U.S. Citrus Import Demand: Seasonality and Substitution

Citrus fruits make up one-fifth of all fresh fruit consumed in the United States. Given the increasing importance of imported citrus in the diet of American consumers, it is perhaps surprising that no import demand analysis of U.S. citrus has been conducted. Using quarterly U.S. import data for six citrus commodities, we employed a demand systems model and evaluated aspects of seasonality. The results suggest wide variations in price responses to different types of imported citrus. The average amplitude and phase shift suggest that all citrus fruits exhibit some seasonality in their imports, likely a result of peak harvesting schedules of exporters.Fresh citrus, oranges, limes, lemons, grapefruit, mandarins, import demand, seasonality, Demand and Price Analysis, International Relations/Trade,

A New Class of non-Hermitian Quantum Hamiltonians with PT Symmetry

In a remarkable development Bender and coworkers have shown that it is possible to formulate quantum mechanics consistently even if the Hamiltonian and other observables are not Hermitian. Their formulation, dubbed PT quantum mechanics, replaces hermiticity by another set of requirements, notably that the Hamiltonian should be invariant under the discrete symmetry PT, where P denotes parity and T denotes time reversal. All prior work has focused on the case that time reversal is even (T^2 = 1). We generalize the formalism to the case of odd time reversal (T^2 = -1). We discover an analogue of Kramer's theorem for PT quantum mechanics, present a prototypical example of a PT quantum system with odd time reversal, and discuss potential applications of the formalism. Odd time reversal symmetry applies to fermionic systems including quarks and leptons and a plethora of models in nuclear, atomic and condensed matter physics. PT quantum mechanics makes it possible to enlarge the set of possible Hamiltonians that physicists could deploy to describe fundamental physics beyond the standard model or for the effective description of condensed matter phenomena.Comment: Replaced submitted version with accepted version; to appear in Phys Rev

Dynamical Decoupling in Optical Fibers: Preserving Polarization Qubits from Birefringent Dephasing

One of the major challenges in quantum computation has been to preserve the coherence of a quantum system against dephasing effects of the environment. The information stored in photon polarization, for example, is quickly lost due to such dephasing, and it is crucial to preserve the input states when one tries to transmit quantum information encoded in the photons through a communication channel. We propose a dynamical decoupling sequence to protect photonic qubits from dephasing by integrating wave plates into optical fiber at prescribed locations. We simulate random birefringent noise along realistic lengths of optical fiber and study preservation of polarization qubits through such fibers enhanced with Carr-Purcell-Meiboom-Gill (CPMG) dynamical decoupling. This technique can maintain photonic qubit coherence at high fidelity, making a step towards achieving scalable and useful quantum communication with photonic qubits.Comment: 8 pages, 5 figure

The 3 December 1988 Pasadena, California earthquake: Evidence for strike-slip motion on the Raymond fault

The Pasadena earthquake (M_L = 4.9) occurred on 3 December 1988, at a depth of 16 km. The hypocenters of the earthquake and its aftershocks define a east-northeast striking, steeply northwest-dipping surface that projects up to the active surficial trace of the Raymond fault. One of the nodal planes of the focal mechanism of the earthquake parallels the Raymond fault with left-lateral strike-slip movement on that plane, and is consistent with geomorphic and paleoseismic evidence that the Raymond fault is dominantly a left-lateral strike-slip fault. The existence of a component of sinistral slip along the Raymond fault had been suspected prior to the earthquake, but the northward dip of the fault and the prominent scarp along the western portion of its trace had led most workers to conclude that slip along the fault was dominantly reverse

Evaluating survey methods for bat roost detection in ecological impact assessment

International audienceThe disturbance, damage and destruction of roosts are key drivers of bat population declines worldwide. In countries where bats are protected by law, bat roost surveys are often required to inform ecological impact assessments. Yet, evidence-based information on survey methodology to detect bat roosts is crucially lacking, and failing to detect a roost can lead to serious errors during decision-making processes. Here, we assess the efficacy of bat roost surveys in buildings as implemented in the UK. These consist of a daytime inspection of buildings, followed by a series of acoustic surveys at dusk/dawn if during the daytime inspection evidence of bats is found, or if the absence of bats cannot be verified. We reviewed 155 ecological consultants’ reports to (1) compare survey outcome between daytime inspection and acoustic surveys and (2) determine the minimum sampling effort required during acoustic surveys to be confident that no bats are roosting within a building. We focused on two genera of bats most frequently found in buildings in Europe – Pipistrellus (crevice roosting species with high-intensity echolocation calls that can be easily detected by ultrasound detectors) and Plecotus (species that roost in open spaces and which emit faint echolocation calls that are difficult to detect). Daytime inspections were efficient in detecting open-roosting species such as Plecotus species but were likely to miss the presence of crevice-dwelling ones (here Pipistrellus species) which may lead to erroneous conclusions if no acoustic surveys are subsequently prescribed to confirm their absence. A minimum of three and four acoustic surveys are required to be 95% confident that a building does not host a roost of Pipistrellus species and Plecotus species, respectively, thus exceeding current recommendations. Overall, we demonstrated that reports submitted as part of an ecological impact assessment provide suitable data to test and improve survey methods

Adverse Childhood Life Events and Postpartum Mood Episodes in Bipolar Disorder

Background: The early postpartum has been established as a period of increased vulnerability for psychiatric mood illness. Women with bipolar disorder (BD) in particular are at elevated risk of postnatal depression (PND) and of postpartum psychosis (PP). Though adverse childhood life events (ACLEs) have been implicated in the aetiology of PND, this has rarely been studied in relation to PP. Furthermore, despite being at high risk of relapse following childbirth, little research has assessed the relationship between ACLEs and postnatal mood episodes (PNEs) exclusively in women with BD. Therefore, our aim was to explore associations between ACLEs and occurrence of both PND and PP in a large sample of women with BD. Methods: Participants were 665 parous women with BD who had been recruited into the Bipolar Disorder Research Network study. Diagnoses and lifetime psychopathology were obtained via a semi-structured interview (SCAN). Postnatal psychiatric history and experience of 7 ACLEs were also assessed. Where available, all information obtained at interview was confirmed from psychiatric case notes. Women were classified into three groups according to postnatal psychiatric history: 1) those who had experienced no postnatal mood episode (no PNE, n=224), 2) women with a history of PND (n=223) and 3) women who had experienced PP (n=208). A Pearson’s chi-square test was used to compare the prevalence of each type of ACLE between women in the no PNE group and those with a history of PND or PP. Results: Women with PND were significantly more likely to have experienced emotional, sexual or physical abuse in childhood compared with women who had no history of a PNE (p<0.05). In particular, childhood sexual abuse was reported significantly more in the PND than the no PNE group (P<0.05). In contrast, there were no significant differences in the frequency of reporting of any ACLEs between women who had no PNE and those with PP. Conclusions: Our findings indicate that childhood abuse, sexual abuse in particular, is associated with PND among women with BD. In contrast, we found no evidence for an association between any ACLE and PP, suggesting that biological factors are likely to play a more important role in the aetiology of psychosis in the early postpartum

Preliminary prediction of individual response to electroconvulsive therapy using whole-brain functional magnetic resonance imaging data.

Electroconvulsive therapy (ECT) works rapidly and has been widely used to treat depressive disorders (DEP). However, identifying biomarkers predictive of response to ECT remains a priority to individually tailor treatment and understand treatment mechanisms. This study used a connectome-based predictive modeling (CPM) approach in 122 patients with DEP to determine if pre-ECT whole-brain functional connectivity (FC) predicts depressive rating changes and remission status after ECT (47 of 122 total subjects or 38.5% of sample), and whether pre-ECT and longitudinal changes (pre/post-ECT) in regional brain network biomarkers are associated with treatment-related changes in depression ratings. Results show the networks with the best predictive performance of ECT response were negative (anti-correlated) FC networks, which predict the post-ECT depression severity (continuous measure) with a 76.23% accuracy for remission prediction. FC networks with the greatest predictive power were concentrated in the prefrontal and temporal cortices and subcortical nuclei, and include the inferior frontal (IFG), superior frontal (SFG), superior temporal (STG), inferior temporal gyri (ITG), basal ganglia (BG), and thalamus (Tha). Several of these brain regions were also identified as nodes in the FC networks that show significant change pre-/post-ECT, but these networks were not related to treatment response. This study design has limitations regarding the longitudinal design and the absence of a control group that limit the causal inference regarding mechanism of post-treatment status. Though predictive biomarkers remained below the threshold of those recommended for potential translation, the analysis methods and results demonstrate the promise and generalizability of biomarkers for advancing personalized treatment strategies

Health Communication as a Public Health Training and Workforce Development Issue

Effective communication is one of the core competencies for public health professionals and is required for local health department (LHD) accreditation. Public health communication specialists play a critical role as conduits of health information, particularly with regard to managing relationships with media and the message that is ultimately represented by news outlets. However, capacity for engagement with traditional media in community health improvement at the local level has not been well-described. As part of a larger study examining the use and impact of the County Health Rankings in North Carolina, LHD media staffing and interaction with traditional media were examined through a cross-sectional, online survey, administered to North Carolina LHDs. Results indicate that most LHDs in North Carolina have staff designated to work with media, but few have dedicated staff or staff with an educational background in mass communication. Most communication staff enter their position with less than one year of experience, though almost all receive some training once on the job. Press releases are issued relatively infrequently, which implies that media engagement and message management are underdeveloped at the local level. These results suggest that health communication specialists are underutilized in LHDs and these skills should be emphasized in LHD hiring practices and in public health workforce development