53 research outputs found
Big Powers, Small Islands, Real Displaced People. Response to Gettel, Eliza. Recognizing the Delians Displaced after 167/6 BCE. Humanities 2018, 7, 91
No full textEliza Gettel’s paper on the displacement of the Delians in the second century BCE does an excellent job of examining an ancient case study of displacement through the lens of contemporary conceptions of displacement and asylum. In this paper, I try, as a modern historian of asylum, to reflect on the applicability of modern classifications to a case study over 2000 years old. First, I discuss the compatibility of the ancient with the modern. Subsequently, I engage much more deliberately with the arguments Gettel presents in her paper. Finally, I introduce a contemporary case study involving the displacement of people from the Chagos Islands in the Indian Ocean that I argue shares some similarities with that of the Delians, with both cases highlighting the often-neglected agency of the displaced
Recognizing the Delians Displaced after 167/6 BCE
No full textIn 167/6 BCE, the Roman senate granted a request from Athens to control the island of Delos. Subsequently, the Delians inhabiting the island were mandated to leave and an Athenian community was installed. Polybius, who records these events, tells us that the Delians left and resettled in Achaea in the Peloponnese. Scholars have tended to focus on Rome’s motivations for siding with the Athenians rather than on what happened to the Delians. Furthermore, translations have tended to use the broad terminology of ‘migration’ to describe the Delians’ movement. Comparatively, this contribution suggests that modern categories connected to ‘displacement’ can help us recover aspects of the Delians’ experience. Particularly, a shift to the vocabulary of ‘displacement’ highlights the creative agency of the Delians in holding the Athenians accountable for their expulsion and in seeking recognition from Rome of their integration into the Achaean state. The application of these modern categories necessitates reflection on differences in the political, institutional landscapes that have shaped the experience of displacement in the ancient Hellenistic and modern contexts, as well as on variations in experience amongst the Delians. Ultimately, recognizing what these individuals experienced within the evolving third-party arbitration system of the ancient world leads us to think about the indirect violence of expanding political institutions in ‘globalising’ worlds, both ancient and modern
Dispersible exfoliated zeolite nanosheets and their application as a selective membrane
No full textThin zeolite films are attractive for a wide range of applications, including molecular sieve membranes, catalytic membrane reactors, permeation barriers, and low-dielectric-constant materials. Synthesis of thin zeolite films using high-aspect-ratio zeolite nanosheets is desirable because of the packing and processing advantages of the nanosheets over isotropic zeolite nanoparticles. Attempts to obtain a dispersed suspension of zeolite nanosheets via exfoliation of their lamellar precursors have been hampered because of their structure deterioration and morphological damage (fragmentation, curling, and aggregation). We demonstrated the synthesis and structure determination of highly crystalline nanosheets of zeolite frameworks MWW and MFI. The purity and morphological integrity of these nanosheets allow them to pack well on porous supports, facilitating the fabrication of molecular sieve membranes
Classification of Geomorphic Units and Their Relevance for Nutrient Retention or Export of a Large Lowland Padma River, Bangladesh: A NDVI Based Approach
No full textGeomorphic classification of large rivers identifies morphological patterns, as a foundation for estimating biogeochemical and ecological processes. In order to support the modelling of in-channel nutrient retention or export, the classification of geomorphic units (GUs) was done in the Padma River, Bangladesh, a large and geomorphically-complex lowland river. GUs were classified using the normalized difference vegetation index (NDVI) four times over a year, so as to cover the seasonal variation of water flows. GUs were categorized as primary and secondary channels (C & S); longitudinal bar (L); transverse bar (T); side bar (SB); unvegetated bank (EK); dry channel (ED); island (VI); and water depression (WD). All types of GUs were observed over the four distinct annual seasons, except ED, which was absent during the high flow, monsoon season. Seasonal variation of the surface area of GUs and discharge showed an inverse relation between discharge and exposed surface areas of VI, L, T, and SB. Nutrients mainly enter the river system through water and sediments, and during monsoon, the maximum portion of emergent GUs were submerged. Based on the assumption that nutrient retention is enhanced in the seasonally inundated portions of GUs, nutrient retention-/export-relevant geomorphic units (NREGUs) were identified. Seasonal variation in the area of NREGUs was similar to that of GUs. The mean NDVI values of the main identified NREGUs were different. The variation of NDVI values among seasons in these NREGUs resulted from changes of vegetation cover and type. The variation also occurred due to alteration of the surface area of GUs in different seasons. The changes of vegetation cover indicated by NDVI values across seasons are likely important drivers for biogeochemical and ecological processes.Water Resource
Controls of Benthic Nitrogen Fixation and Primary Production from Nutrient Enrichment of Oligotrophic, Arctic Lakes
No full text© The Author(s), 2013. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Ecosystems 16 (2013): 1550-1564, doi:10.1007/s10021-013-9701-0.We examined controls of benthic dinitrogen (N2) fixation and primary production in oligotrophic lakes in Arctic Alaska, Toolik Field Station (Arctic Long-Term Ecological Research Site). Primary production in many oligotrophic lakes is limited by nitrogen (N), and benthic processes are important for whole-lake function. Oligotrophic lakes are increasingly susceptible to low-level, non-point source nutrient inputs, yet the effects on benthic processes are not well understood. This study examines the results from a whole-lake fertilization experiment in which N and P were added at a relatively low level (4 times natural loading) in Redfield ratio to a shallow (3 m) and a deep (20 m) oligotrophic lake. The two lakes showed similar responses to fertilization: benthic primary production and respiration (each 50–150 mg C m−2 day−1) remained the same, and benthic N2 fixation declined by a factor of three- to fourfold by the second year of treatment (from ~0.35 to 0.1 mg N m−2 day−1). This showed that the response of benthic N2 fixation was de-coupled from the nutrient limitation status of benthic primary producers and raised questions about the mechanisms, which were examined in separate laboratory experiments. Bioassay experiments in intact cores also showed no response of benthic primary production to added N and P, but contrasted with the whole-lake experiment in that N2 fixation did not respond to added N, either alone or in conjunction with P. This inconsistency was likely a result of nitrogenase activity of existing N2 fixers during the relative short duration (9 days) of the bioassay experiment. N2 fixation showed a positive saturating response when light was increased in the laboratory, but was not statistically related to ambient light level in the field, leading us to conclude that light limitation of the benthos from increasing water-column production was not important. Thus, increased N availability in the sediments through direct uptake likely caused a reduction in N2 fixation. These results show the capacity of the benthos in oligotrophic systems to buffer the whole-system response to nutrient addition by the apparent ability for significant nutrient uptake and the rapid decline in N2 fixation in response to added nutrients. Reduced benthic N2 fixation may be an early indicator of a eutrophication response of lakes which precedes the transition from benthic to water-column-dominated systems.This project was supported by
NSF-OPP 9732281, NSF-DEB 9810222, NSF-DEB
0423385, and by a Doctoral Dissertation Improvement
Grant NSF-DEB 0206173. Additional funding
was provided by the Small Grants Program through
the NSF-IGERT Program in Biogeochemistry and
Environmental Change at Cornell University
The potential importance of soil denitrification as a major N loss pathway in intensive greenhouse vegetable production systems
No full textBackground
About 30 % of vegetables in China are produced in intensively managed greenhouses comprising flood irrigation and extreme rates of nitrogen fertilizers. Little is known about denitrification N losses.
Methods
Soil denitrification rates were measured by the acetylene inhibition technique applied to anaerobically incubated soil samples. Four different greenhouse management systems were differentiated: Conventional flood irrigation and over-fertilization (CIF, 800 kg N ha−1, 460 mm); CIF plus straw incorporation (CIF+S, 889 kg N ha−1, 460 mm); Drip fertigation with reduced fertilizer application rates (DIF, 314 kg N ha−1, 190 mm); DIF plus straw incorporation (DIF+S, 403 kg N ha−1, 190 mm). Soil denitrification was measured on nine sampling dates during the growing season (Feb 2019-May 2019) for the top-/ subsoil (0 – 20/ 20- 40 cm) and on three sampling dates for deep soils (40-60/ 80-100 cm). Data was used to constrain N-input-output balances of the different vegetable production systems.
Results
Rates of denitrification were at least one magnitude higher in topsoil than in sub- and deep soils. Total seasonal denitrification N losses for the 0 – 40 cm soil layer ranged from 76 (DIF) to 422 kg N ha−1 (CIF+S). Straw addition stimulated soil denitrification in top- and subsoil, but not in deep soil layers. Integrating our denitrification data (0-100 cm) with additional data on N leaching, N2O emissions, plant N uptake, and NH3 volatilization showed, that on average 50 % of added N fertilizers are lost due to denitrification.
Conclusions
Denitrification is likely the dominant environmental N loss pathway in greenhouse vegetable production systems. Reducing irrigation and fertilizer application rates while incorporating straw in soils allows the reduction of accumulated nitrate
The potential importance of soil denitrification as a major N loss pathway in intensive greenhouse vegetable production systems
No full textBackground
About 30 % of vegetables in China are produced in intensively managed greenhouses comprising flood irrigation and extreme rates of nitrogen fertilizers. Little is known about denitrification N losses.
Methods
Soil denitrification rates were measured by the acetylene inhibition technique applied to anaerobically incubated soil samples. Four different greenhouse management systems were differentiated: Conventional flood irrigation and over-fertilization (CIF, 800 kg N ha, 460 mm); CIF plus straw incorporation (CIF+S, 889 kg N ha, 460 mm); Drip fertigation with reduced fertilizer application rates (DIF, 314 kg N ha, 190 mm); DIF plus straw incorporation (DIF+S, 403 kg N ha, 190 mm). Soil denitrification was measured on nine sampling dates during the growing season (Feb 2019-May 2019) for the top-/ subsoil (0 – 20/ 20- 40 cm) and on three sampling dates for deep soils (40-60/ 80-100 cm). Data was used to constrain N-input-output balances of the different vegetable production systems.
Results
Rates of denitrification were at least one magnitude higher in topsoil than in sub- and deep soils. Total seasonal denitrification N losses for the 0 – 40 cm soil layer ranged from 76 (DIF) to 422 kg N ha (CIF+S). Straw addition stimulated soil denitrification in top- and subsoil, but not in deep soil layers. Integrating our denitrification data (0-100 cm) with additional data on N leaching, N2O emissions, plant N uptake, and NH3 volatilization showed, that on average 50 % of added N fertilizers are lost due to denitrification.
Conclusions
Denitrification is likely the dominant environmental N loss pathway in greenhouse vegetable production systems. Reducing irrigation and fertilizer application rates while incorporating straw in soils allows the reduction of accumulated nitrate
(542) Implementing nurse-delivered massage to promote comfort among hospitalized inpatients
No full textPublic Land Use Constraints: Lot and House Configuration
No full textThe public sector constrains the size and shape of lots and buildings via zoning ordinances and subdivision regulations. Zoning ordinances utilize setback requirements, open space ratios, minimum lot area and floor-to-area ratios. Subdivision regulations utilize street and sidewalk spacing requirements. This article provides a framework in which one can analyze the precise impact of these control devices. The choice of developers who face these controls is discussed in terms of a rule of thumb and in terms of a model of profit maximization.
Unaccounted CO<sub>2</sub> leaks downstream of a large tropical hydroelectric reservoir
No full textRecent studies show that tropical hydroelectric reservoirs may be responsible for substantial greenhouse gas emissions to the atmosphere, yet emissions from the surface of released water downstream of the dam are poorly characterized if not neglected entirely from most assessments. We found that carbon dioxide (CO2) emission downstream of Kariba Dam (southern Africa) varied widely over different timescales and that accounting for downstream emissions and their fluctuations is critically important to the reservoir carbon budget. Seasonal variation was driven by reservoir stratification and the accumulation of CO2 in hypolimnetic waters, while subdaily variation was driven by hydropeaking events caused by dam operation in response to daily electricity demand. This “carbopeaking” resulted in hourly variations of CO2 emission up to 200% during stratification. Failing to account for seasonal or subdaily variations in downstream carbon emissions could lead to errors of up to 90% when estimating the reservoir’s annual emissions. These results demonstrate the critical need to include both limnological seasonality and dam operation at subdaily time steps in the assessment of carbon budgeting of reservoirs and carbon cycling along the aquatic continuum.</p
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