CT angiography,underuse, overuse,or appropriate use?

Recently, cardiologists have started serious debates over expensive medical technologies, questioning the conclusions that high-resolution cardiac CT images are almost as effective as conventional angiograms. This debate reveals a deep gap among cardiologists over the use of multi-slice CT angiography. A number of physicians have immediately embraced CT technology and installed expensive CT scanners in their hospitals in order to detect early signs of coronary artery disease.     

Our use,misuse, and abandonment of a concept: Whither habitat?

The foundational concept of habitat lies at the very root of the entire science of ecology, but inaccurate use of the term compromises scientific rigor and communication among scientists and nonscientists. In 1997, Hall, Krausman & Morrison showed that ‘habitat’ was used correctly in only 55% of articles. We ask whether use of the term has been more accurate since their plea for standardization and whether use varies across the broader range of journals and taxa in the contemporary literature (1998–2012). We searched contemporary literature for ‘habitat’ and habitat‐related terms, ranking usage as either correct or incorrect, following a simplified version of Hall et al.'s definitions. We used generalized linear models to compare use of the term in contemporary literature with the papers reviewed by Hall et al. and to test the effects of taxa, journal impact in the contemporary articles and effects due to authors that cited Hall et al. Use of the term ‘habitat’ has not improved; it was still only used correctly about 55% of the time in the contemporary data. Proportionately more correct uses occurred in articles that focused on animals compared to ones that included plants, and papers that cited Hall et al. did use the term correctly more often. However, journal impact had no effect. Some habitat terms are more likely to be misused than others, notably ‘habitat type’, usually used to refer to vegetation type, and ‘suitable habitat’ or ‘unsuitable habitat’, which are either redundant or nonsensical by definition. Inaccurate and inconsistent use of the term can lead to (1) misinterpretation of scientific findings; (2) inefficient use of conservation resources; (3) ineffective identification and prioritization of protected areas; (4) limited comparability among studies; and (5) miscommunication of science‐based findings. Correct usage would improve communication with scientists and nonscientists, thereby benefiting conservation efforts, and ecology as a science.     

ω3 fatty acid desaturases from microorganisms: structure, function, evolution, and biotechnological use

The biosynthesis of very-long-chain polyunsaturated fatty acids involves an alternating process of fatty acid desaturation and elongation catalyzed by complex series of enzymes. ω3 desaturase plays an important role in converting ω6 fatty acids into ω3 fatty acids. Genes for this desaturase have been identified and characterized in a wide range of microorganisms, including cyanobacteria, yeasts, molds, and microalgae. Like all fatty acid desaturases, ω3 desaturase is structurally characterized by the presence of three highly conserved histidine-rich motifs; however, unlike some desaturases, it lacks a cytochrome b5-like domain. Understanding the structure, function, and evolution of ω3 desaturases, particularly their substrate specificities in the biosynthesis of very-long-chain polyunsaturated fatty acids, lays the foundation for potential production of various ω3 fatty acids in transgenic microorganisms.     

10,000 year history of plant use at Bosumpra Cave,Ghana

Investigations of hunter-gatherer subsistence, early food production, and the development of agroforestry systems during the Later Stone Age (LSA) of West Africa have proven challenging because of limited recovery and analysis of archaeological evidence relating directly to subsistence. This paper examines changes in the use of plant resources over a 10,000 year period at Bosumpra Cave, southern Ghana. Large quantities of recovered Canarium schweinfurthii (incense tree) and Elaeis guineensis (oil palm) endocarp preserved at the site allow for the assessment of previous observations about changes in the relative importance of tree fruit resources over time. Results point to the possibility that C. schweinfurthii was a managed resource and may be useful as a marker of forager subsistence in tropical forest regions. The exploitation of C. schweinfurthii persisted in the early and middle Holocene, but was eventually overshadowed in the late Holocene by Kintampo food-producing economies based on Pennisetum glaucum (pearl millet), Vigna unguiculata (cowpea) and E. guineensis. The Bosumpra deposits also yielded domesticated pearl millet and cowpea, allowing for the comparison of LSA hunter-gatherer and early food producer subsistence practices and cultural interactions in southern Ghana.     

Tapping women’s knowledge: Plant resource use in extractive reserves,acre, Brazil

Tapping into the vast pool of existing plant resource knowledge is the first step toward developing production systems that successfully balance ecological, economic, and cultural concerns in the newly formed extractive reserves in Acre, Brazil. Field research targeting extractive activities by women in the forest communities identified the most common species used by women, and documented specific information on the management, collection, and processing of these plants. The women demonstrate refined botanical knowledge and plant management skills, exploiting over 150 wild and domesticated species in their communities. They possess particular proficiency in processing plants, especially species used for food, spices, beverages, and medicines. Women also display a great desire to enter the market economy, and have begun to test potential market products on a small scale. As such they can play a key role in production, diversification, and development of economically valuable plant products, and ultimately in the success of the extractive reserves.     

Food,microhabitat, or both? Macroinvertebrate use of leaf accumulations in a montane stream

1. Leaf packs in streams may serve as food and substrate to many macroinvertebrates, but the relative importance of these two functions has not been disentangled. To test the hypothesis that leaf packs are colonized primarily for their food value rather than as microhabitat, the colonization of leaf packs of red alder and of polyester cloth in a natural stream was compared. 2. Species of shredders showed large differences in the colonization of the two types of leaf pack with almost no use of artificial leaf packs. Non-shredders were also more abundant on natural leaf packs, however, they colonized artificial leaf packs six to eighty times proportionally more than shredders. 3. The effect of different leaf types was virtually eliminated for non-shredders when the amount of fine parriculate detritus (food for many non-shredders) trapped in the leaf pack was added to the analysis as a covariate. Therefore, to non-shredders, leaf types differed only in the retention of fine particulate organic matter. 4. Comparisons of the use of both kinds of leaf packs in riffles versus pools revealed that significantly fewer animals colonized pool leaf packs. 5. These results suggest that food value, and not microhabitat, is the primary determinant of leaf pack use for most shredders and non-shredders.     

β-alanine use by Ebony and normal Drosophila melanogaster with notes on glucose,uracil, dopa,and dopamine

Following injection of newly formed female pupae or adult Drosophila with C ¹⁴ -labeled -alanine, appreciable labeled free -alanine was retained in the internal organs for at least 24 hr. Ebony retained most, while heterozygotes were intermediate. Part of the -alanine-2-C-labeled portion of the molecule was bound to the internal organs, especially the ovaries and mature egg follicles. Dissected normal pupal cuticles incorporate -alanine-1-C as directly related to the degree of tanning. KCN, ethanol, or air exclusion inhibit incorporation. Tan pigment and radioactivity are extractable from the cuticles by hydrazine-ethanol. A -alanine precursor is uracil. Injected -alanine immobilizes ebony, but not normal, flies (newly emerged) and inhibits glucose, but not glucose 6-phosphate metabolism. Desiccated ebony adults take up water more readily than normal adults.Aided by Public Health Service Award GM 12435.     

Biodiversity and land use change on the Causse Méjan, France

This paper argues that due to the co-evolution of biological and cultural diversity, a meaningful study of biodiversity must be positioned within complex social-ecological systems. A complex systems framework is proposed for conceptualising the study of social-ecological systems. A case study approach is adopted whereby changes in biodiversity on the Causse Méjan, France, are linked with changes in society, land use, agricultural practices and policies. We argue that ecological and social resilience is linked through the dependence on ecosystems of communities, and in turn by the influence of institutional structures, including market forces, on the use of natural resources. Within a non-equilibrium evolutionary perspective, we highlight the difficulty of choosing a landscape and biodiversity of reference and postulating that it is in equilibrium with a type of social organisation. We conclude by exploring an ‘adaptive management’ approach to the management of the biodiverse landscape studied.     

Weather conditions and daily television use in the Netherlands, 1996–2005

This study examines the impact of daily atmospheric weather conditions on daily television use in the Netherlands for the period 1996–2005. The effects of the weather parameters are considered in the context of mood and mood management theory. It is proposed that inclement and uncomfortable weather conditions are associated with lower human mood, and that watching entertainment and avoiding informational programs may serve to repair such mood. We consequently hypothesize that people spend more time watching television if inclement and uncomfortable weather conditions (low temperatures, little sunshine, much precipitation, high wind velocity, less daylight) coincide with more airtime for entertainment programs, but that they view less if the same weather conditions coincide with more airtime devoted to information fare. We put this interaction thesis to a test using a time series analysis of daily television viewing data of the Dutch audience obtained from telemeters (T = 3,653), merged with meteorological weather station statistics and program broadcast figures, whilst controlling for a wide array of recurrent and one-time societal events. The results provide substantial support for the proposed interaction of program airtime and the weather parameters temperature and sunshine on aggregate television viewing time. Implications of the findings are discussed.     

Central European Greylag Geese Anser anser show a shortening of migration distance and earlier spring arrival over 60 years

Global climate change can cause pronounced changes in species? migratory behaviour. Numerous recent studies have demonstrated climate‐driven changes in migration distance and spring arrival date in waterbirds, but detailed studies based on long‐term records of individual recapture or re‐sighting events are scarce. Using re‐sighting data from 430 marked individuals spanning a 60‐year period (winters 1956/1957 to 2015/2016), we assessed patterns in migration distance and spring arrival date, wintering‐site fidelity and survival in the increasing central European breeding population of Greylag Geese Anser anser. We demonstrate a long‐term decrease in migration distance, changes in the wintering range caused by winter partial short‐stopping, and the earlier arrival of geese on their breeding grounds. Greylag Geese marked on central Europe moulting grounds have not been recorded wintering in Spain since 1986 or in Tunisia and Algeria since 2004. The migration distance and spring arrival of geese indicated an effect of temperature at the breeding site and values of the NAO index. Greylag Geese migrate shorter distances and arrive earlier in milder winters. We suggest that shifts in the migratory behaviour of Central European Greylag Geese are individual temperature‐dependent decisions to take advantage of wintering grounds becoming more favourable closer to their breeding grounds, allowing birds to acquire breeding territories earlier.     

Overtaking on migration: does longer distance migration always incur a penalty?

For many migratory bird species, the latitudinal range of the winter distribution spans thousands of kilometres, thus encompassing considerable variation in individual migration distances. Pressure to winter near breeding areas is thought to be a strong driver of the evolution of migration patterns, as individuals undertaking a shorter migration are generally considered to benefit from earlier arrival on the breeding grounds. However, the influence of migration distance on timing of arrival is difficult to quantify because of the large scales over which individuals must be tracked. Using a unique dataset of individually‐marked Icelandic black‐tailed godwits Limosa limosa islandica tracked throughout the migratory range by a network of hundreds of volunteer observers, we quantify the consequences of migrating different distances for the use of stop‐over sites and timing of arrival in Iceland. Modelling of potential flight distances and tracking of individuals from across the winter range shows that individuals wintering further from the breeding grounds must undertake a stop‐over during spring migration. However, despite travelling twice the distance and undertaking a stop‐over, individuals wintering furthest from the breeding grounds are able to overtake their conspecifics on spring migration and arrive earlier in Iceland. Wintering further from the breeding grounds can therefore be advantageous in migratory species, even when this requires the use of stop‐over sites which lengthen the migratory journey. As early arrival on breeding sites confers advantages for breeding success, the capacity of longer distance migrants to overtake conspecifics is likely to influence the fitness consequences of individual migration strategies. Variation in the quality of wintering and stopover sites throughout the range can therefore outweigh the benefits of wintering close to the breeding grounds, and may be a primary driver of the evolution of specific migration routes and patterns.     

Forage plants of an Arctic‐nesting herbivore show larger warming response in breeding than wintering grounds,potentially disrupting migration phenology

During spring migration, herbivorous waterfowl breeding in the Arctic depend on peaks in the supply of nitrogen‐rich forage plants, following a “green wave” of grass growth along their flyway to fuel migration and reproduction. The effects of climate warming on forage plant growth are expected to be larger at the Arctic breeding grounds than in temperate wintering grounds, potentially disrupting this green wave and causing waterfowl to mistime their arrival on the breeding grounds. We studied the potential effect of climate warming on timing of food peaks along the migratory flyway of the Russian population of barnacle geese using a warming experiment with open‐top chambers. We measured the effect of 1.0–1.7°C experimental warming on forage plant biomass and nitrogen concentration at three sites along the migratory flyway (temperate wintering site, temperate spring stopover site, and Arctic breeding site) during 2 months for two consecutive years. We found that experimental warming increased biomass accumulation and sped up the decline in nitrogen concentration of forage plants at the Arctic breeding site but not at temperate wintering and stop‐over sites. Increasing spring temperatures in the Arctic will thus shorten the food peak of nitrogen‐rich forage at the breeding grounds. Our results further suggest an advance of the local food peak in the Arctic under 1–2°C climate warming, which will likely cause migrating geese to mistime their arrival at the breeding grounds, particularly considering the Arctic warms faster than the temperate regions. The combination of a shorter food peak and mistimed arrival is likely to decrease goose reproductive success under climate warming by reducing growth and survival of goslings after hatching.     

The onset of spring and timing of migration in two arctic nesting goose populations: the pink‐footed goose Anser bachyrhynchus and the barnacle goose Branta leucopsis

An earlier onset of spring has been recorded for many parts of Eurasia in recent decades. This has consequences for migratory species, both in changing the conditions encountered by individuals on reaching migratory sites and in affecting cues regulating the timing of migration where decisions to migrate are influenced by local environmental variables. Here we examine the timing of spring migration for two arctic goose populations, the pink‐footed goose Anser brachyrhynchus (during 1990–2003) and barnacle goose Branta leucopsis (during 1982–2003), which both breed on Svalbard. The satellite‐derived Normalised Difference Vegetation Index (NDVI) was used to express the onset of spring at their wintering and spring staging sites. Pink‐footed geese use several sites during spring migration, ranging from the southernmost wintering areas in Belgium to two spring staging areas in Norway, and distances between sites used along the flyway are relatively short. There was a positive correlation in the onset of spring between neighbouring sites, and the geese migrated earlier in early springs. Barnacle geese, on the other hand, have a long overseas crossing from their wintering grounds in Britain to spring staging areas in Norway. Although spring advanced in both regions, there was no corresponding correlation in the timing of onset of spring between their wintering and spring staging sites, and little evidence for barnacle geese migrating earlier over the whole study period. Hence, where geese can use spring conditions at one site as an indicator of the conditions they might encounter at the next, they have responded quickly to the advancement of spring, whereas in a situation where they cannot predict, they have not yet responded, despite the advancement of spring in the spring staging area.     

西藏南部羊卓雍错水鸟群落及斑头雁活动区域特征

2009年4月至2010年1月,对西藏南部羊卓雍错的水鸟资源状况进行了调查。采用定点观察的方法,沿湖选择了24个观察点,分别在繁殖前期、中期和后期,以及秋季和冬季进行了6次调查。采用核密度分析(Kernel analysis)的方法,对两只卫星跟踪斑头雁(Anser indicus)的活动区进行了分析。调查期间,记录到水鸟32种31044只,隶属于6目10科。雁鸭类和鸥类分别占水鸟总数73.9%和19.1%,主要是斑头雁、赤嘴潜鸭(Rhodonessa rufina)、赤麻鸭(Tadorna ferruginea)、棕头鸥(Larus brunnicephalus)等。水鸟多样性较高的季节是春秋迁徙季节。羊卓雍错夏季主要的繁殖种群是斑头雁和棕头鸥,也有少量黑颈鹤(Grus nigricollis)的繁殖个体;冬季主要物种是赤嘴潜鸭,经常聚集在融化的冰面上。春季斑头雁的数量增加趋势较为明显;进入繁殖期后,斑头雁处于孵卵阶段,繁殖种群的数量达到2000余只;繁殖后期,斑头雁换羽结束,成鸟带领幼鸟在鸟岛附近的湖边取食,此时观察到斑头雁的数量又有明显的增加;秋季斑头雁的南迁致使种群数量呈下降趋势;冬季许多斑头雁从北方如青海湖等地迁来越冬使得种群数量有所增加,多分布于湖西浪卡子县城附近的沼泽湿地和湖南部的绒波臧布河流的入口处。卫星跟踪结果表明,羊卓雍错是青海湖繁殖的斑头雁重要的越冬地之一,湖西部沼泽湿地和湖南部的河流入口处是其主要活动区域,而且该湖与雅鲁藏布江河谷之间通过斑头雁的往来移动存在着联系,因而是西藏南部禽流感监测的重要地点。     

The strength of migratory connectivity for birds en route to breeding through the Gulf of Mexico

The strength of migratory connectivity is a measure of the cohesion of populations among phases of the annual cycle, including breeding, migration, and wintering. Many Nearctic‐Neotropical species have strong migratory connectivity between breeding and wintering phases of the annual cycle. It is less clear if this strength persists during migration when multiple endogenous and exogenous factors may decrease the cohesion of populations among routes or through time along the same routes. We sampled three bird species, American redstart Setophaga ruticilla, ovenbird Seiurus aurocapilla, and wood thrush Hylocichla mustelina, during spring migration through the Gulf of Mexico region to test if breeding populations differentiate spatially among migration routes or temporally along the same migration routes and the extent to which within‐population timing is a function of sex, age, and carry‐over from winter habitat, as measured by stable carbon isotope values in claws (δ¹³C). To make quantitative comparisons of migratory connectivity possible, we developed and used new methodology to estimate the strength of migratory connectivity (MC) from probabilistic origin assignments identified using stable hydrogen isotopes in feathers (δ²H). We found support for spatial differentiation among routes by American redstarts and ovenbirds and temporal differentiation along routes by American redstarts. After controlling for breeding origin, the timing of American redstart migration differed among ages and sexes and ovenbird migration timing was influenced by carry‐over from winter habitat. The strength of migratory connectivity did not differ among the three species, with each showing weak breeding‐to‐spring migration MC relative to prior assessments of breeding‐wintering connectivity. Our work begins to fill an essential gap in methodology and understanding of the extent to which populations remain together during migration, information critical for a full annual cycle perspective on the population dynamics and conservation of migratory animals.     

Seagrass (Zostera spp.) as food for brent geese (Branta bernicla): an overview

Brent geese (called brant in North America) are among the smallest and the most marine of all goose species, and they have very long migration routes between high Arctic breeding grounds and temperate wintering grounds. Like all other geese, brent geese are almost entirely herbivorous. Because of these ecological characteristics they have a high food demand and are strongly dependent on stopover sites to ”refuel” during the migration period. Three subspecies of brent geese are distributed around the Holarctic, forming seven populations with distinct migration routes. Most or all of these populations make heavy use of Zostera spp. during migratory stopovers on spring and/or autumn migration. Examples of Zostera stopover areas being used by large numbers of brent geese for several weeks each year are Izembek Lagoon (Alaska), lagoons in Baja California, the German/Danish Wadden Sea, the Golfe du Morbihan (France), British estuaries, and the White Sea (Western Russian Arctic). Brent geese feed on Zostera wherever they can, but they can only reach the plants at low tide or in shallow water. Changes in Zostera abundance affect brent goose distribution, and the ”wasting disease” affecting Atlantic Zostera stocks during the 1930s was at least partly responsible for a steep decline in brent goose population sizes on both sides of the Atlantic. While Zostera is of outstanding importance as food for brent geese, the impact of the geese on Zostera stocks seems to be less important – at many sites, the geese consume only a small amount of the available Zostera, or, if they consume more, the seagrass can regenerate fully until the following season. Received: 6 December 1998 / Received in revised form: 6 August 1999 / Accepted: 9 August 1999     

Light‐level geolocators reveal migratory connectivity in European populations of pied flycatchers Ficedula hypoleuca

Understanding what drives or prevents long‐distance migrants to respond to environmental change requires basic knowledge about the wintering and breeding grounds, and the timing of movements between them. Both strong and weak migratory connectivity have been reported for Palearctic passerines wintering in Africa, but this remains unknown for most species. We investigated whether pied flycatchers Ficedula hypoleuca from different breeding populations also differ in wintering locations in west‐Africa. Light‐level geolocator data revealed that flycatchers from different breeding populations travelled to different wintering sites, despite similarity in routes during most of the autumn migration. We found support for strong migratory connectivity showing an unexpected pattern: individuals breeding in Fennoscandia (S‐Finland and S‐Norway) wintered further west compared to individuals breeding at more southern latitudes in the Netherlands and SW‐United Kingdom. The same pattern was found in ring recovery data from sub‐Saharan Africa of individuals with confirmed breeding origin. Furthermore, population‐specific migratory connectivity was associated with geographical variation in breeding and migration phenology: birds from populations which breed and migrate earlier wintered further east than birds from ‘late’ populations. There was no indication that wintering locations were affected by geolocation deployment, as we found high repeatability and consistency in δ¹³C and δ¹⁵N stable isotope ratios of winter grown feathers of individuals with and without a geolocator. We discuss the potential ecological factors causing such an unexpected pattern of migratory connectivity. We hypothesise that population differences in wintering longitudes of pied flycatchers result from geographical variation in breeding phenology and the timing of fuelling for spring migration at the wintering grounds. Future research should aim at describing how temporal dynamics in food availability across the wintering range affects migration, wintering distribution and populations’ capacity to respond to environmental changes.     

Environmental conditions at arrival to the wintering grounds and during spring migration affect population dynamics of barn swallows Hirundo rustica breeding in Northern Italy

Several populations of long-distance migratory birds are currently suffering steep demographic declines. The identification of the causes of such declines is difficult because population changes may be driven by events occurring in distant geographical areas during different phases of the annual life-cycle of migrants. Furthermore, wintering areas and migration routes of populations of small-sized species are still largely unknown, with few exceptions. In this paper we identified the critical phases of the annual life-cycle that most influence the population dynamics of a small passerine, the Barn Swallow Hirundo rustica. We used information on temporal dynamics of a population breeding in Northern Italy, whose wintering range and timing of migration have been recently described by miniaturised tracking dataloggers. Our results indicated that primary productivity in the wintering grounds in the month when most individuals arrive from autumn migration and primary productivity in an area that is probably a stopover site during spring migration, influenced population dynamics more than habitat conditions at the breeding grounds. By using annual variation in primary productivity at the wintering grounds and stopover sites as predictors, we replicated the observed interannual population changes with great accuracy. However, the steep decline recently suffered by the population could be replicated only by including a constant annual decline in the model, suggesting that changes in primary productivity only predicted the interannual variation around the long-term trend. Our study therefore suggests the existence of critical periods during wintering and migration that may have large impact on population fluctuations of migrant birds.     

The pull of the Central Flyway? Veeries breeding in western Canada migrate using an ancestral eastern route

Understanding non‐breeding season movements and identifying wintering areas of different populations of migratory birds is important for establishing patterns of migratory connectivity over the annual cycle. We analyzed archival solar geolocation (N = 5) and global positioning data (N = 1) to investigate migration routes, stopover sites, and wintering areas of a western‐most breeding population of Veeries (Catharus fuscescens) in the Pemberton Valley, British Columbia, Canada. Geolocation data were analyzed using a Bayesian state‐space model to improve likely position estimates. We compared our results with those from a Veery population located ~250 km east across a mountain chain in the Okanagan Valley, British Columbia, and with an eastern population in Delaware, U.S.A. Migrating Veeries from the Pemberton Valley used an eastern trajectory through the Rocky Mountains to the Great Plains to join a central flyway during fall and spring migration, a route similar to that used by Veeries breeding in the Okanagan Valley. However, wintering destinations of Pemberton Valley birds were more varied, with inter‐individual wintering distances ~1000 km greater than birds from the Okanagan Valley population and ~500 km from the previously known winter range of Veeries. The observed eastern migration path likely follows an ancestral route that evolved following the most recent glacial retreat. Consistent with patterns observed from the Okanagan and Delaware populations, Veeries from the Pemberton Valley undertook an intra‐tropical migration on the wintering grounds, but this winter movement differed from those of previously studied populations. Such winter movements may thus be idiosyncratic or show coarse population associations. Intra‐wintering‐ground movements likely occur either in response to seasonal changes in habitat suitability or as a means of optimizing pre‐migratory fueling prior to long‐distance spring movements to North America.