Maria Gytkjær Nielsen

Ms. Maria Gytkjær Nielsen


Research Focus & Metrics

Academic Career Length

3Years (2024-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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30 September 2024 in Animals
Verified
Journal Article
Open access
PDF file
SLSilje Marquardsen Lund
Silje Marquardsen Lund
JNJonas Nielsen
Jonas Nielsen
FGFrej Gammelgård
Frej Gammelgård
MNMaria Gytkjær Nielsen
Maria Gytkjær Nielsen
TJTrine Hammer Jensen
Trine Hammer Jensen
Cino PertoldiCino Pertoldi
Cino Pertoldi
This study investigates the possibility of using machine learning models created in DeepLabCut and Create ML to automate aspects of behavioral coding and aid in behavioral analysis. Two models with different capabilities and complexities were constructed and compared to a manually observed control period. The accuracy of the models was assessed by comparison with manually scoring, before being applied to seven nights of footage of the nocturnal behavior of two African elephants (Loxodonta africana). The resulting data were used to draw conclusions regarding behavioral differences between the two elephants and between individually observed nights, thus proving that such models can aid researchers in behavioral analysis. The models were capable of tracking simple behaviors with high accuracy, but had certain limitations regarding detection of complex behaviors, such as the stereotyped behavior sway, and displayed confusion when deciding between visually similar behaviors. Further expansion of such models may be desired to create a more capable aid with the possibility of automating behavioral coding.

28 August 2024 in Preprints.org
Verified
Preprint
Open access
PDF file
SLSilje Marquardsen Lund
Silje Marquardsen Lund
JNJonas Nielsen
Jonas Nielsen
FGFrej Gammelgård
Frej Gammelgård
MNMaria Gytkjær Nielsen
Maria Gytkjær Nielsen
TJTrine Hammer Jensen
Trine Hammer Jensen
Cino PertoldiCino Pertoldi
Cino Pertoldi
This study investigates the possibility of using machine learning models created in DeepLabCut and Create ML to automate aspects of behavioral coding and aid in behavioral analysis. Two models with different capabilities and complexities were constructed and compared to a manually observed control period. The accuracy of the models was assessed before being applied to 7 nights of footage of the nocturnal behavior of two African elephants (Loxodonta africana). The resulting data was used to draw conclusions regarding behavioral differences between the two elephants and between individually observed nights, thus proving that such models can aid researchers in be-havioral analysis. The models were capable of tracking simple behaviors with high accuracy, but had certain limitations regarding detection of complex behaviors, such as the stereotyped behavior sway, and displayed confusion when deciding between visually similar behaviors. Further expansion of such models may be desired to create a more capable aid with the possibility of automating behavioral coding.

20 July 2024 in Animals
Verified
Journal Article
Open access
PDF file
SLSilje Marquardsen Lund
Silje Marquardsen Lund
JJJohanne Holm Jacobsen
Johanne Holm Jacobsen
MNMaria Gytkjær Nielsen
Maria Gytkjær Nielsen
MFMarie Ribergaard Friis
Marie Ribergaard Friis
NNNatalie Hvid Nielsen
Natalie Hvid Nielsen
Cino PertoldiCino Pertoldi
Cino Pertoldi
Interest in virtual fencing has increased due to its flexibility for agriculture and rewilding. However, systems like Nofence© require large financial investments, and the need for individual collars complicates large-scale use. If cattle herds maintain cohesive groups around leading individuals, fewer collars could be used, thereby enhancing cost efficiency. This study investigates the pattern in spatial distribution in a herd of 17 Angus cows on Fanø in Denmark with GPS locations, using a Nofence© system. The aim of this paper is to determine how individuals position themselves in a herd, spatially, and identify a pattern in ranks. The method used in this study examines the distances between an individual to the rest of the herdmates using nearest neighbour and descriptive statistics. Contrary to expectations, this study did not reveal a distinct pattern in herd distribution. While some tendencies in spatial distribution patterns were observed, only a low concordance could be found (W=0.15,p<0.001), indicating great variability in the cattle’s ranks. A cumulative curve of the ranks estimated over the entire periods, however, allowed a rough estimation of the hierarchy and allowed identification of the highest-ranked cows, making the use of a cumulative curve a possible solution to finding the high-ranked cows. This research underscores the complexity of cattle social structures and highlights the need for extended observation periods and alternative methodologies to enhance the cost-effectiveness and scalability of virtual fencing in agricultural and rewilding contexts.

2 April 2024 in Preprints.org
Verified
Preprint
Open access
PDF file
SLSilje Marquardsen Lund
Silje Marquardsen Lund
JJJohanne Holm Jacobsen
Johanne Holm Jacobsen
MNMaria Gytkjær Nielsen
Maria Gytkjær Nielsen
MFMarie Ribergaard Friis
Marie Ribergaard Friis
NNNatalie Hvid Nielsen
Natalie Hvid Nielsen
Cino PertoldiCino Pertoldi
Cino Pertoldi
The interest in virtual fencing, as opposed to traditional physical barriers, has increased since it makes it easier to move the boundaries of animal enclosures for agricultural and rewilding purposes. Despite this, the implementation of virtual fence systems, such as the Nofence© system, requires large financial investments. The necessity of individual collars also makes it more difficult to implement this system on a larger scale. If a herd of cattle tend to maintain cohesive social groups around dominant individuals, it might be possible to use fewer collars thereby making the system more cost efficient. This study investigates the pattern in spatial distribution in a herd of 17 Angus cows on Fanø in Denmark with GPS locations, using a Nofence© system. The aim of this paper is to determine how individuals position themselves in a herd, spatially, and identify a pattern in ranks. The method used in this study examines the distances between an individual to the rest of the herd mates using nearest neighbour and distribution plots. Contrary to the expectations, this study did not show a distinct pattern in herd distribution. While some tendencies in spatial distribution patterns were observed, only a low concordance could be found (W=0.15,p=3.02e−16). Therefore, interactions among individuals should be considered in future studies, rather than only investigating the herd as one unit. A cumulative curves of the ranks estimated over the entire periods allowed however a rough estimation of the hierarchy and allowed the identification of the highest ranked cows. Therefore it might be possible to use fewer collars if the high ranked cows are discovered, but the estimation of the hierarchy will require a period of observation overall several days as the hierarchical positions are fluctuating too much from days to days. Therefore the cumulative rank curves seems to be a valid solution.

8 April 2024 in Preprints.org
Verified
Preprint
Open access
PDF file
CJCamilla Elita Bach Jensen
Camilla Elita Bach Jensen
JBJacob T Bundesen
Jacob T Bundesen
MSMajbrit Winding Rindom Sørensen
Majbrit Winding Rindom Sørensen
MGMikkel Trankjær Gudmann
Mikkel Trankjær Gudmann
PKPeter Kristian Kyed
Peter Kristian Kyed
JPJuan Olvido Perea-Garcia
Juan Olvido Perea-Garcia
The social- and self-directed behaviours of two golden lion tamarins (Leontopithecus rosalia) was investigated while having residence in the tropical house of Aalborg Zoo, Denmark. The behaviour of the female had been distinct from the male since 2018. Despite several diagnostic examinations and medicinal treatments, the cause of the aberrant and apparently stereotypical behavioural patterns remained undetermined, which initiated this study. The pair were recorded throughout a predetermined observation period and these recordings were analysed to illuminate the behaviours of the individuals. The results showed that there were differences in the type, frequency, and durations of both social- and self-directed behaviours between the sick female and the healthy male. The female expressed both social- and self-directed behaviours more frequently and for longer durations, while the male were more socially reserved and did not engage in social behaviours as frequently. Furthermore, subsequent necropsy of the female revealed uro-genital disease.