8,929 research outputs found
Tool for reading psychrometric charts
Three-legged, clear plastic tool is designed so that the angles of each leg correspond with the angles of psychometric chart construction for each of the three required scales. The appropriate edges are tapered to the chart surface
Two-photon interference using background-free quantum frequency conversion of single photons from a semiconductor quantum dot
We show that quantum frequency conversion (QFC) can overcome the spectral
distinguishability common to inhomogeneously broadened solid-state quantum
emitters. QFC is implemented by combining single photons from an InAs quantum
dot (QD) at 980 nm with a 1550 nm pump laser in a periodically-poled lithium
niobate (PPLN) waveguide to generate photons at 600 nm with a
signal-to-background ratio exceeding 100:1. Photon correlation and two-photon
interference measurements confirm that both the single photon character and
wavepacket interference of individual QD states are preserved during frequency
conversion. Finally, we convert two spectrally separate QD transitions to the
same wavelength in a single PPLN waveguide and show that the resulting field
exhibits non-classical two-photon interference.Comment: Supercedes arXiv:1205.221
Relative impacts of morphological alteration to shorelines and eutrophication on littoral macroinvertebrates in Mediterranean lakes
Development of effective methods for assessing the ecological status of lakes based on littoral benthic fauna has been hampered by the lack of quantitative data on the relative impacts of key pressures on the
benthic community. We used variance partitioning at 126 sites belonging to 14 natural Mediterranean lakes to analyze the pure and shared effects of eutrophication, morphological alterations, microhabitat type, lake morphometry and geographic position on the littoral macroinvertebrate community. The spatial arrangement of the sampling sites was responsible for 9.1% of the total variance in littoral benthic community composition, lake morphometry accounted for 4.3% of variation, and microhabitat type accounted for 3.9%. Communities appeared to be affected primarily by morphological alterations to lake shorelines, and their impact was 2.5 times as important as that of eutrophication. The structure of littoral benthic communities was governed by processes acting at several spatial scales from region to lake scale. Thus, several pressures and the various spatial scales at which these act should be taken into account when implementing methods of assessing lake ecological condition based on littoral benthic invertebrates. Region-specific methods for subalpine and volcanic lakes might enhance the validity of assessment of results of morphological alterations and improve management of those water resources
Electrophoretic karyotype variation among pathotypes of Fusarium oxysporum f.sp. dianthi
Karyotype analysis by pulsed-field gel electrophoresis was applied to characterize isolates of Fusarium oxysporum f.sp. dianthi, the causal agent of Fusarium wilt on carnation. Eleven distinct chromosomal DNA patterns were detected among 38 pathogenic isolates, and the total genome size was estimated to range from 23·7 to 36·4 Mb. Except for isolates belonging to pathotypes 2 and 4, all members of the same pathotype shared overlapping electrophoretic karyotypes. Karyotypes of isolates assigned to pathotypes 1 and 8 showed a high degree of similarity, in accordance with VCG and RFLP analysis. The same electrophoretic karyotype was also shared by members of pathotypes 2 and 5, thus confirming results obtained by both VCG and RFLP grouping, A single representative of pathotype 6, previously confined to the same VCG and RFLP group as pathotypes 2 and 5, had a slightly different chromosomal pattern. Isolates assigned to pathotype 4 showed four related karyotypes which partially differed in both the number and size of chromosomal bands. However, all strains assigned to this pathotype shared a basic profile of nine chromosomal bands, while two low-molecular-weight bands were present or absent. The findings are discussed with regard both to the suitability of race distinction in the case of the special form dianthi of F. oxysporum and to the use of karyotype analysis by PFGE as a tool for the study of the population genetics of this fungu
Determination of the magnetization profile of Co/Mg periodic multilayers by magneto-optic Kerr effect and X-ray magnetic resonant reflectivity
The resonant magnetic reflectivity of Co/Mg multilayers around the Co L2,3
absorption edge is simulated then measured on a specifically designed sample.
The dichroic signal is obtained when making the difference between the two
reflectivities measured with the magnetic field applied in two opposite
directions parallel to the sample surface. The simulations show that the
existence of magnetic dead layers at the interfaces between the Co and Mg
layers leads to an important increase of the dichroic signal measured in the
vicinity of the third Bragg peak that otherwise should be negligible. The
measurements are in agreement with the model introducing 0.25 nm thick dead
layers. This is attributed to the Co atoms in contact with the Mg layers and
thus we conclude that the Co-Mg interfaces are abrupt from the magnetic point
of view.Comment: 8 page
Weighing the Milky Way
We describe an experiment to measure the mass of the Milky Way galaxy. The
experiment is based on calculated light travel times along orthogonal
directions in the Schwarzschild metric of the Galactic center. We show that the
difference is proportional to the Galactic mass. We apply the result to light
travel times in a 10cm Michelson type interferometer located on Earth. The mass
of the Galactic center is shown to contribute 10^-6 to the flat space component
of the metric. An experiment is proposed to measure the effect.Comment: 10 pages, 1 figur
Epidemiology and Impact of Abdominal Oblique Injuries in Major and Minor League Baseball.
BACKGROUND: Oblique injuries are known to be a common cause of time out of play for professional baseball players, and prior work has suggested that injury rates may be on the rise in Major League Baseball (MLB).
PURPOSE: To better understand the current incidence of oblique injuries, determine their impact based on time out of play, and to identify common injury patterns that may guide future injury prevention programs.
STUDY DESIGN: Descriptive epidemiological study.
METHODS: Using the MLB Health and Injury Tracking System, all oblique injuries that resulted in time out of play in MLB and Minor League Baseball (MiLB) during the 2011 to 2015 seasons were identified. Player demographics such as age, position/role, and handedness were included. Injury-specific factors analyzed included the following: date of injury, timing during season, days missed, mechanism, side, treatment, and reinjury status.
RESULTS: A total of 996 oblique injuries occurred in 259 (26%) MLB and 737 (74%) MiLB players. Although the injury rate was steady in MiLB, the MLB injury rate declined (P = .037). A total of 22,064 days were missed at a mean rate of 4413 days per season and 22.2 days per injury. The majority of these occurred during batting (n = 455, 46%) or pitching (n = 348, 35%), with pitchers losing 5 days more per injury than batters (P \u3c .001). The leading side was injured in 77% of cases and took 5 days longer to recover from than trailing side injuries (P = .009). Seventy-nine (7.9%) players received either a corticosteroid or platelet-rich plasma injection, and the mean recovery time was 11 days longer compared with those who did not receive an injection (P \u3c .001).
CONCLUSION: Although the rate of abdominal oblique injuries is on the decline in MLB, this is not the case for MiLB, and these injuries continue to represent a significant source of time out of play in professional baseball. The vast majority of injuries occur on the lead side, and these injuries result in the greatest amount time out of play. The benefit of injections for the treatment of oblique injuries remains unknown
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