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1992. A study on African animal trypanosomosis in four areas of Senegal
- Creator:
- Ravel, Sophie, Mediannikov, Oleg, Bossard, Géraldine, Desquesnes, Marc, Cuny, Gérard, and Davoust, Bernard
- Format:
- electronic, počítač, and online zdroj
- Type:
- model:article and TEXT
- Subject:
- psi, osli, skot, epidemiologie, dogs, donkeys, cattle, epidemiology, Trypanosoma congolense, 2, and 59
- Language:
- English
- Description:
- In Senegal, several areas provide great potential for agriculture and animal production, but African animal trypanosomosis (AAT) is one of the major constraints to the development of more effective livestock production systems. A study was conducted to assess the current situation of AAT in this country. Surveys were carried out between June 2011 and September 2012 in four different areas: Dakar, Sine Saloum, Kedougou region and Basse Casamance in several animal species: dogs (152), donkeys (23), horses (63), sheep (43), goats (52) and cattle (104), distributed in the four sites. Molecular tools (PCR) indicated 3.4% positive animals including dogs, donkeys, a goat and cattle. The savannah type of Trypanosoma congolense Broden, 1904 (53% of positive cases) and the forest type of T. congolense (subgenus Nannomonas Hoare, 1964) were predominant. Trypanosoma vivax Ziemann, 1905 (subgenus Duttonella Chalmers, 1918) was only present in one animal and no trypanosome of the subgenus Trypanozoon Lühe, 1906 was found. Half of the positive cases were detected in Sine Saloum, where T. congolense savannah-type was predominant, and the other half in Basse Casamance, where T. congolense forest-type was predominant; no cases were found in Dakar or in the Kedougou region. A high risk of infection in dogs with T. congolense savannah-type was shown in Sine Saloum, requiring prevention and control of dogs in this area. The involvement of tsetse flies in the transmission of T. congolense in Sine Saloum and Basse Casamance is discussed., Sophie Ravel, Oleg Mediannikov, Géraldine Bossard, Marc Desquesnes, Gérard Cuny, Bernard Davoust., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
1993. A study on decentralized H∞ feedback control systems with local quantizers
- Creator:
- Zhai, Guisheng, Chen, Ning, and Gui, Weihua
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- decentralized H∞ feedback control system, quantizer, quantization, matrix inequality, and output feedback
- Language:
- English
- Description:
- In this paper, we study decentralized H∞ feedback control systems with quantized signals in local input-output (control) channels. We first assume that a decentralized output feedback controller has been designed for a multi-channel continuous-time system so that the closed-loop system is Hurwitz stable and a desired H∞ disturbance attenuation level is achieved. However, since the local measurement outputs are quantized by a general quantizer before they are passed to the controller, the system's performance is not guaranteed. For this reason, we propose a local-output-dependent strategy for updating the quantizers' parameters, so that the closed-loop system is asymptotically stable and achieves the same H∞ disturbance attenuation level. We also extend the discussion and the result to the case of multi-channel discrete-time H∞ feedback control systems.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
1994. A study on global stabilization of periodic orbits in discrete-time chaotic systems by using symbolic dynamics
- Creator:
- Suzuki, Masayasu and Sakamoto, Noboru
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- symbolic dynamics, chaos control, and global stability
- Language:
- English
- Description:
- In this report, a control method for the stabilization of periodic orbits for a class of one- and two-dimensional discrete-time systems that are topologically conjugate to symbolic dynamical systems is proposed and applied to a population model in an ecosystem and the Smale horseshoe map. A periodic orbit is assigned as a target by giving a sequence in which symbols have periodicity. As a consequence, it is shown that any periodic orbits can be globally stabilized by using arbitrarily small control inputs. This work is a new attempt to systematically design a control system based on symbolic dynamics in the sense that one estimates the magnitude of control inputs and analyzes the Lyapunov stability.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
1995. A study on molecular mechanisms of adiposis induced by long-term treatment of high-fat and high-sucrose in C57BL/6J mice
- Creator:
- Li, X., Tu, P. , Umar, M., Liu, Q. , Luo, W. , Yang, X., Zhu, J. , Kong, D., and Li, M.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- obesity, dietary, epigenetic, DNA methylation, and DNMT1
- Language:
- English
- Description:
- Adiposis is reputed as a twin disease of type 2 diabetes and greatly harmful to human health. In order to understand the molecular mechanisms of adiposis, the changes of physiological, pathological, epigenetic and correlative gene expression were investigated during the adiposis development of C57BL/6J mice induced by long time (9 months) high-fat and high-sucrose diet (HFSD) sustainably. The results showed that mRNA transcription level of the Leptin, Glut4 and Glut2 genes have been obviously changed, which exhibit a negative correlation with methylation on their promoter DNA. The results also revealed that HFSD induced higher level of DNA methyltransferase 1 (DNMT1) in fat tissue might play important role in regulating the changes of methylation pattern on Glut4 and Leptin genes, and which might be one of the molecular mechanisms for the adiposis development.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
1996. A subcopula based dependence measure
- Creator:
- Erdely, Arturo
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- subcopula, dependence, and concordance
- Language:
- English
- Description:
- A dependence measure for arbitrary type pairs of random variables is proposed and analyzed, which in the particular case where both random variables are continuous turns out to be a concordance measure. Also, a sample version of the proposed dependence measure based on the empirical subcopula is provided, along with an R package to perform the corresponding calculations.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
1997. A subpressor dose of angiotensin II elevates blood pressure in a normotensive rat model by oxidative stress
- Creator:
- Govender, M. M. and Nadar, A.
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, oxidační stres, hypertenze, oxidative stress, hypertension, angiotensin II, subpressor, superoxide radical, 14, and 612
- Language:
- English
- Description:
- Oxidative stress is an imbalance between free radicals and antioxidants, and is an important etiological factor in the development of hypertension. Recent experimental evidence suggests that subpressor doses of angiotensin II elevate oxidative stress and blood pressure. We aimed to investigate the oxidative stress related mechanism by which a subpressor dose of angiotensin II induces hypertension in a normotensive rat model. Normotensive male Wistar rats were infused with a subpressor dose of angiotensin II for 28 days. The control group was sham operated and infused with saline only. Plasma angiotensin II and H2O2 levels, whole-blood glutathione peroxidase, and AT-1a, Cu/Zn SOD, and p22phox mRNA expression in the aorta was assessed. Systolic and diastolic blood pressures were elevated in the experimental group. There was no change in angiotensin II levels, but a significant increase in AT-1a mRNA expression was found in the experimental group. mRNA expression of p22phox was increased significantly and Cu/Zn SOD decreased significantly in the experimental group. There was no significant change to the H2O2 and GPx levels. Angiotensin II manipulates the free radical-antioxidant balance in the vasculature by selectively increasing O2 - production and decreasing SOD activity and causes an oxidative stress induced elevation in blood pressure in the Wistar rat., M. M. Govender, A. Nadar., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1998. A sucker for the job: morphology and functioning of suckers of polystomatid monogeneans
- Creator:
- Heyns Du Preez, Louis and Theunissen, Maxine
- Format:
- počítač and online zdroj
- Type:
- model:article and TEXT
- Subject:
- Polystomatidae, Monogenea, sclerite, morphology, haptoral sucker, type I, type II, type III, and type IV
- Language:
- English
- Description:
- Monogeneans rely on firm attachment to often flexible and uneven surfaces and are renowned for their effective posterior attachment structures in the form of adhesives, clamps, hamuli and suckers. Polystomatids do not secrete adhesives and do not have clamps. While only some have hamuli, all have suckers in the adult form. Three different types of haptoral suckers have been described based on basic morphology but have never been studied in depth. Using enzyme digestion and light (differential interference contrast), confocal and scanning electron microscopy, we examined representatives and propose four sucker types. Haptoral sucker Type I are symmetrical soft, flexible, cup- to disk-shaped suckers and are found in all polystomes infecting frogs and salamanders. Type II suckers are symmetrical soft, flexible, cup-shaped suckers with a hollow continuous skeletal ring and no other skeletal elements. They are found in species of Nanopolystoma Du Preez, Wilkinson et Huyse, 2008 infecting caecilians. Type III suckers are symmetrical firm, cup-shaped suckers with elaborate skeletal elements that contribute to a secure grip on the host tissue. This type of sucker is found in all polystomes infecting freshwater turtles and the common hippopotamus. Type IV suckers are asymmetrical with an elaborate series of long, thin sclerites with terminal spines or hooks. This type of sucker is only known from Concinnocotyla australensis (Reichenbach-Klinke, 1966) infecting the Australian lungfish. These different sucker types are crucial for the survival of polystomatid flatworms within their respective microhabitats.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
1999. A sunny day at the beach: ecophysiological assessment of the photosynthetic adaptability of coastal dune perennial herbs by chlorophyll fluorescence parameters
- Creator:
- Bermúdez, R. and Retuerto, R.
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, Eryngium maritimum, Euphorbia paralias, light curve, Matthiola sinuata, nonphotochemical quenching, Pancratium maritimum, photochemical quenching, quantum yield of photosystem II, 2, and 581
- Language:
- Multiple languages
- Description:
- Light is critical in determining plant structure and functioning in dune ecosystems, which are characterised by high incident and reflected radiation. Light variations demand great plasticity of the photosynthetic apparatus. This study assessed the phenotypic plasticity of foredune species by analysing their light response and dark recovery curves measured under field conditions. We also addressed the question how coexisting species, structurally distinct, differed in their photochemical efficiency in response to short-term changes in light. Finally, we examined how the varying intensity of stressors operating along a dune gradient affected responses to light. The species differed in light use strategies but showed similar patterns of the dark recovery. Species differences in photochemistry varied seasonally, with species being winter specialists, summer specialist or generalists. Some aspects of their photochemistry varied significantly along the gradient. Unexpectedly, other traits did not vary as predicted. For example, changes in light efficiency of plants along the gradient were not consistent with assumed directional changes in the severity of stressors. The different light use strategies observed in coexisting species did not conform to the prediction that stressors constrain the range of possible functional designs in harsh environments. However, the species followed very similar patterns of post-illumination recovery, which suggests that evolutionary pressures might be acting to maintain similar recovery mechanisms. Our results indicated that dune gradients might be nondirectional, which determines unpredictable patterns of variation in leaf traits along the dune gradient. Seasonal differences in the relative performance may allow species to coexist where otherwise one species would exclude the other., R. Bermúdez, R. Retuerto., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2000. A survey of HIV and HCV among female prison inmates in Portugal
- Creator:
- Barros, Henrique
- Type:
- model:article and TEXT
- Language:
- English
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public