Changes in behaviour during the inter-nesting period and post-nesting migration for Ascension Island green turtles

Satellite transmitters were attached to green turtles Chelonia mydas while they were nesting on Ascension Island in the South Atlantic (7°57'S, 14°22'W) and individuals were subsequently monitored during the inter-nesting period and the post-nesting migration to Brazil. During the inter-nesting period, data from the transmitters suggested that turtles generally stayed within 5 km of the nesting beach on which they had originally been observed. During both the inter-nesting period and migration, turtles were submerged the vast majority (>95%) of the time, suggesting that they neither basked at the surface nor drifted passively during migration to any great extent. There was a clear dichotomy in submergence behaviour, with submergences tending to be of short duration during post-nesting migration (mean = 7.3 min, 3318 h of data from 5 individuals) and of longer duration during the inter-nesting period (mean = 22.1 min, 714 h of data from 5 different individuals). As submergence duration is generally linked to activity levels in sea turtles, this pattern suggests that turtles were comparatively inactive during the inter-nesting period and comparatively active during migration. During both the inter-nesting period and the post-nesting migration, diel submergence patterns were detected with dive duration tending to be longer at night. As the turtles migrated WSW from Ascension Island, there was a reduction in their speed of travel. A numerical model of the near-surface currents suggested that this reduction was associated with the weakening of the WSW flow of the prevailing South Atlantic Equatorial Current.

Distribution Entropy (DistEn) : a complexity measure to detect arrhythmia from short length RR interval time series

Heart rate complexity analysis is a powerful non-invasive means to diagnose several cardiac ailments. Non-linear tools of complexity measurement are indispensable in order to bring out the complete non-linear behavior of Physiological signals. The most popularly used non-linear tools to measure signal complexity are the entropy measures like Approximate entropy (ApEn) and Sample entropy (SampEn). But, these methods become unreliable and inaccurate at times, in particular, for short length data. Recently, a novel method of complexity measurement called Distribution Entropy (DistEn) was introduced, which showed reliable performance to capture complexity of both short term synthetic and short term physiologic data. This study aims to i) examine the competence of DistEn in discriminating Arrhythmia from Normal sinus rhythm (NSR) subjects, using RR interval time series data; ii) explore the level of consistency of DistEn with data length N; and iii) compare the performance of DistEn with ApEn and SampEn. Sixty six RR interval time series data belonging to two groups of cardiac conditions namely `Arrhythmia' and `NSR' have been used for the analysis. The data length N was varied from 50 to 1000 beats with embedding dimension m = 2 for all entropy measurements. Maximum ROC area obtained using ApEn, SampEn and DistEn were 0.83, 0.86 and 0.94 for data length 1000, 1000 and 500 beats respectively. The results show that DistEn undoubtedly exhibits a consistently high performance as a classification feature in comparison with ApEn and SampEn. Therefore, DistEn shows a promising behavior as bio marker for detecting Arrhythmia from short length RR interval data.

Cost optimal resource provisioning for live video forwarding across video data centers

Live video forwarding for IP cameras has become a popular service in video data centers. In the forwarding service, requests of end users from different regions arrive in real-time to gain live video streams of IP cameras from inter-connected video data centers. A fundamental scheduling problem is how to assign resources with the global optimal resource cost and forwarding delay to forward live video streams. We introduce the resource provisioning cost as the combination of media server cost, connection bandwidth cost, and forwarding delay cost. In this paper, a multi-objective resource provisioning (MORP) approach is proposed to deal with the online inter-datacenter resource provisioning problem. The approach aims at minimizing the resource provisioning cost during live video forwarding. It adaptively allocates media servers in appropriate video data centers and connects the chosen media servers together to provide system scalability and connectivity. Different from previous works, MORP takes both resource capacity and diversity (e.g. location and price) into consideration during live video forwarding. Finally, the experimental results show that MORP approach not only cuts the resource provisioning cost of 3% to 10% comparing to the bench mark approach, but also shortens the resource provisioning delay.

From neuroprogression to neuroprotection : implications for clinical care

• Bipolar disorder follows a staged trajectory in which persistence of illness is associated with a number of clinical features such as progressive shortening of the inter-episode interval and decreased probability of treatment response.

• This neuroprogressive clinical process is reflected by both progressive neuroanatomical changes and evidence of cognitive decline.

• The biochemical foundation of this process appears to incorporate changes in inflammatory cytokines, cortisone, neurotrophins and oxidative stress. There is a growing body of evidence to suggest that these markers may differ between the early and late stages of the disorder.

• The presence of a series of tangible targets raises the spectre of development of rational neuroprotective strategies, involving judicious use of current therapies and novel agents. Most of the currently used mood stabilisers share effects on oxidative stress and neurotrophins, while novel potentially neuroprotective agents are being developed. These developments need to be combined with service initiatives to maximise the opportunities for early diagnosis and intervention.

On extending generalized Bonferroni means to Atanassov orthopairs in decision making contexts

Extensions of aggregation functions to Atanassov orthopairs (often referred to as intuitionistic fuzzy sets or AIFS) usually involve replacing the standard arithmetic operations with those defined for the membership and non-membership orthopairs. One problem with such constructions is that the usual choice of operations has led to formulas which do not generalize the aggregation of ordinary fuzzy sets (where the membership and non-membership values add to 1). Previous extensions of the weighted arithmetic mean and ordered weighted averaging operator also have the absorbent element 〈1,0〉, which becomes particularly problematic in the case of the Bonferroni mean, whose generalizations are useful for modeling mandatory requirements. As well as considering the consistency and interpretability of the operations used for their construction, we hold that it is also important for aggregation functions over higher order fuzzy sets to exhibit analogous behavior to their standard definitions. After highlighting the main drawbacks of existing Bonferroni means defined for Atanassov orthopairs and interval data, we present two alternative methods for extending the generalized Bonferroni mean. Both lead to functions with properties more consistent with the original Bonferroni mean, and which coincide in the case of ordinary fuzzy values.

Clutch size for Mediterranean loggerhead turtles (Caretta caretta)

We investigated the number of eggs laid and the total clutch volume for loggerhead turtles (Caretta caretta L.) nesting on the Greek island of Cephalonia (38° 09′ N, 20° 33′ E) during 1990. Both the number of eggs laid and clutch volume were positively related to female body size, and the mean explained variation for these relationships (36·6% and 37·7%, respectively) were not significantly different. Clutch volume decreased as the season progressed because individuals laid successively smaller clutches. The inter-nesting interval (range 15–19 days) did not significantly influence the number of eggs laid or clutch volume. For individuals seen laying more than once, female size in combination with the number of a clutch in relation to all the clutches observed for that individual, together explained 65·5% of the variation in clutch volume.

Poor tolerance of motor cortex rTMS in chronic migraine

Background:
Two small studies had evaluated the efficacy of rTMS in migraine. One tested high frequency rTMS over the dorsolateral prefrontal cortex while the other evaluated 1 Hz rTMS over the vertex.
Aim:
To test the feasibility of 10 Hz rTMS of motor cortex as an adjunctive therapy in patients with chronic migraine.
Materials and Methods:
We randomized (2:1 ratio) chronic migraine patients on medical preventive treatment to receive either rTMS or sham therapy for 10 sessions. rTMS (80% resting motor threshold, 10Hz, 20 trains, 5 secs/train, inter-train interval 1 min, total 1000 stimuli/session) was applied over the right motor cortex.
Result:
Nine patients were randomized. Six received rTMS
and three had sham therapy. Three patients in the rTMS arm withdrew from the study due to increased headache frequency and discomfort from the treatment. The remaining six cases (3 rTMS, 3 sham) completed the study. The study was prematurely stopped due to the significant worsening of headache from rTMS. No significant differences in outcome measures were found between real and sham rTMS.
Conclusion:
Although the study was terminated prematurely, the high dropout rate (50%) due to worsening headaches suggested that rTMS over the motor cortex is poorly tolerated in chronic migraine.

Noisy neighbours at the frog pond: effects of invasive cane toads on the calling behaviour of native Australian frogs

Invasive species can disrupt the communication systems that native biota use for reproductive interactions. In tropical Australia, invasive cane toads (Rhinella marina) breed in many of the same waterbodies that are used by native frogs, and males of both the invader and the native taxa rely on vocal signals to attract mates. We conducted playback experiments to test the hypothesis that calls of toads may influence the calling behaviour of frogs (Limnodynastes convexiusculus and Litoria rothii). Male L. convexiusculus adjusted their calling rate and the variance in inter-call interval in response to a variety of sounds, including the calls of cane toads as well as those of other native frog species, and other anthropogenic noise, whereas L. rothii did not. Within the stimulus periods of playbacks, male L. convexiusculus called more intensely during long silent gaps than during calling blocks. Thus, males of one frog species reduced their calling rate, possibly to minimise energy expenditure during periods of acoustic interference generated by cane toads. In spite of such modifications, the number of overlapping calls (within stimulus periods) did not differ significantly from that expected by chance. In natural conditions, the calls of cane toads are continuous rather than episodic, leaving fewer gaps of silence that male frogs could exploit. Future work could usefully quantify the magnitude of temporal (e.g. diel and seasonal) and spatial overlap between calling by toads and by frogs and the impact of call-structure shifts on the ability of male frogs to attract receptive females.

Tough decisions: Reproductive timing and output vary with individuals' physiology, behavior and past success in a social opportunistic breeder

This article is part of a Special Issue SBN 2014. Photoperiod and the hormonal response it triggers are key determinants of reproductive timing in birds. However, other cues and physiological traits may permit flexibility in the timing of breeding and perhaps facilitate adaptation to global change. Opportunistic breeders are excellent models to study the adaptive significance of this flexibility, especially at the individual level. Here, we sought to quantify whether particular male physiological and behavioral traits were linked to reproductive timing and output in wild-derived zebra finches. We repeatedly assessed male stress-induced corticosterone levels (CORT), basal metabolic rate (BMR), and activity before releasing them into outdoor aviaries and quantifying each pair's breeding timing, investment, and output over a seven-month period. Despite unlimited access to food and water, the colony breeding activity occurred in waves, probably due to interpair social stimulations. Pairs adjusted their inter-clutch interval and clutch size to social and temperature cues, respectively, but only after successful breeding attempts, suggesting a facultative response to external cues. When these effects were controlled for statistically or experimentally, breeding intervals were repeatable within individuals across reproductive attempts. In addition, males' first laying date and total offspring production varied with complex interactions between pre-breeding CORT, BMR and activity levels. These results suggest that no one trait is under selection but that, instead, correlational selection acts on hormone levels, metabolism, and behavior. Together our results suggest that studying inter-individual variation in breeding strategy and their multiple physiological and behavioral underpinnings may greatly improve our understanding of the mechanisms underlying the evolution of breeding decisions.

Multi-lag HRV analysis discriminates disease progression of post-infarct people with no diabetes versus diabetes

Diabetes mellitus is associated with multi-organ system dysfunction including the cardiovascular and autonomic nervous system. Although it is well documented that post-infarct patients are at higher risk of sudden cardiac death, diabetes adds an additional risk associated with autonomic neuropathy. However it is not known how the presence of diabetes in post-infarct patients affects cardiac rhythm. The majority of HRV algorithms for determining cardiac inter-beat interval changes describe only beat-to-beat variation determined over the whole heart rate recording and therefore do not consider the ability of a heart beat to influence a train of succeeding beats nor whether or how the temporal dynamics of the inter-beat intervals changes. This study used Poincaré Plot derived features and incorporated increased lag intervals to compare post-infarct patients with no history of prior infarct with or without diabetes and found that for the nondiabetic post-infarct patients only increased lag of short term correlation (SD1) predicted mortality, whereas in the diabetic post-infarct group only long-term correlations (SD2) significantly predicted mortality at a follow-up period of eight years. Temporal dynamics measured as a complex correlation measure (CCM) was also a significant predictor of mortality only in the diabetic post-infarct cohort. This study highlights the different pathophysiological progression and risk profile associated with presence of diabetes in a post-infarct patient population at eight year follow-up.

Prediction interval-based neural network modelling of polystyrene polymerization reactor - a new perspective of data-based modelling

In this paper, prediction interval (PI)-based modelling techniques are introduced and applied to capture the nonlinear dynamics of a polystyrene batch reactor system. Traditional NN models are developed using experimental datasets with and without disturbances. Simulation results indicate that traditional NNs cannot properly handle disturbances in reactor data and demonstrate a poor forecasting performance, with an average MAPE of 22% in the presence of disturbances. The lower upper bound estimation (LUBE) method is applied for the construction of PIs to quantify uncertainties associated with forecasts. The simulated annealing optimization technique is employed to adjust NN parameters for minimization of an innovative PI-based cost function. The simulation results reveal that the LUBE method generates quality PIs without requiring prohibitive computations. As both calibration and sharpness of PIs are practically and theoretically satisfactory, the constructed PIs can be used as part of the decision-making and control process of polymerization reactors. © 2014 The Institution of Chemical Engineers.