scholarly journals The interplay of wind and uplift facilitates over-water flight in facultative soaring birds

2021 ◽  
Vol 288 (1958) ◽  
pp. 20211603
Author(s):  
Elham Nourani ◽  
Gil Bohrer ◽  
Paolo Becciu ◽  
Richard O. Bierregaard ◽  
Olivier Duriez ◽  
...  
Keyword(s):  
Migratory Birds ◽  
Global Scale ◽  
Atmospheric Conditions ◽  
Wind Uplift ◽  
Ecological Barriers ◽  
Open Sea ◽  
Spatio Temporal ◽  
Wind Support

Flying over the open sea is energetically costly for terrestrial birds. Despite this, over-water journeys of many birds, sometimes hundreds of kilometres long, are uncovered by bio-logging technology. To understand how these birds afford their flights over the open sea, we investigated the role of atmospheric conditions, specifically wind and uplift, in subsidizing over-water flight at a global scale. We first established that Δ T , the temperature difference between sea surface and air, is a meaningful proxy for uplift over water. Using this proxy, we showed that the spatio-temporal patterns of sea-crossing in terrestrial migratory birds are associated with favourable uplift conditions. We then analysed route selection over the open sea for five facultative soaring species, representative of all major migratory flyways. The birds maximized wind support when selecting their sea-crossing routes and selected greater uplift when suitable wind support was available. They also preferred routes with low long-term uncertainty in wind conditions. Our findings suggest that, in addition to wind, uplift may play a key role in the energy seascape for bird migration that in turn determines strategies and associated costs for birds crossing ecological barriers such as the open sea.

scholarly journals Sea-crossing along migratory flyways is limited more strongly by wind than by lack of uplift

2020 ◽  
Author(s):  
Elham Nourani ◽  
Paolo Becciu ◽  
Richard O. Bierregaard ◽  
Olivier Duriez ◽  
Sinos Giokas ◽  
...  
Keyword(s):  
Animal Movement ◽  
Migratory Birds ◽  
Bird Species ◽  
Temporal Distribution ◽  
Global Scale ◽  
Route Selection ◽  
Atmospheric Conditions ◽  
Ecological Barriers ◽  
Open Sea ◽  
Spatio Temporal

AbstractThe open sea is considered an ecological barrier to terrestrial bird movement. However, over-water journeys of many terrestrial birds, sometimes hundreds of kilometers long, are being uncovered by bio-logging technology. To understand how these birds afford their flights over the open sea, we investigated the role of atmospheric conditions in subsidizing sea-crossing behavior at the global scale. By analyzing forty years of temperature data, we show that the spatio-temporal patterns of sea-crossing in terrestrial migratory birds correspond to favorable uplift conditions. We then analyzed route selection over the open sea for four bird species with varying levels of dependence on soaring flight, representing all major migratory flyways worldwide. Our results showed that favorable uplift conditions, albeit not as common and powerful as over land, are not rare over the open seas and oceans. Moreover, wind, which is more variable than uplift in its spatio-temporal distribution, is the determining factor in the birds’ route selection over the open sea. Our findings suggest a need for revisiting how ecological barriers are defined, to reflect what we know of animal movement in the era of bio-logging.

Innovatory role of nanomaterials as bio-tools for treatment of cancer

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Khuram Shahzad Ahmad ◽  
Muntaha Talat ◽  
Shaan Bibi Jaffri ◽  
Neelofer Shaheen
Keyword(s):  
Cancer Treatment ◽  
Cancer Therapeutics ◽  
Physicochemical Characteristics ◽  
Global Scale ◽  
Current Review ◽  
Anti Cancer ◽  
Different Types ◽  
Cancerous Cells

AbstractConventional treatment modes like chemotherapy, thermal and radiations aimed at cancerous cells eradication are marked by destruction pointing the employment of nanomaterials as sustainable and auspicious materials for saving human lives. Cancer has been deemed as the second leading cause of death on a global scale. Nanomaterials employment in cancer treatment is based on the utilization of their inherent physicochemical characteristics in addition to their modification for using as nano-carriers and nano-vehicles eluted with anti-cancer drugs. Current work has reviewed the significant role of different types of nanomaterials in cancer therapeutics and diagnostics in a systematic way. Compilation of review has been done by analyzing voluminous investigations employing ERIC, MEDLINE, NHS Evidence and Web of Science databases. Search engines used were Google scholar, Jstore and PubMed. Current review is suggestive of the remarkable performance of nanomaterials making them candidates for cancer treatment for substitution of destructive treatment modes through investigation of their physicochemical characteristics, utilization outputs and long term impacts in patients.

scholarly journals Broken Worlds: Towards an Archaeology of the Shatter Zone

2021 ◽  
Author(s):  
Ben Raffield
Keyword(s):  
Eighteenth Century ◽  
Global Scale ◽  
Physical Geography ◽  
Trigger Factors ◽  
Eastern Woodlands ◽  
Term Change ◽  
Anthropological Research ◽  
Historic Change

AbstractIn recent years, archaeological studies of long-term change and transformation in the human past have often been dominated by the discussion of dichotomous processes of ‘collapse’ and ‘resilience’. These discussions are frequently framed in relatively narrow terms dictated by specialist interests that place an emphasis on the role of single ‘trigger’ factors as motors for historic change. In order to address this issue, in this article I propose that the study of the ‘shatter zone’—a term with origins in physical geography and geopolitics that has been more recently harnessed in anthropological research—has the potential to facilitate multi-scalar, interdisciplinary analyses of the ways in which major historical changes unfold across both space and time, at local, regional, and inter-regional levels. This article unpacks the concept of the shatter zone and aligns this with existing archaeological frameworks for the study of long-term adaptive change. I then situate these arguments within the context of recent studies of colonial interaction and conflict in the Eastern Woodlands of North America during the sixteenth to eighteenth century. The study demonstrates how a more regulated approach to the shatter zone has the potential to yield new insights on the ways in which populations mitigate and react to instability and change while also facilitating comparative studies of these processes on a broader, global scale.

scholarly journals Soil salinization under different climate change scenarios: A global scale analysis

2021 ◽  
Author(s):  
Nima Shokri ◽  
Amirhossein Hassani ◽  
Adisa Azapagic
Keyword(s):  
Climate Change ◽  
Water Resources ◽  
Soil Salinity ◽  
Global Scale ◽  
Soil Salinization ◽  
Water Evaporation ◽  
Climate Change Scenarios ◽  
Spatio Temporal ◽  
Salt Affected Soils

<p>Population growth and climate change is projected to increase the pressure on land and water resources, especially in arid and semi-arid regions. This pressure is expected to affect all driving mechanisms of soil salinization comprising alteration in soil hydrological balance, sea salt intrusion, wet/dry deposition of wind-born saline aerosols — leading to an increase in soil salinity. Soil salinity influences soil stability, bio-diversity, ecosystem functioning and soil water evaporation (1). It can be a long-term threat to agricultural activities and food security. To devise sustainable action plan investments and policy interventions, it is crucial to know when and where salt-affected soils occur. However, current estimates on spatio-temporal variability of salt-affected soils are majorly localized and future projections in response to climate change are rare. Using Machine Learning (ML) algorithms, we related the available measured soil salinity values (represented by electrical conductivity of the saturated paste soil extract, EC<sub>e</sub>) to some environmental information (or predictors including outputs of Global Circulation Models, soil, crop, topographic, climatic, vegetative, and landscape properties of the sampling locations) to develop a set of data-driven predictive tools to enable the spatio-temporal predictions of soil salinity. The outputs of these tools helped us to estimate the extent and severity of the soil salinity under current and future climatic patterns at different geographical levels and identify the salinization hotspots by the end of the 21<sup>st</sup> century in response to climate change. Our analysis suggests that a soil area of 11.73 Mkm<sup>2</sup> located in non-frigid zones has been salt-affected in at least three-fourths of the 1980 - 2018 period (2). At the country level, Brazil, Peru, Sudan, Colombia, and Namibia were estimated to have the highest rates of annual increase in the total area of soils with an EC<sub>e</sub> ≥ 4 dS m<sup>-1</sup>. Additionally, the results indicate that by the end of the 21<sup>st</sup> century, drylands of South America, southern and Western Australia, Mexico, southwest United States, and South Africa will be the salinization hotspots (compared to the 1961 - 1990 period). The results of this study could inform decision-making and contribute to attaining the United Nation’s Sustainable Development Goals for land and water resources management.</p><p>1. Shokri-Kuehni, S.M.S., Raaijmakers, B., Kurz, T., Or, D., Helmig, R., Shokri, N. (2020). Water Table Depth and Soil Salinization: From Pore-Scale Processes to Field-Scale Responses. Water Resour. Res., 56, e2019WR026707. https://doi.org/ 10.1029/2019WR026707</p><p>2. Hassani, A., Azapagic, A., Shokri, N. (2020). Predicting Long-term Dynamics of Soil Salinity and Sodicity on a Global Scale, Proc. Nat. Acad. Sci., 117, 52, 33017–33027. https://doi.org/10.1073/pnas.2013771117</p>

scholarly journals Dung in the dumps: what we can learn from multi-proxy studies of archaeological dung pellets

2020 ◽  
Author(s):  
Daniel Fuks ◽  
Zachary C. Dunseth
Keyword(s):  
Deposition Time ◽  
Chemical Methods ◽  
Unit Of Analysis ◽  
Plant Remains ◽  
Ecosystem Transformation ◽  
Spatio Temporal ◽  
Archaeological Sediments

AbstractA key question in archaeobotany concerns the role of herbivore dung in contributing plant remains to archaeobotanical assemblages. This issue has been discussed for at least 40 years and has motivated several archaeobotanical studies on identifying dung-derived deposition of plant remains. Meanwhile, microarchaeological methods have developed and continue to be developed for detecting dung in archaeological sediments, and multi-proxy methodologies are being used to study the botanical components of dung-associated sediments. Combining these approaches, the authors recently led a study incorporating different botanical proxies (seeds, pollen, phytoliths) with geoarchaeological sedimentary analysis to compare dung pellets and associated sediments. This approach presents a new way to gauge the contribution of dung-derived plant remains in archaeobotanical assemblages, which is further explored in this follow-up paper. The present paper further highlights how multi-proxy archaeobotanical investigation of individual dung pellets can provide information on seasonality, grazing range and herding practices. Their short production and deposition time make herbivore dung pellets time capsules of agropastoral activity, a useful spatio-temporal unit of analysis, and even a type of archaeological context in their own right. Adding different biomolecular and chemical methods to future multi-proxy archaeobotanical investigation of herbivore dung will produce invaluable high-resolution reconstructions of dung microbiomes. Ultimately, unpacking the contents of ancient dung pellets will inform on the species, physical characteristics, diet, niche, and disease agents of the ancient pellets’ producers. Expanded datasets of such dung-derived information will contribute significantly to the study of ecosystem transformation as well as the long-term development of agriculture and pastoralism.

scholarly journals Role of Ural blocking in Arctic sea ice loss and its connection with Arctic warming in winter

2020 ◽  
Author(s):  
Dong-Jae Cho ◽  
Kwang-Yul Kim
Keyword(s):  
Sea Ice ◽  
Turbulent Flux ◽  
Longwave Radiation ◽  
Arctic Sea Ice ◽  
Sea Surface ◽  
Feedback Process ◽  
Arctic Warming ◽  
Open Sea

AbstractUral blocking (UB) is suggested as one of the contributors to winter sea ice loss in the Barents–Kara Seas (BKS). This study compares UB with Arctic warming (AW) in order to delineate the role of UB on winter sea ice loss and its potential link with AW. A detailed comparison reveals that UB and AW are partly linked on sub-seasonal scales via a two-way interaction; circulation produced by AW affects UB and advection induced by UB affects temperature in AW. On the other hand, the long-term impacts of AW and UB on the sea ice concentration in the BKS are distinct. In AW, strong turbulent flux from the sea surface warms the lower troposphere, increases downward longwave radiation, and broadens the open sea surface. This feedback process explains the substantial sea ice reduction observed in the BKS in association with long-term accelerating trend. Patterns of turbulent flux, net evaporation, and net longwave radiation at surface associated with UB are of opposite signs to those associated with AW, which implies that moisture and heat flux is suppressed as warm and moist air is advected from mid-latitudes. As a result, vertical feedback process is hindered under UB. The qualitative and quantitative differences arise in terms of their impacts on sea ice concentrations in the BKS, because strong turbulent flux from the open sea surface is a main driving force in AW whereas heat and moisture advection is a main forcing in UB.

scholarly journals A hippocampal model for behavioral time acquisition and fast bidirectional replay of spatio-temporal memory sequences

2018 ◽  
Author(s):  
Marcelo Matheus Gauy ◽  
Johannes Lengler ◽  
Hafsteinn Einarsson ◽  
Florian Meier ◽  
Felix Weissenberger ◽  
...  
Keyword(s):  
Functional Role ◽  
Long Term Memory ◽  
Temporal Memory ◽  
Synfire Chains ◽  
Dendritic Spikes ◽  
Spatio Temporal ◽  
Time Acquisition ◽  
Global Inhibition

AbstractThe hippocampus is known to play a crucial role in the formation of long-term memory. For this, fast replays of previously experienced activities during sleep or after reward experiences are believed to be crucial. But how such replays are generated is still completely unclear. In this paper we propose a possible mechanism for this: we present a model that can store experienced trajectories on a behavioral timescale after a single run, and can subsequently bidirectionally replay such trajectories, thereby omitting any specifics of the previous behavior like speed, etc, but allowing repetitions of events, even with different subsequent events. Our solution builds on well-known concepts, one-shot learning and synfire chains, enhancing them by additional mechanisms using global inhibition and disinhibition. For replays our approach relies on dendritic spikes and cholinergic modulation, as supported by experimental data. We also hypothesize a functional role of disinhibition as a pacemaker during behavioral time.

scholarly journals Refugees and Recruitment: Understanding Violations Against Children in Armed Conflict With Novel Data

2019 ◽  
Vol 15 (1) ◽  
pp. 75-90
Author(s):  
Kelly E. Atkinson
Keyword(s):  
Armed Conflict ◽  
Global Scale ◽  
Annual Reports ◽  
Policy Recommendations ◽  
Data Set ◽  
Significant Challenge ◽  
International Stability ◽  
Broad Role

What makes child recruitment into armed conflict more likely? Violations against children in armed conflict pose a significant challenge to conflict resolution, long-term peacebuilding efforts, and international stability, yet little data are available on a global scale to understand the scope and causes of child recruitment into conflict. This article makes two contributions towards closing this analytical gap. First, utilising annual reports of the United Nations Secretary-General on children and armed conflict, this article codes child recruitment and other grave violations against children for 28 countries from 2006 to 2015 producing a new data set. Second, using this data set, this article examines the broad role of displacement in shaping child recruitment into armed conflict. Ultimately, this article finds that displacement within a country is positively and statistically significantly correlated with violations against children in armed conflict to include child recruitment and introduces policy recommendations for engaging this finding.

scholarly journals Transnational gentrification, tourism and the formation of ‘foreign only’ enclaves in Barcelona

Urban Studies ◽  
2020 ◽  
Vol 57 (15) ◽  
pp. 3025-3043 ◽  
Author(s):  
Agustin Cocola-Gant ◽  
Antonio Lopez-Gay
Keyword(s):  
Global Scale ◽  
Division Of Labour ◽  
Transnational Mobility ◽  
Advanced Economies ◽  
Transnational Migrants ◽  
Neighbourhood Change ◽  
The City ◽  
Depth Interviews

In a context of global-scale inequalities and increased middle-class transnational mobility, this paper explores how the arrival of Western European and North American migrants in Barcelona drives a process of gentrification that coexists and overlaps with the development of tourism in the city. Research has focused increasingly on the role of visitors and Airbnb in driving gentrification. However, our aim is to add another layer to the complexity of neighbourhood change in tourist cities by considering the role of migrants from advanced economies as gentrifiers in these neighbourhoods. We combined socio-demographic analysis with in-depth interviews and, from this, we found that: (1) lifestyle opportunities, rather than work, explain why transnational migrants are attracted to Barcelona, resulting in privileged consumers of housing that then displace long-term residents; (2) migrants have become spatially concentrated in tourist enclaves and interact predominantly with other transnational mobile populations; (3) the result is that centrally located neighbourhoods are appropriated by foreigners – both visitors and migrants – who are better positioned in the unequal division of labour, causing locals to feel increasingly excluded from the place. We illustrate that tourism and transnational gentrification spatially coexist and, accordingly, we provide an analysis that integrates both processes to understand how neighbourhood change occurs in areas impacted by tourism. By doing so, the paper offers a fresh reading of how gentrification takes place in a Southern European destination and, furthermore, it provides new insights into the conceptualisation of tourism and lifestyle migration as drivers of gentrification.

scholarly journals Clinical-morphological parallels of the PNPLA3 gene polymorphism in patients with nonalcoholic fatty liver disease

2018 ◽  
Vol 90 (2) ◽  
pp. 85-88
Author(s):  
A S Tikhomirova ◽  
V A Kislyakov ◽  
I E Baykova ◽  
I G Nikitin
Keyword(s):  
Hepatocellular Carcinoma ◽  
Liver Disease ◽  
Gene Polymorphism ◽  
Fatty Liver ◽  
Fatty Liver Disease ◽  
Global Scale ◽  
Alcoholic Fatty Liver ◽  
Nonalcoholic Fatty Liver

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease, and its detection in the general population has reached a global scale. Despite the fact that in the early stages the disease is characterized by a relatively mild period, the development during its natural course of nonalcoholic steatohepatitis, cirrhosis and hepatocellular carcinoma causes deterioration of long-term forecast. Growing evidence indicates that NAFLD is a complex, multifaceted etiology, involving many factors, including genetic. In the present review, we focused on the genetic component of NAFLD, namely, the role of the PNPLA3 gene polymorphism in the development and course of the disease, and States its progression, such as non-alcoholic steatohepatitis, liver cirrhosis and hepatocellular carcinoma.

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