Life cycle assessment of Libyan crude oil

Petroleum products such as petrol and diesel are fossil fuels and have a high environmental impact. There is a demand to minimize these impacts especially in the upstream and midstream oil operations, i.e. exploration, production and refining processes, due to current and upcoming environmental regulations/policies and increased environmental consumer awareness. Thus, integration of the tools, methods and techniques for sustainability into products is becoming essential to comply with environmental regulations. The Libyan petroleum industry appears to be very slow in approaching modern concepts of approaches of sustainability including Life Cycle Assessment and studies. Therefore, this paper presents a novel environmental Life Cycle assessment of Libyan petroleum refining processes conducted with the support of Life Cycle Assessment methods and related tools including Software SimaPro. The refining processes from the Azzawya Oil refinery, are analyzed and used in the assessment and the data for the assessments was collected through fieldwork conducted in Feb 2013 in both El-Sharara oil field (Repsol Oil Company) and Azzawya Oil refinery in Libya. The results show that the first significant environmental impacts are associated with fossil fuels and the second major impacts are the respiratory inorganic impacts

Foraging mode switching : the importance of prey distribution and foraging currency

A.D.H. was supported by the European Research Council (Advanced Grant 250209 to Alasdair Houston), a College for Life Sciences Fellowship at the Wissenschaftskolleg zu Berlin, and a NERC Independent Research FellowshipNE/L011921/1.Foraging methods are highly variable, but can be grouped into two modes: searching and ambush. While research has focused on the functioning of each mode, the question of how animals choose which to use has been largely neglected. Here we consider a forager that exploits prey that are patchily distributed in space and time. This forager can either sit and wait for prey to appear or search for prey, which is more likely to result in encounters with prey but costs more energy and/or exposes the forager to greater predation risk. The currency that natural selection appears to have optimized will be determined by the additional costs of searching and whether there is a risk of starvation. We therefore compare the predictions of models based on currencies that consider only energy and predation risk to state-dependent models in which energy reserves are used to trade off predation rate, starvation rate and investment in growth. The choice of currency qualitatively affects how mode should change when prey abundance and prey patchiness increase. We show how differing prey distributions can explain variation in effects of experimentally increasing prey abundance. Our work has several implications for the study of foraging mode, population dynamics and the methods used to assess population size.Publisher PDFPeer reviewe

Current incentives for scientists lead to underpowered studies with erroneous conclusions

We can regard the wider incentive structures that operate across science – such as the priority given to novel findings – as an ecosystem within which scientists strive to maximise their fitness (i.e., publication record and career success). Here, we develop an optimality model that predicts the most rational research strategy, in terms of the proportion of research effort spent on seeking novel results rather than on confirmatory studies, and the amount of research effort per exploratory study. We show that, for parameter values derived from the scientific literature, researchers acting to maximise their fitness should spend most of their effort seeking novel results and conduct small studies that have only 10-40% statistical power. As a result, half of the studies they publish will report erroneous conclusions. Current incentive structures are in conflict with maximising the scientific value of research; we suggest ways that the scientific ecosystem could be improved

Analysis and evaluation of the environmental impacts of upstream petroleum operations

Sustainability is increasingly considered an essential business function, but in Libya, petroleum companies are slow to address operational issues that could reduce environmental concerns. This study aims to evaluate the environmental impacts of upstream petroleum operations. The methods adopted in the study are a literature review, an environmental impact assessment (EIA) study and qualitative analyses from, fieldwork trials and 56 semi-structured interviews. The results of the study show that the main environmental impacts are aquatic, terrestrial or atmospheric, with the most significant pollutants linked to the latter category, mainly from engine exhausts, turbine emissions, gas flaring and venting. Major environmental degradations are identified in Libyan upstream operations and a number of recommendations formulated minimising their effect. Particular importance is placed on establishing strict sustainability policies and regulations, and the implementation of an environmental management system

Evolution of a flexible rule for foraging that copes with environmental variation

PublishedThis is the final version of the article. It first appeared from Oxford University Press via http://www.currentzoology.org/paperdetail.asp?id=12437Models of adaptive behaviour typically assume that animals behave as though they have highly complex, detailed strategies for making decisions. In reality, selection favours the optimal balance between the costs and benefits of complexity. Here we investigate this trade-off for an animal that has to decide whether or not to forage for food - and so how much energy reserves to store - depending on the food availability in its environment. We evolve a decision rule that controls the target reserve level for different ranges of food availability, but where increasing complexity is costly in that metabolic rate increases with the sensitivity of the rule. The evolved rule tends to be much less complex than the optimal strategy but performs almost as well, while being less costly to implement. It achieves this by being highly sensitive to changing food availability at low food abun-dance - where it provides a close fit to the optimal strategy - but insensitive when food is plentiful. When food availability is high, the target reserve level that evolves is much higher than under the optimal strategy, which has implications for our under-standing of obesity. Our work highlights the important principle of generalisability of simple decision-making mechanisms, which enables animals to respond reasonably well to conditions not directly experienced by themselves or their ancestors.This work was supported by the European Research Council (Advanced Grant 250209 to A.I.H.) and a College for Life Sciences Fellowship at the Wissenschaftskolleg zu Berlin awarded to A.D.H

The evolution of mechanisms underlying behaviour

This is the final version of the article. It first appeared from Oxford University press via http://www.scopus.com/record/display.uri?eid=2-s2.0-84925394342&origin=inward&txGid=0-This work was funded by the European Research Council (Advanced Grant 250209 to Alasdair Houston)

Florivory as an opportunity benefit of aposematism

A.D.H. was supported by the European Research Council (Advanced Grant 250209 to A. Houston) and fellowships from the Wissenschaftskolleg zu Berlin and the Natural Environment Research Council (NE/L011921/1).Inconspicuous prey pay a cost of reduced feeding opportunities. Flowers are highly nutritious but are positioned where prey would be apparent to predators and often contain toxins to reduce consumption. However, many herbivores are specialized to subvert these defenses by retaining toxins for their own use. Here, we present a model of the growth and life history of a small herbivore that can feed on leaves or flowers during its development and can change its primary defense against visual predators between crypsis and warning coloration. When herbivores can retain plant toxins, their fitness is greatly increased when they are aposematic and can consume flowers. Thus, toxin sequestration leading to aposematism may enable a significant opportunity benefit for florivory. Florivory by cryptic herbivores is predicted when toxins are very potent but are at high concentration only in flowers and not in leaves. Herbivores should usually switch to eating flowers only when large and in most conditions should switch simultaneously from crypsis to aposematism. Our results suggest that florivory should be widespread in later instars of small aposematic herbivores and should be associated with ontogenic color change. Florivory is likely to play an underappreciated role in herbivorous insect life histories and host plant reproductive success.Publisher PDFPeer reviewe

The influence of the starvation-predation trade-off on the relationship between ambient temperature and body size among endotherms

Aim: The tendency for animals at higher latitudes to be larger (Bergmann's rule) is generally explained by recourse to latitudinal effects on ambient temperature and the food supply, but these receive only mixed support and do not explain observations of the inverse to Bergmann's rule. Our aim was to better understand how ecological variables might influence body size and thereby explain this mixed support. Location: World-wide. Methods: Previous explanations do not allow for the selective pressure exerted by the trade-off between predation and starvation, which we incorporate in a model of optimal body size and energy storage of a generalized homeotherm. In contrast to existing arguments, we concentrate on survival over winter when the food supply is poor and can be interrupted for short periods. Results: We use our model to assess the logical validity of the heat conservation hypothesis and show that it must allow for the roles of both food availability and predation risk. We find that whether the effect of temperature on body size is positive or negative depends on temperature range, predator density, and the likelihood of long interruptions to foraging. Furthermore, changing day length explains differing effects of altitude and latitude on body size, leading to opposite predictions for nocturnal and diurnal endotherms. Food availability and ambient temperature can have counteracting selective pressures on body mass, and can lead to a non-monotonic relationship between latitude and size, as observed in several studies. Main conclusions: Our work provides a theoretical framework for understanding the relationships between the costs and benefits of large body size and eco-geographical patterns among endotherms world-wide