Psychometric evaluation of the Early/Late Preferences Scale

This paper examines the psychometric quality of the Early/Late Preferences Scale (PS) relative to that of the Composite Morningness Scale (CS). Questionnaires were completed by 670 undergraduate students aged 16-37 years (mean 22.5), of whom 64% were female. Both scales displayed satisfactory inter-item correlations and similar total mean scores to those reported previously, although the CS had higher variability. Principal axis factor analysis produced single-factor solutions for both scales, although loadings for Items 7 and 9 on the PS were low. Internal consistencies for both scales were good (PS=0.86, CS=0.90) with only a small improvement achieved by deleting Items 7 and 9 from the PS. Test-retest reliability over 11 weeks was good for both scales (PS=0.92, CS=0.89). Differences between morning, evening and intermediate groups in self-rated alertness at different times of day, and significant correlations with other indices of morning-evening orientation, provided evidence of validity for both scales. These results indicate that PS is psychometrically comparable with CS. In view of its simpler format and lower cultural specificity, PS may be considered a preferable measure for most applications.

Cenomanian (early Late Cretaceous) ammonoid faunas of Western Europe - Part II: Diversity patterns and the end-Cenomanian anoxic event

Diversity patterns of ammonoids are analyzed and compared with the timing of anoxic deposits around the Cenomanian/Turonian (C/T) boundary in the Vocontian, Anglo-Paris, and Monster basins of Western Europe. Differing from most previous studies, which concentrate on a narrow time span bracketing the C/T boundary, the present analysis covers the latest Albian to Early Turonian interval for which a high resolution, ammonoid-based biochronology, including 34 Unitary Associations zones, is now available. During the latest Albian-Middle Cenomanian interval, species richness of ammonoids reveals a dynamical equilibrium oscillating around an average of 20 species, whereas the Late Cenomanian-Early Turonian interval displays an equilibrium centered on an average value of 6 species. The abrupt transition between these two successive equilibria lasted no longer than two Unitary Associations. The onset of the decline of species richness thus largely predates the spread of oxygen-poor water masses onto the shelves, while minimal values of species richness coincide with the Cenomanian-Turonian boundary only. The decline of species richness during the entire Late Cenomanian seems to result from lower origination percentages rather than from higher extinction percentages. This result is also supported by the absence of statistically significant changes in the extinction probabilities of the poly-cohorts. Separate analyses of species richness for acanthoceratids and heteromorphs, the two essential components of the Cenomanian ammonoid community, reveal that heteromorphs declined sooner than acanthoceratids. Moreover, acanthoceratids showed a later decline at the genus level than at the species level. Such a decoupling is accompanied by a significant increase in morphological disparity of acanthoceratids, which is expressed by the appearance of new genera. Last, during the Late Cenomanian, paedomorphic processes, juvenile innovations and reductions of adult size dominated the evolutionary radiation of acanthoceratids. Hence, the decrease in ammonoid species richness and their major evolutionary changes significantly predates the spread of anoxic deposits. Other environmental constraints such as global flooding of platforms, warmer and more equable climate, as well as productivity changes better correlate with the timing of diversity changes and evolutionary patterns of ammonoids and therefore, provide more likely causative mechanisms than anoxia alone.

Early Jurassic to Early late Cretaceous radiolarians from the Santa Rosa accretionary complex (Northwestern Costa Rica)

In the circum-Pacific ophiolitic belts, when no other biogenic constituents are found, radiolarians have the potential to provide significant biostratigraph- ic information. The Santa Rosa Accretionary Complex, which crops out in several half-windows (Carrizal, Sitio Santa Rosa, Bahia Nancite, Playa Naranjo) along the south shores of the Santa Elena Peninsula in northwestern Costa Rica, is one of these little-known ophiolitic mélanges. It contains various oceanic assemblages of alkaline basalt, radiolarite and polymictic breccias. The radiolarian biochronology presented in this work is mainly based by correlation on the biozonations of Carter et al. (2010), Baumgartner et al. (1995b), and O'Dogherty (1994) and indicate an Early Jurassic to early Late Cretaceous (early Pliensbachian to earliest Turonian) age for the sediments associated with oceanic basalts or recovered from blocks in breccias or megabreccias. The 19 illus- trated assemblages from the Carrizal tectonic window and Sitio Santa Rosa contain in total 162 species belonging to 65 genera. The nomenclature of tecton- ic units is the one presented by (Baumgartner and Denyer, 2006). This study brings to light the Early Jurassic age of a succession of radiolarite, which was previously thought to be of Cretaceous age, intruded by alkaline basalts sills (Unit 3). The presence of Early Jurassic large reworked blocks in a polymictic megabreccia, firstly reported by De Wever et al. (1985) is confirmed (Unit 4). Therefore, the alkaline basalt associated with the radiolarites of these two units (and maybe also Units 5 and 8) could be of Jurassic age. In the Carrizal tectonic window, Middle to early Late Jurassic radiolarian chert blocks associ- ated with massive tholeitic basalts and Early Cretaceous brick-red ribbon cherts overlying pillow basalts are interpreted as fragments of a Middle Jurassic oceanic basement accreted to an Early Cretaceous oceanic Plate, in an intra-oceanic subduction context. Whereas, the knobby radiolarites and black shales of Playa Carrizal are indicative of a shallower middle Cretaceous paleoenvironment. Other remnants of this oceanic basin are found in Units 2, 6, and 7, which documented the rapid approach of the depocentre to a subduction trench during the late Early Cretaceous (Albian-Cenomanian), to possibly early Late Cretaceous (Turonian).

ML estimator and hybrid beamformer for multipath and interference mitigation in GNSS receivers

This paper addresses the estimation of the code-phase(pseudorange) and the carrier-phase of the direct signal received from a direct-sequence spread-spectrum satellite transmitter. Thesignal is received by an antenna array in a scenario with interferenceand multipath propagation. These two effects are generallythe limiting error sources in most high-precision positioning applications.A new estimator of the code- and carrier-phases is derivedby using a simplified signal model and the maximum likelihood(ML) principle. The simplified model consists essentially ofgathering all signals, except for the direct one, in a component withunknown spatial correlation. The estimator exploits the knowledgeof the direction-of-arrival of the direct signal and is much simplerthan other estimators derived under more detailed signal models.Moreover, we present an iterative algorithm, that is adequate for apractical implementation and explores an interesting link betweenthe ML estimator and a hybrid beamformer. The mean squarederror and bias of the new estimator are computed for a numberof scenarios and compared with those of other methods. The presentedestimator and the hybrid beamforming outperform the existingtechniques of comparable complexity and attains, in manysituations, the Cramér–Rao lower bound of the problem at hand.

Early, late or very late? Timing acquisition and bilingualism

Research on child bilingualism accounts for differences in the course and the outcomes of monolingual and different types of bilingual language acquisition primarily from two perspectives: age of onset of exposure to the language(s) and the role of the input (Genesee, Paradis, & Crago, 2004; Meisel, 2009; Unsworth et al., 2014). Some findings suggest that early successive bilingual children may pattern similarly to simultaneous bilingual children, passing through different trajectories from child L2 learners due to a later age of onset in the latter group. Studies on bilingual development have also shown that input quantity in bilingual acquisition is considerably reduced, i.e., in each of their two languages, bilingual children are likely exposed to much less input than their monolingual peers (Paradis & Genesee, 1996; Unsworth, 2013b). At the same time, simultaneous bilingual children develop and attain competence in the two languages, sometimes without even an attested age delay compared to monolingual children (Paradis, Genesee & Crago, 2011). The implication is that even half of the input suffices for early language development, at least with respect to ‘core’ aspects of language, in whatever way ‘core’ is defined.My aim in this article is to consider how an additional, linguistic variable interacts with age of onset and input in bilingual development, namely, the timing in L1 development of the phenomena examined in bilingual children’s performance. Specifically, I will consider timing differences attested in the monolingual development of features and structures, distinguishing between early, late or ‘very late’ acquired phenomena. I will then argue that this three-way distinction reflects differences in the role of narrow syntax: early phenomena are core, parametric and narrowly syntactic, in contrast to late and very late phenomena, which involve syntax-external or even language-external resources too. I explore the consequences of these timing differences in monolingual development for bilingual development. I will review some findings from early (V2 in Germanic, grammatical gender in Greek), late (passives) and very late (grammatical gender in Dutch) phenomena in the bilingual literature and argue that early phenomena can differentiate between simultaneous and (early) successive bilingualism with an advantage for the former group, while the other two reveal similarly (high or low) performance across bilingual groups, differentiating them from monolinguals. The paper proposes that questions about the role of age of onset and language input in early bilingual development can only be meaningfully addressed when the properties and timing of the phenomena under investigation are taken into account.

Consequences of Early Late-Pleistocene Megadroughts in Tropical Africa

Extremely arid conditions in tropical Africa occurred in several discrete episodes between 135 and 90 ka, as demonstrated by lake core and seismic records from multiple basins [Scholz CA, Johnson TC, Cohen AS, King JW, Peck J, Overpeck JT, Talbot MR, Brown ET, Kalindekafe L,Amoako PYO, et al. (2007) Proc Natl Acad SciUSA104:16416–16421]. This resulted in extraordinarily low lake levels, even in Africa’s deepest lakes.On the basis of well dated paleoecological records from Lake Malawi, which reflect both local and regional conditions, we show that this aridity had severe consequences for terrestrial and aquatic ecosystems. During the most arid phase, there was extremely low pollen production and limited charred-particle deposition, indicating insufficient vegetation to maintain substantial fires, and the Lake Malawi watershed experienced cool, semidesert conditions (<400 mm>/yr precipitation). Fossil and sedimentological data show that Lake Malawi itself, currently 706mdeep, was reduced to an ~125 m deep saline, alkaline, well mixed lake. This episode of aridity was far more extreme than any experienced in the Afrotropics during the Last Glacial Maximum (~35–15 ka). Aridity diminished after 95 ka, lake levels rose erratically, and salinity/alkalinity declined, reaching near-modern conditions after 60 ka. This record of lake levels and changing limnological conditions provides a framework for interpreting the evolution of the Lake Malawi fish and invertebrate species flocks. Moreover, this record, coupled with other regional records of early Late Pleistocene aridity, places new constraints on models of Afrotropical biogeographic refugia and early modern human population expansion into and out of tropical Africa.

Response of chironomid assemblages to environmental change during the early Late-glacial at Gerzensee, Switzerland

Prior to ca. 14,660 yr BP, during the early Late-glacial (Oldest Dryas), larval assemblages of Chironomidae (Insecta: Diptera) in Gerzensee, Switzerland, were dominated by cold stenothermic taxa as well as by taxa typical of subalpine lakes today. This was the coldest period of the entire sequence. After ca. 14,660 yr BP, in the Late Glacial Interstadial (Bølling–Allerød), a temperature increase is recorded by a sharp rise in the oxygen-isotope ratio in lake marl and by an increase in the organic-matter content of the sediments. Changes in the chironomid fauna then are consistent with rising temperatures. This warming trend is interrupted between 14,070 and 13,940 yr BP, coinciding with the GI-1d cold oscillation, but the change in the chironomid assemblage is more consistent with a response to increasing lake depth and density of aquatic macrophytes than falling temperature. A rise in cold-adapted chironomid taxa between 13,840 and 13,710 yr BP suggests that summer air temperatures may have declined. Changes in the chironomid assemblage after 13,710 yr BP suggest a decline in submerged macrophytes coupled with a rise in lake productivity and summer temperature, although the latter is not reflected in the oxygen-isotope record. This suggests that there may have been increasing seasonality during this period when summer temperatures were rising, driven by rising summer insolation, and winters becoming cooler, which is largely reflected in the oxygen-isotope record. A decline in thermophilic chironomids and a rise in cold-adapted taxa after 13,180 yr BP suggest a response to cooling at the beginning of the Gerzensee Oscillation.

Response of subfossil Cladocera in Gerzensee (Swiss Plateau) to early Late Glacial environmental change

Sub-fossil Cladocera were studied in a core from Gerzensee (Swiss Plateau) for the late-glacial periods of Oldest Dryas, Bølling, and Allerød. Cladocera assemblages were dominated by cold-tolerant littoral taxa Chydorus sphaericus, Acroperus harpae, Alonella nana, Alona affinis, and Alonella excisa. The rapid warming at the beginning of the Bølling (GI-1e) ca. 14,650 yr before present (BP: before AD 1950) was indicated by an abrupt 2‰ shift in carbonate δ18O and a clear change in pollen assemblages. Cladocera assemblages, in contrast, changed more gradually. C. sphaericus and A. harpae are the most cold-tolerant, and their abundance was highest in the earliest part of the record. Only 150–200 years after the beginning of the Bølling warming we observed an increase in less cold-tolerant A. excisa and A. affinis. The establishment of Alona guttata, A. guttata var. tuberculata, and Pleuroxus unicatus was delayed by ca. 350, 770, and 800 years respectively after the onset of the Bølling. The development of the Cladocera assemblages suggests increasing water temperatures during the Bølling/Allerød, which agrees with the interpretation by von Grafenstein et al. (2013-this issue) that decreasing δ18O values in carbonates in this period reflect increasing summer water temperatures at the sediment–water interface. Other processes also affected the Cladocera community, including the development and diversification of aquatic vegetation favourable for Cladocera. The record is clearly dominated by Chydoridae, as expected for a littoral core. Yet, the planktonic Eubosmina-group occurred throughout the core, with the exception of a period at ca. 13,760–13,420 yr BP. Lake levels reconstructed for this period are relatively low, indicating that the littoral location might have become too shallow for Eubosmina in that period.

Early - Late Miocene palaeoclimate data and palaefloras of 48 samples from Southern China

Southern China, especially Yunnan, has undergone high tectonic activity caused by the uplift of Himalayan Mountains during the Neogene, which led to a fast changing palaeogeography. Previous study shows that Southern China has been influenced by the Asian Monsoon since at least the Early Miocene. However, it is yet not well understood how intense the Miocene monsoon system was. In the present study, 63 fossil floras of 16 localities from Southern China are compiled and evaluated for obtaining available information concerning floristic composition, stratigraphic age, sedimentology, etc. Based on such reliable information, selected mega- and micro-floras have been analysed with the coexistence approach to obtain quantitative palaeoclimate data. Visualization of climate results in maps shows a distinct spatial differentiation in Southern China during the Miocene. Higher seasonalities of temperature and precipitation occur in the north and south parts of Southern China, respectively. During the Miocene, most regions of Southern China and Europe were both warm and humid. Central Eurasia was likely to be an arid center, which gradually spread westward and eastward. Our data provide information about Miocene climate patterns in Southern China and about the evolution of these patterns throughout the Miocene, and is also crucial to unravel and understand the climatic signals of global cooling and tectonic uplift.

Stable isotope composition and ice rafted debris in early Late Pliocene sediments from Maud Rise, South Atlantic

We have conducted an integrated study of ice-rafted debris (IRD) and oxygen isotopes (measured on Cibicides, Globigerina bulloides, and Neogloboquadrina pachyderma, using identical samples). We used samples from the early Late Pliocene Gauss Chron from ODP Site 114-704 on the Meteor Rise in the subantarctic South Atlantic. During the early Gauss Chron, the oxygen isotopic ratios are generally up to 0.5?-0.6? less than their respective Holocene values. The lowest values in this record can accommodate a warming of about 2.5°C or a sea-level rise of about 50 m, but not both, and probably result from some warming and a small reduction in global ice volume. Starting with isotope stage MG2 [ 3.23 Ma on the Berggren et al. ( 1985) time scale; 3.38 on the Shackleton et al. ( 1995b) time scale] oxygen-isotopic values generally increase (and oscillate about a Holocene mean). The first significant IRD appears at the same time. There is a subsequent increase in IRD amounts upsection. In order to reach the site, this material must have been transported by large, tabular icebergs derived from Antarctic ice shelves or ice tongues, similar to occasional, large modern icebergs. This combined record suggests strongly that the Antarctic ice sheet was essentially intact; some warming at the drill site is indicated, but not a major reduction in ice-volume on Antarctica.