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Compact power splitters are essential components in integrated optics. While 1 × 2 power splitters with uniform splitting are widely used, a 1 × N splitter with arbitrary number N of ports and arbitrary splitting ratio is yet to be demonstrated. In this work we address this problem. We fabricate and characterise 1 × N integrated power splitters that provide fully arbitrary splitting ratios. The core of our design is represented by an array of N non-equally spaced waveguides fabricated on a silicon nitride-on-insulator wafer. Any arbitrary 1 × N splitting ratio can be achieved by properly setting the array length and the dimension of the (N–1) nano-gaps between the adjacent waveguides. Most importantly, at variance with state-of-the-art solutions, our devices can be designed for arbitrary splitting of higher-order modes. In this manuscript we provide the first experimental demonstration of 1 × N arbitrary splitting ratio for both the fundamental modes (TE00 and TM00) and the TE01 mode, here up to N = 5 ports. With a footprint of 20 μm2/port, a bandwidth up to 70 nm and an excess losses

In recent years, it has been argued that the effect of predator fear exacts a greater demographic toll on prey populations than the direct killing of prey. However, efforts to quantify the effects of fear have primarily relied on experiments that replace predators with predator cues. Interpretation of these experiments must consider two important caveats: (1) the magnitude of experimenter-induced predator cues may not be realistically comparable to those of the prey's natural sensory environment, and (2) given functional predators are removed from the treatments, the fear effect is measured in the absence of any consumptive effects, a situation which never occurs in nature. We contend that demographic consequences of fear in natural populations may have been overestimated because the intensity of predator cues applied by experimenters in the majority of studies has been unnaturally high, in some instances rarely occurring in nature without consumption. Furthermore, the removal of consumption from the treatments creates the potential situation that individual prey in poor condition (those most likely to contribute strongly to the observed fear effects via starvation or reduced reproductive output) may have been consumed by predators in nature prior to the expression of fear effects, thus confounding consumptive and fear effects. Here, we describe an alternative treatment design that does not utilize predator cues, and in so doing, better quantifies the demographic effect of fear on wild populations. This treatment substitutes the traditional cue experiment where consumptive effects are eliminated and fear is simulated with a design where fear is removed and consumptive effects are simulated through the experimental removal of prey. Comparison to a natural population would give a more robust estimate of the effect of fear in the presence of consumption on the demographic variable of interest. This approach represents a critical advance in quantifying the mechanistic pathways through which predation structures ecological communities. Discussing the merits of both treatments will motivate researchers to go beyond simply describing the existence of fear effects and focus on testing their true magnitude in wild populations and natural communities., (© 2018 by the Ecological Society of America.)

The age trajectory of reproductive performance of many iteroparous species features an early - life increase in performance followed by a late - life senescent decline. The largest contribution of lifetime reproductive success is therefore gained at the age at which reproductive performance peaks. Using long term data on North American red squirrels we show that the environmental conditions individuals encountered could cause variation among individuals in the "height" and timing of this peak, contributing to life history variation and fitness in this population that experiences irregular resource pulses. As expected, high peak effort was positively associated with lifetime reproductive output up to a high level of annual effort. Furthermore, individuals that matched their peak reproductive effort to an anticipated resource pulse gained substantial fitness benefits through recruiting more offspring over their lifetime. Individual variation in peak reproductive effort thus has strong potential to shape life history evolution by facilitating adaptation to fluctuating environments.

In many species, females display brightly coloured and elaborate traits similar to those that males use in intra- and inter-sexual selection processes. These female characters are sometimes related to fitness, and might function as secondary sexual characteristics that have evolved through sexual selection. Here, we used descriptive data from 674 females in 10 populations and an experimental removal of Trichostrongylus tenuis parasites in four populations, to examine the effects of season, age, condition, and parasites on the size of supra-orbital combs displayed by female red grouse Lagopus lagopus scoticus. We found that comb size (i) was greater during the breeding than the non-breeding season, (ii) was greater in adult than in young females, (iii) was positively correlated with body condition, and (iv) negatively correlated with parasite abundance. Experimentally, we showed that comb size increased proportionally to the number of worms removed after parasite dosing. Our findings provide a better understanding of proximate mechanisms behind the expression of a male-like trait in females, and we discuss its possible function as a female ornament.

Background: A standardized and generally applicable scheme for grading the severity of poisoning allows a qualitative evaluation of morbidity and facilitates comparability of data. Working from a simple grading scale proposed by the European Association of Poisons Centres and Clinical Toxicologists, a Poisoning Severity Score has been developed jointly with the International Programme on Chemical Safety and the European Commission., Methods: The Poisoning Severity Score has been elaborated, tested, and gradually revised during a project running 1991-1994. Fourteen poisons centers from various countries have participated. Each center independently graded 371 cases of acute poisoning by ten different toxic agents. The data were then analyzed and compared., Results: The concordance in grading the severity increased during the study period, and in the last phase there was an acceptable concordance among centers in 80% or more of the cases. Given the condition and quality of the original case records, this result was considered satisfactory and agreement was reached on the scoring scheme presented here. The Poisoning Severity Score grades severity as (0) none, (1) minor, (2) moderate, (3) severe, and (4) fatal poisoning. It is intended to be an overall evaluation of the case, taking into account the most severe clinical features. Use of the Poisoning Severity Score normally requires a follow-up of all cases, but may be used on admission or other times during the course of poisoning if this is clearly stated when data are presented., Conclusions: A Poisoning Severity Score has been developed and found applicable for grading the severity of poisoning. It is foreseen that the Poisoning Severity Score will meet the expectations and be used in practice, but its future use and evaluation may result in some further revision and refinement.

Important developments concerning the role of antidotes in managing poisoning cases have taken place in recent decades due to new toxicodynamic and toxicokinetic studies and to growing international concern regarding the effectiveness of antidotes. A number of activities are carried out by the International Programme on Chemical Safety which aim to: (1) evaluate their effectiveness in clinical practice, (2) disseminate evaluated information, and (3) promote the availability of useful antidotes. The International Programme on Chemical Safety has undertaken the preparation of Antidote Monographs that summarize and assess the clinical use, mode of action, effectiveness, and other evaluated information, and a consolidated International Programme on Chemical Safety List of Antidotes that classifies antidotes and related drugs by their clinical effectiveness and urgency of need. A chart of Antidote Dosages, with information concerning the recommended antidotes and their indications, is being prepared, and the Availability of Antidotes in different countries is being surveyed. Further International Programme on Chemical Safety initiatives are also being undertaken in the area of antidotes and clinical toxicology in order to examine particular issues. The International Programme on Chemical Safety INTOX Project and related activities provide powerful tools for multicenter studies, but such research faces continuing financial and regulatory difficulties. Twinning arrangements between scientists from different parts of the world are being promoted to enhance the capabilities of evaluating treatment procedures and to compare clinical data. International organizations have important aims: to promote adequate and appropriate regulations and increase antidote availability, to establish international consensus and to increase interest in co-operative research. Cooperation with scientific bodies is essential in supporting these aims.

Antidotes may play an important role in the treatment of poisoning. For many physicians and toxicologists an antidote is an antidote. According to the IPCS definition, an antidote is a therapeutic substance used to counteract the toxic action(s) of a specified xenobiotic. Given this wide definition, the efficacy of an antidote may vary considerably depending on which toxic action(s) is/are being counteracted and on the level of counteracting power: An almost 100% efficacy is seen using specific antagonists, such as naloxone in opiate poisoning or flumazenil in benzodiazepine poisoning, e.g. resulting in complete reversal of opiate toxicity unless complications, such as anoxic brain damage, have developed. At the other end of the efficacy scale, we may place chelating agents for heavy metal poisoning and diazepam for organophosphorus insecticide poisoning. Therefore, in the IPCS/EC evaluation series of antidotes, some chelating agents are considered only to be an adjunct to supportive care which is the cornerstone of treatment. When teaching clinical toxicology or recommending the use of antidotes in poisoned patients, the expected efficacy level of the antidote in question should be stressed. This may be particularly important in severe poisonings when the antidote may only be considered as an adjunct to supportive care, e.g. deferoxamine in acute iron poisoning. Unless this is stressed, the unexperienced physician may rely too much on the antidote and may not pay sufficient attention to the supportive care. In this presentation, the varying efficacy levels of antidotes are discussed as based on the presently ongoing IPCS/EC evaluation programme on antidotes.