cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Chaos at the rim of black hole and fuzzball shadows
Creators: name: Bianchi, Massimo
name: Grillo, Alfredo
name: Morales, Jose Francisco
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We study the scattering of massless probes in the vicinity of the {\it photon-sphere} of asymptotically AdS black holes and horizon-free microstate geometries (fuzzballs). We find that these exhibit a chaotic behaviour characterised by exponentially large deviations of nearby trajectories. We compute the Lyapunov exponent $λ$ governing the exponential growth in $d$ dimensions and show that it is bounded from above by $λ_b = \sqrt{d{-}3}/2b_{\rm min}$ where $b_{\rm min}$ is the minimal impact parameter under which a massless particle is swallowed by the black hole or gets trapped in the fuzzball for a very long time. Moreover we observe that $λ$ is typically below the advocated bound on chaos $λ_H=2πκ_B T/\hbar$, that in turn characterises the radial fall into the horizon, but the bound is violated in a narrow window near extremality, where the photon-sphere coalesces with the horizon. Finally, we find that fuzzballs are characterised by Lyapunov exponents smaller than those of the corresponding BH's suggesting the possibility of discriminating the existence of micro-structures at horizon scales via the detection of ring-down modes with time scales $λ^{-1}$ longer than those expected for a BH of the given mass and spin.
description: 26 pages, 9 figures
Estimating Farm Labor Elasticities To Analyze The Effects Of Immigration Reform
Creators: name: Duffield, James A.
name: Duffield, James A.
Publisher: name: Unknown
Year: 1990
Subjects: subject: Demand and Price Analysis
subject: Labor and Human Capital
subject: Immigration reform
subject: farm labor
subject: supply and demand elasticities

description: A simultaneous equation model was utilized to help measure the impact of the Immigration Reform and Control Act (IRCA) of 1986 on the U.S. farm labor market. Data from 1948 to 1988 were used in fitting the model to estimate the responsiveness of the farm labor market to changes in economic factors such as farm prices, wages, income, and farm size. Farm labor supply and demand elasticities were derived from two-stage least squares estimates. Results found an elastic (-1.44) relationship between the demand for hired labor and changes in the real wage rate. This means a 10-percent increase in the real wage results in a 14.4-percent decline in the number of hired workers demanded. If the labor supply is restricted by the IRCA, the real wage rate is not expected to rise significantly because farm employers may switch to labor-saving technology or move to less labor-intensive crops to avoid paying higher wages. Furthermore, major labor shortages are not expected in the near future because it will take time for farmworkers, particularly aliens legalized under the program, to leave agriculture to take advantage of opportunities in the nonfarm sector.
Trappole di anidride carbonica sulla Luna
Creators: Maura Sandri
Publisher: name: Media Inaf
Year: 2021

Dopo decenni di incertezza, è stata confermata l'esistenza di trappole fredde di CO2 sulla Luna che potrebbero contenere anidride carbonica allo stato solido. La scoperta avrà probabilmente una grande influenza nella definizione delle future missioni lunari e potrebbe avere ripercussioni anche sulla presenza umana sul nostro satellite. Tutti i dettagli su Agu Geophysical Research Letters
Explaining support for a sovereign Quebec: A collective action frames approach
Creators: name: Piroth, Scott Randall
Publisher: name: ProQuest
Year: 2023
Subjects: classificationCode: 44
subject: Human society
classificationCode: 4408
subject: Political science
subject: FOS: Political science

description: This dissertation uses the concept of collective action frames to answer the question of why individuals support or oppose nationalist movements. Specifically, I examine the question of why some Quebecers supported a sovereign Quebec while other Quebecers preferred that Quebec remain part of Canada during the period from 1980 to 1995. My approach to collective action frames emphasizes the central position that values occupy in an individual's identity. Recognizing that people who belong to the same ethnic group will not necessarily have the same values helps to explain why nationalist movements often achieve only partial success in mobilizing members of an ethnic group to support nationalist goals. Using survey data, this dissertation explores the values, the perceptions of injustice, and the perceptions of agency of individual Quebecers and considers how these values and perceptions relate to support for sovereignty. Those Quebecers with more secular, more morally permissive, and more individualistic values tend to support sovereignty, and I argue that such Quebecers often view sovereignty as an opportunity for changing the status quo and creating a better society. Moreover, nationalism fulfills an important function that was largely filled by religion in the past---providing collective status for the group. In addition, this dissertation examines how both supporters and opponents of sovereignty have framed this issue in political discourse. I contend that the movement for sovereignty was remarkably successful in framing the debate in favorable terms during the period from 1980 to 1995. The issues of sovereignty and the constitution dominated Quebec's political debate. Most francophone Quebecers have embraced a Quebec-centered identity, and believe that Quebec should have special powers to protect its French culture and recognition as a distinct society in Canada's Constitution. Therefore, Canada's inability or unwillingness to provide Quebec with such powers and recognition is perceived as an injustice. Finally, most Quebecers seem to view sovereignty as a realistic option for Quebec.
Relationship between streambed mobility and invertibrate abundance in mountain streams
Creators: name: Green, Kevin
Publisher: name: University Corporation For Atmospheric Research (UCAR)
Year: 2000

I studied the relationship between streambed mobility and invertebrate abundance in mountain streams. I collected invertebrates and I measured different variables on the streambed. I calculated the difference between critical shear stress and ambient shear stress. This difference is termed sub-critical shear stress, and I compared the sub-critical shear stress with invertebrate abundance. I hypothesized that sub-critical shear stress influences invertebrate habitat. I found that there was no significant relationship between sub-critical shear stress and invertebrate abundance. I also found that there was a significant relationship between velocity and invertebrate density, indicating that velocity has an effect independent of streambed mobility.
Pilastro di luce come una spada laser sull’Etna
Creators: Marco Malaspina
Publisher: name: Media Inaf
Year: 2021

Un fenomeno ottico atmosferico molto raro, immortalato lo scorso giugno al di sopra del vulcano siciliano dal fotografo di Ragusa Giancarlo Tinè, è stato scelto dalla Nasa come Apod – immagine astronomica del giorno – del 15 novembre. A produrlo, la luce del magma incandescente riflessa dai cristalli di ghiaccio al di sopra dell’Etna
Edge States from Defects on the Noncommutative Plane
Creators: name: Pinzul, A.
name: Stern, A.
Publisher: name: arXiv
Year: 2003
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We illustrate how boundary states are recovered when going from a noncommutative manifold to a commutative one with a boundary. Our example is the noncommutative plane with a defect, whose commutative limit was found to be a punctured plane - so here the boundary is one point. Defects were introduced by removing states from the standard harmonic oscillator Hilbert space. For Chern-Simons theory, the defect acts as a source, which was found to be associated with a nonlinear deformation of the $w_\infty$ algebra. The undeformed $w_\infty$ algebra is recovered in the commutative limit, and here we show that its spatial support is in a tiny region near the puncture.
description: 9 pages; Talk presented by at the conference ``Space-time and Fundamental Interactions: Quantum Aspects'' in honor of A.P. Balachandran's 65th birthday, Vietri sul Mare, Salerno, Italy 26th-31st May, 2003
Distinguishing between local production and stratospheric origin of ozone using computer models
Creators: name: Greene, Jamila
name: Madronich, Sasha
Publisher: name: University Corporation For Atmospheric Research (UCAR)
Year: 2000

Previous studies have attempted to use computer models to differentiate stratospheric and tropospheric sources of ozone in order to quantify the contribution of ozone flux from the stratosphere to the mixing ratios of ozone in the troposphere. However, these studies usually do not include all of the cyclic chemical mechanisms involved in ozone production and destruction. Therefore, three simple models were developed that considered the effects of variable fluxes of stratospheric ozone and variable emissions of nitrogen oxides and hydrocarbons on tropospheric ozone.
Comparison of quantum mechanical and classical trajectory calculations of cross sections for ion-atom impact ionization of negative - and positive -ions for heavy ion fusion applications
Creators: name: Kaganovich, Igor D.
name: Startsev, Edward A.
name: Davidson, Ronald C.
Publisher: name: arXiv
Year: 2003
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: Accelerator Physics (physics.acc-ph)
subject: FOS: Physical sciences

description: Stripping cross sections in nitrogen have been calculated using the classical trajectory approximation and the Born approximation of quantum mechanics for the outer shell electrons of 3.2GeV I$^{-}$ and Cs$^{+}$ ions. A large difference in cross section, up to a factor of six, calculated in quantum mechanics and classical mechanics, has been obtained. Because at such high velocities the Born approximation is well validated, the classical trajectory approach fails to correctly predict the stripping cross sections at high energies for electron orbitals with low ionization potential.
description: submitted to Phys. Rev. A
Per tutto l’oro dell’universo
Creators: Maura Sandri
Publisher: name: Media Inaf
Year: 2021

Un nuovo studio basato su simulazioni ha dimostrato che la sintesi di elementi pesanti è tipica di alcuni buchi neri circondati da dischi di accrescimento la cui massa è di circa 0.01-0.1 masse solari. Le fusioni di stelle di neutroni che producono dischi di accrescimento con queste masse potrebbero pertanto essere il luogo di origine di una grande frazione degli elementi pesanti, come l’oro. Tutti i dettagli su Mnras
Moving beyond enrollment numbers: An in- depth look at gender inequality in schools in rural Nepal
Creators: name: Rothchild, Jennifer Renae
Publisher: name: ProQuest
Year: 2023
Subjects: classificationCode: 39
subject: Education
classificationCode: 3902
subject: Education policy, sociology and philosophy

description: This dissertation examines the complexities of gender inequality within schools in Jiri, Nepal. While it has been argued in the literature that equal numbers of girls and boys in schools will remedy many social and economic problems, much of the research and development efforts regarding girls and schools fails to consider access to and participation in schools within the context of gendered institutions. This argument is flawed in that it assumes schools are gender-neutral. I view schools as gendered institutions and contend that failing to recognize gender as an institutionalization of power only perpetuates inequalities, particularly in the context of Nepal's schools. Three objectives served as touchstones for the field research: (1) To examine the processes of gendering within the gendered institutions of family and school, through interviews eliciting attitudes and behavior of community members, parents/guardians, school head teachers (principals), and teachers in Jiri; (2) To investigate gendered behavior and interaction in classroom and school settings through direct observations and interviews; and (3) To examine the consequences of socially constructed gender boundaries through observations and interviews in school and home settings. This study examines how Jiri community members', parents'/guardians', teachers', and head teachers' gendered attitudes and behavior affect students' interactions, attitudes, perceptions, use of time, school attendance and participation. The research illustrates that although social constructions of gender constrain students, especially girl students, gender, as a social construction, is fluid---it can be negotiated and changed. This research is one of the first studies of structured interactions in classrooms in rural Nepal. It is also the most extensive collection of data on the gendered components of the education system in the specific context of Jiri. Lastly, this project also contributes to an understanding of the processes that reinforce and reproduce gender inequality in education.
The role of wire imperfections in micro magnetic traps for atoms
Creators: name: Esteve, Jerome
name: Aussibal, Christine
name: Schumm, Thorsten
name: Figl, Cristina
name: Mailly, Dominique
name: Bouchoule, Isabelle
name: Westbrook, Christopher
name: Aspect, Alain
Publisher: name: arXiv
Year: 2004
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: We present a quantitative study of roughness in the magnitude of the magnetic fieldproduced by a current carrying microwire, i.e. in the trapping potential for paramagnetic atoms.We show that this potential roughness arises from deviations in the wire current flow due to geometric fluctuations of the edges of the wire : a measurement of the potentialusing cold trapped atoms agrees with the potential computed from the measurement of the wire edge roughness by a scanning electronmicroscope.
A proof of Hall's conjecture on length of ray images under starlike mappings of order $α$
Creators: name: Hästö, Peter
name: Ponnusamy, Saminathan
Publisher: name: arXiv
Year: 2020
Subjects: subject: Complex Variables (math.CV)
subject: FOS: Mathematics
subject: 30C45, 30C35

description: Assume that $f$ lies in the class of starlike functions of order $α\in [0,1)$, that is, which are regular and univalent for $|z|<1$ and such that $${\rm Re} \left (\frac{zf'(z)}{f(z)} \right ) > α~\mbox{ for } |z|<1. $$ In this paper we show that for each $α\in [0,1)$, the following sharp inequality holds: $$ |f(re^{iθ})|^{-1} \int_{0}^{r}|f'(ue^{iθ})| du \leq \frac{Γ(\frac12)Γ(2-α)}{Γ(\frac32-α)} ~\mbox {for every $r<1$ and $θ$}. $$ This settles the conjecture of Hall (1980).
description: Ann. Sci. Fenn., to appear
Semileptonic Hyperon Decays
Creators: name: Cabibbo, Nicola
name: Swallow, Earl C.
name: Winston, Roland
Publisher: name: arXiv
Year: 2003
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: We review the status of hyperon semileptonic decays. The central issue is the $V_{us}$ element of the CKM matrix, where we obtain $V_{us}=0.2250 (27)$. This value is of similar precision, but higher, than the one derived from $K_{l3}$, and in better agreement with the unitarity requirement, $|V_{ud}|^2+|V_{us}|^2+|V_{ub}|^2=1$. We find that the Cabibbo model gives an excellent fit of the existing form factor data on baryon beta decays ($χ^{2} = 2.96$ for 3 degrees of freedom) with $F + D = 1.2670 \pm 0.0030$, $F - D = -0.341 \pm 0.016$, and no indication of flavour-SU(3)-breaking effects. We indicate the need of more experimental and theoretical work, both on hyperon beta decays and on $K_{l3}$ decays.
description: 37 pages, 8 figures, 4 tables, Final version of this material is scheduled to appear in the Annual Review of Nuclear and Particle Science Vol. 53
The role of bryophytes in forest decline and forest succession
Creators: name: Bliss, Shaan
name: Klinger, Lee
name: Bevirt, Brian
name: Barnes, Timothy
Publisher: name: University Corporation For Atmospheric Research (UCAR)
Year: 2000

This paper examines the bryophyte-paludification hypothesis introduced by Klinger (1990) which claims that mature upland forests develop into a stable climax bog community in the absence of large-scale disturbance. The primary mechanism of this process is dictated by the ground cover of bryophytes that kill fine feeder tree roots. This minute activity of forest decline elevates into a broader scale transition from forest to bog ecosystems. This phenomenon of forest decline is understood to be a natural process of ecosystem dynamics. Various positive and negative feedback mechanisms of bryophytes were investigated to obtain a better understanding for designing the research experiment. I describe an observational field experiment designed to test and prove the bryophyte-paludification hypothesis. Results from research indicate that due to the short sampling time frame, no initial comparisons can be drawn from the collected data. However, these results will be used as a baseline to compare subsequent samplings in the future.
Observation of anomalously strong penetration of terahertz electric field through terahertz-opaque gold films into a GaAs/AlGaAs quantum well
Creators: name: Ganichev, S. D.
name: Danilov, S. N.
name: Kronseder, M.
name: Schuh, D.
name: Gronwald, I.
name: Bougeard, D.
name: Ivchenko, E. L.
name: Shul'man, A. Ya.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Applied Physics (physics.app-ph)
subject: FOS: Physical sciences

description: We observe an anomalously high electric field of terahertz (THz) radiation acting on a two-dimensional electron gas (2DEG) placed beneath a thin gold film, which, however, is supposed to be opaque at THz frequencies. We show that the anomalously strong penetration of the THz electric field through a very high conductive gold film emerges if two conditions are fulfilled simultaneously: (i) the film's thickness is less than the skin depth and (ii) the THz electric field is measured beneath the film at distances substantially smaller than the radiation wavelength. We demonstrate that under these conditions the strength of the field acting on a 2DEG is almost the same as it would be in the absence of the gold film. The effect is detected for macroscopically homogeneous perforation-free gold films illuminated by THz-laser radiation with a spot smaller than the film area. This eliminates the near-field of the edge diffraction as a possible cause of the anomalous penetration. The microscopic origin of the effect remains unexplained in its details, yet. The observed effect can be used for the development of THz devices based on two-dimensional materials requiring robust highly conducting top gates placed at less than nanometer distance from the electron gas location.
Test missilistico russo mette a rischio la Iss
Creators: Marco Malaspina
Publisher: name: Media Inaf
Year: 2021

Indignazione Usa per un test missilistico, condotto ieri dalla Russia, che ha provocato una pericolosa nube di detriti, costringendo la Nasa a mettere in atto procedure di sicurezza sulla Stazione spaziale internazionale. La condanna della Nasa è arrivata poche ore dopo quella dell’amministrazione Biden, che attraverso il Dipartimento di Stato ha parlato di test “pericoloso e irresponsabile”
title: Life across the divide: Comparative Studies of the Ecology and Physiology of Species across the Antarctic Intertidal Zone
Creators: name: Waller, Catherine L
Publisher: name: The Open University
Year: 2007

description: This thesis describes the first detailed comparative study of Antarctic communities across the gradient of environmental conditions from terrestrial to marine zones. Sampling was undertaken at both sub-Antarctic (Scotia Arc) and Peninsula sites. This study is also the most detailed and comprehensive investigation of intertidal assemblages south of 60°S undertaken to date.

 Supralittoral, intertidal and, where possible, shallow sublittoral habitats were sampled along a latitudinal gradient from the Falkland Islands through the Scotia Arc (Bird Island, South Georgia and Signy Island (South Orkney Islands)) over one austral summer. Peninsula sites, in the vicinity of Rothera Research Station (Adelaide Island 67° 34.5’S), were studied in more detail over two austral summers, and one point sample was undertaken during the austral winter at Rothera Research Station.

 Contrary to the findings of previous studies, the Antarctic intertidal was found to support an unexpectedly rich and diverse community, with a total of 61 species being found at sites around Rothera Research Station, Adelaide Island. This is more than double the previous maximum richness reported in an Antarctic study. Intertidal assemblages at more northern Scotia Arc sites were less diverse and numerically abundant, the most depauperate sites being on Bird Island and South Georgia.

 Many of the taxa found are permanent residents in the intertidal near Rothera Research Station. Four-year-old colonies of the bryozoan Inversiula nutrix were found alive in summer samples, and a winter excavation of only 1 m2 of the intertidal icefoot revealed 17 species of both mobile and sessile taxa alive and present under the outer layer of rocks. The taxa present were predominantly marine species with only one possibly obligate intertidal animal being found, the halacarid mite Rhombognathus gressitti.

 The assemblages were virtually all located beneath the outer scoured surface of the intertidal rock matrix, in protected interstices. Both abundance and size of taxa increased with depth through the cobble boulder matrix suggesting that they are exploiting protected microhabitats in order to survive in this extreme environment.

 Preliminary ecophysiological studies suggest that the limpet Nacella concinna is capable of freeze tolerance and is able to survive all of the osmotically active water freezing, whilst the nemertean Antarctonemertes validum shows evidence of the presence of thermal hysteresis proteins (THPs). As such this is the first Antarctic and only the second marine invertebrate likely to possess THPs.
Meteora sulla Sicilia, segnalazioni da Agrigento
Creators: Gloria Nobile
Publisher: name: Media Inaf
Year: 2021

Avvistata giovedì scorso attorno alle 17:30, non si sa se qualche frammento sia effettivamente giunto a terra, né si conosce con precisione la zona dell’eventuale caduta, ma ci sono alcune segnalazioni. Ne parliamo con Carmelo Falco, fisico e collaboratore del centro astronomico Gal Hassin di Isnello, che ha potuto osservare l’evento personalmente
Preziosi indizi sul mistero dei pianeti mancanti
Creators: Maura Sandri
Publisher: name: Media Inaf
Year: 2021

La formazione dei pianeti è una spiegazione plausibile per gli anelli e i gap osservati nei dischi di polvere e gas attorno alle giovani stelle. Tuttavia, tale teoria ha difficoltà a spiegare perché sia così raro trovare pianeti vicino agli anelli. Nuove simulazioni, avvalorate da osservazioni, mostrano che dopo aver creato un anello un pianeta può allontanarsi lasciandoselo alle spalle. Tutti i dettagli su ApJ
Additional file 1 of Gas chromatography-mass spectrometry analysis, phytochemical screening and antiprotozoal effects of the methanolic Viola tricolor and acetonic Laurus nobilis extracts
Creators: name: Batiha, Gaber El-Saber
name: Amany Magdy Beshbishy
name: Alkazmi, Luay
name: Oluyomi Stephen Adeyemi
name: Nadwa, Eman
name: Rashwan, Eman
name: Amany El-Mleeh
name: Igarashi, Ikuo
Publisher: name: figshare
Year: 2020
Subjects: subject: Biochemistry
subject: Space Science
subject: Medicine
subject: Cell Biology
subject: Pharmacology
subject: Biotechnology
subject: 39999 Chemical Sciences not elsewhere classified
subject: FOS: Chemical sciences
subject: Ecology
subject: FOS: Biological sciences
subject: Developmental Biology
subject: Hematology

description: Additional file 1: Table S1. The IC50 and selective indexes value of ATV and DMA.
The World Tobacco Market-Government Intervention and Multilateral Policy Reform
Creators: name: Grise, Verner N.
name: Grise, Verner N.
Publisher: name: Unknown
Year: 1990
Subjects: subject: Crop Production/Industries
subject: International Relations/Trade
subject: Tobacco
subject: trade
subject: production
subject: trade liberalization

description: Tobacco and tobacco products are produced and traded throughout the world. About 30 percent of the world's tobacco is traded and even more would move between countries but for restrictions on imports. Numerous tariff and nontariff trade barriers discourage trade in tobacco. If freer trade existed, the U.S. quality and cost advantages would likely lead to larger exports of leaf and products to a number of countries. [his report describes world tobacco production and trade, catalogs the trade policies of the major producing and consuming countries, and examines the potential effects of more liberalized trade on the world tobacco market.
Combining satellite imagery and in situ plume composition in predicting isoprene concentration and plume sources
Creators: name: Zabel, Jennifer
Publisher: name: University Corporation For Atmospheric Research (UCAR)
Year: 1999

There are two main compounds involved in the production of tropospheric ozone (O3). They are NOx and volatile organic compounds (VOCs). The sources of NOx and VOCs can be either biogenic or anthropogenic. During the 1999 Southern Oxidant Study (SOS) air samples were collected in stainless steel canisters aboard the NOAA P3 aircraft. These canisters were then FedEx'd to the NCAR laboratory to be analyzed. Each canister was analyzed on a flame ionization detector (FID) Hewlett Packard 1000.
Temporal and probabilistic comparisons of epidemic interventions
Creators: name: Boudreau, Mariah C.
name: Allen, Andrea J.
name: Roberts, Nicholas J.
name: Allard, Antoine
name: Hébert-Dufresne, Laurent
Publisher: name: arXiv
Year: 2023
Subjects: subject: Populations and Evolution (q-bio.PE)
subject: FOS: Biological sciences

description: Forecasting disease spread is a critical tool to help public health officials design and plan public health interventions.However, the expected future state of an epidemic is not necessarily well defined as disease spread is inherently stochastic, contact patterns within a population are heterogeneous, and behaviors change. In this work, we use time-dependent probability generating functions (PGFs) to capture these characteristics by modeling a stochastic branching process of the spread of a disease over a network of contacts in which public health interventions are introduced over time. To achieve this, we define a general transmissibility equation to account for varying transmission rates (e.g. masking), recovery rates (e.g. treatment), contact patterns (e.g. social distancing) and percentage of the population immunized (e.g. vaccination). The resulting framework allows for a temporal and probabilistic analysis of an intervention's impact on disease spread, which match continuous-time stochastic simulations that are much more computationally expensive.To aid policy making, we then define several metrics over which temporal and probabilistic intervention forecasts can be compared: Looking at the expected number of cases and the worst-case scenario over time, as well as the probability of reaching a critical level of cases and of not seeing any improvement following an intervention.Given that epidemics do not always follow their average expected trajectories and that the underlying dynamics can change over time, our work paves the way for more detailed short-term forecasts of disease spread and more informed comparison of intervention strategies.
description: 20 pages, 5 figures
Note on Bound States and the Bekenstein Bound
Creators: name: Marolf, Donald
name: Roiban, Radu
Publisher: name: arXiv
Year: 2004
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In this brief note we draw attention to examples of quantum field theories which may hold interesting lessons for attempts to devise a precise formulation of the Bekenstein bound. Our comments mirror the recent results of Bousso (hep-th/0310223) indicating that the species problem remains an issue for precise formulations of this bound.
description: 6 pages, JHEP style
Centris (Paracentris) harbisoni Snelling 1974
Creators: name: Pedro, Diego De
name: Ceccarelli, Fadia Sara
name: Sagot, Philippe
name: López-Reyes, Eulogio
name: Mullins, Jessica L.
name: Mérida-Rivas, Jorge A.
name: Falcon-Brindis, Armando
name: Griswold, Terry
name: Ascher, John S.
name: Gardner, Joel
name: Ayala, Ricardo
name: Vides-Borrell, Eric
name: Vandame, Rémy
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy

description: Centris (Paracentris) harbisoni Snelling, 1974
Endemic
[Holotype: LACM; ♂ Bahía San Francisquito, Baja California, Mexico; April 3, 1947]
Centris harbisoni is an endemic species of the BCP. Snelling (1974) described this species based on specimens collected from the Lower Colorado Desert in San Francisquito, BC. We reviewed the holotype specimen and paratypes (LACM). Additionally, the BBPT collected 7 males, and 3 females in the Vizcaíno Desert, Magdalena Plains, and Gulf Coast regions in March 2021. Voucher specimens are in MABC (4 ♂, 2 ♀), and ECOAB (3 ♂, 1 ♀). See fig. 88.
description: Published as part of Pedro, Diego De, Ceccarelli, Fadia Sara, Sagot, Philippe, López-Reyes, Eulogio, Mullins, Jessica L., Mérida-Rivas, Jorge A., Falcon-Brindis, Armando, Griswold, Terry, Ascher, John S., Gardner, Joel, Ayala, Ricardo, Vides-Borrell, Eric & Vandame, Rémy, 2024, Revealing the Baja California Peninsula's Hidden Treasures: An Annotated checklist of the native bees (Hymenoptera: Apoidea: Anthophila), pp. 1-391 in Zootaxa 5522 (1) on page 149, DOI: 10.11646/zootaxa.5522.1.1, http://zenodo.org/record/13920532
A Simulation Model of United States Sugar Beet Acreage Response
Creators: name: Wallace, Henry N.
name: Carman, Hoy F.
name: Wallace, Henry N.
name: Carman, Hoy F.
Publisher: name: Unknown
Year: 1979
Subjects: Research Methods/ Statistical Methods

description: U.S. sugar beet acreage varies considerably as producers adjust to expected prices of sugar beets and alternative crops. This paper discusses the specification of a regional supply response simulation model and presents estimated supply elasticities. The model is used to project regional sugar beet acreage to 1990 under three alternative scenarios.
PredRecon: A Prediction-boosted Planning Framework for Fast and High-quality Autonomous Aerial Reconstruction
Creators: name: Feng, Chen
name: Li, Haojia
name: Gao, Fei
name: Zhou, Boyu
name: Shen, Shaojie
Publisher: name: arXiv
Year: 2023
Subjects: subject: Robotics (cs.RO)
subject: FOS: Computer and information sciences

description: Autonomous UAV path planning for 3D reconstruction has been actively studied in various applications for high-quality 3D models. However, most existing works have adopted explore-then-exploit, prior-based or exploration-based strategies, demonstrating inefficiency with repeated flight and low autonomy. In this paper, we propose PredRecon, a prediction-boosted planning framework that can autonomously generate paths for high 3D reconstruction quality. We obtain inspiration from humans can roughly infer the complete construction structure from partial observation. Hence, we devise a surface prediction module (SPM) to predict the coarse complete surfaces of the target from the current partial reconstruction. Then, the uncovered surfaces are produced by online volumetric mapping waiting for observation by UAV. Lastly, a hierarchical planner plans motions for 3D reconstruction, which sequentially finds efficient global coverage paths, plans local paths for maximizing the performance of Multi-View Stereo (MVS), and generates smooth trajectories for image-pose pairs acquisition. We conduct benchmarks in the realistic simulator, which validates the performance of PredRecon compared with the classical and state-of-the-art methods. The open-source code is released at https://github.com/HKUST-Aerial-Robotics/PredRecon.
description: Accepted by ICRA2023; Code: https://github.com/HKUST-Aerial-Robotics/PredRecon; Video: https://www.youtube.com/watch?v=ek7yY_FZYAc
Moving beyond enrollment numbers: An in- depth look at gender inequality in schools in rural Nepal
Creators: name: Rothchild, Jennifer Renae
Publisher: name: American University
Year: 2023

description: This dissertation examines the complexities of gender inequality within schools in Jiri, Nepal. While it has been argued in the literature that equal numbers of girls and boys in schools will remedy many social and economic problems, much of the research and development efforts regarding girls and schools fails to consider access to and participation in schools within the context of gendered institutions. This argument is flawed in that it assumes schools are gender-neutral. I view schools as gendered institutions and contend that failing to recognize gender as an institutionalization of power only perpetuates inequalities, particularly in the context of Nepal's schools. Three objectives served as touchstones for the field research: (1) To examine the processes of gendering within the gendered institutions of family and school, through interviews eliciting attitudes and behavior of community members, parents/guardians, school head teachers (principals), and teachers in Jiri; (2) To investigate gendered behavior and interaction in classroom and school settings through direct observations and interviews; and (3) To examine the consequences of socially constructed gender boundaries through observations and interviews in school and home settings. This study examines how Jiri community members', parents'/guardians', teachers', and head teachers' gendered attitudes and behavior affect students' interactions, attitudes, perceptions, use of time, school attendance and participation. The research illustrates that although social constructions of gender constrain students, especially girl students, gender, as a social construction, is fluid---it can be negotiated and changed. This research is one of the first studies of structured interactions in classrooms in rural Nepal. It is also the most extensive collection of data on the gendered components of the education system in the specific context of Jiri. Lastly, this project also contributes to an understanding of the processes that reinforce and reproduce gender inequality in education.
Diagnosing sources of error in the cloud parameterizations of the NCAR Climate Community Model
Creators: name: Vigh, Jonathan
name: Norris, Joel
Publisher: name: University Corporation For Atmospheric Research (UCAR)
Year: 1999

The goal of this study is to find biases related to incorrectly parameterized cloud processes in CCM3 and prototype versions of CCM4, the atmospheric component of the NCAR Climate System Model, version 1. The variables of low, mid, and high cloudiness, cloud radiative forcing, and precipitation are investigated through the use of seasonal climatologies. The frequency distribution of cloudiness over cloud top pressure and cloud optical thickness is also investigated for conditions of ascent and descent in the North Pacific during July 1988. Biases include too much low cloudiness over winter land and too little over winter oceans, the misplacement of deep convection, poor stratocumulus representation, and missing tropical and subtropical middle cloudiness. Several of these deficiencies may be related to moisture transport in and above the boundary layer, while others probably result from the lack of a correct physical parameterization of important small scale processes.
Affine algebraic super-groups with integral
Creators: name: Masuoka, Akira
name: Shibata, Taiki
name: Shimada, Yuta
Publisher: name: arXiv
Year: 2020
Subjects: subject: Algebraic Geometry (math.AG)
subject: FOS: Mathematics
subject: 14L15, 14M30, 16T05

description: We generalize to the super context, the known fact that if an affine algebraic group $G$ over a commutative ring $k$ acts freely (in an appropriate sense) on an affine scheme $X$ over $k$, then the dur sheaf $X\tilde{\tilde{/}}G$ of $G$-orbits is an affine scheme in the following two cases: (I) $G$ is finite; (II) $k$ is a field, and $G$ is linearly reductive. An emphasize is put on the more difficult generalization in the second case; the replaced assumption then is that an affine algebraic super-group $G$ over an arbitrary field has an integral. Those super-groups which satisfy the assumption are characterized, and are seen to form a large class if $\operatorname{char}k=0$. Hopf-algebraic techniques including bosonization are applied to prove the results.
description: Made very minor changes and corrections; final version to appear in Comm. Algebra
THE U.S. WATERMELON INDUSTRY
Creators: name: Allred, Amy J.
name: Lucier, Gary
name: Allred, Amy J.
name: Lucier, Gary
Publisher: name: Unknown
Year: 1990
Subjects: subject: Crop Production/Industries
subject: Demand and Price Analysis
subject: Marketing
subject: FOS: Economics and business
subject: Watermelon
subject: supply
subject: utilization
subject: trade
subject: prices
subject: marketing

description: Watermelon production and utilization declined from 1960 to 1980. However, recent evidence indicates that since 1980 both aggregate production and domestic utilization have expanded. This study reviews supply and utilization trends, prices, transportation, packaging, marketing, cash receipts, and costs of producing watermelons. It also documents historical industry changes, and reviews the research and promotion program, enacted by the industry in April 1989.
Un pezzo di Luna è diventato un asteroide?
Creators: Albino Carbognani
Publisher: name: Media Inaf
Year: 2021

Recenti osservazioni spettroscopiche sull’asteroide near-Earth (469219) Kamoʻoalewa indicano che potrebbe trattarsi di un frammento di roccia della superficie lunare scagliato nello spazio in seguito a un impatto avvenuto nel passato. In realtà le osservazioni non sono conclusive e saranno necessari molti più dati per confermare o escludere questa ipotesi
Soliton Confinement in a Quantum Circuit
Creators: name: Roy, Ananda
name: Lukyanov, Sergei L.
Publisher: name: arXiv
Year: 2023
Subjects: subject: Quantum Physics (quant-ph)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Confinement of topological excitations into particle-like states - typically associated with theories of elementary particles - are known to occur in condensed matter systems, arising as domain-wall confinement in quantum spin chains. However, investigation of confinement in the condensed matter setting has rarely ventured beyond lattice spin systems. Here, we analyze the confinement of sine-Gordon solitons into mesonic bound states in a one-dimensional, quantum electronic circuit~(QEC) array, constructed using experimentally-demonstrated circuit elements: Josephson junctions, capacitors and $0-π$ qubits. The interactions occurring naturally in the QEC array, due to tunneling of Cooper-pairs and pairs of Cooper-pairs, give rise to a non-integrable, interacting, lattice model of quantum rotors. In the scaling limit, the latter is described by the quantum sine-Gordon model, perturbed by a cosine potential with a different periodicity. We compute the string tension of confinement of sine-Gordon solitons and the changes in the low-lying spectrum in the perturbed model. The scaling limit is reached faster for the QEC array compared to conventional spin chain regularizations, allowing high-precision numerical investigation of the strong-coupling regime of this non-integrable quantum field theory. Our results, obtained using the density matrix renormalization group method, could be verified in a quench experiment using state-of-the-art QEC technologies.
description: 6 + 12 pages (version accepted in Nature Communications)
Understanding self -employment success among participants of microenterprise training programs
Creators: name: Soto, Enrique
Publisher: name: American University
Year: 2023

description: Microenterprise initiatives have gained popularity in the United States due to their widespread use and effectiveness in Third World countries as strategies to alleviate poverty and foster development, and more recently by changes in welfare policies limiting benefits and imposing work requirements on welfare recipients. Microenterprise training supporters consider that this type of effort have positive results in the economic well being of trainees and makes them more likely to run microbusinesses that will contribute to improve their living standard. Drawing on theories of entrepreneurship and empirical studies about self-employment initiatives, and using data from the Self-Employment Learning Project (SELP) of the Economic Opportunities Program of the Aspen Institute, this dissertation seeks to identify predictors of business success among individuals who received self-employment training services (loans, technical support, classroom training) from seven microenterprise training programs operating in the United States. SELP's participant survey followed a random sample of 405 microentrepreneurs for five years through five waves of interviews, collecting data on their employment status, earnings, income, training program participation, business operation and household and demographic characteristics. Individuals in the training programs were self-selected but the sample of SELP's survey was randomized. However, because of the lack of a control group this study's results are generalizable only to the population of participants in the seven microenterprise programs in the Aspen study. Six models of self-employment success using logistic regression analyses were tested: (1) business earnings push family income above 150% of poverty threshold at Wave 5; (2) greater business earnings at Wave 5; (3) greater personal earnings at Wave 5; (4) greater personal assets at Wave 5; (5) lower means-tested benefits at Wave 5; and (6) with an open business at Wave 5. Predictors included: demographic characteristics (age, gender, race/ethnicity, marital status, household composition), owner resources and characteristics (human capital and financial resources such as previous business experience, hours worked, educational level, household net worth, presence of other adults in the household), and program training characteristics (provision of credit, hours of program assistance). Complete data available for testing the models ranged between 148 and 191 cases out of 269 respondents in the last wave (Wave 5). Significant predictors were found for five models, and included gender, age, being self-employed, marital status, educational level, hours of program assistance, and household net worth. Implications for microenterprise programs were outlined in five areas: training for women, follow-up services, training program characteristics, educational level and program assistance, and provision of credit.
Proximity-induced quasi-one-dimensional superconducting quantum anomalous Hall state: a promising scalable top-down approach towards localized Majorana modes
Creators: name: Atanov, Omargeldi
name: Tai, Wai Ting
name: Xie, Ying-Ming
name: Ng, Yat Hei
name: Hammond, Molly A.
name: Ho, Tin Seng Manfred
name: Koo, Tsin Hei
name: Li, Hui
name: Ho, Sui Lun
name: Lyu, Jian
name: Chong, Sukong
name: Zhang, Peng
name: Tai, Lixuan
name: Wang, Jiannong
name: Law, Kam Tuen
name: Wang, Kang L.
name: Lortz, Rolf
Publisher: name: arXiv
Year: 2023
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: In this work, ~100 nm wide quantum anomalous Hall insulator (QAHI) nanoribbons are etched from a two-dimensional QAHI film. One part of the nanoribbon is covered with superconducting Nb, while the other part is connected to an Au lead via two-dimensional QAHI regions. Andreev reflection spectroscopy measurements were performed, and multiple in-gap conductance peaks were observed in three different devices. In the presence of an increasing magnetic field perpendicular to the QAHI film, the multiple in-gap peak structure evolves into a single zero-bias conductance peak (ZBCP). Theoretical simulations suggest that the measurements are consistent with the scenario that the increasing magnetic field drives the nanoribbons from a multi-channel occupied regime to a single channel occupied regime, and that the ZBCP may be induced by zero energy Majorana modes as previously predicted [24]. Although further experiments are needed to clarify the nature of the ZBCP, we provide initial evidence that quasi-1D QAHI nanoribbon/superconductor heterostructures are new and promising platforms for realizing zero-energy Majorana modes.
The ozone deficit in the stratosphere and mesosphere
Creators: name: Szymczak, Amanda
name: Sandor, Brad
Publisher: name: University Corporation For Atmospheric Research (UCAR)
Year: 1999

Modifications were made to a photochemical model to try to correct its predictions of O₃, OH, HO₂ and ClO concentrations in the stratosphere and mesosphere. Both these regions of the atmosphere were examined to see if the modifications would improve the simulations in both areas. The rate of the reaction of HO₂+O→OH+O₂ was reduced by 40%. The reaction ClO+OH→HCl+O₂ was added to the model at 0%, 4% and 6% branching ratios. A new rate constant for ClO+OH→ products, k(T)=(8.9±2.6)x10minustwelve exp(295±90/T)(Kegley-Owen et al., 1999), was also examined. Although these significantly improved model results for concentrations of ClO, OH, HO₂ and O₃ in the stratosphere and mesosphere, they did not completely resolve discrepancies between the model predictions and measurements.
Identifying young gamma-ray burst fossils
Creators: name: Ramirez-Ruiz, Enrico
Publisher: name: arXiv
Year: 2004
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The recent reports of temporal and spectral peculiarities in the early stages of some afterglows suggest that we may be wrong in postulating a central engine which becomes dormant after the burst itself. A continually decreasing postburst relativistic outflow, such as put out by a decaying magnetar, may continue to be emitted for periods of days or longer, and we argue that it can be efficiently reprocessed by the ambient soft photon field radiation. Photons produced either by the postexplosion expansion of the progenitor stellar envelope or by a binary companion provide ample targets for the relativistic outflow to interact and produce high energy gamma-rays. The resultant signal may yield luminosities high enough to be detected with the recently launched Integral and the Glast experiment now under construction. Its detection will surely offer important clues for identifying the nature of the progenitor and possibly constraining whether some route other than single star evolution is involved in producing a rapidly rotating helium core which in turn, at collapse, triggers a burst.
description: 6 pages, 4 figures; final version
Prime comunicazioni wireless con neutroni veloci
Creators: Maura Sandri
Publisher: name: Media Inaf
Year: 2021

Un gruppo di ricercatori è riuscito a trasferire informazioni codificate digitalmente, modulando un campo di neutroni veloci. Sono state quindi dimostrate le potenzialità dei neutroni come mezzo per comunicazioni wireless per applicazioni in cui la trasmissione elettromagnetica convenzionale non è fattibile o risulta limitata. Tutti i dettagli su Nuclear Instruments and Methods in Physics Research