Results were moderately sensitive to the long-term effectiveness and cost of treatment for HCV. General results were minimally sensitive to the direct medical costs associated with HIV disease, a potential treatment effect in nonresponders, and minor toxic effects. The impact of major toxic effects depended on assumptions made about the necessity for long-term treatment interruptions with HAART. Figure 3 shows the relationship between the RR of progression to cirrhosis in coinfected patients with mild and moderate chronic HCV compared with HIV-uninfected patients and the incremental cost-effectiveness ratios for combination therapy compared with the next best treatment strategy.
General results for patients with genotype 1 Figure 3 A and non-1 genotypes Figure 3 B are similar, although the optimal strategies for treatment differ. As the RR was increased from 1 ie, risk is no different than in HIV-uninfected patients to 5, the incremental benefits associated with treatment increased and the cost-effectiveness ratios became more attractive.
The impact on the cost-effectiveness ratios associated with treatment was most pronounced between an RR of 1 and 2, with less effect observed at RRs higher than 3. Changes in the RR had a greater effect on patients with mild HCV than with moderate HCV because the former have a lower baseline probability of disease progression. In contrast, minor adverse affects from treatment had little effect on the results. In coinfected patients with mild chronic hepatitis, results were sensitive to assumptions about the impact of treatment on quality of life. The life expectancy benefits from treating mild HCV ranged from 1 to 2 weeks, whereas the QALE benefits ranged from 2 weeks to nearly 2 months Table 2.
These results demonstrate that a substantial proportion of the clinical benefit associated with treating mild chronic HCV results from averting progression to moderate HCV, which is associated with a poorer quality of life. For patients with moderate HCV and genotype 1, the cost-effectiveness of pegylated interferon alfa and ribavirin therapy was sensitive to assumptions about the potential quality of life benefits associated with a single weekly injection compared with the 3 weekly injections needed for regular interferon alfa.
We conducted a threshold analysis to identify the quality of life decrement associated with 3 weekly subcutaneous injections that would make pegylated interferon alfa plus ribavirin the preferred strategy. We also evaluated the cost-effectiveness of interferon alfa—based monotherapy in coinfected patients intolerant of ribavirin. For these patients, monotherapy with pegylated interferon alfa was the most effective option. The incremental benefits and cost-effectiveness of pegylated interferon alfa and ribavirin therapy for 48 weeks compared with use of regular interferon alfa and ribavirin for 24 and 48 weeks differed between individuals with genotype 1 and non-1 genotypes.
In contrast, because treatment is relatively more effective in patients with non-1 genotypes, the incremental gain in QALE associated with the more costly pegylated interferon alfa, compared with regular interferon alfa and ribavirin, was relatively small. For all patients, regardless of genotype, if ribavirin was not tolerated, monotherapy with pegylated interferon alfa was the best option. There is considerable uncertainty in the natural history of chronic HCV, although recent data indicate that the RR of liver disease progression seems to be increased in coinfected patients compared with HIV-uninfected patients.
When we assumed that the risk of liver disease was no different than in HIV-uninfected patients, the life expectancy gains and cost-effectiveness ratios associated with treatment for moderate HCV were comparable or superior to those provided by prophylaxis for opportunistic infections. These results highlight the importance of obtaining better data to inform the attributable excess risk associated with HIV coinfection. The results of this analysis indicate that the information with the greatest potential value will be that providing detail on whether the RR is closer to 1 or 2 in coinfected compared with HIV-uninfected patients.
Therefore, the goal of our exploratory analyses examining the implications of these interactions was to provide qualitative insight into the importance of certain variables but not to answer questions for which data are not yet available. We found that changes in HCV treatment efficacy and minor toxic effects, when varied over a wide plausible range, had a minimal effect on our major results. In contrast, there was a greater effect of major toxic effects when they resulted in a lower efficacy of HAART. Without the clinical benefits associated with HAART, patients experienced HIV disease progression before the development HCV-related end-stage liver disease; thus, they received minimal life-extending benefit from HCV treatment despite accruing its treatment costs.
On the other hand, it is equally plausible that treatment for HCV could improve the probability of tolerance to HAART by reducing the risk of hepatotoxicity. If this turns out to be true, HCV treatment will provide even greater clinical benefits and be even more cost-effective. This study has several additional limitations. The efficacy and toxic effects of HCV therapy in HIV-infected patients have only been assessed in relatively small clinical studies.
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There are no published data, to our knowledge, on the quality of life associated with coinfection, stratified by stage of HIV disease, that are suitable for weighting the specific health states in our model. We assumed a multiplicative relationship between the quality weights for HIV and HCV, but empiric data to inform the validity of this assumption are lacking. The quality of life benefits associated with use of pegylated interferon alfa, recently approved by the Food and Drug Association for treatment of chronic HCV, remain unclear.
It is possible that temporary interruptions in HAART due to HCV treatment toxic effects will be less detrimental than we assumed; in this case, the negative impact of toxic effects was overestimated. Data in these patients are lacking but will be important to incorporate when available. A key attribute of a model such as this one is that as better data become available, the impact of new information can be rapidly evaluated.
In the meantime, however, clinical decisions for individuals and broader public policy decisions must proceed before all uncertainties are resolved. Evaluating the effectiveness of HCV treatment in coinfected patients requires specification of the natural history of both diseases HIV and HCV , consideration of the heterogeneity of risk, treatment efficacy and toxic effects, and accessibility, feasibility, and affordability of medication and health care. Data are not available for all of this information, and our analysis therefore required multiple assumptions.
However, even in the future, a single study will not be able to simultaneously consider all of these components and assess all possible strategies for all relevant populations. This analysis was conducted to provide qualitative and quantitative insight into the relative importance of different components of the treatment process and to investigate how results would change when values of key variables were changed.
By identifying the most influential variables, these results may be used to help prioritize and guide data collection efforts. In patients able to tolerate combination therapy, the choice of pegylated vs standard interferon alfa in combination with ribavirin depends on the genotype and likelihood of sustained treatment response to traditional interferon alfa and ribavirin and assumptions about the quality of life decrement associated with 3 subcutaneous injections per week.
Patients who are intolerant of ribavirin therapy should be treated with pegylated interferon alfa regardless of genotype. Corresponding author and reprints: Sue J. All Rights Reserved. Figure 1. View Large Download. Table 1. Am J Med. Declining morbidity and mortality among patients with advanced human immunodeficiency virus infection.
N Engl J Med. Epidemiology of human immunodeficiency virus—associated opportunistic infections in the United States in the era of highly active antiretroviral therapy. Clin Infect Dis. Accessed April 23, Abstract J Hepatol. Semin Liver Dis. Increasing mortality due to end-stage liver disease in patients with human immunodeficiency virus infection. Changing spectrum of mortality due to human immunodeficiency virus: analysis of deaths during Causes of death among HIV-infected patients in the era of highly active antiretroviral therapy: Aquitane Cohort France, Mortality for liver disease in patients with HIV infection: a cohort study.
J Acquir Immune Defic Syndr. Br J Haematol. High hepatitis C viraemia and impaired antibody response in patients coinfected with HIV. Effect of human immunodeficiency virus on hepatitis C virus infection among injecting drug users. J Infect Dis. Influence of human immunodeficiency virus infection on the course of hepatitis C virus infection: a meta-analysis. Hum Pathol. Retrospective analysis of the impact of HIV infection and alcohol use on chronic hepatitis C in a large cohort of drug users.
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Anti-protease inhibitor therapy decreases the liver fibrosis progression rate in HIV-HCV coinfected patients [abstract]. Mortality from liver cancer and liver disease in haemophilic men and boys in UK given blood products contaminated with hepatitis C. Influence of hepatitis C virus genotypes and HIV infection on histological severity of chronic hepatitis C.
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Hepatitis C virus co-infection is a negative prognostic factor for clinical evolution in human immunodeficiency virus—positive patients. For the deterministic perturbation at early times, trajectories oscillate through the background streamfunction because the perturbation velocities form an azimuthal wave Fig. The frequency of this oscillation depends on the exact location of the trajectory, so with time, trajectories move out of phase due to the cumulative effect of their slightly different oscillatory frequencies.
It takes a few cycles of overturning to develop noticeable spreading, but then the spread grows quickly. For the stochastic perturbation Fig. There are no oscillations in time because the perturbation acts separately on each trajectory at each time step, leading to continuous and monotonic spreading of the ensemble. This spreading is similar to diffusion, but the increase in the range of trajectories does not depend on the gradients of concentration — Fick's law does not apply.
If both perturbations are included Fig. In this example, and over timescales considered, we conclude that the stochastic perturbation dominates at early times but that chaotic spreading takes over at times larger than about Over an even longer time period, turbulent diffusive spreading is expected to overtake chaotic spreading. The spread from the deterministic perturbation is very fast, appearing to be qualitatively exponential, for a period of time, as expected for a region with high FTLEs, which indicates exponential growth on average but is limited to the width of the chaotic region in which the ensemble begins e.
In contrast, the stochastic perturbation will spread with the square root of time until it reaches the cylinder boundaries e. Therefore, the time when the deterministic perturbation has greater spread will be limited to between when fast chaotic-advection-induced separation starts in the deterministic perturbation, which requires sufficient interaction with hyperbolic regions, and when the stochastic perturbation spreads the ensemble to the width of the chaotic region. In the chaotic sea region Fig. The ensembles with deterministic, chaos-inducing perturbations experience an initial delay before they begin quickly growing.
Once rapid growth sets in, they spread to the width of the chaotic region between the times and Larger deterministic perturbations lead to earlier and faster spreading as well as wider chaotic regions.
However, larger deterministic perturbations e. We can also consider the timescales over which diffusive and advective processes with similar kinetic energy red and light blue curves in Fig. The ensembles released in the chaotic sea show that over the first few hundred time steps, turbulent diffusion dominates the spread Fig. After that we see a period of fast growth due to chaotic advection, which quickly overtakes the slower diffusive spreading.
This rapid growth stops when the advective spread reaches the width of the chaotic region, and the diffusive spreading, which is not limited by the chaotic region width, is then able to catch up and exceed chaotic advection. Of course, these processes will be acting at the same time, not separately; the green curves in Fig. In this case, spreading of the ensemble begins immediately, as in simulations with only stochastic perturbations, but then has a time period of pronounced growth and some oscillations, as seen in simulations with only steady perturbations.
In these cases, the same behavior as in the chaotic sea region occurs for the spreading under stochastic perturbations Fig. From the spreading of ensembles of trajectories, we see that the wider chaotic regions are where chaotic advection dominates over turbulent diffusion at least over some time intervals , as expected from our scaling arguments.
However, those scalings did not include considerations of time including considerations of when fast chaotic-advection-induced stretching begins, as FTLEs are time averages; the delay in chaotic stretching decreases the period of time when chaotic advection is important. This time period begins when fast advective stretching is first apparent and ends when turbulent diffusion has spread across the region under consideration.
From these ensembles, we would expect a set of passive 3-D drifters or an injected tracer beginning in a blob to spread out diffusively, be stretched and folded throughout the chaotic sea, producing strong filamentation, then gradually diffuse across the barriers of the chaotic sea and into the remainder of the eddy. During the later stage, tracer variance due to the formation of filaments by chaotic advection would be gradually eroded by turbulent diffusion.
This sequence of events will be apparent in tracer simulations shown in the next section. In a , the dashed black line is 10 - 5 t. In this section we analyze the effects of the symmetry-breaking, chaos-inducing deterministic velocity perturbation on the stirring and mixing of a diffusive tracer in a dynamically consistent numerical model of a rotating cylinder flow. The distributions of passive tracers like dye are created by the advective and diffusive patterns without the feedback onto the flow that would occur with temperature or salinity, allowing for insight into those processes.
For our simulations we turn away from the kinematic model and take advantage of the existing numerical model that solves Navier—Stokes equations corresponding to the rotating cylinder flow accompanied by integration of the advection—diffusion equation with diffusivity k for a passive tracer, both described in P As discussed earlier, these simulations have the advantage of being dynamically consistent at the cost of being computationally expensive, whereas economy of the kinematic model allows us to explore a wider range of parameters. Our main quantification tool is Nakamura's effective diffusivity: a background diffusivity scaled by a representation of the stretching of dye concentration contours by advection.
For our fully three-dimensional system with constant density, the effective diffusivity can be written as. It is not clear how one would incorporate a scale-dependent diffusivity into Nakamura's formulation. The volume V is a one-to-one mapping of tracer concentration and volume such that V C is the volume occupied by fluid with concentrations greater than C.
Larger effective diffusivity leads to larger diffusive fluxes of tracer. This amplification can be understood as being caused by advective stretching and folding of tracer contours which increases the area of surfaces of constant C , thereby amplifying gradients of C and speeding up diffusive fluxes. Both advection and diffusion redistribute tracer concentration and influence effective diffusivity.
The effective diffusivity allows the effects of advection to be included in a diffusive term:. Then, as diffusion smooths the tracer field, wiping away the filaments, gradients decrease and contours become smoother, with a lower surface-area-to-volume ratio. We compare the effective diffusivity with a deterministic perturbation to that without; any increase is due to increased stirring, which gives a quantitative measure of how important that stirring is for the distribution of tracer in each region of the flow. Stirring increases the variance of a tracer, while mixing decreases it.
The numerical simulations are run using the solver NEK for several diffusivities and strengths of the symmetry-breaking deterministic perturbation. The domain has an identical radius and height, matching the aspect ratio assumed in our kinematic model. The symmetry-breaking perturbation is created by moving the central axis of the imposed surface lid stress a fraction of the radius X 0 from the cylinder axis so that X 0 becomes the primary parameter determining the perturbation strength.
The set of simulations performed allows for an examination of the effects of changing E , k , and X 0. Each simulation is run for a time of after the tracer is initialized. The evolution in time of the tracer variance function and Nakamura effective diffusivity integrated over the volume of the cylinder are described first; we then discuss the evolution of the dye and finally the spatial characteristics of the Nakamura effective diffusivity.
The tracer variance function over time Fig. The function then has a single maximum that occurs at the time when diffusive mixing starts to overcome stirring so that the variance of the tracer begins to decrease. The maximum occurs earlier when either the imposed diffusivity or the strength of the deterministic perturbation increases.
Increasing the diffusivity makes the maximum occur earlier by increasing the strength of the mixing Fig. Increasing the deterministic perturbation also makes the maximum occur earlier, as faster stirring creates larger gradients, in turn increasing diffusive fluxes Fig. The maximum of the tracer variance function increases with decreased diffusivity, as more filamentation can occur before diffusion wipes the filaments out.
Changes in the maximum as the size of X 0 is increased from 0 to 0. At long times, here meaning after many overturns but before diffusion removes all gradients, the shape of tracer surfaces is distorted nested tori look ahead to Fig. This value is shown as black dashed lines in Fig.
Nevertheless, these plots can yield some insights into the time histories shown in Fig. The two are laid out differently, with the former designed to emphasize the effects of varying k and the latter designed to explore variations in the strength X 0 of the perturbation.
In all cases, the C sections become smoother and their range decreases between the snapshots, due to continued mixing. For an initial broad gradient in any direction, we expect the same realignment after the first few overturnings as the tracer is passively advected by the background velocity field.
We believe, then, that the tracer distribution that exists at later times is somewhat independent of initial distribution. The latter is somewhat surprising, since we have already seen Fig. It is possible that slight increases in stirring in the perturbed cases have caused more mixing than in the unperturbed cases, even over the short interval before these snapshots, leading to a lower range of C and smaller average gradients in the perturbed cases.
However, the volume-integrated measures Fig. To begin with, a comparison of Fig. As Fig. Thus the combined effect of smaller diffusivity and finer filaments i. Here a comparison between the unperturbed and perturbed cases contrast Fig.
Decreasing the value of k again has the effect of creating a more fine structure Fig. So far, the consequences of the symmetry-breaking disturbance are modest. The tracer distribution is markedly distorted at early times compare Fig. Overall, these dye experiments show that chaotic advection enhances Nakamura effective diffusivity within the chaotic sea at some times in all cases examined. The amount of enhancement is controlled by both the size of the perturbation and the imposed diffusivity.
The main goal of this work is to establish whether the stirring due to chaotic advection in an idealized model of an upper ocean eddy remains relevant in the presence of levels of background turbulent diffusion that are consistent with observations. The answer is that chaotic advection can indeed be relevant, and in some cases dominant, within certain regions of the flow field and over certain time intervals. The region most likely to feel the effects of chaotic advection is the extensive chaotic sea that exists in all simulations, and this is especially pronounced when the eddy is shallow.
Chaotic stirring in the smaller and more isolated resonant regions is less likely to be important. This conclusion comes with many caveats related to idealizations e. A second focus of the work has been to explore different bases for comparison of the effects of chaotic advection and homogeneous turbulent diffusion. To this end we have identified three metrics for comparison and are now in a position to discuss their advantages and disadvantages.
The first metric is the Lagrangian Batchelor scale Sect. Below the Batchelor scale, diffusion is stronger than advection. When this width is smaller than that of the chaotic regions, advection dominates; when it is larger, diffusion dominates. Interpretation of the Lagrangian Batchelor scale analysis would appear to be straightforward, but it does not comprehend the fact that chaotic advection may only be dominant over a finite-time interval, which is averaged in the FTLEs.
Even when the level of background turbulent diffusion is weak, it will eventually spread beyond the region of Lagrangian chaos. As a second basis for comparison, we computed the dispersion over time of initially small clusters of trajectories Sect. Background turbulent diffusion is simulated as a Lagrangian random walk based on spatially uniform diffusivity. We consider the dispersion characteristics that arise when this representation of turbulent diffusion is added to a background flow with no chaotic advection and compare it to flows that are undergoing chaotic advection but lack turbulent diffusion.
Since the chaotic regions occupy sub-volumes of the entire eddy, spread of trajectories or tracers due to turbulent diffusion will eventually surpass that due to chaotic advection: chaos alone cannot distribute parcels across Lagrangian boundaries. However, it remains meaningful to compare the rate of spreading of parcels at earlier times. One immediate observation is that the character of ensemble spreading is qualitatively different for advective as opposed to diffusive perturbations.
For the former, the spreading rate is significantly enhanced at some key times when trajectories pass near strong hyperbolic regions. In the latter case, the spread grows similarly to the square root of time at all times. These results are in agreement with the Batchelor scale analysis. These results are not in strict agreement with the Batchelor scale analysis Fig. To reconcile these inconsistencies, note that as E gets small, a greater percentage of the eddy volume becomes occupied by an inviscid, vertically rigid interior.
For a very small E , parcels experience relatively low levels of strain while rising or descending through the region. A Batchelor scale that is based only on a single parameter measuring the time-averaged contraction over several overturning cycles may be too simplistic when a parcel divides its time between kinematically distinct regions. This method of comparison based on parcel spreading has several advantages over the Batchelor scale. First, it offers a direct measure of fluid stirring. Also, it reveals information about the time history of dispersion that is hidden in the Lagrangian Batchelor scale analysis.
Disadvantages include the fact that the analysis, as presented, does not account for scale-dependent diffusivity. Also, like the Batchelor scale analysis, it requires the tracking of fluid parcels in 3-D, something that is currently difficult in the ocean. The third method for comparison Sect. We consider a flow with a given background turbulent diffusivity, k , and calculate how much the irreversible property exchange is amplified as a result of chaotic stirring.
The chaotic sea region generally has enhanced values compared to the interior and its resonant regions. With a larger perturbation, chaotic advection dramatically changes the effective diffusivity, but there are also stronger barriers present, evident from isolated areas with different tracer concentrations. We conclude that the spatial structures of chaotic and regular regions can play an important role in how a tracer is distributed.
The use of effective diffusivity as a metric has several advantages. First of all, it provides a direct measure of irreversible property exchange between regions with different dye concentration. Its time history leads to insights about the evolution of mixing and, in particular, the time periods when chaotic advection is most relevant.
Also, it can be measured, at least in principle, by performing an ocean dye release and measuring the dye concentration along sections that cut through the dye plume at different depths or angles, all in an attempt to recreate a concentration map in 3-D. Of the three methods proposed herein, it would appear to be the one most testable by ocean observations. The main disadvantage of effective diffusivity is that it requires the background diffusivity to be constant, which is strictly true only if the diffusivity is interpreted as the molecular diffusivity.
In this work, we examined the relative strengths of advection and diffusion for the redistribution of a passive tracer in a rotating cylinder flow as an analogue for an overturning submesoscale eddy. Since a major challenge of this work was developing ways of thinking about the competition between chaotic advection and turbulent diffusion, the numerical experiments described in this paper have been necessarily idealized. Although the focus of this current paper is on the behavior of a steady 3-D eddy flow subject to a turbulent diffusion, similar results are expected to hold for 3-D eddy flows with time-periodic and time-quasi-periodic behavior.
Exploration with models that are more realistic for the ocean presents a number of challenges, including the development of more anisotropic and spatially varying representations of turbulence to account for differences between the ocean surface mixed layer and the stratified fluid underneath. In addition, finite eddy lifetimes must be confronted, as a separation of timescales between feature lifetimes and the periods of trajectories within them is needed for these analyses.
Here we provide detail about the fixed points, and their bifurcations, of the background velocity field in the kinematic model of the rotating cylinder. Then we present the bifurcation diagram and an example of the flow with many fixed points in the overturning streamfunction. The overturning streamfunction is described by Eqs. However, additional points with zero vertical and radial velocity exist, which correspond to circular periodic orbits in the horizontal plane and which we refer to as r z -fixed points.
The Soviet high command's decision to focus on one cost-effective design, cutting costs and simplifying production wherever possible while only allowing relatively minor improvements, had proven to be an astute choice for the first two years of the war. However, the battles in the summer of demonstrated that the Soviet tank crews struggled at longer ranges with the additional frontal armour applied to the later variants of the Panzer III and Panzer IV, and were unable to penetrate the frontal armour of the new German Panther or Tiger I tank at standard combat ranges without tungsten rounds, and had to rely on tactical skill through flanking maneuvers and combined arms.
This new tank, the T , was intended to be a universal tank to replace both the T and the KV-1 heavy tank.grimovmedersu.ga
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Not only were the weapons of German tanks improving, so was their armour. It was still not enough to match the Tiger, as a Tiger could destroy the T from a distance of 1, to 2, meters,  but it was a noticeable improvement. With the T canceled, the Soviet command made the decision to retool the factories to produce an improved version of the T Now the tank commander needed only to command aided by cupola and radio systems , leaving the operation of the gun to the gunner and the loader.
This made the turret, overall, a bigger target due to the three-man crew and bigger gun , but more resistant to enemy fire. Production of the T began in January at Factory No. A T initially cost about 30 percent more to produce than a Model , at , rubles ; by this had been reduced to , rubles.
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While it could not match the armour or weapons of the heavier Panther and Tiger tanks, its improved firepower made it much more effective than earlier models, and overall it was more cost-effective than the heaviest German tanks. In comparison with the T program, the Germans instead chose an upgrade path based on the introduction of completely new, expensive, heavier, and more complex tanks, greatly slowing the growth of their tank production and aiding the Soviets in maintaining a substantial numerical superiority in tanks.
The German army often employed as much captured materiel as possible and Ts were not an exception. Fighting on the Eastern Front saw large numbers of Ts captured, though few were Ts. These were designated by the Germans as Panzerkampfwagen T r. From late , captured Ts were transported to a German workshop for repairs and modification to German requirements. In a local tank factory in Kharkov was used for this purpose. These were sometimes modified to German standards by the installation of a German commander's cupola and radio equipment.
The first captured Ts entered German service during the summer of In order to prevent recognition mistakes, large-dimension crosses or even swastikas were painted on the tanks, including on top of the turret, in order to prevent strikes from Axis aircraft. Badly damaged tanks were either dug in as pillboxes or were used for testing and training purposes. Just after midnight on 9 August , though the terrain was believed by the Japanese to be impassable by armoured formations, the Soviet Union invaded Japanese-occupied Manchuria.
Red Army combined-arms forces achieved complete surprise and used a powerful, deep-penetrating attack in a classic double encirclement pattern, spearheaded by the T The opposing Japanese forces had been reduced as elite units had been drawn off to other fronts and the remaining forces were in the middle of a redeployment. The Japanese tanks remaining to face them were all held in the rear and not used in combat; the Japanese had weak support from IJAAF forces, engineering, and communications. Japanese forces were overwhelmed, though some put up resistance. The Japanese emperor transmitted a surrender order on 14 August, but the Kwangtung Army was not given a formal cease-fire until 17 August.
By the time the invading North Korean troops were forced to withdraw from the south, about Ts and 74 SU assault guns had been lost or abandoned. Despite China's entry into the conflict in the following month, no major armour deployments were carried out by them, as the Chinese focus was on massed infantry attacks rather than large-scale armour assaults. Several Ts and a few IS-2 tanks were fielded, primarily dispersed amongst their infantry, thus making armoured engagements with US and UN forces rare from then on.
In summary, a US military survey concluded that there were, in all, tanks vs. One of the last modern conflicts which saw the extensive combat deployment of the T was the Angolan Civil War. In early , the Yugoslav People's Army possessed Ts, none of which were in active service. In , they were used as regular tanks to support Egyptian infantry, the tank was still in use by the October war.
Ts equipped many of the armies of Eastern European countries later forming the Warsaw Pact and the armies of other Soviet client-states elsewhere. Ts were sporadically available in Afghanistan. During the Soviet-Afghan War , most of the Ts were fielded by the Sarandoy internal security forces. Some were also kept in service with the Army of the Democratic Republic of Afghanistan. Although during decades of service time there are plenty of modifications that make some visual differences between original T and the Chinese T, and the factory had the ability to produce every single part of T, there was no single T that actually produced in China.
The production plan of the T in China was ended soon after once the PRC received TA main battle tanks from the Soviet Union and began to build the Type 59 tank, which was a licensed production version of TA. Cuba received T tanks as military aid from the Soviet Union in Many T tanks first saw action in April during the Bay of Pigs Invasion with an unknown number destroyed or knocked out during the battle.
The tanks were based along with a company of Cuban mechanized infantry equipped with BTR armoured personnel carriers. The Cuban forces were mobilised to stop them. As they approached Cassinga they were strafed by South African aircraft, which destroyed most of the BTRs and three of the Ts; a fourth T was disabled by an anti-tank mine buried in the road. The remaining tank continued to engage the withdrawing South African paratroops from a hull down position until the battle was over.
Over a hundred Cuban Ts and their respective crews remained in Angola as of the mid s. Cypriot National Guard forces equipped with some 35 T tanks helped to support a coup by the Greek junta against President Archbishop Makarios on 15 July They also saw extensive action against Turkish forces during the Turkish invasion in July and August , with two major actions at Kioneli and at Kyrenia on 20 July By most of them had been stationed near Luanda, where their crews received training from Cuban instructors.
South Africa accused SWAPO of planning a major offensive to influence Namibia's pending general elections , but the tank crews remained stationary and even refrained from intervening in a series of renewed clashes later that year. The Soviet and Finnish armies used Ts until the s; the former included the The Finnish tanks were captured directly from the Soviets or purchased from Germany's captured stocks. In , both T Model tanks and SU self-propelled guns were photographed being used in Houthi takeover in Yemen. In , pre-war development of a more advanced T tank was resumed, leading to the T The new tank had a turret design based on the T's, but featured a new hull with torsion-bar suspension and transversely mounted engine ; it had a lower profile than the T and was simpler to manufacture.
Between and of these tanks were built before the end of the war.
A T tank monument in the East German city of Karl-Marx-Stadt Chemnitz became the target of a bomb-attack that inflicted minor damage on the vehicle and blew out nearby windows. The bomber, Josef Kneifel , was sentenced to life imprisonment in Bautzen , but was released after a deal with the West German government in After German unification in , the tank was transferred to a museum in Ingolstadt.
Another such tank, mounted atop the monument to Soviet tank crews in Prague , was the focus of significant controversy. The monument known locally as 'Saint Tank' was intended to represent Lt I. Goncharenko's T the first Soviet tank to enter Prague during the liberation of Czechoslovakia in May , but actually bore an IS-2M heavy tank. To many in Prague, the tank was also a reminder of the Soviet invasion which ended the Prague Spring of Four Tankers and a Dog Czterej pancerni i pies , a very successful war-themed Polish television series of the s, adapted the novel of the same name by the Polish writer Janusz Przymanowski — , himself a People's Army of Poland volunteer.
The series made T tank number an icon of Polish popular culture. It was also shown in other Soviet-bloc countries where it was also well received, surprisingly even in the German Democratic Republic East Germany. At the beginning of the 21st century reruns of the black and white series still manage to attract a large audience. In Budapest on 23 October , the protests in Hungary climaxed during the 50th anniversary of the Hungarian Revolution of Protesters managed to start an unarmed T tank which was part of a memorial exhibit, and used it in riots against police forces.
The tank drove a few hundred metres, then stopped in front of the police, causing no personal injury. There were two main production families of the T, each with subvariants. The identification of T variants can be complicated. Turret castings, superficial details, and equipment differed between factories; new features were added in the middle of production runs, or retrofitted to older tanks; damaged tanks were rebuilt, sometimes with the addition of newer-model equipment and even new turrets.
The Red Army never had a consistent policy for naming the T Some Russian historians use different names: they refer to the first T as the T Model instead of , all Ts with the original turret and F gun as Model instead of Models and , and the hexagonal -turret T as Model instead of When the German Wehrmacht used captured Ts, it designated them Panzerkampfwagen T r , where the "r" stood for russisch "Russian". All T models are externally very similar. An enormous number of Ts and Ts were produced; the Soviets used them aggressively in campaigns in Europe and Asia, and they were distributed to the Soviets' allies all over the world.
Due to all three factors, there are hundreds of surviving Ts. Examples of this tank are in the collections of most significant military museums, and hundreds more serve as war memorials. Many are in private ownership, and demilitarised working tanks change hands for U.
Some still may serve in a second-line capacity in a number of Third World militaries, while others may find use in a civilian capacity, primarily in film-making. In , a T Model was recovered that had spent 56 years at the bottom of a bog in Estonia. The anaerobic environment of the bog preserved the tank and ensured there were no signs of oil leakage, rust, or other significant water damage.
The engine was restored to full working order. Other significant surviving Ts include a Model at the U. Army Ordnance Museum in Aberdeen, Maryland —one of the oldest surviving vehicles. The French Musee des Blindes at Saumur holds two Ts, including one in full working condition that is displayed in action at its summer "Carrousel" live tank exhibition. From Wikipedia, the free encyclopedia. Second World War Soviet medium tank. This article is about the Soviet medium tank.
For other uses, see T34 disambiguation. T tank. World War II tanks. List Category. Cold War tanks. Post—Cold War tanks. This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. Main article: Soviet invasion of Manchuria. Main article: T variants. Retrieved on 18 May Two ways to build a better mousetrap. Ohio: Ohio State University. Operation Barbarossa and Germany's Defeat in the East.
New York: Cambridge university press. Panzer Leader. London: Penguin Classics. Los Angeles: Pinnacle Books. Retrieved Soviet Casualties and Combat Losses. The Military Balance London: IISS. Dunn, Jr Mechanicsburg, PA: Stackpole Books. Paton Electric Welding Institute. Retrieved November 17, Hoover Press The Journal of Slavic Military Studies. Hurlich" PDF. Mark Conrad, Red Army Handbook — Sutton Publishing. Archived from the original on