Ground State Properties of an Asymmetric Hubbard Model for Unbalanced Ultracold Fermionic Quantum Gases

In order to describe unbalanced ultracold fermionic quantum gases on optical lattices in a harmonic trap, we investigate an attractive ($U<0$) asymmetric ($t_\uparrow\neq t_\downarrow$) Hubbard model with a Zeeman-like magnetic field. In view of the model's spatial inhomogeneity, we focus in this paper on the solution at Hartree-Fock level. The Hartree-Fock Hamiltonian is diagonalized with particular emphasis on superfluid phases. For the special case of spin-independent hopping we analytically determine the number of solutions of the resulting self-consistency equations and the nature of the possible ground states at weak coupling. Numerical results for unbalanced Fermi-mixtures are presented within the local density approximation. In particular, we find a fascinating shell structure, involving normal and superfluid phases. For the general case of spin-dependent hopping we calculate the density of states and the possible superfluid phases in the ground state. In particular, we find a new magnetized superfluid phase.Comment: 9 pages, 5 figure

Transport of a quantum degenerate heteronuclear Bose-Fermi mixture in a harmonic trap

We report on the transport of mixed quantum degenerate gases of bosonic 87Rb and fermionic 40K in a harmonic potential provided by a modified QUIC trap. The samples are transported over a distance of 6 mm to the geometric center of the anti-Helmholtz coils of the QUIC trap. This transport mechanism was implemented by a small modification of the QUIC trap and is free of losses and heating. It allows all experiments using QUIC traps to use the highly homogeneous magnetic fields that can be created in the center of a QUIC trap and improves the optical access to the atoms, e.g., for experiments with optical lattices. This mechanism may be cascaded to cover even larger distances for applications with quantum degenerate samples.Comment: 7 pages, 8 figure

DNA Renaturation at the Water-Phenol Interface

We study DNA adsorption and renaturation in a water-phenol two-phase system, with or without shaking. In very dilute solutions, single-stranded DNA is adsorbed at the interface in a salt-dependent manner. At high salt concentrations the adsorption is irreversible. The adsorption of the single-stranded DNA is specific to phenol and relies on stacking and hydrogen bonding. We establish the interfacial nature of a DNA renaturation at a high salt concentration. In the absence of shaking, this reaction involves an efficient surface diffusion of the single-stranded DNA chains. In the presence of a vigorous shaking, the bimolecular rate of the reaction exceeds the Smoluchowski limit for a three-dimensional diffusion-controlled reaction. DNA renaturation in these conditions is known as the Phenol Emulsion Reassociation Technique or PERT. Our results establish the interfacial nature of PERT. A comparison of this interfacial reaction with other approaches shows that PERT is the most efficient technique and reveals similarities between PERT and the renaturation performed by single-stranded nucleic acid binding proteins. Our results lead to a better understanding of the partitioning of nucleic acids in two-phase systems, and should help design improved extraction procedures for damaged nucleic acids. We present arguments in favor of a role of phenol and water-phenol interface in prebiotic chemistry. The most efficient renaturation reactions (in the presence of condensing agents or with PERT) occur in heterogeneous systems. This reveals the limitations of homogeneous approaches to the biochemistry of nucleic acids. We propose a heterogeneous approach to overcome the limitations of the homogeneous viewpoint

Investigation of a Protein Complex Network

The budding yeast {\it Saccharomyces cerevisiae} is the first eukaryote whose genome has been completely sequenced. It is also the first eukaryotic cell whose proteome (the set of all proteins) and interactome (the network of all mutual interactions between proteins) has been analyzed. In this paper we study the structure of the yeast protein complex network in which weighted edges between complexes represent the number of shared proteins. It is found that the network of protein complexes is a small world network with scale free behavior for many of its distributions. However we find that there are no strong correlations between the weights and degrees of neighboring complexes. To reveal non-random features of the network we also compare it with a null model in which the complexes randomly select their proteins. Finally we propose a simple evolutionary model based on duplication and divergence of proteins.Comment: 19 pages, 9 figures, 1 table, to appear in Euro. Phys. J.

Reclaiming Lost Moments

Linfield’s Second Chance Prom was a dance and so much mor

Building safe and supportive communities

Holistic and student-led approaches increase safety on Linfield’s campuse

Recipient of the 2023 Alumni Titan Award

Dr. Angel Alvarez ‘98 Dr. Angel Alvarez is the Director of the Stem Cell Core and a Research Assistant Professor in the Department of Neurology at Northwestern University. He has extensive experience in stem cell biology, imaging, gene delivery, and biotechnology. As the Director of the Northwestern Stem Cell Core, he establishes disease models to accelerate therapeutic development using organoid technology and patient-derived induced pluripotent stem cells. Many of the most rewarding aspects of his current position are derived from the Core’s exciting collaborations in reproductive biology, neuroscience, and pathology. Beyond his lab research, Dr. Alvarez has a passion for employing his analytical skills to address inequity in education. During his doctoral research, Dr. Alvarez investigated the development of stem cell technologies and the biology of cancer. He demonstrated the critical role of nanog in facilitating induced pluripotency and established patient-derived cell lines to characterize gene expression, cell pathway activation, and protein markers in brain tumors. During his post-doctoral research, he developed tumor stem cell lines to study oncogenic signaling and factors that mediate tumor growth, invasion, and radiation resistance, notably through Wnt signaling and exosome secretion. Dr. Alvarez has earned several competitive awards, including separate pre- and post-doctoral T32 fellowships, in addition to funding from universities, private foundations, and the NIH. His research has led to the development of exciting intellectual property in both stem cell technology and cancer, yielding 11 issued US patents as well as multiple pending and international patents. He has served as a mentor to numerous emerging scholars, including several IMSA SIR students, and is most proud of being a father to his amazing daughter

Changed by the pandemic

A resurgent interest in public health and a sharper focus on the mental health of those delivering care are among the lasting transformations resulting from a worldwide crisis

Reducing Barriers

The Linfield community is fighting the underrepresentation of women in STEM in K-12, college and beyon

Odontogenic Cysts of upper jaw an analysis

This article attempts to analyze all cases of odontogenic cysts involving upper jaw who presented at Stanley Medical college during 2007 – 2012. This article analyzes the incidence of these cystsduring the above said period, age of occurence, sex prediliction if any, clinical presentations and optimal treatment modality. Common complaints with which patients presented to our Institutionwas swelling over jaw, next was loosening of dentition, paresthesia. 30 patients had presented with cysts involving upper jaw out of which 29 were females and one was male. All these patientsunderwent surgical removal of the cystic lesion.