Human Analogue Safe Haven Effect of the Owner : Behavioural and Heart Rate Response to Stressful Social Stimuli in Dogs

The secure base and safe haven effects of the attachment figure are central features of the human attachment theory. Recently, conclusive evidence for human analogue attachment behaviours in dogs has been provided, however, the owner’s security-providing role in danger has not been directly supported. We investigated the relationship between the behavioural and cardiac response in dogs (N = 30) while being approached by a threatening stranger in separation vs. in the presence of the owner, presented in a balanced order. Non-invasive telemetric measures of heart rate (HR) and heart rate variability (HRV) data during the threatening approaches was compared to periods before and after the encounters. Dogs that showed distress vocalisation during separation (N = 18) and that growled or barked at the stranger during the threatening approach (N = 17) were defined as behaviourally reactive in the given situation. While characteristic stress vocalisations were emitted during separations, the absence of the owner did not have an effect on dogs’ mean HR, but significantly increased the HRV. The threatening approach increased dogs’ mean HR, with a parallel decrease in the HRV, particularly in dogs that were behaviourally reactive to the encounter. Importantly, the HR increase was significantly less pronounced when dogs faced the stranger in the presence of the owner. Moreover, the test order, whether the dog encountered the stranger first with or without its owner, also proved important: HR increase associated with the encounter in separation seemed to be attenuated in dogs that faced the stranger first in the presence of their owner. We provided evidence for human analogue safe haven effect of the owner in a potentially dangerous situation. Similarly to parents of infants, owners can provide a buffer against stress in dogs, which can even reduce the effect of a subsequent encounter with the same threatening stimuli later when the owner is not present

Qualitative Behaviour Assessment of dogs in the shelter and home environment and relationship with quantitative behaviour assessment and physiological responses

Qualitative Behaviour Assessment (QBA) was utilised to examine the behavioural expression of dogs in different housing environments and the results were compared to measurements of quantitative behaviour and physiology. Firstly, quantitative behavioural and physiological differences were investigated between dogs in 3 housing environments (short-term shelter confinement, ≤ 4 days, n = 10; long-term shelter confinement, > 30 days, n = 9; and domestic living situations, n = 10). Each dog’s behaviour was recorded over a 4 h period using an ethogram consisting of 21 behaviour categories. Dogs in both short (SD) and long (LD) term confinement displayed higher frequencies of paw-lifting (P < 0.001), displacement behaviour (digging and/or drinking P < 0.01), vocalisation (P < 0.05) and locomotory activity (P < 0.001) compared to dogs maintained as family pets (PD). Salivary cortisol concentrations did not differ amongst groups (H = 0.55, P = 0.76). Secondly, quantitative behaviour and QBA were combined to investigate differences among these same 29 dogs when filmed for 1 min in both their Home Environment and a standardised Novel Environment. QBA of these video clips was made by 10 observers utilising Free-Choice-Profiling methodology. Generalised Procrustes Analysis was used to calculate a consensus profile and three main dimensions of dog expression in both Environments. The observers repeated dog scores on these dimensions with high accuracy (P < 0.001). Observers perceived dogs as more ‘relaxed/content’ in the Home Environment (H = 17.86, P < 0.0001), and more ‘calm/relaxed’ in the Novel Environment (H = 13.58, P < 0.001), than SD and LD dogs. In the Novel Environment, LD dogs were perceived as more ‘inquisitive/curious’ (H = 5.97, P < 0.05), and SD dogs as more ‘curious/cautious’ (H = 6.82, P < 0.05), than the other groups. Quantitative assessment of the 1 min Home and Novel Environment video clips were analysed using Principle Component Analysis (PCA), generating two main factors explaining 88% and 76% of the variation respectively. PCA factor 1 (‘rest’) and QBA Dimension 1 (‘relaxed/content’) correlated (P < 0.0001) in the Home Environment’. In the Novel Environment PCA factor 1 (‘stand’, ‘sniff’) correlated with QBA Dimension 1 (‘clam/relaxed’) and PCA factor 2 (‘sniff’, ‘walk’) correlated with QBA Dimension 2 (‘curious/inquisitive’). There was no correlation between QBA dimensions and cortisol concentrations. In sum, these results indicate that a combined quantitative/qualitative assessment facilitates the interpretation of behavioural variances resulting from housing differences and supports utilising QBA for the assessment of dog behavioural expression

Pregled znanstvenih napredaka u učinskoj elektronici usmjerenih ka osiguravanju efikasnog rada i dužeg životnog vijeka PEMgorivih ćelija

This article focuses on the main issues that affect the lifetime and performance of proton-exchange membrane fuel cells. The short lifespans of these fuel cells represent a barrier to their massive commercialization and usage in mobile and stationary applications. As fuel cell is a very complex system, a lot of knowledge of different areas is required, such as chemistry, electricity and mechanics, in order to completely understand its operation and all the problems that can occur during it. It is for this reason that an interdisciplinary approach needs to be taken when designing fuel-cell energy systems. This paper focuses on identifying and solving those issues that negatively affect the lifetime and performance of fuel cells. It is hoped that this article would be a valuable aid for power electronics’ researchers and engineers for better understanding the presented issues and a useful guide for solving them with the use of proper power electronic-devices. Initially, the basic operation and structure of a proton-exchange membrane fuel cell is explained. Three main issues that can occur during operation of a mobile or stationary fuel cell energy system are pointed out and discussed in details, on the basis of the state-of-the-art on fuel cell technology. These issues are poor water management, reactant gas starvation and fuel cell current ripple. This article provides answers as to why they occur, how they affect the fuel cell, how they can be mitigated, and what are the future trends within this research field.Članak se osvrće na ključna pitanja koja utječu na vrijeme rada i performanse gorivih ćelija s polimernom membranom kao elektrolitom. Kratak životni vijek gorivih ćelija takve vrste prepreka je njihovoj komercijalizaciji i masovnoj upotrebi u mobilnim i stacionarnim stanicama. Budući da su gorive ćelije komplicirani sustavi potrebno je znanje iz raznih područja kemije, elektrotehnike i mehanike da bi se u potpunosti mogao razumjeti njihov način rada i problemi koji se događaju. Upravo je zbog toga multidisciplinarni pristup nužnost pri razvoju sustava koji koriste gorive ćelije. Ovaj je članak usmjeren prema identifikaciji i rješavanju onih problema koji negativno utječu na životni vijek i performanse gorivih ćelija. Autori se nadaju da će se članak pokazati kao korisna pomoć i vodič istraživačima i inženjerima u domeni učinske elektronike pri susretu s navedenim problemima. Objašnjen je način rada i struktura gorive ćelije s polimernom membranom kao elektrolitom. Izložena su, i diskutirana do u detalje, tri glavna problema sa stajališta trenutačnih spoznaja u području učinske elektronike. Ti problemi su: loše upravljanje vodom, nestanak reaktantnog plina i strujni trzaji u gorivim ćelijama. Objašnjeno je zašto se ovi problemi događaju, kako utječu na gorivu ćeliju, kako ih se može spriječiti i koje su buduće perspektive istraživanja