Multivariate analysis of cranial measurements of Cameroon’s Blue Duiker (Cephalophusmonticola Thunberg, 1789)

The blue duiker (Cephalophusmonticola)isexclusively an African wild bovidae. It is a principal source of protein in the African forest zones and contributes in the nutrition of local populations. Fifteen cranial measurements on 60 skulls using the opportunist’s method as from January 2018 to December2018. Descriptive statistic and multivariate analysis were done using SPSS version 21.0software and XLSTAT-Pro version 7.5.2 software. It reveals that, there exist a significant difference between males and females skull (p>0.05): total length of skull 114.32 ± .81 and 121.71 ± 1.77; Palate maximal width 35.24 ± .75 and 44.96 ± 14.80; postorbital apophyses width 23.34 ± 1.11and 36.26 ± 1.79; Palatine length 55.31 ± 1.16 and 66.52 ± 1.86; condyle basal length 96.53 ± 1.26 and 105.43 ± 3.05 for the males and females respectively. We have a high positive correlation between the jugal teeth line length and the total skull length (0.973); between palatine length and the total skull length (0.990) and, between condyle basal length and the total skull length (0.993). The principal component analysis (PCA) enable us to see the level of genetics variabilities of blue duiker through skull measurements. These variables measurement are close together from one to another where there is a high similarity between species. Despite these similarities, the population structure of blue duiker shows three sub-species of blue duiker C1, C2 and C3 found respectively in the agro ecological zones of the Western highlands, Mono-modal humid forest and Bimodal humid forest. These three sub-species varies genetically.

An exceptionally preserved armored dinosaur reveals the morphology and allometry of osteoderms and their horny epidermal coverings

Although the evolution and function of “exaggerated” bony projections in ornithischian dinosaurs has been subject to significant debate recently, our understanding of the structure and morphology of their epidermal keratinized coverings is greatly limited. The holotype ofBorealopelta, a new nodosaurid ankylosaur, preserves osteoderms and extensive epidermal structures (dark organic residues), in anatomic position across the entire precaudal length. Contrasting previous specimens, organic epiosteodermal scales, often in the form of horn-like (keratinous) sheaths, cap and exaggerate nearly all osteoderms, allowing for morphometric and allometric analyses of both the bony osteoderms and their horny sheaths. A total of 172 osteoderms were quantified, with osteoderm spine length and height being positively allometric with respect to basal length and width. Despite tight correlations between the different measures amongst all other osteoderms, the large parascapular spines represent consistent outliers. Thickness and relative contribution of the keratinized epiosteodermal scales/sheaths varies greatly by region, ranging from 2% to 6% for posterior thoracics, to ∼25% (1.3×) for the parascapular spines—similar to horn sheaths in some bovid analogues. Relative to the bony cores, the horny portions of the spines are strongly positively allometric (slope = 2.3, CI = 1.8–2.8). Strong allometric scaling, species-specific morphology, and significant keratinous extension of the cervicoscapular spines is consistent with elaboration under socio-sexual selection. This marks the first allometric analysis of ornithischian soft tissues.

Tunable supercapacitor performance of potentiodynamically deposited urea-doped cobalt hydroxide

The influence of the basal length of Co(OH)2 on supercapacitor performance was examined in detail by adding simple urea molecules during deposition. It was observed that the specific capacitance of Co(OH)2 could be tuned from 700 to 1200 F g−1. This high specific capacitance was attributed to the better access of electrolyte.

Kinetics of platelet adhesion and thrombus growth

Epifluorescent microscopy was used to monitor the adhesion of platelets and the growth of platelet aggregates on collagen-coated glass tubes perfused with whole blood. The maximum basal length and width of the aggregate size increased linearly with time, growing symmetrically transverse to the direction of flow and asymmetrically in the plane longitudinal to the direction of flow. Aggregates had elliptical bases, with the major axis parallel to the direction of blood flow. These studies provide an experimental approach to studies of the kinetics of platelet interaction with artificial surfaces and give further support to the concept that blood flow has a major effect on the development of platelet thrombi.

Kinetics of platelet adhesion and thrombus growth

Epifluorescent microscopy was used to monitor the adhesion of platelets and the growth of platelet aggregates on collagen-coated glass tubes perfused with whole blood. The maximum basal length and width of the aggregate size increased linearly with time, growing symmetrically transverse to the direction of flow and asymmetrically in the plane longitudinal to the direction of flow. Aggregates had elliptical bases, with the major axis parallel to the direction of blood flow. These studies provide an experimental approach to studies of the kinetics of platelet interaction with artificial surfaces and give further support to the concept that blood flow has a major effect on the development of platelet thrombi.

Notes on the Biology of Cirripedes

In the course of some 4 years′ work on the biology of fouling organisms, observations have been made on aspects of the general biology of Balanus balanoides, B. crenatus and Verruca stroemia.Observations on the state of development of the ova within the mantle cavity of B. balanoides and of the occurrence of the larvae in the plankton indicate that hatching takes place during the first fortnight in March, that the later-stage nauplii are abundant during the second half of that month and that the cyprid larvae may become abundant during April. The larval sequence is not always completed successfully; conditions which seem inimical are discussed.Factors which seem to be of importance in affecting settlement of B. balanoides are discussed. The presence of other organisms is an adverse factor, though the potency of this factor is probably not the same for all organisms; the presence of slime can prevent settlement and, though evidence can be quoted in support of heavier settlement on shaded surfaces, it is emphasized that the operation of other factors may have brought about this result. The proportion of the tidal cycle during which current speeds are not too high to prevent settlement seems likely to be important.Provided that other conditions are favourable B. balanoides settles readily on surfaces continuously immersed and individuals which settle under these conditions grow more rapidly, at least for the first few months after settlement, than their contemporaries on the shore.The larvae of B. crenatus appear in the plankton rather earlier than those of B. balanoides, but the time taken to complete the larval sequence from the 1st stage nauplius to the cyprid is roughly the same as that for the latter species, namely 1 month. In B. crenatus, however, hatching is not limited to a short period during March but continues at intervals through the summer. There are indications that the successful completion of the larval sequence of this species is less affected by an abundance of phytoplankton than is that of B. balanoides.Settlement of B. crenatus is periodic and individuals which settle early in the spring can attain practically their full size (28–30 mm. basal length) during the same season. Growth during the summer takes place at average rates which vary from 0·1 to 0·2 mm. increase in basal length per day. Growth is negligible during the winter months.Specimens of B. crenatus which settle early in April contain developing ova by the beginning of July, so that spring-settled forms can produce larvae which themselves may settle before the end of the summer.Observations on Verruca stroemia have been limited to the occurrence of the larvae in the plankton. Like those of Balanus crenatus, the larvae of Verruca stroemia are present at intervals through the summer. Early-stage nauplii of this species may dominate the plankton early in the year, but no correspondingly heavy hauls of later-stage nauplii have been recorded. Possible explanations of this discrepancy are discussed. The cyprid never occurs in any numbers in surface hauls.Incidental observations on the planktonic occurrence of the nauplii of Sacculina (probably S. carcini) and of Peltogaster paguri are given.Details are given of the abundance of all Cirripede larvae in the plankton for the years 1944–47 which emphasize the extent of variation that can occur from year to year.