“Beyond an acronym,STEM is…”: Perceptions of STEM

Although STEM is at the forefront of many educational initiatives, little is known about various professionals’ perceptions of STEM. This mixed‐methods study surveyed 164 preservice teachers, inservice teachers, administrators, informal educators, and STEM professionals. Quantitative and qualitative questions on the survey elicited participants’ perceptions of STEM, STEM support, and STEM careers. Quantitative analysis revealed that profession influenced understandings of STEM, importance of STEM, support for STEM, and perceptions of STEM career opportunities. Qualitative analysis provided rich explanations for the differences in perceptions among professions. This study suggests that science teacher educators need to ensure preservice teachers have understandings of STEM and STEM careers, K‐16 educators need to emphasize the current importance of STEM, and administrators and policymakers need to align visions of STEM with curriculum and pacing guides so teachers feel supported in their STEM endeavors.     

Multi-stage stochastic programming models for provisioning cloud computing resources

We focus on the resource provisioning problem of a cloud consumer from an Infrastructure-as-a-Service type of cloud. The cloud provider offers two deployment options, which can be mixed and matched as appropriate. Cloud instances may be reserved for a fixed time period in advance at a smaller usage cost per hour but require a full commitment and payment for the entire contract duration. In contrast, on-demand instances reflect a pay-as-you-go policy at a premium. The trade-off between these two options is rooted in the inherent uncertainty in demand and price and makes it attractive to complement a base reserved capacity with on-demand capacity to hedge against the spikes in demand. This paper provides several novel multi-stage stochastic programming formulations to enable a cloud consumer to handle the cloud resource provisioning problem at a tactical level. We first formulate the cloud resource provisioning problem as a risk-neutral multi-stage stochastic program, which serves as the base model for further modeling variants. In our second set of models, we also incorporate a certain concept of system reliability. In particular, chance constraints integrated into the base formulation require a minimum service level met from reserved capacity, provide more visibility into the future available capacity, and smooth out expensive on-demand usage by hedging against possible demand fluctuations. An extensive computational study demonstrates the value of the proposed models by discussing computational performance, gleaning practical managerial insights from the analysis of the solutions of the proposed models, and quantifying the value of the stochastic solutions.     

QCD phase transition with strange quark in wilson formalism for fermions

The nature of QCD phase transition is studied with massless up and down quarks and a light strange quark, using the Wilson formalism for quarks on a lattice with the temporal direction extensionN _t=4. We find that the phase transition is of first order for the physical strange quark mass.     

Preparation of CTA-based polymer inclusion membrane using calix[4]arene derivative as a carrier for Cr(VI) transport

In this work, the transport of Cr(VI) ions from an aqueous donor phase solution to an acceptor phase that contained an acetic acid/ammonium acetate buffer at pH 5 through a polymer inclusion membrane (PIM) containing p-tert-butylcalix[4]arene amine derivative as carrier was studied. The Cr(VI) passed through a PIM comprised of cellulose triacetate as a support and 2-NPOE as a plasticizer. The transport efficiency of Cr(VI) was studied under various experimental conditions, such as effect of carrier concentration, acceptor phase pH, type of plasticizer in the membrane, stirring rate and membrane thickness. The kinetic parameters were calculated as rate constant (k), permeability coefficient (P), and flux (J). The transport efficiency of Cr(VI) was observed to be 95.07 % after 10 h under optimized conditions. The prepared PIM was characterized with Fourier transform infrared spectroscopy and the atomic force microscopy techniques as well as with contact angle measurements. This is an effective method for the removal of Cr(VI) which is toxic for human body and environment from the waste water.     

Reply to Comments on “Non-Darcian Forced Convection Flow of Viscous Dissipating Fluid over a Flat Plate Embedded in a Porous Medium”

In this note, we reply to the comments by Rees and Magyari (2007) on our article (Aydin and Kaya 2007). They mainly stated that the thermal boundary conditions we defined at the edge of the boundary layer were incompatible with the energy equation. This is questionable and therefore we will discuss it below. They disclosed that our results were in error. However, this is quite misleading. Scientifically, they cannot reach such a conclusion without comparing our results with what they thought to be correct. In fact, this misleading and unproven statement will be shown not to be correct in the following.     

A novel chip device based on wired capillary packed with high performance polymer-based monolith for HPLC: reproducibility in preparation processes to obtain long columns.

This report describes the development of novel wired chip devices for mu-HPLC analyses. The monolithic capillary column to be wired was prepared using a tri-functional epoxy monomer, tris(2,3-epoxypropyl)isocyanurate with a diamine, 4-[(4-aminocyclohexyl)methyl]cyclohexylamine. The prepared column was evaluated by SEM observation of the sectional structure of column and micro-HPLC. In addition, the reproducibility in the preparation of long capillary columns having nearly 1 m length was extensively examined for applications of novel wired chip devices. The authors demonstrated that the monolithic structure of the prepared long capillary could be finely controlled under the strictly maintained operational conditions and thus the relative standard deviation (RSD) of the column properties such as the number of theoretical plates, retention factor, and permeability could be well controlled to become less than 10%. Furthermore, the wired chip device column showed that its high performance was kept even after chip preparation.     

SYNTHESIS, CHARACTERIZATION AND THERMAL DEGRADATION KINETICS OF POLY(IMINO ISOPHTHALOYL IMINO (2,4,8,10-TETRAOKSOASPIRO [5,5] UNDEKAN-3,9-DIPROPYLENE))

A new polymer,poly(imino isophthaloyl imino(2,4,8,10-tetraoksoaspiro[5,5]undekan-3,9-dipropylene)) [poly(IPIT)]was synthesized by an interfacial polycondensation reaction.The characterization of poly(IPIT)was conducted by using FT-IR,~(13)C-NMR,TG and DTA techniques.The kinetics of the thermal degradation of poly(IPIT)was investigated by thermogravimetric analysis at different heating rates.TG curves showed that the thermal decomposition of poly(IPIT) occurred in three stages.The apparent activation ener...     

Synthesis, spectral, thermal and biological studies of Co(III) and binuclear Ni(II) complexes with a novel amine-imine-oxime ligand

Two different metal complexes of [Co(HL)(L)(Ac)₂]·4H₂O (I) and [Ni₂(L)₂(Ac)₂]·4H₂O (II), have been synthesized with newly prepared amine-imine-oxime ligand [HL = 3-(4′-aminobiphenyl-4-ylimino)-butan-2-one oxime, Ac = CH₃COO⁻]. This ligand HL was prepared by the condensation of diacetylmonoxime with benzidine. The structure of the ligand and complexes have been proposed by elemental analyses, IR, ¹H, and ¹³C NMR, electronic spectra, magnetic susceptibility measurements, mass spectra, molar conductivity and thermo gravimetric analysis. The molar conductance measurements of the complexes in DMF solution correspond to non electrolytic nature for the complexes. Octahedral and tetrahedral geometries have been determined to the complexes of Co(III) and binuclear Ni(II) respectively. The ligand and its metal complexes were tested in vitro for their biological effects. Their activities against two gram-positive (Bacillus subtilis and Staphylococcus aureus) and one fungal specie (Candida albicans) were found. They were inactive against tested gram negative bacteria. The text was submitted by authors in English.