دانلود گزارش کارورزی و کار آموزی

چکیده :

Pseudoreplication (the pooling fallacy) is a widely acknowledged statistical error in the behavioural

sciences. Taking a large number of data points from a small number of animals creates a false impression

of a better representation of the population. Studies of communication may be particularly prone to

artificially inflating the data set in this way, as the unit of interest (the facial expression, the call or the

gesture) is a tempting unit of analysis. Primate communication studies (551) published in scientific

journals from 1960 to 2008 were examined for the simplest form of pseudoreplication (taking more than

one data point from each individual). Of the studies that used inferential statistics, 38% presented at least

one case of pseudoreplicated data. An additional 16% did not provide enough information to rule out

pseudoreplication. Generalized linear mixed models determined that one variable significantly increased

the likelihood of pseudoreplication: using observational methods. Actual sample size (number of animals)

and year of publication were not associated with pseudoreplication. The high prevalence of

pseudoreplication in the primate communication research articles, and the fact that there has been no

decline since key papers warned against pseudoreplication, demonstrates that the problem needs to be

more actively addressed

چکیده : 

The harmful effect of nickel ions released from conventional stainless steel implants has provided a high

level of motivation for the further development of nickel-free stainless steels. In this paper, the microstructure

of medical-grade nickel-free stainless steel powders, with the chemical composition of ASTM

F2581, is studied during mechanical alloying and subsequent annealing. Rietveld X-ray diffraction and

transmission electron microscopy evaluations reflect nanocrystallization, austenitization and amorphization

of the powders due to mechanical activation. It is also realized that annealing of the as-milled powder

can develop a single austenitic structure with nanometric crystallite sizes, implying a considerable

inherent resistance to grain growth. This study demonstrates the merit of mechanical alloying and subsequent

annealing in the development of nanostructured medical-grade stainless steels

چکیده : 

Magnetite nanoparticles have been prepared by electrooxidation of iron in water. Surface modifications

have been conducted by coating the nanoparticles with silica by a one-step synthesis in dilute sodium

silicate solution. The mean size of particles was approximately 10–30 nm for the uncoated particles

and 9–12 nm for the coated particles. The results obtained from thermal gravimetric/differential thermal

analysis (TG/DTA) revealed that the silica layer formed by the electrochemical method was stable and

could serve as a protective layer. Annealing the nanoparticles at 550 C for 30 min converts magnetite

into maghemite for the silica-coated particles, and it further converts the uncoated particles into hematite.

The conversions cause the saturation magnetization to decrease for all samples.

چکیده : 

We present evidence on the 19th-century trend in the height of male US passport

applicants. These men represent a much wealthier segment of contemporary society than

found in most stature samples previously analyzed. The height trend among the wealthy is

much more robust in comparison to the average population that experienced a decline in

stature. The resulting increase in the ‘height gap’—by roughly 1 in. between cohorts born

around 1820 and 1860—is in congruence with evidence on rising wealth inequality and the

notion of dietary change in antebellum America

چکیده : 

The genealogy of the field of anthropometric history has received relatively little scholarly

attention over the years. This paper discusses the contributions to the development of the

field made by sociologist Pitirim A. Sorokin and colleagues in the 1920s and early 1930s. In

so doing, attention is also called to a number of important, but little-utilized

anthropometric sources employed by Sorokin

چکیده : 

Corporate sustainability reporting quality has been frequently criticised as being unbal-anced, presenting an overly positive view or failing to address material issues. The purposeof this article is to provide a fresh explanation for poor quality sustainability reporting andto propose how quality issues may be addressed. The theoretical framework combines thelegitimacy and accountability perspectives using Akerlof’s (1970) Market for Lemons the-ory. Akerlof’s approach is extended by differentiating between three types of informationin sustainability reports namely search, experience and credence. The article concludes thatthe type of information must be considered when determining measures to improve reportquality.