High prices for rare species can drive large populations extinct: the anthropogenic Allee effect revisited

Consumer demand for plant and animal products threatens many populations with extinction. The anthropogenic Allee effect (AAE) proposes that such extinctions can be caused by prices for wildlife products increasing with species rarity. This price-rarity relationship creates financial incentives to extract the last remaining individuals of a population, despite higher search and harvest costs. The AAE has become a standard approach for conceptualizing the threat of economic markets on endangered species. Despite its potential importance for conservation, AAE theory is based on a simple graphical model with limited analysis of possible population trajectories. By specifying a general class of functions for price-rarity relationships, we show that the classic theory can understate the risk of species extinction. AAE theory proposes that only populations below a critical Allee threshold will go extinct due to increasing price-rarity relationships. Our analysis shows that this threshold can be much higher than the original theory suggests, depending on initial harvest effort. More alarmingly, even species with population sizes above this Allee threshold, for which AAE predicts persistence, can be destined to extinction. Introducing even a minimum price for harvested individuals, close to zero, can cause large populations to cross the classic anthropogenic Allee threshold on a trajectory towards extinction. These results suggest that traditional AAE theory may give a false sense of security when managing large harvested populations

The Dirty Third: Contributions of Southern Hip Hop to the Study of Regional Variation Within African American English

While there is well documented evidence of certain supra-regional features in African American English (AAE) phonology and morphosyntax (for example, see Labov 1972; Rickford 1999; Baugh 2000; Green 2002), recent trends in the study of linguistic variation suggest that the homogeneity of the variety has been largely overstated (Mallinson & Wolfram 2002; Friedland 2003; Wolfram 2003). For the most part, contemporary AAE influences on mainstream language have originated from varieties spoken in the northeast and on the west coast which have evolved independently of one another over the past forty years, and which vary in significant ways from southern AAE; however, the most popular linguistic styles of rap music and hip hop culture have shifted over the years as artists from various regions (the West Coast, the Midwest, and the South) have put their particular speech communities on the map in the Black Public Sphere. We argue here that as southern American rappers have become more dominant in the popular music scene, like East and West coast rappers before them, they have had a significant impact on the AAE spoken by hip hop’s insiders, and they have also influenced the language of mainstream speakers as well. This paper builds on Smitherman’s insights on Hip Hop Linguistics (2006) even as it explores a more recent sociolinguistic phenomenon: the imminent emergence of southern AAE forms in the music and lyrics of the most popular rap artists of this decade and the attendant influence that these forms might have on AAE in general. Preliminary findings suggest that the linguistic effects of southern rap on AAE (and to a lesser extent, mainstream varieties) are not only evident in the lexicon (which could be dismissed simply as fleeting slang), but also in the phonology of the variety, providing us with a more complete understanding of contemporary AAE and the ways in which the variety continues to develop

Spectral absorption of biomass burning aerosol determined from retrieved single scattering albedo during ARCTAS

Actinic flux, as well as aerosol chemical and optical properties, were measured aboard the NASA DC-8 aircraft during the ARCTAS (Arctic Research of the Composition of the Troposphere from Aircraft and Satellites) mission in Spring and Summer 2008. These measurements were used in a radiative transfer code to retrieve spectral (350-550 nm) aerosol single scattering albedo (SSA) for biomass burning plumes encountered on 17 April and 29 June. Retrieved SSA values were subsequently used to calculate the absorption Angstrom exponent (AAE) over the 350-500 nm range. Both plumes exhibited enhanced spectral absorption with AAE values that exceeded 1 (6.78 ± 0.38 for 17 April and 3.34 ± 0.11 for 29 June). This enhanced absorption was primarily due to organic aerosol (OA) which contributed significantly to total absorption at all wavelengths for both 17 April (57.7%) and 29 June (56.2%). OA contributions to absorption were greater at UV wavelengths than at visible wavelengths for both cases. Differences in AAE values between the two cases were attributed to differences in plume age and thus to differences in the ratio of OA and black carbon (BC) concentrations. However, notable differences between AAE values calculated for the OA (AAEOA) for 17 April (11.15 ± 0.59) and 29 June (4.94 ± 0.19) suggested differences in the plume AAE values might also be due to differences in organic aerosol composition. The 17 April OA was much more oxidized than the 29 June OA as denoted by a higher oxidation state value for 17 April (+0.16 vs. -0.32). Differences in the AAEOA, as well as the overall AAE, were thus also possibly due to oxidation of biomass burning primary organic aerosol in the 17 April plume that resulted in the formation of OA with a greater spectral-dependence of absorption. © Author(s) 2012. CC Attribution 3.0 License

PENGEMBANGAN DAN PENGGUNAAN ASESMEN ALTERNATIF ELEKTRONIK (AAE) DALAM MENILAI SIKAP ILMIAH DAN PENGUASAAN KONSEP SISWA PADA KONSEP SISTEM PERTAHANAN TUBUH

Penelitian ini bertujuan untuk memperoleh data tentang karakteristik penggunaan dan pengembangan asesmen alternatif elektronik (AAE) untuk menilai sikap ilmiah dan penguasaan konsep siswa pada konsep sistem pertahanan tubuh. Metode penelitian yang digunakan adalah deskriptif. Subjek penelitian adalah siswa kelas XI SMAN 1 Sumedang. Data dikumpulkan dengan menggunakan pertanyaan terbuka, skala sikap soal penguasaan konsep, lembar angket, format wawancara, dan catatan lapangan. Kegiatan penelitian dibagi menjadi tahap pengembangan AAE dan tahap pelaksanaan AAE. Tahap pengembangan AAE meliputi task AAE, instrumen AAE, dan fitur-fitur AAE. Tahap pelaksanaan AAE meliputi tahap uji coba dan penggunaan AAE. Hasil penelitian menunjukkan AAE yang dikembangkan memiliki karakteristik: 1) AAE berkedudukan sebagai assessment for learning, assessment as learning sekaligus juga sebagai assessment of learning; 2) AAE memuat fitur pertanyaan terbuka dan skala sikap untuk mengungkap sikap ilmiah siswa; 3) AAE didokumentasikan secara offline untuk feasibilitas penggunaannya di sekolah; 4) AAE memiliki fitur task yang terintegrasi dengan bahan ajar dan proses kegiatan pembelajaran; 5) AAE dapat mengungkap kemampuan kognitif siswa melalui fitur tes penguasaan konsep; 6) AAE menyediakan task dengan ilustrasi dan kegiatan praktikum virtual yang menyerupai situasi nyata; 7) AAE memiliki kemampuan menyimpan hasil kerja siswa. Sikap ilmiah yang diungkap dengan pertanyaan terbuka memberikan informasi yang lebih jelas dan mendetail karena disertai alasan bila dibandingkan dengan yang diungkap oleh skala sikap. Capaian rata-rata sikap ilmiah siswa yang diungkap dengan pertanyaan terbuka memiliki kategori kurang (35,2) untuk indikator skpetis, cukup (42,7) untuk mengutamakan bukti, kurang sekali (16,5) untuk rasa ingin tahu, cukup (47,2) untuk menerima perbedaan, dan baik (73,1) untuk bersikap positif terhadap kegagalan. Penguasaan konsep siswa yang diungkap dengan tes penguasaan konsep berada pada kategori baik (62,6%). Keterbatasan perangkat AAE yang ditemukan yaitu pemberian feedback tidak dapat dilakukan secara otomatis oleh software AAE karena keterbatasan software dalam merespon jawaban siswa yang sangat beragam. Guru dan siswa menanggapi positif terhadap penggunaan AAE, meskipun dalam penerapannya mengalami beberapa kendala. Dengan demikian, penggunaan AAE ini dapat diaplikasikan dalam pembelajaran dan asesmen sehari-hari untuk menilai sikap ilmiah dan penguasaan konsep siswa. Kata kunci: sikap ilmiah, penguasaan konsep, asesmen alternatif elektronik (AAE

Remote sensing of soot carbon – Part 2: Understanding the absorption Ångström exponent

Recently, some authors have suggested that the absorption Ångström exponent (AAE) can be used to deduce the component aerosol absorption optical depths (AAODs) of carbonaceous aerosols in the AERONET database. This AAE approach presumes that AAE ≪ 1 for soot carbon, which contrasts the traditional small particle limit of AAE = 1 for soot carbon. Thus, we provide an overview of the AERONET retrieval, and we investigate how the microphysics of carbonaceous aerosols can be interpreted in the AERONET AAE product. We find that AAE ≪ 1 in the AERONET database requires large coarse mode fractions and/or imaginary refractive indices that increase with wavelength. Neither of these characteristics are consistent with the current definition of soot carbon, so we explore other possibilities for the cause of AAE ≪ 1. AAE is related to particle size, and coarse mode particles have a smaller AAE than fine mode particles for a given aerosol mixture of species. We also note that the mineral goethite has an imaginary refractive index that increases with wavelength, is very common in dust regions, and can easily contribute to AAE ≪ 1. We find that AAE ≪ 1 can not be caused by soot carbon, unless soot carbon has an imaginary refractive index that increases with wavelength throughout the visible and near-infrared spectrums. Finally, AAE is not a robust parameter for separating carbonaceous absorption from dust aerosol absorption in the AERONET database

African American English-Speaking Children\u27s Judgments of Grammaticality: Effects of Clinical Status and Grammatical Structures

African American English (AAE)-speaking children’s ability to judge the grammaticality of sentences was evaluated by their clinical status and grammatical structure. The study originated from a need to understand more about the tense and agreement systems of AAE speakers with specific language impairment (SLI) relative to their typically developing (TD) AAE-speaking peers. Tense and agreement forms are typically excluded from the assessment and treatment of children who speak AAE in fear of misinterpreting a dialect difference as a language disorder. As a result, limited information exists about the tense and agreement systems of AAE-speaking children. The data were archival and from 91 AAE-speaking kindergartners (SLI = 34; TD = 57). The children’s judgments were elicited from the Rice/Wexler Test of Early Grammatical Impairment (Rice & Wexler, 2001). This test was designed for General American English (GAE). Given this, I first examined the items using A’ values and GAE as the dialect referent. Then I re-analyzed the data using percentages of acceptability and AAE as the dialect referent. Not surprisingly, the A¢ values based on GAE did not differ by clinical group. Although both groups earned higher A’ for the control forms than the zero forms, both groups performed at chance level on the zero forms. When AAE was used as the dialect referent and percentages of acceptability were examined, clinical differences were found, with the TD group accepting the AAE-appropriate overt forms at higher percentages than the SLI group. The TD group also showed greater discernment within their acceptability percentages when AAE-appropriate forms were compared to AAE-inappropriate forms, although both groups accepted the former forms at higher percentages than the latter. The findings indicate that AAE-speaking children with SLI are not as discerning as TD controls when asked to judge the grammatical acceptability of AAE-appropriate tense and agreement forms and when asked to judge the acceptability of AAE-appropriate and inappropriate forms. These findings contribute to the growing literature base that shows tense and agreement weaknesses in AAE-speaking children with SLI and calls for the inclusion of tense and agreement structures in dialect-appropriate assessments and treatments of SLI within AAE

Teacher Perceptions of African American English and Its Impact on Teacher Expectations

This applied dissertation was designed to examine teacher attitudes toward African-American English (AAE) and how those attitudes influence teacher expectations for students who speak AAE. Previous exposure to AAE as well as differences between teacher interaction with AAE speaking students and non-AAE speaking students was investigated. Teacher expectations are more strongly related to the later achievement of children from stigmatized groups, i.e., children from minority and/or low socioeconomic backgrounds; and teacher expectations have lasting effects on these students’ performances (Jussim & Harber, 2005). Since it is estimated that up to 80% of African-Americans living in the continental United States speak AAE (Amberg & Vause, 2009), it is imperative to look at teacher attitudes toward the dialect and to explore possible biases. Equally important is the examination of current teaching approaches used to instruct speakers of AAE. Negative attitudes or perceptions toward a child’s language may result in lower teacher expectations for AAE speakers in the classroom. Lower expectations could result in impediments to student learning. The writer used the African-American English Teacher Attitude Scale (AAETAS) to quantify teacher attitudes and perceptions toward AAE. Previous exposure to AAE was obtained through participant response. Observations of teacher-student interactions were conducted to obtain the frequency of interactions as a conveyance of expectations. Open-ended interview questions were posed to participants to gain additional insight into teacher attitudes and to understand how teachers approached teaching students who spoke AAE. This study suggests that previous exposure to AAE through coursework or professional development could possibly lead to teachers having more positive attitudes toward AAE speakers

All about Dat Bass or linguistic blackface: White pop artists and African American English

This work explores America\u27s love-hate relationship with African American English (AAE). As Linguist Geneva Smitherman points out, AAE is both stigmatized and superficially celebrated in the U.S. Focusing on White pop artist Meghan Trainor, I examine the role of AAE in her music and interviews and how her use of AAE relates to her image, the content of her songs, and how she is viewed. Even though some people benefit from its commodification, AAE and its native speakers continue to be discriminated against in most contexts. This work explores AAE\u27s status in American society through Trainor\u27s commodification of the language variety

The syntax of questions and variation in adult and child African American English

This dissertation is the first in-depth examination of the syntax of questions and question variation in African American English (AAE). Question syntax in AAE can vary among subject-auxiliary inversion (e.g., What did you eat?), non-inversion (e.g., Why I can’t play?), and auxiliary-less questions (e.g., What he said?). Historically, AAE question syntax, when considered at all, has been dismissed as essentially identical to mainstream English. Thus, commentary on AAE question syntax is limited to observing that auxiliaries may “delete” in auxiliary-less questions, and that subject-auxiliary inversion may be “absent” in non-inverted questions. In other words, question syntax in AAE has generally been represented as a derivation or deviation from mainstream English. In the first half of this thesis I provide a syntactic analysis of the three question types, and I argue that question variation in AAE—in contrast to question variation in MAE—is the product of true syntactic variation. I show that 1) auxiliary-less questions are not necessarily cases of deletion, but are rather generated by AAE-specific parametric settings that—due to a lack of covert movement— never call upon an auxiliary, and 2) variation among different question types is tightly constrained and predicted by grammatical factors, such as negation, auxiliary verb-type, and tense. In the second half of this thesis, I examine question patterns among AAE-speaking children based on a corpus of over 50 hours of elicited and spontaneous speech data from more than 80 AAE- and mainstream English-speaking children (ages 5-7) in a New Orleans elementary school. My analysis of these data show the following: 1) by age 5, child speakers of AAE already follow the same grammatical patterns constraining question variation that are documented in adult AAE, 2) variation is inherent to the syntax of AAE questions, and not an artifact of dialect-switching or social variation, and 3) the patterns in the children’s data support the analysis of AAE question syntax presented in the first half of this thesis.Linguistic