2,417 research outputs found
Fluctuation Probes of Quark Deconfinement
The size of the average fluctuations of net baryon number and electric charge
in a finite volume of hadronic matter differs widely between the confined and
deconfined phases. These differences may be exploited as indicators of the
formation of a quark-gluon plasma in relativistic heavy-ion collisions, because
fluctuations created in the initial state survive until freeze-out due to the
rapid expansion of the hot fireball.Comment: 4 pages RevTeX, 1 figure; submitted simultaneously with
hep-ph/0003168. Relative to v2 a typo was corrected, and the "Note added" was
expanded by a clarifying sentence. This version accepted by Physical Review
Letter
Herschel-PACS photometry of faint stars
Our aims are to determine flux densities and their photometric accuracy for a
set of seventeen stars that range in flux from intermediately bright (<2.5 Jy)
to faint (>5 mJy) in the far-infrared (FIR). We also aim to derive
signal-to-noise dependence with flux and time, and compare the results with
predictions from the Herschel exposure-time calculation tool. The PACS faint
star sample has allowed a comprehensive sensitivity assessment of the PACS
photometer. Accurate photometry allows us to establish a set of five FIR
primary standard candidates, namely alpha Ari, epsilon Lep, omega,Cap, HD41047
and 42Dra, which are 2 -- 20 times fainter than the faintest PACS fiducial
standard (gamma Dra) with absolute accuracy of <6%. For three of these primary
standard candidates, essential stellar parameters are known, meaning that a
dedicated flux model code may be run.Comment: 42 pages, 12 figure
Creativity and Information Systems in a Hypercompetitive Environment: A Literature Review
In today’s hypercompetitive environment in which markets change rapidly and competitive advantages are difficult to sustain, companies are forced to innovate and identify new business opportunities. However, innovation requires ingenuity and creativity. Product and service development depends on the creativity of employees, but harvesting and bringing novel ideas to fruition is often a chaotic process, which underscores the importance of creativity management within organizations. In this article, we review the literature on creativity in an effort to summarize state-of-the-art knowledge on how to stimulate creativity and spur innovation in modern organizations. For that purpose, we use Rhodes’ 4-Ps model (1961) distinguishing between creative environments (called press), people, products, and processes. Through a review of 110 journals on the AIS journal list, this article offers insights―based on eighty-eight articles―into how creativity can be stimulated and supported by attending to each of these components. The literature teaches us how to utilize, evaluate, and strategize about creativity in organizational settings. Managers are advised to advance creativity and ideation processes, for example by building virtual environments that strengthen collaboration and creativity across organizational boundaries. Researchers are encouraged to investigate the relationship between strategy and information systems (IS) usage in fostering creativity
Operations and Performance of the PACS Instrument 3He Sorption Cooler on board of the Herschel Space Observatory
A 3He sorption cooler produced the operational temperature of 285mK for the
bolometer arrays of the Photodetector Array Camera and Spectrometer (PACS)
instrument of the Herschel Space Observatory. This cooler provided a stable
hold time between 60 and 73h, depending on the operational conditions of the
instrument. The respective hold time could be determined by a simple functional
relation established early on in the mission and reliably applied by the
scientific mission planning for the entire mission. After exhaustion of the
liquid 3He due to the heat input by the detector arrays, the cooler was
recycled for the next operational period following a well established automatic
procedure. We give an overview of the cooler operations and performance over
the entire mission and distinguishing in-between the start conditions for the
cooler recycling and the two main modes of PACS photometer operations. As a
spin-off, the cooler recycling temperature effects on the Herschel cryostat 4He
bath were utilized as an alternative method to dedicated Direct Liquid Helium
Content Measurements in determining the lifetime of the liquid Helium coolant.Comment: 34 pages, 13 figures, accepted in Experimental Astronom
European ectoparasitoids of two classical weed biological control agents released in North America
The ceutorhynchine weevils Hadroplontus litura (F.) and Microplontus edentulus (Schultze) (Coleoptera: Curculionidae), are established in North America as biological control agents for Canada thistle, Cirsium arvense (L.) Scop., and scentless chamomile, Tripleurospermum perforatum (MĂ©rat) M. Lainz (Asteraceae), respectively. In North America, both weeds occur sympatrically and in similar habitats as another ceutorhynchine, Ceutorhynchus obstrictus (Marsham) (cabbage seedpod weevil), an important pest of canola, Brassica napus L., and Brassica rapa L. (Brassicaceae). Ceutorhynchinae weevils released to control weeds in cultivated crops may serve as alternate hosts if agents released for biological control of C. obstrictus are not specific to that species. Parasitoids associated with M. edentulus and H. litura inflict similar levels of mortality on their hosts, yet a single species was associated with the latter host, whereas 13 species attacked the former. The stem-mining M. edentulus appears to be at some risk but not the root-crown feeding H. litura, should the parasitoids Trichomalus perfectus (Walker) and Mesopolobus morys (Walker) (Hymenoptera: Pteromalidae) be introduced as biological control agents of the silique-feeding C. obstrictus. These findings suggest that feeding niche may be an important criterion for developing a nontarget species test list for host-range testing of potential biological control agent
Larval phenologies and parasitoids of two seed-feeding weevils associated with hoary cress and shepherd's purse (Brassicaceae) in Europe
In Europe, Ceutorhynchus turbatus Schultze and Ceutorhynchus typhae (Herbst) (Coleoptera: Curculionidae) feed on seeds from hoary cress and shepherd's purse (Cardaria draba (L.) Desv. and Capsella bursa-pastoris (L.) Medik.); both plants are invasive in North America. In North America, C. turbatus is a candidate for biological control of hoary cress, C. typhae is adventive, and both are sympatric with cabbage seedpod weevil (Ceutorhynchus obstrictus (Marsham)), an invasive alien pest of canola (Brassica napus L. and Brassica rapa L., Brassicaceae). We investigated host associations among C. turbatus, C. typhae, and their parasitoids in Europe. Of particular interest was host specificity of Trichomalus perfectus (Walker) and Mesopolobus morys (Walker) (Hymenoptera: Pteromalidae), candidates for biological control of C. obstrictus in North America. We found no evidence that T. perfectus attacks C. turbatus or C. typhae; however, M. morys was the most common parasitoid associated with C. turbatu
Supercurrent-phase relationship of a Nb/InAs(2DES)/Nb Josephson junction in overlapping geometry
Superconductor/normal conductor/superconductor (SNS) Josephson junctions with
highly transparent interfaces are predicted to show significant deviations from
sinusoidal supercurrent-phase relationships (CPR) at low temperatures. We
investigate experimentally the CPR of a ballistic Nb/InAs(2DES)/Nb junction in
the temperature range from 1.3 K to 9 K using a modified Rifkin-Deaver method.
The CPR is obtained from the inductance of the phase-biased junction. Transport
measurements complement the investigation. At low temperatures, substantial
deviations of the CPR from conventional tunnel-junction behavior have been
observed. A theoretical model yielding good agreement to the data is presented.Comment: RevTex4, 4 pages including 3 figure
Review of the species of Trichomalus (Chalcidoidea: Pteromalidae) associated with Ceutorhynchus (Coleoptera: Curculionidae) host species of European origin
Six species of Trichomalus Thomson were reared as parasitoids of Ceutorhynchinae hosts in Europe during surveys in 2000-2004. Trichomalus rusticus (Walker) is treated as a valid species, resurrected from synonymy under T. lucidus (Walker), and T. lyttus (Walker) is transferred from synonymy under T. lucidus and newly placed in synonymy with T. rusticus. Illustrated keys to females and males are given to differentiate the six species (T. bracteatus (Walker), T. campestris (Walker), T. gynetelus (Walker), T. lucidus, T. perfectus (Walker), and T. rusticus) except for males of T. bracteatus and T. gynetelus. A lectotype female is designated for T. rusticus. Trichomalus campestris is newly recorded as a parasitoid of Ceutorhynchus cardariae Korotyaev. Implications of the host-parasitoid associations recovered by the surveys are discussed relative to introduction of species to North America for classical biological contro
The role of subvocal rehearsal in preschool children’s prospective memory
4-year-olds had worse PM than 5-year-olds.•Children in the verbal interference condition had worse PM compared to children in the standard condition.•PM performance was correlated with verbal working memory and receptive vocabulary in the verbal interference condition only.•Children with better verbal ability were better able to cope with verbal interference to the benefit of their PM performance. The current study examined the impact of a verbal interference manipulation on 4- and 5- year olds’ prospective memory (PM). Children were randomly assigned to either complete a quiet delay activity (standard condition) or answer questions aloud during the delay activity (verbal interference condition). Children then completed a PM task followed by several individual differences measures (verbal working memory, inhibitory control, and receptive vocabulary). Four-year-olds showed worse PM than 5-year-olds, children in the verbal interference condition showed worse PM compared to the standard condition, and there was a marginal interaction between age and condition driven by poor performance of 4-year-olds in the verbal interference condition. PM performance was positively correlated with verbal working memory and receptive vocabulary (but not inhibitory control) in the verbal interference condition only suggesting that children with better verbal abilities were more able to cope with verbal interference to the benefit of their PM
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