Wyniki wyszukiwania

1

Drobnoustroje - wazne ogniwo ekosystemu

100%

Wojcik D.

Chrońmy Przyrodę Ojczystą

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1992

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tom 48

|

nr 3

62-68

2

Gospodarka współdzielenia z perspektywy przedsiębiorców sektora turystycznego

72%

Czernek K., Wojcik D.

Handel Wewnętrzny

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2017

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tom 63

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nr 3

Gospodarka współdzielenia (sharing economy) od kilku lat cieszy się rosnącym zainteresowaniem badaczy, jednak wciąż stanowi obszar słabo rozpoznany, wymagający dalszych badań. Pojawienie się nowych graczy na rynku, oferujących alternatywne formy podróżowania z wykorzystaniem platform technologicznych, może budzić niepewność wśród przedsiębiorstw, świadczących swoje profesjonalne usługi w sektorze turystycznym. Celem artykułu jest zatem przedstawienie wyników badań na temat postrzegania gospodarki współdzielenia przez przedsiębiorców z sektora turystycznego w zakresie następujących aspektów: 1) czy omawiana koncepcja jest im znana, 2) czy dostrzegają realizowane w jej ramach aktywności, zarówno w sektorze turystycznym, jak i na obszarach turystycznych, prowadzonej przez siebie działalności gospodarczej. Wnioski sformułowano na podstawie eksploracyjnych, indywidualnych wywiadów pogłębionych, przeprowadzonych wśród przedsiębiorców w każdym z polskich województw.

3

Zanieczyszczenie wod doplywajacych do stawow w dorzeczu gornej Wisly

72%

Wrobel S., Wojcik D.

Zeszyty Naukowe Akademii Rolniczej we Wrocławiu. Zootechnika

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1992

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tom 37

203-215

4

Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik

Gonad maturity in female Chinese mitten crab Eriocheir sinensis from the Southern Baltic Sea – the first description of ovigerous females and the embryo developmental stage

72%

Wojcik D., Normant M.

Oceanologia

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2014

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tom 56

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nr 4

5

Brainslices-image sharing for neuroscience

58%

Kowalski J., Majka P., Puscian A., Wojcik D.

Acta Neurobiologiae Experimentalis

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2015

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tom 75

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nr Supl.

AIM: Images of brain tissue are common outcome of a great number of neuroscience experiments; however, their impact on scientific development is limited since they are usually not published directly. Internet technology facilitates making the images available online, nonetheless, raw image files of good quality are very large and therefore inconvenient to provide and analyze online directly. There is still no convenient way to share annotated images of neuroscientific specimens. To fill that gap we developed BrainSlices software – a user-friendly tool dedicated for that purpose. METHODS: The software is built in the client-server model and consist of a web application at the client side, and server software running on a Linux system. Thanks to this design there is no need for installation and the only thing a BrainSlices user must do is to open a website. This approach also makes BrainSlices a cross-platform tool. Handling of large images is solved with image pyramid technique. RESULTS: We used BrainSlices software to set up an online repository (http://brainslices.org) of annotated high quality images of brain tissue. The repository combines the power of the image pyramid technique with convenience of image upload. Every image can be easily annotated with exhaustive metadata which facilitate search. The user interface of the repository and the provided facilities were developed with typical neuroscience use in mind. Every image receives a unique identifier and a permalink which allows direct access and citing. CONCLUSION: We provide the community with a user friendly tool for multiple image storage, viewing, sharing, and annotation. The tool may be used to store one’s own collection of slice images to share high quality specimen images with collaborators, to share them with the whole community, or to provide the images online as supplementary material for publications.

6

Anomalous decay of power in high frequency oscillations (HFO) with distance from the source

58%

Gorski T., Hunt M., Kasicki S., Wojcik D.

Acta Neurobiologiae Experimentalis

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2015

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tom 75

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nr Supl.

BACKGROUND AND AIMS: Brain electric potentials recorded extracellularly are generated by transmembrane currents leaving and entering active neurons. Electric charge conservation requires that these currents are balanced in every cell separately, which implies a dipolar structure of sources. We previously reported results suggesting a monopolar structure of high-frequency oscillations (135–165 Hz) generated in nucleus accumbens (NAc) which seems to be inconsistent with known physics. The goal of this study is to find out through numerical simulations if the specific morphology and spatial distribution of accumbal neurons can shed light on this paradox. METHODS: Multi-compartment models of medium spiny neuron (MSN) from NAc (based on ModelDB, accession nr 112834) were used for simulations in the NEURON simulator. We computed transmembrane activity of a population of MSNs in response to different oscillating stimuli. The sum of extracellular potentials generated by individual cells in selected points in space simulated the local field potential. Potentials were filtered in different bands to study the decay of the power with distance from the source. RESULTS: We show that the observed increased power in the HFO band can be explained by coherent spiking of population of MSNs. In all the studied frequency bands and in all directions we observe asymptotic decay with distance close to what is expected from dipolar sources (1/r^2). However, over short spatial scales, the scaling does get closer to monopolar decay (1/r). These results are compared with reevaluated decay data from Hunt et al. (2010). CONCLUSIONS: Since the numerical results are consistent with the experimental results it seems that the specific morphology and distribution of MSNs within NAc are sufficient to explain the observed anomalous decay of HFO power over intermediate distances. There is no need for consideration of additional mechanisms, for example, capacitive effects of the extracellular space.

7

A method for in vitro testing strawberry susceptibility to Verticillium wilt

58%

Sowik I., Michalczuk L., Wojcik D.

Journal of Fruit and Ornamental Plant Research

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2008

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tom 16

111-121

8

Wpływ doświetlania diodami elektroluminescencyjnymi (LED) na morfologię, zawartość chlorofilu oraz aktywność fotosyntetyczną sadzonek truskawki (Fragaria × ananassa DUCH.)

58%

Wojcik D., Markiewicz M., Matysiak B., Sowik I.

Zeszyty Naukowe Instytutu Ogrodnictwa

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2021

|

tom 29

9

Impact of Chinese mitten crab Eriocheir sinensis on blue mussel Mytilus edulis trossulus – laboratory studies of claw strength, handling behavior, consumption rate, and size selective predation

58%

Wojcik D., Normant M., Dmochowska B., Fowler A.

Oceanologia

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2015

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tom 57

|

nr 3

10

Ocena mozliwosci zastosowania mikrozbiornikow w ochronie wod powierzchniowych przed splywami zwiazkow azotu i fosforu

58%

Fiszer J., Jarzabek A., Schmager M., Wojcik D.

Zeszyty Naukowe Akademii Rolniczej w Krakowie. Sesja Naukowa

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1992

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tom 32

149-166

11

Epibiotic mites associated with the invasive Chinese mitten crab Eriocheir sinensis – new records of Halacaridae from Poland

58%

Normant M., Zawal A., Chatterjee T., Wojcik D.

Oceanologia

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2013

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tom 55

|

nr 4

12

Evidence for regionally specific changes in high-frequency oscillations after injection of ketamine in freely moving rats

58%

Hunt M., Falinska M., Wojcik D., Kasicki S.

Acta Neurobiologiae Experimentalis

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2009

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tom 69

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nr 3

We have shown previously that the NMDAR antagonists ketamine and MK-801 enhance high-frequency oscillations (140– 180 Hz, HFO) in the rat nucleus accumbens (NAc). However, it is not known whether NMDAR antagonists can modify HFO recorded in structures outside the NAc. Thus we have examined the effect of a single subanesthetic dose of ketamine (25 mg/kg) on oscillatory activity in local fi eld potentials recorded in the neuroanatomically related dorsal striatum and in the hippocampus, where spontaneous high-frequency oscillations (ripples) have been well described. We used both monopolar and bipolar recordings to evaluate oscillatory activity recorded at baseline and after injection of ketamine. In monopolar recordings ketamine-induced increases in the power of HFO were present in all structures, although the power was always substantially larger in the NAc. Bipolar recordings, known to remove common-mode input, were used in an attempt to more precisely localise the source of HFO. In all cases ketamine-induced HFO were still present in the signals recorded from the NAc, but not from the dorsal striatum or hippocampus. Notably, spontaneous sharp-wave ripples also remained in the bipolar signal from the hippocampus. In a separate study of the depth-profi le analysis of oscillatory activity we found the power of HFO was substantially larger in areas closest to the NAc. These fi ndings suggest that ketamine may produce some regionally specifi c changes in HFO.

13

Ocena wzrostu i stabilności genetycznej agrestu (Ribes grossularia L.) rozmnażanego in vitrooraz ex vitro

58%

Kucharska D., Wojcik D., Trzewik A.

Biuletyn Instytutu Hodowli i Aklimatyzacji Roślin

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2020

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nr 291

14

How does the firing rate of superior colliculus neurons correlate with image of brain activity?

51%

Moloch G., Wypych M., Foik A., Wojcik D., Waleszczyk W. J.

Acta Neurobiologiae Experimentalis

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2011

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tom 71

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nr S

Firing rate of the majority of cells from superficial layers of cat’s superior colliculus (SC) is modulated in relatively long time scale. Such changes in spike generation do not depend on presented visual stimuli. To investigate whether these modulations of firing rate are related to changes in cortical states we analyzed visually evoked activity of SC neurons and electrocorticogram (ECoG) simultaneously recorded from the occipital lobe. The extracellular single unit activity was recorded from superficial, retinorecipient layers of the SC in anaesthetized and paralyzed cats. The level of anaesthesia was kept constant during recordings. As a visual stimulus we used light spot moving with different, randomly selected velocities. On average, each neuron was recorded continuously for 1 hour. Simultaneously we recorded ECoG from contralateral area 18 close to representation of the area centralis. The power spectra of ECoG data were calculated using fast Fourier transform in sliding windows. The firing rate of a given neuron was calculated in the same time windows and then correlated with the power in a given frequency band of ECoG. Most of the observed firing rate modulations were on the time scale from several to tens of minutes and were positively or negatively correlated with the changes in ECoG power in the band between 0.5 to 8 Hz, sometimes even to 13 Hz. For some neurons we also observed correlations between firing rate and power in the beta band (13 – 30 Hz) of ECoG and in most cases those correlations were opposite to correlations in lower bands. Rarely we observed also the relation between firing rate and the power of gamma band. Fast modulations of firing rate were not correlated with changes of ECoG power in any band. These results show that responsiveness of particular subpopulations of collicular neurons is differently related to the global state of brain activity. Supported by Polish MSHE grant N N303 070234.

15

Separating dynamics of different cell populations from multielectrode signals

51%

Wojcik D., Potworowski J., Glabska H., Majka P., Leski S.

Acta Neurobiologiae Experimentalis

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2011

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tom 71

|

nr S

Local field potentials (LFP), low-frequency part of extracellular electric potentials, seem to reflect dendritic processing of incoming activity to neural populations. Long-range nature of electric field leads to correlations even between remote recordings showing sources from millimeters away which complicates analysis of LFP. To get more insight it is convenient whenever possible to look for current sources of the potentials or to decompose the signals into meaningful components using statistical techniques. In Łęski and coauthors (2010) we have combined inverse current source density method with independent component analysis (ICA) to decompose 140 recordings in rat forebrain obtaining physiologically meaningful components across a group of seven animals. To find out what can be really observed with such an approach experimentally we simulated local field potentials generated in a single cortical column in a model of 3560 cells with non-trivial morphologies. Having both the current source density (CSD) and LFP generated by twelve cortical populations included we compared it with independent components obtained in the decomposition of data generated by the whole network. We assumed a set of potential measurements on a regular grid, low-pass filtered it temporally under 500 Hz, reconstructed the sources using kernel current source density and performed the ICA. We found that the recorded evoked activity was dominated by two populations of pyramidal neurons, which were well separated by ICA. Other populations could not be clearly distinguished in the simulated potentials nor in the ICA. Supported by grants POIG.02.03.00-00-003/09, POIG.02.03.00-00-018/08.

16

Beyond the PSTH: point process modeling of spike trains

51%

Wojcik D., Mochol G., Wypych M., Waleszczyk W., Wrobel A.

Acta Neurobiologiae Experimentalis

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2009

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tom 69

|

nr 3

A prerequisite for a quantitative theory of neural coding is adequate description of spike trains. Fifty years ago it was understood that the probability to generate a spike at a given time from the stimulus onset – the post-stimulus time histogram (PSTH) – brings in useful information adding to the mean number of spikes in the trial. Today there is a growing consensus that one must go beyond the PSTH building more complex point process models of neural activity which can account, for basic physiological properties of spike fi ring, e.g. for the refractory properties or for adaptation mechanisms of the cell. We shall present some basic concepts of the point process theory in the context of the spike trains and present a simple method of estimation of a class of second order processes for stimulus-evoked activity. We will illustrate the results with an analysis of sample data from the cat superior colliculus. Supported by grants N401 146 31/3239 and 46/N-COST/2007/0.

17

Określenie procentowego udziału kwasów tłuszczowych w tłuszczu mleka klaczy

51%

Kacprzak S., Pietrzak-Fiecko R., Felkner-Pozniakowska B., Galgowska M., Wojcik D.

Bromatologia i Chemia Toksykologiczna

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2012

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tom 45

|

nr 3

18

U piekarzy za Odra

51%

Bryla R., Wojcik D.

Cukiernictwo i Piekarstwo

|

2003

|

tom 07

|

nr 03

14

19

Badania przydatności niektórych surowców do produkcji dietetycznego chleba skrobiowego

51%

Bartnik M., Wojcik D.

Przegląd Piekarski i Cukierniczy

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1983

|

tom 31

|

nr 1

20

Delineation of brain structures in the Monodelphis domestica opossum brain

44%

Chlodzinska N., Majka P., Banasik T., Djavadian R. L., Weglarz W. P., Wojcik D., Turlejski K.

Acta Neurobiologiae Experimentalis

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2013

|

tom 73

|

nr Suppl.1

The Monodelphis opossum became an important laboratory animal and is often used in biomedical research. However, data on the brain anatomy are scarce and there is no reliable brain anatomy reference. The aim of this study is to present neuroanatomical delineation of basic brain structures. Data which served for construction of the 3-dimensional atlas were magnetic resonance images (MRI) and stained brain sections. MRI was obtained 48 h after perfusion of the animal with 4% paraformaldehyde and gadotheridol contrast (ProHance 20:1 v:v). The second MRI was performed 30 days after perfusion of the same animal. Both MRIs were aquired using Bruker Biospin system with voxel reolution of 50 µm3. For Nissland myelin staining, coronal brain sections were cut in cryostat at 40 µm thickness. To minimize tissue deformation, sections were transferred from the cutting blade to slides using the Tape-Transfer System. Then brain sections stained either with Nissl or for myelin were imaged with a high resolution scanner and were transformed to three-dimensional form. By superimposing all three-dimensional data, several brain structures were delineated, e.g., the olfactory bulb, cerebral cortex, hippocampus, white matter and other. Supported by grant from the Polish Ministry of Regional Development POIG.02.03.00-00-003/09.

Ograniczanie wyników

Drobnoustroje - wazne ogniwo ekosystemu

Gospodarka współdzielenia z perspektywy przedsiębiorców sektora turystycznego

Zanieczyszczenie wod doplywajacych do stawow w dorzeczu gornej Wisly

Gonad maturity in female Chinese mitten crab Eriocheir sinensis from the Southern Baltic Sea – the first description of ovigerous females and the embryo developmental stage

Brainslices-image sharing for neuroscience

Anomalous decay of power in high frequency oscillations (HFO) with distance from the source

A method for in vitro testing strawberry susceptibility to Verticillium wilt

Wpływ doświetlania diodami elektroluminescencyjnymi (LED) na morfologię, zawartość chlorofilu oraz aktywność fotosyntetyczną sadzonek truskawki (Fragaria × ananassa DUCH.)

Impact of Chinese mitten crab Eriocheir sinensis on blue mussel Mytilus edulis trossulus – laboratory studies of claw strength, handling behavior, consumption rate, and size selective predation

Ocena mozliwosci zastosowania mikrozbiornikow w ochronie wod powierzchniowych przed splywami zwiazkow azotu i fosforu

Epibiotic mites associated with the invasive Chinese mitten crab Eriocheir sinensis – new records of Halacaridae from Poland

Evidence for regionally specific changes in high-frequency oscillations after injection of ketamine in freely moving rats

Ocena wzrostu i stabilności genetycznej agrestu (Ribes grossularia L.) rozmnażanego in vitrooraz ex vitro

How does the firing rate of superior colliculus neurons correlate with image of brain activity?

Separating dynamics of different cell populations from multielectrode signals

Beyond the PSTH: point process modeling of spike trains

Określenie procentowego udziału kwasów tłuszczowych w tłuszczu mleka klaczy

U piekarzy za Odra

Badania przydatności niektórych surowców do produkcji dietetycznego chleba skrobiowego

Delineation of brain structures in the Monodelphis domestica opossum brain