Heralded photon amplification for quantum communication

Heralded noiseless amplification based on single-photon sources and linear optics is ideally suited for long-distance quantum communication tasks based on discrete variables. We experimentally demonstrate such an amplifier, operating at telecommunication wavelengths. Coherent amplification is performed with a gain of G=1.98+/-0.2, for a state with a maximum expected gain G=2. We also demonstrate that there is no need for a stable phase reference between the initial signal state and the local auxiliary photons used by the amplifier. These results highlight the potential of heralded quantum amplifiers for long-distance quantum communication, and bring device-independent quantum key distribution one step closer.Comment: 5 pages, 4 figure

Chemical Equilibrium Abundances in Brown Dwarf and Extrasolar Giant Planet Atmospheres

We calculate detailed chemical abundance profiles for a variety of brown dwarf and extrasolar giant planet atmosphere models, focusing in particular on Gliese 229B, and derive the systematics of the changes in the dominant reservoirs of the major elements with altitude and temperature. We assume an Anders and Grevesse (1989) solar composition of 27 chemical elements and track 330 gas--phase species, including the monatomic forms of the elements, as well as about 120 condensates. We address the issue of the formation and composition of clouds in the cool atmospheres of substellar objects and explore the rain out and depletion of refractories. We conclude that the opacity of clouds of low--temperature ($\le$900 K), small--radius condensibles (specific chlorides and sulfides), may be responsible for the steep spectrum of Gliese 229B observed in the near infrared below 1 \mic. Furthermore, we assemble a temperature sequence of chemical transitions in substellar atmospheres that may be used to anchor and define a sequence of spectral types for substellar objects with T$_{eff}$s from $\sim$2200 K to $\sim$100 K.Comment: 57 pages total, LaTeX, 14 figures, 5 tables, also available in uuencoded, gzipped, and tarred form via anonymous ftp at www.astrophysics.arizona.edu (cd to pub/burrows/chem), submitted to Ap.

Mercury removal in wastewater by iron oxide nanoparticles

Mercury is one of the persistent pollutants in wastewater; it is becoming a severe environmental and public health problem, this is why nowadays its removal is an obligation. Iron oxide nanoparticles are receiving much attention due to their properties, such as: great biocompatibility, ease of separation, high relation of surface-area to volume, surface modifiability, reusability, excellent magnetic properties and relative low cost. In this experiment, Fe3O4 and γ-Fe2O3 nanoparticles were synthesized using iron salts and NaOH as precipitation agents, and Aloe Vera as stabilizing agent; then these nanoparticles were characterized by three different measurements: first, using a Zetasizer Nano ZS for their size estimation, secondly UV-visible spectroscopy which showed the existence of resonance of plasmon at λmax∼360 nm, and lastly by Scanning Electron Microscopy (SEM) to determine nanoparticles form. The results of this characterization showed that the obtained Iron oxides nanoparticles have a narrow size distribution (∼100nm). Mercury removal of 70% approximately was confirmed by atomic absorption spectroscopy measurements

A New Pleiades Member at the Lithium Substellar Boundary

We present the discovery of an object in the Pleiades open cluster, named Teide 2, with optical and infrared photometry which place it on the cluster sequence slightly below the expected substellar mass limit. We have obtained low- and high-resolution spectra that allow us to determine its spectral type (M6), radial velocity and rotational broadening; and to detect H$_\alpha$ in emission and Li I 670.8 nm in absorption. All the observed properties strongly support the membership of Teide 2 into the Pleiades. This object has an important role in defining the reappearance of lithium below the substellar limit in the Pleiades. The age of the Pleiades very low-mass members based on their luminosities and absence or presence of lithium is constrained to be in the range 100--120 Myr.Comment: 17 pages, 3 figure

Additive-multiplicative stochastic models of financial mean-reverting processes

We investigate a generalized stochastic model with the property known as mean reversion, that is, the tendency to relax towards a historical reference level. Besides this property, the dynamics is driven by multiplicative and additive Wiener processes. While the former is modulated by the internal behavior of the system, the latter is purely exogenous. We focus on the stochastic dynamics of volatilities, but our model may also be suitable for other financial random variables exhibiting the mean reversion property. The generalized model contains, as particular cases, many early approaches in the literature of volatilities or, more generally, of mean-reverting financial processes. We analyze the long-time probability density function associated to the model defined through a It\^o-Langevin equation. We obtain a rich spectrum of shapes for the probability function according to the model parameters. We show that additive-multiplicative processes provide realistic models to describe empirical distributions, for the whole range of data.Comment: 8 pages, 3 figure

On the relationship between pump chirp and single-photon chirp in spontaneous parametric downconversion

We study the chronocyclic character, i.e. the joint temporal and spectral properties, of the single-photon constituents of photon pairs generated by spontaneous parametric down conversion. In particular we study how single photon properties, including purity and single-photon chirp, depend on photon pair properties, including the type of signal-idler spectral and correlations and the level of pump chirp.Comment: 13 pages, 6 figure

Implement Smart Sensors With Wireless Communication Protocols With Embedded Microcontrollers in a Capstone Project Design

Wireless communication has become popular and widely used in our daily lives. Their applications are: Cellular Wireless for telephone systems, data collection, voice communication, and other mobile or extremely remote devices, Bluetooth for low-power applications in short range and moderate date bandwidth, Proprietary ISM (industrial, scientific, medical) protocols used in open frequency bands from 260 to 470 MHz, 902 to 928 MHz, and 2.4GHz, 802.11/WiFi in wireless data communications, 802.15/ZigBee for mesh networks of sensors and controllers, and Z-Wave for low speed wireless protocol of home electronics devices to intercommunicate using reliable protocol that easily travels through walls, floors, and cabinets1. Sensors with embedded intelligence and integrated with cost effective wireless protocols have been recognized as smart sensors in many applications, such as smart home appliances, home automation, green technology in energy conservation and harvesting, and remote data logging etc2. This application project is implemented in the classification between Proprietary ISM, ZigBee, and Z-Wave wireless applications. It is built based on the MRF24J40MA (2.4GHz RF modules) that follows the IEEE 802.15.4TM-2003 rules7, standards, and software protocols designs with SPI (Serial Peripheral Interface)9 interfacing to a PIC16F877A microcontroller. The project uses three 2.4 GHz RF modules (MRF24J40MA), and three PIC16F877A units hosted in three previously developed low cost PIC microcontroller training systems3. The sensor stations are designed as Slave units and responsible for conditioning and reporting temperature, humidity, and atmospheric pressure. The control unit is categorized as a Master station and responsible for interacting with user/host to decide when, where, and how to report the data to the inquiries. In addition to sensors on the Slaves station, there are assistances from real time clock and external serial EEPROM devices to provide time stamped real time data for future inquiry from the Master. All the communications between the Master and multiple Slaves are through wireless RF signals with customized software protocol designs4

Biomimetics of microducts in three-dimensional bacterial nanocellulose biomaterials for soft tissue regenerative medicine

The demand for solid organs is increasing worldwide, regenerative medicine aims to develop organs that can replace their human counterparts. In this regard, this study describes a novel biomimetic-based methodology for the incorporation of microducts in 3D bacterial nanocellulose (BNC-3D) biomaterials. Although BNC is a biomaterial that has been used as a scaffold for cell culture purposes, it does not have the microduct structure that solid organs required to maintain cell viability. This study aims to biomimicry the microduct structure (blood vessels) in BNC using a corroded porcine kidney in epoxy resin during BNC synthesis. The resin mold was incorporated into the biological process of producing BNC-3D. After the BNC fermentation, the resin was removed using a novel method (acid hydrolysis) to expose the blood vessels constructs. BNC-3D and BNC-3D with microducts (BNC-3DM) were analyzed using electronic microscopy, infrared analysis, thermogravimetric and biological analysis. Results show that biomaterials biomimicry the blood vessels of the reference organ, moreover, the BNC chemical and morphological properties of BNC was not affected in the biomimetic process. Regarding cell behavior, cell viability was not affected by the incorporation of the microducts, and it was proven that viable cells adhere to the microducts surface, reproducing their shape and migrate into the biomaterial up to 245 mu m for 8 days of culture. To conclude, the data demonstrate the potential of biomimetic in BNC for regenerative medicine, in which the microducts transport fluids (blood, nutrients, and waste products) from and to engineered solid organs via animal counterparts. Graphic abstract The graphical abstract represents the structural modification of bacterial nanocellulose (BNC) with the inclusion of microducts and microporosities. Furthermore, it represents the usefulness of the microducts in future applications, where, they can be used for nutrients inlet to feed the cells and to remove the wastes from the developed tissue, same as do the blood vessels. [GRAPHICS]

Modulation of Cytokine and Cytokine Receptor/Antagonist by Treatment with Doxycycline and Tetracycline in Patients with Dengue Fever

Dengue virus infection can lead to dengue fever (DF) or dengue hemorrhagic fever (DHF). Disease severity has been linked to an increase in various cytokine levels. In this study, we evaluated the effectiveness of doxycycline and tetracycline to modulate serum levels of IL-6, IL-1B, and TNF and cytokine receptor/receptor antagonist TNF-R1 and IL-1RA in patients with DF or DHF. Hospitalized patients were randomized to receive standard supportive care or supportive care combined with doxycycline or tetracycline therapy. Serum cytokine and cytokine receptor/antagonist levels were determined at the onset of therapy and after 3 and 7 days. Cytokine and cytokine receptor/antagonist levels were substantially elevated at day 0. IL-6, IL-1β, and TNF remained at or above day 0 levels throughout the study period in untreated patients. Treatment with tetracycline or doxycycline resulted in a significant decline in cytokine levels. Similarly, IL-1RA and TNF-R1 serum concentrations were elevated at baseline and showed a moderate increase among untreated patients. Both drugs resulted in a significant rise in IL-1Ra levels by day 3 in patients. In contrast, treatment did not affect a similar result for TNF-R1. When compared to the control group, however, a significant rise post-treatment was seen upon intragroup analysis. Further analysis demonstrated that doxycycline was significantly more effective at modulating cytokine and cytokine receptor/antagonist levels than tetracycline