Testable Hypotheses Implied by a Linear Hypothesis

ROY and ROY have shown that for any linear hypothesis H being not testable it is possible to construct a testable hypothesis which is implied by H. A maximal testable hypothesis implied by H is presented.     

The honey bee "language" controversy

The controversy between the honey bee “language” hypothesis and the olfactory hypothesis, is essentially a controversy between a human-level hypothesis and an insect-level hypothesis, for an insect. A careful analysis of the theoretical process which underlies the design of experiments and interpretation of results, demonstrates that the proof that honey bees can use a “language” of abstract symbols, remains as inconclusive and non-valid as ever.     

Reassessing the amyloid cascade hypothesis of Alzheimer's disease

Since its inception, the amyloid cascade hypothesis has dominated the field of Alzheimer's disease (AD) research and has provided the intellectual framework for therapeutic intervention. Although the details of the hypothesis continue to evolve, its core principle has remained essentially unaltered. It posits that the amyloid-β peptides, derived from amyloid precursor protein (APP), are the root cause of AD. Substantial genetic and biochemical data support this view, and yet a number of findings also run contrary to its tenets. The presence of familial AD mutations in APP and presenilins, demonstration of Aβ toxicity, and studies in mouse models of AD all support the hypothesis, whereas the presence of Aβ plaques in normal individuals, the uncertain nature of the pathogenic Aβ species, and repeated disappointments with Aβ-centered therapeutic trials are inconsistent with the hypothesis. The current state of knowledge does not prove nor disprove the amyloid hypothesis, but rather points to the need for its reassessment. A view that Aβ is one of the factors, as opposed to the factor, that causes AD is more consistent with the present knowledge, and is more likely to promote comprehensive and effective therapeutic strategies.     

Action of dimeric hybrids of native and selectively alkylated ribonuclease A on double-stranded ribonucleic acid (Short Communication)

The hypothesis that both active sites of dimeric ribonuclease A have to be simultaneously available in order to make the enzyme able to degrade double-stranded RNA is tested with purified hybrid dimers of ribonuclease A and its carboxymethylated derivative. The results obtained support the hypothesis.     

Disinfection kinetics: a new hypothesis and model for the tailing of log-survivor/time curves

A new hypothesis for the understanding of chemical disinfection, which we have termed the Intrinsic Quenching hypothesis, is presented. This mechanistic treatment of disinfection kinetics is based on the hypothesis that the biocide concentration may not be in vast excess over the microbes, as is normally assumed. A mathematical model was developed and found to be useful in describing the observed kinetics of several disinfectants. The model suggested that the reason for the observation of non-linear, log-survivor curves was due to the ability of the microbes, in clean, soil-free conditions, to intrinsically quench the bulk concentration of biocide.     

神经元簇的层次性联合编码假设

提出一个新的神经信息编码假设,称为神经元簇的层次性联合编码假设。它不同于祖母细胞假设和Hebb经典细胞群编码模型,但融合了它们的优点,因而可以解释更多的神经生物学实验。     

Was August Weismann right?

A new hypothesis of the genetic regulation of cell differentiation is put forward. The hypothesis is based on the assumption that the diminution and hyper-replication patterns of repetitive nucleotide sequences depend on the differentiation pathways of cells and tissues.     

基于淀粉样蛋白级联假说的阿尔茨海默症防治研究进展

阿尔茨海默症（Alzheimer＇s Disease,AD）是一种中枢神经系统退行性病变,目前发病机制不清。淀粉样蛋白级联假说是有关AD发病机制的主流学说,认为脑内过量产生的β-淀粉样蛋白（β-amyloid peptide,Aβ）是引发AD的主要原因。针对Aβ的生成、聚集、清除及靶向治疗相关的药物开发是目前的研究热点,就淀粉样蛋白级联假说的最新研究进展及AD的预防治疗现状作一综述。     

Was August Weismann Right?

A new hypothesis of the genetic regulation of cell differentiation is put forward. The hypothesis is based on the assumption that the diminution and hyperreplication patterns of repetitive nucleotide sequences depend on the differentiation pathways of cells and tissues.     

An appraisal of how the vitamin A‐redox hypothesis can maintain honesty of carotenoid‐dependent signals

The vitamin A‐redox hypothesis provides an explanation for honest signaling of phenotypic quality by carotenoid‐dependent traits. A key aspect of the vitamin A‐redox hypothesis, applicable to both yellow and red coloration, is the hypothesized negative feedback of tightly regulated Vitamin A plasma levels on the enzyme responsible for sequestering both Vitamin A and carotenoids from the gut. We performed a meta‐analysis and find that vitamin A levels are positively related to carotenoid plasma levels (r = 0.50, P = 0.0002). On the basis of this finding and further theoretical considerations, we propose that the vitamin A‐redox hypothesis is unlikely to explain carotenoid‐dependent honest signaling.     

A critical review of the McCredie-McBride hypothesis of neural crest influence on limb morphogenesis

A number of hypotheses have been presented to explain the mechanism of action of thalidomide. The most widely published and apparently widely accepted hypothesis is that of embryonic neuropathy advanced by McCredie and McBride. This paper reviews the points of the hypothesis and analyzes it in light of known limb embryology supported with recent experimental evidence which directly tests the hypothesis. The hypothesis may be considered as being composed of two separate parts. The first part proposes that thalidomide-induced limb defects exhibit a segmental pattern. The second proposes that the segmental pattern of limb defects is a result of segmental peripheral neuropathy. We are in complete agreement with the first portion of the hypothesis, but find the second portion quite unlikely.     

The Alzheimer's disease mitochondrial cascade hypothesis: Progress and perspectives

Ten years ago we first proposed the Alzheimer's disease (AD) mitochondrial cascade hypothesis. This hypothesis maintains that gene inheritance defines an individual's baseline mitochondrial function; inherited and environmental factors determine rates at which mitochondrial function changes over time; and baseline mitochondrial function and mitochondrial change rates influence AD chronology. Our hypothesis unequivocally states in sporadic, late-onset AD, mitochondrial function affects amyloid precursor protein (APP) expression, APP processing, or beta amyloid (Aβ) accumulation and argues if an amyloid cascade truly exists, mitochondrial function triggers it. We now review the state of the mitochondrial cascade hypothesis, and discuss it in the context of recent AD biomarker studies, diagnostic criteria, and clinical trials. Our hypothesis predicts that biomarker changes reflect brain aging, new AD definitions clinically stage brain aging, and removing brain Aβ at any point will marginally impact cognitive trajectories. Our hypothesis, therefore, offers unique perspective into what sporadic, late-onset AD is and how to best treat it. This article is part of a Special Issue entitled: Misfolded Proteins, Mitochondrial Dysfunction, and Neurodegenerative Diseases.     

On compromise in foraging and an experiment by Krebs et al. (1977)

A vectorized version of the method of stochastic dynamic programming is used to demonstrate that behaviour observed in Parus major by Krebs et al. (1977) is more consistent with the hypothesis that animals compromise between time and energy in foraging than with the hypothesis that they maximize their rate of energy gain.     

A new hypothesis for the evolution of overproduction of ovules: an advantage of selective abortion for females not associated with variation in genetic quality of the resulting seeds

A new hypothesis for the evolution of overproduction of ovules within flowers is proposed: overproduction is a counter-strategy of female seed production in the conflict with males and/or offspring. It is advantageous for females to produce a uniform size of seeds, whereas it is advantageous for fertilized ovules to absorb more resources than this size. If there is a variance in resource absorption ability among fertilized ovules, nonuniform seeds are produced. Then, by overproducing ovules, females should select fertilized ovules with similar resource absorption rates, resulting in seeds of uniform size. A model analysis confirmed that this hypothesis works. In the model, the fertilized ovules of a plant consist of two genotypes that differ in resource absorption rate. I found that overproduction of ovules and selective abortion is advantageous if the difference in the resource absorption rates of the genotypes is large. The new hypothesis is different from the selective abortion hypothesis in that selecting ovules is advantageous even if there are no differences in the genetic quality of resulting seeds.     

综述:靶向淀粉样蛋白的阿尔茨海默病药物研究进展

淀粉样蛋白级联假说是阐释阿尔茨海默病(Alzheimer's disease,AD)发病机制的主要学说之一,即脑内过量的β-淀粉样蛋白(β-amyloid,Aβ)是促发AD的核心因素．因此,靶向Aβ形成、聚集和清除等关键环节的药物开发是目前药物研究的热点．但近年来AD新药临床试验屡屡失败,至今尚未得到一种切实有效的治疗药物．淀粉样蛋白级联假说的局限性和痴呆期患者疾病进程的难以逆转,可能是临床试验反复失败的两个主要原因．借助AD早期诊断技术的发展,将药物干预的时间窗口前移,重视痴呆前期病理机制与治疗的研究,可能是研制延缓AD发生和发展有效药物的新途径．     

What Is the Sapir-Whorf Hypothesis?

The history of empirical research on the Sapir-Whorf hypothesis is reviewed. A more sensitive test of the hypothesis is devised and a clear Whorfian effect is detected in the domain of color. A specific mechanism is proposed to account for this effect and a second experiment, designed to block the hypothesized mechanism, is performed. The effect disappears as predicted. The Sapir-Whorf hypothesis is reevaluated in the light of these results.     

The genetic hypothesis for susceptibility to lepromatous leprosy

Summary Evidence for genetic influence of the host response to infection with Mycobacterium leprae is reviewed. A complex segregation analysis is performed on data for 91 families from Mactan, Philippines, in each of which at least one offspring developed lepromatous leprosy. The data are not found to be inconsistent with an autosomal recessive hypothesis for susceptibility to lepromatous leprosy. Heritability estimates in the range of 80% were calculated for sib-sib pairs under the multifactorial hypothesis for susceptibility. It is argued that the multifactorial hypothesis is more in keeping with available immunologic, epidemiologic, and demographic data than is the single gene hypothesis.     

Normal greeble learning in a severe case of developmental prosopagnosia

A central question in cognitive neuroscience is whether mechanisms exist that are specialized for particular domains. One of the most commonly cited examples of a domain-specific competence is the human ability to recognize upright faces. However, according to a widely discussed alternative hypothesis, face recognition is instead performed by mechanisms specialized for processing any object class for which an individual has expertise. Faces, according to this domain-general hypothesis, are just one example of an expert class. Nonface object expertise has been intensively investigated using a training procedure involving an artificial stimulus class known as greebles. A key prediction of this hypothesis is that individuals with face recognition impairments will also have impairments with other categories that control subjects have expertise with. Our results show that a man with severe prosopagnosia performed normally throughout the standard greeble training procedure. These findings indicate that face recognition and greeble recognition rely on separate mechanisms.     

An investigation of the basis of a current hypothesis for the lack of G-banding in plant chromosomes

A current hypothesis for the lack of G-banding in plant chromosomes is based on the assumption that plant chromosomes are more compact than animal chromosomes. We tested the basis of the hypothesis by measuring lengths and volumes of plant and animal chromosomes that had been similarly treated. We conclude there is no consistent difference in the compaction of plant vs animal chromosomes.     

Appendix to Paper by Wall and Herbeck

A method is described for determining the number of preferred codons in taxa in which G+C levels differ. If the hypothesis of random codon usage is not rejected, there are no preferred codons. If that hypothesis is rejected, then a model with one or two preferred codons is fitted to the data and a likelihood ratio test is used to determine whether there are one or two preferred codons. A C++ program is freely available to perform the calculations.