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Some animals have evolved task differentiation among their eyes. A particular example is spiders, where most species have eight eyes, of which two (the principal eyes) are used for object discrimination, whereas the other three pairs (secondary eyes) detect movement. In the ctenid spider Cupiennius salei, these two eye types correspond to two visual pathways in the brain. Each eye is associated with its own first- and second-order visual neuropil. The second-order neuropils of the principal eyes are connected to the arcuate body, whereas the second-order neuropils of the secondary eyes are linked to the mushroom body. We explored the principal- and secondary eye visual pathways of the jumping spider Marpissa muscosa, in which size and visual fields of the two eye types are considerably different. We found that the connectivity of the principal eye pathway is the same as in C. salei, while there are differences in the secondary eye pathways. In M. muscosa, all secondary eyes are connected to their own first-order visual neuropils. The first-order visual neuropils of the anterior lateral and posterior lateral eyes are connected with a second-order visual neuropil each and an additional shared one (L2). In the posterior median eyes, the axons of their first-order visual neuropils project directly to the arcuate body, suggesting that the posterior median eyes do not detect movement. The L2 might function as an upstream integration center enabling faster movement decisions.

Background The surgical approaches remain controversial for the treatment of middle and distal-third humeral shaft (MDTHS) fractures. This study compared clinical effects of the anterolateral approach with two incisions (AATI) and the posterior median approach (PMA) in the treatment of MDTHS fractures. Methods A retrospective analysis was carried out. One hundred sixty-six patients with MDTHS fractures were selected from January 2015 to January 2017 in Xi’an Hong Hui Hospital. According to surgical approaches, patients were divided into AATI (86 cases) and PMA group (80 cases). All patients were treated with open reduction and plate fixation. Operation indexes were compared, including incision length, operation time, and bleeding. Bryan-Morrey score was used to evaluate elbow joint function. Complication incidence was compared, such as incision infection, iatrogenic radial nerve injury, and nonunion. Results The AATI group showed smaller incision length, less bleeding, lower iatrogenic radial nerve injury rate, and better elbow function than that of PMA group (P Conclusions The middle and distal-third humeral shaft fractures can be successfully cured by both approaches. Compared with the posterior median approach, it has better clinical effects of the anterolateral approach with two incisions, which is worthy of clinical application and promotion.

A new genus and three new species of the spider family Palpimanidae Thorell, 1870 from Kenya are described. Sceliscelis Oketch & Li, gen. nov. is close to Sarascelis Simon, 1887 and Scelidocteus Simon, 1907 but differs in the structure of the male palp. The new species reported are Sceliscelis marshi Oketch & Li, sp. nov., Scelidocteus taitave Oketch & Li, sp. nov., and Hybosida machondogo Oketch & Li, sp. nov.Sceliscelis marshisp. nov. is described from males and females collected from Tsavo in south Kenya. Scelidocteus taitavesp. nov. can be distinguished from other congeners, as well as from the morphologically similar Scelidomachus socotranus Pocock, 1899, by the shape of the palpal “conductor”. Hybosida machondogosp. nov. differs from other six-eyed Hybosida spp. by possessing rudimentary posterior median eyes.

Cylindrical silk gland (CY) spigots distinguish a large clade of modern spiders, the CY spigot clade, which includes all entelegyne spiders and their closest relatives. Following a widespread paradigm, CYs and their spigots are only known to occur in female spiders and they produce silk used in the construction of egg sacs. Here we report the occurrence of a CY spigot or CY nubbin on each posterior median spinneret (PMS) in males (5th stadium and later) of the spider Australomimetus maculosus. Late juvenile males had a CY spigot on each PMS, whereas adult males either had a CY spigot or, more often, a non-functional CY nubbin. This indicates that potential CY use by males is at least largely limited to late juvenile instars and is not involved with egg sac construction. Despite the presence of CY spigots in both sexes, sexual dimorphism with respect to CYs was still evident since males lacked the CY spigot on each posterior lateral spinneret present in late juvenile and adult females, and CY spigots of males never had the wide shaft and opening of adult females. This study adds to our knowledge of spinning apparatus variability in modern spiders and demonstrates an exception to the paradigm that, in the CY spigot clade, such spigots are restricted to female spiders.

Stable isotope mixing models (SIMMs) provide a powerful methodology for quantifying relative contributions of several sources to a mixture. They are widely used in the fields of ecology, geology, and archaeology. Although SIMMs have been rapidly evolved in the Bayesian framework, the underdetermination of mixing space remains problematic, i.e., the estimated relative contributions are incompletely identifiable. Here we propose a statistical method to quantitatively diagnose underdetermination in Bayesian SIMMs, and demonstrate the applications of our method (named β-dependent SIMM) using two motivated examples. Using a simulation example, we showed that the proposed method can rigorously quantify the expected underdetermination (i.e., intervals of β-dependent posterior) of relative contributions. Moreover, the application to the published field data highlighted two problematic aspects of the underdetermination: 1) ordinary SIMMs was difficult to quantify underdetermination of each source, and 2) the marginal posterior median was not necessarily consistent with the joint posterior peak in the case of underdetermination. Our study theoretically and numerically confirmed that β-dependent SIMMs provide a useful diagnostic tool for the underdetermined mixing problem. In addition to ordinary SIMMs, we recommend reporting the results of β-dependent SIMMs to obtain a biologically feasible and sound interpretation from stable isotope data.

Despite the recognition of spider silk as a biological super-material and its dominant role in various aspects of a spider&rsquo, s life, knowledge on silk use and silk properties is incomplete. This is a major impediment for the general understanding of spider ecology, spider silk evolution and biomaterial prospecting. In particular, the biological role of different types of silk glands is largely unexplored. Here, I report the results from a comparative study of spinneret usage during silk anchor and dragline spinning. I found that the use of both anterior lateral spinnerets (ALS) and posterior median spinnerets (PMS) is the plesiomorphic state of silk anchor and dragline spinning in the Araneomorphae, with transitions to ALS-only use in the Araneoidea and some smaller lineages scattered across the spider tree of life. Opposing the reduction to using a single spinneret pair, few taxa have switched to using all ALS, PMS and the posterior lateral spinnerets (PLS) for silk anchor and dragline formation. Silk fibres from the used spinnerets (major ampullate, minor ampullate and aciniform silk) were generally bundled in draglines after the completion of silk anchor spinning. Araneoid spiders were highly distinct from most other spiders in their draglines, being composed of major ampullate silk only. This indicates that major ampullate silk properties reported from comparative measurements of draglines should be handled with care. These observations call for a closer investigation of the function of different silk glands in spiders.

In neuroanatomy textbooks on humans, the posterior median septum is commonly depicted along the midline of the posterior column of the spinal cord. For intramedullary spinal cord tumors, the standard surgical treatment is posterior midline myelotomy. However, its anatomical basis is still unclear. Therefore, in this study we focused on the ultrastructural characterization of the median structure of the posterior column in an adult rat. In the median part of the fasciculi gracilis, a fine lineal tissue continued from the posterior median sulcus to the 3/4th depth of the fasciculi. At higher magnification, this fine lineal tissue consisted of bundles of astrocytes, which are often disrupted and eventually disappeared. At the junction of the ventral part of the fasciculi cuneatus and the gray commissure, short lineal figures of glial tissues extended dorsally. These lineal figures of glial tissues were morphologically similar to other lineal figures of glial tissues found in the posterior column; bundles of astrocytes extending along the axons that entered the gray commissure and the perivascular lineal figures of glial tissues. In conclusion, this study revealed that the posterior median septum is composed of very fine lineal figures of glial tissues that are often disrupted and eventually disappear. We consider these basic structures to be similar in humans. Therefore, during posterior midline myelotomy, accurately separating along the posterior median septum in the posterior column is extremely difficult.

Pseudonemesia tabiskey sp. nov. is described from an Andean Forest in Trujillo, Venezuela. The new species is the third for the genus and differs from the other two species by the presence of one short and apically rounded modified seta on the retrolateral distal portion of the male tibia I and clavate setae on the dorsal and lateral sides of abdomen in both sexes. A new diagnosis is given to Pseudonemesia and new morphological data based on scanning electron microscopy for the Microstigmatinae are presented. The presence of posterior median spinnerets in Pseudonemesia is discussed.

Agelenidae is a species rich and globally-distributed spider family comprising 1274 species in 77 genera (World Spider Catalog 2018). In Iran, this family is currently represented by eight species in four genera (Zamani et al. 2018). Being the second largest genus of the family (after Draconarius Ovtchinnikov, 1999), Tegenaria Latreille, 1804, currently encompasses 105 species that are primarily distributed in the Palaearctic (World Spider Catalog 2018; Marusik & Zamani 2015). So far, four species of this genus are known from Iran: Tegenaria domestica (Clerck, 1758) (western, northern, central and eastern Iran), T. lenkoranica (Guseinov et al., 2005) (northern Iran), T. pagana C.L. Koch, 1840 (northern Iran), and the endemic T. zamanii Marusik et Omelko, 2014 (northern Iran) (Zamani et al. 2018). Two of these species, T. lenkoranica and T. zamanii have been reported from caves (Malek-Hosseini & Zamani 2017). Considering the lack of studies on this genus in Iran, many species are undoubtedly awaiting to be discovered. During the biospeleological investigations of Zagros Mountains, a new species of Tegenaria was collected in western Iran, which is described and illustrated in this paper. The specimens were photographed using an Olympus Camedia E-520 camera attached to an Olympus SZX16 stereomicroscope and digital images were prepared using “CombineZP” image stacking software. Leg ratios were measured on the dorsal side and all measurements are given in millimeters. Measurements of leg are listed as: total length (femur, patella, tibia, metatarsus, tarsus). Standard abbreviations were used for the eyes: AME, anterior median eyes; ALE, anterior lateral eyes; PME, posterior median eyes; PLE, posterior lateral eyes. The specimens will be deposited in the Manchester Museum of the University of Manchester (MMUE).

The authors report simultaneous surgical treatment of the right S1 root schwannoma with extravertebral retroperitoneal spread. Well-equipped operating theatre, professional experience and multidisciplinary approach involving neurosurgeons and abdominal surgeons ensure total minimally invasive simultaneous resection of schwannoma via posterior median and laparoscopic approach.Представлено клиническое наблюдение симультанного оперативного лечения невриномы правого спинномозгового корешка S1 с экстравертебральным ретроперитонеальным распространением. Операционная, полностью оснащенная современным хирургическим оборудованием, профессиональный опыт и мультидисциплинарный подход к лечению у нейрохирургов и абдоминальных хирургов позволили выполнить радикальное, минимально инвазивное одномоментное удаление образования из заднего срединного и лапароскопического доступа.

Although associated with a higher approach-related traumatic impact on the soft tissue of the neck than the anterior approach, the posterior median approach to the subaxial cervical spine remains standard for numerous indications. Reported procedure-related complications in posterior cervical surgical interventions can be significantly reduced by appropriate preoperative planning and patient positioning as also by a straightforward surgical approach technique and wound closure. Inadvertence during dissection leads to higher blood loss and extended surgical time; has a collateral impact on clinical outcomes, infection and revision rates; and might lead to adjacent segment degeneration and instability. Thus, the aim of the article is to present technical nuances and tips for complication avoidance related to the posterior median access to the subaxial spine.

A hydrologic uncertainty processor (HUP) that the prior density and likelihood function are explicitly expressed is introduced based on a copula function. The results show that the copula-based HUP is comparable to the meta-Gaussian HUP regarding the posterior median forecasts. Besides, the probabilistic forecasts produced by the copula-based HUP have slightly higher reliability and lower resolution, as compared to those of the meta-Gaussian HUP. A Copula Bayesian processor associated with the Bayesian model averaging (CBP-BMA) method is used with ensemble lumped hydrological models. Compared with the BMA and Copula-BMA methods, the CBP-BMA method relaxes any assumption on the distribution of conditional PDFs. The case study results demonstrate that the CBP-BMA method can improve hydrological forecasting precision with higher coverage ratios. The copula-based HUP and CBP-BMA methods provide alternative approaches to uncertainty analysis of hydrological forecasts.

The Neotropical Sasoninae Neodiplothele Mello-Leitão, 1917 is revised and now includes eight species. Neodiplothele can be distinguished from other Sasoninae by the absence of the posterior median spinnerets and differs Neotropical relatives as Cosmopelma by the absence of cuspules on coxae of leg I and Paracenobiopelma by the absence of cuspules on the labium. The male of N. irregularis Mello-Leitão, 1917 and N. picta Vellard, 1924 are described and illustrated for the first time. Neodiplothele leonardosi Mello-Leitão, 1939 is considered a junior synonym of N. irregularis. Five new species are described from Brazil: N. aureus sp. nov. from the states of Ceará, Rio Grande do Norte, Paraíba, and Minas Gerais, N. itabaiana sp. nov. from Sergipe, N. martinsi sp. nov. from Bahia, Espírito Santo, and Minas Gerais, N. indicattii sp. nov. from Espírito Santo, Minas Gerais, Rio de Janeiro, and São Paulo, N. caucaia sp. nov. from Ceará, Goiás, and Mato Grosso do Sul. Two informal groups are proposed based on genitalia morphology: irregularis group and picta group. An identification key and new distribution records for all known species are given.

Roughly half of Bayes’s famous essay was written by Richard Price, including the Appendix with all of the numerical examples. A study of this Appendix reveals Price (1) unusually for the time, felt it necessary to allow in his analysis for a hypothesis having been suggested by the same data used in its analysis, (2) was motivated (covertly in 1763, overtly in 1767) to undertake the study to refute David Hume on miracles, and (3) displayed a remarkable sense of collegiality in scientific controversy that should stand as a model for the present day. Price’s analysis of the posterior in one particular example, including locating the posterior median and giving and interpreting credible regions, qualifies him as the first person to apply Bayes’s theory.

Background Species of Diplozoon Palombi, 1949 (Monogenea: Diplozoidae) are blood-feeding ectoparasites mainly parasitising the gills of cyprinid fishes. Although these parasites have been the subject of numerous taxonomic, phylogenetic and ecological studies, the ultrastructure of the surface and haptor attachment structures remains almost unknown. In this study, we used transmission electron microscopy to examine the ultrastructure of attachment clamps and neodermal surface of Paradiplozoon homoion (Bychowsky & Nagibina, 1959), family Diplozoidae Palombi, 1949, thereby broadening our knowledge of platyhelminth biology. Results The hindbody surface of P. homoion is distinctly ridged, each ridge being supported by several muscle fibers and equipped with scales on the surface plasma membrane. Such structures have not been recorded previously in species of the family Diplozoidae. Comparisons of the surface structure of different body parts revealed slight differences in the thickness and number of organelles. Each of the clamps has a flattened bowl-like structure composed of sclerites, movable skeletal-like structures that are anchored by robust, radially oriented muscle bundles. The base of the posterior median plate sclerites is equipped with glandular cells possessing secretory vesicles. Conclusion This study brings detailed ultrastructural data for the surface and haptoral attachment clamps of P. homoion and provides new insights into the ultrastructure of Diplozoidae. Glandular cells at the base of the attachment clamps responsible for sclerite development in diplozoid species were observed for the first time. Our findings support the hypothesis that the structure of particular neodermal compartments is similar within the Platyhelminthes. On the other hand, the diplozoid glandular system and the mechanism of sclerite development clearly merits further attention.

The wolf spider Lycosa tarantula returns home by means of path integration. Previous studies demonstrated: (i) that the angular component of the outbound run is measured using a polarized-light compass associated with the anterior median eyes; (ii) changes in direction of the substratum are detected by the anterior lateral eyes (ALEs); and (iii) in relation to the linear component of the outbound run, an increase of optic flow, in either the lateral or ventral fields of view, caused spiders to search for the burrow at a point nearer to the goal. However, the role of the secondary eyes [ALEs, posterior lateral eyes (PLEs) and posterior median eyes (PMEs)] in the perception of this optic flow and the importance of them for gauging the distance walked is still unknown. In this study, lateral or ventral gratings of wavelength λ=1 cm were used, with two groups of spiders in each setup: (1) PLEs+PMEs covered and (2) ALEs covered. The largest reduction in the distance walked to return to the burrow was observed with the ventral grating/ALEs covered. These results show the importance of the previously neglected ALEs for the visual behavior of these spiders. The possibility of gathering information for locomotion from the three pairs of secondary eyes in the mushroom bodies is discussed.