Level Of Statistical Errors Research Articles

Length‐weight relationships of Baikal omul <i>Coregonus migratorius</i> during the feeding season in the Selenga area, Russia

Aim . To refine the LWR coefficients for the Baikal omul Coregonus migratorius (Georgi, 1775). Material and Methods . The data set (number of fish, standard length ( SL ), weight ( W ), sex and morpho‐ecological group (MEG) for the study of the LWR coefficients were taken from the Baikal Omul database. The analysis includes data from 3,091 specimens of Baikal omul, collected in May to June 2003, 2006 and 2007 and in September 2004 in the area adjacent to the delta of the Selenga River. The construction of regression models of LWR was carried out for all data without taking into account gender and MEG. In addition, regression models of LWR data were obtained, grouped by gender and belonging to a certain MEG. Results . Dependencies with close values of the coefficients of the power function are obtained. There were no significant differences between fish of different sexes and MEG, the coefficients differing at the level of statistical error. It is shown that the LWR in fish during feeding periods of different years is quite stable. Conclusion . We offer the equation W=10,9(SL dm ) 3.02 that has acceptable coefficients for C. migratorius resource estimations during feeding period without carrying out controlled fishing.

ІННОВАЦІЙНИЙ РОЗВИТОК ЛІСОВОГО КОМПЛЕКСУ РЕСПУБЛІКИ КОМИ: СТАН І ПЕРСПЕКТИВИ

Global manufacturers of timber products and specialized research institutes are actively developing innovative materials and improving production processes. The fastest growing groups include innovative packaging materials, innovative building materials, biodegradable polymers and biofuels. The aim of the article is to form a theoretical and methodological basis for the innovative development of the forestry complex of the Komi Republic. The subject of the research is theoretical and methodological aspects of innovative development of the forestry complex. Methods used in the study: historical method, methods of verification of theoretical positions (morphological analysis of the content and relationship of categories, principles and laws, assessment of the correspondence of historical facts to theoretical hypotheses), methods of analysis and synthesis, induction and deduction, logical method (hypothetical and axiomatic approaches), comparison method. Research hypothesis. The innovative development of the forestry complex in Russia is associated with forest chemistry. In particular, tall oil rosin and tall oil fatty acids in the markets of Russia and Asia are considered the most priority segments for Russian manufacturers. Presentation of the main material. Analysis of the current state of the forestry complex of the Komi Republic revealed an extremely low level of innovation activity. Over the years after the collapse of the Soviet Union, development proceeded along the extensive path of increasing the production and export of forest products of primary and secondary levels of redistribution, and the share of innovative products in the commodity and industry structure was measured at the level of statistical error. Originality and practical value of the research. The production of innovative products of the second generation is a promising direction for the development of the timber processing industry in the Komi Republic. The main ones are: bioconversion of cellulose-containing raw materials; biomass torrefaction technology based on plant waste; production of sulphate turpentine; highly active preparations for agriculture from pine needles. Conclusions of the study. It is planned to implement these directions by increasing the output of products with high added value, organizing new production of innovative products, commissioning medium and small innovative enterprises for the production of wood flour, biosorbents and other products, and developing regional wooden housing construction.

DETERMINATION OF CHEWING EFFICIENCY IN PATIENTS WITH RESTORED TOOTH CROWN PART

Supporting teeth preservation at the restoration of dentition defects with the help of fixed porcelain fused metal dentures is considered one of the most important issues of prosthodontics.
 Margin line preparation strategies are still disputable nowadays. In most cases preparation is confined to the ledge creation. Its function is to provide a smooth transition of orthopedic restoration to a tooth root and prevent the traumatization of marginal paradontium.
 These issues are gaining a momentum when the possibility of manufacturing fixed prosthesis with the use of partially or completely ruined teeth with the preserved root as a support appears.
 Since the opportunities of thermal method for gingiva retraction and marginal line formation around the supporting teeth are not studied enough in modern scientific sources, our research aims to define the mastication efficiency state in patients of sample groups after the fixation of dentures on the supporting teeth prepared for prosthesis with the help of diathermocoagulation and mechanical retraction.
 The authors of the article have determined the mastication efficiency in the patients with the restored tooth crown. Altogether 54 patients of two sample groups aged from 20 to 60 years and above with completely ruined tooth crowns were examined. Their soft tissues around the supporting teeth were prepared for the fixed prosthesis manufacturing.
 The first sample group involved 29 patients that made up 53.7% of general studied population. Their supporting teeth gingiva margins were retracted with the help of diathermocoagulation while preparing them for the fixed dentures. While the gingiva margins of the patients of the second sample group, consisting of 25 people (46.3% of general studied population), were retracted with the help of cotton Ultrapak cord, produced by Ultradent (the USA). It is offered in several size options.
 Mastication efficiency state after prosthesis was determined with the help of mastication test (Ukrainian Utility Patent # 94841). In this case, mastication index was the main diagnostic tool. It was received with the help of computer analysis of digital samples in software “Adobe Photoshop Extended”.
 The analysis of the dynamics of mastication test indices of the patients of sample group 1 delivered typical results. In a week after the fixation of fixed porcelain fused metal dentures, the reduction of the mean value of mastication test index by 0.2 was fixed. The verification of these changes according to the statistical significance showed positive result (at p = 0.0004). At the same time, the verification of the changes, occurred during the period from the 7th to the 30th day after the fixation of dentures in patients of sample group 1, with the help of Wilcoxon test showed that at p = 0.9 the reduction of the mean value to 5.148 had no statistical significance.
 While the dynamics of mastication test changes in sample group 2 looked as follows. The reduction of the mean values of mastication test index from 5.184 to 5.112 was observed. So, the spread between the values received before the retraction and in seven days after crown fixation made up 0.072. The conducted statistical verification of these changes (at p = 0.01) proved their statistical significance. In contrast, the collation of the indices received after seven days of denture fixation and in 30-days period after it (from 5.112 to 5.132) at p = 0.961 demonstrated changes at the level of statistical error.
 According to the received research results, prosthesis with the fixed porcelain fused metal dentures promotes patients’ mastication efficiency restoration. That is traced in the reduction of the mastication test index values received after the 7th day of crown fixation in both sample groups. It should be noted here, that statistically significant difference between the indices of the patients of sample group 1 and 2 was not found. On the 30th day of denture fixation, mastication efficiency indices remained almost the same.

Finite size effect on vector meson and baryon sectors in 2+1 flavor QCD at the physical point

We investigate the finite size effect on the vector meson and the baryon sectors using a subset of the "PACS10" configurations which are generated, keeping the space-time volumes over (10 fm$)^4$ in 2+1 flavor QCD at the physical point. Comparing the results on (5.5 fm$)^4$ and (10.9 fm$)^4$ lattices the ground states of octet baryons , which are stable on the lattice, show no finite size effect within less than 0.5% level of statistical errors. For those of vector mesons, which are unstable on the lattice, we observe that the effective masses are well below the experimental resonance levels both on (5.5 fm$)^4$ and (10.9 fm$)^4$ lattices. For the decuplet baryon sector we have found that the time dependence of the effective mass looks quite similar to that for the vector meson sector including the $\Omega$ baryon channel. We discuss its origin due to a possible mixing with the nearby multihadron states. Since the $\Xi$ baryon mass can be determined with the smallest ambiguity among the vector meson and the baryon masses, we use it together with the pion and kaon masses as the physical inputs to determine the physical point.

An improved on-the-fly global variance reduction technique by automatically updating weight window values for Monte Carlo shielding calculation

This paper presents an improved on-the-fly global variance reduction (GVR) method for Monte Carlo radiation shielding calculations. This method generates the weight window (WW) mesh internally in the Monte Carlo (MC) code, and updates automatically the WW value on-the-fly as the particle flux of a mesh element has a certain level of statistical error. This method has many advantages, such as, it does not depend on third party codes; it only needs one MC run to obtained the WW mesh together with the global flux map; and it has no limitation on the source definition and particle types. In addition, a method to deal with long history problem, which is caused by excessive splitting of tracks, is proposed in this paper. The on-the-fly GVR method has been implemented in the MCNP code and verified using a simple 2D model and the ITER benchmark model. The results show significant acceleration effects on the MC shielding calculation against analog simulations.

Utilization of Statistical Methods in Microbiological Research

Most papers published in medical journals contain analyses that have been carried out without any help from a statistician. Although nearly all medical researchers have some acquaintance with basic statistics, there is no easy way for them to acquire insight into important statistical concepts and principles. There is also little help available about how to design, analyze, and write up a whole research paper. A high level of statistical errors has been noted in several reviews of journal articles and has caused much concern. It has been suggested that comprehensive statistical guidelines could help by making medical researchers more aware of important statistical principles, and by indicating what information ought to be supplied in a paper.

Anomalous Small Angle X-Ray Scattering Simulations: Proof of Concept for Distance Measurements for Nanoparticle-Labelled Biomacromolecules in Solution

Anomalous small angle X-ray scattering can in principle be used to determine distances between metal label species on biological molecules. Previous experimental studies in the past were unable to distinguish the label-label scattering contribution from that of the molecule, because of the use of atomic labels; these labels contribute only a small proportion of the total scattering signal. However, with the development of nanocrystal labels (of 50–100 atoms) there is the possibility for a renewed attempt at applying anomalous small angle X-ray scattering for distance measurement. This is because the contribution to the scattered signal is necessarily considerably stronger than for atomic labels. Here we demonstrate through simulations, the feasibility of the technique to determine the end-to-end distances of labelled nucleic acid molecules as well as other internal distances mimicking a labelled DNA binding protein if the labels are dissimilar metal nanocrystals. Of crucial importance is the ratio of mass of the nanocrystals to that of the labelled macromolecule, as well as the level of statistical errors in the scattering intensity measurements. The mathematics behind the distance determination process is presented, along with a fitting routine than incorporates maximum entropy regularisation.

Comparison of antioxidant, anti-inflammatory, antimicrobial activity and chemical composition of aqueous and hydroethanolic extracts of the herb of Tropaeolum majus L.

The aim of this study was comparison of antioxidant, anti-inflammatory, and antimicrobial activity, as well as chemical composition of extracts of Tropaeolum majus L. herb. Aqueous and hydroethanolic extracts derived from dried and freeze-dried nasturtium herb, prepared both at room temperature and at 90°C, were studied. In the studies there were no significant differences between antioxidant activity of the extracts. All extracts showed scavenging activity against all the examined reactive species in a concentration-dependent manner. The strongest scavenging activity they showed against reactive nitrogen species, NO (SC50 4.54±0.26–10.90±1.39μg/mL) and ONOO− (SC50 2.49±1.50–6.37±1.86μg/mL). Among reactive oxygen species, they showed strong scavenging activity against H2O2 (SC50 14.90±3.91–38.63±9.28μg/mL). Scavenging activity against O2− was weaker, while against HClO the extracts showed very weak activity, practically at the level of statistical error. Against synthetic radical – DPPH scavenging activity of the tested extracts was negligible. The extracts demonstrated stronger antioxidant activity in ex vivo experiment on human neutrophils. The extracts showed no inhibitory activity on hyaluronidase, but at a concentration of 50μg/mL they inhibited the activity of COX1 by approximately 60%. Lack of antimicrobial activity of the extracts seems to be associated with a low content of benzyl isothiocyanate. The aqueous extracts were characterized by the presence of esters of quinic acid with cinnamic acids (chlorogenic acids, p-coumaroylquinic acids) and the presence of flavonoids. Meanwhile the hydroethanolic extracts were mainly rich in the above mentioned acid esters.

Determination of the Weak Axial Vector Couplingλ=gA/gVfrom a Measurement of theβ-Asymmetry ParameterAin Neutron Beta Decay

We report on a new measurement of the neutron β-asymmetry parameter A with the instrument Perkeo II. The main enhancements are the high neutron polarization of P = 99.7(1)% from a novel arrangement of supermirror polarizers and reduced background from improvements in beam line and shielding. The leading corrections were thus reduced by a factor of 4, pushing them below the level of statistical error and resulting in a significant reduction of systematic uncertainty compared to our previous experiments. We derive the β-asymmetry parameter A0 = -0.11972(45)(stat)((-44)(+32))(sys) = -0.11972((-65)(+53)) and the ratio of the axial vector to the vector coupling constant λ = gA/gV = -1.2761(12)(stat)((-12)(+9))(sys) = -1.2761((-17)(+14)).

Steady-State Simulation of Long-Range Dependent Queuing Processes

Long-range dependence was first noted in hydrology by H. E. Hurst from a study of the water levels of the Nile river which showed a tendency for a flood year to be followed by another flood year. Long-range dependent processes are relevant not only in telecommunication networks but also in such areas of scientific activity as econophysics, climatology, economics, environmental sciences, geology, geophysics, hydrology, computer science, and computer engineering. They provide good models of packet trac in telecommunication networks, for example, in local area networks and video trac, and good models of persistence analysis in econophysics, especially for short-term interest rates. In this paper, the eects of long-range dependence on the behaviors of queuing systems have been investigated. We have also investigated how the long-range dependence in arrival processes aects the length of sequential steady-state simulations being executed to obtain simulation results with the required level of statistical error. Our results show that the finite buer overflow probability of a queuing system with a long-range dependent input is much greater than the equivalent queuing system with a Poisson or a short-range dependent input process and that the overflow probability increases as the Hurst parameter approaches one.

2+1flavor lattice QCD toward the physical point

We present the first results of the PACS-CS project which aims to simulate 2+1 flavor lattice QCD on the physical point with the nonperturbatively $O(a)$-improved Wilson quark action and the Iwasaki gauge action. Numerical simulations are carried out at the lattice spacing of $a=0.0907(13)$fm on a $32^3\times 64$ lattice with the use of the DDHMC algorithm to reduce the up-down quark mass. Further algorithmic improvements make possible the simulation whose ud quark mass is as light as the physical value. The resulting PS meson masses range from 702MeV down to 156MeV, which clearly exhibit the presence of chiral logarithms. An analysis of the PS meson sector with SU(3) ChPT reveals that the NLO corrections are large at the physical strange quark mass. In order to estimate the physical ud quark mass, we employ the SU(2) chiral analysis expanding the strange quark contributions analytically around the physical strange quark mass. The SU(2) LECs ${\bar l}_3$ and ${\bar l}_4$ are comparable with the recent estimates by other lattice QCD calculations. We determine the physical point together with the lattice spacing employing $m_\pi$, $m_K$ and $m_\Omega$ as input. The hadron spectrum extrapolated to the physical point shows an agreement with the experimental values at a few % level of statistical errors, albeit there remain possible cutoff effects. We also find that our results of $f_\pi=134.0(4.2)$MeV, $f_K=159.4(3.1)$MeV and $f_K/f_\pi=1.189(20)$ with the perturbative renormalization factors are compatible with the experimental values. For the physical quark masses we obtain $m_{\rm ud}^\msbar=2.527(47)$MeV and $m_{\rm s}^\msbar=72.72(78)$MeV extracted from the axial-vector Ward-Takahashi identity with the perturbative renormalization factors.

The effect of capillary column diameter on the performance of thermal conductivity detectors

AbstractThe concentration sensitivity of a thermal conductivity detector (TCD) depends, among other factors, on the amount of sample mixture in the detector's sensing cell. Since the cell volume has to be appropriately matched with column diameter, it makes the concentration sensitivity of a TCD dependent on column diameter and, therefore, on the speed of gas chromatography. Through reduction of column diameter, higher speed tends to lead to a reduction in the concentration sensitivity of the cell. The factor which the most directly affects the concentration sensitivity of a TCD cell is the heat power conducted through the cell. The higher the power, the greater the sensitivity. The limit of detection of a TCD depends on the concentration‐sensitivity of its cell and on the level of statistical errors in the measurement. The errors increase with increasing analysis speed. As the column diameter is reduced, the errors cause additional worsening (on top of the decrease in concentration sensitivity) of the detection limit, dynamic range, and other performance characteristics of the TCD.

Influence of statistical errors on size distributions obtained from dynamic light scattering data. Experimental limitations in size distribution determination

The relationship between the level of statistical errors in a measured intensity autocorrelation function and the relative size distribution width uncertainty is estimated. The results of the Fourier analysis of statistical errors existing in measured autocorrelation functions indicate that the individual error course can be similar to the systematic distortion. This has been also confirmed experimentally. The problem of the baseline error is also discussed. It is shown that the baseline error is compensated in dynamic light scattering data during normalisation.