2,264 research outputs found
Winter temperature predicts prolonged diapause in pine processionary moth species across their geographic range
Prolonged diapause occurs in a number of insects and is interpreted as a way to evade
adverse conditions. The winter pine processionary moths (Thaumetopoea pityocampa
and Th. wilkinsoni) are important pests of pines and cedars in the Mediterranean region.
They are typically univoltine, with larvae feeding across the winter, pupating in spring
in the soil and emerging as adults in summer. Pupae may, however, enter a prolonged
diapause with adults emerging one or more years later. We tested the effect of variation
in winter temperature on the incidence of prolonged diapause, using a total of 64
individual datasets related to insect cohorts over the period 1964 2015 for 36 sites in
seven countries, covering most of the geographic range of both species. We found high
variation in prolonged diapause incidence over their ranges. At both lower and upper
ends of the thermal range in winter, prolonged diapause tended to be higher than at
intermediate temperatures. Prolonged diapause may represent a risk-spreading strategy
to mitigate climate uncertainty, although it may increase individual mortality because of
a longer exposure to mortality factors such as predation, parasitism, diseases or energy
depletion. Climate change, and in particular the increase of winter temperature, may
reduce the incidence of prolonged diapause in colder regions whereas it may increase
it in warmer ones, with consequences for population dynamics.Work supported by Fondazione Cassa di Risparmio di Padova e Rovigo to Md H.R.
Salman, University of Padova to Myron P. Zalucki and Folco Giomi, Spanish Ministry
of the Environment (PROPINOL PN22/2008 and CONSOLIDER-MONTES CSD2008-
00040) to José A. Hodar, DIAMETABO project of the INRA EFPA department to Mathieu
Laparie, European Union's Horizon 2020 research and innovation programme under
grant agreement N. 771271 HOMED (Holistic Management of Emerging forest pests and
Diseases) to Andrea Battisti
Mice lacking NF-κB1 exhibit marked DNA damage responses and more severe gastric pathology in response to intraperitoneal tamoxifen administration
Tamoxifen (TAM) has recently been shown to cause acute gastric atrophy and metaplasia in mice. We have previously demonstrated that the outcome of Helicobacter felis infection, which induces similar gastric lesions in mice, is altered by deletion of specific NF-κB subunits. Nfkb1-/- mice developed more severe gastric atrophy than wild-type (WT) mice 6 weeks after H. felis infection. In contrast, Nfkb2-/- mice were protected from this pathology. We therefore hypothesized that gastric lesions induced by TAM may be similarly regulated by signaling via NF-κB subunits. Groups of five female C57BL/6 (WT), Nfkb1-/-, Nfkb2-/- and c-Rel-/- mice were administered 150 mg/kg TAM by IP injection. Seventy-two hours later, gastric corpus tissues were taken for quantitative histological assessment. In addition, groups of six female WT and Nfkb1-/- mice were exposed to 12 Gy γ-irradiation. Gastric epithelial apoptosis was quantified 6 and 48 h after irradiation. TAM induced gastric epithelial lesions in all strains of mice, but this was more severe in Nfkb1-/- mice than in WT mice. Nfkb1-/- mice exhibited more severe parietal cell loss than WT mice, had increased gastric epithelial expression of Ki67 and had an exaggerated gastric epithelial DNA damage response as quantified by γH2AX. To investigate whether the difference in gastric epithelial DNA damage response of Nfkb1-/- mice was unique to TAM-induced DNA damage or a generic consequence of DNA damage, we also assessed gastric epithelial apoptosis following γ-irradiation. Six hours after γ-irradiation, gastric epithelial apoptosis was increased in the gastric corpus and antrum of Nfkb1-/- mice. NF-κB1-mediated signaling regulates the development of gastric mucosal pathology following TAM administration. This is associated with an exaggerated gastric epithelial DNA damage response. This aberrant response appears to reflect a more generic sensitization of the gastric mucosa of Nfkb1-/- mice to DNA damage
Multi-stage generation of extreme ultraviolet dispersive waves by tapering gas-filled hollow-core anti-resonant fibers
In this work, we numerically investigate an experimentally feasible design of
a tapered Ne-filled hollow-core anti-resonant fiber and we report the
generation of multiple dispersive waves (DWs) in the range 90-120 nm, well into
the extreme ultraviolet (UV) region. The simulations assume an 800 nm pump
pulse with 30 fs 10 J pulse energy, launched into a 9 bar Ne-filled fiber
with m initial core diameter that is then tapered to a m core
diameter. The simulations were performed using a new model that provides a
realistic description of both loss and dispersion of the resonant and
anti-resonant spectral bands of the fiber, and also importantly includes the
material loss of silica in the UV. We show that by first generating solitons
that emit DWs in the far-UV region in the pre-taper section, optimization of
the following taper structure can allow re-collision with the solitons and
further up-conversion of the far-UV DWs to the extreme-UV with energies up to
190 nJ in the 90-120 nm range. This process provides a new way to generate
light in the extreme-UV spectral range using relatively low gas pressure
Nephroprotective Effect of the Virgin Olive Oil Polyphenol Hydroxytyrosol in Type 1-like Experimental Diabetes Mellitus: Relationships with Its Antioxidant Effect
The aim of this study was to determine whether hydroxytyrosol administration prevented kidney damage in an experimental model of type 1 diabetes mellitus in rats. Hydroxytyrosol was administered to streptozotocin-diabetic rats: 1 and 5 mg/kg/day p.o. for two months. After hydroxytyrosol administration, proteinuria was significantly reduced (67–73%), calculated creatinine clearance was significantly increased (26–38%), and the glomerular volume and glomerulosclerosis index were decreased (20–30%). Hydroxytyrosol reduced oxidative and nitrosative stress variables and thromboxane metabolite production. Statistical correlations were found between biochemical and kidney function variables. Oral administration of 1 and 5 mg/kg/day of hydroxytyrosol produced an antioxidant and nephroprotective effect in an experimental model of type 1-like diabetes mellitus. The nephroprotective effect was significantly associated with the systemic and renal antioxidant action of hydroxytyrosol, which also influenced eicosanoid production
Disability related to chronic low back pain: prevalence abd associated factors
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Disability related to chronic low back pain (CLBP) is a complex and multidimensional phenomenon. The aim of the study was to identify the prevalence of disability and factors associated with disability outcome in 177 CLBP adults. Respondents were recruited from three health care service centers and answered questions from: Demographic Identification Form, Oswestry Disability Index, Chronic Pain Self-efficacy Scale, Tampa Scale Kinesiophobia, Beck Depression Inventory, and the Revised Piper Fatigue Scale. The prevalence of disability among the respondents was 65% (95% CI: 57.5 - 72.0), and disability was moderate to severe in 80.7% of them. The multiple regression model identified three factors as independently associated with disability: work situation, low self-efficacy and depression. The factors identified to be associated with disability are modifiable. Interventions such as work relocation, depression treatment and re-conceptualization of self-efficacy may have an important impact in preventing and reducing disability in chronic low back pain patients.46SI1623Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq
Noise performance and long-term stability of near- and mid-IR gas-filled fiber Raman lasers
In this letter, the characteristics of noise and long-term stability of near-
and mid-infrared (near-IR and mid-IR) gas-filled fiber Raman lasers have been
investigated for the first time. The results reveal that an increase in Raman
pulse energy is associated with a decrease in noise, and that the relative
pulse peak intensity noise (RIN) is always lower than the relative pulse energy
noise (REN). We also demonstrate that long-term drift of the pulse energy and
peak power are directly linked with the high amount of heat release during the
Raman Stokes generation. The demonstrated noise and long-term stability
performance provide necessary references for potential spectroscopic
applications as well as further improvements of the emerging mid-IR gas-filled
hollow-core fiber (HCF) Raman laser technology
Multi-wavelength high energy gas-filled fiber Raman laser spanning from 1.53 um to 2.4 um
In this work, we present a high pulse energy multi-wavelength Raman laser
spanning from 1.53 um up to 2.4 um by employing the cascaded rotational
stimulated Raman scattering (SRS) effect in a 5-m hydrogen (H2) -filled nested
anti-resonant fiber (NARF), pumped by a linearly polarized Er/Yb fiber laser
with a peak power of ~13 kW and pulse duration of ~7 ns in the C-band. The
developed Raman laser has distinct lines at 1683 nm, 1868 nm, 2100 nm, and 2400
nm, with pulse energies as high as 18.25 uJ, 14.4 uJ, 14.1 uJ, and 8.2 uJ,
respectively. We demonstrate how the energy in the Raman lines can be
controlled by tuning the H2 pressure from 1 bar to 20 ba
Noise and spectral stability of deep-UV gas-filled fiber-based supercontinuum sources driven by ultrafast mid-IR pulses
Deep-UV (DUV) supercontinuum (SC) sources based on gas-filled hollow-core
fibers constitute perhaps the most viable solution towards ultrafast, compact,
and tunable lasers in the UV spectral region. Noise and spectral stability of
such broadband sources are key parameters that define their true potential and
suitability towards real-world applications. In order to investigate the
spectral stability and noise levels in these fiber-based DUV sources, we
generate an SC spectrum that extends from 180 nm (through phase-matched
dispersive waves - DWs) to 4 {\mu}m by pumping an argon-filled hollow-core
anti-resonant fiber at a wavelength of 2.45 {\mu}m. We characterize the
long-term stability of the source over several days and the pulse-to-pulse
relative intensity (RIN) noise of the strongest DW at 275 nm. The results
indicate no sign of spectral degradation over 110 hours, but the RIN of the DW
pulses at 275 nm is found to be as high as 33.3%. Numerical simulations were
carried out to investigate the spectral distribution of the RIN and the results
confirm the experimental measurements and that the poor noise performance is
due to the RIN of the pump laser, which was hitherto not considered in
numerical modelling of these sources. The results presented herein provide an
important step towards an understanding of the noise mechanism underlying such
complex light-gas nonlinear interactions and demonstrate the need for pump
laser stabilization
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