Distinguishing Chromatic Number of Random Cayley graphs

The \textit{Distinguishing Chromatic Number} of a graph $G$, denoted $\chi_D(G)$, was first defined in \cite{collins} as the minimum number of colors needed to properly color $G$ such that no non-trivial automorphism $\phi$ of the graph $G$ fixes each color class of $G$. In this paper, we consider random Cayley graphs $\Gamma(A,S)$ defined over certain abelian groups $A$ and show that with probability at least $1-n^{-\Omega(\log n)}$ we have, $\chi_D(\Gamma)\le\chi(\Gamma) + 1$.Comment: 11 page

The role of Cornichon (Cni) in axis formation in Drosophila

Summary During oogenesis, in Drosophila melanogaster, the exchange of signals between the oocyte and the surrounding follicle cells govern both the polarization of the maturing egg and the subsequent establishment of the future embryonic body axes. Gurken (Grk), a TGF-α-like molecule signaling twice from the oocyte to the overlying follicle cells brings about the polarisation of both axes, the anterior-posterior (AP) and the dorsal-ventral (DV). The signal is perceived by the Drosophila EGF receptor (DER) present in abutting follicle cells. Cornichon (Cni) is a small hydrophobic protein which is absolutely required for Grk signaling. Earlier studies, in the lab, has shown a protein-protein interaction between the ER-luminal domain of Cni and the juxtamembrane domain (JMD) domain of Grk. In this study, it has been shown that the subcellular localisation of Cni is in line with an ER to Golgi cycling function. By inducing Grk transit through the bulk flow pathway of cellular exocytosis it could be shown that the requirement for Cni in enrichment of Grk vesicles can be overcome. Grk secreted via the bulk flow pathway in absence of Cni is active and signals to the DER. This demonstrates that Cni function is restricted to the transport of Grk from the ER to the Golgi and is not required for modification and/or proteolytic activation of Grk. This mode of ligand trafficking is a new component of the EGF ligand regulatory system. cni is not only required in the oocyte, it has also a somatic functions as indicated by head and wing phenotypes and decreased viability which result from amorphic cni mutations. The somatic, but not the ovarian functions of cni can be rescued by cornichon related (cnir). An earlier study in the lab revealed that a chromosomal deficiency removing regions including cnir is synthetically lethal with cni. A genetic screen was conducted to identify a putative loss of function allele of cnir, from an existing collection of EMS allele in this region. The molecular characterisation of the allele is not yet completed. In addition, an enhancer/suppressor screen in a sensitized genetic background to identify new components or new unidentified roles for known components, in the initiation of the DV axis was conducted. As the sensitized background, a cni hypomorphic allele combination which leads to strongly ventralized eggs with a weak defect in posterior follicle cell specification was used. Deficiencies on the third chromosome were assayed for suppression or enhancement of the cni egg phenotype or for synthetic lethality, upon gene dosage reduction.Eight candidates regions of the third chromosome consisting of one suppressor, four enhancers and three synthetic lethal were identified. The suppression was narrowed down to a single gene namely, pipe. pipe is a gene which is activated directly by the Grk gradient and its activity defines the ventral side of the egg and embryo. Of the other interactors, four of them have been narrowed down to regions containing a few genes

Interdisciplinary studies on stingless bees as alternate managed pollinators

The aim of the work described in this thesis is to improve the preparedness of the horticulture industry for the possible incursion of varroa mite and decline of managed honey bees by developing stingless bees as alternate managed pollinators. In this thesis, we conduct various surveys and experiments that contribute to improving pollination provisioning by native stingless bees. With research predicting ongoing changes in the global environment and resultant fluctuations in pollinator communities , it has become essential to focus on studying alternate and native pollinators. One such pollinator group is the stingless bees, which have a pan-tropical distribution, with a few species in the subtropics and temperate regions. The chapters of my thesis address questions that are yet to be solved regarding adoption of alternate managed pollination, such as the influence of farm management on crop pollination, and documenting the current knowledge among growers and beekeepers regarding managed pollination in India and Australia. In Chapter 2 I study and establish the current nature and status of beekeeping practices in India. Additionally, I study the current knowledge of growers regarding pollinators and pollination service. Overall it was established that growers know very little about pollination and beekeepers predominantly keep the honeybee, Apis mellifera, for honey production rather than for pollination. I then survey the Australian stingless bee industry (Chapter 3), documenting its growth in the past decade and comparing observed patterns to those in two previous decadal surveys. The decadal survey concludes that the stingless bee industry has a higher growth rate than the honey bee industry in Australia. An important step in developing stingless bees as alternate managed pollinators is to look at the effect of farm management on various insect visitors such as pollinators, beneficials and pests. In Chapter 4 I study the effects of farm management practices on insect visitors to conclude that low-spray management practices are an effective method to combat pests while maintaining unmanaged pollinators and beneficials on the orchard. Lastly, I compare various pollination methods – stingless bee pollination, hand pollination and no pollination within a protected cropping system for strawberry production and compare their cost-effectiveness (Chapter 5). The study concludes that strawberry growers will benefit from investing in bee pollination to improve their economic efficiency. Ultimately, these new insights contribute towards our understanding in developing stingless bees as alternated managed pollinators

Blended Learning: The Student Viewpoint

Background: Blended learning (BL) is defined as “a way of meeting the challenges of tailoring learning and development to the needs of individuals by integrating the innovative and technological advances offered by online learning with the interaction and participation offered in the best of traditional learning.” The Gulf Medical University (GMU), Ajman, UAE, offers a number of courses which incorporate BL with contact classes and online component on an E‑learning platform. Insufficient learning satisfaction has been stated as an obstacle to its implementation and efficacy.Aim: To determine the students’ perceptions toward BL which in turn will determine their satisfaction and the efficacy of the courses offered.Subjects and Methods: This was a cross‑sectional study conducted at the GMU, Ajman between January and December 2013. Perceptions of BL process, content, and ease of use were collected from 75 students enrolled in the certificate courses offered by the university using a questionnaire. Student perceptions were assessed using Mann–Whitney U‑test and Kruskal–Wallis test on the basis of gender, age, and course enrollment.Results: The median scores of all the questions in the three domains were above three suggesting positive perceptions on BL. The distribution of perceptions was similar between gender and age. However, significant differences were observed in the course enrollment (P = 0.02).Conclusion: Students hold a positive perception of the BL courses being offered in this university. The difference in perceptions among students of different courses suggest that the BL format offered needs modification according to course content to improve its perception.Keywords: Blended learning, Online learning, Students’ perception

On Brooks' Theorem

In this note we give two proofs of Brooks' Theorem. The first is obtained by modifying an earlier proof and the second by combining two earlier proofs. We believe these proofs are easier to teach in Computer Science courses.Comment: 5 page

Single-Crystalline Graphene by Low-Pressure CVD Method: Nucleation Limited Growth, Transfer, and Characterization

Graphene has attracted enormous attention due to its unique characteristics. However, the LPCVD graphene grown on copper turns out to be polycrystalline because of the high nucleation density (ND) on the copper foil surface. In order to realize better quality LPCVD graphene, this ND needs to be significantly reduced. Based on the observations from our initial graphene growths on as-received copper, we figured that the uneven Cu surfaces with defects produce large NDs. At a large ND, the graphene flakes nucleated at different sites coalesced to produce polycrystalline graphene. Due to such issues, we have implemented an electropolishing technique to smoothen the native surface of the copper foil. We will discuss the successful implementation of the surface smoothening process to reduce nucleation site formation while limiting the surface defects (which leads to wrinkle formation). The annealing process was also helpful to flatten the surface during the growth process further. We have also observed that graphene grows across Cu grain boundaries and, in the process, produces an additional surface area for graphene growth. That later causes to form wrinkles, which affect graphene properties negatively. In the next project, the effect of multi-step copper surface oxidization, base pressure vacuum in the middle of the process, and integration of Cu enclosures on suppressing the ND will be discussed. The technique is based on the self-cleaning characteristics of copper oxides and the metal evaporation in a high vacuum at high temperatures. The ND has reduced to ~5 nucleation/cm2 on average (an improvement compared to the previously reported minimum value, ten nucleation/cm2 which was obtained using copper enclosures), and the graphene/copper surface has become smoother. The self-aligned graphene island geometry and shape of the flakes have reflected the symmetry and the single crystallinity of graphene. The final project will discuss the growth of cm-scale graphene flakes on Cu and 3D-multilayered graphene on 3D-Ni foams and used Ni\u27s gettering carbon diffusion effect to make the Cu foil carbon-free. The Ni-foam/Cu enclosure was oxidized in situ to assist with the self-cleaning process of metal oxides. The ND has been reduced to ~0.57 nucleation/cm2 and obtained cm-scale graphene flakes

An Unusual case of flaccid Quadriplegia

This case describes a 47 years old Obese post menopausal lady with sudden onset flaccid quadriparesis with sparing of posterior column sensation .She has a prior history of Diabetes mellitus ,systemic hypertension ,Dyslipidemia , and hypothyroidism on regular .She was admitted for 1 day history of fever and malaise, laboratory parameters suggestive of a Possible a viral ethnology .She developed sudden onset of weakness, initially started on her Lower limb and progressing to her upper limb within few hours along with bladder involvement which appeared on the next day of hospitalisation prompt thinking of a demyelination like pattern after ruling out mechanical causes with a radiograph .In the background of a fever prompted thinking of a fast progressing demyelination like a GBS/ADEM and even started IVIG as there is always some time delay for MRI to arrive. The MRI report suggested of Thrombosis of ASA territory involving the anterior paramedian aspect of Medulla extending up to the upper cervical cord. She remained quadriplegic thereafter and 6 months later despite receiving antiplatelets, Physiotherapy and other supportive treatments. The case described here elaborates the clinical presentation and outcome of ASA thrombosis. ASA thrombosis though rare is be thought as a differential of acute onset flaccid quadriparesis in an acute setting .The clinical course and devastating nature of illness should be aware off. Its necessary to diagnose this syndrome in the earliest when patient presents with acute onset of motor weakness sparing the posterior column sensatio