Limits to Non-Malleability

There have been many successes in constructing explicit non-malleable codes for various classes of tampering functions in recent years, and strong existential results are also known. In this work we ask the following question: When can we rule out the existence of a non-malleable code for a tampering class ?? First, we start with some classes where positive results are well-known, and show that when these classes are extended in a natural way, non-malleable codes are no longer possible. Specifically, we show that no non-malleable codes exist for any of the following tampering classes: - Functions that change d/2 symbols, where d is the distance of the code; - Functions where each input symbol affects only a single output symbol; - Functions where each of the n output bits is a function of n-log n input bits. Furthermore, we rule out constructions of non-malleable codes for certain classes ? via reductions to the assumption that a distributional problem is hard for ?, that make black-box use of the tampering functions in the proof. In particular, this yields concrete obstacles for the construction of efficient codes for NC, even assuming average-case variants of P ? NC

A systematic review and meta-analysis of the criterion validity of nutrition assessment tools for diagnosing protein-energy malnutrition in the older community setting

Background: Accurate diagnosis is a key step in managing protein-energy malnutrition. This review seeks to determine the criterion (concurrent and predictive) validity and reliability of nutrition assessment tools in making a diagnosis of protein-energy malnutrition in community-living older adults. Methods: A systematic literature review was undertaken using six electronic databases in September 2016. Studies in any language were included which measured malnutrition via a nutrition assessment tool in adults ≥65 years living in their own homes. Data relating to the predictive validity of tools were analysed via meta-analyses. GRADE was used to evaluate the body of evidence. Results: There were 6,412 records identified, of which eight papers were included. Two studies evaluated the concurrent validity of the Mini Nutritional Assessment (MNA) and Subjective Global Assessment (SGA) and six evaluated the predictive validity of the MNA. The quality of the body of evidence for the concurrent validity of both the MNA andSGA was very low. The quality of the body of evidence for the predictive validity of the MNA in detecting risk of death was moderate (RR: 1.92 [95%CI: 1.55-2.39]; P Conclusions: Due to the small number of studies identified and no evaluation of the predictive validity of tools other than the MNA, there is insufficient evidence to recommend a particular nutrition assessment tool for diagnosing protein-energy malnutrition in older adults in the community setting. High quality diagnostic accuracy studies are needed for all nutrition assessment tools used in older community samples, including measuring of health outcomes subsequent to nutrition assessment by the SGA and PG-SGA

A systematic review and meta-analysis of the criterion validity of nutrition assessment tools for diagnosing protein-energy malnutrition in the older community setting (the MACRo Study)

Background & aims: Malnutrition is a significant barrier to healthy and independent ageing in older adults who live in their own homes, and accurate diagnosis is a key step in managing the condition. However, there has not been sufficient systematic review or pooling of existing data regarding malnutrition diagnosis in the geriatric community setting. The current paper was conducted as part of the MACRo (Malnutrition in the Ageing Community Review) Study and seeks to determine the criterion (concurrent and predictive) validity and reliability of nutrition assessment tools in making a diagnosis of protein-energy malnutrition in the general older adult community. Methods: A systematic literature review was undertaken using six electronic databases in September 2016. Studies in any language were included which measured malnutrition via a nutrition assessment tool in adults ≥65 years living in their own homes. Data relating to the predictive validity of tools were analysed via meta-analyses. GRADE was used to evaluate the body of evidence. Results: There were 6412 records identified, of which 104 potentially eligible records were screened via full text. Eight papers were included; two which evaluated the concurrent validity of the Mini Nutritional Assessment (MNA) and Subjective Global Assessment (SGA) and six which evaluated the predictive validity of the MNA. The quality of the body of evidence for the concurrent validity of both the MNA and SGA was very low. The quality of the body of evidence for the predictive validity of the MNA in detecting risk of death was moderate (RR: 1.92 [95% CI: 1.55–2.39]; P < 0.00001; n = 2013 participants; n = 4 studies; I2: 0%). The quality of the body of evidence for the predictive validity of the MNA in detecting risk of poor physical function was very low (SMD: 1.02 [95%CI: 0.24–1.80]; P = 0.01; n = 4046 participants; n = 3 studies; I2:89%). Conclusions: Due to the small number of studies identified and no evaluation of the predictive validity of tools other than the MNA, there is insufficient evidence to recommend a particular nutrition assessment tool for diagnosing PEM in older adults in the community. High quality diagnostic accuracy studies are needed for all nutrition assessment tools used in older community samples, including measuring of health outcomes subsequent to nutrition assessment by the SGA and PG-SGA

FARM COMPUTER ADOPTION IN THE GREAT PLAINS

Computers change rapidly, yet the last survey on computer use in agriculture was in 1991. We surveyed Great Plains producers in 1995 and used logit analysis to characterize adopters and non-adopters. About 37% of these producers use computers which is consistent with the general population. We confirmed previous surveys emphasizing the importance of education, age/experience, and other farm characteristics on adoption. However, we also found that education and experience may no longer be a significant influence. Future research and education could focus on when and where computers are most needed, and therefore when adoption is most appropriate.adoption, agriculture, computers, farmers, Great Plains, logit, Farm Management,

Non-Malleable Codes for Small-Depth Circuits

We construct efficient, unconditional non-malleable codes that are secure against tampering functions computed by small-depth circuits. For constant-depth circuits of polynomial size (i.e. $\mathsf{AC^0}$ tampering functions), our codes have codeword length $n = k^{1+o(1)}$ for a $k$-bit message. This is an exponential improvement of the previous best construction due to Chattopadhyay and Li (STOC 2017), which had codeword length $2^{O(\sqrt{k})}$. Our construction remains efficient for circuit depths as large as $\Theta(\log(n)/\log\log(n))$ (indeed, our codeword length remains $n\leq k^{1+\epsilon})$, and extending our result beyond this would require separating $\mathsf{P}$ from $\mathsf{NC^1}$. We obtain our codes via a new efficient non-malleable reduction from small-depth tampering to split-state tampering. A novel aspect of our work is the incorporation of techniques from unconditional derandomization into the framework of non-malleable reductions. In particular, a key ingredient in our analysis is a recent pseudorandom switching lemma of Trevisan and Xue (CCC 2013), a derandomization of the influential switching lemma from circuit complexity; the randomness-efficiency of this switching lemma translates into the rate-efficiency of our codes via our non-malleable reduction.Comment: 26 pages, 4 figure

VARIABLE GROWTH IMPACTS ON OPTIMAL MARKET TIMING IN ALL-OUT PRODUCTION SYSTEMS

This paper addresses the economic impacts of growth variability on market timing decisions in an all-in, all-out production system. Marketing decisions based on the pen average are determined to be different than those based on the entire distribution of output levels. A case study data set of 350 swine provides verification of our theoretical construct.Production Economics,

EVOLVING CONSERVATION EASEMENT MARKETS IN THE WEST

Land Economics/Use,

Patchwork Regulations: The Communicative Constitution of Compliance Across The Financial Industry

Our existing models of compliance in financial institutions cannot account for the myriad of agencies at work in compliance practice. This study challenges these oversimplified models, instead investigating the experience of compliance through the application of Communication as Constitutive of Organization (CCO) theorizing. Using both ethnographic and discourse analytic methodologies, this study addresses data collected across four financial institutions to explore the situated experience of financial compliance. This project investigates how participants account for compliance, identifies the variety of agencies at work in the communicative constitution of compliance, and lastly interrogates the situated negotiation of authority in compliance practice. This research contributes to the scholarly exploration of agency through a ventriloqual lens (Cooren, 2010) and the situated authorities of compliance. Specifically, this project offers the means for researchers and practitioners to engage with the often-overlooked complexities of compliance practice by reframing compliance as communication.</p