scholarly journals Size and Persistence of Nitrous Oxide Hot-Spots in Grazed and Ungrazed Grassland

2015 ◽  
Vol 5 (4) ◽  
pp. 1 ◽  
Author(s):  
Paul R. Hargreaves ◽  
Robert M. Rees ◽  
Graham W. Horgan ◽  
Bruce C. Ball
Keyword(s):  
Nitrous Oxide ◽  
Soil Temperature ◽  
Hot Spots ◽  
Hot Spot ◽  
Nutrient Input ◽  
Young Stock ◽  
Spatial And Temporal Heterogeneity ◽  
The Mean ◽  
To Come ◽  
The Uk

<p class="1Body">Nitrous oxide (N<sub>2</sub>O) emissions from agriculture contributed an estimated 60% of the global total in 2005. In the UK, grassland soils account for 30% of total emissions, 22% of which are estimated to come from urine and dung patches. These patches are possible sources of ‘hot-spots’ (area <em>ca.</em> 1 m<sup>2</sup>) of N<sub>2</sub>O fluxes. Spatial and temporal heterogeneity of N<sub>2</sub>O hot-spot fluxes were investigated in three grassland fields (grazed with dairy cows (DG), grazed with young stock (YG) or cut for silage (SC)) using gas sampling chambers surrounding historic hot-spots to establish their size. Fluxes from old dung and urine patches were measured, as well as freshly applied dung and urine to simulate the creation of hot-spots. Potential chemical and physical drivers were also measured. Large spatial variability of N<sub>2</sub>O fluxes was seen in all three grassland fields. Mean N<sub>2</sub>O fluxes for the historic hot-spots in the grazed fields (DG and YG) were significantly greater than (SC). The mean N<sub>2</sub>O fluxes in DG and YG (117.9 and 243.5 ng N m<sup>-2</sup> s<sup>-1</sup>) were 15 to 30% greater than for SC. Soil temperature (15 - 20 °C) was the most significant driver of N<sub>2</sub>O production with a 1°C rise in soil temperature increasing emissions under DG and YG. N<sub>2</sub>O fluxes were enhanced by the fresh dung but not by urine. However, in the urine treatment, the nutrient input increased the microbial respiration response for the CO<sub>2</sub> flux. Hot-spot N<sub>2</sub>O emissions from old urine and dung patches were persistent several months after application.</p>

scholarly journals Nitrous oxide emissions from a beech forest floor measured by eddy covariance and soil enclosure techniques

2005 ◽  
Vol 2 (3) ◽  
pp. 581-607
Author(s):  
M. Pihlatie ◽  
J. Rinne ◽  
P. Ambus ◽  
K. Pilegaard ◽  
J. R. Dorsey ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Spatial Variability ◽  
Eddy Covariance ◽  
Hot Spot ◽  
Beech Forest ◽  
Nitrous Oxide Emissions ◽  
N2o Emissions ◽  
The Mean ◽  
N2o Fluxes ◽  
Trunk Space

Abstract. Spring time soil nitrous oxide (N2O) fluxes were measured in an old beech (Fagus sylvatica L.) forest with eddy covariance (EC) and chamber techniques. The aim was to compare the two techniques and to test whether EC can be used in the trunk-space of the forest to measure N2O. Mean N2O fluxes over the five week measurement period were 5, 10 and 16 μg N m-2h-1 from EC, automatic chamber and manual chambers, respectively. When data from one hot spot chamber was excluded the mean N2O flux of 8 μg N m-2h-1 from the soil chambers nearly equaled to the mean flux of 7 μg N m-2h-1 measured with EC from the direction were soil chambers located. Spatial variability in the N2O emissions was high in soil chamber measurements, while the EC integrated over this spatial variability and suggested that N2O emissions were uniform within the footprint area. The highest emissions measured with the EC occurred during the first week of May when the trees were leafing and when soil moisture content was at its highest. To our knowledge, this is the first study to demonstrate that the EC technique can be used to measure N2O fluxes in the trunk-space of a forest. If chamber techniques are used to estimate ecosystem level N2O emissions from forest soils, placing of the chambers should be considered carefully to cover the heterogeneity in the soil N2O emissions.

Tuberculosis trends in a hot-spot region in Paris, France

2020 ◽  
Vol 24 (4) ◽  
pp. 428-435
Author(s):  
C. Pierre-Audigier ◽  
C. Talla ◽  
A-K. Alame-Emane ◽  
B. Audigier ◽  
N. Grall ◽  
...  
Keyword(s):  
Hot Spots ◽  
Hot Spot ◽  
Demographic Data ◽  
Control Measures ◽  
Foreign Born ◽  
Time Period ◽  
Claude Bernard ◽  
Resistant Strains ◽  
The Mean ◽  
Drug Resistant Strains

SETTING: Tuberculosis (TB) incidence is declining overall in France, but not in Paris where some areas remain relative hot spots for TB.OBJECTIVES: To obtain a better knowledge of local TB epidemiology in order to facilitate control measures.DESIGN: Analysis of demographic data of TB patients diagnosed at the Bichat-Claude Bernard Hospital from 2007 to 2016, with spoligotyping of Mycobacterium tuberculosis complex isolates.RESULTS: During the study period, 1096 TB patients were analysed. The incidence of TB diagnosis was stable, averaging 115 patients per year, predominantly males (71%), foreign-born (81%), with pulmonary TB (77%) and negative HIV serology (88%). The mean age of foreign-born TB patients decreased over the study period, most significantly in recent arrivals in France, whose average age decreased by two years (P = 0.001). The time period between arrival in France and being diagnosed with active TB decreased annually significantly by 0.75 years (P = 0.02). The proportion of L4.6.2/Cameroon and L2/Beijing sub-lineages increased annually by 0.7% (P < 0.05). Multi-drug resistant strains, representing 4% of all strains, increased annually by 0.75% (P = 0.03)CONCLUSION: The number of TB patients remained high in northern Paris and the surrounding suburbs, suggesting the need for increased control measures.

Spatial Hotspot Analysis of Bucharest’s Urban Heat Island (UHI) Using Modis Data

2018 ◽  
Vol 18 (1) ◽  
pp. 14-22 ◽  
Author(s):  
Georgiana Grigoraș ◽  
Bogdan Urițescu
Keyword(s):  
Surface Temperature ◽  
Air Temperature ◽  
Land Surface Temperature ◽  
Hot Spots ◽  
Land Surface ◽  
Hot Spot ◽  
Monitoring Network ◽  
Residential Areas ◽  
Hotspot Analysis ◽  
The City

Abstract The aim of the study is to find the relationship between the land surface temperature and air temperature and to determine the hot spots in the urban area of Bucharest, the capital of Romania. The analysis was based on images from both moderate-resolution imaging spectroradiometer (MODIS), located on both Terra and Aqua platforms, as well as on data recorded by the four automatic weather stations existing in the endowment of The National Air Quality Monitoring Network, from the summer of 2017. Correlation coefficients between land surface temperature and air temperature were higher at night (0.8-0.87) and slightly lower during the day (0.71-0.77). After the validation of satellite data with in-situ temperature measurements, the hot spots in the metropolitan area of Bucharest were identified using Getis-Ord spatial statistics analysis. It has been achieved that the “very hot” areas are grouped in the center of the city and along the main traffic streets and dense residential areas. During the day the "very hot spots” represent 33.2% of the city's surface, and during the night 31.6%. The area where the mentioned spots persist, falls into the "very hot spot" category both day and night, it represents 27.1% of the city’s surface and it is mainly represented by the city center.

The family Orthotrichaceae (Bryophyta) in flora of Russia: results of revision and biogeographical review

2018 ◽  
Vol 52 (2) ◽  
pp. 519-534 ◽  
Author(s):  
V. E. Fedosov
Keyword(s):  
Hot Spots ◽  
Latitudinal Gradient ◽  
Hot Spot ◽  
Spatial Differentiation ◽  
Taxonomic Composition ◽  
Undescribed Species ◽  
Longitudinal Gradient ◽  
Biogeographic Pattern ◽  
The Family ◽  
North Pacific Region

Recent studies on Orthotrichoid mosses in Russia are summarized genus by genus. Orthotrichum furcatum Otnyukova is synonymized with Nyholmiella obtusifolia. Orthotrichum vittii is excluded from the Russian moss flora. Description of O. dagestanicum is amended. Fifty four currently recognized species from 9 genera of the Orthotrichaceae are presently known to occur in Russia; list of species with common synonyms and brief review of distribution in Russia is presented. Numerous problematic specimens with unresolved taxonomy were omitted for future. Revealed taxonomical inconsistencies in the genera Zygodon, Ulota, Lewinskya, Nyholmiella, Orthotrichum are briefly discussed. Main regularities of spatial differentiation of the family Orthotrichaceae in Russia are considered. Recently presented novelties contribute to the certain biogeographic pattern, indicating three different centers of diversity of the family, changing along longitudinal gradient. Unlike European one, continental Asian diversity of Orthotrichaceae is still poorly known, the Siberian specimens which were previously referred to European species in most cases were found to represent other, poorly known or undescribed species. North Pacific Region houses peculiar and poorly understood hot spot of diversity of Orthotrichoid mosses. Thus, these hot spots are obligatory to be sampled in course of revisions of particular groups, since they likely comprise under-recorded cryptic- or semi-cryptic species. Latitudinal gradient also contributes to the spatial differentiation of the revealed taxonomic composition of Orthotrichaceae.

Tele-ophthalmology for screening for eye diseases in older patients with cognitive complaints

2020 ◽  
pp. 1357633X1989388
Author(s):  
Anne-Sophie Boureau ◽  
Helene Masse ◽  
Guillaume Chapelet ◽  
Laure de Decker ◽  
Pascal Chevalet ◽  
...  
Keyword(s):  
Cognitive Assessment ◽  
Older Patients ◽  
Screening Method ◽  
Poor Quality ◽  
Eye Diseases ◽  
Ophthalmological Examination ◽  
Cognitive Complaints ◽  
The Mean ◽  
To Come ◽  
Retinal Photographs

Introduction Population-based studies show a significant increase in the prevalence of visual impairment in older patients. However, older patients and patients with lower Mini-Mental State Examination (MMSE) scores have few ophthalmological assessments. The main objective of our study was to evaluate the feasibility of tele-ophthalmological screening for ophthalmological diseases in older patients referred for cognitive assessment. Methods This monocentric prospective study included patients referred to a memory clinic for cognitive assessment. All patients underwent a geriatric assessment comprising a cognitive assessment associated with tele-ophthalmological screening undertaken by an orthoptist, including undilated retinal photography. The retinal photographs were subsequently sent to an ophthalmologist. We identified patients who were not eligible for ophthalmological assessment, for patients that had to come back due to poor-quality retinal photographs and finally for detected eye diseases. The association between the geriatric variable and newly detected eye diseases was analysed in univariable and multivariable analyses. Results The mean age of the 298 patients included was 83.5 years  ± 5.65; 29.5% were male. The mean MMSE score was 20.8 ± 5.2; 66.3% of patients had a diagnosis of dementia. Eighteen patients (6.0%) were not eligible for ophthalmological examination and 13 patients (4.6%) were asked to come back owing to poor-quality retinal photographs. Forty-one patients (13.7%) had a newly detected eye disease. In multivariable analysis, patients with a lower MMSE had significantly more newly identified eye diseases. Discussion The tele-ophthalmological screening method identified unknown ophthalmological diseases requiring specialised management in this older population with cognitive complaints.

scholarly journals Family Practices and Temporality at Breakfast: Hot Spots, Convenience and Care

Sociology ◽  
2021 ◽  
pp. 003803852110155
Author(s):  
Daniela Pirani ◽  
Vicki Harman ◽  
Benedetta Cappellini
Keyword(s):  
Hot Spots ◽  
Hot Spot ◽  
Family Meals ◽  
Personal Integrity ◽  
Structured Interviews ◽  
Time Saving ◽  
Family Time ◽  
Dominant Feature ◽  
Family Practices ◽  
Cold Spots

Drawing on 34 semi-structured interviews, this study investigates the temporality of family practices taking place in the hot spot. It does so by looking at how breakfast is inserted in the economy of family time in Italy. Our data show that breakfast, contrary to other meals, allows the adoption of more individualised and asynchronous practices, hinged on the consumption of convenience products. These time-saving strategies are normalised as part of doing family. Although the existing literature suggests that convenience and care are in opposition, and consumers of convenience products can experience anxiety and a lack of personal integrity, such features were not a dominant feature of our participants’ accounts. These findings suggest that the dichotomies of hot/cold spots and care/convenience are not always experienced in opposition when embedded within family practices. Hence, this study furthers understandings of family meals, temporality and the distinction between hot and cold spots.

Investigation of On-Chip Hot Spot Cooling Using Microchannel Heat Sink

2013 ◽  
Vol 455 ◽  
pp. 466-469
Author(s):  
Yun Chuan Wu ◽  
Shang Long Xu ◽  
Chao Wang
Keyword(s):  
Heat Flux ◽  
Heat Sink ◽  
Hot Spots ◽  
Hot Spot ◽  
High Heat ◽  
High Heat Flux ◽  
Microchannel Heat Sink ◽  
Three Dimensional Model ◽  
Spot Cooling ◽  
On Chip

With the increase of performance demands, the nonuniformity of on-chip power dissipation becomes greater, causing localized high heat flux hot spots that can degrade the processor performance and reliability. In this paper, a three-dimensional model of the copper microchannel heat sink, with hot spot heating and background heating on the back, was developed and used for numerical simulation to predict the hot spot cooling performance. The hot spot is cooled by localized cross channels. The pressure drop, thermal resistance and effects of hot spot heat flux and fluid flow velocity on the cooling of on-chip hot spots, are investigated in detail.

Tissue Ki67 proliferative index expression and pathological changes in hemodialysis arteriovenous fistulae: Preliminary single-center results

2021 ◽  
pp. 112972982110154
Author(s):  
Raffaella Mauro ◽  
Cristina Rocchi ◽  
Francesco Vasuri ◽  
Alessia Pini ◽  
Anna Laura Croci Chiocchini ◽  
...  
Keyword(s):  
Morphological Changes ◽  
Hot Spot ◽  
Wall Thickening ◽  
Proliferating Cells ◽  
Ki 67 ◽  
Group A ◽  
The Mean ◽  
Set Up ◽  
Group B

Background: Arteriovenous fistula (AVF) for hemodialysis integrates outward remodeling with vessel wall thickening in response to drastic hemodynamic changes. Aim of this study is to determine the role of Ki67, a well-established proliferative marker, related to AVF, and its relationship with time-dependent histological morphologic changes. Materials and methods: All patients were enrolled in 1 year and stratified in two groups: (A) pre-dialysis patients submitted to first AVF and (B) patients submitted to revision of AVF. Morphological changes: neo-angiogenesis (NAG), myointimal thickening (MIT), inflammatory infiltrate (IT), and aneurysmatic fistula degeneration (AD). The time of AVF creation was recorded. A biopsy of native vein in Group A and of arterialized vein in Group B was submitted to histological and immunohistochemical (IHC) analysis. IHC for Ki67 was automatically performed in all specimens. Ki67 immunoreactivity was assessed as the mean number of positive cells on several high-power fields, counted in the hot spots. Results: A total of 138 patients were enrolled, 69 (50.0%) Group A and 69 (50.0%) Group B. No NAG or MIT were found in Group A. Seven (10.1%) Group A veins showed a mild MIT. Analyzing the Group B, a moderate-to-severe MIT was present in 35 (50.7%), IT in 19 (27.5%), NAG in 37 (53.6%); AD was present in 10 (14.5%). All AVF of Group B with the exception of one (1.4%) showed a positivity for Ki67, with a mean of 12.31 ± 13.79 positive cells/hot spot (range 0–65). Ki67-immunoreactive cells had a subendothelial localization in 23 (33.3%) cases, a myointimal localization in SMC in 35 (50.7%) cases. The number of positive cells was significantly correlated with subendothelial localization of Ki67 ( p = 0.001) and with NA ( p = 0.001). Conclusions: Native veins do not contain cycling cells. In contrast, vascular cell proliferation starts immediately after AVF creation and persists independently of the time the fistula is set up. The amount of proliferating cells is significantly associated with MIT and subendothelial localization of Ki67-immunoreactive cells, thus suggesting a role of Ki-67 index in predicting AVF failure.

scholarly journals Nitrous Oxide Emissions in Pineapple Cultivation on a Tropical Peat Soil

2021 ◽  
Vol 13 (9) ◽  
pp. 4928
Author(s):  
Alicia Vanessa Jeffary ◽  
Osumanu Haruna Ahmed ◽  
Roland Kueh Jui Heng ◽  
Liza Nuriati Lim Kim Choo ◽  
Latifah Omar ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Soil Temperature ◽  
Peat Soil ◽  
Farming Systems ◽  
N2o Emission ◽  
Nitrous Oxide Emissions ◽  
Natural State ◽  
N2o Emissions ◽  
Wet Season ◽  
Peat Soils

Farming systems on peat soils are novel, considering the complexities of these organic soil. Since peat soils effectively capture greenhouse gases in their natural state, cultivating peat soils with annual or perennial crops such as pineapples necessitates the monitoring of nitrous oxide (N2O) emissions, especially from cultivated peat lands, due to a lack of data on N2O emissions. An on-farm experiment was carried out to determine the movement of N2O in pineapple production on peat soil. Additionally, the experiment was carried out to determine if the peat soil temperature and the N2O emissions were related. The chamber method was used to capture the N2O fluxes daily (for dry and wet seasons) after which gas chromatography was used to determine N2O followed by expressing the emission of this gas in t ha−1 yr−1. The movement of N2O horizontally (832 t N2O ha−1 yr−1) during the dry period was higher than in the wet period (599 t N2O ha−1 yr−1) because of C and N substrate in the peat soil, in addition to the fertilizer used in fertilizing the pineapple plants. The vertical movement of N2O (44 t N2O ha−1 yr−1) was higher in the dry season relative to N2O emission (38 t N2O ha−1 yr−1) during the wet season because of nitrification and denitrification of N fertilizer. The peat soil temperature did not affect the direction (horizontal and vertical) of the N2O emission, suggesting that these factors are not related. Therefore, it can be concluded that N2O movement in peat soils under pineapple cultivation on peat lands occurs horizontally and vertically, regardless of season, and there is a need to ensure minimum tilling of the cultivated peat soils to prevent them from being an N2O source instead of an N2O sink.

scholarly journals Cambial Activity and Phenology in Three Understory Species along an Altitude Gradient in Mexico

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 506
Author(s):  
Mayte S. Jiménez-Noriega ◽  
Lauro López-Mata ◽  
Teresa Terrazas
Keyword(s):  
Soil Temperature ◽  
Sierra Nevada ◽  
Cambial Activity ◽  
Life Forms ◽  
Dry Season ◽  
Vascular Cambium ◽  
Phenological Stages ◽  
Altitude Gradient ◽  
The Mean ◽  
Trees And Shrubs

The aims of this study were to evaluate the cambial activity and phenology of three species with different life forms (Alchemilla procumbens, Acaena elongata and Ribes ciliatum) along an altitudinal gradient and to establish which environmental variables (light, soil humidity and temperature) had the greatest influence on cambial activity and phenological stages. Over two years, data on phenology, growth and cambium were gathered every four weeks in three to six sites per species in Sierra Nevada, Mexico. The results showed that Ribes is the only species that terminates cambial activity with leaves senescence and is influenced by the minimum soil temperature. The light environment influenced the vegetative stages in Alchemilla (cryptophyte), while in Acaena (hemicryptophyte), the mean soil temperature explained the findings related to leaf area during the dry season and growth along the gradient. In the three species, the reproductive phase dominated for a longer period at higher elevations, especially in Alchemilla. Only Ribes, the phanerophyte, showed a similar cambial activity to other trees and shrubs. Although cambium reactivates during the dry season, no xylogenesis occurs. The three species varied during the time in which vascular cambium was active, and this was dependent on the altitude. Specifically, the variation was more rhythmic in Ribes and switched on and off in Alchemilla. It is likely that, depending on the life form, vascular cambium may be more or less susceptible to one or more climate factors.

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