Sequence correlations shape protein promiscuity

We predict analytically that diagonal correlations of amino acid positions within protein sequences statistically enhance protein propensity for nonspecific binding. We use the term 'promiscuity' to describe such nonspecific binding. Diagonal correlations represent statistically significant repeats of sequence patterns where amino acids of the same type are clustered together. The predicted effect is qualitatively robust with respect to the form of the microscopic interaction potentials and the average amino acid composition. Our analytical results provide an explanation for the enhanced diagonal correlations observed in hubs of eukaryotic organismal proteomes [J. Mol. Biol. 409, 439 (2011)]. We suggest experiments that will allow direct testing of the predicted effect

On Topological Susceptibility, Vacuum Energy and Theta Dependence in Gluodynamics

We suggest that the topological susceptibility in gluodynamics can be found in terms of the gluon condensate using renormalizability and heavy fermion representation of the anomaly. Analogous relations can be also obtained for other zero momentum correlation functions involving the topological density operator. Using these relations, we find the theta dependence of the condensates , and of the partition function for small theta and an arbitrary number of colors.Comment: Details of the derivation are clarified, changes in discussions, new references are adde

The Gauge Fields and Ghosts in Rindler Space

We consider 2d Maxwell system defined on the Rindler space with metric ds^2=\exp(2a\xi)\cdot(d\eta^2-d\xi^2) with the goal to study the dynamics of the ghosts. We find an extra contribution to the vacuum energy in comparison with Minkowski space time with metric ds^2= dt^2-dx^2. This extra contribution can be traced to the unphysical degrees of freedom (in Minkowski space). The technical reason for this effect to occur is the property of Bogolubov's coefficients which mix the positive and negative frequencies modes. The corresponding mixture can not be avoided because the projections to positive -frequency modes with respect to Minkowski time t and positive -frequency modes with respect to the Rindler observer's proper time \eta are not equivalent. The exact cancellation of unphysical degrees of freedom which is maintained in Minkowski space can not hold in the Rindler space. In BRST approach this effect manifests itself as the presence of BRST charge density in L and R parts. An inertial observer in Minkowski vacuum |0> observes a universe with no net BRST charge only as a result of cancellation between the two. However, the Rindler observers who do not ever have access to the entire space time would see a net BRST charge. In this respect the effect resembles the Unruh effect. The effect is infrared (IR) in nature, and sensitive to the horizon and/or boundaries. We interpret the extra energy as the formation of the "ghost condensate" when the ghost degrees of freedom can not propagate, but nevertheless do contribute to the vacuum energy. Exact computations in this simple 2d model support the claim made in [1] that the ghost contribution might be responsible for the observed dark energy in 4d FLRW universe.Comment: Final version to appear in Phys. Rev. D. Comments on relation with energy momentum computations and few new refs are adde

A GLI1-p53 inhibitory loop controls neural stem cell and tumour cell numbers

How cell numbers are determined is not understood. Hedgehog-Gli activity is involved in precursor cell proliferation and stem cell self-renewal, and its deregulation sustains the growth of many human tumours. However, it is not known whether GLI1, the final mediator of Hh signals, controls stem cell numbers, and how its activity is restricted to curtail tumourigenesis. Here we have altered the levels of GLI1 and p53, the major tumour suppressor, in multiple systems. We show that GLI1 expression in Nestin+ neural progenitors increases precursor and clonogenic stem cell numbers in vivo and in vitro. In contrast, p53 inhibits GLI1-driven neural stem cell self-renewal, tumour growth and proliferation. Mechanistically, p53 inhibits the activity, nuclear localisation and levels of GLI1 and in turn, GLI1 represses p53, establishing an inhibitory loop. We also find that p53 regulates the phosphorylation of a novel N' truncated putative activator isoform of GLI1 in human cells. The balance of GLI1 and p53 functions, thus, determines cell numbers, and prevalence of p53 restricts GLI1-driven stem cell expansion and tumourigenesis

Selective and Efficient Quantum Process Tomography

In this paper we describe in detail and generalize a method for quantum process tomography that was presented in [A. Bendersky, F. Pastawski, J. P. Paz, Physical Review Letters 100, 190403 (2008)]. The method enables the efficient estimation of any element of the $\chi$--matrix of a quantum process. Such elements are estimated as averages over experimental outcomes with a precision that is fixed by the number of repetitions of the experiment. Resources required to implement it scale polynomically with the number of qubits of the system. The estimation of all diagonal elements of the $\chi$--matrix can be efficiently done without any ancillary qubits. In turn, the estimation of all the off-diagonal elements requires an extra clean qubit. The key ideas of the method, that is based on efficient estimation by random sampling over a set of states forming a 2--design, are described in detail. Efficient methods for preparing and detecting such states are explicitly shown.Comment: 9 pages, 5 figure

Perancangan dan Pembuatan Sistem Informasi Kasir Berbasis Web pada Toko XYZ

Abstrak. Pandemi Covid-19 telah mengubah banyak aspek kehidupan kita, cara komunikasi, belajar  dan termasuk dalam melakukan transaksi. Hal ini memaksa banyak perusahaan beralih dari sistem pencatatan transaksi manual ke sistem pencatatan transaksi dengan menggunakan teknologi informasi (TI). Penggunaan TI dalam bertransaksi sebenarnya sudah ada sejak lama, namun pandemi ini mengakibatkan adanya peningkatan yang signifikan dalam penggunaan TI dalam berbisnis. Sistem transaksi yang terkomputerisasi, sistem yang dapat diakses secara online dan memiliki data dalam cloud semakin populer karena memungkinkan orang untuk melakukan pencatatan dan pengawasan dari jarak jauh tanpa harus melakukannya secara manual. Penggunan TI dalam proses bisnis akan sangat membantu dalam analisa data, karena data tersimpan dan terolah dengan baik sehingga dapat memberikan masukan atau pertimbangan untuk langkah bisnis berikutnya. Toko XYZ belum memiliki pencatatan yang sistematis, sehingga penjualan hanya dicatat seadanya saja dan tidak adanya fungsi laporan membuat pemilik kesulitan untuk melacak jumlah penjualan dan memutuskan langkah dalam bisnis. Penelitian ini menghasilkan sebuah aplikasi berbasis web yang membantu toko XYZ dalam melakukan pencatatan penjualan dan memberikan laporan penjualan untuk pemilik. Laporan penjualan dapat diberikan secara periodik sehingga membantu pemilik untuk dapat memutuskan langkah untuk melanjutakan proses bisnisnya.   Abstract. The Covid-19 pandemic has changed many aspects of our lives, the way we communicate, learn and make transactions. This has forced many companies to switch from manual transaction recording systems to transaction recording systems using information technology (IT). The use of IT in transactions has actually been around for a long time, but this pandemic has resulted in a significant increase in the use of IT in business. Computerized transaction systems, systems that can be accessed online and have data in the cloud are increasingly popular because they allow people to record and monitor remotely without having to do it manually. The use of IT in business processes will greatly assist in analyzing data, because the data is stored and processed properly so that it can provide input or consideration for the next business step. Store XYZ does not yet have systematic records, so sales only record them and the absence of a report function makes it difficult for the owner to track the number of sales and decide on steps in the business. This research produces a web-based application that helps XYZ stores record sales and provide sales reports to owners. Sales reports can be provided periodically so that it helps the owner to be able to decide on steps to continue his business process