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Abstract Pathogen spillover corresponds to the transmission of a pathogen or parasite from an original host species to a novel host species, preluding disease emergence. Understanding the interacting factors that lead to pathogen transmission in a zoonotic cycle could help identify novel hosts of pathogens and the patterns that lead to disease emergence. We hypothesize that ecological and biogeographic factors drive host encounters, infection susceptibility, and cross‐species spillover transmission. Using a rodent–ectoparasite system in the Neotropics, with shared ectoparasite associations as a proxy for ecological interaction between rodent species, we assessed relationships between rodents using geographic range, phylogenetic relatedness, and ectoparasite associations to determine the roles of generalist and specialist hosts in the transmission cycle of hantavirus. A total of 50 rodent species were ranked on their centrality in a network model based on ectoparasites sharing. Geographic proximity and phylogenetic relatedness were predictors for rodents to share ectoparasite species and were associated with shorter network path distance between rodents through shared ectoparasites. The rodent–ectoparasite network model successfully predicted independent data of seven known hantavirus hosts. The model predicted five novel rodent species as potential, unrecognized hantavirus hosts in South America. Findings suggest that ectoparasite data, geographic range, and phylogenetic relatedness of wildlife species could help predict novel hosts susceptible to infection and possible transmission of zoonotic pathogens. Hantavirus is a high‐consequence zoonotic pathogen with documented animal‐to‐animal, animal‐to‐human, and human‐to‐human transmission. Predictions of new rodent hosts can guide active epidemiological surveillance in specific areas and wildlife species to mitigate hantavirus spillover transmission risk from rodents to humans. This study supports the idea that ectoparasite relationships among rodents are a proxy of host species interactions and can inform transmission cycles of diverse pathogens circulating in wildlife disease systems, including wildlife viruses with epidemic potential, such as hantavirus.

Abstract Background Suicide is an alarming public health problem accounting for a considerable number of deaths each year worldwide. Many more individuals contemplate suicide. Understanding the attributes, characteristics, and exposures correlated with suicide remains an urgent and significant problem. As social networking sites have become more common, users have adopted these sites to talk about intensely personal topics, among them their thoughts about suicide. Such data has previously been evaluated by analyzing the language features of social media posts and using factors derived by domain experts to identify at-risk users. Results In this work, we automatically extract informal latent recurring topics of suicidal ideation found in social media posts. Our evaluation demonstrates that we are able to automatically reproduce many of the expertly determined risk factors for suicide. Moreover, we identify many informal latent topics related to suicide ideation such as concerns over health, work, self-image, and financial issues. Conclusions These informal topics topics can be more specific or more general. Some of our topics express meaningful ideas not contained in the risk factors and some risk factors do not have complimentary latent topics. In short, our analysis of the latent topics extracted from social media containing suicidal ideations suggests that users of these systems express ideas that are complementary to the topics defined by experts but differ in their scope, focus, and precision of language.

Pathogen spillover corresponds to the transmission of a pathogen or parasite from an original host species to a novel host species, preluding disease emergence. Understanding the interacting factors that lead to pathogen transmission in a zoonotic cycle could help identify novel hosts of pathogens and the patterns that lead to disease emergence. We hypothesize that ecological and biogeographic factors drive host encounters, infection susceptibility, and cross‐species spillover transmission. Using a rodent–ectoparasite system in the Neotropics, with shared ectoparasite associations as a proxy for ecological interaction between rodent species, we assessed relationships between rodents using geographic range, phylogenetic relatedness, and ectoparasite associations to determine the roles of generalist and specialist hosts in the transmission cycle of hantavirus. A total of 50 rodent species were ranked on their centrality in a network model based on ectoparasites sharing. Geographic proximity and phylogenetic relatedness were predictors for rodents to share ectoparasite species and were associated with shorter network path distance between rodents through shared ectoparasites. The rodent–ectoparasite network model successfully predicted independent data of seven known hantavirus hosts. The model predicted five novel rodent species as potential, unrecognized hantavirus hosts in South America. Findings suggest that ectoparasite data, geographic range, and phylogenetic relatedness of wildlife species could help predict novel hosts susceptible to infection and possible transmission of zoonotic pathogens. Hantavirus is a high‐consequence zoonotic pathogen with documented animal‐to‐animal, animal‐to‐human, and human‐to‐human transmission. Predictions of new rodent hosts can guide active epidemiological surveillance in specific areas and wildlife species to mitigate hantavirus spillover transmission risk from rodents to humans. This study supports the idea that ectoparasite relationships among rodents are a proxy of host species interactions and can inform transmission cycles of diverse pathogens circulating in wildlife disease systems, including wildlife viruses with epidemic potential, such as hantavirus. [ABSTRACT FROM AUTHOR]

To investigate the impact of including the response option of 'Possibly' in the Distress question on the Matthey Generic Mood Questionnaire (MGMQ) during antenatal emotional health screening in English-speaking women. Some distress screening questions only allow respondents to choose between 'Yes' or 'No' to the presence of distress. The MGMQ, however, allows respondents to chose between 'Yes', 'Possibly', or 'No', which may be preferable if a participant is reluctant to state she definitely feels distressed. In Study 1, women undergoing routine antenatal psychosocial screening were allocated to either completing the MGMQ Distress question with the usual three-option response format of 'Yes, Possibly, No' (N = 960), or just a 'Yes, No' response format (N = 771). The proportion of responses were compared in each group, as were the proportion then screening positive on the MGMQ's Bother question. In Study 2, women (N = 113) attending routine antenatal clinic appointments were asked about their preference between these response formats. Including 'Possibly' resulted in only a slight increase in the proportion giving a positive response to the Distress question, and then also screening positive on the Bother question. In Study 2, a substantial majority of women (80%) preferred having 'Possibly' in the response options. While the impact of including 'Possibly' is small, it allows for more women to communicate how they are feeling on the full MGMQ. Given the large majority of women preferring having 'Possibly' included, we believe that the Distress Question is enhanced by having this as a response option. [ABSTRACT FROM AUTHOR]

The gas-phase optical spectra of three silicon-terminated carbon chain radicals, SiCnH (n = 3-5), formed in a jet-cooled discharge of silane and acetylene, have been investigated by resonant two-color two-photon ionization and laser-induced fluorescence/dispersed fluorescence. Analysis of the spectra was facilitated by calculations performed using equation-of-motion coupled cluster methods. For SiC3H and SiC5H, the observed transitions are well-described as excitations from a ²Π ground state to a ²∑ state, in which vibronic coupling, likely involving a higher-lying Π state with a very large predicted ƒ-value (close to unity), is persistent. The lowest 2∑ states of both species are characterized by a rare silicon triple bond, which was identified previously [T. C. Smith, H. Y. Li, D. J. Clouthier, C. T. Kingston, and A. J. Merer, J. Chem. Phys. 112, 3662 (2000)] in the lowest ²∑ state of SiCH. Although a strong Π - Π transition is predicted for SiC4H, the observed spectrum near 505 nm more likely corresponds to excitation to a relatively dark ∑ state which is vibronically coupled to a nearby Π state. In contrast to the chains with an odd number of carbon atoms, which exhibit relatively sharp spectral features and lifetimes in the 10-100 ns range, SiC4H shows intrinsically broadened spectral features consistent with a ~100 fs lifetime, and a subsequent long-lived decay (>50 μs) which we ascribe to mixing with a nearby quartet state arising from the same electronic configuration. The spin-orbit coupling constants for both SiC3H and SiC5H radicals were determined to be approximately 64 cm-1, similar to that of SiCH (69.8 cm-1), suggesting that the unpaired electron in these species is localized on the silicon atom. Motivated by the new optical work, the rotational spectrum of linear SiC3H was detected by cavity Fourier-transform microwave spectroscopy in the 13-34 GHz range. Each rotational transition from the ²Π3/2 ground state exhibits well-resolved ∧-doubling and hyperfine structure; the derived rotational constant of B = 2.605 GHz is in excellent agreement with our calculations. [ABSTRACT FROM AUTHOR]

We report the measurement of a jet-cooled electronic spectrum of the silicon trimer. Si3 was produced in a pulsed discharge of silane in argon, and the excitation spectrum examined in the 18 000-20 800 cm-1 region. A combination of resonant two-color two-photon ionization (R2C2PI) time-of-flight mass spectroscopy, laser-induced fluorescence/dispersed fluorescence, and equation-of-motion coupled-cluster calculations have been used to establish that the observed spectrum is dominated by the 13A1″ - ã 3A2′ transition of the D3h isomer. The spectrum has an origin transition at 18 600± 4 cm-1 and a short progression in the symmetric stretch with a frequency of ∼445 cm-1, in good agreement with a predicted vertical transition energy of 2.34 eV for excitation to the 13A1″ state, which has a calculated symmetric stretching frequency of 480 cm-1. In addition, a ∼505 cm-1 ground state vibrational frequency determined from sequence bands and dispersed fluorescence is in agreement with an earlier zero-electron kinetic energy study of the lowest D3h state and with theory. A weaker, overlapping band system with a ∼360 cm-1 progression, observed in the same mass channel (m/z = 84) by R2C2PI but under different discharge conditions, is thought to be due to transitions from the (more complicated) singlet C2v ground state (1A1) state of Si3. Evidence of emission to this latter state in the triplet dispersed fluorescence spectra suggests extensive mixing in the excited triplet and singlet manifolds. Prospects for further spectroscopic characterization of the singlet system and direct measurement of the energy separation between the lowest singlet and triplet states are discussed. [ABSTRACT FROM AUTHOR]

A high-resolution single vibronic level emission study from the à 2Π3/2 state of the HC4S radical is reported. Ground state density functional theory frequencies have been used to assign ground state vibronic levels involving three stretching modes ν2, ν3, and ν5 in the region of 0–3250 cm-1, while the frequency of ν4 remains speculative. Tentative assignments are given for the complicated structures arising from Renner-Teller and spin-orbit interactions within the bending energy levels. From analysis of the dispersed emission spectra, Fermi resonances involving pairs of bands have been identified in the à 2Π3/2←X 2Π3/2 laser induced fluorescence spectrum. [ABSTRACT FROM AUTHOR]