PURPOSE The purpose of this study was to investigate and report on a new intraoperative measuring technique to place the anterior cruciate ligament (ACL) femoral tunnel in the center of the native ACL femoral insertion site. METHODS We investigated a novel measuring technique based on identifying the proximal border of the articular cartilage and using a specific ruler parallel to the femoral...

OBJECTIVE Despite the current use of radiography for quantifying sagittal skeletal measurements, it is an unsuitable way for screening or epidemiologic purposes. Although not fully approved, anthropometric measurements have been suggested as a substitute, and considering displacement of soft tissues, could possibly lead to more consistent results. The purpose of this study was to evaluate the r...

BACKGROUND Cartilage lesions of the knee are difficult to treat. Lesion size is a critical factor in treatment algorithms, and the accurate, reproducible sizing of lesions is important. In this study, we evaluated the interrater and intrarater reliability of, and correlations in relation to, various arthroscopic sizing techniques. METHODS Five lesions were created in each of 10 cadaveric knee...

In a photographic system, the random variations in otherwise uniform responses to exposing light are referred to as grain. This two-dimensional random noise is characterized objectively by the RMS granularity. The subjective impression of this noise is termed graininess. Bartleson demonstrated that a logarithmic relationship exists between the RMS print granularity and perceived graininess as m...

Do concrete learning materials promote strong learning outcomes, or do they simply make learning tasks more initially accessible? Although concrete materials may offer an intuitive foothold on a topic, research on desirable difficulties suggests that more challenging tasks facilitate greater retention and transfer. In the approach introduced here, grounded coordination challenges (GCCs) are emb...

In a society composed of a ruler and its citizens: What are the determinants of the political equilibrium between these two? This paper approaches this problem as a game played between a ruler who has to decide the distribution of the aggregate income and a group of agents/citizens who have the opportunity to revolt if they are unhappy with the distribution. Nevertheless, if too few revolt, the...

This autobiography already makes for absolutely fascinating reading. Ibn Khaldūn lived an itinerant life serving as a magistrate for—in modern geographic terms— Spanish, Moroccan, Tunisian and Egyptian Islamic courts. In that function in Granada, Spain, he negotiated treaties with the Christian Spanish crown (with Pedro the Cruel, which does not sound too encouraging). The autobiography follows...

In 1968, Golomb and Welch conjectured that there does not exist perfect Lee code in Z with radius r ≥ 2 and dimension n ≥ 3. Besides its own interest in coding theory and discrete geometry, this conjecture is also strongly related to the degree-diameter problems of abelian Cayley graphs. Although there are many papers on this topic, the Golomb-Welch conjecture is far from being solved. In this ...

Adinkra and kente cloth have changed significantly in the course of their history first as markers of Asante royal power and then of Ghanaian cultural distinction. Once handmade and reserved for the exclusive use of the Asante ruler, cheap mass-produced reproductions now proliferate in Ghanaian markets. In attempting to use intellectual property law to regulate their appropriation, the Ghanaian...