Environment

This chapter introduces the structure and organisation of caravan trade. Focusing on the environment, it opens by connecting the wave of political flux and state-building to the shock of the Little Ice Age, which hit Afro-Eurasia around the mid-seventeenth century. It then sketches the broad geography and circulatory pattern along the north-south routes from the Eurasian interior to the Indian subcontinent. It shows that exchange was based on specialisation and interdependence between the arid zone that stretched from central Asia to the Indo-Afghan frontier and the wet zone of monsoon south Asia, and was subject to seasonal rhythms, with climate shaping when—and through which routes—it was hospitable to pass. It also demonstrates that ecological change—as well as economic and political factors—could shift patterns of specialisation and thereby affect trade, illustrated through a case study of the Indo-central Asian horse trade.

Differential Diagnosis of Malignant Melanoma and Benign Cutaneous Lesions by Ultrasound Analysis

Background: The purpose of the study is to evaluate the assessment of ultrasound analysis in the differential diagnosis of skin melanoma and benign cutaneous lesions. Objective: 61 patients (23 men and 38 women) between 17 and 87 years of age, with melanomas, atheromas, hemangiomas, keratoses, and naevi were studied. Methods: High-frequency gray-scale ultrasound analysis, color Doppler, power Doppler, advanced dynamic flow, strain Elastography, digital Dermoscopy were performed in all cases. Results: In malignant melanoma cases we have mainly: sharp margins, hypoechoic, homogenous structure, absent of posterior shadowing, central and disorganized circulatory pattern with multiple peduncles. In some benign pathology, several ultrasound criteria were exclusive: microcalcifications are only in atheroma, posterior shadowing, and circular rim - in keratosis. The incidence of other ultrasound criteria can vary in atheroma, hemangioma, keratosis, and nevus. Tumor longitudinal and thickness relation were higher (7.9±1.96) than in all benign pathologies (2.1-4.8). The Elastography stiffness of the 26 skin melanomas was 2.95±0.18 and was higher than the group of 35 patients with all benign skin pathology (0.96±0.59), including atheroma (2.0±0.78), hemangioma (0.55±0.21), keratosis (1.21±0.21) and nevus (0.78±0.45). Conclusion: Multimodal approaches to exploring high-frequency ultrasound analytic criteria can be helpful in the differential diagnosis of malignant melanoma and benign cutaneous lesions.

A new species of arboreal rat, genus Oecomys (Rodentia, Cricetidae) from Chaco

A new species of rodent is added to the highly diverse genus Oecomys (Cricetidae, Sigmodontinae, Oryzomyini) based on specimens collected in the Argentinian provinces of Chaco and Formosa. The new species is characterized by a derived carotid circulatory pattern, a feature shared with O. concolor, O. mamorae, and O. sydandersoni. A unique combination of morphological, morphometric, and molecular characters, however, provides unambiguous evidence of its validity as a separate entity. Individuals of the new species are larger than other representatives of Oecomys, and their skulls have wide and cuneate interorbital regions with well-developed supraorbital shelves, long incisive foramina, long palates, absent alisphenoid struts, and broad Eustachian tubes. This new Oecomys appears to be endemic to the Humid Chaco, an ecoregion listed as Vulnerable due to the human impact. Preliminary observations suggest that several specimens from Eastern Paraguay and the Brazilian Pantanal could also be assigned to the new species described herein. Una nueva especie es adicionada al altamente diverso género de roedores Oecomys (Cricetidae, Sigmodontinae, Oryzomyini), sobre la base de especímenes coleccionados en las provincias Argentinas de Chaco y Formosa. La nueva especie se caracteriza por un patrón de circulación carotídea derivado, un rasgo compartido con O. concolor, O. mamorae y O. sydandersoni. Sin embargo, la combinación única de caracteres morfológicos, morfométricos y moleculares provee evidencia inequívoca sobre su validez como una entidad separada. Individuos de la nueva especie son de mayor tamaño en comparación con otros Oecomys y sus cráneos tienen una región interorbitaria ancha y acuñada con plataformas supraorbitarias bien desarrolladas, forámenes incisivos largos, paladares largos, ausencia de las barras alisfenoideas y tubos de Eustaquio anchos. Este nuevo Oecomys parece ser endémico del Chaco Húmedo, una ecorregión considerada como Vulnerable debido al impacto antrópico. Observaciones preliminares sugieren que varios especímenes de Paraguay Oriental y del Pantanal Brasilero podrían también ser asignados a la nueva especie aquí descrita.

Carotid circulatory development in turtles: using existing material to seek critical developmental stages that localize establishment of clade-specific patterns

Recent re-evaluation of variation in the carotid circulation of turtles has revealed that the phylogenetic signal contained in this character complex may indicate different patterns of relationship than have previously been hypothesized. Herein we document cranial circulatory development in Apalone spp. and Chrysemys picta for the first time, with the objective of stimulating future, intensive study of the source of observed circulatory variation in turtles. Both species studied exhibit a nearly identical circulatory pattern, resembling that of adult Trionychia, in later developmental stages. This is an unexpected finding given their highly divergent adult conditions. Further study is required to elucidate the means by which the adult circulatory pattern is attained in these taxa.

Structural and morphological features of Piaractus mesopotamicus (Holmberg, 1887) gills

The pacu Piaractus mesopotamicus (Holmberg, 1887), is a commercially important serrasalmid fish endemic to the Paraná-Paraguay River basin, and one of the most widely cultivated native fish species in the Neotropics. As a migratory species, also inhabiting temporary pools subjected to hypoxic conditions, the species presents a high plasticity concerning respiratory adaptations. In order to supplement basic knowledge on the respiratory physiology and morphology of this species, some structural features of pacu gills, such as filament and lamellae structure, and circulatory pattern are described in this paper.

Improved method for single-bolus kinetic measurements using a noncleared reference indicator

After intravenous injection of a tracer as a single bolus, its concentration decreases as it mixes with the plasma, disperses throughout the circulation, and enters body pools. Kinetic values that are dependent on early concentrations may be in considerable error because mixing is not instantaneous throughout the circulation, and this problem is particularly acute in the mammalian fetus, with its distinctive circulatory pattern. To minimize this error, a method was developed in which the noncleared reference tracer 125I-labeled albumin was injected together with a representative, rapidly cleared metabolite 14C-labeled palmitic acid, and the former was used to correct for mixing delay. A total of 19 disappearance curves were studied after intravenous injection into seven near-term fetal sheep. Kinetic values were calculated with and without correction for mixing delay. Taking account of mixing delay increased the calculated volume of distribution 41% [from 44 +/- 4 (SE) to 62 +/- 3 ml/kg, P < 0.001], increased plasma clearance rate 13% (from 41 +/- 2 to 47 +/- 1 ml-min-1.kg-1, P < 0.002), decreased the rate constant for irreversible loss 26% (from 1.05 +/- 0.07 to 0.78 +/- 0.04 min-1, P < 0.001), and increased the calculated effective half-life 26% (0.71 +/- 0.06 to 0.90 +/- 0.05 min, P < 0.001). Thus use of the additional reference marker significantly altered calculated results and provided values believed to more accurately describe rapid disappearance from the central mixing compartment into metabolic pools.