"The effect of the administration of mepivacaine hydrochloride on the histological and electronmicroscopical appearance of the rat testis "

) Int his investigation the histology and histochemistry of the testes of albino rats receiving Mepivacaine-HCL solution of different doses and concentrations were studied using both light and electron microscopes. The testes of treated animals showed different degrees of damage. The severity of the damage was classified into "slightly", "partially" and "severely" damaged tubules. Vacuolation was seen in the "slightly" damaged tubules by many investigators who gave different explanations about how and what causes vacuole formation. In this study, a new hypothesis was introduced. The late spermatids were readily damaged after Mepivacaine-HCl administration. Then, the carly spermatids showed different degrees of damage and degeneration; the mitochondria appeared extremely electron dense and scattered in the cytoplasm instead of being close to the cell membranes. The primary spermatocytes were the next in order of sensitivity. A marked morphological alongation of the cytoplasm of these cells was usually seen. Their mitochondria showed a distant swelling and cup-shaped mitochondria were also found. These were not typical of germinal cells of control testes. The secondary spermatocytes showed marked destruction in some parts of the cytoplasm and the nuclear membrane appeared bulging into the cytoplasm. Their mitochondria showed disruption and fusion of the membranes. The light microscope did not determine the extent of damage of spermatogonia. However, the electron microscope showed slight changes of the Golgi apparatus and mitochondria after administration of Mepivacaine-HCl. The mitochondria of spermatogonia were frequently swollen and their cristae were disintegrating and coalesoing together forming a condensed electron dense bodies. Sertoli cells were the cell type most resistant to drug administration. The boundary tissue of tubules, "partially" and "severely" damaged, showed a marked increase in thickness at the light microscope level. At the electron microscope level, the boundary tissue could be resolved into the four layers which became highly folded. Many extremely large lipid droplets were present in the seminiferous epithelium of the treated animals as well as in the interstitial cells. Sinoe Mepivacaine-HCl has a vasoconstructor effect and spermatogenesis is very sensitive to reduced blood flow, it could be concluded that the injurious effect of the administration of Mepivacaine-HCl intraperitoneally is probably due to reduced blood flow to the testes

Scotogenic A4A_4 Neutrino Model for Nonzero θ13\theta_{13} and Large δCP\delta_{CP}

Assuming that neutrinos acquire radiative seesaw Majorana masses through their interactions with dark matter, i.e. scotogenic from the Greek 'scotos' meaning darkness, and using the non-Abelian discrete symmetry $A_4$, we propose a model of neutrino masses and mixing with nonzero $\theta_{13}$ and necessarily large leptonic CP violation, allowing both the normal and inverted hierarchies of neutrino masses, as well as quasi-degenerate solutions.Comment: 12 pages, 12 figure

Higgs Effects in Neutrino Physics and Heavy Quark Systems

This work presents a study of the effects of multi-Higgs doublets on the properties of neutrino sector and heavy quark systems. The phenomenological implications of multi-Higgs models, which contain multi-Higgs doublets, in the neutrino and quark sector are discussed in this dissertation. The two-Higgs-doublet model (2HDM), in which two Higgs doublets are introduced, is the simplest extension to the scalar sector of the standard model (SM). A new boson state was recently seen in the CMS (Compact Muon Solenoid) and ATLAS (A Toroidal LHC Apparatus) experiments at the LHC (Large Hadron Collider). We investigate the multi-Higgs models contributions in understanding various phenomena in the neutrino sector. Introducing a model to explain the neutrino oscillation phenomenon within the framework of multi-Higgs doublets is considered. We introduce different flavor symmetries in the lepton sector and study the phenomenological consequences in both the scalar and lepton sectors. The leptonic mixing in the symmetric limit can be, among other structures, the bi-maximal (BM) or the tri-bimaximal (TBM) mixing. We find that a mixing model with 2-3 flavor symmetry can explain the nonzero θ13 measurements. In our study, neutrino masses were proposed where its smallness is not due to the seesaw mechanism, i.e. not inversely proportional to some large mass scale. It comes from a one-loop mechanism with dark matter in the loop consisting of singlet Majorana fermions within a model with A4 flavor symmetry. A relevant point of interest in the neutrino sector is the study of the nonstandered interactions and its implications to neutrino oscillation. Here, we introduce the nonstandard interaction effects at the detectors of neutrino oscillation experiments and the impact of extracting the neutrino mixing angles is studied. The extractions of the atmospheric mixing angle θ23 rely on the standard model cross sections for ντ + N → τ- + X in ν τ appearance experiments. Corrections to the cross sections from the charged Higgs and W’ contributions modify the measured mixing angle. We include form factor effects in the new physics calculations and find the deviations of the mixing angle. The quark sector has enriched our knowledge of particle physics. Lots of new theories and discovering new attributes of particles have been done in the quark sector. Therefore, we study the decay channel of the quarkonium η b → τ+ τ– to search for the existance of an additional Higgs field or a new gauge boson. We estimate the standard model branching ratio for this decay to be ∼ 4 × 10 –9. We show that considerably larger branching ratios, up to the present experimental limit of ∼ 8 percent, is possible in models with a light pseudoscalar or a light axial vector state. Also, in this dissertation we study the forward-backward asymmetry AFB in the top quark pair production in the t t¯ rest frame. In this work we seek for a new gauge boson to accommodating the CDF (Collider Detector at Fermilab) measurement of the AFB, which has a deviation from the next-to leading order (NLO) SM prediction. A u → t transition via a flavor-changing Z’ can explain the data. We consider the most general form of the tuZ’ interaction, which includes vector-axial vector as well as tensor type couplings, and study how these couplings affect the top forward-backward asymmetry

An investigation of the relationships between Libyan EFL lecturers’ beliefs about the teaching and learning of reading in English and their classroom practices in Libyan universities

Although the significant influence of lecturers’ beliefs on their practices in the classroom is well known, not much is known about teachers’ beliefs and the extent to which they influence reading instructional techniques (Woods, 2006). Furthermore, no comprehensive studies have been carried out in the context of Libyan universities, where lecturers in English are non-native speakers of the language and have only minimal resources and limited access to published research and scholarship regarding this topic. The present qualitative study aims to fill this gap in knowledge, considering contextual factors such as limited access to expert knowledge, a fixed curriculum, time restrictions and the isolation of lecturers, in an analysis of the beliefs that lecturers in English hold and the correspondence between these beliefs and their teaching practices. The study explores the factors that shape lecturers’ beliefs and examines the relationship between their beliefs and practices. Twenty-three unstructured observation sessions were conducted with male and female lecturers teaching English reading. Each class was observed 3 times, giving a total of 69 classes. In addition, semi-structured interviews were conducted with twenty male and female lecturers. The observation and interview data were analysed inspired by grounded theory. The findings revealed that lecturers held a variety of beliefs, and these did not always inform their practices in the classroom. This study provides a more in-depth understanding of the multifaceted relationship between what lecturers believe and what they practise regarding the teaching of English reading. The study acknowledges the themes of the differences and similarities between lecturers’ beliefs and practices, with observations such as ‘lecturers knew, but did not do’; ‘lecturers did, but were not aware that they did’; and ‘lecturers did, and they knew’. In addition, the study demonstrates that correspondence between beliefs and practices does not necessarily result in positive pedagogical consequences, while a lack of such correspondence may not have negative results. The research also reveals that, irrespective of the relationships between beliefs and practices, the underpinning rationales are linked to the complex relationship between lecturers’ beliefs and practices and a range of other factors. The findings of this study could be of benefit to both current and future EFL lecturers of reading and should also provide directions for further research in this field

Phenomenology of Λb→Λcτνˉτ\Lambda_b \to \Lambda_c \tau \bar{\nu}_{\tau} using lattice QCD calculations

In a recent paper we studied the effect of new-physics operators with different Lorentz structures on the semileptonic $\Lambda_b \to \Lambda_c \tau \bar{\nu}_{\tau}$ decay. This decay is of interest in light of the $R({D^{(*)}})$ puzzle in the semileptonic $\bar{B} \to D^{(*)} \tau {\bar\nu}_\tau$ decays. In this work we add tensor operators to extend our previous results and consider both model-independent new physics (NP) and specific classes of models proposed to address the $R({D^{(*)}})$ puzzle. We show that a measurement of $R(\Lambda_c) = {\cal B}[\Lambda_b \to \Lambda_c \tau \bar{\nu}_{\tau}] / {\cal B}[\Lambda_b \to \Lambda_c \ell \bar{\nu}_{\ell}]$ can strongly constrain the NP parameters of models discussed for the $R({D^{(*)}})$ puzzle. We use form factors from lattice QCD to calculate all $\Lambda_b \to \Lambda_c \tau \bar{\nu}_{\tau}$ observables. The $\Lambda_b \to \Lambda_c$ tensor form factors had not previously been determined in lattice QCD, and we present new lattice results for these form factors here.Comment: 44 pages, 105 figure