scholarly journals Tropical forest recovery from logging: a 24 year silvicultural experiment from Central Africa

2013 ◽  
Vol 368 (1625) ◽  
pp. 20120302 ◽  
Author(s):  
Sylvie Gourlet-Fleury ◽  
Frédéric Mortier ◽  
Adeline Fayolle ◽  
Fidèle Baya ◽  
Dakis Ouédraogo ◽  
...  
Keyword(s):  
Central Africa ◽  
Dry Mass ◽  
Forest Recovery ◽  
Growth And Survival ◽  
Disturbance Intensity ◽  
Silvicultural Treatments ◽  
Management Plans ◽  
Felling Cycle ◽  
Positive Effect

Large areas of African moist forests are being logged in the context of supposedly sustainable management plans. It remains however controversial whether harvesting a few trees per hectare can be maintained in the long term while preserving other forest services as well. We used a unique 24 year silvicultural experiment, encompassing 10 4 ha plots established in the Central African Republic, to assess the effect of disturbance linked to logging (two to nine trees ha −1 greater than or equal to 80 cm DBH) and thinning (11–41 trees ha −1 greater than or equal to 50 cm DBH) on the structure and dynamics of the forest. Before silvicultural treatments, above-ground biomass (AGB) and timber stock (i.e. the volume of commercial trees greater than or equal to 80 cm DBH) in the plots amounted 374.5 ± 58.2 Mg ha −1 and 79.7 ± 45.9 m 3 ha −1 , respectively. We found that (i) natural control forest was increasing in AGB (2.58 ± 1.73 Mg dry mass ha −1 yr −1 ) and decreasing in timber stock (−0.33 ± 1.57 m 3 ha −1 yr −1 ); (ii) the AGB recovered very quickly after logging and thinning, at a rate proportional to the disturbance intensity (mean recovery after 24 years: 144%). Compared with controls, the gain almost doubled in the logged plots (4.82 ± 1.22 Mg ha −1 yr −1 ) and tripled in the logged + thinned plots (8.03 ± 1.41 Mg ha −1 yr −1 ); (iii) the timber stock recovered slowly (mean recovery after 24 years: 41%), at a rate of 0.75 ± 0.51 m 3 ha −1 yr −1 in the logged plots, and 0.81 ± 0.74 m 3 ha −1 yr −1 in the logged + thinned plots. Although thinning significantly increased the gain in biomass, it had no effect on the gain in timber stock. However, thinning did foster the growth and survival of small- and medium-sized timber trees and should have a positive effect over the next felling cycle.

Crop rotations with clover and their productivity

2020 ◽  
Author(s):  
Ol'ga Gladysheva ◽  
Oksana Artyuhova ◽  
Vera Svirina
Keyword(s):  
Forest Soil ◽  
Crop Rotation ◽  
Gray Forest Soil ◽  
Arable Land ◽  
Perennial Grasses ◽  
Crop Rotations ◽  
Field Crop ◽  
Pure Steam ◽  
Positive Effect

The results of long-term research in experiments with crop rotations with different clover saturation are presented. It is shown that the cluster has a positive effect on the main indicators of vegetation of dark-gray forest soil. The introduction of two fields of perennial grasses into the six-field crop rotation significantly increases both the humus reserves and increases the productivity of arable land by 1.5–2 times compared to the crop rotation with a field of pure steam.

The depressing (negative) effect of oestradiol benzoate on the in vitro secretion of LH and FSH by the pituitary gland of the LRH-pretreated long-term ovariectomized rat changes into the augmentative (positive) effect after discontinuation of the LRH-pretreatment

1985 ◽  
Vol 110 (3) ◽  
pp. 329-337 ◽  
Author(s):  
G. A. Schuiling ◽  
H. Moes ◽  
T. R. Koiter
Keyword(s):  
Depressing Effect ◽  
Ovx Rats ◽  
Gonadotrophin Secretion ◽  
Oestradiol Benzoate ◽  
Negative Effect ◽  
Positive Effect ◽  
Perifusion System

Abstract. The effect of pretreatment in vivo with oestradiol benzoate on in vitro secretion of LH and FSH was studied in long-term ovariectomized (OVX) rats both at the end of a 5-day continuous in vivo pretreatment with LRH and 4-days after cessation of such LRH pretreatment. Rats were on day 0 sc implanted with osmotic minipumps which released LRH at the rate of 250 ng/h. Control rats were implanted with a piece of silicone elastomer with the dimensions of a minipump. On days 2 and 4 the rats were injected with either 3 μg EB or with oil. On day 5 part of the rats were decapitated and the in vitro autonomous (i.e. non-LRH-stimulated) and 'supra-maximally' LRHstimulated release of LH and FSH was studied using a perifusion system. From other rats the minipumps were removed on day 5 and perifusion was performed on day 9. On the 5th day of the in vivo LRH pretreatment the pituitary LH/FSH stores were partially depleted; the pituitaries of the EB-treated rats more so than those of the oil-injected rats. EB alone had no significant effect on the content of the pituitary LH- and FSH stores. On day 9, i.e. 4 days after removal of the minipumps, the pituitary LH and FSH contents had increased in both the oil- and the EB injected rats, but had not yet recovered to control values. In rats not subjected to the 5-days pretreatment with LRH EB had a positive effect on the supra-maximally LRH-stimulated secretion of LH and FSH as well as on the non-stimulated secretion of LH. EB had no effect on the non-stimulated secretion of FSH. After 5 days of in vivo pretreatment with LRH only, the in vitro non-stimulated and supra-maximally LRH-stimulated secretion of both LH and FSH were strongly impaired, the effect correlating well with the LRH-induced depletion of the pituitary LH/FSH stores. In such LRH-pretreated rats EB had on day 5 a negative effect on the (already depressed) LRH-stimulated secretion of LH (not on that of FSH). EB had no effect on the non-stimulated LH/FSH secretion. It could be demonstrated that the negative effect of the combined LRH/EB pretreatment was mainly due to the depressing effect of this treatment on the pituitary LH and FSH stores: the effect of oestradiol on the pituitary LRH-responsiveness (release as related to pituitary gonadotrophin content) remained positive. In LRH-pretreated rats, however, this positive effect of EB was smaller than in rats not pretreated with LRH. Four days after removal of the minipumps there was again a positive effect of EB on the LRH-stimulated secretion of LH and FSH as well as on the non-stimulated secretion of LH. The positive effect of EB on the pituitary LRH-responsiveness was as strong as in rats which had not been exposed to exogenous LRH. The non-stimulated secretion of FSH was again not affected by EB. The results demonstrate that the effect of EB on the oestrogen-sensitive components of gonadotrophin secretion consists of two components: an effect on the pituitary LRH-responsiveness proper, and an effect on the pituitary LH/FSH stores. The magnitude of the effect of EB on the LRH-responsiveness is LRH dependent: it is very weak (almost zero) in LRH-pretreated rats, but strong in rats not exposed to LRH as well as in rats of which the LRH-pretreatment was stopped 4 days previously. Similarly, the effect of EB on the pituitary LH and FSH stores is LRH-dependent: in the absence of LRH, EB has no influence on the contents of these stores, but EB can potentiate the depleting effect of LRH on the LH/FSH-stores. Also this effect disappear after cessation of the LRH-pretreatment.

Hydrogeological responses in tropical mountainous springs

2019 ◽  
Author(s):  
Ricardo Sánchez-Murillo
Keyword(s):  
Costa Rica ◽  
Isotope Composition ◽  
Central Valley ◽  
Distribution Functions ◽  
Geochemical Composition ◽  
Transit Times ◽  
Management Plans ◽  
Best Fit ◽  
Term Data

This study presents a hydrogeochemical analysis of spring responses (2013-2017) in the tropical mountainous region of the Central Valley of Costa Rica. The isotopic distribution of δ18O and δ2H in rainfall resulted in a highly significant meteoric water line: δ2H = 7.93×δ18O + 10.37 (r2=0.97). Rainfall isotope composition exhibited a strong dependent seasonality. The isotopic variation (δ18O) of two springs within the Barva aquifer was simulated using the FlowPC program to determine mean transit times (MTTs). Exponential-piston and dispersion distribution functions provided the best-fit to the observed isotopic composition at Flores and Sacramento springs, respectively. MTTs corresponded to 1.23±0.03 (Sacramento) and 1.42±0.04 (Flores) years. The greater MTT was represented by a homogeneous geochemical composition at Flores, whereas the smaller MTT at Sacramento is reflected in a more variable geochemical response. The results may be used to enhance modelling efforts in central Costa Rica, whereby scarcity of long-term data limits water resources management plans.

Удобрение огурца в Западной Сибири

2018 ◽  
Author(s):  
Т.А. Кuznetsova ◽  
N.А. Коlpakov
Keyword(s):  
Organic Fertilizers ◽  
Control Variant ◽  
Positive Effect ◽  
Different Doses

Показано, что длительное применение как минеральных, так и органических удобрений в различных дозах и сочетаниях положительно влияет на урожайность огурца. Установлено, что в условиях 14-й ротации урожайность на всех вариантах опыта была выше, чем на контрольном варианте и составила 16,4–22,3 т/га, против 16,0 т/га в контроле.The authors show that the long-term use of both mineral and organic fertilizers in different doses and combinations has a positive effect on the yield of cucumber. It was found that under 14 rotation conditions the yield on all variants of the experiment was higher than on the control variant and amounted to 16.4–22.3 t/ha, against 16.0 t/ha on the control.

Possibilities and prospects of conservative therapy for endometriosis, as a chronical progressing disease (review of literature)

GYNECOLOGY ◽  
2020 ◽  
Vol 22 (1) ◽  
pp. 14-18 ◽  
Author(s):  
Tatyana Yu. Pestrikova ◽  
Elena A. Yurasova ◽  
Igor V. Yurasov
Keyword(s):  
Quality Of Life ◽  
Abnormal Uterine Bleeding ◽  
Modern Medicine ◽  
Reproductive Age ◽  
Aim Analysis ◽  
Scientific Publications ◽  
Terra Incognita ◽  
Positive Effect

Relevance. Endometriosis is a common gynecological disease that affects up to 10% of women of reproductive age worldwide and is the main cause of pain and infertility. Endometriosis is a disease, although it has been known for a long time, nevertheless, in many ways it represents terra incognita for modern medicine. Aim. Analysis of literature on the feasibility of long-term and the use of the drug dienogest 2 mg (Vizanne), which has a positive effect on the quality of life of patients with endometriosis. Materials and methods. To write this review, a search was made for domestic and foreign publications in Russian and international search engines (PubMed, eLibrary, etc.) over the past 13 years. The review included articles from peer-reviewed literature. Results. The review presents data on the difficulties of verifying the diagnosis of endometriosis due to a combination of this pathology with pain, infertility, abnormal uterine bleeding. The pathogenesis of the origin of endometriosis-associated pain is presented. The efficacy of the use of the drug dienogest (Vizanne), which has a powerful antiproliferative effect that reduces the main symptoms of endometriosis (pain, bleeding), is substantiated. The expediency of long-term and safe use of the drug dienogest (Vizanne), which has a positive effect on the quality of life of patients with endometriosis, has been proved. Conclusions. Numerous scientific publications confirm the feasibility of prolonged use of the drug dienogest (Vizanne), to achieve remission during endometriosis.

Consumer Awareness, Consumer Protection, Service Quality and Loyalty: The Case of Long-term Insurance Consumers in Namibia

2019 ◽  
Vol 118 (8) ◽  
pp. 172-189
Author(s):  
Magreth B Tjizumaue ◽  
Krishna Govender
Keyword(s):  
Service Quality ◽  
Consumer Protection ◽  
Structural Equation ◽  
Insurance Industry ◽  
Business Practices ◽  
Consumer Awareness ◽  
Growth And Survival ◽  
Term Insurance ◽  
Protection Legislation

Due to the absence of appropriate Consumer Protection legislation in Namibia, there seems to be a lack of consumer protection, which may result in consumers being exploited. Since the literature reveals that Consumer Awareness, Consumer Protection, Service Quality and Customer Satisfaction influence Customer Loyalty, the aforementioned relationship was explored among consumers of long-term insurance products in Namibia. The researcher embedded the study in the Services Marketing and User’s Satisfaction/Dissatisfaction theory and developed a framework for creating a more aware consumer and thus contribute to the growth and survival of the long-term insurance industry in Namibia.  A survey was conducted using a questionnaire, among a judgmental sample of 407 long-term insurance consumers in Namibia and Structural Equation Modelling was used to analyse (eight) hypothesized relationships among the research constructs alluded to in the title of this study. In summary, it was ascertained that if the customers are fully aware (have sufficient knowledge of the products and their consumer rights), they will feel protected against unfair business practices. Furthermore, if they perceive having received quality services, they are more likely to be satisfied with the service provider and will therefore, remain loyal.

PENGARUH INFRASTRUKTUR SECARA SPASIAL TERHADAP KONVERGENSI PERTUMBUHAN EKONOMI DI INDONESIA

INFO ARTHA ◽  
2017 ◽  
Vol 1 ◽  
pp. 17-28
Author(s):  
Anisa Fahmi
Keyword(s):  
Economic Growth ◽  
Regional Economics ◽  
Developed Countries ◽  
Road Infrastructure ◽  
Long Run ◽  
Catch Up ◽  
The Developed Countries ◽  
Positive Effect ◽  
Neoclassical Growth Theory

Motivated by inter-regional disparities condition that occurs persistently, this study examines the Indonesian economy in the long run in order to know whether it tends to converge or diverge. This convergence is based on the Solow Neoclassical growth theory assuming the existence of diminishing returns to capital so that when the developed countries reach steady state conditions, developing countries will continuously grow up to 'catch-up' with developed countries. Based on regional economics perspective, each region can not be treated as a stand-alone unit,therefore, this study also focuses on the influence of spatial dependency and infrastructure. Economical and political situations of a region will influence policy in that region which will also have an impact to the neighboring regions. The estimation results of spatial cross-regressive model using fixed effect method consistently confirmed that the Indonesian economy in the long term will likely converge with a speed of 8.08 percent per year. Other findings are road infrastructure has a positive effect on economic growth and investment and road infrastructure are spatially showed a positive effect on economic growth. In other words, the investment and infrastructure of a region does not only affect the economic growth of that region but also to the economy of the contiguous regions. 

scholarly journals Implementation Intentions to Reduce Smoking: A Systematic Review of the Literature

2020 ◽  
Author(s):  
Charlotte J Hagerman ◽  
Rebecca K Hoffman ◽  
Sruthi Vaylay ◽  
Tonya Dodge
Keyword(s):  
Systematic Review ◽  
Implementation Intentions ◽  
Experimental Studies ◽  
Implementation Intention ◽  
Promising Tool ◽  
Current Systematic Review ◽  
Long Term Follow Up ◽  
Positive Effect

Abstract Implementation intentions are a goal-setting technique in which an individual commits to perform a particular behavior when a specific context arises. Recently, researchers have begun studying how implementation intention (II) interventions can facilitate antismoking efforts. The current systematic review synthesized results of experimental studies that tested the effect of an II intervention on smoking cognitions and behavior. Of 29 reviewed articles, 11 studies met inclusion criteria. Nine studies (81.8%) tested an II intervention as a cessation tool for current smokers, whereas two tested II interventions as a tool to prevent smoking among predominantly nonsmoking adolescents. A majority of the studies (66.7%) testing II interventions as a cessation tool reported a positive effect on cessation at long-term follow-up. Of the two studies testing II interventions as a tool for prevention, one study found a positive effect on long-term follow-up. Methodology varied between the studies, highlighting the discrepancies between what researchers consider “implementation intentions” to be. II interventions are a promising tool for antismoking efforts, but more research is necessary to determine the best methodology and the populations for whom this intervention will be most effective. Implications Brief, free, and easily scalable, II interventions to prevent smoking are highly attractive for antismoking efforts. This review outlines the circumstances under which II interventions have demonstrated effectiveness in helping people resist smoking cigarettes. We illuminate gaps in the existing literature, limitations, methodological discrepancies between studies, and areas for future study.

scholarly journals The Demerger Impact upon Sustainable Development of Economic Entities: Evidence from Romania

2021 ◽  
Vol 13 (15) ◽  
pp. 8316
Author(s):  
Camelia Mirela Baba ◽  
Constantin Duguleană ◽  
Marius Sorin Dincă ◽  
Liliana Duguleană ◽  
Gheorghița Dincă
Keyword(s):  
Sustainable Development ◽  
Business Strategies ◽  
The Sustainable Development ◽  
Ex Post ◽  
Before And After ◽  
Almost All ◽  
The Impact ◽  
Profitability Ratios ◽  
Positive Effect

The Covid-19 induced economic crisis has significantly affected almost all businesses from nearly every sector, causing severe financial problems, lack of cash assets, and decrease of revenues. In this context, the economic entities were forced to look for adjustment and rescue solutions of their activities. One possible solution for the recovery and reorganization of economic entities’ activities is demerger. This paper evaluates the impact of demerger upon the sustainable development of economic entities in terms of economic efficiency and financial performances. To achieve this goal, a statistical analysis of profitability ratios before and after the demerger, as well as a structural analysis of 268 demerger projects for the April 2012–April 2021 period, were performed. The results attest there are no significant differences between the ex-ante and ex-post financial performances. However, demerger seems to have a positive effect upon analyzed companies helping them to overcome economic hardships, rethink their business strategies, and continue their activity in the medium and long-term time horizon.

scholarly journals Domain Adaptation for Semantic Segmentation of Historical Panchromatic Orthomosaics in Central Africa

2021 ◽  
Vol 10 (8) ◽  
pp. 523
Author(s):  
Nicholus Mboga ◽  
Stefano D’Aronco ◽  
Tais Grippa ◽  
Charlotte Pelletier ◽  
Stefanos Georganos ◽  
...  
Keyword(s):  
Land Cover ◽  
Domain Adaptation ◽  
Central Africa ◽  
Semantic Segmentation ◽  
Target Domain ◽  
Convolutional Networks ◽  
Fully Convolutional Networks ◽  
The Cost ◽  
Performance Gains

Multitemporal environmental and urban studies are essential to guide policy making to ultimately improve human wellbeing in the Global South. Land-cover products derived from historical aerial orthomosaics acquired decades ago can provide important evidence to inform long-term studies. To reduce the manual labelling effort by human experts and to scale to large, meaningful regions, we investigate in this study how domain adaptation techniques and deep learning can help to efficiently map land cover in Central Africa. We propose and evaluate a methodology that is based on unsupervised adaptation to reduce the cost of generating reference data for several cities and across different dates. We present the first application of domain adaptation based on fully convolutional networks for semantic segmentation of a dataset of historical panchromatic orthomosaics for land-cover generation for two focus cities Goma-Gisenyi and Bukavu. Our experimental evaluation shows that the domain adaptation methods can reach an overall accuracy between 60% and 70% for different regions. If we add a small amount of labelled data from the target domain, too, further performance gains can be achieved.

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