Miracle-dz/UniFAR-FTUs huggingface dataset:
Biases from Overlooking Price Discrimination and a Solution

Researchers often ignore price discrimination, instead assuming that all consumers face the sales-weighted average price. We show this introduces measurement error, biasing upwards the quantity demanded and the absolute slope of demand. These biases persist even with instrumental variable methods. We then propose a novel solution, and estimate the bias magnitude in the luxury car market. Despite only observing modest price discrimination price rarely deviates from the average by more than 4% we find evidence that demand is biased upwards by 5% to 14%, and its slope magnitude by 4% to 10%. This paper first proves that because price discrimination is widespread but often ignored by researchers, estimates of both the quantity demanded at a given price and the absolute slope of demand are biased upwards. Moreover, these biases persist even when standard instrumental variable methods are used. Second, this paper introduces and implements a novel demand estimation method which solves this problem. In the process, a useful tangential result is found biased demand estimates can still be used to yield unbiased estimates of firms’ marginal costs. The biases arise from aggregation. Researchers using aggregate data often assume that the price of a product equals revenues divided by quantity sold. This assumption is valid when the firm charges all consumers the same price. But when firms price discriminate, then dividing revenues by quantity sold yields the sales-weighted average price. Some consumers face prices above it, and others below it. Assuming all consumers are offered the average price introduces measurement error. Problems ensue. Consumers offered prices below the average price would likely buy less if charged the average price. However, by assuming all consumers face the average price, we are implicitly assuming these consumers would buy the same amount at the average price. Thus their demand is weakly overestimated. However, by the same logic, assuming consumers who were charged higher than average prices instead faced the average price weakly underestimates their demand. Thus, at first glance, the existence of a bias is obvious, but the direction is not. Others (Aguirre et al. [2010], Robinson [1933], Schmalensee [1981]) looking at the related question of whether discriminatory pricing yields higher or lower sales than optimally-set uniform prices find ambiguous results, seemingly confirming the ambiguity. We show otherwise when appropriately comparing sales under price discrimination to sales when uniformly charging the average price, rather than to sales at the optimally-set uniform price, this ambiguity disappears. The bias is always positive demand is overestimated. It follows that the demand function’s slope magnitude is biased upwards too. Note, measurement
Mating Behavior of Douglas-fir Tussock Moth, Orgyia pseudotsugata (Lepidoptera: Lymantriidae), with Special Reference to Effects of Female Age

Mating behavior of Douglas-fir tussock moth, Orgyia pseudotsugata (McDonnough), is described. Both males and females are capable of mating more than once, with egg fertility remaining the same regardless of number of matings by an individual female. Oviposition occurred ½ to 3 h after mating, and some females interrupted their egg-laying to mate again. Unmated females laid eggs, but these were fewer in number and deposited in aberrant patterns as compared with fertile egg deposition by mated females. Females lived up to 7 days in the field, but attracted fewer males after 3 days. Probability of females successfully mating declined after 1 day. Twenty percent of females used as trap baits failed to attract any males.
The Comparative Performance of Long Term Contracts: Empirical evidence from long-term US coal transactions

Do discriminating contract structures imply systematic differences in performance? While causal mechanisms that explain the type of contract chosen are now well detailed, however, considerably less is known about the performance implications of these choices. To answer this question, I investigate the performance effects of coal procurement behavior over two decades by electric utilities in the US. I find prices to be lower under fixed price contracts, by between 7% to 20% of the total transaction price . Renegotiations are less likely under escalator contracts, but cannot be interpreted as opportunistic under any contract structure. Supplier productivity appears to increase substantially under fixed price contracts. Contract choices appear consistent with a trade-off between establishing incentives exante and lowering negotiation costs ex-post, with relationship specific investments making such a trade-off compelling. I thank Rob Williams, Anna Alberini, Peter Murrell, Erik Lichtenberg, Howard Leathers, Sushant Acharya, Kabir Malik, Carlos Martins-Filho and seminar participants at the 2014 Western Economic Association conference in Denver for their comments. Ian Lange provided the MSHA data, for which I am grateful.
On the Nature of Cover

Cover is a magic word in wildlife management. It is, indeed, often a magic wand with which wild animals and birds are made to populate places formerly uninhabitable, or unfavorable for increase. Nevertheless, we know very little about the nature of cover and the part that it plays in the protective system of the prey. Since wildlife management seeks to develop its practice on a basis of scientific principles, rather than upon the blind practical tests which have obscured other fields
Diversity and life-forms of a woody-herbaceous community on the quartzite rocky complexes in the Brazilian Iron Quadrangle

Although campos rupestres are iconic rock outcrops with a high biogeographic value in Brazilian highlands, little is known about the drivers responsible for the plant community pattern. We studied the diversity and life forms of the woody and herbaceous components occurring along different phytophysiognomies of the quartzite rocky complexes in highlands of the Quadrangle, Minas Gerais State, Brazil. A total of 130 plots were allocated in three phytophysiognomies along the pedogeomorphological gradient: i) herbaceous campo rupestre; ii) upper and lower strata of montane forest (capão florestal) and iii) scrub. Overall, 4 446 individuals were sampled, distributed among 218 species, especially from families: Asteraceae, in general; Myrtaceae, in the woody community; and Poaceae and Cyperaceae, in the herbaceous community. Species diversity, life forms, and abundance showed differences between phytophysiognomies. The most frequent life form was phanerophyte (montane forest and scrub), followed by hemicryptophyte (herbaceous campo rupestre). Our study reveals marked differences in the floristic composition, species richness, and life form spectrum among phytophysiognomies on a local scale. Such differences probably indicate that there is a high environmental heterogeneity at a small spatial scale.
Lobes on Alnus glutinosa nodules contain a single major ribo-type of Frankia.

This work investigated the microbial content of nodules from alders to determine how many ribotypes of Frankia were present and which, if any, other bacteria existed within nodes from the nodules. The bacterial content of alder nodules was investigated by 454 sequencing of 16S rDNA genes. Over half of the sequences were from a single ribotype of Frankia, with nearly all other sequences coming from the chloroplast of the host plant, and other sequences (including other ribotypes of Frankia) being at < 1%. It is concluded that a single ribotype of Frankia is the major, although not unique, bacterium present in an individual lobe from an alder nodule.
Indiscriminate Interspecific Aggression Leading to Almost Sole Occupancy of Space by a Single Species of Bird

Noisy Miners Manorina melanocephala, Australian honeyeaters, reside and feed in dense colonies in open woodland all year. All other species entering these colonies are attacked, sometimes killed. M. melanocephala, through group aggression, successfully defends its colonies against intrusion and settlement by other species of birds. Comparison with scarcer populations in more structurally complex woodland, where the species is less able to eliminate others, suggests that the advantage gained by the interspecific aggression pertains to food resources, because the species forages more in a wider range of feeding zones in areas where possible competitors have been ousted. By eliminating virtually all competitors, M. melanocephala gains exclusive use of all food resources in its colonies. Such interspecific interaction is unique among birds and possibly among animals in general. Also, M. melanocephala breeds communally, i.e. many individuals feed the young in a single nest. Food items given to the young are usually very small and the number of feeding trips to the nest extremely high. This high rate of feeding may be necessitated by the relatively greater abundance of small insects, which in turn could be due to the complete absence of smaller avian competitors.
Plant phenology and the benefits of migration in a temperate ungulate

Seasonal changes in crude protein content of graminoids and herbs grazed by red deer were monitored from 1 May, or as soon as snow melt exposed the vegetation, until 15 October at five sites along an altitudinal gradient from coast to inland. Crude protein declined exponentially with time at all sites, but declined most rapidly from initially higher values at inland locations at high elevations. As a result crude protein was positively correlated with altitude and distance from the coast in early summer and negatively correlated in autumn. The relationships between protein content, date and altitude were used to estimate the quality of the diet of twelve radio-collared female red deer that migrated to summer ranges in the mountains
Measuring Substitution Patterns in Differentiated Products Industries – The Missing Instruments –

A very basic empirical question in industrial organization is the following: which products in a differentiated product market are close competitors with one another. This closeness of competition between two products is determined by the degree of consumer substitutability between them. Thus substitution patterns are the key to many supply side questions of interest. For example, the variation in substitution patterns among the products in a market can be used to study firm “conduct”: if there is a high degree of substitutability between the products of rival firms, then markups (and hence prices) should be systematically lower for these products when firms are competing as compared to colluding (Bresnahan 1981, Bresnahan 1987). Furthermore, for any particular hypothesis about firm conduct, substitution patterns drive the effect of counter-factual policy changes on market outcomes, such as mergers, new product introductions, etc. Although substitution patterns are central to empirical work in imperfectly competitive markets, identifying these substitution patterns from market price and quantity data has proven very challenging. The mixed-logit model of demand made famous by Berry et al. (1995) (BLP) can in principle approximate very rich substitution patterns by relaxing the strong ex-ante restrictions that the simple logit places on cross price elasticities. This is achieved by allowing for consumers to have unobserved taste heterogeneity for observed product characteristics, i.e., random coefficients in utility. While their approach has been hugely influential in providing a general framework for studying differentiated product markets, there are very few direct applications of this framework that have found statistically and/or economically significant departures from the simple logit in practice. The most prominent applications that have successfully recovered non-trivial substitution patterns use information that is "external" to the mixed logit demand structure, such as supply restrictions, micro moments, or second choice data. This basic user experience has led to two very important consequences for research with differentiated products. The first is that it has led to a growing questioning of whether the underlying taste heterogeneity parameters that govern substitution patterns are even identified with market level data on prices and quantities (see e.g., Knittel and Metaxoglou (2008)). This skepticism has motivated some to abandon structural demand models in favor of natural experiments to study policy questions and more generally a movement away from mixed logit (see e.g., Ashenfelter,
Nutrient Digestibility for High-Producing Dairy Cows: How Much Milk Can You Get from a Ration?

Dietary energy comes from four main feed compound classes: fiber, starch, protein, and fat. Although fiber and starch are both carbohydrates, we will separate them in this paper is if they are different “nutrients”, and we will define fiber as neutral-detergent fiber (NDF). There are other feed compounds (such as sugars, soluble fiber, and organic acids) that do not fit into one of these four categories, but we will ignore them in this discussion. The typical Gross Energy (GE), Digestible Energy (DE), Metabolizable Energy (ME), and Net Energy for Lactation (NEL) values for these nutrients are shown in Table 1. Because the content of protein and fat is relatively constant, the major determinant of the energy available from a diet is the amount of starch and fiber and the digestibility of each. Starch is generally about 90% digested, whereas the digestibility of fiber (as NDF) can vary widely among feeds but is usually 40 to 50%. Fiber could be subdivided into that from forage and that from nonforage sources. The fiber from some nonforage sources can be quite digestible.
Why Reciprocal Teaching

Carolyn J. Carter Teachers in Highland Park, Michigan, conducted research and began an effective reading instruction program for students who were not succeeding in school. Reciprocal Teaching raised hopes, expectations, and student achievement in less than one year. • Poverty • Rigid school structure • Lack of training • Few resources and supportive systems • Deeply entrenched resistance to change • Low teacher morale • Low student achievement • Abysmal test scores • Low graduation rate
SIZE VARIABILITY OF THE TEETH IN LIVING MAMMALS AND THE DIAGNOSIS OF CLOSELY RELATED SYMPATRIC FOSSIL SPECIES

The dentitions of sympatric fossil (or living) mammalian species which share a relatively recent common ancestor often cannot be distinguished by form alone. In such cases, size differences are important in diagnosing the species. Measurements of the length and width of the lower molars and premolars of large samples of 19 species of living mammals demonstrate that M1 is usually the least variable in size, and that P3, P4, and M3 are the most variable. The low variability of M1 is presumably related to the fact that it is the first permanent tooth to form and erupt, and to its central position in the tooth row. Because of its low variability, M1 is the best tooth on which to base size diagnoses of very closely related sympatric fossil species. Examples are given of the diagnosis of two species of the fossil primates Plesiadapis (at Cernay), Pelycodus (at Avenay), and Protoadapis (at Grauves). The ability to distinguish closely related sympatric species is fundamental to reconstructing the phylogenetic history of any group from the fossil record.
The Utility of the UTAUT: An Application to Mobile Learning Adoption in the Caribbean.

This paper focuses on the usefulness of the UTAUT model in explaining behavioural intention to adopt mobile learning in the Caribbean. It employs confirmatory factor analysis with robust maximum likelihood estimation, to evaluate the measures, comparability of the measures and to compare the means of the factors between five university-territory combinations. It estimates a full structural equations model to evaluate the UTAUT relationships with an added effect of facilitating conditions on behavioural intention and it finds little support for effects of effort expectancy and social factors on behavioural intention in the region. However, the impacts of performance expectancy and effort expectancy on behavioural intention are similar across the region. With the UTAUT model underperforming in the region, there is a need for further research to strengthen measurement of the factors and to improve the explained variance by determining measures that are relevant to the regions and which can be included in a modified model.
Inhibitory Effects of Habbat Al-Sauda Seed’s (Nigella Sativa) Extract Against Some Pathogenic Bacteria Isolated from Sulaimani Teaching Hospital

To investigate the antibacterial effects of Nigella sativa seed extracts, three different concentrations of this extract (100 mg/ml , 0.1mg/ml , and 0.0 mg/ml – control-) were prepared in, and tested against (12) S. aureus isolates, (6) S. epidermidis, (15) P. aeruginosa and (14) E. coli isolates, which were isolated from Suleiman Teaching Hospital. For each bacterium three nutrient broth culture tubes were prepared and (0.25ml) of the pre-mentioned concentrations (tested) and distilled water (control) were added to the three cultivated tubes respectively. The inhibitory effects of seed extracts for the first and second cultivated tubes were determined turbidometrically at (640 nm). The effects were proportional with the extract concentration, the higher the concentration, the higher the inhibitory effects were. T-test was depended for statistically analyzing the obtained results from this study, significant differences were observed in regard to S. aureus (p= 0.00000474), S. epidermidis (p= 0.0327), P. aeruginosa (p= 0.00963) and E. coli (p= 0.03897) when the data from (100mg/ml) were compared with that of controls. Although the effects become limited (non-significant) when (0.1mg/ml) was used, but still within significant differences in regard to S. aureus (p= 0.000343) and E. coli (p= 0.0228).
Revisiting the Relationship Between Fault Detection, Test Adequacy Criteria, and Test Set Size

The research community has long recognized a complex interrelationship between fault detection, test adequacy criteria, and test set size. However, there is substantial confusion about whether and how to experimentally control for test set size when assessing how well an adequacy criterion is correlated with fault detection and when comparing test adequacy criteria. Resolving the confusion, this paper makes the following contributions: (1) A review of contradictory analyses of the relationships between fault detection, test adequacy criteria, and test set size. Specifically, this paper addresses the supposed contradiction of prior work and explains why test set size is neither a confounding variable, as previously suggested, nor an independent variable that should be experimentally manipulated. (2) An explication and discussion of the experimental designs of prior work, together with a discussion of conceptual and statistical problems, as well as specific guidelines for future work. (3) A methodology for comparing test adequacy criteria on an equal basis, which accounts for test set size without directly manipulating it through unrealistic stratification. (4) An empirical evaluation that compares the effectiveness of coverage-based testing, mutation-based testing, and random testing. Additionally, this paper proposes probabilistic coupling, a methodology for assessing the representativeness of a set of test goals for a given fault and for approximating the fault-detection probability of adequate test sets.
The Linkage of Migratory Culture and Entrepreneurship Through Information Acquisition

This research intends to analyze the linkage of migratory culture and entrepreneurship through information acquisition. The research population is migrant Madura entrepreneurs in East Java, Indonesia, with a sampling technique using a proportional random sampling at three locations: Surabaya City, Malang City and Jember Regency. The number of respondent are 170 Madura migrant entrepreneurs. The consideration is that there are relatively many Madura migrants in those cities. This research was carried out by designing questionnaires first and then validity and reability test of the research instrument. Further, the questionnaire was broadcasted to Madura migrant entreprenuers who were randomly selected. The primary data was analyzed by structural equation model with the Partial Least Square (PLS) data processing program. The research result demonstrate that migratory culture significantly affects entrepreneurship and information acquisition mediates the effect of migratory culture toward entrepreneurship. It means that information acquisition plays an important role to encourage entrepreneurship of madura migrants.
Does a lower jaw protruding device improve running aerobic performance?

Using occlusal splints aiming to increase sports performance has recently raised significant interest, being speculated that it could lead to anatomical and physiological changes like upper airway enhancement and corresponding higher oxygen uptake ( O2). We have studied the lower jaw protruding device effect in running aerobic performance. Nine active male subjects performed two testing sessions (with a placebo and with a jaw protruding device) on a treadmill, running 7 x 4 min until exhaustion with 1 km/h increments (48 h rest). O2 and related variables, blood lactate concentrations and rating of perceived exertion were determined for both experimental conditions across three intensity domains. A t-test for repeated measures was used (p < .05) For both experimental conditions and through the low-moderate, heavy and severe running intensity domains, no significant differences were observed in any of the analysed variables (e.g. O2 = 34.54 ± 3.42 vs 34.20 ± 4.89, 39.80 ± 2.39 vs 40.19 ± 4.48 and 43.58 ± 3.80 vs 44.36 ± 4.00 mL·kg−1·min-1, respectively). Data allowed to conclude that this specific lower jaw protruding device did not influence the analysed variables related with running aerobic performance at a large spectrum of exercise intensities. AUTHORS: Filipa Cardoso 1,2 Francisco Maligno 3 Diogo D. Carvalho 1,2 João Paulo Vilas-Boas 1,2 Ricardo J. Fernandes 1,2 João C. Pinho 3 1 Centre of Research, Education, Innovation and Intervention in Sport, CIFI2D, Faculty of Sport, University of Porto, Portugal 2 Porto Biomechanics Laboratory, LABIOMEP, University of Porto, Portugal 3 Faculty of Dental Medicine, University of Porto, Portugal https://doi.org/10.5628/RPCD.19. 01.72 Corresponding author: Filipa Cardoso. University of Porto. Faculty of Sport. Centre of Research, Education, Innovation and Intervention in Sport, CIFI2D. Porto Biomechanics Laboratory, LABIOMEP. R. Dr. Plácido da Costa 91, 4200-450 Porto, Portugal. +351 22 04 25 200. Email: anafg.cardoso@hotmail.com. 06 73 — RPCD 19 (1): 72-84 Um dispositivo de avanço mandibular implicará um melhor desempenho aeróbio na corrida?
Cross-National CCTV Footage Shows Low Victimization Risk for Bystander Interveners in Public Conflicts

Objective: Accumulating evidence shows that bystanders witnessing public disputes frequently intervene to help. However, little is known regarding the risks entailed for those bystanders who enter the fray to stop conflicts. This study systematically examined the prevalence of bystander victimizations and associated risk factors. Method: Data were a cross-national sample of 93 CCTV video recordings of real-life public disputes, capturing the potential victimizations of 417 intervening and 636 non-intervening bystanders. Results: Data showed that interveners were rarely physically harmed—at a rate of 3.6%—and non-interveners were virtually never victimized. Confirmatory regression results showed that conflict party affiliation was associated with bystander victimization, although only moderately robust. The gender of the intervener was a highly fragile correlate with the outcome. The severity of the conflict at the time of intervention was not found to increase the risk of victimization. Conclusions: Our findings