Subspace Distribution Clustering HMM for Chinese Digit Speech Recognition

As a kind of statistical method, the technique of Hidden Markov Model （HMM） is widely used for speech recognition. In order to train the HMM to be more effective with much less amount of data, the Subspace Distribution Clustering Hidden Markov Model （SDCHMM）, derived from the Continuous Density Hidden Markov Model （CDHMM）, is introduced. With parameter tying, a new method to train SDCHMMs is described. Compared with the conventional training method, an SDCHMM recognizer trained by means of the new method achieves higher accuracy and speed. Experiment results show that the SDCHMM recognizer outperforms the CDHMM recognizer on speech recognition of Chinese digits.

Effects of Seasonal Variations in Physical Parameters on Quality of Gravity Flow Water in Kyanamira Sub-County, Kabale District, Uganda

The effect of seasonal variations in physical parameters on quality of gravity flow water was investigated in Kyanamira Sub-County, Kabale District, Uganda. The seasonal variations in the physical parameters (pH, temperature, electrical conductivity (EC), turbidity, colour, total dissolved solids (TDS), and total suspended solids (TSS)) were determined during wet and dry seasons. Composite samples from gravity flow water sources were collected monthly from March to August, 2014 and then analyzed. Temperature was measured using thermometer;pH, EC and TDS were determined using a multimeter, turbidity, colour and total suspended solids were determined by spectrophotometric method. TDS, pH and temperature were the most contributing parameters to water quality variations in both seasons. The mean pH values varied between 3.78 - 4.84 from March to August, 2014 at all study sites. These pH values were consistently below the WHO permissible range of 6.5 - 8.5. Similarly, total suspended solids varied between 0.66 - 2.17 mg·L-1 and were well above the recommended WHO limit of zero mg·L-1 at all study sites. Turbidity mean values varied between 0.83 - 3.7 NTU and were outside the recommended limits of 3 NTU at Kigata (3.7 NTU) only. Temperatures (20.3°C - 21.15°C) for all the study sites were within the recommended limit of 20°C - 30°C in water for domestic purposes. The mean values of physical parameters for the wet season were: temperature (21.12°C), colour (12.5 PtCoU), turbidity (3.4 NTU), TDS (76.76 mg·L-1), TSS (2.13 mg·L-1), pH (4.19) and EC (152.7 μS·cm-1) were different from those of the dry season (temperature (20.99°C), colour (0.93 PtCoU), turbidity (0.53 NTU), TDS (77.33 mg·L-1), TSS (0.67 mg·L-1), pH (4.86) and EC (158.65 μS·cm-1). Basing on these findings above, it was evident to justify discouraging the use of gravity flow water at these study sites for domestic purposes without proper treatment.

Soil CO2 Efflux Dynamics and Its Relationship with the Environmental Variables in a Sub-Tropical Mixed Forest

Soil CO2 efflux is an ongoing process of respiration from soil;plant parts/ microbes below the ground to the atmosphere which is known for faster cycling of carbon sources. A large portion of carbon sequestered and fixed by forests is returned to the atmosphere through soil CO2 efflux and multiple controlling parameters mainly temperature, precipitation, and growth factors interact with the soil CO2 efflux variation. This study assessed the soil CO2 efflux every month for consecutive 2-years (August 2015 to July 2017) by using the closed chamber method to determine the role of ecological parameters that govern the soil CO2 efflux and its temporal modification in a sub-tropical mixed forest of central region in Nepal. The results of this study manifested that soil CO2 efflux accounted 63.2% (y = 31.96e0.128x), 71.3% (y = 44.77e0.123x) and 64.5% (y = 44.11e0.117x) variations in soil temperature with significantly (p < 0.05) exponential positive relation in the year 2015/2016, 2016/2017 and the two years when merged. And the temperature sensitivity value (Q10) of the soil CO2 efflux was 3.6, 3.4, and 3.2, respectively. Soil water content also expressed significantly (p < 0.05) positive exponential effect on soil CO2 efflux and accounted 62.0% (y = 138.3e0.057x), 46.1% (y = 88.42e0.052x) and 40.5% (y = 133.1e0.0447x) in its variability in different years and the merged years. Evident variations of soil CO2 efflux, soil temperature, soil water content, and litter were observed in the forest seasonally and inter-annually. Two years mean total annual soil CO2 efflux of the forest was estimated at 904.76 g C·m-2·y-1. The study revealed that sub-tropical forests could be more influenced by precipitation regimes in progressing warm climates i.e. vulnerable to climate change, illustrating the comprehensive dynamics of the representative forest carbon cycle in the tropical region.

EPR Study of a New Crystal of the Binuclear Copper（Ⅱ） Cluster Compound－〔Cu2(α－C10H7CH2CO2)4－（DMF）2〕·（DMF）2·H2O

In this paper, single crystal EPR study of a new binuclear copper (Ⅱ) cluster compound-[Cu2(α-C(10) H7CH2CO2)4 (DMF)2]·[DMF]2·H2O](DMF= (CH3)2NCOH) at room temperature is reported. The lines of △Ms=±1 allowing transition and △M=2 forbiding transition are shown in EPR spectra. The experimental data are consistent with the calculated results by the leastsquares fitting prograrn in three principal planes of g and D tensors. The spin Hamiltonian parameters are as follows: gx=2. 1482, gy=2. 0529 ,gz=2. 3905, D= 0. 348 cm￣(-1) and E =0. 01 cm-1. The diagrams of the energy levels have been obtained when the magnetic field is oriented to three principal axes. The polycrystal EPR spectra have been measured at room temperature and 77K, respectively.and the parameters of these spectra are given (g∥= 2. 094, g⊥= 2. 425, D= 0. 37 cm-1,E=0). The parameter of the isotropic magnetic exchange interaction J=-254cm-1 is determined, and that of the anisotropic magnetic exchange J1=-153 cm-1 is calculated. The average magnetic susceptibility of the polycrystal sample χ= 1. 39 ×10-6 (c. g. s) has been measured by Faraday powder method. Thus the average magnetic mornent μ=1. 43 B. M. can be calculated. It is shown that the exchange interactions between the metal ions of the binuclear copper(Ⅱ) cluster compound are confirmed antiferromagnetic In nature.

Method of moving target detection based on sub-image cancellation for single-antenna airborne synthetic aperture radar

The method of moving target detection based on subimage cancellation for single-antenna airborne SAR is presented. First the subimage is obtained through frequency processing is pointed out. The imaging difference of a stationary objects and moving object in the subimage based on the frequency division is analyzed from the fundamental principle. Then the developed method combines the shear averaging algorithm to focus on the moving target in the subimage, after the clutter suppression and the focusing position in each subimage is obtained. Next the observation model and the relative movement of the moving targets between the subimages estimate the moving targets. The theoretical analysis and simulation results demonstrate that the method is effective and can not only detect the moving targets, but also estimate their motion parameters precisely.

Recovery of oil and free fatty acids from spent bleaching earth using sub-critical water technology supported with kinetic and thermodynamic study

This work represents the extraction of oil with high free fatty acid content from spent bleaching earth using sub-critical water technology as a greener production pathway. The extraction efficiencies under different conditions were investigated. The studied parameters include temperatures in the range of 180 to 270°C, the feed to solventfeed-to-solvent (in this case water) ratio (1:1, 1:2, 1:3, 1:4 and 1:5) and extraction times in the range of 5-60 minutes. The results showed that the optimum temperature, feed to solventfeed-to-solvent ratio, and extraction time were 270°C, 1:3, and 20 minutes, respectively. In another experiment, the extracted free fatty acids were converted into mono-, di-, and triglycerides through esterification with glycerol to increase the value added of the extracted products. The kinetics of the extraction process was found to be corresponding to an irreversible consecutive unimolecular-type first order reaction, consisting of the extraction step followed by the decomposition reaction step. Both reaction rates of extraction and decomposition were estimated using the reaction rate equations utilizing the nonlinear regression method. The apparent activation energy was calculated to be 46.1 kJ·mol-1. This result indicates a diffusion controlled reaction. For more exploration and deep understanding of the extraction mechanism, other thermodynamic parameters were also calculated and analyzed including,ΔH#, ΔS#, and ΔG# of the extraction step.

Evaluation of Acute and Sub-Acute Oral Toxicities of Momordica foetida Schumach. (Cucurbitaceae) Leaves Methanol Extract in Wistar Rats

Momordica foetida is a plant widely used in tropical Africa to manage gastroenteric diseases. Previous studies demonstrated interesting antibacterial activity against human pathogenic bacteria. However, the security or toxicity of methanol leaf extract has not been determined yet. The aim of this study was to evaluate the acute and sub-acute toxicity of the leaf extract of Momordica foetida. In the acute toxicity study, a single oral dose of 5000 mg/kg body weight was administered to rats which were observed for 14 days in order to identify signs of toxicity or death. In the sub-acute toxicity, the animals were treated with 250, 500 and 1000 mg/kg of the extract for 28 consecutive days. Body weights and behavior were noted throughout the experiment. Upon treatment, blood and urine were collected for hematological and biochemical analysis. Liver, lungs, heart, kidneys, testes and ovaries were analyzed for relative weights and histopathology. The acute toxicity study of M. foetida leaf extract revealed no signs of toxicity related to the treatment, indicating that the median-lethal-dose (LD50) value is greater than 5000 mg/Kg of body weight. In the sub-acute toxicity assay, the extract did not affect the general behavior of animals, meanwhile, it led to a significant increase in the levels of red blood cells, platelets, hemoglobin, granulocytes and Mid-Cells (MIDs). Biochemical parameters showed an increase in total cholesterol, HDL cholesterol, serum urea, serum and urinary glucose and a decrease in urinary proteins, serum creatinine, urinary urea levels, serum activities of AST, ALT and proteins levels, as well as increases in lung, spleen and ovaries relative weight were noticed, all compared to control animals. Histological analysis revealed a normal architecture of kidneys, liver, heart, lung, ovaries and testes. This study provides valuable data on the safety of per os administration of Momordica foetida leaf methanol extract that could be very useful for future assays.

Sub-Harmonic Resonances of Periodic Parameter Excited Oscillators with Discontinuities

It is difficult to obtain analytic approximations of nonlinear problems such as parameter excited system with strong nonlinearity. An analytic approach based on the homotopy analysis method( HAM) is proposed to study the sub-harmonic resonances of highly nonlinear parameter excited oscillating systems with absolute value terms. The non-smoothness of absolute value terms is handled by means of an iteration approach with Fourier expansion. Two typical examples are employed to illustrate the validity and flexibility of this approach. The square residuals of the homotopy-approximations of the two examples decrease to 10-6and 10-5,respectively. Thus,the HAM combining with other methods gives hope to solve complex singular oscillating systems analytically.

Acute and Sub-Chronic Toxicity Evaluation of the Crude Methanolic Bark Extract of Bridelia micrantha (Hochst.) Baill. (Phyllanthaceae) and Its Fraction

Bridelia micrantha, commonly known as coastal golden leaf, is a member of the family Phyllanthaceae. In preliminary studies nine fractions, named F1 - F9, were obtained by fractionating the crude methanol extract of the stem bark of Bridelia micrantha using column chromatographic techniques. The fraction F6 was the most active when tested for antibacterial activity. Thus, toxicity of this fraction was investigated for further use. The present study evaluated the acute and sub-chronic toxicity of the crude methanolic bark extract of Bridelia micrantha and its fraction. The acute toxicity was carried out according to the experimental protocol of Organization for Economic Co-operation and Development (OECD). The plant extract or the fraction F6 was administered orally to female mice at a single dose of 2000 mg/kg and the animals were observed for any behavioral changes or mortality for 14 days. In the sub-chronic toxicity study, the extract and fraction were administered orally at 200, 400 and 800 mg/kg bw/day for 28 days to healthy Wistar rats. The general behavior and body weight of the rats were recorded daily. At the end of the experimental period, hematological and biochemical analyses, changes in vital organ weight (liver, lung, heart, spleen and kidney), and histopathological examination of the liver and kidney were performed. No mortality or adverse effects were noted at the 2000 mg/kg dose during the oral acute toxicity test. In the sub-chronic study, the crude methanolic bark extract of Bridelia micrantha and the fraction F6 induced no mortality or treatment-related adverse effects on body weight, general behavior, relative organ weights, hematological and biochemical parameters. Histopathological examination of the liver and kidney showed normal architecture suggesting no morphological alterations. In conclusion, the oral administration of the crude methanolic bark extract of Bridelia micrantha and the fraction F6 for 28 days at a dosage of up to 800 mg/kg did not induce toxicological damage in rats. From acute toxicity study, the median lethal dose (LD50) of the crude methanolic bark extract of Bridelia micrantha and the fraction F6 was estimated to be more than 2000 mg/kg.

The Influence of Electrode Surface Mercury Film Deformation on the Breakdown Voltage of a Sub-Nanosecond Pulse Discharge Tube

A sub-nanosecond pulse discharge tube is a gas discharge tube which can generate a rapid high-voltage pulse of kilo-volts in amplitude and sub-nanoseconds in width. In this paper, the sub-nanosecond pulse discharge tube and its working principles are described. Because of the phenomenon that the deformation process of the mercury film on the electrode surface lags behind the charging process, the mercury film deformation process affects the dynamic breakdown voltage of the tube directly. The deformation of the mercury film is observed microscopically, and the dynamic breakdown voltage of the tube is messured using an oscillograph. The results show that all the parameters in the charging process, such as charging resistance, charging capacitance and DC power supply, affect the dynamic breakdown voltage of the tube. Based on these studies, the output pulse amplitude can be controlled continuously and individually by adjusting the power supply voltage. When the DC power supply is adjusted from 7 kV to 10 kV, the dynamic breakdown voltage ranges from 6.5 kV to 10 kV. According to our research, a kind of sub-nanosecond pulse generator is made, with a pulse width ranging from 0.5 ns to 2.5 ns, a rise time from 0.32 ns to 0.58 ns, and a pulse amplitude that is adjustable from 1.5 kV to 5 kV.

Temperature-Frequency Characteristics of Dielectric Properties of Compositions LDPE + xvol%Bi2Te3

In the paper, the results of investigations of temperature and frequency dependences of dielectric permeability and dielectric loss of compositions LDPE + xvol%Bi2Te3 are stated. The investigations were carried out at frequency 10 – 105 Hz and temperature 20°C - 150°C intervals, respectively. It was revealed that increase of percentage of the filler Bi2Te3 in the matrix, reduces to increase of dielectric permeability and dielectric loss of composites LDPE + xvol%Bi2Te3 in connection with the change reducing to Maxwell-Wagner’s volume polarization and emergence of comparative strong inner field in semiconductor clusters.

Sub-nm ruthenium cluster catalyst for decomposition as an efficient and robust and synthesis of ammonia： Break the ＂size shackles＂

Downsizing to sub-nm is a general strategy to reduce the cost of catalysts. However, theoretical Wulff-constructed model suggests that sub-nm clusters show little activity for various reactions such as ammonia decomposition and ammonia synthesis because of the lack of active sites. As clusters may deviate from the ideal model construction under reaction conditions, a host-guest strategy to synthesize thermally stable 1.0 run monodispersed Ru dusters by the pyrolysis of MIL-101 hosts is reported here to verify the hypothesis. For ammonia decomposition, the activity of the Ru clusters is 25 times higher than that of commercial Ru/active carbon （AC） at full-conversion temperature, while for ammonia synthesis, the activity of the Ru dusters is 500 times as high as that of promoted Ru NPs counterpart. The catalyst also maintains its activities for 40 h without any increase in the size. This model can be used to develop a host-guest strategy for designing thermally stable sub-nm clusters to atomic-efficiently catalyze reactions.

SUBic:A Scalable Unsupervised Framework for Discovering High Quality Biclusters

A biclustering algorithm extends conventional clustering techniques to extract all of the meaningful subgroups of genes and conditions in the expression matrix of a microarray dataset. However, such algorithms are very sensitive to input parameters and show poor scalability. This paper proposes a scalable unsupervised biclustering framework, SUBic, to find high quality constant-row biclusters in an expression matrix effectively. A one-dimensional clustering algorithm is proposed to partition the attributes, that is, columns of an expression matrix into disjoint groups based on the similarity of expression values. These groups form a set of short transactions and are used to discover a set of frequent itemsets each of which corresponds to a bicluster. However, a bicluster may include any attribute whose expression value is not similar enough to others, so a bicluster refinement is used to enhance the quality of a bicluster by removing those attributes based on its distribution of expression values. The performance of the proposed method is comparatively analyzed through a series of experiments on synthetic and real datasets.

Improved insensitive to input parameters trajectory clustering algorithm

The existing trajectory clustering （TRACLUS） is sensitive to the input parameters c and MinLns. The parameter value is changed a little, but cluster results are entirely different. Aiming at this vulnerability, a shielding parameters sensitivity trajectory cluster （SPSTC） algorithm is proposed which is insensitive to the input parameters. Firstly, some definitions about the core distance and reachable distance of line segment are presented, and then the algorithm generates cluster sorting according to the core dis- tance and reachable distance. Secondly, the reachable plots of line segment sets are constructed according to the cluster sorting and reachable distance. Thirdly, a parameterized sequence is extracted according to the reachable plot, and then the final trajectory cluster based on the parameterized sequence is acquired. The parameterized sequence represents the inner cluster structure of trajectory data. Experiments on real data sets and test data sets show that the SPSTC algorithm effectively reduces the sensitivity to the input parameters, meanwhile it can obtain the better quality of the trajectory cluster.

Combining optical and X-ray observations of galaxy clusters to constrain cosmological parameters

Galaxy clusters present unique advantages for cosmological study.Here we collect a new sample of 10 lensing galaxy clusters with X-ray observations to constrain cosmological parameters.The redshifts of the lensing clusters lie between 0.1 and 0.6,and the redshift range of their arcs is from 0.4 to 4.9.These clusters are selected carefully from strong gravitational lensing systems which have both X-ray satellite observations and optical giant luminous arcs with known redshifts.Giant arcs usually appear in the central region of clusters,where mass can be traced with luminosity quite well.Based on gravitational lensing theory and a cluster mass distribution model,we can derive a ratio using two angular diameter distances.One is the distance between lensing sources and the other is that between the deflector and the source. Since angular diameter distance relies heavily on cosmological geometry,we can use these ratios to constrain cosmological models.Moreover,X-ray gas fractions of galaxy clusters can also be a cosmological probe.Because there are a dozen parameters to be fitted,we introduce a new analytic algorithm,Powell＇s UOBYQA（Unconstrained Optimization By Quadratic Approximation） ,to accelerate our calculation.Our result demonstrates that this algorithm is an effective fitting method for such a continuous multi-parameter constraint.We find an interesting fact that these two approaches are separately sensitive toΩΛandΩM.By combining them,we can get reasonable fitting values of basic cosmological parameters：ΩM=0.26 ＋0.04 -0.04,andΩΛ=0.82 ＋0.14 -0.16.

System error iterative identification for underwater positioning based on spectral clustering

The observation error model of the underwater acous-tic positioning system is an important factor to influence the positioning accuracy of the underwater target.For the position inconsistency error caused by considering the underwater tar-get as a mass point,as well as the observation system error,the traditional error model best estimation trajectory(EMBET)with little observed data and too many parameters can lead to the ill-condition of the parameter model.In this paper,a multi-station fusion system error model based on the optimal polynomial con-straint is constructed,and the corresponding observation sys-tem error identification based on improved spectral clustering is designed.Firstly,the reduced parameter unified modeling for the underwater target position parameters and the system error is achieved through the polynomial optimization.Then a multi-sta-tion non-oriented graph network is established,which can address the problem of the inaccurate identification for the sys-tem errors.Moreover,the similarity matrix of the spectral cluster-ing is improved,and the iterative identification for the system errors based on the improved spectral clustering is proposed.Finally,the comprehensive measured data of long baseline lake test and sea test show that the proposed method can accu-rately identify the system errors,and moreover can improve the positioning accuracy for the underwater target positioning.

BSEC Method for Unveiling Open Clusters and its Application to Gaia DR3:83 New Clusters

Open clusters(OCs) are common in the Milky Way, but most of them remain undiscovered. There are numerous techniques, including some machine-learning algorithms, available for the exploration of OCs. However, each method has its limitations and therefore, different approaches to discovering OCs hold significant values. We develop a comprehensive approach method to automatically explore the data space and identify potential OC candidates with relatively reliable membership determination. This approach combines the techniques of Hierarchical Density-Based Spatial Clustering of Applications with Noise, Gaussian mixture model, and a novel cluster member identification technique, color excess constraint. The new method exhibits efficiency in detecting OCs while ensuring precise determination of cluster memberships. Because the main feature of this technique is to add an extra constraint(EC) for the members of cluster candidates using the homogeneity of color excess,compared to typical blind search codes, it is called Blind Search-Extra Constraint(BSEC) method. It is successfully applied to the Gaia Data Release 3, and 83 new OCs are found, whose color–magnitude diagrams(CMDs) are fitted well to the isochrones. In addition, this study reports 621 new OC candidates with discernible main sequence or red giant branch. It is shown that BSEC technique can discard some false negatives of previous works, which takes about three percentage of known clusters. It shows that as an EC, the color excess(or twocolor) constraint is useful for removing fake cluster member stars from the clusters that are identified from the positions and proper motions of stars, and getting more precise CMDs, when differential reddening of member stars of a cluster is not large(e.g., ΔE(G_(BP)-G_(RP)) < 0.5 mag). It makes the CMDs of 15% clusters clearer(in particular for the region near turnoff) and therefore is helpful for CMD and stellar population studies. Our result suggests that the color excess constraint is more appropriate for clusters with small differential reddening, such as globular clusters or older OCs, and clusters that the distances of member stars cannot be determined accurately.

Study of 26 Galactic Open Clusters with Extended Main-sequence Turnoffs

Recent studies indicate that some Galactic open clusters(OCs)exhibit extended main-sequence turnoff(eMSTO)in their color–magnitude diagrams(CMDs).However,the number of Galactic OCs with eMSTO structures detected so far is limited,and the reasons for their formation are still unclear.This work identifies 26 Galactic OCs with undiscovered eMSTOs and investigates the causes of these features.Stellar population types and fundamental parameters of cluster samples are acquired using CMD fitting methods.Among them,the results of 11 OCs are reliable as the observed CMDs are well-reproduced.We propose the crucial role of stellar binarity and confirm the importance of stellar rotation in reproducing eMSTO morphologies.The results also show that the impact of age spread is important,as it can adequately explain the structure of young OCs and fit the observed CMDs of intermediate-age OCs better.

Effect of Varicocelectomy on Semen Parameters of Men Seeking Infertility Treatment in Tamale, Ghana

The study aimed to determine the effect of microsurgical sub-inguinal varicocelectomy on semen parameters among men seeking infertility treatment in Ghana. This was an intervention study conducted at Tamale Teaching Hospital in the Tamale Metropolis from September 2017 to August 2021. The study involves two groups;the surgery group (n = 75) and the observed group (n = 63). Duplicate semen samples (mean values adopted) were collected at the onset and assessed according to the criteria established by World Health Organization (WHO), 2010. Varicocelectomy was performed for the surgery group and no intervention was given to the observed group. The two groups were followed for 180 days and repeated semen samples were collected and analyzed. The data was computed using GraphPad Prism (v8.0) at an alpha of 0.05. All the men had varicocele and were aged between 46.0 and 67.0 years old. There was no difference between semen parameters among the two groups before the surgery. However, after 180 days of follow-up, all of the semen parameters significantly improved in the surgery group (p < 0.0001), while sperm concentration (p = 0.0068), progressive motility (p = 0.0281), and normal sperm morphology (p = 0.0015) decreased in the observed group. The surgery group had an overall percent increase in total sperm count (840.7%;p = 0.0197), sperm concentration (582.1%;p = 0.0125), total viable sperms (155.2%;p < 0.0001), and normal sperm morphology (110.9%;p < 0.0001) while immotile sperms (-51.71%;p < 0.0001) reduced. A pregnancy rate of 25.3% (19/75) was reported among the surgery group but none was reported among the observed group after 180 days. Microsurgical sub-inguinal varicocelectomy improves semen parameters and hence effective treatment of infertile men with a clinically palpable varicocele. It is recommended to use this choice for similar patients, however, further studies with a larger sample size are needed to provide more evidence to recommend this therapy.

Syntheses，Structures and Spectroscopic Properties of Mo（W）－Cu－S－Cluster Compounds with Dialkyldithiocarbamate Ligands

This paper presents the synthetic and structure studies of molybdenum（tungsten）-copper-sulphur-dialkyldithiocarbamate cluster compounds.The reactions of（M=Mo,W;n=0,2）,CuCl,and R2dtc￣-（R2=Me2,Et2,C4H8,C5H10） yield a series of tetra-,hexa-,and heptanuclear cluster compounds.Their spectroscopic properties and the synthetic reaction mechanism are discussed.