210 research outputs found
Variable X-ray absorption in the mini-BAL QSO PG 1126-041
X-ray studies of active galactic nuclei (AGN) with powerful nuclear winds are
important for constraining the physics of the inner accretion/ejection flow
around supermassive black holes (SMBHs) and for understanding the impact of
such winds on the AGN environment. Our main scientific goal is to constrain the
properties of the circum-nuclear matter close to the SMBH in the mini-broad
absorption line quasar (mini-BAL QSO) PG 1126-041 using a multi-epoch
observational campaign with XMM-Newton. We performed temporally resolved X-ray
spectroscopy and simultaneous UV and X-ray photometry on the most complete set
of observations and on the deepest X-ray exposure of a mini-BAL QSO ever. We
found complex X-ray spectral variability on time scales of both months and
hours, which is best reproduced by means of variable massive ionized absorbers
along the line of sight. As a consequence, the observed optical-to-X-ray
spectral index is found to be variable with time. In the highest
signal-to-noise observation we detected highly ionized X-ray absorbing material
outflowing much faster (v ~ 16500 km/s) than the UV absorbing one (v ~ 5000
km/s). This highly ionized absorber is found to be variable on very short (a
few kiloseconds) time scales. Our findings are qualitatively consistent with
line-driven accretion disk winds scenarios. Our observations have opened the
time-resolved X-ray spectral analysis field for mini-BAL QSOs. Only with future
deep studies will we be able to map the dynamics of the inner flow and
understand the physics of AGN winds and their impact on the environment.Comment: Replaced to match the published versio
Editorial: Biogenic Reefs at Risk: Facing Globally Widespread Local Threats and Their Interaction With Climate Change
Biogenic reefs are secondary marine substrates, also referred to as bioconstructions or bioherms, made by autogenic ecosystem engineers (sensu, Jones et al., 1994) that provide habitats for various species. Their ecological role goes far beyond simple physical effects because they can modulate many resources and interactions between species inhabiting the reefs. Marine bioconstructions involve a variety of fragile three-dimensional habitats, from shallow water coral reefs to mesophotic coralligenous concretions, hosting rich, and diverse benthic assemblages (Cocito, 2004; Ingrosso et al., 2018; Cerrano et al., 2019). Biogenic reefs can be found from the intertidal to the deep sea; some are ephemeral and last a few years, while others remain active for millennia. The main framework builders are able to form bioconstructions at different latitudes, from tropical to polar zones, and include films of cyanobacteria and diatoms, calcareous rhodophytes, sponges, hermatypic symbiotic and aposymbiotic corals, polychaetes as serpulids and sabellariids, mollusks like vermetids, oysters and mussels, and bryozoans
Opadanje stoka školjkaša Ruditapes philippinarum u uvalama sjevernog Jadrana:anketa o ekološkim i društveno-ekonomskim aspektima
The Manila clam, Ruditapes philippinarum, introduced in the Venice lagoons in 1983 and rapidly spread to the nearby coastal lagoons represents one of the most important commercially-
exploited resources of this area. Abundance, size-class and biomass distribution of the wild population living in the Pialassa Baiona lagoon were assessed and related to the hydrological
and sediment characteristics. Despite the lagoon being affected by eutrophication, chemical and thermal pollution, the clams were harvested by about thirty professional fishermen until 2003. The
commercially available stock was estimated at 36.8 10 3 kg in July 2002, 29.3 10 3 kg in April 2003, and 10.3 10 3 kg in October 2003. Stock estimations and observed mortality were in good accordance
with the fishermen data. The decline of the available stock could be due to both overfishing and the extraordinary summer heat wave occurred in 2003, which may have reduced larval recruitment and
increased the mortality. Overall, the juvenile recruitment appeared insufficient to annually restore the natural stock. Although the national and regional high relevance of clams market, local harvesting of wild populations appeared marginal and inadequate to support a remunerative commercial activity, due to the variability and unpredictability of the annual yield and the lack of a sustainable management based on a production chain’s approach.Školjkaš Ruditapes philippinarum, zabilježena u Venecijanskoj laguni 1983. godine gdje se brzo proširila i na obližnje obalne lagune te predstavlja jedan od najvažnijih komercijalno iskorištenih resursa ovog područja. U laguni Pialassa Baiona procjenjene su abundancija, veličina klase i raspodjela biomase prirodnih populacija u odnosu na hidrološke i sedimentne karakteristike. Unatoč tome što je laguna bila pogođena eutrofikacijom, kemijskim i toplinskim zagađenjima, oko trideset profesionalnih ribara sakupljalo je školjke do 2003. godine. Dostupne zalihe stoka komercijalnih vrsta procijenjene su na 36,8 10,
3kg u srpnju 2002. godine, zatim na 29.3 10 3kg u travnju 2003. godine i na 10,3 10 3 kg u listopadu 2003. godine. Procjene zaliha i smrtnosti bile su u skladu s podacima ribara. Pad raspoloživih zaliha mogao bi biti posljedica prekomjernog izlova i izvanrednog ljetnoga toplinskog vala koji se dogodio 2003. godine, što je utjecalo na smanjenje novačenja ličinki i povećanje smrtnosti. Sveukupno gledano novačenje juvenilnih primjeraka nije bilo dovoljno za
godišnje obnavljanje prirodnih zaliha. Iako je na nacionalnoj i regionalnoj razini velika važnost tržišta školjki, lokalna berba divljih populacija jest marginalna i neadekvatna za podupiranje profitabilne komercijalne aktivnosti, zbog varijabilnosti i nepredvidljivosti godišnjeg prinosa i nedostatka održivog upravljanja temeljenog na pristupu proizvodnog lanca
Chemical and biological indicators of water quality in three agricultural watersheds of the Po valley, Italy
open9noAgriculture has both direct and indirect effects on quality of surface water and is one of the key activities causing water quality degradation. Its environmental impact can be evaluated by the determination of indicators of the quality of water bodies that collect drainage and runoff waters from agricultural watersheds. For this research, the water quality draining from three watersheds, totally or partially cultivated, all within the Po river valley (Italy), was determined, using chemical indicators (N-NO3 and N-NH4 concentration, N balance), trophic status (chlorophyll-a concentration) and benthic population indexes. Together, they should provide an overview of the water status, which is supposed to be strictly related to the land use and the management. Results show that the chemical parameters are well related to land use and farming management: intensive agricultural activity leads to high N-NO3 concentration in water and N surplus and vice versa. The chlorophyll-a concentration follows the same trend, being linked to nitrogen loads and land use. Not always there is accordance between chemical and biological indicators: no direct correspondence is evident between the N-NO3 concentration in waters and benthic community. Its presence and abundance seems to be mostly correlated with the geomorphology, hydrology, riparian strips, etc. of the habitat than to the land use. Only the integration of chemical and biological parameters allows a correct understanding of the state of health of water body and benthic communities.openPIERI L.; VENTURA F.; VENTURA M.; TAGLIAVINI M.; PONTI M.; PISTOCCHI R.; ALBERTAZZI S.; VIGNUDELLI M.; ROSSI PISA P.PIERI L.; VENTURA F.; VENTURA M.; TAGLIAVINI M.; PONTI M.; PISTOCCHI R.; ALBERTAZZI S.; VIGNUDELLI M.; ROSSI PISA P
Baseline reef health surveys at Bangka Island (North Sulawesi, Indonesia) reveal new threats
Worldwide coral reef decline appears to be accompanied by an increase in the spread of hard coral diseases. However, whether this is the result of increased direct and indirect human disturbances and/or an increase in natural stresses remains poorly understood. The provision of baseline surveys for monitoring coral health status lays the foundations to assess the effects of any such anthropogenic and/or natural effects on reefs. Therefore, the objectives of this present study were to provide a coral health baseline in a poorly studied area, and to investigate possible correlations between coral health and the level of anthropogenic and natural disturbances. During the survey period, we recorded 20 different types of coral diseases and other compromised health statuses. The most abundant were cases of coral bleaching, followed by skeletal deformations caused by pyrgomatid barnacles, damage caused by fish bites, general pigmentation response and galls caused by cryptochirid crabs. Instances of colonies affected by skeletal eroding bands, and sedimentation damage increased in correlation to the level of bio-chemical disturbance and/or proximity to villages. Moreover, galls caused by cryptochirid crabs appeared more abundant at sites affected by blast fishing and close to a newly opened metal mine. Interestingly, in the investigated area the percentage of corals showing signs of ‘common’ diseases such as black band disease, brown band disease, white syndrome and skeletal eroding band disease were relatively low. Nevertheless, the relatively high occurrence of less common signs of compromised coral-related reef health, including the aggressive overgrowth by sponges, deserves further investigation. Although diseases appear relatively low at the current time, this area may be at the tipping point and an increase in activities such as mining may irredeemably compromise reef health.This research was partially funded by Coral Eye, which hosted FF and covered all field expenses. The non-profit organization Reef Check Italia Onlus sustained the cost for open source publication. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript
The Reef Check Mediterranean Underwater Coastal Environment Monitoring Protocol
Since 2001, trained snorkelers, freedivers, and scuba diver volunteers (collectively called EcoDivers) have been recording data on the distribution, abundance, and bathymetric range of 43 selected key marine species along the Mediterranean Sea coasts using the Reef Check Mediterranean Underwater Coastal Environment Monitoring (RCMed U-CEM) protocol. The taxa, including algae, invertebrates, and fishes, were selected by a combination of criteria, including ease of identification and being a key indicator of shifts in the Mediterranean subtidal habitats due to local pressures and climate change. The presence and abundance of gas bubbles leaching from the seabed are also recorded. The dataset collected using the RCMed U-CEM protocol is openly accessible across different platforms and allows for various uses. It has proven to be useful for several purposes, such as monitoring the ecological status of Mediterranean coastal environments, assessing the effects of human impacts and management interventions, as well as complementing scientific papers on species distribution and abundance, distribution modeling, and historical series. Also, volunteers\u2019 commitment promotes marine stewardship and environmental awareness in marine conservation. Here, we describe the RCMed U-CEM protocol, from training volunteers to recording, delivery, and sharing data, including the quality assurance and control (QA/QC) procedures
Spring composition of the macroalgal vegetation of a small offshore island in the north-western Mediterranean (Gallinara Island, Ligurian Sea)
Gallinara Island, a small island located 1.5 km off the shore of Liguria (Italy, north-western Mediterranean Sea) was included in a list of proposed Marine Protected Areas (MPA) in the early 90s. Since then, its benthic assemblages have been studied in detail and the main macrophytic communities have been mapped. A detailed assessment of its benthic macroalgal flora, however, has never been made. Gallinara was visited in the course of 5 consecutive years and its macroalgal flora was studied based on collections made by snorkelling and SCUBA diving. Overall, 141 macroalgal taxa were collected and identified (23 Chlorophyta, 94 Rhodophyta, 24 Ochrophyta); 91 of them represent new records for the island. One of the most notable new records is the non-indigenous red alga Womersleyella setacea, previously unreported from the island and widely distributed, particularly on the south-eastern shore. Observations made in the course of the surveys confirm the rarefaction of some large-sized brown algae (particularly Sargassum vulgare) but indicate also that others previously reported as rare (Cystoseira compressa, Dictyopteris polypodioides) are still common on the island
Sensitivity to cisplatin in primary cell lines derived from human glioma correlates with levels of EGR-1 expression
<p>Abstract</p> <p>Background</p> <p>Less than 30% of malignant gliomas respond to adjuvant chemotherapy. Here, we have asked whether variations in the constitutive expression of early-growth response factor 1 (EGR-1) predicted acute cytotoxicity and clonogenic cell death <it>in vitro</it>, induced by six different chemotherapics.</p> <p>Materials and methods</p> <p>Cytotoxicity assays were performed on cells derived from fresh tumor explants of 18 human cases of malignant glioma. In addition to EGR-1, tumor cultures were investigated for genetic alterations and the expression of cancer regulating factors, related to the p53 pathway.</p> <p>Results</p> <p>We found that sensitivity to cisplatin correlates significantly with levels of EGR-1 expression in tumors with wild-type <it>p53/INK4a/p16 </it>status.</p> <p>Conclusion</p> <p>Increased knowledge of the mechanisms regulating EGR-1 expression in wild-type <it>p53/INK4a/p16 </it>cases of glioma may help in the design of new chemotherapeutic strategies for these tumors.</p
Mass mortality hits gorgonian forests at Montecristo Island.
Mediterranean gorgonian forests are species-rich habitats, and like many other marine habitats they are threatened by anthropogenic disturbances and mass mortality events. These mortality events have often been linked to anomalies in the temperature profiles of the Mediterranean region. On 5 September 2017, colonies of the gorgonians Eunicella singularis and Eunicella cavolini exhibited rapid tissue loss, down to a depth of 30 m along the steep cliffs of Montecristo Island, Tuscan Archipelago National Park, Tyrrhenian Sea, Italy. Interestingly, Montecristo has previously been identified as a reference site for the ecological quality assessment of the western Mediterranean benthic assemblages on rocky bottoms. The observed mortality event occurred during a period of increased sea temperature. By utilising a combination of high-resolution oceanographic analysis, forecast models and citizen science initiatives, we propose that an early warning system for the concomitance of heat waves and mortality events can be put in place. A temperature-based coral disease surveillance tool could then be established for the entire Mediterranean Sea. Such a tool would allow for the timely study of mass mortality phenomena and the implementation of prompt mitigation and/or restoration initiatives. Finally, this specific mortality event, in a Marine Protected Area, offers a unique opportunity to monitor and assess the resilience of gorgonian populations and associated benthic assemblages in the absence of other, more directly, anthropogenic disturbances such as pollution and land runoff.N/
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