scholarly journals Plant–herbivore–decomposer stoichiometric mismatches and nutrient cycling in ecosystems

2013 ◽  
Vol 280 (1754) ◽  
pp. 20122453 ◽  
Author(s):  
Mehdi Cherif ◽  
Michel Loreau
Keyword(s):  
Nutrient Availability ◽  
Conceptual Models ◽  
Nutrient Content ◽  
Major Influence ◽  
Plant Nutrient ◽  
Nutrient Contents ◽  
Nutrient Excretion ◽  
Plant Herbivore ◽  
The Impact ◽  
The Relationship

Plant stoichiometry is thought to have a major influence on how herbivores affect nutrient availability in ecosystems. Most conceptual models predict that plants with high nutrient contents increase nutrient excretion by herbivores, in turn raising nutrient availability. To test this hypothesis, we built a stoichiometrically explicit model that includes a simple but thorough description of the processes of herbivory and decomposition. Our results challenge traditional views of herbivore impacts on nutrient availability in many ways. They show that the relationship between plant nutrient content and the impact of herbivores predicted by conceptual models holds only at high plant nutrient contents. At low plant nutrient contents, the impact of herbivores is mediated by the mineralization/immobilization of nutrients by decomposers and by the type of resource limiting the growth of decomposers. Both parameters are functions of the mismatch between plant and decomposer stoichiometries. Our work provides new predictions about the impacts of herbivores on ecosystem fertility that depend on critical interactions between plant, herbivore and decomposer stoichiometries in ecosystems.

scholarly journals Seasonal variation in AMF colonisation, soil and plant nutrient content in gypsum specialist and generalist species growing in P-poor soils

2021 ◽  
Author(s):  
Andreu Cera ◽  
Estephania Duplat ◽  
Gabriel Montserrat-Martí ◽  
Antonio Gómez-Bolea ◽  
Susana Rodríguez-Echeverría ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Nutrient Availability ◽  
Soil Nutrient ◽  
Nutrient Status ◽  
Nutrient Content ◽  
P Availability ◽  
Plant Nutrient ◽  
Rhizospheric Soil ◽  
Soil Nutrient Availability ◽  
Generalist Species

Abstract Aims Gypsum soils are P-limited atypical soils that harbour a rich endemic flora. These singular soils are usually found in drylands, where plant activity and soil nutrient availability are seasonal. No previous studies have analysed the seasonality of P nutrition and its interaction with the arbuscular mycorrhiza fungi (AMF) colonisation in gypsum plants. Our aim was to evaluate the seasonal changes in plant nutrient status, AMF colonisation and rhizospheric soil nutrient availability in gypsum specialist and generalist species. Methods We evaluated seasonal variation in the proportion of root length colonised by AMF structures (hyphae, vesicules and arbuscules), plant nutrient status (leaf C, N and P and fine root C and N) and rhizospheric soil content (P, organic matter, nitrate and ammonium) of three gypsum specialists and two generalists throughout a year. Results All species showed arbuscules within roots, including species of Caryophyllaceae and Brassicaceae. Root colonisation by arbuscules (AC) was higher in spring than in other seasons, when plants showed high leaf P-requirements. Higher AC was decoupled from inorganic N and P availability in rhizospheric soil, and foliar nutrient content. Generalists showed higher AC than specialists, but only in spring. Conclusions Seasonality was found in AMF colonisation, rhizospheric soil content and plant nutrient status. The mutualism between plants and AMF was highest in spring, when P-requirements are higher for plants, especially in generalists. However, AMF decoupled from plant demands in autumn, when nutrient availability increases in rhizospheric soil.

scholarly journals Effect of magnesium fertilization on yield and nutrient status of rice in kole lands

2021 ◽  
Vol 58 (4) ◽  
pp. 525-529
Author(s):  
Latha A ◽  
Chijina K ◽  
Asha V Pillai
Keyword(s):  
Field Experiments ◽  
Block Design ◽  
Soil Nutrient ◽  
Nutrient Status ◽  
Nutrient Content ◽  
Plant Nutrient ◽  
Yield Attributes ◽  
Nutrient Contents ◽  
Pooled Data ◽  
Randomized Block Design

The field experiments were conducted in farmer's field at five locations each of kole lands to study the effect of Magnesium (Mg) on yield and soil and plant nutrient status of rice during 2012-2013 and 2013-2014. The experiment was laid out in randomized block design with three replications. The treatments comprised of different levels of Mg viz; 40, 60, 80, 100, and 120 kg Magnesium sulphate(MgSO4)/ha along with control. Observations on growth characters yield attributes, yield and soil and plant nutrient status were recorded. The results revealed that application of 100 kg MgSO4 / ha recorded the maximum number of panicles/m2 (419.13), number of grains/panicle (109.36), thousand grain weight (28.78 g), grain (9.27 t/ha) and straw yield (9.04 t/ha) of rice. The results of pooled data on plant and soil nutrient status revealed that application of magnesium had a positive effect on nutrient content and availability of nutrients in soil. A significant positive correlation was also noticed between Mg application, yield attributes, yield and nutrient contents. The study concluded that application of 100 kg MgSO4 / ha was found to be optimum for correcting the deficiency in Mg deficient areas of kole lands under below sea level farming.

scholarly journals Growth Performance and Nutrient Composition of Mustard Green (Brassica juncea) cultured in Aquaponics Systems and Hydroponic System

2021 ◽  
Vol 10 (3) ◽  
pp. 373
Author(s):  
Prayogo Prayogo ◽  
Agustono Agustono ◽  
Boedi Setya Rahardja ◽  
Muhamad Amin
Keyword(s):  
Brassica Juncea ◽  
Nutrient Availability ◽  
Crude Protein ◽  
Nutrient Content ◽  
Inorganic Fertilizer ◽  
Nitrate Content ◽  
Hydroponic System ◽  
Nutrient Contents ◽  
Mustard Green ◽  
Aquaculture Waste

Aquaculture waste is rich in various nutrient contents from uneaten feed, faeces or urine including nitrogen in terms of total ammonium nitrogen (TAN) and nitrite. With the help of nitrifying bacteria, the nitrogen wastes can be converted into nitrate which is one of the main components of commercial fertilizer in agriculture. This study aimed at comparing the growth and nutrient contents (crude protein, crude fat, energy, and antioxidant) of mustard Green (Brassica juncea) cultured in different culture media (aquaculture waste which is generally known as the aquaponics system vs hydroponic system which used commercial inorganic fertilizer). The aquaponics system was prepared by previously growing Nile tilapia fingerling, Oreochromis niloticus, for ~2 weeks to reach nitrate concentration on the effluent water ~30mg/L. Mustard Green was cultured in the system for 30 days. Nutrient availability in both systems was also monitored by measuring nitrate content and total dissolved solids. The results showed that the growth, nutrient content including crude protein, crude fat, total energy, and antioxidant content of the vegetable were not significantly different between the system, p>0.05. Nutrient availability especially in terms of nitrate was also not significantly different between the culture system. These results suggest that the aquaponics system could be used to produce vegetables with the same growth and nutrient content as a vegetable grown in the aquaponics system. Furthermore, aquaculture waste can be used to replace inorganic fertilizer to grow vegetables which later contribute to the reduction of total production cost.

Accent Policy and Accent Modification Enterprises as Potential Indicators of Intercultural Power Relations: A Call for an Updated Research Agenda

2013 ◽  
Vol 3 (1) ◽  
pp. 22-33 ◽  
Author(s):  
Brynne D. Ovalle ◽  
Rahul Chakraborty
Keyword(s):  
International Relations ◽  
Identity Construction ◽  
Social Theory ◽  
Power Relations ◽  
Linguistic Diversity ◽  
Cultural Organization ◽  
Using Data ◽  
The Individual ◽  
The Impact ◽  
The Relationship

This article has two purposes: (a) to examine the relationship between intercultural power relations and the widespread practice of accent discrimination and (b) to underscore the ramifications of accent discrimination both for the individual and for global society as a whole. First, authors review social theory regarding language and group identity construction, and then go on to integrate more current studies linking accent bias to sociocultural variables. Authors discuss three examples of intercultural accent discrimination in order to illustrate how this link manifests itself in the broader context of international relations (i.e., how accent discrimination is generated in situations of unequal power) and, using a review of current research, assess the consequences of accent discrimination for the individual. Finally, the article highlights the impact that linguistic discrimination is having on linguistic diversity globally, partially using data from the United Nations Educational, Scientific and Cultural Organization (UNESCO) and partially by offering a potential context for interpreting the emergence of practices that seek to reduce or modify speaker accents.

Business: Making Cents of Coding Systems: Billing for Professional Services

2010 ◽  
Vol 20 (1) ◽  
pp. 3-8
Author(s):  
Dee Adams Nikjeh
Keyword(s):  
Professional Services ◽  
Speech Language Pathology ◽  
Coding Systems ◽  
Language Pathology ◽  
Program Funding ◽  
Fee Schedule ◽  
Procedure Codes ◽  
Relationship Of ◽  
The Impact ◽  
The Relationship

Abstract Administrators and supervisors face daily challenges over issues such as program funding, service fees, correct coding procedures, and the ever-changing healthcare regulations. Receiving equitable reimbursement for speech-language pathology and audiology services necessitates an understanding of federal coding and reimbursement systems. This tutorial provides information pertaining to two major healthcare coding systems and explains the relationship of these systems to clinical documentation, the Medicare Physician Fee Schedule and equitable reimbursement. An explanation of coding edits and coding modifiers is provided for use in those occasional atypical situations when the standard use of procedural coding may not be appropriate. Also included in this tutorial is a brief discussion of the impact that the Medicare Improvements for Patients and Providers Act of 2008 (HR 6331 Medicare Improvements for Patients and Providers Act [MIPPA], 2008) has had on the valuation of speech-language pathology procedure codes.

The Need to Belong and the Relationship Between Loneliness and Health

2014 ◽  
Vol 22 (4) ◽  
pp. 194-201 ◽  
Author(s):  
Freda-Marie Hartung ◽  
Britta Renner
Keyword(s):  
Individual Differences ◽  
Social Isolation ◽  
Social Situation ◽  
First Year ◽  
Health State ◽  
Need To Belong ◽  
First Year University ◽  
Perceived Social Isolation ◽  
The Impact ◽  
The Relationship

Humans are social animals; consequently, a lack of social ties affects individuals’ health negatively. However, the desire to belong differs between individuals, raising the question of whether individual differences in the need to belong moderate the impact of perceived social isolation on health. In the present study, 77 first-year university students rated their loneliness and health every 6 weeks for 18 weeks. Individual differences in the need to belong were found to moderate the relationship between loneliness and current health state. Specifically, lonely students with a high need to belong reported more days of illness than those with a low need to belong. In contrast, the strength of the need to belong had no effect on students who did not feel lonely. Thus, people who have a strong need to belong appear to suffer from loneliness and become ill more often, whereas people with a weak need to belong appear to stand loneliness better and are comparatively healthy. The study implies that social isolation does not impact all individuals identically; instead, the fit between the social situation and an individual’s need appears to be crucial for an individual’s functioning.

Investigating the Relationship Between Self-Esteem and Stigma Among Young Adults With History of Suicide Attempts

Crisis ◽  
2016 ◽  
Vol 37 (4) ◽  
pp. 265-270 ◽  
Author(s):  
Meshan Lehmann ◽  
Matthew R. Hilimire ◽  
Lawrence H. Yang ◽  
Bruce G. Link ◽  
Jordan E. DeVylder
Keyword(s):  
Young Adults ◽  
Suicide Attempts ◽  
Self Esteem ◽  
High Risk Population ◽  
High Functioning ◽  
People With Mental Illness ◽  
History Of ◽  
The Individual ◽  
The Impact ◽  
The Relationship

Abstract. Background: Self-esteem is a major contributor to risk for repeated suicide attempts. Prior research has shown that awareness of stigma is associated with reduced self-esteem among people with mental illness. No prior studies have examined the association between self-esteem and stereotype awareness among individuals with past suicide attempts. Aims: To understand the relationship between stereotype awareness and self-esteem among young adults who have and have not attempted suicide. Method: Computerized surveys were administered to college students (N = 637). Linear regression analyses were used to test associations between self-esteem and stereotype awareness, attempt history, and their interaction. Results: There was a significant stereotype awareness by attempt interaction (β = –.74, p = .006) in the regression analysis. The interaction was explained by a stronger negative association between stereotype awareness and self-esteem among individuals with past suicide attempts (β = –.50, p = .013) compared with those without attempts (β = –.09, p = .037). Conclusion: Stigma is associated with lower self-esteem within this high-functioning sample of young adults with histories of suicide attempts. Alleviating the impact of stigma at the individual (clinical) or community (public health) levels may improve self-esteem among this high-risk population, which could potentially influence subsequent suicide risk.

Assessing the Impact of Suicide Exclusion Periods on Life Insurance

Crisis ◽  
2010 ◽  
Vol 31 (4) ◽  
pp. 217-223 ◽  
Author(s):  
Paul Yip ◽  
David Pitt ◽  
Yan Wang ◽  
Xueyuan Wu ◽  
Ray Watson ◽  
...  
Keyword(s):  
Life Insurance ◽  
Accidental Death ◽  
Insurance Policy ◽  
Death Rates ◽  
Insurance Policies ◽  
Suicidal Death ◽  
Insured Individual ◽  
The Impact ◽  
Insurance Data ◽  
The Relationship

Background: We study the impact of suicide-exclusion periods, common in life insurance policies in Australia, on suicide and accidental death rates for life-insured individuals. If a life-insured individual dies by suicide during the period of suicide exclusion, commonly 13 months, the sum insured is not paid. Aims: We examine whether a suicide-exclusion period affects the timing of suicides. We also analyze whether accidental deaths are more prevalent during the suicide-exclusion period as life-insured individuals disguise their death by suicide. We assess the relationship between the insured sum and suicidal death rates. Methods: Crude and age-standardized rates of suicide, accidental death, and overall death, split by duration since the insured first bought their insurance policy, were computed. Results: There were significantly fewer suicides and no significant spike in the number of accidental deaths in the exclusion period for Australian life insurance data. More suicides, however, were detected for the first 2 years after the exclusion period. Higher insured sums are associated with higher rates of suicide. Conclusions: Adverse selection in Australian life insurance is exacerbated by including a suicide-exclusion period. Extension of the suicide-exclusion period to 3 years may prevent some “insurance-induced” suicides – a rationale for this conclusion is given.

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