Surface states on a topologically non-trivial semimetal: The case of Sb(110)

The electronic structure of Sb(110) is studied by angle-resolved photoemission spectroscopy and first-principle calculations, revealing several electronic surface states in the projected bulk band gaps around the Fermi energy. The dispersion of the states can be interpreted in terms of a strong spin-orbit splitting. The bulk band structure of Sb has the characteristics of a strong topological insulator with a Z2 invariant nu0=1. This puts constraints on the existence of metallic surface states and the expected topology of the surface Fermi contour. However, bulk Sb is a semimetal, not an insulator and these constraints are therefore partly relaxed. This relation of bulk topology and expected surface state dispersion for semimetals is discussed.Comment: 7 pages, 4 figure

EGF-stimulation activates the nuclear localization signal of SHP-1

Protein tyrosine phosphatase SHP-1 plays a critical role in the regulation of a variety of intracellular signaling pathways. SHP-1 is predominantly expressed in the cells of hematopoietic origin, and is recognized as a negative regulator of lymphocyte development and activation. SHP-1 consists of two Src homology 2 (SH2) domains and one protein tyrosine phosphatase (PTP) domain followed by a highly basic C-terminal tail containing tyrosyl phosphorylation sites. It is unclear how the C-terminal tail regulates SHP-1 function. We report the examination of the subcellular localization of a variety of truncated or mutated SHP-1 proteins fused with enhanced green fluorescent protein (EGFP) protein at either the N-terminal or the C-terminal end in different cell lines. Our data demonstrate that a nuclear localization signal (NLS) is located in the C-terminal tail of SHP-1 and the signal is primarily defined by three amino-acid residues (KRK) at the C-terminus. This signal is generally blocked in the native protein and can be exposed by fusing EGFP at the appropriate position or by domain truncation. We have also revealed that this NLS of SHP-1 is triggered by epidermal growth factor (EGF) stimulation and mediates translocation of SHP-1 from the cytosol to the nucleus in COS7 cell lines. These results not only demonstrate the importance of the C-terminal tail of SHP-1 in the regulation of nuclear localization, but also provide insights into its role in SHP-1-involved signal transduction pathways. © 2004 Wiley-Liss, Inc

A Replica Inference Approach to Unsupervised Multi-Scale Image Segmentation

We apply a replica inference based Potts model method to unsupervised image segmentation on multiple scales. This approach was inspired by the statistical mechanics problem of "community detection" and its phase diagram. Specifically, the problem is cast as identifying tightly bound clusters ("communities" or "solutes") against a background or "solvent". Within our multiresolution approach, we compute information theory based correlations among multiple solutions ("replicas") of the same graph over a range of resolutions. Significant multiresolution structures are identified by replica correlations as manifest in information theory overlaps. With the aid of these correlations as well as thermodynamic measures, the phase diagram of the corresponding Potts model is analyzed both at zero and finite temperatures. Optimal parameters corresponding to a sensible unsupervised segmentation correspond to the "easy phase" of the Potts model. Our algorithm is fast and shown to be at least as accurate as the best algorithms to date and to be especially suited to the detection of camouflaged images.Comment: 26 pages, 22 figure

Inference of hidden structures in complex physical systems by multi-scale clustering

We survey the application of a relatively new branch of statistical physics--"community detection"-- to data mining. In particular, we focus on the diagnosis of materials and automated image segmentation. Community detection describes the quest of partitioning a complex system involving many elements into optimally decoupled subsets or communities of such elements. We review a multiresolution variant which is used to ascertain structures at different spatial and temporal scales. Significant patterns are obtained by examining the correlations between different independent solvers. Similar to other combinatorial optimization problems in the NP complexity class, community detection exhibits several phases. Typically, illuminating orders are revealed by choosing parameters that lead to extremal information theory correlations.Comment: 25 pages, 16 Figures; a review of earlier work

Niche specialization of reef-building corals in the mesophotic zone: metabolic trade-offs between divergent Symbiodinium types

The photobiology of two reef corals and the distribution of associated symbiont types were investigated over a depth gradient of 0–60 m at Scott Reef, Western Australia. Pachyseris speciosa hosted mainly the same Symbiodinium C type similar to C3 irrespective of sampling depth. By contrast, Seriatopora hystrix hosted predominantly Symbiodinium type D1a or D1a-like at shallow depths while those in deeper water were dominated by a Symbiodinium C type closely related to C1. The photosynthesis/respiration (P/R) ratio increased consistently with depth at the two sampling times (November 2008 and April 2009) for P. speciosa and in November 2008 only for S. hystrix, suggesting a reduction in metabolic energy expended for every unit of energy obtained from photosynthesis. However, in April 2009, shallow colonies of S. hystrix exhibited decreased P/R ratios down to depths of approximately 23 m, below which the ratio increased towards the maximum depth sampled. This pattern was mirrored by changes in tissue biomass determined as total protein content. The depth of change in the direction of the P/R ratio correlated with a shift from Symbiodinium D to C-dominated colonies. We conclude that while photobiological flexibility is vital for persistence in contrasting light regimes, a shift in Symbiodinium type may also confer a functional advantage albeit at a metabolic cost with increased depth

Stimulation of Na⁺/H⁺ Exchanger Isoform 1 Promotes Microglial Migration

Regulation of microglial migration is not well understood. In this study, we proposed that Na+/H+ exchanger isoform 1 (NHE-1) is important in microglial migration. NHE-1 protein was co-localized with cytoskeletal protein ezrin in lamellipodia of microglia and maintained its more alkaline intracellular pH (pHi). Chemoattractant bradykinin (BK) stimulated microglial migration by increasing lamellipodial area and protrusion rate, but reducing lamellipodial persistence time. Interestingly, blocking NHE-1 activity with its potent inhibitor HOE 642 not only acidified microglia, abolished the BK-triggered dynamic changes of lamellipodia, but also reduced microglial motility and microchemotaxis in response to BK. In addition, NHE-1 activation resulted in intracellular Na+ loading as well as intracellular Ca2+ elevation mediated by stimulating reverse mode operation of Na+/Ca2+ exchange (NCXrev). Taken together, our study shows that NHE-1 protein is abundantly expressed in microglial lamellipodia and maintains alkaline pHi in response to BK stimulation. In addition, NHE-1 and NCXrev play a concerted role in BK-induced microglial migration via Na+ and Ca2+ signaling. © 2013 Shi et al

LINGKUNGAN BISNIS PETERNAK SAPI PERAH TERHADAP POSITIONING KOPERASI SERTA IMPLIKASINYA PADA KINERJA PEMASARAN (Studi Pada Pelaku Usaha Bisnis Sapi Perah di Provinsi Jawa Barat)

Latar Belakang : Dalam perspektif bisnis, peternak sapi perah memiliki peluang yang tinggi, mengingat susu sapi sebagai kebutuhan setiap manusia untuk memenuhi kebutuhan nutrisi tubuh, tetapi total kebutuhan nasional untuk produksi susu tahun 2018 sekitar 4,5 juta ton per tahun hanya dipenuhi dari produksi lokal hanya sebesar 18% (920 ton) atau sekitar 82% kebutuhan susu dipenuhi dengan impor. Di sisi lain menunjukan bahwa jumlah populasi sapi perah di Indonesia terus turun. Sampai 2016, jumlah populasi sapi tercatat 291.183 ekor, jauh berkurang dibandingkan 2013 sebanyak 438.745 ekor atau berkurang sebanyak 33%. Angka ini juga sejalan dengan penurunan jumlah peternak di Indonesia. Pada 2016, jumlah peternak yang tergabung dalam koperasi mencapai 96.355 orang, turun dibandingkan 2013 sebanyak 102.726 orang, atau berkurang sekitar 7%. Permasalahan pokok dalam penelitian ini ialah kinerja pemasaran pada peternak sapi perah di provinsi Jawa Barat, hal ini didasarkan oleh lingkungan bisnis terhadap positioning koperasi dalam memenuhi layanan kepada anggota koperasi Tujuan : Hasil penelitian secara deskriftif lingkungan bisnis dan positioning koperasi memberikan kontribusi terhadap kinerja pemasaran peternak sapi perah di provinsi Jawa Barat. Walaupun dalam pelaksanaannya secara umum belum sepenuhnya didasarkan atas aspek-aspek lingkungan bisnis dan posisi koperasi sebagai wadah bahgi para peternak sapi perah. Metode : Metode penelitian ini adalah metode survey sebagai upaya mengumpulkan informasi dari responden dengan menggunakan angket, hal ini dimaksudkan untuk menguji jawaban rasional sehingga dapat menjelaskan fenomena yang menjadi masalah, dengan model analisis SEM (Structural Equation Modelling). Hasil Penelitian : Hasil penelitian secara simultan menunjukan bahwa lingkungan bisnis eksternal dan internal besar pengaruhnya terhadap positioning koperasi sebesar 40,4% sedangkan epsilonnya 18,7 %. Sementara pengaruh lingkungan bisniseksternal terhadap positioning koperas sebesar 82% sementara pengaruh lingkungan bisnis internal terhadap positioning koperasi sebesar 17%. Hal ini menunjukan bahwa lingkungan peternak sapi perah di provinis Jawa Barat memiliki ketergantungan yang sangat kuat terhdap lingkungan bisnis eksternal, dibanding terhdap lingkungan bisnis internal. Adapun postioning koperasi memberikan pengearuh terhadap kinerja pemasaran sebesar 93% dengan epsilon 13,5%. Dengan demikian lingkungan bisnis dan positioning koperasi dapat dijadikan indikator yang diharapkan dapat untuk memperbaiki kinerja pemasaran peternak sapi perah di provinsi Jawa Barat. Kata Kunci : Lingkungan Bisnis Eksternal, Lingkungan Bisnis Internal, Positioning Koperasi dan Kinerja Pemasara

Searching for C ii Emission from the First Sample of z ∼ 6 O i Absorption-associated Galaxies with the Atacama Large Millimeter/submillimeter Array

We report the first statistical analyses of [C ii ] and dust continuum observations in six strong O i absorber fields at the end of the reionization epoch obtained by the Atacama Large Millimeter/submillimeter Array (ALMA). Combined with one [C ii ] emitter reported in Wu et al., we detect one O i -associated [C ii ] emitter in six fields. At redshifts of O i absorbers in nondetection fields, no emitters are brighter than our detection limit within impact parameters of 50 kpc and velocity offsets between ±200 km s ^−1 . The averaged [C ii ]-detection upper limit is 50 kpc) and having larger outflow velocities within ±600 km s ^−1 . If these detections are confirmed in the future, then the mechanism of pushing metals at larger distances with higher velocities needs to be further explored from the theoretical side