Parity of transversals of Latin squares

We introduce a notion of parity for transversals, and use it to show that in Latin squares of order $2 \bmod 4$, the number of transversals is a multiple of 4. We also demonstrate a number of relationships (mostly congruences modulo 4) involving $E_1,\dots, E_n$, where $E_i$ is the number of diagonals of a given Latin square that contain exactly $i$ different symbols. Let $A(i\mid j)$ denote the matrix obtained by deleting row $i$ and column $j$ from a parent matrix $A$. Define $t_{ij}$ to be the number of transversals in $L(i\mid j)$, for some fixed Latin square $L$. We show that $t_{ab}\equiv t_{cd}\bmod2$ for all $a,b,c,d$ and $L$. Also, if $L$ has odd order then the number of transversals of $L$ equals $t_{ab}$ mod 2. We conjecture that $t_{ac} + t_{bc} + t_{ad} + t_{bd} \equiv 0 \bmod 4$ for all $a,b,c,d$. In the course of our investigations we prove several results that could be of interest in other contexts. For example, we show that the number of perfect matchings in a $k$-regular bipartite graph on $2n$ vertices is divisible by $4$ when $n$ is odd and $k\equiv0\bmod 4$. We also show that $${\rm per}\, A(a \mid c)+{\rm per}\, A(b \mid c)+{\rm per}\, A(a \mid d)+{\rm per}\, A(b \mid d) \equiv 0 \bmod 4$$ for all $a,b,c,d$, when $A$ is an integer matrix of odd order with all row and columns sums equal to $k\equiv2\bmod4$

Hemobilia due to cystic artery pseudoaneurysm: A rare late complication of laparoscopic cholecystectomy

We discuss a patient with late presentation of hemobilia following cholecystectomy, which is unusual because pseudoaneurysm caused by vascular injury during surgery typically presents soon after surgery. Endoscopic retrograde cholangiopancreatography revealed a large blood clot arising from the biliary orifice with subsequent computed tomography angiography diagnosing a large pseudoaneurysm in the region of the cystic artery adjacent to the cholecystectomy clips. Embolization was performed via direct percutaneous puncture of the pseudoaneurysm

Visible Tattoos and Professional Nursing Characteristics: A Study on How Appearance Affects the Perception of Essential Qualities of Nurses

Previous studies have indicated that nurses with tattoos are viewed less favorably than nurses without tattoos, regardless of gender. Additionally, older adults are more likely to negatively evaluate nurses with tattoos than young adults. Images of male and female nurses with and without tattoos were shown to 128 participants between the ages of 18-80 years on an iPad. Participants selected according to gender which nurse possessed more of the following professional characteristics based on their initial impression of their physical traits, or selected no difference: respectfulness, kindness, trustworthiness, intelligence and competence. The study showed that male nurses with tattoos were perceived the same as male nurses without tattoos across all ages of participants, but female nurses with tattoos were perceived to be less kind and less trustworthy than female nurses without tattoos across all ages of participants. Participants’ genders did not affect their responses. The results were discussed with respect to the overall decreasing stigma of visible tattoos on nurses as well as the implications of the results for male and female nurses with tattoos

Roadway System Assessment Using Bluetooth-Based Automatic Vehicle Identification Travel Time Data

This monograph is an exposition of several practice-ready methodologies for automatic vehicle identification (AVI) data collection systems. This includes considerations in the physical setup of the collection system as well as the interpretation of the data. An extended discussion is provided, with examples, demonstrating data techniques for converting the raw data into more concise metrics and views. Examples of statistical before-after tests are also provided. A series of case studies were presented that focus on various real-world applications, including the impact of winter weather on freeway operations, the economic benefit of traffic signal retiming, and the estimation of origin-destination matrices from travel time data. The technology used in this report is Bluetooth MAC address matching, but the concepts are extendible to other AVI data sources

LOCATION OF VERTICALLY LINKED INDUSTRIES UNDER FREE TRADE: CASE STUDIES OF ORANGE JUICE AND TOMATO PASTE IN THE WESTERN HEMISPHERE

The objective of this study was to determine the economic impact on the United States of removing tariff barriers on imports of concentrated orange juice and tomato paste from South America. The study highlighted an agglomeration model of industry location recognizing imperfect competition and increasing returns. The results were contrasted with those from a competitive model with conventional estimates of supply and demand elasticities. Because the assumptions of the models differed, the results also differed. The agglomeration model indicated that the United States would gain market share of production and processing with the removal of tariffs. In contrast, the competitive model indicated that the United States would lose market share in production and processing. According to the competitive model, US consumers would gain, producers would lose, and the government would lose from less tariff revenue, but the gains to consumers would offset losses elsewhere so that national income would rise. In South America, consumers would lose, producers would gain, and national incomes would rise. In the long run, countries would individually and collectively gain from freer trade in fruits and vegetables. Both models indicated that American production and processing of oranges and tomatoes would not be displaced by removing barriers to international trade.oranges, tomatoes, juice, paste, model, agglomeration, competitive, comparative advantage., Industrial Organization, International Relations/Trade,

A CROSS-SECTION ANALYSIS OF INTRA-INDUSTRY TRADE IN THE U.S. PROCESSED FOOD AND BEVERAGE SECTORS

This paper analyzes the determinants of variation across industries in levels of intra-industry trade (IIT) for a sample of 36 U.S. processed food and beverage industries in 1987, previous studies of intra-industry trade having focused on industry characteristics in the manufacturing sectors. The determinants predicted by IIT theory are measures of product differentiation, economies of scale, and imperfect competition; the results of this analysis indicate that IIT variation across the food and beverage industries is positively related to product differentiation, U.S. total trade, similarity of tariff barriers among trade partners, and economies of scope, but negatively related to industry concentration.International Relations/Trade,

Animal Handling Safety

Animals are handled daily on nearly half of New York farms. In the Northeast, animal handling accidents rank second in reported farm accidents. Every year at least one New York farmer dies as a direct result of a confrontation with a farm animal. This factsheet covers animal characteristics, hazards and precautions, and safe facilities