Cranial Allometry and the Evolution of the Domestic Dog

Domestication is usually defined as a process involving human subjugation of other animal or plant species. From this perspective, it is often presumed that morphological changes in domestic animals are the product of conscious or unconscious human selection. A broader evolutionary perspective does not make this presumption. The origin of the domestic dog (Canis familiaris) is best understood as a consequence of human adoption of wolf pups (Canis lupus) some 12,000 years ago. Young wolf pups growing up in human society formed their primary social bonds with humans. The radically altered circumstances experienced by these early domestic canids placed them in a new role as ecological colonizers. Selection under these circumstances favored precocious maturation, resulting in evolutionary progenesis, a form of heterochrony. Concurrently, an abrupt shift in diet resulted in rapid size reduction in the new evolving species. Craniometric data analyzed from modern wild Canis and prehistoric domesticated dogs from North America and northern Europe, all predating 3,000 B.P. The goal is to assess whether or not morphological changes in dogs are allometric consequences of size reduction, brought about by heterochronic alterations. Previous investigations of canid allometry involving wild canids and modern dog breeds serve as a frame of reference. Bivariate analysis of static data reveals that the dogs exhibit uniquely wide cranial vaults and palates, and are distinct from allometric trends seen among other groups. Anterior cranial length variables are tightly scaled among all groups, with proportional variation a consequence of allometric scaling. Dogs also tend to have proportionally longer teeth than similar sized wild canids. Bivariate analysis of ontogenetic data reveals that wide vaults and palates in dogs are associated with a greater correspondence to wolf ontogenetic regression lines relative to other groups. On anterior cranial length variables all groups exhibit evidence of ontogenetic scaling. Multivariate analysis indicates that dogs are morphologically more similar to juvenile wolves than to any adult group. Juvenilized morphology in dogs is a consequence of rapid size change with morphology constrained to developmental pathways. Invariance in gestation period in Canis may pose a fundamental morphological constraint on dog morphology. Confinement of morphology to developmental boundaries may be indicative of rapid evolutionary change in general. Heterochronic mechanisms responsible for this mode of change may be important in the evolution of domestic animals other and the dog

Paleoeskimo Dogs of the Eastern Arctic

Sled or pack dogs have been perceived as an integral part of traditional life in the Eastern Arctic. This perception stems from our knowledge of the lifeway of recent Thule and modern Inuit peoples, among whom dog sledding has often been an important means of transportation. In contrast, the archaeological record of preceding Paleoeskimo peoples indicates that dogs were sparse at most, and probably locally absent for substantial periods. This pattern is real, not an artifact of taphonomic biases or difficulties in distinguishing dog from wolf remains. Analysis of securely documented dog remains from Paleoeskimo sites in Greenland and Canada underscores the sporadic presence of only small numbers of dogs, at least some of which were eaten. This pattern should be expected. Dogs did not, and could not, assume a conspicuous role in North American Arctic human ecology outside the context of several key features of technology and subsistence production associated with Thule peoples.On a toujours considéré les chiens de traîneau ou chiens de somme comme faisant partie intégrante de la vie traditionnelle dans l'Arctique oriental. Cette perception vient de nos connaissances sur le mode de vie des derniers Thulés et des Inuits modernes, chez qui le traîneau à chiens a souvent représenté un mode de transport majeur. En revanche, les données archéologiques des peuples paléoesquimaux qui ont précédé Thulés et Inuits révèlent que les chiens étaient tout au plus clairsemés, et probablement absents localement pendant de longues périodes. Cette répartition est bien réelle et n'est pas le produit de distorsions taphonomiques ou de difficultés à faire la distinction entre les restes du chien et ceux du loup. L'analyse de restes canins proprement documentés trouvés sur des sites paléoesquimaux au Groenland et au Canada souligne la présence sporadique de chiens en nombre toujours restreint, dont au moins quelques-uns étaient mangés. Cette répartition n'est pas surprenante, les chiens n'assumant pas - et ne pouvant assumer - un rôle évident dans l'écologie humaine de l'Arctique nord-américain en dehors du contexte de diverses caractéristiques clés de la technologie et de la production de subsistance associées aux Thulés

Calorimetric evaluation of 250 AHR Li/SOCl2 cells

Heat generation rates for full size Li/SOCl2 Centaur cells were measured in a conduction calorimeter. Heat capacity measurements were conducted on fresh and discharged cells

Measuring Rights-Based Perspectives: A Validation of the Human Rights Lens in Social Work Scale

Objective: This article reports the initial validation of the Human Rights Lens in Social Work (HRLSW) scale, a tool designed to measure a social worker’s ability to see individual and social problems as resulting from human rights violations. The purpose of the research was to gather evidence regarding the validity of this multidimensional measure of a new construct, i.e., human rights lens. Method: Data from a convenience sample of 1,014 licensed clinical social workers were collected by electronic survey, and the sample was split to conduct discrete exploratory and confirmatory factor analyses. The exploratory factor analysis was performed on half of the sample (n = 507) to establish the underlying factor structure of the construct; the other half of the sample (n = 507) underwent a confirmatory factor analysis to examine the subsample’s psychometric properties. Results: A respecified model using only one error covariance fit the data very well. All fit indices were within their critical values (x2/df ratio = 1.5; CFI =.99; TLI = .99; RMSEA = .03; SRMR = .03). Thus, factor analysis confirms a two-factor, 11-item model for the HRLSW scale, consisting of two subscales, clients seen as experiencing rights violations, and social problems seen as rights violations. Conclusions: This scale is a useful tool for educators, researchers, and practitioners who want to practice—or promote the practice of—social work as a human rights profession

A Conway-Maxwell-Multinomial Distribution for Flexible Modeling of Clustered Categorical Data

Categorical data are often observed as counts resulting from a fixed number of trials in which each trial consists of making one selection from a prespecified set of categories. The multinomial distribution serves as a standard model for such clustered data but assumes that trials are independent and identically distributed. Extensions such as Dirichlet-multinomial and random-clumped multinomial can express positive association, where trials are more likely to result in a common category due to membership in a common cluster. This work considers a Conway-Maxwell-multinomial (CMM) distribution for modeling clustered categorical data exhibiting positively or negatively associated trials. The CMM distribution features a dispersion parameter which allows it to adapt to a range of association levels and includes several recognizable distributions as special cases. We explore properties of CMM, illustrate its flexible characteristics, identify a method to efficiently compute maximum likelihood (ML) estimates, present simulations of small sample properties under ML estimation, and demonstrate the model via several data analysis examples

The significance of glucose, insulin and potassium for immunology and oncology: a new model of immunity

BACKGROUND: A recent development in critical care medicine makes it urgent that research into the effect of hormones on immunity be pursued aggressively. Studies have demonstrated a large reduction in mortality as a result of infusion with glucose, insulin and potassium. Our work in the oncology setting has led us to propose that the principal reason for such an effect is that GIK stimulates lymphocytes to proliferate and attack pathogens, sparing the patient the stress of infection. That suggestion is based on a new model of immunity that describes the effect of hormones on lymphocytes. We hypothesized that the application of glucose, insulin, thyroid and potassium would awaken inert tumor infiltrating lymphocytes to destroy the tumor. METHODS: The antitumor effect of a thyroxine, glucose, insulin, and potassium (TGIK) combination was studied in a series of controlled experiments in murine models of tumor progression to assess the biologic activity of the formulation, the effect of route of administration, the effect on tumor type, and the requirement for insulin in the TGIK formulation. RESULTS: Melanoma and colon tumors inoculated with TGIK were significantly reduced in size or retarded in growth compared to controls injected with saline. I.P. and I.M. injections showed that the formulation had no effect systemically at the doses administered. CONCLUSION: We conclude that TGIK has anti-tumor activity when administered intratumorally, probably by stimulating lymphocytes to attack tumors. This is similar to the effect of GIK on reducing sepsis in critical care patients. We suggest that when GIK is administered exogenously, it restores immune competence to the critically ill or cancer patient and causes destruction of pathogens or tumors, while endogenous resources are devoted to repair. This implies that hormonal therapy may be useful in treating various other pathologies involving immune suppression, as well as malignancies. We also propose research that could bring resolution of the controversy over mechanism and point the way to new therapeutic strategies for numerous diseases including chronic infections and auto-immune diseases

Nanoflows through disordered media: a joint Lattice Boltzmann and Molecular Dynamics investigation

We investigate nanoflows through dilute disordered media by means of joint lattice Boltzmann (LB) and molecular dynamics (MD) simulations -- when the size of the obstacles is comparable to the size of the flowing particles -- for randomly located spheres and for a correlated particle-gel. In both cases at sufficiently low solid fraction, $\Phi<0.01$, LB and MD provide similar values of the permeability. However, for $\Phi > 0.01$, MD shows that molecular size effects lead to a decrease of the permeability, as compared to the Navier-Stokes predictions. For gels, the simulations highlights a surplus of permeability, which can be accommodated within a rescaling of the effective radius of the gel monomers.Comment: 4 pages, 4 figure

Characterisation of cationic amphiphilic cyclodextrins for neuronal delivery of siRNA: effect of reversing primary and secondary face modifications

Significant research is focused on the development of non-viral vectors for delivery of siRNA to neurons and the central nervous system. Cyclodextrins (CDs) have shown great promise as efficient and low toxicity gene delivery vectors in various cell types. Here, we investigate two CDs for siRNA delivery in a neuronal cell model. These CDs were substituted on opposite faces (primary and secondary) with amphiphilic and cationic groups. Physical properties of CD.siRNA complexes, including size, charge and stability were measured. In vitro investigations were carried out in immortalised hypothalamic neurons. Neuronal cell uptake was measured by flow cytometry and cytotoxicity was assessed by MTT assay. Knockdown of a luciferase reporter gene was used as a measure of gene silencing efficiency. Both CDs interacted with siRNA, yielding nanosized cationic complexes which exhibited good stability on storage. A favourable toxicity profile was demonstrated for the CD.siRNA complexes. However, only one of the two CDs mediated high levels of neuronal uptake and efficient gene silencing, equivalent to those achieved with a commercial lipid-based vector. Despite the suitability of both CDs as siRNA delivery vectors in terms of their ability to complex siRNA and the properties of the complexes yielded, only one CD achieved good transfection efficiency. This was likely due to the differences in their chemical structures. The effective CD offers great potential as a novel non-toxic vector for neuronal siRNA delivery

Therapeutic targeting in the silent era: advances in non-viral siRNA delivery

Gene silencing using RNA-interference, first described in mammalian systems almost a decade ago, is revolutionizing therapeutic target validation efforts both in vitro and in vivo. Moreover, the potential for using short interfering RNA (siRNA) as a therapy in its own right is also progressing at a significant pace. However, the widespread use of such approaches is contingent on having appropriate systems to achieve clinically appropriate, safe, and efficient delivery of siRNA. There are many physicochemical and biological barriers to such delivery, and a growing emphasis on the design and characterisation of non-viral technologies that will overcome these barriers and expedite targeted delivery. This review discusses the considerations and challenges associated with use of siRNA-based therapeutics, including stability and off-target effects. Speculation is made on the properties of an ideal delivery system and the non-viral delivery approaches used to date, both in vitro and in vivo, are classified and discussed. Moreover, the ability of cyclodextrin-based delivery vectors to fulfil many of the criteria of an ideal delivery construct is also elaborated