Two series of polyhedral fundamental domains for Lorentz bi-quotients

The main aim of this paper is to give two infinite series of examples of Lorentz space forms that can be obtained from Lorentz polyhedra by identification of faces. These Lorentz space forms are bi-quotients of the form $\Gamma_1\backslash G/\Gamma_2$, where $G=\widetilde{\operatorname{SU}(1,1)}\cong\widetilde{\operatorname{SL}(2,{\mathbb R})}$ is a simply connected Lie group with the Lorentz metric given by the Killing form, $\Gamma_1$ and $\Gamma_2$ are discrete subgroups of $G$ and $\Gamma_2$ is cyclic. A construction of polyhedral fundamental domains for the action of $\Gamma_1\times\Gamma_2$ on $G$ via $(g,h)\cdot x=gxh^{-1}$ was given in the earlier work of the second author. In this paper we give an explicit description of the fundamental domains obtained by this construction for two infinite series of groups. These results are connected to singularity theory as the bi-quotients $\Gamma_1\backslash G/\Gamma_2$ appear as links of certain quasi-homogeneous $\mathbb Q$-Gorenstein surface singularities, i.e.\ the intersections of the singular variety with sufficiently small spheres around the isolated singular point.Comment: 16 pages, 6 figures, 2 tables of figure

Diagnostic use of hair analysis for the detection of misuse of amfetamines and cannabinoids

The purpose of this study was to develop a single method to analyse drugs in hair and to apply this to case samples received from The Security Forces Hospital, Saudi Arabia. First of all, mass fragments and retention times for amfetamines and cannabinoids were identified by GC-MS using derivatization agents, PFPA/ethyl acetate (2:1 v/v) and PFPA / PFPOH (1:0.75 v/v) for amphetamines and cannabinoids, respectively. The results showed good peak shape, good chromatographic resolution and good sensitivity for amfetamine (AF), methamphetamine (MA), 3,4-Methylenedioxyamfetamine (MDA), 3,4-Methylenedioxymethamfetamine (MDMA), 3,4-Methylenedioxyethylamfetamine (MDEA), Δ9-tetrahydrocannabinol (Δ9-THC) and 11-nor-9-carbody- Δ9-tetrahydrocannabinol (Δ9-THC-COOH) compounds. The comparison of the efficiency of four different pre-treatment methods (enzymatic, alkaline, acid and methanol) to extract AF, MA, MDA, MDMA, MDEA, Δ9THC and Δ9-THC-COOH from hair samples obtained from known amfetamines and cannabinoid abusers was investigated. The preliminary results demonstrated difficulty with the cannabinoids recovery and the lower concentration of standards were not detected using any of the pre-treatment methods. As a result of the poor cannabinoids recovery, only the amfetamines were investigated. For the comparison study, only one hair sample positive for amphetamine was available so the pre-treatment comparison study was based on the recovery of AF using the four pre-treatment methods. The positive hair sample was separated into portions and pre-treatment methods, alkaline (1M NaOH), β-Glucuronidase (helix pomatia), methanol (MeOH) and acid (0.1M HCI) were used on these and compared. The best recovery for amphetamine was obtained using the β-glucuronidase pre-treatment method and this extract was also found to be cleaner than the alkaline and methanol pre-treatments. Β-glucuronidase pre-treatment was selected as the method of choice for the extraction of amphetamine content in hair. The method was validated to include linearity, recovery, intra- and inter-day precision, limit of quantitation (LOQ) and limit of detection (LOD) for all five amphetamine compounds. The method was shown to be reliable and robust for these substances. The stability of AF in hair was investigated to assess the validity of analysing hair samples for the presence of AF in victims of drowning. Ten amphetamine positive hair samples were submerged in fresh and sea water for different periods of time. The drug concentrations in the samples were monitored over a period of 8 weeks. Hair samples were analysed using the validated method. The results showed a significant decrease of amphetamine in hair with the time submerged in sea water. Fresh water had a much less significant effect over the study period. The validated method was successfully applied to 16 case samples obtained for living volunteers with a known history of fenethylline (AF precursor) abuse and 6 post-mortem case samples where amfetamines had been detected in the post-mortem blood

Cultural Awareness in Nuclear Security Programs: A Critical Link

Nuclear security programs that offer training and capacity building opportunities to practitioners working in nuclear facilities play a central role in strengthening the global nuclear security architecture. There is often a significant divide, however, between both the development of these programs and their implementation, and between the programs’ intended and actual outcomes. As this article will argue, this disconnect can often be attributed to an absence of cultural awareness and an inability for internationally-designed programs to effectively resonate with local audiences. Accordingly, the importance of the role of cultural awareness in implementing nuclear security programs will be assessed, and its applications in the Jordanian context will be presented

Evaluation of Groundwater Quality in Shallow Aquifers Under Cultivated Lands at Al Oha Area, United Arab Emirates

To assess the impact of application of chemical fertilizers in agriculture on the Quaternary aquifer at AI Oha area, United Arab Emirates, 76 groundwater samples were collected during February 1995 - March 1996. Samples were analyzed for major, minor and trace chemical constituents in the Food Control Laboratory, Abu Dhabi. The Total Dissolved Solids (TDS) of collected samples varied between 500 milligrams per liter (mg/l) in the east and 3,500 mg/l in the west. Except for bicarbonate ion (HC03-), concentration of major cations (Ca2+, Mg2+, Na+ and K+) and anions (CO32-, SO42- and Cl-) shows a general increase from east to west. The increase of salinity and concentration of all ions from east to west occurs in the direction of groundwater flow, where ion-depleted water from recharge area in the east becomes progressively loaded with more ions towards discharge areas in the west. Concentration of nitrate ion (NO3- in groundwater within the study area during February 1995 - March 1996 remained below the limits recommended by the World Health Organization (WHO) for drinking water (45 mg/l as NO3- or 10 mg/l as NO3--N). Phosphate ion (PO4-) shows trace concentrations in groundwater within the study area, averaging 0.8 mg/l. With the exception of few local anomalies, concentrations of iron (Fe), manganese (Mn), lead (Pb), zinc (Zn), copper (Cu), cobalt (Co) and chromium (Cr) shows a general increase from east to west. Based on the above results, there is no reason to believe that the chemical fertilizers used on farm lands at AI Oha area has adversely affected groundwater in the Quaternary aquifer

Human Resource Practices and Innovativeness: A Conceptual Paper

Purpose: The purpose of this study is to review and produce a set of propositions about the function of human resource practises and innovativeness in a business environment.   Implications of research: Growing worldwide rivalry, extremely unpredictable markets, and even greater customer expectations have resulted as a result of the globalisation of the world, making it important for enterprises to be open to the possibility of innovation.   Findings: According to the findings of this research, a paradigm for understanding the relationship between human resource practises and innovativeness, as well as the moderating effect of innovation capability, is proposed.   Originality/Value: This document contains a series of propositions that constitute an empirically driven research agenda, as well as descriptions of the correlations between the focus variables that are given to improve the understanding of the audience in a business setting

Fundamental domains for left-right actions in Lorentzian geometry

We consider tilde{G} = tilde{SU}(1, 1) = tilde{SL}(2,R). The aim of this thesis is to compute the fundamental domains for two series of groups of the form tilde{Gamma}_1 X tilde{Gamma}_2 acting on tilde{G} by left-right multiplication,i.e. (g, h) . x = gxh^{−1}, where tilde{Gamma}_1 and tilde{Gamma}_2 are discrete subgroups of tilde{G} of the same finite level and tilde{Gamma}_2 is cyclic. The level of a subgroup tilde{Gamma} in tilde{G} is defined as the index of the group tilde{Gamma} intersection with Z(tilde{G}) in the center Z(tilde{G}) =� Z. From computing the fundamental domain we can describe the biquotients tilde{Gamma}_1 \ tilde{G} / tilde{Gamma}_2 which are diffeomorphic to the links of certain quasihomogeneous Q-Gorenstein surface singularities, i.e. the intersections of the singular variety with suffi�ciently small spheres around the isolated singular point as shown in [16]

A review of cloud oriented mobile learning platform and frameworks

With the continued growth of mobile devices usage, wireless communications improvement, and cloud computing evolution, many educational institutions around the world, especially universities and colleges, began to provide their students with mobile learning systems based on cloud computing. The widespread, ubiquitous, and flexible natures of mobile devices make mobile learning an attractive alternative in education, particularly when integrating it with cloud computing which is the up-to-date technology that delivers computing hardware and software as services. However, the participatory between mobile learning and cloud computing as a cloud based mobile learning (CBML) becomes one of the important methods in the learning process. Many researches have attempted to combine the unique features of CBML in a form of frameworks. These frameworks have been designed to identify, categorize, or evaluate the major components of the CBML system. This paper is an attempt to identify the important role of cloud computing technology in mobile learning, investigate the main advantages and limitations of CBML systems, and explore the previously designed CBML frameworks