324,233 research outputs found
Sums of Products of Polynomials in Few Variables: Lower Bounds and Polynomial Identity Testing
No full textWe study the complexity of representing polynomials as a sum of products of polynomials in few variables. More precisely, we study representations of the form P = sum_{i=1}^T prod_{j=1}^d Q_{ij} such that each Q_{ij} is an arbitrary polynomial that depends on at most s variables.
We prove the following results.
1. Over fields of characteristic zero, for every constant mu such that 0= n^{Omega(sqrt(n))}. This strengthens a recent result of Kayal and Saha [Kayal/Saha, ECCC 2014] which showed similar lower bounds for the model of sums of products of linear forms in few variables. It is known that any asymptotic improvement in the exponent of the lower bounds (even for s=sqrt(n)) would separate VP and VNP [Kayal/Saha, ECCC 2014].
2. We obtain a deterministic subexponential time blackbox polynomial identity testing (PIT) algorithm for circuits computed by the above model when T and the individual degree of each variable in P are at most log^{O(1)}(N) and s<=N^{mu} for any constant mu<1/2. We get quasipolynomial running time when s<log^{O(1)}(N). The PIT algorithm is obtained by combining our lower bounds with the hardness-randomness tradeoffs developed in [Dvir/Shpilka/Yehudayoff, SIAM J. Comp. 2009; Kabanets/Impagliazzo, Comp. Compl. 2004]. To the best of our knowledge, this is the first nontrivial PIT algorithm for this model (even for the case s=2), and the first nontrivial PIT algorithm obtained from lower bounds for small depth circuits
Papil Saraf Otak
No full textracii saraf optik meruoa~c ~n bagia~ terpendek
kes e luruh~n sar~f optik yang dalam perkembangannya mempunyai
hubunqan dengan otak bagian depan melalui tang kai optik .
Papil saraf optik adalah bagian intra okuler dc-.r i
optik yang memiiiki struktur tida ~ jauh berbeda dengan sara¥
optik. dimana sa at memasuki bo12m~~a tidak lagi diselubunqi
olen selaout mieiin . dan mendap~~ suclai dar-ah sebagian
besar melalui sirkulasi arteri 5i11aris posterior brevi s.
Gambaran papil sara; ootik S2cara o~talmoskooi disebut
disk~s opti kus, Dada umumnya bero2ntuk 10njong dengan arah
vertika! dimana bag ian sentral darl diskus terdaoat suatu
gaung yang berwarna sedikit leblh c~ca~
PEMODELAN ALIRAN LISTRIK PADA SEL SARAF MANUSIA
No full textSeluruh aktifitas yang yang terjadi pada tubuh manusia dikendalikan oleh sistem saraf pusat. Sistem saraf pusat merupakan sistem koordinasi tubuh yang terdiri dari berjuta-juta sel saraf (neuron). Sel saraf (neuron) adalah unit satuan struktural terkecil pada sistem saraf yang bekerja untuk menghantarkan muatan berupa ion-ion dari dendrit menuju akson. Oleh karena itu, tujuan dari penelitian ini adalah untuk menganalisis aliran listrik pada sel saraf manusia menggunakan model RLC seri sirkuit. Analisis aliran listrik pada sel saraf manusia dilakukan pada dua kawasan yaitu kawasan frekuensi dan kawasan waktu. Analisis pada kawasan frekuensi bertujuan untuk mengetahui besar tanggapan yang baik pada sel saraf manusia. Analisis pada kawasan waktu bertujuan untuk mendeteksi besar muatan yang dihantarkan pada waktu detik dan untuk mendeteksi hambatan optimum pada sel saraf manusia. Hasil analisis pada kawasan frekuensi diperoleh tanggapan keluaran pada sel saraf manusia (vout(s)) dengan faktor peredam α, frekuensi resonansi ω0 radian/detik dan faktor kualitas Q yang ditentukan dari tanggapan keluaran. Hasil pada kawasan waktu diperoleh besar muatan pada waktu t detik dan besar hambatan optimum pada sel saraf manusia.Kata Kunci : Arus listrik, Membran plasma, Rangkaian sel sara
Overexpression of SARAF Ameliorates Pressure Overload–Induced Cardiac Hypertrophy Through Suppressing STIM1-Orai1 in Mice
No full textBackground/Aims: Activation of stromal interaction molecule 1 (STIM1) and Orai1 participates in the development of cardiac hypertrophy. Store-operated Ca2+ entry-associated regulatory factor (SARAF) is an intrinsic inhibitor of STIM1-Orai1 interaction. Thus, we hypothesized that SARAF could prevent cardiac hypertrophy. Methods: Male C57BL/6 mice, aged 8 weeks, were randomly divided into sham and abdominal aortic constriction surgery groups and were infected with lentiviruses expressing SARAF and GFP (Lenti-SARAF) or GFP alone (Lenti-GFP) via intramyocardial injection. At 4 weeks after aortic constriction, left ventricular structure and function were assessed by echocardiography and hemodynamic assays. The gene and protein expressions of SARAF, STIM1, and Orai1 were measured by quantitative PCR and Western blot, respectively. Results: Gene and protein expressions of SARAF were significantly decreased, while STIM1 and Orai1 were increased in the heart tissue compared with sham group. Overexpression of SARAF in the heart prevented the upregulation of STIM1 and Orai1, and importantly, attenuated aortic constriction-induced decrease in maximal rate of left ventricular pressure decay and increases in thickness of interventricular septum and left ventricular posterior wall, heart weight/body weight ratio, and size of cardiomyocytes. Blood pressure detected through the carotid artery and left ventricular systolic function were not affected by SARAF overexpression. In addition, overexpression of SARAF also attenuated angiotensin II-induced upregulation of STIM1 and Orai1 and hypertrophy of cultured cardiomyocytes. Conclusion: Overexpression of SARAF in the heart prevents cardiac hypertrophy, probably through suppressing the upregulation of STIM1/Orai1.</jats:p
Memperkenalkan: Sistem Saraf Saluran Pencernaan Sebagai Otak Kedua
No full textPada abad ke-19, Bayliss dan Sterling menemukan gerakan peristalsis yang mendorong makanan d dalam usus ke arah distal walaupun persarafan usus dengan Sistem Saraf Pusat (SSP) diputuskan. Kesimpulan serupa dipublikasikan Trendelenburg (1917); dan John Langley (1921) yang menyebutkan bahwa sistem saraf otonom terdiri dari simpatis, parasimpatis, dan sistem enteric. Subsistem enteric itu kemudian dinyatakan sebagai variasi subsistem parasimpatis.Dalam saluran pencernaan, kedua sistem itu berhubungan dengan rangkaian saraf yang membentuk plexus submucosus dan plexus myentericus, dan pengaruhnya terhadap sistem pencernaan diatur oleh Sistem Saraf Saluran Pencernaan (SSSP). Pengaturan oleh SSSP di proximal dan distal saluran pencernaan masih dintervensi oleh SSP (Goyal & Hirano, 1996; Gershon, 1998).Serabut saraf SSSP mengatur pergerakan organ serta waktu dan kuantitas sekresi kelenjar-kelenjar pencernaan. Jumlah sel saraf dalam SSSP sekitar 100 juta (Goyal & Hirano, 1996), setara dengan jumlah sel saraf di medulla spinalis. Karena itu SSSP dinilai sebagai suatu sistem yang derajatnya setara SSP sehingga dinamakan The Second Brain. Badan. Badan dan serabut saraf SSSP hanya dapat dipelajari dengan menggunakan mikroskop elektron (Gershon, 1998).Michael Gershon memperkenalkan peranan serotonin (5-hydroxytryptamine) sebagai neurotransmiter di SSSP yang mempengaruhi gerakan peristalstik dan sekresi kelenjar pencernaan. Sampai sekarang telah ditemukan sekitar 20 neurotransmiter di SSSP (Goyal & Hirano, 1996). Keberadaan SSSP menunjukkan bahwa pengaturan mekanisme kerja saluran pencernaan tidak sederhana
HI absorption associated to Norma's brightest cluster galaxy
No full text<b>External Organisations</b><br/>Commonwealth Scientific & Industrial Research Organisation; CSIRO - Australia Telescope National Facility<b>Associated Persons</b><br/>Baerbel Koribalski (Creator)Continuum and HI spectral cubes and multi-frequency synthesis continuum map towards the Norma cluster's brightest cluster galaxy, ESO137-G006. Cubes contain HI flux as a function of position and velocity. HI absorption has been detected to be associated to ESO137-G006. Telescope: The Australian Telescope Compact Array (ATCA) Centre RA: 16:15:04 Centre Dec: -60:54:26 Radius of cubes: 1 arcmin Radius of continuum map: 0.5 deg Synthesised Beam: 9 arcsec by 7 arcsec at 31 degrees Pixel Size: 2 arcsec RMS noise: 9 mJy/beam Frequency: 1396 MHz Velocity Resolution: 6.6 km/s Detection centre: 5460 km/s Detection width: 192 km/s Spectral noise: 9 mJy For more detailed information refer to Saraf, M et al 2022 (submitted to MNRAS
Diffusive author(s), cohesive author: Analysis of S/N (1994)
No full textThis study indicates the ways in which various aspects of the author(s) are brought forth in Dumb type’s performance art, the S/N production. Previous research has suggested a non-hierarchical organization of Dumb type and the absence of a “privileged author” in Dumb type’s collaborative work, S/N. However, the results that I have investigated from member’s interviews on the creative process of S/N along with my analysis of the recorded images of S/N, indicate a different aspect of the author(s). First, S/N was created through, so to speak, the collective ideas of the members of Dumb type. Further, S/N has at least nine quotations from previous performances, installations, and printed writings, besides the work-in-progress technique. Explicating one of the “author functions” as given by Michel Foucault, each text has plural subjects of the author. However, it has been revealed from members’ interviews that Teiji Furuhashi had a decision-making role in selecting the members’ ideas within the performance. Since then, S/N has had plural subjects of creation; however, Furuhashi is one of the subjects of creation along with the “privileged author.” S/N has plural authors (diffusive authors) yet at the same time, it has a “privileged author,” Teiji Furuhashi (cohesive author)
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Study of Astrophysical s-Process Neutron Capture Reactions at the High-Intensity SARAF-LiLiT Neutron Source
No full textWe report on recent experiments at the Soreq Applied Research Accelerator Facility Liquid-Lithium Target (SARAF-LiLiT) laboratory dedicated to the study of s-process neutron capture reactions. The kW-power proton beam at 1.92 MeV (1-2 mA) from SARAF Phase I yields high-intensity 30 keV quasi-Maxwellian neutrons (3-5×1010 n/s). The high neutron intensity enables Maxwellian averaged cross sections (MACS) measurements of low-abundance or radioactive targets. Neutron capture reactions on the important s-process branching points 147Pm and 171Tm were investigated by activation in the LiLiT neutron beam and γ-measurements of their decay products. MACS values at 30 keV extracted from the experimental spectrum-averaged cross sections are obtained and will be discussed. The Kr region, at the border between the so-called weak and strong s-process was also investigated. Atom Trap Trace Analysis (ATTA) was used for the first time for the measurement of a nuclear reaction cross section. After activation in the quasi-Maxwellian neutron flux at SARAF-LiLiT, isotopic ratios were determined for 81Kr(230 ky)/80Kr and 85gKr(10.8 y)/84Kr. The latter ratio was confirmed both by low-level β counting and γ spectrometry. The shorter-lived capture products 79,85m,87Kr were detected by γ -spectrometry and the corresponding neutron-capture MACS of the respective target nuclei 78,84,86Kr were determined. The MACS of the 80Kr(n, γ)81Kr and 84Kr(n, γ)85gKr reactions are still under study. The partial MACS leading to 85mKr(4.5 h) measured in this experiment has interesting implications since this state decays preferentially by γ decay (79%) to 85Rb on a faster time scale than does 85gKr and behaves thus as an s-process branching point
Calcium Homeostasis Disrupted—How Store-Operated Calcium Entry Factor SARAF Silencing Impacts HepG2 Liver Cancer Cells
No full textHepatocellular carcinoma (HCC), a highly aggressive liver malignancy, is often associated with disrupted calcium homeostasis. Store-operated calcium entry (SOCE), involving components such as STIM1, Orai1, and SARAF, plays a critical role in calcium signaling and cancer progression. While STIM1 and Orai1 have been extensively studied, SARAF’s role as a negative regulator of SOCE in HCC remains poorly understood. This preliminary study investigated SARAF’s effects on calcium homeostasis, proliferation, and migration in HepG2 liver cancer cells, providing initial evidence of its tumor-suppressive role. SARAF expression was modulated using siRNA knockdown and overexpression plasmids, with validation by qRT-PCR. Functional assays demonstrated that SARAF silencing increased proliferation by 50% and migration by 40% (p < 0.05), while SARAF overexpression reduced proliferation by 50% and migration by 45% (p < 0.01), highlighting its tumor-suppressive role. Intracellular calcium levels, elevated in HepG2 cells, were partially restored by SARAF overexpression, though SARAF silencing did not further disrupt calcium regulation. These findings suggest that SARAF negatively regulates proliferation and migration in HCC, potentially through its role in maintaining calcium homeostasis. SARAF represents a promising therapeutic target in HCC. Future studies should explore the downstream molecular mechanisms governing SARAF’s effects, investigate its role in other cancers, and assess its clinical potential for liver cancer therapy
- …
