1,209 research outputs found
Conflicts between reindeer herding and an expanding caribou herd in Alaska
The reindeer industry has existed in Alaska since 1892. This industry has largely been concentrated on the Seward Peninsula, Alaska because suitable habitat has been available and caribou have been absent here for over 100 years. Until recently, reindeer meat and velvet antler production consistently generated millions of dollars in revenue critical to the economies of rural Alaskan communities. From 1976 to 1996 the Western Arctic Caribou Herd (WACH) increased from about 75 000 to 463 000 animals. Concurrently, seasonal range use of the WACH shifted westward onto traditional reindeer ranges of the Seward Peninsula. Reindeer herders lost 75-100% of their herds through commingling and out¬migration with wild caribou. This loss of over 12 000 reindeer represents a potential economic value of 13 million dollars. Sustainable meat and velvet antler production and the economies of western Alaskan are likely to be affected by these changes
Effects of Gas Flaring on the Behavior of Night-migrating Birds at an Artificial Oil-production Island, Arctic Alaska
We studied movement rates and the general flight behavior of bird flocks seen on radar and recorded visually at Northstar Island, Arctic Alaska, from 13 to 27 September 2002. Most of this period (13 â 19 and 21 â 27 September) had no gas-flaring events, but a major gas-flaring event occurred on the night of 20 September. Movement rates of targets on radar and of bird flocks recorded visually in the first ~50% â 60% of the night were much lower during the non-flaring period than during the night of flaring, whereas rates in the last ~40% â 50% of the night were similar in all periods. The general flight behavior of birds also differed significantly, with higher percentages of both radar targets and bird flocks exhibiting straight-line (directional) flight behaviors during the non-flaring periods and higher percentages of radar targets and bird flocks exhibiting non-straight-line (erratic and circling) flight behaviors during the gas-flaring period. During the night of gas flaring, the bright illumination appeared to have an effect only after sunset, when flocks of birds circled the island after being drawn in from what appeared to be a substantial distance from the island. On both radar and visual sampling, the number of bird flocks approaching the island declined over the evening, and the attractiveness of the light from flaring appeared to decline. The visibility of the moon appeared to have little effect on the behavior of birds. Because illumination from extensive gas-flaring is such a strong attractant to migrating birds and because most bird flocks fly at low altitudes over the water, flaring booms on coastal and offshore oil-production platforms in Arctic Alaska should be positioned higher than the mean flight altitudes of migrating birds to reduce the chances of incineration.Nous avons Ă©tudiĂ© les taux de dĂ©placement et le comportement de vol gĂ©nĂ©ral des troupeaux dâoiseaux captĂ©s par radar ou consignĂ©s visuellement Ă lâĂźle Northstar, dans lâAlaska de lâArctique, du 13 au 27 septembre 2002. Pendant presque toute cette pĂ©riode (du 13 au 19 et du 21 au 27 septembre), il nây a pas eu de brĂ»lage de gaz Ă la torche, mais la nuit du 20 septembre, il y a eu un important brĂ»lage de gaz Ă la torche. Les taux de dĂ©placement des cibles radar et des troupeaux dâoiseaux consignĂ©s visuellement pendant la premiĂšre tranche dâenviron 50 % Ă 60 % de la nuit Ă©taient beaucoup moins Ă©levĂ©s pendant la pĂ©riode oĂč il nây avait pas de brĂ»lage Ă la torche que pendant la nuit oĂč il y a eu brĂ»lage Ă la torche, tandis que pendant la deuxiĂšme tranche dâenviron 40 % Ă 50 % de la nuit, les taux de dĂ©placement Ă©taient semblables pendant toutes les pĂ©riodes. Le comportement de vol gĂ©nĂ©ral des oiseaux a Ă©galement affichĂ© une diffĂ©rence considĂ©rable. De plus grands pourcentages de cibles radar et de troupeaux dâoiseaux adoptaient un comportement de vol rectiligne (direct) pendant les pĂ©riodes oĂč il nây avait pas de brĂ»lage Ă la torche, et de plus grands pourcentages de cibles radar et de troupeaux dâoiseaux affichaient un comportement de vol non rectiligne (erratique et indirect) pendant la pĂ©riode oĂč il y a eu brĂ»lage Ă la torche. La nuit du brĂ»lage Ă la torche, la vive illumination nâa semblĂ© avoir un effet quâaprĂšs le coucher du soleil, quand les troupeaux dâoiseaux encerclaient lâĂźle aprĂšs avoir Ă©tĂ© attirĂ©s depuis un endroit qui semblait trĂšs lointain. Tant pour lâĂ©chantillonnage prĂ©levĂ© par radar que par consignation visuelle, le nombre de troupeaux dâoiseaux sâapprochant de lâĂźle diminuait dans le courant de la soirĂ©e, et lâattrait de la lumiĂšre Ă©manant du brĂ»lage Ă la torche semblait Ă©galement diminuer. La visibilitĂ© de la lune semblait avoir peu dâeffet sur le comportement des oiseaux. Puisque lâillumination provenant du brĂ»lage prolongĂ© Ă la torche exerce une si grande force dâattraction chez les oiseaux migrateurs, et puisque la plupart des troupeaux dâoiseaux volent en basse altitude au-dessus de lâeau, le torchage effectuĂ© sur les plateformes pĂ©troliĂšres cĂŽtiĂšres et extracĂŽtiĂšres dans lâAlaska de lâArctique devrait ĂȘtre positionnĂ© plus haut que les altitudes moyennes de vol des oiseaux migrateurs afin de rĂ©duire les risques dâincinĂ©ration
Effects of a Hazing-Light System on Migration and Collision Avoidance of Eiders at an Artificial Oil-Production Island, Arctic Alaska
During migration, Common and King Eiders (Somateria mollissima and S. spectabilis) cross the Beaufort and Chukchi Seas of Arctic Alaska. Because they may become attracted to lights, eiders are susceptible to collision with structures, including offshore oil facilities. We used ornithological radar in 2001 â 04 to characterize the behavior of eiders migrating past Northstar Island, an oil-production island near Prudhoe Bay, Alaska, and to assess the effects of a hazing-light system on migrating eiders. âEiderâ radar targets exhibited pulsed, irregular periods of movement; movement rates were higher when sea ice was present, without precipitation, and during tailwinds and crosswinds but were not affected by lights. Velocities (ground speeds) were higher when ice was present and with strong tailwinds. They were lower at night when the lights were on, but higher during the day when the lights were on. Radar targets exhibited little variation in flight behavior as they passed the island; the proportion of non-directional behavior was larger when ice was present, with tailwinds, with weak winds, and near the full moon when it was not visible. Lights had no effect on flight behavior. Birds tended to exhibit more course changes as they approached the island, greater angular changes when they changed course, and larger net increases in passing distance as a result of those course changes when the lights were on; however, none of these differences were statistically significant. Overall, the hazing lights at Northstar did not disrupt the birdsâ migratory movements but resulted in increased avoidance of the island.En pĂ©riode de migration, lâeider Ă duvet et lâeider Ă tĂȘte grise (Somateria mollissima et S. spectabilis) survolent la mer de Beaufort et la mer des Tchouktches dans lâAlaska de lâArctique. Comme ils sont attirĂ©s par les lumiĂšres, les eiders risquent dâentrer en collision avec des structures, y compris les installations pĂ©troliĂšres au large. De 2001 Ă 2004, nous avons utilisĂ© un radar ornithologique pour caractĂ©riser le comportement des eiders qui migrent au-delĂ de lâĂźle Northstar, une Ăźle de production pĂ©troliĂšre prĂšs de Prudhoe Bay, en Alaska, et pour Ă©valuer les effets dâun systĂšme dâĂ©clairage de dispersion sur les eiders en migration. Les « eiders » ciblĂ©s par le radar prĂ©sentaient des pĂ©riodes de mouvement pulsĂ©es et irrĂ©guliĂšres; les taux de mouvement Ă©taient plus importants en prĂ©sence de glace marine, en lâabsence de prĂ©cipitation et en prĂ©sence de vent arriĂšre et de vent latĂ©ral, mais nâĂ©taient pas touchĂ©s par les lumiĂšres. Les vĂ©locitĂ©s (vitesses au sol) Ă©taient plus Ă©levĂ©es en prĂ©sence de glace et de forts vents arriĂšre. Elles Ă©taient plus basses la nuit lorsque les lumiĂšres Ă©taient allumĂ©es, mais plus Ă©levĂ©es le jour lorsque les lumiĂšres Ă©taient allumĂ©es. Nous avons observĂ© peu de variation quant au comportement de vol des cibles atteintes par le radar pendant quâelles survolaient lâĂźle; la proportion de comportements de vol non directionnels Ă©tait plus importante en prĂ©sence de glace, de vent arriĂšre, de vent faible et lorsque la pleine lune nâĂ©tait pas visible. Les lumiĂšres nâont pas eu dâimpact sur le comportement de vol. Lorsque les lumiĂšres Ă©taient allumĂ©es, les oiseaux avaient tendance Ă changer de direction plus souvent durant leur vol Ă lâapproche de lâĂźle et Ă effectuer de plus grandes variations angulaires lorsquâils changeaient de direction, puis prĂ©sentaient une nette augmentation de la distance de passage Ă la suite de ces changements de direction. Toutefois, aucune de ces diffĂ©rences nâĂ©tait statistiquement importante. En gĂ©nĂ©ral, les lumiĂšres de dispersion de lâĂźle Northstar nâont pas nui aux mouvements migratoires des oiseaux, mais ces derniers ont davantage Ă©vitĂ© de voler prĂšs de lâĂźle
Taxing the Informal Economy: The Current State of Knowledge and Agendas for Future Research
This paper reviews the literature on taxation of the informal economy, taking stock of key debates
and drawing attention to recent innovations. Conventionally, the debate on whether to tax has frequently focused
on the limited revenue potential, high cost of collection, and potentially adverse impact on small firms. Recent
arguments have increasingly emphasised the more indirect benefits of informal taxation in relation to economic
growth, broader tax compliance, and governance. More research is needed, we argue, into the relevant costs and
benefits for all, including quasi-voluntary compliance, political and administrative incentives for reform, and
citizen-state bargaining over taxation
Child sexual abuse material in child-centred institutions: situational crime prevention approaches
This paper focuses on the potential for child-centred institutions to use situational crime prevention (SCP) strategies to prevent or reduce child sexual abuse material (CSAM)1 offending as a distinct form of child sexual abuse (CSA). We discuss the failure of the Royal Commission into Institutional Responses to Child Sexual Abuse in Australia to address the potential for CSAM offending to occur in child-centred institutions. Our premise is that CSAM offending is markedly shaped by the situation in which it occurs, rather than by any pre-existing preparedness to offend sexually against children. In this context, SCP for CSAM offending must be considered as part of overall strategies to combat CSA in institutional settings. However, we acknowledge that effective implementation of SCP in this area is not straightforward. We consider some of the challenges in implementing SCP at an institutional level
Test your surrogate data before you test for nonlinearity
The schemes for the generation of surrogate data in order to test the null
hypothesis of linear stochastic process undergoing nonlinear static transform
are investigated as to their consistency in representing the null hypothesis.
In particular, we pinpoint some important caveats of the prominent algorithm of
amplitude adjusted Fourier transform surrogates (AAFT) and compare it to the
iterated AAFT (IAAFT), which is more consistent in representing the null
hypothesis. It turns out that in many applications with real data the
inferences of nonlinearity after marginal rejection of the null hypothesis were
premature and have to be re-investigated taken into account the inaccuracies in
the AAFT algorithm, mainly concerning the mismatching of the linear
correlations. In order to deal with such inaccuracies we propose the use of
linear together with nonlinear polynomials as discriminating statistics. The
application of this setup to some well-known real data sets cautions against
the use of the AAFT algorithm.Comment: 14 pages, 15 figures, submitted to Physical Review
Measuring Information Transfer
An information theoretic measure is derived that quantifies the statistical
coherence between systems evolving in time. The standard time delayed mutual
information fails to distinguish information that is actually exchanged from
shared information due to common history and input signals. In our new
approach, these influences are excluded by appropriate conditioning of
transition probabilities. The resulting transfer entropy is able to distinguish
driving and responding elements and to detect asymmetry in the coupling of
subsystems.Comment: 4 pages, 4 Figures, Revte
Multifaceted needs of individuals living with peripheral arterial disease: a qualitative study
Objectives
To ascertain a comprehensive perspective of the impact of peripheral arterial disease (PAD) on people including needs for access to disease specific information, education, services, and support.
Methods
Participants were recruited from outpatient clinics at a tertiary hospital in metropolitan Australia. Telephone and face-to-face semi-structured interviews were conducted with nine individuals living with PAD and analysed using qualitative content thematic analysis.
Results
The nine participants were on average 74.2 (SD 10.9) years and predominantly women (67%). Lack of understanding of PAD and inconsistent information resulted in confusion regarding self-management strategies. Effects of pain and mobility problems were amplified for participants who lived alone and did not have an informal carer.
Discussion
Poor quality of life in PAD reflects pain, social isolation and fear of falls. Multidisciplinary teams with case managers should consider older peopleâs living situations and needs for additional support services and education to facilitate integrated care
Inter-species variation in colour perception
Inter-species variation in colour perception poses a serious problem for the view that colours are mind-independent properties. Given that colour perception varies so drastically across species, which species perceives colours as they really are? In this paper, I argue that all do. Specifically, I argue that members of different species perceive properties that are determinates of different, mutually compatible, determinables. This is an instance of a general selectionist strategy for dealing with cases of perceptual variation. According to selectionist views, objects simultaneously instantiate a plurality of colours, all of them genuinely mind-independent, and subjects select from amongst this plurality which colours they perceive. I contrast selectionist views with relationalist views that deny the mind-independence of colour, and consider some general objections to this strategy
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