Organizations have been going through drastic structural changes in the last two decades and been competing more to survive in the global market. Some characteristics have been added to new organizations like decentralization, globalization, extensive use of information technology and most importantly extensive use of work groups and teams. As already mentioned by Anderson et al., in   , one of the most important changes is going from individual efforts to group efforts.
The concept of social group was first configured through the researches, studies and observations in the 1970s and 1980s   . This phrase was then used to describe and explore the interpersonal relations in the work place. All through 1990s many studies were done to make us better understand this phenomenon and a lot of researchers took the time to reach above goal. It is clear that the most important question to be considered is whether work groups and teams have positive, negative or no effect on organizations.
Many researchers have a positive view on this and believe that mechanisms in teams can improve efficiency and effectiveness in work places (Kozlowski, et al.   ).
More importantly the leading characteristic which rises to teams` support is the ability that they provide for companies whose environment is changing so fast that becoming conformed to it faces a big challenge. Teams in this environment can make the response much faster because it uses the ideas of a group of experts in no time   .
Many factors in teamwork make it a good choice for management to consider using it; here however, five most important ones have been selected and explained in this paper.
The rest of this paper is organized as follows: The main work team characteristics have been explained in Section 2. The applied methodology and the data collection tool have been introduced in Sections 3 and 4 respectively. Section 5 provides the research results followed by discussion and some final conclusions are in Sections 5 and 6.
2. Team Work Characteristics
Many factors in teamwork make it a good choice for management to consider using it. In this research, however we have picked out the five most important ones including: team structure, leadership, control, mutual support and communication. The level of social interdependence and members` mutual support has positive effect on higher sales  . The mutual support can be an important factor for measuring cooperation and correlation in organizations.
According to the series of interviews that Hambrick  did with a number of big corporates’ CEOs almost all of them agreed upon one important barrier on the way to a successful team which was lacking mutual support and correlation.
In every organization, information must reach each member through a complicated procedure of communication. Communicative and informational role of managers is one of their most important roles, which has to be orchestrated very well.
The factors which have a leading role in the success of a team are:
1) Size: teams with members between 12 and 25 function better so the less members, the more successful the team will be.
2) Place: the closer the members (Physically) the better function they will have.
Regular meetings, the accessibility of information, focus on one task and etc., these characteristics are considered as team structure  .
3) Leadership: leadership is an impartible part of management. Leadership is defined as the ability to influence on a group of people to reach a goal and has a leading role in management’s duties.
4) Control: the process of comparing what was meant to do and what is done and amending in case of the difference between the two. In Control, we compare musts with existents and desirable with available  .
On the other hand, recently human resources excellence is one of the eminent characteristics of a successful manager. Empowering employees is distribution of legal authority amongst them in a way they feel effective in their environment  . Most administrators imagine they have realized the meaning of empowering employees but in fact, very few have grasped the meaning and even so among these very few know how to use it  .
Researches show that empowered employees are happier, more satisfied with their jobs, more efficient, more innovative and produce and offer productions and services with a greater quality  .
Many employees think of empowering employees as doing whatever they feel right freely but it means to release the inner forces in each human to reach excellent results. It means to render power to help employees feel confident inside   .
This study is a descriptive survey research. The study sample is consisted of staff Torang Darya Shipping Company. After compiling a list of all employees, for the object of determining the size of sample, we have used Cochran formula and as seen in below formula 207 of the staff were selected. The survey questionnaire was distributed among them and finally, 200 questionnaires were collected.
1By E. Salas et al., 2012, the model of the present research has been taken by the same research.
4. Data Collection Tool
4.1. Work Teams Effects Questionnaire1
This questionnaire  consists of 20 items and five subscales which include:
・ Team Structure,
・ Mutual Support,
Every item has a 5 degree of response, from “completely disagree” to “completely agree” that it is graded from 1 to 5. The scope of the questionnaire is from 66 to 88% using both Cronbach’s alpha and split up methods, which shows appropriate validation.
2By Richard L. Daft, 2012.
4.2. Empowering Employees Questionnaire2
This questionnaire  consists of 22 items and three subscales which are included: Delegation, Motivation, Team work. Every item has a 5 degree of response, from “completely disagree” to “completely agree” that it is graded from 1 to 5. The Scope of the questionnaire is from 66 to 88% using both Cronbach’s alpha and split up methods, which shows appropriate validation.
In order to analyze the survey data, both descriptive and inferential statistical methods were used. Table 1 shows the results of Kolmogorov-Smirnov test. Frequency distribution of variables based on the sex and age have been presented in Table 2 & Table 3. Table 2 shows the descriptive characteristics of sex- variables. Table 3 shows the descriptive characteristics of age-variables.
Figure 1 depicts the standardized values in the final model achieved by LIS- REL structural equation modeling (SEM).
Table 1. Results of Kolmogorov-Smirnov Test.
Table 2. Descriptive characteristics of variables-sex.
Table 6 shows the results of the t student test of variables of work teams on HRE.
Table 3. Descriptive characteristics of variables―age.
Table 4. Descriptive characteristics of variables―level of education.
Table 5. Descriptive characteristics of variables―experience.
Figure 1. Standardized values in the final model achieved by LISREL.
Table 6. Results of the t student test of variables of work teams on HRE.
The purpose of this study was to determine the contribution of work teams (team structure, leadership, communication, mutual support and control in predicting human resources excellence and empowerment in Torang Darya Shipping Company. Results of t student test showed that, there is a significant positive relationship between work teams and HRE. The result of each test should be higher than 2 (p > 2) in order to be considered significant and as can be seen above all the criteria has the same significance except mutual support which means it cannot be said about this variable that has any kind of meaningful effect on HRE. The other variables have a meaningful contribution in predicting the HRE. These finding are consistent with the findings of Salas and colleagues   .
In explanation of the above findings, it can be stated that, when employees are put together as a team they can achieve the advantages in the team and improve their role both as a single member of an organization and also as a member of their own team so they will show better performance in the future due to the skills and knowledge that have learnt through their work team experience.
The increasing use of teams and group-works to answer to the requirements of environment ﬂexibility has shown a great interest among academics and professionals  . Many research and studies have been done on this area including     . It has been shown that the team working plays an important role in the organizational success in a global, changeable and client-oriented economy  .
We began this article by highlighting the centrality and importance of teamwork across a wide landscape of modern life. Yet, given the centrality of work teams, it is more than a bit remarkable that we have a strong individual-centric perspective in our culture. We school our children as individuals, we hire, train, and reward employees as individuals. And yet we have great faith that individuals thrown together into a team with little thought devoted to team composition, training and development, and leadership will be effective and successful  .
More over theorists and researchers have developed effective interventions centering on team design, team training, and team leadership that shape team processes and enhance team performance.
One important subject which was left out due to the totality of the matter in the paper is that we have numerable number of teams such as project teams, independent teams, management teams, temporary teams, leadership teams and many others which in their own way have their special structure and effects on the members and are composed for a unique and different reason. By more entering this subject as the view of each special team, it is possible that we can even find out and explore more magic that can happen within them.
In summary, this paper has sought to review the literature on team effectiveness and compile variables and their measures and also their effects on human resources excellence. The results of this work can support future research on teams. Although considerable headway has been made in team effects studies, there is still research to be done.
The research was supported by Shahid Beheshti University of Tehran, Tarbiat Modarres University of Tehran and Khatam Al-anbiya University (KAU). We thank Mr. A. Soori and Mr. A. Karimi for their comments and assistance with preparing the earlier version of the manuscript.