Transmission of Nocardia farcinica by two Ixodid species

The cultural, morphological and pathogenic characteristics of Nocardia farcinica were studied.Guinea pigs were susceptible to Nocardia farcinica, showing typical lesions following injections with cultures or infected tick materials.Rabbits readily acquired a generalized infection with Nocardia farcinica but only a small proportion of those so injected developed lesions.Generalized Nocardia farcinica infections did not result from minor skin traumata (pin -pricks and scarification) made in rabbits' ears and guinea pigs' backs which had previously been painted with cultures of the organism, and neither did they result when ticks were fed on surfaces so treated.The feeding performance and developmental periods of Amblyomma variegatum and Hyalomma anatolicum excavatum were also precisely studied.Larvae and nymphs of Amblyomma variegatum acquired Nocardia farcinica infection from rabbits and, at periods of up to nine weeks, transmitted these infections to other rabbits when feeding as the subsequent instars. Trials proved that this period of retention of transmissible infection can extend up to 33 weeks.Nymphs and adults of Amblyomma variegatum showed their ability to retain transmissible infection under various environmental conditions.Larvae and nymphs of Hyalomma anatolicum excavatum acquired Nocardia farcinica infection from rabbits and, at periods of up to eight weeks, transmitted the infection to other rabbits when feeding as the following instars. However, subsequent trials showed that Hyalomma anatolicum excavatum cannot retain naturally transmissible Nocardia farcinica infection for longer periods.Trans-ovarial transmission was not achieved with either species.These clear demonstrations of the trans-stadial transmission of the bovine farcy organism confirmed the existence of an epidemiological feature which has previously only been suspected

The SQ universality of some small cancellation groups

PhDA group G is a small cancellation group if, roughly, it has a presentation G= <A; R with the property that for any pair r, s of elemets of R either r=s1 or there is very little free cancellation in forming the product rs. The classical example of such a group is the fundamental group of a closed orientable 2-manifold of genus k which has a presentation k G=< al, bl, ..., ak, bk; 'TT \ai, bi' i=1 A countable group G is SQ-universal if every countable group can be embedded =in some quotient of G. The obvious example of SQ-universal group is the free group of rank 0. This work is a study of the SQ-universality of some small cancellation groups. A theory of diagrams is investigated in some detail- to be used as a tool in this study. The main achievement in this work is the following two results: (1) With few exceptions a small cancellation group contains nonabelian free subgroups. ( The emphasis here is on the nature of the free generators. ) (2) A characterization of the S Q-universality of some small cancellation groups

Identify Some Morphorogical and Biological Study of Gar or Alligator Fish Atractosteus spatula (Lepisosteiformes : Lepisosteidae ) ( Lacepede ,1803 )

This study attempt to highlight some aspects and the vital characteristics of the Gar or Alligator fish, also known as the Atractosteus spatula. These aspects include some of the behavior characteristics in family and the pattern of nutrition, in addition to some Morphorogical and Biological features that characterize this species such as body shape, and the ear's bone, especially it was recorded for the first time in the Iraqi waters in 2017 within the extraneous fish on the Iraqi water environment. Keywords: Biological aspects, Morphological aspects, Gar fish, Alligator fish

Effect of Financial Independence on Reducing Risk of Financial Fragility

Purpose:This research aims to know and measure the impact of financial independence on financial fragility and to provide an applied knowledge framework that shows the relationship between these variables.   Theoretical framework:  and the research problem was represented in several questions, such as can financial independence reduce the financial fragility of the research sample companies?; and what is the level of financial independence and financial fragility of these companies?.   Design/methodology/approach: Financial and statistical methods were relied on using the (SPSS) and (Excel) software. To answer these questions, test hypotheses and analyze the relationship between independent and dependent variables , several conclusions were reached, the most important of which is financial independence when companies reduce their dependence on debt and increase their dependence on internal resources as a main source of financing. Based on the conclusions, a set of recommendations was reached. The most important of which is the attention to restructuring the sources of financing for companies with high financial fragility, which contributes to increasing financial stability and reducing financial risks to a minimum.   Findings: The research was based on a sample consisting of (6) industrial companies listed in the Iraqi Stock Exchange for the period from (2011-2020).   Research, Practical &amp; Social implications: The importance of the research lies in the fact that it has exploited the concepts of financial independence as it leads to reducing risks and assisting companies in reducing financial risks and reaching the required levels of performance, growth and continuity in a highly complex, unstable and limited environment, as well as contributing to urging companies to reconsider financial resources, and ways to benefit from it, which contributes to reducing costs and risks and increasing profitability.   Originality/value: The importance of the current research is highlighted by delving into very important topics for industrial companies, as the concepts of financial fragility and financial independence are of increasing importance in the current era, especially in light of the competitive environment, high costs and difficulty in obtaining financial resources

Nonlinear Stability Prediction of Multibit Delta-Sigma Modulators for Sinusoidal Inputs

This paper proposes a novel algorithm that can be integrated with various design and evaluation tools, to more accurately and rapidly predict stability in multi-bit delta-sigma (Δ-Σ) modulators. Analytical expressions using the nonlinear gains from the concept of modified nonlinearity in control theory are incorporated into the mathematical model of multi-bit Δ-Σ modulators to predict the stable amplitude limits for sinusoidal input signals. The nonlinear gains lead to a set of equations which can numerically estimate the quantizer gain as a function of the input sinusoidal signal amplitude. This method is shown to accurately predict the stable amplitude limits of sinusoids for 2nd-, 3rd-, 4th-, 5th- and 6th-order 3- and 5-level mid-tread quantizer based Δ-Σ modulators. The algorithm is simple to apply and can be extended to midrise quantizers or to any number of quantizer levels. The only required input parameters for this algorithm are the number of quantizer levels and the coefficients of the noise transfer function

System and circuit level design and analysis of a 16-bit sigma-delta ADC for a TETRA-2 network mobile station application

This paper outlines a comprehensive design evaluation for development of a 16-bit Sigma-Delta (Σ-Δ) Analog-to-Digital Converter (ADC) for TETRA-2 Network Mobile Station (MS). A step-by-step design approach is described commencing from system-level evaluation leading to the circuit design, which would serve as a useful reference to designers involved with development of ADCs for wireless equipment

Accurate stability prediction of single-bit higher-order Δ-Σ modulators for Speech Codecs

Present approaches for predict of Delta-Sigma (Δ-Σ) modulators are mo DC inputs. This poses limitations as pract of Δ-Σ modulators involve a wide range than DC such as speech, audio and multip the case for synthetically generated spee any other signal, through the appropriat multiple sinusoids. In this paper, a quasi linear model that accurately predicts stability of single-loop 1-bit higher order (Δ-Σ) modulators for mulitple sinusoids is given. The results of this paper would enable optimization of the design of higher-order single-loop (Δ-Σ) modulators with increased dynamic ranges for various applications that deploy multiple sinusoidal inputs, as well as any general input signal constructed from multiple sinusoids

Stability analysis of higher-order delta-sigma modulators using the describing function method

The aim of this paper is to determine the stability of higher-order /spl Delta/-/spl Sigma/ modulators using the describing function method. The maximum stable input limits for third-, fourth- and fifth-order Chebyshev Type II based /spl Delta/-/spl Sigma/ modulators are established. These results are useful for optimising the design of higher-order /spl Delta/-/spl Sigma/ modulators

Tonality index of sigma-delta modulators: a psychoacoustics model based approach

This paper involves the development of a more accurate tonality index using Psychoacoustic techniques. This tonality measure will be especially relevant for quantifying the audibility of Δ-Σ modulators whose output spectra contain low amplitude tones. This tonality index will be very useful for the design and evaluation of Δ-Σ modulators circumventing the need to build a modulator prototype

Stability Analysis of Higher-Order Delta-Sigma Modulators for Dual Sinusoidal Inputs

The aim of this paper is to determine the stability of higher-order Δ-Σ modulators for sinusoidal inputs. The nonlinear gains for the single bit quantizer for a dual sinusoidal input have been derived and the maximum stable input limits for a fifth-order Chebyshev Type II based Δ-Σ modulators are established. These results are useful for optimising the design of higher-order Δ-Σ modulators