scholarly journals Virulence evolution of a parasite infecting male and female hosts

2017 ◽  
Author(s):  
Alison M. Wardlaw ◽  
Aneil F. Agrawal
Keyword(s):  
Death Rate ◽  
Host Population ◽  
Reproductive Value ◽  
Contact Pattern ◽  
Male And Female ◽  
Virulence Evolution ◽  
Host Type ◽  
Contact Patterns ◽  
Exploitation Rate ◽  
Evolutionarily Stable

AbstractParasites experience different tradeoffs between transmission and virulence in male and female hosts if the sexes vary in life history or disease-related traits. We determine the evolutionarily stable levels of exploitation by pathogens under two scenarios: an unconstrained pathogen that expresses different exploitation rates within each host type as well as a pathogen constrained to express the same exploitation rate in each sex. We show that an unconstrained horizontally-transmitted parasite evolves to express the same sex-specific exploitation rate within each sex as it would in a host population composed entirely of hosts with that sex’s resistance and intrinsic death rate. In contrast, the ESS exploitation rate of a constrained pathogen is affected by sex-differences in susceptibility and non-random contact patterns between host types that differ in resistance. As the amount of within-sex transmission increases, the ESS shifts closer to the optimum trait value in the more susceptible sex. Allowing for some degree of vertical transmission, the exploitation rate expressed in females (but not males) changes with contact pattern even in unconstrained pathogens. Differences in contact pattern and susceptibility play an important role in determining the ESS exploitation rate by shifting the reproductive value of each host type.

scholarly journals ASPEK BIOLOGI DAN PARAMETER POPULASI UDANG JINGA (Metapenaeus affinis H. Milne Edwards, 1837) DI PERAIRAN KOTABARU, KALIMANTAN SELATAN

2017 ◽  
Vol 9 (1) ◽  
pp. 11
Author(s):  
Tirtadanu Tirtadanu ◽  
Suprapto Suprapto ◽  
Ali Suman
Keyword(s):  
Growth Parameters ◽  
Growth Function ◽  
Fishing Effort ◽  
Population Parameters ◽  
Male And Female ◽  
Management Measures ◽  
Exploitation Rate ◽  
Mean Size ◽  
Biological Aspects ◽  
The Mean

Udang jinga (Metapenaeus affinis H. Milne Edwards, 1837) merupakan salah satu jenis udang ekonomis penting yang diusahakan di perairan Kotabaru dan saat ini produksinya cenderung mengalami penurunan. Salah satu data dan informasi yang diperlukan dalam mengkaji tingkat pemanfaatan dan dasar pengelolaannya adalah aspek biologi dan parameter populasi. Penelitian ini bertujuan mengkaji aspek biologi dan parameter populasi udang jinga sebagai bahan kebijakan pengelolaan perikanan udang di perairan Kotabaru, Kalimantan Selatan. Penelitian dilakukan pada bulan Januari – November 2016 di perairan Kotabaru. Parameter pertumbuhan diestimasi berdasarkan pergeseran modus struktur ukuran panjang dengan metode ELEFAN I. Hasil penelitian menunjukkan rata-rata ukuran udang jinga (M. affinis) betina yang tertangkap adalah 23,6 ± 3,45 mmCL dengan modus ukuran 24 mmCL dan rata-rata ukuran udang jantan adalah 20,7 ± 2,9 mm dengan modus ukuran 18 mmCL. Nisbah kelamin udang jinga jantan dan betina adalah 1 : 2,5. Musim pemijahan udang jinga diduga berlangsung sepanjang tahun dan puncak pada bulan Maret. Ukuran rata-rata pertama kali tertangkap (Lc) udang lebih kecil dari ukuran rata-rata pertama kali matang gonad (Lm) (21,7 < 28,5 mm CL) sehingga sebagian besar udang tertangkap berukuran kecil dan belum memijah. Persamaan pertumbuhan udang jinga jantan  CL(t)=35,95(1-e-2.02(t+0,31) dan udang jinga betina CL(t)= 38,3(1-e-1,92(t+0,29)). Tingkat pemanfaatan udang (E) menunjukkan lebih tangkap (overfishing) yakni 0,70/tahun pada jantan dan 0,73/tahun pada betina. Dengan demikian disarankan untuk melakukan pengurangan upaya penangkapan sebesar 40% dan penutupan musim penangkapan di bulan Maret.The jinga shrimp (Metapenaeus affinis H. Milne Edwards, 1837) was one of important commodity that was exploited in Kotabaru Waters, yet the production tend to be declined recently. The data and information on biological aspects and population parameters are needed to investigate the exploitation level and the basis of management measures. This research aims to investigate the biological aspects and population parameters of jinga shrimp Kotabaru waters, South of Kalimantan. This research was conducted on January – November 2016. The growth parameters were estimated as movement of length frequency mode by ELEFAN I method. The results showed that the mean size of female jinga shrimp (M. affinis) was 23,6 ± 3,45 mm CL and the mode was 24 mmCL. While, the mean size of male jinga shrimp was 20,7 ± 2.9 mm CL and the mode was 18 mmCL. The sex ratio of male and female shrimp was 1 : 2,5 . Spawning season of jinga shrimp was estimated throughout the year and the peak was in March. The length at first captured (Lc) was shorter than length at first matured (Lm) (21,7 < 28,5 mm CL). That means most of the catches was immature. The growth function of male and female jinga shrimp were and, CL(t)=35,95(1-e-2.02(t+0,31) respectively and CL(t)= 38,3(1-e-1,92(t+0,29)). The exploitation rate (E) of male and female shrimp fishing were  0,70/year 0,73/year, respectively. The reduction of fishing effort needed by 40% of the actual combined with the temporal fishing closure March.

scholarly journals Evolution of virulence when transmission occurs before disease

2010 ◽  
Vol 6 (4) ◽  
pp. 505-508 ◽  
Author(s):  
Erik E. Osnas ◽  
Andrew P. Dobson
Keyword(s):  
Recovery Rate ◽  
Transition Rate ◽  
Transmission Rate ◽  
Evolutionarily Stable Strategy ◽  
Relative Difference ◽  
Stable Strategy ◽  
New Host ◽  
Virulence Evolution ◽  
Evolution Of Virulence ◽  
Evolutionarily Stable

Most models of virulence evolution assume that transmission and virulence are constant during an infection. In many viral (HIV and influenza), bacterial (TB) and prion (BSE and CWD) systems, disease-induced mortality occurs long after the host becomes infectious. Therefore, we constructed a model with two infected classes that differ in transmission rate and virulence in order to understand how the evolutionarily stable strategy (ESS) depends on the relative difference in transmission and virulence between classes, on the transition rate between classes and on the recovery rate from the second class. We find that ESS virulence decreases when expressed early in the infection or when transmission occurs late in an infection. When virulence occurred relatively equally in each class and there was disease recovery, ESS virulence increased with increased transition rate. In contrast, ESS virulence first increased and then decreased with transition rate when there was little virulence early in the infection and a rapid recovery rate. This model predicts that ESS virulence is highly dependent on the timing of transmission and pathology after infection; thus, pathogen evolution may either increase or decrease virulence after emergence in a new host.

Magnitude and Spatial Distribution of Impact Intensity Under the Foot Relates to Initial Foot Contact Pattern

2017 ◽  
Vol 33 (6) ◽  
pp. 431-436 ◽  
Author(s):  
Bastiaan Breine ◽  
Philippe Malcolm ◽  
Veerle Segers ◽  
Joeri Gerlo ◽  
Rud Derie ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Loading Rate ◽  
Ground Reaction Forces ◽  
Contact Pattern ◽  
Intensity Measure ◽  
Foot Kinematics ◽  
Contact Patterns ◽  
Reaction Forces ◽  
Local Impact ◽  
The Impact

In running, foot contact patterns (rear-, mid-, or forefoot contact) influence impact intensity and initial ankle and foot kinematics. The aim of the study was to compare impact intensity and its spatial distribution under the foot between different foot contact patterns. Forty-nine subjects ran at 3.2 m·s−1 over a level runway while ground reaction forces (GRF) and shoe-surface pressures were recorded and foot contact pattern was determined. A 4-zone footmask (forefoot, midfoot, medial and lateral rearfoot) assessed the spatial distribution of the vertical GRF under the foot. We calculated peak vertical instantaneous loading rate of the GRF (VILR) per foot zone as the impact intensity measure. Midfoot contact patterns were shown to have the lowest, and atypical rearfoot contact patterns the highest impact intensities, respectively. The greatest local impact intensity was mainly situated under the rear- and midfoot for the typical rearfoot contact patterns, under the midfoot for the atypical rearfoot contact patterns, and under the mid- and forefoot for the midfoot contact patterns. These findings indicate that different foot contact patterns could benefit from cushioning in different shoe zones.

scholarly journals Analysis Model of Giant Prawns Population (Macrobrachium rosenbergii) in Estuary Edge of Sembakung Waters, Nunukan, Indonesia

2020 ◽  
Vol 12 (2) ◽  
pp. 236
Author(s):  
Agus Indarjo ◽  
Gazali Salim ◽  
Christine Dyta Nugraeni ◽  
Lukman Yudho Prakoso ◽  
Permana Ari Soejarwo ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Growth Pattern ◽  
Growth Characteristic ◽  
Macrobrachium Rosenbergii ◽  
Survey Method ◽  
Natural Mortality ◽  
Von Bertalanffy ◽  
Male Mortality ◽  
Male And Female ◽  
Exploitation Rate

HighlightThe sex ratio of giant prawns in the waters of fe- male groceries is 3 times higher than that of males.The growth characteristic of male and female   giant   prawns   is   negative   allometry, but the male and female body shapes are fat.Total   mortality, capture mortality, catch rate, male prawns are higher than females.The male infinitive growth is longer than the female,but the female’s growth rate is faster than male.AbstractGiant prawns (Macrobrachium rosenbergii) is a crustacean class that has the larg- est size and its habitat in Sembakung waters included brackish water (estuarine) with a salinity variable of 6.5+0.5 ppt and a temperature variable of 28.5+0.5OC and a variable pH of 6 (acidic). The objective of this research was to analyze the growth and mortality model of giant prawns (M. rosenbergii) that was taken from the catch of fisherman in the estuary, Sembakung sub-district, Nunukan Regency, Indonesia. The study was conducted for 3 months from November 2019 to Janu- ary 2020. The sampling was by using a survey method with purposive judgment sampling based on a catch of 14 fishermen who used the bottom fish pot from Sembakung waters, Nunukan Regency (Indonesia). The data collection included data of sex, total length, and the total weight of giant prawns. While analysis was employed for growth pattern, condition index, Von Bertalanffy growth, and mor- tality. The results obtain the sex ratio of male and female giant prawns 1:3.67. The growth pattern of male and female giant prawns were allometric negative. The growth of the von Bertalanffy model for infinitive growth of male giant prawns were 21.219 cm and female were 18.42 cm, respectively the mortality from giant prawns obtain total male mortality is 2,257, catch mortality is 1.92 and natural mortality is 33.75% with an exploitation rate of 0.85 (85%). The total female mor- tality is 1.528, catch mortality is 120.1% and natural mortality is 32.69% with an exploitation rate of 0.786 (78.6%).

scholarly journals Virulence evolution of multiple infections with vertically and horizontally transmitted fungal species in a natural plant system

2020 ◽  
Author(s):  
Kai Fang ◽  
Jie Zhou ◽  
Lin Chen ◽  
Yu-Xuan Li ◽  
Ai-Ling Yang ◽  
...  
Keyword(s):  
Invasive Plant ◽  
Horizontal Transmission ◽  
Experimental Studies ◽  
Fungal Species ◽  
Host Population ◽  
Transmission Mode ◽  
Multiple Infections ◽  
Plant Host ◽  
Susceptible Host ◽  
Virulence Evolution

AbstractThe virulence evolution of multiple infections of parasites from the same species has been modelled widely in evolution theory, and the trajectories of evolution are relevant to parasite transmission mode, as well as to parasite and host population dynamics. However, experimental studies on this topic remain scarce, particularly regarding multiple infections by different parasite species. In this study, we employed the invasive plant Ageratina adenophora to verify the predictions made by the model. We observed that A. adenophora was a highly susceptible host to phylogenetically diverse foliar pathogens with mixed vertical and horizontal transmission within leaf spots. The pathogen community structure at the leaf spot level was determined by transmission mode. Over time, the pathogen community decreased in diversity; meanwhile, the vertically transmitted pathogens exhibited decreased virulence to the host A. adenophora, but the horizontally transmitted pathogens exhibited increased virulence to the host. Our results demonstrate that the predictions of classical models are still valid in a complex environment. Moreover, we propose that it is very important to determine whether the primary foliar pathogen of a given plant host is relevant to seedborne fungi, as this characteristic is an important factor in understanding pathogen-host interactions.

Evaluation System of Tooth Contact Patterns of Hypoid Gears Using Artificial Intelligence

2012 ◽  
Author(s):  
Morimasa Nakamura ◽  
Keisuke Kojima ◽  
Ichiro Moriwaki
Keyword(s):  
Neural Network ◽  
Artificial Intelligence ◽  
Evaluation System ◽  
Gear Pair ◽  
Contact Pattern ◽  
Hypoid Gear ◽  
Tooth Contact ◽  
Contact Patterns ◽  
The Neural Network ◽  
Hypoid Gear Pairs

Tooth contact inspection is one of the most common methods for checking qualities of hypoid gear pairs. A change in machine setting parameters for cutting and lapping processes of a hypoid gear pair enables a tooth contact pattern of a hypoid gear pair to be varied. The deviation of the pattern from the target one is represented by a grade point. In the inspection, the qualities of hypoid gear pairs are usually classified into only two grades; OK or NG. However, in order to conduct a follow-up survey on problems of the products and to be useful to be trouble shooting tasks of the end products, finer classifications and more quantitative evaluations of tooth contact patterns could be effective. Such approaches have been tried, however, only experienced and well-trained technicians for the inspection of hypoid gear pairs can determine the point of each tooth contact pattern. And it is difficult to make this evaluation method automatic. To overcome this problem, an application of artificial intelligence system must be useful. The present paper describes a computer evaluation system using the neural network, which is a kind of the artificial intelligence systems, for tooth contact patterns of hypoid gear pairs which can evaluate the results of the inspections instead of experienced hypoid gear technicians. This system with the neural network has a capability to learn relationships between evaluation grade points of tooth contact patterns given by the hypoid gear technicians and graphics of tooth contact patterns of hypoid gear pairs. Moreover, it can return the evaluation grade points when a tooth contact pattern is input into the system. The evaluation performance of the developed system was discussed. And a quality of normative tooth contact patterns, which were used as the teacher signals for training the neural network system, greatly affected its performance. The comparison of evaluated grade points obtained from developed system with the technician’s ones showed that the correct answer ratio obtained from the developed system was about 90% in the best case.

The relationship between immunocompetence during winter and subsequent reproductive decisions and survival in the Great Tit

2008 ◽  
Vol 58 (2) ◽  
pp. 199-209 ◽  
Author(s):  
Rianne Pinxten ◽  
Marcel Eens ◽  
Frank Adriaensen ◽  
Erik Matthysen ◽  
Tinne Snoeijs
Keyword(s):  
Immune Response ◽  
Breeding Season ◽  
Parus Major ◽  
Reproductive Value ◽  
Laying Date ◽  
Lifetime Reproductive Success ◽  
Winter Period ◽  
Reproductive Decisions ◽  
Term Survival ◽  
Male And Female

AbstractThe typical costs associated with parasitism have led to the suggestion that immunosuppression in the host may be an important mechanism mediating the life history cost of reproduction, defined as a decrease in residual reproductive value as a consequence of parental effort. More immunocompetent individuals have therefore been predicted to reveal higher fitness through more optimal reproductive decisions and increased survival. In this study, we simulated a challenge to the immune system of male and female great tits (Parus major) by injecting a novel but harmless antigen, sheep red blood cells (SRBC), and related the elicited immune response to (long-term) survival and reproductive traits, relevant to the determination of lifetime reproductive success in this species. In females, we could not detect any relationships between humoral immunocompetence and laying date, clutch size, or mean fledging mass during the breeding season following the winter period during which we assessed the immune response. Furthermore, immune response to SRBC did not predict survival of male and female great tits until the following breeding season as well as until the breeding season the year after. Overall, humoral immunological quality measured during winter did not predict important fitness components in great tits.

Robust Optimization of the Loaded Contact Pattern in Hypoid Gears With Uncertain Misalignments

2009 ◽  
Author(s):  
M. Gabiccini ◽  
A. Bracci ◽  
M. Guiggiani
Keyword(s):  
Optimization Problems ◽  
Optimization Procedure ◽  
Target Area ◽  
Contact Pattern ◽  
Unified Framework ◽  
Hypoid Gears ◽  
Contact Patterns ◽  
Unconstrained Nonlinear Optimization ◽  
The One ◽  
Micro Topography

This paper presents an automatic procedure to optimize the loaded tooth contact pattern of face-milled hypoid gears with misalignments varying within prescribed ranges. A two-step approach is proposed to solve the problem: in the first step, the pinion tooth micro-topography is automatically modified to bring the perturbed contact patterns (as the assembly errors are varied within the tolerance limits) match a target area of the tooth, while keeping them off the edges; in the second step, a subset of the machine-tool settings is identified to obtain the required topography modifications. Both steps are formulated and solved as unconstrained nonlinear optimization problems. While the general methodology is similar to the one recently proposed by the same authors for the optimization at nominal conditions, here the robustness issues with respect to misalignment variations are considered and directly included in the optimization procedure: no a posteriori check for robustness is therefore required. Numerical tests show that nominally satisfactory and globally robust hypoid pairs can be designed by a direct process and within a unified framework, thus avoiding tiresome trial-and-error loops.

scholarly journals Examination of the contact pattern of rolling surfaces

2019 ◽  
Vol 9 (2) ◽  
pp. 38-43
Author(s):  
Ferenc Sarka
Keyword(s):  
Operating Conditions ◽  
Contact Pattern ◽  
Rolling Bearings ◽  
Contact Patterns ◽  
Potential Applications ◽  
Gear Drives ◽  
Shape And Size

This article provides a brief summary of the potential applications of contact pattern examinations. The examination of contact pattern is a frequently used test for gear drives, rolling bearings and checking support rollers. It is used on gear drives and support rollers to test operating conditions, whereas in the case of rolling bearings the cause of the failure has already been identified. The chapters mention the types of contact patterns, the shape and size of contact patterns. This article is an introduction to a multi-part article series that presents the computerbased capabilities of contact pattern examination.

scholarly journals Clinical Figure and Rate of Mortality Among Chronic Schizophrenics: A Local Assessment

2020 ◽  
Vol 2 (02) ◽  
pp. 01-04
Author(s):  
Saeed Shafti
Keyword(s):  
Mental Disorders ◽  
Life Expectancy ◽  
Cause Of Death ◽  
Death Rate ◽  
Psychiatric Patients ◽  
Crude Death Rate ◽  
Aged Patients ◽  
Male And Female ◽  
Female Patients ◽  
Schizophrenic Patients

Introduction: Researchers have consistently reported that people with mental disorders have elevated mortality compared with the general population. In Iran there are not systematic psychiatric case registers that could allow us to study precisely the mortality of psychiatric patients. The aim of the current study was to determine the mortality rate and clinical profile of death in a group of non-western chronic elderly schizophrenic patients. Methods: chronic geriatric subdivision of Razi Psychiatric hospital with a capacity around 220 beds (110 for each of male and female elderly patients) had been selected as the specific arena of investigation. For the present retrospective survey, all recorded deceases during the last sixty months (April of 2014-August 2019) in the said senior wards had been included in the current study. Clinical diagnosis, too, was essentially based on ‘Diagnostic and Statistical Manual of Mental Disorders’, 5th edition (DSM-5). Results: Among eight-hundreds and frothy chronic elderly schizophrenic patients, sixty-nine deceases had been registered by the mortality committee of the hospital. As said by results, the annual rate of mortality among elderly schizophrenic patients in the present assessment was around 0.015 (0.15 per 1,000 individuals per year) and 0.017 (0.17 per 1,000 individuals per year) among male and female aged patients, respectively, which were significantly lower than current native crude death rate (p<0.000). While the age of the expired female patients was significantly more than the died male schizophrenics (p < 0.001), the life expectancy of both male and female expired patients was significantly shorter than the public’s life expectancy (p< 0.000). Besides, in the present evaluation, while cardiac illness was the main leading cause of death among old schizophrenics, reasons like suicide, falls, drug use or tuberculosis, were not applicable at all. Conclusion: While the rate of mortality among elderly schizophrenics was significantly lower than public’s crude death rate, age of the deceased female patients was significantly longer than the male expired patients and life expectancy of both male and female died patients was significantly lower than native public’s life expectancy. Cardiac disorder, as well, was the main leading cause of death among aged schizophrenic patients.

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