Search results for "lake"

Water quality in cutaway peatland lakes in Seda mire, Latvia

2011

Remediation of industrially-milled peatland is an important task in the sustainable management of natural resources. Several approaches for wetland restoration, depending on local climatic and hydrological conditions, topography, physico-chemical properties of peat, as well as peat mining techniques, have been developed worldwide. However, most of the restoration activities include regulation of hydrological regime and surface topography in order to reintroduce typical bog vegetation, especially, Sphagnum cover, and to restore the peatland’s ecosystem close to its original conditions (Gorham and Rochefort, 2003; Farrell and Doyle, 2003; Lamers et al., 2002). In many countries, a significant…

Extensive Antibiotic and Antimalarial Prescription Rate among Children with Acute Febrile Diseases in the Lake Victoria Region, Tanzania

2021

Abstract Objectives Acute mosquito-borne febrile diseases pose a threat to children in the Sub-Saharan-Africa with ∼272 000 children dying worldwide from malaria in 2018. Although the awareness for malaria in this area has increased due to improved health education, the apparent decline of actual malaria cases has not affected clinical practice significantly. This study collected clinical and epidemiologic data of children presenting with acute febrile diseases in order delineate their diagnostic and therapeutic management. Methods A hospital-based cross-sectional clinical study was conducted at the Sekou Toure Regional Referral Hospital in Tanzania. Children between 1 month and 12 years of…

The Spatial Distribution of Perch (Perca fluviatilis) Ectoparasites and the Effect of Chemical Water Quality Parameters on Ectoparasite Spatial Niche…

2018

Abstract Seasonal changes of abiotic factors and their influence on parasite occurrence have repeatedly been studied. Most of the studies have been conducted to evaluate the effect of water physicochemical parameters on changes in the intensity of infection, prevalence and component community of a number of parasite species. However, insufficient attention has been paid to the link between water quality parameters and spatial niche size of ectoparasites. The distribution of ectoparasite species on perch (Perca fluviatilis L.) was studied to establish whether seasonal changes of water quality parameters are associated with ectoparasite spatial niche size. The concentration of phosphates (PO4…

2014

Abstract. Dynamical and microphysical processes in pyroconvective clouds in mid-latitude conditions are investigated using idealized three-dimensional simulations with the Active Tracer High resolution Atmospheric Model (ATHAM). A state-of-the-art two-moment microphysical scheme building upon a realistic parameterization of cloud condensation nuclei (CCN) activation has been implemented in order to study the influence of aerosol concentration on cloud development. The results show that aerosol concentration influences the formation of precipitation. For low aerosol concentrations (NCN = 200 cm−3), rain droplets are rapidly formed by autoconversion of cloud droplets. This also triggers the f…

Model Analysis of Hydrometeor Scattering Effects on Free Space Near-Infrared Links

2012

A promising technology for peer-to-peer connections and urban area networks is represented by wireless communications through free space using optical carrier (Free Space Optics, FSO). This technology ensures high data rates, with relatively low error rates, low power consumption and inherent security. Nevertheless FSO links are quite sensitive to atmospheric condition. Fog droplets, but also raindrops and snowflakes, may introduce severe path attenuation which drastically reduces the channel availability. A parametric model to simulate droplets scattering effects over the FSO link in terms of extinction coefficient, albedo factor and asymmetry coefficient as function of the particle water …

Orbscan Pachymetry: Differences between observers when carrying out measurements of the corneal thickness

2005

espanolObjetivo: Estudiar el espesor corneal y la variabilidad entre observadores de las mediciones del espesor corneal empleando paquimetria Orbscan. Metodos: Analizamos el espesor corneal central y paracentral de 30 sujetos (n=30) cuya edad oscilaba entre 19 y 38 anos (media 27,27 D.E. 5,25) con el Sistema Topografico Orbscan II (Orbscan, Inc., Salt Lake City, UT, USA). La media de cinco mediciones consecutivas del espesor corneal fue obtenida por dos diferentes observadores. Los resultados obtenidos por los dos observadores se compararon. Resultados: No se encontraron diferencias significativas entre los valores medios del espesor corneal de los observadores en la cornea central (p=0,749…

Weighted pointwise Hardy inequalities

2009

We introduce the concept of a visual boundary of a domain �¶ �¼ Rn and show that the weighted Hardy inequality  �¶ |u|pd�¶ �A.p  C  �¶ |�Þu|pd�¶ �A, where d�¶(x) = dist(x, �Ý�¶), holds for all u �¸ C �� 0 (�¶) with exponents �A < �A0 when the visual boundary of �¶ is sufficiently large. Here �A0 = �A0(p, n, �¶) is explicit, essentially sharp, and may even be greater than p . 1, which is the known bound for smooth domains. For instance, in the case of the usual von Koch snowflake domain the sharp bound is shown to be �A0 = p . 2 + �E, with �E = log 4/ log 3. These results are based on new pointwise Hardy inequalities.

Brominated, chlorinated and mixed brominated/chlorinated persistent organic pollutants in European eels (Anquilla anquilla) from Latvian lakes

2016

Fifty-eight European eel (Anquilla anquilla) specimens collected from five Latvian lakes were investigated for six groups of persistent organic pollutants (POPs), including polychlorinated, polybrominated and mixed bromo-chloro dibenzo-p-dioxins and dibenzofurans (PCDD/DFs, PBDD/DFs and PXDD/DFs), polychlorinated and mixed bromo-chloro biphenyls (PCBs and PXBs) and polybrominated diphenyl ethers (PBDEs). PCDD/DFs and PCBs were found to occur in the range 0.85–15.8 pg Total-WHO2005-TEQ g−1 f.w., and concentrations in most of the samples were below the maximum levels specified in European Commission Regulation (EU) No. 1259/2011. The summed concentrations of 27 PBDEs (∑PBDE) and 16 non-dioxin…

Algae utilization in assessment of the large Turawa Lake (Poland) pollution with heavy metals.

2011

This investigation was undertaken to determine the applicability of algae for the assessment of contamination level of water reservoirs with heavy metals. The alga Spirogyra sp. collected in the littoral zone of the Large Turawa Lake (artificial lake in Southern Poland) was used for the study. The concentrations of heavy metals accumulated in the alga inhabiting a flow-through water basin of the Large Turawa Lake were found to correlate with sources of these metals, such as benthic sediments and contaminated watercourses. The highest concentrations of metals were found in alga samples collected at the outlet of the lake: c (Mn) = 12330 mg/kg dry mass, c (Fe) = 15059 mg/kg d.m., c (Cu) = 47.…

Environmental history of an urban lake: a palaeolimnological study of Lake Jyväsjärvi, Finland

2003

Sedimentary diatom frustules and chironomid remains, in addition to the chemical stratigraphy of 32 elements and organic pollutants such as resin acids, PCB, DDT and its metabolites, were studied from core samples taken from Lake Jyvasjarvi in Central Finland (64° 14′ N, 25° 47′ E). The sediment profile covered over 200 years, with the oldest samples representing a period of very low human interference. The town of Jyvaskyla was established on the lake shore in 1837, and the lake received untreated municipal wastewater from the town up until, 1977. A paper mill started operations in 1872 and began discharging effluent into Lake Jyvasjarvi. In recent years this effluent loading has been redu…