Observation of the TeV gamma-ray source MGRO J1908+06 with ARGO-YBJ

The extended gamma ray source MGRO J1908+06, discovered by the Milagro air shower detector in 2007, has been observed for about 4 years by the ARGO-YBJ experiment at TeV energies, with a statistical significance of 6.2 standard deviations. The peak of the signal is found at a position consistent with the pulsar PSR J1907+0602. Parametrizing the source shape with a two-dimensional Gauss function we estimate an extension \sigma = 0.49 \pm 0.22 degrees, consistent with a previous measurement by the Cherenkov Array H.E.S.S.. The observed energy spectrum is dN/dE = 6.1 \pm 1.4 \times 10^-13 (E/4 TeV)^{-2.54 \pm 0.36} photons cm^-2 s^-1 TeV^-1, in the energy range 1-20 TeV. The measured gamma ray flux is consistent with the results of the Milagro detector, but is 2-3 times larger than the flux previously derived by H.E.S.S. at energies of a few TeV. The continuity of the Milagro and ARGO-YBJ observations and the stable excess rate observed by ARGO-YBJ along 4 years of data taking support the identification of MGRO J1908+06 as the steady powerful TeV pulsar wind nebula of PSR J1907+0602, with an integrated luminosity above 1 TeV about 1.8 times the Crab Nebula luminosity.Comment: 6 pages, accepted for pubblication by ApJ. Replaced to correct the author lis

Long-term Monitoring on Mrk 501 for Its VHE gamma Emission and a Flare in October 2011

As one of the brightest active blazars in both X-ray and very high energy $\gamma$-ray bands, Mrk 501 is very useful for physics associated with jets from AGNs. The ARGO-YBJ experiment is monitoring it for $\gamma$-rays above 0.3 TeV since November 2007. Starting from October 2011 the largest flare since 2005 is observed, which lasts to about April 2012. In this paper, a detailed analysis is reported. During the brightest $\gamma$-rays flaring episodes from October 17 to November 22, 2011, an excess of the event rate over 6 $\sigma$ is detected by ARGO-YBJ in the direction of Mrk 501, corresponding to an increase of the $\gamma$-ray flux above 1 TeV by a factor of 6.6$\pm$2.2 from its steady emission. In particular, the $\gamma$-ray flux above 8 TeV is detected with a significance better than 4 $\sigma$. Based on time-dependent synchrotron self-Compton (SSC) processes, the broad-band energy spectrum is interpreted as the emission from an electron energy distribution parameterized with a single power-law function with an exponential cutoff at its high energy end. The average spectral energy distribution for the steady emission is well described by this simple one-zone SSC model. However, the detection of $\gamma$-rays above 8 TeV during the flare challenges this model due to the hardness of the spectra. Correlations between X-rays and $\gamma$-rays are also investigated.Comment: have been accepted for publication at Ap

Different Sensitivities of Selenastrum capricornutum and Toxic Strain Microcystis aeruginosa to Exudates from Two Potamogeton Species

The sensitivities of Selenastrum capricornutum and the toxic strain Microcystis aeruginosa to exudates from Potamogeton maackianus and P. malaianus were compared using exudation experiment, and the potential allelochemicals released by these two pondweeds into surrounding water were also analyzed. The growth of S. capricornutum and M. aeruginosa was inhibited by the exudates from the two macrophytes. Compared to the control, the cell densities of S. capricornutum decreased by 42.7% and 61.9% in 2.5 and 5 g.L(-1) FW P. maackianus treatments, and the cell densities of S. capricornutum also decreased by 65.8% and 73.5% in the two biomass density treatments of P. malaianus after three clays of treatments. After 3 days' incubation in 2.5 and 5 g FW.L(-1) P. maackianus exudates, the M. aeruginosa cell densities were higher in control than in treatment. As for P. malaianus treatments, the cell densities of M. aeruginosa were reduced by 16.5 and 65.8% of the control in 2.5 and 5 g.L(-1) FW marophytes at the end of incubation period, respectively. The allelochemicals exuded from the macophytes, which inhibited both S. capricornutum and M. aeruginosa, belonged to lipophilic and moderately lipophilic compounds according to the bioassay results of exudate fractionations. By multiple comparison statistics, the results showed that P. maackianus had stronger inhibitory effects on M. aeruginsa, while S. capricornutum was more sensitive to the allelochemicals of P. malaianus. The different sensitivities of the two algae were probably caused by three alcohol compounds (1-methoxy-2-methyl-2-Propanol, 2-methyl-2-Hexanol, and 4-ethyl-2,6-dimethyl-4-Heptanol) through the GC-MS analysis of the most active exudate fractions

Spatial-temporal succession of the vegetation in Xishuangbanna, China during 1976-2010: A case study based on RS technology and implications for eco-restoration

The spatial-temporal succession of regional vegetation in Xishuangbanna, China from 1976 to 2010 was studied based on RS technology. The results showed the area fluctuation of main vegetation types in the study area during the research period. There was no great change in the total area of main vegetation, with the fluctuation area ranging from 12,579.84 to 14,698.75 km(2), averaging 13,664.48 km(2) annually, and with the fluctuation ratio between -7.94% and 7.57%. The area of natural vegetation (tropical rainforest, tropical seasonal moist forest, tropical seasonal rainforest, and tropical mountainous evergreen broad-leaved forests) increased at first and gradually decreased afterwards, and the ratio of its distribution area to the total area of main vegetation was featured with an annual decrease, especially in 2005 and 2010. Both the distribution area and ratio of artificial vegetation (Rubber plantation) to the total area of main vegetation were characterized with the tendency of a gradual increase, especially in 2005 and 2010. Thus, the establishment of artificial vegetation (Rubber plantation) not only led to the decrease in natural vegetation (3641.16 km(2)) but also covered 343.66 km(2) of lands for other uses. The results also showed the distribution succession of main vegetation types in the study area during the research period. In the later research period (after 1999), compared with the early research period (before 1999), the distribution range of natural vegetation was characterized with a certain decrease in the following aspects as at different altitudes (1400m), and on different slopes (0-5 degrees, 5-8 degrees, 8-15 degrees, 15-25 degrees, 25-35 degrees, and >35 degrees). By contrast, the artificial vegetation was just the opposite whose distribution range was characterized with a tendency of a rapid growth at different altitudes, and on different slopes. It indicated that the establishment of artificial vegetation had broken the original ecological pattern in Xishuangbanna, which would bring direct threats to the regional ecological security and environment healthy development, thus countermeasures were urgent to be taken in order to prevent it from worsening. (C) 2014 Elsevier B.V. All rights reserved.The spatial-temporal succession of regional vegetation in Xishuangbanna, China from 1976 to 2010 was studied based on RS technology. The results showed the area fluctuation of main vegetation types in the study area during the research period. There was no great change in the total area of main vegetation, with the fluctuation area ranging from 12,579.84 to 14,698.75 km(2), averaging 13,664.48 km(2) annually, and with the fluctuation ratio between -7.94% and 7.57%. The area of natural vegetation (tropical rainforest, tropical seasonal moist forest, tropical seasonal rainforest, and tropical mountainous evergreen broad-leaved forests) increased at first and gradually decreased afterwards, and the ratio of its distribution area to the total area of main vegetation was featured with an annual decrease, especially in 2005 and 2010. Both the distribution area and ratio of artificial vegetation (Rubber plantation) to the total area of main vegetation were characterized with the tendency of a gradual increase, especially in 2005 and 2010. Thus, the establishment of artificial vegetation (Rubber plantation) not only led to the decrease in natural vegetation (3641.16 km(2)) but also covered 343.66 km(2) of lands for other uses. The results also showed the distribution succession of main vegetation types in the study area during the research period. In the later research period (after 1999), compared with the early research period (before 1999), the distribution range of natural vegetation was characterized with a certain decrease in the following aspects as at different altitudes (1400m), and on different slopes (0-5 degrees, 5-8 degrees, 8-15 degrees, 15-25 degrees, 25-35 degrees, and >35 degrees). By contrast, the artificial vegetation was just the opposite whose distribution range was characterized with a tendency of a rapid growth at different altitudes, and on different slopes. It indicated that the establishment of artificial vegetation had broken the original ecological pattern in Xishuangbanna, which would bring direct threats to the regional ecological security and environment healthy development, thus countermeasures were urgent to be taken in order to prevent it from worsening. (C) 2014 Elsevier B.V. All rights reserved

Changes in the ΔΨ_m of macrophage.

<p>Peritoneal hamster macrophages (2×10⁶ cells/mL) were cultured in the presence of LQB-118 for 48 h at 37°C/5%CO₂. The cells were incubated for 10 min with JC-1 and analysed fluorometrically. Results are presented as means ± standard error; <i>n</i> = 3. *<i>P</i><0.05; **<i>P</i><0.01.</p

Activity of LQB-118 on golden hamsters infected with <i>L. braziliensis</i>.

<p>Golden hamsters (5/group) infected with <i>L. braziliensis</i> (10⁷) were treated on the seventh day of infection with LQB-118 intralesional (26 µg/kg/day) three times/week or orally (4,3 mg/kg/day) five times/week during eight weeks. Controls were untreated, treated with intralesional DMSO three times/week or Glucantime five times/week by intraperitoneal route. <b>A</b>) Lesion thickness was measured for nine weeks. The arrow indicates the start of treatment. Mean ± SD, # P<0.002 (in relation to untreated group). <b>*</b> p<0.001 (in relation to intralesional DMSO group); <b>B</b>) Intradermal reaction at <i>L. braziliensis</i> antigen was evaluated on the contralateral foot pad on eight week of infection. The swelling was measured 48 h later in the antigen-injected footpads. * p<0,04; ** p<0,01. Each point represents one animal and the horizontal bar indicates the mean. <b>C</b>) Parasite burden was assessment by limiting dilution at the end of treatment. *** p<0,001. il, intralesional/subcutaneous; ip, intraperitoneal.</p

Synthesized Attributes of Water Use by Regional Vegetation: A Key to Cognition of "Water Pump" Viewpoint

Recently, the frequent seasonal drought in Southwest China has brought considerable concerns and continuous heated arguments on the "water pump" viewpoint (i.e., the water demand from Hevea spp. and Eucalyptus spp. can be treated as a water pump) once again. However, such viewpoint just focused on water consumption from vegetation transpiration and its ecoenvironment impacts, which had not considered other attributes of vegetation, namely, water saving and drought resistance, and hydrological regulation (water conservation) into consideration. Thus, in this paper, the synthesized attributes of regional vegetation water use had been mainly discussed. The results showed that the study on such aspects as the characters of water consumption from vegetation transpiration, the potential of water saving and drought resistance, and the effects of hydrological regulation in Southwest China lagged far behind, let alone the report on synthesized attributes of water utilization with the organic combination of the three aspects above or the paralleled analysis. Accordingly, in this paper, the study on the synthesized attributes of water use by regional vegetation in Southwest China was suggested, and the objectives of such a special study were clarified, targeting the following aspects: (i) characters of water consumption from transpiration of regional typical artificial vegetation; (ii) potential of water saving and drought resistance of regional typical artificial vegetation; (iii) effects of hydrological regulation of regional typical artificial vegetation; (iv) synthesized attributes of water use by regional typical artificial vegetation. It is expected to provide a new idea for the scientific assessment on the regional vegetation ecoenvironment effects and theoretical guidance for the regional vegetation reconstruction and ecological restoration.Recently, the frequent seasonal drought in Southwest China has brought considerable concerns and continuous heated arguments on the "water pump" viewpoint (i.e., the water demand from Hevea spp. and Eucalyptus spp. can be treated as a water pump) once again. However, such viewpoint just focused on water consumption from vegetation transpiration and its ecoenvironment impacts, which had not considered other attributes of vegetation, namely, water saving and drought resistance, and hydrological regulation (water conservation) into consideration. Thus, in this paper, the synthesized attributes of regional vegetation water use had been mainly discussed. The results showed that the study on such aspects as the characters of water consumption from vegetation transpiration, the potential of water saving and drought resistance, and the effects of hydrological regulation in Southwest China lagged far behind, let alone the report on synthesized attributes of water utilization with the organic combination of the three aspects above or the paralleled analysis. Accordingly, in this paper, the study on the synthesized attributes of water use by regional vegetation in Southwest China was suggested, and the objectives of such a special study were clarified, targeting the following aspects: (i) characters of water consumption from transpiration of regional typical artificial vegetation; (ii) potential of water saving and drought resistance of regional typical artificial vegetation; (iii) effects of hydrological regulation of regional typical artificial vegetation; (iv) synthesized attributes of water use by regional typical artificial vegetation. It is expected to provide a new idea for the scientific assessment on the regional vegetation ecoenvironment effects and theoretical guidance for the regional vegetation reconstruction and ecological restoration

Potential effects of climate change on geographic distribution of the Tertiary relict tree species Davidia involucrata in China

This study, using species distribution modeling (involving a new approach that allows for uncertainty), predicts the distribution of climatically suitable areas prevailing during the mid-Holocene, the Last Glacial Maximum (LGM), and at present, and estimates the potential formation of new habitats in 2070 of the endangered and rare Tertiary relict tree Davidia involucrata Baill. The results regarding the mid-Holocene and the LGM demonstrate that south-central and southwestern China have been long-term stable refugia, and that the current distribution is limited to the prehistoric refugia. Given future distribution under six possible climate scenarios, only some parts of the current range of D. involucrata in the mid-high mountains of south-central and southwestern China would be maintained, while some shift west into higher mountains would occur. Our results show that the predicted suitable area offering high probability (0.5-1) accounts for an average of only 29.2% among the models predicted for the future (2070), making D. involucrata highly vulnerable. We assess and propose priority protected areas in light of climate change. The information provided will also be relevant in planning conservation of other paleoendemic species having ecological traits and distribution ranges comparable to those of D. involucrata

Evaluation of LQB118 inducing apoptosis on <i>L. braziliensis</i> – A) and B) Phosphatidylserine exposure on promastigotes.

<p>Promastigotes were incubated with 3,5 or 20 µM LQB118 to 24 or 48 h/28°C and then stained with Annexin V-FITC+propidium iodide and analyzed by flow cytometer. Controls were promastigotes incubated with 60 µM Miltefosine or the culture medium supplemented with 20% fetal bovine serum. In <b>A</b> only treatment at 48 h and in <b>B</b> quantitative evaluation of cells stained with annexin V-FITC at 24 and 48 h. (mean ± SD, n = 3). * P<0.05 ** P<0.01. <b>C) ROS generation and D) impairment of ATP production in LQB-118-treated promastigotes</b>. Promastigotes of <i>L. braziliensis</i> were incubated for 48 h in the presence of LQB-118 in Schneider's insect medium plus 10% HIFCS. <b>A</b>) ROS generation was quantified using H₂DCFDA, <b>B</b>) Cellular ATP concentration was measured by bioluminescence assay. Results are presented as means ± standard error; <i>n</i> = 3. *<i>P</i><0.05; **<i>P</i><0.01. <b>E) </b><b><i>In situ</i></b><b> DNA fragmentation of intracellular amastigote</b>. Infected monolayers of hamsters peritoneal macrophages were treated with the indicated concentrations of LQB118 for 48 h. Monolayers were labeled using TUNEL and observated using fluorescence microscopy. Highlight the cells in 400× magnification. Legend Arrows indicate intracellular amastigotes, N – Macrophage nucleus.</p