Time structure of gamma-ray signals generated in line-of-sight interactions of cosmic rays from distant blazars

Blazars are expected to produce both gamma rays and cosmic rays. Therefore, observed high-energy gamma rays from distant blazars may contain a significant contribution from secondary gamma rays produced along the line of sight by the interactions of cosmic-ray protons with background photons. Unlike the standard models of blazars that consider only the primary photons emitted at the source, models which include the cosmic-ray contribution predict that even ~10 TeV photons should be detectable from distant objects with redshifts as high as z> 0.1. Secondary photons contribute to signals of point sources only if the intergalactic magnetic fields are very small, below ~10 femtogauss, and their detection can be used to set upper bounds on magnetic fields along the line of sight. Secondary gamma rays have distinct spectral and temporal features. We explore the temporal properties of such signals using a semi-analytical formalism and detailed numerical simulations, which account for all the relevant processes, including magnetic deflections. In particular, we elucidate the interplay of time delays coming from the proton deflections and from the electromagnetic cascade, and we find that, at multi-TeV energies, secondary gamma-rays can show variability on timescales of years for femtogauss magnetic fields.Comment: 25 pages, 9 figure

TeV gamma rays from blazars beyond z=1?

At TeV energies, the gamma-ray horizon of the universe is limited to redshifts z<<1, and, therefore, any observation of TeV radiation from a source located beyond z=1 would call for a revision of the standard paradigm. While robust observational evidence for TeV sources at redshifts z>1 is lacking at present, the growing number of TeV blazars with redshifts as large as z~0.5 suggests the possibility that the standard blazar models may have to be reconsidered. We show that TeV gamma rays can be observed even from a source at z>1, if the observed gamma rays are secondary photons produced in interactions of high-energy protons originating from the blazar jet and propagating over cosmological distances almost rectilinearly. This mechanism was initially proposed as a possible explanation for the TeV gamma rays observed from blazars with redshifts z~0.2, for which some other explanations were possible. For TeV gamma-ray radiation detected from a blazar with z>1, this model would provide the only viable interpretation consistent with conventional physics. It would also have far-reaching astronomical and cosmological ramifications. In particular, this interpretation would imply that extragalactic magnetic fields along the line of sight are very weak, in the range 0.01 < fG < 10 fG, assuming random fields with a correlation length of 1 Mpc, and that acceleration of E> 0.1 EeV protons in the jets of active galactic nuclei can be very effective.Comment: 8 pages, 4 figure

Photosynthesis and Light Activation of Ribulose 1,5-bisphosphate Carboxylase in the Presence of Starch

Limitation of photosynthesis and light activation of ribulose, 1,5-bisphosphate carboxylase (RuBPCO) were examined in the 5th leaf of seedlings of red clover (Trifolium pratense L. cv. Renova) for 5 d following an increase in photosynthetic photon flux density (PPFD) from 200 to 550μmol quanta m−2 s−1. Net photosynthesis and its stimulation at 2.0 kPa O2 initial activity of rapidly extracted RuBPCO, standard activity of RuBPCO after incubation of the extracts in the presence of CO2, Mg2+, and inorganic phosphate and contents of soluble protein, starch, soluble sugars, and various photosynthetic metabolites were determined. Photosynthesis decreased and starch content increased. No decrease in photosynthesis was found if, when PPFD was increased, all leaves except the investigated 5th leaf were removed, suggesting that the decrease in photosynthesis was due to accumulated carbohydrates. The stimulation of photosynthesis at 2.0 kPa O2 did not decrease and the ratio of the total foliar steady-state contents of triose phosphate to 3-phosphoglycerate increased suggesting that the decrease in photosynthesis was not due to limiting inorganic phosphate in chloroplasts. Intercellular CO2 partial pressure and RuBP content were not decreased. Nevertheless, the ratio of photosynthesis to initial RuBPCO activity decreased, suggesting that the catalysis per active RuBPCO site was decreased. The increase in PPFD in the growth cabinet and the PPFD at which leaves were preconditioned for 1 h, affected not only initial activity but also the standard activity of RuBPCO. The results suggest that a varying proportion of RuBPCO was bound to membranes and was contained in the insoluble fraction of the extracts. A comparison of photosynthesis with extracted RuBPCO activity suggested that membrane bound RuBPCO did not contribute to photosynthetic CO2 fixation and that the binding and release to and from membranes modulated actual RuBPCO activity in viv

Borel versions of the Local Lemma and LOCAL algorithms for graphs of finite asymptotic separation index

Asymptotic separation index is a parameter that measures how easily a Borel graph can be approximated by its subgraphs with finite components. In contrast to the more classical notion of hyperfiniteness, asymptotic separation index is well-suited for combinatorial applications in the Borel setting. The main result of this paper is a Borel version of the Lov\'asz Local Lemma -- a powerful general-purpose tool in probabilistic combinatorics -- under a finite asymptotic separation index assumption. As a consequence, we show that locally checkable labeling problems that are solvable by efficient randomized distributed algorithms admit Borel solutions on bounded degree Borel graphs with finite asymptotic separation index. From this we derive a number of corollaries, for example a Borel version of Brooks's theorem for graphs with finite asymptotic separation index

Quantum thermodynamics of the driven resonant level model

We present a consistent thermodynamic theory for the resonant level model in the wide band limit, whose level energy is driven slowly by an external force. The problem of defining 'system' and 'bath' in the strong coupling regime is circumvented by considering as the 'system' everything that is influenced by the externally driven level. The thermodynamic functions that are obtained to first order beyond the quasistatic limit fulfill the first and second law with a positive entropy production, successfully connect to the forces experienced by the external driving, and reproduce the correct weak coupling limit of stochastic thermodynamics.Comment: Final version as publishe

Identifikasi Faktor Penyebab dan Dampak Change Order Pada Pelaksanaan Proyek Bidang Sumber Daya Air

Penelitian ini mengidentifikasi faktor penyebab dan dampak change order pada proyek pemerintah bidang sumber daya air yang berada pada Provinsi Sumatera Barat dengan menggunakan metode path analysis. Penelitian ini dilakukan dengan menyebar kuesioner kepada pihak-pihak yang terlibat pada pelaksanaan proyek bidang sumber daya air, diantaranya PPK, PPTK dan Pengawas. Hasil penelitian didapatkan faktor yang berpengaruh signifikan yaitu perubahan rencana dan ruang lingkup, faktor alam, koordinasi yang tidak baik antar pihak yang berkepentingan, dan masalah pembebasan lahan. Untuk variabel masalah pembebasan lahan tidak berpengaruh langsung terhadap frekuensi change order tetapi berpengaruh terhadap perubahan rencana dan ruang lingkup. Dampak CO lebih berpengaruh terhadap kinerja waku

Inside-Outside Duality of Entropy Evolution

We develop a Landauer-Büttiker theory of entropy evolution in time-dependent, strongly coupled electron systems. The formalism naturally avoids the problem of the system-bath distinction by defining the entropy current in the attached leads. This current can then be used to infer changes of the entropy of the system which we refer to as the inside-outside duality. We carry out this program in an adiabatic expansion up to first order beyond the quasistatic limit. When combined with particle and energy currents, as well as the work required to change an external potential, our formalism provides a full thermodynamic description, applicable to arbitrary noninteracting electron systems in contact with reservoirs. This provides a clear understanding of the relation between heat and entropy currents generated by time-dependent potentials and their connection to the occurring dissipation

Flow Cytometry and Polymerase Chain Reaction-Based Analyses of Minimal Residual Disease in Chronic Lymphocytic Leukemia

New therapeutic strategies developed recently for chronic lymphocytic leukemia (CLL) have led to remarkable treatment response rates and complete hematological remissions. This means highly sensitive and specific techniques are increasingly needed to evaluate minimal residual disease (MRD) in CLL patients. Quantitative MRD levels can be used as prognostic markers, where total MRD eradication is associated with prolonged survival. Nowadays, PCR and flow cytometry techniques used to detect MRD in CLL patients can generate reliable and quantitative results with the highest sensitivity. MRD Flow is based on four-color flow cytometry using specific antibody combinations. For allele specific oligonucleotide real-time quantification (ASO RQ) PCR individual primers are designed to detect a specific immunoglobulin heavy chain (IgH) rearrangement in each patient clone. Five comprehensive studies investigated and compared the sensitivity and specificity of both methods. Groups of patients receiving different therapies were analyzed at different time points to generate quantitative MRD levels and MRD kinetics. All studies confirmed that both methods generate equivalent results with regard to sensitivity and MRD quantification, although each method has advantages and disadvantages in the daily routine of a standard hematological laboratory. Here, we review these investigations and compare their results in the light of modern therapies