Candidates of z ~ 5.5--7 Galaxies in the HST Ultra Deep Field

We report results from our $z\simeq 5.5$--7 galaxy search in the HST Ultra Deep Field (UDF). Using the 400-orbit of ACS data, we found 108 plausible $5.5\leq z\leq 6.5$ (or $z\simeq 6$ for short) candidates to $m_{AB}(z_{850})=30.0$ mag. The contamination to the sample, either due to image artifacts or known types of astronomical objects, is likely negligible. The inferred surface densities of $z\simeq 6$ galaxies are consistent with our earlier predictions from $m_{AB}(z_{850})=26.5$ to 28.5 mag. After correcting for detection incompleteness, the counts of $z\simeq 6$ candidates to $m_{AB}(z_{850})=29.2$ mag suggests that the faint-end slope of the galaxy luminosity function (LF) at this redshift is likely between $\alpha=-1.8$ and -1.9, which is sufficient to account for the entire Lyman photon budget necessary to complete the reionization of the universe at $z\simeq 6$. We also searched for $z\simeq 6.5$--7 candidates using the UDF NICMOS data, and have found four candidates to $J_{110}=27.2$ mag. However, the infrared colors of three candidates cannot be easily explained by galaxies in this redshift range. We tentatively derive an upper limit to the cumulative surface density of galaxies at $z\simeq 7$ of 0.36 per arcmin$^2$ to $J_{110}=26.6$ mag, which suggest a noticeable drop in the LF amplitude from $z\simeq 6$ to $z\simeq 7$.Comment: accepted for publication in ApJL (submitted March 17 2004, accepted July 20 2004

The Major Sources of the Cosmic Reionizing Background at z ~ 6

In this paper, we address which sources contributed most of the reionizing photons. Our argument assumes that the reionization ended around z ~ 6 and that it was a relatively quick process, i.e., that there was a non-negligible fraction of neutral hydrogen in the Universe at somewhat earlier epochs. Starting from our earlier estimate of the luminosity function (LF) of galaxies at z ~ 6, we quantitatively show that the major sources of reionization are most likely galaxies with L < L*. Our approach allows us to put stronger constraints to the LF of galaxies at z ~ 6. To have the Universe completely ionized at this redshift, the faint-end slope of the LF should be steeper than $\alpha=-1.6$, which is the value measured at lower redshifts (z ~ 3), unless either the normalization (Phi*) of the LF or the clumping factor of the ionized hydrogen has been significantly underestimated. If Phi* is actually lower than what we assumed by a factor of two, a steep slope close to $\alpha=-2.0$ is required. Our LF predicts a total of 50 -- 80 z ~ 6 galaxies in the HST Ultra Deep Field (UDF) to a depth of AB=28.4 mag, which can be used to constraint both Phi* and $\alpha$. We conclude that the least luminous galaxies existing at this redshift should reach as low as some critical luminosity in order to accumulate the entire reionizing photon budget. On the other hand, the existence of significant amounts of neutral hydrogen at slightly earlier epochs, e.g. z ~ 7, requires that the least luminous galaxies should not be fainter than another critical value (i.e., the LF should cut-off at this point).Comment: ApJL in press (Jan 1, 2004 issue

Wearable flexible lightweight modular RFID tag with integrated energy harvester

A novel wearable radio frequency identification (RFID) tag with sensing, processing, and decision-taking capability is presented for operation in the 2.45-GHz RFID superhigh frequency (SHF) band. The tag is powered by an integrated light harvester, with a flexible battery serving as an energy buffer. The proposed active tag features excellent wearability, very high read range, enhanced functionality, flexible interfacing with diverse low-power sensors, and extended system autonomy through an innovative holistic microwave system design paradigm that takes antenna design into consideration from the very early stages. Specifically, a dedicated textile shorted circular patch antenna with monopolar radiation pattern is designed and optimized for highly efficient and stable operation within the frequency band of operation. In this process, the textile antenna's functionality is augmented by reusing its surface as an integration platform for light-energy-harvesting, sensing, processing, and transceiver hardware, without sacrificing antenna performance or the wearer's comfort. The RFID tag is validated by measuring its stand-alone and on-body characteristics in free-space conditions. Moreover, measurements in a real-world scenario demonstrate an indoor read range up to 23 m in nonline-of-sight indoor propagation conditions, enabling interrogation by a reader situated in another room. In addition, the RFID platform only consumes 168.3 mu W, when sensing and processing are performed every 60 s

Harmonic balance surrogate-based immunity modeling of a nonlinear analog circuit

A novel harmonic balance surrogate-based technique to create fast and accurate behavioral models predicting, in the early design stage, the performance of nonlinear analog devices during immunity tests is presented. The obtained immunity model hides the real netlist, reduces the simulation time, and avoids expensive and time-consuming measurements after tape-out, while still providing high accuracy. The model can easily be integrated into a circuit simulator together with additional subcircuits, e.g., board and package models, as such allowing to efficiently reproduce complete immunity test setups during the early design stage and without disclosing any intellectual property. The novel method is validated by means of application to an industrial case study, being an automotive voltage regulator, clearly showing the technique's capabilities and practical advantages

Feasibility of a Manualized Mindful Yoga Intervention for Patients With Chronic Mood Disorders

Chronic mood disorders pose an important mental health problem. Individuals with these disorders experience a significant impairment, often fail to seek help, and their illnesses frequently do not respond to treatment. It is therefore important to develop innovative and attractive treatments for these disorders. Mindful yoga represents a promising treatment approach. This pilot study tested the feasibility of a 9-week manualized mindful yoga intervention for patients with chronic mood disorders. Eleven patients receiving standard treatment were recruited to complete a 9-week mindful yoga intervention. Qualitative methods were used to assess patients' experiences of the intervention and quantitative methods were used to assess psychological distress and mechanisms that play a role in chronic mood disorders. Eight patients completed the intervention and rated the overall quality of the intervention with a mean score of 8.8 (range of 8 to 9, using a scale of 1 to 10). All participants reported a reduction in psychological distress and no adverse events. Among the mechanisms that play a role in chronic mood disorders, the most potentially promising effects from the intervention were found for worry, fear of depression and anxiety, rumination, and areas related to body awareness, such as trusting bodily experiences and not distracting from sensations of discomfort. A 9-week mindful yoga intervention appears to be a feasible and attractive treatment when added to treatment as usual for a group of patients with chronic mood disorders. A randomized controlled trial to study the effects of mindful yoga is recommended

Use of the atmospheric generators for capnophilic bacteria Genbag-CO2 for the evaluation of in vitro Plasmodium falciparum susceptibility to standard anti-malarial drugs

Background: The aim of this study was to evaluate the cultivation system in which the proper atmospheric conditions for growing Plasmodium falciparum parasites were maintained in a sealed bag. The Genbag (R) system associated with the atmospheric generators for capnophilic bacteria Genbag CO2 (R) was used for in vitro susceptibility test of nine standard anti-malarial drugs and compared to standard incubator conditions. Methods: The susceptibility of 36 pre-identified parasite strains from a wide panel of countries was assessed for nine standard anti-malarial drugs (chloroquine, quinine, mefloquine, monodesethylamodiaquine, lumefantrine, dihydroartemisinin, atovaquone and pyrimethamine) by the standard 42-hour H-3-hypoxanthine uptake inhibition method using the Genbag CO2 (R) system and compared to controlled incubator conditions (5% CO2 and 10% O-2). Results: The counts per minute values in the control wells in incubator atmospheric conditions (5% CO2 and 10% O-2) were significantly higher than those of Genbag (R) conditions (2738 cpm vs 2282 cpm, p < 0.0001). The geometric mean IC50 estimated under the incubator atmospheric conditions was significantly lower for atovaquone (1.2 vs 2.1 nM, p = 0.0011) and higher for the quinolines: chloroquine (127 vs 94 nM, p < 0.0001), quinine (580 vs 439 nM, p < 0.0001), monodesethylamodiaquine (41.4 vs 31.8 nM, p < 0.0001), mefloquine (57.5 vs 49.7 nM, p = 0.0011) and lumefantrine (23.8 vs 21.2 nM, p = 0.0044). There was no significant difference of IC50 between the 2 conditions for dihydroartemisinin, doxycycline and pyrimethamine. To reduce this difference in term of anti-malarial susceptibility, a specific cut-off was estimated for each drug under Genbag (R) conditions by regression. The cut-off was estimated at 77 nM for chloroquine (vs 100 nM in 10% O-2), 611 nM for quinine (vs 800 nM), 30 nM for mefloquine (vs 30 nM), 61 nM for monodesethylamodiaquine (vs 80 nM) and 1729 nM for pyrimethamine (vs 2000 nM). Conclusions: The atmospheric generators for capnophilic bacteria Genbag CO2 (R) is an appropriate technology that can be transferred to the field for epidemiological surveys of drug-resistant malaria. The present data suggest the importance of the gas mixture on in vitro microtest results for anti-malarial drugs and the importance of determining the microtest conditions before comparing and analysing the data from different laboratories and concluding on malaria resistance

Gut microbiota, metabolism and psychopathology:A critical review and novel perspectives

Psychiatric disorders are often associated with metabolic comorbidities. However, the mechanisms through which metabolic and psychiatric disorders are connected remain unclear. Pre-clinical studies in rodents indicate that the bidirectional signaling between the intestine and the brain, the so-called microbiome-gut-brain axis, plays an important role in the regulation of both metabolism and behavior. The gut microbiome produces a vast number of metabolites that may be transported into the host and play a part in homeostatic control of metabolism as well as brain function. In addition to short chain fatty acids, many of these metabolites have been identified in recent years. To what extent both microbiota and their products control human metabolism and behavior is a subject of intense investigation. In this review, we will discuss the most recent findings concerning alterations in the gut microbiota as a possible pathophysiological factor for the co-occurrence of metabolic comorbidities in psychiatric disorders