life (i.e., from the egg onward). In contrast to some field studies, the present study found no significant change in baseline plasma corticosterone concentrations attributable to chronic methylmercury exposure. However, a comparison between the baseline corticosterone levels and levels after 30?min of handling stress revealed that the ability of birds to mount a stress response was reduced with increasing blood total mercury concentration. These results are consistent with adrenal corticoid disruption caused by chronic mercury exposure and mirror a similar study on free-living nestling songbirds exposed to environmental mercury. PMID:24436046

Moore, Christina S; Cristol, Daniel A; Maddux, Sarah L; Varian-Ramos, Claire W; Bradley, Eric L

2014-05-01

276

Maternal antibody transfer can lead to suppression of humoral immunity in developing zebra finches (Taeniopygia guttata).  

Science.gov (United States)

Maternally transferred antibodies have been documented in a wide range of taxa and are thought to adaptively provide protection against parasites and pathogens while the offspring immune system is developing. In most birds, transfer occurs when females deposit immunoglobulin Y into the egg yolk, and it is proportional to the amount in the female's plasma. Maternal antibodies can provide short-term passive protection as well as specific and nonspecific immunological priming, but high levels of maternal antibody can result in suppression of the offspring's humoral immune response. We injected adult female zebra finches (Taeniopygia guttata) with one of two antigens (lipopolysaccharide [LPS] or keyhole limpet hemocyanin [KLH]) or a control and then injected offspring with LPS, KLH, or a control on days 5 and 28 posthatch to examine the impact of maternally transferred antibodies on the ontogeny of the offspring's humoral immune system. We found that offspring of females exposed to KLH had elevated levels of KLH-reactive antibody over the first 17-28 days posthatch but reduced KLH-specific antibody production between days 28 and 36. We also found that offspring exposed to either LPS or KLH exhibited reduced total antibody levels, compared to offspring that received a control injection. These results indicate that high levels of maternal antibodies or antigen exposure during development can have negative repercussions on short-term antibody production and may have long-term fitness repercussions for the offspring. PMID:25244385

Merrill, Loren; Grindstaff, Jennifer L

2014-01-01

277

Inner-shell radiation from wire array implosions on the Zebra generator  

Energy Technology Data Exchange (ETDEWEB)

Implosions of brass wire arrays on Zebra have produced L-shell radiation as well as inner-shell K? and K? transitions. The L-shell radiation comes from ionization stages around the Ne-like charge state that is largely populated by a thermal electron energy distribution function, while the K-shell photons are a result of high-energy electrons ionizing or exciting an inner-shell (1s) electron from ionization stages around Ne-like. The K- and L-shell radiations were captured using two time-gated and two axially resolved time-integrated spectrometers. The electron beam was measured using a Faraday cup. A multi-zone non-local thermodynamic equilibrium pinch model with radiation transport is used to model the x-ray emission from experiments for the purpose of obtaining plasma conditions. These plasma conditions are used to discuss some properties of the electron beam generated by runaway electrons. A simple model for runaway electrons is examined to produce the K? radiation, but it is found to be insufficient.

Ouart, N. D.; Giuliani, J. L.; Dasgupta, A. [Plasma Physics Division, Naval Research Laboratory, Washington, District of Columbia 20375 (United States); Safronova, A. S.; Kantsyrev, V. L.; Esaulov, A. A.; Shrestha, I.; Weller, M. E.; Shlyaptseva, V.; Osborne, G. C.; Stafford, A.; Keim, S. [Physics Department, University of Nevada, Reno, Nevada 89557 (United States); Apruzese, J. P. [Consultant to NRL through Engility Corp., Chantilly, Virginia 20151 (United States); Clark, R. W. [Berkeley Research Associates, Beltsville, Maryland 20705 (United States)

2014-03-15

278

Measurements of plasma conditions in precursor plasmas at the 1-MA Zebra facility  

Science.gov (United States)

Precursor plasmas, both the early time precursor flow of mass and the accumulation of this material on axis, were observed on many z-pinch experiments at various facilities, including low current (15 MA, Z) facilities. The impact of these precursors on stagnated plasmas, and targets such as those used for ICF experiments, is still under evaluation. Experiments were performed at the UNR 1-MA, 100ns Zebra facility to study these precursor plasmas with Cu wire arrays. Significant precursor radiation at photon energies > 1 keV was observed on filtered PCDs. Te and ne of the precursor radiation were obtained from modeling of time-resolved spectroscopy of the Cu L-shell emissions for 6 wires on 12mm diameter loads. The precursor plasma temperatures are consistently >250eV. Time resolved pinhole images were also collected, which show bright spots of radiation along the axial length of the pinch. Sandia is a multi-program laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the US DOE under Contract DE-AC04-94AL85000. Work was also supported by the DOE/NNSA Coop. agr. DE-FC52-06NA27616, 06NA27588, 06NA27586, and by fellowship from the NPSC with SNL.

Ouart, N. D.; Coverdale, C. A.; Safronova, A. S.; Kantsyrev, V. L.; Williamson, K. M.; Shrestha, I.; Osborne, G. C.; Deeney, C.

2007-11-01

279

EFFECTS OF ORGANOPHOSPHATES ON ACUTE POISONING AND ACETYL CHOLINESTERASE INHIBITION IN ZEBRA FISH  

Directory of Open Access Journals (Sweden)

Full Text Available Organophosphates (Ops. are the most widely used insecticides available today. These are a group of insecticides used in chemical sprays to kill bugs, and insects in orchards, vineyards, vegetables and cereal crops. The present study examined effects of the pesticide Methyl parathion, Dichlorvos and Chlorpyrifos on adult zebra fish were exposed to various concentrations (5, 10 & 25mg/L for 24 and 48hrs acute toxic study. Chlorpyrifos showed mortality in all concentrations and Methyl parathion and Dichlorvos showed the same in 25 mg/L. LC 50 value for Methyl parathion and Dichlorvos was 5 & 10 mg/L respectively. The total protein, LPO content was increased except SOD, Catalase in the brain tissue of the treated fishes.  There was no significant decrease in the GPX activity at 5ppm test groups. The GPX activity decreased significantly in test group treated with 10ppm and a significant difference was found between 5ppm and 10ppm test groups. The histopathological studies of brain tissue showed that neuronal degeneration and tissue damages in the brain of treated fishes when compared with the control. Ops. produce toxicity by inhibiting the cholinesterase enzymes in the nervous system. Monitoring of acetyl cholinesterase (AChE inhibition has been widely used in terrestrial and freshwater aquatic systems as an indicator of OP exposure and effects.

TH Sukirtha* MV Usharani

2013-03-01

280

Analytical developments for the speciation of uranium in zebra fish (Danio rerio) gills after exposure  

International Nuclear Information System (INIS)

The objective of this thesis is to study the cellular compartmentalization and the chelation of uranium (U) by cytosolic proteins of gill cells of the zebra fish (Danio rerio, model specie in aquatic toxicology) under different direct exposure conditions (chronic vs. acute, 20 and 250 ?g.L-1). This study required the development of hyphenated techniques (SEC, IEF off-gel, RP-UHPLC for the separation, ICP-SFMS, ESI-FTMS/MS for the detection) with the main challenges of maintaining the non-covalent U-biomolecule interactions and enhancing sensitivity for the analysis of environmentally relevant samples. After extraction, 24% to 32% of the total U detected in the gills were present in the cytosolic fraction, in which the U distribution on the biomolecules (as a function of their MW and pI) varied depending on the exposure level. Finally, U target biomolecules mapping allowed us (i) to highlight a particular affinity of U for acidic and/or P-containing proteins and (ii) to identify 24 protein candidates for U binding. (author)

281

Models of radiation yield from wire array implosion at 1 MA Zebra generator  

Science.gov (United States)

The snowplow and thin shell models that have the analytical solutions in zero dimensions are linked with the ideal magnetohydrodynamic (MHD) and radiation MHD codes to calculate the radiation yield from the imploding wire array loads at 1MA Zebra generator. Radiation MHD simulations show that the strong radiation cooling affects plasma dynamics at all stages of the implosion and drives plasma into the radiative collapse at the final stage of the implosion. Being applied to the implosion of an Al wire array with the mass per unit length 3.82?g/mm, these simulations show that the thermalization of the kinetic energy can be essentially completed when the radius of the imploding pinch shrinks below ˜10?m. If we assume such a perfect compression, then the plasma energy gain will be 10kJ with total radiation yield of about 5kJ, while the emitted radiation spectrum will be blackbody-like with an equilibrium temperature of 200eV. The only effective mechanism of energy coupling for the imploding plasma, driven by the magnetic piston, is the inductive work of the magnetic field due to the motional impedance. However, the mechanism of anomalous plasma heating, acting in the plasma fraction that was left behind the collapsing current sheath, can couple additional energy into the plasma and can explain the variety of radiation performance features. An adequate model of the radiation yield should consider the stagnating z pinch as an object with strong density and temperature gradients.

Esaulov, Andrey

2006-04-01

282

Adverse effects induced by ecgonine methyl ester to the zebra mussel: a comparison with the benzoylecgonine.  

Science.gov (United States)

Cocaine and its metabolites are the prevalent psychotropic substances in aquatic environment. However, to date the knowledge on their adverse effects to non-target organisms is inadequate. The aims of this study were to investigate sub-lethal effects induced by the ecgonine methyl ester (EME) to the freshwater bivalve Dreissena polymorpha and to compare its toxicity to that by benzoylecgonine (BE), the other main cocaine metabolite. EME sub-lethal effects were investigated by 14 days in-vivo exposures and a multi-biomarker approach. Slight variations in biomarker responses were found at 0.15 ?g/L treatment. 0.5 ?g/L EME treatment induced destabilization of lysosome membranes, an overall inactivation of defense enzymes, increases in lipid peroxidation, protein carbonylation and DNA fragmentation, but no variations in fixed genetic damage. The use of a biomarker response index (BRI) showed that at 0.5 ?g/L both cocaine metabolites had the same toxicity to zebra mussels specimens. PMID:23974167

Parolini, Marco; Binelli, Andrea

2013-11-01

283

A comparative study of the sulfation of bile acids and a bile alcohol by the Zebra danio (Danio rerio) and human cytosolic sulfotransferases (SULTs)  

OpenAIRE

The current study was designed to examine the sulfation of bile acids and bile alcohols by the Zebra danio (Danio rerio) SULTs in comparison with human SULTs. A systematic analysis using the fifteen Zebra danio SULTs revealed that SULT3 ST2 and SULT3 ST3 were the major bile acid/alcohol-sulfating SULTs. Among the eleven human SULTs, only SULT2A1 was found to be capable of sulfating bile acids and bile alcohols. To further investigate the sulfation of bile acids and bile alcohols by the two Ze...

Kurogi, Katsuhisa; Krasowski, Matthew D.; Injeti, Elisha; Liu, Ming-yih; Williams, Frederick E.; Sakakibara, Yoichi; Suiko, Masahito; Liu, Ming-cheh

2011-01-01

284

Mitochondrial uncoupling as a regulator of life-history trajectories in birds: an experimental study in the zebra finch.  

Science.gov (United States)

Mitochondria have a fundamental role in the transduction of energy from food into ATP. The coupling between food oxidation and ATP production is never perfect, but may nevertheless be of evolutionary significance. The 'uncoupling to survive' hypothesis suggests that 'mild' mitochondrial uncoupling evolved as a protective mechanism against the excessive production of damaging reactive oxygen species (ROS). Because resource allocation and ROS production are thought to shape animal life histories, alternative life-history trajectories might be driven by individual variation in the degree of mitochondrial uncoupling. We tested this hypothesis in a small bird species, the zebra finch (Taeniopygia guttata), by treating adults with the artificial mitochondrial uncoupler 2,4-dinitrophenol (DNP) over a 32-month period. In agreement with our expectations, the uncoupling treatment increased metabolic rate. However, we found no evidence that treated birds enjoyed lower oxidative stress levels or greater survival rates, in contrast to previous results in other taxa. In vitro experiments revealed lower sensitivity of ROS production to DNP in mitochondria isolated from skeletal muscles of zebra finch than mouse. In addition, we found significant reductions in the number of eggs laid and in the inflammatory immune response in treated birds. Altogether, our data suggest that the 'uncoupling to survive' hypothesis may not be applicable for zebra finches, presumably because of lower effects of mitochondrial uncoupling on mitochondrial ROS production in birds than in mammals. Nevertheless, mitochondrial uncoupling appeared to be a potential life-history regulator of traits such as fecundity and immunity at adulthood, even with food supplied ad libitum. PMID:25063856

Stier, Antoine; Bize, Pierre; Roussel, Damien; Schull, Quentin; Massemin, Sylvie; Criscuolo, François

2014-10-01

285

Plasma sex steroids and tissue aromatization in hatchling zebra finches: implications for the sexual differentiation of singing behavior.  

Science.gov (United States)

One of the best examples for sex hormone regulation of brain development is found in songbirds. In zebra finches, only males sing because of striking sex differences in the neural circuitry that controls songs. Because developing females treated with estradiol (E2) develop a masculine song system, E2 is considered the normal masculinizing hormone. However, questions about the role of E2 in male development persist, because E2 treatments that masculinize song can demasculinize other sexual behaviors, and there exists contradictory evidence for high levels of circulating E2 in developing males. We remeasured plasma steriods in zebra finches during the first 13 days after hatching. E2 circulated at low levels, and there were no sex differences in circulating E2, estrone, testosterone, androstenedione, or dihydrotestosterone. We also measured aromatase activity [( 3H]androstenedione conversion to [3H]estrone and [3H]E2) in gonad, adrenal, brain, and other tissues of hatchlings. Aromatase was abundant in ovary, but was not definitively detected in testes, adrenals, or other nonneural tissues of males. Aromatase was also found in diencephalon and in high amounts in telencephalon, but sex differences were not detected in whole brain or cellular subfractions of telencephalon. Because ovarian steroidogenesis is high, it may be involved in differentiation of the female zebra finch, as in nonpasserine birds. By contrast, the functional estrogen necessary for masculinization of song is most likely derived from brain, supplied with substrate from the adrenals. The puzzle remains why the song system is not masculinized in females, who possess high levels of aromatizable androgens and telencephalic aromatase. PMID:1727704

Schlinger, B A; Arnold, A P

1992-01-01

286

Water Quality Impacts and Indicators of the Metabolic Activity of the Zebra Mussel Invasion of the Seneca River  

Science.gov (United States)

The conspicuous shifts in summertime values of common measures of water qualify that have persisted for 10 years (1993 to 2002) in the Seneca River, New York, as a result of the zebra mussel invasion are documented. Resolution of patterns in time and space is supported by water quality monitoring that extends back to the late 1970s. Patterns are evaluated to describe the stability of impacts and quantify metabolic activity of the invader. The water quality impacts that have persisted unabated for 10 years since the invasion are the most severe documented for a river in North America. Changes in summer median conditions since the invasion include: (1) a 16-fold decrease in chlorophyll concentration (Chl), (2) a 2.5-fold increase in Secchi disc transparency, (3) a 17-fold increase in soluble reactive phosphorus concentration, (4) a 3.7-fold increase in total ammonia concentration, (5) a greater than 25 percent decrease in dissolved oxygen (DO) concentration, and (6) a decrease in pH of 0.55 units. The strength of these signatures has been driven by anthropogenic influences that include upstream nutrient loading and morphometric modifications of the river, and the functioning of Cross Lake, through which the river flows. This hypereutrophic lake sustains dense zebra mussel populations and related water quality impacts in the river downstream of the lake outflow by acting as a source of veligers and suitable food for this bivalve. Evidence is presented that levels of metabolic activity of the zebra mussel in this river have been resource limited, manifested through increased consumption of Chl and DO with increased delivery of these constituents in the lake's outflow.

Effler, Steven W.; Matthews, David A.; Brooks-Matthews, Carol M.; Perkins, Mary Gail; Siegfried, Clifford A.; Hassett, James M.

2004-06-01

287

Isolation-dependent enhancement of 14C-2-deoxyglucose uptake in the forebrain of zebra finch males  

OpenAIRE

In a previous study (H. J. Bischof and K. Herrmann (1986), Behavioral Brain Research, 21, 215-221) we demonstrated that four forebrain areas of the zebra finch male are activated in situations which arouse the animal, for example when the birds are chased around the cage or when they are exposed to a female. These areas, the hyperstriatum accessorium-dorsale (HAD), a part of the medial neo-hyperstriatum (MNH), the lateral neo-hyperstriatum (LNH), and a portion of the caudal archi-neostriatum ...

Bischof, Hans-joachim; Herrmann, Kathrin

1988-01-01

288

Defensin of the zebra mussel (Dreissena polymorpha): molecular structure, in vitro expression, antimicrobial activity, and potential functions.  

Science.gov (United States)

A 409 bp full length defensin gene was cloned and sequenced based on an expressed sequence tag (EST) obtained from a normalized zebra mussel (Dreissena polymorpha) foot cDNA library developed in our laboratory. The D. polymorpha defensin (Dpd) gene encoded a peptide with 76 amino acid residues. The mature Dpd contains 54 amino acids with a fully functional insect defensin A domain. Homologue searching against GenBank database suggested that this Dpd was phylogenetically close to defensins from a group of insects with six conserved cysteine residues. Predicted with homology-modeling method, the three-dimensional structure of Dpd also demonstrated a significant similarity with insect defensin A. The recombinant Dpd was in vitro expressed through an Escherichia coli expression system. The antimicrobial activities of the refolded recombinant Dpd were found against the growth of Morganella sp., Plesiomonas shigelloides, Edwardsiella tarda, E. coli and Staphylococcus aureus aureus (ATCC12598) with the minimal inhibition concentration (MIC) 0.35, 0.43, 1.16, 6.46, and 30.39 microM, respectively. However, with less than 50 microM no detectable inhibition activities were observed against the other four Gram-negative bacteria (Aeromonas salmonicida salmonicida, Motile Aeromonas, Flavobacterium sp., Pseudomonas fluorescens, Shewanella putrifaciens), as well as the other Gram-positive bacteria (Bacillus megaterium ATCC14581, Carnobacterium maltaromaticum ATCC27865, Enterococcus faecalis ATCC19433, and Micrococcus leteus ATCC4698), and the yeast Saccharomyces cerevisiae. The RNA fluorescent in situ hybridization (FISH) of Dpd in the zebra mussel suggested that the Dpd was expressed in a variety of tissues, such as foot, retractor muscle, ctenidium, mantle, hemocytes, gonad, digestive gland, and intestine. By using the quantitative PCR, the expression level of Dpd in the zebra mussel foot was the highest, followed by the muscle. By comparing the amount of Dpd transcripts in the zebra mussel foot under two different byssogenesis conditions (byssogenesis and non-byssogenesis) with qPCR, we found that the higher expression levels of Dpd were always associated with the byssogenesis status from 2 to 4 days after the start of byssogenesis. Findings of this study suggest that the expression of the Dpd gene was upregulated in vivo by byssogeneis, and by hemocytes in vitro upon stimulation with microbial antigens. PMID:20537393

Xu, Wei; Faisal, Mohamed

2010-07-01

289

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 farmers in Mexico and New Zealand. ZC is associated with ‘Candidatus Liberibacter solanacearum’, a fastidious alpha-proteobacterium that is transmitted by a phloem-feeding psyllid vector, Bactericera cockerelli Sulc. Research on this disease has been hampered by a lack of robust culture methods and paucity of genome sequence information for ‘Ca. L. solanacearum’. Here we present the sequence of the 1.26 Mbp metagenome of ‘Ca. L. solanacearum’, based on DNA isolated from potato psyllids. The coding inventory of the ‘Ca. L. solanacearum’ genome was analyzed and compared to related Rhizobiaceae to better understand ‘Ca. L. solanacearum’ physiology and identify potential targets to develop improved treatment strategies. This analysis revealed a number of unique transporters and pathways, all potentially contributing to ZC pathogenesis. Some of these factors may have been acquired through horizontal gene transfer. Taxonomically, ‘Ca. L. solanacearum’ is related to ‘Ca. L. asiaticus’, a suspected causative agent of citrus huanglongbing, yet many genome rearrangements and several gene gains/losses are evident when comparing these two Liberibacter. species. Relative to ‘Ca. L. asiaticus’, ‘Ca. L. solanacearum’ probably has reduced capacity for nucleic acid modification, increased amino acid and vitamin biosynthesis functionalities, and gained a high-affinity iron transport system characteristic of several pathogenic microbes. PMID:21552483

Lin, Hong; Civerolo, Edwin L.; Chen, Chuanwu; Duan, Yongping; Zhou, Lijuan; Vahling, Cheryl M.

2011-01-01

290

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 farmers in Mexico and New Zealand. ZC is associated with 'Candidatus Liberibacter solanacearum', a fastidious alpha-proteobacterium that is transmitted by a phloem-feeding psyllid vector, Bactericera cockerelli Sulc. Research on this disease has been hampered by a lack of robust culture methods and paucity of genome sequence information for 'Ca. L. solanacearum'. Here we present the sequence of the 1.26 Mbp metagenome of 'Ca. L. solanacearum', based on DNA isolated from potato psyllids. The coding inventory of the 'Ca. L. solanacearum' genome was analyzed and compared to related Rhizobiaceae to better understand 'Ca. L. solanacearum' physiology and identify potential targets to develop improved treatment strategies. This analysis revealed a number of unique transporters and pathways, all potentially contributing to ZC pathogenesis. Some of these factors may have been acquired through horizontal gene transfer. Taxonomically, 'Ca. L. solanacearum' is related to 'Ca. L. asiaticus', a suspected causative agent of citrus huanglongbing, yet many genome rearrangements and several gene gains/losses are evident when comparing these two Liberibacter. species. Relative to 'Ca. L. asiaticus', 'Ca. L. solanacearum' probably has reduced capacity for nucleic acid modification, increased amino acid and vitamin biosynthesis functionalities, and gained a high-affinity iron transport system characteristic of several pathogenic microbes. PMID:21552483

Lin, Hong; Lou, Binghai; Glynn, Jonathan M; Doddapaneni, Harshavardhan; Civerolo, Edwin L; Chen, Chuanwu; Duan, Yongping; Zhou, Lijuan; Vahling, Cheryl M

2011-01-01

291

Characterization of management and environmental factors associated with regional variations in potato zebra chip occurrence.  

Science.gov (United States)

Potato zebra chip (ZC), caused by the bacterial pathogen 'Candidatus Liberibacter solanacearum', which is vectored by the potato psyllid (Bactericera cockerelli), has caused widespread damage to U.S. potato production ever since its first discovery in south Texas in 2000. To determine the influence of environmental factors and management practices on ZC occurrence, data on management and meteorological variables, field locations, and psyllid counts were collected over a 3-year period (2010 to 2012) from six locations across the central United States (south Texas to Nebraska). At these locations, ZC-symptomatic plants were counted in 26 fields from systematically established 20 m × 30 m plots around the field edges and field interiors. Mean numbers of symptomatic plants per plot were classified into two intensity classes (ZC ? 3 or ZC > 3) and subjected to discriminant function and logistic regression analyses to determine which factors best distinguish between the two ZC intensity classes. Of all the variables, location, planting date, and maximum temperature were found to be the most important in distinguishing between ZC intensity classes. These variables correctly classified 88.5% of the fields into either of the two ZC-intensity classes. Logistic regression analysis of the individual variables showed that location accounted for 90% of the variations, followed by planting date (86%) and maximum temperature (70%). There was a low but significant (r = -0.44983, P = 0.0211) negative correlation between counts of psyllids testing positive for pathogen and latitudinal locations, indicating a south-to-north declining trend in counts of psyllids testing positive for the pathogen. A similar declining trend also was observed in ZC occurrence (r = -0.499, P = 0.0094). PMID:23883154

Workneh, F; Henne, D C; Goolsby, J A; Crosslin, J M; Whipple, S D; Bradshaw, J D; Rashed, A; Paetzold, L; Harveson, R M; Rush, C M

2013-12-01

292

Cloning, Expression and Characterization of Zebra Fish Ferroportin in Hek 293T Cell Line  

Directory of Open Access Journals (Sweden)

Full Text Available Background: Ferroportin (Fpn, a regulator of iron homeostasis is a conserved membrane protein that exports iron across the enterocytes, macrophages and hepatocytes into the blood circulation. Fpn has also critical influence on survival of microorganisms whose growth is dependent upon iron, thus preparation of Fpn is needed to study the role of iron in immunity and pathogenesis of micoorganisms.Methods: To prepare and characterize a recombinant ferroportin, total RNA was extracted from Indian zebrafish duodenum, and used to synthesize cDNA by RT-PCR. PCR product was first cloned in Topo TA vector and then subcloned into the GFP expression vector pEGFP-N1. The final resulted plasmid (pEGFP-ZFpn was used for expression of Fpn-EGFP protein in Hek 293T cells.Results: The expression was confirmed by appearance of fluorescence in Hek 293 T cells. Recombinant Fpn was further characterized by submission of its predicted amino acid sequences to the TMHMM V2.0 prediction server (hidden Markov model, NetOGlyc 3.1 and NetNGlyc 3.1 servers. The obtained Fpn from indian zebrafish also contained eight transmembrane domains with N- and C-termini inside the cytoplasm and harboured 78 O-glycosylated amino acids.Conclusion: The recombinant Fpn from Indian zebra fish was successfully expressed in Hek 293 cell line. Although the discrepancy in two amino acids was observed in our produced Fpn and resulted in an additional O-glycosylation site, but had no effect on the topology of the protein compared to other Fpn described by other researchers. Therefore this construct can be used in future iron studies.

A Memarnejadian

2012-01-01

293

Effects of acute corticosterone treatment on partner preferences in male and female zebra finches (Taeniopygia guttata).  

Science.gov (United States)

Stress alters physiology and behavior across species. Most research on the effects of stress on behavior uses chronic stressors, and most are correlational. The effects of acute stressors on physiology and behavior have been mixed. Here, we use zebra finches, a highly gregarious species that forms long-term pair bonds, to test the effects of an acute corticosterone (CORT) on opposite-sex partner preferences over a same-sex individual or a group (the latter is a highly appealing option). We had two competing hypotheses. First, we predicted that acute CORT would alter preferences for the opposite sex bird in both conditions in both sexes. However, since there is a sex difference in the effects of CORT on partner preferences in voles, these effects may be more pronounced in males than in females. To test our hypotheses, we administered 2 doses of CORT (10?g and 20?g) or vehicle (control) using a repeated measures design. In the male vs. female test, there was a significant Sex by Treatment interaction, such that in males, 10?g CORT increased preferences for a female over the male compared to when these same males were treated with saline at baseline. There were no effects of treatment in females. In the opposite-sex vs. group condition, there was an overall effect of Treatment, such that the 10?g dose increased preference for the opposite-sex individual over both saline treatments, regardless of sex. These findings further our understanding of the effects of an acute stressor on sexual partner preferences. PMID:24530631

LaPlante, Kimberly A; Huremovic, Enida; Tomaszycki, Michelle L

2014-04-01

294

De novo establishment of wild-type song culture in the zebra finch.  

Science.gov (United States)

Culture is typically viewed as consisting of traits inherited epigenetically, through social learning. However, cultural diversity has species-typical constraints, presumably of genetic origin. A celebrated, if contentious, example is whether a universal grammar constrains syntactic diversity in human languages. Oscine songbirds exhibit song learning and provide biologically tractable models of culture: members of a species show individual variation in song and geographically separated groups have local song dialects. Different species exhibit distinct song cultures, suggestive of genetic constraints. Without such constraints, innovations and copying errors should cause unbounded variation over multiple generations or geographical distance, contrary to observations. Here we report an experiment designed to determine whether wild-type song culture might emerge over multiple generations in an isolated colony founded by isolates, and, if so, how this might happen and what type of social environment is required. Zebra finch isolates, unexposed to singing males during development, produce song with characteristics that differ from the wild-type song found in laboratory or natural colonies. In tutoring lineages starting from isolate founders, we quantified alterations in song across tutoring generations in two social environments: tutor-pupil pairs in sound-isolated chambers and an isolated semi-natural colony. In both settings, juveniles imitated the isolate tutors but changed certain characteristics of the songs. These alterations accumulated over learning generations. Consequently, songs evolved towards the wild-type in three to four generations. Thus, species-typical song culture can appear de novo. Our study has parallels with language change and evolution. In analogy to models in quantitative genetics, we model song culture as a multigenerational phenotype partly encoded genetically in an isolate founding population, influenced by environmental variables and taking multiple generations to emerge. PMID:19412161

Fehér, Olga; Wang, Haibin; Saar, Sigal; Mitra, Partha P; Tchernichovski, Ofer

2009-05-28

295

Effects of lethal and sublethal concentrations of the herbicide, triclopyr butoxyethyl ester, in the diet of zebra finches.  

Science.gov (United States)

Lethal and sublethal effects of dietary triclopyr butoxyethyl ester (TBEE) on zebra finches (Poephila guttata Gould) were determined in laboratory experiments conducted between 8 January and 1 May 1991. The 8-day median lethal dietary concentration, LC50 (95% confidence interval), of TBEE to zebra finches was 1,923 (1,627 to 2,277) mg/kg. In the sublethal effects experiment, when birds were exposed to 500 mg/kg TBEE in the diet for 29 days, food consumption and body weight were significantly depressed (P 0.05). Perch-hopping activity was depressed relative to controls in the 500 mg/kg group, and elevated in the 150 mg/kg group, but neither of these differences was significantly (P > 0.05). Disappearance of TBEE residues from treated seeds over the 29 day experimental period followed an exponential decay model, with half-lives in the order of 15 to 18 days. On the basis of our observation that TBEE had no significant adverse effects at a concentration greater than the maximum expected environmental concentration, we propose that forestry applications of triclopyr at registered dosage rates pose little risk to wild songbirds. PMID:7933272

Holmes, S B; Thompson, D G; Wainio-Keizer, K L; Capell, S S; Staznik, B

1994-07-01

296

Separating natural from anthropogenic causes of impairment in Zebra mussel (Dreissena polymorpha) populations living across a pollution gradient.  

Science.gov (United States)

The relationship between the reproductive stage, the total lipid content and eight broadly used biochemical stress responses were used to assess seasonal and pollutant effects across eleven different zebra mussel (Dreissena polymorpha) populations from the Ebro and Mijares river basin, Spain. Biochemical markers included superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), glutathione S transferase (GST), multixenobiotic transporter activity (MXR), lactate dehydrogenase (LDH), lipid peroxidation (LPO) and single strand DNA breaks. Principal component analyses of zebra mussel responses across an annual cycle, showed a marked gonad stage component in total lipid content and biochemical responses. The same response pattern was observed across the populations sampled along a broad geographical and pollution gradient. Population differences on the gonad developmental stage were highly correlated with most of the measured responses and unrelated with the pollution gradient. Conversely, bioaccumulation of organic and inorganic contaminant residues was more related to pollution sources than with the reproductive cycle. These results indicate that the reproductive cycle is the major factor affecting the temporal and spatial variation of the studied markers in D. polymorpha. PMID:24742819

Faria, Melissa; Ochoa, Victoria; Blázquez, Mercedes; Juan, Maria Fernandes San; Lazzara, Raimondo; Lacorte, Silvia; Soares, Amadeu M V M; Barata, Carlos

2014-07-01

297

Spectral and spatial observations of microwave spikes and zebra structure in the short radio burst of May 29, 2003  

CERN Document Server

The unusual radio burst of May 29, 2003 connected with the M1.5 flare in AR 10368 has been analyzed. It was observed by the Solar Broadband Radio Spectrometer (SBRS/Huairou station, Beijing) in the 5.2-7.6 GHz range. It proved to be only the third case of a neat zebra structure appearing among all observations at such high frequencies. Despite the short duration of the burst (25 s), it provided a wealth of data for studying the superfine structure with millisecond resolution (5 ms). We localize the site of emission sources in the flare region, estimate plasma parameters in the generation sites, and suggest applicable mechanisms for interpretating spikes and zebra-structure generation. Positions of radio bursts were obtained by the Siberian Solar Radio Telescope (SSRT) (5.7 GHz) and Nobeyama radioheliograph (NoRH) (17 GHz). The sources in intensity gravitated to tops of short loops at 17 GHz, and to long loops at 5.7 GHz. Short pulses at 17 GHz (with a temporal resolution of 100 ms) are registered in the R-pol...

Chernov, G P; Meshalkina, N S; Yan, Y; Tan, C

2011-01-01

298

Acoustic Communication and Sound Degradation: How Do the Individual Signatures of Male and Female Zebra Finch Calls Transmit over Distance?  

Science.gov (United States)

Background Assessing the active space of the various types of information encoded by songbirds' vocalizations is important to address questions related to species ecology (e.g. spacing of individuals), as well as social behavior (e.g. territorial and/or mating strategies). Up to now, most of the previous studies have investigated the degradation of species-specific related information (species identity), and there is a gap of knowledge of how finer-grained information (e.g. individual identity) can transmit through the environment. Here we studied how the individual signature coded in the zebra finch long distance contact call degrades with propagation. Methodology We performed sound transmission experiments of zebra finches' distance calls at various propagation distances. The propagated calls were analyzed using discriminant function analyses on a set of analytical parameters describing separately the spectral and temporal envelopes, as well as on a complete spectrographic representation of the signals. Results/Conclusion We found that individual signature is remarkably resistant to propagation as caller identity can be recovered even at distances greater than a hundred meters. Male calls show stronger discriminability at long distances than female calls, and this difference can be explained by the more pronounced frequency modulation found in their calls. In both sexes, individual information is carried redundantly using multiple acoustical features. Interestingly, features providing the highest discrimination at short distances are not the same ones that provide the highest discrimination at long distances. PMID:25061795

Mouterde, Solveig C.; Theunissen, Frédéric E.; Elie, Julie E.; Vignal, Clémentine; Mathevon, Nicolas

2014-01-01

299

The formation and maintenance of social relationships increases nonapeptide mRNA in zebra finches of both sexes.  

Science.gov (United States)

The nonapeptides oxytocin and vasopressin are believed to be involved in affiliation across species, but converging evidence is lacking. In monogamous zebra finches, oxytocin antagonists decrease pairing. The goal of the present study was to test if this relationship is bidirectional. We predicted that pairing would increase mesotocin (MT) and vasotocin (VT) mRNA (avian homologues of oxytocin and vasopressin) at nonapeptide neurosecretory sites: the paraventrivular nucleus (PVN) of the hypothalamus, which contains both MT and VT, and the bed nucleus of the stria terminalis (BSTm), which contains VT. To test our hypotheses, zebra finches of both sexes paired for 48 hr or 2 weeks in a naturalistic choice paradigm. Birds that did not pair or were not given the opportunity to pair were included as control groups. Pairing increased VT and MT mRNA in the PVN compared to both control groups. In the BSTm, animals paired for 48 hr had more cells expressing VT mRNA than did animals not given the opportunity to pair, and males had higher VT mRNA than did females. In males, singing primarily explained variations in MT mRNA, as well as VT mRNA in both the PVN and BSTm. In females, pairing behaviors explained variations in MT, but did not explain variations in VT in either brain region. Our results provide evidence that the relationship between nonapeptides and pairing are bidirectional and may be sexually differentiated. PMID:24512066

Lowrey, Erin Marie; Tomaszycki, Michelle Lynn

2014-02-01

300

Is the Rate of Metabolic Ageing and Survival Determined by Basal Metabolic Rate in the Zebra Finch?  

Science.gov (United States)

The relationship between energy metabolism and ageing is of great interest because aerobic metabolism is the primary source of reactive oxygen species which is believed to be of major importance in the ageing process. We conducted a longitudinal study on captive zebra finches where we tested the effect of age on basal metabolic rate (BMR), as well as the effect of BMR on the rate of metabolic ageing (decline in BMR with age) and survival. Basal metabolic rate declined with age in both sexes after controlling for the effect of body mass, indicating a loss of functionality with age. This loss of functionality could be due to accumulated oxidative damage, believed to increase with increasing metabolic rate, c.f. the free radical theory of ageing. If so, we would expect the rate of metabolic ageing to increase and survival to decrease with increasing BMR. However, we found no effect of BMR on the rate of metabolic ageing. Furthermore, survival was not affected by BMR in the males. In female zebra finches there was a tendency for survival to decrease with increasing BMR, but the effect did not reach significance (Pzebra finches. PMID:25265184

Rønning, Bernt; Moe, Børge; Berntsen, Henrik H.; Noreen, Elin; Bech, Claus

2014-01-01

301

Sex-biased investment in yolk androgens depends on female quality and laying order in zebra finches (Taeniopygia guttata)  

Science.gov (United States)

The Trivers-Willard hypothesis predicts sex biases in parental investment according to parental condition. In addition, parents may need to sex bias their investment if there is an asymmetry between the sexes in offspring fitness under different conditions. For studying maternal differential investment, egg resources are ideal subjects because they are self contained and allocated unequivocally by the female. Recent studies show that yolk androgens can be beneficial to offspring, so here we test for sex-biased investment with maternal investment of yolk testosterone (T) in zebra finch (Taeniopygia guttata) eggs. From the Trivers-Willard hypothesis, we predicted females to invest more in male eggs in optimum circumstances (e.g. good-condition mother, early-laid egg), and more in female eggs under suboptimal conditions (e.g. poor-condition mother, late-laid egg). This latter prediction is also because in this species there is a female nestling disadvantage in poor conditions and we expected mothers to help compensate for this in female eggs. Indeed, we found more yolk T in female than male eggs. Moreover, in accordance with our predictions, yolk T in male eggs increased with maternal quality relative to female eggs, and decreased with laying order relative to female eggs. This supports our predictions for the different needs and value of male and female offspring in zebra finches. Our results support the idea that females may use yolk androgens as a tool to adaptively manipulate the inequalities between different nestlings.

Gilbert, Lucy; Rutstein, Alison N.; Hazon, Neil; Graves, Jefferson A.

2005-04-01

302

Measurements and calculations of ratios of effective fission cross-sections in the zero-power fast reactor, Zebra  

International Nuclear Information System (INIS)

The comparison of measured and calculated central fission ratios provides a useful method for checking the accuracy of calculated spectra and fission cross-section data. A set of parallel plate fission chambers was specially made for Zebra. The design was based on that of Kirn's chambers used by the ZPR-III group at ANL, Idaho, and incorporated a number of improvements. In particular, the wall thickness was reduced to reduce the degradation of the spectrum. The fissile coatings in the earlier chambers were prepared by a painting technique and those in the later chambers by an electrodeposition method. The mass deposited was determined by low geometry or assay. The construction of the chambers and the method of calibration and use are described. Central fission ratios in six Zebra cores measured to an accuracy of 1-3% are compared with values computed using the FD2 data set and the CRAM or SCRAMBLE multigroup diffusion theory programmes. This comparison suggests that the calculations give too few neutrons at high energies. There is also evidence that some of the fission cross-section data used in the FD2 set is in error. (author)

303

Evaluation of Octhylphenol Effect on Development and Survival on Zebra Fish (Danio Rerio During Different Ontogenic Period  

Directory of Open Access Journals (Sweden)

Full Text Available This paper is part of a complex study of our research collective that studies the toxic effect of the ethinylestradiolum, and some of the polyethoxylated alkylphenols on the growth and reproduction of the Zebra fish (Danio rerio and of the common Carp (Cyprinus carpio. Our study aim was to evaluate the effect of octylphenol on growth and survival of zebra fish, from 21-115 days, and within 21-75 days of life. For this purpose, for each period under study, fishes were divided into three groups of 30 individuals, named: Lot 1 - Control, respectively lots 2 and 3, at which the administrated octylphenol concentrations were of 60 ?g L-1, respectively 100 ?g L-1. Fishes of the six groups were raised in 30-liters aquariums (30 fish / aquarium. The growth was measured by weighing and biometric measurements (total length, standard length, the length of the head, maximal height, minimal height and the mass of the body, while the surviving rate was established at the end of every period and at the end of the experiment, when we were able to calculate the total number of dead fish. Biometric study of the analysis performed in 75 days, 115 days respectively shows that octylphenol has negative influence on body development, and survival both, the highest percentage of mortality (46,66% was registered at 100 ?gL-1 concentration, between 21 -75 days.

Gabi Dumitrescu

2010-05-01

304

Mutations of amino acids in the DNA-recognition domain of Epstein-Barr virus ZEBRA protein alter its sub-nuclear localization and affect formation of replication compartments  

International Nuclear Information System (INIS)

ZEBRA, a transcription factor and DNA replication protein encoded by the Epstein-Barr virus (EBV) BZLF1 gene, plays indispensable roles in the EBV lytic cycle. We recently described the phenotypes of 46 single amino acid substitutions introduced into the DNA-recognition region of ZEBRA [Heston, L., El-Guindy, A., Countryman, J., Dela Cruz, C., Delecluse, H.J., and Miller, G. 2006]. The 27 DNA-binding-proficient mutants exhibited distinct defects in their ability to activate expression of the kinetic classes of viral genes. Four phenotypic variants could be discerned: wild-type, defective at activating Rta, defective at activating early genes, and defective at activating late genes. Here we analyze the distribution of ZEBRA within the nucleus and the localization of EA-D (the viral DNA polymerase processivity factor), an indicator of the development of replication compartments, in representatives of each phenotypic group. Plasmids encoding wild-type (WT) and mutant ZEBRA were transfected into 293 cells containing EBV-bacmids. WT ZEBRA protein was diffusely and smoothly distributed throughout the nucleus, sparing nucleoli, and partially recruited to globular replication compartments. EA-D induced by WT ZEBRA was present diffusely in some cells and concentrated in globular replication compartments in other cells. The distribution of ZEBRA and EA-D proteins was identical to WT following transfection of K188R, a mutant with a conservative change. The distribution of S186A rvative change. The distribution of S186A mutant ZEBRA protein, defective for activation of Rta and EA-D, was identical to WT, except that the mutant ZEBRA was never found in globular compartments. Co-expression of Rta with S186A mutant rescued diffuse EA-D but not globular replication compartments. The most striking observation was that several mutant ZEBRA proteins defective in activating EA-D (R179A, K181A and A185V) and defective in activating lytic viral DNA replication and late genes (Y180E and K188A) were localized to numerous punctate foci. The speckled appearance of R179A and Y180E was more regular and clearly defined in EBV-positive than in EBV-negative 293 cells. The Y180E late-mutant induced EA-D, but prevented EA-D from localizing to globular replication compartments. These results show that individual amino acids within the basic domain influence localization of the ZEBRA protein and its capacity to induce EA-D to become located in mature viral replication compartments. Furthermore, these mutant ZEBRA proteins delineate several stages in the processes of nuclear re-organization which accompany lytic EBV replication

305

Entomopathogenic fungi (Hypocreales) for control of potato psyllid, Bactericerta cockerelli (Sulc)(Hemiptera: Triozidae) in an area endemic for zebra chip disease of potato  

Science.gov (United States)

Potato psyllid, Bactericera cockerelli (Šulc), is a serious pest of potato, tomato and other solanaceous vegetables in the United States, Mexico, Central America, and New Zealand and is responsible for transmission of Candidatus Liberibacter solanacearum causing a disease known as “zebra chip” (ZC)....

306

Developmental exposure to a brominated flame retardant: An assessment of effects on physiology, growth, and reproduction in a songbird, the zebra finch  

International Nuclear Information System (INIS)

Mixtures of polybrominated diphenyl ethers (PBDEs) have been widely used as additive flame retardants, and BDE-99 is one of the most predominant congeners found in the environment. BDE-99 has been reported in avian samples worldwide, yet knowledge of its toxicity to birds is minimal. We assessed the short- and long-term effects of nestling exposure to environmentally relevant levels of BDE-99 in a model passerine, the zebra finch. Early exposure to BDE-99 did not affect hematocrit, oxidative stress, or thyroid hormones in either the juvenile or adult stages, and there were no effects on chick growth or survival. BDE-99 exposure caused a dose-dependent delay in timing of reproduction, but there were no other effects on reproductive success. In zebra finches, endpoints related to reproductive behavior appear to be the most sensitive to BDE-99. However, passerines overall appear to be less sensitive than birds of prey or mammals to PBDE exposure. -- Highlights: •We exposed zebra finches nestlings to BDE-99 and raised them to sexual maturity. •Found no effects on physiology, chick growth, survival, or reproductive success. •As BDE-99 dose increased, laying interval increased. •Passerine birds possibly less sensitive to BDE-99 than mammals or other bird species. -- Nestling exposure to BDE-99 affects timing of breeding in zebra finches, but overall passerines appear to be less sensitive to PBDEs than mammals or other bird species

307

Simple sequence repeats in zebra finch (Taeniopygia guttata) expressed sequence tags: a new resource for evolutionary genetic studies of passerines  

OpenAIRE

Abstract Background Passerines (perching birds) are widely studied across many biological disciplines including ecology, population biology, neurobiology, behavioural ecology and evolutionary biology. However, understanding the molecular basis of relevant traits is hampered by the paucity of passerine genomics tools. Efforts to address this problem are underway, and the zebra finch (Taeniopygia guttata) will be the first passerine to have its genome sequenced. Here w...

Birkhead Timothy R; Hale Matthew C; Slate Jon

2007-01-01

308

Spatio-temporal spawning and larval dynamics of a zebra mussel (Dreissena polymorpha) population in a North Texas Reservoir: implications for invasions in the southern United States  

Science.gov (United States)

Zebra mussels were first observed in Texas in 2009 in a reservoir (Lake Texoma) on the Texas-Oklahoma border. In 2012, an established population was found in a near-by reservoir, Ray Roberts Lake, and in June 2013, settled mussels were detected in a third north Texas reservoir, Lake Lewisville. An established population was detected in Belton Lake in September 2013. With the exception of Louisiana, these occurrences in Texas mark the current southern extent of the range of this species in the United States. Previous studies indicate that zebra mussel populations could be affected by environmental conditions, especially increased temperatures and extreme droughts, which are characteristic of surface waters of the southern and southwestern United States. Data collected during the first three years (2010–12) of a long-term monitoring program were analyzed to determine if spatio-temporal zebra mussel spawning and larval dynamics were related to physicochemical water properties in Lake Texoma. Reproductive output of the local population was significantly related to water temperature and lake elevation. Estimated mean date of first spawn in Lake Texoma was approximately 1.5 months earlier and peak veliger densities were observed two months earlier than in Lake Erie. Annual maximum veliger density declined significantly during the study period (p zebra mussels along the current southern frontier of their geographic range. Although the future population size trajectory and geographic range are uncertain, increased temperatures and intermittent, extreme droughts likely will affect spatio-temporal dynamics of established populations if zebra mussels spread farther into the southern and southwestern United States.

Churchill, Christopher John

2013-01-01

309

Epi-genetics modifications induced by a depleted uranium exposure in the zebra fish  

Energy Technology Data Exchange (ETDEWEB)

The work presented here integrates in the general framework of assessment of effects of chronic exposure to low doses of radionuclides. This evaluation necessarily involves the study of the mechanisms of toxic action at the cellular or subcellular level, in order to better understand the processes of propagation of effects to the level of the populations or ecosystems. As such, the question of the mechanisms underlying the trans-generational effects and the adaptive capacity of organisms is central, both in humans and in animal species. Epigenetic refer to changes in gene function that do not involve changes in DNA sequence, and which are transmitted in a hereditary manner by mitosis or meiosis. The latter plays a key role in these trans-generational effects. Among these changes, DNA-methylation is one of the most studied epigenetic parameters. This work is part of a PhD, included in the European COMET project (Euratom 7. Framework Program), and focuses on epigenetic modifications induced in zebra fish after a chronic exposure to radionuclides. Male and female fishes were exposed to 2 and 20 ?g.L{sup -1} of depleted uranium for 24 days. After 7 and 24 days of exposure, brain, gonads, and eyes were collected in order to study changes in DNA methylation. In addition, genotoxicity was measured by the ?H2AX assay. The overall changes in DNA methylation were studied by AFLP-MS and HPLC-MS, in order to know if the exposure to depleted uranium changes the global status of DNA methylation. We have found a decrease in the global level of methylation in the eyes of males after 24 days of exposure, the diminution being much more important and significant at the higher concentration of exposure (11.79 ± 3.62 against 52.43 ± 3.01 for controls) This study will be refined by analyzing the methylation of specific regions of the genome, because it represent the sequences of genes involved in major physiological functions and that may be subject to variations in the methylation of the region regulating their expression. Thus, we will be able to identify target genes undergoing epigenetic changes, and linking these findings to a possible alteration of the physiological functions encoded. After this first experiment, we will have more information on the epigenetic impacts and targets of these changes following exposure to depleted uranium. Exposure of organisms to an external gamma radiation will be then performed to compare the methylation status of target genes. Document available in abstract form only. (authors)

Gombeau, K.; Pereira, S.; Adam-Guillermin, C. [IRSN/PRP-ENV/SERIS/LECO (France); Bourdineaud, J.P. [UMR CNRS 5805 EPOC (France); Ravanat, J.L. [INAC/Scib UMR E3 CEA-UJF (France)

2014-07-01

310

Epi-genetics modifications induced by a depleted uranium exposure in the zebra fish  

International Nuclear Information System (INIS)

The work presented here integrates in the general framework of assessment of effects of chronic exposure to low doses of radionuclides. This evaluation necessarily involves the study of the mechanisms of toxic action at the cellular or subcellular level, in order to better understand the processes of propagation of effects to the level of the populations or ecosystems. As such, the question of the mechanisms underlying the trans-generational effects and the adaptive capacity of organisms is central, both in humans and in animal species. Epigenetic refer to changes in gene function that do not involve changes in DNA sequence, and which are transmitted in a hereditary manner by mitosis or meiosis. The latter plays a key role in these trans-generational effects. Among these changes, DNA-methylation is one of the most studied epigenetic parameters. This work is part of a PhD, included in the European COMET project (Euratom 7. Framework Program), and focuses on epigenetic modifications induced in zebra fish after a chronic exposure to radionuclides. Male and female fishes were exposed to 2 and 20 ?g.L-1 of depleted uranium for 24 days. After 7 and 24 days of exposure, brain, gonads, and eyes were collected in order to study changes in DNA methylation. In addition, genotoxicity was measured by the ?H2AX assay. The overall changes in DNA methylation were studied by AFLP-MS and HPLC-MS, in order to know if the exposure to depleted uranium changes the global status of DNA methylation. We have found a decrease in the global level of methylation in the eyes of males after 24 days of exposure, the diminution being much more important and significant at the higher concentration of exposure (11.79 ± 3.62 against 52.43 ± 3.01 for controls) This study will be refined by analyzing the methylation of specific regions of the genome, because it represent the sequences of genes involved in major physiological functions and that may be subject to variations in the methylation of the region regulating their expression. Thus, we will be able to identify target genes undergoing epigenetic changes, and linking these findings to a possible alteration of the physiological functions encoded. After this first experiment, we will have more information on the epigenetic impacts and targets of these changes following exposure to depleted uranium. Exposure of organisms to an external gamma radiation will be then performed to compare the methylation status of target genes. Document available in abstract form only. (authors)

311

Epstein-Barr virus-encoded EBNA1 and ZEBRA: targets for therapeutic strategies against EBV-carrying cancers.  

Science.gov (United States)

The EBV-encoded EBNA1 was first discovered 40 years ago, approximately 10 years after the presence of EBV had been demonstrated in Burkitt's lymphoma cells. It took another 10 years before the functions of EBNA1 in maintaining the viral genome were revealed, and it has since been shown to be an essential viral factor expressed in all EBV-carrying cells. Apart from serving to maintain the viral episome and to control viral replication and gene expression, EBNA1 also harbours a cis-acting mechanism that allows virus-carrying host cells to evade the immune system. This relates to a particular glycine-alanine repeat (GAr) within EBNA1 that has the capacity to suppress antigen presentation to the major histocompatibility complex (MHC) class I pathway. We discuss the role of the GAr sequence at the level of mRNA translation initiation, rather than at the protein level, as at least part of the mechanism to avoid MHC presentation. Interfering with this mechanism has become the focus of the development of immune-based therapies against EBV-carrying cancers, and some lead compounds that affect translation of GAr-carrying mRNAs have been identified. In addition, we describe the EBV-encoded ZEBRA factor and the switch from the latent to the lytic cycle as an alternative virus-specific target for treating EBV-carrying cancers. Understanding the molecular mechanisms of how EBNA1 and ZEBRA interfere with cellular pathways not only opens new therapeutic approaches but continues to reveal new cell-biological insights on the interplay between host and virus. This review is a tale of discoveries relating to how EBNA1 and ZEBRA have emerged as targets for specific cancer therapies against EBV-carrying diseases, and serves as an illustration of how mRNA translation can play roles in future immune-based strategies to target viral disease. Copyright © 2014 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. PMID:25186125

Daskalogianni, Chrysoula; Pyndiah, Slovénie; Apcher, Sébastien; Mazars, Anne; Manoury, Bénédicte; Ammari, Nisrine; Nylander, Karin; Voisset, Cécile; Blondel, Marc; Fåhraeus, Robin

2015-01-01

312

Does zebra mussel (Dreissena polymorpha) represent the freshwater counterpart of Mytilus in ecotoxicological studies? A critical review.  

Science.gov (United States)

One of the fundamentals in the ecotoxicological studies is the need of data comparison, which can be easily reached with the help of a standardized biological model. In this context, any biological model has been still proposed for the biomonitoring and risk evaluation of freshwaters until now. The aim of this review is to illustrate the ecotoxicological studies carried out with the zebra mussel Dreissena polymorpha in order to suggest this bivalve species as possible reference organism for inland waters. In detail, we showed its application in biomonitoring, as well as for the evaluation of adverse effects induced by several pollutants, using both in vitro and in vivo experiments. We discussed the advantages by the use of D. polymorpha for ecotoxicological studies, but also the possible limitations due to its invasive nature. PMID:25463737

Binelli, A; Della Torre, C; Magni, S; Parolini, M

2014-11-17

313

Analysis of results of recent implosions of palladium wire loads arranged in single planar wire arrays on Zebra at UNR  

Science.gov (United States)

Experiments with palladium wire loads were performed on Zebra at UNR to understand the implosion and radiative properties of this unique wire material. The loads were planar wire arrays (PWA) arranged in a single row for a uniform load with twelve palladium 10 ?m wires (total mass M ˜ 227 ?g) and a combined load with five palladium 25 ?m wires and one aluminum 40 ?m wire (M˜656 ?g). A full diagnostic set which included more than ten different beam-lines was implemented. The implosion of these Pd loads produced a high radiation yield (27 kJ for a heavier load) which is comparable to recently tested Ag PWA loads. The main focus was put on comparison of implosion and radiative characteristics of these two shots and with results for the identical Ag PWA load. Future experiments with modified palladium wires and their applications are discussed.

Covington, A. M.; Darling, T.; Safranova, A. S.; Kantsyrev, V. L.; Esaulov, A. A.; Shrestha, I.; Williamson, K. M.; Keim, S.; Shylaptseva, V.; Osborne, G. C.; Weller, M. E.; Ouart, N. D.

2010-11-01

314

X-ray pulse shaping in experiments with planar wire arrays at the 1.6 MA Zebra generator  

Energy Technology Data Exchange (ETDEWEB)

The shaping of the x-ray radiation pulse is very important in both radiation physics research and Inertial Confinement Fusion studies. The novel planar wire array (PWA) was found to be the effective radiator tested at the university-scale 1.6 MA, 100 ns Zebra generator. The single PWA consists of a single row of wires that are parallel to each other, while the double planar wire array (DPWA) and triple planar wire array (TPWA) include two or three parallel plane wire rows, respectively. All multi-planar geometries resulted in a cascade-type array implosion with a complicated multi-step precursor formation before plasma stagnation. The PWAs (without additional core foam target) feature a dynamic precursor evolution that is a powerful tool for x-ray pulse shaping. The shape and timing of the x-ray pulse from different PWAs were theoretically predicted and experimentally analyzed for a variety of planar wire arrays.

Kantsyrev, V L; Safronova, A S; Esaulov, A A; Williamson, K M; Shrestha, I; Osborne, G C; Weller, M E; Yilmaz, M F; Ouart, N D; Shlyaptseva, V V [Physics Department, University of Nevada, Reno NV 89557 (United States); Velikovich, A L [Naval Research Laboratory, Washington, DC 20375 (United States); Rudakov, L I, E-mail: victor@physics.unr.ed [Icarus Research Inc., Bethesda, MD 20824 (United States)

2010-08-01

315

A description of the equipment for time-of-flight spectrum measurements on the fast reactor ZEBRA  

International Nuclear Information System (INIS)

The pulsed source for the time-of-flight equipment consists of 14 MeV S-band linear electron accelerator, drift tube and water-cooled uranium-molybdenum alloy target installed on the ZEBRA lattice. Neutrons are extracted via a probe tube inserted into the core and an evacuated flight tube with counting stations at 50 m, 97 m and 200 m from the core centre. Two types of neutron detector are described and also the Perranti Argus 500 on-line computer which is used for data collection. The equipment is used for measuring the neutron energy spectra from the lowest energies up to about 1 MeV. (author)

316

Cellular energy allocation in zebra mussels exposed along a pollution gradient: linking cellular effects to higher levels of biological organization  

International Nuclear Information System (INIS)

Organisms exposed to suboptimal environments incur a cost of dealing with stress in terms of metabolic resources. The total amount of energy available for maintenance, growth and reproduction, based on the biochemical analysis of the energy budget, may provide a sensitive measure of stress in an organism. While the concept is clear, linking cellular or biochemical responses to the individual and population or community level remains difficult. The aim of this study was to validate, under field conditions, using cellular energy budgets [i.e. changes in glycogen-, lipid- and protein-content and mitochondrial electron transport system (ETS)] as an ecologically relevant measurement of stress by comparing these responses to physiological and organismal endpoints. Therefore, a 28-day in situ bioassay with zebra mussels (Dreissena polymorpha) was performed in an effluent-dominated stream. Five locations were selected along the pollution gradient and compared with a nearby (reference) site. Cellular Energy Allocation (CEA) served as a biomarker of cellular energetics, while Scope for Growth (SFG) indicated effects on a physiological level and Tissue Condition Index and wet tissue weight/dry tissue weight ratio were used as endpoints of organismal effects. Results indicated that energy budgets at a cellular level of biological organization provided the fastest and most sensitive response and energy budgets are a relevant currency to extrapolate cellular effects to higher leveltrapolate cellular effects to higher levels of biological organization within the exposed mussels. - Exposure of zebra mussels along a pollution gradient has adverse effects on the cellular energy allocation, and results can be linked with higher levels of biological organization

317

Metabolic programming of zebra fish Danio rerio uncovered. Physiological performance as explained by dynamic energy budget theory and life-cycle consequence of uranium induced perturbations  

International Nuclear Information System (INIS)

The aim of this dissertation is to characterize the toxicity of uranium on the metabolism of zebra fish, nio rerio. The first three chapters of this manuscript are dedicated to characterizing the blank metabolism of zebra fish. I used the Dynamic Energy Budget (deb) theory for this characterisation; it is presently the only theory that covers the full life cycle of the organism and quantifies feeding, assimilation, growth, reproduction, maturation, maintenance and ageing. Any metabolic effect of uranium should appear as effects on one or more of these fundamental processes. Since the life span of zebra fish is some four and a half years, and larger individuals respond slower to chemical stress, the focus was on the early life stages. Considerable breakthroughs in the quantification of zebra fish development, growth and reproduction have been made. It turned out the zebra fish accelerates its metabolism after birth till metamorphosis, when acceleration ceases. This process is seen in some, but not all, species of fish. Another striking conclusion was that somatic maintenance was much higher than is typical for fish. We don't yet have an explanation for this funding. Further it turned out that the details of reproduction matter: allocation to reproduction (in adults) accumulates in a reproduction buffer and this buffer is used to prepare batches of eggs. We needed to detail this preparation process to understand how zebra fish can eliminate uranium via eggs. Deb theory specifies that a particular developmental stage (birth, metamorphosis, puberty) is reached at specified levels of maturity. For different temperatures and food levels, that can occur at different ages and body sizes. We extended this idea to include all the described morphologically defined developmental stages of the zebra fish in the literature; the observed variations in ages and body sizes can now be explained by deb theory. To test if deb theory can also explain perturbations of maturation, we studied developmental patterns in two types of taxonomically related frog species of similar body size. One type shows a typical developmental pattern as embryo, feeding tadpole and juvenile frog. The other type shows, after hatching, but before birth (= start of feeding) a significant acceleration of maturation, which is visible as an increased respiration and retarded growth, with big effects on size at a given developmental stage. This acceleration is reduced after metamorphosis but compared to the standard type of frog, it takes considerable time to catch up in growth. All these changes could be captured accurately with deb theory by a temporary change in a single parameter: the fraction of mobilised reserve that is allocated to somatic maintenance plus growth, as opposed to maturity maintenance plus maturation. The conclusion is that the observed perturbations of maturation and the age and size variations at various developmental stages provide strong support for how deb theory incorporates maturation. We not only required detail on maturation but also on starvation, especially in the early juvenile stages. The problem is that, according to deb theory, maintenance is paid from mobilised reserve, but when food is scarce or absent, reserve becomes depleted and maintenance can no longer be paid from mobilised reserve. We included more detail on what happens exactly under such conditions. More specifically we modelled the processes of rejuvenation and shrinking (of structure) and their consequence for hazard rate. We managed to capture observed size and survival trajectories of fish fry under controlled starving conditions. These processes are not only important to capture effects of uranium on feeding, but have a much wider ecological significance in field situations. As a result of my work, there is now a formal basis for understanding (and predicting) how the physiological performance of zebra fish relates to food intake. The model was used to detect uranium induced eco-physiological deviations from the blank. For this purpose we developed a dynamic model for

318

Molecular and Physiological Properties Associated with Zebra Complex Disease in Potatoes and Its Relation with Candidatus Liberibacter Contents in Psyllid Vectors  

OpenAIRE

Zebra complex (ZC) disease on potatoes is associated with Candidatus Liberibacter solanacearum (CLs), an ?-proteobacterium that resides in the plant phloem and is transmitted by the potato psyllid Bactericera cockerelli (Šulc). The name ZC originates from the brown striping in fried chips of infected tubers, but the whole plants also exhibit a variety of morphological features and symptoms for which the physiological or molecular basis are not understood. We determined that compared to heal...

Alvarado, Veria Y.; Odokonyero, Denis; Duncan, Olivia; Mirkov, T. Erik; Scholthof, Herman B.

2012-01-01

319

Learning-Related Neuronal Activation in the Zebra Finch Song System Nucleus HVC in Response to the Bird’s Own Song  

OpenAIRE

Like many other songbird species, male zebra finches learn their song from a tutor early in life. Song learning in birds has strong parallels with speech acquisition in human infants at both the behavioral and neural levels. Forebrain nuclei in the ‘song system’ are important for the sensorimotor acquisition and production of song, while caudomedial pallial brain regions outside the song system are thought to contain the neural substrate of tutor song memory. Here, we exposed three groups...

Bolhuis, Johan J.; Gobes, Sharon M. H.; Terpstra, Nienke J.; Den Boer-visser, Ardie M.; Zandbergen, Matthijs A.

2012-01-01

320

The Gain Modulation by N-methyl-D-aspartate in the Projection Neurons of Robust Nucleus of the Arcopallium in Adult Zebra Finches  

OpenAIRE

The song of zebra finch is stable in life after it was learned successfully. Vocal plasticity is thought to be a motor exploration that can support continuous learning and optimization of performance. The activity of RA, an important pre-motor nucleus in songbird's brain, influences the song directly. This variability in adult birdsong is associated with the activity of NMDA receptors in LMAN-RA synapses, but the detailed mechanism is unclear. The control of gain refers to modulation of a neu...

Dong-Feng Li; Cong-Shu Liao; Xuan Pan; Guo-Qiang Hou; Su-Qun Liao

2012-01-01

321

A pollution-monitoring pilot study involving contaminant and biomarker measurements in the Seine Estuary, France, using zebra mussels (Dreissena polymorpha)  

OpenAIRE

Zebra mussel (Dreissena polymorpha) is an invasive species that has proliferated in European and North American rivers and lakes during the last century. In this study, D. polymorpha has been used to provide information on contamination levels and biological effects in the Seine Estuary (France). The bivalves accumulated polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) to a high degree with values reaching 800 ng/g dry weight for PCBs (sum of 20 congeners), and 1,0...

Minier, Christophe; Abarnou, Alain; Jaouen Madoulet, Agnes; Le Guellec, Anne-marie; Tutundjian, Renaud; Bocquene, Gilles; Leboulenger, Franc?ois

2006-01-01

322

Evolutionary relationships and functional conservation among vertebrate Max-associated proteins: the zebra fish homolog of Mxi1.  

Science.gov (United States)

In mammals, current evidence supports the view that Myc-responsive activities are regulated in part through an intracellular balance between levels of transcriptionally-active Myc/Max heterodimers and those of transcriptionally-inert Max/Max, Mad/Max and Mxi1/Max complexes. To gain insight into the roles of Mad and Mxi1 in cellular growth and differentiation and to fortify key structure-function relationships from an evolutionary standpoint, low stringency hybridization screens were used to identify potential homologs of these Max-associated proteins in the zebra fish genome. A single class of cDNA clones that cross-hybridized both to human mad and mxi1 probes was shown to encode a putative protein with significantly greater homology to mammalian Mxi1 than to Mad, particularly in the basic and helix-loop-helix (bHLH) regions. The high degree of structural relatedness between vertebrate Mxi1 proteins apparent in molecular modelling studies was consistent with the findings that the HLH/leucine zipper (LZ) region of zMxi1 exhibited the same profile of dimerization specificities as its mammalian counterpart in the two-hybrid system and that zmxi1 could, like human mxi1 (Lahoz et al., 1994), suppress the oncogenic potential of mouse c-myc in a mammalian cell. Finally, a comparison of steady-state zc-myc and zmxi1 mRNA levels during zebra fish embryogenesis demonstrated (i) high levels of zc-myc relative to zmxi1 mRNA during initiation of organogenesis, a period characterized by intense growth and active differentiation and (ii) rising levels of zmxi1 mRNA during progression towards the terminally differentiated state. These contrasting patterns of developmental expression together with the capacity of zmxi1 to repress myc-induced transformation support a model for the regulation, by Max-associated proteins, of Myc functions in the control of normal cell development and neoplastic growth. PMID:7936639

Schreiber-Agus, N; Chin, L; Chen, K; Torres, R; Thomson, C T; Sacchettini, J C; DePinho, R A

1994-11-01

323

Group-reactive ELISAs for detecting antibodies to African horsesickness and equine encephalosis viruses in horse, donkey, and zebra sera.  

Science.gov (United States)

Group-reactive enzyme-linked immunosorbent assays (ELISAs) were developed to selectively detect antibodies to African horsesickness virus (AHSV) and equine encephalosis virus (EEV), 2 orbiviruses that infect equids. In indirect ELISA, guinea pig antisera to all known AHSV or EEV serotypes recognized immobilized AHSV serotype 3 or EEV Cascara, respectively. Antisera from naturally infected animals did not cross-react with their respective heterologous viruses. The ELISA was used in parallel with the complement fixation (CF) and agar gel immunodiffusion tests to detect antibodies in sera from animals in the field. The ELISA distinguished among those that contained antibodies to AHSV, EEV, or both viruses and was useful with sera that did not yield results in CF tests because of anticomplementary activity. Zebra and donkeys, both potential subclinical carrier animals in Africa, contained AHSV or EEV antibodies. Some sera reacted with 1 of the 2 orbiviruses, whereas others reacted with both. The ELISA can be used in projected epidemiological studies in which many serum samples must be assayed. PMID:8385502

Williams, R; Du Plessis, D H; Van Wyngaardt, W

1993-01-01

324

Heterochromatin and histone modifications in the germline-restricted chromosome of the zebra finch undergoing elimination during spermatogenesis.  

Science.gov (United States)

In the zebra finch (Taeniopygia guttata) a germline-restricted chromosome (GRC) is regularly present in males and females. While the GRC is euchromatic in oocytes, in spermatocytes this chromosome is cytologically seen as entirely heterochromatic and presumably inactive. At the end of male meiosis, the GRC is eliminated from the nucleus. By immunofluorescence on microspreads, we investigated HP1 proteins and histone modifications throughout male meiotic prophase, as well as in young spermatid stages after the GRC elimination. We found that in prophase spermatocytes the GRC chromatin differs from that of the regular chromosome complement. The GRC is highly enriched in HP1 beta and exhibits high levels of di- and tri-methylated histone H3 at lysine 9 and tri- and di-methylated histone H4 at lysine 20. The GRC does not exhibit neither detectable levels of di- and tri-methylated histone H3 at lysine 4 nor acetylated histone H4 at lysine 5 and 8. The results prove the heterochromatic organization of the GRC in male germline and strongly suggest its transcriptional inactive state during male prophase. Following elimination, in young spermatids the GRC lacks HP1 beta signals but maintains high levels of methylated histone H3 at lysine 9 and methylated histone H4 at lysine 20. The release of HP1 from the GRC with respect to its elimination is discussed. PMID:20217426

Goday, Clara; Pigozzi, María Inés

2010-06-01

325

Analysis of Implosion and Radiative Properties of Ag Single Planar Wire Array Z-pinches on Zebra at UNR*  

Science.gov (United States)

Silver is the highest atomic number element (z = 47) to be investigated for L-shell radiative characteristics at 1.0MA on the Zebra pulsed-power generator at UNR and has been shown to produce radiation yields up to 29kJ in planar wire arrays (PWAs). Silver is also expected to reach the highest electron temperature for PWAs. In order to investigate this more thoroughly, the results of experiments with two Ag single PWA implosions are explored using a full diagnostic suite. In particular, implosion and radiative characteristics of the two single PWA loads, one consisting of eight 15?m Ag wires (M ˜ 296 ?g) and another of nearly identical mass consisting of seven 15?m Ag wires and one 30?m Al wire, are analyzed over a broad spectral range, from 15eV to 10keV. Synthetic spectra produced by a new non-LTE kinetic model of Ag are compared to the results of spatially resolved time-integrated x-ray spectroscopy to assess L-shell Ag plasma parameters and their axial gradients. The importance of the continued study of Ag PWAs is also discussed. *This work was supported by NNSA under DOE Cooperative Agreements DE-FC52-06NA27588, DE-FC52-06NA27586, and in part by DE-FC52-06NA27616.

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

2010-11-01

326

Body condition and immune response in wild zebra finches: effects of capture, confinement and captive-rearing  

Science.gov (United States)

Behavioural ecologists attempt to predict fitness in birds from estimates of body condition and immune capacity. We investigated how the stresses associated with capture, confinement and captive-rearing of wild zebra finches (Taeniopygia guttata) affected different elements of the immune system and body condition. Wild birds had higher heterophil:lymphocyte ratios and total leucocyte counts than aviary birds, presumably an outcome of mounting specific resistance to pathogens, but this response diminished significantly within 10 days of confinement. Wild birds had lower phytohaemagglutinin-A (PHA) responses than their aviary-bred counterparts possibly because energetic costs limited a general resistance response. Wild birds were heavier and had higher haematocrits than their aviary counterparts, but had less fat, although just 10 days of captivity significantly increased fat levels. Measures of body condition were of limited use for predicting immune responsiveness. We conclude that the different elements of the immune system and body condition respond independently, and often unpredictably, to many ecological and behavioural stressors.

Ewenson, Erynne; Zann, Richard; Flannery, Graham

2001-08-01

327

Effects of nutritional stress during different developmental periods on song and the hypothalamic-pituitary-adrenal axis in zebra finches.  

Science.gov (United States)

In songbirds, developmental stress affects song learning and production. Altered hypothalamic-pituitary-adrenal (HPA) axis function resulting in elevated corticosterone (CORT) may contribute to this effect. We examined whether developmental conditions affected the association between adult song and HPA axis function, and whether nutritional stress before and after nutritional independence has distinct effects on song learning and/or vocal performance. Zebra finches (Taeniopygia guttata) were raised in consistently high (HH) or low (LL) food conditions until post-hatch day (PHD) 62, or were switched from high to low conditions (HL) or vice versa (LH) at PHD 34. Song was recorded in adulthood. We assessed the response of CORT to handling during development and to dexamethasone (DEX) and adrenocorticotropic hormone (ACTH) challenges during adulthood. Song learning and vocal performance were not affected by nutritional stress at either developmental stage. Nutritional stress elevated baseline CORT during development. Nutritional stress also increased rate of CORT secretion in birds that experienced stress only in the juvenile phase (HL group). Birds in the LL group had lower CORT levels after injection of ACTH compared to the other groups, however there was no effect of nutritional stress on the response to DEX. Thus, our findings indicate that developmental stress can affect HPA function without concurrently affecting song. PMID:24417905

Kriengwatana, B; Wada, H; Schmidt, K L; Taves, M D; Soma, K K; MacDougall-Shackleton, S A

2014-03-01

328

Arrhythmic Song Exposure Increases ZENK Expression in Auditory Cortical Areas and Nucleus Taeniae of the Adult Zebra Finch  

Science.gov (United States)

Rhythm is important in the production of motor sequences such as speech and song. Deficits in rhythm processing have been implicated in human disorders that affect speech and language processing, including stuttering, autism, and dyslexia. Songbirds provide a tractable model for studying the neural underpinnings of rhythm processing due to parallels with humans in neural structures and vocal learning patterns. In this study, adult zebra finches were exposed to naturally rhythmic conspecific song or arrhythmic song. Immunohistochemistry for the immediate early gene ZENK was used to detect neural activation in response to these two types of stimuli. ZENK was increased in response to arrhythmic song in the auditory association cortex homologs, caudomedial nidopallium (NCM) and caudomedial mesopallium (CMM), and the avian amygdala, nucleus taeniae (Tn). CMM also had greater ZENK labeling in females than males. The increased neural activity in NCM and CMM during perception of arrhythmic stimuli parallels increased activity in the human auditory cortex following exposure to unexpected, or perturbed, auditory stimuli. These auditory areas may be detecting errors in arrhythmic song when comparing it to a stored template of how conspecific song is expected to sound. CMM may also be important for females in evaluating songs of potential mates. In the context of other research in songbirds, we suggest that the increased activity in Tn may be related to the value of song for assessing mate choice and bonding or it may be related to perception of arrhythmic song as aversive. PMID:25259620

Lampen, Jennifer; Jones, Katherine; McAuley, J. Devin; Chang, Soo-Eun; Wade, Juli

2014-01-01

329

Encoding of naturalistic optic flow by motion sensitive neurons of nucleus rotundus in the zebra finch (Taeniopygia guttata.  

Directory of Open Access Journals (Sweden)

Full Text Available The retinal image changes that occur during locomotion, the optic flow, carry information about self-motion and the three-dimensional structure of the environment. Especially fast moving animals with only little binocular vision depend on these depth cues for manoeuvring. They actively control their gaze to facilitate perception of depth based on cues in the optic flow. In the visual system of birds, nucleus rotundus neurons were originally found to respond to object motion but not to background motion. However, when background and object were both moving, responses increase the more the direction and velocity of object and background motion on the retina differed. These properties may play a role in representing depth cues in the optic flow. We therefore investigated how neurons in nucleus rotundus respond to optic flow that contains depth cues. We presented simplified and naturalistic optic flow on a panoramic LED display while recording from single neurons in nucleus rotundus of anaesthetized zebra finches. Unlike most studies on motion vision in birds, our stimuli included depth information. We found extensive responses of motion selective neurons in nucleus rotundus to optic flow stimuli. Simplified stimuli revealed preferences for optic flow reflecting translational or rotational self-motion. Naturalistic optic flow stimuli elicited complex response modulations, but the presence of objects was signalled by only few neurons. The neurons that did respond to objects in the optic flow, however, show interesting properties.

DennisEckmeier

2013-09-01

330

Systemic Amyloidosis and Testicular Interstitial Tumor in a Zebra Finch (Taeniopygia guttata: a Case Report in Iran  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Systemic amyloidosis and testicular interstitial tumor are rare conditions in birds and this is the first report in Iran. A male zebra finch was presented because of white diarrhea, anorexia, loss of weight and lethargy. At necropsy, the small intestine was edematous and congested. The spleen appeared pale. The liver was large, firm and brown. One testis was cystic and neoplastic and the remaining testis was atrophic. Histologically, amyloid materials were seen predominantly in the liver and spleen. Hyaline substances were deposited in the Disse space and in the media of blood vessels of the liver. In spleen, marked deposits thickened the basement membranes of blood vessels and extended into the surrounding parenchyma. In addition, there were lesser degrees of amyloidosis in other organs such as small intestine. Amyloid stained positively with Congo red. In testis, there was encapsulated unilateral interstitial cell tumor, with multiple foci of necrosis and hemorrhage. The neoplastic cells were round to polyhedral, with small round hyperchromatic nuclei and finely vacuolated cytoplasm. Signs of feminization were observed. The cause of amyloidosis in this study was not conclusively identified.

Mehrnoush Moeini Jazani

2011-09-01

331

Vigilance behaviour and its endocrine correlates in Plains zebra (Equus burchelli) living in a predator-free landscape  

OpenAIRE

Group size affects individual and collective vigilance levels of prey species. As individual vigilance decreases with increasing group size, the indirect risk of predation to each individual and the group as a whole will also decrease (dilution and many-eyes effect) which may have a decreasing effect on stress responses on group level as well. Where predation risk is low, other factors like group size might influence stress-related glucocorticoid output in prey species. I test the relationshi...

Fourie, Clasina Elizabeth

2012-01-01

332

Enhanced Expression of Tubulin Specific Chaperone Protein A, Mitochondrial Ribosomal Protein S27, and the DNA Excision Repair Protein XPACCH in the Song System of Juvenile Male Zebra Finches  

OpenAIRE

Recent evidence suggests that sexual dimorphisms in the zebra finch song system and behavior arise due to factors intrinsic to the brain, rather than being solely organized by circulating steroid hormones. The present study examined expression of ten sex-chromosome genes in the song system of 25-day-old zebra finches in an attempt to further elucidate these factors. Increased expression in males was confirmed for nine of the genes by real-time qPCR using cDNA from individual whole telecephalo...

Qi, Linda M.; Mohr, Margaret; Wade, Juli

2012-01-01

333

Compact hohlraum configuration with parallel planar-wire-array x-ray sources at the 1.7-MA Zebra generator  

Science.gov (United States)

A compact Z-pinch x-ray hohlraum design with parallel-driven x-ray sources is experimentally demonstrated in a configuration with a central target and tailored shine shields at a 1.7-MA Zebra generator. Driving in parallel two magnetically decoupled compact double-planar-wire Z pinches has demonstrated the generation of synchronized x-ray bursts that correlated well in time with x-ray emission from a central reemission target. Good agreement between simulated and measured hohlraum radiation temperature of the central target is shown. The advantages of compact hohlraum design applications for multi-MA facilities are discussed.

Kantsyrev, V. L.; Chuvatin, A. S.; Rudakov, L. I.; Velikovich, A. L.; Shrestha, I. K.; Esaulov, A. A.; Safronova, A. S.; Shlyaptseva, V. V.; Osborne, G. C.; Astanovitsky, A. L.; Weller, M. E.; Stafford, A.; Schultz, K. A.; Cooper, M. C.; Cuneo, M. E.; Jones, B.; Vesey, R. A.

2014-12-01

334

Validation of an egg-injection method for testing in ovo toxicity of PBDE-99 in a small songbird model species, the zebra finches (Taeniopygia guttata)  

OpenAIRE

Egg injection was validated for studies of in ovo exposure to xenobiotics in the zebra finch (Taeniopygia guttata). Puncturing eggs and injecting DMSO had no effect on embryo development or hatching success, but DMSO negatively affected post-hatching growth in males. In ovo injection was used to test the long-term, inter-generational effects of embryonic exposure to the polybrominated diphenyl ether PBDE-99. Eggs were dosed at 10, 100 and 1000 ng/egg and chicks, their offspring and grand-offs...

Khamzina, Viktoria

2011-01-01

335

Estrogen-inducible, sex-specific expression of brain-derived neurotrophic factor mRNA in a forebrain song control nucleus of the juvenile zebra finch  

OpenAIRE

The expression of brain-derived neurotrophic factor (BDNF) mRNA is increased significantly within the high vocal center (HVc) of male but not female zebra finches from posthatching day 30–35 on. The population of HVc cells expressing BDNF mRNA included 35% of the neurons projecting to the nucleus robustus of the archistriatum (RA). In the RA and in RA-projecting neurons of the lateral portion of the magnocellular nucleus of the anterior neostriatum, BDNF mRNA was expressed at very low level...

Dittrich, F.; Feng, Y.; Metzdorf, R.; Gahr, M.

1999-01-01

336

The Black Cuckoo-Shrike Campephaga flava: A new record for the Mountain Zebra National Park and the Cradock district, Cape Province  

OpenAIRE

The avifauna of the Mountain Zebra National Park (MZNP) has been recorded over a period of some two decades (Skead 1965, Koedoe 8: 1-40; Penzhorn & Bronkhorst 1976, Koedoe 19: 171-174; Penzhorn 1977, Koedoe 20: 205-207; Grobler & Bronkhorst 1981, Koedoe 24: 199-203). Collett (1982 Southern Birds 9: 1-65) has summarised all the available information on the avifauna of the Cradock district assembled since the turn of the century. Although 203 species are recorded from the MZNP by these ...

Macdonald, I. A. W.

1984-01-01

337

Validation of an egg-injection method for embryotoxicity studies in a small, model songbird, the zebra finch (Taeniopygia guttata).  

Science.gov (United States)

Female birds deposit or 'excrete' lipophilic contaminants to their eggs during egg formation. Concentrations of xenobiotics in bird eggs can therefore accurately indicate levels of contamination in the environment and sampling of bird eggs is commonly used as a bio-monitoring tool. It is widely assumed that maternally transferred contaminants cause adverse effects on embryos but there has been relatively little experimental work confirming direct developmental effects (cf. behaviorally-mediated effects). We validated the use of egg injection for studies of in ovo exposure to xenobiotics for a small songbird model species, the zebra finch (Taeniopygia guttata), where egg weight averages only 1 g. We investigated a) the effect of puncturing eggs with or without vehicle (DMSO) injection on egg fate (embryo development), chick hatching success and subsequent growth to 90 days (sexual maturity), and b) effects of two vehicle solutions (DMSO and safflower oil) on embryo and chick growth. PBDE-99 and -47 were measured in in ovo PBDE-treated eggs, chicks and adults to investigate relationships between putative injection amounts and the time course of metabolism (debromination) of PBDE-99 during early development. We successfully injected a small volume (5 ?L) of vehicle into eggs, at incubation day 0, with no effects on egg or embryo fate and with hatchability similar to that for non-manipulated eggs in our captive-breeding colony (43% vs. 48%). We did find some evidence for an inhibitory effect of DMSO vehicle on post-hatching chick growth, in male chicks only. This method can be used to treat eggs in a dose-dependent, and ecologically-relevant, manner with PBDE-99, based on chemical analysis of eggs, hatchling and adults. PMID:22959718

Winter, V; Elliott, J E; Letcher, R J; Williams, T D

2013-01-01

338

Study of the biological effects of uranium exposure on zebra fish (D. rerio). Impact on life stages  

International Nuclear Information System (INIS)

This work is part of an ongoing project (ENVIRHOM) started at IRSN in 2000, which consists in studying the environmental effects of radioactive substances at chronic low level of exposure. In this general frame, our aim was two fold: (i) to identify sensitivity of different critical life stages of zebra fish (fish of fresh water frequently used for tests standards in ecotoxicology) to uranium exposure and (ii) to evaluate underlying mechanisms. Experiments were conducted with eggs, larvae and genitors exposed to uranium at environmentally relevant concentrations (from 20 to 500 ?g/L) in order to study survival, hatching of eggs, growth of larvae and reproduction of genitors. Bio-markers of exposure (i.e. U bioaccumulation) and bio-markers of effects at molecular level (i.e. genotoxic effects, reproductive-toxicity) were also measured. Sensitivity of fish to uranium was dependent of the life stage of development with the early life stage being the most sensitive to U either directly or maternally exposed. It underlines the relevance of including pro-larval stages for toxicity assessments in fish. Moreover drastic effects of uranium on reproductive success and DNA damages in the germ cells foretell a strong impact on the population for low concentration of exposure (20 ?g/L). As it is increasingly recognized that population-level effects of toxic substances are more relevant in terms of ecological risk assessment, this study points out the need to include different life stages of organisms in eco-toxicological studies, especially the sensitive early stages. Moreover, it appears, through the comparative study of the radiological effects or by another isotope of the uranium of stronger radioactivity (233U or by an irradiation with 137Cs), that the effects of the uranium are due to its chemo-toxicity. (author)

339

Diversity of endosymbionts in the potato psyllid, Bactericera cockerelli (Triozidae), vector of zebra chip disease of potato.  

Science.gov (United States)

Zebra chip disease is an emerging, serious disease of solanaceous crops and the causal agent is a bacterium "Candidatus Liberibacter solanacearum" (CLs), also known as "Candidatus Liberibacter psyllaurous", which is transmitted by the potato psyllid, Bactericera cockerelli (Šulc). We performed bacterial tag-encoded FLX amplicon pyrosequencing (bTEFAP) of the 16S rDNA genes to determine the bacterial microbiota in adult insects from CLs-uninfected and CLs-infected strains of B. cockerelli and potato leaf samples. We obtained sequences from five bacterial species among the two psyllid strains, including "Candidatus Carsonella ruddii", Wolbachia, CLs, and two transient bacteria, Acinetobacter and Methylibium. We did not detect any common bacteria between psyllids and potato leaf samples using pyrosequencing. We performed PCR analysis using species-specific 16S rDNA primers to confirm pyrosequencing results in individual psyllids including eggs, early-instars, late-instars, and adults of both sexes from both CLs-uninfected and CLs-infected psyllid strains. The primary endosymbiont, "Candidatus Carsonella ruddii" and Wolbachia were detected in all life-stages and sexes of both strains using PCR analyses. The percentage of CLs-infected individuals increased from early-instar (0%), late-instar (40%) until adulthood (60%) in the CLs-infected strain. We believe that CLs levels in early-instars are probably too low to be detected by standard PCR. Using PCR analyses, we confirmed the presence of Acinetobacter in CLs-uninfected and CLs-infected adults (75 and 25%, respectively) but not Methylibium. Further, we detected Acinetobacter in potato leaves using PCR indicating that the psyllids may have acquired this bacterium via feeding on the host plant. PMID:21327558

Nachappa, Punya; Levy, Julien; Pierson, Elizabeth; Tamborindeguy, Cecilia

2011-05-01

340

Effects of housing condition and early corticosterone treatment on learned features of song in adult male zebra finches.  

Science.gov (United States)

Early developmental stress can have long-term physiological and behavioral effects on an animal. Developmental stress and early corticosterone (Cort) exposure affect song quality in many songbirds. Early housing condition can act as a stressor and affect the growth of nestlings and adult song, and improvements in housing condition can reverse adverse effects of early stress exposure in rodents. However, little is known about this effect in songbirds. Therefore, we took a novel approach to investigate if housing condition can modify the effects of early Cort exposure on adult song in male zebra finches. We manipulated early housing conditions to include breeding in large communal flight cages (FC; standard housing condition; with mixed-sex and mix-aged birds) versus individual breeding cages (IBC, one male-female pair with small, IBC-S, or large clutches, IBC-L) in post-hatch Cort treated male birds. We found that Cort treated birds from IBC-S have higher overall song learning scores (between tutor and pupil) than from FC but there is no difference between these groups in the No-Cort treated birds. When examining the effects of Cort within each housing condition, overall song learning scores decreased in Cort treated birds from flight cages but increased in birds from IBC-S compared to controls. Likewise, the total number of syllables and syllable types increased significantly in Cort treated birds from IBC-S, but decreased in FC-reared birds though this effect was not statistically significant. These findings suggest that the effects of early Cort treatment on learned features of song depend on housing condition. PMID:24492024

Shahbazi, Mahin; Jimenez, Pedro; Martinez, Luis A; Carruth, Laura L

2014-03-01

341

Correlates of male fitness in captive zebra finches - a comparison of methods to disentangle genetic and environmental effects  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Backgound It is a common observation in evolutionary studies that larger, more ornamented or earlier breeding individuals have higher fitness, but that body size, ornamentation or breeding time does not change despite of sometimes substantial heritability for these traits. A possible explanation for this is that these traits do not causally affect fitness, but rather happen to be indirectly correlated with fitness via unmeasured non-heritable aspects of condition (e.g. undernourished offspring grow small and have low fitness as adults due to poor health. Whether this explanation applies to a specific case can be examined by decomposing the covariance between trait and fitness into its genetic and environmental components using pedigree-based animal models. We here examine different methods of doing this for a captive zebra finch population where male fitness was measured in communal aviaries in relation to three phenotypic traits (tarsus length, beak colour and song rate. Results Our case study illustrates how methods that regress fitness over breeding values for phenotypic traits yield biased estimates as well as anti-conservative standard errors. Hence, it is necessary to estimate the genetic and environmental covariances between trait and fitness directly from a bivariate model. This method, however, is very demanding in terms of sample sizes. In our study parameter estimates of selection gradients for tarsus were consistent with the hypothesis of environmentally induced bias (?A = 0.035 ± 0.25 (SE, ?E = 0.57 ± 0.28 (SE, yet this differences between genetic and environmental selection gradients falls short of statistical significance. Conclusions To examine the generality of the idea that phenotypic selection gradients for certain traits (like size are consistently upwardly biased by environmental covariance a meta-analysis across study systems will be needed.

Bolund Elisabeth

2011-11-01

342

The songbird syrinx morphome: a three-dimensional, high-resolution, interactive morphological map of the zebra finch vocal organ  

DEFF Research Database (Denmark)

Background: Like human infants, songbirds learn their species-specific vocalizations through imitation learning. The birdsong system has emerged as a widely used experimental animal model for understanding the underlying neural mechanisms responsible for vocal production learning. However, how neural impulses are translated into the precise motor behavior of the complex vocal organ (syrinx) to create song is poorly understood. First and foremost, we lack a detailed understanding of syringeal morphology. Results: To fill this gap we combined non-invasive (high-field magnetic resonance imaging and micro-computed tomography) and invasive techniques (histology and micro-dissection) to construct the annotated high-resolution three-dimensional dataset, or morphome, of the zebra finch (Taeniopygia guttata) syrinx. We identified and annotated syringeal cartilage, bone and musculature in situ in unprecedented detail. We provide interactive three-dimensional models that greatly improve the communication of complex morphological data and our understanding of syringeal function in general. Conclusions: Our results show that the syringeal skeleton is optimized for low weight driven by physiological constraints on song production. The present refinement of muscle organization and identity elucidates how apposed muscles actuate different syringeal elements. Our dataset allows for more precise predictions about muscle co-activation and synergies and has important implications for muscle activity and stimulation experiments. We also demonstrate how the syrinx can be stabilized during song to reduce mechanical noise and, as such, enhance repetitive execution of stereotypic motor patterns. In addition, we identify a cartilaginous structure suited to play a crucial role in the uncoupling of sound frequency and amplitude control, which permits a novel explanation of the evolutionary success of songbirds.

During, D. N.; Ziegler, A.

2013-01-01

343

The songbird syrinx morphome: a three-dimensional, high-resolution, interactive morphological map of the zebra finch vocal organ  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Like human infants, songbirds learn their species-specific vocalizations through imitation learning. The birdsong system has emerged as a widely used experimental animal model for understanding the underlying neural mechanisms responsible for vocal production learning. However, how neural impulses are translated into the precise motor behavior of the complex vocal organ (syrinx to create song is poorly understood. First and foremost, we lack a detailed understanding of syringeal morphology. Results To fill this gap we combined non-invasive (high-field magnetic resonance imaging and micro-computed tomography and invasive techniques (histology and micro-dissection to construct the annotated high-resolution three-dimensional dataset, or morphome, of the zebra finch (Taeniopygia guttata syrinx. We identified and annotated syringeal cartilage, bone and musculature in situ in unprecedented detail. We provide interactive three-dimensional models that greatly improve the communication of complex morphological data and our understanding of syringeal function in general. Conclusions Our results show that the syringeal skeleton is optimized for low weight driven by physiological constraints on song production. The present refinement of muscle organization and identity elucidates how apposed muscles actuate different syringeal elements. Our dataset allows for more precise predictions about muscle co-activation and synergies and has important implications for muscle activity and stimulation experiments. We also demonstrate how the syrinx can be stabilized during song to reduce mechanical noise and, as such, enhance repetitive execution of stereotypic motor patterns. In addition, we identify a cartilaginous structure suited to play a crucial role in the uncoupling of sound frequency and amplitude control, which permits a novel explanation of the evolutionary success of songbirds.

Düring Daniel N

2013-01-01

344

Calculations to compare different ways of modelling the plate geometry cells of the Zebra fast critical assembly, MZA  

International Nuclear Information System (INIS)

The core region cells of the Zebra fast critical assembly MZA comprise 14 plates in a square steel tube, with 12 cells being stacked axially to form the core section of the assembly. The cells can be modelled in different levels of detail, ranging from a three-dimensional representation in which the core (The word core is used to describe both the region of a plate containing the main material, such as plutonium, UO2 or sodium, and the region of the assembly containing fissile material cells.) and canning regions of the plates and the void gaps between the edges of the plates and the steel tube, and between tubes, are represented. Simplified models include a three-dimensional representation in which the void regions are combined with the tube material. A further simplified three-dimensional model, called the MURAL model, represents the core regions of the plates but homogenises the canning, tube material and void regions. Two types of one-dimensional slab geometry model are found in the literature, one in which the materials are homogenised within each of the three axial slab regions of a canned plate (plate core and upper and lower canning regions) and a further simplified version in which the plate is modelled as a single region, the compositions being averaged over the whole thickness of the plate, comprising the plate core material, the canning and the tube material. MONK Monte Carlo calculations have been made for each of these models, and also for thefor each of these models, and also for the fully homogenised cells, and the k-effective values, core sodium void reactivities and reaction rate ratios are compared

345

Mass production of SNP markers in a nonmodel passerine bird through RAD sequencing and contig mapping to the zebra finch genome.  

Science.gov (United States)

Here, we present an adaptation of restriction-site-associated DNA sequencing (RAD-seq) to the Illumina HiSeq2000 technology that we used to produce SNP markers in very large quantities at low cost per unit in the Réunion grey white-eye (Zosterops borbonicus), a nonmodel passerine bird species with no reference genome. We sequenced a set of six pools of 18-25 individuals using a single sequencing lane. This allowed us to build around 600 000 contigs, among which at least 386 000 could be mapped to the zebra finch (Taeniopygia guttata) genome. This yielded more than 80 000 SNPs that could be mapped unambiguously and are evenly distributed across the genome. Thus, our approach provides a good illustration of the high potential of paired-end RAD sequencing of pooled DNA samples combined with comparative assembly to the zebra finch genome to build large contigs and characterize vast numbers of informative SNPs in nonmodel passerine bird species in a very efficient and cost-effective way. PMID:23855484

Bourgeois, Yann X C; Lhuillier, Emeline; Cézard, Timothée; Bertrand, Joris A M; Delahaie, Boris; Cornuault, Josselin; Duval, Thomas; Bouchez, Olivier; Milá, Borja; Thébaud, Christophe

2013-09-01

346

Two-photon deep imaging through skin and skull of Zebra finches: preliminary studies for in-vivo brain metabolism monitoring  

Science.gov (United States)

Zebra Finches are songbirds which constitute a model for neuro-ethologists to study the neuro-mechanisms of vocal recognition. For this purpose, in vivo and non invasive monitoring of brain activity is required during acoustical stimulation. MRI (Magnetic Resonance Imaging) or NIRS (Near InfraRed Spectroscopy) are suitable methods for these measurements, even though MRI is difficult to link quantitatively with neural activity and NIRS suffers from a poor resolution. In the particular case of songbirds (whose skin is thin and quite transparent and whose skull structure is hollow), two-photon microscopy enables a quite deep penetration in tissues and could be an alternative. We present here preliminary studies on the feasability of two-photon microscopy in these conditions. To do so, we chose to image hollow fibers, filled with Rhodamine B, through the skin of Zebra finches in order to evaluate the spatial resolution we may expect in future in vivo experiments. Moreover, we used the reflectance-mode confocal configuration to evaluate the exponential decrease of backreflected light in skin and in skull samples. Following this procedure recently proposed by S.L. Jacques and co-workers, we planned to determine the scattering coefficient ? s and the anisotropy g of these tissues and make a comparison between fixed and fresh skin and skull samples for future Monte Carlo simulations of the scattering in our particular multi-layered structure.

Abi-Haidar, D.; Olivier, T.; Mottin, S.; Vignal, C.; Mathevon, N.

2007-02-01

347

Psychological essentialist reasoning and perspective taking during reading: a donkey is not a zebra, but a plate can be a clock.  

Science.gov (United States)

In an eyetracking study, we examined whether readers use psychological essentialist reasoning and perspective taking online. Stories were presented in which an animal or an artifact was transformed into another animal (e.g., a donkey into a zebra) or artifact (e.g., a plate into a clock). According to psychological essentialism, the essence of the animal did not change in these stories, while the transformed artifact would be thought to have changed categories. We found evidence that readers use this kind of reasoning online: When reference was made to the transformed animal, the nontransformed term ("donkey") was preferred, but the opposite held for the transformed artifact ("clock" was read faster than "plate"). The immediacy of the effect suggests that this kind of reasoning is employed automatically. Perspective taking was examined within the same stories by the introduction of a novel story character. This character, who was naïve about the transformation, commented on the transformed animal or artifact. If the reader were to take this character's perspective immediately and exclusively for reference solving, then only the transformed term ("zebra" or "clock") would be felicitous. However, the results suggested that while this character's perspective could be taken into account, it seems difficult to completely discard one's own perspective at the same time. PMID:22037846

Frisson, Steven; Wakefield, Mary

2012-02-01

348

Functional genomic analysis and neuroanatomical localization of miR-2954, a song-responsive sex-linked microRNA in the zebra finch  

Science.gov (United States)

Natural experience can cause complex changes in gene expression in brain centers for cognition and perception, but the mechanisms that link perceptual experience and neurogenomic regulation are not understood. MicroRNAs (miRNAs or miRs) have the potential to regulate large gene expression networks, and a previous study showed that a natural perceptual stimulus (hearing the sound of birdsong in zebra finches) triggers rapid changes in expression of several miRs in the auditory forebrain. Here we evaluate the functional potential of one of these, miR-2954, which has been found so far only in birds and is encoded on the Z sex chromosome. Using fluorescence in situ hybridization and immunohistochemistry, we show that miR-2954 is present in subsets of cells in the sexually dimorphic brain regions involved in song production and perception, with notable enrichment in cell nuclei. We then probe its regulatory function by inhibiting its expression in a zebra finch cell line (G266) and measuring effects on endogenous gene expression using Illumina RNA sequencing (RNA-seq). Approximately 1000 different mRNAs change in expression by 1.5-fold or more (adjusted p song stimulation itself triggers a decrease in miR-2954 expression followed by a delayed decrease in genes encoding ribosomal and mitochondrial functions, we suggest that miR-2954 may mediate some of the neurogenomic effects of song habituation. PMID:25565940

Lin, Ya-Chi; Balakrishnan, Christopher N.; Clayton, David F.

2014-01-01

349

Learning to cope with degraded sounds: female zebra finches can improve their expertise in discriminating between male voices at long distances.  

Science.gov (United States)

Reliable transmission of acoustic information about individual identity is of critical importance for pair bond maintenance in numerous monogamous songbirds. However, information transfer can be impaired by environmental constraints such as external noise or propagation-induced degradation. Birds have been shown to use several adaptive strategies to deal with difficult signal transmission contexts. Specifically, a number of studies have suggested that vocal plasticity at the emitter's level allows birds to counteract the deleterious effects of sound degradation. Although the communication process involves both the emitter and the receiver, perceptual plasticity at the receiver's level has received little attention. Here, we explored the reliability of individual recognition by female zebra finches (Taeniopygia guttata), testing whether perceptual training can improve discrimination of degraded individual vocal signatures. We found that female zebra finches are proficient in discriminating between calls of individual males at long distances, and even more so when they can train themselves with increasingly degraded signals over time. In this latter context, females succeed in discriminating between males as far as 250 m. This result emphasizes that adaptation to adverse communication conditions may involve not only the emitter's vocal plasticity but also the receptor's decoding process through on-going learning. PMID:24948627

Mouterde, Solveig C; Elie, Julie E; Theunissen, Frédéric E; Mathevon, Nicolas

2014-09-01

350

A pollution-monitoring pilot study involving contaminant and biomarker measurements in the Seine Estuary, France, using zebra mussels (Dreissena polymorpha).  

Science.gov (United States)

Zebra mussel (Dreissena polymorpha) is an invasive species that has proliferated in European and North American rivers and lakes during the last century. In this study, D. polymorpha has been used to provide information on contamination levels and biological effects in the Seine Estuary (France). The bivalves accumulated polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) to a high degree with values reaching 800 ng/g dry weight for PCBs (sum of 20 congeners), and 1,000 ng/g dry weight of PAHs (sum of 14 compounds) in the whole body. These values are among the highest reported of PCBs and, to a lesser extent, of PAHs in other contaminated areas in the world. Toxic equivalent quantities of PCBs and PAHs detected in zebra mussels varied from 20 to 40 pg dioxin equivalents/g dry weight for PCBs and up to 120 ng benzo[a]pyrene equivalents/ g dry weight for PAHs, indicating a high potential risk for animals feeding on them. Biological impacts, such as altered condition index, decreased lysosomal stability, and high levels of multixenobiotic resistance (MXR) proteins also were detected in mussels living downstream of Rouen, the main city of the Seine Estuary. Taken together, these results indicate that the Seine Estuary is a heavily polluted area with the potential to cause deleterious health effects in some endogenous living organisms. This study also shows that chemical and biological measurements bring different but complementary results that can help diagnose environmental health. PMID:16494231

Minier, Christophe; Abarnou, Alain; Jaouen-Madoulet, Agnès; Le Guellec, Anne-Marie; Tutundjian, Renaud; Bocquené, Gilles; Leboulenger, François

2006-01-01

351

Environmental concentrations of 3,4-methylenedioxymethamphetamine (MDMA)-induced cellular stress and modulated antioxidant enzyme activity in the zebra mussel.  

Science.gov (United States)

Recent monitoring studies showed measurable levels of the 3,4-methylenedioxymethamphetamine (MDMA) in aquatic environments. However, no information is currently available on its potential hazard to aquatic non-target organisms. The aim of this study was to investigate the potential sub-lethal effects induced by 14-day exposures to low MDMA concentrations (0.05 and 0.5 ?g/L) to zebra mussel (Dreissena polymorpha) specimens through the application of a biomarker suite. The trypan blue exclusion method and the neutral red retention assay (NRRA) were used to assess MDMA cytotoxicity. The activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione S-transferase (GST), as well as the lipid peroxidation (LPO) and protein carbonyl content (PCC), were measured as oxidative stress indexes. The single cell gel electrophoresis (SCGE) assay, the DNA diffusion assay, and the micronucleus test (MN test) were applied to investigate DNA damage, while filtration rate was measured as physiological parameter. Despite significant decrease in lysosome membrane stability, hemocyte viability and imbalances in CAT and GST activities pointed out at the end of the exposure to 0.5 ?g/L, no significant variations for the other end points were noticed at both the treatments, suggesting that environmentally relevant MDMA concentrations did not induce deleterious effects to the zebra mussel. PMID:24878561

Parolini, Marco; Magni, Stefano; Binelli, Andrea

2014-09-01

352

Molecular characterization and Phylogenetic analysis of 16S rRNA from a new Candidatus Liberibacter strain associated with Zebra chip disease of Potato (Solanum tuberosum L.) and the potato psyllid  

Science.gov (United States)

The full-length 16S rRNA gene region of a new Candidatus Liberibacter strain was PCR amplified from tubers of potato plants showing Zebra Chip (ZC) disease symptoms and also from the potato psyllid [Bactericera (= Paratrioza) cockerelli Sulc], the presumptive vector of the ZC disease causal agent. ...

353

A newly discovered superoantero-orbital sinus connecting to the interaural canal may play a role in zebra finch hearing  

DEFF Research Database (Denmark)

The middle ears of birds are acoustically connected through an air-filled pathway, the interaural canal (IAC), which allows sound to propagate internally from one ear to the other and considerably enhance the cues for directional hearing. The enhancement of the directional cues depends on the amplitude gain and time delay through IAC. Theoretically, different combinations of frequency dependent gains and delays produce very different directionalities of the ears but it is still uncertain how gain and delay can be shaped by evolution. We have discovered that a large forehead sinus superoanterior to the orbits (superoantero-orbital sinus, SAOS) connects to the IAC via a tube inferomedial to the orbits (IMT). SAOS has a very complex shape with connections through an arc over the eye to the bullae of each ear and also to two smaller lateral sinuses in front of each eye. The contribution of this structure to auditory sensitivity has not been studied previously. We hypothesized that the extra air volume could form a resonator influencing the gain and delay of IAC. We tested the hypothesis by measuring sound transmission through IAC of zebra finches before and after filling the SAOS with a silicone impression medium. Six out of seven individuals showed an effect of filling the SAOS or the IMT on directionality and overall auditory sensitivity. The SAOS therefore does seem to have an effect on gain and delay in the interaural canal as well as on auditory sensitivity. The effect, however, was complex and either significantly changed the gain by up to 10 dB in the frequency range below about 2-3 kHz and/or in a narrow band around 4-6 kHz. Although we verified the fillings by post-experimental dissection, it was difficult to determine exactly to what degree the different components were filled. Thus differential filling and/or blockage of the complex system may be the reason for complexity of the results. Future experiments aim for better control of the cavity filling.

Jensen, Kenneth Kragh; Christensen-Dalsgaard, Jakob

354

Distribution of aromatase-immunoreactive cells in the forebrain of zebra finches (Taeniopygia guttata): implications for the neural action of steroids and nuclear definition in the avian hypothalamus.  

Science.gov (United States)

Cells immunoreactive for the enzyme aromatase were localized in the forebrain of male zebra finches with the use of an immunocytochemistry procedure. Two polyclonal antibodies, one directed against human placental aromatase and the other directed against quail recombinant aromatase, revealed a heterogeneous distribution of the enzyme in the telencephalon, diencephalon, and mesencephalon. Staining was enhanced in some birds by the administration of the nonsteroidal aromatase inhibitor, R76713 racemic Vorozole) prior to the perfusion of the birds as previously described in Japanese quail. Large numbers of cells immunoreactive for aromatase were found in nuclei in the preoptic region and in the tuberal hypothalamus. A nucleus was identified in the preoptic region based on the high density of aromatase immunoreactive cells within its boundaries that appears to be homologous to the preoptic medial nucleus (POM) described previously in Japanese quail. In several birds alternate sections were stained for immunoreactive vasotocin, a marker of the paraventricular nucleus (PVN). This information facilitated the clear separation of the POM in zebra finches from nuclei that are adjacent to the POM in the preoptic area-hypothalamus, such as the PVN and the ventromedial nucleus of the hypothalamus. Positively staining cells were also detected widely throughout the telencephalon. Cells were discerned in the medial parts of the ventral hyperstriatum and neostriatum near the lateral ventricle and in dorsal and medial parts of the hippocampus. They were most abundant in the caudal neostriatum where they clustered in the dorsomedial neostriatum, and as a band of cells coursing along the dorsal edge of the lamina archistriatalis dorsalis. They were also present in high numbers in the ventrolateral aspect of the neostriatum and in the nucleus taeniae. None of the telencephalic vocal control nuclei had appreciable numbers of cells immunoreactive for aromatase within their boundaries, with the possible exception of a group of cells that may correspond to the medial part of the magnocellular nucleus of the neostriatum. The distribution of immunoreactive aromatase cells in the zebra finch brain is in excellent agreement with the distribution of cells expressing the mRNA for aromatase recently described in the finch telencephalon. This widespread telencephalic distribution of cells immunoreactive for aromatase has not been described in non-songbird species such as the Japanese quail, the ring dove, and the domestic fowl. PMID:8885196

Balthazart, J; Absil, P; Foidart, A; Houbart, M; Harada, N; Ball, G F

1996-10-01

355

Coronal Magnetic Field Strength from Decameter Zebra-Pattern Observations: Complementarity with Band-Splitting Measurements of an Associated Type II Burst  

Science.gov (United States)

A zebra pattern and a type II burst with band splitting were analyzed to study the coronal magnetic field in the height range of 1.9 - 2 solar radii. To this aim we used an extremely sensitive telescope (the Ukrainian decameter radio telescope, UTR-2) with a low-noise, high-dynamic-range spectrometer for the observations below 32 MHz. Based on the analysis of the spectral structures, the field strength obtained is 0.43 G. The value was found by fitting two different field indicators together under the assumptions that the shock wave front was perpendicular to the radial direction, and the radio emission of the type II burst was in the fundamental frequency. The result is compared to and agrees with coronal magnetic-field models.

Stanislavsky, A. A.; Konovalenko, A. A.; Koval, A. A.; Dorovskyy, V. V.; Zarka, P.; Rucker, H. O.

2015-01-01

356

The Black Cuckoo-Shrike Campephaga flava: A new record for the Mountain Zebra National Park and the Cradock district, Cape Province  

Directory of Open Access Journals (Sweden)

Full Text Available The avifauna of the Mountain Zebra National Park (MZNP has been recorded over a period of some two decades (Skead 1965, Koedoe 8: 1-40; Penzhorn & Bronkhorst 1976, Koedoe 19: 171-174; Penzhorn 1977, Koedoe 20: 205-207; Grobler & Bronkhorst 1981, Koedoe 24: 199-203. Collett (1982 Southern Birds 9: 1-65 has summarised all the available information on the avifauna of the Cradock district assembled since the turn of the century. Although 203 species are recorded from the MZNP by these authors (and a further four in the roneoed checklist for the park (Anon, updated, National Parks Board of Trustees, roneod, 15 pp no mention is made of the Black Cuckoo-Shrike Campephaga flava. Collett (1982 does not list it for the Cradock district.

I.A.W Macdonald

1984-12-01

357

Effects of the Bioaccumulative Polybrominated Diphenyl Ether Flame Retardant Congener BDE-47 on Growth, Development, and Reproductive Success in Zebra Finches.  

Science.gov (United States)

This study investigated the effects of the polybrominated diphenyl ether congener, 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) on the growth and development, and subsequent breeding success of exposed zebra finches (Taeniopygia guttata). Using oral dosing procedures and treatments adjusted by weight, we treated newly hatched chicks daily for the first 20-days-post-hatch (dph) with varying treatments of BDE-47 (0, 5, 50, and 500 ng/g bw/day). Weight and tarsal measurements were monitored from hatch to 90 dph, but no differences were observed between treatment groups at any age. Treated females that reached sexual maturity were mated with untreated males; however, again no treatment effects were observed on breeding success. Analysis of tissue samples at 21 dph did indicate that debromination of BDE-47 had occurred resulting in BDE-28 and BDE-17 metabolites. PMID:25283367

Currier, Heidi A; Letcher, Robert J; Williams, Tony D; Elliott, John E

2015-02-01

358

Evaluation of spatial distribution and accumulation of novel brominated flame retardants, HBCD and PBDEs in an Italian subalpine lake using zebra mussel (Dreissena polymorpha).  

Science.gov (United States)

Because of the reduction in the use of polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD), novel brominated flame retardants (NBFRs), including 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), decabromodiphenyl ethane (DBDPE), hexabromobenzene (HBB), and pentabromoethylbenzene (PBEB), started to be marketed as alternatives to the banned formulations. In this study, the spatial distribution and accumulation of NBFRs, PBDEs, and HBCD in the biota have been investigated in the littoral compartment of a large and deep subalpine lake (Lake Maggiore, Northern Italy), using zebra mussel Dreissena polymorpha and roach (Rutilus rutilus) as bioindicators. To our knowledge, this is the first study reporting the contamination of NBFRs in the freshwater invertebrate D. polymorpha. Contamination of zebra mussel due to PBEB, HBB, and BTBPE was low, ranging from 0.9 to 2.9 ng/g lipid weight, from 1.1 to 2.9 ng/g l.w., and from 3.5 to 9.5 ng/g l.w., respectively. PBEB and BTBPE in roach were always below the detection limit, while the contamination of HBB ranged from < limits of detection (LOD) to 1.74 ng/g l.w., indicating a weak contamination. DBDPE was < LOD in all the considered biological samples. Finally, HBCD was detected in all organic tissues with mean concentrations up to 74.4 ng/g l.w. PBDE results, supported by principal component analysis elaboration, suggested a possible contamination due to the congeners composing the penta- and deca-BDE technical formulations, which are present in the Lake Maggiore basin. The biomagnification factor values showed that tetra- and penta-BDE biomagnified, while octa-, nona-, and deca-BDE were still bioavailable and detectable in the fish muscles, but they do not biomagnified. Considering the other BFRs, only HBCD showed a moderate biomagnification potential. PMID:24756669

Poma, Giulia; Binelli, Andrea; Volta, Pietro; Roscioli, Claudio; Guzzella, Licia

2014-08-01

359

Developmental pattern of diacylglycerol lipase-? (DAGL?) immunoreactivity in brain regions important for song learning and control in the zebra finch (Taeniopygia guttata).  

Science.gov (United States)

Zebra finch song is a learned behavior dependent upon successful progress through a sensitive period of late-postnatal development. This learning is associated with maturation of distinct brain nuclei and the fiber tract interconnections between them. We have previously found remarkably distinct and dense CB1 cannabinoid receptor expression within many of these song control brain regions, implying a normal role for endocannabinoid signaling in vocal learning. Activation of CB1 receptors via daily treatments with exogenous agonist during sensorimotor stages of song learning (but not in adulthood) results in persistent alteration of song patterns. Now we are working to understand physiological changes responsible for this cannabinoid-altered vocal learning. We have found that song-altering developmental treatments are associated with changes in expression of endocannabinoid signaling elements, including CB1 receptors and the principal CNS endogenous agonist, 2-AG. Within CNS, 2-AG is produced largely through activity of the ? isoform of the enzyme diacylglycerol lipase (DAGL?). To better appreciate the role of 2-AG production in normal vocal development we have determined the spatial distribution of DAGL? expression within zebra finch CNS during vocal development. Early during vocal development at 25 days, DAGL? staining is typically light and of fibroid processes. Staining peaks late in the sensorimotor stage of song learning at 75 days and is characterized by fiber, neuropil and some staining of both small and large cell somata. Results provide insight to the normal role for endocannabinoid signaling in the maturation of brain regions responsible for song learning and vocal-motor output, and suggest mechanisms by which exogenous cannabinoid exposure alters acquisition of this form of vocal communication. PMID:24140814

Soderstrom, Ken; Wilson, Ashley R

2013-11-01

360

Corticosterone exposure during development has sustained but not lifelong effects on body size and total and free corticosterone responses in the zebra finch.  

Science.gov (United States)

Animals exposed to stress during development experience sustained morphological, physiological, neurological, and behavioral consequences. For example, elevated glucocorticoids (GCs) during development can increase GC secretion in adults. Studies have examined the sustained effects of elevated developmental GCs on total GC responses, but no study to date has examined the effect of developmental stress on corticosteroid binding globulin (CBG). CBG is a protein which binds to GCs and facilitates their transportation in blood. When bound to CBG, GCs are unavailable to interact with target tissues. Exposure to stress can decrease CBG capacity and, thus, increase free GCs (the portion of unbound GCs). We examined the long-term effects of elevated corticosterone (CORT) during development (12-28days post-hatch) on acute stress responses, negative feedback, and CBG capacity at 30, 60, and 90days post-hatch in zebra finches. Additionally, we evaluated the effect of CORT treatment on body size and condition at 28, 60, and 90days post-hatch. CORT exposed birds had higher acute stress responses at 30days post-hatch compared to control birds. However, there was no treatment effect at 60 or 90days post-hatch. CBG levels were not affected by treatment, and so free CORT estimations reflected patterns in total CORT. CORT treatment decreased growth and condition in zebra finches at 28days post-hatch, but these differences were not present at later life history stages. However, brood size had a sustained effect on body size such that birds reared in medium sized broods were larger at 28, 60, and 90days post-hatch. These results demonstrate the complexity of early environmental effects on adult phenotype and suggest that some conditions may have stronger programmatic effects than others. PMID:24188885

Crino, O L; Driscoll, Stephanie C; Breuner, C W

2014-01-15

361

Functional genomic analysis and neuroanatomical localization of miR-2954, a song-responsive sex-linked microRNA in the zebra finch.  

Science.gov (United States)

Natural experience can cause complex changes in gene expression in brain centers for cognition and perception, but the mechanisms that link perceptual experience and neurogenomic regulation are not understood. MicroRNAs (miRNAs or miRs) have the potential to regulate large gene expression networks, and a previous study showed that a natural perceptual stimulus (hearing the sound of birdsong in zebra finches) triggers rapid changes in expression of several miRs in the auditory forebrain. Here we evaluate the functional potential of one of these, miR-2954, which has been found so far only in birds and is encoded on the Z sex chromosome. Using fluorescence in situ hybridization and immunohistochemistry, we show that miR-2954 is present in subsets of cells in the sexually dimorphic brain regions involved in song production and perception, with notable enrichment in cell nuclei. We then probe its regulatory function by inhibiting its expression in a zebra finch cell line (G266) and measuring effects on endogenous gene expression using Illumina RNA sequencing (RNA-seq). Approximately 1000 different mRNAs change in expression by 1.5-fold or more (adjusted p < 0.01), with increases in some but not all of the targets that had been predicted by Targetscan. The population of RNAs that increase after miR-2954 inhibition is notably enriched for ones involved in the MAP Kinase (MAPK) pathway, whereas the decreasing population is dominated by genes involved in ribosomes and mitochondrial function. Since song stimulation itself triggers a decrease in miR-2954 expression followed by a delayed decrease in genes encoding ribosomal and mitochondrial functions, we suggest that miR-2954 may mediate some of the neurogenomic effects of song habituation. PMID:25565940

Lin, Ya-Chi; Balakrishnan, Christopher N; Clayton, David F

2014-01-01

362

Discovery of a novel functional leptin protein (LEP) in zebra finches: evidence for the existence of an authentic avian leptin gene predominantly expressed in the brain and pituitary.  

Science.gov (United States)

Leptin (LEP) is reported to play important roles in controlling energy balance in vertebrates, including birds. However, it remains an open question whether an authentic "LEP gene" exists and functions in birds. Here, we identified and characterized a LEP gene (zebra finch LEP [zbLEP]) encoding a 172-amino acid precursor in zebra finches. Despite zbLEP showing limited amino acid sequence identity (26%-29%) to human and mouse LEPs, synteny analysis proved that zbLEP is orthologous to mammalian LEP. Using a pAH32 luciferase reporter system and Western blot analysis, we demonstrated that the recombinant zbLEP protein could potently activate finch and chicken LEP receptors (zbLEPR; cLEPR) expressed in human embryonic kidney 293 cells and enhance signal transducer and activator of transcription 3 phosphorylation, further indicating that zbLEP is a functional ligand for avian LEPRs. Interestingly, quantitative real-time RT-PCR revealed that zbLEP mRNA is expressed nearly exclusively in the pituitary and various brain regions but undetectable in adipose tissue and liver, whereas zbLEPR mRNA is widely expressed in adult finch tissues examined with abundant expression noted in pituitary, implying that unlike mammalian LEP, finch LEP may not act as an adipocyte-derived signal to control energy balance. As in finches, a LEP highly homologous to zbLEP was also identified in budgerigar genome. Strikingly, finch and budgerigar LEPs show little homology with chicken LEP (cLEP) previously reported, suggesting that the so-called cLEP is incorrect. Collectively, our data provide convincing evidence for the existence of an authentic functional LEP in avian species and suggest an important role of brain- and pituitary-derived LEP played in vertebrates. PMID:24823393

Huang, Guian; Li, Juan; Wang, Hongning; Lan, Xinyu; Wang, Yajun

2014-09-01

363

Transmission efficiency of 'Candidatus Liberibacter solanacearum' and potato zebra chip disease progress in relation to pathogen titer, vector numbers, and feeding sites.  

Science.gov (United States)

ABSTRACT With diseases caused by vector-borne plant pathogens, acquisition and inoculation are two primary stages of the transmission, which can determine vector efficiency in spreading the pathogen. The present study was initiated to quantify acquisition and inoculation successes of 'Candidatus Liberibacter solanacearum', the etiological agent of zebra chip disease of potato, by its psyllid vector, Bactericera cockerelli (Hemiptera: Triozidae). Acquisition success was evaluated in relation to feeding site on the host plant as well as the acquisition access period. Inoculation success was evaluated in relation to vector number (1 and 4) on the plants. Acquisition success was influenced by the feeding site on the plant. The highest acquisition success occurred when insects had access to the whole plant. The results of the inoculation study indicated that the rate of successfully inoculated plants increased with the vector number. Plants inoculated with multiple psyllids had higher bacterial titer at the point of inoculation. Although disease incubation period was significantly shorter in plants inoculated with multiple psyllids, this effect was heterogeneous across experimental blocks, and was independent of pathogen quantity detected in the leaflets 3 days postinoculation. Disease progress was not affected by bacterial quantity injected or psyllid numbers. PMID:22784252

Rashed, A; Nash, T D; Paetzold, L; Workneh, F; Rush, C M

2012-11-01

364

Vector transmission efficiency of liberibacter by Bactericera cockerelli (Hemiptera: Triozidae) in zebra chip potato disease: effects of psyllid life stage and inoculation access period.  

Science.gov (United States)

Successful transmission of plant pathogens by insects depends on the vector inoculation efficiency and how rapidly the insect can effectively transmit the pathogen to the host plant. The potato psyllid, Bactericera cockerelli (Sulc), has recently been found to transmit "Candidatus Liberibacter solanacearum," a bacterium associated with zebra chip (ZC), an emerging and economically important disease of potato in several parts of the world. Currently, little is known about the epidemiology of ZC and its vector's inoculation capabilities. Studies were conducted in the field and laboratory to 1) assess transmission efficiency of potato psyllid nymphs and adults; 2) determine whether psyllid inoculation access period affects ZC incidence, severity, and potato yield; and 3) determine how fast the psyllid can transmit liberibacter to potato, leading to ZC development. Results showed that adult potato psyllids were highly efficient vectors of liberibacter that causes ZC and that nymphs were less efficient than adults at transmitting this bacterium. It was also determined that inoculation access period had little influence on overall ZC disease incidence, severity, and resulting yield loss. Moreover, results showed that exposure of a plant to 20 adult potato psyllids for a period as short as 1 h resulted in ZC symptom development. Furthermore, it was shown that a single adult potato psyllid was capable of inoculating liberibacter to potato within a period as short as 6 h, thereby inducing development of ZC. This information will help in developing effective management strategies for this serious potato disease. PMID:22066176

Buchman, Jeremy L; Sengoda, Venkatesan G; Munyaneza, Joseph E

2011-10-01

365

Developmental but not adult cannabinoid treatments persistently alter axonal and dendritic morphology within brain regions important for zebra finch vocal learning.  

Science.gov (United States)

Prior work shows developmental cannabinoid exposure alters zebra finch vocal development in a manner associated with altered CNS physiology, including changes in patterns of CB1 receptor immunoreactivity, endocannabinoid concentrations and dendritic spine densities. These results raise questions about the selectivity of developmental cannabinoid effects: are they a consequence of a generalized developmental disruption, or are effects produced through more selective and distinct interactions with biochemical pathways that control receptor, endogenous ligand and dendritic spine dynamics? To begin to address this question we have examined effects of developmental cannabinoid exposure on the pattern and density of expression of proteins critical to dendritic (MAP2) and axonal (Nf-200) structure to determine the extent to which dendritic vs. axonal neuronal morphology may be altered. Results demonstrate developmental, but not adult cannabinoid treatments produce generalized changes in expression of both dendritic and axonal cytoskeletal proteins within brain regions and cells known to express CB1 cannabinoid receptors. Results clearly demonstrate that cannabinoid exposure during a period of sensorimotor development, but not adulthood, produce profound effects upon both dendritic and axonal morphology that persist through at least early adulthood. These findings suggest an ability of exogenous cannabinoids to alter general processes responsible for normal brain development. Results also further implicate the importance of endocannabinoid signaling to peri-pubertal periods of adolescence, and underscore potential consequences of cannabinoid abuse during periods of late-postnatal CNS development. PMID:24594017

Gilbert, Marcoita T; Soderstrom, Ken

2014-04-16

366

Mutagenesis study on the zebra fish SOX9 high-mobility group: comparison of sequence and non-sequence specific HMG domains.  

Science.gov (United States)

A unique class of proteins, containing high-mobility group (HMG) domain(s), recognizes unusual DNA structures and/or bends specific to AT-rich linear double-stranded DNA. The DNA binding feature of these proteins is exhibited in the HMG domain(s). Although the sequence specific and non-sequence specific HMG domains exhibit very high degrees of sequence similarity, the reasons for the difference between their DNA recognition mechanisms are unclear. A series of zebra fish SOX9 HMG domain mutants was prepared in an effort to elucidate the importance of various residues on protein stability and DNA binding. This study is the first of a comprehensive mutagenesis study on a sequence specific HMG domain. Comparing how various residues influence sequence specific and non-sequence specific HMG domains helps us to rationalize their mode of action. Positively charged amino acids concentrated at the surface of sequence specific HMG domains recognize specific, linear AT-rich DNA segments. After the negative charges at the surface of the DNA are neutralized, the hydrophobic residues of the protein may intercalate DNA. Phenylalanine at position 12 plays a crucial role in the sequence specific HMG domain. The differences in pI values, the instability index, and DNA contact regions between sequence and non-sequence specific HMG domains are associated with their functional modes. PMID:14503868

Hsiao, Nai-Wan; Samuel, Dharmaraj; Liu, Yu-Nan; Chen, Li-Chuan; Yang, Tzu-Ying; Jayaraman, Gurunathan; Lyu, Ping-Chiang

2003-09-30

367

First Analysis of Radiative Properties of Moderate-atomic-number Planar Wire Arrays on Zebra at UNR at Higher Current of 1.7 MA*  

Science.gov (United States)

The analysis of implosions of Cu and Ag planar wire array (PWA) loads recently performed at the enhanced 1.7 MA Zebra generator at UNR is presented. Experiments were performed with a Load Current Multiplier with a 1cm anode-cathode gap (twice shorter than in a standard 1 MA mode). A full diagnostic set included more than ten different beam-lines with the major focus on time-gated and time-integrated x-ray imaging and spectra, total radiation yields, and fast, filtered x-ray detector data. In particular, the experimental results for a double PWA load consisting of twelve 10?m Cu wires in each row (total mass M ˜ 175 ?g) and a much heavier single PWA load consisting of ten 30?m Ag wires (M ˜ 750 ?g) were analyzed using a set of theoretical codes. The effects of both a decreased a-c gap and an increased current on radiative properties of these loads are discussed. * This work was supported by NNSA/DOE Coop. Agr. DE-FC52-06NA27588, 27586, and 27616. Sandia is a multi-program laboratory operated by Sandia Co., a LMC, for the US DOE under Contract DE-AC04-94AL85000.

Safronova, A. S.; Kantsyrev, V. L.; Esaulov, A. A.; Astanovitskiy, A.; Legalloudec, B.; Presura, R.; Shrestha, I.; Williamson, K. M.; Shlyaptseva, V.; Weller, M. E.; Ouart, N. D.; Keim, S. F.; Osborne, G. C.; Chuvatin, A. S.; Coverdale, C. A.

2010-11-01

368

First analysis of radiative properties of moderate-atomic-number planar wire arrays on Zebra at UNR at higher current of 1.7 MA.  

Energy Technology Data Exchange (ETDEWEB)

The analysis of implosions of Cu and Ag planar wire array (PWA) loads recently performed at the enhanced 1.7 MA Zebra generator at UNR is presented. Experiments were performed with a Load Current Multiplier with a 1cm anode-cathode gap (twice shorter than in a standard 1 MA mode). A full diagnostic set included more than ten different beam-lines with the major focus on time-gated and time-integrated x-ray imaging and spectra, total radiation yields, and fast, filtered x-ray detector data. In particular, the experimental results for a double PWA load consisting of twelve 10 {micro}m Cu wires in each row (total mass M {approx} 175 {micro}g) and a much heavier single PWA load consisting of ten 30 {micro}m Ag wires (M {approx} 750 {micro}g) were analyzed using a set of theoretical codes. The effects of both a decreased a-c gap and an increased current on radiative properties of these loads are discussed.

Keim, S. F. (University of Nevada, Reno, NV); Chuvatin, Alexander S. (Ecole Polytechnique, Palaiseau, France); Osborne, Glenn C. (University of Nevada, Reno, NV); Esaulov, Andrey A. (University of Nevada, Reno, NV); Presura, R. (University of Nevada, Reno, NV); Shrestha, I. (University of Nevada, Reno, NV); Kantsyrev, Victor Leonidovich (University of Nevada, Reno, NV); Shlyaptseva, V. (University of Nevada, Reno, NV); Coverdale, Christine Anne; Williamson, K. M. (University of Nevada, Reno, NV); Ouart, Nicholas D. (University of Nevada, Reno, NV); Astanovitsky, A. L. (University of Nevada, Reno, NV); Weller, M. E. (University of Nevada, Reno, NV); Safronova, Alla S. (University of Nevada, Reno, NV); LeGalloudec, B. (University of Nevada, Reno, NV)

2010-11-01

369

Linking Species Traits to the Abiotic Template of Flowing Waters: Contrasting Eco physiologies Underlie Displacement of Zebra Mussels by Quagga Mussels in a Large River-Estuary  

Science.gov (United States)

The St. Lawrence River-Estuary was the gateway of entry for dreissenids to North America and holds some of the oldest populations. The St. Lawrence also has four distinct physical-chemical water masses (a regional scale abiotic template) that both species inhabit. Despite their ecological similarities, quagga mussels are supplanting zebra mussels in much of their shared range. In order to try to better understand the changing distributions of these two species we compared glycogen, shell mass and tissue biomass in each of the water masses. This comparative physiological combined with experimental approaches (estuarine salinity experiments and reciprocal transplants) showed that while quagga mussels should dominate in most habitats, that abiotic/bioenergetic constraints in two regions (the Ottawa River plume and the freshwater-marine transition zone) might prevent them from dominating these locations. These findings are an example of how the interaction of landscape scale abiotic heterogeneity and a species-specific physiology can have strong impacts of distribution of biota large rivers.

Casper, A. F.

2005-05-01

370

Evidence for cholinergic participation in the control of bird song; acetylcholinesterase distribution and muscarinic receptor autoradiography in the zebra finch brain  

Energy Technology Data Exchange (ETDEWEB)

Brain regions thought to be involved in the control of song in the zebra finch (Poephila guttata), were examined histochemically using the Karnovsky and Roots direct-coloring method for the detection of acetylcholinesterase (AChE) and the autoradiographic method for the localization of muscarinic cholinergic receptors following injection of tritiated quinuclidinyl benzilate (3H QNB). All presently identified vocal control nuclei in both males and females contain AChE. These nuclei include Area X, magnocellular nucleus of the anterior neostriatum (MAN), nucleus interface (NIF), caudal nucleus of the hyperstriatum ventrale (HVc), intercollicular nucleus (ICo), nucleus uva, robust nucleus of the archistriatum (RA), and tracheosyringeal portion of the hypoglossal nerve nucleus (nXIIts). All nuclei except Area X contain mostly AChE-synthesizing cell bodies. All of these nuclei contain some AChE in the neuropil, with particularly intense staining in Area X, the surrounding LPO, and the dorsomedial portion of ICo. In agreement with this description are very high concentrations of 3H QNB in both Area X and the dorsomedial ICo. HVc also appears specifically labeled. Evidence from these two histological technique suggests that efferent projections of most vocal control area may utilize acetylcholine, and that several of the vocal control nuclei may themselves receive muscarinic cholinergic projection. In Area X, there are sex differences of AChE neuropil staining. This evidence suggesting that sexually dimorphic projections to or within Area X are cholinergic or cholinoceptive.

Ryan, S.M.; Arnold, A.P.

1981-10-20

371

Daily behaviour can differ between colour morphs of the same species: a study on circadian activity behaviour of grey and pied zebra finches.  

Science.gov (United States)

To investigate if the plumage colour mutation relates to circadian activity behaviour in the zebra finch, Taeniopygia guttata, wild type grey and pied mutant males were sequentially subjected for three weeks each to 12 h light:12 h darkness (12L:12D) and constant dim light (LL(dim)) condition. During the first 3 h of the 12 h day, pied finches were significantly greater active than grey finches. Also, as compared to grey, pied finches had longer activity duration in the day, with early activity onsets and late activity offsets. This was changed under free-running condition (LL(dim)), when the activity later in the subjective day (clock hour 9 and 11) was significantly greater in grey than in pied finches.Two colour morphs differed in daily activity profile, but not in the total daily activity or circadian rhythm period. Results suggest that greyzebra finches represent late chronotype, and could perhaps be better adapted to a seemingly stressful environment, such as low intensity LL(dim) in the present study. PMID:24851415

Mishra, Ila; Trivedi, Amit Kumar; Kumar, Vinod

2014-05-01

372

Molecular and physiological properties associated with zebra complex disease in potatoes and its relation with Candidatus Liberibacter contents in psyllid vectors.  

Science.gov (United States)

Zebra complex (ZC) disease on potatoes is associated with Candidatus Liberibacter solanacearum (CLs), an ?-proteobacterium that resides in the plant phloem and is transmitted by the potato psyllid Bactericera cockerelli (Šulc). The name ZC originates from the brown striping in fried chips of infected tubers, but the whole plants also exhibit a variety of morphological features and symptoms for which the physiological or molecular basis are not understood. We determined that compared to healthy plants, stems of ZC-plants accumulate starch and more than three-fold total protein, including gene expression regulatory factors (e.g. cyclophilin) and tuber storage proteins (e.g., patatins), indicating that ZC-affected stems are reprogrammed to exhibit tuber-like physiological properties. Furthermore, the total phenolic content in ZC potato stems was elevated two-fold, and amounts of polyphenol oxidase enzyme were also high, both serving to explain the ZC-hallmark rapid brown discoloration of air-exposed damaged tissue. Newly developed quantitative and/or conventional PCR demonstrated that the percentage of psyllids in laboratory colonies containing detectable levels of CLs and its titer could fluctuate over time with effects on colony prolificacy, but presumed reproduction-associated primary endosymbiont levels remained stable. Potato plants exposed in the laboratory to psyllid populations with relatively low-CLs content survived while exposure of plants to high-CLs psyllids rapidly culminated in a lethal collapse. In conclusion, we identified plant physiological biomarkers associated with the presence of ZC and/or CLs in the vegetative potato plant tissue and determined that the titer of CLs in the psyllid population directly affects the rate of disease development in plants. PMID:22615987

Alvarado, Veria Y; Odokonyero, Denis; Duncan, Olivia; Mirkov, T Erik; Scholthof, Herman B

2012-01-01

373

Effects of liberibacter-infective Bactericera cockerelli (Hemiptera: Triozidae) density on zebra chip potato disease incidence, potato yield, and tuber processing quality.  

Science.gov (United States)

In plant pathosystems involving insect vectors, disease spread, incidence, and severity often depend on the density of the vector population and its rate of infectivity with the disease pathogen. The potato psyllid, Bactericera cockerelli (Sulc), has recently been associated with zebra chip (ZC), an emerging and economically important disease of potato in the United States, Mexico, Central America, and New Zealand. "Candidatus Liberibacter solanacearum," a previously undescribed species of liberibacter has been linked to the disease and is transmitted to potato by B. cockerelli. Experiments were conducted under laboratory and field conditions to determine the impact of B. cockerelli density on ZC incidence, potato yield, and tuber processing quality. Insect densities ranging from one to 25 liberibacter-infective psyllids per plant were used during the experiments. Results showed that a single adult potato psyllid was capable of inoculating liberibacter to potato and causing ZC disease after a 72-h inoculation access period and was as damaging as 25 psyllids per plant. In addition, ZC-diseased plants showed a sharp reduction in tuber yield but the disease response was independent of the density of psyllids. Furthermore, both glucose and sucrose were found to have highly elevated concentrations in ZC-diseased potato tubers compared with noninfected ones and psyllid density did not vary the response. The high reducing sugar concentrations found in ZC-infected potato tubers are believed to be responsible for browning and reduced quality in processed ZC-infected tubers. This information could help ZC-affected potato producers in making effective management decisions for this serious disease. PMID:22299337

Buchman, Jeremy L; Heilman, Blaine E; Munyaneza, Joseph E

2011-12-01

374

Plasma reactive oxygen metabolites and non-enzymatic antioxidant capacity are not affected by an acute increase of metabolic rate in zebra finches.  

Science.gov (United States)

Understanding the sources of variation in oxidative stress level is a challenging issue due to the implications of oxidative stress for late age diseases, longevity and life-history trade-offs. Reactive oxygen species that cause oxidative stress are mostly a by-product of energy metabolism and it is therefore often assumed that oxidative stress is proportional to energy consumption. In mammals, an increased metabolic rate induced by cold exposure generally increases oxidative stress. However, compared to mammals, birds generate fewer free radicals per ATP produced and hence it is not obvious that, in birds, a cold-induced increase of metabolic rate increase oxidative stress. We tested whether cold-induced increase in metabolic rate increased oxidative stress in zebra finches by exposing individuals to cold and warm overnight temperatures. We registered metabolic rate and plasma levels of non-enzymatic antioxidants and reactive oxygen metabolites (ROMs), a measure of oxidative damage. Metabolic rate was on average 88 % higher in cold compared to warm temperature, with females being stronger affected than males. However, temperature had no effect on plasma antioxidants or our measure of oxidative damage. Middle-age birds had higher levels of plasma antioxidants than younger and older birds, but age was unrelated to ROMs. Birds showed repeatability of plasma ROMs across temperatures but not of non-enzymatic antioxidants. In contrast to similar studies in mammals, our results do not show evidence of increased oxidative stress in plasma after an acute cold-induced increase of metabolic rate but research in more bird species is needed to assess the generality of this pattern. PMID:23358864

Beamonte-Barrientos, Rene; Verhulst, Simon

2013-07-01

375

Song tutoring in presinging zebra finch juveniles biases a small population of higher-order song-selective neurons toward the tutor song.  

Science.gov (United States)

We explored physiological changes correlated with song tutoring by recording the responses of caudal nidopallium neurons of zebra finches aged P21-P24 (days post hatching) to a broad spectrum of natural and synthetic stimuli. Those birds raised with their fathers tended to show behavioral evidence of song memorization but not of singing; thus auditory responses were not confounded by the birds' own vocalizations. In study 1, 37 of 158 neurons (23%) in 17 of 22 tutored and untutored birds were selective for only 1 of 10 stimuli comprising broadband signals, early juvenile songs and calls, female calls, and adult songs. Approximately 30% of the selective neurons (12/37 neurons in 9 birds) were selective for adult conspecific songs. All these were found in the song system nuclei HVC and paraHVC. Of 122 neurons (17 birds) in tutored birds, all of the conspecific song-selective neurons (8 neurons in 6 birds) were selective for the adult tutor song; none was selective for unfamiliar song. In study 2 with a different sampling strategy, we found that 11 of 12 song-selective neurons in 6 of 7 birds preferred the tutor song; none preferred unfamiliar or familiar conspecific songs. Most of these neurons were found in caudal lateral nidopallium (NCL) below HVC. Thus by the time a bird begins to sing, there are small numbers of tutor song-selective neurons distributed in several forebrain regions. We hypothesize that a small population of higher-order auditory neurons is innately selective for complex features of behaviorally relevant stimuli and these responses are modified by specific perceptual/social experience during development. PMID:22786956

Adret, Patrice; Meliza, C Daniel; Margoliash, Daniel

2012-10-01

376

Circulating breeding and pre-breeding prolactin and LH are not associated with clutch size in the zebra finch (Taeniopygia guttata).  

Science.gov (United States)

Clutch size is a fundamental predictor of avian fitness, widely-studied from evolutionary and ecological perspectives, but surprisingly little is known about the physiological mechanisms regulating clutch size variation. The only formal mechanistic hypothesis for avian clutch-size determination predicts an anti-gonadal effect of circulating prolactin (PRL) via the inhibition of luteinizing hormone (LH), and has become widely-accepted despite little experimental support. Here we investigated the relationship between pre-breeding and breeding plasma PRL and LH and clutch-size in captive-breeding female zebra finches (Taeniopygia guttata). Using a repeated-measures design, we followed individual females from pre-breeding, through multiple breeding attempts, and attempted to decrease PRL using the D2-receptor agonist, bromocriptine. Clutch size was independent of variation in pre-breeding PRL or LH, although pre-breeding LH was negatively correlated with the time between pairing and the onset of laying. Clutch size was independent of variation in plasma PRL on all days of egg-laying. Bromocriptine treatment had no effect on plasma PRL, but in this breeding attempt clutch size was also independent of plasma PRL. Finally, we found no evidence for an inverse relationship between plasma PRL and LH levels, as predicted if PRL had inhibitory effects via LH. Thus, our data fail to provide any support for the involvement of circulating PRL in clutch size determination. These findings suggest that alternative models for hormonal control of avian clutch size need to be considered, perhaps involving downstream regulation of plasma PRL at the level of the ovary, or other hormones that have not been considered to date. PMID:24768674

Ryan, Calen P; Dawson, Alistair; Sharp, Peter J; Meddle, Simone L; Williams, Tony D

2014-06-01

377

Vigilance behaviour and its endocrine correlates in Plains zebra (Equus burchelli) living in a predator-free landscape  

OpenAIRE

Group size affects individual and collective vigilance levels of prey species. As individual vigilance decreases with increasing group size, the indirect risk of predation to each individual and the group as a whole will also decrease (dilution and many-eyes effect) which may have a decreasing effect on stress responses on group level as well. Where predation risk is low, other factors like group size might influence stress-related glucocorticoid output in prey species. I test the rela...

Fourie, Clasina Elizabeth

2012-01-01

378

Comparison of acute toxicity of process chemicals used in the oil refinery industry, tested with the diatom Chaetoceros gracilis, the flagellate Isochrysis galbana, and the zebra fish, Brachydanio rerio  

Energy Technology Data Exchange (ETDEWEB)

Chemicals under the trade names Nalco 537-DA, Nalco 625, Nalco 7607, Nalco 5165, Ivamin, and technical monoethanolamine are used extensively in the oil refinery industry. Aquatic toxicity tests were conducted using zebra fish fry (Brachydanio rerio) and the unicellular algae Isochrysis galbana (a flagellate) and Chaetoceros gracilis (a diatom). Inhibition of cell division, chlorophyll content, and {sup 14}CO{sub 2} uptake in the algae were sensitive end points. The effective concentrations (EC50s) of growth inhibition were 0.1 mg/L (Ivamin; I. galbana), 0.8 mg/L (Nalco 7607; I. galbana), 6 mg/L (Nalco 625; I. galbana), 10 mg/L (Nalco 5165; C. gracilis), and 15 mg/L (Nalco 537-DA; C. gracilis). The lethal concentrations (LC50s) (96 h) toward zebra fish fry was 1 mg/L for Nalco 7607, 6.5 mg/L for Nalco 537-DA, 7.1 mg/L for Nalco 625, and 20 mg/L for Ivamin 803. Monoethanolamine had an LC50 higher than 5,000 mg/L. Nalco 5165 was not tested on fish fry. The heartbeat frequency of fish embryos was reduced by 2.5 mg/L Nalco 537-DA, but this was an insensitive end point for the other chemicals.

Roseth, S.; Edvardsson, T.; Botten, T.M.; Fuglestad, J.; Fonnum, F.; Stenersen, J. [Univ. of Oslo (Norway)

1996-07-01

379

Comparison of acute toxicity of process chemicals used in the oil refinery industry, tested with the diatom Chaetoceros gracilis, the flagellate Isochrysis galbana, and the zebra fish, Brachydanio rerio  

International Nuclear Information System (INIS)

Chemicals under the trade names Nalco 537-DA, Nalco 625, Nalco 7607, Nalco 5165, Ivamin, and technical monoethanolamine are used extensively in the oil refinery industry. Aquatic toxicity tests were conducted using zebra fish fry (Brachydanio rerio) and the unicellular algae Isochrysis galbana (a flagellate) and Chaetoceros gracilis (a diatom). Inhibition of cell division, chlorophyll content, and 14CO2 uptake in the algae were sensitive end points. The effective concentrations (EC50s) of growth inhibition were 0.1 mg/L (Ivamin; I. galbana), 0.8 mg/L (Nalco 7607; I. galbana), 6 mg/L (Nalco 625; I. galbana), 10 mg/L (Nalco 5165; C. gracilis), and 15 mg/L (Nalco 537-DA; C. gracilis). The lethal concentrations (LC50s) (96 h) toward zebra fish fry was 1 mg/L for Nalco 7607, 6.5 mg/L for Nalco 537-DA, 7.1 mg/L for Nalco 625, and 20 mg/L for Ivamin 803. Monoethanolamine had an LC50 higher than 5,000 mg/L. Nalco 5165 was not tested on fish fry. The heartbeat frequency of fish embryos was reduced by 2.5 mg/L Nalco 537-DA, but this was an insensitive end point for the other chemicals

380

Gonadotropin releasing hormone (GnRH) and gonadotropin inhibitory hormone (GnIH) in the songbird hippocampus: regional and sex differences in adult zebra finches.  

Science.gov (United States)

Hypothalamic gonadotropin releasing hormone (GnRH) and gonadotropin inhibitory hormone (GnIH) are vital to reproduction in all vertebrates. These neuropeptides are also present outside of the hypothalamus, but the roles of extra-hypothalamic GnRH and GnIH remain enigmatic and widely underappreciated. We used immunohistochemistry and PCR to examine whether multiple forms of GnRH (chicken GnRH-I (GnRH1), chicken GnRH-II (GnRH2) and lamprey GnRH-III (GnRH4)) and GnIH are present in the hippocampus (Hp) of adult zebra finches (Taeniopygia guttata). Using immunohistochemistry, we provide evidence that GnRH1, GnRH2 and GnRH4 are present in hippocampal cell bodies and/or fibers and that GnIH is present in hippocampal fibers only. There are regional differences in hippocampal GnRH immunoreactivity, and these vary across the different forms of GnRH. There are also sex differences in hippocampal GnRH immunoreactivity, with generally more GnRH1 and GnRH2 in the female Hp. In addition, we used PCR to examine the presence of GnRH1 mRNA and GnIH mRNA in micropunches of Hp. PCR and subsequent product sequencing demonstrated the presence of GnRH1 mRNA and the absence of GnIH mRNA in the Hp, consistent with the pattern of immunohistochemical results. To our knowledge, this is the first study in any species to systematically examine multiple forms of GnRH in the Hp or to quantify sex or regional differences in hippocampal GnRH. Moreover, this is the first demonstration of GnIH in the avian Hp. These data shed light on an important issue: the sites of action and possible functions of GnRH and GnIH outside of the HPG axis. PMID:23727031

McGuire, Nicolette; Ferris, Jennifer K; Arckens, Lutgarde; Bentley, George E; Soma, Kiran K

2013-08-01

381

Poly(N-isopropylacrylamide)-coated thermo-responsive nanoparticles for controlled delivery of sulfonated Zn-phthalocyanine in Chinese hamster ovary cells in vitro and zebra fish in vivo  

Science.gov (United States)

Poly(N-isopropylacrylamide) (PNIPAM)-coated Fe3O4@SiO2@CdTe multifunctional nanoparticles with photoluminescent (PL), thermosensitive and magnetic properties, were investigated as carriers to deliver water-soluble, fluorescent sulfonated Zn-phthalocyanine (ZnPcS), a photosensitizing drug for photodynamic therapy of cancer, in Chinese hamster ovary (CHO) cells in vitro and zebra fish in vivo. PNIPAM is a well-known thermo-responsive polymer with a volume phase transition temperature. This property allows it to be swollen in water at temperatures lower than 32-34 °C to take up ZnPcS and shrunken to expel the drug at higher temperatures. Since the PL band of CdTe quantum dots (QDs) as indicators for the nanoparticles is at 585 nm and the emission band of ZnPcS is at 680 nm, it is possible to study the temperature-dependent release of ZnPcS from the nanoparticles by fluorescence measurements. ZnPcS was embedded in the PNIPAM of the nanoparticles at 25 °C in phosphate buffered saline (PBS) solution and released at 37 °C, measured with a spectrophotometer. When CHO cells had been incubated with the ZnPcS-loaded nanoparticles at 27 °C, a similar intracellular localization pattern of CdTe QDs and ZnPcS was seen by multichannel measurements in confocal laser scanning microscopy (CLSM), but a diffuse pattern of only ZnPcS fluorescence was detected in the cytoplasm of the cells at 37 °C, indicating a release of ZnPcS from the nanoparticles. Similar results were also found in the intestinal tract of zebra fish in vivo after intake of the nanoparticles. Since the nanoparticles contain magnetic (Fe3O4) material, the nanoparticles could also be manipulated to change their location in the intestinal tract of the zebra fish with an external magnetic field gradient of 300 G mm-1. The results presented suggest that such multifunctional nanoparticles may have combined potential for temperature-dependent drug delivery, QD photodetection and magnetic manipulation in diagnosis and therapy of diseases.

He, Jia; Chen, Ji-Yao; Wang, Pu; Wang, Pei-Nan; Guo, Jia; Yang, Wu-Li; Wang, Chang-Chun; Peng, Qian

2007-10-01

382

Poly(N-isopropylacrylamide)-coated thermo-responsive nanoparticles for controlled delivery of sulfonated Zn-phthalocyanine in Chinese hamster ovary cells in vitro and zebra fish in vivo  

Energy Technology Data Exchange (ETDEWEB)

Poly(N-isopropylacrylamide) (PNIPAM)-coated Fe{sub 3}O{sub 4} - SiO{sub 2} - CdTe multifunctional nanoparticles with photoluminescent (PL), thermosensitive and magnetic properties, were investigated as carriers to deliver water-soluble, fluorescent sulfonated Zn-phthalocyanine (ZnPcS), a photosensitizing drug for photodynamic therapy of cancer, in Chinese hamster ovary (CHO) cells in vitro and zebra fish in vivo. PNIPAM is a well-known thermo-responsive polymer with a volume phase transition temperature. This property allows it to be swollen in water at temperatures lower than 32-34 deg. C to take up ZnPcS and shrunken to expel the drug at higher temperatures. Since the PL band of CdTe quantum dots (QDs) as indicators for the nanoparticles is at 585 nm and the emission band of ZnPcS is at 680 nm, it is possible to study the temperature-dependent release of ZnPcS from the nanoparticles by fluorescence measurements. ZnPcS was embedded in the PNIPAM of the nanoparticles at 25 deg. C in phosphate buffered saline (PBS) solution and released at 37 deg. C, measured with a spectrophotometer. When CHO cells had been incubated with the ZnPcS-loaded nanoparticles at 27 deg. C, a similar intracellular localization pattern of CdTe QDs and ZnPcS was seen by multichannel measurements in confocal laser scanning microscopy (CLSM), but a diffuse pattern of only ZnPcS fluorescence was detected in the cytoplasm of the cells at 37 deg. C, indicating a release of ZnPcS from the nanoparticles. Similar results were also found in the intestinal tract of zebra fish in vivo after intake of the nanoparticles. Since the nanoparticles contain magnetic (Fe{sub 3}O{sub 4}) material, the nanoparticles could also be manipulated to change their location in the intestinal tract of the zebra fish with an external magnetic field gradient of 300 G mm{sup -1}. The results presented suggest that such multifunctional nanoparticles may have combined potential for temperature-dependent drug delivery, QD photodetection and magnetic manipulation in diagnosis and therapy of diseases.

He Jia [Surface Physics Laboratory (National Key Laboratory) and Department of Physics, Fudan University, Shanghai (China); Chen Jiyao [Surface Physics Laboratory (National Key Laboratory) and Department of Physics, Fudan University, Shanghai (China); Wang Pu [Surface Physics Laboratory (National Key Laboratory) and Department of Physics, Fudan University, Shanghai (China); Wang Peinan [State Key Laboratory for Advanced Photonic Materials and Devices, Fudan University, Shanghai (China); Guo Jia [Department of Macromolecular Science and Key Laboratory of Molecular Engineering of Polymers, Fudan University, Shanghai (China); Yang Wuli [Department of Macromolecular Science and Key Laboratory of Molecular Engineering of Polymers, Fudan University, Shanghai (China); Wang Changchun [Department of Macromolecular Science and Key Laboratory of Molecular Engineering of Polymers, Fudan University, Shanghai (China); Peng Qian [State Key Laboratory for Advanced Photonic Materials and Devices, Fudan University, Shanghai (China)

2007-10-17

383

Elementos traza detectados por plasma inductivamente acoplado (ICP) en pepitonas, Arca zebra (Mollusca, Arcidae) de dos localidades costeras del estado Sucre, Venezuela / Trace elements detected by Inductively Coupled Plasma (ICP) in Turkey wing, Arca zebra (Mollusca, Arcidae) from two coastal locations of Sucre State, Venezuela  

Scientific Electronic Library Online (English)

Full Text Available SciELO Venezuela | Language: Spanish Abstract in spanish Los metales pesados juegan un papel importante en la dinámica de los procesos químicos y ambientales en las zonas costeras. Estos provienen de aportes naturales y antropogénicos y pueden ser bioacumulados en organismos acuáticos, en los que se encuentran como elementos traza, y tienen potenciales ef [...] ectos tóxicos a quienes los consuman, principalmente al hombre como último eslabón de la cadena alimenticia. La gravedad del daño depende del grado y el tiempo de exposición a dichos elementos. Se determinó la concentración de metales pesados (Mg, Cu, Mn, Mo, Ni y Fe) por Plasma Inductivamente Acoplado (ICP) en la pepitona, Arca zebra (Mollusca, Bivalvia, Arcidae), provenientes de las inmediaciones de Caimancito y Chacopata (municipio Cruz Salmerón Acosta, estado Sucre, Venezuela). En Caimancito, las mayores concentraciones de casi todos los metales se detectaron en septiembre, a excepción del Mg que fue observada en febrero. En Chacopata, las concentraciones más elevadas se observaron en el mes de octubre (Mg, Mn y Ni), septiembre (Cu), diciembre (Fe) y en enero (Mo). No se encontraron diferencias significativas entre las localidades, mientras que existen diferencias significativas entre meses. Al momento no existen normas o regulaciones venezolanas que establezcan límites máximos de concentración de los metales analizados en moluscos bivalvos procesados o frescos, que permitan establecer comparaciones con los resultados obtenidos. Sin embargo, en base a normas internacionales, las concentraciones medidas de metales pesados en pepitonas no rebasaron los límites permitidos para consumo humano. Abstract in english Heavy metals play an important role in the dynamics of chemical and environmental processes in the coastal zones. They originate from natural and anthropogenic sources and can be bioaccumulated in aquatic organisms, where they are found as trace elements, and have potential toxic effects to those wh [...] o consume them, mainly to humans as the last link in the food chain. The severity of damage depends on the degree and time of exposure to these elements. The concentration of heavy metals (Mg, Cu, Mn, Mo, Ni and Fe) was estimated by Inductivelly Coupled Plasma (ICP) in the Turkey wing, Arca zebra (Mollusca, Bivalvia, Arcidae), from the vicinity to Caimancito and Chacopata (Municipality Cruz Salmerón Acosta, Sucre state, Venezuela). In Caimancito, higher concentrations of almost all metals were detected in September, except for Mg which was registered in February. In Chacopata, the highest concentrations were observed in October (Mg, Mn and Ni), September (Cu), December (Fe) and January (Mo). No significant differences were found between localities, while there were significant differences among months. At present there are not Venezuelan norms or regulations establishing the maximum concentration limits for the analyzed heavy metals in fresh or processed bivalve mollusks, which may enable comparisons with the obtained results. However, based upon international norms, the measured concentrations of heavy metals in Turkey wing apparently do not represent a threat for human consumption.

Vilma, Lanza; Ildemaro, Martínez; Osmicar, Vallenilla; Julia, Márquez; Arquímedes, González; Jesús, Gamboa; José, Alió.

2011-09-01

384

The zebras come to CERN  

CERN Multimedia

From 23 to 26 November CERN played host to an unusual group of visitors, who arrived in a red-and-white striped camper. On the tenth anniversary of "Les Zèbres”, a children’s broadcast on Swiss radio, the show’s makers invited 8th and 9th grade pupils from Swiss schools to conduct a live broadcast from CERN.   Students in the cryogenic hall: cryolab. Popular Franco-Swiss host Jean-Marc Richard brought Les Zèbres to the Laboratory with a live broadcast. The idea was to let the children themselves host the broadcast. Accompanied by their physics teachers, pupils from junior secondary schools in Golette, Colombières and Drize were given the opportunity to spend half a day at CERN. Each day, one class came to find out about a particular aspect of the Laboratory and then conduct a live broadcast with Jean-Marc Richard from 12:10 to 12:30. The young people, aged 13 to 15, had a chance to explore the Universe of Particles exhibitio...

Laëtitia Pedroso

2010-01-01

385

Mating preferences of zebra finches  

OpenAIRE

Kurzfassung zu: "Causes of between-individual differences in mating preferences". Dissertation an der Ludwig-Maximilians-Universität München, Fakultät für Biologie, durchgeführt am Max-Planck-Institut für Ornithologie in Seewiesen, betreut von Dr. Wolfgang Forstmeier und Prof. Bart Kempenaers (2009).

Schielzeth, Holger

2012-01-01

386

77 FR 26779 - Endangered Species; Receipt of Applications for Permit  

Science.gov (United States)

...Grevy's zebra (Equus grevyi) Eld's deer (Rucervus eldii) barasingha (Rucervus duvaucelii) Formosan sika deer (Cervus nippon taiouanus) bontebok (Damaliscus pygargus pygargus) addax (Addax nasomaculatus) red lechwe (Kobus leche)...

2012-05-07

387

Induction of heat shock proteins (hsp70) in the zebra mussel (Dreissena polymorpha) following exposure to platinum group metals (platinum, palladium and rhodium): Comparison with lead and cadmium exposures  

International Nuclear Information System (INIS)

An increasing number of papers concentrate on the availability and uptake of platinum group elements (PGE) by different organisms. These metals are discharged into the environment from different anthropogenic sources, such as automobile catalytic converters, hospitals and other medical institutions. As the effects of these precious metals on organisms remain unclear, the induction of heat shock proteins (hsp70) in zebra mussels (Dreissena polymorpha) following exposure to soluble salts of platinum, palladium and rhodium was compared with the hsp70 induction in mussels following exposure to cadmium and lead. Mussels were sampled weekly during a period of 10 weeks and analyzed for their metal concentration and their hsp70 level. Highest metal uptake was found for Cd, followed by Pt, Pb and Pd. Rh demonstrated the lowest uptake rate. A clear time-dependent increase of hsp70 levels occurred in all exposed mussels. Concentrations of hsp70 started to rise between days 18 and 25, except for the Pt-exposed group, where the initial increase was between days 25 and 32. All groups reached maximal hsp70 concentrations at day 39. Subsequently, hsp70 levels decreased to initial levels for the remaining exposure period. Threshold metal levels for the hsp70 induction varied among the metals and increased in the order: Rh < Pd ? Pb < Pt < Cd. Highest hsp70 values were found for mussels exposed to Pd, with a 25-fold higher level than in the controls, followed by Pt- and Rh-exposed mutrols, followed by Pt- and Rh-exposed mussels, which showed a 19-fold increase. The hsp70 levels of the mussels exposed to Cd and Pb were much lower, showing 6- and 12-fold higher values than the control, respectively. The clear induction of hsp70 due to exposure to Pt, Pd and Rh gives evidence for strong cellular effects of these metals, especially, when compared with lead and cadmium. Among the metals tested, Pd seems to have the highest potential as inducer for hsp70 production due to its low threshold level in combination with the strongest effect

388

Induction of heat shock proteins (hsp70) in the zebra mussel (Dreissena polymorpha) following exposure to platinum group metals (platinum, palladium and rhodium): Comparison with lead and cadmium exposures  

Energy Technology Data Exchange (ETDEWEB)

An increasing number of papers concentrate on the availability and uptake of platinum group elements (PGE) by different organisms. These metals are discharged into the environment from different anthropogenic sources, such as automobile catalytic converters, hospitals and other medical institutions. As the effects of these precious metals on organisms remain unclear, the induction of heat shock proteins (hsp70) in zebra mussels (Dreissena polymorpha) following exposure to soluble salts of platinum, palladium and rhodium was compared with the hsp70 induction in mussels following exposure to cadmium and lead. Mussels were sampled weekly during a period of 10 weeks and analyzed for their metal concentration and their hsp70 level. Highest metal uptake was found for Cd, followed by Pt, Pb and Pd. Rh demonstrated the lowest uptake rate. A clear time-dependent increase of hsp70 levels occurred in all exposed mussels. Concentrations of hsp70 started to rise between days 18 and 25, except for the Pt-exposed group, where the initial increase was between days 25 and 32. All groups reached maximal hsp70 concentrations at day 39. Subsequently, hsp70 levels decreased to initial levels for the remaining exposure period. Threshold metal levels for the hsp70 induction varied among the metals and increased in the order: Rh < Pd {<=} Pb < Pt < Cd. Highest hsp70 values were found for mussels exposed to Pd, with a 25-fold higher level than in the controls, followed by Pt- and Rh-exposed mussels, which showed a 19-fold increase. The hsp70 levels of the mussels exposed to Cd and Pb were much lower, showing 6- and 12-fold higher values than the control, respectively. The clear induction of hsp70 due to exposure to Pt, Pd and Rh gives evidence for strong cellular effects of these metals, especially, when compared with lead and cadmium. Among the metals tested, Pd seems to have the highest potential as inducer for hsp70 production due to its low threshold level in combination with the strongest effect.

Singer, Christoph [Zoologisches Institut I-Oekologie, Universitaet Karlsruhe, Geb. 07.01, Kornblumenstrasse 13, D-76131 Karlsruhe (Germany); Zimmermann, Sonja [Zoologisches Institut I-Oekologie, Universitaet Karlsruhe, Geb. 07.01, Kornblumenstrasse 13, D-76131 Karlsruhe (Germany); Sures, Bernd [Zoologisches Institut I-Oekologie, Universitaet Karlsruhe, Geb. 07.01, Kornblumenstrasse 13, D-76131 Karlsruhe (Germany)]. E-mail: dc11@rz.uni-karlsruhe.de

2005-10-05

389

Metabolic ageing in individual zebra finches  

OpenAIRE

Oxidative stress is suggested as a contributor to the ageing process. Knowledge of the relationship between age and energy expenditure may contribute to our understanding of ageing patterns, due to the link between oxygen consumption and free radical production. However, studies on basal metabolic rate (BMR) and age have generally been cross-sectional, which may confound estimates of the age effect due to disproportionate mortality (also known as ‘selective disappearance’). We therefore p...

Moe, Børge; Rønning, Bernt; Verhulst, Simon; Bech, Claus

2009-01-01

390

What, If Anything, is a Zebra?  

Science.gov (United States)

This lesson is based on an essay by Stephen Jay Gould and on the related reading guide. It addresses the issue of cladistics and some of the problems encountered in the science of Systematics. Students will learn that biological classification is intimately associated with evolution. They will also learn that there are many problems encountered in classification, providing evidence that the living world is a work in progress. Evolution provides an explanation for those problems.

Nelson, Craig

391

Macrorhabdus ornithogaster in ostrich, rhea, canary, zebra finch, free range chicken, turkey, guinea-fowl, columbina pigeon, toucan, chuckar partridge and experimental infection in chicken, japanese quail and mice / Macrorhabdus ornithogaster em avestruzes, ema, canário, mandarim, galinha, peru, galinha da Angola, pombo doméstico, rolinha, tucano, perdiz de chuckar e infecção experimental em galinha, codorna e camundongo  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in portuguese Desde 2000, diversos casos de infecção e doença por Macrorhabdus ornithogaster (megabacteria) foram diagnosticados no Setor de Doenças das Aves (Escola de Veterinária da UFMG). A doença clínica foi caracterizada por emagrecimento, prostração, perda do apetite, caquexia e morte, em curso crônico, emb [...] ora com forma mais aguda em canários e periquitos. O microrganismo grande, em forma de bastão, visível a partir de 100 aumentos sem e com coloração, pode também ser detectado em aves de aspecto clínico normal, principalmente galinhas, perus, codornas e pombos. Em emas (Rhea), avestruzes (Struthio camelus), canários, mandarins, galinhas da Angola (Numida meleagris) e periquitos Australianos (Melopsittacus undulatus), a severidade da doença foi sempre maior, ocasionando até 100% de mortalidade em alguns plantéis. Na maioria das espécies a doença foi detectada em aves com endo e/ou ectoparasitismo. O cultivo de M. ornithogaster foi obtido em meio sólido (ágar para fungos patogênicos) e subcultivado em meio líquido (thioglicolato), do proventriculo de galinha, galinha da Angola, perdiz de chuckar e canário. O resultado mais surpreendente na microscopia de M. ornithogaster foi a presença de motilidade, detectada tanto de cultivos in vitro quanto de preparações úmidas de in vivo. Diferenças nos aspectos das colônias foram notadas entre os isolados. Infecções experimentais em galinha (SPF) e codorna japonesa permitiram a detecção do organismo nos proventrículos das aves de aspecto normal. Nas codornas, à necropsia notaram-se hemorragias hepáticas. A infecção experimental em camundongos via intraperitoneal resultou em 100% de mortalidade, também com lesões hepáticas. Aspectos do cultivo, a importância da doença, as espécies de aves susceptíveis e seu papel na epidemiologia são discutidos. Abstract in english Since 2000, Macrorhabdus ornithogaster "megabacteriosis" has been diagnosed in the avian diseases laboratory in a diversity of avian species and varied spectrum of disease. The disease in some species (chickens, turkeys, guinea fowls) was clinically characterized by emaciation, prostration, loss of [...] appetite, cachexia and death, with a typically chronic course. A more acute disease was observed in finches (canary-Serinus and zebra-Taeniopygia) and budgerigars (Melopsittacus undulatus). The large rod shaped organism, visible from 100 times magnification, with and without staining, could be detected in sick and also in reasonably normal individuals of some species, such as chickens, turkeys, quails and pigeons. In rheas (Rhea americana), ostriches (Struthio camelus), canaries, zebra-finches, guinea-fowl (Numida meleagris) and budgerigars. The disease was severe, causing to up to 100% mortality. The infection could be detected in some species along with other infectious or disease problems, such as endoparasites (helminths, coccidia) and ectoparasitism (order Mallophaga or/and order Acarina). The cultivation of M. ornithogaster was successfully achieved in solid and liquid media, originated from chickens (four isolates), guinea fowl (1 isolate), chuckar partridge (1 isolate) and canary (1 isolate). A very interesting finding at microscopy was motility of M. ornithogaster, as detected both in cultures obtained on agar for pathogenic fungi and passaged into thioglycolate broth, as well as on samples observed in wet preparations from in vivo. Differences in colony aspects were noted among the isolates. Experimental infections were attempted in chicken and japanese quail, using a chicken isolate, allowing the detection of the organism in the proventriculus and liver in apparently normal birds. One chicken isolate was injected intraperitoneally in Balb/c mice and resulted in 100% mortality.

N.R.S., Martins; A.C., Horta; A.M., Siqueira; S.Q., Lopes; J.S., Resende; M.A., Jorge; R.A., Assis; N.E., Martins; A.A., Fernandes; P.R., Barrios; T.J.R., Costa; L.M.C., Guimarães.

2006-06-01

392

Macrorhabdus ornithogaster in ostrich, rhea, canary, zebra finch, free range chicken, turkey, guinea-fowl, columbina pigeon, toucan, chuckar partridge and experimental infection in chicken, japanese quail and mice Macrorhabdus ornithogaster em avestruzes, ema, canário, mandarim, galinha, peru, galinha da Angola, pombo doméstico, rolinha, tucano, perdiz de chuckar e infecção experimental em galinha, codorna e camundongo  

Directory of Open Access Journals (Sweden)

Full Text Available Since 2000, Macrorhabdus ornithogaster "megabacteriosis" has been diagnosed in the avian diseases laboratory in a diversity of avian species and varied spectrum of disease. The disease in some species (chickens, turkeys, guinea fowls was clinically characterized by emaciation, prostration, loss of appetite, cachexia and death, with a typically chronic course. A more acute disease was observed in finches (canary-Serinus and zebra-Taeniopygia and budgerigars (Melopsittacus undulatus. The large rod shaped organism, visible from 100 times magnification, with and without staining, could be detected in sick and also in reasonably normal individuals of some species, such as chickens, turkeys, quails and pigeons. In rheas (Rhea americana, ostriches (Struthio camelus, canaries, zebra-finches, guinea-fowl (Numida meleagris and budgerigars. The disease was severe, causing to up to 100% mortality. The infection could be detected in some species along with other infectious or disease problems, such as endoparasites (helminths, coccidia and ectoparasitism (order Mallophaga or/and order Acarina. The cultivation of M. ornithogaster was successfully achieved in solid and liquid media, originated from chickens (four isolates, guinea fowl (1 isolate, chuckar partridge (1 isolate and canary (1 isolate. A very interesting finding at microscopy was motility of M. ornithogaster, as detected both in cultures obtained on agar for pathogenic fungi and passaged into thioglycolate broth, as well as on samples observed in wet preparations from in vivo. Differences in colony aspects were noted among the isolates. Experimental infections were attempted in chicken and japanese quail, using a chicken isolate, allowing the detection of the organism in the proventriculus and liver in apparently normal birds. One chicken isolate was injected intraperitoneally in Balb/c mice and resulted in 100% mortality.Desde 2000, diversos casos de infecção e doença por Macrorhabdus ornithogaster (megabacteria foram diagnosticados no Setor de Doenças das Aves (Escola de Veterinária da UFMG. A doença clínica foi caracterizada por emagrecimento, prostração, perda do apetite, caquexia e morte, em curso crônico, embora com forma mais aguda em canários e periquitos. O microrganismo grande, em forma de bastão, visível a partir de 100 aumentos sem e com coloração, pode também ser detectado em aves de aspecto clínico normal, principalmente galinhas, perus, codornas e pombos. Em emas (Rhea, avestruzes (Struthio camelus, canários, mandarins, galinhas da Angola (Numida meleagris e periquitos Australianos (Melopsittacus undulatus, a severidade da doença foi sempre maior, ocasionando até 100% de mortalidade em alguns plantéis. Na maioria das espécies a doença foi detectada em aves com endo e/ou ectoparasitismo. O cultivo de M. ornithogaster foi obtido em meio sólido (ágar para fungos patogênicos e subcultivado em meio líquido (thioglicolato, do proventriculo de galinha, galinha da Angola, perdiz de chuckar e canário. O resultado mais surpreendente na microscopia de M. ornithogaster foi a presença de motilidade, detectada tanto de cultivos in vitro quanto de preparações úmidas de in vivo. Diferenças nos aspectos das colônias foram notadas entre os isolados. Infecções experimentais em galinha (SPF e codorna japonesa permitiram a detecção do organismo nos proventrículos das aves de aspecto normal. Nas codornas, à necropsia notaram-se hemorragias hepáticas. A infecção experimental em camundongos via intraperitoneal resultou em 100% de mortalidade, também com lesões hepáticas. Aspectos do cultivo, a importância da doença, as espécies de aves susceptíveis e seu papel na epidemiologia são discutidos.

N.R.S. Martins

2006-06-01

393

Study of the biological effects of uranium exposure on zebra fish (D. rerio). Impact on life stages; Etude des effets biologiques de l'exposition a l'uranium chez le poisson zebre (D. rerio). Impact sur les stades de vie  

Energy Technology Data Exchange (ETDEWEB)

This work is part of an ongoing project (ENVIRHOM) started at IRSN in 2000, which consists in studying the environmental effects of radioactive substances at chronic low level of exposure. In this general frame, our aim was two fold: (i) to identify sensitivity of different critical life stages of zebra fish (fish of fresh water frequently used for tests standards in ecotoxicology) to uranium exposure and (ii) to evaluate underlying mechanisms. Experiments were conducted with eggs, larvae and genitors exposed to uranium at environmentally relevant concentrations (from 20 to 500 {mu}g/L) in order to study survival, hatching of eggs, growth of larvae and reproduction of genitors. Bio-markers of exposure (i.e. U bioaccumulation) and bio-markers of effects at molecular level (i.e. genotoxic effects, reproductive-toxicity) were also measured. Sensitivity of fish to uranium was dependent of the life stage of development with the early life stage being the most sensitive to U either directly or maternally exposed. It underlines the relevance of including pro-larval stages for toxicity assessments in fish. Moreover drastic effects of uranium on reproductive success and DNA damages in the germ cells foretell a strong impact on the population for low concentration of exposure (20 {mu}g/L). As it is increasingly recognized that population-level effects of toxic substances are more relevant in terms of ecological risk assessment, this study points out the need to include different life stages of organisms in eco-toxicological studies, especially the sensitive early stages. Moreover, it appears, through the comparative study of the radiological effects or by another isotope of the uranium of stronger radioactivity ({sup 233}U or by an irradiation with {sup 137}Cs), that the effects of the uranium are due to its chemo-toxicity. (author)

Bourrachot, St.

2009-05-15

394

The Leopard Tortoise in the Mountain Zebra National Park  

Directory of Open Access Journals (Sweden)

Full Text Available A total of 69 leopard tortoises Geochelone pardalis babcocki (Loveridge 1935 were captured, marked, sexed, weighed and released. The results of this exercise together with other field data are presented and discussed.

J. H Grobler

1982-11-01

395

Food quality controls reproduction of the zebra mussel (Dreissena polymorpha).  

Science.gov (United States)

Species such as Dreissena polymorpha sometimes contribute substantially in the transfer of primary to secondary production. During the ontogenetic cycle, the reproductive investment of adult mussels is one of the main parameters that affect recruitment success. We studied how food quality and temperature affect the reproductive investment in term of egg mass of D. polymorpha in a lake by sampling mussels monthly from 4 m and 15 m depths. Temperature affected reproduction directly and also indirectly through the food. To assess whether temperature and/or food conditions led to the differences observed in mussels sampled from the two depths, mussels were reared in the laboratory under two different temperature regimes for 3 months, simulating the temperature of the lake at 4 m and 15 m depth. Possible effects of food quality were tested at each temperature using four diets differing in fatty acid composition. Temperature played an important role as a trigger for spawning, and the type of diet clearly affected the reproductive investment. When the heterokont chromophyte alga Nannochloropsis limnetica, which is rich in polyunsaturated fatty acids (PUFAs) and long-chained PUFAs (>C18), was fed to mussels, an increased egg mass was obtained. This result was in contrast to that found when the green alga Scenedesmus obliquus and the cyanobacterium Aphanothece sp., both of which are deficient in long-chained PUFAs, were offered as food to the mussels. Such a PUFA-dependent food quality may affect reproduction in lakes. Food quality effects vary seasonally in a lake and may be most important in summer, when low-food-quality green algae and cyanobacteria are abundant. The low biochemical quality of these blooms may affect at least the later period of gametogenesis of D. polymorpha, which reproduces from June to August. PMID:12721821

Wacker, Alexander; Von Elert, Eric

2003-05-01

396

On the ontogeny of species recognition in zebra finches  

OpenAIRE

In hoofdstuk 2 worden de argumenten gegeven waaruit zou blijken dat zebravinkmannetjes een niet-geleerde voorkeur voor kenmerken van hun eigen soort hebben. Deze argumentatie gaat uit van de vooronderstelling dat ouders van de eigen soort en japanse meeuwen een gelijkwaardige rol spelen in het inprentingsproces. ... Zie: Samenvatting

Cate, Carel Jacob Ten

1984-01-01

397

Presumed Mycobacteriosis in Laboratory Zebra Finch (Taeniopygia guttata)  

OpenAIRE

Husbandry staff noticed a research-naïve, young-adult, female finch tossing its head back intermittently. A second finch exhibiting similar signs was reported a few days later. Postmortem necropsy and histopathology with hematoxylin and eosin and acid-fast staining on the first finch revealed the presence of acid-fast organisms in several organs. After presumptive diagnosis of mycobacteriosis, all remaining finches housed in the same room as the first underwent necropsy and histology. Three ...

Asfaw, Yohannes G.; Sun, Francis J.

2010-01-01

398

Zebra mussel effects on benthic invertebrates: physical or biotic?  

Science.gov (United States)

In soft sediments, Dreissena spp. create firm substrate in the form of aggregates of living mussels (druses) that roll free on the sediments. Druses provide physical structure which increases habitat heterogeneity, and the mussels increase benthic organic matter through the production of pseudofeces and feces. Descriptive and experimental studies were used to determine: 1) whether the density of benthic invertebrates in soft sediments increased in the presence of druses, and 2) whether the invertebrate assemblage responded to the physical structure provided by a druse or to some biotic effect associated with the presence of living mussels. In core samples collected biweekly during summer in Presque Isle Bay, Erie, Pennsylvania, amphipods, chironomids, oligochaetes, turbellarians, and hydrozoans were significantly more abundant in sand with druses than in bare sand. When mesh bags containing either a living druse, non-living druse, or no druse were incubated in the bay for 33 d, we found that chironomids were significantly more abundant in treatments with living druses than with non-living druses, and in treatments with non-living druses than with no druse; turbellarians, amphipods, and hydrozoans were significantly more abundant in treatments with living or non-living druses than with no druse; oligochaetes showed no significant differences among treatments. This study demonstrates that most taxa of benthic invertebrates in soft substrate respond specifically to the physical structure associated with aggregates of mussel shells, but further study is needed to examine chironomid responses to some biotic effect dependent on the presence of living mussels.

Botts, P. Silver; Patterson, Benjamin A.; Schloesser, Don W.

1996-01-01

399

Further bird records from the Bontebokand Mountain Zebra National Parks  

Directory of Open Access Journals (Sweden)

Full Text Available

The avifauna of this Park is well-known. Shortly after the Park was relocated to Swellendam in 1960, a preliminary list of the birds of the Park was published (Winterbottom 1962a. This was soon followed by a comprehensive check list (Winterbottom 1967a and a report on bird densities in the Coastal Renosterbosveld of the Park (Winterbottom 1968a. Six further bird species, five of which have been reported in The Ostrich, are documented here, increasing to 150 the total number of species recorded in the Park. The numbers denote those used in Roberts birds of South Africa (McLachlan and Liversidge 1970 and the nomenclature follows the Check list of the birds of South Africa (S.A.O.S. List Committee 1969.

B.L. Penzhorn

1977-08-01

400

Infecção natural de Equus caballus por Leishmania sp - São Paulo, Brasil (Breve comunicação científica) Natural infection of Equus caballus by Leishmania sp in São Paulo, Brazil, (Short communication)  

OpenAIRE

E assinalado, pela primeira vez, o encontro de um cavalo (Equus caballus) infeclado por Leishmania sp, no Estado de São Paulo.In São Paulo State a horse (Equus caballus) was found infected with Leishmania sp, for the first time.

Elizaide Luzia de Alvarenga Yoshida; Sílvio de Alencar Marques; Hamilton Ometto Stolf; Luiz Antonio Barsotti; Márcia Maria Fattori Bueno; Roberto Sogayar

1988-01-01

401

Características morfológicas do funículo espermático do burro (Equus asinus x Equus caballus) / Morphological aspects of the spermatic cord in mules (Equus asinus x Equus caballus)  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Estudando 15 pares de funículos espermáticos de burros (Equus asinus x Equus caballus), observamos em 5 pares que seus componentes acham-se envolvidos por delgada cápsula de tecido conjuntivo denso, revestido por mesotélio. Sob esta cápsula e em estreita relação com ela encontra-se espessa camada de [...] musculatura lisa (músculo cremáster interno) que acompanha também o mesoducto deferente. A cápsula funicular e o músculo cremáster interno aparecem em alguns pontos levemente pregueados. Os componentes vásculo-nervosos estão envolvidos por tecido conjuntivo frouxo integrado predominantemente por fibras colágenas. A artéria testicular no funículo mostra trajeto sinuoso, túnica interna constituída por endotélio acompanhado de delicada camada de tecido conjuntivo e lâmina elástica limitante interna. Sua espessa túnica média é composta por fibras musculares lisas sustentadas por rede de fibras reticulares, e a túnica externa, por tecido conjuntivo que se confunde com o tecido conjuntivo intervascular. As veias testiculares aparecem em grande número, possuem túnica média formada por fibras elásticas e reticulares, com poucas fibras musculares e são desprovidas de válvulas, envolvem as artérias testiculares formando os plexos pampiniformes. O modelo do segmento da artéria testicular obtido com Neoprene látex 450 em 20 preparações, correspondentes a 10 pares de funículos espermáticos, apresentaram, respectivamente como comprimentos médio, máximo e mínimo, 58,2 cm, 81,0 cm e 44,0 cm à direita e 66,3 cm, 96,0 cm e 51,0 cm à esquerda. Abstract in english In a morphologic study of 15 spermatic cord pairs of male mules (Equus asinus x Equus caballus), histology showed in 5 pairs that its components are involved in a thin capsule of a dense connective tissue, covered by a mesothelium. Underneath the capsule, in a close relation, we identified the inter [...] nal cremaster muscle. This muscle goes with mesoductus. The funicular capsule and muscular tissue form a few small plicae. The funicular vessels (testicular artery and veins) are wrapped up in loose conjunctive tissue prevailing collagen fibers. The funicular part of the testicular artery is convoluted. It shows a thick tunica média vasorum supported by a net of reticular fibers; tunica intima vasorum is build up endothelium, thin connective tissue and a well defined internal elastic layer; tunica externa vasorum with the connective tissue becoming part of intervascular connective tissue. The testicular veins constituted a very elaborated close-meshed pampiniform plexus in which contortions of the artery are embedded. These veins have a medial tunic formed by elastic and reticular fibers, with a few muscular fibers without valves. The part of testicular artery model obtained with Neoprene latex 450 in 20 preparations, corresponding to 10 pairs of spermatic cords, have mean, maximum, and minimum lengths, respectively, of 58,2 cm, 81 cm, and 44 cm to the right side and 66,5 cm, 96 cm, and 51 cm to the left side.

Roberto Pimenta de Pádua, FOZ FILHO; Antônio, FERNANDES FILHO; Vicente, BORELLI.

402

Infecção natural de Equus caballus por Leishmania sp - São Paulo, Brasil (Breve comunicação científica Natural infection of Equus caballus by Leishmania sp in São Paulo, Brazil, (Short communication  

Directory of Open Access Journals (Sweden)

Full Text Available E assinalado, pela primeira vez, o encontro de um cavalo (Equus caballus infeclado por Leishmania sp, no Estado de São Paulo.In São Paulo State a horse (Equus caballus was found infected with Leishmania sp, for the first time.

Elizaide Luzia de Alvarenga Yoshida

1988-04-01

403

Research on Donkey Populations (Equus Asinus) in Banat  

OpenAIRE

Research has been made in what concerns the bodily development of donkeys (Equus asinus) in Banat, on a number of 94 specimens. The results have shown a great variety in body measures, colours and hues. The Banat Donkey comes from different areas in Romania, Europe or Levant. In 2010 in Banat there were approx. 1000 donkey specimens, 98% of which pertained to shepherds. In the case of this species the mating occurs naturally, and a selection has never been made. Their meat and m...

Marcel Matiuti; Carmen-Luminita Matiuti; Dorel Dronca; Eleonora Nistor; Teodor Mot

2011-01-01

404

Esteatosis en un burro (Equus asinus). Primer reporte en Colombia / Steatosis in donkey (Equus asinus). First report in Colombia  

Scientific Electronic Library Online (English)

Full Text Available SciELO Colombia | Language: Spanish Abstract in spanish Se describe un caso de esteatosis en un burro (Equus asinus), castrado, de 15 años de edad, procedente del municipio de San Antero (Córdoba, Colombia), al cual se le detectó ligamento nucal engrosado, duro y doloroso, dando la impresión de un doble cuello y edemas subcutáneos indurados en pared cost [...] al, abdominal y pectoral. También presentó masas duras en la unión de músculos semimembranoso y semitendinoso. Por todo lo anterior, mostró dificultad para realizar movimientos coordinados del cuello, nuca y de traslado. Estos hallazgos obedecen principalmente a una deficiencia de selenio y vitamina E, sirviendo como parámetro diagnóstico para la identificación de esta enfermedad en equinos, por lo cual se determinó la actividad eritrocitica de la enzima glutatión peroxidada (GSH-Px), arrojando resultados muy bajos. Este cuadro es también conocido en equinos como enfermedad de la grasa amarilla o esteatitis, que produce degeneración del tejido adiposo, siendo reemplazado por tejido conectivo con depósitos de calcio. Puede estar asociada a miodegeneración nutricional o distrófica (enfermedad del músculo blanco). Es el primer reporte de esta enfermedad en burros (Equus asinus) que se hace en Colombia. Abstract in english A case of steatosis in a, 15 years old gelding donkey (Equus asinus), from the town of San Antero (Cordoba, Colombia) is described. the donkey, showed a hard and painful thickened nuchal ligament, giving the impression of a double neck tumors. It was also found an edema in the indurated subcutaneous [...] chest wall, abdomen and chest. It was also found hard lumps in the union of semimembranosus and semitendinosus muscles, which produced difficulty in the movility of the neck and coordinated translation. It is well known that this findings are due to a deficiency of selenium and vitamin E, giving them as diagnostic parameters for the presentation of this disease in horses, so we determined the enzyme activity of erythrocyte glutathione peroxidase (GSH-Px), yielding results very low. This condition is also known as yellow fat disease or steatitis in horses and produces degeneration of adipose tissue which is replaced by connective tissue and calcium deposits and may be associated with nutritional or dystrophic miodegeneration (white muscle disease). As far as we know this is the first report of steatosis in donkeys (Equus asinus) in Colombia.

José, Cardona; Lázaro, Reza G.

2793-27-01

405

Esteatosis en un burro (Equus asinus. Primer reporte en Colombia  

Directory of Open Access Journals (Sweden)

Full Text Available Se describe un caso de esteatosis en un burro (Equus asinus, castrado, de 15 años de edad, procedente del municipio de San Antero (Córdoba, Colombia, al cual se le detectó ligamento nucal engrosado, duro y doloroso, dando la impresión de un doble cuello y edemas subcutáneos indurados en pared costal, abdominal y pectoral. Tambiénpresentó masas duras en la unión de músculos semimembranoso y semitendinoso. Por todo lo anterior, mostró dificultad para realizar movimientos coordinados del cuello, nuca y de traslado. Estos hallazgos obedecen principalmente a una deficiencia de selenio y vitamina E, sirviendo como parámetro diagnóstico para la identificación de esta enfermedad en equinos, por lo cual se determinó la actividad eritrocitica de la enzima glutatión peroxidada (GSH-Px, arrojando resultados muy bajos. Este cuadro es también conocido en equinos como enfermedad de la grasa amarilla o esteatitis, que produce degeneración del tejido adiposo, siendo reemplazado por tejido conectivo con depósitos de calcio. Puede estar asociada a miodegeneración nutricional o distrófica (enfermedad del músculo blanco. Es el primer reporte de esta enfermedad en burros(Equus asinus que se hace en Colombia.

José Cardona Á.

2011-12-01

406

Nuevo registro de Equus (Amerhippus) santaeelenae (Mammalia, Perissodactyla) del pozo de asfalto de Inciarte (Pleistoceno Superior), estado Zulia, Venezuela / New record of Equus (Amerhippus) santaeelenae (Mammalia, Perissodactyla) from the Pozo de asfalto de Inciarte site (Late Pleistocene), Zulia State, Venezuela  

Scientific Electronic Library Online (English)

Full Text Available SciELO Argentina | Language: Spanish Abstract in spanish Los fósiles de Equidae del pozo de asfalto de Inciarte son descritos y determinados taxonómicamente. Se han comparado los p3-4 inferiores de Inciarte con los de Equus (Amerhippus) andium, Equus (A.) santaeelenae, Equus (A.) insulatus y Equus (A.) neogeus de varias localidades de América del Sur medi [...] ante análisis multivariante. Los resultados de este análisis indican que la especie Equus (Amerhippus) santaeelenae (Spillmann) está representada en el yacimiento. Se discuten sus implicaciones paleoecológicas. Algunos autores sugieren que un estrés nutricional, producto de un cambio rápido en las comunidades vegetales, podría ser una de las causas que expliquen la extinción de fines del Pleistoceno. La especialización en la dieta que se atribuye a esta especie es una evidencia en favor de esta teoría. Abstract in english Fossil remains of Equidae from the asphaltic well of Inciarte quarry are described and taxonomically determined. We compared the lower p3-4 from Inciarte with Equus (Amerhippus) andium, Equus (A.) santaeelenae, E. (A.) insulatus and Equus (A.) neogeus remains from several localities in South America [...] using multivariate analysis. The results of this analysis indicate that Equus (Amerhippus) santaeelenae (Spillmann) is represented in the quarry. Its paleoecological implications are discussed. The resource partitioning preference of this species supports the several nutritional hypotheses to explain latest Pleistocene extinctions.

Ascanio D., Rincón R.; María Teresa, Alberdi; José Luis, Prado.

2006-09-01

407

A note on the smaller mammals of the Mountain Zebra National Park  

Directory of Open Access Journals (Sweden)

Full Text Available Collecting in April 1971 yielded 74 specimens of 16 species. Of these, seven species (Elephantulus rupestris, Lepus saxatilis, Pronolagus crassicaudatus, Graphiurus murinus, Aethomys namaquensis, Desmodillus auricularis and Gerbillurus paeba are new records for the park. Distribution in habitat-types for each species known to occur are described.

J. J. L. Pretorius

1971-05-01

408

Genotoxicity and activation of cellular defenses in transplanted zebra mussels Dreissena polymorpha along the Seine river.  

Science.gov (United States)

The aim of the present study was to confirm the relevance of studying DNA adduct formation in a field study. In that context, freshwater mussels Dreissena polymorpha, collected in a reference station, were transplanted in different sites with a pollution gradient. After one and two months, mussels were collected and DNA adduct formation was analyzed using the (32)P post labelling technique on both gills and digestive glands. In addition, the expression of genes involved in the detoxification system (catalase (CAT), superoxide dismutase (SOD), glutathione S-transferase (GST), HSP70, aryl hydrocarbon receptor (AHR), P glycoprotein (PgP), metallothionein (MT)) was assessed by RT-PCR. DNA adducts were observed at amount comparable to data from literature. Increase of DNA adducts after two months of transplantation could be correlated with strong modulation of gene expression implicated in detoxification processes. Indeed, PgP and HSP70 gene expressions were similarly induced in gills and digestive glands while SOD and CAT expressions were down regulated in both tissues. AHR, GST and MT genes were differently regulated depending upon the tissue studied and the level of contamination in the different sites. We demonstrated that mussels transplanted in the different stations with pollution gradient were able to biotransform PAHs, assessed by DNA adduct formation and the high decrease of detoxification genes. Specific DNA adducts pattern obtained after one and two month mussel transplantations demonstrated the relevance of DNA adduct as biomarker of environmental pollution. PMID:24951272

Châtel, Amélie; Faucet-Marquis, Virginie; Gourlay-Francé, Catherine; Pfohl-Leszkowicz, Annie; Vincent-Hubert, Françoise

2014-06-17

409

Immediate and delayed effects of growth conditions on ageing parameters in nestling zebra finches.  

Science.gov (United States)

Conditions experienced during development and growth are of crucial importance as they can have a significant influence on the optimisation of life histories. Indeed, the ability of an organism to grow fast and achieve a large body size often confers short- and long-term fitness benefits. However, there is good evidence that organisms do not grow at their maximal rates as growth rates seem to have potential costs on subsequent lifespan. There are several potential proximate causes of such a reduced lifespan. Among them, one emerging hypothesis is that growth impacts adult survival and/or longevity through a shared, end point, ageing mechanism: telomere erosion. In this study, we manipulated brood size in order to investigate whether rapid growth (chicks in reduced broods) is effectively done at the cost of a short- (end of growth) and long-term (at adulthood) increase of oxidative damage and telomere loss. Contrary to what we expected, chicks from the enlarged broods displayed more oxidative damage and had shorter telomeres at the end of the growth period and at adulthood. Our study extends the understanding of the proximate mechanisms involved in the trade-off between growth and ageing. It highlights that adverse environmental conditions during growth can come at a cost via transient increased oxidative stress and pervasive eroded telomeres. Indeed, it suggests that telomeres are not only controlled by intrinsic growth rates per se but also may be under the control of some extrinsic environmental factors, which could complicate our understanding of the growth-ageing interaction. PMID:25524985

Reichert, Sophie; Criscuolo, François; Zahn, Sandrine; Arrivé, Mathilde; Bize, Pierre; Massemin, Sylvie

2015-02-01

410

Meiotic silencing and fragmentation of the male germline restricted chromosome in zebra finch  

OpenAIRE

During male meiotic prophase in mammals, X and Y are in a largely unsynapsed configuration, which is thought to trigger meiotic sex chromosome inactivation (MSCI). In avian species, females are ZW, and males ZZ. Although Z and W in chicken oocytes show complete, largely heterologous synapsis, they too undergo MSCI, albeit only transiently. The W chromosome is already inactive in early meiotic prophase, and inactive chromatin marks may spread on to the Z upon synapsis. Mammalian MSCI is consid...

Schoenmakers, Sam; Wassenaar, Evelyne; Laven, Joop S. E.; Grootegoed, J. Anton; Baarends, Willy M.

2010-01-01

411

Histological changes and Micronucleus induction in the Zebra mussel Dreissena polymorpha after Paraquat exposure  

OpenAIRE

The herbicide paraquat (PQ), still widely used in developing countries, represents a serious risk factor for human and environmental health. To test the sublethal effects of PQ on the freshwater bivalve Dreissena polymorpha, mussels were exposed to 0.125, 0.250, 0.500 mg/L for 7 and 14 days and histologically screened. PQ’s genotoxic potential was also determined in haemocytes by the micronucleus, MN, assay. At concentrations ³ 0.250mg/L, severe lesions, suc...

Mantecca, P.; Vailati, G.; Bacchetta, R.

2006-01-01

412

Variation in the volume of zebra finch song control nuclei is heritable: developmental and evolutionary implications.  

OpenAIRE

In many songbird species, females prefer males that sing a larger repertoire of syllables. Males with more elaborate songs have a larger high vocal centre (HVC) nucleus, the highest structure in the song production pathway. HVC size is thus a potential target of sexual selection. Here we provide evidence that the size of the HVC and other song production nuclei are heritable across individual males within a species. In contrast, we find that heritabilities of other nuclei in a song-learning p...

Airey, D. C.; Castillo-juarez, H.; Casella, G.; Pollak, E. J.; Devoogd, T. J.

2000-01-01

413

Song-selective auditory circuits in the vocal control system of the zebra finch.  

OpenAIRE

Birdsong is a learned behavior controlled by a distinct set of brain nuclei. The song nuclei known as area X, the medial nucleus of the dorsolateral thalamus (DLM), and the lateral magnocellular nucleus of the anterior neostriatum (L-MAN) form a pathway that plays an important but unknown role in song learning. One function served by this circuit might be auditory feedback, which is critical to normal song development. We used single unit recordings to demonstrate that all three of these nucl...

Doupe, A. J.; Konishi, M.

1991-01-01

414

Genesis of self-organized zebra textures in burial dolomites : displacive veins, induced stress, and dolomitization  

OpenAIRE

The dolomite veins making up rhythmites common in burial dolomites are not cement infillings of supposed cavities, as in the prevailing view, but are instead displacive veins, veins that pushed aside the host dolostone as they grew. Evidence that the veins are displacive includes a) small transform-fault-like displacements that could not have taken place if the veins were passive cements, and b) stylolites in host rock that formed as the veins grew in order to compensate for the volume added ...

Merino, E.

2006-01-01

415

Genesis of self-organized zebra textures in burial dolomites: Displacive veins, induced stress, and dolomitization  

OpenAIRE

The dolomite veins making up rhythmites common in burial dolomites are not cement infillings of supposed cavities, as in the prevailing view, but are instead displacive veins, veins that pushed aside the host dolostone as they grew. Evidence that the veins are displacive includes a) small transform-fault-like displacements that could not have taken place if the veins were passive cements, and b) stylolites in host rock that formed as the veins grew in order to compensate for the volume added ...

Merino, Enrique; Canals I Sabate?, A?ngels; Fletcher, R. C.

2006-01-01

416

Hoofbeats and Zebras: Neurodegenerative disorder presenting as a ‘first-episode’ of psychosis  

Science.gov (United States)

Neurodegenerative disorders can include diverse neuropsychiatric symptoms. Here we present a case referred to a ‘first-episode’ psychosis clinic with socio-occupational decline, auditory hallucinations and paranoid ideation who subsequently exhibited a rapid, severe cognitive and behavioral decline. The brain MRI findings of the patient have shown a progressive cortical atrophy prominent in the frontal lobes, due to a neurodegenerative disorder. PMID:21762843

Ozkan, Banu; Phutane, Vivek; Jonas, Elizabeth; Tek, Cenk; Srihari, Vinod

2011-01-01

417

Hoofbeats and zebras: neurodegenerative disorder presenting as a "first episode" of psychosis.  

Science.gov (United States)

Neurodegenerative disorders can include diverse neuropsychiatric symptoms. Here we present a case referred to a "first-episode" psychosis clinic with socio-occupational decline, auditory hallucinations and paranoid ideation who subsequently exhibited a rapid, severe cognitive and behavioral decline. The brain magnetic resonance imaging findings of the patient have shown a progressive cortical atrophy prominent in the frontal lobes due to a neurodegenerative disorder. PMID:21762843

Ozkan, Banu; Phutane, Vivek; Jonas, Elizabeth; Tek, Cenk; Srihari, Vinod

2011-01-01

418

Hoofbeats and Zebras: Neurodegenerative disorder presenting as a ‘first-episode’ of psychosis  

OpenAIRE

Neurodegenerative disorders can include diverse neuropsychiatric symptoms. Here we present a case referred to a ‘first-episode’ psychosis clinic with socio-occupational decline, auditory hallucinations and paranoid ideation who subsequently exhibited a rapid, severe cognitive and behavioral decline. The brain MRI findings of the patient have shown a progressive cortical atrophy prominent in the frontal lobes, due to a neurodegenerative disorder.

Ozkan, Banu; Phutane, Vivek; Jonas, Elizabeth; Tek, Cenk; Srihari, Vinod

2011-01-01

419

An experimental test of condition-dependent male and female mate choice in zebra finches  

OpenAIRE

In mating systems with social monogamy and obligatory bi-parental care, such as found in many songbird species, male and female fitness depends on the combined parental investment. Hence, both sexes should gain from choosing mates in high rather than low condition. However, theory also predicts that an individual's phenotypic quality can constrain choice, if low condition individuals cannot afford prolonged search efforts and/or face higher risk of rejection. In systems with mutual mate choic...

Holveck, Marie-jeanne; Geberzahn, Nicole; Riebel, Katharina

2011-01-01

420

What comes first, the zebra finch or the egg? Resource allocation during avian egg production  

OpenAIRE

Energy is an essential resource that all living organisms must balance. In vertebrates, very-low density lipoprotein (VLDL) particles play a key role in the transport of energy-rich lipids. During avian egg production, small yolk-targeted VLDL (VLDLy) particles are produced that can pass through the various layers of the ovary and are less susceptible to general metabolism, thereby preserving them for use by the developing ovarian follicles. To investigate how reproductive status and environm...

Salvante, Katrina Gotia

2006-01-01

421

Proximate control of avian sex allocation : a study on zebra finches  

OpenAIRE

Sex allocatie is de strategie van verschillende investering in mannelijke en vrouwelijke nakomelingen. Sex allocatie betreft zowel de investering in het relatieve aantal zoons en dochters, de geslachtsverhouding of sex ratio, als ook de relatieve investering in elke individuele zoon en dochter Zie: Nederlandse samenvatting

Engelhardt, Nikolaus Benedikt Baron Von

2004-01-01

422

Flavoprotein Autofluorescence Imaging of Visual System Activity in Zebra Finches and Mice  

OpenAIRE

Large-scale brain activity patterns can be visualized by optical imaging of intrinsic signals (OIS) based on activity-dependent changes in the blood oxygenation level. Another method, flavoprotein autofluorescence imaging (AFI), exploits the mitochondrial flavoprotein autofluorescence, which is enhanced during neuronal activity. In birds, topographic mapping of visual space has been shown in the visual wulst, the avian homologue of the mammalian visual cortex by using OIS. We here ...

Michael, Neethu; Bischof, Hans-joachim; Lo?wel, Siegrid

2014-01-01

423

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

OpenAIRE

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 a...

Ohms, Verena R.; Escudero, Paola; Lammers, Karin; Ten Cate, Carel

2012-01-01

424

Bill Redness Is Positively Associated with Reproduction and Survival in Male and Female Zebra Finches  

OpenAIRE

Sexual traits can serve as honest indicators of phenotypic quality when they are costly. Brightly coloured yellow to red traits, which are pigmented by carotenoids, are relatively common in birds, and feature in sexual selection. Carotenoids have been linked to immune and antioxidant function, and the trade-off between ornamentation and these physiological functions provides a potential mechanism rendering carotenoid based signals costly. Mutual ornamentation is also common in birds and can b...

Simons, Mirre J. P.; Briga, Michael; Koetsier, Egbert; Folkertsma, Remco; Wubs, Matthias D.; Dijkstra, Cor; Verhulst, Simon

2012-01-01

425

Ontogeny of Adaptive Antibody Response to a Model Antigen in Captive Altricial Zebra Finches  

OpenAIRE

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 ag...

Killpack, Tess L.; Karasov, William H.

2012-01-01

426

Sperm precedence in zebra finches does not require special mechanisms of sperm competition  

OpenAIRE

Competition between the spermatozoa of different males to fertilize the eggs of a single female acts as a selection pressure on the behaviour of males and females. However, quantitative predictions about behaviour fan only be made if the paternity consequences of different patterns of copulation are known. Because exhaustive empirical measurement of these consequences may be impractical, interest has centred on determining the mechanisms by which sperm competition occurs, knowledge of which m...

Colegrave, N.; Birkhead, T. R.; Lessells, C. M.

1995-01-01

427

Transgenerational effects on body size caused by early developmental stress in zebra finches  

OpenAIRE

The nutritional and social conditions that individuals experience during early development can have profound effects on their morphology, physiology, behaviour and life history. Experimental increases in brood size in birds can result in reduced offspring condition and survival, indicating that developmental deficits in enlarged broods have negative fitness consequences within the affected generation. To study long-term effects (i.e. transgenerational effects of developmental stress), we cond...

Naguib, Marc; Gil, Diego

2005-01-01

428

Neonatal nutrition, adult antioxidant defences and sexual attractiveness in the zebra finch.  

OpenAIRE

Early nutrition has recently been shown to have pervasive, downstream effects on adult life-history parameters including lifespan, but the underlying mechanisms remain poorly understood. Damage to biomolecules caused by oxidants, such as free radicals generated during metabolic processes, is widely recognized as a key contributor to somatic degeneration and the rate of ageing. Lipophilic antioxidants (carotenoids, vitamins A and E) are an important component of vertebrate defences against suc...

Blount, Jonathan D.; Metcalfe, Neil B.; Arnold, Kathryn E.; Surai, Peter F.; Devevey, Godefroy L.; Monaghan, Pat

2003-01-01

429

Gene duplication and fragmentation in the zebra finch major histocompatibility complex  

OpenAIRE

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 t...

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

2010-01-01

430

Species Shout-Outs From Abdul to Zebra: Encouraging Nonmajors to Communicate in the Biology Classroom  

OpenAIRE

In this learning activity, a simple verbal prompt was employed as a nonthreatening and engaging discussion starter for non-Biology majors in a biology class at a community college. By calling out the name of their favorite species, then relating new content to this organism, these “Species Shout-Outs” fostered enthusiasm among students by promoting engagement and creating relevance, all of which are important to improving higher education. This activity combined the elements of academi...

Colon, Christina P.

2012-01-01

431

De novo establishment of wild-type song culture in the zebra finch  

OpenAIRE

What sort of culture would evolve in an island colony of naive founders? This question cannot be studied experimentally in humans. We performed the analogous experiment using socially learned birdsong. Culture is typically viewed as consisting of traits inherited epigenetically, via social learning. However, cultural diversity has species-typical constraints1, presumably of genetic origin. A celebrated, if contentious, example is whether a universal grammar constrains syntactic diversity in h...

Feher, Olga; Wang, Haibin; Saar, Sigal; Mitra, Partha P.; Tchernichovski, Ofer

2009-01-01

432

Growth of a male Caracal kitten felis Caracal in the Mountain Zebra National Park  

Directory of Open Access Journals (Sweden)

Full Text Available Three caracal (lynx Fells caracal kittens, two females and a male were received from the Fish River area some 50 km north of Cradock, Republic of South Africa, on the 20th March 1980. These were found at the base of a dense Rhus erosa bush on the side of a hill and estimated at 14 days old based on the findings of Cade (1968 Int. Zoo Yb. 45 and Kralik (1967 Int. Zoo Yb. 132.

J. H Grobler

1982-11-01

433

Toxico-kinetic, chemical and radiological toxicity of uranium on zebra fish (Danio rerio)  

International Nuclear Information System (INIS)

This thesis explores the toxico-kinetic and toxicological aspects of uranium in fish. Uranium, appears to be highly bio accumulated and bio concentrated in fish. It spreads all through the whole organism. Nevertheless, its distribution is heterogeneous (gills and liver being the main sites of accumulation).From a toxicological point of view, we notice perturbations of the antioxidant system (inhibitions of hepatic Sod, Cat and G Px activities; depletion of total GSH) and of the cholinergic system (inhibition/over-activation of brain AChE). Genotoxic effects also appear in red blood cells, hepatocytes and gonad cells. The kinetics of these biochemical perturbations depend on the radiological activity of uranium, responses appearing earlier with increasing delivered activity. Histological effects (differing in types depending on delivered radiological activity) are also observed (in gills and muscles). (author)

434

17?-ESTRADIOL LEVELS IN MALE ZEBRA FINCH BRAIN: COMBINING PALKOVITS PUNCH AND AN ULTRASENSITIVE RADIOIMMUNOASSAY  

OpenAIRE

Local aromatization of testosterone into 17?-estradiol (E2) is often required for the physiological and behavioral actions of testosterone. In most vertebrates, aromatase is expressed in a few discrete brain regions. While many studies have measured brain aromatase mRNA or activity, very few studies have measured brain E2 levels, particularly in discrete brain regions, because of technical challenges. Here, we used the Palkovits punch technique to isolate 13 discrete brain nuclei from adult ...

Charlier, Thierry D.; Po, Kelvin W. L.; Newman, Amy E. M.; Shah, Amit H.; Saldanha, Colin J.; Soma, Kiran K.

2010-01-01

435

A re-assessment of the avifauna of the Mountain Zebra National Park  

Directory of Open Access Journals (Sweden)

Full Text Available Based on all published records, together with the original data for the southern African bird atlas, the current Birds in Reserves Project and our records on field trips, 257 bird species have been reliably recorded from MZNP. We have assessed the current status of all species, in relation to the recent expansion of the park and other changes which may be a consequence of management practices. No birds of national conservation concern are breeding residents in the park, and some species are periodic or irregular visitors. Nevertheless, the park is important for the conservation of representatives of the Karoo avifauna, and the diversity of birdlife present should be highlighted to attract visitors with a special interest in birding.

P.E. Hilley

2005-06-01

436

Maternal developmental stress reduces reproductive success of female offspring in zebra finches  

OpenAIRE

Environmental factors play a key role in the expression of phenotypic traits and life-history decisions, specifically when they act during early development. In birds, brood size is a main environmental factor affecting development. Experimental manipulation of brood sizes can result in reduced offspring condition, indicating that developmental deficits in enlarged broods have consequences within the affected generation. Yet, it is unclear whether stress during early development can have fitn...

Naguib, Marc; Nemitz, Andrea; Gil, Diego

2006-01-01

437

Horses and Zebras: complex cardiac anatomy in a patient with out-of-hospital cardiac arrest  

OpenAIRE

This case report describes a woman presenting after out-of-hospital cardiac arrest with several cardiac anomalies, including a form fruste of Ebstein’s anomaly complicated by a large tricuspid valve vegetation. On autopsy, she proved to have unstable plaques in epicardial vessels that likely caused arrhythmic sudden cardiac death, a reminder that even in the presence of rare anomalies, common things are common.

Brown, Samuel M.; Miller, Dylan V.; Vezina, Daniel; Dean, Nathan C.; Grissom, Colin K.

2011-01-01

438

Horses (Equus caballus) discriminate body odour cues from conspecifics.  

Science.gov (United States)

Knowledge about social recognition and memory in animals can help us to determine appropriate management and husbandry techniques. In this study, we used a habituation-discrimination procedure to investigate the ability of horses (Equus caballus) to distinguish between the body odour samples of unfamiliar conspecifics. To pick up body odour, we rubbed material on the coat of horses and presented these unknown body odours to 16 different conspecifics of the same sex and similar age. The test consisted of two successive two-min presentations of a sample from one individual (e.g. individual 'A') and a simultaneous presentation of samples from individual 'A' and a novel individual (e.g. individual 'B') during a final third presentation. The results showed that horses, regardless of sex, decreased the time they spent investigating conspecific body odour across the initial two presentations-demonstrating habituation. In the final presentation, the results demonstrated successful discrimination of the previously experienced odour because horses investigated the novel olfactory sample ('B') significantly more than the pre-exposed sample ('A'). Taken together, these findings suggest, for the first time, that horses are able to discriminate two stimuli derived from body odours of unfamiliar conspecifics over short period of time. PMID:24305997

Péron, F; Ward, R; Burman, O

2014-07-01

439

An investigation of colour discrimination with horses (Equus caballus).  

Science.gov (United States)

The ability of four horses (Equus caballus) to discriminate coloured (three shades of blue, green, red, and yellow) from grey (neutral density) stimuli, produced by back projected lighting filters, was investigated in a two response forced-choice procedure. Pushes of the lever in front of a coloured screen were occasionally reinforced, pushes of the lever in front of a grey screen were never reinforced. Each colour shade was randomly paired with a grey that was brighter, one that was dimmer, and one that approximately matched the colour in terms of brightness. Each horse experienced the colours in a different order, a new colour was started after 85% correct responses over five consecutive sessions or if accuracy showed no trend over sessions. All horses reached the 85% correct with blue versus grey, three horses did so with both yellow and green versus grey. All were above chance with red versus grey but none reached criterion. Further analysis showed the wavelengths of the green stimuli used overlapped with the yellow. The results are consistent with histological and behavioural studies that suggest that horses are dichromatic. They differ from some earlier data in that they indicate horses can discriminate yellow and blue, but that they may have deficiencies in discriminating red and green. PMID:18359171

Blackmore, T L; Foster, T M; Sumpter, C E; Temple, W

2008-07-01

440

Trained Quantity Abilities in Horses (Equus caballus: A Preliminary Investigation  

Directory of Open Access Journals (Sweden)

Full Text Available Once believed to be a human prerogative, the capacity to discriminate between quantities now has also been reported in several vertebrates. To date, only two studies investigated numerical abilities in horses (Equus caballus but reported contrasting data. To assess whether horses can be trained to discriminate between quantities, I have set up a new experimental protocol using operant conditioning. One adult female was trained to discriminate between 1 and 4 (Test 1 in three different conditions: non-controlled continuous variables (numerical and continuous quantities that co-vary with number are simultaneously available, 50% controlled continuous variables (intermediate condition, and 100% controlled continuous variables (only numerical information available. The subject learned the discrimination in all conditions, showing the capacity to process numerical information. When presented with a higher numerical ratio (2 vs. 4, Test 2, the subject still discriminated between the quantities but its performance was statistically significant only in the non-controlled condition, suggesting that the subject used multiple cues in presence of a more difficult discrimination. On the whole, the results here reported encourage the use of this experimental protocol as a valid tool to investigate the capacity to process numerical and continuous quantities in horses in future research.

Maria Elena Miletto Petrazzini

2014-07-01