3,997 research outputs found
One-way coherent imaging through a distorting medium using four-wave mixing
A proposal and an analysis are presented for imaging through a distorting medium using field multiplication by four-wave mixing
Impact of carrier heating on SOA transmission dynamics for wavelength conversion
Complex-valued time-resolved transmission characteristics of a semiconductor optical amplifier (SOA) are measured using a spectrogram technique. A relatively simple traveling-wave density matrix model is implemented that accurately captures the evolution of complex index due to stimulated emission and carrier heating. The model shows good agreement with experimental spectrogram data
When to go local, when to go edible: Trade, technology and food security
We develop a variation of the Grossman-Helpman Protection for Sale model, where organized groups, representing various sectors of the economy, influence government policy. In particular, this paper focuses on the rise of food prices and a greater level of influence of a food sector lobby, relative to other political lobbies- and general consumer welfare. Governments, when considering their objectives, must consider food security along with consumer welfare and the objectives of other special-interest groups. We find that, as government emphasizes domestic food security, lobbies representing the food sector gain influence at the expense of other, non-food lobbies and the general population. In this framework, technology plays an important role. Technology, by increasing the rate at which the economy expands, allows government to reap the rewards of special interest participation in policy formation while increasing national welfare
Simple rules for optimizing asymmetries in SOA-based Mach-Zehnder wavelength converters
We present an analysis of semiconductor optical amplifier (SOA) based differential Mach-Zehnder wavelength converters with a specific focus on optimizing performance through intentional asymmetries in optical power splitting, SOA bias, and interferometer phase bias.  By introducing a simple conceptual framework for understanding the amplifier pulse dynamics, two simple yet effective design rules are derived. These design rules are validated using pseudo-random code in a comprehensive computer model, demonstrating the performance penalties that result when attempting optimization using only unequal SOA biasing or phase biasing. This work illustrates that dramatic improvements in extinction and eye margin can be achieved with optimized splitter asymmetries, and has significant implications for improved network performance and converter cascadability
Pepducin-mediated cardioprotection via β-arrestin-biased β2-adrenergic receptor-specific signaling
Reperfusion as a therapeutic intervention for acute myocardial infarction-induced cardiac injury itself induces further cardiomyocyte death. β-arrestin (βarr)-biased β-adrenergic receptor (βAR) activation promotes survival signaling responses in vitro; thus, we hypothesize that this pathway can mitigate cardiomyocyte death at the time of reperfusion to better preserve function. However, a lack of efficacious βarr-biased orthosteric small molecules has prevented investigation into whether this pathway relays protection against ischemic injury in vivo. We recently demonstrated that the pepducin ICL1-9, a small lipidated peptide fragment designed from the first intracellular loop of β2AR, allosterically engaged pro-survival signaling cascades in a βarr-dependent manner in vitro. Thus, in this study we tested whether ICL1-9 relays cardioprotection against ischemia/reperfusion (I/R)-induced injury in vivo.
Methods: Wild-type (WT) C57BL/6, β2AR knockout (KO), βarr1KO and βarr2KO mice received intracardiac injections of either ICL1-9 or a scrambled control pepducin (Scr) at the time of ischemia (30 min) followed by reperfusion for either 24 h, to assess infarct size and cardiomyocyte death, or 4 weeks, to monitor the impact of ICL1-9 on long-term cardiac structure and function. Neonatal rat ventricular myocytes (NRVM) were used to assess the impact of ICL1-9 versus Scr pepducin on cardiomyocyte survival and mitochondrial superoxide formation in response to either serum deprivation or hypoxia/reoxygenation (H/R) in vitro and to investigate the associated mechanism(s).
Results: Intramyocardial injection of ICL1-9 at the time of I/R reduced infarct size, cardiomyocyte death and improved cardiac function in a β2AR- and βarr-dependent manner, which led to improved contractile function early and less fibrotic remodeling over time. Mechanistically, ICL1-9 attenuated mitochondrial superoxide production and promoted cardiomyocyte survival in a RhoA/ROCK-dependent manner. RhoA activation could be detected in cardiomyocytes and whole heart up to 24 h post-treatment, demonstrating the stability of ICL1-9 effects on βarr-dependent β2AR signaling.
Conclusion: Pepducin-based allosteric modulation of βarr-dependent β2AR signaling represents a novel therapeutic approach to reduce reperfusion-induced cardiac injury and relay long-term cardiac remodeling benefits
The Effect of Movement Therapy on Negative Symptoms in Schizophrenia - A Multicenter Randomized Controlled Trial
Objective: Negative symptoms of patients with Schizophrenia are resistant to
medical treatment or conventional group therapy. Understanding schizophrenia
as a form of disembodiment of the self, a number of scientists have argued
that the approach of embodiment and associated embodied therapies, such as
Dance and Movement Therapy (DMT) or Body Psychotherapy (BPT), may be more
suitable to explain the psychopathology underlying the mental illness and to
address its symptoms. Hence the present randomized controlled trial
(DRKS00009828, http://apps.who.int/trialsearch/) aimed to examine the
effectiveness of manualized movement therapy (BPT/DMT) on the negative
symptoms of patients with schizophrenia. Method:A total of 68 out-patients
with a diagnosis of a schizophrenia spectrum disorder were randomly allocated
to either the treatment (n = 44, 20 sessions of BPT/DMT) or the control
condition [n = 24, treatment as usual (TAU)]. Changes in negative symptom
scores on the Scale for the Assessment of Negative Symptoms (SANS) were
analyzed using Analysis of Covariance (ANCOVA) with Simpson-Angus Scale (SAS)
scores as covariates in order to control for side effects of antipsychotic
medication. Results:After 20 sessions of treatment (BPT/DMT or TAU), patients
receiving movement therapy had significantly lower negative symptom scores
(SANS total score, blunted affect, attention). Effect sizes were moderate and
mean symptom reduction in the treatment group was 20.65%. Conclusion:The study
demonstrates that embodied therapies, such as BPT/DMT, are highly effective in
the treatment of patients with schizophrenia. Results strongly suggest that
BPT/DMT should be embedded in the daily clinical routine
Identification, Biology, Impacts, and Management of Stink Bugs (Hemiptera: Heteroptera: Pentatomidae) of Soybean and Corn in the Midwestern United States
Stink bugs (Hemiptera: Heteroptera: Pentatomidae) are an emerging threat to soybean and corn production in the midwestern United States. An invasive species, the brown marmorated stink bug, Halyomorpha halys (Sta° l), is spreading through the region. However, little is known about the complex of stink bug species associated with corn and soybean in the midwestern United States. In this region, particularly in the more northern states, stink bugs have historically caused only infrequent impacts to these crops. To prepare growers and agricultural professionals to contend with this new threat, we provide a review of stink bugs associated with soybean and corn in the midwestern United States. Descriptions and images of common stink bug species are provided as a diagnostic aid. The biologies and impacts of stink bugs to crops are discussed, with particular attention to differences among species. Based primarily on information from southern states, scouting, thresholds, and insecticide-based management of these pests are discussed. It is hoped that this review will provide stakeholders sufficient information for management of these pests, until more region-specific research can be performed on stink bugs in soybean and corn in the midwestern United States
Butterfly hysteresis loop at non-zero bias field in antiferromagnetic molecular rings: cooling by adiabatic magnetization
At low temperatures, the magnetization of the molecular ferric wheel NaFe
exhibits a step at a critical field due to a field-induced
level-crossing. By means of high-field torque magnetometry we observed a
hysteretic behavior at the level-crossing with a characteristic butterfly shape
which is analyzed in terms of a dissipative two-level model. Several unusual
features were found. The non-zero bias field of the level-crossing suggests the
possibility of cooling by adiabatic magnetization.Comment: 4 pages, 5 figures, REVTEX4, to appear in PR
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