The purpose of this paper is to disclose the design techniques and experimental methodologies for the stabilization of X-band phase locked loop (PLL) phase noise performance during random vibration environment. Phase noise performance of PLL based unit under test (UUT) is very prone to disturbance occurred in random vibration profile frequency spectrum. UUT self-resonance plays vital role in occurrence of disturbance in random vibration profile. The stabilization of phase noise performance during dynamic (random vibration) condition is achieved by following methodologies, i.e. vibration-isolator compensation technique, purification tactic of crystal reference of PLL and spatial location analysis for mounting of crystal reference. Spatial analysis helps to filter out UUT self-resonance from frequency spectrum of random vibration profile which ultimately leads to reduction of frequency resonance pickups during random vibration testing.

Many organisms time reproduction to photoperiod, a constant from year to year.  Predicting how anthropogenic change will influence future timing demands greater knowledge of the current role of photoperiod.  We held two closely related bird populations in a common environment. One population is resident; the other winters in sympatry with the resident population but migrates north prior to reproducing. We increased photoperiod gradually and measured preparation for migration and reproduction, using feather stable isotopes to estimate breeding latitude. We predicted population differences in the minimum stimulatory day length to elicit a response (CPP, critical photoperiod) and co-variation between CPP and distance migrated. We found clear population differences in CPP and greater CPP in longer distance migrants. We conclude that current geographic variation in reproductive timing has a genetic or early developmental basis and recommends that future research focus on how anthropogenic changes will interact with CPP to adjust the timing of reproduction and migration.

Web applications have become a backbone for organizations especially in managing information, because running any organization through the classic way makes the process hard. This paper tries to develop a web-based system that helps the supervisors of an electric power generator in handling the problems they face in managing customer information. Through the manual process, the supervisors spend a lot of time and money and despite inefficiency and inaccuracy of paper-work, it is tiresome. The system will be developed with ASP.NET web framework and MySQL open source database management system. Ajax and jQuery library will be utilized for smart searching facility and printing dynamic receipts. It will be easy to use and supports all smart devices because of the help of bootstrap framework. IIS web server and Microsoft Azure cloud virtual machine are used for hosting and running the system. As a result of this system, the supervisors of electric power generator can manage customers' information in a reliable, fast and efficient way and it will save a lot of time and money and they would be able to back-up data easily.

We present a numerical method for simulating 2D flow through a channel with deformable walls. The fluid is assumed to be incompressible and viscous. We consider the highly viscous regime, where fluid dynamics are described by the Stokes equations, and the less viscous regime described by the Navier-Stokes equations. The model is formulated as an immersed boundary problem, with the channel defined by compliant walls that are immersed in a larger computational fluid domain. The channel traverses through the computational domain, and the walls do not form a closed region. When the walls deviate from their equilibrium position, they exert singular forces on the underlying fluid. We compute the numerical solution to the model equations using the immersed interface method, which preserves sharp jumps in the solution and its derivatives. The immersed interface method typically requires a closed immersed interface, a condition that is not met by the present configuration. Thus, a contribution of the present work is the extension of the immersed interface method to immersed boundary problems with open interfaces. Numerical results indicate that this new method converges with second-order accuracy in both space and time, and can sharply capture discontinuities in the fluid solution.

This is a fundamental study addressing the articulation of knowledge from the context of the fourth industrial revolution (Industry 4.0). Industry 4.0 employs embedded systems (e.g., cyber-physical systems) to perform cognitive tasks. These systems cannot work without applying digitized knowledge. As a result, the digitization of knowledge-intensive activities (knowledge acquisition, representation, dissemination, utilization, and management) is critical for Industry 4.0. Before digitizing the knowledge and knowledge-intensive activities, a fundamental question arises: What is knowledge in Industry 4.0? This study answers this question. In doing so, this study first reviews the definitions of knowledge reported in the extant literature of epistemology, engineering design, manufacturing, organization science, information science, and education science. This study then defines that a piece of knowledge consists of three elements, namely, claim, provenance, and inference. Such a definition helps overcome the circularity and ambiguity in the definitions of knowledge reported so far. This definition results in four types of knowledge, namely, definitional, deductive, inductive, and creative knowledge. These types of knowledge are exemplified using some real-life scenarios relevant to engineering design and manufacturing. The exemplified pieces of knowledge are also represented by using knowledge graphs (concept maps) so that the contents can easily be digitized for human and machine learning. The outcomes of this study are the fundamentals based on which more sophisticated methods and tools can be developed to perform the cognitive tasks relevant to Industry 4.0.

The young water fraction (Fyw), the proportion of water younger than 2-3 months, was investigated in soil-, ground- and stream waters in the 0.56 Km2 sub-humid Mediterranean Can Vila catchment. Rain water was sampled at 5-mm rainfall intervals. Mobile soil water and groundwater were sampled fortnightly, using suction lysimeters and two shallow wells, respectively. Stream water was dynamically sampled at variable time intervals (30 minutes to 1 week), depending on flow. A total of 1,529 18O determinations obtained during 58 months were used. The usual hypothesis of rapid evapotranspiration of summer rainfall could not be maintained, leading to discard the use of an “effective precipitation” model. Soil mobile waters had Fyw up to 34%, while in ground and stream were strongly related to water table and discharge variations, respectively. In stream waters, due to the highly skewed flow duration curve, the flow-averaged young water fraction (F*yw) was 22.6%, whereas the time-averaged Fyw was 6.2%. Nevertheless, both F*yw and its exponential discharge sensitivity (Sd) showed relevant changes when different 12-month sampling periods were investigated. The availability of Sd and a detailed flow record allowed us to simulate the young water fraction that would be obtained with a virtual thorough sampling (F**yw). This showed that underestimation of F*yw is associated with missing the sampling of highest discharges and revealed underestimations of F*yw by 25% for the dynamic sampling and 66% for the weekly sampling. These results confirm that the young water fraction and its discharge sensitivity are metrics that depend more on precipitation forcing than on physiographic characteristics, so the comparisons between catchments should be based on mean annual values and inter-annual variability. They also support the dependence of the young water fraction on the sampling rate and show the advantages of flow-weighted F*yw. Water age investigations should be accompanied by the analysis of flow duration curves. In addition, the simulation of F**yw is proposed as a method for checking the adequacy of the sampling rate used.

Abstract Diverse hypotheses exist to explain allergic and autoimmune diseases. There are 3 factors common to most, if not all, of these diseases: 1. Microbial imbalances, microbial triggers and/or infections, 2. Allergy/hypersensitivity to food and/or environmental substances and 3. Stress. The post-hunter-gatherer era microbe hypersensitivity-enhanced colonization/infection (PHMHEC) hypothesis presented here proposes that these factors are part of a phenomenon that involves an extension of the altered microbiota hypothesis, which is the current leading hypothesis to explain the increase in allergic and autoimmune diseases in the last 75 years in association with westernization. The category of post-hunter-gatherer era microbes (PHM), as defined here, includes many microbes that are encountered much more frequently since humans ceased to live as nomadic hunter-gatherers and began living an agricultural or urban lifestyle. The microbial communities (microbiotas) that humans have been exposed to have changed as human activities have changed. It is postulated that the most intense and rapid changes in these microbiotas have occurred in recent decades in association with westernization. Human genetic makeup evolved largely during the 200 million years during which humans and their mammalian ancestors lived as hunter-gatherers or gatherers. It is proposed here that environmental microbes commonly encountered in association with that lifestyle in a pre-agricultural age would be the most coevolved with the human immune system, and thus the immune system would generally respond to these microbes without leading to debilitating chronic disease. In contrast, according to the PHMHEC hypothesis, at least some of the microbes newly encountered or encountered at higher levels during the post-hunter-gatherer era, the PHM, would be more likely to evade the immune system and cause hypersensitivity reactions. A mechanism called hypersensitivity-enhanced colonization/infection (HEC) is postulated to be one means by which low abundance microbes cause disease. Microbes sometimes cause hypersensitivity reactions in a manner that increases their virulence, and these reactions could be enhanced by increased exposure to similar or identical microbes in the environment. Slight differences between antigens of environmental and colonizing microbes could make the colonizing microbes even more difficult for the immune system to effectively target. Multiple secondary opportunistic infections resulting from PHM-induced immunosuppression and/or immune dysregulation could exacerbate disease processes. The long-term colonization/infection of multiple PHM and accompanying hypersensitivity reactions could contribute to physiological and psychological stress and tax the immune system and other systems of the body and be an underlying factor leading to many allergic, autoimmune and related diseases. The united holobiont disease hypothesis, which is analogous to the united airway disease hypothesis, is discussed, as well as the view that the concept of sterile inflammation needs revision and perhaps should be replaced with “inflammation without apparent infection” (IWAI) in light of the potential role of low abundance microbes. The relationship between the PHMHEC hypothesis and other hypotheses is discussed for a variety of diseases, ending with a discussion of implications for research and treatment.Keywords: Autoimmune, Allergy, Hypersensitivity, Microbiota, Hygiene Hypothesis, Cross-Reaction, Occupational Health, Plant-based Diet

In this article, a highly robust antenna is proposed for omnidirectional circular polarized communications in harsh environments at 2.45 GHz industrial, scientific, and medical frequency band. Circular polarization is realized by utilizing a combination of two magnetic and electric dipoles. The proposed antenna is based on a transparent structure and covered by a quarter wavelength thick layer of plexiglass to achieve desired robustness and visible light transparency.Meanwhile, because of the high transparency of the glass, it can integrate with solar cells to simultaneously propagate signals and harvest energy. The average gain and bandwidth of the antenna are 1.7 dBic and 300 MHz, respectively. The antenna’s axial ratio is achieved less than 3 dB within the bandwidth, showing circular polarization behavior. The proposed compact antenna is numerically and experimentally analyzed and the results have a great agreement. In another viewpoint, the structure delivers promising possibilities to improve the propagating and radiating properties, which bring in significant advantages for real-world multifunctional applications.

It is assumed that linear time-invariant (LTI) system input signal samples are updated by a sensor in real time. It is urgent for every new input sample or for small part of new samples to update an ordinary convolution as well. The idea is that well-known convolution sum algorithm, used to calculate output signal, should not be recalculated from the begining with every new input sample. It is necessary just to modify the algorithm, when the new input sample renew the set of previous samples. The recursive algorithm is worked out for such a purpose. Example of recursive computation of the convolution is presented. Conclusion is given.

A document by Mattia Andreoletti, written on Authorea.

Background: Prevention of sudden cardiac death (SCD) has, to date, focused on individuals with advanced heart disease due to the high risk of this population. Yet, the majority of SCD events occur in the general population, in particular those without known heart disease. As cardiovascular testing is generally not recommended in asymptomatic individuals. Our aim was to define the diagnostic gap in the subgroup of a primary care population deemed to be at moderate risk of SCD by a recently developed risk score. Methods: We conducted a cross-sectional study of primary care patients from two large academic institutions and excluded those with coronary artery disease, heart failure, and atrial fibrillation. We calculated the SCD risk score and classified them into low, intermediate and high-risk categories. We evaluated the period prevalence and odds ratio (OR) of echocardiography and stress testing by risk of SCD adjusted for age, gender, race, and ethnicity. Results: We identified 36,885 patients without heart disease from both institutions with a median SCD score of 9% (IQR 3.5-22). The period prevalence of having an echocardiogram was 18% for those in the lowest SCD risk and 36% for those in the highest SCD risk group. The percentage of patients who had a stress test was 18% for those in the lowest SCD risk and 23% for those in the highest SCD risk group. The OR of having any test was 1.09 (1.00-1.18) for those in the intermediate risk category and 1.22 (1.09-1.37) for those in the highest risk category compared to those with the lowest risk. Conclusions: In patients identified to be at moderate risk for SCD in a primary care population, cardiovascular testing occurs in only a third. It is possible that more extensive cardiovascular screening of these patients could detect subclinical disease associated with SCD risk.

Hypertension is a major risk factor for cardiovascular diseases, with high prevalence in low- and high-income countries. Among the various antihypertensive therapeutic strategies, synthetic Angiotensin I-converting enzyme inhibitors (ACEI) are one of the most used pharmacological agents. However, their use in hypertension therapy has been linked to various side effects. In recent years considerable research has been performed on the use of food-derived ACEI peptides (ACEIp) as antihypertensive agents. Although promising, the industrial production of these ACEIp through conventional methods, such as chemical synthesis and enzymatic hydrolysis of food proteins, has been proven troublesome and expensive. Limitations to the large-scale production of ACEIp for functional foods and supplements can be overcome by producing the precursors of these peptides in heterologous hosts. Bacterial hosts have been the privileged choice, particularly to test the success of the genetic engineering strategies, but new platforms based on plants and microalgae have also been emerging. This work provides an overview of the state of antihypertensive therapy, focusing on ACEI, illustrates the latest advances on ACEIp research, and describes current genetic engineer-based approaches for the heterologous production of ACEIp for antihypertensive therapy.

Norcantharidin (NCTD) is a traditional Chinese medicine (TCM) that has been used for over 2000 years to treat many diseases. It can inhibit proliferation and induce apoptosis in multiple types of cancer cells. However, the anticancer activities of NCTD in non-small cell lung cancer (NSCLC) cells, and its underlying mechanisms, have not been investigated. In this study, NCTD suppressed the growth and proliferation of A549 non-small cell lung cancer cells in a dose-dependent manner, apparently by reducing the mitochondrial membrane potential and inducing G2/M phase arrest. NCTD induced apoptosis by increasing the ratio of Bax/Bcl-2 and Bax/Mcl-1 and activating caspase-3/9-dependent mitochondrial pathways. Treatment with NCTD induced significant mitophagy and autophagy, as the demonstrated by accumulation of punctate LC3 in the cytoplasm and the characteristic clustering of the mitochondria around the nucleus, increasing the conversion of LC3-I to LC3-II and reducing the protein expression of p62. In addition, we also observed an increase in p-AMPK, p-JNK and p-c-jun and decrease in p-AKT and mTOR. In conclusion, our results demonstrate that NCTD can reduce the mitochondrial membrane potential and subsequently increase cellular autophagy and apoptosis; the AMPK/mTOR/ULK1, JNK and Akt/mTOR signaling pathways were involved in these processes. Thus, the traditional Chinese medicine NCTD could be a novel therapeutic for treating NSCLC cells.

Civil Engineering projects which include road construction pose a significant amount of risk due to the several activities involved, its coverage over a wide expanse of land and threat from underground conditions. Risk is defined as the chance of something happening that will have an impact on objectives, and this can be either positive or negative. Risk in road construction stem from the conception till usage and has significant effect on any one of the aspects of a project namely cost, quality, time or scope of the project. In addition, sources of risk can be in terms of payment, security deposit and retention, time of commencement and completion, variation, delay and cost of delay and liquidated damages. Size can be one of the major causes of risk; so can changes in political or commercial planning. Early understanding of the risks involved in a project will help project managers to reduce its impacts and complete the project in a sustainable and more efficient manner. This can be achieved through proper Risk Management. Risk Management entails identification, analysis and application of methods to reduce the identified risk. This study focuses on sustainable risk management for road construction projects, taking South east geopolitical zone of Nigeria as case study. The method involved primary data collection using questionnaire survey and data analysis using statistical models. This study establishes that program evaluation review technique is the most effective risk management practice in Nigeria and conforms to sustainable development practices in addition to analytical hierarchy and probability impact methods. The study would help project managers understand anticipated risks in road projects, better estimate risks prior to the commencement of any project and allows them to develop proper mitigation measures at an early stage of a project.

There is a rich amount of information in co-occurrence data that could be used to understand community assembly. This proposition first envisioned by Forbes (1907) and then Diamond (1975) prompted the development of numerous modelling approaches (e.g. null model analysis, co-occurrence networks and, more recently, joint species distribution models). Both theory and experimental evidence support the idea that ecological interactions may affect co-occurrence, but it remains unclear to what extent the signal of interaction can be captured in observational data. The time is now ripe to step back from the statistical developments and critically assess whether co-occurrence data really is a proxy for ecological interactions. In this paper we present a series of arguments based on probability, sampling, food web and coexistence theories supporting that significant spatial associations between species (or the lack of) is a poor proxy for ecological interactions. We discuss appropriate interpretations of co-occurrence, along with potential avenues to extract as much information as possible from such data.

In this study an ion exchange resin-based downstream-processing approach for imine reductase (IRED)-catalyzed reactions was investigated. As a model reaction, 2 methylpyrroline was converted to its corresponding product (S)-2-methylpyrrolodine with >99% of conversion by the (S)-selective IRED from Paenibacillus elgii B69. Under optimized reaction conditions full conversion was achieved using a substrate concentration of 150 mmol·L-1 and 500 mmol·L-1 of D-glucose. Seven commercially available cation and anion exchange resins were studied with respect to their ability to recover the product from the reaction solution. Without any pre-treatment, cation exchange resins Amberlite IR-120(H), IRN-150, Dowex Monosphere 650C and Dowex Marathon MSC showed high capacities (up to >90%). A 150 mL-preparative-scale reaction was performed yielding ca. 1 g product with >99% purity. Any further purification steps, e.g. by column chromatography or recrystallization, were not required.

Owing to increasing penetration of renewable energy sources, it is mandatory to investigate it’s effect on the combined heat and power dynamic economic dispatch. At the same time , adverse effect is there due to highly intermittent nature and higher rate of outages of these sources . This piece of work proposes squirrel search algorithm (SSA) for solving combined heat and power dynamic economic dispatch (CHPDED) incorporating pumped-storage-hydraulic unit captivating uncertainty and outage of renewable energy sources. A lately developed swarm intelligence algorithm SSA, emulates from the dynamic scavenging behavior of squirrel. The competence of the recommended technique is examined on a test system. Simulation outcomes of the proposed technique is harmonized with those acquired by particle swarm optimization (PSO) and grey wolf optimization (GWO). After comparison, a conclusion was made presenting SSA technique conferring with good-quality solution than other techniques.

Models of surface enhancement of molecular electronic response properties are challenging for two reasons: (1) molecule-surface interactions require the simultaneous solution of the molecular and the surface dynamic response (a daunting task); (2) when solving for the electronic structure of the combined molecule+surface system, it is not trivial to single out the particular physical effects responsible for enhancement. To attack this problem, in this work we apply a formally exact decomposition of the system’s response function into subsystem contributions by employing subsystem DFT which grants access to dynamic polarizabilities and optical spectra. In order to access information about the interactions between the subsystems, we extend a previously developed subsystem-based adiabatic connection fluctuation-dissipation theorem of DFT to separate the additive from the nonadditive correlation energy and identify the nonadditive correlation as the van der Waals interactions. As an example, we choose benzene adsorbed on monolayer MoS2. We isolate the contributions to the benzene’s dynamic response arising from the interaction with the surface and for the first time, we evaluate the enhancements to the effective C6 coefficients as a function of benzene-MoS2 distance and adsorption site. We also quantify the spectral broadening of the benzene’s electronic excited states due to their interaction with the surface. We find that the broadening has a similar decay law with the molecule-surface distance as the leading van der Waals interactions (i.e., R-6) and that the surface enhancement of dispersion interactions between benzene molecules is less than 5\%, but still large enough (0.5 kcal/mol) to likely play a role in the prediction of interface morphologies.

In this article, we present a double side highly isolated triple band-notched UWB MIMO antenna for short-range wireless communication applications. The proposed MIMO antenna design provides a UWB band with the notched band at the IEEE INSAT C band satellite communication and WLAN band (4.6–5.9 GHz), the X band uplink and downlink satellite communication (7.70–8.43) and (10.3-10.98 GHz). It has double side placement of polygon-shaped radiating elements, and an inverted L-shaped stub to obtain high isolation between radiating elements. The proposed antenna has a size of 18 × 28 mm2, which operates from 3 to 12 GHz. The antenna characteristics such as isolation between radiating elements, S11/S22, gain, and radiation characteristics are studied. The proposed MIMO antenna has isolation of >19 dB, 0-7.5 dBi peak gain and almost radiation pattern over the entire operating frequency band with pattern diversity. Furthermore, MIMO diversity performance was investigated using an ECC, diversity gain, multiplexing efficiency, TARC, and CCL. The proposed UWB MIMO antenna has very low ECC of 0.0025, and DG of >9.9, over the entire operating band (3-12 GHz). Also, the real-time indoor short-range communication capability of the proposed MIMO antenna demonstrated by using the NI 802.1 framework

Groundwater is a significant resource for water uses. Groundwater depletion is becoming a global issue for water sustainability. Many places of Globe are suffering to decrement of groundwater. India is overexploiting this resource for irrigation, urbanization and industrialization. In this study evaluation of groundwater storage potential is taken into consideration for Bankura district, West Bengal. Periodical data observed from November 2007 to January 2017 is perceived for study purposes. Broadly remote sense method is used in this study. In the present work Gravity Recovery and Climate Experiment (GRACE) technique is applied for predicting groundwater changes. With the inclusion of Global Land Data Assimilation Systems (GLDAS), performance predictor implies good results. Estimation shows groundwater depletion is amounting to be an average rate of 0.35cm/year. September 2011 experienced maximum positive groundwater changes with equivalent thickness of 17.6722 cm, whereas in June 2013 the substantial change of depletion is found to be -24.16828 cm. Both observed and estimated groundwater changes are compared and have established the value of correlation coefficient as 0.827.

Latest advancements has been seen in every industry and there has always been a strong competition in the market amongst industries in term of economy, profits, shares etc. one such industry is construction industry where concrete is the key building substance which is in limelight. Since past, we have seen much advancement in concrete because of the research which is in progress on concrete to come out with a product which should be economical and strong enough to resist all kind of loads. In this research, fly ash and silica fume are used as a replacement for cement and a small percentage of steel fibers were included by volume of concrete. Here, fly ash is replaced by 0%, 15%, 30% and silica fume is replaced by 0%, 6%, 12% and 18% for cement. Initially, a set of concrete specimens were casted with 0%, 15%, 30% fly ash and 0%, 6%, 12% and 18% silica fume with 0% inclusion of steel fibers and experiments were conducted for compressive, flexural and split tensile strength. Secondly, another set of concrete specimens were casted with 0%, 15%, 30% fly ash and 0%, 6%, 12% and 18% silica fume with 0.5% inclusion of steel fibers and tested for the same. Similarly, another set of samples were casted 0%, 15%, 30% fly ash and 0%, 6%, 12% and 18% silica fume with 1% addition of steel fibers and tested to determine the strength parameters of concrete. And it was witnessed that at 15% fly ash and 12% silica fume with 1% steel fiber, compressive strength, split tensile strength and flexural strength were shown a peak value.

This paper aims to establish the exact relationship between Gauss Level and Temperature for a permanent magnet assembly. Magnetrons require a magnetic field to constrain the thermo-electrons emitted from the cathode to form a space charge cloud. The thermo-electrons would simply dissipate at the earth plane rather than form a space charge cloud without this magnetic field. Hence, to ensure optimum performance and consistency of the magnetron, the magnetic field must be calibrated. To calibrate the magnetic field, electromagnets are commonly used as they are highly flexible but they create additional variables such as cost and complexity. After thorough checks to ensure they have the right magnetic field strength, alternative approach is to use permanent magnets. There is some difficulty is measuring field strength accurately using permanent magnets as they are subject to environmental factors such as temperature which affect their magnetic properties. There is the need to compensate for these environmental factors during measurement to ensure accuracy and therefore correct running of a magnetron. Test data was generated through an experiment which was carried out on a permanent magnet sample cycled in temperature while the magnetic field was measured at periodic intervals. A mathematical model generated from test data can then be used for compensation. The Gauss probe used to measure magnetic field was temperature cycled independently to determine the measurement error and a calibration magnet was cycled to validate the data collected in the first experiment.

In this paper a 1x4 array patch antenna designed for (2.4 GHz) frequency. The microstrip line feed technique was used for feeding antenna and a four-way Wilkinson Power Divider designed and simulated for splitting signals to radiating elements. Phase shifter based on switched line technique applied to steer beam to 40 degree. The substrate that used in this paper as dielectric was FR4 of dielectric constant 4.6 and thickness 1.6mm. Design and simulation process were done by Advanced Design System software (ADS 2017).

1. Wild animal populations typically harbour multiple parasite species, which can interact in various ways depending on the species involved and the state of the host upon infection. While many pairwise parasite interactions and within-guild parasite communities have been characterised, understanding how an interaction network spanning multiple parasite groups might be mediated has been less commonly explored. 2. We aimed to characterise parasites associations across guilds in a wild population of a model species, allowing for comparisons with existing laboratory-based research, and better understanding of how any observed associations might manifest within the host. 3. We used cross-sectional data from an island population of the house mouse, Mus musculus domesticus, to identify associations between a broad range of parasite species, including blood-borne microparasites, arthropod ectoparasites, and gastrointestinal and hepatic helminths. 4. Every recorded species was found to exist within a framework of positive and negative associations, involving multiple between-guild associations, and with the under-studied helminth species Calodium hepaticum playing a central role. 5. This study highlights the need to account for as many infections as possible when studying naturally infected populations, due to the prevalence of inter-species associations. Various potential mechanisms, including immunological and ecological, are suggested to explain how these associations might occur. Comparisons with analogous laboratory research from the same species are explored. A need for longitudinal study to determine causality of interactions is highlighted.