Guard Stage Research Articles

Progress Toward Transition Edge Sensor Arrays With On-Chip Thermal Stabilization

Electrothermal feedback in a transition edge sensor (TES) suppresses thermal fluctuations in the TES and well-thermally coupled regions in proximity. We have designed a heavily metallized, leg-isolated membrane with a TES which serves as a thermal isolation stage that can be lithographically integrated with other devices, for example, a suitably designed TES detector. Through modeling, fabrication, and test of prototype devices, we plan to examine the utility of stabilizing this guard stage to limit low frequency variability in the sensor response. In one implementation, a leg-isolated TES bolometer of higher superconducting transition temperature ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T_c</i> ) is encircled by a second membrane region which is metallized and thermally stabilized by a second, lower- <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T_c</i> TES. We present fabrication results on the dual- <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T_c</i> device and explore varied heat capacity of the thermal stability stage in the single-pixel design. We then evaluate the use of this stage for multiple pixel arrangements and investigate the criteria for stabilizing such a device.

Faster growth and larger size at crèche onset are associated with higher offspring survival in Adélie Penguins

Abstract We conducted the first assessment of Adélie Penguin (Pygoscelis adeliae) chick survival that accounts for imperfect resighting. We found that when chicks are larger in size when they enter the crèche stage (the period when both parents forage at the same time and chicks are left relatively unprotected), they have a higher probability of survival to fledging. We investigated the relationships between growth, crèche timing, and chick survival during one typical year and one year of reduced food availability. Chicks that hatched earlier in the season entered the crèche stage older, and chicks that both grew faster and crèched older entered the crèche at a larger size. These relationships were stronger in the year of reduced food availability. Thus, parents increased their chicks’ chance of fledging if they provided sufficient food for faster growth rates and/or extended the length of the brood-guarding period. Early nest initiation (i.e., early hatching) provided parents with the opportunity to extend the guard period and increase chick survival. However, to extend the guard stage successfully, they must provide larger meals and maintain higher chick growth rates, even if just one parent at a time is foraging, which previous work has shown is not possible for all individuals. We show that the factors governing tradeoffs in chick-rearing behavior of Adélie Penguin parents may vary in accord with environmental conditions, a result from which we can better understand species’ adaptations to environmental changes.

Etika Guru Perspektif Ibnu Saḥnūn Dalam Kitab Ādāb Al-Mu’allimīn

The purpose of this research was to determine teacher ethics in the perspective of Ibn Saḥnūn in the book Ādāb al-Mu'allimīn, to analyze teacher ethics in the book, and to analyze the implementation of the concept of teacher ethics according to him in Islamic education today. This research used Grounded Theory method, with a qualitative approach with the type of library research. Sources of data used primary and secondary data sources. Data collection was done by documentation. Analysis of the data used analysis of the content. The results showed that 1). teacher ethics according to Ibn Saḥnn in the Book of Ādāb al-Mu'allimīn there are 18 ethics, including: a). educate sincerely, b).mobilize all their abilities in educating students, c). staying away from differences in treatment of their students, d). be gentle with them, e). provide educational punishment, f). remind them not to play while studying, g). do not punish excessively, h). not burden them with financial problems, i). responsible, j). Prioritize important lessons, k). get them used to doing sunnah practices, l). Pay attention to the development of their manners and morals, m). give advice to them, n). be fair, o). keep themselves busy with writing and adding knowledge, p). Meet their personal needs, q). instilling students' love for Allah, r). maintain the sanctity and cleanliness of the study area. 2) The analysis of teacher ethics in the book is very religious because it is in accordance with the Qur'an and Sunnah, as well as the opinions of scholars, and contains the same elements as those formulated in the National Education Standards, Elucidation of Article 28 paragraph (3 ) point b, and is also in line with the Law on Teachers and Lecturers Chapter 3 Article 7 concerning the principle of teacher professionalism. 3). According to him, the implementation of the concept of teacher ethics in Islamic education today can be implemented in educational institutions in five stages, namely: a). preparation stage, b). planting stage, c). growth stage, d). development stage, and e). guard stage.

An exception handling framework for case management

In order to achieve their business goals, organizations heavily rely on the operational excellence of their business processes. In traditional scenarios, business processes are usually well-structured, clearly specifying when and how certain tasks have to be executed. Flexible and knowledge-intensive processes are gathering momentum, where a knowledge worker drives the execution of a process case and determines the exact process path at runtime. In the case of an exception, the knowledge worker decides on an appropriate handling. While there is initial work on exception handling in well-structured business processes, exceptions in case management have not been sufficiently researched. This paper proposes an exception handling framework for stage-oriented case management languages, namely Guard Stage Milestone Model, Case Management Model and Notation, and Fragment-based Case Management. The effectiveness of the framework is evaluated with two real-world use cases showing that it covers all relevant exceptions and proposed handling strategies.

Exploring the interplay between nest vocalizations and foraging behaviour in breeding birds

In many bird species, reproductive partners sing together each time they meet on the nest. Because these nest ceremonies typically correspond to the return of one partner from foraging and to the subsequent departure of the other partner, we hypothesized that the foraging decisions of departing birds may be facilitated by the vocalizations accompanying their partner's return on the nest, providing these vocalizations reflect foraging conditions. We examined this hypothesis in pairs of Adélie penguins, Pygoscelis adeliae , by longitudinally monitoring their nest vocalizations and their spatial distribution when foraging at sea across the guard stage, when both parents regularly alternate foraging at sea and chick attendance at the nest. We found that the acoustic characteristics of the vocalizations produced during nest relief ceremonies reflected some characteristics of the foraging trips of both the returning and departing partners. However, these acoustic characteristics differed between partners and were differently related to their foraging behaviour. Accordingly, departing individuals did not adopt the same foraging behaviour as that of returning individuals. Nest vocalizations therefore do not appear to represent cues facilitating the foraging decisions of departing birds, but they may rather reflect the arousal of partners, which differently correlates with the foraging behaviour of the returning and departing individuals. Our study highlights an interplay between the vocalizations produced on the nest by reproductive partners and their foraging behaviour, thereby broadening the scope of animal vocalizations and opening a novel perspective on the regulation of foraging strategies. However, our exploratory study also highlights the complexity of examining this interplay, as the effects of nest vocalizations on foraging decisions may be complicated by other factors (e.g. intrinsic foraging capacity). This calls for the use of additional and experimental approaches (e.g. vocalization playbacks) to clarify the role of nest vocalizations as potential mediators of foraging decisions. • Bird reproductive partners typically sing together each time they meet on the nest. • In Adélie penguins, nest vocalizations reflected some foraging characteristics. • These characteristics differed between partners leaving or returning to the nest. • Nest vocalizations presumably reflect the arousal of partners. • Additional approaches are needed to clarify this vocalization/foraging interplay.

What’s for dinner mom? Selective provisioning in southern rockhopper penguins (Eudyptes chrysocome)

Breeding seabirds must balance self-care and reproduction, especially once offspring have hatched and have to be fed regularly. Seabirds may selectively provision chicks with higher quality food than they consume themselves. In contrast, adults may prioritize their survival rather than their progeny by feeding chicks with lower quality prey items than they feed themselves. We examined the parental provisioning strategies of southern rockhopper penguins at Isla de los Estados in 2012 using nitrogen (δ15N) and carbon (δ13C) stable isotope analysis to determine if selective provisioning and foraging habitat differences exist between parents and their offspring. We found that chicks had higher δ15N values compared to both male and female penguins, and female had slightly higher δ15N values compared to male penguins. There was also a strong positive relationship in δ15N values between female penguins and their offspring, indicating that chicks’ diet resembles the female parent more than the male parent. Our results support the hypothesis of selective provisioning of chicks with higher trophic level (i.e., δ15N value) prey and the observation that females exclusively feed chicks during the guard stage. We did not find differences in δ13C values between adult and chicks suggesting no differences in the areas or habitats used to forage for self-provisioning and chick-provisioning. These findings likely have broader significance as provisioning rates and quality of food consumed by chicks is often strongly related to chick growth and survival.

Scale matters: sea ice and breeding success of Adélie penguins

Southern Ocean ecosystems are extremely vulnerable to sea-ice changes occurring at different spatial and temporal scales. Variability in the sea-ice conditions strongly influence the survival and reproduction of animals that are synchronized with the seasonality of sea ice. Although the linkages between Adelie penguins (Pygoscelis adeliae) and sea-ice conditions are well established, the spatial and temporal scales at which sea ice affects individuals and populations are poorly known. Using 23 years of penguin breeding success and remote-sensing data of sea ice, we investigate the spatial and temporal scales at which sea-ice changes best explain variations in the reproductive success of Adelie penguins at Pointe Geologie, East Antarctica. The best spatial scale encompassed all foraging areas exploited and all the sea-ice conditions encountered by penguins over a breeding season. There was a consistent influence of sea-ice concentration during the guard stage on the overall breeding success. We demonstrate the importance of considering sea ice at a fine temporal scale rather than using an average value over the breeding season to best explain reproductive success in Adelie penguins.

Variation in Corticosterone Levels in Two Species of Breeding Albatrosses with Divergent Life Histories: Responses to Body Condition and Drivers of Foraging Behavior.

Corticosterone (CORT) is a glucocorticoid hormone that maintains energy balance and can modulate foraging behaviors in seabirds. However, CORT responses are not always predictable under similar biophysical conditions and do not necessarily influence the same behaviors across breeding stages and species. To enhance our understanding of CORT's role as a proximate determinant of foraging behavior and energy maintenance, we examined the relationships between body condition, CORT, foraging behavior, and foraging success between two sympatric breeding albatross species with differing foraging strategies and life histories, the Campbell albatross (Thalassarache impavida) and the gray-headed albatross (Thalassarache chrysostoma), from Campbell Island, New Zealand. Pre- and postforaging CORT did not differ between species or stage, potentially as a result of behavioral plasticity or different functional roles of CORT across stages. Unexpectedly, body condition did not correlate with preforaging CORT during incubation, although a negative correlation was observed in Campbell albatrosses during the guard stage. Furthermore, CORT mediated foraging success in both species and stages, but CORT mediated foraging behavior only in incubation-stage Campbell albatrosses that had shorter foraging ranges with higher pretrip CORT. Additionally, CORT positively correlated with mass gain and the time elapsed since the last feeding event in guard-stage albatrosses. Our results highlight the complexity of CORT in mediating energy balance in free-ranging animals. Our results also support that if CORT is to be usefully interpreted, breeding stage must be considered because the physiological and behavioral functionality of CORT may differ across stages, with enhanced sensitivity to energy reserves during chick rearing.

Foraging plasticity of breeding Northern Rockhopper Penguins, Eudyptes moseleyi, in response to changing energy requirements

During the breeding season, seabirds must balance the changing demands of self- and off-spring provisioning with the constraints imposed by central-place foraging. Recently, it was shown that Northern Rockhopper Penguins at Tristan da Cunha in the South Atlantic Ocean switch diet from lower to higher trophic level prey throughout their breeding cycle. Here, we investigated if this switch is reflected in their foraging behaviour, using time-depth recorders to study the diving behaviour of 27 guard and 10 creche birds during the breeding season 2010 at Tristan da Cunha and obtaining complementary stomach contents of 20 birds. While no significant effects of breeding stage were detected on any foraging trip or dive parameters, stage/prey had a significant effect on feeding dive parameters, with dive duration, bottom time, and maximum depth explaining the majority of the dissimilarity amongst categories. We verified the previously shown dietary shift from zooplankton and cephalopods during the guard stage to a higher-energy fish-based diet during the creche stage, which was reflected in a change in dive behaviour from shorter, shallower to longer, deeper dives. This prey switching behaviour may reflect preferential selection to account for the increased physiological needs of chicks or simply mirror changes in local prey abundance. Nonetheless, we show that Northern Rockhopper Penguins demonstrate behavioural plasticity as a response to their changing energy requirements, which is a critical trait when living in a spatio-temporally heterogeneous environment. This ability is likely to be particularly important under extrinsic constraints such as long-term environmental change.

Variability in the Foraging Distribution and Diet of Cape Gannets between the Guard and Post-guard Phases of the Breeding Cycle

During breeding, seabirds are central place foragers and are sensitive to changes in local prey availability. As the breeding season progresses, the foraging behaviour and distribution is expected to change in response to possible changes in local prey availability. In addition adult gender, and the increasing nutritional demands of a growing chick may also influence the foraging behaviour of individuals. At present, few studies have assessed the foraging behaviour of adult birds during the late post-guard stages of chick rearing. Through a combination of GPS tracking and diet sampling we investigated the foraging distances, spatial distribution and prey composition of adult Cape gannets (Morus capensis) during the guard and post guard-stages of chick rearing. We found no clear evidence for consistent sex-specific differences in foraging behaviour and spatial distribution during the guard stage, although marginal differences in the location of core foraging areas during the post-guard stage were apparent. Results, however, revealed a clear increase in foraging range from the early guard to the late post-guard stage of chick rearing. During December the diet was comprised almost exclusively of anchovy (Engraulis encrasicolus), the proportion of which had decreased significantly in the diet by January. This was mirrored by a substantial increase in the proportion of saury (Scomberesox saurus). These results suggest that Cape gannets show flexibility in the foraging behaviour and diet, which may be related to changes in the abundance and distribution of prey or may reflect changes in the energetic requirements of the growing offspring. This study provides the first assessment of Cape gannet foraging behaviour and spatial distribution during the post-guard stage of chick rearing. The importance of considering intra-annual variability in foraging distribution when using seabird tracking data in trophic and marine spatial planning studies are highlighted.

Foraging behaviour of Magellanic Penguins during the early chick‐rearing period at Isla de los Estados, Argentina

Studies of the at‐sea distribution and trophic ecology of penguins are essential to understand their role in the broader marine food web. Magellanic Penguins Spheniscus magellanicus have a wide distribution and their foraging behaviour varies across breeding sites and between sexes, among others. In this study, we characterized the at‐sea areas, the diving strategies and the relative trophic level of Magellanic Penguins breeding at Isla de los Estados, Argentina, during the early chick‐rearing period. In addition, we quantified the interannual, sexual and individual variability in those parameters during three breeding seasons (2011–2013) using devices recording position and dive depth, and obtained blood samples for stable isotope analysis. During the early chick‐rearing period, Magellanic Penguins showed small differences between the sexes in their foraging behaviour and large overlap in the at‐sea areas used, suggesting no intraspecific variation between sexes. Although there was interannual variability in the foraging behaviour and the trophic level of the penguins, most of the studied nests managed successfully to raise both chicks during the first stage of the breeding cycle (guard stage). The foraging ecology of Magellanic Penguins from this colony was comparable with results of past studies at other breeding colonies. This study contributes to the identification of important at‐sea areas for Magellanic Penguins at the southern edge of their distribution and also to the identification of possible threats in the study area such as interaction with fisheries.

Departure time influences foraging associations in little penguins.

Recent studies have documented that little penguins (Eudyptula minor) associate at sea, displaying synchronised diving behaviour throughout a foraging trip. However, previous observations were limited to a single foraging trip where only a small number of individuals were simultaneously tracked. Consequently, it is not known whether coordinated behaviour is consistent over time, or what factors influence it. In the present study, breeding adults were concurrently instrumented with GPS and dive behaviour data loggers for at least 2 consecutive foraging trips during guard and post-guard stage at two breeding colonies (London Bridge and Gabo Island, south-eastern Australia) of contrasting population size (approximately 100 and 30,000–40,000, respectively). At both colonies, individuals were sampled in areas of comparable nesting density and spatial area. At London Bridge, where individuals use a short (23 m) common pathway from their nests to the shoreline, > 90% (n = 42) of birds displayed foraging associations and 53–60% (n = 20) maintained temporally consistent associations with the same conspecifics. Neither intrinsic (sex, size or body condition) nor extrinsic (nest proximity) factors were found to influence foraging associations. However, individuals that departed from the colony at a similar time were more likely to associate during a foraging trip. At Gabo Island, where individuals use a longer (116 m) pathway with numerous tributaries to reach the shoreline, few individuals (< 31%; n = 13) from neighbouring nests associated at sea and only 1% (n = 1) maintained associations over subsequent trips. However, data from animal-borne video cameras indicated individuals at this colony displayed foraging associations of similar group size to those at London Bridge. This study reveals that group foraging behaviour occurs at multiple colonies and the pathways these individuals traverse with conspecifics may facilitate opportunistic group formation and resulting in foraging associations irrespective of nesting proximity and other factors.

Prey-field use by a Southern Ocean top predator: enhanced understanding using integrated datasets

An important challenge for understanding and managing marine ecosystems is determining the relationship between the distributions of prey species and the foraging of top predators. We examined the diet and foraging dynamics of breeding macaroni penguins Eudyptes chrysolophus from sub-Antarctic Heard Island and related these to prey distributions derived from active-acoustics and net-derived data in the foraging zone of the penguins. Consistent with previous findings, we found that penguin diets changed between the guard and creche stages of the breeding cycle and that this change in diet corresponded with a switch from short foraging trips in the guard stage to significantly longer, offshore foraging trips in the creche stage. We related these differences in diet and foraging to characteristics of the prey field—specifically, a relatively uniform distribution of krill over the shelf and in deeper, offshore waters, compared with an increasing abundance of fish further from shore. We developed a simple dynamic energy budget for macaroni penguins to explore whether targeting fish during the creche stage was an energetically favourable strategy. Finally, we extrapolated our energy budget to estimate prey consumption at the colony scale as previous work has suggested that depletion near breeding colonies could contribute to prey switching. We found that prey switching during the creche stage was energetically favourable and was most likely related to a reduction in foraging constraints, rather than prey depletion. This study shows the value of integrating data sets to address questions surrounding variation in diet and the use of alternative prey by marine predators.

Fine-scale spatial age segregation in the limited foraging area of an inshore seabird species, the little penguin

Competition for food resources can result in spatial and dietary segregation among individuals from the same species. Few studies have looked at such segregations with the combined effect of sex and age in species with short foraging ranges. In this study we examined the 3D spatial use of the environment in a species with a limited foraging area. We equipped 26 little penguins (Eudyptula minor) of known age, sex, and breeding output with GPS (location) and accelerometer (body acceleration and dive depth) loggers. We obtained dietary niche information from the isotopic analysis of blood tissue. We controlled for confounding factors of foraging trip length and food availability by sampling adults at guard stage when parents usually make one-day trips. We observed a spatial segregation between old (>11 years old) and middle-aged penguins (between 5 and 11 years old) in the foraging area. Old penguins foraged closer to the shore, in shallower water. Despite observing age-specific spatial segregation, we found no differences in the diving effort and foraging efficiency between age classes and sexes. Birds appeared to target similar prey types, but showed age-specific variation in their isotopic niche width. We hypothesize that this age-specific segregation was primarily determined by a "cohort effect" that would lead individuals sharing a common life history (i.e. having fledged and dispersed around the same age) to forage preferentially together or to share similar foraging limitations.

Northern rockhopper penguins prioritise future reproduction over chick provisioning

As iteroparous species, seabirds must balance present against future reproduction. We used stable-isotope (SIA) and stomach content analysis (SCA) to examine the effects of sex, breeding stage, pre-moulting period, ontogeny and chick age on the diet of northern rockhopper penguins (NRP; Eudyptes moseleyi) breeding at the Tristan da Cunha archipelago during 2010. Stomach contents were obtained from birds during the guard and creche stages. δ 15 N and δ 13 C signatures of whole blood of adults were measured at Tristan Island (during the incubation, guard and creche stages), and of adult feathers at Tristan and nearby (-38 km) Nightingale Islands. δ 15 N and δ 13 C signatures of the whole blood of chicks were also measured during both stages. Adult pre-moult diets were significantly enriched in both elements at Nightingale compared to Tristan Islands. Adult female diet was dominated by zooplankton during the guard stage, and in both sexes by fish (predominantly Photichthyidae) in the creche stage. No effects of chick size within the guard stage, or of sex within the creche stage were observed on diet composition of adult birds. δ 13 C values of adult blood were higher in females relative to chicks, and in creche relative to guard stage individuals. δ 15 N values of blood showed a significant breeding stage x chick age interaction. Sex affected blood δ 15 N and δ 13 C only in the guard and incubation stages. Stage and sex interacted significantly on δ 13 C and δ 15 N signatures of adult feathers. NRP were opportunistic foragers, hunting in different areas during breeding and non-breeding periods, with different pre-moult foraging patterns observed in adults from colonies separated by only 38 km. Adults seemed to favour future reproduction, through brood reduction and by feeding chicks lower trophic level prey than they consumed themselves, although provisioning shifted from zooplankton to fish later in the breeding season.

Elevated corticosterone levels decrease reproductive output of chick-rearing Adelie penguins but do not affect chick mass at fledging

Study of physiological mechanisms can help us to understand how animals respond to changing environmental conditions. In particular, stress hormones (i.e. glucocorticoids, such as corticosterone) are described as mediating resource allocation, allowing animals to adjust their physiology and behaviour to predictable and unpredictable changes in the environment. In this study, we investigated the effects of an experimental increase in baseline corticosterone levels on the breeding effort and the reproductive output of chick-rearing male Adélie penguins (Pygoscelis adeliae). The number of chicks per nest, their body mass, and their size were monitored throughout the study. Direct observations allowed measurement of the time spent foraging at sea and caring for the young on the nest. At the end of the treatment, blood samples were collected for isotope analysis. Although all birds raised at least one chick, reproductive output was decreased by 42% in corticosterone-treated birds compared with control birds. The increase in corticosterone levels during the guard stage did not affect the mass of surviving chicks or the brood mass at fledging. Corticosterone-treated males spent on average 21% more time at the nest than control birds. However, the duration of foraging trips was similar between both groups. In addition, the similarity of isotopic signatures suggests that both groups foraged at similar locations and ingested the same prey species. The detailed on-land behaviour of birds should be examined in further studies to clarify the possible links between corticosterone levels, brooding time, and reproductive output. Understanding the relationships between glucocorticoids, fitness, and ultimately population dynamics is fundamental to enabling conservation physiology as a discipline to be successful in helping to manage species of conservation concern.

Better late than never? Interannual and seasonal variability in breeding chronology of gentoo penguins at Stranger Point, Antarctica

Rapid climate change recorded in the western Antarctic Peninsula confronts species with less predictable conditions in the marine and terrestrial environments. We analysed the breeding chronology and nesting site selection of gentoo penguins (Pygoscelis papua) at King George Island (Isla 25 de Mayo), Antarctica, during four seasons in which differences in snow presence and persistence on the ground were observed. We recorded an overall delay as well as seasonal asynchrony at the beginning of reproduction for those years with higher snow deposition. A redistribution of breeding groups was also observed. Nevertheless, the population breeding success and chicks’ weight at fledging remained relatively constant, despite the delay in breeding chronology, the increased duration of foraging trips during the guard stage and the decreased weight of stomach contents during the crèche stage. We suggest that the plasticity of their trophic biology, along with the flexibility of their breeding phenology and relocation of breeding groups, may be complementary reasons why gentoo penguin populations in the region have remained stable in spite of the changing conditions currently registered.Keywords: Antarctica; breeding delay; breeding phenology; snow; Pygoscelis papua; Euphausia superba (Published: 13 May 2013)Citation: Polar Research 2013, 32, 18448, http://dx.doi.org/10.3402/polar.v32i0.18448

Sexual segregation in rockhopper penguins during incubation

Many animals show sex differences in foraging behaviour, which can be related to sex-specific size dimorphism, avoidance of intersexual competition for depletable resources or different energetic requirements of males and females. In southern rockhopper penguins, Eudyptes chrysocome , both sexes differ in their roles during breeding, which leads to differences in their energetic requirements. We therefore examined sex differences in the foraging behaviour of southern rockhopper penguins during the incubation period, using GPS and time–depth data, stable isotope analysis and an automated weighbridge system. While males carried out mostly long trips lasting several days, females often used coastal foraging areas on day trips. Stable isotope data suggested differences in prey composition between the sexes, with consistently higher trophic levels in males as expected for their larger size and ability to catch larger prey items. We applied ecological niche models to compare the environmental conditions in the utilized incubation season habitat between the sexes, using MaxEnt modelling. MaxEnt models suggested that the niche spaces of males and females are largely overlapping, but males have slightly larger niche width. The most important environmental parameter was sea surface temperature. The different energetic requirements related to the birds' incubation and chick-provisioning pattern seem to be the driving force behind the observed spatial segregation. Males make use of highly productive areas to prepare for subsequent fasting periods whereas females forage in coastal waters for themselves as well as for the chicks during the subsequent guard stage. ► Male and female rockhopper penguins use different foraging areas during incubation. ► Male rockhopper penguins feed on higher trophic levels compared to females. ► Male and female rockhopper penguins overlap in their niche space. ► Energetic requirements are the driving force in spatial segregation between sexes.

Evaluating the Impact of Handling and Logger Attachment on Foraging Parameters and Physiology in Southern Rockhopper Penguins

Logger technology has revolutionised our knowledge of the behaviour and physiology of free-living animals but handling and logger attachments may have negative effects on the behaviour of the animals and their welfare. We studied southern rockhopper penguin (Eudyptes chrysocome) females during the guard stage in three consecutive breeding seasons (2008/09−2010/11) to evaluate the effects of handling and logger attachment on foraging trip duration, dive behaviour and physiological parameters. Smaller dive loggers (TDRs) were used in 2010/11 for comparison to larger GPS data loggers used in all three seasons and we included two categories of control birds: handled controls and PIT control birds that were previously marked with passive integrative transponders (PITs), but which had not been handled during this study. Increased foraging trip duration was only observed in GPS birds during 2010/11, the breeding season in which we also found GPS birds foraging further away from the colony and travelling longer distances. Compared to previous breeding seasons, 2010/11 may have been a period with less favourable environmental conditions, which would enhance the impact of logger attachments. A comparison between GPS and TDR birds showed a significant difference in dive depth frequencies with birds carrying larger GPS data loggers diving shallower. Mean and maximum dive depths were similar between GPS and TDR birds. We measured little impact of logger attachments on physiological parameters (corticosterone, protein, triglyceride levels and leucocyte counts). Overall, handling and short-term logger attachments (1–3 days) showed limited impact on the behaviour and physiology of the birds but care must be taken with the size of data loggers on diving seabirds. Increased drag may alter their diving behaviour substantially, thus constraining them in their ability to catch prey. Results obtained in this study indicate that data recorded may also not represent their normal dive behaviour.

On the equivalence of incremental and fixpoint semantics for business artifacts with Guard–Stage–Milestone lifecycles

Business artifacts (or simply, artifacts) are used to model conceptual entities that are central to guiding the operations of a business, and whose content changes as they move through those operations. The recently introduced Guard–Stage–Milestone (GSM) meta-model for artifact lifecycles is declarative in nature, and allows concurrent execution of long-running (possibly human-executed) activities. Modularity is incorporated through the use of hierarchical clustering of activities. Milestones are used to track whether key business-relevant operational objectives have been achieved by a business artifact. The GSM operational semantics is based on a variant of Event-Condition-Action (ECA) rules, which are used to control the start and termination of individual and composite activities, and the recording of milestone status. This paper introduces, in an abstract setting, three different and provably equivalent formulations of the GSM operational semantics. The semantics is specified in terms of how a single external event is incorporated into the current “snapshot” (i.e., full description) of a running execution of an artifact model. The “incremental” formulation corresponds to the sequential application of the ECA-like rules in response to the event; the “fixpoint” formulation characterizes the mathematical properties of pairs of snapshots corresponding to the full impact of incorporating the event; and the “closed-form” formulation captures the fixpoint one in terms of first-order logic. The paper introduces a formally specified well-formedness condition on GSM models that guarantees the equivalence of the three formulations while permitting commonly arising patterns for using GSM constructs to model business operations.