Spectrum Parameters Research Articles

Effect of metabolic therapy on the state of the vascular bed in premenopausal dyslipidemia

When scanning the common carotid arteries (CCA), it was found that patients with premenopausal arterial hypertension (AH) with dyslipidemia with reduced estradiol levels had an expansion of the CCA lumen, a decrease in the blood flow rate in the carotid arteries without hemodynamically significant stenoses, which may indicate the development of vascular maladaptation due to a violation of the autoregulation mechanism, due to remodeling of the vascular wall caused by hypoestrogenemia, and indicate more pronounced structural and functional changes in the vessel in the form of arteriosclerosis, increased stiffness of the vascular wall and the development of endothelial dysfunction. Combined therapy with an angiotensin-converting enzyme (ACE) inhibitor and BioDihydroquercetin has a positive effect on structural and functional changes in the vascular wall of the CCA, endothelial dysfunction improves lipid spectrum parameters, reduces the stiffness of the vascular wall of the arteries. The drug BioDihydroquercetin, produced with trade mark “Baikal Legend”, is a natural immunomodulator, antioxidant, capillaroprotector, strengthens blood vessels, improves blood microcirculation, it is recommended to slow down the aging process of the body

CT perfusion combined with energy spectrum imaging to evaluate the short-term efficacy of bronchial arterial chemoembolization for lung cancer

Objective: To evaluate the clinical value of dynamic volumetric CT perfusion combined with energy spectrum imaging in bronchial arterial chemoembolization (BACE) in patients with lung cancer. Methods: The data of 31 patients with lung cancer confirmed by pathology and treated with BACE in Lishui Central Hospital from January 2018 to February 2022 were retrospectively collected, including 23 men and 8 women, aged 31-84 (67) years. All patients received perfusion scans of lesion sites within 1 week before surgery and 1 month after surgery. We collected and compared the changes in preoperative and postoperative perfusion parameters such as blood flow (BF), blood volume (BV), mean through time (MTT), permeability surface (PS) and energy spectrum parameters including arterial phase CT value (CTA), venous phase CT value (CTV), arterial phase iodine concentration (ICA), venous phase of iodine concentration (ICV), arterial standardization iodine concentration (NICA), and intravenous standardized iodine concentration (NICV) to confirm the significance of these parameters in evaluating the short-term efficacy of BACE in the treatment of advanced lung cancer. Data normality was tested using the Kolmogorov-Smirnov test and normally distributed measurement data are expressed here as mean ± standard deviation; the independent-samples t-test was used for comparisons between two groups. The measurement data that were not normally distributed are expressed as median (interquartile interval) [M (Q1, Q3)], and the comparison between the two groups used the Kruskal-Wallis test. Count data are expressed as cases (%), and comparisons between groups used the χ2 test. Results: The objective response rate (ORR) and disease control rate (DCR) at 1 month after BACE were 54.8% (17/31) and 96.8% (30/31), respectively. CT perfusion parameters and energy spectrum parameters of patients before and after BACE treatment were compared. The results showed that BF, BV, MTT, ICA, ICV and NICV were significantly decreased after BACE treatment compared with before treatment, and the differences were statistically significant[58.06 (40.47,87.22) vs.23.57(10.92, 36.24) ml·min-1·100g-1,3.33(2.86,6.09) vs.2.12(1.96,3.61)ml/100g,2.70(2.19,3.88) vs.1.53 (1.12,2.25)s, 3.51 (3.11,4.14)vs.1.74 (1.26,2.50)mg/ml,2.00 (1.30,2.45) vs.1.32(0.92,1.76)mg/ml,0.51(0.42,0.57) vs.0.33(0.23,0.39)](all P<0.05). At the same time, compared with the non-remission group, the study results showed that the difference of parameters in remission group before and after BACE was more obvious, including ΔBF, ΔBV, ΔMTT, ΔPS, ΔCTA, ΔCTV, ΔICA, ΔICV, ΔNICA, ΔNICV were significantly increased, and the difference was statistically significant [36.82(32.38, 45.34) vs.9.50(-1.43, 12.34) ml·min-1·100g-1,4.46(2.52, 5.79) vs.0.22(-0.76, 4.09) ml/100g,4.22(2.25, 6.77) vs.0.43(-2.53, 1.88) s,10.07 (2.89, 13.13) vs.-2.01(-6.77, 4.28) ml·min-1·100g-1,14.22(11.88, 20.57) vs.4.18(-5.25, 6.37) HU, 34.6(14.88, 43.15) vs.11.60(0.26, 25.05) HU,0.95(0.54, 1.47) vs.0.11(0.20, 0.59) mg/ml,1.57(1.10, 2.38) vs. 0.26(-0.21, 0.63) mg/ml,0.05(0.03, 0.08) vs.-0.02(-0.04, 0.01),0.18(0.13, 0.21)vs. 0.11(-0.06, 0.16)](all P<0.05). Conclusions: CT perfusion combined with spectral imaging could effectively evaluate the changes in tumor vascular perfusion in patients with advanced lung cancer before and after BACE treatment, which has important value in judging the short-term efficacy after treatment.

Magnetic-field-controlled spin valve and spin memory based on single-molecule magnets

A single-molecule magnet is a long-sought-after nanoscale component because it can enable us to miniaturize nonvolatile memory storage devices. The signature of a single-molecule magnet is switching between two bistable magnetic ground states under an external magnetic field. Based on this feature, we theoretically investigate a magnetic-field-controlled reversible resistance change active at low temperatures in a molecular magnetic tunnel junction, which consists of a single-molecule magnet sandwiched between a ferromagnetic electrode and a normal metal electrode. Our numerical results demonstrate that the molecular magnetism orientation can be manipulated by magnetic fields to be parallel/antiparallel to the ferromagnetic electrode magnetization. Moreover, different magnetic configurations can be “read out” based on different resistance states or different spin polarization parameters in the current spectrum, even in the absence of a magnetic field. Such an external magnetic field-controlled resistance state switching effect is similar to that in traditional spin valve devices. The difference between the two systems is that one of the ferromagnetic layers in the original device has been replaced by a magnetic molecule. This proposed scheme provides the possibility of better control of the spin freedom of electrons in molecular electrical devices, with potential applications in future high-density nonvolatile memory devices.

Study on the Vertical Structure and the Evolution of Precipitation Particle Spectrum Parameters of Stratocumulus Clouds over North China Based on Aircraft Observation

The understanding of the macro- and micro-structure, particle spectrum parameters, and their evolutions in different parts of stratocumulus clouds based on aircraft observation data, is important basic data for the development of cloud microphysical parameterization schemes and the quantitative retrieval of cloud-precipitation by radar and satellite detections. In this study, a total of ten vertical measurements during three aircraft observations were selected to analyze the vertical distribution of cloud microphysical properties in different parts of stratocumulus clouds in Hebei, North China. It was found that the downdraft in the cumulus cloud area was stronger than that in the stratiform cloud area, with the temperature at the same height higher than that in the stratiform cloud area, and the height of the 0 °C layers was correspondingly higher. In terms of particle spectrum parameters, the intercept and slope parameters of particle spectrum below melting levels in the cumulus part were higher than those in stratiform clouds area in the same weather process. In different vertical detection, it was found that the ice particles have begun to melt in the negative temperature layer near 0 °C level, and there might be sublimation, fragmentation, and aggregation in the melting process of ice phase particles. In addition, the melting process changed the spectral parameters greatly and also changed the correlation between the intercept and slope of the particle spectrum. The slope below the 0 °C level increased with the increase of intercept, which was greater than that above the 0 °C level. The relationship obtained between the intercept parameter of the particle’s spectrum and temperature, and the correlation between the maximum diameter and slope parameter of the particle spectrum, have certain reference significance for cloud physical parameterization and the quantitative retrieval of cloud precipitation by radar and satellite in North China and similar climate background areas.

Multifractal analysis of flow instability of centrifugal compressor with dynamic pressure

In order to identify the surge, multifractal spectrums are investigated in the analysis of dynamic pressure at the outlet of centrifugal compressor with 800 kW. At first, the time series of dynamic pressure, including stable and unstable states, are obtained. Then, the relationships between characteristics of multifractal spectrums and dynamic pressure series are studied and explained in detail. The results show that the multifractal spectrum parameter Δf(α) is narrow as the centrifugal compressor is working in stable state. However, Δf(α) becomes wide, as it is working in unstable states. Finally, probability analysis of multifractal variation tendency is used to describe the predictability of the variation. The studies indicated that the associated probability between the data of adjacent periods is highest and the predictability is the strongest in transition period. Thus, the method can be used to predict and avoid surge for centrifugal compressor in early time.

Application of CT functional imaging in the assessment of chemotherapy efficacy in lung cancer

ABSTRACT In this research, we aim to investigate the feasibility of a one-stop CT energy spectrum perfusion imaging technique for chemotherapy efficacy assessment of lung cancer patients by obtaining both functional imaging parameters of energy spectrum and perfusion in one scan. From November 2018 to February 2020, a group of 23 patients with pathologically confirmed lung cancer were chosen to undergo CT energy spectrum scans both before and after treatment. The post-treatment CT perfusion data was acquired one week after the second conventional chemotherapy session. Out of the 23 patients, 15 were in the chemotherapy effective group and the remaining 8 were in the ineffective group. The reason for this group was according to recist criteria. Arterial phase iodine concentration (icap) and intravenous phase iodine concentration (icpp) of the lesions were measured, and standardized iodine base values (nic) were calculated. The maximum diameter of the tumor before and after treatment was compared to the perfusion parameters and energy spectrum parameters before and after chemotherapy in the effective group and the invalid group was compared by two tests that p<0.05. The differences between the maximum diameter of the tumor before and after chemotherapy. 2 of the 15 patients in the effective group had liquefied necrotic areas in their lesions. One-stop ct energy-spectrum perfusion imaging can show the disease progression from a functional perspective and assess the efficacy early according to the changes in perfusion parameters and energy-spectrum parameters after lung cancer treatment.

Particle production during inflation: constraints expected from redshifted 21 cm observations from the epoch of reionization

We examine a type of feature in the primordial scalar power spectrum, namely, the bump-like feature(s) that arise as a result of burst(s) of particle production during inflation. The latest CMB observations by Planck 2018 can accommodate the imprints of such primordial features. In the near future, observations of redshifted 21 cm signal from the Epoch of Reionization (EoR) can put additional constraints on inflation models by exploiting the expected tomographic information across a wide range of co-moving wave-numbers. In this work, we study the potential of upcoming observational data from SKA-Low to constrain the parameters of the primordial power spectrum with bump-like features. We use simulated mock data expected from SKA-Low, with uncertainties estimated from different foreground removal models, and constrain the parameters of primordial features within a Bayesian framework. We study two scenarios: in the first scenario, where the astrophysical parameters relevant to the EoR are known, we find that 21 cm power spectra do have the potential to probe the primordial bump-like features. As the input amplitude of the bump is decreased below roughly 10% of the amplitude of the primordial power spectrum without the bump, the uncertainties in the recovered values for both amplitude and location of the bump are found to increase, and the recovered values of the location of the bump also get increasingly more biased towards higher values. Hence, it becomes harder to constrain these parameters. In the second scenario, we analyze the achievable constraints on primordial features when two of the EoR parameters, namely, minimum halo mass and ionizing efficiency, are uncertain. We find that the effect of the bump on the profile and the amplitude of the 21 cm power spectrum is distinct from the impact of changing the astrophysical parameters, and hence they may potentially be distinguished.

All Spectral Type LAMOST Spectra Library (ATLAS)

We present an empirical stellar spectra library, ATLAS, with resolution R ∼ 1800 and wavelength coverage from 3800–8700 Å. These spectra are homogeneously observed by the Large Sky Area Multi-Object Fiber Spectroscopic Telescope and have been released in its DR5. ATLAS is separated into two groups, ATLAS-A and -T. The former contains 5584 spectra covering spectral types from O- to M-type and some special types such as A supergiant, blue horizontal-branch, and carbon stars. All of the spectra have absolutely calibrated fluxes at certain characteristic wavelengths corresponding to the optical passbands with accuracy better than 2.9% by comparing with PanSTARRS1 g-, r-, and i-band photometry. In addition, greater than 1% systematic uncertainty from the fundamental calibration should be considered separately. ATLAS-A contains 5342 spectra with spectral energy distribution effective temperature, surface gravity, and metallicity and 242 spectra with only the effective temperature and surface gravity. These parameters are consistent with the spectroscopic derived parameters of the same stars. Compared to current empirical libraries, ATLAS-A contains more cool giant stars, which may play a critical role in understanding the evolution of galaxies. ATLAS-T, on the other hand, contains 1118 spectral templates averaging over spectra with similar stellar parameters from ATLAS-A. It smooths out some special features in the individual spectra and can be used as a “standard” atlas of stellar spectra. Containing stellar spectra with almost all normal types, ATLAS may not only be a complete training data set for stellar spectra parameter determination but also an ideal legacy for stellar population synthesis.

Thermal effects of the excitation laser power on carbonaceous meteorite Northwest Africa 6603 by Raman spectroscopy: an undergraduate research project

Raman spectroscopy has been used extensively on meteoritic samples since it is a nondestructive tool that provides information about their structure and mineralogical composition, which can give important clues about planet formation. However, the power of the excitation laser used in this technique can alter the properties of the samples due to thermal effects. In this undergraduate research work, the laser-induced thermal effects produced on the carbonaceous chondritic meteorite Northwest Africa 6603 were studied in detail by analyzing the low- and high-resolution Raman spectra parameters of the minerals found in the inclusions and matrix of this sample as a function of the excitation power. Olivine (forsterite), graphitic carbon, pyroxene (enstatite), hematite and gehlenite were the minerals identified in the studied regions. The Raman parameters of these minerals were affected by the laser power to a greater or lesser extent, indicating an increase in structural disorder. In general, the alterations observed were permanent (reverse changes were not observed). These thermal effects were correlated with the topography of the irradiated regions by analyzing their changes using optical microscopy. The micrographs of a few regions showed changes on their topography after irradiating the regions with the maximum applied power (e.g., more depressed areas). These findings exhibited strong evidence of the thermal effects induced by the laser power on the materials found in this fragment, which must be considered to avoid alterations of the physical and chemical properties of the meteoritic samples. In addition, this work presents the first study done on the mineralogical composition of Northwest Africa 6603 using Raman spectroscopy. Furthermore, from an educational standpoint, this project exposed the involved undergraduate physics students to numerous research steps (e.g., experiment preparation, data acquisition/analysis, and manuscript preparation) which provided them with a broad spectrum of valuable scientific and technical tools for their future careers.

A cotton leaf nitrogen monitoring model based on spectral-fluorescence data fusion

In the present study, hyperspectral imaging and remote sensing of fluorescence were integrated to monitor the nitrogen content in leaves of drip-irrigated cotton at different growth periods in northern Xinjiang, China. Based on the spectrum and chlorophyll fluorescence parameters of nitrogen content in cotton leaves of different growth periods obtained through the shuffled frog-leaping algorithm (SFLA), the successive projection algorithm (SPA), grey relational analysis (GRA), and competitive adaptive reweighted sampling (CARS), a monitoring model of nitrogen content in cotton leaves was established via on hyperspectral imaging, chlorophyll fluorescence parameters, and spectral-fluorescence data fusion. The results showed that: (1) there were significant positive correlations between the chlorophyll fluorescence parameters Fv'/Fm', Fv/Fm, Yield, Fm, NPQ, and the nitrogen content at each growth period. (2) The effectiveness of chlorophyll fluorescence parameters in inversion of nitrogen content was the highest at the budding period and the blooming period, and the coefficients of determination (R2) of the validation sets were 0.745 and 0.709, respectively. (3) In the monitoring model for cotton leaf nitrogen in the blooming period that was established based on the decision-level algorithm and spectral-fluorescence data fusion, the R2 value of the training set reached 0.961, and that of the validation set was 0.828. In conclusion, the findings of this study suggest that the feature-level fusion and decision-level fusion algorithms of spectral-fluorescence data can effectively improve the accuracy and reliability of cotton leaf nitrogen monitoring.

Effect of the Gaussian distribution parameters of the electron beam generated at the target on the simulated x-ray dose

The purpose of this work was to investigate by Monte Carlo method the adjustment of photon beams delivered by the medical LINear ACcelerator (LINAC) Elekta Synergy MLCi2. This study presents an optimization of the Gaussian distribution parameters of the accelerated electrons before the target simulated by two Monte Carlo codes and for three beams. The photon (x-ray) beam is produced by the interaction of accelerated electrons with the LINAC target. The electrons are accelerated by a potential difference created between the anode and the cathode of the gun and directed towards the target. In the Monte Carlo simulation, it is necessary to setup the spectrum parameters of the generated electrons to simulate the x-ray dose distribution. In this study, we modeled the LINAC geometry for photon beams 18MV and 6MV in cases Flattened (FF) and Flattening-Filter-Free (FFF). The Monte Carlo simulations are based on G4Linac_MT and GATE codes. The results of the optimized configurations determined after more than 20 tests for each beam energy show a very good agreement with the experimental measurements for different irradiation fields for the depth (PDD) and lateral (Profile) dose distribution. In all Monte Carlo calculations performed in this study, the statistical uncertainty is less than 2%. The results were also in very good agreement in terms of γ-index analysis, for the 3%/3 mm and 2%/2 mm criteria.

Preparation and quantitative analysis of multicenter luminescence materials for sensing function.

Luminescent sensing materials are attractive for environmental analysis due to their potential for high selectivity, excellent sensitivity and rapid (even instantaneous) response towards targeted analytes in diverse sample matrices. Many types of analytes have been detected in samples of wastewater for environmental protection, reagents and products in industrial production of drugs and pesticides, and biological markers in blood and urine for early diagnosis. It is still challenging, however, to develop appropriate materials with optimal sensing function for a targeted analyte. Here we synthesize metal-organic frameworks (MOFs) bearing multiple luminescent centers, such as metal cations (for example, Eu3+ and Tb3+), organic ligands and guests, which are chosen for optimal selectivity for the analytes of interest, including industrial synthetic intermediates and chiral drugs. Interaction between the metal node, ligand, guest and analyte results in a complex system with different luminescence properties compared with the porous MOF on its own. The operation time for the synthesis is usually less than 4 h; the quick screening for sensitivity and selectivity takes ~0.5 h and includes steps to optimize the energy levels and spectrum parameters. It can be used to accelerate the discovery of advanced sensing materials for practical applications.

Exploratory Study on the Associations between Lifetime Post-Traumatic Stress Spectrum, Sleep, and Circadian Rhythm Parameters in Patients with Bipolar Disorder.

The present study aimed at exploring whether lifetime post-traumatic stress spectrum symptoms are associated with chronotype in patients with bipolar disorder (BD). Moreover, we explored whether the chronotype can moderate the potential associations between lifetime post-traumatic stress spectrum symptoms and rest-activity circadian and sleep-related parameters. A total of 74 BD patients were administered the Trauma and Loss Spectrum Self-Report (TALS-SR) lifetime version for lifetime post-traumatic stress spectrum symptoms, the Pittsburgh Sleep Quality Index (PSQI) for self-reported sleep quality, and the Reduced Morningness-Eveningness Questionnaire (rMEQ) to discriminate evening chronotypes (ETs), neither chronotype (NT), and morning chronotype (MT). Actigraphic monitoring was used to objectively evaluate sleep and circadian parameters. Patients classified as ET reported significantly higher scores in the re-experiencing domain, as well as poorer sleep quality, lower sleep efficiency, increased wake after sleep onset, and delayed mid-sleep point compared with both NT and MT (p-value ≤ 0.05). Moreover, ET presented significantly higher scores in the TALS-SR maladaptive coping domain than NT and lower relative amplitude than MT (p-value ≤ 0.05). Moreover, higher TALS-SR total symptomatic domains scores were significantly correlated with poor self-reported sleep quality. Regression analyses showed that the PSQI score maintained the association with the TALS total symptomatic domains scores after adjusting for potentially confounding factors (age and sex) and that no interaction effect was observed between the chronotype and the PSQI. Conclusions: This exploratory study suggests that patients with BD classified as ET showed significantly higher lifetime post-traumatic stress spectrum symptoms and more disrupted sleep and circadian rhythmicity with respect to other chronotypes. Moreover, poorer self-reported sleep quality was significantly associated with lifetime post-traumatic stress spectrum symptoms. Further studies are required to confirm our results and to evaluate whether targeting sleep disturbances and eveningness can mitigate post-traumatic stress symptoms in BD.

Regulation of external electric field on sensitivity of ICM energetic materials.

[2,2'-Bi(1,3,4-oxadiazole)]-5,5'-dinitramide (ICM-101), 2,4,6-triamino-5-nitropyrimidine-1,3-dioxide (ICM-102), and 6-nitro-7-azido-pyrazol[3,4-d][1,2,3]triazine-2-oxide (ICM-103) are excellent China-made explosives, but their performance under external electric fields (EEF) has never been explored, especially sensitivity. To study the induction effect of EEF on it, the chemical reactivity, electron localization function (ELF), spectrum, and other parameters were calculated by density functional theory. The results show that the increasing EEF can weaken the △EHOMO-LUMO (△EHOMO-LUMO = EHOMO-ELUMO) materials, making the stability worse and the sensitivity higher. The proportion of the positive electrostatic surface potential area is also smaller under the increasing EEF, indicating that ICM molecules are becoming more and more unstable. The ELF and localized orbital locator (LOL) decrease with the increase of EEF strength, which suggests that the trigger bond length increases, the EBDE decreases, and the molecular sensitivity increases. When the intensity of EEF increases, the absorption peak of the molecular spectrum gradually redshifts, and even a weak new absorption peak appears, indicating that the color of the material may change. Finally, EEF strength affects electron density, nitro charge, and chemical reactivity parameters. Gaussian 16 software was used for calculation. The calculation levels are B3LYP/6-311G+ (d, p) and B3LYP/Def2-TZVPP. The optimized structure has a local true minimum energy on the potential energy surface and no imaginary frequency. Multiwfn 3.8 and VMD 1.9.3 were used in this work to analyze the ICM series of energetic material wave functions. The strength range of EEF is 0.000-0.016 a.u., and the increasing gradient is 0.002 a.u.

Prospects for LISA to detect a gravitational-wave background from first order phase transitions

First order phase transitions in the early universe could produce a gravitational-wave background that might be detectable by the Laser Interferometer Space Antenna (LISA). Such an observation would provide evidence for physics beyond the Standard Model. We study the ability of LISA to observe a gravitational-wave background from phase transitions in the presence of an extragalactic foreground from binary black hole mergers throughout the universe, a galactic foreground from white dwarf binaries, and LISA noise. Modelling the phase transition gravitational wave background as a double broken power law, we use the deviance information criterion as a detection statistic, and Fisher matrix and Markov Chain Monte Carlo methods to assess the measurement accuracy of the parameters of the power spectrum. While estimating all the parameters associated with the gravitational-wave backgrounds, foregrounds, and LISA noise, we find that LISA could detect a gravitational-wave background from phase transitions with a peak frequency of 1 mHz and normalized energy density amplitude of Ωp ≃ 3 × 10-11. With Ωp ≃ 10-10, the signal is detectable if the peak frequency is in the range 4 × 10-4 to 9 × 10-3 Hz, and the peak amplitude and frequency can be estimated to an accuracy of 10% to 1%.

Investigating Dynamical Complexity and Fractal Characteristics of Bitcoin/US Dollar and Euro/US Dollar Exchange Rates around the COVID-19 Outbreak.

This article investigates the dynamical complexity and fractal characteristics changes of the Bitcoin/US dollar (BTC/USD) and Euro/US dollar (EUR/USD) returns in the period before and after the outbreak of the COVID-19 pandemic. More specifically, we applied the asymmetric multifractal detrended fluctuation analysis (A-MF-DFA) method to investigate the temporal evolution of the asymmetric multifractal spectrum parameters. In addition, we examined the temporal evolution of Fuzzy entropy, non-extensive Tsallis entropy, Shannon entropy, and Fisher information. Our research was motivated to contribute to the comprehension of the pandemic's impact and the possible changes it caused in two currencies that play a key role in the modern financial system. Our results revealed that for the overall trend both before and after the outbreak of the pandemic, the BTC/USD returns exhibited persistent behavior while the EUR/USD returns exhibited anti-persistent behavior. Additionally, after the outbreak of COVID-19, there was an increase in the degree of multifractality, a dominance of large fluctuations, as well as a sharp decrease of the complexity (i.e., increase of the order and information content and decrease of randomness) of both BTC/USD and EUR/USD returns. The World Health Organization (WHO) announcement, in which COVID-19 was declared a global pandemic, appears to have had a significant impact on the sudden change in complexity. Our findings can help both investors and risk managers, as well as policymakers, to formulate a comprehensive response to the occurrence of such external events.

Discovery of solid bitumen in the Cambrian reservoirs and its geological implications in the Ordos Basin, China

This study reports a comprehensive geochemical analysis of several samples of the solid bitumen recently discovered in the Cambrian reservoirs in drillings and outcrops in the Ordos Basin. The results show that the solid bitumen in the reservoir features intergranular pores and micro-fractures, with mineral particle surfaces of dolomite and limestone, and relatively clear and flat boundaries. The D and G peaks in the laser Raman spectrum were prominent. According to distributions of shapes of the D and G peaks and the relevant parameters of the laser Raman spectrum, the vitrinite equivalent reflectance (Roeq) values were from 2.12% to 3.46% in the solid bitumen. This indicates that the solid bitumen in the reservoirs had undergone significant thermal evolution and was mainly composed of pyrobitumen. Moreover, it mainly consisted of four types of atoms, C, O, Ca, and Mg, which confirms the hypothesis of the significant thermal evolution of the samples. In addition, the analysis of the origin of the Cambrian natural gas and the correlation between the solid bitumen and the potential source rocks show that the solid bitumen in the Cambrian reservoirs of the Southern Basin had features similar to those of the Lower Cambrian source rocks, except for the samples from well T59. All evidence suggests that the high-abundance source rocks of the Lower Cambrian have made considerable contributions to the Cambrian natural gas and the solid bitumen in the Cambrian reservoirs of the Southern Basin. The work here provides a new scientific basis for exploring natural gas in the Cambrian reservoirs and deep strata of the Ordos Basin.

Fish size spectrum as a complementary biomonitoring approach of freshwater ecosystems

Freshwater bioindicators have been developed to assess ecosystem health and responses to human-induced stressors. To date, most bioindicators primarily rely on the species identity of plant and animal communities and do not account for interactions among organisms and fluxes of energy between trophic levels. Body size is one of the most important ecological traits in aquatic ecosystems because it governs interactions among organisms and is affected by environmental conditions but, surprisingly, many of assessment approaches do not use individual body size. The community size spectrum is defined as the linear relationship between the abundance and the body size of organisms and reflects several important ecological features including ecosystem carrying capacity, predation-prey interactions, and trophic energy fluxes. In this study, we explored the potential of using the size spectrum parameters (slope, elevation and linearity) of fish community as a complementary bioindicator in 51 natural lakes and 102 reservoirs distributed across France. We determined how the fish size spectrum and other common bioindicators based on fish, macrophyte and phytoplankton communities responded to the water quality degradation, littoral habitat alterations and fish invasions. Results demonstrated that: (i) the size spectrum was driven by water quality degradation both in lakes and reservoirs, while size spectrum was affected by habitat loss in natural lakes and by fish invasion in reservoirs and (ii) the size spectrum was more sensitive to habitat loss than common bioindicators in natural lakes. This study highlights that the use of fish community size spectrum could provide additional insights into our understanding of the responses of freshwater ecosystems to global changes and could serve to improve the efficiency of management programs. This can be done at very limited additional cost because fish body size is commonly measured in biomonitoring protocols.

The effect of serum lipids and spermoplasm on the stallion sperm quality

The quality and cryoresistance of stallion sperm depend on many endogenous and exogenous factors. One of the factors affecting the sperm quality are the parameters of the lipid spectrum of spermoplasm and blood serum. Lipase activity, cholesterol and triglyceride content in blood serum and spermoplasm were studied in 19 stallions of the Arabian breed aged from 5 years to 15 years (on average 10.1±0.3 years). It was found that lipase activity in the spermoplasm (217.0 U/l) is on average 11.4 times higher than in the blood serum (19.1 U/l). The concentration of spermoplasm triglycerides (1.3 mmol/l) is on average 4.3 times higher than in blood serum (0.3 mmol/l). The concentration of cholesterol in the blood serum (2.4 mmol/ l) is on average 12 times higher than the same indicator in the stallion spermoplasm (0.2 mmol/l). The relationship between the parameters of the lipid spectrum of blood serum and spermoplasm with the characteristics of stallion sperm was studied. A significant relationship was found between the activity of lipase in blood serum with progressive mobility (r=0.66; p=0.006) and survival (r=0.67; p=0.005) of spermatozoa in cryopreserved sperm.

Smoothing of the Time-Resolved Spectral Matrix Obtained by a Streak Camera: Estimation of the Fluorescence Band Parameters

A new method based on singular value decomposition (SVD) was applied to the denoising of the time-resolved spectral matrix (TRSM), which was obtained by a streak camera. The least informative principal components (PCs) were filtered out using the Tikhonov regularization principle. A method for determining the quasi-optimal regularization parameter was suggested. The SVD method was compared with the moving average time direction (MATD) smoothing of the TRSM. Numerical simulations and experimental study of the 3-aminophthalimide (3AP) solution in acetonitrile showed that the SVD smoothing allowed for accurate measurement of signals in peak maximum. Fitting the polynomial modified Gaussian to the smoothed fluorescent bands decreased the measurement errors of the maximum peak position and its width. This method allowed us to obtain kinetics data of the fluorescence band parameters of the 3AP spectrum in an acetonitrile solution. Flexible selection of the quasi-optimal processing parameters and a better time resolution are the main advantages of the SVD method over MATD.