138 research outputs found

    The Effect of Alien Predatory Ants (Hymenoptera: Formicidae) on Hawaiian Endemic Spiders (Araneae: Tetragnathidae)

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    The fauna of the Hawaiian Islands is characterized by spectacular species radiations with high levels of endemism, which is coupled with an extreme vulnerability to invasion by alien species. Of all alien invertebrate predators, ants are most notorious in their effect on native Hawaiian biota. This study examined distribution of ants in mesic and wet forests throughout the Hawaiian Islands and the extent to which they overlap the range of representatives of a lineage of endemic Hawaiian invertebrates, the genus Tetragnatha (Araneae: Tetragnathidae). Two species, Pheidole megacephala (F.) and Anoplolepis longipes (Jerdon), were implicated in the exclusion of native spiders from native and disturbed forest. One species, Solenopsis papuana Emery, showed extensive overlap in its range with that of the native spiders. However, we found a significant inverse relationship between the abundance of S. papuana in an area and the diversity of the indigenous Tetragnatha. Interactions between the spiders and the two species of ants, P. megacephala and A. longipes, were conducted in the laboratory and indicated that the spiders were very vulnerable to attack by these ants. Alien spiders appear to tolerate the presence of ants because they have either a strong exoskeleton, can appendotomize their legs, or else are capable of wrapping the ant in silk. Spiders that normally coexist with ants appear to use one or more of these methods for defense. The riparian existence of the genus Tetragnatha outside Hawaii may protect it from predation by ants. In Hawaii, where their habitat preference is no longer restricted to riparian sites, they may be extremely vulnerable to these alien predators

    Red Imported Fire Ant, a Seriously Harmful Potential Invasive Species

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    Although Solenopsis invicta is not present in Hawaii, this publication advised of the threat its possible introduction poses; its biology and potential impacts are described. The distinction between this pest and S. geminata, the tropical fire ant, which is present in Hawaii, is described

    Bait Preference by the Argentine Ant (Hymenoptera: Formicidae) In Haleakala National Park, Hawaii

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    The Argentine ant, Linepithema humile (Mayr), has proven to be a threat to native arthropod species in Haleakala National Park, Maui, HI, and is also a potential threat to the park\u27s native flora. As it continues to expand its range, an effort has been undertaken to eradicate it, or at the least, control its spread. The 1st part of this effort focused on finding a bait carrier for subsequent toxicant-based control tests. A year-long bait preference test was implemented at each of the ant\u27s 2 infestation sites in Haleakala National Park, in which 6 solid baits and 2 liquid baits were assessed for attractiveness and feasibility for large scale control. At both sites, a toxicant-free formulation of Maxforce, a protein-based granular bait made from ground silkworm, Bombyx mori (L.), pupae, and a 25% sugar water solution were the most attractive baits. Ants took more Maxforce (without toxicant) and sugar water than all other baits, including honey granules and a fish protein bait. Sugar water, however, is difficult to distribute over large natural areas. Maxforce was therefore concluded to be the best bait carrier for toxicant-based control at Haleakala National Park because of its attractiveness and its ease for large scale broadcast dispersal

    A lack of freshwater reservoir effects in human radiocarbon dates in the Eneolithic to Iron Age in the Minusinsk Basin

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    A number of recent studies have highlighted the importance of freshwater reservoir effects (FRE) when dating human remains across large parts of Eurasia, including the Eurasian steppes. Here,we address this question in the context of the Early Bronze Age (Okunevo), Late Bronze Age (Karasuk) and Late Iron Age (Tashtyk culture) of the Minusinsk Basin, Southern Siberia. The issue is important given the large number of radiocarbon dates that have been published on human remains here, which have been used both to refine the cultural historical sequence (Svyatko et al. 2009), as well as to suggest a date of ca. 1400 BC for the appearance of millet agriculture (Svyatko et al. 2013). In these studies, it was argued that there was little or no freshwater reservoir effect to take into account, despite the likely consumption of freshwater fish. Subsequent work across the steppe raised a legitimate question concerning this assumption. Here, we present the first set of paired dates on late prehistoric humans and terrestrial fauna from the Minusinsk Basin, as well as data from modern fish for the region. The results, with one exception, show no clear evidence for a reservoir effect, with the human-fauna difference averaging −31 ± 95 14C years. Yet, dating of modern fish from the Yenisei River and its tributary Karasuk River does show a variable but significant FRE. Either this effect has changed radically over time, or the contribution of fish to human diets in the Minusinsk Basin was less than previously thought

    Design and introduction of a quality of life assessment and practice support system: perspectives from palliative care settings

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    Background: Quality of life (QOL) assessment instruments, including patient-reported outcome measures (PROMs) and patient-reported experience measures (PREMs), are increasingly promoted as a means of enabling clinicians to enhance person-centered care. However, integration of these instruments into palliative care clinical practice has been inconsistent. This study focused on the design of an electronic Quality of Life and Practice Support System (QPSS) prototype and its initial use in palliative inpatient and home care settings. Our objectives were to ascertain desired features of a QPSS prototype and the experiences of clinicians, patients, and family caregivers in regard to the initial introduction of a QPSS in palliative care, interpreting them in context. Methods: We applied an integrated knowledge translation approach in two stages by engaging a total of 71 clinicians, 18 patients, and 17 family caregivers in palliative inpatient and home care settings. Data for Stage I were collected via 12 focus groups with clinicians to ascertain desirable features of a QPSS. Stage II involved 5 focus groups and 24 interviews with clinicians and 35 interviews with patients or family caregivers during initial implementation of a QPSS. The focus groups and interviews were recorded, transcribed, and analyzed using the qualitative methodology of interpretive description. Results: Desirable features focused on hardware (lightweight, durable, and easy to disinfect), software (simple, user-friendly interface, multi-linguistic, integration with e-health systems), and choice of assessment instruments that would facilitate a holistic assessment. Although patient and family caregiver participants were predominantly enthusiastic, clinicians expressed a mixture of enthusiasm, receptivity, and concern regarding the use of a QPSS. The analyses revealed important contextual considerations, including: (a) logistical, technical, and aesthetic considerations regarding the QPSS as a technology, (b) diversity in knowledge, skills, and attitudes of clinicians, patients, and family caregivers regarding the integration of electronic QOL assessments in care, and (c) the need to understand organizational context and priorities in using QOL assessment data. Conclusion: The process of designing and integrating a QPSS in palliative care for patients with life-limiting conditions and their family caregivers is complex and requires extensive consultation with clinicians, administrators, patients, and family caregivers to inform successful implementation

    Low-repetition-rate Integrated Electro-optic Frequency Comb Sources

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    We demonstrate a low-repetition-rate lithium niobate based electro-optic (EO) frequency comb operating with 3.481 GHz line spacing, by integrating a cavity-based EO comb source with traveling-wave phase-modulators on the same chip

    Magnetic field induced delocalization in hybrid electron-nuclear spin ensembles

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    We use field-cycling-assisted dynamic nuclear polarization and continuous radio-frequency (RF) driving over a broad spectral range to demonstrate magnetic-field-dependent activation of nuclear spin transport from strongly hyperfine-coupled C13 sites in diamond. We interpret our observations with the help of a theoretical framework where nuclear spin interactions are mediated by electron spins. In particular, we build on the results from a four-spin toy model to show how otherwise localized nuclear spins must thermalize as they are brought in contact with a larger ancilla spin network. Further, by probing the system response to a variable driving field amplitude, we witness stark changes in the RF-absorption spectrum, which we interpret as partly due to contributions from heterogeneous multispin sets, whose zero-quantum transitions become RF active thanks to the hybrid electron-nuclear nature of the system. These findings could prove relevant in applications to dynamic nuclear polarization, spin-based quantum information processing, and nanoscale sensing.Fil: Pagliero, Daniela. City University Of New York. The Graduate Center; Estados UnidosFil: Zangara, Pablo René. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Henshaw, Jacob. City University of New York. The City College of New York; Estados UnidosFil: Ajoy, Ashok. University of California at Berkeley; Estados UnidosFil: Acosta, Rodolfo Héctor. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Manson, Neil. Australian National University; AustraliaFil: Reimer, Jeffrey A.. University of California at Berkeley; Estados Unidos. Lawrence Berkeley National Laboratory; Estados UnidosFil: Pines, Alexander. University of California at Berkeley; Estados Unidos. Lawrence Berkeley National Laboratory; Estados UnidosFil: Meriles, Carlos A.. City University Of New York. The Graduate Center; Estados Unido

    Magnetic-field-induced delocalization in hybrid electron-nuclear spin ensembles

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    We use field-cycling-assisted dynamic nuclear polarization and continuous radio-frequency (RF) driving over a broad spectral range to demonstrate magnetic-field-dependent activation of nuclear spin transport from strongly-hyperfine-coupled 13C sites in diamond. We interpret our observations with the help of a theoretical framework where nuclear spin interactions are mediated by electron spins. In particular, we build on the results from a 4-spin toy model to show how otherwise localized nuclear spins must thermalize as they are brought in contact with a larger ancilla spin network. Further, by probing the system response to a variable driving field amplitude, we witness stark changes in the RF-absorption spectrum, which we interpret as partly due to contributions from heterogeneous multi-spin sets, whose 'zero-quantum' transitions become RF active thanks to the hybrid electron-nuclear nature of the system. These findings could prove relevant in applications to dynamic nuclear polarization, spin-based quantum information processing, and nanoscale sensing

    Spectral control of nonclassical light using an integrated thin-film lithium niobate modulator

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    Manipulating the frequency and bandwidth of nonclassical light is essential for implementing frequency-encoded/multiplexed quantum computation, communication, and networking protocols, and for bridging spectral mismatch among various quantum systems. However, quantum spectral control requires a strong nonlinearity mediated by light, microwave, or acoustics, which is challenging to realize with high efficiency, low noise, and on an integrated chip. Here, we demonstrate both frequency shifting and bandwidth compression of nonclassical light using an integrated thin-film lithium niobate (TFLN) phase modulator. We achieve record-high electro-optic frequency shearing of telecom single photons over terahertz range (±\pm 641 GHz or ±\pm 5.2 nm), enabling high visibility quantum interference between frequency-nondegenerate photon pairs. We further operate the modulator as a time lens and demonstrate over eighteen-fold (6.55 nm to 0.35 nm) bandwidth compression of single photons. Our results showcase the viability and promise of on-chip quantum spectral control for scalable photonic quantum information processing
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