38 research outputs found
Дуготрајне промене трофије у бугарско-румунском делу Дунава и околних мочвара на територији бугарске током њене рестаурације
Based mainly on literature data and results of the monitoring program
of the Bulgarian Ministry of Environment and Water, the long-term changes of
nutrients (nitrogen and phosphorus), suspended solids and chlorophyll-concentrations
in the Bulgarian–Romanian section of the Lower Danube during the period 1950–2014
were studied. The addition of more recent data from years 2008–2014 revealed stable
lowering with values of PO4
3- concentrations close to those reported in the earliest
1962–1965 interval. The calculated load of dissolved inorganic nitrogen (DIN) showed
a continuous but not significant decrease, while the PO4-P load dropped at the end of
the 1950–2014 period to the values of its beginning. These changes of nitrogen and
phosphorus led to a substantial shift of the N P-1 ratio towards phosphorus limitation
of phytoplankton growth in the 2008–2014 period.
The second part of the paper presented and analyzed the process of restoration of
wetlands on the example of Srebarna Lake. The primary goal of this restoration was
to sustain the valuable biodiversity supported by this lake, but as a wetland it should
provide also most other services, one of which was nutrient removal. The monitoring
of lake restoration started in 1990 and lasted with gaps until 2015. The main force
driving the changes of other lake characteristics was the lake water level. Thus the lake
water level correlated positively with water column transparency and negatively with
chlorophyll-a, phytoplankton biovolume and the share of blue-greens from it. Since
1994 only one canal connected the lake with the Danube River, which seemed to be the
reason for the limited success of the wetland restoration.На основу, пре свега, података из литературе и резултата програма
праћења Министарства за животну средину и воде Бугарске, проучене су
дугорочне промене нутријената (азота и фосфора), суспендованих чврстих
честица и концентрација хлорофила у бугарско-румунском делу доњег тока
Дунава током периода 1950–2014. године. Анализом и скоријих података
за године 2008–2014, регистровано је стабилно снижавање са вредностима
концентрација PO4
3- близу онима које су забележене у најранијем интервалу
– у годинама 1962–1965. Израчунатo оптерећење раствореног неорганског
азота (DIN) показало је стално, али не значајно смањење, док је оптерећење
PO4-P пало крајем периода 1950–2014. на вредности са почетка. Те промене
азота и фосфора довеле су до значајне промене показатеља N P-1 ка фосфорном ограничењу раста фитопланктона у периоду 2008–2014. године.
У другом делу рада представљен је и анализиран процес санације мочварних подручја на примеру језера Сребарна. Главни циљ санације јесте
одржавање вредног биодиверзитета који подржава то језеро; међутим, као
мочварно подручје, оно треба да пружи и већину других услуга, које укључују, између осталог, уклањање нутријената. Праћење санације језера почело је 1990. и с прекидима трајало до 2015. године. Главни покретач промена
других карактеристика језера био је ниво воде у језеру. Постојала је позитивна корелација између нивоа воде у језеру и прозирности воденог стуба
и негативна корелација са хлорофилом а, биозапремином фитопланктона
и уделом њихових плавозелених облика. Од 1994. године, само један канал
повезује језеро са Дунавом, што вероватно представља разлог ограниченог
успеха санације мочварног подручја.8. Конференција академија подунавске региј
Gene expression of PMP22 is an independent prognostic factor for disease-free and overall survival in breast cancer patients
<p>Abstract</p> <p>Background</p> <p>Gene expression of peripheral myelin protein 22 (<it>PMP22</it>) and the epithelial membrane proteins (<it>EMPs</it>) was found to be differentially expressed in invasive and non-invasive breast cell lines in a previous study. We want to evaluate the prognostic impact of the expression of these genes on breast cancer.</p> <p>Methods</p> <p>In a retrospective multicenter study, gene expression of <it>PMP22 </it>and the <it>EMPs </it>was measured in 249 primary breast tumors by real-time PCR. Results were statistically analyzed together with clinical data.</p> <p>Results</p> <p>In univariable Cox regression analyses PMP22 and the EMPs were not associated with disease-free survival or tumor-related mortality. However, multivariable Cox regression revealed that patients with higher than median <it>PMP22 </it>gene expression have a 3.47 times higher risk to die of cancer compared to patients with equal values on clinical covariables but lower <it>PMP22 </it>expression. They also have a 1.77 times higher risk to relapse than those with lower <it>PMP22 </it>expression. The proportion of explained variation in overall survival due to <it>PMP22 </it>gene expression was 6.5% and thus PMP22 contributes equally to prognosis of overall survival as nodal status and estrogen receptor status. Cross validation demonstrates that 5-years survival rates can be refined by incorporating <it>PMP22 </it>into the prediction model.</p> <p>Conclusions</p> <p><it>PMP22 </it>gene expression is a novel independent prognostic factor for disease-free survival and overall survival for breast cancer patients. Including it into a model with established prognostic factors will increase the accuracy of prognosis.</p
Carbon dioxide fluxes increase from day to night across European streams
Globally, inland waters emit over 2 Pg of carbon per year as carbon dioxide, of which the majority originates from streams and rivers. Despite the global significance of fluvial carbon dioxide emissions, little is known about their diel dynamics. Here we present a large-scale assessment of day- and night-time carbon dioxide fluxes at the water-air interface across 34 European streams. We directly measured fluxes four times between October 2016 and July 2017 using drifting chambers. Median fluxes are 1.4 and 2.1 mmol m−2 h−1 at midday and midnight, respectively, with night fluxes exceeding those during the day by 39%. We attribute diel carbon dioxide flux variability mainly to changes in the water partial pressure of carbon dioxide. However, no consistent drivers could be identified across sites. Our findings highlight widespread day-night changes in fluvial carbon dioxide fluxes and suggest that the time of day greatly influences measured carbon dioxide fluxes across European streams
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The recovery of European freshwater biodiversity has come to a halt
Owing to a long history of anthropogenic pressures, freshwater ecosystems are among the most vulnerable to biodiversity loss. Mitigation measures, including wastewater treatment and hydromorphological restoration, have aimed to improve environmental quality and foster the recovery of freshwater biodiversity. Here, using 1,816 time series of freshwater invertebrate communities collected across 22 European countries between 1968 and 2020, we quantified temporal trends in taxonomic and functional diversity and their responses to environmental pressures and gradients. We observed overall increases in taxon richness (0.73% per year), functional richness (2.4% per year) and abundance (1.17% per year). However, these increases primarily occurred before the 2010s, and have since plateaued. Freshwater communities downstream of dams, urban areas and cropland were less likely to experience recovery. Communities at sites with faster rates of warming had fewer gains in taxon richness, functional richness and abundance. Although biodiversity gains in the 1990s and 2000s probably reflect the effectiveness of water-quality improvements and restoration projects, the decelerating trajectory in the 2010s suggests that the current measures offer diminishing returns. Given new and persistent pressures on freshwater ecosystems, including emerging pollutants, climate change and the spread of invasive species, we call for additional mitigation to revive the recovery of freshwater biodiversity