title: PeerJ description: Articles published in PeerJ link: https://peerj.com/articles/index.rss3?journal=peerj&page=1522 creator: info@peerj.com PeerJ errorsTo: info@peerj.com PeerJ language: en title: Occupational health and safety characteristics of agricultural workers in Adana, Turkey: a cross-sectional study link: https://peerj.com/articles/4952 last-modified: 2018-06-01 description: BackgroundAmong agricultural workers, especially in the seasonal migratory ones, housing and hygiene related issues, occupational accidents, low levels of education, poverty and absence of social security problems emerge as significant public health problems. This study aims to compare migrant-seasonal workers (MSWs) and resident agricultural workers (RAWs) in terms of socio-demographic characteristics and occupational health and safety in Adana, one of Turkey’s most important agricultural cities.MethodsThis cross-sectional study was conducted on RAWs and MSWs, aged 15–65, operating in the province of Adana. The calculated sample sizes for both MSWs and RAWs were distributed using stratified simple random sampling to five districts of Adana.ResultsThe mean age of the 798 participating agricultural workers was 34.6 ± 14.2. Of the RAWs, 78.8% and of the MSWs 57.0% were male; 5.8% of RAWs and 32.8% of MSWs were illiterate. The mean number of people in the households of the participating workers was 5.1 for RAWs and 6.6 for MSWs. Of the RAWs, 20.5% were not covered by any social security scheme while this percentage was 35.1% in MSWs. RAWs worked 9.9 h a day while MSWs worked 10.9 h a day. Of the agricultural workers, 12.9% had injuries caused by occupational accidents.DiscussionAgricultural workers, who are a large part of Turkey’s economically active population, do not have healthy and safe working conditions. New regulations in the fields of social security, record keeping, monitoring, supervision, education and occupational health have been implemented recently to solve these problems. Despite the recent improvements there are still some problematic issues in the auditing of the necessary practices. creator: Ramazan Azim Okyay creator: Ferdi Tanır creator: Pelin Mutlu Ağaoğlu uri: https://doi.org/10.7717/peerj.4952 license: http://creativecommons.org/licenses/by/4.0/ rights: © 2018 Okyay et al. title: Understanding the cone scale in Cupressaceae: insights from seed-cone teratology in Glyptostrobus pensilis link: https://peerj.com/articles/4948 last-modified: 2018-06-01 description: Both wild-type and teratological seed cones are described in the monoecious conifer Glyptostrobus pensilis and compared with those of other Cupressaceae sensu lato and other conifers. Some Cupressaceae apparently possess a proliferation of axillary structures in their cone scales. In our interpretation, in Glyptostrobus each bract of both typical and atypical seed cones bears two descending accessory shoots, interpreted here as seed scales (ovuliferous scales). The primary seed scale is fertile and forms the ovules, the second is sterile and forms characteristic tooth-like structures. The bract and the two axillary seed scales are each supplied with a single distinct vascular bundle that enters the cone axis as a separate strand; this vasculature also characterises the descending accessory short shoots in the vegetative parts of the crown. In wild-type seed cones, the fertile seed scale is reduced to its ovules, and the ovules are always axillary. In contrast, the ovules of some of the teratological seed cones examined were located at the centre of the cone scale. An additional tissue found on the upper surface of the sterile lower seed scale is here interpreted as the axis of the fertile seed scale. Thus, the central position of the ovules can be explained by recaulescent fusion of the upper fertile and lower sterile seed scales. In several teratological cone scales, the ovules were enveloped by an additional sterile tissue that is uniseriate and represents an epidermal outgrowth of the fertile seed scale. Close to the ovules, the epidermis was detached from lower tissue and surrounded the ovule completely, except at the micropyle. These teratological features are potentially significant in understanding seed-cone homologies among extant conifers. creator: Veit Martin Dörken creator: Paula J. Rudall uri: https://doi.org/10.7717/peerj.4948 license: http://creativecommons.org/licenses/by/4.0/ rights: © 2018 Dörken and Rudall title: Some maternal lineages of domestic horses may have origins in East Asia revealed with further evidence of mitochondrial genomes and HVR-1 sequences link: https://peerj.com/articles/4896 last-modified: 2018-06-01 description: ObjectivesThere are large populations of indigenous horse (Equus caballus) in China and some other parts of East Asia. However, their matrilineal genetic diversity and origin remained poorly understood. Using a combination of mitochondrial DNA (mtDNA) and hypervariable region (HVR-1) sequences, we aim to investigate the origin of matrilineal inheritance in these domestic horses.MethodsTo investigate patterns of matrilineal inheritance in domestic horses, we conducted a phylogenetic study using 31 de novo mtDNA genomes together with 317 others from the GenBank. In terms of the updated phylogeny, a total of 5,180 horse mitochondrial HVR-1 sequences were analyzed.ResultsEightteen haplogroups (Aw-Rw) were uncovered from the analysis of the whole mitochondrial genomes. Most of which have a divergence time before the earliest domestication of wild horses (about 5,800 years ago) and during the Upper Paleolithic (35–10 KYA). The distribution of some haplogroups shows geographic patterns. The Lw haplogroup contained a significantly higher proportion of European horses than the horses from other regions, while haplogroups Jw, Rw, and some maternal lineages of Cw, have a higher frequency in the horses from East Asia. The 5,180 sequences of horse mitochondrial HVR-1 form nine major haplogroups (A-I). We revealed a corresponding relationship between the haplotypes of HVR-1 and those of whole mitochondrial DNA sequences. The data of the HVR-1 sequences also suggests that Jw, Rw, and some haplotypes of Cw may have originated in East Asia while Lw probably formed in Europe.ConclusionsOur study supports the hypothesis of the multiple origins of the maternal lineage of domestic horses and some maternal lineages of domestic horses may have originated from East Asia. creator: Hongying Ma creator: Yajiang Wu creator: Hai Xiang creator: Yunzhou Yang creator: Min Wang creator: Chunjiang Zhao creator: Changxin Wu uri: https://doi.org/10.7717/peerj.4896 license: http://creativecommons.org/licenses/by/4.0/ rights: ©2018 Ma et al. title: Cranial anatomy of Bellusaurus sui (Dinosauria: Eusauropoda) from the Middle-Late Jurassic Shishugou Formation of northwest China and a review of sauropod cranial ontogeny link: https://peerj.com/articles/4881 last-modified: 2018-06-01 description: Bellusaurus sui is an enigmatic sauropod dinosaur from the Middle-Late Jurassic Shishugou Formation of northwest China. Bellusaurus is known from a monospecific bonebed preserving elements from more than a dozen juvenile individuals, including numerous bones of the skull, providing rare insight into the cranial anatomy of juvenile sauropods. Here, we present a comprehensive description of the cranial anatomy of Bellusaurus, supplementing the holotypic cranial material with additional elements recovered from recent joint Sino-American field expeditions. Bellusaurus is diagnosed by several unique autapomorphies, including a neurovascular foramen piercing the ascending process of the maxilla at midheight, the frontal process of the nasal extending farther posteriorly onto the frontal than the prefrontal, and U-shaped medial and lateral notches in the posterior margin of the ventral process of the squamosal. Several features identified here, including a preantorbital opening in the maxilla, a stepped dorsal margin of the vomerine process of the pterygoid, and the partitioning of the dorsal midline endocranial fossae associated with the dural venous sinuses into anterior and posterior components by a transverse ridge of the parietal, are consistent with recent phylogenetic hypotheses that recover Bellusaurus as a basal macronarian or close relative of Neosauropoda. We review the current state of knowledge of sauropod cranial ontogeny, placing several aspects of the cranial anatomy of Bellusaurus in an ontogenetic context and providing explicit hypotheses of ontogenetic transformations that can be tested by future discoveries of ontogenetic variants of sauropod skulls. While scoring ontogenetically variable characters as unknown may help to alleviate the biasing effects of ontogeny on the phylogenetic position of juvenile specimens, we caution that this approach may remove phylogenetically informative character information, and argue that inference methods that are known to be less sensitive to homoplasy than equal weights parsimony (i.e., implied weights parsimony; Bayesian approaches) should also be employed. creator: Andrew J. Moore creator: Jinyou Mo creator: James M. Clark creator: Xing Xu uri: https://doi.org/10.7717/peerj.4881 license: http://creativecommons.org/licenses/by/4.0/ rights: © 2018 Moore et al. title: Community involvement works where enforcement fails: conservation success through community-based management of Amazon river turtle nests link: https://peerj.com/articles/4856 last-modified: 2018-06-01 description: Law enforcement is widely regarded as a cornerstone to effective natural resource management. Practical guidelines for the optimal use of enforcement measures are lacking particularly in areas protected under sustainable and/or mixed use management regimes and where legal institution are weak. Focusing on the yellow-spotted river turtles (Podocnemis unifilis) along 33 km of river that runs between two sustainable–use reserves in the Brazilian Amazon as an illustrative example, we show that two years of patrols to enforce lawful protection regulations had no effect on nest harvesting. In contrast, during one year when community-based management approaches were enacted harvest levels dropped nearly threefold to a rate (26%) that is likely sufficient for river turtle population recovery. Our findings support previous studies that show how community participation, if appropriately implemented, can facilitate effective natural resource management where law enforcement is limited or ineffective. creator: Darren Norris creator: Fernanda Michalski creator: James P. Gibbs uri: https://doi.org/10.7717/peerj.4856 license: http://creativecommons.org/licenses/by/4.0/ rights: ©2018 Norris et al. title: Phytoregionalisation of the Andean páramo link: https://peerj.com/articles/4786 last-modified: 2018-06-01 description: BackgroundThe páramo is a high-elevation biogeographical province in the northern Andes, known for its great biodiversity and ecosystem services. Because there have been very few biogeographic studies encompassing the entire province to date, this study aimed at conducting a phytogeographical regionalisation of the páramo. Specifically, (1) clustering analyses were conducted to identify the main phytogeographical units in the three altitudinal belts: sub-páramo, mid-páramo and super-páramo, and examine their diagnostic flora, (2) an ordination complemented the geo-climatic characterization of the obtained units and (3) a hierarchical classification transformation was obtained to evaluate the relationships between units.MethodsThe study area included the entire Andean páramo range in northern Peru, Ecuador, Colombia and Venezuela. The analyses were based on 1,647 phytosociological plots from the VegPáramo database. The K-means non-hierarchical clustering technique was used to obtain clusters identifiable as phytogeographical units, and the Ochiai fidelity index was calculated to identify their diagnostic species. A principal component analysis was conducted to obtain the geo-climatic characterization of each unit. Finally, the relationships between clusters were traced using a hierarchical plot-based classification.ResultsFifteen clusters were obtained, 13 natural and two artificial, of which two represented the sub-páramo, nine the mid-páramo and four the super-páramo. Even though data representativeness was a potential limitation to segregate certain sub-páramo and super-páramo units, the overall bioregionalisation was robust and represented important latitudinal, altitudinal and climatic gradients.DiscussionThis study is the first to bioregionalise the páramo province based on a substantial widely distributed biological dataset, and therefore provides important novel scientific insight on its biogeography. The obtained phytogeographical units can be used to support further research on the páramo at smaller scale and on the humid Neotropical high-elevation ecosystems at broader-scale. Finally, several units were highlighted in our results as particularly worthy of further scientific and conservation focus. creator: Gwendolyn Peyre creator: Henrik Balslev creator: Xavier Font uri: https://doi.org/10.7717/peerj.4786 license: http://creativecommons.org/licenses/by/4.0/ rights: © 2018 Peyre et al. title: Comparing the biomechanical characteristics between squat and standing serves in female table tennis athletes link: https://peerj.com/articles/4760 last-modified: 2018-06-01 description: BackgroundThe table tennis serve involves complex spatial movements combined with biomechanial characteristics. Although the differences in lower-limb biomechanial characteristics to a great extent influence the translational and spinning velocity of the ball when using the different styles of table tennis serve, few researchers have studied their mechanics. Therefore, the aim of this study was to investigate the differences in lower-limb activity between the squat and standing serves during a table tennis short serve.MethodsTen advanced female table tennis participants performed a squat serve and standing serve in random order. A Vicon motion analysis system and a Novel Pedar insole plantar pressure measurement system were used to record kinematics and kinetics data, respectively.ResultsKey findings from the study were that the squat serve not only showed significantly larger hip and knee flexion, as well as ankle dorsiflexion, it also showed significantly larger hip adduction and external knee rotation, with larger changing angular rate of the lower limb joints in the sagittal and the transverse planes when the two serving styles were compared. In addition, the force-time integral (FTI) was higher in the rear foot area for the standing serve.DiscussionThe results demonstrated that the squat serve needs higher lower limb drive during a table tennis short serve compared with a standing serve. These biomechanical considerations may be beneficial for table tennis athletes and coaches as a method of optimizing performance characteristics during both competition and training. creator: Changxiao Yu creator: Shirui Shao creator: Julien S. Baker creator: Yaodong Gu uri: https://doi.org/10.7717/peerj.4760 license: http://creativecommons.org/licenses/by/4.0/ rights: ©2018 Yu et al. title: Sexually dimorphic venom proteins in long-jawed orb-weaving spiders (Tetragnatha) comprise novel gene families link: https://peerj.com/articles/4691 last-modified: 2018-06-01 description: Venom has been associated with the ecological success of many groups of organisms, most notably reptiles, gastropods, and arachnids. In some cases, diversification has been directly linked to tailoring of venoms for dietary specialization. Spiders in particular are known for their diverse venoms and wide range of predatory behaviors, although there is much to learn about scales of variation in venom composition and function. The current study focuses on venom characteristics in different sexes within a species of spider. We chose the genus Tetragnatha (Tetragnathidae) because of its unusual courtship behavior involving interlocking of the venom delivering chelicerae (i.e., the jaws), and several species in the genus are already known to have sexually dimorphic venoms. Here, we use transcriptome and proteome analyses to identify venom components that are dimorphic in Tetragnatha versicolor. We present cDNA sequences including unique, male-specific high molecular weight proteins that have remote, if any, detectable similarity to known venom components in spiders or other venomous lineages and have no detectable homologs in existing databases. While the function of these proteins is not known, their presence in association with the cheliceral locking mechanism during mating together with the presence of prolonged male-male mating attempts in a related, cheliceral-locking species (Doryonychus raptor) lacking the dimorphism suggests potential for a role in sexual communication. creator: Pamela A. Zobel-Thropp creator: Emily A. Bulger creator: Matthew H.J. Cordes creator: Greta J. Binford creator: Rosemary G. Gillespie creator: Michael S. Brewer uri: https://doi.org/10.7717/peerj.4691 license: http://creativecommons.org/licenses/by/4.0/ rights: ©2018 Zobel-Thropp et al. title: Cytotoxic effects of zinc oxide nanoparticles on cyanobacterium Spirulina (Arthrospira) platensis link: https://peerj.com/articles/4682 last-modified: 2018-06-01 description: BackgroundThe extensive usage of zinc oxide nanoparticles (ZnO NPs) in industrial and consumer products raises the risk of releasing their residues into the aquatic environment. The presence of ZnO NPs in the aquatic environment could potentially cause cytotoxic effects on aquatic organisms. Thus, investigating the cytotoxic effects of ZnO NPs on microalgae, which form the base for the food web of aquatic biota, is essential to gain information regarding the ecotoxicological effects of metallic oxide nanoparticles in the aquatic ecosystem. Therefore, the present study has investigated in detail the assorted cytotoxic effects of ZnO NPs on S. platensis using various concentrations of ZnO NPs (10–200 mg/L) from 6 to 96 h to explore the dose- and time-dependent cytotoxic effects.MethodsThe cytotoxic effects were all assessed through quantification of loss in cell viability, reduction in biomass and decrease in photosynthetic pigments such as chlorophyll-a, carotenoids and phycocyanin. The surface interactions of nanoparticles and the subsequent morphological alterations on algal cells were examined by optical and scanning electron microscopy (SEM). The intracellular alterations of algal cells were studied using transmission electron microscopy. Furthermore, Fourier transformed infrared (FTIR) spectrum was obtained to investigate the involvement of algal surface biomolecules in surface binding of ZnO NPs on algal cells.ResultsThe treatment of ZnO NPs on S. platensis exhibited a typical concentration- and time-dependent cytotoxicity. Results showed a significant (p < 0.05) cytotoxicity from 24 h onwards for all tested concentrations of ZnO NPs. The maximum cytotoxicity on algal cells was achieved at 96 h of exposure to ZnO NPs. In comparison with control, the algal cells that interacted with 200 mg/L of ZnO NPs for 96 h showed 87.3 ± 1% loss in cell viability, 76.1 ± 1.7% reduction in algal biomass, 92.5 ± 2.2%, 76.2 ± 2.2% and 74.1 ± 3.4% decrease in chlorophyll-a, carotenoids and phycocyanin contents respectively. Our study confirmed the cytotoxicity of ZnO NPs through the algal growth inhibition with 72 h EC10 and EC50 values of 1.29 and 31.56 mg/L, respectively. The microscopic examinations of the algal cells that interacted with ZnO NPs showed severe cell membrane and intracellular damage. The SEM EDX spectrum of ZnO NPs treated algal biomass evidenced the surface accumulation of zinc in the biomass. Finally, the FTIR spectrum confirmed the involvement of amino, hydroxyl and carboxylic groups of algal cell wall in the surface interaction of ZnO NPs on the algal cells.DiscussionThe results showed that the treatment of ZnO NPs on S. platensis triggered substantial cytotoxicity and caused cell death. Hence, S. platensis could be potentially used as a bioindicator for testing toxicity of ZnO NPs in aquatic environment. creator: Sinouvassane Djearamane creator: Yang Mooi Lim creator: Ling Shing Wong creator: Poh Foong Lee uri: https://doi.org/10.7717/peerj.4682 license: http://creativecommons.org/licenses/by/4.0/ rights: ©2018 Djearamane et al. title: Assessing canalisation of intraspecific variation on a macroevolutionary scale: the case of crinoid arms through the Phanerozoic link: https://peerj.com/articles/4899 last-modified: 2018-05-31 description: Clades that represent a new ‘Bauplan’ have been hypothesised to exhibit more variability than more derived clades. Accordingly, there is an expectation of greater variation around the time of the origin of a clade than later in its evolutionary history. This ‘canalisation’ has been tested in terms of morphological disparity (interspecific variation), whereas intraspecific variation in macroevolution is rarely studied. We analysed extensive data of brachial counts in crinoid populations from the Ordovician to the Recent to test for canalisation in morphological intraspecific variation. Our results show no support for the canalisation hypothesis through the Phanerozoic. This lack of pattern is maintained even when considering crinoid subclades separately. Our study is an example of the lack of universality in such macroevolutionary patterns both in terms of organisms and in terms of modules within them. It is also an example on the challenges and limitations of palaeontological studies of macroevolutionary processes. creator: Catalina Pimiento creator: Kit Lam Tang creator: Samuel Zamora creator: Christian Klug creator: Marcelo R. Sánchez-Villagra uri: https://doi.org/10.7717/peerj.4899 license: http://creativecommons.org/licenses/by/4.0/ rights: ©2018 Pimiento et al.