139 research outputs found
Taxon-specific multiplex-PCR for quick, easy, and accurate identification of encyrtid and aphelinid parasitoid species attacking soft scale insects in California citrus groves
Citricola scale, Coccus pseudomagnoliarum Kuwana (Hemiptera: Coccidae), is a serious pest of citrus in California's San Joaquin Valley, but not in southern California where a complex of Metaphycus spp. Mercet (Hymenoptera: Encyrtidae) suppress it. This has created interest in using these (and other Metaphycus) species for biological control in the San Joaquin Valley. A critical step in assessing an organism's potential for biological control is the ability to accurately identify it. For Metaphycus spp., this currently requires slide mounted adult specimens and expert taxonomic knowledge. We present a simple, quick and accurate method to identify any life stage of the ten major parasitoids of soft scales in California citrus, based on amplification of ribosomal DNA, using the polymerase chain reaction (PCR). Three multiplex-PCR protocols amplify products of taxon-specific sizes, allowing direct diagnosis of taxa accommodated by the PCR, and reducing identification time to a fraction of that of existing methods
Divergent Routing of Positive and Negative Information from the Amygdala during Memory Retrieval
Although the basolateral amygdala (BLA) is known to play a critical role in the formation of memories of both positive and negative valence, the coding and routing of valence-related information is poorly understood. Here, we recorded BLA neurons during the retrieval of associative memories and used optogenetic-mediated phototagging to identify populations of neurons that synapse in the nucleus accumbens (NAc), the central amygdala (CeA), or ventral hippocampus (vHPC). We found that despite heterogeneous neural responses within each population, the proportions of BLA-NAc neurons excited by reward predictive cues and of BLA-CeA neurons excited by aversion predictive cues were higher than within the entire BLA. Although the BLA-vHPC projection is known to drive behaviors of innate negative valence, these neurons did not preferentially code for learned negative valence. Together, these findings suggest that valence encoding in the BLA is at least partially mediated via divergent activity of anatomically defined neural populations.National Institute of Mental Health (U.S.) (Grant R01-MH102441-01)National Institutes of Health (U.S.) (Grant DP2-DK-102256-01
Evaluaci\uf3n de un detergente en base a benceno sulfonato de sodio para el control de la mosquita blanca Aleurothrixus floccosus (Maskell) (Hemiptera: Aleyrodidae) y de la ara\uf1ita roja Panonychus citri (McGregor) (Acarina: Tetranychidae) en naranjos y mandarinos
The woolly whitefly Aleurothrixus floccosus (Maskell), and the red
citrus red mite Panonychus citri (McGregor), are considered serious
citrus pests which may cause economic damage, and the use of non
selective insecticides increases the problem due to the effect on the
natural enemies. To evaluate the use of detergent based on sodium
benzene sulfonate on the reduction of whiteflies, mites and natural
enemies, experiments were performed in two citrus orchards. The first
field trial was carried out on in a mandarin orchard ( Citrus
reticulata Blanco) infested by the woolly whitefly at El Palqui (IV
Region, Chile). The experiment consisted of the evaluation of two
applications of detergent (February 10th and March 3rd, 1998), compared
with an untreated control. The results showed significant differences
in A. floccosus populations between sprayed and untreated trees from
May to July. The mean of parasitized nymphs between March and August
was 89.6% in treated trees and 57.1% in untreated trees. The proportion
of fruits at harvest with sooty mould was lower on untreated trees
compared with the control, 2.3% and 45.5%, respectively. The second
field trial was carried out on an orange orchard trees ( Citrus
sinensis (L.) Osbeck), infested by the citrus red miteat Hijuelas (V
Region) and included the following applications detergent,
chinometionate, mineral oil and water. Chinometionate produced an
effective control of the phytophagous mites populations and an almost
total elimination of natural enemies such as phytoseiids and the
coccinellid Stethorus histrio Chazeau. The application of detergent
and mineral oil showed less control compared to the acaricide and less
impact on populations of natural enemies.La mosquita blanca Aleurothrixus floccosus (Maskell) y la
ara\uf1ita roja Panonychus citri (McGregor) son consideradas plagas
que causan da\uf1os econ\uf3micos a los c\uedtricos, y el uso de
insecticidas no selectivos aumenta el problema por su efecto sobre los
enemigos naturales. Para evaluar el uso del detergente en base a
benceno sulfonato de sodio en la reducci\uf3n de mosquitas blancas,
ara\uf1itas y sus enemigos naturales se desarrollaron experimentos en
dos huertos de c\uedtricos. El primer ensayo fue realizado en un
huerto de mandarinos ( Citrus reticulata Blanco) infestado con
mosquitas blancas en El Palqui (IV Regi\uf3n). El experimento
consisti\uf3 en la evaluaci\uf3n de dos aplicaciones del detergente
(10 de febrero y 3 de marzo de 1998), comparado con un control sin
aplicaci\uf3n. Los resultados mostraron diferencias significativas en
la presencia de A. floccosus entre \ue1rboles asperjados y no
asperjados, desde mayo a julio. Entremarzo y agosto de 1998 el promedio
de ninfas parasitadas en los \ue1rboles tratados fue de 89,6 y de
57,1% en las plantas sin lavar. La proporci\uf3n de frutos manchados
con fumagina en la cosecha fue menor en los \ue1rboles asperjados
comparados con el control, 2,3 y 45,5%, respectivamente. El segundo
ensayo fue realizado en un huerto de naranjos ( Citrus sinensis (L.)
Osbeck) infestado con ara\uf1ita roja de los c\uedtricos en
Hijuelas (V Regi\uf3n) y consider\uf3 la aplicaci\uf3n de:
detergente, chinometionate, aceite mineral y agua. Chinometionate
produjo un efectivo control de las ara\uf1itas fit\uf3fagas y una
eliminaci\uf3n casi total de sus enemigos naturales representados por
fitoseidos y el coccin\ue9lido Stethorus histrio Chazeau. La
aplicaci\uf3n del detergente y el aceite mineral mostraron una
actividad inferior al acaricida y un impacto menor sobre las
poblaciones de enemigos naturales
On the Role of Attention in Binocular Rivalry: Electrophysiological Evidence
During binocular rivalry visual consciousness fluctuates between two dissimilar monocular images. We investigated the role of attention in this phenomenon by comparing event-related potentials (ERPs) when binocular-rivalry stimuli were attended with when they were unattended. Stimuli were dichoptic, orthogonal gratings that yielded binocular rivalry and dioptic, identically oriented gratings that yielded binocular fusion. Events were all possible orthogonal changes in orientation of one or both gratings. We had two attention conditions: In the attend-to-grating condition, participants had to report changes in perceived orientation, focussing their attention on the gratings. In the attend-to-fixation condition participants had to report changes in a central fixation target, taking attention away from the gratings. We found, surprisingly, that attending to rival gratings yielded a smaller ERP component (the N1, from 160–210 ms) than attending to the fixation target. To explain this paradoxical effect of attention, we propose that rivalry occurs in the attend-to-fixation condition (we found an ERP signature of rivalry in the form of a sustained negativity from 210–300 ms) but that the mechanism processing the stimulus changes is more adapted in the attend-to-grating condition than in the attend-to-fixation condition. This is consistent with the theory that adaptation gives rise to changes of visual consciousness during binocular rivalry
An electrophysiological study of the object-based correspondence effect: Is the effect triggered by an intended grasping action?
EEG Correlates of Attentional Load during Multiple Object Tracking
While human subjects tracked a subset of ten identical, randomly-moving objects, event-related potentials (ERPs) were evoked at parieto-occipital sites by task-irrelevant flashes that were superimposed on either tracked (Target) or non-tracked (Distractor) objects. With ERPs as markers of attention, we investigated how allocation of attention varied with tracking load, that is, with the number of objects that were tracked. Flashes on Target discs elicited stronger ERPs than did flashes on Distractor discs; ERP amplitude (0–250 ms) decreased monotonically as load increased from two to three to four (of ten) discs. Amplitude decreased more rapidly for Target discs than Distractor discs. As a result, with increasing tracking loads, the difference between ERPs to Targets and Distractors diminished. This change in ERP amplitudes with load accords well with behavioral performance, suggesting that successful tracking depends upon the relationship between the neural signals associated with attended and non-attended objects
Hemicraniectomy: A New Model for Human Electrophysiology with High Spatio-temporal Resolution
Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis
BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London
Orbit and Dynamical Mass of the Late-T Dwarf Gl 758 B
Gl 758 B is a late-T dwarf orbiting a metal-rich Sun-like star at a projected
separation of 1.6" (25 AU). We present four epochs of
astrometry of this system with NIRC2 at Keck Observatory spanning 2010 to 2017
together with 630 radial velocities (RVs) of the host star acquired over the
past two decades from McDonald Observatory, Keck Observatory, and the Automated
Planet Finder at Lick Observatory. The RVs reveal that Gl 758 is accelerating
with an evolving rate that varies between 2-5 m s yr, consistent
with the expected influence of the imaged companion Gl 758 B. A joint fit of
the RVs and astrometry yields a dynamical mass of 42
M for the companion with a robust lower limit of 30.5
M at the 4- level. Gl 758 B is on an eccentric orbit
( = 0.26-0.67 at 95% confidence) with a semimajor axis of =
AU and an orbital period of = yr,
which takes it within 9 AU from its host star at periastron passage.
Substellar evolutionary models generally underpredict the mass of Gl 758 B for
nominal ages of 1-6 Gyr that have previously been adopted for the host star.
This discrepancy can be reconciled if the system is older---which is consistent
with activity indicators and recent isochrone fitting of the host star---or
alternatively if the models are systematically overluminous by 0.1-0.2
dex. Gl 758 B is currently the lowest-mass directly imaged companion inducing a
measured acceleration on its host star. In the future, bridging RVs and
high-contrast imaging with the next generation of extremely large telescopes
and space-based facilities will open the door to the first dynamical mass
measurements of imaged exoplanets.Comment: AJ, accepte
Taxon-specific multiplex-PCR for quick, easy, and accurate identification of encyrtid and aphelinid parasitoid species attacking soft scale insects in California citrus groves
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