1,889 research outputs found
Dispersive Optical Interface Based on Nanofiber-Trapped Atoms
We dispersively interface an ensemble of one thousand atoms trapped in the
evanescent field surrounding a tapered optical nanofiber. This method relies on
the azimuthally-asymmetric coupling of the ensemble with the evanescent field
of an off-resonant probe beam, transmitted through the nanofiber. The resulting
birefringence and dispersion are significant; we observe a phase shift per atom
of \,1\,mrad at a detuning of six times the natural linewidth,
corresponding to an effective resonant optical density per atom of 0.027.
Moreover, we utilize this strong dispersion to non-destructively determine the
number of atoms.Comment: 4 pages, 4 figure
The facilitatory effect of duloxetine combined with pelvic floor muscle training on the excitability of urethral sphincter motor neurons
INTRODUCTION AND HYPOTHESIS: Aim of this study was to investigate the excitability of sphincter motor neurons under the influence of pelvic floor muscle training (PFMT) and duloxetine. Due to their mechanisms of action, there might be a synergistic effect of duloxetine and PFMT in regard to the facilitation of spinal reflexes controlling urethral sphincter contractions and hence continence. METHODS: In ten healthy female subjects, clitoral electric stimulation (CES) and transcranial magnetic stimulation (TMS) were used to determine individual motor thresholds for external urethral sphincter (EUS) contractions before and after PFMT, duloxetine, and PFMT + duloxetine. RESULTS: PFMT and duloxetine alone significantly decreased the motor thresholds for EUS contractions during CES and TMS. However, the combined treatment reduced the motor threshold for EUS contractions significantly stronger compared to PFMT or duloxetine alone. CONCLUSIONS: The results are suggestive for a synergistic facilitatory effect of PFMT and duloxetine on sphincter motor neuron activation
Private Landowners’ Willingness to Enroll Their Properties in a Public Hunting Access Program in Northeast Missouri
State wildlife agencies have successfully used public hunting access fees to increase hunting opportunity and to provide a financial incentive to private landowners for maintaining habitat. Typical payments per hectare (ac) include 1.25) on average in Kansas, 3.71(1.50) for pheasant hunting in Colorado, 12.36 (5) in North Dakota for pheasant hunting, and 1.80) on average in South Dakota. We studied the USDA Conservation Reserve Program (CRP) in 2004 in Adair, Knox, Macon, Monroe, Ralls, Randolph, Schuyler, and Scotland counties in northeast Missouri as part of a quail and songbird habitat restoration initiative. CRP is prominent in these counties with 83,040 ha (205,197 ac) enrolled. We conducted a mail-back survey of all CRP contract holders, totaling 3,283 landowners to study their willingness to enroll their properties in a hypothetical public- access hunting program. The survey was designed to provide information about landowner demographics, attitudes toward wildlife and hunting, and knowledge of wildlife habitat management aspects of the CRP. We used the Kansas Department of Wildlife and Parks Walk-In Hunting Access Program as an example for questions related to the concept of public-access hunting, and presented landowners with hypothetical annual lease payments for enrolling, using a discrete-choice modeling framework. Survey response rate was relatively high at 59.5%. The average respondent had 34.6 ha (85.5 ac) enrolled in CRP, and field size averaged 6.47 ha (16.0 ac), ranging from 0.04 to 84.9 ha (0.1–209.7 ac). Wildlife as a product of the CRP was ‘very’ or ‘somewhat important’ to 89% of respondents and, among a list of wildlife species and native plants, northern bobwhite (Colinus virginianus) was most popular with 80% of respondents checking ‘very’ or ‘somewhat important’ on the survey. The corresponding values were 53–66% for wild turkey (Meleagris gallopavo), deer, rabbit, pheasant, and songbirds. We asked if landowners would enroll any of their CRP land in a public-access hunting program (PAHP). We used 8 different versions of the survey, each with a different ‘offer’ level in the question to evaluate the potential costs of a PAHP program. The structure of the survey specified whether landowners would accept payment of 1, 3, 5, 10, or 0, 91.9% chose ‘no’, and 8.1% chose ‘don’t know’; respective values (1-1.7%, 91.3%, and 6.9%; 3-4.0%, 84.9%, and 11.2%; 5- 4.7%, 83.4%, and 11.9%; 10-8.4%, 77.0%, and 14.7%; and 2/ac (10,500. About 1,012 ha (2,500 ac) would be designated for quail hunting of this hypothetical PAHP area, based on respondents’ answers to what type of hunting they would allow. We estimate that 5,261 ha (13,000 ac) would be enrolled with 2,489 ha (6,150 ac) open for quail hunting at an annual cost of about 7/ac ($17.30/ha). There is potential to improve the feasibility of CRP lands for bobwhite hunting in northeast Missouri by adding a public-access hunting incentive, but managers will be challenged to use this approach successfully. Landowners’ inclination to allow access for deer hunting, but not for quail hunting, reduces an agency’s justification for using quail hunting access as an approach to improve conservation of bobwhites, in addition to the relatively high cost
Poynting's theorem for planes waves at an interface: a scattering matrix approach
We apply the Poynting theorem to the scattering of monochromatic
electromagnetic planes waves with normal incidence to the interface of two
different media. We write this energy conservation theorem to introduce a
natural definition of the scattering matrix S. For the dielectric-dielectric
interface the balance equation lead us to the energy flux conservation which
express one of the properties of S: it is a unitary matrix. For the
dielectric-conductor interface the scattering matrix is no longer unitary due
to the presence of losses at the conductor. However, the dissipative term
appearing in the Poynting theorem can be interpreted as a single absorbing mode
at the conductor such that a whole S, satisfying flux conservation and
containing this absorbing mode, can be defined. This is a simplest version of a
model introduced in the current literature to describe losses in more complex
systems.Comment: 5 pages, 3 figures, submitted to Am. J. Phy
Implications of Pseudospin Symmetry on Relativistic Magnetic Properties and Gamow - Teller Transitions in Nuclei
Recently it has been shown that pseudospin symmetry has its origins in a
relativistic symmetry of the Dirac Hamiltonian. Using this symmetry we relate
single - nucleon relativistic magnetic moments of states in a pseudospin
doublet to the relativistic magnetic dipole transitions between the states in
the doublet, and we relate single - nucleon relativistic Gamow - Teller
transitions within states in the doublet. We apply these relationships to the
Gamow - Teller transitions from to its mirror nucleus .Comment: 17 pages, 2 figures, to be published in PRC. Slightly revised text
with one reference adde
Extreme summers impact cropland and grassland soil microbiomes
The increasing frequency of extreme weather events highlights the need to understand how soil microbiomes respond to such disturbances. Here, metagenomics was used to investigate the effects of future climate scenarios (+0.6 °C warming and altered precipitation) on soil microbiomes during the summers of 2014-2019. Unexpectedly, Central Europe experienced extreme heatwaves and droughts during 2018-2019, causing significant impacts on the structure, assembly, and function of soil microbiomes. Specifically, the relative abundance of Actinobacteria (bacteria), Eurotiales (fungi), and Vilmaviridae (viruses) was significantly increased in both cropland and grassland. The contribution of homogeneous selection to bacterial community assembly increased significantly from 40.0% in normal summers to 51.9% in extreme summers. Moreover, genes associated with microbial antioxidant (Ni-SOD), cell wall biosynthesis (glmSMU, murABCDEF), heat shock proteins (GroES/GroEL, Hsp40), and sporulation (spoIID, spoVK) were identified as potential contributors to drought-enriched taxa, and their expressions were confirmed by metatranscriptomics in 2022. The impact of extreme summers was further evident in the taxonomic profiles of 721 recovered metagenome-assembled genomes (MAGs). Annotation of contigs and MAGs suggested that Actinobacteria may have a competitive advantage in extreme summers due to the biosynthesis of geosmin and 2-methylisoborneol. Future climate scenarios caused a similar pattern of changes in microbial communities as extreme summers, but to a much lesser extent. Soil microbiomes in grassland showed greater resilience to climate change than those in cropland. Overall, this study provides a comprehensive framework for understanding the response of soil microbiomes to extreme summers
How to be causal: time, spacetime, and spectra
I explain a simple definition of causality in widespread use, and indicate
how it links to the Kramers Kronig relations. The specification of causality in
terms of temporal differential eqations then shows us the way to write down
dynamical models so that their causal nature /in the sense used here/ should be
obvious to all. To extend existing treatments of causality that work only in
the frequency domain, I derive a reformulation of the long-standing Kramers
Kronig relations applicable not only to just temporal causality, but also to
spacetime "light-cone" causality based on signals carried by waves. I also
apply this causal reasoning to Maxwell's equations, which is an instructive
example since their casual properties are sometimes debated.Comment: v4 - add Appdx A, "discrete" picture (not in EJP); v5 - add Appdx B,
cause classification/frames (not in EJP); v7 - unusual model case; v8 add
reference
Rowing Against the Tide: Getting Landowners to Manage Habitat for Their Favorite Wildlife Species, Bobwhites
A primary cause of the decline of northern bobwhite (Colinus virginianus) is that landowners often lack adequate motivation for the arduous task of creating and managing habitat. We gained insight into some of these motivations through survey questionnaires and focus groups in Missouri, and report findings from 3 studies containing 3,057 survey responses during 2004–2007. One of the surveys targeted Conservation Reserve Program (CRP) lands (‘CRP survey’), another lands with potential for bobwhite restoration (‘bobwhite survey’), and the third focused on grassland bird restoration. Landowners in each survey identified bobwhites as the most popular (.80% of respondents chose ‘somewhat’ or ‘very’ ‘important’ to have bobwhites ‘on my land’) natural resource among a list that included deer, turkeys, prairie-chickens, native plants, grassland birds, rabbits, hawks/owls, etc. Bobwhites were highly valued by landowners, but other answers in these surveys revealed many obstacles to habitat management including economics, time, knowledge, skill, and equipment. For example, only 39% of respondents in the bobwhite survey were interested in joining a habitat restoration cooperative, and ,50% of respondents in all surveys were willing to adopt quail-friendly habitat management (prescribed fire, disking, herbicides, moderate grazing, native vegetation, presence of weeds, etc.). Bobwhite restoration programs, because of the gap between landowners’ fondness for quail, but being less willing to take action, must include a comprehensive approach, ranging from local community involvement by agency biologists and non-government organizations to resource-use policy in Washington, D.C
Electromagnetically induced transparency in cold 85Rb atoms trapped in the ground hyperfine F = 2 state
We report electromagnetically induced transparency (EIT) in cold 85Rb atoms,
trapped in the lower hyperfine level F = 2, of the ground state 5
(Tiwari V B \textit{et al} 2008 {\it Phys. Rev.} A {\bf 78} 063421). Two steady
state -type systems of hyperfine energy levels are investigated using
probe transitions into the levels F = 2 and F = 3 of the
excited state 5 in the presence of coupling transitions F = 3
F = 2 and F = 3 F = 3, respectively. The
effects of uncoupled magnetic sublevel transitions and coupling field's Rabi
frequency on the EIT signal from these systems are studied using a simple
theoretical model.Comment: 12 pages, 7 figure
- …