Intersexual behaviour and effect of male and female intruders in the Tenerife skink (Chalcides viridanus). Is there any mate guarding?

Individuals avoid potential competitors accessing mates during reproductive periods staying close to the mate and chasing same-sex intruders. We studied intersexual relationships and the effect of intruders of each sex in male-female pairs of Chalcides viridanus. We analysed: (1) behaviour patterns of each pair member and the time they spent together during three successive days in March, April and May; and (2) interactions of intruder-resident of the same sex, during each of the three months. Sexual and monthly differences appeared in intersexual behaviour as the breeding season progressed. In each month, time together was significantly larger on the third trial day than in the two previous days but did not significantly change between months. Sexes did not significantly differ in intruder-resident behaviours, but male aggressive interactions were significantly larger in May. Intruder females performed higher frequencies of non-agonistic behaviours than residents. We discuss all these results considering the predictions of mate guarding hypothesis.

NGC 90: a hidden jellyfish galaxy?

ABSTRACT We study a peculiar galaxy NGC 90, a pair member of interacting system Arp 65 (NGC 90/93), using the long-slit spectral observations carried out at the Russian 6-m telescope BTA and the available SDSS photometric data. This galaxy demonstrates two tidal tails containing young stellar population, being an extension of its ‘Grand Design’ spiral arms. We obtained the distribution of velocity and oxygen abundance of emission gas (O/H) for two slit orientations. In the central part of the galaxy, a significant role belongs to non-photoionization mechanism of line emission probably caused by shocks due to LINER-like activity of the nucleus. The O/H has a shallow abundance gradient, typical for interacting galaxies. The most intriguing peculiarity of the galaxy is the presence of the discovered earlier huge H i ‘cloud’ containing about half of total mass of galaxy gas, which is strongly displaced outwards and has a velocity exceeding at about 340 $\rm {km~s^{-1}}$ the central velocity of the main galaxy. We found traces of current star formation in the ‘cloud’, even though the cloud is apparently not gravitationally bound with the galaxy. A possible nature of the ‘cloud’ is discussed. We argue that it presents a flow of gas being sweeped by ram pressure and elongated along a line of sight.

A re-examination of pair dynamics and L2 learning opportunities in collaborative writing

Pair dynamics has received much attention in collaborative writing (CW) research. Prior research on the link between pair dynamics and L2 learning opportunities (often operationalized as language related episodes; LREs) in CW has primarily focused on the quantity, length, and outcome of LREs, but rarely considered the quality of the LREs. Also, scarce research has considered the fluctuating nature of pair dynamics and its impact on the L2 learning opportunities. This study employs an approach of detecting pair dynamics that accounts for its fluid nature to investigate how learners’ collaboration in various aspects of CW may influence the quantity, quality, focus, and outcome of the LREs in CW tasks by intermediate L2 learners. Results indicated that while discussion on task management and organization generally took up a limited portion of dyadic interaction, unbalanced contribution to these aspects, especially when coupled with an unequal involvement in content elicitation, greatly affected the quantity and quality of L2 learning opportunities in CW. Also, pairs who participated unequally in discussing language use might still generate many LREs. However, a moderate portion of these LREs represented one learner’s externalized private speech, and thus might not be very beneficial for the other pair member.

The frailty index is associated with the need for care in an aging Swedish population

BackgroundThe Rockwood frailty index (FI) has proven a valid predictor of mortality, institutionalization and requirement for health services. However, little is known about the relationship between the FI and the need for care – an indication of dependency. To this end, we ascertained the associations between the FI and the need for current and future care. MethodsA Rockwood-based FI was tested for association with the current need for care and care needs in the future during a 23-year follow-up in the Swedish Adoption/Twin Study of Aging (n=1477; 623 men, 854 women; aged 29-95 years at baseline). Need for care was defined as receiving help at least once a week in daily routines. Age, sex, education, living alone, smoking status and body mass index were considered as covariates.ResultsThe FI was independently associated with current need for care (OR=1.27 for accumulation of one deficit, 95%CI 1.20–1.34) and future need for care (HR=1.12 for accumulation of one deficit, 95%CI 1.08–1.15). Co-twin control analyses confirmed the results; the pair member currently needing care had higher median FI levels compared to their co-twin not needing care, and the pair member having higher baseline FI had shorter median time to the onset of future care need compared to their co-twin with lower FI.ConclusionsThe FI is a determinant of current care needs and predictive of care needs in the future. The FI may thus represent a risk indicator for dependency and offer an amenable target for preventive measures.

Tooth Root Stresses of Helical Gear Pairs With Unequal and Offset Face Widths

In this study, tooth root stresses of helical gear pairs with different combinations of face width increase and offsets were analyzed. Contact face width was kept constant. The variables studied were face width and gear faces offset. The well-known LDP – Load Distribution Program was used to calculate tooth root stresses using a finite element model. The results presented show that the face width increase and offset have a significant influence on tooth root stresses. In some cases, increasing face width of one gear pair member resulted in significant increase of tooth root stress of the other member. For gear pairs with unequal and offset face widths, tooth root stresses were mostly affected when face widths were increased to the same direction of the contact line travel direction.

Paired-tree study suggests 20-year recurrent slash pine blight

In the late winter of 1988, pairs of slash pine (Pinuselliottii Engelm.) trees were chosen and marked on the Harrison Experimental Forest in Gulfport, Mississippi. One tree of each pair had a blight and the associated fungi Lophodermellacerina Darker on all mature needles, while the other tree had healthy needles. The blight recurred on the same study trees in 1989 and 1990. Analysis of tree cores shows that the blighted member of each pair has had less radial growth than the clean (nonblighted) pair member since about 1971, when a severe needle blight occurred throughout the slash pine region. It appears that the needle blight is causing growth loss and possibly a genetic narrowing of the slash pine resource. The evidence suggests that the most severe occurrence of the blight is near metropolitan areas of the Gulf Coast.

The acquisition of some dimensional adjectives by both normal and language-impaired children

The main aim of this study was to assess various predictions made by H. and E. Clark with respect to the acquisition of certain dimensional adjectives. In addition, the performance of children with impaired language skills was compared with that of children with normally developing language. Eighteen subjects in the age range 3,3 to 4 years were divided into two groups; those with adequate language (C group) and those with impaired language (E group). The dimensional adjective pairs of "length", "tallness" and "width" were investigated on comprehension tasks of increasing dimensionality. A qualitative analysis of the data, for both C and Ε groups, revealed findings supporting the predictions concerning the order of dimensional adjective acquisition in terms of semantic complexity, the acquisition of the unmarked pair member before the marked member, and the acquisition of the concept of polarity before dimensionality. A quantitative analysis of the data revealed significant differences between the C and Ε groups on a few tasks only. Implications for the researcher and speech therapist are considered.

An analysis of seed yield in some strains of subterranean clover (Trifolium subterraneum L.) when grown in binary mixtures

Two experiments using various strains of subterranean clover are described. The first experiment was conducted in the field with mixtures of Dwalganup/Northam A, DwalganupI/Daliak and Yarloop/Seaton Park, and the second in an open-sided glasshouse with Yarloop/Seaton Park. In the field experiment, the plots were grazed continuously from late July until early November when the swards were completely dry; in the glasshouse experiment, the swards were defoliated weekly until shortly after the beginning of flowering. Mixtures were arranged according to the de Wit replacement series. Seed yields for the Dwa1ganup/Northam A mixture showed the classical (de Wit) competition for the same resources, with Northam A the better competitor. On the other hand, for the Dwalganup/Daliak and Yarloop/Seaton Park mixtures there was no clear evidence of a competitive advantage of one strain over the other pair member, at least under our defoliated conditions. Whether or not this absence of 'competition' (as usually understood) is common in clover-strain mixtures is as yet unknown. We emphasize, however, that long-term success of clover strains in mixtures is not invariably associated with competitive advantage.

Persuasiveness and Persuasibility as Related to Intelligence and Emotional Responsiveness

This study was concerned with the contribution of intelligence and emotional responsiveness to persuasiveness and persuasibility of human Ss. Each pair of Ss was required to discuss a topic on which they had initially divergent opinions, with the persuasiveness of one over the other defined as shorter latency of first statement and higher frequency of participation in the discussion, and persuasibility as likelihood of opinion change. Three groups of pairs of Ss were involved. In all groups one member of each pair was high in intelligence and high in emotional responsiveness, with the other pair member low in intelligence and low in emotional responsiveness in the first group, low in intelligence and high in emotional responsiveness in the second group, and high in intelligence and low in emotional responsiveness in the third group. Contrary to expectation, highly intelligent-highly emotionally responsive Ss proved to be less persuasive in all of the groups and more persuasible when paired with Ss of low intelligence and low emotional responsiveness. It was suggested that high emotional responsiveness may have interfered with the adequate expression of high intelligence.